Why are most of the demigods in Percy Jackson ADHD and dyslexic?

Question: As many of you Percy Jackson fans know, the demigods can have ADHD and dyslexia. and a lot of them do. Can you explain why this is the case please? This is what bugs me the most.
Comment: While I don't feel it's worth downvoting, since I like to encourage curiosity, the answer was literally the second result in Google from typing in *Percy Jackson ADHD*. :)
Answer: From the Riordan wiki entry for ADHD

Most demigods are labeled as suffering from ADHD, but it is actually a sign of their heightened senses and natural aptitude for battle. ADHD also gives demigods greater battlefield reflexes and the ability to see where their opponents will strike due to the tensing of their muscles. It is usually coupled with dyslexia in demigods.

and Dyslexia

However, through the Percy Jackson and the Olympians series and beyond, Percy Jackson, along with other demigods, suffer from dyslexia. This is explained to Percy by Annabeth Chase, who informs him that their dyslexia is a result of demigods' brains being "hard-wired" to interpret Ancient Greek, not English. It is usually coupled with ADHD.

So, long story short, it's a natural consequence of their divine abilities. Their brains are wired for combat with heightened senses, so they're constantly noticing things about their environment, which distracts them, and their brains are wired for a language different from English, which makes comprehension difficult.
Out of universe, Rick Riordan's son, Haley Riordan, has both dyslexia and ADHD and he patterned Percy after his son.

When I was writing Percy Jackson, my own son was in the process of being tested for learning differences. He was having trouble reading, and some trouble focusing in the classroom. The teachers were wondering about ADHD and dyslexia. He was frustrated about learning to read, and we had to explain to him that the testing was designed to help the teachers help him, not to make him feel bad….
  dyslexic/ADHD kids are creative, "outside-the-box" thinkers. They have to be, because they don't see or solve problems the same way other kids do. In school, unfortunately, they are sometimes written off as lazy, unmotivated, rude, or even stupid. They aren't. If they can get through their rough school years, they often go on to become very successful adults. Employers love them, because they come up with original, fresh ideas. Making Percy ADHD/dyslexic was my way of honoring the potential of all the kids I've known who have those conditions. It's not a bad thing to be different. Sometimes, it's the mark of being very, very talented. That's what Percy discovers about himself in The Lightning Thief.
Answer: The book explains it as "heightened senses" (that's not a direct quote) so they are better on the battlefield. Personally I think that sounds very dumb (and I have it). Also, dyslexia was described by saying his mind was wired for Greek writing (also dumb) although it is a very  good book series.

"How—"
  "Diagnosed with dyslexia. Probably ADHD, too."
  I tried to swallow my embarrassment. "What does that have to do with anything?"
  "Taken together, it's almost a sure sign. The letters float off the page when you read, right? That's because your brain is hardwired for ancient Greek. And the ADHD—you're impulsive, can't sit still in the classroom. That's your battlefield reflexes. In a real fight, they'd keep you alive. As for the attention problems, that's because you see too much, Percy, not too little. Your senses are better than a regular mortal's. Of course the teachers want you medicated. Most of them are monsters. They don't want you seeing them for what they are."
Percy Jackson & the Olympians, book 1: The Lighting Thief, chapter 6: "I Become Supreme Lord of the Bathroom"
Comment: Can you provide some more insight into the answer and why you dislike it, your post is quite confusing to read imho.


Can I create a virtualbox server that manages all lan traffic and only when running?

Question: I'm running a Windows 7 host and a Linux Mint guest vm in Virtualbox using a bridged adapter. I have multiple web sites set up in the guest os. Currently, I can only access the page at var/www/html from the host by ip address. All sites use var/www/site.name as their root.
The goal is to be able to access any site configured on the guest using any capable device on the lan. But, there's a catch...
In theory anyway, what I'd like to do is have the vm take over all requests to the internet when it is running. So that, if a site is configured on the guest it will serve the lan version to the device that requests it. However, the physical machine I am working on is not always running and this is a home network which uses a cheapo(limited functionality) router provided by the Isp.
I started to set up bind9 on the guest to handle Dns using this tutorial, but it seems like I'd have to point all devices to it with static ip addresses and that I would manually have to keep up with device/site changes to the lan. I'm also not sure how that will affect the network when the vm is not present.
The tutorial also mentions the ability to have DHCP pass updates to the Dns records, but then I can only use the vm DHCP which means I would have to have it running all of the time. Is that right?
Anyhow, I'm out of my element when it comes to networking in general. Is there a way to spin up a vm and have it serve its virtualhosts to the lan, preferably without continually editing devices and files?
Answer: Not the full answer, but some thoughts.
If the devices in you network uses DHCP to get the ip address, you can configure the DNS Server details also in the DHCP server. Then you VM can run a DNS Server which will map URLs to absolute paths (like IP-Address/location/). You can give the IP address of your VM (DNS Server) on top (in DNS list), then the IP of a normal DNS (like google dns (22.214.171.124)).
If your VM is not running, browser will first try your VM's IP, if no response, it will try the consequent DNSs, hence will resolve the URL.


Why is it that denuding something means you strip it rather than dress it?

Question: When we denude something we strip it, like the branches of a tree. That seems a bit inverted to me, shouldn't it be to nude-something?
Comment: GR. http://www.etymonline.com/index.php?term=denude http://www.etymonline.com/index.php?term=denudation
Comment: Like we *skin* a goat and *dress* a chicken.
Comment: And we *dust* the furniture.
Comment: Dust the top of the cake lightly with icing sugar.
Comment: @DavidWallace *Dusting* in this case is akin to *icing* -- not removing something off the cake, but applying sugar *dust*.
Answer: Prefixes can have multiple uses. In the case of denude:

Origin:
late Middle English: from Latin denudare, from de- 'completely' + nudare 'to bare' (from nudus 'naked')
Comment: *de* ='completely' surprises me, though. Waiting to up vote.
Comment: In fact, that definition can decide the very validity of OP's question, and therefore if it should be closed.
Comment: @Kris some [definitions of de-](http://dictionary.reference.com/browse/de-) could mean *intensity*.
Answer: Because sometimes Latin's de- prefix meant something else than to strip something away or to undo or reverse the action of a verb. And so it also has come down to us as something else in English.
You were thinking of OED sense 6, so here are the OED's senses 3–5 for de- to illustrate just a few of the other possibilities for that prefix:

3. Down to the bottom, completely; hence thoroughly on and on, away; also methodically, formally:

as dēclāmāre to shout away, declaim;
dēclārāre to make quite clear, declare;
dēnūdāre to strip quite bare, denude;
dēplōrāre to weep as lost, deplore;
dērelinquĕre to abandon completely, derelict;
dēspoliāre to spoil utterly, despoil.

b. To exhaustion, to the dregs:

as dēcoquĕre to boil down or away, decoct;
dēliquēscĕre to melt away, deliquesce.

4. In a bad sense, so as to put down or subject to some indignity:

as dēcipĕre to take in, deceive;
dēlūdĕre to make game of, delude;
dērīdēre to laugh to scorn, deride;
dētestārī to abominate, detest.

5. In late L., dēcompositus was used by the grammarians in the sense 'formed or derived from a compound (word)', passing later into that of 'compounded over again, doubly or further compounded'; in this sense the word has in modern times been taken into chemistry, botany, etc. (see decomposite, decompound), and the prefix has been similarly used in other words, as decomplex, demixture.

There actually is a word that is constructed and means what you seem to be expecting of denude, and that is debare.  Again per the OED:

trans. To strip down, make quite bare.
Hence  † deˈbared ppl. a. So  † deˈbare a., intensive of bare a.

1567 Drant Horace's Arte of Poetrie A ij, ― As wooddes are made debayre of leaues by turnyng of the yeare.
C. 1620 T. Robinson M. Magd. 223 ― Next her debared brests bewitch mine eyes.

As you see, it hasn't been used much for quite some time.  The OED labels it obsolete.  Best stick with denude.
Answer: Though tchrist's answer is clearly correct, and the OED's sense 3 of de- governs the word denude, I was surprised to discover that Merriam-Webster's Eleventh Collegiate Dictionary doesn't provide a useful answer to the OP's question.
In its entry for denude, the Eleventh Collegiate gives the etymology as

ME, fr. L denuduare, fr. de- + nudus bare

But that dictionary's entry for de- is disappointingly incomplete:

de- prefix [ME, fr. AF de-, des-, partly fr. L de- down, from, away (fr. de, prep.) and partly fr. L dis-; L de akin to OIr di from OE tō to—more at dis-] 1 a : to do the opposite of [deactivate] b : reverse of [de-emphasis] 2 a : remove (a specified thing) from [delouse] b : remove (from) a specified thing [dethone] 3 : reduce [devalue] 4 : something derived from (a specific thing) [decompound] : derived from something (of a specified nature) [denominative] 5 : get off of (a specified thing) [detrain] 6 : having a a molecule characterized by the removal of one or more atoms (of a specified element) [**deoxy*-]

The only definition here that is even remotely related to the OED's clear and succinct "down to the bottom, completely" definition of de- is the fourth one, which, besides being worded rather vaguely (in effect, "something derived from something else of a particular kind" as a noun and "being derived from something of a particular kind" as an adjective), doesn't offer an associated verb form with a definition along the lines of "derive from (something of a specified nature) [denominate]."
Merriam-Webster's treatment of de- appears to leave unexplained such common de- verbs in English as default, delimit, denote, denude, and despoil.
Answer: No, it should not.
You are assuming that the verb denude has been constructed from the adjective nude.
That is not the case. The latin root is dēnūdō (and hence present infinitive dēnūdāre, perfect active dēnūdāvī, supine dēnūdātum.)
Comment: You could cite a reference to be helpful. In fact, it is *de* + *nude* alright, just that *nudere* itself here has the meaning "to strip," derived in turn from *nude*, bare. See links at comment under OP.


timeout for asynchronous web service call in C#

Question: I am using C# and created a proxy from a ASP.Net asmx Web Service at client side, by using Add Web Reference... feature of VSTS 2008.
And I am using the asynchronous method call model (i.e. call the AsyncXXX method, which will return immediately) and handles the complete event (I add event handler to handle the complete even when the reponse is received from server side).
I find if there is no response from server for a long time, the complete event will not be fired.
My questions are,

Is it expected feature or my bug that if no response from server after call AsyncXXX method, complete event handler will not be called?
Are there any way to assign timeout value -- so that I do not wait on the complete event handler infinitely?

thanks in advance,
George
Answer: In the web.config for your webservice you can set a timeout (You will also need to change to not be in debug mode if it is).  This should then cause it to throw an exception that will raise your completed event.  You will then need to inspect for an exception to see if it passed or failed.
<system.web>
    <httpRuntime executionTimeout="120" />
</system.web>

Comment: Thanks ck, which exact config item in web.config do you mean?
Comment:
See http://msdn.microsoft.com/en-us/library/e1f13641.aspx
Answer: If you want your web service to never timeout you can put this line in the web services class:
this.Timeout = System.Threading.Timeout.Infinite;

Answer: SoapHttpClientProtocol which your proxy should inherit from has a Timeout property inherited from its ancestor WebClientProtocol. It could answer your second question.


Orchestra recordings only in piano concertos

Question: I have been thinking about doing a piano recital on my party in July and planned on doing Bach harpsichord concerto no.1, but there aren't any recordings of the orchestra only. Do any of you know how I could find those kinds of recordings with the orchestra playing only so I could play along.?
Answer: There used to be a series of records called Music Minus One which released many concerto recordings with only the orchestra. Perhaps a search on "Music Minus One" may help. They are still around: http://digital.musicminusone.com/
The other possibility is to find a stereo recording where the soloist has been fed to both channels equally. The channels can be electronically subtracted (in the old days by hooking up speakers hot left to hot right with the grounds connected) but one may be able to a DAW to do this electronically. The orchestra will be out of phase with itself (like a big echo) but still able to be used for practice.
It seems that MM1 has BWV 1052 http://digital.musicminusone.com/j-s-bach-concerto-in-d-minor-bwv1052-digitally-remastered-2-cd-set.html
Comment: But can it ship the product from a country to another country?
Comment: There are "remailer" companies that will (for a small fee) buy things in one country and send them to another country. They are often cheaper than using direct shipments (or so I'm told.) I've never used one.
Answer: You could try a MIDI rendition, there are quite good ones out there, just do a google search. With a MIDI player that allows you instrument selection of muting (VanBasco Karaoke Player is good one and very simple to use), you can mute the harpsichord and play on top.
Now, soundwise a MIDI rendition will only be as good as the sounds you have available. The default windows General Midi sounds will surely not fulfil your expectations about the sound of a Baroque orchesta, not by a long shot. Perhaps you have a friend with a DAW software and a nice orchestral synthesizer that can create a rendition for you.
Comment: Using a MIDI player might not work so well if the soloist and orchestra must start at the same time. Instead of using a straight MIDI player I've imported the orchestral midi parts into Sibelius and added a count-in click - I was preparing the Hummel Trumpet Concerto and the third movement starts with the soloist alone so you can't do it without a click. You can mute the click once the orchestra has started. I'm currently using the same technique preparing to perform the Haydn Trumpet Concerto.


Custom URLs for Facebook Ads not Showing Conversions in Google Analytics?

Question: I am using Facebook's dynamic url parameters in our paid ads and all metrics are showing except for conversion data (transaction/revenue) in Google Analytics. All the UTMs have validated and all parameters (source/medium/campaign) show correctly in Google Analytics as well. Just no conversion data. We use 'static' UTM codes all the time with no issues. Does anyone know what might be happening here? Is this a Facebook or Google issue most likely? Should I try using 'static' url parameters in our Facebook Ads and see if that works? Finally, we are using Google Analytics standard and enhanced ecommerce tracking.
Answer: I discovered that as long as the Facebook Pixel and Google Analytics Tag are properly installed and configured and that you have accounted for differences in attribution models, date-of-click vs date-of-purchase, cross-site device tracking & view-through conversions not being tracked by Analytics, etc. that there is little what you can do to fix the data discrepancy between this two platforms.
Answer: Ok, so from what I understand, you want to track your purchases as conversion events and also then track the revenue, transaction details etc. Google analytics or FIrebase by default has events set up especially for this but which will only track your website or app transactions events if you set up their sdk/tracking events code. If you want to use your own events for tracking, you will have to set up something what Google calls - Custom events. For these custom events to show on your dashboard, you will have to set up BigQuery first to map these events and then would need at least 1000+ triggers or conversion for Google to start showing them. This is a big hassle.
Here's what I would suggest to you alternatively, which I am too using. Set up Segment.io for your website/app which will help you to track your events. Then with Segment.io as the source, make a destination for Amplitude.com to create charts and analysis to understand your product events. Segment basically helps you to set up custom events and then with that set up, you can send the triggers of these events to any destination you want. This saves the developer from coding multiple times for different platforms. You can send segment triggers to various destinations like facebook, google analytics, amplitude etc.


Usage of "elliptical" sentence

Question: Please explain an "elliptical" sentence.  Is it used as a shortcut of implied ascription?
Comment: Check your spellings. Do some homework. Show the results. If you still have an issue, try asking first on [ell.se] -- on ELU questions of elementary nature or general reference may promptly get closed or worse, down voted.
Comment: Did you mean http://en.wikipedia.org/wiki/Ellipsis_%28linguistics%29 ?
Comment: . . . a thinly veiled Hermionism.
Answer: An ellipsis is an omission of a logically and/or grammatically necessary element from a sentence.  Don't confuse this omission with the identically-named punctuation, which indicates omission.  An elliptical sentence is one where an element has been left out, but the logic and meaning of the sentence remains clear.  These are the dogs I want to train.  Here is a perfectly fine sentence with two subjects and two verbs that in no way are compounded; it almost seems to consist of two independent clauses.  What it obviously means is "Here are the dogs that I want to train.  The relative pronoun that was elided, left out, in the first example making it an elliptical sentence.  (Just to confuse matters, this kind of an ellipsis (omission) does not require an ellipsis (punctuation).  I suspect that you've asked you question because of the confusion the use of one word to mean two related, but different, ideas has caused.
The answer posted before this one seems to be talking about a third meaning of ellipsis, a rhetorical tool where a portion of the narrative left out for practical, stylistic or other reasons.
Answer: Just as you might describe the shape of an ellipse as a form turning back on itself, so that it heads in no particular direction, so does an elliptical sentence work: Such a sentence does not yield its meaning immediately, as say, a pointed sentence might.  When one is being elliptical, one is being obscure, and hard to parse.
For example: Suppose you did not want to attract the attentions of censors and officious power brokers—often found prospering under totalitarian regimes—when writing about topics and ideas that interest you.  A geneticist trying to communicate to another one about science in Lysenkoist Russia, perhaps. If you needed to refer to these censors, and their community, you might be elliptical or indirect in your references and writings, so that you might speak your mind, freely, right under their noses.
Whatever an elliptical sentence is, it's not a shortcut of "implied ascription." That is a terse sentence; in fact, your definition seems fairly antonymic to me.
Comment: In all of that you haven't given an example of an 'eliptical sentence'.
Comment: Seems to be a bit obscure itself  "...he is stronger than I." seems merely fewer words to ascribe something alost in a shorthand wat but not obscure
Comment: "Ellipsis" is not a helpful term, since it simply means "leaving something out". Leaving things out usually results in an ungrammatical utterance; but under the appropriate circumstances, it may be the result of one or more of a large number of syntactic rules that delete specific material, under specific circumstances, either optionally or obligatorily. None of these qualifications are helped calling it "elliptical"; on the contrary, giving it a pseudoscientific Greek name is sposta mean one understands it, than which nothing can be further from the truth.
Answer: An elliptical sentence, when all is said and done, leaves out an otherwise necessary element from your sentence: Ready when you are. After you!

Usage of "elliptical" sentence


GE model numbers

Question: I'm trying to order some drum slides, Upper Drum support, felt drum seal and timer for a 15-20 year old GE electric cloths dryer. Contacting GE as well as the owners manual and several sites on the web say the SN/ model number should be on the front case with the door open. There is no tag in this area. I have compared the pictures of the control panel in owners manual with my dryer and figured out it is a DVLR223. Only problem is this is only the base model number and I need the whole number to buy parts. Is there any way to tell what those letters after the base number mean?
Comment: It may be the distributor. I'm pretty sure different stores will sometimes sell the same product with unique product numbers to avoid price matching their competitors.
Answer: The letters at the very end generally refer to the style or color of the appliance. W = White, B = Black, Q = "Bisque" (almond, off-white), S = Stainless etc. For an internal part it probably won't matter since you won't have to consider color.

GE model numbers


How old is SUN ☉?

Question: How do we know/calculate the exact age of sun ☉ ? ie. 4.57 billion years. What is the way to calculate it?
Answer: I'm not familiar with nucleocosmochronology (mentioned by Gugg), but traditionally the age of the Solar System, and therefore of the Sun, has been estimated by dating meteorites using uranium decay.
The material that makes up the Solar System was formed in supernovae, and this forms the two isotopes of uranium, U-238 and U-235, in an allegedly well known ratio. The two isotopes decay at different rates and as their end products produce different isotopes of lead. So if you take a meteorite and measure the relative amounts of U-238, U-235, Pb-206 and Pb-207, you can estimate the age of the meteorite. The oldest meteorites are aound 4.57Gyrs old so we assume the Sun is this age as well.
i used the word "allegedly" above because I believe there is some debate about the correct U-238 to U-235 ratio, though the argument is over only very minor corrections to the ratio. Also the material that formed the Solar System may have come from many supernovae rather than just one, so there would be a spread of the formation dates.
I don't know a great deal about this area, but the above should be a good basis for Googling for more detail.
Answer:
The Sun was formed about 4.57 billion years ago from the collapse of part of a giant molecular cloud that consisted mostly of hydrogen and helium and which probably gave birth to many other stars. This age is estimated using computer models of stellar evolution and through nucleocosmochronology. The result is consistent with the radiometric date of the oldest Solar System material, at 4.567 billion years ago. Studies of ancient meteorites reveal traces of stable daughter nuclei of short-lived isotopes, such as iron-60, that form only in exploding, short-lived stars. This indicates that one or more supernovae must have occurred near the location where the Sun formed. A shock wave from a nearby supernova would have triggered the formation of the Sun by compressing the gases within the molecular cloud, and causing certain regions to collapse under their own gravity. As one fragment of the cloud collapsed it also began to rotate due to conservation of angular momentum and heat up with the increasing pressure. Much of the mass became concentrated in the center, while the rest flattened out into a disk which would become the planets and other solar system bodies. Gravity and pressure within the core of the cloud generated a lot of heat as it accreted more gas from the surrounding disk, eventually triggering nuclear fusion. Thus, the Sun was born.

Wikipedia
Also see The age of the Sun and the relativistic corrections in the EOS.
Answer: We do know that the solar system has formed along with the sun (being a third generation star). There are some isotopes distributed (though rarely) throughout the solar system. In Earth, we can do a radio dating for such decaying elements, which can be found in rocks, meteorite locations, etc..
For confirmation, we can check our observations along other areas of our planet, or some other planet in our own solar system. Now, there are many other methods to determine the age, especially using the Standard model of astrophysicists.
Another way is to have a look at the luminosity and spectra of other stars (star clusters can provide more data, as there is a lump) using the standard parallax measurement, plot them in the H-R diagram and finally compare the observed main-sequence stars with sun, and thereby have a guess on its total age...
Comment: I don't think the spectroscopic method will provide a way to calculate its past age accurately, but we can still calculate its lifetime ;-)

How old is SUN ☉?


Is running a DNS server on XenServer a bad idea?

Question: I have a cluster of servers running Xenserver 5.6 that host web email and VoIP services. I'm currently considering setting up a chrooted bind server on each Xenserver host (I mean on the actual server not inside a VM)
Is this a bad idea?
Answer: As a general rule, I'd advise against running anything other than the absolute bare minimum of services in the Xen Dom0 (the privileged domain which has full access to the hardware, and to all the virtual machines on the host).
This is primarily on security grounds - you should, as a rule of thumb, only run essential services on the machines which carry the greatest value to you - if your Dom0 is compromised, all your DomUs (guest VMs) are also effectively compromised, as the attacker has access to the console of each VM.
If you do want to run some nameservers, and they're public-facing, and authoritative, there's no problem with running them as virtual machines, but you should make every effort to run them (you always need at least two) on entirely separate network segments to ensure availability.   For example:
ns1.redhat.com.        463 IN  A   184.108.40.206
ns2.redhat.com.        463 IN  A   220.127.116.11
ns3.redhat.com.        462 IN  A   18.104.22.168
Comment: +1 for not running anything other than minimum services on Dom0.


disable delete list item in list view

Question: i have a custom list with user who has only read permission goto the list view and select a item and press delete button in Keyboard then is Shows the below message and then when the user clicks ok then the message "Access denied" is displayed. How to Change this behaviour so that directly "Access denied" is displayed.
Comment: This is a OOTB SharePoint behavior. You cannot change it.
Answer: You could try to remove the check box from the list view so that user will not be able to select an item and delete it. modify current view, scroll to Tabular View => uncheck Allow individual item checkboxes => Save. This can prevent user delete row by delete key, but user cannot select multirow in table.
Or you could add a JavaScript in your list view page and we can disable the delete key, use the below code,
<code>$(document).keydown(function(e) {
var element = e.target.nodeName.toLowerCase();
    if (e.keyCode === 46) {
        return false;
    }
});
</script>
</code>
Answer: As Karthik's reply, we can disable the "Delete" key press using the code below in list view.
Add the code into a script editor web part in the list view to achieve it.
<code><script src="https://code.jquery.com/jquery-1.12.4.min.js" type="text/javascript"></script>
<script type="text/javascript">
SP.SOD.executeFunc("clienttemplates.js", "SPClientTemplates", function() {
    SPClientTemplates.TemplateManager.RegisterTemplateOverrides({
        OnPostRender: function(ctx) {
            $("table.ms-listviewtable tr").each(function (index, el) {
                el.addEventListener('keydown', function (event) {
                    if (event.which == 46) { event.stopPropagation(); }
                });
            });
        }
    });
});
</script>
</code>

disable delete list item in list view


Can't create template which includes site content

Question: I'm trying to create a site template which includes the content from the site but I keep getting an error and the template creation fails. The error is as follows:

Sorry, something went wrong
Microsoft.Workflow.Client.ActivityNotFoundException: The activity named 'WorkflowXaml_a6e17c88_46d6_4f20_bbf5_5a431fbe8636' from scope '/spo/56654289-5fe6-4a6e-9927-a95e37949fe4/34a8e849-276d-4463-87bb-8727d8627eb0/33095035-a88b-43d3-add8-ce14aa2398cc' was not found. HTTP headers received from the server - ActivityId: --------. NodeId: . Scope: . Client ActivityId : --------. ---> System.Net.WebException: The remote server returned an error

Any thoughts as to how I can avoid this error and create the site template with all the content included (content: 5 task lists, calendars, doc library with about 20 empty folders, and a few other apps)?
Answer: Delete the workflow on the lists before attempting to save as template.
Be careful though -- you will need to re-create the workflow (as a reusable workflow) so be sure you have it documented.


Why use logistic regression instead of SVM?

Question: I have a very basic question, but it's not really clear to me. When would one choose logistic regression over SVM? Maximum margin property seems more justifiable then whatever log. reg does. Is it because scores or interoperability?
Comment: "Whatever log(istic) reg(ression) does.", do you know, or are you just being flippant?
Answer: No technique is superior in every case (cf., the No Free Lunch Theorem). If your problem is amenable to logistic regression, why not use a method which tends to provide well-calibrated scores? SVMs don't, and in most of my work, well-calibrated scores are very useful.
Here's an interesting quote from Murphy (Machine Learning: A Probabilistic Perspective) that doesn't say that you would not want to use an SVM, but it does give you a perspective that alternatives (not necessarily logistic regression) are something worth considering:

Note that SVMs are very unnatural from a probabilistic point of view. First, they encode sparsity in the loss function rather than the prior. Second, they encode kernels by using an algorithmic trick, rather than being an explicit part of the model. Finally, SVMs do not result in probabilistic outputs, which causes various difficulties, especially in the multi-class classification setting.

(Personally, I was initially taken by SVMs, but when applying them to real-world problems have found them to be fiddly and slow.)
Comment: Fidgety?  Please elaborate.
Comment: @rolando2: Remember, this is a "Personally, I..." statement... SVMs have a variety of settings that I find over-sensitive and don't feel like I can adjust in a principled way. (And I'm not a fan of grid searches over parameter combinations.) They're not straightforward to tune, in my opinion, so perhaps "fiddly" is a better word.
Answer: SVM is a machine learning method, while logistic regression is a statistical one. There is a nice paper by Leo Breiman, where he compares what he calls "Data Modelling" (and what I call "statistics") to "Algorithmic Modelling" (i.e. machine learning).
Briefly, if you are interested in discovering why and how some variables affect other variables, and also want to know how credible the answers are, and if you can make some rather strong assumptions about your data (see my explanation on logistic function), then statistics is the way to go. On the other hand, if you just want to have someone tell you for your input data which output (response) to expect (perhaps because you have so many variables that you cannot even hope to make sense out of them), machine learning is the way to go.
For example, we know that men are, on average, taller than women, and that height is approximately normally distributed. If you were to guess the sex of an unknown person based only on his/her height, logistic regression is a reasonable thing to do.
If, on the other hand, you want to do face recognition, you'd probably want a machine learning algorithm, like SVM. We have no statistical theory about the distribution of pixels in face images and even if we had, you probably don't care which pixels influence classification in which way.
Comment: While I agree with you on the different applications of algorithms as per statistics vs machine learning, I disagree that logistic regression is not a machine learning algorithm. People think of logistic regression as statistics since it's been around since before machine learning was in vogue. If logistic regression were to just be discovered now no doubt we would refer to it as a machine learning algorithm.
Comment: I agree that the exact boundary is somewhat subjective. Some people consider even linear regression to be a machine learning algorithm. Seen that way, any statistical algorithm can be thought of as a machine learning algorithm. But I don't see how this helps clarity.


Flooring Options for Basement with Uneven Concrete Slab

Question: Working on a basement remodel and getting to the point of needing to figure out flooring. Unfortunately, the concrete slab is generally uneven. I had a company come in and grind the floors a few months ago. While they did a great job of making the floors WAAYYYY better than they were, the floor is still not flat enough for any type of floating floor installation like LVP. I bought a box of LVP from a local Floor and Decor to test out install on the uneven floor. The LVP does a decent job of conforming to the unevenness, but there are still some areas where you can notice the dips in the floor and the LVP will bow in these dips. This is less than ideal, so looking for some options or insight into what can be done for flooring. I put a bunch of ideas that I've had below, but wondering if the DIY forum has any additional brainstorm ideas.
LVP or any vinyl generally seems to be the preferred material due to its water resistance for a below grade application. Open to suggestion on this as well.
Options to Work Around Uneven Concrete Subfloor

Glue Down Vinyl - Find some glue down vinyl planks from companies like Flooret. Pros: Planks will conform to slab the best, most solid install method. Cons: Finish options are more limited.
LVP [Option 1] - Use regular LVP and glue this down to subfloor. Companies like Titebond make an moisture barrier adhesive for flooring, so seems like it could work. Pros: Lots of flooring choices. Cons: Will it actually work?

LVP [Option 2] - Use regular LVP and shim low spots as needed using floor patcher, shingles, etc. Pros: Lots of flooring choices. Cons: Giant PITA to shim everything. Cost for floor patcher, shims, etc.

Concrete Screeding - Use concrete to screed out the current slab and get rid of the remaining height variations. Pros: Get a nice flat subfloor. Cons: Very expensive $$$$, better for professionals.

Plywood Subfloor - Put down vapor barrier on slab, and place 3/4" plywood over . Seen a few other suggestions of using 2 - 1/2" plywood sheets and orient them 45 degrees off each other for stiffness, then screw together. Would probably still have some unevenness, but the plywood would ride over some of the imperfections better. Could secure the plywood to slab with Ramsets/Tapcons. Pros: Flatter subfloor than current, though not perfect. Cons: Some additional cost but DIY-able. Takes away from ceiling height, but 3/4" loss seems like a fair tradeoff.

Sleepers/Plywood Subfloor - Scribe some sleepers on the floor. Pros: Can get flat subfloor. Cons: Cost (plywood + PT lumber), time, takes away from ceiling height

Concrete Stain - Embrace the floor that's there and stain it. Use area rugs to cover up main areas. Problem is the current concrete isn't visually great. Would still require some patching (there is an old 1 inch wide trench from BX cable that used to run to an oil tank)

Epoxy Coat - Embrace the floor that's there and epoxy coat. Would require some concrete work to patch some holes/cracks. Pros: Embrace the floor that's there. Cons: Cold floor, epoxy isn't my favorite look, requires some additional work but not super hard/expensive. If you want a better looking floor, may need pro install.

Additional notes:

There is a general slope to the floor where it drops about 3 inches
over a length of 30ft. (house is 100+ years old). I could use
self-leveling compounds to make this up and get the floor level &
flat, but that would just be a huge cost to do this.
Ceiling height is limited. Current ceiling height is 7ft, just
meeting code reqs. Any solutions that add height to floor I am less
inclined to look at.
Basement is very dry. Its mainly above grade except for the back wall
(house is built into hillside). Also had a french drain installed so
any water that happens to get through is drained out through front of
house.
Comment: These are all viable options. Unfortunately, picking one over another is a matter of opinion, and that's off topic.
Comment: I used your action plan list point 6 in my basement, only flooring/patch the areas by usage.
Comment: @FreeMan had a more in depth discussion with an applications person at Flooret. He mentioned that their adhesive they sell is pretty aggressive. Even though they specify in their info pamphlets that the flooring spec is flatness within 3/16" or better, he said they've worked with installs with wavy floors. The adhesive does a good job of making the boards conform to the substrate. That also may just be marketing talk, so taking it with a grain of salt. But if true, this seems like the best option.
Answer: Another option:
Self levelling low-spots only, and optionally adding plywood to smoothen the rest.
"self levelling" cement is not liquid as you think and you can apply it in patches without worrying that it will run like water. You have some troweling time to work low areas as large as say 5x5 ft.


Altium doesn't show any violation

Question: My Altium Designer does not show any violation, even if I place 2 components right above each other.
Im quite the beginner at PCB Design, but does someone know the answer to my problem?
Comment: what about your rules ? Are your clearance rules set ?
I believe they are Design >  Rules > Electrical > Clearance

And then the general clearance or something, if you set the SMD pad to SMD pad to the desired clearance between pads you want, do you get  the clearance errors?
Comment: What if you run a Design Rule Check ? (hotkey T > D)?
Comment: Only Unrouted Nets
Comment: Can you check the Electrical Clearance in your design rules: (Design - Rules)
Comment: Nevermind i fixed it, it had something to do with my preferences, I set it to defaults and it worked again. Now i can see my wonderful green errors :)
Answer: You can set the clearance to Min 0.254 and also ensure DRC rule check is ON to show the Violation.
Answer: If you expect this to happen as soon as you create a violation, then the malfunction could be because the online DRC was turned off. It slows down the tool a bit, but on small designs/fast machines it's not a problem.
Alternatively you could use the manual DRC check, which is good practice to run after schematic chances and once you want to check the status of your PCB design.
Above all, it's important to set up good design rules for your manufacturing technology. Check at your PCB manufacturer which widths/clearances they allow, such you can design for that. If you don't know how all of this works, it's best to work with the defaults and do not delete any rule.
The design rules are there not to annoy you, but as a check that the board can be manufactured and is free of obvious mistakes. However, in my personal opinion, for hobby boards/very quick prototypes I would mostly ignore the silkscreen errors as I only really care about the copper and solder mask in those cases.

Altium doesn't show any violation


ROOTING THE ANDROID DEVICE

Question: Hope y'all doing fine, My question may be so lame sorry but wanted to know the answer.. how to root a android device I have mobile of Sony Ericsson Xperia Mini (ST15i) I bought that before 3 years, still use the thing it's still good working condition but on the latest update of the software which it sucked all my internal memory now i have only 100 MB to usable and latest update of Facebook alone is 25 MB + extra data 30 + cache 10 MB and total is 65 MB (rough calculation) so thought of removing the unwanted default apps which came with the update which were uninstallable searched for removing, XDA Developers  said that the best bid is to root our device and so can you guys please guide me how to root I checked with SuperOneClick it never worked
Answer: So, here I will be trying to help you real fast by directly dropping you over to the thread over stack exchange How to root the Xperia Mini ST15i.
PS: Updated the link.
Comment: bro downloadable files which has root tool kit have been removed.. :(
Comment: Oops I think I may have to check it before giving it to you ! @rajesh now try looking over the post I have updated the post.

ROOTING THE ANDROID DEVICE


How to access a DLL file in java?

Question: I have some methods in a Visual Basic 6.0 DLL that I need to access in Java 6.0. How do I do this?
Answer: The Java Native interface is your friend. But the easier way should be using the Java Native Access library. Here's an answer to a similiar question.
Answer: JNI can be easily used to access any function publicly available in a DLL (managed or unmanaged) so that it can be used in java.
You will need to create your own interface, using Java Native Interface (JNI), and then call the interface functions as you normally do.

How to access a DLL file in java?


Attach 15-inch Macbook pro screen (with broken logic board) to 21-inch iMac (with broken screen)?

Question: I am curious to know if I can take the screen from my Macbook Pro (15-inch, 2010) and somehow use it as a display for an iMac (21-inch, 2012) either through a direct connection to the logic board's display pins or via the mini display port.  The logic board is dead on the laptop and the screen is dead on the desktop, so between them, maybe I can have one functional computer.
Comment: I'd suggest that you're best off buying a new monitor and plugging that into the iMac.
Answer: No. The internal connectors are incompatible between the two; different size and different pin-outs. And there is no functional way to route the display signal through the mini Displayport from one to the other.
Answer:
I am curious to know if I can take the screen from my MacBook Pro (15-inch, 2010) and somehow use it as a display for an iMac (21-inch, 2012) either through a direct connection to the logic board's display pins or via the mini display port.

Yes, you can.  However, it's not a direct connection or a simple case of getting an LVDS cable long enough to go from the logic board on the iMac to the 15" display.
You need a LCD Controller Board specific to that LCD panel.  There are a lot of DIY instructions on how to do this very thing, but to summariaze, here's what you'll need:

The exact model of the LCD panel (you'll have to dissasemble the display) because you'll need the model number and connector info it when ordering the LCD controller board and cables

The LCD controller board itself.

HDMI or DisplayPort (or both).
LVDS cable(s)
Inverter board (if necessary).  Depends on if you have an LED or CCFL display

Some sort of housing or stand for your display.

If you're going to do this, you'll likely have to custom build an enclosure for your screen - likely in a form factor of a picture frame or shadow box because you'll need somewhere to mount both the panel and the controller board as well as have a sturdy place to mount the control buttons (i.e. power button) and cut outs for your display inputs (HDMI, DisplayPort, VGA, etc.)  I also recommend going with DisplayPort as you won't need an adapter to go from the DisplayPort out from the iMac.
Is this worth it?
No.  You're better off finding used display panels for both machines.  In fact, it's cheaper to buy a low spec monitor for the MacBook Pro and use that as a desktop in closed clam shell mode.  The displays for the 21" Late 2012 iMac can still be found on eBay or you can part out the machine as it has excellent salvage value.
I recommend repurposing displays only if you have a custom application like a Raspberry Pi project or similar.  The cost and effort is much more than what you can source replacement parts for.
Comment: Despite the fact that this solution is neither cost or time-effective, it sounds fun to me.  Thanks!


From Gentoo to ubuntu

Question: I would like to move from Gentoo to ubuntu. Is there the possibility to change without pain? I have lot of data and no way to backup it! Any hint?
I have a latitude e6400, which version of ubuntu should I install?
Thanks in advance
Comment: Change without pain ? Well, you might have to fiddle a bit with your video drivers but for the rest it should be quite painless. What drivers are you currently using for video ?
Comment: nvidia (the closed one)
Comment: Hard to make any constructive comments without even a list of partitions ... ;) maybe add that. RAM available?
Answer: I persume you have your valuable data on a seperate (/home) partition ?
In that case you can migrate without pain.
The ubuntu installer will let you do the partitioning if that is your preference so you are in control which partition must be home or which partition is to be left alone.
At the moment I prefer the Ubuntu 12.04 LTS version (13.10 is to me a bit too buggy/unstable but that is only my personal opinion, in other words: your milage may vary)
Considering your driver preference: Ubuntu has the closed source drivers in the standard repository which can be automagically installed and configured from within it's settings icon (found in the launcher bar).
For the rest is the driver support good to top-notch. I would say, give it a go.
Comment: actually I have all in /, that`s my pain. Any simple solution?
Comment: oops! That is painful indeed. There is no simple solution other than making a backup. The not-so-simple solution is to shrink your partition first with "gparted" to make space for what will be your root partition. This is, however, not completely without danger. Also resizing, however automatic, really could take some time.

From Gentoo to ubuntu


How can I return an array of integers from Solana rust program function to front end?

Question: I don't know how can I write an onchain program in Solana that after executing the logic, returns an array of integers, strings, etc ... to the client, and how can I fetch it using web3?
Answer: Solana instruction handlers don't return data, they write to accounts and return a rust OK (showing the instruction has completed successfully).
So store the integers or string in an account. Then use the web3 library to read the contents of the account (this is easier when you use Anchor)
In Rust(Using Anchor)
<code>pub struct StoreStuffInAccount<'info>
{
// The necessary accounts needed to store data on the Blockchain

    #[account(mut)]
    pub payer: Signer<'info>,// account that pays transaction fees

    #[account(init, payer = user, space = 8 + 4 + 32 + 4 + 32 + 1)]// space represents size in bytes you want to store on the blockchain
    pub stuff_account: Account<'info, Stuff>,

    pub system_program: Program<'info, System>,
}

pub struct Stuff
{
  // The data(String, Integer) you plan to store on the Blockchain
   firstname: String,//32 bytes
   lastname: String,// 32 bytes
   birthday: u8, // 1 byte
}

pub fn store_stuff_in_account(ctx: Context<StoreStuffInAccount>, first_name: String, last_name: String, birthday: u8) -> Result<()>
{
// This tells the smart contract to store information on the blockchain
  let stuff = &mut ctx.accounts.stuff_account;

  stuff.firstname = first_name;
  stuff.lastname = last_name;
  stuff.birthday = birthday;
  Ok(())
}
</code>
You can learn more about the space calculation
In Client Side
<code>  import * as anchor from "@project-serum/anchor";
  anchor.setProvider(anchor.AnchorProvider.env());
  const provider =  anchor.getProvider() as anchor.AnchorProvider;// local wallet for testing
  const program = anchor.workspace.StoreStuff as Program<StoreStuff>;// the deployed smart contract information exists here including address
  const stuffAccount = anchor.web3.Keypair.generate();// Create a new Account that we will use to store information

      await program.initialize("first_name", "last_name", "24092022" ) // calls the smart contract to store information on the blockchain
        .accounts({
        {
          payer: provider.wallet.publicKey,
          stuffAccount: stuffAccount.publicKey,
          systemProgram: SystemProgram.programId
        })
        .signers: [stuffAccount]
        .rpc()

// Retrieve an account from the blockchain so that you can read its contents(anchor deserializes it for you)
      const account = await program.account.stuffAccount.fetch(stuffAccount.publicKey);
      console.log("firstname ", account.firstName);
      console.log("lastname ", account.lastName);
      console.log("birthday ", account.birthday);
</code>
To learn more on how on how to start writing smart contracts on solana. You can start from here
Answer: There's a syscall available to on-chain programs called set_return_data, which puts data into a buffer that can be read by the higher-level programs using get_return_data. This all mediated through opaque byte buffers, so you'll need to know how to decode the response.
If you want to fetch the data from the client side, you can simulate the transaction and read the data back from the return_data field in the response: https://edge.docs.solana.com/developing/clients/jsonrpc-api#results-50
The RPC support in simulated transactions is very new in version 1.11, but the return data is available in earlier versions.
Source code for set_return_data at https://github.com/solana-labs/solana/blob/658752cda710cb358d7ccbbc2cee06bf8009c2d4/sdk/program/src/program.rs#L102
Source code for get_return_data at https://github.com/solana-labs/solana/blob/658752cda710cb358d7ccbbc2cee06bf8009c2d4/sdk/program/src/program.rs#L117


Should I say soccer game or soccer match?

Question: Which is the more correct: soccer game or soccer match? Are they both equally valid?
Comment: Football match! Not that I like football, but still.
Comment: @Cerberus *Soccer* seems to have been accepted in Britain until the 1980s or so, when, ironically, the rising popularity of the sport in the U.S. led *soccer* to be labeled as an American usage and thus an affront.
Comment: @Cerberus Antipus, please.  Don't you understand Greek singulars?
Comment: @DavidWallace: What? Mormons use *antipus*? By the way: 1398 Trevisa Barth. De P.R. xv. lii. (1495) 506 *Yonde in Ethiopia ben the Antipodes, men that haue theyr fete ayenst our fete.*
Comment: Soccer teams play matches.
Comment: @Cerberus you are a trouble-maker.  And wrong.
Comment: @DavidWallace: At least I'm not an antipode! How have you been??
Comment: @DavidWallace: You know, I seriously searched for *antipus* in the dictionary, hoping it would exist. But it didn't so, I had to use *antipode*. My apologies.
Comment: @Cerberus Well, YOU are clearly not a Mormon then.
Comment: Haha!  It was actually suggested to me a while ago that I should live in Ethiopia.  @Cerberus
Comment: @DavidWallace: And now you have learned that you already live there. Why Aethiopia, by the way?
Answer: Note that in some sports, notably tennis, there is a division in which "match" occupies a higher place. For instance in tennis, the players engage in a match, which consists of multiple sets, which consist of games.
Game and match mean the same thing when this hierarchy doesn't apply: when a single game is considered to be a match.
Which one is used depends on the region: both the region where the sport originates, and the region from which the speaker comes from who describes it as either a game or match. One-game-match sports from Britain tend to attract the "match" terminology.
See also: https://english.stackexchange.com/questions/34105/what-determines-whether-a-sporting-event-is-a-game-match-contest-or-something
Answer: Something of a generalization, but if you're calling it soccer then you're most likely in the USA, or a place whose English is influenced by American English (since the USA is by far the most populous English-speaking region in which "football" means something else). So team sporting events are generally called "games", soccer included. But MLS does use "match" at least sometimes, so I suspect US soccer fans do likewise sometimes.
If you're speaking British English then formally it's pretty much always a "match", even if for some reason you're calling it "soccer" rather than "football". Football itself is "a game" ("the game of football", "the beautiful game"), but a particular fixture is "a match" ("did you see the match?", "I'm going to the match").
The word "game" is also used when talking about the event in a less formal way ("he had a great game") and for variety. Quoting a BBC news report that I'm watching that just reminded me of this question: "A capacity of 79 thousand people will be in there, watching the game, but around the world would you believe something like a billion people all over the planet will watch this match on television".
By the way, it's not exactly incorrect to call it "soccer" in British English (AFAIK the term was coined in England meaning "asSOCiation football", as distinct from rugby football). But it's unnecessary to specify, and "football" is preferred by almost everyone. Calling it "soccer" suggests that you refer to something else as just "football", which means you're either some kind of foreigner or really devoted to rugby.
I don't know what happens in Australia, where "soccer" would often be used to distinguish from Aussie rules football. If I had to guess, they would call it a "soccer match" there.
Comment: I agree with your game/match distinction in British English, but people do, in my experience, sometimes also talk about "playing a game of football". To me, at least, "a football game" suggests something slightly more informal than "a football match".  A game might just be a bunch of friends in the park on a Saturday morning but a match would probably be part of a league or other formal competition.
Comment: @DavidRicherby: good point, that matches my experience too. A "match" suggests a formal fixture. "Formal" isn't necessarily under FA auspices, but held between named teams where the result might be recorded. Annual staff vs. managers could probably just about qualify as a match, but could also be called merely a game.
Comment: "Soccer" was indeed coined in England ([in Oxford, to be specific](https://en.wikipedia.org/wiki/Oxford_%22-er%22)) and might well be used to distinguish soccer from rugger (rugby football).
Comment: The name soccer is used anywhere where (a) another football code is popular and (b) that football code is commonly called football. So in NZ, Rugby football is popular, but it's always called rugby, not football, so Association football is still called football there. However, Gaelic football is popular in Ireland, and though it's often just called "Gaelic", it's called "football" often enough that we call Assn fball "soccer". Ditto Australia (Aussie Rules), USA (Am Football), and Canada (Canadian Rules Football).
Comment: Just for reference, the word "Rugby" is a place name, not the name of a sport.  Football was played at Rugby School as early as the 1750s.  Soccer was invented in 1863.
Comment: @TriG Until about 15 years ago, the word "football" in New Zealand exclusively meant Rugby football.  Then the soccer body here launched a huge campaign to  have _their_ sport known as "football".  It was largely successful.  So now, older people tend to use the word "football" to mean Rugby football, and younger people tend to use it to mean soccer.  Your "always called rugby" assertion is therefore incorrect.
Comment: @David: I suppose in some sense you're right that "rugby" isn't the name of a sport, arguably it's a hypernym of two sports. But they prefer to consider themselves different "codes" rather than different sports :-)
Comment: Match = we are looking for a winner. Game = we are just playing.
Answer: Either is valid, although I'm sure you will notice regional differences as to which is used. In the Midwest of the US, I almost always hear game rather than match.
Comment: Also on the West Coast, I usually hear game, not match (other than tennis, golf or other non-team sports).
Answer: I think that match is used in sports in general like in wrestling (no game), but game is more like with friends or with sports with several players. Also note that the FIFA games use match like the official page.but at the end they are equally intercheable.
Answer: For what it's worth, FIFA's Laws of the Games, Law 7 refers to 'The Duration of the Match'.
Comment: This is pertinent, but doesn't really answer the question and would be better as a comment.
Comment: Law 1: "A match is played between two sides, each of eleven players, one of whom shall be captain."
Answer: Game or match? This depends on what you mean. I hope this adds a bit on your understanding of the two words...
When you say game, it could mean the game itself, not necessarily played, being played or about to be played. It is simply the sports with the rules/regulations/etc.
When you say match, it means a game that was played, being played or about to be played by competing teams.
Examples:

I love playing the soccer game in my PS Vita. - The game itself
I love the soccer match between the X and the Y in my PS Vita. - Here the game was played
The soccer game was played by the X and the Y. - Here the game was played so now you could say it is a match.
The soccer match between the two teams was great! - Again, this means the game was played


Process Builder running 2 versions with a time based Create Action?

Question: I revised the initial process to include few more fields on a time based create action. Now I have 2 records being created the same time and only 1 Process is active. What could be wrong here? Is there a way to reset the Process Builder scheduled Create Action?
Answer: Under WorkFlows and Approval > Flows > All scheduled Proccess Builder will be listed. Create a new view add the filter you need see what version of what Process Builder is be used and Start Deleting.


If $f(g) = g^k$ is a homomorphism on a finite group $G$ and $k < |G|$ does not divide $|G|$, must $G$ be abelian?

Question: There was a question that asked to prove that if $f(g) = g^3$ is a homomorphism on a finite group $G$ and $3$ does not divide $|G|$, then $G$ is abelian. Does this extend to any $k < |G|$ where $k$ does not divide $|G|$, instead of just the case $k = 3$? I.e. if $f(g) = g^k$ is a homomorphism and $k < |G|$ does not divide $|G|$, is $G$ abelian? If not, what is a counterexample?
Comment: Does this answer your question? [$|G|=p^3$. Prove that $\phi(x)=x^p$ is a homomorphism](https://math.stackexchange.com/questions/964859/g-p3-prove-that-phix-xp-is-a-homomorphism)
Answer: No, the Quaternion group $Q$ of order $8$ is non-abelian, but the fifth power map is a homomorphism $Q\to Q$ (the identity).
Answer: Consider a non-abelian $p$-group of exponent $p$, with $p$ an odd prime. For instance the group of order $p^{3}$ and exponent $p$ will do.
Then
$$
(ab)^{p+1} = (ab)^{p} a b = a b = a^{p} a b^{p} b =  a^{p+1} b^{p+1}.
$$

In general, if $G$ is any finite group of exponent $e < \lvert G \rvert$, then $k = e+1$ should do. See for instance the example by James.
Comment: Obvious follow-up question: if $x\mapsto x^k$ is an automorphism of $G$ then does $k\equiv1\bmod(\exp G)$.
Comment: @whacka, good question, I don't have an answer right now. You have any ideas?
Comment: @whacka, no, wait, I do have an example in which $k \not\equiv 1 \pmod{\exp(G)}$. Take an odd prime $p$, and let $G$ be the nonabelian group of order $p^{3}$ and exponent $p^{2}$. Then $x \mapsto x^{p+1}$ is an automorphism, as $(xy)^{p+1} = x^{p+1} y^{p+1} [y, x]^{\binom{p+1}{2}} = x^{p+1} y^{p+1}$. We have used the fact that $G'$ has order $p$, and that $p$ divides $\binom{p+1}{2}$. But I think your conjecture can be refined, at least for the case of finite $p$-groups, for instance to something like $k \equiv 1 \pmod{\exp(G')}$.
Answer: We have $(xyx^{-1})^3 = x^3y^3x^{-3}$ by that homomorphism. By writing out the product we get $xy^3x^{-1} = x^3y^3x^{-3}$. Therefore, $y^3x^2 = x^2y^3$. Since the $3$ does the divide the order of $|G|$, every element in $G$ is a cube. Therefore, the squares commute with $G$. Now write $(ab)^3 = a^3b^3$, expand, and commute the squares, and you get $ab=ba$.
Now if we try to do is more generally, if $k$ does not divide $|G|$, then the claim that every element of $G$ is a $k$-th power does not generalize. Unless we know that $k$ is a prime. But even if $k$ is a prime and does not divide $|G|$, then I am not sure how to conclude that it is abelian. For example, if $k=5$, then we reach $(b^3a^3) = (ab)^3$, and not sure if this is enough anymore.


Is there a way to reassign drones in batch or automatically?

Question: Let's say I ordered from Earth 100 drones and I want to dispatch all of them through many different Drone Hubs. Do I have to click on each of them and reassign one by one individually? Is there a way to reassign drones in batch or automatically?
Answer: A quicker way than the other solutions currently here:

Select the drone hub that you want to assign from
Click "Dismantle drone" - this will turn the drone into a drone prefab. Repeat until you've disassembled the number of drones that you want to move.
Select the drone hub that you want to assign to.
Click "Construct drone" to recreate all of your disassembled drones.
Answer: As of 19.03.2018 - No, there is no way to mass-assign drones. Manuel Clicking is required.
Sadly there is still not even a mod for it.
100 is a rather huge amount. But when I get around ~10'ish my favorite way to assign them is this:

Pause game
Select Rocket.
Click drone
assign to quickbar
repeat 2~4 till all drones are on the bar
Go to Dronehub
use quickbar to select drone
assign to hub
remove from quickbar
repeat 7~9 till done

I believe this list shows that this is a serious flaw and will hopefully be fixed soon.
Answer:
Left click on drone hub, RC drone, or Rocket. All drones assigned to it will be shown.
Left click on the drone you want to reassign.
Right click on hub, RC drone, or Rocket you want them assigned to.
Depending on drone slot availability, it will be reassigned..

Quick.
Answer: A very simple trick I just discovered is the following:

Land the Rocket filled with drones near a Drone Hub
Wait for the drones to leave the Rocket and idle
Launch the Rocket back to Earth after it fully refuels

This should auto-assign all drones to the nearest Drone Hub.
Hope this helps!
Answer: I've noticed that you can just launch the rocket and all the drones will be spread among drone hubs in range. Then from drone hubs the easiest way to reassign is to deconstruct drones at one hub and reconstructing them at another.
Answer: Finally, here is my fastest method.
For each drone:

Add a hub to quick bar
Click drone
Click "Assign"
Right click on the Hub in the bar


Why does the thermal equilibrium change so quickly?

Question: I performed an experiment recently where I tested the specific heat capacity of different metals in water. Once the metals were removed from a beaker and placed into calorimeter with water, thermal equilibrium occurred very quickly. Why is it that thermal equilibrium is achieved so quick when a calorimeter is used?
Comment: I should add that if you repeat the experiment with non metals, they should have the same mass and same shape to the degree possible given the differences in densities.
Answer: Its because you were testing metals. They have high thermal conductivity and hence heat transfers through them quickly to the water. Try the experiment with non-metals, e.g., plastics. You'll find it takes longer to reach thermal equilibrium.
Hope this helps


Fluid exerting buoyant force on itself?

Question: I was just wondering, if I took some infinitesimal section of a fluid and constructed a free body diagram on it, would it experience a buoyant force from the rest of the fluid it is part of to cancel out its weight? And how does air pressure play a role in this situation?
Comment: You're spot in in your reasoning. Indeed you'll find that the weight of the isolated fluid gives rise to the pressure gradient that leads to buoyancy. See my answer here for more details: http://physics.stackexchange.com/a/274101/26076
Answer: To the first question: yes, formally. Keep in mind that small currents and diffusion means that the fluid will still mix, regardless of whether it's gas or liquid.
To the second question: the role air pressure plays is to set the pressure at the surface of the liquid. You should think of the buoyant force as being less about pressure, though, and more about the rate of change in pressure. The reason you experience a noticeable buoyant force underwater is because the pressure is changing with the depth linearly, producing a constant force, and your density is about the same as water's. Out in the air you also experience a buoyant force, but it's much smaller because the rate at which the pressure drops is much slower because air is about one thousand times less dense than water.
Answer: Your infinitesimal section of fluid is in static equilibrium and so the net force on it must be zero.
The section has a weight and therefore must have an equal in magnitude but opposite in direction force on it which is the upthrust produced by the rest of the fluid.
Replace your section with an object which has less weight (less dense) than your section and the net force will be upwards - air bubble in water, more weight (more dense) and the net force will be downwards - sand grain in water.
Air pressure has no effect as the upthrust depends on pressure differences unless your fluid is compressible.
A higher air pressure would compress the fluid making it more dense and so increase the upthrust.
For a liquid which is virtually incompressible this effect would be very small but for air below air (our atmosphere) the effect is significant.

Fluid exerting buoyant force on itself?


Will VB.NET automatically generate ComClass attribute and guids?

Question: I've run across some VB.NET code that explicitly creates three GUID constants and uses them in a class's ComClass attribute. I've written COM-aware classes in the past just by checking the "Make COM-Visible" and "Register for COM interop" options in the project options. Is this explicit code simply unnecessary, or is it doing something above-and-beyond what those two options do? Here's a snippet:
<code><ComClass(MenuHandler.ClassId, MenuHandler.InterfaceId, MenuHandler.EventsId)> _
Public Class MenuHandler
    Public Const ClassId As String = "A2204623-A902-44d4-B524-FDFFCD176E53"
    Public Const InterfaceId As String = "3449CA8B-16DF-4a61-8BAB-DFF27AE70F5E"
    Public Const EventsId As String = "06C156DD-0ABA-437e-9EE0-C1CE2CA34033"
End Class
</code>
Answer: The ComClass attribute is specific to Visual Basic and is intended to simplify the creation of COM objects in .Net code.  When the compiler sees this attribute it do some of the tedious work under the hood that must be manually done in C#.  In summary, it's a shortcut for Visual Basic Code for creating COM objects.
Here's a great article on what this provides over doing the same in C#:

http://codebetter.com/blogs/peter.van.ooijen/archive/2005/08/02/130157.aspx
Answer: By explicitly putting attributes on the classes and enumerations that you want exposed you can prevent things like helper classes, internal tools, or internal classes that should not be exposed from being exposed.  This is the recommended way from Microsoft to do it...and when they recommend something, it usually means that if you don't do it, your program may break in the future.  :)
Checking "make COM visible" and "register for COM interop" is the simple method for making COM visible objects, but is not recommended.  This will add the overhead for every class visible - even ones that you may not want.
Answer:
Will VB.NET automatically generate ComClass attribute and guids?

Yes, if you use VB.NET COMClass template to create a class, COMClassAttribute and those GUIDs will be automatically generated.
Detail in MSDN
Section "To create a COM object by using the COM class template"


Introductory book for group theory: recommendations

Question: I am interested in learning the basics of group theory. I know a few basic theorems like Lagrange, Cauchy etc., but nothing from group actions. What would you recommend?
Comment: "Abel's Theorem in Problems and Solutions", part 1.
Answer: Mathematicians generally fall into two broad categories of intellectual style:  geometers and algebraicists.  (The greatest mathematicians spanned both styles.)  Those of us geometers prefer to think visually and spatially, while algebraicists prefer symbols and formalism.  Some branches of mathematics are best approached by one or the other of these cognitive styles, e.g., Number theory for the algebraicists, and Differential geometry for the geometers.
Group theory is an interesting branch of mathematics in which both styles can thrive.  If you're like me (a geometer), then by far the best book on group theory is:  Visual Group Theory by Nathan Carter.
I'll let an algebraicist suggest a book favoring that cognitive style.


Whats the safest way to remove lazy initialization proxies generated by Hibernate?

Question: I would like to keep the Parent/Child relationship but when I parse through the Parent Object I don't want to fetch the child elements.
Answer: Proxies are generated so that Hibernate can intercept calls to uninitialized associations and try fetching them on-demand.
The LazyInitializationException is a code smell. You get it because you haven't properly initialized all the required entity associations prior to closing a Session. Switching to EAGER associations is also a bad idea because the fetching policy is a query responsibility.
Try to reduce the number of associations if you don't need them and use queries instead. You can build an application with just many-to-one associations (mirroring the FK relations) and instead of one-to-many associations you can have DAO methods.
As for this statement:

I would like to keep the Parent/Child relationship but when I parse
  through the Parent Object I don't want to fetch the child elements.

If you keep the Parent/Child relationship you always need to load the association prior to using it. Trying to remove the proxies sounds like you are trying to hack a solution instead of properly design your application layers.
So Proxies are fine and they allow you to improve the application performance, because you don't always fetch all associations when you try to access a root entity.
To disable proxies you just have to annotate your entities with the Proxy annotation:
@Proxy(lazy=false)

Comment: 1st of all thanks.. Here is my concern... You said "instead of one-to-many associations you can have DAO methods" . Without one to many associations , I won't be able to use explicit joins for complex queries....  With One to Many association, Lazy Initialization, we are parsing the whole object using Jax-B, the child element will be accessed and it will be fetched.. which is unnecessary & performance loss. Also @Proxy(lazy=false) is not bringing the proxies but it is fetching all the child element.. which is again unnecessary & performance loss....Let me know if you have any suggestion.
Comment: Well, fetching entities makes sense when you plan to modify them. In your case a projection is more appropriate and will always perform better. You can write a portable natie query and you can fetch just the data you need for your use case.
Comment: You are actually right... The only option I have is Native query.. but again we have a weird requirement of doing pagination. Pagination will fail when a parent has many children's and we use native query to fetch some elements in parent and some in children's.. Anyway Thanks Really appreciate it....
Comment: can i disable lazy initializing only for one method?
Comment: Yes, you can. Use `JOIN FETCH` on the `FeatType.EAGER` association, and you'll fetch it using that query.


Expanding items?

Question: Is it true items expand in the air (items = lotion, shampoo, conditioner, sunscreen, perfume, etc)? If so how much room should I leave for certain products?
Answer: Yes, in principle these products expand. This happens due to the lower air pressure at high altitudes (which means there's less force squashing them together, so they can spread themselves out a bit more). Airliners and other passenger planes operating at high altitude are pressurised, but typically only to air pressures typically found about 6000-8000ft (around 2-2.5km) above sea level.
You don't need to take any special precautions for this. Typical bottles used for shampoo, perfume, lotion, etc, are perfectly capable of resisting the pressure difference and holding the product in without significant expansion. If you're carrying shampoo, toothpaste, etc, it's probably wise to pack them within a (preferably sealable) bag, to make sure they don't get all over your clothes if they do get out. But as long as you close the lids, that's more likely to happen as a result of something falling on and squashing them than it is to happen due to air pressure.
Comment: It's also only the air in those bottles or tubes, that expands significantly. The liquids don't expand that much. Since there is usually not much air in those containers (esp. if they are full) the expansion is also relatively small.

Expanding items?


truthy and falsey values

Question: What are the rules for determining if an object is truthy/falsey in Scala? I've found many for other languages like Ruby, JavaScript, etc. but can't seem to find an authoritative list for Scala.
Comment: I'm not sure I understand what you mean.  Only `Boolean` contains truth values.  Numbers, null, empty strings, etc. etc. etc. all are not `Boolean`.
Answer: No data type in Scala coerces to Boolean.
So... true is truthy, and false is falsey. No other values can be used as booleans.
It can't get simpler than that.
Comment: Wellll, this being Scala, you can coerce things yourself: `implicit def intsAreBooleanHaHaHa(i: Int) = if (i==0) false else true`.  Not that it's a good idea.
Answer: I don't know why no one answered this before. @Aaron was right, but his answer out of the OP scope.
You can have all values coercing to boolean with implicit conversions like:
implicit def toBoolean(e: Int) = e != 0
implicit def toBoolean(e: String) = e != null && e != "false" && e != ""
  ...

But you can even have something better. To make types behave like javascript for your own types:
trait BooleanLike[T] {
  def isTrue(e: T): Boolean
}
implicit object IntBooleanLike extends BooleanLike[Int] {
  def isTrue(e: Int) = e != 0
}
implicit object StringBooleanLike extends BooleanLike[String] {
  def isTrue(e: String) = e != null && e != ""
}

implicit class RichBooleanLike[T : BooleanLike](e: T) {
  def ||[U >: T](other: =>U): U = if(implicitly[BooleanLike[T]].isTrue(e)) e else other
  def &&(other: =>T): T = if(implicitly[BooleanLike[T]].isTrue(e)) other else e
}

Now you can try it in the REPL, it really becomes like Javascript.
> 5 || 2
res0: Int = 5
> 0 || 2
res1: Int = 2
> 2 && 6
res1: Int = 6
> "" || "other string"
res2: String = "other string"
> val a: String = null; a || "other string"
a: String = null
res3: String = other string

This is why I love Scala.
Comment: This is one of the more delightfully evil things I have seen.
Comment: What version of Scala are you using? When I try `5 || 2` in the Scala REPL in version 2.11.6, I get `:8: error: value || is not a member of Int`.
Comment: Nevermind, I read your answer more thoroughly and realized that you added implicit conversions that allow things like `5 || 2` to work.
Answer: You're not finding it because no equivalent concept exists in Scala, although you can define something similar for yourself (and libraries such as Scalaz do just that). For example,
class Zero[T](v: T)

object Zero {
  implicit object EmptyString extends Zero("")
  implicit object NotANumber extends Zero(Double.NaN)
  implicit def none[T]: Zero[Option[T]] = new Zero(None)
}

truthy and falsey values


DNS settings for domain controller with dual nics one facing internet directly and one to router

Question:
I have a server with 2 NICs. One of them is connected directly to the internet (it's on public IP)
The other NIC has a private IP and connects to our router which is connected to the internet also (different public IP)
Now, this server has been setup to be a domain controller and has the DNS role on it.

I noticed that after the DNS role was activated, both NIC DNS setting were changed to 127.0.0.1.
That server's routing table (route -4 print) shows EQUAL metric to both NICs.
The DNS role once activated is in its default settings
Does each NIC having DNS set to localhost could cause any problem ? What I wanted ideally is only the NIC with the private IP to have 127.0.0.1 as its DNS server IP ?
The other NIC is only a way to get inside that network should the router fail somehow.
Comment: Having a dual-homed DC, particularly with one NIC being public, is a textbook case of a bad scenario. You can probably do things to make this work, but I'm just not feeling up to researching it for you at this time :-) My advice, which is not an answer, is to *NOT* do this at all and redesign your network so that your DC is not public and not dual-homed.
Answer: ACTUAL ANSWER:
Your DNS server needs to be authoritative for your local domain. Set the "router" NIC to use itself as its DNS server (ie. its internal IP, not localhost). You also didn't mention setting up DNS forwarders, so make sure you do that or your users will complain that "the Internet is down." This really means that your DNS server is not forwarding their DNS requests to the next appropriate DNS server in the chain.
FRIENDLY ADVICE:
With that out of the way, I'm seconding the concerns with a web-facing domain controller. This is an immensely bad idea, and this is not how you perform out of band access. Your domain controller is the inner keep of your castle (network), and you must protect it appropriately. Never expose it to the Internet, for any reason. Do not forward ports to it. It should be completely impossible to route to it from the Internet. If I can ping your domain controller, you are doing something wrong. Is the message clear yet? This is not negotiable!
If you want out of band access on a shoestring budget, set up a workstation or similar in the same position as where you were going to put your domain controller. Add the second NIC, then harden the living daylights out of it. Add firewall restrictions to allow only a handful of known IPs, like your house, and keep it patched. Good luck.
Comment: "If I can ping your domain controller, you are doing something wrong."... couldn't have said it any better.
Comment: @AdrianGrigore Set up a VPN. Ping does not make things insecure, lack of ping does not make them magically secure. You need a dedicated machine to be a firewall because of separation of concerns: https://en.wikipedia.org/wiki/Separation_of_concerns. Please reconsider what you're doing.
Comment: What if the DC is secured by it's own firewall, but only allows inbound traffic for my own static ip's? You could not ping to it, so IMO it should be secure. Why do I need a dedicated machine just as a firewall?
Answer: TL;DR: Don't multihome a DC, don't put a DC on a publicly accessible IP address, don't do both things at the same time. But if you still want to do these things, at least be sure you really know what you are doing.

As others have said, do not put a domain controller on a public IP address without a firewall protecting it. And even with a firewall protecting it. "Just Don't Do It". (TM)
As others have said, too, do not multihome a domain controller unless you really know what you are doing. (And, if you really know what you are doing, you'd usually try any means to avoid it.)
If you really, really, really need a dual-homed domain controller, or any dual-homed Windows server, don't put a default gateway in each NIC's configuration. Windows is not going to load balance two Internet connections, and will even warn you that two default gateways are not supported. Set the default gateway only on the NIC that will be actually used to access the Internet, and leave the other one empty. Use static routes if needed. And be prepared for some routing pain, anyway.
If you have a dual-homed Windows server, especially if it's a domain controller, you need to be exceptionally careful about DNS settings. Windows will by default register all of its IP addresses in the domain DNS as A records associated with its name, and a domain controller will also register lots of SRV records in order to be identified as a DC by other domain computers. If the wrong IP address ends up in the domain DNS, Pain & Suffering will ensue. Make sure to leave DNS registration enabled only on the NIC whose IP you actually want other computers to use when talking to that server (and PLEASE make this be the private NIC).
A DC which also has the DNS role installed automatically configures its NIC(s) to use 127.0.0.1 as its primary DNS server after DCPROMO. This is actually the most harmless of the configuration problems on your server, but if you want it fixed, just put your server's real IP address there. Yes, the one you want to use for domain services. Yes, the private one.
If after all of this you still want a dual-homed DC with a public IP address, at least disable file & print sharing and remote desktop services on the public NIC. Unless you want it exactly in order to RDP into your server from the Internet. If this is the case, please consider a career shift, as IT administration might really not be the right job for you.


I cant disable Proportional Editing

Question: So I was making a car, but I couldn't move a vertice. I saw that someone else had said this question and one person said to turn off proportional editing. But when I tried it wouldn't turn off. I unchecked the box that said proportional editing, but when I came back to make sure it was unchecked, it would still be checked. EDIt: It if off, but when i move any edge, vertice, or face it automatically turns on.
Comment: Have you tried hitting 'o' on the keyboard? That's the default shortcut to disable proportional editing
Comment: Yes, it but it doesnt work. Also tried Alt+O
Comment: I opened blender again, proportional editing is off, but when i   move the vertice, it turns on automatically
Comment: Interesting... I haven't had that problem, and it doesn't seem to come up a lot. There are a few similar bugs posted on developer.blender.org:

See https://developer.blender.org/T64019 and https://developer.blender.org/T64011
Comment: Same bug for me. Can't disable it
Answer: Same here in Blender 3.0, Proportional Editing comes back automatically in object mode.
My workaround:
Go in Edit Mode, toggle Proportional Editing on and off.
Back to Object Mode, select one or two bones and Proportional Editing seems to work normally after that.
Answer: I think the real culprit might be the Mirror option under the Options dropdown in each viewport.
I have no idea why it's sometimes turned on, maybe a cat walked on my keyboard. But when random vertices are moving when I don't want to, it's usually that. It needs to be turned off for every object individually.

I cant disable Proportional Editing


What word would denote a person who connects a person to another person who has the same needs, situation or struggles?

Question: What word would denote a person who connects a person to another person who has the same needs, situation or struggles? example: Cathy is a good _________. Cathy  introduced Jan and Sarah to each other because Jan and Sarah both have similar medical conditions for instance or both live in the same neighborhood for example.
Comment: Second try: Consider using *matchmaker* metaphorically.
Comment: faciitator, perhaps
Comment: In recent years, *networker*.
Comment: Possible duplication of https://english.stackexchange.com/questions/231937/synonym-for-fellow-sufferers
Comment: ***Broker*** or *intermediary*.
Answer: The general term for someone who specializes in matching supply and demand is a broker.
This is how OED puts it:

Broker
noun
II. One who acts as a middleman in bargains.
   3a. 'One employed as a middleman to transact business or negotiate bargains between different merchants or individuals' (McCulloch). Formerly used more widely, including the senses of 'jobber, agent, factor, commission-agent'.
5a. A middleman, intermediary, or agent generally; an interpreter, messenger, commissioner.

In other words, this is the famous "middleman" in "cut out the middleman".
Origins
The etymology of broker derives from Old French broceur "small trader". The earlier etymology is uncertain, but Etymonline speculates it's possibly from Old French brocheor meaning "wine retailer", which comes from the verb brochier, or "to broach (a keg)". In other words, a trader who finds people who make wine and people who drink wine and facilitates transactions between the two.
But of course, brokerage, or intermediation, is older than wine, and is a very varied field.  The general impetus behind the rise of middlemen is that suppliers specialize in creating the good or service, and consumers desire the good or service in order to meet some other end, but neither supplier nor consume specialize in searching for counterparties, and often don't have the time or will to put into the search themselves. Thus they trade capital for time and outsource the work.
Names
Given these facts, the role of broker, or middleman, has independently arisen in an enormous variety of contexts, and therefore has been given an enormous variety of names. Some of these might suit your need better than others.
Of course, there are the obvious examples of specific intermediary specialities whose name is simply "-broker" modified by the appropriate attributive noun:

stockbroker, who buys and sells financial securities to and from issuers and investors,
the real-estate broker who, employed by the buyer, understands their needs, desires, and budget at a detailed level and surveys the market for matching houses, or employed by the seller, understand the house and its attributes in detail, and seeks buyers who are willing to pay the most for that property,
the pawnbroker, who matches capital with need (i.e. makes loans), as well as makes markets in the goods forfeited as security for those loans.
the more metaphorical power broker, who influences distribution of political/economic power by exerting influence or by intrigue (i.e. he's a middle man for power)

etc, but there are also a variety of different kinds of brokers whose titles and role don't include the word "broker" at all:

the recruiter or (more pejoratively) headhunter who tries to match job openings posted by employers with candidates who have specific education and experience and vice versa
the matchmaker, who helps arrange dates or marriages, seeking to create a compatible and loving couple based on their personalities and desires. These, in turn, go by different names in different cultures, such as a shadchan¹ in Jewish culture or méirén (媒人)² in Chinese culture. Sometimes matchmakers are indeed called (as bit sarcastically, because it casts love as a business transaction) love brokers.
Continuing the financial examples from stockbroker, on certain exchanges in the US and abroad, a very specific kind of broker is literally named the specialist, who has a specific list of securities he specializes in, and is responsible for matching supply and demand to create fair and orderly markets. When not specifically designated by an exchange, the more general term for this role is market maker (of "high-frequency trading" fame).

Filling in the blank
You say:

Cathy is a good _________. Cathy introduced Jan and Sarah to each other because Jan and Sarah both have similar medical conditions or instance or both live in the same neighborhood for example.

Given the foregoing, and the amazing variety of terms for specific kinds of brokers in the world, the specific label you choose for Cathy will depend on Cathy's reasons for introducing Jan and Sarah.
If Cathy thinks they'd make a good couple, she might be a matchmaker. If Sarah runs a company and Jan would be a good fit for an open position, Cathy would be a recruiter. And so on.
But the key element is Cathy is engaging in brokerage, by whatever name, so the word you're seeking will be some specialized hyponym of broker. If you want to keep it generic and not comment on the reason Cathy is making the introduction, they you can stay with the more general broker or intermediary.

¹ Or sometimes, post the 1964 musical fiddler on the roof, a yenta.
² But this is nuanced and evolving linguistic territory, which I'm not qualified to make statements about, so I'll just quote Prof. David K. Jordan of UC San Diego on the topic:

Footnote #15: Evolving linguistic nuances are such that this may or may not exactly correspond with the generic Chinese term méirén 媒人. For the mainland it seems to correspond closely with jièshàorén 介绍人 (or in the case of the most professional individuals, with hóngniáng 红娘). For Taiwan perhaps it corresponds most colloquially with a verb: a "matchmaker" is a person who happens to zuòméi 做媒 / 做媒. There are, of course, many alternative terms and associated euphemisms. One matchmaker I interviewed consistently referred to each arranged marriage as a "happy match and harmonious union" (jiéwéi liángyuán 结为良缘). Some English writers prefer other terms: marriage broker, go-between. I have not found it useful to try to draw distinctions among such terms.
Comment: But broker wouldn't really fit in the sentence suggested by the OP, would it? I mean,  Cathy might well be a broker in her life, but that has little to do with matching people with similar personal aspects.
Comment: @user159691 It depends on the flavor of broker, which is the point of the "many names for brokers" section.  For example, *matchmaker* would definitely fit if Jan and Sarah were introduced for the sake of romance. In Jewish culture, Cathy wouldn't be called a *broker*, of course, but a *shadchan* (sometimes matchmakers are known as "[love brokers](http://www.bravotv.com/love-broker)").  And there might be a different word entirely if Cathy introduced Jan and Sarah for some other reason. But the hypernym is "broker", and that's what Cathy is doing.
Comment: Well, maybe that broker  used in the above sentence  would sound odd just to me.
Comment: @user159691 I'm not saying the word to fill in the blank is necessarily "broker", but some specific hyponym of "broker", which we'd need more information from OP on why Cathy is introducing the two people to pin down more precisely.
Answer: From Malcolm Gladwell's "The Tipping Point": connector. (The other two types are "maven" and "salesman".)


Does high PSI or low PSI affect the life of a tire?

Question: Is there a method to tell the life of a tire? How can you tell if a tire is going to wear down faster than another tire? I assume puncture resistant tires wear out slowly, but I'm really curious whether I put high PSI in my tire there will be significant difference. Will high PSI raise/lower the lifespan of my tire ceteris paribus (terrain, material being the same)?
Comment: You will get the best life from the body of tire if you run a pressure near the high end of the range listed on the side of the tire.  You get best tread life, however, if you run a pressure more mid-range.  Running a tire with too low of a pressure will quickly destroy it.
Comment: @DanielRHicks it sounds like I'll need a tire with good body life if I'm going to run my tire mid-range, and a tire with better tread life if I run the pressure high. So if I buy a "lite" tire (with less side wall protection) with a max psi of 120, I would be better off putting it at a higher pressure?
Answer: Your best bet is to operate the tire in the pressure range on the tires. Check the air pressure regularly.
Nominally if you are 180 lb or more then high number.  And 140 lb or less the low number.  In between then in between.
Higher pressure maybe a longer life but still stay in the range.  If you weigh 140 lb then not worth a higher pressure for a harsher ride to maybe get a few more miles.
Race tires naturally have the shortest life.
A soft rubber tire will wear faster but have better traction.
A hard rubber tire will last longer but also poor traction and a harsh ride.
And consider $ / mile.  You can buy a $50 tire that is probably not going to last twice as long as a $25 tire.
Answer: The PSI in a tyre definitely affects the lifetime of the tyre.
 You have to check you tyre pressure regularly and make sure that you keep it pumped at the correct level. It is recommended that you pump up your tyres every 2 weeks to keep them in tip-top condition.
You'll definitely have to look at what pressures you can use as Road tyres can withstand 125 or even 145 psi on tyres with inner tubes while tubular can go up to and over 300 psi. On the other hand mountain bikes may only withstand up to 65 psi or even lees. So make sure that you check your limits and on road bike, try not to go below 100 psi as that's the minimum pressure that the beads need to hold on to the rim of the wheel.
It's a good idea to use an online calculator to check what pressure you should use with your wheels and your weight as well as the terrain that you ride, you can also get Apps for that like the Vittoria Tyre Pressure Calculator for Android.
Hope this helps.
Comment: I tried a few calculators online which told me 80/123 psi front/rear. As for the app I don't believe it's on my phone. 120 is about as high as I'll go, max for my tire.
Comment: For a standard road tyre. 120 psi is plenty, but you might want to pump it up to 100 psi just to be on the safe side as the bead has to have a good connection with the rim of your wheel.


RootController subview won't display full screen

Question: I have a custom splash screen that is built and updated during runtime.  We have a RootController that we add a subview to.  This subview contains a UIImageView and Label.  Both the UIImageView and it's parent are set to scale and are set to 1024x768.  The issue is that the subview and image appear to be displayed as 768x1024 so the bottom of the image is cut off and the width of the subview doesn't take up the entire screen.
The gist of our code is below
window = new UIWindow (UIScreen.MainScreen.Bounds);
viewController = new RootViewController ();
window.RootViewController = viewController;
window.MakeKeyAndVisible ();

Then during the transition, we use a public property pointing to the root controller to add the subview containing the image etc...
RootViewController.View.AddSubview(controllers[view].View);

The black box just covers some info I don't want shown to the world.  The grey area is the part of the root controller view that isn't being covered by the subview.
Answer: I found the solution.  For whatever reason, the following statement was causing my problem.  controllers[view].View.Frame = new System.Drawing.RectangleF(0,0,1024,768); which is called before the AddSubview statement.  No clue why this is happening.


Why an EnumSet or an EnumMap is likely to be more performant than their hashed counterparts?

Question: The following is from the Implementation Note section of Java doc of EnumMap :

Implementation note: All basic operations execute in constant time.
  They are likely (though not guaranteed) to be faster than their
  HashMap counterparts.

I have seen a similar line in the java doc for EnumSet also . I want to know why is it more likely that EnumSets and EnumMaps will be more faster than their hashed counterparts ?
Answer: EnumSet is backed by a bit array. Since the number of different items you can put in EnumSet is known in advance, we can simply reserve one bit for each enum value. You can imagine similar optimization for Set<Byte> or Set<Short>, but it's not feasible for Set<Integer> (you'd need 0.5 GiB of memory for 2^32 bits) or in general.
Thus basic operations like exists or add ar constant time (just like HashSet) but they simply need to examine or set one bit. No hashCode() computation. This is why EnumSet is faster. Also more complex operations like union or easily implemented using bit manipulation techniques.
In OpenJDK there are two implementations of EnumSet: RegularEnumSet capable of handling enum with up to 64 values in long and JumboEnumSet for bigger enums (using long[]). But it's just an implementation detail.
EnumMap works on similar principles, but it uses Object[] to store values while key (index) is implicitly inferred from Enum.ordinal().
Comment: @Geek: say you have `enum Foo {A, B, C, D, E}`. `EnumSet` will keep a bit array of 5 bits. If this set represent `A`, `B` and `D`,the bit array will be: `11010`.
Comment: A bit can have only a 0 or 1 . So how would the EnumSet represent a set that contains four Enum values ?
Answer: EnumSet uses array[] inside and a natural order with consequent consequences:

fast: get/set is called by constant time O(1), hashCode() is not used to find a right bucket
memory efficiency: the size of array is predefined by Enum size and is not dynamic

EnumMap uses Enum as a key based on the same principals as EnumSet where hash code collision is not possible