Do objects with mass "suck in" spacetime?

Question: I don't really understand the general theory of relativity (GTR) really deeply, but according to my understanding, the GTR say that gravitation is caused by the curvature of spacetime by objects with mass.  This makes some sense when you are talking about a moving object having it's course changed by the gravitational influence of another object.  It seems that gravity is changing which direction is "forward" for the moving object and the moving object just continues to move "forward".  However, what does this mean for objects that fall toward the Earth with no horizontal component to their motion?  The object wasn't moving relative to the Earth, so how can gravity change the meaning of "forward" for the object?  If gravity doesn't change the object's location in space during the fall, do the Earth and other objects with mass "suck in" spacetime?
Answer: You can indeed think of gravity as changing which direction is "forward" for a moving object. But the key idea is that gravity acts in spacetime, not just space.
An object that is sitting still in space is still "moving" in spacetime*, it's just that all its "motion" is through time, not through space. In other words, the forward direction for this particle is time. Gravity changes the forward direction for the particle to include a little bit of space as well, so it starts moving through space. That's how gravity can accelerate a particle from rest.

*Technical note: "motion" through spacetime means the transition between different points along a worldline as the value of the variable parametrizing the worldline (proper time) changes. Not to be confused with motion through space, which is the transition between different points along a spatial path as the value of the variable parametrizing that path (coordinate time) changes.
Comment: It could be a separate question, but it's probably already on the site somewhere... basically, the answer is no. The fact that GR is correct (which has been experimentally confirmed over and over again) doesn't make the existence of gravitons unlikely. They're dual descriptions; just like you can describe light as waves or particles, you can describe gravity as "waves" (GR) or particles (gravitons). Both descriptions can be valid.
Comment: +1. That has got to be the coolest "visualization" I have ever seen.
Comment: @DavidZaslavsky, I concur: That is a nicely simple and highly visual explanation of a fundamental idea: Objects move in time, so if the direction of the time vector gets angled a bit by gravity, motion in time becomes motion in space. Very cool.
Comment: So, if the GTR is correct, would that make it seems unlikely that gravitons exist?  (Should that be a separate question?)
Comment: What does "motion through time" mean?  Isn't motion a change in position over time?
Comment: Way better intuitive explanation than the rubber-sheet-analogy +1.
Comment: @NobodyNada (sorry for late response) not in the sense I'm using it here. I'm using "motion" in the sense of a transition through a range of values of some parameter, where in this particular case, the parameter is the proper time (or some other equivalent parametrization of a object's worldline). Of course you're right about the typical meaning of "motion".
Answer: You did switch from the Newtonian law to the GTR model but didn't incorporate one of the chief differences that comes from The Equivalence Principle:

A little reflection will show that the law of the equality of the
  inertial and gravitational mass is equivalent to the assertion that
  the acceleration imparted to a body by a gravitational field is
  independent of the nature of the body. For Newton's equation of motion
  in a gravitational field, written out in full, it is:
<code>(Inertial mass)  (Acceleration)  = (Intensity of the gravitational
  field)  (Gravitational mass)</code>
It is only when there is numerical
  equality between the inertial and gravitational mass that the
  acceleration is independent of the nature of the body. — Albert
  Einstein

In other words, according to GTR, interia is the same as free fall and will be the natural state (i.e., when no other forces are acting on it) of any object with mass.
Answer: This is an extremely exaggerated representation of gravity. Because the further away you move from something with mass the faster you pass through time due to time dilation. This creates a "time gradient". If you look at the image, the squirrel's head moves through time faster than its feet, so it rotates. This rotation causes the squirrel to pass through time differently and curve toward the earth. In the 3 dimensions of space, it looks like it falls straight, but in the picture, you can clearly see that the squirrel does in fact follow a curved path. It does not rotate in the three spatial dimensions, only in the fourth dimension. According to special relativity, a rotation in the dimension of time manifests as the object getting shorter the closer to light speed it gets. Technically in the last two time frames, the squirrel is moving faster than light, which breaks special relativity, but as I said, this is exaggerated. In real life, things accelerate much more slowly. It's just exaggerated for emphasis.
Answer: First, I'm not an expert on physics, but I've logged thought and research into this. Einstein said that accelerating in a spaceship at 32.17 ft/s^2 would be the same as standing on Earth and that the ground is actually pushing us upward.
I believe you are right. Gravity sucks space-time; it does not bend it.
Therefore, a falling object does not move until it hits the ground. Think of the ground, in this case, as the spaceship. Here is the scary implication, every object of mass is "sucking" space-time faster and faster and we are by consequence accelerating, otherwise we would not have gravity.
The moon is said to be moving in a straight line in space, if it cannot have a negative y-component, then neither can a falling object with no x-component.
The moon itself, traveling in a straight line, appears to move close to Earth because the space it enters at point B was actually much higher when the moon was at point A. I wouldn't doubt if you studied Kepler's Laws you could mathematically prove this, and I'm sure somebody already has.
I have been told by an astronomer at Cornell that this is not the case, that falling objects go in a straight line down as the moon goes in a straight line sideways, but this is too contradictory for me. I think some people have trouble fully comprehending Einstein's ideas, but now that I do, it's way too simple.


Number of GWT RemoteServiceServlets

Question: When designing an application with a large number of remote services, is it better to have one RemoteServiceServlet end point with many methods or a large number of RemoteServiceServlet endpoints with fewer methods?
Answer: I would go with lots of RemoteServiceServlets, one per area of functionality or module in your application. Otherwise you end up with a "kitchen sink" of unrelated functionality all in one class.
Answer: I am afraid that the question doesn't list the correct answer.
The command pattern offers you single end-point / single method solution for GWT-PRC.
Please see this presentation and you might find this out of the box implementation helpful.
Answer: I would suggest  that you integrate your server side with some sort of dispatcher servlet like Spring, so you can ease the development, and then go with David Tinker's suggestion. You should design your app according to your functionalities.

Number of GWT RemoteServiceServlets


Android Application kill event capture

Question: I want to perform some operation when my application gets killed.
Which method can be used for this? I am working on Android 5.0.
Answer: The key of this question is that:

you must understand your application whether can receive any
  additional callbacks when your application being killed in any kinds of situation.

The following answer is answered by Devunwired in this question:
Android app doens't call "onDestroy()" when killed (ICS)
This will help you more to understand this.

Your application will not receive any additional callbacks if the process it terminated by external means (i.e. killed for memory reasons or the user Force Stops the application).  You will have to make do with the callbacks you received when you app went into the background for your application cleanup.
finish() is only called by the system when the user presses the BACK button from your Activity, although it is often called directly by applications to leave an Activity and return to the previous one.  This is not technically a lifecycle callback.
onDestroy() only gets called on an Activity as a result of a call to finish(), so mainly only when the user hits the BACK button.  When the user hits the HOME button, the foreground Activity only goes through onPause() and onStop().
This means that Android doesn't provide much feedback to an Activity to differentiate a user going Home versus moving to another Activity (from your app or any other); the Activity itself simply knows it's no longer in the foreground.  An Android application is more a loose collection of Activities than it is a tightly integrated singular concept (like you may be used to on other platforms) so there are no real system callbacks to know when your application as a whole has been brought forward or moved backward.
Ultimately, I would urge you to reconsider your application architecture if it relies on the knowledge of whether ANY Activity in your application is in the foreground, but depending on your needs, there may be other ways more friendly to the framework to accomplish this.  One option is to implement a bound Service inside of your application that every Activity binds to while active (i.e. between onStart() and onStop()).  What this provides you is the ability to leverage the fact that a bound Service only lives as long as clients are bound to it, so you can monitor the onCreate() and onDestroy() methods of the Service to know when the current foreground task is not part of your application.
You might also find this article written by Dianne Hackborn to be interesting covering in more detail the Android architecture and how Google thinks it ought to be used.
Answer: You can use your activity's onDestroy() method.
Comment: Tried using onDestroy() activity but it doesn't works , I have to capture application getting kill event ...
Comment: Then you should try making the separate Service application, which would capture this event.
Comment: Thanks !                                                                                This issue got resolved by creating a shell script which will run in background and will monitor the application process status,Once it find process is missing it will invoke the task which need to be completed.
Answer: You have to use Service Class for it like -
public class Myservice extends Service { @Nullable @Override public IBinder onBind(Intent intent) { return null; }

@Override public int onStartCommand(Intent intent, int flags, int startId) { Log.d(Constants.TAG, "Service Started"); return START_NOT_STICKY; }

@Override public void onDestroy() { super.onDestroy(); Log.d(Constants.TAG, "Service Destroyed"); }

@Override public void onTaskRemoved(Intent rootIntent) { Log.e(Constants.TAG, "END"); //Perfome here want you want to do when app gets kill stopSelf(); } }

In Manifest -
<service android:name="Myservice"
            android:stopWithTask="false" />

In Oncreate of your launcher activity or Application Class to start service -
startService(new Intent(getBaseContext(), OnClearFromRecentService.class));

Comment:   add this line to the manifest in application tag
Comment: Not working in android version>=26.

Android Application kill event capture


Putting data in different columns in database table

Question: Is it possible to put data in different columns in the database table but using the same variable used? For example, for column1 is # of hours worked for day1, while column2 is # of hours worked for day2, etc.
Comment: Don't do this. Instead, add a column for DateTime which stores the dates, then a single column for # of hours worked on that day. Or, a start and end date. This is going against normalization and would grow beyond a table's maximum number of columns (eventually). I didn't DV you BTW.
Answer: Try to normalize the database instead of having all the columns in one table.
You can have one table for all the user information (idnum, first_name,last_name,address) and another table for storing the working hours (idnum, date, timein, timeout).
Use time columns as DateTime.
Answer: Normalize your tables by separating concerns. In your case create three tables namely; users, address, and hours. Specify Primary Keys (PK) in each tables. Use a Foreign Key in your users table to relate to two child tables; address and time_card. Primary keys are idnum, addr_id, and time_id. The last two ids are also foreign keys in the users table. Example table schema and data shown below. Hope this helps.
users
idnum | first_name | last_name | age  | addr_id | time_id
123   | james      | cord      | 32   | 22      |  856
address
addr_id |  street1        | street2 | city     | state | zip
856     | 6830 Woodley Av | Apt 26  | Van Nuys | CA    | 91405
time_card
time_id | time_in | time_out | date       | day_of_week
22      | 8:00 AM | 5:00 PM  | 08/16/2017 | 3


Is it permitted to have an American Flag on a flagpole with an Eagle on top in a Synagogue?

Question: American Flag on pole, topped with an Eagle.
Is this permitted in the Synagogue?
Comment: https://shulchanarukh.alhatorah.org/Full/Yoreh_Deah/141/6#e0n6
Comment: @wfb is quoting a source that isn't immediately clear, so I'll explain: According to טורי זהב (a highly valued halachic commentary), one should not have symbols of animals or the like in a synagogue (because it may give off the impression that one is bowing to them).
Comment: @EthanLeonard that meant not to decorate your synagogue with them, agreed. I think it's a very plausible argument that an American flag with a finial is ... seen as just a flag. Half the crowd probably doesn't even notice the eagle unless they are paying very close attention. But hey, Chumra of the month club ... if you have the choice of finials, yeah get a simple knob shape instead.
Comment: @Shalom you could be right. I was just translating the source, which doesn't explicitly differentiate between finials and any other type of symbol (unless I missed something).
Comment: @EthanLeonard not per se, though it sounds like he's discussing symbols to decorate the synagogue; this is more like a decorator for the political statement.
Answer: Rabbi Moshe Feinstein wrote that US and Israeli flags inside the synagogue (i.e. the worship room itself) were permitted; there was nothing idolatrous about them. He felt they were less-than-ideal, simply as the prayer room should be dedicated only to prayer. He stressed it was far better to pray in a dedicated synagogue, even if it had flags, than in someone's basement.
He did not address the finial per se, but I'm going to make a reasonable guess here -- most of the synagogues I've seen that have flags (whether in the sanctuary or the lobby) have had eagle finials. I'm pretty sure that was the standard practice at the time Rabbi Feinstein wrote his responsum. So when he said "it's not idolatrous to have a US flag in the sanctuary", I think that means "even if it has the little eagle thingy on top." Provided no one is actually worshiping the thing... otherwise we have bigger issues...


Is it "what movie did you watch?" Or " which movie did you watch?"

Question: I'm confused about the right way of saying it. Please tell me the correct answer and why it is correct.
Answer: What movie is for when you dont know the selection of movies.
Which movie implies there was some sort of list, and they chose that one from there.
In most cases "What" would suffice, unless for example, you watched a movie at the same time too and you just saw your friend coming out of the cinema

Is it “what movie did you watch?” Or “ which movie did you watch?”


Reason for thread pooling

Question: Can someone explain what is the reason for thread-pooling in Linux, even if the threads are light to create and destroy??
Answer: Not as light as you think.
Thread pooling is orders of magnitudes lighter, so you can use pooled threads for gazillions of tiny tasks and still be efficient, while the same with freshly created threads would be inefficient.
In my environment, I can use five different threads in ten lines of code (without you even seeing that I'm using threads), which is possible because of highly efficient thread pooling).

Reason for thread pooling


What can be some strong reasons not doing a masters?

Question: I am writing a motivation letter where I have to write why I am directly applying for a Ph.D. position without masters. What can I write so that it seems valid and convincing to the professor?
(The Ph.D. will take 4 years anyway for people who will apply from bachelor, the 1-year preliminary course then 3 years Ph.D.)
Comment: What about the actual reasons you are applying for phd and not masters?
Comment: You should probably add some information about the program you are applying to and the location (and how common it is to do what your are doing).  In some regions and fields, going straight to a PhD is the norm and requires no explanation.  In others it is extremely unusual and will need significant justification for skipping what is viewed as a critical step.
Comment: I was thinking to apply to the USA to be very honest. But this position is from Germany, so I thought to give it a try. And they said they accept the student from bachelor (fast track Ph.D.). This position is for 3 years. If you don't have masters, then you will need additional one year for some preliminary courses.
Answer: For any application, for school or a job, the key thing is to make sure that everything in your application indicates a successful future. In Germany, where a masters is mostly "expected" it might be hard to convince an advisor that you are ready unless you have done some exceptional things otherwise. Having the master's gives the PI a better chance to evaluate your future, based on your past. So, there, and in some similar places, the hurdle is pretty high.
In the US, by contrast, less is expected since the program is longer and involves coursework that can be used to help make predictions. Also, in the US, you choose the advisor later, giving everyone a better chance to evaluate.
But, what you can write to convince people must involve listing your past successes and other suitability for the proposed position. Just being a good student in a classroom situation probably isn't enough. A different situation if you have some research behind you and some publications.
Convince with deeds, not words, but get letters of recommendation that back you up.
Comment: In Germany, the masters degree is not only "expected". It is (generally) required. Being allowed to do a PhD without it is a (rare) exception.
Comment: @Roland, while I agree, the OP is in Germany and seems to be referring to an exception.
Answer: You can simply write that you want to pursue your career in research. PhD are made mainly for research. Keep in mind that in Europe it is not possible at all to be enrolled in PhD if you didn't finish your master's degree before (3years bachelor + 2years master + 3/4years PhD in Europe).


Why can't we see the far rims of our galaxy by ordinary light?

Question: I mean what is the relationship between the empty space between stars
such that it contains sparse distribution of gas and our our inability to see
the  rims of our galaxy.
I searched too long time to  get an answer but I did not get any thing.
Comment: Not sure I understand your question, what edge you are referring to. Maybe you can give us slightly more background on what you mean in an edit to this question. Do you assume that our Galaxy has some kind of sharp edge where in the inside there is some gas, and outside in the intergalactic space there is not?
Comment: @planetmaker that is exact what I mean . From our position inside the Milky Way Galaxy, we cannot see through to its far rim (at least not with ordinary light) because the space between the stars is not completely empty. It contains a sparse distribution of gas (mostly the simplest element, hydroge
Comment: Oh we DO see to its rim (not every direction, of course) - but that's similar to how here on Earth and the atmosphere: we see the atmosphere, but not the rim - there simply is none, it gets thinner and thinner the further we go. And we don't see it at all where Earth is itself (thus where most stars especially in the Galactic center direction are and thus somewhat hide the far edge of the milkyway)
Answer: Mixed in with the interstellar gas (which has almost no effect on visible-wavelength light by itself) are dust grains, which scatter and absorb light. Because the density of gas and dust increases as you get closer to the center of the galaxy, looking in the direction of the center of the galaxy (or nearby directions) means trying to look through a lot of dust -- more and more if you consider trying to see things farther and farther away from us -- and this ends up blocking most of the light. In visible-wavelength light, we can't even see the central regions of the galaxy, let alone the far side of the disk beyond the center.
But if you look in the opposite direction, you're looking in a direction where the density of (gas and) dust gets lower the further out you go and where the "rim" of the galaxy is closer to us. So it's generally possible to see the near "rim" of the galaxy.
(With the caveat that galactic disks -- including our own -- do not have "rims" in the sense of sharp edges.)


How can SpaceX's Mars spacecraft be protected against solar flares?

Question: When a solar flare hits the earth it can damage certain electrical equipment. If one manages to strike the SpaceX Mars rocket it could possibly damage some significant equipment on board (like navigation and life support). So what can these rockets do to protect themselves from these harmful solar flares and other radiation.
Comment: Protection of the electronics would be easier than of the astronauts. But a radiation shelter for astronauts might be necessary.
Comment: Many spacecraft have landed on Mars already. A manned mission will be larger, which will by it's nature offer more protection. Why do you think this particular application would be more difficult then any other mission that has gone to Mars?
Comment: Sometimes bigger mass doesn't mean more protection. Think about secondary radiation, that will be produced when the flare particles will be scattered by the shielding materials.
Comment: For NASA's planned Orion mission there's a procedure where the astronauts relocate all the storage containers and boxes to form a sheild at the center of the spacecraft and then hide there for the duration of the solar flare
Answer: There are three ways we can do with existing tech.
The first is to shield the ship with water.  Build the ship like a double-hulled oil-tanker and fill that void between the hulls with water.  Water is an excellent absorber of radiation.  That water would still be drinkable because gamma-radiation (the type you get from the sun) doesn't contaminate what it hits.  The worst a particle would do is cause some hydrogen and oxygen bubbles to form in the water as it smashed the water apart.
The second is to equip the ship with a big magnetic field that would deflect the particles as they approach the ship.  All of those particles are ionized so most of them will be deflected by a magnetic field enough to avoid the ship.
Lastly, you want a "storm-cellar"- a big old lead container.  For those really bad days where the other two systems aren't enough.
The downside to all of this is weight. Water is heavy and lead is worse; the magnetic option would require something that generates a LOT of power, so that would be heavy too.
Answer: Protecting electronics is not a big problem. The feared major impacts on electrical systems on Earth involve interactions between a flare (or coronal mass ejection) and Earth's magnetic field.  Once you are away from Earth you get the direct particle impacts, but not the electromagnetic effects. These can cause transient local failures, but spacecraft systems are routinely designed to recover from there.
Protecting humans is a different problem. Most designs feature a protected "storm cellar" within the ship (for instance a space surrounded by relatively absorbent water tanks and food supply lockers, into which the astronauts can retreat for a few hours or days when necessary.


Should I use "had had", "did have", or "had"?

Question: When using "double words" such as "had had", is this grammatically correct, and is there a better way to say the sentence?
Which of these is better?

He had had a drink
He did have a drink
He had a drink
Comment: The second _had_ is the main verb, the first is an auxiliary verb making the past perfect tense. There is nothing at all incorrect about repeating the word if this is called for by the required tense. None of your examples is 'better' than the others, they just have different meanings.
Comment: You need to look up and study tenses of verbs, and use of the emphatic did. Here the verb **have**.
Answer: None of these are "better" or "worse", they just mean different things.  Let's examine them in reverse order.
3. He had a drink.
This is the simple past tense.  It means that at some point in the past, he drank something.
2.  He did have a drink.
This looks like the emphatic do, in the past tense.  It means the same thing as #3 (at some point in the past, he drank something) but the addition of do adds emphasis.  You might use it in an exchange like

"I know he didn't drink anything."
"You're wrong, he did have a drink."

1.  He had had a drink.
This is the past perfect tense.  It means that he drank something before another time in the past.  You might use it like "He thought about driving home (so the thinking was in the past) but he had had a drink (having a drink was in the past, before the thinking)."
It looks confusing, because of the "had had", but the first had is just the auxiliary verb of the past perfect (as in had eaten, had slept, had thought) and the second had is the past participle of to have (just like eaten, slept, and thought are the past participles of eat, sleep, and think).
Answer: This happens because of a coincidence in English.
Many English verb phrases are formed by an auxiliary and a main verb. The auxiliary gives the tense and and aspect, and the main verb gives the meaning.

He is [auxiliary] eating [main verb]

He has [auxiliary] written [main verb] a book.

Now it is possible to form a sentence in which both the main verb and the auxiliary are forms of the verb "have".

He has had a biscuit.

This is a perfect tense, and it uses the past participle "had".
Now it is a coincidence that the past tense form of "have" is also "had"!  (In most languages with participles, the participles are different from the past tense - English is a bit weird)
If you for the past perfect you get:

He had had a biscuit.

It looks odd but the two words are the same, but functioning differently. The first is a past tense auxiliary and the second is a past participle main verb.
You can get the same thing with "do"

"I do up my shoelaces" (normal)

You never do up your shoelaces.
You're wrong! I do do up my shoelaces, every day!

And with other words that happen to have the same form.  For example the verb "bat"=hit and the noun bat=flying mammal.

He bats bats with a cricket bat.

We would often try to avoid these double words, but sometimes they are essential to the meaning that we want to give.


Use of aliases in contracts between parties

Question: Aliases were used in the infamous hush agreement involving Donald Trump and Stephanie Clifford. The alias for Donald Trump was David Denison and the alias for Stephanie Clifford was Peggy Peterson. Did the document state who the aliases stood for? How could the agreement be enforced as an agreement between Trump and Clifford if it seems the agreement involved neither of them?
Answer: A contract is an agreement between 2 or more people - who cares what they call themselves?
If someone asserts that the person named in the contract is you and you assert that it isn't then they would need to provide sufficient evidence to prove it was you on the balance of probabilities. It the contract has your name on it rather than an alias this is obviously easier.


Tap event and tapped item

Question: I have a multiselect ListBox from the Toolkit and I want to show the tapped item in a new page.
How can I extract every item from the tapped item? Every item has 4 fields.
This is the code that fills the ListBox:
<code>void client_DownloadStringCompleted(object sender,
                                    DownloadStringCompletedEventArgs e)
{
    if (e.Error == null)
    {
        string xml = e.Result;
        XDocument data = XDocument.Parse(xml);
        var persons = from query in data.Descendants("Table")
        select new MailList
        {
            Sender = (string)query.Element("FromUser"),
            Body = (string)query.Element("Message"),
            Date = ((DateTime)query.Element("mDate")).ToString("MM/yy"),
            Time = (string)query.Element("mTime"),
        };
         EmailList.ItemsSource = persons;
    }
}
</code>
I want to send to the other page the Sender and the Body field.
Thanks.
Answer: its very simple...
On the other page, create a public static variable called SelectedMailingList of type MailingList.
On tap, set the other page's SelectedMailingList property and then Navigate to the page.
have a look at this sample.. I use the same mechanism..
http://wp7pivottest.codeplex.com/
Comment: can you write me an example? Thanks
Comment: I didn;t find any relation for what i'm looking for in your example.
I want to take the sender and the body of the tapped item in the listbox.
Thank s again
Comment: the selected item on listbox will be an instance of the class. all you need to do is set the static property of the page you want to send it to
Answer: I would recommend passing Navigation Query Strings Parameters described in below links
http://forums.silverlight.net/t/223044.aspx
http://msdn.microsoft.com/en-us/library/system.windows.navigation.navigationcontext.querystring(v=vs.95).aspx
Its easy to implement, I hope it helps

Tap event and tapped item


procedure of statistical modeling of sample

Question: I never did the statistical modeling of sample. Usually i was engaged in common  statistical procedures(descriptive statistic, correlation, regression, factor analysis and so on). Now i decided find out how simulate any sample? for example,
i need simulate sample of 200 people. Suppose, it's psychological research, i have any methodics and each of them has  certain parameters(scales).
imagine that each methodics has 5-10 scales and we have 5 methodics. Finally, we have to work with 25-50 parameters.
What i must know and must do to simulate my sample?
and how modeling procedure can be done using SPSS or statistical software?
For a start, suppose that 100 people of sample are men, and 100 people of sample are women,
and my hypothisis that mean values of each parameter are different between men and women (using Anova)
and correlation between parameters are different in men and women
Answer: I found answer. there is menu in statistica 10. it's called Distribution fitting. So it menu has many methods for simulations any sample.


Why is the Giant Hothead/Flashwing not working?

Question: The Giant Hothead seems to not be working - do you have any ideas on whas is causing the failure, and what we can do to fix it? We also have a Flashwing that wont work - again, do you happen to know how to fix it?
Comment: What do you mean by not working? Do they fail to connect? Do you get any sort of error message? What system are you playing on? Give us as much information as you can, and it will be easier for us to help you.
Answer: Occasionally, the physical figures have problems.  There's not really anything to be done except return/exchange them, or buy new ones if they're outside of the return window.  My brother had one that didn't work right out of the package, and he had to return it for a refund.  It's not specific to certain figures; any of them can fail without warning as far as I know, although it's not common at all.


Blender file size is getting high

Question: I have imported assets in blender and saved it. After I have added some assets and deleted the old ones. But the file size keeps on increasing.
Comment: I downvoted your question because it is vague and devoid of any information that would allow us to diagnose your problem. Please edit it and provide more details so we can help you.
Answer: You are very low on detail about your problem so it's difficult to help. We don't even know the assets type you are talking about nor your Blender version.   Plus there are some topics about such problems you could have found by yourself by google-ing it. But here are some tips :
First, check out that topic.
Then, if you have a bunch of images, like said in the upper topic you have to go on the Outliner's Blenderfile mode, navigate to your unwanted images and Right-Click → Delete everything you want to delete. You can also use the UV/Image editor, open your unwanted images and Shift-Click the X icon in order to force deletion.
In order to apply all these actions, you have to save your blend file then re-open it.
If you need more, I think you can find a lot everywhere too.

Blender file size is getting high


A word that describes non physical "activity"

Question: With online communication being predominant today what is the collective word that describes accusations, generalizations, insults in people's comments?  It is not a behavior or conduct since no actual physical activity take place. I want to say for example, "people who engage in such ?????...are..."  "Mental activity" is the only thing that I came up with.
Comment: You're overlooking the fact that insults etc. need to be communicated through physical activity - spoken, typed, whatever. And the general word for what you're describing could be *slander*.
Comment: Why does you  definition of behaviour not include online activity? After all "online behaviour" is a common enough ideom?
Comment: Look in a thesaurus for behavior or conduct.
Comment: The way I understand behavior, one has to physically do something, yell, break, jump etc.  Accusations, generalizations and insults are abstract concepts.
Comment: People who engage in  " insulting, accusing, generalizing" are ...whatever.  I want to replace "insulting, accusing, generalizing" with a collective word(s)
Comment: *Behaviour* and *conduct* are both applicable to online activities.
Answer: I want to say for example, "people who engage in such trolling...are..."
OED:

Draft additions March 2006
Troll (v.)  intransitive. Computing slang. To post a deliberately erroneous or antagonistic message on a newsgroup or similar forum with the intention of eliciting a hostile or corrective response. Also transitive: to elicit such a response from (a person); to post messages of this type to (a newsgroup, etc.).
1992   Re: Post the FAQ in alt.folklore.urban (Usenet newsgroup) 8 Oct.   Maybe after I post it, we could go trolling some more and see what happens.
2005   B. McWilliams Spam Kings iii. 69   Once, after a spammer trolled Nanae, accusing antis of having no life, Mad Pierre sarcastically responded that the spammer was correct.

Probably from the angling/fishing term "to troll"

V. Senses relating to angling.

Angling. intransitive. To angle with a running line (? originally with the line running on a 'troll' or winch); (also transitive) to fish (water) in this way;

[See also] v. 10a, 10b;  (c) (in U.S. and Scottish use, perhaps through association with trail or trawl) to trail a baited line behind a boat; also figurative.In quot. 1606   perhaps confused with trawl n and v.
1606   S. Gardiner Bk. Angling 28   Consider how God by his Preachers trowleth for thee.
1891   A. Lang Angling Sketches 5   Trolling a minnow from a boat in Loch Leven—probably the lowest possible form of angling.
1966   'E. Lindall' Time too Soon iv. 51   Kamindo had rebuffed him when he had trolled for information.

A word that describes non physical “activity”


If electrons are waves, how do they repel each other?

Question: Louis de Broglie said that electrons are waves. But how they repel each other?
Answer: Electrons aren't waves or particles. Instead they are excitations in a quantum field called the electron field. The interactions between electrons are described by the equations of motion of the electron field.
However de Broglie was correct in the sense that if we consider an isolated electron this can be approximately described as a state of the electron field called a Fock state, and this is basically a plane wave. So for an isolated free electron it is a very good description to consider it as a wave. There is more on this in my answer to What is a subatomic particle? if you're interested in pursuing it.
However if we have two electrons then the state of the field is not just two Fock states superimposed. If it were then the electrons wouldn't interact so there would be no repulsion between them. In fact we can't solve the equations for the field state directly so we use a technique called perturbation theory to approximate what happens. If we consider two electrons heading towards each other, interacting and then heading away from each other. The calculation is done by summing up a series of calculations represented by Feynmann diagrams. You've probably seen Feynman diagrams like this:

This shows the two electrons interacting by exchanging a virtual photon, but be careful about interpreting this literally as it's just a representation of an integral called a propagator. No virtual photon actually exists. What we are doing with these diagrams is calculating how the two Fock states interact and in the classical limit this gives us the force between the two electrons.
Answer: Electrons are point particles in the standard model of particle physics, as seen in the table. They are quantum mechanical entities: when detected they leave  a particle footprint within the Heisenberg uncertainty principle.
Here is an electron in the hydrogen bubble chamber, it leaves a consecutive macroscopic footprint of a charged particle moving in a magnetic field. The dots are small scatters off the hydrogen atoms which compose the bubble chamber.

Where is the wave nature? At the original interaction vertex when the K- hit the hydrogen atom and transfered enough energy to give kev energy to the electron. The probability of this happening is the square of the quantum mechanical wavefunction for the interaction: K-  + hydrogen atom ----> e- K- H+ .
The single electron double slit experiment shows both the individual footprint, and the wave nature of the interaction : "electron scattering of double slits" . The single electrons look random on the screen. The accumulation which is a probability distribution,  gives the  interference pattern of a wave nature.


Nodejs detect browser pushState

Question: I currently have res.redirect('/login') but this will not work for browsers not supporting pushState. So I need a way to detect the user browser so that I can redirect with res.redirect('/#login') for browsers not supporting pushState.
How can I detect if the user browser supports pushState or not in Nodejs?
Answer: You could implement ua-parser and then use the, Can I use... matrix to build which browser versions support it. It's not very ideal but I can't think of another way to feature detect from node.
Answer: You can use a cookie to transport that value to the server. Otherwise, it will be pretty hard to distinguish between clients (eg. in case you want to send an HTTP request containing the relevant data). To receive the cookie, you would need to send an HTTP request after setting it.
Using user agents to detect features is not future-proof, don't do that.
As a side-note: After Twitter removed support for hash-bangs recently, you could continue to support this great way of showing an users position on a webpage. (Seriously, don't do that.)

Nodejs detect browser pushState


Arduino compiled sketch on sd card

Question: Hello I have just got my Arduino to read text from a text file and it is running perfectly. I was interested in being able to load a sketch into the Arduino and having it execute it, from and SD card. The Arduino wouldn't be connected to my laptop at all. I researched it and it is possible, with a different boot loader. Which is a bit annoying because I don't want to change the boot loader on my Arduino. I could put it on a standalone atmega chip but lets pretend I don't have those. So I was thinking if you had pre-compiled Arduino code. Which is in hex format and ready to be put on the board, would it be able to be loaded from the SD card? If so how would I go about doing this?
Answer: Yes it is possible:
With a different bootloader.
You need something which will erase the old sketch from the chip, read the data from the SD card, and write that into the flash of the chip. The only thing that can do that is the bootloader or some external device (another ATMega328p chip which we have to pretend you don't have).
Due to the way the architecture works you can only execute code out of the flash, so you need to program your sketch into the flash somehow. And that is the role of the bootloader.
Comment: what if I had a sketch uploaded to the Arduino that uses about 50% of the flash space or more/less. If I had my really basic kind of language that I can load as a text file into a set of strings in the sketch's progmen. That part is possible. The sketch I write would be able to understand what the text file means.It might be just something like: print "hello world". That part is possible. Now the part I don't know about. When the sketch is finished with that "homemade language programme" it would have to clear it from its progmem and use those strings to load an new homemade language programme
Comment: If you were going to do that you could just read the text line by line from the SD card and act on it - no need to program anything into the flash.

Arduino compiled sketch on sd card


Unable to link CSS to the template url react content query web part

Question: I have just installed the react Content query web part and I am linking the template url to html files in my site assets, I have a common css which has some elements common across different templates but though there is proper reference it is unable to render the stylesheet has anyone come across this issue
Answer: Per my test it works well, I copy the existing tempalte then create a new html file which change the font to 100, upload it to site assests library, fill in the template URL, it will show the changed font.

Please make sure the template is correct, also try to edit the template content directly to compare the result.
Comment: Thanks for responding to the query Julie , the only issue is that is that it doesn't take the color property in the external stylesheet, but if I put the color property to pick up site theme color in the internal stylesheet it works
Comment: what did you mean external and internal stylesheet?


Countability of Church-Kleene ordinal in ZF

Question: In the set theory ZFC if we define the Church-Kleene ordinal as usual, it is the least upper bound of a countable set of countable ordinals, then is countable itself because $\aleph_1$ is regular, but if we don't consider the axiom of choiche what happen (i know that $\aleph_1$ is not more necessarily regular)?
It is always true that the Church-Kleene ordinal is countable?
Comment: You can give a surjection from the (countable) set of Turing machines to the Church-Kleene ordinal, hence it's countable.
Comment: It seems to me that the conclusion doesn't follows directly by the premises, in fact in ZF, in general it isn't true that if $f:A\to B$ is a surjection then there exist a $g:B\to A$ injective.
Comment: @G.Ottaviano A surjection from a *well-orderable* set always splits, though: if $A$ is well-ordered by $\trianglelefteq$ and $f: A\rightarrow B$ is a surjection, then define $g:B\rightarrow A$ by sending $b\in B$ to the $\trianglelefteq$-least element of $A$ which $f$ sends to $b$. And countable sets are well-orderable, of course. (Note that this is basically what the first paragraph of my answer does.)
Comment: Than you Noah for the explanation, now i understood.
Answer: The countability of $\omega_1^{CK}$ has nothing to do with the axiom of choice: consider the map $\omega_1^{CK}\rightarrow\omega$ sending $\alpha$ to the least index of a Turing machine which computes a copy of $\alpha$. This is clearly an injection, hence $\omega_1^{CK}$ is countable.
In general, for any "simple" notion of definability, the least ordinal not definable in that sense is countable, and this is witnessed by the map sending a definable ordinal to the least number representing a definition for that ordinal. If you're interested in such "first undefinable ordinals," you may find this summary of Madore worthwhile.
(Why did I say "simple" in the above? Well, it turns out that we can run into some odd phenomena in general - see for example this article of Hamkins, Linetsky, and Reitz. But this isn't an issue here.)
Answer: Let me give you a different—and slightly more convoluted—argument than the direct one given by Noah, in hope to present a different way of seeing these type of problems.

Turing machines are absolute between $V$ and $L$. This means that every computable $\alpha$ is also computable in $L$. In particular, every $\alpha<\omega_1^{CK}$ is countable in $L$.
Every computable $\alpha$ in $L$ is also computable in $V$. Therefore the definition of $\omega_1^{CK}$ in $L$ must be the same as in $V$. Since $L$ satisfies choice, this is a countable ordinal in $L$, so it must be countable in $V$.

The key point here is the combination of these two parts:

We have an inner model satisfying choice, which agrees with $V$ on what it means to be computable,
and being countable is a $\Sigma_1$ property, so it is upwards absolute.

This can be used in a myriad of situations. For example when we want to argue that the diagonal intersection of $\kappa$ closed and unbounded subsets of a regular $\kappa$ form a closed and unbounded subset of $\kappa$, we can do this by checking manually the usual proof works, or we can argue in some inner model of choice that captures our sequence of clubs, and use the fact that you cannot destroy a club subset of a regular cardinal to argue the diagonal intersection in the inner model is still a club in $V$.
Comment: +1. Note to the OP: these answers are related, in that absoluteness between $V$ and [Godel's $L$](https://en.wikipedia.org/wiki/Constructible_universe) is a consequence of [Turing machines being nicely definable](https://en.wikipedia.org/wiki/Absoluteness#Shoenfield's_absoluteness_theorem).


Does an electric grill make it faster than a pan?

Question: My teflon pan heats up for several seconds (to roasting temperature). When I tried 1500W teflon electric grill (in a shop) it took much longer. But electric grill is two sided, so parallel roasting of two sides. So what is quicker and how much?
Answer: They are different tools.
The main problem with an electric grill (two sided) is that is has a lot more parts and pieces that can break and is harder to clean.
The other big problem of an electric grill, is that it is mostly a single use tool compared to a frying pan that you can use for a ton of different applications.
For example, you want to grill some chicken breasts, you can do it in a pan and in a two sided electric grill; but lets say you want to make a sauce/gravy, in the case of the frying pan, you already have the tool to do it, in the case of the grill, you will have to use another tool  (pot or pan) to do it.
As for the cost, here, in Canada, you can find cheap ones (foreman grill) at around 30$.
Comment: Yup - my 'George' does sausages & cheese toasties [think Breville if you remember those, but bigger] - for everything else I've got frying pans.
Comment: @RS - 15 years or so. It's gone the way of most half-decent teflon coatings; it's not that it comes off, but over time it gets coated with 'burn-on' that you can never satisfactorily get rid of. So it's not as non-stick as it was when new, but it's still fine.
Comment: @RS - I've got the one he used to advertise on the TV in the UK, waaaayyy back -  the "Lean Mean Fat Reducing Grilling Machine", model 10032. I bought it for a tenner on eBay & it's still going strong. https://i.stack.imgur.com/18ZgT.jpg
Comment: @Tetsujin how old is your grill, I've seen pretty bad reviews when people told that non-stick coating falling off quickly.
Comment: @Tetsujin great, what model?


Were Abiram and Segub the sons of Ahab or Hiel? Are their deaths accidental or intentional?

Question: "And Ahab made an Asherah. Ahab did more to provoke the Lord, the God of Israel, to anger than all the kings of Israel who were before him. In his days Hiel of Bethel built Jericho. He laid its foundation at the cost of Abiram his firstborn, and set up its gates at the cost of his youngest son Segub, according to the word of the Lord, which he spoke by Joshua the son of Nun."
1 Kings 16:33-34 ESV
Comment: Welcome to the site Rialynn. Be aware that questions that are "opinion-based" are often ruled off topic here. However, I think it's an important question and have therefore given a pro-and-con answer instead of expressing my personal opinion.
Comment: By the way, the question is quite thought provoking. For future reference it might have been better to explain why you think that their being Ahab's sons was a real possibility.
Answer: This verse is reporting the literal fulfilment of the curse announced by Joshua in Joshua ch6 v26, on anyone who dared to rebuild Jericho after his own destruction of the town.
I suggest that a curse is threatening an event which will be against the will of the person being cursed. So their deaths would not have been by Hiel's intention, anyway. But a deliberate murder by somebody else, for whatever reason, would fulfil the curse as effectively as an accidental death, if it occurred at the right time. We don't have enough information for a definite answer.
Answer: Whose Children?
Grammatically, the text suggests that the two sons where the children of Hiel of Bethel, not of Ahab. It was during Ahab's reign that the event occurred:
1 Kings 16:34

During his (Ahab's) reign, Hiel from Bethel rebuilt Jericho. At the
cost of Abiram, his firstborn son, he laid the foundation, and at the
cost of Segub, his youngest son, he set up the gates

On the other hand, the OP's question about this is not as farfetched as it might seem at first glance. Were these actually Ahab's sons? This could indeed be the case if Hiel - knowing of Joshua's curse - demanded that Ahab provide two sons as a sacrifice in order to protect himself (Hiel) from the curse. In this scenario Hiel would be Ahab's agent who required a kind of "insurance policy" in carrying out Ahab's instruction to fortify Jericho.
Accidental or Intentional?
Since the grammar of the text suggests they were not Ahab's sons I will proceed on that basis. Commentaries vary widely as to whether the deaths of Hiel's two sons in the rebuilding of Jericho were accidental or intentional. If they were put to death intentionally the question arises as to whether Hiel offered them to God of Israel or to a pagan deity.
One argument in favor of this being a case of human sacrifice is the fact that the previous verses provide a catalog of the evil religious traditions practiced under Ahab's reign. There is also one piece of historical evidence that supports the idea of an intentional sacrifice. The Interpreter's Bible reports that archaeological digs at Jericho have unearthed evidence of child-sacrifice at the site consistent with the time in question.  Much earlier, the biblical archaeologist Theodore F. Wright wrote

Child-sacrifice was a practice of the land, and Israel was adopting it
in the worship of Molech. Later it became the usage also in Judah
under Ahaz (2 Kings I6: 3). The belief in its efficacy is shown in 2
Kings 3:27, when the Moabite king openly sacrificed his eldest son,
and thereby sent his victorious enemies home in fear and shame. The
danger of the rite being introduced is seen from Lev. 20: 2-5. With
accumulating evidence of the prevalence of the rite, we shall probably
be led to see an instance of it in the case of Jericho, the foundation
stones being laid with burial jars beneath them... the jar under the
beginning of the wall containing the body of Hiel's eldest son, and
that under the last gate the body of his youngest son.

Such interpretations are challenged on the grounds that burial jars were used in the case of natural deaths as well as human sacrifices. In addition it makes little sense that Hiel would consciously sacrifice his sons in order to fulfill the curse.  This reasoning tends to support the interpretation that their deaths were accidental.
Conclusion: In the end, the answer to the question boils down to a matter of opinion. If they were indeed Ahab's sons, then they were almost certainly sacrificed to protect Hiel from the curse. If they were Hiel's sons, then accidental death is more likely but not certain.


Calculating the length of a single edge in QGIS

Question: I need the correct length of a edge between to points(yellow line in the picture below) in the unit [m] for validation of an equation. I just found the possbility to add geometry (length) to the attribute table of the tracks, but the lengths which I get by adding this column to the attribute table doesn't make sense.
Comment: Is your line layer in a projected coordinate system which uses meters as units? You can check this by accessing the layer's properties and looking for the CRS.
Comment: Doesn't make sense as in ... ?
Comment: Its in WGS 84. Where can I check which unit is in this CRS used? Or even where can I found the unit for WGS 84 ?
Answer: You can find out the units of a layer's CRS by looking at the Information tab in the layer properties window. The CRS WGS84 Geographic (EPSG:4326) has degrees as its unit.

To make length calculations in units that make sense, do the calculation in a CRS that uses the length unit you want to use. In the Field Calculator, you can do this in two ways:
Method One:
Set your project units to the units you want. Project menu > Properties > General. For example, you can see that my project is set to measure distance in miles, and area in acres.

In the Field Calculator, use the $length function to calculate line length using the units you just set in the project settings. Notice that the description for the $length function says:

The length calculated by this function respects both the current project's ellipsoid setting and distance unit settings.

Method Two:
In the Field Calculator, use the transform() and length() functions to calculate length in a different CRS. Substitute the EPSG code of an appropriate equidistant CRS into the following expression:
length(transform($geometry, 'EPSG:4326', 'insert target EPSG code here')

Notice that the description for the length() function says:

Calculations are always planimetric in the Spatial Reference System (SRS) of this geometry, and the units of the returned length will match the units for the SRS.

So if you use this expression in the Field Calculator, `length($geometry), it will calculate length in whatever units the layer's CRS uses.
Notes:

Spatial Reference System (SRS) and Coordinate Reference System (CRS) mean basically the same thing.
Method one is easier than method two. Use method two if you want to compare the length differences between different CRS, or if you don't want to change your project settings. Otherwise use method one.


Delete part of an imported obj model in Blender?

Question: I've made a model in Magicavoxel and exported it in obj format. I then import it to Blender to change pivot point. My problem is that i have to export it from Blender in two parts. My question is how do i delete a part of an obj import?
Comment: The same way you delete a part of any mesh. Which part of the workflow are you having difficulties with?
Comment: Ok thanks but i have almost no experience of Blender and have no clue yet how to delete anything the way i want to. But i'm going through tutorials from absolute scratch and i feel it will take some time until i reach the knowledge i need. I am in a bit of a hurry ;)
Answer: Is the meshed separated in group for OBJ file?
Try to use Split by Group in importing OBJ file:

In that way, the object can be imported separately if the OBJ use group for objects.
Just delete the object by X
If the Object is still joined
Enter edit mode and deselect all vertices alt+A, and hover on the main structure and press L for linked mesh. Revert your selected by Ctrl+I and delete those vertices.
Comment: Thanks! Both of these suggestions worked! I belive i have to stick with importing the parts seperatly to Blender to be able to keep the textures created in Magicavoxel. What do you think? Is there any way i can keep the textures of the part i am exporting from blender?


Are there any varieties of Elephant Ear that are hardy enough to withstand a zone 6b winter?

Question: When I look at Elephant Ear varieties in plant catalogs, they all say Elephant Ears are hardy in zones 9-10, sometimes 7-10. But I see people in my area, zone 6b, growing them outdoors without winter protection. Are they growing special varieties or are most catalogs being overly safe?
Answer: You're on the cusp of being able to overwinter some varieties of Elephant Ear, Colocasia. I found what you did, that of the very cold hardy varieties, zone 7 is pretty much the lowest advertised.
However, there is one variety that keeps coming up as being hardy enough for you. As Tim said, it's the Colocasia 'Pink China'. A number of nursery catalogs and anecdotal articles recommend it as the one to try in zone 6. I even found a few that have grown it successfully in zone 5.
Here's a sampling from my research. Some are redundant, and are listed just to give examples.
Cool Colocasias, Elephant Ears for the Garden, from Plant Delights Nursery in Raleigh, North Carolina, is a great resource for care of Colocasias in general, and features a comprehensive list of different varieties with pictures.

Colocasia esculenta 'Pink China' is an introduction from Kentucky's Brian Williams, and has been the hardiest elephant ear in his trials, with tubers left on top of the ground surviving outdoors in Kentucky. We have heard unverified reports of hardiness in warmer Zone 5, but we'll believe it when we see temperature documentation. Regardless of the hardiness, Colocasia 'Pink China' makes an attractive 4' tall clump that spreads rapidly by rhizomes to create a large patch. The green leaves are held atop mauvy-pink stems. (Hardiness Zone 6-10)

Colosiaplants.com is also a good general resource. From the detailed section on overwintering:

Most Colocasia has a solid USDA Hardiness Zone 7b, while Colocasia 'Pink China' is reportedly winter hardy to Zone 6.

Knollwood Gardens in Ohio:

Colocasia 'Pink China'
A very pretty variety with vibrant pink stems, it grows to 4-6 feet. It is a fairly cold-hardy variety to Zone 6 (we are Zone 5 in most cases).

The Manchester Garden Club in Indiana includes it with other plants on their page called "Hardy Tropicals for Zone 5"

Colocasia Esculenta Pink China
This elephant ear is reportedly as hardy as Musa Basjoo (the Japaneses Fiber Bannana) and it looks great planted under the banana tree. The plant has medium green leaves, but it is easily identified by the pink dot in the center of the leaves. The stems also are very pink in color at times, but not quite so bold at other times.  The tubers spread like crazy and one plant may easily turn into 25 in one summer.
This is a must have for anyone trying to grow tropicals in cold zones. It has easily survived several Zone 5 winters here with no protection, although the survivors don't tend to get quite as big as the ones overwintered in a garage, which can achieve 5 to 7 feet in height. This elephant ear really multiplies in the sun, but it will do just fine in part shade and actually have better color.

Logee's Nursery in Connecticut.

Elephant Ear 'Pink China' (Colocasia hybrid) has brilliant pink stems and rich green leaves with a pink dot in the center to add vibrant color to any container or garden. Possibly the hardiest of all colocasias, 'Pink China' can tolerate zone 6 with a heavy layer of mulch as winter protection. It makes the perfect tropical plant for people in colder zones who don't want to move plants inside for the winter. 'Pink China' generally reaches 4' tall the first season and it spreads by underground rhizomes creating a larger display with each subsequent year.

The Wholesale Elephant's Ears catalogue, in California

Elephant Ears Colocasia Esculenta "Pink China" is known to be the hardiest Elephant Ear variety. With proper mulching, it can even thrive in zone 6. Pink China has dusty green leaves and gorgeous shocking bright pink stems. The pinkish purple hues extend to the under side of some leaves.

Although I'm on the East Coast of the United States, I live in pretty much the same zone as you, and we sometimes have unusually mild winters. I imagine you do too, so if you're willing to take a risk, I'd try this lovely looking variety. If you start to see too many dying off, you can dig up some of the tubers (rhizomes) and move them inside the garage or house (if the plant's not too big) for the winter. According to most of what I've read, transplanting is not too difficult, especially among the smaller varieties.
Click on pictures for larger view.
 Source
 Source
Answer: The Pink China Elephant Ear is supposed to be hardy to zone 6. I have not grown it myself though.
Comment: Hi Tim! I just noticed that this reference links to a removed page. I was going to switch it for you but didn't know what you'd pick.
Comment: @Sue Feel free to use your best judgement. Looks like you linked to a google image search in your answer. I'm not sure what the right thing to do is for something like this, for stack exchange.
Comment: I replaced it with one I used in my answer. It has a picture, care information, and lists it as hardy to zone 6. It's probably similar to the one you had before.


Uploaded Assets always get 600 File Permission and are therefore not displayed (403 Error)

Question: After a fresh manual Craft CMS install everything runs fine, except uploading Assets. Well, the uploading part works fine but uploaded assets always just get file permissions of 600 (adfrw) Group and User are set correctly. Tried it with a fresh install at 2 different hosts still they always get the same permissions.
Does anyone have any idea of what's the problem?
Answer: I just missed the "Assets in this volume have public URLs" lightswitch while setting up the volume :)
Comment: To add to this, I've found that enabling this switch DOESN'T fix the permissions for previously uploaded files (you still get a 403 accessing these) - but those uploaded after this is set are fine.  Threw me out as changing this setting didn't seem to help until I tried uploading a new file!


Is the category of hypergraphs cartesian-closed?

Question: If $H_i = (V_i, E_i)$ for $i=1,2$ are hypergraphs then a map $f:V_1\to V_2$ is said to be a hypergraph homomorphism if $f(e_1)\in E_2$ for all $e_1\in E_1$. Hypergraphs together with hypergraph homomorphisms form a category. Is this category cartesian closed?
Comment: Do you have a hypergraph structure on $Hom(G_1,G_2)$ in mind? Maybe something drawn from category theory (since graphs are kinda like categories)?
Comment: I take that previous link to suggest that the cartesian product on directed graphs makes it cartesian closed. There's also a cartesian product on graphs (link below) but I do not know if hom-tensor duality is satisfied. There's also a tensor product on graphs (link below): https://en.wikipedia.org/wiki/Cartesian_product_of_graphs, https://math.stackexchange.com/questions/302147/definition-of-tensor-product-of-graphs
Comment: I remember from a course in grad school that there are 4 monoidal products on Graph, but I don't remember all of them.
Comment: Good point. How is it done in the category of graphs? Maybe for the category of graphs we could say that $f,g\in \text{Hom}(G,H)$ form an edge if $\{f(v),g(v)\}\in E(H)$ for all $v\in V(G)$. Analogously for hypergraphs, how about ${\cal S}\subseteq\text{Hom}(H_1, H_2)$ is a hyperedge in $\text{Hom}(H_1,H_2)$, iff $\{f(v): f\in {\cal S}\} \in E(H_2)$ for all $v\in V(H_1)$?
Comment: In this link it says Cat is cartesian closed, with functor categories as the internal hom. It says directed graphs are cartesian closed, probably using the same idea. https://en.wikipedia.org/wiki/Cartesian_closed_category
Comment: Thanks @DavidWhite, I think the tensor product ( https://en.wikipedia.org/wiki/Tensor_product_of_graphsis ) the categorical product in the category of graphs
Answer: I think the answer is yes, although the internal-hom may be a little surprising.
First let's describe the cartesian product.  I believe the category $\rm HyGph$ is a topological concrete category over $\rm Set$, in the following way.  Suppose $X$ is a set and $\{S_i\}$ is a family of hypergraphs, with functions $f_i : X \to V_{S_i}$ to their vertex sets.  Then there is a "largest hypergraph" on $X$ rendering the $f_i$ homomorphisms, where $E_X$ consists of all subsets $e\subseteq X$ such that $f_i(e)\in E_{S_i}$ for all $i$.  In particular, given hypergraphs $Y,Z$, if we take $X = V_Y \times V_Z$ with the $f$'s the projections, we obtain the product hypergraph structure on $V_Y\times V_Z = V_{Y\times Z}$: thus $E_{Y\times Z}$ consists of all subsets $e\subseteq V_Y\times V_Z$ such that $\pi_1(e)\in E_Y$ and $\pi_2(e)\in E_Z$.  Put differently, each edge of $Y\times Z$ is obtained by choosing an edge $e_Y\in E_Y$ and an edge $e_Z\in E_Z$, and then choosing a subset of the rectangle $e_Y \times e_Z \subseteq V_Y \times V_Z$ that projects onto both $e_Y$ and $e_Z$, i.e. contains at least one ordered pair with each possible first coordinate and at least one ordered pair with each possible second component.
Now there is a standard way to discover what an internal-hom must look like if it exists, by mapping out of small objects.  To start with, let $I$ be the hypergraph with one vertex and no edges.  Then for any hypergraph $X=(V_X,E_X)$, a homomorphism $I\to X$ simply picks out a vertex of $X$.  Thus, if there is an internal-hom $Y^X$, the vertices of $Y^X$ are in bijection with the homomorphisms $I\to Y^X$, which must in turn be in bijection with the homomorphisms $I\times X\to Y$.  But since $I$ has no edges, the above description of the product means that $I\times X$ has no edges either (in fact we could see this simply because any edge of $I\times X$ must project to an edge of $I$).  Thus every set-function from $V_{I\times X} \cong V_X$ to $V_Y$ determines a vertex of $Y^X$, whether or not it is a homomorphism.
The information about homomorphisms is instead carried by the unary edges (edges containing only one vertex).  The terminal hypergraph $1$ is a one-element set with the unique possible (unary) edge.  A homomorphism $1\to X$ picks out a vertex of $X$ that belong to a unary edge.  Thus, a homomorphism $1\to Y^X$ picks out such a vertex of $Y^X$, but such homomorphisms must be bijective to homomorphisms $1\times X \to Y$, i.e. $X\to Y$ since $1\times X \cong X$.  So the vertices of $Y^X$ are the arbitrary set-functions $V_X\to V_Y$, while the homomorphisms are the set-functions that belong to unary edges.  This is similar to some other examples of cartesian closed categories, such as $G\text{-}\rm Set$ in which the elements of $Y^X$ are arbitrary functions $X\to Y$, with $G$ acting by conjugation, so that the actual $G$-equivariant maps $X\to Y$ (the "real morphisms" in the category) are instead the $G$-fixed-points of the $G$-set $Y^X$.
We can detect all the other edges of $Y^X$ in a similar way.  For any nonempty set $A$, let $J_A$ be the hypergraph with vertices $A$ and the only edge being the whole set $A$.  Then a homomorphism $J_A\to X$ is a function $A\to X$ whose image is an edge.  Thus, an edge of $Y^X$ must be uniquely determined by picking a subset $A\subseteq V_{Y^X}$ of functions $V_X\to V_Y$ such that the corresponding function $A\times V_X \to V_Y$ is a homomorphism $J_A \times X\to Y$, which is to say such that for any edge $e_X\in E_X$, if a subset $e\subseteq A\times e_X$ projects onto both $A$ and $e_X$, then $\{ f(x) \mid (f,x)\in e \}$ is an edge of $Y$.
This defines a hypergraph $Y^X$ which must be the cartesian-closed exponential if such exists.  It remains to prove that it actually is, but I think this is fairly straightforward.  The evaluation map $Y^X\times X\to Y$ is a homomorphism, essentially by definition of the edges of $Y^X$.  And if $Z\times X\to Y$ is a homomorphism, then there is a unique induced function $V_Z\to V_{Y^X} = (V_Y)^{V_X}$, which is a homomorphism again essentially by definition of the edges of $Y^X$.


Ninject contextual binding magic

Question: I have a bit of a strange situation with regard to my bindings.
I have a few event sources, and classes that want to subscribe to them. I'll have different instances of the sources (although they will all be the same classes), but the types of the subscribers might change between different classes.
My approach so far is something like this:
public interface ISubscribeTo<T> where T : ISubscribable
{
  void Subscribe(T eventSource);
}

public interface ISubscribable {}

I want to have any type that is an ISubscribeTo<T> have an instance of the ISubscribable passed through to it on activation.
This is pretty trivial when I use an ActivationStrategy to wire these things up.
The complication I have is that the ISubscribeTo<T>s vary depending on what class I'm activating.
In my ActivationStrategy, I have a call into the kernel's GetAll method, but I'd like to somehow only get instances that are already activated for the request.
Does anyone have any suggestions about how I can achieve this?
Answer: Have a look at the event brokers. They make it very easy to subscribe to events from other components without adding an own mechanism. See the tutorial
https://github.com/ninject/ninject.extensions.bbveventbroker

Ninject contextual binding magic


MATLAB - Global optimization toolbox

Question: When I run the GA solver, I got the following warning: What does it mean? What action should I take or I just ignore it?
Warning: Length of upper bounds is > length(x); ignoring extra bounds.
Answer: It means you have specified more upperbounds ub(i) than the number of unknown variables, nvars. The extra ub(i) will be ignored by GA.

MATLAB - Global optimization toolbox


Why can electron app be published on MAC App Store?

Question: According to this guideline, electron app can be published to MAC App Store. Electron itself is based on chromium and node.js, and they are both based on v8 js engine which enables JIT. But JIT compiler is not allowed by MAC App Store as far as I know. So how can it bypass this limitation?
Answer: It's not against Apple's Developer Program guidelines as long as the binary remains the same and the app continues working as advertised in the store.
https://developer.apple.com/programs/information/Apple_Developer_Program_Information_8_12_15.pdf

3.3.2 Except as set forth in the next paragraph, an Application may not download or install executable code. Interpreted code may only be
used in an Application if all scripts, code and interpreters are
packaged in the Application and not downloaded. The only exceptions to
the foregoing are scripts and code downloaded and run by Apple's
built-in WebKit framework or JavascriptCore, provided that such
scripts and code do not change the primary purpose of the Application
by providing features or functionality that are inconsistent with the
intended and advertised purpose of the Application as submitted to the
App Store.
For OS X Applications submitted to Apple for distribution
on the App Store, an Application may install or run interpreted or
executable code (e.g., plug-ins and extensions) for use in conjunction
with the Application only so long as such code: (a) does not change
the Application's submitted binary or would not otherwise be
considered an update (as determined in Apple's sole discretion); and
(b) does not change the primary purpose of the Application by
providing features or functionality that are inconsistent with the
intended and advertised purpose of the Application as submitted to the
App Store.
Comment: Is it not against Apple's sandbox? I have thought chrome for ios can not embed v8 because v8's JIT violate Apple's sandbox limitation.
Comment: If I develop a Mac App which embeds v8 as it's js engine, Can the App be allowed by App Store to download js code and execute it during App running, just like react native does (see [https://github.com/Microsoft/react-native-code-push](https://github.com/Microsoft/react-native-code-push))? What if the App choose javascriptcore instead of v8?
Comment: iOS does not allow JIT compilation by third-party apps (like V8). MacOS does (and V8 runs there, as part of Electron or Chrome or on its own or in other embedders).


Python shelve having items that aren't listed

Question: I've been saving a bunch of dictionaries to file using Python's shelve module (with Python 3.4 on OSX 10.9.5). Each key is a string of an int (e.g., "84554"), and each value is a dictionary of dictionaries of a few smallish strings.
No keys are used twice, and I know the total superset of all possible keys. I am adding these key-value pairs to the shelf via threads and which keys/values are added changes each time I run it (which is expected).
The problem I've been having is that the number of keys iterable/visible with shelve's shelf.keys() and the number of unique keys for which key in shelf.keys() are different.
Here's my code. I first initialize things and load ids, which is the list of all possible keys.
import shelve
from custom_code import *
MAIN_PATH = "/Users/myname/project_path/src/"
ids = list(set(load_list(MAIN_PATH + "id_list.pkl")))
c = c2 = 0
good_keys = []
bad_keys = []

I then open the shelf, counting all the number of keys that I iterate through with db.keys(), adding the "good" keys to a list.
db = shelve.open(MAIN_PATH + "first_3")
for k in db.keys():
    c2+=1
    good_keys+=[k]

Then, I check each possible key to see if it's in the shelf, checking to see if it exists in the shelf, and doing the same thing as above.
for j in set(ids):
    if j in db.keys():
        c+=1
        bad_keys+=[j]

The two counters, c and c2, should be the same, but doing:
print("With `db.keys()`: {0}, with verifying from the list: {1}".format(c2, c))

yields:
With `db.keys()`: 628, with verifying from the list: 669

I then look at keys that were in bad_keys but not good_keys (i.e., collected from db.keys()) and pick an example.
odd_men_out = list( set(bad_keys).difference( set(good_keys) ) )
bad_key = odd_men_out[0]
print(bad_key) # '84554'

I then check the following:
print(bad_key in db.keys()) # True
print(bad_key in db)  # True
print(db[bad_key]) # A dictionary of dictionaries that wraps ~12ish lines
print(bad_key in list(db.keys())) # False

Note that last check.  Does anybody know what gives?  I thought shelves was supposed to be easy, but it's been giving me complete hell.
Perhaps unrelatedly (but perhaps not), when I let an even greater number of entries accumulate in the shelf and try to do something like for k in db.keys() or list(db.keys()), I get the following error:
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/_collections_abc.py", line 482, in __iter__
    yield from self._mapping
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/shelve.py", line 95, in __iter__
    for k in self.dict.keys():
SystemError: Negative size passed to PyBytes_FromStringAndSize

But can still access the data by trying all possible keys. Evidently that's because I'm not using gdbm?
Comment: Possibly related python [bug report](https://bugs.python.org/issue33074)
Answer: When I tried to save some numpy arrays with more than 1000 elements in my shelf it would only save some and completely skip others, without generating an error.
Apparently this is an issue when using Shelve in Mac OSX (here are some bug reports (https://bugs.python.org/issue33074 , https://bugs.python.org/issue30388).
The only easy solution I found was to use Pickle instead of Shelve.


cache setting in grails

Question: My DataSource Config:
hibernate {
 cache.use_second_level_cache = true
 cache.use_query_cache = true
 cache.provider_class='org.hibernate.cache.EhCacheProvider'
}

i have an entity named Category that can have one or more Categories (children)
class Category{
 int ordering
 static hasMany = [categories: Category]

 static mapping = {
    categories(sort: "ordering", order: "asc")
    sort "ordering"
    cache usage: 'nonstrict-read-write'
    categories cache: 'nonstrict-read-write'
}

When i change a property from the admin page, lets say the ordering property from a category instance, that change is not reflected from the association to the parent category, so the assoc collection has the old property for the altered child.
I tried to remove this:
  categories cache: 'nonstrict-read-write'

and then the categories assoc is always up to dated.
How can i ensure that every time i update a category instance, the categories assoc for the parent category will be informed with the changes? Shouldnt be worked like this by default??
Answer: ok i found it!
i had to evict the entire collection like this:
      sessionFactory.evictCollection(Category.class.name + '.categories')

cache setting in grails


Is Libertarianism in favor of intellectual property rights?

Question: Related to this question on libertarianism on monopolies, how do libertarians in the USA, as represented by the Libertarian Party, view copyright and patent protections?
Comment: Wikipedia seems to have a decent article: https://en.wikipedia.org/wiki/Libertarian_perspectives_on_intellectual_property
Comment: I think its is probably too broad to tackle in a single question.  IP has been intentionally broadened by IP lawyers and corporations that want to protect their interests.  It should probably be broken up into patents, licencing, and creative works (like art and literature)
Comment: This may fall into the bucket answer of "The government is incapable of efficiently tackling this complicated issue and should therefore stay out of it" that many libertarians default to.
Comment: As a would-be libertarian (presumably), why do you need - let alone want - someone to decide this for you? Make up your own mind on the topic yourself.
Comment: What would be interesting follow-up after we see answers is how the topic of patenting things found in nature, or patenting things not originally invented (but used for specific purpose) fall into that.  Ex - Polaroid's successful patent infringement lawsuit against Kodak - Kodak argued that rollers have been around since the caveman, Polaroid argued that they haven't been used to spit a photo out of a camera, so they have a patent on rollers for that purpose.  They won, and Kodak changed policy to become the #1 patent application submitter for years after that.
Comment: Also see [this question](https://politics.stackexchange.com/questions/352/can-copyright-be-interpreted-as-a-liberal-economic-policy/3164)
Comment: I've edited to focus on libertarianism in the USA. This makes it less broad, as answers can focus on the published resources of the Libertarian party.
Answer: Many libertarians consider intellectual property to be artificial rights granted by the state[1,2,3]. They are essentially a state enforced monopoly on the allowable use of an idea or creative work.
A useful litmus test on whether a right is natural or artificial is to consider the right in the absence of a state. Would a society recognize that right if there were no state compelling them to? Could that right be practically enforced in the absence of a state?
With commonly accepted natural rights such as the right to life and the right to property the answers to both these questions is an unqualified "yes". Even before the development of private property (land) around 12000 BC-10000 BC there is a consensus among historians and anthropologists that humans recognized personal property. With intellectual property this is far less likely. To this day a large percentage of the population routinely ignores intellectual property law whenever the opportunity arises.
Without a state could an inventor or content creator insist intellectual property rights be included in contractual arrangements with distributors and retailers of his product? Sure. The question is what incentive would those parties have to engage in such a contract if there are other creative persons who make no such demands?
Of course to have the same reach of the state, any such contract would need to be viral in nature. By which I mean it would need to bind consumers beyond the first sale in perpetuity. Otherwise, even if distributors and retailers agreed to the contract, the consumer, as a third party, would be under no obligation to abide by it.
Contrast this with private property, which has both widespread acceptance and requires little more than a willingness to use force to defend it against trespass.
As for whether the tenets of libertarianism support intellectual property one need only compare intellectual property with those tenets.
Self-ownership
Intellectual property assumes the inventor/creator has the right to control the use of his idea by others. This is at odds with the notion of self-ownership. If individuals are self-owners then the individual has a sole and exclusive right to his own mind and body and by extension, his own actions unless those actions violate the equal rights of other individuals. To claim that the act of copying and/or improving upon someone else's ideas is a violation of that person's rights you would first need to establish that their original creative act resulted in a natural right to prevent others from doing so. This is a tenuous argument at best.
Comment: I'd like it better with a source.


Lightning Email template Related Entity Types not populating

Question: I'm trying to create an email template in lightning. The Related Entity Type dropdown is only loading Contact and lead, not all of the regular objects.
Comment: Try refreshing without Cache, that should do the trick.
Comment: I tried that but no change. I also tried a new browser and that didn't change anything either.
Answer: I had the same issue. My custom object was correct with Activities allowed and "Enhanced Email" setting was enabled. Remove cookies didn't fix.
What finally worked was to disable Enhanced Email and enable it back. My custom object (and a full bunch of others) instantly appeared in the picklist. I was in a sandbox created after the Enhanced Email was activated in the production instance, but there was no Lightning template created yet.
Answer: I opened a case with Salesforce and the result was that "Enhanced Email" was disabled. This is the fix:
===============
Objects not available under "Related Entity Type" in Lightning email template
https://help.salesforce.com/articleView?id=000349235&language=en_US&mode=1&type=1
However, before you enable this, please review the articles below about Enhanced Email.
Learn about the 'Enhanced Email' and EmailMessage objects
https://help.salesforce.com/articleView?id=000313606&type=1&mode=1
Use Enhanced Email for More Email Functionality
https://help.salesforce.com/articleView?id=sf.emailadmin_enhanced_email_overview.htm&type=5
To enable enhanced email, here are the steps.

Click the gear icon on the upper right side, then click Setup
On the quick find box on the left, type 'Enhanced Email'
Click 'Enable'
Answer: My custom object was correct
Activities allowed and Enhanced Email enabled. Remove the cookies didn't fix.
This worked for me.
Disabled Enhanced Email, re-enable Enhanced Email


What is this "Shared" in Finder's Sidebar?

Question: I don't know what this "Shared" is in the Finder's Sidebar.  Can these other machines access any of my information?  Should I turn this off?
Comment: In the system preferences, everything is unchecked for shared.  And I still see two "other machines" in the shared section of the finder.
Comment: This doesn't mean that they have access to your PC, if everything is turned off. You can disable others to access your information but you can still access theirs, if you have ID and pw.
Answer: System preferences > Sharing
You can choose what to share and with what conditions. You can share files with other devices connected to your network, but they have to know your UserID and password, you can share printers and many other functionalities.
Obviously, you can choose to enable the sharing or not just checking the "services" on the left sidebar. If you disable everything, your "shared" folder will not be accessible.


How to say "and more!" in a more professional sense

Question: We are in the process of writing an ad that details our curriculum, and the ad goes something like this - "...fall prevention, medical emergencies, AND MORE!" I keep thinking there has to be a better way to phrase that instead of "AND MORE!"  Any ideas? Thank you!
Comment: I agree with Jim. "...and more." is totally fine (as long as it's lowercase) in a professional setting, if there are too many items to list conveniently. Additionally, exclamation marks should really only be used for exclamatory sentences (e.g., "Oh my!" "Wow!").
Comment: Yeah, you don't need a synonym, you just need lower case and no exclamation point.
Comment: Hire a copywriter and please don't ask for it for free here. Thank you.
Answer: Personally, I would simply use "etc.", short for et cetera (Latin, from et "and" and cetera "the rest", neuter plural of ceterus "left over").
Answer: You may use "among others" or "to name a few".
Answer: The expression I would use is etc., which is an abbreviation for et cetera (literally: "and the rest").
The APA blog lists it as one of many "Latin abbreviations common to scholarly writing", so it is accepted (and actually very widespread) in formal writing.
Answer: In answering this question, one needs to consider why the OP's wrote ' . . . AND MORE!' (in all capitals, with an exclamation  point), rather than just ' . . . and more' . I assume that by writing the phrase that way, the OP is trying to convey a certain exuberant tone in which the phrase is often uttered in advertising.
Now, why do advertisers use that tone? Their purpose is twofold. On one side, they want to leave the impression that the additional, unenumerated items contain something exciting and surprising, something that is better than one might expect on the basis of an extrapolation from the enumerated items. The phrase ' . . . AND MORE!' is striving to be intriguing, unlike etc. or and so forth, which suggest that the additional items are so similar to the enumerated ones that listing them all would be boring. On the other side, the advertisers also want to avoid the responsibility that they would be assuming by listing and describing the additional items. The phrase ' . . . AND MORE!' enables them to do that, as it is vague enough that they cannot be accused of false advertising, if the 'more' turns out to be disappointing.
The phrase ' . . . AND MORE!' is thus an advertising device for manipulating one's audience, while avoiding responsibility. This implies that there cannot be an equivalent of that phrase that is suitable for serious, professional/academic writing, because in such writing one is expected to assume full responsibility for one's words, and be candid with one's audience.
The other answers on this page are, of course, correct in saying that something like etc. may be used in professional contexts, but that term does not capture the nuances of ' . . . AND MORE!' that the OP was probably trying to convey by the use of capitals and the exclamation point.


How does hardware RAID handle firmware updates for the underlying drives?

Question: My SuperMicro X13SAE has hardware raid for the three m.2 NVME drives that it supports. My question is how does it handle firmware updates for these drives? If the drives aren't being exposed to the operating system, then I assume fwupdmgr and fwupdtool won't see them as distinct drives. So how does the firmware get updated by default? And what options do you have for updating the firmware short of turning off hardware RAID or plugging the drives in elsewhere?
Comment: *"how to deal with broken hardware?"* seems like two steps before we even get to *"how to deal with broken firmware of that rare sort where the vendor understands, acknowledges and provides proper fixes?"* - how are you keeping track of the devices own health assessment, if not by querying the individual controllers?
Comment: @anx Currently, I run `fwupdmgr update` and it shows all the devices and updates the ones not up to date. I'm not sure what you mean by health assessments, but that's not the question here.
Answer: The NVMe standard specifies a firmware update process. Any NVMe device supporting that process can be updated by a standard routine located in the RAID controller's firmware. The update can be integrated in the general configuration GUI or some extra tool.
See the NVMe Base Specification clause 3.11 for details.
A real hardware RAID controller necessarily and completely abstracts the physical drives from the operating system. The board you've linked uses Intel's Rapid Storage Technology (IRST) however, which actually is only host/firmware RAID - a software RAID with BIOS support, making it bootable but possibly problematic with non-RAID OS drivers. Open-source systems usually ignore host RAID and access the bare disks, breaking RAID synchronization - you might be better off using OS-level software RAID. Depending on the operating system and tools you might also get to the drives directly, but that could interfere with host RAID operation.
Comment: _"The board you've linked [...]  actually is only host/firmware RAID"_ - Which means OP is probably [better off using Linux software raid](https://superuser.com/questions/245928/does-fake-raid-offer-any-advantage-over-software-raid). That also immediately solves the firmware update problems, as then the individual drives are accessible from Linux. Feel free to include that in your answer :)
Comment: I wonder how clever the intel firmware is about the
*"reset me to switch to that firmware slot"* answer. I would not dare trying anything but strictly sequential upgrades.
Comment: @marcelm Host RAID is generally problematic with anything else than Windows, but that's for the user to evaluate once they've recognized that on-board RAID isn't necessarily hardware RAID.
Comment: @Zac67 I agree that's for OP to decide, but you could still point them in that direction. Especially as it actually answers the question OP had (how to update firmware).
Answer: Any decent hardware raid controller will have some type of software to manage the underlying drives. My Adaptec ASR71605 raid controller, for example, uses the maxView Storage Manager.
From there, I can simply click the device in question, then click "firmware update" in the GUI. I haven't tried it while the device is in use, but since I have parity in the array the worst case scenario is that it would need rebuilt after the firmware update. I would still make sure to have an up-to-date backup before modifying firmware though.
I'm on Windows, but the tool's website says it supports "Windows, Linux, VMWare, and Solaris", which is pretty typical for these kinds of devices.


Chemical bond-covalent-valence electrons OH-

Question: I would like to ask how many valence electrons took part in creating chemical bond in $\ce{OH-}$? Is the minus related to $\ce{O}$ or to $\ce{H}$? Are there any spare valence electrons which didnt take part in creating chemical bond in $\ce{OH-}$?
Answer:
In the photo the orange electrons are non bond electrons.
And the black electrons are bond electrons.
There are 2 electrons took part in creating chemical bond in $\ce{OH}$.
The first one is from oxygen.
The second is from hydrogen.
This kind of bond is called "Covalent bond".
For more about Covalent bond :
https://en.wikipedia.org/wiki/Covalent_bond
The minus is  related to  the black and white electrons that are free (in Oxygen).
The white electron is come from other element.


LDAP on non-Server OSX

Question: I have read where Apple plans to stop making OSX server.  What does this mean for LDAP services?  Is it possible to install LDAP on a regular mac running High Sierra? Could my own iMac be the LDAP server for my organization in other words?
Answer: macOS Server is keeping LDAP with no published plans for it to be removed. See:

Prepare for changes to macOS Server - Apple Support
Answer: To answer the question(s)

Is it possible to install LDAP on a regular mac running High Sierra?

and

Could my own iMac be the LDAP server for my organization in other
  words?

Yes on both counts, though I wouldn't put LDAP server on a production workstation (if you turn off your iMac, LDAP goes down for everyone)  You could put it on a Mac mini (two would be better) and let it run as server 24/7.
LDAP is just a service much like SSH, Apache, or DHCP.  You don't need a server version of an OS to run a server instance.
OpenLDAP is available via Homebrew and you can run this on your plain macOS machine.
That said (non-Apple solution follows) I probably wouldn't run LDAP on a Mac - it's just too expensive (hardware wise).  I would get two cheap PCs, load up FreeBSD (what Mac is based on) and fire up OpenLDAP on each.
Comment: This is happy news.  My thought was to get two mac mini's (we have a few at hand already) and have them run High Sierra (not server) and have them run LDAP in kind of a load balanced or at least master/slave kind of way.  Can you recommend any articles on setting them up?
Comment: The best one I know of is from the [FreeBSD manual](https://www.freebsd.org/doc/en/articles/ldap-auth/ldap.html)  It should follow the setup for Mac, but I personally haven't tested it.  At the very minimum, it's a good primer

LDAP on non-Server OSX


Nominal or Ordinal

Question: When looking at a statistics hypotheses such as, Suicide will be supported when faced with a terminal illness just at letting one die?  When looking at surveys it was a yes/no question.  Does this make suicide and letting one die both nominal since there is no order to the question?  I am tying to figure out which formula to use in a cross tabulation that will give the most accurate level of association lambda, gamma, and Person's r. But need to know if I am looking at nominal or ordinal?
Answer: To clarify, does the outcome have exactly two alternative values? If not, what are the values and do they take a meaningful order? If it's just two values, it doesn't matter whether they have an order, since you'll only be comparing one to the other somehow.
Second, with what kind of variable(s) are you cross-tabulating the outcome? Nominal? Ordinal (with three or more values)? Continuous?
Comment: What I am trying to discover is the strength of association between chosen variables as well as how to interpret the findings using SPSS functions and tests such as lambda, gamma, and Person's r along with other possible tests.  I have the let die as my IV and suicide as my DV when I complete the cross tabulations.  But I can not figure out which test would give me the best interpretation of the findings.
Comment: I really don't understand the data from your description. It sounds like you asked people whether, given (someone's terminal illness), would they let the person die naturally or support suicide? Is that true? In this case, the outcome is a variable with two values: die naturally or support suicide.

When you say cross-tabulations, what are the other variables? Like, maybe, age of respondent, sex of respondent. What are they?

Forget the tests for the moment and describe the data.

Nominal or Ordinal


possible cause for the water heater being unable to be lighted

Question: The water heater could not be lighted. I tried several times without being successful. What could be the possible causes for the water heater to fail to be lighted. This water heater is only 1 and half years old.
Comment: Make and model would be helpful here as well a description of what you tried to do light it, any error codes, etc. Without this basic information, any answers will be very generalized.
Comment: Also, what caused it to go out in the first place? Did you shut it off? Did it go out on its own? Did the gas company shut off your supply temporarily for some reason?
Answer: There are one user failure and 2 equipment fails that usually contribute to non lighting water heaters"
User
Not pressing down the pilot button long enough.  After lighting the pilot flame initially, you must hold down the pilot button long enough (30 seconds) to allow the thermocouple (a detector of heat, which sents its signal to the main gas valve) to heat up enough.
Equipment

Thermocouple is broken or misadjusted so that the pilot flame dosen't heat it.
Main gas valve broken.  This must be replaced as there are no 'user serviceable parts' inside.