Can we update links to BrewAdvice?

Question: There are comments / links in older posts from BrewAdvice that link to the wrong ID on the current site. Is there a way to update these programmatically, or do we have to go in and fix them ourselves?
Example: Immersion chiller or counter-flow chiller?
Answer: Below are a list of posts / comments that have a link to BrewAdvice.com - there's no great way of automatically linking these so the effort will be manual

https://homebrew.stackexchange.com/questions/658    post
https://homebrew.stackexchange.com/questions/797    post
https://homebrew.stackexchange.com/questions/847    comment
https://homebrew.stackexchange.com/questions/864    comment
What's the difference between primary & secondary fermentation?    post
https://homebrew.stackexchange.com/questions/898    post
https://homebrew.stackexchange.com/questions/915    post

Storing bottle conditioned beers and carbonation    comment
https://homebrew.stackexchange.com/questions/981    comment

https://homebrew.stackexchange.com/questions/981    post
https://homebrew.stackexchange.com/questions/1000   post
https://homebrew.stackexchange.com/questions/1119   post
https://homebrew.stackexchange.com/questions/1155   post
https://homebrew.stackexchange.com/questions/1188   post

https://homebrew.stackexchange.com/questions/1213   comment
https://homebrew.stackexchange.com/questions/1215   comment

https://homebrew.stackexchange.com/questions/1239   post

Wet Crushing Grain   comment

https://homebrew.stackexchange.com/questions/1273   post
https://homebrew.stackexchange.com/questions/1281   post

Gelatin for clearer beer   comment
https://homebrew.stackexchange.com/questions/1311   post
Small Space & Apartment Brewing: Equipment Storage   post
Small Space & Apartment Brewing: Mashing   post
Small Space & Apartment Brewing: Steeping   post
Small Space & Apartment Brewing: Boiling   post
Small Space & Apartment Brewing: The Chill   post
Small Space & Apartment Brewing: Fermentation   post
Small Space & Apartment Brewing: Packaging   post
Small Space & Apartment Brewing: Cellaring   post
https://homebrew.stackexchange.com/questions/1344   post
https://homebrew.stackexchange.com/questions/1350   post
Beer Pairing: Stuffed Shells with Tomato Sauce   comment
https://homebrew.stackexchange.com/questions/1384   post
https://homebrew.stackexchange.com/questions/1423   post
https://homebrew.stackexchange.com/questions/1426   post
Using Grolsch "Premium Lager" bottles for bottling   comment
Massively Over-Carbonated Beer...What Do I Do?   comment
https://homebrew.stackexchange.com/questions/1510   post
https://homebrew.stackexchange.com/questions/1511   comment
Harvesting commercial yeast   post
What is conversion?   post
https://homebrew.stackexchange.com/questions/1541   comment
https://homebrew.stackexchange.com/questions/1543   comment
https://homebrew.stackexchange.com/questions/1553   post
When should I add a vanilla bean?   post
https://homebrew.stackexchange.com/questions/1603   comment
Improving Your Brewing Significantly   comment
Improving Your Brewing Significantly   post
https://homebrew.stackexchange.com/questions/1625   post
https://homebrew.stackexchange.com/questions/1672   post
https://homebrew.stackexchange.com/questions/1689   post
Would/Could you add boiled, rehydrated extract after wort is cooled & topped off to boost OG?   post
https://homebrew.stackexchange.com/questions/1712   post
https://homebrew.stackexchange.com/questions/1721   comment
https://homebrew.stackexchange.com/questions/1760   post
https://homebrew.stackexchange.com/questions/1771   post
https://homebrew.stackexchange.com/questions/1784   post
https://homebrew.stackexchange.com/questions/1795   comment
https://homebrew.stackexchange.com/questions/1797   post
Why is it bad to pitch too much yeast?   post
Why is it bad to pitch too little yeast?   post
How do you filter at home?   post
https://homebrew.stackexchange.com/questions/1831   post
https://homebrew.stackexchange.com/questions/1855   post
https://homebrew.stackexchange.com/questions/1898   post
Using commercial (breakfast) cereals in a mash   post
https://homebrew.stackexchange.com/questions/1985   post
Detriment of gelatin fining on flavor or aroma   post
https://homebrew.stackexchange.com/questions/2052   comment
https://homebrew.stackexchange.com/questions/2063   comment
https://homebrew.stackexchange.com/questions/2067   post
https://homebrew.stackexchange.com/questions/2088   post
why do you degas wine but not beer?   post
https://homebrew.stackexchange.com/questions/2133   post
https://homebrew.stackexchange.com/questions/2142   post
Bottling kegged beer   comment
https://homebrew.stackexchange.com/questions/2192   post
Didn't hit gravity--how to calculate how much malt extract to add to the fermenter?   comment
https://homebrew.stackexchange.com/questions/2232   post
https://homebrew.stackexchange.com/questions/2236   comment
Calculating sugar in fresh fruit   comment
Shipping beer to fellow brewers   comment
Drying freshly picked hops   post
Using force carbing, how long does 5 lbs CO2 last you?   comment
Ported carboy vs. siphoning?   comment
Preparing Cherries for Secondary   post
Pumpkin Spiced beer   comment
Capturing wild yeasts?   comment
Too much Irish moss?   post
https://homebrew.stackexchange.com/questions/2567   comment
https://homebrew.stackexchange.com/questions/2620   comment
Comment: I'm going to start doing these and crossing them off the list. Any other admins, please lend a hand.
Comment: @PJ would it be helpful for those of us without edit access to help out too?  Is it easier for you to approve an edit than actually editing?
Comment: @PJ All posts up through ID 1300 (not comments) are done (currently as suggested-edits). Can you wikify this? I don't have the option to edit it.
Answer: I'm a moderator at tex.stackexchange.com and we always do that by hand. I'm not aware of any scripting or other solution which would avoid that and don't think there is any.

Can we update links to BrewAdvice?


Ideal chain / entropic spring - what is the *microscopic* force?

Question: The ideal chain is the classic example of an entropic force. Usually one derives this force from the fundamental relation describing forces in the canonical ensemble:
$$
\tag 1
F = (\partial \langle E \rangle / \partial x)_T - T (\partial S / \partial x)_T
$$
where $x$ is the length of the chain.
The first term is identified as ordinary force, and the second as entropic force. The definition of the ideal chain makes the energy $E$ constant for all configurations, and so there is no ordinary force. Yet, the entropy $S$ for a given $x$ varies (see the wikipedia article for why this is so), so there is an entropic force and we are told this is found to agree reasonably well with experiments.
There is an important connection with ideal gases. If we apply (1) to an ideal gas, with volume in place of $x$, the pressure of an ideal gas is seen to also be an entropic force, since its $\langle E \rangle$ is proportional to $T$ but independent of volume. So there is a strong analogy between stretching a rubber band (made of polymers sort of like ideal chains), and compressing an gas (made of molecules sort of like ideal gas particles).
However I have a doubt about the ideal chain model, that there is no apparent microscopic force acting in the ideal chain. Afer all, the same thermodynamic force can be written equivalently as:
$$
\tag 2
F = (\partial \langle E \rangle / \partial x)_S
$$
In an ideal gas, this expression of the force corresponds to to the microscopic picture of adiabatically changing the volume under the influence of molecules randomly pounding on its surface. Each time the boundary is moved inwards, there is a chance that a molecule is in the process of colliding with the wall and so the moving wall gives energy to the molecule. In this way when entropy is held constant, the energy of an ideal gas does change with volume.
The problem is that in an ideal chain, it seems impossible to understand the force using (2). We are told the energy is supposed to be constant which lets is ignore the first term in (1) but this would produce zero force in (2)! Analogizing to the ideal gas, there must be a microscopic force in a chain that is randomly pulling against the end of the chain, such that (2) agrees with (1), but what is it?
I have a strong suspicion about the solution, which I will add as an Answer below.
Answer: The missing piece is the inertia of the chain links. In other words, the ideal chain model only examines possibilities over the configurational coordinates of the chain's phase space, and completely neglects the momentum coordinates. In this sense the ideal chain model is not a real statistical mechanical calculation, since it does not integrate over the real mechanical phase space.
We would face the same situation with the ideal gas if we calculated entropy of the ideal gas based only on where the atoms could be, and not how fast they could be moving. It would give an incorrect expression for entropy, like $k \ln V$ per molecule, missing several additive terms also dependent on mass and temperature. Using (1) this would lead to the correct expression for pressure ($kT/V$ per molecule), but we would fail to see in (2) where the force comes from microscopically.
In the same way, the reason the ideal chain gets away with neglecting the chain links' momentum is that it cheats and produces the wrong entropy missing many terms, yet this entropy does have the correct value of $(\partial S/\partial x)_T$. Anyway, this answers where the force comes from in the microscopic picture: it is caused by the inertia of the chain links wiggling around randomly, but on average pulling the chain ends together. When the chain ends are moved inwards, on average the chain at that time will be moving in such a way that its motion is accelerated by the changing end positions.
(An aside: If this what is going on, why is this not mentioned in the many articles I've seen that discuss the entropic spring? I think it's good to have both micro and macro pictures.)
I wonder though, whether it's true that including inertia would produce the exact same force. After all, the chain links are rigidly fixed and so all of their speeds are somehow correlated with each other.


Google Earth Engine Limiting Image Values

Question: I'm using Google Earth Engine's Javascript API to process Sentinel-2 images from 2016-2021. I've calculated the EVI values for these images, which has a range of -1 to 1. I want to correct any anomalous pixels that fall outside of their range by enforcing -1 as the minimum value possible and 1 as the maximum possible value. Is there a way to enforce these maximum and minimum values?
Answer: Use <code>.clamp()</code> for that. This will set all values above or below a certain threshold to the threshold you supply to the function. Here's a minimum example:
<code>// Test Image with Values between -1.5 to 1.5
var test = ee.Image.random().multiply(3).subtract(1.5)

var clamped = test.clamp(-1, 1)

Map.addLayer(test, {}, "Values outside -1, 1")
Map.addLayer(clamped, {}, "All values inside -1, 1")
</code>
Alternatively you can also think about masking values outside of your accepted range.


How to protect floor carpet while using office chair?

Question: I installed new carpet and trying to protect it from few office chairs with wheels (in home office setting). Carpet is medium fleck thick. I checked carpet protectors for office chairs, but this solution is expensive for me. Can anyone suggest cheaper way of protecting carpet while using office chairs so that chair can move easily and carpet is also protected.
Comment: Do the chairs have castors?  The answers would be different.
Comment: @Chenmunka yes, the chairs are with castors.
Answer: A certain Scandinavian home goods store sells 100x120cm rigid plastic (PET) floor protectors for €25, which work very well and should be within budget if they're in your area or deliver there, but any plate material that's both rigid and wide enough for chair movements will do.
If you don't have access to the above, you could use a piece of more universally available MDF (which price wise is quite close per m2), triplex will probably also do (although this might be noisier and damage/crack more easily over time). As the drop at the ridge is a lot higher compared to the floor protector above, and your chair might get stuck when it rolls over, you might want to increase the size to, say, 150x200cm, so this doesn't happen. Continuous plate material is strongly preferred for this, any seams would (eventually) be noticeable when you roll over them.
Another  alternative is cutting out a part of the carpet where the wheelchair will be (you can keep it in storage and reinsert later), although this depends on what's underneath it. Some carpet substrates are not well suited for point pressure.
Answer: Merrily, We Roll Along Carpet Hack:
To protect the carpet, use the largest diameter, softest, and widest rollers that your chair can accommodate to spread the load over as much rug area as possible. A five-roller base is preferable to a four-roller one.
This rug-friendly equipped base will take more effort to move around on the rug than any other rollers/casters.
The easiest chairs to move around on the rug will be those with large diameter, hard, roller-blade style casters. The thinner profile of the roller-blade will have less contact area and exert greater pressure on the carpet, which will crush the glued base and underlay fabric of the carpet. The mechanical action will lessen the life of the carpet.
Good Luck.
Answer: Thanks for above answers. I solved the problem putting pieces of carpet underneath the caster chair : I got 12 x 2 feet carpet piece from nearby home improvement store at rate of $0.94/sq feet, cut that big piece into 3 smaller pieces using a utility knife ($5-6 in the same home improvement store), and put the 3 cut pieces under chairs. The carpet pieces on top of floor carpet may not look very pretty, but I found it is economical way to protect floor carpet beneath and chair rolls fairly easily.


Active Directory crashed without backup or failover. Recreating from scratch

Question: My Active Directory server crashed and I do not have a secondary DC, no RAID, no backup and the system disk is completely dead. I know it is bad and stupid to not have a backup but let's leave those discussions to other threads.
The server was domain controller, DNS and file server. The data disks are still working so the file server part is still accessible, including home directory of all users.
I have installed a new need to do the following steps:

Create a new AD (I assume that it should have the same root domain name and same NetBIOS domain name as the lost AD had)
Setup DNS server on the server
Create new accounts for every computer in the network
Create new user accounts for every user (assigning a new password to each and every user)

(Edit #1: more steps)

Rejoin each computer to the new AD

Is it possible to remap old accounts against new ones? We have a source control system (Microsoft TFS) that is linked to our domain accounts (e.g. DOMAIN\user1).
Questions:
 1. Do you have any suggestions to the above scenario?
 2. Is it possible to "remap" new accounts against old ones so that permissions are intact? E.g. TFS permissions.
When everything is up and running I will of course create a backup scheme, including image backup of the server and a secondary DC.
I have already started this recreation so any quick help would be greatly appreciated.
(Edit #2: more info on status)

The new domain is created (with the same name as the previous domain)
DNS is configured with forwarders
My user account (DOMAIN\james) is created
My computer is already joined to the (old) domain so I have to join a workgroup, restart, join the domain again.
When I join the new domain I cannot join "domain.lan" since it gives an error that the AD DC could not be found (DNS could not be found)
If I join the NetBIOS name "domain" it works but I get a long timeout and an error: Changing the Primary Domain DNS name of this computer to "" failed. The name will remain "domain.lan".
The name is then changed from "domain" to "domain.lan" which seems ok
After reboot a "Please Wait..." shows up, before the login and it stays for several minutes before it proceeds to login
I can login with the new domain account but when I try to add the domain account as a local admin I cannot choose "Active Directory" as locaion, only local accounts can be added - why is that?
Answer: Unfortunately all of the migration tools and API's require the source domain to be online to add sidHistory, so you could add the SID for user1 from the previous domain to the new account.   But I think it is possible to edit sidHistory if you add a Samba4 domain controller to the domain.
http://cosmoskey.blogspot.co.uk/2010/08/online-sidhistory-edit-sid-injection.html
Answer: I assume your domain isn't terribly large.
WHat you really need to get up and running after Domain Services is DHCP. Then DNS. Make sure they're both running. The re-join workstations to the domain.
'Active directory' isn't a location, your domain is. You should be looking for your domain.


How can I detect malicious activity based on patterns of DNS requests?

Question: I want to know whether a client is infected by detecting malicious activity based on patterns of DNS requests.
e.g.Suppose someone hacked google website and injected codes in it and when user clicks on it then there will be multiple DNS queries.
Suppose one pattern of DNS queries like
request 1: www.google.com
request 2: www.intermediate.com
request 3: www.malicious.com
request 4: www.malaciouscontent.com
Here, first request is valid and legitimate but the requests from 2nd to 4th are causing because of the injected codes and that pattern is what i want to detect if such requests comes in future.
Comment: you might find this an interesting read "Monitor DNS Traffic & You Just Might Catch A RAT" - http://www.darkreading.com/attacks-breaches/monitor-dns-traffic-and-you-just-might-catch-a-rat/a/d-id/1269593
Answer: There is no way to reliably detect all malware using DNS analysis only but DNS analysis can help a lot.
While some malware might be detected based on access to known to be bad domains (i.e. domain blacklists) other might be detected because they use uncommon domain names or use a known domain generation algorithm. Deeper analysis can also make domains stand out which have rapidly changing mappings to IP address, i.e. fast flux networks. There is also be malware which stands out because of use of TXT records or similar. But there is also malware which communicates using social media sites and thus does not stand out in most networks. And of course there is malware which uses fixed IP addresses for communication and thus does not cause any DNS traffic at all.
In short: there is no reliable way to detect malware using DNS analysis only. But DNS analysis can help a lot. The easiest ways are probably DNS blacklists provided by various vendors or the use of specific DNS servers like OpenDNS which already block lots of suspicious DNS activity. Apart from that the better you know your network the more unusual activities stand out. These might indicate malware activity, but there might also be other reasons for unusual activity.
Comment: Eh...I disagree strongly. DNS logs are a painfully underrated method of detecting malware, especially if you're using RPZ or explicitly whitelisting domains (blacklists are the wrong approach). Most of the malware we see reaches out to bizarre domains and TLDs we have no business dealing with and the rest is denied based on IP blocks. Knowing what domains are being called not only tells us what malicious activity is being attempted but also handily enumerates *who* our adversaries are before we even begin the reverse engineering process.
Comment: @Johnny: I'm not sure which part of my answer you disagree with. I'm not saying that DNS analysis does not help but actually I have lots of examples of where it can help. I'm trying to say instead that using exclusively DNS analysis is not sufficient to detect all malware. I hope I made this more clear in the edited answer.
Comment: It is more clear now, yes. Initially I got the impression you were dismissing it as a useful tool despite the examples.


Logging for ConnectedAppPlugin class

Question: I have a Connected App Handler Class (that extends the Auth.ConnectedAppPlugin) for one Connected App I am having. Use case is this class is used to set some additional attributes for which the standard customAttributes() method is overridden from the parent class. When a user logs in to Community, this class is invoked and sets the parameters.
However, much as I try to log some debug statements inside this class, I fail to see any logs generated for this class. I tried to turn logs on for the Portal User as well as the Trace settings on the Class itself, none worked. Can anyone point me in the right direction, what am I missing here? Which user do I log, to get the logs? Many thanks.
Answer: I found my answer, in the Connected App Configuration, in the "Custom Connected App Handler" section, right below the "Apex Plugin Class", there is a field "Run As". It is the user which is set in this field, that is to be logged.

Logging for ConnectedAppPlugin class


Elimination of hydroxyl group while deprotecting acetal

Question: Regarding this reaction, other than de-protecting the acetal, will we have an elimination reaction for the alcohol or no?
Comment: Base is of no relevance here. It depends entirely on how strong the acid conditions are. It is easy to select conditions that will deprotect without elimination though you could easily form the hemi-acetal of the ketone.
Comment: Welcome to Chemistry.SE! We have a site policy for [homework](http://meta.chemistry.stackexchange.com/q/141/7448) questions. Please edit your question to include your attempt at the problem, where you got stuck, and let us know where you're finding difficulty so we may best help you.
Comment: You can't eliminate hydroxyl groups with base
Answer: As I said in the comments, it entirely depends on the conditions. It is easy to select mild conditions to cleave the dioxolane. Elimination would require very strong forcing conditions (concentrated acid and heating). The first site of protonation is the carbonyl, so you would form the hemi-acetal of the product long before elimination or substitution occured at the primary alcohol. If you were foolish enough to heat this with cH2SO4 then you could get elimination of the primary alcohol and generate quite a mess.


Connection Problems with multiple access points with single SSID

Question: I have an android tablet from insignia running jelly bean. The campus center at my school has multiple routers in it with the same ssid. However when I attempt to connect to the internet the connection jumps around to all the routers and never establishes a solid connection. Is there a way I can fix this?
Answer: Edit: oh damnit, just re-read your post, and realised you're talking about Android.  No clue on that front I'm afraid!
I just discovered a partial solution to this.
The utility WirelessMon (http://www.passmark.com/products/wirelessmonitor.htm) allows you to override Windows wifi selection, and explicitly connect to an AP by MAC address instead of SSID.  It's quite useful for checking general wifi quality too.
The downsides of using WirelessMon are, it's only a 30-day trial, and it also tends to screw up the connection itself by constantly scanning in the background. The best solution I've found is to set its sampling rate to the maximum of 60 seconds, which helps enormously compared to the default of 3.
I'd really like to find a free app that does the same thing.  Even better if all it does is the MAC thing, and no background scanning.


What to do with a collection of theoretical math books?

Question: My father had a Ph.D. in mathematics. He was a consummate mathematician and enjoyed reading about all topics related to math. He passed away a couple of years ago. I have yet to find a suitable place to donate the many theoretical math books he had in his library. I want these books to get a second life by being read by those who would understand and value their content. (I could provide a list of titles if that would be helpful.) Any guidance from this forum would be greatly appreciated. Thank you.
Comment: Which country are you located in? This may change the nature of the answer. I can assure you many mathematicians value such books very highly!
Comment: I'd be willing to take them!
Comment: The American Institute of Mathematics is building up a library.  Contact Brian Conrey at firstname.lastname@example.com
Comment: see also https://mathoverflow.net/q/404161/11260 and https://mathoverflow.net/q/9793/11260
Comment: When Alf van der Poorten passed away, leaving a collection of about 1,200 books, we found it harder than expected to give them away. The library at Macquarie University (where Alf worked) at first only wanted three of the books – they said the rest were already available at other Australian universities. We eventually convinced them to take about half the books, the ones they didn't already have. The Math Department at Macquarie had no space for the rest. But MATRIX https://www.matrix-inst.org.au/about-us/ was happy to take them. (continued)
Comment: (continued) If your country has some math institute just starting up, as MATRIX was here, they might be eager for the donation.
Comment: Does this answer your question? [What to do with antique math books?](https://mathoverflow.net/questions/9793/what-to-do-with-antique-math-books)
Comment: It is always possible (although a long-shot) there are (monetarily) valuable books, even if theoretical, in the collection. e.g. a first edition of Theory of Games and Economic Behavior with dust jacket is worth a pretty penny.
Answer: Most large universities have a library that could take them, and where students could find them and "give them a second life." If the library doesn't want them, many math departments have a common room with a miniature library inside. You could ask the chair of the department (or the department's administrative assistant) if that common room has space for more books. Again, this way they get to a place where mathematicians and math students can find them.
As already pointed out by Stopple in the comments, AIM is another option, but then you might incur shipping costs. Another option, mentioned in the thread What to do with antique math books? linked by Carlo Beenakker, is the Internet Archive which might want them, to scan them to put them online. But, again, they might not cover shipping. For details, see: How do I make a physical donation to the Internet Archive?.
I think focusing on your nearest large university is the way to go.
Comment: Even if there is not an official departmental library, many math departments have tables where e.g. faculty who are retiring leave books they don't want to be claimed by grad students and other faculty.
Comment: I am located in Phoenix, Arizona, USA. I will try AIM. Then ASU (who I do not think takes books). Then NMSU. Then a few of the other institutional options before I send to mathworker21 who has kindly offered to take the books as well. Thank you all so much for your suggestions. I will post again when I find the books their new home.
Comment: @SimoneBerg Did you finally manage to find these books a good new home?
Comment: @Hvjurthuk Not yet. Too many other distractions that have taken priority. (It will take me hours and hours to type up a list of all the books and I just don't have the time right now.) Thank you.
Answer: The London Mathematical Society has a programme "Mentoring African Research in Mathematics".  The main people involved are listed at https://www.lms.ac.uk/MARMBoard.  In particular, the chair is Frank Neumann (https://le.ac.uk/people/frank-neumann).  I suspect that they know of many places that would welcome books but have few resources to buy them.  Of course, someone would have to pay for shipping, which might or might not be an issue.
Answer: In Brazil, people are used to do as most people here suggested: find a public or university library that could receive your dad's collection. It would be interesting observing a trade-off, since you may want the collection to be as well care as possible, while having the maximum impact on the community it will serve. A public university library would be the primary option here, specially those that are more inclusive and/or suffer from a lack of resources to assemble their collection.
Answer: I too live in the greater Phoenix area and as a member of the Humanist Society of Greater Phoenix (official building is in Mesa), I'm sure they'd happily take them off your hands. There is a library at the center as well as the option to donate to the "Little Free Library" they host.


What preprocessing steps to be followed before image comparison?

Question: 1
down vote
favorite
For example I am trying to find the similarity between two images using skimage - SSIM. The code block will be as follows
from skimage.measure import compare_ssim as ssim
from skimage import io
from skimage.transform import resize

a = io.imread("http://ecx.images-amazon.com/images/I/51PV4Dd8wAL._AC_UL246_SR190,246_.jpg",as_grey=False,dtype="float64")
b = io.imread("http://ecx.images-amazon.com/images/I/914ZHE6JolL._UY500_.jpg",as_grey=False,dtype="float64")

a = resize(a,b.shape)
ssim(a, b,multichannel=True)

I got the similarity score as follows
0.21009350738786017

Although both the images are same where one images in slightly oriented , I am getting very really low scores for this comparisons. Am I missing any preprocessing steps here before I compute compare images. If so what are the things I should consider before comparing images.
Thanks In Advance !!
Answer: There is not any fault! This is one of pitfalls of SSIM. It is very sensitive to the geometrical degradations such as orientation!


Different axioms of probability

Question: I wonder if there are some other attitudes to the probability than those related to Kolmogorov? Did somebody try to do those things differently?
Comment: Yes. One variation on Kolmogorov's axioms is to have finite additivity $P(\cup_i A_i) = \sum_i P(A_i)$ for a finite collection of mutually disjoint events $A_i,$ but not to include an axiom that guarantees this for a countably infinite sequence of disj sets. Many familiar practical thms can still be proved, but some measure-theoretic complications are avoided. // Book "How to Gamble If You Must" by Dubins and Savage explores this alternate formulation (more seriously and deeply than the flippant title might lead you to suspect). 1960s. Google and look beyond commercial stuff on first few pgs.
Comment: Along similar lines, I think, is Bruno de Finetti, *Theory of Probability: A Critical Introductory Treatment*, 2 vols., 1970, English translation Wiley 1974.
Answer: There are many variations to the axioms of  probability. The main distinctions are

Finite additivity instead of countable additivity. This was favored by early statisticians like Bernoulli.
Bayesian axioms of probability defined using conditional probabilities. Kolmogorov's axioms are a special case of this.

Different axioms of probability


Floating eye win / loss condition [spoilers]

Question: If a hero is broken out of mind control, they cannot be controlled again. Heroes that are controlled do not attack other heroes, only board the spaceship. Does this mean that if a single hero breaks mind control, the heroes automatically win, with the freed hero just bashing the spaceship?
Answer: No, a hero breaking free of mind control does not itself make the game unwinnable for the traitor.
The Traitor's win condition for this haunt is exactly as follows:

You Win When ...
... all of the heroes are either dead or on the spaceship.

Note that if either of these happens to a hero, they are out of the game. Effectively, this means that the traitor wins when all heroes are unable to act. The "can only mind control a hero once" limitation simply means that any hero that breaks free of mind control must be killed for the traitor to win.
Comment: *"... the traitor has no way to kill heroes"* - ***what?!*** This is not correct at all. The Alien can make Might attacks on Heroes.
Comment: But the traitor has no way to kill heroes, so the only way for them to die would be to enter a room and have it kill them.  IMHO there should be a time limit on destroying the space ship.
Comment: Oh, that is what I was missing.


Why in Rogue One do the AT-ATs blow up when attacked and not in the Empire Strikes Back?

Question: In Rogue One Blue Squadron got through before the shield closed and managed to blow up AT-ATs but in The Empire Strikes Back they have to use cables to bring them down. Why?
Comment: Do you want an in-universe answer? Because the out-of-universe answer is: better special effects budget.
Comment: They were transporting Kyber crystals, which are dangerous when exposed to energy blasts, as we know from the unfinished CW episodes on StarWars.com, so maybe that's why thet exploded.
Comment: Not all of them blew up. Only two out of three I remember.
Answer: They were not AT-ATs but AT-ACTs (all terrain armoured cargo transports).
Wookieepedia link
They are larger than AT-ATs but have no armour covering their centre which is open and used to transport cargo.
Have yet to see a vehicle cross section on this one but AT-ATs used heavy blast resistant armour plating making blasters all but useless against them (in old canon the snow speeder blasters were more powerful than what was found on x-wings) since these were cargo transports it could just be normal armour plating.
Also in old legends canon the ESB ATAT was still under construction and testing during this time with the battle of hoth being its first official battlefield test.
Comment: @Bosc

"in old canon the snow speeder blasters were more powerful than what was found on x-wings"

Are you sure?  Someone here ( http://scifi.stackexchange.com/questions/29242/why-didnt-the-rebels-on-hoth-use-x-wings-to-fight-at-ats ) quoted the novel _Isard's Revenge_ to indicate that the X-Wings stood a greater chance against the AT-ATs due to more powerful weaponry (the user stated that they used blasters on the AT-ATs).
Comment: @Spar10Leonidas Leonidas From a certain point of view :D While EU canon had everything including commando ewoks destroying ATAT's, Game canon had snowspeeder blasters more powerfull these same blasters were outfitted on larger cargo freighters as well.
Comment: It may have been that the events of Rogue 1 led the Empire to strengthen the armor of the ESB ATAT deciding they did not want them vulnerable to attack by fast moving attack vehicles.
Comment: Where is th einfo from about the AT-ACTs?
Comment: @Thomas added link to the wookie entry about the at-act to the answer, its very barebones as it seems not alot of info has been releaased yet about it.
Answer: Different Equipment
The T-47 airspeeder was very much a jury-rigged combat vehicle. It was designed by the Incom corporation as an industrial cargo-handler, and was later modified by the Alliance with weaponry. If we were to find a modern-day analogy, it would be something like a so-called "Technical" - a pick-up truck with a gun mounted in the back. A vehicle like this is fine for patrolling and anti-infantry work, effective against light armour like an AT-ST, but it was totally outclassed by a heavily armoured combat vehicle like the AT-AT.
The T-65 X-Wing is a totally different beast. It was a purpose-built starfighter, designed to attack armoured targets and blow the living, ah...daylights...out of them, and had sufficient shielding to survive attack runs on defended targets. The closest comparison would be something like the F/A-18 Hornet, which is designed to fight its way to a target, hit the target, and fight its way back out again.
In fact, the X-Wing was originally being designed for the Empire, as a more powerful complement to its fragile TIE fighters. At the end of development, however, the entire Incom corporation defected to the Rebel Alliance, taking all the designs and prototypes for the X-Wing with them.
Comment: This is a great post, but you missed a critical and canonical important point. "We're having some trouble adapting them to the cold." There's no evidence that the X-Wings were modified in a similar way, and both vehicles being manufactured by Incom probably shared similarity in design and parts. The X-Wings were probably unable to spend extended amounts of time operating in support of ground operations on Hoth.
Comment: Absolutely, I agree that's why the X-wings weren't used, but I'm not sure it belongs to this question, since the question was specifically about why the different vehicles had different capabilities.
Comment: Not saying you're wrong, but thats an odd backstory for the T-47 with its very large laser cannons that seem very well designed and integrated into the ship.  Its a much more seamless integration than bolting a gun turret to a pick-up.
Answer: The X-Wings and other fighter craft taking part in the battle on Scarif in Rogue One have more powerful weapons available to them than the blasters on the snowspeeders used during the Battle of Hoth.
Even if the X-Wing blasters aren't enough on their own, they've got their missiles/torpedoes.
In the Battle of Hoth a walker is shown being blown up by blaster fire after having been weakened by other damage first.
Comment: This is what I'd assumed as well, that the X-Wings simply had better gear than the snow speeders.
Comment: Wasn't that shots into the top/roof armour after it tipped forwards? (It's been a while)  Anyone who knows about armoured vehicles will know that the roof armour is typically a lot weaker - all that weight needs to be supported, and it, and the supporting structures take away from the weight of armour that can be carried where it's _most_ needed, e.g. on the front of the vehicle.
Answer: Essentialy, both crews used the most suitable weaponry they had available.
In the ESB, movie portraits mainly the T-47 airspeeders, armed only with double laser cannons. On the other hand, they did have the harpoon gun, which they brilliantly used against the walkers.
On the other hand, X-Wings were one of the best starfighters in Alliance arsenal, very verstaile, and equipped with 4 cannons, as well as proton torpedoes launchers. Most of the X-Wings also used astrodroids, who help a great deal with piloting and aiming. Thus, better aim and better weaponry = more destruction. (And they didn't have the harpoon gun, so they had to bring the walkers down with sheer power.)


Initial value problem for a system of ODEs with two parameters

Question: Consider the following initial value problem for the autonomous system of ODEs
\begin{equation}%%\label{eqn: }
\begin{cases}
%\vspace{3mm}
x'(t)=y(t),\; t>0,\\
%\vspace{3mm}
y'(t)=-\frac{\displaystyle x(t)}{\displaystyle\sqrt{1+c_1+x^2(t)}}\,y^2(t)-\big(1-\sqrt{1+c_1+x^2(t)}\big)\,x(t),\; t>0,\\
x(0)=0,\; y(0)=k,
\end{cases}
\end{equation}
where $c_1$, $k$ are parameters. I'd like to find $c_1>-1$ and $k\in\mathbb{R}$ such that a nontrivial solution $(x(t),y(t))\not\equiv (0,0)$, $t>0$ exists and satisfies the additional condition $x(1)=0$. My idea essentially is "try and error", i.e. choose some $c_1$ and $k$ and use numerics to find $(x(t),y(t))$. However, I failed to find such $c_1$ and $k$ and this seems not a systematic approach and is not so efficient. Such problem belongs to the so-called inverse problems, controllability problems, or other kinds of problems? Or I may refer to some references or papers related to this kind of problems? Thanks!
Comment: If you can post the explicit expressions for $f$ and $g$, it might be helpful. Also, it might help to solve both forwards from $t=0$ and backwards from $t=1$, but that's essentially a more elaborate version of trial and error.
Comment: Thanks. I've posted the explicit expression. Any idea to solve this problem is welcome.
Answer: The best thing to do is to analyse the system using a dynamical systems perspective. That is, to (1) find all equilibria of the system, and (2) to classify the behaviour of these equilibria.
As you easily infer from the ODEs, the equilibria of the system are the solutions of the equations
\begin{align}
 y &= 0,\\
 x\left(1 - \sqrt{1+c_1+x^2}\right) &= 0.
\end{align}
the last equation is satisfied if either $x=0$ or
\begin{equation}
 1+c_1 + x^2 = 1 \;\Rightarrow x^2 = -c_1.
\end{equation}
So, for $c_1>0$, only the trivial equilibrium $(x,y)=(0,0)$ exists, whereas for $-1<c_1<0$, three equilibria exist, and the two nontrivial equilibria are found at $(x,y) = (\pm \sqrt{-c_1},0)$.
If we linearise the system around the trivial equilibrium, we see that the eigenvalues of the linearisation are given by $\lambda = \pm \sqrt{\sqrt{1+c_1}-1}$. Therefore, for $c_1>0$, the trivial equilibrium is a saddle; for $-1<c_1<0$, the trivial equilibrium is a centre. This is relevant for the following reason: you're looking for an orbit which starts somewhere on the $y$-axis, and which crosses the $y$-axis again at some specified later time ($t=1$). From the phase plane for $c_1>0$, it is immediately clear that no such orbit exists.

However, for $-1<c_1<0$, any orbit found in between the two nontrivial equilibria is closed, i.e. periodic, and therefore crosses the $y$-axis infinitely many times.

This will definitely give you more insight in the possible values of $c_1$ and $k$.
Note 1: The phase plane figures are made with the java-applet PPlane.
Note 2: You can do a lot more analysis on this system, to get more explicit expressions, etc. However, as you're interested in numerics, I'll leave that for now.
Comment: Thanks very much for the calculation using PPlane. I will read it in more details. So from the experiment using PPlane, such $c_1$ (as $-1<c_1<0$) and $k$ could exist? If so, I'd like to use mathematical analysis to show that such $c_1$ and $k$ exist for this problem. Then I will try to find numerical value of $c_1$ and $k$.
Comment: Such $c_1$ and $k$ could definitely exist. I suggest you give the analysis a go, and maybe post another question if you get stuck.
Comment: Thanks for introducing PPlane. Now I'm enjoying it and making the same plots as you did. I choose $k=0.005$ and $c_1=-0.7$, and obtain a solution $x(t)\not\equiv0$ satisfying $x(0)=0$ and at $t\approx5$, $x=0$ As the ODE system is autonomous, perhaps by suitably adjusting $c_1$ and $k$, we can find a solution $x(t)\not\equiv0$ satisfying $x(0)=x(1)=0$, right?
Comment: About the proof of the existence of $c_1$ and $k$, any idea?
Comment: I did some experiments on different choices of $c_1$ and $k$. However, it seems that I cannot find $c_1$ and $k$ such that $x(t^{\ast})=0$ for $t^{\ast}<t_1$, where $t_1\approx 3$. Does $t^{\ast}$ has a lower bound less than 3 (approximately)? This phenomenon seems interesting!
Answer: $$\begin{cases}
%\vspace{3mm}
\frac{dx}{dt}=y(t),\; t>0,\\
%\vspace{3mm}
\frac{dy}{dt}=-\frac{\displaystyle x(t)}{\displaystyle\sqrt{1+c_1+x^2(t)}}\,y^2(t)-\big(1-\sqrt{1+c_1+x^2(t)}\big)\,x(t),\; t>0,\\
x(0)=0,\; y(0)=k,
\end{cases}$$
$$y\frac{dy}{dx}=-\frac{x}{\displaystyle\sqrt{1+c_1+x^2}}\,y^2-\big(1-\sqrt{1+c_1+x^2}\big)\,x,\;$$
With $\:Y=y^2\:$ :
$$\frac{dY}{dx}=-2\frac{x}{\sqrt{1+c_1+x^2}}\,Y-2\big(1-\sqrt{1+c_1+x^2}\big)\,x$$
With $\:X=x^2\:$ :
$$\frac{dY}{dX}=-\frac{1}{\displaystyle\sqrt{1+c_1+X}}\,Y-\big(1-\sqrt{1+c_1+X}\big)\;$$
This linear ODE is easy to solve. The solution is :
$$Y(X)=2+c_1+X-2\sqrt{1+c_1+X}+Ce^{-2\sqrt{1+c_1+X}}$$
The equation of the trajectory is :
$$y(x)=\pm\sqrt{2+c_1+x^2-2\sqrt{1+c_1+x^2}+Ce^{-2\sqrt{1+c_1+x^2}}}$$
In order to know the time at each position on the trajectory, one have to integrate :
$\frac{dx}{dt}=y(x)\:$ then $\:dt=\frac{dx}{dy(x)}$
$$t=\int \frac{dx}{ \sqrt{2+c_1+x^2-2\sqrt{1+c_1+x^2}+Ce^{-2\sqrt{1+c_1+x^2}}} }$$
Comment: LCH: This is the type of analysis I was talking about. @JJaquelin: I believe there is a mistake in the solution of the ODE. The method is of course entirely correct.
Comment: You are right, there was a mistake in the solving of the linear ODE. it's corrected. Hoping that all is correct now.


Object instance on single point using vertex group. Blender 3.2.2

Question: I'm a complete noob with blender and just started learning geo nodes. I'm following this tutorial https://www.youtube.com/watch?v=GHGokQoqVb8&t=421s and I know it's for an old version of Blender but its driving me mad that I can't get the simplest thing to work. The guy creates a vertex group using the plane and then uses the single point in the middle to instance a cube but the nodes he uses are no longer the same and I managed to get it only this close (definitely learned a lot while searching how to do it though) I would really appreciate it if you guys help me.
The tutorial:

My attempt
Comment: Thanks so much for the help guys! And also thank you for explaining it so clearly! I've definitely learned a couple of new things from your answers alone!
Comment: You are welcome!
Answer: In Blender 3.2 you have the possibility to directly access individual attributes of your geometry.
A vertex group is such an attribute.
Normally a vertex group is nothing more than a float value between $0$ and $1$, which can also be directly converted to an integer or boolean value and used as a selection.
And this is exactly how you can solve the puzzle with version 3.2:

Here I use the node Separate Geometry, which gets the vertex group as selection in the input, and outputs two separate geometries in the output, on which I then instantiate the objects.

But there is another solution:

Here I first put the objects to be instantiated into a collection.
With the node Collection Info these are fetched and made available as instances by activating Separate Children in alphabetical order.
If I then put the vertex group into the input Instance Index of the node Instance on Points and additionally select the option Pick Instance, the same result is achieved as before.
Since the vertex group contains a value from $0$ to $1$, either one or the other object is selected.
(Blender 3.2)

PS: To get an overview of the nodes in different Blender versions, I recommend this post:Can't find the node! Which node is available in which Blender version?
Answer: Quellenform has answered your question, so this post isn't meant to be accepted, it's just a side-note to point out that if it's the pattern you're after, it can be made with old-style modification of any quad surface.. e.g. from a plane:

Subdivide (Simple)
Bevel (Vertices, with material offset)
Edge Split and Solidify

Displace (Normals, to separate tiles)
Bevel (Edges)

... Which might make for a flexible workflow, in some circumstances.


How to sort the content of text file .txt by files size

Question: the file has been generated by
ls -Raltr -block-size=M /* > /home/root/all_files.txt

I have tried several commands with grep to no avail.
Comment: Parsing `ls`, even indirectly, is prone to failing in edge cases (groups with spaces in their name, filenames that have newlines in their name, etc).
Answer: The easiest way is to use -S with ls, to sort directory contents by size.  Files are still grouped by directory, which might not be what you want:
ls -RaltrS --block-size=M /*

This approach might not be an option here; perhaps all_files.txt is an old file or was generated on a different computer.  It's still possible to sort the filenames by file size.  For a typical file, a line of output produced by ls -Raltr --block-size=M (note that --block-size starts with two hyphens instead of one) looks like this:
-rw-rw-r-- 1 owner group 1M Apr 16 05:37 file.txt

Use sort with -h (for human-readable numbers such as 1M), and with -k 5 to specify that the file sizes are in the fifth column (delimited by blank space) of text:
sort -k 5 -h /home/root/all_files.txt

Sorting the ouput of ls -Raltr --block-size=M /* that is stored in /home/root/all_files.txt can be messy because of the extra lines that do not list file sizes, so use grep first to get only the lines you want:
grep '^-' /home/root/all_files.txt | sort -k 5 -h

Here, grep '^-' discards lines that do not start with a hyphen (eg, lines that start with d for directory or l for link).
This anwswer works with GNU tools on Xubuntu 16.04.  It has not been tested on MacOS or BSD systems.
Comment: Using `ls`'s sorting option is the right way to go here.
Answer: To sort all regular files in or under the current directory by size, the zsh shell provides the handy ** globbing pattern that matches across / in pathnames (i.e. "recursively down into subdirectories).  It also allows for qualifying a pattern so that you e.g. get only a match of regular files, and that the results are sorted according to the size of these files.
In the zsh shell, this pattern would look like
**/*(.OL)

This would return all regular files (.) ordered in reverse (O) size order (L).
To get the listing of just the files, use
printf '%s\n' **/*(.OL)

To get ls "long listing" output, use
ls -fl **/*(.OL)

(the -f option prevents ls from doing its own sorting of the files).
If zsh is not your ordinary shell, you can still use these commands, assuming zsh is installed on your system:
zsh -c 'ls -fl **/*(.OL)'

You could obviously also add --block-size=M to that if you're using GNU ls.
If you are interested in just the ten largest files, use the pattern
**/*(.OL[1,10])

instead.
Comment: I'm impressed with `zsh`'s globbing features.  Too bad I handle a fleet of servers that includes a lot of legacy systems, so I need to stick to lowest common denominator.


How sensitive are heavily traded options (SPY, AAPL) to brief price changes?

Question: For example if SPY reached a day high of +2% but only for minutes, would call prices rise accordingly such that one could profit from the STC sale of an option of the same strike price?
Answer: Regarding sensitivity, securities with whose options have  high Open Interest and activity are very sensitive to price change in the underlying. If you follow some quotes in real time, you'll see the moment to moment price change in both.
It's important to note that each option has its own delta so the responsiveness of option price is tied to the size of the delta.  An OTM call with a delta of 20 is going to move 20 cents for a dollar move in the underlying.  If you're dealing with an illiquid option with a wide spread, sometimes you might not see any price change in the option if the underlying moves 10 or 20, even 30 cents.
As for the second question about STC after a 2% rise in the SPY, it's not clear what your position is or what you are attempting to do.


English for the French phrase "des angles"

Question: A French novel has the sentence "Les hommes désespérés vivent dans des angles." It's in the context of "desperate" city dwellers living "dans des angles". I can find no translation. It may be referring to something like dark hidden corners of the city, as in "dark alleys"? Is it related to "angle mort" — "blind spot"? Thanks for any help you can provide.
Comment: When quoting from a book you are expected to give references (book title, author, and anything that might help people to help you).
Answer: The context is not about desperate "city dwellers". The sentence is in the very first paragraph of Pascal Quignard's Terrasse à Rome.

Les hommes désespérés vivent dans des angles. Tous les hommes amoureux vivent dans des angles. Tous les lecteurs des livres vivent dans des angles. Les hommes désespérés vivent accrochés dans l'espace à la manière des figures qui sont peintes sur les murs, ne respirant pas, sans parler, n'écoutant personne.

The word just has the usual meaning of "angle", i.e. a geometric figure formed by two line segments that have a common endpoint. This angle constitutes a small place where one can hide if they want to isolate from the world and not be seen.
You can take the word at face value and understand that Meaume hid in dark corners since he was disfigured by acid, desperate after being rejected by the one he was madly in love with, and he did not want to meet anyone, or even be seen. When Meaume says Tous les hommes he is generalising from his own experience.  The dark corners are not specifically in cities, they can be anywhere; the present dark corner where Meaume is speaking from is on a cliff above Ravello, there were others.
This passage has been widely commented and you will find numerous explanations online. An analysis of this passage and  the role of angles as places to hide can be found in « Le Roman à images : description et fragmentation chez Claude Simon, Renaud Camus et Pascal Quignard ». (Chiara Falangola,Thèse soutenue en juin 2013, University of British Columbia, online pp. 190 ff).

English for the French phrase “des angles”


Error while executing gem...Permission Denied

Question: I am attempting to install taps from my Heroku app folder. When I type "gem install taps," I get the following error:

ERROR:  While executing gem ... (Errno::EACCES)
      Permission denied - /Users/jacob/.rvm/gems/ruby-1.9.3-p194/gems/taps-0.3.24/bin/taps

I attempted to remove the taps-0.3.24 folder using rm -r and got this question: override rwxr-xr-x  root/staff for /Users/jacob/.rvm/gems/ruby-1.9.3-p194/gems/taps-0.3.24//bin/schema?
Upon typing yes, it tells me permission denied. Here is the whole exchange:

Jacob-MacBook-Pro:furious-ocean-6122012 jacob$ rm -r /Users/jacob/.rvm/gems/ruby-1.9.3-p194/gems/taps-0.3.24/
  override rwxr-xr-x  root/staff for /Users/jacob/.rvm/gems/ruby-1.9.3-p194/gems/taps-0.3.24//bin/schema? yes
  rm: /Users/jacob/.rvm/gems/ruby-1.9.3-p194/gems/taps-0.3.24//bin/schema: Permission denied
  override rw-r--r--  root/staff for /Users/jacob/.rvm/gems/ruby-1.9.3-p194/gems/taps-0.3.24//bin/schema.cmd?

Any thoughts on how to resolve this issue would be appreciated. Thanks!
Answer: I just ran into this when trying to get the Heroku Toolbelt running. I was able to remove the old version with sudo rm -rf /path/to/gems/taps-x.x.x and then re-install (without sudo).
Answer: You should add "sudo" before "gem...."


Automatic Login with OpenID

Question: Maybe this is superuser, but is there a firefox plugin of any sort that will allow it so when I go to any of the trilogy sites it will just auto log me in?  So I don't have enter my myopenid URL, or password, or anything like that.
Comment: You aren't throwing away your cookies are you?
Comment: Do you have cookies or something turned off in your browser? I don't know how it's cached, but I never have to login again to SO and friends unless I mess with the browser.
Answer: You have to log into OpenID?
Perhaps you should try using MyOpenID, I cannot even remember the last time I had to log in on any of the sites on any of my machines.
Edit:
Also check to make sure you are not clearing cookies when you exit your browser. Stop that sillyness.
Comment: @Kyle - Sounds like you've told your browser to clear cookies when you close it. You might want to turn that off (see http://support.mozilla.com/en-US/kb/Options+window+-+Privacy+panel)
Comment: Solution in Firefox was: Edit :: Preferences :: Privacy :: Clear History When Firefox Closed :: Settings :: Uncheck Active Logins.

Automatic Login with OpenID


Disable Default Word Wrap in Google Spreadsheets

Question: Does anyone know how to make it so that Word Wrap is OFF by default in Google Spreadsheets?
Answer: There is not, at this writing, a global setting that would automatically affect all new spreadsheets that you create.
To turn off word wrap on any sheet, select all the cells of the sheet and select the "Wrap text" option from the toolbar:

Once all cells have word wrap turned off, it will also be true that new rows and columns will have word wrap turned off, because they take their formats from their neighbors.
However, when you cut and paste a range (or drag-move a range), the empty cells left behind revert to the default format. For this reason, I do not cut and paste. Instead I copy and paste, then reselect the original range and backspace or delete to blank values. This leaves the format intact.
Comment: Note that the "word wrap" option is not under any menu - it's only in the toolbar.
Comment: There's only 3 options for this Wrap text button: "Overflow" "Wrap" and "Clip". There's no "Disable" option :(
Comment: @Hlung What would it do?
Answer: As noted above, there is currently no way to change the defaults for this or, apparently, other features like font or font size.
@erel-segal-halevi: Text wrapping is (now) on the Format menu, not just in the menu bar.
Quick key combination to update your entire spreadsheet to Wrap Text:
<code>Ctrl-a Alt-o then w then down-arrow
</code>
Select all; Open Text Wrap Submenu; Select Wrap Text (from overflow - the default)
Comment: Please note that "above" has no context here. Answers can be sorted a number of ways and, even if left at the default sort, the order can change as votes accumulate on answers. Better to provide a link to the answer to which you are referring.


Cannot boot up when Adaptec SCSI card is replaced

Question: Current Fedora 19 installation is on an Adaptec 29320 and I am trying to
temporarily replace it with an Adaptec 29160. The functionality of the cards is
very nearly the same except the replacement is U160. All the other drives, ID's and configurations remain the same. About half way through the boot process everything stops and I get dropped to a dracut prompt. It gives me the UUID's of two devices(disk partitions) it says it can't find. These are the partitions for swap and for the root file system. Using a different SCSI controller seems to create a different UUID that doesn't match what's in the initramfs. It appears that the dracut prompt is giving me the opportunity to create a new initramfs right on the spot that will allow the boot process to continue. But I would need to know what parameters/options etc to give it. I went back into my installation and regenerated the grub.cfg using the variable GRUB_DISABLE_LINUX_UUID=true. The new grub.cfg now has root=/dev/sdc2. But this only gets me a little further in the boot process.
Answer: A RAID controller cannot change the uuids of your partitions. It can, however, change the way in which RAID devices are constructed; that is, what they use as on-disk format, how disks are synced between each other, etc. Even controllers from the same brand are not at all guaranteed to use the same on-disk format.
If you're booting from the RAID, but then things fail after loading the kernel etc, then that would appear to mean that either the new RAID controller used a similar (but not identical) on-disk format, or (far less likely) that loading the driver and initializing the hardware changes the mode in which the controller works, causing it to look at the disks in a different way. Either way, you clearly cannot use the array created with one controller after switching controllers.
It you do want to do so, the only way is to put in the old controller, back up your data, swap controllers, reinstall, restore your data.
Comment: These aren't RAID controllers, they're just plain SCSI HBAs.
Comment: @WouterVerhelst  Actually, both of these cards have a certain amount of RAID capability that is available as an option.  It's something that I have never used and I believe most of the time I have deactivated it by turning it off in the SCSI BIOS settings.  I know it's been turned off on the 29320 since before the Linux installation.  It's been a while since I have used the 29160. When I installed it, I didn't think to go into the SCSI BIOS and check all the settings.
Comment: Maybe double-check that you have switched it off, then?


How to merge all files manually in Git?

Question: I want to merge all files manually with meld or any other diff tool, how can I do this with Git?
When I run git mergetool
it says no files need merging. So I suppose I can do it only if I have conflicts.
Comment: Yes, I would like to merge manually in some cases because in such situations I know that everything goes as I want, not as the app decided
Comment: @TomaszWysocki because there is no way for me to know if a "problem as deemed problematic by the human" has arisen. There is only a way for me to know if a "problem as deemed problematic by git" has arisen. Git merges files automatically and I don't get to checkmark all of git's automatic decision-making results. It can decide to make a specific change that I don't like. I want to approve all changes before they are made.
Comment: I want to merge text files :) I used to mercurial's manual merging and like to see 3 files simultaneously, if something goes wrong I always can edit all of them by myself
Comment: What about merging automatically and fixing problems if happen?
Comment: Please provide us some context of *what* you want to merge and *why* you don't want this done automatically.
Comment: You want to merge different text files of different revisions of the same text file? How are these files related to git?
Comment: Different revisions of the same text files in my case
Comment: So if two branches both modify a given file, even if it's in completely different areas so an automatic merge will work fine, you want to merge it manually instead?
Comment: @TomaszWysocki As far as I know, this is no longer usable scenario, git no longer allows automatic merges when there are conflicts detected.
Answer: There is much simpler way:
git merge --no-commit merge_branch
As man says:

With --no-commit perform the merge but pretend the merge failed and do
  not autocommit, to give the user a chance to inspect and further tweak
  the merge result before
             committing.
Comment: This is still an automatic merge, so this doesn't answer the origin question.
Comment: By adding `--no-ff` the fast forwarding is disabled, which will happen if there are no conflicts.
Comment: Thank you. Is there perhaps a way to use mergetool/meld to review and merge the changes piecewise with a nice threeway interface?
Comment: And of course, use `git mergetool` if there are conflicts.
Answer: I had a scenario where:
git merge --no-commit merge_branch

just caused a Fast Forward.
If this happens you can use:
git merge --no-commit --no-ff merge_branch

and then you'll be able to review your changes
Comment: I get `Automatic merge went well; stopped before committing as requested` upon running that. When I try to run `git mergetool` it says `No files need merging`.
Comment: Is it possible to pull it in the same way? I need to verify ALL conflicts manually if fast-forward is not possible.
Comment: @Maxim no but since `pull` is just the combination of `fetch` and `merge` do first call `git fetch merge_branch` then latter do `merge`
Comment: using both `--no-commit --no-ff` is like having `.gitattributes` file in root dir containing `* -merge`, but with per `merge` choice to use it or not
Comment: Just speculating this method is effectively like copying files from another source (eg a clone from this repository with current branch 'merge_branch' and clean). In this case I would expect only 'git difftool' showing any changes.
Answer: A similar question is How to prevent an automerge using git?
FractalSpace gave an answer which I think useful:
$ git checkout master
$ git difftool -t kdiff3 local-branch HEAD

The idea is using difftools instead of auto-merging tools to manually pick what you need and create new files.
Comment: I've added an answer comparing this answer to the `git merge` answers to help clarify things for anyone else who stumbles into this page.
Comment: When I try to manually merge this way with kdiff3 or meld, it saves changes to a temporary file in `/tmp` and does not change the working dir. But I need to store changes to the working dir.
Comment: the history might get lost here. Also this dies not show up like a merged branch. For git this might just look like a huge commit out of the void.
Answer: For anyone who just needs to micromanage a merge, jump to the Hybrid section below.
For anyone who is wondering about the difference between @True's answer using git difftool and the other answers that use git merge, see Git mergetool vs difftool.
Here are more details:
Difftool
If you have git configured to use a modern diff.tool such as kdiff3, meld, or vimdiff, you'll be able to manually merge using that diff tool, and the command line can be simple:
git difftool other_branch

...this will let you do a two-way manual merge between your current branch and other_branch (described as $LOCAL and $REMOTE in man git-config).
Mergetool
The "correct" way the other answers discuss would be to instead configure git to use e.g. kdiff3 or vimdiff as your merge.tool, and use:
git merge --no-commit --no-ff other_branch
git mergetool

...this command can do an N-way manual merge between $BASE, $LOCAL, and $REMOTE, into $MERGED. See  https://stackoverflow.com/a/2235841/1264797 for one example of how to configure git.  You many not need to configure the mergetool.*.cmd entry at all if you use one of the tools git already knows about.  (Meld can only show three panes, so if you use meld with the default settings, you'll not see $BASE.)
Difftool vs mergetool
Someone might jump in to correct me, but the main differences between the above difftool and mergetool techniques seem to be:

mergetool can do an N-way merge if configured accordingly
mergetool adds other_branch as a parent on the new commit so history works correctly
difftool lets you manually see and select each and every changed line, but you lose the above two benefits of mergetool

Hybrid -- best of both worlds
A method that combines merging and diffing would look something like this:
git merge --no-commit --no-ff other_branch
git mergetool
git difftool HEAD
git commit

...this does the N-way merge to resolve conflicts and make history work right, and then shows you the complete set of diffs so you can review and tweak before you commit.
Comment: When I try to manually merge this way with kdiff3 or meld, it saves changes to a temporary file in `/tmp` and does not change the working dir. But I need to store changes to the working dir.
Comment: @porton You may have to do some more experimentation, but one of the panes should be the working dir file, or should be a file that gets automatically copied into the working dir after you exit.  I don't remember which, and it may be dependent on your git version and tool config.
Answer: I found the other answers unsatisfactory and became frustrated searching for an answer. A solution to this question I finally found here: https://stackoverflow.com/a/11593308/1351182
If you run these commands, you will create a new commit which essentially takes the latest commit of branchToMergeFrom and allows you to apply a patch on top of it, which I think is like an additional commit on top.
git checkout branchToMergeTo
git checkout --patch branchToMergeFrom [file]

You will then be prompted (file-by-file if you didn't specify file) on exactly which 'hunks' you want to merge. In this way it walks you through each part of what would have been the automatic merge process and instead asks for manual arbitration on which bits and pieces you want to accept from the mergefrom branch. Here's an example of what it looked like in my project:
@@ -249,7 +251,8 @@ def draw_everything():

     draw_bg()
     draw_balls(ax)
-    plt.show(block=False)
+    if show:
+        plt.show(block=False)

 def advance(ms, accel_fun, collision_matrix_fun):
     global balls
(3/6) Apply this hunk to index and worktree [y,n,q,a,d,K,j,J,g,/,e,?]?

After typing y and <Enter>, I was presented with the next hunk, (4/6) for that file. This prompt at the bottom lets you simply accept the merge 'hunk' with y, reject it with n, or even go in and edit it manually. Here are the options:
y - apply this hunk to index and worktree
n - do not apply this hunk to index and worktree
q - quit; do not apply this hunk or any of the remaining ones
a - apply this hunk and all later hunks in the file
d - do not apply this hunk or any of the later hunks in the file
g - select a hunk to go to
/ - search for a hunk matching the given regex
j - leave this hunk undecided, see next undecided hunk
J - leave this hunk undecided, see next hunk
K - leave this hunk undecided, see previous hunk
s - split the current hunk into smaller hunks
e - manually edit the current hunk
? - print help

I wanted to go in and manually edit one hunk, as I didn't want to accept or reject the merge exactly as it was posed. So I chose e and was given a file to edit. I was pleased when I noticed there were even instructions at the bottom on how to edit the hunk properly. You can even split hunks into smaller ones with the s option as above.
I would recommend this process if what you want is manual merging where you still leverage the automatic process as much as possible. The difference is that you get to oversee every merge 'hunk' and edit them as you please. I hope this helps future readers.
After this process, you probably want to run git checkout branchToMergeTo && git merge branchToMergeFrom in order to formally merge the history of branchToMergeFrom into branchToMergeTo.
Answer: Note, if you insists of merging manually (perhaps for a certain class of files), you still can define a merge driver.
You have a concrete example in "Git - how to force merge conflict and manual merge on selected file".
That way, your merge driver script can call any merge tool you want.
Answer: I pick strategy ours (it exist also as a pick in TortoiseGit), after doing a manual diff where you have brought-in changes you wanted manually.
From:
https://git-scm.com/docs/merge-strategies

The merge mechanism (git merge and git pull commands) allows the backend 'merge strategies' to be chosen with -s option. Some strategies can also take their own options, which can be passed by giving -X arguments to git merge and/or git pull.
ours
This resolves any number of heads, but the resulting tree of the merge
  is always that of the current branch head, effectively ignoring all
  changes from all other branches. It is meant to be used to supersede
  old development history of side branches. Note that this is different
  from the -Xours option to the 'recursive' merge strategy.

What Bitbucket see later however is a mystery to me, it recognise the commit as merge but fail to actually merge the branch (does not solve a pull-request) - probably Bitbucket guru could help on this issue, I can not even give you any logs/error messages since I do not have that visibility - git/TortoiseGit does not complain at all though.

How to merge all files manually in Git?


mpiexec vs mpirun

Question: As per my little knowledge mpirun and mpiexec both are launcher. Can anybody tell the exact difference between mpiexec and mpirun?
Comment: mpiexec for example seems to accept the notation host:num_processes in the host names file while mpirun seems not accept that (at least not for mvapich2)
Answer: mpiexec is defined in the MPI standard (well, the recent versions at least) and I refer you to those (your favourite search engine will find them for you) for details.
mpirun is a command implemented by many MPI implementations.  It has never, however, been standardised and there have always been, often subtle, differences between implementations.  For details see the documentation of the implementation(s) of your choice.
And yes, they are both used to launch MPI programs, these days mpiexec is generally preferable because it is standardised.
Comment: On the spot answer! Cheers :)!
Answer: I know the question's been answered, but I think the answer isn't the best. I ran into a few issues on the cluster here with mpirun and looked to see if there was a difference between mpirun and mpiexec. This is what I found:

Description
Mpiexec is a replacement program for the script mpirun, which is part
  of the mpich package. It is used to initialize a parallel job from
  within a PBS batch or interactive environment. Mpiexec uses the task
  manager library of PBS to spawn copies of the executable on the nodes
  in a PBS allocation.
Reasons to use mpiexec rather than a script (mpirun) or an external
  daemon (mpd):

Starting tasks with the TM interface is much faster than invoking a separate rsh or ssh once for each process.
Resources used by the spawned processes are accounted correctly with mpiexec, and reported in the PBS logs, because all the processes
  of a parallel job remain under the control of PBS, unlike when using
  startup scripts such as mpirun.
Tasks that exceed their assigned limits of CPU time, wallclock time, memory usage, or disk space are killed cleanly by PBS. It is
  quite hard for processes to escape control of the resource manager
  when using mpiexec.
You can use mpiexec to enforce a security policy. If all jobs are required to startup using mpiexec and the PBS execution environment,
  it is not necessary to enable rsh or ssh access to the compute nodes
  in the cluster.

Ref: https://www.osc.edu/~djohnson/mpiexec/

mpiexec vs mpirun


Prove that Open Sets in $\mathbb{R}$ are The Disjoint Union of Open Intervals Without the Axioms of Choice

Question: There are several proofs I have seen of this, but they all seem to use choice subtely at some point. Is there any way to prove this without choice, or is it possibly unproveable?
Comment: I misread that comment, sorry. I'll remove my comment now.
Comment: As far as I know, none of the proofs I've seen use the axiom of choice. The use of choice must be too subtle for me. Could you please give an example of such a proof and point out where choice is used? Considering that the decomposition is unique, it seems unlikely that choice is involved. Is choice needed to show that a topological space is the disjoint union of its connected components? Or that the connected components of an open set in $\mathbb R$ are open intervals?
Comment: @bof: You can always force the axiom of choice in there. (E.g. start by enumerating the real numbers) :-)
Comment: @bof: The answer given uses the axiom of choice if you just say that a rational exists for each interval, but you can get around that. Choice is used in the proofs a lot in claiming existance, when existance can be shown without choice anyway.
Comment: @Asaf Karagila: I know you didn't use choice. I didn't say that you did in the above comment. I commented on your answer below saying that it made sense. Not sure what the confusion is here.
Answer: The usual proof uses nothing of the axiom of choice.
Given a non-empty open set $U$, define an equivalence relation on $U$ by: $$x\sim y\iff\exists I\text{ an interval}, I\subseteq U, x,y\in I.$$
Now show that each equivalence class is open, simply by definition. Any point inside has an open interval around it contained in the equivalence class.
Therefore $U$ is the disjoint union of open intervals. And we can do more. We can use the fact that the rational numbers are countable to enumerate them, and choose a unique one from each interval, thus proving that the number of intervals is finite or $\aleph_0$ as well.
Comment: @Unit: No, I have not. The rational numbers can be enumerated (they are countable, without using the axiom of choice). Now choose the least rational in the enumeration from each interval.
Comment: At least countable choice appears in the choice of one rational per interval.
Comment: Haven't you used choice to pick a rational from each interval?
Comment: @Tim: Ping for the previous comment.
Comment: Ah, that makes sense.


Some 510k records with 'statement' value stored in the summary searchable field from openFDA do not have summary information from FDA database

Question: I see there is a searchable field called 'summary_or_statement' from openFDA API to indicate the summary or statement result. However, some records with "statement' value for the summary_or_statement don't have summary links from FDA database. Where could we find the related summary documents?
Answer: There may be instances where that value is not filled in - in these cases, you can cross-reference from our upstream data source, which is also publicly available. That data is located here: https://www.fda.gov/medical-devices/device-approvals-denials-and-clearances/510k-clearances
Regards,
Violet Wren
openFDA Tech Lead


Why do people hesitate to upvote questions that they give an answer to?

Question: If somebody answers a question, he must believe that the question is meaningful and contributes to the community. Then why people hesitate to give other people credit for asking questions? I think if you answer a question, it makes sense to upvote the question for sure. Correct me if my logic is flawed...
Comment: It's hard to say, but you can cover both. People need a reminder every once in a while.
Comment: By the way, you can also bring this to our [Chat Room](https://chat.stackexchange.com/rooms/11177/general-network-engineering-recommendations). People often forget to look here in Meta, and others tend to look at the chat.
Comment: I thought that more people will see it here. Not sure which one is more popular among the regular members.
Comment: So, [here is a question](https://networkengineering.stackexchange.com/q/64803/8499) that got far more attention than the question probably deserves on Network Engineering, simply because it hit the Hot Questions List. It got 26 up votes in two days. Questions that are the real focus of NE often get overlooked, and simplistic questions hit the hot list. I once saw someone remark on the quality of our questions that make the hot list, although I suppose it could widen the audience.
Answer: You are correct, in the general case, and this has been brought up before. For example, this answer.
Unfortunately, people often get so focused on giving an answer that the value of and vote for the question can get lost. That sometimes happens to me when I answer, but I generally try to go back and correct the situation. It also helps if you edit the question or get the OP to edit the question to be more clear and include everything necessary in the question. You will also find that there are people who answer, but simply do not have the reputation to vote up, and there are people who do not really understand how it is all supposed to work.
As questions (answers, too) age, they tend to collect more up votes. The ideal situation is when a question makes the Hot List, then the question and answers to it get a lot of attention and votes in a very short span of time. We have had, so far, six Great Answer (answer score of 100 or more) badges awarded, and five of them took years to get that many up votes, but one of them hit the Hot List, and it got the badge in three days. There are only two Great Question (question score of 100 or more) badges, and both of those took a few years to earn the badges.
We also have several badges that can be earned by voting:

Civic Duty Vote 300 or more times.
Critic First down vote.
Electorate Vote on 600 questions and 25% or more of total votes
are on questions.
Sportsmanship Up vote 100 answers on questions where an answer
of yours has a positive score.
Suffrage Use 30 votes in a day.
Supporter First up vote.
Vox Populi Use the maximum 40 votes in a day.

If you look at the all-time votes cast by user, you may notice that the advocate for voting in the answer I linked is not even in the top 10 for votes. It is simply one of those things that tends to lose focus when someone is working on an answer.

SE recently changed the reputation points for up votes on questions to be 10 (previously five) to match the reputation points for up votes on answers.
Comment: Well, I really have not seen competition for reputation, per se, although we see people like that who pass through, mostly on questions that hit the Hot List, and outsiders start giving me-too answers to gather some reputation. I voted far more than even the next closest person, and I still forget, or I wait until the OP has accepted an answer. I will also wait for the OP to fix the question, even though it has an answer. That is because this is an archive, and just because a question has an answer does not mean it is a good question for an archive.
Comment: Thanks for your answer, Ron. Your points make sense. I'm also relatively new here and didn't know how the hotlist works exactly. Thanks for sharing a similar question that's been brought up. I really share Eddie's views on the topic. I have noticed however that new contributors are asking interesting questions, and a few high rating members answer but nobody is upvoting the question. I'd hope to see a more supportive community and to look at the upvoting as encouragement for contribution as this is its main purpose, rather than some sort rating competition.


Geoexplorer Class Diagram

Question: Does anyone know where I could find a class diagram for the different modules of geoexplorer (geoext and gxp)?
Answer: I spoke with a developer on the opengeo suite project and they said that there was not currently an existing diagram.  I did some research and tried to implement js/uml.  Ultimately I've decided that there isn't a great existing, free option to generate javascript uml from source code.
I posted my experiences with js/uml in the question section of the following thread:
https://stackoverflow.com/questions/20664842/jsdoc-uml-diagram
I just ended up sketching my own diagram.
Answer: You could eventually generate a class diagram from the opengeosuite (geexplorer, GeoExt, gxp)?

Geoexplorer Class Diagram


Idiom for feeling after taking risk and someone else being rewarded

Question: Is there an English idiom about describing the feelings of ones who work hard, get risk and finally achieved it but the others are being promoted and get all benefits as if they did it?
Answer: To give one example from history is as follows:
An old or Roman soldier would say that there are two things in a soldier's life : blood and gold. The soldiers supply the blood and the generals get the gold...
Answer: You could say that you've been left (out) in the cold or given the shaft because the others have taken the credit. You might even think of yourself as an unsung hero, although that term would be more likely applied to you by someone who discovers your contribution after the fact and tries to "correct the record".
Answer: Not an idiom but a proverb:
One beats the bush, and another catches the birds.
Explanation at proverbhunter:

One man does all the hard work, and another reaps the benefits. The reference is to the beater, whose job is to strike the bushes and rouse the birds or other game so that the sportsman with a gun can take a shot at them.


Blockchain size on hard drive?

Question: What is the current blockchain size in gigabytes and is there a service that regularly reports this statistic?
Answer: The current blockchain size is around 78 GB as of July, 2021.
On Windows platforms, you can check the size of the blockchain by checking the size of C:\ProgramData\bitmonero\lmdb\.
On Linux/UNIX platforms, you can check the size of the blockchain in the terminal by executing du -sh ~/.bitmonero/lmdb/.
The Wolfram Warptangent v0.10.0 release bundled in some rather significant database optimizations started by the late developer warptangent (continued and finished by hyc), which shrunk the blockchain down to around 7 GB from 17 GB back in summer 2016.
The Monero blockchain grew fairly quickly in 2017 due to rapid adoption. An optimization known as "Bulletproofs" which significantly reduced the size of all subsequent transactions (~80% reduction) was activated on October 18th, 2018 with the v8 hard fork.
To check the current size of the blockchain (as well as look up historic growth of the blockchain), see https://moneroblocks.info/stats/blockchain-growth
Answer: The blockchain database size is currently 21 GB.
Historical evolution is tracked at http://moneroblocks.info/stats/blockchain-growth. This site claims a smaller size, so it might be tracking the "raw" size, rather than the on disk database size (as the database duplicates some data in order to allow faster lookups).
Answer: As of July 21st, 2017
% cd ~
% du -k .bitmonero

3386256 .bitmonero/export
575384  .bitmonero/fake/lmdb
575384  .bitmonero/fake
21587512    .bitmonero/lmdb
25551504    .bitmonero

Comment: so its 21GB... how do you store it? is your main system linux or mac?
Comment: The .bitmonero directory is located in my user account directory.
Answer: Monthly Blockchain Growth:
https://moneroblocks.info/stats/blockchain-growth
Started April 2014. As of December 2017 it shows as 26 GB.
Answer: There are two resources that report the blockhain size and growth over time.
http://moneroblocks.info/stats/blockchain-growth

https://stoffu.github.io/diff-chart/monero-bc-size.html

The second website loads a lot of information in the browser, so use a desktop browser only and be patient.
Answer: If you have already run it you can simply do a ls on the lmdb directory. However, you probably want to know how much disk space it will take before you run the daemon monerod. So you want to do the equivalent of an ls on the currently running blockchains. As of today you can do the following:
:!x=$(curl -sd '{"jsonrpc":"2.0","id":"0","method":"get_info"}' http://node.moneroworld.com:18089/json_rpc | grep 'database_size' |  sed -r 's/.*: ([0-9]*)\,.*/\1/g'); y=$((x/1024/1024/1024)); echo -e "\tCurrent uncompressed Monero block chain is: "$y"GB"

Current uncompressed Monero block chain is: 140GB

If this ages out and you need a script that pulls from the latest let me know.

Blockchain size on hard drive?


I need 27 x 1 1/4" sew up tires

Question: What is the new teminology for 27" x 1 1/4" sew ups? There are so many new sizes. It seem like 32-630 would be right, but I can't find any that arn't clinchers. I need new sew ups for my 1960 Paramount. And where can I get them?
Comment: I think you've found the term "tubular" already; [this question](https://bicycles.stackexchange.com/q/85903/43557) suggests you're probably looking for a 622 or 630 size.
Answer: Disclaimer that I haven't dealt with this exact issue firsthand, but this is what Sheldon Brown, who is usually reliable and was a working mechanic in the time period when it came up more often, has to say about it:

Standard size tubular tires use a rim that corresponds in diameter to
a 622 mm (700C) clincher rim.
Back in the 1970s, 622 mm clinchers were very rare in the U.S., and
most sporty bikes used either 630 mm (27 inch) clinchers, or standard
(622 mm) tubulars.
The fact that these sizes are so close led to an in-accurate habit of
referring to "27 inch" tubulars. This careless nomenclature still
causes confusion, and people often imagine that there is a different
"27 inch" size in tubulars as there is in clinchers.
This is not true. THERE IS ACTUALLY NO SUCH THING AS A "27 INCH"
TUBULAR.
All full-size tubulars fit all full-size tubular rims.

The answer is thus to get whatever normal 700C tubulars you want. If the ones you have now are wide like a 27x1-1/4" is and if the rims are also wide like that (say 22mm or wider), you should probably be looking at the wider size tubulars.
Alternatively, since clinchers are vastly improved compared to the ones of your bike's era, you could look at doing new rims and tires. Options do exist that would look the part, i.e. high polish box-section eyeletted with tan sidewalls.
Comment: +1 to this. Unless this is a show bike that needs to be period-correct, converting to clinchers is the smart move.
Answer: The word you need is "tubular" tyre, which is a combination of tyre and inner tube.
A tubular tyre ONLY suits a tubular rim, and vise versa.  You'll need tubular glue or tape as well.  Depending how the old one was attached, you may need a hot air heat gun to soften the glue and some kind of soft scraper, I found wooden iceblock sticks to be okay.
As for sizing, well its a mess generally with bike tyres.  Yours is old enough to predate ETRTO standards, but 27" is a diameter and 1 1/4" is a width.  I'd suggest sticking with a 30 or 32mm width because your tube has to fit your rim's curve.
However tubular tyres have a bizarre amount of "stretch" so I suspect a 622mm tubular will also fit a 630mm rim, and probably a 635mm rim with sufficient cussing/patience.   Note I've not done this personally.
Also check the valve type before starting - 95% likely its a Presta aka F/V.
Allow 3 days on-and-off for the whole clean,glue,fit,cure process.  Tubulars are not quick.

I need 27 x 1 1/4" sew up tires


How is running a script like an executable different from running it by a shell explicitly?

Question:
From A Practical Guide to Linux Commands, Editors, and Shell
Programming  By Mark G. Sobell

Although you can use bash to execute a shell script, this technique causes the script to run more slowly than giving yourself
  execute permission and directly invoking the script.

Why is that?
How is running a script like an executable different from running it
by a shell explicitly?
Do both follow the same steps as:

A command on the command line causes the shell to fork a new process,
  creating a duplicate of the shell process (a subshell). The new
  process attempts to exec (execute) the command. Like fork, the exec
  routine is executed by the operating system (a system call). Because
  the command is a shell script, exec fails. When exec fails, the
  command is assumed to be a shell script, and the subshell runs the
  commands in the script. Unlike a login shell, which expects input from
  the command line, the subshell takes its input from a file—namely, the
  shell script.
Answer: Assuming that the script is a Bash script (i.e. it begins with #!/bin/bash), then the author is wrong on this point.  When you run a shell script directly, the kernel sees the #!/bin/bash line at the beginning, then runs that line with the script's filename as a parameter, i.e. /bin/bash myscript.sh.  In other words, the kernel is doing exactly what you would do to pass it to a shell explicitly.
Now, if the script begins with #!/bin/sh instead of #!/bin/bash, then there's another possibility.  Bash can provide /bin/sh, but it doesn't have to.  It also prioritizes features over size or speed.  If a smaller, faster shell is your /bin/sh, then running the script directly will use that faster shell, and the script will run faster than it would under Bash.
This happens in practice with Debian-based distributions (e.g. Debian, Ubuntu, Mint).  They tend to use a shell called dash to provide /bin/sh instead of Bash, in order to make the boot scripts run faster.
To see what your distribution does, ls -l /bin/sh.  It is probably a symbolic link to /bin/bash or /bin/dash, or another shell.
Comment: And the TL;DR of `#!` can be found at http://www.in-ulm.de/~mascheck/various/shebang/ (spoiler: it's complicated)


Light switch with hot pig tail under screw & hot wire in a push-in conncection

Question: One hot wire that has the pigtail & it will go under the screw. The other hot wire needs to go in the Push-In Wire Connection. How far in? What if you can see exposed wire once pushed in the hole? This switch controls one overhead light, nothing else as far as I can tell.
The non hot wire will go under the other screw or in the push-in connection.
Answer: Add the extra hot to the pigtail and then you don't need the push-in connection, which is less reliable than the screw connection.
Answer: Stop using push-in connections altogether. They are unreliable and will cause failures later.
When you need to attach more than 1 wire to a screw, just pigtail with a piece of short wire.  Or you can use the spec-grade switches and receptacles that provide a "screw-and-clamp" method that allow 2 wires under each screw.


Aggressive dog needs insulin

Question: How do I give my rat terrier insulin by myself?  He thinks he's a pitbull. He gets aggressive when you try to do something he doesn't like. Any advice?  I really need help.
Comment: Can you provide more details on exactly how you give insulin (injection, pill, other?), how does he fight you (teeth, claws, struggle to get away, what?)? The reference to pitbull is not helpful when writing answers but knowing the details of your situation and what exactly you need help or advice with is important.
Answer: I strongly suggest setting up a routine that consists of:

A place where you inject the insulin every day. Choose any place your dog feels calm and comfortable (like a blanket) and where you have enough space above and around your dog (not in a crate).
Make your dog calm down. Depending on his temperament, you might have him lay down or at least sit. The emphasis is on calm down. This is not simple obedience training where you test whether your dog understood that "sit" means "put your bum on the ground". Please have a look at this youtube video to understand what I mean.
The actual injection. If you are unsure how and where to inject the insulin, please ask your vet.
A very yummy and special treat your dog only ever gets after the insulin injection. This could be a piece of cheese or hotdog wiener or anything he really likes to eat. He will get this treat every time after the injection, no matter how badly he behaved, and never anytime else.

This is supposed to give your dog a routine he can expect every day. He learns that you follow these steps every day in the same order, which gives him a certainty as to what to expect.
The calming down is supposed to - well, calm him down. He should learn that he cannot avoid the injection by erratic behavior or by fighting back. It also (hopefully) calms you down, which makes the experience much more tolerable for your dog. If you are nervous before an injection or your dog is wriggling around too much, it helps to take the time to take a deep breath. You can also pet your dog for a few minutes if it helps him calm down. It's not important to inject the insulin each day at the same minute, it's more important to make your dog accept the injection.
The special treat is there to connect the stimulus of the insulin injection with a positive outcome. This is classical conditioning and works just like clicker training. A stimulus that doesn't mean anything to the dog - the sound of the clicker or the sight of the insulin injector - is connected to a positive outcome - a very tasty treat. The positive feeling connected with the treat is then connected to the initial stimulus (the insulin injector) as well. That's why it's important to treat your dog after every single injection: the treat is not connected to his good behavior, but to the injection itself. Every time there is an injection, there follows a treat.
Important note: the faster you feed him the treat after the injection, the faster he learns to associate the injection with the treat. Have the treat in arms reach before you inject him - but somewhere where he cannot snatch it from you.
If your dog has the tendency to nip or bite, you might want to use a muzzle the first few days until he associates the injection with something positive. You can feed him the treat with the muzzle still on.

Aggressive dog needs insulin