Correlation test for categorical varibale when expected values are less than 5

Question: I'm trying to do a correlation test between two categorical variables. The independent variable is nominal (Item Type: A, B, C) and dependent is ordinal (High, Medium, Low). When I try to apply the Chi-square test I noticed that some of the expected values are less than 5. Can someone suggest a suitable correlation test/methodology find a correlation between the variables in such a case?
Answer: At the outset, Chi-square test is for testing the significant of association between categorical variables. It is not  correlation. The term correlation can be used when both the variables are having orders (low-high). The expected count is different from the observed count. The observed count is the count that your data has in each cell of the cross tabulation. The expected count is the count calculated based on the ratios of each cell counts by rows and columns. If the number of cells having the expected count less than 5 is less than 20% of the total number of cells, there is no problem. Chi-square test requires at least 80% of the cells to have the expected count more than 5.
One option is to merge the two categories. You can merge the category having the counts less than 5 with the nearest category by row or by column (merging two categories in first variable or in second variable) and perform the Chi-square test.


Unable to open .xls file in Python, xlrd.biffh.XLRDError: Unsupported format, or corrupt file: Expected BOF record; found '<?xml ve'

Question: I am trying to extract data from an excel file and unfortunately the xlrd library documentary is not opening up the file and it is throwing a lot of errors. For reference, I have a .xls file with 10+ pages of data
I've tried to use the xlrd library with no luck, here is my code:
import xlrd

file = "C:\TestAutomation\doc\Smart_CID.xls"

wb = xlrd.open_workbook(file)

print(wb.nsheets)

Here is the Traceback:
Traceback (most recent call last):
  File "C:/TestAutomation/src/XML_parser.py", line 7, in <module>
    wb = xlrd.open_workbook(file)
  File "C:\Python27\lib\site-packages\xlrd\__init__.py", line 157, in open_workbook
    ragged_rows=ragged_rows,
  File "C:\Python27\lib\site-packages\xlrd\book.py", line 92, in open_workbook_xls
    biff_version = bk.getbof(XL_WORKBOOK_GLOBALS)
  File "C:\Python27\lib\site-packages\xlrd\book.py", line 1278, in getbof
    bof_error('Expected BOF record; found %r' % self.mem[savpos:savpos+8])
  File "C:\Python27\lib\site-packages\xlrd\book.py", line 1272, in bof_error
    raise XLRDError('Unsupported format, or corrupt file: ' + msg)
xlrd.biffh.XLRDError: Unsupported format, or corrupt file: Expected BOF record; found '<?xml ve'

For other reference, this excel file gets generated from a company website and it creates an excel file as well as an xml file. How can I open this excel file ?
Answer: I believe the file might not in proper xls form. Open the file in notepad to check. The "?xml ve" indicates that.
See this post for a similar situation.
Your file is probably really a .xml file, which is not supported by xlrd.


Oracle Equivalent of PostgreSQL CLUSTER

Question: PostgreSQL has the CLUSTER command to group rows physically on disk. By grouping on information where "neighboring" rows (for lack of a better term) are often accessed together, performance improves since fewer disk blocks need to be read in a given query. Does Oracle have anything similar? Would it even help performance on a large table that is almost never updated if there is such an option?
Comment: In Oracle they're called Index Organized Tables and they're very rarely used.
Answer: Similar concept in Oracle is called Index-Organized Tables (IOT).
Difference with PostgreSQL CLUSTER is that in PostgreSQL CLUSTER command reorganizes table once and later table still grows as it wants to. In Oracle IOT keeps its structure as ordered by index.
Unlike Phil I'm seeing IOTs now and then. The most often they are used when you need to retrieve many (think hundreds) rows by index.
Comment: But importantly only by the primary key, not by other indexed column. If you have a meaningful primary key then you might be selecting by range, but for a synthetic primary key the benefits would really be incidental (eg. because you want all of the rows entered on a particular day, and they naturally cluster by PK if it was generated by a sequence).
Comment: Of course, you can turn the primary key of the table into a unique key, and the unique key you want to "organize" on into the primary key. Any child tables will have to point their foreign keys to the unique key columns explicitly. But it's still not possible to organize on a non-unique index.
Answer: Oracle has index organized tables, b-tree clusters and hash clusters. The cluster implementation in Oracle support one or more tables stored in a same cluster. See AskTom for more details. Which is best for you depends on how you define "neighboring rows" and how do you access the data.
I have seen hash cluster to make significant improvements to performance, but it can be rarely used because the amount of keys must be specified when the cluster is created.
Comment: Thank you. On this question, I regret that I can only choose one answer.
Comment: There are also [indexed clusters](http://docs.oracle.com/cd/E16655_01/server.121/e17633/tablecls.htm#CNCPT88825) which are a little more practical since the number of keys is unlimited (though you need a rough estimate of the number of entries per key).
Comment: Yes, Oracle has indexed cluster. I used the term "b-tree cluster", which is not the official term.
Answer: The most similar Oracle functionality would be to recreate the table with the rows being ordered.
This could be performed online using DBMS_REDEFINITON, but you can more simply:
<code>Create table tmp_source_table
nologging
as
select * from source_table;

Truncate table source_table;

Insert /*+ append */ into source_table
select *
from   tmp_source_table
order by column1, column2 ... etc.
</code>
It would improve the efficiency of index range-based access methods where the table is accessed via an index on the ordered columns, unless or until the table gets disorganised by more rows being inserted. Updates would not affect this so much as Oracle does not normally move rows just because they are updated, as PostgreSQL does.
Index-organised tables, clusters, and partitioning all provide more permanent solutions for enforcing physical clustering of rows.

IOTs organise by the primary key values only, which is of limited use as you generally don't access a range of rows via a meaningless primary key.
Clusters organise by range, or simply co-locate identical values (hash clusters), and can do so for multiple tables. Hash clusters provide faster lookup than indexes -- typically one logical read -- and optimise single row lookups as well as ranges.
Partitioning physically colocates rows based on a range of partition key column values, on sets of values for the key columns, of on the hash value of key columns, or by reference to a column in another table.

Another associated technique is the use of Materialized Views, which can offer different physical clustering of rows to the original table via the use of the above techniques, with query rewrite being employed to choose the table with the most useful clustering.

Oracle Equivalent of PostgreSQL CLUSTER


Clear PowerShell while process is running

Question: Every online guide for clearing the PowerShell says to use the command clear, but what if I have a process currently running? On Mac OSX, I can use Cmd+K to clear the console at any point. Is there an equivalent command on Windows. For reference, I need this often when I am running a server and I want to trigger a client-side event and see what the server outputs from only that event.
Comment: CTRL + L clears the window but you need to try if it fits your needs (probably not!) because when PowerShell is running a command, it won't respond to anything else that runs in the foreground
Answer: There are two commands you can use namely cls or clear
Clear the output by typing and executing either one of the above mentioned commands in PowerShell Examples: cls or clear
https://www.carnaghan.com/knowledge-base/how-to-clear-the-screen-in-windows-powershell/
Comment: I don't think this works while a command is currently running


Navigate between loosely related classes based on naming convention

Question: In my current project we have many parts where we have something as follows:
var request = new ThingRequest {someId = };
ThingResponse response = dispatcher.Get<ThingResponse>(request);

Where dispatcher fetches a class with the name ThingRequestHandler that handles the actual logic.
public class ThingRequestHandler : RequestHandler<ThingRequest, ThingResponse>

This system is great for keeping it SOLID but I'm having trouble navigating easily.
Currently I use R# to goto class and -as I now the class name to follow convention- manually type the class name. This usually works but makes my head jump from thinking about the problem to thinking about a class name.
I would love to be able to navigate to my ThingRequestHandler from my dispatcher.Get line with one keystroke or click.
Is there a way Visual studio 2012, R# or any other plugin or macro would help me do this?
Answer: In R# 8+ they made a loads of improvements and especially to the navigation. They introduced CamelHumps which could be very useful in your case. For example you could navigate to ThingRequestHandler just by typing trh.
Comment: That is indeed the next best thing, was looking for more direct support though


Amount of recoil in a 357 magnum with a 5.5 inch barrel if using a 38 special cartridge

Question: I wanted a 38 special with a 4.75 inch barrel. Due to the rush on firearms and lack of mid-priced options, I purchased a 357 magnum/38 special with a 5.5 inch barrel. I have shot a 38 special with a 4.75 inch barrel before and the recoil is very manageable. Will I have that same manageability using the 357 magnum and a 38 special cartridge?
Comment: 3/4" will make a negligible difference as you may get a little extra powder burn but the added weight of the 357 frame and longer barrel will likely negate any increase in recoil. If anything i would guess you will notice a bit less.
Comment: My understanding is that a longer barrel = more recoil because more powder gets burnt in the longer barrel than with a shorter barrel, but it will depend on the load I guess. - I'll wait for a more knowledgeable person to answer.
Answer: It depends on the mass/weight of the gun. A 357 is likely to have thicker sections = more weight, so less recoil. But the longer barrel will increase recoil. It seems like it would not be much different.


Importance of coming on time for davening

Question: I'm looking for sources/inspiration about the importance of coming on time for davening. Not about being in the first ten, but just being there on time time. The more the better. Any help would be appreciated.
Comment: My grandfather literally wrote the book on this: https://www.amazon.com/Right-Time-Torah-Approach-Punctuality/dp/1937887243
Comment: There is a quote somewhere that you should arrive even before services begin so you can prepare yourself mentally for engaging in prayer.
Answer: I once heard a true story (it might have been in one of Rabbi Paysach Krohn's books).
There was this man who came late every day to shul. One day the Rabbi asked him, "I can see that you come to shul every day, maybe you could try and come on time".
He replied, "Who cares, the main thing is that I come in the end".
Several months later, the latecomer had a fire break out in his house. He frantically called the fire department who said they would arrive shortly. Finally after the house was ablaze for nearly an hour, the fire department came and managed to put out the fire. By this time, most of his possessions were burnt and the house was beyond repair. He angrily asked the firefighters who were on the scene, "Couldn't you have arrived earlier?"
He replied, "Don't complain, the main thing is that we came in the end."
This person told his Rabbi, from here I learnt the power of coming to shul on time, for if I miss even one minute, I am unable to make up what I missed. Every moment is precious and it is a shame I didn't listen to your mussar and that I had to learn the hard way.
Comment: We're expected to believe this is a true story?
Answer: The Shulchan Aruch (cited below) gives directions to the one who arrives late to the synagogue and finds that the congregation is already at the end of Pesukei D'zimrah. On that paragraph, the Mishnah Berurah (cited below) writes that ideally one should arrive early in order that one needn't skip any sections. The Mishnah Berurah contiues to quote that the Magid (an angel who shared Torah with Rav Yosef Caro) urged Rav Yosef Caro to arrive early to synagogue in order to pray all parts of the service in order, with no skipping. The Magid explained that the one who skips is mehapech hatzinoros. This contributor understands that to mean that the metaphysical channels through which our prayers ascend are disturbed.

כ' שו"ע (או"ח נב:א) אם בא לבהכ"נ ומצא צבור בסוף פסוקי דזמרה וכו' וכ' מ"ב (סק"א) אבל לכתחלה ראוי לבוא לבהכ"נ בהשכמה כדי שלא יצטרך לדלג כי כתבו הספרים שהמגיד הזהיר לבית יוסף לבוא לבהכ"נ בהשכמה כדי שיוכל להתפלל כסדר ולא בדילוג כי העושה כן מהפך הצינורות
Answer: A quote from the Kitzur Shulchan Aruch 1:4 (at the end):
עַל אַחַת כַּמָּה וְכַמָּה לַעֲבוֹדַת מֶלֶךְ מַלְכֵי הַמְּלָכִים הַקָּדוֹשׁ בָּרוּךְ הוּא, שֶׁיֵּשׁ לוֹ לְהִזָּהֵר לָקוּם בִמְהִירוּת וּבִזְרִיזוּת. וְהַמַּרְגִּיל אֶת עַצְמוֹ בַּדֶּרֶךְ הַזֶּה אַרְבַּע אוֹ חָמֵשׁ פְּעָמִים, לֹא יִכְבַּד עָלָיו אַחַר כָּךְ. וְהַבָּא לִטָּהֵר, מְסַיְּעִין לוֹ (סדר היום וסדור דֶּרֶךְ הַחַיִּים).
...How much more so should this apply for the service of the King of kings, the Holy One, Blessed is He, that you should be concerned to rise quickly and with alacrity. Once you accustom yourself to this practice four or five times you will no longer find it difficult, [as our Sages have said:] "He who makes an effort to purify himself is [Divinely] assisted in his efforts."
https://www.sefaria.org/Kitzur_Shulchan_Arukh.1.4?lang=bi&with=all&lang2=en
Answer: See masechet shabbos 119b where the Gemara states that "one who answers amen with all his might has the gates of Gan Eden opened for him" and one who answers yehei shmei rabba has evil decrees torn up even if he has the misdeed of idol worship". One who comes late to davening will likely miss out on numerous opportunities to answer amen and yehei shmei. People are often trying to find segulot for health, wealth, etc. people will pay thousands of dollars for pesicha at Neila or Maftir yona because it is stated as a segula in some seforim, yet the most basic 'segulos' that are stated in the Talmud are tread upon. If you could inspire a person to appreciate the opportunity that every amen presents, it will hopefully motivate to come to davening on time.


can i use the count value of a list in sharepoint to be displayed according to where i want it?

Question: usually the value of count is displayed at the top of the column,so is it possible to get the value of that count and display it anywhere else like in a html textbox or on a label on the same page?
Answer: This question was answered in this StackExchange question that has you editing the XSL files through SharePoint designer.
Answer: XSLT is one option, there are more.
I say CSR-Client Side Rendering on SP2013
But there is some undocumented (and maybe a bit dirty) trickery which works in both 2010 and 2013/Online.
Paste this Formula in a Calculated Column (in the List only, do not add it to existing Content Types), set the datatype to Number:
=""

datatype Number will have it execute as HTML/Javascript. But Microsoft disabled use of the SCRIPT tag in summer 2013, so we use a blank IMG to trigger an onload event. Ofcourse those 2 lines of JavaScript will be executed for every List Item.
Add a
 to the page, change the JS code to reference your DIV... et voila..
Note: The Javascript is executed INLINE, while the page is still loading. So Add the DIV above the List View WebPart! because all content below hasn't loaded yet.
More explanation at https://www.365csi.nl/vm365com/#/How


Update Google Maps with GIS data

Question: Several county residents have been contacting our GIS office to find out why they are not receiving packages or why the delivery person gets lost finding their address.  I know it sounds like an odd question to as GIS, but it turns out thier packages are being delivered by UPS, FedEx, etc. All of them use Google Maps to locate an address in our county.  I checked a few of the addresses in question and they are either non-existent or in the wrong location.  I also found several subdivisions where not a single road is showing up in Google Maps either.  Now I know I can submit a "suggestion" to Google for them to update the map, but I really do not want to do this several hundred times to correct all the errors I have found so far.
Is there a way to upload GIS data from the county in order to update their maps? If so, is there an app, interface, or procedure available to do so?
Answer: Yes, you can do this using Googles Geo Data Upload tool: https://support.google.com/mapcontentpartners/answer/9359673?hl=en#.

Update Google Maps with GIS data


iCloud has space but iCloud Backup says that I don't have enough to complete a backup

Question: I use 120 MB of iCloud storage space for iCloud Backup of my iPad & iPhone. There is still 4.8 GB free from 5 GB, but I have a notification in iPad's backup window that I'm lacking space to back up to iCloud and would rather not buy more space to back up today.
Comment: same happens for me....
Answer: This could easily be explained as the 120 MB of used data is likely for the data all the apps store in iCloud. Contacts, calendars, specific third party apps can have storage in iCloud. You can determine this by looking at the Manage Storage pane in settings app (see below).
The warning you describe comes up when the expected size of the next backup is greater than the available free space.
You can reduce the size of the expected backup on iOS (updated for iOS 16) as follows:

open the Settings app
tap your AppleID/iCloud avatar (first item, top of list)
tap iCloud
tap Manage Account Storage
tap Backups
tap the name of the device in question (it usually says this iPod touch, this iPhone or this iPad to help if you have many devices connected to iCloud)
look at Next Backup Size
toggle off any unwanted apps from the list below

If that is less than the available space, you may need to contact Apple support to have your account fixed on the server side. In most cases, you can toggle off the largest few items and then attempt a backup when the estimate is less than the available space.

Once the backup is complete, you can tune the backups or manage your space as needed on iCloud.

On iOS 15 I did have an open case with Apple. I have a 256 iPhone that refuses to back up to iCloud or a Mac with out of space errors and it's not possible since the phone has less total space than either destinations have free. Once I enabled my support pin with them, it did show podcasts needed to back up 590 GB of data (on a 256 phone) so I disabled that from backup and then it backed up successfully. Once the "partial" backup was done, I re-enabled podcasts app to backup and it had a reasonable amount of space (less than 500 MB) and the situation was sorted while preserving all data to iCloud.
Comment: I'm on iOS 8, for me it was icloud>> storage >> manage storage >> Backups --> next Backup size:
Answer: In my case, I have the problem that iCloud estimates my data usage to be 10.9GB, while I have chosen to back up maybe only 1-2GB. If I turn, for example, camera roll off or on again, it doesn't matter.
iCloud estimates this wild, high, far too much space to make a backup, and I even deleted my previous backup and started new, to be sure to 'reset' everything, but it doesn't help!
My iPad only uses 2.2 GB, I have 2.8 left for the phone, and select 'no backup' for most, but the mail and a few programs like Skype and so on, altogether far less than "10.9" GB, probably only 1-2GB.
This problem seemingly happened before, the iCloud backup grow out of control, like a classical Windows installation.
However, I now see that, as I deactivate more and more smaller applications, of a few kb size of their data, that the total usage decrease much more than these few kb which are stated for each app.
This means that Apple seemingly underreports how much data they backup, from each app, or maybe the system counts too much, I don't know.
It is not possible to deactivate all the apps at once, in the hope to get down to the 17MB which is stated on the first page, (e-mail and settings), so there will be a lot of job to make this work again... :-/
Comment: I had this problem forever. Went to the Apple Store to see if they had a suggestion, they just said buy more space... After messing around with this over the past year off and on when it annoyed me, I figured out that in my case it's because of my Messages history. Which doesn't show up in the Manage Storage> Info screen. I went to Settings > Messages and turn the message retention down to a year instead of Forever and it dropped from 8.3GB to 3.6GB. So that was my solution.
Comment: I'm having the same problem.

Just recently deleted and backed up again. It's showing as if I was backing up 2.7GB of data, but if you look at "Next Backup" it's shown much smaller, like 800MB. All the items I have sum those 800MB, but still the final backed up size is much bigger.

Even deleting stuff from those 800MB, still got me near 2.2GB, but no less than that. Backups also take so much more than they should considering I've got good connecting, not so old iPhone and so little data…
Answer: The solution where you disable certain data from being backed up in iCloud is not really a solution but merely a workaround. Unfortunately, the real solution would imply you paying for iCloud's yearly subscription charges.
Or keep your iPhone backup out of the cloud an on your PC instead: There is not enough iCloud storage available. How to backup iPhone
Alternatively, keep the Camera Roll under iCloud backup settings disabled as that eats lots of space and back up your iPhone to your PC via iTunes. This way you don't lose the backup of your Camera Roll.
Comment: I agree that disabling data buckets is a workaround, but it's extremely effective for triaging when one specific container is corrupt and for preserving the data someone needs to get backed up before wiping a suspect phone and reloading the most important backup. Good points on local backup as another workaround or permanent alternative.
Answer:
Are you sure you only need 120 MB for iCloud Backup?
Check the size of the 'next backup' in iCloud Backup on your device. Make sure that it's less than the free space of your iCloud account.
Are you checking the storage of the correct iCloud account?
Make sure that you're looking up the free space of the correct iCloud account if you have multiple. Only the main iCloud account can be used for iCloud Backup — accessible through Settings → iCloud.


How can I generate UML diagrams from C# code written in Visual Studio 2012 into Visio 2010?

Question: I am trying to find a way to generate UML diagrams (sequence diagrams, class diagram, etc) from my C# code written in Visual Studio 2012.
I saw a link on http://office.microsoft.com/en-us/visio-help/about-reverse-engineering-code-to-the-uml-HP001208803.aspx that I could bring my Visual Studio project into Visio.
But its first part where it says "In the Visual Studio environment, reverse engineering is activated from a command on the Project menu." doesn't work for me because I cannot find a reverse engineering option under the Project menu.
How can I generate UML diagrams from C# code written in Visual Studio 2012 into Visio 2010?
Answer: Microsoft no longer considers Visio to be a software engineering tool. There was a version known as "Visio for Enterprise Architects", which had this integration with Visual Studio. It was available with the highest-end edition of Visual Studio.
I believe it was last supported with Visual Studio 2005, though that might have been 2003.
Visual Studio Ultimate now has its own built-in UML features which do not rely on Visio.
Comment: This is unfortunate, as the built-in UML features do not support C++ reverse engineering. I now have the same problem as xEnOn (but with C++ instead of C#), and from what you're saying it sounds like there's no way to achieve what I want with either VS2012 by itself or in combination with Visio?
Comment: Have you checked Visual Studio 2012 Update 1? They added a bunch of C++ features, and maybe UML support for C++ is one of them.
Comment: Yes, I've tried Update 1. Still no C++ support, sadly. I do like a lot of the other C++ features they've added though (new item templates, GPU support, unit test framework, etc.).
Comment: Digging through Microsoft site, I find references to using Visio 2003 and Visio 2007 to reverse engineer code into UML. 2003 instructions found at: http://office.microsoft.com/en-us/visio-help/about-reverse-engineering-code-to-the-uml-HP081550745.aspx 2007 Reverse Engineering instructions (for VB6 using Visio 2007) found at: http://office.microsoft.com/en-us/visio-help/reverse-engineer-microsoft-visual-basic-6-0-source-code-HP001208946.aspx
Comment: Why do you care about ancient versions of ancient tools? Those are not current.
Comment: @JohnSaunders There are plenty of circumstances that may require one to use specific versions of specific software. Whether or not they fall under some subjective definition of "current" is irrelevant.
Comment: @b1nary: "current" is a very objective measure, "not current" even more so. 2007 << 2015, and UML 1.2 is not what was meant when your boss says "UML diagram".
Answer: Blast from the past. It's been a while since I've reverse engineered anything into UML so my knowledge may be outdated.
In any case, as far as I remember, code reverse engineering using Visio is a Visio feature not a Visual Studio feature, thought some versions of Visual Studio have their own modelling features.
In order to use Visio reverse engineering you need make sure the Visio UML addin is installed (it should be available in Professional and above versions of Visio, but may not be installed by default.)
Here's a rather old step by step of the process for an old version of Visio and Visual Studio. I don't think the process has changed that much (though obviously the languages supported have changed.)
In any case I never liked Visio for UML (truth be told I never liked Visio.) I rather liked Sparx System's Enterprise Architect for modelling, and their reverse engineering was quite good when I used it on .Net 2.0. I don't know how their current version copes with the newer features. I also like their "from scratch" modelling environment better.
Finally keep in mind UML is supposed to be a modelling not a programming language. I.e. it is meant to convey the high level design so the overall architecture of a solution can be more easily understood; or to model key dynamic interactions, again, so the implemented or proposed solutions to the modeled problem can be more easily understood.
Reverse engineered UML diagrams often have too much information for them to be useful, and it is difficult in any case to translate the precise semantics of a specific language into UML. You may be better off creating diagrams from scratch. Other than deployment and package diagrams, it should be understood that UML diagrams represent a high level overview or specific high level dynamic interaction representation, not an as-developed representation.
Answer: This depends on which version of the product you are using. I have Visual Studio Professional 2012 and I don't see this option. This makes sense if you look at the product features. If, however, you look at the product features of Visual Studio 2012 Ultimate, you will see UML modelling, and various other visualisation tools.
Comment: True, but this UML Modeling feature is not related to Visio, which is what the question was about.
Answer: Visual Studio 2010 non-Ultimate version allowed for this UML generation by using Feature Pack, which hasn't been developed for Visual Studio 2012 yet.  As Dominic mentioned (he beat me to it), Visual Studio 2012 Ultimate should allow for this though.
Answer: Visual Studio Ultimate 2012 can generate very nice sequence diagrams for C# code when you just select a member (method name); and it fails constantly at my place if I do the same for in VB code.
This in contrast to Enterprise Architect from Sparx, the most advanced CASE tool for UML and other modelings AFAIK.


Upgrade my MacBook Pro

Question: I want to upgrade my existing MacBookPro to the current one in the market. Is it possible to upgrade the hardware configuration, like RAM, HDD.
Comment: Which model of MacBook Pro do you have?
Comment: 13inch Mid 2010. Macbook 7
Answer: For comparison, this is the spec for your machine. The current non-retina 13inch is the mid-2012.
It's not possible to upgrade your machine to be the equivalent spec of the current one. e.g. the CPU can't be upgraded, the more recent models have Thunderbolt etc.
However, you can upgrade the RAM from 4GB to 8GB, and you can replace the HDD with a much faster SSD.
The SSD will make a big different to the performance of the machine and the memory upgrade is almost certainly worthwhile too.
Answer: Laptops, especially Apple laptops, are generally designed using the best components and technology available at the time. So, in order to fully upgrade your MacBook to the current model, you'd need to trade up and buy a new MacBook. This is especially true now that all componentry is being soldered to the logic board, to save space, make room for the battery, and greater use of solid state memory.
The 2010 MacBook Pro gives you at least a few options of varying difficulty. RAM is the easiest to get to, and is detailed here on Apple's support pages. Your MacBook "supports" 8GB of RAM, in that your machine has two SO-DIMM slots, and when the system was designed, the highest-density modules available were 4GB--but, it should actually be capable of using 16GB of RAM, since 8GB modules are now available (memory speed is backwards-compatible, and OS X has no problem addressing this much memory).
The Hard Drive is pretty much the only other accessible component, and it is a bit more difficult to access than the RAM, so do make sure you know what you're getting into beforehand. You won't get a performance increase from upgrading your HD unless you cross-grade to an SSD, which might actually be less capacity than what you have now.
If you're really feeling adventurous, OWC will sell you a DIY kit to actually replace your optical drive with a second HD or SSD. Rumor has it you could even use this to build your own Fusion drive in your MBP setup, for the best of both worlds in terms of storage capacity and speed.

Upgrade my MacBook Pro


Which scholars argue that for art to be art, it must be for art's sake?

Question: I understand this is partially supported by Nietzsche, but do others agree or adamantly disagree with this position? If so who?
Answer: One main thinker with this point of view is Kant, who argues in his Critique of Aesthetic Judgment that one of the main defining characteristics of art is that it has does not have an external purpose --a point of view agreed with by (among others) William Kennick in an influential essay otherwise critical of traditional aesthetics called "Does Traditional Aesthetics Rest on a Mistake."
However, this position is actually a more recent innovation, with older thinkers such as Plato and Aristotle taking it for granted that art played a specific function in human life.
EDIT: I should clarify, based on the comment below, the argument being advanced by Kant and Kennick, among others, is not that art cannot be devoted to external purposes, but that serving such a purpose has nothing to do with what makes it art.
Comment: Such an argument makes all commissioned works, or works done for sale, non-art. Well that has just eliminated the majority the content of most major galleries.
Comment: @ConradTurner Whether it's true or not, that's not implied by what Chris Sunami stated. Even if you considered it to lessen the artistic power, it still does not imply it is non-art.


Subscript font size in Emacs TeX mode

Question: In Emacs 23 TeX mode, subscripts and superscripts are displayed in smaller fonts. How can I configure Emacs to turn off this feature and use the same font size for all input?
Comment: Are you able to review the new answer that was posted for its validity? Since there's so much time that has passed, there may be new things that are better.
Answer: This is easy to turn off using
(setq tex-fontify-script nil)

in .emacs. You can also access it using customize-mode <ENTER> tex-mode <ENTER> and scrolling down to "Tex Fontify Script" and clicking on "Toggle".
There are also two control variables which you can set to neutral values to disable the fontification, for example if you just want to make it smaller without raising or lowering, or if you want to keep the raising and lowering without it getting smaller.
; This sets the amount of raising/lowering
(setq tex-font-script-display '(0 0))
; This sets how small the font is made relative to the text
(setq tex-suscript-height-ratio 1)

(Note: suscript is not a typo, it is used to mean "superscript" and "subscript" by tex-mode.)
As with tex-fontify-script, both of these variables may be customised using customize-mode.

Now, as far as I've been able to figure out, customising the font face with customize-face doesn't seem to work. The height can be altered, but the raising and lowering values are overridden by the code in tex-mode, which raises or lowers the text regardless. This happens in the function tex-font-lock-suscript. If there is a way to turn that off by setting a custom face then that would be another way of doing this job, but I wasn't able to figure out the correct value.

Subscript font size in Emacs TeX mode


Enumerating number of solutions to an equation

Question: How do you find the number of solutions like this?
$$x_1 + x_2 + x_3 + x_4 = 32$$
where $0 \le x_i \le 10$.
What's the generalized approach for it?
Answer: First you calculate the number of solutions in non-negative integers without worrying about the upper bound of $10$ on each variable. This is a standard stars-and-bars problem, reasonably well explained in the Wikipedia article. Then you use the inclusion-exclusion principle to get rid of the unwanted solutions.
In this case the first step gives you a preliminary figure of $$\binom{32+4-1}{4-1}=\binom{35}3=6545\;.$$
Now count the number of solutions that make $x_1$ too big. This means that $x_1\ge 11$, so the excess over $11$ in $x_1$ plus the values of $x_2,x_3$, and $x_4$ must add up to $32-11=21$. Each of these unwanted solutions therefore corresponds to a solution in non-negative integers to the equation $y_1+y_2+y_3+y_4=21$, and there are $$\binom{21+4-1}{4-1}=\binom{24}3=2024$$ of those. In fact there are $2024$ unwanted solutions for each of the four variables, so our next approximation is $6545-4\cdot2024=-1551$ solutions.
Of course this obviously isn't right. The problem is that some solutions exceed the cap of $10$ on more than one variable. Every solution that exceeds the cap on two variables was removed twice when we subtracted $4\cdot 2024$ and therefore has to be added back in. Consider a solution that has both $x_1$ and $x_2$ greater than $10$. Then the excess in $x_1$, the excess in $x_2$ and the values of $x_3$ and $x_4$ must sum to $32-2\cdot11=10$, so we're essentially counting solutions in non-negative integers to the equation $y_1+y_2+y_3+y_4=10$, of which there are $$\binom{10+4-1}{4-1}=\binom{13}3=286\;.$$ There are $\binom42=6$ pairs of variables, so we must add back in $6\cdot286=1716$ to get a better approximation of $-1551+1716=165$ solutions.
It's impossible for more than two variables to exceed their quotas, since $3\cdot11=33>32$. Thus, no further corrections are needed, and the final answer is $165$ solutions meeting the original boundary conditions.
Answer: If you consider the following function
$$
f_{\rm dim}(\epsilon)=\left(\frac{1-\epsilon^{11}}{1-\epsilon}\right)^{4},
$$
and expand at $\epsilon=0$ then coefficient in front of $\epsilon^{32}$ will give you the correct result, 165.
Explanation of why this works is given in my answer to This question.
The method can be obviously applied to generic case: Suppose there is equation $$\sum_{i=1}^n x_i=M$$ and we demand constraints $\lambda_i\leq x_i\leq \Lambda_i$. Question is how many solutions are there?. The answer is to consider
$$
f_{\rm dim}(\epsilon)=\prod_{i=1}^n\frac{\epsilon^{\lambda_i}-\epsilon^{\Lambda_i+1}}{1-\epsilon}\,,
$$
expand this function at $\epsilon=0$ and find the coefficient of expansion at $\epsilon^{M}$.
Definitely, this method is a very efficient approach to use on a computer, much faster than generating all possible permutations as was suggested in another answer to your question.
For your particular example, this method can be also used to perform a computation by hands (though it might be not the case in generic situation). The required coefficient is given by the contour integral  $\oint\frac{d\epsilon}{2\pi\,i}\frac{f_{\rm dim}(\epsilon)}{\epsilon^{33}}$ around the origin. But this integral can be also computed by residue at $\epsilon=\infty$ (note that at $\epsilon=1$ there is no pole). For the purpose of finding $1/\epsilon$ term in the large $\epsilon$ epxansion, the replacement $1-\epsilon^{11}\to-\epsilon^{11}$ can be used:
$$
\left(\frac{1-\epsilon^{11}}{1-\epsilon}\right)^{4}\frac 1{\epsilon^{33}}\simeq\epsilon^{11\times 4-33}\frac 1{(1-\epsilon)^4}=\epsilon^7\left(\frac 1{1-\epsilon^{-1}}\right)^4\to\epsilon^7\times\epsilon^{-8}\binom{8+4-1}{4-1}=\frac{165}{\epsilon}
$$
After all, the answer is computed by a single Binomial coefficient $\binom{8+4-1}{4-1}$. This gives us a possibility to guess a nice trick. Consider a solution to the equation
$$
y_1+y_2+y_3+y_4=8
$$
with the only constraint $y_i\geq 0$. Then $x_i=10-y_i$ will be a solution to the original equation. It is easy to check that this is one to one map (with given boundary requirements), so $\binom{8+4-1}{4-1}$, the number of solutions for equation on $y$'s, is the desired answer.
Answer: In GAP, they can be computed via:
<code>R:=RestrictedPartitions(32,[0..10],4);
S:=Union(List(R,r->Arrangements(r,4)));;
Size(S);
</code>
which gives 165.
Note that the first step generates unordered partitions of 32 into 4 parts, which I call $R$.  Then I need to permute them in all possible ways, and take their union to create all possibilities, $S$.
Answer: To maximize the value of this q&a I will assume that, by your asking for a "generalized approach", you were requesting that it work for any...

# variables (NOT only 4) $=v$.
Rhs (NOT only 32) $=n$.
Lower bound (NOT only 0) $=l$.
Upper bound (NOT only 10) $=u$.

My generalization will utilize generating functions (GF)s, coefficient extraction, power series, & evolve over 3 phases (w/ the results of phase 2 & 3 providing a solution to your particular example)...

Suppose we were solving (a problem like yours but w/o the upper limit you set @ 10)...
$$
card\left(A\right) = card\left(\left\{(x_1,x_2,\ldots,x_v)\in\mathbb{W}^v : x_1 + x_2 + \cdots + x_v = n\right\}\right)
$$
We have a linear equation of $v$ variables, w/ every coefficient equal to 1, so...
$$
card\left(A\right) = \left[x^n\right]\left(x^0 + x^1 + \cdots\right)^v = \left[x^n\right]\left(\frac{1}{1 - x}\right)^v
$$
Suppose we were solving (a problem like yours but w/ an upper limit)...
$$
card\left(B\right) = card\left(\left\{(x_1,x_2,\ldots,x_v)\in A : x_i\leq u \right\}\right)
$$
We have the same setup (as we did in 2) but w/ an upper limit, so...
$$
card\left(B\right) = \left[x^n\right]\left(x^0 + x^1 + \cdots + x^u\right)^v = \left[x^n\right]\left(\frac{1 - xx^u}{1 - x}\right)^v
$$
My final generalization is but a shadow of its most generalized form (made possible/easily-obtainable through the use of GFs): Suppose we were solving (a problem like yours but w/ arbitrary lower AND upper limits)...
$$
card\left(C\right) = card\left(\left\{(x_1,x_2,\ldots,x_v)\in\mathbb{Z}^v : x_1 + x_2 + \cdots + x_v = n\;\land\;l\leq x_i\leq u\right\}\right)
$$
We still have a linear equation of $v$ variables w/ every coefficient equal to 1, so...
$$
card\left(C\right) = \left[x^{n - vl}\right]\left(x^0 + x^2 + \cdots + x^{u - l}\right)^v = \left[x^{n - vl}\right]\left(\frac{1 - xx^{u - l}}{1 - x}\right)^v
$$

As mentioned in the beginning, the solution to your particular example is given (respectively) by the result of phase 2 or 3...
$$
\left[x^{32}\right]\left(\frac{1 - xx^{10}}{1 - x}\right)^4
= \left[x^{32 - 4\cdot 0}\right]\left(\frac{1 - xx^{10 - 0}}{1 - x}\right)^4 = 165
$$

I still consider myself the noob of noobs wrt generating functions but I knew enough to solve this simple example. I intend to keep studying them as they are a very powerful tool (I would even say THE most powerful tool wrt solving combinatorics questions) &, if your interested, this doc taught me everything I know.


Installing GarageBand on OS X Mountain Lion?

Question: I've recently downgraded to 10.8.5 as I had been having trouble getting Mavericks to work with my TASCAM US-1641 audio interface. I tried to reinstall GarageBand and try out my interface again only to find that the version of GarageBand in the App Store is only for Mavericks. Is there any way to download an old version? Which version would I need for Mountain Lion? Any help would be appreciated!
Answer: I found another Macbook that already had GarageBand running on and copied GarageBand right out of the Applications folder and into the shared folder of my newer computer that needed it.  My new machine also runs Mountain Lion.  Once it's in the shared folder of the new computer, then move it to the Applications folder of the new computer.
Comment: You might also look in /Library/Application Support/GarageBand for loops to copy. Most installations have about 5 GB of samples there from that era of Garage Band program.
Comment: also, there is often an old version of Garageband on computers that have upgraded. Mine was moved into a folder "Garageband 6.0.5"


Products not appearing under content in admin in Drupal Commerce

Question: I am importing products using Commerce Feeds.  The products appear just fine on the front end and via Store > Products in the admin.  However no products appear under Content in the admin area.  I have tried clearing out the database, re-importing, re-indexing, flushing caches - nothing works.
Also this is bizarre and seemingly un-related, however I noticed it around the same time I realized my products were not appearing in the admin - there is a strange whitespace above my admin menu bar - which only appears on the Content page (also coincidently the page giving me trouble.)
Using Commerce Kickstart (commerce_kickstart-7.x-2.0-rc1) (Would love to upgrade to the latest release but I am unsure how to do this without losing a great deal of work.  I have not found a good upgrade document - please chime in if you know something I don't!)
Comment: Oh, before I get this question - I am importing both products and product display.  I can see all of the products I have imported with the type of "product_display" when I query the node table.  I just don't see them in the admin area.
Answer: I feel kind of stupid now.  I edited the admin/content view and saw there was a filter criteria which caused it to not display nodes of type "product_display."  Evidently this is intentional behavior.  I am guessing you are only supposed to manage products from within the store tab.  Still wish I could figure out the cause of the phantom whitespace at the top though.


Is playing Age of Empires Halal?

Question: It's a strategy video game. Please only those who knows the gameplay answer this.
Answer: Bismillah Hir Rahmaan Nir Raheem
As Salaamu 3laykum,
I hope you are doing well. So here are the following ahadith that mention about images (animate beings).
Hadith #1

Abu Talha, a companion of ALLAAH's Messenger (ﷺ) and one of those who fought at Badr together with ALLAAH's Apostle told me that ALLAAH's Messenger (ﷺ) said. "Angels do not enter a house in which there is a dog or a picture" He meant the images of creatures that have souls. (Bukhari)

Hadith #2

"The Messenger of ALLAAH [SAW] said: 'Whoever makes an image will be commanded on the Day of Resurrection to breathe the soul into it but he will not be able to do so.'" (Nisai)

Hadith #3

'Aishah said: "The Messenger of ALLAAH [SAW] went out, then he came in, and I had hung up a curtain on which there were (images of) horses with wings. When he saw it, he said: 'Get rid of it.'" (Nisai)

Hadith #4

"Jibril, peace be upon him, asked permission to enter upon the Prophet [SAW] and he said: 'Come in.' He said: 'How can I come in when there is a curtain in your house on which there are images? You should either cut off their heads or make it into a rug to be stepped on, for we Angels do not enter a house in which there are images.'" (Nisai)

Age of empires uses full figures in the game. The game involves moving figures which would be impermissible. We should all abstain from these types of games including those movies that are animated. Now an exception is made if this were a kids game under a certain age. The permissibility can come from these ahadith:

Aisha (Peace and Blessings Upon Her) said: I used to play with the dolls in the presence of the Prophet, and my girl friends also used to play with me. When ALLAAH's Messenger (ﷺ) used to enter (my dwelling place) they used to hide themselves, but the Prophet would call them to join and play with me. (Bukhari)

When the Messenger of ALLAAH (ﷺ) arrived after the expedition to Tabuk or Khaybar (the narrator is doubtful), the draught raised an end of a curtain which was hung in front of her store-room, revealing some dolls which belonged to her. He asked: What is this? She replied: My dolls. Among them he saw a horse with wings made of rags, and asked: What is this I see among them? She replied: A horse. He asked: What is this that it has on it? She replied: Two wings. He asked: A horse with two wings? She replied: Have you not heard that Solomon had horses with wings? She said: Thereupon the Messenger of ALLAAH (ﷺ) laughed so heartily that I could see his molar teeth.

Have a Nice Day!

Note #1: If you downvote my answer, please be courteous and say why you downvoted in a comment below.
Note #2: This is my own personal answer that I have derived from what I have researched.

Is playing Age of Empires Halal?


Recover remix deleted contract and BNB

Question: I deployed.. added funds... nothing happened. I went to another tab in chrome then came back and noticed metamask was disconnected. I reconnected deployed the same contract left it overnight but nothing. I deleted the contract which i have just realised i may now not get back the .4 bnb i deposited into that contract. I deployed again but did not fund as i though i already funded but still nothing. I think my chrome ad blocker may have something to do with this. How can i get back my .4bnb and my deleted contract?
Answer: Most contracts currently receiving BNB cannot do anything with them, as the BNB received cannot be withdrawn. In order for us to understand whether it is possible to recover or not I need to see your contract and the hash of your transaction.
Please provide the hash involved, please.

Edit: my answer on 02/16/2021:
Thanks for providing more information and the hash.
I analyzed your TXID and also found the other transaction of the other 0.2 BNB:
https://bscscan.com/tx/0x66b3a3846f1e4824b32c55c7c959002af18b2ef37da308af9ef2b4c95b310cc1
You would have used flash loan contracts on mainnet, but unfortunately the contracts are from scammers. The money that goes into these contracts is diverted to another address: https://bscscan.com/address/0x896a04da39500882652c0de2cab8d806338505e1
The scammer who owned the above external address stole 4.1 BNB from victims.
The part of the code that diverts your money is statements that an alleged route address is on the IFPS or that a library is on the IFPS. Went in there and never comes back.
My advice:
Always be very careful with codes that appear on the internet, especially when they are not from reliable sources and make promises of big gains.
There are many scammers promising big gains with flash loan trades using dangerous contracts, but they are nothing but scammers.
First review all the code to see if there is something about embezzlement, then try to implement and study it on test net or talk to an expert when real funds are involved.

Recover remix deleted contract and BNB


Minimizing Perimeter of a quadrilateral

Question: Let us say that we are given a quadrilateral where the diagonals are congruent and fixed at a certain length, and the angle between the two diagonals are fixed. How would you prove that the minimum perimeter is achieved when the quadrilateral is a rectangle? I know it when diagonals aren't fixed at a certain length, one can prove it is a square by considering consecutive sides. However, when the length isn't convenient, and on top of that FIXED, the conditions are different, and you cannot do the same argument. Any help on how to convince/prove to me that the rectangle minimizes the perimeter?
Answer: I just realized that if, in a parallelogram, the diagonals have the same length (I think this is what you mean by congruent), it is necessarily a rectangle !
Maybe, I haven't well understood your question. In this case, could you made it more explicit by going directly to the question without explaining the origin of it (which confuses the reader) ?
Comment: Hello JeanMarie, I was just asking, given that a quadrilateral has congruent and fixed diagonal lengths, and a fixed angle between the two diagonals, prove that the minimum perimeter is achieved when the quadrilateral is a rectangle.
Comment: I realize with your remark that I haven't answered to your question but to another one. I am going to re-work on the first solution I had in mind.
Answer: Call $a,b,c,d$ the vertices and view them as vectors in $\mathbb R^2$. Call $m,n$ the midpoints of the two diagonals $\overline{ac}$ and $\overline{bd}$. Finally, suppose that the baricenter $(a+b+c+d)/4$ is the origin. Then it is easy to check that $m=-n$ (because the baricenter coincides with the midpoint between $m$ and $n$). In this way you can write
\begin{align}
a&=m+v\\
b&=-m+w\\
c&=m-v\\
d&=-m-w
\end{align}
where $2v=a-c$ and $2w=b-d$ are the diagonals. Now
\begin{align}
&\overline{ab}=|a-b|=|2m+(v-w)|\\
&\overline{bc}=|b-c|=|2m-(v+w)|\\
&\overline{cd}=|c-d|=|2m-(v-w)|\\
&\overline{da}=|d-a|=|2m+(v+w)|
\end{align}
and summing the two opposite pairs we obtain by triangle inequality that
$$\overline{ab}+\overline{cd}=|2m+(v-w)|+|2m-(v-w)|\geq 2|v-w|$$
and
$$\overline{bc}+\overline{da}=|2m-(v+w)|+|2m+(v+w)|\geq 2|v+w|,$$
and summing
$$Per(abcd)\geq 2(|v+w|+|v-w|).$$
Since the length of the diagonals is the same and the angle between them is fixed, then $2(|v-w|+|v+w|)$ is fixed and equal to the perimeter of the rectangle with that diagonals. Moreover this is basically the only case, because the equality case holds in both inequalities if and only if $\{m,v-w,v+w\}$ are linearly dependent, and that's not the case unless $v,w$ are linearly dependent, which corresponds to the trivial case where the angle is zero and can be dealt with separately.
Comment: Thank you very much for your help! I have a question, how is 2(|v+w|+|v-w|) fixed ?
Comment: @JaharMehru Because the diagonals have fixed length and angle between them. Therefore $|v+w|=2 l \cos\frac{\theta}{2}$ where $l=|v|=|w|$ is the length and $\theta$ is the angle in between. Similarly $|v-w|=2 l\sin\frac{\theta}{2}$.
Comment: Did you come up with this yourself, or did you originally learn it from somewhere else? It would be nice if I could use this with an reputable citation for a contest I'm doing.
Comment: @CJDowd When working with polygons, writing things as vectors (or complex numbers) is a common method for instance in olympiad problems. It can spare making heavy computations with trigonometric functions. I don't think there's really a reference for this though...

Minimizing Perimeter of a quadrilateral


Short story from many years ago where the two main characters merge into one

Question: The only thing I remember is that the two main characters are lovers (perhaps one is an alien?) and they merge into one entity at the end of the tale.  "It" pours itself a cup of coffee at/near the end.  I read it in the 1960's/1970's, but it may have been written before then. Anyone know this piece?  Thanks.
Comment: Your question is very short of details. Why not have a quick read through [this checklist](http://meta.scifi.stackexchange.com/a/9337/20774) and see if you can add some more.
Comment: I remember this one. I think it might have been answered before.
Answer: The Compleat Consummators by Alan E Nourse.
It is about a dating agency who promise a perfect match.

"One hundred per cent compatibility on all levels, or your money is
refunded and the alliance annulled."

Something happens to the couple that are matched:

"Something's happening!"
"Something's happening!"
"HELP..."
There was silence then, with only the echos of a strangled scream.
   After It had jelled for a while, It got up from the sofa and went into
the kitchen to make a pot of coffee.


Difference between "technically possible" and "physically possible"?

Question: Do you think these expressions can be used interchangeably? I find little or no differene between the two meanings. Does this question need more context?
Comment: Yes,surely it needs! :)
Comment: "Physically possible" is also used sometimes as a hedge. It is physically possible for all the water molecules in a pool to move suddenly to one side of the pool.
Comment: _Technically possible_ is a hedge, meaning 'possible, but only under certain technically-specified (but practically irrelevant) definitions'. _Physically possible_, however, is compositional, meaning 'possible according to the laws of physics'.
Comment: I agree.  They are sometimes used interchangeably, but not always; more context is needed.
Answer: Speaking from the eastern side of the Pond, I would understand them as being different:

Technically possible : theoretically possible, but may not be actually possible.
Physically possible : actually possible; possible in practice.
Answer: When you say 'technically possible' you mean that it is something that can be done, if you just go by the book. Like, according to the manual of instructions, you can make it happen. Usually this term is used when the truth of the matter is that, whatever the book says, it actually cannot be done. So in a way, it's a non-answer.
To say something is 'physically possible' is just to talk about the mechanics of the operation. There is no consideration given to other relevant factors. Like, for example, you can say that it is physically possible for a child to crawl through a 100-foot-long sewer pipe which is big enough to accommodate the child's body. This doesn't mean that it is actually possible because there are other considerations like whether the child would have the courage to do that, especially if the sewer pipe in question is totally dark and probably infested with mice and other creepy-crawlies, not to mention that it would very likely also be partly filled with stinking sewage.


Send As Distribution Group Email Address?

Question: We have a Small Business Server 2003, with a support distribution group.  Is it possible to allow members of a distribution group, send emails from the group email address?
Answer: You need to grant the users the "Send As" permissions. Not sure how to accomplish that on SBS 2003, but on Exchange 2003 you will:

Start the Exchange version of Active Directory Users and Computers
From the View menu choose Advanced Features.
Right click the user who wants to let other people send messages on his behalf and select Properties.
Select the Security tab and click Advanced.
Select the Permissions tab and click Add.
Enter the users who require the Send As permission, then click OK.
You will see the list of permissions. Make sure that "This object only" is selected for the apply field, then scroll to the bottom and select the Send As permission. Click OK.
OK the Advanced security dialog box, and OK the User Properties window to close.
Answer:
Open Active Directory Users & Computers
Activate "Advanced Features" in the View menu
Find the distribution list you want to send as
Open the properties and go to the Security tab
Add the user or group in question
Check the "Send As" permission
OK your way out

There is by the way a difference between "Send As" and "Send on Behalf Of". In the latter you can see which mailbox did actually send the mail, with "Send As" - and the above procedure - the message appears to come directly from the user that you granted access.
Answer: Yes.  You just enter the name of the list in the From: field in a new message.
Comment: Tried using the From: field, but I get "You do not have permission to send to this recipient" email from the server.


Dwork's use of p-adic analysis in algebraic geometry

Question: Using p-adic analysis, Dwork was the first to prove the rationality of the zeta function of a variety over a finite field. From what I have seen, in algebraic geometry, this method is not used much and Grothendieck's methods are used instead. Is this because it is felt that Dwork's method is not general or powerful enough; for example, Deligne proved the Riemann Hypothesis for these zeta functions with Grothendieck's methods, is it felt that Dwork's method can't do this?
Answer: The premise of the question is not correct.  Dwork's methods (and modern descendants of them) are a major part of modern arithmetic geometry over $p$-adic fields, and of $p$-adic analysis.
You could look at the two volume collection  Geometric aspects of Dwork theory to get
some sense of these developments.
Just to say a little bit here: Dwork's approach led to Monsky--Washnitzer cohomology,
which in turn was combined with the theory of crystalline cohomology by Bertheolt to develop the modern theory of rigid cohomology.  The $p$-adic analysis of Frobenius actions is also
at the heart of the $p$-adic theory of modular and automorphic forms, and of much of the machinery underlying $p$-adic Hodge theory. The theory of $F$-isocrystals (the $p$-adic analogue of variations of Hodge structure) also grew (at least in part) out of Dworks
ideas.
To get a sense for some of Dwork's techniques, you can look at the Bourbaki report  Travaux de Dwork, by Nick Katz, and also at Dwork's difficult masterpiece  $p$-adic cycles, which has been a source of insipiration for many arithmetic geometers.
In some sense the $p$-adic theory is more difficult than the $\ell$-adic theory, which is
why it took longer to develop.  (It is like Hodge theory as compared to singular cohomology.
The latter is already a magnificent theory, but the former is more difficult in the sense that it has more elaborate foundations and a more elaborate formalism, and (related to this) has ties to analysis (elliptic operators, differential equations) that are not present
in the same way in the latter.) [For the experts: I am alluding to $p$-adic Hodge theory,
syntomic cohomology, $p$-adic regulators, Serre--Tate theory, and the like.]
Comment: Nice answer!  As for the bunny's specific question, you could perhaps add that in the last few years a purely p-adic proof of the Weil conjectures has been completed using rigid cohomology (by Kiran Kedlaya, building on work of others).
Comment: "Dwork's difficult masterpiece  p-adic cycles" I wonder since some time if I should read that? A Zentralblatt review indicates that it may be outdated, an article by Katz on parts of it is described as unreadable. At this occasion an other question: Do you have a text of your talk: http://www.math.uchicago.edu/~emerton/AlgGeom/AlgGeomAbstracts/p-adic.html ?
Answer: I agree with Emerton's answer (and had similar thoughts, but since he is a leading expert in this field, it's better if the answer comes from him).  I would say that if anything the opposite is true: nowadays people (especially those of an arithmetic bent) are more interested in $p$-adic cohomology than $\ell$-adic cohomology and the former is viewed as richer and more difficult than the latter.  Thus the importance of Dwork's work could scarcely be higher.
Flipping to the other side of the Weil conjectures, I think it is also not quite fair to say that Deligne proved the Riemann hypothesis "with Grothendieck's methods".  I know you mean that he used Grothendieck's methods ($\ell$-adic cohomology) rather than Dwork's methods ($p$-adic analysis) but it doesn't do justice to the range of new ideas that Deligne brought to the table (as well as the ideas that were left on Grothendieck's table, to Grothendieck's eternal consternation).
Flipping back again, note that the Weil conjectures (and even parts of Deligne's significant generalization "Weil II") have since been proven completely by $p$-adic methods, c.f.:

Kedlaya, Kiran S.(1-MIT)
  Fourier transforms and $p$-adic `Weil II'. (English summary)
  Compos. Math. 142 (2006), no. 6, 1426--1450.
http://arxiv.org/abs/math/0210149

This is another sign that the "Dwork school" is going strong in contemporary research.
Answer: If you want to actually compute zeta functions of varieties over finite fields, then the p-adic methods are often more efficient. See e.g. the work of Kedlaya.
Comment: I'm upvoting this answer, because I think that the work of Kedlaya is most relevant to the question.  But I also think this answer should be expanded to include more history on Monsky-Washnitzer cohomology, etc..  My impression is that Kedlaya's work is strong enough to prove the Weil conjectures with purely p-adic methods, but I'm not expert enough to say who else contributed to this before Kedlaya.  Also, I do not know whether p-adic methods are strong enough to prove everything in Weil II.  Perhaps an expert can expand on this answer?
Comment: Kedlaya built on the foundational work of Berthelot and others, and was also very much inspired by Laumon's proof in the $\ell$-adic context via the Fourier transform.  Of course, Kedlaya added a lot himself, and here it is also worth mentioning that his underlying techniques (the $p$-adic analysis of Frobenius) are squarely in the tradition of Dwork.
Comment: @Marty: Good question.  In my answer (which was written independently of Felipe's answer and Bjorn's comment) I also mentioned Kedlaya's p-adic work.  But I implied that his methods give not only a p-adic proof of Weil conjectures but also "Weil II".  (This has since been fixed.)  Upon a closer look, it seems that he proves some but not all of p-adic Weil II.  I would indeed like to hear an expert weigh in on what remains to be done.
Comment: Would Satoh's algorithm for computing zeta functions, that relies on Dwork's work on deformations, be related to p-adic analysis? It's different than Kedlaya's work, but still uses p-adic geometry stuff that I don't understand.
Comment: Satoh's algorithm is indeed related although, for elliptic curves, the relevant p-adic theory was known before Dwork.


Extreme under extrusion Ender 3 Pro

Question: I'm having some severe under extrusion and I cannot figure out what's going on I replaced the extruder with the all metal one I've also replaced all the Bowen fittings and the tube with Capricorn tubing replaced the nozzle made sure everything was butted up tight can't figure out what's going on at all can someone please help I've only had the printer for 4 months and I've never had a problem like this before
Comment: Have you updated Cura? It sometimes resets the filament diameter to 2.85 mm, which will cause severe under-extrusion if you use 1,75 mm filament.
Comment: Actually believe it or not I did because I had to select generic filament because my filament was not on there and I selected pla and 1.75 mm I don't know what else it could be I would post a picture but I can't figure out how
Answer: I had a similar problem to you with my Ender-3 but now it is fine.
There are so many causes of under-extrusion that I doubt I can tell you what is specifically wrong in your case but perhaps I can give you some pointers.
In addition to what you have done, check if you can manually extrude the filament by releasing the grip on the filament (depress the lever on the feeder mechanism) and push the filament through with your hand (while the nozzle is heated to the correct temperature for your filament).
If that works well without too much force then it suggests one of two things:

an issue with the feeder mechanism (e.g. worn or clogged up teeth on cogs, spring too tight or too weak) or
extrusion settings on your slicer need modification (e.g. your slicer made G-code with too frequent retractions and this causes the filament to wear down thin preventing the extruder feeder cogs from gripping it. A solution is to reduce the maximum number of retractions possible by altering your slicer settings - this was an important factor for getting my machine to work again).
I found the following YouTube video helpful in giving me pointer of where to start - perhaps it will help you too:

Extreme under extrusion Ender 3 Pro


How can I update my jailbroken iPhone 3GS to iOS 6.1?

Question: How can I upgrade my iOS version to the latest version of iOS that I can have on my 3GS? I'm new to jailbreaking and to iPhones. I want to upgrade it to 6.1, but I really don't know how. My phone is already jailbroken.
Answer: Your best bet is to use iTunes to update it:
(WARNING: this will factory reset your phone. You will need to ensure all your data is appropriately backed up - you'll also have to re-jailbreak afterwards.)
Put the phone in recovery mode and plug it into the computer.
Next, open iTunes. It will tell you it has detected an iPhone in recovery mode and give you the option to update and restore it. Do this. (It will download about 700 MB of data and then factory reset the phone.)
Boot your phone up and it will be running iOS 6.1.6! You'll need to re-jailbreak.
An iOS 6.1.{3+} jailbreak needs a tool called p0sixspwn to be untethered - be sure not to forget that! (I won't go into detail here, but there is plenty of info online about this extremely simple step.)
Enjoy!


"Relative pronoun and Conjunction"

Question: What are the basic difference between Relative pronoun and conjunction
Answer: Hmm, those are two very different ideas.
A conjunction connects two sentences or clauses or items in a list together. Common conjunctions are "and", "or", and "but". Like, "We will go to the store and we will go to the park", or "He saw it but he still did not believe it." And the "or" between those two examples is another example.
A relative pronoun is a pronoun that introduces a clause that refers back to something mentioned previously in the sentence. "Bob, who is tall, hit is head on the door." "Who" is a relative pronoun that refers back to Bob. Relative pronouns are often words used to introduce questions, like who, when, and where.
I can't think of an example where a conjunction could be used as a relative pronoun or vice versa. If there are examples that just aren't coming to my mind, someone please shout one out.
Comment: @EdwinAshworth Sorry if my wording was unclear. What I meant to say was that some the same words used as interrogatives are also used as relative pronouns. No, when used as an interrogative, it is not a relative pronoun and vice versa. But the same words are used both ways. Like a word with two definitions.
Comment: I wouldn't call the question function of the wh-words a relative pronoun usage. The term 'interrogative pronoun' is often used here.

"Relative pronoun and Conjunction"


Mouse is too sensitive - disrupts sleep

Question: I have bought a gaming mouse with 8200dpi. However, when I use it in Linux I have a problem. When I do not use the PC or watch a video, mouse sometimes generates short moves in response to touching the table or even people walking in the room. Those responses end screensaver and cause video player GUI to show. This is annoying.
What can I do to counter it?
Comment: You could unplug the mouse when you're not using it...
Comment: If you're unable to set the mouse DPI (which apparently is not possible), the only solution is probably Jacob Vlijm's script or something similiar. However the quick and dirty hack I use for this is to turn the mouse upside down ;)
Comment: I've tried. I turn mouse upside down - it turns itself into proximity sensor :(
Comment: Sleep as in blank screen, or sleep as in whole computer?
Comment: As a blank screen. Actually, anything that is supposed to stop on mouse move. Mouse is so sensitive, it actually generates move events on slightest vibration. And by default, there is no "minimum travel" to disable screensaver.
Answer: A possible solution is the background script below.
What it does

After an (arbitrary) idle time, the script will disable the mouse, making it insensitive to whatever you do with it. I would set this relatively short, so there is little chance of disturbance in between.
A simple keystroke however (any) will enable the mouse again.

Since xprintidle is triggered by either mouse- or keyboard events (not by what happens on screen), the script will not be disturbed by e.g. playing a movie.
That way, you won't have to fear an unwanted mouse action will disrupt anything, while you still have easy access to the controls and your computer.
As always (and as it should be with background scripts) the script is written in such a way that consumes practically no resources.
The script
#!/usr/bin/env python3
import subprocess
import time
# ---
# set your device (mouse), as found from the command: xinput list
device = 8
# set the desired idle time (in seconds) to disable the mouse
set_idletime = 5
# ---

# don't change anything below
idle1 = 0

while True:
    time.sleep(1)
    idle2 = int(int(subprocess.check_output(["xprintidle"]).decode("utf-8").strip())/1000)
    if all([idle1 <= set_idletime, idle2 > set_idletime]):
        subprocess.Popen(["xinput", "set-prop", str(device), "Device Enabled", "0"])
    elif idle2 < idle1:
        subprocess.Popen(["xinput", "set-prop", str(device), "Device Enabled", "1"])
    idle1 = idle2

How to use

The script needs xprintidle:
sudo apt-get install xprintidle

Copy the script into an empty file, save it as mouse_toosensitive.py
Find out the device (number, integer) of your mouse by running in a terminal:
xinput list

In the head section of the script, set both the device number and the desired idle time (see explanation in the script).
Test- run it by running it from a terminal window with the command:
python3 /path/to/mouse_toosensitive.py

If all works fine, add it to your startup applications: Dash > Startup Applications > Add the command:
/bin/bash -c "sleep 15 && python3 /path/to/mouse_toosensitive.py"

Comment: Now that IS a universal idea. I like it.
Comment: @DmitryGrigoryev just tested with `VLC`,  the script, using `xprintidle`, happliy disables the mouse, meaning it is insensitive to what happens on screen :) (as I assumed).
Comment: @BarafuAlbino could you confirm if this solution works with your media player? My understanding is that most media players trick the X idle time to disable screensavers, which will also prevent this script from running.
Comment: Will try it at Thursday and then report right here. Anyway, I prefer SMplayer, and it has toggleable checkbox for screensaver prevention.
Comment: @DmitryGrigoryev `xprintidle`  listens to keyboard- and mouse activities, not to what happens on the screen.
Comment: @BarafuAlbino But if you uncheck the said checkbox, wouldn't this lead to a worse problem of your screensaver starting in the middle of a movie?
Comment: @JacobVlijm I'm not sure. The `man` page says: "`xprintidle` is a utility that queries the X server for the user's idle time and prints it to stdout (in milliseconds)".
Comment: @DmitryGrigoryev it worked in other situations similarly (but another question :)): http://askubuntu.com/questions/524384/how-can-i-keep-the-computer-awake-depending-on-activity/524847#524847 In my tests there, the *movie* didn't trigger `xprintidle`. The proof of the pudding is the eating however.
Comment: @JacobVlijm That's great news, your solution covers every need!
Comment: Has someone adapted this script, for **16.04** as a **systemd** service?
Answer: Of course I'm sure you have already experimented with the mouse controls such as:
xset mouse
$ xset mouse [speed] [threshold]

and
Find your input device number
$ xinput
$ xinput --set-prop 9 'Device Accel Constant Deceleration' 3

If experimenting with the available values there doesn't help, try changing your mouse pad to a surface that has more drag.  In other words experiment with different type of mouse pads for various sensitivities in that capacity.
Comment: `xset` defines speed, but the problem is - some cases react to any movement, no matter how small or slow.
Comment: I mentioned the speed and the threshold to make the range so wide to test the limites of `no matter how small`.  Did you test changing the mouse pad surface material to add more friction/drag.
Comment: I got an error: "property `'Device Accel Constant Deceleration'` doesn't exist, you need to specify its type and format"
Answer: If you're using xscreensaver, there's a configuration parameter that fits right in - pointerHysteresis:

If the mouse moves less than this-many pixels in a second, ignore it (do not consider that to be "activity.") This is so that the screen doesn't un-blank (or fail to blank) just because you bumped the desk. Default: 10 pixels.

Another solution I would try is to buy a nice silicone mousepad which may reduce the unwanted motion to a minimum.
Comment: Good for screensaver, but will require me to set up xscreensaver first. However, I really find video player problem much more annoying.
Comment: @BarafuAlbino Yes, this solution is only good for `xscreensaver` users, and I don't really expect anyone to change their screensaver to apply it. I for one wouldn't be able to use it myself, because my HDMI screen fails to go to standby when I use `xscreensaver`, so I'm stuck with `xautolock` instead.
Answer: Place an ink pen under the back of the mouse to lift the optical sensor above the distance where it will react to movement, remove ink pen when you want to use the mouse again.

Mouse is too sensitive - disrupts sleep


fast food is about more than just nutrition

Question: What is the structure? It is really hard to understand why they use the phrase "more than just".
Comment: This is a common structure meaning fast food is related to (is about) nutrition, but more that just that (perhaps presentation, price, and convenience).  They said it, I didn't.
Answer: It's not completely clear what you are asking but I think maybe you are confused with this because it's very common that people speak about fast food negatively with regard to nutritional value.
The sentence could easily be changed to:

fast food is about more than only nutrition

I'm guessing "just" is confusing you? Just is a way to say that something is not to the exclusion of other things. It can be replaced with only easily (usually). I can also say, "I just want to be friends". It has nothing to do with something being "just" in the sense that it's right or wrong or of noble value. It means, "I only want to be friends", in that particular context.
Just has a couple of meanings. It can mean something is noble or right. It can also mean that something is not to be singled out as the only thing. Or it can mean it IS the only thing.

I "just" want to be your friend.

means I "only" want to be your friend. But it does NOT mean I don't want any other friends or that I want you to have no other friends. Don't confuse those.

I'm not "just" your friend, I'm more than that too.

means I am more than a friend, I am more things than only a friend.
This is how the sentence is being used in your example. It's saying that for all the negative things we usually talk about regarding fast food, we need to consider more, because,

fast food is about more than "just" nutrition.
Answer: As for the the grammatical considerations, well, I'll leave those to the grammarians.
As for the meaning of the phrase "more than just," it is a shorthand way of saying, for example,

Regarding fast food, there are more considerations in play besides just nutrition. For example, there is . . .. [Fill in the ellipses with a list of other considerations or factors associated with fast food].

Using my imagination, I can think of several considerations regarding fast foods. Put negatively, they could include

the absence of joy in a home-cooked meal, enjoyed around a dining room table, with family and friends enjoying their repast and conversing freely about all sorts of thing

the cravings and habituation associated with many fast foods, including high salt content, high fat content, high sugar content, and instant gratification

the cost of fast food in comparison to the cost of a similar but home-cooked meal (in other words, economic considerations)

the sheer waste of resources, particularly the trash generated by consumers of fast food: paper, Styrofoam, condiment packaging, plastic, and more

the over-reliance on fast food, which obviates the need for experimenting with recipes for home-cooked meals

fast food encourages sloth with its convenience and speed, with very little effort involved (e.g. not having even to get out of a car to order, pay for, and consume the food)

On the positive side, fast food certainly provides employment for hundreds of thousands of workers and business owners and operators. There are probably many more positive aspects of the fast food industry, but from the tone of your exemplar sentence, the implication or connotation of the phrase "more than just nutrition" is that nutrition is not the only negative factor associated with the phenomenon of fast food. Hence the expression "more than just nutrition."


Geocoding Zip Code Issues

Question: I am geocoding addresses using the ArcGIS Online Geocoder and Street and Zip Code. In some cases, the geocoder has read the zip code as 4 digits and in other as 5. I got a 99% hit rate, but the addresses not are geocoded correctly as a result of this error. How do I fix this? Maybe add a field for city?
Answer: I think a better question would be why is it only reading 4 digits instead of 5?  But to answer your question,  ArcGIS Online will geocode fine without a zipcode if you have proper street naming, including a N,S,E,W prefix for streets that share an address, and you include the city and state.
Quoted from ESRI:
This operation can be used to find the following types of locations:
Valid Street addresses:
27488 Stanford Ave, Bowden, North Dakota
380 New York St, Redlands, CA 92373

Geocoding Zip Code Issues


how to calculate area verses each NDVI value?

Question: I created an NDVI map, I want to calculate area of vegetation verses the respective NDVI value of the given map. Which tools are used for this process and what steps are required?
Answer: If I have understood your question correctly you have created a raster which is an NDVI of your area of interest and you want to create a graph of area versus NDVI value, is this correct?
Your NDVI raster will be of type float and with therefore not have an attribute table. You could multiple this up by say 1000 to move the decimal place and convert to an integer grid. This will allow you to create a raster attribute table (number of pixels for each value). You could then copy that into your preferred graphing application and plot. You would need to convert the number of pixels to an area value first and divide your NDVI values to return them to their original value.


Is there a religious responsibility to study agadic material?

Question: Is the study of agadic material i.e stories which are not related to the practice or theory of Halakha, incumbent upon a Jew? In other words, is there something inherently wrong with not learning agadah as regards Torah study obligations?
Comment: Answers to [this question](https://judaism.stackexchange.com/q/69136/1739) answer this question.
Comment: Why would you think they are not part of the general obligation to study Torah? Are you asking what is the value of studying agada, and what we are meant to take from it?
Answer: The gemara (kiddushin 30a), when discussing a father's obligation to teach one's son Torah, says: (free translation)
"How far does the obligation to teach one's son Torah go? Rav Yehuda said in the name of Shmuel: like Zevulun ben Dan, whose grandfather taught him Mikra Mishna Talmud Halachos and Agados."
The gemara then discusses this further. But the whole discussion just revolves around how much is the father's (and grandfather's) obligation to teach the son, versus what the son himself needs to study.
This is quoted I believe in the Shulchan Aruv Harav (I don't have access to one right now to check, but I believe he poskens this.)
There is also the medrash on Mishlei- I think it's Yalkut Shimoni, perek 10- that says that each person will be asked in heaven if they studied mikrah, Mishnah, Talmud, agadah, and even more things like maaseh Merkava etc. If the answer is no, and the explanation is not acceptable, a person will be taken to task. (It's worth trying to see the actual text since it's very powerful. I'll try to find it later.)
You can also look in R' Dr. Yehuda Levi's work "Torah Study" where he has a whole chapter devoted to how the study of agadah is necessary to properly fulfill many obligations. i.e. mitzvos of bitachon, emunah, Simcha etc. can only really be understood well through study of agadah.


What kind of technologies are required for a society to regularly produce jet engines?

Question: Specifically, I'm looking for what areas of science would need to have been developed for the manufacturing process of jet engines to be commonplace for large manufacturing firms.
For context, my world is relatively low-tech with scattered points of industrialization ("high-tech"). What kind of industrialization is wholly determined by what levels are needed for jet engine (turbofan, turbojet, air breathing combustion engines, etc.) manufacture.
Knowing this small detail will greatly help me further my worldbuilding process.
Comment: Look at our own history. The idea of a gas turbine was patented in *1791*, and a running gas turbine was built in *1906*. Researching the history of gas turbine engines will answer your question. http://web.mit.edu/aeroastro/labs/gtl/early_GT_history.html
Comment: My own world, while not quite the same, has enough in common. I will definitely be keeping an eye on this one.
Comment: Have you considered the other setting elements necessary for jet engines to be useful, not just technically feasible? Jet engines came into common use as a result of their better performance at high speeds and high altitudes. Even today, low-altitude, lightweight, and short-ranged aircraft typically remain piston-driven.
Comment: Can you share to what extent you've researched early jet engines, as for instance Nazi during and British immediately after World War II?

Beyond the science and technology several documentaries on TV, never mind on-line channels, examine in great detail the resources and logistics involved in war production.

That many conclude the Nazi's might well have won if only they'd know what they were doing is a deeply sobering thought!
Answer: The history of the steam turbine is 2000 years old if you consider Heron's Aeolipile.
https://en.wikipedia.org/wiki/Aeolipile
What is needed for turbine engines in the modern sense?
Metallurgy: to make the engines more powerful, the components need to withstand high heat and stress.
Gears: turbine engines want to spin really fast, too fast to directly connect to a propeller.
Machine technology:  turbine components and gears need a high level of manufacturing precision.
Fuel: for an air breathing turbine you'll need a liquid fuel like kerosene.
So what level of human history was this possible?  The modern steam turbine was patented in 1894.  The Germans and the British had air breathing turbine engines for airplanes in 1937.
https://en.wikipedia.org/wiki/Turbinia
Comment: This is a good answer. It has components I was hoping to get from an answer to such a question; the things I had not thought of. High heat and stress, gears, and machine crafting technology have a logical bondage with one another, where a factor of one motivates a factor in all. Yes, good answer.
Answer: If you are looking for very simple yet useful(so no Aeolipile) jet engine then look into valveless pulsejets. They are quite noisy, have short lifespan and are quite inefficient(about 700 s against 3000 s for good turbofan) but are extreamly easy to make - you can make one in garage(or this site) like conditions if you have some Bessemer steel sheets and welding, maybe you can make one just by forging wrought iron by hand(nobody tried this one but I think it could work).
They can work on anything that works(even coal dust has been tried).  Common misconception about pulsejets is that they do not work at rest - they do, but take-off just on pulsejet would be very inefficient.
For further details I would highly recommend «The enthusiast guide to pulsejet engines» by Simpson Bruce.
Answer: Looking at jet engines there were actually a multitude of inventions that needed to occur to overcome:

Weight penalty
Fuel consumption
Safety
Reliability
Sustained operation

Propeller driven engines were well-known throughout the pre-WW1 period, but their limitations were well known, in terms of power and therefore altitude and speed. Ironically, prior to and in the early portion of WW2, the above issues were solved by both german and allied researchers such that the first stable jet engines were able to go into production just prior to the end of the war.
However, these early models during the war were still experimenting with turbofans, with new forms of liquid fuel and new metallurgical techniques. Safety was a major issue, with failures in jet engines quite common. Also at this time they had very limited range.
It would take decades to refine all of the above to give confidence to not just militaries, but to also commercial operators, to allow mass production.
Keep in mind the engine is only one part of the equation necessary for flight. For instance in the Korean War, it was discovered that the US jets were being shot down a lot of the time due to them not having swept wings, where their MIG counterparts did (for serendipitous reasons). Fuel and range was a major issue too until more efficient Bypass turbofans were invented and studies in aerodynamics were perfected. Metal stress and fatigue for multiple flights (even things such as the dangerous discovery regarding square windows) evolved the form of aircraft, and even maintenance - this is why you see a lot of pod engines mounted underwing now, as you can access them to maintain them whereas tri-jets and rear pods were harder to maintain because they were higher up.
Commercial air-craft design is fascinating - they evolve through thousands of small improvements over time to form what they are now.
Answer: A pulsejet can be made with very limited tech.
Really: bronze working, and alcohol distillation would suffice for a minimum working model. Just see how easily Colin Furze bashes one out!
But you are interested in jet turbines, right? The rotating sort?
Your primary requirement are Metallurgy and accurate Machining for the turbine blades, and ditto for the bearings.
You need to be able to make a turbine blade that is shaped very exactly, that can withstand high RPM spinning while subjected to temperatures of at least 850C, preferably up to 1400C+. And this temperature is imparted by combustion occurring directly next to the turbine blades.
All of the force of this turning turbine needs to be rotated around an axle, which of course means bearings. Bearings that can take significant temperatures and vibration.
And both the Turbine blades and the Bearings must not fail, ever.
A failed bearing or turbine blade in a turbofan engine is a catastrophic failure, at minimum stopping the engine and likely destroying it. Possibly taking its airplane with it.
It would be handy to have a gearbox, but this is not strictly needed to make a functional turbojet. It does improve efficiency though. But if you can make the turbine blades, a gearbox should be easy enough.
To keep the jet engine running, you need a supply of fuel that is energetic, very pure and predictable. Thus a petrochemical industry and everything that goes with that. But the requirement is less advanced than that for metallurgy.
There are a lot of other tech that are needed, but at much reduced levels. Electric controls and sensors, sheet metal work, machining of accurate shafts, etc.
But if you are capable of making metal turbine blades, you are more than capable of the simpler metalwork in the rest of the engine. And the rest of the airplane, for that matter. The turbojet is by far the most technologically demanding part of a jet aircraft, and the turbine blades are by far the most demanding aspect of the engine.


Data on Medicare Advantage Plans

Question: I'm looking for data on Medicare Advantage Plans: eligibility, cost, coverage, etc. Where can I find it/
Comment: In addition to [medicare.gov](https://www.medicare.gov/plan-compare/#/?lang=en), a quick Google search shows many sites that let you search for plans by zip code.  What is the geographic and temporal scope you need?  Are you looking for a single database that combines all potential plans given a consumer's characteristics?
Answer: The plan finder on Medicare.gov has some of the information you seek.  It is only a general overview, however.  It is missing some of the specifics, such as costs for certain types of medical care.  I have used it to help some people in the USA find appropriate coverage.  When doing so, I did find some of the information to be inaccurate.  I also found that sometimes wide ranges of costs were presented for some medical care/treatments/procedures, which was not helpful.  For example, I once saw something like $0-$800 specified for a plan's medical imaging copay.
The following website has data on estimated costs, by region in the USA, based on approximate anticipated health status: http://www.medicarenewswatch.com/index.php/en/cost-comparisons
Here is the FAQ explaining the data presented on that website: http://www.medicarenewswatch.com/index.php/en/faq
I am currently unaware of any data source that contains comprehensive, accurate, and detailed Medicare Advantage Plan information.  If someone is aware of such a data source, I encourage them to add another answer.

Data on Medicare Advantage Plans


Checklist for Technical Critique

Question: Is there a checklist that covers the basic technical aspects of a photograph? I assume reviewers for micro stock websites go through a set list of points and professionals have some mental checklist they go through. Can anyone elaborate on this?
Comment: Possible duplicate of [Is there a set of common criteria for evaluation of photographs?](https://photo.stackexchange.com/questions/30814/is-there-a-set-of-common-criteria-for-evaluation-of-photographs)
Comment: Do you mean specifically for microstock? I think this is too broad and subjective otherwise. (Or — there may be a checklist for photography in general, but it'd have a lot of "or, whatever" clauses.)
Answer: I think the Professional Photographers of America (PPA) criteria sums it all up. I was a member for many years. Follow this link.
Professional Photographers of America – 12 elements to judge
1.) Impact.
2.) Technical
3.) Creativity
4.) Style
5.) Composition
6.) Presentation
7.) Color Balance
8.) Center of Interest
9.) Lighting
10.) Subject Matter
11.) Technique
12.) Story Telling
Link below is good reading!
http://www.ppa.com/competitions/content.cfm?ItemNumber=1792
Comment: As you should be aware by now, Stack Exchange heavily discourages link-only answers. Please summarise the content directly in your answer.
Answer: I don't think there's a single checklist. I've spent a little time looking at the forums of some stock photography web sites and can list at least a few of the technical things they look for:

Focus - are the right things sharp? Are the sharp things sharp enough? Is the depth of field appropriate for the subject?
Composition - this one is a huge topic and may not be considered technical, but in general, is the composition balanced? (Or appropriately unbalanced if that's the point?) If you intended to follow the rule of thirds or use the golden ratio, did it actually work out? Is the framing right? Is the subject properly isolated?
Chromatic Aberration - is the CA minimized or at least not objectionable?
Vignetting - is the vignetting either not there, minimal, or appropriate for the image?
Exposure - Is the exposure good?
Illumination/Lighting - Are the right things illuminated properly and effectively? Are the wrong things deemphasized through illumination? Have you used the right types of lighting for the subject? Have you placed the lights right, or placed the subject in the light effectively?
Color - Does the color work for the subject? Is the color accurately reproduced?
Perspective - is it right? Does it make anything too big or too small relative to other things in the image?
Lines - Do the lines in the image draw the eye to the appropriate places? Or do they conflict with the subject or draw the eye away from where it should be?
Motion Blur - this goes along with focus, but is more about shutter speed than lens focus. Have you either removed unwanted motion from the frame or emphasized desired motion appropriately?
Shape - have you captured the shape of your subject accurately?

I'm sure there are more, but those are the first ones that I think of when thinking about this subject.
There are also those that relate more to delivery of the photo than the actual photo:

Is the resolution high enough?
Is it in the right format? (JPEG, TIFF, RAW, etc.)
Is the aspect ratio the right one for the delivery medium (16:9 for stuff that will go into HD video, for example)
Answer: Wikipedia Commons has a decent set of standards along with examples and an ongoing Quality Images submission page where active application and feedback based upon their standards are available to observe daily. Their guidelines encompass the same line items mentioned in other answers here, but I'll repeat them here for reference. Note that the primary display medium for Wikipedia/Wikimedia is a web browser- additional standards also apply for images destined for print.
Paraphrased from Wikimedia Image Guidelines:

Resolution: Avoid downsampling, images should contain adequate detail
Compression: Images should not be stored in a format with excessive compression.
Noise: Images should not have excessive noise when viewed in original size
Exposure: Avoid overexposure, blown highlights, underexposure, lost shadow detail
Color: Images should have reasonable colors, be properly white-balanced, low chromatic aberration, samples should be in a proper color space
Focus / Depth of Field: Key objects in the image should be sharp, and the overall image should have clearly defined focus
Motion Blur: If present, it should have a purpose (quote: to emphasize motion)
Lighting: Lighting should be appropriate for the given subject; avoid distracting reflections, inappropriate vignetting, harsh shadows, lens flare
Editing: Avoid unnecessary use of artistic filters and effects. However: cropping, perspective correction, sharpening/blurring, color correction, etc can be beneficial.
Composition: The arrangement of image elements should support the subject, not distract from it. Foreground/background objects should not be distracting.
Distortion: Images should not be unintentionally tilted, architecture should be rectilinear, perspective distortion should either contribute to the image or be insignificant, avoid or correct barrel/pincushion distortion.

Here are additional items quoted on that page but not enumerated:

Stitched Images / Panoramas: Avoid stitching artifacts, ensure color/luminance/lighting is consistent across the image, correct parallax, avoid vignetting.
Color Spaces: This is specific to display on Wikipedia / Wikimedia and  websites in general, but images should generally be in sRGB color space or include a proper ICC profile.

Checklist for Technical Critique


A request to the boss

Question: When I have something  I want to ask my boss, is it appropriate to say it like this?

• I have a request to you. Would you please ...?

Is there any more appropriate or polite way to say that?
Answer: The first sentence should say "request for you", not "to you".
If you want to make it sound more polite, you might add more words and a note of hesitancy. For example,
"Excuse me, [boss|Ms. X|Mr. Y], but I wonder if you could do something for me. My request is...".

A request to the boss