How far can the Sun and the Moon get?

Question: I noticed that last June the Sun was on the tropic of Cancer and moon on Madagascar:

Can you explain how that works and if they can get even farther in latitude?
Answer: The Earth's equator is inclined to the plane of the solar system (called the ecliptic) by 23 degrees. In other words, the Sun's position, as seen from the Earth, varies between 23 degrees North (at the northern hemisphere summer solstice) and 23 degrees South (at northern hemisphere winter solstice), appearing to cross the Earth's equator twice (at the equinoxes).
The tropic lines mark the maximum apparent solar move north or south.
The Moon's orbit is inclined by about 5 degrees to the ecliptic so moves over a somewhat wider range of the sky as seen from the Earth. The Moon orbits the Earth every 28 days or so, so moves over that range each month.
At full Moon the Moon is opposite the Sun in the sky, so if the Sun was close to the tropic, then the Moon would be around the opposite tropic when full, and so on.
Comment: No, it's more like 52 degrees, but that would be very rare: this may help explain some more https://en.wikipedia.org/wiki/Lunar_standstill
Answer: You mean the point on the Earth where the sun and moon are directly overhead?   Just as eclipses can happen, being on opposite sides of the Earth can happen too.   Generally speaking this is a lunar eclipse.  Directly opposite, just like solar eclipses are relatively uncommon because the moon orbits the Earth on a different plane than the Earth's orbit around the sun, so the timing has to be just right for them to line up.  (see somewhat exaggerated diagram).

For example, if you were to carefully draw the equator across the picture you posted, you'd see the Moon and Sun are not at opposite latitudes, which they would need to be to be as "far apart as possible".

How far can the Sun and the Moon get?


Stop update the Arp table

Question: I have a trouble in my network. Somebody in our network runs a sniffer. He gets all data packets. Actually he is a friend of mine. So what I want do is to only stop update my ARP table. like When he is sniffing, all the ARP tables of all machines always update. Does anybody know to stop this?
Thank you.
Answer: Actually this is the "ARP Vulnerability" problem. The person in your network uses the mechanism on MITM (Man in the Middle) attack to create a route so that the packets that u receive/send is intercepted by him, thus enabling it to sniff your packets. As far as I know this vulnerability has not been resolved because the ARP protocol is "trusting" , which means it does not validate ip-mac pair. Only way to stop is get him off the LAN :)
Answer: I don't quite understand your question. When he's sniffing, there should be no change on the ARP table of your machine.
Is he sniffing (reading packets as they go through the network), or is he scanning (sending probes and/or strange packets to other machines)?

Stop update the Arp table


How often can a Google form receive responses?

Question: I am designing a test using Google Form. It has a time limit, after which the form will not accept responses. I am concerning that at the very last second, there will be 20 responses submit and Google Form might have a problem collecting all of those. Is there a document anywhere state the capability of Google Form accepting responses?
The capability is something like data size over time or amount of responses in a period of time, not maximum storage ability or Google Sheet linkage.
Comment: Please edit your question to clarify what are you asking as well to include a brief description of your search / research efforts as is suggested in [ask]
Answer: Google has no published a any limit regarding the number of responses that can be received by a Google Form but there are reports of people getting problems with form response submissions some of the most common problems are related to forms sending responses to a spreadsheet and/or using on form submit triggers.
Comment: I guess sometimes the answer is there is no answer. I struggled a bit with the setup of submit trigger as well.


Through and through

Question: This word means the complete degree of penetration and you seem to double the "through" to make it sound stronger. I wonder, in Russian you say "along and across" to mean that you know something "inside and out", you know something very well, deep into the subject/matter. I wonder, have you the same meaning in English, the first "through" means "throughout vertically" and "throughout horizontally", resulting "through and through" -- both directions. I know the subject throughout, no matter which side we are looking at it. This is how I look at this phrase. Am I right or there is another origin?
Answer: The way it means in every direction is in uses like

"He's through and through an evil man"

or

"It was filled through and through with chocolate cream."

It means completely. I think his basic concept is a good one since through by itself is a one-dimensional thing. It's usually directional. Through and through tends to indicate two or three dimensions. If a boar was stabbed through and through with spears, it would indicate many of them.
Answer: I think you are taking it too literally.  Whether you mean it literally or metaphorically, it just means "completely through", not "through in both directions".  For example,

...(the boar was) struck through and through with two heavy lances...

I don't think that means the boar was literally run through both along and across, or vertically and horizontally.

To amuse himself till his lordship was at leisure, he took down a volume of Shakspeare splendidly bound, and on opening it discovered, from the gilding, that it had never been read ; also, that the worms were eating it through and through. Some dozen years afterwards, another visitor took down the same volume, and found the following lines pencilled by Burns on the first page : —
  " Through and through the inspired leaves
  Ye maggots make your windings ;
  ... (Source)

Again, that seems to mean "completely or repeatedly through", not "through in both directions".
Comment: I consider "etymology" as something that was taken literally originally but got different meaning later. So, I see no problem here and no difference between "completely through", and "through in both directions". You start with second meaning. It means/implies the first. You start to use it to express the first.
Comment: Well, I can't say for sure how it was originally used, but it is currently used in ways like "[through and through gunshot wound](https://www.ncbi.nlm.nih.gov/pubmed/16258297)" meaning *one* bullet going in *one* direction that went completely through, so I haven't seen any evidence that it means or ever meant "in both directions".
Answer: I would say the equivalent English phrase is "backwards and forwards."
We also like to say "I know something like the back of my hand."
I've also been wondering about this phrase "through and through" and finding a disappointing lack of info on its history. The only mention of original use I found was to mean a sword piercing armor and flesh - I'm guessing "through the armor and through the flesh" got shortened to "through and through," which became a figurative phrase meaning "thoroughly" in any sense.

Through and through


Computer failure diagnosis?

Question: I found this on my search for help for my (hopefully only temporarily) dead computer, and it seemed so useful that I thought I would try and ask for your help in reviving my computer - please?
It started failing last week - running fine but suddenly black screen and spontaneous rebooting which did not work. After shutting it down and switching back on, everything looked ok until, again, it suddenly died. Did this a few times, usually after 5-10 minutes it either froze or went to black and reboot.
I was trying to get my data off it with Synchback, and the profiles did not all run successfully (and gave a message about sectors and accessing), so people suggested that the hard drive might be failing. So I got a new one and put that in, but can't seem to get anything at all running - no Windows setup, no partitioning program, no clonezilla for hard disk restoring purposes. They all crash.
The hard drive, connected to my laptop, looks absolutely ok. Memtest reports everything ok with the memory. I can access the BIOS without problems.
I did replace the CPU fan last week just a couple of days before the first crash, but it looks to be running ok - computer reports a CPU temperature of anywhere between 29 and 50 degreed celsius at startup, depending on how long it has been running, obviously.
Any suggestions what it might be that causes this? People now suggest the motherboard may be failing, but if you can access the BIOS all right...?
I'd be grateful for any suggestions!
Comment: How old is the PC? Store bought or home built?
Answer: well you can try changing the RAM(if you have 2 sticks then remove one, try it, also try it with the other one), and you say you've tried changing the CPU.
you may isolate it to one of those parts, but if after all those troubleshooting steps it still fails, then it's likely the motherboard.
It's extremely common that a motherboard has issues and you can still access the BIOS. That's a norm.
As to the hard drive, you can put it in another machine / -one that works- and copy the data off it. If you think it won't fit there are lots of adaptors..  IDE/ATA to SATA,  2.5"(a laptop size hard drive) to 3.5" a desktop sized one. USB-SATA USB-IDE etc.
Really your problem is a simple fundamental one of troubleshooting to isolate the problem.

Computer failure diagnosis?


Time-dependent wavefunction numerical simulator

Question: I want to develop a visual simulation of a propagating 2D wavefunction with an added attractive potential. Basically I have to numerically solve the time-dependent Schrodinger equation (PDE with x,y,t as variables) but, instead of boundary conditions, I want to have an incoming wavefunction of my choice as the initial wavefunction profile. What software would give me a good environment for such a project (I'm thinking Mathematica, Comsol, Matlab as a starting point)?
Answer: You could start from the step-23 or step-25 tutorial programs of deal.II, see for example http://www.dealii.org/7.2.0/doxygen/deal.II/step_23.html . (Disclaimer: I'm one of the authors of this library.)
Comment: I ended up doing a classic Crank-Nicolson model in Mathematica for now (I'm personally more used to the language) but I'll definitely keep your suggestion in mind for a future more advanced approach. Thank you!


Tankless Water Heater and turning off main water supply

Question: I presume there must be plenty of protections for such a case, but is there any reason to be concerned if I turn off (or my fortrezz value and smartthings turns off) my main water supply and my Rinnai tankless isn't turned off?  I looked at the instruction manual and it doesn't mention any thing about this situation that I saw.
Answer: There are flow sensors in tankless units so if you are simply shutting down the valve on the water supply and then reopening it I wouldn't be too concerned. That being said shutting down the water supply can change the pressure in the system as temperatures of the water change. I don't think it would cause any trouble. But, anytime you close the valve the water is in a closed system. It's a good idea to install a potable water expansion tank.
This is a potable water expansion tank

www.amazon.ca
They are almost exclusively 3/4" NPT. You would need to measure your static pressure(pressure with the taps closed and the main open) with a gauge. Then pump air into the air nipple (bottom of the tank pictured above) with a bicycle pump or preferably air compressor to match the static pressure before installing it. It's a good idea to install a service valve as well.
Comment: Also in tankless system expansion tank is not needed because water is cold and heated only when there's flow, so there's no thermal expansionin 'no-flow' situation.
Comment: Some have flow and some have differential pressure switches. But both are doing the same thing,,, no water use no heat.
Comment: I've never run in to one on the water side. They must be fairly reliable. I use Navien exclusively. They use a flow transducer/hall effect sensor. I've changed a couple. But I've installed hundreds of units. I still have a faulty sensor in the garage. I connect to a 5vdc power supply and an LED while blowing in it and it knocks my kids socks off watching the light blink. Is it a variable pressure transducer? Or just a switch with the gas throttled via another sensor?
Comment: It can be both, on some system is used as variable transducer, in others is just on/off, usually the case is the second and the flame is adjusted by a temperature sensor: if it uses only the flow to determine the heat needed boilers won't be able to guarantee output temperature. So if acquaduct is 5° and boiler is set to 60° you may have 55°, while on 20° acquaduct you may have 75° DHW because tempes are calibrated with 10°C inlet. Usually old, mechanical only, instant-boilers have this kind of control wile newer with 'electronic control' use temperature and on/off flow-switch.
Answer: Tankless/combi just won't start if there's not enough flow (it's well written on tech label), usually minimum flow that let fire light is around 2L/min, that's intrinsic in their way of work.
Most use a microswitch to sense the flow and a temp. sensor to adjust the flame, other just measure the flow and adjust the flame according to that. Some have minimum pressure sensor, other do not but on DHW it's not needed.


Is there any way to run MS OUTLOOK 2007 on LINUX?

Question: I currently have Microsoft Business Productivity Online Suite (BPOS). It runs well with Microsoft Products like OUTLOOK (WIN) and ENTOURAGE (MAC). Unfortunately, my Linux users are struggling to run Microsoft Exchange on both Thunderbird and Evolution E-mail Clients. Is there any way to run MS OUTLOOK 2007 on LINUX? CodeWeaver CrossOver seemed to not have worked for me. May I be doing something wrong?
Comment: why does Evolution not work?
Answer: Run a Windows instance in a VMware or VirtualBox installation.
This sort of defeats the purpose of running Linux in some ways, but it works.
Answer: Wine is usually the best bet, however even that seems not to work -
Outlook 2003 - http://appdb.winehq.org/appview.php?iVersionId=2526
Outlook 2007 - http://appdb.winehq.org/objectManager.php?sClass=version&iId=7533
I guess that there is something in it that just does not want to work on Linux!
I looked at some other methods (including the ones you listed) but it just does not seem to want to work.
Whilst it is a annoying work around, your best bet will most likely be to use virtualisation and run outlook that way. Alternatively, as you state Exchange you most likely have a server infrastructure. If there are not too many users, you may want to try installing outlook on the server and using it as a terminal server.
Again - these are just work arounds, and probably annoying at that, but they should do the job.
Sorry I cannot be more helpful, but from my research for you, it just does not seem as if Outlook wants to run on Linux.
Instead, what you may want to do is post your problems using Thunderbird or Evolution as there may be someone that can help you.
Answer: CrossoverOffice will run Outlook


Is it possible to combine multiple mods for Diablo 2?

Question: I'm considering revisiting D2 and I loved playing the Eastern Sun mod for no other reason than it took me away from the vanilla experience. I've since found several other mods and was curious if I could combine them together, and if so, how I could go about doing that?
Answer: It depends on how the mod files are structured. Most of the time with D2, you replace the patch file, and that replaces patch 1.13 with whatever mod you have.
If both mods function like this, it would be impossible to install both mods at the same time.
There currently is no Diablo 2 installer that allows for multiple instances of the patch file to run together.


Chern insulator vs topological insulator

Question: What is the basic distinction between a Chern Insulator and a Topological Insulator? Right now I know that a Chern Insulator has "topologically non-trivial band structure" and that a Topological Insulator has "symmetry protected surface states".
Comment: Chern insulators must break time-reversal symmetry and topological insulators require time-reversal symmetry for protection. Both of them have nontrivial band structures and edge/surface states, the difference being that TI is nontrivial only with time-reversal symmetry (and the edge states are protected by the symmetry).
Answer: I don't think the provided comment gives the right answer. Topological insulators is the bigger group and Chern insulator are a subgroup of that. This means that every Chern insulator is a topological insulator, but not every topological insulator is a Chern insulator. Can maybe someone confirm that this is indeed true?
In general a topological insulator is a material that has gapped bulk, but conducting edge states that are protected by some symmetry. The surface Hamiltonian is gapless and cannot be gapped by perturbations that do not break the symmetry that protects the edge states, people say that the edge states are topologically protected.
A Chern insulator is 2-dimensional insulator with broken time-reversal symmetry. (If you have for example a 2-dimensional insulator with time-reversal symmetry it can exhibit a Quantum Spin Hall phase). The topological invariant of such a system is called the Chern number and this gives the number of edge states. So, when you have a non-trivial Chern insulator this means that it has edge states. The edge states of a Chern insulator are chiral meaning that in one channel the electrons only go one way and in the other channel the electrons go the other way. This may remind you of the Integer Quantum Hall Effect, which also has chiral edge states. You can see a Chern insulator as a 2D lattice version of the IQHE. (It is also called the Quantum Anomalous Hall Effect). You can go from the trivial phase to the topological phase by changing parameters in the lattice model such as the on-site or hopping energy.
The first Chern insulator was the Haldane model for graphene, where time-reversal symmetry is broken by introducing complex second nearest neighbour hopping but inversion symmetry still survives. This gave the chiral edge states characteristic of the now called Chern insulators.
Comment: When you say "every Chern insulator is a topological insulator", you need to define what is "topological insulator". According to a standard definition, "topological insulator" is an fermionic insulator with time reversal symmetry and U(1) symmetry. According to this definition, a Chern insulator is NOT a topological insulator.
Comment: @Marnix Also, subgroup and subset are different words with very different meanings.
Answer:
2+1d Chern insulator (CI):

belongs to the classes of systems realizing Integer Quantum Hall states on the lattice without external magnetic field. It belongs to the long-ranged entangled Topological Order by the definition of X.G.Wen of MIT, but it is still a part of theory of Invertible Topological Quantum Field Theory (of Dan Freed, see References and papers by him) with its partition function $|Z|=1$ on a closed manifold, and can be gapped by coupling to its time-reversal partner (with opposite sign of the Chern number). It is however short-ranged entangled by the definition of A Kitaev of Caltech.

The Chern insulator on the lattice without external magnetic field realizes so-called the Anomalous Quantum Hall Effect.

And CI is characterized by the Chern number $C_1$ under the $\mathbb{Z}$ class of topological invariances:
$$
C_1=\frac{1}{2\pi}\int_{\mathbf{k} \in \text{BZ}} d^2\mathbf{k}\;  \epsilon^{\mu \nu } \partial_{k_\mu} \langle \psi(\mathbf{k}) | -i \partial_{k_\nu} |  \psi(\mathbf{k}) \rangle \in \mathbb{Z}.
$$

2+1d and 3+1d Topological insulator (TI):

belongs to the classes of systems realizing Symmetric-protected topological states, needed to be protected by time reversal and U(1) charge symmetry. The TI has NO bulk intrinsic topological orders.

The 2+1d and 3+1d free (quadratic Hamiltonian) TI both are characterized by the $\mathbb{Z}_2$ invariance instead of $\mathbb{Z}$ invariance. See the paper of Fu and Kane. The  can also be characterized by the $\Theta=\pi$ for the probed bulk U(1) field action (see Qi, Hughes, Zhang, Phys Rev B 2008.)
$$S_{3+1d\;bulk}= \frac{\Theta}{8 \pi^2} \int F \wedge F$$ term with some proper normalization.
Namely the 3+1d $\mathbb{Z}_2$ for free TI is
$$
\Theta=0, \pi, \mod 2 \pi
$$
which generates the $\mathbb{Z}_2$ class (of TI). Both
respect the time reversal symmetry.
Comment: Some of the others' most up-voted answers are obviously wrong. Not sure how people judge the answer...
Answer: A topological insulator has a non-trivial (non-zero) topological invariant.
Chern number is one such topological invariant. If the Chern number is non-zero, then the system is a Chern insulator. Hence, a Chern insulator is a subgroup of topological insulators.
Answer: you cannot discuss classification of topology without symmetry.
Any gapped system with nontrival edge states can be called as topology insulator. Haldane model defined in honeycomb lattice is an example of chern insulator which has non-zero chern-number and doesn't need any symmetry to protect it from adiabatic transform (without gap close) to a trival insulator.
Z2 topology insulator is a subset of chern insulator but its chern-number  is zero. However, it still has nontrival edge mode which need to be described by a new topology index called Z2 index. The reason why it belong to the subset of chern insulator is that it need time reversal symmetry to protect it from adiabatic connected to an phase which has different Z2 number.


SP 2010 Outlook calendar sync: What is this specific setting?

Question: This is a calendar I created in SharePoint and I want users to sync it to their local Outlook clients. When you initially connect the calendar to Outlook there is a dialog that comes up with a "yes" or "advanced settings" - the image is showing the advanced settings. I am specifically interested in the one I circled in red in the screenshot. I can't find any documentation out there on this, and it seems like this is a setting i would NOT want to have checked... but why would it be checked by default and hidden in advanced settings?  So maybe I don't have a good understanding of the setting. Anyone able to enlighten me on this?
Answer: With that setting checked, the SharePoint calendar that you connect to Outlook, will appear in your Outlook when you log into another computer.  This is preferred.
If you uncheck this option, and you go to another computer, that calendar will not appear in Outlook.


Detect compiler used for EXE file

Question: Is there any way to detect (or to hide) the compiler that was used to build an executable file?
Answer: Try the *nix utility strings.  Using strings -a foo.exe  should produce a pile of results.  Redirect to a file and examine in your favorite editor.  You may see either a line that directly implicates a specific compiler, such as Borland C++ - Copyright 2002 Borland Corporation.  You might only be able to find lines that imply a specific compiler was used, such as in an include path or whatever.
Strings is also available for windows as part of cygwin, or as part of the microsoft sysinternals package.
Comment: It doesn't show me the compiler name only some dll names project
Answer: PEiD is pretty good

PEiD detects most common packers,
cryptors and compilers for PE files.
It can currently detect more than 600
different signatures in PE files.
PEiD is special in some aspects when
compared to other identifiers already
out there!

It has a superb GUI and the interface is really intuitive and
simple.
Detection rates are amongst the best given by any other identifier.
Special scanning modes for advanced detections of modified and unknown files.
Shell integration, Command line support, Always on top and Drag'n'Drop
capabilities.
Multiple file and directory scanning with recursion.
Task viewer and controller.
Plugin Interface with plugins like Generic OEP Finder and Krypto
ANALyzer.
Extra scanning techniques used for even better detections.
Heuristic Scanning options.
New PE details, Imports, Exports and TLS viewers
New built in quick disassembler.
New built in hex viewer.
External signature interface which can be updated by the user.
Comment: "PEiD detects most common [...] compilers for PE files." that's what the readme says - actually it does not tell how to achive that
Comment: "The site ahead contains harmful programs" - Google Chrome. [Here's a better link.](http://www.softpedia.com/get/Programming/Packers-Crypters-Protectors/PEiD-updated.shtml)
Comment: @Sathya Note, the included link is now dead.
Comment: @DuckMaestro updated witi an alternative link
Comment: If it cannot detect the compiler something like _Nothing found [Overlay] *_ will be shown - which is confusing if you use that tool for the first time.
Answer: When this question was asked, PEiD was only a couple of years out of date.
These days, you're probably better off using Detect It Easy: https://github.com/horsicq/DIE-engine/releases or https://horsicq.github.io/#detect-it-easydie
Answer: (Old but okay..)
Language 2000 : http://farrokhi.net/language
Answer: Not free, but IDA Pro has a very nice compiler detection. Not it's main function of course, but a nice extra.
Answer: If you can find a way to examine the first dozen or so bytes of the EXE file, in a hex dump with corresponding ASCII characters displayed, they will usually indicate the compiler used.
Comment: i was wondering if someone or some software can find if the exe was build with a specific compiler edition (Visual Studio 2010  Professional or Enterprise or Express)
Comment: This usually isn't true. The first part of a PE file is the DOS stub which is usually a program that prints something like "This program cannot be run in DOS mode."
Answer: You can use "dependency walker" to check what runtime library it links to. MSVCP100 is Microsoft Visual C++ 2010 x86
Comment: linking to MSVC runtime doesn't mean that it's been compiled by MSVC

Detect compiler used for EXE file


Estimating volatility from high frequency price volume data of multiple stocks

Question: I have price volume data of five stocks, sampled at 1 minute interval for six months. The data is quite noisy, lots of missing data and also some weired spikes. Can someone suggest me how to clean this dataset? The main objective is to estimate the volatility for the next month following the end of samples, what is the best method for this? Also how do I verify whether the volatility is dependent on market liquidity, based on this data. Can someone point me to easy tutorials/books that allows this kinds of data analysis. I have a good background on statistical data analysis but I am a complete noob to financial data. Any help will be much appreciated
Answer: If you are familiar with programming (which is required to deal with HF data), I would strongly recommend you to use the "HighFrequency" R package.
It includes a lot of procedures to clean HF data and to estimate volatility.
You can find here a very good tutorial about the package.
If needed you can find here some good tutorials for R.
Credits: The package has been developed by Kris Boudt , Jonathan Cornelissen , Scott Payseur,Giang Nguyen and Maarten Schermer .


How to proceed when denied co-authorship for a research paper?

Question: I have contributed significantly to the paper and I was not listed as co-author instead I am listed in acknowledgement section in the end saying that thanks to my preliminary studies. I had sent the data to my supervisor before I left the lab and I have all evidences of work reports and weekly meetings. They repeated my experiments with my optimized conditions and produced their results in the manuscript and included few new data. I could not find much difference between my results and results obtained from their repeated work.
I am really disappointed with whole situation which I feel went against ethic science for a significant contributor to be dropped from the list of authors. There was no response to my e-mails from corresponding author that I asked for justification. Please suggest me accordingly, what can I do further, the manuscript is already in ASAP.
Comment: What field is this in.  it could be that the data is similar, but their interpretation of the data is what the paper is really about, and in that case you may not deserve authorship.  In addition, some conventions require you to have read and written at least part of the paper before it was submitted.
Answer:
They repeated my experiments with my optimized conditions

It sounds like they repeated the work you did and acknowledged you for running the preliminary experiment. While it sounds like you could have been included to a greater extent in the "new" research, they decided for whatever reason to not include you. By recollecting the data, they have essentially eliminated your contribution. In addition to the acknowledgement, providing a reference/citation to your "preliminary" data would not be out of place, but if those data are not publicly available (and in some fields in a peer-reviewed and/or archival form) providing a reference may be out of place.
There are really two things you can do. The first is talk to your former supervisor, not the corresponding author, about authorship on the current work and any other work you were involved in while working in the lab. It is quite possible the corresponding author does not really know who you are or what your role in the preliminary studies were. The second thing you could do is attempt to publish your data first. You would of course want to include everyone who deserves authorship (which likely includes your former supervisor) and this could get messy. Getting to the finish line first could be difficult. You may be able to get the work "published" on a non-peer-reviewed preprint service (e.g., arXiv) first, but the value of those types of preprints are very field dependent.
Answer: I agree with the comment given, contributing data doesn't qualify you as a co-author. However it would, most likely, be good practice of them if you would have had the opportunity to contribute enough of to the paper to meet the standards. But, of course, if this is possible also depends on the circumstances you left the group in.
If you still work at the same institution you could contact the ethical commission (you could also try if you do not work there anymore).
How ever adding an author after submission is not something most journals would consider
Answer: My view is that more important than co-authorship is an adequate recognition of your contributions. From what you have written, an honest statement about your contributions may show that it was actually your work which was more important than that of the other authors.
(I am not able to address the issue of the coauthorship itself as such -- as important/practical as this could be in real life).


Bootstrap theme that looks like sharepoint 2013

Question: We created a provider hosted webapp in sharepoint 2013. The webapp is accessed thru an iframe. We use twitter bootstrap for the UI in the webapp.
Does anyone know of a bootstrap theme that makes the app look like standard sharepoint 2013 UI?
Answer: Assuming you mean that the colors should match the colors of the current SharePoint theme, you can use this approach - How-to-Easily-Bring-SharePoint-2013-Theme-Colors-Into-Your-Apps
When you have a IFrame only app,  you can use this to inherit the CSS from the parent - https://stackoverflow.com/a/4613196
and apply some SP classes to your markup to get the colors.
If you just want to have the colors that are definded in the standard Composed Look "Office" you can easily create your own theme based on the corresponding colors and fonts - Themebuilder
If you want a more complex solution you have to point out what exactly you want as result.
Comment: Thanks for the feedback, but we do have to use bootstrap. I'm thinking of using one of the Metro themes or just setup a new Sharepoint 2013 theme.
Comment: All of my proposals were meant to be used with bootstrap.


How can I recover more quickly from leg-intensive cardio workouts?

Question: It seems that every time I do a leg-intensive cardio workout, like stair climbing, intense elliptical machine, or running more than 3-4 miles, my legs take forever to bounce back.  They don't hurt so much as they just feel heavy and lethargic.  I try to do cardio every other day, but my legs seem to only allow intense cardio once or twice a week.  What are some strategies for combating this, so that I can do intense cardio at least 3x a week?
Comment: Why do you want to do cardio 3X a week?  Maybe you're just hurting yourself?
Answer: This might be tough to hear, but you should also consider the fact that not everyone is gifted with a body that can handle pro-athlete levels of activity.
If your legs are constantly tired/heavy, and you see no improvement (and ESPECIALLY if you see backwards progress), I would say your body is telling you it's not ready for that level of activity (at least not yet).
Back it off a bit, let your legs recover, and try easing into things. I'm not saying you shouldn't push yourself, but at the same time, there is such thing as overtraining, and at that point all the time you put into your training is counterproductive and wasted. Stubbornness can be the enemy of progress sometimes.
Comment: I don't agree with the first paragraph of this answer but I do with the rest. With an appropriate training program being able to run for 30 mins 3 times a week should be achievable for most people - and is certainly not pro-athlete levels of activity.
Comment: @parkker007, I have overtraining and when I ease back into my training, I have really trouble dealing with the question of pushing myself VS. overtraining. As in, I want to push myself, but how do I push myself to the point that I still make improvements in my training but am not overtraining? I always seem to cross that thin line into overtraining.
Thanks!
Comment: @Bee - first things first: make sure your nutrition/resting is adequate. If you're pushing yourself in the gym, the limiting factor is going to be your recovery. If you're truly giving your body the recovery it needs and you're still seeing regressions in your training, you just need to suck it up and cut some training time. It takes patience to find the level of training your body can handle.. sorry I can't give you a more specific answer, but that's the way it is :)
Answer: I have a similar issue as I regularly play football so I try to run hard. I experience soreness especially in my thigh and calf muscles.
I suggest you do some warm down and stretching after the exercise, this will help you bounce back sooner.
I also have the benefit of a back yard swimming pool and after football I do a few laps and also some running in the shallow end. The combination of the cold water and the light exercise seems to be a big help. Maybe you can join a gym that also has a swimming pool.
Also be careful as your body might be telling you that it can only handle two sessions a week.
Answer: A cold whirlpool daily does wonders for recovery.  I always experienced tired legs and aching knees during my entire football career.  Only a dip in the cold pool would help refresh my legs.  It forces increased bloodflow to the legs, which results in better recovery.
Without access to a cold whirlpool, a cold bath in which only your legs are immersed or perhaps a quick swim in a pool of any kind would be helpful.
Answer: A lot depends on what you mean by "intense" leg-based cardio, and what the rest of your fitness support is like.  Consider the following options:

Do you stretch carefully before and after?  And warm up your legs before and cool down after?
Reduce your per-workout intensity by 20-40% and see if that helps.  Over time, ramp up.  Using a treadmill's display is key for this.
Are you eating a good diet to support recovery?  Protein, vitamins, replacing glucose and electrolytes, drinking enough water, a varied diet, etc.
Are you getting enough sleep and rest to support recovery?  (say 7-8 hrs/night)
Have you tried massage on your legs, significantly elevating your legs while resting, hot or cold water therapy (in shower or bath).
How long have you been training?  Sometimes the first few months things are quite clunky and after training one feels pretty low energy, either in body parts or all over.  Maybe you are just not there yet, but will be.
Answer: As most people are saying, you need to make sure you warm up, stretch before, and stretch after. There are also a few other things you can try:
Is cardio the only type of exercise you get? I'm a runner, and it's very important to also do some leg strengthening exercises to build muscle (e.g. squats, lunges, etc). If you're not doing these, give it a try on your off days. If you are doing it - how often? Perhaps the reason why you can't handle cardio every other day is because you're also doing other types of exercises that work your legs on the days you're not doing cardio?
In addition to normal stretching, have you tried tennis ball stretching? (Scroll down for the video demo) This is especially important for your quads. Lay on the floor face down, put the tennis ball under your quad, and bend and straighten your knee. It gives you a deeper stretch, kind of like you're ironing the muscle. You can also get foam rollers or noodles (the kind that are used as floats in pools) and roll back and forth on those (this is really good for your IT band).
Make sure you're eating good recovery foods too - in my opinion low-fat chocolate milk is the best recovery drink to have after a hard workout, but you need to make sure you're eating a balanced diet as well.


Trouble finding good letter writers for math grad school due to switching programs

Question: I'm planning to apply to top US grad schools in the fall, and out of all the required documents, I would say that my weakest link would be in the quality of my recommendation letters.
I'm currently planning to ask the following people:

Professor X: I'm doing research with this person in the summer, and we already have a significant result that we are planning to turn into a joint paper. (Subject: discrete math)
Professor Y: I received an A+ in this person's undergraduate analysis course last year, and he offered to write a letter of recommendation to those who received an A+ in his course.

Then, the rest I'm not sure about, I have the following to choose from:

Professor Z: I did a research project with this professor in number theory, but it was more like a reading course. I don't think I left a significant impression on him, since the topic I was reading was fairly elementary in the field.
Manager A: I did an internship under this person at a Big 4 Tech company last summer, and he had high reviews of me, and gave me a returning offer at the end, which I declined.
Postdoc B: I did a research internship with this person in applied computer science (not math heavy) two summers ago, and it culminated in a joint conference publication.

The problem with Manager A and Postdoc B are that they are not professors, and I did not do any pure mathematics with them, which I heard should not be a part of my application package.
I was briefly in engineering. I switched into my current math and computer science program about 1.5 years into my undergraduate degree. I started becoming serious about going to math grad school last summer, after testing the waters with industry.
My GPA is probably among the top 1%, and I have taken most of the upper level undergraduate math courses. I will be taking some graduate level math courses at the same time as my applying to graduate schools in the fall.
I've also been learning more graduate number theory material with a mentor on the side, and will be writing some expository pieces. But again, a graduate mentor cannot write me letters of recommendations.
Of course, if I choose Professor X,Y,Z, then I will have 3 letters, but only one of them will be strong. Should I explain this in my statement of purpose? Can I still fix this situation by working on a more meaningful research project in the fall?
Answer: I think X, Y and Z with both X and Y strong will be just fine. Few undergraduates have had enough contact with faculty to generate three strong letters.
The work you did with A and B  will be on your CV and you can discuss it in a cover letter.
Good luck.


Can powdered formula spoil on very hot days?

Question: During the last few days the temperature where we live has been going up. During the day it is around 40 degrees Centigrade. Will the tub of powdered formula I have been using for my four month old go bad at that temperature?
Comment: Welcome to Parenting.SE, Meenakshi! A similar question has already been asked (see [Is milk powder left in a hot car going to go bad?](http://parenting.stackexchange.com/questions/14502/is-milk-powder-left-in-a-hot-car-going-to-go-bad)) -- however, you're asking about consistently storing formula at a high temperature and so this seems fairly different.
Answer: I looked at one manufacturer's recommendation for storage of their formula products to get this answer.

For unopened cans of Similac® infant formulas, most desirable  storage
  temperatures are between 13°C [55°F] and 24°C [75°F], but between 0°C
  [32°F] and 35°C [95°F] is also acceptable. Storage at extreme
  temperatures compromises the quality of the product. For that
  reason, you should not use infant formulas stored for long periods at
  extreme temperatures.

Your brand may be different, but powdered infant formulas all follow the same general recipe. Unless the manufacturer explicitly says so, there is a risk that high temperatures can affect the formula and so you should find somewhere to store it that is at least consistently below 35°C, and preferably below 24°C.
To make things more complicated, however:

Do not store cans of powder infant formula in the refrigerator.
  Instead, store them covered, in a cool, dry place.

If you can find a cool, dry place (perhaps a kitchen cupboard that doesn't get frequently opened during the day), that is the best solution until the heat wave is over.
Comment: What is interesting is that this also means storing it in the car during freezing weather is also not recommended. I wouldn't have thought about that with powdered formula.


Disable "open with" in chrome

Question: How do I disable the "open with" feature in chrome on android? An alternative would be to have chrome itself in the list of alternatives.
Comment: Can you please rephrase the question as it is unclear. Do you want to stop Chrome opening web pages by default, and instead prompt you how you want to open a link?
Comment: No, but I want the option of opening a link in chrome itself.
Comment: Does it currently open somewhere else? You can set your default apps in Settings > Apps.
Comment: I am only getting the option to open some links using external apps even if chrome would be able to open them itself.
Comment: When you have an app installed which is a dedicated app to handle certain links, you'll be given options how you want to open it. Example, if you have twitter app installed and you tap on a twitter link, it can sometimes ask you where you want to open it. You can set them in Settings > default Apps > Opening Links and set "Open supported links" to "Don't open in this app".
Comment: I know all of this. The problem is that I cannot open those links in chrome, given the options presented.
Answer: Apps has an option as 'In-App Browser' which enables an app to open links within the app and it can be disabled by disabling 'In-App Browser' in that particular Settings of App.
For another thing like clicking twitter links, for ex-  'https://t.co/something' we have two ways either clear default app in settings that enables system to ask you from which app you want to complete this task or copy the link(s) and open it in browser itself.

Disable "open with" in chrome


Why are so many bed surfaces black? Would white help?

Question: It occurred to me after recalling cooling problems in the layers near the bed that many popular build surfaces (e.g. BuildTak clones) are black, which should radiate the most heat - onto the part being printed, which is generally undesirable. Is there a reason for this? Are there (white) build surfaces designed to minimize radiation of heat that might help avoid cooling problems in the initial layers?
Comment: I suspect the difference would be negligible, but now I want a white one, just because it would be easier to see the print for most colors (except white, obviously)
Comment: I think black surfaces absorb and retain heat better but this is just knowledge from high school days.
Comment: My bed is blue.
Answer: I believe that the color is just a design choice, and doesn't have that big of an effect on the print itself. Changing the color wouldn't have an effect on the print itself. If you are looking for a solution to minimize radiation of heat going up to the build, you could either lower the heat of the bed, or you could go into the advanced print settings and change the bed temp after the first couple layers.


What has changed in Terminal.app in OS X 10.8?

Question: Just upgraded OS X to Mountain Lion and noticed that Terminal.app version has changed from 2.2.3 to 2.3. Unfortunately, can`t find any information about what has changed. Do you know if there is any place that provides very detailed changelog regarding OS and Apps?
Answer: The new feature is that it works with mountain lion. Apple updates to a new minor release version number of terminal with every new edition of osx
Answer: Probably very little. Certainly does not look like much has…
On the second thought: did previous version allow to "Open man Page" for selected word when you double-tap? [Checked, it did, this was added in Lion]


What do you call it when some group is feeling self-satisfaction by praising themselves?

Question: What do you call it when a group of people is feeling self-satisfied and praising themselves, even though others don't think them praise-worthy?
Comment: It's not an idiom (I like @donothingsuccessfully's answer below), but 'self-congratulatory' can be applied to a group.  It, too, isolates the opinion to the group.
Answer: Mutual admiration society is apparently an expression in English, used at least as early as 1824.

A group of two or more people, in a workplace or other social environment, who routinely express considerable esteem and support for one another, sometimes to the point of exaggeration or pretense.

I was about to comment about the Swedish expression "klubben för inbördes beundran" that translates to pretty much the same thing, and found the English version while researching it.
Comment: The term was certainly popularised, and probably coined, by [Oliver Wendell Holmes](http://www.oldandsold.com/articles35/american-lit-18.shtml) in the mid 1800s, in reference to the "literary set" of Boston, where he himself was based. It seems he actually quite liked being in that society, and enjoyed giving and receiving praise among peers.
Comment: One might take one of @Jim's suggestions and place it in front of this one if you want to strongly make the point that the Mutual Admiration does not necessarily extend beyond their society.
Answer: The potentially offensive phrase "circle jerk" literally means group masturbation, but is used metaphorically to describe this situation.
Comment: This is more appropriate for the OP, given the presumed disapproval of those 'outside' the circle.
Answer: I propose that self-congratulatory or self-important best capture a person who is complacent and self-praising. Words like smug or preening are more about the manner in which someone expresses conceit.
Answer: You could try, smug, pompous, conceited or vain.

smug : highly self-satisfied
pompous: having or exhibiting self-importance
conceited: : having or showing an excessively high opinion of oneself
vain: having or showing undue or excessive pride in one's appearance or achievements
Answer: Besides smugness, consider crowing,
preening, and bragging.  Brag means "to boast; to talk with excessive pride about what one has, can do, or has done."
Answer: Such people are said to be in an echo chamber, in the figurative sense. Or such a group can be called an echo chamber.
Echo chamber -- Wikipedia

An echo chamber is a metaphorical description of a situation in which information, ideas, or beliefs are amplified or reinforced by communication and repetition inside a defined system. Inside a figurative echo chamber, official sources often go unquestioned and different or competing views are censored, disallowed, or otherwise underrepresented.
Answer: Here, it could be a group, or just one person praising themselves...

blow (one's) own horn
To boast or brag about one's own abilities, skills, success, achievements, etc.
The Free Dictionary
Answer: You could always say that they were / are gloating.
Definition of 'gloating':

to observe or think about something with triumphant and often malicious satisfaction, gratification, or delight


Monumentum spelled as monimentum

Question: I saw a great number of Latin inscriptions in a cathedral on Malta, dating roughly between 1500 and 1800 CE.
There were at least a couple of instances of the word monimentum, but saw no monumentum.
Is the spelling with I instead of U common in the Latin of that era?
I do not recall seeing it before, and I am under the impression that it is classically exclusively monumentum.
Answer: Considering that this is a word-internal short vowel before a labial consonant, it looks like this vowel comes from the "sonus medius".
Unfortunately, I don't know that much about the patterns of variation in the use of u vs. i in the spelling of words like this. I was able to find the following passage in B. Kennedy's Latin grammar, Fifth Edition (1879):

the middle sound between ĭ and ŭ [...] exists almost exclusively before labials [...]
  Inscriptions shew that the forms with ŭ prevailed in E. L., and R. L., those with ĭ in and after the Augustan age, for which the Monument of Ancyra, as edited by Mommsen, is the best authority.

(pp. 31-32, §12)
Allen's Vox Latina also says that u variants tend to be older, and i variants more recent: he says "the earliest example for this change is from 117 B.C., with inscr. infimo beside infumum" and "in some cases, although the change took place, the older u form came to be preferred (e.g. documentum)" (p. 57).
Speaking generally, Allen writes that

The change of official orthography from u to i in such words is said to have been due to Caesar (†Varro, cited in Cassiodor(i)us, K. vii, 150; cf. Quintilian, i, 7, 21); and Cicero is said to have considered the older pronunciation and spelling as 'rusticanum' (Velius Longus, K. vii, 49). Velius Longus (67) also mentions that Augustan inscriptions still showed u; but i is in fact regular in the Monumentum Ancyranum.

(p. 58)
I wasn't able to find the word monumentum/monimentum anywhere in the text of Res Gestae Divi Augusti, so the  Monumentum Ancyranum doesn't seem to provide any evidence about this particular word.
The Lewis and Short entry for monimentum simply says "see monumentum" without any further comment; the entry for monumentum includes some quotations that use the monim- form.
There seem to be a fair number of hits for both monum- and monim- in the PHI Classical Latin Texts database: there were 581 matches for$monum, but also 123 matches for #monim, including some from the works of Cato, Plautus, Caesar, Cicero, Ovid, Pliny, and Virgil.
Based on this, it seems to me that monimentum existed in the classical period, and it doesn't seem to have been extremely rare or considered an improper form. I'm not sure how its frequency changed in later time periods.
Comment: Agreed. The reason for monimentum in Renaissance-era inscriptions is almost certainly their awareness of these passages you cited that favor that spelling. The Renaissance Latinists were enamored with minutiae of this sort.
Answer: Since your question is about the use of i-u in Post-Classical Latin, I will address that point only and not its use in Old or Classical Latin.
I don't have enough information - yet - about the specified time period and place (1500-1700, i.e. Neo-Latin in Malta), but here's what I've been able to find about Medieval Latin.
Peter Stotz (Stotz 1996, Handbuch zur lateinischen Sprache des Mittelalters, volume 3, p. 42) writes the following:

"Das Schwanken von i und u for Labialen im röm. Latein äußert sich im MA nur noch in Form vereinzelter Schreibung, welche durch den uneinheitlichen Befund in den damals vorliegenden älteren Texten verursacht sind.

in English: The alternation of i and u before labials [found] in Classical Latin manifests itself in the Middle Ages  only in the form of isolated spellings, which is caused by the inconsistent findings in the older texts available at that time.
cf. "Gewisse Schwankungen zwischen ĭ und ŭ in älterer Zeit haben sich durch ihr Vorkommen in den älteren Texten ins MA fortgeschrieben" (p. 69).
Here's the relevant entry from Niermeyer's Mediae Latinitatis Lexicon Minus:

We need to look it up in part 2 of Ijsewijn and Sacré 1998 Companion to Neo-Latin Studies for Neo-Latin data - I don't have a copy at home.
Re: Neo-Latin editorial (spelling) practices, here's what Tom Deneire (Deneire 2014) says:

"Unlike classical texts, for which the original spelling can almost never be ascertained, Neo-Latin texts often exist in authorial copies (either in manuscript or in print) that reflect the author's particular spelling of the Latin language. This spelling might be based on a consciously adopted system [...] or be completely haphazard [..] . In this way, one may encounter mediaeval remnants (lachryma), forms inspired by the vernacular (ottinere), hypercorrections (caeteri), just typical Neo-Latin spellings (caussa), or as regular a phenomenon as the reversal of u and v that produces spellings like vua ('grape')" [emphasis mine - Alex B.].
Answer: Robert Ainsworth's Dictionary, MDCCXXVII,lists mŏnĭmentum first with mŏnŭmentum second, and included in only one of the quotations (Cic.).
mŏnĭmentum examples (various meanings) from Horace, Virgil, Cicero, Tacitus, Ovid, Plautus.
This is followed by entries (sharing etymology from moneo) for monitor, monitio, monitus.
mŏnŭmentum gets a shorter entry. It gives doceo as the paradigm for that formation, but points out that derivatives of doceo form docu-
(videlicet: dŏcŭmen, dŏcŭmentum,) For meanings and citations it refers back to monimentum. But Ainsworth may be eccentric, or obstinately pedantic in his preference; I don't have access to 16th, 17th, 18th Century editions of Latin authors.
Sir Christopher Wren's tomb in St Paul's Cathedral, 1723, bears the inscription Lector, si monumentum requiris, circumspice.

Monumentum spelled as monimentum


Effect of interest rate on options prices

Question: This might be another basic derivatives question. When interest rate rises, stock prices generally fall. Assuming an option's underlying is a stock, this should lower the option's price as well. However, according to many sources, when interest rate rises, options prices rise. What causes this and does this actually cancel out the effect of lower underlying prices?
Comment: "When interest rate rises, stock prices generally fall" -
this is a very strong statement. these effects are difficult to confirm, see e.g. Bernanke's [What Explains the Stock Market's Reaction to Federal Reserve Policy?](http://www.federalreserve.gov/pubs/feds/2004/200416/200416pap.pdf), they look at _unanticipated_ shocks to interest rates. if the rates decline, and this decline is unticipated you're not going to see the stock price movements
Answer: Personally I think there is no easy answer to this question.
Economically a rise of interest rates often means an increased demand for capital. Banks need more money to lend to the industry thus they increase rates to entice consumers.
On the other hand a demand for capital on the side of the economy often means increased market activity - companies want to invest more. More market activity can translate into higher market volatility. And higher volatility translates to higher option prices.
Also, let us assume stock prices do fall because of rising interest rates. It has been observed that market volatility goes up in a bear market. (e.g. confer the following book - page 196) Once again you would have a higher volatility and thus higher option prices.
How an option reacts to interest rates depends on it's maturity and also on the type of option.

Generally: The higher the maturity the more sensitive the
  product is to changes in the interest rates (for you discount over a
  longer period of time)

I can recomend this mathematica tool for the B&S Model. You can play around with it to get a feel for how option prices react to changes in different parameters. If you crank up the maturity you will notice the price surface will shift significantly more if you change the interest rate. For a low maturity the changes will be minuscule
Answer: By derivating the Black-Scholes formula in function of r (ρ=∂C/∂r), you get
ρ_call=0.01TKe^(-rT) N(d_2 )=ρ_put+0.01TKe^(-rT)
You can see that call prices increase (and put prices decrease) if interest rates (risk-free) increase.
Answer: Actually, the answer to this interview question is that to replicate a call, for example, you hold the stock and you short a bond. If interest rates rise the price of the bond falls. But holding a Call means being short on the bond so the value (=price) of the call rises.
It is the opposite for a put.


What are the advantages of barker sequence over marker sequnce?

Question: I read that barker sequence is used for synchronization among other uses.  Barker sequences are rare and they have special properties - this part I understood.  I am missing some thing when I think about how they score over simple marker sequences for synchronization.  You want to know where the information bits start - start with a marker sequence preferably which does not occur in the information.  And you can synchronize.  How do barker sequences score over marker sequences?
Answer: A big advantage of Barker Codes over a generic marker is strong correlation when the codes are aligned and very low correlation for all other shifts, even by one sample.  This offers increased resistance to bit errors that would otherwise cause a false detection.
The presence of a Barker sequence can be optimally detected using correlation, which is the process of multiplying bit by bit the received sequence to the reference Barker code sequence at a given alignment and summing the result of the multiplications (multiply and accumulate). With a Barker sequence, you will get maximum correlation when the received sequence and reference sequence are aligned, and near 0 for all other shifts. This is an ideal characteristic for synchronization, and not a property of generic marker sequences.
Depending on the noise resistance desired, longer codes can be chosen, and/or code sequences can be repeated. Like the use of a generic marker sequence, the Barker code itself would not be an allowed pattern in the data payload, or properly escaped.
As an example, 10110111000 is an 11 chip Barker Code. As an easy way to explain the correlation as a multiply and accumulate, replace all the 0's in the sequence with -1, and all 1's in the sequence with +1. Therefore when correlating the multiplications before summing are an x-nor: 0x0 =1, 0x1=0, 1x0=0, 1x1=0. For demonstration, consider a sequence of three repeating Barker codes for a header:
received sequence
101101110001011011100010110111000
As the sequence is received, we will correlate it by shifting it against our reference sequence and performing the multiply and accumulate for each shift.
Case 1 aligned:
When a reference code is aligned with the received code, the correlation (multiply and sum) is:
101101110001011...
10110111000
1x1=+1
0x0=+1
1x1=+1
1x1=+1
0x0=+1
1x1=+1
1x1=+1
1x1=+1
0x0=+1
0x0=+1
0x0=+1
Sum=+11

Case 2 misaligned by 1 sample:
01011011100010...
10110111000
1x0=-1
0x1=-1
1x0=-1
1x1=+1
0x1=-1
1x0=-1
1x1=+1
1x1=+1
0x1=-1
0x0=+1
0x0=+1
Sum = -1

The same result of -1 occurs for all shifts, except when the code aligns at which point the correlation is maximum (the length of the code).  Since the length of the code is odd, the correlation cannot sum to the ideal value of 0, but gets quite close! Also note that the code can be inverted, and in that case it would sum to -11 when aligned (for a maximum distance of 22 between positive and negative copies of the code).
Maximum Length Sequences (generated with Linear Feedback Shift Registers) also have this shift-correlation property and include significantly longer sequences than Barker codes, which finds application in GPS and Direct Sequence Spread Spectrum communications where signals are received below the noise floor and recovered using these correlation techniques.
Another view from coding theory is the concept of Hamming distance.
(see [https://en.wikipedia.org/wiki/Hamming_distance] 1) To be consistent for that approach we would need to repeat what I did above with symbols 0 and 1 and use an x-or to do the multiply. If the symbols in two sequences are different a 1 is added, if they are the same 0 is added (x-or). The Hamming distance is the total addition of the x-or results between the two sequences.  If every symbol didn't match (maximum negative correlation) the Hamming distance would be 11, and if every symbol matched, the Hamming distance would be 0 (for the 11 chip Barker sequence I used).  Therefore the Hamming distance between 01001000111 and 10110111000 is 11 (maximum distance possible), and the Hamming distance between the code and cyclically shifted versions of the code would be approximately half way in between: For example, the Hamming distance between 01001000111 and 10010001110 = 5. In fact, since the Barker code has noise-like properties, the likelihood is highest for the distance to be near the middle for all random patterns such as what may be represented by our data payload.  It is much more likely that the Barker code will have distances between 4 and 8 to patterns in our data but much less so from 0-3 and 9-11; but that still can an will happen, especially with such a short sequence, unless we encode our data to ensure those sequences do not occur unless bit errors existed. The concept of Hamming distance, and choosing code words of maximum distance is a foundation of error detection and correction.  The bigger the distance, the more errors we can correct (see the reference for specific details on all of that).
Comment: :Thanks for taking the pains to explain.  Autocorrelation properties I know.  Some food for thought you have given is: maximum length sequences and what happens if you repeat the Barker.  But I want to investigate what happens if some bits of barker transmitted change and it is compared with barker reference.  Is there literature on this?  Please share any pointed references on this if you have.
Comment: I think in view of my comments above, cross correlation of the sequence also becomes important.
Comment: Hi Seetha- Yes cross correlation of the sequence to itself is what I described, and cross correlation to other sequences including your data itself is also very important as you noted. Given the way I explained (with the +1 and -1 symbols), for every bit that is in error, the correlation will reduce by 2.  But I added a description from coding theory using "Hamming Distance" which gives another view specific to error correction and detection.
Answer: One benefit is reduction of false-positives when there are bit errors. Bit errors in the sequence may increase the value of a sidelobe and even make it equal to or larger than your detection threshold. The smaller the ideal sidelobe, the less likely this is to happen.
Another benefit is that they have nice spectral properties, since their autocorrelation resembles that of white noise.
Comment: :Barker has good autocorrelation properties.  But suppose that some, may be 1 or 2,  errors occur randomly in the sequence, does it still retain the good autocorrelation property?


Ingesting professional sony beta and sx tape into iMac thru Canopus ADVC 110

Question: I'm trying to capture sony beta and sx tape into my iMac. I know I need a device between the deck and computer. I believe that device is the Canopus ADVC 110 converter (have yet to purchase this.)  Will I be able to cable from that converter directly to the thunderbolt port on the iMac? There are no firewire ports on my iMac. Pretty confused on this process. thanks!
Comment: The Canopus ADVC 110 will output DV video which may or may not be desired.
Answer: If you have firwire device but no firewire port you need an adapter. Apple offers one:
http://store.apple.com/us/product/MD464ZM/A/apple-thunderbolt-to-firewire-adapter
If you tape deck is offering an output that the Canopus supports you will be able to capture your tapes that way.
Alternatively you might want to look for a USB based solution that might be cheaper than using this device with an adapter.
Comment: ok thanks! So the adapter carries both audio and video from the Canopus converter? Will I need any to download any program if I'm capturing directly to an external hard drive plugged into the iMac?
Comment: Also could you recommend a usb solution? thanks!
Comment: No, if your hard drive is internal or external makes absolutely no difference when capturing with any sort of device.
I can't really recommend you anything as I dont know what you are playing back from but all you need really is a device that can capture analog video, like the Canopus.
A cheap capture stick can do the same but maybe not with the same quality. Though that can be delectable if you dont plan on further editing the footage and just want to save some home videos.
http://www.amazon.com/Elgato-Video-Capture-Device-10020840/dp/B0029U2YSA/
Answer: I would suggest looking for an interface that offers SDI inputs (as I suppose both your SP and SX players have SDI outputs) with which you will have better results than with a composite inputs as is on the Canopus product.
SDI interface will allow syncing your interface with the player, and get embedded audio directly in the SDI stream.
An example of such interfaces is https://www.blackmagicdesign.com/products/ultrastudiousb3, other products might exist.


Does a type rating give a person the privileges of an instrument rating in any category or class of aircraft which he/she is certificated in?

Question: Suppose someone obtains a PPL-ASEL, then obtains a type rating in an aircraft requiring that rating e.g. jet, etc.  This type rating functions as an instrument rating, allowing the pilot to fly the new aircraft under IFR.  But does said type rating then grant the pilot the privelages to operate ANY appropriately equipped airplane single engine land under IFR as well?
Comment: To clarify, you are asking about a type rating added to a private certificate exclusively, not a type rating ride that doubles as an ATP check ride? The ATP Certificate does give instrument privelages.
Comment: Under which jurisdiction?
Comment: United States of America
Comment: I'm pretty sure you'd have to have an instrument rating first...
Comment: No I was informed about this by an FAA ATP examiner who also issues type ratings on the Lear 25,35, and 65 airplanes.  The type rating also functions as an instrument rating and is required to do so as the airplane's flight envelope extends into Class A airspace requiring IFR operations there.
Answer: 61.63(d)(1) requires that if you don't have an ATP that you hold an instrument rating to obtain a type rating. The type rating itself does not grant instrument privileges.

(d) Additional aircraft type rating. Except as provided under paragraph (d)(6) of this section, a person who applies for an aircraft type rating or an aircraft type rating to be completed concurrently with an aircraft category or class rating—
(1) Must hold or concurrently obtain an appropriate instrument rating, except as provided in paragraph (e) of this section.

Paragraph (e) exempts aircraft incapable of instrument maneuvers and instrument flight from this requirement.
This does mean that you can do the instrument checkride concurrent with the type rating. If your hypothetical PP-ASEL gets typed in a citation, he will end up with a PP-ASEL with instrument airplane rating and the citation type.


How is NAD+ used in lactic acid fermentation after it is oxidized from NADH?

Question: I am confused with the whole process of glycolysis and the fate of the products of this reaction. So, I understand that anaerobic glycolysis results in 2 pyruvate + 2 NADH and 2 net ATP. Is the whole anaerobic purpose of glycolysis to make the 2 net ATP? Then pyruvate and NADH are waste products? Also, pyruvate then reduces to lactic acid. What is the need for this? NADH is oxidized to NAD+. How is NAD+ used? Also, lactic acid is eventually converted back to pyruvate through Cori cycle. How is that pyruvate used?
Comment: I have altered your question to indicate that it applies to anaerobic glycolysis.
Answer: Anaerobic Glycolysis
As this question refers to glycolysis in the context of lactic acid fermentation it clearly relates to anaerobic glycolysis, which is why I added that to the question.
I believe it is correct to regard the primary purpose of anaerobic glycolysis as being to generate ATP for the anaerobic organism or tissue.
To understand the roles of NAD and lactate in this process you need to consider the chemistry. The conversion of glucose to pyruvate is an oxidative process, with the oxidizing agent being NAD+, which itself is reduced to NADH. For glycolysis to continue the NADH must be reoxidized to regenerate NAD+. This is the primary purpose of the reduction of pyruvate to lactate and is summarized in my own diagram, below.

So, the answers to your (paraphrased) questions "what are NAD and lactic acid needed for?" and "are they waste products?" are:

NADH isn't needed for anything — it's the consequence of the oxidative function of NAD+. No, it is not a waste product — it has to be reoxidized otherwise glycolysis would stop for lack of oxidising power.
Lactate also is not needed for anything, as evidenced by the fact that other reduced products of pyruvate are produced in different organisms, most notably ethanol in yeasts. Ethanol can certainly be regarded as a waste product, although the carbon skeleton of lactate is salvaged in multicellular oxygen-breathing organisms.

The so-called cycle of Cori & Cori
In my opinion it is best to approach glycolysis as I have done above, without reference to the tissue or organism, so as to understand the essential features of the process.
In the specific case of mammals, some tissues perform glycolysis anaerobically, e.g. the red blood cell (which lacks mitochondria) or rapidly excercising muscle (where the blood supply and number of mitochondria are not sufficient to generate ATP for muscle contraction. The liver, in contrast, has a plentiful supply of oxygen and hence NAD+, and so can reoxidize lactate to pyruvate if the former is transported in the blood from the anaerobic tissue to the liver, salvaging the carbon skeleton.
Under conditions of low blood sugar (e.g. starvation) it is important that the pyruvate be reconverted into glucose in the liver by gluconeogenesis, rather than be converted to other products, and the glucose is released into the blood. In this case one goes full circle, this process is generally referred to as the Cori Cycle. I always avoided this term myself in teaching students as I found it caused confusion with cycles such as the tricarboxylic acid cycle and the urea cycle, where all the chemical interconversions take place in the same tissue.
Footnote: Glycolysis under aerobic conditions
Under aerobic conditions (e.g. in the liver after a carbohydrate meal) the purpose of glycolysis is not primarily to generate energy but to utilize the glucose, storing it as fat (after glycogen capacity is reached) or using it to synthesize intermediates. There are different fates for the pyruvate (acetyl-CoA is shown), but lactate is not one of them as the NADH can be reoxidized far more efficiently in the mitochondria, with molecular oxygen being the ultimate oxidizing agent.

Text References
Berg et al. Section. 16.1 (5th ed.) covers glycolysis in great detail under aerobic conditions. The lactic dehydrogenase reaction is given little emphasis, but can be found in section 16.1.9.
Comment: You understood exactly what my question was even when I myself was confused about what my question exactly is. Thank you so much.  Your diagram helped. Now, I understand your diagram and why different steps are needed, but can you please help me understand the bigger picture. So the cycle in your diagram occurs when there is a lack of oxygen, i.e while exercising. But what happens where O2 is present (when we are not exercising) then there shouldn't be any lactate (b/c we dont get sore when we are sitting), if there is no lactate, means NADH doesnt get converted to NAD?
Comment: @JagmeetSingh — Happy to be of help. I've added a small section with a diagram indicating what happens to the NADH under aerobic conditions. The various possible fates of pyruvate (and glucose 6-phosphate) belong in an answer to a different question. If you have not yet met oxidative phosphorylation and the TCA cycle, then you will need to take your time learning about them — very important, but lots of detai.
Comment: So just to clarify: Glucose gets converted to pyruvate and in absence of O2, it goes through fermentation BECAUSE it produces at least 2 ATP(?), and when there is O2 available, it proceeds to carboxylation of pyruvate --> Citric acid cycle and so on. My only confusion now is that why does glycolysis need to occur (anaerobically) if it can not even proceed to cellular respiration.
Comment: I meant "decarboxylation" above and not "carboxylation".
Comment: Actually, I saved you some headache.
http://antranik.org/cell-respiration-part-1-anaerobic-respiration-glycolysis-and-fermentation/
This website it explained it well.
Comment: @JagmeetSingh — Note that under aerobic conditions in the liver there are at least two other pathways glucose may be metabolized by other than glycolysis. Also it is precisely 2 net ATP in anaerobic glycolysis — the ones generated through the capture of phosphate in the GAPDH reaction.
Answer:
The whole purpose of glycolysis is to make the 2 net ATP, right?

No, actually it's breakdown of glucose as the name suggests, so as to provide pyruvate, whose fate depends on cells need and environment.

Then pyruvate and NADH are waste product?

Why? They are just intermediates which can be utilised in tca, or cori cycle or in any other metabolic pathways as cell needs.

Also, pyruvate then reduces to lactic acid. What is the need for this? NADH is oxidized to NAD+......

Wikipedia says:

The production of lactate is beneficial because it regenerates NAD+ (pyruvate is reduced to lactate while NADH is oxidized to NAD+), which is used up in oxidation of glyceraldehyde 3-phosphate during production of pyruvate from glucose, and this ensures that energy production is maintained and exercise can continue. (During intense exercise, the respiratory chain cannot keep up with the amount of hydrogen atoms that join to form NADH, and cannot regenerate NAD+ quickly enough.)
  The resulting lactate can be used in two ways:
  Oxidation back to pyruvate by well-oxygenated muscle cells, heart cells, and brain cells
  Pyruvate is then directly used to fuel the Krebs cycle
  Conversion to glucose via gluconeogenesis in the liver and release back into circulation; see Cori cycle
  If blood glucose concentrations are high, the glucose can be used to build up the liver's glycogen stores.

Also, lactic acid is eventually converted back to pyruvate through Cori cycle. How is that pyruvate used?

In cori cycle lactate is finally converted to glucose via intermediate- pyruvate.

In response to comments , relation between glycolysis and fermentation:
Comment: I think it would be nice if you add this picture: https://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookGlyc.html (scrol a little bit down) , a nice graphical relation between glycolysis and fermentation
Comment: I didn't mean that figure, I meant the 3th figure @David
Comment: @RickBeeloo Is it correct now?
Comment: yes this will show the relatedness between fermentation and the need of NAD+ in glycolysis


Amalanadhipiran

Question: Which Alwar is called as Amaladhipiran? How many hymns has he composed in nalayira divya prabandham? On which God he has sung the hymns? I came to know that God himself told the priest to carry this alwar on his shoulders as the former had thrown stone and blood started pouring from latter's head. Finally he merged with God's feet as a jyothi.
Answer: The Alwar you are referring to is Thiruppan Alwar, who was an incarnation of Vishnu's Srivatsa mark as I discuss in my question here.  He has composed exactly one poem in the Naalayira Divya Prabandham.  As you alluded to, he was carried into the Sri Rangam temple by Loka Saranga Muni, where upon seeing the Ranganatha statue (which I discuss here) he spontaneously composed a 10-verse poem called Amalanadipiran, which you can listen to here.  Here is the meaning:

The perfect-first-Lord is the radiant king of the celestials and resident of Venkatam surrounded by fragrant groves. His golden rule is just and blemish less. He made me a slave of his devotees. He is the Lord of Arangam surrounded by lofty walls. O, his auspicious lotus feet have come to stay in my eyes!
With glee in his heart, he measured the Earth; his crown touched the roof of the Universe. He is the Kakuthstha Lord Rama, who rained arrows and killed the Rakshasas clan: He is the Lord of Arangam surrounded by fragrant groves. My mind hovers over the red vestures on his dark frame!
He stands in, the monkey forest of Venkatam hills over the North, worshipped by the celestials. He reclines on a serpent in Arangam. Over his sunset-red vesture, the beautiful lotus-seat of Brahma rises from his navel, obsessing my heart and spirit!
He shot arrows and felled the ten heads of Ravana, the king of fortified Lanka. He is the ocean-hued reclining in Arangam where peacocks dance to the song of bumble-bees. Aho; the cummerbund over his belly remains in my heart and haunts me.
Relieving me of my load of misdeeds, the Lord of Arangam made me his devotee; and what is more, he entered into me. What great penance did I do, I do not know. O, His' auspicious garland-chest has possessed me!
My Lord saved the crescent-crested Siva from sin. He swallowed, the world, the people, the space, the Earth, the seven mountains and all else. He resides in Arangam city surrounded by flower groves that hum with bees. O, see his neck elevates my spirits!
He wields the discus and conch in his hands. His body is like a dark mountain. He is my master with a tall crown wafting the fragrance of Tulasi. He is the wonder-Lord of Arangam reclining on a serpent bed. Aho, his red lips have won my heart over!
The first causes Lord, hard to reach even for the gods, the perfect Lord residing in Arangam, is the one who, tore into the tyrant Hiranya Kasipu's bowels. His face is set with dark wide red eyes. Aho, those eyes have made me intemperate.
He swallowed seven worlds and lay as a child on a fig leaf. He reclines on a serpent in Arangam. He wears a beautiful gem-set garland and a necklace of pearls on his dark frame. Aho, his matchless beauty has stolen my heart!
The dark-hued Lord is, the Lord who came as a cowherd-lad and stole buffer, He is the Lord of gods, and the Lord of Arangam also. He has stolen my heart. After seeing my Lord of ambrosial delight, my eyes will see naught else.
Comment: It's funny that this question was asked today given that I was thinking about this around the time it was posted. BTW is Thiruvenkatam the only other Divya Desa mentioned by Thirupaan azhvar or is there some other hidden one(s)?
Comment: @Surya I think Sri Rangam and Tirupati are the only two, unless I'm missing something.
Comment: @Both--Srirangam is the correct place. Thirupan alwar belonged to a lower caste and sung Lord Ranganatha. Fortunately I belong to srirangam. Born and brought up but now in chennai
Comment: @Parthasarathy Yeah, Sri Rangam is definitely the correct place.  Surya and I were just discussing whether there are also references to other Divya Desams within the poem.  There are several references to Tirupati, for instance.
Comment: @KS - Thirupan alwar will sing from kollidam karai about Lord Ranganatha and the Lord likes his hymns. It is srirangam only.
Comment: @ParthasarathyRaghavan Well, he does say things like "resident of Venkatam", so in that sense he is also referencing another Divya Desam in the poem.
Comment: @KS - To my knowledge he is so poor and resided in Uraiyur in Trichy. He was having an instrument made of bamboo which is known as Paan. He will sing song by operating this Paan. Hence he is known as paanalwar. Give me a day's time-- will refer the nalayira divya prabandam   special meaning  for all hymns to clear your doubt pertaining to thiruvengadam.
Comment: I think, tiruppan alwar is saying that the Lord of Venkatam is also the Same Lord of Arangam.
Comment: @Krishna Yes, of course Thiruppan Alwar is praising Vishnu in general.  Surya was just asking what Divya Desams other than Sri Rangam are alluded to in the poem.
Comment: @both tomorow will refer and reply to your question as thiruppan alwar has composed only 10 hymns in 4000 DP.
Answer: Amalanathipiran - Thaniyan

ThiruppaaN Azhwaar composed ten paasurams among the divya prabandham revered as "Amalanaadhipiraan" Prabhandham. All 10 pasurams praise our Arangan. As ThiruppaaN Azhwaar has not sung on any other divya desa perumal, Arangan gets the distinction of being sung by 11 Aazhwars.
This Azhwaar's prabhandham is different from all the other aazhwaar's
  prabhandhams in that it does not contain any upadesams, critique of Veda-
  Baahya Mathams, messages sent to the Lord as His Naayaki et al.
  Thiruppaanar's prabhandham is an aanandha-lahari (limitless outpourings of the
  bliss of aanandham) at the anubhavam of the Lord's Sarvaanga Soundharyam
  and its redeeming effect. Azhwaar is totally lost in that blissful anubhavam
  and the ten paasurams arose from him as "the revelational hymns".
Let me contemplate on TiruppaanaAzhwar (Munivahana, the saint who was
  carried to the precincts of the shrine of Lord Ranganatha, by
  Lokasarangamamuni on his shoulders), whose inner soul (antaratma) became
  enraptured at the sight of the reclining Lord Hari (Ranganatha) betwixt (the
  two streams of) the river Kaveri, and who, having experienced (the vision of
  the Lord) from the feet to His head declared that his eyes would not see any
  other objects (except the Lord).
Let us sing in praise of the holy feet of Sri ThiruppaanaAzhwar, who entered
  (the holy shrine of Lord Ranganatha) riding on the shoulders of the sage
  (Lokasaranga-Mahamuni) saw(the Lord in full) and sung (in praise) HIM limb by
  limb, as the Lord showed to him, i. e., the lotus feet, the silk garment, the
  navel, the waist band of rare excellence, the holy chest, the neck, the red
  mouth (with rosy lips), the eyes of unfading (red lotus charm) and the (whole
  divine) Archa form.

ThiruppaaN Azhwaar ThiruvadigaLE SaraNam.

Thirupanlawar has composed 10 verses on the lord of srirangam and thiruvengadam. if we take the first letter of the first verse "Amalanadhi piran adiyar ..", first letter of the second verse " uvanda ulaathinay ......" and first letter of third verse " Mandi Pai Vada ... " , it means aum or pranvam. similarly if we were to take the first letter of fifth pasuram "Paramaya Pazhavinay ..." , first letter of sixth pasuram "Thunda Ven Pirayaan .. " and also the first letter of seventh pasuram " Kaiyinar Suri Sanga ..... " it means Padhuka .
  Source --- Nalayira divya Prabandham

Amalanadhipiran


KVM/QEMU emulation of processor virtualization features

Question: I'm finding the developer documentation of KVM/QEMU to be weak/nonexistent and cannot actually find the answer to this question anywhere, does KVM/QEMU or any other virtualization product yet support emulating the AMD-V or VT-x processor features?
Answer: IIRC KVM has been able to do nested virtualization for a while on AMD and only recently on Intel processors. Better ask this on the kvm mailing list.
Answer: I discovered the answer. The term as one guy said was "nested virtualization". For kvm/kqemu pass the parameter -enable-nesting. Currently only amd is supported though.  Now my problem is that it still does not allow xen to run as a hypervisor because xen crashes ion boot.
Answer: Wind River Simics can provide a virtual machine with full VT-x support, from Simics 4.6.  I know it can run Xen, as well the Wind River Hypervisor, on a fully virtual x86 target.


Acid neutralization

Question: I am working on a biogas plant,
digester volume 3000 liter,
right now pH condition is acidic at 4.00
my requirement is to maintain pH to 6.50 to 7.20
what should I do?
some suggestions are there like, add NaOH or CaCo3
but I am confused about the how much amount should I add to increase pH
Comment: There has to be information on web about biogas digesters. What kind of gunk are you even digesting? // Off the top of my head I'd think adding anything willy nilly to the digester would be tedious at best. Seems like you need to take a sample, treat that, and then use sample size to scale up additions. // Part of the problem here is $\ce{Na+}$. I'd suspect that microbes aren't going to like high $\ce{Na+}$ concentrations from NaOH or NaHCO3. So you need a biofriendly base.
Answer: Add a base (whichever is suitable for your application) and then use pH paper (eg. https://www.coleparmer.in/i/hach-ph-strips-ph-paper-test-strips-0-to-14-ph-range-100-strips-pk/0554642) to test the pH in a sample of a specific volume of the mixture. Keep adding base (keeping track of the total amount added) and measuring the pH using pH paper until you are in the desired pH range. Just be careful not to add too much base and end up at higher pH than you need. Also make sure to give enough time to the solution to stir after each base addition before testing the pH. Once done, scale the amount of base used to the total volume in the digester. Ideally i would use an inline pH meter to continuously monitor the pH if possible (could contact mettler toledo who has really good quality products but wont be cheap, eg https://www.mt.com/int/en/home/products/Process-Analytics/pH-probe.html).
It seems that here: https://www.biogasworld.com/biogas-plant-monitoring/ a procedure is described that addresses your question where the ratio of volatile organic acids to alkaline buffer capacity is determined and therefore the risk of acidification of a biogas plant.
Comment: **Down voted -** Doubt NaOH is good for a biodigester. Need to take a sample and scale up. It doesn't seem that pH paper strips would work. Not sure if there are any specialty strips that would let you measure pH to 6.50 to 7.20 accurately.
Comment: @MaxW The question was to maintain the pH in the specified (broad) range and how to monitor the pH, not which base to add (actually NaOH was the OP suggestion and i used it as an example of a base, hence said 'say NaOH'). I assume it is obvious that he needs to sample and scale up (it is 3000 L after all).  Here are the strips: https://www.coleparmer.in/i/hach-ph-strips-ph-paper-test-strips-0-to-14-ph-range-100-strips-pk/0554642, they measure within 1 unit. Alternatively a simple pH meter can also be used. Also, 6.50 to 7.20 is not accurate, it is a range. Thank you for the comment i ll edit.

Acid neutralization