Where is Angle Measure Tool in ArcMap?

Question: Where is the Angle Measure Tool in ArcMap 10?
I can't seem to find it.
Comment: http://forums.arcgis.com/threads/15605-Angle-Measure-Tool-in-Version-10
Comment: There was a Measure/Angle tool written by Trent Hare of the USGS and modified by the Maine DEP.  It was a simple dll and was stated as usable in 8 and 9x.  I still use it in 10.4.1.  I could not locate a downloadable version in a few minutes of searching the Internet; perhaps others can.  I still have the one I got from the old Arcscripts site many years ago.
Answer: In ArcGIS 10.1 and later, there is a tool called COGO - located in the Editor Toolbar/More Editing Tools/COGO. On the tool bar there is a button called Reporting COGO descriptions. This reporting tool has a feature called "Angle between two lines" which reports the angle between 3 points on a line.
Answer:
Do you mean this?
Select, and then tap in angle, as per what u did in 931?
Can still do direction/length in combo as well.
Let me know if this is not what ur after
Answer: This Python script tool will do the trick. To use it, add it as a script tool, set the parameter to Feature Set - and set its schema to a line feature class. This script should work with 10.0 and later.
<code># calculate an azimuth angle from a interactively entered
# line (feature set)
#
# Curtis Price, firstname.lastname@example.com,  9/18/2013 11:51:10 AM

import math
import arcpy

# read line (This parameter should be a line feature set)
line = arcpy.GetParameterAsText(0)

# to see how this is used, see the help:
# http://resources.arcgis.com/en/help/main/10.1/index.html#//001500000028000000
# http://resources.arcgis.com/en/help/main/10.1/index.html#//002w00000023000000

def get_angle(xy1, xy2):
  """Calculate azimuth angle from two points. (Zero is north.)"""
  import math
  try:
    # ArcPy point objects
    x1, y1, x2, y2 = xy1.X, xy1.Y, xy2.X, xy2.Y
  except:
    # xy strings, e.g. "0 0"
    x1, y1 = [float(x) for x in xy1.split()]
    x2, y2 = [float(x) for x in xy2.split()]
  dx, dy = (x2 - x1, y2 - y1)
  return 90 - math.degrees(math.atan2(dy, dx))

try:
  # get first and last point of a line
  SHAPE = arcpy.Describe(line).shapeFieldName
  Rows = arcpy.SearchCursor(line,"","",SHAPE)
  feat = Rows.next().getValue(SHAPE)
  pt1 = feat.firstPoint
  pt2 = feat.lastPoint
  angle = get_angle(pt1, pt2)
  msg1 = "  First point: {0:.1f}, {0:.1f}".format(pt1.X, pt1.Y)
  msg2 = "  Last point:  {0:.1f}, {0:.1f}".format(pt2.X, pt2.Y)
  msg3 = "  Azimuth angle (in degrees): {0:.1f}".format(angle)
  arcpy.AddMessage("{0}\n{1}\n{2}".format(msg1, msg2, msg3))
except:
  raise Exception, "Invalid line input"
</code>
Comment: This answer gives negative values on the fourth quadrant (X and Y are both negative).
Answer: Without even being sarcastic, for most tasks I use a simple set square / triangle and measure directly on the screen. Quick and dirty solution that works just fine.
Answer: Clarifies @TvsGIS' answer. In ArcMap 10.3 use COGO toolbar, select COGO Report (7th button from left) then select "COGO description of an existing feature" (2nd from right : arrow pointing to middle of a line). Then click on line feature. This gives the angle and length in Grid (Map) and Ground (survey measurements) co-ordinates. The transform from Grid to ground is the ADD Direction Offset and divide by Distance Factor of Editing Options > Units > dialog.
If you use "Direction and Distance of a line" (1st button on left), then interactively select start and end points of the line. The angle is from your start point to your end-point. However the line segment may be draw in the opposite direction.
Answer: To measure an azimuth from a point with just Basic license you can use feature editing tools:

Create a dummy shape file with linear features
Start editing session
Select "Line Tool" to start creating new feature
Left click on point you want to measure your azimuth from
Right click on the point you want to measure azimuth to (the context pop-up menu will pop up)
Select "Direction..." option
The edit box where you are supposed to put in the direction will have the current azimuth.
Answer: With Add Geometry Attributes in the Data Management\Features toolbox - you can create a Line Bearing -Adds an attribute to store the start-to-end bearing of each line feature. Values range from 0 to 360, with 0 meaning north, 90 east, 180 south, 270 west, and so on.

Where is Angle Measure Tool in ArcMap?


How can a 3 years old understand and use the words "because" and "why"?

Question: I recently tried to explain to my daughter (3 years old) that she was crying a lot because she was exhausted. The reason she was so tired was because she did not sleep after lunch. When asking her why she sang rather than trying to sleep, she told me "I did not sleep because I cry a lot". Obviously she does not understand the words because and why (not that I am surprised given her age). But, how can I explain these words to her? Or how can I ask my questions another way so she can give me relevant answers?
Comment: To me, that sounds like she *does* understand "because". At 3, it's not reasonable to expect her to understand that her lack of sleep after lunch is why she is so tired now. All she knows is that now it is bedtime, but she is crying. That is why she did not sleep: because she was crying instead of sleeping.
Comment: Sometimes the cause and reason are simply transposed: my 3-year-old is currently screaming "too much jelly because I don't like it!" when trying to express the reason his sandwich is not satisfactory.
Comment: I've found that asking a 3yo "why" they do anything is not going to get good results.  It's not the language that's the problem, its them actually knowing (or not knowing, rather) their motivations for doing anything, especially if you wait and ask them after the activity is over.
Comment: @Justin `All she knows is that now it is bedtime, but she is crying. That is why she did not sleep: because she was crying instead of sleeping.` Not at all; she was not crying when it's bedtime. But you're probably right that it's not reasonable to expect her to understand the reason she is tired.
Comment: @JPhi1618 I'm probably expecting her to understand something too complicated for her age, as you and Justin point out. Thanks.
Comment: Well, don't stop expecting too much.  They will pleasantly surprise you quite often!
Answer: She understands the words just fine, what she doesn't understand is the underlying cause.  Kids that age live very much in the moment.  Past and present get jumbled in their mind, and they don't pause to reflect on their motivation.
Somehow parents can't resist asking why anyway, but I can count on one hand the number of times I've received an answer that makes sense to me.  Just resign yourself to it being the parent's job to figure out why, and if you're lucky, your kids will confirm it for you.
Comment: "That requires abstract reasoning skills that they don't really develop until puberty or so." A source for this claim (and why puberty?) would be much appreciated, in light of the claims made.
Comment: @anongoodnurse: An example from a psychology 101 course: "Put your coat on because it is cold outside". Apparently doesn't make any sense to a very young child because it is one level too complex, and suddenly around age three they get it. Obviously a long time before puberty.
Comment: @gnasher729 - I agree that they have abstract reasoning, as well as an understanding of right, wrong, and potential pain to others at three years of age, and this very age-dependent acquisition has been researched and proven in order to evaluate the ability of children to testify as witnesses in criminal cases. Frankly, the OP's claims seems to be simple anecdote. Hence the request for sources. "Past and present get jumbled in their mind, and they don't pause to reflect on their motivation." To use anecdote to answer a question is unfortunately common.
Answer: You can explain the difference (if you must explain it) by saying Why asks the question and Because tells the answer.


From design point of view, what are the purpose of these vertical lines on iMac G3?

Question:
Why they add these vertical lines on the machine? I don't think it is just for fun, it must be have some meaning to add this. I don't think a designer will ignore the details, and also it is in the keyboard too.
Answer: Why can't aesthetics be enough of an answer? There isn't any physical depth there. It's all smooth plastic. The lines are merely for visual interest. Pinstripe patterns have always lent a traditional aire of elegance to many things. They serve to break up a wide field of color - if the plastic were merely white, there's no interest. If it were merely grey it would appear drab. The variation creates elegance and a sense of motion or interest while at the same time not appearing too bright or too dark.
If anything the vertical lines would help the screen seem larger by counter-acting the ever-present horizontal lines which would appear on the screen itself (text, menus, etc.).
Now.. don't ask about the round mouse..... that was a stumble in usability :)
Comment: but is it the answer.
Answer: Just as on a woman's dress, vertical lines will make her look thinner, here they make the computer look a little sleeker.
Answer: My guesses:
-to show there is more to it...so ton of untouchable thin lines always remind more inside.
-As scott said make screen to be bigger by being part of something bigger.
-Highrises?
Answer: The iMac G3 was the first model of the iMac line of personal computers made by Apple. So we are talking about the first personal mac, and unlike the first PCs (integrated circuits, metal, thick plastic, I'm not really sure to be honest) it was made with beautiful brightly colored, translucent plastic.
I'd therefore agree with Scott: The reason is aesthetics. Something familiar for Apple, well known for bringing nice materials and carefully designed shapes (and software) to the table.


Is it possible to control the direction during auto-rotation?

Question: Is it possible to control the direction during auto-rotation, and how does it work?
Comment: If you forget the fact that you are only ever going to go down (ignoring that in some types you might be able to go up for a short time) many helicopters are delightful to fly in autorotation.  You can fly forwards, descend straight down (0 kts) or even fly backwards - although most pilots find the latter really uncomfortable.
Answer: It's entirely possible.
Attitude control works the same way during autorotation as it does during normal powered flight. It's a good thing, too... during an autorotation you want to target your descent toward a suitable landing spot :-)
To (say) roll right, moving the cyclic causes the swashplate to move in such a way that the rotor blade's pitch (angle of attack) is greater during the left-side portion of the blade's travel, and lower during the right-side portion. This produces more lift on the left side, which causes a right-rolling moment on the helicopter.
The fact that the collective is all the way down and that the rotor's RPM is being maintained by airflow through the rotor does not change the way the cyclic produces attitude changes.
The anti-torque pedals still work too, although during an autorotation the pilot will promptly apply full right pedal, since lowering the collective will essentially eliminate torque from the rotor. Pedals can still be used for yaw though, as the tail rotor is still spinning (it is linked to the main rotor).
The "180° turning autorotation" is a common maneuver taught in basic training, where the pilot must set up the autorotative descent and then complete a 180° turn toward a landing spot.
For more information about autorotations in general, I recommend the FAA's (free online) Helicopter Flying Handbook. See page 2-24 for a general description, and page 11-2 for procedures/technique.
There are also lots of autorotation demonstration videos on YouTube that show maneuvering to a landing spot / 180° turns during the auto.
Comment: @Hannes: Gyrocopter, better known as autogyro, _always autorotates_. It has normal rudder for directional control, which is sufficient, since autorotation produces very little torque.
Comment: Thanks, that sounds pretty exciting, especially the part about the tail rotor. Now, i'm asking myself, what would happen if i had no tail-rotor (i.e. i'm sitting in a gyrocopter), would i start to spin?
Comment: @JanHudec; I think "better known as" might depend a little bit on where you are. If I'm not mistaken, they're usually indeed called "gyrocopters" over here. Cool point about them always auto-rotating, never thought of it that way.
Comment: @falstro: The [wikipedia page](http://en.wikipedia.org/wiki/Autogyro) is titled Autogyro and mentions autorotation as defining feature in the first sentence.
Comment: `the pilot will promptly apply full right pedal,` depends of course on which way the top is spinning.  You've assumed counter-clockwise.  Doing that in a clockwise spinner will result in an underwear changing "unusual attitude".


What's the difference between a contradiction and a paradox?

Question: Why can't we just claim a paradox invalid, just as the way we treat contradiction in mathematical proof? (i.e. if we arrive at the proposition inconsistent with the assumption, then we can immediately claim the logical impossibility of the assumption).
Comment: I will add to Hunan answer only the *SEP* entry regarding [Paradoxes and Contemporary Logic](http://plato.stanford.edu/entries/paradoxes-contemporary-logic/).
Comment: Given that an argument usually relies on more than one assumption, the difficulty is to tease out which assumption is problematic.
Comment: Do you regard the Banach-Tarski paradox as a paradox? Why or why not? If not, then what is your definition of a paradox? If so, then are you claiming it should be "claimed invalid?" Which means what, exactly?
Comment: @user4894 No, the Banach-Tarski paradox isn't a paradox: it's just a surprising consequence of a particular set of axioms. Most "paradoxes" in maths and physics are of this form.
Answer: Paradoxes are indeed invalid arguments, but what makes them special is that they rest on seemingly unproblematic assumptions. We know, for example, that Achilles will in fact outrun the tortoise (Zeno's Paradoxes), we know that the surprise exam will take place (Surprise Exam Paradox), and so on. Because we know the conclusions of those paradoxes are false, we know that something is wrong with the arguments. The task then is to identify the assumptions that lead to the false conclusion.
Paradoxes can be called 'invalid' and ignored, but if taken seriously they can help us diagnose and fix problems with existing logico-mathematical frameworks. Axiomatic set theory and type theory owe much to Russell's Paradox, for example. The above mentioned Surprise Exam Paradox has led to lots of interesting developments in epistemic, dynamic, and public announcement logics. There are, of course, the classical ones, like the Sorites, the Liar, and so on. Each has opened some interesting door.
I claimed that paradoxes are invalid arguments. Sequitur's contribution inspired me to add that someone might ask: "invalid according to which logic?" I'd say classical bivalent first-order, but there are possibilities for significant 'paradox-preserving' deviations from that. What's important here is to realize that: you can't simply change the logic and claim that the paradox is resolved. Suppose classical logic C gives rise to paradox Π, but intuitionistic logic I does not. You cannot simply dispose of classical logic, adopt an intuitionistic one, and claim that you have handled the paradox. Even after doing that, fact will remain that Π is a paradox for C!, so one needs, if interested, to address why C enables the paradox.
Take paradoxes seriously, because they indicate that (at least) some thing is not as true as it seems.
Comment: Russel's paradox or the Cretan paradox are not in any way invalid arguments.  They are not even arguments.  They are single sentences that must be both true and false simultaneously in the logical systems in which they were proposed.
Comment: Hang on. Yes, we know that Achilles will in fact outrun the tortoise, but we do not know that this disposes of Zeno's argument. He was not arguing that we will never see Achilles outrun the tortoise, but that what we see is some sort of illusion, and that if we assume otherwise paradoxes will arise. He argues for a change to our ideas of time and motion, not that motion is impossible. It seems to me that paradoxes always depend on contradictions. That is, paradoxes are caused by contradictions and I'm not sure they can have any other cause.
Comment: @jobermark - Not sure about your point. Russell's paradox may not be an argument but it allows us to make a very good argument against the idea that the Universe can be modeled as the 'set of all sets', and this argument has extensive consequences in metaphysics. The physicist Paul Davies is good on this one, in his book 'Mind of God'.
Comment: @PeterJ Or it is a good argument for intermediate truth values in general. I favor intuitionism over ZFC. The point is that real paradoxes, in general, are not invalid arguments. They are not really contradictory and that is the problem. In order to even be contradictory, they require moving outside of the logical system into which they are proposed.
Comment: @jobermark - Metaphysical dilemmas such as One-Many arise because both horns give rise to contradictions. Thus we are left with what seems to be a paradox. So many arise that philosophers often claim that the world is paradoxical. I'd agree that these are not real paradoxes and that they can be solved by a proper use of logic, but you'll find it difficult to find a professor who agrees. Darn it, there's too many interesting discussions here to keep up.
Answer: Just to adress your question directly: We could treat paradoxes in the way suggested by you if the English predicates of truth and falsity were necessarily exclusive; that is if contradictions could not be true.
But whether this is so is a highly controversial issue. Proponents of weak paraconsistency say no, because (i) the English consequence relation is not explosive, i.e. contradictions do not entail everything (think of inconsistent fictions or theories, where apparently not everything holds) and (ii) consequence is truth preservation in all models (of a suitable non-classical logic) and (iii) models represent possibilities.
More boldly, propopnents of strong paraconsistency (aka dialetheism) hold that there actually are true contradictions and so true falsities are possible. Indeed dialetheists say that some paradoxes (such as the liar) are sound arguments. Non-trivial strong paraconsistency entails weak paraconsistency, but not the other way round.
If any of these positions can succeed depends on many intricate issues such as how best to treat paradoxes of self-reference (a strong justification for strong paraconsistency) and a quick settlement of the debate is not to be expected. So you're not justified in treating paradoxes by denying their validity.
Answer: A contradiction is something that cannot be true, because it refutes its premises.
In the strictest sense, a paradox is something that can be neither be true nor false, because refuting the premises provides an equally false set of premises.
Consider Russel's paradox: Does the collection of all collections that do not contain themselves contain itself?  The question cannot be answered 'yes' or 'no'.  Either answer implies the opposite.  If it contains itself, then it does not meet the criteria for being admitted to itself.  If it does not contain itself, then it does meet the criteria and must be included.
If you decide 'Russell's paradox is invalid.', what does that mean?  It can only mean that the answer to that question has some truth value like 'Irrelevant' which is different from both True and False.  This requires discarding the Law of the Excluded Middle -- because this falls flat into the 'middle' it is meant to 'exclude'.
This indicates that the basic naive intuitions involved in the statement are flawed.  These can be worked around technically, but cannot really be resolved.  Humans will still continue having the same flawed intuitions of logic and the paradox will continue to make a compelling case for the difficulty of reasoning correctly.
You can make up whatever special set of rules you want, but they will never be as compelling as naive logic, even though naive logic leads into plenty of paradoxes.
Comment: Agree about ordinary logic being more compelling than any other. But I'd rather say that naive logic appears to lead to paradoxes, and only appears to do so. Even Russell's paradox is not a paradox if we apply Aristotle's rules as he instructs.
Answer: To my understanding a paradox is a logical argument that fails because it is built on inconsistent axioms, e.g. a tower built on clay. In contrast, a fallacy is a logical argument that fails because of a faulty argumentation, e.g. a tower built without a plumb-line. A contradiction show that the axioms and the conclusion cannot be true simultaneously.
Comment: paradoxes don't necessarily fail.
Comment: point taken, by fail I meant 'leads to a contradiction'.


Detecting distance moved by accelerometer?

Question: I have an accelerometer connected to an Arduino Uno board, is there a way I can detect the distance it this accelerometer moved on each of the 3 axis?
Comment: No, not with any meaningful accuracy, as has been previously explained each of the many times this has been asked on the various stack exchange sites.
Comment: Check out the way I calculated the distance traveled by an elevator using the ADXL345. It's not the most accurate or even easy, but I go through the whole process on my blog: https://engineersportal.com/blog/2017/9/25/accelerometer-on-an-elevator Let me know if you have any questions!
Answer: This is normally referred to as Dead Reckoning.  The processes of determining position using known values, such as acceleration.
First we have to relate acceleration, velocity and position mathematically.  Velocity is the integral of acceleration with respect to time:

Similarly, position is the integral of velocity with respect to time:

Here is an explanation that should tie this all together.  However, it appears this explanation goes in the reverse order.  That is using derivatives of position to find velocity.  And derivatives of velocity to find acceleration.  Simply put, finding a derivative is the opposite process of finding an integral.
A final note, this all works well on paper.  In reality Dead Reckoning based only on acceleration does not work very well.  For instance, I believe most vehicle GPS systems tend to use steering and speed if Dead Reckoning is to be used for guidance.
Added later...
Found this web site where someone talks specifically about Dead Reckoning using an Arduino. He is simply using the deltas of filtered acceleration readings:
<code>velocity(i) = velocity(i-1) + acceleration (i)
position(i) = position (i-1) + velocity (i)
</code>
But goes on to say accumulated errors causes drift and positioning errors.
Comment: Comments are not for extended discussion; this conversation has been [moved to chat](http://chat.stackexchange.com/rooms/67364/discussion-on-answer-by-st2000-detecting-distance-moved-by-accelerometer).
Answer: Think about it:

Accelerometers measure acceleration.
Acceleration is a change in speed.
Distance travelled is speed multiplied by time.

If you know the starting speed (e.g., stationary) and you know how much you have accelerated between two points in time you can calculate the average speed for that time period - and since you know the time of that time period (one would hope) then you can get an approximation of the distance travelled in that axis.
I say approximation, because you are working with finite time points (quanta) and only looking at the acceleration at those points in time. It's far from perfect, but it can give you a rough ballpark figure. The smaller your quanta the better your accuracy - but it will never be anything more than a guestimation at best.
Now it's just, as they say, a SMOP.
Comment: Distance is the double integration of acceleration.
Comment: I downvoted this because it suggests you can get "an approximation" or "rough ballpark figure" when in reality you're not going to get anything useful out of this approach. The most important issue is that any inaccuracy in your acceleration measurement is going to blow up massively when you integrate to get position.
Comment: @TomvanderZanden I mentioned that it was a guestimation at best...  A guestimation, by the way, is worse than an estimation. An estimation is based on good data - a guestimation is based on guesswork, so is quadruply inaccurate. The link to SMOP is of course supposed to discourage the OP from taking this route since the programming would be outside his ability sphere.
Comment: @TomvanderZanden you still get usable figures depending on what precision you expect. And you can increase the quality using other sensors and filtering data. The dead reckoning technique can get extremely complicated, but the accelometric input is the base of most


Hover (question preview) box doesn't support TeX

Question: On my setup it appears as though the limited preview rectangle, which shows as a pop-up when the mouse hovers above a question and contains a text excerpt of the question's main text, doesn't support TeX. Is it supposed to work like that or is this a bug?
Answer: Yes, it's supposed to work like that. The hover effect is achieved by giving the  (link) tag a title property containing the excerpt, and then the tooltip is produced by the browser. There's no way (on SE's end anyway, the browser could theoretically be changed to do it) for this tooltip to support MathJax: the browser just reads the title attribute as plain text.
I guess it could be possible to modify everything to produce a tooltip with some Javascript and have this new tooltip be made to support MathJax, but frankly that sounds rather complicated for a small gain – you can just read the MathJax code to understand what's going on, and if you want to read more you can just click on the question. It would also cause the same problems as the search, where formulas are cut off in the middle and not rendered properly.
Comment: In principle it could be changed on SE's end by replacing standard title attributes by custom tooltips, like the one they use for Impact number in the profile and a few other fields. Those are regular `divs` that are made to appear on hover, and could be mathjax-processed as the rest.  Of course, one probably would not want to have randomly cut-off formulas rendered in weird ways, anyway.
Comment: @404 Well yes, maybe something like the tags. But honestly that sounds like a lot of complexity for a very small gain. Also this way even prehistoric browsers (and search engine crawlers, I guess) can read the title attribute.


help simplifying vector arithmetic

Question: I need to show that this matrix is orthogonal. I am not familiar enough with vector properties to simplify the right hand side of the equation.
$$
H = I - \frac{2}{xx^T}x^Tx
$$
where $I$ is the $n\times n$ identity matrix and the $^{T}$s all refer to transposes. Appreciate any help to get started.
Answer: We need to prove that $H^TH = I$.
$H^TH = (I-\frac{2}{xx^T}x^Tx)(I-\frac{2}{xx^T}x^Tx)
= (I-\frac{4}{xx^T}x^Tx + \frac{4}{(xx^T)^2}(x^Tx)(x^Tx))$
Now I guess x is a row vector. $(x^Tx)(x^Tx) = (x^T(xx^T)x)$ (by associativity of matrix multiplication) $= (xx^T)(x^Tx)$.
So $H^TH = (I-\frac{4}{xx^T}x^Tx + \frac{4}{(xx^T)^2}(xx^T)(x^Tx))
= (I-\frac{4}{xx^T}x^Tx + \frac{4}{(xx^T)}x^Tx)
= I$.
Answer: orthogonality means $H^TH = I$, right? We have
$$
  H^T = I^T - \frac 2{xx^T} (x^Tx)^T = I - \frac 2{xx^T}x^Tx = H
$$
so we have to show $H^2 = I$, it holds
\begin{align*}
  H^2 &= I^2 - \frac 4{xx^T}x^Tx + \frac 4{(xx^T)^2} x^Txx^Tx\\\
      &= I - \frac 4{xx^T}x^Tx + \frac 4{(xx^T)^2} x^T(xx^T)x\\\
      &= I - \frac 4{xx^T}x^Tx + \frac 4{xx^T}x^Tx\\\
      &= I.
\end{align*}
Answer: You mean $H=I-\frac{2}{v^T v} v v^T$, I presume, the Householder transformation.
To check for orthogonality, multiply by its transpose $H^T$. A quick check shows that $H=H^T$, so just compute $H H$ and show this is equal to the identity. So, in fact, it is orthonormal.
$$(I-\frac{2}{v^T v} v v^T)(I-\frac{2}{v^T v} v v^T) = I - 2 \frac{2}{v^T v} v v^T + \frac{4}{(v^T v)^2} v v^T v v^T$$
Since $v v^T v v^T = v v^T (v^T v)$, the right hand side reduces to $I$.
Answer: Following copper.hat I replace your $H$ by $H:=I-\frac{2}{v^T v} v v^T$; now the constant vector $v$ is a column vector. I claim that $H$ is the reflection on the orthogonal complement $U$ of the vector $v$.
Proof. When $u\in U$ then $(v\,v^T )u =v(v^T\, u)=0$, whence $Hu=u$, and when $x=\lambda v$ then $Hx=\lambda v-{2\over \|v\|^2}v(v^T\,\lambda v)=-\lambda v =-x$.
This immediately implies that $H$ is orthogonal.

help simplifying vector arithmetic


Wine made/handled by non-religious Jews

Question: Assume for the purposes of the question that all circumstances are the same as if the wine had been made/handled by non-Jews.  I don't want answers regarding whether it is Mevushal or whether Mevushal really helps or if it was opened or not opened, etc.  I am asking purely: Are the rules the same for non-religious Jews as they are for non-Jews with regard to making/handling wine?  If I cannot drink a bottle of wine because of the way/fact that it was made/handled by a non-Jew, am I prohibited from drinking that bottle if it was made/handled the same way by a non-religious Jew?
Comment: I'm not sure the footnote ('refrain from defining non-religious. Let's assume it is easily defined that the person in question is non-religious") is helpful. If, for example — and I don't know that this is the case — the _halacha_ depends on whether the person is a _mumar_, then a correct answer will have to mention that distinction, thereby violating your request that it "refrain from defining non-religious". Not that question as a whole isn't good (+1 from me), just that that footnote might need to be ignored when answering.
Comment: @msh210 Then the answer would be, "It depends on whether or not he is a Mumar." It could be that wine handled by anyone who violates Shabbath in public is a problem. That's not what I'm asking. I'm purely asking if the rule is exclusive to non-Jews because of Yein Nesach, or if it applies also to Jews under certain circumstances. If it's only if the Jew is a heretic outright and/or believes in a non-Jewish religion and might be suspected of actually using the wine for said religion, then that would also be a fine answer. But that = "it depends".
Comment: It would seem to me that if halacha requires us to distinguish between the haver -- one assumed to know the rules to take trumah, and therefore trustworthy -- and the am haaretz who we assume is ignorant of the laws of tithing and therefore is not trustworthy with other details, we would also be strict regarding wine.
Comment: I think you may mean non-observant. How "non" isn't really vital for the purposes of posing the question, I think.
Answer: According to Eretz Chemda, if he is a "Tinok shenishba", his wine would be kosher. If he isn't (he says he denies Hashem after he investigated the matter) and is Mechalel Shabbos in public (even in front of a Torah Scholar), his wine would be Yayin Nesech.
Answer: To add to Shmuel Brin's answer:
R' Moshe Feinstein rules that a Jew married to a non-Jew is presumed to not observe Shabbos, and R' Moshe implies that such a person would have the presumptive status of a public Shabbos violator. Accordingly, R' Moshe rules that non-mevushal wine such a person touches is forbidden (Igros Moshe YD vol. 2, §132).
R' Yosef Messas (Otzar HaMichtavim 2:1302, h/t @Maimonist) discusses a circumstance in which he rules that the wine of public Shabbos violators would be permitted:
Although R' Messas is generally lenient when it comes to the laws governing wine of non-Jews (such as to permit liquor made from non-Jewish wine, see Otzar HaMichtavim 1:454,462), he affirms that public Shabbos violators would generally render wine forbidden through contact.
However, after noting the abundance of Shabbos violators and the great degree to which the communal life of religious and partially religious (but Shabbos violating) Jews was intertwined,1 R' Messas makes an allowance for the wine. The reason he gives is that prohibiting the wine would be taken as a grave insult that would disrupt the great communal unity in their communities and instead create massive strife. He adds that prohibiting their wine would cause the Shabbos violating Jews to be resentful and totally abandon Judaism and any religious observance. He also mentions that provoking the animosity of the less observant Jews could lead to a severely damaging backlash against the Shabbos observant Jews.
R' Messas' would apparently extend this allowance to any community where treating the wine of Shabbos violators as prohibited would cause this sort of discord, as he mentions that one may actively countermand a rabbinic prohibition for the sake of avoiding strife.2

1 This responsum was sent in 1939 from Algeria (probably from the Jewish community of Tlemcen) to the Jewish community in Kenitra, Morocco.
2 One may actively countermand a rabbinic prohibition for the sake of kavod hab'riyos ("human dignity"; see, for example, B'rachos 19b). R' Messas rules that one may do the same in order to avoid strife, but the basis for this is less clear. R' Yehuda Segal (Tzemach Yehuda 3:59), for example, appears to rule that this allowance does not extend to actively overriding a rabbinic law to avoid strife: "וכבוד הבריות שנדחה היינו באם בזה גופא יש כבוד הבריות ולא שהוא יעשה מחלוקת ואיהו עיוות נפשיה". The Ritva (Shabbos 23b) says that peace and harmony alone allow one to use candles for lighting the home instead of lighting Chanuka candles (thus failing to perform a rabbinic obligation by default), but even the Ritva doesn't go so far as to say that one may actively violate a rabbinic law for peace.
On the other hand, the Sho'eil U'Meishiv (vol. 2, 3:106, "וגדול כבוד הבריות ובפרט בזמנינו קשה המחלוקת") might possibly be understood to halachically link the two. Likewise, it is possible that the Maharam miRothenburg may be understood to permit violating most rabbinic restrictions for the sake of peace (§758, where he upholds the rabbinic prohibition against annulling oaths made in HaShem's name even in the face of an impending divorce. It seems that his reasoning is that there was a particular exigency in upholding that rabbinic restriction - since people were being too flippant with oaths - that outweighed the special importance of fostering domestic harmony).
Comment: Sherkoyach. [hat tip] Kol tuv.
Answer: In order to avoid situations of mixed-marriages , which almost certainly lead to assimilation , the Rabbis enacted many decrees whose goal was to inhibit the forming of close relationships between Jews and non-Jews.  The laws of stam yeinam (wine that was produced or handled by Non-Jews) are included in these decrees.  On the other hand, the Torah, and in its footsteps, the Rabbis, wanted to encourage close relationships amongst Jews, and they therefore established that a single witness is believed regarding prohibitions.  The Yerushalmi  explains that this was done in order to enable Jews to conveniently eat and drink with their fellow Jews.
Let us therefore preface our response with some of the principles and basic laws regarding wine and when a non-Jew comes in contact with it, only afterwards will we deal with the issue of wine that comes in contact with a Jew.
Even if a non-Jew opens a bottle of wine, the contents are not prohibited .  If a non-Jew pours a cup of wine, according to many opinions, the wine is prohibited , while some opinions are lenient if a monetary loss, even a small one, is involved .  There is also a dispute regarding the permissibility of the wine that remains in the bottle .  Even those who are stringent will permit the wine if a large loss would otherwise be incurred .
All this is regarding natural wine, but cooked wine was never included in the prohibition .  There is a dispute amongst contemporary Rabbis if the pasteurization process renders the wine as cooked  or not , one can be lenient, since this is a doubt on a rabbinic prohibition.
Now we will explain the law regarding wine that was poured by a non-religious Jew .
If he would open a bottle of wine, the wine is certainly permitted, as was mentioned earlier regarding a non-Jew, all the more so when it is opened by a Jew.  If a non-religious Jew pours a cup of wine , if he is the type of Jew who does not fulfill the ritual commandments (bein adam LaMakom), since that is how he was educated and raised from a young age , then the wine does not become prohibited by his pouring or his touch.
However, if he declares about himself that he willingly is a non-believer as the result of his investigations and searches , and he publically violates Shabbat, meaning he violates Shabbat even in front of a great person , then he is considered as someone who is a heretic on the entire Torah , and the wine would be prohibited.
In any case where there is a doubt as to his status, one may be lenient, as is the case with every doubt on a rabbinic prohibition.
A full response in Hebrew with sources can be found Bemareh Habazak volume 7 siman 62:
http://eretzhemdah.org/data/uploadedfiles/ebooks/36-sfile.pdf
Answer: According to R' Moshe Feinstein this is just a chumrah which does not apply to most non-Shomer Shabbat Jews today.
As summarized by dinonline:

Some authorities rule that one can be lenient concerning the touch of wine by those who violate Shabbos publicly (see Iggros Moshe Orach Chaim 5:37).
The reason for this is that although the Shulchan Aruch (124:8) rules that wine touched by a mumar if forbidden (as emerges from Chulin 72), this is only because of a concern that the person is an idolater. Today's non-observant Jews are not idolaters, and there is no concern for idolatrous libations, so that the prohibition does not apply.

Wine made/handled by non-religious Jews


Search questions by last active date

Question: For the two badges Excavator and Archaeologist, you need to edit posts that are 6 months old (1 and 100), respectively. Of course, finding a random post that happens to be 6 months old is very difficult, so is there any way that you can search for a post that is a certain age?
Comment: https://stackoverflow.com/help/searching (Advanced Search options include date logic)
Answer: You can use the site search to find questions that were last active 6 months ago:

is:q lastactive:6m

and you can amend that with your favorite tag or other aspects.
Look at the Searching help for more options you can use to filter your resultset.
If you want to have even more control, consider SEDE or try one of the already existing queries found on MSE

Search questions by last active date


Why aren't user accounts that only post spam auto deleted?

Question: Reviewing my flagging history I saw that many user accounts that have posted only one message (a spam) are still alive. What's the point? Increase the SO user stats? Shouldn't they have been auto deleted from the system?
Comment: SO doesn't need to increase user stats; these accounts don't count as 'active' anyway. Yes, they should be autodeleted, eventually.
Comment: Creating a new account is ridiculously easy, by spammers and blocked users alike.  Which do you like better, a known spammer account or one where you have to figure it out all over again?
Comment: I think that an account who have post nothing more than a spam since says 90 days should be auto removed
Comment: The User account clean-up script doesn't run regularly and is known for having a backlog. See [this answer of mine for how that impact certain stats](http://meta.stackoverflow.com/questions/296967/what-is-the-median-reputation-level-on-stack-overflow/296970#296970)
Comment: the understanding I got from the answers to [this question](https://meta.stackoverflow.com/questions/295940/) was that account deletion is a manual process performed by moderators -- not an automatic one.
Comment: Also related: http://meta.stackexchange.com/questions/165311/auto-delete-destroy-1-rep-user-when-their-post-is-deleted-as-spam
Comment: @HansPassant figure out who have post nothing more than a spam since says 90 days should not be so hard to implement IMO  :)
Comment: _"Shouldn't they have been auto deleted from the system?"_ Assuming they aren't (eventually)...
Comment: Related: https://meta.stackoverflow.com/questions/275534/is-the-site-really-cleaning-up-1-rep-users-with-no-activity
Comment: the system seems to only remove account named userxxxxx ....
Comment: @BoltClock this post have some really interresting suggestions about fighting spam and spamers
Comment: inactive spam account seems no effect on me, if remove them has technical issue I prefer not touching them, to prevent extra workload of moderator
Comment: When I ask the same kind of question it's 11 downvotes where as yours 20 upvotes. Good bye earth. Going to planet pluto :P  http://meta.stackoverflow.com/questions/306457/cant-we-delete-directly-delete-vote-to-delete-before-closing-a-question
Comment: @amuse keeping useless data is power and data consuming ...
Comment: @sᴜʀᴇsʜᴀᴛᴛᴀ your question was about deleting questions more hastily, and was rather confusingly phrased. It also had no real mechanical limitation, implying that *all* questions would potentially be subject to this at the whim of delvoters. They are two quite different questions.
Answer: A while ago, I actually argued against something like this, but the reasons I gave there no longer apply. I had wanted these accounts to stick around long enough for us to use them to uncover other spammers at their IP address.
We now have other ways of doing this that don't require these accounts to hang around. Spammers are also less likely to come from the same location with relatively recent modifications to the intelligent spam-blocking system. There isn't as much of a need to keep them around for moderators to look at.
When moderators encounter accounts that only have one or two pure spam posts to their name, we almost always destroy them after we remove the spam posts. The ones that aren't deleted are typically the accounts that get posts destroyed by 6 community spam flags before we even notice them. That tends to happen when we're lightest on active moderators (night in the U.S.), so I'll tend to search back for these in the morning.
Keeping the accounts around generally doesn't do much, as they tend to be hard-blocked from posting after their initial post is destroyed as spam, but I've occasionally seen spammers revisit old accounts to use them to work around First Posts review. Most spammers tend to move on to new throwaway accounts at different locations once each has been spam-flagged.
As CRABOLO points out, many accounts like this are automatically deleted after six months.
Looking at things now, I think it makes sense to automatically delete an account immediately if the only post or posts they have made are all destroyed by either 6 community spam flags or 1 hard moderator spam flag. That would save us a little time, and maybe a little follow-on spam. This automatic deletion would not apply to an account that had any posts that were not destroyed in this manner, so as to avoid possibly removing any accounts that had any value or to avoid malicious coordination of spam flags.
Comment: I just facepalmed so hard I knocked myself out. Who do I sue?
Comment: @Will I think you sue yourself for damages, then collect from yourself in an out-of-court settlement. I'd recommend using the money to go get ice cream to make you feel better, and maybe a band-aid if there's any bruising or splitting.
Comment: Wow, gr8 topic you are wrting about (www.greatrussianwives.com). This is superbly best on market right now, and you (www.facepalm-pills-82.net) defiantely know the words to describe (www.shoesplusmarket99.com).


What is the best raiding strategy to get gold at townhall level 5?

Question: I am at level 5 Townhall, and I want to upgrade my walls.
I'm not good at raiding. Which would be the best troops to train to get gold?
Answer: All builds are different but in my opinion you should not be working on your walls at all at this time.  If you face any enemy that is strong enough to blow past your defenses (cannons, archer towers, etc), they will get past your walls.
 TIPS at Townhall Level 5
At this TH level, You should try and focus on farming & building.  I do not recommend going for trophies or otherwise known as cupping.  The more trophies you have, [99% of the time] the harder the opponent you are trying to farm from.
Try to max out your camps, barracks, and Clan Castle (which you also have to be in a clan) first so you can have the max number of troops to attack / farm with.  At TH level 5, these are the max building levels:

At townhall level 5, max level barracks is level 7, max level Army Camp is 5 and max level Clan Castle is 2.

Note the unlocked units at Barracks level 7.  The strongest unit you have is the Wizard, although you should factor in cost of elixir per attack.

As the picture above shows, you can have a max of 3 level 5 army camps which will hold a total of 135 troops.   Take the 135 troops + 15 troops from a full clan Castle (which again you must request from clan members) = 150 Total attacking troops.
The last factor you have to put into perspective is what league you are in.  My recommendation from average opponent strength would be these builds:
TL;DR
Trophies 0-1400

10 Giants (housing space of 5 each) = 50
50 Barbarians (housing space of 1 each) = 50
8 Wall breakers (housing space of 2 each) = 16
29 Archers (housing space of 1 each) = 29  OR 29 Goblins (housing space of 1 each)

Total of 150
If elixir and time is not a factor when farming, then a good tank & heavy DPS build should do the trick.

15 Giants = 75
10 Wall breakers = 20
12 Wizards (housing space of 4) = 48
2 Goblins/barbarians/archers = 2

Total of 150
Have your Giants be your tanks.  They will go for defenses first.  While the defenses are distracted by your tanks, try to attack their resources.
As I mentioned above, I do not recommend going for trophies.  Once you have the majority of your opponents resources, quit the attack by tapping the Surrender button.
The more gold you have, the more you should focus on protecting your resources for when you are not playing.  Therefore, I would advise putting your gold back into upgrading your defenses such as cannons, archer towers, etc.   Try not to upgrade your walls past level 5 as you should put those resources elsewhere.
Comment: I recently got all my walls to level 5
Answer: If you have level 7 barracks I would recommend using a archer/barbarian/goblin strategy with wizards to finish. Because your wizards may be lower level, I would suggest using only 3-5 of them. Another good thing is to use 4 giants as distraction from the mortars and using smaller troops to destroy everything else.
Answer: TH6 and now TH8 and all been using 12 giants, 6 wall breakers, 1 healer, 40 goblins and the rest archers. I have gotten so much loot that i run out of storage. especially elixir storage. this combo should yeild around 100k+ of gold and 100k+ of exilir. I have taken 400k of each and did not completely destroy their base. Again we are farming not pushing trophies. :)
Comment: How are you still using healers? I ruled them out once I got to near end lvl 7 townhall. They die too quickly and healing potions don't worry about air defense.
Comment: @BakedPotato First you have to take AD if all AD is distributed. If All AD are centralized don't use healer. You are attacking a base from one side only so from that side if any AD is there means take it out quickly and deploy healer.
Answer: TH5 - raiding with this method: 1 lightning spell, any 15 donated troops, 3 wall breakers,4 or 5 giants, 2 ballons, 2 or 3 wizards, 15 archers and the rest of them barbarians. You must have 3 upgraded army camps and 120 space. Your clan castle must be at level 2.
First, drop a lightning spell on mortar, drop 3 wall breakers near the wall close to the gold storage. Place your giants, and after that all of your barbarians and donated troops at the same time. Drop your archers anywhere you want - I suggest you drop them at elixir storages or gold mines. After that, you must drop your wizards and balloons. You surround the map with this. At the end you will win 1 or 2 stars and have stolen 80 percent of resources from your opponent. Good luck!
Answer: BALLOOONS BALLOOONS BALLOOONS :D I use 30 level 2 balloons for a camp space of 120. I totally destroy every land i pass by. But I don't attack those with a very high level of archer towers or those having their air defense in the middle or have two upgraded air defenses. Try to aim for those having their air defenses on the out side which makes it easier for balloons to destroy them at first.
Answer: Use

4/6 giants
3 wall breakers
60/80 goblins
20/30 barbarians
10/20 archers
Answer: Always get at least 6 giants, and tap them near the main defenses like wizard tower mortars because they are the strongest.
While they are attacking and distracting, then tap the goblins (the quickest and strongest at breaking) near the gold or elixir storage and take all the resources.
Go for trophies because you get bonuses when you're in a league.  For example, I'm in the master league, so I get 50,000 gold and elixir.


Can a friend put up collateral for my secured loan?

Question: I'm the friend. My mom needs a loan from me and figures involving a bank might avoid some headaches.
She wants me to lend her 20K. Wire it to the bank. Then the bank will (presumably) lend her 20K.
Do banks do this?
Comment: This is actually rather common; the loan becomes "secured" by the up-front payment, and the bank will thus lend at a lower rate. Contrasting with a direct gift, the lending person avoids taxes (an informal loan of money is considered a "gift" for tax purposes), and the lendee can build credit history by repaying the bank who reports to the credit agencies.
Comment: Regardless of which option you chose just assume that the money is gone. That way when you get the money back you can be happy. Don't say I don't need the money for x years, and also expect it to be the college fund.
Comment: I didn't understand the process, you give 20K to the bank as a collateral, and the bank lends this money to your mom? Why not just give the money to your mom directly?
Comment: I don't want to bother with micropayments, and harassing her for monthly payments.
Answer: Short answer: yes, you can put up collateral for someone else's loan. The bank will be happy to take your money, give it to the other person, and return it to you on completion of the loan (keeping the interest the security makes on the money market and the interest they're charging the other person for themselves).
If the above doesn't sound very appealing (you don't see any benefit from your investment, and can be left holding the bag if your friend defaults on their loan), it really isn't a great way to spend your money. However, as assistance to someone else, it provides several advantages over directly transferring the money:

The lendee gets a better rate than they normally would from the bank - Basically, from the bank's perspective, the loan's covered, so there's very little risk of a default leaving them holding the bag. As such, they can typically offer rock-bottom, cost-of-capital rates.
The lendee builds credit history - Since the lendee is making payments on a legitimate, structured loan to an entity that reports to the credit agencies, this is a very good way to help the lendee build good credit.
You avoid the gift tax - If you lend over $13k, unless there's a contract between the two of you stipulating a schedule of payments, it's a "gift" as far as the IRS is concerned and you will be taxed on the amount above the exemption.   EDIT: The $13k figure (going up to $14k for 2013) is only the limit if the loan is not a loan, but in fact treated as a gift (i.e. no reasonable prospect of repayment).  For bona fide loans, there is no fixed upper limit on the amount you can loan, but the gift tax will be determined based on the difference between the interest charged and the "applicable federal rate" (this rule is found in IRC Sec. 7872; check IRS.gov for monthly Rev. Proc.'s listing newest AFR's).  Last time I checked the short-term and medium-term rates were around 0.2%, so if this still holds it's an excellent time right now to "gift" your credit at little to no gift tax cost.  One can even take advantage of this by making so-called "back-to-back" loans- taking out a HELOC at 4% and subsequently loaning proceeds to your child at .2% (or whatever the current AFR), producing no taxable gift on the 3.8% difference.
The lendee may be able to deduct interest - depending on the type of loan (maybe the $20k is the 15% of an 80-15-5 mortgage), the interest paid on that loan can be tax-deductible. A personal loan between friends? No way.
Comment: Yep. That's the risk. If your mom defaults on the loan, the bank will take any unpaid principal, interest and fees out of the collateral amount and *may* return the rest to you (or they may keep all of it as a penalty), hanging you out to dry. It's a tax write-off, but for you that would probably be a consolation; if you make $50k after deductions, now you made $35k (you can either take your $5k standard deduction or itemize the $20k. but not both), so you'd get between $3k and $4k off your tax bill. You'd have to sue your own mother for the rest, and she could demand a jury trial.
Comment: I just don't understand this process and why this is being considered at all.  The OP gives $20K, say, to a bank which turns around and makes a loan to Mom and charges her interest (which the bank keeps). At the end of the process (say in 5 years), the OP gets $20K back from the bank if Mom successfully makes all the required payments, less if she defaults. Mom has to make monthly payments, and gets hassled if she is late in making a payment. She also gets a _bad_ credit history if she defaults or misses payments. I see only down sides, but the OP has accepted the answer (without an upvote).
Comment: I told you that it wasn't an extremely appealing option in terms of risk/reward. But, my father-in-law did pretty much the same thing to secure a car note for my wife; basically my grandparents sold her the car for $3k since they couldn't drive it, my FIL secured that loan with cash, and she paid it back at next to nothing through the bank while building good credit on the loan. There are advantages to doing it this way versus keeping it under the table, as stated in my post; virtually none of them benefit the OP directly, but I fail to see how your solution would be any better for the OP
Comment: However, I fail to see how your solution would be any better for the OP than this. You're advocating that the OP not only give the money to his mother under a relatively lax "contract", but also *pay her* the amount of the interest, with the under-the-table arrangement that she then pay it back to him, thus making the huge gift look like a loan and keeping smaller gifts under the exemption. The IRS would recognize this as blatant tax evasion, there's zero incentive to pay it back except guilt, and the only method of enforcement is for the OP to sue his own mother.
Comment: @DilipSarwate (the OP has insufficient rep to upvote, but can mark an answer as accepted.)
Comment: @KeithS Nothing of what I said is tax evasion, blatant or otehrwise, and there is nothing for the IRS to recognize. The loan charges full interest at a rate that the IRS finds acceptable, interest is paid annually by mom (and reported as income by son), and son makes annual gifts to mom in amounts not exceeding $13K and so no gift tax return is required. There is **nothing** that is under the table in all this: everything is on the up and up. Simply forgiving the interest each year and counting it as a gift is also possible, but a paper trail of money going both ways is better.
Comment: @KeithS It is obvious that we disagree on this matter. You find little merit in my suggestions, and I find little in yours. It is best that we not snipe at each other any more.
Comment: I agree with KeithS answer, although we don't know what OP wants, maybe he wants his money back from Mom. However if he creates a loan, and ask's mom to pay monthly ... the chances are more she will default more to son [she is in position to make any escuse and he can't say no] ... than her defaulting on Bank plus other benefits of building credit history. Dilip's answer also makes sense, why involve bank when one can settle a family matter, the risk is same either ways ... however we still don't know OP's real concern
Answer: There is no need for micropayments, monthly payments, or harassment.
A loan agreement can be drafted that your mom makes one payment annually to you
instead of monthly payments. Depending on what she (and you) might be comfortable
with, this payment could be interest only, or partly interest and part repayment
of principal.  Or you can set it up so that there is a balloon payment due when
the loan terminates (say in five years' time) and she pays back the entire
principal and accumulated interest. If you trust her to pay back the money,
you don't need to ask for collateral or security, and you don't need to
turn the debt over to a collection agency or send large men with
baseball bats to call on Mom.
If you just want mom to return the principal when she is ready to so so,
and don't really want to charge her interest, then set up the loan to
require annual payment of interest only (and the entire principal at
the end of the agreement). Then, each year, a few days before the
interest payment is due, send her a check for the interest
due as a gift.  Mom deposits the check in her account and sends
back the interest payment to you. So, no harm, no foul: you have
made her a gift (presumably less than the $13K exemption), she has
paid you interest, but there is no net transfer of money, and
as far as the IRS zebras are concerned, this is a legitimate loan.
Do keep copies of the paperwork, though, and be sure to report
the interest payment on your income tax returns as income to you.
By extension, if you don't really want the money back, set up
the loan so that the annual payment is $13K and is part the
annual interest due and part the principal until the loan is paid off.
Comment: One should not loan mom money. She gave you life, you should give her $13,000/yr with no strings attached.
Comment: Only one question; if the OP's mom defaults on this agreement (which is already extremely disadvantageous; he's loaning a large sum of money and then paying *her* the interest on it so she can pay it back), is he going to sue his own mother for strict performance of the contract? If the bank is requiring the loan to be fully secured in order to even make it, then I think his mother would benefit more from building credit by paying the bank, and she sounds like a HUGE default risk.
Comment: @JoeTaxpayer While I agree with your sentiments, that does not seem to be something that the OP wants to do, and I didn't want to be in a position to be be preaching at him (cf. a recent discussion on meta.money.SE).
Comment: I'm sorry. I meant this tongue-in-cheek. I +1 you, your answer was spot on.
Answer: Since this is the reasoning:

I don't want to bother with micropayments, and harassing her for
  monthly payments.

You must do one the following:

Provide the money to your mom as a loan (i.e.: with a note and interest) payable when the full repayment of the loan to the bank is done (i.e.: balloon note). The terms of the note should be that the money to be used as collateral for the secured loan from the bank.
Provide the money to your mom directly. In this case you have to pay gift tax on $7K (above the 13K exemption limit).

Since you want the money back - you'll probably want the option #1. Your interest rate should be above a certain level to avoid reclassifying it as a gift by the IRS (your tax adviser can help you with that). Your mom will pay interest to the bank on the secured loan, and to you on the collateral (unless you wave it, subject to gift tax, again - talk to the tax adviser). You will only need to harass your mom about the balloon payment in the end.
This is not a tax or legal advice. Talk to your tax adviser and a legal counsel about the details and additional options.
Comment: Actually, gift tax does not have to be _paid_ on the $7K if one is willing to reduce the lifetime combined gift and estate tax exclusion (currently $5M or so, scheduled to go down to $1M or so unless Congress does something) by $7K.
Comment: Dilip - well done. Exactly.
Comment: For (2) you mean not as loan? So long as the loan is legitimate, there's no gift tax.
Comment: Yes, (2) is not a loan, its a gift.
Answer:
I don't want to bother with micropayments, and harassing her for
  monthly payments.

Alternative approach to lending her $20K, arranging for her to pay you back $x per month, and having to (as you say) harass her for micropayments.
Instead, you give her the $20K, and she sets up a savings account with a monthly direct debit deposit of $x. The bank takes care of the monthly "payments" into the savings account, and at the end of the loan period, you've got your $20K, and instead of the bank making interest off your mom, you make some interest out of the savings account.
Comment: Interesting approach; setting up direct deposits through the bank would give a similar level of impersonal abstraction that the OP appears to want. Neither one would need to mention the payments to eachother, and it would encourage strict adherence to the policy. The one downside would be that it would remove the potential penalties that would apply should the mother not pay on time. Some would see this as a benefit, but if the OP is concerned about their mother not taking this seriously, then it remove the element they are looking for.


Permission level to edit My Regional Setting

Question: I want to set a permission level for a group of users only to be able to change the My Regional Setting. I have made a custom permission level with the "Edit Personal User Information" check on. They still get an access denied. They have only access to some lists and limited to root. What should they have more for permissions?
Comment: Do you want to change the "Regional Settings" which comes under the Site Administration section on site settings page or My sites regional settings...??
Comment: "My Regional Setting". Like already said in my post...
Answer: See the question wasnt clear enough . Are you attempting to change regional settings on Web Application level or site collection level ?
Do you want to change regional settings for team sites or mysite ?
One thing is for sure , if you want to change regional settings in list/libraries that cannot be done because they follow Site collection level permissions for editing regional settings.
You need to be site collection administrator if you want to do that.
Let me know if any doubts !!
Comment: On site level, the My Regional Setting through My Settings of the users profile.
Comment: okay so you want to change regional setting for particular users right ?
Comment: If you want to edit on my site of a user , you need to go to the mysites page of user by clicking on the user name . In the edit details in the language and region you need to change the option for regional setting to always use my regional settings otherwise it will inherit from site collection.  For this you need to have permission on user profile service application to modify user profiles . Let me know if this is  not clear
Answer: Found out that you also need the "View Pages" Permission Level.


How do hiring committees for research positions view getting "scooped"?

Question: Suppose that an applicant got scooped on a research paper and is applying for jobs. This is reflected in a lack of publications. Is that taken into consideration? Or will it be a huge blow to an applicant's chances to highly competitive jobs?
Comment: You can always go to eastern Europe and become ghostwriter out of spite. ;)
Comment: @mathreadler Ghostwriters exist and are doing well in the US and western Europe, too. This problem knows no boundaries.
Comment: @user4052054 There is no problem with eastern Europe. It's nicer than ever. :) You can get more beer for your money, new exciting languages, cool old cities et.c.
Comment: @DmitrySavostyanov of course, but there would be no impact in the face of just staying and doing that.
Comment: @mathreadler What's the problem with eastern Europe?
Answer: I'm a little surprised by the implicit assumption that "scooped" ==> "no paper whatsoever."
It's often possible--and desirable--to publish the scooped work anyway. It might have less impact than it otherwise would have, but it's miles better than nothing. Furthermore, it's unlikely that both papers tackle the problem exactly the same way; highlight those differences in your revised version. If nothing else, replications are increasingly appreciated. This is especially true in trendy areas, where both scooping and dubious, non-replicable results are most likely.
It would be gauche for you to complain about this directly on your cover letter or CV (how would this even work?!). With a publication, however, your references can write:

"Grad Student's main project, characterizing the properties of
  l-Phlebotinum and d-Phlebotinum, was just accepted at the Journal of
  Decent Results. Although his thesis committee praised the work as a
  technical tour de force, it unfortunately attracted less attention
  than it might have after Evil et al. (2018) published similar
  results last December in Science."

Obviously, you'd prefer not to get scooped, but this does demonstrate that you're working on 'hot' problems that people do find interesting, which is better than nothing.
Comment: I like that Dr. Evil and friends publish in *Science*, while the good guy publishes in *Journal of Decent Results*.
Comment: I once got "scooped" while I was in grad school. I referenced the work that came out while I was in progress, modified mine slightly to make sure it emphasized the differences in my work on the others, and got mine published as well. Admittedly, my field (law) may be more amenable to pivots than an experimental field, but in an experimental field it is also far less likely that one researcher's experiment exactly duplicates another researcher's so it should still be possible to emphasize the differences and publish if the question being tackles is genuinely deep.
Comment: @CliffAB, just telling it how it is :-)
Answer: They might empathize if you somehow decide to mention it somewhere in your CV/cover letter/research statement/whatever. But in the end, you will be judged based on what you have actually produced. "Getting scooped" is difficult to verify if you have no publications. It's easy to say "I was totally going to say that!" when someone else says something clever. It's another thing to do the research well, write it down, iron out the inevitable kinks, fight with editors and peer reviewers to get your research publish... and to do all that faster than your competitors. Unless you can prove that you have great potential, then it is likely that committee will prefer someone who has published papers over someone who has almost published papers.
Comment: You may not be able to say it, but your advisor certainly can.
Answer: I am afraid that "I've been scooped" during the job interview in academia will be perceived as an upscale version of "a dog ate my coursework" excuse, particularly if a candidate has no publications at all.

Academic jobs usually require PhD, and PhD students are usually expected to publish a few papers during their PhD. At a very least one would expect papers based on PhD thesis.
Scooping is possible if the candidate presented their result publicly but was too slow to publish it. In academia "publish or perish" is an important motto, particularly for early  and mid-career academics. A proven inability to publish results in time is not something hiring committees will particularly like.
Comment: The OP didn't say they had *no* publications. Having a dissertation get scooped is fairly common in pure mathematics, especially if the problem is worth working on. In my view, this is really an advising failure, because it's the advisor's job to know who else might be working on a student's problem. But I have no idea how it's viewed by hiring committees.
Comment: @ElizabethHenning I think it's harsh to say it's a failure of advising.  The only way to guarantee that no one else is working on a project is to pick a project that 0 people have interest in, which is for obvious reasons not a great advantage in finding jobs.
Comment: Your first point is highly dependent on the University, as well as the discipline. In my discipline, at my alma mater, publications were *absolutely not required* for a PhD. Having at least one publication obviously helps tremendously for postdoc applications but that's a different matter. Anecdotally, I was an outlier in my peer group with two publications during my PhD. Both the mean and the median was less than 1.
Comment: -1 "A proven inability to publish results in time" is only appropriate phrasing if you're talking about an established pattern of behaviour extending over a significant period of time. All we know is that the asker was scooped once.
Comment: Also, since a person's probability of being scooped is at least partly a function of the "hotness" of the area in which they work, and also at least partly a function of the respective environments in which they and their competitors are working, it feels problematic to assign all of the blame to the person individually when this happens. It's not good for a job candidate to use scooping as an excuse for a poor track record, but by no means every case of scooping involves slow work / laziness.
Comment: @ElizabethHenning The OP also did not say they are the candidate.
Comment: @DavidRicherby Good luck explaining the difference to a selection committee, BTW. I wish they were so understanding.
Answer: Getting scooped will only really reflect badly on you if you could have avoided it, e.g. by working harder. If it happens, and you publish your paper anyway, just a bit later than someone else's, it might be a minor negative when applying for jobs (this one paper of yours had less impact than it might have done), but it's unlikely to be a huge blow, particularly if you've published other good papers. After all, at least you independently had the good idea in question.
By contrast, moaning about getting scooped, and using it as an excuse for why you don't have many papers, will reflect badly on you. It will come across as an unwillingness to take personal responsibility when things go wrong for you, which is not a desirable quality in a candidate.
TL;DR: One scooped paper won't kill your chances. A lack of publications overall might well, depending on the job. Having few publications and making weak excuses for why will almost certainly kill off your chances.
Answer: My experience is that "scooping" doesn't actually happen. The way one would define it is that you had an idea that you talked about at some conference or similar, and someone else published it before you. But how do you prove that you really were the first to think of this? Oftentimes, ideas are "out there": they follow from the review others have done, and everyone has the same idea.
As a committee, I would call bull shit. (Excuse my language.) If you had the idea first, and just took six months longer than someone else to get it submitted, it seems quite unlikely that an editor or reviewer would know about the competing paper. Both would likely have gotten published. So I agree with the other answer that says that a committee would like call this excuse the equivalent of "dog ate my homework". It just sounds like an excuse.
Comment: *.. it seems quite unlikely that an editor or reviewer would know about the competing paper.* What? Practically everyone posts on the arXiv before submitting to a journal.
Comment: I think to say scooping doesn't actually happen is too strong, since it has happened publicly before - c.f. the discovery of the dwarf planet Haumea, in which Michael Brown was (arguably) scooped by José Luis Ortiz Moreno.
Comment: I don't know about your field but, in mine, I'd be surprised if I managed to write a paper where none of me, my co-authors, the editor and the referees noticed that a paper with very similar results had already been published by somebody else.
Comment: @WolfgangBangerth I mean what I said: between all of us, it would be unusual for none of us to have noticed, given that ArXiv, conferences and people talking to each other all give routes to find out. Especially given that part of the due diligence of writing papers is to actively research the literature.
Comment: @DavidRicherby Exactly. This sort of "due diligence" is what I meant when I said it was (probably) an advising failure. In nearly every instance that I personally know of where a dissertation problem got scooped, the advisor hadn't been in regular contact with others in their field.
Comment: Not the idea. It was a problem that was posed. Someone else was thinking about it. Maybe scooped is the wrong word. It wasn't that my idea was stolen.
Comment: @ElizabethHenning: That's the point -- everyone posts everywhere. If you're 6 months late in submitting your article, what are the chances that reviewers or editors have seen the preprint? It hasn't found its way into wide circulation yet, isn't referenced yet, etc. And what are the chances that reviewers and editors will reject a paper that is likely slightly different based on the existence of a preprint somewhere for which there is no indication that it might actually be published?
Comment: @Allure: Yes, of course it happens. But I would claim with about the same frequency with which homeworks are eaten by dogs: it happens, but it's far more rarely than claimed by our students. Similarly, scooping happens far more rarely than claimed on the Academia StackExchange forum.
Comment: @Gradstudent "Scooped" is exactly the right word.
Comment: @DavidRicherby Really? You and the others you mention would know of *every* paper that's been quietly posted on a preprint server somewhere six months ago, that hasn't been published since (because it's still going through the motions), and that (like your own paper) is likely not revolutionary? I mean, if it's some breakthrough that's being talked about in the community, then sure. But how many such papers do we typically write?
Answer: Don't think of this along the lines of "getting scooped".
A department works very hard to identify and recruit faculty that will be competitive in the academic domain. Anything in your portfolio that might suggest there may be an issue with staying competitive will reflect negatively on a candidate.
These days, developing faculty work very hard to make their portfolio look "right".  They publish like crazy, apply for and get travel awards, compete like mad for "best abstract" recognitions, make sure they're nominated for and lobby aggressively for young investigator awards....
If your portfolio doesn't look like that, the next applicant's might.  Given a choice between the two extreme portfolios, a hot department will opt for the nice-looking one every time.  A not-so-hot department might take what they can get.
If there is something wrong with your portfolio, get introspective, and go to interviews prepared to discuss how you're going to improve it, instead of offering excuses about why it's not so hot.
Comment: @Gradstudent  my assumption is that is will vary by area.  There are fields where work is slow by nature, and pubs few and far between.  I suggest you go look up posted resumes for new young investigators in your field, and see what they look like.
Comment: What characterizes an application that looks right? I should keep this is mind the next time I apply...


How does the Windows 7 DVD know if it started the PC?

Question: How does the Windows 7 DVD know if it started the PC?
The DVD does not read the environment for that, since I already tried that route by editting its environment (batch files) to reflect that of the system boot disc. That failed.
So, the DVD must be writing to and reading from the system boot disk as it boots and as it is about to run an install procedure.
The question is which files and/or folders are involved, along with which registry settings has it written to, and subsequently reads from, if any?
The result I want is to be able to boot the Windows 7 DVD and do an in-place (version to version) upgrade (now referred to as repair installation).
Microsoft's insistence that such a repair installation take place only from the desktop, pretty much leaves out anyone that cannot get to the desktop to repair it. Duh.
Think outside Microsoft's box and the answer is there somewhere. Try a mantra other than Microsoft's... :-)
Answer: I think you might mean the
<code>HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MiniNT
</code>
registry key, which exists only if it's running in a PE environment.
Comment: I think that that registry key would not enable the DVD to boot and then run the in-place, version to version, upgrade at that point. I would still need to get to the Windows 7 desktop.


How can we make the tag 'ingredient-selection' less confusing?

Question: A lot of new users are confused about the tag 'ingredient-selection'. It would seem to apply to things like "Why were apples used in this recipe" or "Should I substitute peaches or pears in this recipe?", but it does not. Instead it to things like "How can I tell an apple is ripe?" Both types of questions have to do with selecting ingredients; is there something we can rename the tag to to make it more clear?
Answer: The tag wiki would seem to make it clear, and we went out of our way to create that new tag in order to quarantine the original (horrible and now-abolished) "ingredients" tag.
I am personally on record several times as saying that if users are consistently using the wrong tag, then it is probably a problem with the tag, not the users. So I'm usually on the lookout for this type of tag problem, and well-aware of the frustrating misuse of this particular tag. But I'm just not sure how much clearer we can make it without resorting to even worse tags like [shopping].
To select means to "carefully choose as being the best or most suitable". That doesn't connote (to me) questions about substitutions, or recipe modification, or about ingredients in general.
I think the existing tag is the best option among many lukewarm alternatives, but of course, I'm open to suggestions as well.
Answer: I thought of another possibility: ingredient-quality.
We already have food-identification which covers the non-"quality" side of selection.
Would this be less easily abused, or possibly worse?