What is considered a healthy weight loss and body fat decrease?

Question: Is there any information on what is considered a healthy (and sustainable) weight and body fat % loss? How many pounds/bf% for each week can I compare my results against so that I know I'm making good progress and that the loss I'm experiencing is sustainable and long term.
Comment: Do you remember your weight when you were in great shape? That might help you set goals. I arbitrarily decided on 1.5 pounds a month after I retired at 61. I was afraid my old skin would sag and I'd lose too much muscle mass at a higher rate and I had no reason to rush. I dropped from 187 to 151 at that rate and have held at 147-151 for the last 3 years. The skin sag only shows during planks so no 6 pack but my shoulders are awesome in the right light. I also got my cholesterol, blood pressure, etc into perfect ranges and cut my food expenses. "Pounds per week" sounds a little scary to me.
Comment: Sustainable for how long? And who are we talking about here--a 5'2'' 25-year old hiking woman, or a 60-year old 6' 200'' sedentary man, or a sumo wrestler who just quit the sport?
Comment: @Dave: 215 lb, 6', 50 year old man (me) - moderately active.  I guess I was looking more for % change based on current weight, etc. rather than specific for me.
Comment: Part of my point is that there may not be such a number for the general case.
Comment: [This guy](http://youtu.be/qX9FSZJu448?t=4m32s) says he lost 140 pounds in ten months, which is a little more than 3 pounds a week. He had huge amounts of fat to lose, though, because approximately 300 pounds at the beginning.
Answer: Your fat storage can only release 69 kcal/kg per day from your fat mass to be consume as energy. If you use up more energy then that it will be taken from somewhere else. Probably muscle mass.
I will make the assumption that the cell itself is not consumed in the process, therefor the only weight contribution is lipids and water. Water mass is far less and pretty constant in comparison to fat. The energy content of fat in adipose tissue is approximatly 9000[kcal/kg]*80% = 7200 kcal/kg.
What this means is that the fat you have on your body dictates how much caloric deficit you can be in before you start losing fat free mass as it is also shown here.
If you weight somewhere around 130kg, with 73kg lean mass and 57kg fat mass. You can use almost 69 * 57 ~= 4000 kcal/day from your fat storage as energy without making too much sacrifice on muscle mass. That can be up to 7 [days] * 4000[kcal/day] / 7000[kcal/kg] = 4kg of fatloss per week. Almost 9 lbs!

90kg, 17kg fat mass, you can use only 69*16 ~= 1200 kcal/day. 1,2 kg
(~3 lbs) per week.
85kg, 12kg fat mass = 0.8kg/week. (~1.7 lbs/week)
80kg, 7kg fat mass = 0.5kg/week. (~1.1 lbs/week)

As you approach 5-6% body fat, your estimated maximum loss of body fat approaches 1 lbs.
Conclusion
So what we see is that 2-3lbs/week is a good estimate for a normal person to achieve a goal for the duration of a normal diet plan. As you get leaner the rule of thumb is getting harder to keep without starting to lose lean mass. Also if you are obese there are no problems to lose more then the 2-3lbs/week.
These calculation are estimates and should be seen as optimal release, this do not take metabolic adaptation and and other effects like hormonal issues into acount. What it shows is how much you can be in caloric deficit before you start losing muscle mass.
Comment: Do you have a study for the kCal/kg_fat, too? That number is discussed quite controversial on this site.
Comment: The kcal/kg fat I calculated as adipose tissue consist of 80% fat (wikipedia). Free fatty acids is metabolised as 9kcal/g . 1kg [fat tissue] * 80% * 9 kcal/g [energy density of fat] = 7200 kcal per kg adipose tissue. This is of course just the pure hydrolysis to free fatty acids, I don't think that it would be much loss in that process. So the actual number would be at least in that ball park. I can look it up though.
Comment: Would be great if you could do so, as there has been a lot of discussion but I have never seen something reliable for any of those numbers.
Comment: I would guess that most derive it from this equation as a form of total potential energy of the fat storage. In that way this calculation is obviously correct. So my equations above should be viewed as potential weight loss, not ACTUAL weight loss.
Comment: http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=17848938&ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum . This pretty much is everything I was talking about, someone have later made a simplified model into what I showed above (which I haven't found yet).
Answer: This is different for everyone and every situation. What might be considered a healthy "weight loss rate" for someone in a certain situation can be totally different for someone else or in another situation.
Providing your body with the right nutrients and get the right amount of exercise will automatically result in your ideal "weight loss rate".
From experience I found that loosing 5 lbs per week is normal for most people if you adjust you lifestyle and eating habits.
Try this: Consume more water rich foods (vegetables and fruit) and limit your intake of sugar and fast carbohydrates.
I'd recommend you to do some research on healthy nutrition an exercise and see how your body is reacting to it. More than measuring your success by your weight loss, I would suggest you to measure your success by how you feel.
Comment: 5lbs/week as a prolonged diet? ... please. That is a near ~2000kcal deficit or even more depending on fat mass. Please include something to support that claim.
Comment: Welcome to Physical Fitness! Great with your own experience, you can improve your answer with more detail on that (e.g. total weightloss, time & other activities. Also, if possible, add some references.
Answer: The aim most of us have is to have a more healthy, fulfilled life. Weight is no impediment to have a healthy life free from diseases, opposite to the opinions held previously by so called experts. However, if it becomes a matter of concern to you, and you want to lose weight to fit in a dress, for example, or if you feel only losing weight will make you feel better, you need to keep a realistic plan of action in place.
Reduce 15 kgs in 2 months
Diet Changes
1. Eat Right

Stay Hydrated
Skip the booze
Keep your taste buds happy too.

Exercise Plans:

Find your Basal Metabolism Rate
Set realistic calorie consumption goals.
Find an exercise you like to do. And stick to it!
Join a Gym
Comment: "Weight is no impediment"? - What about the millions who are overweight and the stress that the extra weight puts on their joints and mobility?  I'm not sure they would agree with your statement.
Comment: "Weight is no impediment to have a healthy life free from diseases, opposite to the opinions held previously by so called experts" [Citation needed].


iPad mini - change ID for App Store

Question: I have 2 email addresses. The App store uses email address 2 and I can't remember the password for that. Anyway I'd rather it used email address 1. I have checked through Settings>iCloud, Settings>iTunes & App Store and both are logged into email address 1. Settings>Messages was logged into email address 2 but I've signed out of that. Even so I still can't get the App Store to let me login with email address 1.
Answer: The easiest thing to for you to do is to go to the Apple ID management page and reset your password for your Apple ID associated with email address 1.
Comment: Thanks for the suggestion but I've already tried that. The problem is that on the App store it's showing one identity and on other Apps it's showing a different one.

iPad mini - change ID for App Store


Avraham leaving the donkey behind

Question: The Medrash states that Avraham asked Yitzchak what he saw and he answer that he saw the divine presence. However,when he asked Eliezer and Yishmael they both answered that they saw nothing. The passuk says that Avraham left them behind with the donkey. My question is, it is understandable that he left both Eliezer and Yishmael behind, but why leave the donkey which would be helpful carrying the wood for the altar?
Comment: perhaps they need to climb or to be alone without any thing which may trouble concentration. Agav, in mikdash they go without donkey. The parking was before the entry
Answer: Here's an old chidush of mine which addresses your question.
Many times, if not always, Neviim make a vague statement or perform an act which requires the person or people they are addressing to concentrate on the message. Leaving someone to figure it out themselves seems to be a practical way of having someone accept a message. So we find prophets placing their cloaks upon a new prophet, putting sticks together, telling stories about a poor man's sheep etc the list goes on.
Here, Avraham was hinting to Yitzchok what was going to be happening. He did this by separating the three items, the wood, the knife, and the fire between Yitzchok and himself.
Yitzchok who stood to be consumed, received the wood, the item which also stood to be consumed. Avraham who was to act as the destructive force, took the knife and the fire. With this act he gave a type of hint to Yitzchok.
Rashi on this passuk points out that the words they walked on together mean Avraham was going just as happily as Yitzchok who didn't sense anything. By the next passuk, Yitzchok asks Avraham where is the sacrifice, to which Avraham responds ambiguously, Hashem will show his sacrifice. Rashi points out this was a way of telling Yitzchok if there will be no sheep, than you, Yitzchok will be the offering.
Rashi again notes the second time the Torah mentions them walking together as meaning now they both went with the same degree of intent even though Yitzchok now knew he stood to be slaughtered.
So although the implications are that Yitzchok's curiosity was aroused simply by the missing sheep, I am adding that the first step to that awareness was the dispensing of the sacrificial items.
This symbolic act of Avraham was dependant on his placing the wood on Yitzchok, not upon the donkey.
Hope you like:)
Comment: Nice :)........
Answer: There are meforshim who connect the חֲמוֹר with the word חֹמֶר (matter). This means that the entire location of the mizbeach was a holy place and only animals that were acceptable for korbanos could be brought there. This is similar to the halachos of the Bais hamikdash or the Mishkan.
I should note that Yishmael and Eliezer seem to have felt that there was no oddity in doing this so that it may have been the normal procedure. That is that non-sacrificial animals were never brought into the "sacred area".
Similarly, the mefarshim that speak of Eliezer and Yishmael being treated similarly to the donkey, place the emphasis on that. They do not explicitly say why the donkey was left behind. However, since the two were left behind with the donkey, it can be inferred that the donkey being left behind was the normal and expected behavior that did not need further explanaation.
As an example Aish.com discusses this concept (while explaining another matter)  and brings the medrash

We recall the discussion between Abraham and Isaac as they headed
  toward Mount Moriah for the impending sacrifice of Isaac. Abraham
  looked up and saw a mountain with a peculiar cloud tied to the
  mountain. Isaac shared this vision, but the others who accompanied
  them saw only the mountain.
The Midrash explains:
[Abraham] saw a cloud tied to the mountain, and said: "It appears that
  that is the place where the Holy One, blessed be He, told me to
  sacrifice my son." ... He then said to him: "Isaac, my son, seest thou
  what I see?" "Yes," he replied. Said he to his two servants: "See ye
  what I see? " No," they answered. [Midrash Rabbah , Genesis 56:1-2)
Since the servants saw only the mountain, the physical reality, and
  not the cloud which represents the metaphysical, Abraham tells them to
  stay behind with the donkey. (Interestingly, the Hebrew world for
  "donkey," chamor, is related to the word for "physical," chomer.) Only
  Abraham and Isaac see the cloud tied to the mountain, and only they
  will continue the spiritual journey.
Comment: The interpretation of a Biblical term in terms of the implications of a word in medieval Hebrew translating a Greek term is unconvincing. And unsourced.
Comment: @mevaqesh I adder a reference to the medrash and one of the places the reference is found.
Comment: This does not seem to be from the Midrash, but an interpolation of Aish.com. So to clarify, when you say "there are meforshim" you mean Aish.com.
Comment: The Midrash itself says _nothing_ about why the donkey was not brought. Addressing _only_ why the _n'arim_ were treated comparably to the donkey.
Comment: @mevaqesh No. that is only one place. I also saw references to the Rambam, Maharal, Chabad, and others. I just did not put them all in to the post itsefl in order to save bandwidth. Rav Hirsch also has the implication in his commentary but does not explicitly speak of it.

Avraham leaving the donkey behind


What should a/c low side/high side pressures be after weeks of non-use?

Question: I removed the compressor clutch relay last week when I began noticing severe engine bog when the compressor engages. I'm Hopeful that I can minimize further damage and salvage whatever I can. Now it's a week later and I finally had time to hook up my gages (compressor still disabled via clutch relay removal). Low side and high side both read ~60 psi. I know hi should be 198-228 and low 22-36 psi, but I assume that is when the system is running. So my question is, would a good system be expected to maintain those pressures after days/weeks?
Answer: If you are asking if the pressures should remain as low/high for several weeks, no. It's not going to do that. There's two principles with an A/C system at play here. In order for the A/C to work, there has to be a high pressure side where, after the charge is compressed is run through the condenser and is cooled (while still at pressure). Then the low side, where the cooled refrigerant has a chance to expand and thermodynamics has a chance to do it's thing and this cools the inside of your car. The second part is there has to be flow in order for this these things to happen. Refrigerant has to be able to flow through the system. If it doesn't, you'd never get the first part to happen. Due to this, given time, refrigerant is going to equalize between the low/high sides over time.
Something to think about ... when, after running your A/C system and you shut your engine down. If you've listened to your A/C system after the fact, you'll hear it hissing. This is the refrigerant equalizing through the system. Really, it won't take it too long for the equalization to occur. Probably going to be equalized within a 1/2 hour of shutdown.
Comment: If the system uses r134a, equalized pressures at 75° should be 75 psi. At 70°, 70 psi.
Comment: Thanks! I wonder if you could advise me on something further. What is the best way to diagnose if the compressor has simply failed versus self destructed with metal fragment release? I'd like to determine that myself before to make sure I buy exactly what I need before getting started. Will it be obvious to whoever I take it to for gas removal?
Comment: Please ask that as a new question! :o)
Comment: I did. Here it is.(https://mechanics.stackexchange.com/questions/50182/ac-compressor-diagnosis-failed-or-failed-with-shrapnel).


How to activate disabled Gmail account with mobile number

Question: My account is disabled due to suspicious accesses. I have forgot alternate mail id attached but my mobile number is attached with Gmail Account. Can I activate my account with the help of mobile number?
Answer: If Google disabled your account, you should be directed to page upon login with general information about why and a link to appeal/recover the account.
You can follow steps here: http://www.webesupport.com/how-to-recover-google-account-disabled-due-to-suspicious-activity

Why Google disables accounts
Google wants to ensure that everyone has a chance to safely and securely connect and communicate. To help preserve this environment, Google reserves the right to:

Suspend a Google Account from using a particular product or the entire Google Accounts system if there is a violation of the Google Terms of Service, product-specific Terms of Service (available on the product page), or product-specific policies.
Terminate your account at any time, for any reason, with or without notice.
  Next steps for disabled accounts

Please start by reviewing the relevant Terms of Service. Then, if you think your account should not have been disabled, please contact us. By contacting us to look into this issue, you certify that you're the owner of the account and consent to allowing us to review the contents of your account to evaluate your request.

If the disable was in error, you will hear back and the account can be restored.
If you've simply forgotten or lost access to the account, you can go through the Google Account Recovery flow.
So mobile number work when you recover account, or when Google team will contact you after finding the error and ask to send mobile number or send any code to your register mobile number.


How to save multiple buffers

Question: After modifying multiple files, how can I save all their buffers?
Comment: `C-h a` (`apropos-command`) is your friend. `C-h a save buffers` tells you about commands whose names match `save` and `buffers`.
Comment: `multi-occur` is not dependent on projectile. It is a vanill Emacs command from standard library `replace.el`.  Why mention (and link to) projectile here? Is there really something pertinent about projectile in your question? Search and replace seem to be irrelevant to the question, as well.
Comment: Thanks for clarifying that `multi-occur` is built in. I mentioned projectile specifically as it is a feature and package that people may not know about. Most folks are diligent at saving while editing, so the use case of updating multiple files at a time makes more sense within the context of a library like projectile and/or multi-occur. The same goes for using a macro to edit multiple buffers. My thought was that including these libs helps widen the discoverability of helpful features.
Answer: After making the changes you can save the open buffers using save-some-buffers. This is bound C-x s by default.
Here is what the docs say.
Save some modified file-visiting buffers.  Asks user about each one.
You can answer `y' to save, `n' not to save, `C-r' to look at the
buffer in question with `view-buffer' before deciding or `d' to
view the differences using `diff-buffer-with-file'.

You can use C-u C-x s to save without asking.
Answer: M-x ibuffer * u S is quite convenient for this as well, because you can add/remove selected buffers with m or u before saving with S.
Comment: Likwise, `buffer-menu`.

How to save multiple buffers


Acrobat PDF loses interactivity in native mobile viewers - what to do?

Question: I created an interactive PDF in Acrobat with footnote links and back buttons for figures referenced in the text.  It's on my site as a download and it works fine when downloaded to desktop but when downloaded to a mobile device the links and back buttons no longer work.  I've read that native mobile pdf viewers don't render interactive elements very well if at all but I was wondering if anyone knows of a workaround for this?
Comment: Can you provide an example PDF showing this issue? There are different ways to go about adding interactivity to a PDF, so knowing exactly what you did would require seeing the file. Also, are you trying to support as many web and native based PDF viewers as possible?
Comment: Thanks for responding. The file can be downloaded from my website at [https://relativityoflight.com ] using the Download PDF button on the landing page.  And ideally we would want it to work on as many native mobile PDF viewers as possible.
Answer:
downloaded to a mobile device the links and back buttons no longer work

Not all PDF readers support all PDF features, so the simpler you make a PDF the more it will work as expected.
I did not see anything wrong with any Links (please update your question to provide a specific link not working).
As for the "Back" buttons, I can see that they do not follow the PDF standard. On page 14 you have a Button Widget annotation, with a A action with the following info.
/N /GoBack
/S /Named
The S is correct, but the N is not, it should be PrevPage. See the Named actions table in the PDF specification.
I edited your PDF so that particular "Back" button on page 14 used PrevPage instead of GoBack and it worked as expected.
So for the "Back" buttons at least you should review how you created the PDF.
However, my real suggestion would be to just remove the "Back" buttons. PDF viewing software provides better/easier ways for users to navigate pages of a PDF, than clicking on a button on the page (which may not even be visible depending on zoom).
Comment: Thank you Ryan!  I will definitely look into your suggestions.  I wasn't aware that there were differences in how the back buttons were created.  I wasn't involved in that part of the process.  As for the links, I was referring to the footnote links, not links to the figures, which seem to work.  But none of the footnote links worked for me on the iphone.


Which bonds need to be broken to form a liquid?

Question: I'm confused whether it's the intermolecular forces, or the bonds that are being broken when a substance changes state? Does this differ among different types of compounds (eg. covalent, ionic, covalent network solid? What is actually happening when they change state?
Answer: It could be either chemical bonds or weaker intermolecular forces that change during a change of state. Water is held together by hydrogen bonds and make its boiling point higher than for analogous compounds.
Sulfur changes both ways with temperature:

Sulfur forms polyatomic molecules with different chemical formulas, the best-known allotrope being octasulfur, cyclo-S8... At 95.2 °C (203.4 °F), below its melting temperature, cyclo-octasulfur changes from α-octasulfur to the β-polymorph. The structure of the S8 ring is virtually unchanged by this phase change, which affects the intermolecular interactions. Between its melting and boiling temperatures, octasulfur changes its allotrope again, turning from β-octasulfur to γ-sulfur, again accompanied by a lower density but increased viscosity due to the formation of polymers. At higher temperatures, the viscosity decreases as depolymerization occurs. Source

Metallic bonds are delocalized, so in melting, there is no real change in bonding (though on boiling, a metallic vapor is quite different).
One could say, though, that this is simply a matter of definition: chemical bonds act over shorter distances, and intermolecular forces over longer, but they are not intrinsically different, the polar or hydrogen bond being an example of one that bridges these realms.
Answer: In reality if a substance is in liquid phase , then not all intermolecular bonds are broken between molecules but some of them and this results in the creation of groups of molecules.In gases all intermolecular bonds are broken between molecules.
The intramolecular bonds are not broken during a phase transition and that is why I posted my own answer instead of comment on DrMoisphe's answer.


How to write numbers concerning physical quantities?

Question: Is there a rule specifying how one should separate thousands in numbers? Should I put a comma in this phrase, "500–1500 ohms", so it would become "500–1,500 ohms"? If so why?
Comment: @ChrisH Except that the recommendations of in that guide would have you write 10 000 (space as separator) rather than 10,000, and although I understand why in terms of international differences in separators (points, rather than commas in continental Europe), as the document admits, this use is not universal (by any means, I would say).
Comment: You can do it either way. If this is for publication, check the stylesheet of the publication you're writing for.
Comment: Many (in my experience even most) publications (@robusto) don't go into anything like this much detail in their guidelines. But they shouldn't need to becausethe[SI guide](https://www.google.com/url?q=https://physics.nist.gov/cuu/pdf/sp811.pdf&sa=U&ved=2ahUKEwjLtfW-mK7gAhUSUhUIHVMZAbsQFjABegQICBAB&usg=AOvVaw1_V6SXsBSpmKbx1h67nOhb) (pdf) covers all this and more
Comment: @David it does of course depends on your publication. I used commas in my thesis, I admit, but would generally go with the unambiguous thin space in a paper. These are both scientific publications though, and normal media might well choose a comma
Answer: It depends on the style of the journal you are publishing in, and in the old days this would be handled for you by sub-editors. Like any other aspect of text presentation, clarity and ease of comprehension are the overriding considerations. The screen-shot below from the Journal of Biological Chemistry (from the old days) shows how it is often handled. To summarize and explain why:

In text one writes 1500 (no comma separator) but 15,000. This aids perception, it being regarded that 1500 can easily be interpreted by the brain, but with more digits the chance of confusion increases.
In tables one writes 1,500 if the table also contains numbers with more digits (10,000 etc.). Again this aids perception, but in this case of the table as a whole. Alignment of the thousands helps comparisons (just as one should align decimal numbers at the point, as you see in the table).

So, if you accept the arguments I have given justifying this style, I would suggest that you write "500–1500 ohms". (Actually, better 'ohm' as units are generally kept in the singular — e.g. 'ml' in the example.)
But should you ever use commas?
A comment from @Chris_H draws attention to the SI Guide. In general this agrees with my recommendation, above, except that it suggests that the thin space should be used instead of the comma:

10.5.3 Grouping digits
Because the comma is widely used as the decimal marker outside the United States, it should not be used to separate digits into groups of three. Instead, digits should be separated into groups of three, counting from the decimal marker towards the left and right, by the use of a thin, fixed space. However, this practice is not usually followed for numbers having only four digits on either side of the decimal marker except when uniformity in a table is desired.

As a footnote remarks, this practice is not universally followed — not at all in the scientific journals in my area, where, in any case, the standard of sub-editing and typesetting of tables has declined drastically*. Although possible in a table, I would regard it is ambiguous and impractical to use a thin space (do you know how to obtain one?) in body text, and would write '15,000' and '1500' myself. (I would not use, and have never seen, separators after the decimal point.)
Another situation where you might wish to avoid commas (or indeed any separator), is where the data are to be subsequently processed by computer. The only solution I can see to that is to replace 15,000 ohm by 15 × 103, so that in a table you would have ohm (× 10–3) in the header row specifying the units.
*A recent article in Journal of Biological Chemistry — perhaps the most respected journal in its field — has '2,018' and '1475' in the same column of the same table (Table 3 of J. Biol. Chem. (2019) 294(5) 1753–1762), with the numbers (of two to four digits) left-aligned.
Comment: Seeing as "ohm" is the full word for the unit, not a symbol or an abbreviation, why should "ohm" be used in the singular after a plural numeral? We wouldn't write "1500 metre", so why "1500 ohm"?
Comment: @RosieF I wondered if anyone would pick that up. However, unless you use the Greek symbol Ω (which type-setters hate) I would have thought that in a scientific paper it would be regarded as an abbreviation. (One never writes metre in a scientific paper.) But you may be right.
Answer: It is worth noting that there are also recommendations for writing ranges properly.
You should consult the NIST National Institute of Standards and Technology Guide for the Use of the International System of Units (SI). This is very useful and it specifically recommends to write so "It is clear to which unit symbol a numerical value belongs and which mathematical operation applies  to  the  value  of  a  quantity  because  forms  such  as  the  following  are  used."
So use
1MHz to 10 MHz or (1 to 10) MHz not: 1 MHz – 10 MHz or 1 to 10 MHz
20 ºC to 30 ºC or (20 to 30) ºC not: 20 ºC – 30 ºC or 20 to 30 ºC


Why is the "brain in a vat" scenario meaningful?

Question: In class we discussed the famous "brain in a vat" case, where since you can't differentiate between that case and "reality", you have no way of knowing that you are, in fact, in reality. But what I don't understand is, why is it a meaningful scenario? Isn't reality just what we perceive anyway? If I have no way of knowing that I'm just a brain in a vat, and I never will, then how does this make what I see as "reality" any less real?
Comment: Ewkochin, what @Einer shows is that there are philosophers who would disagree with your idea that everything beyond perception is uninteresting. The difference between the two is universality, which is essential in human interaction.
Comment: The 'brain in a vat' is a skeptical hypothesis. Philosophical skepticism uses skeptical hypotheses to question the possibility of certainty in knowledge. The usefulness of BIV (brain in a vat) lies more in what it shows (no certainty in knowledge) rather than what it implies (*you* being a brain in a vat).
Comment: Right. But my point is that it doesn't actually imply any lack of certainty in knowledge, since it simply means adding the caveat "in reality as I perceive it" to anything I think I know, thus - "in reality as I perceive it, it's not raining". Now, since reality as I perceive it is all that exists, what would it matter if I was just a brain in a vat?
Comment: The point of the argument is not whether you are a brain in a vat (and whether it matters) but whether you can *know* if you are a brain in a vat or not. This is the skeptical argument: *I do not know that not-P.... If I do not know that not-P, then I do not know S.... I do not know that S.* BIV serves as the skeptical hypothesis, a starting point (a thought experiment) where you cannot (and are not allowed to) *know* if not-P or P is the case.
Comment: @ewkochin It is a very modest account of existence that reality as you perceive it is all that exists. Some might challenge that. Your perception might be fooled by something that you are unaware of. With you account, colors would seize to exists when everyone turn colorblind. If someone proposes: "What if there were colors, and we are all colorblind?" you would ask here "How is that scenario meaningful if perception and reality are congruent? We will never know if there are colors anyway!"
Comment: @Einer And yet, we are told that there are animals that can see more colors than us. But naturally, we don't have names for these colors. Because to us, they don't exist. We do, in fact have a limited ability to see colors, and I fail to understand the difference between the situation being as it is, where there exists some sea creatures with more ability than me; and the world in which the colors we currently see were the only colors.
Comment: @Glen W Right, but I am saying that because there is no possibility or option of my knowing that I am or am not a brain in vat, I'm not. Because in the world as I perceive it, which is all their is, I am not a brain in a vat.
Answer:
In class we discussed the famous "brain in a vat" case, where since you can't differentiate between that case and "reality", you have no way of knowing that you are, in fact, in reality. But what I don't understand is, why is it a meaningful scenario? Isn't reality just what we perceive anyway?

I'm not a fan of the brain in the vat thought experiment because it is rather silly and understates the significance of many important problems. However, your argument against it is not much good.
There are two problems with the claim that reality is what we perceive. First, many scientific explanations invoke things that nobody has ever perceived and that perhaps nobody ever will perceive. For example, nobody has seen the core of the sun. Maybe nobody ever will. Nobody has ever seen a dinosaur, only dinosaur skeletons. But in both instances there are many explanations about those unperceived entities. There is no way of explaining how the world works without them, so as far as we know they are real.
Furthermore, your perceptions are not just showing the world the way it is. Rather, they introduce many layers of interpretation. This is what gives rise to optical illusions. Your visual system makes assumptions about the way the world works, so if you know those assumptions you can produce misleading effects by making suitable images or models.
Reality as we know it is not what we perceive, nor is it derived from sense perception. Under some circumstances we can interpret what we see as true and other circumstances we know better. So under some circumstances we disregard what we see in light of an explanation. Rather our knowledge about how the world works comes from making guesses and then criticising those guesses. Sense perception can help us criticise guesses, but we can't know what the world is like just by looking at it. For more discussion of this issue see "The Beginning of Infinity" by David Deutsch, chapter 2. See also Chapter I of "Realism and the Aim of Science" by Karl Popper.

If I have no way of knowing that I'm just a brain in a vat, and I never will, then how does this make what I see as "reality" any less real?

We do know that we are not brains in vats. The world is extremely complex. If we were just brains in vats there would have to be some hardware running some very complex simulation. The only difference between the brain in vat explanation and the true explanation is the the brain in vat explanation slaps a label on everything saying it is a simulation. This label explains nothing about how the world works and so it is an unexplained complication of our existing explanations and should be rejected. See "The Fabric of Reality" by David Deutsch, Chapter 4.
Answer: I feel that whether or not we know the truth, the truth still exists is one of the essential points of BIV. It is a starting point. You suggested that we all need to prepend "in reality as I perceive it" to the beginning of any statement as an nonessential caveat. BIV is suggesting that it is an essential caveat and that we need to continually maintain that perspective as annoyingly uncertain as it is, lest our ego's trick us into maintaining or arguing for less encompassing paradigms like Newtonian physics vs. Einsteinium physics or shadows on the wall as opposed to reality.


Salesforce Mobile SDK - refresh token validity period

Question: Is there any document or reference about the validity period of refreshtoken of Mobile SDK? I have a hybrid local app and if I let the app to be idle for a while and use back, it's failing with the log Undefind character, error is not defined in line 336 at Cordova.force.js This line is the error argument of the forcetkRefresh function.
I'm unable to catch when this is expiring or what to do next.
I'm using Mobile SDK version 2.1
Answer:
The refresh token may have an indefinite lifetime, persisting for an admin-configured interval or until explicitly revoked by the end-user.

Since refresh tokens may expire or be revoked by the user outside the control of the client application, the client must handle failure to obtain an access token, typically by replaying the protocol from the start.
In your connected app settings in salesforce you will find refresh token policy .Hope this helps
Comment: Thanks for the reply @Mohith, I have chosen **Refresh token is valid until revoked** option as the Refresh Token Policy as in above which am thinking it should valid until I explicitly revoke that. But still without a clue for me it's failing
Comment: @highfive I have observed this and it happens when salesforce servers due to some reason stop for small fraction of seconds.In UI during this time we get salesforce Internal Server error .You can visit trust.salesforce.com to figure the health of your server Instance .Also change your org to some other instance and replicate issue if it persists .Best wishes
Answer: As in Mohith's answer the refresh token may have an indefinite lifetime. The issue here is not regarding the validity period but in the SDK it's calling an incorrect failure function at line 336 of cordova.force.js. error should be replaced by fail. This has been fixed in v2.2


What do you call the first areas that you find yourself in after getting off an airplane at an airport?

Question: What do you call the first areas that you find yourself in after getting off an airplane at an airport? After doing some research, I found the term "passenger terminal", but it's too vague and seem to refer to a big chunk of the airport, what are the parts of the passenger terminal you get off to after getting off an airplane?
Comment: The gate area? The concourse? The arrivals lounge? Different airports are configured differently from one another. You arrive at a terminal one way or another, however. That is more or less the definition of what a terminal is.
Comment: From an international flight where you have to go through customs, or a domestic flight where you just exist to the same area people board?
Answer: Although I'm not an expert in airport terminology, a terminal is the word you are looking for. Terminals are actually not that large (these are just the areas where passengers go to board their flights). The only specific parts of a terminal I can think of are the seating area, the tarmac (where the plane is), and the air jetty (the tunnel that leads from the seating area out over the tarmac). If you find any additional information I would love to hear it!


Referencing a WixVariable defined in a WiX Library Project from a WiX Setup Project

Question: I'm trying to configure a WiX setup and library so that the version of one of the files in the library is used as the Product/@Version in the setup.
Background
In a setup with the files defined locally this is relatively straightforward in that assuming the component project is referenced by the WiX project and then configured:
  <Component Id="Company.Assembly" Guid="[GUID]">
    <File Id="Company.AssemblyFile"
          Name="Company.Assembly.dll" KeyPath="yes"
          DiskId="1"
          Source="$(var.Company.Assembly.TargetPath)" />
  </Component>

Then the product version can be set as
  <Product Id="[GUID]"
           Name="Product Name"
           Language="1033"
           Version="!(bind.FileVersion.$(var.Company.AssemblyFile
                    .TargetFileName))"
           Manufacturer="Company Name"
           UpgradeCode="[GUID]">

Issue
So having moved all the components to a WiX Library project it's no longer possible to directly reference the !(bind.FileVersion.$(var.Company.AssemblyFile.TargetFileName)) variable.
I've tried configuring a WixVariable in the library
WixVariable Id="BuildVersion" Value="!(bind.FileVersion.Company.AssemblyFile)"/>

And then reference that from the setup
  <Product Id="[GUID]"
           Name="Product Name"
           Language="1033"
           Version="!(wix.BuildVersion)"
           Manufacturer="Company Name"
           UpgradeCode="[GUID]">

Without success.
Is there some additional step or syntax required in either the library or setup to make the WixVariable (or some derivation of it) accessible from the setup?
Answer: I hear this one a lot and I don't think the WiX documentation does a particularly good job of explaining the situation, so here it is. The short answer is that your syntax is correct; a variable declared with the WixVariable element is referenced with the syntax !(wix.VariableName) and you can use variables that have been defined in a referenced library so !(wix.BuildVersion) is correct for the example you've given above. The reason it doesn't work is because the value needs to be verified during the compilation phase but it's not being generated until the linking phase. So here's the long answer:
There are two distinct types of variable that you can reference in a *.wxs file; preprocessor variables and binder (or linker) variables. The former is referenced with the $ syntax, e.g. $(var.VariableName) and the latter is referenced with the ! syntax, e.g. !(bind.FileVersion.FileId). The key difference is simple: preprocessor variables are parsed during the compile phase (by candle.exe) and binder variables are parsed during the link phase (by light.exe). The compiler is responsible for taking the source *.wxs files and compiling them to *.wixobj files; it doesn't process the actual payload so it's not in a position to read version information from a linked file. The *.wixobj files are then passed to the linker which processes the payload and creates the MSI database. The linker is responsible for collecting metadata from the payload which is why it can provide values for variables like !(bind.FileVersion.FileId).
Note that a variable declared with the WixVariable element is referenced with the ! syntax so it's a binder variable; it will be available to light.exe but it won't be available to candle.exe. This is a problem because candle.exe applies validation to certain fields such as Product/@Version. It has no idea what !(wix.BuildVersion) will evaluate to so it can't verify that it will yield a valid version. In contrast, you can get away with !(bind.FileVersion.FileId) because candle is satisfied at compile time that it will resolve to a valid version at link time (FileId is a direct reference to a file in the product so candle trusts that it will exist to yield a version number on link).
So you can use !(wix.BuildVersion) anywhere else in your *.wxs but you can't use it as a value for Product/@Version. As far as I know the only binder variable you can use here is !(bind.FileVersion.FileId) but obviously this is no good if you want to get the value from a referenced library. Otherwise you'll just have to get your version information from somewhere else and pass it into WiX so it's available at compile time. If you're using MSBuild it can query version information with the GetAssemblyIdentity task and can pass this to WiX via the DefineConstants property. The following targets in your *.wixproj file should do it:
<Target Name="BeforeBuild">
  <GetAssemblyIdentity AssemblyFiles="[Path.To.Target.File]">
    <Output TaskParameter="Assemblies" ItemName="AsmInfo" />
  </GetAssemblyIdentity>
  <CreateProperty Value="%(AsmInfo.Version)">
    <Output TaskParameter="Value" PropertyName="BuildVersion" />
  </CreateProperty>
  <CreateProperty Value="$(DefineConstants)">
    <Output TaskParameter="Value" PropertyName="DefineConstantsOriginal" />
  </CreateProperty>
  <CreateProperty Value="$(DefineConstants);BuildVersion=$(BuildVersion)">
    <Output TaskParameter="Value" PropertyName="DefineConstants" />
  </CreateProperty>
</Target>
<Target Name="AfterBuild">
  <CreateProperty Value="$(DefineConstantsOriginal)">
    <Output TaskParameter="Value" PropertyName="DefineConstants" />
  </CreateProperty>
</Target>

The BuildVersion property will be passed to candle.exe so you can reference it with the preprocessor variable $(var.BuildVersion). This certainly isn't as clean as keeping it all in the *.wxs file but it's one way of getting the version information into candle so it can be used as a variable in Product/@Version. I'd certainly like to hear any better ways of doing this.
Comment: Thanks, very thorough answer. Funnily enough you've also answered my follow up question about how to write a variable to DefineConstants.
Answer: I had a similar issue when using Heat.exe, this allowed me to override the source variable without messing with system environment variables or other such:
"%wix%bin\heat.exe" dir "$(SolutionDir)Web\obj\$(Configuration)\Package" -cg PACKAGEFILES -gg -g1 -sreg -srd -dr DEPLOYFOLDER -var wix.PackageSource="$(SolutionDir)Web\obj\$(Configuration)\Package" -out "$(SolutionDir)WebInstaller\PackageFragment.wxs"
I think this syntax can be used for any variable declaration that will not otherwise work at linking time:
<wix.YOURVAR="VALUE">-in command line/<!(wix.YOURVAR="VALUE")>-in .WXS files

Maybe helpful in other places too.


Set Registry Keys from Domain Policy

Question: Is it possible to push out changes to the registry on a local computer from the domain policy?  Or does a special script need to be written to do so?
Answer: It's perfectly acceptable to use Group Policy to push out registry changes via Preferences as squillman mentioned.  Read up on Preferences before you start though, they don't behave in the same way as genuine Policies (sticky etc).  Also, there's a bit of getting around the correct syntax to use in the policy template - get it wrong and you'll be scratching your head for ages trying to figure it out.
Jon
Answer: You can set registry keys via GPO prefence settings in a W2K8 domain. In a W2K3 domain you can only set security on registry keys via GPO, AFAIK.
Comment: -1 You can use the GPO preferences in a w2k3 domain.  You just need to install the client side extensions for older clients and have a Vista/Windows 7/W2k8 box with the gpmc installed to actually create/update the policies.

If you don't want to do the above you can always just create a policy that includes a startup/login script that updates the registry.

Set Registry Keys from Domain Policy


Capital gains tax on US treasury bonds

Question: If one buys 30 year bonds directly from the treasury, I understand the semi-annual interests are taxable at federal level. But what about capital gains in case the bonds are purchased at a discount from the face value. How exactly are they taxed?
Comment: @chepner _bills_ are only up to one year, and are discount-only as you say. Marketable **notes** from 1 to 10 years **and bonds** over 10 years (currently only 30) **do pay semiannual coupon** (unless 'stripped'), and in addition may auction at discount _or_ premium. See the navigation list at the left of the page you link. (But not _savings bonds_ which are entirely different in spite of the similar word.)
Comment: I'm not sure I understand - when buying bonds initially from Treasury at a discount, that is not a capital gain, that is simply your purchase price. The term 'discount' is perhaps a misnomer; the paid price is the fair value of the bond, but it is simply different from the face value ultimately redeemable due to the effective interest being earned over the lifetime of the bond.
Comment: I meant the gain one will realize upon maturity (Difference between face value and purchase price).
Comment: The difference between the purchase price and the face value *is* the interest: https://www.treasurydirect.gov/indiv/research/indepth/tbills/res_tbill.htm
Comment: You may be thinking of savings bonds, the accrued interest on which compounds semi-annually.
Answer: When any non-exempt bond (not just Treasuries) is bought at more than a 'de minimis' discount, the 'guaranteed' gain is treated for tax purposes as additional interest, amortized over the term of the bond (if more than one year). See the section Discount on Debt Instruments in chapter 1 of publication 550, downloadable in PDF or on the web (IDK why 2017 isn't up yet, but this provision hasn't changed recently).
Although the actual computations are fairly complicated (see also pub 1212), if you hold the bond through a financial institution like a broker -- or TreasuryDirect, which is actually a fiscal agent, IIRC the Pittsburgh FRB -- they will do the computation and provide it to you and the IRS on Form 1099-OID during filing season, and you include it on Schedule B just like 'real' interest on 1099-INT. Marketable Treasuries in particular are book-entry only (since about 2000 IIRC) so you almost have to hold through some institution.
The 'de minimis' threshold is based on the bond's term, and for a 30-year bond is 7.5%; it looks to me like only a few recent 30-year auctions exceeded that (and both were reopenings, which you could simply avoid). Under the threshold you just report it as a capital gain at redemption or sale whichever comes first, in the usual fashion. I don't recall if TreasuryDirect issues you a 1099-B but if not this case is simple enough to do by hand (no transaction costs, no account costs, no margin, no basis adjustment, ...).
Comment: That was a clear explanation. Thanks a lot. To sum up, please check if I have understood correct. If discount from face value is over 7.5%, then 1) Treasury issues 1099 OID in addition to 1099 INT. Hence, along with the taxes on interrest rate, one has to pay additional taxes as per 1099 OID. 2) Upon redemption or sale, 1099 B may be issued. In such case, the purpose will be for IRS to verify the tax payments (both on interest and par value discount) over previous years.

Capital gains tax on US treasury bonds


Nero Mist granite countertop

Question: I'm in the process of choosing a material for a new kitchen counter.  One that I'm considering is a honed Nero Mist granite.  I'm trying to find out from someone who has the same type of granite how often they have to seal it.  I've read that some granite needs yearly sealing.  Concerning black granite, I've read that they don't need sealing as often.  However, that seems to be canceled out by another source which stated that honed granite often needs to be sealed more frequently that highly polished granite.  If you have this material, can you please let me know how it's holding up and how often you have to seal it?  Thanks!
Answer: I sealed some nearly black granite over 20 years ago and it never needed resealing. The first time food oil touched it , it made a mark in the granite. So I went to the dealer and he sold me a 500 ml bottle of a clear oil-like liquid. It worked great; it needed less than one ounce/sq.yd. ... Found it in my garage- PSI, premium silicon impregnator ( Lithofin brand), made in Germany.
Comment: Was your granite polished or honed?  Polished has a mirror-like finish, honed has a flatter finish because the surface is more irregular.  The question is really asking whether honed granite needs sealing more often.
Comment: Polished. It has often been exposed to oily foods with no problem.

Nero Mist granite countertop


How to use encryption in SQLite database

Question: I have developed an application for which I am using sqlite database .Now I want to encrypt the database using SQLcipher .Can I encrypt my existing database using SQLcipher?
Answer: SQLCipher for Android Application Integration
This tutorial will cover integrating the binaries of SQLCipher for Android into an Android application. This tutorial assumes the Android SDK is already installed on the local development machine.
Create sample Android application
To create a sample Android application, issue the following commands:
% mkdir demo-app
% cd demo-app
% android create project \
  --target android-10 \
  --name demoapp \
  --path . \
  --activity HelloSQLCipherActivity \
  --package com.demo.sqlcipher

Obtaining binaries
The source code for SQLCipher for Android is publicly maintained on Github.com, the current binary release can be found here. For information on building the source of SQLCipher for Android, please see the instructions below. We will manually download and extract the contents of the compressed tar file into your application root directory with the commands below:
% curl -L -o sqlcipher-for-android.zip https://s3.amazonaws.com/sqlcipher/SQLCipher+for+Android+v3.1.0.zip
% unzip sqlcipher-for-android.zip

We need to copy the various library and asset files over into the root directory of our application. Execute the following commands:
% cp -R SQLCipher\ for\ Android\ v3.1.0/libs/* libs
% cp -R SQLCipher\ for\ Android\ v3.1.0/libs/*assets

The files for your demo application should look similar to this structure:

Integration
Launch Eclipse and choose File -> New -> Android Project from the menu. Give the project a name and choose Create project from existing source pointing to your application root directory. It should look similar to this:

Next we need to reference the 3 jar files in our libs directory. Right click on the project node in the Package Explorer and select Build Path -> "Configure Build Path...". Select the Libraries tab and press the "Add JARs..." button. Select commons-codec.jar, guava-r09.jar and sqlcipher.jar. After selecting these three jars, the screen should appear like this:

Next we will modify the source of the default activity to properly initialize the native libraries for SQLCipher and then create our database file inserting a record. In particular, note the import of net.sqlcipher.database.SQLiteDatabase instead of android.database.sqlite.SQLiteDatabase as well as the call to SQLiteDatabase.loadLibs(this). The call to SQLiteDatabase.loadLibs(this) must occur before any other database operation.
package com.demo.sqlcipher;

import java.io.File;
import net.sqlcipher.database.SQLiteDatabase;
import android.app.Activity;
import android.os.Bundle;

public class HelloSQLCipherActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        InitializeSQLCipher();
    }

    private void InitializeSQLCipher() {
        SQLiteDatabase.loadLibs(this);
        File databaseFile = getDatabasePath("demo.db");
        databaseFile.mkdirs();
        databaseFile.delete();
        SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(databaseFile, "test123", null);
        database.execSQL("create table t1(a, b)");
        database.execSQL("insert into t1(a, b) values(?, ?)", new Object[]{"one for the money",
                                                                        "two for the show"});
    }
}

The sample application should now be able to run on either an emulator or device.
SQLCipher for Android Build Tutorial
This tutorial will cover building the source code for SQLCipher for Android from scratch. This tutorial targets revision 7 of the Android NDK and is intended for complication under Linux or OSX environments.
System environment requrements
In order to build the source of SQLCipher for Android several tools are required. Several development kits including the Android SDK, Android NDK and the JDK need to be present on the build machine. We will need the ANDROID_NDK_ROOT environment variable available on the PATH. You will also need Git to acquire the source tree. To verify your PATH is properly configured, execute the following command:
% which ndk-build
/Users/nparker/bin/android-ndk/ndk-build

If you receive ndk-build not found you will need to add the following to your .bashrc or corresponding shell configuration file. Note the ~/bin/android-ndk path below represents the location on my machine for the root directory of the Android NDK, adjust accordingly:
export ANDROID_NDK_ROOT=~/bin/android-ndk
export PATH=$ANDROID_NDK_ROOT:$PATH

We will use Make as our base build tool for interacting with the NDK toolchain.
Get the source
The source code for SQLCipher for Android is maintained publicly on Github.com. We will start by cloning the repository locally:
% cd ~/code
% git clone git://github.com/sqlcipher/android-database-sqlcipher.git

Building
The process of building the code is split into two different phases. The first time this is performed we need to initialize various git submodules that SQLCipher for Android depends on. This is all automated through Make.
% cd android-database-sqlcipher
% make init

Once git has finished pulling down the various submodules required for compilation, we can begin the build process:
% make
This process will take some time to complete. Once it has completed, you should have the following files available for integration into your application's libs directory:
% tree libs
libs
├── armeabi
│   ├── libdatabase_sqlcipher.so
│   ├── libsqlcipher_android.so
│   └── libstlport_shared.so
├── commons-codec.jar
├── guava-r09.jar
└── sqlcipher.jar

Localization dependencies
SQLCipher for Android depends on localization data from the ICU project. SQLCipher for Android will attempt to use a system provided ICU localization data file called icudt46l.dat located in the /system/usr/icu directory if available. If that is not found, SQLCipher for Android will attempt to unzip the icudt46l.zip file located within the applications asset directory. It is recommended that the icudt46.zip file be included with your application for best platform compatibility.
Reference:https://www.zetetic.net/sqlcipher/sqlcipher-for-android/
Comment: Can you clarify exactly how you found the binary?  I don't see a link where you say it can be found "here" and when I go to the binary download from the Zetetic page I wind up at https://bintray.com/bintray/jcenter/net.zetetic%3Aandroid-database-sqlcipher/3.3.1-2/view which says "No direct downloads selected for this package." and I can't figure out how to select one.
Comment: btw, your link works great for 3.1.0, but if I naively replace it with 3.3.1 or 3.3.1-2 it fails.


Adjusting disk brake pad positions

Question: I have had experience on a couple of mountain bikes when I could not adjust the disk brake caliper positions far enough left or right to keep the pads from rubbing the rotor a little. Is this common and/or normal? Is there a something I'm missing, or should I just bend it a little?
Comment: Tyre? Disc Pad? Help! Can you clarify whether you mean 'disk brakes', 'linear pull brakes', 'cantilever brakes', etc.?
Comment: The make and model info would be good too, of the bike and the disc brake.
Comment: One is a Specialized Rockhopper with Avid brakes. I don't remember the other, but it is another brand. I don't know the difference between linear pull or cantilever brakes, but there is a cable the runs down to the calipers -- it's not hydraulic.
Comment: I think the confusion is from you saying "rubbing the tire a little".  No brakes should rub the tire, of course, but disk brakes are a good foot away from the tire, whereas rim brakes are directly adjacent to it.  Both disk brakes and rim brakes have "calipers" -- that being a generic term for something that closes in on both sides.
Comment: You're right, Daniel. I really meant the pads rub on the disk -- you cannot adjust the caliper position far enough to avoid this.
Answer: You are not alone. These brakes require constant adjustment and are not fit for purpose. The recommendation is to upgrade to Avid BB7's or a hydraulic system. Read the litany of complaints:
http://www.mtbr.com/cat/brakes/disc-brake-system/avid/bb5-mechanical-disc-brake/prd_414627_1507crx.aspx
Before you tear them off the bike in disgust you may want to take a read of the Park Tool instructions for adjusting Avid mechanical disk brakes:
http://www.parktool.com/blog/repair-help/avid-reg-mechanical-disc-adjustment
This explains quite clearly how the brakes actually work - the outer pad moves whereas the inner pad does not. The disk gets pushed across by the outer pad to hit the inner pad. Note that the more expensive BB7's allow more adjustment and that the even more expensive hydraulic systems work differently, pushing both pads out to meet the disc rather than just 'bending it across'.
Good rim brakes are better than cheap disc brakes and your bike unfortunately has the latter. I recommend that you upgrade the brakes to the best mechanical system you can afford rather than spend any more time trying to adjust what sounds to me to be a flawed product.
Answer: Ultimately after 3 months of average riding you will get some rub from disc brakes, because of the heating and cooling the disc gets slightly warped and shaped. If it is slowing down your wheel, as opposed to just heating it, then I suggest you get it serviced (bled and adjusted). I have pad control on my Avid Juicy 7's and only use it little, once dialed in it's where I like it for control purposes.

Adjusting disk brake pad positions


gabor wavelet and gabor transform

Question: I was reading a paper 'A Flexible Framework for Local Phase Coherence Computation' (paper URL) on using wavelets for local phase coherence. I just want to be sure. Is the gabor wavelet the same as the gabor function in the gabor transform (STFT)? If not, can we use a Windowed Fourier Transform instead?
Answer: The Gabor wavelet is (almost) the same as the Morlet wavelet (some authors distinguish these two by an additional constant to fulfill the wavelet's admissibility condition). And yes, it is the same function as in the Gabor transform (gaussian windowed oscillation).
The application of phase coherence should be independent of the underlying wavelet and the nature of the transform (Wavelet, Gabor/STFT, other weird metrics). Essentially important is the concept of reproducing kernels and the intrinsic (Heisenberg) uncertainty that influence you measure of phase coherence and must be taken care of.
Comment: Hi, is it possible for you to write down the formula for Gabor wavelet/Gabor transform(STFT)?
Comment: @André Uhhh... almost ? Unless otherwise specified the Morlet is real valued whereas the Gabor - complex.
Comment: @Sektor: What is your view on the question above?
Comment: Generally, speaking - yeah, they are the same. But not if we speak strictly - there are noticeable differences between the two and also the Gabor function is different from what you want it to be, i.e. the part that we integrate in the STFT, that is actually a complex exponential multiplied by a Gaussian function :)
Comment: Again if we loosen up - they are the same :)
Comment: @Sektor: Can you write down the formula for both Gabor transform (STFT) and Gabor wavelet transform?

gabor wavelet and gabor transform


Can't get deoplete plugin working in Neovim

Question: I have installed deoplete plugin into my Neovim using dein. I have put let g:deoplete#enable_at_startup = 1 into my init.vim and I can see the autocomplete list when I type in the insert mode - so far so good. However I am not able to autocomplete the word I am typing from the list which has appeared (I guess it should be done using Tab but none of the keys I tried worked). I am a Vim beginner so I am actually getting lost now.
Answer: Vim uses Ctrl-n (next item) and Ctrl-p (previous item), Ctrl-y (accept match) or Ctrl-e (cancel) and so on for completion. See :h ins-completion-menu and :h popupmenu-keys for details.
The following deoplete settings may help (they use Tab, Enter and Esc) - see the comments for what they do:
"use <tab> for completion
function! TabWrap()
    if pumvisible()
        return "\<C-N>"
    elseif strpart( getline('.'), 0, col('.') - 1 ) =~ '^\s*$'
        return "\<tab>"
    elseif &omnifunc !~ ''
        return "\<C-X>\<C-O>"
    else
        return "\<C-N>"
    endif
endfunction

" power tab
imap <silent><expr><tab> TabWrap()

" Enter: complete&close popup if visible (so next Enter works); else: break undo
inoremap <silent><expr> <Cr> pumvisible() ?
            \ deoplete#mappings#close_popup() : "<C-g>u<Cr>"

" Ctrl-Space: summon FULL (synced) autocompletion
inoremap <silent><expr> <C-Space> deoplete#mappings#manual_complete()

" Escape: exit autocompletion, go to Normal mode
inoremap <silent><expr> <Esc> pumvisible() ? "<C-e><Esc>" : "<Esc>"

Answer: I've found that the Supertab plugin (https://github.com/ervandew/supertab) let me use tab for deoplete completions, without needing any additional configuration.


iPhone Remote app and Apple TV

Question: I have my Remote app set up on my iPhone to work with my Apple TV.  This was easy because my Apple TV is linked with my Apple ID Account (which is obviously identified with both my phone and my computer).  When I went to set my wife's Remote app up on her iPhone, I get a message that says "Turn on Home Sharing in iTunes on your computer or on Apple TV using the account [Name of Wife's Account]."
On the Apple TV, Home Sharing is on and I still get this message.
My wife does not have an Apple computer.  Only an iPad.  She does not use iTunes at all.
How does this work if she does not use iTunes?
Apple TV has Home sharing turned on and when I go into the Remote app on her phone and go into settings, it says Home Sharing is turned on.
I just want to link her phone up.  How do I do this and why do I have to?  Shouldn't there just be a way to use her phone as a remote without making it a part of my Home Sharing network?
Answer: Is home sharing activated for the same account? (If she uses a different apple ID, then the two devices won't bind).
In that case, pair the remote via the apple tv's settings (under general i believe)

iPhone Remote app and Apple TV


unable to update Magento to latest version from 2.2.4 to 2.3

Question: I am trying to update Magento 2.2.4 to Magento 2.3 via composer but I am getting below error:

Your requirements could not be resolved to an installable set of packages.

 Problem 1:
    - magento/inventory-composer-installer 1.0.3 requires composer-plugin-api ^1.1 -> no matching package found.
    - magento/product-community-edition 2.3.0 requires magento/inventory-composer-metapackage ^1.0.3 -> satisfiable by magento/inventory-composer-metapackage[1.0.3].
    - magento/inventory-composer-metapackage 1.0.3 requires magento/inventory-composer-installer ^1.0.3 -> satisfiable by magento/inventory-composer-installer[1.0.3].
    - Installation request for magento/product-community-edition 2.3.0 -> satisfiable by magento/product-community-edition[2.3.0].

Potential causes:
 - A typo in the package name
 - The package is not available in a stable-enough version according to your minimum-stability setting
   see <https://getcomposer.org/doc/04-schema.md#minimum-stability> for more details.

Read <https://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.

I did run below commands:
1: composer require magento/product-community-edition=2.3.0 --no-update
2: composer require –dev phpunit/phpunit:~6.2.0 friendsofphp/php-cs-fixer:~2.10.1 lusitanian/oauth:~0.8.10 pdepend/pdepend:2.5.2 sebastian/phpcpd:~3.0.0 squizlabs/php_codesniffer:3.2.2 –no-update
3: composer update

Comment: have check from here https://devdocs.magento.com/guides/v2.3/comp-mgr/cli/cli-upgrade.html#upgrade-cli-upgr
Comment: after composer update remove cache and generated folders
Comment: then do setup:upgrade
Comment: then run setup:static-content:deploy
Comment: composer update command gives above error
Answer: wget https://raw.githubusercontent.com/magento/magento2/2.3.0/dev/tools/UpgradeScripts/pre_composer_update_2.3.php
php -f pre_composer_update_2.3.php -- --root='<path/to/magento/install/dir>' --repo=https://repo.magento.com/
composer update
rm -rf <path/to/magento/install/dir>/var/cache/*
rm -rf <path/to/magento/install/dir>/var/page_cache/*
rm -rf <path/to/magento/install/dir>/generated/code/*
php bin/magento setup:upgrade

https://devdocs.magento.com/guides/v2.3/comp-mgr/cli/cli-upgrade.html#upgrade-cli-script


How to redeem a delta voucher on already booked upcoming trip

Question: I have a e-voucher from Delta airlines. One of my friend has booked a trip from detla which includes me too. How can I now redeem my e-voucher on the already booked trip?
Comment: If the flight was booked less than 24 hours ago, and is at least 7 days away, your friend can cancel it right now for a full refund. You can then book it again using your voucher. Otherwise, I'm not sure it's possible to apply a voucher to an already booked flight.
Answer: You can always try calling Delta and see what they say, but unfortunately Airlines are usually pretty picky on these types of things. I am certain that there is no way to do it online with an already existing reservation. Who knows? Maybe you will get a really nice agent on the phone who can pull some strings!


What are these minifigures?

Question: Does someone know what theme or set these minifigures are from?
Comment: Hi Brick Adventures, welcome to Bricks.SE.  It looks like Alex has answered this.  If you agree it is our custom in StackExchange-land to click the checkbox by the answer to indicate that you have accepted it.
Answer: First one is Ultron Sentry from Iron Man vs. Ultron (76029) set.

Second is a minifigure made with torso and legs from Duros Alliance Fighter, Jet Pack, Minifigure, Headgear Helmet SW Hoth Rebel Trooper, Minifigure, Visor Snow Goggles and unknown head. All come in Rebel Alliance Battle Pack (75133) most likely since it contains all parts and similar head piece seen in your picture.

Last one is Aaron - Flat Silver Visor, Clip, Curved Slope and Tow Ball on Back, without the slope and tow ball on the back it seems. It is from Moltor's Lava Smasher (70313)
Answer: The third one is Aaron from Nexo Knights. The first is an Avengers character. The second is likely Star Wars.

What are these minifigures?


Shipping calendar, cannot edit other peoples entries. Outlook/Exchange help

Question: A user can create/delete/edit my own entries into the Shipping Calendar; however, the user cannot update/edit another person's entry, i.e. make changes to an event that Tom/Sandy created. What should I (domain admin) do to grant permissions that would allow her to edit other peoples calendar entries on this shipping calendar? Outlook 2003/Exchange 2003 help.
Answer: The Permissions tab (right click -Properties-Permissions)on the public folder will let you select users or groups and apply specific permissions in a very granular fashion.  You can select from a list of predefined roles or apply permissions specifically.
This assumes you have the higher permission to set permissions on the folder.


Content Query Web Part modification issue

Question: I am trying to display columns from 2 different lists in a site in CQWP. Most of the blogs and MSDN articles asks to modify the xslt file, ContentQueryMain.xsl and ItemStyle.xsl, for displaying additional columns. When I opened my site in SPD, I cannot find the Styles Library folder. Is there any specific settings? Also all the articles displays example to show additional column from single list. I have 2 lists with same columns, Title and Description (Multiline rich textbox) and I want to display basically Description in CQWP. Please help.
Answer: The ContentQueryMain.xsl and ItemStyle.xsl are located in the Style Library in the RootSite of the sitecollection. Do not update the default styles defined is those files (others may depend on it). Rather add a new style to the file, or copy the files and update the references in the CQWP to the new XSL-files. To do this: export the webpart and update the corresponding properties: HeaderXslLink, ItemXslLink and MainXslLink.
In order to query multiple lists you must override the <property name="ListsOverride" type="string" /> value in the webpart definition file. To do this, export the webpart. Open the file with your favorite xml/texteditor (notepad? visualstudio?). And update the property to: <property name="ListsOverride" type="string"><![CDATA[<Lists><List ID="31A7C09D-52CC-4585-B998-A3F180A9BD07"/><List ID="7382D66D-2E4C-47CB-A95C-5EECD68F5E61"/></Lists> ]]></property>. Use the ID's of the lists you want to query. When done import the webpart again. (source)
Comment: Rich Text is stored as HTML in the Database, use `` to display it. Otherwise all special char will be html-escaped (`& -> &`)
Comment: Thanks a lot. Just one more query. Is it possible to display the top 1 item from each list rather than all list items?
Comment: Hmm, that depends on the data in your lists. And you probably have to write your own CAML-query (use the `QueryOverride` property).
Comment: I am still not able to display rich text content. I modified all settings. I can see my formatted text in textual format with some style sheets. Any help?


Can I move the opening of my screen door from the middle to the left?

Question: Hi We have a 12 ft sliding glass door off of our living room to our patio. It opens in the center third. Is there any way that the opening can be shifted to the left side and have the two fixed sections to the right? I would replace the whole thing but it would be very expensive to get the same quality as we have, which the past owners had installed. And honestly cannot afford it. Thank you for any help you can give.
Comment: Pictures would help.
Answer: Your post says "screen door" but it sounds like you want to change the sliding glass door and the screen along with it. Most glass door units are modular, the glass sections (stationary and sliding) are separate pieces and the track runs the whole width of the unit. If this is the case it may be possible to switch things around.
Take a good look at the unit, the sliding door should lift up and inwards for removal. Once removed you may be able to see whether or not the stationary units can be removed. Look for screws on the inside and outside that are holding the units in place. The stationary units can usually be lifted up and removed as well. If we represent the original arrangement as A-B-C (with "B" being the sliding door) you might be able to replace them in this configuration:
 B-C-A.
The panels are heavy, don't try it alone. Prepare a flat area to lay down the sliding door so you can refurbish/lubricate the wheels while you have it off (I use sawhorses). Some old glass units are NOT tempered safety glass and could hurt you terribly if broken, be careful. The weatherstripping scheme, as well as the latch, may require some ingenuity as the setup will not be the same.
Not all glass door assemblies are made to take apart like described, especially custom stuff.
Comment: To remove the sliding section you have to raise the wheels (lower the door) to provide some play so you can lift it over/off the track. There are usually adjustment screws accessed through holes at the bottom corners.


What would it feel like for an astronaut if his/her spacesuit ran out of air?

Question: I'm curious what it would feel like if an astronaut's spacesuit ran out of air while they were on mars, vs taking the suit off?

 inspired this question
Comment: Are you asking about exposure to vacuum or carbon dioxide buildup?
Comment: Due to carbon dioxide buildup, I believe they'd just pass out.
Comment: EVA space suits are pressured with pure oxygen to be more flexible. They can't run out of air thus.
Comment: It takes a while for the air in the suit to have its oxygen depleted. It's not immediate, more like at least 30 seconds -2 minutes before effects are noticed, depending on breathing rate.
Answer: Eva suits use pure oxygen. This allows much lower pressure and hence a more flexible suit than using air would. Atmospheric pressure on mars is about 1% of earths, even with pure oxygen that is too low to survive.
So the big question is what does the suit do when it runs out of oxygen. I see two posibilities.

The pressure in the suit remains the same, but replacement of CO2 with oxygen stops. The person will feel they are suffocating.
The pressure in the suit drops as CO2 is removed but not replaced. I suspect in this case with a conventional suit the person will quietly pass out and die, with a "mechanical counterpressure" suit the person will find themselves unable to breathe because the mechanical counterpressure is no longer balanced.
Comment: "The pressure in the suit remains the same, but replacement of CO2 with oxygen stops" That happens when the CO2 scrubber is saturated but not when oxygen tank is empty. So this possibility is wrong.


Trying to understand Newton's Second Law

Question: If I apply a force on an object at rest and it's velocity is constant (after force is applied) wouldn't that mean that the acceleration is 0? Then how would $F=Ma$ make sense? My thinking here is that change in position means change in velocity but that doesn't necessarily mean that there is a change in acceleration.
Comment: Welcome to SE. Please edit your title. "FMA" isn't a known acronym, so this title won't help the search tool on the site.
Comment: If it is at rest and then starts moving, the average acceleration is clearly not zero. Although, at any point in time, the instantaneous acceleration might be zero.
Comment: Your own words: "***after** force is applied*" explain it. The acceleration is only zero *after* force is being applied. Not *while* it is being applied.
Answer: It is normal that an object has a constant velocity while we apply a constant force. But it is an indication that there is another force acting in the opposite direction, usually some friction force.
In the expression $F = ma$, the $F$ is not an applied force, but the net force on the object. If the net force is zero, the acceleration is zero and the velocity is constant.
Comment: thank you. I didn't think about that either
Answer: $a$ is the rate of change of velocity. So if $a$ is zero, $v$ is constant and doesn't change over time.
So while you're applying a force, the velocity is changing and $F=ma$. After the force stops, the acceleration is 0, so the velocity stays the same
Answer:
My thinking here is that change in position means change in velocity

This is wrong. A change in position does not necessarily mean a change in velocity. If an object is moving at a constant velocity its position is changing. A change in position only means a non-zero velocity, not necessarily a changing velocity.

but that doesn't necessarily mean that there is a change in acceleration.

Similarly, a change in velocity implies a non-zero acceleration, not necessarily a change in acceleration.

You might also be getting confused about average acceleration vs instantaneous acceleration.
Clearly, in your example, there is an non-zero average acceleration since the velocity changed. This implies that at some point in time there was a non-zero instantaneous acceleration, but not necessarily at all times. In fact, the instantaneous acceleration is only non-zero during the time that the net force is being applied. Before the net force is applied (when the mass is at rest) or after the net force is applied (when the mass is moving at a constant velocity) the instantaneous acceleration is zero.
It may help for you to plot the position as a function of time. Then plot the slope of the position as a function of time (this is the velocity). Then plot the slope of the velocity as a  function of time (this is the acceleration).
Comment: yes thank you. I just checked back to look at this question and I think for some reason I didn't realize that if an object is stationary then starts moving it has definitely accelerated.
Answer:
If I apply a force on an object at rest and it's velocity is constant

This is not possible. Newton's first law already says that if you apply force, velocity will change. So the situation you describe cannot occur.
If you did apply force and velocity did not change, then the net force must also somehow be zero. Perhaps for example you are pushing the object into a wall, and we can say the wall must be exerting an equal and opposite force which cancels you out. Note that what matters is net force.
Comment: @GiorgioP No reference to action–reaction pairs is made in the answer, only the fact that the person→block and wall→block forces happen to be equal and opposite (not necessarily as an immediate application of Newton's third law).
Comment: You're right. Sorry, I misunderstood what was written. I am going to cancel my comment.
Answer: There's two things to note here. The first one is that both quantities $\mathbf{F}$ and $\mathbf{a}$ are actually functions of time, not just numbers. If one wants to be explicit, one can write this on a value-by-value basis as
$$\mathbf{F}(t) = m \cdot \mathbf{a}(t)$$
but the notation
$$\mathbf{F} = m\mathbf{a}$$
also makes sense provided you suitably "overload" the multiplication operator to take a function as one input, which is then defined pointwise. As a result of this, though, one way your situation can occur is if the force was only nonzero at a certain point in time. If it is later zero, the object need not keep accelerating. There is only acceleration so long as force is present at the same instant of time.
The second possibility concerns the more precise meaning of $\mathbf{F}$. It is not just "any" force, but rather it is the total of all forces acting on the object:
$$\mathbf{F} = \sum_{i \in I} \mathbf{F}_i$$
and thus another way your situation can occur (though not at all mutually exclusive with the first) is for one force to cancel another out. This is what happens when pushing a wheelbarrow at constant speed. The rolling friction is exactly counteracting the force from your hands.
Answer: Newton's laws of motion are the foundation of classical mechanics. Newton's second law states that, ''The rate of change in momentum of a body is directly proportional to the force imposed on it. The direction of change in momentum and the force imposed are indifferent'' and its mathematical expression is $F = ma$ where $F$ is the applied force, $m$ is the mass of a body and $a$ is acceleration or rate of change in velocity. If $a = 0$, there is no change in velocity over time which means no force is applied.

My thinking here is that change in position means change in velocity but that doesn't necessarily mean that there is a change in acceleration.

It is wrong. Acceleration is defined as change in velocity over time. And also there is no change in acceleration i.e acceleration is constant while force is applied but there is change in momentum. See the derivation of $F = ma$ here for better understanding.
So while a force is applied on a body there must be a change in velocity as time changes or acceleration. Note that the net force applied on a body shouldn't be zero or there will be no change in velocity. After the force stops working, the force on a body becomes zero and so velocity remains constant [According to the first law , there is no change in inertia of a body if there is no force working on it].
Answer:
If I apply a force on an object at rest and it's velocity is constant (after force is applied) wouldn't that mean that the acceleration is 0?

After the force is applied, i.e. when the force is no longer being applied, sure, that's right: No force means no acceleration, which in turn means constant speed/velocity, whether that is zero speed (i.e. stationary) or non-zero (i.e. moving).

Then how would $F=ma$ make sense?

This law tells you that the acceleration $a$ of a body at any particular point in time is proportional to the net force $F$ being exerted on it at that same point in time. Whilst you are pushing, you are exerting a force, and thus the object is accelerating. When you stop pushing, you are no longer exerting a force, and thus the object is no longer accelerating, though it very well may be moving (i.e. have non-zero speed/velocity).

An example involving a car:
When the car is stationary, its velocity is zero. When your foot is not on the gas/accelerator pedal, the force that the engine exerts on the car is zero, and thus the car's acceleration is also zero, meaning its velocity is not changing; the velocity stays at zero, i.e. the car remains stationary.
As soon as you press down on the pedal, the engine starts exerting a force on the car, meaning the car starts to speed up. If you hold your foot down on the pedal a certain amount, the force will be constant, meaning the acceleration will be constant, meaning that the rate at which the car's speed increases is also constant (assuming there is no friction between the car's tyres and the road). That is, suppose the car's mass is 1000kg, and the force exerted by the engine is 3000N. This means that the car's acceleration is 3000N/1000kg = 3 meters per second, per second. What this means is that after 1 second, the car's speed is 3m/s; and after another second has passed, it is 6/ms; and after another second, it is 9m/s; and so on — as long as your foot remains on the pedal that same amount, the car will continue to speed up at that same constant rate. That is what is meant by constant acceleration.
Release your foot from the pedal and the car will stop accelerating, so e.g. if you released the pedal after 3 seconds, the car's speed would be 9m/s, and it would remain at 9m/s until some other force acted on the car. In other words, the car would coast at 9m/s, despite no force acting on it. An example of such a subsequent force might be when you press the brake pedal, which would apply a force opposing the direction of motion, resulting in an acceleration opposing the direction of motion (a.k.a. a deceleration), resulting in the car slowing down to an eventual stop.
The only reason the car doesn't continue to coast indefinitely without application of the brakes is that there is indeed friction between the car and the road. Such friction acts in the same way as a braking force, but it is a much smaller force, so it takes much longer for the car to come to a complete stop.


Can I use icing sugar instead of caster sugar? Are they the same thing?

Question: So there is a cupcake recipe I wanna make and it's my first time making it also one of my first time making any dessert like this. I got some icing sugar but the recipe asked for caster sugar. Are they both the same? If not can I use icing sugar to replace it? I see they're both powdered sugar.
Comment: If I remember correctly, caster sugar is a superfine granulated sugar rather than a powdered sugar.
Answer: Icing sugar is much finer than caster sugar.  However this way round you can probably get away with it ("probably" because without the exact recipe it's hard to tell).  I have recipes for butter biscuits that differ only in one using caster sugar and the other using icing sugar, for example, and cake recipes that use icing sugar. Icing sugar clumps badly so can be less convenient, plus it used to be more expensive though these days there's nothing in it.
You must work by weight when substituting between coarse and fine sugar, as they pack very differently into volume measures.  If your recipe works by volume, you shoudl go out and get the right sugar.
What you can't do is use caster instead of icing sugar in icing, as there's not enough liquid for it to dissolve.
Comment: Here is the recipe:

**Chocolate cupcakes:**
 100g/3.5oz plain flour,
 100g/3.5 caster sugar,
 2 tbsp cocoa powder,
 3 tbsp veg oil,
 125ml water,
 1 tsp vanilla extract,
 0.5 tsp bicarb soda,
 0.5 tsp Apple cider vinegar,

**Chocolate Icing:**
300g vegan icing sugar,
100g dairy free margarine,
3 tbsp cocoa powder,
1 tsp vanilla extract
Comment: That's quite an unusual recipe, using bicarb + vinegar as the raising agent, no egg (I note the 'vegan' and 'dairy free'), and water. But it should be fine.


Where can I view Contact opportunity role object?

Question: Can any one tell me where can I view the list of  Opportunity Contact Role object  in a separate tab just as  we see  separate tabs for contacts, Leads, Opportunities ?
Answer: opportunityContactRole is a junction object between Opportunity and Contact.  It can only be customized through the picklist for Role
You view the OCR through either a related list on the Opportunity page layout and/or the Contact page layout.  If not appearing, then customize the page layout to add it.
Answer: It's not a tab object, it's seen by salesforce as more of a subservient, opportunity-specific object, so no separate tab was deemed necessary.  What purpose are you trying to fill?  Could a report solve your issue?
Comment: I would like to see the list of opportunity contact roles.
Comment: could a report solve your issue?  opps with contact roles?
Answer: Contact Roles on the Opportunity can be edited by going to Customize / Opportunities / Contact Roles on Opportunities.
You can't display contact roles on a tab unless you're using a custom object.
Here's a blog post that gives more information on contact roles and examples of the type of picklist values used by other companies.
http://garysmithpartnership.com/contact-roles/
Answer: You can view it by:
https://BaseDomain.lightning.force.com/lightning/o/OpportunityContactRole/list?filterName=Recent


Does the Python Software Foundation License permit relicensing to the GPL?

Question: Does the Python Software Foundation License permit relicensing to the GNU GPLv3 (or v2)?
Comment: It would be nice to have a table of licenses that permit re-licencing and with what requirements.
Comment: @vonbrand I wouldn't call it a "discussion" - since it's technically more an article. Concerning the subject though, we have a [tag](https://opensource.stackexchange.com/questions/tagged/license-compatibility) dedicated to it.
Comment: There is a [discussion on this in Wikipedia](https://en.wikipedia.org/wiki/License_compatibility)
Answer: You cannot re-license the individual PSFL-licensed work, because you are not the copyright holder and the copyright holder has not permitted you to do so. Python will remain under the PSFL; the only way to change this is for the copyright holder to issue it under a different license.
Instead, however, if you are merely interested in combining a PSFL-licensed work with GPL-licensed code, then you are interested in the question of whether the PSFL is GPL compatible.
The Free Software Foundation says of Python licensing for various versions:

License of Python 2.0.1, 2.1.1, and newer versions
This is a free software license and is compatible with the GNU GPL. Please note, however, that intermediate versions of Python (1.6b1, through 2.0 and 2.1) are under a different license (see below).
License of Python 1.6a2 and earlier versions (#Python1.6a2)
This is a free software license and is compatible with the GNU GPL. Please note, however, that newer versions of Python are under other licenses (see above and below).
License of Python 1.6b1 through 2.0 and 2.1
This is a free software license but is incompatible with the GNU GPL. The primary incompatibility is that this Python license is governed by the laws of the State of Virginia, in the USA, and the GPL does not permit this.

As long as you're not using a version of Python between 1.6b1 and 2.0 or version 2.1, your copy of Python is compatible with the GPL.
GPL compatibility does not allow you to simply relicense the Python interpreter in isolation, but it does mean that you can combine the interpreter with other works that are licensed under the GPL and license the entire combined work under the GPL, as required by the GPL.
In other words, you can comply with both licenses' requirements simultaneously. In the particular case of the GPL, this is possible because the set of restrictions imposed by the Python license is a subset of those imposed by the GPL.
Comment: @ThorSummoner You are free to include PSFL-licensed work in a combined work that is, as a whole, licensed under the GPL. You cannot re-license the individual PSFL-licensed work, because you are not the copyright holder and the copyright holder has not permitted you to do so. In your particular case, go ahead and make your GPL-licensed fork. Your original contributions will the GPL licensed, the PSFL-licensed work, considered in isolation, will remain PSFL-licensed. The work as a whole is GPL-licensed. See also https://www.gnu.org/licenses/gpl-faq.html#WhatDoesCompatMean
Comment: @ThorSummoner If you performed a [clean room rewrite](https://en.wikipedia.org/wiki/Clean_room_design) of the software without consulting the original code, then it is possible that your code *might* not be considered a derivative work under copyright law. In that case, if true, the work is all your own, and you may license it however you like. Otherwise, your work is a derivative work of the PSFL-licensed code (*even if no original line of code tangibly persists in your rewrite!*) and you must abide by the PSFL's terms for derivative works (e.g., preserve copyright notices, license text, etc)
Comment: I thought that re-licensing was distinct from license compatibility; In my case I want to fork a project licensed under the PSFL and release my fork under the GPL; I am already aware that I can use them together.
Comment: If the fork was a substantial re-write of the original project, could it be relicensed? That's a topic that I haven't came across any resources on yet.
Comment: Like many have said, you cannot "relicense" it without originl copyright holders' permission. But what you can do is fork it and then add GPL on top of PSFL. Since they are compatible, dual licensing is possible. You will have to maintain the original license terms of course.
Answer: If you get some code under the Python license, and you add some code you license under GPL, the result has to be licensed under the more restrictive license, i.e., GPL.
In any case, doing so is damaging. Your combination will become a pariah in the larger Python community, as it can't be included without tainting all. This is a sure recipe to have it die on the wine. The community will probably see you as disruptive, and shun you. Everybody loses.


How can I restore this scratched 1930s print?

Question: I could use some tips on restoring a scanned print of a family photograph from the 1930s. The photo is heavily scratched, but I would like to restore as much as possible. Any tips on removing the texture of scratches on the image? The foreground is very soft and I would like to improve definition and detail.
Answer: I took Nathan's image as a baseline then used Wavelet Decomposition with a rough select around the people to duplicate two layers of detail and re-merge it back in to try to sharpen without producing the sharpen artifacts you get from unsharp mask.

Per a request for methodology details:
I used GIMP 2.10

Layers Scale 2 through 5 and residual follow. (Scale 1 has almost no information).

I duplicated layers scale 3 & 4.

I also selected just the people and deleted everything else in the duplicated layers to apply the sharpen effect to just the people. Not Shown.
Besides a sharpen effect from duplicating layers, the reverse can be accomplished by deleting layers or painting gray over various level details in the wavelet decomposition to selectively remove different levels of detail, effectively blurring. You can even blur gross detail while keeping fine detail.
Editing just the residual can help remove color stains without impacting details.
Comment: This would be much more helpful if you explained how you did what you did. What software, for instance.
Comment: @Eric S - Explanation added per your request.
Comment: Outstanding! +1
Answer: Here is my image after removing major scratches and defects. I tried playing around with whole-image FFT to remove finer scratches and texture but could not find a good way to keep foreground details (e.g. hair, skin edges, etc.). This was VERY meticulous use of heal brush, and I don't have the patience to heal brush every scratch in this image.
Comment: FFT is helpful only for regularly occurring patterns, such as grids or halftone screens. Since scratches are *not* regular, FFT wouldn't be helpful.


Sharepoint Designer 2010 - Reusable Workflow - Content Type Document - Name of Document Library

Question: I am new in Sharepoint Platform, i have developed a reusable workflow on Document content type. The workflow is very easy, only send a email to "Document Owner". This workflow is prepared to apply on retention policy when a document has not been updated in three months.
In the body, i want specify the name of "Document Library" where the document is allocated, but i don´t find a variable who say me this value.
Please, could you help me?
Best regards
Answer: You can use this to get list / library name


Why is my question still on hold?

Question: Why is my question still on hold after a day?  I made it more specific.
Comment: When I reviewed it, I felt it was a duplicate of the question I linked in my comment. So I voted to leave closed.
Comment: It is closed as "unclear what you are asking" but it appears clear perhaps with revisions OP made . It may be a duplicate as Muru points out but in the mean time VTR now and then we can VTC as duplicate later? Could a mod step in and change the close reason?
Answer: Just follow this advice:

Please clarify your specific problem or add additional details to
  highlight exactly what you need. As it's currently written, it's hard
  to tell exactly what you're asking. See the How to Ask page for help
  clarifying this question. If this question can be reworded to fit the
  rules in the help center, please edit the question.

This message tells you what you can and need to do in order to get your question reopened:

You should take the Tour to make yourself familiar with the site.
You should read How do I ask a good question? to make sure you make your question a valuable one.

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In your case it would be helpful to search for the main error message – AppStream cache update failed – on AU as well as the internet in general. Try to get to the bottom of the problem and include the whole result of your research in your question. Please do not use comments to add information, instead edit the question directly.
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Why is my question still on hold?