parents dont agree for marriage on the basis of caste

Question: aoa.
i am a practicing muslimah, and I want to marry a practicing muslim boy from a good religious family. i talked to family about him around 2 years ago and they refused to even meet them because they are not from our caste. we are syed and they are malik. he and his family respect us a lot and have tried to meet my parents but my parents refuse. i know i cannot marry him without the permission of my guardian, but when the case is like this that they are refusing on the basis of caste which has no importance in islam, what can I do? in this case can I get someone else to be my wali?
Answer: Islam does not recognize any castes, but, when it came to Persia and India, the existing divisions in these regions were adopted among the local Muslim societies.  It developed as a result of ethnic segregation between the foreign conquerors and the local renverts, as well as influence of the indigenous Hindu culture.
Infact in the last sermon of Prophet (SAW) on  Ninth day of Dhul al Hijjah 10 A.H. in the valley of Mount Arafat, he said:

"...All mankind is from Adam and Eve, an Arab has no superiority over
  a non-Arab nor a non-Arab has any superiority over an Arab; also a
  white has no superiority over a black nor a black has any superiority
  over white except by piety and good action..."

You are right that caste has no importance in Islam. If you haven't already, you should try to explain the same to your parents in a respectful but truthful manner.
Also inquire with them if they know something about the boy or family that makes them reject the proposal. Perhaps they are using the 'caste' thing to be respectful to you and hide something which may upset you even more.
Alternately, if everything else if fine, try to get the help of your grand parents or uncles/aunts who are religious and understand your situation well.
At the end of the day, it is unlikely that someone on an online forum can help you much. You need help from someone closer to you.
For your wali question, please see this question:
Who can be wali, and in what order?


how can i make uneven distribution of lattice without changing the shape of object in the beginning

Question: I want my lattice to the shape as i showed in the beginning. the edge inside lattice is not not evenly distributed, becuz i want my plane to bend along those lines. How can i manipulate the lattice to that shape without changing the shape of my plane immediately?
Comment: I understand if we i use edit mode to lattice it will cause my plane to distort. I am just wondering how can i change the bending position to like this with out deforming my plane in the beginning. plus, i googled but did not find satisfied answers.
Comment: maybe use Mesh Deform modifier or even Surface Deform as your mesh is flat. You'll be able to make the cage mesh exactly fit your object mesh.
Answer: I don't know if you could have something very accurate with a lattice. Maybe you should try shapekeys or, if you have a reason to prefer a modifier, the Mesh Deform modifier or even the Surface Deform, as your object is a simple plane:

Create the object A, the one you want to deform.
Create the object B, a subdivided plane, it's the object that you'll use as the Surface Deform target.
Align its edge loops with the object A vertices.
Give your object A a Surface Deform modifier, choose object B as the target, click on the Bind button.
Select the object B, go in the Properties panel > Data > Shape Keys and create the shapekeys.
Now your object A will deform rather well.
Comment: thx for ur answer! I do not have a preference. I just want to bend my surface. I am new to blender and lattice is just the tool i googled and found. So if i just want to bend a surface, which tool will you suggest me to use?
Comment: the simplest one is to create shape keys on your mesh without any modifier, search for a tutorial on youtube: In few words you need to create one basis shapekey which will be the undeformed shape, them create as many shapekeys as you want, one for each deformation you want to create, then play with the vertices in Edit mode, and once back in object mode play with the value...


How to read signal from load cell?

Question: I took apart a weighing scale to get the load cell from it. The weight scale was capable of measuring up to 85 pounds with 5 grams precision. The voltage drop of the weight scale, however, is too small. It is about 0.4 to 1.5 millivolts. I need to read this somehow. I tried amplifying it with op-amps and did not work. I read about high resolution ADC like HX 711. What would the simplest way for reading and feeding the signal from the load cell to microcontroller without compromising the accuracy or precision?
Comment: The usual way is to use an 'instrumentation amplifier' which you can build up out of 2 or 3 opamps or use a read-made one. TI, Linear tech, Analog Deviecs, etc all make many, many options. That'll give you a reasonable signal which you can feed to the ADC of your choice.
Comment: Something like the INA125 is a common choice for load cells in hobbyist applications.
Comment: From the weight and resolution that you specified the A/D converter in the original unit appears to have been good to 8192 counts.
Comment: Have you considered to try to hack some of the amplifier and signal conditioning circuitry from the original unit?
Answer: The ADC that most of hobbyist use for Load cell is ADS1130. This is an 18 bit ADC with internal gain of 64 which transmits the converted bits serially. It would be easy to answer if you had mentioned the model of your microcontroller, because some of the microcontroller has amplifier embedded in it with high resolution bits of adc like Atmega16.

How to read signal from load cell?


Can a stripped USB charging cable electrify you and how dangerous would it be?

Question: I have a USB type C charging cable that I charge my cellphone with. Couple of days ago I found out that it got frayed on some parts of its plastic cover. I always charge my cellphone in bed and before sleeping. I'm kinda worry right now that I might have rolled onto the frayed part while sleeping and got electrified without noticing it due to the fact that the cellphone chargers output voltage is too low to be felt ( I read this somewhere ) but being electrified for hours ( when sleeping ) even by a low voltage must be really dangerous I suppose. Something I feel heartburn and shortness of breath but I've always had these problems and don't know if they are related to the charger story or not.
Comment: Welcome to SE.Electrical Engineering! 5V is not dangerous, even not for longer time. I'm voting to close this question as off-topic because it has nothing to do with Electrical *Engineering*.
Comment: You're fine. Get it replaced soon
Comment: Yes, you may be electrified if you happen to touch the bare wires. You will be exposed to roughly 5,000,000 microvolts.
Comment: The battery in the cellphone may be dangerous to have in bed with you particularly if it gets under you or the battery is overcharged.
Answer:
Can 5V kill you?

Short answer: YES  ...BUT....you'd have to broach the skin to subcutaneous layers or have lots of blood exposed in positions either side of the heart. So with a frayed USB cable (both ground and +5V exposed) an impossibly low risk for such local contact.
If your skin is intact the likely resistance is in the 10-100 kOhms range, so death would be impossible (insufficient current flow).
Reading this or this might help you. It's all about the current flowing.
This diagram is helpful:

What are the chances of a frayed USB cable killing me on contact?

Short answer: Impossibly low risk
I didn't say there is no risk because the situation is complex.
If all that is wrong is the DC cable is frayed and you are not bleeding or have open wounds for it to touch ….the risk is infinitesimally small. Current would flow only locally in the area of contact and you'd be unlikely to even feel it.
However the cellphone charger is connected to the AC mains 120/240V AC and the isolation/grounding on some chargers is questionable. Under these conditions you could get higher exposure ....but you'd need some other contact (typically a ground) on the other side of the body to get current to flow across the heart.
For example, picking up this frayed USB cord (and making contact subcutaneously) with the charger plugged in while standing in a bath of water with the taps on (where the water may well have a path to earth) could be very problematic with a poor charger design (but this is no longer a +5V problem).
Get a new charger or replace the cable. It is not worth the risk no matter how low the risk is.
...and put your cellphone on the nightstand for goodness sake....
You might also read this Q/A.
Comment: Thank you for taking your time and answering in a detailed way. I didn't necessarily mean being killed by having contact with a frayed cable as, well I'm still alive:) I was just worried about any long term effect... There is just something that I don't understand. On my charger it's written ( output: 5.0V=2700mA/9.0V=1800mA/12.0V=1350mA ) isn't it just too much? According to Google and your diagram 0.2 mA can be deadly... And I do want to buy another cable but the thing is in my country at least 95% of cables are fake, yet they are sold as original.
Comment: @Draku The current rating of the charger is irrelevant. The voltage however is important. In the case your cellphone it is unlikely that the charger negotiates 9 or 12V since the cellphone is a single LiPo cell. If however you were attached to a tablet or laptop that negotiated a higher voltage ….then this higher voltage would impact how much current flowed through a person. Higher voltage ...higher current. Fake cables being a problem is a separate issue.
Comment: Ok I think I understand by now. Even if I got electrified, the flow would be 5 (Voltage) ÷ 100000 ( the skin resistance ) = 0.00005A or 0.05 mA witch is almost nothing I guess.
Answer: Being exposed to 5V for extended times is absolutely harmless. Nothing to worry about.
However, you should still replace the cable. A frayed cable can create partial for full shorts and these can damage the charger or the phone and result in things overheating or breaking. The cable connector itself could get hot too.


Happy birthday, Philosophy.SE!

Question: Well, friends, it's been a whole year since we kicked off Philosophy.SE! I wanted to take a moment to reflect on our achievements and consider the road ahead. I'd love to hear about your favorite questions or answers from the past year, or any ideas you might have on interesting projects we might start putting together in our second year. Congratulations, everyone!
Answer: My favorite question is my own:

Is Kurt Gödel's Incompleteness Theorem a "cheap trick"?

My second favorite is still an open one, I see:

Are the unexamined lives of others worth examining?

Whenever my reading swings around to philosophy, it's nice to know that Philosophy.SE is waiting in the wings to take my questions.  It's been a while since I've been an active member of the community, but I really appreciate the work y'all are doing to keep this site active.
Answer: I just wanted to mention that there are now 180 questions and answers on Philosophy.SE that earned a great question or answer badge (i.e., that have a minimum of 10 votes.)
Please check them out here! I think it is pretty inspiring that the community has generated this much awesome content in less than a year. Great job, everyone.

Happy birthday, Philosophy.SE!


Superuser color for followed links

Question: I can't seem to determine which questions I've browsed to on superuser based upon the coloring of the link.  As far as I can tell (maybe I'm color blind), there is no difference between the coloring of browsed and un-browsed links.  In contrast, on SO/SF/META, the coloring of browsed links is pretty obvious.
Answer: We actually did not have different color links for visited on Super User. An oversight. I just changed this, so visited links are now lighter.
Comment: Looks good to me.  Thanks (that was really quick).
Answer: Now that you bring it up I am seeing the same behavior. Overall it doesn't bother me (I've never actually been a fan of different colors for visited links myself) too much, but I can see why it could be an annoyance to other users.
Comment: I'm a newest-questions browser and I've relied on it to help me determine when I've pursed through the new items since my last visit.
Answer: This has been very annoying for me.  A lot of questions have similar titles and it is difficult to know if it is a question you've already looked at when the colors are all the same.
Answer: Most people after a certain age (usually 40-45 years) start having problems distinguishing shades of blue. Even though we all think it looks cool, with the internet community including this age group too (and increasingly, as we all get older), color schemes based on mainly shades of blue should be avoided. Especially light blue fonts on dark blue background, but also - as is the case here - similar shades of blue to distinguish properties of the content.

Superuser color for followed links


How is the Jedi mind trick not a dark side technique?

Question: How is the Jedi Mind Trick not a Dark Side technique? Isn't tricking another person's mind unethical? How can the Jedi use it and not become Dark?
Comment: By this argument, lightsabers should also probably not be in use.  Given the choice between slicing someone in half and convincing them with force mind control to leave you alone, I'd opt for the latter.
Comment: I'm sorry, I'm not seeing any duplication between this and honor/morals question. This isn't asking about honor or morals, it's asking about light side vs. dark side.
Comment: @Zibbobz - In general, Jedi use lightsabers purely for defence. Based on what I recall from various books involving lightsaber battles and/or guides on the subject, most of the common Jedi lightsaber fighting styles focus on avoidance of aggression and only allowed for opportunistic strikes in scenarios where there was no other viable option than to disable or kill your opponent.
Comment: @Richard K. I edited my question after considering your poignant analysis.
Comment: Why do you believe there's a correlation between light/dark and ethics? Both sides engage in ethically questionable actions.
Comment: Both sides use it to control those with weak minds.
Comment: I swear I remember there being another discussion about this, but I can't find it now.
Comment: I guess I was probably thinking of [this one](http://scifi.stackexchange.com/questions/10704/why-didnt-qui-gon-free-shmi-skywalker) which touches on it a lot too.
Comment: @phantom42 Meta-related: http://meta.scifi.stackexchange.com/questions/2816/why-was-this-question-about-hot-button-issues-in-star-wars-closed
Comment: possible duplicate of [What's the difference between the Light side and the Dark side of the Force?](http://scifi.stackexchange.com/questions/4085/whats-the-difference-between-the-light-side-and-the-dark-side-of-the-force)
Comment: ...isn't cutting someone to pieces with a lightsabre unethical?
Answer: Specifically focusing on the ability of the Jedi to alter the minds of others, the main principle is that this power (as with all Jedi powers) should only be used sparingly, with discipline and only for the accomplishment of the greater good.
The officially licensed "The Jedi Path: A Manual for Students of the Force" offers this advice to potential Jedi knights:

Affect mind, commonly referred to as the "Jedi mind trick"; can override the impulses of an undisciplined brain. This ability should be a temporary means to accomplish a greater good. It should never be used for profit or gain.
Alter abilities can be used to heal others, but also to injure. Both are Jedi abilities, though the latter must be used sparingly because the po-tential for abuse is so great. Among the Sith, Force injure was used without reservation to kill others from a distance.

The "Jedi Vs Sith : Essential Guide to the Force" also offers this advice (edited for brevity and clarity)

While it can be most useful in conflict resolution, affect mind must be used with restraint, almost always as a last resort, after exhausting less dangerous avenues that lead to peace. Yes, less dangerous, say I, for the power can easily cause permanent damage to a relatively innocent subject.
I need not lecture that you are responsible for your decisions and actions. How-ever, I will remind you that any course will leave a wake, and that even the smallest ripple can cause death. I also will remind you that you have yet to resolve that problem with the guard.
Before you answer, consider this: While the guard may prove to be an obstacle on your mission. he is also a living being. He may not be menacing by nature, merely an employee or servant. He may have a family, others who care about him. Had you met him under different circumstances. you might have discovered him to be a friend and ally.
Comment: @LieRyan - It's repeatedly stressed that the force is merely a tool. It's what you do with it that determines whether it's a dark side power. Your focus determines your reality.
Comment: Is Star Wars making the argument that mind control doesn't lead one to dark side but rather people leads themselves to the dark side. That line of reasoning certainly sounds familiar nowadays in certain other familiar topics.
Comment: @Richard: That is astonishingly similar to the Force-based religion the Potentium, which George Lucas tried to argue against himself, and took pains to force (*teehee*) later *EU* authors to discredit. Mind you, I'm a firm believer in Vergere's little doctrine. Also, you should note that Luke Skywalker expresses reservations about this power himself on at least one occasion. I unfortunately do not recall if it was *Shadows of the Empire*, or an early Zahn book. I've read both recently.
Answer: There will always be times when a Jedi will be at an impasse or a right spot. Obi-Wan needed the stormtrooper to not check his and Luke's ID in Episode IV. Luke Skywalker needed Bib to bring him in to see Jabba the Hutt in Episode VI. Rey needed to escape Starkiller base in Episode VII. Mind tricks allowed these light-side agents to serve the greater good without a show of force or unnecessary bloodshed, cruelty or torture, something that the Sith would be all too happy to do. As Darth Vader explains in
Star Wars: Darth Vader #1 to a gasping Jabba the Hutt:

Mind tricks are not of the Dark side. We prefer force.

*All sources used are within the new Canon.
Comment: Don't forget, Obi-Wan also used a mind trick to cause the drug dealer to go home and rethink his life.
Answer: I think this is a good example of how "light side/dark side" differs from "ethical/non-ethical." The defining feature of the light side is that it flows from calm and tranquility; the dark side flows from anger and hate.
Jedi doing mind tricks speak in a slow, soothing way. Presumably that suggests the mental state required: Calm, empathetic, focused on the other person's point of view (so you can bend it toward your own). Invariably the goal is to resolve a tense situation without violence or open conflict. That all points toward the light side rather than the dark.
Does that mean using mind tricks is always ethical? Heck no. I would say that you need extraordinary justification to use mind tricks, in much the same way that you need extraordinary justification to chop someone in half with a lightsaber - a thing Jedi have also been known to do.
The films suggest that the light side guides its users toward good and the dark side toward evil. But that doesn't mean a specific technique is only usable for one or the other.
Comment: Can you provide any sources for your answer, such as quotes or video clips? It is recommended that you support your answer with as much evidence to show proof your answer is valid and not just an assumption you've made.
Comment: I like this answer.
Answer: I think there isn't a fine line for this, and it all really depends on the circumstances. Using a mind trick as obi wan did to thwart storm troopers, is being safe. else the emperor would have continued his rule for another 500,000 years (exaggerated, of course)
Of course, it would be wrong to use a mind trick to get a weak minded person to strip and consent to intercourse. just saying.
Comment: Actually it's not a exaggeration. Sideous' "Grand Plan" all along was the discover the secret to cheating death and becoming immortal, something which his master almost achieved before being killed in his sleep with force lightning by Sideous. Has he succeeded in both overthrowing the Jedi and the Rebels, and learning the secrets to immortality, he would've ruled the galaxy for the rest of eternity, or at least until he had lost the will to live any longer. We all know the [gift of men](https://en.wikipedia.org/wiki/Gift_of_Men) is overrated.


How can I keep greengage jam green rather than orangey brown?

Question: How Cani keep greengage jam green rather than orangey brown?
Comment: Personally, I have only seen it green with large amounts of artificial color.  Lemon and such may help keep it more towards yellow than a deep brown like an apple butter, but I would be surprised if it color preservation is substantial.  Traditionally, this jam was made with less ripe fruit which would be more towards green, less towards yellow to try to not make an overly sweet jam which would also tend towards a less dark end product, but still unlikely to seem green without coloring.
Answer: It sounds like it is oxidizing so you need an antioxidant for the jam.  First I need to know what ingredients Greengage jam contains.  Then I can advise you on natural antioxidants to add (like lemon juice for avocados).
Comment: Plums may be too ripe, with low citric acid content. Either lemon juice, or citric acid, both of which are found in some Greengage jam recipes, should help with the oxidation problem.
Answer: The only way to keep the the green color you want would be to use a no-cook (freezer) recipe to make your jam. The process of cooking breaks down the chlorophyll in the plums, eventually changing it to a yellowish color.
For the geeky science explanation you can check this out The Why, How and Consequences of cooking our food


Options when go private

Question: What happens to options when a company goes private. For example, if I have a call option on Tesla right now and it goes private at 420/share, what will happen to my options?
Answer: You get force-liquidated with the go public price as reference.
I.e. if you have an option to buy at 400USD, you get 20USD (all per share).
Answer: When a stock  is converted into a right to receive a fixed amount of cash, its options will be adjusted to require the delivery upon exercise of a fixed amount of cash ($420 in your example).
On the date of the buy out, option  trading will end and all  out-of-the-money options will be worthless and all that are in-the-money trade at their intrinsic value.  For a call, the intrinsic value will be the stock's price less the strike price and for a put it will be the strike price less the stock's price.

Options when go private


Time travel novel with dragons and an old truck

Question: Looking for the title of a book likely published around 1980-1995 or so where the main character drives an old (1950s or 1960) pickup truck down a time travel "road" that others travel as well.  He is chased throughout the story by a dragon of some sort I think.  Cover showed the back of the old truck and maybe guns or a dragon tail.  Main characters were an old or older man I think, traveling with a younger man or boy. Not sure about that. The opening sequence has the older character stopped by some sort of time travel road policing agents as he is trying to take guns back to Sparta/Troy? to help them win a battle.
Comment: If you are back on the site, please click the check next to an answer so it is marked as solved. (They're essentially the same, but David's was first & he would benefit from the reputation.  I can't tell you which helped you the most, though.)
Comment: Yes, please mark one of the as "accepted". This will mark the question as solved and dish out some rewards! :)
Answer: Probably Roadmarks by Roger Zelazny.

From the Wikipedia summary:

The narrator and protagonist, Red Dorakeen, has vague memories of a place or time that is no longer accessible from the Road. He runs guns to the Greeks at Marathon, trying to recreate history as he remembers it in an attempt to open a new exit from the Road to his half-remembered place.
Comment: This is a little disappointing, actually. I bought a con t-shirt once with that image, where the road sign had been (I now see) altered to the name of the city the con was in. I suppose I should have suspected that it was a bootlegged image, since there wasn't an obvious credit. Hopefully I can now redeem myself by tracking down the story, reading it, and telling people about it when they ask.
Comment: That's a really strange cover image; it must be from a re-print edition.  (My copy has the cover pictured on Wikipedia.)  "A Night in the Lonesome October" was written 14 years later (1993 vs. 1979); I just checked.  (It looked so strange...)
Comment: @DavidW I grabbed the first one at Goodreads.  Matched my basic memory and I didn't really look at the blurbs or frame, honestly.  Looking into it, you're correct, it is from the 1994 reprint, but the picture is essentially the same as the 1979/80 original, just lighter and framed in blue.
Answer: Roadmarks by Roger Zelazny.  The cover has the blue Dodge pickup truck and the dragon exactly as you describe.

As noted in the Wikipedia article, early in the novel the protagonist is trying to run guns to the Greek soldiers at the battle of Marathon; that matches very closely what you remember as well.  (He's trying to push history back into a configuration he remembers, which includes the Greeks winning at Marathon.)
The younger man may be Red's son Randy (C Twenty Cleveland) who goes looking for his father with the help of the AI called "Flowers of Evil."
Comment: That is it.  Wow, that was fast.  Thanks.


What are the differences (and relationship) between the steps used to (1) validate a transaction and (2) confirm a block?

Question: On the Ethereum blockchain, what is the difference (and relationship between) (1) the process used to validate a transaction and (2) the process used to confirm a block? It seems that these processes are pretty autonomous since some blocks get confirmed with zero transactions. But a block can only get confirmed if all the transactions within it have been validated, right? I would love more clarity about similarities and differences between these two processes.
Comment: Perhaps my terminology is wrong, but I haven't heard of blocks being confirmed (validated/verified, yes). I have heard of transactions being confirmed (separate from validation) based on the number of blocks in the "winning" chain they appear in. Blocks are verified/validated before being appended to the blockchain. Are we referring to the same thing using different terms?
Answer: I can provide a high-level summary that will help things make more sense as you google around for the details.
They are separate concerns.
Validation is concerned with deciding if the transaction is allowed. For example, I can send a transaction that transfers all your ether to my account. Validators will notice that my transaction isn't signed with your signature, so it's not allowed by the protocol, therefore no state changes, and I loose all the gas I sent.
Other reasons to invalidate a transaction. Sender has insufficient funds, contract decided the input wasn't acceptable, contract decided the request wasn't acceptable.
Mining a block is a separate concern.
A block of transactions is a set of transactions in a specific order. Ordering is important because the network needs to determine an order for the transaction processing. Without consensus about the order of events, no consensus about the results is possible.
The challenge here is twofold. There is network latency, so nodes don't learn about pending transactions in exactly the same order. And, to be fully decentralized, the solution can't rely on anyone's clock because no one's clock is considered any better than anyone else's.
Miners order the pending transactions they know about and when they "find" a block they broadcast the solution to the network. This disambiguates the order of events so the network can reach a consensus about the order of events. PoW is like a lottery. The winner gets to "deem" that the transactions in the block unfolded in a certain order. They also get to decide which transactions (they may not know about them all, or the fees might be too low). Missed transactions will usually be processed in a subsequent block.
Confirming a Transaction
After the block with my (failed) transaction, there is a small possibility that a different miner will announce a block with a different solution. This will possibly contain the same transactions but in a different order, or possibly different opinion (byzantine fault tolerance) about validity. It means a block can be overturned by a better idea. Still, a new block arrives about every 15 seconds, so as these pile up the odds of older blocks being overturned becomes vanishing small. This is why it's customary to wait for a few confirmations for recognizing high-value transactions.
All together now:
My ridiculous transaction might be (say ...) the third transaction in a block with a result that I lost my gas. The network reaches consensus through the mining process that the transaction was the third processed by the network and the transaction was invalid and I lost my gas because of it. After a few more blocks arrive, we can be pretty confident we've seen the last word on the network consensus about my lame exploit.
Hope it helps.
Comment: Due to the network latency, nodes learn about pending transactions in different orders. Due to physics, we can't expect everything to be faster than everything else. Due to decentralization, no one's clock is any better than anyone else's, so we can't use them. The puzzle is a way to disambiguate the correct order of events inside a block. The miner that solves the puzzle first wins the privilege of announcing the order transactions are to be (were) processed. Additional details deal with the scenario when two or more miners announce a solution more or less simultaneously => eventual consensus
Comment: That was very helpful, Rob, thank you!  So, now I understand that the  validation of a transaction is basically an evidence-based process (i.e. establishing that there are sufficient funds, that the transaction is signed etc.).  And, so that is independent from whether or not it will get confirmed.  So, the confirmation of a transaction only happens when the block gets confirmed enough times?  Just wanting to make sure I got that right.
Comment: I want to check another thing... I'm also accurate that the confirmation of a block involves (1) solving the mathematical puzzle thing + (2) disseminating the solution to the network faster than others who may be solving it around the same time?  I'm still not really clear about the relationship between (a) ordering the transactions in a particular order and (b) solving the mathematical puzzle.  How do they relate to the confirmation process?
Comment: @RobHitchens: thanks for the wonderfully simple language used to explain this.

Any sources where I can read more about eventual consensus in case of 2 or more miners simultaneously solving/announcing a new block? I got to know that creates a fork in the chain which can be resolved by waiting for a set number of confirmations (6 in case of Ethereum from what I read -  but I could be wrong) - but what if the fork goes beyond that set number?
Comment: Proof-of-Work is one of those things to spend a little time seeing explanations from lots of viewpoints until it clicks. The "fork" you describe is correct. It gets resolved by the longest chain rule. As blocks stack up, node observe which chain has the most proof of the most work and that deem it to be canonical chain.
Comment: A non-obvious property that I think is important to grasp is that no transaction is necessarily lost when a block is rejected because, "hey ... we're following the other fork now". Both valid chains have valid transactions from the same pending mempool. In most cases, the chains have the same transactions in a different order.


Is there a relation between combustion instabilities and chamber pressure?

Question: Is there a relation between the combustion chamber pressure, and either an increase or decrease in both high and/or low frequency combustion instabilities. If so, how has this influenced engine design, and does this relation differ between different engine cycles, eg. pressure fed, full flow, expander cycle, gas generator?
Any graphs would be really great!
Comment: There are very few rocket engines that could be used to derive such a relation. Only engines using the same oxidizer and fuel may be used. The thrust should be equal but the chamber pressure  different. Different chambers and turbo pumps but similar thrust. Building a series of test engines to derive a relation would be very expensive.
Comment: @Uwe I hadn't thought of this but even so it is such a huge part of engine design I still would've thought even just some basic investigations would have been done
Answer: I'm not going to do this beautiful beast of a paper justice, so by all means, feel free to dig into it yourself.  It actually looks pretty readable, although processing all the math and theory would take me about an hour per page.  But luckily, the highlights are at the end:
For chugging (low frequency instability):

"4. The frequency of unstable oscillation increases as the steady state chamber pressure is increased (Figure 48)."

...

"8. When the chamber pressure is increased, the stability of the motor is improved.

The low frequency type of instability is found to be the predominating type in liquid propellant rockets operating under low chamber pressures and low injection pressures.  Under relatively high chamber pressures, high frequency modes of the acoustic type develop concurrently, and may become preponderant in some cases"

For screaming (high frequency instability):
The discussion and conclusion section doesn't explicitly link steady-state pressure to high frequency instability.  Maybe it's mentioned elsewhere in the paper, or maybe the relationship is insignificant.  The closest thing to an answer for your question that I could find is

"High frequency instability can be induced in a given motor by lowering the pressure in the propellant tank which results in a simultaneous decrease of the chamber pressure, the pressure drop across the injector, and the flow rate."

However, I interpreted your question as mostly focusing on steady-state chamber pressure, whereas that statement above sounds like changing pressure during operation.  I could be misinterpreting, though.
Comment: Great find! Thanks for the answer it covered all of my questions


Closest thing to a donut I can drink coffee out of

Question: One joking characterization of a topologist is someone who can't tell their donut from their coffee mug. As a novelty, I would very much like a food I can drink coffee out of. Does this exist? If not, what could I do to make it? It doesn't have to be anything like a donut, but if it is, that would be excellent.
Comment: All of the solutions in http://cooking.stackexchange.com/q/40024/67 can't handle hot liquids.
Comment: Thou shalt avoid using a preposition in a sentence on which to terminate with. Anyway, logically speaking, anything that could withstand hot liquids would also be hardly digestible.
Comment: What about a hollowed-out pumpkin?  Or does it have to be something that you can eat after you've finished the coffee?
Comment: @BlessedGeek I don't think temperature resistance or structural integrity have much to do with edibility.  Think of root vegetables for example.  That's also a made up nonsense rule; English SE has a good question about it if I recall correctly.
Answer: As far as foods that double as dishes, off the top of my head I could only thing of a bread bowl for soup. You could certainly drink coffee out of a bread bowl, but I don't think it will be enjoyable.
A bit of googling leads me to:

http://www.fastcoexist.com/1680504/a-cookie-coffee-cup-thats-easy-to-recycle-just-eat-it

The trick behind this is that it's a cookie lined with "special icing sugar" that works as a semi-waterproof barrier and an insulator. It will dissolve over a long enough time, though, and will sweeten the coffee as it sits in the cup. I can't find any information on when it hits stores, but it's a Lavazza product.
Comment: Ooh, nice. From the image, it doesn't look like it's topologically equivalent to a donut, but that should be fixable easily enough by poking a hole in the handle. (I don't require something topologically equivalent to a donut, but having the equivalence is a plus.)
Comment: Stipulate that it's equivalent to a [long john](http://www.amazingglazeonline.com/chocolate-long-john.php)? Though then you've got the filling to contend with...
Comment: Coffee and bread are delicious together, just drink the coffee first.
Answer: As long as you're content with single-use edible containers, a hard vegetable which can be eaten raw would serve. For example, you could drill a carrot to make a shot glass; if you get a big carrot then it would hold an espresso. The flavour imparted might not be so great, though: it would probably be better for vodka or other beverages which are known to mix well with carrot juice, because even if you dry the inside after drilling juice will continue to leach into it.
Repeated use would suffer from problems of mould, as well as from the inner surface becoming cooked.
Answer: As a child, if i was every lucky, i used to have hot chocolate and croissants on saturday mornings. One thing i would do is tear one of the arms off the croissant, dip it into the hot chocolate, and use it as a tiny drinking horn.
A quarter of a century later, we live in an age when humanity has the technology to deep-fry croissants.
It is surely not beyond the wit of man to put these two ideas together: make some sort of cup out of croissant dough, probably bake it a bit to give it some shape, then deep-fry it.
It won't be the same texture as a doughnut. It will, however, be topologically equivalent to a doughnut - a jam doughnut!
Answer: I'd attack this by making a cup shaped pastry (or some kind of hard cookie dough in a cup shape) and then sealing the inside of it with high temperature chocolate. You could then serve coffee in it as long as it isn't too hot to melt the chocolate.
Note that regular chocolate melts at too low a temperature, you'd need to shop around for the right product.
Comment: And because chocolate melts at temperatures between 30 and 33 Celsius, you are practically limited to lukewarm and iced coffee. Which makes it completely irrelevant to most coffee drinkers.
Comment: True, but there are chocolates with higher melting temperatures. See my edit.
Comment: I have never heard of such chocolates. I opened a question on them, maybe you could go in detail about them there? http://cooking.stackexchange.com/questions/43977.
Answer: This is probably as close as you are going to get, at least that I know of.
http://www.eater.com/2015/2/25/8106849/kfc-edible-coffee-cups-cookie-cups-buckets-fried-chicken


実名 vs 本名 connotation?

Question: I've seen both of these used about equally, and they seem to have similar meanings. Are they entirely interchangeable?
Answer: Both are translated as "real name" in English. According to 類語例解辞典{るいごれいかいじてん}, 本名{ほんみょう} is used as opposed to the name that a person uses such as a stage name or alias. 実名{じつめい} is used when one dares to disclose one's name.
The sentences below are examples taken from 類語例解辞典{るいごれいかいじてん}:

本名{ほんみょう}/実名{じつめい}を名乗{なの}れ。
  'Tell me your real name.'
実名{じつめい}入{い}りで記事{きじ}を書{か}く。
  '(person) writes a [newspaper/magazine] article in her own name.'
本名{ほんみょう}を偽{いつわ}る。
  '(a person) lies about their real name.'

Compared with 本名{ほんみょう}, 実名{じつめい} tends to be used in the sense of revealing/hiding the real name. For instance, the police make 実名{じつめい} of the suspect public or they hide 実名{じつめい} of the victim.
Comment: In example #2, the original and your TL do not match.
Comment: I didn't translate like this originally :/
Athough, the doer of the sentence is not specified in all the examples. So, the translation for the sentences can be various in a context.
As to #2, potential translations are:
1. I write an article in my own name.
2. I write an article that contains s X's real name.
3. X writes an article im his/her own name.
4. X writes an article that contains Y's real name.
(X and Y are dependent on the previous sentence.)
Answer: Yes, I agree with nominozomy about 70%. For these kind of stuff, you need to "feel" when it is used, when it should be used.
Although nominozomy quoted [実名]{じつめい}[入]{い}りで[記事]{きじ}を[書]{か}く。
'(person) writes a [newspaper/magazine] article in her own name.'
Regarding this I never came across wherever it is at work, or municipal registration stuff, or a conversation. And to me, personally, it sounds a bit strange.
In terms of frequency, 本名 is far more often used than 実名, at the official procedures, or in business, because as nominozomy said "Compared with [本名]{ほんみょう}, [実名]{じつめい} tends to be used in the sense of revealing/hiding the real name." And 実名 reminds me of some kind of criminal activities, though not for all cases.

実名 vs 本名 connotation？


Shield Encryption

Question: I have a general doubt on using encryption nature. Suppose I use shield to encrypt data and send some data as merge fields in an email template to other system, how is the encrypted data transferred / how does it appear to the receiver - in encrypted format or in original format? Say I encrypt name field of a custom object and use this in email template, name on record is John and if I choose * as masking character, in Salesforce it will be displayed as ****. When email is sent to other system, will the receiver see it as **** are plain text?
Answer: This is a very good question and this is one of the reasons we have given up on trying to support masking.
You can find more reasons here:
Encrypted data not in the encrypted format

Shield Encryption


Why do i only see QUIC and not UDP during capture in wireshark?

Question: I've been using wireshark and noticed that I no longer see UDP but QUIC, why is this the case?
Comment: I used udp as filter, but all the packets that I see are quic protocol
Answer: Wireshark uses dissectors and lua scripts to analyze and classify capture traffic (or parts thereof).  What is displayed in the Protocol field of Wireshark's Packet List Pane is the information returned that is most specific after analyzing the data and will determine how the data is presented.
If the UDP dissector is the most specific dissector for the captured data, than the Protocol column will show UDP. However many types of UDP traffic will be identified (SIP, RTP, DNS, etc).
The same is true for TCP traffic as well. Typically you will see this as HTTP, FTP, IRC, etc.

I've using wireshark and noticed that I no longer see UDP but QUIC, why is this the case?

In your case because the traffic has been analyzed as QUIC data. It may or may not be QUIC traffic; no program of this type is perfect, but Wireshark will be correct more often than not.
QUIC is one of the "newer" classifications, as it appears to have been added in 1.11.3/1.12.0. If you were using a version of Wireshark prior to these versions, the same traffic may likely have been classified as UDP (or another protocol).
If you don't want the QUIC protocol to be identified, simply go to the "Analyze" menu and select "Enabled Protocols" from the list. Find the entry for QUIC and uncheck the box.
Answer: QUIC runs atop UDP, so a QUIC packet is a (normal) UDP packet.
Wireshark currently treats all UDP packets to or from ports 80 and 443 as QUIC packets - even if they aren't.  Are the UDP packets in question going to or from one of those ports?  And are they, in fact, QUIC?
Answer: If you see QUIC, you are seeing UDP. Unless you are sending UDP segments without QUIC, you won't see only UDP.
From A UDP-Based Secure and Reliable Transport for HTTP/2 draft-tsvwg-quic-protocol-02:

QUIC (Quick UDP Internet Connection) is a new multiplexed and
secure    transport atop UDP, designed from the ground up and
optimized for


PCR related problem

Question: Recently, I have done a PCR of a region of human p53 gene and got faint band after that. Then I used that PCR product as input and did a nested PCR with same PCR condition, but now the specific band disappeared and only smear was there. Can anybody help me to solve the problem. Why that happened and what should I do to get specific band.
Comment: Can you tell us what the template DNA was in the first PCR?
Comment: More detail of both protocols would be helpful.
Answer: Ther could be different problems affecting your r salts. Maybe the primers you are using are not specific enough or your PCR condition are not optimal. I would first check the primers by blasting them against the human genome to spot mismatches. If your primers do not bind uniquely to your gene of interest then design a new pair. If the primers are ok, then I suggest you to run a grandient PCR (annealing temperature from 50 to 65 degree Celsius) to determine the optimal annealing temperature of your primers. These two steps usually solve 99% of my PCR problems, assuming that your template DNA is ok and at the right concentration. If even with the gradient PCR you can't find a good condition, the next step is to play with the buffer by changing magnesium chloride concentration and maybe adding betaine.

PCR related problem


Transformation of coordinate systems in ArcGIS Desktop?

Question: I am a Masters student and quite new to ArcGIS. I am working on a map and am a little confused about when to use transformation of coordinate systems/projections. I am using ArcGIS v10.2 and have a map with two coordinate systems: GCS GDA 94 and UTM GDA 94 as well as a basemap. I understand that ArcMap projects these on the fly, but I am wondering if I need to transform the GCS GDA 94 data to UTM GDA 94 to edit the data. By editing the data, I mean adding polygons as layers and using the AddIn Sampling design tool to add random points to these. I sometimes get warning messages from ArcGIS about this. I have read quite a few posts on Esri's site, but am still a little unclear. I need to export the final GPS points as UTM GDA 94 to transfer to my GPS.
Comment: Nicole, I answered this yesterday when you posted the same question to an ArcGIS blog. Summary: your data is using the same geographic CRS so no geographic/datum transformation is needed. The Editor will warn you because sometimes people do stupid things. If you're within the UTM zone, no worries.
Answer: If you go to the data frame properties and then the coordinates tab. Choose the coordinate system you want (lets say UTM) then there is the transform button at the bottom, click on that. You will see a FROM to INTO and then the Using, it's that Using drop down that offers up the actual transformation. I've never used what you are using so it may only have just one choice? A Google search is throwing up various threads and pages about it.


How to port function names from one exe to another?

Question: I have two 64 bit elf files for one program but with 2 different version.
IDA can resolve the function names in one of them while not for the other.
I don't have bindiff but I want an automatic solution like this tool if available
Answer: You can try and use Diaphora. It is open source, and is probably the best Bindiff alternative out there.
That said, be aware that binary diffing might fail in many cases regardless of the tools used.
Comment: In addition to Diaphora, here are several more diff'ing tools: http://www.woodmann.com/collaborative/tools/index.php/Category:Executable_Diff_Tools


If a ball carrier falls to the ground, how many seconds will the umps allow the clock to run?

Question: If a ball carrier falls to the ground, and the other team wishes to run the clock because they are leading, how many seconds will the umps allow the clock to run?
Comment: Until the team snaps it or until that team, or the other team calls a timeout
Answer:
If a ball carrier falls to the ground, how many seconds will the umps allow the clock to run?

The referees will let the play run until they determine that the ball carrier is making no immediate effort to advance. At this point, the play is blown dead, and the clock will continue to run until an event that stops the clock takes place (eg, timeout, delay of game, the result of the following play stops the clock).

Rule 7, Section 2, Article 1-d-1 states:

An official shall declare the ball dead and the down ended:
when a runner declares himself down by:
falling to the ground, or kneeling, and clearly making no immediate
  effort to advance.
Answer: It all depends on the situation. If the play goes down out of bounds the clock will stop, if he falls to the ground, let's say in the middle of the field, then the clock will keep on running till somebody calls a timeout or if somebody went out of bounds.
Answer: Up to 40 seconds.
NFL Rule 4, Section 6, Article 1 states:

It is a delay of the game if the ball is not put in play by a snap within 40 seconds after the start of the play clock.
Comment: Thank you.  I thought that the ref would declare his forward progress was clearly stopped, declared the ball dead, and the play was over.
Comment: The question reads as a ball carrier during play falling, not a pre-snap delay of game. This doesn't answer the question as it is currently written.
Comment: Let me flesh this out.  The score is 20-18 with 01:35 on the clock.   The ball carrier's team has 18 facing a first and ten.
Comment: @KenHenkel That doesn't flesh anything out. Has the play stopped (ie, a dead ball) or is the play in progress (ie, a live ball)? If the play has stopped, the refs will allow the clock to run until the ball carrier's team snaps the ball, calls a timeout, or incurs a delay of game (after 40 seconds, the duration of the play clock, as this answer interprets). If the play is in progress, the refs will allow the play to continue (while the clock runs) given the ball carrier is [making an effort to continue the play](https://sports.stackexchange.com/a/13964).
Comment: If the fallen ball carrier is making no move to declare the ball dead, he may have a concussion.  I think the refs would not allow the clock to run 40 seconds.
Comment: Or he may be delaying the game. What may be has no relevance compared to what is, and what is happening is a player making no effort to continue the play, so the clock will run for 40 seconds unless a specific reason for stopping it is available.
Answer: once the play is over the refs will stop the clock asap if there is a reason to such as a timeout or an incomplete pass (if they don't do so on time they will likely ask for the clock to be reset to the correct position), otherwise the clock won't stop at all they just keep going (and the offense has 40 seconds to start the next play).


Training while predicting on dataset

Question: I have been trying to figure out whether if I train a model and then while predicting is it possible to train images too just like humans
Somehow converting valid images to the dataset by asking us when an object is shown
Like the Google Photos somehow they ask us if they predicted a face correctly and then reinforces on it
Answer: Yes, this method of training a model is commonly known as online learning and specific learning algorithms have been designed for this purpose, such as, Stochastic Gradient Descent(SGD). As opposed to Batch Gradient descent, which computes gradients over the entire training set at each step, the SGD algorithm computes gradients for individual samples and updates the model's parameters.
The online learning strategy is not specific to Reinforcement Learning(RL) methods but is also suitable for the broader classification of Machine Learning algorithms. Suppose, we are given a simple model pretrained on a large Face Recognition dataset, and wish the model to continuously adapt to new faces, we may keep feeding in the new input images with their correct labels (obtained from feedback), as they appear, and apply SGD to incrementally update the model. To go about this using an RL based approach, we may penalize the model with negative rewards for every label misclassified and update it.
Comment: During prediction, if we are using the camera to detect the person instead of uploading picture to predict. Can we still make the algorithm learn? And what if the model would be detecting incorrectly
Comment: Yes, a camera can be thought of as a device capturing a sequence of images. As long as there is some mechanism to tell that the model detected incorrectly, you should be able to make it learn.

Training while predicting on dataset


How is the pH scale constructed?

Question: How is the pH scale constructed , I mean the strength of an acid is determined by its pKa value and this one can be determined in different solvents if water doesn't suits it but how do you determine the pKa value of a substance in water after you have found the value of its pKa in another solvent ? Also I don't think I quite understand why the pH interval in water is running from 0 to 14 (I know that it has to do with the leveling effect but when you take this scale for other solvents the starting value can be different from 0 , if I am not mistaken for liquid NH3 the starting value is 5 ) can someone explain to me from where does this values come from ?
Comment: First of all the scale in water doesn't go from 0 to 14, it can extend beyond those values (values of -2 to 16 are possible without too much effort in a lab). The scale in liquid ammonia is much larger, covering over 30 units. See [here](https://chemistry.stackexchange.com/q/6997/1499) and [here](https://chemistry.stackexchange.com/q/5047/1499), as well as several other Chem.SE posts tagged with pH.
Answer: The pH is determined experimentally with a glass electrode. A glass electrode is a small glass tube limited by a thin membrane and filled with an aqueous KCl solution with a silver electrode inside. There is also a similar silver electrode out of the tube, in a compartment in contact with the outer solution. When you dip a glass electrode into an aqueous solution, the experiment shows that the tension E read between the two electrodes is proportional to the logarithm of the H+ concentration of the external solution. It is :  E  = Constant + 0.059 pH. The Constant depends of the particular glass membrane.
And the experiment shows that pH is -log[H+] at low acidic concentrations, and is measured as

7 in pure water,
3 in 0.001 M aqueous solutions
2 in 0.01 M aqueous HCl solutions,
11 in 0.001 M aqueous NaOH solutions
12 in 0.01 M aqueous NaOH solutions.

These values are in agreement with the usual expression : pH = -log[H+], or : pH = 14 - log[OH-]. At higher concentration, the measured pH values are not exactly equal to the logarithm of [H+]. The measured pH is said to be the logarithm of the "activity" of H+.
The pH does not go only from zero to 14. It may be smaller than zero in concentrated solutions of HCl and of H2SO4.
In non-conducting solutions, the glass electrode does not give any stable values. The measured tension is fluctuating without any reason and can be ± 3, 5, 10 or 0, and this changes constantly.
Comment: Maurice's great experimental depiction clearly notes the measurements are created in DILUTE conditions. Otherwise, the 'activity coefficient' is important which is a function of ion charge, ion size and ionic strength. So, in the presence of high ionic concentrations of salts like FeCl3 or CaCl2 with a large ion charge, even dilute HCl can apparently 'act' as a much stronger acid due to the activity coefficient which is applied to [H+]  to determine the pH (see  http://www.csun.edu/~hcchm003/321/321100313.pdf page 4).
Answer: The pH+ scale is a logarithmic scale, based on the number of $\ce{H+}$ ions available (with the caveat that $\ce{H+}$ is theoretical, it may be $\ce{H3O+}$ or other ionic species). I.E., in water at ~300 K, ~10−7 mol dm−3 of the positive and of the negative ions exist, a pH+ of 7 (the negative exponent).
For a strong acid, virtual all, 100%, of the molecules are broken into ions, e.g. $\ce{Cl-}$ and $\ce{H+}$, so the pH+ is 0 [10−0 = 1].
Note that at different temperatures, water may be more or less ionized, so a neutral pH+ is not necessarily 7. At its boiling point, "neutral" is about 6.14.

How is the pH scale constructed?


Database hacked - random posts are modified

Question: I have noticed that part of my posts was modified. Sometimes the original post is mixed with random words consist with random characters or content is replaced by spam. I have a lot of posts and I am not able to compare them manually but I have a database dump as sql files which I make sometimes. Is there a way to compare backup and current version of database to detect differences and replace spam?
I already tried to compare sql files as text but it's time-consuming and my computer is too slow.
Answer: It's possible that the random stuff is not in the database; your answer doesn't make that clear. There could be some modified WP files that are inserting text in each displayed post.
Recovering from a hacked system is time-consuming, but can be done. Short list: update WP/themes/plugins to latest versions. Check the htaccess file against a default one. Change credentials on all WP accounts (set up a new admin account, sign in as that new account to make sure it works, then reduce privileges on the old 'admin' account). Change credentials on FTP and email and hosting accounts. Look for changed PHP files. Check the wp-config.php .
I wrote about the above in my blog (more for my use, since it is not visited by many) here: http://securitydawg.com/recovering-from-a-hacked-wordpress-site/ . There are other places that have similar info; mine is just things I've figured out over the years).
As for comparing databases, that's a complex item, since there will be much complexity to any SQL statement that would compare data contents in two separate WP databases.
I wrote a small program several years ago to compare file hashes with previous 'runs' of the program (each file's hash was stored in a table, then compared with a current runthrough of the program). That won't help you here, but it is one way to keep track of file changes.
If you can figure out when the problem occurred, your hosting place might have an old backup of the database and files they could restore. But that would erase any changed to the blog since then, so that might be a last resort.
Again, you can recover from this. It will take some time and effort, though. Good luck.


TIFFs with Worldfiles to GeoTIFFs

Question: I'm looking for a way to convert several TIFFs with Worldfiles to GeoTIFFs.
Is there an option using ArcGIS or Python (Arcpy)? What is the best option you could recommend?
Comment: Most "What is the best" questions are not a good fit for the GIS SE "focused question / best answer" model.  The [Don't Ask](http://gis.stackexchange.com/help/dont-ask) page sets a high bar for fundamentally subjective questions, which would require a great deal of research and wordsmithing (far more effort than Export... Raster to Different Format, or downloading libgeotiff. or installing GDAL)
Comment: @Vince this is a very specific ArcGIS question, no research is required. Every question with "best" doesn't need to set off an alarm.
Comment: Caution: I've had strange bugs in the past where the root cause turned out to be Geotiffs with world files where the registration in the geotiff header conflicted with what was in the world file.
Answer: Have you tried ArcMap, Conversion Tools, Raster Toolset, Raster to other format? choose tif as the output. Also, I remember from ArcMap, table of contents, you can export an Image, tweak the settings. It seems ArcGIS prefers to create a Geotiff instead of tif/world file. Also with Geotiff you can assign a spatial reference.
Answer: I would recommend you to georeference the images with ArcGIS or QGIS in order to avoid distortions. If you save the outcome a world file will automatically produced next to the corrected TIFF image
Comment: the tiff files are already georeferenced since they have a worldfile, i would like to change the tif (with the worldfile) to a GEOTIFF using ArcMap. Is there a tool or function available?
Comment: In that case you could stick to the explanations given here: http://gis.stackexchange.com/questions/87642/how-to-convert-a-tif-with-tfw-to-a-geotiff

TIFFs with Worldfiles to GeoTIFFs


Can Copay iOS wallet sync with the Copay oSX wallet?

Question: Can Copay iOS wallet sync with the Copay oSX wallet? Hoping to use the same wallet across both devices.
Answer: Yes, that's possible. Assuming you first created the wallet on your iOS and want to access it on macOS:
1) Open CoPay on iOS
2) Go to "Settings"
3) Under "Bitcoin Wallets" there's "Personal Wallet", click it
4) Choose "Backup" under "Security"
5) Write down the 12 words seed
On your macOS:
1) If you have just installed CoPay, it'll ask you for seed. You can type it, and then you're done.
If you already have CoPay installed:
1) Press "+" next to "Bitcoin Wallets"
2) Choose "Import Wallet"
3) Type your recovery seed


How to re-enable my Facebook account?

Question: My Facebook account got disabled without any prior warning. I have been using account for 3 and a half years without any issue.
I have raised several appeals to Facebook help center, even emailed them on appeals@Facebook but got response as You've reached us at a channel that we don't support.
Please suggest me how to get my account enabled again. How do I reach the Facebook team directly?
Answer: Submit your appeal via their Appeals Contact page.

How to re-enable my Facebook account?


How can I transfer my all contacts from old HTC Wildfifre android 2.1 to LG Optimus Vu

Question: I just want to transfer all contacts from old HTC Wildfire with android version 2.1 to new LG Optimus Vu with android version 4.0. I have used different apps but still I am unable to transfer contacts and an unexpected error occures. Another issue is that I can't move contacts to SD card because LG Optimus Vu does not supports SD card. Please recommend a simple and easy way or an app which is helpful to transfer contacts to the new LG optimus Vu from HTC Wildfire.
Answer: Just a few steps:

Open the contacts app on the Wildfire
Tap the menu button, select to "Export" your contacts to SDCard. This will result in a 00001.vcf file on your SDCard.
Now use any way you like to get the exported file to the Optimus:

Mail/GMail it to your account
Send it via Bluetooth
Copy to your computer, and then to the new device's internal SDCard
...

On the Optimus, open the contacts app
As above, use the Export/Import feature to import the .vcf file

If in step 3 you chose to Mail/GMail the .vcf file, you most likely will be able to open it directly from the attachment, which should cause it to be offered for import into your contacts app (I never tried that variant, so I'm not sure about it).
Answer: I installed Contact Sync and exported all my contact data and groups to a single .vcf file, afterwards I mailed it to my mail account and then downloaded it on my new phone and there imported it with the same app which I used for the export. This did the trick for me.
Answer: The simplest way would be exporting all contacts to Google account and then Sync it in a new device.


Penetration depth and weld deposition rate in Welding

Question: What factors affect the penetration depth and weld deposition rate in arc welding?
How does polarity affect the penetration depth and weld deposition rate?
My lecturer said that penetration depth is higher when using straight polarity when compared to reverse polarity.
But I've read in a textbook that it's the opposite.
Comment: Adding your own understanding of the process and any research you've done on the topic will help this from getting closed or put on hold.  We generally frown upon "go find me answers" type of questions without first seeing the effort you've put into the topic.
Answer: Quick answer, you are both right and wrong. Arc Welding has many types and for Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW), Flux Cored Arc Welding (FCAW) and SAW processes electrode positive polarity increases depth but for Gas Tungsten Arc Welding (GTAW) electrode negative polarity increases penetration depth. I'm not at the office so can't give reference from books but here is a page from Lincoln Electric .
Comment: More heat is generated at cathode than anode. Heat increases fusion depth. For GTAW more heat is needed at torch. Please check TWI documentation for example this page http://www.twi-global.com/technical-knowledge/faqs/process-faqs/faq-when-manual-metal-arc-welding-which-electrode-polarity-should-i-use/
Comment: Can you please explain how polarity influences penetration depth?
Answer: The practical effects of polarity of quite complex and depend on the process.
In a sense TIG is where the 'pure' effects of polarity are clearest as the arc creation is entirely separate from the filler feed. Here DC- (electrode -ve) is used for most metals except for aluminium and magnesium alloys. This polarity puts the majority of the energy into the weld puddle which is both more efficient and helps prevent the tungsten electrode from overheating. For aluminium the problem is that the thick, stable oxide layer needs to be cleaned off as welding progresses lest it contaminate the weld. Here reverse polarity is used as the electron flow tends to rip the oxide off the surface. You can actually see this happening in a TIG weld and a fresh weld will have a 'frosted' area around the weld bead.
In practice most modern machines now use a modified AC current for aluminium as this allows more adjustment of the arc properties. Specifically the balance between +ve and -ve current flow balances cleaning effect with electrode temperature and adjusting the AC frequency controls the width of the arc (which in turn affects penetration). The most sophisticated machines also a range of different wave-forms (square, sine, trapezium, triangular etc) which also affect penetration and heat distribution. Note also that in AC TIG the end of the electrode will melt and form  a ball slightly larger than the electrode diameter the fast cycling AC stops it from falling off into the weld. In DC welding the tungsten should not melt at all.
In MIG welding the fact that the filler wire is also the electrode means that heat is transferred to the puddle in a different way and the shape and shape and size of the metal droplets formed is very important. This favours putting more heat into the electrode as it is constantly melting and physically transferring that energy to the weld puddle in any case. So solid wire MIG welders conventionally run with reverse polarity.
In MMA things are more complex again as the composition of the electrode coating interacts with the arc polarity and the results are really a function of the particular electrode type and most electrodes will have a recommended polarity.
This subject is also further confused by the fact that conventional current is actually backwards in its sign convention compared to the rest of physics (ie the actual flow of electrons is from -ve to +ve) which doesn't make this any easier to understand.


Term for a goodbye that takes a long time

Question: Like https://english.stackexchange.com/questions/30115/is-there-an-english-phrase-for-an-inability-to-actually-leave-already , but for Japanese. You're on the driveway, you're saying goodbye ... but you engage in conversation for another half an hour. Is there a term for such a phenomenon in Japanese?
Answer: I cannot think of a single word or phrase that every native spekaer would agree on, but you can expect to hear us say:
Noun Phrases:
「帰{かえ}り際{ぎわ}の長話{ながばなし}」, 「帰り際のダラダラ話{ばなし}」, etc.  ("a long chat at the time of departure")
「話」 is pronounced 「ばなし」, not 「はなし」 here.
「ダラダラ」 is a perfect onomatopoeia to use for dawdling.
Verb Phrases:
「帰り際に長話(を)する」,「帰り際にダラダラと長話(を)する」, etc.
Comment: I think you may have meant "dawdling", not "doodling".
Answer: Though not a "set" phrase, I use the following a lot to describe something like that:
名残{なごり}惜{お}しくて話{はな}し込{こ}む (to talk a while, feeling reluctant to part)
名残惜しい means reluctance/regret to part. Note that this refers to one's feeling, meaning "one feels bad to part with this person/place", so you couldn't use it like "During the protest, the demonstrators were reluctant to leave".
Note that 1) this works either way (for the person staying or for the person leaving) and 2) doesn't really carry the negative connotation as that link you posted.


Granularity of content types

Question: Let's say you want to have a set of multimedia galleries, that contain a texts, photos and some youtube films. At the phase of creating content types, I can imagine few approaches. For example - we can create the whole gallery as a one content type, with few optional multivalue fields, or we can create separately content types for photo gallery, separate content type for texts, and all that would be linked by using taxonomy, or we can go even more granular - with content type for ONE photo, ONE text etc, and all that would be linked with each other by taxonomy. How granular content types should be and what are advantages?
Comment: TO answer this question we need full technical requirements for this site :)
Comment: This question is more general - you can interpret it: how granularity of content types relates to requirements for the site. :)
Answer: As Eugene Fidelin said, we'd really have to have a better feel for the site in order to give you the best advice. It depends - will each gallery have the same fields for each entry? Or does one gallery have videos while another does not? However, I will try to do so anyway.
If there are only a few galleries AND they differ in their fields, I would create a content type for each gallery entry and use them to populate a page with a view. I would do this because otherwise you're going to have to create a single content type with each type of field used by every type of gallery entry, and then for each one you're going to end up having a bunch of empty fields since they are used by the other types of entries.
However, assuming each gallery entry across all galleries has the same fields for the most part, I would just create one content type for gallery entries and then use taxonomy terms and then just use radio buttons to specify what type each entry is (so you might have Animals, People, Places, etc.) and then have views for each type that just filters by the taxonomy terms.

Granularity of content types


my chest freezer is going out.

Question: Thermometer says 30 degrees and has for about a week. The corn on the bottom shelf looked terrible and was pitched. Most of the meat was thawed but looks ok, which I plan to cook and refreeze. Green chili's, some were partially thawed some completely thawed. Should we refreeze? Are they ok to eat? Color is good on them.
Comment: 30 degrees on what scale?  Farenheit?
Comment: @SAJ14SAJ Yes, I'd assume 30F. 30C wouldn't make much sense, and it'd be a lot worse than just "mostly thawed". (Plus the OP's from the US.)
Comment: At 30F, it's not going. It's gone. You're holding around freezing as the ice decrystallizes. Once it finishes melting,  it'll continue climbing to room temperature.
Answer: Derobert's inference that your freezer is fully broken is almost certainly correct.  30 F would be about the temperature you would expect inside as the frozen food thaws.
So for some period of time, what you have had, in effect, is a refrigerator, not a freezer.
The question is, for each individual food in the freezer, would it still be safe if held at refrigerator temperatures for a full week.
You can get good estimates for many foods from these sites:

Still Tasty
Eat by Date

I would discard foods that are beyond their good life, or foods that would not be palatable when frozen, thawed, and then refrozen.
In the specific case of the green chilis (I am guessing whole), Still Tasty says about one week, so you are on the border.  You should use or re-freeze them quite quickly.  On the other hand, they have already sat for a week, and suffered the degradation from one freezing cycle.  As chilis are not normally terribly expensive, it may not be worth keeping them.

my chest freezer is going out.


Great Sphinx photo from WW2 shows a big platform under the chin

Question: This photo is in a TV documentary about World War 2 in Africa.  I see a large square platform build of bricks that goes right up to the chin.  What is this and why was it removed?  And why is nothing ever written about this in histories of the Sphinx I find online?  I seriously doubt it somebody would fake a photograph like this for a WW2 documentary.
Comment: @drewbenn Seems like you have enough to convert your comments into an answer.
Comment: More images [here](https://www.ww2online.org/image/sphinx-statue-egypt-circa-1944).
Comment: I wonder where they put the Thutmosis IV [Dream Stele](https://en.wikipedia.org/wiki/Dream_Stele)  while that support was there.
Answer: The structure you see is made of rock and sandbags, to protect the Sphinx from bombs as World War II fighting drew near the area. Life magazine reported in 1942 that,

the Egyptians have partially covered [the Sphinx] up.... From its base
  they have built a pile of rock. On top of that they have put a pile of
  sandbags, neatly tucking them in around the statue's chin to protect
  the weak limestone neck and face against breakage if a bomb should go
  off nearby.

Ironically, this protection was necessary after nearly two decades of excavations. From 1925 to 1936 Emile Baraize (beginning p.40) dug out the sand around the Sphinx and installed walls around it to keep the sand away, and found several temples and a Roman-era viewing platform. Baraize also took over 200 photographs during his excavations but I haven't been able to find an online archive of them. Selim Hassan took over after that and immediately razed Baraize's protective walls and continued the excavations and investigation.
Comment: Thanks for the explanation.  Looks like this site has good researchers.  What is your opinion on why the nose is gone?  Is it the Sufi Muslim leader who chiseled it off because his people were starting to worship the old gods again?


If everything is decreed in our life already then what's the point of making Dua?

Question: I read somewhere that only Dua can change the qadr and it is always encouraged to make Dua to Allah for every need, in every situation. But today I have learnt some mufti saying there are two types of qadr, ones that are absolute like time of birth,death n marriage. And these cannot be changed through Dua. Then if a person say for example, make Dua for a long life what would happen? Or, if a person makes Dua to marry a certain person/ person with certain qualities would that have no effect? I mean if these things falls under the category of absolute qadr on which Dua has no effect then why should people make Dua about them?
Comment: As you said, everything is already decreed. This means you making the duas was decreed and it will only be answered if Allah wishes to.
Answer: I think everything falls under absolute qadr which is written in Loh-e-Mahfooz with Allah (SWT). Which is your birth, death, rizq, siblings, spouse, kids and the main events that pretty much everybody agrees too but my personal opinion is that i think everybody's QADR is like a tree with a lot of branches and at the end of every branch is a fruit. There is a trunk in the middle that has a fruit at the end too. The fruit is the death which we have to get no matter what. The branches are the routes we take to get to the fruit of death the trunk is the right way which ALLAH (SWT) wants us to take but when we don't do that, then ALLAH (SWT) already knows that we will do this because of the free will so ALLAH (SWT) already decided if i do this then the result and consequences will be this and so on.
Means all the angles of each and everybody's life is already written and decided, all the aspects of life are all decided we are just highlighting the path we are taking to get to the end.
Answer: Maybe what is pre-destined is supposed to be in consequence of your Dua'a!


Is coroutine as good as a delay() function

Question: I'm new to Unity and I was learning the usage of coroutines.
Is calling a coroutine as good as a delay() function?
Does Unity have a delay() function?
Comment: Can you show us an apples-to-apples comparison of the two ways you're thinking of implementing your feature? Right now it's unclear what you have in mind with `delay()`. There are lots of ways to create a delay, and other than locking the main thread, they'll tend to all work similarly enough, so we need details to understand the specific differences for your case.
Comment: I've used Coroutines in the past and had no issue performance-wise. Is there something that you are worried about using them?
Answer: ratchet freak's answer is an excellent explanation of the differences between using Thread.Delay() and coroutines in Unity. To address your second question, I suspect what you're looking for is WaitForSeconds.
From the documentation:
public class WaitForSecondsExample : MonoBehaviour
{
    void Start()
    {
        StartCoroutine(Example());
    }

    IEnumerator Example()
    {
        print(Time.time);
        yield return new WaitForSeconds(5);
        print(Time.time);
    }
}

However, be aware that this example just starts the coroutine, it doesn't wait for it. For example, say you had some code in the Start function after the call to StartCoroutine. That code would get executed immediately, not after 5 seconds as you might expect. If you wanted to wait until after the the coroutine finished, you would have to either call that code from the coroutine, or set a value that gets checked somewhere else (like in Update), or wait for it inside another coroutine, etc.
For a simple timer, that can get messier than it needs to be. To circumvent that clutter, I like to use this free async/await library, which allows you to write code like the following
async void Start()
{
    print(Time.time);
    await new WaitForSeconds(5);
    print(Time.time);
}

Which does logically wait for the WaitForSeconds to finish before executing the code after it, without suspending the entire thread. In my opinion this is a much cleaner alternative to Delay(). Of course, async/await has its own gotchas and can be a little confusing if you've never dealt with it before. You can read more about using it with Unity here.
Comment: You can write code equivalent to the second example without an extra library like so: `IEnumerator Start() { ...yield return new WaitForSeconds(5);...}`
Answer: The problem with delay() as traditionally implemented (stopping the thread until it can continue again) means exactly that, it stops the thread and it cannot do anything else.
One underappreciated feature of unity (and in fact most game engines and gui frameworks) is that most of the main logic is executed on a single thread. This makes programming a lot easier as by default you don't have to deal with hairy multithreading.
However this means that if you don't allow that thread to continue working on other tasks (including stuff like taking input, updating the screen etc.) the entire program just stops responding.

But you still need some way to pause a set of actions action and resume it later.
This can be done explicitly by splitting the sequence of actions up in multiple sections and scheduling those to run at the correct times using timers or the update function that gets called every frame (which then dispatches to the correct section when it's ready for the next step) or implicitly by using the built-in coroutine system.
The coroutine system takes the yielded value and uses that to decide when to resume it. One possibility is a fixed delay or a conditional wait.
So the core system has a list of running coroutines along with their last yielded value. It then loops over those yielded values and tests whether to resume it. I like to believe that that one my previous post inspired this system.
Comment: Hmm... your previous post is from 2013, but Unity already had Coroutines in 2012, did it not?
Comment: @DMGregory Maybe, I wasn't that involved in that ecosystem back then. And I certainly cannot prove that my post actually inspired anything. AFAIK it did coincide with its rise in popularity.


What should I do when the recommender is not replying?

Question: I am applying for Ph.D. in US universities. I already applied in some places and suggested my recommenders name as well. Now one of my recommender (who previously wrote a recommendation letter for me) is unreachable. I mean I wrote her earlier and she gave me permission. Also, I had a copy of her letter which she sent me earlier. I wrote her emails but she did not respond.
Now my question is can I ask the universities (where I applied) if they will accept the letter from me as my recommender is unavailable at the moment? If I have to ask, whom should I ask? The graduate program coordinator or the graduate office? Will it make a negative impact on my candidacy?
(All my application papers, other two LORs have been submitted, only this one is left)
Also, it is quite impossible to manage another recommender as the university is closed and the deadlines are nearer.
Comment: Can you ask her department head (or secretary) why she might not be responding and, perhaps, intervene?
Comment: She is the department head. And as the university is closed due to covid, so it's quite impossible.
Comment: Did she give you a general permission to list her or did you get approval for the specific application before? This isn't clear to me here - it might turn out badly when she is contacted and doesn't agree to having her letter included in this particular application.
Comment: Yes, she gave me permission for the specific school as well.
Comment: The department must have a secretary, right? Get in contact with them. They may be able to reach your recommender for you. It may even be acceptable to the school for the secretary to submit the letter on behalf of her boss. (This is not uncommon.)
Answer: I would do a couple of things.
First, see if you can quickly organize a different recommender. Maybe futile, but it might work. Long term it might be useful to have a backup in any case.
Second, but simultaneously, inform the university to which you are applying that you can't reach the recommender and that Covid may be the reason. Tell them you have a copy of another letter from this person and ask for their advice on how to proceed. Give the name and email of your recommender, I think.
I suspect that people will be reasonable, given the general disruption. It shouldn't reflect badly on you if you do due diligence in getting recommendations. They may even be a bit "soft" about deadlines for such things. Note that admissions to doctoral programs is normally handled by people, not machines, and the people are all facing various kinds of disruption.
Finally, note that you not getting feedback from the recommender doesn't necessarily mean that they aren't otherwise doing their part. There may be a lot of reasons for not replying, many of them valid.
Comment: Do the second thing also. Ask for advice and add, as well that you have another recommender.
Comment: @Buffy- I have managed a different recommender (who is a kind of collaborator or you can say indirect supervisor and we published a paper together). Now my concern is none of my recommenders are academic (I mean where I did my bachelor, but my previous recommender was).
Comment: @Buffy-And I have a copy of her LOR which she sent me a few months back. As I already have her permission to use her name and also she gave me the LOR by herself so I was thinking what if I send it to the graduate office too by myself and explain to them that she's unavailable at this moment but I have her permission. Do you think this is a good idea? or I should drop the idea?
Comment: @Buffy-The graduate office accepted the letter that I sent to them. No need to add the new recommender. Thanks a lot for your kind help.


How much cake batter to make two 6"x2" cakes?

Question: I have two 6"x2" cake pans, and am wondering how many cups of a box cake mix batter I need to put into each pan?  Thank you!!
Answer: It depends upon how thick you want it. A 6"x2" rectangular pan, filled 1" deep will obviously contain 12 cubic inches of batter. 12 cubic inches = .83 US cup. So, to fill both pans to a depth of 1 inch, you would need 1.66 cups. To fill both pans to a thickness of 1.5 inches, you would need 2.49 cups. To fill both pans to a depth of 2 inches, you would need 3.32 cups of batter.
That's a 6X2 inch rectangle, of indeterminate depth, which is how I interpreted your question. A round pan with a diameter of 6 inches would hold 28.3 cubic inches of batter for each inch of depth. 28.3 cubic inches equals 1.98 cups.
Here's a conversion site for cubic inches to cups.
A 6"x2" rectangle is an odd shape and size, so I included an answer to another possible interpretation of your question. Please comment, especially if you don't feel that I've fully answered your question.
Comment: Your calculation here uses batter depth, but I assume that the OP wants to achieve a certain sheet thickness, and the starting depth of the batter isn't important. Indeed, depending on the batter, there is a lower boundary of sheet thickness (the cake always breaks if you try to make it thinner) and an upper boundary of sheet thickness (the cake doesn't bake in the center). Somebody who works with box mix frequently will know these boundaries, and know the rise factor, so could give an estimate of the usable range.
Comment: @rumtscho I'm kind of assuming that the OP knows the depth of batter she wants, that she has made the cake before. It is the depth of the batter is the primary variable to determine the thickness of the sheet. I understand the question to be asking how to convert this measurement that can be expressed in cubic inches, to cups.


Can I say that "his experiments are doubtful"?

Question: I would like to express the fact that I don't have confidence in what a scientist has told me concerning an experiment he has led. Can I say that "his experiments are doubtful"?
Comment: I probably wouldn't be doubtful about the experiment itself.  It's more likely that the *results* of the experiment or its *methodology* would raise doubt.  To consider the experiment itself to be doubtful, I would ask for more information about the motive/rationale, or what the experimenter was trying to determine; if that doesn't make sense, only then would I consider that "the experiment is doubtful".
Comment: Why are you using "experiments" when you are only doubtful about *one specific experiment* of his? Or am I missing something?
Comment: Let us say there are several experiments. My point is just to know if doubtful can be used to qualify an experiment, to say that they don't seem serious.
Comment: @JCLL - This point should be there in the original question. :)
Answer: Doubtful may be used in several ways:

Something that is causing doubt;
A person who is unsure or expresses doubt;

So, you can use doubtful in both contexts. If you wish to be most precise, finding a synonym is easy:

His experiments are questionable (ambiguous, problematic);
  His experiments are not convincing;
  I'm skeptical about his experiments;
Answer: I would say "I am doubtful of his experiments." which has the opposite meaning of "I am confident in his experiments."
Answer: It seems ok to me. But I'd use

I'm doubtful about his experiments.

And you could also use other words like questionable or unreliable:

His experiments are questionable / unreliable.
Comment: Somehow I don't believe *doubtful* and *unreliable* can be used in the same vein here. An experiment can be doubtful but still reliable at the same time.
Comment: Or the experiments have *dubious* results, or even *suspect* results.
Answer: You might want to consider the word dubious for expressing your sentiments:

His experiments are dubious.

According to Macmillan, the word means:

dubious (adj.) not sure about the truth or quality of something: I'm dubious about his ability to do the job.

and Collins:

dubious (adj.)

marked by or causing doubt ⇒ a dubious reply

of doubtful quality; untrustworthy ⇒ a dubious reputation

Indeed, the word is sometimes used to describe experiments:

In a dubious experiment, Leary had given psilocybin to hardened inmates in a state prison1

An incomplete or less than certain theory becomes a "model"; a dubious experiment becomes a "simulation", and so on.2

Remember, "A dubious experiment can only beget a dubious result." (Glaucon)

 F O O T N O T E S
1W.J. Rorabaugh, Kennedy and the Promise of the Sixties, 2002.
2L. Magnani & N.J. Nersessian, Model-Based Reasoning: Science, Technology, Values, 2002.
Comment: +1 I read this Q while at work and was gonna add *dubious* when I got home. But you've done it already. :-)
Answer: Technically speaking, you could probably justify referring to doubtful experiments where you mean you have doubts about any conclusions drawn from those experiments (for whatever reason). But it doesn't sound very natural to me, and I think it's probably not a good idea.
Ordinarily, people are "doubtful" when they are "full of doubts". By extension, we often say some specific statement of fact is "doubtful", meaning we doubt (don't believe) that it's true. You might stretch that a little further and say that someone's argument is "doubtful", to mean the line of reasoning is flawed - but most people would simply assume you meant you doubted the conclusion was true, so it's not a very meaningful distinction.
When it comes to experiments, that distinction between the investigative process and the final conclusion suddenly becomes much more important. I haven't looked into the matter too closely, but I note that on this Wikipedia page it says "Contemporary knowledge concerning the manner in which the human body reacts to freezing is based almost exclusively on ... Nazi experiments".
What those Nazi "doctors" did is an extreme instance of what people normally mean when they refer to doubtful or dubious experiments. It's not that we question the truth of whatever the dubious experiment demonstrates - it's the morality of performing the experiment at all that we have "doubts" about.
I would advise OP to say he thinks the scientist's experiment is flawed, inconclusive, questionable, poorly designed, inadequately documented, or whatever other specific shortcoming he finds. An experiment itself isn't something that can be true or untrue, but it can certainly be [of] doubtful [morality], and that's what I think many if not most people would understand if you described it using the word.
Comment: +1 Yes, there is a difference between dubious results and dubious experiments.
Answer: Are you doubtful of his experiments, or just about results?
To be doubtful of the experiments suggests that you think his methods, or perhaps his presuppositions are faulty.
If you are doubtful only of the results, or the significance of the results, that's quite a separate matter.
For this reason, I would avoid saying "I am doubtful of his experiments" because it is ambiguous, and leaves the reader/listener wondering what you really doubt.  Be more explicit.

I am doubtful of his conclusions.
I am doubtful of the methods used in his experiments.