Mechanism for Higgs Boson

Question: This is my first comment. I am not a physicist or mathematician, but I am interested in finding out more. I've recently read that the Higgs Boson gives itself mass, this is probably a painful over simplification to experts in the field but it's what I can get my head around thus far. I am trying to understand the mechanism behind this self interaction. What triggered the first instance of that interaction in the Higgs field? Again, I'm not sure if I'm evening asking the right question and need a gentle steer.
Answer: Indeed Higgs mechanism is, at first,  hard to understand, even for people with baggage in physics. I will try my best to make it understandable.
Our current theory of the universe at subatomic scales goes trhough Quantum Field Theory (QFT). With this model the universe is though as filled with differents field: one field for electrons, one for up-quarks, and so on. Every particle is an excitation of its corresponding field.
The Standard Model of Particles predicted that some particles, like the bosons carrying the weak interaction should have zero-mass, however they are incredibly heavy. Peter Higgs, in analogy of an effect descirbed in condesed matter, proposed that together with quarks, leptons and carriers of force, must exist another field (the Higgs field) that provides mass to those bosons via interactions with those. A helpfull analogy: consider the mass as the effort you need to move an object. Moving it through vacumm requires no effort, so it has no mass. However if the space is filled with water (representing the Higgs field) the object will be much mor complicated to move and, hence, more massive.
A straightforward generalisation of this effect is that the Higgs boson couples no only with weak bosons, but will all the particles. So all the (fundamental) have a mass proportional to the stregth of the coupling with the Higgs field.
While doing the maths, one see that the simples field we can accept is a scalar field with no electrical charge. Once one calculate the dinamycs of the field, there are three terms that arises in the equations:
 - A term proportional to $H^2$ which gives the mass of the field
 - A term proportional to $H^3$ and a term proportional to $H^4$ which gives interactions between the Higgs field with itself.
All of those can be seen as interactions between Higgs particles

The main problem with this representation is that lead to the confusion thet interactions between fields, go linearly in time, i.e. that in order to obtain mass, a particle must interact with the Higgs field first. However in Quantum Field Theory, the concept of time is always dificult to understand. QFT is a covariant theory: must give the same results independently of the observer. Since two observers can have different notions of time, (see Relativity of simultaneity for example) the notion of "before" an "after" is not always clear.
The image one should take in mind while studying particle interactions is that all the interactions happen at the same time. The Higgs field does not need to interact with the Higgs boson to aquire mass, but because it is always interacting with itself, it shows mass. Nothing "trigger" a first interaction which lead to the dynamics of the field.
(Note: In a poetical sense, maybe this first evet could have be considered the Big Bang, which, in the big picture is the origin of every interaction. However probably is not the answer you are looking for and the Standard Model is not sure to be applicable in the first instants of the universe.)
Comment: Hi Alejandro, I did try to read around the Higgs mechanism before posting, but could not even begin to understand it. I needed somewhere to start. Your answer was very helpful, thank you.
Comment: I am just thinking aloud here: could quantum computing ultimately harness the Higgs boson interactions to artificially provide mass (energy) to particles in order to manipulate them?
Comment: Sincerly information theory and quantum computing is  far from my area of expertise. Maybe you have another excelent question to ask to Physics SE
Answer: The Higgs Mechanism
Until 2012, people actually laughed at Peter Higgs' idea of energy creating matter on a whole different plate than the rest of physics. But on July 4, 2012, the CERN LHC discovered evidence of the Higgs Boson, the exchange particle in the ordeal and Higgs was awarded the Nobel Prize. This proves that in physics, an insane idea that makes utterly no sense and that the rest of the population denounces can be the most brilliant theory ever discovered (another example of this is Relativity).
Scene: The Big Bang goes off, just pure energy, no fermions. In less than a sextillionth of a second, the elementary particles are formed and the universe becomes a super dense fog, trapping all of the photons for the
300,000 years. The formation of these particles is key. As explained under Energy-Mass, most of the energy in baryons actually comes from the energy in the gluons. The quarks themselves account for less than 1% of the total mass. This is called intrinsic mass and it too comes from energy. This property originates in the depths of quantum field theory, a phenomenon in which everything belongs to its coordinated field, the gluon in the gluon field, the photon in the photon field, the quark in the quark field and so on. These fields are kind of like maps. Take the photon field for example. Imagine that everything in the universe has a certain photonic quality. In absolute darkness, this is usually pretty close to 0. There was a problem here. When you add energy to a field, it vibrates. That vibration creates the photon. Everything, gluons, quarks, electrons, is just an energetic vibration on its field. There's more, these field vibrations all interact with one another by exchanging energy.
    1950s Quantum Field Theory gives an accurate description of electrons, but it explains that it has no mass and thereby would not experience time. However, we know for a fact that electrons add weight to atoms and experience time. You see, the electron, like most leptons, has a two-way spin, switching at a steady pace between "left-handed" and "right-handed." Since it does this chronologically, it has to experience time. This is where the Higgs mechanism becomes involved. The universe does not like you if you're left handed. Now I realize I'm insulting 10% of the global population, but it's true, the universe cares so much that to be left handed you have to possess a certain particle.
    Before I go any further, let's take a look at gravitons. They are definitely massless and do not experience time, they never stop and move straight through atoms, not once switching "hands." Meanwhile, the electron is constantly being blocked, by nuclei, electrons, or any random fermion that happens to be in their way. Why do the graviton and electron behave so differently if they're both vibrations in their quantum fields? There has to be a property that blocks the electron that doesn't apply to gravitons or photons.
    This is where the spin comes in. The certain particle that allows electrons to switch "hands" is called weak hypercharge. While non-ambidextrous particles can fly through space without any form of impediment, the weak hypercharge forces "left-handed" electrons to interact with the weak force along with the electromagnetic force which happens to be the makeup of the electroweak force. Coincidence? I think not. Anyway, to switch between these forces electrons have to be able to shake or find a weak hypercharge (depending on their spin). So where can I find a weak hypercharge? On the Higgs field.
    Unlike the other fields which, in empty space, stay around 0, the Higgs field has a positive charge, attracting electrons. Another thing that makes the Higgs field stick out is its everything-ness. While other fields only have one of their particle per energetic vibration, the Higgs field has an infinite number of weak hypercharges everywhere. As the electron passes through space, it is attacked by weak hypercharges, trying
to attract or break away from the electron causing it switch "hands." The more energy on the Higgs field, the faster the weak hypercharges sink and break away. Thus, the electron cannot get through the Higgs field and is forced to feel mass and therefore live for an infinite amount time.
    Though due to gluons and their natural attraction to one another, quarks would not be capable of moving the speed of light anyway, they too experience the mark of the Higgs field. Quarks do not need weak hypercharge, but that is actually just a side effect of the Higgs field, the real purpose is to provide a slower/stopper for particles like electrons, that should be moving the speed of light. The real question here is not "what does" but "what doesn't." There are two particles that do not (in rest) interact with the Higgs field. They are the graviton and the photon.
    Gravitons do not interact with anything in the first place. They simply travel through space carrying gravitational waves. There is an extremely dense mathematical explanation for this, but physics is supposed to be fun, right? Photons, on the other hand, do interact with matter, but not other fields. Unlike most particles, photons only give energy to other photons, therefore they do not interact with the Higgs field. Again, a dense mathematical explanation - for your professor to explain.
    But what carries the Higgs field and its collection of weak hypercharge anyway? Enter: Higgs Boson. Like for other fields, the Higgs boson (AKA God particle) is created by the energetic vibration of the Higgs field. It is literally the exchange particle of mass. The Higgs is also probably the most expensive particle. It took over $13 billion to find this particle at the LHC, but when it was done, the standard model was finished (at least for matter). Though the Higgs boson has a mere half-life of 10-22 seconds, it proves critical to all of physics.

Mechanism for Higgs Boson


Where can I get access to GPU cluster for educational purpose?

Question: I want to work on NVIDIA GPU cluster for my thesis.  But the cost of clusters are too high for me to bear. Although I can buy a couple of latest GPU cards, but buying cluster is impossible for me at least right now.  What is the alternative? Are there any Non profit organization promoting and renting clusters for educational purpose at subsidized pay per use rate?
Comment: Where do you work ? Country and institution ?  There's no point anyone providing, say, information applicable only in PRC to someone in USA.
Comment: For general purpose supercomputing, it's usually possible to apply for accounts on various machines and get small allocations to start (say, 10,000 processor-hours). The general idea is to use those hours to get familiar with the machine, generate some results, and then take those results and write a proposal to get a larger allocation there, or on another supercomputer. Presumably, a similar process might exist for GPU clusters. You also might be able to ask around at your university and see if someone in your professional network would be willing to give you an account on their machine.
Comment: @GeoffOxberry Can you provide links to where I can apply for an account with a small allocation for general purpose supercomputing? Thanks.
Answer: If you work at an institution in the US or have collaborators at one, you should look into the XSEDE program. This is a federation of the National Science Foundation funded supercomputing centers in the US which provides compute cycles on a variety of large-scale machines to open science research in the US. There are a couple of machines with GPU resources including Keeneland and Stampede.
Startup allocations are readily available to academic researchers and can be applied for on the XSEDE User Portal. As a student researcher, you will need to work with your academic/thesis advisor to get them to apply for time. If your application for an allocation of time is successful, the time itself is free.
Answer: A final alternative is to rent (or apply for time on) a GPU cluster from Amazon EC2.  As Bill and others have mentioned, most countries provide some national or regional high performance computing resources for free to their scientists.  If you don't have one in your area, it is mostly a matter of finding a collaborator who does.


Honda Civic braking problems in warm climate

Question: I have a 1991 Honda Civic wagon that loses braking power on hot days. I have it working for the initial press, but as I hold down the brakes I slowly lose braking. I have to repeatedly press at red lights, and after a long day of driving my leg gets tired (ha-ha). Still on a cool day the brakes work without problems. A friend of mine said it might be the brake master cylinder, but I wanted to make sure.
Comment: You've changed a line without bleeding the brakes, that doesn't sound good.
Comment: Have you bleed the brake recently? Did your master cylinder ever been replaced? I had a soft brake line that was bulging when braking and was even worst during summer.
Comment: I've never bled my brake, and never changed the master cylinder. I did change brake line a year ago (left rear side) but this problem has been around long since I've own the car.
Comment: You're probably right, but what happened was the line broke and I didn't have a lot of experience working with brakes. So I replaced it and just filled it backup. Worked like it did before, same problems and all.
Answer: I had brakes issues with my 1987 Toyota Land Cruiser since 2 years, I've had the same symptoms has you.
Since then I've change all brakes (rear/front), replace some flexible brake hose that were soften due to age and anti-rust treatment with stainless steel hose(might be overkill). Then I bled all four brakes to remove air in the lines which give me a firmer pedal.
Now I have brake but I have to depress my pedal way down to start braking. I know that my master cylinder is faulty because I had bleed it in place and my pedal got less travel to get the same result.
So, to answer your issue:

Check any flexible lines to make sure they are in shape: no cracking or bulging under pressure. Replace if necessary.
Inspect brake bad and drums, replace if necessary
Then bleed the brake, it's cheap (only need new fluid) and fast to do. You should now have firmer brake, if not;
You could bleed you master in place to see if it make anything or replace it.

Replacing any component of the braking system you'll need to bleed the system according to the manufacturer specifications.
Comment: Thanks for all the help, I'll be sure to try all that. Lucky for me I bought all the books for my car so this should be easy to start.
Comment: @fassetar, while this is a good answer, and probably a correct one (air in the brake system would indeed cause same symptoms), you should not award the acceptance just because it "looks" right. Try to fix the car first, and if that is indeed what had caused it, then accept.
Comment: Check under the brake pedal on the floor for any leaking brake fluid.  When the master cylinders fail it usually will start dripping some fluid inside the car there.
Answer: If after bleeding the brakes and checking the mastercylinder check the replaced brake line. Did you install it in the exact same position as the original? If it passes to close to an exhaust component the heat from the exhaust may be boiling the brakefluid. The boiling fluid would contain a bubble of air that is compressible resulting in low pedal pressure but only while the engine and the exhaust is warm.
Comment: I did install it correctly, but that does add a possibility. I know the left side is fine but the rear right side it could be possible. Sometime when I break the car does slightly pull left more than right. Thanks for the information!


Disable TSA lock allowed?

Question: I will be traveling from the Netherlands to Poland. I have a seperate TSA lock, but it is well known that those have a vulnerability because one can get easily hold of the TSA master key. I want to disable the TSA keyhole by, for instance, glueing it. I don't expect the TSA lock will be used, so can I get in trouble for this?
Comment: Other than any **thief** may become angry (and it is otherwise locked) , no. If any security needs to open the bag and it is unlocked should also pose no problem. No idea what happens when security needs to open a locked piece of luggage.
Answer:
I want to disable the TSA keyhole by, for instance, glueing it. I don't expect the TSA lock will be used, so can I get in trouble for this?

No. If security needs to open it when you're not present (this is very rare) then it's the same as any other luggage without a TSA lock.
If you are present then they'll just ask you to open it. If you're at customs somewhere and you cannot open it (again, similar to a non-TSA bag you cannot open) then they'll have tools to do so (i.e. forcing some part of the luggage, likely rendering it unusable) or they can confiscate the luggage.
Comment: Many people do not bother to lock their luggage, just close it such that it can not fall open.
Comment: @Willeke yea, they'll probably try that first if they need to break into it. I don't think they often do that for no reason though, so as long as there's nothing special about it (or the passenger associated with it) they'll just leave it alone.
Answer: Do not glue it. Use an other lock. [This is just for infra-european flights]
For all inspections, you are required to be present (also for security: if it contains a bomb, you will get it). [But this is also a disadvantage, if they fail to find you, e.g. in an airport with non-speaker notification), you will be denied to board, if the baggage cannot be checked and loaded on time.
For the few cases they will not require you, they will have no problem to open your case (and possibly it is the least of your problems) (braking the lock, the luggage).
But do not carry valuable in your baggage. A good lock will tell staff that you have valuable stuff in it.
Personally I never used a lock, and I never got anything stolen (very many countries and continents, some not really safe, or well know to be used to corruption, also on customs).

Disable TSA lock allowed?


Windows 2008 - Finding out restriction on user accounts

Question: I don't know why but my findings tells me that running my process as "SYSTEM' (LocalSystem),
can connect me to another server. Other users are completely stopped from doing so.
Is there a way for me to find out what restriction imposed on other users?
Thank you
Comment: is that localservice or system?
Answer: kepung,
The LocalSystem account doesn't have access to other servers, as indicated by the name.  If you can offer up a bit more information, we might be able to assist if this is still an issue, but as it stand now your question is a bit sparse.


How does 2,3 biphosphoglycerate works to release oxygen bound to the hemoglobin?

Question: I read on Wikipedia that 2,3 BPG binds with the deoxygenated state of hemoglobin and helps in stabilizing it. It was also written that it helps release remaining oxygen from the hemoglobin. How?
https://en.m.wikipedia.org/wiki/2,3-Bisphosphoglyceric_acid
Comment: Possible duplicate of [Effect of 2,3-bisphophoglycerate (2,3-BPG) on haemoglobin](https://biology.stackexchange.com/questions/55683/effect-of-2-3-bisphophoglycerate-2-3-bpg-on-haemoglobin)
Answer: You've answered your own question. The association/dissociation of oxygen is an equilibrium reaction. If you stabilize one state, you move the equilibrium to that state. 2,3-BPG helps release oxygen from Hb exactly by binding and stabilizing deoxy-Hb.
Answer: From more mechanistic point of view, 2,3-biphosphoglycerate contains 2 negatively charged phosphate groups, which interacts with positively charged groups of each beta-chain within deoxyhaemoglobin decreasing the oxygen affinity (see good old Stryer Biochemistry)
Answer: If I understand your question, you want to know, HOW the 2,3-biphosphoglycerate helps release the oxygen from the heme. In addition to other factors like the blood temperature, the pH, and the ambient pCO2, it modifies the heme oxygen affinity. It binds, using salt bridges to lysine and histidine of deoxygenated heme subunits and, by this, changes the deoxygenated heme's conformation. The so modified heme conformation renders the (oxygenated) heme-oxygen bond instable. The altered heme subunit conformation cannot hold the oxygen atom anymore, which dissociates from the heme subunit and diffuses to the mitochondria, thus allowing for ATP production. This process is called "the hemoglobin oxygen affinity is being reduced" and one of the promoting factors of this process is 2,3-DPG.
Comment: This looks like an informative answer, but it would be made more helpful for others if it cited sources or linked materials.
Comment: Comment to M.P.'s note from Aug 25, at 22h14
Comment: Comment to M.P.'s note from Aug 25, at 22h14. From my point of view, the 2,3-DPG does not stabilize the hemoglobin but the oxygen's affinity to hemoglobin, as is stated in the original Q and also in the first A to the original Q, This is far from being the same thing. My intention was to draw attention to this fact, which was incorrectly stated in the original Q and also in De Novo's upvoted answer. The source of my A (answer) is : https://en.m.wikipedia.org/wiki/2,3-Bisphosphoglyceric_acid
Comment: It's helpful to have these sources in the answer. I don't take a position on the subtleties of deoxy Hb stabilization mechanism, but if these subtleties exist, it's handy to have very clear visuals or explanatory references, e.g. slides 15-20 or so of [this presentation](https://www.umassmed.edu/globalassets/office-of-undergraduate-medical-education-media/documents/protein_structure_notes_2016.pdf). Wiki is also generally fine, your page looks reasonable, though I don't see any notable distinction between the answers. The important thing is to have all this stuff in the answer itself.


building a flagstone patio near fence with electric and telephone line

Question: We are trying to build a small patio along the end of our yard (along the fence), but there is a small power line that runs through all the houses in our side. Is it safe to build a patio along the fence which is closer to the power line? (the power line is in our neighbor's yard)
Answer: In many places in north America you have call and get a utility chosen contractor to come out and mark where there lines are.
This is usually a no charge service and covers you in the event you hit something unexpected
Answer: It's safe.  The power company is very careful that no one gets hurt.
What you need to be concerned about are utility easements.
Check with the power company especially if you want to plant a tree.
They need to be able to get in and trim trees and you are not allowed to let your project get in the way of trimming the trees.
Other than that, you are safe.  I'm an electrical engineer and have had issues with the power company and access to the trees they needed to trim.


Manage Content Types in Site Pages library

Question: Is it possible to manage content types for the Site Pages library in the browser? If this is not possible, what's the rationale that this can be done in nearly every library and list, but not Site Pages?
Answer: No, it is not possible. The OnLoad event of the Advanced Settings page hides the Content Types section with the following code:
<code>this.ContentTypeSection.Visible = this.List.AllowContentTypes
    && this.List.BaseTemplate != SPListTemplateType.UserInformation
    && this.List.BaseTemplate != SPListTemplateType.WebPageLibrary;
</code>
I do not know the reason why it is protected, but it is definitely explicitly singled out along with the User Information list. That said, you might be able to set ContentTypesEnabled using code. But you will likely be in unsupported territory if you do so. If possible, you may want to consider using Publishing Pages, as those support multiple content types.
Answer: I think they want you to use the Enteprise Wiki functionality if you want Content Types and Wiki pages. The Enterprise Wiki functionality uses the Publishing Pages library (unlike ordinary Wiki pages that use the Site Pages library) and the Pages library has Content Type management enabled for the whole Page Layout Publishing architecture to work.
Answer: This is a very old post, but I have found that if you open the Site Pages library in SharePoint Designer, you can enable management of content types from there.
Comment: The downside to answering old questions here, is that the question was likely specific to whatever version of SharePoint the OP was using at the time.  Newer versions (not sure where the cutoff was) actually Do allow content type management in SitePages directly in the browser. Unfortunately, the OP didn't tag this with which version they were using, but since it was posted in 2011, it couldn't possibly be any version newer than SharePoint 2010 -- did you validate that your answer works in older versions?


How could the SNES take advantage of in-cartridge coprocessors that weren't invented when the SNES came out?

Question: The SNES had a number of "enhancement chips" that were available in the cartridges. These chips did lots of different things. How did these chips actually transfer data to the SNES? How did the SNES use chips that weren't available at the time of its release?
Comment: But if the chips actually used the SNES and not the other way around, there would be no problem? :)
Comment: They connect to the CPU's main bus, so just reading and writing to the right address is enough. They don't change the CPU's instruction set or anything. Of course this also means you are limited by the address space and the latency and throughput of the bus.
Comment: Are you surprised when a modern computer interfaces with a peripheral that wasn't invented when the computer's own hardware came out?
Comment: I think you are.missing that these consoles did not have an operating system or firmware. Everything was in the cartridge, so the ROM code could address any hardware on the bus, whether it was part of the console or inside the cartridge.
Answer: The cartridge connector for the NES, SNES, and other consoles of that era directly exposed the main CPU's address and data busses to the cartridge, complete with the control signals you need to know what accesses the CPU is doing (reads, writes).
This allows cartridges to attach "enhancement chips" directly to the CPU as-if those chips were part of the SNES itself, in exactly the same way as the PPUs and SPC700 (S-SMP for audio) were connected to the CPU. A cartridge designer would know what hardware is in the base SNES (because that's fixed by Nintendo), and could arrange for their enhancement chips to appear in the main CPU address space as another co-processor, just as Nintendo arranged for the PPUs (for video output) and the SPC700 (for audio) to appear in the main address space.
Then, code running on the main CPU from the ROM in the cartridge would know where in the CPU's address space a given enhancement chip (in the same cartridge as the ROM) would appear, and can drive it by writing to the right parts of address space to send data to the enhancement chip, or by reading from the right locations to get results back for the CPU to make use of or transfer to another chip.
It doesn't matter that the chips were designed after the SNES was on sale - the cartridge designer is responsible for ensuring that the chips do the right thing from the CPU's point of view - and thus the enhancement chips were often designed around what the SNES expected.
Comment: The modern-day analogy is someone creating a GPU with an onboard SSD drive along with necessary drivers to do the I/O operations and give you a game with the GPU. This is, of course, very expensive and this is one of the reasons why cartridge games are no longer popular, and the main reason why PS1 took off like it did.
Comment: The SNES cartridge connector has a core set of 46 pins that most game cartridges used. There's an additional 16 pins (arranged as 8 either side of the main connector) that are used when there's an enhancement chip in the cartridge, carrying an additional address bus, audio input lines, etc. You could tell if a cartridge had an enhancement chip inside by looking at its edge connector.
Comment: @Nelson I remember when the PS1 and the N64 consoles had both been released.  The main debate among me and my friends at the time wasn't about the cost.  It was how long we had to wait for the loading screens vs graphics quality.  The PS1 seemed to take a long time to load stuff and the N64 was blazing fast.  But the same games on N64 often had lower quality graphics (presumably because even the largest cartridges held 1/10th the data vs. a CD).
Comment: @user4574 Yet the home console market is now all disc-based games. Technically you can now go back to using SD drives, but for something that they want to sell 10s of millions, a production cost factor of 10x is a HUGE amount of money. Strictly speaking SD cards have way more capacity than Blu-Ray for a while, but the cost hasn't gone down enough to justify it.
Comment: @Nelson "Yet the home console market is now all disc-based games".  That's mostly true.  The major consoles like Xbox and Play Station do have an option to use discs.  The Nintendo Switch on the other hand (which is used as a home console via the dock) still lets users plug in cartridges if they want to go that route.  And all three of those consoles have network connectivity and online stores that allow completely bypassing any physical media (direct download to internal memory).
Comment: @user4574 That's because we pay for our own media AND bandwidth. Their cost was reduced even further. The media consistency is a nightmare. I've had games that would sometimes crash just because the media wasn't the right "speed", and this was on the DS.
Comment: @Nelson Good analogy. I think it can be taken a step further to say that the GPU can only be used for that game.  The next game you buy will have to have its own GPU.
Answer:
How did these chips actually transfer data to the SNES?

The cartridge connector is a bus interface. Much like ISA-Slots in a PC, it contains everything necessary to access memory or memory mapped devices.

How did the SNES use chips that weren't available at the time of its release?

Ever wondered how a PC can take advantage of a interface card that was not developed when the PC came out? Like a VGA card? Just by plugging it in, even before any DOS or extra drivers are loaded?
Because it brings basic drivers in an extension ROM. Plus drivers loaded by DOS and/or Windows.
It works the very same ways on a console. After all, the cartridge does not only brings some 'co-processor' but also a ROM with the game containing all code.


How to increase filename size limit on EXT3 (on ubuntu)

Question: The default limit of how long a filename can be on EXT3 is 255 characters. I have a unique requirement where I need much longer filenames (apparently because mod_rewrite of apache uses filenames for storing). Is there any setting I can tweak to increase this limit from 255 characters? (Or if I can change mod_rewrite setting not to use files)
Comment: What kind of rules you have that require it? Used mod_rewrite quite a lot, and never had this kind of problems.
Comment: Actually, we have a htaccess definition which rewrites the URL. One particular URL (not including the query parameter part) is more than 255 characters long and htaccess is not triggering in that case. Try it.
Comment: I would suggest to rethink/rewrite the mod_rewrite/htaccess logic. There is no sensible reason to need 256+ character filenames. Also - if you are rewriting url to another url (and not to filename) - filesystem limits are not related.
Comment: This is related to http://serverfault.com/questions/140852/rewritten-urls-with-parameter-length-255-dont-work -- can you help?
Answer: This is a fixed limit in ext2/3/4, so unless you can change filesystem or the length requirement you are stuck.
Reiser is the only common filesystem that springs to mind as supporting longer filenames than that (I know someone who chose it over ext2/3 for that reason, though I forget why he needed to support very long filenames).
The length limit is per name, so you can have paths longer than 255 characters as long as individual names along the path are not over-sized. This maybe enough to deal with the situation if you can update your rules to output paths of the form "/store/200-character-dir-name/200-character-dir-name/200-character-file-name" rather than "/store/600-character-file-name". Though requiring very long names with or without splitting it into paths for shorter names seems odd enough to imply there might be an overall design problem to be addressed (I say might as there could be good reason for the requirement!).
Be aware that even if you change filesystem or use the path approach to split the long names, some tools may not like the long names/paths (some archive/compression file formats won't support either, for example).
Comment: On Linux PATH_MAX is 4096. It might be possible to get around that for some syscalls by changing cwd and using relative paths, though. That being said, a redesign to not need such long file names in the first place is perhaps the least painful approach.
Comment: Yes, redesign seems to be the way to go. Although sometimes customers won't listen that there is nothing we can do to circumvent 255 charatcer approach.


What is Natsu's Birthday?

Question: I did some digging and found that Natsu, or atleast the Natsu we know, is around 20 years old but I want to know his birthday which I can not yet find an answer for.
Comment: It is revealed in the series that he is a lot older then that but just doesn't know t
Answer: I believe that Natsu is a year older than Lucy. The year they came from was 377 to be exact, if you then add the year 777 it's exactly four hundred years so Natsu would have been 11 years old as Lucy was 10.
So if Lucy was born 767 that means Natsu was born 366, as to the exact day it's unknown but because his parents named him "Natsu" (summer), as the first day of summer is around the middle of June and not July we could say Natsu's birthday is June 20th 366.
http://fairytail.wikia.com/wiki/Lucy_Heartfilia
↑ Fairy Tail Manga: Chapter 465, Pages 11-13
↑ Fairy Tail Manga: Chapter 468, Pages 2-14
↑ Fairy Tail Manga: Chapter 468, Pages 14-18
↑ Fairy Tail Manga: Chapter 400, Pages 15-19
↑ Fairy Tail Manga: Chapter 414, Pages 8-17
Comment: Welcome to [anime.se], a Q&A site about anime & manga. This might be a starting point for a good answer, but could you provide some sources/references to back this answer up? Meanwhile, consider taking a quick [tour] to understand more how this site works.
Answer: The Author hasn't provided an official birthday yet. All we know is that he was born some time in the X300 century.
Answer: His birthday is July 7th concluding to Hiro Mashima. The year has not been specifically been said yet, but it is some time in when dragons disappeared. Since Natsu was trained by Igneel, he must have been born before this date, presumably several years before to allow time for training and such. So around X777.

What is Natsu's Birthday?


Not Able To Duck in Counter Strike Condition Zero

Question: Recently I started to play online on various server, one of them downloaded some maps, sound etc and also created direct link to server at gateway of Counter Strike Condition Zero.
Everything was fine that time but when I restarted the game and played my duck key was stopped responding.
To get rid of the problem I restored my key to default and set again, choosing different key for duck but no luck, even  but the problem remain each time I played the game.
One more thing that the direct link to server which was created when i connected to online server didn't disappeared even after uninstalling and reinstalling the game, I dont know how this happen but I have deleted all the file clear registry.
Answer: Create a file called autoexec.cfg in your Steam/steamapps/common/Counter-Strike: Condition Zero/cscz/cfg.
I haven't double checked the folder names, so you'll have to correct me on that one.
Edit the file and add the following:
<code>bind ctrl +duck
</code>
This file will be executed everytime the game starts, and thus binding your duck key to the control key every time.
Comment: Uh. The duck key is the one not working here.
Comment: My bad, i'm tired. Fixed.
Answer:
Go to CsCz directory- local disk "C" > Program Files > Counter Strike Condition Zero > czero.
Locate File userconfig.cfg.
Open it with notepad.
Delete whatever written inside it.
write- bind "CTRL" "+duck"
Save file and exit. Rum cscz.
You are done. It worked for me.
Hope You have solved your problem.


Migrating data from ArcSDE to SQL Server Spatial Database

Question: I am looking for a process or a tool that would allow me to migrate data from an ESRI SDE Database to a SQL Spatial Database. This would include converting the ESRI geometry to SQL geometry types, as well as potentially having to convert ESRI domains to lookup tables. I have seen some tools out there that will take shapefiles and convert them to SQL spatial format and I have been successful in doing that but given the amount of data and how dynamic it has been, I would prefer to not have to convert my entire database into shapefiles first. Would it be easier to go from a File/Personal geodatabase?
Comment: Do **NOT** pass a perfectly good spatial database through shapefiles as an exchange format.  FileGDB can handle the twists and turns (as can ASCII), or just go with DB-to-DB load.
Answer: If you have ArcGIS now, you should use the FME Workbench found in the Data Interoperability Extension to 'read' your SDE data and 'write' it as SQL Server Spatial. Or, get a trial version and migrate all your data over before the trial runs out.
In terms of the domains, If there is an opposite of 'table to domain', use that, and again use FME to load the table as SQL Server non-spatial data.
From there we use Python with pypyodbc to move data between MSSQL servers.
We use QGIS as our main SQL Server Spatial Editor.
Comment: Thanks for this. We will probably have to get a trial version of the Data Interoperability extension. Do you know if that comes with an Advanced License? I am not seeing it in the list of extensions in Arcmap. Do you have any familiarity with the Migrate Storage tool in regards to an issue like this? Thank you again
Comment: Data Interoperability should be available with Advanced license - check your my.esri.com portal for a) the option when provisioning a license to include the data interop. extension and b) that it is available in your list of downloads from the ArcGIS Desktop installation files. Also: the migrate storage tool looks like a way to move your SDE data from the 'old' spatial data format that SDE used to use to the 'native' spatial data format now employed by MSSQL, Oracle, and PostgreSQL (postgis geometry)...but not to convert your data to a 'native spatial database' that doesn't use ArcSDE
Answer: Why not use GDAL/OGR? You should be able to convert directly from your sde database to sql server. Here are some links that might help:
This one should give you the syntax for your sql server connection:
https://alastaira.wordpress.com/ogr2ogr-patterns-for-sql-server/
This helps with the syntax for your sde connection:
How to migrate data from ArcSDE to PostGIS?
Comment: I've never been able to get GDAL/OGR to connect to/from our MSSQL instances...


Is an IDP required to drive on an American license in Bangladesh?

Question: If one has an American license, is that sufficient to be able to legally drive in Bangladesh ?
I read this about Australia https://travel.stackexchange.com/a/5806/4584 but found nothing for Bangladesh. And this post https://travel.stackexchange.com/a/451/4584 made me ask my question
Comment: Besides legality, if you are not used to drive in any developing country (& China), just don't think about it. You will definitely run into big mess.
Answer: Your post is pretty apt. I have driven all around Asia without a license actually.
But, the good thing is Bangladesh accepts International Driving Permit.
So, that's what you should apply for (to drive there).
Comment: @happybuddha where did you read that "An IDP is a license translated from a native language to English."? It's translated in many different languages actually. As shocking as it may sounds to you, English isn't spoken everywhere.
Comment: So...you're saying the OP **should** get an IDP?
Comment: yes! Answer edited.
Comment: -1. Your "This post" is the same as I posed in my question ! (And this post ..made me..). So, to me, it isn't apt. I will not engage in illegal/corrupt practices. An IDP is a license translated from a native language to English. Mine is in English. So, I circle back to my original question :If one has an American license, is that sufficient to be able to legally drive in Bangladesh ?
Comment: I was actually referring to your post. It wasn't so obvious after the edits done to my answer. You are wrong about IDP. It isn't a mere translation of your license, it is a permit. I have updated my answer with the Wiki Link to IDP, so you can learn a bit more about it.
Comment: I looked up the wiki and the image in there says Bangladesh dont honor the 1949 convention (IDP). And the AAA page (http://www.aaa.com/vacation/idpapplc.html) says IDP is indeed valid in B'desh. Guess I will never know till I get pulled over in B'desh :(


What is allele-specific gene expression?

Question: I read somewhere that the two different alleles which we (and other species) inherit from our parents are not expressed equally in our cells. Which genes show allele-specific expression? How and why?
Answer: There are a few well known examples of allelic exclusion (which is what you've described):
In females (human and probably other mammals too) one of the two X-chromosomes is silenced (shut down) during embryo development. This means that some cells have one allele (from maternal X) active, while other cells have the other one (from paternal X) active. The actual mechanism behind this is quite complex, but ultimately results in the complete epigenetically-controlled prevention of gene expression from one X-chromosome. This is necessary because otherwise females would produce twice the amount of all proteins on the X-chromosome compared to males.
Another well known example relates to the genes that lead to the building of the B-cell receptors and antibodies. During maturation of the B-cells different segments of these genes are rearranged in a process call VDJ recombination. In order to make sure that the cells produce only one kind of B-cell receptor/antibody one of the two alleles for these genes is silenced after a certain rearrangement step has taken place.


How do you prioritise certain user journeys in a responsive website?

Question: Working on a responsive website where we have decided to make all content available on mobile but prioritise journeys we have identified as being key. What ways can I prioritise these journeys is it that I put those in the main navigation then possibly have a 'more' button that expands the menu to show the rest of the site? What is a good way of doing this?
Answer: It really depends on the goals of the site. In general, user journeys may be different, but the funnel should lead to as few outputs as possible. Most of my projects are marketing ones and in these cases the highest priority is to lead the user to purchasing the product. However, even this can be achieved in several ways. E.g. you have an audio system we want the user to buy. You should construct the funnels so that the user journeys lead to for example:

purchasing the product in an online store (output: online store, price comparison service)
visiting a dealer to see product features (output: dealer list, contact details)
educating the user to know more about the product, to trigger the ROPO (research online, purchase offline) effect
triggerring seeding the information by the user in social networks
contacting/asking a question via a form
etc.

Now, as the main goal for the website (from client's perspective) is to increase sales, to prioritize them you will need statistical data. Which of the outputs have best performance regarding the sales? Once you have this data, you should facilitate and streamline the selected ones.
After that you can (and should) run tests on user journeys as well, to identify potential problems for users getting where you want them to get. There can be various obstacles, both functional ones, wording, graphics, etc. to eliminate.
Answer: Regardless of if the site is responsive or not it should be based upon two key things:

What the business aims are (e.g sell more widgets)
What the usersaims are (e.g. research about widgets to buy the right    one).

The scenarios for mobile and desktop users often are superficially different but the core needs and aines often remain the same.


Possible application of Polya's Urn on Portfolio's Investments?

Question: I wanted to find some more information of this topic, but I found very little.
I might be interested in optimizing a stock investment portfolio. Maybe I could use beta or some other common risk measure to weight each stock, when I apply it to real data. However, here is the theory part:
There is an urn containing balls of two colors, corresponding to the two investments.
The goal is to play so as to maximize your expected return.
We assume the division of the portfolio into two investments $(X_{n},1-X_{n})$.
At each time a ball is drawn and replaced, and the corresponding investment is monitored: the first is monitored with probability $X_{n}$ and the second one with probability $1-X_{n}$.
If the monitored investment rise above some threshold, then a portion $\gamma_{n}$ of the other investment is relocated into that investment.
Moreover,
If we define $T_{n}$ recursively by $\frac{T_{n}}{T_{n+1}} = 1-\gamma_{n}$, this is a time-dependent Polya urn process, with $a = T_{n+1} - T_{n}$, modified so that the reinforcement only occurs if the chosen investment exceeds the threshold. If $\gamma_{n}= \frac{1}{n}$ then $a_{n} \equiv 1$ and one obtains a diagonal Polya urn.
How should I proceed? Any suggestion about materials/paper to read about this topic? Applications?
Answer: As a Polya urn is often referred to as the rich get richer, it maybe possible to use his urn to get richer.
It is known that these urns can be related to the Dirichlet-multinomial distribution.  That being the case, i suggest looking at this link, http://jmlr.org/papers/volume18/10-231/10-231.pdf, to see if it will answer your question.  It too deals with time-dependent polya urns


Why does Fluorine have a high affinity for Calcium?

Question: I keep hearing from several websites and videos that Fluorine seems to like bonding to Calcium specifically; can someone please tell me why? I can't seem to find a clear response on the internet. Fluorine has a high affinity to Calcium, more than other elements. Why is that?
Answer: Actually it's not the question of affinity but insolubility of CaF2. As this salt has solubility product of ~4×10−11 which is mostly caused by nice packing and strong ionic interaction (see enter link description here)
Comment: The free energy of formation is also quite negative. Combined with the low solubility, it indicates that it will readily form and will not go in to solution, so once formed it is quite happy as is.


Working as data scientist for a nonprofit company

Question: Hello I work as data scientist for a private company.
I am interested in working for a nonprofit company, such as a research institute (public or private) or a company that takes care of  issues such as  environment, public health,  social improvements. Even an internet company like Wikipedia can be interesting.
Does anybody know if nonprofit companies hire data scientists?
Comment: I've flagged this to be closed as "unclear what you are asking", because the answer to your question as posed is obviously "yes". Of course they do. What are you really asking? Because if that **is** what you are really asking then I dread to think what questions you ask of your data as a data scientist...
Comment: Basically, you are asking if someone can find you a job.  That's spam.
Comment: Basically I asked a question that was clear  enough to somebody and I received two good answers. Of course anybody is free to think what their mind suggest them to think.
Answer: I see at least five ways to approach this problem of finding a data scientist position/work specifically at non-profit, non-governmental or similar organizations, as I describe below. I hope that this is helpful.

First, and the most obvious, way is to search major job portals, such as indeed.com, dice.com, monster.com, CareerBuilder, Glassdoor and others, for data scientist or similar positions, such as data analyst, data engineer, quantitative analyst, statistical modeler, or even market researcher.
The second and also obvious way is to tap your professional social networks and research or inquire your contacts for any potential data science work opportunities in the areas of your interests.
The third way is to search web sites, focused on the non-profit and related topics (they usually have a job listings or similar section) as well as specialized non-profit job portals. For example: http://encore.org, http://idealist.org, http://bridgespan.org, http://cgcareers.org, http://opportunityknocks.org, http://foundationcenter.org, http://thenonprofittimes.com, http://philanthropy.com, http://ynpn.org, http://philanthropyjournal.org, http://nonprofit-jobs.org, CoF Jobs (section isn't easy to find), http://careers.councilofnonprofits.org, http://nonprofittalentmatch.com.
The fourth way is to perform Internet search and research on non-profit or similar organizations that you might be interested in working with (criteria might vary from organization's size to industry focus or geographical locations). Based on the information presented  on their websites, make notes and then approach those organizations, directly inquiring or applying for positions of interest.
The fifth way is to consider various non-profit, for-profit and otherwise social good-themed data science-focused organizations, initiatives and Kaggle-like competitions, such as DataKind, DrivenData, DataLook and Data Science for Social Good.
Comment: Thanks, nice answer! Unfortunately I can not give point to that because I do not have enough reputation.
Comment: @user115415: You're quite welcome! No problem - feel free to upvote/accept, when you reach reputation of 15 or more (should be pretty soon :-).
Answer: It might be a good idea to start with voluntary work and see if that leads to payed position. DataKind, that has been mentioned above, is where I would start, especially if you live in England, since you can register your interest online and even do work with them as a data scientist for a weekend in a meetup event.
There are also various meetups in many cities where it's likely to find people working on nonprofit companies and expand your network.


Is there any use for the new HK-51 gear that was mailed if yours already came with gear?

Question: I understand that some people got a "naked" HK due to a bug, but mine came wearing a full set of Orange gear with blue 51 mods.  Does the "HK-51's Combat Outfit" that was mailed today with patch 1.5.2 contain exactly the same items?  It's BoL so I don't want to open it if I'll need it for an alt.  (Are the items inside it BoP, BoL, or BoE?  Do they sell for much?)
Answer: The bag it came in is bound to legacy, so you can transfer it to another character. That way you can send the bag to a low level toon you buy HK-51 for, then just replace the mods in his current gear with low level ones. If you hang onto said bag of gear you open it when you're 50 and you're set, not having to consume many bank spaces with gear you can't use.
Comment: Ah so if you buy HK-51 you don't get endgame gear in the mail for him?  Do you still get it if you acquire him the usual way on a lvl 50 alt?
Comment: I bought HK at lvl 1 and he came with his lvl 50 gear. just the same as if I had found him with my lvl 50.
Comment: @Matt Interesting, I assume the 50 gear is separate and not equippable?  Was it the same "Combat Outfit" bag?


Cooking at low temperature on induction cooktop

Question: I started cooking recently on induction cooktop ,minimum temperature on it is 120 C but i want to cook my dish at 50 C for 15 minutes but the temperature is increasing rapidly.How do i maintain its temperature?
Comment: 50 C is pretty cool.  That is more like warm for 15 minutes.
Answer: You can use a water bath and see if it will stay low enough for the desired time. You can play around with the water amount to achieve more consistency.
Even with the water bath, you won't get actual 50 degrees for 15 minutes, rather you'll have some slowly rising temperature which will stay in a hopefully acceptable range for the 15 minutes. This is because a cooktop is simply the wrong tool for the job, and especially the induction ones can be worse than the oldtime ones.
If you really want low temperatures for a sustained time, use an oven (if yours goes that low) or an electronically controlled cooking device.


Slow X-server performance over network

Question: I do my development work on a linux virtual machine on a remote computer. I'm using a Windows 7 laptop as my main computer, as it has more screen real-estate, and using Cygwin/X to run my GUI programs from the remote computer.
I've been struggling with the performance of this though, and I've tried a number of different approaches, with varying degrees of success.

Standard ssh X-tunneling
ssh X-tunneling with compression (-C) and faster cyphers (blowfish, arcfour)
Direct X client and server (ssh into remote box, run program with DISPLAY set to my laptop)

I've gotten all of these to work, but the performance has never been that great. The two computers are communicating over a LAN, connected by 100M ethernet. Watching the windows resource monitor, I find that the X server is never receiving more than about 100 KB/s under large screen refreshes.  I've done file transfers between these computers that go at about 10 MB/s, so I don't think there's a network bottleneck.
Security is not a concern, which is why I'm trying to avoid any encryption that would add overhead.
Why is the network performance so slow, and what can I do to improve it?
Answer: Might it be feasable to use VNC or a variant on the linux box ?
That might be faster than using the whole cygwin stack.

Slow X-server performance over network


Handing over manually logged in browser session to WebDriver/Selenium

Question: I need to automate interaction with a website that is initially protected with ReCaptcha. Can I initially manually log in to the website and solve 2FA, then hand-over the existing manually initiated session to the testing application to automatically run through the website tests with my manually authenticated session?
Comment: Just for reference, for connecting existing browser session, I believe the below two existing question/answer will be useful: [https://stackoverflow.com/questions/44277119/how-to-connect-slenium-webdriver-to-existing-firefox-chrome-browser-session](https://stackoverflow.com/questions/44277119/how-to-connect-slenium-webdriver-to-existing-firefox-chrome-browser-session) [https://stackoverflow.com/questions/44186595/connecting-selenium-webdriver-to-an-existing-browser-session](https://stackoverflow.com/questions/44186595/connecting-selenium-webdriver-to-an-existing-browser-session)
Comment: What language are you coding in?
Comment: Python, preferably.
Answer: I think it should be the other way around, letting the test hand it over to a manual users for a while:

Start the Selenium test to open browser and goto CAPTCHA page
Write a wait that waits for an element that would be shown after the CAPTCHA is completed. (Make sure this wait has a large timeout, maybe also enlarge the default timeouts. Be sure to reset default timeouts after your wait, if you change implicit wait your tests could wait for minutes when something is broken.)
Fill in the CAPTCHA manually
The test will see the element found and continue the test instantly, as it will poll for the element every 500ms by default.

Aslong the test is waiting for something you can just use the browser as normal.
Some reads:

Working with timeouts: http://toolsqa.com/selenium-webdriver/wait-commands/ (Guess the fluent-wait example is good to change from 30 seconds to 15 minutes, making sure you have the time to finish the CAPTCHA)
Official documentation on timeouts: http://www.seleniumhq.org/docs/04_webdriver_advanced.jsp
Comment: Perfect, thanks Niels. I'll give this approach a shot.
Answer: Firstly, this is maybe be a smell that your application is not built with a testability mindset.
In the Automation environment:
1 - This feature should be removed;
or
2 - The user should be automatically log by sending a token generated uniquely by the application, identifying therefore the user.
There are ways of working around the issue, but this way you would still have an application difficult to test and probably your tests would take longer to run.
Attack the disease, not the symptoms.
Comment: Good point - but sometimes in dysfunctional situations the testing team can't perfectly dictate the testing environment, or a quick hacky approach is needed to test the 'internals' w/o disabling the initial security. Generally speaking though I think you are very right.


Strategies for improving timing

Question: Good day, wise musical people, I am a late starter to music but one of the things I am struggling with is keeping proper time in my music. I can sing along to songs on the radio and generally keep time with them but I'd really like some exercises I could do to really get this. I play a wind instrument so it's like - jeez, I have to remember the fingering and breathe and keep time ..WTF! So how can I break it down so that I can have a 5 minute exercise I can include in my practice or even when I am driving to improve this? Thank you :-)
Comment: Please check out the 'related' questios on the right of the screen. There have already been several similar, with great answers.
Answer: Singing along to a song is fine but it doesn't focus on the timing.  Its better to beat out the pulse - not the rhythm, but the pulse or beat - of the piece whilst you listen to it.  You can do this by clapping, tapping your feet or whatever but do it and keep it strict. Most popular music keeps to a very even tempo so this is usually straightforward.  Very soon and you will get used to feeling the pulse of a piece and staying in time will become easier.
It certainly worked for me as a child.
But don't do it, especially the feet, whilst driving.
Comment: Thanks for all the suggestions. So what I reckon I am going to do is get my metronome, take a scale and play it with the metronome, record it and then listen back to it to see where I am going astray. The plan is to make this part of my regular practice session..

Strategies for improving timing


What is a "feature flag"?

Question: High Scalability mentions feature flags here:
5 things toxic to scalability, "5. Lack of Feature Flags"
What exactly are feature flags?
Comment: As Maxim Vexler points out, this Flickr post is one of the canonical, early articles on feature flags, and explains their use and implementation in some detail http://code.flickr.com/blog/2009/12/02/flipping-out/
Answer: A 'feature flag' (or Feature Toggle) is the ability to turn features (sub-sections) of your application on/off at easily:

perhaps via a re-deploy, or
some internal page where pages/features can be toggled live.

I guess the example there was that it's handy to have the control to reduce the feature-set somewhat if you need to, say, reduce db queries if the load is too high.
There are heaps of other reasons you would want to use this though - one of the main being enabling Continuous Delivery: pushing things into production/live yet having the feature disabled/toggled until it's completed. We often use what we call a 'dev cookie' to show uncompleted features to just the dev team. This way we can test partially completed work in production (oh yeh! is there better integration?) over multiple releases/deployments before we 'untoggle' (completed) it and it becomes visible to the public.
Here's a simple package that helps you do this in ASP.NET MVC land: https://github.com/cottsak/DevCookie (full disclosure: I'm the author)
Fowler also has a much longer article than the one linked above with a lot more details.
This post (on Fowler's site also) explains the various types of toggle strategies. DevCookie supports the mainline/trunk-based strategy and is called a "Release Toggle" in the article.
Adil's answer highlights that there are many terms and reasons why you might want some of this infrastructure. Keep in mind you may only need some of these things. For example, I may only want to enable a simple, and agile deployment/delivery workflow and so a simple infrastructure will suffice. If you then choose you want to move into full #leanstartup experimentation with A/B, cohort testing and things like controlled roll-out, you should consider an analytics tool (e.g. Heap) which facilitates those data-driven development methodologies as a distinct solution. A toggle infrastructure that does all of the above will lead to bloat and unnecessary complexity.
If you made it this far, then you might like to check out some of my other thoughts on Mainline Development, feature toggling, and other silly ideas like TEST, QA, SIT, STAND, CROUCH.
Answer: Feature Flag is a technique to turn some functionality of your application off, via configuration, without deploying new code.
Feature flags play a key part in CI scheme where features are constantly being deployed but not necessarily "released" into production.
More info here:

http://code.flickr.com/blog/2009/12/02/flipping-out/

-- EDIT:
Feature Flags java implementation.
Comment: This is well described in 'Continuous Deployment' and is pretty much a requirement for 'mainline' development. Rather than branching in SCM for features, features get turned on or off, allowing you to release code with features that shouldn't be enabled yet.
Comment: I work for https://ConfigCat.com and the way I see it "changing a config, without deploying new code" means that the configs are served by the feature flag service and your application accesses the values by pulling that config file. This way you can be sure that changing a value does not need any kind of re-deployment of the app.

On top of that it lets you create rules so you serve a value to one user and a different one to another. cool is all the feature flag evaluation is on the client side and all this logic works without the need to push any data back to the feature flag service.
Comment: Just a note on "via configuration, without deploying new code": it appears that the statement means changing a config and then deploying the app again (even tho perhaps no code has changed). This can still take anywhere from seconds to minutes depending on your deployment pipeline. A Feature Flag or Feature Toggle may not be persisted in config. It could be in a store/db somewhere and behave in a "live" fashion - ie, navigating to some admin page where you bang on a button to enable some behaviour site-wide instantly (no deploy, no config change).
Comment: http://techblog.outbrain.com/tag/feature-flags/ - Url is not working
Answer: Feature Flags, feature toggles, experiments, and controlled rollouts are synonyms for a simple yet powerful idea: separate code deploys from feature rollouts. In plain speak, it's the ability to push your feature's commits to production while choosing who amongst your customers - if anyone at all - gets to see that feature.
They were popularized in part by Facebook's Gatekeeper. LinkedIn's LiX is another good example.
Embracing this simple idea lays the foundation for many best practices, including:
Continuous Deployment/Delivery - multiple code pushes to production in a day.
Trunk/Mainline Development - feature branches should be created only for pull requests, not for long lived feature development.
No More Release Trains to bog things down.
QA/Perf Testing in Production - real QA and performance testing is on production infrastructure with production traffic. Don't waste time building extensive performance labs and staging environments.
Experimentation - know how a new feature moves the needle on your KPIs.
Avoiding Hotfixes or Code Rollbacks when Problems Happen - both hotfixes and code rollbacks are stressful, take a long time, and lead to more problems than necessary. Instead, turn the feature off or ramp it down.
Others have mentioned open source libraries. A good example of a full solution - like Gatekeeper and LiX -  is Split. I work for Split.
Comment: I think it's important to not conflate feature flags solely to support CI verses AB/cohort/lean experiments - the goals are different. For example, using a feature toggle to get something into Prod for QA/acceptance might be a simple tool to aid CI/CD and in such a case Split could be overkill. Then again if you want to do lean experiments or A/B testing then you possibly need a good analytics tool like [Heap](https://heapanalytics.com/) with the additional tooling and telemetry reporting built in. I don't like the idea of merging these two objectives - seems like you could bloat very easily.
Answer: There are a lot of great answers here, all driving at the important, basic definition popularized in the Martin Fowler post:
They're bits of code that "[allow] teams to modify system behavior without changing code."
So we've historically thought of them as represented by the pseudo-code:
if(app_settings["beta-mode"] == "true")
  showAwesomeNewGui();
else
  sameOldSnoozeFeset();

That's a totally accurate way to think of it, and both Matt and Adil expand on it nicely with a variety of tactical use cases for the feature flag.
But I'd like to offer a revised definition that reflects how reality has evolved in the six years and change since dotnetdev asked the original question.  I work for Rollout.io, a feature flag platform, so I've had a front-row seat for this evolution.
Simply put, feature flags aren't any longer just a way to turn bits of functionality on and off in your application.  That's like answering "what is an invoice line item" by saying "it's a description and an amount of currency."  True, but it doesn't drive at the broader point of the invoice itself.
Feature flags are the tactical bits of an overarching strategic solution in modern software.  They're the means by which you defer important decision logic in your code until runtime when you have more information.  And, perhaps most importantly, they don't just occur in isolation any longer, with a single check to see if the version number is greater than 2.7 or not; organizations that use them are typically including them as part of a comprehensive, system-wide product approach.
As others have mentioned, Facebook and LinkedIn pioneered this, but in 2018, a whole lot of organizations are doing it.  They're deferring decision logic questions for runtime as part of development strategy, operations strategy (or DevOps strategy, if you want), and product strategy.  Here are examples of such questions.

Who should see the new admin screen that we're rolling out, and when?
What level of membership is required to unlock this Easter egg?
When should we cutover to the new database?
Should we put a picture of a cheetah or an eagle on the checkout button to enhance conversions?

To have an application that defers a significant number of such decisions until runtime, you can't throw feature flags into your application in ad-hoc fashion or you'll bury yourself in technical debt.  You need, these days, to have a comprehensive feature flag management strategy, which includes a few different components.

Toggle points are used to switch behavior for new features.
Multiple toggle points come together to form a toggle router. A toggle router determines the state of a feature.
Toggle context provides the toggle router the necessary contextual information (e.g., specific user).
Toggle configuration provides the toggle router information about the environment.

So, in the end, what are feature flags?
Well, they're an important part of a broader strategy to having an application that's adaptable to both technical and market needs.
Answer: A feature flag (also known as feature flipping or feature toggle) is a switch to enable or disable a potentially expensive feature as needed (like, say, when a site is being hammered with unexpected traffic). This'll buy you a little time until you scale up, or until the load spike goes away.
Here's an example from the SWIG documentation.
Comment: That is one use of feature flags, yes, but the big concept to understand is that they decouple feature release and code deployment, so that you can release features whenever you want, instead of whenever the code happens to ship. It's a cornerstone of continuous integration.
Answer: At my company we used to have an own solution for that. We created a service providing a downloadable config (.json) file for every apps.
In that config we stored the flags for the features. Based on that config the app can show or hide the current feature.
(For example show or hide a menu item on the sidebar).
We also created an internal admin page where we can configure the feature-flags.
It worked quite good for a while but after that we would have liked to do user targeting and A/B testing.
To develop by own It seemed too much effort, so we chose a third-party solution.
As already mentioned here there are many solutions for that.
We chose ConfigCat because it supports customized target groups and percentage-based rollout at once. You can check the supported open-source sdks on github.
Answer: Feature flags (or feature toggles) allow you to enable features remotely on an application without needing to re-build/re-deploy the application.
This allows you to deploy the code to production but not release the feature until you are ready.
You are able to target specific users, so you could enable a new feature to your beta users to test.
At our company we've previously used LaunchDarkly and other suggestions from FeatureFlags.io. We've also tried to use Firebase's Remote config to try and make this work however we found it wasn't really fit for this purpose.
We ended up developing our own version called Bullet Train, which we've open sourced. It combines both Feature Flags/Toggles and Remote Config.
Answer: Feature Flags are used for several purposes.
The general idea is to delegate control over which user sees what feature to some remote dashboard or back-office of some sort.
Once a feature is flagged in the code you can now use several methods to determine which user sees it in your application:
 1. On/Off - show the feature to all or none of your users.
 2. Gradual Release - show the feature only to a percentage of your users, then gradually show it to all users.
 3. Targeting - show the feature to specific users based on properties or characteristics of that user.
Tools that help with controlling Feature Flags (booleans) and Feature Configurations (strings, numbers, etc) are usually called Feature Management Platforms
There is a great service for Feature Management called Configz.io
Answer: My understanding is that feature flags help you gate functionality by deciding which users receive certain features.
For example, let's say you only want your beta users to see a new feature. You would "toggle" that feature on for beta users and the rest of your users would not see it.
LDUser user = new LDUser("firstname.lastname@example.com");

boolean showFeature = ldClient.toggle("your.feature.key", user, false);

if (showFeature) {
     // application code to show the feature
 }
else {
     // the code to run if the feature is off
 }

I'm testing LaunchDarkly's feature flags for some front-end JS A/B tests - seems to be working well. You can also check out this site for feature toggles and feature flag libraries.
Answer: From a coding point of view a feature flag can be as simple as an if statement which wraps around a new piece of code which you are writing. When the if statement evaluates to true (the feature flag is on) then the new code will be executed.
In a real-world example of delivering software, the if statement described above would evaluate differently depending on environment the software is running in. For example if the application is being executed on your QA server the feature flag will return true and the new feature will be seen. If it's being executed on your production server the feature flag will return false and the feature will be hidden.
From my personal experience during my career I have used feature flags in the following ways:

Decoupling code deployments from releasing of features to customers. This was my first initial use of feature flags in our development process. We used it to remove the dependency between our marketing and product team and the engineering team that was doing the development and releases. Feature flags allowed us to deploy our code weeks in advance of a launch whereas previously we were deploying code the night before a release!
Testing in production. Before we used feature flags when we released our code it was an all or nothing event, either all our customers got the feature or none of them did. We used feature flags to allow us to roll out a new feature to a small percentage of the users at a time. This allowed us to collect valuable feedback and data about a new feature without risking any potential issues to the entire customer base.
Enabling/disabling a feature per environment in the development life-cycle. We used this extensively in development for allowing a much smoother deployment process - we have a CI/CD pipeline in which the use of feature flags is vital.
Creating a kill switch. We have wrapped certain features of our application with a feature flag which allows us to 'kill' that feature in the event of any issues we are having with the application at the time. For example if we find ourselves under heavy load we are able to turn off certain non-essential features of the website to help with the issue.

You can read more about feature flags here.
You can add feature flags to your code in multiple ways.

You can create your own or use a third-party feature flag library and add your feature flag data into a config file which can be included in your deployment package.
You can create your own or use a third-party feature flag library and add your feature flag data into a config file which can be loaded at run-time.
You can use a cloud-based feature flag management service to manage all your feature flag needs for you.

Writing your own library may seem a good idea at first and usually it can start out that way. However you can soon run into issues when you want to implement the more advanced use cases of feature flags like rolling out to a percentage of users or targeting specific user groups. Another issue with creating your own feature flag implementation is if you are using multiple languages you will need to implement your code multiple times.
The best and easiest way to use feature flags is to use an online feature flag management service such as Floodgate. This way you can leverage on the platform to all the heavy lifting which then allows you to concentrate on creating the feature for your application.
Here is an example of how to add a Floodgate feature flag to an application using the .NET SDK.
using FloodGate.SDK;

var floodgateClient = new FloodGateClient("API-KEY");

var flag = floodgateClient.GetValue("a-new-feature", false);

if (flag)
{
  // Execute the code for my new feature here...
}

If you are working in a development team and you are not using feature flags and you are experiencing issues in deployments and code management within the team. Using feature flags can be a great way to resolve these issues. There is also a nice side effect of feature flags speeding up your teams development velocity.
Martin Fowler gives a very in-depth write-up of feature flags here which I recommend you to read.
Answer: Feature Flags basically gives you the ability to turn on and off a feature without making any changes on the code or releasing a new version.
It's an important solution especially for mobile application developers since they have no control on users to update their application to a new version.
There are several companies giving this service for mobile application developers.

apptunnel.com
apptimize.com
launchdarkly.com
Comment: As an addition here is a comparison of the best current feature flag services: https://featureflagservices.io
Comment: Be wary of these. You don't need to integrate one of these services to create a simple switch which can be used to hide multiple features from PROD visibility/integration. You also don't necessarily *need* to do this live - as in, waiting for a deployment isn't a big deal when a PROD deployment is only minutes (which you should be optimising for for many many other reasons).
Answer: At my company we use feature flags for every new feature we introduce in our SaaS app. Apart from the benefits to performance it also allows us to roll out new features gradually - introducing new features to power users first, getting feedback from them and improvising it before we can roll it out to all users.
It also allows us to customize offering to individual users - power users want all features; simple users may just want the basic stuff and may get confused by all the powerful complex features. It also allows our sales team to up-sell.
And of course as others have pointed out, if we find a feature is causing a performance degradation, we can simply turn off that one feature (either for all clients or for the one client who is causing an issue).

What is a "feature flag"?


Maximum likelihood estimation get biased by fat-tail samples identifying mixture model of 2 normal distributions

Question: I'm building a mixture model consists 2 normal distribution:
\begin{equation}
X_1 \sim \mathcal{N}(\mu_1,\sigma_{1}^{2}), \quad X_2 \sim \mathcal{N}(\mu_2,\sigma_{2}^{2})\end{equation}
while
$$pdf(x) = p_1 N(x, \mu_1, \sigma_1^2) + p_2 N(x, \mu_2, \sigma_2^2)$$
where $p_1+p_2=1$,
and  $N(x,\mu,\sigma) = \frac{1}{\sqrt{2\pi \sigma^2}}exp(-\frac{(x-\mu)^2}{2\sigma^2})$.
With samples ready, I'm beginning to fit $p_1$, $\mu_1$, $\sigma_1$ and $p_2$, $\mu_2$, $\sigma_2$.
First, I defined a very simple fitting way, by frequency count.

I split the range of $x$ to different bands, each band's width $w=\sigma/10$, where $\sigma$ is the standard deviation of the samples.
I count the frequency of $x$ in each band $Freq_i = \text{Sample Count in band_i} / \text{Total Sample Count}$
I defined the target as $Target_{FreqFitting} = \Sigma_i{(Freq_{i, sample} - Freq_{i, model})^2}$

Using excel "solver" to solve the problem, it looks nice:

Here the black line is the samples' frequency; solid blue line is a normal distribution model sharing the same $\mu$ and $\sigma$ of the samples, it's not close to the real samples; red line is the result of Gaussian mixture model, while the dotted lines are the two components.
Then, I went to Maximum Likelyhood Estimation. It turns out a surprise.
The target is $Target_{MLE} = \Sigma_i{Ln(pdf(x_i))}$. The result is quite disappointing:
The green line is the result of MLE fitting, it's way too bad.
After checking the details, it seems that MLE optimize for samples that are far away from the mean - the target gain from $x$ beyond $[\mu-3\sigma, \mu+3\sigma]$.
Thirdly, I manipulated the MLE target functions a bit:
$Target_{AdjustedMLE} = \Sigma_i{\frac{Ln(pdf(x_i))}{1+a((x-\mu)/\sigma)^2} }$
If I choose $a=0.5$, it fits well:

Is this a weakness of MLE?
Do you guys meet similiar problem using MLE? how do you achieve a good fitting?
Answer: No answer yet too, but how do you account for the constrain p1 + p2 = 1 in your max likelihood estimate ?
I would replace $p_2$ by $1 - p_1$ in your model and fit only $\mu_1$, $\sigma_1$, $\mu_2$, $\sigma_2$ and $p_1$.
Comment: yeah $p_2=1-p_1$, and also $p_1 \mu_1 + p_2 \mu_2 = \mu$. in excel i just put the formula and let the solver try.
Answer: no answer yet. Just to say i put a threshold of the pdf, which i chose to be pdf of normal distribution at 6 sigma, then anything below the threshold, will be assigned as the threshold's issue. in this way i managed to suppress MLE's focus on outliers.


Cannot offset path in Illustrator CC

Question:
I am trying to offset a path and it is not working.  I believe my problem lies where it says "type".
Comment: Are you trying to offset your path using Object > Path > Offset path or something different?
Answer: Maybe there's a mistake. Look at your image, the top left info is about character and paragraph, this never appears when a shape is selected.
Here two apparent equal paths:

When the green is selected, the top left indicates this is a Rectangle.

When the red is selected, the top left indicates Type, because is a Text Frame. If you touch a shape with the Text Tool immediately is converted to a Text Frame. That's why you can not do some modifications.

To make changes to a Text Frame Path, select it with the Direct Selection Tool, the white pointer.
Comment: ok got it.  i knew there was a simple solution.  i spend 'so much' time trying to figure it out.  thank you!

Cannot offset path in Illustrator CC


Mass assignment problem when instantiating a model

Question: I have a User model (Devise) and have created a Profile model with has_one / belongs_to relationship. I'm trying to automatically create a profile when the User is created as follows :
class User < ActiveRecord::Base
   has_many :videos, :dependent => :destroy
   has_one :profile, :dependent => :destroy

    after_create :create_profile

  # Include default devise modules. Others available are:
  # :token_authenticatable, :encryptable, :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable, :confirmable

  # Setup accessible (or protected) attributes for your model
  attr_accessible :email, :password, :password_confirmation, :remember_me

  protected

  def create_profile
    Profile.create :user_id => self.id
  end

end

The profile gets created but the user id does not get populated. I get a Mass Assignment warning with regard to setting :user_id on the profile because I have attr_accessible exposing a few fields on the Profile.
I dont want to remove the attr_accessible but dont understand why setting one field is considered mass assignment. I figured this might be to do with passing a hash so Ive tried the following as a workaround :
@profile = Profile.create
@profile.user_id = self.id

This removes the warning but the user_id is still not getting set on the profile. What is the correct way to go about solving this ?
Any clarity much appreciated ! :)
Answer: Are you calling @profile.save at the end of your workaround?
Maybe you can try this:
def create_profile
  self.build_profile.save
end


Connection between 'proxy', 'pronumeral' and 'pronoun'?

Question: I was thinking about the words pronumeral and pronoun; I realized they both share a prefix, and are both proxies for numerals and nouns. I was wondering if there is any connection between the words since proxy also begins with pro. If proxy is unrelated, is there any reason for the two words to start with pro?
Comment: I've never heard the word 'pronumeral' before. It seems to mean 'variable' in mathematics. Where have you used the word before?
Comment: What did the dictionary say?
Comment: @Mitch I'm a mathematician and a programmer, so I use the word all the time.
Comment: @annonymously: does it mean anything -different- from variable? Is it a variable of type integer?
Comment: A pronumeral is any letter that replaces a number (or other object like a vector), that is used to generalise a formula or equation, so that it can be valid using any appropriate object.
Answer: According to the Oxford English Dictionary, one of the senses of the prefix pro- is:

Prefixed to nouns to form nouns and occas. derived adjectives with sense 'deputizing for, standing in place of'.

This is the case of pronoun and pronumeral. The etymology for this particular sense is:

in these, Latin prō- in the sense 'for', 'instead of', 'in place of', was prefixed to a noun, apparently originally in prepositional construction, as prō consule (one acting) for a consul, afterwards combined with the noun, as prōconsul proconsul n.1; so prōflāmen deputy flamen (compare flamen n.), prōmagister deputy head (compare magister n.), prōpraetor propraetor n.; also in a few names of things, as prōnōmen pronoun n., prōtūtēla deputy-guardianship (compare tutelage n.).

Now, what about proxy? The OED says that it was originally a form of procuracy, which is

the office, action, or capacity of a procurator (procurator n.1 1); management or representation on behalf of another.

The etymology ties this to the Latin prōcūrātio. EtymOnline provides some context into this, citing:

c.1300, "bring about, cause, effect," from O.Fr. procurer (13c.), from L.L. procurare "to take for, take care of," in classical Latin, "manage, take care of;" from pro- "in behalf of" (see pro-) + curare "care for" (see cure).

So, proxy, pronoun and pronumeral do all share the same prefix pro-, although proxy came about its pronoun through procuracy.
Comment: `s/share the same pronoun/share the same prefix/`
Comment: @tchrist Thanks, edited. Too many "pro-s"
Comment: Still too many "pro-s"!  s/profix/prefix/


I want to take photo of moon with my mobile camera?

Question: I tried taking pic of moon with my mobile camera, i tried auto mode and manual mode also. but its not clear. what are different option or addition tool required.
Comment: Does this answer your question? [How to take photos of planets with smartphone?](https://photo.stackexchange.com/questions/99963/how-to-take-photos-of-planets-with-smartphone)
Answer: Unless you have a multi-camera phone with a very strong telephoto option, the moon is much too small in the frame to give usable results even with modern, high resolution sensors.
A single camera phone will have something like a 24mm or 28mm equivalent lens. Which will make the moon look tiny in your frame - digital zoom will only help you magnify it a few times before you run out of resolution reserves.
DSLR/DSLM/superzoom users use 300mm to 1000mm equivalent lenses for good moon pictures...
Comment: Unlikely to find a phone (unless you rent it with a contract) that is better at moon shots and cheaper than a basic secondhand DSLR with a basic long focus prime...
Comment: I have moto g5s+ phone which is dual camera, Will this phone work?
Comment: This is a main+selfie phone... I did mean the kind with 3 or more main cameras....
Comment: which phone would you suggest me to buy which is good for photography , I cannot afford a DSLR camera at this moment.
Answer: It's sort of unexpected but the moon is really small.  Phone cameras are not really useful here; you want equivalent focal lengths of 600mm to maybe 2000mm.  You do not need or want a DSLR for that: older superzoom or hyperzoom cameras with small sensor (the current standard for "small sensor" tends to be 1/2.3") behind a long lens will do the trick and will neither bust your budget (specifically since you are thinking about buying a used smartphone insteaed) nor your arm strength.
Of course, mounting a more ordinary camera (assuming you get it to mount) behind an ordinary telescope will allow you to do astrophotography reasonably well.  Like with mounting a camera on a microscope, being able to use general purpose optics rather than something specifically fit to the camera may give you a solution without special purpose pricing.
Answer: You should try manual focus, the first time I tried to take a pic of the moon with my iPhone the moon was blurry until I figured out the autofocus was not working, you need to focus at the infinite, try to focus on a street light that is at least 5 meters away
Answer: Instruction may vary as each version of Android may be slightly different:

On the left taskbar you'll see a JPG icon. Tap thereon and it'll switch to RAW JPG. this may allow corrections to be made to the image after the image has been taken.
Change the Exposure Value by tapping the EV option on screen and selecting a coffee exposure.
Select the ISO option and choose a worth of between 80 and 100.
Increase the shutter speed, using the S option on screen, and choose the longest option. this may take longer to require the photo so staying still is crucial .
Take your shot! Once you're pleased with the way your image appears on the screen, click the circular capture button at the bottom of the app.
Comment: what's a "coffee exposure" and why would a long exposure time be necessary for a moon shot?
Comment: Thank you, i will try and show u result.


Betterment on F-1 VISA and where to report 1099-B and 1099-DIV forms

Question: I am a student on F-1 VISA and I decided to try out Betterment. Now for a meager sum of less than 100 dollars a month, I was just checking out how the investment works. At the end of a year, I got the 1099-DIV and 1099-B forms. Every year I fill tax forms using the f1040 NR-EZ form as I have no dependents. Would anybody have any idea on which forms I should use for this? Also on the 1099-B there was a short term summary and a long term summary. Now the long term summary was just zero everywhere, so not sure how to include all of those on the right forms. I'd be glad if anybody has any pointers to this.
Comment: They only become an issue if they are above a certain amount, otherwise they are for all intents and purposes ignored as they don't factor in how much you owe or get back. It only becomes an issue if you make back something considerable (capital gains) and then you report it, but you have to use 1040A (not EZ) and there is a worksheet for it. If you qualify for EZ, and your "investment earnings" are less than the base, then you are pretty much set. Give this a read: https://www.irs.gov/uac/Reporting-Capital-Gains
Answer: You should be using the full 1040NR, not the EZ version. Dividends (from 1099-DIV) go on line 10, capital gains (from 1099-B) go on line 14. Read the instructions whether you need to attach Schedule D or not.


Is monerujo wallet legit?

Question: I recently worked with the Monerujo android app and noticed its strange behavior.

Creates the receive address after connecting to the Internet. This is while the receive address can be generated offline. (It seems that the app developer intentionally wants the user to connect to the Internet)
Synchronization time is very high, it syncs approximately more than two and a half million! blocks with high data usage!. Very very slow!.
Initially there is no node by default. And after entering node, again, the app intentionally wants the user to connect to the Internet.

Is monerujo wallet legit?
Answer: yup, no issues.  Same with cake wallet.

Is monerujo wallet legit?


Should I add my blog posts as regular HTML pages on my website

Question: I have a main website (http://www.example.com) and a blog (http://blog.example.com), the blog is powered by Blogger. Sometimes users may do a search and it brings up the blog page but I think it would be useful if the search took the users directly to my website. Would it be a good idea to replicate my blog articles as HTML pages.
Comment: Maybe blogger just doesn't give you enough control over the additional content on your blog pages?   Have you considered using a different blogging platform such as installing WordPress?
Comment: I know its very popular but the way it uses mysql is just horrible.
Comment: Technically, a blog subdomain already is part of your website, even if it is hosted by some other company.   How would it be more useful to users to land on the same content, but in the main section of your website?   Would the navigation be different?   Does blogger add a lot of cruft onto the page?    If you are publishing the content in the main section of your site, why would you continue to use blogger at all?
Comment: @StephenOstermiller if it was part of main site then headings etc would more likely push user to explore software pages but also could add pages comtaining lists of related articles making it easy to navigate. But main reason is I hope that more pages mean my software is more likely to come up in response to user searches. But blog is good for existing users who like to follow the blog and read articles as they are created, it is also easier to create pages using WYISWG blog first rather than creating html page each time.
Comment: Bit late to change blog, but also I really dont like the architecture that wordpress uses, very flakey.
Comment: @PaulTaylor no, it isn't too late to change.  Importing blogger to WordPress is easy peasy.  And WP is hardly flakey, it powers about 30% of the web - I run a webhosting business, WP is actually quite robust..
Answer: I probably wouldn't replicate your articles, as there isn't much purpose in having them in two places. However, you could consider moving your blog to your main domain if Blogger does not give you enough flexibility.
This is really a question about whether Blogger suits your needs or not. If not, move your blog to a different provider or even just to static HTML on your main site like you mentioned. If you do, then 301 redirect the old article URLs to the new ones so that they keep most of their rank in search.
Comment: That part of the question is easy to answer:  it will hurt SEO.   Google will identify them as duplicate.  Google will only index one of the two. In the worst case, it will make your site look low quality and hurt the rest of your site.   See [What is duplicate content and how can I avoid being penalized for it on my site?](https://webmasters.stackexchange.com/questions/35652/what-is-duplicate-content-and-how-can-i-avoid-being-penalized-for-it-on-my-site)
Comment: Hmm, it was meant o be a question about whther having two versions of an article can improve SEO
Comment: As Stephen said, don't have two versions of your articles that are both normal web pages. Nothing good can come of it.
Comment: So assume I used wordpress and could embed into my site rather than different subdomain I still think it would be very different to present as a series of blog articles in chronological order and as a series of landing pages where they act as the first page a potential new customer sees. So if i adjust the question somerwhat to mean that I just want to reuse the content of some blog posts to act as landing pages can I do that without incurring any duplicateion issue.
Comment: the link you provide is focussed on copying pages from other sites rather than reusing my own content.
Comment: My other issue is that the blog has posts for two different but similar products.
Comment: @PaulTaylor Since the scope of your question changed so much, the best way to get help from here on out would probably be to post a new question with the new details, then link the new question in a comment in this thread. Thank you!
Answer: The easy way out is to use a theme for your blogger which includes a navigation bar similar to your website.
In such a case, people would not know the difference (generally speaking) - if users are on your website they will click on "blog tab" to navigate to blog - when users are on your blog - they can click on "website tab" to navigate to website.
Don't replicate blog content unless you are planning to retire the separate blog completely and make your website your primary blog.
Comment: Although I think the OP is probably referring to the different hostnames, rather than just the look & feel of the site - which might be reasonably seamless anyway; the OP hasn't mentioned that aspect.