What is the birth-place of Sri Chaitanyadeva?

Question: There are "birth-place" temples of Sri Chaitanyadeva at Navadvip and Mayapur,one at the east side and another at the west side of the Ganges.Which place seems authentic? I am interested in knowing the reason.
Comment: Nabadwip Dham is the birthplace of shree chaitanya mahaprabhu.. There is no proper evidence about Mayapur's birthplace..
Answer: A study was carried out by Professor K.N. Mukherjee of Calcutta University, in the 1980s, to ascertain Sri Chaitanya Mahaprabhu's birthplace, a few years back. It was the first ever non-Vaishnavite impartial scientific study ever conducted to determine Mahaprabhu's birthplace.
The findings of this investigation can be summarised as follows:

From Rupa Goswami's 8 couplets on the glory of Navadvipa it appears that Navadvipa the place of birth and play of Sri Caitanya, was extended from the beautiful large tank (Dighi) to the Ganga. The maps and records refer to the only dighi in the area and that is the Ballal Dighi in Mayapura.

There is no reference to Mayapura or Nava Dvipas in any contemporary literature or Purana. Navadvipa and Nadia (or Nuddeah or Neddia) were one and the same place, the capital of Bengal of the Sena Kings. At the time of Sri Caitanya it was a forsaken, plundered, desecrated and decaying city. The palace of the Sena Kings (may be belonged earlier to the Buddhist Pala Kings also) is still lying in ruins as Ballal Dhipi near the Dighi.

The tyrant Chand Kazi resided at Kazipara of Simulianagar (in present bamunpukur) of the old Navadvipa City. Through Chand Kazi's tomb there is a massive very old champak flower tree grown, proving the grave to be very old.

Muslims in the Kazipara and Mollapara being disturbed by loud kirtana even in the night from Ramchandrapur, more than 6 km away, is absurd, but it could be possible from Mayapura only 1 km away.

The vivid description of Nimai's (Sri Caitanya) protest kirtana procession from near his residence along the bank of the Ganga to Kazipara, referring to all the bathing ghatas on the way, did not mention Nidaya ghata (opposite Char Nidaya). Nidaya ghata should have been mentioned if the procession started from Ramchandrapur area. But no mention was needed if it started from about the Yogapitha temple in Mayapura, when Nidaya ghata would remain in the opposite direction of Kazipara.

When Nimai left his house to go to Kantaknagar (Katwa) for his sannyasa, he crossed the Ganga at Nidaya ghata, which is far to the NE of Ramchandrapur in opposite direction of Katwa; Nimai could very well cross over from the ghata near his house at Ramchandrapur (much nearer to Katwa). On the other hand from Yogapitha in Mayapura it was more convenient for Nimai to move westward to Nidaya to go to Katwa.

Even when the first concept of Mayapura and Nava Dvipas were propounded in early 18th Century by Narahari Cakravarti, he vividly described Antardvipa to be in the east and Rudradvipa in the west. But Smythe and other map makers showed Rudrapara (Rudradvipa) to the NE of new Navadvipa city as well as of Ramchandrapur (at the centre of Antardvipa?) and not to the west. Whereas Rudrapara remains definitely to the west of Mayapura, conforming the to the description, while the old Ganga flowed in between the two.

A very rare genuinely old (500-600 years) idol of Adhoksaja Visnu was found in 1934 buried in the mound at the present site of the Yogapitha temple of Mayapura (Kedarnath Datta died in 1914). Adhoksaja Visnu was described as the family deity of Nimai's house. It is so rare that neither any such idol was as yet found anywhere else in Navadvipa area, nor was it referred to in any of the historical volumes on Bengal. The idea that somebody kept it concealed from Ramchandrapur for over 400 years to bury it opportunistically at the very place where Yogapitha temple in Mayapura was to be erected is farcical.

The author (a pedologist) found the soil in the Mayapura area to be very compact, deep and humus clay, indicating rather old land formation. But in Kankrhar Matha (Ramchandrapur) north of new Navadvipa, in old Ganganagar (Bharuidanga), present Srinathpur (near Gurhgurher Khal) etc, the soil is distinctly layered fine and coarse silt, indicating that the area was in the bed of the river in not too long past. So, original Navadvipa, being a very old city, should have its area to be of hard clay by now.

Smythe's map showed in 1855 Ballal Sen's old Rajbari (palace) in Bamunpukur and Ballal Sen's old Dighi in ballaldighi mauzas Hunter's Account mentions definitely (1873) Chand Kazi's (Maulana Serajuddin) tomb being in Mayapura.

The 1958 air-photo and thorough ground-survey based map clearly indicates the location of Ramchandrapur to the SW of Rudrapara and Char Nidaya, while Mayapura further to the east of Rudrapara-Nidaya. Both Hunter in 1875 and Survey of India in 1958 referred to Mayapura in its correct spelling and not in the Muslimized form of Meyapur as given only in 1922 edition map.

Therefore, the evidences are very heavy in favour of Mayapura centering at Yogapitha area as the place of birth of Sri Caitanya. The author's considered opinion is that every inch of the old Navadvipa City could be considered as the birthplace of the great savant. The author's conception of the location of the old Navadvipa city and the layout of the Ganga at the time of Sri Caitanya (15-16th Century), based on palaeo-fluviometry. As the old city was extended from Chharh Ganga to Kazipara-Mollapara, Ramchandrapur may be considered as part of the old Navadvipa-dhama. Anyone may raise a temple on any area of the old Navadvipa and may tell that his temple is located in the city of birth of Mahaprabhu. As Basak (1981) has rightly stated, there is no point to quarrel over the issue, when Vaisnavas throughout the world are famed for their humbleness.

You can read more about the study in the article here.
Comment: yesi read this long ago on net.i could not believe in the fact that the deity of Vishnu wd be abandoed by His family,I also found that Ganga has changed its course and so the logic seemed untenable.Further, the realised saints like Sri Ramda Babaji accepted tye Prachin Navadvip as the birth-place. I value the value of the saints far more than the value of tge scholars.No recognised saint of Bengal upto Sri Mohanananda Vrahmachari, Maa Anandamoyi and Sri Omkarnath seem to have ever visited Mayapur even once, even though they went to Navadvip many times.
Comment: And Mahaprabhu's family was Shakti worshippers by the way. So at best they could have a Shalgram shila.
Answer: Premananda Bharati was the first person who went to the West to preach the religion of Love of Mahaprabhu.He came to enquire about the original birth place of Mahaprabhu to Sripad Ramdas Babaji, a Siddha Vaishnava and the pontiff of the Radharamana Charandas Babaji lineage. Premanandaji was sent to Him by Sripad Premananda Goswami,Sripad Nilmani Goswami,Sripad Haridas Babaji Maharaj,Sripad Jagadish Das Babaji Maharaj and other Vaishnava Mahatmas residing in Vrindavan.

Babaji Maharaj told them very humbly that Mahaprabhu's birth-place was in the northern part of Navadvip, at the Vaarakona of Vaidik-para.There was a broad roadway going in font of Mahaprabhu's house to the ganga-ghat and just on the opposite side of the bank was the way to Katoa. According to Sri Chaitanya-Bhagavat of Vrindavan Das, Mahaprabhu crossed the ganga from the Baarakona ghat and came to Kantaknagar. That ghat has been named 'nidayaar ghat' (the merciless ghat) from that day. Some part of Mahaprabhu's house was devoured by the Ganga.But the siddha Mahatmas like Jagannathdas Babaji and Chaitanyadas Babaji were engaged in spiritual practices at Navadvip,being sure that Mahaprabhu was born at very side of the ganges.
Listening from these Mahatmas and by His own spiritual realisation, Sripad Ramdas Babaji concluded that Mahaprabhu's birth-place was at Ramchandrapur on the Ganges at Navadvip. In 1791, Dewan Gangagovinda Roy got a temple of 60 ft height constucted at the birth-place of Mahaprabhunat Navadvip.The temple wasdestroyed by the flood in 1823.
Premananda Bharaji returned to Vrindavan and informed the Mahatmas there about the opinion of Sripad Ramdas Babaji. Sripad Brajamohan Das Babaji was an engineer in previous ashrama. He discovered the remains of the temple establishd by Gangagovinda.That place therefore was decided as the birth place of Mahaprabhu and a temple was built. Now the temple is called ' Sri Sri Gauranga Mahaprabhu Janmasthan Ashram, Prachin Mayapur, Navadvip.
Miyapur and Mollapara were  places dominated mainly by muslims on the opposite (east)side of the ganges. Deputy Magistrate and a devotee Mr. Kedarnath Dutta bought a big plot in Miyapur and being mistaken by the word Mayapur in Bhakti-Ratnakar of Sripad Narahari Das, had built a birth-place temple there, renaming Miyapur which is a muslim word, as Mayapur. The then Vaishnav Mahatmas got very aggrieved and shocked seeing this.(Reference: Vaishnav jagate Sri Radharaman Charandas Babaji Maharaj o Sri Ramdas Babaji Maharaj, Ava Sarkar, Pustak Bipani, page 76-77).

So it seems that the temple at Prachin Mayapur , Navadvip is the authentic birth-place of Mahaprabhu. But other views with logic and evidence are welcome.
UPDATE
According to some researcher, an idol of Vishnu called 'Ashokshaja' has been found buried under the ground at the prsent  Mayapur 'Yogapitha'(Birth-place temple) which is shown as a proof of the original birthplace being there.Regarding this I want to mention the following:
1.Mahaprabhu was so much respected throughout the entire Bengal including Navadvip, that His family deity would be buried underground is highly unlikely. The idol of Mahaprabhu worshipped Sri Mata Vishnupriya and His 'paadukas' that Mahaprabhu gifted Her being worshipped at Navadvip till today. I never got mention of Vishnu idol as His family deity in the authentic biographies like Sri  Chaitanya-Bhagavata and Sri Chaitanya-Charitamrita.

Mahaprabhu's family was originally worshippers of Shakti. This is mentioned in the well -researched biography of Mahaprabhu by Swami Saradeshananda.(Introduction, page 21).This is also proved by the fact that Mahaprabhu before taking sannyasa gifted a copy of 'Sri Sri Chandi'( Devi-Mahatmya) made by Himself to His great grandfather Sri Upendra Mishrawhile visiting Him at the Varaganga village, Srihatta. This is almost impossible for members of a Vaishnava family.The Chandi was regularly worshipped there at the place known as the 'Chaitanya-bari' in Baraganga Sri Hatta until it was stolen some years ago (Reference: Dr.Jayadev Mukhopadhyay's research-work :Knaha gele toma pai, praachi publications, 1st edition, page 89).

It is recorded that Mahaprabhu visited the Shakti temples like Devi Bhagavati (padmakota), Viraja Devi (Yajpur, Odissa), Gauri Devi (Bhuvaneswar), Kamakshi Devi (Kamakotipura), Devi Kanyakumari (Cape Comorin), and the Lingaraj temple (Bhubaneswar) and worshipped these deities with divine ecstacies. If He were from a Vaishnava family, this behaviour would be very highly improbable. (Ibid. page 91-2).


Resizing image to real world dimensions

Question: this may sound like a really amateur question but I'm trying to resize some images to dimensions in centimetres (10cm height x 15cm width to give you an idea), but upon changing two photos to the same centimetre dimensions, I notice they have completely different pixel dimensions? Am I doing it wrong or is this meant to be this way. Thanks
Comment: Are you `Resampling` when you change dimensions?
Comment: Yes, as I can't achieve 10x15cm when I uncheck resample because it automatically changes the sizes based on whatever I put in
Comment: You can print an image at a certain size, and an image can have a certain number of pixels. If your images have different pixel dimensions at the same physical size it simply means that one image contains fewer pixel in the first place.
Comment: Is the resolution the same between the images?
Answer: Simple ratio: PPI = Pixels per inch
Same centimeters with different number of pixels mean different densities of said pixels. The denser the pixels, the highest the quality (resolution). So one of your images might be 72ppi while the other might be 300ppi.
Comment: One image resized to 10x15 turns out like this http://prntscr.com/7yxa08 - the other turns out like this: http://prntscr.com/7yxanl
Comment: I specified 72 PPI on both images when resizing, yet they still have different dimensions in pixels, will they both print 10x15cm ?
Answer: First understand that resolution + width + height = Print size.
You can't change the left side of the equation and expect the right side to stay the same. From the sound of things you are trying to alter the width, height, and resolution but retain the print size. That's why you are struggling.
If you are not printing these images, the resolution field means nothing. See Here
If you are intending to print these images, then you want a minimum of 240PPI in the resolution field and you do not want to Resample when changing the width and height. This often means you get a width and height (print size) which is different than you anticipate.
When you uncheck the Resample option and subsequently alter the Resolution of an image, Photoshop does not generate new pixels (interpolation). It merely changes the density of the existing pixels in the image. This is done to keep the image quality the same. However, in order to do this the width and height must change to match the new pixel density of the image.
You can do what you are trying to do. However, it is not recommended for print-destined images, and you have to do it in 2 stages....

WARNING: This often results in low quality images.

Image > Image Size check Resample and set the Resolution to 240PPI. Then click OK.
Image > Image Size uncheck Resample and input the width and height you want. Then click OK.

This will get you images at the dimensions you want and the resolution you want. However, chances are very high that the images will not look as good as you think they will. Doing this often results in degradation of the image overall.
WARNING: This often results in low quality images.

While I point out the steps above, you should reexamine the images afterward to ensure they still appear suitable for reproduction. These steps are inherently bad to perform on most print-destined images.
Comment: Why the down vote?

Resizing image to real world dimensions


Are decomposition methods applicable on large linear programs?

Question: Working on a very large Linear Program, we tried out some primitive implementations of decomposition techniques such as Lagrangian relaxation and column generation. However, none of these were able to only come close to computation times achieved with the Barrier algorithm.
Thus, we assume that these decomposition approaches only work well on Integer Programs, which is why they are almost solely discussed for IPs in the literature. This would indicate that LPs are "well-solved" with the Simplex algorithms and methods such as Barrier or Interior-point.
Is there any literature that investigates that point or comes to an equivalent solution?
Answer: As a general rule of thumb, I would say that if you have an LP that fits in your memory, then directly applying barrier/simplex is likely to be the best "out-of-the-box" approach.
In my experience, decomposition techniques, such as Lagrangean/Benders/Dantzig-Wolfe decomposition, work best (and outperform barrier/simplex) in the following situations (the list is non-exhaustive):

The original LP is too large to fit in the memory. For instance, you have a large two-stage stochastic LP with a lot of scenarios, or your LP is the master problem in a Dantzig-Wolfe decomposition (which often has exponentially many variables).
In that case, you can't handle the problem without decomposing it.

The problem has a special structure that you know how to exploit. A famous example is the multi-commodity network flow problem, where the textbook decomposition yields one min-cost-flow problem per commodity.
In that case, you can use specialized solvers for the subproblems, which may accelerate the overall method.

I should note here that, if you have a block-structured LP, then you can also apply a barrier or simplex algorithm with specialized, typically distributed, linear algebra. If you want more background, I can refer you to the introduction of this paper (of which I'm a co-author).
Comment: I have no experience with clusters myself, but I wonder whether solving a problem with a decomposable structure on a cluster is faster using decomposition (farming out each subproblem to cluster node) than not (in which case, as I understand it, chunks of the full problem matrix get farmed out to nodes)?
Comment: I have not seen a computational comparison of decomposition vs block-structured IPMs for large-scale problems on distributed-memory machines (aka clusters). I would expect the latter to be potentially better, but harder to implement. For more background reference: https://opus4.kobv.de/opus4-zib/files/7432/ip4energy3.pdf


Fire Protection of Plywood

Question: I need to build a small door between my garage and my attic. The rest of the wall is plaster on button board and is about the equivalent of 5/8" sheetrock. If I doubled up two sheets of 3/4" plywood, would it offer the same or better fire protection?
Comment: Note that this question might get better answers (or at least differenr answers, with code citations) on the Home Improvement area (misnamed http://diy.stackexchange.com)
Comment: This was an interesting read on the subject: http://www.homeinspectionservices.org/inspection-blog/are-all-solid-core-doors-fire-doors
Comment: This reads like more of a DIY.SE question since just wood, engineered or not, should not be considered fire protection. That and you are just really asking about making a fire protected door..
Comment: Well you could add a layer of PEEK (polyether-etherketon) on top of the plywood... low thermal transmission, ignition temp of around 600°C which is about twice the ignition temp of wood, and self-extinguishing. That'll greatly improve the overall resistance to fire.
Answer: To lead from a comment you made on another answer

In a hospital I used to work in, the fire doors were made out of wood and were rated at 1.5 or 2 hours of protection as a function of their thickness.

I think I get it now. The doors you speak of do not stop fire dead. It's not about fire protection but more about giving time for people to be able to leave the premises. Fire beats wood. That is a fact. It does however take time. A basic definition from a Quora post:

Fire Door specifications
Fire doors are not just the door itself, it includes the frame, ironmongery, glazing and smoke seal.

Point to take from that is just having wood alone does not constitute fire protection. There is a reason that these types of things have complete codes to define their production, testing, use and safety thresholds.
2 sheets of plywood alone I do not think are good fire protection by any means. The thickness of the wood is not the sole reason it suffices in other fire doors.
Comment: When I checked at a local lumber yard, they had fire resistance treated plywood. I would only need about half the sheet to make up the door. I was hoping conventional plywood would suffice and I could use the rest of the sheet for something else. Regardless of what I do for the door, there are air gaps in the skip sheathing on the rafters so any fire would easily make its way through them. The house was built in 1949.
Comment: _ Regardless of what I do for the door, there are air gaps in the skip sheathing on the rafters so any fire would easily make its way through them_. That was the point I hope you would make.
Answer: It would be a better idea to screw a sheet of steel to it on both sides.
Comment: Polished (at least not painted) steel reflects heat. The same way that the steel that is on the fire side reflects heat, the one on the other helps the heat stay inside the door. Which leads us to heat conduction; the same steel that helps lead heat away from the door also helps it into the wood in the door. The situation is garage/attic so we can guess the fire is in the garage. A reflective piece of steel on the garage side and none or conductive on the attic side. It is beginning to get complicated... That is why we have drywall. And treated plywood. FWIW
Comment: An important benefit of sheathing is that it keeps air away from the wood, so no flame can develop. If you think steel conducting heat to the wood is significant, consider the effect of a flame on the surface of wood.
Answer:
If I doubled up two sheets of 3/4" plywood, would it offer the same or better fire protection?

Unless it's plywood treated with flame-retardant, no.  Regular plywood has basically zero fire rating.  Type X 5/8" gypsum drywall has a 1-hour fire rating.
Why would you want to build a fire barrier out of something flammable?
Comment: In a hospital I used to work in, the fire doors were made out of wood and were rated at 1.5 or 2 hours of protection as a function of their thickness. I used a couple of the discarded doors to make a workbench top. I far as I could tell they were just untreated wood.
Comment: they are solid core with a veneer face. The core looks just like normal wood. It's possible it was treated if the treatment doesn't give off and odor or discolors the wood. The two hour door is 1 13/16's inch thick.
Comment: @curt, are they solid wood?  I thought fire doors usually had some sort of fire-retardant fill.
Comment: There is a basic misunderstanding regarding fire protection in this answer and comments.  Matt hit it on the head in his answer.  Fire protection is not intended to stop a fire forever, just long enough for evacuation.  Drywall, plaster and even steel will not stop a good fire, but all will slow it down, including wood.  Some fire rated doors will be solid wood, others may have other fillers.
Comment: All construction assemblies requiring a fire rating by code are tested in laboratories and rated according to test results.  A 2-hour door will stop a fire for at least that long.  Incidentally. the drywall on wood joists  would be rated about 20-30 minutes provided the drywall is fire rated.

Fire Protection of Plywood


How to "saturate" one's voice using sound engineering effects?

Question: I'm studying guitar and I'm trying to sing in the meantime I'm playing.
I was wondering how to saturate one's voice such as in Alizee's song at 2:27

"Le flower power
Est mort de sa belle mort..."
Comment: That's some kind of engineered effect, and not (only) a live-performance vocal technique that the singer is applying by herself.  Are you asking how to achieve the same engineered effect, i.e. what sort of sound engineering tools to use?
Comment: Yes, exactly. What is the material used?
Comment: Title edited to reflect your clarification.
Answer: This kind of effect emulates the behaviour of old fashioned high impedance dynamic microphones and low fidelity amplifiers/speakers; the Shure green bullet is the most well known contemporary model of this type of microphone.  Most guitar amps, public address systems like you find at bus terminal, or even the speakers at a drive through are day to day examples of the kinds of speaker systems involved.  These have limited dynamic range and thus are easy to overdrive, and have a relatively narrow frequency response, in particular cutting off the highs.  These combine to give the scratchy, distant vibe that characterizes these systems.  See the demonstration at about the 1:00 mark here.  Nowadays, these are often exploited by harmonica players.  So one way to achieve this effect is by actually using such a microphone and/or speaker system, though I suspect that on this recording it was achieved via some effects plugin.
Another related effect is singing through a bullhorn.  To me, the effect in your sample is more subtle than an actual bullhorn.  However, searching for "bullhorn vocal effect" yielded this -- a stompbox that spans a range of distortion/eq effects similar to the recording.
So for an effects plugin I would search for bullhorn and/or harmonica microphone effects that are suitable for your setup, or you could roll your own from other effects:

Apply a combination of a highpass and lowpass filters (i.e. a bandpass filter), cutting off the lows below something like 100 to a few hundred Hz,
and cutting off the highs above a few thousand Hz.  As a starting point, I'd go with very sharp stair-step cutoffs, but the ultimate version is up to taste.
Apply some distortion to the signal, this can be pretty rough, e.g. hard clipping.
(Optional) apply additional compression -- the distortion should provide quite a bit of compression, but the dynamic range of the kinds of systems you are emulating is pretty reduced, so you may find you want more (clean) compression and less distortion.

There are no specific guidelines, these suggestions should be considered as  a starting point.  Ultimately you'll have to make decisions based on the source material, the musical context that the track will sit in, and your own aesthetic judgements.
Comment: Okay, that's very good suggestions! Thank you! And what about a software? Is there any good enough? I understand that it would probably do the job aftewards, except if you have an idea?
Comment: @Marine1 I'm not well versed enough in what is out there to make a suggestion.  Plus, you have not indicated what software setup you are already using, which might affect suggestions you might get from others.  However, note that answers on this site tend to avoid giving specific equipment recommendations (http://meta.music.stackexchange.com/questions/125/are-shopping-list-questions-on-topic?lq=1 ) so you might have better luck with specific suggestions on other fora.
Comment: Another aspect of the "harmonica" sound is that those bullet mics were often plugged into small guitar combo amps by harmonica players, and overdrive and reduced frequency response is also a hallmark of the sound of a small, cranked-up combo.
Comment: @Dave Okay, I understand why you don't specifically give equipment recomendation. At least, it's to understand how does artists do.
Answer: To create the sound you refer to, the signal must be altered by applying an engineering effect. The use of digital processing has made these type effects easy to achieved using relatively inexpensive equipment. The effect can be applied at the time the input is received (such as in a live performance) or in post production when a recording is made in the studio.
If you want to accomplish this on your own - singing while playing guitar, you can use a vocal effects processor like this TC Helicon Voice Live Play. I show this one as an example of the type I refer to and this is not intended to be a recommendation.  There are many other similar processors that work well.
Many vocal processors include multiple presets and the ability to create your own user defined presets that can be created by modifying the parameters of an existing preset and saving it as a custom preset.
I have one that has a 60's radio effect preset that comes pretty close to the sound you describe.  I have another that has a megaphone effect that also achieves the sound you are looking for.
Most home studio recording equipment and VST software will include some preset's or patches or mastering effects that will give you that sound.  My multi track recorder has a megaphone mastering effect that can be monitored during recording or added after the vocal is recorded.  Application of this effect can occur during recording or applied during mixing and mastering (post production).
This "effect" is probably achieved through band limiting and compression and boosting the output gain of certain frequencies and adjusting the dynamics.   But since there are so many devices available that have the presets or patches built in, you don't need to be a recording engineer or sound engineer to achieve your desired result.
Have fun experimenting.
Answer: The two main components of this effect are EQ and slight overdrive/distortion.
With the EQ cut out the low and the high frequencies leaving only the mid frequencies. Essentially you will end up with a narrow band of frequencies in the middle that give kind of an "old radio" sound. You can do this with any EQ that has an adjustable high-pass (allowing only the high frequencies through which cuts off the low end) and an adjustable low-pass (allowing only the low frequencies through which cuts off the high end). You might be able to get a decent result with a graphic EQ, but you won't have as much control over fine tuning it. You will have to experiment with the cut-off frequencies to get the exact sound you want, but just doing this EQ move alone with get you very close to the sound you want.
Then add a slight amount of overdrive to give it some "edge" and "grit". You still want the lyrics to be understandable so don't over distort it. Any overdrive or distortion effect should work here as long as it sounds decent when you only add a little bit of overdrive/distortion.
Optionally, you could also add some additional compression (overdrive/distortion already has a compressing effect to it) to even out the sound more by bringing the loud parts down in volume and this also produces a "fatter" tone as well.
Answer: That's not really "saturation". Saturation happens when you run things through a tube amplifier and get harmonic distortion. Here's a good article on that: http://www.soundonsound.com/sos/feb10/articles/analoguewarmth.htm
What this is is simply a megaphone/telephone effect with some distortion thrown in. The other answers have good ideas on how to achieve this, with the gist being a high pass and low pass to cut out both the lows and highs of the human voice, in effect simulating a telephone. In fact, the voice frequency is defined as between 300 Hz and 3400 Hz. But I figured I'd just let you know what "saturation" typically means in the audio engineering world. :)


How would PCA help preserve privacy?

Question: For example, if we have a recommender system based on some data like MovieLens, where we have a matrix of user / movie pairings, how would reducing the dimensionality of the dataset help with privacy?
Answer: If I understand it correctly, PCA can be explained as creating new dimensions which are combinations of the existing dimensions but which are more efficient at describing/summarizing the data without being redundant. See this question for an excellent explanation.
That being said, the new contrived characteristics may depend on the original ones which are privacy related, but the original identifying characteristics are obfuscated by being combined/convoluted with other independent variables to create the new dimensions.

How would PCA help preserve privacy?


I have a pulse oximeter. Can I use the O2 readings to improve my workout?

Question: My pulse oximeter displays both the heart rate and O2 saturation. Heart rate readings are useful enough. But what about O2 saturation? I'm thinking of cycling in particular, but I assume any benefits would translate easily to any kind of physical exercise.
Comment: What workout are you asking about?
Comment: Does your oximeter only display saturation?  Typically basic metabolic equations use oxygen consumption more than saturation.  I'll try to find out how saturation can be used for improving performance.
Comment: Yes, just saturation. (It's this one: http://amzn.to/1eAC4Zz). The description reads that O2 saturation is "a key measurement that enthusiasts can keep track of during training...."
Comment: @whitman Just don't kill yourself trying to read numbers from this device on your finger while cycling fast.
Answer: O2 Saturation can, for the most part, be ignored.
If your O2 Saturation levels are low, then your lungs are not getting enough oxygen to your blood.

Are you not breathing very much? You have to breath more when you exercise.
Did you just complete a very hard exercise (like cycle to the top of a very large hill)? Your blood may have just used up a lot of oxygen doing that strenuous workout. Take a few moments to let your body recover by not exercising while your lungs send fresh oxygen through your body.
Are you cycling in a confined area? If you are working out of your garage (stationary bicycle) and the car is running, that is not good! There may not be enough oxygen to keep you alive, and your O2 levels are definitely going to be dropping, because you are dying! Open the garage door, turn the car off, and step outside to get some fresh air.

That said, if you notice your Oxygen Saturation Levels dropping during a workout, you should seriously consider sitting down a moment to let your body recover or step outside to get some fresh air.
There could be people with medical conditions that need to monitor their blood's Oxygen levels, but for the most part this is not anything you are going to control on your own.
Answer: Blood oxygen saturation will go down slowly as exercise intensity goes up, then probably drop quickly to around or below 90% when you exceed maximum O2 intake (i.e. you can't breath any harder). At low spO2 values you will rapidly reach exhaustion. You can find articles on the subject on Livestrong or 3fatchicks.
The problem with LED-based oximeters is that they tend to not deal very well with motion artefacts. So during exercise you may end up with bad readings, held-up values or no value at all.
Heart rate tends to be easier to use as a physiological parameter when monitoring effort level.
Answer: Pulse Oximeters rely on arterial pulse flow at the capillary bed being sampled--typically your index finger. Accurate readings rely on how well your oximeter detects a pulse. I stopped using mine when hiking and biking because excessive movement, high ambient light outdoors on the probe area, and less flow at my finger tip (because more blood was being pumped to my legs?) made it difficult for the probe in my oximeter to detect a signal and thus ill-defined waveforms and readings I could not rely on.


Should I send an email correcting my spelling mistake in a job application?

Question: Applying for a journalism internship I really want and of course in the last line of the email I wrote "your welcome to call" instead of "you're welcome to call". Should I acknowledge this mistake or leave it and hope it doesn't matter? Of course the context of this industry makes me think it's more important.
Comment: Offtopic: I was told by my English teacher that contractions like `you're` are to be avoided in written formal English and that the full form `you are` should be used. Contractions seem to be ok in informal texts, though.
Comment: *"... I really want and of course in the last line of the email ..."* If this is any indication, a small typo is not the real problem.
Answer: You screwed up.  Don't make is worse by pointing it out by misguidedly trying to "fix" it.
Think about what they know and what pointing out the mistake will tell them.  Maybe they didn't notice.  If they did notice, most likely they realize it's a small typo.  Assuming the rest of the resume is well written, at worst that just says "sloppy".  Do you really believe that they think you don't know the difference between "your" and "you're"?
You're guilty of letting a mistake slip thru, not of making one in the first place.  Therefore, pointing out the mistake won't do anything useful.  You still didn't catch it when you should have, and catching it after it's too late doesn't really mean anything.  On the other hand, it makes you look like a weenie.
Fix the resume now.  If you see them again, bring the updated copy and give it to them without any fanfare.  If they ask what you changed, just say you fixed a typo and some minor wording (it would be good to fix something else too).
Added
David K pointed out that this slip-up was just in a email, not on your resume as I was somehow assuming.
Seriously!?  Forget about it!
While they may well expect that you carefully proofread your resume, or any written example copy you may have submitted to them, they're not going to hold you to the same standard for a one-time email.  Whoever read your email message has most certainly made a few mistakes in emails of their own.
This is a non-issue.  Trying to "fix" this will seriously make you look like a weenie.
Answer: If it was a typo on important information e.g. on contact info or names, a follow-up email with a correction would be appropriate. But for a common misspelling like this I would be more annoyed by a follow-up email on the typo than the typo itself.


Vibrato practices on Violin

Question: While practicing vibrato (I've just started) I noticed that while vibrating, for example, on the D string with my third finger using the wrist, when I pull back and forth the third finger, while pulling back, it  sleeps on the A string. I tried to vibrate where my third finger moves in such a way that it doesn't lean on to the other string when it's downwards but it doesn't seem to help. So I wanted to ask that is it normal for the vibrating finger to do that?
Comment: Pulling? It's a rolling action, longitudinally along the string.
Answer: Short answer: Probably not.
Long answer:
No, that's not normal (unless your fingers are very wide or something). For now it's probably not causing you issues, but when you one day need to vibrato a double stop, this will become an issue.
Your problem is most likely caused because your wrist is not straight. In your case, it sounds like you have what my teacher used to call "pizza hand" or the "waiter/waitress"-- make sure your wrist is not touching the neck of your violin, because this will mess up both the sound you produce, and more importantly the angle that your fingers approach the fingerboard at.
If you have your wrist ruler-straight, you shouldn't have this problem with your vibrato. (Although it's hard to say things definitively without seeing your motion, "pizza hand" will definitely cause many issues if you have this issue.)
Answer:
is it normal for the vibrating finger to do that?

It is never normal to do that regardless of whether you are vibrating or not. You will have to learn to stop doing this when you come to play double stops on none-open strings because if one of your fingers touches the adjacent double-stopped string you get a horrible sound.
When you vibrate you do not move your finger from side-to-side. You try and move it as much as possible in the line of the string.
The only time one finger should touch two strings at the same time is when you are playing a fifth where the same finger is deliberately holding down two strings at the same time.
Comment: I have to disagree a bit. I'm not sure anyone's fingers are so slender that they can place them on a string in first position and not lightly contact either the string above or below. When I need to play a double stop with the higher string being open, I simply place my finger more to the "left" than usual. That said, @Ruchi, it's impossible to know whether your motion is normal or not without seeing it.

Vibrato practices on Violin


First use of the slang term "Scrub"?

Question: The slang term "scrub", when referred to a person, can mean several things. It seems like the original usage as an adjective is someone who is not good at something - video games, sports, etc. I am interested to know if the first time it was used to refer to a "guy who thinks he's cool but he's not" was in the TLC song "No Scrubs". I am not familiar with the term before that and it seems like an isolated usage.
Comment: i think a good rule of thumb is that if you heard a strange word or usage in a modern song, chances are the song did *not* originate it.
Comment: Not really an answer, but I've been reading a lot of Patrick O'Brian's Aubrey/Maturin series lately (written ca 1970, set ca 1800) and *scrub* is used frequently to mean "a dishonorable man".  This is historical fiction, but O'Brian's writing is extensively researched and he is very keen on accuracy, so I would expect this is backed by contemporary evidence (but I don't know for sure).
Comment: Hmm yeah I think "a dishonorable man" is closer than the etymonline reference discussed below. Maybe someone can dig up an authoritative reference.
Comment: A scrub refers to a scullion. In the army, the idiots and weaklings are the ones who take care of the dishes. They are the scrubs.
Comment: I don't know about the first usage, but "No Scrubs" was not an isolated usage. At least in Maryland in the 90s, "scrub" was a middle-school playground insult for someone who was poor, unfashionable, unhygienic, and/or socially inept. Think of "scrubbing a rocket launch" – a "scrub" is someone who never made it off the launch pad.
Comment: "No Scrubs" is not the first usage of this term in music.  As a counterexample, it was used in 1989 by De La Soul  in the song "Can U Keep A Secret."
Answer: I vividly remember the term scrubs being used in the late 1960s in high-school sports (in Texas) to refer to the players who barely made the team and would be extremely unlikely ever to appear in an actual game that wasn't already a blow-out win or loss. Often scrubs were underclassmen who were included on the team to get seasoning and on the off-chance that they might develop into useful players in future years when some of the current players would have graduated.
Robert Chapman & Barbara Kipfer, Dictionary of American Slang, third edition (1995), has this entry for the noun scrub:

scrub 1 n by 1589 A contemptible person =BUM [example omitted] 2 n by 1892 An athlete who is not on the first or varsity team; a lowly substitute {ultimately fr. scrub, "shrub, a low, stunted tree"; the quoted 1990s teenager use is an interesting survival or perhaps a revival based on the second sense}

J.S. Farmer & W.E. Henley, Slang & Its Analogues (1903) lists these known meanings of the word:

SCRUB subs. (old colloquial).—Any mean, or ill-conditioned person, or thing ; as adj. = paltry, mean ; also SCRUBBED, and SCRUBBY ; SCRUB-RACE = a contest between contemptible animals ; after FARQUHAR and The Beaux' Strategem (1707). —B. E., GROSE. [Examples omitted.] 2. (American Univ.).—A servant.

As late as Chapman & Kipfer, Dictionary of American Slang, fourth edition (2007), there is no suggestion that a scrub "thinks he's cool but he's not." Indeed, Tom Dalzell, Flappers 2 Rappers: American Youth Slang (1996) gives a decade-by-decade account of why any pretension to coolness is exceedingly unscrublike:

[College slang circa 1900:] scrub A second-rate person
[Youth slang of the 1930s:] scrub 1. A poor student 2. A member of the second team
[The 1970s and 1980s:] scrub A younger person, perhaps a freshman
[Hiphop era (1980s and beyond):] scrub Someone with no talent.

I can imagine someone who thinks he or she is cool—and who perhaps really is cool—denigrating someone else who allegedly thinks he or she is cool, by calling that person a scrub; but arguing that a scrub is fundamentally someone who thinks he or she is cool but actually isn't makes no more sense than saying that a square is fundamentally someone who thinks he or she is a trendsetter but actually isn't. In both cases the assertion goes against generations of contrary usage. In the case of scrub, the essence of the insult relates to the scrub's irrelevance and talentlessness, not to the person's false sense of coolness.
Comment: You are being pedantic here. "A guy who thinks he's fly and is also known as a busta" is just part of an extended example given by TLC, not a definition. The example continues, "...always talkin' 'bout what he wants and just sits on his broke ass." They are speaking of the qualities of this particular scrub. It is also arguable from the rest of song that TLC's use of the word is closer to "a contemptible person."
Answer: Etymonline.con has this to say about scrub. see scrub(n.1)
The second paragraph seems to say the way TLC used it (which I believe means a man without wealth) was first documented in 1709, slightly before the popular R&B hip-hip combo became successful.
Etymonline doesn't have a reference for scrubber, that would be nice to know as well
Comment: @cduston I suspect _serious_ regarding the lyrical choices of TLC is stretching a point. TLC may well include a sense of _false representation_ but I think their basic point is _If you got no money, you won't get this honey_ as shown by the lyrics _...broke ass_ and _If you don't have a car and you're walking_ and _If you live at home wit' your momma_ which are clear indicators of a lack of 'G' (referenced by Ms L.E.Lopez in her Rap-solo) and compounded by the rather blunt _Wanna get with me with no money, Oh no I don't want no (oh)_
Comment: I know we are not supposed to add comments of the form "gee great comment" but seriously - utilizing an air of scholarship around TLC lyrics makes your comment priceless, and convinces me of your answer. Well done!
Comment: @cduston An _air_ of scholarship ! Nothing to do with my M.A. in _TLC lyrics; the meanings and the wider applicability to the empowerment of young women in the last decade of the 20th century_? ;)
Comment: Well this is a nice answer, but I'm not sure I agree with your interpretation of that second sentence having the right meaning. Excerpt from the song: "A scrub is a guy who thinks he's fly, and is also known as a buster. Always talkin' about what wants, and just sits on his broke ass". Maybe we can't get too serious here, but I think the meaning includes some kind of false presentation, and not just a man without wealth (which your etymonline reference clearly includes).
Answer: The Oxford English Dictionary has a few relevant definitions:

"A mean insignificant fellow", dated to 1589
"A hard-worked servant", dated to 1707
"A player belonging to a weaker team", dated to 1892
Answer: It comes from the Nintendo 64 game "The Legend of Zelda: Majora's Mask", where somebody begins the game as a Deku Scrub, after being turned into one very early in the story. Players who were not able to reach a point where they would return to their human form would be a) terrible at the game and b) scrubs forever.
Comment: Sorry, the song (1999) predates your video game (2000).

First use of the slang term "Scrub"?


can we use custom service application for FAST in sharepoint 2010 for content to publish?

Question: I have a scenario where i need to crete custom sharepoint service application and need to use FQL for getting the content from FAST and send the data to various farms or users through Email or someother process .Will it be possible to use custom sharepoint service application for FAST to get the content?
Answer: I really doubt that that is your scenarion. What you describe, is a solution for a specific problem and you are not sure that it is going to work. So my question for you:
what is your problem?
Do you need to get always the same content? Or is it a static query that is always the same? Will you need to expose content to other applications than sharepoint in the future? What about seciurity trimming?
your first start will be to consume the web service that is tied to your site collection, to query your data by fql.
A custom service application is always possible, but I really doubt the need for it. Aside from that: custom service applications are a bit complex and do cost a lot of work, as you also need to implment UI, authorization etc. for it. maybe a small,reusable library will be sufficient for you.
Comment: I need to implement service application a 24x7 timer job associated to it so that the conetnt is placed to various regions but in the same time (7am in usa should be the same 7am in india).But my query is is that possible to grab the data from the fast using fql by service application.It is not a static query and need to expose content to others too.Please help me out with it.Thanks for your reply.
Comment: Thanks Bas Lijten for your reply.I will elaborate our scenario .Actually we have content coming from different lists but we have fast search in the middle and service application at the end .So the custom service application will be getting the data from the fast indexing and its hould be automated(custom service application) using timerjob which should run 24X7
So how can i start with actually i have created a service aplication but how to implement timer job to make it automated an drun 24X7?Please need suggestions.Thanks .


Cold water intake corroded on hot water heater

Question: Our hot water heater is just over a year old. I am sure it is under warranty, but I'd like to get ideas why this happened. It is currently dry, but you tell water was leaking. We didn't notice this because the heater is behind a screwed in piece of drywall.
We are on a well.
Comment: It looks like a leak at the connection. It could be water condensing on the pipe if this is in a humid room.
Comment: I have had some very slow leaks (which I would call *seeps*) seal with time. This has occurred both with threaded connections and sweated joints. When seeps with threaded connections sealed I had used pipe dope not teflon tape. AFIK when there is a leak in a threaded connection sealed with teflon tape it continues indefinitely. The relevancy here is that your threaded joints might have sealed. I would not redo them until you verify that they are still leaking.
Answer: That kind of corrosion on a one-year-old tank? WOW. Like Ed Beal noted, it looks like a leak at the connection. The installer likely did a poor job of taping the connection (with teflon tape) or failed to tighten it adequately.
However, the excessive rust is curious...I suspect that your well water is rather salty. When salty water evaporates from a surface, it leaves behind salts which contribute to rusting on metal surfaces by attracting moisture from humid air. It doesn't take a lot of salt to do this. Just the thinnest film is enough to constantly keep it somewhat wet enough such that underlying metal can be constantly corroded. I suggest tightening the union, scraping off the rust, and painting over with a water-based sealing compound. And take that sheetrock cover off!
Comment: Well (no pun intended), we live near the ocean so it could very well be salty. This is one of many issues we are dealing with in our new house.
Comment: Your local water resources board may have groundwater quality maps that detail the encroachment of saltwater into community groundwater supplies over time. This happens when there is excessive groundwater demand and insufficient fresh water recharge. Getting your water tested will also help you figure out what treatment options are best. Good luck!


Creating a duplicate label in QGIS 3.4

Question: In QGIS 3.4 I'm creating a set of ten maps (layouts) from one QGIS project, and each map centres over a particular polygon. In each layout I shift the map to centre it on the page or to fit as best as possible. From that polygon layer I create labels, and I then get one label for each polygon. I can use the tools to manipulate these labels as required, as the labels need to be moved a bit here and there.
  Is it possible to select a label and duplicate that label and have the duplicate locked in the map to another place? This is so I can move the duplicate to the best place for individual map, keeping the original where it was for the previous map. What I can do in ArcGIS: create an annotation layer from labels and then have full control of over that text (copy, resize etc) and have the text locked to the map where I want it - Well I would like to do that in QGIS as easily as I can in Arc. Is this possible?
Comment: You can lock the layers and their styles for a map canvas in the composer after aligning everything as you need it.
Comment: Thanks! How about having editing control over label text after it has been generated? On one map I might want to show the label text "Cubbington & Leek Wootton" with "Cubbington &" on one line, and "Leek Wootton" on the 2nd, and in another map "Cubbington" on it's own line etc. Can you select a label and then have control over how that individual label is shown? Would it best just to put the labels in as map elements (such as I do with a title etc) were I know I have control over them - with the exception of having that text locked to the map, which in those cases I really want to do.
Answer: i am not really sure i understand your question, but it seems i had a similar problem: a large qgis project with different print layouts each representing a different print frame of a collection of 4 maps. layouts would overlap for about one inch, and i had to manually move the labels so that they would not be cut by any layout border. i have solved this problem by either moving the label on frame 1 or frame 2 only, and paid attention not to cut the labels placed in the overlapping strip, by moving them at the center of the strip so that they could be fully legible in both layouts. a different, less elegant solution would be to place the majority of labels, then duplicate the label layer and personalize them for each layout. you would end up with labels layer 1 on when you are working on layout 1, a similar but not identical label layer 2 when working on layout 2 and so on... keep in mind that you have the option to save the label placement info within the qgis project or in the layer file (old style method by adding additional columns for x and y position), you will probably need the latter in this case.
Comment: Thanks. How do I duplicate the lable layer?
Comment: right click on the layer > duplicate layer

Creating a duplicate label in QGIS 3.4


I cannot add more Categories to my menu

Question: I am using the theme Hemingway Rewritten. I added 8 categories by adding "uncategorized" and then changing the navigation label. But at the bottom the original still says "uncategorized" so my posts aren't going to the navigation label, the way I want them to. It let me add 3 actual categorize like "puppy mama" and then the original also says "puppy mama" so the post went to the correct spot. Not sure what to do. Thanks
Answer: Changing the Category label doesn't change where the menu item goes, you need to actually add the category. You can't add a menu item for uncategorized and change it to an actual category.
Comment: How do I add a category then?  When i'm customizing my menu, they all say category next to them just like pages say pages and the posts say post.
Comment: On the Menus screen, on the left, there's a list of types of things you can add to menus. One of them is Categories. Click that to expand it. Inside you'll see a list of Most Used categories. Check the boxes next to the ones you want to add and click Add to Menu. You can use the tabs above the list to also view All categories, or search for specific ones to add.
Comment: the only way I can add to my menus is if on the front page  I go click on the customize next to themes and them click menus and then from that point, there is an add items button at the bottom. So i click on that and go to categories, but it won't let me add anymore, it just shows the 3 I already have plus an uncategorized option.  Is there another menu screen i'm missing?
Answer: I received an answer for the questions on a different site. You have to have a post (also adding the category and tag within the post) before it will let you create the category page on the menu.

I cannot add more Categories to my menu


how to solve $ {\partial u \over \partial t} - k {\partial ^2 u \over \partial x^2} =0$

Question: How do I solve the following PDE for it's general solution?
$$ {\partial u \over \partial t} - k {\partial ^2 u \over \partial x^2} =0$$
How do I determine the general the solution of this equation will be $u(x, t) = X(x)T(t) $? I tried Monge's method but couldn't get it. My textbook only deals with particular solution using boundary condition.
Comment: @doraemonpaul: Let $s=kt$ to get rid of $k$.
Comment: It's a heat equation. On Wikipedia you can find a review of some solution techniques. http://en.wikipedia.org/wiki/Heat_equation
Comment: @Siminore doesn't this assume that the general solution of this equation will be of [this form](http://en.wikipedia.org/wiki/Heat_equation#Solving_the_heat_equation_using_Fourier_series)
Comment: I am particularly looking for it's general solution analytically. I tried few steps and got stuck after that.
Comment: I don't understand your question. You determine the solution will be of that form by assuming it will be and finding out that you get something that works. Once you know it works you can you existence and uniqueness results to see that you got something general enough to get all of them.
Comment: @Matt is it pure guessing?
Comment: Yes, but this is how most differential equations classes go. You make an educated guess and see if it works. In this case, you guess that you can break the solution into a product of a function of one variable $x$ and another function of one variable $t$.
Comment: I'll try that ... and see what happens
Comment: It is easy to write down an equation, but it may be difficult to write down a solution. You first want to define a solution, and then try to construct such a solution. In PDE theory, the definition of solution depends on the context, since it is really hard to find the most general solution of a given equation.
Comment: @MonkeyD.Luffy: See [here](http://en.wikipedia.org/wiki/Partial_differential_equation).
Comment: $Hans Lundmark: my answer has been already reach your effect.
Answer: I am not sure that my answer is an answer to the question. I assume that the OP would like to understand why the general solution of the heat equation is the one we all study in PDE courses, which is found by separation of variables. This question is far from trivial: we are given an equation and we conjecture that its solution(s) can be written as a product of two functions of two independent variables. Why?
 Well, the answer is never given in first courses on PDEs. And the answer is that there is no reason why this should be really true. As Evans writes in his book on Partial Differential Equations, it is useful to find particular solutions, for example the so-called fundamental solution. But there is no reason why this should be the most general solution of the given equation.
 For the heat equation, there is no universal uniqueness theorem. Evans shows that uniqueness holds among solutions that grow at most like $e^{x^2}$, but he refers to another book for the construction of infinitely many solutions of the heat equation that grow even faster than $e^{x^2}$.
In my opinion, the expression "general solution" should be carefully avoided, when studying PDEs. Only for a very small number of equations does a complete classification of solutions exist. A lot of things depend on boundary conditions: an equation may have infinitely many solution if a Neumann boundary condition is prescribed, and only a constant solution if a Dirichlet condition is prescribed.
Comment: My "answer" does not criticize the use of separation of variables at all. I know that it is useful to construct explicit solutions to PDEs. The point is that in general we are not sure that *the* solution we are constructing is the *general* solution, as the OP was asking. I mean: it is a solution that was found by some *ansatz*, and only a uniqueness theorem can state that our ansatz was the only admissible ansatz. Unluckily, this kind of uniqueness theorems may not exist at all.
Comment: See [here](http://en.wikipedia.org/wiki/Partial_differential_equation).
Comment: I don't really agree with your answer, as even solving any PDEs by using separation of variables, it is the best to find their general solutions first, see the advanced example http://math.stackexchange.com/questions/121202.
Answer: Case $1$: $\text{Re}(kt)\geq0$
Let $u(x,t)=X(x)T(t)$ ,
Then $X(x)T'(t)-kX''(x)T(t)=0$
$X(x)T'(t)=kX''(x)T(t)$
$\dfrac{T'(t)}{kT(t)}=\dfrac{X''(x)}{X(x)}=-(f(s))^2$
$\begin{cases}\dfrac{T'(t)}{T(t)}=-k(f(s))^2\\X''(x)+(f(s))^2X(x)=0\end{cases}$
$\begin{cases}T(t)=c_3(s)e^{-kt(f(s))^2}\\X(x)=\begin{cases}c_1(s)\sin(xf(s))+c_2(s)\cos(xf(s))&\text{when}~f(s)\neq0\\c_1x+c_2&\text{when}~f(s)=0\end{cases}\end{cases}$
$\therefore u(x,t)=C_1x+C_2+\int_sC_3(s)e^{-kt(f(s))^2}\sin(xf(s))~ds+\int_sC_4(s)e^{-kt(f(s))^2}\cos(xf(s))~ds$ or $C_1x+C_2+\sum_sC_3(s)e^{-kt(f(s))^2}\sin(xf(s))+\sum_sC_4(s)e^{-kt(f(s))^2}\cos(xf(s))$
Case $2$: $\text{Re}(kt)\leq0$
Let $u(x,t)=X(x)T(t)$ ,
Then $X(x)T'(t)-kX''(x)T(t)=0$
$X(x)T'(t)=kX''(x)T(t)$
$\dfrac{T'(t)}{kT(t)}=\dfrac{X''(x)}{X(x)}=(f(s))^2$
$\begin{cases}\dfrac{T'(t)}{T(t)}=k(f(s))^2\\X''(x)-(f(s))^2X(x)=0\end{cases}$
$\begin{cases}T(t)=c_3(s)e^{kt(f(s))^2}\\X(x)=\begin{cases}c_1(s)\sinh(xf(s))+c_2(s)\cosh(xf(s))&\text{when}~f(s)\neq0\\c_1x+c_2&\text{when}~f(s)=0\end{cases}\end{cases}$
$\therefore u(x,t)=C_1x+C_2+\int_sC_3(s)e^{kt(f(s))^2}\sinh(xf(s))~ds+\int_sC_4(s)e^{kt(f(s))^2}\cosh(xf(s))~ds$ or $C_1x+C_2+\sum_sC_3(s)e^{kt(f(s))^2}\sinh(xf(s))+\sum_sC_4(s)e^{kt(f(s))^2}\cosh(xf(s))$
Hence $u(x,t)=\begin{cases}C_1x+C_2+\int_sC_3(s)e^{-kt(f(s))^2}\sin(xf(s))~ds+\int_sC_4(s)e^{-kt(f(s))^2}\cos(xf(s))~ds&\text{when}~\text{Re}(kt)\geq0\\C_1x+C_2+\int_sC_3(s)e^{kt(f(s))^2}\sinh(xf(s))~ds+\int_sC_4(s)e^{kt(f(s))^2}\cosh(xf(s))~ds&\text{when}~\text{Re}(kt)\leq0\end{cases}$ or $\begin{cases}C_1x+C_2+\sum_sC_3(s)e^{-kt(f(s))^2}\sin(xf(s))+\sum_sC_4(s)e^{-kt(f(s))^2}\cos(xf(s))&\text{when}~\text{Re}(kt)\geq0\\C_1x+C_2+\sum_sC_3(s)e^{kt(f(s))^2}\sinh(xf(s))+\sum_sC_4(s)e^{kt(f(s))^2}\cosh(xf(s))&\text{when}~\text{Re}(kt)\leq0\end{cases}$
This is already the general solution of $\dfrac{\partial u}{\partial t}-k\dfrac{\partial^2u}{\partial x^2}=0$ . Note that when without any I.C.s, the form of $f(s)$ can choose arbitrary, but when I.C.s are given, the form of $f(s)$ and the choice whether using the integration kernel or using the summation kernel should choose wisely in order to accommodate the I.C.s to get the most nice form of the solution, especially the number of I.C.s is more than two.
Another brilliant method is called the power series method.
Similar to PDE - solution with power series:
Let $u(x,t)=\sum\limits_{n=0}^\infty\dfrac{(x-a)^n}{n!}\dfrac{\partial^nu(a,t)}{\partial x^n}$ ,
Then $u(x,t)=\sum\limits_{n=0}^\infty\dfrac{(x-a)^{2n}}{(2n)!}\dfrac{\partial^{2n}u(a,t)}{\partial x^{2n}}+\sum\limits_{n=0}^\infty\dfrac{(x-a)^{2n+1}}{(2n+1)!}\dfrac{\partial^{2n+1}u(a,t)}{\partial x^{2n+1}}=\sum\limits_{n=0}^\infty\dfrac{(x-a)^{2n}}{k^n(2n)!}\dfrac{\partial^nu(a,t)}{\partial t^n}+\sum\limits_{n=0}^\infty\dfrac{(x-a)^{2n+1}}{k^n(2n+1)!}\dfrac{\partial^{n+1}(a,t)}{\partial t^n\partial x}=\sum\limits_{n=0}^\infty\dfrac{f^{(n)}(t)(x-a)^{2n}}{k^n(2n)!}+\sum\limits_{n=0}^\infty\dfrac{g^{(n)}(t)(x-a)^{2n+1}}{k^n(2n+1)!}$
Answer: It is a classical problem. I recommand you to consult a book on advanced engineering mathematics where you can find all the details you need. Lets try to work it out.
$$ \mathrm{PDE}\quad  u_{t}(x,t) = k u_{xx}(x,t) $$
$$ \mathrm{B.C} \quad  u(0,t) = 0 \,, \quad u(L,t)=0 \,.$$
$$ \mathrm{I.C} \quad u(x,0) = f(x)  \,.$$
Denote the above equations by $(S)$
The technique is based on the method of separation of variables. It works as, assume the solution has the form $u(x,t)=X(x)T(t) \,.$ Compute the derivatives
$$ u_t(x,t) = X(x)T'(t)\,, \quad u_{xx}(x,t) = T''(x)T(t)\,, $$
then substitute back in the differential equation to get
$$ X(x)T'(t) = k X''(x)T(t) \Rightarrow \frac{T'(t)}{kT(t)} = \frac{X''(x)}{X(x)} \,.$$
It is clear from the last equation that the left hand side depends only on $t$ and the right hand side depends only on x. This means that the equality holds only if both sides are equal to the same constant. Therefor, we get
$$ \frac{T'(t)}{kT(t)} = \frac{X''(x)}{X(x)}=-\lambda^2 \rightarrow (*) \,.$$
The selection of $ -\lambda^2 $, and not $ \lambda^2 $, in the above equation is the only selection for which non trivial solutions exist. It is clear that $(*)$ gives two distinct ordinary differential equations namely,
$$ T'(t) +k\lambda^2 T(t) = 0 \rightarrow (1)\,,$$
$$  X''(x) + \lambda^2 X(x) = 0  \rightarrow (2) \,. $$
Solving the first ordinary differential equation $(1)$ gives
$$ T'(t) = C {\rm e}^{-k\lambda^2}t \rightarrow (**)  \,, $$
where $C$ is a constant. On the otherhand, the function $ X(x) $ can be found by solving the second order linear ordinary differential equation $(2)$,
$$ X(x)= A \cos(\lambda x) + B \sin( \lambda x ) \rightarrow (***) \,, $$
where $A$ and $B$ are constants. Determining the constants $A$, $B$, and $\lambda$ depend on the homogeneous boundary conditions
$$ u(0,t) = 0 \,,$$
$$ u(L,t)=0 \,.$$
Substituting the above initial conditions in $ u(x,t) = X(x)F(t) $,yields,
$$ X(0)T(t) = 0  \Rightarrow X(0) = 0\,. $$
$$ X(L)T(t) = 0  \Rightarrow X(L) = 0 \,. $$
Using $X(0)=0$ into $(***)$ leads to
$$ A = 0 \implies X(x) = B \sin(\lambda x ) \longrightarrow ($) \,.$$
Substituting the condition $ X(L) = 0 $ into $$ ($) $$  gives
$$ B\sin(\lambda L) = 0 \implies B=0 \quad \mathrm{or}\quad \sin(\lambda L)=0 \,.  $$
Since $B=0$ gives the trivial solution $ u(x,t)=0 $ \,, we have
$$ \sin(\lambda L) = 0 \rightarrow \lambda_nL= n \pi \rightarrow \lambda_n= \frac{n \pi}{L}\,,\quad n=1,2,3,\dots \,.  $$
Since $ n = 0 $ gives the trivial solution. It will be excluded. In view of the infinite number of eigenvalues, we write,
$$ X_n(x) = \sin(\frac{n\pi}{L}x)\,, \quad T_n(t) = {\rm e}^{-k{(\frac{n\pi}{L})}^2\,t } \,. $$
Forgetting about the constants $B$ and $C$, the functions
$$ u(x,t) = X_n(x)T_n(t) = \sin(\frac{n\pi}{L}x)\, {\rm e}^{-k{(\frac{n\pi}{L})}^2\,t } \,, n=1,2,3,\dots $$
are called the fundamental solutions that satisfy the (PDE) and the given boundary conditions.
Recalling the super position principle, a linear combination of the fundamental solutions also satisfies the given equation and the boundary conditions. Hence, we have
$$ u(x,t) = \sum_{n=1}^{\infty} \alpha_n  {\rm e}^{-k{(\frac{n\pi}{L})}^2 t }\sin(\frac{n\pi}{L}x)\, $$
where $\alpha_n$ are constants to be determined. To determine $ \alpha_n $, we appeal to the initial condition $u(x,0)=f(x)$ and substitute in the last equation, we get
$$ u(x,0) = f(x) = \sum_{n=1}^{\infty} \alpha_n \sin(\frac{n\pi}{L}x) \,.$$
Comparing the above equation with the Fourier series of a function, one can see that this series is nothing but the Fourier series of $f(x)$ which implies that
$$ \alpha_n = \frac{2}{L}\int_{0}^{L} f(x) \sin(\frac{n\pi}{L}x)\,dx \,.$$
Since the $\alpha_n$ have been determined, the particular solution $u(x,t)$ follows immediately,
$$ u(x,t) = \sum_{n=1}^{\infty} \left( \frac{2}{L}\int_{0}^{L} f(x) \sin(\frac{n\pi}{L}x)\,dx \right)  {\rm e}^{-k{(\frac{n\pi}{L})}^2 t }\sin(\frac{n\pi}{L}x) \,. $$
Comment: I believe that @MonkeyD.Luffy question is different. He/she's asking why the general solution coincides with that we construct by separation of variables. It is a non-trivial question.
Comment: I studied Monge's method of $Rr+Ss+Tt=V$ where R,S,T,V are function of x,y,z and first order derivatives of z. I was wondering if I could apply it to get the general solution of the problem. I can work out the rest.
Comment: @MonkeyD.Luffy: Monge's method is for non linear second order differential equations. While your PDE is the heat equation which is a linear PDE.


Kibana 5 - plotting a stacked bar plot with a different filter for each color

Question: I'm having a bit of truble trying to get Kibana do a certain bar chart.
In a ridiculous reduction, it looks like this:
My data consists of documents of the following structure:
FULL NAME:  "Michael Jordan"
PROPERTIES: "53Y MALE 198cm"
DEPARTMENT: Parquet

FULL NAME:  "Sasha Digiulian"
PROPERTIES: "24Y FEMALE 157cm"
DEPARTMENT: Rock, Ice

FULL NAME:  "Ueli Steck"
PROPERTIES: "40Y MALE 187cm"
DEPARTMENT: Ice

Eventually, I'd like to display a two-colored bar chart with its X axis the department, and the Y axis being a double bar with one color for the number of males for the department and another color for the number of females.
In this case there will be 3 (double) bars for
[Rock, Ice, Parquet]

with Y axis being
[(0,1), (1,1), (1,0)]

Now, for each one separately it is easy - define a filter as a query on PROPERTIES, then a (unique) count aggrigation on FULL NAME. But then again - filter is for ALL the plot, what can I do to make a different filter for each color?
Alternatively, I can try to define a scripted field, something like
MALE_NAME: doc['PROPERTIES'].value=~"MALE"?doc['FULL NAME'].value?""

and same for female. But now, scripted fields won't word on strings...
Any Ideas are greatly welcomed. Thanks!
Answer: Seems like this issue is still open. But then there's a workaround here using the Split Bar aggregation. Give it a go.


Intermittent instances of duplicate participant rows created - is this a MySQL issue?

Question: CiviCRM 4.4 install that has been running for ~ 2 years now, no update to code - in the past week I have seen 3 instances of duplicated participant rows (same contact_id, same event_id, fee, but register timestamp shows difference of 7 minutes to 1 hour).  The participant_id is different of course. Has anyone seen this or have suggestions how to debug this - MySQL server is hosted so I cannot get logs.
Answer: I have seen similar and it has always been traced to the user submitting the (in our case) membership form twice.
For some reason the final "Your membership has now been created" (or whatever it says) message has not been displayed, so they think it has failed and submit again.  Worse still they may get  "We cannot provide that at this time", which they interpret to mean the transaction has failed when really I thnk it is a timeout message for displaying that final "Done" message.
They should have received a confirmation email, but they have given the wrong adress, or it is caught up in a spam filter or delayed in transmission or ?
Why three times in one week? Perhaps there has been a heavier-than-usual load on the shared server leading to time-outs for that final message.
Comment: Hi JoAnne - I don't know why now (3 x in short succession). I do know though that all 3 received confirmation emails - twice - so I am inclined to think it is a session problem rather than MySQL. I know that the event reg. 'thank you' page is supposed to kill the session at the end, and it is possble that the server load was heavy (it's shared but the client doesn't want to deal w/a VPS..) Thank you for answering!


How do you deal with m..n relationships in a relational database?

Question: Let's look at an example - books. A book can have 1..n authors. An author can have 1..m books. What is a good way to represent all of the authors of a book?
I came up with an idea to create a Books table and an Authors table. The Authors table has a primary AuthorID key the author's name. The Books table has a primary Book ID and metadata about the book (title, publication date, so on). However, there needs to be a way to link the books to authors and authors to books. And this is where the problem is.
Let's say we have three books by Bob. However, on one book, he wrote it as Bob, PhD. Another he wrote as Dr. Bob, and a third he wrote as Dr. Robert. I want to be able to identify the fact that these authors are, in reality, the same person but credited under different names. I also want to distinguish Bob from another Bob who wrote different books.
Now let's also add in another part to an application, a Person table that keeps track of interesting people. And let's say that Bob is an interesting person. I want to not only say that the author of all three books is Bob, but that this interesting Bob is the same Bob as the author Bob.
So what strategies exist for such potentially complicated mapping, while ensuring that the book authors are identified by the name on the cover?
Answer: Add another table called BookAuthors with columns for BookID, AuthorID, and NameUsed.  A NULL value for NameUsed would mean to pull it from the Author's table instead.  This is called an Intersection table.
Comment: Evidently Joel is a 46 seconds faster typer than I am.
Comment: And if I wanted to, I could even use BookID, PersonID, NameUsed and just say that an Author is just a special case of a Person.
Comment: Although that would depend on how I defined "interesting person", as perhaps not every Author would be an interesting person.
Comment: How about when an alias is used for multiple books, e.g., Stephen Bachman == Stephen King.
Comment: Or Richard Bachman, perhaps. :) If I follow this example, you would use the same PersonID for all books, but separate AuthorIDs (one for RB and one for SK). If you're normalizing, the book table would have just AuthorID, and Authors would have PersonID to relate both authors to King.
Answer: You'd need three tables -

Book
Author
BookAuthors

Book would contain book id, book title, and all the other information you need to collect about the book.
Author would contain author ID as well as other information such as First name, last name that you need to collect about any given author.
BookAuthors would be a many-to-many join, containing BookID, AuthorID, and NameUsed. This would allow the book to have either zero or many authors, for an author to have either zero or many books, and for information about that relationship to be captured. You could also, for example, have a column on the BookAuthor table that described the author's relationship to the book ("Edited By", "Fore word by").
Answer: I think you're pretty much there.  You need a Books table, an Authors table, and then a "authors_of_books" table with the primary key of the book, the primary key of the author, and a "cited as" text field showing how that particular author was cited on that book.
Answer: This sounds like a many-to-many relationship, not a 1-to-many.  I think you'll want to use a table between those two that allows you to define 1-to-many on either side of that.  Check this out...
http://www.tekstenuitleg.net/en/articles/database_design_tutorial/8
Answer: Given that Dr. Bob and Dr. Robert and Bob, PhD are all the same person, they would link to the same row in the authors table.
However, I think what you need is a person table that authors links to.  You could also link your interesting person table to it.  That way Author Bob and Author Robert as well as Interesting Bob link to Person Bob.  Hope that makes sense.
Answer: The first thing that comes to mind is to have a link table, perhaps called AuthorOf to link books with their authors.
The columns would be AuthorID, BookID and perhaps CreditAs, so you can differentiate between Dr. Bob and Bob, PhD.  (As well as pen names like Stephen King and Richard Bachman).
And you can still uniquely identify the author.
Answer: It really looks like you are wanting to create a series of custom join tables, that are used to associate items from one entity to another.
I would start at the most granular level, person and say that ANY author must be a person.  I would simplify that process.
Create a person table with person information and a PersonId, put the information in there.
THen create a BookAuthors table, with 3 columns BookId, PersonId, TitledName.  THis way you can use a different name if needed, if not, you can use COALESE or something similar to get the default name if TitledName is null.
Just an idea..
Answer: What you're asking really is not how you deal with 1..n relationships, but n..n relationships (as effectively on author and have many books, and one book can have many authors).
The classic way to handle this is via an intermediate table, so
Author table (authorID, authorDetails)
Book table (bookID, book details)
AuthorBook table (authorID, bookID)
If you're really bothered about changing author names then use a 1..n author details table, so add
AuthorDetails (authorID, itemID, authorDetails)
and remove authorDetails from the author table
Answer: For 1..n relationship (author has many books, author has many aliases):

Put a foreign key author_id in Books pointing at author.
Create a new table, author_aliases, to hold the aliases information.
Put a foreign key alias_id in Books pointing at alias (nullable if author details are defaul).
Put author_id foreign key in author_aliases.

If you wish, you can use intermediary tables to link authors and books, but with a 1..n mapping I don't think this is necessary.
For an n..m relationship (author has many books, book has many authors):
You would have to use an intermediary join table (author_id, alias_id, book_id) instead of foreign keys in the book table. You will want to keep the foreign key from aliases to author (for easy lookup of author aliases without having to go via all their books).
You can argue that in terms of scalability in the future this is a better way to start off as well, even if the initial specification says something is a 1..n relationship. You will find that specifications (or question) as given often are inadequate, so you will want to design in the general manner for when the specifications change or are clarified.
Comment: "How do you deal with 1..n relationships" - the question example is clearly meant to be limited to 1..n relationships - not m:n relationships.
Comment: This wouldn't handle collaborations: up to N authors worked on the same book.
Comment: 1..n refers to the number of authors on a book. I should rephrase the question title. There can indeed be collaborations on books where 1 book has n authors.
Answer: a possible implementation in postgresql, just for the fun of it:
create table books (
  book_id integer primary key,
  title varchar not null
);

create table aliases (
  alias_id integer primary key,
  alias varchar not null
);

create table books_aliases (
  book_id integer references books (book_id),
  alias_id integer references aliases (alias_id),
  primary key (book_id, alias_id)
);

create table authors (
  author_id integer primary key,
  author varchar not null,
  interesting boolean default false
);

create table aliases_authors (
  alias_id integer references aliases (alias_id),
  author_id integer references authors (author_id),
  primary key (alias_id, author_id)
);

create view books_aliases_authors as
  select * from books
    natural join books_aliases
    natural join aliases
    natural join aliases_authors
    natural join authors;

one could use "using" instead of the natural join:
create view books_aliases_authors as
  select *
    from books
    join books_aliases using (book_id)
    join aliases using (alias_id)
    join aliases_authors using (alias_id)
    join authors using (author_id);

or do the complicated thing for mysql compatibility (note that mysql would also need an explicit maximal length for the varchars above):
create view books_aliases_authors as
  select b.book_id, title, l.alias_id, alias, t.author_id, author, interesting
    from books b
    join books_aliases bl on bl.book_id = b.book_id
    join aliases l on bl.alias_id = l.alias_id
    join aliases_authors lt on lt.alias_id = l.alias_id
    join authors t on t.author_id = lt.author_id;

this example doesn't use the "people" table, only an "interesting" flag to authors. please note that nothing changes (structurally), if you rename "authors" to "people"


SessionId login failed

Question: Please correct my understanding
1.The user gives his userName and Password to login to my third party application.
2.A access_token is generated for the login.
3.My app should use this accesss_token as sessionId to communicate to the salesforce server on behalf of my user
Is this understanding correct?
If yes then then this sessionId should be valid for eternity unless there is some action(change or something ) from the user.
Then why am I getting a expired sessionId  error?I genereated this sessionId couple of days back.
Answer: You will be following the Web Server Authentication Flow:
https://help.salesforce.com/HTViewHelpDoc?id=remoteaccess_oauth_web_server_flow.htm
A salesforce sessionid is different than an access_token, and hence their also is a refresh_token that can be used in the case where the access_token expires. Another resources that gives additional information:
https://developer.salesforce.com/page/Using_OAuth_to_Authorize_External_Applications

SessionId login failed


Is it efficient to run a linear regulator in dropout mode?

Question: In a battery powered application, it might be tempting to run a LDO in dropout mode as a LiPo battery falls from 4.2V to below 3.3V. Is this a normal thing to do, and would most regulators perform efficiently in dropout mode, or do you just have to select carefully for this quality based on the datasheet?
Comment: I would let it ride the battery down, but I'd pick something closer to the maximum limit of the components so that there's less power dissipation with a full battery.
Comment: @IgnacioVazquez-Abrams many parts draw less current at lower voltages.  So a lower-voltage LDO results in less power usage overall. (since current-in and current-out are about the same for a reasonable LDO.)
Answer: Most CMOS LDO regulators are fine, but some of the older bipolar types with lateral PNP pass transistors draw relatively huge current in dropout. So, yes, it's always good advice to  carefully read the datasheet, and especially so in this case.
Answer: You need to carefully select this.
I looked at this about a year ago.  Lots of linear regulators have high (about 500 μA) waste (ground pin) current when they are in dropout.  This may or may not matter to your battery.
Linear Technology had a part that was nicely characterized for this. Like all LT parts, it was not the cheapest choice.  Sorry I don't have the part number handy.  I think Micrel also had one.
If I may rant, LDO selection tools are really annoying when you're trying to select for a certain characteristic like noise or current drain in dropout.  Instead they only seem to be concerned with dropout voltage... I couldn't care less if it's 100 mV or 50 mV but the marketing department sees "low-dropout" in the name and assumes that's the only spec everyone wants to see.


Redirect map template not working in sitecore 10.2

Question: In Sitecore 10.2 Sxa, I am trying to add redirection rules with redirect map, which is under the settings item.

But when I try to add a  redirect map , redirection does not work. What could be the cause of this?
Comment: Could you please add more information? Also if possible, add the details/steps that you have followed to add redirects.
Answer: It looks like you are using the third party module from sitecorescientist.com:
https://sitecorescientist.com/2018/10/17/redirect-module-for-sitecore-9/
In your screen shot it looks like you have not selected the type of redirect that you want to use. Try changing that to '301 Redirect', republish and test again.
Also, please check that you have completed the setup actions from the github page (for example adding redirectSettingsId to 'website' node in sites config)
If that doesnt work, have you checked that the version of sitecore you are using is compatible with the module? The web page promoting the module suggests its good to use on Sitecore version 9.
If you are using a later version, then you will need to clone a copy of the repository (https://github.com/velan99/SitecoreRedirect) and update the solution to use .Net Framework 4.8 and also the latest sitecore nuget packages.
If you have done all the above, then please double check the sitecore logs to see if there are any clues there.
I just tested the module on using values similar in format to what you have used and it worked as expected.
Answer: Please ensure two things when applying a redirect using a redirect map:

Always specify the type of redirect you intend to use.
Make sure that your old URL or item (in your case, '/NewItem Tests And NewsTestRedirect') does not exist in the content tree. The redirect map only functions when an item results in a 404 error.
Answer: From the drop-down list, select the type of redirect:
Permanent Redirect (HTTP 301) – redirects target resource to a permanently different URL.
Temporary Redirect (HTTP 302) - redirects target resource to a temporarily different URL.
Server Transfer – helps reduce server requests, keeps the URL the same and is not visible to the client. For example, when you want to transfer the current page request to another .aspx page on the same server or when you want to avoid unnecessary roundtrips to the server.


garbage disposal still works but the sink just does not drain

Question: The garbage disposal under the kitchen sink still runs, but the sink just does not drain. What can the reason, do I have to open the garbage disposal? Are there any easy ways to fix?
Comment: Is it a 2-sided kitchen sink, and if so are both sides backed up? Are there any other drain problems? Have there *been* any other drain problems recently?
Comment: If the trap is clogged, you may be able to plunge it from the top. Block the other sink with a rag if there are two. Dishwasher? You may force the waste water into the dishwasher, check inside when you are done. A picture may help.
Answer: In my last house, any time my wife would put large amounts of lettuce or cabbage leaves or similar vegetables through the disposal the discharge drain after the disposal would plug up causing me to have to take the drain apart and remove the plugging. Using a plunger just made the plugging worse since it would only compact the stuff in the discharge piping.
Comment: I had that happen a few weeks ago. The trap was clogged with egg shells when my wife was making deviled eggs for Christmas. I took the trap into the yard and knocked everything out of it.


I am creating a Like button similar to Youtube or Facebook and I am having some trouble with storing unique likes

Question: I have not started creating the code so I don't have anything to show, but what I am going to create is a simple button after each post on my website that allows users to "Like" the post. The only problem I have is figuring out what my MySQL table should look like for this feat. I want to add a 'rating' column in my 'tbl_posts' table that stores the count, but I'm not sure how to make it so that each user can only upvote the post once. Any ideas on how to create the database in this way?
Also, I want to create the "Like" button using jQuery. What do you recommend is the best way to create the Like button.
Gracias.
Answer: I recommend the best way to implement your like button is not to develop a new button, but to use the API:s of facebook to do that.
If you really feel the need to implement it yourself, you should have a UNIQUE column with user id in your SQL table.
Comment: I don't think the OP wants an actual Facebook 'like' button, they want something similar in functionality. At least that's how I interpreted the question.
Answer: If you're talking about registered users on your page you could create a user_likes_post m:n relation between your post and user tables.
If you're talking about page visitors you'll have to resort to IP addresses and/or cookies to make sure everyone can upvote only once.
For the button itself i'd recommend jQuery UI


How to customize ubuntu live cd plymouth theme?

Question: I am planning to customize Ubuntu 13.04 live cd. How is it possible to customize Ubuntu live cd plymouth theme in ubuntu 13.04 ?
Comment: That doesn't answer how to customize the live cd plymouth theme. Some ehere I have read about editing initrd.lz file in the /casper directory, but, such a file is not present in that directory in Ubuntu 13.04 .
Comment: start here: http://askubuntu.com/questions/48535/how-to-customize-live-ubuntu-cd/49679#49679
Comment: it does start the answer (but I did say: -start- here). You can trust me on that one :) The answer I made there is useable for 13.04 except we now work with dconf . You need to create a chroot environment with a downloaded ISO image load that ISO into the environment, alter it and then re-create the ISO. And no this is not something that is easy to do and requires thorough knowledge of the inner working of Ubuntu.
Comment: I think to edit the live cd plymouth we need to edit initrd file, but I couldnt find the same in ubuntu 13.04 iso.
Answer: There's an answer to the following question on here:
How to change Live CD splash screen
Though, editing this file only works on the next non-LTS (13.10)


Electron interference

Question: As I have understood, as per QM, electrons could behave as waves in a double slit experiment, i.e. form dark and bright bands, albeit after sufficient electrons have been shot from the source. Also, I have come to see that gaining information about the "Which slit has the electron passed?" messes up with the original problem to the extent that gaining a certain answer about the latter (with some measuring device) would totally obstruct the interference pattern.
Now my question is that is it not possible to always track a single electrons chosen path with some time keeping scheme. i.e. the time from electrons emission until its detection, and knowing its initial energy (or momentum) to some extent (as would be also revealed from the interference pattern), would reveal the "path" it has taken. Sorry for the sloppy language beforehand and thanks for your help.
Answer: I believe that any measurement which allows the determination of a particular result as a certainty alters the state of the quantum system, the electron in this case, and as a consequence will change the nature of the overall experiment so that one no longer has a "true double-slit experiment", and therefore will no longer see an interference pattern.  If one is able to determine a definite path of the electron by some measurement scheme, no matter when or how, then one has altered the state of the electron and has changed the experiment.
I hope this helps.
Comment: Thanks, but this answer is quite vague since the time from emission to detection is always present and available to the (careful) experimenter and as such, the interference pattern should never be seen.
Comment: @HooshmandKashani  Careful is not sufficient; no amount of care will conserve the entirety of the wavefunction AND also make a determination.

Electron interference


Heavy imposter syndrome

Question: What are best ways/resources to deal with imposter syndrome or runaway thoughts? I recently published a paper (only my 2nd first author) and was excited about it for about 2 mins before I got very bad anxiety over it. I found some novel findings in my paper and so far it has been well received but I keep thinking "I'm proposing a a new thing that hasnt been seen in the field, what if it was a fluke and can't be repeated and I end up losing my career in science." I did my due diligence in the experiments but I have lost sleep over this thought, and have started to doubt myself as a scientist. I don't have insurance at the moment so can't see a therapist but I was wondering if there were online tools to help with this.
Answer: Let me suggest something other than imposter syndrome and that if any such tools exist they probably won't help you.
One common reaction to completing a major piece of work is letdown since your life now seems empty. What was filled with work and the expectation of success now is filled with a big blank.
Another possible aspect is fear of the unknown. You have put something out there, hoping for wide acceptance, but it hasn't yet come, not having time enough yet to be really seen.
But, the reviewers thought enough of the work to recommend its appearance and the editor(s) agreed. So you do have a bit of evidence that you haven't failed.
And even if it can't be reproduced, it needn't be the end of your career if you have done due diligence in your research.
The cure, is easy, actually. (Well, maybe hard.) Just go back to work. Talk to any collaborators and come up with some ideas that might be developed into the next big piece of your career. Then, just get it done. Simple.
Comment: I appreciate this. I just actually started a new job and I am working on designing new experiments. I keep trying to tell myself that even if it isn't well received or reproducible it won't be the end of the world because such is the nature of science. Will keep pushing forward

Heavy imposter syndrome


Sample size calculation for multivariate problems

Question: I am interested in multivariate investigations. I have been trying to learn about designing such experiments where there is one dependent variable (a class/group) and many independent variables that ideally would help discriminate between the groups. However, the 'basic' issue I am running into is the problem of sample size calculation. I have been pouring through literature to see if there is a consensus how to calculate sample size for a multivariate investigation. Does anyone here know of a method to accomplish this task? I am primarily familiar with the R program but I am also competent with SAS and the Python programming language. Is anyone familiar with this task?
Comment: Framing the task as the very general "multivariate investigation" won't be enough:  you'll need to narrow things down to a specific procedure and then you'll be able to find specific help on sample size / power analysis.
Comment: Some general guidelines is what I am after.  I recognize that each case is specific and requires fine tuning.  I'm just trying to find a place to start, some calculations, literature, etc.
Answer: Sample size calculation is a part of power analysis. There are two general ways to approach a power analysis: You can rely on some canned program or you can simulate.
To rely on a canned program, you will need to know what test you are using (e.g. linear regression, logistic regression ....), the effect size that you want to be able to detect, and your tolerances for type I and type II errors.
Then, all three of the programs you mention have programs to do power analysis. SAS, for example, has PROC POWER and PROC GLMPOWER.


How to outline a brush in Photoshop

Question: Is there any way to add an outline to a brush so that when stroking a path it will give a sense of depth and layering where the path overlaps?
As an example, here is an image of footprints. How could I add depth so that you can tell which footprints came later on (i.e. on top of other footprints)
Answer: I'm going to answer this question based on the comment thread that happened on a deleted answer, where Sean said:

Thanks, but what I mean by depth isn't the bevel and emboss 3D, I just
  meant layering; how it makes one footprint look like it's on top of
  another.

There are numerous ways to create a sense of "depth". As Scott mentioned, opacity is one technique. Any elements towards the bottom would have a lower opacity and elements stacked on top would have a higher opacity. The only draw back is that earlier footprints may be difficult to see and eventually, you will reach a maximum opacity.
Another alternative is to use different layers of footprints (separate the footprint paths based on walking from point A to point B.) Then you can add layer effects to emphasize depth. This includes drop-shadow and stroke. This approach takes a little bit more work, but you'll have more control over the result.
In the end there isn't a one-click solution that'll make your dreams come true (yet). for now you'll have to do some manual work to achieve the depth that you want to see.
Something else I might suggest is using less footprints overall, as it looks pretty cluttered as-is.
Answer: No, but you could stroke paths individually as 'subpaths' instead, then apply a layer FX or a layer style for shadows or an outline.
Answer: Paint on a layer by itself and lower the opacity of the brush.
Having a tablet such as a Bamboo or Intuos would allow you to control opacity as you paint, lending to the "overlapping" impression more.
Answer: you may define your own brush, by keeping the strokes black and middle area light grey. I have just tested it, hope it will do the trick for you.
Answer: just color them differently: darker to lighter. LIghter being at top.

How to outline a brush in Photoshop