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Plant Sciences, Zoology & Evolution / what's the evolutional advantage of our having fingers of different lengths?

« on: 20/04/2015 04:05:58 »

I'm curious as to the evolutional advantage of human fingers having different lengths. Why is it so? And what would happen if they were all of the same length?

2

General Science / Why are bricks rectangular, not triangular?

« on: 05/08/2014 02:45:29 »

Triangle is the most stable polygon in geometry. I'm wondering why then the building bricks are all rectangular, not triangular?

3

Plant Sciences, Zoology & Evolution / Why does a giant squid have huge eyes?

« on: 16/03/2012 04:13:18 »

I was listening on the radio this afternoon, and one interesting story was about the giant squid having the world's largest eyes of any animal (the size of a basketball). There have been lots of debates about why their eyes are so big. Researchers have made calculations for what various eye sizes would allow the giant squid to see in the depth of the ocean where it's total darkness, and they assert that a much smaller eye would have served the squid well in its natural habitat. So far, it remains a open problem.

What are some of th competing theories/conjectures about the giant squid's disproportionately huge eyes? Thanks.

4

Plant Sciences, Zoology & Evolution / Are there any birds that travel long distance (hundreds of miles) alone?

« on: 27/08/2011 23:07:45 »

Hello,

   The birds that seasonally migrate a long distance (hundreds of miles) all seem to be traveling in flocks. Are there any birds that travel such long distace alone? f not, perhaps, it's because group travel has advantages over single travel, e.g., safer than individuals, less tiresome (airstreams from others' wingtips help staying afloat), etc?

   Do we know of any birds in the history of evolution that had the ability of travel long distance alone?

   Thanks.

   

5

Technology / Why's my digital camera unable to faithfully capture various dynamics in music?

« on: 25/08/2011 03:58:06 »

I have a Sony Cybershot DSC-T700 digital camera. As an amateur pianist, I often use its video-recording function to record me playing the piano. In a piano piece, you play different dynamics at different passages, sometimes pianissimo, sometimes a little more forte, that sort of things.

I'd like to think I do a fairly good job playing these different dynamics. However, after recording a piece and playing it back, I often find that the recorded audio does not faithfully capture the various dynamics.

It could certainly be that I'm not playing the dynamics well enough, but I'm also wondering whether it could be that the audio recorder in the camera is too rudimentary to do that. Anybody have any ideas?

And, what about a digital camcorder? Would it have a better audio-recording system built in to do a better job of capturing the dynamics?

Thanks.   

6

Plant Sciences, Zoology & Evolution / Could polar bears and penguins switch places?

« on: 16/10/2010 04:23:10 »

I'm wondering if polar bears and penguins could switch their places and still live and populate. Why or why not?

7

Physiology & Medicine / How do human eyes and ears receive visual/audio signals?

« on: 11/10/2009 00:21:12 »

Hi,

    I'm hoping someone on this forum can give me some tutorial (both online and off) on how human eyes and ears receive visual and audio signals from the outside world. I'm very new on this, and so would like to read something elementary to begin with. Thanks.

8

Technology / Can we model the future of energy provisioning after the Internet?

« on: 08/04/2009 02:40:12 »

I attended a talk today here at Cornell University by Robert Metcalfe, the inventor of the Ethernet. He talked about the concept of Enernet, a concept in which the future of energy generation, distribution, and utility is envisioned to be modeled after today's Internet. For example, it may have a layered structure, similar the Internet OSI protocol stack, and the management of the energy supply may take various approaches, e.g., centralized vs. distributed.

I find this concept fascinating, since I'm not in any energy-related field of study (my background is wireless communications), and never thought of the Internet as a template for another type of infrastructure (Internet is still, in my opinion, not mature enough). I wonder if anybody on this forum may have some thing to say about this concept. Specifically, is there any trend, or some tiny evidence, in the energy sector that seems to validate this Enernet concept? 

Thanks.

9

Geek Speak / How to carry user-defined fig./eq. labels in a MS word file to another computer

« on: 07/01/2009 04:38:18 »

Hi,

    I wrote a paper using MSWord 2003 on my office computer, in which I defined some figure, equation, and table labels (from Insert-->Caption-->New Label). I then transferred the word file to a different computer, and opened it to expect these defined labels to be there (Insert-->Cross Reference -->(user-defined labels)). But they are not. As a result, I had to re-define all these labels on the new computer.

    Granted that the second computer has MSWord 2000, I don't think different versions of MS Word is the culprit. Does anybody know what I should do in the computer where I defined these figure/table/equation labels so that when I work on a different computer, these user-defined labels would come along?

     Thanks a lot for your help.

10

Physics, Astronomy & Cosmology / Is a practical cloaking device prototype possible within the next 20 years?

« on: 03/09/2008 23:22:46 »

Hi,

   Do you think in our lifetime we may see the production of a practical cloaking device prototype? A cloaking device that may be as large as one to hide a Klingon bird of prey, or as small as Harry Potter's invisibility cloak? I understand there have been some advances in pursuing this goal in the last couple of years. Being someone with almost a complete lack of background in optics, I certainly appreciate people knowledgeable on this topic to "shed some light" on it. I'm interested to get some discussion how likely a cloaking device is realizable, what are the current physical limitations, etc.
   
   I also came across an interesting article today:

http://technology.newscientist.com/article/dn14659-anticloak-gives-vision-to-the-invisible.html?DCMP=ILC-hmts&nsref=news3_head_dn14659

It proposes a new theory of "anti-cloaking device." Namely, the theory of a cloaking device blocks out all the lights that shine upon some object, rendering it invisible. This also would mean that the object would be in total darkness and would not be able to see outside either. That would limit the applicability of the cloaking device.
This article proposes a theoretical approach that allows some light to go through the cloaking device in a smart way that, on one hand, maintains the invisibility of the object, and on the other hand, allows the object to see the outside world as well.

    I find this article interesting, and I never thought about this "anti-cloaking" idea before. I would like get some feedback on this forum to enlighten myself on this subject.

    Thanks.

11

Technology / how to solve the following linear curve fitting problem in the minimization cont

« on: 24/08/2008 08:02:56 »

Hello,

    First off, I apologize for posting this math question because I know this is not the right forum for it. But I appreciate it if anybody could help me with it. Or if you know of another forum more appropriate for this question, please let me know.

    Let's first limit ourselves to only the first quadrant of a Cartesian coordinate system. I have a point G that's located on the x-axis, and it's position (x_G, 0) is known (x_G>0). Now, I have four points A, B, C, and D in this quadrant, and I can measure the four distances GA, GB, GC, and GD.

    The four distance measurements each contain some errors. But if error-free (as shown in the attached figure below; I accidentally posted it twice), they're supposed to be all on a straight line, i.e., a linear trajectory (i.e., the line can be described as y=ax+b). Moreover, these four distances are periodically sampled, meaning that (in the error-free case) AB=BC=CD. And, just for the sake of the argument, let's say GA>GB>GC>GD. However, I do not know the coordinates of these four points in the Cartesian system (denoted as (x_A, y_A), (x_B, y_B), (x_C, y_C), (x_D, y_D), respectively).

     I want to find the slope of the linear trajectory in the Cartesian system. The way I'm thinking about doing is to cast this as a minimization problem to first find the points' coordinates on the linear trajectory (denote them as (x'_A, y'_A), (x'_B, y'_B), (x'_C, y'_C), (x'_D, y'_D)). That way, the slope can be estimated to be = (y'_A - y'_B) / (x'_A - x'_B).

    However, I'm not familiar with formulating the minimization (what should be the objective function, and what should be the constraint function). Can anyone help me with this? Thanks in advance.
[diagram=361_0][diagram=361_0]

12

Geek Speak / How to develop a good methodology to test new search engine (e.g., cuil)?

« on: 30/07/2008 17:07:58 »

When cuil (cuil.com) was released earlier this week, I tried it, and frankly, was not very impressed with its capabilities. It has made some mistakes when searching for my queries, and sometimes, it wouldn't return any hits at all, even though the same string of keywords returned lots of hits when using google. So, cuil still has a few kinks to be worked out.

Anyways, I'm curious if anybody (or better yet, someone who actually works at google) can share with us some idea on how to systematically test the underlying strengths and weaknesses of a new search engine? The way I did it with cuil,I  randomly chose some key words and compare the search results with google. Fortunately, the current state of cuil is bad enough for me to realize it's still got problems. But suppose if it were pretty good, how then should I be testing its performance?

Any ideas? Thanks.

13

Physiology & Medicine / Are there other animals that use pillows in their sleep?

« on: 30/06/2008 14:22:44 »

Hi,

    My post has actually two parts:

    1) why will we humans feel uncomfortable if we sleep without a pillow? How does the pillow help in terms of soothing brain activities while asleep?

    2) I wonder if other animals (perhaps more specifically, primates) have been observed to use pillows in their sleep? If so, is there some kind of evidence to correlate the intelligence of a brain with the use of pillows? Maybe a zoologist can help with this one?
   
    Thanks.

   

14

Technology / Can you control a robot arm by thought alone?

« on: 28/05/2008 19:27:18 »

An interesting article on today's NY Times:

http://www.nytimes.com/2008/05/29/science/29brain.html?hp

It's about a monkey using its (his) thought to control a robotic arms. The article also has a short video clip accompanying it. The experiment is published in the latest issue of Nature. I thought it was pretty cool monkey business.

[MOD - subject re-formatted as a question, in line with forum style - CS]

15

Physiology & Medicine / Why do I wake up sometimes with my heart pounding strongly?

« on: 22/02/2008 16:24:11 »

I often have the experience that when I suddenly wake up in the middle of the night (e.g., from a nightmare), I could feel strongly my heart pounding in my chest. And I mean really strong. Why does that happen? Thanks.

16

Geek Speak / Can cooling computer DRAM preserve the content and constitute a security risk?

« on: 22/02/2008 15:00:12 »

There is an article in today's New York Times. The Princeton researchers find that when cooling the DRAM in the laptop immediately after it's powered off, you can keep the data stored in DRAM intact for a few hours, which provides ample time for potential data theft.

Furthermore, there is a video clip from the Princeton group in the following URL for the demo:

http://citp.princeton.edu/memory/

There's also a technical paper on that website if anybody's interested.

17

Technology / Driving with GPS and Galileo

« on: 07/02/2008 01:56:57 »

Hi,

   I'd like to get some user experience input from this forum about driving in the U.S. and Europe with GPS and Galileo navigation systems. I've never driven in Europe, only in the U.S. with commercial GPS products. Some pertinent GPS UI features include 1) current location of the car, 2)the directions to your destination (including also self-correction and recomputation if you made a wrong turn), 3)information about gas stations, restaurants, tourist landmarks, 4)some early warning to tell you to turn before you get to the intersection, and 5)language selection (English, French, and Spainsh mostly). And there is the voice instruction for giving directions so you don't have to stare at the LCD screen when driving.

    Do people in Europe have the similar features on their Galileo navigation products? Are there any features on Galileo that are not supported by GPS (I'm talking about the commercial products, of course)?

    Also, when you drive from one country to another, do you experience any difference in getting the Galileo services? I mean, for instance, would Galileo signals be not available even under the clear open sky, because of some local laws?

    I'm interested in learning how Galileo works for European drivers these days. Also, does anybody have experience driving in Asia, South America, Russia, etc. with either GPS or Galileo or any other systems? I'd very much like to know the driving experience there. Thanks.

18

Geek Speak / Surface Computing at Microsoft

« on: 28/10/2007 03:29:54 »

Here's a video clip of a new paradigm of computing called surface computing, developed by Microsoft. Although some ideas of it are not that novel (having been around for a couple of decades), the implementation is pretty neat.

http://link.brightcove.com/services/player/bcpid932579976?bclid=932553050

19

Physics, Astronomy & Cosmology / How the expansion of the universe is determined

« on: 13/08/2007 14:40:29 »

Hello,

    I posted this question a couple days ago in an older thread in the General Sciences section.

    From our observation of the light we know the universe is expanding (due to the so-called redshift in the observed wavelength). Presumably, the light that we've observed was originally emitted some billions of years ago, right? If that's the case, we can claim that billions of years ago, the universe was in an expansion mode. How then can we say it's still expanding today? Why could it not be in the contracting mode now?

    If, on the other hand, the light that we observed and used to determine the universe is expanding emitted only a few hundred years ago, that implies that the source of the light is only a few hundred lightyears away from Earth, which is quite a local area on the cosmological scale. Then we could only claim that this area of the universe is expanding currently. How then can we apply this claim to the universe as a whole?

     I'm sure I must have missed something here. Can someone fill me in on this? How was measuring the expansion of the universe actually carried out? Thanks.

20

Physics, Astronomy & Cosmology / How big is Earth when compressed

« on: 09/08/2007 05:37:31 »

I'm curious to know: If the whole of Earth were compressed as tightly as possible (i.e., no spacing between molecules), how big would it be? Assume that we exclude all living things on earth, but include water.

Anyone can offer a reasonable guesstimate? Thanks.