The body is small compared to the signal wavelength (2m/200m=0.01 wavelength), which means it absorbs almost none of the radiated power.
Absorption doesn't have that much to do with the wavelength. The dye molecules in printing ink are a factor 1000 smaller than the wavelength of visible light, but that does not hinder them from absorbing light quite effectively. Or try cooking small pieces of food in the microwave oven (wavelength 12 cm).
Here are the facts: sea water has an absorption coefficient of 0.1/cm for 1 MHz EM radiation (typical AM radio). Pure water has much less absorption (about 0.001/cm) due to the absence of ions which can be shaken around by the radiation. I estimate that the human body (10x less salt than the sea) has an absorption coefficient of 0.01/cm. That means that you (20 cm thick) will absorb 20% of the AM radio power that passes through you. I don't think that standing next to a 50 kW transmitter is very healthy.
(At 1 GHz (mobile telephony), the absorption coefficient is about 1/cm.)
I personally think that it doesn't make sense to make calculations about the absorbed power, because if low-intensity RF radiation has a biological effect at all, it won't be the heat production. It might have to do with dissolved ions being shaken around, which interferes with chemical reactions in the cell.
It is more reasonable to use the field strength as a measure instead of power and field strength drops as 1/r in the far field (>300 m). Comparisons with other sources of radiation (mobile phones, TV broadcasts, sun light) don't make sense either because the biological effects, if any, are likely to be very frequency-dependent. After all, X-rays are EM radiation, but you don't need much of those to get cancer.
Back in January 1999 when everybody used telnet for remote logins, several computers in our department were root-compromised and had a rootkit installed (password sniffer, backdoors, and patched versions of ps, ls, and such to prevent being detected). We noticed some strange activities but had no clue what was going on, thinking that other people were trying to intrude us, while actually the cracker used our computers to intrude other people. It felt a bit like being in a thriller, where we step by step discovered what was going on, culminating in a session where we witnessed live how the cracker was logged in on one computer, from which he tried logging in on a second computer where we already had changed all passwords. We contacted the internet provider (he was behind an IP-masquerading firewall) and an university where he apparently illegally had plugged in a computer on the network and of course the cracker had been reading a number of emails before we finally locked down our systems.
Since then, our computers got enormous attention from crackers, while suspicious messages appeared much more seldomly in other people's log files. This cracker was severely pissed off. We were compromised several times after that. Once, the presence of a rootkit revealed itself through the fact that an ls option wasn't working anymore. We repaired the situation and removed telnet/ftp from the computer (they had suspicious log file mesages), not knowing that it was the outdated sshd that caused the trouble. After the weekend, the owner of the computer came to me complaining that he couldn't log in. It turned out that the intruder wiped his whole home directory, which had no recent back-up! I can not believe that a cracker does something like that for any other reason than pure revenge.
These incidents have taught me the value of staying up-to-date. What I wanted to tell here is: don't let the cracker know that it was you who caused them trouble or you might get repercussions. Oh, and note that I am not a professional system administrator; I was a PhD student who happened to know a bit more about Linux than most others.
I actually used 24-bit PNG, but as I already mentioned: I had no anti-aliased fonts and apart from a few small icons no continuous-tone images. A window with bitmap fonts has just white and black pixels (easy to compress in PNG, hard for JPG); a window with antialiased fonts has all possible shades of grey (hard for PNG, easier for JPG). If I take a screenshot of Mozilla with its antialiased fonts and the slashdot home page, it looks like this:
Some time in the future, I would imagine that disk space will become so cheap and abundant that lossy compression is unnecessary,
Unfortunately, by that time, everybody can afford a digital camera that does 3-dimensional pictures (or video clips) with 24 megapixel/48 bit, and music is distributed as 17-channel/192 kHz/24-bit surround-sound.
Take a high resolution screenshot with any complexity and save it as a PNG, and you might be lucky to get it in under 600KB, where a.jpg could get the same point across in under 100KB.
I tried it, 1536x1152 PNG, JPG (q=75%), JPG (q=95%).
$ls -l -rw-r--r-- 1 hankwang hankwang 99438 Aug 12 11:49 ss.png -rw-rw-r-- 1 hankwang hankwang 236158 Aug 12 11:50 ss75.jpg -rw-rw-r-- 1 hankwang hankwang 404179 Aug 12 11:50 ss95.jpg
Apart from the bigger filesize, JPG shows ugly artifacting. Note: I don't use too many antialiased fonts, and no fancy backgrounds and skins. If most of your desktop is covered by a photographic JPG image in the first place, you will find different results, of course.:)
It's good to see what the people behind this project have been thinking of - when stuff ends up in press releases it is sometimes inflated beyond recognition, which I was suspecting in this case.
The essential numbers in the paper are: 1500 photons captured per pulse in a big telescope from 1000 light years distance, which is a factor 1e4 above the sun background within a 3 ns time window. According to the paper, the detector actually often registers such flashes due to various causes which are not likely to be extraterrestial civilizations.
Now suppose that you find a flashing star. What kind of messages would a civilization encode in these flashes? The transfer rate is limited to a couple of bytes per second at most.
The sun radiates with about 2e25 watts per steradian. That's of course an incredible amount of light, so the idea is to use fewer watts within a very narrow angle. The claim is that one can achieve 2e29 W/sr that way.
The divergence of a laser beam is, assuming ideal optical components, mostly dependent on the diameter of the beam where it starts. You can take a big telescope and let the light pass through in the opposite direction, so let's say, a diameter of 4 meters. For visible light, that will generate a beam with a divergence of 1e-14 sr. So, to get to 2e29 W/sr, you need a laser with a power of no less than 2e15 watts. (Compare this to a mid-size electrical power plant at 1e9 watt...)
Yes, there exist lasers that can generate ultrashort pulses in the near-infrared, with such a high peak energy, say 100 femtoseconds (100 fs=1e-13 s) and 100 joules per pulse, so there you have our desired fluence.
Unfortunately, such lasers can only fire something like one shot per second. If you really want to appreciate the high peak power, you need a camera with a shutter time of 100 fs. Imagine looking at the sky with such an ultrafast camera. The chance that you actually manage to catch a flash from this laser is virtually zero, unless you have a way to know when the flash is going to come. Someone who is looking at a nearby star and expecting flashes is more likely to have an aperture time of 0,1 seconds or so in order to capture any photons at all. At 0,1 seconds aperture time, the laser is no longer 10,000 times more bright than the nearby star (that is, our sun), but rather 1e8 times weaker.
So, it is unlikely that this is going to word, assuming that someone is looking at us anyway.
You can't encode MP3s above 56kbps without paying a licence fee to Fraunhofer-IIS.
Unless FHG changed the rules in the past couple of months, the license-fee structure is something like this:
Selling encoded music: 3% (or so) of what you charge for the music
Selling an encoder: a fee per software license if you *sell* it. The lame encoder can be used legally for free because you don't have to pay for it. There are issues with distributing a compiled version, though.
Selling a decoder: a fee per decoder ($1 or so).
There is a minimum amount of money you have to pay in license fees (a 5-digit number), but only a company that sells for more than $50,000 or so per year needs to pay any fees at all.
You as a private person are perfectly allowed to encode MP3s. You can even legally sell the MP3s as long as you stay below the treshold (provided you don't violate copyright issues with the music itself, of course:-) ).
I have never seen any specs for a studio mic rated at 20 kHz. [...] you'll see it's at least 10 dB down at that frequqncy.
Expensive studio mics reproduce the full range 20-20,000 Hz and leave it to the sound engineer to
filter out high frequencies if necessary. Here's a real studio mic, a Neumann U89, -4 dB at 20 kHz (see PDFs under "Documents"). Good for about $3000. Or, an order of magnitude cheaper, Audio-Technica AT853a.
I sometimes use the latter type for making live recordings of chorus performances on minidisc and apparently, the white-noise background also extends to 20 kHz. It seems that the Atrac-compression (350 kbit/sec) has a hard time with the noise because you don't need golden ears to hear the compression artifacts.
Take any industry grade centrifuge... it takes a very long time to enrich 238U, but it can be done.
It depends on what you call "very long time". In the centrifuging, you have to beat diffusion by the centrifugal forces. At 5000 RPM in a 10-cm radius, you have an accelleration of 27000 g. That sounds like a lot, but you have to compare the thermal energy kT to the "gravitational" energy gained by moving a molecule over a few cm (about 1e-5 times kT for U235 and 1.01e-5 kT for U238). If you start with 1% U235 and 99% U238, then this centrifuge will give you 1.0000001% versus 89.999999% as the enriched product and 0.9999999% versus 90.0000001% as the enpoored product. Repeat this about 10 million times to get a 50%-enriched product. Of course, you have to re-centrifuge all the "poor" fractions and feed them back into the system, or you will end up with about ten atoms of purified U235, so in fact you must roughly square the number, which means about 1e14 processing steps. I'd call that impossible, not just a matter of patience.
I have once had the opportunity to see the Dutch uranium enrichment plant Urenco from the inside. They enrich up to 5% (reactor-grade uranium) and their centrifuges spin much faster - how fast and what technology they use is top-secret. The result is that they need "only" a couple of ten thousand centrifuges: a large sports hall full of 4-meter-high cylinders.
So, you set it to explode after it starts to fall a few feet. It's going to slow on the way up, then speed up again on the way down.
If there is no propulsion or significant air drag, the acceleration is 9.8 m/s^2 (the gravitational acceleration g) regardless of whether it's going up or down.
Red+Green+Blue light _looks_ white to us [...] White light contains all frequencies of visible light.
This is a silly distinction. The term "white" is defined by what the human eye can see, as you already indicate by mentioning "visible light". Hence, if it looks white to the eye, it is white, by definition.
If I really nitpick, then "white light" does not exist at all, since the sensation of white results from your brain comparing the color sensation from an object to its surroundings. A piece of white paper can emit light with a vastly different spectrum (with vastly different responses in your retina) depending on whether it is illuminated by daylight, incandescent light, or fluorescent-tube light, but it always looks white because of what your brain does.
Europe uses 230 V these days. I have no idea why, but they do.
The UK used to have 240 V and the mainland 220 V. About 10-15 years ago, it was changed into the average of the two (230 V) such that there is one single standardized voltage in whole Europe. (Never mind that the voltage depends on the distance to the nearest transformer as well)
Six Megapixel. You can print out an 8X10" photo at the same quality as 35mm film.
In the past six years, I have ordered a print at that size only twice. And they were pretty blurry (taken with a mid-range compact camera) if you look at them from close by (what I usually don't do with pictures that hang on the wall).
An expensive camera does not give you good pictures if you don't know how to create a good composition.
Has a nice optical zoom. [...] I think 10X or more.
I hardly ever zoom in all the way on my 3x zoom. The light sensitivity drops and camera shake is amplified, which means blurry pictures unless I use a tripod. More expensive lenses may not drop in light sensitivity, but the problem of camera shake is still there. I'm more bothered by the lack of wide-angles on these cameras, which usually are equivalent to f=38 mm instead of the f=28 mm on my film roll camera.
The biggest plus for me of a 2 MP digital camera is that is small, light, and cheap. I can always carry it without being too worried that it breaks or gets stolen.
Don't want to run some bloated window manager? Then don't! I'm using fvwm95 right now and it's only using a few MB of ram.
Tell me how you did that! I've stubbornly been running fvwm2 up to a few weeks back. The reasons for ditching it were:
Not cooperating with Qt in Opera 7 (O7 hogs the X server on each focus/unfocus event when invoked under fvwm2)
It didn't with most gnome tools. It can't read the menu configuration, so you have to guess which programs are available, and if I run some gnome program (was it eyeOfGnome?) I the whole gnome desktop gets started first.
I would be glad to go back to fvwm. I'm stuck with FC1/Gnome/Metacity and it took me damnit half a day to figure out how to customize the start menu and to add an extra menu to the task bar. Adding/customizing menus requires creating a zillion ini-files - one for each menu item and some poking in human-readible-but-not-human-writable XML files.
Shred is only for the real paranoid. Recovering overwritten data from a magnetic medium is theoretically possible, but there is no evidence that anyone actually succeeded in doing that in a practical situation. It would require a scanning-tunneling microscope (about $100,000) and the bitrate would (my guess) be in the kbit/s range, so recovering a 40 GB harddisk would take about 1 year, assuming 10 kbit/sec.
With this,
dd if=/dev/zero of=/dev/hdb bs=1048576
or
cat/dev/zero >/dev/hdb
you will just write zeros and it will be 25 times faster than using shred.
Encrypting will make it harder to recover passwords, but the encryption key is still somewhere in the memory. An attacker with root permissions may be able to peek at a live memory image in/proc. I'm not sure where it is nowadays, but in the linux-1.0 days there used to be this huuuge 8 MB file in/proc and otherwise you can always insert a kernel module that does the job. An attacker who is willing to figure out the format of the swap space AND of the user program's data memory won't have a problem with creating a kernel module.
All the ISPs are going to start filtering outbound port 25. If you want to run your own mail server you'll have to route it through their mail server
And the next generation of zombie programs will do a simple DNS lookup for the mailserver of the current domain and start sending spam through the ISP's mailserver.
With the side effect that in no time no single customer of that ISP can send mail because the mail server is on every blacklist you can imagine.
get the server room shielded with wire mesh built into the walls and conductive film on the windows..
That won't block the radiation from the cellphone tower. Try wrapping your telephone in aluminum foil, just the small hole that you need to see the signal strength indicator is enough to get 5 bars of signal strength.
I don't think that either the cellphone tower or the power lines will cause lots of interference. As others pointed out, the cellphone is too far away to be of concern. You standing next to the router box phoning to tech support will generate orders of magnitude more interference.
The 50 Hz from the power lines is rather low-frequency and also low intensity. Unlike a cellphone station (10s of watts) or a radio transmitter (many kilowatts), power lines are not designed to emit as much EM radiation as possible. All electronics equipment should be designed to handle a bit of 50-Hz noise or otherwise the equipment would freak out if there is a mains cable lying in the neighbourhood of a data cable.
Too bad the inverse square law doesn't apply for the high voltage power lines. It will just fall off as 1/r (where r is your distance from the lines)
Almost right... It would be right for a single wire, but here, you have multiple wires, half of them carrying positive voltage and current, and the other half of them a negative voltage and current. These will partially cancel out, giving you 1/r^2 instead of 1/r (for point sources it would be 1/r^3 instead of 1/r^2).
Note that the above is for field strength at distances from the source shorter than the wavelength (6000 km at 50 Hz). For a cellphone tower, with the much shorter wavelengths (10 cm), the intensity drops as 1/r^2, but the field as the square root of that (1/r). Electromagnetic radiation follows rules different from those for (almost-)static fields.
Water helps keeps the brain 'on task', it flushes impurities from your body
Myth. There is no scientific evidence supporting
that humans need to drink large amounts of water
that the thirst response of your body has a fundamental misadjustment. (An exception may be extremely intensive sporting, but not normal day-to-day life)
that impurities are flushed from the body more effectively if you drink more. That is not how the kidneys work.
Drink water or products with a large water content when you feel thirsty. Excessive water intake can lead to loss of minerals.
Consume no more than 20 grams of fat (not FAT32) per day
This is a modern belief, especially prevalent in the USA, which is quite disputable. All experts agree in any case that saturated fats and trans-unsaturated fats are unhealthy. However, cis-unsaturated and polyunsaturated fats (roughly the ones that are liquid at room temperature) are not unhealthy per se. Fats are digested much more slowly than carbohydrates, which makes you feel saturated for a longer time after a meal.
Limit alcohol consumption to one occasion per week.
Moderate intake of alcohol has been proven to have a positive effect on heart and blood vessels. The negative effects of alcohol on the liver start only at higher intakes. Moderate here means up to 2 standard glasses (e.g. 100 ml wine or 250 ml beer) per day for males and 1 for females. Essential here is that there is a small amount of alcohol in the body most of the time, so spread out the alcohol intake as much as possible over the days. If you drink red wine, you'll get the additional benefits of the flavonoid anti-oxidants as well.
Of course, it's true that alcohol carries a lot of calories.
Slashdot Mirror
Absorption doesn't have that much to do with the wavelength. The dye molecules in printing ink are a factor 1000 smaller than the wavelength of visible light, but that does not hinder them from absorbing light quite effectively. Or try cooking small pieces of food in the microwave oven (wavelength 12 cm).
Here are the facts: sea water has an absorption coefficient of 0.1/cm for 1 MHz EM radiation (typical AM radio). Pure water has much less absorption (about 0.001/cm) due to the absence of ions which can be shaken around by the radiation. I estimate that the human body (10x less salt than the sea) has an absorption coefficient of 0.01/cm. That means that you (20 cm thick) will absorb 20% of the AM radio power that passes through you. I don't think that standing next to a 50 kW transmitter is very healthy.
(At 1 GHz (mobile telephony), the absorption coefficient is about 1/cm.)
I personally think that it doesn't make sense to make calculations about the absorbed power, because if low-intensity RF radiation has a biological effect at all, it won't be the heat production. It might have to do with dissolved ions being shaken around, which interferes with chemical reactions in the cell. It is more reasonable to use the field strength as a measure instead of power and field strength drops as 1/r in the far field (>300 m). Comparisons with other sources of radiation (mobile phones, TV broadcasts, sun light) don't make sense either because the biological effects, if any, are likely to be very frequency-dependent. After all, X-rays are EM radiation, but you don't need much of those to get cancer.
Back in January 1999 when everybody used telnet for remote logins, several computers in our department were root-compromised and had a rootkit installed (password sniffer, backdoors, and patched versions of ps, ls, and such to prevent being detected). We noticed some strange activities but had no clue what was going on, thinking that other people were trying to intrude us, while actually the cracker used our computers to intrude other people. It felt a bit like being in a thriller, where we step by step discovered what was going on, culminating in a session where we witnessed live how the cracker was logged in on one computer, from which he tried logging in on a second computer where we already had changed all passwords. We contacted the internet provider (he was behind an IP-masquerading firewall) and an university where he apparently illegally had plugged in a computer on the network and of course the cracker had been reading a number of emails before we finally locked down our systems.
Since then, our computers got enormous attention from crackers, while suspicious messages appeared much more seldomly in other people's log files. This cracker was severely pissed off. We were compromised several times after that. Once, the presence of a rootkit revealed itself through the fact that an ls option wasn't working anymore. We repaired the situation and removed telnet/ftp from the computer (they had suspicious log file mesages), not knowing that it was the outdated sshd that caused the trouble. After the weekend, the owner of the computer came to me complaining that he couldn't log in. It turned out that the intruder wiped his whole home directory, which had no recent back-up! I can not believe that a cracker does something like that for any other reason than pure revenge.
These incidents have taught me the value of staying up-to-date. What I wanted to tell here is: don't let the cracker know that it was you who caused them trouble or you might get repercussions. Oh, and note that I am not a professional system administrator; I was a PhD student who happened to know a bit more about Linux than most others.
I actually used 24-bit PNG, but as I already mentioned: I had no anti-aliased fonts and apart from a few small icons no continuous-tone images. A window with bitmap fonts has just white and black pixels (easy to compress in PNG, hard for JPG); a window with antialiased fonts has all possible shades of grey (hard for PNG, easier for JPG). If I take a screenshot of Mozilla with its antialiased fonts and the slashdot home page, it looks like this:
That is, PNG takes 0.27 bytes/pixel, whereas my original post (few colors) was 0.056 bytes/pixel.Weird, there is little correlation between how much thought and time I put in a reply and how it is moderated.
Unfortunately, by that time, everybody can afford a digital camera that does 3-dimensional pictures (or video clips) with 24 megapixel/48 bit, and music is distributed as 17-channel/192 kHz/24-bit surround-sound.
I tried it, 1536x1152 PNG, JPG (q=75%), JPG (q=95%).
Apart from the bigger filesize, JPG shows ugly artifacting. Note: I don't use too many antialiased fonts, and no fancy backgrounds and skins. If most of your desktop is covered by a photographic JPG image in the first place, you will find different results, of course.The essential numbers in the paper are: 1500 photons captured per pulse in a big telescope from 1000 light years distance, which is a factor 1e4 above the sun background within a 3 ns time window. According to the paper, the detector actually often registers such flashes due to various causes which are not likely to be extraterrestial civilizations.
Now suppose that you find a flashing star. What kind of messages would a civilization encode in these flashes? The transfer rate is limited to a couple of bytes per second at most.
The divergence of a laser beam is, assuming ideal optical components, mostly dependent on the diameter of the beam where it starts. You can take a big telescope and let the light pass through in the opposite direction, so let's say, a diameter of 4 meters. For visible light, that will generate a beam with a divergence of 1e-14 sr. So, to get to 2e29 W/sr, you need a laser with a power of no less than 2e15 watts. (Compare this to a mid-size electrical power plant at 1e9 watt...)
Yes, there exist lasers that can generate ultrashort pulses in the near-infrared, with such a high peak energy, say 100 femtoseconds (100 fs=1e-13 s) and 100 joules per pulse, so there you have our desired fluence.
Unfortunately, such lasers can only fire something like one shot per second. If you really want to appreciate the high peak power, you need a camera with a shutter time of 100 fs. Imagine looking at the sky with such an ultrafast camera. The chance that you actually manage to catch a flash from this laser is virtually zero, unless you have a way to know when the flash is going to come. Someone who is looking at a nearby star and expecting flashes is more likely to have an aperture time of 0,1 seconds or so in order to capture any photons at all. At 0,1 seconds aperture time, the laser is no longer 10,000 times more bright than the nearby star (that is, our sun), but rather 1e8 times weaker.
So, it is unlikely that this is going to word, assuming that someone is looking at us anyway.
Unless FHG changed the rules in the past couple of months, the license-fee structure is something like this:
- Selling encoded music: 3% (or so) of what you charge for the music
- Selling an encoder: a fee per software license if you *sell* it. The lame encoder can be used legally for free because you don't have to pay for it. There are issues with distributing a compiled version, though.
- Selling a decoder: a fee per decoder ($1 or so).
There is a minimum amount of money you have to pay in license fees (a 5-digit number), but only a company that sells for more than $50,000 or so per year needs to pay any fees at all.You as a private person are perfectly allowed to encode MP3s. You can even legally sell the MP3s as long as you stay below the treshold (provided you don't violate copyright issues with the music itself, of course :-) ).
Expensive studio mics reproduce the full range 20-20,000 Hz and leave it to the sound engineer to filter out high frequencies if necessary. Here's a real studio mic, a Neumann U89, -4 dB at 20 kHz (see PDFs under "Documents"). Good for about $3000. Or, an order of magnitude cheaper, Audio-Technica AT853a.
I sometimes use the latter type for making live recordings of chorus performances on minidisc and apparently, the white-noise background also extends to 20 kHz. It seems that the Atrac-compression (350 kbit/sec) has a hard time with the noise because you don't need golden ears to hear the compression artifacts.
It depends on what you call "very long time". In the centrifuging, you have to beat diffusion by the centrifugal forces. At 5000 RPM in a 10-cm radius, you have an accelleration of 27000 g. That sounds like a lot, but you have to compare the thermal energy kT to the "gravitational" energy gained by moving a molecule over a few cm (about 1e-5 times kT for U235 and 1.01e-5 kT for U238). If you start with 1% U235 and 99% U238, then this centrifuge will give you 1.0000001% versus 89.999999% as the enriched product and 0.9999999% versus 90.0000001% as the enpoored product. Repeat this about 10 million times to get a 50%-enriched product. Of course, you have to re-centrifuge all the "poor" fractions and feed them back into the system, or you will end up with about ten atoms of purified U235, so in fact you must roughly square the number, which means about 1e14 processing steps. I'd call that impossible, not just a matter of patience.
I have once had the opportunity to see the Dutch uranium enrichment plant Urenco from the inside. They enrich up to 5% (reactor-grade uranium) and their centrifuges spin much faster - how fast and what technology they use is top-secret. The result is that they need "only" a couple of ten thousand centrifuges: a large sports hall full of 4-meter-high cylinders.
If there is no propulsion or significant air drag, the acceleration is 9.8 m/s^2 (the gravitational acceleration g) regardless of whether it's going up or down.
This is a silly distinction. The term "white" is defined by what the human eye can see, as you already indicate by mentioning "visible light". Hence, if it looks white to the eye, it is white, by definition.
If I really nitpick, then "white light" does not exist at all, since the sensation of white results from your brain comparing the color sensation from an object to its surroundings. A piece of white paper can emit light with a vastly different spectrum (with vastly different responses in your retina) depending on whether it is illuminated by daylight, incandescent light, or fluorescent-tube light, but it always looks white because of what your brain does.
Or like hiring a webdesign company to build a new web site? :)
The UK used to have 240 V and the mainland 220 V. About 10-15 years ago, it was changed into the average of the two (230 V) such that there is one single standardized voltage in whole Europe. (Never mind that the voltage depends on the distance to the nearest transformer as well)
That's not quite right. Heat dissipation varies quadratically with current:
P = I^2 R
I have many times been amazed at the calculating skills that imperial cooks must have. I've seen recipes that went more or less like this:
And it doesn't get better if you want to increase the amounts by, say, 50%:In the past six years, I have ordered a print at that size only twice. And they were pretty blurry (taken with a mid-range compact camera) if you look at them from close by (what I usually don't do with pictures that hang on the wall).
An expensive camera does not give you good pictures if you don't know how to create a good composition.
Has a nice optical zoom. [...] I think 10X or more.
I hardly ever zoom in all the way on my 3x zoom. The light sensitivity drops and camera shake is amplified, which means blurry pictures unless I use a tripod. More expensive lenses may not drop in light sensitivity, but the problem of camera shake is still there. I'm more bothered by the lack of wide-angles on these cameras, which usually are equivalent to f=38 mm instead of the f=28 mm on my film roll camera.
The biggest plus for me of a 2 MP digital camera is that is small, light, and cheap. I can always carry it without being too worried that it breaks or gets stolen.
Tell me how you did that! I've stubbornly been running fvwm2 up to a few weeks back. The reasons for ditching it were:
- Not cooperating with Qt in Opera 7 (O7 hogs the X server on each focus/unfocus event when invoked under fvwm2)
- It didn't with most gnome tools. It can't read the menu configuration, so you have to guess which programs are available, and if I run some gnome program (was it eyeOfGnome?) I the whole gnome desktop gets started first.
I would be glad to go back to fvwm. I'm stuck with FC1/Gnome/Metacity and it took me damnit half a day to figure out how to customize the start menu and to add an extra menu to the task bar. Adding/customizing menus requires creating a zillion ini-files - one for each menu item and some poking in human-readible-but-not-human-writable XML files.Shred is only for the real paranoid. Recovering overwritten data from a magnetic medium is theoretically possible, but there is no evidence that anyone actually succeeded in doing that in a practical situation. It would require a scanning-tunneling microscope (about $100,000) and the bitrate would (my guess) be in the kbit/s range, so recovering a 40 GB harddisk would take about 1 year, assuming 10 kbit/sec. With this,
oryou will just write zeros and it will be 25 times faster than using shred.Encrypting will make it harder to recover passwords, but the encryption key is still somewhere in the memory. An attacker with root permissions may be able to peek at a live memory image in /proc. I'm not sure where it is nowadays, but in the linux-1.0 days there used to be this huuuge 8 MB file in /proc and otherwise you can always insert a kernel module that does the job. An attacker who is willing to figure out the format of the swap space AND of the user program's data memory won't have a problem with creating a kernel module.
OK, you may be correct here. But up to now it worked pretty well for getting around those Windows-only ISP installation CDs.
And the next generation of zombie programs will do a simple DNS lookup for the mailserver of the current domain and start sending spam through the ISP's mailserver.
With the side effect that in no time no single customer of that ISP can send mail because the mail server is on every blacklist you can imagine.
That won't block the radiation from the cellphone tower. Try wrapping your telephone in aluminum foil, just the small hole that you need to see the signal strength indicator is enough to get 5 bars of signal strength.
I don't think that either the cellphone tower or the power lines will cause lots of interference. As others pointed out, the cellphone is too far away to be of concern. You standing next to the router box phoning to tech support will generate orders of magnitude more interference.
The 50 Hz from the power lines is rather low-frequency and also low intensity. Unlike a cellphone station (10s of watts) or a radio transmitter (many kilowatts), power lines are not designed to emit as much EM radiation as possible. All electronics equipment should be designed to handle a bit of 50-Hz noise or otherwise the equipment would freak out if there is a mains cable lying in the neighbourhood of a data cable.
Almost right... It would be right for a single wire, but here, you have multiple wires, half of them carrying positive voltage and current, and the other half of them a negative voltage and current. These will partially cancel out, giving you 1/r^2 instead of 1/r (for point sources it would be 1/r^3 instead of 1/r^2).
Note that the above is for field strength at distances from the source shorter than the wavelength (6000 km at 50 Hz). For a cellphone tower, with the much shorter wavelengths (10 cm), the intensity drops as 1/r^2, but the field as the square root of that (1/r). Electromagnetic radiation follows rules different from those for (almost-)static fields.
IAAP, too.
Myth. There is no scientific evidence supporting
- that humans need to drink large amounts of water
- that the thirst response of your body has a fundamental misadjustment. (An exception may be extremely intensive sporting, but not normal day-to-day life)
- that impurities are flushed from the body more effectively if you drink more. That is not how the kidneys work.
Drink water or products with a large water content when you feel thirsty. Excessive water intake can lead to loss of minerals.Consume no more than 20 grams of fat (not FAT32) per day
This is a modern belief, especially prevalent in the USA, which is quite disputable. All experts agree in any case that saturated fats and trans-unsaturated fats are unhealthy. However, cis-unsaturated and polyunsaturated fats (roughly the ones that are liquid at room temperature) are not unhealthy per se. Fats are digested much more slowly than carbohydrates, which makes you feel saturated for a longer time after a meal.
Limit alcohol consumption to one occasion per week.
Moderate intake of alcohol has been proven to have a positive effect on heart and blood vessels. The negative effects of alcohol on the liver start only at higher intakes. Moderate here means up to 2 standard glasses (e.g. 100 ml wine or 250 ml beer) per day for males and 1 for females. Essential here is that there is a small amount of alcohol in the body most of the time, so spread out the alcohol intake as much as possible over the days. If you drink red wine, you'll get the additional benefits of the flavonoid anti-oxidants as well.
Of course, it's true that alcohol carries a lot of calories.