Tuesday, February 22, 2011
WAKE n' BACON
http://www.mathlete.com/portfolio/wakeNbacon.php
Thursday, February 10, 2011
Alcohol Does Not Kill Brain Cells
Now, to qualify that title, pure alcohol will absolutely kill brain cells and many other types of cells, which is why it is used as a disinfectant. However, recent research has shown that the quantity of alcohol you could possibly take in, without killing yourself, does not introduce enough alcohol into your bloodstream to kill brain cells. This was proven by a study by Grethe Jensen and co. (1993), who meticulously counted neurons in matched samples of non-alcoholics and alcoholics. What they found was that there was no real difference in the density or overall number of neurons between the two groups. Various other research since has backed up Jensen’s findings. Thus, even alcoholics who are continually taking in unhealthy amounts of alcohol aren’t going to see brain cells die because of their drinking problem. However, alcohol does have other effects on the brain, both positive and negative, that have nothing to do with brain cells dying.
First, the positive: drinking moderate amounts of alcohol on a regular basis has been shown to have various positive effects on your body. The one that pertains to this article’s topic is that it has been shown to help protect people from cognitive impairment as they age. According to a study done at the Catholic University of the Sacred Heart, in Italy, 29% of people 65 years or older who almost never drank alcohol throughout their life had mental impairment issues. On the flip-side of that, only about 19% of people 65 years or older who drank moderate amounts of alcohol regularly had any mental impairment. It was further discovered that, among the various groups where other problems, such as health problems or the like, might impair them mentally, the same trend appeared. In every group, those who drank moderately on a regular basis throughout their lives always had a diminished chance of becoming mentally impaired in their old age compared to those who didn’t drink at all or almost never drank.
Now for the negative (there’s a lot when it comes to intemperate alcohol consumption, so I’ll only cover a few): while brain cells aren’t being killed as the result of drinking excessive amounts of alcohol, the ability for your brain cells to communicate with one another is being inhibited. What’s going on here is that the alcohol ends up damaging dendrites, which are the things at the ends of neurons that conduct electrochemical stimulation from another cell to the cell body in question. Basically, with some of these dendrites damaged, it inhibits the ability of your brain cells to talk to one another.
Luckily, you have an amazing number of connections and neurons in your brain (about 100 billion neurons, along with 10′s of billions of glial cells, which support the neurons). So this helps mask the problem. Also, even among long time alcoholics, it has been shown that simply quitting drinking copious amounts of alcohol is all that is required for your body to be able to reverse most of the damage to the dendrites and restore the ability for your brain cells to communicate. So you can afford to damage some of the neurons temporarily without any real lasting effect.
Unfortunately, for the people who have an extreme habit of excessively drinking, there are other side effects on your brain that aren’t so easily completely fixed, such as developing Wernicke-Korsakoff syndrome, which is characterized by: confusion, coordination problems, hallucinations, memory problems, eye problems, and even inducing a coma or death, if it’s left untreated. What’s going on here is that excessive alcohol consumption over a long period of time causes a vitamin B1 deficiency (8 out of 10 alcoholics are vitamin B1 deficient), due to the alcohol inhibiting the body’s ability to absorb thiamine (also many alcoholics are often malnourished because of their own bad eating habits). This, in turn, causes neuron death, among other things. This is treatable, in most cases, but certain effects stick around forever as your body won’t be able to repair itself completely from this particular brand of damage.
Another brain-related side effect caused by excessive drinking is that high doses of alcohol, while not killing your brain cells, inhibits the growth of new brain cells. However, recent research has shown, at least with rats, that once the alcohol was no longer given to the rats, new brain cell production went into overdrive to try to compensate for the previously inhibited brain cell production. Now, if you go for long enough without giving your brain a chance to recover, drinking excessively on a regular basis, it is thought there may still be lasting effects due to this inhibited new brain cell growth over extended periods, but whether this is actually the case or not, isn’t yet known.
There are also a variety of other known neurological problems that are associated with intemperate alcohol consumptions over long periods of time and some that even show up in a short amount of time in children and teens who abuse alcohol, but this article is already too long. Then of course, there are the myriad of other problems, non-brain related that come with alcoholism, such as liver problems, other nervous system problems outside of how it affects your brain, and others.
Bottom line, alcohol consumed in moderation, such as a small glass of wine a day, can be very good for you. On the other hand, drinking excessively won’t kill you brain cells directly, but is still bad for your brain. Although, your body can compensate, to a certain extent, and repair the damage caused in most cases, at least as far as your brain is concerned, so long as you don’t make a regular habit of it.
Bonus Factoids:
- Another myth concerning alcohol that was once spread about, particularly during Prohibition, but to which I don’t think anyone actually believes anymore (at least I hope not!), is that drinking excessive amounts of alcohol can lead to spontaneous combustion due to alcohol being flammable and it coursing through your veins. This is ridiculous on many levels, but nevertheless, was a popular notion during Prohibition and for a while afterwards. The myth that alcohol kills brain cells was also widely popularized during Prohibition.
- There are several things that contribute to hangovers, but principally what’s going on here is simple dehydration. Alcohol has a dehydrating effect by inhibiting the release of vasopressin, which is an anti-diuretic hormone. So in layman’s terms, the result of alcohol inhibiting the vasopressin is that your body produces a lot more urine than normal with the result that you become dehydrated easily.
- Scientists once believed that the number of nerve cells you have in your brain, once you reach adulthood, was all you’d ever have. Thus, damaging these cells could be extremely detrimental to the individual. However, this isn’t correct. New neurons are created all the time in the adult brain, in a process that is called neurogenesis.
Wednesday, February 9, 2011
Upgrading an IBM/XT to 640k of memory (1985)
The following recipe for upgrading IBM PCs and XTs to 640k of memory on
the motherboard was posted in 1985 by Mike Brown of Nicolet. I did this on
my PC Portable (XT motherboard) and it worked like a charm. It seems like
it's time for a repost ...
--------------------------------------------------------------------------
This document describes how to install 640k of RAM on the system board
in the IBM XT and the IBM portable (which uses the same mother board).
Parts list:
Quantity Description
---------------------------------------------------------------
18 256k by 1 Dynamic RAM chips (any of the following)
Manufacturer Part number
----------------------------------
Fujitsu MB81256-15
Hitachi HM50257-15
Mitsubishi M5M4256-15
NEC uPD41256-15
OKI MSM41256-15
TI TMS4256-15
Toshiba TMM41256-15
1 74LS158 Decoder/multiplexer Integrated circuit
IBM XT Instructions:
1. Turn off the system unit, and disconnect the power cables, monitor and
keyboard cables and any cables that may be connected to expansion boards.
Remove the monitor and the keyboard. Place the system unit in a convenient
work area.
2. Take off the cover from the system unit by removing the 5 screws on the
back (4 corners and top center), slide the cover forward and tip up to
remove completely.
3. Take out any boards installed in the expansion slots by removing the hold
down screw at the rear of the chassis, and pulling the card straight up.
4. The floppy disk drives will have to be removed to gain access to portions
of the mother board. This is done by removing the screws on the left side
of the drive(s). Gently slide the drive(s) out of the unit far enough
to get at the cables plugged into the back of them. Making note of where
each cable goes, remove the data and power cables by gently pulling them
away from the drive. When the cable are off, remove the drive(s) from the
chassis and set them aside.
5. Refer to figure 1 and locate the jumper block labeled E2 on the mother
board. It is located near the edge of the board near the power supply.
6. A jumper has to be installed between pads 1 and 2 on E2. This can be
done without removing the mother board using a short piece of wire. Hold
the wire with a pair of needle nose pliers and heat up one of the pads
with a soldering iron. When the solder melts, push the wire into the pad
and remove the soldering iron. Do the same thing with the other end of
the wire and pad.
7. Refer to figure 1 and locate the IC socket labeled U84 on the mother
board. This will be an empty socket near the front of the board,
underneath where the floppies were mounted. Install the 74LS158 chip in
this socket making sure pin 1 (marked with a dot or notch) is pointing
away from the front panel.
8. Remove the 64k RAM chips in the rows labeled BANK 0 and BANK 1 (9 in each
bank) on the mother board using an IC puller. If you currently only have
128k of memory on the mother board (BANK's 2 and 3 empty) you can move
these chips to those banks. Be careful not to damage the pins when
removing them (you can sell them to a friend whose machine has amnesia).
9. Install the 256k RAM chips in the now empty sockets of BANK 0 and BANK 1
making sure they are installed correctly with pin 1 pointing away from
the front panel. You should now have 2 banks (0 and 1) of 256k RAM chips,
and 2 banks (2 and 3) of 64k RAM chips, giving you a total of 640k.
10. Refer to figure 1 and locate the switch block, SW1 on the mother board.
Make sure that switch positions 3 and 4 are in the OFF position.
11. Re-install the floppy drive(s) by sliding them into the front panel about
half way and reconnect the data and power cables in the same locations
they came off of. Push the drive(s) the rest of the way in and anchor
them with the screws removed earlier.
12. Re-install the your expansion boards (minus any memory boards that used
to be in the system) in the reverse order of when you took them out.
13. Put the cover back on, re-connect the cables and install your monitor and
keyboard.
------------------------------------------------------------------------
EXPANSION
SLOTS
---------------------------------------------
------------------------------------
BANK 0
----
------------------------------------ E
12
------------------------------------ 2
34
BANK 1
--- ----
------------------------------------
S
------------------------------------
W
BANK 2
1
------------------------------------ ---
------------------------------------
BANK 3
---
------------------------------------
U
8
4
---
------------------------------------------------------------------------
Figure 1
(XT/Portable motherboard)
------------------------------------------------------------------------
Tony Movshon
Internet: movshon@nyu.edu
Usenet: movshon@cmcl2.uucp or {ihnp4
allegra}!cmcl2!xp!tony
US Mail: Department of Psychology, NYU
6 Washington Place, room 1083
New York, NY 10003
Phone: (212) 998-7880