|
7 January 2006
Frequency
of meteor impacts on Mars that are violent enough to eject rocks into space:
1 million years.
Amount
of Martian rock that falls to Earth in a typical year:
1 ton.
Scientific
American article
Martian
meteorites
|
|
6 January 2006
Now I become myself. It's taken
Time, many years and places,
I have been dissolved and shaken,
Worn other people's faces,
Run madly, as if Time were there,
Terribly old, crying a warning,
"hurry, you will be dead before -----"
(What? Before you reach the morning?
or the end of the poem is clear?
Or love safe in the walled city?)
Now to stand still, to be here,
Feel my own weight and density!
.....
Now there is time and Time is young.
O, in this single hour I live
All of myself and do not move
I, the pursued, who madly ran,
Stand still, stand still, and stop the Sun!
|
|
5 January 2006
Much
of the progress in molecular biology (and corresponding medical
applications) during recent years has come from asking the question, ‘what
function does this particular gene serve?’
A few years ago, laboratory geneticists happened on a powerful new
tool to ask this question. It’s
called RNA interference, or RNAi for short.
Here’s how it works:
A
gene is a segment of DNA. In
the normal operation of a gene, it acts as a template on which the
components of RNA come together, and form a strand that is a corresponding
RNA copy of the DNA gene. The
RNA strand then breaks loose, and becomes ‘messenger RNA’, or mRNA.
That is, it leaves the nucleus of the cell, and makes its way to a
part of the cell called a ribosome.
The
function of the ribosome is to translate the mRNA into a protein.
Proteins are the workhorses of the body’s chemistry: they can be
inter-cellular signals (hormones) or serve structural functions, or they can
perform any of the myriad metabolic functions that keep an organism humming.
In
RNAi, researchers can silence a particular gene, to see what effect that has
on a particular tissue or an entire organism.
They do this by injecting locally (or globally through an entire
organism) a double-stranded
copy of the particular messenger RNA that corresponds to this gene.
Normally, messenger RNA is a single strand of RNA made from the gene
template. But it turns out that
this double-stranded RNA signals the cell to break up the mRNA before it can
deliver its message (to the ribosome).
How this happens is complicated, but apparently it is an ancient,
evolved mechanism which all higher organisms share. Even though the DNA gene is transcribed into mRNA, the mRNA
degrades before it can do its job. This
gives geneticists the chance to study what happens to the tissue without
this one gene.
Read
more
|
|
4 January 2006
"If there is liberty, if
there is democracy, in this country, it will stand or fall with the right of
the minority to express to the full force of language its opposition in
public to the policies of the government. And it will stand or fall with the
courage of the minority so to express itself. And so I ask you that,
whatever your own judgment of the truth or wisdom of our faith may be, you
will respect it as one of the heroic ideas of humanity’s history. It is either the most
beautiful and courageous mistake that hundreds of millions of mankind ever
made, or else it is really the truth that will lead us out of our misery,
and poverty, and war into a free and happy world. In either case, it
deserves your respect."
~ Max Eastman, born
this day in 1883
In his time, Eastman
shifted seamlessly from poet to journalist, philosopher to agitator, lover
to fighter, radical to conservative. Historically, he stands out merely for
his survival of government persecution during WWI and his revealing to the
world the document now commonly called Lenin's Testament. His editorship of
The Masses and The Liberator, two of the most remarkable journals ever
produced, is enough to ensure his place in literature. And a list of his
friends [Charlie
Chaplin, Ernest Hemingway, Sigmund Freud, Leon Trotsky, H.G. Wells, e.e.
cummings, William F. Buckley, James Joyce…] reads like a Who's Who
of the Century. However, all of this is, if not the tip of the iceberg,
certainly only part of the Max
Eastman story. That he
went from being a major celebrity during his lifetime to a relative unknown
afterward is something for which I don't have all the answers.
- Richard Sautter (who wrote and
performed a one-man play on Eastman’s life)
|
|
3 January 2006
Salamanders, zebrafish,
and other organisms are capable of regenerating new body parts after injury.
Planaria are flatworms a few millimeters long that have the ability to
regenerate an entire new worm from a piece that has been cut off. Alejandro
Alvarado of the Howard Hughes Medical Institute has been studying the
genetics of this phenomenon, and has seen already that much of the basis for
regeneration exists in higher mammals, including man. The ability seems to
be dependent on the presence of stem cells, and activation of a gene he has
dubbed piwi. Meanwhile, Tenneille
Ludwig of the University of Wisconsin reports progress in stimulating
human stem cells to grow in the lab. This research has the potential for
sweeping medical applications, for recovery of tissues lost with age or
accident. Perhaps with the tweaking of a few genes...
|
|
2 January 2006
If I could live again
I would walk barefoot from the beginning of spring
and I would continue barefoot until autumn ends.
I would take more cart rides,
contemplate more dawns,
and play with more children,
If I had another life ahead of me.
~ from Instantes,
written and translated from the Spanish, perhaps by Nadine Stair
"The original is not
faithful to the translation."
- Jorge Luis Borges
I have the fullness of life
ahead of me.
- Josh Mitteldorf
|
|