science
and technology |
oxygen
levels and the great permian extinction
“Not only was atmospheric oxygen content dropping at the end of
the Permian, the scientists said, but carbon dioxide levels were rising,
leading to global climate warming.”
—
“ What's more, in many cases nearby populations of the same species
were cut off from each other because even low-altitude passes had insufficient
oxygen to allow animals to cross from one valley to the next.
“That population fragmentation likely increased the extinction rate
and slowed recovery following the mass extinction, Huey said.”
the web address for the article above is
https://www.abelard.org/news/science0502.php#oxygen_260405 |
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detecting
change in places that other sensors must not go
“Most modern sensors are electronic and work on the principle that
temperature, pressure or stress affects the electrical behaviour of the
sensor. Usually, a computer measures these changes to produce a digital
readout. But electronic sensors can be impractical, unreliable and even
dangerous when used in the wrong conditions. They are unsafe in explosive
environments and many medical applications, and are prone to interference
when used in strong electromagnetic fields, such as in power plants, or
magnetic resonance imaging. Fibre-optic alternatives, which work with light
instead of electricity, have attracted serious interest and are beginning
to monitor data which could never have been measured electronically.”
the web address for the article above is
https://www.abelard.org/news/science0502.php#optic_sensors_120405 |
modelling
evolution and trading skills
“One thing Homo sapiens does that Homo neanderthalensis shows no
sign of having done is trade. The evidence
suggests that such trade was going on even 40,000 years ago. Stone tools
made of non-local materials, and sea-shell jewellery found far from the
coast, are witnesses to long-distance exchanges. That Homo sapiens also
practised division of labour and specialisation is suggested not
only by the skilled nature of his craft work, but also by the fact that
his dwellings had spaces apparently set aside for different uses.
“To see if trade might be enough to account for the dominance of
Homo sapiens, Dr Shogren and his colleagues created a computer model of
population growth that attempts to capture the relevant variables for each
species. These include fertility, mortality rates, hunting efficiency and
the number of skilled and unskilled hunters in each group, as well as levels
of skill in making objects such as weapons, and the ability to specialise
and trade.”
[My emphases.]
related material
human tradition of
killing off the ancestors gathers pace
human classification systems,
using the example of classification of ‘living organisms’ (taxonomy)
the web address for the article above is
https://www.abelard.org/news/science0502.php#neanderthal_100405 |
bio-data
‘security’ - man loses finger to thieves
“A Malaysian businessman has lost a finger to car thieves impatient
to get around his Mercedes' fingerprint security system. Accountant K Kumaran,
the BBC reports, had at first been forced to start the S-class Merc, but
when the carjackers wanted to start it again without having him along, they
chopped off the end of his index finger with a machete.”
It is known bad practice to use bionics as keys, as opposed
to using them for live identification, as at an airport.
the web address for the article above is
https://www.abelard.org/news/science0502.php#finger_thieves_070405 |
| keeping
in touch: black holes a myth [.pdf file]
“Event horizons and closed time-like curves cannot exist in the real
world for the simple reason that they are inconsistent with quantum mechanics.
“[...] it is now possible to describe in some detail what happens
physically when one approaches and crosses a region of space-time where
classical general relativity [GR] predicts there should be an infinite red
shift surface[...].”
—
“The most spectacular examples of solutions to the Einstein equations
where the classical behavior of space-time is inconsistent with the existence
of a universal time are the rotating space-times; the most famous example
being the Godel universe. In these cases universal time fails because the
classical spacetime manifold contains closed time-like curves. Godel thought
that this indicated that there was something wrong with the intuitive notion
of time itself. However we prefer to view this strange behavior as an example
of the failure of classical general relativity on cosmological length scales.
(a view shared by Einstein).”
—
“The new picture that emerges for compact objects is that the interior
space-time of the compact object looks like ordinary space-time except that
the vacuum energy is much larger than the cosmological vacuum energy. There
is no singularity in the interior. The time dilation factor for the interior
metric is positive ( in sharp contrast with the bizarre negative time dilation
factor predicted by classical GR), but approaches zero as one approaches
the event horizon surface. Near the event horizon classical GR breaks down,
and one needs new physics to describe the transition from the interior to
the exterior. From the point of view of GR this transition layer must have
unusual properties in order to support large stresses. However, it appears
that these objects can be mechanically stable.”
the web address for the article above is
https://www.abelard.org/news/science0502.php#black_hole_030405 |
searching
for life on earth 
Straightforward, neatly written short item.
“A hardy robot from Carnegie Mellon has found life in Chile's Atacama
desert; one of the driest and most lifeless places on Earth. Life is barely
detectable over most parts of Atacama, but the rover (named Zoë) was
able to detect lichens and bacterial colonies in two regions that it explored.
The solar-powered rover provides a good example of the kind of technology
that will probably used to search for life on Mars. Next year Zoë will
travel autonomously for two months, travelling 50 km in the search for life.”
—
“ Life is barely detectable over most areas of the Atacama, but the
rover's instruments were able to detect lichens and bacterial colonies in
two areas: a coastal region with a more humid climate and an interior, very
arid region less hospitable to life.
“We saw very clear signals from chlorophyll, DNA and protein. And
we were able to visually identify biological materials from a standard image
captured by the rover," says Waggoner.”
the web address for the article above is
https://www.abelard.org/news/science0502.php#atacama_200305 |
dust
devils clean mars rover?
| 
Dust devils on Mars. Image credit: NASA/JPL
|
 |
“At the Gusev site recently, skies have been very dusty, and on its
421st sol (March 10, 2005) NASA's Mars Exploration Rover
Spirit spied two dust devils in action. This is an image from the rover's
navigation camera.
“Views of the Gusev landing region from orbit show many dark streaks
across the landscape -- tracks where dust devils have removed surface dust
to show relatively darker soil below -- but this is the first time Spirit
has photographed an active dust devil.”
—
“One sol before this image was taken, power output from Spirit's solar
panels went up by about 50 percent when the amount of dust on the panels
decreased. Was this a coincidence, or did a helpful dust devil pass over
Spirit and lift off some of the dust?”
Comments from another
NASA page:
“Energy output from Spirit's solar panels is up as of sol 420, indicating
that some cleaning of dust off of the solar arrays may have occurred naturally.
“As Spirit and Opportunity are the first solar-powered vehicles on
the surface of Mars during the dust storm season, this is a learning experience.
There are likely large transient dust storm events that reduce solar energy
due to dust deposition on the solar arrays and blocking some sunshine, but
also may sometimes raise energy levels by cleaning dust from arrays, possibly
by winds associated with dust storms.”
Also worth looking at is this rolling
sequence of shots from (or of) the two rovers and Mars.
related material
martian rover car-wash
- end note
sol:
- a day of the local planet, in this case Mars. A Mars sol is 24 hours and
37 minutes long.
the web address for the article above is
https://www.abelard.org/news/science0502.php#mars_dustdevil_170305 |
| us
missile shield moves steadily forward
“A missile fired from a U.S. Navy ship off Kauai, Hawaii, intercepted
and destroyed a mock warhead on Thursday, the fifth success in six such
test of the fledgling U.S. anti-missile shield's sea-based leg, the Pentagon
announced.”
—
“The ship fired a Standard Missile (SM)-3 at the target outside the
earth's atmosphere during the descent phase of flight, Lockheed said. Raytheon
Co. is developing the SM-3.
“The Defense Department plans to field up to 30 SM-3 missiles on
Aegis-equipped ships by 2007 to destroy short- and medium-range ballistic
missiles in mid-flight. Other systems are being developed to defend at different
stages.”
—
“Currently deployed on 68 U.S. Navy cruisers and destroyers, the Aegis
system is also being supplied to Spain, Japan, South Korea, Norway and Australia.”
the web address for the article above is
https://www.abelard.org/news/science0502.php#us_missile_shield_260205 |
| when
government and technology meets, screwups are mandatory
“That may not happen in practice. In a trial conducted in December
at Baltimore International Airport, three of the passport readers could
manage to read the chips accurately only 58%, 43% and 31% of the time, according
to confidential figures reported in Card Technology magazine, which covers
the chip-embedded card industry. (An official at America's Department of
Homeland Security confirmed that "there were problems".)
“A second difficulty is the reliability of biometric technology.
Facial-recognition systems work only if the photograph is taken with proper
lighting and an especially bland expression on the face. Even then, the
error rate for facial-recognition software has proved to be as high as 10%
in tests [...]”
And more.....
the web address for the article above is
https://www.abelard.org/news/science0502.php#passport_checks_210205 |
perfect
spiral galaxy - new image
image credit: NASA
“The final instrument on board Swift, the satellite launched in November
last year to hunt for gamma-ray bursts, has been switched on, and the space
lab is now fully operational. The ultra-violet optical telescope (UVOT)
has sent its first picture back to Earth, and is poised to snap its first
gamma-ray burst.
“The false colour image is of the Pinwheel galaxy, M101, regarded
by many as the perfect spiral galaxy. The picture shows hot, star forming
regions on the arms of the galaxy, while the centre is older, and cooler.”
From the NASA
press release, which also has two other images:
“M101 is a bright, face-on, spiral galaxy located in the constellation
Ursa Major (containing the Big Dipper), about 15 million light years from
Earth. These first light images of the M101 galaxy demonstrate that the
UVOT is functioning well in detecting ultraviolet and optical data.”
the web address for the article above is
https://www.abelard.org/news/science0502.php#spiral_galaxy_080205 |
three-part
item on the conflict between privacy and spotting loons
This links to part 3. The other parts are accessible from this page.
Living in the transparent society:
“The idea behind using data mining in counterterrorism is to sort
through a vast sea of information and find the patterns or clues that point
to a terrorist plot - no easy feat. From a political perspective, the problem
is even thornier. We're caught today between a widespread fear that our
privacy is at stake and an equally palpable fear that critical information
may be lost in the flood of data. The larger challenge in counterterrorism
is not simply to try and locate suspicious people. It is to connect the
dots of a terrorist plot in advance without infringing on the privacy of
innocent citizens.”
—
“[...] how to know everything about everyone without knowing anything
about
anyone.”
the web address for the article above is
https://www.abelard.org/news/science0502.php#data_and_terror_050105 |
| is
that expensive flat-screen high-definition tv ready?
“A survey by the UK-based market researcher Screen Digest found that
only half of all plasma TVs on sale in Europe - and none of the cheaper
ones - can display HDTV pictures. And only two of 500 flat-screens on sale
in the US can display the best available HDTV pictures. Information on whether
they can or cannot display HDTV pictures is almost always buried deep in
the sets' technical specifications, and most shops are selling the jumbo
TVs on their screen size and price, not resolution.”
There are suggestions that plasma reliability is still
under question and others suggest that the brightness of LCDs does not satisfy
everyone. New technology called SED is said to be due soon and superior to
the current flat screen methods.
the web address for the article above is
https://www.abelard.org/news/science0502.php#hdtv_040205 |
| possibilities
of advancing natural language translation using ‘google distance’
“To do this, it needs to build a word tree - a database of how words
relate to each other. It might start with any two words to see how they
relate to each other. For example, if it googles "hat" and "head"
together it gets nearly 9 million hits, compared to, say, fewer than half
a million hits for "hat" and "banana". Clearly "hat"
and "head" are more closely related than "hat" and "banana".
“To gauge just how closely, Vitanyi and Cilibrasi have developed
a statistical indicator based on these hit counts that gives a measure of
a logical distance separating a pair of words. They call this the normalised
Google distance, or NGD. The lower the NGD, the more closely the words are
related.”
the web address for the article above is
https://www.abelard.org/news/science0502.php#natural_language_020205 |
