4,928 research outputs found
Frankenstein: The United States in Afghanistan during the 1980s and 1990s
For nearly the past quarter century, the United States has been involved in covert operations in a region of the world that most people could not locate on a map. Invisible wars being fought by the United States and other foreign intelligence agencies in Afghanistan sowed the seeds for the attacks on September 11, 2001. From the Soviet invasion in 1979 to the summer of 2001, intelligence agencies from around the globe have had a stake in supplying, training, and funding the very same people who carried out those terrible attacks. In the middle of this chaotic time period, Osama bin Laden used political manipulation to devise a plan that would leave a scar on the face of a nation for many years to come. This research will give a history of the U.S. government’s involvement in Afghanistan during the 1980s and 1990s. The Taliban and Al-Qaeda would rise from the ashes of the Soviet conflict to become the new enemy of America. To combat these new faceless adversaries, historians need to look at the mistakes made in the past to prevent similar tragedies in the future
Large 2D Coulomb crystals in a radio frequency surface ion trap
We designed and operated a surface ion trap, with an ion-substrate distance
of 500\mum, realized with standard printed-circuit-board techniques. The trap
has been loaded with up to a few thousand Sr+ ions in the Coulomb-crystal
regime. An analytical model of the pseudo-potential allowed us to determine the
parameters that drive the trap into anisotropic regimes in which we obtain
large (N>150) purely 2D ion Coulomb crystals. These crystals may open a simple
and reliable way to experiments on quantum simulations of large 2D systems.Comment: 4 pages, 4 figure
Photometric identification of the periods of the first candidate extragalactic magnetic massive stars
Galactic stars belonging to the Of?p category are all strongly magnetic
objects exhibiting rotationally modulated spectral and photometric changes on
timescales of weeks to years. Five candidate Of?p stars in the Magellanic
Clouds have been discovered, notably in the context of ongoing surveys of their
massive star populations. Here we describe an investigation of their
photometric behaviour, revealing significant variability in all studied objects
on timescales of one week to more than four years, including clearly periodic
variations for three of them. Their spectral characteristics along with these
photometric changes provide further support for the hypothesis that these are
strongly magnetized O stars, analogous to the Of?p stars in the Galaxy.Comment: 9pages, accepted by A&
Extinction Map of Baade's Window
Recently Wo\'zniak \& Stanek (1996) proposed a new method to investigate
interstellar extinction, based on two band photometry, which uses red clump
stars as a means to construct the reddening curve. I apply this method to the
color-magnitude diagrams obtained by the Optical Gravitational Lensing
Experiment (OGLE) to construct an extinction map of region of
Baade's Window, with resolution of . Such a map should be
useful for studies of this frequently observed region of the Galactic bulge.
The map and software useful for its applications are available via {\tt
anonymous ftp}. The total extinction varies from to
within the field of view centered on (18:03:20.9,--30:02:06), i.e. . The
ratio is determined with this new method.Comment: revised version accepted for publication in ApJ Letters, 8 pages,
uuencoded PostScript with 4 figures included; complete paper available
through WWW at http://www.astro.princeton.edu/~library/prep.html; tables and
auxiliary software available at
ftp://www.astro.princeton.edu/stanek/Extinctio
Fibrinolytic Responses to Moderate Intensity Exercise: Comparison of Physically Active and Inactive Men
The purposes of this study were to compare fibrinolytic responses to moderate intensity exercise in physically active and inactive men and during morning and evening exercise. Fourteen physically inactive men (mean age, 34.7 ± 4.0 years) and 12 regularly active men (34.8 ± 4.0 years) performed two exercise sessions, morning and evening, at 50% of maximal oxygen consumption. Tissue plasminogen activator (TPA) andplasminogen activator inhibitor-1 (PAI-1) activity were measured before and after exercise. Data were analyzed using a three-way ANOVA with repeated measures. TPA actively increased with exercise in both groups, although the active group demonstrated greater increases than the inactive group. Postexercise TPA activity was greater with evening than morning exercise. The inactive group exhibited greater PAI-1 activity than the active group. PAI-1 activity was higher during the morning than evening but did not change with exercise for either group. We conclude that moderate intensity exercise increases TPA activity in physically active and inactive men, with greater increases seen in active men, particularly during evening exercise. Moderate intensity exercise does not appear to affect PAI-1 activity. The lower PAI-1 activity in men may be one mechanism whereby regular physical activity lowers the risk of coronary artery disease
The Zero Point of Extinction Toward Baade's Window
We measure the zero point of the Stanek (1996) extinction map by comparing
the observed (V-K) colors of 206 K giant stars with their intrinsic (V-K)_0
colors as derived from their H\beta indices. We find that the zero point of the
Stanek map should be changed by \Delta A_V = -0.10 +/- 0.06 mag, obtaining as a
bonus a three-fold reduction of the previous statistical error. The most direct
way to test for systematic errors in this determination would be to conduct a
parallel measurement based on the (V-K) colors of RR Lyraes (type ab).Comment: 10 pages, 1 figur
SU(2) × SU(2) × U(1) basis for symmetric SO(6) representations : matrix elements of the generators
Matrix elements of the group generators for the symmetric irreducible representations of SO(6) are explicitly calculated in a closed form employing the decomposition chain SO(6) ⊃ SU(2) x SU(2) x U(1) (which is different from the well known Wigner supermultiplet scheme). The relation to the Gel'fand Tsetlin method using SO(6) ⊃ SO(5) ⊃ ... ⊃ SO(2) is indicated. An example of a physical application is given
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