14,239 research outputs found
Acetazolamide in the treatment of acute mania - A case report
Several antiepileptic drugs are also being used in affective disorders. There are some hints that also the carbonic anhydrase inhibitor acetazolamide might be useful in the treatment of bipolar affective disorder. We report a 39-year-old male patient with a history of bipolar affective disorder who presented with his second manic episode. Acetazolamide was added to a low dose of valproic acid and to perazine. A marked decrease of the BRMAS score was achieved. The implications of this case are discussed
An RXTE study of M87 and the core of the Virgo cluster
We present hard X-ray observations of the nearby radio galaxy M87 and the
core of the Virgo cluster using the Rossi X-ray Timing Explorer. These are the
first hard X-ray observations of M87 not affected by contamination from the
nearby Seyfert 2 galaxy NGC4388. Thermal emission from Virgo's intracluster
medium is clearly detected and has a spectrum indicative of kT=2.5keV plasma
with approximately 25% cosmic abundances. No non-thermal (power-law) emission
from M87 is detected in the hard X-ray band, with fluctuations in the Cosmic
X-ray Background being the limiting factor. Combining with ROSAT data, we infer
that the X-ray spectrum of the M87 core and jet must be steep (Gamma_core>1.90$
and Gamma_jet>1.75), and we discuss the implications of this result. In
particular, these results are consistent with M87 being a mis-aligned BL-Lac
object.Comment: 8 pages, 2 postscript figures. Accepted for publication in Ap
A Shotgun Model for Gamma Ray Bursts
We propose that gamma ray bursts (GRBs) are produced by a shower of heavy
blobs running into circumstellar material at highly relativistic speeds. The
gamma ray emission is produced in the shocks these bullets drive into the
surrounding medium. The short term variability seen in GRBs is set by the
slowing-down time of the bullets while the overall duration of the burst is set
by the lifetime of the central engine. A requirement of this model is that the
ambient medium be dense, consistent with a strong stellar wind. The efficiency
of the burst can be relatively high.Comment: 4 pages, 2 figures, revised version accepted by ApJ Letter
The Biophysical Perspective of a Middle Income Economy: Material Flows in Mexico
In this paper we analyse natural resource use dynamics in the Mexican economy during the last three decades. Despite low and uneven economic growth, the extraction and use of materials in the Mexican economy has continuously increased over the last 30 years. During this time, population growth, rather than economic growth, has been the main driving force for biophysical growth. In addition, a fundamental change in the primary sectors, in manufacturing as well as in household consumption, has taken place and is reflected in an increasing importance of fossil fuel and construction materials use. Mexico’s economy is strongly influenced by international trade since the country has opened up for competition on international markets. In the 1970s, Mexico’s main export was primary resources. This has changed and manufactured goods now have much greater importance due to a boom in assembling industries. Mexico, unlike other Latin American countries, has achieved a diversification of production moving towards technology intensive products and now has a better mix in its export portfolio. However, crude oil exports still represent the single most important export commodity. Mexico’s material consumption is still well bellow the OECD average but is growing fast and the current resource use patterns may well present serious social and environmental problems for the medium and long term sustainability of Mexico’s economy and communities. Information on natural resource use and resource productivity could provide valuable information to guide economic policy planning for Mexico’s future.physical accounting, material flows, resource productivity, Mexico
Elliptic flow of thermal photons and dileptons
In this talk we describe the recently discovered rich phenomenology of
elliptic flow of electromagnetic probes of the hot matter created in
relativistic heavy-ion collisions. Using a hydrodynamic model for the
space-time dynamics of the collision fireball created in Au+Au collisions at
RHIC, we compute the transverse momentum spectra and elliptic flow of thermal
photons and dileptons. These observables are shown to provide differential
windows into various stages of the fireball expansion.Comment: 8 pages, including 9 figures. Invited talk at the Hard Probes 2006
Conference (Asilomar, June 9-16, 2006), to appear in the Proceedings
(Elsevier
Modulation of neural cell membrane conductance by the herbal anxiolytic and antiepileptic drug aswal
To evaluate the effects of aswal on ionic fluxes and neuronal excitation, we performed extracellular and whole cell patch clamp recordings on CA1 pyramidal neurons of guinea pigs and Long-Evans rats. Aswal (100-250 mg/l) was administered systemically, and its effects on the rate of synchronized extracellular field potentials (EFP), membrane parameters, action potentials and postsynaptic potentials were recorded. The extracellular results obtained are consistent with calcium antagonistic properties. Intracellular recordings suggest that a direct sodium antagonistic effect as seen in many antiepileptic drugs plays no significant role. Further effects on ligand gated ion channels are discussed controversially. In summary, the cellular action of aswal appears heterogeneous with calcium antagonism playing a prominent role in counteracting excitation which may be a common feature in epilepsy and different psychiatric conditions as mood and anxiety disorder. Copyright (C) 2000 S. Karger AG, Basel
Optimal Kullback-Leibler Aggregation via Information Bottleneck
In this paper, we present a method for reducing a regular, discrete-time
Markov chain (DTMC) to another DTMC with a given, typically much smaller number
of states. The cost of reduction is defined as the Kullback-Leibler divergence
rate between a projection of the original process through a partition function
and a DTMC on the correspondingly partitioned state space. Finding the reduced
model with minimal cost is computationally expensive, as it requires an
exhaustive search among all state space partitions, and an exact evaluation of
the reduction cost for each candidate partition. Our approach deals with the
latter problem by minimizing an upper bound on the reduction cost instead of
minimizing the exact cost; The proposed upper bound is easy to compute and it
is tight if the original chain is lumpable with respect to the partition. Then,
we express the problem in the form of information bottleneck optimization, and
propose using the agglomerative information bottleneck algorithm for searching
a sub-optimal partition greedily, rather than exhaustively. The theory is
illustrated with examples and one application scenario in the context of
modeling bio-molecular interactions.Comment: 13 pages, 4 figure
Differential treatment of bipolar disorder with old and new antiepileptic drugs
Although lithium remains the preferred medication for bipolar disorders, new investigations suggest that only 60 to 80% of patients have a good response with a classical presentation. The antiepileptics carbamazepine and valproate are important alternatives. Several studies have shown that lithium, carbamazepine and valproate are effective in pure mania. Mixed mania and rapid cycling respond, however, well to valproate. One disadvantage of carbamazepine is its enzyme inducing property with the consequence of a decrease of plasma levels of other psychotropic medications and a worsening of psychopathology. First data indicate a good antimanic and antidepressive efficacy of the new antiepileptic drug lamotrigine
Microdeflectometry - a novel tool to acquire 3D microtopography with nanometer height resolution
We introduce "microdeflectometry", a novel technique for measuring the
microtopography of specular surfaces. The primary data is the local slope of
the surface under test. Measuring the slope instead of the height implies high
information efficiency and extreme sensitivity to local shape irregularities.
The lateral resolution can be better than one micron whereas the resulting
height resolution is in the range of one nanometer. Microdeflectometry can be
supplemented by methods to expand the depth of field, with the potential to
provide quantitative 3D imaging with SEM-like features.Comment: 3 pages, 11 figures, latex, zip-file, accepted for publication at
Optics Letter
Thermalization and Lyapunov Exponents in the Yang-Mills-Higgs Theory
We investigate thermalization processes occurring at different time scales in
the Yang-Mills-Higgs system at high temperatures. We determine the largest
Lyapunov exponent associated with the gauge fields and verify its relation to
the perturbatively calculated damping rate of a static gauge boson.Comment: 33 pages (revtex), 4 PS figures, submitted to PR
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