3,875 research outputs found
Classical study of rotational excitation of a rigid rotor: Li+ plus H2
Classical trajectory study of rotationally inelastic scattering of hydrogen molecules by collisions with lithium ion
Measurement of 139La(p,x) cross sections from 35–60 MeV by stacked-target activation
A stacked-target of natural lanthanum foils (99.9119% 139La) was irradiated using a 60 MeV proton beam at the LBNL 88-Inch Cyclotron. 139La(p,x) cross sections are reported between 35–60 MeV for nine product radionuclides. The primary motivation for this measurement was the need to quantify the production of 134Ce. As a positron-emitting analogue of the promising medical radionuclide 225Ac, 134Ce is desirable for in vivo applications of bio-distribution assays for this emerging radio-pharmaceutical. The results of this measurement were compared to the nuclear model codes TALYS, EMPIRE and ALICE (using default parameters), which showed significant deviation from the measured values
Molecular collisions. 16: Comparison of GPS with classical trajectory calculations of rotational inelasticity for the Ar-N2 system
Comparison of generalized phase shift treatment with classical trajectory calculations of rotational inelasticity cross sections of Ar-N2 scatterin
Quivers with relations arising from Koszul algebras of -invariants
Let be a complex simple Lie algebra and let be an
extremal set of positive roots. One associates with an infinite
dimensional Koszul algebra \bold S_\Psi^{\lie g} which is a graded subalgebra
of the locally finite part of ((\bold V)^{op}\tensor S(\lie g))^{\lie g},
where is the direct sum of all simple finite dimensional \lie
g-modules. We describe the structure of the algebra \bold S_\Psi^{\lie g}
explicitly in terms of an infinite quiver with relations for \lie g of types
and . We also describe several infinite families of quivers and finite
dimensional algebras arising from this construction.Comment: 49 pages, AMSLaTeX+amsref
Because of Science You Also Die... Comment on “Quaternary Prevention, an Answer of Family Doctors to Over Medicalization”
The concept of quaternary prevention (P4) refers to the idea that medicine has acquired the ability to damage
through the proper exercise. Family medicine or general practice has the duty of recovering the ethical values
and the exercise of a profession with the doctor-patient relationship serving to people’s humanity. In the fourth
Congress of Family and Community Medicine, held in Montevideo (Uruguay) last March 18-21, 2015, it was
established the Working Group P4 WONCA-CIMF with communication tools included as constitutive part of
P4. It was also remarked that we should be wary of attempts to denature the P4, diminishing its ethic value and
limiting it to a reason for cost contro
Exponential inequalities for martingales and asymptotic properties of the free energy of directed polymers in random environment
The objective of the present paper is to establish exponential large
deviation inequalities, and to use them to show exponential concentration
inequalities for the free energy of a polymer in general random environment,
its rate of convergence, and an expression of its limit value in terms of those
of some multiplicative cascades.Comment: 25 page
Numerical Evolution of General Relativistic Voids
In this paper, we study the evolution of a relativistic, superhorizon-sized
void embedded in a Friedmann-Robertson-Walker universe. We numerically solve
the spherically symmetric general relativistic equations in comoving,
synchronous coordinates. Initially, the fluid inside the void is taken to be
homogeneous and nonexpanding. In a radiation- dominated universe, we find that
radiation diffuses into the void at approximately the speed of light as a
strong shock---the void collapses. We also find the surprising result that the
cosmic collapse time (the -crossing time) is much smaller than
previously thought, because it depends not only on the radius of the void, but
also on the ratio of the temperature inside the void to that outside. If the
ratio of the initial void radius to the outside Hubble radius is less than the
ratio of the outside temperature to that inside, then the collapse occurs in
less than the outside Hubble time. Thus, superhorizon-sized relativistic void
may thermalize and homogenize relatively quickly. These new simulations revise
the current picture of superhorizon-sized void evolution after first-order
inflation.Comment: 37 pages plus 12 figures (upon request-- [email protected])
LaTeX, FNAL-PUB-93/005-
Tomographic weak lensing shear spectra from large N-body and hydrodynamical simulations
Forthcoming experiments will enable us to determine tomographic shear spectra
at a high precision level. Most predictions about them have until now been
biased on algorithms yielding the expected linear and non-linear spectrum of
density fluctuations. Even when simulations have been used, so-called Halofit
(Smith et al 2003) predictions on fairly large scales have been needed. We wish
to go beyond this limitation. We perform N-body and hydrodynamical simulations
within a sufficiently large cosmological volume to allow a direct connection
between simulations and linear spectra. While covering large length-scales, the
simulation resolution is good enough to allow us to explore the high-l
harmonics of the cosmic shear (up to l ~ 50000), well into the domain where
baryon physics becomes important. We then compare shear spectra in the absence
and in presence of various kinds of baryon physics, such as radiative cooling,
star formation, and supernova feedback in the form of galactic winds. We
distinguish several typical properties of matter fluctuation spectra in the
different simulations and test their impact on shear spectra. We compare our
outputs with those obtainable using approximate expressions for non--linear
spectra, and identify substantial discrepancies even between our results and
those of purely N-body results. Our simulations and the treatment of their
outputs however enable us, for the first time, to obtain shear results taht are
fully independent of any approximate expression, also in the high-l range,
where we need to incorporate a non-linear power spectrum of density
perturbations, and the effects of baryon physics. This will allow us to fully
exploit the cosmological information contained in future high--sensitivity
cosmic shear surveys, exploring the physics of cosmic shears via weak lensing
measurements.Comment: 13 pages, 19 figures, A&A in pres
Optogenetics and deep brain stimulation neurotechnologies
Brain neural network is composed of densely packed, intricately wired neurons whose activity patterns ultimately give rise to every behavior, thought, or emotion that we experience. Over the past decade, a novel neurotechnique, optogenetics that combines light and genetic methods to control or monitor neural activity patterns, has proven to be revolutionary in understanding the functional role of specific neural circuits. We here briefly describe recent advance in optogenetics and compare optogenetics with deep brain stimulation technology that holds the promise for treating many neurological and psychiatric disorders
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