5,933 research outputs found
Capacitors can radiate - some consequences of the two-capacitor problem with radiation
We fill a gap in the arguments of Boykin et al [American Journal of Physics,
Vol 70 No. 4, pp 415-420 (2002)] by not invoking an electric current loop (i.e.
magnetic dipole model) to account for the radiation energy loss, since an
obvious corollary of their results is that the capacitors should radiate
directly even if the connecting wires are shrunk to zero length. That this is
so is shown here by a direct derivation of capacitor radiation using an
oscillating electric dipole radiator model for the capacitors as well as the
alternative less widely known magnetic 'charge' current loop representation for
an electric dipole [see for example "Electromagnetic Waves" by S.A.Schlekunoff,
van Nostrand (1948)]. Implications for Electromagnetic Compliance (EMC) issues
as well as novel antenna designs further motivate the purpose of this paper.Comment: 5 Pages with No figure
HIV infection and domestic smoke exposure, but not human papillomavirus, are risk factors for esophageal squamous cell carcinoma in Zambia: a case-control study
(c) 2015 The Authors. Cancer Medicine published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited
Novel relations and new properties of confluent Heun's functions and their derivatives of arbitrary order
The present article reveals important properties of the confluent Heun's
functions. We derive a set of novel relations for confluent Heun's functions
and their derivatives of arbitrary order. Specific new subclasses of confluent
Heun's functions are introduced and studied. A new alternative derivation of
confluent Heun's polynomials is presented.Comment: 8 pages, no figures, LaTeX file, final versio
Relativistic phase space: dimensional recurrences
We derive recurrence relations between phase space expressions in different
dimensions by confining some of the coordinates to tori or spheres of radius
and taking the limit as . These relations take the form of
mass integrals, associated with extraneous momenta (relative to the lower
dimension), and produce the result in the higher dimension.Comment: 13 pages, Latex, to appear in J Phys
Geodesics around Weyl-Bach's Ring Solution
We explore some of the gravitational features of a uniform ring both in the
Newtonian potential theory and in General Relativity. We use a spacetime
associated to a Weyl static solution of the vacuum Einstein's equations with
ring like singularity. The Newtonian motion for a test particle in the
gravitational field of the ring is studied and compared with the corresponding
geodesic motion in the given spacetime. We have found a relativistic peculiar
attraction: free falling particle geodesics are lead to the inner rim but never
hit the ring.Comment: 8 figures, 14 pages. LaTeX w/ subfigure, graphic
Fuels treatment and wildfire effects on runoff from Sierra Nevada mixed-conifer forests
We applied an eco-hydrologic model (Regional Hydro-Ecologic Simulation System [RHESSys]), constrained with spatially distributed field measurements, to assess the impacts of forest-fuel treatments and wildfire on hydrologic fluxes in two Sierra Nevada firesheds. Strategically placed fuels treatments were implemented during 2011–2012 in the upper American River in the central Sierra Nevada (43 km2) and in the upper Fresno River in the southern Sierra Nevada (24 km2). This study used the measured vegetation changes from mechanical treatments and modelled vegetation change from wildfire to determine impacts on the water balance. The well-constrained headwater model was transferred to larger catchments based on geologic and hydrologic similarities. Fuels treatments covered 18% of the American and 29% of the Lewis catchment. Averaged over the entire catchment, treatments in the wetter central Sierra Nevada resulted in a relatively light vegetation decrease (8%), leading to a 12% runoff increase, averaged over wet and dry years. Wildfire with and without forest treatments reduced vegetation by 38% and 50% and increased runoff by 55% and 67%, respectively. Treatments in the drier southern Sierra Nevada also reduced the spatially averaged vegetation by 8%, but the runoff response was limited to an increase of less than 3% compared with no treatment. Wildfire following treatments reduced vegetation by 40%, increasing runoff by 13%. Changes to catchment-scale water-balance simulations were more sensitive to canopy cover than to leaf area index, indicating that the pattern as well as amount of vegetation treatment is important to hydrologic response
Minimal coupling method and the dissipative scalar field theory
Quantum field theory of a damped vibrating string as the simplest dissipative
scalar field investigated by its coupling with an infinit number of
Klein-Gordon fields as the environment by introducing a minimal coupling
method. Heisenberg equation containing a dissipative term proportional to
velocity obtained for a special choice of coupling function and quantum
dynamics for such a dissipative system investigated. Some kinematical relations
calculated by tracing out the environment degrees of freedom. The rate of
energy flowing between the system and it's environment obtained.Comment: 15 pages, no figur
Hot Electron Capture Dissociation Distinguishes Leucine from Isoleucine in a Novel Hemoglobin Variant, Hb Askew, β54(D5)Val→Ile
Population migration has led to the global dispersion of human hemoglobinopathies and has precipitated a need for their identification. An effective mass spectrometry-based procedure involves analysis of the intact α- and β-globin chains to determine their mass, followed by location of the variant amino acid residue by direct analysis of the enzymatically digested chains and low-energy collision induced dissociation of the variant peptide. Using this procedure, a variant was identified as either β54Val→Leu or β54Val→Ile, since the amino acids leucine and isoleucine cannot be distinguished using low-energy collisions. Here, we describe how hot electron capture dissociation on a Fourier transform-ion cyclotron resonance mass spectrometer was used to distinguish isoleucine from leucine and identify the mutation as β54(D5)Val→Ile. This is a novel variant, and we have named it Hb Askew
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