3,876 research outputs found
Quantum radiation reaction force on a one-dimensional cavity with two relativistic moving mirrors
We consider a real massless scalar field inside a cavity with two moving
mirrors in a two-dimensional spacetime, satisfying Dirichlet boundary condition
at the instantaneous position of the boundaries, for arbitrary and relativistic
laws of motion. Considering vacuum as the initial field state, we obtain
formulas for the exact value of the energy density of the field and the quantum
force acting on the boundaries, which extend results found in previous papers.
For the particular cases of a cavity with just one moving boundary,
non-relativistic velocities, or in the limit of infinity length of the cavity
(a single mirror), our results coincide with those found in the literature.Comment: 6 pages 9 figure
Neutrino Decay and Neutrinoless Double Beta Decay in a 3-3-1 Model
In this work we show that the implementation of spontaneous breaking of the
lepton number in the 3-3-1 model with right-handed neutrinos gives rise to fast
neutrino decay with majoron emission and generates a bunch of new contributions
to the neutrinoless double beta decay.Comment: Version accepted for publication in the Phys. Rev.
Galactic cold dark matter as a Bose-Einstein condensate of WISPs
We propose here the dark matter content of galaxies as a cold bosonic fluid
composed of Weakly Interacting Slim Particles (WISPs), represented by spin-0
axion-like particles and spin-1 hidden bosons, thermalized in the Bose-Einstein
condensation state and bounded by their self-gravitational potential. We
analyze two zero-momentum configurations: the polar phases in which spin
alignment of two neighbouring particles is anti-parallel and the ferromagnetic
phases in which every particle spin is aligned in the same direction. Using the
mean field approximation we derive the Gross-Pitaevskii equations for both
cases, and, supposing the dark matter to be a polytropic fluid, we describe the
particles density profile as Thomas-Fermi distributions characterized by the
halo radii and in terms of the scattering lengths and mass of each particle. By
comparing this model with data obtained from 42 spiral galaxies and 19 Low
Surface Brightness (LSB) galaxies, we constrain the dark matter particle mass
to the range and we find the lower bound for the
scattering length to be of the order .Comment: 13 pages; 6 figures; references added; v.3: typo corrected in the
abstract, published in JCA
Comparison of 120Sn(6He,6He)120Sn and 120Sn(alpha,alpha)120Sn elastic scattering and signatures of the 6He neutron halo in the optical potential
Cross sections of Sn(,)Sn elastic scattering
have been extracted from the particle beam contamination of a recent
Sn(He,He)Sn experiment. Both reactions are analyzed
using systematic double folding potentials in the real part and smoothly
varying Woods-Saxon potentials in the imaginary part. The potential extracted
from the Sn(He,He)Sn data may be used as the basis for
the construction of a simple global He optical potential. The comparison of
the He and data shows that the halo nature of the He nucleus
leads to a clear signature in the reflexion coefficients : the relevant
angular momenta with and are shifted to
larger with a broader distribution. This signature is not present in the
scattering data and can thus be used as a new criterion for the
definition of a halo nucleus.Comment: 13 pages, 7 figures, accepted for publication in Phys. Rev.
Comment on ``Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions''
We point out that if the majoron-like scheme is implemented within a 331
model, there must exist at least three different mass scales for the scalar
vacuum expectation values in the model.Comment: 4 pages, no figures, Revtex. To be published in Physical Review
Evolutionary relationships in Panicoid grasses based on plastome phylogenomics (Panicoideae; Poaceae)
Background: Panicoideae are the second largest subfamily in Poaceae (grass family), with 212 genera and approximately 3316 species. Previous studies have begun to reveal relationships within the subfamily, but largely lack resolution and/or robust support for certain tribal and subtribal groups. This study aims to resolve these relationships, as well as characterize a putative mitochondrial insert in one linage. Results: 35 newly sequenced Panicoideae plastomes were combined in a phylogenomic study with 37 other species: 15 Panicoideae and 22 from outgroups. A robust Panicoideae topology largely congruent with previous studies was obtained, but with some incongruences with previously reported subtribal relationships. A mitochondrial DNA (mtDNA) to plastid DNA (ptDNA) transfer was discovered in the Paspalum lineage. Conclusions: The phylogenomic analysis returned a topology that largely supports previous studies. Five previously recognized subtribes appear on the topology to be non-monophyletic. Additionally, evidence for mtDNA to ptDNA transfer was identified in both Paspalum fimbriatum and P. dilatatum, and suggests a single rare event that took place in a common progenitor. Finally, the framework from this study can guide larger whole plastome sampling to discern the relationships in Cyperochloeae, Steyermarkochloeae, Gynerieae, and other incertae sedis taxa that are weakly supported or unresolved.Fil: Burke, Sean V.. Northern Illinois University; Estados UnidosFil: Wysocki, William P.. Northern Illinois University; Estados UnidosFil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, FÃsicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Craine, Joseph M.. Jonah Ventures; Estados UnidosFil: Pires, J. Chris. University of Missouri; Estados UnidosFil: Edger, Patrick P.. Michigan State University; Estados UnidosFil: Mayfield Jones, Dustin. Donald Danforth Plant Science Center; Estados UnidosFil: Clark, Lynn G.. Iowa State University; Estados UnidosFil: Kelchner, Scot A.. University of Idaho; Estados UnidosFil: Duvall, Melvin R.. Northern Illinois University; Estados Unido
Mapping quantitative trait loci for performance traits on pig chromosome 6 (SSC6).
The objective of this study was to perform QTL mapping associated with performance traits on swine chromosome 6 (SSC6). The F2 population was produced by outcrossing using two native Brazilian breed Piau sires and 18 commercial dams. A total of 617 F2 animals were genotyped for 13 microsatellite markers. The traits evaluated in the F2 population were teat number (TN), birth weight (BW), weight at 21, 42, 63, 77 and 105 days of age (W21, W42, W63, W77, W105), weight at slaughter (WS), and average daily gain (ADG), feed intake (FI) and feed/gain ratio (FG) from 77 to 105 days of age. Data were analyzed by multiple regression developed for analysis of crosses between outbred lines, using the QTL Express software. A significant QTL was detected for FI at 99 cM. A suggestive QTL was detected for W42 located at 55 cM. A locus located at 100 cM seems to affect the traits FI and ADG. Evidence for loci affecting weight at the other ages not was not found. O objetivo deste estudo foi obter o mapeamento de QTL no cromossomo 6 suÃno (SSC6) associado a caracterÃsticas de desempenho. A população F2 foi produzida utilizando o cruzamento divergente de dois reprodutores da raça nativa brasileira Piau e 18 fêmeas comerciais. Um total de 617 animais F2 foram genotipados para 13 marcadores microssatélites. As caracterÃsticas avaliadas na população F2 foram: número de tetas (TN), peso ao nascimento (BW), peso aos 21, 42, 63, 77 e 105 dias de idade (W21, W42, W63, W77, W105), peso ao abate (WS), e ganho de peso médio diário (ADG), consumo de ração (FI) e conversão alimentar (FG) dos 77 aos 105 dias de idade. Os dados foram analisados usando a metodologia de regressão múltipla desenvolvida para análises de cruzamentos entre linhas divergentes, usando o software QTL Express. Um QTL significativo foi detectado para FI em 99 cM. Um QTL sugestivo foi detectado para W42 localizado em 55cM. As caracterÃsticas FI e ADG parecem estar sob a influência de um loco situado em torno de 100 cM no cromossomo estudado. Não foram encontrados QTLs para peso em as outras diferentes idades
Homeopatia: uma opção de tratamento da mamite bovina
bitstream/item/82580/1/Homeopatia-uma-opcao.pd
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