2,391 research outputs found
A comparative study for the pair-creation contact process using series expansions
A comparative study between two distinct perturbative series expansions for
the pair-creation contact process is presented. In contrast to the ordinary
contact process, whose supercritical series expansions provide accurate
estimates for its critical behavior, the supercritical approach does not work
properly when applied to the pair-creation process. To circumvent this problem
a procedure is introduced in which one-site creation is added to the
pair-creation. An alternative method is the generation of subcritical series
expansions which works even for the case of the pure pair-creation process.
Differently from the supercritical case, the subcritical series yields
estimates that are compatible with numerical simulations
Total-dose radiation effects data for semiconductor devices. 1985 supplement. Volume 2, part A
Steady-state, total-dose radiation test data, are provided in graphic format for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. This volume provides data on integrated circuits. The data are presented in graphic, tabular, and/or narrative format, depending on the complexity of the integrated circuit. Most tests were done using the JPL or Boeing electron accelerator (Dynamitron) which provides a steady-state 2.5 MeV electron beam. However, some radiation exposures were made with a Cobalt-60 gamma ray source, the results of which should be regarded as only an approximate measure of the radiation damage that would be incurred by an equivalent electron dose
A supercritical series analysis for the generalized contact process with diffusion
We study a model that generalizes the CP with diffusion. An additional
transition is included in the model so that at a particular point of its phase
diagram a crossover from the directed percolation to the compact directed
percolation class will happen. We are particularly interested in the effect of
diffusion on the properties of the crossover between the universality classes.
To address this point, we develop a supercritical series expansion for the
ultimate survival probability and analyse this series using d-log Pad\'e and
partial differential approximants. We also obtain approximate solutions in the
one- and two-site dynamical mean-field approximations. We find evidences that,
at variance to what happens in mean-field approximations, the crossover
exponent remains close to even for quite high diffusion rates, and
therefore the critical line in the neighborhood of the multicritical point
apparently does not reproduce the mean-field result (which leads to )
as the diffusion rate grows without bound
Total-dose radiation effects data for semiconductor devices: 1985 supplement, volume 1
Steady-state, total-dose radiation test data are provided, in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. The document is in two volumes: Volume 1 provides data on diodes, bipolar transistors, field effect transistors, and miscellaneous semiconductor types, and Volume 2 provides total-dose radiation test data on integrated circuits. Volume 1 of this 1985 Supplement contains new total-dose radiation test data generated since the August 1, 1981 release date of the original Volume 1. Publication of Volume 2 of the 1985 Supplement will follow that of Volume 1 by approximately three months
ANALYSIS OF INTERFACIAL AND MASS TRANSFER EFFECTS ON FORCED CONVECTION IN GAS-LIQUID ANNULAR TWO-PHASE FLOW
In a gas-liquid annular two-phase flow one of the main factors influencing
the determination of heat transfer rates is the average thickness of the liquid
film. A model to accurately represent the heat transfer in such situations has
to be able of determining the average liquid film thickness to within a
reasonable accuracy. A typical physical aspect in gas-liquid annular flows is
the appearance of interface waves, which affect heat, mass and momentum
transfers. Existing models implicitly consider the wave effects in the
momentum transfer by an empirical correlation for the interfacial friction
factor. However, this procedure does not point out the difference between
interface waves and the natural turbulent effects of the system. In the
present work, the wave and mass transfer effects in the theoretical
estimation of average liquid film thickness are analyzed, in comparison to a
model that does not explicitly include these effects, as applied to the
prediction of heat transfer rates in a thermally developing flow situation
EFEITOS do Exercício Aeróbio Sobre o Acúmulo de Gordura Visceral em Ratos wistar Submetidos a um Modelo Experimental de Obesidade
Objetivos: Este trabalho teve como objetivo avaliar o efeito do exercício aeróbio crônico sobre o ganho de peso corporal e acúmulo de gordura visceral de ratos criados em prole pequena em comparação com ratos criados em prole normal. Adicionalmente foram também observados parâmetros metabólicos e hemodinâmicos entre estes grupos. Metodologia: Acasalaram-se ratas Wistar virgens aos três meses de idade com ratos da mesma idade/linhagem. No 1º dia de vida das proles os filhotes foram distribuídos aleatoriamente entre as mães. No 3º dia, ajustou-se o tamanho da prole para três filhotes no grupo de superalimentação (GS) ou para 10 filhotes no grupo controle (GC). O peso corporal dos animais foi medido semanalmente. Ao completarem seis semanas de vida, foram selecionados 18 animais do GS e 18 do
GC para realização de exercício aeróbio na esteira, cinco vezes por semana durante nove semanas. A partir de então, denominaram-se os grupos: superalimentação sedentário (SS), controle sedentário (CS), superalimentação exercitado (SE) e controle exercitado (CE). A intensidade das sessões progrediu de 10m/min para 20m/min, a duração aumentou de 10 para 60 minutos e a inclinação foi fixada em 5º
durante todo o treinamento. Na 8ª e 18ª semanas de vida realizou-se um teste de esforço máximo para avaliar a resistência aeróbia. Ao final do período experimental, os animais foram anestesiados e submetidos a uma cirurgia para inserção de cânula de polietileno (PE-50 emendada em PE-10) na artéria femoral para medida direta da pressão arterial e coleta de sangue para dosagens bioquímicas (glicemia, triglicerídeos e HDL-colesterol). Após as medidas os animais foram mortos para
coleta de vísceras e gordura abdominal. Os dados são apresentados como média ± erro padrão.
Resultados: O GS apresentou ganho de peso corporal maior do que o GC a partir da 2ª semana de vida até o fim do experimento (30+0,9g GS contra 23+0,3g GC, P<0,0001, na semana 2 e 524+3,4g GS contra 469+2,9g GC, P<0,001, na semana 17 de vida). No início do treinamento (semana 6 de vida) os ratos sedentários e exercitados não apresentaram diferenças significantes de peso corporal (210+6,7g
SS contra 201+7,8g SE e 188+2,3g CS contra 186+3,3g CE). Da semana 10 até o final do experimento houve diferenças significativas de peso corporal (P<0,05) entre os SS e SE, mas não entre os CS e CE. Não houve diferenças significantes nos parâmetros bioquímicos e hemodinâmicos entre os grupos. Nas comparações de
peso visceral, houve diferenças significativas para peso de ventrículo esquerdo (1,762+0,030mg/g SS contra 1,905+0,040mg/g SE, P<0,01) e de rins (6,10+0,132mg/g SS contra 6,56+0,135mg/g CS; 6,56+0,132mg/g CS contra 7,32+0,226 mg/g CE; e 6,10+0,135mg/g SS contra 6,92+0,187mg/g SE). Os animais do grupo SS apresentaram maior acúmulo de gordura visceral do que os do CS (31,22g+2,08g contra 21,94+1,76g, P<0,05) e o exercício reduziu o depósito de
gordura abdominal nos animais exercitados em comparação com os sedentários (20,08+2,35g SE contra 13,92+2,42g CE, P<0,05).
Conclusão: Ratos criados em prole pequena apresentam maior ganho de peso corporal ao longo do crescimento e parte deste peso adicional deve-se ao acúmulo de gordura abdominal. O exercício aeróbio reduziu o ganho de peso nestes animais, principalmente por diminuir o acúmulo de gordura visceral
A probabilistic approach to emission-line galaxy classification
We invoke a Gaussian mixture model (GMM) to jointly analyse two traditional
emission-line classification schemes of galaxy ionization sources: the
Baldwin-Phillips-Terlevich (BPT) and vs. [NII]/H
(WHAN) diagrams, using spectroscopic data from the Sloan Digital Sky Survey
Data Release 7 and SEAGal/STARLIGHT datasets. We apply a GMM to empirically
define classes of galaxies in a three-dimensional space spanned by the
[OIII]/H, [NII]/H, and EW(H), optical
parameters. The best-fit GMM based on several statistical criteria suggests a
solution around four Gaussian components (GCs), which are capable to explain up
to 97 per cent of the data variance. Using elements of information theory, we
compare each GC to their respective astronomical counterpart. GC1 and GC4 are
associated with star-forming galaxies, suggesting the need to define a new
starburst subgroup. GC2 is associated with BPT's Active Galaxy Nuclei (AGN)
class and WHAN's weak AGN class. GC3 is associated with BPT's composite class
and WHAN's strong AGN class. Conversely, there is no statistical evidence --
based on four GCs -- for the existence of a Seyfert/LINER dichotomy in our
sample. Notwithstanding, the inclusion of an additional GC5 unravels it. The
GC5 appears associated to the LINER and Passive galaxies on the BPT and WHAN
diagrams respectively. Subtleties aside, we demonstrate the potential of our
methodology to recover/unravel different objects inside the wilderness of
astronomical datasets, without lacking the ability to convey physically
interpretable results. The probabilistic classifications from the GMM analysis
are publicly available within the COINtoolbox
(https://cointoolbox.github.io/GMM\_Catalogue/).Comment: Accepted for publication in MNRA
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