1,234 research outputs found
Total integrated dose testing of solid-state scientific CD4011, CD4013, and CD4060 devices by irradiation with CO-60 gamma rays
The total integrated dose response of three CMOS devices manufactured by Solid State Scientific has been measured using CO-60 gamma rays. Key parameter measurements were made and compared for each device type. The data show that the CD4011, CD4013, and CD4060 produced by this manufacturers should not be used in any environments where radiation levels might exceed 1,000 rad(Si)
The Casimir effect for the scalar and Elko fields in a Lifshitz-like field theory
In this work, we obtain the Casimir energy for the real scalar field and the
Elko neutral spinor field in a field theory at a Lifshitz fixed point (LP). We
analyze the massless and the massive case for both fields using dimensional
regularization. We obtain the Casimir energy in terms of the dimensional
parameter and the LP parameter. Particularizing our result, we can recover the
usual results without LP parameter in (3+1) dimensions presented in the
literature. Moreover, we compute the effects of the LP parameter in the thermal
corrections for the massless scalar field.Comment: 20 pages, 2 figures, some results have been modified and other
changes to the text have been made to match the accepted version in Eur.
Phys. J.
Bound vortex states and exotic lattices in multi-component Bose-Einstein condensates: The role of vortex-vortex interaction
We numerically study the vortex-vortex interaction in multi-component
homogeneous Bose-Einstein condensates within the realm of the Gross-Pitaevskii
theory. We provide strong evidences that pairwise vortex interaction captures
the underlying mechanisms which determine the geometric configuration of the
vortices, such as different lattices in many-vortex states, as well as the
bound vortex states with two (dimer) or three (trimer) vortices. Specifically,
we discuss and apply our theoretical approach to investigate intra- and
inter-component vortex-vortex interactions in two- and three-component
Bose-Einstein condensates, thereby shedding light on the formation of the
exotic vortex configurations. These results correlate with current experimental
efforts in multi-component Bose-Einstein condensates, and the understanding of
the role of vortex interactions in multiband superconductors.Comment: Published in PR
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
Observational constraints on late-time Lambda(t) cosmology
The cosmological constant, i.e., the energy density stored in the true vacuum
state of all existing fields in the Universe, is the simplest and the most
natural possibility to describe the current cosmic acceleration. However,
despite its observational successes, such a possibility exacerbates the well
known cosmological constant problem, requiring a natural explanation for its
small, but nonzero, value. In this paper we study cosmological consequences of
a scenario driven by a varying cosmological term, in which the vacuum energy
density decays linearly with the Hubble parameter. We test the viability of
this scenario and study a possible way to distinguish it from the current
standard cosmological model by using recent observations of type Ia supernova
(Supernova Legacy Survey Collaboration), measurements of the baryonic acoustic
oscillation from the Sloan Digital Sky Survey and the position of the first
peak of the cosmic microwave background angular spectrum from the three-year
Wilkinson Microwave Anisotropy Probe.Comment: Some important revisions. To appear in Physical Review
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
Caracterização de acessos do banco de germoplasma de mamona da Embrapa Algodão.
bitstream/CNPA/19645/1/COMTEC310.pd
Avaliação de condutância estomática e temperatura foliar em variedades de mamão submetidas a déficit hídrico.
A má distribuição das chuvas em algumas regiões torna obrigatório o uso da irrigação nas lavouras comerciais do mamoeiro, pois apesar de ser de clima tropical, a ocorrência de déficit hídrico em períodos de estiagem pode provocar redução da produção e qualidade dos frutos. O déficit hídrico constitui umas das maiores limitações à produtividade vegetal e, desta maneira, ao rendimento das culturas de interesse agronômico. A compreensão dos mecanismos de tolerância das plantas à falta de água é fundamental para uma seleção criteriosa de genótipos tolerantes a esta limitação ambiental, de forma a promover em regiões que apresentam estresse hídrico, a exploração economicamente viável e a obtenção de produtos alimentares com características de qualidade e segurança para o consumidor (EVANS, 1998). Devido ao cenário de mudança climática global, o qual pode causar um aumento da escassez de água, a irrigação e o uso racional desta, ou ainda, o uso de genótipos tolerantes ao déficit hídrico, vêm sendo indicados como importantes objetos de pesquisa no mundo (CHAVES & OLIVEIRA, 2004). Para recomendação de variedades tolerantes, que maximizem a produção com maior economia de água é de grande importância conhecer atributos fisiológicos relacionados com a disponibilidade hídrica no solo. De acordo com Mc Dermit (1990), as plantas, ao absorverem CO2, inevitavelmente, perdem água pelas folhas. Essa perda de água ocorre principalmente através dos estômatos, que apresentam mecanismos para controlar o seu grau de abertura. Esse controle é atribuído à condutância estomática foliar, que é frequentemente utilizada como indicador da deficiência hídrica. A disponibilidade de água afeta o crescimento das plantas, por controlar a abertura dos estômatos e, consequentemente, a produção de fitomassa. A temperatura foliar pode ser usada como indicador do grau de déficit hídrico da planta. Quando o déficit de água no solo provoca o fechamento dos estômatos, a radiação interceptada pela folha tende a promover um aquecimento foliar, podendo chegar a níveis prejudiciais ao metabolismo da planta (TAIZ & ZEIGER, 2004). Por isso, este trabalho teve o objetivo de comparar o comportamento de genótipos de mamoeiro, sob diferentes regimes hídricos, na eficiência do controle das trocas gasosas para tolerância à seca
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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