11,758 research outputs found
Random Primordial Magnetic Fields and the Gas Content of Dark Matter Halos
We recently predicted the existence of random primordial magnetic fields
(RPMF) in the form of randomly oriented cells with dipole-like structure with a
cell size and an average magnetic field . Here we investigate models
for primordial magnetic field with a similar web-like structure, and other
geometries, differing perhaps in and . The effect of RPMF on the
formation of the first galaxies is investigated. The filtering mass, , is
the halo mass below which baryon accretion is severely depressed. We show that
these RPMF could influence the formation of galaxies by altering the filtering
mass and the baryon gas fraction of a halo, . The effect is particularly
strong in small galaxies. We find, for example, for a comoving B_0=0.1\muG,
and a reionization epoch that starts at and ends at , for
at , the becomes severely depressed for
M<10^7\msun, whereas for the becomes severely depressed only
for much smaller masses, M<10^5\msun. We suggest that the observation of
and at high redshifts can give information on the intensity and
structure of primordial magnetic fields.Comment: 7 pages, 10 figures, accepted for publication in MNRAS (several
improvements after suggestions of the referee
Produção integrada de maçãs : pragas da macieira e manejo do ácaro Neoseiulus califonicus (Mcgregor) (Phytoseiidae : Acari)
Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Agronomia
Lumbar Spinal Stenosis, Clinical Presentation, Diagnosis, and Treatment
Lumbar spinal stenosis (LSS), a disease that mainly affects people over 50 years old, may have a dramatic presentation with pain, difficulty in walking, changes in urinary functions in addition to root symptoms, such as numbness, burning, and feeling of heaviness in the legs. The treatment is very varied with several non-surgical and surgical possibilities. With an aging population, this disease becomes increasingly preoccupant for their uncertain evolution and without a well-defined correlation with imaging tests, treatment, and outcome may be troublesome. Moreover, LSS frequently affects patients who have associated comorbidity that can hinder the treatment
Playing an educational game featuring procedural content generation: which attributes impact players’ curiosity?
Understanding which and how attributes impact player experience can contribute to designing more tailored tools, providing concerns on how to improve these. However, there is a gap in the understanding of what impacts learners’ experience when interacting with Educational Games (EG) featuring Procedural Content generation (PCG) as these have been scantly used together. This article presents an empirical study on which attributes impact both math’s and game’s curiosity of players when interacting with an EG that uses PCG. The results show the attributes that led to higher or lower curiosity, as well aswhich of them are associated with it. Hence, advancing the understanding of what drives players’ curiosity, contributing to the design of EG that feature PCG
Desempenho de aerogeradores de pequeno porte: simulação do fornecimento de energia elétrica a cargas conectadas à rede pública ou isoladas
The successful in the implementation of wind turbines depends on several factors, including: the wind resource at the installation site, the equipment used, project acquisition and operational costs. In this paper, the production of electricity from two small wind turbines was compared through simulation using the computer software HOMER - a national model of 6kW and an imported one of 5kW. The wind resources in three different cities were considered: Campinas (SP/BR), Cubatão (São Paulo/BR) and Roscoe (Texas/ USA). A wind power system connected to the grid and a wind isolated system - batteries were evaluated. The results showed that the energy cost (/kWh) é fortemente dependente das características do aerogerador e do recurso eólico local. Em relação ao sistema isolado eólico - baterias, a garantia de suprimento integral à carga elétrica simulada só é alcançada com um banco de baterias com muitas unidades e alto número de aerogeradores, devido à intermitência da fonte eólica.36228129
A glimpse on biological activities of tellurium compounds
Tellurium is a rare element which has been regarded as a toxic, non-essential trace element and its biological role is not clearly established to date. Besides of that, the biological effects of elemental tellurium and some of its inorganic and organic derivatives have been studied, leading to a set of interesting and promising applications. As an example, it can be highlighted the uses of alkali-metal tellurites and tellurates in microbiology, the antioxidant effects of organotellurides and diorganoditellurides and the immunomodulatory effects of the non-toxic inorganic tellurane, named AS-101, and the plethora of its uses. Inasmuch, the nascent applications of organic telluranes (organotelluranes) as protease inhibitors and its applications in disease models are the most recent contribution to the scenario of the biological effects and applications of tellurium and its compounds discussed in this manuscript.O telúrio é um elemento não-essencial raro que vem sendo considerado tóxico, e o seu papel biológico é ainda pouco esclarecido. Apesar disso, os efeitos biológicos do telúrio elementar e de alguns derivados inorgânicos e orgânicos que têm sido estudados revelam um conjunto de aplicações diversificadas interessantes e promissoras. Como exemplo, pode-se destacar os usos de teluritos e teluratos de metais alcalinos em microbiologia, o efeito antioxidante de teluretos e diteluretos orgânicos, os efeitos imunomodulatórios e a diversidade de usos correlacionados a este efeito de uma telurana inorgânica denominada AS-101. Ademais, as aplicações de teluranas orgânicas (organoteluranas) como inibidoras de proteases e as aplicações em modelos de doenças compõem a mais recente contribuição ao cenário dos efeitos e aplicações biológicas do telúrio e seus compostos discutidas neste manuscrito.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)UNIFESP Departamento de Ciências Exatas e da TerraUNIFESP Departamento de BiofísicaUNIFESP, Depto. de Ciências Exatas e da TerraUNIFESP, Depto. de BiofísicaSciEL
A physical approach to modelling large-scale galactic magnetic fields
A convenient representation of the structure of the large-scale galactic
magnetic field is required for the interpretation of polarization data in the
sub-mm and radio ranges, in both the Milky Way and external galaxies. We
develop a simple and flexible approach to construct parametrised models of the
large-scale magnetic field of the Milky Way and other disc galaxies, based on
physically justifiable models of magnetic field structure. The resulting models
are designed to be optimised against available observational data.
Representations for the large-scale magnetic fields in the flared disc and
spherical halo of a disc galaxy were obtained in the form of series expansions
whose coefficients can be calculated from observable or theoretically known
galactic properties. The functional basis for the expansions is derived as
eigenfunctions of the mean-field dynamo equation or of the vectorial magnetic
diffusion equation. The solutions presented are axially symmetric but the
approach can be extended straightforwardly to non-axisymmetric cases. The
magnetic fields are solenoidal by construction, can be helical, and are
parametrised in terms of observable properties of the host object, such as the
rotation curve and the shape of the gaseous disc. The magnetic field in the
disc can have a prescribed number of field reversals at any specified radii.
Both the disc and halo magnetic fields can separately have either dipolar or
quadrupolar symmetry. The model is implemented as a publicly available software
package GalMag which allows, in particular, the computation of the synchrotron
emission and Faraday rotation produced by the model's magnetic field. The model
can be used in interpretations of observations of magnetic fields in the Milky
Way and other spiral galaxies, in particular as a prior in Bayesian analyses.
(Abridged.)Comment: 20 pages, 14 figures. Accepted for publication in A&
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