22,751 research outputs found
Spatial and observational homogeneities of the galaxy distribution in standard cosmologies
This work discusses the possible empirical verification of the geometrical
concept of homogeneity of the standard relativistic cosmology considering its
various definitions of distance. We study the physical consequences of the
distinction between the usual concept of spatial homogeneity (SH), as defined
by the Cosmological Principle, and the concept of observational homogeneity
(OH), arguing that OH is in principle falsifiable by means of astronomical
observations, whereas verifying SH is only possible indirectly. Simulated
counts of cosmological sources are produced by means of a generalized
number-distance expression that can be specialized to produce either the counts
of the Einstein-de Sitter (EdS) cosmology, which has SH by construction, or
other types of counts, which do, or do not, have OH by construction.
Expressions for observational volumes and differential densities are derived
with the various cosmological distance definitions in the EdS model. Simulated
counts that have OH by construction do not always exhibit SH features. The
reverse situation is also true. Besides, simulated counts with no OH features
at low redshift start showing OH characteristics at high redshift. The comoving
distance seems to be the only distance definition where both SH and OH appear
simultaneously. The results show that observations indicating possible lack of
OH do not necessarily falsify the standard Friedmannian cosmology, meaning that
this cosmology will not necessarily always produce observable homogeneous
densities. The general conclusion is that the use of different cosmological
distances in the characterization of the galaxy distribution lead to
significant ambiguities in reaching conclusions about the behavior of the
large-scale galaxy distribution in the Universe.Comment: 12 pages, 12 figures, LaTeX. Matches the final version sent to the
journal. Accepted for publication in "Astronomy and Astrophysics
Potencialidade da cultura do algodão para a produção de biodiesel no Meio-Norte do Brasil.
bitstream/item/83555/1/CT2100001.pd
Estado Confusional Agudo apĂłs Corticoterapia Inalada
Background: The connection between corticotherapy and neuropsychiatric symptoms is
widely known, being one of the first questions
we need to assess when presenting with first
episode psychiatric symptoms or confusional
state.
Aims: To date, data on cases related to inhaled
corticotherapy and neuropsychiatric effects is
scarce. In this paper we describe a rare case in
a young woman.
Methods: The clinical case presented led us
to try to understand the data published on the
subject in order to discuss it in greater length.
Results and Conclusions: We present and
discuss a 27-year-old patient’s case, with no
previous psychiatric disease, who was admitted to our Psychiatric ward after the onset of
severe acute behavioural disturbance characterized by aggressiveness, visual and auditory
hallucinatory activity, misidentification and
altered conscience status. It was later found
that seven days earlier she had been prescribed
inhaled corticotherapy for a minor respiratory
infection. A few days after corticotherapy withdrawal, the clinical symptoms improved significantly.info:eu-repo/semantics/publishedVersio
Tecnologias para a convivencia com o bicudo do algodao.
O objetivo deste trabalho foi disponi ilizar as tecnologias para o controle do bicudo do algodoeiro em uma publicacao de facil acesso aos extensionistas e produtores, visando a melhoria do conhecimento sobre a convivencia com essa praga, e contribuir para o aumento da producao e da produtividade do algodoeiro no estado do Piaui
Comportamento do algodoeiro moco precoce no estado do Piaui.
bitstream/item/96135/1/CT750001.pd
Comportamento do algodoeiro herbaceo na regiao dos cerrados piauienses.
bitstream/item/97545/1/PAND670001.pd
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