1,401 research outputs found
The Symmetry Concept in the Perspective of Basic Education Teachers
The curricular changes that have occurred with the Portuguese Mathematics programme
of study of 2007 showed, among other situations, the introduction of new contents and
the new concept of symmetry. For the teachers, these changes require scientific updates
to be provided so that the outcomes of the mathematics teaching can be guaranteed. In
the academic year 2011/2012 a questionnaire was applied to a 142 inservice basic
education teachers of a particular region of Portugal, to analyze the content knowledge
in this subject (symmetry) and the form of scientific update occurred. The processing of
data allowed us to identify inadequate conceptions, beliefs, topics more or less
successful in responses and also compare the teacher’s responses of the different
teaching groups.info:eu-repo/semantics/publishedVersio
Scalar field description of decaying- cosmologies
The conditions under which cosmologies driven by time varying cosmological
terms can be described by a scalar field coupled to a perfect fluid are
discussed. An algorithm to reconstruct potentials dynamically and
thermodynamically analogue to given phenomenological models is
presented. As a worked example, the deflationary cosmology, which evolves from
a pure de Sitter vacuum state to a slightly modified FRW cosmology is
considered. It is found that this is an example of nonsingular warm inflation
with an asymptotic exponential potential. Differences with respect to other
scalar field descriptions of decaying vacuum cosmologies are addressed and
possible extensions are indicated.Comment: 12 pages, revtex, references added, corrected typos and minor text
change
Transition Redshift: New Kinematic Constraints from Supernovae
The transition redshift (deceleration/acceleration) is discussed by expanding
the deceleration parameter to first order around its present value. A detailed
study is carried out by considering two different parameterizations: and , and the associated free parameters () are constrained by 3 different supernova samples. The previous analysis
by Riess {\it{et al.}} [ApJ 607, 665, 2004] using the first expansion is
slightly improved and confirmed in light of their recent data ({\emph{Gold}}07
sample). However, by fitting the model with the Supernova Legacy Survey (SNLS)
type Ia sample we find that the best fit to the redshift transition is instead of as derived by the High-z Supernovae Search
(HZSNS) team. This result based in the SNLS sample is also in good agreement
with the Davis {\it{et al.}} sample, ().
Such results are in line with some independent analyzes and accommodates more
easily the concordance flat model (CDM). For both parameterizations,
the three SNe type Ia samples considered favor recent acceleration and past
deceleration with a high degree of statistical confidence level. All the
kinematic results presented here depend neither on the validity of general
relativity nor the matter-energy contents of the Universe.Comment: 19 pages, 15 figures, 1 table, revised version accepted for
publication in MNRA
The management of student´s virtual money – sensibilisation and learning for life
The advanced technological age, marketing and society of the abundance in which we live, have a strong influence on the consumption and eating habits of the children. Every day in schools, these little human beings make autonomous choices and their parents, despite seeking to control and know their actions, cannot do it entirely for many reasons. The study was carried out in a group of the fifth grade and their results were subjected to a descriptive and inferential analysis, in which the purpose was to study the relation of some of the variables in question. The conclusions point for example to the parents' lack of knowledge in what concerns the type of consumption and on how their students spend their money. So it can be said that the role of the school in raising responsible citizens in managing their money is a necessary and continuous learning throughout the school life.info:eu-repo/semantics/publishedVersio
Large-scale analysis of the SDSS-III DR8 photometric luminous galaxies angular correlation function
We analyse the large-scale angular correlation function (ACF) of the CMASS
luminous galaxies (LGs), a photometric-redshift catalogue based on the Data
Release 8 (DR8) of the Sloan Digital Sky Survey-III. This catalogue contains
over LGs in the range , which was split
into four redshift shells of constant width. First, we estimate the constraints
on the redshift-space distortion (RSD) parameters and ,
where is the galaxy bias, the growth rate and is the
normalization of the perturbations, finding that they vary appreciably among
different redshift shells, in agreement with previous results using DR7 data.
When assuming constant RSD parameters over the survey redshift range, we obtain
, which agrees at the level with Baryon
Oscillation Spectroscopic Survey DR9 spectroscopic results. Next, we performed
two cosmological analyses, where relevant parameters not fitted were kept fixed
at their fiducial values. In the first analysis, we extracted the baryon
acoustic oscillation peak position for the four redshift shells, and combined
with the sound horizon scale from 7-year \textit{Wilkinson Microwave Anisotropy
Probe} to produce the constraints and
. In the second analysis, we used the ACF full shape
information to constrain cosmology using real data for the first time, finding
and .
These results are in good agreement with findings, showing that the ACF
can be efficiently applied to constrain cosmology in future photometric galaxy
surveys.Comment: MNRAS accepted. Minor corrections to match publish versio
Processo agroindustrial: obtenção de melão desidratado por associação de osmose e secagem em estufa.
O presente trabalho descreve um processo de obtencao de melao desidratado por osmose seguida de secagem em estufa, como uma forma alternativa de aproveitamento e agregacao de valor ao produto.bitstream/CNPAT-2010/8613/1/Ct-095.pd
Influência da cobertura morta no desenvolvimento de fruteiras tropicais.
bitstream/CNPAT-2010/7344/1/Dc-049.pd
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