8,010 research outputs found
Autoria na Web 2.0 no contexto da educação e a ética dos hackers.
Este artigo discute a importância do exercício da autoria em ambiente virtual da Web 2.0, considerando que se trata de fundamento essencial à aprendizagem, no professor e no aluno. Autoria na Web 2.0 é apresentada como estratégia pedagógica para ambientes de aprendizagem virtuais, que se utilizam principalmente de ferramentas como blog, wiki e redes sociais. Embora não sejam determinantes essas, tecnologias digitais são condicionantes para que a aprendizagem e a autoria ocorram. Autoria na Web 2.0, além do estabelecimento de novos aparatos tecnológicos, requer novos modos de produção, nos quais prevaleça a postura ética dos hackers, favorecendo a participação, a colaboração, a liberdade e o compartilhamento.Artigo publicado na revista ETD - Educação Temática Digital, Campinas, SP, v. 12, n. esp., p. 154-173, mar. 2011
Image analysis as a tool for viability and recombinant protein production assessment during E. coli fermentations
The development of monitoring methods for physiological state assessment during recombinant
fermentation processes has been encouraged by the need to evaluate the influence of processing
conditions in recombinant protein production.
In this work, microscopy and image analysis techniques were used for the quantification of viability
and protein production in two recombinant E. coli batch fermentations. Images obtained from light
microscopy with phase contrast were used to assess the total number of cells in a given sample and,
from epifluorescence microscopy, both producing and dead cells were counted using two different
filters.
This methodology allowed the extraction of information related to cell viability and recombinant
protein production. This information, combined with standard fermentation data, allowed the
derivation of interesting hypothesis that can be used afterwards for experimental design and further
validation.
Additionally, the ratios calculated in this work can be complemented with other parameters that can be
extracted from image analysis
Experimental determination of the non-extensive entropic parameter
We show how to extract the parameter from experimental data, considering
an inhomogeneous magnetic system composed by many Maxwell-Boltzmann homogeneous
parts, which after integration over the whole system recover the Tsallis
non-extensivity. Analyzing the cluster distribution of
LaSrMnO manganite, obtained through scanning tunnelling
spectroscopy, we measure the parameter and predict the bulk magnetization
with good accuracy. The connection between the Griffiths phase and
non-extensivity is also considered. We conclude that the entropic parameter
embodies information about the dynamics, the key role to describe complex
systems.Comment: Submitted to Phys. Rev. Let
cross section from the dipole model in momentum space
We reproduce the DIS measurements of the proton structure function at high
energy from the dipole model in momentum space. To model the dipole-proton
forward scattering amplitude, we use the knowledge of asymptotic solutions of
the Balitsky-Kovchegov equation, describing high-energy QCD in the presence of
saturation effects. We compare our results with the previous analysis in
coordinate space and discuss possible extensions of our approach.Comment: 9 pages, 3 figure
Wavelets: mathematics and applications
The notion of wavelets is defined. It is briefly described {\it what} are
wavelets, {\it how} to use them, {\it when} we do need them, {\it why} they are
preferred and {\it where} they have been applied. Then one proceeds to the
multiresolution analysis and fast wavelet transform as a standard procedure for
dealing with discrete wavelets. It is shown which specific features of signals
(functions) can be revealed by this analysis, but can not be found by other
methods (e.g., by the Fourier expansion). Finally, some examples of practical
application are given (in particular, to analysis of multiparticle production}.
Rigorous proofs of mathematical statements are omitted, and the reader is
referred to the corresponding literature.Comment: 16 pages, 5 figures, Latex, Phys. Atom. Nuc
Efficiency of informational transfer in regular and complex networks
We analyze the process of informational exchange through complex networks by
measuring network efficiencies. Aiming to study non-clustered systems, we
propose a modification of this measure on the local level. We apply this method
to an extension of the class of small-worlds that includes {\it declustered}
networks, and show that they are locally quite efficient, although their
clustering coefficient is practically zero. Unweighted systems with small-world
and scale-free topologies are shown to be both globally and locally efficient.
Our method is also applied to characterize weighted networks. In particular we
examine the properties of underground transportation systems of Madrid and
Barcelona and reinterpret the results obtained for the Boston subway network.Comment: 10 pages and 9 figure
Fatores de risco associaods com a prevalência sorológica de salmonela em granjas comerciais de suínos do Sul do Brasil.
bitstream/item/85387/1/DCOT-309.pd
Finite-temperature form factors in the free Majorana theory
We study the large distance expansion of correlation functions in the free
massive Majorana theory at finite temperature, alias the Ising field theory at
zero magnetic field on a cylinder. We develop a method that mimics the spectral
decomposition, or form factor expansion, of zero-temperature correlation
functions, introducing the concept of "finite-temperature form factors". Our
techniques are different from those of previous attempts in this subject. We
show that an appropriate analytical continuation of finite-temperature form
factors gives form factors in the quantization scheme on the circle. We show
that finite-temperature form factor expansions are able to reproduce expansions
in form factors on the circle. We calculate finite-temperature form factors of
non-interacting fields (fields that are local with respect to the fundamental
fermion field). We observe that they are given by a mixing of their
zero-temperature form factors and of those of other fields of lower scaling
dimension. We then calculate finite-temperature form factors of order and
disorder fields. For this purpose, we derive the Riemann-Hilbert problem that
completely specifies the set of finite-temperature form factors of general
twist fields (order and disorder fields and their descendants). This
Riemann-Hilbert problem is different from the zero-temperature one, and so are
its solutions. Our results agree with the known form factors on the circle of
order and disorder fields.Comment: 40 pp.; v2: 42 pp., refs and acknowledgment added, typos corrected,
description of general matrix elements corrected and extended; v3: 47 pp.,
appendix adde
Universality classes for rice-pile models
We investigate sandpile models where the updating of unstable columns is done
according to a stochastic rule. We examine the effect of introducing nonlocal
relaxation mechanisms. We find that the models self-organize into critical
states that belong to three different universality classes. The models with
local relaxation rules belong to a known universality class that is
characterized by an avalanche exponent , whereas the models
with nonlocal relaxation rules belong to new universality classes characterized
by exponents and . We discuss the values
of the exponents in terms of scaling relations and a mapping of the sandpile
models to interface models.Comment: 4 pages, including 3 figure
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