1,451 research outputs found
CMB Polarization Experiments
We discuss the analysis of polarization experiments with particular emphasis
on those that measure the Stokes parameters on a ring on the sky. We discuss
the ability of these experiments to separate the and contributions to
the polarization signal. The experiment being developed at Wisconsin university
is studied in detail, it will be sensitive to both Stokes parameters and will
concentrate on large scale polarization, scanning a degree ring. We will
also consider another example, an experiment that measures one of the Stokes
parameters in a ring. We find that the small ring experiment will be able
to detect cosmological polarization for some models consistent with the current
temperature anisotropy data, for reasonable integration times. In most
cosmological models large scale polarization is too small to be detected by the
Wisconsin experiment, but because both and are measured, separate
constraints can be set on and polarization.Comment: 27 pages with 12 included figure
Editorial: New Training Strategies and Evaluation Methods for Improving Health and Physical Performance
Physical activity is among the most effective methods for improving health, body composition, and physical function, and its practice is suitable for every population [...]
New Perspective on Galaxy Clustering as a Cosmological Probe: General Relativistic Effects
We present a general relativistic description of galaxy clustering in a FLRW
universe. The observed redshift and position of galaxies are affected by the
matter fluctuations and the gravity waves between the source galaxies and the
observer, and the volume element constructed by using the observables differs
from the physical volume occupied by the observed galaxies. Therefore, the
observed galaxy fluctuation field contains additional contributions arising
from the distortion in observable quantities and these include tensor
contributions as well as numerous scalar contributions. We generalize the
linear bias approximation to relate the observed galaxy fluctuation field to
the underlying matter distribution in a gauge-invariant way. Our full formalism
is essential for the consistency of theoretical predictions. As our first
application, we compute the angular auto correlation of large-scale structure
and its cross correlation with CMB temperature anisotropies. We comment on the
possibility of detecting primordial gravity waves using galaxy clustering and
discuss further applications of our formalism.Comment: 10 pages, 2 figures, accepted for publication in Physical Review
Luminescent Optical Fiber Oxygen Sensor following Layer-by-layer Method
AbstractA sensor based on luminescence has been prepared depositing the luminescent complex platinum tetrakis pentrafluorophenyporphine (PtTFPP) onto a plastic-clad silica (PCS) optical fiber. The sensing film is constructed in terms of Layer-by-Layer method. A LED centered at 400nm was used to interrogate the sensor in a reflection configuration, registering a luminescent signal from the sensing material located at 648nm. The transduction principle is based on the quenching suffered by PtTFPP as the oxygen (O2) concentration increases. The sensor was characterized for O2 concentrations from 0% to 75%, showing a linear Stern–Volmer relationship (R2 = 0.9962)
SAXS study of ion tracks in San Carlos olivine and Durango apatite
Ion tracks were generated in crystalline San Carlos olivine (Mg,Fe) 2SiO 4 and Durango apatite Ca 10(PO 4) 6F 2 using different heavy ions ( 58Ni, 101Ru, 129Xe, 197Au, and 238U) with energies ranging between 185 MeV and 2.6 GeV. The tracks and their annealing behavior were studied by means of synchrotron based small angle X-ray scattering in combination with in situ annealing. Track radii vary as a function of electronic energy loss but are very similar in both minerals. Furthermore, the annealing behavior of the track radii has been investigated and preliminary results reveal a lower recovery rate of the damaged area in olivine compared with apatite
Tomografia sísmica da litosfera continental algarvia
RESUMO: O presente estudo de Tomografia é focado na região do Algarve. Para a localização dos eventos e determinação do modelo de velocidades, são utilizadas as ondas P e S. Os dados foram obtidos entre Janeiro/2006 e Julho/2007. As estimativa dos tempos de origem e coordenadas hipocentrais foram calculadas. A relocalização de eventos e inversão linear respeitaram dois passos: 1) determinação do modelo mínimo 1-D e 2) relocalização dos hipocentros e obtenção da estrutura 3-D em termos de velocidades das ondas P.
ABSTRACT: The present Tomographic study is focused on Algarve region. For event location and velocity model determination P and S waves were used. Data was collected between January/2006 and July/2007. The estimation of origin times and hipocentral determination were calculated. Relocation of events and linear inversion respected two steps: 1) minimum velocity model determination and 2) hipocentral relocation and 3-D Earth structure determination in terms of P wave velocities
A Naturally Large Four-Point Function in Single Field Inflation
Non-Gaussianities of the primordial density perturbations have emerged as a
very powerful possible signal to test the dynamics that drove the period of
inflation. While in general the most sensitive observable is the three-point
function in this paper we show that there are technically natural inflationary
models where the leading source of non-Gaussianity is the four-point function.
Using the recently developed Effective Field Theory of Inflation, we are able
to show that it is possible to impose an approximate parity symmetry and an
approximate continuos shift symmetry on the inflaton fluctuations that allow,
when the dispersion relation is of the form , for a unique
quartic operator, while approximately forbidding all the cubic ones. The
resulting shape for the four-point function is unique. In the models where the
dispersion relation is of the form a similar construction
can be carried out and additional shapes are possible.Comment: 13 pages, 1 figure. v2: extended discussion on near-de-Sitter model
New Sources of Gravitational Waves during Inflation
We point out that detectable inflationary tensor modes can be generated by
particle or string sources produced during inflation, consistently with the
requirements for inflation and constraints from scalar fluctuations. We show
via examples that this effect can dominate over the contribution from quantum
fluctuations of the metric, occurring even when the inflationary potential
energy is too low to produce a comparable signal. Thus a detection of tensor
modes from inflation does not automatically constitute a determination of the
inflationary Hubble scale.Comment: 32 pages, 1 figure. v2: JCAP published version; some overestimates
corrected; main results unchange
Estudo da viabilidade de uma proteção capaz de interagir o medidor portátil de glicose e seus acessórios
O medidor de glicose, em geral dispõe de capa, já fornecida com o equipamento, ou estojo para assegurar a o transporte, contudo as capas não atendem adequadamente a função a qual se destinam. O objeto com a capa assume uma dimensão significativamente maior, comparado quando está sem a capa, além disso, pela característica do material empregado, torna-se sujo pelo constante manuseio, exigindo a lavagem do material. Considerando que os pacientes, em especial os mais jovens, já se sentem, de alguma forma, diferentes pela demanda do uso constante do medidor de glicose, o aspecto estético torna-se importante, podendo até mesmo ser considerado um elemento motivador para uso sem constrangimentos do medidor de glicose. Este estudo pretende desenvolver uma proteção capaz de integrar o medidor de glicose e seus acessórios, considerando todas as requisições consideradas importantes pelos seus usuários, que neste caso serão as crianças, identificadas como tal pelo Estatuto da Criança e do Adolescente no Art. 2º que considera ser criança a pessoa até doze anos de idade incompletos. A inovação da capa de proteção para o aparelho surgiu, a partir da percepção apontada por profissionais da área de saúde que atendem pacientes diabéticos. A Dra. Raquel Barbosa Lima Schwab, especialista em Endocrinologia diz que “[...] muitas das crianças que atendo tem certa resistência ao uso do medidor de glicose, pois o consideram um incômodo. ” A partir deste ponto de vista entende-se ser possível que haja um grande número de pessoas, consideradas crianças, que têm dificuldades relacionadas ao transporte e manuseio do medidor de glicose, por não se sentirem confortáveis com o equipamento. Deste modo, o presente estudo propõe conhecer as demandas dos usuários infantis diabéticos em relação ao uso do equipamento e propor um sistema que qualifique o produto de acordo com os interesses de seus usuários
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