16,541 research outputs found
Constraints on the Polarization of the Anomalous Microwave Emission in the Perseus Molecular Complex from 7-year WMAP data
We have used the seven year Wilkinson Microwave Anisotropy Probe (WMAP) data
in order to update the measurements of the intensity signal in the G159.6-18.5
region within the Perseus Molecular Complex, and to set constraints on the
polarization level of the anomalous microwave emission in the frequency range
where this emission is dominant. At 23, 33 and 41 GHz, we obtain upper limits
on the fractional linear polarization of 1.0, 1.8 and 2.7% respectively (with a
95 per cent confidence level). These measurements rule out a significant number
of models based on magnetic dipole emission of grains that consist of a simple
domain (Draine & Lazarian 1999) as responsible of the anomalous emission. When
combining our results with the measurement obtained with the COSMOSOMAS
experiment at 11 GHz (Battistelli et al. 2006), we find consistency with the
predictions of the electric dipole and resonance relaxation theory (Lazarian &
Draine 2000) at this frequency range.Comment: 14 pages, 7 figures, ApJ submitte
Variabilidade molecular em genótipos de passiflora edulis sims.
O objetivo deste estudo foi caracterizar acessos não melhorados (GNM) e melhorados (GM) do Banco Ativo de Germoplasma de Maracujazeiro (BAG-Maracujá), além de um híbrido comercial (BRS GA) e 12 em fase de avaliação (HIB) e 19 progênies de meios irmãos (SEDPMI), oriundos do programa de melhoramento genético da Embrapa Mandioca e Fruticultura (PMGM-CNPMF) com o uso de marcadores ISSR (Inter Simple Sequence Repeats). A variação dos genótipos foi avaliada pelo método de agrupamento neighbor joining e por análise de componentes principais. A análise de variância molecular (AMOVA) foi utilizada para verificar a diferenciação entre os grupos de acordo com o grau de melhoramento. Os resultados dos agrupamentos mostraram a formação de dois grupos bem distintos: um proveniente de germoplasma e outro do PMGM-CNPMF. A AMOVA evidenciou que 57% da variação estão entre e 43% dentro dos grupos. Este estudo pode auxiliar na definição de estratégias mais eficientes a serem utilizadas no programa de melhoramento de maracujá amarelo assim como no direcionamento dos cruzamentos entre os genótipos mais contrastantes
Correlation of the South Pole 94 data with 100microns and 408 MHz maps
We present a correlation between the ACME/SP94 CMB anisotropy data at 25 to
45 GHz with the IRAS/DIRBE data and the Haslam 408 MHz data. We find a marginal
correlation between the dust and the Q-band CMB data but none between the CMB
data and the Haslam map. While the amplitude of the correlation with the dust
is larger than that expected from naive models of dust emission it does not
dominate the sky emission.Comment: 6 pages, 4 figures. Accepted for publication in Astronomy and
Astrophysic
Towards a free-free template for CMB foregrounds
A full-sky template map of the Galactic free-free foreground emission
component is increasingly important for high sensitivity CMB experiments. We
use the recently published \ha data of both the northern and southern skies as
the basis for such a template.
The first step is to correct the \ha maps for dust absorption using the 100
m dust maps of Schlegel, Finkbeiner & Davis (1998). We show that for a
range of longitudes, the Galactic latitude distribution of absorption suggests
that it is 33 per cent of the full extragalactic absorption. A reliable
absorption-corrected \ha map can be produced for per cent of the sky;
the area for which a template cannot be recovered is the Galactic plane area
, and some isolated
dense dust clouds at intermediate latitudes.
The second step is to convert the dust-corrected \ha data into a predicted
radio surface brightness. The free-free emission formula is revised to give an
accurate expression (1 per cent) for the radio emission covering the frequency
range 100 MHz to 100 GHz and the electron temperature range 3000 to 20000 K.
The main uncertainty when applying this expression is the variation of electron
temperature across the sky. The emission formula is verified in several
extended H{\sc ii} regions using data in the range 408 to 2326 MHz.
A full-sky free-free template map is presented at 30 GHz; the scaling to
other frequencies is given. The Haslam et al. all-sky 408 MHz map of the sky
can be corrected for this free-free component, which amounts to a
per cent correction at intermediate and high latitudes....Comment: 18 pages, 11 figures, accepted for publication in M.N.R.A.S.
High-resolution versions of figs 2,7 (in colour), 9 and 11 can be obtained
from ftp://ftp.jb.man.ac.uk/pub/cdickins/ff_paper/FINAL_FIGURES
Some properties of two Nambu--Jona-Lasinio -type models with inputs from lattice QCD
We investigate the phase diagram of the so-called
Polyakov--Nambu--Jona-Lasinio (PNJL) model at finite temperature and nonzero
chemical potential. The calculations are performed in the light and strange
quark sectors (, , ), which includes the 't Hooft instanton induced
interaction term that breaks the axial symmetry, and the quarks are coupled to
the (spatially constant) temporal background gauge field. On one hand, a
special attention is payed to the critical end point (CEP). The strength of the
flavor-mixing interaction alters the CEP location, since when it becomes weaker
the CEP moves to low temperatures and can even disappear. On the other hand, we
also explore the connection between QCD, a nonlocal Nambu--Jona-Lasinio type
model and the Landau gauge gluon propagator. Possible links between the
quenched gluon propagator and low energy hadronic phenomenology are
investigated.Comment: Contribution to the International Meeting "Excited QCD", Peniche,
Portugal, 06 - 12 May 201
Transferibilidade de marcadores microssatélites em espécies de Passiflora.
Os marcadores do tipo microssatélites, também conhecidos como SSR (Simple Sequence Repeats) ou SRT (Short Tandem Repeats) são unidades de 1 a 6 nucleotídeos repetidas em tandem. Apresentam um elevado conteúdo de informação de polimorfismo, sendo indicados para identificação e discriminação de genótipos. Como outras vantagens apresentam a co-dominância dos marcadores, alta reprodutividade, rapidez e simplicidade da técnica, baixo custo de utilização e grande poder de resolução (Oliveira et al., 2006). Dentre as dificuldades está o alto custo no desenvolvimento dos iniciadores específicos e na difícil análise de polimorfismos em géis de baixa resolução e com bandas inespecíficas (Faleiro, 2007). Na tentativa de facilitar sua utilização, favorecendo assim as pesquisas, este trabalho teve como objetivo analisar a transferibilidade de iniciadores da espécie Passiflora edulis Sims. (maracujá amarelo) para outras espécies de Passiflora.pdf 89
A determination of the Spectra of Galactic components observed by WMAP
WMAP data when combined with ancillary data on free-free, synchrotron and
dust allow an improved understanding of the spectrum of emission from each of
these components. Here we examine the sky variation at intermediate latitudes
using a cross-correlation technique. In particular, we compare the observed
emission in 15 selected sky regions to three ``standard'' templates.
The free-free emission of the diffuse ionised gas is fitted by a well-known
spectrum at K and Ka band, but the derived emissivity corresponds to a mean
electron temperature of ~4000-5000K. This is inconsistent with estimates from
galactic HII regions. The origin of the discrepancy is unclear.
The anomalous emission associated with dust is clearly detected in most of
the 15 fields studied; it correlates well with the Finkbeiner et al. model 8
predictions (FDS8) at 94 GHz, with an effective spectral index between 20 and
60GHz of -2.85. Furthermore, the emissivity varies by a factor of ~2 from cloud
to cloud. A modestly improved fit to the anomalous dust at K-band is provided
by modulating the template by an estimate of the dust colour temperature,
specifically FDS8*T^n. We find a preferred value n~1.6.
The synchrotron emission steepens between GHz frequencies and the WMAP bands.
There are indications of spectral index variations across the sky but the
current data are not precise enough to accurately quantify this from region to
region. Our analysis of the WMAP data indicates strongly that the
dust-correlated emission at the low WMAP frequencies has a spectrum which is
compatible with spinning dust; we find no evidence for a synchrotron component
correlated with dust (abridged).Comment: 18 pages, 6 figures, revised version uses cross-correlation method
rather than T-T method. Paper re-organised and sent back to refere
Comparação entre folíolo central nos diferentes nós do feijoeiro.
O objetivo do trabalho foi observar se o índice foliar de diferentes nós do talo principal em vários estados de desenvolvimento guarda semelhança entre si
- …