28,947 research outputs found
Spokes cluster: The search for the quiescent gas
Context. Understanding the role of fragmentation is one of the most important
current questions of star formation. To better understand the process of star
and cluster formation, we need to study in detail the physical structure and
properties of the parental molecular cloud. The Spokes cluster, or NGC 2264 D,
is a rich protostellar cluster where previous N2H+(1-0) observations of its
dense cores presented linewidths consistent with supersonic turbulence.
However, the fragmentation of the most massive of these cores appears to have a
scale length consistent with that of the thermal Jeans length, suggesting that
turbulence was not dominant. Aims. These two results probe different density
regimes. Our aim is to determine if there is subsonic or less-turbulent gas
(than previously reported) in the Spokes cluster at higher densities. Methods.
We present APEX N2H+(3-2) and N2D+(3-2) observations of the NGC2264-D region to
measure the linewidths and the deuteration fraction of the higher density gas.
The critical densities of the selected transitions are more than an order of
magnitude higher than that of N2H+(1-0). Results. We find that the N2H+(3-2)
and N2D+(3-2) emission present significantly narrower linewidths than the
emission from N2H+(1-0) for most cores. In two of the spectra, the nonthermal
component is close (within 1-sigma) to the sound speed. In addition, we find
that the three spatially segregated cores, for which no protostar had been
confirmed show the highest levels of deuteration. Conclusions. These results
show that the higher density gas, probed with N2H+ and N2D+(3-2), reveals more
quiescent gas in the Spokes cluster than previously reported. More high-angular
resolution interferometric observations using high-density tracers are needed
to truly assess the kinematics and substructure within NGC2264-D. (Abridged)Comment: 8 pages, 4 figures. Accepted in A&
Sensitivity to SUSY Seesaw Parameters and Lepton Flavour Violation
We address the constraints on the SUSY seesaw parameters arising from Lepton
Flavour Violation observables. Working in the Constrained Minimal
Supersymmetric Standard Model extended by three right-handed (s)neutrinos, we
study the predictions for the branching ratios of and channels. We impose compatibility with neutrino data, electric
dipole moment bounds, and further require a successful baryon asymmetry of the
Universe (via thermal leptogenesis). We emphasise the interesting interplay
between and the LFV muon decays, pointing out the hints on the
SUSY seesaw parameters that can arise from measurements of and
LFV branching ratios. This is a brief summary of the work of Ref.
\cite{Antusch:2006vw}.Comment: 6 pages, 4 figures. Presented at 5th Flavor Physics and CP Violation
Conference (FPCP 2007), Bled, Slovenia, 12-16 May 200
Atomic jet from SMM1 (FIRS1) in Serpens uncovers non-coeval binary companion
We report on the detection of an atomic jet associated with the protostellar
source SMM1 (FIRS1) in Serpens. The jet is revealed in [FeII] and [NeII] line
maps observed with Spitzer/IRS, and further confirmed in HiRes IRAC and MIPS
images. It is traced very close to SMM1 and peaks at ~5 arcsec" from the source
at a position angle of $\sim 125 degrees. In contrast, molecular hydrogen
emission becomes prominent at distances > 5" from the protostar and extends at
a position angle of 160 degrees. The morphological differences suggest that the
atomic emission arises from a companion source, lying in the foreground of the
envelope surrounding the embedded protostar SMM1. In addition the molecular and
atomic Spitzer maps disentangle the large scale CO (3-2) emission observed in
the region into two distinct bipolar outflows, giving further support to a
proto-binary source setup. Analysis at the peaks of the [FeII] jet show that
emission arises from warm and dense gas (T ~1000 K, n(electron) 10^5 - 10^6
cm^-3). The mass flux of the jet derived independently for the [FeII] and
[NeII] lines is 10^7 M(sun)/yr, pointing to a more evolved Class~I/II protostar
as the driving source. All existing evidence converge to the conclusion that
SMM1 is a non-coeval proto-binary source.Comment: 10 pages, 7 figures, 1 table. Accepted for publication in Astronomy
\& Astrophysic
Description and molecular phylogeny of a new and one known needle nematode of the genus Paralongidorus (Nematoda: Longidoridae) from grapevine in Portugal
A new and a known longidorid nematode, Paralongidorus lusitanicus n. sp. and Paralongidorus plesioepimikis, are described and illustrated from populations extracted from soil associated with grapevine (Vitis vinifera L.) from Escaroupim and Pó (central-Western Portugal), respectively. The new needle nematode P. lusitanicus n. sp. is characterised by a very large body size (8072–12,022 μm), an expanded and rounded lip region, ca 30 μm wide, with a clear constriction followed by a depression posterior to the amphidial aperture, amphidial fovea very large (11.0–19.0 μm), stirrup-shaped, with conspicuous slit-like aperture as shown in scanning electron microscopy studies, a very long and flexible odontostyle (180.0–223.0 μm), guiding ring located at 28.0–41.5 μm from anterior end, vulva anterior to the mid-body (34–41%), a dorsally convex-conoid tail with rounded terminus (29–42 μm long), bearing two or three pairs of caudal pores and males common (ratio 1:1.6 females) with spicules ca 80 μm long. Morphological and morphometric traits for P. plesioepimikis fit well with the original description, and is reported for the first time in Portugal. Integrative diagnosis of both species was completed with molecular data obtained using D2-D3 expansion segments of 28S rDNA, ITS1-rDNA and partial 18S–rDNA. The phylogenetic relationships of these species with other Paralongidorus spp. using these three molecular markers indicated that P. lusitanicus n. sp. clustered together with other Paralongidorus spp. forming a sister clade with P. plesioepimikis, both of them sharing a large body, long odontostyle, an anteriorly located vulva and an expanded and rounded lip region with a clear constriction followed by a depression posterior to the amphidial aperture
Condicionantes da adoção da tecnologia de despolpamento na cafeicultura.
Os cafeicultores de Venda Nova do Imigrante, ES, que, em sua maioria, são Agricultores familiares, têm adotado novas tecnologias para melhorar a qualidade do café arábica produzido na região. O objetivo deste trabalho é identificar os fatores que determinam a adoção, por parte dos referidos cafeicultores, da tecnologia de despolpamento. O modelo Logit é aqui utilizado como instrumento metodológico. Conforme poderá ser observado nos resultados apresentados pelo estudo, os aspectos relativos a associativismo, a escolaridade, a capital próprio, a produtividade, a rentabilidade e a treinamento determinam a adoção da tecnologia de despolpamento; e as variáveis que mais contribuem para a adoção de tal tecnologia são: rentabilidade, associativismo e treinamento
Transferência de conhecimento da formação para o local de trabalho: um estudo de caso misto exploratório
Dissertação de mestrado integrado em PsicologiaO presente estudo tem por objetivo explorar os fatores que estão envolvidos na
transferência de conhecimento da formação para o local de trabalho. Foi realizado no
departamento de desenvolvimento de uma multinacional da área da indústria. De forma a
explorar estes fatores foram elaborados focus groups, análise de documentos e a aplicação
do questionário PLTSI, construído por Holton e validado para a população portuguesa por
Velada. Neste estudo conseguiu-se analisar o dinamismo do modelo de Holton e confirmar
uma das maiores críticas ao modelo: a não análise das interações de fatores do mesmo tipo.
Considerando-se ser necessário estudos futuros nesta área.The present study goal is to explore the factors underlying Knowledge transfer from
training to the workplace. It take place in the development department of multinational in
the industry area. In order to explore this factors has been made focus groups, document
analyses and application of PLTSI questionnaire. This questionnaire was built by Holton
and validated to Portuguese population by Velada. This study was able to analyze the
dynamism of Holton’s model and confirm one of is biggest critics: it does not analyze the
interaction between the same type factors. There is a need of more studies in this area
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