407 research outputs found
The Wisconsin H-Alpha Mapper Northern Sky Survey
The Wisconsin H-Alpha Mapper (WHAM) has surveyed the distribution and
kinematics of ionized gas in the Galaxy above declination -30 degrees. The WHAM
Northern Sky Survey (WHAM-NSS) has an angular resolution of one degree and
provides the first absolutely-calibrated, kinematically-resolved map of the
H-Alpha emission from the Warm Ionized Medium (WIM) within ~ +/-100 km/s of the
Local Standard of Rest. Leveraging WHAM's 12 km/s spectral resolution, we have
modeled and removed atmospheric emission and zodiacal absorption features from
each of the 37,565 spectra. The resulting H-Alpha profiles reveal ionized gas
detected in nearly every direction on the sky with a sensitivity of 0.15 R (3
sigma). Complex distributions of ionized gas are revealed in the nearby spiral
arms up to 1-2 kpc away from the Galactic plane. Toward the inner Galaxy, the
WHAM-NSS provides information about the WIM out to the tangent point down to a
few degrees from the plane. Ionized gas is also detected toward many
intermediate velocity clouds at high latitudes. Several new H II regions are
revealed around early B-stars and evolved stellar cores (sdB/O). This work
presents the details of the instrument, the survey, and the data reduction
techniques. The WHAM-NSS is also presented and analyzed for its gross
properties. Finally, some general conclusions are presented about the nature of
the WIM as revealed by the WHAM-NSS.Comment: 42 pages, 14 figures (Fig 6-9 & 14 are full color); accepted for
publication in 2003, ApJ, 149; Original quality figures (as well as data for
the survey) are available at http://www.astro.wisc.edu/wham
Fertilizante de liberação lenta no desenvolvimento de mudas de Eucalyptus grandis.
Uma das ações mais importantes para aumentar a produção de mudas de essências florestais é a fertilização do substrato. A utilização de fertilizante de liberação lenta (FLL) pode contribuir para a obtenção de mudas de melhor qualidade. O objetivo do trabalho foi avaliar doses crescentes de FLL e fertilizante convencional (FC), bem como comparar esses fertilizantes no desenvolvimento de mudas de Eucalyptus grandis. O estudo foi realizado na região do Vale do Itajaí, SC. Os tratamentos foram a adição de FLL e FC para cada experimento nas seguintes doses de formulado: T1 ? 0 kg (testemunha); T2 ? 2 kg; T3 ? 4 kg; T4 ? 6 kg; T5 ? 8 kg e T6 ? 10 kg.m-3 de substrato-base. Decorridos 174 dias da semeadura, foram analisadas as variáveis altura total, diâmetro do colo, biomassa fresca da parte aérea, biomassa seca da parte aérea, biomassa seca da raiz, biomassa seca total, dose de máxima eficiência técnica e teores de nutrientes da parte aérea das mudas de cada tratamento. Em todos os tratamentos houve resposta positiva no desenvolvimento das mudas, entretanto as mudas tiveram melhor crescimento sob doses entre 9,1 e 12,9 kg.m-3 de fertilizante de liberação lenta
Communities as Well Separated Subgraphs With Cohesive Cores: Identification of Core-Periphery Structures in Link Communities
Communities in networks are commonly considered as highly cohesive subgraphs
which are well separated from the rest of the network. However, cohesion and
separation often cannot be maximized at the same time, which is why a
compromise is sought by some methods. When a compromise is not suitable for the
problem to be solved it might be advantageous to separate the two criteria. In
this paper, we explore such an approach by defining communities as well
separated subgraphs which can have one or more cohesive cores surrounded by
peripheries. We apply this idea to link communities and present an algorithm
for constructing hierarchical core-periphery structures in link communities and
first test results.Comment: 12 pages, 2 figures, submitted version of a paper accepted for the
7th International Conference on Complex Networks and Their Applications,
December 11-13, 2018, Cambridge, UK; revised version at
http://141.20.126.227/~qm/papers
H-alpha and Free-Free Emission from the WIM
Recent observations have found the ratio of H-alpha to free-free radio
continuum to be surprisingly high in the diffuse ionized ISM (the so-called
WIM), corresponding to an electron temperature of only ~3000K. Such low
temperatures were unexpected in gas that was presumed to be photoionized. We
consider a 3-component model for the observed diffuse emission, consisting of a
mix of (1) photoionized gas, (2) gas that is recombining and cooling, and (3)
cool H I gas. This model can successfully reproduce the observed intensities of
free-free continuum, H-alpha, and collisionally-excited lines such as NII 6583.
To reproduce the low observed value of free-free to H-alpha, the PAH abundance
in the photoionized regions must be lowered by a factor ~3, and ~20% of the
diffuse H-alpha must be reflected from dust grains, as suggested by Wood &
Reynolds (1999).Comment: 25 pages, 7 figures, 4 tables, single column, details of the
calculation and atomic physics added, accepted by Ap
The permanently chaperone-active small heat shock protein Hsp17 from Caenorhabditis elegans exhibits topological separation of its N-terminal regions
Small Heat shock proteins (sHsps) are a family of molecular chaperones that bind nonnative proteins in an ATP-independent manner. Caenorhabditis elegans encodes 16 different sHsps, among them Hsp17, which is evolutionarily distinct from other sHsps in the nematode. The structure and mechanism of Hsp17 and how these may differ from other sHsps remain unclear. Here, we find that Hsp17 has a distinct expression pattern, structural organization, and chaperone function. Consistent with its presence under nonstress conditions, and in contrast to many other sHsps, we determined that Hsp17 is a mono-disperse, permanently active chaperone in vitro, which interacts with hundreds of different C. elegans proteins under physiological conditions. Additionally, our cryo-EM structure of Hsp17 reveals that in the 24-mer complex, 12 N-terminal regions are involved in its chaperone function. These flexible regions are located on the outside of the spherical oligomer, whereas the other 12 N-terminal regions are engaged in stabilizing interactions in its interior. This allows the same region in Hsp17 to perform different functions depending on the topological context. Taken together, our results reveal structural and functional features that further define the structural basis of permanently active sHsps
Efeito do substrato na produção de mudas de vinhático (Plathymenia reticulata Benth.) - Fabaceae.
Efeito do substrato na produção de mudas de sucupira-preta (Bowdichia virgiloides Kunth) - Fabaceae.
Fertilizaçao de liberação lenta no crescimento de mudas de paricá em viveiro.
A utilização da fertilização de liberação lenta (FLL) pode contribuir para a obtenção de mudas de melhor qualidade, diante de um setor habituado à utilização de fertilizantes comerciais. O objetivo desse trabalho foi avaliar doses de FLL no crescimento de mudas de paricá e a comparar o custo na produção do uso de adubo convencional em relação ao custo com FLL. O delineamento experimental foi inteiramente casualizado com seis tratamentos em quatro repetições de 40 plantas, sendo um controle e os demais com adição de diferentes doses de FLL por m³ de substrato utilizado para a produção de mudas. Decorridos 81 dias da semeadura, foram analisadas as variáveis altura total, diâmetro do colo, biomassa fresca da parte aérea, biomassa seca da parte aérea, biomassa seca da raiz, biomassa seca total e dose de máxima eficiência técnica. As mudas de paricá responderam positivamente ao uso do FLL, apresentando melhores padrões nos parâmetros de interesse em doses variando de 8,65 a 12,07 kg m-3 em relação ao controle sem FLL. Os custos de aquisição foram superiores quando comparados à adubação convencional, sendo necessária uma analise econômica e silvicultural para inferir sobre a viabilidade do seu uso na produção e implantação de plantios
Actinobacillus actinomycetemcomitans lipopolysaccharide induces interleukin-6 expression through multiple mitogen-activated protein kinase pathways in periodontal ligament fibroblasts
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73410/1/j.1399-302X.2006.00314.x.pd
A Hubble Space Telescope WFPC2 Investigation of the Disk-Halo Interface in NGC891
We present deep narrowband observations with high spatial resolution of
extraplanar diffuse ionized gas in the halo of NGC891, obtained with the WFPC2
on-board the HST. Our H-alpha observations, centered on the northern part of
NGC891, reveal an extended gaseous halo, which fills almost the entire field of
view of our WFPC2 observation. The majority of the H-alpha emission is diffuse.
Several discrete features (e.g., filaments) are visible as well. Some of the
filaments reach distances of up to 2.2 kpc above the galactic plane, and are
extremely collimated, even at high galactic latitudes. We compare the
morphology of these filaments with theoretical models, which describe possible
transport mechanisms in a general way. We also investigate extraplanar dust
features, which are best visible in unsharp-masked images of our broadband
F675W image, and we compare them to the spatial distribution of DIG filaments.
Individual dust features, however, are not spatially correlated with diffuse
ionized gas counterparts, such as individual filaments. Quite interestingly,
the orientation of the dust features changes from being mostly aligned
perpendicular to the disk at low galactic latitudes, to a parallel alignment at
high |z|. We compare the diffuse ionized gas distribution to the hot ionized
medium, traced by X-ray observations performed by Chandra. There exists a good
correlation of the presence of the warm and hot ionized gas, in particular, an
X-ray bright region at |z| ~ 1-1.5 kpc fills the entire northern halo region,
whereas the intensity in the midplane is considerably depressed. We also
compare the sizes of individual H-alpha emission line features in the midplane
of NGC891 with similar structures that are known in our Milky Way and in the
LMC.Comment: LaTeX, 15 pages, 11 figures, accepted for publication in The
Astronomical Journal, paper with high resolution figures can be accessed at
http://www.astro.rub.de/jrossa/ngc891
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