530 research outputs found
Multi-sensor analysis of extreme events in North-Eastern Italy
International audienceThe North-eastern part of Italy is known to be one of the most rainy regions in Europe. In this paper three extreme events are analysed, using a multi-sensor observing system including a weather radar and a dense telemetric network of surface stations, recording precipitation, wind, temperature and relative humidity. The cases examined comprise two long lasting rainfall events impacting two distinct areas, and a vigorous hail-producing thunderstorm event over the plains. In all cases, inter-comparison between remotely sensed and surface observations, including estimates and measures of precipitation and wind, helps to better understand the behaviour of the atmosphere, thus supporting operational fore- and now-casting. In the case of widespread precipitation, a relation is suggested between the wind speed and direction at medium/low levels with the location of the maximum precipitation relative to the mountains. This reflects the dynamical interaction between the mountain barrier and the atmospheric flux impinging upon it. This flux can be estimated by the automatic weather station of Mt. Cesen, a focal point for a now-casting of the rain in the Veneto Region. Analysis of strong thunderstorm activity makes extensive use of radar data. In the examined case the interaction of a sea breeze-like circulation with a mesoscale trough gave rise to a distinct convergence line that triggered a severe and long-lived hail-producing multi-cell thunderstorm. The hail was successfully detected by the radar's hail detection algorithm
Análisis filogenético de aislamientos de Groundnut ringspot virus desde maní e identificación de posibles trips vectores asociados al cultivo de maní en la Argentina
Groundnut ringspot virus (GRSV), genus Tospovirus, is a thrips-transmitted virus infecting peanuts (Arachis hypogaea L.) in Córdoba province, Argentina. Fourteen viral isolates were recovered from Tospovirus-like symptomatic plants from different peanut fields. Viral isolates as GRSV were identified by serological and molecular tests. Nucleotide and derived amino acid sequence analyses of the nucleocapsid (N) gene indicated a high degree of identity between the GRSV peanut isolates, indicating that there is no molecular variability in the N gene of the GRSV that infects peanuts in the cropping area of Córdoba. In this study, we determined the presence of thrips species in the crop, which can potentially transmit the virus. Thrips were observed in all the evaluated peanut fields. Frankliniella schultzei was the most frequently identified species followed by Caliothrips phaseoli and Frankliniella occidentalis. This work reports the presence of F. schultzei and F. occidentalis in peanuts in Argentina for the first time. These results along with the high degree of similarity between the GRSV peanut isolates suggest that the virus could be transmitted by F. schultzei, which has been cited as its most efficient vector.Groundnut ringspot virus (GRSV, género Tospovirus) es un virus que infecta naturalmente el cultivo de maní (Arachis hypogaea L.) en la región productora de Córdoba, Argentina. En distintas localidades de la provincia, se colectaron 14 aislamientos virales provenientes de maníes que manifestaban síntomas característicos de Tospovirus. Todos los aislamientos virales fueron identificados como GRSV mediante pruebas serológicas y moleculares. El análisis de las secuencias nucleotídicas y de amino ácidos deducidas del gen de la nucleoproteína (N) reveló un alto grado de identidad entre los 14 aislamientos, indicando que no existe variabilidad molecular en el gen N del GRSV que infecta maní en la provincia de Córdoba. En este estudio se determinó la presencia de trips en el cultivo que pueden potencialmente transmitir la enfermedad. Estos insectos fueron observados colonizando maní en todos los lotes evaluados. La especie identificada con mayor frecuencia fue Frankliniella schultzei, seguida de Caliothrips phaseoli y Frankliniella occidentalis. Este es el primer reporte de F. schultzei y F. occidentalis afectando maní en Argentina. Estos resultados, junto con el elevado grado de similitud encontrado entre los distintos aislamientos de GRSV, sugieren que el virus puede ser transmitido por F. schultzei, citado como el vector más eficiente del GRSV
Churg-Strauss syndrome: outcome and long-term follow-up of 38 patients from a single Italian centre
Objective: This study was aimed at verifying any potential correlation between anti-myeloperoxidase antineutrophil cytoplasmic antibodies (ANCA-MPO) and clinical features and outcome indices in Churg-Strauss Syndrome (CSS). Methods: Thirhty-eight Churg-Strauss syndrome patients were selected from the medical records of all vasculitis patients attending the Rheumatology and Immunology Unit at the Department of Internal Medicine of the University of Pisa in the decades between 1989 and 2008. Data were analysed retrospectively. Statistical analyses of the results were carried out using the Mann-Whitney test to determine the correlations between the clinical and serological parameters. Qualitative variables were compared using contingency table analysis and Fisher's exact test. Results: ANCA-MPO were detected in15/38 (39%) patients. Positive ANCA status was associated with peripheral neuropathy (p=0.0006), whereas negative ANCA status was associated with lung involvement (p=0.002). Relapses were strongly associated with positive ANCA status (p=0.01) and with an increase in- or a reappearence of ANCA-MPO levels (p=0.006). Finally, ANCA-MPO were significantly associated with neurological damage (p=0.003). Conclusions: The presence or absence of ANCA-MPO identify different clinical subsets in CSS. Overall, ANCA-MPO appears as a useful tool in the monitoring of CSS and in particular a good predictor of CSS relapse
H-alpha Survey of the Local Volume: Isolated Southern Galaxies
We present our H-alpha observations of 11 isolated southern galaxies: SDIG,
PGC 51659, E 222-010, E 272-025, E 137-018, IC 4662, Sag DIG, IC 5052, IC 5152,
UGCA 438, and E149-003, with distances from 1 to 7 Mpc. We have determined the
total H-alpha fluxes from these galaxies. The star formation rates in these
galaxies range from 10^{-1} (IC 4662) to 10^{-4}_{\odot}/yr (SDIG) and the gas
depletion time at the observed star formation rates lies within the range from
1/6 to 24 Hubble times H_0^{-1} .Comment: 9 pages, 3 figure
A theoretical analysis of complex armed conflicts
The introduction and analysis of a simple idealized model enables basic insights into how military characteristics and recruitment strategies affect the dynamics of armed conflicts, even in the complex case of three or more fighting groups. In particular, the model shows when never ending wars (stalemates) are possible and how initial conditions and interventions influence a conflict’s fate. The analysis points out that defensive recruitment policies aimed at compensating for suffered losses lead to conflicts with simple dynamics, while attack groups sensitive to the damages they inflict onto their enemies can give rise to conflicts with turbulent behaviours. Since non-governmental groups often follow attack strategies, the conclusion is that the evolution of conflicts involving groups of that kind can be expected to be difficult to forecast
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
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
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