Pathogenicity of a bovine viral diarrhoea virus strain in pregnant sows: Short communication

The biological properties of bovine viral diarrhoea virus (BVDV) strain Oregon C24V were studied after intranasal and subcutaneous infection of pregnant sows. This virus strain is widely used in Hungary for immunising cattle against bovine viral diarrhoea (BVD). Based upon the results of the clinical, gross pathological, histopathological and virological examinations it can be established that the given strain caused asymptomatic infection and serological conversion in sows that were in the second third of gestation. The virus caused clinically apparent disease in some of the piglets born at term, which indicates that it had crossed the placenta. More than half (57%) of the live-born piglets died within 60 days of birth. The sows and their progeny did not shed the virus. BVDV infection has great differential diagnostic importance in pigs, as classical swine fever (CSF) virus strains of reduced virulence cause similar clinical symptoms and gross and histopathological changes

Observations of convective and dynamical instabilities in tropopause folds and their contribution to stratosphere-troposphere exchange

With aircraft-mounted in situ and remote sensing instruments for dynamical, thermal, and chemical measurements we studied two cases of tropopause folding. In both folds we found Kelvin-Helmholtz billows with horizontal wavelength of ∼900 m and thickness of ∼120 m. In one case the instability was effectively mixing the bottomside of the fold, leading to the transfer of stratospheric air into the troposphere. Also, we discovered in both cases small-scale secondary ozone maxima shortly after the aircraft ascended past the topside of the fold that corresponded to regions of convective instability. We interpreted this phenomenon as convectively breaking gravity waves. Therefore we posit that convectively breaking gravity waves acting on tropopause folds must be added to the list of important irreversible mixing mechanisms leading to stratosphere-troposphere exchange.United States. National Aeronautics and Space Administration (Grant NAG2-1105)United States. National Aeronautics and Space Administration (Grant NAGl-1758)United States. National Aeronautics and Space Administration (Grant NAGl-1901

Observationally constrained analysis of sea salt aerosol in the marine atmosphere

Atmospheric sea salt plays important roles in marine cloud formation and atmospheric chemistry. We performed an integrated analysis of NASA GEOS model simulations run with the GOCART aerosol module, in situ measurements from the PALMS and SAGA instruments obtained during the NASA ATom campaign, and aerosol optical depth (AOD) measurements from the AERONET Marine Aerosol Network (MAN) and from MODIS satellite observations to better constrain sea salt in the marine atmosphere. ATom measurements and GEOS model simulations both show that sea salt concentrations over the Pacific and Atlantic oceans have a strong vertical gradient, varying up to 4 orders of magnitude from the marine boundary layer to free troposphere. The modeled residence times suggest that the lifetime of sea salt particles with a dry diameter of less than 3 µm is largely controlled by wet removal, followed by turbulent process. During both boreal summer and winter, the GEOS-simulated sea salt mass mixing ratios agree with SAGA measurements in the marine boundary layer (MBL) and with PALMS measurements above the MBL. However, comparison of AOD from GEOS with AERONET/MAN and MODIS aerosol retrievals indicated that the model underestimated AOD over the oceans where sea salt dominates. The apparent discrepancy of slightly overpredicted concentration and large underpredicted AOD could not be explained by biases in the model RH affecting the particle hygroscopic growth, as modeled RH was found to be comparable to or larger than the in situ measurements. This conundrum could at least partially be explained by the difference in sea salt size distribution; the GEOS simulation has much less sea salt percentage-wise in the smaller particle size range and thus less efficient light extinction than what was observed by PALMS

Convective and Wave Signatures in Ozone Profiles Over the Equatorial Americas: Views from TC4 (2007) and SHADOZ

During the months of July-August 2007 NASA conducted a research campaign called the Tropical Composition, Clouds and Climate Coupling (TC4) experiment. Vertical profiles of ozone were measured daily using an instrument known as an ozonesonde, which is attached to a weather balloon and launch to altitudes in excess of 30 km. These ozone profiles were measured over coastal Las Tablas, Panama (7.8N, 80W) and several times per week at Alajuela, Costa Rica (ION, 84W). Meteorological systems in the form of waves, detected most prominently in 100- 300 in thick ozone layer in the tropical tropopause layer, occurred in 50% (Las Tablas) and 40% (Alajuela) of the soundings. These layers, associated with vertical displacements and classified as gravity waves ("GW," possibly Kelvin waves), occur with similar stricture and frequency over the Paramaribo (5.8N, 55W) and San Cristobal (0.925, 90W) sites of the Southern Hemisphere Additional Ozonesondes (SHADOZ) network. The gravity wave labeled layers in individual soundings correspond to cloud outflow as indicated by the tracers measured from the NASA DC-8 and other aircraft data, confirming convective initiation of equatorial waves. Layers representing quasi-horizontal displacements, referred to as Rossby waves, are robust features in soundings from 23 July to 5 August. The features associated with Rossby waves correspond to extra-tropical influence, possibly stratospheric, and sometimes to pollution transport. Comparison of Las Tablas and Alajuela ozone budgets with 1999-2007 Paramaribo and San Cristobal soundings shows that TC4 is typical of climatology for the equatorial Americas. Overall during TC4, convection and associated meteorological waves appear to dominate ozone transport in the tropical tropopause layer

Multi-Decadal Aerosol Variations from 1980 to 2009: A Perspective from Observations and a Global Model

Aerosol variations and trends over different land and ocean regions during 1980-2009 are analyzed with the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model and observations from multiple satellite sensors and ground-based networks. Excluding time periods with large volcanic influences, the tendency of aerosol optical depth (AOD) and surface concentration over polluted land regions is consistent with the anthropogenic emission changes.The largest reduction occurs over Europe, and regions in North America and Russia also exhibit reductions. On the other hand, East Asia and South Asia show AOD increases, although relatively large amount of natural aerosols in Asia makes the total changes less directly connected to the pollutant emission trends. Over major dust source regions, model analysis indicates that the dust emissions over the Sahara and Sahel respond mainly to the near-surface wind speed, but over Central Asia they are largely influenced by ground wetness. The decreasing dust trend in the tropical North Atlantic is most closely associated with the decrease of Sahel dust emission and increase of precipitation over the tropical North Atlantic, likely driven by the sea surface temperature increase. Despite significant regional trends, the model-calculated global annual average AOD shows little changes over land and ocean in the past three decades, because opposite trends in different regions cancel each other in the global average. This highlights the need for regional-scale aerosol assessment, as the global average value conceals regional changes, and thus is not sufficient for assessing changes in aerosol loading

The Number and Transmission of [PSI+] Prion Seeds (Propagons) in the Yeast Saccharomyces cerevisiae

Yeast (Saccharomyces cerevisiae) prions are efficiently propagated and the on-going generation and transmission of prion seeds (propagons) to daughter cells during cell division ensures a high degree of mitotic stability. The reversible inhibition of the molecular chaperone Hsp104p by guanidine hydrochloride (GdnHCl) results in cell division-dependent elimination of yeast prions due to a block in propagon generation and the subsequent dilution out of propagons by cell division.Analysing the kinetics of the GdnHCl-induced elimination of the yeast [PSI+] prion has allowed us to develop novel statistical models that aid our understanding of prion propagation in yeast cells. Here we describe the application of a new stochastic model that allows us to estimate more accurately the mean number of propagons in a [PSI+] cell. To achieve this accuracy we also experimentally determine key cell reproduction parameters and show that the presence of the [PSI+] prion has no impact on these key processes. Additionally, we experimentally determine the proportion of propagons transmitted to a daughter cell and show this reflects the relative cell volume of mother and daughter cells at cell division.While propagon generation is an ATP-driven process, the partition of propagons to daughter cells occurs by passive transfer via the distribution of cytoplasm. Furthermore, our new estimates of n(0), the number of propagons per cell (500-1000), are some five times higher than our previous estimates and this has important implications for our understanding of the inheritance of the [PSI+] and the spontaneous formation of prion-free cells

Fifth European Dirofilaria and Angiostrongylus Days (FiEDAD) 2016

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