Anisotropy of Electrical Transport and Superconductivity in Metal Chains of Nb2Se3

In this work we have shown bulk superconductivity and studied the anisotropy in both the normal and superconducting states in quasi-1D conductor Nb2Se3. Electron - electron Umklapp scattering dominates electronic transport along the direction of Nb metal chains as well as perpendicular to it. The superconducting state is rather anisotropic with possible multi - band features.Comment: 5 pages, 5 figure

The small GTPase Rab29 is a common regulator of immune synapse assembly and ciliogenesis

Acknowledgements We wish to thank Jorge Galán, Gregory Pazour, Derek Toomre, Giuliano Callaini, Joel Rosenbaum, Alessandra Boletta and Francesco Blasi for generously providing reagents and for productive discussions, and Sonia Grassini for technical assistance. The work was carried out with the financial support of Telethon (GGP11021) and AIRC.Peer reviewedPostprin

From insect to man: Photorhabdus sheds light on the emergence of human pathogenicity

Photorhabdus are highly effective insect pathogenic bacteria that exist in a mutualistic relationship with Heterorhabditid nematodes. Unlike other members of the genus, Photorhabdus asymbiotica can also infect humans. Most Photorhabdus cannot replicate above 34°C, limiting their host-range to poikilothermic invertebrates. In contrast, P. asymbiotica must necessarily be able to replicate at 37°C or above. Many well-studied mammalian pathogens use the elevated temperature of their host as a signal to regulate the necessary changes in gene expression required for infection. Here we use RNA-seq, proteomics and phenotype microarrays to examine temperature dependent differences in transcription, translation and phenotype of P. asymbiotica at 28°C versus 37°C, relevant to the insect or human hosts respectively. Our findings reveal relatively few temperature dependant differences in gene expression. There is however a striking difference in metabolism at 37°C, with a significant reduction in the range of carbon and nitrogen sources that otherwise support respiration at 28°C. We propose that the key adaptation that enables P. asymbiotica to infect humans is to aggressively acquire amino acids, peptides and other nutrients from the human host, employing a so called “nutritional virulence” strategy. This would simultaneously cripple the host immune response while providing nutrients sufficient for reproduction. This might explain the severity of ulcerated lesions observed in clinical cases of Photorhabdosis. Furthermore, while P. asymbiotica can invade mammalian cells they must also resist immediate killing by humoral immunity components in serum. We observed an increase in the production of the insect Phenol-oxidase inhibitor Rhabduscin normally deployed to inhibit the melanisation immune cascade. Crucially we demonstrated this molecule also facilitates protection against killing by the alternative human complement pathway

Leishmania infantum Asparagine Synthetase A Is Dispensable for Parasites Survival and Infectivity

A growing interest in asparagine (Asn) metabolism has currently been observed in cancer and infection fields. Asparagine synthetase (AS) is responsible for the conversion of aspartate into Asn in an ATP-dependent manner, using ammonia or glutamine as a nitrogen source. There are two structurally distinct AS: the strictly ammonia dependent, type A, and the type B, which preferably uses glutamine. Absent in humans and present in trypanosomatids, AS-A was worthy of exploring as a potential drug target candidate. Appealingly, it was reported that AS-A was essential in Leishmania donovani, making it a promising drug target. In the work herein we demonstrate that Leishmania infantum AS-A, similarly to Trypanosoma spp. and L. donovani, is able to use both ammonia and glutamine as nitrogen donors. Moreover, we have successfully generated LiASA null mutants by targeted gene replacement in L. infantum, and these parasites do not display any significant growth or infectivity defect. Indeed, a severe impairment of in vitro growth was only observed when null mutants were cultured in asparagine limiting conditions. Altogether our results demonstrate that despite being important under asparagine limitation, LiAS-A is not essential for parasite survival, growth or infectivity in normal in vitro and in vivo conditions. Therefore we exclude AS-A as a suitable drug target against L. infantum parasites

Decadal variations in wave heights off Cape Kelba, Saaremaa Island, and their relationships with changes in wind climate

Based on wind data from the Vilsandi meteorological station and a 5-month calibration measurement with a bottom-mounted Recording Doppler Current Profiler (RDCP), a semi-empirical hindcast of wave parameters near the quickly developing accumulative Kelba Spit is presented for the period 1966–2006. The significant wave heights with a gross mean value of 0.56 m exhibited some quasiperiodic cycles, with the last high stage in 1980–95 and a decreasing overall trend of −0.001 m per year. At the same time, both the frequency and intensity of high wave events showed rising trends, and the mean wave heights during winter (December to February) increased as well. As the study area has the longest fetches in westerly directions, the discussed tendencies in wave conditions are sensitive to regional changes in the wind climate and can be related to a decrease in the local average wind speed on the one hand, but an intensification of westerly winds, storm events and the wintertime NAO index on the other. The roughest wave storms on record were associated with prominent W-storms on 2 November 1969 and 9 January 2005; a few other extreme wind events (e.g. in 1967, 1999, 2001), however, did not yield equally prominent waves

Currents and waves in the Northern Gulf of Riga: measurement and long-term hindcast

Based on measurements of waves and currents obtained for a period of 302 days with a bottom-mounted RDCP (Recording Doppler Current Profiler) at two differently exposed locations, a model for significant wave height was calibrated separately for those locations; in addition, the Gulf of Riga-Vainameri 2D model was validated, and the hydrodynamic conditions were studied. Using wind forcing data from the Kihnu meteorological station, a set of current, water exchange and wave hindcasts were obtained for the period 1966–2011. Current patterns in the Gulf and in the straits were wind-dependent with characteristic wind switch directions. The Matsi coast was prone to upwelling in persistent northerly wind conditions. During the hindcast period, currents increased along the Koiguste coast and in the Suur Strait, waves decreased noticeably off Koiguste but fluctuated without a clear linear trend near Matsi. The spatially contrasting results for differently exposed coasts were related to the corresponding variations in local wind conditions and to changes in atmospheric circulation patterns over northern Europe

Past and future changes in sea level near the Estonian coast in relation to changes in wind climate

The dependence of sea level on past and future climatological conditions is investigated in nearly tideless semi-enclosed sub-basins of the Baltic Sea using trend analysis of the tide gauge data for the period of 1924–2003 and hydrodynamic modelling. The results suggest that in addition to the effect of eustatic rise in mean sea level and its partial compensation by isostatic land uplift, the water level has risen by up to 6 cm near the Estonian coast during the last fifty years, probably due to changes in wind climate. The sea-level increase was concentrated in the period from November to March. It is in good correlation with increasing trends in local storminess and in higher intensity of westerlies, as described by AO and NAO indices. For the future sea level, a set of sensitivity and scenario runs considering possible future changes in wind climate was performed using a 2D hydrodynamic model with a 1-km grid-step. The scenario runs show that if the intensity of westerlies continues to grow (with less than 20% annual mean wind speed increase) the local annual mean sea level rise up to 5–6 cm can occur in some windward bays of the Gulf of Riga. The rise can be up to 9–11 cm in winter months, while in summer the sea level rise is unlikely. Also, increase in variability and extremes can be expected

Estimation of sea level rise and storm surge risks along the coast of Estonia, Baltic Sea – a tool for coastal management

The aim of the paper is to present statistical analysis of the sea level data obtained from the Estonian coastal tide gauges over the period 1842–2009, to assess storm surge risks and to discuss climate change related mitigation and management issues in the coastal zone of Estonia. Long-term variations of both mean and extreme sea level values were studied in the Eastern section of the nearly tideless Baltic Sea. Influenced by postglacial land uplift, the series of relative sea level displayed slightly varying trends. The remarkably steep rise in annual maximum sea levels (2–12 mm/yr) could be explained by the local response to the changing regional wind climate. Due to its windward location, the sea level variations in the semi-enclosed study area are sensitive to the changes in cyclonic activity. Maximum value analysis revealed that in case of the south-westerly exposed Pärnu Bay, two storm surge events (253 in 1967 and 275 cm in 2005) were inconsistent with the theoretical distributions, which indicate that, in some locations, the most extreme sea level events are hardly predictable by means of return statistics. The parameters of maximum expected storm surges were estimated on the basis of hydrodynamic modelling