First Results for the Solar Neighborhood of the Asiago Red Clump Survey

The Asiago Red Clump Spectroscopic Survey (ARCS) is an ongoing survey that provides atmospheric parameters, distances and space velocities of a well selected sample of Red Clump stars distributed along the celestial equator. We used the ARCS catalog for a preliminary investigation of the Galactic disk in the Solar Neighborhood, in particular we focused on detection and characterization of moving groups.Comment: 2 pages, 1 figure, to appear in the proceedings of "Assembling the Puzzle of the Milky Way", Le Grand Bornand (April 17-22, 2011), C. Reyle, A. Robin, M. Schultheis (eds.

A first experimental test of de Broglie-Bohm theory against standard quantum mechanics

De Broglie - Bohm (dBB) theory is a deterministic theory, built for reproducing almost all Quantum Mechanics (QM) predictions, where position plays the role of a hidden variable. It was recently shown that different coincidence patterns are predicted by QM and dBB when a double slit experiment is realised under specific conditions and, therefore, an experiment can test the two theories. In this letter we present the first realisation of such a double slit experiment by using correlated photons produced in type I Parametric Down Conversion. Our results confirm QM contradicting dBB predictions

The European Scleroderma Trials and Research group (EUSTAR) task force for the development of revised activity criteria for systemic sclerosis: derivation and validation of a preliminarily revised EUSTAR activity index

Background Validity of European Scleroderma Study Group (EScSG) activity indexes currently used to assess disease activity in systemic sclerosis (SSc) has been criticised. Methods Three investigators assigned an activity score on a 0–10 scale for 97 clinical charts. The median score served as gold standard. Two other investigators labelled the disease as inactive/moderately active or active/very active. Univariate–multivariate linear regression analyses were used to define variables predicting the ‘gold standard’, their weight and derive an activity index. The cut-off point of the index best separating active/very active from inactive/moderately active disease was identified by a receiver-operating curve analysis. The index was validated on a second set of 60 charts assessed by three different investigators on a 0–10 scale and defined as inactive/moderately active or active/very active by other two investigators. One hundred and twenty-three were investigated for changes over time in the index and their relationships with those in the summed Medsger severity score (MSS). Results A weighted 10-point activity index was identified and validated: Δ-skin=1.5 (Δ=patient assessed worsening during the previous month), modified Rodnan skin score (mRss) \u3e18=1.5, digital ulcers=1.5, tendon friction rubs=2.25, C-reactive protein \u3e1 mg/dL=2.25 and diffusing capacity of the lung for CO (DLCO) % predicted \u3c70%=1.0. A cut-off ≥2.5 was found to identify patients with active disease. Changes in the index paralleled those of MSS (p=0.0001). Conclusions A preliminarily revised SSc activity index has been developed and validated, providing a valuable tool for clinical practice and observational studies

EU Peatlands: Current Carbon Stocks and Trace Gas Fluxes

Peatlands in Europe has formed a significant sink for atmospheric CO2 since the last glacial maximum. Currently they are estimated to hold ca. 42 Gt carbon in the form of peat and are therefore a considerable component in the European carbon budget. Due to the generally wet soil conditions in peatlands they are also significant emitters of the strong greenhouse gas (GHG) methane (CH4) and in some cases also of nitrous oxide (N2O). The EU funded CarboEurope-GHG Concerted Action attempts to develop a reliable and complete greenhouse gas budget for Europe and this report aims to provide a review and synthesis of the available information about GHG exchanges in European peatlands and their underlying processes. A best estimate for all the European countries shows that some are currently sinks for atmospheric CO2 while others are sources. In contrast, for CH4 and N2O, only the sources are relevant. Whilst some countries are CO2 sinks, all countries are net GHG emitters from peatlands. The results presented, however, carry large uncertainties, which cannot be adequately quantified yet. One outstanding uncertainty is the distribution of land use types, particular in Russia, the largest European peat nation. The synthesis of GHG exchange, nevertheless, indicates some interesting features. Russia hosts an estimated 41% of European peatlands and contributes most to all GHG exchanges (CO2: 25%, CH4: 52%, N2O: 26%, Total: 37%). Germany is the second-largest emitter (12% of European total) although it contains only 3.2% of European peatlands. The reason is the use of most of the peatland area for intensive cropland and grassland. The largest CO2 emitters are countries with large agricultural peatland areas (Russia, Germany, Belarus, Poland), the largest N2O emitters are those with large agricultural fen areas (Russia, Germany, Finland). In contrast, the largest CH4 emitters are concentrated in regions with large areas of intact mires, namely Russia and Scandinavia. High average emission densities above 3.5 t C-equiv. ha-1 are found in the Southeast Mediterranean, Germany and the Netherlands where agricultural use of peatlands is intense. Low average emission densities below 0.3 t C-equiv. ha-1 occur where mires and peatland forests dominate, e.g. Finland and the UK. This report concludes by pointing at key gaps in our knowledge about peatland carbon stocks and GHG exchanges which include insufficient basic information on areal distribution of peatlands, measurements of peat depth and also a lack of flux datasets providing full annual budgets of GHG exchanges

The Diguanylate Cyclase SadC Is a Central Player in Gac/Rsm-Mediated Biofilm Formation in Pseudomonas aeruginosa

Pseudomonas aeruginosa is a Gram-negative opportunistic human pathogen and a threat for immune-compromised and Cystic Fibrosis patients. It is responsible for acute and chronic infections and can switch between these lifestyles upon taking an informed decision involving complex regulatory networks. The RetS/LadS/Gac/Rsm network and the c-di-GMP signaling pathways are both central to this phenomenon redirecting the P. aeruginosa population towards a biofilm mode of growth, which is associated with chronic infections. While these two pathways were traditionally studied independently from each other, we recently showed that cellular levels of c-di-GMP are increased in the hyperbiofilm retS mutant. Here, we have formally established the link between the two networks by showing that the SadC diguanylate cyclase is central to the Gac/Rsm-associated phenotypes, notably biofilm formation. Importantly, SadC is involved in the signaling that converges onto the RsmA translational repressor either via RetS/LadS or via HptB/HsbR. Although the level of expression of the sadC gene does not seem impacted by the regulatory cascade, the production of the SadC protein is tightly repressed by RsmA. This adds to the growing complexity of the signaling network associated with c-di-GMP in P. aeruginosa. While this organism possesses more than forty c-di-GMP-related enzymes it remains unclear how signaling specificity is maintained within the c-di-GMP network. The finding that SadC but no other diguanylate cyclase is related to the formation of biofilm governed by the Gac/Rsm pathway further contributes to understand this insulation mechanism

Novel targets of the CbrAB/Crc carbon catabolite control system revealed by transcript abundance in Pseudomonas aeruginosa.

The opportunistic human pathogen Pseudomonas aeruginosa is able to utilize a wide range of carbon and nitrogen compounds, allowing it to grow in vastly different environments. The uptake and catabolism of growth substrates are organized hierarchically by a mechanism termed catabolite repression control (Crc) whereby the Crc protein establishes translational repression of target mRNAs at CA (catabolite activity) motifs present in target mRNAs near ribosome binding sites. Poor carbon sources lead to activation of the CbrAB two-component system, which induces transcription of the small RNA (sRNA) CrcZ. This sRNA relieves Crc-mediated repression of target mRNAs. In this study, we have identified novel targets of the CbrAB/Crc system in P. aeruginosa using transcriptome analysis in combination with a search for CA motifs. We characterized four target genes involved in the uptake and utilization of less preferred carbon sources: estA (secreted esterase), acsA (acetyl-CoA synthetase), bkdR (regulator of branched-chain amino acid catabolism) and aroP2 (aromatic amino acid uptake protein). Evidence for regulation by CbrAB, CrcZ and Crc was obtained in vivo using appropriate reporter fusions, in which mutation of the CA motif resulted in loss of catabolite repression. CbrB and CrcZ were important for growth of P. aeruginosa in cystic fibrosis (CF) sputum medium, suggesting that the CbrAB/Crc system may act as an important regulator during chronic infection of the CF lung

Invasive North American bullfrogs transmit lethal fungus Batrachochytrium dendrobatidis infections to native amphibian host species

Invasive species can be a threat to native species in several ways, including transmitting lethal infections caused by the parasites they carry. However, invasive species may also be plagued by novel and lethal infections they acquire when invading, making inferences regarding the ability of an invasive host to vector disease difficult from field observations of infection and disease. This is the case for the pathogenic fungus Batrachochytrium dendrobatidis (Bd) in Europe and one invasive host species, the North American bullfrog Lithobates catesbeianus, hypothesized to be responsible for vectoring lethal infection to European native amphibians. We tested this hypothesis experimentally using the alpine newt Ichthyosaura alpestris as our model native host. Our results show that infected bullfrog tadpoles are effective vectors of Bd. Native adult newts co-housed with experimentally infected bullfrog tadpoles became Bd infected (molecular and histological tests). Moreover, the exposed adult newts suffered mortality while the majority of infected bullfrog tadpoles survived until metamorphosis. Invasive species can be a threat to native species in several ways, including transmitting lethal infections caused by the parasites they carry. However, invasive species may also be plagued by novel and lethal infections they acquire when invading, making inferences regarding the ability of an invasive host to vector disease difficult from field observations of infection and disease. This is the case for the pathogenic fungus Batrachochytrium dendrobatidis (Bd) in Europe and one invasive host species, the North American bullfrog Lithobates catesbeianus, hypothesized to be responsible for vectoring lethal infection to European native amphibians. We tested this hypothesis experimentally using the alpine newt Ichthyosaura alpestris as our model native host. Our results show that infected bullfrog tadpoles are effective vectors of Bd. Native adult newts co-housed with experimentally infected bullfrog tadpoles became Bd infected (molecular and histological tests). Moreover, the exposed adult newts suffered mortality while the majority of infected bullfrog tadpoles survived until metamorphosis. These results cannot resolve the historical role of alien species in establishing the distribution of Bd across Europe or other regions in the world where this species was introduced, but they show its potential role as a Bd reservoir capable of transmitting lethal infections to native amphibians. Finally, our results also suggest that the removal of infected bullfrogs from aquatic environments may serve to reduce the availability of Bd in European amphibian communities, offering another justification for bullfrog eradication programmes that are currently underway or may be considere

Undamped electrostatic plasma waves

Electrostatic waves in a collision-free unmagnetized plasma of electrons with fixed ions are investigated for electron equilibrium velocity distribution functions that deviate slightly from Maxwellian. Of interest are undamped waves that are the small amplitude limit of nonlinear excitations, such as electron acoustic waves (EAWs). A deviation consisting of a small plateau, a region with zero velocity derivative over a width that is a very small fraction of the electron thermal speed, is shown to give rise to new undamped modes, which here are named {\it corner modes}. The presence of the plateau turns off Landau damping and allows oscillations with phase speeds within the plateau. These undamped waves are obtained in a wide region of the $(k,\omega_{_R})$ plane ($\omega_{_R}$ being the real part of the wave frequency and $k$ the wavenumber), away from the well-known `thumb curve' for Langmuir waves and EAWs based on the Maxwellian. Results of nonlinear Vlasov-Poisson simulations that corroborate the existence of these modes are described. It is also shown that deviations caused by fattening the tail of the distribution shift roots off of the thumb curve toward lower $k$-values and chopping the tail shifts them toward higher $k$-values. In addition, a rule of thumb is obtained for assessing how the existence of a plateau shifts roots off of the thumb curve. Suggestions are made for interpreting experimental observations of electrostatic waves, such as recent ones in nonneutral plasmas.Comment: 11 pages, 10 figure