A Reexamination of Phosphorus and Chlorine Depletions in the Diffuse Interstellar Medium

We present a comprehensive examination of interstellar P and Cl abundances based on an analysis of archival spectra acquired with the Space Telescope Imaging Spectrograph of the Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer. Column densities of P II, Cl I, and Cl II are determined for a combined sample of 107 sight lines probing diffuse atomic and molecular gas in the local Galactic interstellar medium (ISM). We reevaluate the nearly linear relationship between the column densities of Cl I and H$_2$, which arises from the rapid conversion of Cl$^+$ to Cl$^0$ in regions where H$_2$ is abundant. Using the observed total gas-phase P and Cl abundances, we derive depletion parameters for these elements, adopting the methodology of Jenkins. We find that both P and Cl are essentially undepleted along sight lines showing the lowest overall depletions. Increasingly severe depletions of P are seen along molecule-rich sight lines. In contrast, gas-phase Cl abundances show no systematic variation with molecular hydrogen fraction. However, enhanced Cl (and P) depletion rates are found for a subset of sight lines showing elevated levels of Cl ionization. An analysis of neutral chlorine fractions yields estimates for the amount of atomic hydrogen associated with the H$_2$-bearing gas in each direction. These results indicate that the molecular fraction in the H$_2$-bearing gas is at least 10% for all sight lines with $\log N({\rm H}_2)\gtrsim18$ and that the gas is essentially fully molecular at $\log N({\rm H}_2)\approx21$.Comment: 44 pages, 21 figures, accepted for publication in Ap

Antibiotic treatment triggers gut dysbiosis and modulates metabolism in a chicken model of gastro-intestinal infection

Background: Infection of the digestive track by gastro-intestinal pathogens results in the development of symptoms ranging from mild diarrhea to more severe clinical signs such as dysentery, severe dehydration and potentially death. Although, antibiotics are efficient to tackle infections, they also trigger dysbiosis that has been suggested to result in variation in weight gain in animal production systems. Results: Here is the first study demonstrating the metabolic impact of infection by a gastro-intestinal pathogen (Brachyspira pilosicoli) and its resolution by antibiotic treatment (tiamulin) on the host (chicken) systemic metabolism and gut microbiota composition using high-resolution 1H nuclear magnetic resonance (NMR) spectroscopy and 16S rDNA next generation sequencing (NGS). Clear systemic metabolic markers of infections such as glycerol and betaine were identified. Weight loss in untreated animals was in part explained by the observation of a modification of systemic host energy metabolism characterized by the utilization of glycerol as a glucose precursor. However, antibiotic treatment triggered an increased VLDL/HDL ratio in plasma that may contribute to reducing weight loss observed in treated birds. All metabolic responses co-occurred with significant shift of the microbiota upon infection or antibiotic treatment. Conclusion: This study indicates that infection and antibiotic treatment trigger dysbiosis that may impact host systemic energy metabolism and cause phenotypic and health modifications

Spitzer observations of HH54 and HH7-11: mapping the H2 ortho-to-para ratio in shocked molecular gas

We report the results of spectroscopic mapping observations carried out toward the Herbig-Haro objects HH7-11 and HH54 over the 5.2 - 37 micron region using the Infrared Spectrograph of the Spitzer Space Telescope. These observations have led to the detection and mapping of the S(0) - S(7) pure rotational lines of molecular hydrogen, together with emissions in fine structure transitions of Ne+, Si+, S, and Fe+. The H2 rotational emissions indicate the presence of warm gas with a mixture of temperatures in the range 400 - 1200 K, consistent with the expected temperature behind nondissociative shocks of velocity ~ 10 - 20 km/s, while the fine structure emissions originate in faster shocks of velocity 35 - 90 km/s that are dissociative and ionizing. Maps of the H2 line ratios reveal little spatial variation in the typical admixture of gas temperatures in the mapped regions, but show that the H2 ortho-to-para ratio is quite variable, typically falling substantially below the equilibrium value of 3 attained at the measured gas temperatures. The non-equilibrium ortho-to-para ratios are characteristic of temperatures as low as ~ 50 K, and are a remnant of an earlier epoch, before the gas temperature was elevated by the passage of a shock. Correlations between the gas temperature and H2 ortho-to-para ratio show that ortho-to-para ratios < 0.8 are attained only at gas temperatures below ~ 900 K; this behavior is consistent with theoretical models in which the conversion of para- to ortho-H2 behind the shock is driven by reactive collisions with atomic hydrogen, a process which possesses a substantial activation energy barrier (E_A/k ~ 4000 K) and is therefore very inefficient at low temperature.Comment: 45 pages, including 16 figures. Accepted for publication in Ap

Consumo de nutrientes de dietas contendo diferentes níveis de farelo de melancia forrageira (Citrullus lanatus cv. Citroides), em ovinos.

Utilizou-se 20 cordeiros, com idade média de seis meses e peso vivo médio de 11,2 kg (+- 1,2), submetidos a um delineamento experimental inteiramente casuaiizado, para determinar os consumos de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), extrato etéreo (EE), fibra em detergente neutro (FDN) e carboidratos totais (CHOT). Cinco dietas contendo D1:80; D2:65; D3:50; D4:35 e D5:20% de farelo de melancia como conncentrado e feno de guandu taipeiro como volumoso, foram avaliadas. As análises estatísticas das variáveis estudadas foram interpretadas por análises de variância e de regressão os consumos de MS, MO, PB, CHOT e FDN, expressos em g/dia, apresentaram um comportamento quadrático (P<0,05) com o aumento do nível de farelo de melancia nas dietas, enquanto o consumo de EE não foi alterado. As diferentes proporções de farelo de melancia e feno de guandu taipeiro, utilizadas nas dietas não proporcionaram um consumo de nutrientes adequado para ovinos

Unusually Weak Diffuse Interstellar Bands toward HD 62542

As part of an extensive survey of diffuse interstellar bands (DIBs), we have obtained optical spectra of the moderately reddened B5V star HD 62542, which is known to have an unusual UV extinction curve of the type usually identified with dark clouds. The typically strongest of the commonly catalogued DIBs covered by the spectra -- those at 5780, 5797, 6270, 6284, and 6614 A -- are essentially absent in this line of sight, in marked contrast with other lines of sight of similar reddening. We compare the HD 62542 line of sight with others exhibiting a range of extinction properties and molecular abundances and interpret the weakness of the DIBs as an extreme case of deficient DIB formation in a dense cloud whose more diffuse outer layers have been stripped away. We comment on the challenges these observations pose for identifying the carriers of the diffuse bands.Comment: 20 pages, 4 figures; aastex; accepted by Ap

Uso do farelo de melancia forrageira (Citrullus lanatus cv. Citroides) e do feno de guandu (Cajanus cajan (L.) Millspaugh cv. D1 Type.), em dietas para ovinos: digestibilidade de nutrientes.

Para se determinarem os coeficientes de digestibilidade da matéria seca (MS), matéria (MO), proteína bruta (PB), extrato etéreo (EE), fibra em detergente neutro (FDN) e carboidratos totais (CHOT), foi realizado um ensaio de digestibilidade, utilizando-se cinco dietas contendo D1:80; D2:65; D3:50; 1)4:35 e D5:20% de farelo de melancia como concentrado e feno de guandu taipeiro como volumoso. Vinte cordeiros mestiços, com idade média de seis meses e peso vivo médio de 11,2 kg (+-1,2), foram submetidos a um delineamento inteiramente casualizado, com cinco tratamentos e quatro repetições. O nível de farelo de melancia forrageira na dieta influenciou linearmente a digestibilidade aparente da MO (62 a 54%) e dos CHOT (58 a 47%). A digestibilidade da PB teve um comportamento cúbico. Os níveis de concentrado não influenciaram a digestibilidade da MS, FDN e do EE. Pode-se concluir que os coeficientes de digestibilidade dos nutrientes das dietas, foram satisfatórios e próximos aos valores encontrados para algumas dietas e forrageiras utilizadas para ovinos, no semi-árido nordestino

Simplifying Multiple Sums in Difference Fields

In this survey article we present difference field algorithms for symbolic summation. Special emphasize is put on new aspects in how the summation problems are rephrased in terms of difference fields, how the problems are solved there, and how the derived results in the given difference field can be reinterpreted as solutions of the input problem. The algorithms are illustrated with the Mathematica package \SigmaP\ by discovering and proving new harmonic number identities extending those from (Paule and Schneider, 2003). In addition, the newly developed package \texttt{EvaluateMultiSums} is introduced that combines the presented tools. In this way, large scale summation problems for the evaluation of Feynman diagrams in QCD (Quantum ChromoDynamics) can be solved completely automatically.Comment: Uses svmult.cls, to appear as contribution in the book "Computer Algebra in Quantum Field Theory: Integration, Summation and Special Functions" (www.Springer.com

Characteristics of Staphylococcus aureus Infections, Chicago Pediatric Hospital

Invasive and skin community-associated (CA)–methicillin-resistant Staphylococcus aureus (MRSA) isolates from children were matched with invasive CA–methicillin-sensitive S. aureus strains during 2000–2004. Isolates were analyzed for presence of Panton-Valentine leukocidin. A USA400 lineage clone (n = 6) and the predominant USA300 lineage clone emerged

Non-smooth developable geometry for interactively animating paper crumpling

International audienceWe present the first method to animate sheets of paper at interactive rates, while automatically generating a plausible set of sharp features when the sheet is crumpled. The key idea is to interleave standard physically-based simulation steps with procedural generation of a piecewise continuous developable surface. The resulting hybrid surface model captures new singular points dynamically appearing during the crumpling process, mimicking the effect of paper fiber fracture. Although the model evolves over time to take these irreversible damages into account, the mesh used for simulation is kept coarse throughout the animation, leading to efficient computations. Meanwhile, the geometric layer ensures that the surface stays almost isometric to its original 2D pattern. We validate our model through measurements and visual comparison with real paper manipulation, and show results on a variety of crumpled paper configurations