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Recently, a diffuse emission of 1–100 GeV γ-rays has been detected from the direction of M31, extending up to 200 kpc from its center. The interpretation of the extended γ-ray emission by the escape of cosmic rays produced in the galactic disk or in the galactic center is problematic. In this paper, we argue that a cosmic-ray origin (either leptonic or hadronic) of the γ-ray emission is possible in the framework of nonstandard cosmic-ray propagation scenarios or is caused by in situ particle acceleration in the galaxy's halo. Correspondingly, the halo is powered by the galaxy's nuclear activity or by the accretion of intergalactic gas. If the formation of cosmic-ray halos around galaxies is a common phenomenon, the interactions of cosmic-ray protons and nuclei with the circumgalactic gas surrounding the Milky Way could be responsible for the isotropic diffuse flux of neutrinos observed by IceCube. [ABSTRACT FROM AUTHOR]

Low-energy cosmic rays are the major ionization agents of molecular clouds. However, it has been shown that, if the cosmic ray spectrum measured by Voyager 1 is representative of the whole Galaxy, the predicted ionization rate in diffuse clouds fails to reproduce data by 1–2 orders of magnitude, implying that an additional source of ionization must exist. One of the solutions proposed to explain this discrepancy is based on the existence of an unknown low-energy (in the range 1 keV–1 MeV, not probed by Voyager) cosmic ray component, called carrot when first hypothesized by Reeves and collaborators in the seventies. Here we investigate the energetic required by such scenario. We show that the power needed to maintain such low-energy component is comparable of even larger than that needed to explain the entire observed cosmic ray spectrum. Moreover, if the interstellar turbulent magnetic field has to sustain a carrot, through second-order Fermi acceleration, the required turbulence level would be definitely too large compared to the one expected at the scale resonant with such low-energy particles. Our study basically rules out all the plausible sources of a cosmic ray carrot, thus making such hidden component unlikely to be an appealing and viable source of ionization in molecular clouds. [ABSTRACT FROM AUTHOR]

We study the problem of the escape and transport of cosmic rays (CRs) from a source embedded in a fully ionized, hot phase of the interstellar medium (HIM). In particular, we model the CR escape and their propagation in the source vicinity taking into account excitation of Alfv´enic turbulence by CR streaming and mechanisms damping the self-excited turbulence itself. Our estimates of escape radii and times result in large values (100 pc, 2 × 105 yr) for particle energies ≲ 20 GeV and smaller values for particles with increasing energies (35 pc and 14 kyr at 1 TeV). These escape times and radii, when used as initial conditions for the CR propagation outside the source, result in relevant suppression of the diffusion coefficient (by a factor 5–10) on time-scales comparable with their (energy dependent) escape time-scale. The damping mechanisms are fast enough that even on shorter time-scales, the Alfv´enic turbulence is efficiently damped, and the ratio between random and ordered component of the magnetic field is δ B / B 0 ≪ 1, justifying the use of quasi-linear theory. In spite of the suppressed diffusion coefficient, and then the increased residence time in the vicinity (≤200 pc) of their source, the grammage accumulated by CRs after their escape is found to be negligible (at all energies) as compared to the one accumulated while diffusing in the whole Galaxy, due to the low density of the HIM. [ABSTRACT FROM AUTHOR]

Purpose: Evaluate effects of maternal immunization in a mouse model of Group B Streptococcus (GBS) vaginal colonization using clinical isolates.Materials and Methods: Female pregnant mice were immunized with heat-killed GBS 21 days before pregnancy and were inoculated intravaginally with GBS cultures (5 × 107 CFU twice a day for three days) from the 16th day of pregnancy. Gestation period and mice survival were monitored. Maternal anti-GBS IgG levels have been determined by ELISA analysis in vaccinated, unvaccinated mothers and newborns.Results: Maternal immunization before pregnancy provided protection to newborns for three of the four GBS strains used. Evaluation of the immunogenicity showed that this vaccination induced higher levels of IgG in vaccinated compared to unvaccinated dams and the presence of antibodies in the offspring at embryonic and postnatal age, and a Th1 response and high levels of IgG2a subclass antibody and IFN-γ were detected. A significant reduction of preterm births was observed in vaccinated mothers (p< 0.05).Conclusions: Our finding suggest that vaccinated mothers could protect their progeny from GBS infection and preterm birth through passive immunization. The proposed mouse model may represent a noninvasive and effective tool to investigate pathogenetic mechanisms of GBS ascending infection and for vaccine protection studies. [ABSTRACT FROM AUTHOR]

Estimates of dissolved CO2 in subduction-zone fluids are based on thermodynamic models, relying on a very sparse experimental data base. Here, we present experimental data at 1-3 GPa, 800 °C, and ΔFMQ ≈ -0.5 for the volatiles and solute contents of graphite-saturated fluids in the systems COH, SiO2-COH ( + quartz/coesite) and MgO-SiO2-COH ( + forsterite and enstatite). The CO2 content of fluids interacting with silicates exceeds the amounts measured in the pure COH system by up to 30 mol%, as a consequence of a decrease in water activity probably associated with the formation of organic complexes containing Si-O-C and Si-O-Mg bonds. The interaction of deep aqueous fluids with silicates is a novel mechanism for controlling the composition of subduction COH fluids, promoting the deep CO2 transfer from the slab-mantle interface to the overlying mantle wedge, in particular where fluids are stable over melts. [ABSTRACT FROM AUTHOR]

Cosmic rays escaping the Galaxy exert a force on the interstellar medium directed away from the Galactic disc. If this force is larger than the gravitational pull due to the mass embedded in the Galaxy, then galactic winds may be launched. Such outflows may have important implications for the history of star formation of the host galaxy, and in turn affect in a crucial way the transport of cosmic rays, both due to advection with the wind and to the excitation of waves by the same cosmic rays, through streaming instability. The possibility to launch cosmic ray-induced winds and the properties of such winds depend on environmental conditions, such as the density and temperature of the plasma at the base of the wind and the gravitational potential, especially the one contributed by the dark matter halo. In this paper, we make a critical assessment of the possibility to launch cosmic ray-induced winds for a Milky Way-like galaxy and how the properties of the wind depend upon the conditions at the base of the wind. Special attention is devoted to the implications of different conditions for wind launching on the spectrum of cosmic rays observed at different locations in the disc of the galaxy. We also comment on how cosmic ray-induced winds compare with recent observations of Oxygen absorption lines in quasar spectra and emission lines from blank sky, as measured by XMM–Newton/EPIC-MOS. [ABSTRACT FROM AUTHOR]

The quantitative assessment of COH fluids is crucial in modeling geological processes. The composition of fluids, and in particular their H2O/ CO2 ratio, can influence the melting temperatures, the location of hydration or carbonation reactions, and the solute transport capability in several rock systems. In the scientific literature, COH fluids speciation has been generally assumed on the basis of thermodynamic calculations using equations of state of simple H2O-nonpolar gas systems (e.g., H2O- CO2- CH4). Only few authors dealt with the experimental determination of high-pressure COH fluid species at different conditions, using diverse experimental and analytical approaches (e.g., piston cylinder + capsule piercing + gas chromatography/mass spectrometry; cold seal + silica glass capsules + Raman). In this contribution, we present a new methodology for the synthesis and the analysis of COH fluids in experimental capsules, which allows the quantitative determination of volatiles in the fluid by means of a capsule-piercing device connected to a quadrupole mass spectrometer. COH fluids are synthesized starting from oxalic acid dihydrate at P = amb and T = 250°C in single capsules heated in a furnace, and at P = 1 GPa and T = 800°C using a piston-cylinder apparatus and the double-capsule technique to control the redox conditions employing the rhenium-rhenium oxide oxygen buffer. A quantitative analysis of H2O, CO2, CH4, CO, H2, O2, and N2 along with associated statistical errors is obtained by linear regression of the m/ z data of the sample and of standard gas mixtures of known composition. The estimated uncertainties are typically <1% for H2O and CO2, and <5% for CO. Our results suggest that the COH fluid speciation is preserved during and after quench, as the experimental data closely mimic the thermodynamic model both in terms of bulk composition and fluid speciation. [ABSTRACT FROM AUTHOR]

The escape of cosmic rays from the Galaxy leads to a gradient in the cosmic ray pressure that acts as a force on the background plasma, in the direction opposite to the gravitational pull. If this force is large enough to win against gravity, a wind can be launched that removes gas from the Galaxy, thereby regulating several physical processes, including star formation. The dynamics of these cosmic ray driven winds is intrinsically non-linear in that the spectrum of cosmic rays determines the characteristics of the wind (velocity, pressure, magnetic field) and in turn the wind dynamics affects the cosmic ray spectrum. Moreover, the gradient of the cosmic ray distribution function causes excitation of Alfvén waves, that in turn determines the scattering properties of cosmic rays, namely their diffusive transport. These effects all feed into each other so that what we see at the Earth is the result of these non-linear effects. Here, we investigate the launch and evolution of such winds, and we determine the implications for the spectrum of cosmic rays by solving together the hydrodynamical equations for the wind and the transport equation for cosmic rays under the action of self-generated diffusion and advection with the wind and the self-excited Alfvén waves. [ABSTRACT FROM AUTHOR]

In this qualitative study, multidimensional characteristics of the emerging leadership behavior of six young children were examined within their early childhood classrooms (infant, toddler, and preschool). Grounded in a constructivist framework, the data were gathered through teacher interviews and classroom observations in a university-affiliated center over a six-week period. Findings yielded two major themes that best described the characteristics of these young leaders: dynamic and charismatic personalities; and a sense of ownership of, and a high awareness in, the classroom. By examining the ways leadership manifested itself in the classroom, findings also suggested that leadership could be seen as a relational rather than an individual construct. Young leaders seem to exert their social power to develop relationships with peers and teachers and at the same time to include and exclude certain peers or teachers during the interaction. Findings are discussed with reference to implications for practice and suggestions for further study.

The NOx storage process over Ba/Al2O3 and Pt–Ba/Al2O3 NSR catalysts has been analyzed in this study by performing experiments at 350 °C with NO2 and NO/O2 mixtures using different complementary techniques (Transient Response Method, in situ FT–IR and DRIFT spectroscopies). The collected data suggest that over the Pt–Ba/Al2O3 catalyst the NOx storage process from NO/O2 mixtures occurs forming at first nitrite species, which progressively evolve to nitrates. In addition, a parallel nitrate formation via disproportionation of NO2 (formed upon NO oxidation) cannot be excluded. [ABSTRACT FROM AUTHOR]

Mouse passage of a stock strain of each of the serotypes Ia, Ib, Ia/c, II and III of Streptococcus agalactiae was followed by increased virulence. The change was associated with an increased content of sialic acid and also with the appearance of an antigen common to all passaged strains. This antigen was subsequently detected in all but one of 12 strains isolated from infected babies or diabetic adults, but in none of 12 organisms recovered from carriers. [ABSTRACT FROM AUTHOR]

Abstract: The presence of fibronectin binding protein genes sfb, fba and prtF1 was evaluated by PCR in a collection of Streptococcus pyogenes strains from invasive diseases and from throat swabs. Sfb and fba genes were found in comparable percentage among the two groups, while prtF1 gene was significantly more frequent among isolates from throat. Each emm type appeared to have a peculiar set of fibronectin binding protein genes, also characterized by the same number of tandem repeats. None of the tested genes appeared to be related to the ability of GAS to invade epithelial cells, independently of the source of isolation. [Copyright &y& Elsevier]

We report our experience with 49 patients who underwent fistulosphincterotomy (FS) after cannulation of the common bile duct (CBD) by standard approaches had failed, due to suspected CBD obstruction. Only 4% of our cases turned out to have no biliary obstruction at all. The morbidity rate was 16%, and the mortality rate was 2%. In our series, FS raised the success rate of CBD cannulation from 90% to 96%. Ninety-five percent of successful cannulations were followed by endoscopic treatment. There were no cases of perforation or hemorrhage, and no difference in the success rate between FS in flat papillas and FS in bulging papillas, thanks, perhaps, to the technique we used. Our findings would indicate that FS is a useful procedure involving additional but not prohibitive risks. Nonetheless, it should be used only when CBD obstruction is strongly suspected and standard methods are not successful. [ABSTRACT FROM AUTHOR]