Mass-loading of bow shock pulsar wind nebulae

We investigate the dynamics of bow shock nebulae created by pulsars moving supersonically through a partially ionized interstellar medium. A fraction of interstellar neutral hydrogen atoms penetrating into the tail region of a pulsar wind will undergo photo-ionization due to the UV light emitted by the nebula, with the resulting mass loading dramatically changing the flow dynamics of the light leptonic pulsar wind. Using a quasi 1-D hydrodynamic model of relativistic flow we find that if a relatively small density of neutral hydrogen, as low as $10^{-4}$ cm$^{-3}$, penetrate inside the pulsar wind, this is sufficient to strongly affect the tail flow. Mass loading leads to the fast expansion of the pulsar wind tail, making the tail flow intrinsically non-stationary. The shapes predicted for the bow shock nebulae compare well with observations, both in H$\alpha$ and X-rays.Comment: 7 pages, 2 figures. Proceeding to the conference "High Energy Phenomena in Relativistic Outflow V", La Plata 2015, AAA Workshop Series 8, 201

Contribution to diffuse gamma-ray emission coming from self-confined CRs around their Galactic sources

Recent observations of the diffuse Galactic gamma-ray emission by the Fermi-LAT satellite have shown significant deviations from models which assume the same diffusion properties for cosmic rays (CR) throughout the Galaxy. We explore the possibility that a fraction of this diffuse Galactic emission could be due to hadronic interactions of CRs self-confined in the region around their sources. In fact, freshly accelerated CRs that diffuse away from the acceleration region can trigger the streaming instability able to amplify magnetic disturbance and to reduce the particle diffusion. When this happen, CRs are trapped in the near source region for a time longer than expected and an extended gamma-ray halo is produces around each source. Here we calculate the contribution to the diffuse gamma-ray background due to the overlap along lines of sight of several of these extended halos. We find that if the density of neutrals is low, the halos can account for a substantial fraction of the diffuse emission observed by Fermi-LAT, depending on the orientation of the line of sight with respect to the direction of the galactic center.Comment: 8 pages, 2 figs. Proceeding the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Kore

On Particle Acceleration around Shocks. III. Shock Waves Moving at Arbitrary Speed. The Case of Large-Scale Magnetic Field and Anisotropic Scattering

A mathematical approach to investigate particle acceleration at shock waves moving at arbitrary speed in a medium with arbitrary scattering properties was first discussed in work by Vietri and Blasi. We use this method and somewhat extend it in order to include the effect of a large-scale magnetic field in the upstream plasma, with arbitrary orientation with respect to the direction of motion of the shock. We also use this approach to investigate the effects of anisotropic scattering on spectra and anisotropies of the distribution function of the accelerated particles

A 22-Week-Old Fetus with Nager Syndrome and Congenital Diaphragmatic Hernia due to a Novel SF3B4 Mutation.

Nager syndrome, or acrofacial dysostosis type 1 (AFD1), is a rare multiple malformation syndrome characterized by hypoplasia of first and second branchial arches derivatives and appendicular anomalies with variable involvement of the radial/axial ray. In 2012, AFD1 has been associated with dominant mutations in SF3B4. We report a 22-week-old fetus with AFD1 associated with diaphragmatic hernia due to a previously unreported SF3B4 mutation (c.35-2A>G). Defective diaphragmatic development is a rare manifestation in AFD1 as it is described in only 2 previous cases, with molecular confirmation in 1 of them. Our molecular finding adds a novel pathogenic splicing variant to the SF3B4 mutational spectrum and contributes to defining its prenatal/fetal phenotype

Britain avoids talking about COVID-19 deaths. that’s a mistake

How has the UK government acknowledged and talked about COVID-19 deaths? In an extract from their new report, Katharine M Millar, Yuna Han, Katharina Kuhn, Martin Bayly and Irene Morlino (LSE) warn that the current focus on ‘recovery’ and ‘inevitable’ deaths risks alienating sections of society, and suggest how it can do better. Pandemics present a ... Continue

Constraining the cosmic ray spectrum in the vicinity of the supernova remnant W28:from sub-GeV to multi-TeV energies

Supernova remnants interacting with molecular clouds are ideal laboratories to study the acceleration of particles at shock waves and their transport and interactions in the surrounding interstellar medium. In this paper, we focus on the supernova remnant W28, which over the years has been observed in all energy domains from radio waves to very-high-energy gamma rays. The bright gamma-ray emission detected from molecular clouds located in its vicinity revealed the presence of accelerated GeV and TeV particles in the region. An enhanced ionization rate has also been measured by means of millimetre observations, but such observations alone cannot tell us whether the enhancement is due to low energy (MeV) cosmic rays (either protons or electrons) or the X-ray photons emitted by the shocked gas. The goal of this study is to determine the origin of the enhanced ionization rate and to infer from multiwavelength observations the spectrum of cosmic rays accelerated at the supernova remnant shock in the unprecedented range spanning from MeV to multi-TeV particle energies. We developed a model to describe the transport of X-ray photons into the molecular cloud, and we fitted the radio, millimeter, and gamma-ray data to derive the spectrum of the radiating particles. The contribution from X-ray photons to the enhanced ionization rate is negligible, and therefore the ionization must be due to cosmic rays. Even though we cannot exclude a contribution to the ionization rate coming from cosmic ray electrons, we show that a scenario where cosmic ray protons explain both the gamma-ray flux and the enhanced ionization rate provides the most natural fit to multiwavelength data. This strongly suggests that the intensity of CR protons is enhanced in the region for particle energies in a very broad range covering almost 6 orders of magnitude: from $\lesssim 100$ MeV up to several tens of TeV

Grammage of cosmic rays in the proximity of supernova remnants embedded in a partially ionized medium

We investigate the damping of Alfv\'en waves generated by the cosmic ray resonant streaming instability in the context of the cosmic ray escape and propagation in the proximity of supernova remnants. We consider ion-neutral damping, turbulent damping and non linear Landau damping in the warm ionized and warm neutral phases of the interstellar medium. For the ion-neutral damping, up-to-date damping coefficients are used. We investigate in particular whether the self-confinement of cosmic rays nearby sources can appreciably affect the grammage. We show that the ion-neutral damping and the turbulent damping effectively limit the residence time of cosmic rays in the source proximity, so that the grammage accumulated near sources is found to be negligible. Contrary to previous results, this also happens in the most extreme scenario where ion-neutral damping is less effective, namely in a medium with only neutral helium and fully ionized hydrogen. Therefore, the standard picture, in which CR secondaries are produced during the whole time spent by cosmic rays throughout the Galactic disk, need not to be deeply revisited.Comment: 13 pages, 9 figures, submitted to MNRA

Nutritional Screening and Anthropometry in Patients Admitted From the Emergency Department

Background: Due to the high prevalence of malnutrition among hospitalized patients, screening and assessment of nutritional status should be routinely performed upon hospital admission. The main objective of this observational study was to evaluate the prevalence of and the risk for malnutrition, as identified by using three nutritional screening tests, and to observe whether some anthropometric and functional parameters used for nutritional evaluation were related to these test scores. Methods: This single-center observational study included 207 patients admitted from the emergency department for hospitalization in either the internal medicine or surgery units of our institution from September 2017 to December 2018. The prevalence of malnutrition among this patient sample was evaluated by using the Nutritional Risk Screening (NRS-2002), the Subjective Global Assessment (SGA) and the Global Leadership Initiative on Malnutrition (GLIM) criteria. Body mass index (BMI), bioimpedance analysis (BIA), handgrip strength (HGS) and calf circumference (CC) assessments were also performed. Results: According to the NRS-2002, 93% of the patients were at no risk or at low nutritional risk (NRS score < 3), and 7% were at a high nutritional risk (NRS score ≥ 3). On the other hand, according to the SGA, 46.3% of the patients were well-nourished (SGA-a), 49.8% were moderately malnourished (SGA-b), and 3.9% were severely malnourished (SGA-c). Finally, according to the GLIM criteria, 18% patients were malnourished. Body weight, body mass index (BMI), phase angle (PhA), CC and HGS were significantly lower in the patients with NRS scores ≥ 3, SGA-c and in patients with stage 1 and stage 2 malnutrition, according to the GLIM criteria. Conclusion: The NRS-2002, the SGA and the GLIM criteria appear to be valuable tools for the screening and assessment of nutritional status. In particular, the lowest NRS-2002, SGA and GLIM scores were associated with the lowest PhA and CC. Nevertheless, a weekly re-evaluation of patients with better screening and assessment scores is recommended to facilitate early detection of changes in nutritional status

Core-collapse model of broadband emission from SNR RX J1713.7-3946 with thermal X-rays and Gamma-rays from escaping cosmic rays

We present a spherically symmetric, core-collapse model of SNR RX J1713.7-3946 that includes a hydrodynamic simulation of the remnant evolution coupled to the efficient production of cosmic rays (CRs) by nonlinear diffusive shock acceleration (DSA). High-energy CRs that escape from the forward shock (FS) are propagated in surrounding dense material that simulates either a swept-up, pre-supernova shell or a nearby molecular cloud. The continuum emission from trapped and escaping CRs, along with the thermal X-ray emission from the shocked heated ISM behind the FS, integrated over the remnant, is compared against broadband observations. Our results show conclusively that, overall, the GeV-TeV emission is dominated by inverse-Compton from CR electrons if the supernova is isolated regardless of its type, i.e., not interacting with a >>100 Msun shell or cloud. If the SNR is interacting with a much larger mass >10^4 Msun, pion-decay from the escaping CRs may dominate the TeV emission, although a precise fit at high energy will depend on the still uncertain details of how the highest energy CRs are accelerated by, and escape from, the FS. Based on morphological and other constraints, we consider the 10^4 Msun pion-decay scenario highly unlikely for SNR RX J1713.7-3946 regardless of the details of CR escape. Importantly, even though CR electrons dominate the GeV-TeV emission, the efficient production of CR ions is an essential part of our leptonic model.Comment: 11 pages with 7 figures. Submitted to Ap