Thermal instability with the effect of cosmic-ray diffusion

We study dynamical effects of cosmics rays (CRs) on the thermal instability in the linear regime. CRs and the thermal plasma are treated as two different interacting fluids, in which CRs can diffuse along the magnetic field lines. We show that growth rate of the magnetothermal condensation mode is reduced because of the existence of CRs and this stabilizing effect depends on the diffusion coefficient and the ratio of the CRs pressure to gas pressure. Thus, a slower rate of structure formation via thermal instability is predicted when CRs are considered.Comment: accepted by MNRA

Dupilumab efficacy in uncontrolled, moderate-to-severe asthma with self-reported chronic rhinosinusitis

BACKGROUND: Dupilumab, a fully human monoclonal antibody, blocks the shared receptor component for IL-4 and IL-13 signaling, key drivers of type 2 inflammation. In the phase 3 study (NCT02414854), add-on dupilumab 200 mg/300 mg every 2 weeks, versus placebo, significantly reduced severe asthma exacerbations and improved pre-bronchodilator forced expiratory volume in 1 second (FEV OBJECTIVE: To assess the efficacy and safety of dupilumab in patients with uncontrolled, moderate-to-severe asthma with or without self-reported comorbid chronic rhinosinusitis (CRS or non-CRS). METHODS: Comorbid CRS was self-reported by patients using an e-diary. Annualized severe exacerbation rates, changes from baseline in pre- and post-bronchodilator FEV RESULTS: CRS was self-reported by 382 of 1902 (20.1%) patients. Dupilumab 200 mg/300 mg reduced annualized severe exacerbation rates by 63%/61%, respectively, in patients with CRS, and by 42%/40% in patients without CRS (all P \u3c .001 vs placebo). Dupilumab also improved lung function and patient-reported asthma control and quality of life, and suppressed type 2 biomarkers versus placebo in both subgroups. Clinical responses were rapid, with near-maximal responses observed at the earliest measured time points and sustained at week 52. Improvements observed in the CRS subgroup were similar to or numerically greater than those in the non-CRS subgroup. CONCLUSION: Dupilumab showed efficacy and was generally well tolerated in patients with uncontrolled, moderate-to-severe asthma with or without CRS

A case-control study of medical, psychological and socio-economic factors influencing the severity of chronic rhinosinusitis

BACKGROUND: Chronic rhinosinusitis (CRS) is a common and debilitating disorder. Little is known about the epidemiology of this disease. The aims of the study were to identify differences in socio-economic variables and quality of life between patients with chronic rhinosinusitis and healthy controls, to identify any significant associations between CRS and other medical co-morbidities, psychiatric disease or environmental exposure and to explore the experience of CRS from the perspective of CRS sufferers. METHODS: Participants were recruited from ENT clinics from 30 centres across the UK. They completed a study-specific questionnaire considering environmental, medical and socio-economic factors, and SF-36 and SNOT-22 scores. All participants with CRS were diagnosed by a clinician and categorised as having CRS (with polyposis, without polyposis or allergic fungal rhinosinusitis (AFRS)). Controls included family and friends of those attending ENT outpatient clinics and hospital staff who had no diagnosis of nose or sinus problems and had not been admitted to hospital in the previous 12 months. RESULTS: A total of 1470 study participants (1249 patients and 221 controls) were included in the final analysis. Highly significant differences were seen in generic and disease-specific quality of life scores between CRS sufferers and controls; mean SNOT-22 score 45.0 for CRS compared with 12.1 amongst controls. There were no clear differences in socioeconomic variables including social class, index of multiple deprivation and educational attainment between cases and controls. Common comorbidities with a clear association included respiratory and psychiatric disorders, with a higher frequency of reported upper respiratory tract infections. CONCLUSIONS: CRS is associated with significant impairment in quality of life and with certain medical co-morbidities. In contrast to other common ENT disorders, no socioeconomic differences were found between patients and controls in this study

Interpretation of the excess of antiparticles within a modified paradigm of galactic cosmic rays

We argue that the anomalously high fluxes of positrons and antiprotons found in cosmic rays (CR) can be satisfactorily explained by introducing two additional elements to the current "standard" paradigm of Galactic CRs. First, we propose that the antiparticles are effectively produced in interactions of primary CRs with the surrounding gas not only in the interstellar medium (ISM) but also inside the accelerators. Secondly, we postulate the existence of two source populations injecting CRs into the ISM with different, (1) soft (close to $FI \propto E^{-2.3}$) and (2) hard ($FII \propto E^{-1.8}$ or harder), energy distributions. Assuming that CRs in the 2nd population of accelerators accumulate "grammage" of the order of $1 \ \rm g/cm^2$ before their leakage into ISM, we can explain the energy distributions and absolute fluxes of both positrons and antiprotons, as well as the fluxes of secondary nuclei of the (Li,Be,B) group. The superposition of contributions of two source populations also explains the reported hardening of the spectra of CR protons and nuclei above 200 GV. The 2nd source population accelerating CRs with a rate at the level below 10 percent of the power of the 1st source population, can be responsible for the highest energy protons and nuclei of Galactic CRs up to the "knee" around $10^{15} \ \rm eV$.Comment: accepted for publication in PR

Superdiffusion of Cosmic Rays: Implications for Cosmic Ray Acceleration

Diffusion of cosmic rays (CRs) is the key process of understanding their propagation and acceleration. We employ the description of spatial separation of magnetic field lines in MHD turbulence in Lazarian & Vishniac (1999) to quantify the divergence of magnetic field on scales less than the injection scale of turbulence and show this divergence induces superdiffusion of CR in the direction perpendicular to the mean magnetic field. The perpendicular displacement squared increases, not as distance $x$ along magnetic field, which is the case for a regular diffusion, but as the $x^{3}$ for freely streaming CRs. The dependence changes to $x^{3/2}$ for the CRs propagating diffusively along magnetic field. In the latter case we show that it is important to distinguish the perpendicular displacement in respect to the mean field and to the local magnetic field. We consider how superdiffusion changes the acceleration of CRs in shocks and show how it decreases efficiency of the CRs acceleration in perpendicular shocks. We also demonstrate that in the case when small-scale magnetic field is being generated in the pre-shock region, an efficient acceleration can take place for the CRs streaming without collisions along magnetic loops.Comment: 18 pages, 6 figures, erratum in eqs.(12,13) and table 1 included, ApJ accepte

Non-thermal Emissions from Cool Cores Heated by Cosmic-Rays in Galaxy Clusters

We study non-thermal emissions from cool cores in galaxy clusters. We adopted a recent model, in which cosmic-rays (CRs) prevail in the cores and stably heat them through CR streaming. The non-thermal emissions come from the interaction between CR protons and intracluster medium (ICM). Comparison between the theoretical predictions and radio observations shows that the overall CR spectra must be steep, and most of the CRs in the cores are low-energy CRs. Assuming that the CRs are injected through AGN activities, we study the nature of the shocks that are responsible for the CR acceleration. The steep CR spectra are likely to reflect the fact that the shocks travel in hot ICM with fairly small Much numbers. We also study the dependence on the CR streaming velocity. The results indicate that synchrotron emissions from secondary electrons should be observed as radio mini-halos in the cores. In particular, low-frequency observations (e.g. LOFAR) are promising. On the other hand, the steepness of the spectra makes it difficult to detect non-thermal X-ray and gamma-ray emissions from the cores. The low-energy CRs may be heating optical filaments observed in the cores.Comment: Accepted for publication in Ap

Interference and Deployment Issues for Cognitive Radio Systems in Shadowing Environments

In this paper we describe a model for calculating the aggregate interference encountered by primary receivers in the presence of randomly placed cognitive radios (CRs). We show that incorporating the impact of distance attenuation and lognormal fading on each constituent interferer in the aggregate, leads to a composite interference that cannot be satisfactorily modeled by a lognormal. Using the interference statistics we determine a number of key parameters needed for the deployment of CRs. Examples of these are the exclusion zone radius, needed to protect the primary receiver under different types of fading environments and acceptable interference levels, and the numbers of CRs that can be deployed. We further show that if the CRs have apriori knowledge of the radio environment map (REM), then a much larger number of CRs can be deployed especially in a high density environment. Given REM information, we also look at the CR numbers achieved by two different types of techniques to process the scheduling information.Comment: to be presented at IEEE ICC 2009. This posting is the same as the original one. Only author's list is updated that was unfortunately not correctly mentioned in first versio