Nature of Sonoluminescence: Noble Gas Radiation Excited by Hot Electrons in "Cold" Water

We show that strong electric fields occurring in water near the surface of collapsing gas bubbles because of the flexoelectric effect can provoke dynamic electric breakdown in a micron-size region near the bubble and consider the scenario of the SBSL. The scenario is: (i) at the last stage of incomplete collapse of the bubble the gradient of pressure in water near the bubble surface has such a value and sign that the electric field arising from the flexoelectric effect exceeds the threshold field of the dynamic electrical breakdown of water and is directed to the bubble center; (ii) mobile electrons are generated because of thermal ionization of water molecules near the bubble surface; (iii) these electrons are accelerated in ''cold'' water by the strong electric fields; (iv) these hot electrons transfer noble gas atoms dissolved in water to high-energy excited states and optical transitions between these states produce SBSL UV flashes in the trasparency window of water; (v) the breakdown can be repeated several times and the power and duration of the UV flash are determined by the multiplicity of the breakdowns. The SBSL spectrum is found to resemble a black-body spectrum where temperature is given by the effective temperature of the hot electrons. The pulse energy and some other characteristics of the SBSL are found to be in agreement with the experimental data when realistic estimations are made.Comment: 11 pages (RevTex), 1 figure (.ps

GRB 011121: A massive star progenitor

Of the cosmological gamma-ray bursts, GRB 011121 has the lowest redshift, z = 0.36. More importantly, the multicolor excess in the afterglow detected in the Hubble Space Telescope (HST) light curves is compelling observational evidence of an underlying supernova. Here we present near-infrared and radio observations of the afterglow, and from our comprehensive afterglow modeling, we find evidence favoring a wind-fed circumburst medium. Lacking X-ray data, we are unable to conclusively measure the mass-loss rate, M, but obtain an estimate, M ∼ 2 × 10-7/νw3 M⊙yr-1, where νw3 is the speed of the wind from the progenitor in units of 103 km s-1. This M is similar to that inferred for the progenitor of the Type Ibc supernova SN 1998bw that has been associated with the peculiar burst GRB 980425. Our data, taken in conjunction with the HST results of Bloom et al., provide a consistent picture: the long-duration GRB 011121 had a massive star progenitor that exploded as a supernova at about the same time as the gamma-ray burst event. Finally, we note that the gamma-ray profile of GRB 011121 is similar to that of GRB 980425

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

GeoepidemiolÃgicos aspects in juvenile idiopathic arthritis in an equatorial region

nÃo hÃA Artrite IdiopÃtica Juvenil (AIJ) representa a doenÃa articular crÃnica mais comum da infÃncia, sendo constituÃda por subtipos heterogÃneos, com apresentaÃÃes clÃnicas especÃficas. SÃo descritos fatores ambientais que poderiam influenciar na diversidade de expressÃo bem como na gravidade das manifestaÃÃes clÃnicas. O objetivo desta pesquisa foi avaliar a influÃncia de fatores ambientais no quadro clÃnico dos pacientes com AIJ. Selecionou-se aleatoriamente 50 pacientes com AIJ atendidos em hospitais de referÃncia. Esses passaram por avaliaÃÃo clÃnica com especialista, inquÃrito epidemiolÃgico e avaliaÃÃo laboratorial. Determinou-se a exposiÃÃo gestacional ou precoce ao tabagismo materno e familiar, o tempo de amamentaÃÃo, a escolaridade em anos dos pais e a faixa salarial familiar, os nÃveis sÃricos de vitamina D (VitD), sendo esses correlacionados com o grau de atividade clÃnica inflamatÃria atravÃs do escore JADAS (Juvenile Arthritis Disease Activity Score), com o nÃvel de incapacidade fÃsica mensurada pelo CHAQ (Childhood Health Assessment Questionnaire) e a presenÃa de deformidades. Predominou o sexo feminino, com idade mÃdia na avaliaÃÃo de 13,42 anos. O subtipo poliarticular fator reumatÃide negativo foi o mais prevalente (32%) e deformidades articulares foram detectadas em apenas 15 pacientes. Houve predomÃnio da faixa salarial entre 1-3 salÃrios, duraÃÃo da amamentaÃÃo menor que trÃs meses, escolaridade dos pais menor que oito anos e exposiÃÃo ao tabagismo materno e familiar em 10 e 18 pacientes respectivamente; o valor mÃdio do CHAQ foi de 0,36 e 28 pacientes nÃo apresentavam incapacidades; a mÃdia do JADAS foi de 9,1Â11; a mÃdia da VitD foi de 31,52 ng/ml, com 50% apresentando nÃveis suficientes. NÃo se observou relaÃÃo entre o grau de atividade clÃnica (JADAS) e os nÃveis da VitD; NÃo se detectou influÃncia significativa dos demais fatores ambientais no quadro clÃnico. Conclui-se que os nÃveis de vitamina D foram suficientes em metade dos pacientes, provavelmente refletindo a maior exposiÃÃo solar secundÃria à localizaÃÃo geogrÃfica do Estado do Cearà prÃxima a linha do Equador; nÃo se observou correlaÃÃo entre VitD e atividade inflamatÃria na AIJ. Os fatores ambientais nÃo influÃram na apresentaÃÃo clÃnica da AIJ nessa pesquisaThe Juvenile Idiopathic Arthritis (JIA) is the most common chronic disease of childhood, being composed of heterogeneous subtypes with specific clinical presentations. Is described that environmental factors may influence the diversity of expression and the severity of clinical manifestations. The objective of this research was to evaluate the influence of environmental factors on the clinical picture of patients with JIA. Fifty patients with JIA treated at referral hospitals were randomly selected. They underwent clinical evaluation with expert as well as epidemiological investigation and laboratory evaluation. The gestational or early exposure to maternal and family smoking, duration of breastfeeding, parental education in years, family salary range, serum levels of vitamin D (VitD), and these correlated with the degree of clinical inflammatory activity through the JADAS score (Juvenile Arthritis Disease Activity Score), with the level of disability measured by CHAQ (Childhood Health Assessment Questionnaire) and the presence of deformities. Prevailing females and the mean age at assessment was 13,42 years. The rheumatoid factor negative polyarthritis subtype was the most prevalent (32%) and only 15 patients have deformities. There was a predominance of family salary range between 1 and 3 salaries, less than three months of breastfeeding, parents education of less than eight years and exposure to maternal and family smoking on 10 and 18 patients respectively; CHAQ average value was 0,36 and 28 patients were without disability; the JADAS average was 9.1Â11; Vitamin D average was 31,52 ng/ml, with 50% presenting sufficient levels. No relationship between JADAS levels and vitamin D was observed; significant influence of environmental factors on the clinical picture was not detected. It was concluded that vitamin D levels were sufficient in half of the patients, probably reflecting the higher secondary sun exposure to the geographical location of the state of Cearà next the equator; no correlation was found between VitD and inflammatory activity in JIA. Environmental factors did not influence the clinical presentation of JIA in this research

The Relationships Between ELM Suppression, Pedestal Profiles, and Lithium Wall Coatings in NSTX

Recently in the National Spherical Torus Experiment (NSTX), increasing lithium wall coatings suppressed edge localized modes (ELMs), gradually but not quite monotonically. This work details profile and stability analysis as ELMs disappeared throughout the lithium scan. While the quantity of lithium deposited between discharges did not uniquely determine the presence of ELMs, profile analysis demonstrated that lithium was correlated to wider density and pressure pedestals with peak gradients farther from the separatrix. Moreover, the ELMy and ELM-free discharges were cleanly separated by their density and pedestal widths and peak gradient locations. Ultimately, ELMs were only suppressed when lithium caused the density pedestal to widen and shift inward. These changes in the density gradient were directly reflected in the pressure gradient and calculated bootstrap current. This supports the theory that ELMs in NSTX are caused by peeling and/or ballooning modes, as kink/peeling modes are stabilized when the edge current and pressure gradient shift away from the separatrix. Edge stability analysis using ELITE corroborated this picture, as reconstructed equilibria from ELM-free discharges were generally farther from their kink/peeling stability boundaries than ELMy discharges. We conclude that density profile control provided by lithium is the key first step to ELM suppression in NST

Effect of progressively increasing lithium conditioning on edge transport and stability in high triangularity NSTX H-modes

A sequence of H-mode discharges with increasing levels of pre-discharge lithium evaporation (�dose�) was conducted in high triangularity and elongation boundary shape in NSTX. Energy confinement increased, and recycling decreased with increasing lithium dose, similar to a previous lithium dose scan in medium triangularity and elongation plasmas. Data-constrained SOLPS interpretive modeling quantified the edge transport change: the electron particle diffusivity decreased by 10-30x. The electron thermal diffusivity decreased by 4x just inside the top of the pedestal, but increased by up to 5x very near the separatrix. These results provide a baseline expectation for lithium benefits in NSTX-U, which is optimized for a boundary shape similar to the one in this experiment.readme and data file

The syntactic graph of a sofic shift

invariant under shift equivalenc