Accretion, Outflows, and Winds of Magnetized Stars

Many types of stars have strong magnetic fields that can dynamically influence the flow of circumstellar matter. In stars with accretion disks, the stellar magnetic field can truncate the inner disk and determine the paths that matter can take to flow onto the star. These paths are different in stars with different magnetospheres and periods of rotation. External field lines of the magnetosphere may inflate and produce favorable conditions for outflows from the disk-magnetosphere boundary. Outflows can be particularly strong in the propeller regime, wherein a star rotates more rapidly than the inner disk. Outflows may also form at the disk-magnetosphere boundary of slowly rotating stars, if the magnetosphere is compressed by the accreting matter. In isolated, strongly magnetized stars, the magnetic field can influence formation and/or propagation of stellar wind outflows. Winds from low-mass, solar-type stars may be either thermally or magnetically driven, while winds from massive, luminous O and B type stars are radiatively driven. In all of these cases, the magnetic field influences matter flow from the stars and determines many observational properties. In this chapter we review recent studies of accretion, outflows, and winds of magnetized stars with a focus on three main topics: (1) accretion onto magnetized stars; (2) outflows from the disk-magnetosphere boundary; and (3) winds from isolated massive magnetized stars. We show results obtained from global magnetohydrodynamic simulations and, in a number of cases compare global simulations with observations.Comment: 60 pages, 44 figure

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

Effect of flow rate, humidifier dome and water volume on maximising heated, humidified gas use for neonatal resuscitation

Aim: Dry, cold gas is used for neonatal resuscitation, contributing to low admission temperatures and exacerbation of lung injury. Recently, a method of heating and humidifying neonatal resuscitation gases has become available. We aimed to determine the optimal flow rate, humidifier chamber and water volume needed to reach 36. °C, and near 100% humidity at the patient T-piece in the shortest possible time. Method: A T-piece resuscitator was connected via a heated patient circuit to a humidifier chamber. Trials were performed using different gas flow rates (6, 8 and 10. L/min), humidification chambers (MR290, MR225) and water volumes (30. g, 108. g). Temperature was recorded at the humidifier chamber (T1), distal temperature probe (T2) and the T-piece (T3) over a 20. min period at 30. s intervals. A test lung was added during one trial. Results: No significant difference existed between flow rates 8. L/min and 10. L/min (p= 0.091, p= 0.631). T3 reached 36. °C and remained stable at 360. s (8. L/min, MR225, 30. mL); near 100% RH was reached at 107. s (10. L/min, MR225, 30. mL). T3 and humidity reached and remained stable at 480. s (10. L/min, MR290, 30. mL). Target temperature and humidity was not reached with the test lung. Conclusions: It is possible to deliver heated, humidified gases in neonatal resuscitation in a clinically acceptable timeframe. We suggest the set-up to achieve optimal temperature and humidity for resuscitation purposes is 10. L/min of gas flow, a MR290 humidification chamber, and 30. mL of water

Neonatal consultation at a distance

Background: Infant transport can be costly, time consuming and risky for both the infant and transport-team. For some infants, telemedicine may improve care, avoid transport and save money. Methods: We conducted an informal retrospective review of the first 10 telemedicine consultations provided from a tertiary perinatal centre to four referring hospitals. Sessions were recorded to allow evaluation of the content of each consultation. Cases of avoided transport were identified by analysis of the recordings and by interviewing the clinicians involved in the consultations. Potential savings resulting from avoided retrievals was estimated in Australian Dollars (AUD) at 2009 prices (AUD 1GUSD0Æ86). Results: Nine consultations were led by a consultant neonatologist and one by a senior registrar. In all cases a paediatrician attended at the referring sites. During sessions, visual information included radiological images (n = 7); infant observation (n = 7); viewing of the patient monitor (n = 2) and ventilator (n = 2). Telemedicine was used to manage requests for infant retrieval (n = 4) and requests for a second opinion (n = 6). This resulted in transport to the RBWH (n = 2), another intensive care nursery (n = 1) and prevented retrieval (n = 3). The total estimated saving from avoided retrievals was $23 618 (Table 1). Conclusion: These early results suggest that neonatal teleconsultation is effective. Anecdotally, the visual information increased safety and confidence in the formulation of local management plans. An infant may be managed in their own community, avoiding costly and risky transport to a tertiary facility using teleconsultation. Further research will formally assess the clinical and economic benefits over a longer time period

Granular computing based on rough sets, quotient space theory, and belief functions

A model of granular computing (GrC) is proposed by reformulating, re-interpreting, and combining results from rough sets, quotient space theory, and belief functions. Two operations, called zoomingin and zooming-out operations, are used to study connections between the elements of a universe and the elements of a granulated universe, as well as connections between computations in the two universes. The operations are studied with respect to multi-level granulation structures

A Partition Model of Granular Computing

There are two objectives of this chapter. One objective is to examine the basic principles and issues of granular computing. We focus on the tasks of granulation and computing with granules. From semantic and algorithmic perspectives, we study the construction, interpretation, and representation of granules, as well as principles and operations of computing and reasoning with granules. The other objective is to study a partition model of granular computing in a set-theoretic setting. The model is based on the assumption that a finite set of universe is granulated through a family of pairwise disjoint subsets. A hierarchy of granulations is modeled by the notion of the partition lattice