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

A systematic review of the effects of exercise interventions on body composition in HIV+ adults

Over the years, physical activity and exercise have been used to positively impact the health and quality of life of persons infected with HIV and, more recently, has been associated with a spectrum of body composition changes. The aim of this review was to examine the effects of various exercise interventions on body composition in HIV positive adults, using a search strategy of randomized, controlled trials (RCTs). A systematic review was performed by five independent reviewers using a predetermined protocol adapted from previous research for assessing the articles for inclusion, the extracted data, and methodological quality. Eight RCTs involving 430 (26% female) HIV positive adults performing exercise a minimum of thrice weekly for at least six weeks were finally selected: Four were progressive resistance training (PRT) studies, three were aerobic training (AT) studies, and one involved yoga. In the PRT studies, there were significant increases in three anthropometric measures, namely, body mass, sum of skinfolds and sum of limb girths. In the AT studies, significant decreases were found in seven anthropometric measures, namely, body mass index, waist-hip ratio, body mass, triceps skinfold, waist circumference and sum of skinfolds. With yoga, the changes were nonsignificant. Exercise contributes to improved body composition and, when applied safely, appears to be beneficial for adults living with HIV/AIDS. However, these findings should be interpreted cautiously due to the relatively few RCTs published to date. Future studies would benefit from increased attention to sample size, female participants, participant follow-up, complete statistical analysis and intention-to-treat analysis.Scopu

Dust in Supernovae and Supernova Remnants I : Formation Scenarios

Supernovae are considered as prime sources of dust in space. Observations of local supernovae over the past couple of decades have detected the presence of dust in supernova ejecta. The reddening of the high redshift quasars also indicate the presence of large masses of dust in early galaxies. Considering the top heavy IMF in the early galaxies, supernovae are assumed to be the major contributor to these large amounts of dust. However, the composition and morphology of dust grains formed in a supernova ejecta is yet to be understood with clarity. Moreover, the dust masses inferred from observations in mid-infrared and submillimeter wavelength regimes differ by two orders of magnitude or more. Therefore, the mechanism responsible for the synthesis of molecules and dust in such environments plays a crucial role in studying the evolution of cosmic dust in galaxies. This review summarises our current knowledge of dust formation in supernova ejecta and tries to quantify the role of supernovae as dust producers in a galaxy.Peer reviewe

The use of antibiotic-loaded bone cement and systemic antibiotic prophylactic use in 2,971,357 primary total knee arthroplasties from 2010 to 2020: an international register-based observational study among countries in Africa, Europe, North America, and Oceania

Background and purpose - Antibiotic-loaded bone cement (ALBC) and systemic antibiotic prophylaxis (SAP) have been used to reduce periprosthetic joint infection (PJI) rates. We investigated the use of ALBC and SAP in primary total knee arthroplasty (TKA).Patients and methods - This observational study is based on 2,971,357 primary TKAs reported in 2010-2020 to national/regional joint arthroplasty registries in Australia, Den-mark, Finland, Germany, Italy, the Netherlands, New Zealand, Norway, Romania, South Africa, Sweden, Switzerland, the UK, and the USA. Aggregate-level data on trends and types of bone cement, antibiotic agents, and doses and duration of SAP used was extracted from participating registries.Results - ALBC was used in 77% of the TKAs with variation ranging from 100% in Norway to 31% in the USA. Palacos R+G was the most common (62%) ALBC type used. The primary antibiotic used in ALBC was gentamicin (94%). Use of ALBC in combination with SAP was common prac-tice (77%). Cefazolin was the most common (32%) SAP agent. The doses and duration of SAP used varied from one single preoperative dosage as standard practice in Bolzano, Italy (98%) to 1-day 4 doses in Norway (83% of the 40,709 TKAs reported to the Norwegian arthroplasty register). Conclusion - The proportion of ALBC usage in pri-mary TKA varies internationally, with gentamicin being the most common antibiotic. ALBC in combination with SAP was common practice, with cefazolin the most common SAP agent. The type of ALBC and type, dose, and duration of SAP varied among participating countries.Orthopaedics, Trauma Surgery and Rehabilitatio

Polarimetric line profiles for scattering off rotating disks

Peer reviewe

Linear Line Polarimetry Modelling of Pre-main Sequence Stars

Original paper can be found at: http://www.aspbooks.org/ Copyright ASPWe present emission line polarimetry data and modelling relevant to the circumstellar geometry and kinematics around pre-main sequence stars. For a sample of both Herbig Ae/Be stars and T Tauri stars, we find that most show polarization changes across H®, implying that flattened structures are common on the smallest scales { and over a range of stellar masses. We also present Monte Carlo calculations of spectral line profiles scattered in rotating accretion disks. We consider the case of a central star that emits line photons uniformly, as well as via hot spots. Intriguingly, the switch between a uniform point source and a finite-sized star results in a marked difference in the position angle variation across the line. Our models demonstrate the diagnostic potential of line polarimetry in determining the disk inclination and the size of the inner hole { a spatial scale no other technique currently accesses

Linear Spectropolarimetry of Young and Other Emission Line Stars

Peer reviewe

RECENT PROGRESS IN INFRARED AND MICROWAVE ATMOSPHERIC SOUNDING

No abstract availabl