Ultraluminous X-ray sources (ULXs) are a population of extragalactic objects whose luminosity exceeds the Eddington limit for a 10 M black hole (BH). Their properties have been widely interpreted in ...terms of accreting stellar-mass or intermediate-mass BHs. However at least three neutron stars (NSs) have been recently identified in ULXs through the discovery of periodic pulsations. Motivated by these findings we studied the spectral properties of a sample of bright ULXs using a simple continuum model which was extensively used to fit the X-ray spectra of accreting magnetic NSs in the Galaxy. We found that such a model, consisting of a power-law with a high-energy exponential cut-off, fits most of the ULX spectra analyzed here very well, at a level comparable to that of models involving an accreting BH. On these grounds alone we suggest that other non-pulsating ULXs may host NSs. We also found that above 2 keV the spectrum of known pulsating ULXs is harder than that of the majority of the other ULXs of the sample, with only IC 342 X-1 and Ho IX X-1 displaying spectra of comparable hardness. We thus suggest that these two ULXs may host an accreting NS and encourage searches for periodic pulsations in the flux.
Abstract Aging is associated with a progressive decline in skeletal muscle mass and strength. The decline, known as sarcopenia, could lead to physical disability, poor quality of life, and death. ...Additionally, the older population usually experiences age-related muscle changes that affect muscle mass, muscular strength and functional abilities. The purpose of this review is to describe the role of protein and exercise in slowing the progression of sarcopenia. It will also discuss whether age-related changes can be attenuated by dietary protein and exercise in the older population. This review will also cover one of the possible mechanisms of how dietary protein and exercise are involved in sarcopenia prevention, as well as the available measurement tools. Based on the findings of this review, the adequate amount of protein required for older men and women needs to be revised and likely be higher. Moreover, studies are required to explore some inconclusive findings concerning sarcopenia in the older population. Further research is required to investigate the following: 1) the safety and effectiveness concerning the consumption of 1.4 g of protein/kg of body weight (or more) in this vulnerable population; 2) the effectiveness of amino acid supplementation in reducing progression of sarcopenia over time through longitudinal studies; 3) the preferred source and timing of protein for the older population to maintain muscular strength and attenuate sarcopenia; 4) exercise interventions, especially those of longer duration, in the attenuation of sarcopenia; 5) other types of exercise and their effects on age-related muscle changes; 6) the mechanism of how protein and exercise prevent muscle loss with aging; and 7) determine the best method to diagnose sarcopenia.
What does it mean to cultivate a "healthy reflection culture" in HPE? For @moniztracy1 and @StellaHPE, it means acceptance and management of “not knowing” and an explicit framing of the essence of ...being a professional practitioner; to get there, writing can help.
Background: Physical inactivity, inadequate dietary protein, and low-grade systemic inflammation contribute to age-related muscle loss, impaired function, and disability.Objective: We assessed the ...effects of progressive resistance training (PRT) combined with a protein-enriched diet facilitated through lean red meat on lean tissue mass (LTM), muscle size, strength and function, circulating inflammatory markers, blood pressure, and lipids in elderly women.Design: In a 4-mo cluster randomized controlled trial, 100 women aged 60–90 y who were residing in 15 retirement villages were allocated to receive PRT with lean red meat (∼160 g cooked) to be consumed 6 d/wk resistance training plus lean red meat (RT+Meat) group; n = 53 or control PRT 1 serving pasta or rice/d; control resistance training (CRT) group; n = 47). All women undertook PRT 2 times/wk and received 1000 IU vitamin D3/d.Results: The mean (± SD) protein intake was greater in the RT+Meat group than in the CRT group throughout the study (1.3 ± 0.3 compared with 1.1 ± 0.3 g · kg−1 · d−1, respectively; P < 0.05). The RT+Meat group experienced greater gains in total body LTM (0.45 kg; 95% CI: 0.07, 0.84 kg), leg LTM (0.22 kg; 95% CI: 0.02, 0.42 kg), and muscle strength (18%; 95% CI: 0.03, 0.34) than did the CRT group (all P < 0.05). The RT+Meat group also experienced a 10% greater increase in serum insulin-like growth factor I (P < 0.05) and a 16% greater reduction in the proinflammatory marker interleukin-6 (IL-6) (P < 0.05) after 4 mo. There were no between-group differences for the change in blood lipids or blood pressure.Conclusion: A protein-enriched diet equivalent to ∼1.3 g · kg−1 · d−1 achieved through lean red meat is safe and effective for enhancing the effects of PRT on LTM and muscle strength and reducing circulating IL-6 concentrations in elderly women. This trial was registered at the Australian Clinical Trials Registry as ACTRN12609000223235.
Context
Reflection and reflective practice have become popular topics of scholarly dialogue in medical education. This popularity has given rise to checklists, portfolios and other tools to inspire ...and document reflection. We argue that some of the common ways in which reflection has been applied are influenced by broader discourses of assessment and evidence, and divorced from original theories of reflection and reflective practice.
Methods
This paper was developed using a critical narrative approach. First we present two theoretical lenses provided by theories of reflection. Next we present a summary of relevant literature, indexed in PubMed from 2004 to 2014, relating to the application of reflection or reflective practice to undergraduate and postgraduate medical education. We categorise these articles broadly by trends and problematise the trends relative to the two theoretical lenses of reflection.
Results
Two relevant theoretical orientations of reflection for medical education are: (i) reflection as epistemology of practice, and (ii) reflection as critical social inquiry. Three prevalent trends in the application of reflection to medical education are: (i) utilitarian applications of reflection; (ii) a focus on the self as the object of reflection, and (iii) reflection and assessment. These trends align with dominant epistemological positions in medicine, but not with those that underpin reflection.
Conclusions
We argue for continued theorising of and theoretically informed applications of reflection, drawing upon epistemologies of practice and critical reflection as critical social inquiry. These directions offer medical education research broad and deep potential in theories of reflection, particularly in relation to knowledge creation within uncertain and complex situations, and challenging of dominant discourses and structures. Future work could explore how dominant epistemological positions and discourses in medicine influence theories from other disciplines when these theories are deployed in medical education.
Discuss ideas arising from the article at www.mededuc.com discuss.
As a field, health professions education (HPE) has begun to answer calls to draw on social sciences and humanities (SS&H) knowledge and approaches for curricular content, design, and pedagogy. Two ...commonly used SS&H concepts in HPE are critical reflection and critical reflexivity. But these are often conflated, misunderstood, and misapplied. Improved clarity of these concepts may positively affect both the education and practice of health professionals. Thus, the authors seek to clarify the origins of each, identify the similarities and differences between them, and delineate the types of teaching and assessment methods that fit with critical reflection and/or critical reflexivity. Common to both concepts is an ultimate goal of social improvement. Key differences include the material emphasis of critical reflection and the discursive emphasis of critical reflexivity. These similarities and differences result in some different and some similar teaching and assessment approaches, which are highlighted through examples. The authors stress that all scientific and social scientific concepts and methods imported into HPE must be subject to continued scrutiny both from within their originating disciplines and in HPE. This continued questioning is core to the ongoing development of the HPE field and also to health professionals' thinking and practice.
How superconductivity interacts with charge or nematic order is one of the great unresolved issues at the center of research in quantum materials. Ba1−xSrxNi2As2 (BSNA) is a charge ordered pnictide ...superconductor recently shown to exhibit a sixfold enhancement of superconductivity due to nematic fluctuations near a quantum phase transition (at xc = 0.7) 1. The superconductivity is, however, anomalous, with the resistive transition for 0.4 < x < xc occurring at a higher temperature than the specific heat anomaly. Using x-ray scattering, we discovered a new charge density wave (CDW) in BSNA in this composition range. The CDW is commensurate with a period of two lattice parameters, and is distinct from the two CDWs previously reported in this material 1,2. We argue that the anomalous transport behavior arises from heterogeneous superconductivity nucleating at antiphase domain walls in this CDW. We also present new data on the incommensurate CDW, previously identified as being unidirectional 2, showing that it is a rotationally symmetric "4Q" state with C4 symmetry. Our study establishes BSNA as a rare material containing three distinct CDWs, and an exciting test bed for studying coupling between CDW, nematic, and SC orders.
We present a systematic analysis of the fast time variability properties of the transient black hole binary GRO J1655−40, based on the complete set of Rossi X-ray Timing Explorer observations. We ...demonstrate that the frequencies of the quasi-periodic oscillations and of the broad-band noise components and their variations match accurately the strong field general relativistic frequencies of particle motion in the close vicinity of the innermost stable circular orbit, as predicted by the relativistic precession model.We obtain high-precision measurements of the black hole mass M = (5.31 ± 0.07) M, consistent with the value from optical/NIR observations and spin (a = 0.290 ± 0.003), through the sole use of X-ray timing.
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