1,612 research outputs found
Credentialing for radiology
Patients expect to receive safe, predictable and high-quality care delivered by competent professionals. Thus, it has become important to provide specific training in existing and new modalities and prove on-going clinical expertise. Hospital credentialing is the process by which the competence of a doctor is determined by the hospital management. In Australia, radiologists participate in a mandatory program of continuing professional development and are also required to maintain a logbook of procedures. The Conjoint Committee for the Recognition of Training in Peripheral Endovascular Therapy has been established to advise the respective subspecialty groups on the requirements for accreditation. This article examines some of the issues the committee has considered in preparing the criteria to assist institutions for the purposes of credentialing and gives an Australian perspective on future trends
Energy storage mechanisms in vacancy-ordered Wadsley-Roth layered niobates
Wadsley–Roth (WR) crystallographic shear structures demonstrate high energy and power densities as Li-ion battery anode materials. We report the (de)lithiation behavior of two WR-derived layered niobates: NaNb_{3}O_{8} and KNb_{3}O_{8}. Both demonstrate multi-electron (Nb5+/Nb3+) redox on the first discharge, reacting with ≈5 mol Li per mol ANb_{3}O_{8}. Li intercalation in NaNb_{3}O_{8} is dominated by Li-diffusion kinetics and evolution of the interlayer structure, with Li initially filling octahedral sites near the interlayer space to draw the layers together to form a (2 × 2)_{∞} WR structure. This average structure change pushes Na ions into the square channels, blocking fast Li diffusion down the square channels that provide the fast Li-ion conduction in most WR materials. Upon charge, Li ions incorporated into the octahedral WR sites (ordered vacancies in the layered structure) are extracted, revealing a new, reversible Li site for additional capacity in WR-like materials. The behavior of KNb_{3}O_{8} is similar, but has additional hysteresis associated with its larger counter-cation. While neither layered niobate matches the demonstrated performance of WR materials, by studying them, we identify a route for increased capacity in WR-like frameworks. Additionally, we identify the important role of Li diffusion kinetics and counter-cations in the cycling behavior of WR-derived structures
Subtidal macrozoobenthos communities from northern Chile during and post El Niño 1997–1998
Despite a large amount of climatic and oceanographic information dealing with the recurring climate phenomenon El Niño (EN) and its well known impact on diversity of marine benthic communities, most published data are rather descriptive and consequently our understanding of the underlying mechanisms and processes that drive community structure during EN are still very scarce. In this study, we address two questions on the effects of EN on macrozoobenthic communities: (1) how does EN affect species diversity of the communities in northern Chile? and (2) is EN a phenomenon that restarts community assembling processes by affecting species interactions in northern Chile? To answer these questions, we compared species diversity and co-occurrence patterns of soft-bottoms macrozoobenthos communities from the continental shelf off northern Chile during (March 1998) and after (September 1998) the strong EN event 1997–1998. The methods used varied from species diversity and species co-occurrence analyses to multivariate ordination methods.
Our results indicate that EN positively affects diversity of macrozoobenthos communities in the study area, increasing the species richness and diversity and decreasing the species dominance. EN represents a strong disturbance that affects species interactions that rule the species assembling processes in shallow-water, sea-bottom environments
Explanation and elaboration of the Standards for UNiversal reporting of patient Decision Aid Evaluations (SUNDAE) guidelines: examples of reporting SUNDAE items from patient decision aid evaluation literature
This Explanation and Elaboration (E&E) article expands on the 26 items in the Standards for UNiversal reporting of Decision Aid Evaluations (SUNDAE) guidelines. The E&E provides a rationale for each item and includes examples for how each item has been reported in published papers evaluating patient decision aids. The Explanation and Elaboration focuses on items key to reporting studies evaluating patient decision aids and is intended to be illustrative rather than restrictive. Authors and reviewers may wish to use the Explanation and Elaboration broadly to inform structuring of patient decision aid evaluation reports, or use it as a reference to obtain details about how to report individual Checklist items
Standards for UNiversal reporting of patient Decision Aid Evaluation studies: the development of SUNDAE Checklist
Background: Patient decision aids (PDAs) are evidence-based tools designed to help patients make specific and deliberated choices among healthcare options. The International Patient Decision Aid Standards (IPDAS) Collaboration review papers and Cochrane systematic review of PDAs have found significant gaps in the reporting of evaluations of PDAs, including poor or limited reporting of PDA content, development methods, and delivery. This study sought to develop and reach consensus on reporting guidelines to improve the quality of publications evaluating PDAs.
Methods: An international workgroup, consisting of members from IPDAS Collaboration, followed established methods to develop reporting guidelines for PDA evaluation studies. This paper describes the results from three completed phases (1) Planning, (2) Drafting, and (3) Consensus, which included a modified, two stage, online international Delphi process. The work was conducted over two years with bi-monthly conference calls and three in-person meetings. The workgroup used input from these phases to produce a final set of recommended items in the form of a checklist.
Results: The SUNDAE Checklist (Standards for UNiversal reporting of patient Decision Aid Evaluations) includes 26 items recommended for studies reporting evaluations of PDAs. In the two-stage Delphi process, 117/143 (82%) experts from 14 countries completed round 1 and 96/117 (82%) completed round 2. Respondents reached a high level of consensus on the importance of the items and indicated strong willingness to use the items when reporting PDA studies.
Conclusion: The SUNDAE Checklist will help ensure that reports of PDA evaluation studies are understandable, transparent, and of high quality. A separate Explanation and Elaboration publication provides additional details to support use of the Checklist
The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)
The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans
Taxonomic Distinctness of Demersal Fishes of the California Current: Moving Beyond Simple Measures of Diversity for Marine Ecosystem-Based Management
BACKGROUND: Large-scale patterns or trends in species diversity have long interested ecologists. The classic pattern is for diversity (e.g., species richness) to decrease with increasing latitude. Taxonomic distinctness is a diversity measure based on the relatedness of the species within a sample. Here we examined patterns of taxonomic distinctness in relation to latitude (ca. 32-48 degrees N) and depth (ca. 50-1220 m) for demersal fishes on the continental shelf and slope of the US Pacific coast. METHODOLOGY/PRINCIPAL FINDINGS: Both average taxonomic distinctness (AvTD) and variation in taxonomic distinctness (VarTD) changed with latitude and depth. AvTD was highest at approximately 500 m and lowest at around 200 m bottom depth. Latitudinal trends in AvTD were somewhat weaker and were depth-specific. AvTD increased with latitude on the shelf (50-150 m) but tended to decrease with latitude at deeper depths. Variation in taxonomic distinctness (VarTD) was highest around 300 m. As with AvTD, latitudinal trends in VarTD were depth-specific. On the shelf (50-150 m), VarTD increased with latitude, while in deeper areas the patterns were more complex. Closer inspection of the data showed that the number and distribution of species within the class Chondrichthyes were the primary drivers of the overall patterns seen in AvTD and VarTD, while the relatedness and distribution of species in the order Scorpaeniformes appeared to cause the relatively low observed values of AvTD at around 200 m. CONCLUSIONS/SIGNIFICANCE: These trends contrast to some extent the patterns seen in earlier studies for species richness and evenness in demersal fishes along this coast and add to our understanding of diversity of the demersal fishes of the California Current
Doppler findings in a rare Coronary Artery Fistula
One of the primary forms of congenital anomalies of the coronary arteries is coronary artery fistula (CAF). It is defined as a direct communication between the coronary artery and any surrounding cardiac chamber or vascular structure, which bypasses the myocardial capillary bed. We present a newborn baby with a large coronary artery fistula connecting the left anterior descending (LAD) artery to the left ventricular (LV) apex. Associated cardiac abnormalities were found: a ventricular septal defect (diameter 4 mm), a patent foramen ovale as well as trivial tricuspid and mitral regurgitation. Here we demonstrate the echocardiograms of an extremely rare form of CAF diagnosed within the first days of postnatal life
Anyonic interferometry and protected memories in atomic spin lattices
Strongly correlated quantum systems can exhibit exotic behavior called
topological order which is characterized by non-local correlations that depend
on the system topology. Such systems can exhibit remarkable phenomena such as
quasi-particles with anyonic statistics and have been proposed as candidates
for naturally fault-tolerant quantum computation. Despite these remarkable
properties, anyons have never been observed in nature directly. Here we
describe how to unambiguously detect and characterize such states in recently
proposed spin lattice realizations using ultra-cold atoms or molecules trapped
in an optical lattice. We propose an experimentally feasible technique to
access non-local degrees of freedom by performing global operations on trapped
spins mediated by an optical cavity mode. We show how to reliably read and
write topologically protected quantum memory using an atomic or photonic qubit.
Furthermore, our technique can be used to probe statistics and dynamics of
anyonic excitations.Comment: 14 pages, 6 figure
What traits are carried on mobile genetic elements, and why?
Although similar to any other organism, prokaryotes can transfer genes vertically from mother cell to daughter cell, they can also exchange certain genes horizontally. Genes can move within and between genomes at fast rates because of mobile genetic elements (MGEs). Although mobile elements are fundamentally self-interested entities, and thus replicate for their own gain, they frequently carry genes beneficial for their hosts and/or the neighbours of their hosts. Many genes that are carried by mobile elements code for traits that are expressed outside of the cell. Such traits are involved in bacterial sociality, such as the production of public goods, which benefit a cell's neighbours, or the production of bacteriocins, which harm a cell's neighbours. In this study we review the patterns that are emerging in the types of genes carried by mobile elements, and discuss the evolutionary and ecological conditions under which mobile elements evolve to carry their peculiar mix of parasitic, beneficial and cooperative genes
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