6,389 research outputs found
Analysis of residues resulting from mafic silicate impacts into aluminium 1100
Accepted versio
Beyond capitalism and liberal democracy: on the relevance of GDH Cole’s sociological critique and alternative
This article argues for a return to the social thought of the often ignored early 20th-century English thinker GDH Cole. The authors contend that Cole combined a sociological critique of capitalism and liberal democracy with a well-developed alternative in his work on guild socialism bearing particular relevance to advanced capitalist societies. Both of these, with their focus on the limitations on ‘free communal service’ in associations and the inability of capitalism to yield emancipation in either production or consumption, are relevant to social theorists looking to understand, critique and contribute to the subversion of neoliberalism. Therefore, the authors suggest that Cole’s associational sociology, and the invitation it provides to think of formations beyond capitalism and liberal democracy, is a timely and valuable resource which should be returned to
Killing spinor data on distorted black hole horizons and the uniqueness of stationary vacuum black holes
We make use of the black hole holograph construction of [I. R\'acz,
Stationary black holes as holographs, Class. Quantum Grav. 31, 035006 (2014)]
to analyse the existence of Killing spinors in the domain of dependence of the
horizons of distorted black holes. In particular, we provide conditions on the
bifurcation sphere ensuring the existence of a Killing spinor. These conditions
can be understood as restrictions on the curvature of the bifurcation sphere
and ensure the existence of an axial Killing vector on the 2-surface. We obtain
the most general 2-dimensional metric on the bifurcation sphere for which these
curvature conditions are satisfied. Remarkably, these conditions are found to
be so restrictive that, in the considered particular case, the free data on the
bifurcation surface (determining a distorted black hole spacetime) is
completely determined by them. In addition, we formulate further conditions on
the bifurcation sphere ensuring that the Killing vector associated to the
Killing spinor is Hermitian. Once the existence of a Hermitian Killing vector
is guaranteed, one can use a characterisation of the Kerr spacetime due to Mars
to identify the particular subfamily of 2-metrics giving rise to a member of
the Kerr family in the black hole holograph construction. Our analysis sheds
light on the role of asymptotic flatness and curvature conditions on the
bifurcation sphere in the context of the problem of uniqueness of stationary
black holes. The Petrov type of the considered distorted black hole spacetimes
is also determined.Comment: 39 pages, 1 figur
Discrepancies in autologous bone marrow stem cell trials and enhancement of ejection fraction (DAMASCENE): weighted regression and meta-analysis
Objective To investigate whether discrepancies in trials of use of bone marrow stem cells in patients with heart disease account for the variation in reported effect size in improvement of left ventricular function. Design Identification and counting of factual discrepancies in trial reports, and sample size weighted regression against therapeutic effect size. Meta-analysis of trials that provided sufficient information. Data sources PubMed and Embase from inception to April 2013. Eligibility for selecting studies Randomised controlled trials evaluating the effect of autologous bone marrow stem cells for heart disease on mean left ventricular ejection fraction. Results There were over 600 discrepancies in 133 reports from 49 trials. There was a significant association between the number of discrepancies and the reported increment in EF with bone marrow stem cell therapy (Spearman’s r=0.4, P=0.005). Trials with no discrepancies were a small minority (five trials) and showed a mean EF effect size of −0.4%. The 24 trials with 1-10 discrepancies showed a mean effect size of 2.1%. The 12 with 11-20 discrepancies showed a mean effect of size 3.0%. The three with 21-30 discrepancies showed a mean effect size of 5.7%. The high discrepancy group, comprising five trials with over 30 discrepancies each, showed a mean effect size of 7.7%. Conclusions Avoiding discrepancies is difficult but is important because discrepancy count is related to effect size. The mechanism is unknown but should be explored in the design of future trials because in the five trials without discrepancies the effect of bone marrow stem cell therapy on ejection fraction is zero
Distributed Computing in the Asynchronous LOCAL model
The LOCAL model is among the main models for studying locality in the
framework of distributed network computing. This model is however subject to
pertinent criticisms, including the facts that all nodes wake up
simultaneously, perform in lock steps, and are failure-free. We show that
relaxing these hypotheses to some extent does not hurt local computing. In
particular, we show that, for any construction task associated to a locally
checkable labeling (LCL), if is solvable in rounds in the LOCAL model,
then remains solvable in rounds in the asynchronous LOCAL model.
This improves the result by Casta\~neda et al. [SSS 2016], which was restricted
to 3-coloring the rings. More generally, the main contribution of this paper is
to show that, perhaps surprisingly, asynchrony and failures in the computations
do not restrict the power of the LOCAL model, as long as the communications
remain synchronous and failure-free
A small-scale, portable method for extracting microplastics from marine sediments
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Cheap, effective method for microplastic extraction from sediments.
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High, reproducible recovery rates - 95.8%.
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Comparison of three commonly used floatation media.
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Zinc chloride (1.5 g cm−3) deemed an effective floatation medium.
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Method applied to environmental samples across a range of sediment types
Abundance and properties of microplastics found in commercial fish meal and cultured common carp (Cyprinus carpio)
Microplastics (MPs) are environmental contaminants that are of increasing global concern. This study investigated the presence of MPs in four varieties of marine-derived commercial fish meal, followed by identification of their polymer composition using Fourier transform infrared (FTIR) spectroscopy. Exposure experiments were conducted on cultured common carp (Cyprinus carpio) by feeding four varieties of commercially available fish meal to determine relationships between abundance and properties of MPs found both in meal and in those transferred to cultured common carp. Mean particle sizes were 452 ± 161 μm (± SD). Fragments were the predominant shape of MP found in fish meal (67%) and C. carpio gastrointestinal tract and gills (65%), and polypropylene and polystyrene were the most present plastic polymers found in fish meal (45% and 24%, respectively) and C. carpio (37% and 33%, respectively). Positive relationships were found between MP levels in fish meal and C. carpio. This study highlights that marine-derived fish meal may be a source of MPs which can be transferred to cultured fish, thus posing a concern for aquaculture
A meta-analysis of structural MRI studies of the brain in systemic lupus erythematosus (SLE)
A comprehensive search of published literature in brain volumetry was conducted in three autoimmune diseases — systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and ulcerative colitis (UC) — with the intention of performing a meta-analysis of published data. Due to the lack of data in RA and UC, the reported meta-analysis was limited to SLE. The MEDLINE database was searched for studies from 1988 to March 2022. A total of 175 papers met the initial inclusion criteria, and 16 were included in a random-effects meta-analysis. The reduction in the number of papers included in the final analysis is primarily due to the lack of overlap in measured and reported brain regions. A significantly lower volume was seen in patients with SLE in the hippocampus, corpus callosum, and total gray matter volume measurements as compared to age- and sex-matched controls. There were not enough studies to perform a meta-analysis for RA and UC; instead, we include a summary of published volumetric studies. The meta-analyses revealed structural brain abnormalities in patients with SLE, suggesting that lower global brain volumes are associated with disease status. This volumetric difference was seen in both the hippocampus and corpus callosum and total gray matter volume measurements. These results indicate both gray and white matter involvements in SLE and suggest there may be both localized and global reductions in brain volume
Randomised crossover trial of rate feedback and force during chest compressions for paediatric cardiopulmonary resuscitation
Objective: To determine the effect of visual feedback on rate of chest compressions, secondarily relating the forces used. / Design: Randomised crossover trial. / Setting: Tertiary teaching hospital. / Subjects: Fifty trained hospital staff. / Interventions: A thin sensor-mat placed over the manikin's chest measured rate and force. Rescuers applied compressions to the same paediatric manikin for two sessions. During one session they received visual feedback comparing their real-time rate with published guidelines. / Outcome measures: Primary: compression rate. Secondary: compression and residual forces. / Results: Rate of chest compressions (compressions per minute (compressions per minute; cpm)) varied widely (mean (SD) 111 (13), range 89–168), with a fourfold difference in variation during session 1 between those receiving and not receiving feedback (108 (5) vs 120 (20)). The interaction of session by feedback order was highly significant, indicating that this difference in mean rate between sessions was 14 cpm less (95% CI −22 to −5, p=0.002) in those given feedback first compared with those given it second. Compression force (N) varied widely (mean (SD) 306 (94); range 142–769). Those receiving feedback second (as opposed to first) used significantly lower force (adjusted mean difference −80 (95% CI −128 to −32), p=0.002). Mean residual force (18 N, SD 12, range 0–49) was unaffected by the intervention. / Conclusions: While visual feedback restricted excessive compression rates to within the prescribed range, applied force remained widely variable. The forces required may differ with growth, but such variation treating one manikin is alarming. Feedback technologies additionally measuring force (effort) could help to standardise and define effective treatments throughout childhood
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