This paper presents the design, analysis, prototype, and testing of a new fault tolerant electrical drive topology. The segmented rotor switched reluctance machine (S-SRM) has been modified to ...include permanent magnet assist by placing magnets in the stator slot opening. This introduces a magnetic bias which extends the magnetic operating region of the machine and results in greater torque when compared to the conventional fault tolerant segmental rotor switched reluctance machine. This new torque dense, fault tolerant topology was investigated using 2-D (two-dimensional) and 3-DFE methods and a prototype machine built, tested and verified against the simulations. Experimental testing was carried out with and without the magnets to assess the effect of the PM assist on torque performance. Static tests were carried out to obtain the torque-flux linkage-angle waveforms and then this information used to tune a bespoke drive and test the system under dynamic conditions. The superior fault tolerant performance of this PMA S-SRM topology is highlighted by measurements taken under phase open and short circuit fault conditions. The tests show that this fault-tolerant topology not only meets the mass requirements of the aerospace application, set originally by a PMSM, but also, with the magnets now placed on the stator the rotational induced EMFs and associated short circuit currents during a fault are drastically reduced. Hence the fault tolerance of this topology is an improvement on the PMSM topology, and it will be of benefit to fault critical systems such as aerospace drives and actuators.
Overviews of systematic reviews (SRs) attempt to systematically retrieve and summarise the results of multiple systematic reviews. This is the second of two papers from a study aiming to develop a ...comprehensive evidence map of the methods used in overviews. Our objectives were to (a) develop a framework of methods for conducting, interpreting and reporting overviews (stage I)-the Methods for Overviews of Reviews (MOoR) framework-and (b) to create an evidence map by mapping studies that have evaluated overview methods to the framework (stage II). In the first paper, we reported findings for the four initial steps of an overview (specification of purpose, objectives and scope; eligibility criteria; search methods; data extraction). In this paper, we report the remaining steps: assessing risk of bias; synthesis, presentation and summary of the findings; and assessing certainty of the evidence arising from the overview.
In stage I, we identified cross-sectional studies, guidance documents and commentaries that described methods proposed for, or used in, overviews. Based on these studies, we developed a framework of possible methods for overviews, categorised by the steps in conducting an overview. Multiple iterations of the framework were discussed and refined by all authors. In stage II, we identified studies evaluating methods and mapped these evaluations to the framework.
Forty-two stage I studies described methods relevant to one or more of the latter steps of an overview. Six studies evaluating methods were included in stage II. These mapped to steps involving (i) the assessment of risk of bias (RoB) in SRs (two SRs and three primary studies, all reporting evaluation of RoB tools) and (ii) the synthesis, presentation and summary of the findings (one primary study evaluating methods for measuring overlap).
Many methods have been described for use in the latter steps in conducting an overview; however, evaluation and guidance for applying these methods is sparse. The exception is RoB assessment, for which a multitude of tools exist-several with sufficient evaluation and guidance to recommend their use. Evaluation of other methods is required to provide a comprehensive evidence map.
► Examines how different types of work experience affect informal job matching. ► Increased experience in closely related occupations facilitates informal job changes. ► Experience only matters for ...men and only for informal recruitment (not searching). ► The result suggests that experience fosters connections as well as skills. ► The social benefits of experience do not accrue to women as they do for men.
While work experience is generally seen as an indicator of human capital, it may also reflect the accumulation of social capital. This study examines how work experience facilitates informal access to employment—that is, being matched with a new employer through an informal search or informal recruitment through the non-search process (without engaging in a job search). Results from fixed effects regression on panel data from the NLSY show that experience is related to informal entry into new jobs, though in a very specific way. The odds of being informally recruited into a new job improve as work experience in related occupations rises, but this relationship holds only among men. These findings highlight the social benefits of occupation-specific work experience that accrue to men but not to women, suggesting an alternative explanation for the gender disparity in wage returns to experience.
Overviews of systematic reviews attempt to systematically retrieve and summarise the results of multiple systematic reviews. Methods for conducting, interpreting and reporting overviews are in their ...infancy. To date, there has been no evidence map of the methods used in overviews, thus making it difficult to determine the gaps and priorities for methods research. Our objectives were to develop and populate a comprehensive framework of methods for conducting, interpreting and reporting overviews (stage I) and to create an evidence map by mapping studies that have evaluated overview methods to the framework (stage II).
We searched methods collections (e.g. Cochrane Methodology Register, Meth4ReSyn library, AHRQ Effective Health Care Program) to identify eligible studies for both stages of this research. In stage I, cross-sectional studies, guidance documents and commentaries that described methods proposed for, or used in, overviews were used to develop and populate the framework of methods. Drafts and multiple iterations of the framework were discussed and refined by all authors. In stage II, we identified and described studies evaluating overview methods and mapped these evaluations to the framework.
In this paper, we present results for the four initial steps of conducting an overview: (a) specification of the purpose, objectives and scope, (b) specification of the eligibility criteria, (c) search methods and (d) data extraction. Twenty-nine studies mentioned or described methods relevant to one or more of these steps. In the developed framework, identified methods and approaches were grouped according to the steps an overview author would need to undertake. Fifteen studies evaluated identified methods, all of which mapped to the search methods step. These studies either reported the development and evaluation of a new search filter to retrieve systematic reviews or compared the performance of multiple filters.
Gaps in the evaluation of methods were found for the majority of steps in the framework. More empirical studies are needed to evaluate the methods outlined and provide a comprehensive evidence map. The framework is useful for planning these evaluations and for planning methods required to deal with challenges that arise when conducting an overview.
Introduction
The Australian National COVID‐19 Clinical Evidence Taskforce was established in March 2020 to maintain up‐to‐date recommendations for the treatment of people with coronavirus disease ...2019 (COVID‐19). The original guideline (April 2020) has been continuously updated and expanded from nine to 176 recommendations, facilitated by the rapid identification, appraisal, and analysis of clinical trial findings and subsequent review by expert panels.
Main recommendations
In this article, we describe the recommendations for treating non‐pregnant adults with COVID‐19, as current on 1 August 2022 (version 61.0). The Taskforce has made specific recommendations for adults with severe/critical or mild disease, including definitions of disease severity, recommendations for therapy, COVID‐19 prophylaxis, respiratory support, and supportive care.
Changes in management as a result of the guideline
The Taskforce currently recommends eight drug treatments for people with COVID‐19 who do not require supplemental oxygen (inhaled corticosteroids, casirivimab/imdevimab, molnupiravir, nirmatrelvir/ritonavir, regdanvimab, remdesivir, sotrovimab, tixagevimab/cilgavimab) and six for those who require supplemental oxygen (systemic corticosteroids, remdesivir, tocilizumab, sarilumab, baricitinib, casirivimab/imdevimab). Based on evidence of their achieving no or only limited benefit, ten drug treatments or treatment combinations are not recommended; an additional 42 drug treatments should only be used in the context of randomised trials. Additional recommendations include support for the use of continuous positive airway pressure, prone positioning, and endotracheal intubation in patients whose condition is deteriorating, and prophylactic anticoagulation for preventing venous thromboembolism. The latest updates and full recommendations are available at www.covid19evidence.net.au.
► Uses nationally representative data to examine unequal access to network resources. ► People in white male networks receive twice as many job leads as people in female/minority networks. ► White ...male networks have higher status alters than female/minority networks. ► Gender homophilous connections are more likely to vouch for others than heterophilous ties. ► Highlights the informal barriers faced by women and racial minorities in the labor market.
Network processes have long been implicated in the reproduction of labor market inequality, but it remains unclear whether white male networks provide more social capital resources than female and minority networks. Analysis of nationally representative survey data reveals that people in white male networks receive twice as many job leads as people in female/minority networks. White male networks are also comprised of higher status connections than female/minority networks. The information and status benefits of membership in these old boy networks accrue to all respondents and not just white men. Furthermore, gender homophilous contacts offer greater job finding assistance than other contacts. The results specify how social capital flows through gendered and racialized networks.
"Living guidelines" are guidelines which are continually kept up to date as new evidence emerges. Living guideline methods are evolving. The aim of this study was to determine how frequently searches ...for new evidence should be undertaken for the Australian Living Stroke Guidelines. Members of the Living Stroke Guidelines Development Group were invited to complete an online survey. Participants nominated one or more recommendation topics from the Living Stroke Guidelines with which they had been involved and answered questions about that topic, assessing whether it met criteria for living evidence synthesis, and how frequently searches for new evidence should be undertaken and why. For each topic we also determined how many studies had been assessed and included, and whether recommendations had been changed. Fifty-seven assessments were received from 33 respondents, covering half of the 88 guideline topic areas. Nearly all assessments (49, 86%) were that the continual updating process should be maintained. Only three assessments (5%) deemed that searches should be conducted monthly; 3-monthly (14, 25%), 6-monthly (13, 23%) and yearly (17, 30%) searches were far more frequently recommended. Rarely (9, 16%) were topics deemed to meet all three criteria for living review. The vast majority of assessments (45, 79%) deemed the topic a priority for decision-making. Nearly half indicated that there was uncertainty in the available evidence or that new evidence was likely to be available soon. Our study found that participants felt that the vast majority of topics assessed in the Living Stroke Guidelines should be continually updated. However, only a fifth of topic areas were assessed as conclusively meeting all three criteria for living review, and the definition of "continual" differed widely. This work has informed decisions about search frequency for the Living Stroke Guidelines and form the basis of further research on methods for frequent updating of guidelines.
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We aimed to assess evidence of long-term effects of exposure to radiofrequency (RF) electromagnetic fields (EMF) on indicators of cognition, including domains of learning and memory, ...executive function, complex attention, language, perceptual motor ability and social cognition, and of an exposure–response relationship between RF-EMF and cognition.
We searched PubMed, Embase, PsycInfo and the EMF-Portal on September 30, 2022 without limiting by date or language of publication. We included cohort or case-control studies that evaluated the effects of RF exposure on cognitive function in one or more of the cognitive domains. Studies were rated for risk of bias using the OHAT tool and synthesised using fixed effects meta-analysis. We assessed the certainty of the evidence using the GRADE approach and considered modification by OHAT for assessing evidence of exposures.
We included 5 studies that reported analyses of data from 4 cohorts with 4639 participants consisting of 2808 adults and 1831 children across three countries (Australia, Singapore and Switzerland) conducted between 2006 and 2017. The main source of RF-EMF exposure was mobile (cell) phone use measured as calls per week or minutes per day.
For mobile phone use in children, two studies (615 participants) that compared an increase in mobile phone use to a decrease or no change were included in meta-analyses. Learning and memory. There was little effect on accuracy (mean difference, MD −0.03; 95% CI −0.07 to 0.02) or response time (MD −0.01; 95% CI −0.04 to 0.02) on the one-back memory task; and accuracy (MD −0.02; 95%CI −0.04 to 0.00) or response time (MD −0.01; 95%CI −0.04 to 0.03) on the one card learning task (low certainty evidence for all outcomes). Executive function. There was little to no effect on the Stroop test for the time ratio ((B-A)/A) response (MD 0.02; 95% CI −0.01 to 0.04, very low certainty) or the time ratio ((D-C)/C) response (MD 0.00; 95% CI −0.06 to 0.05, very low certainty), with both tests measuring susceptibility to interference effects. Complex attention. There was little to no effect on detection task accuracy (MD 0.02; 95% CI −0.04 to 0.08), or response time (MD 0.02;95% CI 0.01 to 0.03), and little to no effect on identification task accuracy (MD 0.00; 95% CI −0.04 to 0.05) or response time (MD 0.00;95% CI −0.01 to 0.02) (low certainty evidence for all outcomes). No other cognitive domains were investigated in children.
A single study among elderly people provided very low certainty evidence that more frequent mobile phone use may have little to no effect on the odds of a decline in global cognitive function (odds ratio, OR 0.81; 95% CI 0.42 to 1.58, 649 participants) or a decline in executive function (OR 1.07; 95% CI 0.37 to 3.05, 146 participants), and may lead to a small, probably unimportant, reduction in the odds of a decline in complex attention (OR 0.67;95%CI 0.27 to 1.68, 159 participants) and a decline in learning and memory (OR 0.75; 95% CI 0.29 to 1.99, 159 participants). An exposure–response relationship was not identified for any of the cognitive outcomes.
This systematic review and meta-analysis found only a few studies that provided very low to low certainty evidence of little to no association between RF-EMF exposure and learning and memory, executive function and complex attention. None of the studies among children reported on global cognitive function or other domains of cognition. Only one study reported a lack of an effect for all domains in elderly persons but this was of very low certainty evidence. Further studies are needed to address all types of populations, exposures and cognitive outcomes, particularly studies investigating environmental and occupational exposure in adults. Future studies also need to address uncertainties in the assessment of exposure and standardise testing of specific domains of cognitive function to enable synthesis across studies and increase the certainty of the evidence.
This review was partially funded by the WHO radioprotection programme and prospectively registered on PROSPERO CRD42021257548.
Despite increasing research interest in network dynamics and cumulative advantage/disadvantage processes, little remains known about how social capital varies across the life course. While some ...researchers suggest that social capital increases with age and others argue the opposite, this study tests these contradictory assertions by analyzing multiple indicators of social capital from a nationally representative data set on working‐age U.S. respondents. The findings reveal evidence of both social capital accumulation and decline. Social resources from occupational contacts tend to increase with age, but eventually level off among older respondents. Changes in voluntary memberships follow a similar pattern. However, daily social interaction is negatively associated with age. Overall, the results suggest that social capital embedded in occupational networks tends to accumulate across the career, even in the face of a general decline in sociability. The study also uncovers gender differences in these social capital trajectories that are linked to the distinct life experiences of men and women.
A declaração dos Principais Itens para Relatar Revisões Sistemáticas e Meta-análises (PRISMA), publicada em 2009, foi desenvolvida para ajudar revisores sistemáticos a relatar de forma transparente ...por que a revisão foi feita, os métodos empregados e o que os autores encontraram. Na última década, os avanços na metodologia e terminologia de revisões sistemáticas exigiram a atualização da diretriz. A declaração PRISMA 2020 substitui a declaração de 2009 e inclui novas orientações para relato que refletem os avanços nos métodos para identificar, selecionar, avaliar e sintetizar estudos. A estrutura e apresentação dos itens foram modificadas para facilitar a implementação. Neste artigo, apresentamos a lista de checagem PRISMA 2020 de 27 itens, uma lista de checagem expandida que detalha as recomendações para relato para cada item, a lista de checagem PRISMA 2020 para resumos e os fluxogramas revisados para novas revisões e para atualização de revisões.
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