237 research outputs found
Emerging technologies in physics education
Three emerging technologies in physics education are evaluated from the
interdisciplinary perspective of cognitive science and physics education
research. The technologies - Physlet Physics, the Andes Intelligent Tutoring
System (ITS), and Microcomputer-Based Laboratory (MBL) Tools - are assessed
particularly in terms of their potential at promoting conceptual change,
developing expert-like problem-solving skills, and achieving the goals of the
traditional physics laboratory. Pedagogical methods to maximize the potential
of each educational technology are suggested.Comment: Accepted for publication in the Journal of Science Education and
Technology; 20 page
The neural basis of perceived intensity in natural and artificial touch
Electrical stimulation of sensory nerves is a powerful tool for studying neural coding because it can activate neural populations in ways that natural stimulation cannot. Electrical stimulation of the nerve has also been used to restore sensation to patients who have suffered the loss of a limb. We have used long-term implanted electrical interfaces to elucidate the neural basis of perceived intensity in the sense of touch. To this end, we assessed the sensory correlates of neural firing rate and neuronal population recruitment independently by varying two parameters of nerve stimulation: pulse frequency and pulse width. Specifically, two amputees, chronically implanted with peripheral nerve electrodes, performed each of three psychophysical tasks-intensity discrimination, magnitude scaling, and intensity matching-in response to electrical stimulation of their somatosensory nerves. We found that stimulation pulse width and pulse frequency had systematic, cooperative effects on perceived tactile intensity and that the artificial tactile sensations could be reliably matched to skin indentations on the intact limb. We identified a quantity we termed the activation charge rate (ACR), derived from stimulation parameters, that predicted the magnitude of artificial tactile percepts across all testing conditions. On the basis of principles of nerve fiber recruitment, the ACR represents the total population spike count in the activated neural population. Our findings support the hypothesis that population spike count drives the magnitude of tactile percepts and indicate that sensory magnitude can be manipulated systematically by varying a single stimulation quantity
A core outcome set for trials in miscarriage management and prevention: An international consensus development study
Objective: To develop core outcome sets (COS) for miscarriage management and prevention. Design: Modified Delphi survey combined with a consensus development meeting. Setting: International. Population: Stakeholder groups included healthcare providers, international experts, researchers, charities and couples with lived experience of miscarriage from 15 countries: 129 stakeholders for miscarriage management and 437 for miscarriage prevention. Methods: Modified Delphi method and modified nominal group technique. Results: The final COS for miscarriage management comprises six outcomes: efficacy of treatment, heavy vaginal bleeding, pelvic infection, maternal death, treatment or procedure-related complications, and patient satisfaction. The final COS for miscarriage prevention comprises 12 outcomes: pregnancy loss <24 weeks’ gestation, live birth, gestation at birth, pre-term birth, congenital abnormalities, fetal growth restriction, maternal (antenatal) complications, compliance with intervention, patient satisfaction, maternal hospitalisation, neonatal or infant hospitalisation, and neonatal or infant death. Other outcomes identified as important were mental health-related outcomes, future fertility and health economic outcomes. Conclusions: This study has developed two core outcome sets, through robust methodology, that should be implemented across future randomised trials and systematic reviews in miscarriage management and prevention. This work will help to standardise outcome selection, collection and reporting, and improve the quality and safety of future studies in miscarriage
A core outcome set for trials in miscarriage management and prevention: an international consensus development study.
OBJECTIVE: To develop core outcome sets (COS) for miscarriage management and prevention. DESIGN: Modified Delphi survey combined with a consensus development meeting. SETTING: International. POPULATION: Stakeholder groups included healthcare providers, international experts, researchers, charities and couples with lived experience of miscarriage from 15 countries: 129 stakeholders for miscarriage management and 437 for miscarriage prevention. METHODS: Modified Delphi method and modified nominal group technique. RESULTS: The final COS for miscarriage management comprises six outcomes: efficacy of treatment, heavy vaginal bleeding, pelvic infection, maternal death, treatment or procedure-related complications, and patient satisfaction. The final COS for miscarriage prevention comprises 12 outcomes: pregnancy loss <24 weeks' gestation, live birth, gestation at birth, pre-term birth, congenital abnormalities, fetal growth restriction, maternal (antenatal) complications, compliance with intervention, patient satisfaction, maternal hospitalisation, neonatal or infant hospitalisation, and neonatal or infant death. Other outcomes identified as important were mental health-related outcomes, future fertility and health economic outcomes. CONCLUSIONS: This study has developed two core outcome sets, through robust methodology, that should be implemented across future randomised trials and systematic reviews in miscarriage management and prevention. This work will help to standardise outcome selection, collection and reporting, and improve the quality and safety of future studies in miscarriage
Automating the Communication of Cybersecurity Knowledge: Multi-Case Study
Cybersecurity is essential for the protection of companies against cyber
threats. Traditionally, cybersecurity experts assess and improve a company's
capabilities. However, many small and medium-sized businesses (SMBs) consider
such services not to be affordable. We explore an alternative do-it-yourself
(DIY) approach to bringing cybersecurity to SMBs. Our method and tool, CYSEC,
implements the Self-Determination Theory (SDT) to guide and motivate SMBs to
adopt good cybersecurity practices. CYSEC uses assessment questions and
recommendations to communicate cybersecurity knowledge to the end-user SMBs and
encourage self-motivated change. In this paper, the operationalisation of SDT
in CYSEC is presented and the results of a multi-case study shown that offer
insight into how SMBs adopted cybersecurity practices with CYSEC. Effective
automated cybersecurity communication depended on the SMB's hands-on skills,
tools adaptedness, and the users' willingness to documenting confidential
information. The SMBs wanted to learn in simple, incremental steps, allowing
them to understand what they do. An SMB's motivation to improve security
depended on the fitness of assessment questions and recommendations with the
SMB's business model and IT infrastructure. The results of this study indicate
that automated counselling can help many SMBs in security adoption. The final
publication is available at Springer via
https://link.springer.com/chapter/10.1007%2F978-3-030-59291-2_8Comment: 14 pages, 1 figure, 13th World Conference on Information Security
Educatio
Environmental Factors in the Relapse and Recurrence of Inflammatory Bowel Disease:A Review of the Literature
The causes of relapse in patients with Crohn's disease (CD) and ulcerative colitis (UC) are largely unknown. This paper reviews the epidemiological and clinical data on how medications (non-steroidal anti-inflammatory drugs, estrogens and antibiotics), lifestyle factors (smoking, psychological stress, diet and air pollution) may precipitate clinical relapses and recurrence. Potential biological mechanisms include: increasing thrombotic tendency, imbalances in prostaglandin synthesis, alterations in the composition of gut microbiota, and mucosal damage causing increased permeability
Contribution of HOGG1 Ser326Cys Polymorphism to the Development of Prostate Cancer in Smokers: Meta-Analysis of 2779 Cases and 3484 Controls
The HOGG1 gene catalyzes the excision of modified bases and removal of DNA damage adducts. It may play an important role in the prevention of carcinogenesis. Ser326Cys polymorphism localizes in exon 7 of the hOGG1 gene. It takes the form of an amino acid substitution, from serine to cysteine, in codon 326. Several epidemiological association studies have been conducted on this polymorphism and its relationship with the risk of prostate cancer. However, results have been conflicting. To resolve this conflict, we conducted a meta-analysis on the association between this polymorphism and prostate cancer, taking into account race, country, sources of controls, and smoking status. A total of nine studies covering 2779 cases and 3484 controls were included in the current meta-analysis. Although no significant association was found between hOGG1 Ser326Cys polymorphism and prostate cancer susceptibility in the pooled analysis, individuals with Ser/Cys+Cys/Cys genotypes were found to have greater risk of prostate cancer if they were also smokers (OR = 2.66, 95% CI = 1.58−4.47) rather than non-smokers (OR = 2.18, 95% CI = 1.13−4.19), compared with those with Ser/Ser genotype. In conclusion, our meta-analysis demonstrates that hOGG1 Ser326Cys polymorphism is a risk factor for prostate cancer in smokers. Further studies are needed to confirm this relationship
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015
SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation
Magnetically gated accretion in an accreting ‘non-magnetic’ white dwarf
White dwarfs are often found in binary systems with orbital periods ranging from tens of minutes to hours in which they can accrete gas from their companion stars. In about 15 per cent of these binaries, the magnetic field of the white dwarf is strong enough (at 106 gauss or more) to channel the accreted matter along field lines onto the magnetic poles1,2. The remaining systems are referred to as ‘non-magnetic’, because until now there has been no evidence that they have a magnetic field that is strong enough to affect the accretion dynamics. Here we report an analysis of archival optical observations of the ‘non-magnetic’ accreting white dwarf in the binary system MV Lyrae, whose light curve displays quasi-periodic bursts of about 30 minutes duration roughly every 2 hours. The timescale and amplitude of these bursts indicate the presence of an unstable, magnetically regulated accretion mode, which in turn implies the existence of magnetically gated accretion3,4,5, in which disk material builds up around the magnetospheric boundary (at the co-rotation radius) and then accretes onto the white dwarf, producing bursts powered by the release of gravitational potential energy. We infer a surface magnetic field strength for the white dwarf in MV Lyrae of between 2 × 104 gauss and 1 × 105 gauss, too low to be detectable by other current methods. Our discovery provides a new way of studying the strength and evolution of magnetic fields in accreting white dwarfs and extends the connections between accretion onto white dwarfs, young stellar objects and neutron stars, for which similar magnetically gated accretion cycles have been identified6,7,8,9
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