491 research outputs found

    Influence of resource pulses and perennial neighbors on the establishment of an invasive annual grass in the Mojave Desert

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    Invasion by exotic annual grasses is one of the most significant threats to arid ecosystems in the western USA. Current theories of invasibility predict plant communities become more susceptible to invasion whenever there is an increase in the amount of unused resources. The objective of this field study was to examine how resource pulses and temporal variation in resource demand by the native shrub vegetation influences establishment of the invasive annual grass Schismus arabicus. Water and nitrogen were applied as pulses in early spring, mid-spring, or continuously throughout the growing season to plots containing either Atriplex confertifolia or Atriplex parryi shrubs. The effect of resource pulses on Schismus density and biomass was highly dependent on the seasonal timing of the resource pulses and the identity of the neighbor shrub. When resource pulses coincided with high rates of resource capture and growth of the native vegetation, density and biomass of Schismus was reduced. Schismusestablishment was greater under continuous resource supply compared to pulsed resource supply, likely because more soil resources were available at a shallow depth when resources were supplied at a continuous low rate. These results suggest that the establishment of invasive annual grasses in arid systems can be influenced by the magnitude and spatial distribution of resource pulses in addition to the seasonal timing of resource pulses

    Older and Younger Driver Performance at Complex Intersections: Implications for Using Perception-Response Time and Driving Simulation

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    Older drivers are at increased accident risk at intersections for a variety of maneuvers. To examine why, a study was conducted to assess older driver performance at complex intersections in a driving simulator. The University of Calgary Driving Simulator was used to test healthy older drivers (65-83, M = 71.4) and younger drivers (19-22, M = 20.7). Critical scenarios included the sudden appearance of a pedestrian in an intersection, a lastsecond yellow light, an unexpected change during a left, and a vehicle violating a stoplight. Older drivers had significantly higher perception response times (PRT) than younger drivers for the latter three of the four intersection scenarios. Analysis of specific maneuvers also revealed qualitative response differences between young and old groups. In contradiction to expectation, more older drivers ran the yellow light than younger drivers. The capability of older drivers to respond under time constraints is implicated. The utility of driving simulators to assess older driver performance at intersections was limited by the prevalence of simulator sickness

    Older and Younger Driver Performance at Complex Intersections: Implications for Using Perception-Response Time and Driving Simulation

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    Older drivers are at increased accident risk at intersections for a variety of maneuvers. To examine why, a study was conducted to assess older driver performance at complex intersections in a driving simulator. The University of Calgary Driving Simulator was used to test healthy older drivers (65-83, M = 71.4) and younger drivers (19-22, M = 20.7). Critical scenarios included the sudden appearance of a pedestrian in an intersection, a lastsecond yellow light, an unexpected change during a left, and a vehicle violating a stoplight. Older drivers had significantly higher perception response times (PRT) than younger drivers for the latter three of the four intersection scenarios. Analysis of specific maneuvers also revealed qualitative response differences between young and old groups. In contradiction to expectation, more older drivers ran the yellow light than younger drivers. The capability of older drivers to respond under time constraints is implicated. The utility of driving simulators to assess older driver performance at intersections was limited by the prevalence of simulator sickness

    Do In-Vehicle Advance Signs Benefit Older and Younger Driver Intersection Performance?

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    An experimental study was conducted to determine if intersection behavior of those 18 to 24 and 65+ benefited from advanced in-vehicle signs presented in a head-up display (HUD) format. The University of Calgary Driving Simulator (UCDS) was used to determine whether intersection performance improved in the presence of several advanced signs or whether unwanted adaptive behaviors occurred (e.g., increasing speed to run the light instead of stopping). Invehicle signs facilitated an increase in stopping occurrences for both younger and older drivers at intersections with relatively short yellow onsets. In addition, eye movement analysis revealed significant age effects with regard to vertical and horizontal gaze variablity, with younger drivers showing increases in vertical gaze variability compared to the older drivers. Younger drivers also looked more often and had longer percentage of durations fixating on the HUD compared to the older drivers

    Depression, anxiety, pain and quality of life in people living with chronic hepatitis C: A systematic review and meta-analysis

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    Objectives: Individuals infected with hepatitis C virus (HCV) can develop extrahepatic conditions which may have a significant impact on life expectancy and quality of life. We conducted a systematic review to assess the causal relationship between HCV and extrahepatic conditions and the impact of HCV upon health-related quality of life of people in the UK. / Methods: HCV advocacy groups identified conditions that they thought most important to research, and the perspectives of various stakeholders informed the scope of the review. A comprehensive literature search of a range of electronic databases and websites was undertaken. Screening, quality assessment and data extraction were conducted using specialist software. The key criterion for inclusion in a synthesis was a study’s testing of the association between HCV and either quality of life or conditions specified as important by advocacy groups: depression, anxiety or painful conditions. Other criteria relating to study populations, measures and matching of study groups were also applied. Two reviewers assessed included studies, with disagreements resolved by a third reviewer where necessary. Studies were assessed for methodological quality using standardised appraisal tools. Metaanalyses were performed. Based on the consistency and sufficiency of research evidence, the findings were graded as strong, promising, tentative or inconclusive. / Results: 71 studies were included in the review’s syntheses. All studies were judged to be at a moderate or high risk of bias. Only two UK studies met our inclusion criteria. / Quality of life: Evidence from 22 studies indicates that people with HCV have worse quality of life than ‘general’ or ‘healthy’ populations; meta-analysis of nine studies indicated\ud that the physical (PCS) and mental health (MCS) domains of quality of life on the Health-Related Quality of Life Scale were both statistically and clinically worse among HCV-infected people (PCS: MD 5.54, 95% CI 3.73-7.35, MCS: MD 3.81, 95% CI 1.97-5.64). Evidence from seven included studies suggests that people co-infected with HCV and HIV have worse quality of life than individuals with HIV only; metaanalysis of five studies indicated that both the physical and mental health domains of quality of life were significantly worse among people who were co-infected (PCS: MD 2.57, 95% CI 1.08-4.06, MCS: MD 1.88, 95% CI 0.06-3.69). / Depression and anxiety: Evidence from 22 studies indicates that depression and anxiety are more severe, and depression is more common among people with HCV compared to those without it. Meta-analysis of 12 studies identified the severity of depression in people with HCV to be significantly greater than in those without HCV (Mean difference 0.98, 95% CI 0.43-1.53). Meta-analysis of nine studies identified the severity of clinical anxiety to be significantly greater among people with HCV (Mean difference 0.47, 95% CI 0.09-0.86). Meta-analysis of seven studies identified participants with HCV to be approximately three times more likely to be depressed compared to those without HCV (OR 2.77, 95% CI 1.62-4.74). No statistically significant evidence that anxiety is more common among people with HCV was found. / Pain: Evidence was appraised from 26 studies on painful conditions. A meta-analysis of four studies indicates that people with HCV are 17% more likely to suffer from arthralgia than those without HCV (RR 1.17, 95% CI 1.04-1.31). A meta-analysis of five studies suggested that people with HCV are significantly more likely to suffer from fibromyalgia; key differences across the studies in terms of the health status (co-morbidities) of HCV patients and comparison groups mean it is not possible to quantify the increased risk attributable to HCV. Other studies, including those on arthritis, were not amenable to meta-analysis. / Conclusions: Evidence suggests an association between HCV infection and depression, anxiety, fibromyalgia, arthralgia and health-related quality of life. However, the evidence was graded as ‘promising’ or ‘tentative’ rather than ‘strong’. More high-quality research on the association between HCV and these conditions is needed

    Sexual health promotion and contraceptive services in local authorities: a systematic review of economic evaluations 2010-2015

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    Background Since 2013, health commissioners in England’s local authorities have been responsible for sexual health services, including contraception, HIV testing, STI testing and treatment, health education and specialist sexual health services. Effective commissioning requires information to indicate which interventions may, or may not, be cost-effective. However, current UK guidance and recent research on the cost-effectiveness of sexual health services provides patchy and fragmented evidence. This study aims systematically to review the evidence available on the cost-effectiveness of OECD-based interventions relevant to UK local authority-commissioned sexual health services. Methods Key informants, bibliographic database searches and reference lists of guidance documents and included studies were searched for potentially relevant research. Guided by key stakeholders, we sought economic evaluations of sexual health interventions within the responsibility of local authorities, and focused in the UK, on contraception and on health promotion, published between 2010 and 2015 in English. Eligible studies were full economic evaluations based in an OECD country. Studies were classified using a specifically developed tool and assessed for methodological risk of bias using one of three design-specific assessment tools. Descriptive frequencies of codes were analysed to provide a ‘map’ of research that informed stakeholder discussions to focus the subsequent synthesis. The characteristics of studies, quality ratings and cost outcomes from each included study were extracted into tables and findings summarised narratively. Studies were assessed for their relative cost-saving or cost-effectiveness according to NICE guidance. Results In total, 17,705 references were screened; of these, 29 met our inclusion criteria and were included in the synthesis. Nine studies were undertaken in the UK; the remainder were US based. Fifteen studies examined the economics of contraception and 14 evaluated health promotion. Overall, studies were of medium methodological quality. In general, economic evaluations of contraception reported cost-effectiveness or cost savings for ulipristal acetate (UPA) as emergency contraception, long-acting reversible contraceptives (LARCs) for regular, post-natal and post-abortion contraception, and targeting to high risk groups; none, however, reported costs per quality-adjusted life year (QALY) within NICE thresholds. Economic evaluations of sexual health promotion interventions indicated more mixed results. Only three interventions were found to be cost-effective according to the NICE thresholds for HIV or sexually transmitted infection (STI) outcomes: nurse-led rapid testing and tailored counselling; condom negotiations skills training for female sex workers; and a teacher-led STI prevention and skills training intervention. UK studies focused on health promotion and contraception, and supported the above findings. In general, there has been a reasonable amount of economic research into sexual health interventions since 2010, and these support current NICE sexual health guidance. Abstract Sexual health promotion and contraceptive services in local authorities: a systematic review of economic evaluations 2010-2015 vi Conclusions The broad nature of the research question posed in this systematic review resulted in the inclusion of a dataset very diverse in terms of populations, interventions, outcomes and types of economic evaluation designs. In considering the cost-effectiveness of these strategies in relation to their own commissioning climate, policy and decision makers should consider carefully the fit between their context and that of individual studies. Use of longer-term outcomes in trials used in economic evaluations would strengthen estimates of effects such as QALYs, as would the routine use of longitudinal cohort data

    Effective use of personal health records to support emergency services

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    Smart City systems capture and exchange information with the aim to improve public services. Particularly, healthcare data could help emergency services to plan resources and make life-saving decisions. However, the delivery of healthcare information to emergency bodies must be balanced against the concerns related to citizens’ privacy. Besides, emergency services face challenges in interpreting this data; the heterogeneity of sources and a large amount of information available represent a significant barrier. In this paper, we focus on a case study involving the use of personal health records to support emergency services in the context of a fire building evacuation. We propose a methodology involving a knowledge engineering approach and a common-sense knowledge base to address the problem of deriving useful information from health records and, at the same time, preserve citizens’ privacy. We perform extensive experiments involving a synthetic dataset of health records and a curated gold standard to demonstrate how our approach allows us to identify vulnerable people and interpret their particular needs while avoiding the disclosure of personal information

    Adults with Cerebral Palsy have Higher Prevalence of Fracture Compared with Adults Without Cerebral Palsy Independent of Osteoporosis and Cardiometabolic Diseases

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    Individuals with cerebral palsy (CP) have an increased risk of fracture throughout their lifespan based on an underdeveloped musculoskeletal system, excess body fat, diminished mechanical loading, and early development of noncommunicable diseases. However, the epidemiology of fracture among adults with CP is unknown. The purpose of this cross‐sectional study was to determine the prevalence of fracture among a large sample of privately insured adults with CP, as compared with adults without CP. Data were from the Optum Clinformatics Data Mart (Eden Prairie, MN, USA), a deidentified nationwide claims database of beneficiaries from a single private payer. Diagnostic codes were used to identify 18‐ to 64‐year‐old beneficiaries with and without CP and any fracture that consisted of osteoporotic pathological fracture as well as any type of fracture of the head/neck, thoracic, lumbar/pelvic, upper extremity, and lower extremity regions. The prevalence of any fracture was compared between adults with (n = 5,555) and without (n = 5.5 million) CP. Multivariable logistic regression was performed with all‐cause fracture as the outcome and CP group as the primary exposure. Adults with CP had a higher prevalence of all‐cause fracture (6.3% and 2.7%, respectively) and fracture of the head/neck, thoracic, lumbar/pelvic, upper extremity, and lower extremity regions compared with adults without CP (all p < 0.01). After adjusting for sociodemographic and socioeconomic variables, adults with CP had higher odds of all‐cause fracture compared with adults without CP (OR 2.5; 95% CI, 2.2 to 2.7). After further adjusting for cardiometabolic diseases, adults with CP had higher odds of all‐cause fracture compared with adults without CP (OR 2.2; 95% CI, 2.0 to 2.5). After further adjusting for osteoporosis, adults with CP still had higher odds of all‐cause fracture compared with adults without CP (OR 2.0; 95% CI, 1.8 to 2.2). These findings suggest that young and middle‐aged adults with CP have an elevated prevalence of all‐cause fracture compared with adults without CP, which was present even after accounting for cardiometabolic diseases and osteoporosis. © 2019 American Society for Bone and Mineral Research.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150537/1/jbmr3694_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150537/2/jbmr3694.pd

    Learning-by-doing as an approach to teaching social entrepreneurship

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    Many studies have explored the use of learning-by-doing in higher education, but few have applied this to social entrepreneurship contexts and applications: this paper addresses this gap in the literature. Our programme involved students working with different stakeholders in an interactive learning environment to generate real revenue for social enterprises. Our results show that learning-by-doing enables students to develop their entrepreneurial skills and enhance their knowledge of social businesses. The findings also show that students became more effective at working in teams and in formulating and applying appropriate business strategies for the social enterprises. Overall, the learning-by-doing approach discussed in this paper is capable of developing the entrepreneurial skills of students, but there are challenges that need to be addressed if such an approach is to be effective
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