7,650 research outputs found
Freeze Prediction Model
Measurements of wind speed, net irradiation, and of air, soil, and dew point temperatures in an orchard at the Rock Springs Agricultural Research Center, as well as topographical and climatological data and a description of the major apple growing regions of Pennsylvania were supplied to the University of Florida for use in running the P-model, freeze prediction program. Results show that the P-model appears to have considerable applicability to conditions in Pennsylvania. Even though modifications may have to be made for use in the fruit growing regions, there are advantages for fruit growers with the model in its present form
Scenarios for optimizing potato productivity in a lunar CELSS
The use of controlled ecological life support system (CELSS) in the development and growth of large-scale bases on the Moon will reduce the expense of supplying life support materials from Earth. Such systems would use plants to produce food and oxygen, remove carbon dioxide, and recycle water and minerals. In a lunar CELSS, several factors are likely to be limiting to plant productivity, including the availability of growing area, electrical power, and lamp/ballast weight for lighting systems. Several management scenarios are outlined in this discussion for the production of potatoes based on their response to irradiance, photoperiod, and carbon dioxide concentration. Management scenarios that use 12-hr photoperiods, high carbon dioxide concentrations, and movable lamp banks to alternately irradiate halves of the growing area appear to be the most efficient in terms of growing area, electrical power, and lamp weights. However, the optimal scenario will be dependent upon the relative 'costs' of each factor
Integral points on varieties with infinite \'etale fundamental group
We study integral points on varieties with infinite \'etale fundamental
groups. More precisely, for a number field and a smooth projective
variety, we prove that for any geometrically Galois cover of degree at least , there exists an ample line bundle
on such that for a general member of the complete linear
system , is geometrically irreducible and any set of
-integral points on is finite. We apply this result to
varieties with infinite \'etale fundamental group to give new examples of
irreducible divisors on varieties for which finiteness of integral points is
provable.Comment: 9 pages; comments welcome
Surviving Tenure: The Plight of Black Faculty; A Panel Discussion
This essay, delivered during the 2006 Annual Meeting in Boston, presents four tenured professors from three different universities who discuss the unique problems faced by Black faculty at predominantly White institutions as they attempt to earn tenure and promotion. Chair Kimberly Flint-Hamilton provides the introductory remarks
Aspirin for prophylactic use in the primary prevention of cardiovascular disease and cancer : a systematic review and overview of reviews
Background: Prophylactic aspirin has been considered to be beneficial in reducing the risks of heart disease and cancer. However, potential benefits must be balanced against the possible harm from side effects, such as bleeding and gastrointestinal (GI) symptoms. It is particularly important to know the risk of side effects when aspirin is used as primary prevention - that is when used by people as yet free of, but at risk of developing, cardiovascular disease (CVD) or cancer. In this report we aim to identify and re-analyse randomised controlled trials (RCTs), systematic reviews and meta-analyses to summarise the current scientific evidence with a focus on possible harms of prophylactic aspirin in primary prevention of CVD and cancer.
Objectives: To identify RCTs, systematic reviews and meta-analyses of RCTs of the prophylactic use of aspirin in primary prevention of CVD or cancer. To undertake a quality assessment of identified systematic reviews and meta-analyses using meta-analysis to investigate study-level effects on estimates of benefits and risks of adverse events; cumulative meta-analysis; exploratory multivariable meta-regression; and to quantify relative and absolute risks and benefits.
Methods: We identified RCTs, meta-analyses and systematic reviews, and searched electronic bibliographic databases (from 2008 September 2012) including MEDLINE, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, NHS Centre for Reviews and Dissemination, and Science Citation Index. We limited searches to publications since 2008, based on timing of the most recent comprehensive systematic reviews.
Results: In total, 2572 potentially relevant papers were identified and 27 met the inclusion criteria. Benefits of aspirin ranged from 6% reduction in relative risk (RR) for all-cause mortality [RR 0.94, 95% confidence interval (CI) 0.88 to 1.00] and 10% reduction in major cardiovascular events (MCEs) (RR 0.90, 95% CI 0.85 to 0.96) to a reduction in total coronary heart disease (CHD) of 15% (RR 0.85, 95% CI 0.69 to 1.06). Reported pooled odds ratios (ORs) for total cancer mortality ranged between 0.76 (95% CI 0.66 to 0.88) and 0.93 (95% CI 0.84 to 1.03). Inclusion of the Women's Health Study changed the estimated OR to 0.82 (95% CI 0.69 to 0.97). Aspirin reduced reported colorectal cancer (CRC) incidence (OR 0.66, 95% CI 0.90 to 1.02). However, including studies in which aspirin was given every other day raised the OR to 0.91 (95% CI 0.74 to 1.11). Reported cancer benefits appeared approximately 5 years from start of treatment. Calculation of absolute effects per 100,000 patient-years of follow-up showed reductions ranging from 33 to 46 deaths (all-cause mortality), 60-84 MCEs and 47-64 incidents of CHD and a possible avoidance of 34 deaths from CRC. Reported increased RRs of adverse events from aspirin use were 37% for GI bleeding (RR 1.37, 95% CI 1.15 to 1.62), between 54% (RR 1.54, 95% CI 1.30 to 1.82) and 62% (RR 1.62, 95% CI 1.31 to 2.00) for major bleeds, and between 32% (RR 1.32, 95% CI 1.00 to 1.74) and 38% (RR 1.38, 95% CI 1.01 to 1.82) for haemorrhagic stroke. Pooled estimates of increased RR for bleeding remained stable across trials conducted over several decades. Estimates of absolute rates of harm from aspirin use, per 100,000 patient-years of follow-up, were 99-178 for non-trivial bleeds, 46-49 for major bleeds, 68-117 for GI bleeds and 8-10 for haemorrhagic stroke. Meta-analyses aimed at judging risk of bleed according to sex and in individuals with diabetes were insufficiently powered for firm conclusions to be drawn.
Limitations: Searches were date limited to 2008 because of the intense interest that this subject has generated and the cataloguing of all primary research in so many previous systematic reviews. A further limitation was our potential over-reliance on study-level systematic reviews in which the person-years of follow-up were not accurately ascertainable. However, estimates of number of events averted or incurred through aspirin use calculated from data in study-level meta-analyses did not differ substantially from estimates based on individual patient data-level meta-analyses, for which person-years of follow-up were more accurate (although based on less-than-complete assemblies of currently available primary studies).
Conclusions: We have found that there is a fine balance between benefits and risks from regular aspirin use in primary prevention of CVD. Effects on cancer prevention have a long lead time and are at present reliant on post hoc analyses. All absolute effects are relatively small compared with the burden of these diseases. Several potentially relevant ongoing trials will be completed between 2013 and 2019, which may clarify the extent of benefit of aspirin in reducing cancer incidence and mortality. Future research considerations include expanding the use of IPD meta-analysis of RCTs by pooling data from available studies and investigating the impact of different dose regimens on cardiovascular and cancer outcomes
“Raising the curtain on the equality theatre”: A study of recruitment to first healthcare job post-qualification in the UK National Health Service
Background
UK equality law and National Health Service (NHS) policy requires racial equality in job appointments and career opportunities. However, recent national workforce race equality standard (WRES) data show that nearly all NHS organisations in the UK are failing to appoint ethnically diverse candidates with equivalent training and qualifications as their white counterparts. This is problematic because workforce diversity is associated with improved patient outcomes and other benefits for staff and organisations.
Aim
To better understand the reasons behind underrepresentation of ethnically diverse candidates in first NHS healthcare jobs post-qualification and to identify any structural or systemic barriers to employment for such groups.
Methods
The study was informed by critical theory and the authors’ interdisciplinary perspectives as educators and researchers in the healthcare professions. Data collected from semi-structured face-to-face interviews with 12 nurse and physiotherapy recruiting managers from two NHS trusts in London were analysed using a healthcare workforce equity and diversity conceptual lens we developed from the literature. Using this lens, we devised questions to examine six dimensions of equity and diversity in the interview data from recruiting managers.
Results
Recruiting managers said they valued the benefits of an ethnically diverse workforce for patients and their unit/organisation. However, their adherence to organisational policies for recruitment and selection, which emphasise objectivity and standardisation, acted as constraints to recognising ethnicity as an important issue in recruitment and workforce diversity. Some recruiting managers sense that there are barriers for ethnically diverse candidates but lacked information about workforce diversity, systems for monitoring recruitment, or ways to engage with staff or candidates to talk about these issues. Without this information there was no apparent problem or reason to try alternative approaches.
Conclusion
These accounts from 12 recruiting managers give a ‘backstage’ view into the reasons behind ethnic inequalities in recruitment to first healthcare job in the UK NHS. Adherence to recruitment and selection policies, which aim to support equality through standardisation and anonymisation, appear to be limiting workforce diversity and creating barriers for ethnically diverse candidates to attain the jobs that they are trained and qualified for. The Healthcare Workforce Equity + Diversity Lens we have developed can help to ‘raise the curtain on the equality theatre’ and inform more inclusive approaches to recruitment such as contextualised recruitment or effective allyship between employers and universities
Additively Manufactured Aperture-Based Fss
Frequency selective surfaces (FSSs) are arrays of patch- or aperture-based elements with specific high frequency reflective and/or transmissive properties. The specific FSS response of a given design is dictated by the element dimensions and spacing relative to adjacent elements (collectively referred to as the unit cell), along with the substrate (and superstrate if applicable) properties. As it relates to sensing, the FSS response may be affected by environmental (e.g., temperature) or structural (e.g., strain) changes. To this end, FSS-based sensors have been considered in recent years for a myriad of sensing applications including structural health monitoring (SHM). Concurrent to this, the growth of additive manufacturing (AM) technologies has opened the door for in-situ printing of FSS-based sensors. To this end, this work studies the potential for Fused Deposition Modeling (FDM) type AM-fabricated FSS-based sensors. of particular interest is the effect of the reduced electrical conductivity (common to currently available conductive FDM filaments) on the performance and repeatability of FDM-printed sensors. Results from this work show that aperture-based FSS designs maintain a resonant response when printed with a reduced-conductivity material, whereas patch-based designs no longer provide FSS functionality. In addition, the results of a measurement study on a set of five additive manufactured FSS (AM-FSS) sensors show good agreement between the simulations and measurements and a high level of measurement repeatability. For these reasons, aperture-based FSS sensors fabricated via the FDM-AM process using a reduced conductivity filament are a viable option for aperture-based FSS fabrication and sensing applications
Aspirin in primary prevention of cardiovascular disease and cancer : a systematic review of the balance of evidence from reviews of randomized trials
Background:
Aspirin has been recommended for primary prevention of cardiovascular disease (CVD) and cancer, but overall benefits are unclear. We aimed to use novel methods to re-evaluate the balance of benefits and harms of aspirin using evidence from randomised controlled trials, systematic reviews and meta-analyses.
Methods and Findings:
Data sources included ten electronic bibliographic databases, contact with experts, and scrutiny of reference lists of included studies. Searches were undertaken in September 2012 and restricted to publications since 2008. Of 2,572 potentially relevant papers 27 met the inclusion criteria. Meta-analysis of control arms to estimate event rates, modelling of all-cause mortality and L'Abbé plots to estimate heterogeneity were undertaken. Absolute benefits and harms were low: 60-84 major CVD events and 34-36 colorectal cancer deaths per 100,000 person-years were averted, whereas 46-49 major bleeds and 68-117 gastrointestinal bleeds were incurred. Reductions in all-cause mortality were minor and uncertain (Hazard Ratio 0.96; 95% CI: 0.90-1.02 at 20 years, Relative Risk [RR] 0.94, 95% CI: 0.88-1.00 at 8 years); there was a non-significant change in total CVD (RR 0.85, 95% CI: 0.69-1.06) and change in total cancer mortality ranged from 0.76 (95% CI: 0.66-0.88) to 0.93 (95% CI: 0.84-1.03) depending on follow-up time and studies included. Risks were increased by 37% for gastrointestinal bleeds (RR 1.37, 95% CI: 1.15-1.62), 54%-66% for major bleeds (Rate Ratio from IPD analysis 1.54, 95% CI: 1.30-1.82, and RR 1.62, 95% CI: 1.31-2.00), and 32%-38% for haemorrhagic stroke (Rate Ratio from IPD analysis 1.32; 95% CI: 1.00-1.74; RR 1.38; 95% CI: 1.01-1.82).
Conclusions:
Findings indicate small absolute effects of aspirin relative to the burden of these diseases. When aspirin is used for primary prevention of CVD the absolute harms exceed the benefits. Estimates of cancer benefit rely on selective retrospective re-analysis of RCTs and more information is needed
- …