144 research outputs found

    Medical Implications of Space Radiation Exposure Due to Low Altitude Polar Orbits

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    Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and Solar Particle Events may pose a critical health risk to future spaceflight crews and can have a serious impact to all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960's Manned Orbiting Laboratory program's space vehicle and the high inclination polar orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity. In this study, we have modeled the nominal and off-nominal radiation environment that a MOL-like spacecraft vehicle would be exposed to during a 30-day mission using high performance, multi-core computers. Projected doses from a historically large SPE (e.g. the August 1972 solar event) have been analyzed in the context of the MOL orbit profile, providing an opportunity to study its impact to crew health and subsequent contingencies.It is reasonable to presume that future commercial, government, and military spaceflight missions in low-Earth orbit will have vehicles with similar shielding and orbital profiles. Studying the impact of cosmic radiation to the mission's operational integrity and the health of MOL crewmembers provides an excellent surrogate and case-study for future commercial and military spaceflight missions.Comment: 6 pages, 4 figures, 2 table

    Missing Persons: a Need for Initial Call Policy and Procedure

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    The need for Initial Response procedures in missing persons cases are discussed

    Fact sheet: Post-wildfire fuels and regeneration dynamics

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    Western forests are increasingly subject to large, severe wildfires that leave behind large quantities of standing and fallen woody debris. In areas that experience total overstory tree mortality, a lack of seed sources may affect future ecosystem trajectories. ERI researchers studied 14 ponderosa pine-dominated wildfire sites of different ages throughout Arizona to better understand snag and woody debris dynamics, and to assess post-fire regeneration in terms of probable future successional trajectories

    Climate Variability and Change Impact on Crop Production: Evidence from Ghana

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    This paper explores the impact of climate variability and/or change on two major crop yields (cassava and maize) and cash crop (cocoa) in two districts in different agroecological zones - Atwima Mponua (Semi-Deciduous Forest Zone) and Ejura-Sekyeredumase (Transition Zone) of the Ashanti Region of Ghana. A comparative-case mixed-methods research design was adopted for the study, involving household survey questionnaires, focus group discussions (FGDs) and in-depth interviews with key informants to discuss farmers’ perceptions about changes in climate and impact on crop yields. Three hundred participants were involved in the study - 150 from each district. The study also used time series panel data approach to analyse the impact of climate variables (mean annual maximum and minimum temperatures; and total rainfall) on the three crops over the period 1992 - 2014.Farmers perceived changes in the weather patterns - mainly increasing temperature and erratic and low rainfall. Besides, farmers had observed invasion of weeds; and dryness of aquatic habitats (especially, during dry periods); and loss of major staples. The findings from the analysis of secondary data corroborate farmers’ perceptions about changes in climate and its negative impacts on cassava and maize yields for the past 20-30 years. However, qualitative feedback about impact of climate variables on cocoa yield conflicted with the findings of analysis of secondary data. The findings from this study can form a basis for policy makers to develop region specific adaptation policies to address climate change impacts on crops studied and extend it to other crops. Keywords: Climate variability and change; Vulnerability; Food crop; Cash crop. DOI: 10.7176/JEES/12-12-03 Publication date: December 31st 202

    Biocarbon ureterostomy device for urinary diversion Multicenter clinical trial

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    The bioCarbon ureterostomy device is a stomal prosthesis for upper tract urinary diversion that has had preliminary successes in animal and human trials in Europe and Peru. Implantation of a pure carbon stomal prosthesis offers the potential advantages of high biocompatibility, lack of encrustation, and elimination of stomal stenosis which is frequently associated with cutaneous ureterostomy. Nine bioCarbon ureterostomy devices were implanted from August, 1984 through July, 1985. Although successful implantation was achieved in 2 patients, the complication rate was high. The bioCarbon ureterostomy device has potential as an alternative form of urinary diversion. However, significant problems need to be remedied before it can be recommended for routine clinical application.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28101/1/0000548.pd

    A unifying framework for understanding ecological and evolutionary population connectivity

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    Although the concept of connectivity is ubiquitous in ecology and evolution, its definition is often inconsistent, particularly in interdisciplinary research. In an ecological context, population connectivity refers to the movement of individuals or species across a landscape. It is measured by locating organisms and tracking their occurrence across space and time. In an evolutionary context, connectivity is typically used to describe levels of current and past gene flow, calculated from the degree of genetic similarity between populations. Both connectivity definitions are useful in their specific contexts, but rarely are these two perspectives combined. Different definitions of connectivity could result in misunderstandings across subdisciplines. Here, we unite ecological and evolutionary perspectives into a single unifying framework by advocating for connectivity to be conceptualized as a generational continuum. Within this framework, connectivity can be subdivided into three timescales: (1) within a generation (e.g., movement), (2) across one parent-offspring generation (e.g., dispersal), and (3) across two or more generations (e.g., gene flow), with each timescale determining the relevant context and dictating whether the connectivity has ecological or evolutionary consequences. Applying our framework to real-world connectivity questions can help to identify sampling limitations associated with a particular methodology, further develop research questions and hypotheses, and investigate eco-evolutionary feedback interactions that span the connectivity continuum. We hope this framework will serve as a foundation for conducting and communicating research across subdisciplines, resulting in a more holistic understanding of connectivity in natural systems

    The Reputational Consequences of Failed Replications and Wrongness Admission among Scientists

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    Scientists are dedicating more attention to replication efforts. While the scientific utility of replications is unquestionable, the impact of failed replication efforts and the discussions surrounding them deserve more attention. Specifically, the debates about failed replications on social media have led to worry, in some scientists, regarding reputation. In order to gain data-informed insights into these issues, we collected data from 281 published scientists. We assessed whether scientists overestimate the negative reputational effects of a failed replication in a scenario-based study. Second, we assessed the reputational consequences of admitting wrongness (versus not) as an original scientist of an effect that has failed to replicate. Our data suggests that scientists overestimate the negative reputational impact of a hypothetical failed replication effort. We also show that admitting wrongness about a non-replicated finding is less harmful to one’s reputation than not admitting. Finally, we discovered a hint of evidence that feelings about the replication movement can be affected by whether replication efforts are aimed one’s own work versus the work of another. Given these findings, we then present potential ways forward in these discussions

    Migraine aura or transient ischemic attacks? A five-year follow-up case-control study of women with transient central nervous system disorders in pregnancy

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    <p>Abstract</p> <p>Background</p> <p>Migraine aura may be difficult to differentiate from transient ischemic attacks and other transient neurological disorders in pregnant women. The aims of the present study were to investigate and diagnose all pregnant women with transient neurological disorders of suspected central nervous system origin, and to compare this group with a control group of pregnant women with regard to vascular risk factors and prognosis.</p> <p>Methods</p> <p>During a 28 month period, 41 patients were detected with transient neurological symptoms during pregnancy. These were studied in detail with thorough clinical and laboratory investigations in order to make a certain diagnosis and to evaluate whether the episodes might be of a vascular nature. For comparison, the same investigations were performed in 41 pregnant controls. To assess the prognosis, both patients and controls were followed with questionnaires every year for five years.</p> <p>Results</p> <p>Migraine with aura was the most common cause of symptoms during pregnancy, occurring in 34 patients, while 2 were diagnosed with stroke, 2 with carpal tunnel syndrome, 1 with partial epilepsy, 1 with multiple sclerosis and 1 with presyncope. Patients had more headache before pregnancy than controls, but the average levels of vascular risk factors were similar. None of the patients or the controls reported cerebrovascular episodes during the five-year follow-up.</p> <p>Conclusion</p> <p>The diagnosis of migraine aura was difficult because for many patients it was their first ever attack and headache tended to be absent or of non-migraineous type. The aura features were more complex, with several aura symptoms and a higher prevalence of sensory and dysphasic aura than usual. Gradually developing aura symptoms, or different aura symptoms occurring in succession as described in the International Classification of Headache Disorders, seem to be useful for differentiating aura from other transient disorders. A meticulous history and clinical neurological examination are more useful than routine supplementary investigations for cerebrovascular disease. The five-year follow-up clearly indicates that migraine with aura in pregnancy usually has a good prognosis with regard to cerebrovascular events.</p
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