3,369 research outputs found
Influence of the Agricultural Conservation Easement Program wetland practices on winter occupancy of Passerellidae sparrows and avian species richness
Wetlands enrolled in the Agricultural Conservation Easement Program (ACEP) are established as a means of restoring wetland ecosystems and wildlife habitat on private, agricultural land. In West Virginia, USA, ACEP wetlands have never been evaluated to determine how they function as wildlife habitat in comparison to other available wetland habitat in the state. We measured the wintering occupancy of Passerellidae species and apparent avian species richness on ACEP wetlands and a set of reference wetlands located on public land in West Virginia to evaluate if ACEP wetlands are being used similarly by avian species to other available wetland habitat in the state. Apparent avian species richness and the occupancy probability of four Passerellidae speciesāsong sparrows (Melospiza melodia), dark-eyed juncos (Junco hyemalis), swamp sparrows (Melospiza georgiana), and white-throated sparrows (Zonotrichia albicollis)ādid not differ between ACEP and reference sites. In addition to other vegetative and habitat associations for each species, dark-eyed junco occupancy was negatively correlated with wetland size while swamp sparrow occupancy and apparent avian species richness were positively associated with wetland size. These results indicate that ACEP wetlands are providing winter avian habitat as well as another source of wetland habitat in the state. Maintaining and expanding ACEP wetlands in West Virginia would continue to provide wetland systems in areas that are otherwise lacking these habitats
A comparison of wetland characteristics between Agricultural Conservation Easement Program and public lands wetlands in West Virginia, USA
In West Virginia, USA, there are 24 conservation easement program wetlands enrolled in the Agricultural Conservation Easement Program (ACEP). These wetlands are located on private agricultural land and are passively managed. Due to their location within fragmented agricultural areas, wetlands enrolled in ACEP in West Virginia have the potential to add wetland ecosystem services in areas that are lacking these features. We evaluated ACEP wetlands compared to reference wetlands on public land in West Virginia by using surrounding land cover, vegetative cover, and wetland features and stressors such as the presence or absence of erosion, upland inclusion, algal mats, and evidence of impacts from the surrounding landscape as surrogate measurements of wetland function on 13 ACEP wetlands and 10 reference wetlands. ACEP wetlands had higher percentages of tree coverage and a higher proportion of agricultural land in the areas immediately surrounding the wetland. Reference wetlands had higher percent coverage of emergent vegetation and had a higher proportion of forest in the immediate landscape. Our findings suggest that ACEP wetlands provide valuable early successional and forested wetland cover in a state that is largely forested. Because of this, it is important to maintain and even expand ACEP in West Virginia to continue providing a valuable source of early successional wetland habitat
Massively Expanded NEA Accessibility via Microwave-Sintered Aerobrakes
The availability of a wide range of natural resources among the near-Earth asteroid (NEA) population offers the opportunity to utilize these resources in the service of making access to most of the Solar System much easier than any classical approach which relies solely upon structural, heat-shield, life support and propellant materials lifted from Earth.We have concentrated our attention on the two main factors that influence the application and utility of in situ aerobrake manufacture on near-earth asteroids. The first of these is the use of microwave sintering in the fabrication of aerocapture heatshields for retrieval of asteroidal materials into Earth orbit; the second is assessment of the performance of these aerocapture devices, including making very large numbers of NEAs accessible as sources of essential materials to support space exploration and exploitation
Team strategic philosophy: requiem for the infinite game
Deliberate accountability has arrived in the medical arena, producing an age of reward for measured performance, and belief in publicizing metrics to ensure clarity, with winning defined as hitting targets, whereby staff are incentivised by arbitrary objectives. Finite game theory declares that players are known, rules are fixed, and the objective agreed, but infinite game theory asserts that players are both known and unknown, rules are changeable, and the objective is to perpetuate the game; these standards are clearly at odds and risk real world chaos in global universal medical education and clinical outcomes and functioning. Five principles are necessary to lead an infinite game: first, a fair basis, such that sacrifices for its advancement are promoted; second, a trusting blame-free team culture and environment; third, competitors viewed as worthy rivals, rather than adversaries, promoting healthy competition; fourth, existential flexibility when faced with credible evidence; and finally, transformational leadership; including infinite game theory into healthcare planning may be difficult, but the potential rewards are surely worth the existential fight
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Seed predation by insects across a tropical forest precipitation gradient
1. Preādispersal predation of seeds by insects can be an important source of plant mortality, with consequences for plant population dynamics and community diversity.
2. The intensity and hostāspecificity of natural enemies, including seed predators, is predicted to vary systematically across environmental gradients. These trends could contribute to largeāscale patterns in diversity, such as the widely observed positive relationship between plant species richness and precipitation. However, fundamental information on interā and intraspecific seed predation is lacking at the landscape scale.
3. We assessed the intensity of seed predation by insects at eight forest sites spanning a steep precipitation and plant speciesārichness gradient in Panama. We dissected freshly abscised fruits and seeds of woody plants to measure rates of predation, and assessed hostāspecificity by rearing insects from them.
4. On average, 22.6% of dissected seeds were predated across 31 host species. Speciesāspecific and siteālevel seed predation rates and the number of seed predator species reared per host were not significantly associated with annual rainfall or dry season water deficit.
5. In total, 45 seed predator morphospecies were reared from seeds of 16 plant species. Hostāspecificity was high, with 91% of seed predator morphospecies associated with just one plant species.
6. Our results support evidence that preādispersal insect seed predators are highly hostāspecific and exhibit great intraspecific, interspecific and landscapeāscale (i.e. betweenāsite) variation in seed predation intensity. Hostāspecific seed predators, particularly those causing moderate to high seed predation rates, could influence plant population dynamics and local community structure
Nocturnal pulse oximetry for the detection and prediction of acutemountain sickness: An observational study
Acute mountain sickness (AMS) is a well-studied illness defined by clinical features (e.g., headache and nausea), as assessed by the Lake Louise score (LLS). Although obvious in its severe form, early stages of AMS are poorly defined and easily confused with common travel-related conditions. Measurement of hypoxaemia, the cause of AMS, should be helpful, yet to date its utility for identifying AMS susceptibility remains unclear. This study quantified altitude-induced hypoxaemia in individuals during an ascent to 4800 m to determine the utility of nocturnal pulse oximetry measurements for prediction of AMS. Eighteen individuals (36 Ā± 16 years of age) ascended to 4800 m over 12 days. Symptomology of AMS was assessed each morning via LLS criteria, with participants categorized as either AMS-positive (LLS ā„ 3 with headache) or AMS-negative. Overnight peripheral oxygen saturations (ov-Spā¢O2SpO2) were recorded continuously (1 Hz) using portable oximeters. Derivatives of these recordings were compared between AMS-positive and -negative subjects (MannāWhitney U-test). Exploratory analyses (Pearson's) were conducted to investigate relationships between overnight parameters and AMS severity. Overnight derivatives, including ov-Spā¢O2SpO2, heart rate/ov-SpO2Spā¢O2, variance, oxygen desaturation index, hypoxic burden and total sleep time at <80%Ā SpO2Spā¢O2, all differed significantly between AMS-positive and -negative subjects (all P < 0.01), with cumulative/relative frequency plots highlighting these differences visually. Exploratory analysis revealed that ov-Spā¢O2SpO2Ā from 3850 m was correlated with peak LLS at 4800 m (r = 0.58ā0.61). The findings highlight the potential for overnight oximetry to predict AMS susceptibility during ascent to high altitude. Further investigation is required to develop, evaluate and optimize predictive models to improve AMS management and prevention
Diagnosing Crohn\u27s Disease: An economic analysis comparing wireless capsule endoscopy with traditional diagnostic procedures
The purpose of this study was to review economic considerations related to establishing a diagnosis of Crohn\u27s disease, and to compare the costs of a diagnostic algorithm incorporating wireless capsule endoscopy (WCE) with the current algorithm for diagnosing Crohn\u27s disease suspected in the small bowel. Published literature, clinical trial data on WCE in comparison to other diagnostic tools, and input from clinical experts were used as data sources for (1) identifying contributors to the costs of diagnosing Crohn\u27s disease; (2) exploring where WCE should be placed within the diagnostic algorithm for Crohn\u27s; and (3) constructing decision tree models with sensitivity analyses to explore costs (from a payor perspective) of diagnosing Crohn\u27s disease using WCE compared to other diagnostic methods. Literature review confirms that Crohn\u27s disease is a significant and growing public health concern from clinical, humanistic and economic perspectives, and results in a long-term burden for patients, their families, providers, insurers, and employers. Common diagnostic procedures include radiologic studies such as small bowel follow through (SBFT), enteroclysis, CT scans, ultrasounds, and MRIs, as well as serologic testing, and various forms of endoscopy. Diagnostic costs for Crohn\u27s disease can be considerable, especially given the cycle of repeat testing due to the low diagnostic yield of certain procedures and the inability of current diagnostic procedures to image the entire small bowel. WCE has a higher average diagnostic yield than comparative procedures due to imaging clarity and the ability to visualize the entire small bowel. Literature review found the average diagnostic yield of SBFT and colonoscopy for work-up of Crohn\u27s disease to be 53.87%, whereas WCE had a diagnostic yield of 69.59%. A simple decision tree model comparing two arms--colonoscopy and SBFT, or WCE--estimates that WCE produces a cost savings of 291dollars for each case presenting for diagnostic work-up for Crohn\u27s. Sensitivity analysis varying diagnostic yields of colonoscopy and SBFT vs. WCE demonstrates that WCE is still less costly than SBFT and colonoscopy even at their highest reported yields, as long as the diagnostic yield of WCE is 64.10% or better. Employing WCE as a first-line diagnostic procedure appears to be less costly, from a payor perspective, than current common procedures for diagnosing suspected Crohn\u27s disease in the small bowel. Although not addressed in this model, earlier diagnosis with WCE (due to higher diagnostic yield) also could lead to earlier management, improved quality of life and workplace productivity for people with Crohn\u27s disease
Molecular analyses reveal consistent food web structure with elevation in rainforest Drosophila ā parasitoid communities
The analysis of interaction networks across spatial environmental gradients is a powerful approach to investigate the responses of communities to global change. Using a combination of DNA metabarcoding and traditional molecular methods we built bipartite Drosophila-parasitoid food webs from six Australian rainforest sites across gradients spanning 850 m in elevation and 5Ā° Celsius in mean temperature. Our cost-effective hierarchical approach to network reconstruction separated the determination of host frequencies from the detection and quantification of interactions. The food webs comprised 5-9 host and 5-11 parasitoid species at each site, and showed a lower incidence of parasitism at high elevation. Despite considerable turnover in the relative abundance of host Drosophila species, and contrary to some previous results, we did not detect significant changes to fundamental metrics of network structure including nestedness and specialisation with elevation. Advances in community ecology depend on data from a combination of methodological approaches. It is therefore especially valuable to develop model study systems for sets of closely-interacting species that are diverse enough to be representative, yet still amenable to field and laboratory experiments
Human Ubc9 Contributes to Production of Fully Infectious Human Immunodeficiency Virus Type 1 Virions
Ubc9 was identified as a cellular protein that interacts with the Gag protein of Mason-Pfizer monkey virus. We show here that Ubc9 also interacts with the human immunodeficiency virus type 1 (HIV-1) Gag protein and that their interaction is important for virus replication. Gag was found to colocalize with Ubc9 predominantly at perinuclear puncta. While cells in which Ubc9 expression was suppressed with RNA interference produced normal numbers of virions, these particles were 8- to 10-fold less infectious than those produced in the presence of Ubc9. The nature of this defect was assayed for dependence on Ubc9 during viral assembly, trafficking, and Env incorporation. The Gag-mediated assembly of virus particles and protease-mediated processing of Gag and Gag-Pol were unchanged in the absence of Ubc9. However, the stability of the cell-associated Env glycoprotein was decreased and Env incorporation into released virions was altered. Interestingly, overexpression of the Ubc9 trans-dominant-negative mutant C93A, which is a defective E2-SUMO-1 conjugase, suggests that this activity may not be required for interaction with Gag, virion assembly, or infectivity. This finding demonstrates that Ubc9 plays an important role in the production of infectious HIV-1 virions
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