169 research outputs found

    Coupling ecological and social network models to assess “transmission” and “contagion” of an aquatic invasive species

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    Network analysis is used to address diverse ecological, social, economic, and epidemiological questions, but few efforts have been made to combine these field-specific analyses into interdisciplinary approaches that effectively address how complex systems are interdependent and connected to one another. Identifying and understanding these cross-boundary connections improves natural resource management and promotes proactive, rather than reactive, decisions. This research had two main objectives; first, adapt the framework and approach of infectious disease network modeling so that it may be applied to the socio-ecological problem of spreading aquatic invasive species, and second, use this new coupled model to simulate the spread of the invasive Chinese mystery snail (Bellamya chinensis) in a reservoir network in Southeastern Nebraska, USA. The coupled model integrates an existing social network model of how anglers move on the landscape with new reservoir-specific ecological network models. This approach allowed us to identify 1) how angler movement among reservoirs aids in the spread of B. chinensis, 2) how B. chinensis alters energy flows within individual-reservoir food webs, and 3) a new method for assessing the spread of any number of non-native or invasive species within complex, social-ecological systems

    The Elephant Queen: Can a nature documentary help to increase tolerance towards elephants?

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    Conflict between humans and elephants is one of the more complex examples of human‐wildlife conflict, a key challenge for wildlife conservation. While interventions exist to separate humans from elephants, few exist aimed at bringing the two species closer together. This study assesses if a natural history film, The Elephant Queen (TEQ), makes communities living around elephants more tolerant of conflict with elephants. Questionnaires and interviews were conducted before and after seeing the film screened on a mobile cinema in Southern Kenya. A double robust ordinal regression analysis using 357 matching specifications to measure the effect size of viewing TEQ on the six criteria identified as being drivers of tolerance of a wild animal by the Hazard Acceptance model. This study found that students aged between 16 and 18 gained knowledge (mean effect size = 0.27) and affection (mean effect size = 0.17) towards elephants and felt the benefits of elephants more keenly (mean effect size = 0.26) following viewing TEQ. Community members aged between 16–80 also gained knowledge (mean effect size = 0.21) and saw the benefits of elephants (mean effect size = 0.15) but felt the costs of living with elephants more profoundly after viewing TEQ (mean effect size = −0.11). After 90 days a follow‐up survey also showed a significant increase in community “affection” towards elephants (mean effect size = 0.11), however the costs, benefits and knowledge gained had been reduced to a statistically insignificant level compared to baseline. Our results suggest that natural history films can serve as a valuable tool in inspiring young minds. When shown to an adult audience, changes were more nuanced and some of the changes were short lived (<3 months). Read the free Plain Language Summary for this article on the Journal blog

    Terrestrial habitat requirements of nesting freshwater turtles

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    Because particular life history traits affect species vulnerability to development pressures, cross-species summaries of life history traits are useful for generating management guidelines. Conservation of aquatic turtles, many members of which are regionally or globally imperiled, requires knowing the extent of upland habitat used for nesting. Therefore, we compiled distances that nests and gravid females had been observed from wetlands. Based on records of \u3e 8000 nests and gravid female records compiled for 31 species in the United States and Canada, the distances that encompass 95% of nests vary dramatically among genera and populations, from just 8 m for Malaclemys to nearly 1400 m for Trachemys. Widths of core areas to encompass varying fractions of nesting populations (based on mean maxima across all genera) were estimated as: 50% coverage = 93 m, 75% = 154 m, 90% = 198 m, 95% = 232 m, 100% = 942 m. Approximately 6–98 m is required to encompass each consecutive 10% segment of a nesting population up to 90% coverage; thereafter, ca. 424 m is required to encompass the remaining 10%. Many genera require modest terrestrial areas (\u3c200 m zones) for 95% nest coverage (Actinemys, Apalone, Chelydra, Chrysemys, Clemmys, Glyptemys, Graptemys, Macrochelys, Malaclemys, Pseudemys, Sternotherus), whereas other genera require larger zones (Deirochelys, Emydoidea, Kinosternon, Trachemys). Our results represent planning targets for conserving sufficient areas of uplands around wetlands to ensure protection of turtle nesting sites, migrating adult female turtles, and dispersing turtle hatchlings

    Measurement of the W+W- Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Dilepton Events

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    We present a measurement of the W+W- production cross section using 184/pb of ppbar collisions at a center-of-mass energy of 1.96 TeV collected with the Collider Detector at Fermilab. Using the dilepton decay channel W+W- -> l+l-vvbar, where the charged leptons can be either electrons or muons, we find 17 candidate events compared to an expected background of 5.0+2.2-0.8 events. The resulting W+W- production cross section measurement of sigma(ppbar -> W+W-) = 14.6 +5.8 -5.1 (stat) +1.8 -3.0 (syst) +-0.9 (lum) pb agrees well with the Standard Model expectation.Comment: 8 pages, 2 figures, 2 tables. To be submitted to Physical Review Letter

    Timing of Radiotherapy (RT) after Radical Prostatectomy (RP): Long-term outcomes in the RADICALS-RT trial [NCT00541047]

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    Background The optimal timing of radiotherapy (RT) after radical prostatectomy for prostate cancer has been uncertain. RADICALS-RT compared efficacy and safety of adjuvant RT versus an observation policy with salvage RT for PSA failure. Methods RADICALS-RT was a randomised controlled trial enrolling patients with ≥1 risk factor (pT3/4, Gleason 7-10, positive margins, pre-op PSA≥10ng/ml) for recurrence after radical prostatectomy. Patients were randomised 1:1 to adjuvant RT (“Adjuvant-RT”) or an observation policy with salvage RT for PSA failure (“Salvage-RT”) defined as PSA≥0.1ng/ml or 3 consecutive rises. Stratification factors were Gleason score, margin status, planned RT schedule (52.5Gy/20 fractions or 66Gy/33 fractions) and treatment centre. The primary outcome measure was freedom-from-distant metastasis, designed with 80% power to detect an improvement from 90% with Salvage-RT (control) to 95% at 10yr with Adjuvant-RT. Secondary outcome measures were bPFS, freedom-from-non-protocol hormone therapy, safety and patient-reported outcomes. Standard survival analysis methods were used; HR<1 favours Adjuvant-RT. Findings Between Oct-2007 and Dec-2016, 1396 participants from UK, Denmark, Canada and Ireland were randomised: 699 Salvage-RT, 697 Adjuvant-RT. Allocated groups were balanced with median age 65yr. 93% (649/697) Adjuvant-RT reported RT within 6m after randomisation; 39% (270/699) Salvage-RT reported RT during follow-up. Median follow-up was 7.8 years. With 80 distant metastasis events, 10yr FFDM was 93% for Adjuvant-RT and 90% for Salvage-RT: HR=0.68 (95%CI 0·43–1·07, p=0·095). Of 109 deaths, 17 were due to prostate cancer. Overall survival was not improved (HR=0.980, 95%CI 0.667–1.440, p=0.917). Adjuvant-RT reported worse urinary and faecal incontinence one year after randomisation (p=0.001); faecal incontinence remained significant after ten years (p=0.017). Interpretation Long-term results from RADICALS-RT confirm adjuvant RT after radical prostatectomy increases the risk of urinary and bowel morbidity, but does not meaningfully improve disease control. An observation policy with salvage RT for PSA failure should be the current standard after radical prostatectomy

    Proceedings of the 2016 Childhood Arthritis and Rheumatology Research Alliance (CARRA) Scientific Meeting

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    Probabilistic analysis of blast-obstacle interaction in a crowded internal environment

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    Recent terror events such as the Manchester Arena bombing and Brussels and Istanbul airport attacks featured improvised explosive devices detonated in crowded internal spaces. A blast wave that propagates in the presence of obstacles will have fundamentally different properties to those of an unimpeded blast wave. Physical processes such as reflection, diffraction, and superposition of multiple wave fronts result in highly complex and situational-dependent loading characteristics which cannot be predicted using simple tools such as those for predicting free-field blast parameters. The influence of blast-obstacle interaction within an internal environment has not yet been studied. This article uses computational fluid dynamics within a probabilistic framework to quantify the influence of obstacle density and positioning on blast loading characteristics. Two mechanisms which alter the properties of a blast wave are studied: ‘channelling’ and ‘shielding’. It is shown that channelling effects are highly localised and result in increased loading near the explosive, the effect of which increases with obstacle density. Shielding is shown to be a cumulative effect which increases with distance from the explosive, and with increasing obstacle density. Whole-domain cumulative density functions are used to derive quantitative descriptors of the loading characteristics and how they vary relative to simple benchmark cases, with a view to providing clear guidance on the development of future predictive tools

    Distribution and Habitat Associations of Juvenile Common Snook in the Lower Rio Grande, Texas

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    Common Snook Centropomus undecimalis were once abundant off the Texas coast, but these populations are now characterized by low abundance and erratic recruitment. Most research concerning Common Snook in North America has been conducted in Florida and very little is known about the specific biology and habitat needs of Common Snook in Texas. The primary objective of this study was to describe the habitat use patterns of juvenile Common Snook and their role in the fish assemblage in the lower portion of the Rio Grande, Texas. Secondarily, we documented the relationship between age and juvenile reproductive development. Fish were collected during January–March 2006 from the lower 51.5 km of the Rio Grande using a bottom trawl and boat-mounted electrofisher. Measurements of water quality and other habitat traits were recorded at each sampling site. We captured 225 Common Snook exclusively in freshwater habitats above river kilometer 12.9. The distribution of juvenile Common Snook was not random, but influenced primarily by turbidity and dissolved oxygen. Sex differentiation and gonadal development based on histological examination of gonads established that age-1 and age-2 Common Snook were juvenile, prepubertal males. There was no difference between the age groups in their overall distribution in the river. However, age-2 Common Snook were associated with deeper areas with faster currents, higher conductivity, and steeper banks. Overall, Common Snook in the lower Rio Grande show substantial differences in habitat use than their counterparts in other parts of the range of the species, but it is unclear whether this is due to differences in habitat availability, behavioral plasticity, or some combination thereof
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