173 research outputs found

    Have Lesser Scaup, Aythya affinis, Reproductive Rates Declined in Parkland Manitoba?

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    Long-term surveys indicate that the scaup populations have declined over the past 20 years, and that this is probably the result of decreases in Lesser Scaup (Aythya affinis) rather than Greater Scaup (Aythya marila) numbers. To identify factors possibly related to the decline, we estimated demographic parameters for a local population of Lesser Scaup at Erickson, Manitoba, that was well studied before declines occurred and compared these estimates to historic rates. On average, nests were initiated later than in the past, and recent estimates of nesting success and duckling survival were lower than historical estimates. Breeding-season survival of adult females was estimated as 72.6%, with most (83%) mortality occurring during nesting. Current estimates of demographic rates at Erickson are too low to maintain a stable local population, and suppressed reproductive rates might be the proximate cause of the local population decline

    Occupancy Dynamics, Roost Habitat and Prey of Mexican Spotted Owls in Utah

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    Mexican spotted owls (Strix occidentalis lucida) occupy canyon habitats that have received less attention than owls in forested environments, and yet canyon environments represent a significant portion of the owl’s range. In Utah, the owls occupy narrow and steep-walled canyons that attract high levels of human use, including climbing and hiking through nest areas, and human use levels have strongly increased in the canyons, for example, permits for access to popular climbs and hikes increased over 1700% during 1998 to 2002 in Zion National Park. To examine potential effects of recreation on the owls, we studied temporal variability of detection, occupancy, local extinction, and colonization probabilities. Our study sites included several National Parks and BLM resource areas. Our primary objective was to examine effects of recreation on site occupancy dynamics. We also investigated reproductive success, roost habitat, and prey selection. The analysis of detection rate showed strong support for constant detection probability of 89% for spotted owls among 47 sites. For both single owls and owl pairs we estimated initial occupancy rate of 83% for mesic sites and 43% for relatively xeric sites. We found that recreation was not associated with occupancy, detection, nor extinction and recolonization probabilities. Although reproductive rates varied by year, recreation was not negatively associated with production of fledgling owls per site. We also studied prey selection and roost habitat in the canyon environments. Roosts were placed on steep-walled cliffs with greater number of perches than adjacent habitats, and roosts possessed relatively high overhead tree cover, cool daytime temperatures, and thus a suitable thermal environment in the arid canyons. Pellets collected at roosts sites, upon dissection, indicated that rodents were primary prey, but also included birds, bats, and various anthropods. Woodrats (Neotoma sp.) dominated the prey frequency and biomass

    Two components for one resistivity in LaVO3/SrTiO3 heterostructures

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    A series of 100 nm LaVO3 thin films have been synthesized on (001)-oriented SrTiO3 substrates using the pulsed laser deposition technique, and the effects of growth temperature are analyzed. Transport properties reveal a large electronic mobility and a non-linear Hall effect at low temperature. In addition, a cross-over from a semiconducting state at high-temperature to a metallic state at low-temperature is observed, with a clear enhancement of the metallic character as the growth temperature increases. Optical absorption measurements combined with the two-bands analysis of the Hall effect show that the metallicity is induced by the diffusion of oxygen vacancies in the SrTiO3 substrate. These results allow to understand that the film/substrate heterostructure behaves as an original semiconducting-metallic parallel resistor, and electronic transport properties are consistently explained.Comment: Improved version as accepted in Journ Phys: Cond Mat. Additional Optical measurements are presente

    Accelerating FIU’s science research and education towards discovery and innovation by leveraging FIU’s Science DMZ

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    Research faculty and their students are spending too much time on data management issues related to the transfer of data between networks. As the campus cyberinfrastructure increases data production, the transport capacity of the network must increase proportionally to deliver the data to the High-Performance Computing centers for analysis. This work presents the experience of a research project in implementing Science DMZ at Florida International University, which added six researchers and their laboratories to the Science Network and Science DMZ. The study applied a qualitative approach to assessing the researcher’s science workflows in order to create a Science DMZ implementation plan and followed the Energy Sciences Network implementation guide

    Harvest and Non-Harvest Mortality Relationships for Lesser Scaup Breeding in Southwestern Montana

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    Since the mid-to-late 1990s, lesser scaup (Aythya affinis) populations have remained more than 20% below the population goal set forth in the North American Waterfowl Management Plan.  Accordingly, considerable attention has been directed towards understanding what factors may be limiting their population, including the role of harvest.  Red Rock Lakes National Wildlife Refuge (RRL) in southwestern Montana is the site of a long-term study of lesser scaup ecology and demography.  Preliminary harvest estimates indicate that this population is harvested at rates similar to the continental population with juveniles experiencing an annual average harvest rate of 9.1% (95% CI = 7.7 - 10.7%) and adults an average annual harvest rate of 3.6% (95% CI = 2.2 - 6.1%).  Since 2005, ~1,300 female have been banded on the study site and an additional ~1,000 females have been nasal-marked.  In addition, ~1,400 resightings have been collected for nasal-marked hens on the study site and ~340 dead recoveries from our study population have been reported from Canada to Mexico.  With results obtained from multistrata models that utilize these multiple encounter types, I will present (1) estimates of harvest and natural mortality rates for female lesser scaup banded and nasal-marked at RRL from 2005-2016; (2) how non-harvest mortality varies in relation to harvest mortality over the same period; (3) an assessment of how these rates respond to changes in hunting regulations.  These results will be used to help inform lesser scaup harvest demography, a key structural uncertainty in current harvest models identified in the draft Scaup Conservation Action Plan

    Harvest and Non-Harvest Mortality Relationships for Lesser Scaup Breeding in Southwestern Montana

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    Since the mid-to-late 1990s, lesser scaup (Aythya affinis) populations have remained more than 20% below the population goal set forth in the North American Waterfowl Management Plan.  Accordingly, considerable attention has been directed towards understanding what factors may be limiting their population, including the role of harvest.  Red Rock Lakes National Wildlife Refuge (RRL) in southwestern Montana is the site of a long-term study of lesser scaup ecology and demography with data from which survival and harvest rates can be estimated using capture-mark-recapture statistical techniques.  The role of harvest in regulating duck population dynamics, including lesser scaup, is clouded with uncertainty.  Decades of research into the additive or compensatory nature of harvest mortality has yielded little consensus as to which of these hypotheses prevail in North American duck populations.  The most limiting factor to assessing these relationships stems from lacking estimates of population size during waterfowl hunting seasons.  We assessed the relationship between survival rates and harvest rates for lesser scaup females breeding at RRL for an 11 years, beginning in 2005.  Consistent with predictions of density dependence regulation of natural mortality rates during the non-breeding season, we found evidence suggesting adult female survival rates fluctuate in response to harvest regulations, an index of population size, and the total number of lesser scaup harvested in the Pacific and Central Flyways

    Looking for a needle in a haystack: inference about individual fitness components in a heterogeneous population

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    Studies of wild vertebrates have provided evidence of substantial differences in lifetime reproduction among individuals and the sequences of life history ‘states’ during life (breeding, nonbreeding, etc.). Such differences may reflect ‘fixed’ differences in fitness components among individuals determined before, or at the onset of reproductive life. Many retrospective life history studies have translated this idea by assuming a ‘latent’ unobserved heterogeneity resulting in a fixed hierarchy among individuals in fitness components. Alternatively, fixed differences among individuals are not necessarily needed to account for observed levels of individual heterogeneity in life histories. Individuals with identical fitness traits may stochastically experience different outcomes for breeding and survival through life that lead to a diversity of ‘state’ sequences with some individuals living longer and being more productive than others, by chance alone. The question is whether individuals differ in their underlying fitness components in ways that cannot be explained by observable ‘states’ such as age, previous breeding success, etc. Here, we compare statistical models that represent these opposing hypotheses, and mixtures of them, using data from kittiwakes. We constructed models that accounted for observed covariates, individual random effects (unobserved heterogeneity), first-order Markovian transitions between observed states, or combinations of these features. We show that individual sequences of states are better accounted for by models incorporating unobserved heterogeneity than by models including first-order Markov processes alone, or a combination of both. If we had not considered individual heterogeneity, models including Markovian transitions would have been the best performing ones. We also show that inference about age-related changes in fitness components is sensitive to incorporation of underlying individual heterogeneity in models. Our approach provides insight into the sources of individual heterogeneity in life histories, and can be applied to other data sets to examine the ubiquity of our results across the tree of life

    The effect of pre-shot routines on golf wedge shot performance

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    The objective of this study was to examine the effect of pre-performance routines among golfers of low skill and non-golfers on wedge golf shot performance. The intervention strategies involved a physical skill and cognitive-behavioral routine program, as well as a physical skills-only program. Performance was measured on a pre-intervention test, postintervention test, and following a period of time without treatment, and involved wedge shots being played from distances of 40, 50, and 60 m from a target. Participants in this study (N = 68) were assigned to either a golfer or non-golfer group. Participants in the treatment groups attended 2 practice sessions per week during the acquisition phase. A variable practice design was incorporated during the intervention phase. Non-golfers in both intervention groups improved performance following the acquisition phase and maintained these levels of performance in the retention test. Greater improvements in performance were found in the non-golfer physical skills and cognitive-behavioral routine group. The non-golfer physical skills and cognitive-behavioral routine group was the only group to realize significant improvements in performance when comparing initial test performance measures to post-intervention and retention test performance measures across all test distances. Although the golfer treatment groups had consistent improvement in performance measures following the intervention phase, these improvements did not reach statistical significance in the majority of cases

    PrevalĂȘncia de Doença Hipertensiva EspecĂ­fica da Gestação em um Hospital de Ensino de Juiz de Fora - MG / Prevalency of Gestational Hypertensive Disease in a School Hospital in Juiz de Fora - MG

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    As doenças hipertensivas gestacionais sĂŁo um grande problema de saĂșde pĂșblica devido a sua relação com a morbimortalidade materna e perinatal e por apresentar significativas taxas no Brasil. Pode-se classifica-las em: hipertensĂŁo crĂŽnica, prĂ©-eclĂąmpsia sobreposta Ă  hipertensĂŁo crĂŽnica, prĂ©-eclĂąmpsia, eclampsia e hipertensĂŁo relacionada a gravidez. ComplicaçÔes frequentes como a sĂ­ndrome HELLP, coagulação intravascular disseminada, edema agudo de pulmĂŁo, prematuridade e baixo peso ao nascer podem ser evitadas a partir do rastreio correto. Este estudo contou com uma amostra de 164 gestantes agrupadas entre aquelas com pressĂŁo arterial menor que 140/90 mmHg e aquelas com maior ou igual a 140/90 mmHg. A prevalĂȘncia de sĂ­ndrome hipertensiva da gestação foi de 23,7% no qual 12,8% dessas apresentaram prĂ©-eclĂąmpsia. Esses resultados se aproximam de estudos encontrados em outras literaturas. O trabalho teve por objetivo investigar a prevalĂȘncia de sĂ­ndromes hipertensivas gestacionais em pacientes atendidas ambulatorialmente em um hospital de ensino de Juiz de Fora-MG.
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