259 research outputs found

    Are Mountain Lions Really Eating Feral Horses?

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    In May 2018, the New York Times published an article titled, “Let Mountain Lions Eat Horses.” The article implies mountain lions (Puma concolor) either currently do or could limit feral horse (Equus caballus) populations across the Intermountain West. This claim, among others in the article, is not well documented in existing literature. As of March 1, 2018, the Bureau of Land Management estimated feral horse and burro populations in the western United States numbered almost 82,000 animals. I will briefly cover the evolution, extinction, and the reintroduction of feral horses to North America, their ecological effects, summarize existing peer-reviewed literature, and the political climate of feral horse management. Based on visits to kill sites from 10 radio marked mountain lions in the Delamar Mountain Range, a very arid mountain range, about 130 km northeast of Las Vegas, NV, a majority of mountain lions do consume feral horses. I will also share these preliminary findings

    Mothers' perceptions of overweight and obesity in their children

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    Background: Childhood obesity is a growing health concern and the literature implicates parents, particularly mothers. Aim: To develop understandings into the views of a group of mothers with an overweight or obese child, about their child's overweight or obesity. Method: A qualitative design informed by feminist insights. Eleven English speaking mothers of at least one overweight or obese child were drawn from a large urban community in metropolitan Australia to participate in this study. Results: Participants attributed their child's obesity to factors such as slow metabolism, sedentary lifestyle, familial or cultural factors, genetics, eating habits such as not drinking enough water, or not chewing food adequately. Participants were very concerned about their child's weight problems and their immediate concerns focussed on social problems associated with obesity/overweight. Conclusion: Understanding parental views about their children's overweight and obesity is a key step in forming effective liaisons between health professionals and parents

    Anthropogenic Subsidies Affect Common Raven Nesting, Space-Use, and Movement

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    Common raven (Corvus corax) number shave increased drastically throughout the Great Basin. Anthropogenic resources provide subsidies for growing raven populations with potential negative impacts on prey species including species of conservation concern such as greater sage-grouse (Centrocercus urophasianus).Our objective was to identify the effects of anthropogenic subsidies on raven nesting, space-use, and movement in sage-grouse habitat. We captured and radio-tagged 67 ravens between 2015 and 2018 and identified 70 nests during the 2018 breeding season. We found the majority of nests were built on anthropogenic structures. We also examined raven use of anthropogenic subsidies including highways, railroads, landfills, and agricultural fields. Finally, we examined movement behavior in terms of hourly step-length in relation to anthropogenic subsidies. Our results illustrate how ravens benefit from anthropogenic subsidies in sage-grouse habitat and the importance of subsidy management in controlling raven populations

    PEak: A Single Source of Truth for Hardware Design and Verification

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    Domain-specific languages for hardware can significantly enhance designer productivity, but sometimes at the cost of ease of verification. On the other hand, ISA specification languages are too static to be used during early stage design space exploration. We present PEak, an open-source hardware design and specification language, which aims to improve both design productivity and verification capability. PEak does this by providing a single source of truth for functional models, formal specifications, and RTL. PEak has been used in several academic projects, and PEak-generated RTL has been included in three fabricated hardware accelerators. In these projects, the formal capabilities of PEak were crucial for enabling both novel design space exploration techniques and automated compiler synthesis

    Factors Influencing Common Raven Occurrence and Density Across Cold-Desert Sagebrush Ecosystems of the Southwestern U.S.

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    Common ravens (Corvus corax) are a predator of eggs and chicks of numerous species including greater sage-grouse (Centrocercus urophasianus). Raven abundance and distribution is increasing within sagebrush ecosystems as a result of anthropogenic resource subsidies. Despite concerns about subsequent predation pressure on sage-grouse, broad-scale spatial information about raven populations remains lacking. We used hierarchical occupancy and distance sampling models to map raven density and distribution in response to natural and anthropogenic landscape covariates using \u3e15,000 point count surveys occurring within the Great Basin region since 2007. Anthropogenic factors contributing to greater raven occurrence included increased road density, presence of transmission lines, agricultural activity, and presence of roadside rest areas. Natural landscape characteristics included lower elevations with greener vegetation (NDVI), greater stream and habitat edge densities, and lower percentages of big sagebrush (A. tridentate spp.). Many of these same environmental factors influenced spatial variation in raven density, although the effects varied by field site. Both raven occurrence and density tended to increase in valleys with networks of agricultural fields, ranches, roads, and distribution lines. These features likely subsidize local raven populations, which then move into more remote shrubland environments with negative consequences for sage-grouse populations. We used the relationships identified in our model to make predictions of raven density and distribution across the Great Basin landscape. We show how these model outputs can be used to guide management decisions where raven distributions overlap with breeding sage-grouse concentration areas. Findings are preliminary and provided for timely best science

    The Mouse Cer1 (Cerberus related or homologue) Gene Is Not Required for Anterior Pattern Formation

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    AbstractCer1 is the mouse homologue of the Xenopus Cerberus gene whose product is able to induce development of head structures during embryonic development. The Cer1 protein is a member of the cysteine knot superfamily and is expressed in anterior regions of the mouse gastrula. A segmental pattern of expression with nascent and newly formed somites is also seen. This suggests an additional role in development of the axial skeleton, musculature, or peripheral nervous system. Xenopus animal cap assays and mouse germ-layer explant recombination experiments indicate that the mouse protein can act as a patterning molecule for anterior development in Xenopus, including induction of Otx2 expression, and suggest it may have a similar role in mouse development. However, we present here genetic data that demonstrate that Cer1 is not necessary for anterior patterning, Otx2 expression, somite formation, or even normal mouse morphogenesis

    Estimating Trends of Common Raven Populations in North America, 1966–2018

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    Over the last half century, common raven (Corvus corax; raven) populations have increased in abundance across much of North America. Ravens are generalist predators known to depredate the eggs and young of several sensitive species. Quantifying raven population increases at multiple spatial scales across North America will help wildlife resource managers identify areas where population increases present the greatest risk to species conservation. We used a hierarchical Bayesian modeling approach to analyze trends of standardized raven counts from 1966 to 2018 using Breeding Bird Survey data within each Level I and II ecoregion of the United States and Canada. We also compared raven abundance within and outside the distributions of 9 sensitive or endangered species. Although we found substantial evidence that raven populations have increased across North America, populations varied in growth rates and relative abundances among regions. We found 73% of Level I (11/15) and II (25/34) ecoregions demonstrated positive annual population growth rates ranging from 0.2–9.4%. We found higher raven abundance inside versus outside the distributions of 7 of the 9 sensitive species included in our analysis. Gunnison sage-grouse (Centrocercus minimus) had the highest discrepancy, with 293% more ravens within compared to outside of their range, followed by greater sandhill crane (Antigone canadensis tabida; 280%), and greater sage-grouse (C. urophasianus; 204%). Only 2 species, least tern (Sternula antillarum) and piping plover (Charadrius melodus), indicated lower raven abundance within relative to outside their distributions. Our findings will help wildlife resource managers identify regional trends in abundance of ravens and anticipate which sensitive species are at greatest risk from elevated raven populations. Future research directed at identifying the underlying regional drivers of these trends could help elucidate the most appropriate and responsive management actions and, thereby, guide the development of raven population management plans to mitigate impacts to sensitive species

    Common Ravens Disrupt Greater Sage-grouse Lekking Behavior in the Great Basin, USA

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    Expansion of human enterprise has contributed to increased abundance and distribution of common ravens (Corvus corax; ravens) across sagebrush (Artemisia spp.) ecosystems within western North America. Ravens are highly effective nest predators of greater sage-grouse (Centrocercus urophasianus; sage-grouse), a species of high conservation concern. Sage-grouse population trends are estimated using count survey data of males attending traditional breeding grounds, known as leks. We sought to investigate associations of ravens to sage-grouse lek sites and document interactions between the sage-grouse and ravens as well as those between sage-grouse and other animals observed around leks. First, we used extensive raven point counts and sage-grouse lek observation data collected across Nevada and California, USA, from 2009–2019 to evaluate spatial associations between sage-grouse and ravens while accounting for other environmental covariates. We found that ravens were more likely to be observed closer to lek sites, especially as leks increased in size. Second, we used a subset of the lek dataset from 2006–2019 to describe behavioral changes of male sage-grouse in the presence of ravens and other predators. Our analysis indicated that ravens are attracted to lek sites and were associated with disrupting lekking sage-grouse by causing flushes or ceasing displaying behaviors. These results suggest that adult and yearling sage-grouse perceive ravens as a reason to alter breeding activity, and ravens may adversely influence their reproduction during the lekking stage. Additionally, standardized techniques to count sage-grouse on leks for population trend analyses could be biased low if raven presence during surveys is not accounted for
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