1,070 research outputs found

    The Mars ancient cratered terrain, smooth plains boundary: Implications of Viking color data for evolution of the Amenthes Region

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    The global color set compiled by the Mars Consortium was investigated. The problem of application of the martian surface color data to geologic interpretation are atmospheric contributions which increase with latitude, and the high correlation among the three color bands. In southern Amenthes the classified units show areas of possible mixing between cratered tarrain and smooth plains. It is suggested that some geologically meaningful correlation exists between surface units and the transformed color data in the Amenthes region. The knobby terrain protruding through the plains units appears to be remnants of ancient cratered terrain extending northward beneath the more youthful smooth plains

    Child sexual abuse material in child-centred institutions: situational crime prevention approaches

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    This paper focuses on the potential for child-centred institutions to use situational crime prevention (SCP) strategies to prevent or reduce child sexual abuse material (CSAM)1 offending as a distinct form of child sexual abuse (CSA). We discuss the failure of the Royal Commission into Institutional Responses to Child Sexual Abuse in Australia to address the potential for CSAM offending to occur in child-centred institutions. Our premise is that CSAM offending is markedly shaped by the situation in which it occurs, rather than by any pre-existing preparedness to offend sexually against children. In this context, SCP for CSAM offending must be considered as part of overall strategies to combat CSA in institutional settings. However, we acknowledge that effective implementation of SCP in this area is not straightforward. We consider some of the challenges in implementing SCP at an institutional level

    Variation in developmental rates is not linked to environmental unpredictability in annual killifishes

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    Comparative evidence suggests that adaptive plasticity may evolve as a response to predictable environmental variation. However, less attention has been placed on unpredictable environmental variation, which is considered to affect evolutionary trajectories by increasing phenotypic variation (or bet hedging). Here, we examine the occurrence of bet hedging in egg developmental rates in seven species of annual killifish that originate from a gradient of variation in precipitation rates, under three treatment incubation temperatures (21, 23, and 25 degrees C). In the wild, these species survive regular and seasonal habitat desiccation, as dormant eggs buried in the soil. At the onset of the rainy season, embryos must be sufficiently developed in order to hatch and complete their life cycle. We found substantial differences among species in both the mean and variation of egg development rates, as well as species-specific plastic responses to incubation temperature. Yet, there was no clear relationship between variation in egg development time and variation in precipitation rate (environmental predictability). The exact cause of these differences therefore remains enigmatic, possibly depending on differences in other natural environmental conditions in addition to precipitation predictability. Hence, if species-specific variances are adaptive, the relationship between development and variation in precipitation is complex and does not diverge in accordance with simple linear relationships

    Selection of both habitat and genes in specialized and endangered caribou

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    Genetic mechanisms determining habitat selection and specialization of individuals within species have been hypothesized, but not tested at the appropriate individual level in nature. In this work, we analyzed habitat selection for 139 GPS-collared caribou belonging to 3 declining ecotypes sampled throughout Northwestern Canada. We used Resource Selection Functions comparing resources at used and available locations. We found that the 3 caribou ecotypes differed in their use of habitat suggesting specialization. On expected grounds, we also found differences in habitat selection between summer and winter, but also, originally, among the individuals within an ecotype. We next obtained Single Nucleotide Polymorphisms (SNPs) for the same caribou individuals, we detected those associated to habitat selection, and then identified genes linked to these SNPs. These genes had functions related in other organisms to habitat and dietary specializations, and climatic adaptations. We therefore suggest that individual variation in habitat selection was based on genotypic variation in the SNPs of individual caribou, indicating that genetic forces underlie habitat and diet selection in the species. We also suggest that the associations between habitat and genes that we detected may lead to lack of resilience in the species, thus contributing to caribou endangerment. Our work emphasizes that similar mechanisms may exist for other specialized, endangered species

    Spatial and isotopic niche partitioning during winter in chinstrap and Adélie penguins from the South Shetland Islands

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    © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosphere 6 (2015): art125, doi:10.1890/ES14-00287.1.Closely related species with similar ecological requirements should exhibit segregation along spatial, temporal, or trophic niche axes to limit the degree of competitive overlap. For migratory marine organisms like seabirds, assessing such overlap during the non-breeding period is difficult because of long-distance dispersal to potentially diffuse foraging habitats. Miniaturization of geolocation devices and advances in stable isotope analysis (SIA), however, provide a robust toolset to quantitatively track the movements and foraging niches of wide ranging marine animals throughout much of their annual cycle. We used light-based geolocation tags and analyzed stable carbon and nitrogen isotopes from tail feathers to simultaneously characterize winter movements, habitat utilization, and overlap of spatial and isotopic niches of migratory chinstrap (Pygoscelis antarctica) and Adélie (P. adeliae) penguins during the austral winter of 2012. Chinstrap penguins exhibited a higher diversity of movements and occupied portions of the Southern Ocean from 138° W to 30° W within a narrow latitudinal band centered on 60° S. In contrast, all tracked Adélie penguins exhibited smaller-scale movements into the Weddell Sea and then generally along a counter-clockwise path as winter advanced. Inter-specific overlap during the non-breeding season was low except during the months immediately adjacent to the summer breeding season. Intra-specific overlap by chinstraps from adjacent breeding colonies was higher throughout the winter. Spatial segregation appears to be the primary mechanism to maintain inter- and intra-specific niche separation during the non-breeding season for chinstrap and Adélie penguins. Despite low spatial overlap, however, the data do suggest that a narrow pelagic corridor in the southern Scotia Sea hosted both chinstrap and Adélie penguins for most months of the year. Shared occupancy and similar isotopic signatures of the penguins in that region suggests that the potential for inter-specific competition persists during the winter months. Finally, we note that SIA was able to discriminate eastward versus westward migrations in penguins, suggesting that SIA of tail feathers may provide useful information on population-level distribution patterns for future studies.Funds for the GLS tags were provided by the National Marine Sanctuary Foundation. Additional support for this project was provided by a Woods Hole Oceanographic Devonshire Scholarship as well as funding from the Ocean Life Institute and SeaWorld Bush Gardens Conservation Fund to MJP

    Genetic aberrations of c-myc and CCND1 in the development of invasive bladder cancer

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    Detrusor muscle invasive transitional cell carcinoma is associated with poor prognosis and is responsible for the majority of bladder cancer related deaths. Amplifications of c-myc and CCND1 are associated with detrusor-muscle-invasive transitional cell carcinoma, however, their precise role in driving disease progression is unclear. Fluorescence in situ hybridisation on archival tissue from 16 patients with primary diagnosis of ⩾pT2 transitional cell carcinoma and 15 cases with primary pTa/pT1 disease subsequently progressing to detrusor-muscle-invasion was performed, in the latter group both pre and post muscle invasive events were studied. No patients presenting with ⩾pT2 had amplification of c-myc, two out of 16 (12.5%) had CCND1 amplification. Of patients who developed ⩾pT2, two out of 15 (13.3%) had amplification of c-myc, both in ⩾pT2, five out of 15 (33.3%) had CCND1 amplification, two in pTa/pT1 tumours, three in ⩾pT2 transitional cell carcinomas. In total, two out of 31 (6.5%) of patients' ⩾pT2 TCCs were amplified for c-myc and six out of 31 (19%) were amplified for CCND1. Eighty-seven per cent (40 out of 46) of tumours were polysomic for chromosome 8 and 80% (37 out of 46) were polysomic for chromosome 11 and this reflected the high copy numbers of c-myc and CCND1 observed. In almost all cases an increase in c-myc/CCND1 copy number occurred prior to invasion and persisted in advanced disease. Amplification of CCND1 or alterations in c-myc/CCND1 early in bladder cancer may have clinical relevance in promoting and predicting progression to detrusor-muscle-invasive transitional cell carcinoma

    Genomic legacy of migration in endangered caribou

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    Wide-ranging animals, including migratory species, are significantly threatened by the effects of habitat fragmentation and habitat loss. In the case of terrestrial mammals, this results in nearly a quarter of species being at risk of extinction. Caribou are one such example of a wide-ranging, migratory, terrestrial, and endangered mammal. In populations of caribou, the proportion of individuals considered as “migrants” can vary dramatically. There is therefore a possibility that, under the condition that migratory behavior is genetically determined, those individuals or populations that are migratory will be further impacted by humans, and this impact could result in the permanent loss of the migratory trait in some populations. However, genetic determination of migration has not previously been studied in an endangered terrestrial mammal. We examined migratory behavior of 139 GPS-collared endangered caribou in western North America and carried out genomic scans for the same individuals. Here we determine a genetic subdivision of caribou into a Northern and a Southern genetic cluster. We also detect >50 SNPs associated with migratory behavior, which are in genes with hypothesized roles in determining migration in other organisms. Furthermore, we determine that propensity to migrate depends upon the proportion of ancestry in individual caribou, and thus on the evolutionary history of its migratory and sedentary subspecies. If, as we report, migratory behavior is influenced by genes, caribou could be further impacted by the loss of the migratory trait in some isolated populations already at low numbers. Our results indicating an ancestral genetic component also suggest that the migratory trait and their associated genetic mutations could not be easily re-established when lost in a population
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