431 research outputs found

    The Role of Habitat Heterogeneity in Structuring Mangrove Bird Assemblages

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    Mangrove habitats are under severe land use pressure throughout the world and Australia is no exception. Here we describe the heterogeneity of mangrove habitat and its relationship with mangrove bird diversity. We examined the role of mangrove habitat complexity in determining the richness of avian mangrove dependent species (MDS) and interior species, overall bird species richness and density. High species richness (overall and MDS) and density in the mangroves was associated with plant species richness, the density of the understory and food resource distribution. Furthermore, habitat heterogeneity rather than patch area per se was a more important predictor of species richness in the mangroves. These findings stress the importance of habitat diversity and quality to the diversity and density of birds in mangroves. Thus, habitat heterogeneity within mangroves is a crucial patch characteristic, independent of mangrove patch size, for maintaining diverse avian species assemblages

    Strong sexual size dimorphism in the Dark-eared Myza Myza celebensis, a Sulawesi-endemic honeyeater, with notes on its wing markings and moult

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    We present morphometric and moult data for the Sulawesi-endemic Dark-eared Myza, based on 35 individuals captured at Lore Lindu National Park, Central Sulawesi, during March–April and July 2011. Four individuals banded in March were recaptured at the study site in July, suggesting that the population is probably sedentary. Like most meliphagids, although this species is not sexually dimorphic in plumage, measurements show that males are significantly heavier and have longer wings, tail and head–bill than females. Seven of the 16 adults in March–April and five of the 19 in July were moulting their primary feathers. Assuming that primary moult follows breeding, estimated laying dates for adults in the final stages of moult suggest breeding in December and early April, the latter corroborated by the presence of brood patches on two females in late March. A brood patch on a female in July further suggests that the breeding season is protracted. All birds photographed also showed distinct buff tips to most, if not all, secondary coverts and buff fringes to median coverts, a feature that appears to have gone unnoticed in the literature

    The Role of Habitat Heterogeneity in Structuring Mangrove Bird Assemblages

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    Mangrove habitats are under severe land use pressure throughout the world and Australia is no exception. Here we describe the heterogeneity of mangrove habitat and its relationship with mangrove bird diversity. We examined the role of mangrove habitat complexity in determining the richness of avian mangrove dependent species (MDS) and interior species, overall bird species richness and density. High species richness (overall and MDS) and density in the mangroves was associated with plant species richness, the density of the understory and food resource distribution. Furthermore, habitat heterogeneity rather than patch area per se was a more important predictor of species richness in the mangroves. These findings stress the importance of habitat diversity and quality to the diversity and density of birds in mangroves. Thus, habitat heterogeneity within mangroves is a crucial patch characteristic, independent of mangrove patch size, for maintaining diverse avian species assemblages

    Loss of MDC1 in Endometrial Carcinoma Is Associated With Loss of MRN Complex and MMR Deficiency

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    AIM: To evaluate the frequency of loss of mediator of DNA damage checkpoint protein 1 (MDC1) protein expression in endometrial cancer (EC) and to determine whether loss of MDC1 is associated with certain clinicopathological parameters. MATERIALS AND METHODS: MDC1 expression was examined in 426 samples of EC. The nuclear immunoreactivity of the protein was defined as: negative, weak, moderate and strong. RESULTS: Loss of MDC1 expression (defined as negative nuclear staining) was found in 8.9% (38/426) of ECs and was significantly associated with the loss of MRE11 homolog, double-strand break repair nuclease, RAD50 double-strand break repair protein and nibrin complex components. In addition, loss of expression of MDC1 showed a significant correlation with any mismatch repair deficiency, with endometrioid histological subtype and low tumour grading. CONCLUSION: Based on these findings, we suggest that MDC1 loss frequently occurs in ECs with microsatellite instability. Due to deficient homologous recombination DNA repair, MDC1-negative ECs might show an increased sensitivity to poly(ADP-ribose) polymerase-inhibitory therapy

    Mass Movements of Warrumbungle National Park, New South Wales, Australia

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    The Warrumbungle Range is the mountainous eroded remnant of an Early Miocene shield volcanic complex located in the central west of New South Wales. A high-severity wildfire in Warrumbungle National Park in January 2013 was followed by intense rain, causing a number of debris flows. Several flows impacted on infrastructure such as roads and culverts and posed a severe risk to public safety, prompting a broader assessment of mass movement hazard within the park. High resolution LiDAR DEM revealed 542 locations with evidence of mass movement processes that pre-date the fire. The most common types of mass movement visible in the DEM are rotational slumps (353, 65%). The distribution of these indicated stratigraphic control, with 50% of slumps within 440 m of the volcanics-sandstone geologic contact, and typically occurring within unconsolidated volcanic colluvium and/or in situ deeply weathered volcanics. Debris flows are the next most common mass movement type after rotational slumps. Debris flow scour channels generally occurred on colluvial slopes in more elevated sites, within the volcanic rocks. DEM-extracted morphometric data was used to identify areas of debris flow hazard in WNP. Several large mass movements are morphometrically different, with some evidence for formation under different hydro-climatic conditions. A simple conceptual model of how mass movements contribute to the evolution of the Warrumbungle Range is proposed involving groundwater, deep weathering, slope retreat by mass failure, colluvial deposition and periodic incision by debris flows

    Resource Partitioning by Mangrove Bird Communities in North Australia

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    Mangrove bird communities in north Australia comprise relatively few passerine species compared with other arboreal habitats in the region. Mangroves are dominated by a few tree species and there are potentially few resource axes available for partitioning by terrestrial birds. Competition for limited resources is predicted to cause strong niche differentiation and a highly structured, but low diversity, bird assemblage. Using multivariate and bipartite network analyses based on 1771 foraging observations (33% of 5320 behavioral observations), we examined resource partitioning by 20 terrestrial bird species in mangroves of north Australia. The mangrove bird community largely comprised generalist insectivores that partitioned insects by size with moderate-to-high interspecific overlap in diet. Gleaning for insects was the most common foraging mode. Few species specialized on nectar. Flowers of one or more mangrove species were available in every month of the year and insect abundance was correlated with flowering peaks. Niche differentiation by birds was determined by food type and foraging mode more than by broad spatial (mangrove zones) or temporal (seasonal) segregation of the use of resources. There was little evidence of bird species saturation or species sorting, suggesting loose species packing and a lesser role than expected for species interactions and interference competition in structuring the bird assemblage in mangroves

    p53 suppresses type II endometrial carcinomas in mice and governs endometrial tumour aggressiveness in humans

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    Type II endometrial carcinomas are a highly aggressive group of tumour subtypes that are frequently associated with inactivation of the TP53 tumour suppressor gene. We show that mice with endometrium-specific deletion of Trp53 initially exhibited histological changes that are identical to known precursor lesions of type II endometrial carcinomas in humans and later developed carcinomas representing all type II subtypes. The mTORC1 signalling pathway was frequently activated in these precursor lesions and tumours, suggesting a genetic cooperation between this pathway and Trp53 deficiency in tumour initiation. Consistent with this idea, analyses of 521 human endometrial carcinomas identified frequent mTORC1 pathway activation in type I as well as type II endometrial carcinoma subtypes. mTORC1 pathway activation and p53 expression or mutation status each independently predicted poor patient survival. We suggest that molecular alterations in p53 and the mTORC1 pathway play different roles in the initiation of the different endometrial cancer subtypes, but that combined p53 inactivation and mTORC1 pathway activation are unifying pathogenic features among histologically diverse subtypes of late stage aggressive endometrial tumours

    X-Ray Microscopy of Spin Wave Focusing using a Fresnel Zone Plate

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    Magnonics, i.e. the artificial manipulation of spin waves, is a flourishing field of research with many potential uses in data processing within reach. Apart from the technological applications the possibility to directly influence and observe these types of waves is of great interest for fundamental research. Guidance and steering of spin waves has been previously shown and lateral spin wave confinement has been achieved. However, true spin wave focusing with both lateral confinement and increase in amplitude has not been shown before. Here, we show for the first time spin wave focusing by realizing a Fresnel zone plate type lens. Using x-ray microscopy we are able to directly image the propagation of spin waves into the nanometer sized focal spot. Furthermore, we observe that the focal spot can be freely moved in a large area by small variations of the bias field. Thus, this type of lens provides a steerable intense nanometer sized spin wave source. Potentially, this could be used to selectively illuminate magnonic devices like nano oscillators with a steerable spin wave beam

    Societal sentience: constructions of the public in animal research policy and practice

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    The use of non-human animals as models in research and drug testing is a key route through which contemporary scientific knowledge is certified. Given ethical concerns, regulation of animal research promotes the use of less ‘sentient’ animals. This paper draws on a documentary analysis of legal documents, and qualitative interviews with Named Veterinary Surgeons and others at a commercial laboratory in the UK. Its key claim is that the concept of animal sentience is entangled with a particular imaginary of how the general public or wider society views animals. We call this imaginary societal sentience. Against a backdrop of increasing ethnographic work on care encounters in the laboratory, this concept helps to stress the wider context within which such encounters take place. We conclude that societal sentience has potential purchase beyond the animal research field, in helping to highlight the affective dimension of public imaginaries (Welsh and Wynne 2013), and their ethical consequences. Researching and critiquing societal sentience, we argue, may ultimately have more impact on the fate of humans and non-humans in the laboratory, than focusing wholly on ethics as situated practice
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