1,616 research outputs found

    Correspondence between environmental gradients and summer littoral fish assemblages in low salinity reaches of the Chesapeake Bay, USA

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    Patterns in the assemblage structure of littoral fishes occupying the gradient between riverine and estuarine ecosystems were revealed through multivariate analysis of 5 annual summer seine surveys in 4 tributary systems of the lower Chesapeake Bay. Catch per unit effort of fishes was quantified and environmental variables measured to characterize assemblage structure and population responses along large-scale (km) environmental gradients. Results of two-way indicator species analysis (TWINSPAN), detrended correspondence analysis (DCA) and detrended canonical correspondence analysis (DCCA) suggested the presence of 4 intergrading assemblages of littoral beach fishes: permanent tidal freshwater, lower tidal freshwater, oligohaline estuary and mesohaline estuary. Littoral fish assemblages were ordered along a large-scale spatial gradient between tidal freshwater and mesohaline river reaches during summer, when relatively stable hydrological conditions create a well-defined salinity gradient. Large-scale distribution of these fishes along the liver axis corresponded with salinity (and its correlates) up to the interface, and with structural attributes of the habitat (nearshore sediment grain size, presence of submerged aquatic vegetation, woody debris) in the permanent tidal freshwater river reaches. The permanent tidal freshwater reaches were more riverine in character, and were typified by speciose and relatively stable assemblages dominated by resident secondary division freshwater fishes and the juveniles of several diadromous species. Although the resident fauna is certainly derivative of more upland, non-tidal streams. patterns of association suggest distinct ecological relationships may exist for species co-occurring in tidal freshwater habitats

    Behavioural plasticity by Eastern Grey Kangaroos in response to human behaviour

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    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Sharing landscapes with humans is an increasingly fraught challenge for wildlife across the globe. While some species benefit from humans by exploiting novel opportunities (e.g., provision of resources or removal of competitors or predators), many wildlife experience harmful effects, either directly through persecution or indirectly through loss of habitat. Consequently, some species have been shown to be attracted to human presence while others avoid us. For any given population of a single species, though, the question of whether they can recognise and change their response to human presence depending on the type of human actions (i.e., either positive or negative) has received little attention to date. In this study, we chose to examine the behavioural plasticity within a single population of eastern grey kangaroos (Macropus giganteus) to both positive and negative human activity. Within a relatively small and contiguous landscape, we identified areas where kangaroos experience a combination of either low and high frequencies of benign and harmful human disturbances. From six sampling sessions over five months, we found that density and group sizes were higher where humans acted benignly towards them, and that these groups had higher representations of sub-adults and juveniles than where humans had harmful intentions. Importantly, we found that the vital antipredator strategy of increasing group size with distance from cover was not detectable at sites with low and high levels of harm. Our findings suggest that these kangaroos are recognising and adjusting their behavioural response to humans at fine spatial scales, a plasticity trait that may be key to the survival of these species in human dominated landscapes

    Observable essential fatty acid deficiency markers and autism spectrum disorder

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    Autism Spectrum Disorder (ASD) has been associated with essential fatty acid (EFA) deficiencies, with some researchers theorising that dysregulation of phospholipid metabolism may form part of the biological basis for ASD. This pilot study compared observable signs of fatty acid status of 19 children with an ASD diagnosis to 23 of their typically developing siblings. A pregnancy, birth and breastfeeding history was also obtained from their parents, which included a measure of infant intake of fatty acid rich colostrum immediately post-partum. When considered within their family group, those infants not breastfed (with colostrum) within the first hour of life and who had a history of fatty acid deficiency symptoms were more likely to have an ASD diagnosis. Other variables such as formula use, duration of breastfeeding, gestational age and Apgar scores were not associated with group membership. The results of this study are consistent with previous research showing a relationship between fatty acid metabolism, breastfeeding and ASD such that early infant feeding practices and the influence this has on the fatty acid metabolism of the child may be a risk factor for ASD

    Inclusion and Independence: The impact of Mobile Technology on the Lives of Persons with Disabilities in Kenya and Bangladesh

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    Globally, mobile technology plays a significant role connecting and supporting people with disabilities. However, there has been limited research focused on understanding the impact of mobile technology in the lives of persons with disabilities in low or middle- income countries. This paper presents the findings of a participatory photovoice study looking at the role that mobile phones play in the daily lives of 16 persons with disabilities in Kenya and Bangladesh. Participants used a combination of pictures and voice recordings to capture their own stories and illustrate the impact that mobile phone use has on their lives. Through thematic analysis, we categorized the benefits of mobile phones captured by participants as 1) Improved social connection; 2) Increased independence and 3) Access to opportunities. While mobile phones are ubiquitously used for communication, for persons with disabilities they become essential assistive technologies that bridge barriers to opportunities which are not accessible otherwise. Our paper adds evidence to the need for mobile phones for persons with disabilities to enable communication and connectivity in support of development

    Yield and Viability of Human Limbal Stem Cells From Fresh and Stored Tissue

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    Purpose: We compared cell number, putative stem cell markers, and clonogenic ability in fresh uncultured human limbal epithelial cells to that obtained from stored organ-cultured tissue. Methods: Cell suspensions were formed from fresh and organ culture–stored human limbal epithelium. Expression of putative stem cell markers ΔNp63 and TrkA was performed using immunofluorescent staining before culture. Colony-forming efficiency (CFE) assays were performed at first passage. The effects of tissue storage, age, and postmortem/culture times were analyzed in a general linear model. Results: Limbal tissue from 94 donors (34 fresh and 60 stored) was compared. Three times more cells were obtained per eye from fresh (35.34 × 104; SD, 17.39) than stored (11.24 × 104; SD, 11.57; P < 0.01) tissue. A higher proportion of cells from fresh tissue were viable (91.9%; SD, 5.7 vs. 85%; SD, 10.8) P < 0.01. Higher total cell expression of ΔNp63 (20.19 × 104; SD, 15.5 vs. 3.28 104; SD, 4.33) and TrkA (59.24 × 104; SD, 13.21 vs. 7.65 × 104; SD, 1.05) was observed in fresh than stored tissue (P < 0.01). Colony-forming efficiency was higher for fresh (1.42; SD, 0.12) than stored (0.43; SD, 0.15; P < 0.01) cells. For stored tissue only, there was a significant inverse relationship between donor age and total number of cells isolated (R2 = 0.27, P < 0.001). Conclusions: Storage of corneoscleral discs in organ culture medium leads to significant reduction in limbal epithelial cell number, expression of ΔNp63 and TrkA, and viability compared to fresh tissue. There is a smaller basal stem cell population in stored compared to fresh tissue

    On high-speed turning of a third-generation gamma titanium aluminide

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    Gamma titanium aluminides are heat-resistant intermetallic alloys predestined to be employed in components suffering from high mechanical stresses and thermal loads. These materials are regarded as difficult to cut, so this makes process adaptation essential in order to obtain high-quality and defect-free surfaces suitable for aerospace and automotive parts. In this paper, an innovative approach for longitudinal external high-speed turning of a third-generation Ti-45Al-8Nb- 0.2C-0.2B gamma titanium aluminide is presented. The experimental campaign has been executed with different process parameters, tool geometries and lubrication conditions. The results are discussed in terms of surface roughness/integrity, chip morphology, cutting forces and tool wear. Experimental evidence showed that, due to the high cutting speed, the high temperatures reached in the shear zone improve chip formation, so a crack-free surface can be obtained. Furthermore, the use of a cryogenic lubrication system has been identified in order to reduce the huge tool wear, which represents the main drawback when machining gamma titanium aluminides under the chosen process condition

    Fjords as Aquatic Critical Zones (ACZs)

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    In recent decades, the land-ocean aquatic continuum, commonly defined as the interface, or transition zone, between terrestrial ecosystems and the open ocean, has undergone dramatic changes. On-going work has stressed the importance of treating Aquatic Critical Zones (ACZs) as a sensitive system needing intensive investigation. Here, we discuss fjords as an ACZ in the context of sedimentological, geochemical, and climatic impacts. These diverse physical features of fjords are key in controlling the sources, transport, and burial of organic matter in the modern era and over the Holocene. High sediment accumulation rates in fjord sediments allow for high-resolution records of past climate and environmental change where multiple proxies can be applied to fjord sediments that focus on either marine or terrestrial-derived components. Humans through land-use change and climatic stressors are having an impact on the larger carbon stores in fjords. Sediment delivery whether from accelerating erosion (e.g. mining, deforestation, road building, agriculture) or from sequestration of fluvial sediment behind dams has been seriously altered in the Anthropocene. Climate change affecting rainfall and river discharge into fjords will impact the thickness and extent of the low-salinity layer in the upper reaches of the fjord, slowing the rate of the overturning circulation and deep-water renewal – thereby impacting bottom water oxygen concentrations

    Diagnosis, therapeutic advances, and key recommendations for the management of factor X deficiency.

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    Factor X deficiency is a rare coagulation disorder that can be hereditary or acquired. The typology and severity of the associated bleeding symptoms are highly heterogeneous, adding to the difficulties of diagnosis and management. Evidence-based guidelines and reviews on factor X deficiency are generally limited to publications covering a range of rare bleeding disorders. Here we provide a comprehensive review of the literature on factor X deficiency, focusing on the hereditary form, and discuss the evolution in disease management and the evidence associated with available treatment options. Current recommendations advise clinicians to use single-factor replacement therapy for hereditary disease rather than multifactor therapies such as fresh frozen plasma, cryoprecipitate, and prothrombin complex concentrates. Consensus in treatment guidelines is still urgently needed to ensure optimal management of patients with factor X deficiency across the spectrum of disease severity

    Designing a complex intervention for dementia case management in primary care

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    Background: Community-based support will become increasingly important for people with dementia, but currently services are fragmented and the quality of care is variable. Case management is a popular approach to care co-ordination, but evidence to date on its effectiveness in dementia has been equivocal. Case management interventions need to be designed to overcome obstacles to care co-ordination and maximise benefit. A successful case management methodology was adapted from the United States (US) version for use in English primary care, with a view to a definitive trial. Medical Research Council guidance on the development of complex interventions was implemented in the adaptation process, to capture the skill sets, person characteristics and learning needs of primary care based case managers. Methods: Co-design of the case manager role in a single NHS provider organisation, with external peer review by professionals and carers, in an iterative technology development process. Results: The generic skills and personal attributes were described for practice nurses taking up the case manager role in their workplaces, and for social workers seconded to general practice teams, together with a method of assessing their learning needs. A manual of information material for people with dementia and their family carers was also created using the US intervention as its source. Conclusions: Co-design produces rich products that have face validity and map onto the complexities of dementia and of health and care services. The feasibility of the case manager role, as described and defined by this process, needs evaluation in ‘real life’ settings
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