4,802 research outputs found

    A systems approach to understanding the connection between farm systems resilience and pasture resilience

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    Farm systems resilience in New Zealand pasture-based farming is influenced by external drivers such as environmental regulation, and internal drivers such as existence, expressed as profitability. We examine ten published case studies of farm systems change to provide insight into management interventions to these drivers and their impacts on pasture resilience. Nutrient supply was key to increasing pasture longevity, water use efficiency and animal feed supply. Manipulating water use efficiency through irrigation and legume (predominantly lucerne) use increased nitrogen use efficiency and added pasture supply for animal consumption. Monitoring the pasture supply and animal response ensured both animal feed requirements and pasture conditions for future growth were met. The resilience of pastures was improved when monitoring guided adaptive management application to ensure whole-farm resilience

    The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs

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    The necks of sauropod dinosaurs were a key factor in their evolution. The habitual posture and range of motion of these necks has been controversial, and computer-aided studies have argued for an obligatory sub-horizontal pose. However, such studies are compromised by their failure to take into account the important role of intervertebral cartilage. This cartilage takes very different forms in different animals. Mammals and crocodilians have intervertebral discs, while birds have synovial joints in their necks. The form and thickness of cartilage varies significantly even among closely related taxa. We cannot yet tell whether the neck joints of sauropods more closely resembled those of birds or mammals. Inspection of CT scans showed cartilage:bone ratios of 4.5% for Sauroposeidon and about 20% and 15% for two juvenile Apatosaurus individuals. In extant animals, this ratio varied from 2.59% for the rhea to 24% for a juvenile giraffe. It is not yet possible to disentangle ontogenetic and taxonomic signals, but mammal cartilage is generally three times as thick as that of birds. Our most detailed work, on a turkey, yielded a cartilage:bone ratio of 4.56%. Articular cartilage also added 11% to the length of the turkey's zygapophyseal facets. Simple image manipulation suggests that incorporating 4.56% of neck cartilage into an intervertebral joint of a turkey raises neutral posture by 15°. If this were also true of sauropods, the true neutral pose of the neck would be much higher than has been depicted. An additional 11% of zygapophyseal facet length translates to 11% more range of motion at each joint. More precise quantitative results must await detailed modelling. In summary, including cartilage in our models of sauropod necks shows that they were longer, more elevated and more flexible than previously recognised

    The nature of X-ray-absorbed quasi-stellar objects

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    There exists a significant population of broad line, z∼ 2 quasi-stellar objects (QSOs) which have heavily absorbed X-ray spectra. Follow-up observations in the submillimetre show that these QSOs are embedded in ultraluminous starburst galaxies, unlike most unabsorbed QSOs at the same redshifts and luminosities. Here we present X-ray spectra from XMM–Newton for a sample of five such X-ray-absorbed QSOs that have been detected at submillimetre wavelengths. We also present spectra in the rest-frame ultraviolet from ground-based telescopes. All the five QSOs are found to exhibit strong C iv absorption lines in their ultraviolet spectra with equivalent width >5 Å. The X-ray spectra are inconsistent with the hypothesis that these objects show normal QSO continua absorbed by low-ionization gas. Instead, the spectra can be modelled successfully with ionized absorbers, or with cold absorbers if they possess unusually flat X-ray continuum shapes and unusual optical to X-ray spectral energy distributions. We show that the ionized absorber model provides the simplest, most self-consistent explanation for their observed properties. We estimate that the fraction of radiated power that is converted into kinetic luminosity of the outflowing winds is typically ∼4 per cent, in agreement with recent estimates for the kinetic feedback from QSOs required to produce the M–σ relation, and consistent with the hypothesis that the X-ray-absorbed QSOs represent the transition phase between obscured accretion and the luminous QSO phase in the evolution of massive galaxies

    Additional Clothing Increases Heat Load in Elite Female Rugby Sevens Players.

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    PURPOSE: To determine whether elite female rugby sevens players are exposed to core temperatures (Tc) during training in the heat that replicate the temperate match demands previously reported and to investigate whether additional clothing worn during a hot training session meaningfully increases the heat load experienced. METHODS: A randomized parallel-group study design was employed, with all players completing the same approximately 70-minute training session (27.5°C-34.8°C wet bulb globe temperature) and wearing a standardized training ensemble (synthetic rugby shorts and training tee [control (CON); n = 8]) or additional clothing (standardized training ensemble plus compression garments and full tracksuit [additional clothing (AC); n = 6]). Groupwise differences in Tc, sweat rate, GPS-measured external locomotive output, rating of perceived exertion, and perceptual thermal load were compared. RESULTS: Mean (P = .006, ηp2=.88) and peak (P 6 minutes. Additional clothing is a viable and effective method to increase heat strain in female rugby sevens players without compromising training specificity or external locomotive capacity

    An investigation of fingerstick blood collection for pointof- care HIV-1 viral load monitoring in South Africa

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    Background: Viral load (VL) quantification is an important tool in determining newly developed drug resistance or problems with adherence to antiretroviral therapy (ART) in HIV-positive patients. VL monitoring is becoming the standard of care in many resource-limited settings. Testing in resource-limited settings may require sampling by fingerstick because of general shortages of skilled phlebotomists and the expense of venepuncture supplies and problems with their distribution.Objective: To assess the feasibility and ease of collecting 150 μL capillary blood needed for the use of a novel collection device following a classic fingerstick puncture.Methods: Patients were recruited by the study nurse upon arrival for routine ART monitoring at the Themba Lethu Clinic in Johannesburg, South Africa. Each step of the fingerstick and blood collection protocol was observed, and their completion or omission was recorded.Results: One hundred and three patients consented to the study, of whom three were excluded owing to the presence of callouses. From a total of 100 patients who consented and were enrolled, 98% of collection attempts were successful and 86% of participants required only one fingerstick to successfully collect 150 μL capillary blood. Study nurse adherence to the fingerstick protocol revealed omissions in several steps that may lower the success rate of capillary blood collection and reduce the performance of a subsequent VL assay.Conclusion: The findings of this study support the feasibility of collecting 150 μL of capillary blood via fingerstick for point-of-care HIV-1 VL testing in a resource-limited setting

    Fluoxetine: a case history of its discovery and preclinical development

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    Introduction: Depression is a multifactorial mood disorder with a high prevalence worldwide. Until now, treatments for depression have focused on the inhibition of monoaminergic reuptake sites, which augment the bioavailability of monoamines in the CNS. Advances in drug discovery have widened the therapeutic options with the synthesis of so-called selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine. Areas covered: The aim of this case history is to describe and discuss the pharmacokinetic and pharmacodynamic profiles of fluoxetine, including its acute effects and the adaptive changes induced after long-term treatment. Furthermore, the authors review the effect of fluoxetine on neuroplasticity and adult neurogenesis. In addition, the article summarises the preclinical behavioural data available on fluoxetine’s effects on depressive-like behaviour, anxiety and cognition as well as its effects on other diseases. Finally, the article describes the seminal studies validating the antidepressant effects of fluoxetine. Expert opinion: Fluoxetine is the first selective SSRI that has a recognised clinical efficacy and safety profile. Since its discovery, other molecules that mimic its mechanism of action have been developed, commencing a new age in the treatment of depression. Fluoxetine has also demonstrated utility in the treatment of other disorders for which its prescription has now been approved

    The distribution of pond snail communities across a landscape: separating out the influence of spatial position from local habitat quality for ponds in south-east Northumberland, UK

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    Ponds support a rich biodiversity because the heterogeneity of individual ponds creates, at the landscape scale, a diversity of habitats for wildlife. The distribution of pond animals and plants will be influenced by both the local conditions within a pond and the spatial distribution of ponds across the landscape. Separating out the local from the spatial is difficult because the two are often linked. Pond snails are likely to be affected by both local conditions, e.g. water hardness, and spatial patterns, e.g. distance between ponds, but studies of snail communities struggle distinguishing between the two. In this study, communities of snails were recorded from 52 ponds in a biogeographically coherent landscape in north-east England. The distribution of snail communities was compared to local environments characterised by the macrophyte communities within each pond and to the spatial pattern of ponds throughout the landscape. Mantel tests were used to partial out the local versus the landscape respective influences. Snail communities became more similar in ponds that were closer together and in ponds with similar macrophyte communities as both the local and the landscape scale were important for this group of animals. Data were collected from several types of ponds, including those created on nature reserves specifically for wildlife, old field ponds (at least 150 years old) primarily created for watering livestock and subsidence ponds outside protected areas or amongst coastal dunes. No one pond type supported all the species. Larger, deeper ponds on nature reserves had the highest numbers of species within individual ponds but shallow, temporary sites on farm land supported a distinct temporary water fauna. The conservation of pond snails in this region requires a diversity of pond types rather than one idealised type and ponds scattered throughout the area at a variety of sites, not just concentrated on nature reserves

    Rossby wave dynamics of the North Pacific extra-tropical response to El Niño: importance of the basic state in coupled GCMs

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    The extra-tropical response to El Nino in a "low" horizontal resolution coupled climate model, typical of the Intergovernmental Panel on Climate Change fourth assessment report simulations, is shown to have serious systematic errors. A high resolution configuration of the same model has a much improved response that is similar to observations. The errors in the low resolution model are traced to an incorrect representation of the atmospheric teleconnection mechanism that controls the extra-tropical sea surface temperatures (SSTs) during El Nino. This is due to an unrealistic atmospheric mean state, which changes the propagation characteristics of Rossby waves. These erroneous upper tropospheric circulation anomalies then induce erroneous surface circulation features over the North Pacific. The associated surface wind speed and direction errors create erroneous surface flux and upwelling anomalies which finally lead to the incorrect extra-tropical SST response to El Nino in the low resolution model. This highlights the sensitivity of the climate response to a single link in a chain of complex climatic processes. The correct representation of these processes in the high resolution model indicates the importance of horizontal resolution in resolving such processes
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