24 research outputs found

    Effect of extended cefquinome treatment on clinical persistence or recurrence of environmental clinical mastitis

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    The effectiveness of antibiotic treatment of clinical mastitis (CM) is classically evaluated using bacteriological cure, which provides a concise and objective way of assessing efficacy but does not reflect the situation in the field where persistence or recurrence of clinical signs lead to perceived treatment failure. If clinical signs persist or recur, intramammary (IMM) treatment is often extended or supplemented with parenteral therapy in the expectation of a more efficient elimination of clinical signs or a lower probability of recurrence. The objective of this study was to evaluate the efficacy against clinical persistence or recurrence of three cefquinome treatment regimes, standard 1.5-day intramammary (SIMM), 5-day extended intramammary (EIMM) and combination of EIMM plus 5-day extended parenteral (ECOMBO) treatment. The study was conducted on three dairy farms with a high recurrence rate of environmental mastitis. Efficacy was evaluated using a multi-level model at the quarter and at the cow level, based on the persistence or recurrence of clinical signs at any time during a 105-day period following the end of the initial treatment, independent of pathogen. The most prevalent pathogens were E. coli (16.9%) and S. uberis (11.97%). EIMM and ECOMBO significantly decreased the persistence or recurrence of CM by 8% and 6% at the quarter level and by 9% and 8% at the cow level, respectively. ECOMBO may not reduce the persistence or recurrence of CM beyond EIMM. Whilst extended treatment regimens offered an improved outcome in this study, the producer and practitioner need to carefully consider such regimens from the perspective of prudent antibiotic use

    Active restoration accelerates the carbon recovery of human modified-tropical forests

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    More than half of all tropical forests are degraded by human impacts, leaving them threatened with conversion to agricultural plantations and risking substantial biodiversity and carbon losses. Restoration could accelerate recovery of aboveground carbon density (ACD), but adoption of restoration is constrained by cost and uncertainties over effectiveness. We report a long-term comparison of ACD recovery rates between naturally regenerating and actively restored logged tropical forests. Restoration enhanced decadal ACD recovery by more than 50%, from 2.9 to 4.4 megagrams per hectare per year. This magnitude of response, coupled with modal values of restoration costs globally, would require higher carbon prices to justify investment in restoration. However, carbon prices required to fulfill the 2016 Paris climate agreement [40to40 to 80 (USD) per tonne carbon dioxide equivalent] would provide an economic justification for tropical forest restoration

    Estimating aboveground carbon density and its uncertainty in Borneo's structurally complex tropical forests using airborne laser scanning

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    Borneo contains some of the world's most biodiverse and carbon-dense tropical forest, but this 750 000 km(2) island has lost 62% of its old-growth forests within the last 40 years. Efforts to protect and restore the remaining forests of Borneo hinge on recognizing the ecosystem services they provide, including their ability to store and sequester carbon. Airborne laser scanning (ALS) is a remote sensing technology that allows forest structural properties to be captured in great detail across vast geographic areas. In recent years ALS has been integrated into statewide assessments of forest carbon in Neotropical and African regions, but not yet in Asia. For this to happen new regional models need to be developed for estimating carbon stocks from ALS in tropical Asia, as the forests of this region are structurally and composition-ally distinct from those found elsewhere in the tropics. By combining ALS imagery with data from 173 permanent forest plots spanning the lowland rainforests of Sabah on the island of Borneo, we develop a simple yet general model for estimating forest carbon stocks using ALS-derived canopy height and canopy cover as input metrics. An advanced feature of this new model is the propagation of uncertainty in both ALS- and ground-based data, allowing uncertainty in hectare-scale estimates of carbon stocks to be quantified robustly. We show that the model effectively captures variation in aboveground carbon stocks across extreme disturbance gradients spanning tall dipterocarp forests and heavily logged regions and clearly outperforms existing ALS-based models calibrated for the tropics, as well as currently available satellite-derived products. Our model provides a simple, generalized and effective approach for mapping forest carbon stocks in Borneo and underpins ongoing efforts to safeguard and facilitate the restoration of its unique tropical forests.Peer reviewe

    Riparian buffers can help mitigate biodiversity declines in oil palm agriculture

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    Agricultural expansion drives biodiversity decline in forested tropical regions. Consequently, it is important to understand the conservation value of remnant forest in production landscapes. In a tropical landscape dominated by oil palm we characterized faunal communities across eight taxa occurring within riparian forest buffers, which are legally protected alongside rivers, and compared them to nearby recovering logged forest. Buffer width was the main predictor of species richness and abundance, with widths of 40-100 m on each side of the river supporting broadly equivalent levels of biodiversity to logged forest. However, width responses varied markedly among taxa, and buffers often lacked forest-dependent species. Much wider buffers than are currently mandated are needed to safeguard most species. The largest biodiversity gains are achieved by increasing relatively narrow buffers. To provide optimal conservation outcomes in tropical production landscapes we encourage policymakers to prescribe width requirements for key taxa and different landscape contexts.Newton-Ungku Omar Fund (grants 216433953, 537134717) – delivered by the British Council and funded by the UK Department for Business, Energy and Industrial Strategy and the Malaysian Industry-Government Group for High Technology – as well as the UK Natural Environment Research Council (NE/K016407/1, NE/K016261/1; https://lombok.nerc-hmtf.info/). MJS was supported by a Research Leadership Award from the Leverhulme Trust

    Higher predation risk for insect prey at low latitudes and elevations

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    Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution

    Conservation and the social sciences: Beyond critique and co-optation. A case study from orangutan conservation

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    Interactions between conservation and the social sciences are frequently characterized by either critique (of conservation by social scientists) or co-optation (of social scientific methods and insights by conservationists). This article seeks to push beyond these two dominant positions by exploring how conservationists and social scientists can engage in mutually transformative dialogue. Jointly authored by conservation scientists and social scientists, it uses the global nexus of orangutan conservation as a lens onto current challenges and possibilities facing the conservation–social science relationship. We begin with a cross-disciplinary overview of recent developments in orangutan conservation—particularly those concerned with its social, political and other human dimensions. The article then undertakes a synthetic analysis of key challenges in orangutan conservation—working across difference, juggling scales and contexts and dealing with politics and political economy—and links them to analogous concerns in the conservation–social science relationship. Finally, we identify some ways by which orangutan conservation specifically, and the conservation–social science relationship more generally, can move forward: through careful use of proxies as bridging devices, through the creation of new, shared spaces, and through a willingness to destabilize and overhaul status quos. This demands an open-ended, unavoidably political commitment to critical reflexivity and self-transformation on the part of both conservationists and social scientists.European Research Council Starting Grant 758494, Brunel University Londo

    3D visualization of HIV transfer at the virological synapse between dendritic cells and T cells

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    The efficiency of HIV infection is greatly enhanced when the virus is delivered at conjugates between CD4+ T cells and virus-bearing antigen-presenting cells such as macrophages or dendritic cells via specialized structures known as virological synapses. Using ion abrasion SEM, electron tomography, and superresolution light microscopy, we have analyzed the spatial architecture of cell-cell contacts and distribution of HIV virions at virological synapses formed between mature dendritic cells and T cells. We demonstrate the striking envelopment of T cells by sheet-like membrane extensions derived from mature dendritic cells, resulting in a shielded region for formation of virological synapses. Within the synapse, filopodial extensions emanating from CD4+ T cells make contact with HIV virions sequestered deep within a 3D network of surface-accessible compartments in the dendritic cell. Viruses are detected at the membrane surfaces of both dendritic cells and T cells, but virions are not released passively at the synapse; instead, virus transfer requires the engagement of T-cell CD4 receptors. The relative seclusion of T cells from the extracellular milieu, the burial of the site of HIV transfer, and the receptor-dependent initiation of virion transfer by T cells highlight unique aspects of cell-cell HIV transmission

    Data from: Higher predation risk for insect prey at low latitudes and elevations

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    Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution
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