1,093 research outputs found

    Simulation of landsat thematic mapper imagery using AVIRIS hyperspectral imagery

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    In this paper we present a methodology for simulating multispectral imagery (MSI) using hyperspectral imagery (HSI), and present a validation of the technique using one nearly coincident Landsat TM and AVIRIS data set. Generation of MSI from HSI supports several investigations including selection of multispectral sensor band edges, and engineering trade studies related to on-board or ground-based aggregation of HSI to simulate MSI. In addition, the utility of this technique as a potential procedure for monitoring calibration changes in spaceborne instrument is also addressed

    How to link people, government, and science in effective large-scale management of invasive trees

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    A common limitation for the effective management of widespread non-native species is translating and implementing the latest scientific knowledge for practitioners. Non-native tree invasions are no exception to this problem. We illustrate how the National Wilding Conifer Control Programme in New Zealand has worked to overcome these limitations through a partnership approach, ensuring affected communities are connected to on-the-ground responses, and facilitating the transfer of new scientific knowledge to practitioners. By ensuring the overarching management strategy was developed collaboratively with clear, mutually-agreed goals, the programme has helped to unite diverse stakeholders with a common purpose. Although coordinated by a central government body, the governance structure is sufficiently flexible to address the specific management needs of each affected community. The programme takes an adaptive management approach that enables multiple lines of research and management to be developed together; this is essential to improve management across different regions and stages of invasion. A co-developed strategy, partnership structure, and adaptive management were each critical components of the National Wilding Conifer Control Programme. However, there are ongoing challenges to overcome, such as securing long-term funding and reducing risks of re-invasion, to meet the ultimate goal of containing conifer invasions nationally. We suggest that lessons from this programme provide general insights into how linking people, government, and science could be used to improve the effectiveness of large-scale invasive non-native species management elsewhere

    Feasibility of an Acoustophoresis-based System for a High-Throughput Cell Washing: Application to Bioproduction

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    Background These last decades have seen the emergence and development of cell-based therapies, notably those based on mesenchymal stromal cells (MSCs). The advancement of these promising treatments requires increasing the throughput of processed cell for industrialization in order to reduce production costs. Among the various bioproduction challenges, downstream processing (DSP), including medium exchange, cell washing, cell harvesting and volume reduction, remains a critical step on which improvements are needed. Typically, these processes are performed by centrifugation. However, this approach limits the automation, especially in small batch productions where it is performed manually in open system. Methods An acoustophoresis-based system was developed for cell washing. The cells were transferred from one stream to another via the acoustic forces and were collected in a different medium. The optimal flow rates of the different streams were assessed using Red Blood Cells (RBCs) suspended in an albumin solution. Finally, the impact of acoustic washing on adipose tissue-derived MSCs (AD-MSCs) transcriptome was investigated by RNA-sequencing. Results With a single passage through the acoustic device at input flow rate of 45 mL/h, the albumin removal was up to 90% while recovering 99% of RBCs. To further increase the protein removal, a loop washing in two steps was performed and has allowed an albumin removal ≥\ge99% and a RBCs/AD-MSCs recovery of 99%. After loop washing of AD-MSCs, only 2 genes, HES4 and MIR-3648-1, were differently expressed compared to the input. Conclusion In this study, we developed a continuous cell washing system based on acoustophoresis. The process allows a high cell throughput while inducing little gene expression changes. These results highly suggest that cell washing based on acoustophoresis is a relevant and promising solution for numerous applications in cell manufacturing

    Local conditions vs regional context: variation in composition of bird communities along the Middle Paraná River, an extensive river-floodplain system of South America

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    We studied spatial changes in species composition (i.e., beta diversity) of local assemblages of birds along ∼450 km of the Middle Paraná River, an extensive fluvial system of South America. Point counts were used to survey birds at 60 plots located in shrub swamps and marshes of the floodplain within four sites (15 plots per site). Two sites were surrounded by each of the two upland ecoregions. Beta diversity of bird assemblages was high and was more important than alpha diversity in shaping regional diversity (i.e., gamma diversity) of the fluvial system. Compositional changes were related to species turnover among plots, while nestedness dissimilarity was not important for shaping diversity patterns. Variation-partitioning analysis showed that local conditions (i.e., landscape composition within a radius of 200 m from the center of each plot) accounted for more spatial variation in assemblage composition than did location along the fluvial system. Adjacent upland ecoregions did not account for spatial changes in bird composition within the fluvial system. In conclusion, environmental heterogeneity created by flood pulses is an important factor for sustaining regional diversity of birds within the fluvial system through effects on beta diversity

    Report and policy brief: 2nd Annual Conference on Social Aspects of HIV/AIDS Research, Cape Town, 9 - 12 May 2004

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    This report and policy brief summarises the overarching principles, key findings and suggested policy options that emerged from rapporteur reports of conference proceedings of the 2nd Annual Conference on Social Aspects of HIV/AIDS Research, Cape Town, 9 - 12 May 2004. SAHARA-J (2004) 1(2): 62-77 Keywords: SAHARA Network, Conference proceedings, Policy brief, HIV, AIDS, Sub-Saharan Africa, reseach, Social aspects. RÉSUMÉ Ce dossier de rapport et de politique présente un compte-rendu des principes dominants, des conclusions principales et des options d'une politique proposée qui font partie des communications présentées de la 2è Conférence Annuelle de Recherche sur les Aspects Sociaux du VIH/SIDA, le Cap, 9 - 12 mai 2004. SAHARA-J (2004) 1(2): 62-77 Mots clés: Réseau du SAHARA, démarches de conférence, dossier de politique, HIV/AIDS, Afrique Secondaire-Saharan, reseach, aspects sociaux

    Gas hydrate measurements at Hydrate Ridge using Raman spectroscopy

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    Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 71: 2947-2959, doi:10.1016/j.gca.2007.03.032.Oceanic gas hydrates have been measured near the seafloor for the first time using a seagoing Raman spectrometer at Hydrate Ridge, Oregon, where extensive layers of hydrates have been found to occur near the seafloor. All of the hydrates analyzed were liberated from the upper meter of the sediment column near active gas venting sites in water depths of 770-780 m. Hydrate properties, such as structure and composition, were measured with significantly less disturbance to the sample than would be realized with core recovery. The natural hydrates measured were sI, with methane as the predominant guest component, and minor/trace amounts of hydrogen sulfide present in three of the twelve samples measured. Methane large-to-small cage occupancy ratios of the hydrates varied from 1.01 to 1.30, in good agreement with measurements of laboratory synthesized and recovered natural hydrates. Although the samples visually appeared to be solid, varying quantities of free methane gas were detected, indicating the presence of occluded gas a hydrate bubble fabric and/or partial hydrate dissociation in the under-saturated seawater.This work was supported through National Undersea Research Program grant UAF03-0098. DORISS and PUP development was funded by a grant to MBARI from the David and Lucile Packard Foundation

    Non-Native Plants Disrupt Dual Promotion of Native Alpha and Beta Diversity

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    Abstract Non-native species can alter patterns of species diversity at multiple spatial scales, but the processes that underlie multi-scale effects remain unclear. Here we show that non-native species reduce native diversity at multiple scales through simultaneous disruption of two processes of native community assembly: species immigration, which enhances alpha diversity, and community divergence, which enhances beta diversity. Community divergence refers to the process in which local communities diverge over time in species composition because the history of species immigration and, consequently, the way species affect one another within communities are variable among communities. Continuous experimental removal of species over four years of floodplain succession revealed that, when non-native species were excluded, stochastic variation in the timing of a dominant native species' arrival allowed local communities to diverge, thereby enhancing beta diversity, without compromising promotion of alpha diversity by species immigration. In contrast, when non-native species were allowed to enter experimental plots, they not only reduced native alpha diversity by limiting immigration, but also diminished the dominant native species' role in enhancing native beta diversity. Our results highlight the importance of community assembly and succession for understanding multi-scale effects of non-native species

    Prevalence, circumstances and consequences of non-fatal road traffi c injuries and other bodily injuries among older people in China, Ghana, India, Mexico, Russia and South Africa

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    Unintentional injuries are one of the main contributors to mortality and disability in elderly populations in low- and middle-income countries. The aim of this study was to examine the annual road traffic and other bodily (not including falls) injury prevalence and associated risk factors among older adults across six lower and upper middle-income countries. A cross- sectional survey involving face-to-face household interviews were conducted in China (n=13,177), Ghana (n=4305), India (n=6560), Mexico (n=2318), the Russian Federation (n=3938) and South Africa (n=3840), resulting in population-based cohorts of persons aged 50+ years.  Measures included questions on injury, self-rated visual difficulties, alcohol use, depression treatment, sleeping problems, self-reported health status, and vision assessment using LogMAR (logarithm of Minimum Angle of Resolution) eye charts. It comprises rows of letters and is used to measure visual acuity. Results indicate that the overall annual non-fatal road traffic injury prevalence was 2.0% and for other bodily injury 2.1% (not including falls) across the six countries. The multivariate logistic regression analysis found that residing in a rural area, taking medications or other treatment for depression in the past 12 months and having a sleeping problem were associated with road traffic injury, while younger age, residing in a rural area, hazardous or harmful alcohol use and having a sleeping problem were associated with other bodily injury. Visual impairment was not associated with prevalence of road traffic injuries. This study provides the burden of non-fatal road traffic injury and other bodily injury and their associated risk factors across the six countries’ studies. The findings of this study improves the understanding of non-fatal road traffic injury and other bodily injury upon which policy makers, programme developers and researchers in public health can design strategic interventions to reduce these preventable injuries as well as improve safety associated with unintentional injuries.Keywords: injury, traffic, ageing, China, Ghana, India, Mexico, Russian Federation, South Africa

    LAPW frozen-phonon calculation, shell model lattice dynamics and specific-heat measurement of SnO

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    An ab-initio Linear Augmented Plane-Wave (LAPW) calculation of the zone-centered phonon frequencies of SnO has been performed. Eg_g symmetry has been ascribed to the mode observed at 113 cm−1^{-1} in Raman measurements, discarding a previous B1g_{1g} assignement. The other phonon modes measured by Raman spectroscopy are also well reproduced. A new shell-model has also been developed, that gives good agreement of the zone-centered frequencies compared to the measured data and the LAPW results. Specific heat measurements have been performed between 5 K and 110 K. Computation of the specific heat and the M\"{o}ssbauer recoilless fraction with the improved shell-model shows a good agreement with the experimental data as a function of temperature.Comment: 11 pages, 1 figure. to appear in Phys. Rev. B (November 1999
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