176 research outputs found

    Understanding trade pathways to target biosecurity surveillance

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    Increasing trends in global trade make it extremely difficult to prevent the entry of all potential invasive species (IS). Establishing early detection strategies thus becomes an important part of the continuum used to reduce the introduction of invasive species. One part necessary to ensure the success of these strategies is the determination of priority survey areas based on invasion pressure. We used a pathway-centred conceptual model of pest invasion to address these questions: what role does global trade play in invasion pressure of plant ecosystems and how could an understanding of this role be used to enhance early detection strategies? We concluded that the relative level of invasion pressure for destination ecosystems can be influenced by the intensity of pathway usage (import volume and frequency), the number and type of pathways with a similar destination, and the number of different ecological regions that serve as the source for imports to the same destination. As these factors increase, pressure typically intensifies because of increasing a) propagule pressure, b) likelihood of transporting pests with higher intrinsic invasion potential, and c) likelihood of transporting pests into ecosystems with higher invasibility. We used maritime containerized imports of live plants into the contiguous U.S. as a case study to illustrate the practical implications of the model to determine hotspot areas of relative invasion pressure for agricultural and forest ecosystems (two ecosystems with high potential invasibility). Our results illustrated the importance of how a pathway-centred model could be used to highlight potential target areas for early detection strategies for IS. Many of the hotspots in agricultural and forest ecosystems were within major U.S. metropolitan areas. Invasion ecologists can utilize pathway-centred conceptual models to a) better understand the role of human-mediated pathways in pest establishment, b) enhance current methodologies for IS risk analysis, and c) develop strategies for IS early detection-rapid response programs

    Simulation and Design of an Orientation Mechanism for Assembly Systems

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    The article focuses on methods for designing modular cable-driven orientation mechanisms that can be attached to robot systems that lack on rotational degrees of freedom. The approach yields assembly systems for high speed handling applications by reducing moving masses. For this purpose, a classification of feasible kinematic structures are given and resulting characteristics, like the orientation workspace, dexterity or its homogeneity, are analyzed. The mechanical design of a first prototype is subsequently presented along with a universal simulation tool for determining task-adapted powertrains using cables. Finally, results of first tests and possibilities for future developments are presented. © 2016 The Authors

    Zonas globais de resistência às plantas para análise de risco fitossanitário

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    Plant hardiness zones are widely used for selection of perennial plants and for phytosanitary risk analysis. The most widely used definition of plant hardiness zones (United States Department of Agriculture National Arboretum) is based on average annual extreme minimum temperature. There is a need for a global plant hardiness map to standardize the comparison of zones for phytosanitary risk analysis. Two data sets were used to create global hardiness zones: i) Climate Research Unit (CRU) 1973-2002 monthly data set; and ii) the Daily Global Historical Climatology Network (GHCN). The CRU monthly data set was downscaled to five-minute resolution and a cubic spline was used to convert the monthly values into daily values. The GHCN data were subjected to a number of quality control measures prior to analysis. Least squares regression relationships were developed using GHCN and derived lowest average daily minimum temperature data and average annual extreme minimum temperatures. Error estimate statistics were calculated from the numerical difference between the estimated value for the grid and the station. The mean absolute error for annual extreme minimum temperature was 1.9ºC (3.5ºF) and 2/3 of the stations were classified into the correct zone.Zonas de resistência às plantas, definidas pelo " United States Department of Agriculture National Arboretum" com base na média anual das temperaturas mínimas extremas, são amplamente utilizadas para a seleção de plantas perenes e para a análise de risco fitossanitário. Há necessidade de um mapa global para padronizar a comparação de zonas nas análises de risco fitossanitário. Dois bancos de dados climatológicos foram utilizados para criar tais zonas globais de resistência às plantas: i) conjunto de dados mensais de 1973-2002 da " Climate Research Unit (CRU)" ; e ii) dados climatológicos diários da " Daily Global Historical Climatology Network (GHCN)" . Os dados mensais da CRU foram ajustados a uma escala reduzida de resolução de cinco minutos, e um ajuste cúbico foi empregado para converter os dados mensais para diários. Os dados da RDGH foram submetidos a várias medidas de controle de qualidade antes de serem empregados nas análises. Relações de regressão pelo método dos mínimos quadrados foram desenvolvidas usando dados da RDGH, resultando nos mais baixos valores médios diários de temperatura mínima e média anual das temperaturas mínimas extremas. Os erros estatísticos estimados foram calculados a partir da diferença numérica entre os valores estimados para a malha e os observados nas estações climatológicas. O erro médio absoluto para a temperatura mínima extrema anual foi 1,9ºC (3,5ºF), o que possibilitou a classificação de 2/3 das estações dentro das zonas corretas

    Accelerating bioprocess development by analysis of all available data: A USP case study

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    datasets (e.g. time series, quality measurements). By analyzing all available data, bioprocess development can be accelerated. This can only be achieved by having a clearly defined data logging and analysis strategy. Here, we present a case study using available data from the development and optimization of the upstream process (USP) of Sabin inactivated polio vaccine (IPV) using animal component free medium. IPV production using attenuated Sabin strains instead of wild type polio viruses is an initiative supported by the World Health Organization. This change is favorable to reduce the risk of outbreaks during IPV production. Optimizing this process using only animal free components reduces operational costs and lowers the risk of adverse effects related to animal derived compounds. During the process development, 40 bioreactors at scales ranging from 2.3 to 16 L were run. For optimization and robustness studies, design of experiments (DoE) was performed and several USP operational parameters were varied. These included operational mode (batch vs semi-batch), multiplicity of infection (MOI) and time of infection (TOI). This data was routinely analyzed using factors based on DoE methodology. With the new strategy, it became possible to scrutinize all data from the 40 USP development runs in a single data study. The total data package that was analyzed; this included the DoE response parameters, all offline data (e.g. cell, substrate and product concentrations), all data generated by the bioreactor control systems (T, pH, DO, DOCO), and derived calculations (specific rates like µ and qglu). This analysis showed which parameters were most important regarding the bioreactor performance. This USP case study showed that with the new strategy a more detailed, reliable and exact view on the most important parameters regarding bioreactor performance could be obtained. In order to do this, a feature based approach supported by the inCyght® software was utilized. It consisted of logging all data into a database, which was used to determine data integrity for all variables and batches. Exact phase information (cell growth, virus production phase) and other meta information are transferred into the database for each batch. This allowed outliers to be visually determined and certain variables to be excluded from the analysis (i.e. those that did not fluctuate). Univariate outlier detection technique was used to further determine outliers. Principal component analysis (PCA) was used to gain a multivariate process understanding and partial least squares (PLS) regression was performed to identify correlations. This result determined the best subset of variables to be fitted by using multiple linear regression (MLR). Future experiments will focus on the relevant parameters highlighted by this approach. This strategy was applied for the analysis of previously produced data. Further development will use this data analysis methodology for continuous accelerated process development, intensified DoE and integrated process modelling

    Marburg hemorrhagic fever in Durba and Watsa, Democratic Republic of the Congo: clinical documentation, features of illness, and treatment

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    The objective of the present study was to describe day of onset and duration of symptoms of Marburg hemorrhagic fever (MHF), to summarize the treatments applied, and to assess the quality of clinical documentation. Surveillance and clinical records of 77 patients with MHF cases were reviewed. Initial symptoms included fever, headache, general pain, nausea, vomiting, and anorexia (median day of onset, day 1-2), followed by hemorrhagic manifestations (day 5-8+), and terminal symptoms included confusion, agitation, coma, anuria, and shock. Treatment in isolation wards was acceptable, but the quality of clinical documentation was unsatisfactory. Improved clinical documentation is necessary for a basic evaluation of supportive treatment

    Picosecond x-ray magnetic circular dichroism spectroscopy at the Fe L-edges with a laser-driven plasma source

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    Time-resolved x-ray magnetic circular dichroism (XMCD) enables a unique spectroscopic view on complex spin and charge dynamics in multi-elemental magnetic materials. So far, its application in the soft-x-ray range has been limited to synchrotron-radiation sources and free-electron lasers. By combining a laser-driven plasma source with a magnetic thin-film polarizer, we generate circularly polarized photons in the soft x-ray regime, enabling the first XMCD spectroscopy at the Fe L edges in a laser laboratory. Our approach can be readily adapted to other transition metal L and rare earth M absorption edges and with a temporal resolution of < 10 ps, a wide range of ultrafast magnetization studies can be realized.Comment: 7 pages, 4 figures, supplemental materia

    Synthetic CO emission and the XCOX_{\rm CO} factor of young molecular clouds: a convergence study

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    The properties of synthetic CO emission from 3D simulations of forming molecular clouds are studied within the SILCC-Zoom project. Since the time scales of cloud evolution and molecule formation are comparable, the simulations include a live chemical network. Two sets of simulations with an increasing spatial resolution (dx=3.9x=3.9 pc to dx=0.06x=0.06 pc) are used to investigate the convergence of the synthetic CO emission, which is computed by post-processing the simulation data with the RADMC-3D radiative transfer code. To determine the excitation conditions, it is necessary to include atomic hydrogen and helium alongside H2_2, which increases the resulting CO emission by ~7-26 per cent. Combining the brightness temperature of 12^{12}CO and 13^{13}CO, we compare different methods to estimate the excitation temperature, the optical depth of the CO line and hence, the CO column density. An intensity-weighted average excitation temperature results in the most accurate estimate of the total CO mass. When the pixel-based excitation temperature is used to calculate the CO mass, it is over-/underestimated at low/high CO column densities where the assumption that 12^{12}CO is optically thick while 13^{13}CO is optically thin is not valid. Further, in order to obtain a converged total CO luminosity and hence factor, the 3D simulation must have dx0.1x\lesssim0.1 pc. The evolves over time and differs for the two clouds; yet pronounced differences with numerical resolution are found. Since high column density regions with a visual extinction larger than 3~mag are not resolved for dx1x\gtrsim 1~pc, in this case the H2_2 mass and CO luminosity both differ significantly from the higher resolution results and the local XCOX_{\rm CO} is subject to strong noise. Our calculations suggest that synthetic CO emission maps are only converged for simulations with dx0.1x\lesssim 0.1 pc.Comment: 23 pages, 22 figures, accepted for publication in MNRA

    DESENVOLVIMENTO SUSTENTÁVEL E DESIGN: UMA RELAÇÃO QUE VISA A SUSTENTABILIDADE

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    Considerando a situação do planeta, tendo em vista a ação nefasta do ser humano, agravada pelo consumismo desenfreado, a falta de educação ambiental e o consequente desrespeito a natureza, este estudo se propõe a analisar o papel do design como fomentador do desenvolvimento sustentável. Para tal, primeiramente será conceituado o desenvolvimento sustentável em suas diferentes dimensões. A transformação do modelo atual de desenvolvimento requer um esforço coletivo. Nesse sentido, precisam assumir os princípios da sustentabilidade: o governo, os cidadãos e também as empresas que devem produzir produtos que respeitem o meio ambiente, utilizando conceitos de Design para a sustentabilidade
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