804 research outputs found

    Pressure probe compensates for dimensional tolerance variations

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    Flexible, compressible spring-loaded pressure probe measures the static pressure between the rotor stages on an axial-flow fuel pump. This probe is used in installation where a drilled static pressure tap or a rigid impulse tube cannot be used. Its parameters must be specially determined for each installation

    Designing Regional Systems of Biotechnology Regulation A Transaction Cost Approach to Regulatory Governance

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    Many developing countries are currently in the process of designing regulatory systems that should make it possible to use the potential of genetically modified organisms (GMOs) for agricultural development, while at the same time managing the risks for food safety and the environment that are potentially associated with these technologies. In view of the considerable costs associated with biotechnology regulation and the scarcity of biosafety specialists, there are processes in various regions of the developing world to establish regional systems of biotechnology regulation. So far, there are major knowledge gaps as to how regional systems of biotechnology regulation can be designed to be effective and efficient and to fulfill principles of good governance, such as transparency, voice and accountability, control of corruption, and avoidance of special interest capture. There is a wide variety of possible regional approaches, which differ with regard to the level of centralization, the scope of a regional system, the types of regional institutions and processes, and the types of financing mechanisms. Based on the literature on environmental and fiscal federalism and transaction costs economics, the paper develops a conceptual framework for the assessment of regional systems of biotechnology regulation. The framework specifies design options and assessment criteria, and identifies major trade-offs as well as the factors affecting these trade-offs. The paper takes West Africa as an example to illustrate this framework and refers to the European Union for comparison. The paper concludes that involving regional experts, stakeholders and policy-makers into debates on the design of a regional regulatory system is an important strategy to fill knowledge gaps and arrive at conclusions regarding the trade-offs involved in regional biotechnology regulation. Key words: regional biotechnology regulation; regulatory federalism; transaction cost economics; West Africa; European Unionregional biotechnology regulation, regulatory federalism, transaction cost economics, European Union, Agricultural and Food Policy, Community/Rural/Urban Development, Consumer/Household Economics, Environmental Economics and Policy, Farm Management, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, International Relations/Trade, Marketing, Production Economics, Research and Development/Tech Change/Emerging Technologies,

    Development of a relatchable cover mechanism for a cryogenic IR-sensor

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    A cover mechanism for use on the Infrared Background Signature Survey (IBSS) cryostat was developed. The IBSS IR-instrument is scheduled for STS launch in early 1991 as a payload of the Shuttle Payload Satellite (SPS) 2. The cover is hinged, with a motorized rope drive. During ground processing, launch, entry, and landing, the cryostat, which houses the IR-instrument, is required to be a sealed vacuum tight container for cooling purposes and contamination prevention. When on orbit, the cover is opened to provide an unobstructed field of view for the IR-instrument. A positive seal is accomplished through the use of latch mechanism. The cover and the latch are driven by a common redundant actuator consisting of dc motors, spur gears, and a differential gear. Hall probe limit switches and position sensors (rotary variable transformer) are used to determine the position of the cover and the latch. The cover mechanism was successfully qualified for thermal vacuum (-25 to 35 C), acoustic noise, vibration (6 Gs sine, 9.7 G RMS) and life cycles. Constricting requirements, mechanical and electronic control design, specific design details, test results of functional performance, and environmental and life tests are described

    On the structural changes in the Brewer-Dobson circulation after 2000

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    In this paper we present evidence that the observed increase in tropical upwelling after the year 2000 may be attributed to a change in the Brewer-Dobson circulation pattern. For this purpose, we use the concept of transit times derived from residual circulation trajectories and different in-situ measurements of ozone and nitrous dioxide. Observations from the Canadian midlatitude ozone profile record, probability density functions of in-situ N2O observations and a shift of the N2O-O3 correlation slopes, taken together, indicate that the increased upwelling in the tropics after the year 2000 appears to have triggered an intensification of tracer transport from the tropics into the extratropics in the lower stratosphere below about 500 K. This finding is corroborated by the fact that transit times along the shallow branch of the residual circulation into the LMS have decreased for the same time period (1993–2003). On a longer time scale (1979–2009), the transit time of the shallow residual circulation branch show a steady decrease of about −1 month/decade over the last 30 years, while the transit times of the deep branch remain unchanged. This highlights the fact that a change in the upwelling across the tropical tropopause is not a direct indicator for changes of the whole Brewer-Dobson circulation

    Analysis for biotechnology innovations using Strategic Environmental Assessment (SEA):

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    " Meeting the food needs of the world's growing population while reducing poverty and protecting the environment is a major global challenge. Genetically modified crops appear to provide a promising option to deal with this challenge. However there is a need to make strategic decisions on how to spend limited agricultural research funds in order to achieve a maximum impact with regard to finding sustainable solutions to end hunger and poverty. In international development institutions, there is growing interest in the potential use of Strategic Environmental Assessment (SEA) as part of a research based Environmental Management System (EMS) to promote mainstreaming of environmental considerations in policy development. SEA was developed as an approach to integrate environmental considerations at a policy level, where alternatives environmental policies can be evaluated. In this paper, we propose using SEA in a policy research and priority setting process regarding new technologies, taking the development of Genetically Modified Organisms (GMOs) as an example. We propose that this method would be a useful tool for the international agricultural research centers of the Consultative Group for International Agricultural Research (CGIAR), streamlining business processes, strengthening accountability, sharpening the research agenda it supports, fostering broader partnerships, and increasing the relevance and impact of CGIAR research in achieving international development goals. Currently international law requires only Environmental Impact Assessments (EIAs) of specific biotechnology projects. The incorporation of environmental considerations only at the level of specific projects precludes the adoption of alternative environmental policies. In this review, we outline an SEA approach currently being considered at the International Food Policy Research Institute (IFPRI) for use in evaluating biotechnology policies. SEA may be a useful tool to inform the evaluation of biotechnology policies and priorities by taking account of information on the economic, social, and environmental benefits, cost and risks of adopting those policies." Authors' AbstractRisk, Strategic Environmental Assessment, Genetically modified organisms, Living modified organisms,

    English article usage as a window on the meanings of same, identical and similar

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    We propose an explanation for a traditional puzzle in English linguistics involving the use of articles with the nominal modifiers same, identical and similar. Same can only take the definite article the, whereas identical and similar take either the or a. We argue that there is a fundamental difference in the manner in which a comparison is made with these modifiers. Identical and similar involve direct comparisons between at least two entities and an assertion of either full property matching (identical), or partial property matching (similar). The comparison with same proceeds differently: what is compared is not linguistic entities directly, but definite descriptions of these entities that can be derived through logical entailments. John and Mary live in the same house entails the house that John lives in is the (same) house that Mary lives in. There must be a pragmatic equivalence between these entailed definite descriptions, ranging from full referential equivalence to a possibly quite minimal overlap in semantic and real-world properties shared by distinct referents. These differences in meaning and article cooccurrence reveal the sensitivity of syntax to semantic and pragmatic properties, without which all and only the grammatical sentences of a language cannot be predicted

    Strategic environmental assessment: assessing the environmental impact of biotechnology

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    Poverty reduction, Agricultural research, Environmental protection, Genetically modified organisms, Crops, Agricultural biotechnology Research, Investments, Strategic Environmental Assessment,

    Food Security in Crop, Livestock and Mixed Farming Systems in Mali

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    This study evaluates the food security status, its determinants and the coping strategies in crop, livestock and mixed crop-livestock systems in southern Mali. Interviews were conducted with 258 households that were categorized into the three farming systems based on the revenue from livestock and crop production. A linear mixed model was used to analyse the effects of household characteristics on food security using the food consumption score (FCS), household dietary diversity score (HDDS), a modified household food insecurity access scale (mHFIAS) and coping strategies as indicators. Food consumption score was significantly influenced by the farming system with highest FCS for the livestock system (88) followed by the mixed system (77) and the crop system (69). Moreover, FCS was positively influenced by the number of crops cultivated, total farm milk production, off-farm income and number of raised chickens (p \u3c 0.1). The main difference in food intake between systems was for milk with average daily consumption of 201 ml, 110 ml and 60 ml in the livestock, mixed and crop systems, respectively. HDDS was also significantly influenced by the farming system with highest HDDS values for the livestock system (8.9), followed by the mixed system (8.2) and the crop system (8.0). Further, HDDS was positively influenced by crop diversity and number of chickens, and negatively influenced by the number of family dependents. During the food shortage period of August, households from the crop system were more food insecure than households from the mixed and livestock systems with mHFIAS values of 0.9, 1.5 and 4.3, respectively. Livestock and mixed systems were more resilient to food insecurity situations than the crop system. This study confirms the direct effect of milk production on milk consumption and the importance of livestock for enhancing food security and livelihood resilience

    Using the atmospheric CO2 growth rate to constrain the CO2 flux from land use and land cover change since 1900

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    We explore the ability of the atmospheric CO2 record since 1900 to constrain the source of CO2 from land use and land cover change (hereafter “land use”), taking account of uncertainties in other terms in the global carbon budget. We find that the atmospheric constraint favors land use CO2 flux estimates with lower decadal variability and can identify potentially erroneous features, such as emission peaks around 1960 and after 2000, in some published estimates. Furthermore, we resolve an offset in the global carbon budget that is most plausibly attributed to the land use flux. This correction shifts the mean land use flux since 1900 across 20 published estimates down by 0.35 PgC year−1 to 1.04 ± 0.57 PgC year−1, which is within the range but at the low end of these estimates. We show that the atmospheric CO2 record can provide insights into the time history of the land use flux that may reduce uncertainty in this term and improve current understanding and projections of the global carbon cycle. © 2022 The Authors. Global Change Biology published by John Wiley Sons Ltd

    Single-valley high-mobility (110) AlAs quantum wells with anisotropic mass

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    We studied a doping series of (110)-oriented AlAs quantum wells (QWs) and observed transport evidence of single anisotropic-mass valley occupancy for the electrons in a 150 \AA wide QW. Our calculations of strain and quantum confinement for these samples predict single anisotropic-mass valley occupancy for well widths WW greater than 53 \AA. Below this, double-valley occupation is predicted such that the longitudinal mass axes are collinear. We observed mobility anisotropy in the electronic transport along the crystallographic directions in the ratio of 2.8, attributed to the mass anisotropy as well as anisotropic scattering of the electrons in the X-valley of AlAs
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