673 research outputs found
Pressure probe compensates for dimensional tolerance variations
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
How to make agricultural extension demand-driven?: The case of India's agricultural extension policy
"Many countries have recognized the need to revive agricultural advisory or extension services (the terms are used interchangeably here) as a means of using agriculture as an engine of pro-poor growth; reaching marginalized, poor, and female farmers; and addressing new challenges, such as environmental degradation and climate change. In spite of ample experience with extension reform worldwide, identifying the reform options most likely to make extension more demand-driven remains a major challenge. The concept of demand-driven services implies making extension more responsive to the needs of all farmers, including women and those who are poor and marginalized. It also implies making extension more accountable to farmers and, as a consequence, more effective. This essay discusses various options for providing and financing agricultural advisory services, which involve the public and private sectors as well as a third sector comprising nongovernmental organizations and farmer-based organizations. We review the market and state failures, and the âcommunityâ failures (failures of non-governmental and farmer-based organizations) inherent in existing models of providing and financing agricultural extension services and then outline strategies to address those failures and make extension demand-driven. Then we examine India's Policy Framework for Agricultural Extension, which has demand-driven extension as one of its major objectives, and review available survey information on the state of extension in India. We conclude that although the framework proposes a wide range of strategies to make agricultural extension demand-driven, it is less specific in addressing the challenges inherent in those strategies. Moreover, it remains unclear whether the strategies proposed in the framework will be able to address one of the major problems identified by farm household surveys: access to agricultural extension." from Authors' AbstractDemand-driven agricultural advisory services, Extension reform, Agricultural extension work, Agricultural policy, Pro-poor growth, Farmers, Environmental degradation, Climate change, Public-private sector cooperation, Non-governmental organizations,
Development of a relatchable cover mechanism for a cryogenic IR-sensor
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
Promises and realities of community-based agricultural extension
In view of the market failures and the state failures inherent in providing agricultural extension, community-based approaches, which involve farmersâ groups, have gained increasing importance in recent years as a third way to provide this service. The paper discusses the conceptual underpinnings of community-based extension approaches, highlights theoretical and practical challenges inherent in their design, and assesses the evidence available so far on their performance. The paper reviews both quantitative and qualitative studies, focusing on three examples that contain important elements of community-based extension: the National Agricultural Advisory Services program of Uganda, the agricultural technology management agency model of India, and the farmer field school approach. The review finds that in the rather few cases where performance has been relatively carefully studied, elite capture was identified as a major constraint. Other challenges that empirical studies found include a limited availability of competent service providers, deep-seated cultural attitudes that prevent an effective empowerment of farmers, and difficulties in implementing farmersâ control of service providersâ contracts. The paper concludes that, just as for the state and the market, communities can also fail in extension delivery. Hence, the challenge for innovative approaches in agricultural extension is to identify systems that use the potential of the state, the market, and communities to create checks and balances to overcome the failures inherent in all of them.agricultural extension, Agricultural technology, community-based development, empowerment of farmers, innovative approaches, market failures, National Agricultural Advisory Services program,
Negative quantum capacitance in graphene nanoribbons with lateral gates
We present numerical simulations of the capacitive coupling between graphene
nanoribbons of various widths and gate electrodes in different configurations.
We compare the influence of lateral metallic or graphene side gate structures
on the overall back gate capacitive coupling. Most interestingly, we find a
complex interplay between quantum capacitance effects in the graphene
nanoribbon and the lateral graphene side gates, giving rise to an
unconventional negative quantum capacitance. The emerging non-linear capacitive
couplings are investigated in detail. The experimentally relevant relative
lever arm, the ratio between the coupling of the different gate structures, is
discussed.Comment: 8 pages, 6 figure
Decentralization Policy and The Struggle for Authority Over Forest Resources in Tebo Regency, Jambi
Kebijakan desentralisasi atau yang umum dikenal dengan istilah otonomi daerah mengamanatkan kepada pusat untuk menyerahkan berbagai kewenangan pemerintahan kepadadaerah. Penyerahan kewenangan kepada daerah ini dimaksudkan agar tata pemerintahan dan pelayanan publik dapat berjalan secara lebih efektif dan efisien. Namun, peralihan sistem pemerintahan dari sentralisasi ke desentralisasi tidak selamanya berjalan lurus mulus. Ketegangan hubungan pusat dan daerah terjadi akibat keengganan penyelenggara pemerintahan di tingkat pusatmenyerahkan kewenangan kepada daerah dan egoisme kedaerahan yang berlebihan ditandai dengan terbitnya berbagai Peraturan Daerah yang bertentangan dengan peraturan di atasnya. Hal ini mengakibatkan ketidakpastian hukum yang berpotensi memicu konflik antara pusat dan daerah serta antara kelompok masyarakat menyangkut hak mereka untuk mendapatkan manfaat, akses dan tanggung jawab atas sumber daya alam termasuk huta
Food Security in Crop, Livestock and Mixed Farming Systems in Mali
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
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 âland useâ), 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 yearâ1 to 1.04 ± 0.57 PgC yearâ1, 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
The dichotomy between state- and market-oriented agricultural development narratives: Beyond the rational choice explanation?
While there is renewed interest to promote agricultural development, there is a lively policy debate on the appropriate instruments to achieve this goal. While some actors argue that agricultural development requires strong government support and input subsidies, others criticize those state-focused instruments and favor market-oriented approaches. This paper aimed at contributing to a better understanding of the prevailing policy narratives in the agricultural policy making landscape, using Senegal as a case study example. Transcripts of in-depth interviews conducted with policy stakeholders in Senegal are the primary data source. The empirical analysis reveals that, there are two main coalitions with opposing policy narratives; âagricultural supportâ narrative coalition and âagricultural support critiqueâ narrative coalition. The story-line of the agricultural support critique emphasizes that, the government provision of input subsidies is ineffective while story-line of the proponents of such policies consider support essential to promote agricultural development. The analysis of the narratives suggests that, the agricultural support coalition has a story-line with a beginning (low productivity caused by lack of inputs), middle (providing subsidized inputs) and end (increased productivity). In contrast, the agricultural support critique essentially presents ânon-storiesâ and âcounter storiesâ (focusing on alternative storyline of what should not be done)
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