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Shifting perceptions of food security and land in the context of labour out-migration in rural Nepal 总被引:1,自引:0,他引:1
This paper presents the results of a survey of the livelihoods of people living in the eastern part of the subtropical plains of Nepal, known as the terai. Both qualitative and quantitative approaches were used in the survey and further data were obtained through focus group discussions, in-depth interviews with key informants and participant observations. Changes were recorded both in the perception of agricultural and residential land for a secure living and the meaning given to food security. The principal drivers causing these changes were voluntary out-migration for remunerative employment, urbanization and the reluctance of members of the younger generation to farm, which they regard as a “dirty job”. In consequence, people’s livelihood practices and access to food are gradually shifting from an agriculture-based economy to an economy that is based on other sources of income, including remittances from out-migrants. This development threatens not only the role of agriculture in rural livelihoods but also the food security of the country. 相似文献
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Alexandra L. Carabat Sybrand van der Zwaag Willem G. Sloof 《Journal of the American Ceramic Society》2015,98(8):2609-2616
Alumina encapsulated molybdenum silicide (MoSi2) intermetallic particles were synthesized using a simple precipitation method followed by calcining at temperatures of 800°C–1000°C, to prevent the premature oxidation of MoSi2 at high temperatures. The shell composition and the influence of the calcining temperature on microcapsule integrity were investigated by means of X‐ray photoelectron spectroscopy, X‐ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The results demonstrate that the composition and the mechanical stability of the alumina shell can be tuned by the annealing temperature. After calcining at 800°C and 850°C the alumina shell remains intact. Calcining at higher temperature promotes the formation of mullite, which leads to cracking of the shell. However, when annealed at 1000°C for 24 h these cracks were filled with mullite and preserved the molybdenum silicide particles. Furthermore, the mechanical stability of the shell was improved by applying an intermediate calcining treatment at 450°C prior to the annealing process at 1000°C. 相似文献
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Willem‐Jan A. de Wijs Jozua Laven Gijsbertus de With 《American Institute of Chemical Engineers》2016,62(12):4453-4465
It is shown that complications in currently used optical measurements for wetting and flow resistance over edges can be circumvented by surface tension force measurements. These forces are measured by employing a modified Wilhelmy plate testing technique in which a plate with rectangular holes is immersed. The forces measured during immersion and emersion are subdivided into mass, buoyancy, and surface tension related parts, where the flow resistance when the meniscus passes horizontal faces and edges of the plate receives particular attention. Combining this experimental method with wetting theory, we show that we can predict and measure the full force curve for meniscus shape transitions over edge geometries under quasi‐static conditions. Moreover, wetting effects directly linked to surface defects can be detected qualitatively. We also point to the speed‐dependent rupture of metastable films formed during emersion. The measurement method designed is most relevant in cases where optical methods cannot be used. © 2016 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 62: 4453–4465, 2016 相似文献
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P. Visser Y. Liu H. Terryn J. M. C. Mol 《Journal of Coatings Technology and Research》2016,13(4):557-566
Lithium salts are being investigated as leachable corrosion inhibitor and potential replacement for hexavalent chromium in organic coatings. Model coatings loaded with lithium carbonate or lithium oxalate demonstrated active corrosion inhibition and the formation of a protective layer in a damaged area during neutral salt spray exposure. The present paper provides an abridged overview of the initial studies into this novel inhibitor technology for the active corrosion protection of aluminum alloys. Coating defects were investigated by microscopic techniques before and after exposure to corrosive conditions. Scanning electron microscopy analysis of cross-sections of the coating defect area demonstrated that the protective layer comprises a typical three-layered structure, which included a dense layer near the alloy surface, a porous middle layer, and a flake-shaped out layer. Potentiodynamic polarization measurements obtained with a microcapillary cell positioned in the coating defect area and electrochemical impedance spectroscopy confirmed the corrosion protective properties of these protective layers. The long-term corrosion inhibition of the lithium-based coating technology was tested in industrial coating systems. 相似文献
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Anastasia S. Domazou Janusz M. Gebicki Thomas Nauser Willem H. Koppenol 《Israel journal of chemistry》2014,54(3):254-264
In vivo, proteins are the main targets for radicals and other reactive species. Their reactions result in formation of amino acid radicals on the protein surface that often yield tryptophan and tyrosyl radicals or, in the presence of O2, protein peroxyl radicals and hydroperoxides. All these species may propagate damage to biomolecules. Low molecular weight antioxidants, such as ascorbate, urate, and glutathione, are part of the defense system and function by repairing damaged proteins. We briefly review the existing knowledge about protein and amino acid radicals and their repair by antioxidants, including results of our investigations. The main question addressed is whether the antioxidants ascorbate, urate, and glutathione are able to repair amino acid radicals in model compounds and in proteins in vitro by pulse radiolysis. We show that ascorbate and urate repair tryptophan and tyrosyl radicals efficiently and inhibit proton-coupled electron transfer from tyrosine residues to tryptophan radicals in a number of proteins. In contrast, repair by glutathione is much slower. Ascorbate also rapidly reduces the peroxyl radicals of the N-acetylamide derivatives of glycine, alanine, and proline, whereas glutathione reduces peroxyl radicals in lysozyme. In vivo urate, ascorbate, and glutathione may prevent biological damage or, at least, reduce its rate, because they: (a) repair tryptophan and tyrosyl radicals in proteins and (b) reduce protein peroxyl radicals to the corresponding protein hydroperoxides. Most likely, in vivo, ascorbate and glutathione do not inhibit the reaction of C-centered amino acid radicals with O2. Glutathione is less efficient that urate and ascorbate in repairing protein radicals; furthermore, the resulting glutathiyl radical is harmful. Ascorbate may be the more important repair agent in cells and tissues characterized by high ascorbate concentrations, such as the lens and brain; urate may be mainly responsible for repair in tissue compartments with higher urate concentrations, such as in plasma and saliva. 相似文献
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The research facility DESDEMONA features a unique motion platform, combining a fully gimbaled cabin with the capability of
producing sustained g-loads. Originally designed for ground-based simulation as well as training of spatial disorientation
in aviation, the motion capabilities are also interesting for other areas. In this paper we will provide examples of space-related
research questions that can be addressed on DESDEMONA. Some questions are concerned with centrifugation as a means to create
artificial gravity. For instance, with its variable radius and gimbaled cabin, DESDEMONA allows for studying possible trade-offs
between g-load and angular velocity. Other questions relate to the effects of g-level transitions on the astronauts’ well-being
and performance. During the last two decades, research at TNO has shown that after prolonged exposure to centrifugation at
3 g astronauts experience the same vestibular adaptation symptoms as observed in real space flight. In DESDEMONA, the hyper-gravity
stimulus can be applied and the consequences for control of simulated spacecraft can be examined in the same device. Furthermore,
DESDEMONA also provides a ‘clinical’ tool for vestibular examination of astronauts, and for the provocation and desensitization
of motion sickness in unusual G-environments. 相似文献