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1.
IRRI's Training Program and Information and Knowledge Exchange Program entail collaboration and partnerships with national agricultural research systems (NARS). Both programs disseminate research results to develop collaborators and accelerate information transfer. IRRI's training program has evolved in parallel with IRRI's strategic research focus to address specialized needs of national rice scientists. Forging partnerships with NARS rice-related training programs to collaborate in national and regional in-country training activities addresses the more general training needs of national rice research systems. IRRI's information and knowledge exchange program publishes and disseminates research results to national rice scientists, maintains and makes available to rice scientists the world's largest collection of rice literature, develops and maintains rice data bases, organizes conferences and workshops to discuss research findings with NARS scientists, and is actively involved in public awareness activities. 相似文献
2.
Individuals and institutions cooperate with expectations of improved effectiveness and efficiency. In this paper, partnership in rice research is examined. We begin by identifying the underlying rationale for partnership vis-a-vis independent initiatives: that the benefits of working together exceed the corresponding costs. We argue that benefits are derived principally from shared interests and differences, while the major costs of partnership emerge from the need to negotiate roles and responsibilities and to exchange information. We then focus on IRRI's experience — its partners and the various collaborative mechanisms employed. Historically the national agricultural research systems have been IRRI's principal research partners. Of late the number and diversity of partners have grown, bringing significant challenges to IRRI's management approach and structure. Increased cooperation with rice farming communities, consumers, non-government organizations, advanced research institutions, and the private sector is anticipated. The emergence of research consortia as a partnership mechanism introduces the problem of indirect management, in which there is a separation of responsibility and accountability — both for IRRI and its partners. Several techniques to address this problem are suggested. 相似文献
3.
This paper focuses on the burgeoning application of genetic techniques in livestock agriculture, examining how these are changing livestock breeding knowledge-practices and the representation of animal life. Conventional livestock breeding relies on visual appraisal of animals and maintaining performance records, whereas genetic and genomic techniques offer the potential to assess particular aspects of animals’ genotypes. Advertising and promotional material produced by organisations involved in developing genetic techniques, and reportage and discussion of such techniques in the agricultural media, are used to examine the ways in which the production and value of living bodies in the future is being mapped out in emerging knowledge-practice networks which centre around particular visions and representations of what livestock bodies are and should do or be. The paper argues that bodies should be understood in part in terms of the wider spatial relationships in which they are entangled. A process of’circulating reference’ [Latour, B., 1999. Pandora’s Hope: Essays on the Reality of Science Studies. Harvard University Press, Cambridge, MA] is identified in which rounds of simplification occur in relation to the representation of the genetic qualities of livestock animals. However, these attempts to simplify produce new complexities when livestock breeders attempt to make use of genetic knowledge-practices. Identifying different modes of complexity, the paper discusses their spatiality in terms of differences between genetic abstractions from animal bodies and breeders ‘multi-layered ‘lay’ knowledges of their livestock animals. 相似文献
4.
This paper explores some of the key institutional transformations in livestock breeding associated with the increasing significance of genetic techniques, situating this within an assessment of an emerging agricultural bioeconomy. Focusing on beef cattle and sheep breeding in the United Kingdom, the paper examines how a move towards the involvement of international and corporate interests in livestock breeding is restructuring the network of institutional interests affecting the knowledge and decision making of individual breeders. The paper suggests that the structural transformation of beef cattle and sheep breeding is complicated by the need for negotiation between breeders’ ‘traditional’ knowledge-practices and the ‘geneticised’ techniques being made available to them. We are thus seeing the emergence of new and complex interactions between the major actors which are reconfiguring power relationships in the UK livestock breeding sector. 相似文献
5.
M. A. Arraudeau 《GeoJournal》1995,35(3):325-328
IRRI's upland rice research has made progress in solving some of the dilemmas in the upland rice ecosystem, although many challenges remain. IRRI researchers are gaining a better understanding of the ecosystem's constraints, opportunities, and research approaches. Cultivar improvement, use of farmer participatory methods to reduce erosion, and weed management are areas where research advances are being made. Developing perennial upland rice and managing weeds using less herbicide are exciting new projects being pursued. Enhancing rice productivity is seen as an entry point to alleviating the interrelated problems of declining productivity, lack of sustainability, and poverty in the uplands. Delay can irreparably damage the uplands and gravely affect the people who depend on them for survival. 相似文献
6.
Michael T. Jackson 《GeoJournal》1995,35(3):267-274
The development of improved rice varieties depends upon access to the genetic resources of rice. These are represented by the thousands of locally adapted varieties that farmers have grown for generations, and over 20 wild rice species native to Asia, Africa, and Latin America. Rice genetic resources are threatened with extinction in farming systems when farmers adopt improved varieties, and the wild species may be lost through destruction of their habitats.IRRI has been at the forefront of international efforts for three decades to collect and conserve the biodiversity of rice. More than 80,000 samples of cultivated and wild rices are conservedex situ in the genebank at IRRI.In situ conservation of rice genetic resources is likely to become an important complementary strategy in the future.Through utilization of rice germplasm, resistances to pests and diseases have been incorporated into improved varieties. These are shared worldwide through the International Network for Genetic Evaluation of Rice (INGER). The impact of biotechnology and intellectual property rights on germplasm conservation is discussed. 相似文献
7.
《Geoforum》2016
Bringing a biopolitical framework to bear on historical geographies of nature, this article traces the recent history of the American chestnut, with a focus on the pivotal time period in the early 20th century (1905–1925) during which the tree’s ecological, economic, and cultural roles changed dramatically. Once an ecologically dominant and culturally important forest tree in eastern North America, the American chestnut was rendered functionally extinct following the accidental introduction of a fungal pathogen, known as the chestnut blight, at the turn of the 20th century. Calling attention to the historical ties between nature and nation, I demonstrate how blight control, chestnut breeding, and restoration efforts were formulated in conversation with broader anxieties about the fate of the American nation in the wake of social, environmental, economic, and racial change. Through an exploration of three themes distilled from archival research—chestnut blight as national threat, fear and desire for exotic nature, and the shared histories of plant breeding and racial improvement—this paper illustrates the role that nature has played in the construction and circulation of biopolitical discourses, nationalist sensibilities, and gendered and racial logics. 相似文献
8.
Erik Tihelka 《Geology Today》2020,36(5):188-191
The majority of organisms that ever lived on the Earth, and hence the majority of evolutionary innovations, are now extinct. Only fragments of this past diversity are observable in the form of the fossil record. Biomimicry and biotechnology seek to utilize the astonishing diversity of living organism's solutions to complex biological problems as inspiration for human technology. This feature reviews the potential industrial applications of fossil-inspired technologies, an emerging area of research here referred to as ‘palaeobiotechnology’ or ‘brown biotechnology’. Examples from vertebrate, invertebrate and molecular palaeontology illustrate the diverse potential applications of extinct organisms, including the design of new materials such as bone substitutes, development of pharmaceuticals, robots and anchoring devices for submarines. Palaeobiotechnological approaches are able to both inspire modern sustainable technologies and at the same time illuminate the biology of ancient organisms. 相似文献
9.
In modeling of many geomechanics problems such as underground openings, soil-foundation structure interaction problems, and in wave propagation problems through semi-infinite soil medium the soil is represented as a region of either infinite or semi-infinite extent. Numerical modeling of such problems using conventional finite elements involves a truncation of the far field in which the infinite boundary is terminated at a finite distance. In these problems, appropriate boundary conditions are introduced to approximate the solution of the infinite or semi-infinite boundaries as closely as possible. However, the task of positioning the finite boundary in conventional finite element discretization and the definition of the boundary and its conditions is very delicate and depends on the modeller's skill and intuition. Moreover, such a choice is influenced by the size of the domain to be discretized. Consequently, the dimensions of the global matrices and the time required for solution of the problem will increase considerably and also selection of the arbitrary location of truncated boundary may lead to erroneous result. In order to over come these problems, mapped infinite elements have been developed by earlier researchers (Simoni and Schrefier, 1987). In the present work the applicability of infinite element technique is examined for different geomechanics problems. A computer program INFEMEP is developed based on the conventional finite element and mapped infinite element technique. It is then validated using selected problems such as strip footing and circular footing. CPU time taken to obtain solutions using finite element approach and infinite element approach was estimated and presented to show the capability of coupled modeling in improving the computational efficiency. Mesh configurations of different sizes were used to explore the enhancement of both computational economy and solution accuracy achieved by incorporation of infinite elements to solve elastic and elasto-plastic problems in semi-infinite/finite domain as applied to geotechnical engineering. © Rapid Science Ltd. 1998 相似文献
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《Geomechanics and Geoengineering》2013,8(2):139-150
The influence of a non-coaxial model for granular soils on shallow foundation analyses is investigated. The non-coaxial plasticity theory proposed by Rudnicki and Rice (J. Mech. Phys. Solids 1975, 23, 371–394) is integrated into a Drucker–Prager model with both perfect plasticity and strain hardening. This non-coaxial model is numerically implemented into the finite-element program ABAQUS using a substepping scheme with automatic error control. The influence of the non-coaxial model on footing settlement and bearing capacity is investigated under various loading and boundary conditions. Compared with the predictions using conventional coaxial models, the non-coaxial prediction results indicate that the settlement of a footing increases significantly when the non-coaxial component of plastic strain rate is taken into consideration, although ultimate footing bearing capacities are not affected significantly. The non-coaxial model has a different effect on footing settlements under different loading and boundary conditions. In general, the discrepancies between coaxial and non-coaxial predictions increase with increasing rotation of principal stresses of the soil mass beneath a footing. It can be concluded that if the non-coaxial component of plastic strain rate is neglected in shallow foundation problems using the finite-element method, the results tend to be non-conservative when designs are dominated by settlement of footings. 相似文献
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《矿物学报》2013,(Z1)
Because of the dispersion at the nanometer level, polymer-clay nanocomposites exhibit superior properties in comparison with pure polymer or conventional composites; this includes properties such as barrier properties , improved thermal stability and flame retardancy. The outstanding properties of polymer-clay nanocomposites are achieved at a much lower volume fraction, compared with conventional composites. Polymer-clay nanocomposites can be processed using common techniques, such as extrusion and casting, which are superior to the cumbersome techniques used for the conventional composites. Hence, polymer-clay nanocomposites have important potential commercial value. 相似文献
15.
裂隙岩体渗流概念模型研究 总被引：31，自引：4，他引：27
裂隙岩体中的渗流和传统的多孔介质渗流在机理上存在本质的差别,这种差别主要表现为裂隙岩体在各种尺度上存在的非均质性。模拟裂隙岩体渗流的主要困难在于描述这种非均质性。目前的概念模型,包括等效连续体模型、离散裂隙网络模型和混合模型使用了不同的技术来预测裂隙岩体中的渗流。这些模型基于不同的假设和概念框架,有着各自不同的优缺点。在实际应用时,应当根据研究域的具体特点和所要解决的问题的要求对其选择,此外,还讨论了单裂隙的概念模型。 相似文献
16.
The rapid expansion of the offshore wind sector, coupled with increasing demand for high rise structures, has placed renewed
demand on the driven piling market. In light of this industry growth, this paper reviews the evolution of design approaches
for calculating the shaft capacity of displacement piles installed in cohesive soils. The transition from traditional total
stress design towards effective stress methods is described. Complex stress–strain changes occur during pile installation,
equalisation and load testing and as a consequence, the selection of parameters for use in conventional earth-pressure type
effective stress approaches is not straight-forward. These problems have led to the development of empirical correlations
between shaft resistance and in situ tests, such as the cone penetration tests. However, many of these approaches are limited
because they were developed for specific geological conditions. Significant insight into pile behaviour has been obtained
from recent model pile tests, which included reliable measurements of radial effective stresses. These tests have allowed
factors such as friction fatigue and interface friction to be included explicitly in design methods. Whilst analytical methods
have been developed to investigate pile response, these techniques cannot yet fully describe the complete stress–strain history
experienced by driven piles. The use of analytical methods in examining features of pile behaviour, such as the development
of pore pressure during installation and the effects of pile end geometry on pile capacity, is discussed. 相似文献
17.
Antoinette M. Mannion 《GeoJournal》1993,31(4):347-354
Biotechnology is the manipulation of organisms to carry out specific processes. It has various applications that are relevant to many aspects of geography. At a fundamental level biotechnology is directed at manipulating energy flows, especially those in agriculture. Improved crop varieties, disease and pest control, as well as nutrient enhancement can all be achieved by biotechnology, culminating in increased agricultural productivity. There are significant environmental advantages though there are also constraints imposed by economic considerations. Mineral extraction, metal recycling and pollution abatement can also be improved by biotechnology which thus contributes to more efficient resource use and enhanced environmental quality. Food and fuel energy, notably biomass fuels, can also be so produced. The manifold implications of this technology for earth and social sciences thus require its inclusion in geographical studies. 相似文献
18.
Coastal processes and environmental hazards: the Buenos Aires (Argentina) and Venetian (Italy) littorals 总被引：1，自引：0，他引：1
Jorge Pousa Luigi Tosi Eduardo Kruse Dardo Guaraglia Maurizio Bonardi Andrea Mazzoldi Federica Rizzetto Enrique Schnack 《Environmental Geology》2007,51(8):1307-1316
The Buenos Aires (Argentina) and Venice (Italy) coastlands have experienced significant saltwater contamination of the phreatic
aquifer, coastal erosion, hydrodynamic changes and relative sea level rise processes due to natural and man-induced factors.
These factors expose coastal areas to morpho-hydro-geological hazards, such as soil desertification, frequency and degree
of flooding, littoral erosion, and the silting of river mouths and channels. Man-made interventions and actions, such as beach
mining, construction of coastal structures and exploitation of aquifers without an adequate knowledge of the hydrology setting
and an adequate management program, worsen these natural hazards. Uncontrolled human activity induces environmental damage
to the overall coastal plains. The coastal plains play an important role in the social/economic development of the two regions
based on land use, such as agriculture, horticulture, breeding, and tourism, as well as industry. Results of investigations
on saltwater contamination, sea level rise and morphological changes recently performed in these two coastal areas are presented
here. 相似文献
19.
Charles A. Whitten 《Tectonophysics》1986,130(1-4):9-21
Man's interest in the dynamics of the earth's crust goes back several centuries. Ekman recently pointed out the theory of post-glacial uplift in Fennoscandia. In the 15th century, towns along the Baltic-Sea experienced receding of the sea. In this century, Bowie had started a program for repeating surveys in seismically active regions. Wegeners' hypothesis of Continental Drift aroused the interest of scientists. In January 1985, Walter Sullivan traced the evolution from Wegener's continental drift through plate tectonics to the latest suggestion of the formation of continents from “terranes”. Spatial techniques. Laser Ranging, VLBI, GPS have given geodesists the ability to monitor continental drift, intracontinental deformations and other phenomena.
Along faults, such as the San Andreas Fault, the conventional geodetic approach to deformation has been to use a linear concept, except for episodic events such as earthquakes and so on.
Wayne Thatcher's model on the declining strain rate is justified if sufficient geodetic data, well distributed, are available. Strain components can be computed from distortion patterns which might develop when an earlier survey is adjusted to be made consistent with a later survey. There exists a correlation of the movement of the instantaneous pole of rotation with the energy release of all earthquakes. 相似文献
20.
Y. Chen E.R.M. Mariba L. Van Dyk J.H. Potgieter 《International Journal of Mineral Processing》2011,98(1-2):1-7
In recent years several kinds of gas phase methods/techniques, utilizing organic ligands, have been developed to recover metals from low grade ore or slag, for the removal of heavy metals from industrial waste, as well as solution purification. These methods include, extraction of metals in fluidized bed reactors using organic chelating compounds such as the SERVO process, and metal extraction by supercritical fluid extraction with CO2 (SFC), followed by a potential method to recycle the metal and regenerate the ligand. These methods are hydrogen reduction, electrochemical separation and acid stripping. This review looks at the extraction of metals by organic ligands, and a brief introduction to the advantages and disadvantages of these two techniques (SERVO and SFC) is presented. A comparison of metal extraction using the two techniques is presented; some conventional methods are discussed, as well as the problems they present. Selected results of the extraction of iron by a gasified ligand in a fluidized reactor are shown to illustrate the potential application and success of this approach. Kinetic models governing such gas–solid state reactions are discussed, and possible ways to recycle the ligand(s) and recover metals in their pure (reduced) state highlighted. Finally, some ideas and suggestions for improvements in the research that had been carried out to date, as well as further future developments deserving attention, are suggested in the conclusion. 相似文献