2,549 research outputs found
Why some fields might be rectangular: an exploration of agricultural landscapes between pre-capitalist and capitalist modes of production
This article is a preliminary investigation of possible spatial form which starts by rejecting the idea that spatial theory can be built from assumptions of isomorphism. It examines spatial form in high potential ridge valley areas which are densely populated, and identifies the transition in land configuration for pre-capitalist to capitalist modes of production. In building the argument simple geometric patterns that differentiate from the model are postulated. The basic drivers of the differing spatial systems are essentially the superstructural legal conditions which are postulated as a moving from communal, customary law to individual statutory property rights
Gakarara: A Study in the Development of Underdevelopment.
This thesis arises out of a microscopic examination of an agricultural community in Kenya. It examines the ecological situation in one village, Gakarara, and then attempts to discuss aspects of subsistence living within this ecological framework. The population dynamics of this underdeveloped community are examined and the urban linkages, that drain the people away from the village, emerge as critical variables in the village economy. Political and social elements of village life are discussed and the bureaucratic nature of the development administration is emphasised. An examination of landuse and farm output highlight the fact that the area is turning back from a cash crop economy into a subsistence economy. The nutritional study indicates that the community is physically vulnerable; the increasing soil erosion, through lack of labour for terracing, suggests that the community is in a situation which is rapidly deteriorating. The whole process is seen not as one of modernization but as negative development, or the development of underdevelopment
On certain regular graphs of girth 5
Let f(v,5) be the number of vertices of a (v,5)-cage (vâ„3). We give an upper bound for f(v,5) which is considerably better than the previously known upper bounds. In particular, when v=7, it coincides with the well-known Hoffman- Singleton graph
Blue harvest: inland fisheries as an ecosystem service
Global food production has increased greatly in recent years and rural livelihoods are much improved in many regions. Yet, despite this clear progress rural poverty and food insecurity remain deeply entrenched in many areas, especially in South Asia and sub-Saharan Africa. In response the international community has renewed calls for increased commitment to meeting the needs of the world's poor. This report, commissioned as a contribution to the 10th Conference of the Parties to the Convention on Biological Diversity taking place in Nagoya, Japan, not only underlines the value of freshwater fisheries but provides guidance on how the ecosystem approach can be applied in order to sustain future harvests.Inland fisheries, Nutrition, Food security, Sustainability, Ecosystems
Rice endosperm is cost-effective for the production of recombinant griffithsin with potent activity against HIV
Protein microbicides containing neutralizing antibodies and antiviral lectins may help to reduce the rate of infection with human immunodeficiency virus (HIV) if it is possible to manufacture the components in large quantities at a cost affordable in HIVâendemic regions such as subâSaharan Africa. We expressed the antiviral lectin griffithsin (GRFT), which shows potent neutralizing activity against HIV, in the endosperm of transgenic rice plants (Oryza sativa), to determine whether rice can be used to produce inexpensive GRFT as a microbicide ingredient. The yield of (OS)GRFT in the bestâperforming plants was 223Â ÎŒg/g dry seed weight. We also established a oneâstep purification protocol, achieving a recovery of 74% and a purity of 80%, which potentially could be developed into a largerâscale process to facilitate inexpensive downstream processing. (OS)GRFT bound to HIV glycans with similar efficiency to GRFT produced in Escherichia coli. Wholeâcell assays using purified (OS)GRFT and infectivity assays using crude extracts of transgenic rice endosperm confirmed that both crude and pure (OS)GRFT showed potent activity against HIV and the crude extracts were not toxic towards human cell lines, suggesting they could be administered as a microbicide with only minimal processing. A freedomâtoâoperate analysis confirmed that GRFT produced in rice is suitable for commercial development, and an economic evaluation suggested that 1.8Â kg/ha of pure GRFT could be produced from rice seeds. Our data therefore indicate that rice could be developed as an inexpensive production platform for GRFT as a microbicide component
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Thermal Stress and Reliability for Advanced Power Electronics and Electric Machines
This presentation gives an overview of NREL's Thermal Stress and Reliability Project work from October 2007 to March 2009 with an emphasis on activity during 2008/2009
Acoustic Emission from crumpling paper
From magnetic systems to the crust of the earth, many physical systems that
exibit a multiplicty of metastable states emit pulses with a broad power law
distribution in energy. Digital audio recordings reveal that paper being
crumpled, a system that can be easily held in hand, is such a system. Crumpling
paper both using the traditional hand method and a novel cylindrical geometry
uncovered a power law distribution of pulse energies spanning at least two
decades: (exponent 1.3 - 1.6) Crumpling initally flat sheets into a compact
ball (strong crumpling), we found little or no evidence that the energy
distribution varied systematically over time or the size of the sheet. When we
applied repetitive small deformations (weak crumpling) to sheets which had been
previously folded along a regular grid, we found no systematic dependence on
the grid spacing. Our results suggest that the pulse energy depends only weakly
on the size of the paper regions responsible for sound production.Comment: 12 pages of text, 9 figures, submitted to Phys. Rev. E, additional
information availible at http://www.msc.cornell.edu/~houle/crumpling
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