17,585 research outputs found
Saberes ambientais dos trabalhadores rurais no assentamento Darcy Ribeiro: um estudo de caso.
bitstream/CPATC-2009-09/20205/1/f_07_2008.pd
Immunization and Aging: a Learning Process in the Immune Network
The immune system can be thought as a complex network of different
interacting elements. A cellular automaton, defined in shape-space, was
recently shown to exhibit self-regulation and complex behavior and is,
therefore, a good candidate to model the immune system. Using this model to
simulate a real immune system we find good agreement with recent experiments on
mice. The model exhibits the experimentally observed refractory behavior of the
immune system under multiple antigen presentations as well as loss of its
plasticity caused by aging.Comment: 4 latex pages, 3 postscript figures attached. To be published in
Physical Review Letters (Tentatively scheduled for 5th Oct. issue
Magnetic Properties of the Metamagnet Ising Model in a three-dimensional Lattice in a Random and Uniform Field
By employing the Monte Carlo technique we study the behavior of Metamagnet
Ising Model in a random field. The phase diagram is obtained by using the
algorithm of Glaubr in a cubic lattice of linear size with values ranging
from 16 to 42 and with periodic boundary conditions.Comment: 4 pages, 6 figure
Smart and sustainable cities in the Mediterranean region: The contribution of short supply chains of food
The cities around the world in general, and in the Mediterranean area in particular, are facing tremendous challenges at the environmental, social, economic, and institutional levels, due to the urbanization trend, environmental climatic changes and challenges due to the ongoing COVID-19 pandemic. Therefore, cities need to be sustainable and smart in the future. An economically important and innovative sector in urban areas is food security. Nowadays, most of the literature explores the concept of smart cities from the point of view of information and communications technology, indeed, the connection with the sustainability aspects of the food supply chain and the ways to operationalize that, remains unsolved. This paper tries to overcome this gap in the literature. The main aim is to analyze the contribution of the short supply chain of food in terms of sustainability in smart cities, regarding current urban trends in cities in general and in Mediterranean areas in particular. The methodology was based on a literature review and includes quantitative and qualitative analysis. The results confirm the existence of positive impacts in the short supply chains of food in urban areas in terms of sustainability. Despite the existence of a considerable number of papers about smart cities and ICT-related topics, the benefits from society of short supply chains of food, and the linkage among the topics and subjects, remain unreferred to or with a limited knowledge exchange. The conclusions of this paper will be helpful for public decision makers to implement policies in order to promote the sustainability of Mediterranean cities.info:eu-repo/semantics/publishedVersio
Origens, crescimento e progressos na cotonicultura do Brasil.
Origens e crescimento da cotonicultura; Progressos na cotonicultura.bitstream/item/130108/1/ORIGEM-CRESCIMENTO.pd
Phenomenological study of the electronic transport coefficients of graphene
Using a semi-classical approach and input from experiments on the
conductivity of graphene, we determine the electronic density dependence of the
electronic transport coefficients -- conductivity, thermal conductivity and
thermopower -- of doped graphene. Also the electronic density dependence of the
optical conductivity is obtained. Finally we show that the classical Hall
effect (low field) in graphene has the same form as for the independent
electron case, characterized by a parabolic dispersion, as long as the
relaxation time is proportional to the momentum.Comment: 4 pages, 1 figur
Anuário estatístico - suinocultura: central de inteligência da Embrapa Suínos e Aves.
bitstream/item/46832/1/Documento-146.pdfProjeto: 04.08.08.017
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