8,585 research outputs found
Strategies for Optimize Off-Lattice Aggregate Simulations
We review some computer algorithms for the simulation of off-lattice clusters
grown from a seed, with emphasis on the diffusion-limited aggregation,
ballistic aggregation and Eden models. Only those methods which can be
immediately extended to distinct off-lattice aggregation processes are
discussed. The computer efficiencies of the distinct algorithms are compared.Comment: 6 pages, 7 figures and 3 tables; published at Brazilian Journal of
Physics 38, march, 2008 (http://www.sbfisica.org.br/bjp/files/v38_81.pdf
Effects of a large irrigation reservoir on aquatic and riparian plants: a history of survival and loss
Dammed rivers have unnatural stream flows, disrupted sediment dynamics, and rearranged
geomorphologic settings. Consequently, fluvial biota experiences disturbed functioning in the novel
ecosystems. The case study is the large irrigation reservoir Alqueva in Guadiana River, Southern Iberia.
The study area was divided into three zones: upstream and downstream of the dam and reservoir.
For each zone, species composition and land use and land cover (LULC) were compared before
and after the Alqueva Dam implementation. Data consist of aquatic and riparian flora composition
obtained from 46 surveys and the area (%) of 12 classes of LULC obtained in 90 riverine sampling
units through the analysis of historical and contemporary imagery. There was an overall decrease
of several endemic species and on the riparian shrublands and aquatic stands, although di erences
in the proportion of functional groups were not significant. Nevertheless, compositional diversity
shows a significant decline in the upstream zone while landscape diversity shows an accentuated
reduction in the reservoir area and downstream of the dam, which is likely related to the loss of
the rocky habitats of the ‘old’ Guadiana River and the homogenization of the riverscape due to the
irrigation intensification. The mitigation of these critical changes should be site-specific and should
rely on the knowledge of the interactions between surrounding lands, ecological, biogeomorphologic,
and hydrological components of the fluvial ecosystemsinfo:eu-repo/semantics/publishedVersio
Multiscale model for the effects of adaptive immunity suppression on the viral therapy of cancer
Oncolytic virotherapy - the use of viruses that specifically kill tumor cells
- is an innovative and highly promising route for treating cancer. However, its
therapeutic outcomes are mainly impaired by the host immune response to the
viral infection. In the present work, we propose a multiscale mathematical
model to study how the immune response interferes with the viral oncolytic
activity. The model assumes that cytotoxic T cells can induce apoptosis in
infected cancer cells and that free viruses can be inactivated by neutralizing
antibodies or cleared at a constant rate by the innate immune response. Our
simulations suggest that reprogramming the immune microenvironment in tumors
could substantially enhance the oncolytic virotherapy in immune-competent
hosts. Viable routes to such reprogramming are either in situ virus-mediated
impairing of CD T cells motility or blockade of B and T lymphocytes
recruitment. Our theoretical results can shed light on the design of viral
vectors or new protocols with neat potential impacts on the clinical practice.Comment: 14 pages, 4 figure
An SDRAM test education package that embeds the factory equipment into the e-learning server
SDRAM (Synchronous Dynamic Random Access Memory) demand has grown exponentially since the 1980s, as a result of technological factors and new areas of application, particularly concerning communication and consumer electronics. The SDRAM market represented in 2007 c. 20% of the total semiconductor business and is seen as a strategic area, justifying private and public investment in the western and far-eastern economic communities. SDRAM test education is therefore an important subject, but very high purchase and maintenance costs keep test equipment beyond reach of most university test courses. This paper presents a pilot project addressing an SDRAM test education course developed jointly by Qimonda and the University of Porto (FEUP), where the company offers remote access to one if its Advantest SDRAM automatic test equipments. Access to this remote tester was embedded into the Moodle e-learning server that supports a new course entitled Electronic Systems Testing (TSEL), which is part of the Integrated Masters degree on Electrical and Computer Engineering at FEUP. The excellent feedback received from students encouraged us to extend this cooperation into an educational network, which is also introduced in this paper
O potencial da grevÃlea (Grevillea robusta A. Cunn.) para reflorestamento.
Seminário realizado em Curitiba, de 6 a 8 de outubro de 1998
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