26,858 research outputs found
The mechanism for the electrooxidation of procarbazine pharmaceutical preparation in alkaline media and its mathematical description
The mechanism for the electrooxidation of procarbazine in alkaline media has been proposed. The process is realized completely on the electrode surface and is adsorption-controlled. The oscillatory behavior in this case is more probable, than for neutral media and may be caused by influences of electrochemical oxidation and salt dissolution from the electrode surface
Estimativa do custo de produção de café agroecológico no Município de Alto Paraíso - Rondônia.
Considerando a necessidade de se gerar informações socioeconômicas que contribuam para o delineamento de agroecossistemas sustentáveis, objetivo deste trabalho é a determinação do custo de produção do café robusta em sistema agroecológico no Município de Alto Paraíso, Rondônia. Pretende-se ainda determinar a renda auferida por uma unidade de produção típica do sistema café-mel-madeira.bitstream/item/24715/1/cot317-cafeagroecologico.pd
Mapping the train model for earthquakes onto the stochastic sandpile model
We perform a computational study of a variant of the ``train'' model for
earthquakes [PRA 46, 6288 (1992)], where we assume a static friction that is a
stochastic function of position rather than being velocity dependent. The model
consists of an array of blocks coupled by springs, with the forces between
neighbouring blocks balanced by static friction. We calculate the probability,
P(s), of the occurrence of avalanches with a size s or greater, finding that
our results are consistent with the phenomenology and also with previous models
which exhibit a power law over a wide range. We show that the train model may
be mapped onto a stochastic sandpile model and study a variant of the latter
for non-spherical grains. We show that, in this case, the model has critical
behaviour only for grains with large aspect ratio, as was already shown in
experiments with real ricepiles. We also demonstrate a way to introduce
randomness in a physically motivated manner into the model.Comment: 14 pages and 6 figures. Accepted in European Physical Journal
Demonstration of new possibilities of multilayer technology on resistive microstrip/ microdot detectors
The first successful attempts to optimize the electric field in Resistive
Microstrip Gas Chamber and resistive microdot detectors using additional field
shaping strips located inside the detector substrate are describedComment: Presented at the RD-51 mmini week, CERN, June 201
Simulations of a mortality plateau in the sexual Penna model for biological ageing
The Penna model is a strategy to simulate the genetic dynamics of
age-structured populations, in which the individuals genomes are represented by
bit-strings. It provides a simple metaphor for the evolutionary process in
terms of the mutation accumulation theory. In its original version, an
individual dies due to inherited diseases when its current number of
accumulated mutations, n, reaches a threshold value, T. Since the number of
accumulated diseases increases with age, the probability to die is zero for
very young ages (n = T). Here, instead
of using a step function to determine the genetic death age, we test several
other functions that may or may not slightly increase the death probability at
young ages (n < T), but that decreases this probability at old ones. Our
purpose is to study the oldest old effect, that is, a plateau in the mortality
curves at advanced ages. Imposing certain conditions, it has been possible to
obtain a clear plateau using the Penna model. However, a more realistic one
appears when a modified version, that keeps the population size fixed without
fluctuations, is used. We also find a relation between the birth rate, the
age-structure of the population and the death probability.Comment: submitted to Phys. Rev.
Fast screening methodology for the assessment of cassava resistance to the passalora disease complex.
Among the several pathogens of cassava (Manihot esculenta Crantz), the Passalora spp. complex is by far the most frequent worldwide. Three different diseases make up this complex: blight leaf spot (BILS) caused by P. vicosase, brown leaf spot (BLS) caused by P. henningsii and white leaf spot (WLS) caused by P. manihotis
- …