31,372 research outputs found
Overcoming ambiguities in classical and quantum correlation measures
We identify ambiguities in the available frameworks for defining quantum,
classical, and total correlations as measured by discordlike quantifiers. More
specifically, we determine situations for which either classical or quantum
correlations are not uniquely defined due to degeneracies arising from the
optimization procedure over the state space. In order to remove such
degeneracies, we introduce a general approach where correlations are
independently defined, escaping therefore from a degenerate subspace. As an
illustration, we analyze the trace-norm geometric quantum discord for two-qubit
Bell-diagonal states.Comment: 5 pages, 2 figures. v2: Minor corrections. Published versio
Marcha de absorção e acúmulo de zinco, manganês, ferro, cobre e boro em soja com tipo de crescimento indeterminado.
Marcha de absorção e acúmulo de macronutrientes em soja com tipo de crescimento indeterminado.
Principais doenças do feijoeiro comum (Phaseolus vulgaris L) no Pará: descrição de sintomas e recomendações de controle.
bitstream/item/57876/1/Belem-CirTec4.pd
Avaliação do comportamento de cultivares de feijão no município de Altamira, PA.
bitstream/item/57419/1/CPATU-ComTec64.pd
Avaliação de genótipos de feijão (Phaseolus vulgaris L.) no nordeste do Pará.
bitstream/item/57398/1/CPATU-PA173.pd
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.
Avaliação de genótipos de feijão na microrregião Bragantina, Pará.
bitstream/item/57531/1/CPATU-PA213.pd
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