Entropy generation in a model of reversible computation

We present a model in which, due to the quantum nature of the signals controlling the implementation time of successive unitary computational steps, \emph{physical} irreversibility appears in the execution of a \emph{logically} reversible computation.Comment: 13 pages, 6 figure

Diversification as a Form of Risk Management in Agriculture

The objective of this study is to show the importance of diversification in the risk management process. The study areas are: Mato Grosso, with large properties, and Rio Grande do Sul with small. The developed activities are annual cultures and cattle for slaughter. The hypotheses of the work are: a) rural producers diversify their activities using modern techniques. b) Diversification has been efficient in the producers' risks reduction. c) Producers tend be as effective as possible, though they differ in the rates of risk aversion. The MOTAD and E-V models were used.Farm Management,

Second Comment on "Contextuality within quantum mechanics manifested in subensemble mean values" [Phys. Lett. A 373 (2009) 3430]

I examine Pan and Home's reply to my Comment on their proposal for testing noncontextual models. I show that the Kochen-Specker model for a qubit does explain all outcomes of a test based on such a proposal, so that it would be inconclusive about the untenability of realistic, noncontextual models.Comment: 5 pages, no figures

Observing the evolution of a quantum system that does not evolve

This article deals with the problem of gathering information on the time evolution of a single metastable quantum system whose evolution is impeded by the quantum Zeno effect. It has been found it is in principle possible to obtain some information on the time evolution and, depending on the specific system, even to measure its average decay rate, even if the system does not undergo any evolution at all.Comment: Two over three PRA referees didn't like the old title... And no more quantum circuits in the new versio

Juvenile Parkinson disease caused by parkin mutations: large deletions and pathogenic mechanisms

Dissertação para obtenção do Grau de Mestre em Genética Molecular e BiomedicinaAutosomal recessive juvenile Parkinson disease (AR-JP) is mainly caused by mutations in PARK2. AR-JP presents with rigidity, bradykinesia and resting tremor, usually before age 40 years. Large PARK2 deletions account for 50% of the mutations identified in patients with AR-JP of Portuguese origin. The PARK2 gene encodes parkin, an E3 ubiquitin ligase, an important part of the cellular machinery that covalently tags target proteins with ubiquitin for degradation by the ubiquitinproteasome system (UPS), the main cellular protein degradation system responsible for targeted degradation of damaged and misfolded proteins. This project aims were: determine the breakpoints of the deletion found in Portuguese patients in order to identify the genomic mechanisms underlying these gene rearrangements and to explore the pathogenic mechanisms of parkin mutations by assessing the dynamics of formation and degradation of aggregates by UPS and also by determining its effects in the UPS degradation capacity and its relation with neuronal death. A successful approach was developed to narrow the deletion breakpoint intronic position. Cellular models expressing wild-type and mutant parkin were developed and characterized regarding mRNA and protein expression, as well as, aggregate formation, cell viability and proteasome activity. Our data show that the different studied mutations do not have an impact on cell viability, although resulted in differences in the number of cell with aggregates for the cells expressing N52MfsX29, L358RfsX77 and R275W mutants as well as in the number of aggregates present in each cell. We were also able to show that proteasome inhibition has as impact both in cell viability and in aggregate formation, resulting in decreased viability and increased aggregate formation. The study of the cellular mechanisms resulting in neuronal dysfunction is crucial for the identification of potential therapeutic targets for Parkinson disease

Experimental test of the no signaling theorem

In 1981 N. Herbert proposed a gedanken experiment in order to achieve by the ''First Laser Amplified Superluminal Hookup'' (FLASH) a faster than light communication (FTL) by quantum nonlocality. The present work reports the first experimental realization of that proposal by the optical parametric amplification of a single photon belonging to an entangled EPR pair into an output field involving 5 x 10^3 photons. A thorough theoretical and experimental analysis explains in general and conclusive terms the precise reasons for the failure of the FLASH program as well as of any similar FTL proposals.Comment: 4 pages, 4 figure

Neutrino Decay and Solar Neutrino Seasonal Effect

We consider the possibility of solar neutrino decay as a sub-leading effect on their propagation between production and detection. Using current oscillation data, we set a new lower bound to the $\nu_2$ neutrino lifetime at $\tau_2\, /\, m_2 \geq 7.2 \times 10^{-4}\,\,\hbox{s}\,.\,\hbox{eV}^{-1}$ at $99\%\,$C.L.. Also, we show how seasonal variations in the solar neutrino data can give interesting additional information about neutrino lifetime

Counseling Brazilian Farmers on Their Management Activities

The study identified some reasons that explain the limited use of scientific management tools by Brazilian farmers. A matrix of management activities was built to classify these reasons. Primary data used in the study were collected during two phases. During the first, 8 focus group manned by cash crop farmers, beef cattle farmers, and extension agents and counselors, were used to produce qualitative information. During the second phase, quantitative informations were collected via a survey with 494individual questionnaires applied to the same public covered by phase one. For the statistical tests performed 95% of significance was required. Some conclusions of the study are: (1) farmers differ significantly from extension agents or counselors on farm management subjects; (2) farmers do not alter their strategic production plans in response to price changes or other signals perceived as short or mid term movements due to costs of changes in their production processes; (3) in organizing their human resources structure farms tend to concentrate into their hands amounts of responsibilities larger than they can handle; (4) in organizing their financial flows there is a large gap between the desired level of details and their abilities to collect the data; and (5) the major difficulties faced in the function of controlling are linked with problems of collecting data. This is due to low levels of formal education that characterize the farm-hired labor.Brazilian farm management, counseling farmers, matrix of management activities., Farm Management, Teaching/Communication/Extension/Profession,