Electron to selectron pair conversion in a SUSY bubble

In the standard model, energy release in dense stars is severely restricted by the Pauli exclusion principle. However, if, in regions of space of high fermion degeneracy, there is a phase transition to a state of exact supersymmetry (SUSY), fermion to sfermion pair conversion followed by radiative transitions to the Bose ground state could lead to a highly collimated gamma ray burst. We calculate the cross section for electron to selectron pair conversion in a SUSY bubble and construct a monte carlo for the resulting sfermion amplification by stimulated emission.Comment: 13 pages, 4 figures, published version with "with jet production by Bose enhancement" added to titl

The shock-acoustic waves generated by earthquakes

We investigate the form and dynamics of shock-acoustic waves generated by earthquakes. We use the method for detecting and locating the sources of ionospheric impulsive disturbances, based on using data from a global network of receivers of the GPS navigation system and requiring no a priori information about the place and time of associated effects. The practical implementation of the method is illustrated by a case study of earthquake effects in Turkey (August 17, and November 12, 1999), in Southern Sumatera (June 4, 2000), and off the coast of Central America (January 13, 2001). It was found that in all instances the time period of the ionospheric response is 180-390 s, and the amplitude exceeds by a factor of two as a minimum the standard deviation of background fluctuations in total electron content in this range of periods under quiet and moderate geomagnetic conditions. The elevation of the wave vector varies through a range of 20-44 degree, and the phase velocity (1100-1300 m/s) approaches the sound velocity at the heights of the ionospheric F-region maximum. The calculated (by neglecting refraction corrections) location of the source roughly corresponds to the earthquake epicenter. Our data are consistent with the present views that shock-acoustic waves are caused by a piston-like movement of the Earth surface in the zone of an earthquake epicenter.Comment: EmTeX-386, 30 pages, 4 figures, 3 tabl

Nuclear Physics in a Susy Universe

We refine a previous zeroth order analysis of the nuclear properties of a supersymmetric (susy) universe with standard model particle content plus degenerate susy partners. No assumptions are made concerning the Higgs structure except we assume that the degenerate fermion/sfermion masses are non-zero. This alternate universe has been dubbed Susyria and it has been proposed that such a world may exist with zero vacuum energy in the string landscape.Comment: 8 pages, 1 figur

Structural and Functional Dependence of Objects in Data Bases

Let the information of a civil engineering application be decomposed into objects of a given set of classes. Then the set of objects forms the data base of the application. The objects contain attributes and methods. Properties of the objects are stored in the attributes. Algorithms which the objects perform are implemented in the methods of the objects. If objects are modified by a user, the consistency of data in the base is destroyed. The data base must be modified in an update to restore its consistency. The sequence of the update operations is not arbitrary, but is governed by dependence between the objects. The situation can be described mathematically with graph theory. The available algorithms for the determination of the update sequence are not suitable when the data base is large. A new update algorithm for large data bases has been developed and is presented in this paper

Stochastic sensitivity of bull and bear states

We study the price dynamics generated by a stochastic version of a Day–Huang type asset market model with heterogenous, interacting market participants. To facilitate the analysis, we introduce a methodology that allows us to assess the consequences of changes in uncertainty on the dynamics of an asset price process close to stable equilibria. In particular, we focus on noise-induced transitions between bull and bear states of the market under additive as well as parametric noise. Our results are obtained by combining the stochastic sensitivity function (SSF) approach, a mixture of analytical and numerical techniques, due to Mil’shtein and Ryashko (1995) with concepts and techniques from the study of non-smooth 1D maps. We find that the stochastic sensitivity of the respective bull and bear equilibria in the presence of additive noise is higher than under parametric noise. Thus, recurrent transitions are likely to be observed already for relatively low intensities of additive noise.publishedVersio

Avaliação das repetições hexanucleotídicas no gene C9orf72 como possível modificador de idade de início da doença em pacientes com doença de Machado-Joseph

A doença de Machado-Joseph (MJD – Machado-Joseph disease), também conhecida como ataxia espinocerebelar tipo 3 (SCA3 – spinocerebellar ataxia type 3), é uma doença neurodegenerativa, com padrão de herança autossômica dominante, causada por uma expansão do trato de repetições CAG no gene ATXN3. Estudos prévios mostram que a idade de início (ii) da doença apresenta uma correlação inversa ao número de repetições CAG no alelo expandido, mas que somente entre 40 e 68% da variação da ii pode ser explicado pelo tamanho da expansão. Considerando que um mecanismo molecular comum para todas as doenças neurodegenerativas foi proposto anteriormente, o restante da variação da correlação pode estar associado ao mecanismo molecular de outras doenças. Expansão da repetição hexanucleotídica (GGGGCC ou G4C2) no gene C9orf72 foi identificado como a etiologia em uma proporção significante dos pacientes de esclerose lateral amiotrófica (ALS – amyotrophic lateral sclerosis), demência frontotemporal (FTD – frontotemporal dementia) e os afetados da comorbidade ALS-FTD. O presente estudo teve como objetivo investigar o tamanho do trato de hexanucleotídeo no gene C9orf72 em pacientes com MJD/SCA3 como um potencial modificador de ii. A genotipagem dos alelos do C9orf72 foi realizada por PCR com primers fluorescentes, seguida de eletroforese capilar, e avaliada no grupo teste e no grupo controle. Foram genotipados 83 pacientes com MJD/SCA3 e 102 controles saudáveis sem história de ataxia. Todos os pacientes e controles foram recrutados no Hospital de Clínicas de Porto Alegre. A expansão patogênica do C9orf72 foi definida como trato contendo mais de 30 repetições hexanucleotídicas. Os indivíduos foram divididos em duas categorias para fins de análises estatísticas: grupo 1) indivíduos com ambos alelos contendo até 6 repetições, inclusive (alelo “pequeno”) e grupo 2) os indivíduos com pelo menos um alelo de 7 até 30 repetições, inclusive (alelo “intermediário”). Nenhum indivíduo com expansão patogênica foi detectado. A frequência alélica de G4C2 foi estabelecida e nenhuma diferença foi observada entre elas. Além disso, não foi encontrada correlação do tamanho do alelo com pacientes de ii precoce e nem com os pacientes de ii tardia. Portanto, nossos resultados indicam que o tamanho do alelo do C9orf72 não atua como fator modificador da idade de início da doença em pacientes com MJD/SCA3.Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3) is a neurodegenerative disorder of an autosomal dominant trait caused by an expansion of a CAG repeat tract in the ATXN3 gene. Previous studies show that age of onset (AO) of the disease is inversely correlated with CAG repeat length in the expanded allele that can explain from 40 to 68% of variation in AO. Considering that a common molecular mechanism for all neurodegenerative diseases has been previously suggested, the key to describing this variation could lie in the molecular biology of other diseases. Hexanucleotide repeat (GGGGCC or G4C2) expansions in C9orf72 were identified as the etiology in a significant portion of patients with amyotrophic lateral sclerosis (ALS), patients with frontotemporal dementia (FTD), and those affected by comorbid ALS-FTD. Taking this into consideration, our aim was to investigate C9orf72 hexanucleotide tract length in MJD/SCA3 patients as a potential modifier of AO. After establishing a reliable protocol to genotype C9orf72 alleles using PCR with fluorescent primers followed by capillary electrophoresis, 83 MJD/SCA patients and 102 healthy controls with no history of ataxia were genotyped. All individuals were recruited from the Hospital de Clínicas de Porto Alegre. Pathogenic expansions were defined as alleles containing more than 30 hexanucleotide repeats. Individuals were divided into two categories for statistical analysis: group 1) those with both alleles containing up to 6 repeats (“small” alleles) and group 2) those with one or both alleles of 7 up to 30 repeats (“intermediate” alleles). No pathogenic expansions were detected. Allelic distribution was established, and no difference was observed between groups. In addition, neither early-onset nor late-onset MJD/SCA3 patients have shown to be correlated with neither the small nor the intermediary C9orf72 genotype so far. Therefore, results obtained in this study indicate that C9orf72 allele length is not a modifier of age of onset in MJD/SCA3 patients