Second Stage String Fragmentation Model

A string model, advocated by Bowler, provides a physical and intuitive picture of heavy quark fragmentation. When supplemented by an ad hoc factor of (1-z), to suppress fragmentation near z=1, it supplies an excellent fit to the data. We extend Bowler's model by accounting for the further decay of the massive mesonic states produced by the initial string breaking. We find that each subsequent string break and cascade decay beyond the first, introduces a factor of (1-z). Furthermore we find that including a finite mass for the quarks, which pop out of the vacuum and split the string, forces the first string breaking to produce massive states requiring further decay. This sequence terminates at the second stage of fragmentation where only relatively "light" heavy meson systems are formed. Thus we naturally account for the phenomenologically required factor of (1-z). We also predict that the ratio of (primary) fragments-vector/(vector plus scalar) should be .61. Our second stage string fragmentation model provides an appealing picture of heavy quark fragmentation.Comment: 15 page

Prediction of charm-production fractions in neutrino interactions

The way a charm-quark fragments into a charmed hadron is a challenging problem both for the theoretical and the experimental particle physics. Moreover, in neutrino induced charm-production, peculiar processes occur such as quasi-elastic and diffractive charm-production which make the results from other experiments not directly comparable. We present here a method to extract the charmed fractions in neutrino induced events by using results from $e^+e^-$, $\pi N$, $\gamma N$ experiments while taking into account the peculiarities of charm-production in neutrino interactions. As results, we predict the fragmentation functions as a function of the neutrino energy and the semi-muonic branching ratio, $B_\mu$, and compare them with the available data

Light Neutralinos in B-Decays

We consider the decays of a $B_s$-meson into a pair of lightest supersymmetric particles (LSP) in the minimal supersymmetric standard model. It is found that the parameter space for light LSP's in the range of 1 GeV can be appreciably constrained by looking for such decays.Comment: 9 pages, LaTex, 2 figures (hard copies of the figures available from the Authors on request

Colheita e pós-colheita da batata-semente.

bitstream/item/120257/1/digitalizar0003.pd

Rhythmic TMS as a Feasible Tool to Uncover the Oscillatory Signatures of Audiovisual Integration

Multisensory integration is quintessential to adaptive behavior, with clinical populations showing significant impairments in this domain, most notably hallucinatory reports. Interestingly, altered cross-modal interactions have also been reported in healthy individuals when engaged in tasks such as the Sound-Induced Flash-Illusion (SIFI). The temporal dynamics of the SIFI have been recently tied to the speed of occipital alpha rhythms (IAF), with faster oscillations entailing reduced temporal windows within which the illusion is experienced. In this regard, entrainment-based protocols have not yet implemented rhythmic transcranial magnetic stimulation (rhTMS) to causally test for this relationship. It thus remains to be evaluated whether rhTMS-induced acoustic and somatosensory sensations may not specifically interfere with the illusion. Here, we addressed this issue by asking 27 volunteers to perform a SIFI paradigm under different Sham and active rhTMS protocols, delivered over the occipital pole at the IAF. Although TMS has been proven to act upon brain tissues excitability, results show that the SIFI occurred for both Sham and active rhTMS, with the illusory rate not being significantly different between baseline and stimulation conditions. This aligns with the discrete sampling hypothesis, for which alpha amplitude modulation, known to reflect changes in cortical excitability, should not account for changes in the illusory rate. Moreover, these findings highlight the viability of rhTMS-based interventions as a means to probe the neuroelectric signatures of illusory and hallucinatory audiovisual experiences, in healthy and neuropsychiatric populations

Desempenho de cultivares de batata sob condições ambientais de estiagem.

BRS Ana é uma cultivar de batata que apresenta elevado potencial produtivo, película rosada, ciclo vegetativo tardio e grande vigor de planta; apresenta ainda tolerância à falta de água, provavelmente devido ao seu sistema radicular bem desenvolvido (PEREIRA et al, 2008). Ágata é a cultivar de película amarela mais cultivada no país, apresenta elevado potencial produtivo, porém, para isso, necessita de grande quantidade de insumos como adubos e defensivos, e é sabidamente sensível à falta de água (ROHR et al, 2001). Já a cultivar BRS Clara, possui película amarela, e em condições de campo mostra certa tolerância à falta de água, esta tolerância também foi observada em laboratório (ROHR et al, 2001). Dentre as espécies vegetais cultivadas pelo homem, a batata é uma das mais sensíveis à falta de água. Sendo os efeitos adversos máximos durante o período de estolonização e formação dos tubérculos. De maneira geral, essa cultura consome de 300 a 800 mm de água durante todo o ciclo, dependendo principalmente, das condições climáticas predominantes (GARCIA, 2003). A resposta diferencial de cultivares de batata ao estresse hídrico indica que há variabilidade genética para a tolerância à seca no germoplasma de batata (LEVY, 1983). Entretanto, diante da complexidade de fenotipagem para a resposta à seca, ainda são limitados os estudos abordando o estresse hídrico de seca para esta cultura (ROHR et al, 2001). O objetivo do presente trabalho foi verificar o desempenho das cultivares de batata BRS Ana, BRS Clara e Agata, cultivadas sob condições climáticas de estiagem, em relação ao rendimento de tubérculos

Effect of potassium sources on potato tuber yield and chip quality.

The aim of this work was to evaluate the effect of these two potassium sources on yield, specific gravity and chip color of potato chipping cultivars. The experiment was carried out on a Dystrophic Red Latosol, in Canoinhas, Brazil, in spring season 2016

FATZ, a filamin-, actinin-, and telethonin-binding protein of the Z-disc of skeletal muscle

We report the identification and characterization of a novel 32-kDa protein expressed in skeletal muscle and located in the Z-disc of the sarcomere. We found that this protein binds to three other Z-disc proteins; therefore, we have-named it FATZ, gamma -filamin/ABP-L, alpha -actinin and telethonin binding protein of the Z-disc. From yeast two-hybrid experiments we are able to show that the SR3-SR4 domains of alpha -actinin 2 are required to bind the COOH-terminal region of the FATZ as does gamma -filamin/ABP-L, Furthermore, by using a glutathione S-transferase overlay assay we find that FATZ also binds telethonin. The level of FATZ protein in muscle cells increases during differentiation, being clearly detectable before the onset of myosin, Although FATZ has no known interaction domains, it would appear to be involved in a complex network of interactions with other Z-band components. On the basis of the information known about its binding partners, we could envisage a central role for FATZ in the: myofibrillogenesis, After screening our muscle expressed sequence tag data base and the public expressed sequence tag data bases, we were able to assemble two other muscle transcripts that show a high level of identity with FATZ in two different domains. Therefore, FATZ may be the first member of a small family of novel muscle proteins

Cultivo orgânico de batata no sudoeste do paraná

bitstream/item/163877/1/digitalizar0216.pd

Momentum Distribution in the Decay B-->J/psi+X

We combine the NRQCD formalism for the inclusive color singlet and octet production of charmonium states with the parton and the ACCMM model, respectively, and calculate the momentum distribution in the decay B-->J/psi+X. Neglecting the kinematics of soft gluon radiation, we find that the motion of the b quark in the bound state can account, to a large extent, for the observed spectrum. The parton model gives a satisfactory presentation of the data, provided that the heavy quark momentum distribution is taken to be soft. To be explicit, we obtain epsilon_p=O(0.008-0.012) for the parameter of the Peterson et al. distribution function. The ACCMM model can account for the data more accurately. The preferred Fermi momentum p_F=O(0.57 GeV) is in good agreement with recent studies of the heavy quark's kinetic energy.Comment: revised version to be published in Phys. Rev. D; 27 pages, LaTeX, 7 eps figures, uses a4wide.sty, epsfig.sty and amssymb.st