238 research outputs found

    Gravitational Smearing of Minimal Supersymmetric Unification Predictions

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    A short and mean paper.Comment: 10 pages total + 1 postscript figure (included), revised: all lines are TRULY < 70 characters long (try it!); LBL-32905, UCB-PTH-92/3

    Universality of Thermodynamic Constants Governing Biological Growth Rates

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    Background: Mathematical models exist that quantify the effect of temperature on poikilotherm growth rate. One family of such models assumes a single rate-limiting ‘master reaction ’ using terms describing the temperature-dependent denaturation of the reaction’s enzyme. We consider whether such a model can describe growth in each domain of life. Methodology/Principal Findings: A new model based on this assumption and using a hierarchical Bayesian approach fits simultaneously 95 data sets for temperature-related growth rates of diverse microorganisms from all three domains of life, Bacteria, Archaea and Eukarya. Remarkably, the model produces credible estimates of fundamental thermodynamic parameters describing protein thermal stability predicted over 20 years ago. Conclusions/Significance: The analysis lends support to the concept of universal thermodynamic limits to microbial growth rate dictated by protein thermal stability that in turn govern biological rates. This suggests that the thermal stability of proteins is a unifying property in the evolution and adaptation of life on earth. The fundamental nature of this conclusion has importance for many fields of study including microbiology, protein chemistry, thermal biology, and ecological theory including, for example, the influence of the vast microbial biomass and activity in the biosphere that is poorly described in current climate models

    Application of an electronic nose coupled with fuzzy-wavelet network for the detection of meat spoilage

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    Food product safety is one of the most promising areas for the application of electronic noses. During the last twenty years, these sensor-based systems have made odour analyses possible. Their application into the area of food is mainly focused on quality control, freshness evaluation, shelf-life analysis and authenticity assessment. In this paper, the performance of a portable electronic nose has been evaluated in monitoring the spoilage of beef fillets stored either aerobically or under modified atmosphere packaging, at different storage temperatures. A novel multi-output fuzzy wavelet neural network model has been developed, which incorporates a clustering pre-processing stage for the definition of fuzzy rules. The dual purpose of the proposed modelling approach is not only to classify beef samples in the relevant quality class (i.e. fresh, semi-fresh and spoiled), but also to predict their associated microbiological population. Comparison results against advanced machine learning schemes indicated that the proposed modelling scheme could be considered as a valuable detection methodology in food microbiology

    Predictions of SUSY Masses in the Minimal SUSY GUT

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    The MSSM distinguishes itself from other GUT's by a successful prediction of many unrelated phenomena with a minimum number of parameters. Among them: a) Unification of the couplings constants; b)Unification of the masses; c) Proton decay; d) Electroweak symmetry breaking. A combined fit of the free parameters in the MSSM to these low energy constraints shows that the MSSM model can satisfy these constraints simultaneously. From the fitted parameters the masses of the as yet unobserved superpartners of the SM particles are predicted. The 2nd order QCD coupling constant is required to be between 0.108 and 0.132. It is shown that a top mass of 174±16174\pm16 GeV, as suggested recently by the CDF Collaboration, constrains the mixing angle between the Higgs doublets in the MSSM to: 1.2<\tb<5.5 at the 90% C.L.. The most probable value corresponds to \tb = 1.56, which leads to a stop mass below the top mass. In this case the stop production in ppˉp\bar{p} collisions would contribute to the top signature. This could be an explanation for the large effective ttˉt\bar{t} cross section observed by CDF.Comment: latex + eps fig IEKP-KA/94-0

    Sex Ratio at Birth and Mortality Rates Are Negatively Related in Humans

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    Evolutionary theory posits that resource availability and parental investment ability could signal offspring sex selection, in order to maximize reproductive returns. Non-human studies have provided evidence for this phenomenon, and maternal condition around the time of conception has been identified as most important factor that influence offspring sex selection. However, studies on humans have reported inconsistent results, mostly due to use of disparate measures as indicators of maternal condition. In the present study, the cross-cultural differences in human natal sex ratio were analyzed with respect to indirect measures of condition namely, life expectancy and mortality rate. Multiple regression modeling suggested that mortality rates have distinct predictive power independent of cross-cultural differences in fertility, wealth and latitude that were earlier shown to predict sex ratio at birth. These findings suggest that sex ratio variation in humans may relate to differences in parental and environmental conditions

    First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

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    Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto- noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

    Estimulação diafragmática elétrica transcutânea (EDET) para fortalecimento muscular respiratório: estudo clínico controlado e randomizado

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    O objetivo do estudo foi demonstrar o efeito de dois protocolos da estimulação diafragmática elétrica transcutânea (EDET) sobre a força muscular respiratória de mulheres saudáveis, sendo um protocolo segundo Geddes et al. (1988) e outro padronizado pelo equipamento Phrenics. Mulheres saudáveis foram divididas em 3 grupos: Controle (n=7); EDET com Phrenics (n=7) e EDET com Dualpex (n=7), sendo o tratamento realizado 2 vezes por semana, durante 6 semanas (12 sessões). Foram avaliadas a pressão inspiratória máxima (PImáx) e pressão expiratória máxima (PEmáx), antes e após o tratamento. A análise estatística foi realizada pelo teste Shapiro-Wilk e Kruskal Wallis com pós-hoc de Dunn (p<0,05). Os dois grupos experimentais apresentaram aumento na PImáx (Phrenics: 32,9%; Dualpex: 63,2%) e na PEmáx (Phrenics: 44,7%; Dualpex: 60,9%), diferentemente do Controle que não apresentou diferença. Em conclusão, os dois protocolos de EDET promoveram aumento da força muscular inspiratória e expiratória em mulheres saudáveis

    Female chacma baboons form strong, equitable, and enduring social bonds

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    Analyses of the pattern of associations, social interactions, coalitions, and aggression among chacma baboons (Papio hamadryas ursinus) in the Okavango Delta of Botswana over a 16-year period indicate that adult females form close, equitable, supportive, and enduring social relationships. They show strong and stable preferences for close kin, particularly their own mothers and daughters. Females also form strong attachments to unrelated females who are close to their own age and who are likely to be paternal half-sisters. Although absolute rates of aggression among kin are as high as rates of aggression among nonkin, females are more tolerant of close relatives than they are of others with whom they have comparable amounts of contact. These findings complement previous work which indicates that the strength of social bonds enhances the fitness of females in this population and support findings about the structure and function of social bonds in other primate groups
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