359 research outputs found
Generalizing Planck's distribution by using the Carati-Galgani model of molecular collisions
Classical systems of coupled harmonic oscillators are studied using the
Carati-Galgani model. We investigate the consequences for Einstein's conjecture
by considering that the exchanges of energy, in molecular collisions, follows
the L\'evy type statistics. We develop a generalization of Planck's
distribution admitting that there are analogous relations in the equilibrium
quantum statistical mechanics of the relations found using the nonequilibrium
classical statistical mechanics approach. The generalization of Planck's law
based on the nonextensive statistical mechanics formalism is compatible with
the our analysis.Comment: 10 pages, 3 figure
Methods for Investigating the UPR in Filamentous Fungi
Filamentous fungi have a high-capacity secretory system and are therefore widely exploited for the industrial production of native and heterologous proteins. However, in most cases, the yields of nonfungal proteins are significantly lower than those obtained for fungal proteins. One well-studied bottleneck appears to be the result of slow or aberrant folding of heterologous proteins in the ER during the early stages of secretion within the endoplasmic reticulum, leading to stress responses in the host, including the unfolded protein response (UPR). Most of the key elements constituting the signal transduction pathway of the UPR in Saccharomyces cerevisiae have been identified in filamentous fungi, including the central activation mechanism of the pathway, that is, the stress-induced splicing of an unconventional (nonspliceosomal) intron in orthologs of the HAC1 mRNA. This splicing event relieves a translational block in the HAC1 mRNA, allowing for the translation of the bZIP transcription factor Hac1p that regulates the expression of UPR target genes. The UPR is involved in regulating the folding, yield, and delivery of secretory proteins and that has consequences for fungal lifestyles, including virulence and biotechnology. The recent releases of genome sequences of several species of filamentous fungi and the availability of DNA arrays, GeneChips, and deep sequencing methodologies have provided an unprecedented resource for exploring expression profiles in response to secretion stresses. Furthermore, genome-wide investigation of translation profiles through polysome analyses is possible, and here, we outline methods for the use of such techniques with filamentous fungi and, principally, Aspergillus niger. We also describe methods for the batch and controlled cultivation of A. niger and for the replacement and study of its hacA gene, which provides either a UPR-deficient strain or a constitutively activated UPR strain for comparative analysis with its wild type. Although we focus on A. niger, the utility of the hacA-deletion strategy is also described for use in investigating the virulence of the plant pathogen Alternaria brassicicola
Carcass characteristics and meat quality of lambs fed high levels of spineless cactus in the diet
The objective was to evaluate the effect of increasing the dietary inclusion of spineless cactus (Nopalea cochenillifera Salm Dyck) on the carcass characteristics and meat quality of confined lambs. Thirty-two male Santa Inês lambs with an average age of 140 days and an initial body weight of 20.4 ± 2.60 kg were used in this study. The lambs were housed in individual stalls for 70 days and individually fed a ration with spineless cactus included at 0, 241, 519, or 753 g/kg of dry matter (DM). The lambs were slaughtered, and characteristics of the carcass and meat were recorded and analysed. Inclusion of spineless cactus had a quadratic effect on the bodyweight at slaughter and on the empty bodyweight of the lambs. The inclusion of 500 g/kg of spineless cactus provided the highest predicted cold carcass weight (16.03 kg). There was a quadratic effect of the inclusion of spineless cactus on the weight of meat cuts and leg composition of lambs. The inclusion of spineless cactus did not influence pH, tenderness, and water-retention capacity of the meat. However, the intramuscular fat content increased 1 mg for every 10 g/kg inclusion of spineless cactus in the diet. Quadratic effects were observed of the inclusion of spineless cactus on the weights of the liver, heart, rumen, blood, skin and internal fat of the lambs. Up to 500 g/kg of spineless cactus could be included in the diet of confined lambs
Self-Organized Criticality and Stock Market Dynamics: an Empirical Study
The Stock Market is a complex self-interacting system, characterized by an
intermittent behaviour. Periods of high activity alternate with periods of
relative calm. In the present work we investigate empirically about the
possibility that the market is in a self-organized critical state (SOC). A
wavelet transform method is used in order to separate high activity periods,
related to the avalanches of sandpile models, from quiescent.
A statistical analysis of the filtered data show a power law behaviour in the
avalanche size, duration and laminar times. The memory process, implied by the
power law distribution, of the laminar times is not consistent with classical
conservative models for self-organized criticality. We argue that a
``near-SOC'' state or a time dependence in the driver, which may be chaotic,
can explain this behaviour.Comment: 16 pages, 13 figures. In press: Physica
K* nucleon hyperon form factors and nucleon strangeness
A crucial input for recent meson hyperon cloud model estimates of the nucleon
matrix element of the strangeness current are the nucleon-hyperon-K* (NYK*)
form factors which regularize some of the arising loops. Prompted by new and
forthcoming information on these form factors from hyperon-nucleon potential
models, we analyze the dependence of the loop model results for the
strange-quark observables on the NYK* form factors and couplings. We find, in
particular, that the now generally favored soft N-Lambda-K* form factors can
reduce the magnitude of the K* contributions in such models by more than an
order of magnitude, compared to previous results with hard form factors. We
also discuss some general implications of our results for hadronic loop models.Comment: 9 pages, 8 figures, new co-author, discussion extended to the
momentum dependence of the strange vector form factor
Prospective evaluation of glutamine and phospholipids levels in first degree relatives of patients with Type 1 Diabetes from a multiethnic population
A dysregulation in the metabolism of lipids may be an early marker of autoimmunity in Type 1 Diabetes (T1D). It would be of general importance to identify metabolic patterns that would predict the risk for T1D later in life. The aim of this study was to perform a prospective evaluation of glutamine and phospholipids levels in Brazilian first degree relatives (FDR) of patients with T1D in a mean interval of 5 years
Instanton Effects in QCD at High Baryon Density
We study instanton effects in QCD at very high baryon density. In this regime
instantons are suppressed by a large power of , where
is the QCD scale parameter and is the baryon chemical
potential. Instantons are nevertheless important because they contribute to
several physical observables that vanish to all orders in perturbative QCD. We
study, in particular, the chiral condensate and its contribution to the masses of Goldstone bosons in the CFL phase of QCD
with flavors. We find that at densities , where
is the density of nuclear matter, the result is dominated by large
instantons and subject to considerable uncertainties. We suggest that these
uncertainties can be addressed using lattice calculations of the instanton
density and the pseudoscalar diquark mass in QCD with two colors. We study the
topological susceptibility and Witten-Veneziano type mass relations in both
and QCD.Comment: 27 pages, 8 figures, minor revision
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