915 resultados para Z(p)-index


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This study was designed to determine the effect of Mangifera indica flowers decoction, on the acute and subacute models of induced ulcer in mice and rats. A single oral administration of the aqueous decoction (AD) from M. indica up to a dose of 5 g/kg, p.o. did not produce any signs or symptom of toxicity in the treated animals. The oral pre-treatment with AD (250, 500 and 1000 mg/kg) in rats with gastric lesions induced by ethanol, decreased the gastric lesions from 89.0 +/- 6.71 (control group) to 9.25 +/- 2.75, 4.50 +/- 3.30 and 0, respectively. Pretreatment with AD (250, 500 and 1000 mg/kg) to mice with HCl/ethanol- or stress-induced gastric lesions resulted in a dose-dependent significant decrease of lesion index. In the piroxicam-induced gastric lesions, the gastroprotective effect of AD was reducing with the increase of the AD dose. In the pylorus-ligature, AD (p.o.) significantly decreased the acid output indicating the antisecretory property involved in the gastroprotective effect of M. indica. Treatment with AD during 14 consecutive days significantly accelerated the healing process in subacute gastric ulcer induced by acetic acid in rats. Pretreatment with N-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO-synthase, did not abolish the gastroprotective effects (99% with saline versus 80% With L-NAME) of AD against ethanol-induced gastric lesions. Pretreatment with N-ethylmaleimide (NEM), a blocker of endogenous sulphydryl group, significantly abolished the protective effects of AD against ethanol-induced gastric ulcers (95% with saline versus 47% with NEM). Phytochemical screening showed the presence of steroids, triterpenes, phenolic compounds and flavonoids. Estimation of the global polyphenol content in the AD was performed by Folin-Ciocalteu method and showed approximately 53% of total phenolic on this extract. These findings indicate the potential gastroprotective and ulcer-healing properties of aqueous decoction of M. indica flowers and further support its popular use in gastrointestinal disorders in Caribbean. (c) 2005 Elsevier B.V.. All rights reserved.

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Foram amostrados 17 trechos de riachos com 100 m de extensão, todos de ordem igual ou menor a três, ao longo de ambas as margens do canal principal do Rio Paranapanema, SP e PR. O ponto médio de cada trecho foi georreferenciado via satélite com receptor GPS e o uso de metodologia padronizada de coleta de dados ambientais e peixes (baseada principalmente na pesca elétrica), possibilitou a obtenção das seguintes informações em cada local: 1) composição taxonômica da ictiofauna e contribuição, em termos de número de indivíduos e biomassa, de cada espécie para a ictiofauna local como um todo; 2) documentação fotográfica de espécimes representativos de cada espécie coletada com sua coloração natural; 3) descrição de cada ambiente coletado, com ilustrações fotográficas coloridas, e seus principais parâmetros bióticos e abióticos. No total foram coletados 3.683 exemplares, pertencentes a seis ordens, 16 famílias, 37 gêneros e 52 espécies, com biomassa total de 16,8 kg. Das espécies coletadas, aproximadamente 36% pertencem a ordem Siluriformes, 36% a Characiformes, 11% a Gymnotiformes, 10% a Perciformes, 4% a Cyprinodontiformes e 2% a Synbranchiformes. As espécies mais abundantes em termos de número de indivíduos foram Astyanax altiparanae (15,2%) e Astyanax sp. 1 (12,3%); aquelas com maior biomassa foram A. altiparanae (28%) e Geophagus brasiliensis (13%). A composição da ictiocenose em termos de abundância e biomassa por família indica a predominância expressiva de Characidae, seguida por Loricariidae, Pimelodidae e Cichlidae. Dentre os trechos amostrados, o trecho 14 (24 espécies) e o 13 (cinco espécies), apresentaram a maior e a menor riqueza em espécies, respectivamente, coincidindo com os valores obtidos para o índice de diversidade específica de Shannon-Wienner (H´= 0,99 e 0,32, respectivamente). A riqueza média encontrada foi de 11 espécies por trecho de riacho. Na estimativa de riqueza por extrapolação para o conjunto total de riachos amostrados na bacia do rio Paranapanema, obtivemos um valor de 69 espécies (erro padrão igual a quatro) indicando ser necessário um esforço amostral adicional moderado para atingir a assíntota da curva. Das 52 espécies coletadas, oito (aproximadamente 15% do total) são seguramente novas, cinco (aproximadamente 10% do total) possuem status taxonômico ainda indefinido, enquanto outras três (aproximadamente 6% do total) são espécies introduzidas. Analisando a estrutura trófica e espacial da ictiocenose estudada, as 10 espécies numericamente dominantes nos riachos estudados dividem-se, em ordem decrescente de importância numérica, em quatro guildas: onívoros nectônicos; invertívoros bentônicos; perifitívoros; e onívoros bentônicos. Uma chave de identificação para todas as espécies de peixes coletadas durante este estudo é fornecida ao final deste trabalho.

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In this work we make some contributions to the theory of actions of abelian p-groups on the n-Torus T-n. Set congruent to Z(pk1)(h1) x Z(pk2)(h2) x...x Z(pkr)(hr), r >= 1, k(1) >= k(2) >=...>= k(r) >= 1, p prime. Suppose that the group H acts freely on T-n and the induced representation on pi(1)(T-n) congruent to Z(n) is faithful and has first Betti number b. We show that the numbers n, p, b, k(i) and h(i) (i = 1,..,r) satisfy some relation. In particular, when H congruent to Z(p)(h), the minimum value of n is phi(p) + b when b >= 1. Also when H congruent to Z(pk1) x Z(p) the minimum value of n is phi(p(k1)) + p - 1 + b for b >= 1. Here phi denotes the Euler function.

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A loop is said to be automorphic if its inner mappings are automorphisms. For a prime p, denote by A(p) the class of all 2-generated commutative automorphic loops Q possessing a central subloop Z congruent to Z(p) such that Q/Z congruent to Z(p) x Z(p). Upon describing the free 2-generated nilpotent class two commutative automorphic loop and the free 2-generated nilpotent class two commutative automorphic p-loop F-p in the variety of loops whose elements have order dividing p(2) and whose associators have order dividing p, we show that every loop of A(p) is a quotient of F-p by a central subloop of order p(3). The automorphism group of F-p induces an action of GL(2)(p) on the three-dimensional subspaces of Z(F-p) congruent to (Z(p))(4). The orbits of this action are in one-to-one correspondence with the isomorphism classes of loops from A(p). We describe the orbits, and hence we classify the loops of A(p) up to isomorphism. It is known that every commutative automorphic p-loop is nilpotent when p is odd, and that there is a unique commutative automorphic loop of order 8 with trivial center. Knowing A(p) up to isomorphism, we easily obtain a classification of commutative automorphic loops of order p(3). There are precisely seven commutative automorphic loops of order p(3) for every prime p, including the three abelian groups of order p(3).

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We report transverse momentum (p(T) <= 15 GeV/c) spectra of pi(+/-), K-+/-, p, (p) over bar, K-0(S), and rho(0) at midrapidity in p + p and Au + Au collisions at root s(NN) = 200 GeV. Perturbative QCD calculations are consistent with pi(+/-) spectra in p + p collisions but do not reproduce K and p((p) over bar) spectra. The observed decreasing antiparticle-to-particle ratios with increasing p(T) provide experimental evidence for varying quark and gluon jet contributions to high-p(T) hadron yields. The relative hadron abundances in Au + Au at p(T) >= 8 GeV/c are measured to be similar to the p + p results, despite the expected Casimir effect for parton energy loss.

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We report STAR measurements of the longitudinal double-spin asymmetry A(LL), the transverse singlespin asymmetry A(N), and the transverse double-spin asymmetries A(Sigma) and A(TT) for inclusive jet production at mid-rapidity in polarized p + p collisions at a center-of-mass energy of root s = 200 GeV. The data represent integrated luminosities of 7.6 pb(-1) with longitudinal polarization and 1.8 pb(-1) with transverse polarization, with 50%-55% beam polarization, and were recorded in 2005 and 2006. No evidence is found for the existence of statistically significant jet A(N), A(Sigma), or A(TT) at mid-rapidity. Recent model calculations indicate the A(N) results may provide new limits on the gluon Sivers distribution in the proton. The asymmetry A(LL) significantly improves the knowledge of gluon polarization in the nucleon.

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We report on the mid-rapidity mass spectrum of di-electrons and cross sections of pseudoscalar and vector mesons via e(+) e(-) decays, from root s = 200 GeV p + p collisions, measured by the large-acceptance experiment STAR at the Relativistic Heavy Ion Collider. The ratio of the di-electron continuum to the combinatorial background is larger than 10% over the entire mass range. Simulations of di-electrons from light-meson decays and heavy-flavor decays (charmonium and open charm correlation) are found to describe the data. The extracted omega -> e(+) e(-) invariant yields are consistent with previous measurements. The mid-rapidity yields (dN/dy) of phi and J/psi are extracted through their di-electron decay channels and are consistent with the previous measurements of phi -> K+ K- and J/psi -> e(+) e(-). Our results suggest a new upper limit of the branching ratio of the eta -> e(+) e(-) of 1.7 x 10(-5) at the 90% confidence level.

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We report measurements of charmed-hadron (D-0, D*) production cross sections at midrapidity in p + p collisions at a center-of-mass energy of 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via the hadronic decays D-0 -> K- pi(+), D*(+) -> D-0 pi(+) -> K-pi(+)pi(+) and their charge conjugates, covering the p(T) range of 0.6-2.0 and 2.0-6.0 GeV/c for D-0 and D*(+), respectively. From this analysis, the charm-pair production cross section at midrapidity is d sigma/dy vertical bar(c (c) over bar)(y-0) = 170+/-45(stat)(-59)(+38()sys) mu b. The extracted charm-pair cross section is compared to perturbative QCD calculations. The transverse momentum differential cross section is found to be consistent with the upper bound of a fixed-order next-to-leading logarithm calculation.

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Measurements of the differential cross section and the transverse single-spin asymmetry, A(N), vs x(F) for pi(0) and eta mesons are reported for 0.4 < x(F) < 0.75 at an average pseudorapidity of 3.68. A data sample of approximately 6.3 pb(-1) was analyzed, which was recorded during p(up arrow) + p collisions at root s = 200 GeV by the STAR experiment at RHIC. The average transverse beam polarization was 56%. The cross section for pi(0), including the previously unmeasured region of x(F) > 0.55, is consistent with a perturbative QCD prediction, and the eta/pi(0) cross-section ratio agrees with existing midrapidity measurements. For 0.55 < x(F) < 0.75, the average A(N) for eta is 0.210 +/- 0.056, and that for pi(0) is 0.081 +/- 0.016. The probability that these two asymmetries are equal is similar to 3%.

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On t.p. in the single integral, z̳ and x̳² are superscript; in the double integral, z̳, p̳²y̳², y̳, and x̳² are superscript.

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Mode of access: Internet.

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Before puberty, there are only small sex differences in body shape and composition. During adolescence, sexual dimorphism in bone, lean, and fat mass increases, giving rise to the greater size and strength of the male skeleton. The question remains as to whether there are sex differences in bone strength or simply differences in anthropometric dimensions. To test this, we applied hip structural analysis (HSA) to derive strength and geometric indices of the femoral neck using bone densitometry scans (DXA) from a 6-year longitudinal study in Canadian children. Seventy boys and sixty-eight girls were assessed annually for 6 consecutive years. At the femoral neck, cross-sectional area (CSA, an index of axial strength), subperiosteal width (SPW), and section modulus (Z, an index of bending strength) were determined, and data were analyzed using a hierarchical (random effects) modeling approach. Biological age (BA) was defined as years from age at peak height velocity (PHV). When BA, stature, and total-body lean mass (TB lean) were controlled, boys had significantly higher Z than girls at all maturity levels (P < 0.05). Controlling height and TB lean for CSA demonstrated a significant independent sex by BA interaction effect (P < 0.05). That is, CSA was greater in boys before PHV but higher in girls after PHV The coefficients contributing the greatest proportion to the prediction of CSA, SPW, and Z were height and lean mass. Because the significant sex difference in Z was relatively small and close to the error of measurement, we questioned its biological significance. The sex difference in bending strength was therefore explained by anthropometric differences. In contrast to recent hypotheses, we conclude that the CSA-lean ratio does not imply altered mechanosensitivity in girls because bending dominates loading at the neck, and the Z-lean ratio remained similar between the sexes throughout adolescence. That is, despite the greater CSA in girls, the bone is strategically placed to resist bending; hence, the bones of girls and boys adapt to mechanical challenges in a similar way. (C) 2004 Elsevier Inc. All rights reserved.