phi-fourth model on a circle

The four dimensional critical scalar theory at equilibrium with a thermal bath at temperature $T$ is considered. The thermal equilibrium state is labeled by $n$ the winding number of the vacua around the compact imaginary-time direction which compactification radius is 1/T. The effective action for zero modes is a three dimensional $\phi^4$ scalar theory in which the mass of the the scalar field is proportional to $n/T$ resembling the Kaluza-Klein dimensional reduction. Similar results are obtained for the theory at zero temperature but in a one-dimensional potential well. Since parity is violated by the vacua with odd vacuum number $n$, in such cases there is also a cubic term in the effective potential. The $\phi^3$-term contribution to the vacuum shift at one-loop is of the same order of the contribution from the $\phi^4$-term in terms of the coupling constant of the four dimensional theory but becomes negligible as $n$ tends to infinity. Finally, the relation between the scalar classical vacua and the corresponding SU(2) instantons on $S^1\times{\mathbb R}^3$ in the 't Hooft ansatz is studied.Comment: 9 pages, revtex4, to appear in Phys.Lett.

Quantum statistical correlations in thermal field theories: boundary effective theory

We show that the one-loop effective action at finite temperature for a scalar field with quartic interaction has the same renormalized expression as at zero temperature if written in terms of a certain classical field $\phi_c$, and if we trade free propagators at zero temperature for their finite-temperature counterparts. The result follows if we write the partition function as an integral over field eigenstates (boundary fields) of the density matrix element in the functional Schr\"{o}dinger field-representation, and perform a semiclassical expansion in two steps: first, we integrate around the saddle-point for fixed boundary fields, which is the classical field $\phi_c$, a functional of the boundary fields; then, we perform a saddle-point integration over the boundary fields, whose correlations characterize the thermal properties of the system. This procedure provides a dimensionally-reduced effective theory for the thermal system. We calculate the two-point correlation as an example.Comment: 13 pages, 1 figur

Uniformidade de distribuição de água e ions em diferentes profundidades do solo com bananeira fertirrigada.

A uniformidade de distribuição (CUD), de água e nutrientes via fertirrigação por microaspersão em bananeira tem sido avaliada em condições de solo nu, entretanto, é necessário avaliar com o solo sob cobertura morta, o que altera as propriedades físicas do solo nessa condição. Esse trabalho teve como objetivo avaliar a uniformidade de distribuição de água, da Condutividade elétrica aparente (CEa), dos íons potássio e nitrato no entorno do microaspersor após uma fertirrigação em um pomar de bananeira (BRS Princesa). O experimento seguiu o delineamento de blocos casualizados em esquemas de parcelas subdivididas, com os tratamentos T1: com cobertura e T2: sem cobertura na parcela, profundidade de 0,20 0,40 e 0,60 m na sub parcela. As avaliações foram feitas 1 e 24 horas após a fertirrigação. A avaliação foi feita com sondas de TDR instaladas a 0,20; 0,40 e 0,60 m, próximo de coletores de água dispostos em uma malha de 0,50 x 0,50 m com o microaspersor de vazão 53Lh-¹ instalado entre quatro plantas. O tratamento com cobertura morta apresentou maior coeficiente de uniformidade de distribuição (CUD) em todas as profundidades comparado ao tratamento sem cobertura enquanto a condutividade elétrica teve comportamento inverso onde o CUD foi superior no tratamento sem cobertura,. Após a fertirrigação a umidade do solo com cobertura foi estatisticamente superior a do sem cobertura, entretanto esses valores se aproximaram 24 horas após

Photometric Properties of 47 Clusters of Galaxies: I. The Butcher-Oemler Effect

We present gri CCD photometry of 44 Abell clusters and 4 cluster candidates. Twenty one clusters in our sample have spectroscopic redshifts. Fitting a relation between mean g, r and i magnitudes, and redshift for this subsample, we have calculated photometric redshifts for the remainder with an estimated accuracy of 0.03. The resulting redshift range for the sample is 0.03<z<0.38. Color-magnitude diagrams are presented for the complete sample and used to study evolution of the galaxy population in the cluster environment. Our observations show a strong Butcher-Oemler effect (Butcher & Oemler 1978, 1984), with an increase in the fraction of blue galaxies (f_B) with redshift that seems more consistent with the steeper relation estimated by Rakos and Schombert (1995) than with the original one by Butcher & Oemler (1984). However, in the redshift range between ~ 0.08 and 0.2, where most of our clusters lie, there is a wide range of f_B values, consistent with no redshift evolution of the cluster galaxy population. A large range of f_B values is also seen between ~ 0.2 and 0.3, when Smail at al. (1998) x-ray clusters are added to our sample. The discrepancies between samples underscore the need for an unbiased sample to understand how much of the Butcher-Oemler effect is due to evolution, and how much to selection effects. We also tested the idea proposed by Garilli et al. (1996) that there is a population of unusually red galaxies which could be associated either with the field or clusters, but we find that these objects are all near the limiting magnitude of the images (20.5<r<22) and have colors that are consistent with those expected for stars or field galaxies at z ~ 0.7.Comment: 35 pages including 8 figures, submitted to A

Detection Of Somatic Mutations Of The Pig-a Gene In Brazilian Patients With Paroxysmal Nocturnal Hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal syndrome characterized by intravascular hemolysis mediated by complement, thrombotic events and alterations in hematopoiesis. Basically, the molecular events which underlie the complexity of the syndrome consist of the absence of the glycosylphosphatidylinositol (GPI) anchor as a consequence of somatic mutations in the PIG-A gene, located on the X chromosome. The GPI group is responsible for the attachment of many proteins to the cytoplasmic membrane. Two of them, CD55 and CD59, have a major role in the inhibition of the action of complement on the cellular membrane of blood cells. The absence of GPI biosynthesis can lead to PNH. Since mutations in the PIG-A gene are always present in patients with PNH, the aim of this study was to characterize the mutations in the PIG-A gene in Brazilian patients. The analysis of the PIG-A gene was performed using DNA samples derived from bone marrow and peripheral blood. Conformation-sensitive gel electrophoresis was used for screening the mutation and sequencing methods were used to identify the mutations. Molecular analysis permitted the identification of three point mutations in three patients: one G-->A transition in the 5' portion of the second intron, one T-->A substitution in the second base of codon 430 (Leu430-->stop), and one deletion DeltaA in the third base of codon 63. This study represents the first description of mutations in the PIG-A gene in a Brazilian population.34763-

Efeito da secagem de Brachiaria brizantha cv. Marandu sobre a hidrólise enzimática de seus polissacarídeos.

O objetivo deste trabalho foi avaliar o efeito de secagem sobre o pré-tratamento químico e hidrólise enzimática de brachiaria brizantha