Probing the two-scale-factor universality hypothesis by exact rotation symmetry-breaking mechanism

We probe the two-scale factor universality hypothesis by evaluating, firstly explicitly and analytically at the one-loop order, the loop quantum corrections to the amplitude ratios for O($N$) $\lambda\phi^{4}$ scalar field theories with rotation symmetry-breaking in three distinct and independent methods in which the rotation symmetry-breaking mechanism is treated exactly. We show that the rotation symmetry-breaking amplitude ratios turn out to be identical in the three methods and equal to their respective rotation symmetry-breaking ones, although the amplitudes themselves, in general, depend on the method employed and on the rotation symmetry-breaking parameter. At the end, we show that all these results can be generalized, through an inductive process based on a general theorem emerging from the exact calculation, to any loop level and physically interpreted based on symmetry ideas.Comment: 17 pages, 3 figure

Caracterizacao dos frutos de goiabeira e selecao de cultivares na regiao do Submedio Sao Francisco.

O estudo visou a caracterizar frutos de goiabeira e selecionar cultivares produzidas na regiao do Submedio Sao Francisco. Os frutos, colhidos na maturidade fisiologica, foram provenientes da estacao Experimental de Bebedouro, pertencente a Embrapa Semi-Arido e avaliados em delineamento experimental inteiramente casualizado com quatro repeticoes. Os tratamentos compreenderam genotipos de polpa branca (Alabama Safed, Lucknow 49, Banahas, White Selection of Florida e Selecao IPA B 38.1) e vermelha (Paluma, Patillo 2.1, Surubim, Red Selection of Florida e Selecao IPA B 14.3). Avaliaram-se: massa, diametro longitudinal (DL), diametro transversal (DT), relacao DL/DT, espessura da casca, espessura da polpa, solidos soluveis totais (SST), acidez total titulavel (ATT), relacao SST/ATT, pH, acucares soluveis totais (AST) e vitamina C. Os genotipos de polpa branca, exceto Selecao IPA B 38.1, tiveram maiores massas (acima de 145,0g). As menores relacoes DL/DT foram observadas e Banahas (0,98) e Lucknow 49 (1,00), caracterizando frutos redondos. Estas cultivares tiveram tambem maior espessura da polpa. Os maiores valores de SST foram observados em Paluma (10,4 oBrix) e Lucknow 49 (10,9 oBrix). A ATT foi baixa na maioria dos genotipos, exceto Surubim e Selecao IPA B 14,3, e o pH variou de 3,72 a 4,22. Em geral, os genotipos de polpa branca tiveram os maiores teores de AST (5 a 7%) e vitamina C, atingindo 200 mg de acido ascorbico/100g

Avaliação da pinta-preta em progênies de mamoeiro no Estado do Ceará.

O mamoeiro é uma fruteira tropical de grande importância socioeconômica no Brasil e no mundo e o estado do Ceará destaca-se como o terceiro produtor brasileiro de mamão. A ocorrência de doenças é um dos fatores que contribuem para essa produtividade, por causarem perdas severas na cultura (VENTURA et al., 2003)

Formation of a spiral galaxy in a major merger

We use numerical simulations to examine the structure of merger remnants resulting from collisions of gas-rich spiral galaxies. When the gas fraction of the progenitors is small, the remnants structurally and kinematically resemble elliptical galaxies, in agreement with earlier work. However, if the progenitor disks are gas-dominated, new types of outcomes are possible. In fact, we show that a prominent disk may survive in certain cases. To illustrate this scenario, we analyze an extreme example with progenitor galaxies consisting of dark matter halos, pure gas disks, and no bulges, as might be appropriate for mergers at high redshifts. While rapid star formation triggered by tidal torques during the merger forms a central, rotating bulge in the remnant, not all the gas is consumed in the burst. The remaining gas cools very quickly and settles into an extended star-forming disk, yielding an object similar to a spiral galaxy, and not an early type galaxy. This is contrary to the usual view that major mergers invariably destroy disks. The morphological evolution of galaxies can therefore be more complicated than often assumed, and in particular, theoretical constraints based on the fragility of spiral disks need to be reevaluated.Comment: submitted to ApJL, 4 figure

Gemini and Chandra observations of Abell 586, a relaxed strong-lensing cluster

We analyze the mass content of the massive strong-lensing cluster Abell 586 ($z = 0.17$). We use optical data (imaging and spectroscopy) obtained with the Gemini Multi-Object Spectrograph (GMOS) mounted on the 8-m Gemini-North telescope, together with publicly available X-ray data taken with the \textit{Chandra} space telescope. Employing different techniques -- velocity distribution of galaxies, weak gravitational lensing, and X-ray spatially resolved spectroscopy -- we derive mass and velocity dispersion estimates from each of them. All estimates agree well with each other, within a 68% confidence level, indicating a velocity dispersion of 1000 -- 1250 \kms. The projected mass distributions obtained through weak-lensing and X-ray emission are strikingly similar, having nearly circular geometry. We suggest that Abell 586 is probably a truly relaxed cluster, whose last major merger occurred more than $\sim 4$ Gyr agoComment: ApJ accepted, 20 pages, 11 figures; Figure 1 fixe

Radial Temperature Profiles of X-Ray--Emitting Gas Within Clusters of Galaxies

Previous analyses of ASCA data of clusters of galaxies have found conflicting results regarding the slope of the temperature profile of the hot X-ray gas within clusters, mainly because of the large, energy-dependent point spread function (PSF) of the ASCA mirrors. We present a summary of all ASCA-determined cluster temperature profiles found in the literature, and find a discrepancy in the radial temperature trend of clusters based on which PSF-correction routine is used. This uncertainty in the cluster temperature profile in turn can lead to large uncertainties in the amount of dark matter in clusters. In this study, we have used ROSAT PSPC data to obtain independent relative temperature profiles for 26 clusters, most of which have had their temperature profiles determined by ASCA. Our aim is not to measure the actual temperature values of the clusters, but to use X-ray color profiles to search for a hardening or softening of the spectra with radius for comparison to ASCA-derived profiles. The radial color profiles indicate that outside of the cooling flow region, the temperature profiles of clusters are in general constant. Within 35% of the virial radius, we find a temperature drop of 20% at 10 keV and 12% at 5 keV can be ruled out at the 99% confidence level. A subsample of non-cooling flow clusters shows that the condition of isothermality applies at very small radii too, although cooling gas complicates this determination in the cooling flow subsample. The colors predicted from the temperature profiles of a series of hydrodynamical cluster simulations match the data very well, although they cannot be used to discriminate among different cosmologies. An additional result is that the color profiles show evidence for a central peak in metallicity in low temperature clusters.Comment: 39 pages, 15 embedded Postscript figures, uses aaspp4.sty, accepted for publication in Astrophysical Journa