Directed Flow of Identified Particles in Au plus Au Collisions at root S-NN=200 GeV at RHIC

STAR's measurements of directed flow (v(1)) around midrapidity for pi(+/-), K-+/-, K-S(0), p, and (p) over bar in Au + Au collisions at root s(NN) = 200 GeV are presented. A negative v(1) (y) slope is observed for most of produced particles (pi(+/-), K-+/-, K-S(0), p, and (p) over bar). In 5%-30% central collisions, a sizable difference is present between the v(1)(y) slope of protons and antiprotons, with the former being consistent with zero within errors. The v(1) excitation function is presented. Comparisons to model calculations (RQMD, UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. For those models which have calculations of v(1) for both pions and protons, none of them can describe v(1()y) forpions and protons simultaneously. The hydrodynamics model with a tilted source as currently implemented cannot explain the centrality dependence of the difference between the v(1)(y) slopes of protons and antiprotons.

Measurements of atmospheric neutrinos and antineutrinos in the MINOS far detector

This paper reports measurements of atmospheric neutrino and antineutrino interactions in the MINOS Far Detector, based on 2553 live-days (37.9 kton-years) of data. A total of 2072 candidate events are observed. These are separated into 905 contained-vertex muons and 466 neutrino-induced rock-muons, both produced by charged-current nu(mu) and (nu) over bar (mu) interactions, and 701 contained-vertex showers, composed mainly of charged-current nu(e) and (nu) over bar (e) interactions and neutral-current interactions. The curvature of muon tracks in the magnetic field of the MINOS Far Detector is used to select separate samples of nu(mu) and (nu) over bar (mu) events. The observed ratio of (nu) over bar (mu) to v(mu) events is compared with the Monte Carlo ( MC) simulation, giving a double ratio of R((nu) over bar/nu)data/R(nu) over bar/nu MC = 1.03 +/- 0.08(stat) +/- 0.08(syst). The v(mu) and (nu) over bar (mu) data are separated into bins of L/E resolution, based on the reconstructed energy and direction of each event, and a maximum likelihood fit to the observed L/E distributions is used to determine the atmospheric neutrino oscillation parameters. This fit returns 90% confidence limits of |Delta m(2)| = (1.9 +/- 0.4) x 10(-3) eV(2) and sin(2)2 theta > 0.86. The fit is extended to incorporate separate nu(mu) and (nu) over bar mu oscillation parameters, returning 90% confidence limits of |Delta m(2)| - |Delta(m) over bar (2)| = 0.6(-0.8)(+2.4) x 10(-3) eV(2) on the difference between the squared-mass splittings for neutrinos and antineutrinos.

Benthic foraminiferal distribution on the southeastern Brazilian shelf and upper slope

Foraminiferal data were obtained from 66 samples of box cores on the southeastern Brazilian upper margin (between 23.8A degrees-25.9A degrees S and 42.8A degrees-46.13A degrees W) to evaluate the benthic foraminiferal fauna distribution and its relation to some selected abiotic parameters. We focused on areas with different primary production regimes on the southern Brazilian margin, which is generally considered as an oligotrophic region. The total density (D), richness (R), mean diversity (H) over bar`, average living depth (ALD(X) ) and percentages of specimens of different microhabitats (epifauna, shallow infauna, intermediate infauna and deep infauna) were analyzed. The dominant species identified were Uvigerina spp., Globocassidulina subglobosa, Bulimina marginata, Adercotryma wrighti, Islandiella norcrossi, Rhizammina spp. and Brizalina sp.. We also established a set of mathematical functions for analyzing the vertical foraminiferal distribution patterns, providing a quantitative tool that allows correlating the microfaunal density distributions with abiotic factors. In general, the cores that fit with pure exponential decaying functions were related to the oligotrophic conditions prevalent on the Brazilian margin and to the flow of the Brazilian Current (BC). Different foraminiferal responses were identified in cores located in higher productivity zones, such as the northern and the southern region of the study area, where high percentages of infauna were encountered in these cores, and the functions used to fit these profiles differ appreciably from a pure exponential function, as a response of the significant living fauna in deeper layers of the sediment. One of the main factors supporting the different foraminiferal assemblage responses may be related to the differences in primary productivity of the water column and, consequently, in the estimated carbon flux to the sea floor. Nevertheless, also bottom water velocities, substrate type and water depth need to be considered.

Optimization of x-ray spectra in digital mammography through Monte Carlo simulations

In this work, a Monte Carlo code was used to investigate the performance of different x-ray spectra in digital mammography, through a figure of merit (FOM), defined as FOM = CNR2/(D) over bar (g), with CNR being the contrast-to-noise ratio in image and (D) over bar (g) being the average glandular dose. The FOM was studied for breasts with different thicknesses t (2 cm <= t <= 8 cm) and glandular contents (25%, 50% and 75% glandularity). The anode/filter combinations evaluated were those traditionally employed in mammography (Mo/Mo, Mo/Rh, Rh/Rh), and a W anode combined with Al or K-edge filters (Zr, Mo, Rh, Pd, Ag, Cd, Sn), for tube potentials between 22 and 34 kVp. Results show that the W anode combined with K-edge filters provides higher values of FOM for all breast thicknesses investigated. Nevertheless, the most suitable filter and tube potential depend on the breast thickness, and for t >= 6 cm, they also depend on breast glandularity. Particularly for thick and dense breasts, a W anode combined with K-edge filters can greatly improve the digital technique, with the values of FOM up to 200% greater than that obtained with the anode/filter combinations and tube potentials traditionally employed in mammography. For breasts with t < 4 cm, a general good performance was obtained with the W anode combined with 60 mu m of the Mo filter at 24-25 kVp, while 60 mu m of the Pd filter provided a general good performance at 24-26 kVp for t = 4 cm, and at 28-30 and 29-31 kVp for t = 6 and 8 cm, respectively.

Wh plus missing-E-T signature from gaugino pair production at the LHC

In SUSY models with heavy squarks and gaugino mass unification, the gaugino pair production reaction pp -> (W) over tilde (+/-)(1)(Z) over tilde (2) dominates gluino pair production for m (g) over tilde less than or similar to 1 TeV at LHC with root s = 14 TeV (LHC14). For this mass range, the two-body decays (W) over tilde (1) -> W (Z) over tilde (1) and (Z) over tilde (2) -> h (Z) over tilde (1) are expected to dominate the chargino and neutralino branching fractions. By searching for lb (b) over tilde + is not an element of(T) events from (W) over tilde (+/-)(1)Z(2) production, we show that LHC14 with 100 fb(-1) of integrated luminosity becomes sensitive to chargino masses in the range m((W) over tilde1) similar to 450-550 GeV corresponding to m (g) over tilde similar to 1.5-2 TeV in models with gaugino mass unification. For 10(3) fb(-1), LHC14 is sensitive to the Wh channel for m((W) over tilde1) similar to 300-800 GeV, corresponding to m (g) over tilde similar to 1-2.8 TeV, which is comparable to the reach for gluino pair production followed by cascade decays. The Wh + is not an element of(T) search channel opens up a new complementary avenue for SUSY searches at LHC, and serves to point to SUSYas the origin of any new physics discovered via multijet and multilepton + is not an element of(T) channels.

Comparison of microsatellites and isozymes in genetic diversity studies of Oryza glumaepatula (Poaceae) populations

The study of the genetic structure of wild plant populations is essential for their management and conservation. Several DNA markers have been used in such studies, as well as isozyme markers. In order to provide a better comprehension of the results obtained and a comparison between markers which will help choose tools for future studies in natural populations of Oryza glumaepatula, a predominantly autogamous species, this study used both isozymes and microsatellites to assess the genetic diversity and genetic structure of 13 populations, pointing to similarities and divergences of each marker, and evaluating the relative importance of the results for studies of population genetics and conservation. A bulk sample for each population was obtained, by sampling two to three seeds of each plant, up to a set of 50 seeds. Amplified products of eight SSR loci were electrophoresed on non-denaturing polyacrylamide gels, and the fragments were visualized using silver staining procedure. Isozyme analyses were conducted in polyacrylamide gels, under a discontinuous system, using six enzymatic loci. SSR loci showed higher mean levels of genetic diversity (A=2.83, p=0.71, A(P)=3.17, H-o=0.081, H-e=0.351) than isozyme loci (A=1.20, p=0.20, A(P)=1.38, H-o=0.006, H-e=0.056). Interpopulation genetic differentiation detected by SSR loci (R-ST=0.631, equivalent to F-ST=0.533) was lower than that obtained with isozymes (F-ST=0.772). However, both markers showed high deviation from Hardy-Weinberg expectations (F-IS=0.744 and 0.899, respectively for SSR and isozymes). The mean apparent outcrossing rate for SSR ((t) over bar (a)=0.14) was higher than that obtained using isozymes ((t) over bar (a)=0.043), although both markers detected lower levels of outcrossing in Amazonia compared to the Pantanal. The migrant number estimation was also higher for SSR (Nm=0.219) than isozymes (Nm=0.074), although a small number for both markers was expected due to the mode of reproduction of this species, defined as mixed with predominance of self fertilization. No correlation was obtained between genetic and geographic distances with SSR, but a positive correlation was found between genetic and geographic distances with isozymes. We conclude that these markers are divergent in detecting genetic diversity parameters in O. glumaepatula and that microsatellites are powerful for detecting information at the intra-population level, while isozymes are more powerful for inter-population diversity, since clustering of populations agreed with the expectations based on the geographic distribution of the populations using this marker. Rev. Biol. Trop. 60 (4): 1463-1478. Epub 2012 December 01.

A Single Statistic for Monitoring the Covariance Matrix of Bivariate Processes

In this article, we present a new control chart for monitoring the covariance matrix in a bivariate process. In this method, n observations of the two variables were considered as if they came from a single variable (as a sample of 2n observations), and a sample variance was calculated. This statistic was used to build a new control chart specifically as a VMIX chart. The performance of the new control chart was compared with its main competitors: the generalized sampled variance chart, the likelihood ratio test, Nagao's test, probability integral transformation (v(t)), and the recently proposed VMAX chart. Among these statistics, only the VMAX chart was competitive with the VMIX chart. For shifts in both variances, the VMIX chart outperformed VMAX; however, VMAX showed better performance for large shifts (higher than 10%) in one variance.

Bulk neutrinos as an alternative cause of the gallium and reactor anti-neutrino anomalies

We consider an alternative explanation for the deficit of nu(e) in Ga solar neutrino calibration experiments and of the (nu) over bar (e) in short-baseline reactor experiments by a model where neutrinos can oscillate into sterile Kaluza-Klein modes that can propagate in compactified submicrometer flat extra dimensions. We have analyzed the results of the gallium radioactive source experiments and 19 reactor experiments with baseline shorter than 100 m, and showed that these data can be fit into this scenario. The values of the lightest neutrino mass and of the size of the largest extra dimension that are compatible with these experiments are mostly not excluded by other neutrino oscillation experiments.