Inclusive cross section and double helicity asymmetry for \pi^0 production in p+p collisions at sqrt(s)=200 GeV: Implications for the polarized gluon distribution in the proton

The PHENIX experiment presents results from the RHIC 2005 run with polarized proton collisions at sqrt(s)=200 GeV, for inclusive \pi^0 production at mid-rapidity. Unpolarized cross section results are given for transverse momenta p_T=0.5 to 20 GeV/c, extending the range of published data to both lower and higher p_T. The cross section is described well for p_T < 1 GeV/c by an exponential in p_T, and, for p_T > 2 GeV/c, by perturbative QCD. Double helicity asymmetries A_LL are presented based on a factor of five improvement in uncertainties as compared to previously published results, due to both an improved beam polarization of 50%, and to higher integrated luminosity. These measurements are sensitive to the gluon polarization in the proton, and exclude maximal values for the gluon polarization.Comment: 375 authors, 7 pages, 3 figures. Submitted to Phys. Rev. D, Rapid Communications. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Measurement of Bottom versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p+p Collisions at sqrt(s)=200 GeV

The momentum distribution of electrons from semi-leptonic decays of charm and bottom for mid-rapidity |y|<0.35 in p+p collisions at sqrt(s)=200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) over the transverse momentum range 2 < p_T < 7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D^bar --> e^{+/-} K^{-/+} X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in p_T. A fixed-order-plus-next-to-leading-log (FONLL) perturbative quantum chromodynamics (pQCD) calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is \sigma_{b\b^bar}= 3.2 ^{+1.2}_{-1.1}(stat) ^{+1.4}_{-1.3}(syst) micro b.Comment: 432 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration

Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (p_T), elliptic flow, two-particle correlations, non-statistical fluctuations, and suppression of particle production at high p_T. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted to Nuclear Physics A as a regular article; v3 has minor changes in response to referee comments. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

System Size and Energy Dependence of Jet-Induced Hadron Pair Correlation Shapes in Cu+Cu and Au+Au Collisions at sqrt(s_NN) = 200 and 62.4 GeV

We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from {dijets} in Cu+Cu and Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from \Delta\phi=\pi in central and semi-central collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models.Comment: 464 authors from 60 institutions, 6 pages, 3 figures, 2 tables. Submitted to Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

A Genetic Algorithm for Assembly Sequence Planning

This work presents a genetic algorithm for assembly sequence planning. This problem is more difficult than other sequencing problems that have already been tackled with success using these techniques, such as the classic Traveling Salesperson Problem (TSP) or the Job Shop Scheduling Problem (JSSP). It not only involves the arranging of tasks, as in those problems, but also the selection of them from a set of alternative operations. Two families of genetic operators have been used for searching the whole solution space. The first includes operators that search for new sequences locally in a predetermined assembly plan, that of parent chromosomes. The other family of operators introduces new tasks in the solution, replacing others to maintain the validity of chromosomes, and it is intended to search for sequences in other assembly plans. Furthermore, some problem-based heuristics have been used for generating the individuals in the population

Improved Measurement of Double Helicity Asymmetry in Inclusive Midrapidity pi^0 Production for Polarized p+p Collisions at sqrt(s)=200 GeV

We present an improved measurement of the double helicity asymmetry for pi^0 production in polarized proton-proton scattering at sqrt(s) = 200 GeV employing the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The improvements to our previous measurement come from two main factors: Inclusion of a new data set from the 2004 RHIC run with higher beam polarizations than the earlier run and a recalibration of the beam polarization measurements, which resulted in reduced uncertainties and increased beam polarizations. The results are compared to a Next to Leading Order (NLO) perturbative Quantum Chromodynamics (pQCD) calculation with a range of polarized gluon distributions.Comment: 389 authors, 4 pages, 2 tables, 1 figure. Submitted to Phys. Rev. D, Rapid Communications. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Genetic characterization of cassava (Manihot esculenta) landraces in Brazil assessed with simple sequence repeats

Based on nine microsatellite loci, the aim of this study was to appraise the genetic diversity of 42 cassava (Manihot esculenta) landraces from selected regions in Brazil, and examine how this variety is distributed according to origin in several municipalities in the states of Minas Gerais, São Paulo, Mato Grosso do Sul, Amazonas and Mato Grosso. High diversity values were found among the five above-mentioned regions, with 3.3 alleles per locus on an average, a high percentage of polymorphic loci varying from 88.8% to 100%, an average of 0.265 for observed heterozygosity and 0.570 for gene diversity. Most genetic diversity was concentrated within the regions themselves (HS = 0.52). Cluster analysis and principal component based scatter plotting showed greater similarity among landraces from São Paulo, Mato Grosso do Sul and Amazonas, whereas those from Minas Gerais were clustered into a sub-group within this group. The plants from Mato Grosso, mostly collected in the municipality of General Carneiro, provided the highest differentiation. The migration of human populations is one among the possible reasons for this closer resemblance or greater disparity among plants from the various regions

Componentes de produção e morfologia de raízes de mandioca sob diferentes preparos do solo

In order to evaluate the effect of minimum tillage, conventional tillage and no-tillage on yield components and the morphology of roots of sweet cassava cv. IAC 576-70 was conducted a field experiment in randomized blocks design with split plot with six replications. The different tillages: minimum tillage, conventional tillage and no-tillage plots were considered the plots and the evaluation time, in days after planting, were considered the subplots. In this experiment were mensured the number, length, diameter, fresh and dry weight, dry matter content and morphological characteristics of cassava roots at different sampling times. From the results of these assessments it was concluded that the soil tillage influence root diameter, fresh and dry weight, in the early dormancy phase and new period of vegetative growth, the soil tillage did not influence the chronological definition of the yield component as well as the morphology of cassava roots and the yield components of sweet cassava cv. IAC 576-70 are defined in the following order, number of roots, length, diameter, dry matter content, fresh and dry weight.Com o objetivo de avaliar o efeito de cultivo mínimo, plantio convencional e plantio direto sobre os componentes de produção e a morfologia das raízes tuberosas de mandioca da cultivar de mesa IAC 576-70, conduziu-se este experimento a campo em delineamento experimental de blocos ao acaso, com parcelas subdivididas com seis repetições. Os preparos do solo, cultivo mínimo, preparo convencional e plantio direto, foram consideradas as parcelas e as épocas de avaliação, em dias após o plantio, foram consideras as subparcelas. Neste experimento foram avaliados o número, comprimento, diâmetro, massas fresca e seca, teor de massa seca e as características morfológicas das raízes de mandioca em diferentes épocas de avaliação. A partir dos resultados dessas avaliações foi possível concluir que o preparo de solo influencia no diâmetro das raízes, nas massas fresca e seca no início das fases de repouso fisiológico e retomada do novo período vegetativo; que o preparo de solo não influencia a definição cronológica dos componentes de produção nem a morfologia de raízes de mandioca; e que os componentes da produção de raízes são definidos no tempo na seguinte ordem: número de raízes, comprimento, diâmetro, teor de massa seca, massas fresca e seca.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agrárias Departamento de Produção e Melhoramento VegetalUNESP FCA Instituto de BiociênciasUNESP FCA Departamento de HorticulturaInstituto Agronômico Centro de HorticulturaUniversidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agrárias Departamento de Produção e Melhoramento VegetalUNESP FCA Instituto de BiociênciasUNESP FCA Departamento de Horticultur