Measurement of B-d mixing using opposite-side flavor tagging

We report on a measurement of the B-d(0) mixing frequency and the calibration of an opposite-side flavor tagger in the D0 experiment. Various properties associated with the b quark on the opposite side of the reconstructed B meson are combined using a likelihood-ratio method into a single variable with enhanced tagging power. Its performance is tested with data, using a large sample of reconstructed semileptonic B ->mu(DX)-X-0 and B ->mu(DX)-X-* decays, corresponding to an integrated luminosity of approximately 1 fb(-1). The events are divided into groups depending on the value of the combined tagging variable, and an independent analysis is performed in each group. Combining the results of these analyses, the overall effective tagging power is found to be epsilon D-2=(2.48 +/- 0.21(-0.06)(+0.08))%. The measured B-d(0) mixing frequency Delta m(d)=0.506 +/- 0.020(stat)+/- 0.016(syst) ps(-1) is in good agreement with the world average value.

Study of the decay B-s(0)->(DsDs(*))-D-(*)

We report a study of the decay B-s(0)->(DsDs(*))-D-(*) using a data sample corresponding to 1.3 fb(-1) of integrated luminosity collected by the D0 experiment in 2002-2006 during run II of the Fermilab Tevatron collider. One D-s((*)) meson was partially reconstructed in the decay D-s ->phi mu nu, and the other D-s((*)) meson was identified using the decay D-s ->phi pi where no attempt was made to distinguish D-s and D-s(*) states. For the branching fraction Br(B-s(0)->(DsDs(*))-D-(*)) we obtain a 90% C.L. range [0.002,0.080] and central value 0.039(-0.017)(+0.019)(stat)(-0.015)(+0.016)(syst). This was subsequently used to make the most precise estimate of the width difference Delta Gamma(CP)(s) in the B-s(0)-(B)over bar(s)(0) system: Delta Gamma(CP)(s)/Gamma(s)=0.079(-0.035)(+0.038)(stat)(-0.030)(+0.031)(syst).

Measurement of semileptonic branching fractions of B mesons to narrow D-** states - art. no. 1711803

Using the data accumulated in 2002-2004 with the D0 detector in proton-antiproton collisions at the Fermilab Tevatron collider with a center-of-mass energy of 1.96 TeV, the branching fractions of the decays B ->(D) over bar (0)(1)(2420)mu(+)nu(mu)X and B ->(D) over bar (*0)(2)(2460)mu(+)nu(mu)X and their ratio have been measured: B (b) over bar -> B)xB(B -> (D) over bar (0)(1)mu(+)nu(mu)X)xB((D) over bar (0)(1)-> D(*-)pi(+))=[0.087 +/- 0.007(stat)+/- 0.014(syst)]%; B((b) over bar -> B)xB(B ->(D) over bar (*0)(2)mu(+)nu(mu)X)xB((D) over bar (*0)(2)-> D(*-)pi(+))=[0.035 +/- 0.007(stat)+/- 0.008(syst)]% and [B(B ->(D) over bar (*0)(2)mu(+)nu(mu)X)xB((D) over bar (*0)(2)-> D(*-)pi(+))]/[B(B ->(D) over bar (0)(1)mu(+)nu(mu)X)xB((D) over bar (0)(1)-> D(*-)pi(+))]=0.39 +/- 0.09(stat)+/- 0.12(syst), where the charge conjugated states are always implied.

Evidence for the Decay B-s(0)->(DsDs(*))-D-(*) and a Measurement of Delta Gamma(CP)(s)/Gamma(s)

We search for the semi-inclusive process B-s(0)->(DsDs(*))-D-(*) using 2.8 fb(-1) of pp collisions at s=1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe 26.6 +/- 8.4 signal events with a significance above background of 3.2 standard deviations yielding a branching ratio of B(B-s(0)->(DsDs(*))-D-(*))=0.035 +/- 0.010(stat.)+/- 0.011(syst.). Under certain theoretical assumptions, these double-charm final states saturate CP-even eigenstates in the B-s(0) decays resulting in a width difference of Delta Gamma(CP)(s)/Gamma(s)=0.072 +/- 0.021(stat.)+/- 0.022(syst.).

Search for CP violation in B-s(0) -> mu(+) D-s(-) X decays in p(p)over-bar collisions at root s=1.96 TeV

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cold Nuclear Matter Effects on J/psi Yields as a Function of Rapidity and Nuclear Geometry in d plus A Collisions at root S(NN)=200 GeV

We present measurements of J/psi yields in d + Au collisions at root S(NN) = 200 GeV recorded by the PHENIX experiment and compare them with yields in p + p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J/psi rapidity (-2.2 < y < 2.4) with high statistical precision and are compared with two theoretical models: one with nuclear shadowing combined with final state breakup and one with coherent gluon saturation effects. In order to remove model dependent systematic uncertainties we also compare the data to a simple geometric model. The forward rapidity data are inconsistent with nuclear modifications that are linear or exponential in the density weighted longitudinal thickness, such as those from the final state breakup of the bound state.

Nuclear modification factors of phi mesons in d plus Au, Cu plus Cu, and Au plus Au collisions at root s(NN)=200 GeV

The PHENIX experiment at the Relativistic Heavy Ion Collider has performed systematic measurements of phi meson production in the K(+)K(-) decay channel at midrapidity in p + p, d + Au, Cu + Cu, and Au + Au collisions at root s(NN) = 200 GeV. Results are presented on the phi invariant yield and the nuclear modification factor R(AA) for Au + Au and Cu + Cu, and R(dA) for d + Au collisions, studied as a function of transverse momentum (1 < p(T) < 7 GeV/c) and centrality. In central and midcentral Au + Au collisions, the R(AA) of phi exhibits a suppression relative to expectations from binary scaled p + p results. The amount of suppression is smaller than that of the pi(0) and the. in the intermediate p(T) range (2-5 GeV/c), whereas, at higher p(T), the phi, pi(0), and. show similar suppression. The baryon (proton and antiproton) excess observed in central Au + Au collisions at intermediate p(T) is not observed for the phi meson despite the similar masses of the proton and the phi. This suggests that the excess is linked to the number of valence quarks in the hadron rather than its mass. The difference gradually disappears with decreasing centrality, and, for peripheral collisions, the R(AA) values for both particle species are consistent with binary scaling. Cu + Cu collisions show the same yield and suppression as Au + Au collisions for the same number of N(part). The R(dA) of phi shows no evidence for cold nuclear effects within uncertainties.

Azimuthal di-hadron correlations in d plus Au and Au plus Au collisions at root s(NN)=200 GeV measured at the STAR detector

Yields, correlation shapes, and mean transverse momenta p(T) of charged particles associated with intermediate-to high-p(T) trigger particles (2.5 < p(T) < 10 GeV/c) in d + Au and Au + Au collisions at root s(NN) = 200 GeV are presented. For associated particles at higher p(T) greater than or similar to 2.5 GeV/c, narrow correlation peaks are seen in d + Au and Au + Au, indicating that the main production mechanism is jet fragmentation. At lower associated particle pT < 2 GeV/c, a large enhancement of the near- (Delta phi similar to 0) and away-side (Delta phi similar to pi) associated yields is found, together with a strong broadening of the away-side azimuthal distributions in Au + Au collisions compared to d + Au measurements, suggesting that other particle production mechanisms play a role. This is further supported by the observed significant softening of the away-side associated particle yield distribution at Delta phi similar to pi in central Au + Au collisions.

Balance functions from Au+Au, d+Au, and p+p collisions at root s(NN)=200 GeV

Balance functions have been measured for charged-particle pairs, identified charged-pion pairs, and identified charged-kaon pairs in Au + Au, d + Au, and p + p collisions at root s(NN) = 200 GeV at the Relativistic Heavy Ion Collider using the STAR detector. These balance functions are presented in terms of relative pseudorapidity, Delta eta, relative rapidity, Delta y, relative azimuthal angle, Delta phi, and invariant relative momentum, q(inv). For charged-particle pairs, the width of the balance function in terms of Delta eta scales smoothly with the number of participating nucleons, while HIJING and UrQMD model calculations show no dependence on centrality or system size. For charged-particle and charged-pion pairs, the balance functions widths in terms of Delta eta and Delta y are narrower in central Au + Au collisions than in peripheral collisions. The width for central collisions is consistent with thermal blast-wave models where the balancing charges are highly correlated in coordinate space at breakup. This strong correlation might be explained by either delayed hadronization or limited diffusion during the reaction. Furthermore, the narrowing trend is consistent with the lower kinetic temperatures inherent to more central collisions. In contrast, the width of the balance function for charged-kaon pairs in terms of Delta y shows little centrality dependence, which may signal a different production mechanism for kaons. The widths of the balance functions for charged pions and kaons in terms of q(inv) narrow in central collisions compared to peripheral collisions, which may be driven by the change in the kinetic temperature.

Inclusive pi(0), eta, and direct photon production at high transverse momentum in p plus p and d plus Au collisions at root s(NN)=200 GeV

We report a measurement of high-p(T) inclusive pi(0), eta, and direct photon production in p + p and d + Au collisions at root s(NN) = 200 GeV at midrapidity (0 < eta < 1). Photons from the decay pi(0) -> gamma gamma were detected in the barrel electromagnetic calorimeter of the STAR experiment at the Relativistic Heavy Ion Collider. The eta -> gamma gamma decay was also observed and constituted the first eta measurement by STAR. The first direct photon cross-section measurement by STAR is also presented; the signal was extracted statistically by subtracting the pi(0), eta, and omega(782) decay background from the inclusive photon distribution observed in the calorimeter. The analysis is described in detail, and the results are found to be in good agreement with earlier measurements and with next-to-leading-order perturbative QCD calculations.

ANÁLISE DE CRESCIMENTO DE MUDAS DE JACAREÚBA (Calophyllum angulare A. C. SMITH - GUTTIFERAE) CULTIVADAS EM CONDIÇÕES DE VIVEIRO.

O presente trabalho, conduzido no viveiro da Reserva Florestal Adolfo Ducke, Amazonas, Brasil, teve como objetivo comparar quatro níveis de sombreamento no crescimento de mudas de jacareúba (Calophyllum angulare). Foram utilizados os níveis de sombreamento 30,50 e 70%, obtidos com telas de poliolefinas de cor preta, e o nível 0% a pleno sol. A análise de crescimento foi feita imediatamente após a transferência das mudas para os canteiros e mensalmente durante 5 meses. Foram obtidos os seguintes resultados: a) Os maiores valores de altura; diâmetro do colo-e área foliar foram obtidos nas mudas cultivadas sob 70% de sombreamento aos 150 dias de permanência no viveiro; b)Ocorreu uma tend&#234;ncia de decr&#233;scimo nos valores de taxa de crescimento relativo foliar e de razão de área foliar em decorrência do período de permanência das mudas no viveiro; c) A taxa de crescimento relativo foliar não foi influenciada pelos níveis de sombreamento; d) As mudas cultivadas sob 70% apresentaram valores de taxa de crescimento relativo da parte a&#233;rea que indicam uma melhor adaptação a essa condição; com relação a taxa de crescimento relativo das raízes, os níveis de sombreamento mais favoráveis foram 0 e 50%; e) O efeito da aclimatação sobre as mudas cultivadas sob 70%, provocou uma diminuição temporária nas taxas de crescimento relativo da parte a&#233;rea c crescimento relativo total, entre os períodos de 30 a 60 dias.

Estudi microgenètic sobre el desenvolupament del coneixement lletrat en alumnes de Primà ria en relació amb textosmodel d'una base de dades Web: influència del suport digital i del format de presentació

Aquest projecte representa una recerca en les classes basat en l'eficàcia de la combinació entre activitats de lectura i d'escriptura, textos i tecnologia. Presenta un currículum bé dissenyat que ofereix material als professors per a planificar la instrucció en primària i en pre-escolar. Els materials són una selecció de textos considerats com uns mediadors de la instrucció. L’estudi proporciona un model preliminar per a un currículum basat en textos que ajuden en la lectura i escriptura i en les habilitats inicials. Les lectures són llibres tipus àlbum. Dues dècades en el camp dels llibres infantils, il•lustradors, autors, editors han prestat una major atenció a les maneres del procés d'adquisició de la lectura i de l'escriptura. Aquest estudi representa un pas per a incloure aquest tipus de materials de lectura. Tres característiques de text s'han identificat: a) el contingut lingüístic a nivell de la paraula, i a nivell de l'estructura del text (repeticions dels patrons sintàctics i textuals); b) la diversitat de gènere dels llibres (llibres de narració i d'informació); i c) el control de la càrrega cognitiva (densitat de paraules, repetició i predicció del contingut i relació il•lustració-text). Els participants en aquest estudi eren 25 nens de primer curs i 23 nens pre-escolars i els seus professors (CEIP Lavinia de Barcelona). L'escola va ser seleccionada per la seva disposició a l'ús de tecnologies i els seus interessos de participar en aquest projecte experimental. Durant l'any 2007-08 van desenvolupar aquests textos, les activitats i el programa de tecnologia (Veure www.princepsiprinceses.blogspot.com, i www.conills.blogspot.com). Els efectes de la qualitat instruccional, de la selecció de textos i de l'ús de la tecnologia s'han d'observar en les diferències en les pràctiques de les professores, en les habilitats dels nens i en l'ús de tecnologies en les sales de classe.

Decrease in the prevalence of hepatitis B and a low prevalence of hepatitis C virus infections in the general population of the Seychelles.

A serological survey of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections was carried out on a random sex- and age-stratified sample of 1006 individuals aged 25-64 years in the Seychelles islands. Anti-HBc and anti-HCV antibodies were detected using commercially available enzyme-linked immunosorbent assays (ELISA), followed by a Western blot assay in the case of a positive result for anti-HCV. The age-adjusted seroprevalence of anti-HBc antibodies was 8.0% (95% CI: 6.5-9.9%) and the percentage prevalence among males/females increased from 7.0/3.1 to 19.1/13.4 in the age groups 25-34 to 55-64 years, respectively. Two men and three women were positive for anti-HCV antibodies, with an age-adjusted seroprevalence of 0.34% (95% CI: 0.1-0.8%). Two out of these five subjects who were positive for anti-HCV also had anti-HBc antibodies. The seroprevalence of anti-HBc was significantly higher in unskilled workers, persons with low education, and heavy drinkers. The age-specific seroprevalence of anti-HBc in this population-based survey, which was conducted in 1994, was approximately three times lower than in a previous patient-based survey carried out in 1979. Although there are methodological differences between the two surveys, it is likely that the substantial decrease in anti-HBc prevalence during the last 15 years may be due to significant socioeconomic development and the systematic screening of blood donors since 1981. Because hepatitis C virus infections are serious and the cost of treatment is high, the fact that the prevalence of anti-HCV antibodies is at present low should not be an argument for not screening blood donors for anti-HCV and eliminating those who are positive.

Exclusion of pulmonary embolism using C-reactive protein and D-dimer. A prospective comparison.

Our goal was to evaluate the diagnostic utility of C-reactive protein (CRP) alone or combined with clinical probability assessment in patients with suspected pulmonary embolism (PE), and to compare its performance to a D-dimer assay. We conducted a prospective study in which we performed a common immuno-turbidimetric CRP test and a rapid enzyme-linked immunosorbent assay (ELISA) D-dimer test in 259 consecutive outpatients with suspected PE at the emergency department of a teaching hospital. We assessed clinical probability of PE by a validated prediction rule overridden by clinical judgment. Patients with D-dimer levels &gt; or = 500 microg/l underwent a work-up consisting of lower-limb venous ultrasound, spiral computerized tomography, ventilation-perfusion scan, or pulmonary angiography. Patients were followed up for three months. Seventy-seven (30%) of the patients had PE. The CRP alone had a sensitivity of 84% (95% confidence interval [CI).: 74 to 92%) and a negative predictive value (NPV) of 87% (95% CI: 78 to 93%) at a cutpoint of 5 mg/l. Overall, 61 (24%) patients with a low clinical probability of PE had a CRP &lt; 5 mg/l. Due to the low prevalence of PE (9%) in this subgroup, the NPV increased to 97% (95% CI: 89 to 100%). The D-dimer (cutpoint 500 micro g/l) showed a sensitivity of 100% (95% CI: 95 to 100%) and a NPV of 100% (95% CI: 94 to 100%) irrespective of clinical probability and accurately rule out PE in 56 (22%) patients. Standard CRP tests alone or combined with clinical probability assessment cannot safely exclude PE.

La Inclusió del portafolis com a estratègia metodològica d'aprenentatge de l'estudiant en el marc europeu d'educació superior

Aquest article presenta els resultats del procés d’implementació del portafoli a primer curs dels estudis d’infermeria, en l’assignatura d’estructura i funcionament del cos humà. La justificació del recurs didàctic s’identifica en el paradigma del marc europeu d’educació superior, el qual es basa en l’aprenentatge responsable i constant de l’estudiant. El principal objectiu del portafoli es centra en guiar als estudiants en la seva activitat d’aprenentatge, afavorint l’autopercepció del procés, fomentar la creativitat per poder assolir els objectius i continguts des de la seva perspectiva i coneixement emprant una visió crítica individual. Aquest marc, facilita l’adquisició competencial i la construcció de l’aprenentatge significatiu aconseguint aproximar el coneixement a la clínica assistencial real. El resultat final permetrà aconseguir les estratègies determinants del conegut aprendre a aprendre d’una forma significativa. Durant el procés d’implementació del portafoli s’ha avaluat una mostra de 180 estudiants, els quals s’han repartit en 2 grups, 130 han elaborat el portafoli i 50 no l’han elaborat. Es realitza una avaluació quantitativa dels resultats acadèmics de l’estudiant i qualitativa on es recullen els indicis del resultat de la implementació de l’instrument a partir del registre dels estudiants i professors. Els resultats configuren els punts forts i febles que representa l’instrument. Amb l’anàlisi quantitativa, s’observa que el 83% d’estudiants que lliuren el portafoli aproven a la primera o segona convocatòria amb una nota mitjana de 6.63/10. Mentre que, el 27% d’estudiants que no elaboren el portafoli aproven l’assignatura en primera o segona convocatòria amb una nota mitjana de 5,03/10. Amb l’anàlisi qualitativa s’observa que el recurs ofereix una informació àmplia i detallada de l’instrument didàctic com a eina d’ajuda i suport en el procés d’aprenentatge. Per altra banda, es detecta que suposa una sobrecàrrega per l’estudiant. És un producte personalitzat i individual en què l’estudiant assoleix les competències, fomenta la creativitat. En virtut dels resultats i amb l’anàlisi estadística es confirma que l’estratègia metodològica és un element clau per l’adquisició i consolidació del coneixement que motiva a l’autodisciplina, a l’autoaprenentatge i a l’autoavaluació, percebre l’avanç formatiu i ajustar l’esforç en relació al resultat acadèmic