Realidade X Fantasia:: Sua influência no raciocínio dedutivo

Many studies have shown the importance of mode ofpresentation in tasks aimed at evaluating cognitive performance.In three experiments concerning the understanding of syllogisticproblems whose content runs counter to subjects' practical worldknowledge, we examined the hypothesis that the presence of thetoys in a make-believe condition, would significantly improve children'sperformance, since encoding of the premisses would be facilitated.Experiments I, II and III showed that, as in the study of Dias& Harris (submited), children's performance was significantly betterwhen the premisses were presented in a make-believe play moderather than in the standard verbal mode. The make-believe contextof play is what facilitates children's reasoning, when the premissesof the problems run counter to their experience.A importância do modo de apresentação das tarefas para avaliar o desempenho cognitivo tem sido enfatizada em muitos estudos. Em três experimentos sobre a compreensão de problemas silogísticos com conteúdos contrários à experiência do dia-a-dia das crianças analisou-se até que ponto a visibilidade de brinquedos durantea tarefa onde brincadeiras eram incluídas, seria um fator fundamental no desempenho na medida' em que favoreceria a memorização das premissas. Os Experimentos I, II e III demonstraram que, como no estudo de Dias e Harris (submetido), o desempenho das crianças era significativamente melhor quando as premissas eram apresentadas dentro de um contexto de brincadeira do que quando eram apresentadas de modo verbal comum. O contexto de faz-de-conta mais do que a visível presença dos brinquedos durante a apresentação é que facilita o raciocínio das crianças quando as premissas dos problemas vão de encontro à suas experiências

Regras morais e convencionais no raciocínio de crianças

A make-believe mode can help children to construct a selfcontainedworld within which they accept premises and conclusions thathave no counterpart in their everyday experience (Dias e Harris, 1988a,b, c; no prelo a e b). Thus, we asked if the construct of that make-believeworld would have the same effect in syllogistic problems that convene either moral or conventional rules. The results show that neither of thepopulations studied (Brazilian and English children from medium SESfamilies and Brazilian children from Orphanages) distinguish betweenmoral and conventional rules as found by Turiel (1983). The make-believemode helped the performance of children from medium SES familes.However, children from Orphanages Showed similar reasoning under thetwo types of context, as children did with known fact premises that agreedwith subject's experience (see Hawkins, Pea, Glick & Scribner, 1984;Dias e Harris, 1988a, b). For these children premises that contravenemoral or conventional rules to the two other populations, seems beaccepted as empirically true without need of the make-believe play.RESUMO - Uma apresentação de brincadeira de faz-de-conta pode ser usada para induzir crianças a criarem um mundo independente, onde os eventos podem ocorrer diferentemente daqueles do mundo empírico, facilitando assim a ocorrência de raciocínio dedutivo com base em premissas contrárias aos fatos (Dias e Harris, 1988a, b, c; no prelo a e b). Analisou-se então, se a criação deste mundo de faz-de-conta proporciona o mesmo efeito em problemas silogísticos que contêm premissas contrárias aos dorhfnios morais ou convencionais. Os resultados mostram que, em nenhuma das três amostras estudadas (crianças brasileiras e inglesas de NSE médio, e crianças brasileiras de orfanatos), houve distinção entre regras morais e convencionais como encontrado por Turiel (1983). O contexto de brincadeira favoreceu, como nos estudos anteriores, o desempenho das crianças inglesas e brasileiras de NSE médio. No entanto, as crianças brasileiras de orfanatos raciocinaram similarmente em ambos os contextos, como acontece quando o conteúdo dos problemas está de acordo com a experiência dos sujeitos (ver Hawkins, Pea, Giick & Scríbner, 1984; Dias e Harris, 1988a, c). Para estas crianças, afirmações que representam violações de regras morais, convencionais ou empíricas para as outras amostras, pareciam ser aceitas como verdades empíricas, facilitando seu desempenho mesmo em problemas apresentados verbalmente, sem necessidade do contexto de brincadeira

Understanding the genetic basis of potato development using a multi-trait QTL analysis

Understanding the genetic basis of plant development in potato requires a proper characterization of plant morphology over time. Parameters related to different aging stages can be used to describe the developmental processes. It is attractive to map these traits simultaneously in a QTL analysis; because the power to detect a QTL will often be improved and it will be easier to identify pleiotropic QTLs. We included complex, agronomic traits together with plant development parameters in a multi-trait QTL analysis. First, the results of our analysis led to coherent insight into the genetic architecture of complex traits in potato. Secondly, QTL for parameters related to plant development were identified. Thirdly, pleiotropic regions for various types of traits were identified. Emergence, number of main stems, number of tubers and yield were explained by 9, 5, 4 and 6 QTL, respectively. These traits were measured once during the growing season. The genetic control of flowering, senescence and plant height, which were measured at regular time intervals, was explained by 9, 10 and 12 QTL, respectively. Genetic relationships between aboveground and belowground traits in potato were observed in 14 pleiotropic QTL. Some of our results suggest the presence of QTL-by-Environment interactions. Therefore, additional studies comparing development under different photoperiods are required to investigate the plasticity of the crop

Search for lepton-flavor violation at HERA

A search for lepton-flavor-violating interactions $e p \to \mu X$ and $e p\to \tau X$ has been performed with the ZEUS detector using the entire HERA I data sample, corresponding to an integrated luminosity of 130 pb^{-1}. The data were taken at center-of-mass energies, $\sqrt{s}$, of 300 and 318 GeV. No evidence of lepton-flavor violation was found, and constraints were derived on leptoquarks (LQs) that could mediate such interactions. For LQ masses below $\sqrt{s}$, limits were set on $\lambda_{eq_1} \sqrt{\beta_{\ell q}}$, where $\lambda_{eq_1}$ is the coupling of the LQ to an electron and a first-generation quark $q_1$, and $\beta_{\ell q}$ is the branching ratio of the LQ to the final-state lepton $\ell$ ($\mu$ or $\tau$) and a quark $q$. For LQ masses much larger than $\sqrt{s}$, limits were set on the four-fermion interaction term $\lambda_{e q_\alpha} \lambda_{\ell q_\beta} / M_{\mathrm{LQ}}^2$ for LQs that couple to an electron and a quark $q_\alpha$ and to a lepton $\ell$ and a quark $q_\beta$, where $\alpha$ and $\beta$ are quark generation indices. Some of the limits are also applicable to lepton-flavor-violating processes mediated by squarks in $R$-Parity-violating supersymmetric models. In some cases, especially when a higher-generation quark is involved and for the process $e p\to \tau X$, the ZEUS limits are the most stringent to date.Comment: 37 pages, 10 figures, Accepted by EPJC. References and 1 figure (Fig. 6) adde

Multijet production in neutral current deep inelastic scattering at HERA and determination of alpha_s

Multijet production rates in neutral current deep inelastic scattering have been measured in the range of exchanged boson virtualities 10 < Q2 < 5000 GeV2. The data were taken at the ep collider HERA with centre-of-mass energy sqrt(s) = 318 GeV using the ZEUS detector and correspond to an integrated luminosity of 82.2 pb-1. Jets were identified in the Breit frame using the k_T cluster algorithm in the longitudinally invariant inclusive mode. Measurements of differential dijet and trijet cross sections are presented as functions of jet transverse energy E_{T,B}{jet}, pseudorapidity eta_{LAB}{jet} and Q2 with E_{T,B}{jet} > 5 GeV and -1 < eta_{LAB}{jet} < 2.5. Next-to-leading-order QCD calculations describe the data well. The value of the strong coupling constant alpha_s(M_Z), determined from the ratio of the trijet to dijet cross sections, is alpha_s(M_Z) = 0.1179 pm 0.0013(stat.) {+0.0028}_{-0.0046}(exp.) {+0.0064}_{-0.0046}(th.)Comment: 22 pages, 5 figure

Measurement of (anti)deuteron and (anti)proton production in DIS at HERA

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300--318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3<p_T/M<0.7. The particle rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements.Comment: 26 pages, 9 figures, 5 tables, submitted to Nucl. Phys.

Photoproduction of D∗±D^{*\pm} mesons associated with a leading neutron

The photoproduction of $D^{*\pm} (2010)$ mesons associated with a leading neutron has been observed with the ZEUS detector in $ep$ collisions at HERA using an integrated luminosity of 80 pb$^{-1}$. The neutron carries a large fraction, {$x_L>0.2$}, of the incoming proton beam energy and is detected at very small production angles, {$\theta_n<0.8$ mrad}, an indication of peripheral scattering. The $D^*$ meson is centrally produced with pseudorapidity {$|\eta| 1.9$ GeV}, which is large compared to the average transverse momentum of the neutron of 0.22 GeV. The ratio of neutron-tagged to inclusive $D^*$ production is $8.85\pm 0.93({\rm stat.})^{+0.48}_{-0.61}({\rm syst.})\%$ in the photon-proton center-of-mass energy range {$130 <W<280$ GeV}. The data suggest that the presence of a hard scale enhances the fraction of events with a leading neutron in the final state.Comment: 28 pages, 4 figures, 2 table

Measurement of beauty production in deep inelastic scattering at HERA

The beauty production cross section for deep inelastic scattering events with at least one hard jet in the Breit frame together with a muon has been measured, for photon virtualities Q^2 > 2 GeV^2, with the ZEUS detector at HERA using integrated luminosity of 72 pb^-1. The total visible cross section is sigma_b-bbar (ep -> e jet mu X) = 40.9 +- 5.7 (stat.) +6.0 -4.4 (syst.) pb. The next-to-leading order QCD prediction lies about 2.5 standard deviations below the data. The differential cross sections are in general consistent with the NLO QCD predictions; however at low values of Q^2, Bjorken x, and muon transverse momentum, and high values of jet transverse energy and muon pseudorapidity, the prediction is about two standard deviations below the data.Comment: 18 pages, 4 figure

Measurement of charm fragmentation ratios and fractions in photoproduction at HERA

The production of D^*+, D^0, D^+, D_s^+ and Lambda_c^+ charm hadrons and their antiparticles in ep scattering at HERA was measured with the ZEUS detector using an integrated luminosity of 79 pb^-1. The measurement has been performed in the photoproduction regime with the exchanged-photon virtuality Q^2 < 1 GeV^2 and for photon-proton centre-of-mass energies in the range 130 < W < 300 GeV. The charm hadrons were reconstructed in the range of transverse momentum p_T(D, Lambda_c) > 3.8 GeV and pseudorapidity |eta(D, Lambda_c)| < 1.6. The production cross sections were used to determine the ratio of neutral and charged D-meson production rates, R_u/d, the strangeness-suppression factor, gamma_s, and the fraction of charged D mesons produced in a vector state, P_v^d. The measured R_u/d and gamma_s values agree with those obtained in deep inelastic scattering and in e^+e^- annihilations. The measured P_v^d value is smaller than, but consistent with, the previous measurements. The fractions of c quarks hadronising as a particular charm hadron, f(c -> D, Lambda_c), were derived in the given kinematic range. The measured open-charm fragmentation fractions are consistent with previous results, although the measured f(c -> D^*+) is smaller and f(c -> Lambda_c^+) is larger than those obtained in e^+e^- annihilations. These results generally support the hypothesis that fragmentation proceeds independently of the hard sub-process.Comment: 29 pages, 5 figures, 6 tables; minor text revision

Observation of isolated high-E_T photons in deep inelastic scattering

First measurements of cross sections for isolated prompt photon production in deep inelastic ep scattering have been made using the ZEUS detector at the HERA electron-proton collider using an integrated luminosity of 121 pb^-1. A signal for isolated photons in the transverse energy and rapidity ranges 5 < E_T^gamma < 10 GeV and -0.7 < eta^gamma < 0.9 was observed for virtualities of the exchanged photon of Q^2 > 35 GeV^2. Cross sections are presented for inclusive prompt photons and for those accompanied by a single jet in the range E_T^jet \geq 6 GeV and -1.5 \leq eta^jet < 1.8. Calculations at order alpha^3alpha_s describe the data reasonably well.Comment: 16 pages, 5 figure