31,273,683 research outputs found

    A Formative Assessment of Geologic Time for High School Earth Science Students

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    Provides pedagogical insight concerning the assessment strategy using formative assessment The resource being annotated is: http://www.dlese.org/dds/catalog_DLESE-000-000-004-784.htm

    New Physics in b --> s bar(s) s Decay

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    We perform a model-independent analysis of the data on branching ratios and CP asymmetries of B→ϕKB\to\phi K and B→η(′)K(∗)B\to\eta^{(')} K^{(*)} modes. The present data is encouraging to look for indirect evidences of physics beyond the Standard Model. We investigate the parameter spaces for different possible Lorentz structures of the new physics four-Fermi interaction. It is shown that if one takes the data at 1σ1\sigma confidence level, only one particular Lorentz structure is allowed. Possible consequences for the BsB_s system are also discussed.Comment: 9 pages, 3 encapsulated figures, minor changes in the text, conclusions unchanged, a few references added, version to appear in PL

    Color suppressed contributions to the decay modes B_{d,s} -> D_{s,d} D_{s,d}, B_{d,s} -> D_{s,d} D^*_{s,d}, and B_{d,s} -> D^*_{s,d} D^*_{s,d}

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    The amplitudes for decays of the type Bd,s→Ds,dDs,dB_{d,s} \to D_{s,d} D_{s,d}, have no factorizable contributions, while Bd,s→Ds,dDs,d∗B_{d,s} \to D_{s,d} D^*_{s,d}, and Bd,s→Ds,d∗Ds,d∗B_{d,s} \to D^*_{s,d} D^*_{s,d} have relatively small factorizable contributions through the annihilation mechanism. The dominant contributions to the decay amplitudes arise from chiral loop contributions and tree level amplitudes which can be obtained in terms of soft gluon emissions forming a gluon condensate. We predict that the branching ratios for the processes Bˉd0→Ds+Ds−\bar B^0_d \to D_s^+ D_s^-, Bˉd0→Ds+∗Ds−\bar B^0_d \to D_s^{+*} D_s^- and Bˉd0→Ds+Ds−∗\bar B^0_d \to D_s^+ D_s^{-*} are all of order (2−3)×10−4(2- 3) \times 10^{-4}, while Bˉs0→Dd+Dd−\bar B^0_s \to D_d^+ D_d^-, Bˉs0→Dd+∗Dd−\bar B^0_s \to D_d^{+*} D_d^- and Bˉs0→Dd+Dd−∗\bar B^0_s \to D_d^+ D_d^{-*} are of order (4−7)×10−3(4- 7) \times 10^{-3}. We obtain branching ratios for two D∗D^*'s in the final state of order two times bigger.Comment: 15 pages, 4 figure

    Dynamic (S,s) Economies

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    In this paper we provide a framework to study the aggregate dynamic behavior of an economy where individual units follow (S,s) policies. We characterize structural and stochastic heterogeneities that ensure convergence of the economy's aggregate to that of its frictionless counterpart, determine the speed at which convergence takes place, and describe the transitional dynamics of this economy. In particular, we consider a dynamic economy where agents differ in their initial positions within their bands and face both stochastic and structural heterogeneity; where the former refers to the presence of (unit specific) idiosyncratic shocks, and the latter to differences in the widths of units' (S,s) bands and their response to aggregate shocks. We study the evolution of the economy's aggregate and the evolution of the difference between this aggregate and that of an economy without macroeconomic friction, where the latter pertains to a situation where individual units adjust with no delay to all shocks. We also examine the sensitivity of this difference to common shocks. For example, in the retail inventory problem the aggregate deviation and sensitivity to common shocks correspond to the aggregate inventory level and its sensitivity to aggregate demand shocks, respectively.

    Coulomb effects in a ballistic one-channel S-S-S device

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    We develop a theory of Coulomb oscillations in superconducting devices in the limit of small charging energy EC≪ΔE_C \ll \Delta. We consider a small superconducting grain of finite capacity connected to two superconducting leads by nearly ballistic single-channel quantum point contacts. The temperature is supposed to be very low, so there are no single-particle excitations on the grain. Then the behavior of the system may be described as quantum mechanics of the superconducting phase on the island. The Josephson energy as a function of this phase has two minima which become degenerate at the phase difference on the leads equal to π\pi, the tunneling amplitude between them being controlled by the gate voltage at the grain. We find the Josephson current and its low-frequency fluctuations and predict their periodic dependence on the induced charge Qx=CVgQ_x=C V_g with period 2e2e.Comment: 11 pages, REVTeX, 10 figures, uses eps

    2-aminophenols containing electron-withdrawing groups from N-aryl hydroxylamines

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    Reaction of substituted N-aryl hydroxylamines with methanesulfonyl chloride, p-toluenesulfonyl chloride, or trifluoromethanesulfonic anhydride under basic conditions leads to the rearranged 2-aminophenols (45-94%). The overall reaction sequence can be performed using polymer-supported sulfonyl chloride resin allowing for the effective conversion of N-aryl hydroxylamines to the 2-aminophenols without the need for chromatography
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