7,696 research outputs found

    Free Your Mind: Contemporary Racial Attitudes and Post Racial Theory

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    The inauguration of the United States first Black President has prompted mass discussions of race relations in America. It is often articulated that America is now in a post-racial society. However, the question still remains: does the election of a Black president demonstrate that America is now a color-blind society? To answer this question, we rely on data collected by PEW (2007). Our results suggest that white and African Americans differ significantly in the extent to which they express post-racial attitudes. Specifically, we find that whites more commonly express post-racial attitudes, claiming that racism and discrimination are rare, in opposition to African American views. On the other hand, blacks are more likely to believe that discrimination still occurs. We further find that whites\u27 post-racial beliefs are significant determinants of their attitudes towards race-related policies, such as affirmative action. Keywords: Race, Obama, Post-racial, Public Opinion, Racial Attitudes, Racial Politics, African American

    Zeno and anti-Zeno polarization control of spin-ensembles by induced dephasing

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    We experimentally and theoretically demonstrate the purity (polarization) control of qubits entangled with multiple spins, using induced dephasing in nuclear magnetic resonance (NMR) setups to simulate repeated quantum measurements. We show that one may steer the qubit ensemble towards a quasi-equilibrium state of certain purity, by choosing suitable time intervals between dephasing operations. These results demonstrate that repeated dephasing at intervals associated with the anti-Zeno regime lead to ensemble purification, whereas those associated with the Zeno regime lead to ensemble mixing.Comment: Main Text: 5 pages, 2 figures. Sup. Inf.: 5pages, 1 figur

    Distinct subpopulations of enteric neuronal progenitors defined by time of development, sympathoadrenal lineage markers and Mash-1-dependence

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    Enteric and sympathetic neurons have previously been proposed to be lineally related. We present independent lines of evidence that suggest that enteric neurons arise from at least two lineages, only one of which expresses markers in common with sympathoadrenal cells. In the rat, sympathoadrenal markers are expressed, in the same order as in sympathetic neurons, by a subset of enteric neuronal precursors, which also transiently express tyrosine hydroxylase. If this precursor pool is eliminated in vitro by complement-mediated lysis, enteric neurons continue to develop; however, none of these are serotonergic. In the mouse, the Mash-1−/− mutation, which eliminates sympathetic neurons, also prevents the development of enteric serotonergic neurons. Other enteric neuronal populations, however, including those that contain calcitonin gene related peptide are present. Enteric tyrosine hydroxylase-containing cells co-express Mash-1 and are eliminated by the Mash-1−/− mutation, consistent with the idea that in the mouse, as in the rat, these precursors generate serotonergic neurons. Serotonergic neurons are generated early in development, while calcitonin gene related peptide-containing enteric neurons are generated much later. These data suggest that enteric neurons are derived from at least two progenitor lineages. One transiently expresses sympathoadrenal markers, is Mash-1-dependent, and generates early-born enteric neurons, some of which are serotonergic. The other is Mash-1-independent, does not express sympathoadrenal markers, and generates late-born enteric neurons, some of which contain calcitonin gene related peptide

    Scalable solid-state quantum processor using subradiant two-atom states

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    We propose a realization of a scalable, high-performance quantum processor whose qubits are represented by the ground and subradiant states of effective dimers formed by pairs of two-level systems coupled by resonant dipole-dipole interaction. The dimers are implanted in low-temperature solid host material at controllable nanoscale separations. The two-qubit entanglement either relies on the coherent excitation exchange between the dimers or is mediated by external laser fields.Comment: 4 pages, 3 figure

    Control of multiatom entanglement in a cavity

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    We propose a general formalism for analytical description of multiatomic ensembles interacting with a single mode quantized cavity field under the assumption that most atoms remain un-excited on average. By combining the obtained formalism with the nilpotent technique for the description of multipartite entanglement we are able to overview in a unified fashion different probabilistic control scenarios of entanglement among atoms or examine atomic ensembles. We then apply the proposed control schemes to the creation of multiatom states useful for quantum information.Comment: 11 pages, 1 figure. Finalized versio

    Measurement of Counting Statistics of Electron Transport in a Tunnel Junction

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    We present measurements of the time-dependent fluctuations in electrical current in a voltage-biased tunnel junction. We were able to simultaneously extract the first three moments of the tunnel current counting statistics. Detailed comparison of the second and the third moment reveals that counting statistics is accurately described by the Poissonian distribution expected for spontaneous current fluctuations due to electron charge discreteness, realized in tunneling transport at negligible coupling to environment.Comment: bibliography expande

    First observation of Bs0 → D*s2+XÎŒ-Îœ decays

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    Using data collected with the LHCb detector in proton–proton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays B0s→D+sXΌ−Μ and B0s→D0K+XΌ−Μ are detected. Two structures are observed in the D0K+ mass spectrum at masses consistent with the known Ds1(2536)+ and D∗s22573)+ mesons. The measured branching fractions relative to the total B0s semileptonic rate are B(B0s→D∗+s2XΌ−Μ)/B(B0s→XΌ−Μ) = (3.3±1.0±0.4)%, and B(B0s→D+s1XΌ−Μ)/B(B0s→XΌ−Μ) = (5.4±1.2±0.5)%, where the ïŹrst uncertainty is statistical and the second is systematic. This is the ïŹrst observation of the D∗+s2 state in B0s decays; we also measure its mass and width

    Evidence That the RNA Methylation and Poly(A) Polymerase Stimulatory Activities of Vaccinia Virus Protein VP39 Do Not Impinge upon One Another

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    AbstractVaccinia protein VP39 has two RNA modifying activities. In monomeric form, it acts as an mRNA cap-specific 2â€Č-O-methyltransferase, specifically modifying the ribose moiety of the first transcribed nucleotide of m7G-capped mRNA. In association with VP55, the catalytic subunit of the vaccinia poly(A) polymerase, VP39 facilitates the rapid elongation of poly(A) tails that are already greater than ∌35 nt in length. Introducing new assays, we provide evidence that substrates for each of VP39's two activities do not detectably modulate the converse reaction and that VP39's 2â€Č-O-methyltransferase activity is not significantly affected by its association with VP55. In an electrophoretic mobility shift assay, VP39 interacted with a short (5 nucleotide) RNA only when the latter was m7G-capped. Complexes with longer (22 nucleotide) RNAs were more stable (i.e., cap-independent) but were further stabilized by the presence of an m7G cap. An additional complex was observed at elevated RNA:protein molar ratios, indicating the presence of two RNA binding sites per VP39 molecule. Interaction at one of these sites was stabilized by the cap structure. Additional experiments indicated that RNA molecules undergoing poly(A) tail elongation by the VP55-VP39 heterodimer are not favored as cap-methylation substrates
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