5,001 research outputs found

    Theoretical value of the recommended expanded European Standard Set of STR loci for the identification of human remains

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    We have undertaken a series of simulations to assess the effectiveness of commercially available sets of STR loci, including the loci recommended for inclusion in the expanded European Standard Set, for the purpose of human identification. A total of 9200 genotype simulations were performed using DNA · VIEW. The software was used to calculate likelihood ratios (LRs) for 23 groups of relatives, and to determine the probability of identification given scenarios that ranged between 10 and 250,000 victims. The additional loci included in the recommended expanded European Standard Set, when used in conjunction with the Identifiler® kit, significantly improved the typical LRs for tested scenarios and the likely success of providing correct identifications

    Structural, magnetic, and transport properties of Co2_2FeSi Heusler films

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    We report the deposition of thin Co2_2FeSi films by RF magnetron sputtering. Epitaxial (100)-oriented and L21_1 ordered growth is observed for films grown on MgO(100) substrates. (110)-oriented films on Al2_2O3_3(110) show several epitaxial domains in the film plane. Investigation of the magnetic properties reveals a saturation magnetization of 5.0 muB/f.u.mu_B/f.u. at low temperatures. The temperature dependence of the resistivity rhoxx(T)rho_{xx}(T) exhibits a crossover from a T^3.5 law at T<50K to a T^1.65 behaviour at elevated temperatures. rhoxx(H)rho_{xx}(H) shows a small anisotropic magnetoresistive effect. A weak dependence of the normal Hall effect on the external magnetic field indicates the compensation of electron and hole like contributions at the Fermi surface.Comment: 10 pages, 9 figures to be published in J. Phys. D: Appl. Phy

    Comment on "Fano Resonance for Anderson Impurity Systems"

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    In a recent Letter, Luo et al. (Phys. Rev. Lett. 92, 256602 (2004)) analyze the Fano line shapes obtained from scanning tunneling spectroscopy (STS) of transition metal impurities on a simple metal surface, in particular of the Ti/Au(111) and Ti/Ag(100) systems. As the key point of their analysis, they claim that there is not only a Fano interference effect between the impurity d-orbital and the conduction electron continuum, as derived in Ujsaghy et al. (Phys. Rev. Lett. 85, 2557 (2000)), but that the Kondo resonance in the d-electron spectral density has by itself a second Fano line shape, leading to the experimentally observed spectra. In the present note we point out that this analysis is conceptually incorrect. Therefore, the quantitative agreement of the fitted theoretical spectra with the experimental results is meaningless.Comment: 1 page, no figures. Accepted for publication in PRL; revised version uploaded on November 18th, 200

    Electron beam driven alkali metal atom source for loading a magneto-optical trap in a cryogenic environment

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    We present a versatile and compact electron beam driven source for alkali metal atoms, which can be implemented in cryostats. With a heat load of less than 10mW, the heat dissipation normalized to the atoms loaded into the magneto-optical Trap (MOT), is about a factor 1000 smaller than for a typical alkali metal dispenser. The measured linear scaling of the MOT loading rate with electron current observed in the experiments, indicates that electron stimulated desorption is the corresponding mechanism to release the atoms.Comment: 5 pages, 3 figure

    Fehlerbaumanalyse von periodisch inspizierbaren Systemen mit Hilfe von Monte Carlo Methoden

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    The Extended Baryon Oscillation Spectroscopic Survey: Variability Selection and Quasar Luminosity Function

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    The SDSS-IV/eBOSS has an extensive quasar program that combines several selection methods. Among these, the photometric variability technique provides highly uniform samples, unaffected by the redshift bias of traditional optical-color selections, when z=2.73.5z= 2.7 - 3.5 quasars cross the stellar locus or when host galaxy light affects quasar colors at z<0.9z < 0.9. Here, we present the variability selection of quasars in eBOSS, focusing on a specific program that led to a sample of 13,876 quasars to gdered=22.5g_{\rm dered}=22.5 over a 94.5 deg2^2 region in Stripe 82, an areal density 1.5 times higher than over the rest of the eBOSS footprint. We use these variability-selected data to provide a new measurement of the quasar luminosity function (QLF) in the redshift range 0.68<z<4.00.68<z<4.0. Our sample is denser, reaches deeper than those used in previous studies of the QLF, and is among the largest ones. At the faint end, our QLF extends to Mg(z ⁣= ⁣2)=21.80M_g(z\!=\!2)=-21.80 at low redshift and to Mg(z ⁣= ⁣2)=26.20M_g(z\!=\!2)=-26.20 at z4z\sim 4. We fit the QLF using two independent double-power-law models with ten free parameters each. The first model is a pure luminosity-function evolution (PLE) with bright-end and faint-end slopes allowed to be different on either side of z=2.2z=2.2. The other is a simple PLE at z<2.2z<2.2, combined with a model that comprises both luminosity and density evolution (LEDE) at z>2.2z>2.2. Both models are constrained to be continuous at z=2.2z=2.2. They present a flattening of the bright-end slope at large redshift. The LEDE model indicates a reduction of the break density with increasing redshift, but the evolution of the break magnitude depends on the parameterization. The models are in excellent accord, predicting quasar counts that agree within 0.3\% (resp., 1.1\%) to g<22.5g<22.5 (resp., g<23g<23). The models are also in good agreement over the entire redshift range with models from previous studies.Comment: 15 pages, 12 figures, accepted for publication in A&

    Iterated Binomial Sums and their Associated Iterated Integrals

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    We consider finite iterated generalized harmonic sums weighted by the binomial (2kk)\binom{2k}{k} in numerators and denominators. A large class of these functions emerges in the calculation of massive Feynman diagrams with local operator insertions starting at 3-loop order in the coupling constant and extends the classes of the nested harmonic, generalized harmonic and cyclotomic sums. The binomially weighted sums are associated by the Mellin transform to iterated integrals over square-root valued alphabets. The values of the sums for NN \rightarrow \infty and the iterated integrals at x=1x=1 lead to new constants, extending the set of special numbers given by the multiple zeta values, the cyclotomic zeta values and special constants which emerge in the limit NN \rightarrow \infty of generalized harmonic sums. We develop algorithms to obtain the Mellin representations of these sums in a systematic way. They are of importance for the derivation of the asymptotic expansion of these sums and their analytic continuation to NCN \in \mathbb{C}. The associated convolution relations are derived for real parameters and can therefore be used in a wider context, as e.g. for multi-scale processes. We also derive algorithms to transform iterated integrals over root-valued alphabets into binomial sums. Using generating functions we study a few aspects of infinite (inverse) binomial sums.Comment: 62 pages Latex, 1 style fil

    Incoherent Eta Photoproduction from the Deuteron near Threshold

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    Very recent data for the reaction gamma+d ->eta np, namely total cross sections, angular and momentum spectra, are analyzed within a model that includes contributions from the impulse approximation and next order corrections due to the np and eta-N interactions in the final state. Comparison between the calculations and the new data indicate sizable contributions from the np and eta-N final state interactions. Some systematic discrepancies between the calculations and the data are also found
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