7,246 research outputs found

    Geographic profiling in Nazi Berlin: fact and fiction

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    Geographic profiling uses the locations of connected crime sites to make inferences about the probable location of the offender’s ‘anchor point’ (usually a home, but sometimes a workplace). We show how the basic ideas of the method were used in a Gestapo investigation that formed the basis of a classic German novel about domestic resistance to the Nazis during the Second World War. We use modern techniques to re-analyse this case, and show that these successfully locate the Berlin home address of Otto and Elise Hampel, who had distributed hundreds of anti-Nazi postcards, after analysing just 34 of the 214 incidents that took place before their arrest. Our study provides the first empirical evidence to support the suggestion that analysis of minor terrorism-related acts such as graffiti and theft could be used to help locate terrorist bases before more serious incidents occur

    Spatial targeting of infectious disease control: identifying multiple, unknown sources

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    Polchinski equation, reparameterization invariance and the derivative expansion

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    The connection between the anomalous dimension and some invariance properties of the fixed point actions within exact RG is explored. As an application, Polchinski equation at next-to-leading order in the derivative expansion is studied. For the Wilson fixed point of the one-component scalar theory in three dimensions we obtain the critical exponents \eta=0.042, \nu=0.622 and \omega=0.754.Comment: 28 pages, LaTeX with psfig, 12 encapsulated PostScript figures. A number wrongly quoted in the abstract correcte

    RS-invariant all-orders renormalon resummations for some QCD observables

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    We propose a renormalon-inspired resummation of QCD perturbation theory based on approximating the renormalization scheme (RS) invariant effective charge beta-function coefficients by the portion containing the highest power of bb=16(11N\frac{1}{6}(11N--2Nf)2N_{f}), for SU(NN) QCD with NfN_{f} quark flavours. This can be accomplished using exact large-NfN_{f} all-orders results. The resulting resummation is RS-invariant and the exact next-to-leading order (NLO) and next-to-NLO (NNLO) coefficients in any RS are included. This improves on a previously employed naive resummation of the leading-bb piece of the perturbative coefficients which is RS-dependent, making its comparison with fixed-order perturbative results ambiguous. The RS-invariant resummation is used to assess the reliability of fixed-order perturbation theory for the e+ee^{+}e^{-} RR-ratio, the analogous τ\tau-lepton decay ratio RτR_{\tau}, and Deep Inelastic Scattering (DIS) sum rules, by comparing it with the exact NNLO results in the effective charge RS. For the RR-ratio and RτR_{\tau}, where large-order perturbative behaviour is dominated by a leading ultra-violet renormalon singularity, the comparison indicates fixed-order perturbation theory to be very reliable. For DIS sum rules, which have a leading infra-red renormalon singularity, the performance is rather poor. In this way we estimate that at LEP/SLD energies ideal data on the RR-ratio could determine αs(MZ)\alpha_{s}(M_{Z}) to three-significant figures, and for the RτR_{\tau} we estimate a theoretical uncertainty δαs(mτ)0.008\delta\alpha_{s}(m_{\tau})\simeq0.008 corresponding to δαs(MZ)0.001\delta\alpha_{s}(M_{Z})\simeq0.001. This encouragingly small uncertainty is much less than has recently been deduced from comparison with the ambiguous naive resummation.Comment: 25 pages, uses LaTeX, 12 Postscript figures, epsfig.sty 'elsart.sty' and 'elsart12.sty' are available via anonymous-ftp at ftp://ftp.tex.ac.uk/tex-archive/macros/latex/contrib/supported/elsevie

    Using geographic profiling to locate elusive nocturnal animals: A case study with spectral tarsiers

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    © 2015 The Zoological Society of London. Estimates of biodiversity, population size, population density and habitat use have important implications for management of both species and habitats, yet are based on census data that can be extremely difficult to collect. Traditional assessment techniques are often limited by time and money and by the difficulties of working in certain habitats, and species become more difficult to find as population size decreases. Particular difficulties arise when studying elusive species with cryptic behaviours. Here, we show how geographic profiling (GP) - a statistical tool originally developed in criminology to prioritize large lists of suspects in cases of serial crime - can be used to address these problems. We ask whether GP can be used to locate sleeping sites of spectral tarsiers Tarsius tarsier in Sulawesi, Southeast Asia, using as input the positions at which tarsier vocalizations were recorded in the field. This novel application of GP is potentially of value as tarsiers are cryptic and nocturnal and can easily be overlooked in habitat assessments (e.g. in dense rainforest). Our results show that GP provides a useful tool for locating sleeping sites of this species, and indeed analysis of a preliminary dataset during field work strongly suggested the presence of a sleeping tree at a previously unknown location; two sleeping trees were subsequently found within 5m of the predicted site. We believe that GP can be successfully applied to locating the nests, dens or roosts of elusive animals such as tarsiers, potentially improving estimates of population size with important implications for management of both species and habitats.We thank Operation Wallacea for supporting S.C.F. in thisproject and for providing logistical support for the fieldwork,and Aidan Kelsey for invaluable assistance in the field. Wethank the Indonesian Institute of Sciences (LIPI) andKementerian Riset dan Teknologi Republik Indonesia(RISTEK) for providing permission to undertake the work(RISTEK permit no. 211/SIP/FRP/SM/VI/2013, and BalaiKonservasi Sumber Daya Alam (BKSDA) for theirassistance

    On the Chiral Phase Transition in the Linear Sigma Model

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    The Cornwall-Jackiw-Tomboulis (CJT) effective action for composite operators at finite temperature is used to investigate the chiral phase transition within the framework of the linear sigma model as the low-energy effective model of quantum chromodynamics (QCD). A new renormalization prescription for the CJT effective action in the Hartree-Fock (HF) approximation is proposed. A numerical study, which incorporates both thermal and quantum effect, shows that in this approximation the phase transition is of first order. However, taking into account the higher-loop diagrams contribution the order of phase transition is unchanged.Comment: 12 pages, 4 figure

    New high order relations between physical observables in perturbative QCD

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    We exploit the fact that within massless perturbative QCD the same Green's function determines the hadronic contribution to the τ\tau decay width and the moments of the e+ee^+e^- cross section. This allows one to obtain relations between physical observables in the two processes up to an unprecedented high order of perturbative QCD. A precision measurement of the τ\tau decay width allows one then to predict the first few moments of the spectral density in e+ee^+e^- annihilations integrated up to smτ2s\sim m_\tau^2 with high accuracy. The proposed tests are in reach of present experimental capabilities.Comment: 7 pages, Latex, no figure

    Estimates of the higher-order QCD corrections: Theory and Applications

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    We consider the further development of the formalism of the estimates of higher-order perturbative corrections in the Euclidean region, which is based on the application of the scheme-invariant methods, namely the principle of minimal sensitivity and the effective charges approach. We present the estimates of the order O(αs4)O(\alpha^{4}_{s}) QCD corrections to the Euclidean quantities: the e+ee^+e^--annihilation DD-function and the deep inelastic scattering sum rules, namely the non-polarized and polarized Bjorken sum rules and to the Gross--Llewellyn Smith sum rule. The results for the DD-function are further applied to estimate the O(αs4)O(\alpha_s^4) QCD corrections to the Minkowskian quantities R(s)=σtot(e+ehadrons)/σ(e+eμ+μ)R(s) = \sigma_{tot} (e^{+}e^{-} \to {\rm hadrons}) / \sigma (e^{+}e^{-} \to \mu^{+} \mu^{-}) and Rτ=Γ(τντ+hadrons)/Γ(τντνee)R_{\tau} = \Gamma (\tau \to \nu_{\tau} + {\rm hadrons}) / \Gamma (\tau \to \nu_{\tau} \overline{\nu}_{e} e). The problem of the fixation of the uncertainties due to the O(αs5)O(\alpha_s^5) corrections to the considered quantities is also discussed.Comment: revised version and improved version of CERN.TH-7400/94, LATEX 10 pages, six-loop estimates for R(s) in Table 2 are revised, thanks to J. Ellis for pointing numerical shortcomings (general formulae are non-affected). Details of derivations of six-loop estimates for R_tau are presente

    Next-to-next-to-leading order QCD analysis of the Gross-Llewellyn Smith sum rule and the higher twist effects

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    We present the next-to-next-to-leading order QCD analysis of the Gross-Llewellyn Smith (GLS) sum rule in deep inelastic lepton-nucleon scattering, taking into account dimension-two, twist-four power correction. We discuss in detail the renormalization scheme dependence of the perturbative QCD approximations, propose a procedure for an approximate treatment of the quark mass threshold effects and compare the results of our analysis to the recent experimental data of the CCFR collaboration. From this comparison we extract the value of the strong coupling constant αsnnl(MZ,MS)=0.115±0.001(stat)±0.005(syst)±0.003(twist)±0.0005(scheme)\alpha_{s}^{nnl}(M_{Z},\overline{\rm MS})= 0.115\pm0.001(stat)\pm0.005(syst)\pm0.003(twist)\pm0.0005(scheme). We stress the importance of an accurate measurement of the GLS sum rule and in particular of its Q2Q^{2} dependence.Comment: Latex 19 pages and 4 Postscript figures appended at the end of this fil
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