7,246 research outputs found
Geographic profiling in Nazi Berlin: fact and fiction
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
non compliant version, depositor contacte
Polchinski equation, reparameterization invariance and the derivative expansion
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
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
=--, for SU() QCD with quark flavours.
This can be accomplished using exact large- 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- 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
-ratio, the analogous -lepton decay ratio , and
Deep Inelastic Scattering (DIS) sum rules, by comparing it with the exact NNLO
results in the effective charge RS. For the -ratio and , 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 -ratio could determine
to three-significant figures, and for the we
estimate a theoretical uncertainty
corresponding to . 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
© 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
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
We exploit the fact that within massless perturbative QCD the same Green's
function determines the hadronic contribution to the decay width and the
moments of the 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 decay width
allows one then to predict the first few moments of the spectral density in
annihilations integrated up to 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
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 QCD corrections to the Euclidean
quantities: the -annihilation -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 -function
are further applied to estimate the QCD corrections to the
Minkowskian quantities and . The problem of the fixation of the uncertainties due to the
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
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 . We
stress the importance of an accurate measurement of the GLS sum rule and in
particular of its dependence.Comment: Latex 19 pages and 4 Postscript figures appended at the end of this
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