5,256 research outputs found
Mt. Everest—we are going to lose many: a survey of fingerprint examiners’ attitudes towards probabilistic reporting
Over the past decade, with increasing scientific scrutiny on forensic reporting practices, there have been several efforts to introduce statistical thinking and probabilistic reasoning into forensic practice. These efforts have been met with mixed reactions—a common one being scepticism, or downright hostility, towards this objective. For probabilistic reasoning to be adopted in forensic practice, more than statistical knowledge will be necessary. Social scientific knowledge will be critical to effectively understand the sources of concern and barriers to implementation. This study reports the findings of a survey of forensic fingerprint examiners about reporting practices across the discipline and practitioners’ attitudes and characterizations of probabilistic reporting. Overall, despite its adoption by a small number of practitioners, community-wide adoption of probabilistic reporting in the friction ridge discipline faces challenges. We found that almost no respondents currently report probabilistically. Perhaps more surprisingly, most respondents who claimed to report probabilistically, in fact, do not. Furthermore, we found that two-thirds of respondents perceive probabilistic reporting as ‘inappropriate’—their most common concern being that defence attorneys would take advantage of uncertainty or that probabilistic reports would mislead, or be misunderstood by, other criminal justice system actors. If probabilistic reporting is to be adopted, much work is still needed to better educate practitioners on the importance and utility of probabilistic reasoning in order to facilitate a path towards improved reporting practices
Cosmological neutrino bounds for non-cosmologists
I briefly review cosmological bounds on neutrino masses and the underlying
gravitational physics at a level appropriate for readers outside the field of
cosmology. For the case of three massive neutrinos with standard model
freezeout, the current 95% upper limit on the sum of their masses is 0.42 eV. I
summarize the basic physical mechanism making matter clustering such a
sensitive probe of massive neutrinos. I discuss the prospects of doing still
better in coming years using tools such as lensing tomography, approaching a
sensitivity around 0.03 eV. Since the lower bound from atmospheric neutrino
oscillations is around 0.05 eV, upcoming cosmological measurements should
detect neutrino mass if the technical and fiscal challenges can be met.Comment: 4 pages, 2 figs, in "Neutrino Physics", Proceedings of Nobel
Symposium 129, eds., L Bergstrom, O. Botner, P. Carlson, P. O. Hulth, and T.
Ohlsso
Using GIS to integrate old and new archaeological data from Stone Age deposits in Karonga, Malawi
The Karonga District of northern Malawi has an extensive Stone Age archaeological record, primarily represented by stone artefacts that occur in both superficial and buried contexts. Work conducted in the 1960s provided initial documentation of this record. Some of this was presented in summary form in a small number of publications. However, most data were restricted to unpublished field notes, maps, and other static or largely inaccessible formats. GIS has been an essential tool for bringing together these diverse datasets in a digital format to facilitate integration of new research and promote reinvestigation of old sites. Examples from both the regional and site scale demonstrate how old data have been combined with recent survey and excavation data to document, analyse, interpret, and archive current knowledge about the rich Stone Age record of northern Malawi. A significant result from this approach has been the suggested reinterpretation of the Mwanganda’s Village Site
The star cluster - field star connection in nearby spiral galaxies I. Data analysis techniques and application to NGC 4395
It is generally assumed that a large fraction of stars are initially born in
clusters. However, a large fraction of these disrupt on short timescales and
the stars end up belonging to the field. Understanding this process is of
paramount importance if we wish to constrain the star formation histories of
external galaxies using star clusters. We attempt to understand the relation
between field stars and star clusters by simultaneously studying both in a
number of nearby galaxies. As a pilot study, we present results for the
late-type spiral NGC 4395 using HST/ACS and HST/WFPC2 images. Different
detection criteria were used to distinguish point sources (star candidates) and
extended objects (star cluster candidates). Using a synthetic CMD method, we
estimated the star formation history. Using simple stellar population model
fitting, we calculated the mass and age of the cluster candidates. The field
star formation rate appears to have been roughly constant, or to have possibly
increased by up to about a factor of two, for ages younger than 300 Myr
within the fields covered by our data. Our data do not allow us to constrain
the star formation histories at older ages. We identify a small number of
clusters in both fields. Neither massive ( M) clusters nor
clusters with ages Gyr were found in the galaxy and we found few
clusters older than 100 Myr. Based on our direct comparison of field stars and
clusters in NGC 4395, we estimate the ratio of star formation rate in clusters
that survive for to years to the total star formation to be
. We suggest that this relatively low value is caused
by the low star formation rate of NGC 4395.Comment: 16 pages, 20 figures, accepted for publication in A&
Why is the Fraction of Four-Image Radio Lens Systems So High?
We investigate the frequency of two- and four-image gravitational lens
systems in the Jodrell-VLA Astrometric Survey (JVAS) and Cosmic Lens All-Sky
Survey (CLASS), and the possible implications for dark matter halo properties.
A simple lensing statistics model, which describes lens galaxies as singular
isothermal ellipsoids with a projected axis ratio distribution derived from the
surface brightness ellipticities of early-type galaxies in the Coma cluster, is
ruled out at the 98% level since it predicts too few four-image lenses (quads).
We consider a range of factors that may be increasing the frequency of radio
quads, including external shear fields, mass distributions flatter than the
light, shallow lensing mass profiles, finite core radii, satellite galaxies,
and alterations to the luminosity function for faint flat-spectrum radio
sources. We find that none of these mechanisms provide a compelling solution to
the quad problem on their own while remaining consistent with other
observational constraints.Comment: Final version. 27 pages, including 9 figs, minor typos corrected, ApJ
in press (June 2001
Toward the observation of interference effects in nonlinear Compton scattering
The photon spectrum from electrons scattering on multiple laser pulses
exhibits interference effects not present for scattering on a single pulse. We
investigate the conditions required for the experimental observation of these
interference effects in electron-laser collisions, in particular analysing the
roles of the detector resolution and the transverse divergence of the pump
electron beam.Comment: 8 pages, 5 figure
Intrinsic galaxy shapes and alignments I: Measuring and modelling COSMOS intrinsic galaxy ellipticities
The statistical properties of the ellipticities of galaxy images depend on
how galaxies form and evolve, and therefore constrain models of galaxy
morphology, which are key to the removal of the intrinsic alignment
contamination of cosmological weak lensing surveys, as well as to the
calibration of weak lensing shape measurements. We construct such models based
on the halo properties of the Millennium Simulation and confront them with a
sample of 90,000 galaxies from the COSMOS Survey, covering three decades in
luminosity and redshifts out to z=2. The ellipticity measurements are corrected
for effects of point spread function smearing, spurious image distortions, and
measurement noise. Dividing galaxies into early, late, and irregular types, we
find that early-type galaxies have up to a factor of two lower intrinsic
ellipticity dispersion than late-type galaxies. None of the samples shows
evidence for redshift evolution, while the ellipticity dispersion for late-type
galaxies scales strongly with absolute magnitude at the bright end. The
simulation-based models reproduce the main characteristics of the intrinsic
ellipticity distributions although which model fares best depends on the
selection criteria of the galaxy sample. We observe fewer close-to-circular
late-type galaxy images in COSMOS than expected for a sample of randomly
oriented circular thick disks and discuss possible explanations for this
deficit.Comment: 18 pages, 8 figures; updated simulations and galaxy sample
definition, more galaxy samples analysed; matches version published in MNRA
'Sexercise': Working out heterosexuality in Jane Fonda’s fitness books
This is an Author's Accepted Manuscript of an article published in Leisure Studies, 30(2), 237 - 255, 2011, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/02614367.2010.523837.This paper explores the connection between the promotion of heterosexual norms in women’s fitness books written by or in the name of Jane Fonda during the 1980s and the commodification of women’s fitness space in both the public and private spheres. The paper is set in the absence of overt discussions of normative heterosexuality in leisure studies and draws on critical heterosexual scholarship as well as the growing body of work theorising geographies of corporeality and heterosexuality. Using the principles of media discourse analysis, the paper identifies three overlapping characteristics of heterosexuality represented in Jane Fonda’s fitness books, and embodied through the exercise regimes: respectable heterosexual desire, monogamous procreation and domesticity. The paper concludes that the promotion and prescription of exercise for women in the Jane Fonda workout books centred on the reproduction and embodiment of heterosexual corporeality. Set within an emerging commercial landscape of women’s fitness in the 1980s, such exercise practices were significant in the legitimation and institutionalisation of heteronormativity
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