931 research outputs found
Gender-From-Iris or Gender-From-Mascara?
Predicting a person's gender based on the iris texture has been explored by
several researchers. This paper considers several dimensions of experimental
work on this problem, including person-disjoint train and test, and the effect
of cosmetics on eyelash occlusion and imperfect segmentation. We also consider
the use of multi-layer perceptron and convolutional neural networks as
classifiers, comparing the use of data-driven and hand-crafted features. Our
results suggest that the gender-from-iris problem is more difficult than has so
far been appreciated. Estimating accuracy using a mean of N person-disjoint
train and test partitions, and considering the effect of makeup - a combination
of experimental conditions not present in any previous work - we find a much
weaker ability to predict gender-from-iris texture than has been suggested in
previous work
Archival ethics: The truth of the matter
This essay explores the question of whether records professionals are as aware of the ethical dimensions of their work as they should be. It consider first the historical and professional context of archival ethics, then examines a recent case about business archives involving the author that suggests the need for renewed attention to professional ethics, and concludes with a discussion about how archivists might reconsider the ethical dimensions of their work
A comprehensive study of Cepheid variables in the Andromeda galaxy. Period distribution, blending and distance determination
Extragalactic Cepheids are the basic rungs of the cosmic distance scale. They
are excellent standard candles, although their luminosities and corresponding
distance estimates can be affected by the particular properties of the host
galaxy. Therefore, the accurate analysis of the Cepheid population in other
galaxies, and notably in the Andromeda Galaxy (M31), is crucial to obtaining
reliable distance determinations. We obtained accurate photometry (in B and V
passbands) of 416 Cepheids in M31 over a five year campaign within a survey
aimed at the detection of eclipsing binaries. The resulting Cepheid sample is
the most complete in M31 and has almost the same period distribution as the
David Dunlap Observatory sample in the Milky Way. The large number of epochs
(~250 per filter) has permitted the characterisation of the pulsation modes of
356 Cepheids, with 281 of them pulsating in the fundamental mode and 75 in the
first overtone. The period-luminosity relationship of the fundamental mode
Cepheids has been studied and a new approach has been used to estimate the
effect of blending. We find that the blending contribution is as important as
the metallicity correction when computing Cepheid distance determinations to
M31 (~0.1 mag). Since large amplitude Cepheids are less affected by blending,
we have used those with an amplitude A_V>0.8 mag to derive a distance to M31 of
(m-M)_0=24.32+/-0.12 mag.Comment: 10 pages, 9 figures; accepted for publication in A&
Population genomics of the Asian tiger mosquito, Aedes albopictus. Insights into the recent worldwide invasion
Aedes albopictus, the “Asian tiger mosquito,” is an aggressive biting mosquito native to Asia that has colonized all continents except Antarctica during the last ~30–40 years. The species is of great public health concern as it can transmit at least 26 arboviruses, including dengue, chikungunya, and Zika viruses. In this study, using double- digest Restriction site-Associated DNA (ddRAD) sequencing, we developed a panel of ~58,000 single nucleotide polymorphisms (SNPs) based on 20 worldwide Ae. albopic-tus populations representing both the invasive and the native range. We used this genomic- based approach to study the genetic structure and the differentiation of Ae. albopictus populations and to understand origin(s) and dynamics of the recent inva-sions. Our analyses indicated the existence of two major genetically differentiated population clusters, each one including both native and invasive populations. The de-tection of additional genetic structure within each major cluster supports that these SNPs can detect differentiation at a global and local scale, while the similar levels of genomic diversity between native and invasive range populations support the scenario of multiple invasions or colonization by a large number of propagules. Finally, our re-sults revealed the possible source(s) of the recent invasion in Americas, Europe, and Africa, a finding with important implications for vector- control strategies
A 3D Photoionization Model of the Extreme Planetary Nebula NGC 6302
We present a 3D photoionization model of the PN NGC 6302, one of the most
complex objects of its kind. Our Mocassin model is composed of an extremely
dense circumstellar disk and a large pair of diffuse bipolar lobes, a
combination necessary to reproduce the observed spectrum. The masses of these
components gives a total nebular mass of 4.7Mo. Discrepancies between our model
fit and the observations are attributed to complex density inhomogeneities in
the nebula. The potential to resolve such discrepancies with more complex
models is confirmed by a range of models introducing small-scale structures.
Compared to solar abundances He is enhanced by 50%, C is slightly subsolar, O
is solar, and N is enhanced by a factor of 6. These imply a significant 3rd
dredge-up coupled with hot-bottom burning CN-cycle conversion of dredged-up C
to N.
The central star is partly obscured by the edge-on circumstellar disk and its
properties are not well constrained. Emission from a number of high-ionization
`coronal' lines provides constraints on the form of the high-energy ionizing
flux. Using a solar abundance stellar atmosphere we are unable to fit all of
the observed line fluxes, but a substantially better fit was obtained using a
220,000K H-deficient stellar atmosphere with L*=14,300 Lo. The H-deficient
nature of the central star suggests it has undergone a late thermal pulse, and
fits to evolutionary tracks imply a central star mass of 0.73-0.82Mo.
Timescales for these tracks suggest the object left the top of the AGB ~2100
years ago, in agreement with studies of the recent mass-loss event that formed
the bipolar lobes. Based on the modelled nebular and central star masses we
estimate the initial mass of the central star to be 5.5Mo, in agreement with
that derived from evolutionary tracks.
(Abstract truncated)Comment: 23 pages, 8 figures, 10 tables. Accepted for publication in MNRA
AINUR: Atlas of Images of NUclear Rings
We present the most complete atlas of nuclear rings to date. We include 113
rings found in 107 galaxies, six of which are elliptical galaxies, five are
highly inclined disc galaxies, 18 are unbarred disc galaxies, and 78 are barred
disc galaxies. Star-forming nuclear rings occur in 20% of disc galaxies with
types between T=-3 and T=7. We aim to explore possible relationships between
the size and morphology of the rings and various galactic parameters. We
produce colour index and structure maps, as well as Halpha and Paalpha
continuum-subtracted images from HST archival data. We derive ellipticity
profiles from H-band 2MASS images in order to detect bars and find their metric
parameters. We measure the non-axisymmetric torque parameter, Qg, and search
for correlations between bar, ring metric parameters, and Qg.
Our atlas of nuclear rings includes star-forming and dust rings. Nuclear
rings span a range from a few tens of parsecs to a few kiloparsecs in radius.
Star-forming nuclear rings can be found in a wide range of morphological types,
from S0 to Sd, with a peak in the distribution between Sab and Sb, and without
strong preference for barred galaxies. Dust nuclear rings are found in
elliptical and S0 galaxies. For barred galaxies, the maximum radius that a
nuclear ring can reach is a quarter of the bar radius. We found a nearly random
distribution of PA offsets between nuclear rings and bars. There is some
evidence that nuclear ring ellipticity is limited by bar ellipticity. We
confirm that the maximum relative size of a star-forming nuclear ring is
inversely proportional to the non-axisymmetric torque parameter, Qg, and that
the origin of nuclear rings, even the ones in non-barred hosts, are closely
linked to the existence of dynamical resonances.Comment: Accepted for publication in MNRAS. A full resolution version of the
manuscript with high resolution figures can be found at
http://www.iac.es/folleto/research/preprints
A practitioner concept of contemporary creativity
This article reviews conceptualisations from three academic areas: the sociology of art, the psychology of creativity, and research on the cultural and creative industries. These are compared with findings from a critical discursive study with UK practitioners. The meanings and associations these ‘maker artists’ attach to creativity are discussed as a ‘practitioner concept’. For the practitioners, the association of creativity with art carries a promise of transcendence and escape from ordinary life, but also a potential challenge to their own entitlement and claims to a creative status. The article shows, first, that the academic areas utilise different and conflicting conceptualisations and, second, that the practitioner concept is not consistent with any one of these. The article argues that the contemporary celebration of creativity is based on different meanings and unacknowledged conflicts. The article proposes that future social psychological research on creativity requires a more critical approach to the concept
The politics and aesthetics of commemoration: national days in southern Africa
The contributions to the special section in this issue study recent independence celebrations and other national days in South
Africa, Namibia, Zimbabwe, Madagascar and the Democratic Republic of Congo. They explore the role of national days in
state-making and nation-building, and examine the performativity of nationalism and the role of performances in national
festivities. Placing the case studies in a broader, comparative perspective, the introduction first discusses the role of the state in
national celebrations, highlighting three themes: firstly, the political power-play and contested politics of memory involved in
the creation of a country’s festive calendar; secondly, the relationship between state control of national days and civic or
popular participation or contestation; and thirdly, the complex relationship between regional and ethnic loyalties and national
identifications. It then turns to the role of performance and aesthetics in the making of nations in general, and in national
celebrations in particular. Finally, we look at the different formats and meanings of national days in the region and address the
question whether there is anything specific about national days in southern Africa as compared to other parts of the continent
or national celebrations world-wide.Web of Scienc
Cognitive Neuropsychology of HIV-Associated Neurocognitive Disorders
Advances in the treatment of the human immunodeficiency virus (HIV) have dramatically improved survival rates over the past 10 years, but HIV-associated neurocognitive disorders (HAND) remain highly prevalent and continue to represent a significant public health problem. This review provides an update on the nature, extent, and diagnosis of HAND. Particular emphasis is placed on critically evaluating research within the realm of cognitive neuropsychology that aims to elucidate the component processes of HAND across the domains of executive functions, motor skills, speeded information processing, episodic memory, attention/working memory, language, and visuoperception. In addition to clarifying the cognitive mechanisms of HAND (e.g., impaired cognitive control), the cognitive neuropsychology approach may enhance the ecological validity of neuroAIDS research and inform the development of much needed novel, targeted cognitive and behavioral therapies
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