1,090 research outputs found
Dusty Starbursts and the Growth of Cosmic Structure
Dusty starbursts were more numerous around z~1 than today and appear to be
responsible for the majority of cosmic star formation over the Hubble time. We
suggest that they represent a common phase within galaxies in general which is
triggered by the growth of cosmic structure. We discuss the origin of the
luminosity of luminous infrared galaxies at z~1. Are these galaxies dominated
by star formation or nuclear activity ? What is triggering their strong
activity ? Is it triggered by external interactions or did it happen naturally
within isolated galaxies ? We present HST-ACS high resolution optical images of
luminous infrared galaxies at z~0.7 showing the evolution of the morphology of
these galaxies as a function of infrared luminosity, or star formation rate,
and discuss the effect of the environment on their activity.Comment: 4 pages, 2 figures, to appear in Proceeding of the "Multi-Wavelength
Cosmology" Conference held in Mykonos, Greece, June 2003, ed.M. Plionis
(Kluwer
Drivers of dietary behaviours in women living in urban Africa: a systematic mapping review.
OBJECTIVE: To (i) systematically review the literature to determine the factors influencing diet and dietary behaviour in women living in urban Africa; (ii) present these in a visual map; and (iii) utilize this to identify potentially important areas for future research. DESIGN: Systematic mapping review. The review protocol was registered at PROSPERO (http://www.crd.york.ac.uk/PROSPERO/; registration number CRD42015017749). Six databases were systematically searched, followed by reference and citation searching. Eligibility criteria included women aged 18-70 years living in urban Africa, any design/methodology, exploring any driver, using any measure of dietary behaviour. Quality appraisal occurred parallel with data extraction. Twelve predominantly cross-sectional quantitative studies were included; reported in seventeen publications. Determinants were synthesized narratively and compiled into a map adapted from an existing ecological model based on research in high-income countries. SETTING: Urban Africa. SUBJECTS: African women aged 18-70 years. RESULTS: Determinants significantly associated with unhealthy dietary behaviour ranged from the individual to macro level, comprising negative body image perception, perceptions of insufficient food quantity and poorer quality, poorer food knowledge, skipping meals, snacking less, higher alcohol consumption, unhealthy overall lifestyle, older age, higher socio-economic status, having an education, lower household food expenditure, frequent eating outside the home and media influence. Marital status and strong cultural and religious beliefs were also identified as possible determinants. CONCLUSIONS: Few studies have investigated drivers of dietary behaviours in urban African settings. Predominantly individual-level factors were reported. Gaps in the literature identified a need for research into the neglected areas: social, physical and macro-level drivers of food choice
Social Conformity in Autism
Humans are extremely susceptible to social influence. Here, we examine whether this susceptibility is altered in autism, a condition characterized by social difficulties. Autistic participants (N=22) and neurotypical controls (N=22) completed a memory test of previously seen words and were then exposed to answers supposedly given by four other individuals. Autistic individuals and controls were as likely to alter their judgements to align with inaccurate responses of group members. These changes reflected both temporary judgement changes (public conformity) and long-lasting memory changes (private conformity). Both groups were more susceptible to answers believed to be from other humans than from computer algorithms. Our results suggest that autistic individuals and controls are equally susceptible to social influence when reporting their memories
Gallavotti-Cohen theorem, Chaotic Hypothesis and the zero-noise limit
The Fluctuation Relation for a stationary state, kept at constant energy by a
deterministic thermostat - the Gallavotti-Cohen Theorem -- relies on the
ergodic properties of the system considered. We show that when perturbed by an
energy-conserving random noise, the relation follows trivially for any system
at finite noise amplitude. The time needed to achieve stationarity may stay
finite as the noise tends to zero, or it may diverge. In the former case the
Gallavotti-Cohen result is recovered, while in the latter case, the crossover
time may be computed from the action of `instanton' orbits that bridge
attractors and repellors. We suggest that the `Chaotic Hypothesis' of
Gallavotti can thus be reformulated as a matter of stochastic stability of the
measure in trajectory space. In this form this hypothesis may be directly
tested
Polarizing Double Negation Translations
Double-negation translations are used to encode and decode classical proofs
in intuitionistic logic. We show that, in the cut-free fragment, we can
simplify the translations and introduce fewer negations. To achieve this, we
consider the polarization of the formul{\ae}{} and adapt those translation to
the different connectives and quantifiers. We show that the embedding results
still hold, using a customized version of the focused classical sequent
calculus. We also prove the latter equivalent to more usual versions of the
sequent calculus. This polarization process allows lighter embeddings, and
sheds some light on the relationship between intuitionistic and classical
connectives
Magnetic Field Stimulated Transitions of Excited States in Fast Muonic Helium Ions
It is shown that one can stimulate, by using the present-day laboratory
magnetic fields, transitions between the sub-levels of fast
ions formating in muon catalyzed fusion. Strong fields also cause the
self-ionization from highly excited states of such muonic ions. Both effects
are the consequence of the interaction of the bound muon with the oscillating
field of the Stark term coupling the center-of-mass and muon motions of the
ion due to the non-separability of the collective and internal
variables in this system. The performed calculations show a possibility to
drive the population of the sub-levels by applying a field of a few
, which affects the reactivation rate and is especially important to the
-ray production in muon catalyzed fusion. It is also shown that
the splitting in due to the vacuum polarization slightly
decreases the stimulated transition rates.Comment: 5 figure
Clinical Pharmacology Research Internships at the Interface between Academia and Industry: Students' Perceptions and Scientific Output
The Centre for Human Drug Research (CHDR) is a non-profit clinical research institute at the interface between academia and the pharmaceutical industry. CHDR hosts a research internship programme for undergraduate (bio)medical students. The aim of this study was (i) to investigate the student perceptions of the undergraduate research internship and (ii) to quantify the scientific output related to these internships. We surveyed former interns at the CHDR from the year 2007 to 2014 and quantified their scientific output with a PubMed search. There was a response rate to the survey of 61%, with a good overall rating of the internships. Many students considered their internship at CHDR to be (much) more broad (55%) and with a (much) stricter planning (48%), compared to previous internships at academic research groups. In turn, there were many aspects reported to be similar to academic research internships such as focus on research methodology and 'outcome-drivenness'. Twenty-four per cent of the internships resulted in a co-authorship on papers published in peer-reviewed journals with an average impact factor of 3.3. In conclusion, with appropriate management and supervision, effective research electives are possible in the more commercial environment of a clinical research organization.Pharmacolog
Real Time Turbulent Video Perfecting by Image Stabilization and Super-Resolution
Image and video quality in Long Range Observation Systems (LOROS) suffer from
atmospheric turbulence that causes small neighbourhoods in image frames to
chaotically move in different directions and substantially hampers visual
analysis of such image and video sequences. The paper presents a real-time
algorithm for perfecting turbulence degraded videos by means of stabilization
and resolution enhancement. The latter is achieved by exploiting the turbulent
motion. The algorithm involves generation of a reference frame and estimation,
for each incoming video frame, of a local image displacement map with respect
to the reference frame; segmentation of the displacement map into two classes:
stationary and moving objects and resolution enhancement of stationary objects,
while preserving real motion. Experiments with synthetic and real-life
sequences have shown that the enhanced videos, generated in real time, exhibit
substantially better resolution and complete stabilization for stationary
objects while retaining real motion.Comment: Submitted to The Seventh IASTED International Conference on
Visualization, Imaging, and Image Processing (VIIP 2007) August, 2007 Palma
de Mallorca, Spai
Asymptotic Expansions for the Conditional Sojourn Time Distribution in the -PS Queue
We consider the queue with processor sharing. We study the
conditional sojourn time distribution, conditioned on the customer's service
requirement, in various asymptotic limits. These include large time and/or
large service request, and heavy traffic, where the arrival rate is only
slightly less than the service rate. The asymptotic formulas relate to, and
extend, some results of Morrison \cite{MO} and Flatto \cite{FL}.Comment: 30 pages, 3 figures and 1 tabl
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