564 research outputs found
Head Injury risk and car seat use for children in collisions
Background: Motor vehicle collisions (MVCs) are the leading cause of death for people under the age of 17 years. Almost 80% of rear seat motor vehicle passengers are children. Previous studies have shown that a large fraction of injuries to children in MVCs involved the head and chest. In this study, the hypothesis that children under the age of eight using a forward-facing child restraint system (FFCRS) will have more severe head injuries than children using any other type of restraints in an MVC was tested.
Methods: Several datasets obtained from Transport Canada and Level 1 Pediatric Trauma Centre emergency and admission reports containing collision, occupant, and injury information were combined and trends were analyzed.
Results: Investigations for 42 cases were analyzed (6 fatal / 36 non-fatal injury). Fourteen children had severe head injuries and five of those were fatal. All of those with severe head injuries were using FFCRSs. However, more than half were incorrectly used or installed, or not used at all (8/14).
Discussion & Conclusion: Restraint misuse for child passengers leads to more severe head injuries in MVCs. FFCRSs that are properly used decrease risk of injury and death.
Interdisciplinary Reflection: The findings from this study help to determine why younger children are injured more severely in crashes and whether these injuries are related to the type of restraint system used. This information can be used to create new CRS designs to prevent further injury as well as create treatment plans for the most common youth head injuries
Outpatient management of biliary colic: A prospective observational study of prescribing habits and analgesia effectiveness
AbstractBackgroundUncomplicated biliary colic presents a significant health and financial burden to hospitals and primary care services alike. There is little guidance on the correct analgesia to use on an outpatient basis. This study aimed to evaluate the effectiveness of oral analgesics on biliary colic pain and to explore the prescribing habits of community doctors.MethodsConsecutive patients with ultrasound proven symptomatic gallstones completed a questionnaire recording demographics and symptomatology. Pain was assessed using a visual analogue scale (VAS) based on the Biliary Symptom Score (BSS) to evaluate the effectiveness of various analgesic agents. Local General Practitioners were also surveyed to establish prescribing practices.ResultsCo-Codamol had the highest mean effectiveness VAS score (6.5/10). Patients with increased BMI, short symptom duration and a BSS >70 were most likely to suffer from severe pain. Patients in a subgroup with severe pain were most likely to have their pain reduced by NSAID analgesia compared to no NSAID (OR 2.20, p = 0.027). This effect remained significant upon multivariable regression (OR 2.52, p = 0.018) in a model containing age and NSAIDs. There was wide variation in the prescribing practice of GPs and hospital doctors.ConclusionsThe range of drugs prescribed for biliary colic is extensive with little evidence base. In this study NSAIDs were the most effective analgesia for patients with severe pain. In the absence of contraindications to their use, physician education or guidance emphasizing the benefits of NSAIDs may potentially reduce symptomatic hospital presentation and admissions for biliary colic
Quantum Statistical Mechanics of Nonrelativistic Membranes: Crumpling Transition at Finite Temperature
The effect of quantum fluctuations on a nearly flat, nonrelativistic
two-dimensional membrane with extrinsic curvature stiffness and tension is
investigated. The renormalization group analysis is carried out in first-order
perturbative theory. In contrast to thermal fluctuations, which soften the
membrane at large scales and turn it into a crumpled surface, quantum
fluctuations are found to {\em stiffen} the membrane, so that it exhibits a
Hausdorff dimension equal to two. The large-scale behavior of the membrane is
further studied at finite temperature, where a nontrivial fixed point is found,
signaling a crumpling transition.Comment: RevTex, 9 pages, 1 figur
Derivation of the effective action of a dilute Fermi gas in the unitary limit of the BCS-BEC crossover
The effective action describing the gapless Nambu-Goldstone, or
Anderson-Bogoliubov, mode of a zero-temperature dilute Fermi gas at unitarity
is derived up to next-to-leading order in derivatives from the microscopic
theory. Apart from a next-to-leading order term that is suppressed in the BCS
limit, the effective action obtained in the strong-coupling unitary limit is
proportional to that in the weak-coupling BCS limit.Comment: 13 pages, no figures; v2: discussion of one-dimensional system and
references adde
Model-Based Filtering of Combinatorial Test Suites
International audienceTobias is a combinatorial test generation tool which can efficiently generate a large number of test cases by unfolding a test pattern and computing all combinations of parameters. In this paper, we first propose a model-based testing approach where Tobias test cases are first run on an executable UML/OCL specification. This animation of test cases on a model allows to filter out invalid test sequences produced by blind enumeration, typically the ones which violate the pre-conditions of operations, and to provide an oracle for the valid ones. We then introduce recent extensions of the Tobias tool which support an incremental unfolding and filtering process, and its associated toolset. This allows to address explosive test patterns featuring a large number of invalid test cases, and only a small number of valid ones. For instance, these new constructs could mandate test cases to satisfy a given predicate at some point or to follow a given behavior. The early detection of invalid test cases improves the calculation time of the whole generation and execution process, and helps fighting combinatorial explosion
Clusters in the inner spiral arms of M51: the cluster IMF and the formation history
We study the cluster population in a region of 3.2x3.2 kpc^2 in the inner
spiral arms of the intergacting galaxy M51, at a distance of about 1 to 3 kpc
from the nucleus, based on HST--WFPC2 images taken through five broadband and
two narrowband filters. We found 877 cluster candidates and we derived their
ages, initial masses and extinctions by comparing their energy distribution
with the Starburst99 cluster models. We describe the 3 and 2-dimensional
least-square energy fitting method that was used (3DEF, 2DEF). The lack of
[OIII] emission in even the youngest clusters with strong H-alpha emission,
indicates the absence of the most massive stars and suggests a mass upper limit
of about 25 to 30 solar masses. The mass versus age distribution of the
clusters shows a drastic decrease in the number of clusters with age, which
indicates that cluster disruption is occurring on a timescale of about 10 Myr
for low mass clusters. The cluster initial mass function for clusters younger
than 10 Myr has an exponent of alpha = 2.0 (+- 0.05) We derived the cluster
formation history from clusters with an initial mass larger than 10^4 solar
masses. There is no evidence for a peak in the cluster formation rate within a
factor two at about 200 to 400 Myr ago, i.e. at the time of the interaction
with the companion galaxy NGC 5194.Comment: 15 pages, 15 figures. Accepted for publication by Astronomy and
Astrophysic
A Review of Controlling Motivational Strategies from a Self-Determination Theory Perspective: Implications for Sports Coaches
The aim of this paper is to present a preliminary taxonomy of six controlling strategies, primarily based on the parental and educational literatures, which we believe are employed by coaches in sport contexts. Research in the sport and physical education literature has primarily focused on coachesâ autonomysupportive behaviours. Surprisingly, there has been very little research on the use of controlling strategies. A brief overview of the research which delineates each proposed strategy is presented, as are examples of the potential manifestation of the behaviours associated with each strategy in the context of sports coaching. In line with self-determination theory (Deci & Ryan, 1985; Ryan & Deci, 2002), we propose that coach behaviours employed to pressure or control athletes have the potential to thwart athletesâ feelings of autonomy, competence,and relatedness, which, in turn, undermine athletesâ self-determined motivation and contribute to the development of controlled motives. When athletes feel pressured to behave in a certain way, a variety of negative consequences are expected to ensue which are to the detriment of the athletesâ well-being. The purpose of this paper is to raise awareness and interest in the darker side of sport participation and to offer suggestions for future research in this area
Debris disk size distributions: steady state collisional evolution with P-R drag and other loss processes
We present a new scheme for determining the shape of the size distribution,
and its evolution, for collisional cascades of planetesimals undergoing
destructive collisions and loss processes like Poynting-Robertson drag. The
scheme treats the steady state portion of the cascade by equating mass loss and
gain in each size bin; the smallest particles are expected to reach steady
state on their collision timescale, while larger particles retain their
primordial distribution. For collision-dominated disks, steady state means that
mass loss rates in logarithmic size bins are independent of size. This
prescription reproduces the expected two phase size distribution, with ripples
above the blow-out size, and above the transition to gravity-dominated
planetesimal strength. The scheme also reproduces the expected evolution of
disk mass, and of dust mass, but is computationally much faster than evolving
distributions forward in time. For low-mass disks, P-R drag causes a turnover
at small sizes to a size distribution that is set by the redistribution
function (the mass distribution of fragments produced in collisions). Thus
information about the redistribution function may be recovered by measuring the
size distribution of particles undergoing loss by P-R drag, such as that traced
by particles accreted onto Earth. Although cross-sectional area drops with
1/age^2 in the PR-dominated regime, dust mass falls as 1/age^2.8, underlining
the importance of understanding which particle sizes contribute to an
observation when considering how disk detectability evolves. Other loss
processes are readily incorporated; we also discuss generalised power law loss
rates, dynamical depletion, realistic radiation forces and stellar wind drag.Comment: Accepted for publication by Celestial Mechanics and Dynamical
Astronomy (special issue on EXOPLANETS
Anthropogenic Space Weather
Anthropogenic effects on the space environment started in the late 19th
century and reached their peak in the 1960s when high-altitude nuclear
explosions were carried out by the USA and the Soviet Union. These explosions
created artificial radiation belts near Earth that resulted in major damages to
several satellites. Another, unexpected impact of the high-altitude nuclear
tests was the electromagnetic pulse (EMP) that can have devastating effects
over a large geographic area (as large as the continental United States). Other
anthropogenic impacts on the space environment include chemical release ex-
periments, high-frequency wave heating of the ionosphere and the interaction of
VLF waves with the radiation belts. This paper reviews the fundamental physical
process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure
UV-B absorbing pigments in spores: biochemical responses to shade in a high-latitude birch forest and implications for sporopollenin-based proxies of past environmental change
Current attempts to develop a proxy for Earthâs surface ultraviolet-B (UV-B) flux focus on the organic chemistry of pollen and spores because their constituent biopolymer, sporopollenin, contains UV-B absorbing pigments whose relative abundance may respond to the ambient UV-B flux. Fourier transform infrared (FTIR) microspectroscopy provides a useful tool for rapidly determining the pigment content of spores. In this paper, we use FTIR to detect a chemical response of spore wall UV-B absorbing pigments that correspond with levels of shade beneath the canopy of a high-latitude Swedish birch forest. A 27% reduction in UV-B flux beneath the canopy leads to a significant (p<0.05) 7.3% reduction in concentration of UV-B absorbing compounds in sporopollenin. The field data from this natural flux gradient in UV-B further support our earlier work on sporopollenin-based proxies derived from sedimentary records and herbaria collections
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