1,825 research outputs found
Real fields and repeated radical extensions
The main result of this paper is that if E is a field extension of finite odd
degree over a real field Q, and if E is a repeated radical extension of Q, then
every intermediate field is also a repeated radical extension of Q. This paper
also contains a number of other results about repeated radical extensions
Oral health-related behaviours reported by elite and professional athletes
Background In elite sport, the protection of an athlete's health is a priority. However, research indicates a substantial prevalence of oral disease in elite and professional athletes. The challenges to oral health from participation in sport require investigation to identify effective strategies and mitigate risk.
Aim To explore athlete-reported oral health behaviours, risks and potential for behaviour change in a representative sample of elite athletes based in the UK.
Method This was a cross-sectional study. We provided oral health screening for 352 elite and professional athletes from June 2015 to September 2016; 344 athletes also completed a questionnaire.
Results The median age was 25 years (range 18-39) and 236 (67%) were male; 323 (94.2%) said they brush twice daily while 136 (40%) said their most recent dental attendance was within the previous six months. Ninety-seven (28%) would be assessed as high consumers of sugar in their regular diet. The use of sports nutrition products was common with 288 (80%) reporting the use of sports drinks during training or competition but were positive about behaviour changes.
Conclusion Despite reporting positive oral health-related behaviours, athletes have substantial amounts of oral disease. Athletes are willing to consider behaviour change related to daily plaque removal, increased fluoride availability and regular dental visits to improve oral health
Body Composition Relates Poorly to Performance in NCAA Division III Football Players
We assessed body composition (height, body mass, body mass index, body fat by densitometry, fat mass, fat-free mass, and lean/fat ratio) and performance (10- and 40-yd sprints, pro shuttle run, vertical jump, sit and reach, and bench press) in 77 National Collegiate Athletic Association Division III football players. Data were analyzed by position and playing status. Significant differences (p less than or equal to 0.05) were found between positions for all body composition measurements and all performance tests except the sit and reach. Starters outperformed nonstarters in all performance tests except the 10-yd sprint and sit and reach (p less than or equal to 0.05). Correlations (r) for percent body fat and performance tests ranged from 0.52 to 0.70, and common variance with the effects of body mass removed ranged from 8 to 23%. Percent body fat is not closely correlated with results of commonly administered performance tests in Division III football players
A Comparative Study of Magnetic Fields in the Solar Photosphere and Chromosphere at Equatorial and Polar Latitudes
Besides their own intrinsic interest, correct interpretation of solar surface
magnetic field observations is crucial to our ability to describe the global
magnetic structure of the solar atmosphere. Photospheric magnetograms are often
used as lower boundary conditions in models of the corona, but not data from
the nearly force-free chromosphere. National Solar Observatory's (NSO) Synoptic
Optical Long-term Investigations of the Sun VSM (Vector Spectromagnetograph)
produces full-disk line-of-sight magnetic flux images deriving from both
photospheric and chromospheric layers on a daily basis. In this paper, we
investigate key properties of the magnetic field in these two layers using more
than five years of VSM data. We find from near-equatorial measurements that the
east-west inclination angle of most photospheric fields is less than about
12{\deg}, while chromospheric fields expand in all directions to a significant
degree. Using a simple stereoscopic inversion, we find evidence that
photospheric polar fields are also nearly radial but that during 2008 the
chromospheric field in the south pole was expanding superradially. We obtain a
spatially resolved polar photospheric flux distribution up to 80{\deg} latitude
whose strength increases poleward approximately as cosine(colatitude) to the
power 9-10. This distribution would give a polar field strength of 5-6 G. We
briefly discuss implications for future synoptic map construction and modeling
Electricity supply industry modeling for multiple objectives under demand growth uncertainty
Appropriate energy–environment–economic (E3) modelling provides key information for policy makers in the electricity supply industry (ESI) faced with navigating a sustainable development path. Key challenges include engaging with stakeholder values and preferences, and exploring trade-offs between competing objectives in the face of underlying uncertainty. As a case study we represent the South African ESI using a partial equilibrium E3 modelling approach, and extend the approach to include multiple objectives under selected future uncertainties. This extension is achieved by assigning cost penalties to non-cost attributes to force the model's least-cost objective function to better satisfy non-cost criteria. This paper incorporates aspects of flexibility to demand growth uncertainty into each future expansion alternative by introducing stochastic programming with recourse into the model. Technology lead times are taken into account by the inclusion of a decision node along the time horizon where aspects of real options theory are considered within the planning process. Hedging in the recourse programming is automatically translated from being purely financial, to include the other attributes that the cost penalties represent. From a retrospective analysis of the cost penalties, the correct market signals, can be derived to meet policy goal, with due regard to demand uncertainty
Randomised controlled trial of specialist nurse intervention in heart failure
<p>Objectives. To determine whether specialist nurse intervention improves outcome in patients with chronic heart failure.</p>
<p>Design. Randomised controlled trial.</p>
<p>Setting. Acute medical admissions unit in a teaching hospital.</p>
<p>Participants. 165 patients admitted with heart failure due to left ventricular systolic dysfunction. The intervention started before discharge and continued thereafter with home visits for up to 1 year.</p>
<p>Main outcome measures. Time to first event analysis of death from all causes or readmission to hospital with worsening heart failure.</p>
<p>Results. 31 patients (37%) in the intervention group died or were readmitted with heart failure compared with 45 (53%) in the usual care group (hazard ratio=0.61, 95% confidence interval 0.33 to 0.96).Compared with usual care, patients in the intervention group had fewer readmissions for any reason (86 v 114, P=0.018), fewer admissions for heart failure (19 v 45, P<0.001) and spent fewer days in hospital for heart failure (mean 3.43 v 7.46 days, P=0.0051).</p>
<p>Conclusions. Specially trained nurses can improve the outcome of patients admitted to hospital with heart failure.</p>
Ponderal Somatograms Assess Changes in Anthropometric Measurements Over an Academic Year in Division III Collegiate Football Players
Ponderal somatograms evaluate body size and shape by converting muscular (shoulders, chest, biceps, forearm, thigh, calf) and nonmuscular (abdomen, hips, knee, ankle, wrist) girths into ponderal equivalent (PE) values. Anthropometric measurements, including stature, body mass, girths, and percent body fat by densitometry were collected in 54 Division III football players in preseason camp (fall) and at the beginning (winter) and end (spring) of the team strength and conditioning program. PE values were calculated for each girth as PE, kg = (girth, cm / k) squared x stature, dm, where k = k constant from Behnke\u27s reference man. PE values were compared to body mass to indicate overdevelopment (PE is greater than body mass) and underdevelopment (PE is less than body mass) at specific girth sites. From fall to winter, body mass (+1.6 kg), percent fat (+1.3%), fat mass (+1.6 kg), nonmuscular abdominal and hip girths (+2.1 cm, +1.5 cm), and PE values (+5.3 kg, +2.6 kg) increased significantly (p is less than 0.05). From winter to spring, percent fat (-1.5%), fat mass (-1.4 kg), nonmuscular abdominal girth (-1.0 co), and PE value (-2.5 kg) decreased significantly (p is less than 0.05) from winter to spring. Fat-free mass (+1.5 kg), muscular biceps girth (+0.4 cm), and PE value (+2.6 kg) increased significantly (p is less than 0.05) from winter to spring. Ponderal somatograms muscular components were generally overdeveloped, with the greatest overdevelopment at the biceps in the fall (+14.7 kg), winter (+14.9 kg), and spring (+17.4 kg). Nonmuscular components generally were underdeveloped, except abdomen and hips that were overdeveloped. The abdomen remained the greatest nonmuscular overdevelopment in fall (+6.8 kg), winter (+10.5 kg), and spring (+7.9 kg). Ponderal somatograms provide a relatively simple, practical method to track specific changes in body size and shape over time
Ponderal Somatogram Analysis of Girth Measurements by Position in Division III College Football Players
Ponderal somatograms assessed body compositions in four groups of Division III collegiate football players: offensive line (OL), defensive line (DL), offensive backs (OB), and defensive backs (DB). Ponderal somatograms evaluate body size and shape by converting muscular (shoulders, chest, biceps, forearm, thigh, and calf) and nonmuscular (abdomen, hips knee, ankle, and wrist) girths into ponderal equivalent (PE) values. Anthropometric measurements, including stature, body mass, girths, and percent body fat by densitometry were collected in 82 players (22 OL, 12 DL, 20 OB, and 28 DB) during preseason camp. PE values were calculated for each girth as PE, kilograms = (girth, cm / k)sq. x stature, decimeters, where k=k constant from Behnke\u27s reference man. PE values were compared to body mass to indicate overdevelopment (PE greater than body mass) and underdevelopment (PE less than body mass). OL was significantly heavier than DL (+15.6 kg), OB (+25.2 kg), and DB (+22.4 kg). OL percent fat as significantly greater than DL (+5.9%), OB (+9.0%), and DB (+9.3%). Similar differences occurred in girths and PE values by position. Muscular components were generally overdeveloped, with the greatest overdevelopment in the biceps (OL + 16.0 kg, DL + 19 kg, OB + 14.2 kg, and DB + 16.2 kg). Nonmuscular abdomen, hips, and knee were generally overdeveloped, with the greatest overdevelopment in the OL abdomen (+19.3 kg). Nonmuscular ankle and wrist were underdeveloped. Ponderal somatograms provide a relatively quick and simple method to translate girth measurements into ponderal equivalent values that seem to be position-specific among offensive and defensive linemen and backs. Somatograms provide an appraisal of body composition that helps coaches and athletes monitor the effectiveness of strength and conditioning programs
Axisymmetric equilibria of a gravitating plasma with incompressible flows
It is found that the ideal magnetohydrodynamic equilibrium of an axisymmetric
gravitating magnetically confined plasma with incompressible flows is governed
by a second-order elliptic differential equation for the poloidal magnetic flux
function containing five flux functions coupled with a Poisson equation for the
gravitation potential, and an algebraic relation for the pressure. This set of
equations is amenable to analytic solutions. As an application, the
magnetic-dipole static axisymmetric equilibria with vanishing poloidal plasma
currents derived recently by Krasheninnikov, Catto, and Hazeltine [Phys. Rev.
Lett. {\bf 82}, 2689 (1999)] are extended to plasmas with finite poloidal
currents, subject to gravitating forces from a massive body (a star or black
hole) and inertial forces due to incompressible sheared flows. Explicit
solutions are obtained in two regimes: (a) in the low-energy regime
, where
, , , and are related to the thermal,
poloidal-current, flow and gravitating energies normalized to the
poloidal-magnetic-field energy, respectively, and (b) in the high-energy regime
. It turns out
that in the high-energy regime all four forces, pressure-gradient,
toroidal-magnetic-field, inertial, and gravitating contribute equally to the
formation of magnetic surfaces very extended and localized about the symmetry
plane such that the resulting equilibria resemble the accretion disks in
astrophysics.Comment: 12 pages, latex, to be published in Geophys. Astrophys. Fluid
Dynamic
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