703 research outputs found
EFFECTS OF LOAD CARRIAGE ON CURVATURE OF THE SPINE
The purpose of this study was to measure the curvature of the spine during load carriage in a rested and mildly fatigued condition. Twelve female subjects walked around an indoor track wearing a 9 kg backpack, in which fifteen spring loaded rods protruded from the back of the pack. The rods were separated by 1.9 cm and were designed to measure the curvature of the spine. The subjects walked for 21 minutes at a rate of 1.79 m/s. Fifteen samples were recorded over 2.5 s at 3 minutes and again at 18 minutes. The means of the two curves were derived from the data to achieve the mean rested and fatigued curves. With fatigue, the cervical to thoracic cavity was thrust forward, causing a significant increase in lordosis of the thoracic to lumbar region. With load carriage, increased lordosis was present to counter balance the weight of the backpack
Emergence of bound states in ballistic magnetotransport of graphene antidots
An experimental method for detection of bound states around an antidot formed
from a hole in a graphene sheet is proposed by measuring the ballistic two
terminal conductances. In particularly, we consider the effect of bound states
formed by magnetic field on the two terminal conductance and show that one can
observe Breit-Wigner like resonances in the conductance as a function of the
Fermi level close to the energies of the bound states. In addition, we develop
a new numerical method in which the computational effort is proportional to the
linear dimensions, instead of the area of the scattering region beeing typical
for the existing numerical recursive Green's function method.Comment: 7 pages, 6 figure
Roper excitation in reactions
We calculate differential cross sections and the spin transfer coefficient
in the reaction for proton
bombarding energies from 1 to 10 GeV and invariant masses spanning
the region of the N(1440) Roper resonance. Two processes --
excitation in the -particle and Roper excitation in the proton -- are
included in an effective reaction model which was shown previously to reproduce
existing inclusive spectra. The present calculations demonstrate that these two
contributions can be clearly distinguished via , even under kinematic
conditions where cross sections alone exhibit no clear peak structure due to
the excitation of the Roper.Comment: 12 pages, 11 ps figures, Late
Generalized gradient approximation for solids and their surfaces
Successful modern generalized gradient approximations (GGA) are biased toward
atomic energies. Restoration of the first-principles gradient expansion for the
exchange energy over a wide range of density gradients eliminates this bias. We
introduce PBEsol, a revised Perdew-Burke-Ernzerhof GGA that improves
equilibrium properties for many densely-packed solids and their surfaces.Comment: 4pages, 2figures,2table
Exchange and Correlation in Open Systems of Fluctuating Electron Number
While the exact total energy of a separated open system varies linearly as a
function of average electron number between adjacent integers, the energy
predicted by semi-local density functional approximations curves upward and the
exact-exchange-only or Hartree-Fock energy downward. As a result, semi-local
density functionals fail for separated open systems of fluctuating electron
number, as in stretched molecular ions A and in solid transition metal
oxides. We develop an exact-exchange theory and an exchange-hole sum rule that
explain these failures and we propose a way to correct them via a local hybrid
functional.Comment: 4 pages, 2 figure
Development of a Synthetic Floral Lure for Pollen Beetles (Coleoptera: Nitidulidae)
Pollen beetles (Coleoptera: Nitidulidae) rank among the most important pests of oilseed rape (Brassica napus). For their timely detection in early spring, yellow sticky or water pan traps are used; however, it has been suggested that the addition of chemical lures to attractive visual cues could improve trap efficacy. During the course of field trials in Hungary, we have developed a 3-component synthetic floral lure consisting of (E)-anethol þ (E)-cinnamyl alcohol þ (E)-cinnamyl acetate, which attracted large numbers of pollen beetles into large capture-capacity fluorescent yellow funnel traps. There was no apparent difference between the pollen beetle species Brassicogethes aeneus F. 1775 (earlier Meligethes aeneus), Brassicogethes viridescens F. 1775, Brassicogethes coracinus Sturm 1845 and Fabogethes nigrescens Sturm 1845 in their responses to the 3-component lure, which can therefore be used to trap all of them. Funnel traps with the new ternary floral lure were more efficient in catching beetles than those with lures containing 2-phenethyl isothiocyanate, a previously described plant-derived attractant for pollen beetles. However, the effect of the
addition of the isothiocyanate to the ternary blend was not completely clear from these experiments and thus requires further studies
Quantum interference structures in the conductance plateaus of gold nanojunctions
The conductance of breaking metallic nanojunctions shows plateaus alternated
with sudden jumps, corresponding to the stretching of stable atomic
configurations and atomic rearrangements, respectively. We investigate the
structure of the conductance plateaus both by measuring the voltage dependence
of the plateaus' slope on individual junctions and by a detailed statistical
analysis on a large amount of contacts. Though the atomic discreteness of the
junction plays a fundamental role in the evolution of the conductance, we find
that the fine structure of the conductance plateaus is determined by quantum
interference phenomenon to a great extent.Comment: 4 pages, 4 figure
Heterogeneity of emergency treatment practices in wheezing preschool children
Aim Our aim was to survey treatment practices used for preschool children with wheezing in emergency rooms (ER) focussing on inhalation device choice and handling, face mask use, salbutamol dosing and written instructions. We sought to assess whether current protocols are in line with published evidence and guidelines. Methods This is a cross-sectional survey done in paediatric ER units located in Finnish municipalities with more than 10 000 inhabitants. Results Of the 100 units contacted, 50% responded. More than 50% of the units used nebulisers. Only 13% of the units administered salbutamol in single puffs. More than 30% of the units lacked criteria on face mask use. Poor co-operation had no effect on the dose of salbutamol in 62% of the units. Ensuring tight mask-to-face seal was included in the training in 20% of the units. A written action plan was provided to the caregivers in 28% of the units. Conclusion ER treatment guidelines for preschool children with wheezing are poorly endorsed. Research is needed to identify approaches to guideline implementation that are specific for primary care. Clinical research should focus on strengthening recommendations that are currently not embraced. ER treatment protocols need to be updated and adherence to guidelines should be re-evaluated.Peer reviewe
Pressure dependence of the spin gap in BaVS_3
We carried out magnetotransport experiments under hydrostatic pressure in
order to study the nature of the metal-insulator transition in BaVS.
Scaling relations for are established and the pressure dependence
of the spin gap is determined. Our new results, in conjunction with a
re-analysis of earlier specific heat and susceptibility data, demonstrate that
the transition is weakly second order. The nature of the phase diagram in the
---- space is discussed.Comment: 5 pages, 5 figures, submitted to PRB Rap. Co
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