1,602 research outputs found
The influence of rifle carriage on the kinetics of human gait
The influence that rifle carriage has on human gait has received little attention in the published literature. Rifle carriage has two main effects, to add load to the anterior of the body and to restrict natural arm swing patterns. Kinetic data were collected from 15 male participants, with 10 trials in each of four experimental conditions. The conditions were: walking without a load (used as a control condition); carrying a lightweight rifle
simulator, which restricted arm movements but applied no additional load; wearing a 4.4 kg diving belt, which allowed arms to move freely; carrying a weighted (4.4 kg)
replica SA80 rifle. Walking speed was fixed at 1.5 m/s (+5%) and data were sampled at 400 Hz. Results showed that rifle carriage significantly alters the ground reaction forces produced during walking, the most important effects being an increase in the impact peak and mediolateral forces. This study suggests that these effects are due to the increased range of motion of the body’s centre of mass caused by the impeding of natural arm swing patterns. The subsequent effect on the potential development of injuries in rifle carriers is unknown
Ozonolysis of surface-adsorbed methoxyphenols: kinetics of aromatic ring cleavage vs. alkene side-chain oxidation
Lignin pyrolysis products, which include a variety of substituted
methoxyphenols, constitute a major component of organics released by biomass
combustion, and may play a central role in the formation of atmospheric brown
carbon. Understanding the atmospheric fate of these compounds upon exposure
to trace gases is therefore critical to predicting the chemical and physical
properties of biomass burning aerosol. We used diffuse reflectance infrared
spectroscopy to monitor the heterogeneous ozonolysis of 4-propylguaiacol,
eugenol, and isoeugenol adsorbed on NaCl and α-Al<sub>2</sub>O<sub>3</sub> substrates.
Adsorption of gaseous methoxyphenols onto these substrates produced near-monolayer surface concentrations of
3 × 10<sup>18</sup> molecules m<sup>−2</sup>. The subsequent dark
heterogeneous ozonolysis of adsorbed 4-propylguaiacol cleaved the aromatic
ring between the methoxy and phenol groups with the product conclusively
identified by GC-MS and <sup>1</sup>H-NMR. Kinetic analysis of eugenol and
isoeugenol dark ozonolysis also suggested the formation of ring-cleaved
products, although ozonolysis of the unsaturated substituent groups forming
carboxylic acids and aldehydes was an order of magnitude faster. Average
uptake coefficients for NaCl-adsorbed methoxyphenols were
γ = 2.3 (± 0.8) × 10<sup>−7</sup> and
2 (± 1) × 10<sup>−6</sup> for ozonolysis of the aromatic ring and
the unsaturated side chain, respectively, and reactions on
α-Al<sub>2</sub>O<sub>3</sub> were approximately two times slower. UV–visible
radiation (λ > 300 nm) enhanced eugenol ozonolysis of the
aromatic ring by a factor of 4(± 1) but had no effect on ozonolysis of
the alkene side chain
Oligomerization of Bacterially Expressed H1N1 Recombinant Hemagglutinin Contributes to Protection Against Viral Challenge
Vaccination is the most effective intervention to prevent influenza and control the spread of the virus. Alternatives are needed to the traditional egg-based vaccine strategy for a more rapid response to new outbreaks. Two different hemagglutinin (HA) fragments (rHA11-326 and rHA153-269) derived from influenza A virus subtype H1N1 were expressed in Escherichia coli and characterized by immunoblot, gel filtration, hemagglutination, and competitive binding assays. rHA11-326 included neutralizing epitopes and the trimerization domain, whereas rHA153-269 included only the head of HA with the neutralizing epitopes. Mice were immunized with rHA11-326 or rHA153-269, and sera were tested for the presence of neutralizing antibodies. Mice were then challenged with H1N1 and infection severity was monitored. rHA11-326 trimerized, whereas rHA153-269 was unable to form oligomers. Both rHA11-326 and rHA153-269 elicited the production of neutralizing antibodies, but only oligomerized rHA11-326 protected against live virus challenges in mice. This study demonstrated that bacterially expressed HA was capable of folding properly and eliciting the production of neutralizing antibodies, and that HA oligomerization contributed to protection against viral challenge. Therefore, prokaryotic-derived vaccine platforms can provide antigenic and structural requirements for viral protection, as well as allow for the rapid and cost-effective incorporation of multiple antigens for broader protection
A note on Makeev's conjectures
A counterexample is given for the Knaster-like conjecture of Makeev for
functions on . Some particular cases of another conjecture of Makeev, on
inscribing a quadrangle into a smooth simple closed curve, are solved
positively
Complex and flexible catabolism in Aromatoleum aromaticum pCyN1
Large quantities of organic matter are continuously deposited, and (a)biotic gradients intersect in the soil-rhizosphere, where biodegradation contributes to the global cycles of elements. The betaproteobacterial genus Aromatoleum comprises cosmopolitan, facultative denitrifying degradation specialists. Aromatoleum aromaticum. pCyN1 stands out for anaerobically decomposing plant-derived monoterpenes in addition to monoaromatic hydrocarbons, polar aromatics and aliphatics. The catabolic network's structure and flexibility in A. aromaticum pCyN1 were studied across 34 growth conditions by superimposing proteome profiles onto the manually annotated 4.37 Mbp genome. Strain pCyN1 employs three fundamentally different enzymes for C-H-bond cleavage at the methyl groups of p-cymene/4-ethyltoluene, toluene and p-cresol respectively. Regulation of degradation modules displayed substrate specificities ranging from narrow (toluene and cyclohexane carboxylate) via medium-wide (one module shared by p-cymene, 4-ethyltoluene, alpha-phellandrene, alpha-terpinene, gamma-terpinene and limonene) to broad (central benzoyl-CoA pathway serving 16 aromatic substrates). Remarkably, three variants of ATP-dependent (class I) benzoyl-CoA reductase and four different beta-oxidation routes establish a degradation hub that accommodates the substrate diversity. The respiratory system displayed several conspicuous profiles, e.g. the presence of nitrous oxide reductase under oxic and of low-affinity oxidase under anoxic conditions. Overall, nutritional versatility in conjunction with network regulation endow A. aromaticum pCyN1 with broad adaptability
Knaster's problem for -symmetric subsets of the sphere
We prove a Knaster-type result for orbits of the group in
, calculating the Euler class obstruction. Among the consequences
are: a result about inscribing skew crosspolytopes in hypersurfaces in , and a result about equipartition of a measures in
by -symmetric convex fans
Target Mass Monitoring and Instrumentation in the Daya Bay Antineutrino Detectors
The Daya Bay experiment measures sin^2 2{\theta}_13 using functionally
identical antineutrino detectors located at distances of 300 to 2000 meters
from the Daya Bay nuclear power complex. Each detector consists of three nested
fluid volumes surrounded by photomultiplier tubes. These volumes are coupled to
overflow tanks on top of the detector to allow for thermal expansion of the
liquid. Antineutrinos are detected through the inverse beta decay reaction on
the proton-rich scintillator target. A precise and continuous measurement of
the detector's central target mass is achieved by monitoring the the fluid
level in the overflow tanks with cameras and ultrasonic and capacitive sensors.
In addition, the monitoring system records detector temperature and levelness
at multiple positions. This monitoring information allows the precise
determination of the detectors' effective number of target protons during data
taking. We present the design, calibration, installation and in-situ tests of
the Daya Bay real-time antineutrino detector monitoring sensors and readout
electronics.Comment: 22 pages, 20 figures; accepted by JINST. Changes in v2: minor
revisions to incorporate editorial feedback from JINS
Recruiting Hard-to-Reach Subjects for Exercise Interventions: A Multi-Centre and Multi-Stage Approach Targeting General Practitioners and Their Community-Dwelling and Mobility-Limited Patients
The general practitioner (GP)’s practice appears to be an ideal venue for recruiting community-dwelling older adults with limited mobility. This study (Current Controlled Trials ISRCTN17727272) aimed at evaluating the recruiting process used for a multi-centre exercise intervention (HOMEfit). Each of six steps resulted in an absolute number of patients (N1–N6). Sex and age (for N4–N6) and reasons for dropping out were assessed. Patient database screening (N1–N3) at 15 GP practices yielded N1 = 5,990 patients aged 70 and above who had visited their GP within the past 6 months, N2 = 5,467 after exclusion of institutionalised patients, N3 = 1,545 patients eligible. Using a pre-defined limitation algorithm in order to conserve the practices’ resources resulted in N4 = 1,214 patients (80.3 ± 5.6 years, 68% female), who were then officially invited to the final assessment of eligibility at the GP’s practice. N5 = 434 patients (79.5 ± 5.4 years, 69% female) attended the practice screening (n = 13 of whom had not received an official invitation). Finally, N6 = 209 (79.8 ± 5.2 years, 74% female) were randomised after they were judged eligible and had given their written informed consent to participate in the randomised controlled trial (overall recruitment rate: 4.4%). The general strategy of utilising a GP’s practice to recruit the target group proved beneficial. The data and experiences presented here can help planners of future exercise-intervention studies
Tensor Regression with Applications in Neuroimaging Data Analysis
Classical regression methods treat covariates as a vector and estimate a
corresponding vector of regression coefficients. Modern applications in medical
imaging generate covariates of more complex form such as multidimensional
arrays (tensors). Traditional statistical and computational methods are proving
insufficient for analysis of these high-throughput data due to their ultrahigh
dimensionality as well as complex structure. In this article, we propose a new
family of tensor regression models that efficiently exploit the special
structure of tensor covariates. Under this framework, ultrahigh dimensionality
is reduced to a manageable level, resulting in efficient estimation and
prediction. A fast and highly scalable estimation algorithm is proposed for
maximum likelihood estimation and its associated asymptotic properties are
studied. Effectiveness of the new methods is demonstrated on both synthetic and
real MRI imaging data.Comment: 27 pages, 4 figure
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