222 research outputs found
Obtaining the basic response pattern of physiological time series data : a comparison of methods
An understanding of the kinetics of physiological variables such as the heart rate or the rate of change of volume of oxygen uptake is fundamental not only to training methodology and competitive success in sport and exercise, but also to our knowledge of cardiovascular health. A correct and efficient means of interpreting and analyzing the data obtained is of vast importance, as exercise testing is routinely used in both of these areas
Ultra Wideband Channel Coefficient Measurements for Detecting Methane Gas in a Multipath Environment
In this paper, an investigation was carried out into the effect of a non-explosive methane gas mixture on various Ultra Wide Band Channel Coefficients. Using simplified apparatus consisting of a rubberized tube (6 mm diameter) connected for significant periods to either a (pressurized) source of mixed Methane and Nitrogen or alternatively to a Nitrogen only source. The tube containing either gas feed was wrapped using two complete turns around a 160mm diameter PVC pipe. Several flows of the mixed gas, containing 2.57% methane, were introduced and flowed through the pipe before being sealed in the tube. Removal of any Methane in the tube was achieved by flushing it with the pure Nitrogen source, initially and in-between samples of the mixed source. A Vector Network Analyser was connected using two identical directional antennas with the wrapped section of tubing placed between the two antennas and the wireless channel coefficients were measured over the Ultra Wide Band frequency span of 0.3GHz to 8GHz. Magnitude differences were taken between the baseline condition (tube flushed out with Nitrogen) and alternatively containing the methane mixture. It was found that consistent and repeatable experiments produced the same trend of differences over the same frequency span. This system based on this approach could thus be used as a simple sensor to detect the ac
MHV Techniques for QED Processes
Significant progress has been made in the past year in developing new `MHV'
techniques for calculating multiparticle scattering amplitudes in Yang-Mills
gauge theories. Most of the work so far has focussed on applications to Quantum
Chromodynamics, both at tree and one-loop level. We show how such techniques
can also be applied to abelian theories such as QED, by studying the simplest
tree-level multiparticle process, e^+e^- to n \gamma. We compare explicit
results for up to n=5 photons using both the Cachazo, Svrcek and Witten `MHV
rules' and the related Britto-Cachazo-Feng `recursion relation' approaches with
those using traditional spinor techniques.Comment: 19 pages, 10 figures. References adde
Geometry and transport in a model of two coupled quadratic nonlinear waveguides
This paper applies geometric methods developed to understand chaos and transport in Hamiltonian systems to the study of power distribution in nonlinear waveguide arrays. The specific case of two linearly coupled X(2) waveguides is modeled and analyzed in terms of transport and geometry in the phase space. This gives us a transport problem in the phase space resulting from the coupling of the two Hamiltonian systems for each waveguide. In particular, the effect of the presence of partial and complete barriers in the phase space on the transfer of intensity between the waveguides is studied, given a specific input and range of material properties. We show how these barriers break down as the coupling between the waveguides is increased and what the role of resonances in the phase space has in this. We also show how an increase in the coupling can lead to chaos and global transport and what effect this has on the intensity
Structural Controls on Shallow Cenozoic Fluid Flow in the Otago Schist, New Zealand
The Otago Schist in the South Island of New Zealand represents an exhumed Mesozoic accretionary prism. Two coastal areas (Akatore Creek and Bruce Rocks) south of Dunedin preserve structural and geochemical evidence for the development of postmetamorphic hydrothermal systems that involved widespread fluid-rock reaction at shallow crustal depths. The Jurassic to Triassic pumpellyite-actinolite (Akatore Creek) to upper greenschist facies (Bruce Rocks) metamorphic fabrics were crosscut by sets of regionally extensive Cretaceous exhumation joints. Many of the joints were subsequently reactivated to form networks of small-displacement (<metres) strike-slip faults containing cemented fault breccias and veins composed of hydrothermal calcite, siderite, and ankerite. Paleostress analysis performed on infrequent fault slickenlines indicates an overall strike-slip paleostress regime and a paleo-Ï1 orientation (azimuth 094°) similar to the contemporary Ï1 orientation in Otago and Canterbury (azimuth c. 110°-120°). High ÎŽ18O values in vein calcite (ÎŽ18OVPDB=21 to 28â°), together with the predominance of Type I calcite twins, suggest that vein formation occurred at low temperatures (<200°C) in the shallow crust and was associated with strongly channelized fluid flow along the joint and fault networks. Mass-balance calculations performed on samples from carbonate alteration zones show that significant mobilisation of elements occurred during fluid flow and fluid-rock reaction. Whole-rock and in situ carbonate 87Sr/86Sr data indicate varying degrees of interaction between the hydrothermal fluids and the host rock schists. Fluids were likely derived from the breakdown of metamorphic Ca-rich mineral phases with low 87Rb in the host schists (e.g., epidote or calcite), as well as more radiogenic components such as mica. Overall, the field and geochemical data suggest that shallow fluid flow in the field areas was channelized along foliation surfaces, exhumation joints, and networks of brittle faults, and that these structures controlled the distribution of fluid-rock reactions and hydrothermal veins. The brittle fault networks and associated hydrothermal systems are interpreted to have formed after the onset of Early Miocene compression in the South Island and may represent the manifestation of fracturing and fluid flow associated with reverse reactivation of regional-scale faults such as the nearby Akatore Fault
New parton distributions in fixed flavour factorization scheme from recent deep-inelastic-scattering data
We present our QCD analysis of the proton structure function
to determine the parton distributions at the next-to-leading order (NLO). The
heavy quark contributions to , with = , have been
included in the framework of the `fixed flavour number scheme' (FFNS). The
results obtained in the FFNS are compared with available results such as the
general-mass variable-flavour-number scheme (GM-VFNS) and other prescriptions
used in global fits of PDFs. In the present QCD analysis, we use a wide range
of the inclusive neutral-current deep-inelastic-scattering (NC DIS) data,
including the most recent data for charm , bottom , longitudinal
structure functions and also the reduced DIS cross sections
from HERA experiments. The most recent HERMES data for
proton and deuteron structure functions are also added. We take into account
ZEUS neutral current DIS inclusive jet cross section data from HERA
together with the recent Tevatron Run-II inclusive jet cross section data from
CDF and D{\O}. The impact of these recent DIS data on the PDFs extracted from
the global fits are studied. We present two families of PDFs, {\tt KKT12} and
{\tt KKT12C}, without and with HERA `combined' data sets on DIS. We
find these are in good agreement with the available theoretical models.Comment: 23 pages, 26 figures and 4 tables. V3: Only few comments and
references added in the replaced version, results unchanged. Code can be
found at http://particles.ipm.ir/links/QCD.ht
âTrial and errorâŠâ, ââŠhappy patientsâ and ââŠan old toy in the cupboardâ: a qualitative investigation of factors that influence practitioners in their prescription of foot orthoses
Background: Foot orthoses are used to manage of a plethora of lower limb conditions. However, whilst the theoretical
foundations might be relatively consistent, actual practices and therefore the experience of patients is likely to be less so.
The factors that affect the prescription decisions that practitioners make about individual patients is unknown and hence
the way in which clinical experience interacts with knowledge from training is not understood. Further, other influences
on orthotic practice may include the adoption (or not) of technology. Hence the aim of this study was to explore, for
the first time, the influences on orthotic practice.
Methods: A qualitative approach was adopted utilising two focus groups (16 consenting participants in total; 15
podiatrists and 1 orthotist) in order to collect the data. An opening question âWhat factors influence your orthotic
practice?â was followed with trigger questions, which were used to maintain focus. The dialogue was recorded
digitally, transcribed verbatim and a thematic framework was used to analyse the data.
Results: There were five themes: (i) influences on current practice, (ii) components of current practice, (iii) barriers
to technology being used in clinical practice, (iv) how technology could enhance foot orthoses prescription and
measurement of outcomes, and (v) how technology could provide information for practitioners and patients. A final
global theme was agreed by the researchers and the participants: âCurrent orthotic practice is variable and does not
embrace technology as it is perceived as being not fit for purpose in the clinical environment. However, practitioners
do have a desire for technology that is usable and enhances patient focussed assessment, the interventions, the clinical
outcomes and the patientâs engagement throughout these processesâ.
Conclusions: In relation to prescribing foot orthoses, practice varies considerably due to multiple influences.
Measurement of outcomes from orthotic practice is a priority but there are no current norms for achieving this.
There have been attempts by practitioners to integrate technology into their practice, but with largely negative
experiences. The process of technology development needs to improve and have a more practice, rather than
technology focus
Cardiac pheochromocytoma involving the left main coronary artery presenting with exertional angina
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26628/1/0000169.pd
QCD
We discuss issues of QCD at the LHC including parton distributions, Monte
Carlo event generators, the available next-to-leading order calculations,
resummation, photon production, small x physics, double parton scattering, and
backgrounds to Higgs production.Comment: 115 pages, Latex, 47 figures, to appear in the Report of the ``1999
CERN Workshop on SM Physics (and more) at the LHC'', S. Catani, M. Dittmar,
D. Soper, W.J. Stirling, S. Tapprogge (convenors
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