2,742 research outputs found
A series of studies on professional rugby league players
Rugby league football is a popular game in Australia, which appears to rely heavily upon strength, power, speed and endurance due to the nature of the phyiscal contacts. In an effort to discern the importance of upper body strength, power speed and endurance to rugby league players a retrospective data analysis was performed. Three areas of investigation were: 1) the testing of upper body physical qualities of strength, power, speed and strength-endurance and their significance to playing status in the elite national first-division (NRL), second-division (SRL) and third-division (CRL), 2) the effect of acute training variable manipulations upon power output and 3) the nature, scope and magnitude of chronic adaptations in strength and power in a multi-year period in professional rugby league players
Neighborhood Criminals and Outsiders in Two Communities: Indications that Criminal Localism Varies
Most research on the mobility of criminal offenders examines distance travelled. This paper examines instead whether neighborhood boundaries are crossed. Comparisons of two neighborhoods in Dayton, Ohio, indicate community variations in criminal mobility. Juveniles from poorer, more transient neighborhoods are surprisingly less likely to stay in the neighborhood to commit their offenses than were adults
Universal analytic properties of noise. Introducing the J-Matrix formalism
We propose a new method in the spectral analysis of noisy time-series data
for damped oscillators. From the Jacobi three terms recursive relation for the
denominators of the Pad\'e Approximations built on the well-known Z-transform
of an infinite time-series, we build an Hilbert space operator, a J-Operator,
where each bound state (inside the unit circle in the complex plane) is simply
associated to one damped oscillator while the continuous spectrum of the
J-Operator, which lies on the unit circle itself, is shown to represent the
noise. Signal and noise are thus clearly separated in the complex plane. For a
finite time series of length 2N, the J-operator is replaced by a finite order
J-Matrix J_N, having N eigenvalues which are time reversal covariant. Different
classes of input noise, such as blank (white and uniform), Gaussian and pink,
are discussed in detail, the J-Matrix formalism allowing us to efficiently
calculate hundreds of poles of the Z-transform. Evidence of a universal
behaviour in the final statistical distribution of the associated poles and
zeros of the Z-transform is shown. In particular the poles and zeros tend, when
the length of the time series goes to infinity, to a uniform angular
distribution on the unit circle. Therefore at finite order, the roots of unity
in the complex plane appear to be noise attractors. We show that the
Z-transform presents the exceptional feature of allowing lossless undersampling
and how to make use of this property. A few basic examples are given to suggest
the power of the proposed method.Comment: 14 pages, 8 figure
Displacement of transport processes on networked topologies
Consider a particle whose position evolves along the edges of a network. One
definition for the displacement of a particle is the length of the shortest
path on the network between the current and initial positions of the particle.
Such a definition fails to incorporate information of the actual path the
particle traversed. In this work we consider another definition for the
displacement of a particle on networked topologies. Using this definition,
which we term the winding distance, we demonstrate that for Brownian particles,
confinement to a network can induce a transition in the mean squared
displacement from diffusive to ballistic behaviour, for long times. A multiple scales approach is used to derive a
macroscopic evolution equation for the displacement of a particle and uncover a
topological condition for whether this transition in the mean squared
displacement will occur. Furthermore, for networks satisfying this topological
condition, we identify a prediction of the timescale upon which the
displacement transitions to long-time behaviour. Finally, we extend the
investigation of displacement on networks to a class of anomalously diffusive
transport processes, where we find that the mean squared displacement at long
times is affected by both network topology and the character of the transport
process.Comment: 22 pages, 8 figure
Critical indices from perturbation analysis of the Callan-Symanzik equation
Recent results giving both the asymptotic behavior and the explicit values of the leading-order perturbation-expansion terms in fixed dimension for the coefficients of the Callan-Symanzik equation are analyzed by the the Borel-Leroy, Padé-approximant method for the n-component φ^4 model. Estimates of the critical exponents for these models are obtained for n=0, 1, 2, and 3 in three dimensions with a typical accuracy of a few one thousandths. In two dimensions less accurate results are obtained
Relativistic Electron Losses in the Outer Radiation Belts
Relativistic electrons in the magnetosphere are both energized and lost via their interaction with plasma waves such as whister chorus, plasmaspheric hiss and EMIC waves. These waves are usually localized in different regions of the magnetosphere as well as being located either inside or outside the plasmapause. We study relativistic electron losses in the outer radiation belts by characterizing decay times scales at low and high altitudes and their relationship to microbursts. We use data collected by SAMPEX, a low Earth orbiting spacecraft in a highly inclined polar orbit and the HEO spacecraft in a high altitude Molniya orbit. The sensors onboard these spacecraft measure electrons of energies > 0.6 MeV, > 1 MeV, > 3 MeV, 2-6 MeV, 3-16 MeV. High time resolution data enable identifying and characterizing electron microbursts observed at low altitudes
A new common functional coding variant at the DDC gene change renal enzyme activity and modify renal dopamine function.
The intra-renal dopamine (DA) system is highly expressed in the proximal tubule and contributes to Na+ and blood pressure homeostasis, as well as to the development of nephropathy. In the kidney, the enzyme DOPA Decarboxylase (DDC) originating from the circulation. We used a twin/family study design, followed by polymorphism association analysis at DDC locus to elucidate heritable influences on renal DA production. Dense single nucleotide polymorphism (SNP) genotyping across the DDC locus on chromosome 7p12 was analyzed by re-sequencing guided by trait-associated genetic markers to discover the responsible genetic variation. We also characterized kinetics of the expressed DDC mutant enzyme. Systematic polymorphism screening across the 15-Exon DDC locus revealed a single coding variant in Exon-14 that was associated with DA excretion and multiple other renal traits indicating pleiotropy. When expressed and characterized in eukaryotic cells, the 462Gln variant displayed lower Vmax (maximal rate of product formation by an enzyme) (21.3 versus 44.9 nmol/min/mg) and lower Km (substrate concentration at which half-maximal product formation is achieved by an enzyme.)(36.2 versus 46.8 μM) than the wild-type (Arg462) allele. The highly heritable DA excretion trait is substantially influenced by a previously uncharacterized common coding variant (Arg462Gln) at the DDC gene that affects multiple renal tubular and glomerular traits, and predicts accelerated functional decline in chronic kidney disease
Non-invasive optical measurement of cerebral critical closing pressure in pediatric hydrocephalus
Hydrocephalus is a common disorder of cerebral spinal fluid (CSF) physiology that results in elevated intracranial pressure (ICP) and progressive expansion of cerebral ventricles.1 It affects 1-2 of every 1000 live births, making it the most common disease treated by pediatric neurosurgeons in the US.1 In roughly half of infants with hydrocephalus, ventricular expansion requires surgical intervention whereby a shunt is placed in the ventricles to divert CSF and relieve elevated ICP. Although timely treatment of elevated ICP is important for brain tissue viability, its implementation is hindered by the lack of tools for non-invasive ICP measurement. This study aims to validate non-invasive intracranial pressure (ICP) assessment with the near-infrared diffuse correlation spectroscopy (DCS) technique in infants with hydrocephalus.
DCS employs near-infrared light to measure local, microvascular cerebral blood flow (CBF) continuously at the bedside. In addition to CBF, a novel approach for measurement of cerebral critical closing pressure (CrCP) based on DCS measurements of pulsatile CBF in arterioles was recently demonstrated.2-4 CrCP, which depends on ICP, defines the arterial blood pressure at which CBF approaches zero. Intraoperative non-invasive CrCP measurements with DCS on the prefrontal cortex were performed concurrently with invasive ICP measurements in 9 infants with hydrocephalus at the Children’s Hospital of Philadelphia. Invasive ICP was measured during surgical shunt placement.
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