1,427 research outputs found
Unintegrated parton distributions and inclusive jet production at HERA
We describe how unintegrated parton distributions can be calculated from
conventional integrated distributions. We extend and improve the 'last-step'
evolution approach, and explain why doubly-unintegrated parton distributions
are necessary. We generalise k_t-factorisation to (z,k_t)-factorisation. We
apply the formalism to inclusive jet production in deep-inelastic scattering,
mainly at leading-order, but we also study the extension to next-to-leading
order. We compare the predictions with recent HERA data.Comment: 32 pages, 11 figures. Version to appear in Eur. Phys. J.
Automatic assembly design project 1968/69: report of the control and motivation committee
Methods of control for automatic assembly machines are
surveyed. The control requirements of the versatile
automatic assembly machine are analysed, and the most
practical system is specified and designed in detail
Curvilinear fractures in burned remains: an assessment of the relationship between fracture convexity and fire directionality
Burned remains present a challenge for forensic anthropologists due to the variable nature of fires, the unique way fires impact remains, and the impact of heat changes on the analysis of the remains. A topic of extensive study is the fracture patterns seen in burned remains. Curvilinear fractures are one type of fracture that was originally discussed in the context of studying the preburned state of remains (Baby, 1954; Binford, 1963; Buikstra and Swegle, 1989). These fractures are thought to be created through the kinetic energy generated as muscles shrink and pull on the periosteum, fracturing the bone below (Symes et al., 2008). The convexity of the curvilinear fracture has been theorized to indicate the direction heat moved along bone and, more specifically, points towards the direction of the heat source (Pope, 2007; Symes et al., 2008). To assess the relationship between fracture convexity and fire directionality, the limbs of four sheep were burned in pairs with the dorsal side down and the caudal end away from the origin of the fire. During the burns, video footage was recorded and observation notes were taken. Qualitative observations were summarized using the burn notes, videos, and recovered bones. These observations documented the pattern of limb destruction and movement, color and uniformity of the burn pattern per bone, and all instances of curvilinear fractures and the direction of these fractures. A total of 18 curvilinear fractures were seen on 17 of the 56 bones examined. Of these 18 fractures, 14 were convex distally which was the predicted direction and four were convex proximally. An a posteriori power analysis was conducted and found that a sample size of 32 would be needed for a repetition of this study to have high power and effect size. In this preliminary study, conclusions suggest that curvilinear fractures are not related to fire directionality but likely indicate how heat moves along a bone. With a larger sample size, there are many avenues to further assess how curvilinear fractures are created and what information they can contribute to the anthropological analysis of burned remains
QCD traveling waves at non-asymptotic energies
Using consistent truncations of the BFKL kernel, we derive analytical
traveling-wave solutions of the Balitsky-Kovchegov saturation equation for both
fixed and running coupling. A universal parametrization of the ``interior'' of
the wave front is obtained and compares well with numerical simulations of the
original Balitsky-Kovchegov equation, even at non-asymptotic energies. Using
this universal parametrization, we find evidence for a traveling-wave pattern
of the dipole amplitude determined from the gluon distribution extracted from
deep inelastic scattering data.Comment: 10 pages, 5 figures, minor revision, version to appear in PL
The unintegrated gluon distribution from the CCFM equation
The gluon distribution f(x, k_t^2,mu^2), unintegrated over the transverse
momentum k_t of the gluon, satisfies the angular-ordered CCFM equation which
interlocks the dependence on the scale k_t with the scale \mu of the probe. We
show how, to leading logarithmic accuracy, the equation can be simplified to a
single scale problem. In particular we demonstrate how to determine the
two-scale unintegrated distribution f(x,k_t^2,mu^2) from knowledge of the
integrated gluon obtained from a unified scheme embodying both BFKL and DGLAP
evolution.Comment: 16 pages LaTeX, 3 eps figure
NLO prescription for unintegrated parton distributions
We show how parton distributions unintegrated over the parton transverse
momentum, k_t, may be generated, at NLO accuracy, from the known integrated
(DGLAP-evolved) parton densities determined from global data analyses. A few
numerical examples are given, which demonstrate that sufficient accuracy is
obtained by keeping only the LO splitting functions together with the NLO
integrated parton densities. However, it is important to keep the precise
kinematics of the process, by taking the scale to be the virtuality rather than
the transverse momentum, in order to be consistent with the calculation of the
NLO splitting functions.Comment: 20 pages, 8 figures. v2: version to appear in Eur. Phys. J.
Anterior chamber depth in mice is controlled by several quantitative trait loci
Anterior chamber depth (ACD) is a quantitative trait associated with primary angle closure glaucoma (PACG). Although ACD is highly heritable, known genetic variations explain a small fraction of the phenotypic variability. The purpose of this study was to identify additional ACD-influencing loci using strains of mice. Cohorts of 86 N2 and 111 F2 mice were generated from crosses between recombinant inbred BXD24/TyJ and wild-derived CAST/EiJ mice. Using anterior chamber optical coherence tomography, mice were phenotyped at 10–12 weeks of age, genotyped based on 93 genome-wide SNPs, and subjected to quantitative trait locus (QTL) analysis. In an analysis of ACD among all mice, six loci passed the significance threshold of p = 0.05 and persisted after multiple regression analysis. These were on chromosomes 6, 7, 11, 12, 15 and 17 (named Acdq6, Acdq7, Acdq11, Acdq12, Acdq15, and Acdq17, respectively). Our findings demonstrate a quantitative multi-genic pattern of ACD inheritance in mice and identify six previously unrecognized ACD-influencing loci. We have taken a unique approach to studying the anterior chamber depth phenotype by using mice as genetic tool to examine this continuously distributed trait
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