2,239 research outputs found
On the analytical approximation to the GLAP evolution at small x and moderate Q^2
Comparing the numerically evaluated solution to the leading order GLAP
equations with its analytical small-x approximation we have found that in the
domain covered by a large fraction of the HERA data the analytic approximation
has to be augmented by the formally non-leading term which has been usually
neglected. The corrected formula fits the data much better and provides a
natural explanation of some of the deviations from the scaling
observed in the HERA kinematical range.Comment: LaTeX, 13 pages including 6 figures, figure 5 replaced, to appear in
Phys. Lett.
Large-scale study of the NGC 1399 globular cluster system in Fornax
We present a Washington C and Kron-Cousins R photometric study of the
globular cluster system of NGC 1399, the central galaxy of the Fornax cluster.
A large areal coverage of 1 square degree around NGC 1399 is achieved with
three adjoining fields of the MOSAIC II Imager at the CTIO 4-m telescope.
Working on such a large field, we can perform the first indicative
determination of the total size of the NGC 1399 globular cluster system. The
estimated angular extent, measured from the NGC 1399 centre and up to a
limiting radius where the areal density of blue globular clusters falls to 30
per cent of the background level, is 45 +/- 5 arcmin, which corresponds to 220
- 275 kpc at the Fornax distance. The bimodal colour distribution of this
globular cluster system, as well as the different radial distribution of blue
and red clusters, up to these large distances from the parent galaxy, are
confirmed. The azimuthal globular cluster distribution exhibits asymmetries
that might be understood in terms of tidal stripping of globulars from NGC
1387, a nearby galaxy. The good agreement between the areal density profile of
blue clusters and a projected dark-matter NFW density profile is emphasized.Comment: 9 pages, 9 figures. Accepted for publication in A&
The effectiveness of dieldrin for control of the Argentine ant in Western Australia
The results of three experiments to compare insecticides for the eradication of Argentine ants are reported. The areas used for the tests were typical household allotments in Shenton Park, a suburb of Perth, Western Australia. The methods of application of sprays and evaluation of results were the same as described in a previous paper. (Forte & Greaves 1953.
New insecticides for the control of the Argentine ant in Western Australia
The Argentine Ant (Iridomyrmex humilis Mayr), has been the subject of much investigation in Western Australia. Jenkins (1943), Jenkins and Forte (1946, 1951), Jenkins (1948) and Forte (1949) have reported results of extensive work on the control of this pest. The results of the investigations have shown that effective control can be obtained by the use of DDT sprays but that large scale eradication was not possible with DDT
Small Angle Polarization in High Energy P--P Scattering Through Nonperturbative Chiral Symmetry Breaking
We show that a large anomalous contribution due to nonperturbative
instanton-like gluonic field configurations to the axial charge of the proton
implies high-energy spin effects in elastic scattering. This is the same
mechanism which is responsible for anomalous baryon number violation at high
energy in the standard model. We compute the proton polarization due to these
effects and we show that it is proportional to the center-of-mass scattering
angle with a universal (energy-independent) slope of order unity.Comment: (13 pages, 2 figures
Transport of apolipoproteins A-I and A-II by human thoracic duct lymph
The daily transport of human plasma apolipoproteins A-I and A-II, triglyceride, and total cholesterol from the thoracic duct lymph into plasma was measured in 2 subjects before and 3 subjects after renal transplantation. Lymph triglyceride transport was ~83% of the daily ingested fat loads, whereas lymph cholesterol transport was consistently greater than the amount of daily ingested cholesterol. Lymph apolipoprotein transport significantly (P < 0.05) exceeded the predicted apolipoprotein synthesis rate by an average of 659±578 mg/d for apolipoprotein A-I and 109±59 mg/d for apolipoprotein A-II among the 5 subjects. It is estimated that 22-77% (apolipoprotein A-I) and 28-82% (apolipoprotein A-II) of daily total body apolipoprotein synthesis takes place in the intestine. Lymph high density lipoprotein particles are mostly high density lipoprotein(2b) and high density lipoprotein(2a) and have a greater overall relative triglyceride content and a smaller relative cholesteryl ester content when compared with homologous plasma high density lipoproteins. The major quantity of both lymph apolipoprotein A-I (81±8%) and apolipoprotein A-II (90±11%) was found within high density lipoproteins with almost all of the remainder found in chylomicrons and very low density lipoproteins. The combined results are consistent with a major contribution of the intestine to total body synthesis of apolipoprotein A-I and apolipoprotein A-II. An important role of lymph in returning filtered apolipoprotein to plasma in association with high density lipoproteins is proposed. Accompanying the return of filtered apolipoprotein to the plasma is a probable transformation, both in size and composition, of at least some of the lymph high density lipoprotein(2b) and high density lipoprotein(2a) particles into high density lipoprotein3
Nonlinear damage analysis: Postulate and evaluation
The objective of this program is to assess the viability of a damage postulate which asserts that the fatigue resistance curve of a metal is history dependent due to inelastic action. The study focusses on OFE copper because this simple model material accentuates the inelastic action central to the damage postulate. Data relevant to damage evolution and crack initiation are developed via a study of surface topography. The effects of surface layer residual stresses are explored via comparative testing as were the effects in initial prestraining. The results of the study very clearly show the deformation history dependence of the fatigue resistance of OFE copper. Furthermore the concept of deformation history dependence is shown to qualitatively explain the fatigue resistance of all histories considered. Likewise quantitative predictions for block cycle histories are found to accurately track the observed results. In this respect the assertion that damage per cycle for a given level of the damage parameter is deformation history dependent appears to be physically justified
Neural Network Parametrization of Deep-Inelastic Structure Functions
We construct a parametrization of deep-inelastic structure functions which
retains information on experimental errors and correlations, and which does not
introduce any theoretical bias while interpolating between existing data
points. We generate a Monte Carlo sample of pseudo-data configurations and we
train an ensemble of neural networks on them. This effectively provides us with
a probability measure in the space of structure functions, within the whole
kinematic region where data are available. This measure can then be used to
determine the value of the structure function, its error, point-to-point
correlations and generally the value and uncertainty of any function of the
structure function itself. We apply this technique to the determination of the
structure function F_2 of the proton and deuteron, and a precision
determination of the isotriplet combination F_2[p-d]. We discuss in detail
these results, check their stability and accuracy, and make them available in
various formats for applications.Comment: Latex, 43 pages, 22 figures. (v2) Final version, published in JHEP;
Sect.5.2 and Fig.9 improved, a few typos corrected and other minor
improvements. (v3) Some inconsequential typos in Tab.1 and Tab 5 corrected.
Neural parametrization available at http://sophia.ecm.ub.es/f2neura
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