672 research outputs found
Higher order parametric X-ray spectra in mosaic graphite and single silicon crystals
We have observed up to eight orders (n) in the spectra of parametric x-radiation, in the range 5-40
keV, produced by the interaction of a 90 Mev electron beam with mosaic graphite and 90 and 35 Mev beams with single silicon crystals. The measured yields and intensity ratios, I(2)/I(n= I), in graphite
are not in agreement with the theory of PXR for mosaic crystals. In comparison, the yield and
ratios of intensities in silicon are close to the predictions of PXR theory for perfect crystals.
The bandwidths of spectral lines measured in both silicon and graphite are in good agreement with
theoretical predictions, and are determined by the angular field of view of the detector.U.S. Department of EnergyDNANaval Postgraduate SchoolContract No. DE-FG03-91ER8109
The teenage religion and values survey in England and Wales : an overview
The Teenage Religion and Values Survey was conducted throughout the 1990s among young people between the ages of 13 and 15 years. A total of 33,982 young people took part in the survey. As the next phase of this research begins for the twenty-first century this paper looks back at the survey conducted in the 1990s and considers two aspects of the research. First, this paper considers the methodology behind designing such a survey. Second, this paper considers some of the insights generated by the survey under five headings: personality, spiritual health, religious affiliation, belonging without believing, and church leaving
An Experimental Investigation of Colonel Blotto Games
"This article examines behavior in the two-player, constant-sum Colonel Blotto game with asymmetric resources in which players maximize the expected number of battlefields won. The experimental results support all major theoretical predictions. In the auction treatment, where winning a battlefield is deterministic, disadvantaged players use a 'guerilla warfare' strategy which stochastically allocates zero resources to a subset of battlefields. Advantaged players employ a 'stochastic complete coverage' strategy, allocating random, but positive, resource levels across the battlefields. In the lottery treatment, where winning a battlefield is probabilistic, both players divide their resources equally across all battlefields." (author's abstract)"Dieser Artikel untersucht das Verhalten von Individuen in einem 'constant-sum Colonel Blotto'-Spiel zwischen zwei Spielern, bei dem die Spieler mit unterschiedlichen Ressourcen ausgestattet sind und die erwartete Anzahl gewonnener Schlachtfelder maximieren. Die experimentellen Ergebnisse bestĂ€tigen alle wichtigen theoretischen Vorhersagen. Im Durchgang, in dem wie in einer Auktion der Sieg in einem Schlachtfeld deterministisch ist, wenden die Spieler, die sich im Nachteil befinden, eine 'Guerillataktik' an, und verteilen ihre Ressourcen stochastisch auf eine Teilmenge der Schlachtfelder. Spieler mit einem Vorteil verwenden eine Strategie der 'stochastischen vollstĂ€ndigen Abdeckung', indem sie zufĂ€llig eine positive Ressourcenmenge auf allen Schlachtfeldern positionieren. Im Durchgang, in dem sich der Gewinn eines Schlachtfeldes probabilistisch wie in einer Lotterie bestimmt, teilen beide Spieler ihre Ressourcen gleichmĂ€Ăig auf alle Schlachtfelder auf." (Autorenreferat
A high-resolution 6.0-megabase transcript map of the type 2 diabetes susceptibility region on human chromosome 20
Recent linkage studies and association analyses indicate the presence of at least one type 2 diabetes susceptibility gene in human chromosome region 20q12-q13.1. We have constructed a high-resolution 6.0-megabase (Mb) transcript map of this interval using two parallel, complementary strategies to construct the map. We assembled a series of bacterial artificial chromosome (BAC) contigs from 56 overlapping BAC clones, using STS/marker screening of 42 genes, 43 ESTs, 38 STSs, 22 polymorphic, and 3 BAC end sequence markers. We performed map assembly with GraphMap, a software program that uses a greedy path searching algorithm, supplemented with local heuristics. We anchored the resulting BAC contigs and oriented them within a yeast artificial chromosome (YAC) scaffold by observing the retention patterns of shared markers in a panel of 21 YAC clones. Concurrently, we assembled a sequence-based map from genomic sequence data released by the Human Genome Project, using a seed-and-walk approach. The map currently provides near-continuous coverage between SGC32867 and WI-17676 (⌠6.0 Mb). EST database searches and genomic sequence alignments of ESTs, mRNAs, and UniGene clusters enabled the annotation of the sequence interval with experimentally confirmed and putative transcripts. We have begun to systematically evaluate candidate genes and novel ESTs within the transcript map framework. So far, however, we have found no statistically significant evidence of functional allelic variants associated with type 2 diabetes. The combination of the BAC transcript map, YAC-to-BAC scaffold, and reference Human Genome Project sequence provides a powerful integrated resource for future genomic analysis of this region
phosphorus and potassium fertilizer effects on alfalfa and soil in a non limited soil
Fertilization strategies for high-yielding alfalfa (Medicago sativa L.) should take in account the increase in soil nutritional status that occurred during the last decades in areas with intensive agricultural use. A field study was conducted at the University of Padova, northeastern Italy, to determine the response of alfalfa yield and nutritive value to various combinations of P and K rates in a soil lacking nutrient deficiency. Alfalfa cultivar Delta was seeded in March 2005 on a silt loam soil having 38 mg kg -1 available P and 178 mg kg -1 exchangeable K. Nine treatments deriving from the combination of three P fertilization rates (0, 100, and 200 kg ha -1 P 2 O 5 ) and three K rates (0, 300, and 600 kg ha -1 K 2 O) were compared in a randomized complete block design. Plots were harvested at bud stage during three growing seasons (2005-2007) and dry matter (DM) yield, forage nutritive value, P and K contents, canopy height, and stem density were measured at each harvest. Soil samples were collected at the end of the research period for determination of available P and exchangeable K. The results demonstrated that P application had no impact on yield and did not interact with K in determining productivity, while K had a positive effect on yield. However, the 300 kg ha -1 K 2 O rate appeared sufficient to maximize yield, without adverse effects on the forage nutritive value. Data from soil analyses showed that alfalfa has a high K uptake even when it is fertilized at high rates
Constraints on the Nucleon Strange Form Factors at Q^2 ~ 0.1 GeV^2
We report the most precise measurement to date of a parity-violating
asymmetry in elastic electron-proton scattering. The measurement was carried
out with a beam energy of 3.03 GeV and a scattering angle =6
degrees, with the result A_PV = -1.14 +/- 0.24 (stat) +/- 0.06 (syst) parts per
million. From this we extract, at Q^2 = 0.099 GeV^2, the strange form factor
combination G_E^s + 0.080 G_M^s = 0.030 +/- 0.025 (stat) +/- 0.006 (syst) +/-
0.012 (FF) where the first two errors are experimental and the last error is
due to the uncertainty in the neutron electromagnetic form factor. This result
significantly improves current knowledge of G_E^s and G_M^s at Q^2 ~0.1 GeV^2.
A consistent picture emerges when several measurements at about the same Q^2
value are combined: G_E^s is consistent with zero while G_M^s prefers positive
values though G_E^s=G_M^s=0 is compatible with the data at 95% C.L.Comment: minor wording changes for clarity, updated references, dropped one
figure to improve focu
Spatial Solitons and Anderson Localization
Stochastic (Anderson) localization is the spatial localization of the
wave-function of quantum particles in random media. We show, that a
corresponding phenomenon can stabilize spatial solitons in optical resonators:
spatial solitons in resonators with randomly distorted mirrors are more stable
than in perfect mirror resonators. We demonstrate the phenomenon numerically,
by investigating solitons in lasers with saturable absorber, and analytically
by deriving and analyzing coupled equations of spatially coherent and
incoherent field components.Comment: submitted to Phys.Rev.
Pharmaceuticals, Personal Care Products, and Endocrine Disruptors in Water: Implications for the Water Industry
Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS
We present the results of a search for new, heavy particles that decay at a
significant distance from their production point into a final state containing
charged hadrons in association with a high-momentum muon. The search is
conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV
and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS
detector operating at the Large Hadron Collider. Production of such particles
is expected in various scenarios of physics beyond the standard model. We
observe no signal and place limits on the production cross-section of
supersymmetric particles in an R-parity-violating scenario as a function of the
neutralino lifetime. Limits are presented for different squark and neutralino
masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final
version to appear in Physics Letters
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
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