2,886 research outputs found
A strategy towards the extraction of the Sivers function with TMD evolution
The QCD evolution of the unpolarized Transverse Momentum Dependent (TMD)
distribution functions and of the Sivers functions have been discussed in
recent papers. Following such results we reconsider previous extractions of the
Sivers functions from semi-inclusive deep inelastic scattering data and propose
a simple strategy which allows to take into account the Q^2 dependence of the
TMDs in comparison with experimental findings. A clear evidence of the
phenomenological success of the TMD evolution equations is given, mostly, by
the newest COMPASS data off a transversely polarized proton target.Comment: 15 pages, 7 figures, 2 table
Numeracy skills, cognitive reserve, and psychological well-being: What relationship in late adult lifespan?
Background: The capacity of understanding and manipulating numerical stimuli (i.e., numeracy) can impact decision making. This investigation was conducted to examine whether number comprehension and mental calculation predict hedonic (i.e., Scale of Positive and Negative Experience, SPANE) and eudaimonic (i.e., Flourishing Scale) well-being in late adulthood, and whether cognitive reserve (i.e., education, time spent for gardening, and time spent for leisure activities) and non-verbal reasoning predict numeracy skills of old adults. Additionally, the effect of age on numeracy was examined, controlling for the effect of education and cognitive efficiency. Methods: One hundred and fifty-eight (i.e., 65–94 years old) community-dwellers completed a battery of tools assessing numeracy, cognitive and metacognitive efficiency, and psychological well-being. Results: Number comprehension, metacognition, time spent for leisure, and perceived physical health accounted for 23% of the variance in the SPANE condition, whereas metacognition, perceived physical health, time for leisure, and education explained 15% of the variance in the Flourishing condition. Moreover, cognitive reserve assessed in terms of vocabulary and education predicted mental calculation. Finally, aging significantly impacted the mental calculation performance of older participants. Conclusions: These findings suggest that numeracy skills can selectively impact the mental health and daily life of older adults
The Sivers Function from SIDIS Data
We study the Sivers effect in transverse single spin asymmetries (SSA) for
pion and kaon production in Semi-Inclusive Deep Inelastic Scattering (SIDIS)
processes. We perform a fit of A^{sin(phi_h-phi_S)}_UT taking into account the
recent data from HERMES and COMPASS Collaborations, which allow a new
determination of the Sivers distribution functions for quark and anti-quark
with u, d and also s flavours. Estimates for forthcoming SIDIS experiments at
COMPASS and JLab are given.Comment: 4 pages, 1 figure. To appear in the proceedings of the XVI
International Workshop on Deep-Inelastic Scattering and Related Subjects, DIS
2008, London, U.K., 7-11 April 200
The Chemical Composition of an Extrasolar Minor Planet
We report the relative abundances of 17 elements in the atmosphere of the
white dwarf star GD 362, material that, very probably, was contained previously
in a large asteroid or asteroids with composition similar to the Earth/Moon
system. The asteroid may have once been part of a larger parent body not unlike
one of the terrestrial planets of our solar system.Comment: ApJ, in pres
Global properties of dilatonic Gauss-Bonnet black holes
We study the phase space of the spherically symmetric solutions of Einstein
Gauss-Bonnet system nonminimally coupled to a scalar field and show that in
four dimensions the only regular black hole solutions are asymptotically flatComment: 12 pages, plain TeX; v.2: phase space is described in more detai
Marked increase in PROP taste responsiveness following oral supplementation with selected salivary proteins or their related free amino acids
The genetic predisposition to taste 6-n-propylthiouracil (PROP) varies among individuals and is associated with salivary levels of Ps-1 and II-2 peptides, belonging to the basic proline-rich protein family (bPRP). We evaluated the role of these proteins and free amino acids that selectively interact with the PROP molecule, in modulating bitter taste responsiveness. Subjects were classified by their PROP taster status based on ratings of perceived taste intensity for PROP and NaCl solutions. Quantitative and qualitative determinations of Ps-1 and II-2 proteins in unstimulated saliva were performed by HPLC-ESI-MS analysis. Subjects rated PROP bitterness after supplementation with Ps-1 and II-2, and two amino acids (L-Arg and L-Lys) whose interaction with PROP was demonstrated by (1)H-NMR spectroscopy. ANOVA showed that salivary levels of II-2 and Ps-1 proteins were higher in unstimulated saliva of PROP super-tasters and medium tasters than in non-tasters. Supplementation of Ps-1 protein in individuals lacking it in saliva enhanced their PROP bitter taste responsiveness, and this effect was specific to the non-taster group.(1)H-NMR results showed that the interaction between PROP and L-Arg is stronger than that involving L-Lys, and taste experiments confirmed that oral supplementation with these two amino acids increased PROP bitterness intensity, more for L-Arg than for L-Lys. These data suggest that Ps-1 protein facilitates PROP bitter taste perception and identifies a role for free L-Arg and L-Lys in PROP tasting
Detailed compositional analysis of the heavily polluted DBZ white dwarf SDSS J073842.56+183509.06: A window on planet formation?
We present a new model atmosphere analysis of the most metal contaminated
white dwarf known, the DBZ SDSS J073842.56+183509.06. Using new high resolution
spectroscopic observations taken with Keck and Magellan, we determine precise
atmospheric parameters and measure abundances of 14 elements heavier than
helium. We also report new Spitzer mid-infrared photometric data that are used
to better constrain the properties of the debris disk orbiting this star. Our
detailed analysis, which combines data taken from 7 different observational
facilities (GALEX, Gemini, Keck, Magellan, MMT, SDSS and Spitzer) clearly
demonstrate that J0738+1835 is accreting large amounts of rocky
terrestrial-like material that has been tidally disrupted into a debris disk.
We estimate that the body responsible for the photospheric metal contamination
was at least as large Ceres, but was much drier, with less than 1% of the mass
contained in the form of water ice, indicating that it formed interior to the
snow line around its parent star. We also find a correlation between the
abundances (relative to Mg and bulk Earth) and the condensation temperature;
refractory species are clearly depleted while the more volatile elements are
possibly enhanced. This could be the signature of a body that formed in a lower
temperature environment than where Earth formed. Alternatively, we could be
witnessing the remains of a differentiated body that lost a large part of its
outer layers.Comment: 16 pages, 17 figures, accepted for publication in The Astrophysical
Journa
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