4,277 research outputs found
A transition system semantics for the control-driven coordination language Manifold
AbstractCoordination languages are a new class of parallel programming languages which manage the interactions among concurrent programs. Basically, coordination is achieved either by manipulating data values shared among all active processes or by dynamically evolving the interconnections among the processes as a consequence of observations of their state changes. The latter, also called control-driven coordination, is supported by MANIFOLD. We present the formal semantics of a kernel of MANIFOLD, based on a two-level transition system model: the first level is used to specify the ideal behavior of each single component in a MANIFOLD system, whereas the second level captures their interactions. Although we apply our two-level model in this paper to define the semantics of a control-oriented coordination language, this approach is useful for the formal studies of other coordination models and languages as well
The Effect of Lattice Vibrations on Substitutional Alloy Thermodynamics
A longstanding limitation of first-principles calculations of substitutional
alloy phase diagrams is the difficulty to account for lattice vibrations. A
survey of the theoretical and experimental literature seeking to quantify the
impact of lattice vibrations on phase stability indicates that this effect can
be substantial. Typical vibrational entropy differences between phases are of
the order of 0.1 to 0.2 k_B/atom, which is comparable to the typical values of
configurational entropy differences in binary alloys (at most 0.693 k_B/atom).
This paper describes the basic formalism underlying ab initio phase diagram
calculations, along with the generalization required to account for lattice
vibrations. We overview the various techniques allowing the theoretical
calculation and the experimental determination of phonon dispersion curves and
related thermodynamic quantities, such as vibrational entropy or free energy. A
clear picture of the origin of vibrational entropy differences between phases
in an alloy system is presented that goes beyond the traditional bond counting
and volume change arguments. Vibrational entropy change can be attributed to
the changes in chemical bond stiffness associated with the changes in bond
length that take place during a phase transformation. This so-called ``bond
stiffness vs. bond length'' interpretation both summarizes the key phenomenon
driving vibrational entropy changes and provides a practical tool to model
them.Comment: Submitted to Reviews of Modern Physics 44 pages, 6 figure
Spectroscopic Study of IRAS 19285+0517(PDS 100): A Rapidly Rotating Li-Rich K Giant
We report on photometry and high-resolution spectroscopy for IRAS 19285+0517.
The spectral energy distribution based on visible and near-IR photometry and
far-IR fluxes shows that the star is surrounded by dust at a temperature of
250 K. Spectral line analysis shows that the star is a K
giant with a projected rotational velocity = 9 2 km s.
We determined the atmospheric parameters: = 4500 K, log =
2.5, = 1.5 km s, and [Fe/H] = 0.14 dex. The LTE abundance
analysis shows that the star is Li-rich (log (Li) = 2.50.15),
but with essentially normal C, N, and O, and metal abundances. Spectral
synthesis of molecular CN lines yields the carbon isotopic ratio
C/C = 9 3, a signature of post-main sequence evolution and
dredge-up on the RGB. Analysis of the Li resonance line at 6707 \AA for
different ratios Li/Li shows that the Li profile can be fitted best
with a predicted profile for pure Li. Far-IR excess, large Li abundance,
and rapid rotation suggest that a planet has been swallowed or, perhaps, that
an instability in the RGB outer layers triggered a sudden enrichment of Li and
caused mass-loss.Comment: To appear in AJ; 40 pages, 9 figure
Nonlinearity in NS transport: scattering matrix approach
A general formula for the current through a disordered
normal--superconducting junction is derived, which is valid at finite
temperature and includes the full voltage dependence. The result depends on a
multichannel scattering matrix, which describes elastic scattering in the
normal region, and accounts for the Andreev scattering at the NS interface. The
symmetry of the current with respect to sign reversal in the subgap regime is
discussed. The Andreev approximation is used to derive a spectral conductance
formula, which applies to voltages both below and above the gap. In a case
study the spectral conductance formula is applied to the problem of an NINIS
double barrier junction.Comment: 26 pages, 4 Postscript figures, Latex, to be published in Phys. Rev.
GlycA, a novel pro-inflammatory glycoprotein biomarker is associated with mortality:results from the PREVEND study and meta-analysis
BACKGROUND: Chronic diseases are associated with an inflammatory response. We determined the association of two inflammatory markers, GlycA and high-sensitivity C-reactive protein (hsCRP), with overall and cause-specific mortality in a cohort of men and women.METHODS: Cox regression analyses were used to examine associations of GlycA and hsCRP with all-cause, cancer and cardiovascular mortality in 5526 subjects (PREVEND cohort; average follow-up 12.6 years).RESULTS: GlycA was associated with all-cause mortality (n = 838), independent of clinical risk factors and hsCRP (hazard ratio 1.43 [95% confidence interval (CI): 1.09-1.87] for top versus bottom quartiles). For hsCRP, the association with all-cause mortality was nonsignificant after adjustment for GlycA. GlycA and hsCRP were associated with cancer mortality in men (n = 248), but not in women (n = 132). Neither GlycA nor hsCRP was independently associated with cardiovascular mortality (n = 201). In a meta-analysis of seven population-based studies, including 8153 deaths, the pooled multivariable-adjusted relative risk of GlycA for all-cause mortality was 1.74 (95% CI: 1.40-2.17) for top versus bottom quartiles. The association of GlycA with all-cause mortality was somewhat stronger than that of hsCRP. GlycA and hsCRP were not independently associated with cardiovascular mortality. The associations of GlycA and hsCRP with cancer mortality were present in men, but not in women.CONCLUSIONS: GlycA is significantly associated with all-cause mortality. GlycA and hsCRP were each not independently associated with cardiovascular mortality. The association of GlycA and hsCRP with cancer mortality appears to be driven by men.</p
Fibroblast growth factor 23 and new-onset chronic kidney disease in the general population:the Prevention of Renal and Vascular Endstage Disease (PREVEND) study
Background. Fibroblast growth factor 23 (FGF23), a phosphate-regulating hormone that increases early in the course of chronic kidney disease (CKD), is associated with disease progression in patients with established CKD. Here we aimed to investigate the association between plasma FGF23 and new-onset CKD in the general population.Methods. We included 5253 individuals without CKD who participated in the Prevention of Renal and Vascular Endstage Disease study, a prospective, population-based cohort. Multi-variable Cox regression was used to study the association of plasma C-terminal FGF23 with new-onset CKD, defined as a combined endpoint of estimated glomerular filtration rate (eGFR) 30 mg/24 h or both, or with all-cause mortality.Results. The median baseline FGF23 was 68 [interquartile range (IQR) 56-85]RU/mL, eGFR was 9513mL/min/1.73m(2) and UAE was 7.8 (IQR 5.8-11.5) mg/24h. After follow-up of 7.5 (IQR 7.2-8.0) years, 586 participants developed CKD and 214 participants died. A higher FGF23 level was associated with new-onset CKD, independent of risk factors for kidney disease and parameters of bone and mineral homoeostasis {fully adjusted hazard ratio (HR) 1.25 [95% confidence interval (CI) 1.10-1.44] per doubling of FGF23; P=0.001}. In secondary analyses, FGF23 was independently associated with new-onset eGFR 30mg/24h [adjusted HR 1.24 (95% CI 1.06-1.45); P=0.01] individually. A higher FGF23 level was also associated with an increased risk of all-cause mortality [fully adjusted HR 1.30 (95% CI 1.03-1.63); P=0.03].Conclusions. High FGF23 levels are associated with an increased risk of new-onset CKD and all-cause mortality in this prospective population-based cohort, independent of established CKD risk factors.</p
High resolution mapping of a novel late blight resistance gene Rpi-avll, from the wild Bolivian species Solanum avilesii
Both Mexico and South America are rich in Solanum species that might be valuable sources of resistance (R) genes to late blight (Phytophthora infestans). Here, we focus on an R gene present in the diploid Bolivian species S. avilesii. The genotype carrying the R gene was resistant to eight out of 10 Phytophthora isolates of various provenances. The identification of a resistant phenotype and the generation of a segregating population allowed the mapping of a single dominant R gene, Rpi-avl1, which is located in an R gene cluster on chromosome 11. This R gene cluster is considered as an R gene “hot spot”, containing R genes to at least five different pathogens. High resolution mapping of the Rpi-avl1 gene revealed a marker co-segregating in 3890 F1 individuals, which may be used for marker assisted selection in breeding programs and for further cloning of Rpi-avl
The Hyperfine Splittings in Heavy-Light Mesons and Quarkonia
Hyperfine splittings (HFS) are calculated within the Field Correlator Method,
taking into account relativistic corrections. The HFS in bottomonium and the
(q=n,s) mesons are shown to be in full agreement with experiment if a
universal coupling is taken in perturbative spin-spin
potential. It gives MeV, MeV
(), while in bottomonium MeV for and 71.1 MeV for
are obtained; just latter agrees with recent BaBar data. For unobserved
excited states we predict MeV,
MeV, and also MeV,
MeV, MeV. The mass splittings
between , are predicted to be
MeV, which are significantly smaller than in several other studies.Comment: 13 page
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