248 research outputs found
Shadowing and Absorption Effects on J/psi Production in dA Collisions
We study medium modifications of J/psi production in cold nuclear media in
deuterium-nucleus collisions. We discuss several parameterizations of the
modifications of the parton densities in the nucleus, known as shadowing, an
initial-state effect. We also include absorption of the produced J/psi by
nucleons, a final-state effect. Both spatially homogeneous and inhomogeneous
shadowing and absorption are considered. We use the number of binary
nucleon-nucleon collisions as a centrality measure. Results are presented for
d+Au collisions at sqrt{S_{NN}} = 200 GeV and for d+Pb collisions at
sqrt{S_{NN}} = 6.2 TeV. To contrast the centrality dependence in pA and dA
collisions, we also present pPb results at sqrt{S_{NN}} = 8.8 TeV.Comment: 22 pages, 11 figures, uses revte
The dawn phenomenon in type 2 diabetes: How to assess it in clinical practice?
International audienceAIM : The study was aimed at determining whether the dawn phenomenon in type 2 diabetes (T2D) can be predicted and quantified using simple and easily accessible glucose determinations.METHODS : A total of 210 non-insulin-treated persons with T2D underwent continuous glucose monitoring (CGM). The dawn phenomenon was quantified as the absolute increment from the nocturnal glucose nadir to the pre-breakfast value (Δdawn, mg/dL). Pre-lunch (preL) and pre-dinner (preD) glucose, and their averaged values (preLD), were compared with the nocturnal nadir. These pre-meal values were subtracted from the pre-breakfast values. The differences obtained (Δpre-mealL, Δpre-meal D and Δpre-meal LD) were correlated with Δdawn values. The receiver operating characteristic (ROC) curve was used to select the optimal Δpre-meal value that best predicted a dawn phenomenon, set at a threshold of 20mg/dL.RESULTS : All pre-meal glucose levels and differences from pre-breakfast values (Δpre-meal) significantly correlated (P<0.0001) with the nocturnal nadir and Δdawn values, respectively. The strongest correlations were observed for the parameters averaged at preL and preD time points: r=0.83 for preLD and r=0.58 for Δpre-meal LD. ROC curve analysis indicated that the dawn phenomenon at a threshold of 20mg/dL can be significantly predicted by a Δpre-meal LD cut off value of 10mg/dL. The relationship between Δdawn (Y, mg/dL) and Δpre-meal LD (X, mg/dL) was Y=0.49 X+15.CONCLUSION : The self-monitoring of preprandial glucose values at the three main mealtimes can predict the presence/absence of the dawn phenomenon, and permits reliable assessment of its magnitude without requiring continuous overnight glucose monitoring
Color Screening and the Suppression of the Charmonium State Yield in Nuclear Reactions
We discuss the new data for the production of the meson in pA
collisions at 450 GeV at CERN-SPS (of the NA50-collaboration) [1]. We extract
from the CERN data mb under the assumption that the
is produced as a result of the space-time evolution of a point-like
pair which expands with time to the full size of the charmonium
state. In the analysis we assume the existence of a relationship between the
distribution of color in a hadron and the cross section of its interaction with
a nucleon. However, our result is rather sensitive to the pattern of the
expansion of the wave packet and significantly larger values of are not ruled out by the data. We show that recent CERN data confirm the
suggestion of [2] that color fluctuations of the strengths in
charmonium-nucleon interaction are the major source of suppression of the
yield as observed at CERN in both pA and AA collisions.Comment: 10 pages, 5 figures (one with color
Experimental study of photon beam polarimeter based on nuclear e+e- pair production in an amorphous target
The experimental method of the linearly polarized photons polarimetry,using
incoherent e+e- pair production process has been investigated on the beam of
coherent bremsstrahlung (CB) photons in the energy range of 0.9-1.1 GeV at the
Yerevan synchrotron.Comment: 6 pages (text),10 figure
J/\Psi production, polarization and Color Fluctuations
The hard contributions to the heavy quarkonium-nucleon cross sections are
calculated based on the QCD factorization theorem and the nonrelativistic
quarkonium model. We evaluate the nonperturbative part of these cross sections
which dominates at GeV at the Cern Super Proton
Synchrotron (SPS) and becomes a correction at TeV at
the CERN Large Hadron Collider (LHC). \J production at the CERN SPS is well
described by hard QCD, when the larger absorption cross sections of the
states predicted by QCD are taken into account. We predict an -dependent
polarization of the states. The expansion of small wave packets is
discussed.Comment: 13 pages REVTEX, 1 table, 2 PostScript, corrected some typo
Flare energetics
In this investigation of flare energetics, researchers sought to establish a comprehensive and self-consistent picture of the sources and transport of energy within a flare. To achieve this goal, they chose five flares in 1980 that were well observed with instruments on the Solar Maximum Mission, and with other space-borne and ground-based instruments. The events were chosen to represent various types of flares. Details of the observations available for them and the corresponding physical parameters derived from these data are presented. The flares were studied from two perspectives, the impulsive and gradual phases, and then the results were compared to obtain the overall picture of the energics of these flares. The role that modeling can play in estimating the total energy of a flare when the observationally determined parameters are used as the input to a numerical model is discussed. Finally, a critique of the current understanding of flare energetics and the methods used to determine various energetics terms is outlined, and possible future directions of research in this area are suggested
Cluster coherent potential approximation for electronic structure of disordered alloys
We extend the single-site coherent potential approximation (CPA) to include
the effects of non-local disorder correlations (alloy short-range order) on the
electronic structure of random alloy systems. This is achieved by mapping the
original Anderson disorder problem to that of a selfconsistently embedded
cluster. This cluster problem is then solved using the equations of motion
technique. The CPA is recovered for cluster size , and the disorder
averaged density-of-states (DOS) is always positive definite. Various new
features, compared to those observed in CPA, and related to repeated scattering
on pairs of sites, reflecting the effect of SRO are clearly visible in the DOS.
It is explicitly shown that the cluster-CPA method always yields
positive-definite DOS. Anderson localization effects have been investigated
within this approach. In general, we find that Anderson localization sets in
before band splitting occurs, and that increasing partial order drives a
continuous transition from an Anderson insulator to an incoherent metal.Comment: 7 pages, 6 figures. submitted to PR
Impact of a Community Pharmacist-Delivered Information Program on the Follow-up of Type-2 Diabetic Patients: A Cluster Randomized Controlled Study.
Low-quality communication between patients and care providers and limited patient knowledge of the disease and the therapy are important factors associated with poor glycemic control in patients with type 2 diabetes. We conducted a multicenter study to determine whether structured and tailored information delivered by pharmacists to type 2 diabetic patients could improve patient treatment adherence, hemoglobin A1c (HbA1c) levels and knowledge about diabetes.
One hundred seventy-four pharmacies were randomized to deliver an educational program on diet, drug treatment, disease and complications during three 30-min interviews over a 6-month period, or to provide no intervention, to type 2 diabetic patients treated with oral antidiabetic agents. Medication adherence was assessed by measuring the medication possession ratio and diabetes control by collecting HbA1c values. Levels of patient treatment self-management and disease knowledge were assessed using self-questionnaires.
Three hundred seventy-seven patients were analyzed. The medication possession ratio, already very high at baseline in the intervention (94.8%) and control (92.3%) groups, did not vary significantly after 6 months with no difference between the two groups. Significant decreases in HbA1c were observed in both groups at 6 months (p < 0.001) and 12 months (p < 0.01), with significantly greater changes from baseline in the intervention group than in the control group at 6 months (- 0.5% vs. - 0.2%, p = 0.0047) and 12 months (- 0.6% vs. - 0.2%, p = 0.0057). Patients in the intervention group showed greater improvement in their ability to self-manage treatment (+ 4.86 vs. + 1.58, p = 0.0014) and in the extent of their knowledge about diabetes (+ 0.6 vs. + 0.2, p < 0.01) at 6 months versus baseline compared with the control group.
Tailored information provided by the pharmacist to patients with type 2 diabetes did not significantly improve the already high adherence rates, but was associated with a significant decrease in HbA1c and an improvement of patient knowledge about diabetes.
ISRCTN33776525.
MSD France
Nuclear Broadening Effects on Hard Prompt Photons at Relativistic Energies
We calculate prompt photon production in high-energy nuclear collisions. We
focus on the broadening of the intrinsic transverse momenta of the partons in
the initial state from nuclear effects, and their influence on the prompt
photon p_t distribution. Comparing to WA98 data from Pb+Pb collisions at SPS
energy we find evidence for the presence of nuclear broadening at high p_t in
this hard process. Below p_t=2.7 GeV the photon distribution is due to small
momentum transfer processes. At RHIC energy, the effect of intrinsic transverse
momentum on the spectrum of prompt photons is less prominent. The region
p_t=3-4 GeV would be the most promising for studying the nuclear broadening
effects at that energy. Below p_t=2-3 GeV the contribution from large momentum
transfers flattens out, and we expect that region to be dominated by soft
contributions.Comment: 19 pages, 3 figures, minor changes, a few references adde
The charged-hadron/pion ratio at the Relativistic Heavy Ion Collider
The hadron/pion ratio is calculated in 200 GeV AuAu collisions at
midrapidity, applying pQCD and non-universal transverse-momentum broadening.
Arguments are presented for such non-universality, and the idea is implemented
in a model, which explains the enhancement of the hadron/pion ratio in central
AuAu collisions. The model also describes the qualitative difference between
the recently-measured dAu nuclear enhancement factors for pions and charged
hadrons.Comment: 4 pages, 3 figure
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