Constraints on the intrinsic charm content of the proton from recent ATLAS data

Constraints on the intrinsic charm probability \wccm = P_{{\mathrm{c}\bar \mathrm{c}} / \mathrm{p}} in the proton are obtained for the first time from LHC measurements. The ATLAS Collaboration data for the production of prompt photons, accompanied by a charm-quark jet in pp collisions at $\sqrt s = 8$ TeV, are used. The upper limit \mbox{\wccm < 1.93~\%} is obtained at the 68~\% confidence level. This constraint is primarily determined from the theoretical scale and systematical experimental uncertainties. Suggestions for reducing these uncertainties are discussed. The implications of intrinsic heavy quarks in the proton for future studies at the LHC are also discussed.Comment: 6 pages, 4 figure

A possible nature of breathing plasmas

A model for "breathing" plasmas observed in the large helical device [Y. Takeiri , Plasma Phys. Controlled Fusion 42, 147 (2000)] is proposed. It takes into account the synergism of radiation losses from both low-Z (carbon, oxygen) and high-Z (iron) impurities in the plasma power balance. (C) 2000 American Institute of Physics. [S1070- 664X(00)01411-7]

Fuel Performance Annual Report for 1979

This annual report, the second in a series, provides a brief description of fuel performance in commercial nuclear power plants. Brief summaries are given of fuel surveillance programs, fuel performance problems, and fuel design changes. References to additional, more detailed, information and related NRC evaluation are provided

On the mutual effect of ion temperature gradient instabilities and impurity peaking in the reversed field pinch

The presence of impurities is considered in gyrokinetic calculations of ion temperature gradient (ITG) instabilities and turbulence in the reversed field pinch device RFX-mod. This device usually exhibits hollow Carbon/Oxygen profiles, peaked in the outer core region. We describe the role of the impurities in ITG mode destabilization, and analyze whether ITG turbulence is compatible with their experimental gradients.Comment: 19 pages, 9 figures, accepted for publication in Plasma Phys. Control. Fusio

Design and construction of new central and forward muon counters for CDF II

New scintillation counters have been designed and constructed for the CDF upgrade in order to complete the muon coverage of the central CDF detector, and to extend this coverage to larger pseudorapidity. A novel light collection technique using wavelength shifting fibers, together with high quality polystyrene-based scintillator resulted in compact counters with good and stable light collection efficiency over lengths extending up to 320 cm. Their design and construction is described and results of their initial performance are reported.Comment: 20 pages, 15 figure

Influence of the radio frequency ponderomotive force on anomalous impurity transport in tokamaks

Trace impurity transport in tokamaks is studied using an electrostatic, collisionless fluid model for ion-temperature-gradient and trapped-electron mode driven turbulence in the presence of radio frequency (rf) fields, and the results are compared with neoclassical predictions. It is shown that the inward impurity convective velocity (pinch) that is usually obtained can be reduced by the rf fields, in particular close to the wave resonance location where the rf ponderomotive force may be significant. However, the impurity diffusivity and convective velocity are usually similarly affected by the ponderomotive force, and hence the steady-state impurity density peaking factor -&#8711;nz/nz is only moderately affected by the rf fields

Cardiomyocyte Ca2+ handling and structure is regulated by degree and duration of mechanical load variation

Cardiac transverse (t)-tubules are altered during disease and may be regulated by stretch-sensitive molecules. The relationship between variations in the degree and duration of load and t-tubule structure remains unknown, as well as its implications for local Ca2+-induced Ca2+ release (CICR). Rat hearts were studied after 4 or 8 weeks of moderate mechanical unloading [using heterotopic abdominal heart–lung trans-plantation (HAHLT)] and 6 or 10 weeks of pressure overloading using thoracic aortic constriction. CICR, cell and t-tubule structure were assessed using confocal-microscopy, patch-clamping and scanning ion conductance microscopy. Moderate unloading was compared with severe unloading [using heart-only transplantation (HAHT)]. Mechanical unloading reduced cardiomyocyte volume in a time-dependent manner. Ca2+ release synchronicity was reduced at 8 weeks moderate unloading only. Ca2+ sparks increased in frequency and duration at 8 weeks of moderate unloading, which also induced t-tubule disorganization. Overloading increased cardiomyocyte volume and disrupted t-tubule mor-phology at 10 weeks but not 6 weeks. Moderate mechanical unloading for 4 weeks had milder effects compared with severe mechanical unloading (37 % reduction in cell volume at 4 weeks compared to 56 % reduction after severe mechanical unloading) and did not cause depres-sion and delay of the Ca2+ transient, increased Ca2+ spark frequency or impaired t-tubule and cell surface structure. These data suggest that variations in chronic mechanical load influence local CICR and t-tubule structure in a time- and degree-dependent manner, and that physiologi-cal states of increased and reduced cell size, without pathological changes are possible

Analytical solution of 1D lattice gas model with infinite number of multiatom interactions

We consider a 1D lattice gas model in which the atoms interact via an infinite number of cluster interactions within contiguous atomic chains plus the next nearest neighbor pairwise interaction. All interactions are of arbitrary strength. An analytical expression for the size distribution of atomic chain lengths is obtained in the framework of the canonical ensemble formalism. Application of the exact solution to the problems of self-assembly and self-organization is briefly discussed.Comment: 12 pages, 3 figure

Ion composition in interchange injection events in Saturn\u27s magnetosphere

Interchange injection events are commonly observed by the Cassini spacecraft in the region between about 6 and 12 Rs (1 Rs = 60,268 km) and even frequently beyond. In this study, 13 examples of interchange injection events are identified in Cassini-Cassini Plasma Spectrometer data under special conditions such that time-of-flight (TOF) mass spectra could be obtained from entirely within the events. Using the TOF data to separate the main ion species H+, H2+, and W+, approximate densities of each species are calculated under the assumption that all distributions were isotropic. The light-ion density ratios, H2+/H+, in the injection events are not discernibly different from those ratios in control intervals from the ambient plasma. However, the water-group ration, W+/H+, is significantly lower than ambient. The comparison of the measured density ratios with the range of values observed throughout Saturn\u27s magnetosphere indicates that the values of W+/H+ that are as low as those observed within the injection events are found primarily beyond L~14 (where L is the equatorial crossing distance, in Saturn radius, of a dipole field line), indicating that the injection events are delivering plasma from the outer magnetosphere at times traveling at least 6 Rs