QCD sum rules for D mesons in dense and hot nuclear matter

Open charm mesons (pseudo-scalar and scalar as well as axial-vector and vector) propagating or resting in nuclear matter display an enhanced sensitivity to the chiral condensate. This offers new prospects to seek for signals of chiral restoration, in particular in p-A and p-bar-A reactions as envisaged in first-round experiments by the CBM and PANDA collaborations at FAIR. Weinberg type sum rules for charming chiral partners are presented, and the distinct in-medium modifications of open-charm mesons are discussed. We also address the gluon condensates near Tc and their impact on QCD sum rules.Comment: 6 pages, 7 figures, conference proceeding

Impact of Four-Quark Condensates on In-Medium Effects of Hadrons

Spectral properties of hadrons in nuclear matter are treated in the framework of QCD sum rules. The influence of the ambient strongly interacting medium is encoded in various condensates. Especially, the structure of different four-quark condensates and their density dependencies in light quark systems are exemplified for the omega meson and the nucleon.Comment: Contribution to Quark Confinement and the Hadron Spectrum VII, 02.-07.09.2006, Ponta Delgada, Portuga

Pyric herbivory in the northern mixed grass prairie: testing the use of fire as a land and livestock management tool on rangelands in Saskatchewan

The plant communities of the Great Plains of North America evolved with fire and grazing by bison. With the arrival of Europeans settlers, bison herds were hunted to near extinction, fires were suppressed, and the natural disturbance processes occurring on the prairies were altered. Cattle are now the main source of grazing disturbance on native prairie. Cattle and bison cause different impacts on grasslands and grassland community structure, due to differences in management practices, foraging preferences, and social behaviours. Fire is a natural disturbance which creates a landscape that is variable in vegetation structure, composition, and biomass. Both cattle and bison seek out recently burnt areas, leaving other areas on the landscape to recover from previous grazing. The attraction to burnt areas further promotes a heterogeneous landscape that varies in maturity, structure, and composition. Heterogenous landscapes are important to maintaining an environment that provides habitats to many at-risk grassland species. While the use of prescribed fire as a livestock and land management tool has been study extensively in the in the prairie ecosystems of the United States, few studies have examined the interaction of fire and grazing animals (i.e., pyric herbivory) in the northern mixed grass prairies in Canada. In this study, I examined the short-term effects of two spring prescribed fires on plant community structure in native prairie and tame forage pastures in the northern mixed grass prairie region. I also examined the influence of prescribed fire on cattle movement within these pastures by tracking their movements in the grazing season preceding and following the burns. Prescribed fire reduced total plant and litter biomass, however there were strong climatic influences on vegetation with significant season and annual changes in biomass. Burning homogenized vegetation composition in both pastures in the growing season following the prescribed fires. Finally, I saw a significant increase in cattle visitation to the recently burned areas within the pastures. Pyric herbivory in the northern mixed grass prairies of Canada appears to be a worthwhile land and livestock management tool to promote grassland conservation while maintaining a viable livestock operation

QCD sum rules for D and B mesons in nuclear matter

QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D - D-bar and B - B-bar mesons as a function of the nuclear matter density; extrapolated to saturation density it is in the order of 60 and 130 MeV driven essentially by the condensates , and . The genuine chiral condensate , amplified by heavy-quark masses, enters the Borel transformed sum rules for the mass splitting beyond linear density dependence. Including strange quark condensates reveals a umerically smaller and opposite effect for the Ds - Ds-bar mass splitting.Comment: 16 pages, 8 figures, to be published; a broader range of condensate values is discussed (v2

Introduction of Macromolecules into Bovine Adrenal Medullary Chromaffin Cells and Rat Pheochromocytoma Cells (PC12) by Permeabilization with Streptolysin O: Inhibitory Effect of Tetanus Toxin on Catecholamine Secretion

Conditions are described for controlled plasma membrane permeabilization of rat pheochromocytoma cells (PC12) and cultured bovine adrenal chromaffin cells by Streptolysin O (SLO). The transmembrane pores created by SLO invoke rapid efflux of intracellular 86Rb+ and ATP, and also permit passive diffusion of proteins, including immunoglobulins, into the cells. SLO-permeabilized PC12 cells release [3H]dopamine in response to micromolar concentrations of free Ca2+. Permeabilized adrenal chromaffin cells present a similar exocytotic response to Ca2+ in the presence of Mg2+/ ATP. Permeabilized PC12 cells accumulate antibodies against synaptophysin and calmodulin, but neither antibody reduces the Ca2+-dependent secretory response. Reduced tetanus toxin, although ineffective when applied to intact chromaffin cells, inhibits Ca2+-induced exocytosis by both types of permeabilized cells studied. Omission of dithiothreitol, toxin inactivation by boiling, or preincubation with neutralizing antibodies abolishes the inhibitory effect. The data indicate that plasma membrane permeabilization by Streptolysin O is a useful tool to probe and define cellular components that are involved in the final steps of exocytosis

Creation of model of the photon beam with a treatment planning system PLUNC for ELEKTA Synergy linear accelerator

In the present study, we performed a comparison and selection of the most appropriate treatment plan with an educational treatment planning system PLUNC which was provide recommended absorbed dose of ionizing radiation in tumor volume, and the minimum value of the dose in organs at risk and normal tissues surrounding the tumor. For this reason, was created model of the photon beam for ELEKTA Synergy Linear Accelerator. The treatment plan was developed for patients with rectal cancer. The simulation was performed on the basis of actual dicom - images of the tumor, which was obtained with modern medical equipment (computed tomography Aquilion Toshiba). For checking of the simulated plan quality, reference dose and dose rate measurements were performed. Present study demonstrates the relationship between the dose distributions and selected treatment plan. As result of research, was conducted comparison and analysis of algorithms for dose calculation in tissueequivalent environment with a treatment planning system PLUNC. Was developed methodological guide for work in the PLUNC software. Thereby, educational treatment planning system PLUNC was put into operation

Further Characterization of Dopamine Release by Permeabilized PC 12 Cells

Rat pheochromocytoma cells (PC 12) permeabilized with staphylococcal α-toxin release [3H]dopamine after addition of micromolar Ca2+. This does not require additional Mg2+-ATP (in contrast to bovine adrenal medullary chromaffin cells). We also observed Ca2+-dependent [3H]-dopamine release from digitonin-permeabilized PC 12 cells. Permeabilization with α-toxin or digitonin and stimulation of the cells were done consecutively to wash out endogenous Mg2+-ATP. During permeabilization, ATP was removed effectively from the cytoplasm by both agents but the cells released [3H]dopamine in response to micromolar Ca2+ alone. Replacement by chloride of glutamate, which could sustain mitochondrial ATP production in permeabilized cells, does not significantly alter catecholamine release induced by Ca2+. However, Mg2+ without ATP augments the Ca2+-induced release. The release was unaltered by thiol-, hydroxyl-, or calmodulin-interfering substances. Thus Mg2+-ATP, calmodulin, or proteins containing -SH or -OH groups are not necessary for exocytosis in permeabilized PC 12 cells

Assessing a Hydrodynamic Description for Instabilities in Highly Dissipative, Freely Cooling Granular Gases

An intriguing phenomenon displayed by granular flows and predicted by kinetic-theory-based models is the instability known as particle "clustering," which refers to the tendency of dissipative grains to form transient, loose regions of relatively high concentration. In this work, we assess a modified-Sonine approximation recently proposed [Garz\'o et al., Physica A 376, 94 (2007)] for a granular gas via an examination of system stability. In particular, we determine the critical length scale associated with the onset of two types of instabilities -vortices and clusters- via stability analyses of the Navier-Stokes-order hydrodynamic equations by using the expressions of the transport coefficients obtained from both the standard and the modified-Sonine approximations. We examine the impact of both Sonine approximations over a range of solids fraction \phi <0.2 for small restitution coefficients e=0.25--0.4, where the standard and modified theories exhibit discrepancies. The theoretical predictions for the critical length scales are compared to molecular dynamics (MD) simulations, of which a small percentage were not considered due to inelastic collapse. Results show excellent quantitative agreement between MD and the modified-Sonine theory, while the standard theory loses accuracy for this highly dissipative parameter space. The modified theory also remedies a (highdissipation) qualitative mismatch between the standard theory and MD for the instability that forms more readily. Furthermore, the evolution of cluster size is briefly examined via MD, indicating that domain-size clusters may remain stable or halve in size, depending on system parameters.Comment: 4 figures; to be published in Phys. Rev.