16,122 research outputs found
Irreversibility, steady state, and nonequilibrium physics in relativistic heavy ion collisions
Heavy ion collisions at ultrarelativistic energies offer the opportunity to study the irreversibility of multiparticle processes. Together with the many-body decays of resonances, the multiparticle processes cause the system to evolve according to Prigogine s steady states rather than towards statistical equilibrium. These results are general and can be easily checked by any microscopic string-, transport-, or cascade model for heavy ion collisions. The absence of pure equilibrium states sheds light on the di culties of thermal models in describing the yields and spectra of hadrons, especially mesons, in heavy ion collisions at bombarding energies above 10 GeV/nucleon. PACS numbers: 25.75.-q, 05.70.Ln, 24.10.L
Homogeneous nucleation of quark gluon plasma, finite size effects and longlived metastable objects
The general formalism of homogeneous nucleation theory is applied to study the hadronization pattern of the ultra-relativistic quark-gluon plasma (QGP) undergoing a first order phase transition. A coalescence model is proposed to describe the evolution dynamics of hadronic clusters produced in the nucle- ation process. The size distribution of the nucleated clusters is important for the description of the plasma conversion. The model is most sensitive to the initial conditions of the QGP thermalization, time evolution of the energy den- sity, and the interfacial energy of the plasma hadronic matter interface. The rapidly expanding QGP is first supercooled by about T = T Tc = 4 6%. Then it reheats again up to the critical temperature Tc. Finally it breaks up into hadronic clusters and small droplets of plasma. This fast dynamics occurs within the first 5 10 fm/c. The finite size e ects and fluctuations near the critical temperature are studied. It is shown that a drop of longitudinally expanding QGP of the transverse radius below 4.5 fm can display a long-lived metastability. However, both in the rapid and in the delayed hadronization scenario, the bulk pion yield is emitted by sources as large as 3 4.5 fm. This may be detected experimentally both by a HBT interferometry signal and by the analysis of the rapidity distributions of particles in narrow pT -intervals at small |pT | on an event-by-event basis. PACS numbers: 12.38.Mh, 24.10.Pa, 25.75.-q, 64.60.Q
Injury From White Grubs in Iowa
The serious outbreaks of white grubs that have occurred in northeastern Iowa during the past ten years are part of a general outbreak appearing in a number of more or less timbered areas in a belt running from Minnesota and Iowa east to New York, Connecticut and New Jersey. These grubs first appeared in unusual number in 1909, increased in severity in 1912 and reached a climax of injury in 1915. In 1918 the damage was considerably less than in the previous outbreak and it is probable that the parasites and other enemies of the grubs will reduce their numbers to a nearly normal amount by 1921 or 1924 at the latest
Supercooling of rapidly expanding quark-gluon plasma
We reexamine the scenario of homogeneous nucleation of the quark-gluon plasma produced in ultra-relativistic heavy ion collisions. A generalization of the standard nucleation theory to rapidly expanding system is proposed. The nucleation rate is derived via the new scaling parameter Z. It is shown that the size distribution of hadronic clusters plays an important role in the dynamics of the phase transition. The longitudinally expanding system is supercooled to about 3 6%, then it is reheated, and the hadronization is completed within 6 10 fm/c, i.e. 5 10 times faster than it was estimated earlier, in a strongly nonequilibrium way. PACS: 12.38.Mh; 12.39.Ba; 25.75.-q; 64.60.Q
Postmenopausal bone loss : prevention and replacement
Osteoporosis is a skeletal disorder predominantly affecting postmenopausal women. Combination therapy of Carbocalcitonin (Elcatonin) and oral conjugated oestrogens (Premarin) not only prevents postmenopausal bone loss but leads to an increase in bone mass in normal early postmenopausal women. The aims of the study was to investigate the effect of combination therapy. A combination of Elcatonin (Carbo calcitonin) and Premarin was compared to Premarin alone, and to Elcatonin (Carbocalcitonin) alone and all groups were then compared to a control group.peer-reviewe
Rural Water Supplies in South Dakota : Lawrence County
This report on rural water supplies of South Dakota presents data on the types and sources of water supply, exclusive of stream, lake and dam waters in Lawrence County. The publication was prepared by the Works Projects Administration (WPA) as a report on the well survey conducted as WPA Project 665-74-3-126
Rural Water Supplies in South Dakota : Jerauld County
This report on rural water supplies of South Dakota presents data on the types and sources of water supply, exclusive of stream, lake and dam waters in Jerauld County. The publication was prepared by the Works Projects Administration (WPA) as a report on the well survey conducted as WPA Project 665-74-3-126
Rural Water Supplies in South Dakota : Walworth County
This report on rural water supplies of South Dakota presents data on the types and sources of water supply, exclusive of stream, lake and dam waters in Walworth County. The publication was prepared by the Works Projects Administration (WPA) as a report on the well survey conducted as WPA Project 665-74-3-126
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