Studies of iron impurities in YxPr1-xBa2Cu3O7-delta

Pr is the only rare earth which, when substituted for Y in YBa2Cu3O7, significantly alters the superconducting transition temperature T(sub c) without changing the crystal structure. For YxPr1-xBa2Cu3O7-delta with delta approx. equal to 0, T(sub c) is reduced rapidly as x is increased, reaching zero for x about 0.5. For x above 0.5 the compound is antiferromagnetic with a Neel temperature that increases with increasing x, rising to above room temperature for x near 1. A similar behavior is observed when the oxygen deficit delta is increased from zero to 1 with x=0. For the case of Pr substitution, the drop in T(sub c) is believed due to magnetic interactions. For the case of varying delta with x=0, the drop can be attributed to a combination of magnetic interactions, band filling, and changes in crystal structure. To study these effects, the Mossbauer effect of 57 Fe atoms substituted for the Cu atoms has been observed as a function of delta, x, and temperature. The observed spectra are all well described by a two quadrupole-split pairs, a central singlet, and a six-line magnetic hyperfine field pattern. For several Pr compositions both delta and temperature were varied, and the results support the hypothesis that a magnetic interaction exists between the Fe in the Cu lattice and the substitutional Pr atoms

Anisotropic flow of strange particles at RHIC

Space-time picture of the anisotropic flow evolution in Au+Au collisions at BNL RHIC is studied for strange hadrons within the microscopic quark-gluon string model. The directed flow of both mesons and hyperons demonstrates wiggle structure with the universal antiflow slope at |y| < 2 for minimum bias events. This effect increases as the reaction becomes more peripheral. The development of both components of the anisotropic flow is closely related to particle freeze-out. Hadrons are emitted continuously, and different hadronic species are decoupled from the system at different times. These hadrons contribute differently to the formation and evolution of the elliptic flow, which can be decomposed onto three components: (i) flow created by hadrons emitted from the surface at the onset of the collision; (ii) flow produced by jets; (iii) hydrodynamic flow. Due to these features, the general trend in elliptic flow formation is that the earlier mesons are frozen, the weaker their elliptic flow. In contrast, baryons frozen at the end of the system evolution have stronger v2.Comment: proceedings of the conference SQM2004 (September 2004, Cape Town, South Africa

Navigating the grey: Experiences of incremental cannabis reform in Australia

Introduction and Aims: There have been many changes to cannabis laws across the globe, some dramatic but more often incremental. This study explored the experiences after an incremental cannabis law reform in the Australian Capital Territory, Australia. Method: Semi-structured interviews (n = 30) were conducted in March and April 2021, 14 months after the introduction of cannabis law reform, with people aged 18 and over who had grown and/or consumed cannabis in the previous 12 months. Participants were asked about recent and past cannabis use, growing cannabis and changes to their practices after the introduction of the legislation. Results: Incremental cannabis law change resulted in regulatory grey areas. How people interpreted and navigated such grey areas were connected to their relative privileges, circumstances and histories. Those who were highly policed were more likely to experience the grey areas negatively. Those who were not highly policed found the grey areas confusing or ‘half-arse’ (insufficiently executed), but mostly experienced the new laws positively through new cannabis cultivation or perceived reduction in stigma and fear of arrest. Those with self-identified privilege were unconcerned with grey areas of the legislation. Discussion and Conclusion: Incremental policy change can result in grey areas that require some navigation. Vulnerable populations appear less likely to experience the full benefits of such incremental drug law reform. It is vital to attend to the inequities that can arise from incremental law reform so that positive experiences are shared across the population regardless of relative privilege

Doppler-echocardiographic findings in a patient with persisting right ventricular sinusoids

The Doppler-echocardiographic features of persisting right ventricular myocardial sinusoids are presented. An 18-year-old patient with persisting right ventricular sinusoids had undergone comissurotomy for critical pulmonary artery stenosis at the age of 12 months. Follow-up catheterization at the age of 17 years revealed no signs of residual pulmonary artery stenosis, outflow tract obstruction or pulmonary hypertension. No shunt could be documented. High systolic velocity jets within the myocardial sinusoids were recorded by means of continuous-wave Doppler. Pulmonary artery blood flow velocity was recorded mainly consequent to atrial contraction and was reduced during right ventricular ejection period, thus reflecting impaired systolic and diastolic right ventricular functio

Report from Sundance 2006: Religion in Independent Film

This is the report from the Sundance Film Festival 2006