Phase diagram of the lattice Wess-Zumino model from rigorous lower bounds on the energy

We study the lattice N=1 Wess-Zumino model in two dimensions and we construct a sequence $\rho^{(L)}$ of exact lower bounds on its ground state energy density $\rho$, converging to $\rho$ in the limit $L\to\infty$. The bounds $\rho^{(L)}$ can be computed numerically on a finite lattice with $L$ sites and can be exploited to discuss dynamical symmetry breaking. The transition point is determined and compared with recent results based on large-scale Green Function Monte Carlo simulations with good agreement.Comment: 32 pages, 12 figure

Quantum magnetism in two dimensions: From semi-classical N\'eel order to magnetic disorder

This is a review of ground-state features of the s=1/2 Heisenberg antiferromagnet on two-dimensional lattices. A central issue is the interplay of lattice topology (e.g. coordination number, non-equivalent nearest-neighbor bonds, geometric frustration) and quantum fluctuations and their impact on possible long-range order. This article presents a unified summary of all 11 two-dimensional uniform Archimedean lattices which include e.g. the square, triangular and kagome lattice. We find that the ground state of the spin-1/2 Heisenberg antiferromagnet is likely to be semi-classically ordered in most cases. However, the interplay of geometric frustration and quantum fluctuations gives rise to a quantum paramagnetic ground state without semi-classical long-range order on two lattices which are precisely those among the 11 uniform Archimedean lattices with a highly degenerate ground state in the classical limit. The first one is the famous kagome lattice where many low-lying singlet excitations are known to arise in the spin gap. The second lattice is called star lattice and has a clear gap to all excitations. Modification of certain bonds leads to quantum phase transitions which are also discussed briefly. Furthermore, we discuss the magnetization process of the Heisenberg antiferromagnet on the 11 Archimedean lattices, focusing on anomalies like plateaus and a magnetization jump just below the saturation field. As an illustration we discuss the two-dimensional Shastry-Sutherland model which is used to describe SrCu2(BO3)2.Comment: This is now the complete 72-page preprint version of the 2004 review article. This version corrects two further typographic errors (three total with respect to the published version), see page 2 for detail

Psychological distress as predictor of quality of life in men experiencing infertility: a cross-sectional survey

<p>Abstract</p> <p>Background</p> <p>Infertility is associated with impairment in human life. The quality of life (QOL) construct allows measuring the impact of health conditions in a broader way. The study aimed to explore the impact of the psychological distress on QOL's dimensions in men experiencing infertility.</p> <p>Methods</p> <p>162 men were completed a socio-demographic form, SF-36, WHOQOL-BREF, Beck Anxiety Inventory and Beck Depression Inventory. Hierarchical regressions included demographic and clinic variables, and subsequently depression and anxiety were added.</p> <p>Results and Discussion</p> <p>Model 1 was not accurate in predicting QOL. R²values ranged from 0.029 (Social Functioning) to 0.149 (Mental Health). Eight domains were not associated with any of the predictors. In the second model, a R²increase was observed in all domains. R²of QOL scores ranged from .209 (Role Physical) to .406 (Social Functioning). The intensity of the depression was a significant predictor for all outcomes. The load of depression was higher than the ones of the socio-demographic and clinical variables. Anxiety levels have also presented the same effect, but with less intensity.</p> <p>Conclusion</p> <p>Subthreshold depression and anxiety were major predictors of QOL in men experiencing infertility. Health professionals need to include assessment of psychological symptomatology to plan more efficient interventions to infertile patients.</p

Readjusting Our Sporting Sites/Sight: Sportification and the Theatricality of Social Life

This paper points out the potential of using sport for the analysis of society. Cultivated human movement is a specific social and cultural subsystem (involving sport, movement culture and physical culture), yet it becomes a part of wider social discourses by extending some of its characteristics into various other spheres. This process, theorised as sportification, provides as useful concept to examine the permeation of certain phenomena from the area of sport into the social reality outside of sport. In this paper, we investigate the phenomena of sportification which we parallel with visual culture and spectatorship practices in the Renaissance era. The emphasis in our investigation is on theatricality and performativity; particularly, the superficial spectator engagement with modern sport and sporting spectacles. Unlike the significance afforded to visualisation and deeper symbolic interpretation in Renaissance art, contemporary cultural shifts have changed and challenged the ways in which the active and interacting body is positioned, politicised, symbolised and ultimately understood. We suggest here that the ways in which we view sport and sporting bodies within a (post)modern context (particularly with the confounding amalgamations of signs and symbols and emphasis on hyper-realities) has invariably become detached from sports' profound metaphysical meanings and resonance. Subsequently, by emphasising the associations between social theatrics and the sporting complex, this paper aims to remind readers of ways that sport—as a nuanced phenomenon—can be operationalised to help us to contemplate questions about nature, society, ourselves and the complex worlds in which we live