Gorenstein homological algebra and universal coefficient theorems

We study criteria for a ring—or more generally, for a small category—to be Gorenstein and for a module over it to be of finite projective dimension. The goal is to unify the universal coefficient theorems found in the literature and to develop machinery for proving new ones. Among the universal coefficient theorems covered by our methods we find, besides all the classic examples, several exotic examples arising from the KK-theory of C*-algebras and also Neeman’s Brown–Adams representability theorem for compactly generated categories

Support for smoke-free policy, and awareness of tobacco health effects and use of smoking cessation therapy in a developing country

BACKGROUND: Preventing an epidemic increase in smoking prevalence is a major challenge for developing countries. Ghana, has maintained a low smoking prevalence despite the presence of cigarette manufacturing for many decades. Some of this success may have been contributed by cultural factors and attitudes. We have studied public awareness of health risks, attitudes to smoke-free policy, tobacco advertising/promotion and other factors in a Ghanaian population sample. METHODS: We used two-stage cluster randomized sampling to study household members aged 14 and over in a representative household sample in the Ashanti Region of Ghana. RESULTS: 6258 people, 88% of those eligible, took part in the study. Knowledge of health risks of smoking and passive smoking was high; radio was the main source of such information. Most people work and/or spend time in places where smoking is permitted. There was very strong support (97%) for comprehensive smoke-free legislation, particularly among Christians and Muslims. Despite the advertising ban, a third of respondents (35%), particularly in urban areas, had noticed advertising of tobacco or tobacco products, on the radio (72%) and television (28%). Among smokers, 76% had attempted to quit in the last 6 months, with the main sources of advice being friends and spouses. Use of nicotine replacement therapy was very rare. Low levels of health awareness were seen in females compared with males (Adjusted Odds Ratio (AOR); 0.51, 95% CI 0.39-0.69, p < 0.001). High levels of health awareness was seen among Traditionalists compared with Christians AOR; 2.16 95% CI 0.79-5.94, p < 0.05) and the relatively well educated (AOR; 1.70 95% CI 1.12-2.58, p < 0.05) and those living in rural areas (AOR 1.46 95% CI 1.14-1.87, p = 0.004). CONCLUSION: Awareness of health risks and support for smoke-free policy are high in Ghana. Exposure to tobacco advertising or promotion is limited and most smokers have tried to quit. Whether these findings are cause or effect of current low smoking prevalence is uncertain

Repaired tetralogy of Fallot: the roles of cardiovascular magnetic resonance in evaluating pathophysiology and for pulmonary valve replacement decision support

Surgical management of tetralogy of Fallot (TOF) results in anatomic and functional abnormalities in the majority of patients. Although right ventricular volume load due to severe pulmonary regurgitation can be tolerated for many years, there is now evidence that the compensatory mechanisms of the right ventricular myocardium ultimately fail and that if the volume load is not eliminated or reduced by pulmonary valve replacement the dysfunction might be irreversible. Cardiovascular magnetic resonance (CMR) has evolved during the last 2 decades as the reference standard imaging modality to assess the anatomic and functional sequelae in patients with repaired TOF. This article reviews the pathophysiology of chronic right ventricular volume load after TOF repair and the risks and benefits of pulmonary valve replacement. The CMR techniques used to comprehensively evaluate the patient with repaired TOF are reviewed and the role of CMR in supporting clinical decisions regarding pulmonary valve replacement is discussed

Characterisation of wind tunnel observed, large-amplitude pitch limit-cycles

A five-degree-of-freedom dynamic wind tunnel rig is used in the observation of large amplitude self-sustaining pitch oscillations of a model aircraft. These oscillations arise during a quasi-steady ramp input to the aircraft model’s elevator surfaces in one-degree-of-freedom pitch mode and in the longitudinal two-degree-of-freedom pitch and heave modes. A mathematical model of the aerodynamics, incorporating dynamic stall, is proposed. The model is coupled to the equations of motion of the rig, which include terms for friction, and fitted to the experimental data. This later process is achieved using continuation and bifurcation analysis and revealed the influence of friction forces on the oscillatory behavior. The quality of the fit and the use of a phenomenological model allows a possible cause for these oscillations to be proposed