To identify changes in incidence, presentation, management and outcome, 670 patients with torsion of the spermatic cord presenting in Bristol between 1960 and 1984 have been reviewed. Among the susceptible population of 150,000, the annual incidence of torsion has increased fourfold from 11.2 cases between 1960 and 1964 to 42.8 cases between 1980 and 1984. Throughout this period greater than 90 per cent of patients have been managed by general surgeons. Patients aged between 12-18 years comprised 62 per cent but 20 per cent were 21 years or older. Torsion was commoner in the cold months, 24 per cent of cases occurring during December and January (chi 2 = 30.26, P less than 0.01). When acute torsion was relieved within 12 h of the onset of symptoms only 4 per cent of affected testes were considered non-viable, but beyond this time 75 per cent of patients received orchidectomy. Overall, 238 of 624 (38 per cent) acutely twisted testes were found to be infarcted at operation, and a further 35 patients (6 per cent) had marked testicular atrophy on review 3 months later. The testicular salvage rate has steadily improved from 45 per cent in the years 1960-64 to 67 per cent in 1980-84. Much of the increased incidence of testicular torsion is likely to reflect a greater awareness of the condition by general practitioners. It has been more than matched by an improvement in testicular salvage rate because of earlier referral.

[1] Risk-based planning offers a robust way to identify strategies that permit adaptive water resources management under climate change. This paper presents a flexible methodology for conducting climate change risk assessments involving reservoir operations. Decision makers can apply this methodology to their systems by selecting future periods and risk metrics relevant to their planning questions and by collectively evaluating system impacts relative to an ensemble of climate projection scenarios (weighted or not). This paper shows multiple applications of this methodology in a case study involving California's Central Valley Project and State Water Project systems. Multiple applications were conducted to show how choices made in conducting the risk assessment, choices known as analytical design decisions, can affect assessed risk. Specifically, risk was reanalyzed for every choice combination of two design decisions: (1) whether to assume climate change will influence flood-control constraints on water supply operations (and how), and (2) whether to weight climate change scenarios (and how). Results show that assessed risk would motivate different planning pathways depending on decision-maker attitudes toward risk (e.g., risk neutral versus risk averse). Results also show that assessed risk at a given risk attitude is sensitive to the analytical design choices listed above, with the choice of whether to adjust flood-control rules under climate change having considerably more influence than the choice on whether to weight climate scenarios.

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In an attempt to explain the oligozoospermia commonly observed after unilateral testicular torsion, 56 patients with acute torsion were investigated prospectively. Blood was taken pre-operatively for antibody studies and a contralateral testicular biopsy was performed at the time of orchiopexy. At review 3 to 6 months post-operatively, late testicular atrophy was assessed and repeat antibody studies were performed together with a hormone profile and seminal analysis. Although the duration of torsion showed a close correlation with the degree of testicular atrophy (P less than 0.001), no such association could be demonstrated between duration of torsion and subsequent sperm concentration. Twenty of 35 patients had histological evidence of a pre-existing partial maturation arrest in spermatogenesis. Fifteen of 19 with the abnormality were oligozoospermic, while all of those with normal testicular histology had a sperm concentration within the normal range. Anti-sperm antibody formation following torsion was minimal and antitestis antibodies were absent. Testes prone to torsion already show impaired spermatogenesis.

BackgroundEvidence regarding the association of the built environment with physical activity is influencing policy recommendations that advocate changing the built environment to increase population-level physical activity. However, to date there has been no rigorous appraisal of the quality of the evidence on the effects of changing the built environment. The aim of this review was to conduct a thorough quantitative appraisal of the risk of bias present in those natural experiments with the strongest experimental designs for assessing the causal effects of the built environment on physical activity.MethodsEligible studies had to evaluate the effects of changing the built environment on physical activity, include at least one measurement before and one measurement of physical activity after changes in the environment, and have at least one intervention site and non-intervention comparison site. Given the large number of systematic reviews in this area, studies were identified from three exemplar systematic reviews; these were published in the past five years and were selected to provide a range of different built environment interventions. The risk of bias in these studies was analysed using the Cochrane Risk of Bias Assessment Tool: for Non-Randomized Studies of Interventions (ACROBAT-NRSI).ResultsTwelve eligible natural experiments were identified. Risk of bias assessments were conducted for each physical activity outcome from all studies, resulting in a total of fifteen outcomes being analysed. Intervention sites included parks, urban greenways/trails, bicycle lanes, paths, vacant lots, and a senior citizen’s centre. All outcomes had an overall critical (n = 12) or serious (n = 3) risk of bias. Domains with the highest risk of bias were confounding (due to inadequate control sites and poor control of confounding variables), measurement of outcomes, and selection of the reported result.ConclusionsThe present review focused on the strongest natural experiments conducted to date. Given this, the failure of existing studies to adequately control for potential sources of bias highlights the need for more rigorous research to underpin policy recommendations for changing the built environment to increase physical activity. Suggestions are proposed for how future natural experiments in this area can be improved.Electronic supplementary materialThe online version of this article (doi:10.1186/s12966-016-0433-3) contains supplementary material, which is available to authorized users.

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Anthropogenic climate change amounts to a rapidly approaching, "new" stressor in the Sacramento-San Joaquin Delta system. In response to California's extreme natural hydroclimatic variability, complex water-management systems have been developed, even as the Delta's natural ecosystems have been largely devastated. Climate change is projected to challenge these management and ecological systems in different ways that are characterized by different levels of uncertainty. For example, there is high certainty that climate will warm by about 2°C more (than late-20th-century averages) by mid-century and about 4°C by end of century, if greenhouse-gas emissions continue their current rates of acceleration. Future precipitation changes are much less certain, with as many climate models projecting wetter conditions as drier. However, the same projections agree that precipitation will be more intense when storms do arrive, even as more dry days will separate storms. Warmer temperatures will likely enhance evaporative demands and raise water temperatures. Consequently, climate change is projected to yield both more extreme flood risks and greater drought risks. Sea level rise (SLR) during the 20th century was about 22 cm, and is projected to increase by at least 3-fold this century. SLR together with land subsidence threatens the Delta with greater vulnerabilities to inundation and salinity intrusion. Effects on the Delta ecosystem that are traceable to warming include SLR, reduced snowpack, earlier snowmelt and larger storm-driven streamflows, warmer and longer summers, warmer summer water temperatures, and water-quality changes. These changes and their uncertainties will challenge the operations of water projects and uses throughout the Delta's watershed and delivery areas. Although the effects of climate change on Delta ecosystems may be profound, the end results are difficult to predict, except that native species will fare worse than invaders. Successful preparation for the coming changes will require greater integration of monitoring, modeling, and decision making across time, variables, and space than has been historically normal.

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