Using particle dispersal models to assist in the conservation and recovery of the overexploited native oyster (Ostrea edulis) in an enclosed sea lough

Oyster populations around the world have seen catastrophic decline which has been largely attributed to overexploitation, disease and pollution. While considerable effort and resources have been implemented into restoring these important environmental engineers, the success of oyster populations is often limited by poor understanding of site-specific dispersal patterns of propagules. Water-borne transport is a key factor controlling or regulating the dispersal of the larval stage of benthic marine invertebrates which have limited mobility. The distribution of the native oyster Ostrea edulis in Strangford Lough, Northern Ireland, together with their densities and population structure at subtidal and intertidal sites has been documented at irregular intervals between 1997 and 2013. This paper revisits this historical data and considers whether different prevailing environmental conditions can be used to explain the distribution, densities and population structure of O. edulis in Strangford Lough. The approach adopted involved comparing predictive 2D hydrodynamic models coupled with particle tracking to simulate the dispersal of oyster larvae with historical and recent field records of the distribution of both subtidal and intertidal, populations since 1995. Results from the models support the hypothesis that commercial stocks of O. edulis introduced into Strangford Lough in the 1990s resulted in the re-establishment of wild populations of oysters in the Northern Basin which in turn provided a potential source of propagules for subtidal populations. These results highlight that strategic site selection (while inadvertent in the case of the introduced population in 1995) for the re-introduction of important shellfish species can significantly accelerate their recovery and restoration.

Willingness to pay for potential enhancements to a low-cost cataract surgical package in rural southern China.

PURPOSE: To assess determinants of patients' willingness to pay (WTP) for potential components of a multi-tiered cataract surgical package offered by a non-governmental organization (NGO) in rural China. DESIGN: Cross-sectional study. METHODS: Demographic and clinical data were collected from 505 patients presenting for cataract screening or surgery in Yangjiang, China. Willingness to pay for potential enhancements to the current surgery package was assessed using a bidding format with random payment cards. RESULTS: Among 426 subjects (84.4%) completing interviews, the mean age was 73.9 ± 7.3 years, 67.6% were women and 73% (n = 310) would pay for at least one offering, with 33-38% WTP for each item. Among those who would pay, the mean WTP for food was US$1.68 ± 0.13, transportation US$3.24 ± 0.25, senior surgeon US$50.0 ± 3.36 and US$89.4 ± 4.19 for an imported intra-ocular lens (IOL). The estimated total recovery from these enhancements under various assumptions would be US$20-50 (compared to the current programme price of US$65). In multivariate models, WTP for the senior surgeon increased with knowledge of a person previously operated for cataract (OR = 2.13, 95% CI 1.42-3.18, p < 0.001). Willingness to pay for the imported IOL increased with knowledge of a previously operated person (OR = 1.85, 95% CI 1.24-2.75, p < 0.01) and decreased with age >75 years (OR = 0.61, 0.40-0.93, p < 0.05). CONCLUSIONS: Opportunities exist to increase cataract programme revenues through multi-tiered offerings in this setting, allowing greater subsidization of low-income patients. Personal familiarity with cataract surgery is important in determining WTP. © 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.

Murine Models of Diastolic Dysfunction and Heart Failure With Preserved Ejection Fraction

Left ventricular diastolic dysfunction leads to heart failure with preserved ejection fraction, an increasingly prevalent condition largely driven by modern day lifestyle risk factors. As heart failure with preserved ejection fraction accounts for almost one-half of all patients with heart failure, appropriate nonhuman animal models are required to improve our understanding of the pathophysiology of this syndrome and to provide a platform for preclinical investigation of potential therapies. Hypertension, obesity, and diabetes are major risk factors for diastolic dysfunction and heart failure with preserved ejection fraction. This review focuses on murine models reflecting this disease continuum driven by the aforementioned common risk factors. We describe various models of diastolic dysfunction and highlight models of heart failure with preserved ejection fraction reported in the literature. Strengths and weaknesses of the different models are discussed to provide an aid to translational scientists when selecting an appropriate model. We also bring attention to the fact that heart failure with preserved ejection fraction is difficult to diagnose in animal models and that, therefore, there is a paucity of well described animal models of this increasingly important condition.