Biogeography of ocean acidification: Differential field performance of transplanted mussels to upwelling-driven variation in carbonate chemistry.

Ocean acidification (OA) represents a serious challenge to marine ecosystems. Laboratory studies addressing OA indicate broadly negative effects for marine organisms, particularly those relying on calcification processes. Growing evidence also suggests OA combined with other environmental stressors may be even more deleterious. Scaling these laboratory studies to ecological performance in the field, where environmental heterogeneity may mediate responses, is a critical next step toward understanding OA impacts on natural communities. We leveraged an upwelling-driven pH mosaic along the California Current System to deconstruct the relative influences of pH, ocean temperature, and food availability on seasonal growth, condition and shell thickness of the ecologically dominant intertidal mussel Mytilus californianus. In 2011 and 2012, ecological performance of adult mussels from local and commonly sourced populations was measured at 8 rocky intertidal sites between central Oregon and southern California. Sites coincided with a large-scale network of intertidal pH sensors, allowing comparisons among pH and other environmental stressors. Adult California mussel growth and size varied latitudinally among sites and inter-annually, and mean shell thickness index and shell weight growth were reduced with low pH. Surprisingly, shell length growth and the ratio of tissue to shell weight were enhanced, not diminished as expected, by low pH. In contrast, and as expected, shell weight growth and shell thickness were both diminished by low pH, consistent with the idea that OA exposure can compromise shell-dependent defenses against predators or wave forces. We also found that adult mussel shell weight growth and relative tissue mass were negatively associated with increased pH variability. Including local pH conditions with previously documented influences of ocean temperature, food availability, aerial exposure, and origin site enhanced the explanatory power of models describing observed performance differences. Responses of local mussel populations differed from those of a common source population suggesting mussel performance partially depended on genetic or persistent phenotypic differences. In light of prior research showing deleterious effects of low pH on larval mussels, our results suggest a life history transition leading to greater resilience in at least some performance metrics to ocean acidification by adult California mussels. Our data also demonstrate "hot" (more extreme) and "cold" (less extreme) spots in both mussel responses and environmental conditions, a pattern that may enable mitigation approaches in response to future changes in climate.

Interacting environmental mosaics drive geographic variation in mussel performance and predation vulnerability.

Although theory suggests geographic variation in species' performance is determined by multiple niche parameters, little consideration has been given to the spatial structure of interacting stressors that may shape local and regional vulnerability to global change. Here, we use spatially explicit mosaics of carbonate chemistry, food availability and temperature spanning 1280 km of coastline to test whether persistent, overlapping environmental mosaics mediate the growth and predation vulnerability of a critical foundation species, the mussel Mytilus californianus. We find growth was highest and predation vulnerability was lowest in dynamic environments with frequent exposure to low pH seawater and consistent food. In contrast, growth was lowest and predation vulnerability highest when exposure to low pH seawater was decoupled from high food availability, or in exceptionally warm locations. These results illustrate how interactions among multiple drivers can cause unexpected, yet persistent geographic mosaics of species performance, interactions and vulnerability to environmental change.

Morbidity Profiles of People Living With HIV/AIDS in Urban and Rural Inpatient and Outpatient Settings in Karnataka, South India.

We examined the morbidity profiles associated with people living with HIV infection in an urban HIV inpatient treatment site near the city of Bangalore, in southern Karnataka state, south India, and in a rural outpatient site in northern Karnataka. Data from March 2007 until July 2008 were analyzed. The urban cohort comprised 432 patients, and the most common comorbid conditions were unexplained prolonged fever (50.2%) and oral candidiasis (42.6%). The rural cohort comprised 2374 patients, and the most common comorbid conditions were unexplained prolonged fever (58.8%), minor mucocutaneous infections (58.4%), and recurrent upper respiratory tract infections (52.3%). With less than 1% of patients in rural areas on treatment for tuberculosis (vs over one third in the urban cohort), tuberculosis is likely significantly underdiagnosed in rural areas. In addition, only 2.6% of rural outpatients who were eligible for antiretroviral treatment (ART), per Government of India guidelines, were actually on ART, compared to 31.6% of the urban population.

Continuum of care model for managing mild traumatic brain injury in a workers' compensation context: a description of the model and its development.

Mild traumatic brain injuries are a significant health problem that can result in distress and disability for people who go on to develop post-concussion syndrome or symptoms. In order to improve healthcare outcomes following a mild traumatic brain injury, the Workers' Compensation Board of Alberta developed a continuum of care model to assist its staff (e.g. claim adjudication and case management) to manage these claims. A continuum of care model acts as a road map that illustrates typical recovery patterns and treatment best practices, and builds in checkpoints where decisions for assessment and treatment can be made. The model was developed from a review of the research literature selected to determine the best evidence-based practices for treating mild traumatic brain injury, and the most appropriate timing for assessments and treatments. Local and international experts in the field of brain injury assessment and rehabilitation also contributed to the development of the final model.