Social-ecological network analysis for sustainability sciences: a systematic review and innovative research agenda for the future.

Social-ecological network (SEN) concepts and tools are increasingly used in human-environment and sustainability sciences. We take stock of this budding research area to further show the strength of SEN analysis for complex human-environment settings, identify future synergies between SEN and wider human-environment research, and provide guidance about when to use different kinds of SEN approaches and models. We characterize SEN research along a spectrum specifying the degree of explicit network representation of system components and dynamics. We then systematically review one end of this spectrum, what we term "fully articulated SEN" studies, which specifically model unique social and ecological units and relationships. Results show more focus on methodological advancement and applied ends. While there has been some development and testing of theories, this remains an area for future work and would help develop SENs as a unique field of research, not just a method. Authors have studied diverse systems, while mainly focused on the problem of social-ecological fit alongside a scattering of other topics. There is strong potential, however, to engage other issues central to human-environment studies. Analyzing the simultaneous effects of multiple social, environmental, and coupled processes, change over time, and linking network structures to outcomes are also areas for future advancement. This review provides a comprehensive assessment of (fully articulated) SEN research, a necessary step that can help scholars develop comparable cases and fill research gaps.

Improving network approaches to the study of complex social-ecological interdependencies.

Achieving effective, sustainable environmental governance requires a better understanding of the causes and consequences of the complex patterns of interdependencies connecting people and ecosystems within and across scales. Network approaches for conceptualizing and analyzing these interdependencies offer one promising solution. Here, we present two advances we argue are needed to further this area of research: (i) a typology of causal assumptions explicating the causal aims of any given network-centric study of social-ecological interdependencies; (ii) unifying research design considerations that facilitate conceptualizing exactly what is interdependent, through what types of relationships, and in relation to what kinds of environmental problems. The latter builds on the appreciation that many environmental problems draw from a set of core challenges that re-occur across contexts. We demonstrate how these advances combine into a comparative heuristic that facilitates leveraging case-specific findings of social-ecological interdependencies to generalizable, yet context-sensitive, theories based on explicit assumptions of causal relationships.

Acceptability of pre-exposure prophylaxis as an HIV prevention strategy: barriers and facilitators to pre-exposure prophylaxis uptake among at-risk Peruvian populations.

This study examined pre-exposure prophylaxis (PrEP) acceptability among female sex workers, male-to-female transgendered persons and men who have sex with men in Lima, Peru. Focus groups explored social issues associated with PrEP acceptability and conjoint analysis assessed preferences among eight hypothetical PrEP scenarios with varying attribute profiles and their relative impact on acceptability. Conjoint analysis revealed that PrEP acceptability ranged from 19.8 to 82.5 out of a possible score of 100 across the eight hypothetical PrEP scenarios. Out-of-pocket cost had the greatest impact on PrEP acceptability (25.2, P < 0.001), followed by efficacy (21.4, P < 0.001) and potential side-effects (14.7, P < 0.001). Focus group data supported these findings, and also revealed that potential sexual risk disinhibition, stigma and discrimination associated with PrEP use, and mistrust of health-care professionals were also concerns. These issues will require careful attention when planning for PrEP roll-out.

Treatment of lysosomal storage disease in MPS VII mice using a recombinant adeno-associated virus.

Mucopolysaccharidosis type VII (MPS VII) is a lysosomal storage disease caused by a genetic deficiency of beta-glucuronidase (GUS). We used a recombinant adeno-associated virus vector (AAV-GUS) to deliver GUS cDNA to MPS VII mice. The route of vector administration had a dramatic effect on the extent and distribution of GUS activity. Intramuscular injection of AAV-GUS resulted in high, localized production of GUS, while intravenous administration produced low GUS activity in several tissues. This latter treatment of MPS VII mice reduced glycosaminoglycan levels in the liver to normal and reduced storage granules dramatically. We show that a single administration of AAV-GUS can provide sustained expression of GUS in a variety of cell types and is sufficient to reverse the disease phenotype at least in the liver.

Perioperative complications of long-term central venous catheters in high-risk patients: predictors versus myths.

A prospective cohort of 126 patients having long-term central venous catheterization was collected over a 10-month period. The patients were preoperatively assessed for the following risk factors: previous catheter placement, an absolute neutrophil count less than 500/mm3, a platelet count less than 50,000/mm3, a BUN value greater than 60 mg/dL or a serum creatinine level greater than 2.5 mg/dL, a prothrombin time greater than 1.5 times control, recent sepsis, and a Western blot test positive for HIV. The incidence of perioperative complications was 23%. Complications included pneumothorax, arterial puncture, tunnel hematoma, unsuccessful initial placement, and reaction to local anesthesia or blood products. No single risk factor had any statistical significance in predicting a complication. In the subpopulation of patients having two or more risk factors, the complication rate was 50%, with the majority of these being failed placement attempts. We conclude that inserting a permanent central venous catheter is not a benign procedure, but it can be safely done in critically ill patients. Furthermore, evaluation of preoperative risk factors in candidates for catheterization can be helpful to the surgeon with respect to counseling and operative planning.

Lack of metabolic effects of cholecystokinin on hepatocytes.

We previously reported that the liver was the major organ that extracts small, biologically active, circulating forms of cholecystokinin. Although our work indicated extensive degradation of cholecystokinin extracted from plasma during its transit across the hepatocyte, it was unclear whether cholecystokinin might also have a physiological effect on this cell before its intracellular degradation. Therefore we tested the hypothesis that cholecystokinin has a direct biological effect on hepatocytes. Using freshly isolated or cultured hepatocytes, we studied whether cholecystokinin-octapeptide alters protein synthesis, affects amino acid transport or influences cytosolic free calcium concentrations. Using liver slices, we also determined the effect of cholecystokinin-octapeptide on cyclic nucleotide levels. Cholecystokinin-octapeptide, up to a concentration of 1 mumol/L, had no effect on the incorporation of radiolabeled amino acids into total hepatocyte protein; in contrast, comparable molar amounts of insulin stimulated protein synthesis by as much as 37% (ED50 = 1.5 x 10(-10) mol/L). Although insulin and glucagon stimulated the transport into hepatocytes of 14C-alpha-aminoisobutyric acid, a nonmetabolizable amino acid analog, cholecystokinin-octapeptide had no affect Cholecystokinin-octapeptide also did not affect either the concentration of calcium in individual hepatocytes, as measured by digitized video microscopy using Fura-2, or the levels of cyclic AMP or cyclic GMP in liver slices. Our results show that cholecystokinin has no effect on protein synthesis, on amino acid transport or on hepatocyte calcium and cyclic nucleotide levels. These and our previous data suggest that the primary outcome of hepatic extraction of cholecystokinin is hormone degradation.

Self-esteem, social support, and positive health practices.

The purpose of this study was to identify relationships among perceived social support, self-esteem, and positive health practices among adults living in a south-western metropolitan area. The sample (N = 98) of convenience was selected from an adult apartment complex and the variables were measured using three self-report questionnaires (Personal Resource Questionnaire, Coopersmith Self-Esteem Inventory, and Personal Life-style Activities Questionnaire). Initially, a positive association among the variables, self-esteem, social support, and life-style, was determined using a simple correlation matrix. To further explicate the relationships among the variables, a theoretical causal model was developed and tested. Using path analytic techniques, both the direct and the indirect effects of various independent variables on life-style were determined; 28% of the variance, p less than .0001, was accounted for by this model. The study suggests that both self-esteem and social support are positive indicators of life-style. Further, social support was found to exert influence indirectly through its direct effect on self-esteem.