A choice experiment application to estimate willingness to pay for controlling excessive recreational fishing demand at the Sundays River Estuary, South Africa

The Sundays River Estuary, situated in the Eastern Cape, South Africa, has excessive recreational demand for estuarine services, specifically recreational fishing. The estuary has been over-fished, putting its sustainability at risk. Various management interventions may be required in order to save it, but how is this to be done without reducing welfare? The main aim of this paper is twofold: first, to assess and comprehend the economic value of the estuarine resources at stake; and, second, to propose policy measures to redress the situation (excessive demand, specifically recreational fishing). An application of a choice experiment reveals that the physical size of fish stocks is a very important predictor of recreational choice at the Sundays River Estuary, and it is recommended that demand be curtailed through an increase in the boat license fee for using the estuary of ZAR174 per annum.Keywords: Estuary, demand management, recreational attributes, recreational fishery, choice experimen

Application of the contingent valuation method to estimate a recreational value for the freshwater inflows into the Kowie and the Kromme Estuaries

This paper assesses the amount recreational users are willing to pay to secure an increase in freshwater inflows into 2 South African estuaries, the Kowie and the Kromme. A questionnaire was administered to 150 respondents at each estuary site during the period December 2002 to January 2003. The values of freshwater inflows into the Kowie and the Kromme Estuaries were calculated at R0.072/m3 and R0.013/m3, respectively. Total WTP values were estimated at R938 296.59 and R974 019.20, respectively. A valuation function to predict willingness-to-pay was predicted using the Tobit model estimation of linear bid functions. Annual levies paid (consisting of fishing licences, boat registration fees, etc.), distance of current accommodation to estuary, number of household members, primary use of estuary (i.e. recreation or commercial), how informed the respondent was and investment in boats and vehicles were shown to be important predictors of willingness-to-pay in the case of the Kromme Estuary. Level of education, race of respondent, annual levies paid, investment in estuary access equipment and respondent status (i.e., visitor vs. non-visitor) were shown to be important predictors of willingness-to-pay in the case of the Kowie Estuary. An expectations validity assessment indicated that the estimates were credible

Improving navigability on the Kromme River Estuary: A choice experiment application

Navigation of estuaries is a vitally important aspect of boating recreation in South Africa and elsewhere. This paper uses a choice experiment to estimate recreation values of the Kromme River Estuary, a popular estuary along South Africa’s east coast. This valuation methodology allows for the identification of preferred management strategies through the trade-offs made by estuarine recreational users. It is found that the level of navigability is the most important predictor of user choice, and argued that more attention needs to be paid to options for improving navigability and methods to fund these interventions. It is concluded that an increase in licence fee of ZAR402 would improve recreational value.Keywords: estuary, recreational attributes, navigability, choice experiment, willingness-to-pay, conditional logit model, random parameters logit mode

Comparative Linkage Meta-Analysis Reveals Regionally-Distinct, Disparate Genetic Architectures: Application to Bipolar Disorder and Schizophrenia

New high-throughput, population-based methods and next-generation sequencing capabilities hold great promise in the quest for common and rare variant discovery and in the search for ”missing heritability.” However, the optimal analytic strategies for approaching such data are still actively debated, representing the latest rate-limiting step in genetic progress. Since it is likely a majority of common variants of modest effect have been identified through the application of tagSNP-based microarray platforms (i.e., GWAS), alternative approaches robust to detection of low-frequency (1–5% MAF) and rare (<1%) variants are of great importance. Of direct relevance, we have available an accumulated wealth of linkage data collected through traditional genetic methods over several decades, the full value of which has not been exhausted. To that end, we compare results from two different linkage meta-analysis methods—GSMA and MSP—applied to the same set of 13 bipolar disorder and 16 schizophrenia GWLS datasets. Interestingly, we find that the two methods implicate distinct, largely non-overlapping, genomic regions. Furthermore, based on the statistical methods themselves and our contextualization of these results within the larger genetic literatures, our findings suggest, for each disorder, distinct genetic architectures may reside within disparate genomic regions. Thus, comparative linkage meta-analysis (CLMA) may be used to optimize low-frequency and rare variant discovery in the modern genomic era

Factores que determinan la acción de chatear por celular mientras se camina

1 recurso en línea (97 páginas) : ilustraciones, figuras, tablas.El presente trabajo de investigación estudia los factores que determinan la acción de chatear mientras se camina, con el propósito de analizar sus causas, desde la perspectiva de los usuarios, y plantear medidas que ayuden a mitigar la conducta de chatear mientras se camina de los peatones. La metodología usada tuvo dos perspectivas basadas en la aplicación de una encuesta a una muestra representativa de la población. En primer lugar, se hizo un análisis empírico a partir de la obtención de barras apiladas divergentes, para un conjunto de indicadores de variables latentes, basados en indicadores de tipo Likert. En segundo lugar, tomando los datos de un experimento de preferencias declaradas, mediante un proceso iterativo, se hizo la estimación de modelos de tipo Logit multinomial a través del software de uso libre Biogeme. De esta manera se pudo concluir que los factores determinantes de la conducta de chatear mientras se caminan están relacionados con características sociales del individuo, políticas de tránsito, características de la infraestructura urbana, características socio-económicas de las personas, así como las características propias del uso del teléfono de cada individuo.Bibliografía y webgrafía: páginas 94-97.PregradoIngeniero de Transport

Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer.

To identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC

Socio-economic aspects of the tiger shark diving industry within the Aliwal Shoal Marine Protected Area, South Africa

Understanding socio-economic aspects of the tiger shark Galeocerdo  cuvier diving industry, including information on participant expectations, experiences and expenditure, is necessary for the effective management of the Aliwal Shoal Marine Protected Area on  the east coast of South Africa. Between January and December 2007, a total of 2 133 tiger shark dives was conducted by 1 065 divers (95% CI = 946–1 198). Data were collected by means of the administration of a semi-structured survey questionnaire to 197 (18.6%) dive participants. Respondents indicated that the direct value of tiger shark diving to the Aliwal Shoal region was R12 405 274 (95% CI = R10 777 324–14 228 541). A total of 1 000 Monte Carlo simulations was used to estimate confidence intervals. On a ranking from one (poor) to five (excellent), the average participant response to overall quality of dive and standard of dive operator was 4.6 and 4.7 respectively. The majority of divers (98.0%) observed a tiger shark, at an average of four per dive. Although tiger sharks approached to an average distance  of 1.6 m from divers, the majority (95.9%) felt safe and enjoyed the  experience. The majority of interviewees (88.5%) supported the use of chumming for a closer ‘tiger shark experience’. Keywords: Aliwal Shoal; marine protected area; socio-economic; South Africa; tiger sharkAfrican Journal of Marine Science 2009, 31(2): 227–23