Mitigation and Adaptation Practices to the Impact of Climate Change on Wine Grape Production, with Special Reference to the South African Context

In South Africa, environmentally and socio-economically sustainable wine grape production is promotedby governmental and private initiatives. All the initiatives contribute to establishing a scientificallybased response strategy of agro-systems to ensure sustainable production under future expected climateconditions. South African wine grape producers would probably have to cultivate their grapevines underhigher atmospheric CO2 levels and in warmer, mostly drier, conditions. Due to the projected increase inclimatic variability, an effort must be made to improve the resilience of vines against these environmentalconditions. Whole-vine functioning and balances should be considered when adjustments are madeto current long and short term cultivation practices. All practices should be aimed at promoting thedevelopment of a deep, dense and buffered root system that is able to support a well-developed canopywith optimal microclimate that would sustain a high yield of good quality. Mitigation and adaptationstrategies would most likely have to be region specific, and small scale terroir data, (which should includeboth climate and terrain/soil information) may play a critical role in decision-making

Validation of the high performance leadership competencies as measured by an assessment centre in-basket

The original publication is available at http://www.sajip.co.zaCITATION: Spangenberg, H. H. & Theron, C. C. 2003. Validation of the high performance leadership competencies as measured by an assessment centre in-basket. SA Journal of Industrial Psychology, 29(2):29-38, doi:10.4102/sajip.v29i2.106.The purpose of this study was to validate Schroder’s High Performance Leadership Competencies (HPLCs), measured by a specially designed In-basket, against multiple criteria. These consisted of six measures of managerial success, representing managerial advancement and salary progress criteria, and a newly developed comprehensive measure of work unit performance, the Performance Index. An environmental dynamism and complexity questionnaire served as moderator variable. Results indicated disappointing predictive validity quotients for the HPLCs as measured by an In-basket, in contrast to satisfactory predictive and construct validity obtained in previous studies by means of a full assessment centre. The implications of the findings are discussed and suggestions are made for improving the validity of the In-basket.Die doel van hierdie studie was die validering van Schroder se Hoëvlak Leierskapsbevoegdhede, gemeet deur ‘n spesiaal ontwerpte Posmandjie, teen veelvoudige kriteria. Dit behels ses metings van bestuursukses wat bestuursbevorderings- en salarisvorderingskriteria insluit, sowel as ‘n nuutontwikkelde, omvattende meting van werkeenheidsprestasie, die Prestasie indeks. ‘n Vraelys wat die dinamika en kompleksiteit van die omgewing meet, het as moderator veranderlike gedien. Resultate dui op teleurstellende geldigheidskwosiënte vir die Hoëvlak Leierskapsbevoegdhede soos gemeet deur ‘n posmandjie, in teenstelling met bevredigende voorspellings- en konstrukgeldigheid wat in vorige studies deur middel van ‘n volle takseersentrum verkry is. Die bevindinge word bespreek en voorstelle word gemaak om die geldigheidskwosiënte te verbeter.https://sajip.co.za/index.php/sajip/article/view/106Publisher's versio

Effect of Irrigation with Diluted Winery Wastewater on the Performance of Two Grass Cover Crops in Vineyards

Pennisetum glaucum L. cv. Babala (pearl millet) established as a summer catch crop followed by Avena sativa L. cv Palinup (oats) established as a winter catch crop were irrigated with winery wastewater diluted to eight chemical oxygen demand (COD) levels ranging between 100 mg/L and 3 000 mg/L. The diluted wastewater treatments were compared to irrigation with river water. The dry matter production (DMP) of oats, if not preceded by pearl millet, tended to improve when irrigated with winery wastewater. Growth of pearl millet peaked during the period when 91% of the diluted winery wastewater was applied. Winery wastewater improved the DMP of pearl millet. No trends were observed in the nutrient levels of the above-ground growth of the two interception crops. However, Na levels increased over time. Using both species, too high levels of macro-nutrients were intercepted, but insignificant amounts of Na were removed. Irrigation with winery wastewater with COD levels between 1 500 mg/L and 2 500 mg/L may be sustainable if only pearl millet is employed as an interception crop. Fertiliser needed to maintain the nutrient balance in the soil resulted in an additional cost of approximately R2 800/ha/yr. However, the fodder may provide an income in excess of R15 000/ha/yr

Additional Evidence Against Radio-handicapping of Northern Bobwhites

The validity of radio-telemetry to produce reliable information (e.g., survival estimates) has recently been challenged. Radio-telemetry is a widely used technique in studies of numerous species, therefore, concerns regarding potential bias in these estimates warrant further investigation. As such, and as part of a larger study, we investigated 3 aspects of potential radio-bias: 1) variation in survival distributions among treatment (newly radio-tagged) and control (previously radio-tagged) groups; 2) proportion of trapped animals censored during the traditional 7-day censor period; and 3) ramifications to cause-specific mortality through estimation of harvest rate. Kaplan-Meier survival, based on 30-day post trapping, was similar between treatment (n = 901) and control (n = 293) bobwhites for all but 1 of 8 trapping sessions during 2000-2004. In this case, treatment bobwhites (0.970, SE = 0.015) had higher survival than control birds (0.878, SE = 0.042). We determined the effect of censoring relative to sample size was inconsequential for our analysis because the proportion of bobwhites (18 out of 1,350; 0.013) meeting the criteria for censoring, i.e., dying during the first 7 days, was minimal. Censoring of these data influenced survival estimates by an average of only 0.016 (SE = 0.004; range: 0.00 - 0.04). We evaluated harvest rate by comparing first year recovery rates of banded verses radio-tagged birds during thirteen hunting seasons occurring between 1992 and 2005. Annual recovery rate was not different (P \u3c 0.05) for banded birds and radio-tagged birds where harvest averaged 6.68% (range 3.3 - 11.7) and 6.65% (range 3.4 - 11.1), respectively. These findings are consistent with previous research demonstrating that radio-telemetry can provide reliable demographic information. However, we recommend that future researchers test for these potential effects among their data before making biological inferences

Transgender in Africa: Invisible, inaccessible, or ignored?

Transgender people are an important key population for HIV risk globally, and several studies have found HIV prevalence rates in transgender populations that are significantly higher than those among other key populations such as men who have sex with men (MSM). There is a lack of research on transgender populations in Africa, and at present, there is almost no data available on HIV prevalence and risk among transgender people on the continent. It is possible that the invisibility of transgender people in epidemiological data from Africa is related to the criminalisation of same-sex behaviour in many countries and the subsequent fear of negative repercussions from participation in research. Alternatively, transgender people may be being overlooked in research due to confusion among researchers about how to ask questions about gender identity. It is also possible that transgender populations have simply been ignored in research to date. Without research on transgender-specific HIV prevalenceand risk, it is very difficult to know what interventions and services are needed for this risk population. Therefore, it is important that researchers, governments, Non Governmental Organisations (NGOs) and donor organisations begin to pay explicit attention to transgender people in their HIV-related research and programmes in Africa

Bosonization in d=2 from finite chiral determinants with a Gauss decomposition

We show how to bosonize two-dimensional non-abelian models using finite chiral determinants calculated from a Gauss decomposition. The calculation is quite straightforward and hardly more involved than for the abelian case. In particular, the counterterm $A\bar A$, which is normally motivated from gauge invariance and then added by hand, appears naturally in this approach.Comment: 4 pages, Revte

Die geografiese invloede op die wynboubedryf in die Suid-westelike distrikte van die Kaapprovinsie

Thesis (MScAgric)--Stellenbosch University, 1932.No Abstract Availabl

Development of a questionnaire for assessing work unit performance

The original publication is available at http://www.sajip.co.zaThe aim of this study was to develop a generic work unit performance measure that can be utilized in private, public and non-profit work units. Development of such a questionnaire, called the Performance Index (PI) comprised three steps, namely deciding on a baseline structure for the model; verifying the model and dimensions through subject expert feedback; and consolidating the model and refining the questionnaire. The sample consisted of 60 units rated on a 360 basis by 257 respondents. Item and dimensionality analyses, followed by confirmatory factor analysis utilizing LISREL produced acceptable model fit. Overall, results provided reasonable psychometric support for the Performance Index.Die doel van die studie was om ’n generiese werkeenheid- prestasiemeting te ontwikkel wat in privaat, openbare en nie-winsgerigte organisasies gebruik kan word. Die ontwikkeling van die vraelys, die Prestasie-Indeks (PI) het drie stappe behels, naamlik om te besluit op ’n onderliggende struktuur vir die model; om die model en dimensies deur middel van ekspert-beoordeling te verifieer; en om die model te konsolideer en die vraelys af te rond. Die steekproef het bestaan uit 60 eenhede wat op ’n 360-basis deur 257 respondente beoordeel is. Item- en dimensionaliteitsontledings, gevolg deur Lisrel-gedrewe bevestigende faktorontleding het gedui op aanvaarbare modelpassing. In geheel beslou het resultate redelike psigometriese ondersteuning aan die Prestasie-Indeks verleen.Publisher's versio

Northern Bobwhite Demographic and Population Response Following an Intensive Habitat Modification to an Agricultural Landscape

Northern Bobwhite (Colinus virginianus) populations have been declining throughout most of their endemic range due to numerous factors (e.g., increased urbanization, predators); however, changing land-use practices have proved most detrimental to bobwhites. In parts of the southeastern USA, small-scale farming has been replaced by large-scale center-pivot irrigated fields and this has exacerbated habitat loss. Despite these trends, bobwhite populations in the Southeast have remained stable or increased on many areas employing intensive habitat management regimes, substantiating the importance of appropriate habitat management for long-term bobwhite persistence. In effort to reverse one such decline, we intensively modified a center-pivot, agriculture dominated landscape to benefit bobwhites by creating new habitat and improving existing habitat. Techniques utilized to modify this landscape were: establishment of linear habitats (field borders and buffer strips); planting longleaf pines; and management of existing habitat via prescribed burning and timber management. During 1998-2001, we monitored bobwhite (n = 498) demographics and population response following annual habitat restoration and management using radio-telemetry and fall abundance estimation (i.e., covey call-counts). Average survival during over-winter (0.4698, SE = 0.0721), breeding (0.3561, SE = 0 .0667) and annual (0.1673, SE = 0.0411) time-periods were higher than those reported for other agriculture studies and similar to those of intensively managed, “plantation” habitats. Bobwhite coveys and broods used newly developed longleaf pine, linear habitats (e.g. field borders/hedgerows), and managed woodlands. Further, nest site selection was commonly associated with these novel habitat types. As a result of the positive demographic response to habitat modification, bobwhite abundance also improved during the study. Consequently, we surmised that modification of agricultural landscapes may improve habitat quality and quantity for bobwhites and subsequently help to increase demographic rates and bobwhite abundance

Summer Male Call Index Relative to Nesting Chronology and Autumn Density of the Northern Bobwhite

We studied breeding season male call counts and breeding behavior of the Northern Bobwhite (Colinus virginianus) to determine the relationship between male calling activity and nesting chronology. Additionally, we examined the relationship between breeding season call counts and fall population size. Standardized call count routes were conducted on 6 different sites located in southwest Georgia and north Florida during the breeding season months (1 Apr - 31 Sep) in 2001 and 2002. An information theoretic approach was used to evaluate a set of 7 candidate, linear-mixed models describing breeding season calling of bobwhite males. Of the candidate models, the model in which call counts depended on year and a quadratic effect of the number of incubating hens was the best approximating model, suggesting that the percentage of incubating hens had the greatest influence on activity of calling males. We also used multiple linear regression models to predict autumn northern bobwhite abundance from mean numbers of calling male bobwhites detected during the breeding season. Peaks in male calling activity occurring during June and July demonstrated a strong relationship (R2 = 0.987) with autumn population size, suggesting breeding season call counts were useful indices of autumn bobwhite abundance