Autonomous light-weight heliostat with rim drives

Several approaches for cost reduction of heliostats, which fit well to each other, are combined to a new heliostat concept to achieve the current challenging cost objectives: The wind loads are reduced by appropriate manipulators which reduces weight and cost of the heliostat structure and the ground anchor foundation. Laminated mirror facets are of high reflectivity and shape accuracy and of low weight. The low weight is advantageous for the dimensioning of the bearings and regarding energy consumption. Energy consumption is further reduced by a highly efficient drive train. Thus, small capacity of the wireless energy supply of the autonomous heliostat is sufficient which reduces significantly its cost. By the combination of horizontal primary axis with rims and winch wheels a cheap and precise solution for the drives was found. Ray tracing calculations show that the losses due to the compromised angle range are negligible. With the new heliostat concept the current cost goals seem to be achievable

Cricket: Nature and incidence of fast-bowling injuries at an elite, junior level and associated risk factors

Objective. To compile an injury profile of 46 fast bowlers aged 11 - 18 years, and to identify the associated risk factors for injury during one academy cricket season. Methods. The fast bowlers selected were tested and observed for one academy cricket season (March - November). Subjects were grouped into injury classifications (uninjured=S1; injured but able to play=S2; injured and unable to play=S3). Anthropometrical and postural data for the subjects were collected preseason (T1). Physical fitness screenings were conducted and the relationship between fitness and occurrence of injuries was assessed. Additional factors such as bowling techniques and bowling workload were assessed. A regression analysis was conducted to analyse the relationship between bowling workload and weeks incapacitated. Results. Fifteen per cent of the subjects remained injury free for the duration of the season. The incidence of serious injury (S3) showed a statistical and moderate, practical significant increase (V=0.23, df≥2) throughout the data collection period (4% at T1 - 30% at T3 (post-season)). The most common injuries were to the knee (41%) and lower back (37%), occurring from mid-season (T2) to T3. The nature of the injuries was predominantly strains (39%) and ‘other' (39%), with the highest reported incidence during the period T1 - T3. Sprains followed, with an overall incidence of 14%. Subjects were incapacitated approximately 1 out of every 7 weeks of play. The S1 and S2 bowlers performed consistently better than the S3 bowlers in all the fitness variables tested. Bowling workload presented a statistically significant (

Clinicopathological Conference: Abnormal Sex Characteristics and Intracranial Mass

Clinicopathlogical conference transcript from the Medical College of Virginia. Discussants include Clark T. Randt, Gerald A. Gildersleeve, and Julio H. Garcia

Expectations and experiences of talent management across South Africa and the effect on retention

The “war on talent” is intensifying and effective talent management strategies are imperative for business success. This study explores the expectations and experiences of talent management strategies amongst employees across South Africa and their impact on retention. The literature review covers the constructs of talent management, working environment, rewards, leadership, race, age and gender as well as retention. A quantitative survey approach with comparative studies was adopted. A snowball convenience sampling method was used with links to an on-line questionnaire e-mailed to potential respondents. A total of 711 useable responses were received. Statistical analysis included factor analysis, Cronbach alpha reliability testing, mean factor scores, paired samplet-tests, Pearson’s correlations, T-tests and ANOVAs. The study found that leadership was the factor rated as most important followed by working environment and development. Respondents reported significant differences between expectations and employer ratings on all factors, with cash rewards being the greatest source of dissatisfaction. Experiences of work environment, leadership and development indicated stronger correlations to retention than cash rewards. Women, millennials and non-whites demonstrated the highest retention risks. A significant negative correlation was found between the respondents’ reported experience of leadership, work environment and development and the importance they attached to cash rewards. The study supports Hertzberg’s classification of cash rewards as a hygiene factor and Alderfer’s ERG theory’s concept of frustration-regression. This has significant implications for the focus of talent and retention strategies, and it is proposed that improving the quality of leadership, work environments and development opportunities will decrease the current over-reliance on monetary rewards as a retention tool

Corrigendum

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The physical activity and health status of two generations of Black South African professional women

Increased health risks associated with physical inactivity in the Black population have been reported in recent years. Black women, suffering the highest levels of inactivity, overweight and obesity, are at greatest risk of developing chronic diseases of lifestyle. This explorativedescriptive study investigated the physical activity patterns and health status of two generations of Black professional women, reflecting pre-democracy and post-democracy age groups. Quantitative measures were used, including the ActiGraph GT1M accelerometer, the Global Physical Activity Questionnaire and the Health-Promoting Lifestyle Profile. Sample groups comprised teachers, nurses, social workers and public sector managers. Participants aged between 35 and 45 years were allocated to the older generation group (n = 111), whilst those aged between 18 and 21 years (students in the mentioned professional fields) were allocated to the younger generation group (n = 69). The results indicated that these women displayed lower levels of health-promoting behavioural practices than expected, significantly lower levels of physical activity and significantly higher levels of overweight and obesity than the South African norms. The observation that the younger group appeared to be replicating the patterns of the older women is a cause of concern. Greater compliance to health-promoting behaviours was expected in this group owing to participants’ professional involvement in health, education and social development fields. Wide-ranging initiatives are necessary to promote physical activity and health amongst the Black female population in South Africa. Opsomming Gedurende die afgelope jare het navorsing onder die Swart bevolking ʼn toename in gesondheidsrisiko’s wat met fisieke onaktiwiteit geassosieer is, getoon. Swart vroue, wat die hoogste vlakke van onaktiwiteit, oorgewig en obesiteit toon, blyk ook die grootste risiko te loop om leefstylverwante chroniese siektes te ontwikkel. Hierdie ondersoekendbeskrywende studie het die fisieke aktiwiteitspatrone en gesondheidstatus van twee generasies van Swart professionele vroue ondersoek. Die tweegenerasiesteekproef verteenwoordig voor- en na-demokrasie-ouderdomsgroepe. Kwantitatiewe meetinstrumente, naamlik die ActiGraph GT1M versnellingsmeter, Globale Fisieke Aktiwiteitsvraelys en die Gesondheidsbevorderende Leefstylprofiel is gebruik. Die steekproef het onderwysers, verpleegkundiges, maatskaplike werkers en bestuurders in die openbare sektor ingesluit. Deelnemers tussen 35 en 45 jaar is aan die ouergenerasie-toetsgroep toegewys (n = 111), terwyl dié tussen 18 en 21 jaar (studente in bogenoemde studierigtings) aan die jongergenerasietoetsgroep toegewys is (n = 69). Die resultate het gewys dat die Swart professionele vroue laer as verwagte gesondheidsbevorderende gedrag, betekenisvol laer vlakke van fisieke aktiwiteit en betekenisvol hoër vlakke van oorgewig en obesiteit toon as die Suid-Afrikaanse norme. Die waarneming dat die jonger groep dieselfde gedragspatrone as die ouer vroue getoon het, is ʼn bron van kommer. ʼn Groter nakoming van gesondheidsbevorderende gedrag is onder die jonger groep vroue verwag, aangesien hulle hul opleiding in die professionele sektor van gesondheid, onderwys en maatskaplike werk ontvang. ʼn Holistiese benadering is nodig om fisieke aktiwiteit en gesondheid onder Swart Suid-Afrikaanse vrouens te bevorder

Cricket: Nature and incidence of fast-bowling injuries at an elite, junior level and associated risk factors

Objective. To compile an injury profile of 46 fast bowlers aged 11 - 18 years, and to identify the associated risk factors for injury during one academy cricket season. Methods. The fast bowlers selected were tested and observed for one academy cricket season (March - November). Subjects were grouped into injury classifications (uninjured=S1; injured but able to play=S2; injured and unable to play=S3). Anthropometrical and postural data for the subjects were collected preseason (T1). Physical fitness screenings were conducted and the relationship between fitness and occurrence of injuries was assessed. Additional factors such as bowling techniques and bowling workload were assessed. A regression analysis was conducted to analyse the relationship between bowling workload and weeks incapacitated. Results. Fifteen per cent of the subjects remained injury free for the duration of the season. The incidence of serious injury (S3) showed a statistical and moderate, practical significant increase (V=0.23, df≥2) throughout the data collection period (4% at T1 - 30% at T3 (post-season)). The most common injuries were to the knee (41%) and lower back (37%), occurring from mid-season (T2) to T3. The nature of the injuries was predominantly strains (39%) and ‘other' (39%), with the highest reported incidence during the period T1 - T3. Sprains followed, with an overall incidence of 14%. Subjects were incapacitated approximately 1 out of every 7 weeks of play. The S1 and S2 bowlers performed consistently better than the S3 bowlers in all the fitness variables tested. Bowling workload presented a statistically significant (