Analysis of computer operator responses to personalised adjustments made to standard computer workstations : research article
- James, Genevieve, Scott, Patricia A
- Authors: James, Genevieve , Scott, Patricia A
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6743 , http://hdl.handle.net/10962/d1008391
- Description: Computer operators are often required to maintain static working postures at computer workstations which have been assembled in order to accommodate the morphologies of a maximum number of operators, and these workstations generally have a limited degree of adjustability. The present study sought to investigate the effects of a Standard workstation, designed for "average" users, on an anthropometrically diverse sample of computer operators, and to assess whether physical and perceptual responses, as well as performance efficiency were dependent on stature. Further investigation assessed the influence of personalised adjustments to the Standard workstation, based on the anthropometric characteristics of the subjects, as well as the introduction of a custom-designed 'floating' wrist support, on subject responses. All subjects (n=30) were tested in each of the three workstations: Standard, Personalised and Wrist Support. The responses elicited in the Personalised and Wrist Support workstations were improved significantly when compared to the Standard workstation. Joint angles were more natural, upper trapezius EMG was reduced, standard of performance improved and perceptual responses indicated a diminished incidence of body and visual discomfort, as well as greater perceived satisfaction with these workstation dimensions. Based on the findings of this study, it is recommended that sufficient adjustability be built into workstations so that it is possible to optimally personalise them for individual operators, thereby reducing the awkward postures adopted during this static type of work.
- Full Text:
- Authors: James, Genevieve , Scott, Patricia A
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6743 , http://hdl.handle.net/10962/d1008391
- Description: Computer operators are often required to maintain static working postures at computer workstations which have been assembled in order to accommodate the morphologies of a maximum number of operators, and these workstations generally have a limited degree of adjustability. The present study sought to investigate the effects of a Standard workstation, designed for "average" users, on an anthropometrically diverse sample of computer operators, and to assess whether physical and perceptual responses, as well as performance efficiency were dependent on stature. Further investigation assessed the influence of personalised adjustments to the Standard workstation, based on the anthropometric characteristics of the subjects, as well as the introduction of a custom-designed 'floating' wrist support, on subject responses. All subjects (n=30) were tested in each of the three workstations: Standard, Personalised and Wrist Support. The responses elicited in the Personalised and Wrist Support workstations were improved significantly when compared to the Standard workstation. Joint angles were more natural, upper trapezius EMG was reduced, standard of performance improved and perceptual responses indicated a diminished incidence of body and visual discomfort, as well as greater perceived satisfaction with these workstation dimensions. Based on the findings of this study, it is recommended that sufficient adjustability be built into workstations so that it is possible to optimally personalise them for individual operators, thereby reducing the awkward postures adopted during this static type of work.
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Cultural significance of biodiversity: the role of medicinal plants in urban African cultural practices in the Eastern Cape, South Africa
- Cocks, Michelle L, Dold, Anthony P
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141338 , vital:37963 , DOI: 10.2993/0278-0771(2006)26[60:CSOBTR]2.0.CO;2
- Description: Since the International Convention on Biodiversity in 1992 conservation biologists, ecologists and conservationists have devoted considerable attention to the conservation of biodiversity. With this has come the realization that solutions to biological problems often lie in the mechanisms of social, cultural, and economic systems. This shift has emphasized the relationship between biodiversity and human diversity, or what the Declaration of Belem (1988) calls an “inextricable link” between biological and cultural diversity. The term biocultural diversity was introduced by Posey to describe the concept denoting this link. To date this concept has been used only in reference to “indigenous people” who, as part of their traditional lifestyles, use biodiversity to sustain their cultural identity. Our research, however, demonstrates that Xhosa people (amaXhosa) living in an urban context in the Eastern Cape Province of South Africa continue to use wild plants for cultural purposes and often access these through commercial trade. We suggest that recognition of the cultural and spiritual values associated with wild plants would greatly enhance biodiversity conservation efforts. Recognition of the significant role that wild plants play in fulfilling cultural needs for urban Xhosa people would go a long way towards achieving this.
- Full Text:
- Authors: Cocks, Michelle L , Dold, Anthony P
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141338 , vital:37963 , DOI: 10.2993/0278-0771(2006)26[60:CSOBTR]2.0.CO;2
- Description: Since the International Convention on Biodiversity in 1992 conservation biologists, ecologists and conservationists have devoted considerable attention to the conservation of biodiversity. With this has come the realization that solutions to biological problems often lie in the mechanisms of social, cultural, and economic systems. This shift has emphasized the relationship between biodiversity and human diversity, or what the Declaration of Belem (1988) calls an “inextricable link” between biological and cultural diversity. The term biocultural diversity was introduced by Posey to describe the concept denoting this link. To date this concept has been used only in reference to “indigenous people” who, as part of their traditional lifestyles, use biodiversity to sustain their cultural identity. Our research, however, demonstrates that Xhosa people (amaXhosa) living in an urban context in the Eastern Cape Province of South Africa continue to use wild plants for cultural purposes and often access these through commercial trade. We suggest that recognition of the cultural and spiritual values associated with wild plants would greatly enhance biodiversity conservation efforts. Recognition of the significant role that wild plants play in fulfilling cultural needs for urban Xhosa people would go a long way towards achieving this.
- Full Text:
Regional calibration of the Pitman model for the Okavango River
- Hughes, Denis A, Andersson, L, Wilk, J, Savenije, H H G
- Authors: Hughes, Denis A , Andersson, L , Wilk, J , Savenije, H H G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7085 , http://hdl.handle.net/10962/d1012344
- Description: This paper reports on the application of a monthly rainfall-runoff model for the Okavango River Basin. Streamflow is mainly generated in Angola where the Cuito and Cubango rivers arise. They then join and cross the Namibia/Angola border, flowing into the Okavango wetland in Botswana. The model is a modified version of the Pitman model, including more explicit ground and surface water interactions. Significant limitations in access to climatological data, and lack of sufficiently long records of observed flow for the eastern sub-basins represent great challenges to model calibration. The majority of the runoff is generated in the wetter headwater tributaries, while the lower sub-basins are dominated by channel loss processes with very little incremental flow contributions, even during wet years. The western tributaries show significantly higher seasonal variation in flow, compared to the baseflow dominated eastern tributaries: observations that are consistent with their geological differences. The basin was sub-divided into 24 sub-basins, of which 18 have gauging stations at their outlet. Satisfactory simulations were achieved with sub-basin parameter value differences that correspond to the spatial variability in basin physiographic characteristics. The limited length of historical rainfall and river discharge data over Angola precluded the use of a split sample calibration/validation test. However, satellite generated rainfall data, revised to reflect the same frequency characteristics as the historical rainfall data, were used to validate the model against the available downstream flow data during the 1990s. The overall conclusion is that the model, in spite of the limited data access, adequately represents the hydrological response of the basin and that it can be used to assess the impact of future development scenarios.
- Full Text:
- Authors: Hughes, Denis A , Andersson, L , Wilk, J , Savenije, H H G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7085 , http://hdl.handle.net/10962/d1012344
- Description: This paper reports on the application of a monthly rainfall-runoff model for the Okavango River Basin. Streamflow is mainly generated in Angola where the Cuito and Cubango rivers arise. They then join and cross the Namibia/Angola border, flowing into the Okavango wetland in Botswana. The model is a modified version of the Pitman model, including more explicit ground and surface water interactions. Significant limitations in access to climatological data, and lack of sufficiently long records of observed flow for the eastern sub-basins represent great challenges to model calibration. The majority of the runoff is generated in the wetter headwater tributaries, while the lower sub-basins are dominated by channel loss processes with very little incremental flow contributions, even during wet years. The western tributaries show significantly higher seasonal variation in flow, compared to the baseflow dominated eastern tributaries: observations that are consistent with their geological differences. The basin was sub-divided into 24 sub-basins, of which 18 have gauging stations at their outlet. Satisfactory simulations were achieved with sub-basin parameter value differences that correspond to the spatial variability in basin physiographic characteristics. The limited length of historical rainfall and river discharge data over Angola precluded the use of a split sample calibration/validation test. However, satellite generated rainfall data, revised to reflect the same frequency characteristics as the historical rainfall data, were used to validate the model against the available downstream flow data during the 1990s. The overall conclusion is that the model, in spite of the limited data access, adequately represents the hydrological response of the basin and that it can be used to assess the impact of future development scenarios.
- Full Text:
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