Carbon dioxide exchange in lichens: Relationship between the diffusive resistance of carbon dioxide and water vapour

Gaseous diffusion resistances for carbon dioxide and water vapour, thallus water content and thallus water potential were experimentally determined on species of the Stictaceae. The diffusion resistance to water loss was high only at low water contents and correlated closely with thallus water potential. Carbon dioxide diffusion resistances, however, were high at both low and high water contents and, even at medium water contents, were still an order of magnitude greater than the water resistance. These results indicate that carbon dioxide and water vapour exchange occur by different pathways in these lichens. Consequently it is suggested that the lichens have structural adaptations which separate the functions of water uptake, water storage and carbon dioxide exchange

A provisional survey of the interaction between net photosynthetic rate, respiratory rate, and thallus water content in some New Zealand cryptogams

The effect of water content on photosynthetic and respiratory rates in eight lichen species and one bryophyte species were studied using an injection infrared gas analyser technique. All species snowed a strong relationship between net assimilation rate (NAR), respiration rate, and water content similar to relationships reported in published studies overseas. Species from moist habitats showed negative NAR at low water contents. Species from high-light areas showed a depression in NAR at high water contents which could be alleviated by higher light intensities. The experiments confirmed the suitability of New Zealand species for these studies

Flowering of kiwifruit (Actinidia deliciosa) is reduced by long photoperiods

Mature kiwifruit (Actinidia deliciosa ‘Hayward’) vines grown under standard orchard management were exposed to 16-h photoperiods from the longest day in summer until after leaf fall in autumn. Photoperiod extension was achieved with tungsten halogen lamps that produced 2–8 µmols m–2 s–1 photosynthetically active radiation. Long day treatments did not affect fruit dry matter or fruit weight at harvest during the growing season that the treatments were applied or during the following growing season. However, flowering was reduced by 22% during the spring following treatment application. As this reduction in flowering was not accompanied by a decrease in budbreak, the long day effect is not consistent with a delay in the onset of winter chilling. It is suggested therefore, that the observed reduction in flowering may be because of a diminution of floral evocation

Implementing Industry Best Practice Alarm Management

This dissertation investigates how alarm management practices can be implemented at a large industrial facility, and what effect this could have on alarm system performance. Poor performing alarm systems create an environment where alarms of high importance can be missed or operators are desensitised to the alarm system. Alarm system performance has been a factor in several high consequence industrial accidents. The project was conducted at a large coal fired power plant which uses modern Process Control and Human Machine Interface systems. The project site has never employed any alarm management practices in the past and is seeking to implement alarm management practices based on ISA-18.2-2009 Management of Alarm Systems for the Process Industries. The requirements of industry best practice alarm management were researched and identified. Alarm management processes were created and adopted by the project site. New software tools were developed to support the alarm management processes. The alarm system performance at the project site was measured using these software tools. The worst performing alarms over a six month period were identified. By investigating the causes of the worst performing alarms improvements were identified that could reduce the alarm rate by 40%

The eco-physiology of New Zealand forest lichens with special reference to carbon dioxide exchange

This study of lichen ecological physiology was carried out in four parts: (i) The growth rates of specimens of Pseudocyphellaria homoeophylla and Sticta caperata growing in the Urewera National Park (New Zealand) were measured photographically. The mean radial increase of P. homoeophylla was related to thallus diameter and rates as high 27 mm yr⁻¹ (32 cm diameter) were recorded. The growth of S. caperata was not influenced by thallus size and the mean radial increase was 7.0 mm yr⁻¹. (ii) The intraspecific morphological variations of Pseudocyphellaria dissimilis populations are assessed and are related to the nitrogenase activity and water relations of each population. The effect of thallus water content on CO₂ exchange in eight lichen and one bryophyte species was studied using an infrared gas analyser operating as a discrete sample analyser. Species from moist habitats showed a net loss of CO₂ at low thallus water contents whilst some other species showed a depression of net photosynthesis (NP) at high thallus water contents. In Sticta latifrons this depression was less apparent when the lower surface was dried. Experiments with a split chamber demonstrated that virtually all CO₂ uptake occurs through the lower, cyphellate surface. These results suggest that the cyphellae of S. latifrons act as air pores and that blockage of these pores with water results in a depression of NP. (iii) Low oxygen concentrations (1% v/v) were shown to increase NP in S. latifrons, P. homoeophylla and P. billardierii by up to 55%. This stimulation was considered to result from the repression of photorespiration. The oxygen effect was separated into two components; (a) the sensitivity of the carboxylation system and (b), the rate of CO₂ evolution in the light at zero CO₂. Of the lichen species studied all but P. billardierii had a carboxylation sensitivity typical of the values expected in C3 plants. P. billardierii had an unusually low carboxylation sensitivity. The rate of CO₂ evolution in the light showed large inter and intraspecific variations. Low rates of CO₂ evolution were often associated with a high CO₂ refixation ability. (iv) Total CO₂ diffusion resistance - water content curves for six lichen species are presented. All species show increased resistances at low thallus water contents and some also show high resistances at high thallus water contents. The total CO₂ resistances of S. latifrons and P. amphisticta are separated into transport and carboxylation components. Cyphella, pseudocyphella, and medulla resistances are calculated from morphological data. Although transport resistances are often larger than carboxylation resistances the results suggest that at ambient CO₂ levels carboxylation processes limit photosynthesis. The relationship between resistance to water vapour loss and resistance to CO₂ uptake in P. homoeophylla and S. latifrons is established and the ecological implications are discussed. In a general summary, the size of the internal and external water holding capacities of several lichen species is estimated. The effectiveness of these reserves in maintaining lichens in a moist condition in the field is calculated and the results are related to the ecology of the species. Morphological adaptations of Stictaceae lichens which maximise water holding capacity yet minimise CO₂ diffusion resistances are considered. It is suggested that lichen water contents should be related to thallus area, rather than thallus weight, as the former parameter appears to be of greater physiological significance. The relevance of this work to that of previous authors is discussed, particularly in regard to photorespiration, CO₂ uptake, and thallus water content in lichens

Psychologists' and psychiatrists' opinions on cluster B personality symptomology in children and adolescents.

The diagnosis of personality pathology in children and adolescents has increasingly become an area of interest in study and literature internationally. However, this topic is a much debated one among professionals whereby the validity and utility of this diagnosis has been questioned. This paper explores these arguments. The research follows that of two previous studies conducted in Johannesburg hospitals which found a prevalence of personality pathology being noted on Axis II of adolescent case files, specifically the Cluster B diagnoses. This study investigated Psychologists and Psychiatrists opinions on what symptoms are being seen in children and adolescents that warrant the notation of personality pathology on Axis II. This study focussed on the symptomology profile of the Borderline, Narcissistic and Antisocial diagnoses, differences in symptom notation between children and adolescents, and respondents opinions on the applicability of the DSM-IV-TR to personality disorder assessment in this age demographic, as well as whether or not professionals in this study preferred to note symptoms individually or as relevant to Cluster B presentations overall. A questionnaire was constructed and Descriptive statistics were used. The research questions were tested using frequency counts, analysis of variance (ANOVA) and covariance (ANCOVA). The findings of this study demonstrate that professionals feel more able to make note of personality symptomatology in adolescents than they do in children, and that the notation of Borderline symptoms by respondents exceeded that of any other group. Furthermore, respondents more frequently endorsed the use of individual symptoms for each group, over that of using a general Cluster B notation and finally, it was found that the majority of participants believe adjustments should be made to future revisions of the DSM-IV-TR

An empirical study of the reward preferences of South African employees

Orientation: Adapting traditional reward systems to focus on employee preferences has become a necessity as companies strive to attract, motivate and retain a skilled and high performing workforce. Research purpose: The aim of the study was to identify certain categories of rewards that employees consider to be most important, including base pay, contingency pay, benefits, performance and career management, quality work environment, and work–home integration. The impact of these reward categories on an organisation’s ability to attract, motivate and retain employees was explored, together with the influence of demographic variables on reward preferences. Motivation for the study: There is much debate over whether reward packages should be tailor-made to suit individual employees. It has been argued that a ‘one-size-fits-all’ approach with regard to rewards is no longer effective. Research design, approach and method: A structured questionnaire, based on the total rewards model, was used to achieve the objectives of the study. A sample of 250 employees from 11 medium-sized to large-sized organisations participated in the study. Main findings: The results showed that base pay is deemed to be the most preferred reward component amongst respondents; however, they are most dissatisfied with the level at which this reward is provided by their current employers. Base pay is also the most important reward when attracting and retaining employees. Differences between reward preferences and demographic variables, including age, gender and job level, were found. Practical/managerial implications: Organisations should design their reward systems according to the preferences of their employees by focusing on base pay and contingency or variable pay. These rewards will also serve to retain them; although, to motivate employees, non-cash awards and recognition should be emphasised. Contribution/value-add: This study contributes to literature on reward preferences, which is lacking in a South African context. It also provides support for segmentation of rewards based on certain demographic variables

The effectiveness of sandplay therapy with a Xhosa child

This case study sought to determine whether Kalffian Sandtray Therapy was effective with a Xhosa child. In the context of ongoing discussions surrounding evidence-based practice and culturally appropriate interventions, no published research has yet explored the effectiveness of this classical tool within this significant South African demographic. In an effort to address this omission, the research adopted a mixed methods approach where Kalffian analysis of the sandplay process was evaluated in conjunction with quantitative measures (the Strengths and Difficulties Questionnaire and the Young Person’s Clinical Outcomes in Routine Evaluation). The results of this triangulation revealed a complex picture of improved interpersonal functioning and stagnant (or worsened) emotional wellbeing after five sessions. Contextualised interpretations of these findings are discussed and recommendations made for future sandplay practice and research in the South African context

The motivational value of rewards amongst Malawi’s health professionals

Orientation: Reward administrators of Malawi’s health sector seem to misunderstand the intrinsic and extrinsic values of financial and non-financial rewards. Research purpose: This study focuses on assessing the motivational value of rewards amongst health professionals in Malawi’s Ministry of Health (MoH). Motivation for the study: Malawian studies indicate that Malawi’s MoH has become dysfunctional largely due to reward-related problems faced by its health professionals. Research design, approach and method: This study was a non-experimental design with an explanatory and evaluative approach, utilising both quantitative (questionnaire) and qualitative methods (literature review, interviews and focus group discussions). Main findings: The study confirmed the existence of reward-related problems amongst health professionals in Malawi’s MoH. Initially, statistical testing of the hypothesised model collapsed, suggesting that no relationship existed amongst the variables. However, statistical testing of the re-specified model suggests that there is a positive relationship between financial and non-financial rewards. Through the structural equation modeling (SEM) exercise, an inverse (negative) relationship between financial and non-financial rewards was established. Practical/managerial implications: The re-specified model symbolises a pragmatic departure from theoretical claims that financial rewards (salaries or money in general) are not a motivator. The graphic model suggests to managers and policy-makers that both financial and non-financial rewards are very important and valuable in any employment relationship. Contribution/value-add: An inverse (causal) relationship between financial and non-financial rewards has been established, graphically demonstrated and scientifically explained