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

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

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

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

The elements of job evaluation in the development of a pay structural comparison system guide to conducting compensation surveys to determine competitive adjustments to base salary ranges

If the wage policy of an organisation is to remain competitive in the labour market, that is, pay rates that are at least approximately equal to those prevailing in the community, then it must collect accurate wage and salary data in order to alter its pay structure as may become necessary. Wage and salary survey information provides a means by which management can determine whether its entire wage level is in accordance with that of the external labour market, and thus it is absolutely essential that methods and techniques utilised to collect such information are as objective and accurate as possible. The vital factor which has been revealed by the utilisation of many existing wage and salary survey guides is that the unavoidable subjectivity involved in the basic techniques utilised in survey procedures tends to have a cumulative effect on both data collection and analysis, and ultimately interpretation. As each technique is utilised, whether it be to obtain job comparability or to adjust salary data, the overall level of subjectivity is increased, which results in a cumulative increase in the margin of error involved in data collection. This study has been aimed at developing and practically testing a comprehensive guide to conducting wage and salary surveys which effectively minimises and, over successive surveys, eradicates the necessity for these subjective techniques. Due to the fact that the elements of job evaluation, namely, job analysis, job description, job specification and the job evaluation plan itself, form the nucleus of the techniques utilised for the data gathering and analysis process, the initial study was aimed at developing a job evaluation process which would be as objective as possible. In the development of such a system a range of job evaluation plans were tested for comparability in rating of jobs, the hypothesis being that any evaluation method or plan, when correctly applied to a series of jobs, will result in the same classification. This study intercorrelated rates derived for twenty-four key jobs selected from one particular organisation, using the job evaluation methods utilised by sixteen different organisations, and found that these rates intercorrelated between 0,93 to 0,99. These intercorrelations indicate a high degree of commonality among the sixteen methods; thus providing a justification for the utilisation of one particular job evaluation plan for the adjustment and weighing of wage and salary data in the survey data analysis procedure. To further justify the utilisation of one particular method, and thereby increase probability of acceptance by participating organisations, the independence of the sub-factors of the selected plan were tested by intercorrelating the factor scores for two job samples, one consisting of sixty jobs, type and level being heterogeneous, the other consisting of forty jobs, type and level being homogeneous. Sub-factor intercorrelations in the group of heterogeneous jobs ranged from 0,71 to 0,98 while all but one correlated at or above 0,90 with the total score, thus emphasising the independence of sub-factors, while intercorrelations in the group of homogeneous sample were much lower, ranging from 0,26 to 0,89, indicating greater factorial independence due to the fact that these jobs are limited to a narrower range of grades such that specific job differences in respect of sub-factors are more likely to show up. Utilising this selected job evaluation plan as the core of the developed job evaluation process, a wage and salary survey guide was formulated, the unique concept being a comparison of participating organisation pay structures rather than comparison of positions as a basis for data collection. The job evaluation system was utilised in the formulation of a "one-time" standardisation of participating organisation pay structures according to the survey organisation pay structure, the hypothesis being that these standardised pay structures may be utilised over successive surveys without the necessity for restandardisation, and thus eliminating the use of subjective methods and techniques subsequent to the initial standardisation. Utilising an international oil company as the survey organisation this newly formulated structural comparison guide was practically tested by applying it in conjunction with the existing survey organisation wage and salary survey guide as a means of competitive market wage and salary data gathering and analysis, over successive survey years, namely, 1974, 1977, and 1980. The results obtained through application of this guide were subsequently compared with those results obtained by two professional survey organisations, and proved to be reliable and consistent enough over the applicable survey years to warrant acceptance of the pay structural comparison concept as a valid wage and salary survey technique