19 research outputs found
Semantic Web Service Interaction Protocols: An Ontological Approach
No full textA central requirement for achieving the vision of run-time discovery and dynamic composition of services is the provision of appropriate descriptions of the operation of a service, that is, how the service interacts with its environment, be it agents or other services. In this paper, we use experience gained through the development of real-life Grid applications to produce a set of requirements for such descriptions and then attempt to match those requirements against the offerings of existing work, such as OWL-S [1] and IRS-II [2]. Based on this analysis we identify which requirements are not addressed by current research and produce a model for describing the interaction protocol of a service in response. The main contributions of this model are the ability to describe the interactions of multiple parties with respect to a single service, distinguish between interactions initiated by the service itself and interactions that are initiated by clients or other cooperating services, and capture within the description service state changes relevant to interacting parties that are either a result of internal service events or interactions. The aim of the model is not to replace existing work, since it only focuses on the description of the interaction protocol of a service, but to inform the further development of such work
The beach-seine fishery off Durban, KwaZulu-Natal
No full textThe beach-seine fishery at Durban was investigated from July 1993 to June 1994. During this period the fishermen completed 270 hauls on 146 days of operation. In total, 119 species of fish as well as squid, cuttlefish and crabs were recorded in the catches. Most of these were small shoaling species belonging to the families Leiognathidae, Engraulidae and Clupeidae. Many species were caught at sizes below their reported size at first maturity. Based on this study and data from the National Marine Linefish System, there appears to be little overlap in the catches of the beach-seine netters and other fishery sectors in the area
Verbal memory functioning in borderline personality disorder : neuropsychological and neuroimaging perspectives
No full textMensebach C. Verbal memory functioning in borderline personality disorder : neuropsychological and neuroimaging perspectives. Bielefeld (Germany): Bielefeld University; 2006.Clinical features of Borderline Personality Disorder (BPD) as an unstable and dysregulated control over behavior, emotion, and cognition as well as clinical descriptions of temporary disturbances of perception and cognition led to the question of neuropsychological deficits. Although neuropsychological investigations of BPD did not provide a consistent constellation of findings, some evidence is available for a non-domain-specific impairment in multiple domains of memory, attention, visuo-spatial abilities and executive functioning (Fertuck et al., 2006). The clinical features of BPD and neuropsychological findings have been repeatedly discussed as reflecting prefrontal and temporo-limbic dysfunctions. Neuroimaging research provides support for alterations within these brain areas with respect to structure and function (Schmahl & Bremner, 2006). Although often reported neuropsychological outcomes have been repeatedly interpreted as reflecting prefrontal and temporo-limbic brain dysfunctions, these interpretations have to be preliminary since little is known about neurophysiological correlates of basic neuropsychological functions in BPD. With regard to the current state of research, it was considered that further neuropsychological research could benefit by considering three major principles: (i) The investigation of basic neuropsychological functions by the use of brain imaging methods, (ii) the inclusion of neuropsychological tasks with regard to emotional relevant stimuli and affect-laden processing, and (iii) the use of neuropsychological test that consider everyday demands. With regard to these considerations, the studies presented in this thesis aimed at the comprehensive investigation of verbal memory functioning in BPD.
The first study examined the neural correlates of verbal memory retrieval in BPD compared with non-psychiatric control subjects. Some prior neuropsychological findings argued for verbal memory malfunctioning in BPD. Furthermore, brain-imaging findings support alterations in prefrontal and limbic brain areas of BPD patients. Since these brain areas have been suggested to be crucial in both, episodic (memory for events and the surrounding context) and semantic memory (memory for facts / knowledge) retrieval (Cabeza & Nyberg, 2000; Markowitsch, 2005), these brain alterations may indicate general deteriorations in memory-related brain circuits. In an fMRI experiment, regional blood oxygenation level dependent (BOLD) signals were assessed during two experimental conditions of interest (episodic retrieval: 24-hour delayed recall of a wordlist; semantic retrieval: completing a lexical fluency task) and a low level baseline (listening to MRI noise) in 18 female right-handed BPD patients and 18 non-psychiatric control subjects matched with respect to sex, age, and education. It was hypothesized that BPD patients would show increased regional BOLD responses in prefrontal and limbic brain areas during both memory retrieval conditions. Although BPD patients and control subjects showed comparable performances in verbal episodic and semantic retrieval, important group differences in regional brain activation became evident. During the retrieval of episodic information, BPD patients showed patterns of increased task-specific regional BOLD responses as compared to controls in the posterior cingulate cortex (BA 23, 31) bilaterally, in the left middle (BA 21) and superior temporal (BA 22) gyri, in the right inferior frontal gyrus (BA 45) and in the right angular gyrus (BA 39). Further, control subjects compared with BPD patients did not show areas with increased BOLD responses. During the retrieval of semantic information, BPD patients as compared with control subjects showed areas of task-specific BOLD responses with respect to the right posterior cingulate cortex (BA 31), right fusiform gyrus (BA 37), left postcentral gyrus (BA 1,2,3) and the left anterior cingulate cortex (BA 24). Again, no areas of increased task-specific BOLD responses of control subjects compared with BPD patients could be found. Despite similar neuropsychological performances of BPD patients and control subjects in episodic and semantic memory tasks the day prior to scanning, the BPD patients showed, as hypothesized, patterns of increased brain activation. However, against the hypotheses, increased regional brain activation was not only evident in prefrontal and limbic brain areas but included further parietal areas. The increased regional brain suggests that BPD patients need to recruit additional cortical resources in order to successfully retrieve information. Thus, increased activation of BPD patients during retrieval might serve as compensation ("cognitive reserve capacity") to perform on a high level comparable to controls. Therefore, increased activation might indicate additional networks for adequate retrieval needed by BPD patients, i.e. increased effort, attention, working memory, or emotional control. However, it has to be noted that the results of the brain imaging study are limited to female patients with BPD since no male were included.
Study II examined the neuropsychology of verbal memory functioning in BPD. Most neuropsychological tests used neutral stimulus material to analyze verbal memory functioning whereas everyday requirements often include a variety of emotional relevant stimuli. Further, only few studies used verbal working memory tasks, which demand the control, and inhibition of interference as required in everyday demands. Limited evidence is available suggesting that BPD patients might show a reduced inhibition of emotionally relevant interference during memory tasks (Korfine & Hooley, 2000). For a closer investigation of the impact of interference on memory performance of BPD patients, a verbal learning/interference task was developed (Beblo, Mensebach et al., 2006). This task includes besides a learning condition without interference, conditions which utilize the presentation of additional stimuli of neutral and negative valence for interference purposes. With respect to the verbal/learning interference task, an interaction effect of learning condition (without interference, neutral valenced interference, negative valenced interference) and group (BPD patients, control subjects) on memory performance was expected. BPD patients were expected to show a decreased memory performance compared with control subjects if learning includes the control and inhibition of emotional negative interference, whereas their memory performance was expected to be comparable with control subjects regarding the learning conditions with neutral valenced interference and without interference. Besides the experimental verbal learning/interference task additional standard verbal memory tests covering verbal working memory, delayed memory and semantic memory were applied to control for possible impairment of the BPD patients with regard to standard conditions. 32 (21 females, 11 male) patients with BPD and 35 (23 females, 12 males) non-psychiatric control subjects matched with respect to sex, age, and intelligence took part. The results showed the hypothesized constellation of findings. Whereas memory performance of BPD patients were comparable with the control subjects regarding the learning conditions without interference and with neutral interference, BPD patients showed a significant decrease of memory performance as compared to control subjects in the condition with interference of negative valence. No group differences were found in the further neuropsychological tests, which were applied covering verbal working, delayed and semantic memory performance. These results suggest no general impairment of verbal memory functions in BPD. However, BPD may be characterized by a selective impairment of interference control and inhibition in BPD regarding emotional negative stimuli during learning.
The investigation of memory functioning with brain imaging method as well the inclusion of conditions, which require interference control and inhibition, can be characterized as helpful in the understanding of neuropsychological functions in BPD. The present findings may lead to the conclusion that verbal memory functioning is less severe than once thought. Furthermore, the efforts of the present studies made an important contribution to a more concrete determination of possible mechanisms that are impaired during the processing of memory tasks in BPD.
In sum, the present studies yielded three major findings: Verbal memory dysfunctions of BPD patients may be less severe impaired than once thought. The use of standard neuropsychological tests suggested no general impaired verbal memory functioning in BPD. However, BPD patients may use additional brain resources during the retrieval of verbal memory contents to perform on a level comparable to control subjects. Further, BPD patients show a reduced control for interference and inhibition during learning. More specifically, the reduced interference control and inhibition during verbal learning was restricted to emotionally relevant stimuli
NATURAL RESOURCE ACCOUNTING AND SOUTH AFRICAN FISHERIES: A BIO-ECONOMIC ASSESSMENT OF THE WEST COAST DEEP-SEA HAKE FISHERY WITH REFERENCE TO THE OPTIMAL UTILISATION AND MANAGEMENT OF THE RESOURCE
No full textResource /Energy Economics and Policy,
Modelo baseado em agentes em apoio à solução de problemas de não-conformidades em ambientes de manufatura com recursos distriubídos
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia MecânicaNos últimos anos, a necessidade de atuar em um âmbito de negócios globais, bem como atender a requisitos crescentes em relação à qualidade, diversidade e custo, têm levado as empresas de manufatura a buscar novas estruturas organizacionais como alternativas aos sistemas tradicionais centralizados. Este cenário globalizado vem induzindo novas formas de competição, que deixam de ser somente entre empresas individuais, e passam a ser também entre redes de empresas interconectas e que operam em ambientes de manufatura com recursos distribuídos. Neste cenário, novos desafios também são impostos aos modelos tradicionais de gestão e melhoria da qualidade, os quais devem ser capazes de cobrir não somente processos internos de uma única empresa, mas estender-se também aos processos externos envolvendo as empresas interconectadas. Nestes novos ambientes, em especial, a solução de problemas de não-conformidades caracteriza-se por atividades intensivas em conhecimento e baseadas, fortemente, em experiências, as quais, em casos complexos, podem extrapolar o conhecimento e a experiência dos membros de uma única empresa integrada. Tendo em vista este contexto, esta tese investiga o uso da abordagem de organizações multiagentes destinadas ao compartilhamento e a recuperação de conhecimentos decorrentes da solução de problemas prévios de não-conformidade e da aplicação do método preventivo de análise de modos de falha e efeitos em processos de manufatura (PFMEA). Neste sentido, propõe-se um modelo de organização multiagente em apoio à solução de problemas de não-conformidades em processos de fabricação, como uma alternativa capaz de superar não somente as barreiras relacionadas à própria natureza do conhecimento, mas também quanto à distribuição das fontes deste conhecimento. A noção de distribuição adotada no modelo considera tanto o aspecto da distribuição geográfica das fontes quanto à fragmentação relacionada aos diferentes processos existentes ao longo de uma cadeia de produtiva. Dentro desta ótica, serão considerados no modelo agentes computacionais cujo comportamento envolve o uso de métodos de raciocínio baseado em casos e métodos de recuperação baseada em ontologias. Por fim, um protótipo computacional foi desenvolvido para permitir a verificação e a validação do modelo proposto, sendo que as bases de conhecimento manipuladas pelos agentes foram instanciadas com conhecimentos no domínio do processo de moldagem por injeção de termoplásticos obtidos a partir da literatura e de pesquisas de campo
Coping with asthma : investigation and intervention using the self-regulation model
No full textThe Self-Regulation Model (Leventhal, Nerenz & Steele, 1984)
highlights the roles of patients' illness representations, coping, emotional
reactions and appraisal of coping in the progression of chronic disease. This
thesis incorporates previous literature on adherence, panic-fear and selfmanagement
interventions into the model in order to (a) investigate coping
with asthma and (b) develop an intervention aimed at improving asthmatic
control.
New measures of asthmatic control and illness representations of the
consequences of having asthma were developed in order to operationalise the
model.
A cross-sectional study investigated factors influencing asthmatic
control in a sample of 35 adult asthma sufferers recruited through a single
general practice. Coping was poor, adherence being low and less than 50% of
participants reporting current Peak Flow monitoring or medical contact
during the previous 12 months. Good coping appeared to be a response to
poor asthmatic control, rather than prophylactic. Good asthmatic control was
associated with low perceived consequences, recent medical contact, moderate
panic-fear and low general avoidance coping. These results imply that
asthmatic control may be improved by encouraging sufferers to maintain
regular contact with outpatient services and to implement prophylactic
coping.
Since epidemiological and clinical evidence suggested asthmatic
control to be poor in young adults, an intervention was developed to
improve asthmatic control in this group by modifying illness representations,
coping and panic-fear. The intervention was evaluated in a randomised
controlled study of 50 student asthma sufferers identified initially through an
epidemiological screening of 2,979 students. It led to increased Preventer
medication use and Peak Flow monitoring and decreased distress over the
condition. However, the coping process changed and asthmatic control
improved even in the control group, perhaps because self-monitoring of
asthmatic control for the study constituted a change in coping. This
unanticipated result was entirely compatible with the Self-Regulation Model.
The thesis dearly demonstrates value of the Self-Regulation Model in
understanding asthma self-management and developing clinical
interventions
Telomere Length and Distribution in Three Developmental Stages
No full textTelomeres are specialised nucleoprotein structures present at the ends of each chromatid that function to maintain genome stability. It is well established that a gradual decline in telomere length is associated with the process of cellular ageing, and thereby to the pathobiology of age-related diseases. In addition, the localisation of the telomere at the nuclear periphery plays an important role in the spatio-temporal organisation of the genome and in ensuring faithful segregation of chromosomes during meiosis. The aims of this thesis were to investigate telomere localisation in the nucleus, and telomere length in three hitherto early stages of development, gametogenesis, preimplantation embryogenesis and the neonatal period. Specifically:
1. To test the hypothesis that telomeres localised at the nuclear periphery in sperm cells and that this organisation was altered in sub-fertile men
2. To optimise a means of assessing average telomere length using DNA from small sample sizes and using whole genome amplified DNA from single cells
3. To investigate the role of telomere length in reproductive ageing and aneuploidy generation in women by testing the hypothesis that telomere length is significantly shorter in the first polar bodies and cleavage stage embryos of older women
4. To test the hypothesis that “preterm at term” babies (i.e. premature babies assessed at the time of their due date) displayed genetic signs of premature ageing (as manifested by significantly shorter telomeres than their term born counterparts) alongside the already established clinical signs (characterised by hypertension, diabetes and altered body fat distribution)
Results confirmed the peripheral distribution of telomeres in the sperm heads of normally fertile males (using both 2D and 3D imaging) plus the novel finding that telomere distribution patterns are altered in the sperm heads of infertile males. Secondly, a reliable means of measuring telomere length was optimised in order to assess average telomere length using DNA from small sample volumes (down to single cells). Using this technology, average telomere length analysis in polar bodies and embryos found no evidence to support the hypothesis that telomere length is associated with either advanced maternal age or aneuploidy generation. Similarly, results suggest that telomere length is not significantly shorter in “preterm at term” infants compared to term born controls, thus providing no evidence that telomere attrition is involved in the pathobiology of the ‘aged phenotype’ observed in preterm infants. Taken together, results from this thesis provide some novel insights into the function of these highly important features of the genome, but also highlight that a great deal remains to be uncovered in the complex molecular mechanisms that contribute to the regulation of telomere length and nuclear distribution
The short-term effect of rehabilitation on ecosystem services in the semi-arid succulent Karoo lowlands and the Little Karoo, South Africa
No full textThis study has shown that using active rehabilitation in combination with improved management strategies (e.g. rest from grazing) may induce recovery of certain ecosystem services within practically relevant time scales. However, these benefits might not be tangible for landowners or society as of yet, due to the small-scale nature of the rehabilitation application along with the relatively high, short-term associated costs. To alleviate financial constraints on farmers and in order to socially and financially enhance local communities, the focus for now should be on sourcing funds from government and private sectors for rehabilitation implementation
