A new sabellid that infests the shells of molluscs and its implications for abalone mariculture

Bibliography: leaves 76-87.Infestations of sabellid polychaetes were found in South African farmed abalone in 1994. Growth experiments confirmed that infested abalone had reduced growth rates. Surveys of both the intertidal and subtidal region at various locations around the South African coastline revealed that the sabellid was endemic to the region. It occurred in a range of mollusc species, but some species were more susceptible than others. The fact that some molluscan species became infested with worms only when exposed to them in the laboratory suggests that environmental factors may play a role in controlling natural levels of infestation. Different host selection on the East Coast of South Africa suggests that there may be more than one species of worm. Larvae disperse by crawling and settle at the growing edge of the shell underneath the mantle. Although the larvae are benthic, there is limited transfer of larvae through the water column, which can result in export of larvae from infested tanks. The risks of dispersal are discussed in a farm management context. Abalone kept in more hygienic laboratory conditions tended to grow faster than in farm tanks and had lower levels of infestation by sabellid larvae. This was attributed to the sabellids being less fecund under these conditions. This was probably caused by lack of food as evidenced in a separate starvation experiment. Based on experimental observations and farm experience it was possible to make management recommendations to limit the effect of the sabellid Quantitative measurement taols to assess the impact and productivity of sabellid infestations were developed Management of infestations on a farm requires a combination of inhibiting transfer and productivity of the worm and also promoting growth of the abalone. However, the constant risk of exposure to natural populations of sabellids necessitates the development oJ a treatment to eradicate sabellid infestations. The use of microcapsules as a drug delivery mechanism was explored and holds promise. Gelatin microcapsules, oil immulsions and liposomes were experimented with. All formulations were successfully produced in the desired size range of 2-30 μm. In all cases the sabellid'l readily ingested the capsules. Various toxins were successfully added to the formulations, but none of the treatments were able to harm the sabellids. The problem appeared to be the short passage time within the guts and the inability of the sabellids to digest the outer encapsulating layers to expose the toxins. More research is required to find the correct combination of toxin and delivery mechanism

Tate Homology and Powered Flybys

In this paper we show that in the planar circular restricted three body problem there are either infinitely many symmetric consecutive collision orbits or at least one periodic symmetric consecutive collision orbit for all energies below the first critical energy value. Using Levi-Civita regularization allows us to distinguish two different kinds of symmetric consecutive collision orbits and prove the above claim for both of them separately, one corresponding to a solar eclipse and the other to a lunar eclipse. By interpreting the orbits as Hamiltonian chords between two different Lagrangian submanifolds we can use a perturbed version of $G$-equivariant Lagrangian Rabinowitz Floer homology to prove the existence of this kind of consecutive collision orbit. To calculate this homology we show that under certain conditions the $G$-equivariant Lagrangian Rabinowitz Floer homology is equal to the Tate homology of $G$.Comment: 17 pages; assumption for Theorem 5.6 changed and subsequent corrections adde

Informed Employee Voice: The Synthesis of Internal Corporate Communication and Employee Voice and the Associations with Organisational Engagement

This thesis aims to advance knowledge about internal communication and organisational engagement. It incorporates the application of a new research instrument, the Internal Communication and Organisational Engagement Questionnaire (ICOEQ) developed by Welch (2011a). The ICOEQ investigates employee interest in different topics, helpfulness of communication methods used, ratings for senior manager and line manager communication, satisfaction with employee voice and the associations with organisational engagement. Despite the importance of internal communication, existing research methods are limited as they do not adequately distinguish between different dimensions of internal communication as established by Welch and Jackson (2007, p.184) and they fail to make an association with organisational engagement. The ICOEQ therefore provides a new research perspective for academic researchers and communication managers. The conceptual analysis builds on Welch and Jackson’s (2007, p.185) internal communication matrix. It synthesises corporate communication and employee voice into a new concept, informed employee voice, to reflect the importance of keeping employees informed and giving them a voice that is treated seriously. The empirical work adopts a critical realism approach. A cross-sectional research design was used. The ICOEQ was administered at five organisations followed by interviews and focus groups. Quantitative data analysis suggests that internal communication is more strongly correlated with emotional organisational engagement than with cognitive or behavioural organisational engagement. Ratings of senior manager communication and line manager communication and satisfaction with employee voice are positively associated with organisational engagement. Standard multiple regression analysis indicates that informed employee voice is a significant predictor of organisational engagement. Template analysis of qualitative data indicates that many senior managers are not visible or approachable and they do not listen to what employees have to say. New themes that emerge include more informal and small group communication with senior managers, a greater focus on the local context of internal corporate communication from line managers and more emphasis on listening and responding to employee voice. Possible explanations for the findings include a focus on shareholder value and the consequential neglect of employee value and the marginalisation of internal communication in academia and practice. Theoretical implications include the adoption of employee voice more fully into internal corporate communication theory, the addition of familiarity as an attribute of internal communication media and the identification of three explanatory factors for the exercise of internal ‘power over – dominance’. Above all, the thesis establishes informed employee voice as an antecedent to organisational engagement. The implications for practice include the establishment of the ICOEQ as a useful measurement tool and the requirement for communicative leadership that includes giving employees a voice that is treated seriously

A comparison of various seaweed-based diets and formulated feed on growth rate of abalone in a land-based aquaculture system

The effects of different diets on growth in the cultured South African abalone, Haliotis midae (Linnaeus), was investigated. Growth of juvenile Haliotis midae was monitored on a commercial abalone farm over a period of 9-months in an experiment consisting of 9 treatments with 4 replicates (n = 250 individuals per replicate). The treatments were: fresh kelp (Ecklonia maxima) blades (seaweed control); Abfeed® (formulated feed control); kelp + Abfeed®; dried kelp pellets; dried kelp blades; dried kelp stipes; fresh kelp with the epiphyte Carpoblepharis flaccida; a mixed diet (Gracilaria gracilis, Ulva lactuca, and kelp) and a rotational diet (abalone were fed 1 of the 9 treatments for the first week and them kelp for the next 3 weeks). Results show that abalone grow well on all fresh seaweed combinations, but do best on a mixed diet. The likely reason for the success of the mixed diet is that the red and green seaweed was farm grown, with an increased protein content. Dried kelp in any form produced poor growth. Abalone fed on the mixed diet grew at 0.066 mm day־¹ shell length and 0.074 g day־¹ body weight; this corresponds to 24.09 mm shell length and 27.01 g body weight increase per annum. Abalone fed on dried kelp grew at only 0.029 mm day־¹ shell length and of 0.021 g day־¹ body weight. Abalone grown on Abfeed® grew at 0.049 mm day־¹ shell length and 0.046 g day־¹ body weight which corresponds to 17.88 mm and 16.79 g increase per annum; this is better than the dried seaweed feeds, but poorer than the fresh seaweed combinations. This study shows that seaweed diets, particularly if the diets include seaweeds grown in animal aquaculture effluent, are good substitutes for the formulated feeds generally used today.Web of Scienc

Employee voice: An antecedent to organisational engagement?

Employee engagement is recognised as important for organisational effectiveness and a factor in achieving innovation and competiveness. Despite the importance of engagement, relatively little research has yet been done on communication and engagement. This paper aims to contribute to knowledge in this area by providing insight on internal communication and organisational level employee engagement. The paper reports the results of a study exploring associations between aspects of internal communication and organisational engagement. Taking an employee-centric approach, the paper investigates employee satisfaction with opportunities to exercise their voice, and assesses employee views on the quality of senior management receptiveness to employee voice. The paper aims to address gaps in the literature by exploring potential associations between employee voice and organisational engagement. A questionnaire was used to gather data from 2066 participants in five UK-based organisations. The questionnaire used in the study was designed to explore satisfaction with upward employee voice and senior management receptiveness. It also enables exploration of the relationship between upward employee voice, senior manager receptiveness and emotional organisational engagement. A significant and positive relationship was found between upward employee voice and emotional organisational engagement; and between senior manager receptiveness and emotional organisational engagement. Regression analysis suggests that the majority of the employee voice variables included in the study predict emotional organisational engagement. While the study involved data collected from a reasonably large number of participants, it was limited to five UK-based organisations. The paper includes reflection on practical implications of the findings for internal communication management. In particular, it considers implications for senior management communication with employees including building employee voice into internal corporate communication strategies and plans. Suggestions for further research are included. The paper contributes to employee engagement literature by expanding insight on organisational engagement. Since relatively little previous research has considered the interplay between internal communication, organisational engagement and employee voice, the study makes a useful contribution to an under-researched area

Pattern recognition receptor-mediated cytokine response in infants across 4 continents⋆

Background Susceptibility to infection as well as response to vaccination varies among populations. To date, the underlying mechanisms responsible for these clinical observations have not been fully delineated. Because innate immunity instructs adaptive immunity, we hypothesized that differences between populations in innate immune responses may represent a mechanistic link to variation in susceptibility to infection or response to vaccination. Objective Determine whether differences in innate immune responses exist among infants from different continents of the world. Methods We determined the innate cytokine response following pattern recognition receptor (PRR) stimulation of whole blood from 2-year-old infants across 4 continents (Africa, North America, South America, and Europe). Results We found that despite the many possible genetic and environmental exposure differences in infants across 4 continents, innate cytokine responses were similar for infants from North America, South America, and Europe. However, cells from South African infants secreted significantly lower levels of cytokines than did cells from infants from the 3 other sites, and did so following stimulation of extracellular and endosomal but not cytosolic PRRs. Conclusions Substantial differences in innate cytokine responses to PRR stimulation exist among different populations of infants that could not have been predicted. Delineating the underlying mechanism(s) for these differences will not only aid in improving vaccine-mediated protection but possibly also provide clues for the susceptibility to infection in different regions of the world

Valuing internal communication; management and employee perspectives

Effective internal communication is a prerequisite for organisational success. Organisations need to evaluate and improve communication especially in increasingly difficult economic pressures. Assessment instruments enable organisations to monitor communication effectiveness. This review of academic and consultancy studies found over reliance on measuring satisfaction with the communication process. The analysis found management-centric rather than employee-centric approaches to assessment. This indicates a need to develop new approaches to assessing internal communication. A conceptual model is proposed here to encourage focus on employee communication needs in terms of content as well as channel. Future approaches to assessment should draw on a wider theoretical and conceptual framework. Assessment instruments need to reflect advances in practice. They need to assess the value of internal communication to employees as well as their organisations

Insight and equality: A systematic review and meta-analysis of socio-demographic associations

BACKGROUND: Insight into illness is often used in clinical and legal contexts, for example, as evidence of decision-making capacity. However, it is unclear whether this disadvantages certain groups protected under equality legislation. To our knowledge, this question has yet to be addressed systematically. Therefore, the present study reviews empirical studies that look at the relationship between insight and sociodemographic variables. METHODS: A systematic search of six bibliographic databases (CENTRAL, CINAHL, Cochrane Library of Systematic Reviews, EMBASE, MEDLINE and PsycINFO) was conducted, which yielded 6,192 results. Study characteristics and outcomes (associations between insight and socio-demographic variables) were then extracted from 207 eligible studies. This included protected characteristics under the Equality Act (2010): age, sex, ethnicity, marital status and religion. Weighted confidence estimates were calculated and relevant moderators included in a random effects meta-analysis. A study protocol was registered prospectively on PROSPERO, ID: CRD42019120117. RESULTS: Insight was not strongly associated with any sociodemographic variable. Better insight was weakly but significantly associated with white ethnicity, being employed, younger age and more years of education. The age associations were mostly explained by relevant moderating variables. For people with schizophrenia, the associations between sociodemographic variables and insight were comparable to associations with decision making capacity. CONCLUSIONS: Our results suggest that insight is not strongly associated with any sociodemographic variables. Further research is needed to clarify potential associations, particularly with non-white ethnicity and proxies for social support