Sex Reversal of Tilapia in Earthen Ponds

This Aquacultural Production Manual from the International Center for Aquaculture at Auburn University is oriented towards field application rather than rigorous scientific evaluation of the described techniques. The management practices have been field tested and proven feasible at the described scale of production. The intended readers are intermediate to upper level technicians with experience in related aquacultural activities. As such, a basic understanding of the principles of aquatic production and of the life history and environmental requirements of tilapia is presumed

The effect of cannabis use on prospective memory processes in young adults

Remembering to perform an intended task at the appropriate time (prospective memory) is an important aspect of memory functioning in the real world. Previous research has suggested that recreational drug use has a detrimental effect upon this ability. To date relatively few studies have investigated the effect of cannabis use on prospective memory performance. In addressing this hiatus, the present thesis extended this initial research to encompass three aims. Firstly, the thesis evaluated the psychometric properties of an objective prospective memory video procedure in order to mitigate criticisms associated with the use of self-report assessment of memory failures in many of these initial studies. Secondly, the thesis documents a series of quasi-experimental studies comparing cannabis users and non-users in order to examine the effect of cannabis use on prospective memory. Finally, the thesis explored the nature of the deficits observed in an attempt to better understand the neurobiological vulnerability of the cognitive processes underpinning prospective memory to the psychopharmacological effects of cannabis. The findings across all of the studies documented suggested that cannabis use, even in relatively light users with short duration of use, has a detrimental effect on prospective memory in young adults. In addition, the findings presented suggested that the deficits observed in current cannabis users recover on cessation of cannabis use and that time-based prospective memory was more vulnerable to the effects of cannabis use than event-based prospective memory. Furthermore, the findings presented suggested that these deficits arise as a consequence of problems in retrieval of the intentions rather than problems in their encoding and that these retrieval problems arise as a consequence of failures in cue identification rather than problems retrieving the task to be performed. The findings presented found no evidence that the prospective memory deficits observed were related to the number of joints smoked per week, duration of use, estimated lifetime consumption or to the age at which cannabis use commenced. Although the scale of the deficits appeared trivial with cannabis users recalling, on average, only two items fewer than nonusers, the magnitude of the effect was moderate suggesting practical significance, particularly as the deficits were observed in independent cohorts comprising cannabis users with light use and relatively short duration of use.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Variability in ice motion at a land-terminating Greenlandic outlet glacier: the role of channelized and distributed drainage systems

We use a combination of field observations and hydrological modelling to examine the mechanisms through which variability in meltwater input affects ice motion at a land-terminating Greenlandic outlet glacier. We find a close agreement between horizontal ice velocity, vertical ice velocity and modelled subglacial water pressure over the course of a melt season. On this basis, we argue that variation in horizontal and vertical ice velocity primarily reflects the displacement of basal ice during periods of cavity expansion and contraction, a process itself driven by fluctuations in basal water pressure originating in subglacial channels. This process is not captured by traditional sliding laws linking water pressure and basal velocity, which may hinder the simulation of realistic diurnal to seasonal variability in ice velocity in coupled models of glacial hydrology and dynamics

A temperate former West Antarctic ice sheet suggested by an extensive zone of bed channels

Several recent studies predict that the West Antarctic Ice Sheet will become increasingly unstable under warmer conditions. Insights on such change can be assisted through investigations of the subglacial landscape, which contains imprints of former ice-sheet behavior. Here, we present radio-echo sounding data and satellite imagery revealing a series of ancient large sub-parallel subglacial bed channels preserved in the region between the Möller and Foundation Ice Streams, West Antarctica. We suggest that these newly recognized channels were formed by significant meltwater routed along the icesheet bed. The volume of water required is likely substantial and can most easily be explained by water generated at the ice surface. The Greenland Ice Sheet today exemplifies how significant seasonal surface melt can be transferred to the bed via englacial routing. For West Antarctica, the Pliocene (2.6–5.3 Ma) represents the most recent sustained period when temperatures could have been high enough to generate surface melt comparable to that of present-day Greenland. We propose, therefore, that a temperate ice sheet covered this location during Pliocene warm periods

The Relationship Between Provider Competence, Content Exposure, and Consumer Outcomes in Illness Management and Recovery Programs

Provider competence may affect the impact of a practice. The current study examined this relationship in sixty-three providers engaging in Illness Management and Recovery with 236 consumers. Improving upon previous research, the present study utilized a psychometrically validated competence measure in the ratings of multiple Illness Management and Recovery sessions from community providers, and mapped outcomes onto the theory underlying the practice. Provider competence was positively associated with illness self-management and adaptive coping. Results also indicated baseline self-management skills and working alliance may affect the relationship between competence and outcomes

Illness management and recovery in community practice

Objective To examine provider competence in providing Illness Management and Recovery (IMR), an evidence-based self-management program for people with severe mental illness, and the association between implementation supports and IMR competence. Methods IMR session recordings, provided by 43 providers/provider pairs, were analyzed for IMR competence using the IMR treatment integrity scale. Providers also reported on receipt of commonly available implementation supports (e.g., training, consultation). Results Average IMR competence scores were in the “Needs Improvement” range. Clinicians demonstrated low competence in several IMR elements: significant other involvement, weekly action planning, action plan follow-up, cognitive-behavioral techniques, and behavioral tailoring for medication management. These elements were commonly absent from IMR sessions. Competence in motivational enhancement strategies and cognitive-behavioral techniques differed based on the module topic covered in a session. Generally, receipt of implementation supports was not associated with increased competence; however, motivational interviewing training was associated with increased competence in action planning and review. Conclusions and Implications for Practice IMR, as implemented in the community, may lack adequate competence and commonly available implementation supports do not appear to be adequate. Additional implementation supports that target clinician growth areas are needed

Leader-Member Exchange across two hierarchical levels of leadership: concurrent influences on work characteristics and employee psychological health.

Leader-Member Exchange (LMX) theory suggests that the quality of the leader–employee relationship is linked to employee psychological health. Leaders who reside at different hierarchical levels have unique roles and spheres of influence and potentially affect employees' work experiences in different ways. Nevertheless, research on the impact of leadership on employee psychological health has largely viewed leaders as a homogeneous group. Expanding on LMX theory, we argue that (1) LMX sourced at the levels of the line manager (LM) and senior management (SM) team will be differentially linked to employee psychological health (assessed as worn-out) and that (2) these relationships will be mediated by perceived work characteristics (reward and recognition, workload management, quality of relationships with colleagues and physical environment). Structural equation modelling on data from 337 manual workers partially supported the hypotheses. Perceptions of the physical environment mediated the relationship between LMX at the LM level and employee psychological health, whereas perceptions of workload management mediated the relationship between LMX at the SM level and psychological health. These findings corroborate arguments that leaders are not a uniform group and as such the effects of LMX on employees will depend on leadership hierarchy. Implications for expanding leadership theory are discussed

A Model-Based Analysis of Chemical and Temporal Patterns of Cuticular Hydrocarbons in Male Drosophila melanogaster

Drosophila Cuticular Hydrocarbons (CH) influence courtship behaviour, mating, aggregation, oviposition, and resistance to desiccation. We measured levels of 24 different CH compounds of individual male D. melanogaster hourly under a variety of environmental (LD/DD) conditions. Using a model-based analysis of CH variation, we developed an improved normalization method for CH data, and show that CH compounds have reproducible cyclic within-day temporal patterns of expression which differ between LD and DD conditions. Multivariate clustering of expression patterns identified 5 clusters of co-expressed compounds with common chemical characteristics. Turnover rate estimates suggest CH production may be a significant metabolic cost. Male cuticular hydrocarbon expression is a dynamic trait influenced by light and time of day; since abundant hydrocarbons affect male sexual behavior, males may present different pheromonal profiles at different times and under different conditions

High incidence of Noonan syndrome features including short stature and pulmonic stenosis in patients carrying NF1 missense mutations affecting p.Arg1809: genotype-phenotype correlation

Neurofibromatosis type 1 (NF1) is one of the most frequent genetic disorders, affecting 1:3,000 worldwide. Identification of genotype-phenotype correlations is challenging because of the wide range clinical variability, the progressive nature of the disorder, and extreme diversity of the mutational spectrum. We report 136 individuals with a distinct phenotype carrying one of five different NF1 missense mutations affecting p.Arg1809. Patients presented with multiple cafe-au-lait macules (CALM) with or without freckling and Lisch nodules, but no externally visible plexiform neurofibromas or clear cutaneous neurofibromas were found. About 25% of the individuals had Noonan-like features. Pulmonic stenosis and short stature were significantly more prevalent compared with classic cohorts (P<0.0001). Developmental delays and/or learning disabilities were reported in over 50% of patients. Melanocytes cultured from a CALM in a segmental NF1-patient showed two different somatic NF1 mutations, p.Arg1809Cys and a multi-exon deletion, providing genetic evidence that p.Arg1809Cys is a loss-of-function mutation in the melanocytes and causes a pigmentary phenotype. Constitutional missense mutations at p.Arg1809 affect 1.23% of unrelated NF1 probands in the UAB cohort, therefore this specific NF1 genotype-phenotype correlation will affect counseling and management of a significant number of patients

Rheumatoid arthritis - clinical aspects: 134. Predictors of Joint Damage in South Africans with Rheumatoid Arthritis

Background: Rheumatoid arthritis (RA) causes progressive joint damage and functional disability. Studies on factors affecting joint damage as clinical outcome are lacking in Africa. The aim of the present study was to identify predictors of joint damage in adult South Africans with established RA. Methods: A cross-sectional study of 100 black patients with RA of >5 years were assessed for joint damage using a validated clinical method, the RA articular damage (RAAD) score. Potential predictors of joint damage that were documented included socio-demographics, smoking, body mass index (BMI), disease duration, delay in disease modifying antirheumatic drug (DMARD) initiation, global disease activity as measured by the disease activity score (DAS28), erythrocyte sedimentation rate (ESR), C reactive protein (CRP), and autoantibody status. The predictive value of variables was assessed by univariate and stepwise multivariate regression analyses. A p value <0.05 was considered significant. Results: The mean (SD) age was 56 (9.8) years, disease duration 17.5 (8.5) years, educational level 7.5 (3.5) years and DMARD lag was 9 (8.8) years. Female to male ratio was 10:1. The mean (SD) DAS28 was 4.9 (1.5) and total RAAD score was 28.3 (12.8). The mean (SD) BMI was 27.2 kg/m2 (6.2) and 93% of patients were rheumatoid factor (RF) positive. More than 90% of patients received between 2 to 3 DMARDs. Significant univariate predictors of a poor RAAD score were increasing age (p = 0.001), lower education level (p = 0.019), longer disease duration (p < 0.001), longer DMARD lag (p = 0.014), lower BMI (p = 0.025), high RF titre (p < 0.001) and high ESR (p = 0.008). The multivariate regression analysis showed that the only independent significant predictors of a higher mean RAAD score were older age at disease onset (p = 0.04), disease duration (p < 0.001) and RF titre (p < 0.001). There was also a negative association between BMI and the mean total RAAD score (p = 0.049). Conclusions: Patients with longstanding established RA have more severe irreversible joint damage as measured by the clinical RAAD score, contrary to other studies in Africa. This is largely reflected by a delay in the initiation of early effective treatment. Independent of disease duration, older age at disease onset and a higher RF titre are strongly associated with more joint damage. The inverse association between BMI and articular damage in RA has been observed in several studies using radiographic damage scores. The mechanisms underlying this paradoxical association are still widely unknown but adipokines have recently been suggested to play a role. Disclosure statement: C.I. has received a research grant from the Connective Tissue Diseases Research Fund, University of the Witwatersrand. All other authors have declared no conflicts of interes