Bermuda has one of the highest concentrations of cave systems of any country in the world, but as the resident human population and tourism expand, this unique habitat is becoming increasingly threatened by development and water pollution. A water quality assessment was performed in six of Bermuda’s anchialine cave pools during summer 2007. Vertical water profiles were collected at each site to determine temperature, salinity, dissolved oxygen, and pH levels throughout the water column. Each cave pool had its own unique hydrological patterns. Additionally, water samples were collected at the surface and at the maximum depth to determine the concentration of nitrate, nitrite, ammonium, phosphate, and urea in the water. Further samples were collected to establish the fecal bacteria content in the surface waters. High nitrate levels were measured in two of the cave pools, while unsafe bacterial levels were measured in three pools. In situ nutrient addition experiments were used to examine effects of nutrient enrichment on algae naturally occurring in the six cave pool. Initial assessments of the pools determined distribution of foliose species. Six algal species (Ulva sp., Caulerpa mexicana, C. racemosa, C. sertularioides, Halymenia floresii, and Cryptonemia sp.) inhabited multiple sites, but not all species occurred at all sites. Changes in the biomass of individual plants were recorded for 6 to 12 days in response to N (nitrate), P (phosphate), and NP additions. The effect of nutrient addition on increase in biomass was significant over a 6 day period for Ulva sp. and H. floresii. Intermediate to no growth was seen in C. mexicana and Cryptonemia sp. C. mexicana exhibited both increases and in biomass depending on the site. Cryptonemia sp. had low but positive growth. A significant decrease in biomass occurred with C. racemosa and C. sertularioides. Primary productivity was measured using the traditional light dark bottle method. Differences in net productivity and respiration may explain why some plants responded positively and other negatively to nutrient additions. Ulva sp. and H. floresii showed potential as bioindicators for groundwater quality.

Benthic microalgae (BMA) living within the surface sediment of salt marshes are highly productive organisms that provide a significant proportion of organic carbon inputs into estuarine systems. BMA secrete extracellular carbohydrates in the form of low molecular weight carbohydrates and extracellular polymeric substances (EPS) as they migrate within the sediment. EPS plays an important role in the structure and function of BMA biofilms in shallow-water systems as EPS affects habitat structure, stabilizes the sediment, reduces sediment erosion, and is a carbon source for organisms. This study looked at the effect of nutrients and carbohydrate additions on BMA biomass, bacterial biomass, carbohydrate production, and glycosidase activity in the surface 5 mm of intertidal sediment in a subtropical salt marsh (Galveston Bay, Texas). Nitrogen and phosphorus were added to cores collected from the salt marsh and incubated in the lab over four days. Very little change was seen in the biomass of the benthic microalgae or in the different carbohydrate fractions with the added nutrients. The mean chlorophyll a concentration was 13 +/- 5 ug g-1 sediment, the mean saline extractable carbohydrate concentration was 237 +/- 113 ug g-1 sediment, and the mean EPS concentration was 48 +/- 25 ug g-1 sediment. The chlorophyll a and saline extractable carbohydrate concentrations initially decreased over the first 24 hours, but then increased over the rest of the experiment, indicating a possible species compositional shift in the BMA. With no major response with nutrient additions, it is likely that a different environmental factor is limiting for the growth of the benthic microalgae, and therefore the production of sEPS, in this salt marsh. A series of experiments was conducted in situ by adding glucose, alginic acid, and phosphorus to sediment within experimental plots. Samples were taken periodically over three to seven days to determine the biomass of the microbial community, enzyme activities and kinetics, and changes in the concentrations of several sediment carbohydrate pools. u-glucosidase activities (15 +/- 3 nmol g-1 h-1) were significantly higher than u-xylosidase (6 +/- 2 nmol g-1 h-1) and u-galactosidase (8 +/- 2 nmol g-1 h-1) activities within the sediment, and there was no suppression of u-glucosidase activity measured with the glucose addition. These data represent the first measurement of u- xylosidase and u-galactosidase activity in intertidal sediment dominated by BMA. Although preliminary experiments suggested a possible phosphorus limitation within the sediment, there was little change in the bacteria abundance or the benthic microalgae biomass when phosphorus was added in situ. This study begins to illustrate the dynamics of carbohydrate production and loss in this salt marsh, and the ability for the microbial community in the salt marshes of Galveston Bay to adjust to the nutrient and carbohydrate treatments.

Thesis (Ph. D.)--Florida State University, 2002. / Advisor: Dr. Tom Anderson, Florida State University, School of Visual Arts and Dance, Dept. of Art Education. Title and description from dissertation home page (viewed Oct. 7, 2003). Includes bibliographical references.

The aim of the research was to evaluate the premarital enrichment programme designed by Pretorius (1997) for couples who wish to remarry. The study was motivated by literature, which shows a high likelihood of divorce among divorcees who remarry. Three interested couples responded to advertisements placed in a local Potchefstroom newspaper and announcements made in churches. A qualitative (case study method) research design was used. The programme consisted of six two-hour sessions. The programme was conducted over two weekends. The first three sessions were held with all three couples and the last three sessions with each couple separately due to conflicting schedules. The effect of the programme was assessed by five measuring instruments, participants' metaphoric drawings of their relationships, semi-structured interviews, and the researcher's observations of the interaction between the participants. The assessment took place a week before and four weeks after the programme presentation. The results obtained indicated that two of the couples experienced changes whilst the other couple experienced minimal change. The change that occurred in the two couples were with regards to their communication and conflict management, their implementation of boundaries, intimacy, security in their relationship, growth, and dyadic adjustment. It was concluded that the premarital enrichment programme prepared two couples for remarriage, specifically with regards to their adjustment in the relationship. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2005.

Autism, a neurodevelopmental disorder, is assumed to result from early neural tube damage. Individuals with Autism exhibit macroencephaly during childhood. To examine increased neurogenesis as a factor in macroencephaly, the valproic acid (VPA) model of Autism was used to examine how exposure to enrichment affects neurogenesis in the dentate gyrus. To induce the model, pregnant rats received two 100mg/kg VPA injections on days 11, 12, and 13 of gestation. Half the pups in each group were exposed to enrichment from post-natal days 30-60. Neurogenesis was examined by fluorescence microscopy for the proliferation marker bromodeoxyuridine (BrdU) and neuronal specific nuclear marker (NeuN). Counts of double-labeled cells were done from the dentate gyrus, an area known for adult neurogenesis. Results indicate that neurogenesis is not abnormal in the VPA model and enrichment increases the neurogenesis similarly in both VPA and control animals. This research provides a better understanding of brain plasticity in the VPA model of Autism.

No description available.

The aim of the research was to evaluate the premarital enrichment programme designed by Pretorius (1997) for couples who wish to remarry. The study was motivated by literature, which shows a high likelihood of divorce among divorcees who remarry. Three interested couples responded to advertisements placed in a local Potchefstroom newspaper and announcements made in churches. A qualitative (case study method) research design was used. The programme consisted of six two-hour sessions. The programme was conducted over two weekends. The first three sessions were held with all three couples and the last three sessions with each couple separately due to conflicting schedules. The effect of the programme was assessed by five measuring instruments, participants' metaphoric drawings of their relationships, semi-structured interviews, and the researcher's observations of the interaction between the participants. The assessment took place a week before and four weeks after the programme presentation. The results obtained indicated that two of the couples experienced changes whilst the other couple experienced minimal change. The change that occurred in the two couples were with regards to their communication and conflict management, their implementation of boundaries, intimacy, security in their relationship, growth, and dyadic adjustment. It was concluded that the premarital enrichment programme prepared two couples for remarriage, specifically with regards to their adjustment in the relationship. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2005.

Autism, a neurodevelopmental disorder, is assumed to result from early neural tube damage. Individuals with Autism exhibit macroencephaly during childhood. To examine increased neurogenesis as a factor in macroencephaly, the valproic acid (VPA) model of Autism was used to examine how exposure to enrichment affects neurogenesis in the dentate gyrus. To induce the model, pregnant rats received two 100mg/kg VPA injections on days 11, 12, and 13 of gestation. Half the pups in each group were exposed to enrichment from post-natal days 30-60. Neurogenesis was examined by fluorescence microscopy for the proliferation marker bromodeoxyuridine (BrdU) and neuronal specific nuclear marker (NeuN). Counts of double-labeled cells were done from the dentate gyrus, an area known for adult neurogenesis. Results indicate that neurogenesis is not abnormal in the VPA model and enrichment increases the neurogenesis similarly in both VPA and control animals. This research provides a better understanding of brain plasticity in the VPA model of Autism.

<p>The interactions between the brain and the immune system are extensive and each has a profound influence on the other. The hippocampus is a brain region that is strongly impacted by the immune system, especially considering its large population of microglia, the resident immune cells of the brain. Cytokines and chemokines, the signaling molecules from immune cells, signal within the central nervous system (CNS) as well, and they are critical in hippocampal function. The relationship between the immune system and the hippocampus may underlie its particular vulnerability to diseases and disorders of the nervous system and the periphery. Conversely, immune signaling within the hippocampus is affected by alterations in hippocampal resilience and flexibility, such that increased hippocampal plasticity reduces vulnerability to immune challenges. The balance between risk and resilience in the hippocampus is modulated by immune signaling, especially by microglia.</p><p> The hippocampus is vulnerable to immune challenges, disease and injury, but it is simultaneously a region capable of profound plasticity and flexibility. The following dissertation experiments were designed to assess the roles of microglia and their signaling molecules, cytokines and chemokines, during normal hippocampal processes, such as learning and memory and response to immune challenge. The first set of experiments examined the effects of a neonatal bacterial infection in rats on hippocampal-dependent learning and memory as well as neuronal and microglial signaling in adulthood. In the first experiment, neonatally infected rats have impaired memory during fear conditioning following an immune challenge in adulthood. The impairment is caused by the exaggerated expression of the pro-inflammatory cytokine, interleukin (IL)-1&#946;, within the hippocampus during learning. Hippocampal microglia are the primary source of IL-1&#946; and the microglia in neonatally infected rats are "primed" by the infection into adulthood. In the second experiment, neonatally infected rats are more accurate on a Morris Water maze task following minimal training in adulthood, but have significantly impaired memory for a reversal platform location. In addition to improved accuracy, they have lower neural activation as measured by Arc protein expression within the dentate gyrus (DG) of the hippocampus. The next set of experiments assessed the effects of increasing hippocampal plasticity on immune signaling within the hippocampus. Following 7 weeks of environmental enrichment (EE), enriched rats had an attenuated pro-inflammatory response within the hippocampus in response to an in vivo peripheral immune challenge. The reduced immune response was specific to a subset of cytokines and chemokines and occurred only within the hippocampus and not adjacent cortical regions. Enrichment increased glial antigen expression within the DG as well. In another group of enriched rats, an ex vivo stimulation of isolated hippocampal microglia from EE rats demonstrated that the reduced microglial reactivity observed in vivo requires influence of other neural cell types on microglia phenotype, such that microglia within the DG of EE rats are smaller than controls. Taken together, these experiments define cellular and molecular mechanisms of hippocampal vulnerability and resilience as a function of interactions between the brain and the immune system.</p> / Dissertation

Thesis (doctoral)--Philipps-Universitẗ zu Marburg.