Recruitment and mortality of Rhizophora mangle L. seedlings in the Tropical Southwestern Atlantic mangrove.

Studies in the long-term recruitment and mortality of mangrove seedlings can help to understand mangrove demography and its relationship with climatic variables, environmental restoration and advances in the ecology of this ecosystem. A seven-year population dynamics study of seedling recruitment and mortality in cohorts of Rhizophora mangle L. was carried out to identify expansion processes and patterns of survival in the understory of mangrove forests on the Atlantic coast of Brazil. The present study aimed to evaluate the relationship between recruitment and mortality R. mangle seedlings at the population level, salinity, and climatic variables (precipitation, temperature and humidity). On an annual scale, seedling recruitment was positively correlated with mean temperature. Seedling density was negatively correlated with the number of recruits and positively with the number of deaths. The number of recruits was associated with dead seedlings, temperature and precipitation considering a population scale, without grouping the data. The seedling density in the stands increased with the number of dead seedlings. Our findings described the relationship between climate variability (durability and magnitude of the dry/rainy season) and the long-term population dynamics of R. mangle seedlings in a poorly studied region and from what moment, on a monthly and annual time scale, did this relationship become significant and changes occur. The findings of this study provide information on the population dynamics of the species that will help in understanding mangrove demography. These results have important implications for projections about the recruitment and survival of the species thinking about to long-term climate change that will modify current weather patterns and mangrove conservation efforts.

In Vitro Effect of Innovative Desensitizing Agents on Dentin Tubule Occlusion and Erosive Wear.

PURPOSE:: The purpose of this study was to evaluate the effects of four in-office desensitizing products on dentin tubule occlusion and erosive wear. METHODS:: Dentin hypersensitivity was simulated by EDTA application for five minutes. The specimens were randomly allocated into five groups (n=11), according to treatment: No treatment - Control (C), Duraphat (DUR), Desensibilize Nano P (NP), ClinPro XT Varnish (XTV), and ClinPro White Varnish (CWV). They were then submitted to erosive/abrasive cycling for five days. After EDTA, treatment, and cycling, the specimens were analyzed with an environmental scanning electron microscope (ESEM) to verify the number of opened dentin tubules (ODT) which were counted by using ImageJ software, and with a profilometer to determine the surface curvature/loss. ESEM data were analyzed with two-way repeated measure analysis of variance and Tukey tests. For the profilometer, data were analyzed with Kruskal-Wallis, Tukey, and Mann-Whitney tests. RESULTS:: After treatment, all groups showed lower ODT than the control, without significant differences between them. After cycling, the only group that showed lower ODT than the control was group XTV; however, it did not significantly differ from the other groups. For the profilometric analysis, there were significant differences in SL between the experimental times after treatment and after cycling for all groups ( p<0.05). After cycling, no surface loss was detected in groups DUR and XTV, which presented a significantly different curvature than group NP and the control group, but not from group CWV. Surface loss was detected for the control and groups NP and CWV, without difference among them. CONCLUSION:: All desensitizing agents tested presented promising results concerning the obliteration of dentin tubules immediately after treatment. XTV was the only desensitizer capable of preventing the reopening of the tubules after the erosive/abrasive challenges. XTV and DUR presented a protective effect against dentin erosive wear.

Monitoring of bedridden patients: development of a fall detection tool.

Falls of patients are an important issue in hospitals nowadays; it causes severe injuries, increases hospitalization time and treatment costs. The detection of a fall, in time, provides faster rescue to the patient, preventing more serious injuries, as well as saving nursing time. The MovinSense® is an electronic device designed for monitoring patients to prevent pressure sores, and the main goal of this work was to develop a new tool for this device, with the purpose of detecting if the patient has fallen from the hospital bed, without changing any of the device's original features. Experiments for gathering data samples of inertial signals of falling from the bed were obtained using the device. For fall detection a sensitivity of 72% and specificity of 100% were reached. Another algorithm was developed to detect if the patient got out of his/her bed.

Sewage outfall plume dispersion observations with an autonomous underwater vehicle.

This work represents one of the first successful applications of Autonomous Underwater Vehicles (AUVs) for interdisciplinary coastal research. A monitoring mission to study the shape and estimate the initial dilution of the S. Jacinto sewage outfall plume using an AUV was performed on July 2002. An efficient sampling strategy enabling greater improvements in spatial and temporal range of detection demonstrated that the sewage effluent plume can be clearly traced using naturally occurring tracers in the wastewater. The outfall plume was found at the surface highly influenced by the weak stratification and low currents. Dilution varying with distance downstream was estimated from the plume rise over the outfall diffuser until a nearly constant value of 130:1, 60 m from the diffuser, indicating the near field end. Our results demonstrate that AUVs can provide high-quality measurements of physical properties of effluent plumes in a very effective manner and valuable considerations about the initial mixing processes under real oceanic conditions can be further investigated.

Regulation of the pituitary somatotroph cell by GHRH and its receptor.

Hormones from the hypothalamus mediate interactions between the nervous and endocrine systems by controlling the activity of specific target cells in the anterior pituitary gland. The hypothalamic peptide, growth hormone-releasing hormone (GHRH), acts on pituitary somatotroph cells to stimulate their proliferation during development and to regulate their ability to produce and secrete growth hormone (GH). These actions are mediated by a recently identified receptor for GHRH that belongs to family B-III of the G protein-coupled receptor superfamily. The rat GHRH receptor is expressed predominantly in the pituitary gland and in somatotroph cells. To investigate this tissue- and cell-specific expression, the receptor gene has been cloned and characterized. The receptor gene promoter is selectively expressed in pituitary cells and is regulated by the pituitary-specific transcription factor Pit-1. There is a sexual dimorphism in GHRH receptor expression in the rat pituitary, suggesting regulation by gonadal steroids. In addition, glucocorticoids are potent positive regulators of GHRH receptor gene expression. Substantial evidence points to an important role for GHRH in regulating the proliferation and functional activity of the somatotroph cell. This is best observed in the dwarf little mouse, which harbors a mutation in the extracellular domain of the GHRH receptor that abolishes the receptor's hormone-binding and signaling properties, resulting in severe somatotroph hypoplasia. Complementary studies in transgenic mice overexpressing the ligand GHRH reveal corresponding somatotroph hyperplasia. Consistent with these observations, GHRH potently activates the MAP kinase pathway in pituitary somatotroph cells. To better understand the hormone-binding and signaling properties of the GHRH receptor, mutant and chimeric receptors have been analyzed to define domains important for GHRH interaction. The GHRH receptor signals predominantly through cAMP-dependent pathways; however, a variant form of the GHRH receptor with an insertion into the third intracellular domain, generated through alternative RNA processing, binds GHRH but fails to signal, suggesting potential modulation of receptor function at a post-transcriptional level. This chapter will integrate these basic investigations of GHRH and its receptor with current information on the involvement of the GHRH signaling system in human diseases of GH secretion and growth.