Boynton Beach City Library Local History Archives

The mission of the Boynton Beach City Library Local History Archives is to collect, preserve, and make accessible the heritage of the people of our region. Our holdings include physical and digital collections of manuscripts, maps, books, scrapbooks, postcards, photographs, records, and ephemera. We welcome all members of the Boynton Beach communities and the general public

Procedimento obstétrico no parto e mortalidade nas regiões do Brasil no ano de 2002

Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Departamento de Saúde Pública

Interactions between mantle plumes and mid-ocean ridges : constraints from geophysics, geochemistry, and geodynamical modeling

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2001This thesis studies interactions between mid-ocean ridges and mantle plumes using geophysics, geochemistry, and geodynamical modeling. Chapter 1 investigates the effects of the Marion and Bouvet hotspots on the ultra-slow spreading, highly-segmented Southwest Indian Ridge (SWIR). Gravity data indicate that both Marion and Bouvet impart high-amplitude mantle Bouguer anomaly lows to the ridge axis, and suggest that long-offset transforms may diminish along-axis plume flow. Building upon this observation, Chapter 2 presents a series of 3D numerical models designed to quantify the sensitivity of along-axis plume-driven mantle flow to transform offset length, spreading rate, and mantle viscosity structure. The calculations illustrate that long-offset transforms in ultra-slow spreading environments may significantly curtail plume dispersion. Chapter 3 investigates helium isotope systematics along the western SWIR as well as near a global array of hotspots. The first part of this study reports uniformly low 3HetHe ratios of 6.3-7.3 RlRa along the SWIR from 9°-24°E, compared to values of 8±1 Ra for normal mid-ocean ridge basalt. The favored explanation for these low values is addition of (U+ Th) into the mantle source by crustal and/or lithospheric recycling. Although high HetHe values have been observed along the SWIR near Bouvet Island to the west, there is no evidence for elevated 3HetHe ratios along this section of the SWIR. The second part of Chapter 3 investigates the relationship between 3HetHe ratios and geophysical indicators of plume robustness for nine hotspots. A close correlation between a plume's flux and maximum 3HetHe ratio suggests a link between plume upwelling strength and origination in the deep, relatively undegassed mantle. Chapter 4 studies 3D mantle flow and temperature patterns beneath oceanic ridge-ridge-ridge triple junctions (TJs). In non-hotspot- affected TJs with geometry similar to the Rodrigues TJ, temperature and upwelling velocity along the slowest-spreading of the three ridges are predicted to increase within a few hundred kilometers of the TJ, to approach those of the fastest-spreading ridge. Along the slowest-spreading branch in hotspot-affected TJs such as the Azores, a strong component of along-axis flow directed away from the TJ is predicted to advect a hotspot thermal anomaly away from its deep-seated source.Funding was provided by the National Science Foundation through grants OCE- 9811924 and OCE-9907630, and by a National Defense Science and Engineering Graduate Fellowship

Lithospheric Control on the Spatial Pattern of Azores Hotspot Seafloor Anomalies: Constraints from a Model of Plume-Triple Junction Interaction

The Azores hotspot is located near a plate boundary triple junction (TJ) consisting of the Terceira Rift (TER) and two branches of the Mid-Atlantic Ridge (MAR). The seafloor expression of the Azores hotspot has a complex spatial pattern. Latitudinal anomalies in seafloor depth and other data along the MAR extend farther to the south of the inferred location of the mantle heterogeneity than to the north. Longitudinal anomalies span a greater distance to the east of the MAR (along the TER) than to the west. A finite element model is used to investigate how the divergence of three plates away from a TJ may affect the spatial dispersion of thermally buoyant material simulating a mantle plume. Prescribed plate motion vectors approximate the kinematics of the Azores TJ during a main phase of plateau formation similar to ∼7 Ma. The plume is located off axis to the southeast of the simulated triple junction, following several studies that suggest that the present-day conduit is located near the islands of Faial and Pico. Asymmetry in the divergence of the three plates with respect to the triple junction tends to drive plume material preferentially southward and eastward, consistent with observed anomalies

Due diligence applied

Illustration not included in Web versio

Management behavior -- An auditing horizon

https://egrove.olemiss.edu/dl_proceedings/1182/thumbnail.jp

Plate Boundary and Triple Junction Control of Shatsky Rise Formation and Implications for Other Ocean Plateaus

In the study of marine large igneous provinces, investigations often focus on the importance of mantle plumes in generating excess magmatism. Few studies, however, have addressed the role of plate boundary processes in promoting widespread and extensive mantle melting. This study investigates how spreading center geometry may have facilitated the emplacement of Shatsky Rise, an oceanic plateau in the western Pacific Ocean. The largest structure within Shatsky Rise, Tamu Massif, was created ∼140–150 Ma at the Pacific-Izanagi-Farallon (PIF) ridge-ridge-ridge triple junction. Moreover, the PIF triple junction was one of three triple junctions operating in close proximity at the time, as the nascent Pacific Plate (NPP) began to expand in size. This study suggests that the thermal conditions of the NPP, which likely resulted in a large area of thin lithosphere, could have significantly facilitated widespread mantle melting as well as the magmatic expression of any nearby mantle plume

The Relationship Between Task Performance in Diadochokinetic Rate and Speech Naturalness in Cerebellar Ataxia

The purpose of this study was to determine the relationship between the perceptual measure of speech naturalness and the objective measure of diadochokinetic rates (DDK) in individuals with ataxic dysarthria. Cerebellar ataxia results from disruption in cerebellar motor control and coordination. We hypothesized that the articulatory coordination task, DDK, would be strongly related to the perception of speech naturalness because of the coordinator deficits that contribute to both. Twenty-seven individuals with ataxia and 28 sex- and age-matched controls produced the DDK task. Syllable duration and rate of syllable production was assessed and compared with perceptual measures of speech naturalness and only the ataxia group did the speech naturalness task. This task involved describing pictures and reading passages and the speakers were rated on a scale of 1-7, 1 meaning their speech sounded highly unnatural and 7 meaning that their speech sounded highly natural. We found that syllable duration was significantly longer and syllable rate was consistently slower in the ataxia group. Furthermore, speech naturalness was highly correlated with both syllable duration and syllable rate. Speakers who spoke longer syllables and spoke at a slower rate were perceived as less natural than those who spoke shorter syllables at a faster rate. This study confirms that articulatory coordination in the DDK task is highly reflective of perceived speech naturalness in ataxic dysarthria and can be used clinically to support perceptual observations.</p