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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Exceptionally well-preserved quaternary fossils from Sawmill Sink blue hole, Abaco, The Bahamas

Albury, Nancy Ann 01 May 2010 (has links)
A diverse assemblage of exquisitely-preserved fossil animals and plants were collected from Sawmill Sink blue hole in Abaco, Bahamas. More than 40 species have been identified including extinct tortoise, an extant crocodile, and birds that no longer live in The Bahamas. This study addresses the mechanisms that preserve fossils in blue holes and discusses paleoecological implications from faunal diversity and sediment composition. Blue holes are waterilled caves with surface openings that may trap animals and surface-driven vegetation. In Sawmill Sink the talus cone within the halocline acts as a substrate on which organics collect that drive microbe ecology. Their byproducts, hydrogen sulfide and anoxia, inhibit biological destruction and delay necrolysis. Low tidal flow and quiescent water conditions further enhance stability of the depositional environment. In addition, subaerial conditions during glacial lowstands allowed owls to roost; their deposits formed a rich assemblage of small fossil vertebrates.
2

Dispepsia funcional en estudiantes de ocho facultades de medicina peruanas. Influencia de los hábitos

Vargas, Mariela, Talledo Ulfe, Lincolth, Samaniego, Reimer O., Heredia, Paula, Rodríguez, Christian A S., Mogollón, César A., Enriquez, Walter F., Mejia, Christian R. 06 1900 (has links)
Functional dyspepsia impacts on quality of life. Due to its multifactorial etiology its characterization proves difficult, especially in populations at risk such as medical students. Objetives. To determine if behavioral and harmful habits of medical students from eight universities of Peru were associated to functional dyspepsia. Methods. Multicentric, cross-sectional study. A self-administered questionnaire was taken among students enrolled in eight medical faculties in Peru. Functional dyspepsia was measured using a validated test; diet characteristics, alcohol, tobacco, coffee or energy drinks consumption were considered behavioral habits. Furthermore, others from the social and educational sphere were measured. Bivariate and multivariate statistical analyses were made. Results. From a total of 1.923 students, the median of the ages was 20, 55% were women and 24% suffered from functional dyspepsia. Factors which diminished the frequency of functional dyspepsia were masculine gender (aPR:0,75; 95%CI:0.64-0.87; p < 0,001), hours spent studying (aPR:0,97; 95%CI:0,96-0,99; p < 0,001) and eating following a fixed schedule (aPR:0,80; 95%CI:0,67- 0,95; p = 0,013); however, having failed a course increases the frequency of functional dyspepsia (aPR:1.24; 95%CI:1.13-1.37; p < 0,001)adjusted for age, as well as difficulties to fall asleep and depression. Conclusion. Many medical students suffered from functional dyspepsia, this being related to several behavioral variables; therefore further studies as well as educational institutions’ intervention is required, due to the short and long term problems that may arise from this situation. / Revisión por pares
3

The Caves, Karst, and Geology of Abaco Island, Bahamas

Walker, Lindsay N 13 May 2006 (has links)
Abaco Island is located on Little Bahama Bank at the northwestern extent of the Bahamian Archipelago. Karst features on Abaco include: flank margin caves, karren, blue holes, pit caves, banana holes, and cone karst. As part of this study all known flank margin caves on Abaco were GPS located and surveyed. The presence and locations of the other karst features were recorded as part of the karst inventory of Abaco. The cone karst is of particular interest because cone karst has not been documented on other Bahamian islands. These cones form from the dissection of an eolianite ridge due to karst, fire, and vegetative processes. Tafoni-like recesses, originally believed to be high flank margin caves, were formed during cliffing of an eolianite ridge during the OIS 5e highstand. The geologic evolution of representative depositional sequences on Abaco fits within the accepted Bahamian stratigraphy.
4

A Vegetation History from Emerald Pond, Great Abaco Island, The Bahamas, Based on Pollen Analysis

Slayton, Ian Arthur 01 August 2010 (has links)
Emerald Pond (26° 32' 12" N, 77° 06' 32" W) is a vertical-walled solution hole in the pine rocklands of Great Abaco Island, The Bahamas. In 2006, Sally Horn, Ken Orvis, and students recovered an 8.7 m-long sediment core from the center of the pond using a Colinvaux-Vohnout locking piston corer. AMS radiocarbon dates on macrofossils are in stratigraphic order and indicate that the sequence extends to ca. 8400 cal yr BP. Basal deposits consist of aeolian sands topped by a soil and then pond sediment, suggesting that the site began as a sheltered, dry hole during a Late Pleistocene low sea level stand, and became moister as climate changed and rising sea level pushed up the freshwater table. The limestone rockland surrounding the site is presently dominated by Bahamian pine (Pinus caribaea Morelet var. bahamensis (Griseb.) W.H. Barrett & Golfari) with an understory of hardwoods and several palm species. Pollen analyses on the sediments of Emerald Pond indicate significant environmental change at the site. Pines and palms have dominated for much of the record, with some variation in relative importance. Pine pollen shows a non-uniform, general increase over the record, with highest values reached in a section of the upper meter of the record that contains abundant microscopic charcoal that may be related to anthropogenic activities. Palm pollen is well represented in all but this upper section of the core. The shifts in pollen percentages in the upper meter of the core suggest a generally drier environment during the last two millennia at Emerald Pond.

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