No description available.

The addition of buried impact structures to the known database of surface structures is key to a complete understanding of the geologic history of Mars because it allows for a more precise calculation of crustal age. Also, because these buried structures record an impact event and a resurfacing event they can be used to clearly define crustal versus surface ages. This study used topographic data and a crustal thickness model to identify buried and visible impact structures. This process was repeated twice and then correlated to create a global database of impact structures greater than 200 km. During the study confidence factor protocol was developed based on [1] ratio of crater diameter to relief and [2] percentage of rim present. This criteria was applied to each visible and buried structure. The comparison of visible and buried impact structures provides constraints on the timing of resurfacing events. Cumulative and N(300) values were calculated to derive the relative crustal ages in major geologic provinces. It was found that [1] the Martian lowlands and highlands have similar crustal ages when combining the visible and buried impact structures, [2] Tharsis is younger than these two regions, [3] the lowlands appear to have been thinned before or during the Late Heavy Bombardment (LBH), and [4] the resurfacing of the lowlands must have happened at the same time or shortly after the rise of the Tharsis bulge. / Geology

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Bibliography: leaves 26-27. / M.S.

Deformation in southern Alaska is controlled by the accretion and partial subduction of the Yakutat terrane as margin-parallel motion transitions to subduction. Recent studies have shown that deformation in the St. Elias orogen, at the northern end of the terrane, accommodates a large portion of convergence, but deformation at the eastern and southern margins remains more poorly constrained. Rapid recent sedimentation (> 1cm/yr) and glacio-isostatic uplift rates (> 3 cm/yr) in the Fairweather corridor highlight short-term vertical deformation at the eastern margin; however, the relationship between these rates and long-term deformation is less well known. New low-temperature cooling ages are reported along the eastern flank of the St. Elias orogen, placing constraints on vertical deformation over the past few million years. Young cooling ages (< 3 Ma) occur in a broad zone, extending along the onshore length of the strike-slip Fairweather fault. These ages indicate that protracted convergence has been accommodated in the Fairweather corridor. Average (~1 mm/yr) and peak (~3 mm/yr) late Cenozoic exhumation rates are similar to rates to the north, and suggest that the orogen is actually boomerang-shaped in map view. If ~1 mm/yr exhumation has been steady, the onset of rapid exhumation is constrained to post-12 Ma, but likely occurred at 5 Ma with changes in climate and plate obliquity. Although cooling ages reveal no coherent regional pattern relative to known structures, they indicate the margin accommodates a significant component of pure shear and is slip-partitioned. The resolved magnitude of convergence in the Fairweather corridor also indicates that Yakutat terrane motion is rotated from Pacific plate motion, and likely requires significant slip on the Transition fault at the southern edge of the Yakutat terrane. Although million-year exhumation rates are rapid, they are slower than short-term rates related to deglaciation. / Master of Science

This qualitative study examined the experience of divorced Latter-day Saints beginning to date again after having been sealed in an LDS temple. Eight divorced Latter-day Saints participated in semi-structured interviews, with areas of inquiry covering the reason for divorce, current romantic relationships, whether participants discussed their prior sealing with new partners, challenges and benefits participants experienced in dating again, what had been helpful to them as they began dating, what they wished family and friends knew, plans for marriage, and whether they would consider non-LDS partners. Data were analyzed thematically and themes were generated by grouping similar responses. Participants over 30 expressed discouragement at the number of available partners in the LDS faith, while those under 30 felt optimism that they could re-marry. Participants also indicated difficulty transitioning back to sexual abstinence and making sense of divorce in light of their religious beliefs. However, participants also reported enjoying singlehood and the opportunities it presented, and some showed signs of personal and spiritual growth. Participants over 30 considered dating and marrying outside of their faith to not be alone, which decision brought mixed support from family members. While family and community members were generally supportive, divorced Mormons continue to report a sense of "otherness" in their community. Recommendations for clinicians in working with this population are included. / Master of Science

The influence of erosion on uplifting orogens has been demonstrated to be a primary force in landscape development. An understanding of fluvial erosion in mountain belts is fairly well documented, but the impact of glacial erosion is yet to be fully recognized. The uplift of the Chugach-St. Elias Mountains over the last 5-6 Ma under the influence of intense glaciation provides a unique setting to study the impact of glacial erosion on landscape development. The range has been built by rapid convergence (~5 cm/yr) of the Yakutat terrane with North America. Climatic forcing of northward-driven storms has created a disproportionate glacier distribution across strike, where extensive piedmont glaciers (low equilibrium line altitudes) cover the windward side of the range and small isolated glaciers (high equilibrium line altitudes) occupy the leeward side. If glacial erosion is greatest at the equilibrium line altitude, then glaciers will act as "buzzsaws" there to limit topographic development. Exhumation would therefore be expected to increase towards the coast. If glacial erosion is not dominant, exhumation would be expected to increase away from the coast towards the core of the range, where fault dip angles are high and deep crustal rocks are exposed. To determine the impact of long-term glacial erosion on exhumation of the Chugach-St. Elias Mountains, samples were collected along and across the strike of the range and analyzed by the apatite radiogenic helium (AHE) technique. Samples previously dated using the apatite fission track (AFT) method and located adjacent to our field area were also included in the analyses. The low-temperature sensitivity of these thermochronometers allows exhumation rates to be determined for shallow crustal depths. Both glacial and tectonic processes have influenced exhumation of the range. Exhumation rates increase to the south and east towards the collision zone, but coastal rates (0.36-2.5 mm/yr) are significantly higher than inland samples (0.038-0.24 mm/yr). These rates indicate that coastal glaciation plays a dominant role in landscape development and suggest that short-term erosion rates inferred from sediment yields are exaggerated. Although the exhumation rates are lower than expected, the correlation of exhumation patterns, glacier distribution, and equilibrium line altitude supports the "glacial buzzsaw hypothesis". / Master of Science

Research has found that dating violence is a predictor of marital violence; however, research has been unclear about what predicts dating violence. Past research has been inconclusive. Furthermore, very few studies focus on gender differences in risk factors. This study examines a variety of risk factors for male and female perpetrators of dating violence in college dating relationships. Eight risk factors were used in this study: witnessing parental violence, experiencing childhood violence, problems with alcohol, length of relationship, relationship satisfaction, anger management skills, partner’s use of physical aggression, and partner’s use of psychological aggression. Correlations and multiple regressions were run for each gender. The study found that for males, partner’s use of physical aggression, low anger management skills and high relationship satisfaction were the strongest variables associated with male’ s use of physical aggression against a dating partner. For the females, partner’s use of physical aggression, followed by partner’s use of psychological aggression were the most significant variables. The model in this study was a good predictor of male violence, accounting for 81% of the variance, however, it only accounted for 51% of female violence which indicates that other unknown factors are influential in female’s use of physical violence. / Master of Science

No / First presented at an August 2001 national meeting of the American Chemical Society, material in this book provides a cross-section of current research in the area of chemistry applied to archaeological questions. Examples are given of the use of analytical methods in the study of a variety of archaeological materials, and inferences that can be made based on data patterns are discussed. Emphasis is on nondestructive testing and new developments in determining an object's age and composition.

Thesis (MA (Psychology))--University of Stellenbosch, 2006. / Body image and dating relationships are two of the most important topics in the lives of the female adolescents. Yet, not much South African research has been done on either of these themes with adolescent populations and no research could be found to investigate a possible relationship between these two important aspects, both internationally and locally. Therefore, the primary aim of this study was to investigate the potential relationship between female adolescents’ body image and their romantic relationships. Specifically, the aim was to determine if a relationship existed between participants’ self-rated attractiveness and body dissatisfaction, and their relationship status and romantic relationship satisfaction. There were two secondary aims. The first was to investigate how aspects like participants’ culture, age and body size were related to their body image and the second was to determine if aspects like participants’ culture, age and body size were related to their relationship status and satisfaction with their romantic relationships. Questionnaires were distributed to Afrikaans- and English- speaking White girls, Afrikaansspeaking Coloured girls and isiXhosaspeaking girls at four urban, coeducational, secondary schools and 511 questionnaires were completed. Participants selfreported their height and weight, self-rated their facial and bodily attractiveness on a 7- point scale, and completed two measures of body dissatisfaction: the Eating Disorder Inventory (EDI) Body Dissatisfaction subscale (Garner, Olmstead, & Polivy, 1983) and the Body Cathexis Scale (BCS) (Secord & Jourard, 1953). Participants also indicated their current relationship status using five categories: has never dated anyone, not dating anyone currently, casually dating one or more people, dating one person exclusively, and engaged or planning to marry, and completed the Relationship Assessment Scale (RAS) (Hendrick, 1988), a measure of relationship satisfaction. With regard to the primary aim of the study, results show that there were significant relationships between some of the measures of body image and relationship status for the total sample. In general, it was found that the girls who were involved in exclusive relationships at the time of the study had better body image than the girls who were not. Yet, results for this relationship were different for the different cultural and body mass index groups. With regard to the relationship between body image and relationship satisfaction, the Body Cathexis Scale scores significantly predicted participants’ satisfaction with their romantic relationships. Yet both weight and culture were also found to play a role in the relationship between body image and relationship satisfaction. With regard to the secondary aims of the study, culture was found to be related to body image, body mass index, relationship status and relationship satisfaction, while age played a role in participants’ body mass index and relationship status, and body mass index was related to body image, but not to relationship status and relationship satisfaction. Therefore, participants’ culture and body mass index were significant with regard to body image and romantic relationships, but was also found to play a significant role in the relationship between these two.

The application of optically stimulated luminescence (OSL) dating to desert sand dunes has allowed accumulation histories to be used as tools to infer past environmental change. In response to issues facing the interpretation of these records, two research questions are addressed in this thesis. (i) Are dune chronologies representative of dune stratigraphies? And (ii) how can we most appropriately interpret dune chronologies as records of Quaternary environmental conditions? Five dune profiles were sampled for OSL dating at two sites in the northeastern Rub’ al Khali in the southern Arabian Peninsula. The visible stratigraphy was used to guide sampling for three of the profiles and the effectiveness of this approach is assessed. A key finding is that bounding surfaces are not always identifiable as chronological hiatuses by OSL dating, given the level of precision that can be achieved. Using hierarchical relationships visible in two-dimensional exposures is therefore not guaranteed to identify the depositional units necessary to reconstruct dune histories. Comparison of the depositional records from three sampled profiles shows that there is significant variability in chronologies at both the dune and dunefield scales. In light of these findings, the use of ‘range-finder’ OSL dating was investigated as a method of increasing sample throughput in the laboratory. It is concluded that the use of partially prepared samples and shortened measurement techniques can be used to rapidly assess the chronological context of samples and target those units most useful in constructing dune profiles. A new method of presenting dunefield OSL datasets as net accumulation rates, incorporating accumulation thickness rather than relying on the frequency of ages, is presented. Within the last 30 ka, regional accumulation and preservation occurred at ~30-26, 22.5-18, 16-9, 6-2.7, 2.1-1.6, 1.1 and 0.7 ka. In conjunction with numerical model results and a review of other palaeoenvironmental archives, the regional aeolian record is interpreted as a response to changing forcing factors. High rates of net accumulation between ~16-9 ka are attributed to coeval increases in sediment supply and transport capacity. A hiatus in accumulation between ~9-6 ka is interpreted as a result of reduced sediment availability due to high moisture levels. The importance of both external forcing factors and local controls on dune accumulation processes is recognised, and therefore the importance of sampling at multiple locations to distinguish these factors is emphasised.