Topographical constraint is the most powerful approach for the design of bioactive peptides to explore the bioactive conformation of crucial side-chain pharmacophores of amino acid residues in peptide-receptor recognition and signal transduction. Novel topographically constrained amino acids β-isopropylphenylalanine and 2',6'-dimethyl-2,3-methanophenylalanine have been designed and synthesized. Incorporation of the four optically pure β-isopropylphenylalanine stereoisomers into deltorphin I produced four peptide analogues of [β-iPrPhe]Deltorphin I with differentiated bioactivities. The most potent and selective analogue, [(2S,3R)-β-iPrPhe]Deltorphin I showed an IC₅₀ nM binding affinity, and a 29000 fold selectivity for the δ-opioid receptor over the μ opioid receptor. Combined molecular modeling and NMR studies indicated that the (2S,3R)-β-iPrPhe³ residue in the analogue favors the trans rotamer, and can induce the linear peptide to form a low-energy folded conformation which was proposed as the bioactive conformation for the δ-opioid receptor. Coupling four optically pure, conformationally constrained β-methyl-2',6'-dimethyltyrosine (TMT) with L-Tic formed four dipeptide analogues of TMT-L-Tic. The most potent and selective analogue, (2S,3R)-TMT-L-Tic showed 9 nM binding affinity and 4000 fold selectivity to the δ vs μ opioid receptor. The lowest-energy conformation of (2S,3R)-TMT-L-Tic was suggested to be the bioactive one in which TMT side chain is trans and Tic side chain is in a gauche (+) conformation. Bicyclic oxytocin antagonist [dPen¹, cyclo(Glu⁴ Lys⁸)]OT (BC-OT) (pA₂ = 8.10) is an excellent template to examine further topographical ideas. Substitution of Tyr² with the topographically constrained para-methoxy-β-methyl-2',6'-dimethyltyrosine (p-MeOTMT) amino acids produced two very potent antagonists [(2S,3S)-p-MeOTMT²]BC-OT (pA₂ = 8.26) and [(2R,3R)-p-MeOTMT²]BC-OT(pA₂ = 7.80), and two inactive analogues [(2S,3R)-p-MeOTMT²]BC-OT and [(2R,3S)-p-MeOTMT²]BC-OT. These interesting results can be attributed to the biased side-chain conformation, gauche(+) and gauche(-) in (2S,3S)-p-MeOTMT and (2R,3R)-p-MeOTMT respectively, and trans in both (2S,3R)-p-MeOTMT and (2R,3S)-p-MeOTMT residues. Rational design of non-peptide mimetics from peptide leads is still elusive. Based on the δ-opioid selective lead [(2S,3R)-TMT¹]DPDPE and SAR of δ-opioid selective ligands, the first generation of non-peptide mimetics have been designed and synthesized. The new lead SL-3111 showed binding affinity IC₅₀ = 8 nM, and over 2000 fold selectivity for the δ-opioid receptor over the μ receptor.

We provide a realistic assessment of the uncertainties associated with plate reconstructions by creating empirical probability density functions (PDFs) for rotations between plate pairs based upon uncertainties in the positions of observed fracture zone and magnetic anomaly crossings. We determine the PDF for a sequence of rotations through Monte Carlo sampling of the PDFs for these plate pairs. We assign confidence limits within PDFs and find that worst-case uncertainty regions for global reconstruction poles can be twice as large as 95% confidence regions. We illustrate our technique with the anomaly 6 rotation between the Pacific and North American plates and demonstrate that realistic uncertainties for summations of rotations are apt to be significantly smaller than those previously predicted by earlier techniques. We develop revised apparent polar wander paths for the North American and Pacific plates through paleomagnetic Euler pole analysis. We determine motions of the Pacific plate within the hotspot reference frame for the past 80 Ma through a similar analysis and extend the model back to 145 Ma through study of anomalous basement depths and application of the paleomagnetic constraints. The match between the paleomagnetic and hotspot reference frames within uncertainty limits imposed by the available data, contradicts the notion of true polar wander during the late Cretaceous and/or motion between distinct Pacific plates. Applying realistic limits on the expected error in global plate reconstructions, we determine that either the South Atlantic hotspot track is improperly defined, or that there has been more than 1,000 kilometers of relative motion between the Pacific and South Atlantic hotspots since 80 Ma. Our model of plate interactions for the western Americas indicates subduction perpendicular to the margins from 78 Ma to 33 Ma. Northward transpression and transport of allochthonous terranes is limited to regions north of the evolving Pacific-Izanagi (Kula) ridge. We present a series of reconstructions which allows quantification of subduction and lateral transport along the margins. We model the generation of possible oceanic plateaus by known hotspots in the Pacific region and find little evidence to indicate that their subduction had an impact on the magmatic history of North America.

This study describes the impacts of river development projects on land use and vegetation in a floodplain that includes old-growth forest and an important primate habitat located in eastern Kenya. River basin development activities include the construction of hydro-electric dams in the upper river basin, and an irrigation scheme, the Bura Irrigation and Settlement Project, in the lower basin. Through flood frequency analysis for both the pre- and post-dam period, I demonstrate that there has been a significant (p < 0.01) reduction in floods with a recurrence interval of 5 years or greater. A hydrological simulation model is used to estimate the frequency and duration of flooding of 73 vegetation sample plots for the pre- and post-dam period. Four of the plots, lying less than 1.25 m above dry season river level, show a slight increase in days flooded, whereas the rest show a significant decline in days flooded from the pre- to the post-dam period. Detailed descriptions of the structure and dynamics of the Tana riverine forest, and exploration into the influence of abiotic variables to species composition, are made using ordination and classification techniques. The three canopy levels examined, and the regeneration layer, had different species compositions. Many of the upper canopy species are not regenerating. Results of detailed land cover and change detection mapping using remotely sensed data reveal significant change. Forest cover declined slightly (about 2%) between 1975 and 1984. However, between 1989 and 1996, there was a 27% decline in riverine forest, while cultivated area within the forest increased by 45%. Over the same period, area of exposed soil increased by 112%. Several landscape measures are given and all indicate significant fragmentation of riverine forest. The extent of riverine forest along the active river channel declined by about 200 m between 1989 and 1996. Human disturbance now represents the greatest threat to continued survival of the forest. Results of a dendrochronologie investigation reveal that a number of species produce growth rings. Four species identified as offering the best chance for developing a ring-width chronology are; Acacia elatior, Acacia robusta, Tamarindus indica, and Newtonia hildebrandtii.

The Granger causality test was used to explore the price interdependence in the wholesale tomato markets of Fortaleza, Teresina and Sao Luis in the Northeast of Brazil. Following the results of this study, the conclusion is reached that, in general terms, the prices in these markets are established efficiently implying a competitive environment in the Northeast tomato markets. Fortaleza operates as a leading market "driving" the prices of the Teresina and Sao Luis secondary markets.

An examination of light scattering and emissions from a fluorescent dye confined within small hollow core quartz fibers has revealed several interesting phenomena. First, backscattered fluorescent emissions increased as the fiber's inner diameter decreased below 23 microns. Second, interference between the inner and outer fiber walls created angular scattering intensity oscillations in the elastic scattered light and fluorescent emissions. The interference induced oscillations produced large intensity changes in less than a degree. Third, fiber immersion in an index-matched fluid removed the interference oscillations, and fourth, the fiber immersion also decreased the backscattered fluorescent emissions for the same fiber. These research results can be used to optimize the design of fluorescence measuring devices used in capillary zone electrophoresis (CZE). A CZE device measures the fluorescence spectrum from biological material within small hollow core fibers. The small amount of fluorescent material makes it desirable to find an optimum viewing angle to maximize signal and avoid spurious results from selective wavelength enhancement and intensity variations in angular scattering caused by the fiber.

A growing literature suggests that training in relaxation or meditation results in significant reductions in blood pressure in hypertensive patients. The present study was designed to assess the efficacy of a combination relaxation and meditation training program structured by the author and previously used in treatment of a broad spectrum of anxiety-related clinical problems of either a medical (somatic) or a psychological (cognitive and emotional) nature. The 20 subjects were a heterogeneous clinical group of veterans with mild hypertension who were seen at the Tucson Veterans Administration Medical Center. Volunteers were randomly assigned to either (I) an education/cognition group, (II) a three-treatment relaxation/meditation group, or (III) a six-treatment relaxation/meditation group. Blood pressure, anxiety, and stress were measured at regular intervals during training and follow up. All groups were trained over a six-week period. Both relaxation/meditation groups were taught the same skills; only the schedules for training were varied. The educational group, conceived as a control for therapist attention, was, in fact, a cognitive treatment group. Statistically significant reductions in both systolic and diastolic blood pressure were found over time in all groups, while no difference in blood pressure reductions was found among the groups. Anxiety scores increased over time, and no correlation was found between subjective anxiety and objective blood pressure measures. Means of both systolic and diastolic blood pressure were lower at times when subjects reported no stress. Results of this study tend to support those of previous studies, finding statistically significant reductions in systolic and diastolic blood pressure over time in two groups of hypertensive subjects trained in relaxation and meditation techniques. No difference was found, moreover, between these groups and an education/cognition group, suggesting that group techniques, in either significant lowering of blood pressure. This finding lends support to a multiprocess theory which suggests that all treatments have multiple effects.

The key question addressed by this study is: does religion promote political stability or political change? Andrew Greeley's theory of the religious imagination is adopted for the study of religion. Politics is seen as including all those actions and attitudes directed towards the influencing of the making and the execution of policy which deals with concerns in which all members of a society have an interest. These actions and attitudes take the form of either demands or support. The relationships between religion and politics are tested in a secondary analysis of data from an NORC study on religious values conducted in 1979. The American nationwide sample of Catholics and former Catholics aged 18 to 19 are examined. Models of hypothesized relationships are tested by using path analysis based on ordinary least-square regression. After the models are tested for Catholics, Catholic disidentifiers, males, females, Germans, Irish, and Italians. The results demonstrate that religion may, given the content of that religion, promote either political stability or political change. The influence of religion on politics is contingent upon the content of that religion, particularly upon the religious imagery held by the respondents. Conventional images of God for the most part increase levels of confidence in the political authorities. These images contribute to political stability. When religious imagery has an influence on the view that the church and its functionaries should articulate progressive socio-political demands it is warm religious imagery. Warm images of God can contribute to the promotion of political change. Conventional images of God, for males and Italians, contribute to higher levels of conventional political participation. Warm images of God, for females and Germans, also have a positive influence on conventional political participation. This study demonstrates the need to include religion as an important consideration to be examined in any inquiry into the generation of demands and supports into the political system. It also provides a framework for the investigation of religion's influence on politics in cross-national and cross-cultural research.