953 resultados para Research formation multireferential
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This dissertation explores the Rastafari movement and the Nation of Islam as institutions that provide a group-identity for their adherents. The study seeks to determine the characteristics of the identity that is institutionalized by each movement, and the nature of the institutionalization process. The research was conducted primarily in South Florida where both movements exist. An extensive literature review in conjunction with in-depth field interviews were used as the primary research methodologies. What was of particular interest were the reasons that the members of the movements chose one movement over the other, also the similarities and dissimilarities between the movements in their role as institutions for group-identity formation. The research showed that both movements imbued their members with a sense of pride, high self-esteem and a strong sense of race consciousness. In addition, it showed that there was significant variation in identity orientation within the Rastafari Movement, which contrasted with the Nation of Islam where the identity variations within the movement were negligible. This was due largely to the difference in structure between the movements, the Nation of Islam being a centrally organized movement with one leader while the Rastafari movement is a decentralized polycephalous one. Both movements were found to be millenarian in nature, essentially because of the significant utility of the concept that their members would rise to prominence through God's grace. Additionally, both movements were identified as expressive social movements, since they were determined as being primarily concerned with changing the attitudes of their members rather than effecting structural social change.
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Literary researcher and professor Zeila Frade gives a lecture analyzing the relationship among children's literature, ideology, and cultural identity in Cuba.
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This study examined the perceptions of state governmental officials and administrators from the state university system, community college system, and independent institutions concerning the ability of various groups to influence state-level higher education policy formation. The study was conducted in Florida for the period 1989-94. Florida has a history of legislative involvement in higher education, an unique system of state universities and community colleges, and a limited number of private institutions of higher education. This study was grounded in the works of Mortimer and McConnell (1978), Millett (1987), Marshall, Mitchell, and Wirt (1989) and Finitfer, Baldwin, and Thelin (1991). The study represented the application of an embedded, single-case design. A survey was the primary collection instrument. Respondents were asked questions concerning: (a) personal involvement in higher education, (b) perceptions of the ability of various groups to influence higher education policy, (c) the names of particular individuals considered key players in higher education policy formation, (d) important state-level documents, (e) personal knowledge of key areas of policy formation, and (f) emerging higher education issues in Florida. Quantitative and qualitative methods were used to analyze the different sections of the survey. The findings indicated that a power and influence hierarchy exists among the various groups that attempt to influence higher education policy and that this hierarchy is recognized by state government officials and higher education administrators. While an analysis of variance of the various groups revealed a few differences between state government officials and higher education personnel, the high overall agreement was an important finding. Leading members of the legislature, especially the Chair of the Senate Higher Education Committee, and key staff members, especially from the Senate Ways & Means Committee, were considered the most influential. Representatives from higher education institutions and research organizations were considered among the least influential. Emerging issues identified by the respondents included: (a) the political nature of state-level policy formation, (b) the role of legislative staff, (c) the competition for state moneys, (d) legislative concern for state-wide budgetary efficiency, and (e) legislative attempts to define quality and supervise academic program development for higher education.
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In oil and gas pipeline operations, the gas, oil, and water phases simultaneously move through pipe systems. The mixture cools as it flows through subsea pipelines, and forms a hydrate formation region, where the hydrate crystals start to grow and may eventually block the pipeline. The potential of pipe blockage due to hydrate formation is one of the most significant flow-assurance problems in deep-water subsea operations. Due to the catastrophic safety and economic implications of hydrate blockage, it is important to accurately predict the simultaneous flow of gas, water, and hydrate particles in flowlines. Currently, there are few or no studies that account for the simultaneous effects of hydrate growth and heat transfer on flow characteristics within pipelines. This thesis presents new and more accurate predictive models of multiphase flows in undersea pipelines to describe the simultaneous flow of gas, water, and hydrate particles through a pipeline. A growth rate model for the hydrate phase is presented and then used in the development of a new three-phase model. The conservation equations of mass, momentum, and energy are formulated to describe the physical phenomena of momentum and heat transfer between the fluid and the wall. The governing equations are solved based on an analytical-numerical approach using a Newton-Raphson method for the nonlinear equations. An algorithm was developed in Matlab software to solve the equations from the inlet to the outlet of the pipeline. The developed models are validated against a single-phase model with mixture properties, and the results of comparative studies show close agreement. The new model predicts the volume fraction and velocity of each phase, as well as the mixture pressure and temperature profiles along the length of the pipeline. The results from the hydrate growth model reveal the growth rate and location where the initial hydrates start to form. Finally, to assess the impact of certain parameters on the flow characteristics, parametric studies have been conducted. The results show the effect of a variation in the pipe diameter, mass flow rate, inlet pressure, and inlet temperature on the flow characteristics and hydrate growth rates.
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Formation of hydrates is one of the major flow assurance problems faced by the oil and gas industry. Hydrates tend to form in natural gas pipelines with the presence of water and favorable temperature and pressure conditions, generally low temperatures and corresponding high pressures. Agglomeration of hydrates can result in blockage of flowlines and equipment, which can be time consuming to remove in subsea equipment and cause safety issues. Natural gas pipelines are more susceptible to burst and explosion owing to hydrate plugging. Therefore, a rigorous risk-assessment related to hydrate formation is required, which assists in preventing hydrate blockage and ensuring equipment integrity. This thesis presents a novel methodology to assess the probability of hydrate formation and presents a risk-based approach to determine the parameters of winterization schemes to avoid hydrate formation in natural gas pipelines operating in Arctic conditions. It also presents a lab-scale multiphase flow loop to study the effects of geometric and hydrodynamic parameters on hydrate formation and discusses the effects of geometric and hydrodynamic parameters on multiphase development length of a pipeline. Therefore, this study substantially contributes to the assessment of probability of hydrate formation and the decision making process of winterization strategies to prevent hydrate formation in Arctic conditions.
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Five long piston cores collected from different subbasins of the Aegean Sea constitute the primary source of data for this PhD thesis. This study is the first to document a continuous paleoceanographic and paleoclimatic record of the Aegean Sea since the last interglacial. The chronostratigraphic reconstructions of the cored sediments based on organic carbon contents, stratigraphic position of known ash layers and oxygen isotopic curve matching collectively demonstrate the presence of sapropel S1 and MISS sapropels S3, S4 and S5 in the Aegean Sea subbasins. Generally, the organic carbon (TOC wt%) contents in sapropels range between 0.8% and 2% with highest concentrations of 9-13% in sapropels S4 and S5. Average sedimentation rates range between 4.7 and 11.8 cmlka with highest rates being observed in Euboea and North Ikaria basins (9.8 and 11.8 cm lka, respectively). The timing of the onset of sapropels S4 and S5 mostly predate those in the eastern Mediterranean with ages ranging from 106.4-105.6 and 128.6-128.4 ka BP, respectively. On the other hand, the initiation of the onset of sapropel S3 (i.e., 83.2-80.4 ka BP) seems to agree with its Mediterranean counterparts, which highlights the heterogeneity of the Aegean Sea subbasins in terms of rapid vs. lagged response to changing climatic conditions. The sapropel initiations appear to be synchronous across the Aegean Sea; whereas, the terminations display a wider temporal variability implying that the cessation of sapropels is controlled both by the amplitude of paleoclimatic changes and the physiography/location ofthe subbasins. Quantitative variations in the planktonic faunal assemblages exhibit a sequence of bioevents during the last -130,000 years which allow identification of four major biozones. The distributional patterns of the most significant taxa demonstrate similar trends among all core localities suggesting that the major changes in the planktonic foraminifera assemblages have taken place rather synchronously in the Aegean Sea. Sapropels S3, S4 and S5 were deposited under similar hydrographic conditions during which a distinct deep chlorophyll maximum (DCM) layer was established. This situation points to a stratified water column and increased export productivity during times of sapropel formation. On the other hand, the faunal contrast between Sl and older sapropels indicates that the former was developed in the absence of a DCM layer, lacking a deep phytoplankton assemblage. Under such conditions, oxygen advection via intermediate water flow must have been significantly reduced which implies significant stagnation. Sapropels are interpreted to have been deposited under normal marine conditions with temporary establishment of semi-euxinic bottom water conditions. Both marine and terrestrial organic matter contributed equally to MISS sapropels. In addition, organic carbon isotopic values across sapropels are more depleted than those in the eastern Mediterranean which, in tum, suggests enhanced riverine input during their deposition. Primary productivity calculations show that, particularly for sapropels with very high TOC values, both preservation and increased productivity are imperative in order to deposit sapropels with very high organic carbon contents (i.e., up to 13%).
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In this study, we investigate phosphorus (P) and iron (Fe) cycling in sediments along a depth transect from within to well below the oxygen minimum zone (OMZ) in the northern Arabian Sea (Murray Ridge). Pore-water and solid-phase analyses show that authigenic formation of calcium phosphate minerals (Ca-P) is largely restricted to where the OMZ intersects the seafloor topography, likely due to higher depositional fluxes of reactive P. Nonetheless, increased ratios of organic carbon to organic P (Corg/Porg) and to total reactive P (Corg/Preactive) in surface sediments indicate that the overall burial efficiency of P relative to Corg decreases under the low bottom water oxygen concentrations (BWO) in the OMZ. The relatively constant Fe/Al ratio in surface sediments along the depth transect suggest that corresponding changes in Fe burial are limited. Sedimentary pyrite contents are low throughout the ~25 cm sediment cores at most stations, as commonly observed in the Arabian Sea OMZ. However, pyrite is an important sink for reactive Fe at one station in the OMZ. A reactive transport model (RTM) was applied to quantitatively investigate P and Fe diagenesis at an intermediate station at the lower boundary of the OMZ (bottom water O2: ~14 µmol/L). The RTM results contrast with earlier findings in showing that Fe redox cycling can control authigenic apatite formation and P burial in Arabian Sea sediment. In addition, results suggest that a large fraction of the sedimentary Ca-P is not authigenic, but is instead deposited from the water column and buried. Dust is likely a major source of this Ca-P. Inclusion of the unreactive Ca-P pool in the Corg/P ratio leads to an overestimation of the burial efficiency of reactive P relative to Corg along the depth transect. Moreover, the unreactive Ca-P accounts for ~85% of total Ca-P burial. In general, our results reveal large differences in P and Fe chemistry between stations in the OMZ, indicating dynamic sedimentary conditions under these oxygen-depleted waters.
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This study was developed under the ExxonMobil FC2 Alliance (Fundamental Controls on Flow in Carbonates). The authors wish to thank ExxonMobil Production Company and ExxonMobil Upstream Research Company for providing funding. The views in this article by Sherry L. Stafford are her own and not necessarily those of ExxonMobil. This research was supported by the Sedimentary Geology Research Group of the Generalitat de Catalunya (2014SGR251). We would like to thank Andrea Ceriani and Paola Ronchi for their critical and valuable reviews, and Associated Editor Piero Gianolla for the editorial work.
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Acknowledgements: Funding for this project was provided from the Research Council of Norway through the Petromaks project 193059 and the FORCE Safari Project. Arild Andresen (University of Oslo) and Aka Lynge (POLOG) are thanked for logistical support, Björn Nyberg (Uni Research CIPR and University of Bergen) for assistance in the field, Arve Næss (Statoil) for providing data and assistance during the planning phase, Julien Vallet and Huges Fournier (Helimap Systems SA) for data acquisition. Riegl LMS GmbH is acknowledged for software support. We thank Brian Willis and an anonymous reviewer for their insightful and thorough reviews and Mariano Marzo for editorial comments.
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Acknowledgements: Funding for this project was provided from the Research Council of Norway through the Petromaks project 193059 and the FORCE Safari Project. Arild Andresen (University of Oslo) and Aka Lynge (POLOG) are thanked for logistical support, Björn Nyberg (Uni Research CIPR and University of Bergen) for assistance in the field, Arve Næss (Statoil) for providing data and assistance during the planning phase, Julien Vallet and Huges Fournier (Helimap Systems SA) for data acquisition. Riegl LMS GmbH is acknowledged for software support. We thank Brian Willis and an anonymous reviewer for their insightful and thorough reviews and Mariano Marzo for editorial comments.
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Germanium (Ge) nanowires are of current research interest for high speed nanoelectronic devices due to the lower band gap and high carrier mobility compatible with high K-dielectrics and larger excitonic Bohr radius ensuing a more pronounced quantum confinement effect [1-6]. A general way for the growth of Ge nanowires is to use liquid or a solid growth promoters in a bottom-up approach which allow control of the aspect ratio, diameter, and structure of 1D crystals via external parameters, such as precursor feedstock, temperature, operating pressure, precursor flow rate etc [3, 7-11]. The Solid-phase seeding is preferred for more control processing of the nanomaterials and potential suppression of the unintentional incorporation of high dopant concentrations in semiconductor nanowires and unrequired compositional tailing of the seed-nanowire interface [2, 5, 9, 12]. There are therefore distinct features of the solid phase seeding mechanism that potentially offer opportunities for the controlled processing of nanomaterials with new physical properties. A superior control over the growth kinetics of nanowires could be achieved by controlling the inherent growth constraints instead of external parameters which always account for instrumental inaccuracy. The high dopant concentrations in semiconductor nanowires can result from unintentional incorporation of atoms from the metal seed material, as described for the Al catalyzed VLS growth of Si nanowires [13] which can in turn be depressed by solid-phase seeding. In addition, the creation of very sharp interfaces between group IV semiconductor segments has been achieved by solid seeds [14], whereas the traditionally used liquid Au particles often leads to compositional tailing of the interface [15] . Korgel et al. also described the superior size retention of metal seeds in a SFSS nanowire growth process, when compared to a SFLS process using Au colloids [12]. Here in this work we have used silver and alloy seed particle with different compositions to manipulate the growth of nanowires in sub-eutectic regime. The solid seeding approach also gives an opportunity to influence the crystallinity of the nanowires independent of the substrate. Taking advantage of the readily formation of stacking faults in metal nanoparticles, lamellar twins in nanowires could be formed.
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Episodic memory formation is shaped by expectation. Events that generate expectations have the capacity to influence memory. Additionally, whether subsequent events meet or violate expectations has consequences for memory. However, clarification is still required to illuminate the circumstances and direction of memory modulation. In the brain, the mechanisms by which expectation modulates memory formation also require consideration. The dopamine system has been implicated in signaling events associated with different states of expectancy; it has also been shown to modulate episodic memory formation in the hippocampus. Thus, the studies included in this dissertation utilized both functional magnetic resonance imaging (fMRI) and behavioral testing to examine when and how the dopaminergic system supports the modulation of memory by expectation. The work aimed to characterize the activation of dopaminergic circuitry in response to cues that generate expectancy, during periods of anticipation, and in response to outcomes that resolve expectancy. The studies also examined how each of these event types influenced episodic memory formation. The present findings demonstrated that novelty and expectancy violation both drive dopaminergic circuitry capable of contributing to memory formation. Consistent with elevated dopaminergic midbrain and hippocampus activation for each, expected versus expectancy violating novelty did not differentially affect memory success. We also showed that high curiosity expectancy states drive memory formation. This was supported by activation in dopaminergic circuitry that was greater for subsequently remembered information only in the high curiosity state. Finally, we showed that cues that generate high expected reward value versus high reward uncertainty differentially modulate memory formation during reward anticipation. This behavioral result was consistent with distinct temporal profiles of dopaminergic action having differential downstream effects on episodic memory formation. Integrating the present studies with previous research suggests that dopaminergic circuitry signals events that are unpredicted, whether cuing or resolving expectations. It also suggests that contextual differences change the contribution of the dopaminergic system during anticipation, depending on the nature of the expectation. And finally, this work is consistent with a model in which dopamine elevation in response to expectancy events positively modulates episodic memory formation.
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Although anthropogenic infuences such as global warming, overfishing, and eutrophication may contribute to jellyfish blooms, little is known about the effects of ocean acidification on jellyfish. Most medusae form statoliths of calcium sulfate hemihydrate that are components of their balance organs (statocysts). This study was designed to test the effects of pH (7.9, within the average current range, 7.5, expected by 2100, and 7.2, expected by 2300) combined with two temperatures (9 and 15°C) on asexual reproduction and statolith formation of the moon jellyfish, Aurelia labiata. Polyp survival was 100% after 122 d in seawater in all six temperature and pH combinations. Because few polyps at 9°C strobilated, and temperature effects on budding were consistent with published results, we did not analyze data from those three treatments further. At 15°C, there were no significant effects of pH on the numbers of ephyrae or buds produced per polyp or on the numbers of statoliths per statocyst; however, statolith size was signi?cantly smaller in ephyrae released from polyps reared at low pH. Our results indicate that A. labiata polyps are quite tolerant of low pH, surviving and reproducing asexually even at the lowest tested pH; however, the effects of small statoliths on ephyra fitness are unknown. Future research on the behavior of ephyrae with small statoliths would further our understanding of how ocean acidi?cation may affect jellyfish survival in nature.
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The paper investigates how Information Systems (IS) has emerged as the product of inter-disciplinary discourses. The research aim in this study is to better understand diversity in IS research, and the extent to which the diversity of discourse expanded and contracted from 1995 to 2011. Methodologically, we apply a combined citations/co-citations analysis based on the eight Association for Information Systems basket journals and the 22 subject-field classification framework provided by the Association of Business Schools. Our findings suggest that IS is in a state of continuous interaction and competition with other disciplines. General Management was reduced from a dominant position as a reference discipline in IS at the expense of a growing variety of other discourses including Business Strategy, Marketing, and Ethics and Governance, among others. Over time, IS as a field moved from the periphery to a central position during its discursive formation. This supports the notion of IS as a fluid discipline dynamically embracing a diverse range of adjacent reference disciplines, while keeping a degree of continuing interaction with them. Understanding where IS is currently at allows us to better understand and propose fruitful avenues for its development in both academia and practice. © 2013 JIT Palgrave Macmillan All rights reserved.
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The Cutri Formation’s, type location, exposed in the NW of Mallorca, Spain has previously been described by Álvaro et al., (1989) and further interpreted by Abbots (1989) unpublished PhD thesis as a base-of-slope carbonate apron. Incorporating new field and laboratory analysis this paper enhances this interpretation. From this analysis, it can be shown without reasonable doubt that the Cutri Formation was deposited in a carbonate base-of-slope environment on the palaeowindward side of a Mid-Jurassic Tethyan platform. Key evidence such as laterally extensive exposures, abundant deposits of calciturbidtes and debris flows amongst hemipelagic deposits strongly support this interpretation.