Functional Nanocomposites Formed by Two-step Back-filling Methods

This thesis investigates the synthesis and properties of nanocomposite materials comprised of inorganic nanocrystals (NCs) combined with a complementary organic compound utilizing sequential two-step synthesis methods. We demonstrate an enhancement in the mechanical and optical properties of electrophoreticially deposited (EPD) cadmium selendide (CdSe) nanocrystal (NC) films through post-deposition addition of organic ligand molecules and polymeric precursor molecules (monomers). Specifically we show that when these organic compounds are added (i.e. back-filled) into the as-deposited, wet EPD NC film, that fracture in the dried film is suppressed and photoluminscent (PL) efficiency of the inorganic NC phase is greatly increased. We go on to study the synthesis and properties of a novel nanocomposite comprised of inorganic NCs back-filled into a mat of semiconducting poly(3-hexylthiophene) [P3HT] nanowires. P3HT nanowire films are synthesized using a novel method developed as part of this thesis; where P3HT is blended with a sacrificial polymer (polystyrene, PS), leading to spontaneous demixing of the two polymers upon casting, and upon selective removal of the PS phase exposes a dense mat of P3HT nanowires. When back filled with CdSe NCs the composite material exhibits photovoltaic (PV) performance and provides a flexible platform for low-cost, hybrid organic/inorganic NC PV device fabrication. We conclude by showing how the above methods, in conjunction with novel ligand chemistry and lithographic techniques, can be utilized to create a photo-active nanocomposite consisting of lithographically defined, micron-scale, electrodes that are selectively decorated with electron-accepting NCs using EPD, and subsequently back-filled with a complementary electron-donating NC phase. The device architecture and resulting nanocomposite material is capable of lateral exciton separation on a potentially low-cost substrate

The history of Methodism in Southern California and Arizona, 1850-1939

Thesis (Ph.D.)--Boston UniversityThis dissertation describes the historical development of Methodism in Southern California and Arizona from its foundation to 1939. It considers major developments, activities, and leadership, and it evaluates these, especially as they have had influence upon the Church; and it evaluates the relative strength and activity of the two branches of Methodism which were present in Southern California and Arizona previous to unification. The history is unfolded in six main divisions: The Methodist Episcopal Church in Southern California Through 1876; The Methodist Episcopal Church, South, in Southern California through 1870; Tihe Methodist Episcopal Church, South, 1870-1939; The Methodist Episcopal Church, 1876-1939; Methodism in Arizona; Unification. While both denominations labored in Southern California before the Civil War--the Methodist Episcopal Church beginning in 1853 and the Methodist Episcopal Church, South, beginning in 1854--the work was spasmodic and was totally reorganized after the war. The Los Angeles Conference of the Southern Church was organized in 1870, and the Southern California Conference of the Northern Church was organized in 1876. Southern Methodism was numerically much weaker than Northern Methodism in Southern California, but its lay organization was considerably more developed. The major project of the Southern Cburch was Trinity Church in Los Angeles. This church was a pioneer in the development of the Epworth League, and two of its pastors became bishops of Southern Methodism. Lack of finances hindered the Southern Church in many fields of endeavor. The Homer Toberman Deaconess Home was its major institutional achievement. Only on the issue of modernism did Southern Methodism here find itself involved in disruptive controversy. Among the leaders of Southern Methodism from Southern California were Grover Emmons, founder of "The Upper Room," and Robert Shuler, one of Methodism's most controversial figures. Northern Methodism grew rapidly and expanded widely after its organization in Southern Galifornia in 1876. Six bishops and numerous educational leaders came from the Southern California conference. Its educational requirements for membership were early among the highest in all Methodism. It was a leader in finding a solution to the entangled pension problem, and it was a pioneer in the matter of minimum salary for the ministry. The founding and developing of the University of Southern California was another notable achievement of the Conference. The outreach of the Conference to other races and nationalities was outstanding. Especially significant were the Church of All Nations, Spanish American Institute, and Plaza Community Center. Nine other institutions, ministering to the sick, the retired, students, and orphans, were established. The Conference did not escape divisive controversies. The most notable of these were: (1) the war issue, leading to the dismissal of a District Superintendent; (2) sanctification, leading to the founding of the Church of the Nazarene. Both denominations entered Arizona in 1870, but work there never assumed the proportions that it did in Sou1thern California. Northern Methodism was the stronger of the two. Hospitals in Phoenix and Tucson were probably the best achievements of both denominations. Unification passed by majority vote in Southern California and Arizona in 1925, but some Southern Methodist opposition was quite noticeable. It passed again in 1938 with several Northern Methodists opposing it because of the proposed inclusion of the Central Jurisdiction. In conclusion, it is evident that the individual 272 Conferences, especially in Southern California,, made important contributions to their respective denominations. It is also apparent that Northern Methodism was considerably stronger than Southern Methodism, expanded further and more rapidly, furnished more leaders to the Church as a whole, and was able to undertake a wider institutional ministry

Regulation of the HCMV UL98 Promoter by Cooperation of the Cyclic AMP Response Element and Gamma Interferon Response Element

The HCMV UL98 early alkaline exonuclease gene promoter was examined to determine the DNA sequences as well as viral and/or cellular proteins functional in the regulation of this early gene. To assess promoter activation, UL98 promoter sequences were first cloned upstream of the chloramphenicol acetyltransferase (CAT) reporter gene and cotransfected with expression plasmids which express the HCMV major immediate early (IE) proteins 1E72 and 1E86. To more specifically determine the importance of individual cis-acting elements in UL98 promoter activation, the promoter region underwent mutagenesis to delete or alter sequences. The variant promoters were again cloned into a reporter-CAT construct and analyzed in transient transfection assays to assess changes in promoter activity in response to viral or virally induced proteins. Analysis of promoter activation indicated that the UL98 promoter required the presence of the IE72 and 1E86 immediate early (IE) proteins. In comparison to a prototypical early promoter which regulates the polymerase (pol) gene, UL98 promoter activation levels were equal to or even greater than that of pol in response to the IE transactivators. In the presence of all viral proteins, activation of the UL98 promoter continually increased when analyzed at 24, 48, and 72 hours. Deletion analysis showed that a 13 by sequence located between −64 and −51 is required for UL98 promoter activation by IE proteins. Site-directed mutations generated in two cellular transcription factor binding sites resulted in a drastic reduction in promoter activation. A mutation in the cyclic AND response element (CRE) (−82 to −75) resulted in a 70% loss of promoter activation. The UL98 promoter was also poorly activated in the presence of a mutation generated in the gamma interferon response element (γIRE) (−37 to −30), a transcription factor binding site downstream of −51. Binding and competition experiments via gel mobility shift assays provided conclusive evidence that the CREB protein binds the CRE site in the UL98 promoter. These data indicate that the UL98 early promoter is regulated primarily by the CRE and gamma IRE sequences. UL98 promoter activation therefore relies upon the presence of a combination of elements in their defined flanking positions

Evolution of a Holocene delta driven by episodic sediment delivery and coseismic deformation, Puget Sound, Washington, USA

This paper is not subject to U.S. copyright. The definitive version was published in Sedimentology 53 (2006): 1211-1228, doi:10.1111/j.1365-3091.2006.00809.x.Episodic, large-volume pulses of volcaniclastic sediment and coseismic subsidence of the coast have influenced the development of a late Holocene delta at southern Puget Sound. Multibeam bathymetry, ground-penetrating radar (GPR) and vibracores were used to investigate the morphologic and stratigraphic evolution of the Nisqually River delta. Two fluvial–deltaic facies are recognized on the basis of GPR data and sedimentary characteristics in cores, which suggest partial emplacement from sediment-rich floods that originated on Mount Rainier. Facies S consists of stacked, sheet-like deposits of andesitic sand up to 4 m thick that are continuous across the entire width of the delta. Flat-lying, highly reflective surfaces separate the sand sheets and comprise important facies boundaries. Beds of massive, pumice- and charcoal-rich sand overlie one of the buried surfaces. Organic-rich material from that surface, beneath the massive sand, yielded a radiocarbon age that is time-correlative with a series of known eruptive events that generated lahars in the upper Nisqually River valley. Facies CF consists of linear sandbodies or palaeochannels incised into facies S on the lower delta plain. Radiocarbon ages of wood fragments in the sandy channel-fill deposits also correlate in time to lahar deposits in upstream areas. Intrusive, sand-filled dikes and sills indicate liquefaction caused by post-depositional ground shaking related to earthquakes. Continued progradation of the delta into Puget Sound is currently balanced by tidal-current reworking, which redistributes sediment into large fields of ebb- and flood-oriented bedforms.This study was supported by the Coastal and Marine Geology Program, and the Earthquake Hazards Program of the U.S. Geological Survey

Abrupt global events in the Earth's history: a physics perspective

The timeline of the Earth's history reveals quasi-periodicity of the geological record over the last 542 Myr, on timescales close, in the order of magnitude, to 1 Myr. What is the origin of this quasi-periodicity? What is the nature of the global events that define the boundaries of the geological time scale? I propose that a single mechanism is responsible for all three types of such events: mass extinctions, geomagnetic polarity reversals, and sea-level fluctuations. The mechanism is fast, and involves a significant energy release. The mechanism is unlikely to have astronomical causes, both because of the energies involved, and because it acts quasi-periodically. It must then be sought within the Earth itself. And it must be capable of reversing the Earth's magnetic field. The last requirement makes it incompatible with the consensus model of the origin of the geomagnetic field - the hydromagnetic dynamo operating in the Earth's fluid core. In the second part of the paper, I show that a vast amount of seemingly unconnected geophysical and geological data can be understood in a unified way if the source of the Earth's main magnetic field is a ~200-km-thick lithosphere, repeatedly magnetized as a result of methane-driven oceanic eruptions, which produce ocean flow capable of dynamo action. The eruptions are driven by the interplay of buoyancy forces and exsolution of dissolved gas, which accumulates in the oceanic water masses prone to stagnation and anoxia. Polarity reversals, mass extinctions, and sequence boundaries are consequences of these eruptions. Unlike the consensus model of geomagnetism, this scenario is consistent with the paleomagnetic data showing that "directional changes during a [geomagnetic polarity] reversal can be astonishingly fast, possibly occurring as a nearly instantaneous jump from one inclined dipolar state to another in the opposite hemisphere".Comment: Final journal version. New title, significant changes. Supersedes v.

Climatic control on palaeohydrology and cyclical sediment distribution in the Plio-Quaternary deposits of the Guadix Basin (Betic Cordillera, Spain)

A cyclical pattern can be observed in the central sector of the Guadix Basin (southern Spain) in the Late Pliocene-Quaternary alluvial fan deposits prograding into its axial valley. A climatic significance has been attributed to this cyclicity on the basis of sedimentological and preliminary isotopic studies. The progradation phases of the alluvial fans are here attributed to more arid time intervals in which the vegetation cover would be less developed, erosion and sediment supply would be higher, and base level would be lower. In contrast, the time intervals during which the fluvial system sediments dominated the area are inferred to be wetter and base level higher, with vegetation cover retaining the soils and preventing erosion. Permanent water supply to the river would therefore facilitate the aggradation of the floodplain and prevent progradation of the fans. Starting from a litho-, bio- and magnetostratigraphical frame provided for the area, an age is assigned to the alternation of the reddish sediments of the transverse alluvial fans and the greyish to white fluvio-lacustrine sediments of the axial drainage system. A cyclicity of ca. 100 ky has been identified in most of the alluvial fan progradation phases, falling within Milankovitch high-frequency eccentricity periodicities. Correlation of the phases with insolation curves is accordingly discussed as a possible origin for the cyclicity. Finally, the results offer new insights into early hominin occupation patterns in the region, through the identification of predictable resources of permanent fresh water that would have remained available throughout the recorded time span (that includes the Early–Middle Pleistocene transition) even during times of aridification.The study was supported by the Project CGL2009-07830/BTE and the Working Group RNM-369JA

Scientific drilling projects in ancient lakes: integrating geological and biological histories

Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information, e.g., through molecular dating of molecular phylogenies. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets for creating an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep drilling projects

Novel 3D sequence stratigraphic numerical model for syn-rift basins: Analysing architectural responses to eustasy, sedimentation and tectonics

Syn-rift clastic sedimentary systems preserve a complicated stratigraphic architecture that records the interplay of tectonics, eustatic sea level and storage and routing of sediments. Previous conceptual models describe and explain changes in depositional stacking patterns along a fault segment. However, stacking patterns, and the nature of key stratigraphic surfaces, is challenging to predict accurately with conventional sequence stratigraphic models that do not consider the three-dimensional interplay of subsidence, sedimentation, and eustasy. We present a novel, geometric, 3D sequence stratigraphic model (‘Syn-Strat’), which applies temporally- and spatially-variable, fault-scale tectonic constraints to stratigraphic forward modelling, as well as allowing flexibility in the other controls in time and space. Syn-Strat generates a 3D graphical surface that represents accommodation. Although the model has the capacity to model footwall variation, here we present model results from the hangingwall of a normal fault, with temporal and spatial (dip and strike) predictions made of stacking patterns and systems tracts for a given set of controls. Sensitivity tests are tied to the depositional architecture of field-based examples from the Loreto Basin, Gulf of California and Alkyonides Basin, Gulf of Corinth. Here, the relative influence of major sedimentary controls, different subsidence histories, varying sedimentation distribution, including along-strike variation in stacking patterns, are assessed and demonstrate the potential of Syn-Strat for reducing subsurface uncertainties by resolving multiple scenarios. In addition, the model demonstrates the nature of diachroneity of key stratigraphic surfaces that can arise in syn-rift settings, which could be represented by a bypass surface (sequence boundary) or reservoir seal (maximum flooding surface) in the rock record. Enabling a quantitative assessment of these surfaces is critical for prospect analysis in hangingwall half-graben-fills, where these surfaces are heavily relied upon for well correlations that are used for hydrocarbon volume and production rate predictions