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Modeling Particle Filtration And Caking In Fibrous Filter Media, Seyed Alireza Hosseini Jul 2011

Modeling Particle Filtration And Caking In Fibrous Filter Media, Seyed Alireza Hosseini

Theses and Dissertations

This study is aimed at developing modeling methodologies for simulating the flow of air and aerosol particles through fibrous filter media made up of micro- or nano-fibers. The study also deals with modeling particle deposition (due to Brownian diffusion, interception, and inertial impaction) and particle cake formation, on or inside fibrous filters. By computing the air flow field and the trajectory of airborne particles in 3-D virtual geometries that resemble the internal microstructure of fibrous filter media, pressure drop and collection efficiency of micro- or nano-fiber filters are simulated and compared with the available experimental studies. It was demonstrated that …

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Intracellular Signaling Contributions To Behaviors Relevant To Nicotine Addiction, Lauren Thompson Jul 2011

Intracellular Signaling Contributions To Behaviors Relevant To Nicotine Addiction, Lauren Thompson

Theses and Dissertations

Nicotine is the primary addictive substance in tobacco, and most smokers who quit will relapse within a year. Evidence shows that cigarette craving increases over time, termed “incubation.” The purpose of these studies was to see if protracted abstinence from chronic nicotine increases rat self-administration, an animal model with good face validity for human tobacco use, and if nicotine self-administration during daily exposure/after 8+ days of abstinence is regulated by extracellular signal-regulated kinase (ERK) signaling in the nucleus accumbens (NAc) shell or anterior cingulate cortex (PFC). ERK kinase inhibitor U0126 was infused in the NAc shell or PFC of Long …

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Developing A Hybrid Model To Predict Student First Year Retention And Academic Success In Stem Disciplines Using Neural Networks, Ruba Alkhasawneh Jul 2011

Developing A Hybrid Model To Predict Student First Year Retention And Academic Success In Stem Disciplines Using Neural Networks, Ruba Alkhasawneh

Theses and Dissertations

Understanding the reasoning behind the low enrollment and retention rates of Underrepresented Minority (URM) students (African Americans, Hispanic Americans, and Native Americans) in the disciplines of science, technology, engineering, and mathematics (STEM) has concerned many researchers for decades. Numerous studies have used traditional statistical methods to identify factors that affect and predict student retention. Recently, researchers have relied on using data mining techniques for modeling student retention in higher education [1]. This research has used neural networks for performance modeling in order to obtain an adequate understanding of factors related to first year academic success and retention of URM at …

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Novel Methodology For Assessing Phytoplankton Response To Pco2 Enrichment In Fresh And Saltwater, Susan B. Gifford Jul 2011

Novel Methodology For Assessing Phytoplankton Response To Pco2 Enrichment In Fresh And Saltwater, Susan B. Gifford

Theses and Dissertations

Atmospheric CO2 emissions are on the rise and are expected to reach 780 parts per million by the year 2100. Research investigating the impacts of increasing CO2 is a relatively new field and the response of phytoplankton communities is largely unknown, especially in coastal and freshwater ecosystems where no CO2 manipulation studies have completed. The present study attempts to encourage uniformity in methods utilized in CO2 perturbation studies and identifies changes in phytoplankton abundance in freshwater (James River) and coastal ocean (Atlantic, Cape Hatteras) sites. A novel bubbling method to manipulate pCO2 was compared with the classic method of acid …

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Analysis And Fingerprinting Of Glycosaminoglycans, Joseph King Jul 2011

Analysis And Fingerprinting Of Glycosaminoglycans, Joseph King

Theses and Dissertations

Heparin is a complex mixture of sulfated polysaccharides derived from animals and one of the oldest drugs in use. While an efficacious anticoagulant, heparin is beset by side effects and pharmacokinetic difficulties. Low molecular weight heparins (LMWH) are made by depolymerizing unfractionated heparin (UFH) and present improvements in these areas. However, they still retain a phenomenally high level of complexity due to their polydispersity and the introduction of non-native structural features. This makes the structural characterization LMWHs a daunting task. This work details the development of a novel capillary electrophoretic (CE) method for fingerprinting LMWHs. Since their complexity normally results …

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Role Of Tyk2 In The Development Of Beige Cells, Samantha Umali Jul 2011

Role Of Tyk2 In The Development Of Beige Cells, Samantha Umali

Theses and Dissertations

Obesity results from an excess of adipose tissue and is a major risk factor for type 2 diabetes, cardiovascular disease, and cancer. Adipose tissue exists in two main forms: white adipose tissue (WAT), which stores energy as triglycerides, and brown adipose tissue (BAT), which dissipates stored energy as heat. White adipose tissue is composed of several subcutaneous and visceral depots, each possessing distinct molecular and functional characteristics. Brown-like adipocytes can emerge in WAT depots in response to cold or beta-adrenergic stimulation. These cells have been called “beige” or “brite” (brown-in-white) cells. The reduction of obesity in mice treated with beta-adrenergic …

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Racial Differences In The Genetics Of Preeclampsia, Lori Hill Jul 2011

Racial Differences In The Genetics Of Preeclampsia, Lori Hill

Theses and Dissertations

Preeclampsia (PE), characterized by hypertension and proteinuria after 20 weeks of gestation, affects 5-8% of pregnancies worldwide. Although preeclampsia is a significant cause of maternal and perinatal mortality and morbidity, its etiology remains to be elucidated. Racial differences have been observed for preeclampsia, with U.S. Blacks having higher rates and more severe disease, compared to U.S. Whites and Hispanics. One potential source of racial differences in preeclampsia is genetic variation between populations. Genetic susceptibility to preeclampsia is well established, but the specific contributions of maternal vs. fetal genes, and how these vary among racial groups is poorly understood. This dissertation …

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Sythesis And Biological Screening Of A Series Of Novel Chemokine Receptor Ccr5 Antagonists, Soundarya Vaithianathan Jul 2011

Sythesis And Biological Screening Of A Series Of Novel Chemokine Receptor Ccr5 Antagonists, Soundarya Vaithianathan

Theses and Dissertations

The chemokine receptor CCR5 has been implicated in the pathogenesis of cancers and AIDS. A series of novel piperidine derivatives were designed, synthesized, and evaluated as CCR5 antagonists. The ability of the new ligands to inhibit the increment of intracellular calcium level stimulated by endogenous ligand CCL5 was measured in the calcium mobilization assay as an indication of its CCR5 receptor antagonism. The anti-proliferation assay was performed to measure the ability of these new compounds to inhibit the proliferation of prostate cancer cell lines, PC-3 and M12. A new lead compound has been identified which showed micromolar level of inhibition …

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Ecological Profiling Of Bird-Mosquito Interactions In Central Virginia, Anna Riggan Jul 2011

Ecological Profiling Of Bird-Mosquito Interactions In Central Virginia, Anna Riggan

Theses and Dissertations

Current methods of mosquito surveillance estimate general population abundances, but fail to represent the relationship of vector abundance to host density important to determining transmission risk of mosquito-borne pathogens (MBP). We sought to address this limitation by creating a novel mosquito trap that directly sampled mosquitoes seeking to feed on nesting birds. The primary objectives of this study were to (1) assess the efficiency of the Nest Mosquito Trap (NMT) and how this is affected by nest box size. (2) assess whether the NMT affects bird, specifically nest success in Prothonotary Warblers (Protonotaria citrea), and adult behavior. (3) compare our …

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Synthesis Of A Library Of Sulfated Small Molecules, Shrenik Mehta Jul 2011

Synthesis Of A Library Of Sulfated Small Molecules, Shrenik Mehta

Theses and Dissertations

The discovery of heparin in 1916 resulted in a huge impact on the practice of medicine. Heparin has played a major role in alleviating thrombotic disorders and has also exhibited effects on almost every major system in the human body. Over the past few decades, more and more heparin-protein interactions have come to light. It is implicated to modulate several important processes such as cell growth and differentiation, inflammatory response, viral infection mechanism etc. More interesting is the observation that these interactions are considerably specific with regard to oligosaccharide sequences which have specific spatially oriented sulfate groups modulating the responses. …

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Investigation Of Pre- And Post-Zygotic Reproductive Barriers Between Two Host-Plant Complex Races Of The Parasitic Wasp Cotesia Congregata (Say) [Hymenoptera: Braconidae], Justin Bredlau Jul 2011

Investigation Of Pre- And Post-Zygotic Reproductive Barriers Between Two Host-Plant Complex Races Of The Parasitic Wasp Cotesia Congregata (Say) [Hymenoptera: Braconidae], Justin Bredlau

Theses and Dissertations

Investigations of host-associated differentiation of parasitoids have largely focused on the degree of molecular genetic differentiation, but a true test of species status must examine the mating patterns of differentiated populations to determine if they can interbreed in the wild and produce viable offspring. We examined possible mechanisms of isolation between two genetically distinct host-plant complex races of the braconid, Cotesia congregata, originating from hosts on tobacco and catalpa. We compared male responses to female pheromones, elements of male acoustic courtship signals, and breeding success between the two races. Males responded to pheromones from both sources and male courtship signals …

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Characterization Of Lysophosphatidic Acid Subspecies Using A Novel Hplc Esi-Ms/Ms Method, Eric Mayton Jul 2011

Characterization Of Lysophosphatidic Acid Subspecies Using A Novel Hplc Esi-Ms/Ms Method, Eric Mayton

Theses and Dissertations

Lysophosphatidic acid (LPA) is a bioactive lipid with a plethora of biological functions, including roles in cell survival, proliferation, and migration. Although high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC ESI-MS/MS) technology has been used to measure the levels of LPA in human blood, serum and plasma, current methods cannot readily detect the minute levels of LPA from cell culture. In this study, a novel HPLC ESI-MS/MS method with enhanced sensitivity was developed which allows accurate measurements of LPA levels with a limit of quantitation at approximately 10 femtomoles. The method was validated by quantitation of LPA levels in …

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Receptor Influences In Girk Current Activation And Desensitization, Gyu Park Jul 2011

Receptor Influences In Girk Current Activation And Desensitization, Gyu Park

Theses and Dissertations

G protein-coupled receptors (GPCRs) are seven-transmembrane domain receptors that sense extracellular signal and activate intracellular signaling pathways. Metabotropic glutamate receptor 2 (mGluR2) is one of the GPCRs coupled to Gi/o proteins whose Gβγ subunits stimulate G protein-gated inwardly rectifying K+ channels (GIRKs). Previous experiments demonstrated that in planar lipid bilayer both active forms of G proteins [Gα (GTPγS-stimulated) and Gβγ subunits] were required to activate GIRK channels in the absence of the receptor, but surprisingly, the Gβγ subunit alone could activate GIRK channel in the presence of GPCR. Currently, it is not clear whether GPCRs play a role beyond catalyzing …

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Growth Of Age-0 Atlantic Menhaden (Brevoortia Tyrannus) In Two Tidal Freshwater Tributaries Of Chesapeake Bay, Peter M. Sturke Jul 2011

Growth Of Age-0 Atlantic Menhaden (Brevoortia Tyrannus) In Two Tidal Freshwater Tributaries Of Chesapeake Bay, Peter M. Sturke

Theses and Dissertations

Few studies have described growth rates of age-0 Atlantic menhaden (Brevoortia tyrannus). Growth rates from tidal freshwater habitats of the Mattaponi and James Rivers, Virginia in 2009 were described and compared using otolith microstructural analyses. Larval tidal freshwater growth rates were significantly faster in the culturally eutrophic James River when compared to those collected from the Mattaponi River (p-value < 0.001). Elevated primary production within tidal freshwater habitats promotes favorable conditions for larval Atlantic menhaden growth. No differences between river habitats for juvenile growth rates were evident. Comparisons of age-0 growth rates to higher salinity habitats indicate that tidal freshwater habitats should be considered essential habitat for age-0 Atlantic menhaden.

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The Professional Identity Development Of Gerontologists: An Experiential Learning Approach, Tracey Gendron Jul 2011

The Professional Identity Development Of Gerontologists: An Experiential Learning Approach, Tracey Gendron

Theses and Dissertations

Professional identity is a complex construct that describes how an individual develops a sense of self-concept within a chosen profession. Professional identity refers to a self definition within a professional role based on attributes, beliefs, values, motives, and experiences (Ibarra, 1999). This study explored the relationships between the professional identity of gerontology graduates and age, career stage, student typology, occupation, and value of experiential learning both quantitatively and qualitatively. Survey results indicate that experiential learning opportunities provide a framework for all gerontology students to gain and apply the skills and knowledge necessary for professional identity development in the field of …

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Commonwealth Times 2011-07-01 Jul 2011

Commonwealth Times 2011-07-01

Commonwealth Times, 1969-

No abstract provided.

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Rural Hospital System Affiliations And Their Effects On Hospital Economic Performance, 2004-2008, Mark Swofford Jun 2011

Rural Hospital System Affiliations And Their Effects On Hospital Economic Performance, 2004-2008, Mark Swofford

Theses and Dissertations

The formation of multi-hospital systems represents one of the largest structural changes in the hospital industry. As of 2008, system affiliated hospitals outnumbered stand alone hospitals 2511 to 2167 and the percentage of system affiliated rural hospitals has increased dramatically from 24.8% in 1983 to 42.2% in 2008 (based on AHA data for non-federal acute care general hospitals). The effects of system membership on hospital performance have been of great interest to health care researchers, but the majority of research on multi-hospital systems has either focused exclusively on urban facilities or pooled urban and rural facilities in the same sample, …

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Differential Glial Cell Responses In The Dentate Gyrus In Young Adult And Aged Brains Following Traumatic Brain Injury, Christoher Shin Jun 2011

Differential Glial Cell Responses In The Dentate Gyrus In Young Adult And Aged Brains Following Traumatic Brain Injury, Christoher Shin

Theses and Dissertations

Traumatic brain injury (TBI) affects 3 out of every 1000 Americans each year, and is the leading cause of morbidity and mortality after trauma, accounting for as many as 56,000 deaths per year (Dutton and McCunn, 2003). The Centers for Disease and Control and Prevention found that TBI most commonly occurs in adolescents and young adults aged from 15 to 24 years and in the elderly (75 years and older). Following injury, the secondary injury begins almost immediately after the primary injury and is the result of a number of cascades where once activated, exacerbate the already altered homeostasis of …

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Microbial Community Function In Freshwater Wetland Soils: Using Extracellular Enzyme Analysis To Study The Effect Of Moisture And Vegetation, Aaron Porter Jun 2011

Microbial Community Function In Freshwater Wetland Soils: Using Extracellular Enzyme Analysis To Study The Effect Of Moisture And Vegetation, Aaron Porter

Theses and Dissertations

Differences in microbial function via extracellular enzyme activity (EEA) were investigated to determine the potential effects of hydrology and plant-soil-microbe interactions in a young non-tidal freshwater riparian wetland. To study these relationships, three plots were established along a moisture gradient (Wet, Intermediate, Dry) within VCU Rice Center Within each main plot, five subplots were left undisturbed while another five were cleared of all above-ground plant biomass. Homogenized soil cores (top 10 cm) were analyzed for pH, redox, C:N, soil organic matter (SOM) content, saturation, and temperature. Microbial function was assessed using extracellular enzyme analysis. For most enzymes, a site difference …

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Optimization Of A Tri-Layered Vascular Graft: The Influence Of Cellular And Mechanical Properties, Michael Mcclure Jun 2011

Optimization Of A Tri-Layered Vascular Graft: The Influence Of Cellular And Mechanical Properties, Michael Mcclure

Theses and Dissertations

Electrospinning is a polymer processing technique which allows for the production of nano to micro size fibers and scaffolds which can be composed of numerous synthetic biodegradable materials and natural biopolymers. Natively, elastin and collagen are the main components of vascular tissue. Arranged in a tri-layered structure, they create a specific mechanical environment that can withstand the rigors of circulation. The goal of this study was to develop a mechanically ‘biomimicking’ vascular graft composed of three distinct layers through the process of electrospinning. We hypothesize that the use of bioactive agents such as elastin, collagen, and silk to supplement poly(caprolactone) …

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Cis 3,4', 5-Trimethoxy-3'-Aminostilbene (Stilbene 5c) Induces Apoptosis And Protective Autophagy In B16f10 Melanoma Cells, Betelehem Asnake Jun 2011

Cis 3,4', 5-Trimethoxy-3'-Aminostilbene (Stilbene 5c) Induces Apoptosis And Protective Autophagy In B16f10 Melanoma Cells, Betelehem Asnake

Theses and Dissertations

The weak selectivity of chemotherapeutic drugs against tumors has sustained efforts to develop better chemotherapeutic agents that are more potent and selective at destroying tumor cell populations versus normal tissues. This project focuses on evaluating the cell killing effects of the microtubule inhibitor, stilbene 5c, against melanoma cancer. We utilized an in vitro murine melanoma model to study the effects of stilbene 5c on tumor proliferation and survival, as well as growth arrest and cell death. Our findings indicate that stilbene 5c promotes dose dependent cell death in melanomas with the induction of apoptosis and autophagy. The role of autophagy …

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Heat Shock Proteins As Novel Cancer Therapeutics: Targeting The Hallmarks Of Cancer, Chao Li Jun 2011

Heat Shock Proteins As Novel Cancer Therapeutics: Targeting The Hallmarks Of Cancer, Chao Li

Theses and Dissertations

Molecular chaperones, commonly known as heat shock proteins (HSPs), are essential for mammalian cells to maintain homeostasis, and HSPs function by inducing an ATPase-coupled structural change, followed by interactions with diverse co-chaperones and over 200 client proteins implicated in many critical signaling networks. These highly expressed HSPs participate in the onset and progression of several human diseases including cancer, and their connection with tumorigenesis has facilitated research and clinical trials related to targeting HSPs as a novel anti-tumor therapy. The predominant mechanism of chaperone inhibition is through either disruption of the HSP association with client protein or an altered binding …

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Examination Of Nak-Associated Protein-1 (Nap1) Homo And Hetero-Interactions In The Interferon Pathway”, Richard Call May 2011

Examination Of Nak-Associated Protein-1 (Nap1) Homo And Hetero-Interactions In The Interferon Pathway”, Richard Call

Theses and Dissertations

Double stranded RNA (dsRNA), the genomic material of some viruses and a replication intermediate in others, is recognized by multiple signaling receptors that initiate the anti-viral response1. Viruses have developed mechanisms to circumvent the anti-viral response by targeting components of the signaling pathway. An example of one such pathway is the TLR3 signaling pathway, which contains a kinase complex that activates interferon regulatory factor 3 (IRF3), leading to production of type I interferons. The kinase complex consists of a scaffold protein, NAK-associated protein 1 (NAP1), and two kinases, TANK-binding kinase 1 (TBK-1) and IκB kinase epsilon (IKKε). A fourty residue …

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Enhancing Family Functioning To Buffer Risk During Middle School Transition: Development Of The Multiple Family Group Weekend Retreat., Robert Broce May 2011

Enhancing Family Functioning To Buffer Risk During Middle School Transition: Development Of The Multiple Family Group Weekend Retreat., Robert Broce

Theses and Dissertations

Children experience changes in multiple levels of their social ecologies when they transition into middle school (Eccles, 1999; Jozefowicz-Simbeni, 2008). These biological, psychological, social, and environmental changes create increased risk for dropout and other factors related to academic adjustment (Cataldi, Laird & KewalRamani, 2009). For low- income minority children these risks can be magnified by environmental and social factors (Ge et al., 2002). Healthy family functioning, including balanced levels of cohesion and flexibility, has been shown to buffer these risks (Burchinal, Roberts, Zeisel & Rowley, 2008; Olson, 2010; Wampler, Munsch, & Adams, 2002) and was targeted by a Multiple Family …

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Model-Guided Systems Metabolic Engineering Of Clostridium Thermocellum, Christopher Gowen May 2011

Model-Guided Systems Metabolic Engineering Of Clostridium Thermocellum, Christopher Gowen

Theses and Dissertations

Metabolic engineering of microorganisms for chemical production involves the coordination of regulatory, kinetic, and thermodynamic parameters within the context of the entire network, as well as the careful allocation of energetic and structural resources such as ATP, redox potential, and amino acids. The exponential progression of “omics” technologies over the past few decades has transformed our ability to understand these network interactions by generating enormous amounts of data about cell behavior. The great challenge of the new biological era is in processing, integrating, and rationally interpreting all of this information, leading to testable hypotheses. In silico metabolic reconstructions are versatile …

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Quick Xlthlx Fish, Andrew Brehm May 2011

Quick Xlthlx Fish, Andrew Brehm

Theses and Dissertations

A sequence of short stories both fact and fiction leading to, resulting from, or having nothing to do with the three sculptures that comprise The Crescent Club, an installation for the Anderson Gallery.

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Synthesis Of Nanocomposites By Laser Ablation, Stephen Mutisya May 2011

Synthesis Of Nanocomposites By Laser Ablation, Stephen Mutisya

Theses and Dissertations

Immunoglobulin E (IgE)-conjugated gold nanoparticles were produced via in situ conjugation of gold nanoparticles with immunoglobulin E by laser ablation of Au in a liquid solution. The colloidal stability and the size distribution of the resulting bio-nanoconjugates were examined with UV-Visible spectroscopy (UV-Vis), dynamic light scattering (DLS), and transmission electron microscopy (TEM). These techniques showed that the Au nanoparticles in aqueous solutions were highly monodispersed spherical particles with a very narrow size distribution. The particles net diameter using TEM, was found to be D5 =3.8±0.9nm and D10 =4.7±1.3nm while the hydrodynamic diameter obtained with DLS was found to be h5 …

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Parent-Child Communication About Substance Use: Experiences Of Latino Emerging Adults, Kathryn Reid-Quiñones May 2011

Parent-Child Communication About Substance Use: Experiences Of Latino Emerging Adults, Kathryn Reid-Quiñones

Theses and Dissertations

The purpose of the current studies was to identify messages that Latino parents communicate to their offspring about the use of legal and illegal drugs and to determine associations between parental messages and substance use outcomes. Previous research has identified parent-child communication as protective against tobacco, alcohol, and other drug use. However, most of these studies have failed to examine the specific messages communicated and those that have focused almost exclusively on non-Hispanic Caucasians. Study 1 identified messages that Latino parents communicate to their offspring regarding legal and illegal drugs through two focus groups with Latino college students (N = …

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Plex, Jon-Phillip Sheridan May 2011

Plex, Jon-Phillip Sheridan

Theses and Dissertations

This thesis explores the evolution of my practice as it developed over my two years of graduate school. I entered school interested in the built environment and how structures helped create subjectivity and provided sites for material and phenomenological transformations. Early in graduate school, I developed a photography series that investigated these issues. However, an awareness of a conversation occurring in the larger art world that questioned the efficacy of photography drove me to consider ways to extend my practice into sculpture and installation. Over the next two semesters, I developed my ideas of light, form and structure into video …

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Meeting Sanford Meisner: An Investigation Of The Origins, Development, And Practical Application Of The Meisner Technique, Mandy Butler May 2011

Meeting Sanford Meisner: An Investigation Of The Origins, Development, And Practical Application Of The Meisner Technique, Mandy Butler

Theses and Dissertations

The Sanford Meisner Technique is among the most mysterious and misunderstood approaches to the craft of acting. Very often, it is taught poorly, incompletely, or even dangerously. Through the exploration of Meisner’s private life, as well as a detailed analysis of his system, this work aims to dispel some of the common misconceptions which plague the Technique and its most fervent supporters. After being made privy to his biography, readers will be taken through Meisner’s foundational exercises, beginning at the first phase of Repetition and ending with the introduction of text. In addition to the descriptions of student responsibilities, the …

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