STUDENT ABSTRACTS

Redshift surveys performed in the last two decades have shown the existence of large-scale galactic structures in the universe. To explain these structures, cosmologists numerically model the evolution of structure formation. Observational evidence gathered in the last five years indicates that our universe is accelerating due to a repulsive force, the cosmological constant, Λ. Previous numerical simulations have either not included Λ at all or considered it only as a factor changing the scalelength of the universe and not as a force which affects structure formation. This thesis presents a mathematical model for a universe containing Λ and the numerical simulation of 323 gravitationally interacting particles forming large-scale structure in a universe dominated by the cosmological constant.

We follow up on two types of observations made at the total solar eclipses in 1998 and 1999. The first observation seeks to generate a complete picture of the solar corona, typically difficult because of the corona’s large dynamic range, and coordinate it with space-based observations. We mosaic several exposures of varying lengths to make a complete picture. Repairing damage to the 1998 data resulting from a stuck bit, we are able to generate images for 1998 and 1999. We absolutely calibrate the 1999 data and use the 1998 data to obtain a rough measurement of scattered light in the SOHO C1 coronagraph. The 1999 data is coordinated with SOHO C2 and EIT observations taken during the eclipse to create a complete picture of the corona, from solar surface to 6 solar-radii. The second observation, described by Russell (2000), looks for intensity oscillations in bright coronal loops. These oscillations are associated with magnetohydrodynamic waves that may be responsible for coronal heating. We model the data in support of Russell’s measurements, which suggested the presence of oscillations in the 1 Hz range. Our models include a no-effect model to test noise induced by shifting in our image sequence and a test of our sensitivity to signals non-uniform in phase and spatial distribution. Sensitivity to oscillations down to 1% of total coronal intensity is confirmed.

In this thesis, I discuss the possible shapes for a flat universe. Recent observations suggest that the geometry of the universe may be flat. If this is the case, then there are only eighteen distinct possible topologies for the universe. Each of the eighteen Euclidean manifolds is classified and discussed here. The final chapter offers the possibility of observing the shape of the universe by analyzing the power spectrum of the spatial distribution of gamma ray bursts from the BATSE catalogue.

I present results from recent topside ionospheric research at the Arecibo Observatory in Puerto Rico. Aeronomers at the observatory have been collecting topside incoherent scatter data for more than a decade. We gathered and processed large portions of this data from throughout this period and began to make comparisons with a widely used model of the Earth’s ionosphere: the International Reference Ionosphere (IRI). Our results highlight significant discrepancies between our observations and the IRI predictions. Many of these differences may be aggravated by IRI’s overestimation of the electron density that recent studies have demonstrated, but accounting for this we still found areas where adjustments are needed. Particular areas of estimation errors included the light ion densities and fractions in the topside region.

BIOLOGY

Retinal ganglion cells (RGCs) are interneurons that convey visual information from the retina to the brain. Upon injury in fish and amphibians, these RGCs have the ability to regenerate to appropriate targets in the tectum, allowing the return of function. Retinal ganglion cells have also been observed to regenerate to a foreign target. In fact, when regenerating RGCs are redirected to a muscle by means of a peripheral nerve bridge, they extend over the muscle and form what appear to be synapses. In the present study, the objective is to test whether these regenerating neurons can form functional synapses to a foreign muscle target. RGCs were directed to the superior oblique muscle of the eye using an axotomized segment of the posterior lateral line nerve. The retina was stimulated approximately 80-100 days post-operatively with a light stimulus that is known to activate central nervous system neurons. EMG electrodes were placed on the muscle to monitor potential responses. No responses have been observed with the flash stimulus. Additionally, upon direct local stimulation of the retinal ganglion cells alone at the base of the optic nerve, no response was recorded from the superior oblique muscle. These results indicate that functional synapses may not be formed and challenges the hypothesis that a glutamatergic neuron (RGC) can form a true functional synapse with a normally cholinergically innervated muscle in the adult vertebrate.

We used a long-term mapping strategy to monitor S. nodosa life-history patterns, and found that plants have a high rate of survivorship from year to year once they grow beyond the seedling stage. Most S. nodosa plants grow vegetatively until they first flower, then they remain reproductive. In the field, we observed individually marked flowers and hand-pollinated flower stigmas to determine the stages and timing of flowering and the rates of pollen tube growth for cross- and self-pollen. S. nodosa is protandrous with little overlap between the pollen presentation and stigma receptivity. There is a slight but distinct advantage for cross-pollen in pollen tube development. Cross-pollinated flowers develop to a pollination stage later than or equal to that of their self-pollinated partners for all treatment times (2.5-45 minutes). Growth of more than one pollen tube from each pollen grain and attachment to lower sections of the stigma may give pollen grains an advantage in pollen tube competition.

Cell cycle regulation in eukaryotes is an extremely complex process involving myriad proteins that must function appropriately for the maintenance of normal growth. In the budding yeast Saccharomyces cerevisiae, cell division cycle (Cdc) proteins are among the key players that control cell growth. Certain mutations of one of these critical genes, CDC14, result in temperature sensitivity such that cells arrest at high temperatures and fail to exit from mitosis; consequently, normal growth is compromised. However, a mutation of the gene SFP1 has been found to suppress this temperature sensitivity and restore normal growth of cdc14 mutants at the otherwise non-permissive temperature. Furthermore, SFP1 has recently been implicated in the G2/M DNA damage checkpoint and thus is a gene with several functions vital for proper growth. Xu & Norris (1998) found that sfp1D mutants in the W303-1A background are more sensitive to MMS and fail to arrest normally at the G2/M checkpoint after DNA damage. Both observations were confirmed in these experiments for the sfp1D, sfp1-1, and sfp1-2 mutants in the A364A background strain. It was apparent that the sfp1 mutants differed from the wild-type SFP1 strain in sensitivity to MMS and functionality of G2/M arrest; however, whether the responses of the mutants differed significantly from each other remains unclear. Though SFP1 is a nonessential gene, its established multiple roles within the cell cycle compounded with the sickly phenotype of sfp1 mutants were the basis for preparing a synthetic lethal screen. A color-sectoring assay exploiting the adenine synthesis pathway could identify other genes whose mutants require SFP1 for survival. The appropriate SFP1 ADE3 plasmid and sfp1-1 ade2 ade3 strain necessary for the screen were constructed. Once the plasmid from E. coli is transformed into the S. cerevisiae strain, the synthetic lethal screen can be performed.

We have completed the characterization of the expression of a hunchback homologue in a basal annelid. In Drosophila melanogaster, the hunchback (hb) gene encodes a transcription factor involved in the earliest stages of segmentation and anteroposterior pattern formation. In the leech Helobdella triserialis, the hb homologue Lzf2 (Leech Zinc Finger 2) is expressed during development but shows no apparent AP function. Previous work with the basal polychaete Capitella capitata had partially determined expression patterns of a hb homologue, Cc-hb (Capitella capitata hunchback) during early cleavage. We created a staging system for Capitella development through metamorphosis, and determined that Cc-hb protein expression patterns closely resemble LZF2 expression patterns during all cleavage and organogenesis stages. We also attempted the first cloning of a potential homologue to the Drosophila caudal (cad) gene in annelids. Drosophila cad is a homeobox gene encoding a transcription factor, and acts as a posterior segmental organizer. Attempts at cloning cad from leech and Capitella via PCR with degenerate primers were successful only in obtaining a clone of the leech Lox7 gene. This result provides important information about the PCR technique and degenerate primer design.

Vessels are a dispersal vector for transporting marine organisms. This study examined the role of small coastal vessels in estuarine environments in mediating such dispersal, the first such study undertaken on the Atlantic coast of North America. A sample of 37 vessels based in Long Island Sound at Stonington, CT, revealed a heterogeneous assemblage of nearly 50 species of epibenthic (fouling) organisms, despite most of the vessels being coated with toxic, ablative antifouling paints. These taxa utilized a diverse array of microhabitats on a vessel's hull, such as the propeller and propeller shaft, the keel bottom, the rudder, and a variety of smaller intakes, holes, and crevices, including areas where paint had been worn away. Some of the taxa, such as the bryozoans and ascidians, lack a planktonic dispersal stage. Therefore, vessel-mediated dispersal may play a significant role in overall dispersal. It also may influence gene flow for these organisms and many other taxa for which natural geographic barriers (such as Cape Cod) inhibit planktonic dispersal. These vessels may also be critical in the secondary, coast-wise dispersal of non-native species after they have been initially introduced to the coast. An additional smaller sample of foreign vessels that had arrived in New London, CT (for OpSail 2000) after a short stay in the freshwater port of Philadelphia, PA, suggests that passing a ship through freshwater is not a completely effective means to reduce the transport of marine or estuarine species. Preliminary experiments on the “port renewal hypothesis,” which proposes that organisms transported across oligotrophic oceans may experience physiological renewal once reexposed to nutrient-rich coastal environments, suggest that the ascidian Botrylloides violaceus can survive the time required for an oceanic crossing without food, and that once food is renewed, live a considerable length of time thereafter, sufficient to potentially eventually undergo reproduction. All of these studies call into question the naturalness of the current distribution of many nearshore marine species around the world after more than five centuries of coastal/oceanic exchange.

CDC14, a cell cycle gene that acts in exit-from-mitosis, encodes a protein that is highly conserved between yeast and humans (Li et al. 2000). Several mechanisms of regulation of CDC14 action have recently become clear. The gene SFP1 appears to be one regulator of CDC14 (Paliulis et al. unpublished). sfp1 mutants suppress the temperature-sensitivity of many, but not all, cdc14ts alleles (Paliulis et al. unpublished). To better understand the reason why some alleles are suppressed well and others are not suppressed at all, two alleles of cdc14ts were sequenced. The results showed that cdc14-4 has two amino acid changes in the 3’ end of the protein and that the 5’ regulatory regions of both cdc14-1 and cdc14-4 cause temperature-sensitivity. Mutations in the 5’ regulatory sequence are more than 613 base pairs away from the START codon for CDC14, but have not yet been identified. To be able to put the results of the cdc14-4 mutation in context, crosses were performed to characterize the suppression phenotype of cdc14-4/sfp1 double mutants; suppression by sfp1 can be categorized as good.

The predominant free sphingoid long-chain bases in corn shoots and other plant tissues are sphinganine and 4-hydroxysphinganine. While sphinganine is the product of the first two steps in the biosynthetic pathway, the origin of free hydroxysphinganine has been questioned. We have demonstrated the direct hydroxylation of sphinganine to form hydroxysphinganine in corn microsomes. Sphinganine hydroxylase activity was assayed by monitoring the formation of hydroxysphinganine using standard HPLC analyses of fluorescent OPA derivatives. Hydroxylase activity required sphinganine and either NADPH (Km of 31 mM) or NADH and was localized to the endoplasmic reticulum. Dihydroceramide appeared to serve as a substrate for hydroxylation, but competition studies revealed that the hydroxylation of dihydroceramide occurred by means of an enzyme other than sphinganine hydroxylase. Following a 48-hr exposure to the mycotoxin fumonisin B1, an inhibitor of ceramide synthesis, the levels of sphinganine and hydroxysphinganine in corn shoot tips increased 3- to 7-fold and 8- to 10-fold, respectively, compared to controls. The direct addition of fumonisin into the in vitro assay did not affect hydroxylase activity; however, microsomes isolated from corn shoots treated with 1 µM fumonisin for 24 or 48 hr exhibited 5- to 7-fold and 8- to 11-fold increases in sphinganine hydroxylase activity, respectively. Treatment with 1 mM sphinganine for 48 hours increased the free sphinganine content in the corn tissue 3- to 4-fold compared to controls, but did not affect sphinganine hydroxylase activity. These results indicate that fumonisin upregulates the activity of sphinganine hydroxylase through an unknown mechanism.

CHEMISTRY

Interleukin-4 (IL-4) is a cytokine secreted by only TH2 and mast cells in response to a number of extracellular signals. The regulation of IL-4 provides a good system to study transcriptional regulation due to the tight control and inducibility of this process. Mast cells can be stimulated to produce the cytokine by the addition of ionomycin, a calcium ionophore, which bypasses the normal extracellular signaling requirements. Previous studies have identified a negative regulatory element, NEG-1 (-326 to -302), in the promoter region of the IL-4 gene. A complex of one or more proteins has been found to specifically bind this sequence. Interestingly, protein extracts from cells stimulated with ionomycin show an increased level of binding to the NEG-1 sequence. In this study, an investigation was performed to determine the molecular weight of the binding protein(s) using both crosslinking and gel filtration chromatography analysis. Mechanistic studies were performed using cycloheximide and Actinomycin D to determine whether translation and/or transcription of new protein could account for the increased binding observed with crude nuclear extracts from stimulated cells. The results of these studies indicate that a single protein of approximately 49 kDa binds specifically to NEG-1 in vitro. In addition, it was concluded that new transcription and translation may account for the increased binding observed with crude nuclear extracts isolated from cells stimulated to produce IL-4.

OH and CH oscillators are of great atmospheric importance; OH oscillators in terms of the OH cycle, and CH oscillators in terms of their global warming potential. The OH overtone transition energies and intensities for pernitric acid, nitric acid, nitrous acid, sulfuric acid, sulfurous acid, hydrogen peroxide, water, formic acid, methanol, ethanol(trans), ethanol(gauche), hypochlorous acid and hypobromous acid were calculated. Calculations were performed at the B3LYP/6-311++G(2d,2p) level of theory to obtain geometry optimizations. The same level of theory was also used to calculate dipole moment functions to the 5th order with ab initio, scaled ab initio (using the scaling factor base of experimentally observed water ω and ωx), and experimental anharmonic local mode parameters. The CH overtone transition energies and intensities for 1,1,1,2,3,3,3-heptafluoropropane, 1,1,1,2,2,3,3-heptafluoropropane, pentafluoroethane, and trifluoromethane were calculated in a similar manner except that the scaled ab initio scaling factor was derived from experimentally observed trifluoromethane ω and ωx. These calculations were compared to experimental values where possible and seen to give results that were comparable to the present level of experimental uncertainty.

The CH overtone spectrum of 1,1,1,2,3,3,3-heptafluoropropane was observed in the range of 800 to 2500 nm. Integrated intensities and oscillator strengths of this compound were measured for the first, second and third overtone. The oscillator strengths of these transitions were 6 x 10-8, 5 x 10-9 and 7 x 10-10 for the first through third overtones respectively. These were similar to other experimental values and also to the computationally predicted values of 7 x 10-8, 7 x 10-9, and 4 x 10-10.

(+)-Pacifigorgiol is a naturally occurring sesquiterpenoid that can be isolated from the pacific soft coral Pacifigorgia adamsii. It has demonstrated toxicity towards damselfish in bioassays, resulting in the conjecture that the coral releases it as a chemical defense against herbivorous fish. (+)-Pacifigorgiol is an intriguing molecule from a structural standpoint. It contains five densely packed contiguous stereogenic centers within a relatively small fused bicyclic framework. These features make it an enticing challenge for synthetic chemists.

In this work, we propose a novel asymmetric route to either antipode of pacifigorgiol. Our synthetic route employs a transition metal–catalyst to achieve the bicyclic skeleton of the target molecule from an acyclic precursor in one step via an intramolecular [4 + 2] cycloaddition. This underutilized class of reactions can serve as a synthetic alternative to the thermal Diels-Alder cycloaddition, which can have some restrictive electronic requirements. Transition metal–catalysis proceeds through a multi-step mechanistic pathway, often avoiding the restrictive HOMO-LUMO gap requirements of the Diels-Alder cycloaddition while still maintaining diastereoselectivity.

Bacillus subtilis responds to DNA damage by inducing the SOS DNA repair genes, a set of coordinately controlled genes. Gene induction is controlled by LexA and RecA proteins, which are themselves products of SOS genes. LexA binds to a consensus sequence within the promoter region of every SOS gene. A BLAST search of the Bacillus subtilis genome sequence database using the consensus sequence identified a number of potential novel SOS genes. Gel mobility shift analysis confirmed that LexA binds to these genes. This work reports that gene expression profiling confirmed that all 18 putative SOS genes are indeed novel SOS genes and are induced in response to DNA damage by mitomycin C and ultraviolet light. Additionally, the expression levels of several other DNA repair genes were determined and parts of the overall genomic response during the DNA damage response to both types of DNA damage were analyzed.

The biochemistry of the alanine aminoacylation reaction is well understood in E. coli, and the model developed in this organism appears to hold for prokaryotes and the cytoplasmic and chloroplast alanine systems in eukaryotes. The mitochondrial tRNA, however, display substantial deviation from the aminoacylation recognition pattern established in E. coli. Two mitochondrial tRNAs with fundamentally different deviations from the E. coli alanine model are investigated. The first, from the roundworm C. elegans, contains the basic alanine identity elements in the tRNA acceptor stem, but the tRNA lacks a TΨC loop, a major structural element that may have an important role in stabilizing the aminoacylation reaction. Chimeric tRNAs which exchanged parts of the canonical E. coli alanine tRNA for pieces of the C. elegans mtRNAala were used to assay for the effect of the TΨC loop upon aminoacylation. None of these tRNA chimeras was aminoacylated (in contrast to E. coli wild type tRNA, which was readily aminoacylated), indicating that the loss of the TΨC loop had a profound effect upon the tRNA. This effect could be due to incorrect base pairing or a noncanonical tertiary structure; however, further experiments could not resolve this difference, and the lack of chimeric charging remains unexplained. The second system investigated is from human mitochondrial tRNAala. In this tRNA, the canonical cloverleaf tRNA structure is intact, but the alanine tRNA recognition elements known from E. coli are altered substantially. In order to investigate this system, the human mitochondrial AlaRS (HMA) was cloned from a cDNA library. The first cloning attempt did not generate active enzyme, which may have been due to the presence of a mitochondrial targeting sequence on the N-terminus of the protein. A second cloning attempt sought to remove this targeting sequence from the protein by selective PCR. SDS-PAGE analysis suggests that the HMA clones without the mitochondrial targeting sequence were well expressed in the E. coli expression system.

Incubations of groundwater collected from coastal marshes in Warwick and Kingston, RI, USA were carried out to determine the lability of dissolved organic carbon to the groundwater bacterial community. Groundwater was collected on six days between August and December 2000 from wells that had been installed at the two sites. The groundwater samples varied in distance from the water’s edge, depth below the ground’s surface, salinity, temperature, collection date, and initial concentrations of both dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) that they contained. The incubations were run at approximately 15 ˚C for different lengths of time ranging between 7 days and 37 days. Samples from different time points during the extent of the incubation were analyzed for DOC and DIC. Prior to incubation, some groundwater samples were filtered through 0.2 μm filters and some were not. The unfiltered groundwater tended to show a net increase in DOC with time, while the filtered groundwater either showed a net decrease in DOC or no significant change at all. Lability was determined by calculating the net loss of DOC as a result of the incubation. The small losses of DOC during the incubation suggested that the DOC in the filtered groundwater was not very active in bacterial respiration or denitrification processes. This finding contradicted ambient measurements, which suggested that DOC use in the groundwater was dynamic and affected denitrification capacity. That the unfiltered groundwater showed a net increase in DOC suggested that particulate organic carbon (POC) might be an important source of groundwater organic carbon. Future research will investigate the lability of DOC in the soil matrix where DOC sources and bacterial populations are more similar to ambient conditions.

Kava is an herbal remedy that originated as a ceremonial beverage in many Pacific Ocean societies. Although it exhibits a variety of physiological effects, such as the ability to relax muscle and to induce sleep, it is most touted for its anxiety-relieving properties and is increasingly being perceived as a viable alternative to synthetic anxiolytics like Valium. Of special biological interest is the fact that kava appears to relieve anxiety in a pathway that differs from the mechanism of action of benzodiazepines like Valium.

Although the potency of crude kava root extract greatly exceeds that of its individual component active principles – the kavalactones – certain molecules seem to specialize in certain biological abilities. For example, dihydromethysticin and dihydrokavain demonstrate analgesic properties at twice the potency of aspirin while kavain by itself seems to demonstrate a limited ability to relieve anxiety. Investigations into these pathways may yield important biological insights with regard to pain and anxiety pathways.

Development of an asymmetric synthesis that is both general and practical is possible given the structural similarities between the fifteen kavalactones – each kavalactone demonstrates one stereogenic center with the same absolute configuration as all the others, a lactone with a methyl enol ether moity, and a side chain. Access to enantiomerically pure samples of kavalactones and their unnatural analogs for study is an endeavor of increasing importance given the rising popularity of alternative medicine and the need for more information specifically concerning this compound.

Toxicariosides A, B, and C were isolated from the sap of the tree Antiaris toxicaria in the Richardson lab, at Williams College. The Richardson group then determined that the absolute stereochemistry of the aglycone moieties in these cardiac glycosides is identical to that in α-antiarin, a cardenolide previously isolated and characterized from the same natural source. The saccharides were determined to be: A: 6-deoxy-2-O-methylgalactose; B: 6-deoxy-2-O-methylglucose; C: 6-deoxy-2-O-methylgulose, however, the absolute configuration of these sugars could not be established. Studies were begun to develop a method to determine the absolute stereochemistry of the sugars of cardiac glycosides, whereby they were cleaved from the aglycone moiety, transformed with a chiral, optically active molecule, and the resulting diastereomers were analyzed by gas chromatography.

Upon cleavage from the aglycone, saccharides were butylated with optically pure 2-butanol and permethylated. In this thesis, final refinement of the analytical method was accomplished, and involved a significant reduction in substrate scale in order to simulate the synthetic transformation of the toxicariosides. Transetherification with S-2-butanol accomplished the cleavage, producing butylated saccharides that were subsequently permethylated. The method was developed on a very small scale and refined to produce unambiguous results on several cardiac glycosides before application to toxicariosides A, B, and C. In this study, the absolute stereochemistry of the saccharide moiety of toxicarioside A was determined to be D. The absolute stereochemistry of the saccharide carried by toxicarioside B was tentatively determined to be L, while the sugar of toxicarioside C was tentatively identified as D.

In recent years, the number of enzymes identified as zinc enzymes has increased dramatically. The zinc(II) ion in these enzymes has been proposed to serve a wide variety of catalytic functions, yet the mechanism of catalysis and role of the metal in many of these enzymes is not completely resolved. For this reason, small molecule synthetic models of an enzyme’s active site are useful in exploring the role of zinc and the ligands coordinated to it.

Progress has been made toward the synthesis of models that mimic the unique one histidine and two cysteine [NSS] coordination environment of Liver Alcohol Dehydrogenase and Methionine Synthase. Attempts at preparing an [NSS] ligand utilizing substituted oxazoles is described. The synthesis of one [NSS] ligand, N,N-bis(ethanethiol α,α dimethyl)2-methylthioethylamine, is described. This ligand reacts with nickel(II) and zinc(II) compounds to give complexes formulated as M[NSS]. Molecular orbital calculations have begun to explore whether the extensive methyl substitution in the ligand backbone favors the formation of monomeric products.

As jet aircraft fly across the sky, they leave behind them trails of small H₂SO₄-coated soot particles that serve as condensation nuclei for water droplets. These condensation trails, visible from the ground, have been observed to contain a greater percentage of sulfur in the form of H₂SO₄ than predicted by current models and engine ground tests. As a result, the H₂SO₄-coated soot particles themselves have been proposed to take part in a heterogeneous chemical reaction involved in converting SO₂ from the aircraft’s emissions into H₂SO₄. We have spent the year studying the effect of a monolayer-scale H₂SO₄ coating on the ability of SO₂ to adsorb to soot formed by the combustion of n-hexane.

Our experiments take place on a thin film of soot under simulated atmospheric conditions. To make sub-monolayer and thicker layers of H₂SO₄ on the soot, we first deposit SO₃, then excess H₂O, and then heat to -80°C. Bulk and sub-bulk SO₃ adsorption has been observed. We have discovered that at sub-bulk levels SO₃ penetrates deeply into the soot. The most efficient method of constructing H₂SO₄ has been by using SO₃ that has bound to the internal pores of individual soot spheres. Using this method, we have constructed H₂SO₄ layers of 1.4 to 2.7 monolayers (ML) thick (+50%). By using SO₃ bound to the surface of the soot particles, we have made layers as thin as 0.006 ML.

Because of their interesting physical properties and potential applications in commercial devices such as microprocessors, the synthesis and study of one-dimensional conducting materials has come into the fore of materials science. We have met the challenge with significant progress towards the synthesis of novel liquid crystalline bipyridine ligands capable of complexing to group VIII metals in order to form potentially conductive, one-dimensional metal chain systems. This paper focuses on the steps involved in the synthesis of 4,4’- and 5,5’- diamino 2,2’-bipyridines, both with and without 3,3’ methyl groups, condensed with two trialkoxy benzoic acids with variable length aliphatic substituents (C₆, C₈, C₁₀, C₁₂, C₁₄, C₁₆). The characterization of an analogue of our 5,5’ target ligand indicates the presence of a mesogenic phase.

COMPUTER SCIENCE

With the disparity between processor speeds and memory speeds growing, caches have become crucial to the performance of modern computers. Simultaneously, developers are trying to use the Java platform for more than spinning pretty pictures in web pages. Due to the platform’s architecture, a JVM implemented in software is unable to make use of the instruction cache on the underlying machine. We will first look at the distribution of memory accesses made by an executing Java program, and then compare the impact of caching for a Java program versus a traditional natively compiled program. We will end by considering alternative cache configurations, including a dedicated stack cache, and by discussing what work remains to be done.

The Java programming language incorporates several concepts from the academic research community. An intermediate compilation language (which makes platform independence possible), and automatic garbage collection have both contributed to Java's recent success. However, Java’s type system lacks support for important features found in many modern programming languages. These features include parametric polymorphism, and (less commonly) ThisType. Since Java lacks a robust type system, programmers are often forced to abandon static type safety and resort to risky run-time checks.

Several projects in the recent past have extended Java with more expressive type systems while still targeting the standard Java platform. In this project, we extend on one such language, Rupiah, by improving its implementation of parametric polymorphism and adding a new kind of constructor, ThisClass – a robust mechanism for virtual object creation. We begin this talk by providing some motivation for including these new constructs in the language. Then we describe their implementation and advantages when compared with programs written standard Java. Finally, we suggest several ideas for implementing the language more elegantly and efficiently in the future.

GEOSCIENCES

An evaluation of the hydrogeologic resources of the Arlington 7.5 minute quadrangle, VT, was carried out for the Vermont Geological Survey under a contract with the Vermont Geology Division. The extent of carbonate bedrock and glacial overburden surface aquifers in the valley portion of the quadrangle was delineated. Maps of overburden thickness, piezometric surface, and aquifer recharge potential were generated, as were four stratigraphic cross sections across the quadrangle.

One thousand ninety-three water well drill logs were initially examined from computerized records obtained from the Vermont Survey. Of these, 328 wells could be confidently correlated to existing homes and placed on a map using ArcView. The quadrangle’s primary groundwater source is a large confined carbonate bedrock aquifer. The aquifer underlies all inhabited portions of the quadrangle; its extent is revealed by subsurface data from 213 wells. A piezometric surface map for this aquifer was constructed and indicates that areas surrounding topographic highs where there are gaps or thinning in the confining layer might have an enhanced aquifer recharge potential. Several smaller unconfined surface overburden aquifers exist in kamic fields throughout the Vermont Valley. The smaller aquifers currently play a secondary role as groundwater resources for the quadrangle, but could potentially become more important as water demands increase.

Glacial advances and retreats, prominent factors in global climate and sea level change, are controlled by climate and a combination of processes including ice deformation, basal sliding, and subglacial hydraulic systems. Evidence of the effects of these processes is preserved in the landforms and deposits left behind. Examining deposits recently uncovered by retreating glaciers is one method of studying subglacial processes and glacier sliding. Features of subglacial deposits, including their distribution, morphology, and chemistry, provide specific clues about the interaction of ice, the bedrock it flows over, and subglacial water. Morphology of subglacial deposits is a key to understanding the larger aspects of glacier systems, and how they, in turn, have affected global climate throughout Earth history.

In the past two decades, the retreating Mendenhall Glacier in Juneau, Alaska has exposed a bedrock ridge spotted with patchy coatings of calcite-cemented clay to sand-sized lithic grains. These coatings, referred to in this study as 'silt skins', range from 0.5 to 20 mm in thickness and display two distinct morphologies: striated and corrugated. Striated silt skins are thin, located mainly on stoss slopes, and preserve local striation direction. Thicker, corrugated skins form on lee slopes and consist of parallel microridges elongated in the local downslope direction.

Deposition of silt skins at the Mendenhall Glacier depended on macro-scale processes in the glacier system, outcrop-scale features of the rock ridge, and micro-scale interactions of the ice, bedrock, and thin films of water in the regelation layer. Calcite in silt skins probably originated from the weathering of feldspar, and became concentrated in basal ice through glaciohydraulic supercooling. Isotopic values of d 018 and d C13 with respect to the PD Belemnite standard indicate that skins were deposited in subglacial waters with varying isotopic concentrations, and that the carbon in silt skins is derived from inorganic sources.

Corrugations are depositional features enhanced by erosional processes; wavelengths generally range from 1 to 10 mm. They formed as sediment-rich water dripped or oozed down lee slope rock faces. Erosional and deformational effects on silt skins may have caused surficial chemical compositional differences of Ca/Si in skins and the oversteepening of internal microlaminae. Secondary deposition and erosion on wavy laminae may enhance the appearance of truncations in thin section, in addition to controlling crest morphology and wavelength. Silt skins probably formed when a subglacial cavity system was active on the rock ridge, probably within the last 60 years. Specific features of the cavity system, whether it was autonomous or interconnected, and features of local valleys that preserve an abundance of silt skins, are clues as to how micro-scale processes interact with larger-scale subglacial systems. Silt skins are evidence that the subglacial environment is complex, dynamic, and responsive to changes experienced by the whole of the glacier system.

Samples for U-Pb zircon SHRIMP geochronology were collected from the western extent of the Itremo Group Proterozoic metasediments in central Madagascar during August 2000. Zircons with rounded detrital cores with truncation of internal zoning are interpreted to represent transported grains and are present in metasediments. Euhedral, zoned cores with no evidence of mechanical weathering are interpreted to represent non-transported zircon grains from igneous and meta-igneous rocks. Metamorphic zircon overgrowths occurred on grains from all samples analyzed. When possible, core-rim pairs were analyzed on both detrital and igneous cores. The Itremo Group was previously determined to have been deposited between 1722±40 Ma (youngest detrital zircon [Chokel, 2000 #39]) and 791 Ma (age of oldest intrusion in Itremo Group [Handke, 1999 #6]). This study does not improve the resolution of this depositional interval. However, sample MAD 00-36 may represent basement to the Itremo Group, which has not previously been found or dated.

Concordant detrital core ages from one group of metasediments in this study cluster at 980 Ma, 850 Ma, ~800-750 Ma, and ~650-600 Ma. Therefore these sediments are tentatively interpreted to be a separate Neoproterozoic-derived sedimentary sequence, here named the Molo River Sequence. Comparison of detrital core ages from this study with a database of crystalline basement rock ages from various Rodinia/Gondwana cratons (provenance analysis) suggests that the Itremo Group is derived from a combination of south Indian, Sri Lankan and Malagasy source rocks, and that East Antarctica can be excluded as a source area. Provenance analysis also suggests that the Molo River Sequence is derived from East African crystalline basement rock.

Both the Itremo Group and the Molo River Sequence have metamorphic overgrowths dated to ~550 Ma. This tectonothermal event is the signature of the final amalgamation of Gondwana. Three-dimensional analysis of the Lazarivo SPOT scene suggests that this modeling technique will be useful in the analysis of the complex structural geology associated with this continental collision. However, Arcview comparison of the contour lines derived from the 100 km pixel DEM and actual topographic map contours shows that a higher resolution DEM will be required in order to do detailed structural analysis.

In the last ten to thirty years, retreat at the Mendenhall Glacier has revealed a bedrock ridge with significant evidence for deflection of flow on both the macro and outcrop scale as the glacier encountered the stoss and lee feature. The schist ridge or “rib” at the Mendenhall abuts the valley wall at an 82-degree angle, thus presenting an obstacle to glacier flow for much of the valley that deflected flow. The stoss face of this rib consists of a series of stoss and lee features stepping up to the ridge crest. The relatively unweathered surface of the large-scale stoss face affords an excellent opportunity to study the effects of the bedrock obstacle on flow patterns, both on an outcrop and a macro scale. These striations reveal a pattern of deflected and undeflected striations on both scales.

The City of Rocks dome, near Almo, Idaho, is part of a chain of metamorphic core complexes extending from southern Canada to northern Mexico. The 29 Ma Almo pluton intruded ~2.5 Ga granitoids and unconformably overlying metasediments. Exposures of the Almo pluton in the City of Rocks National Reserve and Castle Rocks consist of large outcrops in the forms of fins, bornhardts and tors. The rocks of the City of Rocks dome are extensively jointed. Joints can be found in all orientations, but there are two sets of steeply-dipping joints that are pervasive through the unit and are more prominent than random distribution would allow – one striking WNW-ESE and the other striking N-S. These joint sets are attributable to Miocene extension and doming events. Analysis using Geographic Information Systems (GIS) supports the theory that shallowly-dipping joints are the result of unloading and also demonstrates a relationship between the N-S joint set and the overall slope direction of the basin.

Stream terraces along channels of the Birch Brook catchment probably record response to increased sediment load resulting from land clearing throughout the 19th century. There are three main terrace levels along Birch Brook that I differentiate on the basis of height above the channel: low (<1.1 m above channel), intermediate (1.1 m – 2.0 m above channel), and high (>2.0 m above channel). The low, youngest terraces are the focus of this study.

Sediment budgets for the South Branch of Birch Brook catchment, NW Massachusetts, indicate that annual bedload discharge (~2.0 tons km-2 yr-1) is a function of the number of peak events above bankfull (0.34 m3 s-1) and sediment supply. Sediment availability in the South Branch, a small, forested mountain stream draining 1.25 km2, is limited due to low erosion rates on hill slopes. Significant sediment storage occurs behind organic debris dams, and in pools associated with bedrock reaches. When annual storm events are < 80 to 90 percent of bankfull, relatively little sediment is available for transport. Because sediment storage along the channel is substantial, the relationship between discharge and sediment delivery shifts after high discharge events, such as the 15-year flood, which flushes out significant debris dams and transports sediment downstream.

The bedrock channel of the South Branch is typical of upper stream reaches within Birch Brook; lower reaches are alluvial. Bedrock reaches are sediment starved, with steep stream gradients ~0.08, narrow channel widths of ~2 m, low sediment supply, and high sediment transport capacity, though the lack of readily available sediment limits the amount of sediment transported. Alluvial reaches are 2 m wider, have stream gradients much lower than 0.06, and a higher sediment supply than upper bedrock reaches. The sediment available in these reaches is stored in low terraces, gravel bars, and in the channel bed. Mean annual sediment load for Birch Brook is between 2.0 and 4.0 tons km-2 yr-1.

Deforestation, grazing and cultivation within the Birch Brook catchment throughout the 19th century produced increased erosion on hill slopes and stream aggradation. The total volume of sediment associated with the formation and incision of low terraces is ~9,000 tons. Based on STELLATM models for sedimentation within Birch Brook during the 19th century, hill slope erosion probably reached values of 40 - 70 tons km-2 yr-1 during disturbance, building low fill terraces despite increases in sediment yield. Tree core ages show that terraces stabilized between 60-80 years before present, after the terraces had sufficiently incised to leave terraces isolated from the effects of annual flood discharges.

MATHEMATICS

There are three components to this study – the first, a historical and analytical survey of the calculus; the second, a comparison of teaching methods and approaches across two cultures, the United States and Jamaica; the third, a section on course module development. In the history of the calculus, we examine how calculus developed, the motivation of the theory and the major problems encountered. We present an overview of contributions by early mathematicians, a more in-depth look at the work of Newton and Leibniz, and discussed how calculus was made rigorous in the 1800s.

Rank one transformations are a class of ergodic transformations constructed using a cutting and stacking method. We show that a class of rank one transformations characterized by adding spacer levels that have restricted growth but also tending toward a uniform type of distribution are indeed mixing transformations. All previously known mixing rank one transformations, including staircase transformations satisfying the restricted growth condition, fall into our class.

PHYSICS

Polyacetylene is the simplest member of the family of conjugated polyenes, molecules possessing a carbon backbone with alternating single and double bonds. This group includes a number of molecules with interesting optical properties; by studying polyacetylene, we hope to gain a better understanding of conjugated polyenes as a whole. We theoretically examine the effects of applying a mechanical stretch to polyacetylene chains on the photoexcitation gap of these chains. Calculations are performed using two different models: the Su-Schrieffer-Heeger (SSH) model for polyacetylene, and an extended Hubbard model that includes important electron correlations omitted by the SSH model. Stretching is shown to have a color tuning effect on polyacetylene chains. The details of this effect are explored in a variety of contexts - with correlated vs. uncorrelated models, in even vs. odd length chains, and finally in undoped vs. doped chains.

After reviewing the background needed to discuss the problem, we explore entanglement sharing among three qutrits (spin-1 particles), and among objects with greater spin. We find a lower bound for “optimal” entanglement sharing among three qutrits, and speculate about entanglement sharing among objects with N orthogonal states, investigating N = 4 and N = 7 in particular. Our work is an attempt to extend the results of Coffman, Kundu, and Wootters [3], who extensively studied entanglement sharing among three qubits (spin-1/2 particles).

This thesis describes an ongoing experiment, the goal of which is to measure the Stark shift in the 6P_1/2 → 7S_1/2 transition in atomic thallium. An accurate Stark shift measurement provides a sensitive test of wavefunction calculations essential for the interpretation of atomic parity non-conservation experiments. A description of the equipment and its operation, including a frequency-doubled and stabilized laser, an atomic beam apparatus, and a precisely calibrated high voltage electric field system, will be given. Our preliminary measurement of the Stark shift constant of proportionality of: 119(4) kHz/(kV/cm)2 is in agreement with previously measured values. Once we resolve systematic experimental errors, which are discussed here at length, we expect to complete a measurement with uncertainty below the $\pm 1\%$ level.

There exists for the quantum mechanical phenomenon of entanglement a good mathematical quantification called concurrence. Due to the growing investment in the properties of entangled systems, one would hope to find a physically interpretable measure of entanglement that one could access more directly in the lab. In this thesis we investigate various measures of “outcome-entropy” - these measures express one’s degree of ignorance about the outcome of a measurement for two-qubit systems with varying values of the concurrence. (A qubit is any binary quantum object). By comparing the concurrence of a system to its outcome-entropy we found two particular measures, the average Bell outcome-entropy and the minimum linear outcome-entropy, which exhibited a notable correlation. The latter also displayed a lower bound on the amount of concurrence possible for any two-qubit system with a certain outcome-entropy. We present these findings in the following pages and conclude by discussing potentially better correlations that might be obtained by considering other measures of outcome-entropy related to the ones studied in the thesis.

We follow up on two types of observations made at the total solar eclipses in 1998 and 1999. The first observation seeks to generate a complete picture of the solar corona, typically difficult because of the corona’s large dynamic range, and coordinate it with space-based observations. We mosaic several exposures of varying lengths to make a complete picture. Repairing damage to the 1998 data resulting from a stuck bit, we are able to generate images for 1998 and 1999. We absolutely calibrate the 1999 data and use the 1998 data to obtain a rough measurement of scattered light in the SOHO C1 coronagraph. The 1999 data is coordinated with SOHO C2 and EIT observations taken during the eclipse to create a complete picture of the corona, from solar surface to 6 solar-radii. The second observation described by Russell (2000), looks for intensity oscillations in bright coronal loops. These oscillations are associated with magnetohydrodynamic waves that may be responsible for coronal heating. We model the data in support of Russell’s measurements, which suggested the presence of oscillations in the 1 Hz range. Our models include a no-effect model to test noise induced by shifting in our image sequence and a test of our sensitivity to signals non-uniform in phase and spatial distribution. Sensitivity to oscillations down to 1% of total coronal intensity is confirmed.

This is my senior thesis, discussing the possible shapes for a flat universe. Recent observations suggest that the geometry of the universe may be flat. If this is the case, then there are only eighteen distinct possible topologies for the universe. Each of the eighteen Euclidean manifolds is classified and discussed here. The final chapter offers the possibility of observing the shape of the universe by analyzing the power spectrum of the spatial distribution of gamma ray bursts from the BATSE catalogue.

PSYCHOLOGY

This study investigated the way in which Black Jamaican and White North American Kindergartners and 5th/6th Graders evaluate themselves and their peers based on Skin Color and Body Size. Black and White experimenters tested 262 Rural and Urban Jamaican children and 150 North American children using 5 measures: A Story Task, Playmate Preference Task, Self-Identification Task, Self-Esteem Task and a Skin Tone Assessment. Results revealed that both Jamaican and North American children stigmatize Black skin: stigmatism decreases with age in Urban Jamaican and North American children, but increases with age in Rural Jamaican children. As predicted, Rural Jamaican children favor chubbiness more than do Urban Jamaican children: stigmatism of chubbiness increases with age for Jamaican children. While both North American age groups show Body Size stigmatism, this decreases with age. Overweight North American, but not Jamaican, Kindergartners had low self-esteem. Important experimenter race effects on Jamaican children's self-identification and preference were found. Implications of these findings are discussed.

There has been much recent debate over the veracity of recovered memories. Some critics argue that it is possible to discover traumatic memories that have been repressed for long periods of time, while others attribute recovered memories to suggestion from outside sources such as therapy. I conducted two experiments to study whether it is possible to implant false memories into people’s minds through their own (apparent) testimonies. In the first study participants gave testimony about committing various indiscretions, some of which they actually had committed, and some of which they had not. The results of this study demonstrated that after giving testimony, and later watching tapes of their testimonies, a significant proportion of the participants accepted at least one of their false-testimony stories as true. In the second study participants gave testimony about various tasks they had performed during a party. A few months later, these participants saw clips of their testimonies on video, but for some of these participants these tapes were edited so that the meaning of their testimonies was changed, and thus they were exposed to essentially false testimonies about their behavior. The findings from this study indicated that as a result of giving testimony and watching manipulated video clips of their testimonies, a significant proportion of participants came to believe that they had committed odd or embarrassing acts that in reality they had not done. Implications for the recovered and false memory debate are discussed.

In the current study, 95 children of different peer social status classifications (rejected, neglected, average, and popular) were exposed to hypothetical vignettes and a rigged social rejection experience in order to assess their “on-line” appraisals of mild peer rejection. Five aspects of children’s appraisal were assessed, including angry and anxious expectations, locus of control, hostile attributions, and emotional distress. Social and emotional adjustment was assessed through peer-, parent-, and self-reports. Rejected girls showed more distress than any other group in response to the rigged rejection experience. As expected, sociometric rejection was associated with more negative adjustment outcomes across all informants. More importantly, appraisal variables emerged as significant predictors of adjustment above and beyond rejection, as well as significant moderators of the relationship between rejection and adjustment. Specifically, angry and anxious expectations of rejection resulted in a greater increase in parent-rated internalizing and externalizing problems among rejected children, and a greater increase in self-rated internalizing problems (e.g., social anxiety, low perceived competence) among non-rejected children.

The current research examined whether male undergraduate students would exhibit subtle but perceptible behaviors consistent with homophobia if they were put into a situation in which they were associated minimally with homosexuality, and if these reactions would be moderated by manipulations of their state self-esteem. The state self-esteem of male participants was either threatened, affirmed, or kept neutral through a questionnaire. The participants next were randomly assigned to wear a sticker with the word “queer” or a neutral word “quest” for an interaction with a male confederate. Just before the interaction, participants performed a lexical decision task, which measured their automatic activation of stereotypic attributes associated with homosexuals. They next interacted for several minutes with a male confederate, who was blind to the participants‚ conditions. Participants in the queer sticker condition sat significantly further away from the confederate during the interaction than did participants who wore a neutral sticker, but this difference was eliminated among participants who had been self-affirmed. Participants who wore the queer sticker also appeared to the male confederates to be more distressed and psychologically distant, even though the confederates in reality were blind to condition. The implications of these results, as well as suggestions for future research on this and related topics, are discussed.

The purpose of the present study was to examine the stories children construct about their friends. We were interested in characterizing the emergence and development of children's stories about other children's lives. That is, when asked to tell stories about their friends, what kinds of stories do children produce? We began looking at this phenomenon using a naturalistic approach and later a more structured one eliciting stories from children. Forty-three children between ages four and ten were interviewed. Potential age, gender, and experimenter effects were investigated. The results show that children provide three different kinds of biographical materials about their friends: simple descriptions (discrete pieces of information not in context of stories), scripts depicting routine events, and narratives documenting past or present experiences. The amount of discrete pieces of information increase with age and much of this increase can be attributed to an increase in intrapersonal and biographical details. The number of scripts and narratives about friends also increase with age. These stories become longer, more descriptive, include more evaluative comments, more other-focused, and more concentrated on the internal landscape of others. Children learned most of the stories from direct experiences, though with age, they also increasingly tell stories that they have heard from others. Scripts are found to be more impervious to developmental and experimenter effects. Furthermore, girls evaluate more and focus more on the internal landscape than boys do in their narratives. Finally, the interviewer is found to have a profound effect on the type and number of stories elicited about friends. Implications for such findings and directions for future research are discussed.

Studies have shown that self-presentation, the manner in which an individual portrays himself or herself in public (that is, in the presence of another) is one dimension on which individuals with an interdependent construal of self and individuals with an independent construal of self differ. Individuals with an interdependent construal see the self in relation to others; the group is the whole and the self is a member of that whole, and as a result tends to have a more modest presentation in order to be mindful of the feelings of the other. Individuals with an independent construal see the self as a whole, separate from all others, and as a result tend to have a presentation which emphasizes expressing themselves (a less modest presentation). There are also gender differences in the self-presentation of men and women such that women tend to be more modest than men as a result of their response to relational cues. The present study was done to discover currently unanswered questions regarding the presentation of Asian students, a population which may have been exposed and socialized in interdependent cultures, and Caucasian students, a population which may have been exposed and socialized in independent cultures, to discover what differences exist if any. Consistent results from the data showed among other things that Asian participants were more modest than Caucasian participants, that women were more modest than men, that Asian women were more modest than Asian men, and that the acculturation of Asian participants to Asian and American culture did have an effect on both their public and private report; the implications of which are discussed in the study.

This research was designed to examine how social influence factors can affect students' attitudes about racially sensitive issues, such as attitudes or policies that are often characterized as “politically correct” after exposure to derogatory humor. Study 1 used a survey conducted early and late in the academic year to assess the change of PC attitudes among white, black, and latino/a first-year students at a small liberal arts college. Black and white students became less likely to endorse PC attitudes over the course of the year, however latino/a respondents became significantly more likely to endorse PC attitudes. Study 2 examined the effects of a motivational factor-self-esteem threat, and a social influence factor-exposure to local norms about the acceptability of derogatory humor aimed at minorities and women, on white participants' responses and attitudes in a group setting. Participants' reactions to the humor conformed to the manipulation of group norms. Moreover, participants' whose self-esteem had been threatened were particularly affected by the manipulation of these norms on their PC attitudes, such as concerning affirmative action. Study 3 extended Study 2 by also examining the effects of the presence of minority students in the group setting. The presence of minorities in a group whose norm was clearly Anti-PC appeared to facilitate white participants, particularly those with relatively negative attitudes toward minorities, to express disapproval of PC policies such as affirmative action. In general, these results suggest that social influence, self-esteem threat, and group composition are all potentially important, and interactive, factors in affecting reactions to racially sensitive humor and policies.

This study aimed to test the influence of the word and concept bitch on women’s readiness to express themselves strongly. It was hypothesized that the threat of being judged a bitch induces women to inhibit their assertiveness and anger expression, and that when the salience of this threat was enhanced women would display less such expression than under neutral circumstances. One hundred thirty-four male and female participants completed a scrambled sentences task in which one of the following variations on the bitch construct was primed: (1) bitch-related trait words accompanied by female pronouns; (2) bitch-related trait words accompanied by male pronouns; (3) the word bitch itself; or (4) neutral words. Following this priming task, a male experimenter issued an anger manipulation by informing each participant that she would not receive course credit for participation. Participants’ responses were covertly videotaped and later coded for assertiveness, inhibition of assertion, and several forms of anger expression. Contrary to the hypothesis, the priming did not influence women’s expression. Surprisingly, however, male participants showed significantly less assertiveness in the female-trait, male-trait, and bitch conditions, as compared to the neutral condition. Males also showed markedly less vocal anger expression in the bitch condition than in any other condition.

This investigation used standardized personality and self-report measures of fantasy proneness and dissociation to determine which adult personality traits were related to having an imaginary companion (IC) in childhood. Participants were 164 college students who completed the California Personality Inventory (CPI), the Dissociative Experiences Scale (DES), the Inventory of Childhood Memories and Imaginings (ICMI), and a questionnaire and interview on childhood ICs. ICs were recalled by 24 percent of the participants and were found most frequently in only children. A logistic regression analysis revealed that five measures were predictive of having a childhood IC: Socialization, Communality, Self-Control, ICMI, and literary creativity. These results suggest significant differences in adult fantasy, creativity, and several modes of self-perception in society between those who did and did not have childhood ICs. They were discussed in light of previous findings which are characterized by a lack of agreement as to the extent that personality traits like sociability, dissociation, and creativity are related to having an IC.

STUDENT ABSTRACTS

Astrophysics

BIOLOGY

CHEMISTRY

COMPUTER SCIENCE

GEOSCIENCES

MATHEMATICS

PHYSICS

PSYCHOLOGY