Two Completely Independent Problems in Astrophysics: Radio Observations of Molecular Emission and Absorption Lines & The Internal Polarization of the Williams College Coronal Eclipse Equipment
Gabriel B. Brammer
The first section of this thesis discusses radio observations made with the Nobeyama Radio Observatory 45-m millimeter telescope and the Steward Observatory 12-m millimeter telescope to detect molecular emission lines. The observations are for three main projects: to determine the isotopic ratios of a variety of atoms (D/H, 12C/13C, and 14N/15N) in a sample of molecular clouds distributed throughout the Milky Way Galaxy to model galactic chemical evolution; to observe a variety of molecules in a cloud 28 kpc from the galactic center, thought to be representative of the material from which the Galaxy formed; and to observe deuterated molecules in galaxies at high-redshift to determine an estimate of the primordial D/H abundance of a few seconds after the Big Bang. The D/H abundance of the Milky Way can be used, with models of deuterium processing, as another method to determine the primordial D/H abundance, which can be used to determine the baryonic density of the universe. We present results of DCN detected in ten galactic sources and HC15N detected in nine of the ten sources. We conclude with a list of fifteen molecules detected in the cloud at the edge of the Galaxy, for which preliminary analysis indicates that this cloud may have a chemical and atomic composition unique from other galactic molecular clouds.
The second half of the thesis discusses tests performed in the UVCS laboratory at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, on the equipment used at eclipses for the Williams College coronal polarization and temperature experiment. The goal of the tests was to determine the linearity of the CCD camera used in the system and to determine if there is significant internal polarization of the equipment itself that would affect polarization measurements of the solar corona. Our results indicate that this internal effect is most likely not a significant source of error in eclipse measurements.
Properties of Planetary Nebulae
Bethany E. Cobb
Planetary nebulae (PNe) are important in the study of stellar processes and galactic chemical evolution. A large, homogeneous data set of 65 PNe was examined to study the behavior of various PN properties. Morphologies were determined visually for 38 of these PNe and bipolar nebulae were found to have slightly higher N abundances and slightly lower O abundances than elliptical PNe, in agreement with the literature. The possibility that S, C1, and Ar could be used as surrogates for Fe in galactic chemical evolution studies was also examined. Because the [S/H + Ar/H] abundance increases as the metallicity of the Galaxy rises and because the abundances of S, Ar, and C1 rise in lockstep fashion with O, we believe it may be possible to use these elements as Fe surrogates. Additionally, we confirm the trends seen in the entire data set by separately examining only the most accurately derived data.


A Poor Pore? Two-Hybrid Analysis of Avirulent virB10 Mutants and Site-Directed Mutagenesis of virB7 and virB8
Jessica Bauman
Interkingdom DNA delivery from Agrobacterium tumefaciens to susceptible plants results in the formation of crown gall tumors on the infected plant. The VirB7, B8, B9, and B10 proteins previously have been shown to interact in homotypic and heterotypic interactions to form part of a transport apparatus that aids in transferring the single-stranded T-DNA into the host plant cell. We have continued to study these interactions, specifically those of VirB10 with either VirB8 or VirB9, using two-hybrid analysis. In order to determine which domains of VirB10 may be involved in the interaction with either VirB8 or VirB9, site-directed mutagenesis of virB10 was previously carried out in an attempt to eliminate VirB10 function and thereby possibly identify essential amino acids. Of the forty-some mutant virB10s generated, nine failed to complement a virB10 deletion strain as determined by tumor assays, yet all but to resulted in wild type levels of protein accumulation. In our current work, we have fused the nine mutant virB10 sequences to a DNA activating domain and tested with wild type virB8 or virB9 fused to the LexA binding domain. Two-hybrid screens for protein-protein interaction with lacZ and LEU2 as reporter genes have revealed potential aberrant interactions between certain altered VirB10’s and VirB8, and especially VirB9. These data not only support Jutta Bohne and Andrew Binns’ observation that the whole VirB10 protein (minus its transmembrane domain) interacts with VirB8 and VirB9, but they also provide preliminarily identification of specific regions in the C-terminus that are required for VirB10 to interact with VirB9.
We have also utilized site-directed mutagenesis to insert a stop codon into either the virB7 or virB sequence on the high copy plasmid p661. These constructs will be used to test further a model of translational coupling between either the VirB7-B10 proteins or VirB8-B10 proteins.
Investigating Phosphorylation of Vaccinia Virus dUTPase
Michael Chiorazzi
Deoxyuridine triphosphatase (dUTPase) is an important enzyme involved in DNA metabolism. Very little is known about its regulation, though increased activity has been correlated with phosphorylation. To assess directly the role of phosphorylation in dUTPase’s activity, four sites of potential phosphorylation were mutated in the vaccinia dUTPase gene and these mutants assayed for activity using a TLC-based test. Two of the mutants showed less activity than the wild-type enzyme suggesting that the sites mutated in these forms may be important for regulation. The remaining two mutants showed little difference from wild-type dUTPase, although one mutant may have had greater activity than wild-type. As differences in activity can only be attributed to phosphorylation if vaccinia dUTPase is shown to be phosphorylated in the Escherichia coli overexpression system, immunoprecipitations of radiolabeled dUTPase were performed to detect labeling with [32]P-orthophosphate. In this effort, the sensitivity of the immunoprecipitation protocol was improved by varying the amount of radio-label and antibody as well as by inhibiting endogenous transcription with rifampicin. [32]P-labeling results suggested that dUTPase is in fact phosphorylated in the E. coli system.
Characterization of the Putative Promoter Inside the virB Operon of Agrobacterium tumefaciens
Susan E. Levin
The genes required for export of the T-DNA from the plant pathogen Agrobacterium tumefaciens are encoded by the virB operon which is located on the Ti-plasmid. Although operons are characterized by the presence of a promoter upstream of the first gene in the co-transcribed set of genes, our lab recently identified a putative promoter sequence between the end of virB6 and the translational start of virB7 that is highly homologous to the –10 and –35 consensus regions of known stationary phase promoters. In order to test our hypothesis that the sequence indeed contains an active promoter, we cloned the putative promoter sequence through the translational start of either virB7 or virB8 into a promoterless lacZ construct. The resulting plasmids were then introduced into A. tumefaciens strains, and liquid β-galactosidase assays were used to test for transcriptional activity. We determined that the putative promoter exhibits higher levels of activity in the virB8 fusion than in the virB7 fusion suggesting that the promoter regulates sequences downstream of virB7. Site-directed mutagenesis of the –10 and –35 regions altered the β-galactosidase activity, thereby demonstrating that the specific sequence itself is responsible for the observed activity. The –10 region mutant exhibited higher levels of activity than its wild type counterpart, while mutations in the –35 region completely abolished activity. In A. tumefaciens strains that are either cured of the Ti-plasmid or have a different Ti-plasmid than the one in which the putative promoter sequence is present (pTiA6NC), both the –10 region mutant and wild type plasmids had identical activity. These findings provide evidence for a Ti-encoded repressor which normally represses the wild type sequence at the –10 region. The presence of a LysR recognition sequence upstream of the putative promoter suggests that a LysR family member may be involved in regulating the promoter. Similarly, although ros mutants do not alter promoter activity, the presence of a putative ros box within the promoter sequence implicates a ros-like factor in regulation of the promoter. While octopine, temperature, and growth phase did not affect the β-galactosidase activity, the addition of acetosyringone appears to cause a negative regulatory effect, leading us to postulate that the promoter is not active during T-DNA transfer but rather directs the expression of a subset of virB genes required for conjugal receipt.
Ceramide Quantification by High-Pressure Liquid Chromatography Following Hydride Reduction and Derivatization with 9-Fluorenylmethyl Chloroformate
Matthew W. Luedke
Ceramides and their derivatives act as structural components of cellular membrane, cell-signaling molecules, and second messengers (Structure 1). In their second messenger role, ceramides have been implicated in initiation of apoptosis. Several methods for ceramide quantification exist, however none of these existing methods provides the quantitative sensitivity and accuracy achieved for many other biomolecules. This thesis details the development of a protocol for the quantification of mixed samples of ceramides. We have elucidated a method to convert ceramide species to ceramines (Structure 2) with hydride reducing agents, facilitating subsequent derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl, Structure 3), which allows for quantification of the lipids by reverse-phase high-pressure liquid chromatography (RPHPLC) with fluorescence detection.
Construction of a Histidine-tagged Form of VirD4, the Putative “Coupling Protein” in the Type IV Secretion System of Agrobacterium tumefaciens
Maywa Montenegro- deWit
The type IV conjugative transfer system of Agrobacterium tumefaciens is capable of exporting nucleoprotein complexes to plant cells as well as to other bacteria. The VirB membrane proteins are thought to mediate substrate transfer by assembling into a multimeric transfer apparatus that spans both bacterial membranes. An essential factor in the transfer process, called the VirD4 coupling protein, is likely to interface the exported substrate with the subunits of the VirB complex. As such, VirD4 may have the unique role of dictating the specificity of the interactions that can occur between different transfer substrates and pore components. In addition to the transfer of oncogenic T-DNA to plant cells, the VirB/VirD4 system is also capable of delivering the broad-host range plasmid RSF1010, and the monomeric proteins VirE2 and VirF. Several lines of evidence indicate that VirD4 directly recognizes the T-complex and brings it into association with the VirB pore. It is less clear how VirD4 functions in the delivery of protein-protein complexes and monomeric protein substrates; two hypothetical models are presented here and discussed.
In order to evaluate VirD4 function experimentally, it is necessary to have a means of detecting the protein. We chose to attach a six-histidine tag to the virD4 sequence, as this method enables easy detection as well as isolation of the tagged protein. Towards this goal, we constructed a plasmid containing the fragment: virD promoter/ ‘virD2/virD3/virD4/virD5’ and used this plasmid as the template for site-directed mutagenesis of the virD4 gene. We successfully introduced a SalI restriction site at the start of the virD4 coding region in the plasmid pMM2-F. The virD4 gene was then excised as a SalI fragment for ligation into the pYW15a vector plasmid. This vector contains a six-histidine sequence directly upstream of the SalI site, resulting in a 6-His fusion with the product of the inserted gene. Restriction analysis of the ligation reaction products indicated that contaminating pMM2-F vector fragments predominated in the solution. Thus, a variety of different methods were pursued to isolate either the fragment containing virD4 or the pYW15a-virD4 recombinant plasmid. Although these attempts have not to date been successful, we propose some promising alternate strategies. Once we have obtained the 6xHis-VirD4, we plan to employ the tagged protein in experiments designed to elucidate VirD4-VirB and VirD4-substrate interactions, with particular attention to the models described in this thesis.
Sphinganine Hydroxylase Expression in Arabidopsis and Corn: Detection of the Sphinganine Hydroxylase Transcript by Northern Analysis
Theresa C. O’Brien
The expression of sphinganine hydroxylase was examined in Arabidopsis thaliana and Zea mays tissue by Northern analysis. Probes for hybridization were designed using the sequences for the recently characterized A. thaliana sphinganine hydroxylase genes, F14L17.5 and T6C23.16, and the Z. mays sphinganine hydroxylase AW146867 EST. Northern analysis using a PCR-derived F14L17.5 probe was successful in detecting a sphinganine hydroxylase transcript of approximately 1.15 kb when A. thaliana total RNA was probed and the temperature for hybridization was 55 °C. Non-specific or very limited binding of the F14L17.5 probe was observed when Z. mays RNA or a 65 °C hybridization temperature was used. A plasmid-derived T6C23.16 probe also failed to cross-react with Z. mays RNA or to detect the hydroxylase transcript when subjected to Northern analysis at 65 °C. Detection of A. thaliana sphinganine hydroxylase transcript by the T6C23.16 probe at 55 °C was limited, prohibiting its use in experimental analysis. A sphinganine hydroxylase transcript of approximately 1.25 kb was detected by Northern analysis at 55° C using the Z. mays AW146867 EST probe and RNA isolated from Z. mays tissue. The AW146867 probe also detected an A. thaliana sphinganine hydroxylase transcript of approximately 1.20 kb, though hybridization to the mRNA was too weak to be used for experimental analysis. The AW146867 probe failed to detect any transcript at 65 °C. These results indicate that detection of sphinganine hydroxylase transcript by Northern analysis requires a hybridization temperature of 55 °C and that probes and RNA be from the same plant species. Preliminary results of Northern analysis using tissue that was treated with fumonisin B1 or distilled water suggest that the fungal mycotoxin does not dramatically enhance expression of sphinganine hydroxylase in vivo.
Characterization of an auxin-regulated putative F-Box protein in Arabidopsis thaliana
Christine M. Palmer
Auxin is an extremely important plant hormone that regulates many aspects of plant growth and differentiation. One approach to learning more about this hormone is to look at the genes whose expression is regulated, either positively or negatively, by auxin. Previous microarray analysis had revealed an auxin-upregulated gene in Arabidopsis thaliana that was identified as encoding a putative F-box protein (PFP). Other known F-box proteins act in the ubiquitin degradation pathway and serve to identify which proteins will be labeled for degradation. Some F-Box proteins are known to act in the auxin pathway. PFP was found to be rapidly upregulated in response to even very low concentrations of auxin, indicating that it functions early in auxin response. A mutant line with a T-DNA insertion in the PFP gene was identified as having another T-DNA insertion in the plant genome, necessitating further backcrosses. Nonetheless, the mutant line was found to produce little or no PFP transcript indicating that there was a successful knockout. Preliminary observations showed that pfp mutants develop slightly faster than wild type plants, but there is no definite correlation between this phenotype and the disrupted gene.
Food Availability In Aquatic Insect Communities: A Test Of Three Hypotheses
Michelle Ruby
Stream insect communities depend on allochthonous leaf litter for food. This food varies in availability depending on leaf type and time. The effects of this changing food availability were tested by creating artificial leaf packs of Lonicera morrowii, Acer saccharum, Fagus grandifolia, and Tsuga canadensis leaves and placing them in a stream for 7, 14, 21, or 28 days. The insect communities were then analyzed. Three theories about community responses to changing food availability were investigated: the paradox of enrichment, the exploitation ecosystems theory, and the dietary continuum theory.
The four leaf types decomposed at different rates, with L. morrowii > A. saccharum > F. grandifolia > T. canadensis. These decomposition rates can be used to indicate the initial amount of food available to the system as well as to extrapolate the timing of food availability.
Measures of community diversity decreased as food availability in the system increased. Though this relationship was not significant by linear measures, the pattern appears to be strong in highly productive leaf packs, indicating a paradox of enrichment effect. Bottom-up forces regulated both detritivore and predator density in these patches, contrary to the alternating top-down and bottom-up control predicted by the exploitation ecosystems theory. Insect abundance varied significantly with decomposition state, peaking at intermediate stages of decomposition. Decomposition state was also more important than leaf type in determining insect preferences, supporting the dietary continuum theory.
Bottom-Up and Top-Down Effects in a Temperate Ant-Plant Mutualism
Brooke Ray Smith
By manipulating nutrient availability and ant attendance of Helianthella quinquinervis (aspen sunflower), I was able to examine both the bottom-up effects of fertilizer on this ant-plant mutualism, and the modifying interaction of ants on herbivores as well as on plant quality. The presence of mutualistic ants significantly reduced the number of seed puparia, but not the weight or density of adults emerging from a given inflorescence. Seed predators were also significantly limited from above by parasitoid wasp predation. Increased plant quality, measured by height and inflorescence size, increased fly puparia, adults, and adult weight, but the addition of fertilizer could not be attributed to increased plant quality. Rather, seed weight significantly decreased in response to nitrogen addition. Although much of the variation in this system remains unexplained, H. quinquinervis reproductive success is determined primarily by top down herbivory, as well as mutualistic ant attendance and bottom-up resource availability.
A Screen for Novel Neurodegenerative Genes Using Drosophila Enhancer Promoter Lines
Xiao Tan
1,697 homozygous viable lines of Drosophila melanogaster mutated with P{EP}-element insertions were maintained at 25°C and screened for early death. EP2182 homozygotes showed a consistent, shortened lifespan accompanied by delayed onset ataxia. Histological examination of brain sections of EP2182 homozygotes showed signs of late onset neurodegeneration. EP2182 is inserted in cytology band 54A2 on chromosome 2R. The insertion location was confirmed using inverse PCR, and there are three predicted genes within a 20kB region surrounding the site of insertion of EP2182. Two of the genes are confirmed transcripts (CG11395 and CG17290), and the third is an open reading frame that encodes the RNA-directed DNA polymerase of the mobile element Jockey. CG11395 shares sequence identity with several proteins that affect gene expression, including murine S19560 Proline-Rich Protein MP4, SRA4 Rat CTD-Binding SR-Like Protein RA4, C. elegans Annexin, and Drosophila Osa (Eyelid). CG17290 encodes Drosophila Ribosomal Protein S20. It is unclear which of these genes, if any, is affected by the EP2182 insertion. It is hypothesized that the EP2182 insertion has disrupted a cis-regulator element, thereby altering the expression of these or a yet unknown gene that is important for adult neuronal function. It is also possible that a different genetic lesion, unlinked to the EP insertion, causes the degenerative phenotype observed in EP2182 homozygotes.


Studies Toward the Asymmetric Total Synthesis of Marine Natural Products Octalactin A and Hennoxazole A
Emily Balskus
Part I: Model Studies for a Ring-Closing Metathesis Route to Octalactin A
The natural product octalactin A is a marine metabolite that shows promising cytotoxic activity in vitro. This potentially useful biological activity, along with the interesting structural features of the molecule, makes the natural product an important target for synthetic chemists. The most important structural feature of octalactin A is an 8-membered lactone core. Two total syntheses had been completed at the start of our investigations.
This work describes a proposed total synthesis of Octalactin A, which relies on a ring-closing metathesis reaction to form the key 8-membered lactone. To explore the feasibility of this approach, a model study using simple acyclic ester precursors was conducted. The synthesis of each model system is described, as well as the attempts to affect the metathesis reaction. Upon completion of this model study, it was concluded that the initial metathesis disconnection did not show promise for the synthesis and would need major revision. At this point in the study, a total synthesis of octalactin A using ring-closing metathesis was reported by Buszek and co-workers. Their work prompted the discontinuation of our efforts toward a total synthesis.
Part II: Progress Toward the Total Synthesis of Hennoxazole A
Hennoxazole A (1a) is a bisoxazole-containing marine natural product isolated from sponges. This molecule displays potent anti-viral activity against Herpes Simplex I and exhibits analgesic activity. Besides the bisoxazole unit, other notable structural features of hennoxazole A include a pyran ring and a skipped triene side chain containing a remote stereocenter. Three total syntheses of hennoxazole A have been accomplished to date.
This work describes efforts toward a concise, asymmetric total synthesis of hennoxazole A. The key reaction in the proposed route involves an oxazole metallation/alkylation sequence to install the skipped triene side chain. To explore this key coupling reaction, one of the early intermediates in the synthesis (43) was used as a model system to test the alkylation. Synthesis of the model system is described along with the results of the metallation studies. Ultimately, lithium diethylamide was found to be a suitable base to affect the regioselective metallation required for the proposed reaction. Alkylation of the protected model system with allylic halides provided the desired products in good yield. These promising results suggest that the approach will be viable for the total synthesis of the natural product.
Developing Model Systems of Cofactor F430: Electrochemical Studies of Tetraazamacrocyclic Nickel Complexes
David Chung
The molecular mechanism of methanogenesis has yet to be elucidated. In addition, it is unclear why nature has chosen a rare biological metal–nickel–and the most highly reduced tetrapyrrole found in nature as the site for methane catalysis. The development of tetraazamacrocyclic nickel model systems may contribute to a better understanding of both nickel chemistry and an important biological process. Complexes found in the literature are identified as promising F430 model systems, and initial electrochemical studies are described. Cyclic voltammetry and spin density calculations have primarily been performed on three complexes, Ni(II)-5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,12-tetraene (Ni-MeHMe[14]), Nickel(II)-7,15-diphenyl-1,5,9,13-tetraazahexadeca-5,7,13,15-tetraene (Ni-HPhH[16]), and [Nickel(II)-(Ph2[16]hexaenatoN4)](PF6) (Ni-HPhH[16]ox). Depending on solvent, Ni-MeHMe[14] undergoes quasi-reversible reduction and irreversible oxidation, and Ni-HPhH[16]ox undergoes one irreversible reduction followed by a second quasi-reversible reduction and a quasi-reversible oxidation. Ni-HPhH[16] undergoes a quasi-reversible reduction, but it was difficult to characterize the oxidation due to solvent limitations. Ni(III) and Ni(I) complexes are likely intermediates in these redox processes. The literature suggests that a Ni(III) complex is directly generated upon oxidation. Spin density calculations predict that the Ni(I) states of Ni-MeHMe[14] and Ni-HPhH[16] are accessible and that a ligand-based radical is generated upon reduction of Ni(II)-HPhH[16]ox.
Molecular Modeling of Bacillus subtilis ComK, LexA, and RNA Polymerase Leading to Informed Site Specific Mutagenesis
Eli Groban
The ComK protein is a transcription factor that is central to the development of competence in B. subtilis. More than one hundred genes are controlled by ComK and, in some cases, ComK activates transcription of repressed genes. In the case of the recA gene, transcription is activated in the presence of ComK without the physically displacing the repressor of this system, the LexA protein. Several lines of evidence suggest that the mechanism of ComK’s activation might involve an interaction with the alpha-carboxy-terminal domain (a-CTD) of RNA polymerase yet thus far no study explains interactions of RNA polymerase, ComK, LexA, and the promoter region of the recA gene leading to expression of the RecA protein.
Currently, there are no available crystal structures for B. subtilis ComK, LexA, and RNA polymerase. Homology models were constructed for the B. subtilis versions of the LexA protein and the a-CTD of RNA polymerase based on E. coli LexA and a-CTD analogs as well as other reference proteins. The LexA model was then docked with the promoter region of the recA gene. Analysis of the DNA binding domain, through site directed mutagenesis and binding assays, determined that His46 and Arg49 are critical for LexA binding to DNA. A THREADING algorithm was used to develop a model for the DNA binding domain of ComK. Another ComK model used homology modeling with a human High Mobility Group protein (HMG), which binds the minor groove of DNA, as the reference structure. All modeling used the InsightII package available from Accelrys Software and an SGI workstation.
The Purification of Bacillus subtilis ComK Protein
Carol Lynn Higgins
Competence is a state that develops in Bacillus subtilis as a result of high cell density and limited nutrients. When cells achieve competence, they produce a complex DNA binding and uptake system that allows them to take up exogenous DNA, which can then be recombined into their chromosomes. A host of proteins regulate competence, and the regulation of competence is dominated by the competence transcription factor ComK. Although ComK has been identified for approximately 10 years, researchers have had difficulty in purifying the protein due to a variety of factors. Methods including His-Tags and maltose binding proteins have been used with limited success and the lack of a good method of purification has hindered the study of ComK. In addition, due to poor solubility, no structural analysis of ComK has been done. The objective of this research was to clone and produce truncated versions of the ComK DNA binding domain and to determine a procedure for the purification of wild-type protein and the truncated version. ComK was overexpressed in a strain containing plasmid pET21a-comK, in which the comK gene is under the control of the T7 promoter. Cells were induced with IPTG and harvested. Protein purification of the wild-type protein was achieved using a High Q ion exchange column, a step-wise ammonium sulfate precipitation to a concentration of 50% ammonium sulfate and a gel filtration column.
Electrotonic Coupling of Supramedullary Neurons in Tautogolabrus adspersus
Nicholas Hiza
Supramedullary neurons (SMNs) are a group of neurons found in the central nervous system of many species of teleost fish. Electrophysiological exploration of the supramedullary neurons in the cunner (Tautogolabrus adspersus) suggests the cells are electrotonically coupled through gap junctions. To test this theory, a cell soma was injected with a fluorescent dye, Lucifer Yellow (521.56 MW), and neighboring somata were screened for dye coupling. Dye was observed in neighboring cells in 6 of 28 preparations. This strongly supports the hypothesis that the SMNs in this species are interconnected through gap junctions. The morphological arrangement and projection patterns of the SMNs indicate that these interconnections exist in the median dorsal fissure, possibly on neurites found projecting rostrally and caudally off the soma. Multiple fine processes were found branching off the main process of the cell. These processes have not been observed previously. Their targets are unknown, and they indicate this system may be more complex then initial expected. Finally, asymmetry in dye flow and patterns in the number of cells filled indicates that cells may exist in strongly coupled subgroups of between three and four cells. These subgroups are separated from one another by wider intersomatic intervals, and may serve as a bridge-point for information crossing the midline.
Partial Synthesis of the Protein Cutting Agent Iron (S)-1-(p-Bromoacetamidobenzyl) ethylenediaminetetraacetate and the Cloning of the Alpha Subunit of RNA Polymerase
Tracey Jackson
The partial synthesis of Iron (S)-1-(p-bromoacetamidobenzyl)ethylenediaminetetraacetate was achieved through the nitration of (L)-phenylalanine which proceeded in 28% yield. The formation of (L)-p-Nitrophenylalanine methyl ester (2) of this 4-nitro-phenylalanine (1) was then achieved in 47% yield and through displacement of the acyl group by ammonia, acting as a nucleophile, (L)-p-nitrophenylalanine methyl amide (3) was formed (21%). This was reduced to the (S)-1-(p-nitrobenzyl)etheylenediamine (4) which was formed in 100% yield.
Metallomesogenic Platinum (II) Metal Complexes with 2,2-Bipyridyl-Based Ligands; Progress Towards 1-D Conductive Materials
Carrie Jones
In the pursuit of one-dimensional conductors, we have endeavored to introduce liquid crystallinity into known anisotropic metal complexes which show promise for electrical conductivity but are typically hindered by Peierls Distortions and the constraints of crystalline solids. First, in developing such metallomesogens, we have designed and synthesized 5,5‚-disubstituted 2,2‚- bipyridine-based ligands with the object of obtaining liquid crystalline materials. Through polarized optical microscopy and differential scanning calorimetry, we have characterized the series of ligands with aliphatic chains of lengths C6-16 and found that the longer chain analogues, C12-16, have liquid crystalline mesophases. Secondly, we have coordinated these mesogenic bidentate ligands to Pt(II) square planar metal centers in order to form metallomesogens with the potential for conductance due to Pt-Pt dz2 orbital overlap along the z-axis. These Pt(bpy)X2 complexes, where X= Cl-, show liquid crystalline properties for the longer chain ligands. The Pt complexes where X= CN- or OCN- and the bisbipyridyl-platinum complexes are also being studied and show promise for liquid crystalline behavior. We believe that both the bipyridine-based ligands and the metal complexes form columnar phases in which the discotic-like molecules stack into columns that self-align into large domains. This behavior should be convenient for future oxidation studies since the molecules are arranging themselves in one-dimensional, wire-like forms.
Recognition of Canonical and Bizarre tRNA Substrates by Alanyl-tRNA Synthetase: An Investigation of Animal Mitochondria Presents a Possible Answer to the Problem of Coevolution
Alix Partnow
Proper aminoacylation is a vital part of protein synthesis. Although the chemical reactions involved in tRNA charging are conserved, the enzymes that mediate these reactions and the tRNAs that are charged can vary greatly. In fact, 20 distinct systems of enzyme/substrate recognition corresponding to each of the 20 amino acids have evolved. While the majority of amino acyl tRNA synthetases recognize tRNA based upon the anticodon sequence, a unique system has evolved in the case of alanine. The alaRS/tRNAAla interactions that occur in prokaryotes, cytoplasm, and chloroplasts are highly conserved. E. coli provides a useful model system for the canonical case. However, due to the evolution of bizarre tRNA structures these trends break down in the animal mitochondria. Here the alaRS mediated aminoacylation of two distinct species of mitochondrial tRNAAla are investigated. The first case of study is the roundworm C. elegans, it involves a tRNA that has retained the key recognition elements found in the acceptor stem of the canonical substrate but lacks a TΨC loop. Using a chimeric transcript in which the canonical E. coli acceptor stem was fused onto the C. elegans mitochondrial body, the importance of secondary and tertiary interactions was shown. Additionally, charging of the full-length canonical substrate by the mitochondrial alaRS was observed. The second system examined was that of the human mitochondria. Although the human mt tRNAAla does exhibit the full cloverleaf conformation, the acceptor stem does not possess the canonical recognition elements. A system for the purification of the human mitochondrial AlaRS (HMA) was devised and microhelices were designed in hopes that future experiments will elucidate the primary points of HMA recognition. It was also seen that, like the C. elegans enzyme, the HMA was able to recognize and charge the full length canonical tRNAAla. These findings lead to the conclusion that these organisms have adopted the use of less specialized alaRS enzymes in order to combat the problems associated with coevolution; in this way the necessary interactions between conserved nuclearly encoded proteins and highly mutable mitochondrial tRNA molecules can be facilitated.
Overtone Spectroscopy of Hydrofluorocarbons: Intensities and Anharmonic Resonances
Adam Steeves
Fourier transform infrared spectroscopy and long pathlength absorption spectroscopy are used to record the fundamental and first three overtones of the C-H stretching transition in 1,1,1,2,3,3,3- and 1,1,1,2,2,3,3-heptafluoropropane. All spectra show evidence of structure due to Fermi resonant coupling between the C-H stretching and either of two nondegenerate C-H bending modes. The spectra of the 1,1,1,2,2,3,3- isomer, particularly of the 1st and 2nd overtone, show larger perturbations than the corresponding spectra of the 1,1,1,2,3,3,3- isomer, implying a stronger Fermi resonance term in the potential. Additionally, a simple spectroscopic Hamiltonian including only C-H stretch/bend interactions does not apply as well to the 1,1,1,2,2,3,3- isomer, therefore indicating the importance of additional Fermi interaction of the C-H stretching mode with C-C stretching modes in this molecule. The oscillator strengths (absolute intensities) of the fundamental through third overtone of the C-H stretching are determined from the recorded spectra. For the 1,1,1,2,3,3,3- isomer, the oscillator strengths are 6.53(65)E-07, 6.11(18)E-08, 5.35(44)E-09, and 4.27(64)E-10 for the fundamental, 1st, 2nd, and 3rd overtone transition respectively. For the 1,1,1,2,2,3,3 isomer, the oscillator strengths are 1.85(19)E-06, 5.84(09)E-08, 7.14(17)E-09, and 6.46(39)E-10 for the fundamental, 1st, 2nd, and 3rd overtone respectively. These oscillator strengths are compared to those predicted by Apgar [2001] on the basis of ab initio calculations at the B3LYP/6-311++G(2d,2p) level of theory. Both isomers show agreement with the predicted trend of an order-of-magnitude decrease for each successive overtone. The results do not, however, show as good agreement as is achieved for OH overtones in alcohols and acids. Further, the agreement is, in general, better for the 1,1,1,2,3,3,3 isomer, and for both molecules shows increasing agreement at higher overtones. These observations are consistent with an intensity loss in overtone spectra due to Fermi resonance.
Toward a General Asymmetric
Alan Velander
Kava is a traditional Polynesian herbal remedy and currently beleaguered alternative medicine, which is extracted from the Piper methysticum root and composed of fifteen related kavalactones. In order to separately generate samples of each enantiopure kavalactone, four general asymmetric kavalactone syntheses were developed. The first route employed a Nagao chiral auxiliary acetate aldol reaction, followed by a modified malonate ester addition and a two-step, one-pot lactonization/methylation, to generate (+)-kavain in 64% and (+)-7,8-dihydrokavain in 42% yield. The second route demonstrated a lactonization/methylation on known Carreira chiral catalyst aldol adducts to give (+)-kavain in 62% and (+)-7,8-dihydrokavain in 87% yield. To avoid decomposition of highly oxygenated aldehydes, a Stille reaction was incorporated into the previous syntheses, coupling a vinylstannyl lactone and aryl iodide as a final, versatile step. The Nagao Stille route was pursued with 3-tributylstannyl acrolein as the starting aldehyde. The titanium enolate aldol reaction was complicated by protodestannylation, which was happily avoided in the tin enolate aldol reaction. The malonate addition was successful but its subsequent purification was difficult, requiring deactivated silica column chromatography and giving lower than expected yields. The lactonization/methylation was completed to give the tributylstannyl lactone in 31% yield over the three steps. A preliminary, proof-of-concept Stille coupling was then performed, giving (+)-kavain and a palladium-to-phosphorus furyl migration byproduct, in a 4:1 unresolved mixture.
Synthesis of Benzocanthinones
Peter Webb
A synthesis of benzocanthinone was achieved in a 22% yield (unoptimized) in five steps with the key step being a radical reductive cyclization. The radical reductive cyclization should prove to be a versatile route to isomers of benzocanthinone as well. Progress was made towards the total synthesis of benzoazacanthinone. Preliminary pursuit of a projected route to benzo-g-canthinone would complete this series of benzocanthinones. If formation of the amide bond with acryloyl chloride were optimized, then the versatility of the radical reductive cyclization would be proven with the production of canthinone. A two-step preparation of benzocanthinone was performed which also utilized a radical reductive cyclization. This latter pathway produced the desired product and a regioisomer; it was established that the regioselectivity was a function of the halogen substituent.


Modules in LOOM and Their (Separate) Compilation
Douglas Thunen
With increasing large programs being developed, there arises a need for dividing what could be unwieldy programs into smaller, more tractable pieces. Module systems address this by providing a means for organizing code into more reasonable chunks. Without the ability to separately compile these pieces, however, program development could remain excessively costly due to lengthy recompilations. In this talk, we discussed work on the language LOOM that attempts to address these problems. We discussed LOOM’s module system and then described a mechanism for the separate compilation of modular LOOM program.

Improving the Performance of Neural Networks Through the Developmental Ordering and Presentation of Input Examples
Evan Sandhaus
This thesis investigated the utility of ordering the input examples presented to a neural network. When training a neural network on a collection of input examples, it has become standard practice to randomize the order of the inputs from epoch to epoch. This practice is thought to improve the generalization of trained networks, because it lowers the probability that a particular ordering of examples will bias the network towards poor accuracy.
Yet in a 1993 study, Jeffrey Elman suggests that a careful ordering and presentation of input data can boost overall network performance. He shows that a simple-to-complex ordering of input examples coupled with a carefully contrived presentation of those examples enables a neural network to learn a natural language processing dataset that had previously appeared unlearnable.
The Search for Universal Aperiodic Tile
Feng Zhu
One of the most remarkable discoveries in the theory of tilings concerns the existence of sets of prototiles which admit infinitely many tilings of the plane without any of these tilings being periodic. Sets of prototiles with this property are called aperiodic. A set of two tiles with this property was discovered by R. Penrose in 1974. It is still an open problem whether there is a single universal aperiodic two-dimensional prototile. In 1996, Gummelt identified a single decagon covering that covered the plane aperiodically. Our research is based on this aperiodic covering and will generate a non-traditional sponge-like universal tile. The first part of the talk provided some background about tilings and an overview of some recent approaches in searching universal aperiodic tile. The second part described our approaches to build the sponge-like tile and results we have obtained.


The Geochemistry and Tectonic Setting of the Thorofare Andesite, Fox Islands, Maine
Nathan C. Cardoos ’02
Silurian volcanic rocks occur in the northern part of Vinalhaven Island and along the south shore of North Haven Island (the Fox Islands) in Penobscot Bay, Maine. They overlie the fossiliferous Lower (?) Silurian Ames Knob Formation and are intruded by the Vinalhaven granite pluton (420±1 Ma; David Hawkins, pers. comm., 2002), one of several plutons of the Coastal Maine Magmatic Province produced by the repeated injection of mafic magma into a silicic chamber at a shallow crustal level. The younger members of the volcanic pile - the Vinalhaven Rhyolite (Newton, 1999) and underlying Vinalhaven Diabase (Klemetti, 1999) - resemble the rocks of the pluton in their apparently bimodal character, though the "diabase" is geochemically a basaltic andesite to andesite and has petrographic features suggesting it is a hybrid.
Older volcanics in this Silurian sequence are the felsic tuffs in the Polly Cove Formation (named by Ollie Gates, 2001), the stratigraphic equivalent of the Ames Knob, the overlying Thorofare Andesite, and the tuffs and tuff breccias of the lower part of the Seal Cove Formation (Gates, 2001; Szramek, 2002). The Thorofare forms a 750-meter-thick pile of gray to reddish-brown intermediate lava flows and breccias on either side of the Thorofare strait and on small islands within it. The fragmental rocks are dominated by laharic breccias but also consist of autobreccias, bedded tuff breccias, and rare airfall tuffs. Breccia clasts are mainly andesite and mudstone, with locally abundant felsic volcanic fragments that may be the equivalent of volcanics in the Upper Cambrian Castine and Ellsworth formations to the north.
Lower greenschist metamorphism and local hydrothermal alteration have largely obscured the primary mineralogy of the flow units in the Thorofare. The least altered samples from it preserve an intergranular fabric of mostly andesine and clinopyroxene. On a Winchester and Floyd (1977) classification diagram using immobile trace elements, these rocks plot mostly as andesites with overlap into the fields of basaltic andesite and dacite. Most flow samples plot within the IAT (island arc tholeiite) field of a Mullen-type (1983) minor-elements tectonic discrimination diagram and in the calc-alkaline field of a Ti-Zr-Y diagram (Pearce and Cann, 1973). A trace element spider diagram after Pearce (1983) indicates relative enrichments in large-ion lithophile elements (LILEs) and relative depletions in some of the Ti-group elements, a pattern consistent with an arc setting.
The welded tuff of the Polly Cove Formation indicates that a period of explosive felsic volcanism occurred prior to the deposition of the Thorofare Andesite, and the tuffs of the lower Seal Cove Formation show that felsic volcanism continued after Thorofare time. These three units thus represent a significant period of volcanic activity that occurred before the onset of bimodal volcanism and plutonism represented by the Vinalhaven Diabase, the Perry Creek Formation, the Vinalhaven Rhyolite, and the Vinalhaven Plutonic Complex.
Geochemical tectonic discriminant diagrams and the recently determined preliminary date for the Vinalhaven Pluton suggest that the andesite to dacite lava flows and breccias of the Thorofare Andesite were deposited in the Early (?) Silurian Period in a moderately evolved island arc or continental margin setting prior to the accretion of peri-Avalonian arc systems to the Laurentian mainland. Later Silurian (ca. 420 Ma) bimodal plutonic and volcanic units indicate a change from an arc to a back-arc environment during the evolution of Vinalhaven. This interpretation supports (1) Stewart et al‚s (1995) model for the closing of the Iapetus Ocean, which describes arc terrane amalgamation offboard of ancestral North America prior to the accretion of this composite landmass to form coastal Maine, and (2) Pinan-Llamas‚(2002) recent work on the Machias-Eastport volcanics of easternmost Maine, which points to a change in the tectonic setting of the Coastal Volcanic belt during the mid-Paleozoic from arc-related to within plate by the end of the Acadian Orogeny.


Singular Maps of Surfaces into Hyperbolic 3-Manifolds
Eric Michael Katerman
We construct singular maps of surfaces into hyperbolic 3-manifolds in order to find upper bounds for meridian length, longitude length, and maximal cusp volume of those manifolds. We also provide ample background and history of hyperbolic geometry and 3-manifold theory for this exposition to be accessible to undergraduate mathematics majors. Generalizations and attempts to strengthen our results are also included for completeness.
Spatially Explicit Biological Population Models
Jonathan A. Othmer
This thesis presents a spatially explicit hybrid system population model. Populations are assumed to exist in discrete patches, which we approximate using a hexagonal tiling of the plane. Dynamics within one patch are controlled by a system of differential equations while intra-patch dynamics are controlled via a set of transition functions and threshold values. We explore a variety of behaviors of this model, filling the plane, reaching static equilibrium, and reaching dynamic equilibrium. We also present and explore a spatially attracting, self-synchronizing cycle that arises out of the model.
On Solutions to the Generalized Pell Equation with Applications to Diophantine Approximation
Charles Samuels
Suppose pn/qn are the convergents of c, where c is a positive integer not a perfect square. We show that Newton’s method applied to F(x) = x2c with initial approximation pml–1/qml–1, for any natural number m, generates the sequence {p2nml–1/p2nml–1}, n = 0,1,2,.... Subsequently, we generalize these results to all functions of the form F(x) = x2bxc, where b > 0, c > 0 are integers such that b2 + 4c is not a perfect square. We finally explore the dynamics of some polynomial functions in the p-adic numbers.


A Precise Measurement of the Stark Shift in the Thallium 6P1/2 → 7S1/2 378 nm Transition
S. Charles Doret
We have completed a new precise experimental measurement of the Stark shift constant, kStark for the 6P1/2 → 7S1/2 E1 transition in atomic thallium. In this experiment a recently completed atomic beam apparatus is used along with a frequency stabilized source at 378 nm. Two independent experimental methods are used yielding a final value of kStark = 103.34(39) kHz/kV/cm)2. This represents a factor of 15 improvement in precision over previous measurements, and now exceeds the accuracy of the current thallium wavefunction calculations. A new round of such calculations in [KPJ01] combined with a recent thallium parity non-conservation experiment ([Vet95]) provide a test of fundamental electroweak physics. Results such as ours are necessary to guide the further refinement of the atomic theory allowing for improved Standard Model tests in the future.
An Investigation of Ultrafast Exciton Dynamics in GaAs
Alexander G. Glenday
The ultrafast dynamics of excitons in semiconductors has been extensively studied both theoretically and experimentally for the last decade. The question of the effect of quantum confinement of the excitons from three or two dimensions, however, has neither been asked nor answered. In this thesis we present very preliminary data that shows the viability of our experimental setup for measuring the ultrafast dynamics of excitons with a four wave mixing technique. We also describe some of the well-understood linear effects of two dimensional quantum confinement of excitons and a semi-classical, phenomenological model for four wave mixing which will eventually be fit to the data.
A Monte Carlo Study of DNA Beacon Kinetics
John M. Parman
With complementary base pairs at each end, single stranded DNA (ssDNA) can fold into hairpin structures. By labeling one end with a fluorophore and the other with a quencher, the ssDNA become molecular beacons. Goddard et al. [Phys. Rev. Lett., 85, 2400 (2000)] measured hairpin opening and closing times using fluorescence correlation spectroscopy. Differences in the closing times of poly(A) and poly(T) hairpins indicate that ssDNA base pair stacking is an important kinetic factor. We use Monte Carlo simulations to measure the dependence of hairpin closing and opening times on base pair stacking and chain length. We measure stacking energies for adenine-adenine stacks from the simulation results that are in good agreement with experiment. Simulation results for loops with a single defect as well as scaling results are also presented.
Photoisomerization and Structural Competition Using an Improved Form for π-Electronic Interactions in Polyenes
Hans F. Stabenau
Photoisomerization reactions in polyenes occur with striking speed and efficiency. We present a model that illuminates the physical mechanism of these ultrafast reactions. Molecular properties are calculated using a Pariser-Parr-Pople type extended Hubbard Hamiltonian in a tight-binding basis. We perform independent electron calculations on uniform chains to develop intuition, and present analytical results for the ethylene molecule. The results motivate the development of a torsionally dependent improvement to the classic Ohno parameterization of the extended Hubbard model. The parameters of the model are fit to experimental data. Results for the photoisomerization of a retinal analog are presented. We find that competition between the stabilizing π-bonding interactions and the destabilizing Coulomb repulsion of the π-electrons underlies both the ultrafast photoisomerization of retinal and the general torsional properties of polyenes.
Two Completely Independent Problems in Astrophysics: Radio Observations of Molecular Emission and Absorption Lines & The Internal Polarization of the Williams College Coronal Eclipse Equipment
Gabriel B. Brammer
The first section of this thesis discusses radio observations made with the Nobeyama Radio Observatory 45-m millimeter telescope and the Steward Observatory 12-m millimeter telescope to detect molecular emission lines. The observations are for three main projects: to determine the isotopic ratios of a variety of atoms (D/H, 12C/13C, and 14N/15N) in a sample of molecular clouds distributed throughout the Milky Way Galaxy to model galactic chemical evolution; to observe a variety of molecules in a cloud 28 kpc from the galactic center, thought to be representative of the material from which the Galaxy formed; and to observe deuterated molecules in galaxies at high-redshift to determine an estimate of the primordial D/H abundance of a few seconds after the Big Bang. The D/H abundance of the Milky Way can be used, with models of deuterium processing, as another method to determine the primordial D/H abundance, which can be used to determine the baryonic density of the universe. We present results of DCN detected in ten galactic sources and HC15N detected in nine of the ten sources. We conclude with a list of fifteen molecules detected in the cloud at the edge of the Galaxy, for which preliminary analysis indicates that this cloud may have a chemical and atomic composition unique from other galactic molecular clouds.
The second half of the thesis discusses tests performed in the UVCS Laboratory at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, on the equipment used at eclipses for the Williams College coronal polarization and temperature experiment. The goal of the tests was to determine the linearity of the CCD camera used in the system and to determine if there is significant internal polarization of the equipment itself that would affect polarization measurements of the solar corona. Our results indicate that this internal effect is most likely not a significant source of error in eclipse measurements.
Properties of Planetary Nebulae
Bethany E. Cobb
Planetary nebulae (PNe) are important in the study of stellar processes and galactic chemical evolution. A large, homogeneous data set of 65 PNe was examined to study the behavior of various PN properties. Morphologies were determined visually for 38 of these PNe and bipolar nebulae were found to have slightly higher N abundances and slightly lower O abundances than elliptical PNe, in agreement with the literature. The possibility that S, C1, and Ar could be used as surrogates for Fe in galactic chemical evolution studies was also examined. Because the [S/H + Ar/H] abundance increases as the metallicity of the Galaxy rises and because the abundances of S, Ar, and C1 rise in lockstep fashion with O, we believe it may be possible to use these elements as Fe surrogates. Additionally, we confirm the trends seen in the entire data set by separately examining only the most accurately derived data.


To Laugh or Not to Laugh: Stereotyping and Prejudice and the Role of Sociocultural Norms in the Process of Self-Image Maintenance
Kelley R. Cardeira
The present research examined the interaction between social norms, stereotyping, and self-image maintenance on evaluations of derogatory humor and prejudice-relevant attitudes. In Study 1, participants received a threat to their self-esteem and were primed to value either an individualist or a collectivist orientation (or they were primed with neither). Groups of participants then watched and continuously evaluated a video compilation consisting of neutral and pejorative comedy. While watching the clips, the participants were exposed to subtle norm information in the form of a running graph that allegedly depicted the group’s ratings of the comedy. Participants in the PC condition saw a graph suggesting that the group disapproved of the derogatory humor, whereas those in the Anti-PC condition saw a graph suggesting that their peers enjoyed this humor. Participants’ actual ratings of the clips conformed strongly to these alleged norms. In addition, participants’ subsequently reported attitudes about prejudice-related policies, such as affirmative action, were significantly more pro-diversity if they had been exposed to the PC than the anti-PC norm—unless they had been primed with the individualist motive, in which case their attitudes moved against the norm. Moreover, these latter participants seemed to feel better about themselves to the extent that they defied the group norm. Study 2 more directly addressed the role of prejudice-relevant conformity in the process of self-image maintenance. The results of this study, in which neither collectivist nor individualist values were primed, replicated the findings from Study 1 concerning the effect of perceived norms on ratings of the comedy. More importantly, the results indicated that participants exposed to the PC norm felt better about themselves to the extent that they conformed to the prejudice-relevant norm, either in their ratings of the clips or in their subsequent behaviors in an ostensibly unrelated but prejudice-relevant exercise. The implications of these results, as well as suggestions for future research, are discussed.
Preschool Children’s Understanding of the Distinction Between Real and Non-Real Entities
Jessica E. Grogan
Prior research has suggested that preschool children have incomplete knowledge about the distinction between reality and fantasy. Recently, Sharon and Woolley (2001) proposed that children are uncertain about this distinction, and that mistakes occur when children are required to assign entities to real and pretend categories. Nonetheless, Sharon and Woolley (2001) noted that older preschoolers’ (4- and 5-year-olds) knowledge of real and fantastical attributes was similar to that of adults. One goal of my thesis was to replicate and extend Sharon and Woolley’s (2001) design. A second goal was to address problems with the fantasy orientation measure often used as an individual difference measure in children’s understanding of fantasy and reality. A final goal was to relate (a) children’s ability to categorize and assign attributes to real and pretend entities to (b) their ability to distinguish between physical objects and mental representations of those same objects, (c) their proneness toward fantasy, and (d) their ability to understand other people’s beliefs. Three groups of preschoolers (3-, 4-, and 5-year-olds) were tested on each of the above measures. Results showed that (a) accuracy in categorizing real and pretend entities increases between 3 and 5 years, (b) theory of mind affects the number of attributions assigned to real and fantastical entities, and (c) the physical/mental distinction is related to the real/pretend distinction. Overall, my results suggested that children show more competence in distinguishing reality from fantasy than once believed (Piaget, 1951).
Curiosity in Context: The Classroom Environment Examined
Hilary R. Hackmann
In the present study, 301 students’ behavior was coded for in order to assess the level of curiosity manifested in a classroom. A curiosity drawer box, similar to the one used by Henderson and Moore (1979) was introduced to 8 kindergarten and 10 third grade classrooms. The time spent, number of drawers opened and objects taken out, vocalizations, and teacher’s comments were recorded. As expected, kindergarten students exhibited more exploratory behavior than 3rd graders. There was a significant difference between schools, with some exploring at a consistently high or low level and others showing a decrease across the two grade levels. There were no significant gender or school type (public or private) differences. A teacher survey was returned by 114 teachers. When asked to generate a list of the five most important characteristics for their students to develop during the year, 25% of teachers wrote curiosity. However, 77% of the teachers circled curiosity from a given list of characteristics.
If You’re Happy and You Know It, Will Your Face Surely Show It?: The Illusion of Transparency in Emotional Expressions
Anna E. MacIntosh
The “illusion of transparency” is a tendency for people to believe that their internal states are more apparent to others than they actually are. This bias appears to stem from the powerful impact of an individual’s own phenomenology. Despite the realization that others are not as aware of one’s internal states as one is oneself, one’s own internal states can function as a judgmental “anchor,” making it difficult to adjust sufficiently for others’ relatively impoverished perspectives. Two experiments were performed to support the “anchoring-and-adjustment” account of the illusion of transparency in the domain of facial expression recognition. Participants were placed into either a “feel it” condition, in which they were instructed to feel certain emotions as intensely as they could, or a “mimic it” condition, in which they were instructed to simply mimic the facial expression that corresponds with each emotion. They then portrayed facial expressions and were asked to predict how many observers would be able to guess each emotion. Results of both experiments demonstrated the illusion of transparency. The second experiment also demonstrated experimental evidence for the anchoring-and-adjustment mechanism.
A Study of Language and Relationship Dynamics in the Stories of Mothers and Their Adolescent Daughters
Tiffany M. Medina
Narrative analysis in psychology often focuses exclusively on the content of a narrative and on what it reveals about human behavior, emotion, and cognition. Studying the form that language adopts—word choice, grammatical structures, and linguistic tropes—is, however, just as meaningful as examining the explicit content. This study, therefore, explores the ways that linguistic forms relate to the psychological content of stories. Fifty participants—25 mothers and their adolescent daughters—each told 2 stories into a tape recorder. One was about an argument between them and the other, about a bonding event. They then completed questionnaires that assessed their perceptions of conflict and of agency in the relationship. Hypotheses tested the ways that participants’ use of adjectives, of active and passive linguistic structures, and of phrases that make connections between events related to levels of conflict, perceptions of agency, and different styles of thinking about positive and negative events. Past studies have shown that negative events prompt more cognitive analyses than do positive or neutral events; the current study demonstrated this linguistically. Conjunct adverbial phrases—those phrases that draw causal connections, comparisons, and contrasts between events—appeared more frequently in the negative stories about arguments than in the positive stories about bonding. Similarly, more causal explanations appeared in conflict stories than in bonding stories. Other hypothesized relationships were not supported by the data. Qualitative analyses revealed that only mothers employed non-literal tropes in their stories, and they usually did so when trying to offer analyses about their daughters. A second pattern established that participants used the word “we” more in bonding stories than in conflict stories and that, in conflict stories, they used an abundance of singular pronouns while describing the argument but shifted to the word “we” when describing the resolution. Overall, research of natural language is a promising but inchoate line of study; thus, replications of the current study as well as the design of new, similar studies would be highly beneficial. Such studies may offer greater insight into the assessment and treatment of clients in a psychotherapeutic setting.
Law and Order: The Effects of Suspicion in the Courtroom
Cynthia H. Posner
Frequently, within a trial, the very instructions to disregard are themselves disregarded. In fact, research has demonstrated that when a judge declares a piece of evidence inadmissible, the jurors often pay more attention to that evidence than if it remained admissible—a phenomenon known as the backfire effect. Based on previous research suggesting that suspicion may serve as a counter to the fundamental attribution error, it was hypothesized that suspicion might play a role in the courtroom as a correctional bias countering the backfire effect. Over the course of a series of studies, in which mock jurors randomly assigned to a condition read through a trial transcript and completed a questionnaire about their verdicts, the possible roles and effects of suspicion were tested. The results demonstrate a replication of the backfire effect, and suggest that suspicion about the motives of why such evidence is introduced seems to be an antidote to this effect, bringing verdicts to the baseline level. Further, the results suggest that this suspicion can have this effect without in turn causing an alternative bias that would result in unfair verdicts in the opposite direction. And it appears from the data that suspicion is a remedy in both pro-prosecution and pro-defense instances. In addition, effects of the polygraph as a piece of critical evidence were explored and are discussed. The potential role of suspicion has powerful implications for maintaining justice within the system of law and the research serves as evidence...not to be disregarded.
Attributions in Parent-Teen Relationships: Do They Matter?
Natalie R. Tolejko
Research on attributional style has spawned extensive research on how people’s explanations of events are related to their moods and the quality of their intimate relationships. The role of attributions in parent-teen relationships has been largely ignored, thus the current study addressed the relationship between mothers’ personal attributional styles and their attributions for their children’s behavior as well as the correlations between their attributions about this behavior and their conflict levels and feelings of parental efficacy. Forty-eight mothers of 11 to 14 year old boys and girls completed measures of attributional style for hypothetical events in both their own and their children’s lives. Neuroticism, negative affect, conflict levels, and parenting efficacy were also measured. Finally, the CAVE technique was used to provide external ratings of short answer explanations for both real and hypothetical events. Results showed that the globality of a mother’s personal attributions for negative events predicts the globality of her attributions for events in her child’s life. Both the globality and stability of her attributions for her child’s negative behaviors predict conflict levels, and the stability of a mother’s attributions predicts her feelings of efficacy as a parent. The differences between various measures of attributions were tested, along with differences due to the teen’s gender. Finally, implications for future research and a model to guide such research are discussed.