242 research outputs found

    Interview with Arthur Strout by Mike Hastings

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    Biographical NoteArthur Edward Strout was born in Rockland, Maine, on September 6, 1935, to Olive Mabel (Edwards) and Alfred Meserve Strout and grew up in Thomaston, Maine. His father, a graduate of Bowdoin College and Harvard Law School, was an attorney in Rockland, Maine, and came from an established Maine family. His mother, the daughter of English immigrants, worked at the Registry of Deeds and later was a homemaker. After attending Thomaston schools, Arthur spent his final year of high school at Hebron Academy. He attended Bowdoin College (class of 1957), where he met George Mitchell. He earned his law degree in 1960 and then clerked for a judge in the 9th Circuit Court of Appeals. He worked for the Tax Division of the Department of Justice in Washington, D.C. and then went on to practice tax and finance law, returning to Maine in 1972. His son Charles also attended Bowdoin College and worked as a Senate page during Mitchell’s tenure there. SummaryInterview includes discussion of: family and educational background; Claude Allen as school master at Hebron Academy; meeting Mitchell at Bowdoin; attending Bowdoin from 1953-1957 and the housing situation; academics at Bowdon; law school and practicing tax law; continued contact with Mitchell; son Charles’s working with Mitchell; current life in Boston; and reflections on Mitchell and his current activities

    Hope\u27s Village of San Luis Obispo Charging Cabinet

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    This paper will review the steps the students took to provide Hope\u27s Village of SLO with a new charging cabinet. Hope\u27s Village of SLO is a local non profit that provides support for the central coast homeless community. Becky Jorgensen, who leads the organization, reached out to the students expressing her want for a new cabinet that people could use to charge their phones and tablets. The students then conceptualized the design with the help of an architecture student, applied for and received funding from the Alliance Group, purchased all materials and built the cabinet. This paper will walk you through all the steps the students took to curate this project as well as the steps to build the cabinet in the event this senior project is repeated

    Ayurvedic herbal medicine and lead poisoning

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    Although the majority of published cases of lead poisoning come from occupational exposures, some traditional remedies may also contain toxic amounts of lead. Ayurveda is a system of traditional medicine that is native to India and is used in many parts of world as an alternative to standard treatment regimens. Here, we report the case of a 58-year-old woman who presented with abdominal pain, anemia, liver function abnormalities, and an elevated blood lead level. The patient was found to have been taking the Ayurvedic medicine Jambrulin prior to presentation. Chemical analysis of the medication showed high levels of lead. Following treatment with an oral chelating agent, the patient's symptoms resolved and laboratory abnormalities normalized. This case highlights the need for increased awareness that some Ayurvedic medicines may contain potentially harmful levels of heavy metals and people who use them are at risk of developing associated toxicities

    Raman scattering in C_{60} and C_{48}N_{12} aza-fullerene: First-principles study

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    We carry out large scale {\sl ab initio} calculations of Raman scattering activities and Raman-active frequencies (RAFs) in C48N12{\rm C}_{48}{\rm N}_{12} aza-fullerene. The results are compared with those of C60{\rm C}_{60}. Twenty-nine non-degenerate polarized and 29 doubly-degenerate unpolarized RAFs are predicted for C48N12{\rm C}_{48}{\rm N}_{12}. The RAF of the strongest Raman signal in the low- and high-frequency regions and the lowest and highest RAFs for C48N12{\rm C}_{48}{\rm N}_{12} are almost the same as those of C60{\rm C}_{60}. The study of C60{\rm C}_{60} reveals the importance of electron correlations and the choice of basis sets in the {\sl ab initio} calculations. Our best calculated results for C60{\rm C}_{60} with the B3LYP hybrid density functional theory are in excellent agreement with experiment and demonstrate the desirable efficiency and accuracy of this theory for obtaining quantitative information on the vibrational properties of these molecules.Comment: submitted to Phys.Rev.

    Electron affinities of the first- and second- row atoms: benchmark ab initio and density functional calculations

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    A benchmark ab initio and density functional (DFT) study has been carried out on the electron affinities of the first- and second-row atoms. The ab initio study involves basis sets of spdfghspdfgh and spdfghispdfghi quality, extrapolations to the 1-particle basis set limit, and a combination of the CCSD(T), CCSDT, and full CI electron correlation methods. Scalar relativistic and spin-orbit coupling effects were taken into account. On average, the best ab initio results agree to better than 0.001 eV with the most recent experimental results. Correcting for imperfections in the CCSD(T) method improves the mean absolute error by an order of magnitude, while for accurate results on the second-row atoms inclusion of relativistic corrections is essential. The latter are significantly overestimated at the SCF level; for accurate spin-orbit splitting constants of second-row atoms inclusion of (2s,2p) correlation is essential. In the DFT calculations it is found that results for the 1st-row atoms are very sensitive to the exchange functional, while those for second-row atoms are rather more sensitive to the correlation functional. While the LYP correlation functional works best for first-row atoms, its PW91 counterpart appears to be preferable for second-row atoms. Among ``pure DFT'' (nonhybrid) functionals, G96PW91 (Gill 1996 exchange combined with Perdew-Wang 1991 correlation) puts in the best overall performance. The best results overall are obtained with the 1-parameter hybrid modified Perdew-Wang (mPW1) exchange functionals of Adamo and Barone [J. Chem. Phys. {\bf 108}, 664 (1998)], with mPW1LYP yielding the best results for first-row, and mPW1PW91 for second-row atoms. Indications exist that a hybrid of the type aa mPW1LYP + (1−a)(1-a) mPW1PW91 yields better results than either of the constituent functionals.Comment: Phys. Rev. A, in press (revised version, review of issues concerning DFT and electron affinities added

    A mathematical and computational review of Hartree-Fock SCF methods in Quantum Chemistry

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    We present here a review of the fundamental topics of Hartree-Fock theory in Quantum Chemistry. From the molecular Hamiltonian, using and discussing the Born-Oppenheimer approximation, we arrive to the Hartree and Hartree-Fock equations for the electronic problem. Special emphasis is placed in the most relevant mathematical aspects of the theoretical derivation of the final equations, as well as in the results regarding the existence and uniqueness of their solutions. All Hartree-Fock versions with different spin restrictions are systematically extracted from the general case, thus providing a unifying framework. Then, the discretization of the one-electron orbitals space is reviewed and the Roothaan-Hall formalism introduced. This leads to a exposition of the basic underlying concepts related to the construction and selection of Gaussian basis sets, focusing in algorithmic efficiency issues. Finally, we close the review with a section in which the most relevant modern developments (specially those related to the design of linear-scaling methods) are commented and linked to the issues discussed. The whole work is intentionally introductory and rather self-contained, so that it may be useful for non experts that aim to use quantum chemical methods in interdisciplinary applications. Moreover, much material that is found scattered in the literature has been put together here to facilitate comprehension and to serve as a handy reference.Comment: 64 pages, 3 figures, tMPH2e.cls style file, doublesp, mathbbol and subeqn package

    Modelling fast forms of visual neural plasticity using a modified second-order motion energy model

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    The Adelson-Bergen motion energy sensor is well established as the leading model of low-level visual motion sensing in human vision. However, the standard model cannot predict adaptation effects in motion perception. A previous paper Pavan et al.(Journal of Vision 10:1-17, 2013) presented an extension to the model which uses a first-order RC gain-control circuit (leaky integrator) to implement adaptation effects which can span many seconds, and showed that the extended model's output is consistent with psychophysical data on the classic motion after-effect. Recent psychophysical research has reported adaptation over much shorter time periods, spanning just a few hundred milliseconds. The present paper further extends the sensor model to implement rapid adaptation, by adding a second-order RC circuit which causes the sensor to require a finite amount of time to react to a sudden change in stimulation. The output of the new sensor accounts accurately for psychophysical data on rapid forms of facilitation (rapid visual motion priming, rVMP) and suppression (rapid motion after-effect, rMAE). Changes in natural scene content occur over multiple time scales, and multi-stage leaky integrators of the kind proposed here offer a computational scheme for modelling adaptation over multiple time scales. © 2014 Springer Science+Business Media New York

    Alu distribution and mutation types of cancer genes

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    Background: Alu elements are the most abundant retrotransposable elements comprising ~11% of the human genome. Many studies have highlighted the role that Alu elements have in genetic instability and how their contribution to the assortment of mutagenic events can lead to cancer. As of yet, little has been done to quantitatively assess the association between Alu distribution and genes that are causally implicated in oncogenesis.Results: We have investigated the effect of various Alu densities on the mutation type based classifications of cancer genes. In order to establish the direct relationship between Alus and the cancer genes of interest, genome wide Alu-related densities were measured using genes rather than the sliding windows of fixed length as the units. Several novel genomic features, such as the density of the adjacent Alu pairs and the number of Alu-Exon-Alu triplets, were developed in order to extend the investigation via the multivariate statistical analysis toward more advanced biological insight. In addition, we characterized the genome-wide intron Alu distribution with a mixture model that distinguished genes containing Alu elements from those with no Alus, and evaluated the gene-level effect of the 5\u27-TTAAAA motif associated with Alu insertion sites using a two-step regression analysis method.Conclusions: The study resulted in several novel findings worthy of further investigation. They include: (1) Recessive cancer genes (tumor suppressor genes) are enriched with Alu elements (p \u3c 0.01) compared to dominant cancer genes (oncogenes) and the entire set of genes in the human genome; (2) Alu-related genomic features can be used to cluster cancer genes into biological meaningful groups; (3) The retention of exon Alus has been restricted in the human genome development, and an upper limit to the chromosome-level exon Alu densities is suggested by the distribution profile; (4) For the genes with at least one intron Alu repeat in individual chromosomes, the intron Alu densities can be well fitted by a Gamma distribution; (5) The effect of the 5\u27-TTAAAA motif on Alu densities varies across different chromosomes

    Estimating genomic instability mediated by Alu retroelements in breast cancer

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    Alu-PCR is a relatively simple technique that can be used to investigate genomic instability in cancer. This technique allows identification of the loss, gain or amplification of gene sequences based on the analysis of segments between two Alu elements coupled with quantitative and qualitative analyses of the profiles obtained from tumor samples, surgical margins and blood. In this work, we used Alu-PCR to identify gene alterations in ten patients with invasive ductal breast cancer. Several deletions and insertions were identified, indicating genomic instability in the tumor and adjacent normal tissue. Although not associated with specific genes, the alterations, which involved chromosomal bands 1p36.23, 1q41, 11q14.3, 13q14.2, occurred in areas of well-known genomic instability in breast and other types of cancer. These results indicate the potential usefulness of Alu-PCR in identifying altered gene sequences in breast cancer. However, caution is required in its application since the Alu primer can produce non-specific amplification
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