15,753 research outputs found

    A metaphysical consideration of nature

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    Thesis (Ph.D.)--Boston Universit

    Description of a new Crossidius LeConte (Coleoptera: Cerambycidae: Cerambycinae: Trachyderini) from southern Georgia with comments on its biology and unusual distribution

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    Crossidius grahami Morris and Wappes new species (Coleoptera: Cerambycidae) is described from the Ohoopee Dunes of southern Georgia. Comments are included on the new species’ biology and disjunct distribution compared to other species of Crossidius LeConte. Illustrations include: dorsal and lateral views of the primary types of C. grahami, its natural habitat, the known host plant (Chrysoma pauciflosculosa (Michx.) Greene (Asteraceae)), pupal chamber, and dorsal views of both sexes of Crossidius humeralis quadrivittata Penrose, 1974, considered its closest anatomical counterpart and nearest geographical relative

    Changing the name of the NBPF/DUF1220 domain to the Olduvai domain

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    We are jointly proposing a new name for a protein domain of approximately 65 amino acids that has been previously termed NBPF or DUF1220. Our two labs independently reported the initial studies of this domain, which is encoded almost entirely within a single gene family. The name Neuroblastoma Breakpoint Family (NBPF) was applied to this gene family when the first identified member of the family was found to be interrupted in an individual with neuroblastoma. Prior to this discovery, the PFAM database had termed the domain DUF1220, denoting it as one of many protein domains of unknown function. It has been PFAM’s intention to use “DUF” nomenclature to serve only as a temporary placeholder until more appropriate names are proposed based on research findings. We believe that additional studies of this domain, primarily from our laboratories over the past 10 years, have resulted in furthering our understanding of these sequences to the point where proposing a new name for this domain is warranted. Because of considerable data linking the domain to human-specific evolution, brain expansion and cognition, we believe a name reflecting these findings would be appropriate. With this in mind, we have chosen to name the domain (and the repeat that encodes it) Olduvai. The gene family will remain as NBPF for now. The primary domain subtypes will retain their previously assigned names (e.g. CON1-3; HLS1-3), and the three-domain block that expanded dramatically in the human lineage will be termed the Olduvai triplet. The new name refers to Olduvai Gorge, which is a site in East Africa that has been the source of major anthropological discoveries in the early-mid 1900’s. We also chose the name as a tribute to the scientists who made important contributions to the early studies of human origins and our African genesis

    Modeling Disaster: The Failure of Management of the New England Groundfish Industry

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    Most of the worlds' marine fisheries are overexploited or endangered, including the New England groundfishery, once one of the world’s most prolific. After 35 years of management, stock sizes and catches are lower now than ever. We argue that New England groundfishermen are caught in a prisoner’s dilemma, from which they have failed to escape. We then suggest a set of policies to get these groudnfishermen out of their dilemma.Fishermen's dilemma, fishery management, New England fisheries

    Deconvolution of Images from BLAST 2005: Insight into the K3-50 and IC 5146 Star-forming Regions

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    We present an implementation of the iterative flux-conserving Lucy-Richardson (L-R) deconvolution method of image restoration for maps produced by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). Compared to the direct Fourier transform method of deconvolution, the L-R operation restores images with better-controlled background noise and increases source detectability. Intermediate iterated images are useful for studying extended diffuse structures, while the later iterations truly enhance point sources to near the designed diffraction limit of the telescope. The L-R method of deconvolution is efficient in resolving compact sources in crowded regions while simultaneously conserving their respective flux densities. We have analyzed its performance and convergence extensively through simulations and cross-correlations of the deconvolved images with available high-resolution maps. We present new science results from two BLAST surveys, in the Galactic regions K3-50 and IC 5146, further demonstrating the benefits of performing this deconvolution. We have resolved three clumps within a radius of 4'.5 inside the star-forming molecular cloud containing K3-50. Combining the well-resolved dust emission map with available multi-wavelength data, we have constrained the spectral energy distributions (SEDs) of five clumps to obtain masses (M), bolometric luminosities (L), and dust temperatures (T). The L-M diagram has been used as a diagnostic tool to estimate the evolutionary stages of the clumps. There are close relationships between dust continuum emission and both 21 cm radio continuum and ^(12)CO molecular line emission. The restored extended large-scale structures in the Northern Streamer of IC 5146 have a strong spatial correlation with both SCUBA and high-resolution extinction images. A dust temperature of 12 K has been obtained for the central filament. We report physical properties of ten compact sources, including six associated protostars, by fitting SEDs to multi-wavelength data. All of these compact sources are still quite cold (typical temperature below ~ 16 K) and are above the critical Bonner-Ebert mass. They have associated low-power young stellar objects. Further evidence for starless clumps has also been found in the IC 5146 region

    Improving the Convergence Properties of the Data Augmentation Algorithm with an Application to Bayesian Mixture Modeling

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    The reversible Markov chains that drive the data augmentation (DA) and sandwich algorithms define self-adjoint operators whose spectra encode the convergence properties of the algorithms. When the target distribution has uncountable support, as is nearly always the case in practice, it is generally quite difficult to get a handle on these spectra. We show that, if the augmentation space is finite, then (under regularity conditions) the operators defined by the DA and sandwich chains are compact, and the spectra are finite subsets of [0,1)[0,1). Moreover, we prove that the spectrum of the sandwich operator dominates the spectrum of the DA operator in the sense that the ordered elements of the former are all less than or equal to the corresponding elements of the latter. As a concrete example, we study a widely used DA algorithm for the exploration of posterior densities associated with Bayesian mixture models [J. Roy. Statist. Soc. Ser. B 56 (1994) 363--375]. In particular, we compare this mixture DA algorithm with an alternative algorithm proposed by Fr\"{u}hwirth-Schnatter [J. Amer. Statist. Assoc. 96 (2001) 194--209] that is based on random label switching.Comment: Published in at http://dx.doi.org/10.1214/11-STS365 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Making Photographs Speak

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    It has often been said that “a picture is worth a thousand words.” Making that picture spit out those mythical thousand words, as we can all attest, is no easy task. Over the course of the first half of the fall semester, the three of us were tasked with developing brief interpretive captions for two Civil War photographs each, with the end goal to display our work at the Civil War Institute’s 2019 Summer Conference. What initially appeared as a simple project quickly revealed itself to be a difficult, yet rewarding, challenge that taught us all important lessons concerning history, photography, and writing that we will not soon forget. Producing the photography exhibit enhanced our skills as historical writers, introduced us to the challenge of writing for a popular audience, and deepened our understanding of Civil War photography. [excerpt
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