16,989 research outputs found

    Letters to the Editor

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    Similarities in Evasive Behavior of Wolf Spiders (Araneae: Lycosidae), American Toads (Anura: Bufonidae) and Ground Beetles (Coleopterea: Carabidae)

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    (excerpt) While collecting newly metalnorphosed American toads, Bufo anlericanus Holbrook, we have observed that they exhibited evasive behavior similar to that of adults of the wolf spiders, Pardosa saxatilis (Hentz), Pirata insularis Emerton, Pirata arerzicola Emerton, Pirata piratica (Oliver), and adults of the ground beetle, Elaplrrus ruscarius Say. When pursued or disturbed, the spiders, beetles and toads ran across the pound rapidly for short distances (ca. 1-50 cm). They then stopped abruptly and remained motionless. If they were further pursued, this escape sequence was repeated in the same or another direction. Toads and spiders occasionally moved to shallow water to avoid capture. Spiders ran across the water surface whereas the toads swam partially submerged. N\u27e observed this resemblance in evasive behavior on numerous occasions at ponds on the south edge of Carbondale, Illinois (spiders and toads), 1 krn west of Grinnell, Iowa (spiders and toads), and 1.5 km west of Bloomington, Illinois (spiders, toads and beetles). (Specimens were collected for identification from the latter site.

    The ageing pancreas

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    Type 2 diabetes is historically associated with older adults, and glucose tolerance is known to decline with advancing age. During the course of natural ageing, changes in many peripheral tissues contribute to this deterioration of glucose homeostasis. Included in this process are changes to the structure and function of the pancreatic islets, which undergo deviation in endocrine responses to glycaemic challenge. Current knowledge about the changes seen in the ageing pancreas is reviewed here

    Taxation—Treasury Regulation Valuing Mutual Fund Shares for Estate Tax Purposes at the Replacement Cost Held Invalid

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    Cartwright v. United States, 323 F. Supp. 769 (W.D.N.Y. 1971)

    Interferometric data for a shock-wave/boundary-layer interaction

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    An experimental study of the axisymmetric shock-wave / boundary-layer strong interaction flow generated in the vicinity of a cylinder-cone intersection was conducted. The study data are useful in the documentation and understanding of compressible turbulent strong interaction flows, and are part of a more general effort to improve turbulence modeling for compressible two- and three-dimensional strong viscous/inviscid interactions. The nominal free stream Mach number was 2.85. Tunnel total pressures of 1.7 and 3.4 atm provided Reynolds number values of 18 x 10(6) and 36 x 10(6) based on model length. Three cone angles were studied giving negligible, incipient, and large scale flow separation. The initial cylinder boundary layer upstream of the interaction had a thickness of 1.0 cm. The subsonic layer of the cylinder boundary layer was quite thin, and in all cases, the shock wave penetrated a significant portion of the boundary layer. Owing to the thickness of the cylinder boundary layer, considerable structural detail was resolved for the three shock-wave / boundary-layer interaction cases considered. The primary emphasis was on the application of the holographic interferometry technique. The density field was deduced from an interferometric analysis based on the Able transform. Supporting data were obtained using a 2-D laser velocimeter, as well as mean wall pressure and oil flow measurements. The attached flow case was observed to be steady, while the separated cases exhibited shock unsteadiness. Comparisons with Navier-Stokes computations using a two-equation turbulence model are presented

    Diastereodivergent synthesis of chiral tetrahydropyrrolodiazepinediones via a one-pot intramolecular aza-Michael/lactamization sequence

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    A modular and diastereodivergent synthesis of tetrahydro-1H-pyrrolo[1,2d]diazepine-(2,5)-diones is presented. The tetrahydropyrrolodiazepinedione scaffold is obtained via a base-mediated three-step isomerization/tandem cyclization of amino acid-coupled homoallylic amino esters. Diastereoselectivity of the process is mediated by the interplay of a kinetic cyclization event and a propensity for thermodynamic epimerization at two labile chiral centers, giving rise to two distinct major diastereomers dependent on starting material stereochemistry and reaction conditions selected. Herein, we present a synthetic and computational study for this tandem process on a variety of amino ester substrates.Work at the BU-CMD is supported by R24GM111625. The authors wish to thank Dr. Jeffrey Bacon for assistance with Xray crystallographic analysis, Dr. Norman Lee for assistance with high-resolution mass spectrometry analysis, and Dr. Paul Ralifo for assistance with NMR analysis. NMR (CHE-0619339) and MS (CHE-0443618) facilities at Boston University are supported by the NSF. (CHE-0619339 - NSF; CHE-0443618 - NSF; R24GM111625)Published versionSupporting documentationAccepted manuscrip

    The interconnectedness of ageing:does the convoy principal apply?

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    This is an excerpt from the content: The convoy principal states that any system is only as functional as its ‘slowest’ unit. As organisms are made up of interconnected networks of physiological systems, it is possible that this principle applies to the biology of ageing. Often biogerontology will focus either on organismal ageing (mechanisms associated with increased longevity of a lower model organism for example), ageing of an individual organ system (such as the cardiovascular/musculoskeletal/immune) or ageing at the cellular level (from telomere length to cellular senescence, with many different cell types being studied) without considering the interconnectedness between the three and importantly, between the separate units of the convoy; the different organ systems. Conceptually, research that aims to identify ‘anti-ageing’ therapies is often deemed to be reaching for a panacea that will arrest or slow down the ageing process as a whole, whereas a more realistic aim is to first identify how we can improve the perfor ..

    Social justice themed sermons from civic-minded clergy can push churchgoers towards greater activism to improve racial equality

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    Religion plays an important role in the lives of many Americans. But what role does religion and religious institutions play in motivating Americans to participate in politics? In their new book, R. Khari Brown, Ronald E. Brown, and James S. Jackson look at the role the spiritual and political efforts made by churches to improve human rights. They find that Black Americans are more likely than White and Hispanic Americans to believe that religious institutions have a moral obligation towards human rights activism, but that all groups are more likely to engage in acts like protests if they attend worship settings where they hear sermons about social justice issues and the importance of political activism

    Cutting Posts and Poles for Profit

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    This publication provides guidance on harvesting timber for posts and poles. It includes suggestions to check with the farm forester for technical assistance, secure a market for the product before cutting, cut the post to the proper length with square-cut ends, and limb smoothly

    Detection of Single Ion Spectra by Coulomb Crystal Heating

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    The coupled motion of ions in a radiofrequency trap has been used to connect the frequency- dependent laser-induced heating of a sympathetically cooled spectroscopy ion with changes in the fluorescence of a laser-cooled control ion. This technique, sympathetic heating spectroscopy, is demonstrated using two isotopes of calcium. In the experiment, a few scattered photons from the spectroscopy ion are transformed into a large deviation from the steady-state fluorescence of the control ion. This allows us to detect an optical transition where the number of scattered photons is below our fluorescence detection limit. Possible applications of the technique to molecular ion spectroscopy are briefly discussed.Comment: 7 Pages,10 Figure
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