16,779 research outputs found

    DNA extraction from formalin-fixed Franciscana tissues

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    The present paper reports the extraction of DNA from formalin-fixed Pontoporia blainvillei tissues. Following the Vachot and Monerot (1996) protocol, fragmented DNA (300-700bp) was extracted from more than 95% of liver and muscle samples. DNA yield in liver samples was significantly higher than in muscle samples (4.574 ± 1.169mg DNA/mg versus 0.808 ± 0.297mg DNA/mg). Similar results were obtained from nine other species of cetaceans and five species of pinnipeds. It is of special interest to have a method that allows the utilisation of museum specimens not originally preserved for genetic studies, which may include rarely available, declining or extinct species. SPANISH: El presente trabajo reporta la extracción de ADN a partir de tejidos formolizados de Pontoporia blainvillei. Siguiendo el protocolo de Vachot y Monerot (1996) se pudo extraer ADN degradado (300-700pb) en más del 95% de las muestras de hígado y músculo analizadas. El rendimiento en ADN fue significativamente mayor en muestras de hígado que en muestras de músculo (4.574 ± 1.169mg DNA/mg tejido húmedo versus 0.808 ± 0.297mg DNA/mg tejido húmedo). Resultados similares se obtuvieron en otras nueve especies de Cetáceos y cinco de Pinnípedos. Resulta de gran interés contar con un método que permita la utilización de especímenes depositados en museos y que no hayan sido originalmente colectados para estudios genéticos, incluyendo especies de difícil obtención, en franca declinación o extintas

    Star-formation in the central kpc of the starburst/LINER galaxy NGC1614

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    A high angular resolution, multi-wavelength study of the LINER galaxy NGC1614 has been carried out. OVRO CO 1-0 observations are presented together with extensive multi-frequency radio continuum and HI absorption observations with the VLA and MERLIN. Toward the center of NGC1614, we have detected a ring of radio continuum emission with a radius of 300 pc. This ring is coincident with previous radio and Paschen-alpha observations. The dynamical mass of the ring based on HI absorption is 3.1 x 10E9 Msun. The peak of the integrated CO 1-0 emission is shifted by 1" to the north-west of the ring center and a significant fraction of the CO emission is associated with a crossing dust lane. An upper limit to the molecular gas mass in the ring region is 1.7 x 10E9 Msun. Inside the ring, there is a north to south elongated 1.4GHz radio continuum feature with a nuclear peak. This peak is also seen in the 5GHz radio continuum and in the CO. We suggest that the R=300 pc star forming ring represents the radius of a dynamical resonance - as an alternative to the scenario that the starburst is propagating outwards from the center into a molecular ring. The ring-like appearance probably part of a spiral structure. Substantial amounts of molecular gas have passed the radius of the ring and reached the nuclear region. The nuclear peak seen in 5GHz radio continuum and CO is likely related to previous star formation, where all molecular gas was not consumed. The LINER-like optical spectrum observed in NGC1614 may be due to nuclear starburst activity, and not to an Active Galactic Nucleus (AGN). Although the presence of an AGN cannot be excluded.Comment: Accepted by Astronomy and Astrophysics, 12 pages, 10 figure

    B747/JT9D flight loads and their effect on engine running clearances and performance deterioration; BCAC NAIL/P and WA JT9D engine diagnostics programs

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    Flight loads on the 747 propulsion system and resulting JT9D blade to outer airseal running clearances during representative acceptance flight and revenue flight sequences were measured. The resulting rub induced clearance changes, and engine performance changes were then analyzed to validate and refine the JT9D-7A short term performance deterioration model

    Duality in Shearing Rheology Near the Athermal Jamming Transition

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    We consider the rheology of soft-core frictionless disks in two dimensions in the neighborhood of the athermal jamming transition. From numerical simulations of bidisperse, overdamped, particles, we argue that the divergence of the viscosity below jamming is characteristic of the hard-core limit, independent of the particular soft-core interaction. We develop a mapping from soft-core to hard-core particles that recovers all the critical behavior found in earlier scaling analyses. Using this mapping we derive a duality relation that gives the exponent of the non-linear Herschel-Bulkley rheology above jamming in terms of the exponent of the diverging viscosity below jamming.Comment: 5 pages, 4 figures. Manuscript revisions: new title, additional text concerning connections to experiment, revised Fig. 4, other minor changes and clarifications in text. Conclusions remain essentially unchanged. Accepted for publication in Phys. Rev. Let

    Timelessly Present, Compassionately Impassible: A Defense of Two Classical Divine Attributes

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    This study articulates a God-concept in the tradition of classical Christian theism, contending with calls to modify significantly or revise classical constructions. Attention falls upon two closely related divine attributes that have, especially in recent decades, come under philosophical and theological attack – God’s timelessness and impassibility (inability to suffer). Is the “classical” Lord truly Immanuel, i.e. with us? This general question motivates the study. The opening three chapters analyze aspects of the God-concepts put forth by Augustine, Aquinas, and Calvin. Apparent tensions between a timeless transcendence and an affirming union of the Trinity with creation are countenanced, with an eye to doing justice to both doctrines. Chapter One examines the idea of divine timelessness and corresponding thoughts about temporal reality found in the Confessions, supplementing Augustinian transcendence with the creational and eschatological insights of two other Church Fathers. Chapter Two documents Aquinas’s affirmation of both God’s strong immutability and the non-necessity of creation, while questioning whether he affirms these in a logically consistent way. Chapter Three then follows the contours of Calvin’s Trinitarianism and Christology, reflecting on the Triune Creator’s gracious “wedding” of himself to the whole work of creation. The final three chapters operate within the fields of philosophy and philosophical theology. Chapter Four commends a tenseless (or B) theory of time, highlighting several problems surrounding tensed (or A) theories of time. But this former view implies that there is no “official present,” leaving no apparent room for the presence of the timeless God with times and temporally located agents. Thus Chapter Five seeks to address classical eternalism’s “present problem.” The conclusion is reached that the temporally absent God’s “present problem” can be resolved by embracing a “risk-free” understanding of divine providence, best understood in terms of a “Reformed decree” that strongly actualizes all non-divine entities and events. Chapter Six begins by wrestling with what implications the timelessness doctrine might have for “responsive” divine compassion and ends by proposing that the infinite God “embraces” the finite world not by way of a panentheistic inclusion but in some ways more akin to a husband’s attentive care for his wife

    Two phase transitions in the fully frustrated XYXY model

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    The fully frustrated XYXY model on a square lattice is studied by means of Monte Carlo simulations. A Kosterlitz-Thouless transition is found at TKT0.446T_{\rm KT} \approx 0.446, followed by an ordinary Ising transition at a slightly higher temperature, Tc0.452T_c \approx 0.452. The non-Ising exponents reported by others, are explained as a failure of finite size scaling due to the screening length associated with the nearby Kosterlitz-Thouless transition.Comment: REVTEX file, 8 pages, 5 figures in uuencoded postscrip

    Unitary ambiguity in the extraction of the E2/M1 ratio for the γNΔ\gamma N\leftrightarrow\Delta transition

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    The resonant electric quadrupole amplitude in the transition γNΔ(1232)\gamma N\leftrightarrow\Delta(1232) is of great interest for the understanding of baryon structure. Various dynamical models have been developed to extract it from the corresponding photoproduction multipole of pions on nucleons. It is shown that once such a model is specified, a whole class of unitarily equivalent models can be constructed, all of them providing exactly the same fit to the experimental data. However, they may predict quite different resonant amplitudes. Therefore, the extraction of the E2/M1(γNΔ\gamma N\leftrightarrow\Delta) ratio (bare or dressed) which is based on a dynamical model using a largely phenomenological πN\pi N interaction is not unique.Comment: 10 pages revtex including 4 postscript figure

    Universal Behavior in Excited Heavy-Light and Light-Light Mesons

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    A common pattern of large orbital and radial excitations in heavy-light and light-light mesons is demonstrated. Within a general potential model the Regge slopes of the light degrees of freedom for these mesons are shown to be in the ratio of two. The possibility of ``tower'' degeneracy occurs only with pure scalar confinement.Comment: Latex, 10 pages, 2 figures placed using epsf.sty. Z-compressed postscript version available at http://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-970.ps.Z or at ftp://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-970.ps.
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