6,380 research outputs found

    On the genus "Asplenium" in the Iberian Peninsula"

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    The Asplenium species recorded from the Iberian peninsula comprise diploids and tetraploids, and of the latter, both auto- and allotetraploids occur. Evidence from the meiotic pairing behaviour of the chromosomes in synthetic hybrids is adduced to show how the mode of origin and interrelationships of such species can be elucidated, and specific reference is made to Asplenium foresiense, A. majoricum, A. petrarchae and A. billotii. The suggested occurrence of autopolyploidy in Asplenium cuneifolium is also discussed. Evidence is presented which shows that in the British Isles and Corsica serpentine plants previously regarded as autotetraploid derivatives of A. cuneifolium are in fact allotetraploid and almost certainly just specialized serpentine forms of Asplenium adiantum-nigrum. It is suggested that such forms of A. adiantum-nigrum could occur also on serpentine rocks elsewhere in western Europe, for example, in Spain and France.Las especies del genero Asplenium, registradas en la Peninsula Ibérica, comprenden citotipos diploides y tetraploides, siendo estos últimos tanto autotetraploides como alotetraploides. Del apareamiento miótico de los cromosomas en los híbridos sintéticos se aducen pruebas para mostrar como se pueden dilucidar el modo de origen y las interrelaciones de tales especies, y se hace referencia específica a Asplenium foresiense, A. majoricum, A. petrarchae y A. billotii. También se discute la cuestión de la autopoliploidía de A. cuneifolium que habia sido sugerida previamente. Se ofrecen datos experimentales que muestran que en las Islas Británicas y en Córcega las plantas que crecen sobre serpentinas, anteriormente consideradas como un derivado autotetraploidal de A. cuneifolium, son en realidad alotetraploides y, casi con certeza, no son más que formas serpentinícolas especializadas de A. adiantum-nigrum. Se sugiere que tales formas de A. adiantum-nigrum pueden existir también sobre serpentinas en otras partes de Europa occidental, por ejemplo, en España o Francia

    Flexurally-resisted uplift of the Tharsis Province, Mars

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    The tectonic style of Mars is dominated by vertical motion, perhaps more than any of the terrestrial planets. The imprint of this tectonic activity has left a surface widely faulted even though younger volcanism has masked the expression of tectonism in many places. Geological activity associated with the Tharsis and, to a lesser extent, Elysium provinces is responsible for a significant portion of this faulting, while the origins of the remaining features are enigmatic in many cases. The origin and evolution of the Tharsis and Elysium provinces, in terms of their great elevation, volcanic activity, and tectonic style, has sparked intense debate over the last fifteen years. Central to these discussions are the relative roles of structural uplift and volcanic construction in the creation of immense topographic relief. For example, it is argued that the presence of very old and cratered terrain high on the Tharsis rise, in the vicinity of Claritas Fossae, points to structural uplift of an ancient crust. Others have pointed out, however, that there is no reason that this terrain could not be of volcanic origin and thus part of the constructional mechanism

    Impact production of NO and reduced species

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    It has recently been suggested that a reported spike in seawater (87)Sr/(86)Sr at the K-T boundary is the signature of an impact-generated acid deluge. However, the amount of acid required is implausibly large. Some about 3 x 10 to the 15th power moles of Sr must be weathered from silicates to produce the inferred Sr spike. The amount of acid required is at least 100 and probably 1000 times greater. Production of 3 x 10 to the 18th power moles of NO is clearly untenable. The atmosphere presently contains only 1.4 x 10 to the 20th power moles of N-sub 2 and 3.8 x 10 to the 19th power moles of O sub 2 If the entire atmosphere were shocked to 2000 K and cooled within a second, the total NO produced would be about 3 x 10 to the 18th power moles. This is obviously unrealistic. A (still to short) cooling time of 10th to the 3rd power sec reduces NO production by an order of magnitude. In passing, we note that if the entire atmosphere had in fact been shocked to 2000 K, acid rain would have been the least of a dinosaur's problems. Acid rain as a mechanism poses poses other difficulties. Recently deposited carbonates would have been most susceptable to acid attack. The researchers' preferred explanation is simply increased continental erosion following ecological trauma, coupled with enchanced levels of CO-sub 2

    The Stability of the orbits of Earth-mass planets in and near the habitable zones of known exoplanetary systems

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    We have shown that Earth-mass planets could survive in variously restricted regions of the habitable zones (HZs) of most of a sample of nine of the 93 main-sequence exoplanetary systems confirmed by May 2003. In a preliminary extrapolation of our results to the other systems, we estimate that roughly a third of the 93 systems might be able to have Earth-mass planets in stable, confined orbits somewhere in their HZs. Clearly, these systems should be high on the target list for exploration for terrestrial planets. We have reached this conclusion by launching putative Earth-mass planets in various orbits and following their fate with a mixed-variable symplectic integrator

    Prospects for Extrasolar "Earths" in Habitable Zones

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    We have shown that Earth-mass planets could survive in variously restricted regions of the habitable zones (HZs) of most of a sample of nine of the 102 main-sequence exoplanetary systems confirmed by 19 November 2003. In a preliminary extrapolation of our results to the other systems, we estimate that roughly a half of these systems could have had an Earth-mass planet confined to the HZ for at least the most recent 1000 Ma. The HZ migrates outwards during the main-sequence lifetime, and so this proportion varies with stellar age. About two thirds of the systems could have such a planet confined to the HZ for at least 1000 Ma at sometime during the main-sequence lifetime. Clearly, these systems should be high on the target list for exploration for terrestrial planets. We have reached this conclusion by launching putative Earth-mass planets in various orbits and following their fate with mixed-variable symplectic and hybrid integrators. Whether the Earth-mass planets could form in the HZs of the exoplanetary systems is an urgent question that needs further study.Comment: 7 pages, 2 figure

    Elaborating Borderline and Psychopathic Personality with the Computerized Adaptive Test of Personality Disorder in a Female Correctional Sample

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    Most of what we know about Psychopathic Personality Disorder (PPD) is based upon research with males. Considerably less research has examined female manifestations of the construct, however, some research suggests that Borderline Personality Disorder (BPD) may represent a female phenotypic expression of PPD, particularly among incarcerated offenders. The current study examined distinction and convergence between PPD and BPD. Utilizing a sample of 146 female correctional inmates as well as 109 female college students, the current study employed the Computerized Adaptive Test of Personality Disorder (CAT-PD) as well as other specific indices to explore the extent to which these two personality disorders overlap from a dimensional trait perspective, which the CAT-PD provides. Steiger’s T-tests were calculated to determine whether there was a difference in the magnitude of the correlations between CAT-PD traits and these two personality disorders. Hierarchical linear regression analysis were also conducted to determine whether additional traits could augment the prediction of these two personality disorders beyond the selected traits in the DSM-5 alternative trait model, located in Section III of the DSM-5. Implications of these results in light of explaining the overlap between BPD and PPD among females are explained

    Pulling down their breaches : An analysis of Centrelink breach and appeal numbers from 1996 to 2001 using a case study of a single Centrelink office

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    This thesis is about current Centrelink breach and appeal figures. It is also about the current conservative neo-liberalising climate of Australian social policy reforms, with which they are inextricably connected. It shows that while Centrelink breach numbers have increased more than three fold since 1996, formal appeals against Centrelink decisions have not increased similarly. This thesis asks: what might this mean? It answers this question through a single case study of a Centrelink office. Data was collected using individual focused interviews, documents collected from the site, and direct observation (including a map of the office drawn by the researcher). Various possible interpretations drawn from the social policy literature were evaluated in relation to the case study findings. Interpretations included the neo-liberals, advocates, new-contractualism, the view that surveillance is oppressive and an interpretation that draws from the work of Michel Foucault. The thesis found that Foucault\u27s work on discipline and governmentality - particularly his ideas about surveillance and individualisation-was the most relevant interpretation of Centrelink breaching and appeals to the case study data. Much evidence was found for these governing techniques, and their imperfection. The thesis concludes that the current conservative neo-liberal based reforms, including the new breach regime, show undue confidence about their ability to govern individual Centrelink clients

    Fluorescent probes of the orientation of myosin regulatory light chains in relaxed, rigor, and contracting muscle.

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    The orientation of the light-chain region of myosin heads in relaxed, rigor, and isometrically contracting fibers from rabbit psoas muscle was studied by fluorescence polarization. Cysteine 108 of chicken gizzard myosin regulatory light chain (cgRLC) was covalently modified with iodoacetamidotetramethylrhodamine (iodo-ATR). Native RLC of single glycerinated muscle fibers was exchanged for labeled cgRLC in a low [Mg2+] rigor solution at 30 degrees C. Troponin and troponin C removed in this procedure were replaced. RLC exchange had little effect on active force production. X-ray diffraction showed normal structure in rigor after RLC exchange, but loss of axial and helical order in relaxation. In isolated myofibrils labeled cgRLC was confined to the regions of the sarcomere containing myosin heads. The ATR dipoles showed a preference for orientations perpendicular to the fiber axis, combined with limited nanosecond rotational motion, in all conditions studied. The perpendicular orientation preference was more marked in rigor than in either relaxation or active contraction. Stretching relaxed fibers to sarcomere length 4 microns to eliminate overlap between actin- and myosin-containing filaments had little effect on the orientation preference. There was no change in orientation preference when fibers were put into rigor at sarcomere length 4.0 microns. Qualitatively similar results were obtained with ATR-labeled rabbit skeletal RLC

    Automatic Music Transcription with Convolutional Neural Networks using Intuitive Filter Shapes

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    This thesis explores the challenge of automatic music transcription with a combination of digital signal processing and machine learning methods. Automatic music transcription is important for musicians who can\u27t do it themselves or find it tedious. We start with an existing model, designed by Sigtia, Benetos and Dixon, and develop it in a number of original ways. We find that by using convolutional neural networks with filter shapes more tailored for spectrogram data, we see better and faster transcription results when evaluating the new model on a dataset of classical piano music. We also find that employing better practices shows improved results. Finally, we open-source our test bed for pre-processing, training, and testing the models to assist in future research
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