800 research outputs found

    Graptolites et Chitinozoaires Siluriens de la vallée de la Burdinale, Massif du Brabant, Belgique

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    Assemblages of graptolites and chitinozoans are descnbed respectively by B. RICKARDS and J. VERNIERS from Silurian deposits which were studied in the Burdinale valley by J. VERNIERS (Ph. D. dissertation, 1976). These assemblages allow biostratigraphic zonations covering a time interval from late Llandovery to middle Wenlock

    Siluro-Devonian graptolite stratigraphy of the Catalonian Coastal Ranges

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    Two facies characterize the Silurian and lower Devonian of the Catalonian Coastal Ranges, namely euxinic and pelagic carbonate facies. The first, is represented by black shales in which the atavus, acinaces, cyphus, triangulatus, convolutus, ?sedgwickii, ellesae and tumescens zones have been recognized. The graptolite succesion is far from complete on present evidence, but this is probably due to unfavorable environmental (taphonomic) conditions. This facies is similar to that prevailing throughout the Iberian massif and most of western Europe. The pelagic carbonate facies is peculiar to the Pridoli and lower Devonian and corresponds to the facies type prevailing in the Western Mediterranean Area. It is characterized by the nodular texture of limestones and marls, with all gradations between nodular limestones, marls and slates. Massive nodular limestone, occur in the lower partof the sequence (La Creu Formation) while the alternation of limestones, marls and slates charaterizes the upper part (Olorda Formation). Orthoconic cephalopds, crinoids, conodonts and tentaculites are the most common fossils present; graptolites occur in some shale horizons in the lower part of the Olorda Formation. These graptolites give strong indications of the uniformis and hercynicus zones (Lochkovian). The uppermost part of the sequence has not provided any graptolite fauna, but according their dacrioconarid fauna it corresponds probably to the Pragian

    Siluro-Devonian graptolite stratigraphy of the Catalonian Coastal Ranges

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    Two facies characterize the Silurian and lower Devonian of the Catalonian Coastal Ranges, namely euxinic and pelagic carbonate facies. The first, is represented by black shales in which the atavus, acinaces, cyphus, triangulatus, convolutus, ?sedgwickii, ellesae and tumescens zones have been recognized. The graptolite succesion is far from complete on present evidence, but this is probably due to unfavorable environmental (taphonomic) conditions. This facies is similar to that prevailing throughout the Iberian massif and most of western Europe. The pelagic carbonate facies is peculiar to the Pridoli and lower Devonian and corresponds to the facies type prevailing in the Western Mediterranean Area. It is characterized by the nodular texture of limestones and marls, with all gradations between nodular limestones, marls and slates. Massive nodular limestone, occur in the lower partof the sequence (La Creu Formation) while the alternation of limestones, marls and slates charaterizes the upper part (Olorda Formation). Orthoconic cephalopds, crinoids, conodonts and tentaculites are the most common fossils present; graptolites occur in some shale horizons in the lower part of the Olorda Formation. These graptolites give strong indications of the uniformis and hercynicus zones (Lochkovian). The uppermost part of the sequence has not provided any graptolite fauna, but according their dacrioconarid fauna it corresponds probably to the Pragian

    The political power of twitter

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    In June 2016, the British voted by 52 per cent to leave the EU, a club the UK joined in 1973. This paper examines Twitter public and political party discourse surrounding the BREXIT withdrawal agreement. In particular, we focus on tweets from four different BREXIT exit strategies known as “Norway”, “Article 50”, the “Backstop” and “No Deal” and their effect on the pound and FTSE 100 index from the period of December 10th 2018 to February 24th 2019. Our approach focuses on using a Naive Bayes classification algorithm to assess political party and public Twitter sentiment. A Granger causality analysis is then introduced to investigate the hypothesis that BREXIT public sentiment, as measured by the twitter sentiment time series, is indicative of changes in the GBP/EUR Fx and FTSE 100 Index. Our results from the Twitter public sentiment indicate that the accuracy of the “Article 50” scenario had the single biggest effect on short run dynamics on the FTSE 100 index, additionally the “Norway” BREXIT strategy has a marginal effect on the FTSE 100 index whilst there was no significant causation to the GBP/EUR Fx. The BREXIT Political party sentiment for the “No Deal” was indicative of short term dynamics on the GBP/EUR Fx at a marginal rate. Our test concluded that there was no causality on the FTSE 100

    Cerebrovascular Hemodynamics during Concentric and Eccentric Phases of Heavy Resistance Exercise

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    Rapid and drastic fluctuations in arterial blood pressures, such as those occurring during heavy resistance exercise pose a unique challenge to the maintenance of cerebral perfusion. During high-intensity leg cycling, regulation of cerebral perfusion is reduced by rapid decreases in beat-to-beat fluctuations in blood pressure (diastolic phase) rather than rapid increases (systolic phase). The purpose of this study was to test the hypothesis that rhythmic heavy resistance exercise will similarly impair the regulation of cerebral blood flow during the diastolic phase of beat-to-beat fluctuations in pressure. We studied seven healthy male subjects. Beat-to-beat finger arterial pressures, and middle cerebral artery blood velocity (MCAv) were measured during 10 repetitions (REP) of rhythmic high intensity leg press exercise. Velocities and arterial pressures were evaluated during both the isotonic concentric and eccentric phases of each REP. The Gosling pulsatility index (PI) of MCAv of each REP was calculated as MCAv systolic-MCAv diastolic/MCAv mean. During the concentric phase, systolic arterial pressures progressively increased from REP 1 through REP 10 (P \u3c 0.001), while systolic MCAv was not different across all REPs (P \u3e0.2). Diastolic arterial pressures during the eccentric phase also increased from REP 1 through REP 10 (P = 0.03) however diastolic MCAv decreased during REPs 7-10 compared with REP 2 (P ≀ 0.02). MCAv PI also increased during REP 7-10 compared to REP 2 (P ≀ 0.02). Similar to high-intensity leg cycling, our data suggest that during rhythmic high-intensity leg press exercise, cerebral perfusion is well controlled during periods of rapid increases in blood pressure, but regulation of cerebral perfusion is impaired during the diastolic phase of beat-to-beat fluctuations in pressure

    Californian Science Students' Perceptions of their Classoom Learning Environments.

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    This study utilised the What Is Happening In this Class (WIHIC) questionnaire to examine factors that influence Californian student perceptions of their learning environment. Data were collected from 665 USA middle school science students in 11 Californian schools. Several background variables were included in the study to investigate their effects on students’ perceptions, such as student and teacher gender, student ethnic background and socio-economic status (SES), and student age. Class and school variables, such as class ethnic composition, class size and school socioeconomic status were also collected. A hierarchical analysis of variance was conducted to investigate separate and joint effects of these variables. Results from this study indicate that some scales of the WIHIC are more inclined to measure personal or idiosyncratic features of student perceptions of their learning environment whereas other scales contain more variance at the class level. Also, it was found that different variables affect different scale scores. A variable that consistently affected students' perceptions, regardless of the element of interest in the learning environment was student gender. Generally speaking girls perceived their learning environment more positively than did boys

    DUVET Survey: Mapping Outflows in the Metal-Poor Starburst Mrk 1486

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    We present a method to characterize star-formation driven outflows from edge-on galaxies and apply this method to the metal-poor starburst galaxy, Mrk 1486. Our method uses the distribution of emission line flux (from HÎČ\beta and [OIII] 5007) to identify the location of the outflow and measure the extent above the disk, the opening angle, and the transverse kinematics. We show that this simple technique recovers a similar distribution of the outflow without requiring complex modelling of line-splitting or multi-Gaussian components, and is therefore applicable to lower spectral resolution data. In Mrk 1486 we observe an asymmetric outflow in both the location of the peak flux and total flux from each lobe. We estimate an opening angle of 17−37∘17-37^{\circ} depending on the method and assumptions adopted. Within the minor axis outflows, we estimate a total mass outflow rate of ∌2.5\sim2.5 M⊙_{\odot} yr−1^{-1}, which corresponds to a mass loading factor of η=0.7\eta=0.7. We observe a non-negligible amount of flux from ionized gas outflowing along the edge of the disk (perpendicular to the biconical components), with a mass outflow rate ∌0.9\sim0.9 M⊙_{\odot} yr−1^{-1}. Our results are intended to demonstrate a method that can be applied to high-throughput, low spectral resolution observations, such as narrow band filters or low spectral resolution IFS that may be more able to recover the faint emission from outflows.Comment: 12 Pages, 6 Figure

    Changes in undergraduate student alcohol consumption as they progress through university

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    BACKGROUND: Unhealthy alcohol use amongst university students is a major public health concern. Although previous studies suggest a raised level of consumption amongst the UK student population there is little consistent information available about the pattern of alcohol consumption as they progress through university. The aim of the current research was to describe drinking patterns of UK full-time undergraduate students as they progress through their degree course. METHOD: Data were collected over three years from 5895 undergraduate students who began their studies in either 2000 or 2001. Longitudinal data (i.e. Years 1–3) were available from 225 students. The remaining 5670 students all responded to at least one of the three surveys (Year 1 n = 2843; Year 2 n = 2219; Year 3 n = 1805). Results: Students reported consuming significantly more units of alcohol per week at Year 1 than at Years 2 or 3 of their degree. Male students reported a higher consumption of units of alcohol than their female peers. When alcohol intake was classified using the Royal College of Physicians guidelines [1] there was no difference between male and females students in terms of the percentage exceeding recommended limits. Compared to those who were low level consumers students who reported drinking above low levels at Year 1 had at least 10 times the odds of continuing to consume above low levels at year 3. Students who reported higher levels of drinking were more likely to report that alcohol had a negative impact on their studies, finances and physical health. Consistent with the reduction in units over time students reported lower levels of negative impact during Year 3 when compared to Year 1. CONCLUSION: The current findings suggest that student alcohol consumption declines over their undergraduate studies; however weekly levels of consumption at Year 3 remain high for a substantial number of students. The persistence of high levels of consumption in a large population of students suggests the need for effective preventative and treatment interventions for all year groups
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