131 research outputs found

    Ichthyological Bulletin of the J.L.B. Smith Institute of Ichthyology; No. 50

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    The publication of a new phase of research on the fishes of the Okavango drainage starts with this account which gives the valid names and broad distribution patterns of all species known from the system. Eighty species and subspecies are recognised, of which at least two (Parakneria fortuita Penrith; Serranochromis gracilis Greenwood) are endemic. Notes on early collections, synonymy, taxonomic status and distribution are given. New synonyms are recognized under Aplocheilichthys hutereaui (A. schalleri), Aplocheilichthys johnstoni (Haplochilus carlislei) and Ctenopoma multispinis (Ctenopoma machadoi) respectively. Recently published taxonomic changes are incorporated including two genera (Mesobola and Afromastacembelus), a species Serranochromis (Sargochromis) gracilis and the re-allocated Amphilius uranoscopus. The Zambezian Hemichromis species is re-identified as H. elongatus. A number of unresolved taxonomic problems are pointed out and certain dubious records are excluded from the checklist. The Okavango has a diverse fish fauna with tropical affinities. Many fish species are poorly studied. Man-induced threats to the continued natural functioning of this complex and dynamic system, especially large-scale water abstraction, overgrazing, deforestation and biocide spraying to eliminate tsetse fly, make it imperative that studies on the nature and role of the fishes are continued.Rhodes University Libraries (Digitisation

    Synthesis of a fullerene-based one-dimensional nanopolymer through topochemical transformation of the parent nanowire

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    Large-scale practical applications of fullerene (C60) in nanodevices could be significantly facilitated if the commercially-available micrometer-scale raw C60 powder were further processed into a one-dimensional (1D) nanowire-related polymer displaying covalent bonding as molecular interlinks and resembling traditional important conjugated polymers. However, there has been little study thus far in this area despite the abundant literature on fullerene. Here we report the synthesis and characterization of such a C60-based nanowire polymer, (-C60TMB-)n, where TMB=1,2,4-trimethylbenzene, which displays a well-defined crystalline structure, exceptionally large length-to-width ratio and excellent thermal stability. The material is prepared by first growing the corresponding nanowire through a solution phase of C60 followed by a topochemical polymerization reaction in the solid state. Gas chromatography, mass spectrometry and 13C nuclear magnetic resonance evidence is provided for the nature of the covalent bonding mode adopted by the polymeric chains. Theoretical analysis based on detailed calculations of the reaction energetics and structural analysis provides an in-depth understanding of the polymerization pathway. The nanopolymer promises important applications in biological fields and in the development of optical, electrical, and magnetic nanodevices.Comment: 30 pages, 12 figures, 2 table

    Electronic excitations in molecular solids:bridging theory and experiment

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    As the spatial and temporal resolution accessible to experiment and theory converge, computational chemistry is an increasingly powerful tool for modelling and interpreting spectroscopic data. However, the study of molecular processes, in particular those related to electronic excitations (e.g. photochemistry), frequently pushes quantum-chemical techniques to their limit. The disparity in the level of theory accessible to periodic and molecular calculations presents a significant challenge when modelling molecular crystals, since accurate calculations require a high level of theory to describe the molecular species, but must also take into account the influence of the crystalline environment on their properties. In this article, we briefly review the different classes of quantum-chemical techniques, and present an overview of methods that account for environmental influences with varying levels of approximation. Using a combination of solid-state and molecular calculations, we quantitatively evaluate the performance of implicit-solvent models for the [Ni(Et4dien)(η2-O,ON)(η1-NO2)] linkage-isomer system as a test case. We focus particularly on the accurate reproduction of the energetics of the isomerisation, and on predicting spectroscopic properties to compare with experimental results. This work illustrates how the synergy between periodic and molecular calculations can be exploited for the study of molecular crystals, and forms a basis for the investigation of more challenging phenomena, such as excited-state dynamics, and for further methodological developments

    Design programmes to maximise participant engagement: a predictive study of programme and participant characteristics associated with engagement in paediatric weight management.

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    BACKGROUND: Approximately 50% of paediatric weight management (WM) programme attendees do not complete their respective programmes. High attrition rates compromise both programme effectiveness and cost-efficiency. Past research has examined pre-intervention participant characteristics associated with programme (non-)completion, however study samples are often small and not representative of multiple demographics. Moreover, the association between programme characteristics and participant engagement is not well known. This study examined participant and programme characteristics associated with engagement in a large, government funded, paediatric WM programme. Engagement was defined as the family's level of participation in the WM programme. METHODS: Secondary data analysis of 2948 participants (Age: 10.44 ± 2.80 years, BMI: 25.99 ± 5.79 kg/m(2), Standardised BMI [BMI SDS]: 2.48 ± 0.87 units, White Ethnicity: 70.52%) was undertaken. Participants attended a MoreLife programme (nationwide WM provider) between 2009 and 2014. Participants were classified into one of five engagement groups: Initiators, Late Dropouts, Low- or High- Sporadic Attenders, or Completers. Five binary multivariable logistic regression models were performed to identify participant (n = 11) and programmatic (n = 6) characteristics associated with an engagement group. Programme completion was classified as ≄70% attendance. RESULTS: Programme characteristics were stronger predictors of programme engagement than participant characteristics; particularly small group size, winter/autumn delivery periods and earlier programme years (proxy for scalability). Conversely, participant characteristics were weak predictors of programme engagement. Predictors varied between engagement groups (e.g. Completers, Initiators, Sporadic Attenders). 47.1% of participants completed the MoreLife programme (mean attendance: 59.4 ± 26.7%, mean BMI SDS change: -0.15 ± 0.22 units), and 21% of those who signed onto the programme did not attend a session. CONCLUSIONS: As WM services scale up, the efficacy and fidelity of programmes may be reduced due to increased demand and lower financial resource. Further, limiting WM programme groups to no more than 20 participants could result in greater engagement. Baseline participant characteristics are poor and inconsistent predictors of programme engagement. Thus, future research should evaluate participant motives, expectations, and barriers to attending a WM programme to enhance our understanding of participant WM engagement. Finally, we suggest that session-by-session attendance is recorded as a minimum requirement to improve reporting transparency and enhance external validity of study findings

    Sedentary time in older men and women: an international consensus statement and research priorities

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    Sedentary time is a modifiable determinant of poor health, and in older adults, reducing sedentary time may be an important first step in adopting and maintaining a more active lifestyle. The primary purpose of this consensus statement is to provide an integrated perspective on current knowledge and expert opinion pertaining to sedentary behaviour in older adults on the topics of measurement, associations with health outcomes, and interventions. A secondary yet equally important purpose is to suggest priorities for future research and knowledge translation based on gaps identified. A five-step Delphi consensus process was used. Experts in the area of sedentary behaviour and older adults (n=15) participated in three surveys, an in-person consensus meeting, and a validation process. The surveys specifically probed measurement, health outcomes, interventions, and research priorities. The meeting was informed by a literature review and conference symposium, and it was used to create statements on each of the areas addressed in this document. Knowledge users (n=3) also participated in the consensus meeting. Statements were then sent to the experts for validation. It was agreed that self-report tools need to be developed for understanding the context in which sedentary time is accumulated. For health outcomes, it was agreed that the focus of sedentary time research in older adults needs to include geriatric-relevant health outcomes, that there is insufficient evidence to quantify the dose-response relationship, that there is a lack of evidence on sedentary time from older adults in assisted facilities, and that evidence on the association between sedentary time and sleep is lacking. For interventions, research is needed to assess the impact that reducing sedentary time, or breaking up prolonged bouts of sedentary time has on geriatric-relevant health outcomes. Research priorities listed for each of these areas should be considered by researchers and funding agencies

    The impact of the alkyne substitution pattern and metalation on the photo-isomerization of azobenzene-based platinum(II) diynes and polyynes

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    Trimethylsilyl-protected dialkynes incorporating azobenzene linker groups, Me<sub>3</sub>SiCî—ŒCRCî—ŒCSiMe<sub>3</sub> (R = azobenzene-3,3â€Č-diyl, azobenzene-4,4â€Č-diyl, 2,5-dioctylazobenzene-4,4â€Č-diyl), and the corresponding terminal dialkynes, HCî—ŒCRCî—ŒCH, have been synthesized and characterized. The CuI-catalyzed dehydrohalogenation reaction between <i>trans</i>-[Ph­(Et<sub>3</sub>P)<sub>2</sub>PtCl] and the deprotected dialkynes in a 2:1 ratio in <sup>i</sup>Pr<sub>2</sub>NH/CH<sub>2</sub>Cl<sub>2</sub> gives the platinum­(II) diynes <i>trans</i>-[Ph­(Et<sub>3</sub>P)<sub>2</sub>PtCî—ŒCRCî—ŒCPt­(PEt<sub>3</sub>)<sub>2</sub>Ph], while the dehydrohalogenation polycondensation reaction between <i>trans</i>-[(<sup>n</sup>Bu<sub>3</sub>P)<sub>2</sub>PtCl<sub>2</sub>] and the dialkynes in a 1:1 molar ratio under similar reaction conditions affords the platinum­(II) polyynes, [−Pt­(P<sup>n</sup>Bu<sub>3</sub>)<sub>2</sub>–Cî—ŒCRCî—ŒC−]<sub><i>n</i></sub>. The materials have been characterized spectroscopically, with the diynes also studied using single-crystal X-ray diffraction. The platinum­(II) diynes and polyynes are all soluble in common organic solvents. Optical-absorption measurements show that the compounds incorporating the <i>para</i>-alkynylazobenzene spacers have a higher degree of electronic delocalisation than their <i>meta</i>-alkynylazobenzene counterparts. Reversible photoisomerization in solution was observed spectroscopically for the alkynyl-functionalized azobenzene ligands and, to a lesser extent, for the platinum­(II) complexes. Complementary quantum-chemical modeling was also used to analyze the optical properties and isomerization energetics

    Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

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    Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius AA. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio

    1960: Abilene Christian College Lectures - Full Text

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    Table of Contents: Theme Speeches: Christian Faith in the Modern World Basis of Faith - Leonard Mullens - 9 Authority in Christianity - John T. Smithson, Jr. - 27 Origin and Preservation of the Bible - Neil R. Lightfoot - 44 Alleged Discrepancies of the Bible - David H. Bobo - 62 The Unity of the Bible - Jack Meyer - 91 Faith and Reason - Joe Sanders - 115 The Reasonableness of Supernaturalism - Virgil Trout - 126 The Present Statue of the Doctrine of Organic Evolution - J.D. Thomas - 146 The Nature of Man - Roy F. Osborne, Jr. - 181 Modern Challenges to Christian Morals - Carl Spain - 199 The Christ, Whose Son is He? - Gordon Teel - 232 Special Speeches Teaching the Word of God in Korea - L. Haskell Chessfire - 255 The Influence of Christian Education - Judge Jack Pope - 276 Mission Opportunities in the Far East - Harry Robert Fox - 288 Mission Work in Austria - Robert Skelton - 303 Report from Switzerland - Heinrich Blum - 313 The Work in Nigeria - Rees Byrant - 320 The Training of Evangelists in Foreign Fields - Reiner Kallus - 331 Christian Scholarships - Everett Ferguson - 340 Evangelizing the World - A.R. Holton - 349 Panel Discussions The Significance of the Dead Sea Scrolls The Scrolls and the Text of the Bible - Paul Rotenberry - 357 The Relation between the Religion of the Essenes and that of Early Christians - Jay Smith - 366 Biblical Interpretation Expediency and Pattern Authority - J.W. Roberts - 381 Examples in Pattern Authority - Thomas B. Warren - 392 Mental Health and Sin The Present State of Mental Health Knowledge - Donald R. Sime - 409 The Relationship of Mental Health Problems to Sin - Paul Easley - 421 The Teenager The Problems of Youth - Mack Wayne Craig - 432 Influences for Good - Wyatt Sawyer - 443 The Benefits of Abilene Christian College To the Church - Hulen Jackson - 451 To The Home - Robert S. Bell - 459 \u27To the Community - Louie Welch - 465 Expenses At Abilene Christian College - James C. Kerr - 469 The Graduate School at Abilene Christian College What I Am Getting Now in the ACC Graduate Program - Harold Vanderpool - 475 How the ACC Graduate Program Has Stood Up - Everett Ferguson - 481 What the ACC Graduate Program Ought To Be - Frank Pack - 486 The Importance to the Church of the ACC Graduate Program A.R. Holton - 490 Beware: Large File Size Uploaded by Jackson Hage

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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