5,948 research outputs found

    Witten's Invariants of Rational Homology Spheres at Prime Values of KK and Trivial Connection Contribution

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    We establish a relation between the coefficients of asymptotic expansion of trivial connection contribution to Witten's invariant of rational homology spheres and the invariants that T.~Ohtsuki extracted from Witten's invariant at prime values of KK. We also rederive the properties of prime KK invariants discovered by H.~Murakami and T.~Ohtsuki. We do this by using the bounds on Taylor series expansion of the Jones polynomial of algebraically split links, studied in our previous paper. These bounds are enough to prove that Ohtsuki's invariants are of finite type. The relation between Ohtsuki's invariants and trivial connection contribution is verified explicitly for lens spaces and Seifert manifolds.Comment: 32 pages, no figures, LaTe

    Patients' beliefs towards contingency management: target behaviours, incentives and the remote application of these interventions

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    Abstract: Introduction: Contingency management interventions are among the most efficacious psychosocial interventions in promoting abstinence from smoking, alcohol and substance use. The aim of this study was to assess the beliefs and objections towards contingency management among patients in UK‐based drug and alcohol services to help understand barriers to uptake and support the development and implementation of these interventions. Methods: The Service User Survey of Incentives was developed and implemented among patients (N = 181) at three UK‐based drug and alcohol treatment services. Descriptive analyses were conducted to ascertain positive and negative beliefs about contingency management, acceptability of different target behaviours, incentives and delivery mechanisms including delivering incentives remotely using technology devices such as mobile telephones. Results: Overall, 81% of participants were in favour of incentive programs, with more than 70% of respondents agreeing with the majority of positive belief statements. With the exception of two survey items, less than a third of participants agreed with negative belief statements. The proportion of participants indicating a neutral response was higher for negative statements (27%) indicating greater levels of ambiguity towards objections and concerns regarding contingency management. Discussion and Conclusions: Positive beliefs towards contingency management interventions were found, including high levels of acceptability towards a range of target behaviours, incentives and the use of technology devices to remotely monitor behaviour and deliver incentives. These findings have implications for the development and implementation of remote contingency management interventions within the UK drug treatment services

    The DEEP2 Redshift Survey: Lyman Alpha Emitters in the Spectroscopic Database

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    We present the first results of a search for Lyman-alpha emitters (LAEs) in the DEEP2 spectroscopic database that uses a search technique that is different from but complementary to traditional narrowband imaging surveys. We have visually inspected ~20% of the available DEEP2 spectroscopic data and have found nine high-quality LAEs with clearly asymmetric line profiles and an additional ten objects of lower quality, some of which may also be LAEs. Our survey is most sensitive to LAEs at z=4.4-4.9 and that is indeed where all but one of our high-quality objects are found. We find the number density of our spectroscopically-discovered LAEs to be consistent with those found in narrowband imaging searches. The combined, averaged spectrum of our nine high-quality objects is well fit by a two-component model, with a second, lower-amplitude component redshifted by ~420 km/s with respect to the primary Lyman-alpha line, consistent with large-scale outflows from these objects. We conclude by discussing the advantages and future prospects of blank-sky spectroscopic surveys for high-z LAEs.Comment: Accepted for publication in Ap

    Characterizing the Circumgalactic Medium of the Lowest-mass Galaxies: A Case Study of IC 1613

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    Using 10 sight lines observed with the Hubble Space Telescope/Cosmic Origins Spectrograph, we study the circumgalactic medium (CGM) and outflows of IC 1613, which is a low-mass (M_* ~ 10⁞ M_⊙), dwarf irregular galaxy on the outskirts of the Local Group. Among the sight lines, four are pointed toward UV-bright stars in IC 1613, and the other six sight lines are background QSOs at impact parameters from 6 kpc (<0.1R_(200)) to 61 kpc (0.6R_(200)). We detect a number of Si ii, Si iii, Si iv, C ii, and C iv absorbers, most of which have velocities less than the escape velocity of IC 1613 and thus are gravitationally bound. The line strengths of these ion absorbers are consistent with the CGM absorbers detected in dwarf galaxies at low redshifts. Assuming that Si ii, Si iii, and Si iv comprise nearly 100% of the total silicon, we find 3% (~8 × 10Âł M_⊙), 2% (~7 × 10Âł M_⊙), and 32%–42% [~(1.0–1.3) × 10⁔ M_⊙] of the silicon mass in the stars, interstellar medium, and within 0.6R_(200) of the CGM of IC 1613. We also estimate the metal outflow rate to be áč€_(out,Z) â©Ÿ 1.1 x 10⁻⁔ M_⊙ yr⁻Âč and the instantaneous metal mass loading factor to be η_Z ≄ 0.004, which are in broad agreement with available observation and simulation values. This work is the first time a dwarf galaxy of such low mass is probed by a number of both QSO and stellar sight lines, and it shows that the CGM of low-mass, gas-rich galaxies can be a large reservoir enriched with metals from past and ongoing outflows

    Embodied learning: Responding to AIDS in Lesotho's education sector

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    This is an Author's Accepted Manuscript of an article published in Children's Geographies, 7(1), 2009. Copyright @ 2009 Taylor & Francis, available online at: http://www.tandfonline.com/doi/abs/10.1080/14733280802630981.In contrast to pre-colonial practices, education in Lesotho's formal school system has historically assumed a Cartesian separation of mind and body, the disciplining of students' bodies serving principally to facilitate cognitive learning. Lesotho has among the highest HIV-prevalence rates worldwide, and AIDS has both direct and indirect impacts on the bodies of many children. Thus, students' bodies can no longer be taken for granted but present a challenge for education. Schools are increasingly seen as a key point of intervention to reduce young people's risk of contracting the disease and also to assist them to cope with its consequences: there is growing recognition that such goals require more than cognitive learning. The approaches adopted, however, range from those that posit a linear and causal relationship between knowledge, attitudes and practices (so-called ‘KAP’ approaches, in which the role of schools is principally to inculcate the pre-requisite knowledge) to ‘life skills programmes’ that advocate a more embodied learning practice in schools. Based on interviews with policy-makers and practitioners and a variety of documentary sources, this paper examines a series of school-based AIDS interventions, arguing that they represent a less radical departure from ‘education for the mind’ than might appear to be the case. The paper concludes that most interventions serve to cast on children responsibility for averting a social risk, and to ‘normalise’ aberrant children's bodies to ensure they conform to what the cognitively-oriented education system expects

    Fate of Zinc Oxide Nanoparticles Coated onto Macronutrient Fertilizers in an Alkaline Calcareous Soil

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    Citation: Milani, N., Hettiarachchi, G. M., Kirby, J. K., Beak, D. G., Stacey, S. P., & McLaughlin, M. J. (2015). Fate of Zinc Oxide Nanoparticles Coated onto Macronutrient Fertilizers in an Alkaline Calcareous Soil. Plos One, 10(5), 16. doi:10.1371/journal.pone.0126275Zinc oxide (ZnO) nanoparticles may provide a more soluble and plant available source of Zn in Zn fertilizers due to their greater reactivity compared to equivalent micron-or millimetresized (bulk) particles. However, the effect of soil on solubility, spatial distribution and speciation of ZnO nanoparticles has not yet been investigated. In this study, we examined the diffusion and solid phase speciation of Zn in an alkaline calcareous soil following application of nanoparticulate and bulk ZnO coated fertilizer products (monoammonium phosphate (MAP) and urea) using laboratory-based x-ray techniques and synchrotron-based mu-x-ray fluorescence (mu-XRF) mapping and absorption fine structure spectroscopy (mu-XAFS). Mapping of the soil-fertilizer reaction zones revealed that most of the applied Zn for all treatments remained on the coated fertilizer granule or close to the point of application after five weeks of incubation in soil. Zinc precipitated mainly as scholzite (CaZn2(PO4)(2)center dot 2H(2)O) and zinc ammonium phosphate (Zn(NH4)PO4) species at the surface of MAP granules. These reactions reduced dissolution and diffusion of Zn from the MAP granules. Although Zn remained as zincite (ZnO) at the surface of urea granules, limited diffusion of Zn from ZnO-coated urea granules was also observed for both bulk and nanoparticulate ZnO treatments. This might be due to either the high pH of urea granules, which reduced solubility of Zn, or aggregation (due to high ionic strength) of released ZnO nanoparticles around the granule/point of application. The relative proportion of Zn(OH)(2) and ZnCO3 species increased for all Zn treatments with increasing distance from coated MAP and urea granules in the calcareous soil. When coated on macronutrient fertilizers, Zn from ZnO nanoparticles (without surface modifiers) was not more mobile or diffusible compared to bulk forms of ZnO. The results also suggest that risk associated with the presence of ZnO NPs in calcareous soils would be the same as bulk sources of ZnO

    Problem-oriented policing in England and Wales: barriers and facilitators

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    Evidence shows that the application of problem-oriented policing can be effective in reducing a wide range of crime and public safety issues, but that the approach is challenging to implement and sustain. This article examines police perceptions and experiences regarding organisational barriers to and facilitators of the implementation and delivery of problem-oriented policing. Drawing on surveys of (n = 4141) and interviews with (n = 86) police personnel from 19 police forces in England and Wales, we identify five key barriers and facilitators to problem-oriented policing: leadership and governance, capacity, organisational structures and infrastructure, partnership working and organisational culture. These factors provide important indicators for what police organisations need to do, or need to avoid, if they are to successfully embed and deliver problem-oriented policing. The article generates critical information about the processes that drive change in police organisations and offers recommendations for police managers who may wish to implement or develop problem-oriented policing. The paper also proposes a research agenda aimed at addressing evidence gaps in our understanding of the implementation and sustenance of problem-oriented policing

    A unified Witten-Reshetikhin-Turaev invariant for integral homology spheres

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    We construct an invariant J_M of integral homology spheres M with values in a completion \hat{Z[q]} of the polynomial ring Z[q] such that the evaluation at each root of unity \zeta gives the the SU(2) Witten-Reshetikhin-Turaev invariant \tau_\zeta(M) of M at \zeta. Thus J_M unifies all the SU(2) Witten-Reshetikhin-Turaev invariants of M. As a consequence, \tau_\zeta(M) is an algebraic integer. Moreover, it follows that \tau_\zeta(M) as a function on \zeta behaves like an ``analytic function'' defined on the set of roots of unity. That is, the \tau_\zeta(M) for all roots of unity are determined by a "Taylor expansion" at any root of unity, and also by the values at infinitely many roots of unity of prime power orders. In particular, \tau_\zeta(M) for all roots of unity are determined by the Ohtsuki series, which can be regarded as the Taylor expansion at q=1.Comment: 66 pages, 8 figure

    Fake news and critical thinking in information evaluation

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    In the post-truth era we are constantly bombarded with “news” which is fabricated, distorted, and massaged information, published with the intention to deceive and mislead others. Such “news” has come to be known as “fake news”. The influence of fake news can have profound socio-political and cultural effects when translated into action. The ability to distinguish between real facts, fabricated stories, rumours, propaganda, or opinions is of paramount importance. The rapid proliferation of information through social media is now the norm. In this paper we consider the challenge of preparing students, in developing skills for recognising mis-information, dis-information and mal-information. We argue that critical thinking for evaluating information should now be considered a basic literacy, equally important to literacy itself, as well as information and information technology literacies. In this paper we revisit Bloom’s taxonomy of cognitive skills and represent what a learner can achieve at each level. We customise the traditional moral and ethical concepts suggested by the US Content Subcommittee of the ImpactCS Steering Committee to flag the ethical concerns over mis-information, dis-information and mal-information. We report on current levels of awareness and practices at the authors’ five higher education institutions, and reveal varying levels of awareness of the significance of critical literacy and different practices in each location. The paper concludes with an outline of future work
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