763 research outputs found

    Review on possible gravitational anomalies

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    This is an updated introductory review of 2 possible gravitational anomalies that has attracted part of the Scientific community: the Allais effect that occur during solar eclipses, and the Pioneer 10 spacecraft anomaly, experimented also by Pioneer 11 and Ulysses spacecrafts. It seems that, to date, no satisfactory conventional explanation exist to these phenomena, and this suggests that possible new physics will be needed to account for them. The main purpose of this review is to announce 3 other new measurements that will be carried on during the 2005 solar eclipses in Panama and Colombia (Apr. 8) and in Portugal (Oct.15).Comment: Published in 'Journal of Physics: Conferences Series of the American Institute of Physics'. Contribution for the VI Mexican School on Gravitation and Mathematical Physics "Approaches to Quantum Gravity" (Playa del Carmen, Quintana Roo, Mexico, Nov. 21-27, 2004). Updates to this information will be posted in http://www.lsc-group.phys.uwm.edu/~xavier.amador/anomalies.htm

    Higher Education, Inequality and the Public Good in Four African Countries: Ghana, Kenya, Nigeria and South Africa: Report of Johannesburg Workshop, 22-24 May 2017

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    This report provides a synthesised overview of the deliberations of the Project Workshop held in Johannesburg, South Africa from 22 to 24 May 2017 for the Economic and Social Research Council (ESRC) Newton/National Research Foundation (NRF) funded project, Higher Education, Inequality and the Public Good in four African countries: Ghana, Kenya, Nigeria and South Africa. The Workshop had two main purposes. As the first face-to-face meeting of the project since its start-up in December 2016, it was designed to provide an opportunity for in-depth planning by the full, cross-country research team, particularly towards the refinement of the research steps and instruments, as well as the further development of the first set of research outputs. In addition, the Workshop was structured to include on the second day a Stakeholder Workshop. This day was aimed at bringing together key higher education stakeholders from the participating countries to engage with them around the conceptual and contextual framing of the project and to strengthen the research design. The three days were therefore designed to enable more in-depth planning for going forward with the project and to begin to facilitate stakeholder involvement in the research. This report is aimed at providing an overview of the proceedings over the three days and, most importantly, drawing out the emerging issues from the Workshop for the project. It is therefore intended as both a record of key milestones within the project process and as a tool to assist in its further development and implementation. It has been organised into two main sections. The first discusses important themes that emerged out of the planning process and stakeholder engagement that are important for the project going forward, particularly towards deepening the conceptual thinking around the project, refining its research design and strengthening the planned research outputs. Discussion on and agreements reached on the next steps that need to be taken in the project are outlined in the second section. Attached to the report are also a number of appendices related to the workshop process and its outcomes

    Patient?s perception of the events during and after Osteogenic Alveolar Distraction

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    Objective: The aim of the study was to evaluate the patient?s perception of the events during and after an osteogenic alveolar distraction (OAD) procedure Materials and Methods: A total of fifty-five (55) osteogenic alveolar distraction (OAD) procedures were performed in fifty (50) patients, who then were asked to answer ten (10) questions related to the treatment. Six (6) questions made reference to predefined values in a Visual Analogical Scale (VAS), three (3) questions could be answered by a predetermined answer, and only one (1) question had a free answer. Results: In 76% of cases, the patient?s description of the sensation felt during the surgery was good and bearable; 84% of the patients didn?t feel pain after surgery. 4% of the patients felt pain during the activation period and 58% of the patients described the sensation during the activation period as pressure, felt most commonly, at the end of the period, and for about 20 minutes (66.6 %). In these cases the most frequently used analgesic was Paracetamol. Also, 46% expressed having had some difficulty to activate the device, with 10% of them in need of extra help. The presence of the activation rod caused discomfort in 52%. Finally, 78% of the patients treated with OAD would undergo this procedure again if it was necessary. A bone graft was performed in 27 out of the 50 treated patients, with 70% of them describing the bone graft surgery as more painful than the OAD. Conclusion: The OAD technique had a high degree of acceptance among the treated patients, however, some details as the interference of the activation rod continue to disturb them. The acceptance of the OAD technique is much better when compared with bone graft surgery technique as a second treatment

    Conceptualising Higher Education and the Public Good in Ghana, Kenya, Nigeria, and South Africa

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    Higher education has been the object of policy attention in sub-Saharan Africa in recent years. It has been seen as key to unlocking the potential of the youth bulge, responding to the demands of a growing middle class and to transforming commodities-based economies into knowledge societies (World Bank 2009; Cloete, Maassen & Bailey 2015; Chuks, 2017). Yet despite significant expansions of enrolment – including widening participation by women, major barriers to access exist, reflecting inequalities based on class, gender, geographical location, ethnicity, religion, language and disability (AAI 2015; Morley & Lugg 2009; Morley & Croft, 2011). There are quality challenges in relation to teaching and learning, research, and governance. While some comment on a ’renaissance in African higher education’ (Higgs, 2016), and others on the effects and framings of colonial epistemicides (Nyamnjoh, 2012) key questions abound about relevance and power relations highlighting the need to decolonise the curriculum, structure, organisation and cultures of universities. The student protests in South Africa from 2015 highlighted problems of access and funding, but these are not isolated events. They expose an unresolved colonial legacy in these higher education systems. These processes raise questions not only of the public good relevance of higher education - beyond the obvious advantages conferred on those who manage to go to these institutions – but also of how higher education and its relationship with society may be conceptualised given these contexts (Lebeau and Milla, 2008; Mamdani, 2017). An overarching question is who is defining the public good and how? While many of the above issues are global e.g. universities throughout Latin America, Australasia, Asia and Europe are involved in similar debates and protests, this paper explores the relationship between higher education and the public good in the sub- Saharan African context through a consideration of some connections and disconnections. There appear to be two distinct ways in which higher education and the public good have been conceptualised are discussed. Firstly, higher education can be portrayed as instrumental in shaping a version of the public good where its qualifications, knowledge production, innovation, development of the professional classes, and expertise are perceived to lead to particular manifestations of public good, delineated as economic, social, political or cultural (McMahon 2009; Stiglitz 1999). The key arguments that underpin this conceptual framing speak to different levels of the public good, whether individual and community levels or the provision of ‘global public goods’ (Marginson 2007; 2013; Menashy 2009). However, a contrasting set of arguments portray the relationship between higher education and the public good as an intrinsic one, where the intellectual, physical and cultural experiences enabled through higher education express and enact the public good e.g. prejudice reduction, democratisation, critical thinking, active citizenship (Singh 2001; Calhoun 2006; Leibowitz, 2013; Marginson, 2011; Locatelli, 2017). Important here are considerations of the historical conjuncture that shapes experiences of higher education at a particular time and what these may mean. In considering the connections and disjunctures between these two formulations and the way writings on higher education in contemporary Africa have engaged with this debate, the paper makes an argument for discussing the importance of processes that link instrumental and intrinsic visions of higher education and the public good. The analysis of these from a rigorous review of literature leads to a delineation of some different views of time, space and evaluation. The paper argues that these contestations need to be read contextually. Higher education in sub-Saharan Africa has moved through phases, from the establishment of flagship national universities in the post-independence period for state bureaucracy formation (Teferra, 2017), to the emergence of developmental universities with a commitment to indigenising knowledge and benefiting marginalised populations, through more recent tendencies towards the marketisation of public institutions and the significant growth of the private sector (Assié-Lumumba & CODESRIA 2006; ADEA & AAU 2004; Coleman 1986; Mamdani, 2007; McCowan 2016). Appreciating these contextual factors in shaping the role and functioning of higher education and thus its relationship to the public good is a central theme in our analysis. We suggest that mainstream conceptualisations of higher education and the public good are underpinned by particular understandings of the nature and form of higher education and how knowledge is acquired, developed and disseminated – orientations that may be very far from the reality of highly unequal, socially stratified, and politically complex societies within which higher education is deeply embedded. Thus a reconceptualisation of the public is required by these contexts and some challenge to conceptualisations of the private, given the strong obligations of individuals to extended families, and the sharing of the benefits of higher education amongst their communities of origin. The paper concludes with a consideration of what may be important in conceptualising higher education and the public good in the African context and the value of such thinking for broader debates on the role of higher education

    Flowing Between Fermionic Fixed Points

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    We study holographic Wilsonian renormalization group flows for bulk spinor fields in AdS. We use this to compute the all-loop beta function for fermionic double trace operators in the dual conformal field theory.Comment: 21 pages. V2: Acknowledgement added; v3: Typo correcte

    Efficacy of frovatriptan versus other triptans in the acute treatment of menstrual migraine: pooled analysis of three double-blind, randomized, crossover, multicenter studies

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    The objective of this study was to review the efficacy and safety of frovatriptan (F) versus rizatriptan (R), zolmitriptan (Z) and almotriptan (A), in women with menstrually related migraine (IHS criteria) through a pooled analysis of three individual studies. Subjects with a history of migraine with or without aura were randomized to F 2.5 mg or R 10 mg (study 1), F or Z 2.5 mg (study 2), and F or A 12.5 mg (study 3). The studies had an identical multicenter, randomized, double-blind, crossover design. After treating three episodes of migraine in no more than 3 months with the first treatment, patients had to switch to the next treatment for other 3 months. 346 subjects formed intention-to-treat population of the main study; 280 of them were of a female gender, 256 had regular menses and 187 were included in the menstrual migraine subgroup analysis. Rate of pain free at 2, 4 and 24 h was 23, 52 and 67 % with F and 30, 61 and 66 % with comparators (P = NS). Pain relief episodes at 2, 4 and 24 h were 37, 60 and 66 % for F and 43, 55 and 61 % for comparators (P = NS). Rate of recurrence was significantly (P < 0.05) lower under F either at 24 h (11 vs. 24 % comparators) or at 48 h (15 vs. 26 % comparators). Number of menstrual migraine attacks associated with drug-related adverse events was equally low (P = NS) between F (5 %) and comparators (4 %)

    Via Hexagons to Squares in Ferrofluids: Experiments on Hysteretic Surface Transformations under Variation of the Normal Magnetic Field

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    We report on different surface patterns on magnetic liquids following the Rosensweig instability. We compare the bifurcation from the flat surface to a hexagonal array of spikes with the transition to squares at higher fields. From a radioscopic mapping of the surface topography we extract amplitudes and wavelengths. For the hexagon--square transition, which is complex because of coexisting domains, we tailor a set of order parameters like peak--to--peak distance, circularity, angular correlation function and pattern specific amplitudes from Fourier space. These measures enable us to quantify the smooth hysteretic transition. Voronoi diagrams indicate a pinning of the domains. Thus the smoothness of the transition is roughness on a small scale.Comment: 17 pages, 14 figure

    Determinant and Weyl anomaly of Dirac operator: a holographic derivation

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    We present a holographic formula relating functional determinants: the fermion determinant in the one-loop effective action of bulk spinors in an asymptotically locally AdS background, and the determinant of the two-point function of the dual operator at the conformal boundary. The formula originates from AdS/CFT heuristics that map a quantum contribution in the bulk partition function to a subleading large-N contribution in the boundary partition function. We use this holographic picture to address questions in spectral theory and conformal geometry. As an instance, we compute the type-A Weyl anomaly and the determinant of the iterated Dirac operator on round spheres, express the latter in terms of Barnes' multiple gamma function and gain insight into a conjecture by B\"ar and Schopka.Comment: 11 pages; new comments and references added, typos correcte

    F-Theorem without Supersymmetry

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    The conjectured F-theorem for three-dimensional field theories states that the finite part of the free energy on S^3 decreases along RG trajectories and is stationary at the fixed points. In previous work various successful tests of this proposal were carried out for theories with {\cal N}=2 supersymmetry. In this paper we perform more general tests that do not rely on supersymmetry. We study perturbatively the RG flows produced by weakly relevant operators and show that the free energy decreases monotonically. We also consider large N field theories perturbed by relevant double trace operators, free massive field theories, and some Chern-Simons gauge theories. In all cases the free energy in the IR is smaller than in the UV, consistent with the F-theorem. We discuss other odd-dimensional Euclidean theories on S^d and provide evidence that (-1)^{(d-1)/2} \log |Z| decreases along RG flow; in the particular case d=1 this is the well-known g-theorem.Comment: 34 pages, 2 figures; v2 refs added, minor improvements; v3 refs added, improved section 4.3; v4 minor improvement
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