Review on possible gravitational anomalies

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

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

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

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

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

Headache and adverse pregnancy outcomes: a prospective study

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Determination of micro-scale plastic strain caused by orthogonal cutting

An electron beam lithography technique has been used to produce microgrids in order to measure local plastic strains, induced during an orthogonal cutting process, at the microscopic scale in the shear zone and under the machined surface. Microgrids with a 10 μm pitch and a line width less than 1 μm have been printed on the polished surface of an aluminium alloy AA 5182 to test the applicability of the technique in metal cutting operations. Orthogonal cutting tests were carried out at 40 mm/s. Results show that the distortion of the grids could successfully be used to compute plastic strains due to orthogonal cutting with higher accuracy compared to other techniques reported in the literature. Strain maps of the machined specimens have been produced and show high-strain gradients very close to the machined surface with local values reaching 2.2. High-resolution strain measurements carried out in the primary deformation zone also provide new insight into the material deformation during the chip formation process

Type-and-Scope Safe Programs and Their Proofs

We abstract the common type-and-scope safe structure fromcomputations on lambda-terms that deliver, e.g., renaming, substitution, evaluation, CPS-transformation, and printing witha name supply. By exposing this structure, we can prove generic simulation and fusion lemmas relating operations built this way. This work has been fully formalised in Agda

Strong subadditivity and the covariant holographic entanglement entropy formula

Headrick and Takayanagi showed that the Ryu-Takayanagi holographic entanglement entropy formula generally obeys the strong subadditivity (SSA) inequality, a fundamental property of entropy. However, the Ryu-Takayanagi formula only applies when the bulk spacetime is static. It is not known whether the covariant generalization proposed by Hubeny, Rangamani, and Takayanagi (HRT) also obeys SSA. We investigate this question in three-dimensional AdS-Vaidya spacetimes, finding that SSA is obeyed as long as the bulk spacetime satisfies the null energy condition. This provides strong support for the validity of the HRT formula.Comment: 38 page

Determinant and Weyl anomaly of Dirac operator: a holographic derivation

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