10,711 research outputs found

    Professional Doctoral Study and Motherhood: A Critical Discourse Analysis

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    This study is a critical discourse analysis of professional doctorate study and motherhood drawn from the interview transcripts of 11 doctoral-student-mothers within a South London university. A lengthy review of contemporary motherhood and of motherhood and doctoral study was undertaken to understand the dominant societal forces legitimising the doctoral-student-mothers’ identity, to attend to the third objective of the study. In doing so, a hegemony of intensive mothering ideology was revealed as the ‘backdrop’ to contemporary mothering. A literature review on doctoral-student-motherhood revealed recurrent themes centred around a ‘complex identity,’ ‘juggling and struggling,’ ‘belonging’ and ‘emancipation.’ A Foucauldian critical discourse analysis was undertaken from a critical realist perspective, which revealed three dominant discourses being utilised by the doctoralstudent-mothers, these being synergy, activism and belonging and becoming. Analysis of these discourses revealed that within the discourse of synergy, the doctoral-student-mothers were functioning as servant leaders and were altering the distribution of housework in their families. The discourse of activism showed that the doctoral-student-mothers were using both scholarship and maternal identity to function as activists through their doctoral studies. The discourse of belonging and becoming showed the doctoral-student-mothers were experiencing imposter phenomenon and were using their doctorates for emancipatory purposes, more so than to add knowledge to their professional field. Discussion is interwoven into the analysis of the three dominant discourses. Recommendations for change and future research include a review of academic mentoring for doctoral-student-mothers, an analysis of the impact of the Covid-19 pandemic on doctoral student motherhood and an analysis of activism as a feature of doctoral-student-motherhood more broadly

    Selectivity in regeneration of the oculomotor nerve in the cichlid fish, Astronotus ocellatus

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    It has long been considered a general rule for nerve regeneration that the reinnervation of skeletal muscle is nonselective. Regenerating nerve fibers are supposed to reconnect with one skeletal muscle as readily as another according to studies covering a wide range of vertebrates (Weiss, 1937; Weiss & Taylor, 1944; Weiss & Hoag, 1946; Bernstein & Guth, 1961; Guth, 1961, 1962, 1963). Similarly, in embryogenesis proper functional connexions between nerve centers and particular muscles are supposedly attained, not by selective nerve outgrowth but rather through a process of ‘myotypic modulation’ (Weiss, 1955) that presupposes nonselective peripheral innervation. Doubt about the general validity of this rule and the concepts behind it has come from a series of studies on regeneration of the oculomotor nerve in teleosts, urodeles, and anurans and of spinal fin nerves in teleosts (Sperry, 1946, 1947, 1950, 1965; Sperry & Deupree, 1956; Arora & Sperry, 1957a, 1964)

    Mesomorphic properties of alkoxybenzylidene- aminoacetophenones

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    Liquid crystal phase transitions in compounds of alkoxybenzylidene-aminoacetophene serie

    On the NP-Hardness of Approximating Ordering Constraint Satisfaction Problems

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    We show improved NP-hardness of approximating Ordering Constraint Satisfaction Problems (OCSPs). For the two most well-studied OCSPs, Maximum Acyclic Subgraph and Maximum Betweenness, we prove inapproximability of 14/15+ϵ14/15+\epsilon and 1/2+ϵ1/2+\epsilon. An OCSP is said to be approximation resistant if it is hard to approximate better than taking a uniformly random ordering. We prove that the Maximum Non-Betweenness Problem is approximation resistant and that there are width-mm approximation-resistant OCSPs accepting only a fraction 1/(m/2)!1 / (m/2)! of assignments. These results provide the first examples of approximation-resistant OCSPs subject only to P ≠\neq \NP

    Brittle fracture of polymer transient networks

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    We study the fracture of reversible double transient networks, constituted of water suspensions of entangled surfactant wormlike micelles reversibly linked by various amounts of telechelic polymers. We provide a state diagram that delineates the regime of fracture without necking of the filament from the regime where no fracture or break-up has been observed. We show that filaments fracture when stretched at a rate larger than the inverse of the slowest relaxation time of the networks. We quantitatively demonstrate that dissipation processes are not relevant in our experimental conditions and that, depending on the density of nodes in the networks, fracture occurs in the linear viscoelastic regime or in a non-linear regime. In addition, analysis of the crack opening profiles indicates deviations from a parabolic shape close to the crack tip for weakly connected networks. We demonstrate a direct correlation between the amplitude of the deviation from the parabolic shape and the amount of non linear viscoelasticity

    Valuing mortality reductions in India : a study of compensating wage differentials

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    Conducting cost-benefit analyses of health and safety regulations requires placing a dollar value on reductions in health risks, including the risk of death. In the United States, mortality risks are often valued using compensating-wage differentials. These differentials measure what a worker would have to be paid to accept a small increase in his risk of death-which is assumed to equal what the worker would pay to achieve a small reduction in his risk of death. The authors estimate compensating-wage differentials for risk of fatal and nonfatal injuries in India's manufacturing industry. They estimate a hedonic wage equation using the most recent Occupational Wage Survey, supplemented by data on occupational injuries from the Indian Labour Yearbook. Their estimates of compensating-wage differentials imply a value of statistical life (VSL) in India of 6.4 million to 15 million 1990 rupees (roughly 150,000to150,000 to 360,000 at current exchange rates). This number is between 20 and 48 times forgone earnings-the human capital measure of the value of reducing the risk of death. The ratio of the VSL to forgone earnings implied by the study is larger than in comparable U.S. studies but smaller than the ratio implied by the only other compensating-wage study for India (Shanmugam 1997). The latter implies a ratio of VSL to forgone earnings of 73! The authors caution that in India, as in the United States, compensating-wage differentials in the labor market may overstate what individuals would themselves pay to reduce the risk of death. They suggest using their estimates as an upper boundon willingness to pay to reduce risk of death, and forgone earnings as a lower bound.Labor Policies,Water and Industry,Public Health Promotion,Environmental Economics&Policies,Banks&Banking Reform,Banks&Banking Reform,Health Monitoring&Evaluation,Health Economics&Finance,Water and Industry,Environmental Economics&Policies

    Implementation of higher-order absorbing boundary conditions for the Einstein equations

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    We present an implementation of absorbing boundary conditions for the Einstein equations based on the recent work of Buchman and Sarbach. In this paper, we assume that spacetime may be linearized about Minkowski space close to the outer boundary, which is taken to be a coordinate sphere. We reformulate the boundary conditions as conditions on the gauge-invariant Regge-Wheeler-Zerilli scalars. Higher-order radial derivatives are eliminated by rewriting the boundary conditions as a system of ODEs for a set of auxiliary variables intrinsic to the boundary. From these we construct boundary data for a set of well-posed constraint-preserving boundary conditions for the Einstein equations in a first-order generalized harmonic formulation. This construction has direct applications to outer boundary conditions in simulations of isolated systems (e.g., binary black holes) as well as to the problem of Cauchy-perturbative matching. As a test problem for our numerical implementation, we consider linearized multipolar gravitational waves in TT gauge, with angular momentum numbers l=2 (Teukolsky waves), 3 and 4. We demonstrate that the perfectly absorbing boundary condition B_L of order L=l yields no spurious reflections to linear order in perturbation theory. This is in contrast to the lower-order absorbing boundary conditions B_L with L<l, which include the widely used freezing-Psi_0 boundary condition that imposes the vanishing of the Newman-Penrose scalar Psi_0.Comment: 25 pages, 9 figures. Minor clarifications. Final version to appear in Class. Quantum Grav

    Blackbody radiation shift in a 43Ca+ ion optical frequency standard

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    Motivated by the prospect of an optical frequency standard based on 43Ca+, we calculate the blackbody radiation (BBR) shift of the 4s_1/2-3d_5/2 clock transition, which is a major component of the uncertainty budget. The calculations are based on the relativistic all-order single-double method where all single and double excitations of the Dirac-Fock wave function are included to all orders of perturbation theory. Additional calculations are conducted for the dominant contributions in order to evaluate some omitted high-order corrections and estimate the uncertainties of the final results. The BBR shift obtained for this transition is 0.38(1) Hz. The tensor polarizability of the 3d_5/2 level is also calculated and its uncertainty is evaluated as well. Our results are compared with other calculations.Comment: 4 page
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