A Check of a D=4 Field-Theoretical Calculation Using the High-Temperature Expansion for Dyson's Hierarchical Model

We calculate the high-temperature expansion of the 2-point function up to order 800 in beta. We show that estimations of the critical exponent gamma based on asymptotic analysis are not very accurate in presence of confluent logarithmic singularities. Using a direct comparison between the actual series and the series obtained from a parametrization of the form (beta_c -beta)^(-gamma) (Ln(beta_c -beta))^p +r), we show that the errors are minimized for gamma =0.9997 and p=0.3351, in very good agreement with field-theoretical calculations. We briefly discuss the related questions of triviality and hyperscalingComment: Uses Revtex, 27 pages including 13 figure

Universality, Scaling and Triviality in a Hierarchical Field Theory

Using polynomial truncations of the Fourier transform of the RG transformation of Dyson's hierarchical model, we show that it is possible to calculate very accurately the renormalized quantities in the symmetric phase. Numerical results regarding the corrections to the scaling laws, (i.e finite cut-off dependence) triviality, hyperscaling, universality and high-accuracy determinations of the critical exponents are discussed.Comment: LATTICE98(spin

High-Accuracy Calculations of the Critical Exponents of Dyson's Hierarchical Model

We calculate the critical exponent gamma of Dyson's hierarchical model by direct fits of the zero momentum two-point function, calculated with an Ising and a Landau-Ginzburg measure, and by linearization about the Koch-Wittwer fixed point. We find gamma= 1.299140730159 plus or minus 10^(-12). We extract three types of subleading corrections (in other words, a parametrization of the way the two-point function depends on the cutoff) from the fits and check the value of the first subleading exponent from the linearized procedure. We suggest that all the non-universal quantities entering the subleading corrections can be calculated systematically from the non-linear contributions about the fixed point and that this procedure would provide an alternative way to introduce the bare parameters in a field theory model.Comment: 15 pages, 9 figures, uses revte

Recent Changes in Irish Fertility. Quarterly Economic Commentary Special Article, May 1984

The main purpose of this paper is to provide a broad description of fertility trends in Ireland over the last two decades. The analysis investigates in particular whether there are regional (i.e., county) differences in relation to the levels of fertility and how these have changed. In the final part of the paper we discuss the likely future pattern of fertility trends and consider some economic and social implications arising therefrom. The last-mentioned aspect is now a matter of considerable significance since there are indications (from the annual births total) that the general decline in fertility has escalated to such an extent in recent years that the effects may be quite substantial and materialise within a relatively short period of time

Some Remarks on the Pade Unitarization of Low-Energy Amplitudes

We present a critical analysis of Pade-based methods for the unitarization of low energy amplitudes. We show that the use of certain Pade Approximants to describe the resonance region may lead to inaccurate determinations. In particular, we find that in the Linear Sigma Model the unitarization of the low energy amplitude through the inverse amplitude method produces essentially incorrect results for the mass and width of the sigma. Alternative sequences of Pades are studied and we find that the diagonal sequences (i.e., [N/N]) have much better convergence properties.Comment: 12 pages, 4 fig

Few-layer binder free graphene modified mercury film electrode for trace metal analysis by square wave anodic stripping voltammetry

A binding agent free graphene modified glassy carbon electrode in combination with an in situ plated mercury film electrode (Gr-GC-HgFE) was used as a highly sensitive electrochemical platform for the determination of Zn2+, Cd2+ and Pb2+ in 0.1 M acetate buffer (pH 4.6) by square-wave anodic stripping voltammetry (SWASV). Instrumental parameters such as deposition potential, deposition time and electrode rotation speed were optimized. The Gr-GC-HgFE sensing platform exhibited improved sensitivity for metal ion detection, in addition to well defined, reproducible and sharp stripping signals. Two linear calibration curves ranging from 0 –10 μg L−1 and 0 – 60 μg L−1 were identified yielding detection limits of 0.08 μg L−1, 0.05 μg L−1 and 0.14 μg L−1 for Zn2+, Cd2+ and Pb2+, respectively, for simultaneous analysis and 0.04 μg L−1, 0.11 μg L−1 and 0.14 μg L−1 for Zn2+, Cd2+ and Pb2+, respectively, for individual analysis when using a deposition time of 120 s. For practical applications recovery studies using tap water samples spiked with target metal ions gave recoveries within 10% of the spiked amount. Much better recoveries were obtained for the individual analysis in comparison with simultaneous analysis.Web of Scienc

Vector Meson Dominance as the first order of a sequence of Pade Approximants

The use of Pade Approximants for the analysis of the pion vector form-factor is discussed and justified in this talk. The method is tested first in a theoretical model and applied then on real experimental data. It is shown how the Pade Approximants provide a convenient and reliable framework to incorporate both low and high energy information in the euclidean region, leading to improved determinations of the low energy parameters such as, e.g., the quadratic radius ^pi_V.Comment: 4 pages, 3 figures, espcrc2 style. To appear in the proceedings of the 14th International QCD Conference, QCD 08, 7-12 July 2008, Montpellier (France

Contestable adulthood: variability and disparity in markers for negotiating the transition to adulthood

Recent research has identified a discreet set of subjective markers that are seen as characterizing the transition to adulthood. The current study challenges this coherence by examining the disparity and variability in young people’s selection of such criteria. Four sentence-completion cues corresponding to four differentcontexts in which adult status might be contested were given to 156 British 16- to 17-year-olds. Their qualitative responses were analyzed to explore patterns whilst capturing some of their richness and diversity. An astonishing amount of variability emerged, both within and between cued contexts.The implications of this variability for how the transition to adulthood is experienced are explored. The argument is made that markers of the transition to adulthood are not merely reflective of the bio–psycho–social development of young people. Rather, adulthood here is seen as an essentially contested concept,located within the discursive interactional environment in which young people participate