756 research outputs found

    Two Different Mismatches: Integrating the Developmental and the Evolutionary-Mismatch Hypothesis

    Get PDF
    Evolutionary psychology aims to understand the origins of the human mind, including disease. Several theories about the origins of disease have been proposed. One concerns a developmental mismatch—a mismatch might occur at the individual level between the environment experienced during childhood and the environment the adult finds herself in, possibly resulting in disease. A second theory concerns the idea of an evolutionary mismatch—humans are adapted to ancestral conditions so they might now experience a mismatch with their modern environment, possibly resulting in disease. A third theory—differential susceptibility—outlines how genetic and epigenetic differences influence the extent to which humans are susceptible to rearing, including positive and negative experiences. Because of these differences, some individuals are more prone to develop disease than others. We review empirical studies that substantiate these theories and argue that an overarching theory that integrates these three lines into one provides a more accurate understanding of disease from an evolutionary perspective

    An explorative philosophical study of envisaging the electrical energy infrastructure of the future

    Get PDF
    The electrical energy infrastructure is one of the key life-sustaining technologies of contemporary Western society. This infrastructure is extremely complex due to its size, its multifarious technologies, and its interweaving with societal structures. Smart grids are important in future infrastructure, yet extant literature does not adequately address this complexity. This paper argues that different elements of the philosophy of Dooyeweerd offer a key to understanding this intricate complexity more fundamentally. Key concepts are the ideas of normative practices, enkapsis (intertwinement) of practices, individuality structures, and ideals and basic beliefs. By developing these ideas in the context of smart grid engineering, our research contributes to philosophy of technology, philosophy of design, and philosophy of sustainability. It offers an ontological analysis of these infrastructures, pointing a direction to the development of workable infrastructures and supporting the transition to a sustainable society

    The effect of population variation on the accuracy of sex estimates derived from basal occipital discriminant functions

    No full text
    Multiple discriminant functions that estimate sex from the dimensions of the basal occipital have been published. However, as there is limited exploration of basal dimension variation between groups, the accuracy of these functions when applied to archaeological material is unknown. This study compares basal dimensions between four known sex-at-death post-medieval European samples and explores how metric differences impact on the accuracy of sex assessment discriminant functions. Published data from St Bride’s, London (n = 146) and the Georges Olivier collection, Paris (n = 68) were compared with new data from the eighteenth to nineteenth century Dutch Middenbeemster sample (n = 74) and the early twentieth century Rainer sample, Romania (n = 282) using independent t tests. The Middenbeemster and Rainer data were substituted into six published discriminant functions derived from the St Bride’s and the Georges Olivier samples, and the results were compared to their known sex. Multiple statistically significant differences were found between the four groups. Of the six discriminant functions tested, five failed to reach the published accuracy and fell below chance. In addition, even where the samples were statistically comparable in means, trends for difference also impacted the accuracy of discriminant functions. Enough variation in basal occipital dimensions existed in the European groups to decrease the accuracy of sex estimation discriminant functions to unusable. Possible inter-observer error, varying genetic, socioeconomic, and geographical factors are likely causes of dimension variation. This research further highlights the dangers of using sex estimation discriminant functions on samples that differ to the original derivative population and demonstrates the need for more rigorous testing

    Surface and bulk transitions in three-dimensional O(n) models

    Get PDF
    Using Monte Carlo methods and finite-size scaling, we investigate surface criticality in the O(n)(n) models on the simple-cubic lattice with n=1n=1, 2, and 3, i.e. the Ising, XY, and Heisenberg models. For the critical couplings we find Kc(n=2)=0.4541655(10)K_{\rm c}(n=2)=0.454 1655 (10) and Kc(n=3)=0.693002(2)K_{\rm c}(n=3)= 0.693 002 (2). We simulate the three models with open surfaces and determine the surface magnetic exponents at the ordinary transition to be yh1(o)=0.7374(15)y_{h1}^{\rm (o)}=0.7374 (15), 0.781(2)0.781 (2), and 0.813(2)0.813 (2) for n=1n=1, 2, and 3, respectively. Then we vary the surface coupling K1K_1 and locate the so-called special transition at Îșc(n=1)=0.50214(8)\kappa_{\rm c} (n=1)=0.50214 (8) and Îșc(n=2)=0.6222(3)\kappa_{\rm c} (n=2)=0.6222 (3), where Îș=K1/K−1\kappa=K_1/K-1. The corresponding surface thermal and magnetic exponents are yt1(s)=0.715(1)y_{t1}^{\rm (s)} =0.715 (1) and yh1(s)=1.636(1)y_{h1}^{\rm (s)} =1.636 (1) for the Ising model, and yt1(s)=0.608(4)y_{t1}^{\rm (s)} =0.608 (4) andyh1(s)=1.675(1)y_{h1}^{\rm (s)} =1.675 (1) for the XY model. Finite-size corrections with an exponent close to -1/2 occur for both models. Also for the Heisenberg model we find substantial evidence for the existence of a special surface transition.Comment: TeX paper and 10 eps figure

    Monte Carlo Renormalization of the 3-D Ising model: Analyticity and Convergence

    Full text link
    We review the assumptions on which the Monte Carlo renormalization technique is based, in particular the analyticity of the block spin transformations. On this basis, we select an optimized Kadanoff blocking rule in combination with the simulation of a d=3 Ising model with reduced corrections to scaling. This is achieved by including interactions with second and third neighbors. As a consequence of the improved analyticity properties, this Monte Carlo renormalization method yields a fast convergence and a high accuracy. The results for the critical exponents are y_H=2.481(1) and y_T=1.585(3).Comment: RevTeX, 4 PostScript file

    Pion Mass Effects in the Large NN Limit of \chiPT

    Get PDF
    We compute the large NN effective action of the O(N+1)/O(N)O(N+1)/O(N) non-linear sigma model including the effect of the pion mass to order mπ2/fπ2m^2_{\pi}/f_{\pi}^2. This action is more complex than the one corresponding to the chiral limit not only because of the pion propagators but also because chiral symmetry produce new interactions proportional to mπ2/fπ2m^2_{\pi}/f_{\pi}^2. We renormalize the action by including the appropriate counter terms and find the renormalization group equations for the corresponding couplings. Then we estudy the unitarity propierties of the scattering amplitudes. Finally our results are applied to the particular case of the linear sigma model and also are used to fit the pion scattering phase shifts.Comment: FT/UCM/18/9

    A global fit of ππ\pi\pi and πK\pi K elastic scattering in ChPT with dispersion relations

    Get PDF
    We apply the one-loop results of the SU(3)L×SU(3)RSU(3)_L\times SU(3)_R ChPT suplemented with the inverse amplitude method to fit the available experimental data on ππ\pi\pi and πK\pi K scattering. With esentially only three parameters we describe accurately data corresponding to six different channels, namely (I,J)=(0,0),(2,0),(1,1),(1/2,0),(3/2,0)(I,J)=(0,0), (2,0), (1,1), (1/2,0), (3/2,0) and (1/2,1)(1/2,1). In addition we reproduce the first resonances of the (1,1)(1,1) and (1/2,1)(1/2,1) channel with the right mass corresponding to the ρ\rho and the K∗(892)K^*(892) particles.Comment: 19 pages, 5 figures available on request, FT/UCM/10/9

    S-wave Meson-Meson Scattering from Unitarized U(3) Chiral Lagrangians

    Get PDF
    An investigation of the s-wave channels in meson-meson scattering is performed within a U(3) chiral unitary approach. Our calculations are based on a chiral effective Lagrangian which includes the eta' as an explicit degree of freedom and incorporates important features of the underlying QCD Lagrangian such as the axial U(1) anomaly. We employ a coupled channel Bethe-Salpeter equation to generate poles from composed states of two pseudoscalar mesons. Our results are compared with experimental phase shifts up to 1.5 GeV and effects of the eta' within this scheme are discussed.Comment: 18 pages, 6 figure

    I=2 ππ\pi\pi Scattering Phase Shift with two Flavors of O(a)O(a) Improved Dynamical Quarks

    Get PDF
    We present a lattice QCD calculation of phase shift including the chiral and continuum extrapolations in two-flavor QCD. The calculation is carried out for I=2 S-wave ππ\pi\pi scattering. The phase shift is evaluated for two momentum systems, the center of mass and laboratory systems, by using the finite volume method proposed by L\"uscher in the center of mass system and its extension to general systems by Rummukainen and Gottlieb. The measurements are made at three different bare couplings ÎČ=1.80\beta = 1.80, 1.95 and 2.10 using a renormalization group improved gauge and a tadpole improved clover fermion action, and employing a set of configurations generated for hadron spectroscopy in our previous work. The illustrative values we obtain for the phase shift in the continuum limit are ÎŽ\delta(deg.) =−3.50(64)= - 3.50(64), −9.5(30) - 9.5(30) and −16.9(64) - 16.9(64) for s(GeV)\sqrt{s}({\rm GeV}) =0.4=0.4, 0.6 0.6 and 0.8 0.8, which are consistent with experiment.Comment: 40 page
    • 

    corecore