447 research outputs found

    Reconsidering prenatal screening: an empirical-ethical approach to understand moral dilemmas as a question of personal preferences

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    In contrast to most Western countries, routine offer of prenatal screening is considered problematic in the Netherlands. The main argument against offering it to every pregnant woman is that women would be brought into a moral dilemma when deciding whether to use screening or not. This paper explores whether the active offer of a prenatal screening test indeed confronts women with a moral dilemma. A qualitative study was developed, based on a randomised controlled trial that aimed to assess the decision-making process of women when confronted with a test offer. A sample of 59 women was interviewed about the different factors balanced in decision-making. Participants felt themselves caught between a need for knowledge and their unwillingness to take on responsibility. Conflict was reported between wishes, preferences and ethical views regarding parenthood; however, women did not seem to be caught in a choice between two or more ethical principles. Participants balanced the interests of the family against that of the fetus in line with their values and their personal circumstances. Therefore, we conclude that they are not so much faced with an ethical dilemma as conflicting interests. We propose that caregivers should provide the opportunity for the woman to discuss her wishes and doubts to facilitate her decision. This approach would help women to assess the meaning of testing within their parental duties towards their unborn child and their current offsprin

    Criticality in confined ionic fluids

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    A theory of a confined two dimensional electrolyte is presented. The positive and negative ions, interacting by a 1/r1/r potential, are constrained to move on an interface separating two solvents with dielectric constants ϵ1\epsilon_1 and ϵ2\epsilon_2. It is shown that the Debye-H\"uckel type of theory predicts that the this 2d Coulomb fluid should undergo a phase separation into a coexisting liquid (high density) and gas (low density) phases. We argue, however, that the formation of polymer-like chains of alternating positive and negative ions can prevent this phase transition from taking place.Comment: RevTex, no figures, in press Phys. Rev.

    The global diffusion of inequality since 1970

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    Since 1970 income inequality has been stable or rising in almost every country in the world. It has not, however, risen at the same time or at the same rate throughout the world. This suggests the globalization, skills premium, and technological change explanations that prevail in the economics literature are likely incorrect, since all of these processes should in principle have relatively uniform global impacts. Instead, the timing and geo-cultural patterns of rising inequality bear the hallmarks of a diffusion model. Inequality has not arisen simultaneously around the world; it has "spread" from country to country in recognizable and sensible patterns. The diffusion model offers a simple, intuitively-appealing alternative to extraordinarily complex regression models of rising inequality. Diffusion can occur either through emulation (a macrophenomenological mechanism) or through coercion (a macrorealist mechanism). These two mechanisms are not mutually exclusive. Either or both can be used by national elites to effect major changes of policy regime. Diffusion by emulation and diffusion by coercion are two macro-level mechanisms that can be used as a template for understanding the implementation of inequality-increasing social and economic policies in diverse countries around the world. They can be differentiated through examination of the micro-level mechanisms through which diffusion occurred in specific historical cases. This injection of agency into the inequality debates requires extensive microlevel work on individual countries, but the clear existence of macro-level trends suggests that this micro-level work should be done within the context of some form of macro-level diffusion model.Collective Behavior & Social Movements section of the American Sociological Association, the Development Sociology section of the American Sociological Association, the Human Rights section of the American Sociological Association, the RC02 (Economy and Society) of the International Sociological Association and the School of Social & Political Sciences of the University of Sydney

    Blue laser cooling transitions in Tm I

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    We have studied possible candidates for laser cooling transitions in 169^{169}Tm in the spectral region 410 -- 420 nm. By means of saturation absorption spectroscopy we have measured the hyperfine structure and rates of two nearly closed cycling transitions from the ground state 4f136s2(2F0)(Jg=7/2)4\textrm{f}^{13}6\textrm{s}^2(^2\textrm{F}_0)(J_g=7/2) to upper states 4f12(3H5)5d3/26s2(Je=9/2)4\textrm{f}^{12}(^3\textrm{H}_5)5\textrm{d}_{3/2}6\textrm{s}^2(J_e=9/2) at 410.6 nm and 4f12(3F4)5d5/26s2(Je=9/2)4\textrm{f}^{12}(^3\textrm{F}_4)5\textrm{d}_{5/2}6\textrm{s}^2(J_e=9/2) at 420.4 nm and evaluated the life times of the excited levels as 15.9(8) ns and 48(6) ns respectively. Decay rates from these levels to neighboring opposite-parity levels are evaluated by means of Hartree-Fock calculations. We conclude, that the strong transition at 410.6 nm has an optical leak rate of less then 21052\cdot10^{-5} and can be used for efficient laser cooling of 169^{169}Tm from a thermal atomic beam. The hyperfine structure of two other even-parity levels which can be excited from the ground state at 409.5 nm and 418.9 nm is also measured by the same technique. In addition we give a calculated value of 7(2)7(2) s1^{-1} for the rate of magnetic-dipole transition at 1.14 μ\mum between the fine structure levels (Jg=7/2)(Jg=5/2)(J_g=7/2)\leftrightarrow(J'_g=5/2) of the ground state which can be considered as a candidate for applications in atomic clocks.Comment: 8 pages, 5 figure

    Clustering transitions in vibro-fluidized magnetized granular materials

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    We study the effects of long range interactions on the phases observed in cohesive granular materials. At high vibration amplitudes, a gas of magnetized particles is observed with velocity distributions similar to non-magnetized particles. Below a transition temperature compact clusters are observed to form and coexist with single particles. The cluster growth rate is consistent with a classical nucleation process. However, the temperature of the particles in the clusters is significantly lower than the surrounding gas, indicating a breakdown of equipartition. If the system is quenched to low temperatures, a meta-stable network of connected chains self-assemble due to the anisotropic nature of magnetic interactions between particles.Comment: 4 pages, 5 figure

    A molecular dynamics study on the equilibrium magnetization properties and structure of ferrofluids

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    We investigate in detail the initial susceptibility, magnetization curves, and microstructure of ferrofluids in various concentration and particle dipole moment ranges by means of molecular dynamics simulations. We use the Ewald summation for the long-range dipolar interactions, take explicitly into account the translational and rotational degrees of freedom, coupled to a Langevin thermostat. When the dipolar interaction energy is comparable with the thermal energy, the simulation results on the magnetization properties agree with the theoretical predictions very well. For stronger dipolar couplings, however, we find systematic deviations from the theoretical curves. We analyze in detail the observed microstructure of the fluids under different conditions. The formation of clusters is found to enhance the magnetization at weak fields and thus leads to a larger initial susceptibility. The influence of the particle aggregation is isolated by studying ferro-solids, which consist of magnetic dipoles frozen in at random locations but which are free to rotate. Due to the artificial suppression of clusters in ferro-solids the observed susceptibility is considerably lowered when compared to ferrofluids.Comment: 33 pages including 12 figures, requires RevTex

    Orientational order in dipolar fluids consisting of nonspherical hard particles

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    We investigate fluids of dipolar hard particles by a certain variant of density-functional theory. The proper treatment of the long range of the dipolar interactions yields a contribution to the free energy which favors ferromagnetic order. This corrects previous theoretical analyses. We determine phase diagrams for dipolar ellipsoids and spherocylinders as a function of the aspect ratio of the particles and their dipole moment. In the nonpolar limit the results for the phase boundary between the isotropic and nematic phase agree well with simulation data. Adding a longitudinal dipole moment favors the nematic phase. For oblate or slightly elongated particles we find a ferromagnetic liquid phase, which has also been detected in computer simulations of fluids consisting of spherical dipolar particles. The detailed structure of the phase diagram and its evolution upon changing the aspect ratio are discussed in detail.Comment: 35 pages LaTeX with epsf style, 11 figures in eps format, submitted to Phys. Rev.

    Water Management Solution of Reservoir Storage Function Under Condition of Measurement Uncertainties in Hydrological Input Data

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    AbstractThe paper describes a possible procedure of the rate uncertainty implementation to the continuous water stage measurement and uncertainties of state - discharge rating curve point positions, which the stage -discharge rating curves were fitted into the uncertainties of the real discharge series members. Then the members of discharge series under uncertainty impact were tested on the calculated values of the reservoir storage volume. The next step was the implementation of the uncertainties of the real discharge series members on the generation of the artificial discharge series of mean monthly discharge using the AR and ARMA generators and the determination of their impact on the calculated values of the reservoir storage volume

    A combined linkage and exome sequencing analysis for electrocardiogram parameters in the Erasmus Rucphen family study

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    Electrocardiogram (ECG) measurements play a key role in the diagnosis and prediction of cardiac arrhythmias and sudden cardiac death. ECG parameters, such as the PR, QRS, and QT intervals, are known to be heritable and genome-wide association studies of these phenotypes have been successful in identifying common variants; however, a large proportion of the genetic variability of these traits remains to be elucidated. The aim of this study was to discover loci potentially harboring rare variants utilizing variance component linkage analysis in 1547 individuals from a large family-based study, the Erasmus Rucphen Family Study (ERF). Linked regions were further explored using exome sequencing. Five suggestive linkage peaks were identified: two for QT interval (1q24, LOD = 2.63; 2q34, LOD = 2.05), one for QRS interval (1p35, LOD = 2.52) and two for PR interval (9p22, LOD = 2.20; 14q11, LOD = 2.29). Fine-mapping using exome sequence data identified a C > G missense variant (c.713C > G, p.Ser238Cys) in the FCRL2 gene associated with QT (rs74608430; P = 2.8 × 10-4, minor allele frequency = 0.019). Heritability analysis demonstrated that the SNP explained 2.42% of the trait's genetic variability in ERF (P = 0.02). Pathway analysis suggested that the gene is involved in cytosolic Ca2+ levels (P = 3.3 × 10-3) and AMPK stimulated fatty acid oxidat
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