Depolarization volume and correlation length in the homogenization of anisotropic dielectric composites

In conventional approaches to the homogenization of random particulate composites, both the distribution and size of the component phase particles are often inadequately taken into account. Commonly, the spatial distributions are characterized by volume fraction alone, while the electromagnetic response of each component particle is represented as a vanishingly small depolarization volume. The strong-permittivity-fluctuation theory (SPFT) provides an alternative approach to homogenization wherein a comprehensive description of distributional statistics of the component phases is accommodated. The bilocally-approximated SPFT is presented here for the anisotropic homogenized composite which arises from component phases comprising ellipsoidal particles. The distribution of the component phases is characterized by a two-point correlation function and its associated correlation length. Each component phase particle is represented as an ellipsoidal depolarization region of nonzero volume. The effects of depolarization volume and correlation length are investigated through considering representative numerical examples. It is demonstrated that both the spatial extent of the component phase particles and their spatial distributions are important factors in estimating coherent scattering losses of the macroscopic field.Comment: Typographical error in eqn. 16 in WRM version is corrected in arxiv versio

The Arbitration Profession in Transition: Final Report to the National Academy of Arbitrators

[Excerpt] In recent years there has been a dramatic increase in the arbitration and mediation of employment disputes outside the collective bargaining context. This increase has been part of a larger shift from reliance on litigation and enforcement agency resolution of disputes to the use of alternative dispute resolution (ADR), a trend particularly evident in the employment field. Over the course of several decades employees have gained a long list of rights and protections included in a variety of laws, ranging from anti-discrimination statutes to pension safeguards to statutory attempts to guarantee safer and healthier workplaces. The growing use of arbitration, mediation, and related techniques to resolve statutory claims arising in employment relations is in part the consequence of the high costs and long delays associated with the use of administrative agencies and the court system to resolve disputes. The unpredictability of jury awards has also prompted employers and employees to opt for ADR. The growing use of ADR in employment disputes has occurred both inside and outside collective bargaining. In some union workplaces, the parties attempt to resolve statutory claims using the grievance and arbitration procedures in the collective bargaining agreement. In others, many, if not most, statutory claims are handled outside the collective bargaining arena, with employees pursuing their claims through the normal channels of agency and judicial resolution. In a minority but growing number of union-management relationships, the parties have created procedures for resolving statutory claims that are separate or “sheltered” from the collective bargaining agreement (Dunlop and Zack, 1997, particularly pp. 53–72; see also Zack, 1999, pp. 67–94). The growing use of arbitration and mediation to resolve employment disputes has been especially noteworthy in the nonunion sector. In the United States, as most people know, the proportion of the workforce that is unionized has been steadily declining for over forty years and currently stands at about 14 percent. Although the membership in the Canadian labor movement has not suffered as steep a decline, a similar trend is apparent there. As in organized workplaces, the growth of employment ADR in the nonunion sector is one consequence of employers’ attempts to avoid the high costs and long delays of the judicial and administrative routes. Of course, some nonunion employers are also motivated by a desire to provide their employees with fair and equitable dispute resolution procedures (Bingham and Chachere, 1999, pp. 95–135)

The Arbitration Profession in Transition: Preliminary Results From a Survey of the National Academy of Arbitrators

[Excerpt} In recent years, there has been a dramatic increase in the arbitration and mediation of employment-related disputes. This increase has been part of a larger shift from reliance on litigation and agency resolution of disputes to the use of alternative dispute resolution (ADR), a trend particularly evident in the employment field. Over the course of several decades employees have been granted a long list of rights and protections included in a variety of laws, ranging from antidiscrimination statutes to pension safeguards to statutory attempts to guarantee safer and healthier workplaces. The growing use of arbitration, mediation, and related techniques to resolve statutory claims arising in employment relations is largely the consequence of the high costs and long delays associated with the use of administrative agencies and the court system to resolve disputes arising under these various statutes. The growing use of ADR in employment disputes has occurred both inside and outside collective bargaining. In some union workplaces, the parties attempt to resolve statutory claims using the grievance and arbitration procedures in their collective bargaining agreements. In other union workplaces, many, if not most, statutory claims are handled outside the collective bargaining arena. Employees in many such organizations pursue their statutory claims through the normal channels of agency and judicial resolution. In a minority but growing number of union-management relationships, the parties have created procedures for resolving statutory claims that are separate or sheltered from the collective bargaining agreement. The growing use of arbitration and mediation to resolve employment disputes has been especially noteworthy in the nonunion sector. In the United States, as most people know, the proportion of the work force that is unionized has been steadily declining for over 40 years and currently stands at about 14 percent. Although the Canadian labor movement has not suffered as steep a decline as in the United States, a similar trend is apparent there. The growth of employment ADR in the nonunion sector is largely the consequence of employer attempts to avoid the high costs and long delays associated with the use of judicial and administrative means to resolve disputes. Of course, some nonunion employers are also motivated by a desire to provide their employees with fair and equitable dispute resolution procedures

Properties of simulated Milky Way-mass galaxies in loose group and field environments

We test the validity of comparing simulated field disk galaxies with the empirical properties of systems situated within environments more comparable to loose groups, including the Milky Way's Local Group. Cosmological simulations of Milky Way-mass galaxies have been realised in two different environment samples: in the field and in environments with similar properties to the Local Group. Apart from the environments of the galaxies, the samples are kept as homogeneous as possible with equivalent ranges in last major merger time, halo mass and halo spin. Comparison of these two samples allow for systematic differences in the simulations to be identified. Metallicity gradients, disk scale lengths, colours, magnitudes and age-velocity dispersion relations are studied for each galaxy in the suite and the strength of the link between these and environment of the galaxies is studied. The bulge-to-disk ratio of the galaxies show that these galaxies are less spheroid dominated than many other simulated galaxies in literature with the majority of both samples being disk dominated. We find that secular evolution and mergers dominate the spread of morphologies and metallicity gradients with no visible differences between the two environment samples. In contrast with this consistency in the two samples there is tentative evidence for a systematic difference in the velocity dispersion-age relations of galaxies in the different environments. Loose group galaxies appear to have more discrete steps in their velocity dispersion-age relations. We conclude that at the current resolution of cosmological galaxy simulations field environment galaxies are sufficiently similar to those in loose groups to be acceptable proxies for comparison with the Milky Way provided that a similar assembly history is considered.Comment: 16 pages, 11 figures, abstract abridged for arXiv. Accepted for publication in Astronomy & Astrophysic

Ab-initio No-Core Gamow Shell Model calculations with realistic interactions

No-Core Gamow Shell Model (NCGSM) is applied for the first time to study selected well-bound and unbound states of helium isotopes. This model is formulated on the complex energy plane and, by using a complete Berggren ensemble, treats bound, resonant, and scattering states on equal footing. We use the Density Matrix Renormalization Group method to solve the many-body Schr\"{o}dinger equation. To test the validity of our approach, we benchmarked the NCGSM results against Faddeev and Faddeev-Yakubovsky exact calculations for $^3$H and $^4$He nuclei. We also performed {\textit ab initio} NCGSM calculations for the unstable nucleus $^5$He and determined the ground state energy and decay width, starting from a realistic N$^3$LO chiral interaction.Comment: 17 pages, 14 figures. Revised version. Discussion on microscopic overlap functions, SFs and ANCs is added. Added references. Accepted for publication at PR

Depolarization regions of nonzero volume in bianisotropic homogenized composites

In conventional approaches to the homogenization of random particulate composites, the component phase particles are often treated mathematically as vanishingly small, point-like entities. The electromagnetic responses of these component phase particles are provided by depolarization dyadics which derive from the singularity of the corresponding dyadic Green functions. Through neglecting the spatial extent of the depolarization region, important information may be lost, particularly relating to coherent scattering losses. We present an extension to the strong-property-fluctuation theory in which depolarization regions of nonzero volume and ellipsoidal geometry are accommodated. Therein, both the size and spatial distribution of the component phase particles are taken into account. The analysis is developed within the most general linear setting of bianisotropic homogenized composite mediums (HCMs). Numerical studies of the constitutive parameters are presented for representative examples of HCM; both Lorentz-reciprocal and Lorentz-nonreciprocal HCMs are considered. These studies reveal that estimates of the HCM constitutive parameters in relation to volume fraction, particle eccentricity, particle orientation and correlation length are all significantly influenced by the size of the component phase particles

Ohm's Law for a Relativistic Pair Plasma

We derive the fully relativistic Ohm's law for an electron-positron plasma. The absence of non-resistive terms in Ohm's law and the natural substitution of the 4-velocity for the velocity flux in the relativistic bulk plasma equations do not require the field gradient length scale to be much larger than the lepton inertial lengths, or the existence of a frame in which the distribution functions are isotropic.Comment: 12 pages, plain TeX, Phys. Rev. Lett. 71 3481 (1993

Probing neutrino masses with CMB lensing extraction

We evaluate the ability of future cosmic microwave background (CMB) experiments to measure the power spectrum of large scale structure using quadratic estimators of the weak lensing deflection field. We calculate the sensitivity of upcoming CMB experiments such as BICEP, QUaD, BRAIN, ClOVER and PLANCK to the non-zero total neutrino mass M_nu indicated by current neutrino oscillation data. We find that these experiments greatly benefit from lensing extraction techniques, improving their one-sigma sensitivity to M_nu by a factor of order four. The combination of data from PLANCK and the SAMPAN mini-satellite project would lead to sigma(M_nu) = 0.1 eV, while a value as small as sigma(M_nu) = 0.035 eV is within the reach of a space mission based on bolometers with a passively cooled 3-4 m aperture telescope, representative of the most ambitious projects currently under investigation. We show that our results are robust not only considering possible difficulties in subtracting astrophysical foregrounds from the primary CMB signal but also when the minimal cosmological model (Lambda Mixed Dark Matter) is generalized in order to include a possible scalar tilt running, a constant equation of state parameter for the dark energy and/or extra relativistic degrees of freedom.Comment: 13 pages, 4 figures. One new figure and references added. Version accepted for publicatio