Meson-Baryon Form Factors in Chiral Colour Dielectric Model

The renormalised form factors for pseudoscalar meson-baryon coupling are computed in chiral colour dielectric model. This has been done by rearranging the Lippmann-Schwinger series for the meson baryon scattering matrix so that it can be expressed as a baryon pole term with renormalized form factors and baryon masses and the rest of the terms which arise from the crossed diagrams. Thus we are able to obtain an integral equation for the renormalized meson-baryon form factors in terms of the bare form factors as well as an expression for the meson self energy. This integral equation is solved and renormalized meson baryon form factors and renormalized baryon masses are computed. The parameters of the model are adjusted to obtain a best fit to the physical baryon masses. The calculations show that the renormalized form factors are energy-dependent and differ from the bare form factors primarily at momentum transfers smaller than 1 GeV. At nucleon mass, the change in the form factors is about 10% at zero momentum transfer. The computed form factors are soft with the equivalent monopole cut-off mass of about 500 MeV. The renormalized coupling constants are obtained by comparing the chiral colour dielectric model interaction Hamiltonian with the standard form of meson-nucleon interaction Hamiltonian. The ratio of $\Delta N\pi$ and $NN\pi$ coupling constants is found to be about 2.15. This value is very close to the experimental value.Comment: 16 pages, 7 postscript figure

Sharing Longevity Risk: Why Governments Should Issue Longevity Bonds

Government-issued longevity bonds would allow longevity risk to be shared efficiently and fairly between generations. In exchange for paying a longevity risk premium, the current generation of retirees can look to future generations to hedge their systematic longevity risk. Longevity bonds will lead to a more secure pension savings market, together with a more efficient annuity market. By issuing longevity bonds, governments can aid the establishment of reliable longevity indices and key price points on the longevity risk term structure and help the emerging capital market in longevity-linked instruments to build on this term structure with liquid longevity derivatives

Sex-specific mortality forecasting for UK countries: a coherent approach

This paper introduces a gender specific model for the joint mortality projection of three countries (England and Wales combined, Scotland, and Northern Ireland) of the United Kingdom. The model, called 2-tier Augmented Common Factor model, extends the classical Lee and Carter [26] and Li and Lee [32] models, with a common time factor for the whole UK population, a sex specific period factor for males and females, and a specific time factor for each country within each gender. As death counts in each subpopulation are modelled directly, a Poisson framework is used. Our results show that the 2-tier ACF model improves the in-sample fitting compared to the use of independent LC models for each subpopulation or of independent Li and Lee models for each couple of genders within each country. Mortality projections also show that the 2-tier ACF model produces coherent forecasts for the two genders within each country and different countries within each gender, thus avoiding the divergence issues arising when independent projections are used. The 2-tier ACF is further extended to include a cohort term to take into account the faster improvements of the UK ‘golden generation’

Intergenerational Communication – an interdisciplinary mapping review of research between 1996 and 2017

Concerns have been raised regarding the limited opportunities for intergenerational communication both outside and within the family. This “mapping review” draws together empirical literature in the topic published since 1996. Three hundred and twenty-four published studies met inclusion criteria, based on abstract review. The contents of each study were subjected to thematic analysis and nine broad themes emerged. These were (1) Dynamics of relationships, (2) Health & Well-being, (3) Learning & Literacy, (4) Attitudes, (5) Culture, (6) Digital, (7) Space, (8) Professional Development, and (9) Gender & Sexual Orientation. Studies commonly intersected disciplinary research areas. There was a marked rise across three key academic journals since 2007. An emergent finding was that a third of the studies relate to programs addressing intergenerational interventions, but many of these were primarily descriptive and failed to specify a primary outcome. Review implications and future research directions are discussed

Sensitivity of Localized Surface Plasmon Resonances to Bulk and Local Changes in the Optical Environment

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry C copyright © 2009 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/jp810322qSingle rod-shaped and disk-shaped gold nanoparticles with sizes ranging from 60 to 162 nm were analyzed using dark-field scattering spectroscopy. The sensitivity of the localized surface plasmon resonance (LSPR) of each nanoparticle to both a bulk and a local change in the refractive index of the environment was obtained by monitoring the change in the spectral position of the LSPR. It was found that the rods were more sensitive to changes in both the local environment and the bulk environment, in particular rods with a length > 110 nm. This behavior was confirmed by finite element modeling of the structures that clearly indicated a saturation of the relative wavelength shift for the disks as the diameter increased whereas the sensitivity of the rods continued to increase linearly with increasing length. This disparity in the behavior of the two types of nanoparticle may in part be attributed to two principal effects associated with the presence of the substrate: first, that the proportion of the surface area of the nanoparticle in contact with the substrate is larger for the disk than for the rod; second, that the LSPR electromagnetic field is more concentrated within the superstrate for the rod compared to the disk. Further analysis of data obtained from modeling a changing local environment indicates that, although the rods are more sensitive, both rods and disks exhibit a similar field confinement

Microbial−mammalian cometabolites dominate the age-associated urinary metabolic phenotype in Taiwanese and American populations

Understanding the metabolic processes associated with aging is key to developing effective management and treatment strategies for age-related diseases. We investigated the metabolic profiles associated with age in a Taiwanese and an American population. 1H NMR spectral profiles were generated for urine specimens collected from the Taiwanese Social Environment and Biomarkers of Aging Study (SEBAS; n = 857; age 54–91 years) and the Mid-Life in the USA study (MIDUS II; n = 1148; age 35–86 years). Multivariate and univariate linear projection methods revealed some common age-related characteristics in urinary metabolite profiles in the American and Taiwanese populations, as well as some distinctive features. In both cases, two metabolites—4-cresyl sulfate (4CS) and phenylacetylglutamine (PAG)—were positively associated with age. In addition, creatine and β-hydroxy-β-methylbutyrate (HMB) were negatively correlated with age in both populations (p < 4 × 10–6). These age-associated gradients in creatine and HMB reflect decreasing muscle mass with age. The systematic increase in PAG and 4CS was confirmed using ultraperformance liquid chromatography–mass spectrometry (UPLC–MS). Both are products of concerted microbial–mammalian host cometabolism and indicate an age-related association with the balance of host–microbiome metabolism

Controlling interferometric properties of nanoporous anodic aluminium oxide

A study of reflective interference spectroscopy [RIfS] properties of nanoporous anodic aluminium oxide [AAO] with the aim to develop a reliable substrate for label-free optical biosensing is presented. The influence of structural parameters of AAO including pore diameters, inter-pore distance, pore length, and surface modification by deposition of Au, Ag, Cr, Pt, Ni, and TiO2 on the RIfS signal (Fabry-Perot fringe) was explored. AAO with controlled pore dimensions was prepared by electrochemical anodization of aluminium using 0.3 M oxalic acid at different voltages (30 to 70 V) and anodization times (10 to 60 min). Results show the strong influence of pore structures and surface modifications on the interference signal and indicate the importance of optimisation of AAO pore structures for RIfS sensing. The pore length/pore diameter aspect ratio of AAO was identified as a suitable parameter to tune interferometric properties of AAO. Finally, the application of AAO with optimised pore structures for sensing of a surface binding reaction of alkanethiols (mercaptoundecanoic acid) on gold surface is demonstrated

Rhodium nanoparticles for ultraviolet plasmonics

The nonoxidizing catalytic noble metal rhodium is introduced for ultraviolet plasmonics. Planar tripods of 8 nm Rh nanoparticles, synthesized by a modified polyol reduction method, have a calculated local surface plasmon resonance near 330 nm. By attaching p-aminothiophenol, local field-enhanced Raman spectra and accelerated photodamage were observed under near-resonant ultraviolet illumination, while charge transfer simultaneously increased fluorescence for up to 13 min. The combined local field enhancement and charge transfer demonstrate essential steps toward plasmonically enhanced ultraviolet photocatalysis.This work has been supported by NSF-ECCS-12-32239. This work was partially supported by the Army’s In-house Laboratory Innovative Research program. Financial support from USAITCA (project no. W911NF-13-1-0245) and MICINN (Spanish Ministry of Science and Innovation, project no. FIS2013- 45854-P) is also acknowledged