Non-Gaussianity in three fluid curvaton model

The generation of non-gaussianity is studied in a three fluid curvaton model. By utilizing second order perturbation theory we derive general formulae for the large scale temperature fluctuation and non-gaussianity parameter, $f_{NL}$, that includes the possibility of a non-adiabatic final state. In the adiabatic limit we recover previously known results. The results are applied to a three fluid curvaton model where the curvaton decays into radiation and matter. We find that the amount of non-gaussianity decreases as the final state of the system becomes more adiabatic and that the generated non-gaussianity in the scenario is small, $|f_{NL}| \sim \mathcal{O}(1)$.Comment: 10 pages, 2 figure

Constraints on the three-fluid model of curvaton decay

A three fluid system describing the decay of the curvaton is studied by numerical and analytical means. We place constraints on the allowed interaction strengths between the fluids and initial curvaton density by requiring that the curvaton decays before nucleosynthesis while nucleosynthesis, radiation-matter equality and decoupling occur at correct temperatures. We find that with a continuous, time-independent interaction, a small initial curvaton density is naturally preferred along with a low reheating temperature. Allowing for a time-dependent interaction, this constraint can be relaxed. In both cases, a purely adiabatic final state can be generated, but not without fine-tuning. Unlike in the two fluid system, the time-dependent interactions are found to have a small effect on the curvature perturbation itself due to the different nature of the system. The presence of non-gaussianity in the model is discussed.Comment: 9 pages, 10 figure

Tensile-strained GaAsN quantum dots on InP

Self-assembled quantum dots are typically fabricated from compressive-strained material systems, e.g., InAs on GaAs. In this letter, self-assembled quantum dots from tensile-strained GaAsN on InP are demonstrated. GaAsN on InP has type-I band alignment. Stranski-Krastanov growth mode is not observed, but in situannealing of the uncapped samples results in the formation of islands. Photoluminescence spectra from the buried GaAsN show separate peaks due to a wetting layer and islands around the energies of 1.3 and 1.1eV, respectively.Peer reviewe

Updated analysis of meson-nucleon sigma terms in the perturbative chiral quark model

We present an updated analysis of meson-baryon sigma terms in the perturbative chiral quark model, which is based on effective chiral Lagrangian. The new feature concerns the inclusion of excited states in the quark propagator. Its influence on meson loops is shown to lead in particular for the pion-nucleon sigma term to an enhancement relevant for the current evaluation of this quantity. We also determine various flavor combinations of the scalar nucleon form factors and their respective low-momentum transfer limits.Comment: 26 pages, 10 figures, to be published in Phys Rev

Ion exchange resin – Bipolar membrane electrodialysis hybrid process for reverse osmosis permeate remineralization: Cation exchange resins equilibria and kinetics

Reverse osmosis (RO) membrane technology is widely used for producing high-quality drinking water. Yet RO permeate is by itself acidic (pH = 5.5 to 6.0), unbuffered and has low mineral content, therefore post treatment i.e., remineralization is mostly required. An ion exchange resin – bipolar membrane electrodialysis hybrid process was developed for sustainable RO permeate remineralization. Fundamental phenomena in the recovery of calcium and magnesium by ion exchange to remineralize reverse osmosis permeate were investigated. Sorption equilibrium and mass transfer kinetics were investigated for weakly acidic (Amberlite IRC747, Amberlite IRC748, Lewatit S8227) and strongly acidic (DOWEX Marathon MSC) cation exchange resins. Most suitable resin for the remineralization process should have high selectivity for calcium and magnesium and low selectivity for monovalent ions to avoid adding undesired ions to the remineralised water downstream as well as relatively fast mass transfer kinetics. The isotherms were correlated with the stoichiometric ion exchange isotherm and the Langmuir-Freundlich (Sips) isotherm. All resins showed high selectivity for ions with higher valence, but weakly acidic cation exchange (WAC) resins showed significantly lower selectivity towards monovalent ions than the strongly acidic cation exchange resin. The influence of each resin functional group, charge density and degree of protonation was shown to have a major effect on the resin selectivity. Amberlite IRC748 had the lowest selectivity (KNH4+/Na+ = 0.77 0.19) and removal (46%) for ammonium in a single-component system. The mass transfer rate was found to be controlled by intraparticle diffusion rather than film diffusion. Amberlite IRC748 is recommended for use in a remineralization process where divalent ions are present because of its favourable sorption and higher mass transfer kinetics (Ks = 8.65 0.58 × 10−12, 7.95 0.38 × 10−12 m2/s for calcium and magnesium, respectively)

A hybrid process combining ion exchange resin and bipolar membrane electrodialysis for reverse osmosis remineralization

A new reverse osmosis (RO) permeate remineralization process combining ion exchange resin and bipolar membrane electrodialysis (BMED) was developed. Its feasibility for hardness ions recovery and RO permeate remineralization was investigated. The effect of several operation conditions on the efficiency of the combined remineralization process was studied. Highly efficient cation exchange resin loading was achieved at a low flow rate and low feed solution concentration. The recovered calcium purity and yield considerably improved under gradient elution methods in comparison with commonly applied conventional isocratic elution methods using the same eluent quantity. The purity of the produced acid and base using BMED dropped noticeably with increasing feed NaCl concentration, presumably related to decreased permselectivity of the ion-exchange membranes. The drop in the purity of the calcium recovered when eluting the cation exchange resin with BMED-produced HCl in comparison with commercially available acid at 50 % yield was shown not to affect the remineralization process, where a dilution factor could be applied. This study confirmed the technical feasibility of the developed process for RO permeate remineralization. However, its application can be limited by the water source characteristics, the energy-intensive bipolar membrane process, and applied operational conditions, where more investigation is still needed.</p

Using multiple imputation and intervention-based scenarios to project the mobility of older adults

Background: Projections of the development of mobility limitations of older adults are needed for evidence-based policy making. The aim of this study was to generate projections of mobility limitations among older people in the United States, England, and Finland. Methods: We applied multiple imputation modelling with bootstrapping to generate projections of stair climbing and walking limitations until 2026. A physical activity intervention producing a beneficial effect on self-reported activities of daily living measures was identified in a comprehensive literature search and incorporated in the scenarios used in the projections. We utilised the harmonised longitudinal survey data from the Ageing Trajectories of Health – Longitudinal Opportunities and Synergies (ATHLOS) project (N = 24,982). Results: Based on the scenarios from 2012 to 2026, the prevalence of walking limitations will decrease from 9.4 to 6.4%. A physical activity intervention would decrease the prevalence of stair climbing limitations compared with no intervention from 28.9 to 18.9% between 2012 and 2026. Conclusions: A physical activity intervention implemented on older population seems to have a positive effect on maintaining mobility in the future. Our method provides an interesting option for generating projections by incorporating intervention-based scenarios

Hyperglycemic conditions modulate connective tissue reorganization by human vascular smooth muscle cells through stimulation of hyaluronan synthesis.

Changes in the extracellular matrix organization within vascular walls are critical events in the process of atherosclerosis including diabetic macroangiopathy. Here, we examined whether glucose can directly modulate connective tissue reorganization by human vascular smooth muscle cells (VSMCs). Using a collagen gel contraction (CGC) assay, we demonstrated that in comparison with normal glucose concentration (5 mM), high glucose concentration (25 mM) inhibits the efficacy of VSMCs to contract collagen gels. With human genome microarrays, we showed a significant increase in the expression of hyaluronan synthase 2 (HAS2) by VSMCs in hyperglycemic conditions. The finding was verified with quantitative real-time polymerase chain reaction, which also revealed that the expression of the other hyaluronan synthesizing enzymes, HAS1 and HAS3, was stimulated concomitantly. A corresponding increase was observed in hyaluronan (HA) production. Treatment of VSMCs either with hyaluronidase or with 4-methylumbelliferone, an inhibitor of HA synthesis, partially restored the diminished CGC efficacy of VSMCs in hyperglycemic conditions. In conclusion, high glucose concentration stimulated HA synthesis by VSMCs and modulated their ability to reorganize collagen-rich matrix. Because HA is known to enhance the development of atherosclerosis and restenosis after percutaneous coronary interventions, our study provides a new potential mechanism whereby hyperglycemia leads to disturbed vascular remodeling in diabetic patients through stimulation of HA synthesis

Yield reduction caused by a soil-borne disease of naked, dwarf, and conventional oat in Finland

A severe disease occurred in the field plots of naked (cv. Salomon), dwarf (cv. Pal), and conventional oat (cvs. Jalostettu maatiainen and Salo) at the Viikki Experimental Farm of the University of Helsinki, Finland, in 1994 and 1995. Symptoms were expressed as grayish-brown necrotic areas on the lower leaves which killed plants from the seedling to heading stage, the effect being cultivar dependent. The proportion of plants killed contributed to the yield losses. The infection also resulted in less grains per panicle and lower weight of both panicle and vegetative above-ground biomass. From a total of 57 fungal isolates obtained from infected leaves, Fusarium culmorum (W.G.Sm.) Sacc. and F. sambucinum Fuck, dominated and subsequently caused infection (particularly foot and root rot) in oat in laboratory tests. These two Fusarium spp. were considered to be the primary causal agents of the symptoms observed in the field, although other pathogens may have been present. The disease was probably soil-borne. The results of this study suggested that the unusually dry and warm weather during late June and in July was the principal factor behind the severe disease outbreak