Population imbalanced fermions in harmonically trapped optical lattices

The attractive Fermi-Hubbard Hamiltonian is solved via the Bogoliubov-de Gennes formalism to analyze the ground state phases of population imbalanced fermion mixtures in harmonically trapped two-dimensional optical lattices. In the low density limit the superfluid order parameter modulates in the radial direction towards the trap edges to accommodate the unpaired fermions that are pushed away from the trap center with a single peak in their density. However in the high density limit while the order parameter modulates in the radial direction towards the trap center for low imbalance, it also modulates towards the trap edges with increasing imbalance until the superfluid to normal phase transition occurs beyond a critical imbalance. This leads to a single peak in the density of unpaired fermions for low and high imbalance but leads to double peaks for intermediate imbalance.Comment: 4 pages with 4 figures, accepted to appear in PR

Tackling disinvestment in health care services

Rising levels of demand due to ageing populations and increases in long term conditions (White 2007), increased levels of expectation amongst patients and inflationary pressure caused by the rising cost of new technologies are amongst the explanations for the funding shortfalls in government funded health systems across the world (Newhouse 1992). The challenge facing these health systems has also been intensified by the worldwide economic downturn. Within health systems, efforts have been made to increase productivity and efficiency and to control costs without reducing quality (Garner and Littlejohns 2011) but the scale of the task necessitates further action (Donaldson et al. 2010). Beyond productivity and efficiency gains the next logical step for decision makers is disinvestment in cost-ineffective services, prioritisation of funding for one service over another or what Prasad (2012) refers to as ‘medical reversal’. The aims of this study were to explore the experiences of budget holders within the English National Health Service (NHS) in their attempts to implement programmes of disinvestment, and to consider factors which influence the success (or otherwise) of this activity. This paper begins with clarification of terminology and a summary of the current state of knowledge with regard to health service disinvestment, before presenting and discussing findings. The research suggests that disinvestment activity is varied across organisations and ranges from ‘invest to save’ schemes through to ‘true disinvestment.’ Although the majority of interviewees accept that disinvestment is necessary most had made little progress at the time of interview beyond ‘picking the low hanging fruit’. Interviewees identify a number of determinants of disinvestment such as: local/national relationships, co-ordination/ collaboration and; professional understanding and support

Ion Exchange-Precipitation for Nutrient Recovery from Dilute Wastewater

Regulated phosphorus (P) and nitrogen (N) discharges and the cost of fertilizer provide economic drivers for nutrient removal and recovery from wastewater. This study used ion exchange (IX) in dilute (domestic) wastewater to concentrate nutrients with subsequent recovery by struvite precipitation. This is the first tertiary wastewater treatment study directly comparing P removal using a range of Fe, Cu, and Al-based media followed by clinoptilolite IX columns for N removal and precipitation using the combined regenerants. Phosphate removal prior to breakthrough was 0.5–2.0 g P Lmedia−1, providing effluent concentrations −1 PO4-P and −1 NH4-N for ≥80 bed volumes. Dow-FeCu resin provided effective P removal, efficient neutral pH regeneration and 560 mg P L−1 in the regeneration eluate (≥100× concentration factor). Exchange capacity of clinoptilolite in column mode was 3.9–6.1 g N Lmedia−1 prior to breakthrough. Precipitation using the combined cation and anion regenerants resulted in a maximum of 74% P removal using Dow-FeCu. Precipitates contained impurities, including Al3+, Ca2+, and Fe. Overall, the IX-precipitation recovery process removed ≥98% P and 95% N and precipitates contained 13% P and 1.6% N. This sequential process can satisfy increasingly stringent wastewater standards and offers an effective alternative to traditional treatment technologies that simply remove nutrients. Approximately 84% of total P and 97% of total Kjeldahl N entering a treatment plant can be captured (accounting for primary clarifier removal), whereas most existing technologies target side streams that typically contain only 20–30% of influent P and 15–20% of influent N

Neutrino Electromagnetic Form Factor and Oscillation Effects on Neutrino Interaction With Dense Matter

The mean free path of neutrino - free electron gas interaction has been calculated by taking into account the neutrino electromagnetic form factors and the possibility of neutrino oscillation. It is shown that the form factor effect becomes significant for a neutrino magnetic moment \mu_\nu > 10^{-10} mu_B and for a neutrino radius R > 10^{-6} MeV^{-1}. The mean free path is found to be sensitive to the nu_e-nu_mu and nu_e-nu_e^R transition probabilities.Comment: 4 pages, 3 eps figures, accepted for publication in Phys. Rev.

Neutron Fraction and Neutrino Mean Free Path Predictions in Relativistic Mean Field Models

The equation of state (EOS) of dense matter and neutrino mean free path (NMFP) in a neutron star have been studied by using relativistic mean field models motivated by effective field theory (ERMF). It is found that the models predict too large proton fractions, although one of the models (G2) predicts an acceptable EOS. This is caused by the isovector terms. Except G2, the other two models predict anomalous NMFP. In order to minimize the anomaly, besides an acceptable EOS, a large M* is favorable. A model with large M* retains the regularity in the NMFP even for a small neutron fraction.Comment: 4 pages, 5 figures, accepted for publication in Phys. Rev.

Neutrino Electromagnetic Form Factors Effect on the Neutrino Cross Section in Dense Matter

The sensitivity of the differential cross section of the interaction between neutrino-electron with dense matter to the possibly nonzero neutrino electromagnetic properties has been investigated. Here, the relativistic mean field model inspired by effective field theory has been used to describe non strange dense matter, both with and without the neutrino trapping. We have found that the cross section becomes more sensitive to the constituent distribution of the matter, once electromagnetic properties of the neutrino are taken into account. The effects of electromagnetic properties of neutrino on the cross section become more significant for the neutrino magnetic moment mu_nu > 10^{-10} mu_B and for the neutrino charge radius R > 10^{-5} MeV^{-1}.Comment: 24 pages, 10 figures, submitted to Physical Review

Comparison of toughened composite laminates using NASA standard damage tolerance tests

The proposed application of composite materials to transport wing and fuselage structures prompted the search for tougher materials having improved resistance to impact damage and delamination. Several resin/graphite fiber composite materials were subjected to standard damage tolerance tests and the results were compared to ascertain which materials have superior toughness. In addition, test results from various company and NASA laboratories were compared for repeatability

Fabry-Perot Measurements of the Dynamics of Globular Cluster Cores: M15 (NGC~7078)

We report the first use of the Rutgers Imaging Fabry-Perot Spectrophotometer to study the dynamics of the cores of globular clusters. We have obtained velocities for cluster stars by tuning the Fabry-Perot to take a series of narrow-band images at different wavelengths across one of the Na D (5890 AA) absorption lines. Measuring the flux in every frame yields a short portion of the spectrum for each star simultaneously. This proves to be a very efficient method for obtaining accurate stellar velocities; in crowded regions we are able to measure hundreds of velocities in 3-4 hours of observing time. We have measured velocities with uncertainties of less than 5 km/s for 216 stars within 1.5' of the center of the globular cluster M15 (NGC 7078). The paper is a uuencoded compressed postscript file