Direct Improvement of Hamiltonian Lattice Gauge Theory

We demonstrate that a direct approach to improving Hamiltonian lattice gauge theory is possible. Our approach is to correct errors in the Kogut-Susskind Hamiltonian by incorporating additional gauge invariant terms. The coefficients of these terms are chosen so that the order $a^2$ classical errors vanish. We conclude with a brief discussion of tadpole improvement in Hamiltonian lattice gauge theory.Comment: 9 page

Health Savings Account - Eligible High Deductible Health Plans: Updating the Definition of Prevention

High-deductible health plans (HDHPs) are an important and growing part of the health insurance landscape. By some estimates, as many as 80 percent of large employers may offer an HDHP in 2014. In 2013, more than 15 million Americans received health coverage through an HDHP, a more than a threefold increase since 2007.As outlined by the U.S. Treasury Department, individuals with an HSA-eligible HDHP are required to pay the full cost of most medications and services -- in theory utilizing pre-tax HSA funds -- until deductibles are met. However, the 2003 authorizing legislation and further guidance include a safe harbor allowing plans to cover primary preventive services, those typically deemed to prevent the onset of disease, before the deductible is satisfied.Services or benefits meant to treat "an existing illness, injury or condition," are excluded from first-dollar coverage in HSA-eligible HDHPs, which encompasses most secondary preventive services. For example, plans are prohibited from providing first dollar coverage of disease management services such as insulin, eye and foot exams, and glucose monitoring supplies for patients with diabetes.As chronic disease conditions currently make up 75 percent of total U.S. health spending, appropriate chronic disease management is an important tool to lower long-term health care costs. As the market for HDHPs grow, it is important that they maintain the flexibility to allow for effective health management of all beneficiaries. This report addresses the strict definition of prevention that an HDHP must follow for it to include a pre-tax health savings account (HSA), and how this restriction limits the effectiveness of current plans. A potential solution - allowing HSA-eligible HDHPs to provide first-dollar coverage for targeted, evidence-based, secondary preventive services that prevent chronic disease progression and related complications - can improve patient-centered outcomes, add efficiency to medical spending, and enhance HDHP attractiveness.A multi-disciplinary research team from the University of Michigan's Center for Value-Based Insurance Design, Harvard Medical School, and the University of Minnesota conducted a multi-part project to investigate the impact of updatingthe definition of prevention for HDHPs to include selected secondary preventive services that are frequently used as health plan quality metrics and included as elements of pay-for-performance programs. Specifically, the project aimed to: 1) determine the premium effect, actuarial value, and estimated market uptake of the novel HDHP plan that covers these evidence-based services outside the deductible, and 2) explore through interviews whether insurance industry experts found coverage of secondary preventive services a worthwhile endeavor

How hosts control worms

No abstract available

A Green's function approach to transmission of massless Dirac fermions in graphene through an array of random scatterers

We consider the transmission of massless Dirac fermions through an array of short range scatterers which are modeled as randomly positioned $\delta$- function like potentials along the x-axis. We particularly discuss the interplay between disorder-induced localization that is the hallmark of a non-relativistic system and two important properties of such massless Dirac fermions, namely, complete transmission at normal incidence and periodic dependence of transmission coefficient on the strength of the barrier that leads to a periodic resonant transmission. This leads to two different types of conductance behavior as a function of the system size at the resonant and the off-resonance strengths of the delta function potential. We explain this behavior of the conductance in terms of the transmission through a pair of such barriers using a Green's function based approach. The method helps to understand such disordered transport in terms of well known optical phenomena such as Fabry Perot resonances.Comment: 22 double spaced single column pages. 15 .eps figure

A Mechanism for Ordinary-Sterile Neutrino Mixing

Efficient oscillations between ordinary (active) and sterile neutrinos can occur only if Dirac and Majorana mass terms exist which are both small and comparable. It is shown that this can occur naturally in a class of string models, in which higher-dimensional operators in the superpotential lead to an intermediate scale expectation value for a scalar field and to suppressed Dirac and Majorana fermion masses.Comment: 12 page

Implications of mirror neutrinos for early universe cosmology

The Exact Parity Model (EPM) is, in part, a theory of neutrino mass and mixing that can solve the atmospheric, solar and LSND anomalies. The central feature of the neutrino sector is three pairs of maximally mixed ordinary and mirror neutrinos. It has been shown that ordinary-mirror neutrino oscillations can generate large neutrino asymmetries in the epoch of the early universe immediately prior to Big Bang Nucleosynthesis (BBN). The large neutrino asymmetries generically suppress the production of mirror neutrinos, and a sufficiently large $\nu_e$ asymmetry can directly affect light element synthesis through nuclear reaction rates. In this paper we present a detailed calculation of neutrino asymmetry evolution driven by the six-flavour EPM neutrino sector, focusing on implications for BBN.Comment: Latex, about 55 pages long with some figure

Radiative neutrino mass generation and dark energy

We study the models with radiative neutrino mass generation and explore the relation between the neutrino masses and dark energy. In these models, the pseudo-Nambu-Goldston bosons (pNGBs) arise at two-loop level via the Majorana neutrino masses. In particular, we demonstrate that the potential energy of the pNGB can be the dark energy potential and the observed value of the equation of state (EoS) parameter of the universe, $i.e.$, $w\simeq -1$, can be realized.Comment: 10 pages, 1 figure, a minor correction in Eq. (17

Grain Surface Models and Data for Astrochemistry

AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∼25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions

Targeted kinase inhibition relieves slowness and tremor in a Drosophila model of LRRK2 Parkinson’s disease

Disease models: A reflex reaction A simple reflex in flies can be used to test the effectiveness of therapies that slow neurodegeneration in Parkinson’s disease (PD). Christopher Elliott and colleagues at the University of York in the United Kingdom investigated the contraction of the proboscis muscle which mediates a taste behavior response and is regulated by a single dopaminergic neuron. Flies bearing particular mutations in the PD-associated gene leucine-rich repeat kinase 2 (LRRK2) in dopaminergic neurons lost their ability to feed on a sweet solution. This was due to the movement of the proboscis muscle becoming slower and stiffer, hallmark features of PD. The authors rescued the impaired reflex reaction by feeding the flies l-DOPA or LRRK2 inhibitors. These findings highlight the proboscis extension response as a useful tool to identify other PD-associated mutations and test potential therapeutic compounds