Charmed scalar resonances -- Conventional and four-quark mesons

We propose that there coexist two scalar mesons of different structures (a conventional meson and a four-quark meson) in the recently observed broad bumps just below the large peak of the tensor meson in the D-pi mass distribution. We base this proposal on the interpretation of the charm-strange scalar meson of mass 2317 MeV as a four-quark meson. The strange counterparts of these scalar mesons are also studied.Comment: 4 pages, 0 figures, Revte

MODELING ALTERNATIVE POLICIES FOR GHG MITIGATION FROM FORESTRY AND AGRICULTURE

A key consideration for development of energy and climate policy affecting the forestry and agricultural sectors is that the selection of specific mechanisms implemented to achieve bioenergy production and/or greenhouse gas (GHG) mitigation targets may have substantial effects on landowner incentives to adopt alternative practices. For instance, the prices of allowances and offsets are expected to diverge under some policies being considered where there is a binding cap on the quantity of offsets from the agricultural and forest sectors. In addition, provisions that limit or exclude specific practices from receiving carbon payments will affect the quantity and cost of GHG mitigation opportunities available. In this study, the recently updated Forest and Agriculture Sector Optimization Model with GHGs (FASOMGHG) was used to estimate GHG mitigation potential for private land in the contiguous U.S. under a variety of GHG price policies. Model scenarios suggest that U.S. forestry and agriculture could provide mitigation of 200 – 1000 megatons carbon dioxide equivalent per year (Mt CO2e/year) at carbon prices of $15 to$50/tCO2e. Binding limits on offsets have increasingly large effects on both the total magnitude and distribution of GHG mitigation across options over time. In addition, discounting or excluding payments for forest sinks can reduce annualized land-based mitigation potential 37-90 percent relative to the full eligibility scenario whereas discounting or excluding agricultural practices reduces mitigation potential by less than 10 percent.Climate policy, energy policy, FASOMGHG, GHG mitigation, Agricultural and Food Policy, Environmental Economics and Policy, Resource /Energy Economics and Policy, C61, Q42, Q54,

Global Implications of U.S. Biofuels Policies in an Integrated Partial and General Equilibrium Framework

With the increasing research interests in biofuels, global implications of biofuels production have been generally examined either in a partial equilibrium (PE) or general equilibrium (GE) frameworks. Though both of these approaches have unique strengths, they also suffer from many limitations due to complexity of addressing all the relevant aspects of biofuels. In this paper we have exploited the strengths of both PE and GE approaches for analyzing the economic and environmental implications of the U.S. policies on corn-ethanol and biodiesel production. In this study, we utilize the Forest and Agricultural Sector Optimization Model (FASOMGHG: Adams et al. 1996, 2005; Beach et al. 2009), a non-linear programming, PE model for the United States. We also use the GTAP-BIO model (Birur et al. 2008), a multi-region, multi-sector CGE model for global-scale assessment of biofuels policies. Following Britz and Hertel (2009), we link the GTAP-BIO model through a static, quadratic restricted revenue function obtained from perturbing crop prices from the FASOMGHG model. With this linkage we implement the U.S. Corn ethanol and biodiesel scenarios in the GTAP-BIO model and obtain the FASOMGHG-consistent, global land use changes. The resulting crop price changes from the GE model are fed back into the FASOMGHG model to obtain the disaggregated impacts in the U.S.Biofuels, Indirect land use change, Land use emissions, Partial Equilibrium, Computable General Equilibrium, Land Economics/Use, Resource /Energy Economics and Policy,

Anisotropy and universality: Critical Binder cumulant of the two-dimensional Ising model

We reanalyze transfer matrix and Monte Carlo results for the critical Binder cumulant U* of an anisotropic two-dimensional Ising model on a square lattice in a square geometry with periodic boundary conditions. Spins are coupled between nearest neighboring sites and between next-nearest neighboring sites along one of the lattice diagonals. We find that U* depends only on the asymptotic critical long-distance features of the anisotropy, irrespective of its realization through ferromagnetic or antiferromagnetic next-nearest neighbor couplings. We modify an earlier renormalization-group calculation to obtain a quantitative description of the anisotropy dependence of U*. Our results support our recent claim towards the validity of universality for critical phenomena in the presence of a weak anisotropy.Comment: 4 pages, 2 figures; one reference and some clarifications adde

Doppler echocardiography assessment of impaired left ventricular filling in patients with right ventricular pressure overload due to primary pulmonary hypertension

In patients with primary pulmonary hypertension, competition between the right and left ventricles for the limited pericardial space results in distortion of left ventricular geometry reflected in displacement of the ventricular septum toward the left ventricular cavity. Left ventricular shape is most dramatically deranged at end-systole and early diastole, suggesting the possibility that the distribution of left ventricular diastolic filling might be altered. To investigate this hypothesis, nine patients with primary pulmonary hypertension and nine normal individuals were studied with echocardiographic techniques. Left ventricular isovolumic relaxation time was significantly prolonged in patients with primary pulmonary hypertension by comparison with normal individuals (129 ± 36 versus 53 ± 9 ms, p < 0.005) and the fraction of the transmitral flow velocity integral occurring in the first half of diastole was significantly less than in normal individuals (38 ± 14% versus 70 ± 9%, p < 0.005). Measurement of fractional changes in short-axis left ventricular cavity area similarly demonstrated that in patients with primary pulmonary hypertension fractional early diastolic cavity expansion (32 ± 11%) was significantly less than in normal individuals (78 ± 9%, p < 0.005).In patients with primary pulmonary hypertension, the ventricular septum was abnormally flattened toward the left ventricular cavity at end-systole (normalized septal curvature 0.04 ± 0.19) and remained that way throughout early diastolic filling but returned toward normal at end-diastole (normalized septal curvature 0.68 ± 0.19, p < 0.005). Thus, in patients with primary pulmonary hypertension end-systolic and early diastolic deformation of the left ventricle by septal flattening toward the left ventricular cavity is associated with relative underfilling of the left ventricle in early diastole and redistribution of left ventricular filling into late diastole. The reliance on late diastolic filling and atrial systole to maintain left ventricular preload in primary pulmonary hypertension may have important implications for the use of vasodilators in this disease

Landau Model for Commensurate-Commensurate Phase Transitions in Uniaxial Improper Ferroelectric Crystals

We propose the Landau model for lock-in phase transitions in uniaxially modulated improper ferroelectric incommensurate-commensurate systems of class I. It includes Umklapp terms of third and fourth order and secondary order parameter representing the local polarization. The corresponding phase diagram has the structure of harmless staircase, with the allowed wave numbers obeying the Farey tree algorithm. Among the stable commensurate phases only those with periods equal to odd number of lattice constants have finite macroscopic polarizations. These results are in excellent agreement with experimental findings in some A2BX4 compounds.Comment: 9 pages, 5 figures, revtex, to be published in Journal of Physics: Cond. Matter as a Letter to the Edito

Beyond the Death of Linear Response: 1/f optimal information transport

Non-ergodic renewal processes have recently been shown by several authors to be insensitive to periodic perturbations, thereby apparently sanctioning the death of linear response, a building block of nonequilibrium statistical physics. We show that it is possible to go beyond the ``death of linear response" and establish a permanent correlation between an external stimulus and the response of a complex network generating non-ergodic renewal processes, by taking as stimulus a similar non-ergodic process. The ideal condition of 1/f-noise corresponds to a singularity that is expected to be relevant in several experimental conditions.Comment: 4 pages, 2 figures, 1 table, in press on Phys. Rev. Let