Summary Account of the Carolina Parakeet in Arkansas

The extinct Carolina Parakeet (Conuropsis carolinensis) once was part of the Arkansas avifauna. The first two reports of the species in what is now Arkansas were made in 1673 and 1718 by early French explorers. The remaining records are from the 1800s when parakeets were found in nearly all parts of the state, often in abundance. The last literature reference for the species still definitely occurring in Arkansas pertains to birds present in the summer of 1885 along the White River at Newpor

Real Cubic Surfaces and Real Hyperbolic Geometry

The moduli space of stable real cubic surfaces is the quotient of real hyperbolic four-space by a discrete, nonarithmetic group. The volume of the moduli space is 37\pi^2/1080 in the metric of constant curvature -1. Each of the five connected components of the moduli space can be described as the quotient of real hyperbolic four-space by a specific arithmetic group. We compute the volumes of these components.Comment: 4 pages, one figur

Hyperbolic geometry and moduli of real cubic surfaces

Let M_0^R be the moduli space of smooth real cubic surfaces. We show that each of its components admits a real hyperbolic structure. More precisely, one can remove some lower-dimensional geodesic subspaces from a real hyperbolic space H^4 and form the quotient by an arithmetic group to obtain an orbifold isomorphic to a component of the moduli space. There are five components. For each we describe the corresponding lattices in PO(4,1). We also derive several new and several old results on the topology of M_0^R. Let M_s^R be the moduli space of real cubic surfaces that are stable in the sense of geometric invariant theory. We show that this space carries a hyperbolic structure whose restriction to M_0^R is that just mentioned. The corresponding lattice in PO(4,1), for which we find an explicit fundamental domain, is nonarithmetic.Comment: Major revision, including several new or completely rewritten sections. 56 page

Ambipolar diffusion in smoothed particle magnetohydrodynamics

In partially ionised plasmas, the magnetic field can become decoupled from the neutral gas and diffuse through it in a process known as ambipolar diffusion. Although ambipolar diffusion has been implemented in several grid codes, we here provide an implementation in smoothed particle magnetohydrodynamics (SPMHD). We use the strong coupling approximation in which the ion density is negligible, allowing a single fluid approach. The equations are derived to conserve energy, and to provide a positive definite contribution to the entropy. We test the implementation in both a simple 1D SPMHD code and the fully 3D code PHANTOM. The wave damping test yields agreement within 0.03-2 per cent of the analytical result, depending on the value of the collisional coupling constant. The oblique C-shocks test yields results that typically agree within 4 per cent of the semi-analytical result. Our algorithm is therefore suitable for exploring the effect ambipolar diffusion has on physical processes, such as the formation of stars from molecular clouds.Comment: Accepted for publication by MNRA

THE WELFARE EFFECTS OF CONSUMING A CANCER PREVENTION DIET

This study measures the welfare changes in agriculture and to consumers should people eat the recommended levels of fruits and vegetables for a cancer prevention diet. An equilibrium displacement model is used to measure the change in welfare to fruit and vegetable industries, other commodities, and agricultural input markets.Food Consumption/Nutrition/Food Safety,

Linkages Between Greater Fruit and Vegetable Consumption and Agriculture

This study will estimate the benefits to fruit and vegetable industries and consumers should people in the U.S. meet the USDA minimum dietary guidelines. Specifically the objectives of the study are to 1) estimate the benefits to fruit and vegetable industries and consumers should people eat the general and subgroup 7-a-day and 9-a-day recommendation; 2) estimate the benefits should smaller increases of only 10 percent or 25 percent be achieved; and 3) determine how agricultural inputs, including land and labor, would be affected by the increase in demand for fruits and vegetables. To protect against the incidence of chronic diseases such as diabetes, cardiovascular disease and cancer the 2005 USDA dietary guidelines recommend the consumption of 3 to 4 fruit servings and 4 to 5 vegetable servings a day. They also provide recommendations on the composition of fruit and vegetable consumption as well as the level. For example, almost one serving of dark leafy vegetables is recommended per day. Depite the known health benefits, many people do not eat the amounts recommended in the USDA dietary guidelines and low income consumers (those whose median household income is less than $25,000 a year) eat fewer servings. Based on the NHANES4 (National health and nutrition examination survey) and NHANES5, average consumption of fruit by low-income consumers would need to increase by at least 83 percent at meet the 3 a day recommendation and 39 percent in order to meet the 4 a day recommendation. People in higher-income households only need to increase consumption by only 60 percent for fruit and 30 percent for vegetables. The proportional increases in consumption assume that people no longer eat potato chips or french fries in order to meet dietary guidelines on fat consumption. A shift in consumption patterns to the recommended levels would cause the demand for fruits and vegetables to rise significantly, leading to higher prices and increased production, shifting the use of agricultural resources (such as land, labor, and water) into the production of those commodities, and benefiting the entire agricultural sector. Despite the potential gains to agriculture, these values have been ignored in previous studies of improved nutrient intake. Such a benefit to producers might justify additional public sector investment in promoting healthier diets. The changes in prices, agricultural production, agricultural input usage, and trade will be simulated using an equilibrium displacement model. The dual approach used in this analysis lays out basic demand and supply equations from demand and cost functions to show how equilibrium conditions change in response to shocks, such as an increase in the demand for fruits and vegetables. The functions characterize the final market, allow for substitutability between marketing and non-marketing inputs in the marketing sector, includes the farm sector, and changes in input use resulting from changes in crop mix and substitutability in land, labor and other inputs. Equilibrium displacement models have been widely used to estimate the benefits of agricultural research agricultural policies and the benefits to the dairy industry of a social marketing program to middle school children. The model is parameterized with farm, market and consumption data. The increase in fruit and vegetable consumption is modeled as a shift in the demand curve with the shift equal to the percentage increase needed to meet the USDA dietary guidelines. Producer surplus is estimated from the changes in grower prices and agricultural production, less changes in the cost of inputs. Consumer surplus for people living in low-income households (less than$25,000 a year median income) and higher income households is estimated from the changes in retail prices and final market quantities consumed by each income group.Food Consumption/Nutrition/Food Safety,