Orderly Production and Marketing in the Beef-Pork Sector

This study will present economic models for analyzing temporal equilibrium positions for the beef-pork sector. The issues of spatial distribution, storage, and meat forms will not be directly analyzed. Grade and yield changes for various carcass classes will, however, be implied in the carrying costs of the animal. The models will be designed such that a number of different factors that affect the production and marketing of beef and pork can be analyzed simultaneously

Structural Relationships for National and regional Beef Cattle Production

Changes have occurred in recent years which have produced changes in the beef industry. Structural relationships that existed for the producer-feeder are not necessarily important in the operation of the cow-calf operator or the feed-lot operator. Because of these changes, a more thorough knowledge of the supply response of a small regional breakdown of the beef cattle industry should be available to farmers, econmists, outlook workers and policy makers in the agricultural industry. The study examines cow-calf operations and feed-lot operations to investigate U.S. beef calf production and develop an economic model for number of beef calves produced by region in the U.S

Orderly Production and Marketing in the Beef-Pork Sector

This study will present economic models for analyzing temporal equilibrium positions for the beef-pork sector. The issues of spatial distribution, storage, and meat forms will not be directly analyzed. Grade and yield changes for various carcass classes will, however, be implied in the carrying costs of the animal. The models will be designed such that a number of different factors that affect the production and marketing of beef and pork can be analyzed simultaneously

New chondritic bodies identified in eight oxygen-bearing white dwarfs

We present observations and analyses of eight white dwarf stars that have accreted rocky material from their surrounding planetary systems. The spectra of these helium-atmosphere white dwarfs contain detectable optical lines of all four major rock-forming elements (O, Mg, Si, Fe). This work increases the sample of oxygen-bearing white dwarfs with parent body composition analyses by roughly thirty-three percent. To first order, the parent bodies that have been accreted by the eight white dwarfs are similar to those of chondritic meteorites in relative elemental abundances and oxidation states. Seventy-five percent of the white dwarfs in this study have observed oxygen excesses implying volatiles in the parent bodies with abundances similar to those of chondritic meteorites. Three white dwarfs have oxidation states that imply more reduced material than found in CI chondrites, indicating the possible detection of Mercury-like parent bodies, but are less constrained. These results contribute to the recurring conclusion that extrasolar rocky bodies closely resemble those in our solar system, and do not, as a whole, yield unusual or unique compositions.Comment: Accepted for publication in ApJ. 7 Figures, 7 Table

Soil biogeochemistry across Central and South American tropical dry forests

The availability of nitrogen (N) and phosphorus (P) controls the flow of carbon (C) among plants, soils, and the atmosphere, thereby shaping terrestrial ecosystem responses to global change. Soil C, N, and P cycles are linked by drivers operating at multiple spatial and temporal scales: landscape-level variation in macroclimate and soil geochemistry, stand-scale heterogeneity in forest composition, and microbial community dynamics at the soil pore scale. Yet in many biomes, we do not know at which scales most of the biogeochemical variation emerges, nor which processes drive cross-scale feedbacks. Here, we examined the drivers and spatial/temporal scales of variation in soil biogeochemistry across four tropical dry forests spanning steep environmental gradients. To do so, we quantified soil C, N, and P pools, extracellular enzyme activities, and microbial community structure across wet and dry seasons in 16 plots located in Colombia, Costa Rica, Mexico, and Puerto Rico. Soil biogeochemistry exhibited marked heterogeneity across the 16 plots, with total organic C, N, and P pools varying fourfold, and inorganic nutrient pools by an order of magnitude. Most soil characteristics changed more across space (i.e., among sites and plots) than over time (between dry and wet season samplings). We observed stoichiometric decoupling among C, N, and P cycles, which may reflect their divergent biogeochemical drivers. Organic C and N pool sizes were positively correlated with the relative abundance of ectomycorrhizal trees and legumes. By contrast, the distribution of soil P pools was driven by soil geochemistry, with larger inorganic P pools in soils with P-rich parent material. Most earth system models assume that soils within a texture class operate similarly, and ignore subgrid cell variation in soil properties. Here we reveal that soil nutrient pools and fluxes exhibit as much variation among four Neotropical dry forests as is observed across terrestrial ecosystems at the global scale. Soil biogeochemical patterns are driven not only by regional differences in soil parent material and climate, but also by local-scale variation in plant and microbial communities. Thus, the biogeochemical patterns we observed across the Neotropical dry forest biome challenge representation of soil processes in ecosystem models

Measuring Efficiency in the Beef-Pork Sector by Price Analysis

The price structure of the beef-pork sector from the retail level back to the primary production level is evaluated in order to identify areas of inefficient performance. Results indicated efficient pricing performance between the slaughter and the retail levels. Results between the ranch and feedlot levels indicated a weak and distorted price structure. This appeared to be due to the inability of the price system to serve both as a mechanism of trade and as a signal for the organization and timing of future production