Intensive versus Extensive Dairy Production Systems: Dairy States in the Eastern and Midwestern U.S. and Key Pasture Countries the E.U.: Determining the Competitive Edge

In recent years, significant structural and production system changes have been noted in the U.S. and European Union, as well as increased interest in pasture-based dairy systems. Technical efficiency, returns to scale, and farm characteristics are compared by size and production system in traditional U.S. dairy states and E.U. countries.U.S., EU Countries, Dairy Systems, Technical Efficiency, Returns To Scale, Size, Technology, Land Prices, Production Economics, Q12,

Economic Efficiency of U.S. Organic Versus Conventional Dairy Farms: Evidence from 2005 and 2010

We estimate an input distance function for U.S. dairy farming to examine the competitiveness of organic and non-organic dairy production by system and size. Across organic/non-organic systems and size classes, size is the major determinant of competitiveness based on various measures of productivity and returns to scale.Organic, Non-organic, Input Distance Function, Livestock Production/Industries, Production Economics,

Robust Trapped-Ion Quantum Logic Gates by Continuous Dynamical Decoupling

We introduce a novel scheme that combines phonon-mediated quantum logic gates in trapped ions with the benefits of continuous dynamical decoupling. We demonstrate theoretically that a strong driving of the qubit decouples it from external magnetic-field noise, enhancing the fidelity of two-qubit quantum gates. Moreover, the scheme does not require ground-state cooling, and is inherently robust to undesired ac-Stark shifts. The underlying mechanism can be extended to a variety of other systems where a strong driving protects the quantum coherence of the qubits without compromising the two-qubit couplings.Comment: Slightly longer than the published versio

Forage Outsourcing in the Dairy Sector: The Extent of Use and Impact on Farm Profitability

The extent of forage purchasing behavior in milk production and its impact on profitability are analyzed using data from the 2000 and 2005 dairy versions of the Agricultural Resource Management Survey. Forage outsourcing is more common with hay than with silage and haylage, and is more prevalent in the western United States. Though silage and haylage outsourcing is found to impact profitability, the major profitability drivers appear to be farm size and efficiency. Evidence of significant forage contracting is found in the western United States.forage, input purchasing, outsourcing, contracting, milk production, Farm Management, Industrial Organization, Livestock Production/Industries,

Small U.S. Dairy Farms: Can They Compete?

The U.S. dairy industry is undergoing rapid structural change, evolving from a structure including many small farmers in the Upper Midwest and Northeast to one that includes very large farms in new production regions. Small farms are struggling to retain competitiveness via improved management and low-input systems. Using data from USDA’s Agricultural Resource Management Survey, we determine the extent of U.S. conventional and pasture-based milk production during 2003-2007, and estimate net returns, scale efficiency, and technical efficiency associated with the systems across different operation sizes. We compare the financial performance of small conventional and pasture-based producers with one another and with largescale producers. A stochastic production frontier is used to analyze performance over the period for conventional and pasture technologies identified using a binomial logit model. Large conventional farms generally outperformed smaller farms using most economic measures – technical efficiency, various profitability measures, and returns to scale.Pasture-based system, technical efficiency, returns to scale, dairy, Livestock Production/Industries, Productivity Analysis,

Variation of turbulent burning rate of methane, methanol, and iso-octane air mixtures with equivalence ratio at elevated pressure

Turbulent burning velocities for premixed methane, methanol, and iso-octane/air mixtures have been experimentally determined for an rms turbulent velocity of 2 m/s and pressure of 0.5 MPa for a wide range of equivalence ratios. Turbulent burning velocity data were derived using high-speed schlieren photography and transient pressure recording; measurements were processed to yield a turbulent mass rate burning velocity, utr. The consistency between the values derived using the two techniques, for all fuels for both fuel-lean and fuel-rich mixtures, was good. Laminar burning measurements were made at the same pressure, temperature, and equivalence ratios as the turbulent cases and laminar burning velocities and Markstein numbers were determined. The equivalence ratio (φ) for peak turbulent burning velocity proved not always coincident with that for laminar burning velocity for the same fuel; for isooctane, the turbulent burning velocity unexpectedly remained high over the range φ = 1 to 2. The ratio of turbulent to laminar burning velocity proved remarkably high for very rich iso-octane/air and lean methane/air mixtures

Pasture-Based Dairy Systems: Who Are the Producers and Are Their Operations More Profitable than Conventional Dairies?

U.S. dairy operations are sorted via a multinomial logit model into three production systems: pasture-based, semi-pasture-based, and conventional. Region, farm size, financial situation, and production intensity measures impact system choice. Analysis follows to determine the impact of production system on enterprise profitability. Region, farm size, and demographic variables impact profitability, as does system choice: semi-pasture-based operations were less profitable than conventional operations on an enterprise, per hundredweight of milk produced basis. Significant differences were not found in the profitability of pasture-based operations versus those using other systems.dairy farm size, grazing, pasture-based dairying, Livestock Production/Industries,

Inelastic final-state interaction

The final-state interaction in multichannel decay processes is sytematically studied with application to B decay in mind. Since the final-state inteaction is intrinsically interwoven with the decay interaction in this case, no simple phase theorem like "Watson's theorem" holds for experimentally observed final states. We first examine in detail the two-channel problem as a toy-model to clarify the issues and to remedy common mistakes made in earlier literature. Realistic multichannel problems are too challenging for quantitative analysis. To cope with mathematical complexity, we introduce a method of approximation that is applicable to the case where one prominant inelastic channel dominates over all others. We illustrate this approximation method in the amplitude of the decay B to pi K fed by the intermediate states of a charmed meson pair. Even with our approximation we need more accurate information of strong interactions than we have now. Nonethless we are able to obtain some insight in the issue and draw useful conclusions on general fearyres on the strong phases.Comment: The published version. One figure correcte

Stronger computational modelling of signalling pathways using both continuous and discrete-state methods

Starting from a biochemical signalling pathway model expresses in a process algebra enriched with quantitative information, we automatically derive both continuous-space and discrete-space representations suitable for numerical evaluation. We compare results obtained using approximate stochastic simulation thereby exposing a flaw in the use of the differentiation procedure producing misleading results

Enhancement of the stability of genetic switches by overlapping upstream regulatory domains

We study genetic switches formed from pairs of mutually repressing operons. The switch stability is characterised by a well defined lifetime which grows sub-exponentially with the number of copies of the most-expressed transcription factor, in the regime accessible by our numerical simulations. The stability can be markedly enhanced by a suitable choice of overlap between the upstream regulatory domains. Our results suggest that robustness against biochemical noise can provide a selection pressure that drives operons, that regulate each other, together in the course of evolution.Comment: 4 pages, 5 figures, RevTeX