Do Theoretical Restrictions Matter for the Translog Stochastic Production Function? Evidence from the Kansas Farm Sector

Farm Management, Production Economics, Productivity Analysis,

An Analysis of Efficiency of Midwestern Agricultural Cooperatives

Agribusiness,

Autonomous Real Time Architecture for High Performance Mobile Robots

Highly-dynamic robotic systems, such as hopping robots, require light, computationally and energy efficient on-board units for control. This paper presents such a computational unit together with a software architecture for achieving high-performance behaviors, such as balancing and hopping. These demanding behaviors require accurate dynamic calculations, high-bandwidth control, and fast real-time state estimation. The proposed system consists of cheap and off-the-shelf electronics that are detailed in this paper. The effectiveness of the presented approach is validated on a balancing machine called Tippy, which is able to achieve fast tracking of command signals while balancing. The experimental results of this paper demonstrate that reliable real-time software for demanding high-performance robotic applications, which require fast control loops and intensive calculations, can be achieved with light, low cost and energy efficient components, which can empower the widespread use and experimentation of high-performance robots worldwide

Height Systems and Vertical Datums: a Review in the Australian Context

This paper reviews (without equations) the various definitions of height systems and vertical geodetic datum surfaces, together with their practical realisation for users in Australia. Excluding geopotential numbers, a height system is a one-dimensional coordinate system used to express the metric distance (height) of a point from some reference surface. Its definition varies according to the reference surface chosen and the path along which the height is measured. A vertical geodetic datum is the practical realisation of a height system and its reference surface for users, nominally tied to mean sea level. In Australia, the normal-orthometric height system is used, which is embedded in the Australian Height Datum (AHD). The AHD was realised by the adjustment of ~195,000 km of spirit-levelling observations fixed to limited-term observations of mean sea level at multiple tide-gauges. The paper ends by giving some explanation of the problems with the AHD and of the differences between the AHD and the national geoid model, pointing out that it is preferable to recompute the AHD

Cash operating income and liquidity management for feeder cattle operations

Net cash flow measures the amount of cash remaining after all cash expense obligations are satisfied. This cash is available for additional farm investment, off-farm investment, family living, and additional debt repayment. A 5-year, average, monthly, cash-flow statement was used to determine net cash flow for 18 feeder cattle farms .Results indicate that excess cash was used primarily to invest in equipment, vehicles, and nonfarm assets. Investments in buildings increased moderately over the study period, while investment in land was minimal

The Divisive Power of Humour: Comedy, Taste and Symbolic Boundaries

Using British and Dutch interview data, this article demonstrates how people from different social classes draw strong symbolic boundaries on the basis of comedy taste. Eschewing the omnivorousness described in recent studies of cultural consumption, comedy audiences make negative aesthetic and moral judgements on the basis of comedy taste, and often make harsh judgements without the disclaimers, apologies and ambivalence so typical of ‘taste talk’ in contemporary culture. The article demonstrates how, in particular, Dutch and British middle class audiences use their comedy taste to communicate distinction and cultural superiority. We discuss several reasons why such processes of social distancing exist in comedy taste and not other cultural areas: the traditionally low status of comedy; the strong relation between humour and personhood; the continuity between comedy tastes and humour styles in everyday life; as well as the specific position of comedy in the British and Dutch cultural fields

A Synthetic Earth Gravity Model Designed Specifically for Testing Regional Gravimetric Geoid Determination Algorithms

A synthetic [simulated] Earth gravity model (SEGM) of the geoid, gravity and topography has been constructed over Australia specifically for validating regional gravimetric geoid determination theories, techniques and computer software. This regional high-resolution (1-arc-min by 1-arc-min) Australian SEGM (AusSEGM) is a combined source and effect model. The long-wavelength effect part (up to and including spherical harmonic degree and order 360) is taken from an assumed errorless EGM96 global geopotential model. Using forward modelling via numerical Newtonian integration, the short-wavelength source part is computed from a high-resolution (3-arc-sec by 3-arc-sec) synthetic digital elevation model (SDEM), which is a fractal surface based on the GLOBE v1 DEM. All topographic masses are modelled with a constant mass-density of 2,670 kg/m3. Based on these input data, gravity values on the synthetic topography (on a grid and at arbitrarily distributed discrete points) and consistent geoidal heights at regular 1-arc-min geographical grid nodes have been computed. The precision of the synthetic gravity and geoid data (after a first iteration) is estimated to be better than 30 μ Gal and 3 mm, respectively, which reduces to 1 μ Gal and 1 mm after a second iteration.The second iteration accounts for the changes in the geoid due to the superposed synthetic topographic mass distribution. The first iteration of AusSEGM is compared with Australian gravity and GPS-levelling data to verify that it gives a realistic representation of the Earth’s gravity field. As a by-product of this comparison, AusSEGM gives further evidence of the north–south-trending error in the Australian Height Datum. The freely available AusSEGM-derived gravity and SDEM data, included as Electronic Supplementary Material (ESM) with this paper, can be used to compute a geoid model that, if correct, will agree to in 3 mm with the AusSEGM geoidal heights, thus offering independent verification of theories and numerical techniques used for regional geoid modelling