FARM: A Global Framework for Integrated Land Use/Cover Modeling

The Future Agricultural Resources Model (FARM) was developed by the U.S. Department of Agriculture's Economic Research Service (ERS) to evaluate effects of global changes on agricultural systems. The model uses a geographic information system that links climatically defined land and water resources with production possibilities in 12 regions, and an economic model that simulates how changes in one region can affect land and water resources as well as production and consumption of 13 aggregate commodities in eight regions. Analyses carried out with FARM show that: 1) global climate change and population growth are likely to place additional stress on current agricultural and environmental systems during the 21st century; 2) the net economic effects of global climate change may be positive but realization of these benefits may increase environmental stresses; 3) deregulation of trade in agricultural commodities may help to alleviate some of the economic pressure generated by population growth and global climate change and 4) setting land aside from economic production to protect natural ecosystems may have relatively low opportunity costs, but global climate change will make it more difficult to implement such programs

World Agriculture and Climate Change: Economic Adaptations

Recent studies suggest that possible global increases in temperature and changes in precipitation patterns during the next century will affect world agriculture. Because of the ability of farmers to adapt , however, these changes are not likely to imperil world food production. Nevertheless, world production of all goods and services may decline, if climate change is severe enough or if cropland expansion is hindered. Impacts are not equally distributed around the world.climate change, world agriculture, Environmental Economics and Policy,

Non-optimality of the Greedy Algorithm for subspace orderings in the method of alternating projections

The method of alternating projections involves projecting an element of a Hilbert space cyclically onto a collection of closed subspaces. It is known that the resulting sequence always converges in norm and that one can obtain estimates for the rate of convergence in terms of quantities describing the geometric relationship between the subspaces in question, namely their pairwise Friedrichs numbers. We consider the question of how best to order a given collection of subspaces so as to obtain the best estimate on the rate of convergence. We prove, by relating the ordering problem to a variant of the famous Travelling Salesman Problem, that correctness of a natural form of the Greedy Algorithm would imply that $\mathrm{P}=\mathrm{NP}$, before presenting a simple example which shows that, contrary to a claim made in the influential paper [Kayalar-Weinert, Math. Control Signals Systems, vol. 1(1), 1988], the result of the Greedy Algorithm is not in general optimal. We go on to establish sharp estimates on the degree to which the result of the Greedy Algorithm can differ from the optimal result. Underlying all of these results is a construction which shows that for any matrix whose entries satisfy certain natural assumptions it is possible to construct a Hilbert space and a collection of closed subspaces such that the pairwise Friedrichs numbers between the subspaces are given precisely by the entries of that matrix.Comment: To appear in Results in Mathematic

High Current Transformer

By reason of the fact that a thesis along the line of one's course or about some subject with which he is supposed to be familiar is required of every Senior electrical by the electrical department before his graduation, the following description of the design and construction of a 10 K.W., high current, welding transform er has been prepared and submitted to the faculty. This subject was chosen partly because of the practical experience to be gained in its design and construction, and partly because of the laboratory's need for such an apparatus, the high secondary current making the transformer one of the main adjuncts of an electric furnace. In the following description the general theory of transformers is explained as well as time and space permit, after which attention is turned to the particular apparatus under discussion

Influencia de la adición porcentual de fibras de penca de tuna en las propiedades del mortero, Huaraz – 2022

La presente investigación tuvo por objetivo general determinar la influencia de la adición porcentual de fibras de penca de tuna que mejore las propiedades del mortero, Huaraz – 2022; por lo que en cuanto a la metodología el tipo de investigación fue aplicada de diseño experimental, se tuvo como población 80 muestras donde se tuvo 20 ensayos de mortero convencional con adición de 0%, 1%, 2% y 3% respectivamente, cada adición fue evaluada en 4 periodos (3, 7, 14 y 28 días) contando con 5 muestras en cada periodo. Respecto a los resultados, se halló que el mejor porcentaje de adición de fibra de penca fue el 3%, arrojando una capacidad de absorción a los 3 días de 6,59737 y a los 28 días arrojando un valor de 6,78406, en cuanto a la resistencia a la comprensión a los 3 días arrojó un valor de 84,854 y a los 28 días arrojo un valor 101,994. De esta manera que se concluye que, influye la adición de fibras de penca de tuna significativamente en las propiedades del mortero, Huaraz – 2022, dado que en la capacidad de absorción y la resistencia de compresión se registró un p-valor < 0,0

Swine Trichinella Infection and Geographic Information System Tools

Pastured pigs are vulnerable to Trichinella spiralis infection through exposure to wild reservoir hosts. To evaluate the potential impact of the expanding production of pork from pasture-raised pigs, we mapped locations of T. spiralis occurrence and pastured-pig farms in the United States. Twenty-eight farms were located within 50 km of previous infection

Determinación del momento óptimo de saca de reproductores en cuyes criollos (Cavia porcellus)

In the Germplasm Bank of native guinea pigs of the EEA Chumbibamba of the National Institute of Agrarian Innovation (Peru) the optimal technical and economic moment for the single culling of breeding animals was determined. In total, 320 Creole guinea pigs were used and the Fisher-Hotelling methodology was applied, and the bioeconomic model of single harvest of breeding animals at constant price was proposed under four profitability rate scenarios. The results of the biological model indicate that the optimal productive life in females occurs at 414 days of age and in males at 579 days. The optimal values of the bioeconomic model for guinea pigs by profitability scenarios indicate that at a discount rate of 9%, the optimal harvest period would be 502 days; while at the discount rate of 30% it is reduced to 494 days.En el Banco de Germoplasma de cuyes nativos de la EEA Chumbibamba del Instituto Nacional de Innovación Agraria (Perú) se determinó el momento óptimo técnico y económico para la saca única de reproductores. Se utilizaron 320 cuyes criollos y se aplicó la metodología Fisher - Hotelling, se planteó el modelo bioeconómico de saca única de reproductores a precio constante bajo cuatro escenarios de tasas de rentabilidad. Los resultados del modelo biológico señalan que la vida productiva óptima en hembras ocurre a los 414 días de edad y en los machos a 579 días. Los valores óptimos del modelo bioeconómico para los cuyes por escenarios de rentabilidad señalan que a una tasa de descuento del 9% el periodo óptimo de saca sería a 502 días; mientras que a la tasa de descuento del 30% se reduce a 494 días

Effects of repetitive low-acceleration impacts on attitude estimation with micro-electromechanical inertial measurement units

Inertial Measurement Units are present in several applications in aerospace, unmanned vehicle navigation, legged robots, and human motion tracking systems, due to their ability to estimate a body’s acceleration, orientation and angular rate. In contrast to rovers and drones, legged locomotion involves repeated impacts between the feet and the ground, and rapid locomotion (e.g., running) involves alternating stance and flight phases, resulting in substantial oscillations in vertical acceleration. The aim of this research is to investigate the effects of periodic low-acceleration impacts (4 g, 8 g and 16 g), which imitate the vertical motion of a running robot, on the attitude estimation of multiple Micro-Electromechanical Systems IMUs. The results reveal the presence of a significant drift in the attitude estimation of the sensors, which can provide important information during the design process of a robot (sensor selection), or during the control phase (e.g., the system will know that after a series of impacts the attitude estimations will be inaccurate)

Syndactyly in Pigs: A Review of Previous Research and the Presentation of Eight Archaeological Specimens

This paper reviews evidence for the rare condition of porcine syndactyly. It describes eight archaeological examples from Britain, Northern Ireland and France. Syndactyly refers to the partial or complete fusion of two or more adjacent phalanges on the medio-lateral border. The degree and character of fusion are variable, but phalanges frequently unite to create a single skeletal element. This condition has been identified by veterinarians, zoologists and naturalists in individuals and populations in a range of species, but in spite of substantial research on the condition in humans and to a lesser extent cattle, it remains relatively poorly understood in other mammals. Syndactyly is generally agreed to be primarily congenital in origin, although factors affecting its incidence remain far from fully understood. In light of the general paucity of discussion of specific conditions of animal palaeopathology, this paper presents an analysis of these newly discovered syndactyle pig specimens, offers a review of research with particular reference to pigs and discusses the etiology of the condition