The development of capitalism

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Bird and rodent pest control in select California crops: economic contributions, impacts, and benefits

2014 Fall.Includes bibliographical references.Although numerous factors affect agriculture production, significant yield and quality losses of crops have been attributed to wildlife, insects, and diseases; collectively known as pests. To mitigate pest activity agricultural producers utilize a variety of control tools and techniques including rodenticides, trapping, exclusion, and chemical aversion (Sexton et al., 2007); causing integrated pest management to become an integral part of modern agricultural production. Although crop savings is arguably the most important contribution of pest control, relatively few studies have attempted to quantify prevented crop loss and the economic impacts of these cost savings. This study found that current California control practices as applied to alfalfa, almonds, avocados, carrots, cherries, citrus, grapes, lettuce, melons, peaches, pistachios, rice, strawberries, tomatoes, and walnuts were effective at mitigating crop loss which had the potential to significantly restrict the domestic supply of these agricultural commodities. These practices were shown to lower wholesale prices and were estimated to prevent multi-million dollar losses to California growers, and multi-billion dollar losses to consumers nationwide. In addition to the direct benefits realized through these crop savings, the production and sale of these additional yields further stimulates economic activity within the state. Modeling the forward and backward linkages between California suppliers and consumers enabled monetary flows in secondary markets to be quantified, providing a more conclusive estimate of the total benefits of bird and rodent control in California. This study found that expenditures related to the production of additional yields protected from rodent damage contributed $1.7 billion to California's economy and supported 23,000 jobs, with farm revenue earned on these yields supporting another 11,000 California jobs and contributing nearly$951 million to the state's economy. Findings from this study also estimated that the production of yields protected from bird damage were estimated to contribute $1.39 billion to the state's economy and supported more than 20,000 jobs, with farm revenue earned on these yields supporting another 6,775 jobs and contributing another$565 million to California's economy

Fibre gratings in novel optical fibres for applications in sensing

This thesis presents the fabrication of fibre gratings in novel optical fibres for sensing applications. Long period gratings have been inscribed into photonic crystal fibre using the electric-arc technique. The resulting sensing characteristics were found to depend on the air-hole geometry of the particular fibre. This provides the potential of designing a fibre to have enhanced sensitivity to a particular measure and whilst removing unwanted cross sensitivities. Fibre Bragg gratings have been fabricated in a variety of polymer optical fibres, including microstructured polymer optical fibre, using a continuous wave helium cadmium laser. The thermal response of the gratings have been characterised and found to have enhanced sensitivity compared to fibre Bragg gratings in silica optical fibre. The increased sensitivity has been harnessed to achieve a grating based device in single mode step index polymer optical fibre by fabricating an electrically tunable fibre Bragg grating. This was accomplished by coating the grating region in a thin layer of copper, which upon application of a direct current, causes a temperature induced Bragg wavelength shift

Electrically tunable Bragg gratings in single mode polymer optical fiber

We present what is to our knowledge the first demonstration of a tunable fiber Bragg grating device in polymer optical fiber that utilizes a thin-film resistive heater deposited on the surface of the fiber. The polymer fiber was coated via photochemical deposition of a Pd/Cu metallic layer with a procedure induced by vacuum-ultraviolet radiation at room temperature. The resulting device, when wavelength tuned via joule heating, underwent a wavelength shift of 2 nm for a moderate input power of 160 mW, a wavelength to input power coefficient of-13.4 pm/mW, and a time constant of 1.7 s-1

Temperature-insensitive long period grating sensors in photonic crystal fibre

A long period grating has been fabricated in endlessly single-mode photonic crystal fibre using a spatially-periodic electric arc discharge. The sensing characteristics of the grating have been studied and it was found to possess an insensitivity to temperature, a bend sensitivity of 3.7 nm · m and a strain sensitivity of -2.0 pm/µe

Collective and Family Agriculture in Socialist Economies

summary This article analyses existing theories concerning the relationship between private and collective agricultural sectors in socialist economies with special reference to Vietnam. Dong argues that the household sector retains its vitality within socialist agriculture since it is a distinct and historically necessary mode of mobilising surplus labour and should be seen as playing a developmentally desirable role in both the rural reproduction process and surplus accumulation. Resumen La agricultura colectiva y familiar en economies socialistas Mediante este articulo se analizan las teorias actuales concernientes a la relación entre los sectores agricoles privados y colectivos dentro de economias socialistas, con referencia especiai al Vietnam. Dong argumenta que el sector familiar retiene su vitalidad dentro de la agricultura socialista, puesto que constituye un modo distinto e históricamente necesario, de movilizar la mano de obra excedente y deberia interpretarse como emprendedor de una misión deseable en cuanto al desarrollo, tanto dentro del proceso rural de reproducción como en la acumulación de excedentes. Résumé L'agriculture familiale et collective dans les économies socialistes Cet article analyse les théories actuelles concernant les relations entre les secteurs agricoles privés et collectifs dans les économies socialistes avec une référence spéciale au Vietnam. Dong démontre que le secteur familial conserve sa vitalité au sein de l'agriculture socialiste dès lors que c'est un mode distinct et historiquement nécessaire de mobilisation de surplus de main?d'oeuvre et qu'il devrait être considéré comme ayant un rôle désirable à jouer dans le développement à la fois du processus de reproduction rurale et de surplus d'accumulation

Evolutionary Model of the Personal Income Distribution

The aim of this work is to establish the personal income distribution from the elementary constituents of a free market; products of a representative good and agents forming the economic network. The economy is treated as a self-organized system. Based on the idea that the dynamics of an economy is governed by slow modes, the model suggests that for short time intervals a fixed ratio of total labour income (capital income) to net income exists (Cobb-Douglas relation). Explicitly derived is Gibrat's law from an evolutionary market dynamics of short term fluctuations. The total private income distribution is shown to consist of four main parts. From capital income of private firms the income distribution contains a lognormal distribution for small and a Pareto tail for large incomes. Labour income contributes an exponential distribution. Also included is the income from a social insurance system, approximated by a Gaussian peak. The evolutionary model is able to reproduce the stylized facts of the income distribution, shown by a comparison with empirical data of a high resolution income distribution. The theory suggests that in a free market competition between products is ultimately the origin of the uneven income distribution