Hydraulic limits on tree performance: Transpiration, carbon gain and growth of trees

An overview of the relationship between plant gas exchange, the potential hydraulic gradient, the size of the plant and its hydraulic conductance is presented. Key references are used to exemplify arguments of whole-plant optimality and to explain the origin and development of the dominant paradigm for interpreting the nature of water use and growth in plants.Resource /Energy Economics and Policy,

The African-American Intellectual of the 1920s: Some Sociological Implications of the Harlem Renaissance

This paper deals with some of the sociological implications of a major cultural high-water point in the African American experience, the New Negro/Harlem Renaissance. The paper concentrates on the cultural transformations brought about through the intellectual activity of political activists, a multi-genre group of artists, cultural brokers, and businesspersons. The driving-wheel thrust of this era was the reclamation and the invigoration of the traditions of the culture with an emphasis on both the, African and the American aspects, which significantly impacted American and international culture then and throughout the 20th century. This study examines the pre-1920s background, the forms of Black activism during the Renaissance, the modern content of the writers\u27 work, and the enthusiasm of whites for the African American art forms of the era. This essay utilizes research from a multi-disciplinary body of sources, which includes sociology, cultural history, creative literature and literary criticism, autobiography, biography, and journalism

Melvin universe as a limit of the C-metric

It is demonstrated that the Melvin universe representing the spacetime with a strong 'homogeneous' electric field can by obtained from the spacetime of two accelerated charged black holes by a suitable limiting procedure. The behavior of various invariantly defined geometrical quantities in this limit is also studied.Comment: 5 pages, no figures [v2: two references added

PRICE, YIELD, AND GROSS REVENUE VARIABILITY FOR SELECTED GEORGIA CROPS

Demand and Price Analysis,

A Study of the Image of Vocational Education in South Dakota Schools

Under the provisions of the Smith-Hughes Act and supplementary acts comprehensive program of vocational education have been developed. Although much has been accomplished, existing programs need to be expanded and new programs developed if vocational education is to be made available to all who can profit from the instruction. Vocational education does not take the place of general academic education, but rather supplements and enhances it for students who want specific training for a chosen occupation. Vocational education is an important part of a well-balanced school program and aims at developing competent economically, socially, emotionally, physically, and intellectually and in a civic sense. The percentage of unskilled workers required in the labor force is steadily declining: the percentage of skilled and semi-skilled worker is increasing. It is very important that the vocational education offered be based on the specific manpower needs of the nation. As these needs change, the program of vocational education must be adapted to meet the changes. This makes it necessary to continue changing vocational education programs by the adaptation of curriculums, courses, equipment, teacher education, the elimination of obsolete programs and the addition of new programs. Program planning can be used effectively by teachers, educators, in the modification of vocational education today and in its further development in the years ahead. This study is designed to discover the revisions and additions that are needed in the vocational curriculums of South Dakota, so that youth may be better prepared for employment. The response as reported by school administrators and teachers are appraised and compared as to the effectiveness of the vocational educations programs as they function in South Dakota

INCREASES IN COSTS AND RETURNS DUE TO INTENSIFYING RANGE FORAGE PRODUCTION SURVEYS: AN INFORMATION ECONOMIC ANALYSIS

The U.S. Congress and courts have directed federal natural resource agencies to use better information for management decisions than they have used in the past. It is also important for these agencies to improve the efficiency of resource use where possible. This information economics study estimates increased costs and revenues which can be directly imputed to improving the accuracy of range forage production surveys. It suggests that a high level of survey accuracy may often be justifiable.Crop Production/Industries, Research Methods/ Statistical Methods,

THE ECONOMICS OF ILLEGAL FISHING: A BEHAVIORAL MODEL

This paper analyzes the microeconomic behavior of fishers responding to imperfectly enforced regulations through illegal fishing and efforts to avoid detection. An intraseasonal optimization model is analyzed to determine optimal (profit-maximizing) harvesting strategies at the individual fisher level in response to input controls (such as gear or labor usage) or output controls (individual harvest quotas). For each regulatory option, the analysis explores: (a) the manner by which enforcement affects individual decisions concerning fishing and avoidance activity, (b) the level of enforcement necessary to achieve specified conservation goals, and (c) the role of various behavioral parameters in determining fisher decisions. It is shown, in particular, that the nature of avoidance behavior plays a crucial role in determining fisher response to regulations. Broad implications of illegal behavior on the sustainability of fishery systems are also discussed.Resource /Energy Economics and Policy,

Wave dispersion properties of compound finite elements

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Mixed finite elements use different approximation spaces for different dependent variables. Certain classes of mixed finite elements, called compatible finite elements, have been shown to exhibit a number of desirable properties for a numerical weather prediction model. In two-dimensions the lowest order element of the Raviart-Thomas based mixed element is the finite element equivalent of the widely used C-grid staggering, which is known to possess good wave dispersion properties, at least for quadrilateral grids. It has recently been proposed that building compound elements from a number of triangular Raviart-Thomas sub-elements, such that both the primal and (implied) dual grid are constructed from the same sub-elements, would allow greater flexibility in the use of different advection schemes along with the ability to build arbitrary polygonal elements. Although the wave dispersion properties of the triangular sub-elements are well understood, those of the compound elements are unknown. It would be useful to know how they compare with the non- compound elements and what properties of the triangular sub-grid elements are inherited? Here a numerical dispersion analysis is presented for the linear shallow water equations in two dimensions discretised using the lowest order compound Raviart-Thomas finite elements on regular quadrilateral and hexagonal grids. It is found that, in comparison with the well known C-grid scheme, the compound elements exhibit a more isotropic dispersion relation, with a small over estimation of the frequency for short waves compared with the relatively large underestimation for the C-grid. On a quadrilateral grid the compound elements are found to differ from the non- compound Raviart-Thomas quadrilateral elements even for uniform elements, exhibiting the influence of the underlying sub-elements. This is shown to lead to small improvements in the accuracy of the dispersion relation: the compound quadrilateral element is slightly better for gravity waves but slightly worse for inertial waves than the standard lowest order Raviart-Thomas element.The work of John Thuburn was funded by the Natural Environment Research Council under the 'Gung Ho' project (grant NE/1021136/1)