Application of ERTS-1 Imagery to Flood Inundation Mapping

Application of ERTS-1 imagery to flood inundation mapping in East and West Nishnabotna basins of southwestern Iow

Evaluation of macrophyte control in 38 Florida lakes using triploid grass carp

Florida’s large number of shallow lakes, warm climate and long growing season have contributed to the development of excessive growths of aquatic macrophytes that have seriously interfered with many water use activities. The introduction of exotic aquatic macrophyte species such as hydrilla ( Hydrilla verticillata ) have added significantly to aquatic plant problems in Florida lakes. The use of grass carp ( Ctenopharyngodon idella ) can be an effective and economical control for aquatic vegetation such as hydrilla. Early stocking rates (24 to 74 grass carp per hectare of lake area) resulted in grass carp consumption rates that vastly exceeded the growth rates of the aquatic plants and often resulted in the total loss of all submersed vegetation. This study looked at 38 Florida lakes that had been stocked with grass carp for 3 to 10 years with stocking rates ranging from < 1 to 59 grass carp per hectare of lake and 1 to 207 grass carp per hectare of vegetation to determine the long term effects of grass carp on aquatic macrophyte communities. The median PAC (percent area coverage) value of aquatic macrophytes for the study lakes after they were stocked with grass carp was 14% and the median PVI (percent volume infested) value of aquatic macrophytes was 2%. Only lakes stocked with less than 25 to 30 fish per hectare of vegetation tended to have higher than median PAC and PVI values. When grass carp are stocked at levels of > 25 to 30 fish per hectare of vegetation the complete control of aquatic vegetation can be achieved, with the exception of a few species of plants that grass carp have extreme difficulty consuming. If the management goal for a lake is to control some of the problem aquatic plants while maintaining a small population of predominately unpalatable aquatic plants, grass carp can be stocked at approximately 25 to 30 fish per hectare of vegetation

Education for worker management and ownership of an inner-city enterprise.

Inner-city economic development as well as educational reform is essential for empowering poor urban residents to compete in the economy and polity. Increasingly, the notion of local control over economic development, and education to that end, has arisen as a critical concern among theoreticians and practitioners. A model that inextricably entertwines economic control with education is worker-controlled and -owned enterprise. Such enterprises can provide jobs and income for often-unemployed urban residents who have been particularly hard-hit by economic restructuring, recession, and racism. Within such enterprises, poor and low-skilled workers are challenged by and imparted dignity through participation in policy decision-making and work design. A focus on economic development moves the civil rights agenda of the 1960\u27s and \u2770\u27s to confrontation with contemporary economic and racial realities, while collective (albeit private) control of enterprise challenges conservative, traditional approaches to community economic development. A highly successful home-health care enterprise in New York City which has created a substantial number of high-quality, low-skilled jobs for inner-city residents utilizing the worker-controlled and -owned model was studied. A case-study approach to determine the historical sequence of events was employed. A qualitative methodology involving interviews with individual workers and managers as well as statistically-compiled responses from virtually all workers to determine worker participation and satisfaction was utilized. The enterprise was compared with other traditionally-structured New York City home health care agencies as well as with another worker-controlled and -owned enterprise which was not a home health care agency. The study concluded that the worker-controlled and -owned model can be effective in addressing both urban poverty and poor education. Six essential elements for achieving democratic urban economic development are: (1) job creation; (2) service to local low-to-moderate income constituency; (3) design of challenging, full-time, tenured work; (4) democratization of workplace decision-making and profit; (5) payment of reasonable wages and benefits; and (6) contribution to further community economic development. The model studied introduced worker-ownership only after the enterprise had stabilized out of consideration for poor workers\u27 financial limitations as well as a need for managerial control in establishing a viable enterprise. A nonformal educational method proved highly effective with low-skilled workers

Nutrient Limitation of Periphyton in a Spring-Fed, Coastal Stream in Florida, USA.

There is strong evidence to suggest that ground-water nitrate concentrations have increased in recent years and further increases are expected along portions of the central Gulf coast of Florida. Much of the nitrate enriched groundwater is discharged into surface waters through numerous freshwater springs that are characteristic of the area and the potential for eutrophication of their receiving waters is a legitimate concern. To test the potential effects of elevated nutrient concentrations on the periphyton community an in situ nutrient addition experiment was conducted in the spring-fed Chassahowitzka River, FL, USA, during the summer of 1999. Plastic tubes housing arrays of glass microscope slides were suspended in the stream. Periphyton colonizing the microscope slides was subjected to artificial increases in nitrogen, phosphorus or a combination of both. Slides from each tube were collected at 3- to 4- day intervals and the periphyton communities were measured for chlorophyll concentration. The addition of approximately 10 μg/L of phosphate above ambient concentrations significantly increased the amount of periphyton on artificial substrates relative to controls; the addition of approximately 100 μg/L of nitrate above ambient concentrations did not. The findings from this experiment implicated phosphorus, rather than nitrogen, as the nutrient that potentially limits periphyton growth in this system.(PDF contains 4 pages.

Homiletics

Homiletics

Homiletics

Homiletics: The Pericopic Lectionar

Photoluminescence and Terahertz Emission from Femtosecond Laser-Induced Plasma Channels

Luminescence as a mechanism for terahertz emission from femtosecond laser-induced plasmas is studied. By using a fully microscopic theory, Coulomb scattering between electrons and ions is shown to lead to luminescence even for a spatially homogeneous plasma. The spectral features introduced by the rod geometry of laser-induced plasma channels in air are discussed on the basis of a generalized mode-function analysis.Comment: 4 pages with 2 figures