Toxic Hazards Research Unit

The activities of the Toxic Hazards Research Unit (THRU) for the period of June 1970 through May 1971 reviewed. Modification of the animal exposure facilities primarily for improved human safety but also for experimental integrity and continuity are discussed. Acute toxicity experiments were conducted on hydrogen fluoride (HF), hydrogen chloride (HCl), nitrogen dioxide (NO2), and hydrogen cyanide (HCN) both singly and in combination with carbon dioxide (CO). Additional acute toxicity experiments were conducted on oxygen difluoride (OF2) and chlorine pentafluoride (ClF5). Subacute toxicity studies were conducted on methylisobutylketone and dichloromethane (methylene dichloride). The interim results of further chronic toxicity experiments on monomethylhydrazine (MMH) are also described

The effects of iPads on the independent reading of high school students with learning disabilities

The purpose of this study was to determine whether or not the use of iPads for independent reading would enhance the reading motivation of ninth grade students with learning disabilities as measured by number of pages read and students\u27 self-reported interest in reading in response to a survey. Its purpose is also to determine whether they would prefer reading on an iPad over reading traditional books. This study used a pretest-posttest group design. The participants were nineteen students in ninth grade. The participants all receive special education services in the resource center classroom. They are enrolled in an intensive reading program called READ 180. The results indicate that more students read an increased number of pages on the iPad than of traditional books. However, the average number of pages read on an iPad was less than the average number of pages read of traditional books. Students completed a survey about their experience with reading on the iPad. Thirteen of the nineteen students agreed or strongly agreed that they prefer to read on the iPad compared to traditional books

Continuous animal exposure to dichloromethane

Continuous exposures of dogs, monkeys, rats and mice to 5000 ppm and 1000 ppm of dichloromethane vapor (CH2Cl2) produced severe toxic effects on dogs, rats and mice. Dogs died after 3 weeks exposure to 1000 ppm and after 6 weeks exposure to 5000 ppm. Thirty percent of the mice also succumbed during four weeks exposure to 5000 ppm CH2Cl2. Although rats survived 14 weeks exposure to 5000 ppm, they experienced subnormal weight gains. Significant gross and histopathological hepatic lesions were noted in all 3 species at death or experimental termination in 14 weeks. In addition, rats showed abnormal kidney histopathology. Fat stains disclosed mild fatty increase in monkey livers after 14 weeks exposure to 1000 ppm CH2Cl2

A study on the bioenergetics of a fresh water gastropod, planorbis planorbis l., in a small pond

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Effect of 90-day continuous exposure to methylisobutylketone on dogs, monkeys and rats

Continuous exposure of rats, dogs and monkeys to 410 mg/cu M methylisobutylketone vapor (MIBK) was conducted to evaluate the provisional spacecraft exposure limit of 20 ppm established by the Space Science Board in 1968. The exposure, conducted in a simulated space cabin environment, did not produce any measurable changes in dogs or monkeys. Rats developed hyaline droplet nephrosis within 2 weeks of exposure which was reversible upon removal from the MIBK even after 90 days. The data obtained indicated that the 60-minute emergency exposure limit of 100 ppm and the 90- and 1000-day provisional limits as established by the Space Science Board contain a wide margin of safety

Large diffractive/refractive apertures for space and airborne telescopes

Recent work, specifically the Lawrence Livermore National Laboratory (LLNL) Eyeglass and the DARPA MOIRE programs, have evaluated lightweight, easily packaged and deployed, diffractive/refractive membrane transmissive lenses as entrance apertures for large space and airborne telescopes. This presentation describes a new, innovative approach to the theory of diffractive and refractive effects in lenses used as telescope entrance apertures and the fabrication of the necessary large membrane optics. Analyses are presented to indicate how a broadband, highly transmissive diffractive / refractive membrane lens can be developed and fabricated, and potential applications in defense and astronomy are briefly discussed

“Born out of crisis”: assessing the legacy of the Exmoor moorland management agreements.

Copyright Cambridge University Press. Deposited following guidelines in SHERPA/RoMEO.Shortly after the designation of Exmoor National Park in 1954 the moorland that the park was charged with maintaining and enhancing came under threat from agricultural improvement. The ensuing ‘moorland conflict’ eventually lead to a pioneering system of moorland management agreements (MMAs). The MMAs have an important place in the transformation of agricultural policy and the development and social acceptance amongst farmers and landowners of the concept that farmers should be paid for their stewardship of the environment. Drawing on published and unpublished documents, as well as extensive interviews, this paper revisits the origins of the problem of moorland reclamation, assesses role played by key individuals in publicising the problem and promoting management agreements as a solution, considers the risks taken by those entering into management agreements, and identifies some of the tangible and intangible impacts of the MMA system