A Portable Optical Planimeter for Measuring Leaf Area

Author Institution: Department of Botany, Ohio University, Athens, Ohi

Epigenetic regulation of crx and nrl binding to regulatory elements in the genomes of human retinal neurons

The retina is a neuronal tissue lining the back of the eye containing rod and cone photoreceptors that make vision possible. Highly regulated transcriptional networks control differentiation and maintenance of photoreceptors in the retina. DNA methylation of cytosine bases in genomic DNA is an epigenetic modification correlated with repression of gene expression. Currently in our lab, the biochemical relationship between DNA methylation and the ability of retina-specific transcription factors to bind in the genome is being studied. These transcription factors, known as cone-rod homeobox (CRX) and neural leucine zipper (NRL), have been shown to act synergistically to control photoreceptor expression in the retina. Preliminary data has supported the hypothesis that DNA methylation is critical for modulating cell-specific binding of CRX to target recognition sites. DNA binding domain coding sequences of the human CRX and NRL proteins were cloned into bacterial expression vectors, and were expressed and purified for downstream biochemical analysis. In vitro gel shift assays are currently being used to determine the ability of CRX and NRL to bind unmethylated and methylated oligonucleotides. Collectively, these studies will contribute to a better understanding of how epigenetic modifications influence the development, homeostasis and pathology of human retinal neurons

Ecological effects and environmental fate of solid rocket exhaust

Specific target processes were classified as to the chemical, chemical-physical, and biological reactions and toxic effects of solid rocket emissions within selected ecosystems at Kennedy Space Center. Exposure of Citris seedlings, English peas, and bush beans to SRM exhaust under laboratory conditions demonstrated reduced growth rates, but at very high concentrations. Field studies of natural plant populations in three diverse ecosystems failed to reveal any structural damage at the concentration levels tested. Background information on elemental composition of selected woody plants from two terrestrial ecosystems is reported. LD sub 50 for a native mouse (peromysous gossypinus) exposed to SRM exhaust was determined to be 50 ppm/g body weight. Results strongly indicate that other components of the SRM exhaust act synergically to enhance the toxic effects of HCl gas when inhaled. A brief summary is given regarding the work on SRM exhaust and its possible impact on hatchability of incubating bird eggs

Multipole methods for nanoantennas design: applications to Yagi-Uda configurations

International audienceWe present a detailed formalism allowing analytical calculations of the radiative properties of nanoantennas. This formalism does not rely on dipole approximations and utilizes multipolar multiple-scattering theory. The improvement in both accuracy and calculation speeds offered by this formulation provides significant advantages that are used in this work to study Yagi-Uda-type nanoantennas. We provide a study that questions the necessity of the reflector particle in nanoantennas

13-Historic Period Sites Recorded for the Kalamazoo River Basin, 1977-1981

During the five year Kalamazoo Basin Survey project (1976-1980), survey teams, under the direction of Dr. William M. Cremin of the Department of Anthropology, Western Michigan University, investigated by means of surface reconnaissance nine survey transects placed across the Kalamazoo River in Allegan, Kalamazoo, Calhoun and Jackson Counties, Michigan. Surveyor coverage in the nine transects aggregated 135 km 2 , or 18% of the land area delimited by their boundaries, and resulted in the recording of 328 prehistoric sites. In addition, interviews with area landowners and collectors ~aving knowledge of local prehistory and the whereabouts of archaeological sites resulted in the discovery of 24 sites located outside of the survey transects (Cremin 1981). Last year the WMU archaeological field school, under the direction of Dr. Cremin, traveled to western Jackson County to conduct limited test excavations at several sites located by KBS surveyors during the previous year and to expand upon the results of that program of research by undertaking some additional site location survey along the South Branch Kalamazoo River both within and outside of the boundaries established for KBS Transect l980C. On this occasion, surveyors evaluated about 2.1 km2 and recorded 24 more prehistoric sites occurring in western Jackson and eastern Calhoun Counties (Cremin and Clark 1981). In total, WMU\u27s program of systematic site location survey in this universe between 1976 and 1981 has resulted in the recovery of data representing 376 prehistoric sites in the four counties investigated. However, the various annual reports and the recently published overview of the Kalamazoo Basin Survey project do not reference a potentially important data set consisting of 47 sites that postdate Euro-American settlement of southern Lower Michigan and reflect in part the activities of both Euro-American and Native American residents of the Kalamazoo River Basin during the 19th and 20th centuries