A Description of Summer Physical Oceanographic Conditions in Rupert Bay (James Bay, Canada)

Measurements of current velocity, temperature, salinity, and water level were made over a period of two months in Rupert Bay, James Bay (Canada). From an analysis of the current meter time series, the circulation and distribution of physical properties were found to be dominated by the tides, with the semi-diurnal component being the predominant component. An analysis of variance revealed that 77% of the salinity variations were related to the tides. Vertically homogeneous conditions prevailed in many areas because of a large tidal amplitude/depth ratio of 0.625, causing intense mixing in two-thirds of the estuary. Non-tidal velocity components were found to be 0(1) less than tidal currents, with the long-term mean circulation directed out of the bay. Non-tidal water level variations were well correlated with the wind. The maximum cross-correlation coefficient was calculated to be 0.77 for a 7 hour lag. The centrifugal force, Coriolis force, and baroclinic pressure gradient were dominant forces driving the secondary flows of the bay. Tidal fronts were found to be either aligned parallel to the main axes of principal channels or around small downstream islands with the arrangement influenced by bottom topography.Key words: estuary, circulation, tides, salinity, mixing, secondary flow, frontRÉSUMÉ. Des données de vitesse de courant, de température, de salinité et de niveau d’eau furent échantillonnées pendant une période de deux mois dans la Baie de Rupert, Baie James (Canada). Suite à l’analyse des séries chronologiques alors obtenues, il apperait que la circulation et la répartition des propriétés physiques étaient déterminées par les marées et que la constituante semi-diurne y dominait toute autre constituante de la marée. Une analyse de variance a révélé que 77% des variations de la salinité étaient attribuables aux marées semi-diurne. L’homogénéité de la colonne d’eau observée en plusieurs endroits semblait liée au fort rapport amplitude/profondeur (0,625) qui favoriserait un intense phénomène de mélange pour les deux tiers de l’estuaire. Les composantes de la vitesse étaient O(1) moins que les courants de marée. La circulation à long terme étaient dans la direction avale. Les variations de niveau d’eau non expliquées par la marée étaient apparemment induites par le vent; le coefficient de correlation croisée maximum calculé ont été de 0.77 pour un déphasage de 7 heures. Les fronts de marées observés soit étaient parallèles à les axes principaux des chenaux principaux ou suivaient le contour des petites îles sises en aval à l’entrée de la baie. L’arrangement de ces fronts semblait être influencé par la topographie du fond marin.Mot clés: estuaire, circulation, marées, salinité, mélange, courant secondaire, fron

Correlation between blister skin thickness, the maximum in the damage- energy distribution, and projected ranges of helium ions in Nb for the energy range 10 to 1500 keV

The skin thickness of blisters formed on polycrystalline niobium by $sup 4$He$sup +$ irradiation at room temperature for energies from 15 to 80 keV have been measured. Similar measurements were conducted for 10 keV $sup 4$He$sup +$ irradiation at 500$sup 0$C to increase blister exfoliation, and thereby allow examination of a larger number of blister skins. For energies smaller than 100 keV the skin thicknesses are compared with the projected range and the damage- energy distributions constructed from moments interpolated from Winterbon's tabulated values. For energies of 10 and 15 keV the projected ranges and damage- energy distributions have also been computed with a Monte Carlo program. For energies larger than 100 keV the projected ranges of $sup 4$He$sup +$ in Nb were calculated using either Brice's formalism or the one given by Schiott. The thicknesses for 60 and 80 keV, and those reported earlier for 100 to 1500 keV correlate well with calculated projected ranges. For energies lower than 60 keV the measured thicknesses are larger than the calculated ranges

Selection of monoploids for protoplast fusion and generation of intermonoploid somatic hybrids of potato

The original publication can be found at www.springerlink.comThe union of potato monoploid genotypes (2n=1x =12) through protoplast fusion may result in vigorous somatic hybrids due to a reduction of the genetic load normally present in this highly heterozygous tetraploid (2n=4x=48) crop. More than 100 androgenic monoploids derived from diploid (2n=2x=24) Solanum phureja Juz. & Buk. and S. chacoense Bitt. x S. phureja clones were evaluated in field trials during 1996 and 1997 to identify the most promising genotypes for protoplast fusion experiments. Compared to the total population, the 1996 selected genotypes had higher means for tuber number (30.1 vs 11.2 tubers/plant), average tuber weight (3.0 vs 1.8 g/tuber) and total yield (66.1 vs 20.4 g/plant). Similarly, the 1997 selected genotypes had higher means for tuber number (42.8 vs 25.4 tubers/plant), average tuber weight (3.6 vs 2.5 g/tuber) and total yield (114.0 vs 63.4 g/plant) compared to the total population. The 31 selected monoploid genotypes from 1996-97 varied in their response to protoplast isolation and culture from no growth (9), cell enlargement (5), limited cellular divisions (8), callus formation (5) to plant regeneration from callus (4). Chemical fusion and electrofusion produced three groups of intermonoploid somatic hybrids. Polymorphic simple sequence repeat (SSR) loci enabled distinction of somatic hybrids from parental somaclones. Rapid DNA extraction with SSR analysis enabled screening of calluses to identify somatic hybrid tissue prior to plant regeneration. The somatic hybrids were highly polyploid, mostly hexaploid (2n=6x=72), possibly due to fusion of endopolyploid protoplasts and/or chromosomal doubling during plant regeneration