Best combiners during 40 years of breeding Vitis cuitivars resistant to Pierce's disease

By breeding for resistance to Pierce's disease in Vitis we have obtained useful cultivars that can be grown productively in areas formerly considered unsuitable for grape production. Reviewing the most successful recombinants from crosses made between 1945 and 1984, 6 Vitis clones were prominent foundation parents among those tested as primitive resistant germplasm: V. aestivalis, ssp. smalliana cvs Fla. 43-47 and Fla. 449, V. aestivalis ssp. simpsoni cvs Pixiola and Fla. 451, and V. shuttleworthii cvs Haines City and Kissimmee. The best combiners for productivity, fruit size, and high quality were PD susceptible cultivars Aurelia, Carolina Blackrose, Cardinal, Exotic, Golden Muscat, and Villard blanc. The best combiners for seedlessness and early ripening were susceptible cultivars Lakemont and Perlette. Selection for resistance to PD required 7 or more years each generation for exposure of seedlings to PD-carrying vectors. Inbreeding was detrimental to vine vigor but good combiners were selected among inbred progeny which were more homozygous for disease resistance. Subsequent crosses of these inbreds to large-fruited, high-quality cultivars resulted in some recombinants with restored vigor and superior traits such as Blanc Du Bois

Low-loss criterion and effective area considerations for photonic crystal fibers

We study the class of endlessly single-mode all-silica photonic crystal fibers with a triangular air-hole cladding. We consider the sensibility to longitudinal nonuniformities and the consequences and limitations for realizing low-loss large-mode area photonic crystal fibers. We also discuss the dominating scattering mechanism and experimentally we confirm that both macro and micro-bending can be the limiting factor.Comment: Accepted for Journal of Optics A - Pure and Applied Optic

Levitated droplet dye laser

We present the first observation, to our knowledge, of lasing from a levitated, dye droplet. The levitated droplets are created by computer controlled pico-liter dispensing into one of the nodes of a standing ultrasonic wave (100 kHz), where the droplet is trapped. The free hanging droplet forms a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating spectrometer. With this setup we have achieved reproducible lasing spectra in the visible wavelength range from 610 nm to 650 nm. The levitated droplet technique has previously successfully been applied for a variety of bio-analytical applications at single cell level. In combination with the lasing droplets, the capability of this high precision setup has potential applications within highly sensitive intra-cavity absorbance detection.Comment: 6 pages including 3 figure

Direct measurement of drainage curves in infiltration of SiC particle preforms: influence of interfacial reactivity

We present dynamic measurement of drainage curves in two systems having relevance to metal matrix composite processing, namely SiC/Al and SiC/Al-12.2at%Si. Data show that liquid/solid chemical reactions that cause a lowering of the contact angle do indeed drive spontaneous ingress of metal into the preforms at fixed applied pressure; however, these also hinder infiltration under continuous infiltration, lower pressurization rates causing a reduced level of penetration by the metal at given pressure. Metal/reinforcement chemical interactions that can drive wetting by lowering the contact angle are, therefore, not necessarily beneficial in the pressure infiltration processing of particle reinforced metal

Wetting in infiltration of alumina particle preforms with molten copper

The high-temperature wettability of alumina particulate preforms by copper is investigated by means of infiltration experiments conducted at 1473 K under low oxygen partial pressure. Wetting is quantified in terms of drainage curves, which plot the volume fraction of metal in the porous medium vs. the applied pressure. Mercury porosimetry is also used on similar preforms for comparison. The effect of volume fraction, particle geometry and capillary parameters on the drainage curve are studied and compared with the expression proposed by Brooks and Corey. The influence of the particle volume fraction and capillary parameters characterizing wetting in the two systems is discussed to derive an effective contact angle for wetting of alumina particles by molten coppe

Strontium Exchange Characteristics of Soils from the Ogotoruk Creek Watershed in Alaska

Author Institution: Department of Agronomy, Ohio Agricultural Experiment Station, and The Ohio State University, Columbus 1

Leisure activity associated with cognitive ability level, but not cognitive change

Although activity participation is promoted as cognitively-protective, critical questions of causality remain. In a cohort followed every five years from age 75 to 85 years, potential reciprocal associations between level and change in leisure activity participation and level and change in cognitive abilities were examined. Participants in the Glostrup 1914 Cohort, a longitudinal study of ageing, completed standardised cognitive ability tests and reported their leisure activity participation (11 activities defined a leisure activity score) at ages 75, 80 and 85. Higher leisure activity was associated with higher cognitive ability (significant correlations ranged from .15 to .31, p < .05). Between ages 75 and 85, participation in leisure activities and cognitive ability declined significantly. Growth curve models, which provided latent variables for level of and 10-year change in both leisure activity and cognitive ability, confirmed the positive association between levels of leisure activity and cognitive ability (path coefficient = .36, p < .001); however, leisure activity level or change was not associated with cognitive change. Although a positive association between leisure activity and cognitive ability was reported—the likely precedents of this are discussed—there was no evidence that a higher level or maintenance of leisure activity was protective against cognitive decline across a 10-year follow-up