The Current State of Solar Modeling

Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.     

Phyllosilicate diversity and past aqueous activity revealed at Mawrth Vallis, Mars

Observations by the Mars Reconnaissance Orbiter/Compact Reconnaissance Imaging Spectrometer for Mars in the Mawrth Vallis region show several phyllosilicate species, indicating a wide range of past aqueous activity. Iron/magnesium (Fe/Mg)-smectite is observed in light-toned outcrops that probably formed via aqueous alteration of basalt of the ancient cratered terrain. This unit is overlain by rocks rich in hydrated silica, montmorillonite, and kaolinite that may have formed via subsequent leaching of Fe and Mg through extended aqueous events or a change in aqueous chemistry. A spectral feature attributed to an Fe2+ phase is present in many locations in the Mawrth Vallis region at the transition from Fe/Mg-smectite to aluminum/silicon (Al/Si)-rich units. Fe2+-bearing materials in terrestrial sediments are typically associated with microorganisms or changes in pH or cations and could be explained here by hydrothermal activity. The stratigraphy of Fe/Mg-smectite overlain by a ferrous phase, hydrated silica, and then Al-phyllosilicates implies a complex aqueous history.     

Strange magnetism and the anapole structure of the proton

The violation of mirror symmetry in the weak force provides a powerful tool to study the internal structure of the proton. Experimental results have been obtained that address the role of strange quarks in generating nuclear magnetism. The measurement reported here provides an unambiguous constraint on strange quark contributions to the proton's magnetic moment through the electron-proton weak interaction. We also report evidence for the existence of a parity-violating electromagnetic effect known as the anapole moment of the proton. The proton's anapole moment is not yet well understood theoretically, but it could have important implications for precision weak interaction studies in atomic systems such as cesium.     

Field comparison of the interferon-gamma assay and the intradermal tuberculin test for the diagnosis of bovine tuberculosis

An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.     

Rose Gold: A yellow fleshed,pink-red skinned,tablestock cultivar with short dormancy and full season maturity

Rose Gold is a pink-red skinned, bright yellow fleshed, tablestock potato cultivar. In Ontario trials, Rose Gold is later maturing than its half sibling Red Gold and is characterized by producing larger and fewer tubers per plant than Red Gold. Rose Gold rarely develops symptoms of virus diseases when grown for repeated generations under high virus disease pressure (PVY, PLRV, PVX). Tubers have a very short dormancy. Yields are similar to Yukon Gold on mineral soil and generally higher than Red Gold. Rose Gold has produced high marketable yields on muck soil.     

Growth of early potatoes from different portions of seed tubers II. Yield

Several of the recently released early-potato (Solanum tuberosum L.) cultivars used in Ontario have produced uneven stands which have been shown to be a result of delayed emergence from basal end seed pieces. A study was conducted to evaluate the effects of seed portions on the yield of three early potato cultivars, Jemseg, Superior and Yukon Gold. Yield of plants from basal seed pieces was lower than that from apical seed pieces or whole tubers for Jemseg and Yukon Gold during several sequential harvests. With Superior, cut seed portions yielded less than whole seed. Number of stems per plant was lower for basal plants of Jemseg. Tubers with strong apical dominance or dormancy such as Jemseg and Yukon Gold are prone to differences in yield among seed portions.     

Growth of early potatoes from different portions of seed tubers I. Emergence and plant stand

Several of the recently released early potato cultivars in Ontario are prone to poor and/or uneven stands. Studies were undertaken to investigate these problems. Basal seed halves of Jemseg and Yukon Gold were found to emerge an average of 4.6 and 5.7 days, respectively, later than shoots from apical halves or whole tubers in 3 years of study. No practical difference in emergence was found among tuber portions of Superior. Sums of squares attributed to seed portions accounted for 51.1 percent of the variation of days to 50 percent emergence for Jemseg, 50.3% for Yukon Gold and 8 percent for Superior. No difference in final percent emergence was found among the various seed portions of Jemseg and Superior. Cultivars with strong apical dominance or dormancy appear prone to uneven emergence.