Chloride accumulation in different species of grapevine

A range of self-rooted vines, many of which have been used as nematode- and phylloxera-resistant rootstocks, were surveyed for chloride concentration. Petiole analysis showed the following trend for chloride accumulation among Vitis species: V. rupestris < V. berlandieri, V. riparia < V. candicans, V. champini, V. longii < V. cineria, V. cordifolia < V. vinifera.     

Influence of temperature,soil moisture and CCC on the flowering of Euphorbia fulgens

In the short-day plant Euphorbia fulgens under short-day conditions the flower induction in the shoot apex is delayed more and more nodes are formed beneath the final cyathium, the higher the temperature up to 28°C. The delay of induction is greater with plants growing in a moist soil than in a dry soil. The difference between moist and dry soil is greater, the higher the temperature. There are slight temporal differences in the induction of the lateral shoots in the temperature range between 15°C and 25°C, but the number of nodes formed at the lower paracladia is greater at the higher temperature. The development of the cyathia is enhanced at high temperatures. At temperatures above 28°C induction is prevented. The temperature limit for induction is some degrees higher for plants in dry soil than for those in moist soil. Cycocel causes effects similar to those caused by water deficiency, although the newly formed internodes become shorter.     

Thermal Structure and Energy Influx to the Day-and Nightside Venus Ionosphere

Pioneer Venus in situ measurements made with the retarding potential analyzer reveal strong variations in the nightside ionospheric plasma density from location to location in some orbits and from orbit to orbit. The ionopause is evident at night as a relatively abrupt decrease in the thermal plasma concentration from a few hundred to ten or fewer ions per cubic centimeter. The nightside ion and electron temperatures above an altitude of 250 kilometers, within the ionosphere and away from the terminator, are comparable in magnitude and have a value at the ionopause of approximately 8000 K. The electron temperature increases from a few tens of thousands of degrees Kelvin just outside the ionopause to several hundreds of thoussands of degrees Kelvin further into the shocked solar wind. The coldest ion temperatures measured at an altitude of about 145 kilometers are 140 to 150 K and are still evidently above the neutral temperature. Preliminary day-and nightside model ion and electron temperature height profiles are compared with measured profiles. To raise the model ion temperature to the measured ion temperature on both day-and nightsides, it was necessary to include an ion energy source of the order of 4 x 10(-3) erg per square centimeter per second, presumably Joule heating. The heat flux through the electron gas from the solar wind into the neutral atmosphere averaged over day and night may be as large as 0.05 erg per square centimeter per second. Integrated over the planet surface, this heat flux represents one-tenth of the solar wind energy expended in drag on the sunward ionopause hemisphere.     

Changing role of public and private sectors in agricultural research

The considerations involved in defining appropriate roles for the public and private sectors in agricultural research are examined with respect to mechanization, plant variety, and insecticide research and development. It is concluded that the public sector should continue to give mechanization a low priority. Varietal improvement should remain a relatively high priority until the effects of plant variety protection legislation become more apparent. Simultaneous achievement of safety, environmental, and productivity objectives in insect pest control will require that the public sector play a larger role in research and development.     

Japanese supercomputer technology

Under the auspices of the Ministry for International Trade and Industry the Japanese have launched a National Superspeed Computer Project intended to produce high-performance computers for scientific computation and a Fifth-Generation Computer Project intended to incorporate and exploit concepts of artificial intelligence. If these projects are successful, which appears likely, advanced economic and military research in the United States may become dependent on access to supercomputers of foreign manufacture.     

Avian and Mammalian mitochondrial ammonia-detoxifying systems in tortoise liver

Liver mitochondria from the desert tortoise Gopherus agassizii and the Texas tortoise G. berlandieri contain glutamine synthetase, the enzyme used by birds and higher reptiles to detoxify ammonia generated intramitochondrially during amino acid catabolism. Tortoise mitochondria also contain carbamyl phosphate synthetase-I and ornithine transcarbamylase, the enzymes used by mammals for this purpose. Since chelonid reptiles have changed little since their divergence from the stem reptiles, this finding suggests that both systems were present in the latter before the emergence of the ruling reptile, avian, and mammalian lines of descent.     

Chlorine monoxide radical, ozone, and hydrogen peroxide: stratospheric measurements by microwave limb sounding

Profiles of stratospheric ozone and chlorine monoxide radical (C1O) have been obtained from balloon measurements of atmospheric limb thermal emission at millimeter wavelengths. The C1O measurements, important for assessing the predicted depletion of stratospheric ozone by chlorine from industrial sources, are in close agreement with present theory, The predicted decrease of C1O at sunset was measured. A tentative value for the stratospheric abundance of hydrogen peroxide was also determined.     

Observation of superflow in solid helium

We report on the observation of nonclassical rotational inertia in solid helium-4 confined to an annular channel in a sample cell under torsional motion, demonstrating superfluid behavior. The effect shows up as a drop in the resonant oscillation period as the sample cell is cooled below 230 millikelvin. Measurement of 17 solid samples allows us to map out the boundary of this superfluid-like solid or supersolid phase from the melting line up to 66 bars. This experiment indicates that superfluid behavior is found in all three phases of matter.     

A zinc clasp structure tethers Lck to T cell coreceptors CD4 and CD8

The T cell coreceptors CD4 and CD8 both associate via their cytoplasmic tails with the N-terminus of the Src-family tyrosine kinase Lck. These interactions require zinc and are critical for T cell development and activation. We examined the folding and solution structures of ternary CD4-Lck-Zn2+ and CD8alpha-Lck-Zn2+ complexes. The coreceptor tails and the Lck N-terminus are unstructured in isolation but assemble in the presence of zinc to form compactly folded heterodimeric domains. The cofolded complexes have similar "zinc clasp" cores that are augmented by distinct structural elements. A dileucine motif required for clathrin-mediated endocytosis of CD4 is masked by Lck.