Tropospheric sulfate distribution during SUCCESS: Contributions from jet exhaust and surface sources

The distribution of SO4= aerosol over the central US during SUCCESS indicates that surface sources of SO4= and SO2 in the western US caused SO4= enhancements up to 10 km altitude. The mean (median) SO4= mixing ratio in the mid- and upper-troposphere increased from 24 (16) pptv over the Pacific ocean to 58 (29) pptv over the central plains. Above 10 km the SO4=mixing ratio was essentially the same in both regions, and also when the geographic classifications were further partitioned into upper tropospheric and lower stratospheric categories (mean near 40 pptv). No obvious enhancements of SO4= could be detected in jet exhaust plumes, but this may reflect the difficulty of keeping a large airborne sampling platform within a turbulent wake for time periods longer than a few seconds. Expected SO4=enhancements (based on observed CO2 enhancements and emission factors for these two species) were generally much smaller than the variability of ambient SO4= mixing ratios, so our null result does not mean that aircraft do not emit H2SO4

Influence of vertical transport on free tropospheric aerosols over the central USA in springtime

Measurements of the atmospheric aerosol chemical composition during the Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) indicate substantial vertical transport of boundary layer aerosol to the free troposphere over the south-central United States during springtime. Mixing ratios of water-soluble aerosol Ca 2+ at 6 - 12 km altitude exhibited a median mixing ratio of 20 pptv, with 15% of the measurements \u3e 100 pptv and a maximum of ! 235 pptv. In air parcels with enhanced Ca 2+, the ratios K+/Ca 2+, Mg2+/Ca 2+, and Na+/Ca 2+ in the bulk aerosol were distinctly characteristic of those in limestone and/or cement. Significantly enhanced mixing ratios of aerosol SO42-, NO3-, and NH4 + were also concomitant with the elevated Ca 2+, suggesting transport of both crustal and anthropogenic aerosols to the upper troposphere. The mass concentration of water-soluble aerosol material was in the range 0.1 - 6 pg m -3 STP, and estimated crustal dust levels were 7 - 160 pg m \u273 ST

Mechanism of Protein Synthesis

Animal muscle proteins are stated by Rose (10) to contain 21 amino acids of which 10 must be derived directly from the food while 11 can be modified by transamination provided some other primary amino acid is supplied. Although storage and particularly seed proteins are relatively simple in their structural pattern and amino acid content, herbivorous, and eventually all, animals derive their amino acids entirely from plant products. It seems reasonable to assume, therefore, that leaf proteins are comparable in complexity and amino acid distribution to muscle proteins

Effects of Over Liming an Iowa Soil with Gypsum (Abstract)

A sample of Clarion loam soil taken near the U. S. Gypsum Co. plant at Fort Dodge, for which the owner claimed accumulated injury from dust deposits, showed no symptoms of high -Ca injury. Potted crop plants growing in the soil showed marked response to nitrogen and phosphorus added together, little or no response to potassium added alone to balance excess calcium ions, and responded positively to additional applications of gypsum at the rate of 100,000 pounds an acre

TESTING FOR DIFFERENTIAL EFFECTS OF FOREST FIRES ON HIKING AND MOUNTAIN BIKING DEMAND AND BENEFITS

Surveys of visitors to National Forests in Colorado were conducted to determine whether different fire ages and presence of crown fires have different effects on hiking and mountain biking recreation visits and benefits. Actual and intended behavior data were combined using a count-data travel cost model. The intended behavior trip questions asked about changes in number of trips due to the presence of a high-intensity crown fire, prescribed fire, and a 20-year-old high-intensity fire at the area respondents were visiting. Using the estimated recreation demand function, years since a non-crown fire had statistically significant positive effect on the trip demand of hikers. In contrast, presence of crown fires had no statistically significant effect on the quantity of hiker trips, but had a significant and negative effect on mountain biking trips. Crown fires also had a large effect on the value per trip, with crown fires increasing the value per hiking trip but lowering the value per mountain biking trip.Resource /Energy Economics and Policy,

Tests of Ocean-Tide Models by Analysis of Satellite-To-Satellite Range Measurements: An Update

Seven years of GRACE intersatellite range-rate measurements are used to test the new ocean tide model FES2014 and to compare against similar results obtained with earlier models. These qualitative assessments show that FES2014 represents a marked improvement in accuracy over its earlier incarnation, FES2012, with especially notable improvements in the Arctic Ocean for constituents K(sub 1) and S(sub 2). Degradation appears to have occurred in two anomalous regions: the Ross Sea for the O(sub 1) constituent and the Weddell Sea for M(sub 2)

The Effect of Wind on Transpiration and Evaporation Through Multiperforate Septa

Diffusion of water vapor through single-pore membranes with pores 100 to 800 μ in diameter and multipore membranes with pores 2.5 to 20 μ in diameter was studied as a function of wind velocity. The results of these studies are compared with data obtained with transpiring leaves in wind. It was found that wind had relatively little effect on small pores as compared with large pores and free water surfaces. The primary response of stomates or small, isolated pores to wind was simply an increase in the diffusion gradient. In general, the wind-to-still-air diffusion ratios determined with the use of small pores, either isolated or as a part of a multipore system, were less than 2, while the ratio for open surface evaporation in 1,000 feet per minute wind exceeded 15. The relatively small response of transpiration to wind is tenable, considering the epidermis as a multiperforate septum