Polarized light scattering by aerosols in the marine atmospheric boundary layer

The intensity and polarization of light scattered from marine aerosols affect visibility and contrast in the marine atmospheric boundary layer (MABL). The polarization properties of scattered light in the MABL vary with size, refractive index, number distributions, and environmental conditions. Laboratory measurements were used to determine the characteristics and variability of the polarization of light scattered by aerosols similar to those in the MABL. Scattering from laboratory-generated sea-salt-containing (SSC) [NaCl, (NH4)2SO4, and seawater] components of marine aerosols was measured with a scanning polarization-modulated nephelometer. Mie theory with Gaussian and log normal size distributions of spheres was used to calculate the polarized light scattering from various aerosol composition models and from experimentally determined distributions of aerosols in the marine boundary layer. The modeling was verified by comparison with scattering from distilled water aerosols. The study suggests that polarimetric techniques can be used to enhance techniques for improving visibility and remote imaging for various aerosol types, Sun angles, and viewing conditions

An assessment of General Aviation utilization of advanced avionics technology

Needs of the general aviation industry for services and facilities which might be supplied by NASA were examined. In the data collection phase, twenty-one individuals from nine manufacturing companies in general aviation were interviewed against a carefully prepared meeting format. General aviation avionics manufacturers were credited with a high degree of technology transfer from the forcing industries such as television, automotive, and computers and a demonstrated ability to apply advanced technology such as large scale integration and microprocessors to avionics functions in an innovative and cost effective manner. The industry's traditional resistance to any unnecessary regimentation or standardization was confirmed. Industry's self sufficiency in applying advanced technology to avionics product development was amply demonstrated. NASA research capability could be supportive in areas of basic mechanics of turbulence in weather and alternative means for its sensing

Collisions with ice-volatile objects: Geological implications

The collision of the Earth with extra-terrestrial ice-volatile bodies is proposed as a mechanism to produce rapid changes in the geologic record. These bodies would be analogs of the ice satellites found for the Jovian planets and suspected for comets and certain low density bodies in the Asteroid belt. Five generic end-members are postulated: (1) water ice; (2) dry ice: carbon-carbon dioxide rich, (3) oceanic (chloride) ice; (4) sulfur-rich ice; (5) ammonia hydrate-rich ice; and (6) clathrate: methane-rich ice. Due to the volatile nature of these bodies, evidence for their impact with the Earth would be subtle and probably best reflected geochemically or in the fossil record. Actual boloids impacting the Earth may have a variable composition, generally some admixture with water ice. However for discussion purposes, only the effects of a dominant component will be treated. The general geological effects of such collisions, as a function of the dominant component would be: (1) rapid sea level rise unrelated to deglaciation, (2) decreased oceanic pH and rapid climatic warming or deglaciation; (3) increased paleosalinities; (4) increased acid rain; (5) increased oceanic pH and rapid carbonate deposition; and (6) rapid climatic warming or deglaciation

The Impact of Pensions on State Borrowing Costs

Municipal bond prices are tumbling and rates rising just as public borrowers face pressure to refinance deals cut during the financial crisis. At the same time, the funded status of public pension plans has declined, and states and localities will have to come up with more money to meet future benefit payments. In the private sector, numerous studies have shown that pension underfunding affects corporate bond ratings. And Moody’s just announced that it would combine unfunded pension liabilities with outstanding bonds when evaluating a state’s leverage position. These developments raise the question of how future pension commitments affect today’s borrowing costs in the public sector. The brief proceeds as follows. The first section describes the municipal bond market. The second section describes the factors that traditionally have been considered in the bond rating process. The third section summarizes what other researchers have found regarding the relationship between pension commitments and borrowing costs in the private and public sectors. The fourth section presents a model for the period 2005-2009 that relates borrowing costs to factors generally considered by the rating agencies, such as the state’s management, finances, economy, and debt structure. Pensions are a component of the debt structure, and the extent to which states make their Annual Required Contribution (ARC) has a statistically significant – albeit modest – impact on the cost of debt. A side finding is that the bond’s rating explains relatively little about the variation in interest cost, and the effect of pensions remains significant even including the bond’s rating in the equation. The final section concludes that while pension underfunding had only a small effect on borrowing costs in the 2005-2009 period when pension expenses were only 3 to 4 percent of state budgets, its impact could become more significant as the cost of pensions increases.

Pore fluid constraints on deep ocean temperature and salinity during the Last Glacial Maximum

Pore water records of δ^(18)O and [Cl] from ODP Site 1063A on the Bermuda Rise constrain the change in seawater δ^(18)O and salinity from the Last Glacial Maximum (LGM) to the Holocene to be 0.75±0.05‰ and 2.5±0.1% respectively. Coupled with a measured benthic foraminiferal δ^(18)O change, this result means that bottom waters were 4.6±0.8°C cooler than the Holocene at the LGM and therefore at or near the seawater freezing point. Coupled δ^(18)O and chlorinity results give an extrapolated mean ocean LGM to Holocene change in δ^(18)O of 0.95±0.09‰. These data also constrain the past southern source deep‐water salinity to be 35.76±0.04 psu, which is within error of the mean deep ocean value for this time

Dissolved Oxygen Conditions in the Machipongo River System near Willis Wharf, VA

Water temperature, salinity, and dissolved oxygen concentrations were monitored at two sites in the Machipongo River system in early summer of 1989 and late summer of 1990. The two study sites have been designated as Willis Wharf and Quinby. The Machipongo River system and the two sampling locations are shown in Figure 1

Multiparental mapping of plant height and flowering time QTL in partially isogenic sorghum families.

Sorghum varieties suitable for grain production at temperate latitudes show dwarfism and photoperiod insensitivity, both of which are controlled by a small number of loci with large effects. We studied the genetic control of plant height and flowering time in five sorghum families (A-E), each derived from a cross between a tropical line and a partially isogenic line carrying introgressions derived from a common, temperate-adapted donor. A total of 724 F2:3 lines were phenotyped in temperate and tropical environments for plant height and flowering time and scored at 9139 SNPs using genotyping-by-sequencing. Biparental mapping was compared with multiparental mapping in different subsets of families (AB, ABC, ABCD, and ABCDE) using both a GWAS approach, which fit each QTL as a single effect across all families, and using a joint linkage approach, which fit QTL effects as nested within families. GWAS using all families (ABCDE) performed best at the cloned Dw3 locus, whereas joint linkage using all families performed best at the cloned Ma1 locus. Both multiparental approaches yielded apparently synthetic associations due to genetic heterogeneity and were highly dependent on the subset of families used. Comparison of all mapping approaches suggests that a GA2-oxidase underlies Dw1, and that a mir172a gene underlies a Dw1-linked flowering time QTL

Dissolved oxygen measurements in the Machipongo River system near Willis Wharf, Virginia

Most aquatic organisms require· oxygen to survive and consequently, the dissolved oxygen (DO) content of the water is one of the most important measures of water quality. Sources of oxygen are the atmosphere and photosynthesis. Oxygen is consumed by plants and animals during respiration and by microorganisms that decompose organic matter. The more sources and sinks of oxygen, the more difficult it is to understand and predict the oxygen dynamics of a river system. Grossly polluted systems turn out to be quite simple, because the pollutant source dominates. Natural, unimpacted systems often show a balance between a number of sources and sinks and therefore are much more complex. The rivers of the Eastern Shore of Virginia typify this latter case. The Machipongo River, including its tributary Parting Creek, drains mostly agricultural land and forest. The river has extensive fringe marshes and tidal flats which are exposed at low water. A large mechanized clam processing facility located at Willis Wharf, Virginia also discharged wastewaters to Parting Creek. The organic loadings in these wastewaters have varied over time as processing techniques and production levels changed. Mathematical models are very useful tools that allow water quality managers to predict the environmental response to various actions, such as an increase in pollutant loads when a new facility begins discharging wastewaters or a decrease in pollutant loads when treatment levels are increased. Models can be only as good as the field data upon which they are based. When a system is complex, the data set must be comprehensive, and often extensive in time, so that there is sufficient information to allow the effects of all major factors to be determined. For the Machipongo River, such a field effort would be very expensive. Consequently, studies have been more limited in scope and designed to examine one factor only, namely the effects of the clam processing wastewaters. In the spring of 1989, a field study was undertaken to see if water quality differed between Parting Creek, which received the clam wastes, and the Machipongo River, which had no comparable wastewater loading. In the fall of 1990, another study was conducted to see whether conditions had changed in response to waste load reductions at the clam processing plant. Subsequently, the clam processing plant was closed, so the waste loading to Parting Creek was eliminated. This report describes the data collected during the spring of 1992, when there was no discharge from the plant. At a later date, these data will be compared with those from prior years to determine what, if any, change in water quality has resulted from the elimination of this point source of organic wastes