Winter ozone formation and VOC incremental reactivities in the Upper Green River Basin of Wyoming

The Upper Green River Basin (UGRB) in Wyoming experiences ozone episodes in the winter when the air is relatively stagnant and the ground is covered by snow. A modeling study was carried out to assess relative contributions of oxides of nitrogen (NO_x) and individual volatile organic compounds (VOCs), and nitrous acid (HONO) in winter ozone formation episodes in this region. The conditions of two ozone episodes, one in February 2008 and one in March 2011, were represented using a simplified box model with all pollutants present initially, but with the detailed SAPRC-07 chemical mechanism adapted for the temperature and radiation conditions arising from the high surface albedo of the snow that was present. Sensitivity calculations were conducted to assess effects of varying HONO inputs, ambient VOC speciation, and changing treatments of temperature and lighting conditions. The locations modeled were found to be quite different in VOC speciation and sensitivities to VOC and NO_x emissions, with one site modeled for the 2008 episode being highly NO_x-sensitive and insensitive to VOCs and HONO, and the other 2008 site and both 2011 sites being very sensitive to changes in VOC and HONO inputs. Incremental reactivity scales calculated for VOC-sensitive conditions in the UGRB predict far lower relative contributions of alkanes to ozone formation than in the traditional urban-based MIR scale and that the major contributors to ozone formation were the alkenes and the aromatics, despite their relatively small mass contributions. The reactivity scales are affected by the variable ambient VOC speciation and uncertainties in ambient HONO levels. These box model calculations are useful for indicating general sensitivities and reactivity characteristics of these winter UGRB episodes, but fully three-dimensional models will be required to assess ozone abatement strategies in the UGRB

LABOR STRIKES AND THE PRICE OF LETTUCE

This paper examines the economic impact of the 1979 labor strike against lettuce producer-shippers in the Imperial Valley of California. The theory presented suggests that formidable problems are encountered by agricultural labor unions in obtaining higher wages for farm workers. During the 1979 strike, ironically the returns to many of the lettuce producers in the Imperial Valley increased substantially.Demand and Price Analysis, Labor and Human Capital,

Earth Flows Along Henry Creek, Northern Alaska

Many earth flows occurred during the summer of 1979 in the hilly terrain near Umiat, Alaska, particularly along Henry Creek. Most were shallow, involving only the tundra mat and no more than 1.5 m of the underlying mud. The summer of 1979 was the warmest and wettest for the period of record at Umiat, and precipitation was characterized by brief but intense localized rainstorms. Failure probably was triggered by the heavy rains and facilitated by an absorbent tundra mat over a clayey substrate, and perhaps in some cases by a thicker than normal active layer. Flows of this kind have occurred repeatedly in the Uniat area, most likely during summers in which climatic conditions were similar to those of 1979.Key words: earth flows, rainfall, temperature, active layer, bentonitic materials, Alask

Simple Calculations to Reduce Litigation Costs in Personal Injury Cases: Additional Empirical Support for the Offset Rule

This article demonstrates that if the nominal rate of interest equals the growth rate of nominal earnings, then a strong case can be made for calculating lump-sum damage awards by using the offset rule, i.e., by simply multiplying the annual loss by the number of years the loss is expected to continue. An examination of the Canadian data not only supports the offset rule, but also suggests that plaintiffs are being systematically undercompensated by rules currently in use

Limnological, Ichthyological, and Parasitological Investigations on Arkansas Reservoris in Relation to Water Quality

Lake Fort Smith, a 525 acre (212 ha) reservoir, was impounded in 1936 as a water supply for the city of Fort Smith. The reservoir is located on Clear Creek (Frog Bayou), a tributary of the Arkansas River, in the Boston Mountains 28 miles (45 km) northeast of the city of Fort Smith in Crawford County, Arkansas. A map and morphometric characteristics of Lake Fort Smith are given in Fig. 1 and Table I (Hoffman, 1951; Nelson, 1952). In 1956 Lake Shepherd Springs, a 750 acre (304 ha) impoundment, was created one mile upstream of Lake Fort Smith (Rorie, 1961). Both lakes have a shale substrate and are subject to periods of high turbidity. The 2 two lakes have a water shed of 65 square mile area (168 km ) of mountainous oak-hickory forest. Lake Shepherd Springs has not acted as a settling basin for sediments; thus, the upper portion of Lake Fort Smith has numerous shallow areas with a mud bottom supporting various submergent and emergent aquatic plants. The lower portion of the lake has a rocky, shale substrate with only limited emergent vegetation

YIG Oscillators: Is a Planar Geometry Better?

Two yttrium-iron-garnet (YIG) oscillator technologies are comparerk the more mature YIG sphere oscillator technology which is based on the uniform (resonant) precession of the electron spins in a smafl sphere of YIG, and the new planar YIG technology which utilizes the propagation of magnetostatic waves in an epitaxiaf film of YIG. The YIG sphere technology has been used for microwave oscillators for more than 25 years, but has two significant areas of difficulty in applications the alignment of the YIG sphere in the magnetic bias field coupfbrg cavity requires great precision and the gain element requires a negative resistance element to sustain oscillation. The MSW technology is much newer and less well understood, but the resonator elements are fabricated using a 50- pm line width planar technology making it assappealhg candidate. Both technologies are reviewed herein with regard to resonant element theory, temperature, and noise characteristics. New data and theory are presented on MSW resonator optimization

GRTS and Graphs: Monitoring Natural Resources in Urban Landscapes

Environmental monitoring programs are an important tool for providing land managers with a scientific basis for management decisions. However, many ecological processes operate on spatial scales that transcend management boundaries (Schonewald-Cox 1988). For example, adjacent lands may influence protected-area resources via edge effects, source-sink dynamics, or invasion processes (Jones et al. 2009). Hydrologic alterations outside management units also may have profound effects on the integrity of resources being managed (Pringle 2000). The impacts of climate change are presenting challenges to resource management at local-to-global scales (Karl et al. 2009). This potential disparity between ecological and political boundaries presents an interesting dilemma for natural resource monitoring and is readily apparent in urban and agricultural environments, which tend to be dominated by external stressors (Collins et al. 2000). Despite their limited control over external land use, natural resource managers are concerned with processes such as development in the surrounding landscape, as these may lead to habitat loss and degradation that directly impair their resources. As a consequence, the management of the natural resources in and around parks and other areas requires a broad and dynamic understanding of the spatio-temporal patterns of environmental change. If monitoring is to be successful in providing data that inform management, information about regional and landscape context should play a critical role in designing monitoring strategies

A Teacher’s Checklist for Evaluating Treatment Intrusiveness

Teachers are frequently involved in developing and evaluating treatments for problematic behaviors. Along with other members of the interdisciplinary team, they must determine the level of intrusiveness that a treatment may have on a student. Several factors that influence the intrusiveness of treatment procedures are described. These factors were used to develop a checklist that could be used systematically by teachers to evaluate the intrusiveness of treatments recommended by treatment teams. After the checklist was administered to a group of preservice teachers, it was found to be capable of discriminating among several treatment options described in a series of case vignettes. The implications of incorporating such a checklist into the design and implementation of treatments for problem behavior are discussed.Les enseignants sont souvent impliqués dans le développement et l’évaluation de traitements des problèmes de comportement. De concert avec d’autres membres d’une équipe interdisciplinaire, ils doivent déterminer dans quelle mesure un traitement est intrusif pour l’élève. L’article décrit plusieurs facteurs qui influencent le degré de discrétion des procédures. À partir de ces facteurs, on a dressé une liste de vérification dont pourraient se servir les enseignants de façon systématique pour évaluer à quel point les procédures recommandées par les équipes de traitement sont intrusives. La liste a été présentée à un groupe de stagiaires et s’est avérée capable de distinguer plusieurs options de traitement décrites dans une série de vignettes d’étude de cas. S’ensuit une discussion portant sur les conséquences d’incorporer une telle liste de vérification dans la conception et la mise en œuvre de traitements pour les problèmes de comportement