The effect of right-turn-on-red on pedestrian and bicyclist accidents

Right-Turn-on-Red (RTOR), in its “Western” version allows motorists to turn right on a red signal after stopping and yielding, unless specifically prohibited by a sign. The objective of this study was to determine the effect of Western RTOR on pedestrian and bicycle accidents in selected jurisdictions adopting the rule in the mid-1970s. The results showed significant increases in pedestrian and bicyclist accidents involving right-turning vehicles at signalized locations following the introduction of Western RTOR. These increases were: 40 % for pedestrians and 82 % for bicycles in New York State; 107 % for pedestrians and 72 % for bicycles in Wisconsin; 57 % for pedestrians and 80 % for bicycles in Ohio; and 82 % for pedestrians in New Orleans. Analysis of police accident reports suggested that drivers stopped for a red light are looking left for a gap in traffic and do not see pedestrians and bicyclists coming from their right. Countermeasure research and development was recommended to deal with this well defined problem which involves between 1 % and 3 % of all pedestrian and bicycle accidents.     

Slash fire hazard analysis on the Siskiyou National Forest

Potential increase in fire hazard as a result of timber harvesting is a concern of forest managers throughout the United States. Treating fuels can help reduce unacceptable fire hazards. To evaluate alternative fuel treatments, managers need to know their effects on fire hazard. A decision analysis approach to estimating fire hazard in terms of expected burned area was applied to a watershed in the Siskiyou National Forest (Oregon). Three treatment alternatives (do nothing and two levels of yarding unmerchantable material) were evaluated, and the effects of the treatments were projected over a 90-yr period. Initially, the effects of applying a treatment are small. After 50 years of treatment, the most intense alternative can be expected to show almost a 50% reduction in burned area compared to no treatment. The procedure also estimates burned are by fire size and fire intensity classes. Managers may find this useful for estimating expected fire effects associated with a particular fuel treatment regime.     

EFFECTS OF URBANIZATION ON BASE FLOW OF SELECTED SOUTH-SHORE STREAMS,LONG ISLAND,NEW YORK1

ABSTRACT: Hydrograph analysis of six streams on the south shore of Long Island indicates that eastward urbanization during the last three decades has significantly reduced base flow to streams. Before urbanization, roughly 95 percent of total annual stream flow on Long Island was base flow. In urbanized southwestern Nassau County, storm water sewerage, increased impervious surface area, and sanitary sewerage have reduced base flow to 20 percent of total stream flow. In an adjacent urbanized but unsewered area in southeastern Nassau County, base flow has decreased to 84 percent of total annual stream flow. In contrast, base flow in two streams in rural areas has remained virtually constant, averaging roughly 95 percent of total annual flow throughout the 1955-70 study period. Double-mass curve analysis of base flow as a percentage of total annual stream flow indicates that (1) changes in stream flow characteristics began in the early 1960's in the sewered area and in the late 1960's in the later urbanized, unsewered area, and (2) a new equilibrium has been established between the streams in the sewered area and the new hydrologic characteristics of their urbanized drainage basins.     

THE EFFECT OF DATA INDEPENDENCE IN MODEL CALIBRATION AND MODEL TESTING1

ABSTRACT: With the increased use of models in hydrologic design, there is an immediate need for a comprehensive comparison of hydrologic models, especially those intended for use at ungaged locations (i.e., where measured data are either not available or inadequate for model calibration). But some past comparisons of hydrologic models have used the same data base for both calibration and testing of the different models or implied that the results of model calibration are indicative of the accuracy at ungaged locations. This practice was examined using both the regression equation approach to peak discharge estimation and a unit hydrograph model that was intended for use in urban areas. The results suggested that the lack of data independence in the calibration and testing of regression equations may lead to both biased results and misleading statements about prediction accuracy. Additionally, although split-sample testing is recognized as desirable, the split-samples should be selected using a systematic-random sampling scheme, rather than random sampling, because random sampling with small samples may lead to a testing sample that is not representative of the population. A systematic-random sampling technique should lead to more valid conclusions about model reliability. For models like a unit hydrograph model, which are more complex and for which calibration is a more involved process, data independence is not as critical because the data fitting error variation is not as dominant as the error variation due to the calibration process and the inability of the model structure to conform with data variability.     

OPTIMAL RESERVOIR MANAGEMENT AND CROP PLANNING UNDER DETERMINISTIC AND STOCHASTIC INFLOWS1

ABSTRACT: This study analyzes planning under deterministic and stochastic inflows for the Mayurakshi project in India. Models are developed to indicate the optimal storage of reservoir water, the transfer of water to the producing regions, and the spillage of water from the reservoir, if needed. A deterministic programming model was first formulated to represent the existing situation. A chance-constrained model then was constructed to evaluate potential violations of the deterministic model. Both models were quantified for the command area. Data were collected from surveys of the area and from government agencies. Both the deterministic and change-constrained models suggest a more intensive cropping program in the region. Both emphasize more dependence on rabi and less on kharif crops. The chance-constrained especially suggests use of more water in the rabi season. Important chances in cropping programs and labor use take place under the chance-constrained model.     

Air pollution and forest decline in Central Europe

The term 'Waldsterben' was introduced in the early 1980s to describe the progressive death of forests that was believed to be occurring in Central Europe as a result of air pollution. Subsequent surveys and investigations have failed to confirm that forests are dying or are even declining over large areas of Central Europe, defined here as consisting of Germany, Switzerland, southeastern France (Alsace), the Czech Republic, northern Italy and Austria. Foliar injury by air pollutants, together with mortality, has occurred, but is generally restricted to specific locations in the Czech Republic and in eastern Germany, such as the Fichtelgebirge. Where foliar damage has been recorded, it can often be attributed to high concentrations of sulphur dioxide, often acting in combination with other stresses (e.g. frost or insects). Outside areas affected by local sources of pollution, there is little, if any, evidence that the crown condition of trees has been adversely affected by pollution over large areas. Instead, climate appears to have a major effect on the crown condition and growth of trees. Measurements and surveys have revealed a very different picture to that forecasted in the mid-1980s. Growth rates of trees and stands in Central Europe are currently higher than have been recorded at any time in the past; the reasons for this are uncertain, although increases in forest area have not substantially contributed to the observed trends. Although declines in individual species in specific areas have been recorded, past records indicate that these do not represent a new phenomenon. Consequently, the terms 'Waldsterben' (forest deaths) and 'neuartige Waldsch?den' (novel type of forest damages) should not be used in the context of the phenomenon reported in Central Europe in the 1980s. Instead, different problems should be described separately and the term forest decline used only when there is clear evidence of a general deterioration in the condition of all tree species within a forest.     

Metabolic specialization of mitochondria from scallop phasic muscles

In fast, glycolytic muscles, oxidative phosphorylation presumably facilitates recuperation from exhaustive exercise and supports growth and maintenance metabolism. Given the shifts in pH with extensive glycolytic activity, the pH optima of mitochondrial processes should indicate whether mitochondria are adapted for recuperation from exercise or for growth and maintenance. We examined this question using mitochondria from the phasic adductor muscle of the scallop, Euvola (Pecten) ziczac, collected from the Golfo de Cariaco, Venezuela in 1992 and 1993. Scallop muscle mitochondria showed well coupled oxidation of glutamate and pyruvate at pH 7.0 and 6.4. The preferred substrates (glutamate, pyruvate and succinate) were oxidized at approximately 40 nmol O₂ min^-1 mg^-1 mitochondrial protein at 25°C, while malate and glutamine were oxidized at 75% and proline at 30% of these rates. Neither palmitoyl carnitine nor aspartate were oxidized. Succinate oxidation was not coupled to ADP utilization at pH 7.0 but was somewhat coupled at pH 6.4. Generally, State 3 rates of oxygen uptake were similar at pH 7.0 and 6.4. Maximal rates of oxidation of glutamate and pyruvate showed broad pH optima. For both glutamate and pyruvate, the highest respiratory control ratio (RCR) values were found at pH 6.5. The saturation curves of scallop muscle mitochondria for pyruvate, glutamate and ADP were well described by the Michaelis-Menten equation. The affinity for pyruvate was greater at pH 6.4 (apparent K _{m, app}=0.013 mM) than at pH 7.0 (K _{m, app}=0.026 mM) while the affinity for ADP (K _{m, app}=0.015 mM) and that for glutamate (K _{m, app}=0.55 mM) changed little with pH. The ADP affinity was the same whether pyruvate or glutamate was the carbon substrate. The combination of maintenance of sensitivity to ADP with an enhanced affinity for pyruvate at acidic pH values should facilitate recuperation from bouts of glycolytic activity. Scallops harvested in September and those harvested in January differed in the maximal rates of glutamate and pyruvate oxidation.