Optimal Foraging, Institutions and Forest Change: A Case from Nepal

The forest composition we witness today is a productof temporal anthropogenic and nonanthropogenicdisturbances. Scholars from geography, anthropology,and other disciplines have long been aware of theinforming nature of spatial relationships: humanactions in a previous time often leave imprints intoday's landscape. Traditional empirical studies offorest condition typically ignore this type ofinformation and rely on aggregated forest-levelindicators developed from aspatial plot-levelanalyses. This paper conducts a spatial analysis ofone important forest product species, Shorearobusta, in a foraging setting in southern Nepal. Forest plot locations were located using DifferentialGlobal Positioning Systems (DGPS) and were processedusing a Geographic Information System. Three rivalhypotheses of the geographic distribution of Shorea robusta are presented: (1) a pattern of nohuman disturbance, (2) a pattern of open access andoptimal foraging, and (3) a pattern of optimalforaging altered by the geographic configuration ofenforced institutions. Multivariate regression modelsare estimated and optimal foraging patterns areidentified. Statistical tests lend support to thethird hypothesis. Methods such as the ones presentedhere are important if we are to better understand thegeographic implications of institutional design onhuman behavior and the environmental outcomes that result.     

Land use change and carbon exchange in the tropics: I. Detailed estimates for Costa Rica,Panama, Peru,and Bolivia

Our group, composed of modelers working in conjunction with tropical ecologists, 3 has produced a simulation model that quantifies the net carbon exchange between tropical vegetation and the atmosphere due to land use change. The model calculates this net exchange by combining estimates of land use change with several estimates of the carbon stored in tropical vegetation and general assumptions about the fate of cleared vegetation. In this report, we use estimates of land use and carbon storage organized into sixlife zone (sensu Holdridge) categories to calculate the exchange between the atmosphere and the vegetation of four tropical countries. Our analyses of these countries indicate that this life zone approach has several advantages because (a) the carbon content of vegetation varies significantly among life zones, (b) much of the land use change occurs in life zones of only moderate carbon storage, and (c) the fate of cleared vegetation varies among life zones. Our analyses also emphasize the importance of distinguishing between temporary and permanent land use change, as the recovery of vegetation on abandoned areas decreases the net release of carbon due to clearing. We include sensitivity analysis of those factors that we found to be important but are difficult to quantify at present.     

Scent-marking behavior in wild groups of common marmosets (Callithrix jacchus)

Scent-marking in mammals has been frequently related to within-group social and reproductive dominance and to defense of territory and resources. We studied the scent-marking behavior of five wild groups of common marmosets, Callithrix jacchus, during 5 months of the fruiting season in northeastern Brazil. Circumgenital marking was the most common type of marking. Marks were distributed throughout the home range and were deposited mainly during travel and intergroup encounters. Although marks were commonly deposited at gum trees, there was no evidence that the animals used scent marks to label fruiting trees or sleeping sites. Contrary to expectations, reproductively dominant females did not mark more than reproductively subordinate females. Moreover, during intergroup encounters, reproductively subordinate females displayed higher frequencies of scent-marking than the reproductively dominant females of their group. Our results suggest that scent-marking is not strictly tied to reproductive dominance or territorial (or resource) defense in common marmosets. Because marks provide information about individual identity and reproductive condition, scent marks could serve different functions when used by different individuals. The high frequency of marking by reproductively subordinate females during intergroup encounters suggests that scent-marking might be used to signal to individuals of neighboring groups. Our data highlight the importance of social and ecological variables in scent-marking behavior. Received: 26 October 1998 / Received in revised form: 20 May 1999 / Accepted: 30 May 1999     

Differences in the importance of work outcomes between full-time and part-time hospital employees

This study examined differences in the importance of work outcomes between full-time and part-time hospital employees in a sample drawn from five western hospitals (N = 1,876). Work status was operationalized by classifying respondents into four categories based on hours worked per week. Exploratory factor analysis showed that work outcomes may be classified as extrinsic (pay and fringe benefits) and instrinsic (being informed about the job, participating in decision-making, and doing the job well). Confirmatory factor analyses demonstrated that this two-factor structure fits the data well for all four work status categories although the factor loadings differed across categories. Multivariate analyses of variance and covariance indicated that statistically significant differences in the importance of extrinsic and intrinsic outcomes exist for full-time and part-time employees and that these differences persist when various social and demographic variables are held constant. Employees who work fewer hours per week tend to assign less importance to the work outcomes measured in this study. The results suggest that theoretical models of variables such as job satisfaction should take into account work status differences in the importance of work-related outcomes. In addition, managers may find that workers respond to different reward structures depending on the degree of their involvement in the organization.     

AN ARCHETYPAL LINEAR PROGRAMMING MODEL FOR OPTIMAL INTERTEMPORAL ALLOCATION OF GROUNDWATR TO AGRICULTURAL ACTIVITIES1

ABSTRACT: In the past, researchers have applied a variety of analytical techniques for maximizing the present value of a stock resource - simulation, calculus of variations, stochastic dynamic programming, and optimal control theory. This paper presents a more operational approach - linear programming. A simplified, broadly drawn example from Southwest agriculture is used for demonstrating the model's structure and output. The method is based on a set of state transformation operations that prevent the additivity assumption of linear programming from being violated.     

Modeling the relationship between development and storm water and nutrient runoff

The EPA Storm Water Management Model was used to model the effects of urban and agricultural development on storm water runoff from uplands bordering a Louisiana swamp forest. Using this model, we examined the effects of changing land use patterns. By 1995 it is projected that urban land on the uplands bordering the swamp will increase by 321 percent, primarily at the expense of land currently in agriculture. Simulation results indicate that urbanization will cause storm water runoff rates to be up to 4.2 times greater in 1995 than in 1975. Nutrient runoff will increase 28 percent for nitrogen (N) and 16 percent for phosphorus (P) during the same period. The environmental effects of these changes in the receiving swamp forest are examined.     

WATER TRANSFERS AND THEIR IMPACTS: LESSONS FROM THREE COLORADO WATER MARKETS1

ABSTRACT: This paper presents an analysis of the effects of different institutional arrangements and economic environments on water markets. Characteristics of water rights transfers in the South Platte Basin of Colorado and transfers of shares of the Northern Colorado Water Conservancy District (NCWCD) are compared to show how different institutional arrangements can affect the types and size distributions of transfers. The characteristics of water rights transfers in the prosperous South Platte are then compared with water rights transfer characteristics in the economically marginal Arkansas River basin of Colorado to identify the effects of different economic environments. Finally, the economic losses from reductions in irrigated acreage resulting from water transfers are estimated for the South Platte and Arkansas and compared with purchase prices by municipalities. Transfers in the South Platte were to new uses in the same basin, while more recent transfers in the Arkansas were to out of basin users. Transfers of South Platte rights and especially NCWCD shares were small and continuous over time, while transfers in the Arkansas were dominated by a few very large transfers. The negative impacts are judged to be more severe in the Arkansas basin than in the South Platte. Purchase prices paid by municipalities substantially exceeded capitalized transitional losses in the selling areas. In the South Platte, gains and losses were in the same basin, while the Arkansas absorbed the losses, with the benefits going to the purchasing basin.     

Reclamation of the Urad molybdenum mine,Empire, Colorado

The Urad Mine, located at an elevation of 10,400 feet near the Continental Divide in central Colorado, was operated from 1967–1974 by AMAX Inc. Mine related activities disturbed approximately 234 acres, of which two tailing deposition areas comprised 121 acres. Comprehensive reclamation was initiated prior to mine closure in 1974 and was completed in 1980.Conventional revegetation techniques were implemented on typical disturbances while the tailing areas were reclaimed with the aid of three waste products. Mine waste rock was used to cap the tailing areas, and sewage and wood wastes were used to convert the rock into a rudimentary soil. The rock was revegetated and the vegetation is now permanent and selfsustaining.     

Indoor Fine Particles: The Role of Terpene Emissions from Consumer Products

Abstract

Consumer products can emit significant quantities of terpenes, which can react with ozone (O₃). Resulting byproducts include compounds with low vapor pressures that contribute to the growth of secondary organic aerosols (SOAs). The focus of this study was to evaluate the potential for SOA growth, in the presence of O₃, following the use of a lime-scented liquid air freshener, a pine-scented solid air freshener, a lemon-scented general-purpose cleaner, a wood floor cleaner, and a perfume. Two chamber experiments were performed for each of these five terpene-containing agents, one at an elevated O₃ concentration and the other at a lower O₃ concentration. Particle number and mass concentrations increased and O₃ concentrations decreased during each experiment. Experiments with terpene-based air fresheners produced the highest increases in particle number and mass concentrations. The results of this study clearly demonstrate that homogeneous reactions between O₃ and terpenes from various consumer products can lead to increases in fine particle mass concentrations when these products are used indoors. Particle increases can occur during periods of elevated outdoor O₃ concentrations or indoor O₃ generation, coupled with elevated terpene releases. Human exposure to fine particles can be reduced by minimizing indoor terpene concentrations or O₃ concentrations.     

Evaluation of the effectiveness of traffic calming measures on vehicle speeds and pedestrian injury severity in Ghana

Objectives: Each year, pedestrian injuries constitute over 40% of all road casualty deaths and up to 60% of all urban road casualty deaths in Ghana. This is as a result of the overwhelming dependence on walking as a mode of transport in an environment where there are high vehicular speeds and inadequate pedestrian facilities. The objectives of this research were to establish the (1) impact of traffic calming measures on vehicle speeds and (2) association between traffic calming measures and pedestrian injury severity in built-up areas in Ghana.

Method: Vehicle speeds were unobtrusively measured in 38 selected settlements, including 19 with traffic calming schemes and 19 without. The study design used in this research was a matched case–control. A regression analysis compared case and control casualties using a conditional logistic regression.

Results: Generally, the mean vehicle speeds and the proportion of vehicles exceeding the 50?km/h speed limit were significantly lower in settlements that have traffic calming measures compared to towns without any traffic calming measures. Additionally, the proportion of motorists who exceeded the speed limit was 30% or less in settlements that have traffic calming devices and the proportion who exceeded the speed limit was 60% or more in towns without any traffic calming measures. The odds of pedestrian fatality was significantly higher in settlements that have no traffic calming devices compared to those that have (odds ratio [OR]?=?1.98; 95% confidence interval, 1.09–4.43). The protective effects of a traffic calming scheme that has a speed table was notably higher than those where there were no speed tables.

Conclusion: It was clearly evident that traffic calming devices reduce vehicular speeds and, thus, the incidence and severity of pedestrian injuries in built-up areas in Ghana. However, the fact that they are deployed on arterial roads is increasingly becoming a road safety concern. Given the emerging safety challenges associated with speed calming measures, we recommend that their use be restricted to residential streets but not on arterial roads. Long-term solutions for improving pedestrian safety proposed herein include bypassing settlements along the highways to reduce pedestrians’ exposure to traffic collisions and adopting a modern way of enforcement such as evidence-based laser monitoring in conjunction with a punishment regime that utilizes the demerit points system.