Bench‐ and pilot‐scale applications of electrochemical peroxidation: A new remedial concept

Electrochemical peroxidation (ECP) is a proprietary process that utilizes sacrificial iron electrodes and stochiometrically balanced applications of hydrogen peroxide to efficiently destroy aqueous phase contaminants. In laboratory trials it has been successful in reducing, often to non‐detectable levels, BTEX, fuel additives, chlorinated solvents, and polychlorinated biphenyls in ground waters. The process has also been found effective in reducing the chemical and biological oxygen demand of industrial waste water. Agency‐approved pilot tests will be conducted at two gasoline spill sites during 2000 where traditional pump and treat methods have proven ineffectual because of ground water chemistry or subsurface hydrologic conditions. The ECP process utilizes a tripartite treatment strategy consisting of 1) ex situ chemical oxidation; 2) in situ oxidation by reinjection of treated water with residual oxidants at the head of the plume; and 3) reestablishment of aerobic biodegradation by alteration of subsurface redox conditions. In contrast to other in situ oxidation treatment methods, dissolved iron is derived electrochemically, negating the need for ferrous salt addition. Dilute hydrogen peroxide (3 percent) is incrementally added to maximize oxidation efficiency and eliminate safety and environmental concerns accompanying the use of highly concentrated solutions. Results of laboratory trials and the geological and geochemical considerations of upcoming pilot‐scale applications are presented. Other potential applications currently under investigation include combination with other remedial processes (e.g. permeable barriers and hydrogen release compounds) to insure complete and rapid contaminant mineralization.     

EXTERNALITIES,WATER PRICES,AND WATER TRANSFERS1

Discussing, estimating or analyzing the value of water is a difficult task. In addressing the value of water as reflected in its price — either as charged by a water utility, as the price of a water transfer, or a water sale in some market — this paper will examine three propositions regarding water pricing. The paper will consider the marginal scarcity rent of water, estimates of externalities, the full cost pricing of water and the consequences of these considerations on water prices, transfers and the efficiency of water use.     

Visitor Evaluations of Management Actions at a Highly Impacted Appalachian Trail Camping Area

Protected area management involves balancing environmental and social objectives. This is particularly difficult at high-use/high-impact recreation sites, because resource protection objectives may require substantial site management or visitor regulation. This study examined visitors’ reactions to both of these types of actions at Annapolis Rocks, Maryland, a popular Appalachian Trail camping area. We surveyed visitors before and after implementation of camping policies that included shifting camping to designated newly constructed campsites and prohibiting campfires. Survey results reveal that visitors were more satisfied with all social and environmental indicators after the changes were enacted. An Importance-Performance analysis also determined that management actions improved conditions for factors of greatest concern to campers prior to the changes. Posttreatment visitors were least satisfied with factors related to reduced freedom and to some characteristics of the constructed campsites. Although there was evidence of visitor displacement, the camping changes met management goals by protecting the camping area’s natural resources and improving social conditions.     

Short- and Longer-Term Effects of Fire and Herbivory on Sagebrush Communities in South-Central Montana

To better understand the role of herbivory and fire as potential disturbance processes in sagebrush communities, we examined responses of a grazing ungulate, elk (Cervus elaphus), following prescribed burning of sagebrush (Artemisia tridentata ssp. vaseyana) in south-central Montana (USA.) with concurrent monitoring of changes in plant production, nutritional quality, and community diversity from 1989–1999. Burning transformed low-diversity, sagebrush-dominated communities into high-diversity, graminoid-forb communities that persisted for 10 years without significant reestablishment of sagebrush. Elk increased use of burned sites one year after burning, but elk use returned to pre-burn levels over the next two to nine years. Forage biomass and nutritional quality declined after initial increases that coincided with increased elk use. Increases in elk use appeared to be influenced by increases in combined graminoid and forb production and changes in structural vegetation characteristics that permitted greater foraging efficiency. Declines in use were associated with loss of nutritional enhancement and declines in combined graminoid and forb production. Managers may observe only short-term responses from grazing ungulates to prescribed fire in sagebrush communities, but can expect longer-term increases in plant diversity and establishment of graminoid-forb communities.     

Predicting how defaunation-induced changes in seed predation and dispersal will affect tropical tree populations

The loss of large animals due to overhunting and habitat loss potentially affects tropical tree populations and carbon cycling. Trees reliant on large-bodied seed dispersers are thought to be particularly negatively affected by defaunation. But besides seed dispersal, defaunation can also increase or decrease seed predation. It remains unclear how these different defaunation effects on early life stages ultimately affect tree population dynamics. We reviewed the literature on how tropical animal loss affects different plant life stages, and we conducted a meta-analysis of how defaunation affects seed predation. We used this information to parameterize models that altered matrix projection models from a suite of tree species to simulate defaunation-caused changes in seed dispersal and predation. We assessed how applying these defaunation effects affected population growth rates. On average, population-level effects of defaunation were negligible, suggesting that defaunation may not cause the massive reductions in forest carbon storage that have been predicted. In contrast to previous hypotheses, we did not detect an effect of seed size on changes in seed predation rates. The change in seed predation did not differ significantly between exclosure experiments and observational studies, although the results of observational studies were far more variable. Although defaunation surely affects certain tree taxa, species that benefit or are harmed by it and net changes in forest carbon storage cannot currently be predicted based on available data. Further research on how factors such as seed predation vary across tree species and defaunation scenarios is necessary for understanding cascading changes in species composition and diversity.     

Protected area planning to conserve biodiversity in an uncertain future

Protected areas are a key instrument for conservation. Despite this, they are vulnerable to risks associated with weak governance, land-use intensification, and climate change. We used a novel hierarchical optimization approach to identify priority areas for expanding the global protected area system that explicitly accounted for such risks while maximizing protection of all known terrestrial vertebrate species. To incorporate risk categories, we built on the minimum set problem, where the objective is to reach species distribution protection targets while accounting for 1 constraint, such as land cost or area. We expanded this approach to include multiple objectives accounting for risk in the problem formulation by treating each risk layer as a separate objective in the problem formulation. Reducing exposure to these risks required expanding the area of the global protected area system by 1.6% while still meeting conservation targets. Incorporating risks from weak governance drove the greatest changes in spatial priorities for protection, and incorporating risks from climate change required the largest increase (2.52%) in global protected area. Conserving wide-ranging species required countries with relatively strong governance to protect more land when they bordered nations with comparatively weak governance. Our results underscore the need for cross-jurisdictional coordination and demonstrate how risk can be efficiently incorporated into conservation planning. Planeación de las áreas protegidas para conservar la biodiversidad en un futuro incierto     

Pyrrhic victories: the cost to the board of ousting the CEO

Going against anecdotal evidence and common perception, the findings presented here show that boards who take action against their CEOs do so only at great cost to themselves, winning only a pyrrhic victory. Indeed, the findings presented show three distinct levels of board turnover. Normal attrition in periods of continuity produced a turnover of 10.99 per cent over two years; routine retirement exists (22.35 per cent) produced a similar turnover level to forced exits which did not imply a failure of the board to perform its monitoring function (25.36 per cent). However, forced CEO exits which implied a failure in the board's monitoring and advising roles caused a dramatically higher level of subsequent board turnover (40.55 per cent). These findings demonstrate that is not only the CEO that is forced to sacrifice his or her job when a company is in distress, but that the board is also accountable for its failure to perform its monitoring and advising duties adequately. Copyright © 1999 John Wiley & Sons, Ltd.     

A theoretical integration of leader emergence and leadership effectiveness: Over,under, and congruent emergence

There is a long and rich history of research on the concept of leader emergence. Much of this research positions leader emergence alongside leadership effectiveness as an epiphenomenal criterion in leadership research. Although this view has enhanced our understanding of factors that influence leader emergence and leadership effectiveness individually, our understanding of the potential alignment or misalignment of these concepts remains opaque. Following from this, we are left with unanswered questions concerning how, why, and under what conditions do the right or wrong leaders emerge or fail to emerge. Theory that develops insights into these questions is needed to advance our understanding of leadership and to cope with challenges of identifying and developing effective leaders and maximizing leadership potential in organizations. By integrating theories of leader emergence and leadership effectiveness—and considering their implications jointly—we provide a conceptual basis for identifying and understanding a more complete range of leader emergence than has been suggested in the literature. Importantly, our theoretical frame explains how our leader emergence types—over-emergence, under-emergence, congruent emergence, and congruent non-emergence—are differentially associated with a common set of factors. In doing so, we illuminate tradeoffs that might accompany different interventions intended to enhance leadership in organizations.