Polarographic investigations on the complexation of cadmium and zinc by thiol peptides

Complex formation of Cd²⁺ and Zn²⁺ with thiol derivatives has been investigated by differential pulse polarography. The binding of Cd²⁺ and Zn²⁺ with cysteine (CySH), glutathione (GSH) and the model peptide N‐acetyl‐cysteine‐methylamide (ASH) reveals different stoichiometry. Thus, Cd²⁺ forms 1:1 and 1:2 complexes with CySH while 1:2 and 1:4 complexes have been observed with GSH and ASH, respectively. Overall formation constants of Cd²⁺ with CySH (Iogβ ₂ 15.3) and with GSH (Iogβ5₂ 14.4) have been estimated using competitive complexation with nitrilotriacetic acid (NTA). Investigation of competition between Zn²⁺ and Cd²⁺ for the thiol complexation has underlined the role played by the amino group in CySH for the stabilization of Zn complexes in contrary to Cd complexes.     

Does the stock market value the inclusion in a sustainability stock index? An event study analysis for German firms

This paper empirically analyzes the effect of the inclusion of German corporations in the Dow Jones STOXX Sustainability Index (DJSI STOXX) and the Dow Jones Sustainability World Index (DJSI World) on stock performance. In order to receive robust estimation results, we apply an (short-term) event study approach that is based on both a modern asset pricing model, namely the three-factor model according to Fama and French [24], and additionally a t-GARCH(1,1) model. Our empirical results suggest that stock markets may penalize the inclusion of a firm in sustainability stock indexes. This finding is mainly driven by a strongly negative effect of the inclusion in the DJSI World. In contrast, we do not find significant average cumulative abnormal returns for the inclusion in the DJSI STOXX. This suggests that the inclusion in a more visible sustainability stock index may have larger negative impacts.     

The influence of collection facility attributes on household collection rates of electronic waste: The case of televisions and computer monitors

In the US, household electronic waste collected for recycling is primarily by voluntary drop-off at designated collection facilities. This study examines the influence of specific collection facility attributes (recycling fees charged, number of days open, and driving distance) on the household collection rate of e-waste in the US state of Maine. Data were collected for household computer monitor and television collection for 92 municipal waste transfer facilities representing 30% of the state's population for one year. Results suggest that recycling fees are negatively correlated with the number of televisions and computer monitors collected; furthermore, the more frequently facilities were open, the more televisions and computer monitors were collected per capita. The distance from the facility had no correlation, which prompted an analysis of whether the existence of a curbside collection system in the municipality was influential. Results show a negative correlation between computer monitor and television collection and a municipality having recycling (but not e-waste) curbside collection. Based on the results of this study, policymakers may be able to increase the collection rate of household e-waste by eliminating or lowering recycling fees, expanding collection days and hours to increase convenience, and/or considering curbside collection of e-waste.     

Whistle communication in mammal-eating killer whales (Orcinus orca): further evidence for acoustic divergence between ecotypes

Public signaling plays an important role in territorial and sexual displays in animals; however, in certain situations, it is advantageous to keep signaling private to prevent eavesdropping by unintended receivers. In the northeastern Pacific, two populations of killer whales (Orcinus orca), fish-eating “resident” killer whales and mammal-eating “transient” killer whales, share the same habitat. Previous studies have shown that residents use whistles as private signals during close-range communication, where they probably serve to coordinate behavioral interactions. Here, we investigated the whistling behavior of mammal-eating killer whales, and, based on divergent social structures and social behaviors between residents and transients, we predicted to find differences in both whistle usage and whistle parameters. Our results show that, like resident killer whales, transients produce both variable and stereotyped whistles. However, clear differences in whistle parameters between ecotypes show that the whistle repertoire of mammal-eating killer whales is clearly distinct from and less complex than that of fish-eating killer whales. Furthermore, mammal-eating killer whales only produce whistles during “milling after kill” and “surface-active” behaviors, but are almost completely silent during all other activities. Nonetheless, whistles of transient killer whales may still serve a role similar to that of resident killer whales. Mammal-eating killer whales seem to be under strong selection to keep their communication private from potential prey (whose hearing ranges overlap with that of killer whales), and they appear to accomplish this mainly by restricting vocal activity rather than by changes in whistle parameters.     

Occurrence of PCBs in raw and finished drinking water at seven public water systems along the Hudson River

Polychlorinated biphenyls (PCBs) were measured in raw and finished drinking water at seven Public Water Systems (PWSs) along the Hudson River as part of a baseline monitoring program prior to the extensive sediment dredging of the Upper Hudson River. Water samples were either analyzed using an Aroclor method (based on USEPA Method 508) or a congener method (Modified Green Bay Mass Balance Method). Using the congener-based method, raw water concentrations ranged from <9.3 to 164.3 ng/L and finished water concentrations ranged from <9.3 to 186.6 ng/L. Using the Aroclor method, finished water concentrations ranged from <5.0 to 200.9 ng/L. Most finished water samples above 73.0 ng/L were from a PWS with wells drilled near the river. Excluding the well data, total PCB concentrations in raw water at systems in the Upper River were similar to concentrations at systems in the Lower River, though the congener patterns differed. Paired comparison of total PCB concentrations using the two analytical methods showed good agreement, although raw water showed a different relationship than finished water.     

Brick production with dredged harbour sediments. An industrial-scale experiment

A volume of 600.000 m3 harbour sediments is annually dredged out of the harbour basin of Bremen to maintain a certain water depth. Because of its perpetual availability, homogeneity and mineralogical, petrographic and chemical composition, the sediment is regarded as a suitable raw material for brick production. A pilot experiment was conducted at a full-scale industrial brickworks. During production, the environmental standards concerning waste-water treatment and the quality of exhausted gas were sufficiently fulfilled. Bricks specified as "building bricks" were produced according to German industrial standards. The parameters pH-value and grain size were varied in leaching tests performed on the bricks as both parameters are likely to change in the course of the brick's life cycle. The leaching data showed that As was stabilised and heavy metals were immobilised in a way that the bricks were not (hazardous to soil or groundwater) neither by their use, for example, in masonry, nor afterwards, when they will be deposited as mineral demolition mass.     

Proposing an information criterion for individual-based models developed in a pattern-oriented modelling framework

Individual-based models (IBMs) have been improved in quality and reliability in recent years with an approach called pattern-oriented modelling (POM). POM proposes guidelines to develop models reproducing multiple patterns observed on the field and to test systematically how well the IBMs reproduce them. POM studies used generally traditional methods of goodness of fit such as the sum of squares evaluation or ad hoc comparisons of fitting errors and variations. Model selection, however, can be a rigorous statistical approach based on information theory and information criteria such as the Akaike's information criterion (AIC) or the deviance information criterion (DIC). So far, it has not been tried to link POM to these rigorous techniques. The main problems to achieve that are: (a) the difficulty to have likelihood functions for IBMs’ parameters and (b) the possibility to obtain posterior distributions of IBMs’ parameters given the patterns to reproduce. In a first part, this paper answers problem (a) by proposing and explaining how to calculate a deviance measure (POMDEV) for models developed in a context of POM. And while answering the second problem, a second part of the paper proposes an information criterion for model selection in a POM context (the pattern-oriented modelling information criterion: POMIC). This criterion does not yet have the same theoretical foundation as, e.g., AIC, but uses formal analogies to the DIC. In a third part POMIC is tested with a modelling exercise. This exercise shows the potential of POMIC to use multiple patterns for selecting among multiple potential submodels and eventually select the most parsimonious and well fitting model version. We conclude that POMIC, although being a heuristically derived approach, can greatly improve the POM framework.     

INTEGRATING DEMOGRAPHIC AND LANDSAT (TM) DATA AT A WATERSHED SCALE1

ABSTRACT: Recurrent calls for integrated resource management urge that an understanding of human activities and populations be incorporated into natural resource research, management, and protection efforts. In this paper, we hypothesize that watersheds can be a valuable geography for organizing an inquiry into the relationship between humans and the environment, and we present a framework for conducting such efforts. The framework is grounded in the emerging field of landscape ecology and incorporates demographic theory and data. Demography has been advanced by technological capabilities associated with the 1990 Census. Employing Geographic Information System (GIS) tools, we couple Landsat Thematic Mapper (TM) land cover data with census‐derived housing density data to demonstrate the operation of our framework and its utility for better understanding human‐landscape interactions. In our investigation of the Kickapoo Watershed and two sub‐ watersheds, located in southwestern Wisconsin, we identify relationships between landscape composition and the distribution and social structure of human populations. Our findings offer insight into the interplay between people and biophysical systems.     

Persistence revisited

We are happy and proud to announce that our book ‘Atmospheric Degradation of Organic Substances — Data for Persistence and Long-range Transport’ (see pp. 143–144) has recently been published by Wiley-VCH [1]. It contains a critical compilation of photo degradation rate constants and quantum efficiencies relevant for calculating the atmospheric persistence of volatile and a few semi-volatile organic compounds. In addition to the data of nearly 1100 substances, the importance of persistence in air and long-range transport potential is presented in two chapters from the point of view of chemicals legislation and of atmospheric photochemistry.