Toxic effects of endocrine disrupters on freshwater sponges: common developmental abnormalities

Endocrine disrupters are of substantial concern, in large part because effects of these compounds on the growth and development of many aquatic organisms are unknown. We examined toxic effects of three substances (ethylbenzene, nonylphenol, and bisphenol A), that are known to be hormonally active in many animals, on growth and development of two species of freshwater sponge. A common developmental abnormality was observed when sponges were treated with each of these compounds. The three compounds also caused significant reductions in growth rates. Lower concentrations resulted in malformed water vascular systems in several replicates. The utility of freshwater sponge bioassays is discussed as it relates to understanding possible mechanisms of action of endocrine disrupters on aquatic invertebrates.     

Raumbezug und Repr?sentativit?t in der ?kologischen Fl?chenstichprobe

Zusammenfassung  Die Qualit?t von Raumgliederungen kann letztlich nur vor dem Hintergrund des jeweiligen Verwendungskontextes beurteilt werden. Im Bereich der Umweltbeobachtung kommt Raumgliederungen neben ihrer Nutzung zu Analysezwecken inbesondere im Hinblick auf Auswahlverfahren von Untersuchungsfl?chen gro?e Bedeutung zu. Der Beitrag erl?utert den Zusammenhang von Raumgliederung, Auswahlverfahren und Repr?sentativit?t am Beispiel der ?kologischen Fl?chenstichprobe (?FS) und stellt die Gliederung vor, die im Rahmen einer ?FS-Pilotstudie getestet wurde. Online-First: 19. Mai 2000     

Possible control mechanism of cell motility in the gorgonian Eunicella cavolinii

In a previous study it was demonstrated that a lectin controls cell-cell interaction in the gorgonian Eunicella cavolinii (Koch) as a negative modulator. Now we describe the procedure to purify this lectin to homogeneity; its molecular weight is 23 400. The homologous proteoglycans were identified as positive modulators of cell-cell (and/or cell substrate) interaction. The purified single proteoglycan aggregates were 1200±700 nm long and the distance between the attachment points of the proteoglycan subunits was about 45 nm. The glycosaminoglycan residues of the gorgonian proteoglycans were identified as hyaluronic acid (35.5%), heparan sulfate (47.9%) and dermatan sulfate (14.1%). Binding studies with immobilized homologous proteoglycan preparations revealed that gorgonian cells attach to this substratum presumably via its glycosaminoglycans. Quantitative determinations of these two modulators of cell-cell recognition in the three regions of individual colonies revealed concentration gradients these concentration differences reflect a lower cell motility in the polyp-bearing branches and a higher motility of the cells in the polyp-free stem and in the basis, is discussed.     

The Arctic in an earth system context: from brake to accelerator of change

Human activities over the past few centuries have profoundly changed the functioning of the earth system as a whole. These changes are particularly evident in the high latitudes of the Northern Hemisphere, where environmental change has been pronounced and rapid. Such changes have implications beyond the region, as they can lead to two important feedback processes: the ice-albedo feedback and the terrestrial carbon cycle-climate feedback. These processes play an exceptionally important role in earth system functioning, particularly because they may switch this century from damping the effects of anthropogenic climate change to accelerating them. Rapid environmental change in the high latitudes also has consequences for issues of direct importance to humans, particularly water resources.     

Decarboxylation of cinnamic acids using a ruthenium sawhorse

The ruthenium sawhorse has proven effective in the conversion of trans-cinnamic acid, and substituted trans-cinnamic acids, giving an effective source of biobased styrene and styrene analogues. The reaction is especially versatile, as it achieves product without utilising co-reagents. However, the optimum conditions and substrate scope of the reaction remain unexplored. This report covers the decarboxylation of a series of cinnamates with different structures. Apparent activation energies ranging from 66 to 142 kJ mol^?1 were uncovered.     

Forest frontiers out of control: The long-term effects of discourses,policies, and markets on conservation and development of the Brazilian Amazon

With the Brazilian military governments of the 1960s, systematic economic development of the Amazon began. Social and environmental concerns have entered Amazonian discourses and policies only since the 1990s. Since then, reports of threats to forests and indigenous people have alternated with reports of socio-economic progress and environmental achievements. These contradictions often arise from limited thematic, sectoral, temporal, or spatial perspectives, and lead to misinterpretation. Our paper offers a comprehensive picture of discourses, policies, and socio-environmental dynamics for the entire region over the last five decades. We distinguish eight historical policy phases, each of which had little effect on near-linear dynamics of demographic growth and land-use expansion, although some policies showed the potential to change the course of development. To prevent local, national, and international actors from continuing to assert harmful interests in the region, a coherent long-term commitment and change in the collective mindset are needed.     

Real-time wastewater monitoring as tool to detect clandestine waste discharges into the sewage system

The entry of illegally discharged waste into the sewage system can cause serious damage to sewage pipes and harm the public domain. Besides industrial and communal sources, discharges from clandestine laboratories are of special forensic interest. Aim of this study is to investigate the possibility to detect clandestine discharges of possibly hazardous waste directly at the point of discharge. Tests were performed at a facility where real wastewater was pumped in a controlled way through an open sewage pipe above ground. Chloride, ammonia, pH and conductivity electrodes were investigated for their ability to detect discharges of different types of waste. Waste samples were diluted up to 50 times in a static wastewater environment and pH, conductivity and chloride electrodes were able to distinguish all waste dilutions from blank wastewater. These three electrodes were then used for dynamic tests by placing them inside flowing sewage water and discharging different types of liquid waste ten meters upstream of them. Parameters of the waste discharges like volume, time interval and speed of discharge were varied and the responses of the electrodes were collected. The dynamic tests showed that these three electrodes were able to pick up different waste discharges in a real wastewater environment. It was found that a high sampling rate of the sensors would be required to connect a certain discharge to a specific household connection. These findings highlight the possibility to locate illegal discharges, coming from a variety of sources, using the waste discharge itself.     

Who gets the benefit of the doubt? The impact of causal reasoning depth on how violations of gender stereotypes are evaluated

A large body of research demonstrates that women encounter severe penalties for violating gender stereotypes. In this paper, we explore the conditions under which the reverse is true—when being subject to a stereotype can actually benefit a woman compared to a man who is not subject to the same stereotype. In particular, we suggest that in situations of causal ambiguity—uncertainty about the reasons that a behavior occurred—differences in how men and women are evaluated will be moderated by the extent to which observers engage in a low or a high level of deliberative causal reasoning. In 3 experimental studies, participants were asked to make judgments about an employee who violated a female gender stereotype by failing to provide help to a coworker when asked to do so, but the reasons for this behavior were unclear. When participants were prompted to engage in deliberative causal reasoning, women were evaluated more positively than men, but not in the absence of such a prompt. Moreover, when participants did engage in deliberative causal reasoning, the more positive evaluations of women compared to men were driven by participants' beliefs that women's behavior was due more to situational constraints than the same behavior by men.