An evaluation pattern for antimacrofouling procedures: Limnoperna fortunei larvae study in a hydroelectric power plant in South America

The effects of global change and globalization of trade on the biosphere spur an increase in bioinvasions and their subsequent impact on ecosystems. Continental invading bivalves are important because of their impact on artificially-constructed structures. Limnoperna fortunei was first found in the Neotropical region in 1991. Since then it has dispersed upstream in the Plata and Guaíba basins at a rate of 240 km y(-1). This species causes macrofouling in a manner similar to that caused by Dreissena polymorpha. This paper describes the biology of L. fortunei larvae from a hydroelectric power plant in South America. We suggest the importance of knowing the biology of the invading species and the need to consider the settlement patterns and densities of larvae in each of the sectors of the facility in order to achieve a sustainable prevention/control of macrofouling. This study acquires a global significance under the assumption that L. fortunei will eventually invade North America and Europe.     

Evaluation of genotoxicity and toxicity of water and sediment samples from a Brazilian stream influenced by tannery industries

This paper reports results of genotoxicity and toxicity studies of water and sediment samples collected from the Estancia Velha stream of southern Brazil, a stream transporting both domestic sewage and effluents from regional factories working in the leather industry. Three sites were selected: in the stream headwaters (Site 1), located downstream of an urban area (Site 2), and near the basin outfall (Site 3). Results obtained with Allium cepa showed no evidence of chromosomal mutation, either in water or in sediment, during winter or summer seasons, but samples collected below Site 1 showed high toxicity. Physical and chemical analyses showed high concentrations of pollutants at these sites. Ecotoxicity tests with Daphnia magna and Ceriodaphnia dubia measured toxicity in water from Sites 2 and 3 in summer 2004. A toxic effect on Hyalella azteca was only found in sediment from Site 3 during winter 2003 and summer 2004. The results suggest that the synergy among different compounds in domestic and industrial sewage discharges can make it difficult to maintain system stability.     

Bioaccumulation of metals and effects of a landfill in small mammals. Part II. The wood mouse, Apodemus sylvaticus

We assess the bioaccumulation of metals (Pb, Hg, Cd, Fe, Mg, Zn, Cu, Mn, Mo, Cr) and effects of landfill leachates on morphological (RI, relative weights), plasma (GPT, GOT, creatinine), and genotoxic (MNT) parameters in wood mice, Apodemus sylvaticus, inhabiting close the Garraf landfill site (NE Spain). Due to the high age- and sex-dependent variation in wild populations, we also studied the effect of these biotic factors on the parameters studied. Wood mice from the landfill site, sited in a partially protected area, showed more Cd, Fe, Zn, Cu, Mn, Mo, and Cr than specimens from the reference site. Moreover, mice near the landfill registered low RI and high relative renal weight, GPT, and MN frequency, which indicate that the landfill affects the health of wild mice. In contrast to sympatric shrews from a previous study, wood mice showed lower bioaccumulation of metals and lower variation caused by biotic factors. Moreover, the morphological and physiological alterations demonstrated that they were also more sensitive at environmental pollution. Given the contribution of small mammals to ecosystem function and the scarce ecotoxicological data on the effects of landfill pollution on wild terrestrial mammals, we consider that our study can be used to improve the management of this protected area.     

Historical eutrophication in a river-estuary complex in mid-coast Maine.

European settlement of New England brought about a novel disturbance regime that impacted rivers and estuaries through overfishing, deforestation, dams, and water pollution. The negative consequences of these activities intensified with industrialization in the 19th and 20th centuries, often resulting in ecosystem degradation. Since environmental legislation was implemented in the 1970s, improvement in water quality has been tangible and widespread; however, ecological recovery can require substantial amounts of time and may never be complete. To document the natural baseline conditions and investigate the recovery of a severely degraded river-estuary complex in mid-coast Maine, we examined diatoms, pollen, total organic carbon, total nitrogen, stable isotopes, total phosphorus, biogenic silica, and trace metals in intertidal sediments and established a chronology with 14C, 210Pb, and indicator pollen horizons. Both climate variability and human effects were evident in the sedimentary record of Merrymeeting Bay, the freshwater tidal portion of the Kennebec estuary. Natural climate variability was apparent in an episode of high sedimentation and altered diatom abundance during the 12th and 13th centuries and in changing pollen abundances between the 16th and 19th centuries, indicative of regional cooling. During the 18th century, colonial land clearance began an era of high sedimentation and eutrophication that strongly intensified with industrialization during the late 19th and 20th centuries. Improvements in water quality over the past 30 years in response to environmental regulation had little effect on ecosystem recovery as represented by the sedimentary record. Diatom composition and productivity and high fluxes of organic C, total P, and biogenic Si in recent sediments indicate that rates of nutrient loading remain high. These environmental proxies imply that aquatic productivity in Merrymeeting Bay was originally nutrient limited and water clarity high, relative to today. Further recovery may require more stringent regulation of nutrient inputs from industrial and municipal point sources. This historical study can contribute to public debate about the environmental management of this unusual river-estuary complex by describing its long-term natural baseline, thereby illustrating the upper limit of its potential for recovery.     

Accuracy of assessing the level of impulse sound from distant sources.

Impulse sound events are characterised by ultra high pressures and low frequencies. Lower frequency sounds are generally less attenuated over a given distance in the atmosphere than higher frequencies. Thus, impulse sounds can be heard over greater distances and will be more affected by the environment. To calculate a long-term average immission level it is necessary to apply weighting factors like the probability of the occurrence of each weather condition during the relevant time period. This means that when measuring impulse noise at a long distance it is necessary to follow environmental parameters in many points along the way sound travels and also to have a database of sound transfer functions in the long term. The paper analyses the uncertainty of immission measurement results of impulse sound from cladding and destroying explosive materials. The influence of environmental conditions on the way sound travels is the focus of this paper.     

Antecedents,consequences, and moderators of time perspective heterogeneity for knowledge management in MNO teams

Multinational organizations (MNOs), more so than other organizations, are likely to require individuals with different perspectives, experiences, and backgrounds to form teams and collaboratively manage knowledge. We develop a framework that shows why variations in time perspectives among members of teams occur and how such differences can exert significant but unacknowledged influences on knowledge management efforts in MNOs, including: (1) innovativeness of knowledge created (2) speed of knowledge creation and (3) speed of knowledge transfer between teams. We also provide new insights into benefits of time perspective heterogeneity for teams managing knowledge. Copyright © 2007 John Wiley & Sons, Ltd.     

The Political Import of Intrinsic Objections to Genetically Engineered Food

Many people object to genetically engineerehd (GE) food because they believe that it is unnatural or that its creation amounts to playing God. These objections are often referred to as intrinsic objections, and they have been widely criticized in the agricultural bioethics literature as being unsound, incompatible with modern science, religious, inchoate, and based on emotion instead of reason. Many of their critics also argue that even if these objections did have some merit as ethicalobjections, their quasi-religious nature means that they are entirely irrelevant when interpreted aspolitical objections regarding what public policy ought to be. In this paper, we argue that this widespread view is false. Intrinsic objections have much more political import than has previously been recognized, and indeed the requirements of political liberalism and its associated idea of liberal neutrality, once properly understood, protect intrinsic objections from many of the most common objections. That is, policy-makers may not legitimately base public policy on grounds that are inconsistent with intrinsic objections, even when they believe those objections to be flawed in the ways mentioned above. This means that in the context of a political debate about GE food, the discussion should not center on the substantive merits of the intrinsic objections themselves but rather on the appropriate political norms for achieving democratically legitimate policy on issues that touch people’s deepest religious and moral beliefs.     

Effect of sunlight intensity and albinism on the covering response of the Caribbean sea urchin<Emphasis Type="Italic"> Tripneustes ventricosus</Emphasis>

At Discovery Bay, Jamaica, Tripneustes ventricosus lives in beds of the turtle grass Thalassia testudinum. Especially during daylight hours, it covers its aboral surface with fragments of this plant and other objects. Normally pigmented, wild-type sea urchins covered themselves significantly less with Thalassia when sunlight was experimentally decreased to 66% or 32% ambient intensity. Consistent with this result, naturally occurring sea urchins exhibited significantly less covering at a deep (3.5 m) site than at a shallow (1 m) site, where light intensities at the bottom were 619 and 946 mol s^–1 m^–2, respectively. The graded covering response to light intensity suggests that covering is a defense against damaging solar radiation. Albino sea urchins covered themselves significantly more with Thalassia than wild-type sea urchins in both full and 66% sunlight. In addition, at the shallow site where they accounted for about 4% of the population, they showed significantly greater covering than wild-type urchins. The greater covering response of albino sea urchins suggests a greater susceptibility to solar radiation.Communicated by P. W. Sammarco, Chauvin