The electro-oxidation of tetracycline hydrochloride in commercial DSA® modified by electrodeposited platinum

Environmental Science and Pollution Research - Tetracycline hydrochloride (TCH) electro-oxidation by commercial DSA® and commercial DSA® modified by platinum electrodeposition was...     

Combining motions into complex displays: playbacks with a robotic lizard

Complex displays composed of multiple, seemingly independent, units can result from sexual selection for increasingly variable, but redundant, displays and from potentially opposing selective pressures imposed by use of the display in multiple contexts. Our playback results support the latter, multireceiver hypothesis by confirming that two aspects of the sagebrush lizard headbob display (number of headbobs and use of display-specific body postures) are independently-meaningful components that are interpreted differently by different receivers. Male receivers use species-typical body postures to distinguish between aggressive and broadcast forms of the display, whereas female receivers are more attentive to the number of headbob motions, using these to distinguish male courtship from a challenge from a female competitor. Thus, display components are likely subject to different selective pressures and the display as a whole is evolving in response to a complex selective regime. Our example differs from other complex signals that have been considered in that both display elements involve dynamic motions (turned on and off by the display producer) as opposed to static signal elements (e.g., color, size). In addition, we found evidence that display structure is highly malleable, and that lizards both produce and respond to artificial displays that violate syntactic rules identified from field observations. Finally, our experiments demonstrate that a robotic lizard can be used effectively in playback studies of visual display behavior in lizards.Electronic Supplementary Material: S1. Movie clip of the robotic lizard producing a species-typical headbob display as in Fig. 1a.     

The Tourism Carrying Capacity of Underwater Trails in Isabel Island National Park, Mexico

The popularity of ecotourism in the marine protected areas of Mexico has increased over the last 10 years; in particular there is a large development of a SCUBA diving industry in the Mexican Pacific including Isabel Island. Given the risks associated with human activity in the marine environments around this island, we propose two ecotourism management strategies: (1) the creation and use of underwater trails, and (2) the estimation of the specific tourism carrying capacity (TCC) for each trail. Six underwater trails were selected in sites that presented elements of biological, geological, and scenic interest, using information obtained during field observations. The methodology used to estimate the TCC was based upon the physical and biological conditions of each site, the infrastructure and equipment available, and the characteristics of the service providers and the administrators of the park. Correction factors of the TCC included elements of the quality of the visit and the threat and vulnerability of the marine environment of each trail (e.g., divers’ expertise, size and distance between groups of divers, accessibility, wind, coral coverage). The TCC values ranged between 1,252 and 1,642 dives/year/trail, with a total of 8,597 dives/year for all six trails. Although these numbers are higher than the actual number of recreational visitors to the island (~1,000 dives per year), there is a need for adequate preventive management if the diving sites are to maintain their esthetic appeal and biological characteristics. Such management might be initially directed toward using only the sites and the TCC proposed here.     

Health effects of ozone focusing on childhood asthma: What is now known – a review from an epidemiological point of view

Protecting the health of children and the environment is an essential objective for the health policies of any modern society, being also crucial for a sustainable development, according to the World Health Organization. Evaluating the risk of developing childhood asthma is one of the four priority issues identified by the European Commission, according to the European Union Environment and Health Action Plan.Accordingly, this review aimed to update information concerning the effects of exposure to ozone on childhood asthma, thus helping in the development of strategies for further research. Studies have been demonstrating strong associations between the exposure to ozone and asthma. However, the complexity of exposure patterns, the changes in the vulnerability of children at various stages of development, and the practical limitations of research, lead to a still incomplete understanding of the ozone impact on the health of children. Difficulties on the interpretation of epidemiological studies to evaluate chronic effects are mainly due to an absence of studies designed specifically to address this question and to inherent limitations in characterizing exposure. The more rigorous studies provided new evidences for chronic effects of ozone on small airway function and possibly on asthma, but substantial uncertainties remain.     

Antibiotic resistance of Enterococcus spp. isolated from wastewater and sludge of poultry slaughterhouses

Antibiotimicrobial resistance was investigated in 537 Enterococcus spp. isolates recovered from 22 samples of crude inflow, treated effluent and sludge collected in wastewater treatment plants of eight poultry slaughterhouses of Portugal. No significant differences (P > 0.05) were found in the resistance to each antimicrobial agent with regards to the origin of the sample (inflow, sludge and effluent). Many of the isolates displayed resistance to tetracycline (85.7%), erythromycin (45.7%), nitrofurantoin (34.0%) and rifampicin (17.8%). Resistance was also observed, but to a lesser extent, to ciprofloxacin (10.2%), ampicillin (8.0%), chloramphenicol (4.6%), vancomycin (0.9%) and gentamicin (0.4%). Resistance to three or more antimicrobial classes was present in 37.1% of the isolates. Wastewater treatment resulted in viable enterococci decrease between less than 1 log and 4 log; nevertheless, more than 4.4 x 10(5) colony forming units (CFU)/100 mL were present in the outflow of the plants and thus resistant enterococci are not prevented from reaching the general environment.     

SITE Demonstration of Enhanced In-Situ Bioremediation of Chlorinated and Nonchlorinated Organic Compounds in Fractured Bedrock

A field demonstration of an enhanced in-situ bioremediation technology was conducted between March 1998 and August 1999 at the ITT Industries Night Vision (ITTNV) Division plant in Roanoke, Virginia. The bioremediation process was evaluated for its effectiveness in treating both chlorinated and nonchlorinated volatile organic compounds (VOCs) in groundwater located in fractured bedrock. Chlorinated compounds, such as trichloroethene (TCE), in fractured bedrock pose a challenging remediation problem. Not only are chlorinated compounds resistant to normal biological degradation, but the fractured bedrock presents difficulties to traditional techniques used for recovery of contaminants and for delivery of amendments or reagents for in-situ remediation. The demonstration was conducted under the U.S. Environmental Protection Agency's Superfund Innovative Technology Evaluation (SITE) program. The SITE program was established to promote the development, demonstration, and use of innovative treatment technologies for the cleanup of Superfund and other hazardous waste sites. This article presents selected results of the demonstration and focuses on understanding the data in light of the fractured bedrock formation. © 2002 Wiley Periodicals, Inc.     

PARAMETER IDENTIFICATION IN A TWO‐MULTIPLIER SEDIMENT YIELD MODEL1

ABSTRACT: A process based, distributed runoff erosion model (KINEROS2) was used to examine problems of parameter identification of sediment entrainment equations for small watersheds. Two multipliers were used to reflect the distributed nature of the sediment entrainment parameters: one multiplier for a raindrop induced entrainment parameter, and one multiplier for a flow induced entrainment parameter. The study was conducted in three parts. First, parameter identification was studied for simulated error free data sets where the parameter values were known. Second, the number of data points in the simulated sedigraphs was reduced to reflect the effect of temporal sampling frequency on parameter identification. Finally, event data from a small range‐land watershed were used to examine parameter identifiability when the parameter values are unknown. Results demonstrated that whereas unique multiplier values can be obtained for simulated error free data, unique parameter values could not be obtained for some event data. Unique multiplier values for raindrop induced entrainment and flow induced entrainment were found for events with greater than a two‐year return period (～25 mm) that also had at least 10 mm of rain in ten minutes. It was also found that the three‐minute sampling frequency used for the sediment sampler might be inadequate to identify parameters in some cases.     

Brood reduction in response to manipulated brood sizes in the common swift (Apus apus)

Following a brood size manipulation experiment on the common swift (Apus apus) in which different levels of parental effort were created, brood reduction occurred in all five nests manipulated to four chicks and in two of the five manipulated to three young. This provided an opportunity for looking in detail at the parental investment decisions concerning allocation strategies between parent and young during the process of brood reduction. The data recorded here were analysed on a visit-by-visit basis regarding changes in parental and chick body masses, the mass of prey delivered and the estimated mass of parental self-feeding. The results show that food delivery rates did not increase in proportion to the number of chicks in the broods. This reduction in delivery rates per chick resulted in lower chick masses and ultimately in the death of one or more chicks in the larger broods. The resulting low parental body masses for adult birds feeding larger broods suggested that these parents could not have raised all their young without risking their own survival. There was a tendency for parents from nests that experienced brood reduction to feed themselves instead of allocating most of the food gathered to the young. After brood reduction, parents regained lost body mass and their young fledged at masses only slightly lower than normal. The differential allocation decisions regarding parental self-feeding which resulted in brood reduction were largely responsible for keeping the parents in good enough condition to care for the surviving nestlings. Therefore, this study clearly demonstrates that brood reduction can operate through the differential allocation of food between parent and young in a way that can have adaptive consequences for the survival of parents and their young. Correspondence to: T.L.F. Martins     

Age-related foetal sex ratio bias in Iberian red deer (<Emphasis Type="Italic">Cervus elaphus hispanicus</Emphasis>): are male calves too expensive for growing mothers?

Several theories predict offspring biases towards males or females with increasing reproductive resources of the mother to maximize reproductive returns by offspring, or as a result of prohibitive cost of the most expensive sex for young mothers or those in poor condition. This study examines foetus sex of 221 harvested hinds in a food-supplemented game estate for 10 years, according to hind age class (yearlings, subadults or adults), precise age, body mass and condition, and jaw length. A logistic model showed that hinds had a greater probability of bearing a male foetus with increasing age class, but not with any other variable. The greatest bias was found in yearling hinds. After controlling for age class and mass, jaw length was smaller in pregnant compared to non-pregnant yearlings and subadults, which suggests a trade-off between reproduction and growth. The bias towards females in yearlings increased as gestation proceeded, which suggests that the bias might be a result of selective abortion of male foetuses. Although results do not exclude an investment in males to increase number of grand-offspring, they suggest that young hinds may produce daughters as a trade-off between low energetic-cost offspring and their need to grow.Communicated by S. Krackow