Study of the evolution and degradation products of ciprofloxacin and oxolinic acid in river water samples by HPLC-UV/MS/MS-MS

The results of a degradation study of the (fluoro)quinolone antibiotics ciprofloxacin and oxolinic acid in river water samples are presented in this paper. The decomposition of these compounds at ambient temperature was monitored during five months by HPLC-UV, and two consecutive degradation processes (photo- and bio/chemical-degradation) were observed in both cases although with different degradation rates. Ciprofloxacin was completely degraded after 3 months whereas 80% of oxolinic acid remained unaltered after five months of storage. The analysis of the degradation compounds formed was carried out using MS and tandem MS-MS, allowing the identification of four new ciprofloxacin transformation products not previously described in the literature. Possible degradation pathways for this antibiotic in river water are proposed.     

Potential responses of terrestrial biodiversity in Southern Africa to anthropogenic climate change

Key studies supported by species-level data collection have provided early indications of the potential implications of unmitigated change for the ecosystems and biodiversity of southern Africa. These suggest a significant threat to biodiversity, both from changing bioclimatic suitability and changing atmospheric CO₂ level that seems to affect the competitive balance between woody and herbaceous plants in the dominant savanna biome of this region. Modeling efforts suggest significant implications of unmitigated climate change for this region, but assumptions underpinning methods such as bioclimatic modeling must be recognized, some of which might lead to over estimates of the rate and extent of the potential impacts. General trends and level of coincidence between various types of studies do support a high degree of concern for a substantial portion of southern African biodiversity under unmitigated climate-change scenarios. The most significant changes in ecosystem structure (both increases and decreases in woody plant cover), and associated faunal diversity changes, are projected in the dominant savanna vegetation type in this region, while the most significant biodiversity loss is projected for the winter rainfall region. Follow-up work to detect early signs of climate change identify regions of high- and low-potential impacts, and experimental work to test some important hypotheses relating to the future evolution of climate-change impacts across the region are very few and urgently required.     

Ensuring effectiveness of information to influence household behaviour

The behaviour of household members has a significant impact on the resulting energy consumption of a household. Studies show that within the same buildings with the same installations, energy consumption can be reduced by an average of 37% by a more economical behaviour. There exists therefore, a large potential to reduce the demand by influencing behaviour.The question remains how this potential can be addressed. VITO conducted, in collaboration with the Catholic University of Louvain-la-Neuve, the SEREC-project. This project investigated the socio-economic factors influencing residential energy consumption; furthermore, in the larger framework different tools have been developed. Several were tested and evaluated in a number of dwellings in this research. They address both energy consumption for heating as well as electricity consumption. The tools are completely different, but all were designed to help make householders aware of their energy-related behaviour and to provide recommendations on energy saving measures. For each case, potential changes in habits were followed-up. The observed range is quite large, as full scale audits of every dwelling were performed as general comparisons of annual consumption were made.To gain more insight into the effectiveness of the tools, several families participated in in-depth sociological interviews. The overall results show the strengths and weaknesses of the different tools. More generally, the results reveal some of the key properties of recommendations that are necessary to ensure effectiveness for behavioural change.     

Cytotoxic activity of spark‐decomposed sulfur hexafluoride and analysis of cytotoxic contributions of individual spark decomposition products†

Sulfur hexafluoride decomposed by electrical sparks has been found to by cytotoxic to hamster cells when tested in an in vitro cell survival assay, while SF₆ shows no cytotoxic activity. Chemical analysis of spark‐decomposed SF₆ has identified and quantified the following compounds: SOF₂, SO₂F₂, SF₄, SOF₄, SiF₄, SO₂ and HF. Each of these gases, at concentration ranges expected in spark‐decomposed SF₆, were tested for cytotoxic activity toward hamster cells. Of the gases showing cytotoxic activity, SO₂F₂ and SOF₄ were similar in activity, as were SOF₂ and SF₄, while the behavior of SiF₄ was different from the rest. None of these individual gases, at concentrations expected in spark‐decomposed SF₆, has sufficient cytotoxic activity to account for the cytotoxic effect of spark‐decomposed SF₆ observed in our assay system. A four‐component mixture of some of the gases enumerated above (at concentrations overestimating their abundance in spark‐decomposed SF₆) was much less cytotoxic than the spark‐decomposed SF₆ gas. A mathematical simulation of the cytotoxic activity of a mixture of gases at concentrations found in spark‐decomposed SF₆ was made, assuming independent cytotoxic effects from each component. The simulated cytotoxic effect thus computed was less than that seen in spark‐decomposed SF₆. Since individual components or mixtures of the major decomposition products do not account for the observed biological activity of spark‐decomposed SF₆, this suggests there may be one or more components, present in the spark‐decomposed gas at very low concentrations, which may have a very strong cytotoxic activity.     

Evaluating animal personalities: do observer assessments and experimental tests measure the same thing?

The animal personality literature uses three approaches to assess personality. However, two of these methods, personality ratings and experimentation, have been little compared in captivity and never compared in the wild. We assessed the boldness of wild chacma baboons Papio ursinus using both ratings and experimental methods. Boldness was experimentally assessed when individuals were presented with a novel food item during natural foraging. The boldness of the same individuals was rated on a five-point scale by experienced observers. The ratings and experimental assessments of boldness were found to correlate positively and in a linear fashion. When considered categorically the two approaches showed variable agreement depending on the number of categories assigned and the cut-off criteria adopted. We suggest that the variation between approaches arises because each method captures different aspects of personality; ratings consider personality in absolute terms (using predefined criteria) and multiple contexts, while experimental assessments consider personality in relative terms (using experimental scores relative to the population average) and in limited contexts. We encourage animal personality researchers to consider adopting both methodologies in future studies. We also propose that future studies restrict their analyses to continuous data, since the greatest comparability between methods was found with these data. However, if individuals must be categorised, we suggest that researchers either (a) analyse only those individuals categorised as bold or shy by both ratings and experimental approaches or, if these methods cannot be employed simultaneously, (b) do not use approach-specific criteria but choose a cut-off that can be compared by both approaches.     

RELIABILITY AND ECONOMIC OPTIMIZATION FOR URBAN RETURN FLOWS MANAGEMENT1

ABSTRACT The reduction of the liability of pollution to urban water resources is considered as one of the common goals of all elements of our society. To approach the challenge with a sense of realism the probabilistic nature of the performance of pollution control facilities as well as environmental responses must not be ignored and cannot be eliminated. Reliability is defined herein as the measure of effectiveness for the attainment of water quality managerial goals. The objective of this paper is to develop an optimization model for the determination of the best pollution control policies for each treatment facility in terms of the minimization of total regional cost requirements, the quality control requirements, and the reliability desired. A chance-constrained quadratic programming technique coupled with parametric analysis is utilized as the basic solution approach. A practical problem based on the situation existing in the San Antonio River Basin Region of Texas was used for the illustration of this application. The implications resulting from the sensitivity analysis of this model will be discussed.     

Initial repercussions and hydroelectric developments in the French upper rhone valley: A lesson for predictive scenarios propositions

The authors demonstrate the difficulties inherent in predicting vegetation changes in floodplains affected by hydroelectric developments. The results are based on phytoecological studies in the Rhone River valley between Geneva and Lyon. The study is based in a 200-km stretch of river where the floodplain can attain 10 km in width. Vegetation is described for the area prior to the construction of four dams and compared with the situations 8 yr later. Research methods include systematic sampling of geomorphological, soils, and floristic factors; collection of a data base of spatial information; and large-scale vegetation mapping.     

Intra-storm study of solute chemical composition of overland flow water in two agricultural fields

Few studies have assessed the transport of dissolved nutrients at the field scale under natural rainfall conditions. Hysteresis between dissolved nutrients and discharge behavior can complicate such assessments and this effect has only been examined qualitatively. In this study, we investigated factors contributing to short-term variations of dissolved cation (Ca, Mg, Na, and K) and anion (soluble reactive phosphorus [SRP], NO3, and SO4) concentrations in runoff water and developed a quantitative method to study their hysteretic behavior. Within-storm variations of dissolved nutrient concentrations were determined in two agricultural fields during four natural rainfall events along with discharge, sediment, antecedent soil water conditions, and nutrient contents. For each event, nutrient loads were plotted against discharge during the rising and falling limb of the runoff hydrograph. The resulting hysteresis curves were characterized by an index H, which is the ratio between the integrated areas under the rising and falling curves of the hydrograph. Results showed that nutrient concentrations increased with time during each event. Counterclockwise (H < 1) hysteresis, occurring when the falling limb had larger loads, was found when soils were initially dry whereas clockwise hysteresis (H > 1) was associated with prior wet soil conditions. Two hypotheses are suggested to explain these variations. First, suspended sediments could have acted as a sink for dissolved nutrients and the sensitivity of nutrients to hydrological conditions was determined by their preferential sorption on these sediments. Second, movement of nutrients into runoff occurred more readily as soils became wetter during an event.     

Patch leaving decision rules in parasitoids: do they use sequential decisional sampling?

Within the framework of optimal foraging theory, models assume that parasitoid insects are able to evaluate the quality of the patch in which they are currently searching for hosts and the travel time between patches. They can adjust their residence time in consequence. Simple and more realistic decision mechanisms that induce behavior compatible with the predictions of these models have been proposed for a number of species. Most of these decision mechanisms only take into account the presence of unparasitized hosts. Here, we studied the consequences for leaving patches containing different proportions of unparasitized and parasitized hosts. We support the hypothesis that parasitoids sample their environment and we propose a binomial sequential model, based on the type of host encountered (unparasitized or parasitized) instead of on the time spent in a patch, to explain the giving-up behavior of a parasitoid in a patch. A motivational incremental/decremental stochastic process is proposed to explain a possible mechanism of the apparent sampling scheme followed by the insect. The empirical data support the hypothesis of a sequential, decisional, binomial sampling scheme performed with a limited memory. This memory is, in fact, more an effect of habituation than the "true memory" of the parasitoid. The theoretical model was applied to real data obtained with an encyrtid parasitoid. These data were also compared to realizations of the incremental/decremental process.     

Effects of Motorized Tourboats on the Behavior of Nonbreeding American Flamingos in Yucatan, Mexico

We assessed the effect of motorized tourboats on the behavior of nonbreeding American flamingos (  Phoenicopterus ruber ruber) in the Celestún Estuary, a Special Biosphere Reserve in Yucatán, Mexico, from November 1994 through February 1995. We measured these effects by comparing activity budgets between flocks of flamingos disturbed and undisturbed by tourboats. Disturbance reduced feeding time from 40% before disturbance to 24% after, a 40% loss. Boat disturbance increased alert behavior by 400%. Tourboats averaged 13 per day and caused a disturbance 75% of the time or 3.3 hours per day. Potential loss of feeding time for individuals was estimated at 13% but is likely much higher on days with excessive numbers of tourboats. Flamingos returned to normal feeding rates (40%) within 20 minutes after disturbance. Most tourists (52%) were from Mexico, followed by Germany (14%), and 88% of Mexican visitors were willing to pay an entrance fee to the Celestún Reserve. Conservation efforts should focus on education of tourboat operators to reduce disturbance to flamingos, education of tourists through a visitor's center and brochures produced in Spanish and English, and expanded involvement of local people.