A stratified model for the assessment of meteorologically adjusted trends of surface ozone

We consider the problem of assessing long-term trends of ozone concentrations measured on a single site located in an urban area. Among the many methods proposed in the literature to eliminate the confounding effect of changing weather conditions, we employ a stratification of daily maxima based on regression trees. Within each stratum conditional independence and Weilbull distribution are assumed for maxima. Long-term trend is defined non-parametrically by the sequence of yearly medians. Models are estimated following the Bayesian approach. The alternative assumptions of common and stratum specific trends are compared and a model with common trend for all strata is selected for the analyzed real dataset. The conditional independence assumption is checked by the comparison with a model including an autoregressive component.     

Aggregation of Dynamic Systems and the Existence of a Regeneration Function

In environmental economics, complex ecosystems are often represented by low-dimensional models. The question of whether the results of these models can be applied to a more complex reality leads to the investigation of an aggregation problem in a nonlinear dynamic setting. We show that restrictive assumptions are needed for aggregation and that the low-dimensional model has to be linear. On the basis of these results, we argue that the aggregation of complex ecosystems is often oversimplifying and that substantial gains can be expected from the use of more complex models.     

Predominance of alcohol and illicit drugs among traffic accidents fatalities in an urban area of Brazil

Objective: The objective of this study was to determine the prevalence of alcohol and illicit drug use among victims of fatal traffic accidents in the Metropolitan Region of Vitória, Brazil, during the period 2011–2012.

Methods: Blood samples were collected and analyzed for the presence of drugs from 391 deceased victims of traffic crashes that occurred in the Metropolitan Region of Vitória, Brazil. The victims included drivers, passengers, and pedestrians. Sociodemographic variables such as age, gender, day of the week, and period of the year in which the accidents occurred were recorded. The analyses were performed by a gas chromatography–flame ionization method for alcohol and by a gas chromatography–mass spectrometry for amphetamines, cocaine, and cannabis.

Results: The results showed that 44.8% (n = 175) of all cases were positive for alcohol and/or illicit drugs. The detection of alcohol and/or drugs was more frequent in young males, aged 17 to 34, whose samples were positive in 46.8% of cases. Small differences among drivers, passengers, and pedestrians were observed (drivers = 45.9%, passengers = 46.4%, and pedestrians = 45.6%). In general, the most prevalent drug was alcohol, with 141 positive cases (36.1%), followed by cocaine, with 47 positive cases (12%). Amphetamines and cannabis had positivity rates of 4.1 and 4.3%, with 16 and 17 positive cases, respectively. The combined use of alcohol and other drugs was found in 36 cases (9.2%). Crack cocaine use was observed in 27.7% of the positive cases for cocaine.

Conclusions: For the effective reduction of traffic accidents related to driving under influence of drugs (DUID), we suggest the intensification of enforcement actions against the use of alcohol by drivers, the definition of which illicit drugs should be surveyed, as well the cutoff values, the promotion of changing legislation to oblige drivers to provide samples for toxicological testing, and the establishment of public information programs and specific actions aimed at young drivers to promote behavioral changes.     

Influence of parasitism on the use of small terrestrial rodents in environmental pollution monitoring

Bioaccumulation of cadmium, chromium, copper, manganese, nickel, lead and zinc in small terrestrial rodents – voles and their cestode parasite Paranoplocephala dentata was studied. Contents of Pb, Mn, Ni and Zn in the parasite were found to be higher than in the kidney and liver of the parasitized animals. Lead level in the cestode was 37 fold higher than in the liver of the infected rodents. Bioaccumulation factors of zinc, nickel and manganese in the cestode are mostly in the range from 2 to 4.5. Considering the different contents of manganese and zinc in livers of non-parasitized and parasitized rodents, kidney tissue was found to be more reliable than liver as an indicator of environmental pollution by manganese and zinc; the kidneys of parasitized animals showed no significant change in the concentrations of those elements that are accumulated in the cestode.     

Reevaluation of the sex pheromone of the lesser date moth, Batrachedra amydraula, using autosampling SPME-GC/MS and field bioassays

In a previous study of the sex pheromone of the lesser date moth, Batrachedra amydraula, using laboratory females, (Z4,Z7)-4,7-decadien-1-yl acetate, Z4-decen-1-yl acetate, Z5-decen-1-yl acetate and decyl acetate were identified by sequential SPME-GC/MS analysis. Traces of Z5-decen-1-ol were detected only in airborne collections. Concomitant field tests and re-evaluation of the composition of the sex pheromone of B. amydraula with feral female moths, using an improved sequential SPME-GC/MS procedure revealed a complex mixture of candidate pheromonal compounds. The same unsaturated acetates and the corresponding alcohols: (Z4,Z7)-4,7-decadien-1-ol, Z4-decen-1-ol, Z5-decen-1-ol were positively identified. In addition, the corresponding aldehydes, octanol and octyl acetate were also detected. All compounds were found to be released in a circadian rhythm, in a narrow time window of 2 h, approximately 1 h before sunrise. Comprehensive field bioassays indicated that the optimal attractive blend is a three-component mixture of (Z4,Z7)-4,7-decadien-1-yl acetate, Z5-decen-1-yl acetate and Z5-decen-1-ol in a ratio of 1:2:2. This blend gave about fivefold higher trap catch of B. amydraula males as compared to the previously published binary blend of (Z4,Z7)-4,7-decadien-1-yl acetate and Z5-decen-1-yl acetate in a ratio of 1:2. The alcohol Z5-decen-1-ol is an essential synergistic component of the sex pheromone of B. amydraula. All other identified compounds are inert, being neither synergists nor inhibitors of the pheromone. The optimal pheromone blend will be a useful tool in monitoring and control of B. amydraula, which is a serious pest of date plantations throughout the Middle East and northern Africa.     

Retrospective analysis of spatial and temporal variability of chlorophyll-a in the Curonian Lagoon

The Curonian Lagoon, the largest in Europe (total surface area 1584?km²), is located in the southern part of the Baltic Sea, from which it is separated by a narrow sand bar and to which it is connected by the Klaipeda Straits. It is characterised by shallow eutrophic waters (mean depth 3.8?m) with average low salinity (<5??) due to the nutrient-rich freshwaters discharged by the river Nemunas. Cyanobacteria blooms, including species producing toxic metabolites, have been a frequent phenomenon in summer. In this study a series of MERIS Full Resolution (FR) satellite images acquired between 2004 and 2009 during summer periods were used to assess the temporal evolution and spatial variability of the lagoon water quality in terms of chlorophyll-a. The models/algorithms were calibrated/validated with field data collected in 2009, based on in situ radiometric (remote sensing reflectance -Rrs-) and limnological (chlorophyll-a concentrations -chl-a-) measurements. The chl-a concentrations were estimated by developing a semi-empirical band ratio (Rrs(708)/Rrs(664)) equation applied to MERIS images after correction for atmospheric effects with the 6S code. Results from this study suggest elevated spatial and temporal variability of chl-a. Spatial variability probably arises from the mosaic of situations within the Curonian lagoon in terms of bottom sediment features, nutrient availability in the water column, water depth and hydrodynamics. Temporal variability is probably linked to complex and interplaying metereological and environmental constraints such as the length of the ice cover period, average water temperatures, wind-induced sediment re-suspension, the pattern of precipitations and river-associated nutrient transport to the lagoon. This study stresses the importance of remote sensing as a valid tool for long-term whole ecosystem studies. The preliminary results need more through analyses and intersection with other environmental data in order to better comprehend algal bloom determinants in complex and extremely dynamic systems such as coastal lagoons.     

Spatio-temporal distribution and migration of adult male loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea: further evidence of the importance of neritic habitats off North Africa

Ten adult male loggerhead sea turtles, captured by trawlers or dip nets, were satellite-tracked from a neritic foraging ground in the Mediterranean in order to investigate adult spatio-temporal distribution and breeding migration. Five individuals migrated to potential breeding sites in Libya and one to Greece. The results complement previous studies and show that: (1) the Tunisian shelf may be more important for turtles from Libyan rookeries than previously thought; (2) male tracks corroborate a conservation hotspot previously identified for juveniles; (3) the north African coast represents a preferred migratory corridor, unless open sea routes are more direct; (4) adult males may exhibit high fidelity to relatively small areas, without evident seasonal differences; (5) adults home ranges were smaller and more neritic than juveniles frequenting the same area; (6) males may frequent multiple courtship areas; (7) the average remigration interval of males frequenting this region is longer than 1 year.     

Surrogate compounds for dioxins in incineration. A review

Dioxins, formed in any combustion process where carbon, oxygen and chlorine are present, are a subject of major interest due to their toxicity. Their measurement is very expensive and time consuming. In order to optimize the combustion process, on-line measurements of pollutants must be done. The use of surrogate compounds instead of dioxins seems to be a convenient method to overcome the aforementioned drawback. This work is a review of the literature dedicated to the possible surrogate compounds for dioxins; the relationships found were systematized and, in some cases, the available experimental data were used and original correlations were found. Correlation of surrogate compounds was found to be: incinerator, feedstock, process and sample point location specific. Amongst the possible surrogates, chlorobenzenes show real possibilities to be good indicators for toxic equivalent factors.     

Behavioral and life-history evidence for interspecific competition in the larvae of two heliconian butterflies

Interspecific competition in herbivorous insects remains a controversial issue. To date, many studied systems have not met assumptions of the traditional competition theory, and a new paradigm has been emerging. We examined the behavioral and life-history consequences of common host plant use of Heliconius erato and Dryas iulia (Nymphalidae) in relation to Passiflora suberosa (Passifloraceae). Larvae of the former use the apical portion of this host; the latter is presumably able to explore all plant parts. We assessed host use pattern in relation to leaf age, when reared either alone (D. iulia) or together (D. iulia and H. erato). Larval feeding choice tests with respect to leaf age were performed, and performance was recorded. Observations were made to assess antagonistic behavior of H. erato and D. iulia towards each other, if any. Similarly to H. erato, D. iulia fed on the young leaves significantly more than the mature ones; larvae were not induced to prefer mature leaves. First instars of H. erato used only the apical parts of P. suberosa and displayed aggressive behavior towards D. iulia, which moved to the lower shoot portions. Larval mortality and development time of both species significantly increased when reared together; such performance costs were more pronounced in D. iulia than H. erato. Our study gathers evidences that use of P. suberosa by these heliconian butterflies represent a case of competitive exclusion resulting in niche differentiation, where costs are higher for D. iulia than H. erato.