Formation of chloroarenes upon gas-phase pyrolysis and slow combustion of benzene-HCl mixtures

Pyrolysis (800–900°C, ca. 5 s) of benzene/HC1 mixtures leads to chlorobenzene (1) even in a reducing environment of H₂ and/or CH₄. With added oxygen, 1 is formed even at 550°C; such slow combustions also yield chlorinated phenols and dibenzofurans.     

Patterns and levels of halogenated volatile compounds in Portuguese surface waters

The present study focused on monitoring the concentration of 14 halogenated volatile organic compounds in surface waters, including sea, estuarine, river water and industrial effluents in order to determine the most ubiquitous compounds and their concentration levels, which were used to establish their geographical and temporal distribution. EPA Method 502, based on purge and trap techniques, was used. In this method volatile organic pollutants are extracted (purged) from the water sample by bubbling inert gas through the aqueous sample. Purged sample components are trapped in a cartridge containing the polymeric sorbent Tenax and, thereafter, the cartridge is heated and backflushed with helium to desorb the trapped sample components directly into a gas chromatograph with electron capture detector (GC-ECD). The linearity range of the method varied from 0.1 to 4 microg L(-1) with a limit of detection at the low microg L(-1) level. The present study consisted of a monthly monitoring of 46 points throughout Portugal, during 14 months. Chloroform was found in 50% of the samples analyzed, its presence being correlated to both agricultural and industrial activities. Other compounds detected were tetrachloroethylene, trichloroethylene, carbon tetrachloride and 1,2,4 trichlorobenzene, which were present in 10-20% of the samples at concentrations up to 18 microg L(-1). 1,1,2,2-Tetrachloroethane and its degradation product 1,1,2-trichloroethane were found in 5% of the samples, the levels of the latter being higher than those of the parent compound in most samples. Sporadic high concentrations of some volatile halogenated organic compounds were attributed to local uses as solvents.     

Study of the biodegradation process of polychlorinated biphenyls in liquid medium and soil by a new isolated aerobic bacterium (Janibacter sp.)

We have isolated and characterised a novel aerobic bacterial strain, designated MS3-02, belonging to the genus Janibacter sp. The capability of this new strain to degrade polychlorinated biphenyls (PCBs) in a commercial mixture (Aroclor 1242) in liquid medium and in soil (sterile and non sterile soil), under laboratory scale, has been evaluated. MS3-02 was isolated from the soil around of an incinerator, located in the east of Madrid (Spain). Gas-chromatographic analysis showed that MS3-02 was able to reduce most peaks observed in the chromatogram between 70% and 100% after seven days of incubation in a culture mineral medium containing yeast extract, but without the addition of biphenyl. The presence of biphenyl in the culture medium decreased the rate of PCB degradation by this bacterium. Comparing the performance of the MS3-02 in liquid culture medium and in soil, degradation was less efficient in sterile soil and still less efficient in non sterile soil. Under the best conditions (sterile soil and 20 weeks of incubation) MS3-02 was able to reduce, between 50% and 100%, nine of the main gas-chromatographic peaks in Aroclor 1242.     

Urban photochemical pollution in the Iberian Peninsula: Lisbon and Barcelona airsheds

Numerical simulations with photochemical transport models were independently performed for two domains situated in the Iberian Peninsula covering the Lisbon and Barcelona airsheds. Although the days chosen for simulation of the two cities are not the same, the synoptic situations in both cases, known as typical summertime situations, were similar, which allowed the development of typical mesoscale circulations, such as sea breezes and mountain and valley winds dominated by the Azores anticyclone. Emission inventories for the two areas were developed. The O3 concentrations recorded in both cities have a similar level. Nevertheless, O(x) values in Barcelona are higher than in Lisbon, which may, at a first glance, indicate an apparently more oxidant atmosphere in Barcelona. Photochemical modeling for the two cities has shown that the behavior of the circulatory patterns in both urban areas is rather different, which mainly has to do with the different strengths of the sea breeze and the topography, inducing an important offshore vertical layered dimension of pollutant transport in Barcelona versus an important inland horizontal transport in Lisbon.     

The importance of crossroads in faecal marking behaviour of the wolves (<Emphasis Type="Italic">Canis lupus</Emphasis>)

For wolves (Canis lupus) scats play an important function in territorial marking behaviour. Depositing scats at strategic sites such as crossroads and on conspicuous substrates probably increases their effectiveness as visual and olfactory marks. It is therefore likely that scats will be deposited, and will accumulate, at particular crossroads where the probability of being detected by other wolves is greatest. To check this hypothesis, a wolf population in NW Spain was studied for two consecutive years, from May 1998 to March 2000, and the spatial distribution of 311 scats detected along roads (both at and away from crossroads) was analysed. This study was conducted over an area of 12,000 ha in Montes do Invernadeiro Natural Park. The results confirm that wolves preferably deposit their scats at crossroads (60.1%) and on conspicuous substrates (72.1%). Significantly more scats were found at intersections with numerous, easily passable roads connecting distant territories. Thus, wolves preferably deposit their faeces at crossroads with high accessibility and driveability. The larger the surface area of the crossroads, the more scats were found. Crossroads are therefore highly strategic points that facilitate the detection of scats.     

Gluconic acid production and phosphate solubilization by the plant growth-promoting bacterium<Emphasis Type="Italic"> Azospirillum</Emphasis> spp.

In vitro gluconic acid formation and phosphate solubilization from sparingly soluble phosphorus sources by two strains of the plant growth-promoting bacteria A. brasilense (Cd and 8-I) and one strain of A. lipoferum JA4 were studied. Strains of A. brasilense were capable of producing gluconic acid when grown in sparingly soluble calcium phosphate medium when their usual fructose carbon source is amended with glucose. At the same time, there is a reduction in pH of the medium and release of soluble phosphate. To a greater extent, gluconic acid production and pH reduction were observed for A. lipoferum JA4. For the three strains, clearing halos were detected on solid medium plates with calcium phosphate. This is the first report of in vitro gluconic acid production and direct phosphate solubilization by A. brasilense and the first report of P solubilization by A. lipoferum. This adds to the very broad spectrum of plant growth-promoting abilities of this genus.     

Correction to: Ecological restoration as a strategy for mitigating and adapting to climate change: lessons and challenges from Brazil

Mitigation and Adaptation Strategies for Global Change - The original version of the article unfortunately contained an error.     

Carbon Storage in Tagus Salt Marsh Sediments

Seasonal variation of above ground and belowground biomass of Spartina maritima and Halimione portulacoides, decomposition rates of belowground detritus in litterbags, and carbon partitioning in plant components and sediments were determined in two Tagus estuary marshes with different environmentalconditions. Total biomass was higher in the saltier marsh from 7,190 to 6,593 g m^-2 dw and belowground component contributed to more than 90%. Litterbag experiment showed that 30 to 50% of carbonis decomposed within a month (decomposition rate from 0.024 to 0.060 d^-1). Slower decomposition in subsequent periods agrees with accumulation of carbon concentration in sediment. Atmospheric carbon annually transferred to the plant belowground biomass is stored more efficiently in sediments of Corroios than Pancas.     

New contributions to the study of common double mutants in the human <Emphasis Type="Italic">LDL</Emphasis> receptor gene

Variations in the gene encoding the low-density lipoprotein receptor (LDLR) can cause familial hypercholesterolemia (FH), one of the most common inherited metabolic disorders in humans. The functional effects of the p.Gln92Glu and p.Asn564His alterations are predicted as benign, but the c.313 + 1G>C and p.Lys799_Phe801del changes are believed to cause disease. Although p.Gln92Glu and c.313 + 1G>C have been observed only in Spain, p.Asn564His and p.Lys799_Phe801del are widespread in Western Europe. In order to estimate the ages (t generations) of these four variants of the gene, to determine their possible origin and to consider the influence of age and selective pressure on their spread, we analyzed 86 healthy individuals and 126 FH patients in Spain. Most of the FH patients investigated carried two of these four LDLR variants simultaneously, while only one patient carried three of them simultaneously. Haplotype analyses were based on five LDLR SNPs: c.81T>C, c.1413G>A, c.1725C>T, c.1959T>C and c.2232G>A. The results suggest that p.Gln92Glu and c.313 + 1G>C arose at about the same time (99 and 103 generations ago, respectively) in the CACTG haplotype and that p.Asn564His and p.Lys799_Phe801del appeared in the CGCCG haplotype and might be slightly more recent variations (92 and 95 generations ago, respectively). Low selective pressures could explain the maintenance of these variants in spite of their ages. The origin of p.Gln92Glu and c.313 + 1G>C appears to be in Spain whereas p.Asn564His and p.Lys799_Phe801del could have been introduced in Spain by Celtic migrations in the seventh to fifth centuries BC.     

Reproducing or dispersing? Using trait based habitat templet models to analyse Orthoptera response to flooding and land use

Habitat templet theory predicts that habitat provides the templet on which evolution shapes species’ multiple traits and thus their characteristic life-history strategies. By analysing entire trait communities (multiple species and traits) in this framework we can enhance our understanding of how species composition changes as environmental constraints vary across the landscape. Here, we study multiple traits of floodplain Orthoptera communities under the influence of two different sources of disturbance, land use and seasonal flooding.The application of two recently developed statistical techniques - qualitative RLQ analysis and subsequent fourth-corner permutation tests - revealed two different life history strategies in Orthoptera as a response to ecological disturbances, resulting from land use management and seasonal flooding. Orthoptera species seem to have developed two complementary strategies: (i) the high active dispersal-low reproduction strategy in intensive land use situations and (ii) the high passive dispersal-high reproduction strategy in areas with high flood disturbance. Disturbance gradients act as trait filters allowing only particular trait combinations i.e. species with particular preadaptations to survive, whereas others go regionally extinct. Reproduction and dispersal capacity seem to be inversely associated with the disturbance gradients. Ovariole number, taken as the measure for reproduction, showed significant phylogenetic signal, which could potentially confound this relationship. Nonetheless, RLQ analyses coupled with fourth-corner permutation tests proved a powerful tool to reveal and disentangle different evolutionary strategies.