The elaboration of indices to assess biological water quality. A case study

Here we tested the application of a nodal analysis for the elaboration of biotic indices for particular stressing conditions. The work was carried out in an intermittent Mediterranean stream where superficial flow was absent during summer. The river was perturbed by an effluent with high pH, sulphates, nitrates and conductivity. "Summer" and "winter" samples were treated separately. We first identified groups of sites differing in taxonomical composition by cluster analysis. Then we tested whether groups of sites also differed in their abiotic characteristics. In the following step, groups of cooccurring taxa were also identified by cluster analysis. The indicator value of a taxa group was measured by fidelity measurements for site groups. Indicator taxa were incorporated in a water quality table. The biotic index in the water quality table clearly discriminated impacted from reference sites in the two following years and was correlated with the first axis of a correspondence analysis biplot which also discriminated impacted from clean sites. We suggest that nodal analysis can be a reliable technique for the identification of bioindicators and the elaboration of biotic indices.http://www.sciencedirect.com/science/article/B6V73-3SX5H1V-F/1/2ddcd6137e173976c270b458bbb4c99

The elaboration of indices to assess biological water quality. A case study

Here we tested the application of a nodal analysis for the elaboration of biotic indices for particular stressing conditions. The work was carried out in an intermittent Mediterranean stream where superficial flow was absent during summer. The river was perturbed by an effluent with high pH, sulphates, nitrates and conductivity. "Summer" and "winter" samples were treated separately. We first identified groups of sites differing in taxonomical composition by cluster analysis. Then we tested whether groups of sites also differed in their abiotic characteristics. In the following step, groups of cooccurring taxa were also identified by cluster analysis. The indicator value of a taxa group was measured by fidelity measurements for site groups. Indicator taxa were incorporated in a water quality table. The biotic index in the water quality table clearly discriminated impacted from reference sites in the two following years and was correlated with the first axis of a correspondence analysis biplot which also discriminated impacted from clean sites. We suggest that nodal analysis can be a reliable technique for the identification of bioindicators and the elaboration of biotic indices.http://www.sciencedirect.com/science/article/B6V73-3SX5H1V-F/1/2ddcd6137e173976c270b458bbb4c99

Generalised Space-time and Gauge Transformations

We consider the generalised space-time introduced by the author in 2003 in the context of the non-linear realisation of the semi-direct product of E11 and its first fundamental representation. For all the fields we propose gauge transformations which are compatible with the underlying E11 structure. A crucial role is played by the generalised vielbein that the generalised space-time possess. We work out the explicit form of the gauge transformations, at low levels, in four, five and eleven dimensions.Comment: 33 page

Graphene oxide prevents lateral amygdala dysfunctional synaptic plasticity and reverts long lasting anxiety behavior in rats

Engineered small graphene oxide (s-GO) sheets were previously shown to reversibly down-regulate glutamatergic synapses in the hippocampus of juvenile rats, disclosing an unexpected translational potential of these nanomaterials to target selective synapses in vivo. Synapses are anatomical specializations acting in the Central Nervous System (CNS) as functional interfaces among neurons. Dynamic changes in synaptic function, named synaptic plasticity, are crucial to learning and memory. More recently, pathological mechanisms involving dysfunctional synaptic plasticity were implicated in several brain diseases, from dementia to anxiety disorders. Hyper-excitability of glutamatergic neurons in the lateral nucleus of the amygdala complex (LA) is substantially involved in the storage of aversive memory induced by stressful events enabling post-traumatic stress disorder (PTSD). Here we translated in PTSD animal model the ability of s-GO, when stereotaxically administered to hamper LA glutamatergic transmission and to prevent the behavioral response featured in long-term aversive memory. We propose that s-GO, by interference with glutamatergic plasticity, impair LA-dependent memory retrieval related to PTSD

Identification of cell-surface mannans in a virulent Helicobacter pylori strain

With the intent of contributing to a carbohydrate-based vaccine against the gastroduodenal pathogen, Helicobacter pylori, we report here the structure of cell-surface mannans obtained from a virulent strain. Unlike other wild-type strains, this strain was found to express in good quantities this polysaccharide in vitro. Structural analysis revealed a branched mannan formed by a backbone of α-(1→6)-linked mannopyranosyl residues with approximately 80% branching at the O-2 position. The branches were composed of O-2-linked Man residues in both α- and β-configurations: (image) In addition, this strain also expressed cell-surface emblematic H. pylori lipopolysaccharides (LPS) containing partially fucosylated polyLacNAc O-chains. Affinity assays with polymyxin-B and concanavalin A revealed no association between the mannan and the LPS. The described mannans may be implicated in the mediation of host–microbial interactions and immunological modulation.This work was supported by Fundacao para a Ciencia e Tecnologia (FCT) through project Pylori E&LPS POCI/QUI/56393/2004, PhD grant SFRH/BD/19929/2004, by the Natural Sciences and Engineering Research Council of Canada (NSERC), and by the European Network of Research Infrastructures within the 6th Framework Programme of the EC (Contract # RII3-026145, EU-NMR). The authors further thank Dr. Adrien Favier (RALF-NMR facility, Grenoble - France) for conducting NMR experiments

Caracterização do sistema hidráulico e da qualidade da água em granjas de suínos da Região Sul do Brasil nas fases creche, crescimento e terminação.

bitstream/item/58382/1/CUsersPiazzonDocuments247.pdfAcesso em: 13 jun. 2007