Stream regulation in Argentina,including the superior Paraná and Paraguay rivers

Argentine water resources are located in three hydrologically contrasting regions: the so-called Del Plata basin, the Arid Central Andean area, and Patagonia. About 150 dams and impounding reservoirs that exceed a capacity of 150 × 103 m³, have been built. Most limnological studies of regulated rivers have been conducted recently. In the Del Plata basin, Argentine dams are scarce, although many have been built or are projected upstream, mainly in Brazil. The ecological problems of the reservoirs are related to decomposition of inundated terrestrial vegetation; algae blooms, dissolved oxygen depletion phenomena, eutrophication, impaired fish migrations, overproduction of water hyacinth Eichhornia spp., and schistosomiasis. The importance of examining the influence of the projected middle Paraná dams on downstream sediment regimes, especially as it affects the delta, is emphasized. In the Arid or Central Andean region, the main development of the Grande-Tercero rivers includes dams, reservoirs, and the operation of a nuclear power plant. One of the most important effects will be a slight increase in the water temperature of the Rio Tercero reservoir as a consequence of water use in the cooling system of the nuclear power plant. In the Patagonian region, the main dams are those built and projected for the Colorado and Negro basins. In the Negro basin studies are being carried out mainly in the Ramos Mexia Reservoir, on different aspects of zooplankton and phytoplankton, benthos, and fishes. Commercial fishing is not permitted and fishing is based mainly on the introduced salmonids which show symptoms of undernourishment because of a lack of forage fishes. Indigenous fishes have been decimated by the introduced salmonids. Although studies have been conducted in several areas, much work remains to be done in relation to the environmental effects of dams on streams in Argentina. Results from ecological studies are still insufficient to solve the multiple problems associated with them, such as climatic influences, retention of suspended solids, deforestation, schistosomiasis and other aquatic diseases, pollution, eutrophication, fish-ways and fish migrations, accumulations of the water-hyacinth, salt and nutrient regimes, and siltation. Even partial solutions to these problems will require an ensemble of urgent measures to assure the maximum benefits with minor risks and ecological costs.     

Bayesian eggs and Bayesian omelettes: Reply to Stern (2005).

In this response to Stern's (2005) (see reocord 2005-16136-010) discussion of Klugkist, Laudy, and Hoijtink (2005), model inference based on posterior probabilities on the parameter space is discussed. Furthermore, the authors respond to Stern's example in which all possible orderings are included via a short discussion of exploratory versus theory-based modeling. Finally, the authors show that the Bayesian approach is flexible and can deal with many types of constraints. This is illustrated using a model with constraints on the differences between means. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Competency assessment models.

This article describes characteristics of alternative assessment models deployed in the measurement of professional competencies across the professional life span based on the work of the American Psychological Association Task Force on the Assessment of Competence in Professional Psychology. Assessments of knowledge, decision making, performance and personal attributes, as well as integrated practice-based skills and tasks are described and compared on the basis of their validity, feasibility and practicality, fidelity, and relevance at difference stages of professional development. It is acknowledged that no single assessment can evaluate all competencies and that assessments can be combined in complementary ways. Assessments deployed in the nursing, dental, and medical professions are reviewed and contrasted with current practices in psychology. At the licensure level, differences in the assessments deployed among the 4 healthcare professions are described, and their candidate fees and number of candidates assessed annually are documented. Ideas for developing new assessments in psychology are discussed on the basis of the needs and financial resources available to psychology and the experiences of other healthcare professions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Age and Awareness on Eyeblink Conditional Discrimination Learning.

The present study aimed to assess the effects of aging and awareness on conditional discrimination learning within an eyeblink conditioning procedure by using a consecutive age-groups design (20-35 years, 36-50 years, 51-65 years, 66-80 years). Increasing age was associated with a decline in overall eyeblink conditioned response (CR) frequency and a deficit in conditional discrimination learning in the 2 older groups. Awareness of stimulus contingencies affected discrimination performance but not overall CR rates in younger subjects. Older subjects did not achieve eyeblink conditional discrimination learning, regardless of awareness. Discrimination performance correlated with measures of declarative memory. The pattern of results is discussed with respect to the involvement of hippocampal-cerebellar interactions and awareness in the mediation of age-related conditioning changes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anthocyanin composition of Tempranillo, Garnacha and Cabernet Sauvignon grapes from high- and low-quality vineyards over two years

The anthocyanin composition of Tempranillo, Garnacha and Cabernet Sauvignon grapes over two vintages was studied. Samples were obtained during berry ripening from two vineyards that differed by producing fruit of high and low quality. The proportions of the individual compounds remained practically constant within a single vineyard along the sampling period, the changes in the anthocyanin composition being principally quantitative. Different multivariate statistical methods showed that the anthocyanin profile was primarily determined by variety. This genetic dependence was particularly verified when the sums of the non-acylated glucosides, the acetates and the p-coumaryl derivatives, were analysed. The mean relative content corresponding to these three anthocyanin fractions was always the same within each variety, independently either of the vineyard or the vintage year considered. Relating to the individual compounds, several permanent qualitative differences between vineyards in each variety were also found, although the difference in the total anthocyanin concentration was always much higher.     

Two novel betaine derivatives from Kancolla seeds (Chenopodiaceae)

Analysis of the polar extracts from kancolla seeds led to the isolation of five betaines: glycine betaine, trigonelline, trigonelline methylester, trigonelline glucosylester and 3-carboxy-1-(2-sulfoethyl)-pyridinium, the last two of which have not previously been reported in the literature. All structures were elucidated from spectroscopic [NMR (¹H, ¹³C, COSY, HOHAHA, HMQC, HMBC)] and mass spectrometric data (ESI-MS).     

Corrosion behavior of a superduplex stainless steel in chloride aqueous solution

Super duplex stainless steels (SDSS) have been widely used as structural materials for chemical plants (especially in those engaged in phosphoric acid production), in the hydrometallurgy industries, and as materials for offshore applications due to their excellent corrosion resistance in chloride environments, compared with other commercial types of ferritic stainless steels. These alloys also possess superior weldability and better mechanical properties than austenitic stainless steels. However, due to their two-phase structure, the nature of which is very dependent on their composition and thermal history, the behavior of SDSS regarding localized corrosion appears difficult to predict, especially in chloride environments. To improve their final properties, the effect of the partition of the alloying elements between the two phases, and the composition and microstructure of each phase are the key to understanding the localized corrosion phenomena of SDSS. This paper concerns the effects of the SDSS microstructure and heat treatment on the SDSS corrosion resistance in aqueous solutions, containing different amounts of NaCl at room temperature.     

Zinc porphyrin with phenoxy-bridged pentacoordinate bis(8-hydroxyquinaldinate)gallium lateral pendants: synthesis and photophysical characterization

This communication reports the synthesis of polymetallic species formed by a zinc-tetraphenolporphyrinate core (ZnTPP(OH)₄, 1) and peripheral gallium-quinaldinate fragments. The photophysical analysis of 1 and of the model compound , R, shows an appreciable overlap between the absorption spectra of 1 and the emission spectra of R, suggesting the presence of a donor–acceptor energy-transfer process. Contrarily, the obtained results indicated that energy transfer does not occur, hence these polymetallic complexes work as double emitting species, for which the colour of luminescence depends on the excitation energy.     

SYBR-Green real-time PCR approach for the detection and quantification of pig DNA in feedstuffs

A real-time polymerase chain reaction assay using primers targeting the porcine-specific mitochondrial 12S rRNA gene and universal eukaryotic primers amplifying a conserved fragment of the nuclear 18S rRNA gene has been developed for the detection and quantification of porcine DNA in food and feedstuffs. The 18S rRNA primers were used as endogenous control for the total content of PCR-amplifiable DNA in the sample. The assay was tested on DNA extracted from raw and heat-treated binary mixtures of porcine tissues in a plant matrix, and on DNA extracted from reference feedstuff samples. Analysis of experimental mixtures demonstrated the suitability of the assay for the detection and quantification of porcine DNA in mixtures containing as little as 0.1%.