Picoplankton structure in clear and turbid eutrophic shallow lakes: A seasonal study

AbstractThe relative abundance of the different picoplankton components (eukaryotic picophytoplankton (Peuk), picocyanobacteria (Pcy) and bacterioplankton), and their relationships with the lake conditions were studied in three types of shallow lakes from the Pampa Plain (Argentina) that differ in their optical properties: clear-vegetated, phytoplankton-turbid and inorganic-turbid. All the selected lakes, but one, are characterized by their different alternative steady state (clear-vegetated and phytoplankton-turbid water phases) following the model proposed by Scheffer et al. (1993).Autotrophic and heterotrophic picoplankton abundances were analyzed seasonally in relation to environmental variables. All the lakes presented high concentrations of total nitrogen (TN) (>229μgL−1), total phosphorus (TP) (>46μgL−1) and dissolved organic carbon (DOC) (>13.7mgL−1). Clear-vegetated lakes were characterized by vertical diffuse PAR (photosynthetic active radiation) attenuation coefficient (kdPAR) lower than 11m−1, whereas inorganic-turbid lake always showed values higher than 21.1m−1. The euphotic zone depth (Z1%) was wider in clear-vegetated lakes (40–140cm) and thinner in the inorganic-turbid (10–20cm). The phytoplankton-turbid lakes presented a wide range in the values of these variables (kdPAR: 5.2–35.8m−1; Z1%: 10–90cm). Phytoplankton chlorophyll-a (Chl-a) strongly differed, ranging from 1.6 to 334.6μgL−1. Picophytoplankton was mainly represented by phycocianine-rich (PC-rich) Pcy in all cases, dominating over Peuk algae. The total and relative abundances of eukaryotic picophytoplankton, Pcy and bacterioplankton, as well as the size structure of the phytoplankton community differed among the water bodies. In general, clear-vegetated water bodies exhibited similar abiotic characteristics, picophytoplankton/bacterioplankton ratios, and phytoplankton size structure. Contrarily, no clear trend was identified for the group of turbid lakes. The contrasting results obtained for the importance of the picoplankton components in phytoplankton-turbid shallow lakes evidence that the availability of the energetical and nutrient resources cannot be solely considered to predict their relative importance in this type of shallow lake

AVALIAÇÃO PÓS-CONSTRUÇÃO DE OBRAS PÚBLICAS: CONTRATAÇÃO EM ETAPAS DE EXECUÇÃO

In Brazil, every public institution has autonomy, in compliance with current legislation, to decide the delivery method, according to its experience and team capacity, This paper proposes to evaluate multi prime contracting construction procurement based on a post-construction performance analysis for a Brazilian public university. The results suggest that buildings constructed in one stage have lower productivity and unit cost, when compared to two stage procurement. However, it was noted that the relevance of post-construction evaluation is on improving institution management processes, rather than a construction judgment instrument.En Brasil, cada institución pública tiene autonomía, respetando la legislación vigente, para decidir la forma de contratación, la modalidad de licitación y los mecanismos de inspección para la ejecución de una obra. Este artículo propone evaluar la estrategia de construir una obra pública con dos o más contratos, divididos en etapas de ejecución. Para esto, se realizó un análisis del desempeño de obras terminadas (pos-construcción) de una universidad federal brasileña, utilizando criterios relacionados con el tiempo (productividad y demora) y el costo (costo unitario y sobre-coste). Los resultados sugieren que los trabajos realizados en una etapa tienen una productividad y costo unitario menor en comparación con las construcciones de dos etapas. Sin embargo, se observa que la relevancia de la evaluación pos-construcción está en la posibilidad de mejorar los procesos de gestión de la institución, más que un instrumento de juicio de cada obra.No Brasil, cada instituição pública possui autonomia, respeitando a legislação vigente, para decidir a forma de contratação, a modalidade licitatória e os mecanismos de fiscalização para a execução de uma obra. Este artigo propõe avaliar a estratégia de construção de uma obra pública com dois ou mais contratos, divididos em etapas de execução. Para isto, foi realizada uma análise do desempenho de obras concluídas (pós-construção) de uma universidade federal sul brasileira, com o uso de critérios relacionados a tempo (produtividade e atraso) e custo (custo unitário e sobrecusto). Os resultados sugerem que obras executadas em uma etapa possuem menor produtividade e custo unitário, quando comparadas com construções realizadas em duas etapas. Observa-se, no entanto, que a relevância da avaliação pós-construção está na possibilidade de aprimoramento dos processos gerenciais da instituição, mais do que um instrumento para o julgamento de cada obra.DOI: 10.53706/gep.v.21.613

Post-occupancy evaluation in a medium city of Santa Catarina : perceptions about the users? satisfaction and needs.

Este artigo ? o resultado de uma pesquisa realizada em um conjunto habitacional de baixa renda, na cidade de Chapec?/SC, que visou avaliar o desempenho funcional das edifica??es e investigar o comportamento e o n?vel de satisfa??o das fam?lias. Para tanto, utilizou-se uma abordagem com m?ltiplos m?todos de avalia??o p?s-ocupa??o (APO), quantitativos e qualitativos, como an?lise walkthrough, question?rio e grupo focal. Observou-se que o PMCMV demonstra pouca preocupa??o com a diversidade socioecon?mica e cultural, bem como em atender a perfis fora do padr?o m?dio existente. Sobre a unidade habitacional, percebeu-se pouca funcionalidade, al?m de um n?mero de ambientes e ?rea ?til inferior ? necessidade de boa parte das fam?lias. Todos esses fatores colaboram para um baixo n?vel de satisfa??o dos moradores e uma r?pida obsolesc?ncia da edifica??o. Al?m disso, a compara??o com estudos similares realizados em outras localidades evidenciou a import?ncia da realiza??o de APOs em diversas regi?es do pa?s, gerando um panorama global do tema e divulgando diferen?as referentes ? diversidade cultural e ambiental.This paper is the result of a research carried out in a low income housing complex in the city of Chapec?/SC, which aims to evaluate the functional performance of the buildings and investigate the behavior and level of family satisfaction. For that, an approach was used with multiple methods of post-occupancy evaluation (POE), quantitative and qualitative, such as walkthrough analysis, questionnaire and focus group. The PMCMV shows little concern with socioeconomic and cultural diversity, as well as attending profiles outside the existing average standard. About the housing unit, low levels of functionality was detected, as well as a number of rooms and a living area that was less than the need of most families. All these factors contribute to a low level of satisfaction of the residents and a rapid obsolescence of the building. In addition, the comparison with similar studies carried out in other locations showed the importance of POEs in several regions of the country, generating a global panorama of the theme and disseminating differences regarding cultural and environmental diversity

Salicylsalicylic acid causes less gastroduodenal mucosal damage than enteric-coated aspirin

The gastroduodenal mucosal damage caused by aspirin and nonsteroidal antiinflammatory drugs is a common clinical problem. We compared two medications designed to diminish mucosal damage: enteric-coated aspirin and salicylsalicylic acid (salsalate). Ten healthy volunteers were randomized to receive either 1.5 g salsalate twice a day or 650 mg enteric-coated aspirin four times a day for six days and were then crossed over to the other drug after a one-week medication-free period. Endoscopic inspection of gastroduodenal mucosa was performed at entry and again after six days of drug therapy for each medicine. Mean serum salicylate concentrations taken before the morning drug dose were 11.2 mg/dl for enteric-coated aspirin and 18.1 mg/dl for salsalate. Only one of 10 subjects receiving salsalate developed mild (grade 1) mucosal damage while six of 10 receiving enteric-coated aspirin developed moderate to severe damage (grade 2–3) (P= 0.01 ). Symptoms were mild in both groups. We conclude that salsalate causes less gastroduodenal mucosal damage than enteric-coated aspirin .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44409/1/10620_2005_Article_BF01536056.pd

Omeprazole ameliorates aspirin-induced gastroduodenal injury

Aspirin and nonsteroidal antiinflammatory drugs (NSAIDs) damage the gastroduodenal epithelium by two mechanisms: direct toxic effects and effects related to the depletion of endogenous prostaglandins. The prostaglandin-depleted mucosa has increased suceptibility to luminal aggressive factors, yet the role of acid in the pathogenesis of the NSAID ulcer is controversial. In humans, standard doses of H 2 -receptor antagonists prevent only duodenal injury and provide no protection for the gastric mucosa. It is not known whether more potent suppression of acid can prevent NSAID damage. Twenty healthy volunteers were randomized to a double-blind, placebo-controlled, crossover study to determine if omeprazole, 40 mg/day prevents gastroduodenal injury due to two weeks of aspirin administration (650 mg four times a day). The severity of mucosal injury was quantitated by endoscopy and stratified by a scale from 0 (normal) to 4 (ulcer). Fourteen of the 20 subjects had less gastric injury during cotherapy with omeprazole. All six with no difference received aspirin plus omeprazole in the first treatment period. Omeprazole significantly decreased aspirin-induced gastric mucosal injury ( P <0.001, Wilcoxon signed-rank test). Omeprazole protected 85% of subjects from extensive gastric erosions (often associated with evidence of intraluminal bleeding) or ulceration, whereas 70% of the subjects developed aspirin-induced grades 3 and 4 gastric injury on placebo ( P <0.01 by X 2 ). No subject taking omeprazole developed duodenal injury of any grade, while 50% taking placebo developed erosions and 15% had ulcer ( P <0.001). Medication side effects were mild in the majority of subjects. Heartburn occurred in seven subjects on aspirin and placebo vs one on aspirin and omeprazole ( P <0.01). Salicylate levels were 7.39±4.72 mg/dl (535±340 µmol/liter) in the placebo group and 6.95±4.3 mg/dl (503±311 µmol/liter) in the omeprazole group. We conclude that omeprazole, 40 mg/day eliminates duodenal injury and markedly ameliorates gastric injury due to administration of aspirin 2600 mg/day. Omeprazole prophylaxis of NSAID injury deserves further study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44420/1/10620_2005_Article_BF02090067.pd

Modeling the bloom evolution and carbon flows during SOIREE: Implications for future in situ iron-enrichments in the Southern Ocean

The impact of a mesoscale in situ iron-enrichment experiment (SOIREE) on the planktonic ecosystem and biological pump in the Australasian-Pacific sector of the Southern Ocean was investigated through model simulations over a period of 60-d following an initial iron infusion. For this purpose we used a revised version of the biogeochemical SWAMCO model (Lancelot et al. 2000), which describes the cycling of C, N, P, Si, Fe through aggregated chemical and biological components of the planktonic ecosystem in the high nitrate low chlorophyll (HNLC) waters of the Southern Ocean. Model runs were conducted for both the iron-fertilized waters and the surrounding HNLC waters, using in situ meteorological forcing. Validation was performed by comparing model predictions with observations recorded during the 13-d site occupation of SOIREE. Considerable agreement was found for the magnitude and temporal trends in most chemical and biological variables (the microbial food web excepted). Comparison of simulations run for 13- and 60-d showed that the effects of iron fertilization on the biota were incomplete over the 13-d monitoring of the SOIREE bloom. The model results indicate that after the vessel departed the SOIREE site there were further iron-mediated increases in properties such as phytoplankton biomass, production, export production, and uptake of atmospheric CO2, which peaked 20–30 days after the initial iron infusion. Based on model simulations, the increase in net carbon production at the scale of the fertilized patch (assuming an area of 150 km2) was estimated to 9725 t C by day 60. Much of this production accumulated in the upper ocean, so that the predicted downward export of particulate organic carbon (POC) only represented 22% of the accumulated C in the upper ocean. Further model runs that implemented improved parameterization of diatom sedimentation (i.e. including iron-mediated diatom sinking rate, diatom chain-forming and aggregation) suggested that the downward POC flux predicted by the standard run might have been underestimated by a factor of up to 3. Finally, a sensitivity analysis of the biological response to iron-enrichment at locales with different initial oceanographic conditions (such as mixed-layer depth) or using different iron fertilization strategies (single vs. pulsed additions) was conducted. The outcomes of this analysis offer insights in the design and location of future in situ iron-enrichments.info:eu-repo/semantics/publishe

Multi-objective optimization of the geometry of single-family housing to improve thermal performance

Brazil's current housing deficit exceeds 6 million homes and a demand of 10 million homes for low-income families is expected by 2040. On the other hand, during the last 10 years, approximately 850,000 social housing units have been delivered through the "My House, My Life" Program - (Programa Minha Casa, Minha Vida – PMCMV). Despite these numbers, several studies suggest some problems related to the low quality of the houses. This article aims to investigate the design parameter related to the geometry of social housing in Chapecó/SC, Brazil, which contributes to the achievement of the best thermal performance. Parametric methods and multi-objective optimizations were utilized, two objective-functions were optimized regarding the degree-hours for cooling and heating. The results showed significant improvements, reaching up to 98% during the hot period and 49% during the cold period. Guidelines were defined to assist architects in the early-phases of the social housing design based on the climate of the target region. However, the best design solutions for thermal comfort throughout the year can only be indicated with computational methods