872 resultados para Project 2002-053-C : Way Finding in the Built Environment
Resumo:
It is often suggested that competition improves productivity, however, the underlying support for this idea is surprisingly thin. This paper presents a case study examining the e ects of a change in the competitive environment on productivity at the Petrobras, Brazil's state-owned oil company. Petrobras had a legal monopoly on production, re ning, transportation and importation of oil in Brazil until it was removed in 1995. Even though Petrobras continues to have a de facto monopoly, the end of legal monopoly labor productivity growth rate more than doubled. A growth accounting of the industry shows that between 1977 and 1993 output growth rate (and productivity growth rate) is explained by the accumulation of capital, while Total Factor Productivity (TFP) decreased. Between 1994 and 2000 labor productivity growth rate is completely explained by the growth rate of TFP. The results suggest that the threat of competition alone is su cient to improve productivity. They also provide evidence that restricting competition help cause Brazil's depression of the 1980s.
Resumo:
The study proposed to describe sexual development in pelagic stage loggerhead sea turtles Caretta caretta and compare this to hatchlings and adults. It is meant as an ontogenic approach, in order to understand reproductive development and population composition and their dynamics in the pelagic environment. The study focused on the pelagic loggerheads that are found in the waters offshore Madeira Island (Portugal) in the North-eastern Atlantic and use it as a developmental habitat. The innovating character of this work relied on the lack of any description regarding the gonad ontogenesis and reproductive development for the pelagic stage in any of the 7 existing sea turtle species, all of them in danger of extinction. Three methods were used to diagnose the sex of each juvenile individual and asses the level of reproductive development: (1) laparoscopy, (2) gonad biopsy and (3) the assessment of two sex steroids circulating levels, namely testosterone and estradiol. In order to cover all life stages and compare data obtained for the juvenile stage, hatchlings and nesting female adults were sampled at the nearest nesting rookery at Boa Vista Island in the Cape Verde Archipelago. Gonads from dead hatchlings were collected for gonad histology and blood was collected from nesting females for sex steroids assessment. Laparoscopies revealed to be a valid sexing method for the juvenile stage, since gonads are morphologically differentiated at these size classes. Moreover, laparoscopy was validated using gonad histology. Gonad histology of juveniles showed that gonads are already completely differentiated into ovaries or testes at the size classes examined, but development seems to be quiescent. Males present already developed seminiferous tubules with spermatogonia lining the interior of the seminiferous tubule. Female gonads present oocytes at different development stages, but only oocytes up to stage III were observed. The maximum oocyte diameter in each individual correlated with body size, suggesting that reproductive development is an on-going process in juvenile females. The circulating levels of both testosterone and estradiol in juveniles of both sexes were very low and consistently lower than the ones observed in the nesting females from Boa Vista Island. No bimodal distribution was found for any of the sex steroids analysed and thus circulating hormone levels were not a reliable tool for sexing juvenile individuals with a non-invasive technique. The ratio testosterone:estradiol did not show a bimodal distribution either. The levels of testosterone correlated with sea surface temperature. The fact that temperatures observed during this study were below 24ºC might have hindered a differential testosterone pattern between juvenile males and females. Sex ratios for this population were generated according to laparoscopy results and compared among years and size classes. An overall sex ratio of 2 females for each male was found, but they varied among size classes but not among years. Possible causes for the sex ratios observed are discussed. This study is a contribution to our knowledge on the pelagic stage of loggerhead turtles, namely on the population structure regarding sex ratio, which is a vital tool for implementing conservation strategies.
Resumo:
Numerous potentially mutagenic chemicals have been studied mainly because they can cause damaging and inheritable changes in the genetic material. Several tests are commonly used for biomonitoring pollution levels and to evaluate the effects of toxic and mutagenic agents present in the natural environment. This study aimed at assessing the potential of a textile effluent contaminated with azo dyes to induce chromosomal and nuclear aberrations in Allium cepa test systems. A continuous exposure of seeds in samples of the textile effluent in different concentrations was carried out (0.3%, 3%, 10%, and 100%). Cells in interphase and undergoing division were examined to assess the presence of chromosome aberrations, nuclear changes, and micronuclei. Our results revealed a mutagenic effect of the effluent at concentrations of 10% and 100%. At lower concentrations, the effluent (3% and 0.3%) did not induce mutagenic alterations in the test organism A. cepa. These findings are of concern, since cell damage may be transmitted to subsequent generations, possibly affecting the organism as a whole, as well as the local biota exposed to the effluent discharge. If the damage results in cell death, the development of the organism may be affected, which could also lead to its death. © 2008 Elsevier Ltd. All rights reserved.
Resumo:
Includes bibliography
Resumo:
This study is aimed to analyze the thermal comfort in different areas in the city of São Paulo. Two different areas were selected, a densely built (Consolação district) and the other was Fontes do Ipiranga State Park (FISP), an area with only a few buildings and reduced impermeability. A micro-climatic ENVImet was used to simulate the interaction surface-atmosphere in the urban environment. The model resolution is between 0.5 and 10m. This model was developed by Bruse and Fleer (1998) and Bruse (2004). Through the thermal comfort index PMV (predicted mean vote) and MRT (mean radiant temperature) provided by the model, it revealed that the State Park displays PMV values close to comfortable compared to the other studied area. The analysis of thermal comfort index and the Wind flow showed the influence of high buildings in the local climatic environment.
Resumo:
Fish bioassays are valuable tools that can be used to elucidate the toxicological potential of numerous substances that are present in the aquatic environment. In this study, we assessed the antagonistic action of selenium (Se) against the toxicity of mercury (Hg) in fish (Oreochromis niloticus). Six experimental groups with six fish each were defined as follows: (1) control, (2) mercury (HgCl2), (3) sodium selenite (Na2Se4O3), (4) sodium selenate (Na2Se6O4), (5) mercury + sodium selenite (HgCl2 + Na2Se4O3), and (6) mercury + sodium selenate (HgCl2 + Na2Se6O4). Hematological parameters [red blood cells (RBC), white blood cells (WBC), and erythroblasts (ERB)] in combination with cytogenotoxicity biomarkers [nuclear abnormalities (NAs) and micronuclei (MN)] were examined after three, seven, ten, and fourteen days. After 7 days of exposure, cytogenotoxic effects and increased erythroblasts caused by mercury, leukocytosis triggered by mercury + sodium selenite, leukopenia associated with sodium selenate, and anemia triggered by mercury + sodium selenate were observed. Positive correlations that were independent of time were observed between WBC and RBC, ERB and MN, and NA and MN. The results suggest that short-term exposure to chemical contaminants elicited changes in blood parameters and produced cytogenotoxic effects. Moreover, NAs are the primary manifestations of MN formation and should be included in a class characterized as NA only. Lastly, the staining techniques used can be applied to both hematological characterization and the measurement of cytogenotoxicity biomarkers.
Resumo:
Using a first-principles theoretical model the adsorption of a methyl radical on different sized silver nanoparticles is compared to the adsorption of the same radical on model surfaces. Calculations of our structural, dynamical and electronic properties indicated that small changes in the local environment will lead to small changes in infrared (IR) wavenumbers, but in dramatic changes in the IR signal. Our calculations indicate the lower the adsorption site coordination, the higher is the signal strength, suggesting that small changes in the electronic charge distribution will result in bigger changes in the polarizability and hence in the spectroscopic signal intensity. This effect explains, among others, the signal magnification observed for nanoparticles in surface enhanced Raman spectroscopic (SERS) experiments.
Resumo:
In order to assess the epidemiological potential of the Culicidae species in remaining areas of the Brazilian Atlantic Forest, specimens of this family were collected in wild and anthropic environments. A total of 9,403 adult mosquitoes was collected from May, 2009 to June, 2010. The most prevalent among species collected in the wild environment were Anopheles (Kerteszia) cruzii, the Melanoconion section of Culex (Melanoconion), and Aedes serratus, while the most common in the anthropic site were Coquillettidia chrysonotum/albifera, Culex (Culex) Coronator group, and An. (Ker.) cruzii. Mosquito richness was similar between environments, although the abundance of individuals from different species varied. When comparing diversity patterns between environments, anthropic sites exhibited higher richness and evenness, suggesting that environmental stress increased the number of favorable niches for culicids, promoting diversity. Increased abundance of opportunistic species in the anthropic environment enhances contact with culicids that transmit vector-borne diseases.
Resumo:
Questa tesi di dottorato tratta il tema delle Tecnologie Appropriate e delle Buone Pratiche per la gestione delle risorse idriche ed il risparmio energetico nell’ambito dell’abitato urbano e rurale. Viene fatta una breve panoramica sulle principali teorie e metodologie che fino ad oggi hanno fatto da linee guida per la progettazione sostenibile e il corretto utilizzo delle risorse. Questa visione d'insieme servirà per esprimere delle valutazioni e trovare dei comuni dominatori per proporre una nuova metodologia d'approccio alla gestione delle risorse con particolare attenzione rivolta alla condizione presente e alla zona d’intervento. Site specific sustainability Approach (S3A). I casi studio: • Un progetto di approvvigionamento idrico e di desalinizzazione delle acque per un’oasi del Sahara marocchino. • Un progetto di ricerca della Columbia University e della NASA legato alla sostenibilità urbana di New York che analizza i benefici apportati dall'installazione di coperture verdi nell'area di Manhattan da un punto di vista della gestione delle risorse idriche, energetiche e delle componenti ambientali. • Un progetto di verde verticale e giardino pensile a Milano. • Un progetto di approvvigionamento idrico sostenibile e gestione del verde per la città di Porto Plata in Repubblica Domenicana. Approfondimenti e sperimentazioni. • E’ stato approfondito il tema della distillazione solare per la dissalazione e potabilizzazione delle acque in zone rurali desertiche ed isolate. • E’ stato progettato e realizzato un prototipo innovativo di distillatore tubolare con collettore solare parabolico. Il prototipo è stato testato nei laboratori della Columbia University di New York. • Sono state approfondite le Khettaras o Qanat, tunnel sotterranei per l’approvvigionamento idrico nelle zone aride. • Infine sono stati approfonditi i benefici apportati dalle coperture a verde (tetti verdi) e dal verde verticale nelle zone urbane dal punto di vista della gestione delle risorse idriche ed il risparmio energetico.
Resumo:
The amyloid precursor protein (APP) is a type I transmembrane glycoprotein, which resembles a cell surface receptor, comprising a large ectodomain, a single spanning transmembrane part and a short C-terminal, cytoplasmic domain. It belongs to a conserved gene family, with over 17 members, including also the two mammalian APP homologues proteins APLP1 and APLP2 („amyloid precursor like proteins“). APP is encoded by 19 exons, of which exons 7, 8, and 15 can be alternatively spliced to produce three major protein isoforms APP770, APP751 and APP695, reflecting the number of amino acids. The neuronal APP695 is the only isoform that lacks a Kunitz Protease Inhibitor (KPI) domain in its extracellular portion whereas the two larger, peripheral APP isoforms, contain the 57-amino-acid KPI insert. rnRecently, research effort has suggested that APP metabolism and function is thought to be influenced by homodimerization and that the oligomerization state of APP could also play a role in the pathology of Alzheimer's disease (AD), by regulating its processing and amyloid beta production. Several independent studies have shown that APP can form homodimers within the cell, driven by motifs present in the extracellular domain, as well as in the juxtamembrane (JM) and transmembrane (TM) regions of the molecule, whereby the exact molecular mechanism and the origin of dimer formation remains elusive. Therefore, we focused in our study on the actual subcellular origin of APP homodimerization within the cell, an underlying mechanism, and a possible impact on dimerization properties of its homologue APLP1. Furthermore, we analyzed homodimerization of various APP isoforms, in particular APP695, APP751 and APP770, which differ in the presence of a Kunitz-type protease inhibitor domain (KPI) in the extracellular region. In order to assess the cellular origin of dimerization under different cellular conditions, we established a mammalian cell culture model-system in CHO-K1 (chinese hamster ovary) cells, stably overexpressing human APP, harboring dilysine based organelle sorting motifs at the very C-terminus [KKAA-Endoplasmic Reticulum (ER); KKFF-Golgi]. In this study we show that APP exists as disulfide-bound, SDS-stable dimers, when it was retained in the ER, unlike when it progressed further to the cis-Golgi, due to the KKFF ER exit determinant. These stable APP complexes were isolated from cells, and analyzed by SDS–polyacrylamide gel electrophoresis under non-reducing conditions, whereas strong denaturing and reducing conditions completely converted those dimers to monomers. Our findings suggested that APP homodimer formation starts early in the secretory pathway and that the unique oxidizing environment of the ER likely promotes intermolecular disulfide bond formation between APP molecules. We particularly visualized APP dimerization employing a variety of biochemical experiments and investigated the origin of its generation by using a Bimolecular Fluorescence Complementation (BiFC) approach with split GFP-APP chimeras. Moreover, using N-terminal deletion constructs, we demonstrate that intermolecular disulfide linkage between cysteine residues, exclusively located in the extracellular E1 domain, represents another mechanism of how an APP sub-fraction can dimerize within the cell. Additionally, mutational studies revealed that cysteines at positions 98 and 105, embedded in the conserved loop region within the E1 domain, are critical for interchain disulfide bond formation. Using a pharmacological treatment approach, we show that once generated in the oxidative environment of the ER, APP dimers remain stably associated during transport, reaching the plasma membrane. In addition, we demonstrate that APP isoforms, encompassing the KPI domain, exhibit a strongly reduced ability to form cis-directed dimers in the ER, whereas trans-directed cell aggregation of Drosophila Schneider (S2)-cells was isoform independent, mediating cell-cell contacts. Thus, suggesting that steric properties of KPI-APP might be the cause for weaker cis-interaction in the ER, compared to APP695. Finally, we provide evidence that APP/APLP1 heterointeractions are likewise initiated in the ER, suggesting a similar mechanism for heterodimerization. Therefore, dynamic alterations of APP between monomeric, homodimeric, and possibly heterodimeric status could at least partially explain some of the variety in the physiological functions of APP.rn
Resumo:
Phenotypes of plants, and thus their ecology and evolution, can be affected by the environmental conditions experienced by their parents, a phenomenon called parental effects or transgenerational plasticity. However, whether such effects are just passive responses or represent a special type of adaptive plasticity remains controversial because of a lack of solid tests of their adaptive significance. Here, we investigated transgenerational effects of different nutrient environments on the productivity, carbon storage and flowering phenology of the perennial plant Plantago lanceolata, and whether these effects are influenced by seasonal variation in the maternal environment. We found that maternal environments significantly affected the offspring phenotype, and that plants consistently produced more biomass and had greater root carbohydrate storage if grown under the same environmental conditions as experienced by their mothers. The observed transgenerational effects were independent of the season in which seeds had matured. We therefore conclude that transgenerational effects on biomass and carbon storage in P. lanceolata are adaptive regardless of the season of seed maturation.
Resumo:
BACKGROUND: The Enterococcus faecium genogroup, referred to as clonal complex 17 (CC17), seems to possess multiple determinants that increase its ability to survive and cause disease in nosocomial environments. METHODS: Using 53 clinical and geographically diverse US E. faecium isolates dating from 1971 to 1994, we determined the multilocus sequence type; the presence of 16 putative virulence genes (hyl(Efm), esp(Efm), and fms genes); resistance to ampicillin (AMP) and vancomycin (VAN); and high-level resistance to gentamicin and streptomycin. RESULTS: Overall, 16 different sequence types (STs), mostly CC17 isolates, were identified in 9 different regions of the United States. The earliest CC17 isolates were part of an outbreak that occurred in 1982 in Richmond, Virginia. The characteristics of CC17 isolates included increases in resistance to AMP, the presence of hyl(Efm) and esp(Efm), emergence of resistance to VAN, and the presence of at least 13 of 14 fms genes. Eight of 41 of the early isolates with resistance to AMP, however, were not in CC17. CONCLUSIONS: Although not all early US AMP isolates were clonally related, E. faecium CC17 isolates have been circulating in the United States since at least 1982 and appear to have progressively acquired additional virulence and antibiotic resistance determinants, perhaps explaining the recent success of this species in the hospital environment.
Resumo:
Here we explore the role of the interplay between host immune response and epithelial-mesenchymal-transition (EMT)-Type tumor-budding on the outcome of pancreatic adenocarcinoma (PDAC).CD4+, CD8+, and FOXP3+T-cells as well as iNOS+ (M1) and CD163+- macrophages (M2) were assessed on multipunch tissue-microarrays containing 120 well-characterized PDACs, precursor lesions (PanINs) and corresponding normal tissue. Counts were normalized for the percentage of tumor/spot and associated with the clinico-pathological features, including peritumoral (PTB) and intratumoral (ITB) EMT-Type tumor-budding and outcome.Increased FOXP3+T-cell-counts and CD163-macrophages and decreased CD8+T-cell-counts were observed in PDACs compared with normal tissues and PanINs (p < 0.0001). Increased peritumoral FOXP3+T-cell-counts correlated significantly with venous invasion, distant metastasis, R1-status, high-grade ITB, PTB and independently with reduced survival. Increased intratumoral FOXP3+T-cells correlated with lymphatic invasion, N1-stage, PTB and marginally with adverse outcome. High peritumoral CD163-counts correlated with venous invasion, PTB and ITB. High intratumoral CD163-counts correlated with higher T-stage and PTB.PDAC-microenvironment displays a tumor-favoring immune-cell composition especially in the immediate environment of the tumor-buds that promotes further growth and indicates a close interaction of the immune response with the EMT-process. Increased peritumoral FOXP3+T-cell density is identified as an independent adverse prognostic factor in PDAC. Patients with phenotypically aggressive PDACs may profit from targeted immunotherapy against FOXP3.
Resumo:
Climate change and anthropogenic pollution are of increasing concern in remote areas such as Antarctica. The evolutionary adaptation of Antarctic notothenioid fish to the cold and stable Southern Ocean led to a low plasticity of their physiological functions, what may limit their capacity to deal with altered temperature regimes and pollution in the Antarctic environment. Using a biochemical approach, we aimed to assess the hepatic biotransformation capacities of Antarctic fish species by determining (i) the activities of ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase (GST), and (ii) the metabolic clearance of benzo(a)pyrene by hepatic S9 supernatants. In addition, we determined the thermal sensitivity of the xenobiotic biotransformation enzymes. We investigated the xenobiotic metabolism of the red-blooded Gobionotothen gibberifrons and Notothenia rossii, the hemoglobin-less Chaenocephalus aceratus and Champsocephalus gunnari, and the rainbow trout Oncorhynchus mykiss as a reference. Our results revealed similar metabolic enzyme activities and metabolic clearance rates between red- and white-blooded Antarctic fish, but significantly lower rates in comparison to rainbow trout. Therefore, bioaccumulation factors for metabolizable lipophilic contaminants may be higher in Antarctic than in temperate fish. Likewise, the thermal adaptive capacities and flexibilities of the EROD and GST activities in Antarctic fish were significantly lower than in rainbow trout. As a consequence, increasing water temperatures in the Southern Ocean will additionally compromise the already low detoxification capacities of Antarctic fish.
Resumo:
The ability to respond plastically to the environment has allowed amphibians to evolve a response to spatial and temporal variation in predation threat (Benard 2004). Embroys exposed to egg predation are expected to hatch out earlier than their conspecifics. Larval predation can induce a suite of phenotypic changes including growing a larger tail area. When presented with cues from both egg and larval predators, embryos are expected to respond to the egg predator by hatching out earlier because the egg predator presents an immediate threat. However, hatching early may be costly in the larval environment in terms of development, morphology, and/or behavior. We created a laboratory experiment in which we exposed clutches of spotted salamander (Ambystoma maculatum) eggs to both egg (caddisfly larvae) and larval (A. opacum) predators to test this hypothesis. We recorded hatching time and stage and took developmental and morphological data of the animals a week after hatching. Larvae were entered into lethal predation trials with a larval predatory sunfish (Lepomis sp.) in order to study behavior. We found that animals exposed to the egg predator cues hatched out earlier and at earlier developmental stages than conspecifics regardless of whether there was a larval predator present. Animals exposed to larval predator cues grew relatively larger tails and survived longer in the lethal predation trials. However the group exposed to both predators showed a cost of early hatching in terms of lower tail area and shorter survival time in predation trials. The morphological and developmental effects measured of hatching plasticity were transient as there were no developmental or morphological differences between the treatment groups at metamorphosis. Hatching plasticity may be transient but it is important to the development and survival of many amphibians.