235 resultados para Oligo-hidrâmnio


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Array-CGH enables the detection of submicroscopic chromosomal deletions and duplications and leads to an accurate delineation of the imbalances, raising the possibility of correlating genotype to phenotype and mapping minimal critical regions associated with particular patterns of clinical features. We report here on four patients sharing common clinical features (psychomotor retardation, coarse facies and ocular anomalies), with proximal 5q deletions identified by oligo array-CGH. The deletions range from 5.75 to 17.26-Mb in size and occurred de novo. A common 2.63-Mb region between the deletions described here can be defined in 5q12.1 (59,390,122-62,021,754 bp bp from 5pter, hg18) and includes 12 genes. Among them, KIF2A, which encodes a kinesin superfamily protein, is a particularly interesting candidate for the phenotype, as it suppresses the growth of axonal collateral branches and is involved in normal brain development. Ocular defects, albeit unspecific, seem to be common in the 5q12.1 deletion. Identification of additional cases of deletions involving the 5q12.1 region will allow more accurate genotype-phenotype correlations. (C) 2011 Wiley-Liss, Inc.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Aplasia of the mullerian ducts leads to absence of the uterine corpus, uterine cervix, and upper (superior) vagina. Patients with mullerian aplasia (MA) often exhibit additional clinical features such as renal, vertebral and cardiac defects. A number of different syndromes have been associated with MA, and in most cases its aetiology remains poorly understood. Objective and methods: 14 syndromic patients with MA and 46, XX G-banded karyotype were screened for DNA copy number changes by similar to 1 Mb whole genome bacterial artificial chromosome (BAC) array based comparative genomic hybridisation (CGH). The detected alterations were validated by an independent method and further mapped by high resolution oligo-arrays. Results: Submicroscopic genomic imbalances affecting the 1q21.1, 17q12, 22q11.21, and Xq21.31 chromosome regions were detected in four probands. Presence of the alterations in the normal mother of one patient suggests incomplete penetrance and/or variable expressivity. Conclusion: 4 of the 14 patients (29%) were found to have cryptic genomic alterations. The imbalances on 22q11.21 support recent findings by us and others that alterations in this chromosome region may result in impairment of mullerian duct development. The remaining imbalances indicate involvement of previously unknown chromosome regions in MA, and point specifically to LHX1 and KLHL4 as candidate genes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Os sistemas de monitoramento utilizando diatomáceas foram desenvolvidos, em sua maioria, para monitorar os efeitos da poluição orgânica e da eutrofização, adotando como parâmetros de referência a demanda biológica de oxigênio após cinco dias e a concentração de fósforo total. Entretanto, vários fatores naturais têm sido apontados como causadores de variação na composição destas comunidades em rios. Por isso, grandes mudanças estruturais não provam necessariamente a hipótese de que tenha ocorrido algum evento poluidor. Neste contexto, a partir da relação entre a estrutura da comunidade de diatomáceas epilíticas da microbacia do arroio Schmidt, RS, Brasil, mudanças na qualidade da água e alterações físicas do meio, como fluxo, sombreamento ripário, largura e profundidade, objetivou-se colher subsídios para aplicação em programas de manejo e conservação de ecossistemas aquáticos. Durante os meses de janeiro e fevereiro de 2004, foram realizadas quatro excursões científicas a seis estações, totalizando 24 amostragens, para medição das seguintes variáveis: condutividade elétrica, oxigênio dissolvido em saturação, pH, turbidez, demanda biológica de oxigênio em cinco dias (DBO5), demanda química de oxigênio (DQO), fósforo total, nitrato, sólidos totais dissolvidos, sólidos suspensos, sílica, profundidade de submersão do substrato, velocidade da correnteza, diâmetro dos seixos, largura do rio e sombreamento em função da vegetação ripária. Para as análises qualitativas e quantitativas das diatomáceas epilíticas, uma área de 25 cm2 foi raspada de cinco replicatas O material foi oxidado com dicromato de potássio, ácido sulfúrico e clorídrico para confecção de lâminas permanentes. Padrões de distribuição e abundância das espécies foram explorados através da Análise de Espécies Indicadoras e os fatores ambientais responsáveis por esta distribuição foram evidenciados pela Análise de Correspondência Canônica. Os resultados confirmaram a preferência de Cymbella e Encyonema por águas lentas e elevada luminosidade, bem como a adaptabilidade de Cocconeis ao sombreamento. Nitzschia acicularis, Surirella tenera e Planothidium rupestoides revelaram-se indicadoras de ambientes meso-eutróficos. Encyonema perpusilum destacou-se no habitat oligo/β- mesossapróbico, e Sellaphora pupula no sítio de maior concentração de eletrólitos. Pelo cruzamento das respostas das espécies à saturação de oxigênio, DBO5, DQO, condutividade, fósforo total, sólidos totais dissolvidos e turbidez, foi possível estabelecer dois grupos sinalizadores de qualidade: Achnanthes sp. 3, Cocconeis fluviatilis, Navicula angusta, Nitzschia acicularis, Tryblionella victoriae, Pinnularia cf. obscura, Planothidium rupestoides, Sellaphora pupula, Stenopterobia sp. e Surirella tenera, relacionadas com maior impacto antropogênico, e Achnanthes sp. 2, Encyonema perpusilum, Geissleria aikenensis, Luticola goeppertiana, Navicula symmetrica e Nitzschia amphibia, referindo-se a ambientes mais oxigenados, pouco mineralizados e com reduzidos teores de compostos orgânicos. Estas informações também constituem subsídios para estudos paleolimnológicos envolvendo a reconstituição de paleoambientes (e.g. maior abundância de Cymbella indicando ambientes lênticos) e a concentração de paleonutrientes (e.g. Nitzschia acicularis designando períodos de maior eutrofização).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This dissertation deals with sedimentological and structural framework of the siliciclastic rock of the Serra do Martins Formation (FSM) in the Portalegre, Martins and Santana plateau, located to the south of Potiguar Basin, in the southwest and central Rio Grande do Norte state. This formation, regarded as of Oligo-Miocene age based on intrusive relations of the Miocene Macau volcanics, has a still disputable age due to the lack of appropriate bio and/or chronostratigraphic markers. The FSSM deposits crop out along 650 to 750 m high plateau, as a remanescent sedimentary cover directly overlying topographically uplifted pre-cambrian crystalline rocks. During the last decades, these deposits were interpreted according to a Tertiary paleoclimatic evolutionary model, associated to pedogenetic processes. The sedimentological characterization of the FSM was done through a detailed study of its facies, petrography and diagenetic features. The facies study was based on description of field relations, textures and structures, the piling up of the strata and their lateral variations. The FSM was deposited by an anastomosing to coarse-meandering fluvial system, including deposits of lag, cannel-fill, ouver-bank and flood plain. The petrographic composition of the sediments, coupled to their facies and paleocurrent directions, suggest a rather distal sourcearea, to the south of the present plateau. The diagenetic study identified an incipient grain mechanical compaction, pronounced dissolution of the framework, matrix and/or cement components, intense precipitation of kaolinite, silic and, eventually, iron oxides, besides mechanical infiltration of the clays. Most of these events, regarded in the literature as associated to near-surface conditions (eo or telodiagenesis), indicate the FSM sediments were never deeply buried. Topographic relations along longitudinal and transversal sections reaching the Potiguar Basin to the north identified regional dips that allow to discuss stratigraphic correlations between the FSM and the basin formations. The sedimentological features of the different units and the intrusive relations of the Macau volcanics were also considered in these correlations,which support the Oligo-Miocene age previously accepted for the FSM. Concerning the tectonic framework of the FSM, this work investigated the pre-cambrian to cretaceous heritage and the cenozoic deformation, allowing the recognition of pre-, sin and post-FSM structures. The crystalline basement, belonging to the Seridó Belt, displays NE and WNW foliation trends related to the Brasiliano-age ductile shear zones. In this terrain, brittle-ductile and brittle NE- and NW-trending structures, associated with extensional joints filled with pegmatites and quartz veins, are related to an E-W compression by the end of Brasiliano Cycle. The E-W joints and NE-trending fractures were reactivated by N-S to N-S to NW extension during late Jurassic to Cretaceous times, controlling the emplacement of the Rio Ceará-Mirim basic dyke swarm and the opening of the Potiguar rift basin

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Aquatic macrophyte community distribution along the eastern shoreline of the Itaipu Reservoir (one of the South America's largest impoundments) is described in relation to limnological and sedimentological factors. The central body of the reservoir is mesotrophic, while the arms (flooded influent river valleys) along the eastern shore may be oligo-mesotrophic to eutrophic, depending on time of year and sub-catchment characteristics. Macrophyte community composition and species cover were surveyed at 30 sites in four arms, in relation to sediment total P and organic matter; underwater light regime; and water total P and Kjeldahl N concentration, alkalinity, conductivity, depth and pH. Seventeen euhydrophyte and six emergent macrophyte species were recorded. Large stands of Egeria najas dominated the euhydrophyte vegetation, together with free-floating weed species (Pistia stratiotes Linn., Salvinia auriculata Aublet and Eichhornia crassipes (Mart.) Solms.). Canonical Correspondence Analysis of the data showed that two sets of variables were important predictors of aquatic macrophyte community structure. Floating macrophyte assemblage was closely related to concentration of nutrients in both water and sediment, while light penetration was the strongest predictor of submerged species occurrence. Although a large number of potential nuisance species were present, dense growths were restricted to shallower areas of the Itaipu Reservoir, causing localised problems. The possibility of increasing interference by these plants with fisheries, recreational use, transport and hydroelectricity generation suggests a need for continued monitoring of weed distribution and abundance, and investigation of appropriate management measures.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Sequences of the coat protein amino acids of definitive and tentative species of carlaviruses deposited in GenBank were aligned and a region of seven amino acids (GLGVPTE) was found to be conserved. The corresponding nucleotides were aligned, allowing the design of a degenerate primer that together with an oligo dT anti-sense primer, was effective for the detection of three distinct carlavirus species, two transmitted by aphids and one by whitefly. These primers have the advantage that about 940 nt from the 3'-terminus, comprising part of the CP gene (about 60%), the 11 K gene, and the terminal untranslated region can be amplified for sequencing. The fact that this amino acid sequence is conserved in almost all of the sequenced carlaviruses, allows the prediction that this primer pair will be useful as a diagnostic tool for carlavirus species. (C) 2007 Elsevier B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In Brazil, the environmental impacts of fish cage farming in water reservoirs have not been well studied. As this activity is being increasingly practiced, investigations on the impacts of this practice are strongly needed. The goal of this study was to investigate the effects of a small cage tilapia farm on zooplankton assemblages in an oligo/mesotrophic reservoir (Jurumirim Reservoir, Paranapanema River). Zooplankton, limnological variables, and water samples were obtained trimonthly during a year at two sample sites, one was located adjacent to the cage farm and the control area was located one kilometer away from it. Eighteen species were identified and Cladocera was the dominant group. The same species of microcrustaceans were identified at both sites. Among the ecological attributes studied, only evenness showed a tendency towards being higher in the control site. Significant differences between studied variables in the sites were observed only for material in suspension. The results of the study indicate that, during the studied period, the cage farm did not generate detectable changes in the zooplankton assemblages and their ecological attributes. However, small differences in some limnological variables could be an indication of some environmental changes associated with the fish farm system.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Aqueous dispersions of monoolein (MO) with a commercial hydrophobically modified ethyl hydroxyethyl cellulose ether (HMEHEC) have been investigated with respect to the morphologies of the liquid crystalline nanoparticles. Only very low proportions of HMEHEC are accepted in the cubic and lamellar phases of the monoolein-water system. Due to the broad variation of composition and size of the commercial polymer, no other single-phase regions were found in the quasi-ternary system. Interactions of MO with different fractions of the HMEHEC sample induced the formation of lamellar and reversed hexagonal phases, identified from SAXD, polarization microscopy, and cryogenic TEM examinations. In excess water (more than 90 wt %) coarse dispersions are formed more or less spontaneously, containing particles of cubic phase from a size visible by the naked eye to small particles observed by cryoTEM. At high polymer/MO ratios, vesicles were frequently observed, often oligo-lamellar with inter-lamellar connections. After homogenization of the coarse dispersions in a microfluidizer, the large particles disappeared, apparently replaced by smaller cubic particles, often with vesicular attachments on the surfaces, and by vesicles or vesicular particles with a disordered interior. At the largest polymer contents no proper cubic particles were found directly after homogenization but mainly single-walled defected vesicles with a peculiar edgy appearance. During storage for 2 weeks, the dispersed particles changed toward more well-shaped cubic particles, even in dispersions with the highest polymer contents. In some of the samples with low polymer/MO ratio, dispersed particles of the reversed hexagonal type were found. A few of the homogenized samples were freeze-dried and rehydrated. Particles of essentially the same types, but with a less well-developed cubic character, were found after this treatment. © 2007 American Chemical Society.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

To address daily fluctuations in electricity demands, the quantities of water passing through the turbines of hydropower plants can vary significantly (up to fourfold) during a 24-h cycle. This study evaluates the effects of hourly variations in water discharges on the limnological conditions observed in two below-dam river stretches. The study reservoirs, Capivara and Taquaruçu, are the 9th and 10th reservoirs in a cascade of dams in the Paranapanema River in south-east Brazil. The reservoirs exhibit different trophic conditions, water retention times, thermal regimes and spillway positions. Capivara Reservoir is deeper, meso-eutrophic, with a high water retention time and hypolimnetic discharges (32 m) varying between 500 and 1400 m3 s-1. In contrast, Taquaruçu Reservoir is relatively shallow, oligo-mesotrophic, and has a low retention time, with water discharges varying between 500 and 2000 m3 s-1. Its turbine water intake zone also is more superficial (7 m). For two periods of the year, winter and summer, profiles of limnological measurements were developed in the lacustrine (above-dam site) zones of the reservoirs, as well as in the downstream river stretches (below-dam site). In both cases, the sampling was carried out at 4-h intervals over a complete nictemeral cycle. The results demonstrated that the reservoir operating regime (water discharge variations) promoted significant differences in the conditions of the river below the dams, especially for water velocity, turbidity, and nutrient and suspended solids concentrations. The reservoir physical characteristics, including depth, thermal stratification and outlet structure, are also key factors influencing the limnology and water quality at the below-dam sampling sites. In the case of Capivara Reservoir, for example, the low dissolved oxygen concentration (<5.0 mg L-1) in its bottom water layer was transferred to the downstream river stretches during the summer. These study results demonstrated that it is important to continue such investigations as a means of verifying whether or not these high-amplitude/low-frequency variations could negatively affect the downstream river biota. © 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Asia Pty Ltd.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Cladocera assemblages in two cascade reservoirs located in the Paranapanema River in Brazil were studied during two consecutive years. Upstream Chavantes Reservoir is an accumulation system, with a long water retention time, high depth and oligo-mesotrophic status. The downstream Salto Grande Reservoir is a small, run-of-river reservoir, with a short water retention time, shallow depth and meso-eutrophic status. The goal of this study was to determine the inter- and intra-reservoir limnological differences with emphasis on the Cladocerans assemblages. The following questions were posed: (i) what are the seasonal dynamics of the reservoir spatial structures; (ii) how dynamics, seasonally, is the reservoirs spatial structure; and (iii) are the reservoir independent systems? A total of 43 Cladoceran species were identified in this study. Ceriodaphnia silvestrii was the most abundant and frequent species found in Chavantes Reservoir, while C. cornuta was most abundant and frequent in Salto Grande Reservoir. The Cladoceran species richness differed significantly among sampling sites for both reservoirs. In terms of abundance, there was a significant variation among sampling sites and periods for both reservoirs. A cluster analysis indicated a higher similarity among the deeper compartments, and the intermediate river-reservoir zones was grouped with the riverine sampling sites. For the smaller Salto Grande Reservoir, the entrance of a middle size tributary causes major changes in the system. A distinct environment was observed in the river mouth zone of another small tributary, representing a shallow environment with aquatic macrophyte stands. A canonical correlation analysis between environmental variables and Cladoceran abundance explained 75% of the data variability, and a complementary factorial analysis explained 65% of the variability. The spatial compartmentalization of the reservoirs, as well as the particular characteristics of the two study reservoirs, directly influenced the structure of the Cladoceran assemblages. The conditions of the lacustrine (dam) zone of the larger Chavantes Reservoir were reflected in the upstream zone of the smaller downstream Salto Grande Reservoir, highlighting the importance of plankton exportation in reservoir cascade systems. The comparative spatial-temporal analysis indicated conspicuous differences between the two reservoirs, reinforcing the necessity of considering tropical/subtropical reservoirs as complex, multi-compartmental water systems. © 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Asia Pty Ltd.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Orange cakes with addition of inulin and oligofructose to justify a prebiotic claim (minimum of 3 g of fructans in a 60 g serving of cake) were investigated regarding sensory aspects. The sensory profile of cakes with inulin, with inulin/oligofructose and without prebiotics (standard cake) was evaluated using descriptive quantitative analysis. Preference mapping was assessed using multidimensional scaling on data obtained through an acceptability test with a nine-point hedonic scale. The cakes with prebiotics presented greater crust brownness, dough beigeness, hardness and stickiness than the standard cake and lower crumbliness. Principal Component Analysis (69.5 and 10.7% of explanation to the first and second principal components, respectively) showed that crust brownness, dough beigeness, hardness and stickiness contributed to distinguish the cakes with prebiotics from standard cakes. The sensory acceptability was similar for the three cakes and higher when compared to three commercial cakes, but the preference mapping showed that cakes with prebiotics were preferred to commercial cakes. Addition of prebiotics in orange cakes is feasible, based on the sensory results, which may facilitate marketing of this functional food with sensorial qualities equivalent to conventional products. © 2012 Elsevier Ltd.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Planktonic rotifers and cyclopoid copepods were studied in two reservoirs of different trophic states (eutrophic and oligo/mesoeutrophic) in the south of Brazil. During a year, monthly samplings were carried out in three stations in each reservoir. Species richness, frequency and abundance were used to find out useful and indicatives trends of water quality based on these organisms, reinforced by literature data. Species that showed higher differences between reservoirs were chosen. For Rotifera, richness, frequency and abundance of Brachionus were higher in the eutrophic reservoir, but Plationus patulus occurred only in the oligo/mesotrophic reservoir. For copepods, Tropocyclops prasinus dominated in the eutrophic reservoir, but Thermocyclops decipiens, T. minutus, T. inversus and Microcyclops anceps were dominants in the oligo/mesotrophic reservoir. In the canonical correspondence analysis, these species were indicators of the trophic state and were related with chlorophyll-a, total phytoplankton and total phosphorus. The use of these species can be efficient in the studied regions (subtropical/temperate), but comparing with other Brazilian reservoirs of tropical climate, the results could be different. Despite the dominance of T. decipiens over T. minutus, T. inversus has been widely used in Brazil as an indicator of eutrophic waters; in those cases of excessive eutrophication, other species, more rustic, commonly dominate. In the present study, Thermocyclops was dominant in the oligo/mesotrophic reservoir. The dominance of Brachionus for rotifers and Tropocyclops prasinus and Acanthocyclops robustus for copepods were indicative of eutrophic conditions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Geociências e Meio Ambiente - IGCE