107 resultados para masonry walls


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European naturalists explored Brazil in long scientific expeditions and published accounts that make up a rich and still largely untapped historiographic source for the understanding of the history of chemistry. The production of indigo dye, the manufacture of limestone, extraction and purification of saltpeter and the production of salt are discussed. Lime was used to whitewash walls and, mixed with whale oil, as cement to glue stones in buildings of the colonial period. It was prepared by burning seashells in specifically designed ovens. Saltpeter was produced by reacting naturally occurring calcium and magnesium nitrate with potassium-rich wood ashes to yield KNO3. NaCl was obtained by evaporating seawater under the sun. Indigo, a native plant, was cultivated and processed to produce the renowned dye, which was exported to Europe.

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The assembly of a photochemical reactor with six fluorescent lamps, used for photopolymerizations is described. This chamber presents a mobile support, allowing the placement of samples at different heights and a safety lock that interrupts the radiation, if it is opened during operation. The mirrored internal walls avoid the dispersion and non-uniform distribution of light. There is no high heating because the own character of the used lamps. All parts could be purchased in commerce with less than U$ 150,00. This reactor was successfully used for monolithic stationary phase photopolymerization.

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The Letreiro do Quinto rock shelter is located in the rural area of the city of Pedro II, Piauí, Brazil. The sandstone walls of the shelter are covered with prehistoric rupestrian paintings, painted in patterns of yellow and light and dark red hues. The chemical-mineralogical characterization of the prehistoric pigments was made with energy dispersive spectroscopy, scanning electron microscopy, energy dispersive X-ray fluorescence and 57Fe transmission Mössbauer spectroscopy at 110 K. Results confirm the occurrence of hematite- and goethite-rich ochres and also that the pigment layers are indeed made of a mixture of clay minerals mixed with iron oxides.

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The oceanographic work realized during 10 days in the surroundings of the eruptive island of Trindade, 20º30'36" lat. S - 29º19'26" long. W, had as principal aim the determination of the insular plateau, whose knowledge was very insufficient. Thus were established some oceanographic stations and sounding lines were realized by means of an echobathymeter whose responses were initially verified with mechanical soundings obtaneid by means of a Thomson sounder. The insular plateau is very narrow and exhibits a sudden fall between the 100 and 120 m. depth line at 740 m. - 2950 m. from the coast. Its greatest depth is of 108,30 m. and its mean inclination is of 8,12%. The plateau of the island of Trindade is separated from that of the neighbouring group of Martim Yaz by great depths. The bottoms are rocky near the coast, the blocks having been produced by the rupture of the magmatic mass of the island. Further away from the coast, the size of the rocks gradually diminishes up to the fine sand thickness. In the litoral zone there are abundant tufts of living Lithothamnion with a rich associated flora and fauna, which partly covers the rocks themselves. Further off at sea, the spheres of the dead alga with its commensals are cimented together by sedimentation. The spheres are further broken up and become an integrating part of the sand. The results of the physical and chemical analyses of the sand bottoms are shown in tables 2 and 3. The coast is either of abrupt rocky walls falling down to sea level, or of shores, made of pebbles or of sand. Anyhow, there are frequently Lithothamnion terraces slightly inclinated towards the bottom (chemical analysis table 1).

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ABSTRACT The species of the genus Byrsonima Rich. ex Kunth are of great medicinal and economic importance, but they are still poorly studied with respect to their propagules. This study describes, illustrates and comparse morphological aspects of the pyrenes of Byrsonima crassifolia (L.) Kunth, Byrsonima verbascifolia (L.) DC. and Byrsonima coccolobifolia Kunth occurring in areas of savannah of Boa Vista, Roraima. The pyrenes are globoid, obovoid to ovoid, with endocarp dark brown in color, with a corrugated and reticulate surface and corneous consistency. They possess distinctly septate locules with or without seeds, the outer wall of which are dark brown in color with corneous consistency and thin black inner walls also with corneous consistency. The number of locules and seeds per pyrene among the species varies. The seeds are exalbuminous, globoid, obovoid to ovoid, with a thin, smooth integument and are light-brown in color. They have radicular lobes and hypostasis. The embryo is continuous and axial with cylindrical spirally rolled cotyledons. The diameter of pyrenes of Byrsonima crassifolia is greater than in the other two species. The pyrenes of B. coccolobifolia are longer and heavier, while those of B. verbascifolia are lighter and the seeds have greater lengths, widths and thickness compared to the other two species studied. The three species have similar morphologies, differing in the size and weight of pyrenes and seeds.

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The focus of this research was to evaluate the horizontal pressures on a cylindrical metal silo of corrugated walls and flat bottom with 1.82m diameter and 5.4m high, and to compare the values with those obtained theoretically by the ISO 11697, EP 433 and AS 3774 standards. The silo was symmetrically filled and constant speed with wheat cv. soft red for two different height/diameter ratios (H/D) and was unloaded through three orifices with a diameter of 71.6mm, one concentric and two eccentrics. Horizontal pressures were measured on the walls of the silo at three positions using hydraulic type pressure cells. The results showed that shortly after the start of the unloading, there was a mass flow above the quota of H/D = 1.2, whereas below this quota funnel flow occurred. It can be said that the EP 433 standard was more appropriate to predict horizontal pressures in silos in H/D ratio = 1.0, with eccentric unloading. For the H/D ratio = 1.5, AS 3774 standard was the one that produced values closer to the experimental.

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Abstract: The aim of the present study was to report the occurrence of members of the Mollicutesclass in the reproductive system of dairy cattle in Brazil. Five farms containing dairy cattle were visited in January of 2012. In total, 100 cows of different ages, breeds and stages of lactation were examined in the present study. The cows were part of intensive or semi-intensive management systems and were submitted to mechanical milking or hand milking. The samples were collected after washing the vulvar region with water and soap, and then drying it with paper towels and disinfecting the area with alcohol (70°GL). Vaginal mucous was collected using a sterile alginate cotton swab, which was rubbed on the vagina, as well as the lateral and internal walls. Vulvovaginal mucous samples were cultured in both liquid and solid modified Hayflick´s medium, for mycoplasmas, and UB medium, for ureaplasmas. The PCR assays for Mollicutesand Ureaplasmaspp. were performed according to the standard protocols described in the current literature. During isolation, the frequency of Mycoplasmaspp. was of 13.0% (13/100) and for Ureaplasmaspp. was of 6.0% (6/100). In the PCR assays the frequency of Mollicuteswas of 26.0% (26/100) and for Ureaplasmaspp. was of 13.0% (13/100) in the dairy cattle studied. This is the first report of these agents in reproductive system of bovine of the Pernambuco state. Further studies are necessary to determine the pathogenic potential and species of these field isolates.

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The classical treatment of rough wall turbulent boundary layers consists in determining the effect the roughness has on the mean velocity profile. This effect is usually described in terms of the roughness function delta U+. The general implication is that different roughness geometries with the same delta U+ will have similar turbulence characteristics, at least at a sufficient distance from the roughness elements. Measurements over two different surface geometries (a mesh roughness and spanwise circular rods regularly spaced in the streamwise direction) with nominally the same delta U+ indicate significant differences in the Reynolds stresses, especially those involving the wall-normal velocity fluctuation, over the outer region. The differences are such that the Reynolds stress anisotropy is smaller over the mesh roughness than the rod roughness. The Reynolds stress anisotropy is largest for a smooth wall. The small-scale anisotropy and interniittency exhibit much smaller differences when the Taylor microscale Reynolds number and the Kolmogorov-normalized mean shear are nominally the same. There is nonetheless evidence that the small-scale structure over the three-dimensional mesh roughness conforms more closely with isotropy than that over the rod-roughened and smooth walls.

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The present study combines the examination of toxins produced by C. cassiicola and the effects of the fungus colonization on L. camara. C. cassiicola was cultivated on solid media and the crude extracts CAE and CE were produced. Both extracts were submitted to a seed germination and growth assay utilizing Physalis ixocarpa, Trifolium alexandrinum, Lolium multiflorum and Amaranthus hypochodriacus. The effect of the extracts on the ATP-synthesis in isolated spinach chloroplasts was also tested. Bioassay guided chromatographic fractionation identified the most active extract (CAE). From this extract ergosta-4,6,8(14),22-tetraen-3-one (C1) and fatty acids were isolated. The C1 compound reduce ATP synthesis in isolated spinach chloroplasts. The interference of fatty acids with ATP synthesis and also with weed growth provides one explanation of the phytogrowth-inhibitory properties of such fungal extracts. Histological observations involving fungus-plant interaction were made on L. camara plants inoculated with C. cassiicola conidia suspension. After inoculations, fragments of the leaf blades were prepared for observation by light and scanning electron microscopy. Fungal colonization of Lantana camara was typical of a necrotroph and penetration initiated a hypersensitive response. L. camara reacted to the pathogen penetration through thickening of the epidermis walls, cytoplasm granulation and a cicatrisation tissue.

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Mature leaves of Paepalanthus superbus exhibit intercellular protuberances between the inner periclinal walls of the epidermal and the parenchyma cells surface, as well as on the surface of the parenchyma mesophyll cells. These structures are mostly prominent around the parenchyma cells, forming a gel capsule-like structure. Histochemical tests with ruthenium red indicate the pectic nature of the intercellular deposits, with scattered lipidic inclusions as revealed by sudan IV and sudan black B. Ultrastructural analyses show a fibrillar matrix with scattered fimbriate and tubular structures, and a distinct margin delimited by a dense membrane-like structure. Our results suggest that the protuberances are derived from secretory activity, and are formed after the development of the intercellular spaces. For P. superbus this structure may represent an important cell wall specialisation, related with the adhesion and transport mechanisms between cells.

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Dialypetalanthus fuscescens is an Amazonian endemic species with problematic taxonomic position. This neotropical rainforest tree belongs to the monospecific Dialypetalanthaceae. In the present work, we analysed the leaf cell-wall polysaccharide composition of Dialypetalanthus fuscescens and compared it to that of Bathysa meridionalis (Rubiaceae-Cinchonoideae). Glycosyl composition and glycosyl-linkage analysis indicated that both species have similar cell wall composition. Arabinogalactans were the major component of the pectic polysaccharides and xylans, although being reported in minor amounts in dicots, were found to be the predominant hemicellulosic polysaccharide in cell walls of both species. These findings are in agreement with previous data on cell wall composition reported for Rubiaceae and corroborate the current suggestion of the possible link between this family and Dialypetalanthaceae.

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The chalazal megaspore develops in a Polygonum-type embryo sac. The amyloplast-rich endothelium is partially degraded during the expansion of the micropylar portion of the megagametophyte. Organization of the mature embryo sac is determined by the patterns of vacuolation, nuclear migration, spindle orientation and cellularization. The egg cell is slightly chalazal in relation to the synergids, and its micropylar end does not touch the micropylar channel. At the chalazal pole of the egg apparatus, the common walls between the synergids, the egg and central cells, despite their tenuity, are present in the mature megagametophyte. The polar nuclei do not fuse before fertilization and the antipodals are persistent until the first stages of endosperm formation. The taxonomic significance of some embryological characters for the Bignoniaceae is discussed.

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Galactomannans (GM) are storage cell wall polysaccharides present in endospermic seeds of legumes. They are thought to be storage polymers, since it has been observed for a few species (among them Sesbania virgata) that they are completely broken down after germination and their products are transferred to the growing embryo. We examined the effect of 10-4 M abscisic acid (ABA) on the degradation of galactomannan in isolated endosperms and intact seeds of S. virgata. We found that after seed germination the initial embryo growth was retarded. Ultrastructural analysis showed that the embryo is completely surrounded by an endosperm which displays very thick galactomannan-containing cell walls. Although an inhibitory effect has been observed on the increase of fresh mass of the embryo, the effect of ABA on the dry mass was weaker and transitory (from 48 to 96 h). Endosperm dry mass and galactomannan degradation were significantly inhibited and the activity of alpha-galactosidase was strongly affected. The addition of ABA before and/or after the start of mobilisation in intact seeds or isolated endosperms, showed that whereas addition before mobilisation did not affect dry mass decrease in intact seeds, it was strongly affected in isolated endosperms. On the other hand, whereas it affected embryo fresh mass increase in intact seeds, but not in isolated embryos, no significant effect was observed on dry mass. These results suggest that ABA affects galactomannan degradation and by doing so, prevents water absorption by the embryo, rather than affect its dry mass. As ABA has been detected in the endosperm of seeds of S. virgata, it is proposed that it probably acts as a modulator of galactomannan mobilisation and consequently synchronises it with early growth of the embryo.

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Leaves of Struthanthus vulgaris Mart. (Loranthaceae) exhibit galls induced by a Hymenoptera. These galls pass through five developmental stages. In the first stage, a small brown swelling is observed on the surface of the leaf. Internally, the chlorenchyma cells around the eggs of the gall-makers are divided. In the second stage, the gall enlarges and its surface assumes a wavy appearance with a depressed region in its center. Within this depression, an incompletely divided gall chamber with embryos is observed. Neoformed parenchyma is present around the chamber and the secondary walls of fibers and sclereids are no longer observed. The vascular parenchyma shows hyperplasia. In the third stage, the gall grows larger and adopts an ellipsoidal shape. Fissures appear on the gall epidermis and the neoformed parenchyma is conspicuous, with a cortical and a medullar region. In the medullar region, each gall chamber, with one inducer in larval phase, is lined with 1-2 layers of nutritive tissue. The gall is larger still at the fourth stage of development and a periderm coats most of the gall. New vascular bundles, sclereids, and fibers are formed. The gall-makers are in advanced larval phase and no nutritive tissue cells are observed. In the fifth stage, the gall reaches its definitive size and the inducers are in the pupa phase. At this stage, the cortical region undergoes slight hypertrophy. The senescent gall shows the orifices of the exit channel made by the adult gallmakers. The anatomical studies of the hymenopteran gall enabled to compare this gall with a dipteran one, previously discribed in the same plant host. It is suggested that during the maturation of the gall, specific key processes are triggered, which bring about a specific cecidogenesis.

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The meristematic endodermis in adventitious roots of Richterago species originates in one of the fundamental meristem cells, which undergo sucessive anticlinal and periclinal divisions to build the inner cortex. The meristematic endodermis or proendodermis remains as a meristematic layer until its differentiation into endodermis, with Casparian strip. When sieve elements differentiate, endodermic secretory canals of esquizogenous origin are present at the region adjacent to primary phloem. Articulated laticifers, with cells perforated at both terminal and transversal walls, also occur during initial phases of secondary development. Presence of inulin as reserve carbohydrate in the inner cortex and vascular tissue may be related to abiotic factors, as an adaptive strategy of these species.