946 resultados para Apex Chert


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Pós-graduação em Agronegócio e Desenvolvimento - Tupã

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In social species, breeding system and gregarious behavior are key factors influencing the evolution of large-scale population genetic structure. The killer whale is a highly social apex predator showing genetic differentiation in sympatry between populations of foraging specialists (ecotypes), and low levels of genetic diversity overall. Our comparative assessments of kinship, parentage and dispersal reveal high levels of kinship within local populations and ongoing male-mediated gene flow among them, including among ecotypes that are maximally divergent within the mtDNA phylogeny. Dispersal from natal populations was rare, implying that gene flow occurs without dispersal, as a result of reproduction during temporary interactions. Discordance between nuclear and mitochondrial phylogenies was consistent with earlier studies suggesting a stochastic basis for the magnitude of mtDNA differentiation between matrilines. Taken together our results show how the killer whale breeding system, coupled with social, dispersal and foraging behaviour, contributes to the evolution of population genetic structure.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The region of San Pedro de Atacama, Northern Chile, has undergone several cultural and social changes after humans settled in Atacama Desert around 500 BC. The Atacameno people experienced the highest degree of social and cultural changes between 400 and 900 AD when they were assimilated into the Tiwanaku trade and political web that influenced most of the Central-Southern Andes. Under the influence of Tiwanaku, San Pedro de Atacama experienced its greatest economic development. Prior analyses of local human skeletal remains have shown a significant increase in the stature of the local population during the same period. In this paper, we investigate the impact of the Tiwanaku influence on the local epidemiological profile using the incidence of periostitis and osteomyelitis as indicators of biological stress. Surprisingly, the best epidemiological condition occurred during the final phase of influence of Tiwanaku (910-960 AD), and not during the apex influence (480-920 AD), as expected by the archaeological context. We suggest that population growth and aggregation may have counteracted the benefits of improved nutrition during the peak Tiwanaku influence. A severe drought occurred between 1,100 and 1,400 AD in Northern Chile. This could also explain the marked increase of bone infections in the post-Tiwanaku period (920-1,240 AD).

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OBJECTIVE: To evaluate the ability of orbital apex crowding volume measurements calculated with multidetector-computed tomography to detect dysthyroid optic neuropathy. METHODS: Ninety-three patients with Graves' orbitopathy were studied prospectively. All of the patients underwent a complete neuro-ophthalmic examination and computed tomography scanning. Volumetric measurements were calculated from axial and coronal contiguous sections using a dedicated workstation. Orbital fat and muscle volume were estimated on the basis of their attenuation values (in Hounsfield units) using measurements from the anterior orbital rim to the optic foramen. Two indexes of orbital muscle crowding were calculated: i) the volumetric crowding index, which is the ratio between soft tissue (mainly extraocular muscles) and orbital fat volume and is based on axial scans of the entire orbit; and ii) the volumetric orbital apex crowding index, which is the ratio between the extraocular muscles and orbital fat volume and is based on coronal scans of the orbital apex. Two groups of orbits (with and without dysthyroid optic neuropathy) were compared. RESULTS: One hundred and two orbits of 61 patients with Graves' orbitopathy met the inclusion criteria and were analyzed. Forty-one orbits were diagnosed with Graves' orbitopathy, and 61 orbits did not have optic neuropathy. The two groups of orbits differed significantly with regard to both of the volumetric indexes (p<0.001). Although both indexes had good discrimination ability, the volumetric orbital apex crowding index yielded the best results with 92% sensitivity, 86% specificity, 81%/94% positive/negative predictive value and 88% accuracy at a cutoff of 4.14. CONCLUSION: This study found that the orbital volumetric crowding index was a more effective predictor of dysthyroid optic neuropathy than previously described computed tomography indexes were.

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A new species of Stephanopodium (Dichapetalaceae) from tabuleiro forests in southern Bahia is here described and illustrated. This species, named Stephanopodium gracile because of its slender habit, is compared to S. blanchetianum and S. organense. From these two species, S. gracile can be distinguished by the inflorescences on the apical portion of the leaf petiole, young branches with sparse short appressed trichomes, and glabrous leaves; from S. blanchetianum it differs also by leaf blades with an acuminate (vs. usually obtuse or rounded, and sometimes acute) apex.

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Colostrum intake in newborn goat kids is essential for the acquisition of immunoglobulins (Ig) and influencing development of gastrointestinal mucosa. The present study investigated small intestine structure in the postnatal goat kid fed lyophilized bovine colostrum, an alternative source of antibodies to small ruminants, or goat colostrum using scanning electron microscopy technique. At 0,7 and 14 h of life 15 male newborns received 5% of body weight of lyophilized bovine colostrum (LBC) and 14 goat colostrum (GC), both with 55 mg/mL of IgG. Samples of duodenum, medium jejunum and ileum were collected at 18, 36 and 96 h of life. Three animals were sampled at birth without colostrum intake (0 h). The enteric tissues were analyzed for villi density (villi/cm(2)) and morphological characteristics. The villi density did not differ between treatment, sampling time and intestinal segments (P>0.05). The morphological characteristics were not different between LBC and GC in all segments. Duodenal villi were fingerlike, thick and short, and with different heights. Duodenal folds could also be verified. Frequent anastomoses in all sampling times were observed in this segment. In the jejunum, fingerlike villi, thin and thick, of different heights were observed in all sampling times as well as leaf-shaped villi. Vacuoles with colostrum were observed in the jejunum of goats sampled at 18 h of life. In ileum, fingerlike villi were observed in all sampling times. At 0 and 96 h of life, thick and low villi were verified while at 18 and 36 h the villi showed different heights and widths. At all sampling times, regularly cell extrusion processes were observed with grouped cells at the apex of the ileum villi and with isolated cells along the villi. In the first 4 days of goat kids' life the small intestine structure was unaffected by different sources of colostrum, goat or lyophilized bovine, and by the replacement of fetal enterocytes, which are able to absorb macromolecules, by adult-type ones. (C) 2011 Elsevier B.V. All rights reserved.

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Early diagenetic chert, infrequently exploited in Phanerozoic micropaleontology, was examined for organic-walled microfossils in petrographic thin sections of silicified dolostones from diverse levels and localities of the Assistencia Formation (Permian, Parana Basin) in the state of Sao Paulo, Brazil. In contrast to previous palynological studies of this formation, the use of thin sections allowed direct observation in three dimensions of common palynomorphs, as well as benthic microbial mats preserved in situ in various stages of their life cycles and degradation. As in palynological residues from the more wellknown shale of this formation, the chert contains wind-dispersed pollen grains and phytoclasts derived from terrestrial sources and planktonic cryptarchs (unornamented coccoidal unicellular or colonial palynomorphs). However, only in the chert is it possible to see much more delicate microfossils, such as abundant cyanobacteria of the in situ benthic microbiota as well as chlorophycean microalgae of the microphytoplankton. Post-depositional processes affecting the formation have destroyed all but the most resistant organic remains in the other lithologies, such that only rare, degraded pollen grains are seen in the unsilicified dolostone of the formation, and in the shale the vast majority of microfossils have been compacted to flattened disks. On the other hand, early silicification not only preserved organic remains at an incipient stage of decomposition but also impeded significant further degradation due to compaction, recrystallization, and oxidation. Thus, the petrographic study of such chert can complement traditional palynological investigations in Phanerozoic rocks by furnishing hitherto unavailable information, especially with regard to benthic organic microfossils and fragile organic-walled phytoplankton normally absent from organic residues. (C) 2011 Elsevier Ltd. All rights reserved.

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We performed morphological and molecular studies of Laurencia catarinensis from the Canary Islands. This species has an entangled habit, cushion-like tuft formation, cortical cell walls, slightly to markedly projecting near the apex, and lacking lenticular thickenings in medullary cells. We inferred its phylogenetic position by analyzing the chloroplast-encoded rbcL gene sequences from 41 samples. The results demonstrate that specimens of L. catarinensis from the Canary Islands, where it is referred to as L. intricata, and those from Brazil (including specimens from the type locality in Santa Catarina) form a monophyletic clade with low genetic divergence (0-0.9%). In contrast, specimens of L. intricata from the type locality in Cuba, Mexico, and the USA were clearly distinct from L. catarinensis collected in Brazil and the Canary Islands, as shown by high genetic divergence values (4.9-5.7%). The type material of L. catarinensis from Brazil allowed us to identify all samples from the Canarian Archipelago as L. catarinensis. These findings expand the known geographical distribution of L. catarinensis to the eastern Atlantic Ocean and demonstrate an amphi-Atlantic distribution of the species.

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The male of Potiicoara brasiliensis is reported for the first time with evidence of sexual dimorphism. Male diagnostic characters are described and compared with the other three species of Spelaeogriphidae. Males present differential morphology on both distal podomere articles of the antennula and antenna, an elongate and curved bare endopod on pleopod 2, a pair of short round penes on the sternum near the base of pereopod 7, and telson with dorsum almost smooth and apex straight. Material is sampled for the first time from karstic areas north of the species type-locality, Gruta Ricardo Franco near Corumba City, and Gruta do Curupira in the Araras Mountains. These new findings expand the distribution of the species over seven hundred kilometers. Comparisons between exemplars of both sexes are presented. A hypothesis on the distributional pattern of P. brasiliensis is introduced based on the geological history of Central-West Brazil.

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As one of the few areas apt for horticulture in Northern Chile's arid landscape, the prehistory of the Atacama oases is deeply enmeshed with that of the inter-regional networks that promoted societal development in the south central Andes. During the Middle Horizon (AD 5001000), local populations experienced a cultural apex associated with a substantial increase in inter-regional interaction, population density, and quantity and quality of mortuary assemblages. Here, we test if this cultural peak affected dietary practices equally among the distinct local groups of this period. We examine caries prevalence and the degree of occlusal wear in four series recovered from three cemeteries. Our results show a reduction in the prevalence of caries for males among an elite subsample from Solcor 3 and the later Coyo 3 cemeteries. Dental wear tends to increase over time with the Late Middle Horizon/Late Intermediate Period cemetery of Quitor 6 showing a higher average degree of wear. When considered in concert with archaeological information, we concluded that the Middle Horizon was marked by dietary variability wherein some populations were able to obtain better access to protein sources (e.g., camelid meat). Not all members of Atacameno society benefited from this, as we note that this dietary change only affected men. Our results suggest that the benefits brought to the San Pedro oases during the Middle Horizon were not equally distributed among local groups and that social status, relationship to the Tiwanaku polity, and interment in particular cemeteries affected dietary composition. Am J Phys Anthropol, 2012. (C) 2012 Wiley Periodicals, Inc.

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In this work, it was observed a straight relationship between the manipulation of the reduced glutathione (GSH)/glutathione disulfide (GSSG) ratio, nitric oxide emission and quality and number of early somatic embryos in Araucaria angustifolia, a Brazilian endangered native conifer. In low concentrations GSH (0.01 and 0.1 mM) is a potential NO scavenger in the culture medium. Furthermore, it can increase the number of early SE formed in cell suspension culture media in a few days. However, the maintenance in this low redox state lead to a loss of early somatic embryos polarization. In gelled culture medium, high levels of GSH (5 mM) allows the development of globular embryos presenting a high NO emission on embryo apex, stressing its importance in the differentiation and cell division. Taken together these results indicate that the modification of the embryogenic cultures redox state might be an effective strategy to develop more efficient embryogenic systems in A. angustifolia. (c) 2012 Elsevier Ireland Ltd. All rights reserved.

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Objectives: To evaluate the effect of insertion torque on micromotion to a lateral force in three different implant designs. Material and methods: Thirty-six implants with identical thread design, but different cutting groove design were divided in three groups: (1) non-fluted (no cutting groove, solid screw-form); (2) fluted (901 cut at the apex, tap design); and (3) Blossomt (Patent pending) (non-fluted with engineered trimmed thread design). The implants were screwed into polyurethane foam blocks and the insertion torque was recorded after each turn of 901 by a digital torque gauge. Controlled lateral loads of 10N followed by increments of 5 up to 100N were sequentially applied by a digital force gauge on a titanium abutment. Statistical comparison was performed with two-way mixed model ANOVA that evaluated implant design group, linear effects of turns and displacement loads, and their interaction. Results: While insertion torque increased as a function of number of turns for each design, the slope and final values increased (Po0.001) progressively from the Blossomt to the fluted to the non-fluted design (M +/- standard deviation [SD] = 64.1 +/- 26.8, 139.4 +/- 17.2, and 205.23 +/- 24.3 Ncm, respectively). While a linear relationship between horizontal displacement and lateral force was observed for each design, the slope and maximal displacement increased (Po0.001) progressively from the Blossomt to the fluted to the non-fluted design (M +/- SD 530 +/- 57.7, 585.9 +/- 82.4, and 782.33 +/- 269.4 mm, respectively). There was negligible to moderate levels of association between insertion torque and lateral displacement in the Blossomt, fluted and non-fluted design groups, respectively. Conclusion: Insertion torque was reduced in implant macrodesigns that incorporated cutting edges, and lesser insertion torque was generally associated with decreased micromovement. However, insertion torque and micromotion were unrelated within implant designs, particularly for those designs showing the least insertion torque.

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O tipo de alimentação depende do ambiente em que o animal se encontra, sendo este um fator responsável pela alteração da morfologia, como a estratificação e o nível de queratinização da língua, e a funcionalidade da mesma. Dentre as estruturas morfológicas funcionais da língua, as papilas vêm merecendo destaque devido a sua estreita relação com a dieta. Foram utilizadas duas espécies de cervídeos: cinco Mazama gouazoubira e duas Mazama americana, dividindo-se a língua em três partes: ápice, corpo e raiz. Analisou comparativamente a língua de duas espécies por meio de microscopia de luz e eletrônica de varredura. As papilas filiforme, fungiforme e valada apresentaram na língua das duas espécies estudadas, e com a mesma distribuição, mudando apenas a quantidade e formato de papilas filiformes no ápice lingual e a quantidade e disposição das papilas valadas na raiz da língua, fator este que pode ser ligado à dieta dos animais. . Além disto, sua distribuição é semelhante à de outras espécies de herbívoros.