851 resultados para rock forming
Resumo:
The rock-wallaby genus Petrogale comprises a group of habitat-specialist macropodids endemic to Australia. Their restriction to rocky outcrops, with infrequent interpopulation dispersal, has been suggested as the cause of their recent and rapid diversification. Molecular phylogenetic relationships within and among species of Petrogale were analysed using mitochondrial (cytochrome oxidase c subunit 1, cytochrome b. NADH dehydrogenase subunit 2) and nuclear (omega-globin intron, breast and ovarian cancer susceptibility gene) sequence data with representatives that encompassed the morphological and chromosomal variation within the genus, including for the first time both Petrogale concinna and Petrogale purpureicollis. Four distinct lineages were identified, (1) the brachyotis group, (2) Petrogale persephone, (3) Petrogale xanthopus and (4) the lateralis-penicillata group. Three of these lineages include taxa with the ancestral karyotype (2n = 22). Paraphyletic relationships within the brachyotis group indicate the need for a focused phylogeographic study. There was support for P. purpureicollis being reinstated as a full species and P. concinna being placed within Petrogale rather than in the monotypic genus Peradorcas. Bayesian analyses of divergence times suggest that episodes of diversification commenced in the late Miocene-Pliocene and continued throughout the Pleistocene. Ancestral state reconstructions suggest that Petrogale originated in a mesic environment and dispersed into more arid environments, events that correlate with the timing of radiations in other arid zone vertebrate taxa across Australia. Crown Copyright (C) 2011 Published by Elsevier Inc. All rights reserved.
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Bertuzzi, R, Franchini, E, Tricoli, V, Lima-Silva, AE, Pires, FDO, Okuno, NM, and Kiss, MAPDM. Fit-climbing test: A field test for indoor rock climbing. J Strength Cond Res 26(6): 1558-1563, 2012-The aim of this study was to develop an indoor rock-climbing test on an artificial wall (Fit-climbing test). Thirteen climbers (elite group [EG] = 6; recreational group [RG] = 7) performed the following tests: (a) familiarization in the Fitclimbing test, (b) the Fit-climbing test, and (c) a retest to evaluate the Fit-climbing test's reliability. Gas exchange, blood lactate concentration, handgrip strength, and heart rate were measured during the test. Oxygen uptake during the Fit-climbing test was not different between groups (EG = 8.4 +/- 1.1 L; RG = 7.9 +/- 1.5 L, p > 0.05). The EG performance (120 +/- 7 movements) was statistically higher than the RG climbers' performance (78 +/- 13 movements) during the Fit-climbing test. Consequently, the oxygen cost per movement during the Fit-climbing test of the EG was significantly lower than that of the RG (p < 0.05). Handgrip strength was higher in the EG when compared with that in the RG in both pre-Fit- and post-Fit-climbing test (p < 0.05). There were no significant differences in any other variables analyzed during the Fit-climbing test (p > 0.05). Furthermore, the performance in the Fit-climbing test presented high reliability (intraclass correlation coefficient = 0.97). Therefore, the performance during the Fit-climbing test may be an alternative to evaluate rock climbers because of its specificity and relation to oxygen cost per movement during climbing.
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The Neoproterozoic post-collisional period in southern Brazil (650-580 Ma) is characterized by substantial volumes of magma emplaced along the active shear zones that compose the Southern Brazilian Shear Belt. The early-phase syntectonic magmatism (630-610 Ma) is represented by the porphyritic, high-K, metaluminous to peraluminous Quatro Ilhas Granitoids and the younger heterogranular, slightly peraluminous Mariscal Granite. Quatro II has Granitoids include three main petrographic varieties (muscovite-biotite granodiorite mbg; biotite monzogranite - bmz: and leucogranite - lcg) that, although sharing some significant geochemical characteristics, are not strictly comagmatic, as shown by chemical and Sr-Nd-Pb isotope data. The most primitive muscovite-biotite granodiorite was produced by contamination of more mafic melts (possibly with some mantle component) with peraluminous crustal melts; the biotite monzogranite, although more felsic, has higher Ca, MgO,TiO2 and Ba, and lower K2O, FeOt, Sr and Rb contents, possibly reflecting some mixing with coeval mafic magmas of tholeiitic affinity; the leucogranite may be derived from pure crustal melts. The Mariscal Granite is formed by two main granite types which occur intimately associated in the same pluton, one with higher K (5-6.5 wt.% K2O) high Rb and lower CaO, Na2O, Ba and Zr as compared to the other (3-5 wt.% of K2O). The two Mariscal Granite varieties have compositional correspondence with fine-grained granites (fgg) that occur as tabular bodies which intruded the Quatro Ilhas Granoitoids before they were fully crystallized, and are inferred to correspond to the Mariscal Granite feeders, an interpretation that is reinforced by similar U-Pb zircon crystallization ages. The initial evolution of the post-collisional magmatism, marked by the emplacement of the Quatro Ilhas Granitoids varieties, activated sources that produced mantle and crustal magmas whose emplacement was controlled both by flat-lying and transcurrent structures. The transition from thrust to transcurrent-related tectonics coincides with the increase in the proportion of crustal-derived melts. The transcurrent tectonics seems to have played an essential role in the generation of mantle-derived magmas and may have facilitated their interaction with crustal melts which seem to be to a large extent the products of reworking of orthogneiss protoliths. (C) 2012 Elsevier B.V. All rights reserved.
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The interference of some specific aqueous two-phase system (ATPS) phase-forming components in bovine serum albumin (BSA) determination by the Bradford method was investigated. For this purpose, calibration curves were obtained for BSA in the presence of different concentrations of salts and polymers. A total of 19 salts [Na2SO4, (NH4)(2)SO4, MgSO4, LiSO4, Na2HPO4, sodium phosphate buffer (pH 7.0), NaH2PO4, K2HPO4, potassium phosphate buffer (pH 7.0), KH2PO4, C6H8O7, Na3C6HSO7, KCHO2, NaCHO2, NaCO3, NaHCO3, C2H4O2, sodium acetate buffer (pH 4.5), and NaC2H3O2] and 7 polymers [PEG 4000, PEG 8000, PEG 20000, UCON 3900, Ficoll 70000, PES 100000, and PVP 40000] were tested, and each calibration curve was compared with the one obtained for BSA in water. Some concentrations of salts and polymers had considerable effect in the BSA calibration curve. Carbonate salts were responsible for the highest salt interference, whereas citric and acetic acids did not produce interference even in the maximum concentration level tested (5 wt%). Among the polymers, UCON gave the highest interference, whereas Ficoll did not produce interference when used in concentrations up to 10 wt%. It was concluded that a convenient dilution of the samples prior to the protein quantification is needed to ensure no significant interference from ATPS phase-forming constituents. (C) 2011 Elsevier Inc. All rights reserved.
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Background: Most investigations regarding the First Americans have primarily focused on four themes: when the New World was settled by humans; where they came from; how many migrations or colonization pulses from elsewhere were involved in the process; and what kinds of subsistence patterns and material culture they developed during the first millennia of colonization. Little is known, however, about the symbolic world of the first humans who settled the New World, because artistic manifestations either as rock-art, ornaments, and portable art objects dated to the Pleistocene/Holocene transition are exceedingly rare in the Americas. Methodology/Principal Findings: Here we report a pecked anthropomorphic figure engraved in the bedrock of Lapa do Santo, an archaeological site located in Central Brazil. The horizontal projection of the radiocarbon ages obtained at the north profile suggests a minimum age of 9,370640 BP, (cal BP 10,700 to 10,500) for the petroglyph that is further supported by optically stimulated luminescence (OSL) dates from sediment in the same stratigraphic unit, located between two ages from 11.7 +/- 0.8 ka BP to 9.9 +/- 0.7 ka BP. Conclusions: These data allow us to suggest that the anthropomorphic figure is the oldest reliably dated figurative petroglyph ever found in the New World, indicating that cultural variability during the Pleistocene/Holocene boundary in South America was not restricted to stone tools and subsistence, but also encompassed the symbolic dimension.
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Many techniques have been proposed for root coverage. However, none of them presents predictable results in deep and wide recessions. Objective: The aim of this case series report is to describe an alternative technique for root coverage at sites showing deep recessions and attachment loss >4 mm at buccal sites. Material and Methods: Four patients presenting deep recession defects at buccal sites (>= 4 mm) were treated by the newly forming bone graft technique, which consists in the creation of an alveolar socket at edentulous ridge and transferring of granulation tissue present in this socket to the recession defect after 21 days. Clinical periodontal parameters, including recession depth (RD), probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), plaque index (PI) and keratinized gingiva width (KGW) were evaluated by a single examiner immediately before surgery and at 1, 3, 6 and 9 months postoperatively. Results: All cases showed reduction in RD and PD, along with CAL gain, although no increase in KGW could be observed. These findings suggest that the technique could favor periodontal regeneration along with root coverage, especially in areas showing deep recessions and attachment loss.
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In the present study, we evaluated peripheral and central auditory pathways in professional musicians (with and without hearing loss) compared to non-musicians. The goal was to verify if music exposure could affect auditory pathways as a whole. This is a prospective study that compared the results obtained between three groups (musicians with and without hearing loss and non-musicians). Thirty-two male individuals participated and they were assessed by: Immittance measurements, pure-tone air conduction thresholds at all frequencies from 0.25 to 20 kHz, Transient Evoked Otoacoustic Emissions, Auditory Brainstem Response (ABR), and Cognitive Potential. The musicians showed worse hearing thresholds in both conventional and high frequency audiometry when compared to the non-musicians; the mean amplitude of Transient Evoked Otoacoustic Emissions was smaller in the musicians group, but the mean latencies of Auditory Brainstem Response and Cognitive Potential were diminished in the musicians when compared to the non-musicians. Our findings suggest that the population of musicians is at risk for developing music-induced hearing loss. However, the electrophysiological evaluation showed that latency waves of ABR and P300 were diminished in musicians, which may suggest that the auditory training to which these musicians are exposed acts as a facilitator of the acoustic signal transmission to the cortex.
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The Cretaceous Banhado alkaline complex in southeastern Brazil presents two potassic SiO2-undersaturated series. The high-Ca magmatic series consist of initially fractionated olivine (Fo(92-91)) + diopside (Wo(48-43)En(49-35)Ae(0-7)), as evidenced by the presence of xenocrysts and xenoliths. In that sequence, diopside (Wo(47-38)En(46-37)Ae(0-8)) + phlogopite + apatite + perovskite (Prv(> 92)) crystallized to form the phlogopite melteigite and led to the Ca enrichment of the magma. Diopside (Wo(47-41)En(32-24) Ae(3-14)) continued to crystallize as an early mafic mineral, followed by nepheline (Ne(74.8-70.1)Ks(26.3-21.2)Qz(7.6-0.9)) and leucite (Lc(65-56)) and subsequently by melanite and potassic feldspar (Or(85-99)Ab(1-7)) to form melanite ijolites, wollastonite-melanite urtites and melanite-nepheline syenites. Melanite-pseudoleucite-nepheline syenites are interpreted to be a leucite accumulation. Melanite nephelinite dykes are believed to represent some of the magmatic differentiation steps. The low-Ca magmatic series is representative of a typical fractionation of aegirine-augite (Wo(36-29)En(25-4)Ae(39-18)) + alkali feldspar (Or(57-96)Ab(3-43)) + nepheline (Ne(76.5-69.0)Ks(19.9-14.4)Qz(15.1-7.7)) + titanite from phonolite magma. The evolution of this series from potassic nepheline syenites to sodic sodalite syenites and sodalitolites is attributed to an extensive fractionation of potassic feldspar, which led to an increase of the NaCl activity in the melt during the final stages forming sodalite-rich rocks. Phonolite dykes followed a similar evolutionary process and also registered some crustal assimilation. The mesocratic nepheline syenites showed interactions with phlogopite melteigites, such as compatible trace element enrichments and the presence of diopside xenocrysts, which were interpreted to be due to a mixing/mingling process of phonolite and nephelinite magmas. The geochemical data show higher TiO2 and P2O5 contents and lower SiO2 contents for the high-Ca series and different LILE evolution trends and REE chondrite-normalized patterns as compared to the low-Ca series. The Sr-87/Sr-86, Nd-143/Nd-144, Pb-206/Pb-204 and Pb-208/Pb-204 initial ratios for the high-Ca series (0.70407-0.70526, 0.51242-0.51251, 17.782-19.266 and 38.051-39.521, respectively) were slightly different from those of the low-Ca series (0.70542-0.70583, 0.51232-0.51240, 17.758-17.772 and 38.021-38.061, respectively). For both series, a CO2-rich potassic metasomatized lithospheric mantle enriched the source with rutile-bearing phlogopite clinopyroxenite veins. Kamafugite-like parental magma is attributed to the high-Ca series with major contributions from the melting of the veins. Potassic nephelinite-like parental magma is assigned to the low-Ca series, where the metasomatized wall-rock played a more significant role in the melting process.
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Eighteen aerobic endospore forming strains were isolated from sugarcane rhizosphere in N-free medium. A phenotypic description and analysis of the 5' end hypervariable region sequences of 16S rRNA revealed a high diversity of Bacillus and related genera. Isolates were identified, and four genera were obtained: seven strains belonged to Bacillus (Bacillaceae family), four belonged to Paenibacillus, six belonged to Brevibacillus and one strain was identified as Cohnella (Paenibacillaceae family). Four Brevibacillus strains showed in vitro inhibitory activity against plant pathogens fungi Curvularia and Fusarium. Seventy-four percent of the isolated bacteria grew on pectin as the only carbon source, showing polygalacturonase activity. Pectate lyase activity was detected for the first time in a Brevibacillus genus strain. All isolates showed endoglucanase activity. Calcium phosphate solubilisation was positive in 83.3% of the isolates, with higher values than those reported for Bacillus inorganic phosphate solubilising strains. High ethylene plant hormone secretion in the culture medium was detected in 22% of the bacteria. This is the first report of ethylene secretion in Paenibacillaceae isolates. Indole-3-acetic acid production was found in a Brevibacillus genus isolate. It was reported for the first time the presence of Cohnella genus strain on sugarcane rhizosphere bearing plant growth promoting traits. The sugarcane isolate Brevibacillus B65 was identified as a plant growth inoculant because it showed wider spectra of plant stimulation capabilities, including an antifungal effect, extracellular hydrolases secretion, inorganic phosphate solubilisation and plant hormone liberation. In this work, sugarcane was shown to be a suitable niche for finding aerobic endospore forming 'Bacilli' with agriculture biotechnological purposes.
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A combination of an extension of the topological instability "λ criterion" and the "average electronegativity" has been recently reported in the literature to predict compositions with high glass-forming ability (GFA). In the present work, both criteria have been applied to select the Ni61.0Nb36.0B3 alloy with a high glass-forming ability. Ingots were prepared by arc-melting and were used to produce ribbons processed by the melt-spinning technique further characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The Ni61.0Nb36.0B3 alloy revealed a complete amorphization and supercooled liquid region ΔTx = 68 K. In addition, wedge-shaped samples were prepared using copper mold casting in order to determine the critical thickness for amorphous formation. Scanning electron microscopy (SEM) revealed that fully amorphous samples could be obtained, reaching up to ~800 µm in thickness.
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To reliably determine the main physical parameters (masses and ages) of young stars, we must know their distances. While the average distance to nearby star-forming regions (<300 pc) is often known, the distances to individual stars are usually unknown. Individual distances to members of young moving groups can be derived from their radial velocities and proper motions using the convergent-point strategy. We investigate the kinematic properties of the Lupus moving group with the primary objective of deriving individual distances to all group members.
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The maintenance of biodiversity is a long standing puzzle in ecology. It is a classical result that if the interactions of the species in an ecosystem are chosen in a random way, then complex ecosystems can't sustain themselves, meaning that the structure of the interactions between the species must be a central component on the preservation of biodiversity and on the stability of ecosystems. The rock-paper-scissors model is one of the paradigmatic models that study how biodiversity is maintained. In this model 3 species dominate each other in a cyclic way (mimicking a trophic cycle), that is, rock dominates scissors, that dominates paper, that dominates rock. In the original version of this model, this dominance obeys a 'Z IND 3' symmetry, in the sense that the strength of dominance is always the same. In this work, we break this symmetry, studying the effects of the addition of an asymmetry parameter. In the usual model, in a two dimensional lattice, the species distribute themselves according to spiral patterns, that can be explained by the complex Landau-Guinzburg equation. With the addition of asymmetry, new spatial patterns appear during the transient and the system either ends in a state with spirals, similar to the ones of the original model, or in a state where unstable spatial patterns dominate or in a state where only one species survives (and biodiversity is lost).
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There is special interest in the incorporation of metallic nanoparticles in a surrounding dielectric matrix for obtaining composites with desirable characteristics such as for surface plasmon resonance, which can be used in photonics and sensing, and controlled surface electrical conductivity. We investigated nanocomposites produced through metallic ion implantation in insulating substrate, where the implanted metal self-assembles into nanoparticles. During the implantation, the excess of metal atom concentration above the solubility limit leads to nucleation and growth of metal nanoparticles, driven by the temperature and temperature gradients within the implanted sample including the beam-induced thermal characteristics. The nanoparticles nucleate near the maximum of the implantation depth profile (projected range), that can be estimated by computer simulation using the TRIDYN. This is a Monte Carlo simulation program based on the TRIM (Transport and Range of Ions in Matter) code that takes into account compositional changes in the substrate due to two factors: previously implanted dopant atoms, and sputtering of the substrate surface. Our study suggests that the nanoparticles form a bidimentional array buried few nanometers below the substrate surface. More specifically we have studied Au/PMMA (polymethylmethacrylate), Pt/PMMA, Ti/alumina and Au/alumina systems. Transmission electron microscopy of the implanted samples showed the metallic nanoparticles formed in the insulating matrix. The nanocomposites were characterized by measuring the resistivity of the composite layer as function of the dose implanted. These experimental results were compared with a model based on percolation theory, in which electron transport through the composite is explained by conduction through a random resistor network formed by the metallic nanoparticles. Excellent agreement was found between the experimental results and the predictions of the theory. It was possible to conclude, in all cases, that the conductivity process is due only to percolation (when the conducting elements are in geometric contact) and that the contribution from tunneling conduction is negligible.
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[EN] Granite is emplaced deep in the Earth's crust. It cools and crystallises and is subjected to thermal and magmatic events, and to recurrent stresses. It develops textures or fabrics as well as strain patterns which, as erosion brings the rock mass near the surface, find expression in various fracture sets and systems.
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Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto. Departamento de Biologia, Faculdade de Ciências da Universidade do Porto. EscolaUniversitaria de Enxeñeria Forestal, Universidade de Vigo