910 resultados para Morphological complexity


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This study investigates effects of syntactic complexity operationalised in terms of movement, intervention and (NP) feature similarity in the development of A’ dependencies in 4-, 6-, and 8-year old typically developing (TD) French children and children with Autism Spectrum Disorders (ASD). Children completed an off-line comprehension task testing eight syntactic structures classified in four levels of complexity: Level 0: No Movement; Level 1: Movement without (configurational) Intervention; Level 2: Movement with Intervention from an element which is maximally different or featurally ‘disjoint’ (mismatched in both lexical NP restriction and number); Level 3: Movement with Intervention from an element similar in one feature or featurally ‘intersecting’ (matched in lexical NP restriction, mismatched in number). The results show that syntactic complexity affects TD children across the three age groups, but also indicate developmental differences between these groups. Movement affected all three groups in a similar way, but intervention effects in intersection cases were stronger in younger than older children, with NP feature similarity affecting only 4-year olds. Complexity effects created by the similarity in lexical restriction of an intervener thus appear to be overcome early in development, arguably thanks to other differences of this intervener (which was mismatched in number). Children with ASD performed less well than the TD children although they were matched on non-verbal reasoning. Overall, syntactic complexity affected their performance in a similar way as in their TD controls, but their performance correlated with non-verbal abilities rather than age, suggesting that their grammatical development does not follow the smooth relation to age that is found in TD children.

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Given the long-term negative outcomes associated with depression in adolescence, there is a pressing need to develop brief, evidence based treatments that are accessible to more young people experiencing low mood. Behavioural Activation (BA) is an effective treatment for adult depression, however little research has focused on the use of BA with depressed adolescents, particularly with briefer forms of BA. In this article we outline an adaptation of brief Behavioral Activation Treatment of Depression (BATD) designed for adolescents and delivered in eight sessions (Brief BA). This case example illustrates how a structured, brief intervention was useful for a depressed young person with a number of complicating and risk factors.

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Previous research with children learning a second language (L2) has reported errors with verb inflection and cross-linguistic variation in accuracy and error patterns. However, owing to the cross-linguistic complexity and diversity of different verbal paradigms, the cross-linguistic effects on the nature of default forms has not been directly addressed in L2 acquisition studies. In the present study, we compared accuracy and error patterns in verbal agreement inflections in L2 children acquiring Dutch and Greek, keeping the children’s L1 constant (Turkish). Results showed that inflectional defaults in Greek follow universal predictions regarding the morphological underspecification of paradigms. However, the same universal predictions do not apply to the same extent to Dutch. It is argued that phonological properties of inflected forms should be taken into account to explain cross-linguistic differences in the acquisition of inflection. By systematically comparing patterns in child L2 Dutch and Greek, this study shows how universal mechanisms and target language properties work in tandem in the acquisition of inflectional paradigms.

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This study evaluated, by SEM, the morphology of human primary teeth roots. Twenty-four teeth were divided into 3 groups: pulp vitality (group I) and pulp necrosis without (group II) and with apical periodontitis (group III). Roots were analyzed by the presence of periodontal ligament (PDL) fibers and resorption areas. In groups I and II, presence of PDL fibers and absence of resorption were observed in all cases (100%), while all specimens (100%) of group III showed no PDL fibers and resorption areas. In conclusion, there are morphological differences in the apical region of primary teeth with different pulpal and periapical pathologies.

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Objective: To assess the influence of energy and pulse repetition rate of Er:YAG laser on the enamel ablation ability and substrate morphology. Methods: Fifteen crowns of molars were sectioned in four fragments, providing 60 samples, which were ground to flatten the enamel surface. The initial mass was obtained by weighing the fragments. The specimens were hydrated for I h, fixed, and a 3-mm-diameter area was delimited. Twelve groups were randomly formed according to the combination of laser energies (200, 250, 300, or 350 mJ) and pulse repetition rates (2, 3, or 4 Hz). The final mass was obtained and mass loss was calculated by the difference between the initial and final mass. The specimens were prepared for SEM. Data were submitted to ANOVA and Scheffe test. Results: The 4 Hz frequency resulted in higher mass loss and was statistically different from 2 and 3 Hz (p < 0.05). The increase of frequency produced more melted areas, cracks, and unselective and deeper ablation. The 350 mJ energy promoted greater mass loss, similar to 300 mJ. Conclusions: The pulse repetition rate influenced more intensively the mass loss and morphological alteration. Among the tested parameters, 350 mJ/3 Hz improved the ability of enamel ablation with less surface morphological alterations. (C) 2007 Wiley Periodicals, Inc. J Biomed Mater Res.

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Due to the major role of Streptococcus mutans and Streptococcus sobrinus in the etiology of dental caries, it is important to use culture media that allow for differentiating these bacterial species. The aim of this study was to evaluate the suitability of a modified SB-20 culture medium (SB-20M) for the isolation and morphological differentiation of S. mutans and S. sobrinus, compared to biochemical identification (biotyping). Saliva samples were collected using the spatula method from 145 children, seeded on plates containing the SB-20M, in which sucrose was replaced by coarse granular cane sugar, and incubated in microaerophilia at 37 degrees C during 72 h. Identification of the microorganisms was performed under stereomicroscopy based on colony morphology of 4904 colonies. The morphological identification was examined by biochemical tests of 94 randomly selected colonies with the macroscopic characteristic of S. mutans and S. sobrinus using sugar fermentation, resistance to bacitracin and production of hydrogen peroxide. There was no statistically significant difference (p> 0.05) between morphological identification in the SB-20M medium and biochemical identification (biotyping). Biotyping confirmed that S. mutans and S. sobrinus colonies were correctly characterized in the SB-20M in 95.8% and 95.5% of the cases, respectively. Of the mutans streptococci detected in the children 98% were S. mutans and 2% S. sobrinus. The SB-20M medium is reliable for detection and direct morphological identification of S. mutans and S. sobrinus. (C) 2010 Elsevier GmbH. All rights reserved.

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Aims: The study evaluated the influence of light curing units and immersion media on superficial morphology and chemistry of the nanofilled composite resin Supreme XT (3M) through the EDX analysis and SEM evaluation. Light curing units with different power densities and mode of application used were XL 3000 (480 mW/cm(2)), Jet Lite 4000 Plus (1230mW/cm(2)), and Ultralume Led 5 (790 mW/cm(2)) and immersion media were artificial saliva, Coke(R), tea and coffee, totaling 12 experimental groups. Specimens (10 mm X 2 mm) were immersed in each respective Solution for 5 min, three times a day, during 60 days and stored in artificial saliva at 37 degrees C +/- 1 degrees C between immersion periods. Topography and chemical analysis was qualitative. Findings: Groups immersed in artificial saliva, showed homogeneous degradation of matrix and deposition of calcium at the material surface. Regarding coffee, there was a reasonable chemical degradation with loss of load particles and deposition of ions. For tea, superficial degradation occurred in specific areas with deposition of calcium, carbon. potassium and phosphorus. For Coke(R), excessive matrix degradation and loss of load particles with deposition of calcium, sodium, and potassium. Conclusion: Light curing units did not influence the superficial morphology of composite resin tested, but the immersion beverages did. Coke(R) affected material`s surface more than did the other tested drinks. Microsc. Res. Tech. 73:176-181, 2010. (c) 2009 Wiley-Liss Inc.

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Anopheles albertoi Unti and Anopheles arthuri Unti are revived from the synonymy with Anopheles strodei Root, and a distinct morphological form (designated in this study as Anopheles CP Form) from the Strodei Complex of Anopheles (Nyssorhynchus) is characterized. The male genitalia of An. arthuri and An. albertoi are described and illustrated for the first time. An. strodei, An. arthuri, and An. albertoi were first distinguished based on scanning electron microphotos of the eggs, and then each egg type was associated with diagnostic characters of the male genitalia. Identification of Anopheles CP Form was based on morphological characters of the male genitalia, characterized and illustrated in this study. Molecular phylogenetic analysis was most clear when an outgroup was not included, in which case using the nuclear white gene, or the white gene in combination with the mitochondrial cytochrome c oxidase subunit I (COI) gene, clearly separated these four taxa. When Anopheles quadrimaculatus Say and Anopheles stephensi Liston were included as an outgroup, combined white and COI data resolved An. strodei and An. albertoi, whereas An. arthuri was not well resolved. The single sequence of Anopheles CP Form was recovered well separated from other groups in all analyses.

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This paper demonstrates the oscillatory characteristics of electrical signals acquired from two ornamental plant types (Epipremnum pinnatum and Philodendron scandens - Family Araceae), using a noninvasive acquisition system. The electrical signal was recorded using Ag/AgCl superficial electrodes inside a Faraday cage. The presence of the oscillatory electric generator was shown using a classical power spectral density. The Lempel and Ziv complexity measurement showed that the plant signal was not noise despite its nonlinear behavior. The oscillatory characteristics of the signal were explained using a simulated electrical model that establishes that for a frequency range from 5 to 15 Hz, the oscillatory characteristic is higher than for other frequency ranges. All results show that non-invasive electrical plant signals can be acquired with improvement of signal-to-noise ratio using a Faraday cage, and a simple electrical model is able to explain the electrical signal being generated. (C) 2010 Elsevier B.V. All rights reserved.

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We studied superclusters of galaxies in a volume-limited sample extracted from the Sloan Digital Sky Survey Data Release 7 and from mock catalogues based on a semi-analytical model of galaxy evolution in the Millennium Simulation. A density field method was applied to a sample of galaxies brighter than M(r) = -21+5 log h(100) to identify superclusters, taking into account selection and boundary effects. In order to evaluate the influence of the threshold density, we have chosen two thresholds: the first maximizes the number of objects (D1) and the second constrains the maximum supercluster size to similar to 120 h(-1) Mpc (D2). We have performed a morphological analysis, using Minkowski Functionals, based on a parameter, which increases monotonically from filaments to pancakes. An anticorrelation was found between supercluster richness (and total luminosity or size) and the morphological parameter, indicating that filamentary structures tend to be richer, larger and more luminous than pancakes in both observed and mock catalogues. We have also used the mock samples to compare supercluster morphologies identified in position and velocity spaces, concluding that our morphological classification is not biased by the peculiar velocities. Monte Carlo simulations designed to investigate the reliability of our results with respect to random fluctuations show that these results are robust. Our analysis indicates that filaments and pancakes present different luminosity and size distributions.

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Actinocephalus exhibits perhaps more diversity in habit than any other genus of Eriocaulaceae. This variation is largely a result of differences in the arrangement of the paraclades. Based on the analysis of stem architecture of all 25 species of Actinocephalus, the following patterns were established: (1) leaf rosette, with no elongated axis, instead the axillary paraclades originating directly from the short aerial stem, (2) rosette axis continuing into an elongated axis with spirally arranged paraclades, (3) an elongated axis originating from a rhizome, with ramified paraclades, and (4) an elongated axis originating from a short aerial stem, with paraclades arranged in a subwhorl. The elongated axis exhibits indeterminate growth only in pattern 4. Patterns 3 and 4 are found exclusively in Actinocephalus; pattern I occurs in many other genera of Eriocaulaceae, while pattern 2 is also found in Syngonanthus and Paepalanthus. Anatomically, each stem structure (i.e., paraclade, elongated axis, short aerial stem, rhizome) is thickened in a distinctive way and this can be used to distinguish them. Specifically, elongated axes and paraclades lack thickening, thickening of short aerial stems results from the primary thickening meristem and/or the secondary thickening meristem. Thickening of rhizomes results from the activity of the primary thickening meristem. (c) 2008 Elsevier GmbH. All rights reserved.

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Gracilaria tenuistipitata, a species of commercial interest, is becoming a model organism for studies on red algal physiology and molecular biology as it can be grown easily in vitro under a broad range of conditions. Most of the experiments carried out around the world have been based on a tetrasporophytic clone isolated in our laboratory from a specimen collected in China. Here we describe the life history of this species, give anatomic details of the reproductive structures, illustrate the morphological variability of tetraspore progeny and compare the growth rate of gametophytic and sporophytic thalli. Tetrasporophytic branches showed higher growth rates than gametophytic branches.

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Laurencia marilzae is recorded for the first time from the western Atlantic Ocean; it was found in Laje de Santos Marine State Park, Sao Paulo, southeastern Brazil. The specimens were collected in the rocky subtidal zone from 7 to 15 m depth. The most distinctive characteristic of this species is the presence of corps en cerise in all cells of the thallus, including cortex, medulla, and trichoblasts. The phylogenetic position of the species was inferred by analysis of the chloroplast-encoded rbcL gene sequences from 43 taxa, using two other rhodomelacean taxa and two members of the Ceramiaceae as outgroups. Within the Laurencia assemblage, L. marilzae from Brazil and from the Canary Islands ( type locality) formed a distinctive lineage sister to all other Laurencia species analyzed. Male plants are described for the first time. This study expands the geographical distribution of L. marilzae to the western Atlantic Ocean.

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Palisada flagellifera (Ceramiales, Rhodophyta) is recorded for the first time in the eastern Atlantic Ocean off Tenerife, La Gomera, La Palma and Fuerteventura, Canary Islands, Spain. The specimens were collected in 2006-2009 growing from the lower intertidal to subtidal zones to 2 m depth at sites exposed to wave action. The species possesses a palisade-like arrangement of cortical cells in cross section, lacks secondary pit connections between them, and has tetrasporangia produced by three fertile pericentral cells (the third and the fourth additional and the second that becomes fertile), and a right-angled arrangement of tetrasporangia. Gametangia were not observed. The phylogenetic relationships were inferred by analyses of the chloroplast-encoded rbcL gene sequences from 46 taxa. The Canarian and Brazilian P. flagellifera specimens formed a highly supported clade with a low level of genetic variation in the rbcL sequences (0.02-0.04%), confirming that they are the same taxonomic entity. This study expands the geographical distribution of P. flagellifera to the eastern Atlantic Ocean.