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Gradual Transition (gradual + transition)
Selected AbstractsShort-term plasticity in children's speech motor systemsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 8 2006Bridget Walsh Abstract Speech production is a highly skilled behavior that requires rapid and coordinated movements of the orofacial articulators. Previous studies of speech development have shown that children have more variable articulatory movements compared to adults, and cross-sectional studies have revealed that a gradual transition to more stable movement patterns occurs with age. The focus of the present investigation is on the potential role of short-term changes in speech motor performance related to practice. Thus we developed a paradigm to examine the influences of phonological complexity and practice on children (9 and 10-year-olds) and adults' production of novel nonwords. Using two indices that reflect the degree of trial-to-trial consistency of articulatory movements, we analyzed the first and last five productions of the novel nonwords. Both children and adults accurately produced the novel nonwords; however, children showed a practice effect; their last five trials were more consistently produced than their first five trials. Adults did not show this practice effect. This study provides new evidence that children show short-term changes in their speech coordinative patterns with practice. In addition, the present findings support the contribution of neuromotor noise or background, inherent variability to speech motor development. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 660,674, 2006. [source] The Optimal Grain Sized Nanocrystalline Ni with High Strength and Good Ductility Fabricated by a Direct Current Electrodeposition,ADVANCED ENGINEERING MATERIALS, Issue 6 2008X. Shen In this work, six pure Ni specimen which mean grain sizes spans a broad range from ultra-fine to nanometer were fabricated by direct current electrodeposition and a coarse grain Ni was obtained by annealing. A gradual transition of the crystallographic preferred orientation of the deposited Ni from (200) texture to isotropic or random orientation with decreasing the mean grain size was revealed by XRD. [source] Origin and geochemistry of Miocene marine evaporites associated with red beds: Great Kavir Basin, Central IranGEOLOGICAL JOURNAL, Issue 1 2007Hossain Rahimpour-Bonab Abstract During the Cenozoic numerous shallow epicontinental evaporite basins formed due to tectonic movements in the Northern Province of the Central Iran Tectonic Zone (the Great Kavir Basin). During the Miocene, due to sea-level fluctuations, thick sequences of evaporites and carbonates accumulated in these basins that subsequently were overlain by continental red beds. Development of halite evaporites with substantial thickness in this area implies inflow of seawater along the narrow continental rift axis. The early ocean basin development was initiated in Early Eocene time and continued up to the Middle Miocene in the isolated failed rift arms. Competition between marine and non-marine environments, at the edge of the encroaching sea, produced several sequences of both abrupt and gradual transition from continental wadi sediments to marginal marine evaporites in the studied area. These evaporites show well-preserved textures indicative of relatively shallow-brine pools. The high Br content of these evaporites indicates marine-derived parent brines that were under the sporadic influence of freshening by meteoric water or replenishing seawater. However, the association of hopper and cornet textures denotes stratified brine that filled a relatively large pool and prevented rapid variations in the Br profile. Unstable basin conditions that triggered modification of parent brine chemistry prevailed in this basin and caused variable distribution patterns for different elements in the chloride units. The presence of sylvite and the absence of Mg-sulphate/chlorides in the paragenetic sequence indicate SO4,depleted parent brine in the studied sequence. Petrographic examinations along with geochemical analyses on these potash-bearing halites reveal parental brines which were a mixture of seawater and CaCl2 -rich brines. The source of CaCl2 -rich brines is ascribed to the presence of local rift systems in the Great Kavir Basin up to the end of the Early Miocene. Copyright © 2007 John Wiley & Sons, Ltd. [source] Lipomatous mixed tumor with follicular differentiation of the skinJOURNAL OF CUTANEOUS PATHOLOGY, Issue 5 2006Satomi Kasashima A very rare case of cutaneous mixed tumor with numerous adipose tissue and hair follicular structures in a 67-year-old Japanese male was reported. A well-circumscribed tumor was in the subcutaneous tissue of the cheek and far from the parotid gland. Histologically, the tumor consisted of an admixture of the adipose tissue, fibromyxoid tissue with spindle cells, and branching tubular structures. Outer layers of ductal epithelial cells and single spindle cells were often in a transition, likely as typical mixed tumor. Branching ducts connected with keratinous cysts, strands of trichoblastic basophilic cells and clear cell nests. There was a gradual transition, between small-sized adipocytes and vacuolated spindle cells. No chondroid stroma was seen. To our knowledge, this tumor is the first case of a lipomatous mixed tumor with hair follicular differentiation. The case indicates an additional wide spectrum of histologic appearances of cutaneous mixed tumor. [source] Origin of migmatites by deformation-enhanced melt infiltration of orthogneiss: a new model based on quantitative microstructural analysisJOURNAL OF METAMORPHIC GEOLOGY, Issue 1 2008P. HASALOVÁ Abstract A detailed field study reveals a gradual transition from high-grade solid-state banded orthogneiss via stromatic migmatite and schlieren migmatite to irregular, foliation-parallel bodies of nebulitic migmatite within the eastern part of the Gföhl Unit (Moldanubian domain, Bohemian Massif). The orthogneiss to nebulitic migmatite sequence is characterized by progressive destruction of well-equilibrated banded microstructure by crystallization of new interstitial phases (Kfs, Pl and Qtz) along feldspar boundaries and by resorption of relict feldspar and biotite. The grain size of all felsic phases decreases continuously, whereas the population density of new phases increases. The new phases preferentially nucleate along high-energy like,like boundaries causing the development of a regular distribution of individual phases. This evolutionary trend is accompanied by a decrease in grain shape preferred orientation of all felsic phases. To explain these data, a new petrogenetic model is proposed for the origin of felsic migmatites by melt infiltration from an external source into banded orthogneiss during deformation. In this model, infiltrating melt passes pervasively along grain boundaries through the whole-rock volume and changes completely its macro- and microscopic appearance. It is suggested that the individual migmatite types represent different degrees of equilibration between the host rock and migrating melt during exhumation. The melt topology mimicked by feldspar in banded orthogneiss forms elongate pockets oriented at a high angle to the compositional banding, indicating that the melt distribution was controlled by the deformation of the solid framework. The microstructure exhibits features compatible with a combination of dislocation creep and grain boundary sliding deformation mechanisms. The migmatite microstructures developed by granular flow accompanied by melt-enhanced diffusion and/or melt flow. However, an AMS study and quartz microfabrics suggest that the amount of melt present did not exceed a critical threshold during the deformation to allow free movements of grains. [source] Gallbladder adenocarcinoma arising in Rokitansky,Aschoff sinusPATHOLOGY INTERNATIONAL, Issue 12 2008Tadashi Terada Carcinoma arising from Rokitansky,Aschoff sinus (RAS) is extremely rare; only eight cases have been reported in the literature. Herein is reported a case of minute adenocarcinoma arising in RAS. A 77-year-old Japanese man with gallbladder stones underwent cholecystectomy. A tiny submucosal tumor (1 cm × 1 cm) was incidentally recognized. Histologically, the submucosal tumor was located in the subserosa and, to a lesser extent, in the fibromuscular layer. It was adenocarcinoma. RAS were recognized within the tumor, and there was a gradual transition between RAS and the adenocarcinoma. Mucin histochemistry indicated neutral and acidic mucins in the cytoplasm and lumens of the adenocarcinoma cells. Immunohistochemistry showed that the adenocarcinoma cells were positive for cytokeratin, epithelial membrane antigen, carbohydrate antigen 19-9, K-i67 (labeling = 80%), MUC1, MUC5AC and MUC6. In contrast, the adenocarcinoma cells were negative for CEA, c-erbB2, p53 protein, MUC2 and CD10. In summary, minute subserosal adenocarcinoma, which arose in RAS, was found incidentally; therefore careful examination of resected gallbladders is necessary. [source] The Development of Commodity Exchanges in the Former Soviet Union, Eastern Europe, and ChinaAUSTRALIAN ECONOMIC PAPERS, Issue 4 2001Anne E. Peck The virtual collapse of the centrally planned economies of the countries of the former Soviet Union (FSU) and the more gradual transition from central planning to a market-oriented economy in China were both accompanied by the opening of hundreds of exchanges trading many agricultural, resource, and other physical commodities. Although many viewed them as harbingers of full-fledged market-based economies, most of the new exchanges in fact have since closed either for lack of activity or by government intervention, a history that this paper documents. New exchanges faced numerous obstacles in sustaining interest, from developing standardised contract terms to establishing effective self-regulation and state regulatory oversight. In several countries, the transparency of transactions on exchanges attracted governments interested in collecting taxes and customs duties which only drove trade away from the exchanges or turned them into little more than state agencies. In China, regulators struggled with duplicative exchanges and products, price volatility, large speculative interest, and several manipulations and have recently reduced the number of exchanges to just three and severely limited the commodities traded. There have been some successes too, including (at least prospectively) the three remaining exchanges in China, the Budapest Commodity Exchange in Hungary, and the Poznan Commodity Exchange in Poland. For all, identifying the terms to create standardised contracts has been (and continues to be) a major challenge. [source] Quantitative steps in symbiogenesis and the evolution of homeostasisBIOLOGICAL REVIEWS, Issue 3 2003S. A. L. M. KOOIJMAN ABSTRACT The merging of two independent populations of heterotrophs and autotrophs into a single population of mixotrophs has occurred frequently in evolutionary history. It is an example of a wide class of related phenomena, known as symbiogenesis. The physiological basis is almost always (reciprocal) syntrophy, where each species uses the products of the other species. Symbiogenesis can repeat itself after specialization on particular assimilatory substrates. We discuss quantitative aspects and delineate eight steps from two free-living interacting populations to a single fully integrated endosymbiotic one. The whole process of gradual interlocking of the two populations could be mimicked by incremental changes of particular parameter values. The role of products gradually changes from an ecological to a physiological one. We found conditions where the free-living, epibiotic and endobiotic populations of symbionts can co-exist, as well as conditions where the endobiotic symbionts outcompete other symbionts. Our population dynamical analyses give new insights into the evolution of cellular homeostasis. We show how structural biomass with a constant chemical composition can evolve in a chemically varying environment if the parameters for the formation of products satisfy simple constraints. No additional regulation mechanisms are required for homeostasis within the context of the dynamic energy budget (DEB) theory for the uptake and use of substrates by organisms. The DEB model appears to be closed under endosymbiosis. This means that when each free-living partner follows DEB rules for substrate uptake and use, and they become engaged in an endosymbiotic relationship, a gradual transition to a single fully integrated system is possible that again follows DEB rules for substrate uptake and use. [source] Implications of a fossil stickleback assemblage for Darwinian gradualismJOURNAL OF FISH BIOLOGY, Issue 8 2009M. A. Bell Darwin postulated that a complete fossil record would contain numerous gradual transitions between ancestral and descendant species, but 150 years after publication of The Origin of Species, few such transitions have materialized. The fossil stickleback Gasterosteus doryssus and the deposit in which it occurs provide excellent conditions to detect such transitions. Abundant, well-preserved fossils occur in a stratigraphic setting with fine temporal resolution. The paleoecology of G. doryssus resembles the ecology of modern lakes that harbour the phenotypically similar three-spined stickleback Gasterosteus aculeatus. Gasterosteus aculeatus are primitively highly armoured, but G. doryssus comprised two contemporaneous biological species with relatively weak armour, including a near-shore, benthic feeder (benthic) and an offshore planktivore (limnetic). The benthic species expanded its range into the limnetic zone of the lake, where it apparently switched to planktivory and evolved reduced armour within c. 5000 years in response to directional selection. Although gradual evolution of mean phenotypes occurred, a single major gene caused much of evolutionary change of the pelvic skeleton. Thus, Darwin's expectation that transitions between species in the fossil record would be gradual was met at a fine time scale, but for pelvic structure, a well-studied trait, his expectation that gradual change would depend entirely on numerous, small, heritable differences among individuals was incorrect. [source] | |||||||||||||