bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal‐baric structure andP–Thistory of the Brooks Range metamorphic core, Alaska
Authors: Vogl J. J. 
Published: October 2010

AbstractDocumentation of pressure–temperature (P–T) histories across an epidote‐amphibolite facies culmination provides new insight into the tectono‐thermal evolution of the Brooks Range collisional orogen. Thermobarometry reveals that the highest grade rocks formed at peak temperatures of 560–600 °C and at pressures of 8–9.5 kbar. The thermal culmination coincides with the apex of a structural dome defined by oppositely dipping S2 crenulation cleavages suggesting post‐metamorphic doming. South of the thermal culmination, greenschist facies and lowermost epidote‐amphibolite facies rocks preserve widespread evidence for an early blueschist facies metamorphism. In contrast, no evidence for an early blueschist facies metamorphism was found in similar grade rocks of the northern flank, indicating that the southern flank underwent initial deeper burial during southward underthrusting of the continental margin. Thus, while the dome shows a symmetric distribution of peak temperatures, theP–Tpaths followed by the two flanks must have varied. This variation suggests that final thermal re‐equilibration to greenschist and epidote–amphibolite facies conditions did not result from a simple process of southward underthrusting followed by thermal re‐equilibration from the bottom upward. The new data are inconsistent with a previous model that invokes such re‐equilibration, along with northward thrusting of epidote–amphibolite facies rocks over lower grade rocks presently on the southern flank of the culmination, to produce an inverted metamorphic field gradient. Instead, it is suggested that following blueschist facies metamorphism, rocks of the southern and northern flanks were juxtaposed, during which time the more deeply buried south flank was partially emplaced above rocks to the north, where they escaped Albian epidote–amphibolite facies overprinting. Porphyroblast growth, which post‐dates the main fabric on the north flank of the culmination may be the result of Albian thermal re‐equilibration following this deformation. Post‐metamorphic doming resulted from a combination of Albian‐Cenomanian extension and Tertiary deformation.
The metamorphic evolution of metapelitic granulites from Radok Lake, northern Prince Charles Mountains, east Antarctica; evidence for an anticlockwise P–T path
Authors: Boger S. D. , White R. W. 
Published: October 2010

AbstractMineral textures in metapelitic granulites from the northern Prince Charles Mountains, coupled with thermodynamic modelling in the K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3 (KFMASHTO) model system, point to pressure increasing with increasing temperature on the prograde metamorphic path, followed by retrograde cooling (i.e. an anticlockwise P–T path). Textural evidence for the increasing temperature part of the path is given by the breakdown of garnet and biotite to form orthopyroxene and cordierite in sillimanite‐absent rocks, and through the break‐down of biotite and sillimanite to form spinel, cordierite and garnet in more aluminous assemblages. This is equated to the advective addition of heat from the regional emplacement of granitic and charnockitic magmas dated at c. 980 Ma. A subsequent increase in pressure, inferred from the break‐down of spinel and quartz to sillimanite, cordierite and garnet in aluminous rocks, is attributed to crustal thickening related to upright folding dated at 940–910 Ma. The terrane attained peak metamorphic temperatures of c. 880 °C at pressures of c. 6.0–6.5 kbar during this event. Subsequent cooling is inferred from the localised breakdown of cordierite and garnet to form biotite and sillimanite that developed in the latter stages of the same event. The textural observations described are interpreted via the application of P–T and P–T–X pseudosections. The latter show that most rock compositions preserve only fragments of the overall P–T path; a result of different rock compositions undergoing mineral assemblage changes, or changes in mineral modal abundance, on different sections of the P–T path. The results also suggest that partial melting during granulite facies metamorphism, coupled with melt loss and dehydration, initiated a switch from pervasive ductile, to discrete ductile/brittle deformation, during retrograde cooling.
Chemical and physical responses to deformation in micaceous quartzites from the Tauern Window, Eastern Alps
Authors: Selverstone J. , Hyatt J. 
Published: October 2010

AbstractMicaceous quartzites from a subvertical shear zone in the Tauern Window contain abundant quartz clasts derived from dismembered quartz‐tourmaline veins. Bulk plane strain deformation affected these rocks at amphibolite facies conditions. Shape changes suggest net shortening of the clasts by 11–64%, with a mean value of 35%. Quartz within the clasts accommodated this strain largely via dislocation creep processes. On the high‐stress flanks of the clasts, however, quartz was removed via solution mass transfer (pressure solution) processes; the resulting change in bulk composition allowed growth of porphyroblastic staurolite + chlorite ± kyanite on the clast flanks. Matrix SiO2 contents decrease from c. 83 wt% away from the clasts to 49–58% in the selvages on the clast flanks. The chemical changes are consistent with c. 70% volume loss in the high‐stress zones. Calculated shortening values within the clast flanks are similar to the volume‐loss estimates, and are greatly in excess of the shortening values calculated from the clasts themselves. Flow laws for dislocation creep versus pressure solution imply large strain‐rate gradients and/or differential stress gradients between the matrix and the clast selvages. In a rock containing a large proportion of semirigid clasts, weakening within the clast flanks could dominate rock rheology. In our samples, however, weakening within the selvages was self limiting: (1) growth of strong staurolite porphyroblasts in the selvages protected remaining quartz from dissolution; and (2) overall flattening of the quartz clasts probably decreased the resolved shear stress on the flanks to values near those of the matrix, which would have reduced the driving force for solution‐transfer creep. Extreme chemical changes nonetheless occurred over short distances. The necessity of maintaining strain compatibility may lead to significant localized dissolution in rocks containing rheologic heterogeneities, and overall weakening of the rocks may result. Solution‐transfer creep may be a major process whereby weakening and strain localization occur during deep‐crustal metamorphism of polymineralic rocks.
The metamorphic field gradient in the eclogite type locality, Koralpe region, Eastern Alps
Authors: Tenczer V. , Stüwe K. 
Published: October 2010

AbstractThe eclogite type locality in the Eastern Alps (the Koralpe and Saualpe region) is the largest region in the Eastern Alps that preserves high‐pressure metamorphic rocks from the Eo‐Alpine orogenic event of the Cretaceous age. Thermobarometric data from the metapelitic gneisses in the region indicate that a metamorphic field gradient across the region can be divided into three parts. The northern part shows continuously increasing P–T from 10 ± 1.5 to 14 ± 1.5 kbar and 500 ± 68 to 700 ± 68 °C over a distance of 40 km. The continuous increase in P–T indicates that no major tectonic boundaries were active in this part during the Eo‐Alpine orogeny. Small discontinuities in the pressure gradient of the northern part can be correlated with more localized deformation. The central part exposes amphibolite–eclogite facies rocks with 15 ± 1.5 kbar and 700 ± 68 °C over about 20 km length. The southern part shows decreasing P–T conditions from 15 ± 1.5 to 10 ± 1.5 kbar and 700 ± 68 to 600 ± 63 °C over a distance of 10 km beyond which conditions remain roughly constant for the remainder of the profile.Overall, the field gradient is characterized by: (i) an increase in age with decreasing metamorphic grade and (ii) a T/P ratio that is lower than common metamorphic geotherms. The age–grade relationship is consistent with the timing relationship along piezothermal arrays predicted by simple models for regional metamorphism. However, the T/P ratio of the field gradient is inconsistent with such an interpretation. These inconsistencies indicate that the profile is not simply an obliquely exposed crustal section. We suggest that the exhumation of the transect is best explained with a two dimensional model of an extruding wedge, as has recently been suggested as a typical scenario for other large scale compressional orogens.
Relating zircon and monazite domains to garnet growth zones: age and duration of granulite facies metamorphism in the Val Malenco lower crust
Authors: Hermann J. , Rubatto D. 
Published: October 2010

AbstractZircon from a lower crustal metapelitic granulite (Val Malenco, N‐Italy) display inherited cores, and three metamorphic overgrowths with ages of 281 ± 2, 269 ± 3 and 258 ± 4 Ma. Using mineral inclusions in zircon and garnet and their rare earth element characteristics it is possible to relate the ages to distinct stages of granulite facies metamorphism. The first zircon overgrowth formed during prograde fluid‐absent partial melting of muscovite and biotite apparently caused by the intrusion of a Permian gabbro complex. The second metamorphic zircon grew after formation of peak garnet, during cooling from 850 °C to c. 700 °C. It crystallized from partial melts that were depleted in heavy rare earth elements because of previous, extensive garnet crystallization. A second stage of partial melting is documented in new growth of garnet and produced the third metamorphic zircon. The ages obtained indicate that the granulite facies metamorphism lasted for about 20 Myr and was related to two phases of partial melting producing strongly restitic metapelites.Monazite records three metamorphic stages at 279 ± 5, 270 ± 5 and 257 ± 4 Ma, indicating that formation ages can be obtained in monazite that underwent even granulite facies conditions. However, monazite displays less clear relationships between growth zones and mineral inclusions than zircon, hampering the correlation of age to metamorphism. To overcome this problem garnet–monazite trace element partitioning was determined for the first time, which can be used in future studies to relate monazite formation to garnet growth.
Effect of denture cleansers, surface finish, and temperature on Molloplast B resilient liner color, hardness, and texture
Authors: Tan Han‐Kuang , Woo Andrew , Kim Silvia , Lamoureux Michael , Grace Michael 
Published: October 2010

Purpose The purpose of this study was to compare color, texture, and Shore A hardness of a resilient silicone denture liner with as‐polymerized, roughened, or pumiced surfaces after treatment with perborate‐, persulfate‐, or hypochlorite‐containing denture cleansers at 25° or 55°.Materials and Methods Fifty‐eight specimens that each exhibited an as‐polymerized, a roughened, and a pumiced area were exposed to 5 different commercially available perborate‐, persulfate‐, or hypochlorite‐containing denture cleansers at 25° or 55° continuously for 4 ½ months. The solutions were replaced twice a day. Control specimens were soaked in water with no cleanser. Before and after the 4 ½–month cleaning regimen, the color, hardness, and texture of resilient liner surfaces were evaluated using a color densitometer, a Shore A durometer (Shore Instrument & Mfg Co, Freeport, NY), and a surface profilometer, respectively. Differences among groups after the cleanser treatment were determined using a repeated measures analysis of variance (α= 0.05) and a Tukey's Honestly Significant Difference post hoc test.Results Roughened specimen surfaces after 25° or 55° cleanser treatment exhibited significant color loss with some perborate‐containing cleansers compared with the control. Roughened specimens treated at 55° with perborate‐containing cleansers also exhibited significantly greater color loss than those treated with the persulfate‐containing cleanser. With roughened surfaces, significantly greater hardness was found with some perborate‐containing cleanser compared with a hypochlorite‐containing cleanser after treatment at 25°. No differences were observed in surface texture based upon cleanser treatment.Conclusion After silicone resilient denture liner treatment with certain perborate‐containing denture cleansers, a greater amount of components could leach from the liner leading to a loss of color if the liner surface is rough.
Interchangeability of semiadjustable articulators after 2 to 7 years of use
Authors: Price Richard B.T. , Loney Robert W. , Andreou Pantelis 
Published: October 2010

Purpose The purpose of this study was to test the interchangeability of articulators that had been in use from 2 to 7 years and compare these results with the interchangeability of the same articulators 1 year earlier.Materials and Methods Forty‐six Whip Mix model #2240 articulators (Whip Mix Corporation, Louisville, KY) that were in clinical use from 2 to 7 years were checked for interchangeability using the Whip Mix #2245 check system. The horizontal tolerance of the check system was 94 μm. Articulators were also evaluated in the vertical dimension at 4 predetermined locations around the check system cylinders using 26‐μm—thick shimstock. Vertical discrepancies between the cylinders were recorded as the thickness of 0, 1, 2, or more than 2 pieces of shimstock. Interchangeability results were compared with those determined 1 year previously using the same evaluation methods using the Exact McNemar's Test of Agreement (α= 0.05).Results Using the Whip Mix 2245 check system, 35 (76%) articulators were interchangeable after 2 to 7 years of use. This compares to 38 (83%) that were interchangeable upon evaluation 1 year earlier. The decrease in interchangeability was not significant (p= .4531). Forty‐three (94%) of the articulators had vertical discrepancies of 52 μm or less at the initial evaluation. One year later, 45 (98%) of the articulators had vertical discrepancies of 52 μm or less. After 1 year, there were significant differences in the amount of vertical space between the cylinders only at the right side (p= .014).Conclusion The Whip Mix model #2240 articulator can remain interchangeable during clinical use for 7 years, but should be routinely checked for calibration.
Dimensional accuracy of dental casts: Influence of tray material, impression material, and time
Authors: Thongthammachat Sudsukh , Moore B. Keith , Barco M. Thomas , Hovijitra Suteera , Brown David T. , Andres Carl J. 
Published: October 2010

Purpose This study evaluated the influence on dimensional accuracy of dental casts made with different types of trays and impression materials and poured at different and multiple times.Materials and Methods Two types of stock trays (plastic stock tray, perforated metal stock tray) and 4 types of custom tray materials (autopolymerizing acrylic resin, thermoplastic resin, and 2 types of light‐polymerized acrylic resins) were used with 2 types of impression materials (addition polymerizing silicone and polyether), to make impressions of a metal master model. Each tray and impression material was used to make 5 impressions. Casts were made by multiple pourings at 30 minutes, 6 hours, 24 hours, and 30 days after impression making. Using a measuring microscope, 12 distances were calculated based on measurements of 8 reference points. The absolute value of the difference of each measurement was calculated, as was the corresponding measurement on the master model. A Bayesian model using a simple noninformative prior was used to analyze these data.Results Statistical differences within 6 μm were found only with thermoplastic resin tray material for addition silicone, and for thermoplastic resin tray material and 1 type of light‐polymerized acrylic resin for polyether. Neither stock trays nor custom trays contributed to the differences in accuracy of the casts. All deviations in casts made with silicone impression material were within a clinically acceptable range. For the polyether, distortions occurred that were clinically unacceptable. Impressions made from polyether distorted over time. Silicone impression material has dimensional stability up to 30 days.Conclusion Accurate casts can be made with either stock trays or custom trays. An impression made from polyether should be poured only once and within 24 hours after impression making, because of the distortion of the material over time. Silicone impression material has better dimensional stability than polyether.
Modulated bone matrix‐related gene expression is associated with differences in interfacial strength of different implant surface roughness
Authors: Ogawa Takahiro , Sukotjo Cortino , Nishimura Ichiro 
Published: October 2010

Purpose The objective of this study was to examine the effect of implant surface topography on biomechanical strength and expression patterns of bone extracellular matrix (ECM)‐related genes during implant healing.Materials and Methods Cylinder implants with turned or dual acid‐etched (DE) surface were placed into the femurs of female Sprague‐Dawley rats. At 2 and 4 weeks after the implantation, the implant push‐in test was performed to measure the load‐bearing strength of the bone‐tissue interface. T‐shaped hollow implants were separately placed and the total RNA was extracted from the ingrown tissue within the hollow chamber. The RNA was subjected to reverse transcriptase polymerase chain reaction to analyze the expression pattern of selected bone extracellular matrix‐related genes.Results The push‐in value of the DE implant is approximately 300% greater than that of the turned implant at weeks 2 and 4 (p=.0090). The expression of collagen II, osteocalcin and biglycan was higher in the week 2 DE implant group than the turned implant group. At week 4 the expression of collagen II and IX was 7‐ and 26‐fold, respectively, greater in the DE implant group than in the turned implant group.Conclusions The surface topography of implants may induce the phenotypic alteration of wound healing cells. The increased interfacial strength of the DE implant may be associated with the modulated expression of the selected set of bone extracellular matrix genes.
Preclinical complete dentures curriculum survey
Authors: Rashedi Behnoush , Petropoulos Vicki C. 
Published: October 2010

Purpose A survey of U.S. dental schools was conducted in 2001 to determine the curricular structure, teaching philosophies, and techniques used in preclinical complete denture courses.Materials and Methods The questionnaire was mailed to the chairperson of the prosthodontic/restorative departments of 54 U.S. dental schools. Of these, 43 schools returned the completed survey, a response rate of 80%. The mean, median, and range of responses were computed where applicable.Results Results from this survey show that the mean student‐to‐faculty ratio in the preclinical course was 12:1, with a median of 12:1 and a range of 6:1 to 27:1. The mean number of laboratory hours was 74, with a median of 70.5 and a range of 31.5 to 160. The mean number of lecture hours reported was 28, with a median of 25 and a range 12 to 80. The mean number of practical examinations was 3, with a median of 3 and a range of 0 to 11. Eighty‐four percent of the schools have prosthodontists teaching the course. The mean number of months that this course is taught is 5 months, with a median of 5 and a range of 2 to 13. Fifty‐eight percent of the schools use the Hanau semiadjustable articulator. Sixty‐five percent of the schools use protrusive records to set the articulator. The facebow preservation record is used by 84% of the schools.Conclusions Preclinical complete denture educational programs vary from school to school, yet a large percentage of schools agree on certain topics. Only 28% of dental schools are incorporating new technologies, such as the internet, in their preclinical complete denture curriculum. Nineteen percent of dental schools are using only the Portrait denture teeth, which are newer than the Bioblend and Bioform teeth.
Linguistic Self‐Correction in the Absence of Feedback: A New Approach to the Logical Problem of Language Acquisition
Authors: Ramscar Michael , Yarlett Daniel 
Published: October 2010

AbstractIn a series of studies children show increasing mastery of irregular plural forms (such as mice) simply by producing erroneous over‐regularized versions of them (such as mouses). We explain this phenomenon in terms of successive approximation in imitation: Children over‐regularize early in acquisition because the representations of frequent, regular plural forms develop more quickly, such that at the earliest stages of production they interfere with children's attempts to imitatively reproduce irregular forms they have heard in the input. As the strength of the representations that determine children's productions settle asymptotically, the early advantage for the frequent regular forms is negated, and children's attempts to imitate the irregular forms they have observed become more likely to succeed (a process that produces the classic U‐shape in children's acquisition of plural inflection). These data show that children can acquire correct linguistic behavior without feedback in a situation where, as a result of philosophical and linguistic analyses, it has often been argued that it is logically impossible for them to do so.
Foundations of Representation: Where Might Graphical Symbol Systems Come From?
Authors: Garrod Simon , Fay Nicolas , Lee John , Oberlander Jon , MacLeod Tracy 
Published: October 2010

AbstractIt has been suggested that iconic graphical signs evolve into symbolic graphical signs through repeated usage. This article reports a series of interactive graphical communication experiments using a ‘pictionary’ task to establish the conditions under which the evolution might occur. Experiment 1 rules out a simple repetition based account in favor of an account that requires feedback and interaction between communicators. Experiment 2 shows how the degree of interaction affects the evolution of signs according to a process of grounding. Experiment 3 confirms the prediction that those not involved directly in the interaction have trouble interpreting the graphical signs produced in Experiment 1. On the basis of these results, this article argues that icons evolve into symbols as a consequence of the systematic shift in the locus of information from the sign to the users' memory of the sign's usage supported by an interactive grounding process.
Mnemonic Context Effect in Two Cultures: Attention to Memory Representations?
Authors: Duffy Sean , Kitayama Shinobu 
Published: October 2010

AbstractIn two experiments we demonstrate a substantial cross‐cultural difference in a mnemonic context effect, whereby a magnitude estimate of a simple stimulus such as a line or circle is biased toward the center of the distribution of previously seen instances of the same class. In support of the hypothesis that Asians are more likely than Americans to disperse their attention to both the target stimulus and its mnemonic context, this effect was consistently larger for Japanese than for Americans. Moreover, the cultural difference was attenuated by an experimentally induced belief in class homogeneity that augmented the context effect itself in both cultures. More important, these belief effects happened in the absence of any objective change in stimulus distribution. Implications for sociocultural shaping of cognition are discussed.