A reappraisal of peridotite solidus phase equilibria from 6 to 14 GPa in the system CaO-MgO-Al2O3-SiO2

2021 ◽  
Author(s):  
Shantanu Keshav ◽  
Gudmundur H Gudfinnsson
Keyword(s):  
Crystalline Phase ◽  
Fusion Reaction ◽  
Lanthanum Chromite ◽  
Phase Assemblage ◽  
Composition Space ◽  
Single Temperature ◽  
Partial Fusion ◽  
Invariant Points ◽  
Future Work ◽  
Clapeyron Slope

Abstract Experimentally determined isobaric invariant melting phase relations from 6 to 14 GPa in the system CaO-MgO-Al2O3-SiO2 (CMAS), involving the crystalline phases, forsterite + orthopyroxene + clinopyroxene + garnet, and liquid, are reported. Experiments were conducted using a multianvil device with stepped lanthanum chromite heaters in the pressure cells. At a fixed pressure, the five-phase assemblage identified above can exist only at a single temperature. As such, these isobaric invariant points correspond to the solidus of model garnet peridotite in this part of the composition space in the studied system, as is the case at lower pressures in some previous studies. The solidus of model peridotite is univariant in pressure-temperature space, has a positive Clapeyron slope, and the isobaric invariant solidus temperatures, at, 6, 8, 10, 12, and 14 GPa, are, 1965oC, 2090oC, 2200oC, 2280oC, and 2320oC, respectively. Over the investigated pressure range, orthopyroxene is in reaction relation with the liquid, with the fusion reaction taking the form, forsterite + clinopyroxene + garnet = orthopyroxene + liquid. The compositions of liquids in the experiments reported here do not seem to depend on orthopyroxene being present in the experiments. Compositionally, liquids here are quite magnesian and siliceous, and have lower alumina and lime concentrations than at lower pressures with the identical crystalline phase assemblage in the system CMAS. In contrast to some previous studies, in this work, there is evidence neither of maximum and minimum normative forsterite concentration of the isobaric invariant liquid at around 8 GPa and 12 GPa, respectively, nor of a substantial curvature in the track of liquid compositions, when such liquids coexist with the mentioned four-phase crystalline phase assemblage. Instead, here, with increasing pressure from 6 to 14 GPa, liquids at the isobaric invariant points (defining the univariant solidus) become progressively (quasi-linearly) enstatite-normative. This experimental observation on liquid compositions from the present study might be important for future work directed at attempting to investigate chemistry of liquids derived from partial fusion of anhydrous peridotite at pressures, and corresponding depths in Earth, greater than investigated here.

scholarly journals Effect of crystalline phase assemblage on reliability of 3Y-TZP

2020 ◽  
Author(s):  
Isabelle Denry ◽  
Maged Abdelaal ◽  
Deborah V. Dawson ◽  
Julie A. Holloway ◽  
John Robert Kelly
Keyword(s):  
Crystalline Phase ◽  
Phase Assemblage

scholarly journals Evidence that Rabies Virus Forms Different Kinds of Fusion Machines with Different pH Thresholds for Fusion

2004 ◽  
Vol 78 (16) ◽  
pp. 8746-8752 ◽  
Author(s):  
Stéphane Roche ◽  
Yves Gaudin
Keyword(s):  
Rabies Virus ◽  
Early Stage ◽  
Fusion Reaction ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Low Ph ◽  
Viral Glycoprotein ◽  
Glycoprotein G ◽  
Partial Fusion ◽  
Ph Conditions

ABSTRACT Fusion of rabies virus with membranes is triggered at a low pH and is mediated by a viral glycoprotein (G). Fusion of rabies virus with liposomes was monitored by using a lipid mixing assay based on fluorescence resonance energy transfer. Fusion was detected below pH 6.4, and its extent increased with H+ concentrations to be maximal around pH 6.15. The origin of the partial fusion activity of rabies virus under suboptimal pH conditions (i.e., between pH 6.15 and 6.4) was investigated. We demonstrate unambiguously that fusion at a suboptimal pH is distinct from the phenomenon of low-pH-induced inactivation and that it is not due to heterogeneity of the virus population. We also show that viruses that do not fuse under suboptimal pH conditions are indeed bound to the target liposomes and that the fusion complexes they have formed are blocked at an early stage of the fusion pathway. Our conclusion is that along the fusion reaction, different kinds of fusion machines with different pH thresholds for fusion can be formed. Possible explanations of this difference of pH sensitivity are discussed.

The join CaMgSi2O6-Ca2MgSi2O7-CaTiAl2O6 in the system CaO-MgO-Al2O3-TiO2-SiO2 and its bearing on titanpyroxenes

1971 ◽  
Vol 38 (296) ◽  
pp. 471-480 ◽  
Author(s):  
Kosuke Onuma ◽  
Kenzo Yagi
Keyword(s):  
Solid Solution ◽  
Phase Equilibrium ◽  
Solid Solutions ◽  
Phase Assemblage ◽  
Final Phase ◽  
Rich Region ◽  
Poor Region ◽  
Three Phase ◽  
Invariant Points

SummaryThe phase equilibrium diagrams of CaMgSi2O6-CaTiAl2O6 with 10, 20, and 30 wt % Ca2MgSi2O7 in the join CaMgSi2O6-Ca2MgSi2O7-CaTiAl2O6 were determined. Six three-phase assemblages, six four-phase assemblages, and two five-phase assemblages (isobaric trivariant, divariant, and univariant) were confirmed. The univariant assemblages are diopsidess+forsterite+åkermanitess + perovskite + liquid and diopsidess+åkermanitess+perovskite+spinel + liquid. Because of the complex solid solutions of diopside and åkermanite the crystallization ceases before invariant assemblages are reached and the final phase assemblage in the diopside-rich region is diopsidess+åkermanitess+perovskite, in the diopside-poor region diopsidess+åkermanitess+perovskite + spinel. Two invariant points, diopsidess+forsterite+åkermanitess+perovskite+spinel+liquid and diopsidess+åkermanitess+anorthite+perovskite+spinel+liquid in the silica-poor region of the system CaO-MgO-Al2O3-TiO2-SiO2 are estimated. The diopside solid solution in this join is discussed with its bearing on the natural titanpyroxenes from alkalic rocks including melilite.

Present status of radio astrometry with baselines ≤ 35 km

1978 ◽  
Vol 48 ◽  
pp. 175-178 ◽  
Author(s):  
K. J. Johnston
Keyword(s):  
Present Status ◽  
Future Work

A summary of results for radio astrometry with baselines ≤ 35 km and priorities for future work are given.

A Phonomotor Approach to Apraxia of Speech Treatment

2020 ◽  
Vol 29 (4) ◽  
pp. 2109-2130
Author(s):  
Lauren Bislick
Keyword(s):  
Phase I ◽  
Treatment Effects ◽  
Single Case ◽  
Motor Planning ◽  
The Other ◽  
Multimodal Approach ◽  
Apraxia Of Speech ◽  
Duration Of Treatment ◽  
Treatment Gains ◽  
Future Work

Purpose This study continued Phase I investigation of a modified Phonomotor Treatment (PMT) Program on motor planning in two individuals with apraxia of speech (AOS) and aphasia and, with support from prior work, refined Phase I methodology for treatment intensity and duration, a measure of communicative participation, and the use of effect size benchmarks specific to AOS. Method A single-case experimental design with multiple baselines across behaviors and participants was used to examine acquisition, generalization, and maintenance of treatment effects 8–10 weeks posttreatment. Treatment was distributed 3 days a week, and duration of treatment was specific to each participant (criterion based). Experimental stimuli consisted of target sounds or clusters embedded nonwords and real words, specific to each participants' deficit. Results Findings show improved repetition accuracy for targets in trained nonwords, generalization to targets in untrained nonwords and real words, and maintenance of treatment effects at 10 weeks posttreatment for one participant and more variable outcomes for the other participant. Conclusions Results indicate that a modified version of PMT can promote generalization and maintenance of treatment gains for trained speech targets via a multimodal approach emphasizing repeated exposure and practice. While these results are promising, the frequent co-occurrence of AOS and aphasia warrants a treatment that addresses both motor planning and linguistic deficits. Thus, the application of traditional PMT with participant-specific modifications for AOS embedded into the treatment program may be a more effective approach. Future work will continue to examine and maximize improvements in motor planning, while also treating anomia in aphasia.

Confirmatory Factor Analysis of the Long and Short Forms of the Worry Domains Questionnaire

2009 ◽  
Vol 25 (4) ◽  
pp. 239-243
Author(s):  
Roberto Nuevo ◽  
Andrés Losada ◽  
María Márquez-González ◽  
Cecilia Peñacoba
Keyword(s):  
Factor Analysis ◽  
Confirmatory Factor Analysis ◽  
Factor Structure ◽  
Goodness Of Fit ◽  
Factorial Validity ◽  
Fit Indices ◽  
Short Forms ◽  
Confirmatory Factor ◽  
Positive Correlations ◽  
Future Work

The Worry Domains Questionnaire was proposed as a measure of both pathological and nonpathological worry, and assesses the frequency of worrying about five different domains: relationships, lack of confidence, aimless future, work, and financial. The present study analyzed the factor structure of the long and short forms of the WDQ (WDQ and WDQ-SF, respectively) through confirmatory factor analysis in a sample of 262 students (M age = 21.8; SD = 2.6; 86.3% females). While the goodness-of-fit indices did not provide support for the WDQ, good fit indices were found for the WDQ-SF. Furthermore, no source of misspecification was identified, thus, supporting the factorial validity of the WDQ-SF scale. Significant positive correlations between the WDQ-SF and its subscales with worry (PSWQ), anxiety (STAI-T), and depression (BDI) were found. The internal consistency was good for the total scale and for the subscales. This work provides support for the use of the WDQ-SF, and potential uses for research and clinical purposes are discussed.

Psychology in Outerspace

2010 ◽  
Vol 15 (3) ◽  
pp. 220-228 ◽  
Author(s):  
Viren Swami ◽  
Tomas Chamorro-Premuzic ◽  
Manal Shafi
Keyword(s):  
Individual Difference ◽  
Sensation Seeking ◽  
Structural Equation ◽  
Political Orientation ◽  
Equation Modeling ◽  
Big Five Personality ◽  
Social Conformity ◽  
Extraterrestrial Life ◽  
Paranormal Beliefs ◽  
Future Work

Previous work has shown that is important to consider the disjunction between paranormal and nonparanormal beliefs about extraterrestrial life. The current study examined the association between both such beliefs and individual difference and demographic variables. A total of 555 British participants completed the Extraterrestrial Beliefs Scale, as well as measures of their Big Five personality scores, social conformity, sensation seeking, and demographics. Results showed no sex differences in ratings of paranormal and nonparanormal extraterrestrial beliefs, but participants rated nonparanormal beliefs more positively than paranormal beliefs. Results of structural equation modeling showed that individual difference factors (specifically, Openness, Conscientiousness, and social conformity) explained 21% of the variance in extraterrestrial beliefs, whereas demographic factors (specifically, education level, political orientation, and religiosity) explained 16% of the variance. Limitations and directions for future work are considered.

Arthrodesis of the Distal Two Tarsal Joints in the Horse Using Perforated Stainless Steel Cylinders and Cancellous Bone Graft

1991 ◽  
Vol 4 (01) ◽  
pp. 21-27 ◽  
Author(s):  
R. M. Archer ◽  
R. K. Schneider
Keyword(s):  
Stainless Steel ◽  
Bone Graft ◽  
Cancellous Bone ◽  
Cancellous Bone Graft ◽  
The Third ◽  
Partial Fusion

SummaryTwo perforated stainless steel cylinders and autogenous cancellous bone were implanted into each of the distal intertarsal and tarsometatarsal joints of seven horses. In two control horses holes were drilled into each joint and autogenous cancellous bone was implanted without stainless steel cylinders. Horses which had cylinders implanted in the distal tarsal joints exhibited less lameness and were more comfortable following surgery than were the control horses. Fracture of the third tarsal, central tarsal, or third metatarsal occurred in five of the seven horses implanted with stainless steel cylinders within 45 days of surgery. Two implanted horses and two control horses were observed for five months after surgery. Partial fusion of the distal tarsal joints occurred in all four horses. Control horses were more lame than the implanted horses and developed a large bony exostosis over the medial distal tarsus.

Gertrude Stein's Transmasculinity

2018 ◽  
Author(s):  
Chris Coffman
Keyword(s):  
Twentieth Century ◽  
Ernest Hemingway ◽  
Pablo Picasso ◽  
False Consciousness ◽  
Mass Consumption ◽  
Museum Exhibits ◽  
Carl Van Vechten ◽  
The Media ◽  
Future Work ◽  
Opening Up

By reading written and visual artefacts of Gertrude Stein’s life, Gertrude Stein’s Transmasculinity reframes earlier scholarship to argue that her gender was transmasculine and that her masculinity was positive rather than a self-hating form of false consciousness. This book considers ways Stein’s masculinity was formed through her relationship with her feminine partner, Alice B. Toklas, and her masculine homosocial bonds with other modernists in her network. This broadens out Eve Kosofsky Sedgwick’s account of “male homosocial bonding” to include all masculine persons, opening up the possibility of examining Stein’s relationship to Toklas; masculine women such as Jane Heap; and men such as Pablo Picasso, Ernest Hemingway, and Carl Van Vechten. The Introduction and first four chapters focus on surfacings of Stein’s masculinity within the visual and the textual: in others’ paintings and photographs of her person; her hermetic writings from the first three decades of the twentieth century; and her self-packaging for mass consumption in The Autobiography of Alice B. Toklas (1933). Whereas the chapter on The Autobiography underscores Toklas’s role in the formation of Stein’s masculinity and success as a modernist, the final three register the vicissitudes of the homosocial bonds at play in her friendships with Picasso, Hemingway, and Van Vechten. The Coda, which cross-reads Stein’s Everybody’s Autobiography (1937) with the media attention two museum exhibits about her attracted between 2011 and 2012, points to possibilities for future work on the implications of her masculine homosocial bonds with Vichy collaborator Bernard Fäy.

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