Sample records for procrustes analysis gpa
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Peters, James R; Campbell, Robert M; Balasubramanian, Sriram
2017-10-03
Generalized Procrustes Analysis (GPA) is a superimposition method used to generate size-invariant distributions of homologous landmark points. Several studies have used GPA to assess the three-dimensional (3D) shapes of or to evaluate sex-related differences in the human brain, skull, rib cage, pelvis and lower limbs. Previous studies of the pediatric thoracic vertebrae suggest that they may undergo changes in shape asa result of normative growth. This study uses GPA and second order polynomial equations to model growth and age- and sex-related changes in shape of the pediatric thoracic spine. We present a thorough analysis of the normative 3D shape, size, and orientation of the pediatric thoracic spine and vertebrae as well as equations which can be used to generate models of the thoracic spine and vertebrae for any age between 1 and 19years. Such models could be used to create more accurate 3D reconstructions of the thoracic spine, generate improved age-specific geometries for finite element models (FEMs) and used to assist clinicians with patient-specific planning and surgical interventions for spine deformity. Copyright © 2017 Elsevier Ltd. All rights reserved.
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NASA Astrophysics Data System (ADS)
Fox, Neil I.; Micheas, Athanasios C.; Peng, Yuqiang
2016-07-01
This paper introduces the use of Bayesian full Procrustes shape analysis in object-oriented meteorological applications. In particular, the Procrustes methodology is used to generate mean forecast precipitation fields from a set of ensemble forecasts. This approach has advantages over other ensemble averaging techniques in that it can produce a forecast that retains the morphological features of the precipitation structures and present the range of forecast outcomes represented by the ensemble. The production of the ensemble mean avoids the problems of smoothing that result from simple pixel or cell averaging, while producing credible sets that retain information on ensemble spread. Also in this paper, the full Bayesian Procrustes scheme is used as an object verification tool for precipitation forecasts. This is an extension of a previously presented Procrustes shape analysis based verification approach into a full Bayesian format designed to handle the verification of precipitation forecasts that match objects from an ensemble of forecast fields to a single truth image. The methodology is tested on radar reflectivity nowcasts produced in the Warning Decision Support System - Integrated Information (WDSS-II) by varying parameters in the K-means cluster tracking scheme.
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Procrustes Matching by Congruence Coefficients
ERIC Educational Resources Information Center
Korth, Bruce; Tucker, L. R.
1976-01-01
Matching by Procrustes methods involves the transformation of one matrix to match with another. A special least squares criterion, the congruence coefficient, has advantages as a criterion for some factor analytic interpretations. A Procrustes method maximizing the congruence coefficient is given. (Author/JKS)
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ERIC Educational Resources Information Center
Adachi, Kohei
2009-01-01
In component analysis solutions, post-multiplying a component score matrix by a nonsingular matrix can be compensated by applying its inverse to the corresponding loading matrix. To eliminate this indeterminacy on nonsingular transformation, we propose Joint Procrustes Analysis (JPA) in which component score and loading matrices are simultaneously…
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Human action classification using procrustes shape theory
NASA Astrophysics Data System (ADS)
Cho, Wanhyun; Kim, Sangkyoon; Park, Soonyoung; Lee, Myungeun
2015-02-01
In this paper, we propose new method that can classify a human action using Procrustes shape theory. First, we extract a pre-shape configuration vector of landmarks from each frame of an image sequence representing an arbitrary human action, and then we have derived the Procrustes fit vector for pre-shape configuration vector. Second, we extract a set of pre-shape vectors from tanning sample stored at database, and we compute a Procrustes mean shape vector for these preshape vectors. Third, we extract a sequence of the pre-shape vectors from input video, and we project this sequence of pre-shape vectors on the tangent space with respect to the pole taking as a sequence of mean shape vectors corresponding with a target video. And we calculate the Procrustes distance between two sequences of the projection pre-shape vectors on the tangent space and the mean shape vectors. Finally, we classify the input video into the human action class with minimum Procrustes distance. We assess a performance of the proposed method using one public dataset, namely Weizmann human action dataset. Experimental results reveal that the proposed method performs very good on this dataset.
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Three-dimensional Procrustes analysis of modern human craniofacial form.
Badawi-Fayad, Jackie; Cabanis, Emmanuel-Alain
2007-03-01
The objective of this study was to analyze modern human craniofacial form using 3D Procrustes superimposition in order to establish a reference model and validate it on computed tomography (CT). The sample consists of 136 specimens from five modern human regional groups. Thirty-three craniofacial landmark coordinates have been recorded using a Microscribe and calculated on CT scans for five crania from the sample. Procrustes superimposition has been performed to calculate the mean shape, and a discriminant analysis has also been carried out to estimate the variability of shape. The results show that the repeatability of measurements made on CT and on Microscribe is excellent (R = 0.99). There is no major distinctiveness in the craniofacial shape; however, discriminant function 1 separates out the European crania from the others, especially African and American. It includes the width and the length of the face, the flatness of the upper face, the prognathism of the maxilla, as well as the length and the inclination of the palate. The width of the maxilla and the palate do not show a great variability. This may be the common invariant feature responsible for the alignment of the teeth in all specimens. It may correspond to functional patterns related to masticatory constraints manifested by the important interproximal and occlusal dental wear in all specimens. This study confirms the high accuracy of measurements made on CT scan and the importance of geometric morphometrics, which provides an accurate characterization of the overall craniofacial shape and its variation within the entire population.
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Passos, Pedro; Campos, Tania; Diniz, Ana
2017-01-01
Game consoles allow subjects to perform movements which are visually similar to the movements performed in 'real' world scenarios. Beyond entertainment, virtual reality devices are being used in several domains: sports performance; motor rehabilitation; training of risk professions. This article presents the Procrustes method to measure the degree of dissimilarity between movements performed in 'real' and 'virtual' scenarios. For this purpose, the 501 darts game and a video darts game played on a console were used. The participants' arm throwing movements were video recorded and digitized. The matrices of x and y coordinates of the movements of the wrist, elbow, and shoulder in both performance scenarios were subjected to the Procrustes method. The wrist displays the most extreme dissimilarity values (higher than elbow and shoulder). Results also revealed smaller dissimilarity values for movements performed under the same conditions (e.g., real-real) and larger dissimilarity values between movements performed in different scenarios.
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Passos, Pedro; Campos, Tania; Diniz, Ana
2017-01-01
Game consoles allow subjects to perform movements which are visually similar to the movements performed in ‘real’ world scenarios. Beyond entertainment, virtual reality devices are being used in several domains: sports performance; motor rehabilitation; training of risk professions. This article presents the Procrustes method to measure the degree of dissimilarity between movements performed in ‘real’ and ‘virtual’ scenarios. For this purpose, the 501 darts game and a video darts game played on a console were used. The participants’ arm throwing movements were video recorded and digitized. The matrices of x and y coordinates of the movements of the wrist, elbow, and shoulder in both performance scenarios were subjected to the Procrustes method. The wrist displays the most extreme dissimilarity values (higher than elbow and shoulder). Results also revealed smaller dissimilarity values for movements performed under the same conditions (e.g., real–real) and larger dissimilarity values between movements performed in different scenarios. PMID:28503159
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Orthogonal Procrustes Analysis for Dictionary Learning in Sparse Linear Representation
Grossi, Giuliano; Lin, Jianyi
2017-01-01
In the sparse representation model, the design of overcomplete dictionaries plays a key role for the effectiveness and applicability in different domains. Recent research has produced several dictionary learning approaches, being proven that dictionaries learnt by data examples significantly outperform structured ones, e.g. wavelet transforms. In this context, learning consists in adapting the dictionary atoms to a set of training signals in order to promote a sparse representation that minimizes the reconstruction error. Finding the best fitting dictionary remains a very difficult task, leaving the question still open. A well-established heuristic method for tackling this problem is an iterative alternating scheme, adopted for instance in the well-known K-SVD algorithm. Essentially, it consists in repeating two stages; the former promotes sparse coding of the training set and the latter adapts the dictionary to reduce the error. In this paper we present R-SVD, a new method that, while maintaining the alternating scheme, adopts the Orthogonal Procrustes analysis to update the dictionary atoms suitably arranged into groups. Comparative experiments on synthetic data prove the effectiveness of R-SVD with respect to well known dictionary learning algorithms such as K-SVD, ILS-DLA and the online method OSDL. Moreover, experiments on natural data such as ECG compression, EEG sparse representation, and image modeling confirm R-SVD’s robustness and wide applicability. PMID:28103283
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Orthogonal Procrustes Analysis for Dictionary Learning in Sparse Linear Representation.
Grossi, Giuliano; Lanzarotti, Raffaella; Lin, Jianyi
2017-01-01
In the sparse representation model, the design of overcomplete dictionaries plays a key role for the effectiveness and applicability in different domains. Recent research has produced several dictionary learning approaches, being proven that dictionaries learnt by data examples significantly outperform structured ones, e.g. wavelet transforms. In this context, learning consists in adapting the dictionary atoms to a set of training signals in order to promote a sparse representation that minimizes the reconstruction error. Finding the best fitting dictionary remains a very difficult task, leaving the question still open. A well-established heuristic method for tackling this problem is an iterative alternating scheme, adopted for instance in the well-known K-SVD algorithm. Essentially, it consists in repeating two stages; the former promotes sparse coding of the training set and the latter adapts the dictionary to reduce the error. In this paper we present R-SVD, a new method that, while maintaining the alternating scheme, adopts the Orthogonal Procrustes analysis to update the dictionary atoms suitably arranged into groups. Comparative experiments on synthetic data prove the effectiveness of R-SVD with respect to well known dictionary learning algorithms such as K-SVD, ILS-DLA and the online method OSDL. Moreover, experiments on natural data such as ECG compression, EEG sparse representation, and image modeling confirm R-SVD's robustness and wide applicability.
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Recovering Wood and McCarthy's ERP-prototypes by means of ERP-specific procrustes-rotation.
Beauducel, André
2018-02-01
The misallocation of treatment-variance on the wrong component has been discussed in the context of temporal principal component analysis of event-related potentials. There is, until now, no rotation-method that can perfectly recover Wood and McCarthy's prototypes without making use of additional information on treatment-effects. In order to close this gap, two new methods: for component rotation were proposed. After Varimax-prerotation, the first method identifies very small slopes of successive loadings. The corresponding loadings are set to zero in a target-matrix for event-related orthogonal partial Procrustes- (EPP-) rotation. The second method generates Gaussian normal distributions around the peaks of the Varimax-loadings and performs orthogonal Procrustes-rotation towards these Gaussian distributions. Oblique versions of this Gaussian event-related Procrustes- (GEP) rotation and of EPP-rotation are based on Promax-rotation. A simulation study revealed that the new orthogonal rotations recover Wood and McCarthy's prototypes and eliminate misallocation of treatment-variance. In an additional simulation study with a more pronounced overlap of the prototypes GEP Promax-rotation reduced the variance misallocation slightly more than EPP Promax-rotation. Comparison with Existing Method(s): Varimax- and conventional Promax-rotations resulted in substantial misallocations of variance in simulation studies when components had temporal overlap. A substantially reduced misallocation of variance occurred with the EPP-, EPP Promax-, GEP-, and GEP Promax-rotations. Misallocation of variance can be minimized by means of the new rotation methods: Making use of information on the temporal order of the loadings may allow for improvements of the rotation of temporal PCA components. Copyright © 2017 Elsevier B.V. All rights reserved.
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Sex determination by three-dimensional geometric morphometrics of the palate and cranial base.
Chovalopoulou, Maria-Eleni; Valakos, Efstratios D; Manolis, Sotiris K
2013-01-01
The purpose of this study is to assess sexual dimorphism in the palate and base of adult crania using three-dimensional geometric morphometric methods. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived during the 20th century in Greece. The three-dimensional co-ordinates of 30 ectocranial landmarks were digitized using a MicroScribe 3DX contact digitizer. Generalized Procrustes Analysis (GPA) was used to obtain size and shape variables for statistical analysis. Three discriminant function analyses were carried out: (1) using PC scores from Procrustes shape space, (2) centroid size alone, and (3) PC scores of GPA residuals which includes InCS for analysis in Procrustes form space. Results indicate that there are shape differences between sexes. In males, the palate is deepest and more elongated; the cranial base is shortened. Sex-specific shape differences for the cross-validated data give better classification results in the cranial base (77.2%) compared with the palate (68.9%). Size alone yielded better results for cranial base (82%) in opposition to palate (63.1%). As anticipated, the classification accuracy improves when both size and shape are combined (90.4% for cranial base, and 74.8% for palate).
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The Impact of Measurement Noise in GPA Diagnostic Analysis of a Gas Turbine Engine
NASA Astrophysics Data System (ADS)
Ntantis, Efstratios L.; Li, Y. G.
2013-12-01
The performance diagnostic analysis of a gas turbine is accomplished by estimating a set of internal engine health parameters from available sensor measurements. No physical measuring instruments however can ever completely eliminate the presence of measurement uncertainties. Sensor measurements are often distorted by noise and bias leading to inaccurate estimation results. This paper explores the impact of measurement noise on Gas Turbine GPA analysis. The analysis is demonstrated with a test case where gas turbine performance simulation and diagnostics code TURBOMATCH is used to build a performance model of a model engine similar to Rolls-Royce Trent 500 turbofan engine, and carry out the diagnostic analysis with the presence of different levels of measurement noise. Conclusively, to improve the reliability of the diagnostic results, a statistical analysis of the data scattering caused by sensor uncertainties is made. The diagnostic tool used to deal with the statistical analysis of measurement noise impact is a model-based method utilizing a non-linear GPA.
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Fernández-Varela, R; Andrade, J M; Muniategui, S; Prada, D; Ramírez-Villalobos, F
2010-04-01
Identifying petroleum-related products released into the environment is a complex and difficult task. To achieve this, polycyclic aromatic hydrocarbons (PAHs) are of outstanding importance nowadays. Despite traditional quantitative fingerprinting uses straightforward univariate statistical analyses to differentiate among oils and to assess their sources, a multivariate strategy based on Procrustes rotation (PR) was applied in this paper. The aim of PR is to select a reduced subset of PAHs still capable of performing a satisfactory identification of petroleum-related hydrocarbons. PR selected two subsets of three (C(2)-naphthalene, C(2)-dibenzothiophene and C(2)-phenanthrene) and five (C(1)-decahidronaphthalene, naphthalene, C(2)-phenanthrene, C(3)-phenanthrene and C(2)-fluoranthene) PAHs for each of the two datasets studied here. The classification abilities of each subset of PAHs were tested using principal components analysis, hierarchical cluster analysis and Kohonen neural networks and it was demonstrated that they unraveled the same patterns as the overall set of PAHs. (c) 2009 Elsevier Ltd. All rights reserved.
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Bayesian comparison of protein structures using partial Procrustes distance.
Ejlali, Nasim; Faghihi, Mohammad Reza; Sadeghi, Mehdi
2017-09-26
An important topic in bioinformatics is the protein structure alignment. Some statistical methods have been proposed for this problem, but most of them align two protein structures based on the global geometric information without considering the effect of neighbourhood in the structures. In this paper, we provide a Bayesian model to align protein structures, by considering the effect of both local and global geometric information of protein structures. Local geometric information is incorporated to the model through the partial Procrustes distance of small substructures. These substructures are composed of β-carbon atoms from the side chains. Parameters are estimated using a Markov chain Monte Carlo (MCMC) approach. We evaluate the performance of our model through some simulation studies. Furthermore, we apply our model to a real dataset and assess the accuracy and convergence rate. Results show that our model is much more efficient than previous approaches.
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NASA Astrophysics Data System (ADS)
Narayana, C.; Greene, R. G.; Ruoff, A. L.
2008-07-01
Raman and x-ray diffraction studies were made on silane in the diamond anvil cell using three different gaskets, stainless steel, tungsten and rhenium. The structure existing between 10 and 27 GPa is well characterized by the monoclinic space group P21c (#14). While the Gibbs free energy of formation of silane is positive at one atmosphere, it is calculated from the equation of state of silane and its reactants that this becomes negative near 4 GPa and remains negative until 13 GPa and then becomes positive again. At about 27 GPa, where quasi-quantum mechanical calculations suggest there should be a transformation from 4-fold to 6-fold (or even higher), the sample turns black. The Raman modes seize to exist beyond 30 GPa after showing softening above 25 GPa. At higher pressures it turns silvery. The gaskets play a different role as will be discussed. The sample brought back from 70 GPa contains amorphous Si (with attached hydrogen) as well as crystalline silicon. The lowest free energy system at high pressure is the decomposed reactants as observed.
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González-Tomás, L; Costell, E
2006-12-01
Consumers' perceptions of the color and texture of 8 commercial vanilla dairy desserts were studied and related to color and rheological measurements. First, the 8 desserts were evaluated by a group of consumers by means of the Free Choice Profile. For both color and texture, a 2-dimensional solution was chosen, with dimension 1 highly related to yellow color intensity in the case of color and to thickness in the case of texture. Second, mechanical spectra, flow behavior, and instrumental color were determined. All the samples showed a time-dependent and shear-thinning flow and a mechanical spectrum typical of a weak gel. Differences were found in the flow index, in the apparent viscosity at 10 s(-1), and in the values of the storage modulus, the loss modulus, the loss angle tangent, and the complex viscosity at 1 Hz, as well as in the color parameters. Finally, sensory and instrumental relationships were investigated by a generalized Procrustes analysis. For both color and texture, a 3-dimensional solution explained a high percentage of the total variance (>80%). In these particular samples, the instrumental color parameters provided more accurate information on consumers' color perceptions than was provided by the rheological parameters of consumers' perceptions of texture.
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Penin, Xavier; Berge, Christine; Baylac, Michel
2002-05-01
Heterochronic studies compare ontogenetic trajectories of an organ in different species: here, the skulls of common chimpanzees and modern humans. A growth trajectory requires three parameters: size, shape, and ontogenetic age. One of the great advantages of the Procrustes method is the precise definition of size and shape for whole organs such as the skull. The estimated ontogenetic age (dental stages) is added to the plot to give a graphical representation to compare growth trajectories. We used the skulls of 41 Homo sapiens and 50 Pan troglodytes at various stages of growth. The Procrustes superimposition of all specimens was completed by statistical procedures (principal component analysis, multivariate regression, and discriminant function) to calculate separately size-related shape changes (allometry common to chimpanzees and humans), and interspecific shape differences (discriminant function). The results confirm the neotenic theory of the human skull (sensu Gould [1977] Ontogeny and Phylogeny, Cambridge: Harvard University Press; Alberch et al. [1979] Paleobiology 5:296-317), but modify it slightly. Human growth is clearly retarded in terms of both the magnitude of changes (size-shape covariation) and shape alone (size-shape dissociation) with respect to the chimpanzees. At the end of growth, the adult skull in humans reaches an allometric shape (size-related shape) which is equivalent to that of juvenile chimpanzees with no permanent teeth, and a size which is equivalent to that of adult chimpanzees. Our results show that human neoteny involves not only shape retardation (paedomorphosis), but also changes in relative growth velocity. Before the eruption of the first molar, human growth is accelerated, and then strongly decelerated, relative to the growth of the chimpanzee as a reference. This entails a complex process, which explains why these species reach the same overall (i.e., brain + face) size in adult stage. The neotenic traits seem to concern
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The shape of the hominoid proximal femur: a geometric morphometric analysis
Harmon, Elizabeth H
2007-01-01
As part of the hip joint, the proximal femur is an integral locomotor component. Although a link between locomotion and the morphology of some aspects of the proximal femur has been identified, inclusive shapes of this element have not been compared among behaviourally heterogeneous hominoids. Previous analyses have partitioned complex proximal femoral morphology into discrete features (e.g. head, neck, greater trochanter) to facilitate conventional linear measurements. In this study, three-dimensional geometric morphometrics are used to examine the shape of the proximal femur in hominoids to determine whether femoral shape co-varies with locomotor category. Fourteen landmarks are recorded on adult femora of Homo, Pan, Gorilla, Pongo and Hylobates. Generalized Procrustes analysis (GPA) is used to adjust for position, orientation and scale among landmark configurations. Principal components analysis is used to collapse and compare variation in residuals from GPA, and thin-plate spline analysis is used to visualize shape change among taxa. The results indicate that knucklewalking African apes are similar to one another in femoral shape, whereas the more suspensory Asian apes diverge from the African ape pattern. The shape of the human and orangutan proximal femur converge, a result that is best explained in terms of the distinct requirements for locomotion in each group. These findings suggest that the shape of the proximal femur is brought about primarily by locomotor behaviour. PMID:17310545
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Laser Interferometry Measurements of Cold-Sprayed Copper Thermite Shocked to 30 GPa
NASA Astrophysics Data System (ADS)
Neel, Christopher; Lacina, David
2015-06-01
Plate impact experiments were conducted on a cold-sprayed Al-CuO thermite at peak stresses varying between 5-30 GPa to determine the Hugoniot and characterize any shock induced energetic reaction. Photon Doppler Velocimetry (PDV) measurements were used to obtain particle velocity histories and shock speed information for both the shock loading and unloading behavior of the material. Low stress experiments (<20GPa) exhibited a linearly increasing shock speed with increasing particle velocity. However, an obvious change in slope (i.e. a ``kink'') is present in the Hugoniot at stresses above ~ 20 GPa which follow a linear increase up to the highest stresses attained in this work. The change in Hugoniot curve suggests a volume-increasing reaction occurs in this shocked Al-CuO thermite near 20 GPa, but an analysis of the measured particle velocity histories does not support this assertion. To better characterize any shock-induced thermite reactions, emission spectroscopy measurements were obtained at stresses above and below 20 GPa.
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Ramp compression of magnesium oxide to 234 GPa
Wang, Jue; Smith, R. F.; Coppari, F.; ...
2014-05-07
Single-crystal magnesium oxide (MgO) samples were ramp compressed to above 200 GPa pressure at the Omega laser facility. Multi-stepped MgO targets were prepared using lithography and wet etching techniques. Free surface velocities of ramp-compressed MgO were measured with a VISAR. The sound velocity and stress-density response were determined using an iterative Lagrangian analysis. The measured equation of state is consistent with expectations from previous shock and static data as well as with a recent X-ray diffraction measurement under ramp loading. The peak elastic stresses observed in our samples had amplitudes of 3-5.5 GPa, decreasing with propagation distance.
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Polsin, D. N.; Fratanduono, D. E.; Rygg, J. R.; ...
2017-10-27
Nanosecond in situ x-ray diffraction and simultaneous velocimetry measurements were used to determine the crystal structure and pressure, respectively, of ramp compressed aluminum at stress states between 111 and 475 GPa. The solid-solid Al phase transformations, fcc-hcp and hcp-bcc, are observed at 216 ± 9 GPa and 321 ± 12 GPa, respectively, with the bcc phase persisting to 475 GPa. Here, this is the first in situ observation of the high-pressure bcc phase of Al. High-pressure texture of the hcp and bcc phases suggests close-packed or nearly close-packed lattice planes remain parallel through both transformations.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Polsin, D. N.; Fratanduono, D. E.; Rygg, J. R.
Nanosecond in situ x-ray diffraction and simultaneous velocimetry measurements were used to determine the crystal structure and pressure, respectively, of ramp compressed aluminum at stress states between 111 and 475 GPa. The solid-solid Al phase transformations, fcc-hcp and hcp-bcc, are observed at 216 ± 9 GPa and 321 ± 12 GPa, respectively, with the bcc phase persisting to 475 GPa. Here, this is the first in situ observation of the high-pressure bcc phase of Al. High-pressure texture of the hcp and bcc phases suggests close-packed or nearly close-packed lattice planes remain parallel through both transformations.
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The influence of MCAT and GPA preadmission academic metrics on interview scores.
Gay, Steven E; Santen, Sally A; Mangrulkar, Rajesh S; Sisson, Thomas H; Ross, Paula T; Zaidi, Nikki L Bibler
2018-03-01
Medical school admissions interviews are used to assess applicants' nonacademic characteristics as advocated by the Association of American Medical Colleges' Advancing Holistic Review Initiative. The objective of this study is to determine whether academic metrics continue to significantly influence interviewers' scores in holistic processes by blinding interviewers to applicants' undergraduate grade point averages (uGPA) and Medical College Admission Test (MCAT). This study examines academic and demographic predictors of interview scores for two applicant cohorts at the University of Michigan Medical School. In 2012, interviewers were provided applicants' uGPA and MCAT scores; in 2013, these academic metrics were withheld from interviewers' files. Hierarchical regression analysis was conducted to examine the influence of academic and demographic variables on overall cohort interview scores. When interviewers were provided uGPA and MCAT scores, academic metrics explained more variation in interview scores (7.9%) than when interviewers were blinded to these metrics (4.1%). Further analysis showed a statistically significant interaction between cohort and uGPA, indicating that the association between uGPA and interview scores was significantly stronger for the 2012 unblinded cohort compared to the 2013 blinded cohort (β = .573, P < .05). By contrast, MCAT scores had no interactive effects on interviewer scores. While MCAT scores accounted for some variation in interview scores for both cohorts, only access to uGPA significantly influenced interviewers' scores when looking at interaction effects. Withholding academic metrics from interviewers' files may promote assessment of nonacademic characteristics independently from academic metrics.
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Meyer, Swanhild U.; Kaiser, Sebastian; Wagner, Carola; Thirion, Christian; Pfaffl, Michael W.
2012-01-01
Background Adequate normalization minimizes the effects of systematic technical variations and is a prerequisite for getting meaningful biological changes. However, there is inconsistency about miRNA normalization performances and recommendations. Thus, we investigated the impact of seven different normalization methods (reference gene index, global geometric mean, quantile, invariant selection, loess, loessM, and generalized procrustes analysis) on intra- and inter-platform performance of two distinct and commonly used miRNA profiling platforms. Methodology/Principal Findings We included data from miRNA profiling analyses derived from a hybridization-based platform (Agilent Technologies) and an RT-qPCR platform (Applied Biosystems). Furthermore, we validated a subset of miRNAs by individual RT-qPCR assays. Our analyses incorporated data from the effect of differentiation and tumor necrosis factor alpha treatment on primary human skeletal muscle cells and a murine skeletal muscle cell line. Distinct normalization methods differed in their impact on (i) standard deviations, (ii) the area under the receiver operating characteristic (ROC) curve, (iii) the similarity of differential expression. Loess, loessM, and quantile analysis were most effective in minimizing standard deviations on the Agilent and TLDA platform. Moreover, loess, loessM, invariant selection and generalized procrustes analysis increased the area under the ROC curve, a measure for the statistical performance of a test. The Jaccard index revealed that inter-platform concordance of differential expression tended to be increased by loess, loessM, quantile, and GPA normalization of AGL and TLDA data as well as RGI normalization of TLDA data. Conclusions/Significance We recommend the application of loess, or loessM, and GPA normalization for miRNA Agilent arrays and qPCR cards as these normalization approaches showed to (i) effectively reduce standard deviations, (ii) increase sensitivity and accuracy of
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Investigating the utility of a GPA institutional adjustment index.
Didier, Thomas; Kreiter, Clarence D; Buri, Russell; Solow, Catherine
2006-05-01
Grading standards vary widely across undergraduate institutions. If, during the medical school admissions process, GPA is considered without reference to the institution attended, it will disadvantage applicants from undergraduate institutions employing rigorous grading standards. A regression-based GPA institutional equating method using historical MCAT and GPA information is described. Classes selected from eight applicant pools demonstrate the impact of the GPA adjustment. The validity of the adjustment is examined by comparing adjusted and unadjusted GPAs' correlation with USMLE and medical college grades. The adjusted GPA demonstrated significantly improved congruence with MCAT estimates of applicant preparedness. The adjustment changed selection decisions for 21% of those admitted. The adjusted GPA enhanced prediction of USMLE and medical school grades only for students from institutions which required large adjustments. Unlike other indices, the adjustment described uses the same metric as GPA and is based only on an institution's history of preparing medical school applicants. The institutional adjustment is consequential in selection, significantly enhances congruence with a standardized measure of academic preparedness and may enhance the validity of the GPA.
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ERIC Educational Resources Information Center
Kadhi, T.; Holley, D.; Palasota, A.; Garrison, P.; Green, T.
2010-01-01
The following analysis was done to investigate the findings of the Correlational Relationship (R) between the Bar Passing Rates and GPAs of the Years 2005-2009. This report of findings was done to see if there are any significant relationships between the three variables (Bar Pass/Fail/Unknown, Overall GPA, and Bar GPA). The following procedures…
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GPA protects the nigrostriatal dopamine system by enhancing mitochondrial function.
Horvath, Tamas L; Erion, Derek M; Elsworth, John D; Roth, Robert H; Shulman, Gerald I; Andrews, Zane B
2011-07-01
Guanidinopropionic acid (GPA) increases AMPK activity, mitochondrial function and biogenesis in muscle and improves physiological function, for example during aging. Mitochondrial dysfunction is a major contributor to the pathogenesis of Parkinson's disease. Here we tested whether GPA prevents neurodegeneration of the nigrostriatal dopamine system in MPTP-treated mice. Mice were fed a diet of 1% GPA or normal chow for 4 weeks and then treated with either MPTP or saline. Indices of nigrostriatal function were examined by HPLC, immunohistochemistry, stereology, electron microscopy and mitochondrial respiration. MPTP intoxication decreased TH neurons in the SNpc of normal chow-fed mice; however GPA-fed mice remarkably exhibited no loss of TH neurons in the SNpc. MPTP caused a decrease in striatal dopamine of both normal chow- and GPA-fed mice, although this effect was significantly attenuated in GPA-fed mice. GPA-fed mice showed increased AMPK activity, mitochondrial respiration and mitochondrial number in nigrostriatal TH neurons, suggesting that the neuroprotective effects of GPA involved AMPK-dependent increases in mitochondrial function and biogenesis. MPTP treatment produced a decrease in mitochondrial number and volume in normal chow-fed mice but not GPA-fed mice. Our results show the neuroprotective properties of GPA in a mouse model of Parkinson's disease are partially mediated by AMPK and mitochondrial function. Mitochondrial dysfunction is a common problem in neurodegeneration and thus GPA may slow disease progression in other models of neurodegeneration. Copyright © 2011 Elsevier Inc. All rights reserved.
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Shock compression response of forsterite above 250 GPa
Sekine, Toshimori; Ozaki, Norimasa; Miyanishi, Kohei; Asaumi, Yuto; Kimura, Tomoaki; Albertazzi, Bruno; Sato, Yuya; Sakawa, Youichi; Sano, Takayoshi; Sugita, Seiji; Matsui, Takafumi; Kodama, Ryosuke
2016-01-01
Forsterite (Mg2SiO4) is one of the major planetary materials, and its behavior under extreme conditions is important to understand the interior structure of large planets, such as super-Earths, and large-scale planetary impact events. Previous shock compression measurements of forsterite indicate that it may melt below 200 GPa, but these measurements did not go beyond 200 GPa. We report the shock response of forsterite above ~250 GPa, obtained using the laser shock wave technique. We simultaneously measured the Hugoniot and temperature of shocked forsterite and interpreted the results to suggest the following: (i) incongruent crystallization of MgO at 271 to 285 GPa, (ii) phase transition of MgO at 285 to 344 GPa, and (iii) remelting above ~470 to 500 GPa. These exothermic and endothermic reactions are seen to occur under extreme conditions of pressure and temperature. They indicate complex structural and chemical changes in the system MgO-SiO2 at extreme pressures and temperatures and will affect the way we understand the interior processes of large rocky planets as well as material transformation by impacts in the formation of planetary systems. PMID:27493993
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Pressure-induced stiffness of Au nanoparticles to 71 GPa under quasi-hydrostatic loading
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hong, Xinguo; Duffy, Thomas S.; Ehm, Lars
2015-11-16
The compressibility of nanocrystalline gold (n-Au, 20 nm) has been studied by x-ray total scattering using high-energy monochromatic x-rays in the diamond anvil cell under quasi-hydrostatic conditions up to 71 GPa. The bulk modulus, K 0, of the n-Au obtained from fitting to a Vinet equation of state is ~196(3) GPa, which is about 17% higher than for the corresponding bulk materials (K 0: 167 GPa). At low pressures (<7 GPa), the compression behavior of n-Au shows little difference from that of bulk Au. With increasing pressure, the compressive behavior of n-Au gradually deviates from the equation of state (EOS)more » of bulk gold. Analysis of the pair distribution function, peak broadening and Rietveld refinement reveals that the microstructure of n-Au is nearly a single-grain/domain at ambient conditions, but undergoes substantial pressure-induced reduction in grain size until 10 GPa. The results indicate that the nature of the internal microstructure in n-Au is associated with the observed EOS difference from bulk Au at high pressure. Full-pattern analysis confirms that significant changes in grain size, stacking faults, grain orientation and texture occur in n-Au at high pressure. We have observed direct experimental evidence of a transition in compressional mechanism for n-Au at ~20 GPa, i.e. from a deformation dominated by nucleation and motion of lattice dislocations (dislocation-mediated) to a prominent grain boundary mediated response to external pressure. In conclusion, the internal microstructure inside the nanoparticle (nanocrystallinity) plays a critical role for the macro-mechanical properties of nano-Au.« less
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Pressure-induced stiffness of Au nanoparticles to 71 GPa under quasi-hydrostatic loading.
Hong, Xinguo; Duffy, Thomas S; Ehm, Lars; Weidner, Donald J
2015-12-09
The compressibility of nanocrystalline gold (n-Au, 20 nm) has been studied by x-ray total scattering using high-energy monochromatic x-rays in the diamond anvil cell under quasi-hydrostatic conditions up to 71 GPa. The bulk modulus, K0, of the n-Au obtained from fitting to a Vinet equation of state is ~196(3) GPa, which is about 17% higher than for the corresponding bulk materials (K0: 167 GPa). At low pressures (<7 GPa), the compression behavior of n-Au shows little difference from that of bulk Au. With increasing pressure, the compressive behavior of n-Au gradually deviates from the equation of state (EOS) of bulk gold. Analysis of the pair distribution function, peak broadening and Rietveld refinement reveals that the microstructure of n-Au is nearly a single-grain/domain at ambient conditions, but undergoes substantial pressure-induced reduction in grain size until 10 GPa. The results indicate that the nature of the internal microstructure in n-Au is associated with the observed EOS difference from bulk Au at high pressure. Full-pattern analysis confirms that significant changes in grain size, stacking faults, grain orientation and texture occur in n-Au at high pressure. We have observed direct experimental evidence of a transition in compressional mechanism for n-Au at ~20 GPa, i.e. from a deformation dominated by nucleation and motion of lattice dislocations (dislocation-mediated) to a prominent grain boundary mediated response to external pressure. The internal microstructure inside the nanoparticle (nanocrystallinity) plays a critical role for the macro-mechanical properties of nano-Au.
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Chung, Dongjun; Kim, Hang J; Zhao, Hongyu
2017-02-01
Genome-wide association studies (GWAS) have identified tens of thousands of genetic variants associated with hundreds of phenotypes and diseases, which have provided clinical and medical benefits to patients with novel biomarkers and therapeutic targets. However, identification of risk variants associated with complex diseases remains challenging as they are often affected by many genetic variants with small or moderate effects. There has been accumulating evidence suggesting that different complex traits share common risk basis, namely pleiotropy. Recently, several statistical methods have been developed to improve statistical power to identify risk variants for complex traits through a joint analysis of multiple GWAS datasets by leveraging pleiotropy. While these methods were shown to improve statistical power for association mapping compared to separate analyses, they are still limited in the number of phenotypes that can be integrated. In order to address this challenge, in this paper, we propose a novel statistical framework, graph-GPA, to integrate a large number of GWAS datasets for multiple phenotypes using a hidden Markov random field approach. Application of graph-GPA to a joint analysis of GWAS datasets for 12 phenotypes shows that graph-GPA improves statistical power to identify risk variants compared to statistical methods based on smaller number of GWAS datasets. In addition, graph-GPA also promotes better understanding of genetic mechanisms shared among phenotypes, which can potentially be useful for the development of improved diagnosis and therapeutics. The R implementation of graph-GPA is currently available at https://dongjunchung.github.io/GGPA/.
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A Raman Spectroscopic Study of Kernite to 25 GPa
NASA Astrophysics Data System (ADS)
Silva, M. E.; O'Bannon, E. F., III; Williams, Q. C.
2015-12-01
A Raman spectroscopic study of kernite to 25 GPaMarcus Silva, Earl O'Bannon III, and Quentin Williams Department of Earth & Planetary Sciences, University of California Santa Cruz The Raman spectrum of kernite (Na2B4O6(OH)2·3(H2O)) has been characterized up to ~25 GPa in order to explore pressure-induced changes in a structurally novel mineral that contains mixed coordination borate groups (three- and four-fold), and both hydroxyl units and water. During compression, all of the ~30 modes monitored shift positively and monotonically until ~2.2 GPa where a few low frequency modes disappear and tetrahedral borate modes merge. The low frequency modes that disappear at ~2.2 GPa are likely associated with Na vibrations, and their disappearance suggests that dramatic changes occur in the Na sites at ~2.2 GPa. The merging of the boron bending and stretching modes at ~2.2 GPa suggests that the local symmetry of the BO4 tetrahedra changes at this pressure, and likely becomes more symmetric. The remaining modes shift positively up to ~7.4 GPa where a second notable change occurs. All but 5 modes (with initial frequencies of 150, 166, 289, 307, and 525 cm-1) disappear at ~7.4 GPa. This indicates that a second phase transition has occurred which affects both the BO3H and BO4 groups: based on the loss of modes, this transition may be associated with disordering of the crystal. These 5 modes persist and shift monotonically up to ~25 GPa. On decompression, the 5 modes shift smoothly down to ~2.0 GPa where a few new modes appear in the spectrum. When fully decompressed to room pressure, the Raman spectrum of the recovered sample is significantly different from the ambient spectrum of the initial sample. Thus, our results are suggest a phase transition occurring at 2.2 GPa with changes in the Na and tetrahedral boron sites, followed by an additional transition at 7.4 GPa that may involve disordering of the crystal. In the latter transition, at least the BO3H groups appear to be
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Sperduto, Paul W.; Shanley, Ryan; Luo, Xianghua; Andrews, David; Werner-Wasik, Maria; Valicenti, Richard; Bahary, Jean-Paul; Souhami, Luis; Won, Minhee; Mehta, Minesh
2015-01-01
Purpose Radiation Therapy Oncology Group (RTOG) 9508 showed a survival advantage for patients with 1 but not 2 or 3 brain metastasis (BM) treated with whole-brain radiation therapy (WBRT) and stereotactic radiosurgery (SRS) versus WBRT alone. An improved prognostic index, the graded prognostic assessment (GPA) has been developed. Our hypothesis was that if the data from RTOG 9508 were poststratified by the GPA, the conclusions may vary. Methods and Materials In this analysis, 252 of the 331 patients were evaluable by GPA. Of those, 211 had lung cancer. Breast cancer patients were excluded because the components of the breast GPA are not in the RTOG database. Multiple Cox regression was used to compare survival between treatment groups, adjusting for GPA. Treatment comparisons within subgroups were performed with the log-rank test. A free online tool (brainmetgpa.com) simplified GPA use. Results The fundamental conclusions of the primary analysis were confirmed in that there was no survival benefit overall for patients with 1 to 3 metastases; however, there was a benefit for the subset of patients with GPA 3.5 to 4.0 (median survival time [MST] for WBRT + SRS vs WBRT alone was 21.0 versus 10.3 months, P = .05) regardless of the number of metastases. Among patients with GPA 3.5 to 4.0 treated with WBRT and SRS, the MST for patients with 1 versus 2 to 3 metastases was 21 and 14.1 months, respectively. Conclusions This secondary analysis of predominantly lung cancer patients, consistent with the original analysis, shows no survival advantage for the group overall when treated with WBRT and SRS; however, in patients with high GPA (3.5-4), there is a survival advantage regardless of whether they have 1, 2, or 3 BM. This benefit did not extend to patients with lower GPA. Prospective validation of this survival benefit for patients with multiple BM and high GPA when treated with WBRT and SRS is warranted. PMID:25304947
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Sperduto, Paul W; Shanley, Ryan; Luo, Xianghua; Andrews, David; Werner-Wasik, Maria; Valicenti, Richard; Bahary, Jean-Paul; Souhami, Luis; Won, Minhee; Mehta, Minesh
2014-11-01
Radiation Therapy Oncology Group (RTOG) 9508 showed a survival advantage for patients with 1 but not 2 or 3 brain metastasis (BM) treated with whole-brain radiation therapy (WBRT) and stereotactic radiosurgery (SRS) versus WBRT alone. An improved prognostic index, the graded prognostic assessment (GPA) has been developed. Our hypothesis was that if the data from RTOG 9508 were poststratified by the GPA, the conclusions may vary. In this analysis, 252 of the 331 patients were evaluable by GPA. Of those, 211 had lung cancer. Breast cancer patients were excluded because the components of the breast GPA are not in the RTOG database. Multiple Cox regression was used to compare survival between treatment groups, adjusting for GPA. Treatment comparisons within subgroups were performed with the log-rank test. A free online tool (brainmetgpa.com) simplified GPA use. The fundamental conclusions of the primary analysis were confirmed in that there was no survival benefit overall for patients with 1 to 3 metastases; however, there was a benefit for the subset of patients with GPA 3.5 to 4.0 (median survival time [MST] for WBRT + SRS vs WBRT alone was 21.0 versus 10.3 months, P=.05) regardless of the number of metastases. Among patients with GPA 3.5 to 4.0 treated with WBRT and SRS, the MST for patients with 1 versus 2 to 3 metastases was 21 and 14.1 months, respectively. This secondary analysis of predominantly lung cancer patients, consistent with the original analysis, shows no survival advantage for the group overall when treated with WBRT and SRS; however, in patients with high GPA (3.5-4), there is a survival advantage regardless of whether they have 1, 2, or 3 BM. This benefit did not extend to patients with lower GPA. Prospective validation of this survival benefit for patients with multiple BM and high GPA when treated with WBRT and SRS is warranted. Copyright © 2014 Elsevier Inc. All rights reserved.
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Strength and texture of sodium chloride to 56 GPa
NASA Astrophysics Data System (ADS)
Mi, Z.; Shieh, S. R.; Kavner, A.; Kiefer, B.; Wenk, H.-R.; Duffy, T. S.
2018-04-01
The strength and texture of sodium chloride in the B1 (rocksalt) and B2 (cesium chloride) phases were investigated in a diamond anvil cell using synchrotron X-ray diffraction in a radial geometry to 56 GPa. The measured differential stresses within the Reuss limit are in the range of 0.2 GPa for the B1 phase at pressure of 24 GPa and 1.6 GPa for the B2 phase at pressure of 56 GPa. A strength weakening is observed near the B1-B2 phase transition at about 30 GPa. The low strength of NaCl in the B1 phase confirms that it is an effective pressure-transmitting medium for high-pressure experiments to ˜30 GPa. The B2 phase can be also used as a pressure-transmitting medium although it exhibits a steeper increase in strength with pressure than the B1 phase. Deformation induces weak lattice preferred orientation in NaCl, showing a (100) texture in the B1 phase and a (110) texture in the B2 phase. The observed textures were evaluated by viscoplastic self-consistent model and our results suggest {110}⟨ 1 1 ¯ 0 ⟩ as the slip system for the B1 phase and {112} ⟨1 1 ¯ 0 ⟩ for the B2 phase.
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Convenient optical pressure gauge for multimegabar pressures calibrated to 300 GPa
NASA Astrophysics Data System (ADS)
Sun, Liling; Ruoff, Arthur L.; Stupian, Gary
2005-01-01
The accurate measurement of pressure by a straightforward and inexpensive optical procedure has been needed in the multimegabar region since static pressures over 216GPa, 361GPa, 420GPa and 560GPa were obtained in the diamond anvil cell. Here, a simple optical pressure gauge based on the Raman shift of the diamond at the center of a diamond tip at the diamond-sample interface is calibrated against a primary gauge (Pt isotherm at 300K from shock data) to 300GPa, thus enabling researchers who do not have a synchrotron to conveniently measure pressure with an optical scale from 50to300GPa.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Sperduto, Paul W., E-mail: psperduto@mropa.com; Shanley, Ryan; Luo, Xianghua
2014-11-01
Purpose: Radiation Therapy Oncology Group (RTOG) 9508 showed a survival advantage for patients with 1 but not 2 or 3 brain metastasis (BM) treated with whole-brain radiation therapy (WBRT) and stereotactic radiosurgery (SRS) versus WBRT alone. An improved prognostic index, the graded prognostic assessment (GPA) has been developed. Our hypothesis was that if the data from RTOG 9508 were poststratified by the GPA, the conclusions may vary. Methods and Materials: In this analysis, 252 of the 331 patients were evaluable by GPA. Of those, 211 had lung cancer. Breast cancer patients were excluded because the components of the breast GPAmore » are not in the RTOG database. Multiple Cox regression was used to compare survival between treatment groups, adjusting for GPA. Treatment comparisons within subgroups were performed with the log-rank test. A free online tool ( (brainmetgpa.com)) simplified GPA use. Results: The fundamental conclusions of the primary analysis were confirmed in that there was no survival benefit overall for patients with 1 to 3 metastases; however, there was a benefit for the subset of patients with GPA 3.5 to 4.0 (median survival time [MST] for WBRT + SRS vs WBRT alone was 21.0 versus 10.3 months, P=.05) regardless of the number of metastases. Among patients with GPA 3.5 to 4.0 treated with WBRT and SRS, the MST for patients with 1 versus 2 to 3 metastases was 21 and 14.1 months, respectively. Conclusions: This secondary analysis of predominantly lung cancer patients, consistent with the original analysis, shows no survival advantage for the group overall when treated with WBRT and SRS; however, in patients with high GPA (3.5-4), there is a survival advantage regardless of whether they have 1, 2, or 3 BM. This benefit did not extend to patients with lower GPA. Prospective validation of this survival benefit for patients with multiple BM and high GPA when treated with WBRT and SRS is warranted.« less
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Structural phase transitions in GaAs to 108 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Weir, S.T.; Vohra, Y.K.; Vanderborgh, C.A.
1989-01-15
The III-V compound GaAs was studied using energy-dispersive x-ray diffraction with a synchro- tron source up to a pressure of 108 GPa. When the pressure was increased to 16.6 GPa, the GaAs sample transformed from the zinc-blende structure to an orthorhombic structure (GaAs(II)), space group Pmm2, consisting of a primitive orthorhombic lattice with a basis of (0,0,0) and (0,(1/2,..cap alpha..), where ..cap alpha.. = 0.35. Upon a further increase of pressure to 24 +- 1 GPa, GaAs(II) transformed to another orthorhombic structure (GaAs(III)), space group Imm2, consisting of a body-centered orthorhombic lattice with a basis of (0,0,0) and (0, (1/2,..delta..),more » where ..delta.. is 0.425 at 28.1 GPa. With increasing pressure, ..delta.. approached (1/2 and the GaAs(III) structure gradually assumed the symmetry of the simple hexagonal structure. The transition to the simple hexagonal structure (GaAs(IV)) was completed in the vicinity of 60--80 GPa. The structure remains simple hexagonal up to at least 108 GPa, the highest pressure reached in this study.« less
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Strength and texture of Pt compressed to 63 GPa
NASA Astrophysics Data System (ADS)
Dorfman, Susannah M.; Shieh, Sean R.; Duffy, Thomas S.
2015-02-01
Angle- and energy-dispersive X-ray diffraction experiments in a radial geometry were performed in the diamond anvil cell on polycrystalline platinum samples at pressures up to 63 GPa. Observed yield strength and texture depend on grain size. For samples with 70-300-nm particle size, the yield strength is 5-6 GPa at ˜60 GPa. Coarse-grained (˜2-μm particles) Pt has a much lower yield strength of 1-1.5 GPa at ˜60 GPa. Face-centered cubic metals Pt and Au have lower strength to shear modulus ratio than body-centered cubic or hexagonal close-packed metals. While a 300-nm particle sample exhibits the <110> texture expected of face-centered-cubic metals under compression, smaller and larger particles show a weak mixed <110> and <100> texture under compression. Differences in texture development may also occur due to deviations from uniaxial stress under compression in the diamond anvil cell.
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Nilson, Sarah E; Assmann, Sarah M
2010-04-01
Land plants must balance CO2 assimilation with transpiration in order to minimize drought stress and maximize their reproductive success. The ratio of assimilation to transpiration is called transpiration efficiency (TE). TE is under genetic control, although only one specific gene, ERECTA, has been shown to regulate TE. We have found that the alpha-subunit of the heterotrimeric G protein in Arabidopsis (Arabidopsis thaliana), GPA1, is a regulator of TE. gpa1 mutants, despite having guard cells that are hyposensitive to abscisic acid-induced inhibition of stomatal opening, have increased TE under ample water and drought stress conditions and when treated with exogenous abscisic acid. Leaf-level gas-exchange analysis shows that gpa1 mutants have wild-type assimilation versus internal CO2 concentration responses but exhibit reduced stomatal conductance compared with ecotype Columbia at ambient and below-ambient internal CO2 concentrations. The increased TE and reduced whole leaf stomatal conductance of gpa1 can be primarily attributed to stomatal density, which is reduced in gpa1 mutants. GPA1 regulates stomatal density via the control of epidermal cell size and stomata formation. GPA1 promoter::beta-glucuronidase lines indicate that the GPA1 promoter is active in the stomatal cell lineage, further supporting a function for GPA1 in stomatal development in true leaves.
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Jin, Xiaofen; Wang, Rui-Sheng; Zhu, Mengmeng; Jeon, Byeong Wook; Albert, Reka; Chen, Sixue; Assmann, Sarah M.
2013-01-01
Individual metabolites have been implicated in abscisic acid (ABA) signaling in guard cells, but a metabolite profile of this specialized cell type is lacking. We used liquid chromatography–multiple reaction monitoring mass spectrometry for targeted analysis of 85 signaling-related metabolites in Arabidopsis thaliana guard cell protoplasts over a time course of ABA treatment. The analysis utilized ∼350 million guard cell protoplasts from ∼30,000 plants of the Arabidopsis Columbia accession (Col) wild type and the heterotrimeric G-protein α subunit mutant, gpa1, which has ABA-hyposensitive stomata. These metabolomes revealed coordinated regulation of signaling metabolites in unrelated biochemical pathways. Metabolites clustered into different temporal modules in Col versus gpa1, with fewer metabolites showing ABA-altered profiles in gpa1. Ca2+-mobilizing agents sphingosine-1-phosphate and cyclic adenosine diphosphate ribose exhibited weaker ABA-stimulated increases in gpa1. Hormone metabolites were responsive to ABA, with generally greater responsiveness in Col than in gpa1. Most hormones also showed different ABA responses in guard cell versus mesophyll cell metabolomes. These findings suggest that ABA functions upstream to regulate other hormones, and are also consistent with G proteins modulating multiple hormonal signaling pathways. In particular, indole-3-acetic acid levels declined after ABA treatment in Col but not gpa1 guard cells. Consistent with this observation, the auxin antagonist α-(phenyl ethyl-2-one)-indole-3-acetic acid enhanced ABA-regulated stomatal movement and restored partial ABA sensitivity to gpa1. PMID:24368793
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Static strength of molybdenum to 92 GPa under radial X-ray diffraction
NASA Astrophysics Data System (ADS)
Xiong, L.; Tu, P.; Li, B.; Wu, S. Y.; Hao, J. B.; Bai, L. G.; Li, X. D.; Liu, J.
2018-06-01
The high-pressure strength of molybdenum (Mo) to 92 GPa has been studied by radial X-ray diffraction (RXRD) technique. The ratio of t/G is found to decrease above ˜24 GPa, showing the yield of Mo which is caused by plastic deformation at this pressure. Combined with high-pressure shear modulus, it was found that the differential stress corresponding to the yield of Mo at 24 GPa due to plastic deformation is 1.73 GPa. The second increase of t values occurs after ˜66 GPa, suggesting the strength of Mo with a differential stress of ˜1.93 GPa. In addition, the maximum difference stress of molybdenum at 87 GPa is 3.01 GPa.
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X-Ray Diffraction Study of Elemental Erbium to 65 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pravica, M.G.; Lipinska-Kalita, K.; Quine, Z.
2006-02-02
We have investigated phase transitions in elemental erbium in a diamond anvil cell up to 65 GPa using x-ray powder diffraction methods. We present preliminary evidence of a series of phase transitions that appear to follow the expected hcp {yields} Sm-type {yields} dhcp {yields} distorted fcc sequence. In particular, we believe that we have evidence for the predicted dhcp {yields} distorted fcc transition between 43 GPa and 65 GPa.
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Investigating the Utility of a GPA Institutional Adjustment Index
ERIC Educational Resources Information Center
Didier, Thomas; Kreiter, Clarence D.; Buri, Russell; Solow, Catherine
2006-01-01
Background: Grading standards vary widely across undergraduate institutions. If, during the medical school admissions process, GPA is considered without reference to the institution attended, it will disadvantage applicants from undergraduate institutions employing rigorous grading standards. Method: A regression-based GPA institutional equating…
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High-pressure polymorphism of Pb F 2 to 75 GPa
Stan, Camelia V.; Dutta, Rajkrishna; White, Claire E.; ...
2016-07-06
Lead fluoride, PbF 2, was investigated experimentally in the laser-heated diamond anvil cell by x-ray diffraction to pressures of 75 GPa at room temperature and to 64.5 GPa and 2430 K, as well as through first-principles density functional theory calculations up to 70 GPa. During room temperature compression, no discontinuous changes in the x-ray diffraction pattern or volume were observed, but the lattice parameters displayed highly anomalous trends between 10-22 GPa with enhanced compressibility along the a direction and reduced or even negative compressibility along b and c. Theoretical calculations of valence electron densities at 22 GPa showed that α-PbFmore » 2 underwent a pressure-induced isosymmetric phase transition to a postcotunnite Co 2Si structure and also revealed the detailed atomic rearrangements associated with the development of an extra Pb-F bond in the high-pressure phase. Our x-ray results and theoretical calculations are consistent with an isosymmetric phase transition smoothly occurring over 10-22 GPa rather than abruptly as previously suggested. The characteristic values for the cell constants a/c and (a+c)/b, which are used to distinguish among cotunnite-, Co 2Si-, and Ni 2In-type phases, require modification based on our results. An equation of state fit yields a bulk modulus, K 0, of 72(3) GPa for the cotunnite-type, and an ambient-pressure volume, V 0, of 182(2)Å 3, and K 0=81(4)GPa for the Co 2Si-type phase when fixing the pressure derivative of the bulk modulus, K 0'=4. Upon heating above 1200 K at pressures at or above 25.9 GPa, PbF 2 partially transformed to the hexagonal Ni 2In-type phase but wholly or partially reverted back to Co 2Si-type phase upon temperature quench. From 43-65 GPa, nearly complete transformation to the Ni 2In-type PbF 2 was observed at high temperature, but the material partially transformed back to the orthorhombic phase upon temperature quench. Our results show that high-pressure behavior of PbF 2 is
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High-pressure polymorphism of Pb F2 to 75 GPa
NASA Astrophysics Data System (ADS)
Stan, Camelia V.; Dutta, Rajkrishna; White, Claire E.; Prakapenka, Vitali; Duffy, Thomas S.
2016-07-01
Lead fluoride, Pb F2 , was investigated experimentally in the laser-heated diamond anvil cell by x-ray diffraction to pressures of 75 GPa at room temperature and to 64.5 GPa and 2430 K, as well as through first-principles density functional theory calculations up to 70 GPa. During room temperature compression, no discontinuous changes in the x-ray diffraction pattern or volume were observed, but the lattice parameters displayed highly anomalous trends between 10-22 GPa with enhanced compressibility along the a direction and reduced or even negative compressibility along b and c . Theoretical calculations of valence electron densities at 22 GPa showed that α -Pb F2 underwent a pressure-induced isosymmetric phase transition to a postcotunnite C o2Si structure and also revealed the detailed atomic rearrangements associated with the development of an extra Pb-F bond in the high-pressure phase. Our x-ray results and theoretical calculations are consistent with an isosymmetric phase transition smoothly occurring over 10-22 GPa rather than abruptly as previously suggested. The characteristic values for the cell constants a /c and (a +c )/b , which are used to distinguish among cotunnite-, C o2Si -, and N i2In -type phases, require modification based on our results. An equation of state fit yields a bulk modulus, K0, of 72(3) GPa for the cotunnite-type, and an ambient-pressure volume, V0, of 182 (2 ) Å3 , and K0=81 (4 ) GPa for the C o2Si -type phase when fixing the pressure derivative of the bulk modulus, K0 '=4 . Upon heating above 1200 K at pressures at or above 25.9 GPa, Pb F2 partially transformed to the hexagonal N i2In -type phase but wholly or partially reverted back to C o2Si -type phase upon temperature quench. From 43-65 GPa, nearly complete transformation to the N i2In -type Pb F2 was observed at high temperature, but the material partially transformed back to the orthorhombic phase upon temperature quench. Our results show that high-pressure behavior of Pb F
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High-pressure studies of cycloheptane up to 30 GPa
NASA Astrophysics Data System (ADS)
Ma, Chunli; Cui, Qiliang; Liu, Zhenxian
2013-06-01
High-pressure synchrotron angle dispersive x-ray diffraction, Raman scattering and infrared absorption studies have been performed on cycloheptane (C7H14) up to 30 GPa at room temperature by using diamond anvil cell techniques. The synchrotron x-ray diffraction results indicate that the liquid cyclopentane undergoes two phase transitions at around 0.5 and 1.0 GPa, respectively. Then, it gradually turns into glass state starting from 3.0 GPa. The features of the Raman scattering and infrared absorption show no significant changes with increasing pressure below 3 GPa. This implies that the two phases observed by the x-ray diffraction can be attributed to plastic phases in which the cycloheptane molecules are held in an ordered structure while the molecular orientation is disordered. Up on further compression, all Raman and infrared bands begin broadening around 3.0 GPa that provide further evidence on the transition to glass state. Our results also suggest different paths on phase transitions under isothermal compression at room temperature compare to that previously reported under isobaric cooling at ambient pressure. This work was supported by the NSF of China (91014004, 11004074,11074089), the specialized Research Fund for the Doctoral Program of Higher Education (20110061110011, 20100061120093), and the National Basic Research Program of China (2011CB808200).
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The Why, What, and Impact of GPA at Oxford Brookes University
ERIC Educational Resources Information Center
Andrews, Matthew
2016-01-01
This paper examines the introduction at Oxford Brookes University of a Grade Point Average (GPA) scheme alongside the traditional honours degree classification. It considers the reasons for the introduction of GPA, the way in which the scheme was implemented, and offers an insight into the impact of GPA at Brookes. Finally, the paper considers…
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Li, Xianran; Tian, Feng; Huang, Haiyan; Tan, Lubin; Zhu, Zuofeng; Hu, Songnian; Sun, Chuanqing
2008-06-01
To facilitate cloning gene(s) underlying gpa7, a deep-coverage BAC library was constructed for an isolate of common wild rice (Oryza rufipogon Griff.) collected from Dongxiang, Jiangxi Province, China (DXCWR). gpa7, a quantitative trait locus corresponding to grain number per panicle, is positioned in the short arm of chromosome 7. The BAC library containing 96,768 clones represents approximate 18 haploid genome equivalents. The contig spanning DXCWR gpa7 was constructed with a series of ordered markers. The putative physical map near the gpa7 locus of another accession of O. rufipogon (Accession: IRGC 105491) was also isolated in silico. Analysis of the physical maps of gpa7 indicated that a segment of about 150 kb was deleted during domestication of common wild rice.
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X-ray diffraction study of elemental erbium to 70 GPa
NASA Astrophysics Data System (ADS)
Pravica, Michael G.; Romano, Edward; Quine, Zachary
2005-12-01
We have investigated phase transitions in elemental erbium in a diamond anvil cell (DAC) up to 70GPa using angular-dispersive x-ray powder diffraction methods. We present evidence of a series of phase transitions that appear to follow the anticipated hcp→Sm-type→doublehcp(dhcp)→distorted fcc sequence. In particular, we present evidence for the predicted dhcp→distorted fcc transition above 63GPa . Equation of state data are also presented up to 70GPa .
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Transformation of hydrazinium azide to molecular N8 at 40 GPa
NASA Astrophysics Data System (ADS)
Duwal, Sakun; Ryu, Young-Jay; Kim, Minseob; Yoo, Choong-Shik; Bang, Sora; Kim, Kyungtae; Hur, Nam Hwi
2018-04-01
Hydrazinium azide (HA) has been investigated at high pressures to 68 GPa using confocal micro-Raman spectroscopy and synchrotron powder x-ray diffraction. The results show that HA undergoes structural phase transitions from solid HA-I to HA-II at 13 GPa, associated with the strengthening of hydrogen bonding, and then to N8 at 40 GPa. The transformation of HA to recently predicted N8 (N≡N+—N-—N=N—-N—+N≡N) is evident by the emergence of new peaks at 2384 cm-1, 1665 cm-1, and 1165 cm-1, arising from the terminal N≡N stretching, the central N=N stretching, and the N—N stretching, respectively. However, upon decompression, N8 decomposes to ɛ-N2 below 25 GPa, but the remnant can be seen as low as 3 GPa.
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X-ray diffraction study of elemental erbium to 70 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pravica, Michael G.; Romano, Edward; Quine, Zachary
2005-12-01
We have investigated phase transitions in elemental erbium in a diamond anvil cell (DAC) up to 70 GPa using angular-dispersive x-ray powder diffraction methods. We present evidence of a series of phase transitions that appear to follow the anticipated hcp{yields}Sm-type{yields}double hcp (dhcp){yields}distorted fcc sequence. In particular, we present evidence for the predicted dhcp{yields}distorted fcc transition above 63 GPa. Equation of state data are also presented up to 70 GPa.
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Challenging the 3.0 GPA Eligibility Standard for Public Relations Internships.
ERIC Educational Resources Information Center
Maynard, Michael L.
1999-01-01
Analyzes the appropriateness of a 3.0 GPA standard for public relations internship eligibility at one university. Seeks to determine at what GPA cutoff faculty can feel confident that the student will gain from the internship without damaging the program's reputation. Finds students with a 2.7 GPA did as well as students with GPAs ranging from 3.0…
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40 CFR 80.220 - What are the downstream standards for GPA gasoline?
Code of Federal Regulations, 2014 CFR
2014-07-01
... GPA gasoline? 80.220 Section 80.220 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.220 What are the downstream standards for GPA gasoline? (a) GPA gasoline. (1) During...
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40 CFR 80.220 - What are the downstream standards for GPA gasoline?
Code of Federal Regulations, 2010 CFR
2010-07-01
... GPA gasoline? 80.220 Section 80.220 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.220 What are the downstream standards for GPA gasoline? (a) GPA gasoline. (1) During...
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40 CFR 80.220 - What are the downstream standards for GPA gasoline?
Code of Federal Regulations, 2013 CFR
2013-07-01
... GPA gasoline? 80.220 Section 80.220 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.220 What are the downstream standards for GPA gasoline? (a) GPA gasoline. (1) During...
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40 CFR 80.220 - What are the downstream standards for GPA gasoline?
Code of Federal Regulations, 2012 CFR
2012-07-01
... GPA gasoline? 80.220 Section 80.220 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.220 What are the downstream standards for GPA gasoline? (a) GPA gasoline. (1) During...
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40 CFR 80.220 - What are the downstream standards for GPA gasoline?
Code of Federal Regulations, 2011 CFR
2011-07-01
... GPA gasoline? 80.220 Section 80.220 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.220 What are the downstream standards for GPA gasoline? (a) GPA gasoline. (1) During...
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GPA in Research Studies: An Invaluable but Neglected Opportunity
ERIC Educational Resources Information Center
Bacon, Donald R.; Bean, Beth
2006-01-01
Grade point average (GPA) often correlates highly with variables of interest to educational researchers and thus offers the potential to greatly increase the statistical power of their research studies. Yet this variable is often underused in marketing education research studies. The reliability and validity of the GPA are closely examined here in…
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Diffusivity of hydrogen in iron-bearing olivine at 3 GPa
NASA Astrophysics Data System (ADS)
Demouchy, Sylvie; Thoraval, Catherine; Bolfan-Casanova, Nathalie; Manthilake, Geeth
2016-11-01
The kinetics of hydrogenation of dry iron-bearing olivine single crystals was determined by performing hydration experiments under hydrothermal conditions at high pressure. The experiments were performed in a multi-anvil press at 3 GPa, for a temperature range between 900 and 1200 °C and for various durations. The oxygen fugacity was buffered along Ni-NiO joint. Polarized Fourier transform infrared spectroscopy and recent empirical calibration were used to quantify the hydroxyl distributions in the samples along crystallographic axes after the experiments. The chemical diffusion coefficients are similar (barely slower) than in olivine hydrated at lower pressure (0.2 and 0.3 GPa) for the same diffusion mechanism. Under the given experimental conditions, the anisotropy of diffusion is the same as for proton-vacancy mechanism, with diffusion along the [0 0 1] axis faster than along the [1 0 0]. However, the anisotropy at 3 GPa is weaker compared to measurements at lower pressures and the analysis of concentration profiles using 3D models shows that an isotropic solution could also be relevant. Fits of the diffusion data to an Arrhenius law yield activation energies for the slightly faster [0 0 1] axis of the crystallographic axes around 198 ± 5 kJ mol-1, a value only slightly lower than the results from previous experimental studies for natural iron-bearing olivine hydrogenated at lower confining pressure. At 3 GPa, hydrogenation can be well approximated by a single mechanism controlled by coupled diffusion of protons and octahedral vacancies (di- and tri-valent ions). The diffusion rates are fast enough to alter hydrogen concentration within olivine in xenoliths ascending from the mantle or experiencing hydrogen-rich metasomatism events, but too slow to permit complete homogenization of hydrogen in olivine-rich rocks at kilometer scale in less than one My.
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NASA Technical Reports Server (NTRS)
Meade, Charles; Jeanloz, Raymond
1990-01-01
X-ray diffraction measurements are reported for Ca(OH)2 portlandite as it is compressed to 37.6 GPa in the diamond cell at room temperature. Between 10.7 and 15.4 GPa crystalline Ca(OH)2 transforms to a glass, and on decompression the glass recrystallizes between 3.6 and 5.1 GPa. Below pressures of 10.7 GPa the elastic compression of crystalline Ca(OH)2 was measured. A finite strain analysis of these data shows that the isothermal bulk modulus and its pressure derivative are 37.8 + or - 1.8 GPa and 5.2 + or - 0.7 at zero pressure. The change in the unit cell dimensions indicates that the linear incompressibilities of Ca(OH)2 differ by a factor of three.
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Compressional behavior of omphacite to 47 GPa
Zhang, Dongzhou; Hu, Yi; Dera, Przemyslaw K.
2016-07-08
Omphacite is an important mineral component of eclogite. Single crystal synchrotron X-ray diffraction data on natural (Ca,Na)(Mg,Fe,Al)Si 2O 6 omphacite have been collected at the Advanced Photon Source beamlines 13-BM-C and 13-ID-D up to 47 GPa at ambient temperature. Unit cell parameter and crystal structure refinements were carried out to constrain the isothermal equation of state and compression mechanism. The 3rd order Birch-Murnaghan equation of state (BM3) fit of all data gives V o = 423.9(3) Å3, K To = 116(2) GPa and K To’ = 4.3(2). These elastic parameters are consistent with the general trend of the diopside-jadeite join.more » The eight-coordinated polyhedra (M2 and M21) are the most compressible, and contribute to majority of the unit cell compression, while the SiO 4 tetrahedra (Si1 and Si2) behave as rigid structural units and are the most incompressible. Axial compressibilities are determined by fitting linearized BM 3 equation of state to pressure dependences of unit cell parameters. Throughout the investigated pressure range, the b-axis is more compressible than the c-axis. Here, the axial compressibility of the α-axis is the largest among the three axes at 0 GPa, yet it quickly drops to the smallest at pressures above 5 GPa, which is explained by the rotation of the stiffest compression axis toward the a-axis with the increase of pressure.« less
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SAT and ACT Predict College GPA after Removing "g"
ERIC Educational Resources Information Center
Coyle, Thomas R.; Pillow, David R.
2008-01-01
This research examined whether the SAT and ACT would predict college grade point average (GPA) after removing g from the tests. SAT and ACT scores and freshman GPAs were obtained from a university sample (N=161) and the 1997 National Longitudinal Study of Youth (N=8984). Structural equation modeling was used to examine relationships among g, GPA,…
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NASA Astrophysics Data System (ADS)
Li, Bo; Nan, Yanli; Zhao, Xiang; Song, Xiaolong; Li, Haining; Wu, Jie; Su, Lei
2017-11-01
We report a high-pressure behavior of carbon nanohorns (CNHs) to 40 GPa at ambient temperature by in situ Raman spectroscopy and synchrotron radiation x-ray diffraction (XRD) in a diamond anvil cell. In Raman measurement, multiple structural transitions are observed. In particular, an additional band at ˜1540 cm-1 indicative of sp3 bonding is shown above 35 GPa, but it reverses upon releasing pressure, implying the formation of a metastable carbon phase having both sp2 and sp3 bonds. Raman frequencies of all bands (G, 2D, D + G, and 2D') are dependent upon pressure with respective pressure coefficients, among which the value for the G band is as small as ˜2.65 cm-1 GPa-1 above 10 GPa, showing a superior high-pressure structural stability. Analysis based on mode Grüneisen parameter demonstrates the similarity of high-pressure behavior between CNHs and single-walled carbon nanotubes. Furthermore, the bulk modulus and Grüneisen parameter for the G band of CNHs are calculated to be ˜33.3 GPa and 0.1, respectively. In addition, XRD data demonstrate that the structure of post-graphite phase derives from surface nanohorns. Based on topological defects within conical graphene lattice, a reasonable transformation route from nanohorns to the post-graphite phase is proposed.
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Structural and electronic evolution of Cr[subscript 2]O[subscript 3] on compression to 55 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dera, Przemyslaw; Lavina, Barbara; Meng, Yue
2016-08-15
Synchrotron single-crystal x-ray diffraction experiments have been performed on corundum-type Cr{sub 2}O{sub 3} up to a pressure of 55 GPa in Ne and He pressure transmitting media. Diffraction experiments were complemented by measurements of optical absorption spectra with single crystal samples up to 60 GPa. Results of the diffraction data analysis rule out the earlier reported monoclinic distortion at 15-30 GPa, but indicate evidence of two discontinuous transitions of electronic or magnetic nature, most likely associated with a change in magnetic ordering and charge transfer. The compression mechanism established from single crystal refinements indicates much smaller distortion of the Cr{supmore » 3+} coordination environment than was previously assumed.« less
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Phase Transitions and Melting in Magnesium to 200 GPa and 4500 K
NASA Astrophysics Data System (ADS)
Stinton, G.; MacLeod, S.; Cynn, H.; Errandonea, D.; Proctor, J.; Meng, Y.; McMahon, M.
2013-06-01
Magnesium is a ``simple'' nearly free-electron metal up to around 100 GPa. Despite similarly-simple group II metals being the subject of numerous studies that have revealed complex high-pressure behaviour, Mg has very few high-pressure diffraction studies, particularly above room temperature. Here we describe such studies to above 200 GPa at 300 K, combined with resistive- and laser-heating experiments to 4500 K and 100 GPa. The hcp-bcc transition at ~50 GPa exhibits a large region of phase co-existence at all temperatures up to 800 K, and the transition pressure is found to decrease with temperature at the rate of ~3.4 GPa per 100 K, somewhat smaller than the rate calculated by Mehta et al.,. At lower pressures, below the melting curve at 10 GPa, we find the dhcp phase to be stable, in agreement with Errandonea et al.. Laser heating studies to 4500 K and 100 GPa show that Mg remains bcc up to the melting curve, our measurement of which is in good agreement with the previous ``speckle'' studies of Errandonea et al.. This work was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344.
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Dynamic compression of copper to over 450 GPa: A high-pressure standard
Kraus, R. G.; Davis, J. -P.; Seagle, C. T.; ...
2016-04-12
We obtained an absolute stress-density path for shocklessly compressed copper to over 450 GPa. A magnetic pressure drive is temporally tailored to generate shockless compression waves through over 2.5-mm-thick copper samples. Furthermore, the free-surface velocity data is analyzed for Lagrangian sound velocity using the iterative Lagrangian analysis (ILA) technique, which relies upon the method of characteristics. We correct for the effects of strength and plastic work heating to determine an isentropic compression path. By assuming a Debye model for the heat capacity, we can further correct the isentrope to an isotherm. Finally, our determination of the isentrope and isotherm ofmore » copper represents a highly accurate pressure standard for copper to over 450 GPa.« less
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NASA Technical Reports Server (NTRS)
Rao, M. N.; Ross, D. K.; See, T. H.; Nyquist, L. E.; Sutton, S.; Asimow, P.
2013-01-01
Large abundance of Martian atmospheric gases and neutron-induced isotopic excesses as well as Rb-Sr isotopic variations determined in some impact glasses in basaltic shergottites (e.g., Shergotty #DBS, Zagami #H1 and EET79001 #27, #8 and #104) provide definitive evidence for the occurrence of a Martian regolith component in their constituent mineral assemblages. Some of these glass-es, known as gas-rich impact-melts (GRIM), contain numerous micron-sized iron sulfide blebs along with minor amounts of iron sulfate particulates. As these GRIM glasses contain a Martian regolith component and as iron sulfates (but not sulfides) are found to occur abundantly on the Mars surface, we suggested that the sulfide blebs in GRIMs were likely generated by shock-reduction of the parental iron sulfate bearing regolith material that had been incorporated into the cavities/crevices of basaltic host rock prior to the impact event on Mars. To test whether the sulfates could be reduced to sulfides by impact shock, we carried out laboratory shock experiments on a basalt plus ferric sulfate mixture at 49 GPa at the Caltech Shock Wave Laboratory and at 21 GPa at Johnson Space Center (JSC) Experimental Impact Laboratory. The experimental details and the preliminary results for the Caltech 49 GPa experiment were presented at LPSC last year. Here, we report the results for the 21 GPa experiment at JSC and compare these results to obtain further insight into the mechanism of the bleb formation in the GRIM glasses.
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Compressibility of one glass and two glass ceramics to 4 GPa
NASA Astrophysics Data System (ADS)
Sigalas, I.; Auret, J. G.; Hart, S.
1986-05-01
By monitoring the piston dispacement, up to 4 GPa, in a static high pressure piston-cylinder apparatus the volume compression of Duran 50 glass, Macor machinable glass ceramic and CER-VIT C101 glass ceramic was determined. It was established that the compressibility of Duran 50 increases with pressure up to 4 GPa. The values obtained for CER-VIT C101 indicate that, at about 0.8 GPa, the structure of this material transforms to low quartz.
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Structural phase stability in nanocrystalline titanium to 161 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Velisavljevic, Nenad; Jacobsen, Matthew K.; Vohra, Yogesh K.
2014-09-16
Nanocrystalline titanium (nc-Ti) metal was investigated up to 161 GPa at room temperature using a diamond anvil cell. X-ray diffraction and electrical resistance techniques were used to investigate the compressibility and structural phase stability. nc-Ti is observed to undergo three structural phase transitions at high pressures, starting with α → ω at 10GPa and followed by ω → γ at 127GPa and γ → δ at 140GPa. The observed structural phase transitions, as well as compressibility, are consistent with previously reported values for coarse grained Ti (c-Ti). The high pressure experiments on nc-Ti samples do no show any significant variationmore » of the α → ω transition pressure under varying nonhydrostatic conditions. This is in sharp contrast to c-Ti, where a significant decrease in the α → ω transition pressure is observed under increasing nonhydrostatic conditions. As a result, this would indicate that the decrease in grain size in nano grained titanium makes the α → ω phase transition less sensitive to shear stresses as compared to bulk or c-Ti.« less
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Structural Transitions in Elemental Tin at Ultra High Pressures up to 230 GPa
NASA Astrophysics Data System (ADS)
Gavriliuk, A. G.; Troyan, I. A.; Ivanova, A. G.; Aksenov, S. N.; Starchikov, S. S.; Lyubutin, I. S.; Morgenroth, W.; Glazyrin, K. V.; Mezouar, M.
2017-12-01
The crystal structure of elemental Sn was investigated by synchrotron X-ray diffraction at ultra high pressures up to ˜230 GPa creating in diamond anvil cells. Above 70 GPa, a pure bcc structure of Sn was observed, which is stable up to 160GPa, until an occurrence of the hcp phase was revealed. At the onset of the bcc- hcp transition at pressure of about 160GPa, the drop of the unit cell volume is about 1%. A mixture of the bcc- hcp states was observed at least up to 230GPa, and it seems that this state could exist even up to higher pressures. The fractions of the bcc and hcp phases were evaluated in the pressure range of the phase coexistence 160-230 GPa. The difference between static and dynamic compression and its effect on the V- P phase diagram of Sn are discussed.
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High Pressure Crystalline Structure and Resistance of Vanadium Dioxide to 13.5 GPa
NASA Astrophysics Data System (ADS)
Brady, Nathaniel; Appavoo, Kannatassen; Montgomery, Jeffery; Vohra, Yogesh; Haglund, Richard; Hilton, David
2013-03-01
We have investigated the insulator-to-metal transition in thin film vanadium dioxide as a function of pressure at ambient temperature using a designer diamond anvil cell (DAC). Four-point probe resistance measurements show a monotonic decrease over the entire pressure range studied with no significant discontinuity. High-pressure X-ray diffraction measurements observe an M1 (P21 / c) phase at 0 GPa, an M2 (C2/m) phase from 0.8 GPa to 1.1 GPa, and a reentrant M1 phase from 1.1 GPa to 13.5 GPa. Crystal refinement above 1.1 GPa shows a monotonically decreasing a, b and c lattice constants and a minimum in the monoclinic angle, β, near 8.5 +/-0.5 GPa. The atomic positions show that the first V-V nearest neighbor distance (d) decreases over the entire pressure range, the second nearest neighbor distance (s) increases until 5 GPa after which it is constant with s ~ f ~3.2 Å. The next most closely spaced V-V distance (f), which corresponds to V atoms in different unit cells, is approximately constant across the entire pressure range measured. NB and JM acknowledge support from the US Dept. Education GAANN Fellowship (P200A090143). KA and RH acknowledge support from the Office of Science, US Department of Energy (DE- FG02-01ER45916).
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Synthesis of bulk chromium hydrides under pressure of up to 120 GPa
NASA Astrophysics Data System (ADS)
Marizy, Adrien; Geneste, Grégory; Loubeyre, Paul; Guigue, Bastien; Garbarino, Gaston
2018-05-01
Stable compounds in the Cr-H system have been synthesized through a direct reaction of chromium and hydrogen in a laser-heated diamond-anvil cell and investigated using synchrotron x-ray diffraction up to 120 GPa . The sequence of hydrides CrH, Cr2H3 , and CrH2 has been observed by increasing pressure. The known ɛ -h c p -CrH hydride is formed above 3 GPa . A Cr2H3 hydride with a C 2 /m structure appears spontaneously above 19 GPa , as a result of the filling of the tetrahedral sites of ɛ -CrH. YAG laser heating helps dissolve more hydrogen inside the h c p chromium structure to synthesize a CrH2 compound with a P n m a structure from 30 GPa on. The volume expansion per hydrogen atom in octahedral and tetrahedral sites is measured up to the 100-GPa pressure range. The formation pressures and structures of these chromium interstitial hydrides are in very good agreement with DFT calculations. However, despite multiple heating attempts up to 100 GPa , no evidence of the stability of the predicted CrH3 compound could be found.
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High-pressure phase transitions in rare earth metal thulium to 195 GPa.
Montgomery, Jeffrey M; Samudrala, Gopi K; Tsoi, Georgiy M; Vohra, Yogesh K
2011-04-20
We have performed image plate x-ray diffraction studies on a heavy rare earth metal, thulium (Tm), in a diamond anvil cell to a pressure of 195 GPa and volume compression V/V₀ = 0.38 at room temperature. The rare earth crystal structure sequence, hcp →Sm-type→ dhcp →fcc → distorted fcc, is observed in Tm below 70 GPa with the exception of a pure fcc phase. The focus of our study is on the ultrahigh-pressure phase transition and Rietveld refinement of crystal structures in the pressure range between 70 and 195 GPa. The hexagonal hR-24 phase is seen to describe the distorted fcc phase between 70 and 124 GPa. Above 124 ± 4 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of -1.5%. The equation of state data shows rapid stiffening above the phase transition at 124 GPa and is indicative of participation of f-electrons in bonding. We compare the behavior of Tm to other heavy rare-earths and heavy actinide metals under extreme conditions of pressure.
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High-pressure phase transitions in rare earth metal thulium to 195 GPa
NASA Astrophysics Data System (ADS)
Montgomery, Jeffrey M.; Samudrala, Gopi K.; Tsoi, Georgiy M.; Vohra, Yogesh K.
2011-04-01
We have performed image plate x-ray diffraction studies on a heavy rare earth metal, thulium (Tm), in a diamond anvil cell to a pressure of 195 GPa and volume compression V/Vo = 0.38 at room temperature. The rare earth crystal structure sequence, {hcp}\\to {Sm {-}type} \\to {dhcp} \\to {fcc} \\to distorted fcc, is observed in Tm below 70 GPa with the exception of a pure fcc phase. The focus of our study is on the ultrahigh-pressure phase transition and Rietveld refinement of crystal structures in the pressure range between 70 and 195 GPa. The hexagonal hR- 24 phase is seen to describe the distorted fcc phase between 70 and 124 GPa. Above 124 ± 4 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of - 1.5%. The equation of state data shows rapid stiffening above the phase transition at 124 GPa and is indicative of participation of f-electrons in bonding. We compare the behavior of Tm to other heavy rare-earths and heavy actinide metals under extreme conditions of pressure.
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Compression of Single-Crystal Orthopyroxene to 60GPa
NASA Astrophysics Data System (ADS)
Finkelstein, G. J.; Dera, P. K.; Holl, C. M.; Dorfman, S. M.; Duffy, T. S.
2010-12-01
Orthopyroxene ((Mg,Fe)SiO3) is one of the dominant phases in Earth’s upper mantle - it makes up ~20% of the upper mantle by volume. At high pressures and temperatures, this phase undergoes several well-characterized phase transitions. However, when compressed at low temperature and high-pressure, orthopyroxene is predicted to exhibit metastable behavior(1). Previous researchers have found orthoenstatite (Mg endmember of orthopyroxene) persists up to ~10 GPa, and diffraction(2-3), Raman(4), and elasticity(5) experiments suggest a phase transition above this pressure to an as-yet unidentified structure. While earlier diffraction data has surprisingly only been evaluated for structural information to ~9 GPa(2), changes in high-pressure Raman spectra to ~70 GPa indicate that several more high-pressure phase transitions in orthopyroxene are likely, including at least one change in Si-coordination(6). We have recently conducted exploratory experiments to further elucidate the high-pressure behavior of orthopyroxene. Compressing a single crystal of Fe-rich orthopyroxene (Fe0.66Mg0.24Ca0.05SiO3) using a diamond anvil cell, we observe phase transitions at ~10, 14, and 30 GPa, with the new phases having monoclinic, orthorhombic, and orthorhombic symmetries, respectively. While the first two transitions do not show a significant change in volume, the phase transition at ~30 GPa shows a large decrease in volume, which is consistent with a change in Si coordination number to mixed 4- and 6-fold coordination. References: [1] S. Jahn, American Mineralogist 93, 528-532 (2008). [2] R. J. Angel, J. M. Jackson, American Mineralogist 87, 558-561 (2002). [3] R. J. Angel, D. A. Hugh-Jones, Journal of Geophysical Research-Solid Earth 99, 19,777-19,783 (1994). [4] G. Serghiou, Journal of Raman Spectroscopy 34, 587-590 (2003). [5] J. Kung et al., Physics of the Earth and Planetary Interiors 147, 27-44 (2004). [6] G. Serghiou, A. Chopelas, R. Boehler, Journal of Physics: Condensed
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Photometric calibration of the COMBO-17 survey with the Softassign Procrustes Matching method
NASA Astrophysics Data System (ADS)
Sheikhbahaee, Z.; Nakajima, R.; Erben, T.; Schneider, P.; Hildebrandt, H.; Becker, A. C.
2017-11-01
Accurate photometric calibration of optical data is crucial for photometric redshift estimation. We present the Softassign Procrustes Matching (SPM) method to improve the colour calibration upon the commonly used Stellar Locus Regression (SLR) method for the COMBO-17 survey. Our colour calibration approach can be categorised as a point-set matching method, which is frequently used in medical imaging and pattern recognition. We attain a photometric redshift precision Δz/(1 + zs) of better than 2 per cent. Our method is based on aligning the stellar locus of the uncalibrated stars to that of a spectroscopic sample of the Sloan Digital Sky Survey standard stars. We achieve our goal by finding a correspondence matrix between the two point-sets and applying the matrix to estimate the appropriate translations in multidimensional colour space. The SPM method is able to find the translation between two point-sets, despite the existence of noise and incompleteness of the common structures in the sets, as long as there is a distinct structure in at least one of the colour-colour pairs. We demonstrate the precision of our colour calibration method with a mock catalogue. The SPM colour calibration code is publicly available at https://neuronphysics@bitbucket.org/neuronphysics/spm.git.
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A General Linear Model Approach to Adjusting the Cumulative GPA.
ERIC Educational Resources Information Center
Young, John W.
A general linear model (GLM), using least-squares techniques, was used to develop a criterion measure to replace freshman year grade point average (GPA) in college admission predictive validity studies. Problems with the use of GPA include those associated with the combination of grades from different courses and disciplines into a single measure,…
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Yu, Xiaonan; Liu, Bin; Pei, Yuru; Xu, Tianmin
2014-05-01
To establish an objective method for evaluating facial attractiveness from a set of orthodontic photographs. One hundred eight malocclusion patients randomly selected from six universities in China were randomly divided into nine groups, with each group containing an equal number of patients with Class I, II, and III malocclusions. Sixty-nine expert Chinese orthodontists ranked photographs of the patients (frontal, lateral, and frontal smiling photos) before and after orthodontic treatment from "most attractive" to "least attractive" in each group. A weighted mean ranking was then calculated for each patient, based on which a three-point scale was created. Procrustes superimposition was conducted on 101 landmarks identified on the photographs. A support vector regression (SVR) function was set up according to the coordinate values of identified landmarks of each photographic set and its corresponding grading. Its predictive ability was tested for each group in turn. The average coincidence rate obtained for comparisons of the subjective ratings with the SVR evaluation was 71.8% according to 18 verification tests. Geometric morphometrics combined with SVR may be a prospective method for objective comprehensive evaluation of facial attractiveness in the near future.
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Phase stability of iron germanate, FeGeO3, to 127 GPa
NASA Astrophysics Data System (ADS)
Dutta, R.; Tracy, S. J.; Stan, C. V.; Prakapenka, V. B.; Cava, R. J.; Duffy, T. S.
2018-04-01
The high-pressure behavior of germanates is of interest as these compounds serve as analogs for silicates of the deep Earth. Current theoretical and experimental studies of iron germanate, FeGeO3, are limited. Here, we have examined the behavior of FeGeO3 to 127 GPa using the laser-heated diamond anvil cell combined with in situ synchrotron X-ray diffraction. Upon compression at room temperature, the ambient-pressure clinopyroxene phase transforms to a disordered triclinic phase [FeGeO3 (II)] at 18 GPa in agreement with earlier studies. An additional phase transition to FeGeO3 (III) occurs above 54 GPa at room temperature. Laser-heating experiments ( 1200-2200 K) were conducted at three pressures (33, 54, and 123 GPa) chosen to cover the stability regions of different GeO2 polymorphs. In all cases, we observe that FeGeO3 dissociates into GeO2 + FeO at high pressure and temperature conditions. Neither the perovskite nor the post-perovskite phase was observed up to 127 GPa at ambient or high temperatures. The results are consistent with the behavior of FeSiO3, which also dissociates into a mixture of the oxides (FeO + SiO2) at least up to 149 GPa.
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X-ray-diffraction study of californium metal to 16 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Peterson, J.R.; Benedict, U.; Dufour, C.
1983-01-01
The first series of measurements to determine the structural behavior of californium (Cf) metal under pressure has been carried out. The initial dhcp structure transformed sluggishly with increasing pressure to a fcc structure. A bulk modulus of 50(5) GPa was derived for dhcp Cf metal from the relative volume (V/V/sub 0/) data to 10 GPa.
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40 CFR 80.219 - Designation and downstream requirements for GPA gasoline.
Code of Federal Regulations, 2011 CFR
2011-07-01
... requirements for GPA gasoline. 80.219 Section 80.219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.219 Designation and downstream requirements for GPA gasoline. The requirements and...
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40 CFR 80.219 - Designation and downstream requirements for GPA gasoline.
Code of Federal Regulations, 2010 CFR
2010-07-01
... requirements for GPA gasoline. 80.219 Section 80.219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.219 Designation and downstream requirements for GPA gasoline. The requirements and...
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40 CFR 80.219 - Designation and downstream requirements for GPA gasoline.
Code of Federal Regulations, 2014 CFR
2014-07-01
... requirements for GPA gasoline. 80.219 Section 80.219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.219 Designation and downstream requirements for GPA gasoline. The requirements and...
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40 CFR 80.219 - Designation and downstream requirements for GPA gasoline.
Code of Federal Regulations, 2012 CFR
2012-07-01
... requirements for GPA gasoline. 80.219 Section 80.219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.219 Designation and downstream requirements for GPA gasoline. The requirements and...
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40 CFR 80.219 - Designation and downstream requirements for GPA gasoline.
Code of Federal Regulations, 2013 CFR
2013-07-01
... requirements for GPA gasoline. 80.219 Section 80.219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.219 Designation and downstream requirements for GPA gasoline. The requirements and...
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Carbon nanotube bundles with tensile strength over 80 GPa.
Bai, Yunxiang; Zhang, Rufan; Ye, Xuan; Zhu, Zhenxing; Xie, Huanhuan; Shen, Boyuan; Cai, Dali; Liu, Bofei; Zhang, Chenxi; Jia, Zhao; Zhang, Shenli; Li, Xide; Wei, Fei
2018-05-14
Carbon nanotubes (CNTs) are one of the strongest known materials. When assembled into fibres, however, their strength becomes impaired by defects, impurities, random orientations and discontinuous lengths. Fabricating CNT fibres with strength reaching that of a single CNT has been an enduring challenge. Here, we demonstrate the fabrication of CNT bundles (CNTBs) that are centimetres long with tensile strength over 80 GPa using ultralong defect-free CNTs. The tensile strength of CNTBs is controlled by the Daniels effect owing to the non-uniformity of the initial strains in the components. We propose a synchronous tightening and relaxing strategy to release these non-uniform initial strains. The fabricated CNTBs, consisting of a large number of components with parallel alignment, defect-free structures, continuous lengths and uniform initial strains, exhibit a tensile strength of 80 GPa (corresponding to an engineering tensile strength of 43 GPa), which is far higher than that of any other strong fibre.
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Paluzzi, Jean-Paul; Vanderveken, Mark; O’Donnell, Michael J.
2014-01-01
A family of evolutionarily old hormones is the glycoprotein cysteine knot-forming heterodimers consisting of alpha- (GPA) and beta-subunits (GPB), which assemble by noncovalent bonds. In mammals, a common glycoprotein hormone alpha-subunit (GPA1) pairs with unique beta-subunits that establish receptor specificity, forming thyroid stimulating hormone (GPA1/TSHβ) and the gonadotropins luteinizing hormone (GPA1/LHβ), follicle stimulating hormone (GPA1/FSHβ), choriogonadotropin (GPA1/CGβ). A novel glycoprotein heterodimer was identified in vertebrates by genome analysis, called thyrostimulin, composed of two novel subunits, GPA2 and GPB5, and homologs occur in arthropods, nematodes and cnidarians, implying that this neurohormone system existed prior to the emergence of bilateral metazoans. In order to discern possible physiological roles of this hormonal signaling system in mosquitoes, we have isolated the glycoprotein hormone genes producing the alpha- and beta-subunits (AedaeGPA2 and AedaeGPB5) and assessed their temporal expression profiles in the yellow and dengue-fever vector, Aedes aegypti. We have also isolated a putative receptor for this novel mosquito hormone, AedaeLGR1, which contains features conserved with other glycoprotein leucine-rich repeating containing G protein-coupled receptors. AedaeLGR1 is expressed in tissues of the alimentary canal such as the midgut, Malpighian tubules and hindgut, suggesting that this novel mosquito glycoprotein hormone may regulate ionic and osmotic balance. Focusing on the hindgut in adult stage A. aegypti, where AedaeLGR1 was highly enriched, we utilized the Scanning Ion-selective Electrode Technique (SIET) to determine if AedaeGPA2/GPB5 modulated cation transport across this epithelial tissue. Our results suggest that AedaeGPA2/GPB5 does indeed participate in ionic and osmotic balance, since it appears to inhibit natriuresis and promote kaliuresis. Taken together, our findings imply this hormone may play an important
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NASA Astrophysics Data System (ADS)
Andrault, D.; Bolfan-Casanova, N.; Ohtaka, O.; Fukui, H.; Arima, H.; Fialin, M.; Funakoshi, K.
2009-05-01
We report in situ observations of the melting behaviour of iron alloyed with 10-20 at.% C, O, S, or Si at pressures between 15 and 24 GPa, using X-ray diffraction in a multi-anvil press (SPring8). The degree of partial melting of the iron alloys has been quantified from analysis of the intensity of diffuse X-ray scattering of molten iron as a function for decreasing temperature with a 50° step. Coupled with microanalysis of recovered samples, the in situ observations bring direct constraints on shape and positions of liquidus and solidus curves in the melting diagrams. For the Fe-S system, our results are in good agreement with previous works. We observe that the eutectic temperature increases from 1023 K at 15 GPa to 1123 K at 20.6 GPa and that the eutectic composition decreases with increases pressure. Concerning the Fe-C system the eutectic temperature of 1460 K at 20.7 GPa falls slightly below a linear extrapolation of the previous work. In the case of the Fe-Ni-Si system and the Fe-O system, we find eutectic temperatures significantly lower than previously reported. For the two systems, both eutectic temperature and composition increase with increasing pressure in the 15-20 GPa range. Compare to previous work, we observe eutectic compositions (a) richer in light elements in the Fe-O system, with 9.0 and 10.5 wt% O at 16.5 and 20.5 GPa, respectively, and (b) poorer in the Fe-Ni-Si system with 11.5 wt% Si at 16.9 GPa. We confirm very high solubility of Si and C with solid iron, and report a Si partitioning coefficient of 1.3(2) at 16.9 GPa. The S and O solubility in solid iron appears very small. Therefore, both S and/or O could explain density jumps between liquid outer and solid inner parts of planetary cores, at least up to ˜25 GPa.
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ERIC Educational Resources Information Center
Saele, Rannveig Grøm; Sørlie, Tore; Nergård-Nilssen, Trude; Ottosen, Karl-Ottar; Goll, Charlotte Bjørnskov; Friborg, Oddgeir
2016-01-01
Approximately 30% of students drop out from Norwegian upper secondary schools. Academic achievement, as indexed by grade point average (GPA), is one of the strongest predictors of dropout. The present study aimed to examine the role of cognitive, school-related and affective/psychological predictors of GPA. In addition, we examined the…
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Craniofacial morphometric analysis of mandibular prognathism.
Chang, H P; Liu, P H; Yang, Y H; Lin, H C; Chang, C H
2006-03-01
The purpose of this study was to provide more information about the morphological characteristics of the craniofacial complex in mandibular prognathism. Forty young adult males having mandibular prognathism were compared with 40 having normal occlusion. This was conducted to carry out geometric morphometric assessments to localize alterations, using Procrustes analysis and thin-plate spline analysis, in addition to conventional cephalometric techniques. Procrustes analysis indicated that the mean craniofacial, midfacial and mandibular morphology was significantly different in prognathic subjects compared with normal controls. This finding was corroborated by the multivariate Hotelling T(2)-test of cephalometric variables. Mandibular prognathism demonstrated a shorter and slightly retropositioned maxilla, a greater total length and anterior positioning of the mandible. Thin-plate spline analysis revealed a developmental diminution of the palatomaxillary region anteroposteriorly and a developmental elongation of the mandible anteroposteriorly, leading to the appearance of a prognathic mandibular profile. In conclusion, thin-plate spline analysis seems to provide a valuable supplement for conventional cephalometric analysis because the complex patterns of craniofacial shape change are visualized suggestive by means of grid deformations.
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Competitiveness: relations with GPA, locus of control, sex, and athletic status.
Frederick, C M
2000-04-01
A sample of college students and college athletes completed measures of competitiveness and locus of control. In addition, self-reports of GPA and sex were provided. Negative correlations among scores on competitiveness, GPA, and scores on internal locus of control were significant. Also, there were sex and athletic status differences in competitiveness.
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Loughlin, Wendy A; Jenkins, Ian D; Karis, N David; Healy, Peter C
2017-02-15
Glycogen Phosphorylase (GP) is a functionally active dimeric enzyme, which is a target for inhibition of the conversion of glycogen to glucose-1-phosphate. In this study we report the design and synthesis of 14 new pyridone derivatives, and seek to extend the SAR analysis of these compounds. The SAR revealed the minor influence of the amide group, importance of the pyridone ring both spatially around the pyridine ring and for possible π-stacking, and confirmed a preference for inclusion of 3,4-dichlorobenzyl moieties, as bookends to the pyridone scaffold. Upon exploring a dimer strategy as part of the SAR analysis, the first extended 2-oxo-dihydropyridinyl-3-yl amide nanomolar based inhibitors of GPa (IC 50 = 230 and 260 nM) were identified. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
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Shape Analysis of 3D Head Scan Data for U.S. Respirator Users
NASA Astrophysics Data System (ADS)
Zhuang, Ziqing; Slice, DennisE; Benson, Stacey; Lynch, Stephanie; Viscusi, DennisJ
2010-12-01
In 2003, the National Institute for Occupational Safety and Health (NIOSH) conducted a head-and-face anthropometric survey of diverse, civilian respirator users. Of the 3,997 subjects measured using traditional anthropometric techniques, surface scans and 26 three-dimensional (3D) landmark locations were collected for 947 subjects. The objective of this study was to report the size and shape variation of the survey participants using the 3D data. Generalized Procrustes Analysis (GPA) was conducted to standardize configurations of landmarks associated with individuals into a common coordinate system. The superimposed coordinates for each individual were used as commensurate variables that describe individual shape and were analyzed using Principal Component Analysis (PCA) to identify population variation. The first four principal components (PC) account for 49% of the total sample variation. The first PC indicates that overall size is an important component of facial variability. The second PC accounts for long and narrow or short and wide faces. Longer narrow orbits versus shorter wider orbits can be described by PC3, and PC4 represents variation in the degree of ortho/prognathism. Geometric Morphometrics provides a detailed and interpretable assessment of morphological variation that may be useful in assessing respirators and devising new test and certification standards.
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Pressure-enhanced ortho-para conversion in solid hydrogen up to 58 GPa.
Eggert, J H; Karmon, E; Hemley, R J; Mao, A; Goncharov, A F
1999-10-26
We measured the ortho-para conversion rate in solid hydrogen by using Raman scattering in a diamond-anvil cell, extending previous measurements by a factor of 60 in pressure. We confirm previous experiments that suggested a decrease in the conversion rate above about 0.5 GPa. We observe a distinct minimum at 3 GPa followed by a drastic increase in the conversion rate to our maximum pressure of 58 GPa. This pressure enhancement of conversion is not predicted by previous theoretical treatments and must be due to a new conversion pathway.
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Pressure-enhanced ortho-para conversion in solid hydrogen up to 58 GPa
Eggert, Jon H.; Karmon, Eran; Hemley, Russell J.; Mao, Ho-kwang; Goncharov, Alexander F.
1999-01-01
We measured the ortho-para conversion rate in solid hydrogen by using Raman scattering in a diamond-anvil cell, extending previous measurements by a factor of 60 in pressure. We confirm previous experiments that suggested a decrease in the conversion rate above about 0.5 GPa. We observe a distinct minimum at 3 GPa followed by a drastic increase in the conversion rate to our maximum pressure of 58 GPa. This pressure enhancement of conversion is not predicted by previous theoretical treatments and must be due to a new conversion pathway. PMID:10535910
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High pressure phase transitions in the rare earth metal erbium to 151 GPa.
Samudrala, Gopi K; Thomas, Sarah A; Montgomery, Jeffrey M; Vohra, Yogesh K
2011-08-10
High pressure x-ray diffraction studies have been performed on the heavy rare earth metal erbium (Er) in a diamond anvil cell at room temperature to a pressure of 151 GPa and Er has been compressed to 40% of its initial volume. The rare earth crystal structure sequence hcp → Sm type → dhcp → distorted fcc (hcp: hexagonal close packed; fcc: face centered cubic; dhcp: double hcp) is observed in Er below 58 GPa. We have carried out Rietveld refinement of crystal structures in the pressure range between 58 GPa and 151 GPa. We have examined various crystal structures that have been proposed for the distorted fcc (dfcc) phase and the post-dfcc phase in rare earth metals. We find that the hexagonal hR 24 structure is the best fit between 58 and 118 GPa. Above 118 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of - 1.9%. We have also established a clear trend for the pressure at which a post-dfcc phase is formed in rare earth metals and show that there is a monotonic increase in this pressure with the filling of 4f shell.
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High pressure phase transitions in the rare earth metal erbium to 151 GPa
NASA Astrophysics Data System (ADS)
Samudrala, Gopi K.; Thomas, Sarah A.; Montgomery, Jeffrey M.; Vohra, Yogesh K.
2011-08-01
High pressure x-ray diffraction studies have been performed on the heavy rare earth metal erbium (Er) in a diamond anvil cell at room temperature to a pressure of 151 GPa and Er has been compressed to 40% of its initial volume. The rare earth crystal structure sequence {hcp} \\to {Sm}~ {type} \\to {dhcp} \\to {distorted} fcc (hcp: hexagonal close packed; fcc: face centered cubic; dhcp: double hcp) is observed in Er below 58 GPa. We have carried out Rietveld refinement of crystal structures in the pressure range between 58 GPa and 151 GPa. We have examined various crystal structures that have been proposed for the distorted fcc (dfcc) phase and the post-dfcc phase in rare earth metals. We find that the hexagonal hR 24 structure is the best fit between 58 and 118 GPa. Above 118 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of - 1.9%. We have also established a clear trend for the pressure at which a post-dfcc phase is formed in rare earth metals and show that there is a monotonic increase in this pressure with the filling of 4f shell.
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Thermodynamics of MgO shocked to 250 GPa and 9000 K
NASA Astrophysics Data System (ADS)
Fat'yanov, O. V.; Asimow, P. D.; Ahrens, T. J.
2011-06-01
Plate impact experiments in the 200-250 GPa pressure range were done on <100 > single-crystal MgO preheated before compression to 1850 K. Hot Mo(driver)-MgO targets were impacted with Ta flyers launched by the Caltech two-stage light-gas gun up to 7.5 km/s. Radiative temperatures and shock velocities were measured with 3-5% and 1-2% respective uncertainty by a 6-channel pyrometer with 3 ns time resolution, over 500-900 nm spectral range. MgO shock front reflectivity was determined in additional experiments at 220 and 250 GPa using 50/50 high-temperature sapphire beamsplitters. Shock temperatures and preheated MgO Hugoniot data reported here are in good agreement with the corresponding values calculated using Mie-Grüneisen equation of state with γ0 = 1.4 and constant γ / V . Our experiments showed no evidence of MgO melting up to 250 GPa and 9.2 kK. The highest shock temperatures exceed the extrapolated melting curve of Zerr & Boehler by >3000 K at 250 GPa, which seems too much for any realistic superheating.
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Sound velocities in shocked liquid D2 to 28 GPa
NASA Astrophysics Data System (ADS)
Holmes, N. C.; Ross, M.; Nellis, W. J.
1999-06-01
Recent measurements of shock temperatures(N. C. Holmes, W. J. Nellis, and M. Ross, Phys. Rev.) B52, 15835 (1995). and laser-driven Hugoniot measurements(L. B. Da Silva, et al.), Phys. Rev. Lett. 78, 483 (1997). of shocked liquid deuterium strongly indicate that molecular dissociation is important above 20 GPa. Since the amount of expected dissociation is small on the Hugoniot at the 30 GPa limit of conventional impact experiments, other methods must be used to test our understanding of the physics of highly compressed deuterium in this regime. We have recently performed experiments to measure the sound velocity of deuterium which test the isentropic compressibility, c^2 = (partial P/partial ρ)_S. We used the shock overtake method to measure sound velocities at several shock pressures between 10--28 GPa. These data provide support for recently developed molecular dissociation models.
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Pressure standards and sensors up to 3 GPa, actual state and development trends
NASA Astrophysics Data System (ADS)
Wisniewski, Roland; Molinar, Gianfranco
1999-04-01
Metrological problems connected with pressure standards and sensors up to 3 GPa as an introduction to the pressure measurements in the so-called “GIGAPASCAL REGION”, 1-100 GPa, are discussed. Re-examination of Bi I-Bi II phase transition pressure as a fixed point of the International Practical Pressure Scale and correction of the NaCl Pressure Scale is proposed. Well-established sensors as candidates for secondary pressure standards up to 3 GPa are briefly presented.
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Phase stability of iron germanate, FeGeO 3, to 127 GPa
Dutta, R.; Tracy, S. J.; Stan, C. V.; ...
2017-11-15
The high-pressure behavior of germanates is of interest as these compounds serve as analogs for silicates of the deep Earth. Current theoretical and experimental studies of iron germanate, FeGeO 3, are limited. Here in this paper, we have examined the behavior of FeGeO 3 to 127 GPa using the laser-heated diamond anvil cell combined with in situ synchrotron X-ray diffraction. Upon compression at room temperature, the ambient-pressure clinopyroxene phase transforms to a disordered triclinic phase [FeGeO 3 (II)] at ~ 18 GPa in agreement with earlier studies. An additional phase transition to FeGeO 3 (III) occurs above 54 GPa atmore » room temperature. Laser-heating experiments (~ 1200–2200 K) were conducted at three pressures (33, 54, and 123 GPa) chosen to cover the stability regions of different GeO 2 polymorphs. In all cases, we observe that FeGeO 3 dissociates into GeO 2 + FeO at high pressure and temperature conditions. Neither the perovskite nor the post-perovskite phase was observed up to 127 GPa at ambient or high temperatures. The results are consistent with the behavior of FeSiO 3, which also dissociates into a mixture of the oxides (FeO + SiO 2) at least up to 149 GPa.« less
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THE G.P.A. CRITERION AND SELECTIVE RETENTION IN TEACHER EDUCATION.
ERIC Educational Resources Information Center
PIERSON, ROBERT A.
TO DETERMINE WHETHER ARBITRARY GRADE-POINT AVERAGE CUT-OFF POINTS (E.G. 2.25) FOR ENTRANCE INTO TEACHER EDUCATION PROGRAMS ARE UNFAIR TO PRESENT-DAY STUDENTS, NINETY 1966 COLLEGE SOPHOMORES WITH FRESHMAN-YEAR GPA'S BETWEEN 2.00 AND 2.09 WERE COMPARED TO THE SAME NUMBER OF 1961 SOPHOMORES WITH FRESHMAN-YEAR GPA'S BETWEEN 2.25 AND 2.34 USING (1)…
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GPA as a Predictor of Helpful Behavior: An Accounting Student Sample
ERIC Educational Resources Information Center
Lyons, Paul; Bandura, Randall P.
2017-01-01
Purpose: The purpose of this paper is to demonstrate the value of student grade point average (GPA) as a predictor of pro-social, helpful behavior. This voluntary behavior has been shown to be highly valuable to managers and co-workers. GPA is not only predictive of success in core tasks on the job, it is also predictive of voluntary, helpful…
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X-ray Diffraction Study of Aluminum Carbide Powder to 50 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ji, C.; Ma, Y; Chyu, M
2009-01-01
The crystal structure and equation of state (EOS) of aluminum carbide (Al{sub 4}C{sub 3}) have been determined directly up to 50.1 GPa at room temperature by the synchrotron x-ray diffraction techniques. The results indicate that Al{sub 4}C{sub 3} remained in rhombohedral structure under all tested pressure-temperature conditions and exhibited anisotropic compressibility, with the c-axis more compressible than the a-axis. Fitting the experimental data to third order Birch-Murnaghan EOS yields a bulk modulus of K{sub OT} = 233 {+-} 6 GPa with its pressure derivative K{sub OT}{prime} = 3.4 {+-} 0.4, while the second-order EOS yields K{sub OT} = 223 {+-}more » 2 GPa.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Leinenweber, Kurt, E-mail: kurtl@asu.edu; Gullikson, Amber L.; Stoyanov, Emil
2015-09-15
The accuracy and precision of pressure measurements and the pursuit of reliable and readily available pressure scales at simultaneous high temperatures and pressures are still topics in development in high pressure research despite many years of work. In situ pressure scales based on x-ray diffraction are widely used but require x-ray access, which is lacking outside of x-ray beam lines. Other methods such as fixed points require several experiments to bracket a pressure calibration point. In this study, a recoverable high-temperature pressure gauge for pressures ranging from 3 GPa to 10 GPa is presented. The gauge is based on themore » pressure-dependent solubility of an SiO{sub 2} component in the rutile-structured phase of GeO{sub 2} (argutite), and is valid when the argutite solid solution coexists with coesite. The solid solution varies strongly in composition, mainly in pressure but also somewhat in temperature, and the compositional variations are easily detected by x-ray diffraction of the recovered products because of significant changes in the lattice parameters. The solid solution is measured here on two isotherms, one at 1200 °C and the other at 1500 °C, and is developed as a pressure gauge by calibrating it against three fixed points for each temperature and against the lattice parameter of MgO measured in situ at a total of three additional points. A somewhat detailed thermodynamic analysis is then presented that allows the pressure gauge to be used at other temperatures. This provides a way to accurately and reproducibly evaluate the pressure in high pressure experiments and applications in this pressure-temperature range, and could potentially be used as a benchmark to compare various other pressure scales under high temperature conditions. - Graphical abstract: The saturation curve of SiO{sub 2} in TiO{sub 2} shows a strong pressure dependence and a strong dependence of unit cell volume on composition. This provides an opportunity to use this
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Thermodynamics and Equations of State of Iron to 350 GPa and 6000 K
NASA Astrophysics Data System (ADS)
Dorogokupets, P. I.; Dymshits, A. M.; Litasov, K. D.; Sokolova, T. S.
2017-03-01
The equations of state for solid (with bcc, fcc, and hcp structures) and liquid phases of Fe were defined via simultaneous optimization of the heat capacity, bulk moduli, thermal expansion, and volume at room and higher temperatures. The calculated triple points at the phase diagram have the following parameters: bcc-fcc-hcp is located at 7.3 GPa and 820 K, bcc-fcc-liquid at 5.2 GPa and 1998 K, and fcc-hcp-liquid at 106.5 GPa and 3787 K. At conditions near the fcc-hcp-liquid triple point, the Clapeyron slope of the fcc-liquid curve is dT/dP = 12.8 K/GPa while the slope of the hcp-liquid curve is higher (dT/dP = 13.7 K/GPa). Therefore, the hcp-liquid curve overlaps the metastable fcc-liquid curve at pressures of about 160 GPa. At high-pressure conditions, the metastable bcc-hcp curve is located inside the fcc-Fe or liquid stability field. The density, adiabatic bulk modulus and P-wave velocity of liquid Fe calculated up to 328.9 GPa at adiabatic temperature conditions started from 5882 K (outer/inner core boundary) were compared to the PREM seismological model. We determined the density deficit of hcp-Fe at the inner core boundary (T = 5882 K and P = 328.9 GPa) to be 4.4%.
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Thermodynamics and Equations of State of Iron to 350 GPa and 6000 K.
Dorogokupets, P I; Dymshits, A M; Litasov, K D; Sokolova, T S
2017-03-06
The equations of state for solid (with bcc, fcc, and hcp structures) and liquid phases of Fe were defined via simultaneous optimization of the heat capacity, bulk moduli, thermal expansion, and volume at room and higher temperatures. The calculated triple points at the phase diagram have the following parameters: bcc-fcc-hcp is located at 7.3 GPa and 820 K, bcc-fcc-liquid at 5.2 GPa and 1998 K, and fcc-hcp-liquid at 106.5 GPa and 3787 K. At conditions near the fcc-hcp-liquid triple point, the Clapeyron slope of the fcc-liquid curve is dT/dP = 12.8 K/GPa while the slope of the hcp-liquid curve is higher (dT/dP = 13.7 K/GPa). Therefore, the hcp-liquid curve overlaps the metastable fcc-liquid curve at pressures of about 160 GPa. At high-pressure conditions, the metastable bcc-hcp curve is located inside the fcc-Fe or liquid stability field. The density, adiabatic bulk modulus and P-wave velocity of liquid Fe calculated up to 328.9 GPa at adiabatic temperature conditions started from 5882 K (outer/inner core boundary) were compared to the PREM seismological model. We determined the density deficit of hcp-Fe at the inner core boundary (T = 5882 K and P = 328.9 GPa) to be 4.4%.
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Thermodynamics and Equations of State of Iron to 350 GPa and 6000 K
Dorogokupets, P. I.; Dymshits, A. M.; Litasov, K. D.; Sokolova, T. S.
2017-01-01
The equations of state for solid (with bcc, fcc, and hcp structures) and liquid phases of Fe were defined via simultaneous optimization of the heat capacity, bulk moduli, thermal expansion, and volume at room and higher temperatures. The calculated triple points at the phase diagram have the following parameters: bcc–fcc–hcp is located at 7.3 GPa and 820 K, bcc–fcc–liquid at 5.2 GPa and 1998 K, and fcc–hcp–liquid at 106.5 GPa and 3787 K. At conditions near the fcc–hcp–liquid triple point, the Clapeyron slope of the fcc–liquid curve is dT/dP = 12.8 K/GPa while the slope of the hcp–liquid curve is higher (dT/dP = 13.7 K/GPa). Therefore, the hcp–liquid curve overlaps the metastable fcc–liquid curve at pressures of about 160 GPa. At high-pressure conditions, the metastable bcc–hcp curve is located inside the fcc-Fe or liquid stability field. The density, adiabatic bulk modulus and P-wave velocity of liquid Fe calculated up to 328.9 GPa at adiabatic temperature conditions started from 5882 K (outer/inner core boundary) were compared to the PREM seismological model. We determined the density deficit of hcp-Fe at the inner core boundary (T = 5882 K and P = 328.9 GPa) to be 4.4%. PMID:28262683
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AC calorimetry of H2O at pressures up to 9 GPa in diamond anvil cells
NASA Astrophysics Data System (ADS)
Geballe, Zachary M.; Struzhkin, Viktor V.
2017-06-01
If successfully developed, calorimetry at tens of GPa of pressure could help characterize phase transitions in materials such as high-pressure minerals, metals, and molecular solids. Here, we extend alternating-current calorimetry to 9 GPa and 300 K in a diamond anvil cell and use it to study phase transitions in H2O. In particular, water is loaded into the sample chambers of diamond-cells, along with thin metal heaters (1 μm-thick platinum or 20 nm-thick gold on a glass substrate) that drive high-frequency temperature oscillations (20 Hz to 600 kHz; 1 to 10 K). The heaters also act as thermometers via the third-harmonic technique, yielding calorimetric data on (1) heat conduction to the diamonds and (2) heat transport into substrate and sample. Using this method during temperature cycles from 300 to 200 K, we document melting, freezing, and proton ordering and disordering transitions of H2O at 0 to 9 GPa, and characterize changes in thermal conductivity and heat capacity across these transitions. The technique and analysis pave the way for calorimetry experiments on any non-metal at pressures up to ˜100 GPa, provided a thin layer (several μm-thick) of thermal insulation supports a metallic thin-film (tens of nm thick) Joule-heater attached to low contact resistance leads inside the sample chamber of a diamond-cell.
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Static high-pressure structural studies on Dy to 119 GPa
NASA Astrophysics Data System (ADS)
Patterson, Reed; Saw, Cheng K.; Akella, Jagannadham
2004-05-01
Structural phase transitions in the rare-earth metal dysprosium have been studied in a diamond anvil cell to 119 GPa by x-ray diffraction. Four transformations following the sequence hcp→Sm-type→dhcp→hR24 (hexagonal)→bcm (monoclinic) are observed at 6, 15, 43, and 73 GPa, respectively. The hexagonal to monoclinic transformation is accompanied by a 6% reduction in volume, which is attributed to delocalization of the 4f electrons, similar to that seen in Ce, Pr, and Gd.
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48 CFR 25.504-2 - WTO GPA/Caribbean Basin Trade Initiative/FTAs.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false WTO GPA/Caribbean Basin Trade Initiative/FTAs. 25.504-2 Section 25.504-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Evaluating Foreign Offers-Supply Contracts 25.504-2 WTO GPA/Caribbean Basin Trade...
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48 CFR 25.504-2 - WTO GPA/Caribbean Basin Trade Initiative/FTAs.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false WTO GPA/Caribbean Basin Trade Initiative/FTAs. 25.504-2 Section 25.504-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Evaluating Foreign Offers-Supply Contracts 25.504-2 WTO GPA/Caribbean Basin Trade...
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48 CFR 25.504-2 - WTO GPA/Caribbean Basin Trade Initiative/FTAs.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false WTO GPA/Caribbean Basin Trade Initiative/FTAs. 25.504-2 Section 25.504-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Evaluating Foreign Offers-Supply Contracts 25.504-2 WTO GPA/Caribbean Basin Trade...
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48 CFR 25.504-2 - WTO GPA/Caribbean Basin Trade Initiative/FTAs.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false WTO GPA/Caribbean Basin Trade Initiative/FTAs. 25.504-2 Section 25.504-2 Federal Acquisition Regulations System FEDERAL... 25.504-2 WTO GPA/Caribbean Basin Trade Initiative/FTAs. Example 1. Offer A 304,000 U.S.-made end...
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48 CFR 25.504-2 - WTO GPA/Caribbean Basin Trade Initiative/FTAs.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false WTO GPA/Caribbean Basin Trade Initiative/FTAs. 25.504-2 Section 25.504-2 Federal Acquisition Regulations System FEDERAL... 25.504-2 WTO GPA/Caribbean Basin Trade Initiative/FTAs. Example 1. Offer A 304,000 U.S.-made end...
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Static High Pressure Structural studies on Dy to 119 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Patterson, J R; Saw, C K; Akella, J
2003-11-12
Structural phase transitions in the rare-earth metal Dysprosium have been studied in a Diamond Anvil Cell (DAC) to 119 GPa by x-ray diffraction. Four transformations following the sequence hcp {yields} Sm-type {yields} dhcp {yields} hR24 (hexagonal) {yields} bcm (monoclinic) are observed at 6, 15, 43, and 73 GPa respectively. The hexagonal to monoclinic transformation is accompanied by a 6% reduction in volume, which is attributed to delocalization of the 4f electrons, similar to that seen in Ce, Pr, and Gd.
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Microscopic structural change in a liquid Fe-C alloy of ~5 GPa
Shibazaki, Yuki; Kono, Yoshio; Fei, Yingwei
2015-07-04
The structure of a liquid Fe-3.5 wt% C alloy is examined for up to 7.2 GPa via multiangle energy-dispersive X-ray diffraction using a Paris-Edinburgh type large-volume press. X-ray diffraction data show clear changes in the pressure-dependent peak positions of structure factor and reduced pair distribution function at 5GPa. These results suggest that the liquid Fe-3.5wt%C alloys change structurally at approximately 5GPa. This finding serves as a microscopic explanation for the alloy’s previously observed density change at the same pressure. The pressure dependencies of the nearest and second neighbor distances of the liquid Fe-3.5 wt% C alloy are similar to thosemore » of liquid Fe which exhibits a structural change near the bcc-fcc-liquid triple point (5.2GPa and 1991 K). Here, similarities between Fe-3.5wt% C and Fe suggest that a density change also occurs in liquid Fe and that this structural change extends to other Fe-light element alloys.« less
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Strength of fayalite up to 8.5 GPa
NASA Astrophysics Data System (ADS)
Guignard, J.; Bystricky, M.; Béjina, F.; Crichton, W. A.; Proietti, A.; Tercé, N.
2017-06-01
A dense polycrystalline aggregate of synthetic fayalite (Fe2SiO4) was deformed up to 8.5 GPa at room temperature in the D-DIA press installed at the European Synchrotron Radiation Facility beamline ID06. Five successive shortening-lengthening cycles were performed at different pressures and up to a final strain of approximately 25% at a typical strain rate of about 10-5 s-1. Lattice stresses were quantified from ( hkl) reflections accessible with a 55-keV monochromatic beam. Combined stress and strain data show that during each cycle, fayalite deforms elastically before yielding at an axial strain close to 2%. This yielding occurs at a macroscopic stress (taken as the average of the estimated lattice stresses) of 1.5-2 GPa, irrespective of pressure. Very moderate stress hardening takes place beyond the yield point, and the average stress becomes almost constant after a strain of 5-6%, suggesting a low-temperature plastic regime. Lattice stresses estimated with (131), (130), and (022) reflections are always higher than stresses estimated with (111) and (112) by a factor of about 1.5. In addition, the (131) lattice stress becomes progressively lower than the (130) and (022) lattice stresses with increasing pressure, which suggests a possible change in dominant slip systems around 5-6 GPa. Combining our results with data from Chen et al. (Phys Earth Planet Inter 143-144:347-356, (2004), we determined a low-temperature plasticity flow law with an activation energy of 217 ± 25 kJ mol-1 and a Peierls stress at 0 GPa, σ p0 = 3.92 ± 0.02 GPa, that is consistent with dislocation motion being limited by discrete obstacles. The pressure dependence is almost entirely accounted for by the Peierls stress, with d σ p/d P = G'/ G 0, where G' is the derivative of G 0, the shear modulus. Our results suggest that fayalite has a smaller pressure dependence of low-temperature plasticity than (Mg0.9Fe0.1)2SiO4 and that the transition between low-temperature plasticity and high
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High pressure melting curve of platinum up to 35 GPa
NASA Astrophysics Data System (ADS)
Patel, Nishant N.; Sunder, Meenakshi
2018-04-01
Melting curve of Platinum (Pt) has been measured up to 35 GPa using our laboratory based laser heated diamond anvil cell (LHDAC) facility. Laser speckle method has been employed to detect onset of melting. High pressure melting curve of Pt obtained in the present study has been compared with previously reported experimental and theoretical results. The melting curve measured agrees well within experimental error with the results of Kavner et al. The experimental data fitted with simon equation gives (∂Tm/∂P) ˜25 K/GPa at P˜1 MPa.
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Single-Crystal X-Ray Diffraction of Pyrope Garnet to 84 GPa
NASA Astrophysics Data System (ADS)
Finkelstein, G. J.; Dera, P. K.; Duffy, T. S.
2012-12-01
Garnets are characteristic minerals of many metamorphic and igneous rocks, and are also important upper-mantle constituents. Mg-rich (pyrope) garnets occur in both peridotite and eclogite compositions in the upper mantle. At high temperatures and pressures above 25 GPa, garnets transform to the perovskite structure. The post-garnet transition kinetics are sluggish, and in cold subducting slabs garnets could persist metastably at temperatures as high as 1700 K on geological timescales. These phases could add positive buoyancy to a subducting slab, inhibiting subduction. There has been minimal previous work on the 300 K compression behavior of aluminosilicate garnets at pressures higher than 10 GPa. In this work, we have collected single-crystal X-ray diffraction data on near end-member natural pyrope (Dora Maira pyrope) to 84 GPa. By extending the compression of pyrope to much higher pressures, we can better constrain the equation of state while also characterizing the structural response to such extreme pressures for the first time. Crystals were polished to ~5-10 μm in thickness, and loaded in a diamond anvil cell with gold foil and ruby balls as pressure calibrants. Helium was used as a pressure-transmitting medium. High-pressure single-crystal X-ray diffraction experiments were performed at the GSECARS 13-ID-D beamline of the Advanced Photon Source and the 12.2.2 beamline of the Advanced Light Source. Structure refinements were carried out successfully to the highest pressure using Shelx-97, extending the range over which the compression behavior of this material has been characterized by a factor of nearly three. Pyrope exhibits smooth compression behavior and no phase transitions over the investigated pressure range. A preliminary 3rd order Birch-Murnaghan equation of state was successfully fit to data up to 52 GPa. If the bulk modulus is fixed to 170 GPa, a value consistent with previous Brillouin and Ultrasonic studies, our data yields a pressure derivative
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Phase transformations and equation of state of praseodymium metal to 103 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chesnut, Gary N.; Vohra, Yogesh K.
2000-08-01
Pressure-induced structural phase transformations in a trivalent rare-earth metal praseodymium (Pr) were studied at room temperature in a diamond anvil cell to 103 GPa by energy dispersive x-ray diffraction using a synchrotron source. Our x-ray diffraction studies document the following crystal structure sequence: dhcp{yields}fcc{yields}distorted fcc(hR24 type){yields}monoclinic(C2/m){yields}{alpha}-uranium with increasing pressure. We measure a 16.7% volume collapse at the transition to the {alpha}-uranium phase at 20 GPa. The high-pressure {alpha}-uranium phase in Pr was found to be stable to the highest pressure of 103 GPa, which corresponds to a volume compression V/V{sub 0}=0.407. (c) 2000 The American Physical Society.
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Bakker, E; Butterbach, P; Rouppe van der Voort, J; van der Vossen, E; van Vliet, J; Bakker, J; Goverse, A
2003-05-01
Nine resistance gene homologues (RGHs) were identified in two diploid potato clones (SH and RH), with a specific primer pair based on conserved motifs in the LRR domain of the potato cyst nematode resistance gene Gpa2 and the potato virus X resistance gene Rx1. A modified AFLP method was used to facilitate the genetic mapping of the RGHs in the four haplotypes under investigation. All nine RGHs appeared to be located in the Gpa2/ Rx1 cluster on chromosome XII. Construction of a physical map using bacterial artificial chromosome (BAC) clones for both the Solanum tuberosum ssp. tuberosum and the S. tuberosum ssp. andigena haplotype of SH showed that the RGHs are located within a stretch of less than 200 kb. Sequence analysis of the RGHs revealed that they are highly similar (93 to 95%) to Gpa2 and Rx1. The sequence identities among all RGHs range from 85 to 100%. Two pairs of RGHs are identical, or nearly so (100 and 99.9%), with each member located in a different genotype. Southern-blot analysis on genomic DNA revealed no evidence for additional homologues outside the Gpa2/ Rx1 cluster on chromosome XII.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Mochalov, M. A., E-mail: postmaster@ifv.vniief.ru; Il'kaev, R. I.; Fortov, V. E.
2012-10-15
The quasi-isentropic compressibility of helium and deuterium plasmas at pressures of up to 1500-2000 GPa has been measured using devices with spherical geometry and an X-ray diagnostic complex comprising three betatrons and a multichannel imaging system with electro-optic gamma detectors. A deuterium density of 4.5 g/cm{sup 3} and a helium density of 3.8 g/cm{sup 3} have been obtained at pressures of 2210 and 1580 GPa, respectively. The internal energy of a deuterium plasma at the indicated pressure is about 1 MJ/cm{sup 3}, which is about 100 times greater than the specific energy of condensed chemical explosives. Analysis of the obtainedmore » data shows that the degree of helium ionization under the achieved plasma compression parameters is about 0.9.« less
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Gas metal arc weldability of 1.5 GPa grade martensitic steels
NASA Astrophysics Data System (ADS)
Hwang, Insung; Yun, Hyeonsang; Kim, Dongcheol; Kang, Munjin; Kim, Young-Min
2018-01-01
The gas metal arc weldability of 1.5 GPa grade martensitic (MART) steel was evaluated using both inverter direct current (DC) and DC pulse power type welders, under conditions of different welding currents, welding speeds, and shielding gasses. By investigating the bead appearance, tensile strength, and arc stability, it was determined that DC pulse power is better than inverter DC power for arc welding of 1.3 mm thick 1.5 GPa grade MART steel. Further, from the results of the weldability for various shielding gases, it was determined that mixed shielding gas is more effective for welding 1.5 GPa grade MART steel than is pure inert gas (Ar) or active (CO2) gas. In the case of pure shielding gas, no sound bead was formed under any conditions. However, when the mixed shielding gas was used, sound and fine beads were obtained.
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NASA Astrophysics Data System (ADS)
Neel, Christopher; Lacina, David; Johnson, Stephanie
2017-01-01
Plate impact experiments were conducted on a cold-sprayed Al-CuO thermite at peak stresses between 5-35 GPa to determine the Hugoniot curve and characterize any shock induced energetic reaction. Photon Doppler Velocimetry (PDV) measurements were used to obtain particle velocity histories and shock speed information for both the shock loading and unloading behavior of the material. A jump in shock velocity was observed in the Hugoniot curve when the material was shocked beyond 20 GPa, suggesting a volume-increasing reaction occurs in this shocked Al-CuO thermite near 20 GPa. To better characterize any shock-induced thermite reactions, emission spectroscopy measurements were obtained at stresses above 20 GPa. The best time-resolved spectra obtained thus far, at 25 GPa, does not support the fast thermite reaction hypothesis.
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Stability of Carbonated Eclogite in the Upper Mantle: Experimental Solidus from 2 to 9 GPa
NASA Astrophysics Data System (ADS)
Dasgupta, R.; Withers, A. C.; Hirschmann, M. M.
2003-12-01
Carbonates are pervasive alteration products of the oceanic crust and likely survive subduction-related dehydration and/or melting. Thus, significant quantities of carbonated refractory eclogite are probably delivered to the deeper mantle. The melting behavior of such recycled carbonate influences the fate of recycled carbon, determines the possible sources and depths of carbonated metasomatic melts in the mantle, and delimits the conditions under which carbonated eclogite may act as a source of carbonatite and other types of magmatic CO2. We present partial melting experiments of carbonated eclogite that constrain the solidus and near solidus phase relations from 2 to 9 GPa. To simulate the near-isochemical nature of ocean floor carbonation, the starting material was prepared by adding 5 wt.% CO2 in the form of a mixture of Fe-Mg-Ca-Na-K carbonates to a bimineralic eclogite from Salt Lake crater, Oahu, Hawaii. The starting composition is a reasonable approximation of carbonated oceanic crust from which siliceous hydrous fluid has been extracted by subduction. We find that melt-present versus melt-absent conditions can be distinguished based on textural criteria. Garnet and cpx appear in all the experiments. Between 2 and 3 GPa, the subsolidus assemblage also includes calcite-dolomitess + ilmenite, whereas above the solidus (950-975 ° C at 2 GPa and 1050-1075 ° C at 3 GPa) calcio-dolomitic liquid appears. From 3 to 4.5 GPa, dolomitess becomes stable at the solidus and the near solidus melt becomes increasingly dolomitic. Appearance of dolomite above 3 GPa is accompanied by a negative Clapeyron slope of the solidus, with the cusp located between 995 and 1025 ° C at ca. 4 GPa. Above 4-4.5 GPa, the solidus again rises with increasing pressure to ca. 1245 ° C at 9 GPa and magnesite becomes the subsolidus carbonate. Dolomitic melt coexists with magnesite + garnet + cpx + rutile between 5 and 9 GPa. If extrapolated to higher pressures, the carbonated eclogite solidus
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Metatarsal Shape and Foot Type: A Geometric Morphometric Analysis.
Telfer, Scott; Kindig, Matthew W; Sangeorzan, Bruce J; Ledoux, William R
2017-03-01
Planus and cavus foot types have been associated with an increased risk of pain and disability. Improving our understanding of the geometric differences between bones in different foot types may provide insights into injury risk profiles and have implications for the design of musculoskeletal and finite-element models. In this study, we performed a geometric morphometric analysis on the geometry of metatarsal bones from 65 feet, segmented from computed tomography (CT) scans. These were categorized into four foot types: pes cavus, neutrally aligned, asymptomatic pes planus, and symptomatic pes planus. Generalized procrustes analysis (GPA) followed by permutation tests was used to determine significant shape differences associated with foot type and sex, and principal component analysis was used to find the modes of variation for each metatarsal. Significant shape differences were found between foot types for all the metatarsals (p < 0.01), most notably in the case of the second metatarsal which showed significant pairwise differences across all the foot types. Analysis of the principal components of variation showed pes cavus bones to have reduced cross-sectional areas in the sagittal and frontal planes. The first (p = 0.02) and fourth metatarsals (p = 0.003) were found to have significant sex-based differences, with first metatarsals from females shown to have reduced width, and fourth metatarsals from females shown to have reduced frontal and sagittal plane cross-sectional areas. Overall, these findings suggest that metatarsal bones have distinct morphological characteristics that are associated with foot type and sex, with implications for our understanding of anatomy and numerical modeling of the foot.
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NASA Astrophysics Data System (ADS)
Meier, Thomas; Khandarkhaeva, Saiana; Petitgirard, Sylvain; Körber, Thomas; Lauerer, Alexander; Rössler, Ernst; Dubrovinsky, Leonid
2018-07-01
The past 15 years have seen an astonishing increase in Nuclear Magnetic Resonance (NMR) sensitivity and accessible pressure range in high-pressure NMR experiments, owing to a series of new developments of NMR spectroscopy applied to the diamond anvil cell (DAC). Recently, with the application of electro-magnetic lenses, so-called Lenz lenses, in toroidal diamond indenter cells, pressures of up to 72 GPa with NMR spin sensitivities of about 1012 spin/Hz1/2 has been achieved. Here, we describe the implementation of a refined NMR resonator structure using a pair of double stage Lenz lenses driven by a Helmholtz coil within a standard DAC, allowing to measure sample volumes as small as 100 pl prior to compression. With this set-up, pressures close to 100 GPa could be realised repeatedly, with enhanced spin sensitivities of about 5 × 1011 spin/Hz1/2. The manufacturing and handling of these new NMR-DACs is relatively easy and straightforward, which will allow for further applications in physics, chemistry, or biochemistry.
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The Role of First-Semester GPA in Predicting Graduation Rates of Underrepresented Students
ERIC Educational Resources Information Center
Gershenfeld, Susan; Hood, Denice Ward; Zhan, Min
2016-01-01
Academic performance is a primary predictor of college graduation, yet few studies have examined one of the earliest indicators of academic performance--first-semester grade point average (GPA). Given the considerable public and private investment in ensuring access for underrepresented students, a focus on the role of first-semester GPA for these…
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NASA Astrophysics Data System (ADS)
Green, H. W.; Dobrzhinetskaya, L. F.
2004-12-01
Evidence is now robust that continental rocks and sediments can be subducted to P > 6 GPa during continental collision and returned to the surface. Moreover, mantle rocks exhumed with this subducted material carry evidence of P > 9 GPa and perhaps much more. We present a short review of natural examples and discuss them in the context of decompression experiments conducted on garnet lherzolite over the range 14 -> 5 GPa. Experiments at 14 GPa dissolved all enstatite (En) and about 85% diopside (Di) into garnet, yielding run products of 40% Ol + 55% Grt + 5% Di. Re-annealing this product at 13 or 12 GPa resulted in exsolution of Di as blebs at garnet grain boundaries and oriented platelets of Ol chemistry within grt. Specimens first equilibrated at 8 GPa dissolved abundant En but little Di. When re-annealed at 5 GPa, En exsolved as blebs at garnet boundaries -- very similar to interstitial blebs of enstatite along grt grain boundaries in UHP (>200 km) Norwegian grt-harzburgite. In the latter rocks, abundant En and rare Di exsolution lamellae are also found in the cores of large garnets. Our experiments do not show such lamellae, supporting the arguments of van Roermund and Drury (1998) that they are produced only in the cores of large grains and that the interstitial pyroxenes found in their specimens are also exsolution products. Ol has not been reported with exsolution morphology in natural UHP products, nor did we observe it in our experiments at P = 5 GPa. On the other hand, our observation that Ol may be exsolved during decompression of majoritic garnet during decompression at higher P is consistent with expansion of the garnet field at the expense of wadsleyite at P > 13 GPa reported by Ringwood (1991). Di, En, and/or Ol do occur along grain boundaries within larger polycrystalline garnets and within embayments at the margins of smaller amoeboid garnets in subduction zone garnet peridotites. Such garnets also may contain rounded, non-oriented, inclusions of
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GPA and Attribute Framing Effects: Are Better Students More Sensitive or More Susceptible?
ERIC Educational Resources Information Center
Dunegan, Ken
2010-01-01
Data from 2 studies show students differ in terms of how attribute framing alters perceptions and reactions in a decision-making episode. Using student GPA as a moderator, results from a role-play-decision-making exercise (Experiment 1) show perceptions and intended actions of higher GPA students were more strongly affected by attribute framing…
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Water solubility of synthetic pyrope at high temperature and pressure up to 12GPa
NASA Astrophysics Data System (ADS)
Huang, S.; Chen, J.
2012-12-01
Water can be incorporated into normally anhydrous minerals as OH- defects and transported into the mantle. Its existence in the mantle may affect property of minerals, such as elasticity, electrical conductivity and rheological properties. As the secondary mineral in the mantle, garnet has not been extensively studied for its water solubility and there is discrepancies among the existing experiments on the water solubility in the garnet change at pressures and temperatures. Geiger et al., 1991 investigated water content in synthetic pyrope and concluded 0.02wt% to 0.07wt% OH- substitution. Lu et al., 1997 found 198ppm water in the Dora Miara pyrope at 100Kbar and 1000°C. Withers et al., 1998 claimed that water solubility in pyrope reached 1000ppm at 5GPa and then decreased as pressure increasing; above 7GPa, no water was detected. Mookherjee et al., 2009 also explored pyrope-rich garnet, which contains water up to 0.1%wt at 5-9GPa and temperatures 1373K-1473K. Here we report a study of water solubility of synthetic single crystal pyrope at pressures 4-12GPa and temperature 1000°C. Single crystals of pyrope were synthesized using multi-anvil press and water contents in these samples were measured using FTIR. We have observed OH- peak at 3650 cm-1 along this pressure range, although Withers, 1998 reported water contents decrease to undetectable level above 7GPa. Water solubility in pyrope will be reported as a function of pressure up to 12 GPa at 1000°C.
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Determinants of Undergraduate GPAs: SAT Scores, High-School GPA and High-School Rank
ERIC Educational Resources Information Center
Cohn, Elchanan; Cohn, Sharon; Balch, Donald C.; Bradley, James, Jr.
2004-01-01
The primary purpose of the study is to assess the degree to which SAT scores, high-school GPA (HSGPA) and class rank predict success in college. Data collected from students enrolled in several sections of Principles of Economics at the University of South Carolina in 2000 and 2001 are used to study the relation between college GPA (the dependent…
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Strike Four! Do-Over Policies Institutionalize GPA Distortion
ERIC Educational Resources Information Center
Marx, Jonathan; Meeler, David
2013-01-01
Purpose: The aim of this paper is to illustrate how universities play an institutional role in inflating student grade point averages (GPA) by modifying academic polices such as course withdraw, repeats, and satisfactory/unsatisfactory grade options. Design/methodology/approach: Three research strategies are employed: an examination of eight…
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GPA/GPSA/OSU-Okmulgee natural gas compression technician training program
DOE Office of Scientific and Technical Information (OSTI.GOV)
Doede, S.
Approximately one year ago, OSU-Okmulgee and the Gas Processors Association began discussions about the possibility of developing a natural Gas Technician Training Program for GPA members. Following a presentation to the Membership and Services Committee, Chairman John Ehlers solicited and obtained the approval of the GPA Executive Committee to sponsor the program. Participation in the program was also made available to GPSA members. The purpose of the program is to upgrade the technical competency and professional level of incoming natural gas compression technicians. It educates students to analytically diagnose, service and maintain gas compression equipment and systems using industry recommendedmore » procedures, special tools and service information. It also provides course content, which will enable successful graduates to advance in position after additional experience, and to understand new systems, technologies and components as they are introduced. The two-year Associate-In-Applied Science Degree program includes six successive college semesters. Nearly one-half of the time is designated for technical/academic education at Oklahoma State University-Okmulgee with the balance of time allocated for on-the-job internship experiences at sponsoring GPA/GPSA members. Each block of technical education and general education course work is followed by an immediate work experience time period designated to reinforce the technical and general education. These time periods are approximately seven and one-half weeks in length each. It is essential for the success of the students and the program that the students' education at OSU-Okmulgee and work experiences at GPA/GPSA member facilities be closely aligned for maximum student learning and retention. In addition to technical classes on gas compression equipment and components, the courses offered in math, speech, technical writing, psychology and ethics for example, prepare students to be able to communicate well
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Nanobubbles at GPa Pressure under Graphene.
Zamborlini, Giovanni; Imam, Mighfar; Patera, Laerte L; Menteş, Tevfik Onur; Stojić, Nataša; Africh, Cristina; Sala, Alessandro; Binggeli, Nadia; Comelli, Giovanni; Locatelli, Andrea
2015-09-09
We provide direct evidence that irradiation of a graphene membrane on Ir with low-energy Ar ions induces formation of solid noble-gas nanobubbles. Their size can be controlled by thermal treatment, reaching tens of nanometers laterally and height of 1.5 nm upon annealing at 1080 °C. Ab initio calculations show that Ar nanobubbles are subject to pressures reaching tens of GPa, their formation being driven by minimization of the energy cost of film distortion and loss of adhesion.
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Dynamics anomaly in high-density amorphous ice between 0.7 and 1.1 GPa
NASA Astrophysics Data System (ADS)
Handle, Philip H.; Loerting, Thomas
2016-02-01
We studied high-density amorphous ices between 0.004 and 1.6 GPa by isobaric in situ volumetry and by subsequent ex situ x-ray diffraction and differential scanning calorimetry at 1 bar. Our observations indicate two processes, namely, relaxation in the amorphous matrix and crystallization, taking place at well-separated time scales. For this reason, we are able to report rate constants of crystallization kX and glass-transition temperatures Tg in an unprecedented pressure range. Tg's agree within ±3 K with earlier work in the small pressure range where there is overlap. Both Tg and kX show a pressure anomaly between 0.7 and 1.1 GPa, namely, a kX minimum and a Tg maximum. This anomalous pressure dependence suggests a continuous phase transition from high- (HDA) to very-high-density amorphous ice (VHDA) and faster hydrogen bond dynamics in VHDA. We speculate this phenomenology can be rationalized by invoking the crossing of a Widom line between 0.7 and 1.1 GPa emanating from a low-lying HDA-VHDA critical point. Furthermore, we interpret the volumetric relaxation of the amorphous matrix to be accompanied by viscosity change to explain the findings such that the liquid state can be accessed prior to the crystallization temperature TX at <0.4 GPa and >0.8 GPa.
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Mayall, Peter; Pilbrow, Varsha
2018-05-01
The arrival of the Huns into Europe in the fourth century AD increased the occurrence of intentional cranial modification among European nomads. It has been postulated that the Huns used a two-bandage cranial binding technique to differentiate themselves from surrounding nomadic groups, including those from Georgia. This study examines this hypothesis by comparing Migration Period (4th to 7th century AD) juvenile crania, which retain strong impressions of bindings, with adult modified crania from Hungary and Georgia. Twelve surface landmarks and 251 semi-landmarks were used to study ontogenetic trajectories in 9 juvenile and 16 adult modified skulls from 8 Hungarian sites and 21 adult skulls from two Georgian sites. Generalized Procrustes analysis, linear regression of Procrutes distance on dental age and log centroid size, and warping the principal components (PCs) in shape space helped to identify cranial shape changes. The PCs provide significant separation of the juvenile and adult groups from Georgia and Hungary. Variation in modified cranial shape was limited in Hungary compared to Georgia. There was stronger correlation between juvenile and adult modified cranial shape in Hungary than in Georgia. Warping along the first axis reveals the trajectory from marked flattening of the frontal and occipital regions in juveniles to diminished flattening in the same regions in adult crania, corresponding with one binding. Another depression extending from the post-bregmatic region to the temporal region, similarly strong in juveniles but diminishing in adults, marks the second binding. Hungarian crania were modified with two bindings with limited shape variation, whereas the Georgian crania had greater variation in shape being also modified with antero-posterior bindings. The findings from this study alongside contemporary historical sources help to understand the role of intentional cranial modification as a mark of social identity among nomads in the Migration Period
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X-ray diffraction of molybdenum under shock compression to 450 GPa
Wang, Jue; Coppari, Federica; Smith, Raymond F.; ...
2015-11-20
Molybdenum (Mo) is a body-centered-cubic (bcc) transition metal that has widespread technological applications. Although the bcc transition elements are used as test cases for understanding the behavior of metals under extreme conditions, the melting curves and phase transitions of these elements have been the subject of stark disagreements in recent years. Here we use x-ray diffraction to examine the phase stability and melting behavior of Mo under shock loading to 450 GPa. The bcc phase of Mo remains stable along the Hugoniot until 380 GPa. Here, our results do not support previous claims of a shallow melting curve for molybdenum.
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Beryl-II, a high-pressure phase of beryl: Raman and luminescence spectroscopy to 16.4 GPa
NASA Astrophysics Data System (ADS)
O'Bannon, Earl; Williams, Quentin
2016-10-01
The Raman and Cr3+ and V2+ luminescence spectra of beryl and emerald have been characterized up to 15.0 and 16.4 GPa, respectively. The Raman spectra show that an E 1g symmetry mode at 138 cm-1 shifts negatively by -4.57 (±0.55) cm-1/GPa, and an extrapolation of the pressure dependence of this mode indicates that a soft-mode transition should occur near 12 GPa. Such a transition is in accord with prior theoretical results. Dramatic changes in Raman mode intensities and positions occur between 11.2 and 15.0 GPa. These changes are indicative of a phase transition that primarily involves tilting and mild distortion of the Si6O18 rings. New Raman modes are not observed in the high-pressure phase, which indicates that the local bonding environment is not altered dramatically across the transition (e.g., changes in coordination do not occur). Both sharp line and broadband luminescence are observed for both Cr3+ and V2+ in emerald under compression to 16.4 GPa. The R-lines of both Cr3+ and V2+ shift to lower energy (longer wavelength) under compression. Both R-lines of Cr3+ split at ~13.7 GPa, and the V2+ R1 slope changes at this pressure and shifts more rapidly up to ~16.4 GPa. The Cr3+ R-line splitting and FWHM show more complex behavior, but also shift in behavior at ~13.7 GPa. These changes in the pressure dependency of the Cr3+ and V2+ R-lines and the changes in R-line splitting and FWHM at ~13.7 GPa further demonstrate that a phase transition occurs at this pressure, in good agreement with our Raman results. The high-pressure phase of beryl appears to have two Al sites that become more regular under compression. Hysteresis is not observed in our Raman or luminescence spectra on decompression, suggesting that this transition is second order in nature: The occurrence of a second-order transition near this pressure is also in accord with prior theoretical results. We speculate that the high-pressure phase (beryl-II) might be a mildly modulated structure, and/or that
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Dense Carbon Monoxide to 160 GPa: Stepwise Polymerization to Two-Dimensional Layered Solid
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ryu, Young-Jay; Kim, Minseob; Lim, Jinhyuk
Carbon monoxide (CO) is the first molecular system found to transform into a nonmolecular “polymeric” solid above 5.5 GPa, yet been studied beyond 10 GPa. Here, we show a series of pressure-induced phase transformations in CO to 160 GPa: from a molecular solid to a highly colored, low-density polymeric phase I to translucent, high-density phase II to transparent, layered phase III. The properties of these phases are consistent with those expected from recently predicted 1D P2 1/m, 3D I2 12 12 1, and 2D Cmcm structures, respectively. Thus, the present results advocate a stepwise polymerization of CO triple bonds tomore » ultimately a 2D singly bonded layer structure with an enhanced ionic character.« less
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NASA Astrophysics Data System (ADS)
Turner, K. M.; Rittman, D.; Heymach, R.; Turner, M.; Tracy, C.; Mao, W. L.; Ewing, R. C.
2017-12-01
Complex oxides with the pyrochlore (A2B2O7) and defect-fluorite ((A,B)4O7) structure-types undergo structural transformations under high-pressure. These compounds are under consideration for applications including as a proposed waste-form for actinides generated in the nuclear fuel cycle. High-pressure transformations in rare earth hafnates (A2Hf2O7, A=Sm, Eu, Gd, Dy, Y, Yb) and stannates (A2Sn2O7, A=Nd, Gd, Er) were investigated to 50 GPa by in situ Raman spectroscopy and synchrotron x-ray diffraction (XRD). Rare-earth hafnates form the pyrochlore structure for A=La-Tb and the defect-fluorite structure for A=Dy-Lu. Lanthanide stannates form the pyrochlore structure. Raman spectra revealed that at ambient pressure all compositions have pyrochlore-type short-range order. Stannate compositions show a larger degree of pyrochlore-type short-range ordering relative to hafnates. In situ high-pressure synchrotron XRD showed that rare earth hafnates and stannates underwent a pressure-induced phase transition to a cotunnite-like (Pnma) structure that begins between 18-25 GPa in hafnates and between 30-33 GPa in stannates. The phase transition is not complete at 50 GPa, and upon decompression, XRD indicates that all compositions transform to defect-fluorite with an amorphous component. In situ Raman spectroscopy showed that disordering in stannates and hafnates occurs gradually upon compression. Pyrochlore-structured hafnates retain short-range order to a higher pressure (30 GPa vs. <10 GPa) than defect-fluorite-structured hafnates. Hafnates and stannates decompressed from 50 GPa show Raman spectra consistent with weberite-type structures, also reported in irradiated stannates. The second-order Birch-Murnaghan equation of state fit gives a bulk modulus of 250 GPa for hafnate compositions with the pyrochlore structure, and 400 GPa for hafnate compositions with the defect-fluorite structure. Stannates have a lower bulk modulus relative to hafnates (between 80-150 GPa
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Lucas, Marcel; Winey, J. M.; Gupta, Y. M.
Previous reports of rapid phase transformation above 18 GPa [Erskine and Nellis, Nature 349, 317 (1991)] and large elastic waves below 18 GPa [Lucas et al., J. Appl. Phys. 114, 093515 (2013)] for shock-compressed ZYB-grade highly-oriented pyrolytic graphite (HOPG), but not for less oriented ZYH-grade HOPG, indicated a link between the orientational order dependence of the HOPG response above and below the phase transformation stress. To gain insight into this link and into the mechanical response of HOPG shocked to peak stresses approaching the phase transformation onset, the compressibility of ZYB- and ZYH-grade HOPG in the shocked state was examinedmore » using front surface impact experiments. Particle velocity histories and sound velocities were measured for peak stresses reaching 18 GPa. Although the locus of the measured peak stress-particle velocity states is indistinguishable for the two grades of HOPG, the measured sound velocities in the peak state reveal significant differences between the two grades. Specifically, 1) The measured sound velocities are somewhat higher for ZYH-grade HOPG, compared to ZYB-grade HOPG. 2) The measured sound velocities for ZYH-grade HOPG increase smoothly with compression, whereas those for ZYB-2 grade HOPG exhibit a significant reduction in the compression dependence from 12 GPa to 17 GPa and an abrupt increase from 17 GPa to 18 GPa. 3) The longitudinal moduli, determined from the measured sound velocities, are smaller than the calculated bulk moduli for ZYB-grade HOPG shocked to peak stresses above 15 GPa, indicating the onset of an elastic instability. The present findings demonstrate that the softening of the longitudinal modulus (or elastic instability) presented here is linked to the large elastic waves and the rapid phase transformation reported previously – all observed only for shocked ZYB-grade HOPG. The elastic instability in shocked ZYB-grade HOPG is likely a precursor to the rapid phase transformation observed
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Lucas, Marcel; Winey, J. M.; Gupta, Y. M.
2015-12-28
Previous reports of rapid phase transformation above 18 GPa [Erskine and Nellis, Nature 349, 317 (1991)] and large elastic waves below 18 GPa [Lucas et al., J. Appl. Phys. 114, 093515 (2013)] for shock-compressed ZYB-grade highly-oriented pyrolytic graphite (HOPG), but not for less oriented ZYH-grade HOPG, indicated a link between the orientational order dependence of the HOPG response above and below the phase transformation stress. To gain insight into this link and into the mechanical response of HOPG shocked to peak stresses approaching the phase transformation onset, the compressibility of ZYB- and ZYH-grade HOPG in the shocked state was examinedmore » using front surface impact experiments. Particle velocity histories and sound velocities were measured for peak stresses reaching 18 GPa. Although the locus of the measured peak stress-particle velocity states is indistinguishable for the two grades of HOPG, the measured sound velocities in the peak state reveal significant differences between the two grades. Specifically, 1) The measured sound velocities are somewhat higher for ZYH-grade HOPG, compared to ZYB-grade HOPG. 2) The measured sound velocities for ZYH-grade HOPG increase smoothly with compression, whereas those for ZYB-2 grade HOPG exhibit a significant reduction in the compression dependence from 12 GPa to 17 GPa and an abrupt increase from 17 GPa to 18 GPa. 3) The longitudinal moduli, determined from the measured sound velocities, are smaller than the calculated bulk moduli for ZYB-grade HOPG shocked to peak stresses above 15 GPa, indicating the onset of an elastic instability. The present findings demonstrate that the softening of the longitudinal modulus (or elastic instability) presented here is linked to the large elastic waves and the rapid phase transformation reported previously – all observed only for shocked ZYB-grade HOPG. The elastic instability in shocked ZYB-grade HOPG is likely a precursor to the rapid phase transformation observed
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High-pressure phases transitions in SnO2 to 117 GPa: Implications for silica
NASA Astrophysics Data System (ADS)
Shieh, S. R.; Kubo, A.; Duffy, T. S.; Prakapenka, V. B.; Shen, G.
2005-12-01
Cassiterite (SnO2) is regarded to be a good analog material for silica as both SnO2 and SiO2 are group IV-B metal dioxides. The high-pressure behavior of SnO2 has been the subject of many previous investigations extending up to 49 GPa and in addition to the rutile structure, three high-pressure phases, CaCl2-type, α-PbO2-type, and pyrite-type were observed. Better knowledge of high-pressure phases of SnO2 will be useful to understand the behavior of silica at deep mantle conditions. In addition, high-pressure metal dioxide phases may qualify as superhard solids. Our study will also provide insights into interpretation of shock compression data. Pure natural cassiterite (SnO2) powder was compressed in a diamond anvil cell using an argon medium. Pressure was determined from the equation of state of platinum. In situ monochromatic x-ray diffraction at high pressure was carried out at the GSECARS, Advanced Photon Source. High temperatures were achieved using double-sided laser heating . Three heating cycles were conducted with total heating times up to 30 minutes. Our diffraction results on SnO2 demonstrate the existence of four phase transitions to 117 GPa. The observed sequence of high-pressure phases for SnO2 is rutile-type, CaCl2-type, pyrite-type, ZrO2 orthorhombic phase I (Pbca), cotunnite-type. Our observations of the first three phases are generally in agreement with earlier studies. The orthorhombic phase I and cotunnite-type structures were observed in SnO2 for the first time. The Pbca phase is found at 50-74 GPa during room-temperature compression. The cotunnite-type structure was synthesized when SnO2 was heated at 74 GPa and 1200 K. The cotunnite-type form was observed during compression between 54-117 GPa. Fitting the pressure-volume data for the high-pressure phases to the second-order Birch-Murnaghan equation of state yields a bulk modulus of 259(26) GPa for the Pbca phase and 417(7) GPa for the cotunnite-type phase. Rietveld profile refinements were
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Structure of Mg2SiO4 glass up to 140 GPa
NASA Astrophysics Data System (ADS)
Prescher, C.; Prakapenka, V.; Wang, Y.; Skinner, L. B.
2014-12-01
The physical properties of melts at temperature and pressure conditions of the Earth's mantle have a fundamental influence on the chemical and thermal evolution of the Earth. However, direct investigations of melt structures at these conditions are experimentally very difficult or even impossible with current capabilities. In order to still be able to obtain an estimate of the structural behavior of melts at high pressures and temperatures, amorphous materials have been widely used as analogue materials. In particular the investigation of sound wave velocities of amorphous SiO2 and MgSiO3 as analogues for silicate melts indicate structural changes at about ~30-40 GPa and ~130-140 GPa [1]. The transition pressures are lower for MgSiO3 than for SiO2 indicating that these transitions are affected by the degree of polymerization of the SiO2 network of the glasses. Nevertheless, these measurements only give a hint about the occurrence of structural transitions but lack information on the actual structural changes accompanied by the sound wave velocity discontinuities. The pressure of the second structural transition at ~130-140 GPa is of vital importance for geophysics. If it causes silicate melts to become denser than the surrounding solid material, it would result in negatively buoyant melts close to the core-mantle boundary, which could be a major factor affecting the chemical stratification of the Earth's mantle during an early magma ocean after the moon forming impact. In order to resolve the structural transition and estimate the effect of a different degree of polymerization further, we studied the structural behavior of Mg2SiO4 glass up to 140 GPa using X-ray total scattering and pair distribution function analysis. The measurements were performed at the GSECARS 13-IDD beamline at the APS employing the newly developed multichannel collimator (MCC) setup. The MCC effectively removes unwanted Compton scattering of the diamond anvils and enables easy extraction of
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Shock-wave equation-of-state measurements in fused silica up to 1600 GPa
McCoy, C. A.; Gregor, M. C.; Polsin, D. N.; ...
2016-06-02
The properties of silica are important to geophysical and high-pressure equation of state research. The most prevalent crystalline form, α-quartz, has been extensively studied to TPa pressures. Recent experiments with amorphous silica, commonly referred to as fused silica, provided Hugoniot and reflectivity data up to 630 GPa using magnetically-driven aluminum impactors. This article presents measurements of the fused silica Hugoniot over the range from 200 to 1600 GPa using laser-driven shocks with a quartz standard. These results extend the measured Hugoniot of fused silica to higher pressures, but more importantly, in the 200-600 GPa range, the data are very goodmore » agreement with those obtained with a different driver and standard material. As a result, a new shock velocity-particle velocity relation is derived to fit the experimental data.« less
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Origin of mantle peridotite: Constraints from melting experiments to 16.5 GPa
NASA Astrophysics Data System (ADS)
Herzberg, Claude; Gasparik, Tibor; Sawamoto, Hiroshi
1990-09-01
Experimental data are reported for the melting of komatiite, peridotite, and chondrite compositions in the pressure range 5-16.5 GPa. All experiments were run using the multiple-anvil apparatus facilities at Nagoya and Stony Brook. Equilibrium between coexisting crystals and liquid is demonstrated to occur in less than 3 min in the 2100°C range. The anhydrous solidus in CaO-MgO-Al2O3-SiO2 has been calibrated and is shown to be about 100° higher than that for naturally occurring peridotite (KLB1). All melting curves have positive dT/dP. The effect of pressure is to expand the crystallization field of garnet at the expense of all other phases, resulting in a change in the liquidus phase from olivine to garnet at high pressures. The melting of rocks which contain the four crystalline phases olivine, orthopyroxene, clinopyroxene, and garnet is restricted to enstatite-rich compositions such as chondrite. For these it is demonstrated that melting is peritectic, rather than eutectic, and takes the form L+Opx = Ol+Cpx+Gt. Partial melting yields liquids with the following properties: 5 GPa for komatiite; and 10-15 GPa for liquid peridotite with about 40% MgO, but one that is unlike mantle peridotite in that it is distinctly enriched in silica. These results provide a test and refutation of the model that upper mantle peridotite originated by direct initial melting of a chondritic mantle (Herzberg and O'Hara, 1985). Unlike chondrite, partial melting of peridotite does not usually involve orthopyroxene. Instead, it occurs by the generation of ultrabasic liquids along a cotectic involving L+Ol+Cpx+Gt. Although the thermal and compositional characteristics of this cotectic have not been fully calibrated, it is very likely that it will degenerate into a thermal minimum (L+Ol+Cpx+Gt), compositionally similar to komatiite at 5 GPa and mantle peridotite at 10-15 GPa. Peridotite liquids that occupy a thermal minimum can be derived from those formed from the melting of chondrite by
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Structural investigation of LaAlO3 up to 63 GPa
NASA Astrophysics Data System (ADS)
Guennou, Mael; Bouvier, Pierre; Garbarino, Gaston; Kreisel, Jens
2011-10-01
We report a high-pressure synchrotron x-ray diffraction on a LaAlO3 single crystal. The transition from rhombohedral to cubic at 14.8 GPa is confirmed by the loss of the superstructure reflections, whose intensity shows a linear pressure dependence, characteristic of a second-order transition. The crystal remains cubic up to 63 GPa, the highest pressure reached, which provides a confirmation over a very large pressure range of the general rules for the evolution of distortions of perovskites under pressure. We report the parameters of the Birch-Murnaghan equations of state in the low- and high-pressure phases and discuss the evolution of the bulk modulus.
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ERIC Educational Resources Information Center
Sawyer, Richard
2013-01-01
Correlational evidence suggests that high school GPA is better than admission test scores in predicting first-year college GPA, although test scores have incremental predictive validity. The usefulness of a selection variable in making admission decisions depends in part on its predictive validity, but also on institutions' selectivity and…
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Antón, Alfonso; Pazos, Marta; Martín, Belén; Navero, José Manuel; Ayala, Miriam Eleonora; Castany, Marta; Martínez, Patricia; Bardavío, Javier
2013-01-01
To assess sensitivity, specificity, and agreement among automated event analysis, automated trend analysis, and expert evaluation to detect glaucoma progression. This was a prospective study that included 37 eyes with a follow-up of 36 months. All had glaucomatous disks and fields and performed reliable visual fields every 6 months. Each series of fields was assessed with 3 different methods: subjective assessment by 2 independent teams of glaucoma experts, glaucoma/guided progression analysis (GPA) event analysis, and GPA (visual field index-based) trend analysis. Kappa agreement coefficient between methods and sensitivity and specificity for each method using expert opinion as gold standard were calculated. The incidence of glaucoma progression was 16% to 18% in 3 years but only 3 cases showed progression with all 3 methods. Kappa agreement coefficient was high (k=0.82) between subjective expert assessment and GPA event analysis, and only moderate between these two and GPA trend analysis (k=0.57). Sensitivity and specificity for GPA event and GPA trend analysis were 71% and 96%, and 57% and 93%, respectively. The 3 methods detected similar numbers of progressing cases. The GPA event analysis and expert subjective assessment showed high agreement between them and moderate agreement with GPA trend analysis. In a period of 3 years, both methods of GPA analysis offered high specificity, event analysis showed 83% sensitivity, and trend analysis had a 66% sensitivity.
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Plastic deformation of polycrystalline MgO up to 1250 K and 65 GPa
NASA Astrophysics Data System (ADS)
Merkel, S.; Liermann, H.; Miyagi, L. M.; Wenk, H.
2009-12-01
Understanding the development of lattice preferred orientations (LPO) in polycrystals is critical to constrain the anisotropy and dynamics of the Earth mantle. Until recently, it was not possible to study LPO under high pressure and high temperature. The introduction of the deformation-DIA (D-DIA) and radial diffraction experiments in the diamond anvil cell (DAC) have extended the range of pressures and temperatures that can be accessed. However, the pressure range accessible in the D-DIA remains limited (up to 19 GPa, 1) and LPO measurements in the DAC have been performed at 300 K (2). Recently, we have designed a new DAC that can be used to study LPO in polycrystalline samples up to temperatures of 1300 K and pressures of 65 GPa (3). In this study, we use this new device for the study of MgO up to 65 GPa and 1250 K. Four samples of polycrystalline MgO were deformed in the DAC at constant temperature: 300, 600, 900, and 1250 K. At each temperature, we study the development of stress and LPO as the sample is compressed between ambient and high pressures (up to 65 GPa). In all cases, we collect diffraction data in a radial geometry that can be used to extract lattice strains and LPO in the sample. A comparison of the LPO measured in the experiment and results of visco-plastic self-consistent models can be used to extract information about the active deformation mechanisms in the sample (2). Similarly, the measured lattice strains can be compared to results of an elasto-plastic self-consistent model to extract information on average stress, stress distribution among grains, and active deformation in the sample (4). Details of the measurements along with the LPO measured in the experiments will be presented. We will also discuss the implication of those results for our understanding of the behavior of MgO in the deep mantle. 1- N. Nishiyama, Y. Wang, M. L. Rivers, S. R. Sutton, D. Cookson, Rheology of e-iron up to 19 GPa and 600 K in the D-DIA, Geophys. Res. Lett., 34
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Optical absorbances of Gd3Ga5O12 single crystals under shock compression to 211 GPa
NASA Astrophysics Data System (ADS)
Liu, Q. C.; Zhou, X. M.; Luo, S. N.
2017-04-01
Shock-induced opacity in Gd3Ga5O12 (GGG) single crystals is investigated by transmission/emission measurements at 16 wavelengths (400-800 nm), as well as complementary particle velocity measurements at 1550 nm, in the pressure range of 47-211 GPa. Optical transmission spectra through the shocked samples are measured with a in-situ, shock-generated light source, and the resultant extinction coefficients of different wavelengths and shock pressures obtained. As shock strength increases, the optical opacity of the shocked GGG increases and peaks at 75 GPa (the transparent-opaque transition), drops at 75-100 GPa (the opaque-transparent transition), and then increases again. The transparency recovery coincides with a solid-solid phase transition. The microstructure changes associated with the solid-solid phase transition and plastic deformation most likely cause the loss and recovery of transparency. GGG can be useful as a high pressure window for laser velocimetry (1550 nm) or optical pyrometry (400-800 nm) in the ranges of 100-140 GPa and 80-120 GPa, respectively.
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Phase transition and strength of vanadium under shock compression up to 88 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yu, Yuying, E-mail: yuyinyu@caep.cn; Tan, Ye; Dai, Chengda
A series of reverse-impact experiments were performed on vanadium at shock pressure ranging from 32 GPa to 88 GPa. Particle velocity profiles measured at sample/LiF window interface were used to estimate the sound velocities, shear modulus, and yield stress in shocked vanadium. A phase transition at ∼60.5 GPa that may be the body-centered cubic (BCC) to rhombohedral structure was identified by the discontinuity of the sound velocity against shock pressure. This transition pressure is consistent with the results from diamond anvil cell (DAC) experiments and first-principle calculations. However, present results show that the rhombohedral phase has higher strength and shear modulus than themore » BCC phase, which is contrast to the findings from DAC experiments and theoretical work.« less
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Forrest, Frances L; Plummer, Thomas W; Raaum, Ryan L
2018-01-01
The current study describes a new method of mandibular ecological morphology (ecomorphology). Three-dimensional geometric morphometrics (3D GM) was used to quantify mandibular shape variation between extant bovids with different feeding preferences. Landmark data were subjected to generalized Procrustes analysis (GPA), principal components analysis (PCA), and discriminant function analysis (DFA). The PCA resulted in a continuum from grazers to browsers along PC1 and DFA classified 88% or more of the modern specimens to the correct feeding category. The protocol was reduced to a subset of landmarks on the mandibular corpus in order to make it applicable to incomplete fossils. The reduced landmark set resulted in greater overlap between feeding categories but maintained the same continuum as the complete landmark model. The DFA resubstitution and jackknife analyses resulted in classification success rates of 85% and 80%, respectively. The reduced landmark model was applied to fossil mandibles from the Upper Laetolil Beds (∼4.3-3.5 Ma) and Upper Ndolanya Beds (∼2.7-2.6 Ma) at Laetoli, Tanzania in order to assess antelope diet, and indirectly evaluate paleo-vegetation structure. The majority of the fossils were classified by the DFA as browsers or mixed feeders preferring browse. Our results indicate a continuous presence of wooded habitats and are congruent with recent environmental studies at Laetoli indicating a mosaic woodland-bushland-grassland savanna ecosystem. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Development of multi-frequency ESR system for high-pressure measurements up to 2.5 GPa.
Sakurai, T; Fujimoto, K; Matsui, R; Kawasaki, K; Okubo, S; Ohta, H; Matsubayashi, K; Uwatoko, Y; Tanaka, H
2015-10-01
A new piston-cylinder pressure cell for electron spin resonance (ESR) has been developed. The pressure cell consists of a double-layer hybrid-type cylinder with internal components made of the ZrO2-based ceramics. It can generate a pressure of 2 GPa repeatedly and reaches a maximum pressure of around 2.5 GPa. A high-pressure ESR system using a cryogen-free superconducting magnet up 10T has also been developed for this hybrid-type pressure cell. The frequency region is from 50 GHz to 400 GHz. This is the first time a pressure above 2 GPa has been achieved in multi-frequency ESR system using a piston-cylinder pressure cell. We demonstrate its potential by showing the results of the high-pressure ESR of the S=1 system with the single ion anisotropy NiSnCl6·6H2O and the S=1/2 quantum spin system CsCuCl3. We performed ESR measurements of these systems above 2 GPa successfully. Copyright © 2015 Elsevier Inc. All rights reserved.
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Development of multi-frequency ESR system for high-pressure measurements up to 2.5 GPa
NASA Astrophysics Data System (ADS)
Sakurai, T.; Fujimoto, K.; Matsui, R.; Kawasaki, K.; Okubo, S.; Ohta, H.; Matsubayashi, K.; Uwatoko, Y.; Tanaka, H.
2015-10-01
A new piston-cylinder pressure cell for electron spin resonance (ESR) has been developed. The pressure cell consists of a double-layer hybrid-type cylinder with internal components made of the ZrO2-based ceramics. It can generate a pressure of 2 GPa repeatedly and reaches a maximum pressure of around 2.5 GPa. A high-pressure ESR system using a cryogen-free superconducting magnet up 10 T has also been developed for this hybrid-type pressure cell. The frequency region is from 50 GHz to 400 GHz. This is the first time a pressure above 2 GPa has been achieved in multi-frequency ESR system using a piston-cylinder pressure cell. We demonstrate its potential by showing the results of the high-pressure ESR of the S = 1 system with the single ion anisotropy NiSnCl6 · 6H2O and the S = 1 / 2 quantum spin system CsCuCl3. We performed ESR measurements of these systems above 2 GPa successfully.
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Phase diagram of antimony up to 31 GPa and 835 K
NASA Astrophysics Data System (ADS)
Coleman, A. L.; Stevenson, M.; McMahon, M. I.; Macleod, S. G.
2018-04-01
X-ray powder diffraction experiments using resistively heated diamond anvil cells have been conducted in order to establish the phase behavior of antimony up to 31 GPa and 835 K. The dip in the melting curve at 5.7 GPa and 840 K is identified as the triple point between the Sb-I, incommensurate Sb-II, and liquid phases. No evidence of the previously reported simple cubic phase was observed. Determination of the phase boundary between Sb-II and Sb-III suggests the existence of a second triple point in the region of 13 GPa and 1200 K. The incommensurate composite structure of Sb-II was found to remain ordered to the highest temperatures studies—no evidence of disordering of the guest-atom chains was observed. Indeed, the modulation reflections that arise from interactions between the host and guest subsystems were found to be present to the highest temperatures, suggesting such interactions remain relatively strong in Sb even in the presence of increased thermal motion. Finally, we show that the incommensurately modulated structure recently reported as giving an improved fit to diffraction data from incommensurate Ba-IV can be rejected as the structure of Sb-II using a simple density argument.
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Optical Absorption and Raman Spectroscopy of Multiple Shocked Liquid Benzene to 10 GPa
NASA Astrophysics Data System (ADS)
Root, S.
2005-07-01
Liquid benzene samples were multiply shocked to peak pressures ranging from 3 GPa to 10 GPa to examine physical and chemical changes in benzene. A xenon flashlamp was used to probe the visible spectrum of benzene for loses in transmitted light intensity caused by changes in the electronic structure (absorption) or a possible liquid to solid phase transition (scattering). Raman spectroscopy was used to corroborate transmission measurements by examining changes in the benzene vibrational modes. The C-C symmetric ring breathing mode (992 cm-1), C-H symmetric stretch (3061 cm-1), along with several weaker modes at 607 cm-1, 1178 cm-1, 1586 cm-1, and 1606 cm-1 were monitored during shock loading. An EOS was developed to calculate the temperature of the shock compressed benzene. The present work has demonstrated that liquid benzene remains unchanged during multiple shock loading up to 10 GPa. Work supported by ONR and DOE.
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ERIC Educational Resources Information Center
Ginther, April; Yan, Xun
2018-01-01
This study examines the predictive validity of the TOEFL iBT with respect to academic achievement as measured by the first-year grade point average (GPA) of Chinese students at Purdue University, a large, public, Research I institution in Indiana, USA. Correlations between GPA, TOEFL iBT total and subsection scores were examined on 1990 mainland…
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NMR at pressures up to 90 GPa.
Meier, Thomas; Khandarkhaeva, Saiana; Petitgirard, Sylvain; Körber, Thomas; Lauerer, Alexander; Rössler, Ernst; Dubrovinsky, Leonid
2018-05-14
The past 15 years have seen an astonishing increase in Nuclear Magnetic Resonance (NMR) sensitivity and accessible pressure range in high-pressure NMR experiments, owing to a series of new developments of NMR spectroscopy applied to the diamond anvil cell (DAC). Recently, with the application of electro-magnetic lenses, so-called Lenz lenses, in toroidal diamond indenter cells, pressures of up to 72 GPa with NMR spin sensitivities of about 10 12 spin/Hz 1/2 has been achieved. Here, we describe the implementation of a refined NMR resonator structure using a pair of double stage Lenz lenses driven by a Helmholtz coil within a standard DAC, allowing to measure sample volumes as small as 100 pl prior to compression. With this set-up, pressures close to 100 GPa could be realised repeatedly, with enhanced spin sensitivities of about 5 × 10 11 spin/Hz 1/2 . The manufacturing and handling of these new NMR-DACs is relatively easy and straightforward, which will allow for further applications in physics, chemistry, or biochemistry. Copyright © 2018 Elsevier Inc. All rights reserved.
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Kimura, T; Kuwayama, Y; Yagi, T
2014-02-21
The melting curve of H2O from 49 to 72 GPa was determined by using a laser-heated diamond anvil cell. Double-sided CO2 laser heating technique was employed in order to heat the sample directly. Discontinuous changes of the heating efficiency attributed to the H2O melting were observed between 49 and 72 GPa. The obtained melting temperatures at 49 and 72 GPa are 1200 and 1410 K, respectively. We found that the slope of the melting curve significantly decreases with increasing pressure, only 5 K/GPa at 72 GPa while 44 K/GPa at 49 GPa. Our results suggest that the melting curve does not intersect with the isentropes of Uranus and Neptune, and hence, H2O should remain in the liquid state even at the pressure and temperature conditions found deep within Uranus and Neptune.
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High-pressure structural parameters and equation of state of osmium to 207 GPa
Perreault, Christopher S.; Velisavljevic, Nenad; Vohra, Yogesh K.; ...
2017-09-08
We studied the most incompressible transition metal osmium (Os) under high pressure. There is significant interest in Os because of the structural anomalies attributed to topological transitions in the Fermi surface for valence electrons in the hexagonal close-packed phase. We report on measurements of structural parameters and equation of state on Os metal to a pressure of 207 GPa at ambient temperature using platinum as a pressure standard. We also obtained angle-dispersive X-ray diffraction data at a synchrotron source with closely spaced pressure intervals to observe any discontinuities or anomalies in the axial c/a ratio at high pressures. Rietveld refinementsmore » of X-ray diffraction data show a slowly varying axial ratio (c/a) with a broad minimum at 75 GPa. Our data do not provide any evidence of anomalous behavior in the c/a ratio in Os at 25 or 150 GPa as have been reported in previous studies. These experimental results are in agreement with theoretical calculations that do not predict any anomalous behavior in c/a ratio in Os under extreme conditions. We present an equation of state for Os to 207 GPa (V/V 0 = 0.761) at ambient temperature and compare our results with the previously published data.« less
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High-pressure structural parameters and equation of state of osmium to 207 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Perreault, Christopher S.; Velisavljevic, Nenad; Vohra, Yogesh K.
We studied the most incompressible transition metal osmium (Os) under high pressure. There is significant interest in Os because of the structural anomalies attributed to topological transitions in the Fermi surface for valence electrons in the hexagonal close-packed phase. We report on measurements of structural parameters and equation of state on Os metal to a pressure of 207 GPa at ambient temperature using platinum as a pressure standard. We also obtained angle-dispersive X-ray diffraction data at a synchrotron source with closely spaced pressure intervals to observe any discontinuities or anomalies in the axial c/a ratio at high pressures. Rietveld refinementsmore » of X-ray diffraction data show a slowly varying axial ratio (c/a) with a broad minimum at 75 GPa. Our data do not provide any evidence of anomalous behavior in the c/a ratio in Os at 25 or 150 GPa as have been reported in previous studies. These experimental results are in agreement with theoretical calculations that do not predict any anomalous behavior in c/a ratio in Os under extreme conditions. We present an equation of state for Os to 207 GPa (V/V 0 = 0.761) at ambient temperature and compare our results with the previously published data.« less
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Flinner, Nadine; Mirus, Oliver; Schleiff, Enrico
2014-08-15
The hydrophobic thickness of membranes, which is manly defined by fatty acids, influences the packing of transmembrane domains of proteins and thus can modulate the activity of these proteins. We analyzed the dynamics of the dimerization of Glycophorin A (GpA) by molecular dynamics simulations to describe the fatty acid dependence of the transmembrane region assembly. GpA represents a well-established model for dimerization of single transmembrane helices containing a GxxxG motif in vitro and in silico. We performed simulations of the dynamics of the NMR-derived dimer as well as self-assembly simulations of monomers in membranes composed of different fatty acid chains and monitored the formed interfaces and their transitions. The observed dimeric interfaces, which also include the one known from NMR, are highly dynamic and converted into each other. The frequency of interface formation and the preferred transitions between interfaces similar to the interface observed by NMR analysis strongly depend on the fatty acid used to build the membrane. Molecular dynamic simulations after adaptation of the helix topology parameters to better represent NMR derived structures of single transmembrane helices yielded an enhanced occurrence of the interface determined by NMR in molecular dynamics simulations. Taken together we give insights into the influence of fatty acids and helix conformation on the dynamics of the transmembrane domain of GpA.
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Flinner, Nadine; Mirus, Oliver; Schleiff, Enrico
2014-01-01
The hydrophobic thickness of membranes, which is manly defined by fatty acids, influences the packing of transmembrane domains of proteins and thus can modulate the activity of these proteins. We analyzed the dynamics of the dimerization of Glycophorin A (GpA) by molecular dynamics simulations to describe the fatty acid dependence of the transmembrane region assembly. GpA represents a well-established model for dimerization of single transmembrane helices containing a GxxxG motif in vitro and in silico. We performed simulations of the dynamics of the NMR-derived dimer as well as self-assembly simulations of monomers in membranes composed of different fatty acid chains and monitored the formed interfaces and their transitions. The observed dimeric interfaces, which also include the one known from NMR, are highly dynamic and converted into each other. The frequency of interface formation and the preferred transitions between interfaces similar to the interface observed by NMR analysis strongly depend on the fatty acid used to build the membrane. Molecular dynamic simulations after adaptation of the helix topology parameters to better represent NMR derived structures of single transmembrane helices yielded an enhanced occurrence of the interface determined by NMR in molecular dynamics simulations. Taken together we give insights into the influence of fatty acids and helix conformation on the dynamics of the transmembrane domain of GpA. PMID:25196522
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Lockwood, Charles A; Lynch, John M; Kimbel, William H
2002-12-01
The hominid temporal bone offers a complex array of morphology that is linked to several different functional systems. Its frequent preservation in the fossil record gives the temporal bone added significance in the study of human evolution, but its morphology has proven difficult to quantify. In this study we use techniques of 3D geometric morphometrics to quantify differences among humans and great apes and discuss the results in a phylogenetic context. Twenty-three landmarks on the ectocranial surface of the temporal bone provide a high level of anatomical detail. Generalized Procrustes analysis (GPA) is used to register (adjust for position, orientation and scale) landmark data from 405 adults representing Homo, Pan, Gorilla and Pongo. Principal components analysis of residuals from the GPA shows that the major source of variation is between humans and apes. Human characteristics such as a coronally orientated petrous axis, a deep mandibular fossa, a projecting mastoid process, and reduced lateral extension of the tympanic element strongly impact the analysis. In phenetic cluster analyses, gorillas and orangutans group together with respect to chimpanzees, and all apes group together with respect to humans. Thus, the analysis contradicts depictions of African apes as a single morphotype. Gorillas and orangutans lack the extensive preglenoid surface of chimpanzees, and their mastoid processes are less medially inflected. These and other characters shared by gorillas and orangutans are probably primitive for the African hominid clade.
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Lockwood, Charles A; Lynch, John M; Kimbel, William H
2002-01-01
The hominid temporal bone offers a complex array of morphology that is linked to several different functional systems. Its frequent preservation in the fossil record gives the temporal bone added significance in the study of human evolution, but its morphology has proven difficult to quantify. In this study we use techniques of 3D geometric morphometrics to quantify differences among humans and great apes and discuss the results in a phylogenetic context. Twenty-three landmarks on the ectocranial surface of the temporal bone provide a high level of anatomical detail. Generalized Procrustes analysis (GPA) is used to register (adjust for position, orientation and scale) landmark data from 405 adults representing Homo, Pan, Gorilla and Pongo. Principal components analysis of residuals from the GPA shows that the major source of variation is between humans and apes. Human characteristics such as a coronally orientated petrous axis, a deep mandibular fossa, a projecting mastoid process, and reduced lateral extension of the tympanic element strongly impact the analysis. In phenetic cluster analyses, gorillas and orangutans group together with respect to chimpanzees, and all apes group together with respect to humans. Thus, the analysis contradicts depictions of African apes as a single morphotype. Gorillas and orangutans lack the extensive preglenoid surface of chimpanzees, and their mastoid processes are less medially inflected. These and other characters shared by gorillas and orangutans are probably primitive for the African hominid clade. PMID:12489757
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Self-diffusion of protons in H{sub 2}O ice VII at high pressures: Anomaly around 10 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Noguchi, Naoki, E-mail: noguchi-n@okayama-u.ac.jp; Okuchi, Takuo
2016-06-21
The self-diffusion of ice VII in the pressure range of 5.5–17 GPa and temperature range of 400–425 K was studied using micro Raman spectroscopy and a diamond anvil cell. The diffusion was monitored by observing the distribution of isotope tracers: D{sub 2}O and H{sub 2}{sup 18}O. The diffusion coefficient of hydrogen reached a maximum value around 10 GPa. It was two orders of magnitude greater at 10 GPa than at 6 GPa. Hydrogen diffusion was much faster than oxygen diffusion, which indicates that protonic diffusion is the dominant mechanism for the diffusion of hydrogen in ice VII. This mechanism ismore » in remarkable contrast to the self-diffusion in ice I{sub h} that is dominated by an interstitial mechanism for the whole water molecule. An anomaly around 10 GPa in ice VII indicates that the rate-determining process for the proton diffusion changes from the diffusion of ionic defects to the diffusion of rotational defects, which was suggested by proton conductivity measurements and molecular dynamics simulations.« less
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Single-shot Ellipsometry of Shocked Iron to 275 GPa
NASA Astrophysics Data System (ADS)
Grant, Sean; Ao, Tommy; Bernstein, Aaron; Davis, Jean-Paul; Ditmire, Todd; Dolan, Daniel; Lin, Jung-Fu; Porwitzky, Andrew; Seagle, Christopher
2017-06-01
We have studied the properties of iron under shock conditions using time-resolved ellipsometry, a technique that probes the dielectric value of materials under dynamic conditions, on the STAR gas gun facility at Sandia National Laboratories. We performed experiments on a two-stage gas gun ranging from the α - ɛ transition (75 GPa) to the solid-liquid transition (275 GPa). For the first time, we report the dielectric results of shocked iron at those conditions. In addition, the time-resolved ellipsometry diagnostic is being implemented on the Sandia pulsed power Z-machine. The goal of upcoming Z experiments will be to employ the ``shock-ramp'' technique to reach pressure and temperature conditions relevant to the Earth core, and to use ellipsometry to obtain the iron electric conductivities needed for benchmarking material models. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2017-1952 A.
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ERIC Educational Resources Information Center
Caskie, Grace I. L.; Sutton, MaryAnn C.; Eckhardt, Amanda G.
2014-01-01
Assessments of college academic achievement tend to rely on self-reported GPA values, yet evidence is limited regarding the accuracy of those values. With a sample of 194 undergraduate college students, the present study examined whether accuracy of self-reported GPA differed based on level of academic performance or level of academic…
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Sanz, Delia Nieto; Loubeyre, Paul; Mezouar, Mohamed
2002-12-09
The equation of state of boron has been measured up to 100 GPa by single-crystal x-ray diffraction with helium as the pressure transmitting medium. Rhombohedral beta-boron is the stable structure up to 100 GPa under hydrostatic conditions. Nonhydrostatic stress stabilizes a different rhombohedral structure. At about 100 GPa a pressure-induced amorphization is observed. The amorphous phase can be quenched to ambient pressure. An explanation is proposed based on the different stability under pressure between intraicosahedra and intericosahedra bonds.
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Partial melting of carbonated pelite at 3-7 GPa and deep cycling of CO2 and H2O in subduction zones
NASA Astrophysics Data System (ADS)
Tsuno, K.; Dasgupta, R.; Danielson, L. R.; Righter, K.
2011-12-01
The exchange of water and carbon dioxide between the Earth's crustal rocks and the interior is important for understanding geochemical and geophysical evolution of the planet on geologic timescale. Subduction of pelitic sediments is a key mechanism for volatile introduction to the mantle but the high-pressure behavior of H2O+ CO2 bearing sediments is only constrained for alumina-rich, low-Mg# bulk compositions [1, 2]. However, the ocean-floor sediments for many subduction zones that contain both water and CO2 are alumina-poor and have higher Mg#. To constrain the melting behavior of a model alumina poor carbonated pelite, we performed new experiments. Piston cylinder (3 GPa) and multianvil (5 and 7 GPa) experiments were conducted between 800 and 1150 °C, using a model sediment composition containing 1 wt.% H2O and 5 wt.% CO2 (trace vapor-present at subsolidus conditions). The choice of the bulk composition was aimed to model the loss of siliceous hydrous fluid during the shallow part of subduction. We determined the solidus temperatures between 800 and 850 °C at 3 GPa, 900 and 950 °C at 5 GPa, and <1000 °C at 7 GPa. The subsolidus phases include cpx, garnet, coesite, rutile, phengite, and calcitess at 3 GPa, and kyanite comes in at 5 GPa. Hydrous rhyolitic silicate melt was observed at 3 GPa and up to 1150 °C. The near-solidus melt at 5-7 GPa was K-rich and calcio-carbonatitic, in contrast to the previous experimental results in alumina-rich and low Mg# bulk composition [1, 2], which showed the stability of Al-rich trachyitic silicate melt at near-solidus temperatures up to 5 GPa, and replaced by carbonate melt only at ≥5.5 GPa. Carbonate-silicate melt immiscibility was observed at 5 GPa, 1100 °C in our study. The phengite-out boundary is located between 850 and 900 °C at 3 GPa, between 1000 and 1100 °C at 5 GPa, and <1000 °C at 7 GPa. The crystalline carbonate-out boundary is between 950 and 1000 °C at 3 and 5 GPa, and <1000 °C at 7 GPa. Comparison of
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P-V-T equation of state of CaCO3 aragonite to 29 GPa and 1673 K: In situ X-ray diffraction study
NASA Astrophysics Data System (ADS)
Litasov, Konstantin D.; Shatskiy, Anton; Gavryushkin, Pavel N.; Bekhtenova, Altyna E.; Dorogokupets, Peter I.; Danilov, Boris S.; Higo, Yuji; Akilbekov, Abdirash T.; Inerbaev, Talgat M.
2017-04-01
Pressure-volume-temperature relations have been measured to 29 GPa and 1673 K for CaCO3 aragonite using synchrotron X-ray diffraction with a multianvil apparatus at the 'SPring-8' facility. A least-squares fit of the room-temperature compression data to the Vinet-Rydberg equation of state (EOS) yielded KT0 = 65.7 ± 0.8 GPa and KT' = 5.1 ± 0.1, with fixed V0 = 227.11 Å3. Further analysis of the high-temperature compression data led to the temperature derivative of the bulk modulus (∂KT/∂T)P = -0.016 ± 0.001 GPa/K and zero-pressure thermal expansion α = a0 + a1T with a0 = 4.98 (22) × 10-5 K-1 and a1 = 2.81(38) × 10-8 K-2. The Mie-Gruneisen-Debye approach revealed the Gruneisen parameter γ0 = 1.39 at a fixed Debye temperature θ0 = 516 K and the parameter q = 1. Analysis of axial compressibility and thermal expansion indicates that the c-axis is two times more compressible than the b-axis and four times more compressible than the a-axis, whereas zero-pressure thermal expansion of the a-axis (a0a = 2.6 × 10-5 K-1 and a1a = 2.3 × 10-8 K-2) is weaker than that of the b-axis axis (a0b = 6.3 × 10-5 K-1 and a1b = 0.1 × 10-8 K-2) and c-axis axis (a0c = 5.2 × 10-5 K-1 and a1c = 9.5 × 10-8 K-2). A full set of thermodynamic parameters (including heat capacity, enthalpy and free energy) for aragonite and updated equations of state for magnesite and siderite was obtained using the Kunc-Einstein approach. The new EOS parameters were used for thermodynamic calculations for aragonite decarbonation reactions. The present thermal EOS provides accurate calculations of aragonite density to deep mantle. Decarbonation of subducting oceanic crust containing 2 wt% aragonite would result in a 0.5% density reduction at 30 GPa and 1273 K. Aragonite becomes denser than magnesite at pressures about 16 GPa along the 1500 K isotherm and at 9 GPa along the 298 K isotherm.
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The study of craniofacial growth patterns using 3D laser scanning and geometric morphometrics
NASA Astrophysics Data System (ADS)
Friess, Martin
2006-02-01
Throughout childhood, braincase and face grow at different rates and therefore exhibit variable proportions and positions relative to each other. Our understanding of the direction and magnitude of these growth patterns is crucial for many ergonomic applications and can be improved by advanced 3D morphometrics. The purpose of this study is to investigate this known growth allometry using 3D imaging techniques. The geometry of the head and face of 840 children, aged 2 to 19, was captured with a laser surface scanner and analyzed statistically. From each scan, 18 landmarks were extracted and registered using General Procrustes Analysis (GPA). GPA eliminates unwanted variation due to position, orientation and scale by applying a least-squares superimposition algorithm to individual landmark configurations. This approach provides the necessary normalization for the study of differences in size, shape, and their interaction (allometry). The results show that throughout adolescence, boys and girls follow a different growth trajectory, leading to marked differences not only in size but also in shape, most notably in relative proportions of the braincase. These differences can be observed during early childhood, but become most noticeable after the age of 13 years, when craniofacial growth in girls slows down significantly, whereas growth in boys continues for at least 3 more years.
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3-Fluorosalicylaldoxime at 6.5 GPa
Wood, Peter A.; Forgan, Ross S.; Parsons, Simon; Pidcock, Elna; Tasker, Peter A.
2009-01-01
3-Fluorosalicylaldoxime, C7H6FNO2, unlike many salicylaldoxime derivatives, forms a crystal structure containing hydrogen-bonded chains rather than centrosymmetric hydrogen-bonded ring motifs. Each chain interacts with two chains above and two chains below via π–π stacking contacts [shortest centroid–centroid distance = 3.295 (1) Å]. This structure at 6.5 GPa represents the final point in a single-crystal compression study. PMID:21583672
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NASA Astrophysics Data System (ADS)
Liu, Xi; Fleet, Michael E.; Shieh, Sean R.; He, Qiang
2011-05-01
Lead bromapatite [Pb10(PO4)6Br2] has been synthesized via solid-state reaction at pressures up to 1.0 GPa, and its structure determined by single-crystal X-ray diffraction at ambient temperature and pressure. The large bromide anion is accommodated in the c-axis channel by lateral displacements of structural elements, particularly of Pb2 cations and PO4 tetrahedra. The compressibility of bromapatite was also investigated up to about 20.7 GPa at ambient temperature, using a diamond-anvil cell and synchrotron X-ray radiation. The compressibility of lead bromapatite is significantly different from that of lead fluorapatite. The pressure-volume data of lead bromapatite ( P < 10 GPa) fitted to the third-order Birch-Murnaghan equation yield an isothermal bulk modulus ( K T ) of 49.8(16) GPa and first pressure derivative ( KT^' } ) of 10.1(10). If KT^' } is fixed at 4, the derived K T is 60.8(11) GPa. The relative difference of the bulk moduli of these two lead apatites is thus about 12%, which is about two times the relative difference of the bulk moduli (~5%) of the calcium apatites fluorapatite [Ca10(PO4)6F2], chlorapatite [Ca10(PO4)6Cl2] and hydroxylapatite [Ca10(PO4)6(OH)2]. Another interesting feature apparently related to the replacement of F by Br in lead apatite is the switch in the principle axes of the strain ellipsoid: the c-axis is less compressible than the a-axis in lead bromapatite but more compressible in lead fluorapatite.
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Melting relations in the MgO-MgSiO3 system up to 70 GPa
NASA Astrophysics Data System (ADS)
Ohnishi, Satoka; Kuwayama, Yasuhiro; Inoue, Toru
2017-06-01
Melting experiments in a binary system MgO-MgSiO3 were performed up to 70 GPa using a CO2 laser heated diamond anvil cell. The quenched samples were polished and analyzed by a dualbeam focused ion beam (FIB) and a field emission scanning electron microscope (FE-SEM), respectively. The liquidus phase and the eutectic composition were determined on the basis of textual and chemical analyses of sample cross sections. Our experimental results show that the eutectic composition is the Si/Mg molar ratio of 0.76 at 35 GPa and it decreases with increasing pressure. Above 45 GPa, it becomes relatively constant at about 0.64-0.65 Si/Mg molar ratio. Using our experimental data collected at a wide pressure range up to 70 GPa together with previous experimental data, we have constructed a thermodynamic model of the eutectic composition of the MgO-MgSiO3 system. The eutectic composition extrapolated to the pressure and temperature conditions at the base of the mantle is about 0.64 Si/Mg molar ratio. The modeled eutectic composition is quite consistent with a previous prediction from ab initio calculations (de Koker et al. in Earth Planet Sci Lett 361:58-63, 2013), suggesting that the simple assumption of a non-ideal regular solution model can well describe the melting relation of the MgO-MgSiO3 system at high pressure. Our results show that the liquidus phase changes from MgO-periclase to MgSiO3-bridgmanite at 35 GPa for the simplified pyrolite composition ( 0.7 Si/Mg molar ratio), while MgSiO3-bridgmanite is the liquidus phase at the entire lower mantle conditions for the chondritic composition ( 0.84 Si/Mg molar ratio).
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GMAT and Other Determinants of GPA in an MBA Program
ERIC Educational Resources Information Center
Fairfield-Sonn, James W.; Kolluri, Bharat; Singamsetti, Rao; Wahab, Mahmoud
2010-01-01
This paper reports on the influence of waiving the GMAT requirement on academic performance as measured by grade-point-average at graduation for 833 University of Hartford MBA students who graduated between 2003 and 2009. In seeking to better understand what factors might be influencing graduation GPA, we examined a variety of traditional…
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Daboul, Amro; Ivanovska, Tatyana; Bülow, Robin; Biffar, Reiner; Cardini, Andrea
2018-01-01
Using 3D anatomical landmarks from adult human head MRIs, we assessed the magnitude of inter-operator differences in Procrustes-based geometric morphometric analyses. An in depth analysis of both absolute and relative error was performed in a subsample of individuals with replicated digitization by three different operators. The effect of inter-operator differences was also explored in a large sample of more than 900 individuals. Although absolute error was not unusual for MRI measurements, including bone landmarks, shape was particularly affected by differences among operators, with up to more than 30% of sample variation accounted for by this type of error. The magnitude of the bias was such that it dominated the main pattern of bone and total (all landmarks included) shape variation, largely surpassing the effect of sex differences between hundreds of men and women. In contrast, however, we found higher reproducibility in soft-tissue nasal landmarks, despite relatively larger errors in estimates of nasal size. Our study exemplifies the assessment of measurement error using geometric morphometrics on landmarks from MRIs and stresses the importance of relating it to total sample variance within the specific methodological framework being used. In summary, precise landmarks may not necessarily imply negligible errors, especially in shape data; indeed, size and shape may be differentially impacted by measurement error and different types of landmarks may have relatively larger or smaller errors. Importantly, and consistently with other recent studies using geometric morphometrics on digital images (which, however, were not specific to MRI data), this study showed that inter-operator biases can be a major source of error in the analysis of large samples, as those that are becoming increasingly common in the 'era of big data'.
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Ivanovska, Tatyana; Bülow, Robin; Biffar, Reiner; Cardini, Andrea
2018-01-01
Using 3D anatomical landmarks from adult human head MRIs, we assessed the magnitude of inter-operator differences in Procrustes-based geometric morphometric analyses. An in depth analysis of both absolute and relative error was performed in a subsample of individuals with replicated digitization by three different operators. The effect of inter-operator differences was also explored in a large sample of more than 900 individuals. Although absolute error was not unusual for MRI measurements, including bone landmarks, shape was particularly affected by differences among operators, with up to more than 30% of sample variation accounted for by this type of error. The magnitude of the bias was such that it dominated the main pattern of bone and total (all landmarks included) shape variation, largely surpassing the effect of sex differences between hundreds of men and women. In contrast, however, we found higher reproducibility in soft-tissue nasal landmarks, despite relatively larger errors in estimates of nasal size. Our study exemplifies the assessment of measurement error using geometric morphometrics on landmarks from MRIs and stresses the importance of relating it to total sample variance within the specific methodological framework being used. In summary, precise landmarks may not necessarily imply negligible errors, especially in shape data; indeed, size and shape may be differentially impacted by measurement error and different types of landmarks may have relatively larger or smaller errors. Importantly, and consistently with other recent studies using geometric morphometrics on digital images (which, however, were not specific to MRI data), this study showed that inter-operator biases can be a major source of error in the analysis of large samples, as those that are becoming increasingly common in the 'era of big data'. PMID:29787586
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Three-dimensional gender differences in facial form of children in the North East of England.
Bugaighis, Iman; Mattick, Clare R; Tiddeman, Bernard; Hobson, Ross
2013-06-01
The aim of the prospective cross-sectional morphometric study was to explore three dimensional (3D) facial shape and form (shape plus size) variation within and between 8- and 12-year-old Caucasian children; 39 males age-matched with 41 females. The 3D images were captured using a stereophotogrammeteric system, and facial form was recorded by digitizing 39 anthropometric landmarks for each scan. The x, y, z coordinates of each landmark were extracted and used to calculate linear and angular measurements. 3D landmark asymmetry was quantified using Generalized Procrustes Analysis (GPA) and an average face was constructed for each gender. The average faces were superimposed and differences were visualized and quantified. Shape variations were explored using GPA and PrincipalComponent Analysis. Analysis of covariance and Pearson correlation coefficients were used to explore gender differences and to determine any correlation between facial measurements and height or weight. Multivariate analysis was used to ascertain differences in facial measurements or 3D landmark asymmetry. There were no differences in height or weight between genders. There was a significant positive correlation between facial measurements and height and weight and statistically significant differences in linear facial width measurements between genders. These differences were related to the larger size of males rather than differences in shape. There were no age- or gender-linked significant differences in 3D landmark asymmetry. Shape analysis confirmed similarities between both males and females for facial shape and form in 8- to 12-year-old children. Any differences found were related to differences in facial size rather than shape.
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The elastic constants of San Carlos olivine to 17 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Abramson, E.H.; Brown, J.M.; Slutsky, L.J.
1997-06-01
All elastic constants, the average bulk and shear moduli, and the lattice parameters of San Carlos olivine (Fo{sub 90}) (initial density 3.355gm/cm{sup 3}) have been determined to a pressure of 12 GPa at room temperature. Measurements of c{sub 11}, c{sub 33}, c{sub 13}, and c{sub 55} have been extended to 17 GPa. The pressure dependence of the adiabatic, isotropic (Hashin-Shtrikman bounds) bulk modulus, and shear modulus may be expressed as K{sub HS}=129.4+4.29P and by G{sub HS}=78+1.71P{minus}0.027P{sup 2}, where both the pressure and the moduli are in gigapascals. The isothermal compression of olivine is described by a bulk modulus given asmore » K{sub T}=126.3+4.28P. Elastic constants other than c{sub 55} can be adequately represented by a linear relationship in pressure. In the order (c{sub 11},c{sub 12},c{sub 13},c{sub 22},c{sub 23},c{sub 33},c{sub 44},c{sub 55},c{sub 66}) the 1 bar intercepts (gigapascal units) are (320.5, 68.1, 71.6, 196.5, 76.8, 233.5, 64.0, 77.0, 78.7). The first derivatives are (6.54, 3.86, 3.57, 5.38, 3.37, 5.51, 1.67, 1.81, 1.93). The second derivative for c{sub 55} is {minus}0.070GPa{sup {minus}1}. Incompressibilities for the three axes may also be expressed as linear relationships with pressure. In the order of {bold a, b}, and {bold c} axes the intercepts in gigapascals are (547.8, 285.8, 381.8) and the first derivatives are (20.1, 12.3, 14.0).{copyright} 1997 American Geophysical Union« less
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Electrical resistivity of fluid methane multiply shock compressed to 147 GPa
NASA Astrophysics Data System (ADS)
Wang, Yi-Gao; Liu, Fu-Sheng; Liu, Qi-Jun; Wang, Wen-Peng
2018-01-01
Shock wave experiments were carried out to measure the electrical resistivity of fluid methane. The pressure range of 89-147 GPa and the temperature range from 1800 to 2600 K were achieved with a two-stage light-gas gun. We obtained a minimum electrical resistivity value of 4.5 × 10-2 Ω cm at pressure and temperature of 147 GPa and 2600 K, which is two orders of magnitude higher than that of hydrogen under similar conditions. The data are interpreted in terms of a continuous transition from insulator to semiconductor state. One possibility reason is chemical decomposition of methane in the shock compression process. Along density and temperature increase with Hugoniot pressure, dissociation of fluid methane increases continuously to form a H2-rich fluid.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Amulele, George M.; Manghnani, Murli H.; Marriappan, Sekar
2008-07-23
The equations of state (pressure-volume relations) for WC and WC-6%Co have been determined by synchrotron x-ray diffraction measurements on polycrystalline powder samples loaded in a diamond anvil cell as well as by ultrasonic measurements on hot-pressed polycrystalline, cylindrical samples loaded in a multianvil high-pressure apparatus. The third-order Birch-Murnaghan equation of state fitted to the x-ray diffraction pressure-density sets of data, collected up to 50 GPa, yields ambient pressure isothermal bulk moduli of K{sub oT} = 411.8{+-}12.1 GPa and K{sub oT} = 402.4{+-}14.1 GPa, with pressure derivatives of K{sub oT}' = 5.45{+-}0.73 and K{sub oT}' = 7.50{+-}0.86 for WC and WC-6%Co,more » respectively. The ultrasonic measurements, conducted up to 14 GPa, enabled the determination of the pressure dependences of both bulk and shear moduli. Using Eulerian finite strain equations to fit the ultrasonic data, we obtain for WC an ambient pressure adiabatic bulk modulus of K{sub os} = 383.8{+-}0.8 GPa, and K{sub os}' = 2.61{+-}0.07 for its pressure derivative, while values of G{sub os} = 304.0{+-}0.3 GPa and G{sub os}' = 1.50{+-}0.09 were determined for the shear modulus and its pressure derivative, respectively. Meanwhile, for WC-6%Co, we obtain K{sub os} = 357.5{+-}1.0 GPa, K{sub os}' = 5.18{+-}0.14, G{sub os} = 253.5{+-}0.3 GPa, and G{sub os}' = 1.09{+-}0.09. The equations of state derived from the ultrasonic data are in good agreement with extrapolated results reported previously by Day and Ruoff [J. Appl. Phys. 44, 2447 (1973)] and Gerlich and Kennedy [J. Appl. Phys. 50, 3331 (1978)] who carried out measurements up to 0.2 and 1.0 GPa, respectively.« less
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ERIC Educational Resources Information Center
Wielkiewicz, Richard M.; Prom, Christina L.; Loos, Steven
2005-01-01
The Leadership Attitudes and Beliefs Scale (LABS-III; Wielkiewicz, 2000) was validated against a measure with a more traditional, position-based definition of leadership. Disagreement with Hierarchical Thinking was associated with a higher GPA. A Life-Long Learning scale was strongly associated with GPA, Systemic Thinking, and social activism.…
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Phase relation of CaSO4 at high pressure and temperature up to 90 GPa and 2300 K
NASA Astrophysics Data System (ADS)
Fujii, Taku; Ohfuji, Hiroaki; Inoue, Toru
2016-05-01
Calcium sulfate (CaSO4), one of the major sulfate minerals in the Earth's crust, is expected to play a major role in sulfur recycling into the deep mantle. Here, we investigated the crystal structure and phase relation of CaSO4 up to ~90 GPa and 2300 K through a series of high-pressure experiments combined with in situ X-ray diffraction. CaSO4 forms three thermodynamically stable polymorphs: anhydrite (stable below 3 GPa), monazite-type phase (stable between 3 and ~13 GPa) and barite-type phase (stable up to at least 93 GPa). Anhydrite to monazite-type phase transition is induced by pressure even at room temperature, while monazite- to barite-type transition requires heating at least to 1500 K at ~20 GPa. The barite-type phase cannot always be quenched from high temperature and is distorted to metastable AgMnO4-type structure or another modified barite structure depending on pressure. We obtained the pressure-volume data and density of anhydrite, monazite- and barite-type phases and found that their densities are lower than those calculated from the PREM model in the studied P-T conditions. This suggests that CaSO4 is gravitationally unstable in the mantle and fluid/melt phase into which sulfur dissolves and/or sulfate-sulfide speciation may play a major role in the sulfur recycling into the deep Earth.
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The effect of CO2 on the water-saturated solidus of K-poor peridotite between 4 and 6 GPa
NASA Astrophysics Data System (ADS)
Dvir, Omri; Kessel, Ronit
2017-06-01
The effect of various amounts of CO2 on the solidus of H2O-CO2-bearing peridotite was examined by determining the composition of H2O-CO2-bearing fluids and melts in equilibrium with garnet peridotite at 4-6 GPa and 900-1100 °C. Two capsules were placed in a rocking multi-anvil apparatus in each experiment. Both capsules contained a fertile peridotite with 10 wt% H2O, one with 1 (CLZ1) and the other with 5 wt% CO2 (CLZ5). In both capsules a diamond trap was placed on one end of the capsule as a fluid/melt trap. The H2O and CO2 content in the fluid or melt trapped in between the diamonds were measured using the quartz-tube-system technique by releasing the volatiles through infrared gas analyzer. The total dissolved solids in these phases were determined using the cryogenic laser-ablation - inductive couple plasma - mass spectrometry technique. The residual lherzolite consists of olivine, orthopyroxene, ±clinopyroxene, garnet, and ±magnesite as carbonate phase. The solidus of CLZ1 peridotite was located between 900 and 1000 °C at 4 GPa and between 1000 and 1100 °C at 5 and 6 GPa. CLZ5 peridotite melts below 900 °C at 4 GPa and between 900 and 1000 °C at 5 and 6 GPa. The results demonstrate a decrease in melting temperature of hydrous peridotite at pressures between 4 and 6 GPa with increasing amount of CO2. The H2O-CO2-bearing fluids found in this study at 900-1000 °C are similar in composition to low-Mg carbonatitic to silicic high-density fluids found in fluid inclusions in diamonds. With increasing temperature, the melts approach type II kimberlites. We propose that H2O-CO2-induced partial melting of metasomatized garnet lherzolite at 4-6 GPa is a possible origin for group II kimberlites.
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Time-resolved light emission of a, c, and r-cut sapphires shock-compressed to 65 GPa
NASA Astrophysics Data System (ADS)
Liu, Q. C.; Zhou, X. M.
2018-04-01
To investigate light emission and dynamic deformation behaviors, sapphire (single crystal Al2O3) samples with three crystallographic orientations (a, c, and r-cut) were shock-compressed by the planar impact method, with final stress ranges from 47 to 65 GPa. Emission radiance and velocity versus time profiles were simultaneously measured with a fast pyrometer and a Doppler pin system in each experiment. Wave profile results show anisotropic elastic-plastic transitions, which confirm the literature observations. Under final shock stress of about 52 GPa, lower emission intensity is observed in the r-cut sample, in agreement with the previous report in the literature. When final shock stress increases to 57 GPa and 65 GPa, spectral radiance histories of the r-cut show two stages of distinct features. In the first stage, the emission intensity of r-cut is lower than those of the other two, which agrees with the previous report in the literature. In the second stage, spectral radiance of r-cut increases with time at much higher rate and it finally peaks over those of the a and c-cut. These observations (conversion of intensified emission in the r-cut) may indicate activation of a second slip system and formation of shear bands which are discussed with the resolved shear stress calculations for the slip systems in each of the three cuts under shock compression.
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Evaluation of natural mandibular shape asymmetry: an approach by using elliptical Fourier analysis.
Niño-Sandoval, Tania C; Morantes Ariza, Carlos F; Infante-Contreras, Clementina; Vasconcelos, Belmiro Ce
2018-04-05
The purpose of this study was to demonstrate that asymmetry is a natural occurring phenomenon in the mandibular shape by using elliptical Fourier analysis. 164 digital orthopantomographs from Colombian patients of both sexes aged 18 to 25 years were collected. Curves from left and right hemimandible were digitized. An elliptical Fourier analysis was performed with 20 harmonics. In the general sexual dimorphism a principal component analysis (PCA) and a hotelling T 2 from the multivariate warp space were employed. Exploratory analysis of general asymmetry and sexual dimorphism by side was made with a Procrustes Fit. A non-parametric multivariate analysis of variance (MANOVA) was applied to assess differentiation of skeletal classes of each hemimandible, and a Procrustes analysis of variance (ANOVA) was applied to search any relation between skeletal class and side in both sexes. Significant values were found in general asymmetry, general sexual dimorphism, in dimorphism by side (p < 0.0001), asymmetry by sex, and differences between Class I, II, and III (p < 0.005). However, a relation of skeletal classes and side was not found. The mandibular asymmetry by shape is present in all patients and should not be articulated exclusively to pathological processes, therefore, along with sexual dimorphism and differences between skeletal classes must be taken into account for improving mandibular prediction systems.
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Grade Point Average: Report of the GPA Pilot Project 2013-14
ERIC Educational Resources Information Center
Higher Education Academy, 2015
2015-01-01
This report is published as the result of a range of investigations and debates involving many universities and colleges and a series of meetings, presentations, discussions and consultations. Interest in a grade point average (GPA) system was originally initiated by a group of interested universities, progressing to the systematic investigation…
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Briggs, R; Gorman, M G; Coleman, A L; McWilliams, R S; McBride, E E; McGonegle, D; Wark, J S; Peacock, L; Rothman, S; Macleod, S G; Bolme, C A; Gleason, A E; Collins, G W; Eggert, J H; Fratanduono, D E; Smith, R F; Galtier, E; Granados, E; Lee, H J; Nagler, B; Nam, I; Xing, Z; McMahon, M I
2017-01-13
Using x-ray diffraction at the Linac Coherent Light Source x-ray free-electron laser, we have determined simultaneously and self-consistently the phase transitions and equation of state (EOS) of the lightest transition metal, scandium, under shock compression. On compression scandium undergoes a structural phase transition between 32 and 35 GPa to the same bcc structure seen at high temperatures at ambient pressures, and then a further transition at 46 GPa to the incommensurate host-guest polymorph found above 21 GPa in static compression at room temperature. Shock melting of the host-guest phase is observed between 53 and 72 GPa with the disappearance of Bragg scattering and the growth of a broad asymmetric diffraction peak from the high-density liquid.
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Flexibility of the Cu,Zn superoxide dismutase structure investigated at 0.57 GPa.
Ascone, Isabella; Savino, Carmelinda; Kahn, Richard; Fourme, Roger
2010-06-01
The 2 A resolution crystal structure of bovine erythrocyte Cu,Zn superoxide dismutase (CuZnSOD) has been determined by X-ray diffraction at high pressure (0.57 GPa) and room temperature. At 0.57 GPa the secondary, tertiary and quaternary structures are similar to other previously determined bovine erythrocyte CuZnSOD structures. Nevertheless, pressure has a localized impact on the atomic coordinates of C(alpha) atoms and on side chains. The compression of the crystal and of the protein backbone is anisotropic. This anisotropy is discussed, taking into account intermolecular contacts and protein conformation. Pressure perturbation highlights the more flexible zones in the protein such as the electrostatic loop. At 0.57 GPa, a global shift of the dimetallic sites in both subunits and changes in the oxidation state of Cu were observed. The flexibility of the electrostatic loop may be useful for the interaction of different metal carriers in the copper-uptake process, whereas the flexibility of the metal sites involved in the activity of the protein could contribute to explaining the ubiquitous character of CuZnSODs, which are found in organisms living in very different conditions, including the deep-sea environment. This work illustrates the potential of combining X-ray crystallography with high pressure to promote and stabilize higher energy conformational substates.
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Moore, Paul A; Shah, Kalpana; Yang, Yinhua; Alderson, Ralph; Roberts, Penny; Long, Vatana; Liu, Daorong; Li, Jonathan C; Burke, Steve; Ciccarone, Valentina; Li, Hua; Fieger, Claudia B; Hooley, Jeff; Easton, Ann; Licea, Monica; Gorlatov, Sergey; King, Kathleen L; Young, Peter; Adami, Arash; Loo, Deryk; Chichili, Gurunadh R; Liu, Liqin; Smith, Douglas H; Brown, Jennifer G; Chen, Francine Z; Koenig, Scott; Mather, Jennie; Bonvini, Ezio; Johnson, Syd
2018-06-04
We have developed MGD007 (anti-glycoprotein A33 x anti-CD3), a DART® protein designed to redirect T-cells to target gpA33 expressing colon cancer. The gpA33 target was selected based on an antibody-based screen to identify cancer antigens universally expressed in both primary and metastatic CRC specimens, including putative cancer stem cell populations. MGD007 displays the anticipated bispecific binding properties and mediates potent lysis of gpA33-positive cancer cell lines, including models of colorectal cancer stem cells, through recruitment of T-cells. Xenograft studies showed tumor growth inhibition at doses as low as 4 µg/kg. Both CD8 and CD4 T cells mediated lysis of gpA33-expressing tumor cells, with activity accompanied by increases in granzyme and perforin. Notably, suppressive T-cell populations could also be leveraged to mediate lysis of gpA33 expressing tumor cells. Concomitant with CTL activity, both T-cell activation and expansion are observed in a gpA33-dependent manner. No cytokine activation was observed with human PBMC alone, consistent with the absence of gpA33 expression on peripheral blood cell populations. Following prolonged exposure to MGD007 and gpA33 positive tumor cells, T cells express PD 1 and LAG-3 and acquire a memory phenotype but retain ability to support potent cell killing. In cynomolgus monkeys, 4 weekly doses of 100 µg/kg were well tolerated, with prolonged PK consistent with that of an Fc-containing molecule. Taken together MGD007 displays potent activity against colorectal cancer cells consistent with a mechanism of action endowed in its design and support further investigation of MGD007 as a potential novel therapeutic treatment for colorectal cancer. Copyright ©2018, American Association for Cancer Research.
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Schwartz, Joseph A; Beaver, Kevin M
2015-05-01
Academic achievement has been found to have a pervasive and substantial impact on a wide range of developmental outcomes and has also been implicated in the critical transition from adolescence into early adulthood. Previous research has revealed that self-reported grades tend to diverge from official transcript grade point average (GPA) scores, with students being more likely to report inflated scores. Making use of a sample of monozygotic twin (N = 282 pairs), dizygotic twin (N = 441 pairs), and full sibling (N = 1,757 pairs) pairs from the National Longitudinal Study of Adolescent Health (Add Health; 65 % White; 50 % male; mean age = 16.14), the current study is the first to investigate the role that genetic and environmental factors play in misreporting grade information. A comparison between self-reported GPA (mean score of 2.86) and official transcript GPA scores (mean score of 2.44) revealed that self-reported scores were approximately one-half letter grade greater than official scores. Liability threshold models revealed that additive genetic influences explained between 40 and 63 % of the variance in reporting inflated grades and correctly reporting GPA, with the remaining variance explained by the nonshared environment. Conversely, 100 % of the variance in reporting deflated grade information was explained by nonshared environmental influences. In an effort to identify specific nonshared environmental influences on reporting accuracy, multivariate models that adequately control for genetic influences were estimated and revealed that siblings with lower transcript GPA scores were significantly less likely to correctly report their GPA and significantly more likely to report inflated GPA scores. Additional analyses revealed that verbal IQ and self-control were not significantly associated with self-reported GPA accuracy after controlling for genetic influences. These findings indicate that previous studies that implicate verbal IQ and self
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Pressure generation to 65 GPa in a Kawai-type multi-anvil apparatus with tungsten carbide anvils
NASA Astrophysics Data System (ADS)
Ishii, Takayuki; Yamazaki, Daisuke; Tsujino, Noriyoshi; Xu, Fang; Liu, Zhaodong; Kawazoe, Takaaki; Yamamoto, Takafumi; Druzhbin, Dmitry; Wang, Lin; Higo, Yuji; Tange, Yoshinori; Yoshino, Takashi; Katsura, Tomoo
2017-10-01
We have expanded the pressure ranges at room and high temperatures generated in a Kawai-type multi-anvil apparatus (KMA) using tungsten carbide (WC) anvils with a high hardness of Hv = 2700 and a Young's modulus of 660 GPa. At room temperature, a pressure of 64 GPa, which is the highest pressure generated with KMA using WC anvils in the world, was achieved using 1°-tapered anvils with a 1.5-mm truncation. Pressures of 48-50 GPa were generated at high temperatures of 1600-2000 K, which are also higher than previously achieved. Tapered anvils make wide anvil gaps enabling efficient X-ray diffraction. The present pressure generation technique can be used for studying the upper part of the Earth's lower mantle down to 1200 km depth without sintered diamond anvils.
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Briggs, R.; Gorman, M. G.; Coleman, A. L.; ...
2017-01-09
Using x-ray diffraction at the Linac Coherent Light Source x-ray free-electron laser, we have determined simultaneously and self-consistently the phase transitions and equation of state (EOS) of the lightest transition metal, scandium, under shock compression. On compression scandium undergoes a structural phase transition between 32 and 35 GPa to the same bcc structure seen at high temperatures at ambient pressures, and then a further transition at 46 GPa to the incommensurate host-guest polymorph found above 21 GPa in static compression at room temperature. Furthermore, shock melting of the host-guest phase is observed between 53 and 72 GPa with the disappearancemore » of Bragg scattering and the growth of a broad asymmetric diffraction peak from the high-density liquid.« less
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Emergent high-spin state above 7 GPa in superconducting FeSe
NASA Astrophysics Data System (ADS)
Lebert, B. W.; Balédent, V.; Toulemonde, P.; Ablett, J. M.; Rueff, J.-P.
2018-05-01
The local electronic and magnetic properties of superconducting FeSe have been investigated by K β x-ray emission and simultaneous x-ray absorption spectroscopy (XAS) at the Fe K edge at high pressure and low temperature. Our results indicate a sluggish decrease of the local Fe spin moment under pressure up to 7 GPa, in line with previous reports, followed by a sudden increase at higher pressure. The magnetic surge is preceded by an abrupt change of the Fe local structure as observed by the decrease of the XAS preedge region intensity and corroborated by ab initio simulations. This pressure corresponds to a structural transition from the C m m a form to the denser P b n m form with octahedral coordination of iron. Finally, the near-edge region of the XAS spectra shows a change before this transition at 5 GPa, corresponding well with the onset pressure of the sudden enhancement of Tc. Our results emphasize the delicate interplay between structural, magnetic, and superconducting properties in FeSe under pressure.
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NASA Astrophysics Data System (ADS)
Asanuma, Hidetoshi; Ohtani, Eiji; Sakai, Takeshi; Terasaki, Hidenori; Kamada, Seiji; Hirao, Naohisa; Ohishi, Yasuo
2011-10-01
The pressure-volume equations of state of iron-nickel-silicon alloy Fe 0.83Ni 0.09Si 0.08 (Fe-9.8 wt.% Ni-4.0 wt.% Si) and iron-silicon alloy Fe 0.93Si 0.07 (Fe-3.4 wt.% Si) have been investigated up to 374 GPa and 252 GPa, respectively. The present compression data covered pressures of the Earth's core. We confirmed that both Fe 0.83Ni 0.09Si 0.08 and Fe 0.93Si 0.07 alloys remain in the hexagonal close packed structure at all pressures studied. We obtained the density of these alloys at the pressure of the inner core boundary (ICB), 330 GPa at 300 K by fitting the compression data to the third order Birch-Murnaghan equation of state. Using these density values combined with the previous data for hcp-Fe, hcp-Fe 0.8Ni 0.2, and hcp-Fe 0.84Si 0.16 alloys and comparing with the density of the PREM inner core, we estimated the Ni and Si contents of the inner core. The Si content of the inner core estimated here is slightly greater than that estimated previously based on the sound velocity measurement of the hcp-Fe-Ni-Si alloy at high pressure.
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Lim, J.; Fabbris, G.; Haskel, D.; ...
2015-05-26
In previous studies the pressure dependence of the magnetic ordering temperature T o of Dy was found to exhibit a sharp increase above its volume collapse pressure of 73 GPa, appearing to reach temperatures well above ambient at 157 GPa. In a search for a second such lanthanide, electrical resistivity measurements were carried out on neighboring Tb to 141 GPa over the temperature range 3.8 - 295 K. Below Tb’s volume collapse pressure of 53 GPa, the pressure dependence T o(P) mirrors that of both Dy and Gd. However, at higher pressures T o(P) for Tb becomes highly anomalous. Thismore » result, together with the very strong suppression of superconductivity by dilute Tb ions in Y, suggests that extreme pressure transports Tb into an unconventional magnetic state with an anomalously high magnetic ordering temperature.« less
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Carpentier, Jean; Grenier, Eric; Esquibet, Magalie; Hamel, Louis-Philippe; Moffett, Peter; Manzanares-Dauleux, Maria J; Kerlan, Marie-Claire
2013-04-19
The Ran GTPase Activating Protein 2 (RanGAP2) was first described as a regulator of mitosis and nucleocytoplasmic trafficking. It was then found to interact with the Coiled-Coil domain of the Rx and GPA2 resistance proteins, which confer resistance to Potato Virus X (PVX) and potato cyst nematode Globodera pallida, respectively. RanGAP2 is thought to mediate recognition of the avirulence protein GP-RBP-1 by GPA2. However, the Gpa2-induced hypersensitive response appears to be relatively weak and Gpa2 is limited in terms of spectrum of efficiency as it is effective against only two nematode populations. While functional and evolutionary analyses of Gp-Rbp-1 and Gpa2 identified key residues in both the resistance and avirulence proteins that are involved in recognition determination, whether variation in RanGAP2 also plays a role in pathogen recognition has not been investigated. We amplified a total of 147 RanGAP2 sequences from 55 accessions belonging to 18 different di-and tetraploid Solanum species from the section Petota. Among the newly identified sequences, 133 haplotypes were obtained and 19.1% of the nucleotide sites were found to be polymorphic. The observed intra-specific nucleotide diversity ranges from 0.1 to 1.3%. Analysis of the selection pressures acting on RanGAP2 suggests that this gene evolved mainly under purifying selection. Nonetheless, we identified polymorphic positions in the protein sequence at the intra-specific level, which could modulate the activity of RanGAP2. Two polymorphic sites and a three amino-acid deletion in RanGAP2 were found to affect the timing and intensity of the Gpa2-induced hypersensitive response to avirulent GP-RBP-1 variants even though they did not confer any gain of recognition of virulent GP-RBP-1 variants. Our results highlight how a resistance gene co-factor can manage in terms of evolution both an established role as a cell housekeeping gene and an implication in plant parasite interactions. StRanGAP2 gene
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NASA Astrophysics Data System (ADS)
Li, Yi-Lei; Liu, Fu-Sheng; Zhang, Ming-Jian; Ma, Xiao-Juan; Li, Ying-Lei; Zhang, Ji-Chun
2009-03-01
The oscillatory damping curve of a shock front propagating in iron shocked to 103 GPa is measured by use of two-stage light-gas gun and electric pin techniques. The corresponding effective shear viscosity coefficient is deduced to be about 2000 Pa·s from Miller and Ahrens' formula. The result is consistent with that of Mineev's data at 31GPa, while it is higher by five orders than the predictions based on the static measurements at about 5 GPa and 2000 K and molecular dynamic simulation up to 135-375 GPa and 4300-6000 K, and the discussions are presented.
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The Hugoniot and chemistry of ablator plastic below 100 GPa
Akin, M. C.; Fratanduono, D. E.; Chau, R.
2016-01-25
The equation of state of glow discharge polymer (GDP) was measured to high precision using the two-stage light gas gun at Lawrence Livermore National Laboratory at pressures up to 70 GPa. Both absolute measurements and impedance matching techniques were used to determine the principal and secondary Hugoniots. GDP likely reacts at about 30 GPa, demonstrated by specific emission at 450 nm coupled with changes to the Hugoniot and reshock points. As a result of these reactions, the shock pressure in GDP evolves in time, leading to a possible decrease in pressure as compression increases, or negative compressibility, and causing complexmore » pressure profiles within the plastic. Velocity wave profile variation was observed as a function of position on each shot, suggesting some internal variation of GDP may be present, which would be consistent with previous observations. The complex temporal and possibly structural evolution of GDP under shock compression suggests that calculations of compression and pressure based upon bulk or mean measurements may lead to artificially low pressures and high compressions. Evidence for this includes a large shift in calculating reshock pressures based on the reflected Hugoniot. In conclusion, these changes also suggest other degradation mechanisms for inertial confinement fusion implosions.« less
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NASA Astrophysics Data System (ADS)
Keshav, S.; Gudfinnsson, G. H.
2007-12-01
The carbonate ledge at ~2.0 GPa is a pronounced feature of the carbonated peridotite solidus. At the ledge, where the CO2-bearing phase changes from vapour to carbonate, the melt composition becomes carbonatitic. After this drop, the solidus of carbonated peridotite gradually rises in P-T space, up to at least 12 GPa. Between 14 and 16 GPa, Keshav et al. (2007) reported another drop in the solidus of carbonated peridotite in the model CMS-CO2 system. Similar to the lower-pressure topology, the solidus at higher pressure resumes a positive slope between 16-20 GPa, and seems to flatten between 22 and 26 GPa. Concomitant with this second drop, the melts become extremely calcic (Ca/Ca+Mg, Ca no.-0.62) at 16 and 20 GPa, but attain more magnesio-carbonatitic (Ca no.-0.40) character both at shallower or greater depths than the transition zone. Clearly, the second drop in the carbonated peridotite solidus has tremendous consequences for geological processes in the deep mantle. The other major rock-type presumed to be present in the mantle is eclogite of broadly basaltic composition. Clarifying the solidus topology of carbonated eclogite in model systems over a similar pressure range is also an important task, because the solidus topology affects the fate of subducted carbonate in the deeper mantle. The position of the solidus of carbonated eclogite will address its impact on local or extensive melting (if it occurs), the possible relationship between the carbonated peridotite and carbonated eclogite solidi at these depths (400-600 km), their respective incipient melts, and ultimately the possibility of carbonate survival at these and greater depths. With these issues in mind, we have determined the solidus of model carbonated eclogite in model CMAS- CO2 system between 14 and 20 GPa. At 14 and 16 GPa, the melts are in equilibrium with cpx, majoritic garnet, stishovite, and magnesite. At 20 GPa, the melts are in equilibrium with calcium-perovskite (capv), garnet, stishovite
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Effect of pressure on viscosity of liquid Fe-alloys up to 16 GPa
NASA Astrophysics Data System (ADS)
Terasaki, H.; Ohtani, E.; Suzuki, A.; Nishida, K.; Sakamaki, T.; Shindo, S.; Funakoshi, K.
2005-12-01
Viscosity of liquid Fe-alloy is closely related to a convection behavior of the Earth's liquid outer core and also time scale of planetary core formation. In previous studies, viscosity of liquid Fe-S has been measured up to 7 GPa using X-ray radiography falling sphere method [Terasaki et al. 2001]. However, some technical problems, such as chemical reaction between the metal marker sphere and the Fe-alloy sample and insufficient image recording time for less viscous material, have been suggested. In this study, we have measured the viscosity of Fe-S and Fe-C liquids without those problems by using novel techniques combined with in situ X-ray radiography falling sphere method and extended the pressure range to 16 GPa. Falling sphere viscometry was carried out under high pressure and temperature using high speed CCD camera with 1500 ton Kawai-type multi-anvil device at BL04B1, SPring-8 in Japan. Starting compositions of Fe-alloy were Fe78S22 and Fe86C14 which correspond to near eutectic compositions at the experimental pressures. Viscosity marker sphere, which was made of Re or Pt, was coated by alumina in order to prevent the reaction between the sphere and the Fe-alloy sample. Falling sphere images were obtained with recording rate of 50 - 125 frame/second. Viscosity of liquid Fe-S was measured up to 16.1 GPa and 1763 K. Measured viscosity coefficients were in the range of 8.8 - 9.2 mPa-s which indicates that the activation volume of viscous flow is approximately a half of the previous estimations (1.5 cm3/mol). Viscosity of liquid Fe-C was measured up to 5 GPa and 1843 K. Viscosity coefficients are 4.7 - 4.9 mPa-s. Activation volume of Fe-C liquid is estimated to be 0.8 cm3/mol. This pressure dependence is consistent with the result of Lucas (1964) measured at ambient pressure. Consequently, viscosity of Fe-alloy liquids are likely to stay small in the Earth's interior and there is no large difference in viscosity coefficient and activation volume between Fe
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Geometric morphometric analysis of mandibular shape diversity in Pan.
Robinson, Chris
2012-07-01
The aim of this research is to determine whether geometric morphometric (GM) techniques can provide insights into how the shape of the mandibular corpus differs between bonobos and chimpanzees and to explore the potential implications of those results for our understanding of hominin evolution. We focused on this region of the mandible because of the relative frequency with which it has been recovered in the hominin fossil record. In addition, no previous study had explored in-depth three-dimensional (3D) mandibular corpus shape differences between adults of the two Pan species using geometric morphometrics. GM methods enable researchers to quantitatively analyze and visualize 3D shape changes in skeletal elements and provide an important compliment to traditional two-dimensional analyses. Eighteen mandibular landmarks were collected using a Microscribe 3DX portable digitizer. Specimen configurations were superimposed using Generalized Procrustes analysis and the projections of the fitted coordinates to tangent space were analyzed using multivariate statistics. The size-adjusted corpus shapes of Pan paniscus and Pan troglodytes could be assigned to species with approximately 93% accuracy and the Procrustes distance between the two species was significant. Analyses of the residuals from a multivariate linear regression of the data on centroid size suggested that much of the shape difference between the species is size-related. Chimpanzee subspecies and a small sample of Australopithecus specimens could be correctly identified to taxon, at best, only 75% of the time, although the Procrustes distances between these taxa were significant. The shape of the mandibular symphysis was identified as especially useful in differentiating Pan species from one another. This suggests that this region of the mandible has the potential to be informative for taxonomic analyses of fossil hominoids, including hominins. The results also have implications for phylogenetic hypotheses of
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X-ray Diffraction Study of Molybdenum to 900 GPa
NASA Astrophysics Data System (ADS)
Wang, J.; Coppari, F.; Smith, R.; Eggert, J.; Boehly, T.; Collins, G. W.; Duffy, T. S.
2013-12-01
Molybdenum (Mo) is a transition metal that is important as a high-pressure standard. Its equation of state, structure, and melting behavior have been explored extensively in both experimental and theoretical studies. Melting data up to the Mbar pressure region from static compression experiments in the diamond anvil cell [Errandonea et al. 2004] are inconsistent with shock wave sound velocity measurements [Hixson et al., 1989]. There are also conflicting reports as to whether body-centered cubic (BCC) Mo transforms to a face-centered cubic (FCC), hexagonal close packed (HCP) or double hexagonal close packed (DHCP) structure at either high pressure or high pressure and temperature conditions [Belonoshko et al. 2008, Mikhaylushkin et al., 2008 and Cazorla et al., 2008]. Recently, a phase transition from BCC to the DHCP phase at 660 GPa and 0 K was predicted using the particle swam optimization (PSO) method (Wang et al, 2013). Here we report an x-ray diffraction study of dynamically compressed molybdenum. Experiments were conducted using the Omega laser at the Laboratory for Laser Energetics at the University of Rochester. Mo targets were either ramp or shock compressed using a laser drive. In ramp loading, the sample is compressed sufficiently slowly that a shock wave does not form. This results in lower temperatures, keeping the sample in the solid state to higher pressures. X-ray diffraction measurements were performed using quasi-monochromatic x-rays from a highly ionized He-α Cu source and image plate detectors. Upon ramp compression, we found no evidence of phase transition in solid Mo up to 900 GPa. The observed peaks can be assigned to the (110) and (200) or (220) reflections of BCC Mo up to the highest pressure, indicating that Mo does not melt under ramp loading to maximum pressure reached. Under shock loading, we did not observe any evidence for the solid-solid phase transformation around 210 GPa as reported in previous work (Hixson et al, 1989). The BCC
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Sohn, Seok Su; Song, Hyejin; Jo, Min Chul; Song, Taejin; Kim, Hyoung Seop; Lee, Sunghak
2017-04-28
Needs for steel designs of ultra-high strength and excellent ductility have been an important issue in worldwide automotive industries to achieve energy conservation, improvement of safety, and crashworthiness qualities. Because of various drawbacks in existing 1.5-GPa-grade steels, new development of formable cold-rolled ultra-high-strength steels is essentially needed. Here we show a plausible method to achieve ultra-high strengths of 1.0~1.5 GPa together with excellent ductility above 50% by actively utilizing non-recrystallization region and TRansformation-Induced Plasticity (TRIP) mechanism in a cold-rolled and annealed Fe-Mn-Al-C-based steel. We adopt a duplex microstructure composed of austenite and ultra-fine ferrite in order to overcome low-yield-strength characteristics of austenite. Persistent elongation up to 50% as well as ultra-high yield strength over 1.4 GPa are attributed to well-balanced mechanical stability of non-crystallized austenite with critical strain for TRIP. Our results demonstrate how the non-recrystallized austenite can be a metamorphosis in 1.5-GPa-grade steel sheet design.
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NASA Astrophysics Data System (ADS)
Bezaeva, Natalia S.; Demory, François; Rochette, Pierre; Sadykov, Ravil A.; Gattacceca, Jérôme; Gabriel, Thomas; Quesnel, Yoann
2015-12-01
We present new experimental data on the dependence of the Morin transition temperature (TM) on hydrostatic pressure up to 1.61 GPa, obtained on a well-characterized multidomain hematite-bearing sample from a banded iron formation. We used a nonmagnetic high-pressure cell for pressure application and a Superconducting Quantum Interference Device magnetometer to measure the isothermal remanent magnetization (IRM) under pressure on warming from 243 K to room temperature (T0). IRM imparted at T0 under pressure in 270 mT magnetic field (IRM270mT) is not recovered after a cooling-warming cycle. Memory effect under pressure was quantified as IRM recovery decrease of 10%/GPa. TM, determined on warming, reaches T0 under hydrostatic pressure 1.38-1.61 GPa. The pressure dependence of TM up to 1.61 GPa is positive and essentially linear with a slope dTM/dP = (25 ± 2) K/GPa. This estimate is more precise than previous ones and allows quantifying the effect of a pressure wave on the upper crust magnetization, with special emphasis on Mars.
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A study of tantalum pentoxide Ta 2O 5 structures up to 28 GPa
Stavrou, Elissaios; Zaug, Joseph M.; Bastea, Sorin; ...
2017-05-02
In this study, tantalum pentoxide Ta 2O 5 with the orthorhombic L-Ta 2O 5 structure has been experimentally studied up to 28.3 GPa (at ambient temperature) using synchrotron angle-dispersive powder X-ray diffraction (XRD). The ambient pressure phase remains stable up to 25 GPa where with increased pressure a crystalline to amorphous phase transition occurs. A detailed equation of state (EOS), including pressure dependent lattice parameters, is reported. The results of this study were compared with a previous high-pressure XRD study by Li et al. A clear discrepancy between the ambient-pressure crystal structures and, consequently, the reported EOSs between the twomore » studies was revealed. Finally, he origin of this discrepancy is attributed to two different crystal structures used to index the XRD patterns.« less
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First-Year College Students' Time Use: Relations With Self-Regulation and GPA
ERIC Educational Resources Information Center
Thibodeaux, Jordan; Deutsch, Aaron; Kitsantas, Anastasia; Winsler, Adam
2017-01-01
How students manage their time is critical for academic performance and is an important component of self-regulated learning. The purpose of the present study was to examine relationships among first-year college students' (N = 589) time use, academic self-regulation, and target and actual grade point average (GPA) at three time points. Findings…
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Brazhkin, V. V., E-mail: brazhkin@hppi.troitsk.ru; Bychkov, E.; Tsiok, O. B.
2016-08-15
The volumes of glassy germanium chalcogenides GeSe{sub 2}, GeS{sub 2}, Ge{sub 17}Se{sub 83}, and Ge{sub 8}Se{sub 92} are precisely measured at a hydrostatic pressure up to 8.5 GPa. The stoichiometric GeSe{sub 2} and GeS{sub 2} glasses exhibit elastic behavior in the pressure range up to 3 GPa, and their bulk modulus decreases at pressures higher than 2–2.5 GPa. At higher pressures, inelastic relaxation processes begin and their intensity is proportional to the logarithm of time. The relaxation rate for the GeSe{sub 2} glasses has a pronounced maximum at 3.5–4.5 GPa, which indicates the existence of several parallel structural transformation mechanisms.more » The nonstoichiometric glasses exhibit a diffuse transformation and inelastic behavior at pressures above 1–2 GPa. The maximum relaxation rate in these glasses is significantly lower than that in the stoichiometric GeSe{sub 2} glasses. All glasses are characterized by the “loss of memory” of history: after relaxation at a fixed pressure, the further increase in the pressure returns the volume to the compression curve obtained without a stop for relaxation. After pressure release, the residual densification in the stoichiometric glasses is about 7% and that in the Ge{sub 17}Se{sub 83} glasses is 1.5%. The volume of the Ge{sub 8}Se{sub 92} glass returns to its initial value within the limits of experimental error. As the pressure decreases, the effective bulk moduli of the Ge{sub 17}Se{sub 83} and Ge{sub 8}Se{sub 92} glasses coincide with the moduli after isobaric relaxation at the stage of increasing pressure, and the bulk modulus of the stoichiometric GeSe{sub 2} glass upon decreasing pressure noticeably exceeds the bulk modulus after isobaric relaxation at the stage of increasing pressure. Along with the reported data, our results can be used to draw conclusions regarding the diffuse transformations in glassy germanium chalcogenides during compression.« less
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NASA Astrophysics Data System (ADS)
Vasiukov, D. M.; Ismailova, L.; Kupenko, I.; Cerantola, V.; Sinmyo, R.; Glazyrin, K.; McCammon, C.; Chumakov, A. I.; Dubrovinsky, L.; Dubrovinskaia, N.
2018-05-01
High-pressure experimental data on sound velocities of garnets are used for interpretation of seismological data related to the Earth's upper mantle and the mantle transition zone. We have carried out a Nuclear Inelastic Scattering study of iron-silicate garnet with skiagite (77 mol%)-iron-majorite composition in a diamond anvil cell up to 56 GPa at room temperature. The determined sound velocities are considerably lower than sound velocities of a number of silicate garnet end-members, such as grossular, pyrope, Mg-majorite, andradite, and almandine. The obtained sound velocities have the following pressure dependencies: V p [km/s] = 7.43(9) + 0.039(4) × P [GPa] and V s [km/s] = 3.56(12) + 0.012(6) × P [GPa]. We estimated sound velocities of pure skiagite and khoharite, and conclude that the presence of the iron-majorite component in skiagite strongly decreases V s . We analysed the influence of Fe3+ on sound velocities of garnet solid solution relevant to the mantle transition zone and consider that it may reduce sound velocities up to 1% relative to compositions with only Fe2+ in the cubic site.
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The Principal Hugoniot of Forsterite to 950 GPa
NASA Astrophysics Data System (ADS)
Root, Seth; Townsend, Joshua P.; Davies, Erik; Lemke, Raymond W.; Bliss, David E.; Fratanduono, Dayne E.; Kraus, Richard G.; Millot, Marius; Spaulding, Dylan K.; Shulenburger, Luke; Stewart, Sarah T.; Jacobsen, Stein B.
2018-05-01
Forsterite (Mg2SiO4) single crystals were shock compressed to pressures between 200 and 950 GPa using independent plate-impact steady shocks and laser-driven decaying shock compression experiments. Additionally, we performed density functional theory-based molecular dynamics to aid interpretation of the experimental data and to investigate possible phase transformations and phase separations along the Hugoniot. We show that the experimentally obtained Hugoniot cannot distinguish between a pure liquid Mg2SiO4 and an assemblage of solid MgO plus liquid magnesium silicate. The measured reflectivity is nonzero and increases with pressure, which implies that the liquid is a poor electrical conductor at low pressures and that the conductivity increases with pressure.
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ERIC Educational Resources Information Center
Kadhi, T.; Rudley, D.; Holley, D.; Krishna, K.; Ogolla, C.; Rene, E.; Green, T.
2010-01-01
The following report of descriptive statistics addresses the attendance of the 2012 class and the average Actual and Predicted 1L Grade Point Averages (GPAs). Correlational and Inferential statistics are also run on the variables of Attendance (Y/N), Attendance Number of Times, Actual GPA, and Predictive GPA (Predictive GPA is defined as the Index…
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NASA Astrophysics Data System (ADS)
Burchell, M. J.; Harriss, K. H.; Price, M. C.; Yolland, L.
2017-07-01
Previously it has been shown that diatom fossils embedded in ice could survive impacts at speeds of up to 5 km s-1 and peak shock pressures up to 12 GPa. Here we confirm these results using a different technique, with diatoms carried in liquid water suspensions at impact speeds of 2-6 km s-1. These correspond to peak shock pressures of 3.8-19.8 GPa. We also report on the results of similar experiments using forams, at impact speeds of 4.67 km s-1 (when carried in water) and 4.73 km s-1 (when carried in ice), corresponding to peak shock pressures of 11.6 and 13.1 GPa respectively. In all cases we again find survival of recognisable fragments, with mean fragment size of order 20-25 μm. We compare our results to the peak shock pressures that ejecta from giant impacts on the Earth would experience if it subsequently impacted the Moon. We find that 98% of impacts of terrestrial ejecta on the Moon would have experienced peak pressures less than 20 GPa if the ejecta were a soft rock (sandstone). This falls to 82% of meteorites if the ejecta were a hard rock (granite). This assumes impacts on a solid lunar surface. If we approximate the surface as a loose regolith, over 99% of the impacts involve peak shock pressures below 20 GPa. Either way, the results show that a significant fraction of terrestrial meteorites impacting the Moon will do so with peak shock pressures which in our experiments permit the survival of recognisable fossil fragments.
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Raman spectroscopy and melting of nitrogen between 290 and 900 K and 2. 3 and 18 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zinn, A.S.; Schiferl, D.; Nicol, M.F.
1987-07-15
Raman spectroscopy was used to study the melting of nitrogen from 290 to 900 K at pressures from 2.3 to 18 GPa. This work, which extends the melting by a factor of 9 over previously published results was made possible by new developments in high-temperature diamond-anvil cells. The ..beta../delta phase boundary was also determined, and the ..beta..--delta--fluid triple point was found to be at 578 +- 10 K and 9.9 +- 0.5 GPa. The Raman frequencies of the vibron in fluid N/sub 2/ and the ..nu../sub 2/ vibron in delta-N/sub 2/ were found to have the same pressure dependence andmore » be independent of temperature to a good approximation. A temperature-independent pressure scale, useful to at least 900 K is approximated by P/GPa = 0.4242 ..nu../cm/sup -1/ -987.8, where ..nu.. is the frequency of either the ..nu../sub 2/ vibron in delta-N/sub 2/ or the vibron in fluid-N/sub 2/.« less
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Remanent magnetization and coercivity of rocks under hydrostatic pressure up to 1.4 GPa
NASA Astrophysics Data System (ADS)
Demory, F.; Rochette, P.; Gattacceca, J.; Gabriel, T.; Bezaeva, N. S.
2013-08-01
We designed an Isothermal Remanent Magnetization (IRM) acquisition system based on permanent magnets and sized to accommodate an amagnetic hydrostatic pressure cell. This pressure cell fits in a superconducting rock magnetometer, allowing for the measurement of remanent magnetization of pressurized samples. With this system, we determined the coercivity of remanence (Bcr) at different hydrostatic pressures up to 1.4 GPa for rock and dispersed mineral samples with various magnetic mineralogy and domain state. IRM and Bcr are nearly identical before compression and after decompression, indicating no permanent changes in the magnetic properties during pressure cycling. Hydrostatic pressure up to 1.4 GPa does not significantly increases IRM under pressure except for multidomain pyrrhotite and magnetite which show an increase of about 40%. Relative increase of Bcr under pressure is mild, except for a near single domain titanomagnetite where Bcr doubles.
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The system Na2CO3-CaCO3 at 3 GPa
NASA Astrophysics Data System (ADS)
Podborodnikov, Ivan V.; Shatskiy, Anton; Arefiev, Anton V.; Rashchenko, Sergey V.; Chanyshev, Artem D.; Litasov, Konstantin D.
2018-04-01
It was suggested that alkali-alkaline earth carbonates may have a substantial role in petrological processes relevant to metasomatism and melting of the Earth's mantle. Because natrite, Na2CO3, Na-Ca carbonate (shortite and/or nyerereite), and calcite, CaCO3, have been recently reported from xenoliths of shallow mantle (110-115 km) origin, we performed experiments on phase relations in the system Na2CO3-CaCO3 at 3 GPa and 800-1300 °C. We found that the system has one intermediate compound, Na2Ca3(CO3)4, at 800 °C, and two intermediate compounds, Na2Ca(CO3)2 and Na2Ca3(CO3)4, at 850 °C. CaCO3 crystals recovered from experiments at 950 and 1000 °C are aragonite and calcite, respectively. Maximum solid solution of CaCO3 in Na2CO3 is 20 mol% at 850 °C. The Na-carbonate-Na2Ca(CO3)2 eutectic locates near 860 °C and 56 mol% Na2CO3. Na2Ca(CO3)2 melts incongruently near 880 °C to produce Na2Ca3(CO3)4 and a liquid containing about 51 mol% Na2CO3. Na2Ca3(CO3)4 disappears above 1000 °C via incongruent melting to calcite and a liquid containing about 43 mol% Na2CO3. At 1050 °C, the liquid, coexisting with Na-carbonate, contains 87 mol% Na2CO3. Na-carbonate remains solid up to 1150 °C and melts at 1200 °C. The Na2CO3 content in the liquid coexisting with calcite decreases to 15 mol% as temperature increases to 1300 °C. Considering the present and previous data, a range of the intermediate compounds on the liquidus of the Na2CO3-CaCO3 join changes as pressure increases in the following sequence: Na2Ca(CO3)2 (0.1 GPa) → Na2Ca(CO3)2, Na2Ca3(CO3)4 (3 GPa) → Na4Ca(CO3)3, Na2Ca3(CO3)4 (6 GPa). Thus, the Na2Ca(CO3)2 nyerereite stability field extends to the shallow mantle pressures. Consequently, findings of nyerereite among daughter phases in the melt inclusions in olivine from the sheared garnet peridotites are consistent with their mantle origin.
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Code of Federal Regulations, 2013 CFR
2013-07-01
... produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? 80.540 Section 80.540... Marine Fuel Geographic Phase-in Provisions § 80.540 How may a refiner be approved to produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? (a) A refiner that has been approved by EPA...
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Code of Federal Regulations, 2014 CFR
2014-07-01
... produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? 80.540 Section 80.540... Marine Fuel Geographic Phase-in Provisions § 80.540 How may a refiner be approved to produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? (a) A refiner that has been approved by EPA...
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Code of Federal Regulations, 2011 CFR
2011-07-01
... produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? 80.540 Section 80.540... Marine Fuel Geographic Phase-in Provisions § 80.540 How may a refiner be approved to produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? (a) A refiner that has been approved by EPA...
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Code of Federal Regulations, 2010 CFR
2010-07-01
... produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? 80.540 Section 80.540... Marine Fuel Geographic Phase-in Provisions § 80.540 How may a refiner be approved to produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? (a) A refiner that has been approved by EPA...
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Code of Federal Regulations, 2012 CFR
2012-07-01
... produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? 80.540 Section 80.540... Marine Fuel Geographic Phase-in Provisions § 80.540 How may a refiner be approved to produce gasoline under the GPA gasoline sulfur standards in 2007 and 2008? (a) A refiner that has been approved by EPA...
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Paulos, Kátia; Rodrigues, Sandra; Oliveira, António Filipe; Leite, Ana; Pereira, Etelvina; Teixeira, Alfredo
2015-07-01
The main objective of this study was the sensory characterization, by a taste and a consumers' panel, of fresh sausages from 140 culled goats and 140 culled ewes. Species and type of preparation effects were studied. All data were previously analyzed by analysis of variance. Taste panel data were analyzed by a Generalized Procrustes Analysis (GPA). Consumers' panel data were analyzed by Preference Mapping. The 1st 2 factors explained 88.22% of total variation in GPA. Different sausages samples were perfectly differentiated by assessors. Goat sausages have been considered harder, more fibrous, and less juicy than sheep sausages. The panelists observed that sheep sausages without paprika had greater intensity of flavor, tasted spicy, and had an off-odor, while goat sausages with paprika were considered sweeter. Consumers' panel did not show any preference for the different types of sausages. This means that all types of sausages can have market opportunity. The present study was a result of a project in co-promotion between 2 breeder associations, an industry unit and a research center. Results indicated that the meat from animals out of quality commercial brands could be useful as processed meat in a product with consumer acceptability. Also these new meat products brought diversity to meat industry to reach new markets and originating 2 new meat brands recorded at INPI (Instituto Nacional da Propriedade Industrial—Natl. Industrial Property Inst.) with the numbers of 489664 and 489662 of National Brands of sheep and goat meat, respectively. © 2015 Institute of Food Technologists®
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A sensitive pressure sensor for diamond anvil cell experiments up to 2 GPa: FluoSpheres[reg
DOE Office of Scientific and Technical Information (OSTI.GOV)
Picard, Aude; Oger, Phil M.; Daniel, Isabelle
2006-08-01
We present an optical pressure sensor suitable for experiments in diamond anvil cell in the 0.1 MPa-2 GPa pressure range, for temperatures between ambient and 323 K. It is based on the pressure-dependent fluorescence spectrum of FluoSpheres[reg], which are commercially available fluorescent microspheres commonly used to measure blood flow in experimental biology. The fluorescence of microspheres is excited by the 514.5 nm line of an Ar{sup +} laser, and the resulting spectrum displays three very intense broad bands at 534, 558, and 598 nm, respectively. The reference wavelength and pressure gauge is that of the first inflection point of themore » spectrum, located at 525.6{+-}0.2 nm at ambient pressure. It is characterized by an instantaneous and large linear pressure shift of 9.93({+-}0.08) nm/GPa. The fluorescence of the FluoSpheres[reg] has been investigated as a function of pressure (0.1-4 GPa), temperature (295-343 K), pH (3-12), salinity, and pressure transmitting medium. These measurements show that, for pressures comprised between 0.1 MPa and 2 GPa, at temperatures not exceeding 323 K, at any pH, in aqueous pressure transmitting media, pressure can be calculated from the wavelength shift of two to three beads, according to the relation P=0.100 ({+-}0.001) {delta}{lambda}{sub i}(P) with {delta}{lambda}{sub i}(P)={lambda}{sub i}(P)-{lambda}{sub i}(0) and {lambda}{sub i}(P) as the wavelength of the first inflection point of the spectrum at the pressure P. This pressure sensor is approximately thirty times more sensitive than the ruby scale and responds instantaneously to pressure variations.« less
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NASA Astrophysics Data System (ADS)
Hermann, Jörg; Troitzsch, Ulrike; Scott, Dean
2016-10-01
The dissociation of dolomite to aragonite + magnesite and the reaction of dolomite + aragonite to Mg-calcite have been experimentally determined by piston cylinder experiments in the range of 650-1000 °C and 2-6.5 GPa. Friction decay within the salt sleeves used as pressure medium was monitored by continuously logging the travel distance of the piston. Piston movement ceased after the first 24 h of the experiment, and all experiments were kept at the steady-state conditions for an additional 24-196 h. The reaction of dolomite to aragonite + magnesite has a positive slope and has been bracketed at 650 °C between 5.1 and 5.8 GPa and at 750 °C between 5.7 and 6.5 GPa. The reaction is sluggish with a 0.6-GPa interval where all three phases coexist. The reaction dolomite + aragonite to Mg-calcite has been determined in 0.5-GPa intervals from 660 °C at 2 GPa to 940 °C at 6.5 GPa. The composition of Mg-calcite at the reaction curve is buffered and changes systematically from X(Ca) of 0.90 at 2 GPa to 0.57 at 6.5 GPa. The solvus between dolomite and Mg-calcite shrinks slightly with increasing pressure, providing evidence for a small negative slope of the critical curve dolomite = Mg-calcite. The degree of disorder in dolomite has been determined in some of the retrieved samples by Rietveld refinement based on X-ray diffraction patterns. The order parameter S decreases gradually from 1 to 0.7 as a function of temperature as the critical curve is approached and then drops dramatically after crossing it. No ordering on quench has been observed. The experimental results permit the construction of a petrogenetic grid for the system dolomite, aragonite, Mg-calcite, and magnesite, which has an invariant point at ~7.5 GPa and 980 °C, representing the maximum pressure stability of dolomite. X(Ca) isopleths of Mg-calcite coexisting with dolomite serve mainly as a thermometer, whereas in the presence of aragonite they are a useful barometer. The experimental results have been
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The Principal Hugoniot of Forsterite to 950 GPa
Root, Seth; Townsend, Joshua P.; Davies, Erik; ...
2018-04-27
Forsterite (Mg 2SiO 4) single crystals were shock compressed to pressures between 200 and 950 GPa using independent plate–impact steady shocks and laser–driven decaying shock compression experiments. Additionally, we performed density functional theory–based molecular dynamics to aid interpretation of the experimental data and to investigate possible phase transformations and phase separations along the Hugoniot. We show that the experimentally obtained Hugoniot cannot distinguish between a pure liquid Mg 2SiO 4 and an assemblage of solid MgO plus liquid magnesium silicate. In conclusion, the measured reflectivity is nonzero and increases with pressure, which implies that the liquid is a poor electricalmore » conductor at low pressures and that the conductivity increases with pressure.« less
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The Principal Hugoniot of Forsterite to 950 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Root, Seth; Townsend, Joshua P.; Davies, Erik
Forsterite (Mg 2SiO 4) single crystals were shock compressed to pressures between 200 and 950 GPa using independent plate–impact steady shocks and laser–driven decaying shock compression experiments. Additionally, we performed density functional theory–based molecular dynamics to aid interpretation of the experimental data and to investigate possible phase transformations and phase separations along the Hugoniot. We show that the experimentally obtained Hugoniot cannot distinguish between a pure liquid Mg 2SiO 4 and an assemblage of solid MgO plus liquid magnesium silicate. In conclusion, the measured reflectivity is nonzero and increases with pressure, which implies that the liquid is a poor electricalmore » conductor at low pressures and that the conductivity increases with pressure.« less
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Stokes-Einstein relation in liquid iron-nickel alloy up to 300 GPa
NASA Astrophysics Data System (ADS)
Cao, Q.-L.; Wang, P.-P.
2017-05-01
Molecular dynamic simulations were applied to investigate the Stokes-Einstein relation (SER) and the Rosenfeld entropy scaling law (ESL) in liquid Fe0.9Ni0.1 over a sufficiently broad range of temperatures (0.70 < T/Tm < 1.85 Tm is melting temperature) and pressures (from 50 GPa to 300 GPa). Our results suggest that the SER and ESL hold well in the normal liquid region and break down in the supercooled region under high-pressure conditions, and the deviation becomes larger with decreasing temperature. In other words, the SER can be used to calculate the viscosity of liquid Earth's outer core from the self-diffusion coefficients of iron/nickel and the ESL can be used to predict the viscosity and diffusion coefficients of liquid Earth's outer core form its structural properties. In addition, the pressure dependence of effective diameters cannot be ignored in the course of using the SER. Moreover, ESL provides a useful, structure-based probe for the validity of SER, while the ratio of the self-diffusion coefficients of the components cannot be used as a probe for the validity of SER.
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X-ray diffraction study of elemental thulium to 86 GPa
NASA Astrophysics Data System (ADS)
Pravica, Michael; Romano, Edward; Quine, Zachary; Pravica, Walter
2006-03-01
We have studied the structures and equation of state of elemental thulium up to 86 GPa in a diamond anvil cell using angular-dispersive x-ray powder diffraction methods at the Advanced Photon Source. This is part of a study of phase transitions in the lanthanide-series metals using cyclohexane as a quasi-hydrostatic medium. We present evidence of a series of phase transitions that appear to follow the anticipated hcp ->Sm-type -> dhcp -> distorted fcc sequence of transitions and show the equation of state derived from the x-ray fit data.
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Structure of siderite FeCO[subscript 3] to 56 GPa and hysteresis of its spin-pairing transition
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lavina, Barbara; Dera, Przemyslaw; Downs, Robert T.
2010-09-17
The structure of siderite, FeCO{sub 3}, was determined to 56 GPa, beyond the spin-pairing transition of its iron d electrons. Fe{sup 2+} in the siderite structure is in the high-spin state at low pressures and transforms to the low-spin (LS) state over a narrow pressure range, 44 to 45 GPa, that is concomitant with a shrinkage of the octahedral bond distance by 4%, and a volume collapse of 10%. The structural rearrangements associated with the electronic transition are nearly isotropic in contrast with other properties of siderite, which mostly are highly anisotropic. Robust refinements of the crystal structure from single-crystalmore » x-ray diffraction data were performed at small pressure intervals in order to accurately evaluate the variation in the interatomic distances and to define the geometry of the carbonate hosting LS-Fe{sup 2+}. Thermal vibrations are remarkably lowered in the LS-Sd as shown by atomic displacement parameters. The formation of like-spin domains at the transition shows a hysteresis of more than 3 GPa, compatible with a strong cooperative contribution of neighboring clusters to the transition.« less
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Code of Federal Regulations, 2010 CFR
2010-07-01
... for a motor vehicle diesel fuel volume baseline for the purpose of extending their gasoline sulfur... a small or GPA refiner apply for a motor vehicle diesel fuel volume baseline for the purpose of... duration of the GPA standards under § 80.540 must apply for a motor vehicle diesel fuel volume baseline by...
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Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Meier, Thomas; Haase, Jürgen
2015-12-15
Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al{sub 2}O{sub 3}), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It ismore » shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.« less
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Interlibrary Loan Article Use and User GPA: Findings and Implications for Library Services
ERIC Educational Resources Information Center
Scott, Mitchell
2014-01-01
A recent institutional study at the University of Wisconsin-Green Bay investigated the academic achievement of interlibrary loan (ILL) users as compared to non-ILL users. While this study provided important local insight into ILL use and the demographics of ILL users (class rank, major), it uncovered a rather minor overall GPA difference, 0.20 GPA…
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NASA Astrophysics Data System (ADS)
Chandra, Usha; Sharma, Pooja; Parthasarathy, G.
2016-12-01
Like bulk, Co1-xFexS2 nanoparticles also display an anomaly at x = 0.5. The borderline contiguous Co1-xFexS2 (x = 0.4 and 0.5) nanoparticles were synthesized with colloidal method and characterized for pyrite structure using various techniques, viz., X-ray diffraction, energy dispersive X-ray analysis (EDAX), S K-edge X-ray absorption near edge spectra, transmission electron microscopy (TEM) and Fourier transformed infra-red spectroscopy. The report presents the effect of high pressure on the borderline compositions using the Mössbauer spectroscopic and electrical resistivity techniques. Magnetic measurements on the system showed drastic lowering of Tc due to nanosize of the particles. With increased pressure, quadrupole splitting showed an expected trend of increase to attain a peak representing a second-order phase transition between 4 and 5 GPa for both the compositions. The pressure coefficient of electrical resistivity varied from -0.02 GPa to -0.06 GPa across transition pressure indicating a sluggish nature of transition. This is the first report of pressure effect on nanosized borderline compositions.
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Ghods, Nayereh; Falahati, Mehraban; Roudbary, Maryam; Farahyar, Shirin; Shamaei, Masoud; Pourabdollah, Mahin; Seif, Farhad
2018-02-03
The virulence genes in invasive aspergillosis (IA) have not been analyzed adequately. The present study was designed to evaluate the expression of gpaB and sidA genes, which are important virulence genes in Aspergillus spp. from bronchoalveolar lavage (BAL) samples. Direct examination and culture on Czapek Agar and Sabouraud Dextrose Agar media were performed for 600 BAL specimens isolated from patients with possible aspergillosis. A Galactomannan ELISA assay was also carried out. The expression levels of the gpaB and sidA genes in isolates were analyzed using quantitative real-time PCR (qRT-PCR). We identified 2 species, including Aspergillus flavus (A. flavus) and Aspergillus fumigatus (A. fumigatus) in 25 positive samples for invasive aspergillosis as validated using GM-ELISA. A. flavus is the main pathogen threatening transplant recipients and cancer patients worldwide. In this study, A. flavus had low levels of the gpaB gene expression compared to A. fumigatus (p=0.006). The highest sidA expression was detected in transplant recipients (p=0.05). There was no significant correlation between sidA expression and underlying disease (p=0.15). The sidA and gpaB gene expression patterns may provide evidence that these virulence genes play important roles in the pathogenicity of Aspergillus isolates; however, there are several regulatory genes responsible for the unexpressed sidA and gpaB genes in the isolates. Copyright © 2018 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.
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A High-Pressure Study of Manganese Metal and its Reactions with CO2 at 6, 23, and 44 GPa
NASA Astrophysics Data System (ADS)
Sawchuk, K. L. S.; McGuire, C. P.; Greenburg, A.; Makhluf, A.; Kavner, A.
2017-12-01
The free energies of formation of oxides and carbonates at the extreme pressures and temperatures of Earth's interior provides some of the thermodynamic constrains for models of mantle/core formation and subsequent chemical evolution. The broad goal of our research program is to measure the pressure- and temperature-dependence of free energies of formation of transition metal oxides and carbonates. This requires measurements of the phase stability, density, and thermoelastic properties of metals, oxides, and carbonates at deep-Earth and planetary conditions. Manganese is of interest because it is one of the most abundant transition metal geochemical tracers, it readily forms a carbonate at ambient pressure, and its high-pressure carbonate and oxide densities and equation of state parameters are relatively unknown. Here we report new data on the pressure/volume equation of state and structure of manganese metal as well as its reactions with CO2. These measurements were made using a laser heated diamond anvil cell in conjunction with synchrotron-based X-ray diffraction at beamline 12.2.2 at the Advanced Light Source. Three samples of manganese metal were gas-loaded in a CO2 pressure medium and pressurized to 6, 23, and 44 GPa. Upon laser heating, the CO2 reacted with the Mn metal generating new phases. To analyze the diffraction patterns, we we use a python-based program developed in-house for extracting high resolution 2-dimensional diffraction peak position and intensity information from two-dimensional X-ray diffraction patterns. At each pressure step, the structure and density of the quenched Mn metal phase was determined. At 6 GPa, Mn metal adopts a BCC structure, and at 23 GPa a tetragonal distortion is observed in the lattice. The measured equation of state is in good agreement with an existing meaurement by Fujihisa and Takemura (1995). MnCO3 rhodochrosite is observed in the sample quenched after heating at 6 GPa. Additional high pressure phases are evident
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School Attendance Revisited: A Study of Urban African American Students' GPA and Coping Strategies.
ERIC Educational Resources Information Center
Steward, Robbie J.; Steward, Astin Devine; Blair, Jonathan
This study investigated the degree to which at-risk, urban, African American high school students' coping strategies and grade point average (GPA) would predict attendance. Data were collected from 100 high school freshmen using the Adolescent Coping Orientation for Problem Experiences. Students' GPAs were identified through school records.…
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Ortega, Marcos E.; Gaussier, Helene; Catalano, Carlos E.
2007-01-01
Summary Terminase enzymes are common to double-stranded DNA (dsDNA) viruses and are responsible for packaging viral DNA into the confines of an empty capsid shell. In bacteriophage lambda the catalytic terminase subunit is gpA, which is responsible for maturation of the genome end prior to packaging and subsequent translocation of the matured DNA into the capsid. DNA packaging requires an ATPase catalytic site situated in the N-terminus of the protein. A second ATPase catalytic site associated with the DNA maturation activities of the protein has been proposed; however, direct demonstration of this putative second site is lacking. Here we describe biochemical studies that define protease-resistant peptides of gpA and expression of these putative domains in E. coli. Biochemical characterization of gpA-ΔN179, a construct in which the N-terminal 179 residues of gpA have been deleted, indicates that this protein encompasses the DNA maturation domain of gpA. The construct is folded, soluble and possesses an ATP-dependent nuclease activity. Moreover, the construct binds and hydrolyzes ATP despite the fact that the DNA packaging ATPase site in the N-terminus of gpA has been deleted. Mutation of lysine 497, which alters the conserved lysine in a predicted Walker A “P-loop” sequence, does not affect ATP binding but severely impairs ATP hydrolysis. Further, this mutation abrogates the ATP-dependent nuclease activity of the protein. These studies provide direct evidence for the elusive nucleotide-binding site in gpA that is directly associated with the DNA maturation activity of the protein. The implications of these results with respect to the two roles of the terminase holoenzyme – DNA maturation and DNA packaging – are discussed. PMID:17870092
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NASA Astrophysics Data System (ADS)
Kunimoto, Takehiro; Irifune, Tetsuo; Tange, Yoshinori; Wada, Kouhei
2016-04-01
A pressure generation test for Kawai-type multianvil apparatus (KMA) has been made using second-stage anvils of a newly developed ultra-hard tungsten carbide composite. Superb performance of the new anvil with significantly less plastic deformation was confirmed as compared to those commonly used for the KMA experiments. A maximum pressure of ∼48 GPa was achieved using the new anvils with a truncation edge length (TEL) of 1.5 mm, based on in situ X-ray diffraction measurements. Further optimization of materials and sizes of the pressure medium/gasket should lead to pressures even higher than 50 GPa in KMA using this novel tungsten carbide composite, which may also be used for expansion of the pressure ranges in other types of high pressure apparatus operated in large volume press.
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Robust zero resistance in a superconducting high-entropy alloy at pressures up to 190 GPa
Guo, Jing; Wang, Honghong; von Rohr, Fabian; Wang, Zhe; Cai, Shu; Zhou, Yazhou; Yang, Ke; Li, Aiguo; Jiang, Sheng; Wu, Qi; Cava, Robert J.; Sun, Liling
2017-01-01
We report the observation of extraordinarily robust zero-resistance superconductivity in the pressurized (TaNb)0.67(HfZrTi)0.33 high-entropy alloy––a material with a body-centered-cubic crystal structure made from five randomly distributed transition-metal elements. The transition to superconductivity (TC) increases from an initial temperature of 7.7 K at ambient pressure to 10 K at ∼60 GPa, and then slowly decreases to 9 K by 190.6 GPa, a pressure that falls within that of the outer core of the earth. We infer that the continuous existence of the zero-resistance superconductivity from 1 atm up to such a high pressure requires a special combination of electronic and mechanical characteristics. This high-entropy alloy superconductor thus may have a bright future for applications under extreme conditions, and also poses a challenge for understanding the underlying quantum physics. PMID:29183981
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Robust zero resistance in a superconducting high-entropy alloy at pressures up to 190 GPa
NASA Astrophysics Data System (ADS)
Guo, Jing; Wang, Honghong; von Rohr, Fabian; Wang, Zhe; Cai, Shu; Zhou, Yazhou; Yang, Ke; Li, Aiguo; Jiang, Sheng; Wu, Qi; Cava, Robert J.; Sun, Liling
2017-12-01
We report the observation of extraordinarily robust zero-resistance superconductivity in the pressurized (TaNb)0.67(HfZrTi)0.33 high-entropy alloy--a material with a body-centered-cubic crystal structure made from five randomly distributed transition-metal elements. The transition to superconductivity (TC) increases from an initial temperature of 7.7 K at ambient pressure to 10 K at ˜60 GPa, and then slowly decreases to 9 K by 190.6 GPa, a pressure that falls within that of the outer core of the earth. We infer that the continuous existence of the zero-resistance superconductivity from 1 atm up to such a high pressure requires a special combination of electronic and mechanical characteristics. This high-entropy alloy superconductor thus may have a bright future for applications under extreme conditions, and also poses a challenge for understanding the underlying quantum physics.
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Young, David A.; Cynn, Hyunchae; Soderlind, Per; ...
2016-10-24
Most of the chemical elements have now been compressed close to or above 100 GPa (1 Mbar) pressure in diamond-anvil cells and the pressure–volume room-temperature isotherms have been measured. We collect these data and use simple lattice-dynamics models to reduce the isotherms to 0 K. We have extended the published work by making new diamond-anvil-cell measurements on Cr and Rh, and by conducting density-functional calculations on the elements Po, At, Rn, Fr, Ra, and Ac. The 0 K data are tabulated for all elements 1 ≤ Z ≤ 92 and 0 ≤ P ≤ 100 GPa. These data are usefulmore » for generating wide-range equation of state models and for studying the stability of chemical compounds at high pressure (“Megabar chemistry”). As a result, the tables presented here are intended to be reference thermodynamic tables for use in high-pressure research. Further experimental and theoretical work will be needed to extend the tables to higher pressure and to improve accuracy.« less
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Shock Compression of the New 47Zr45Ti5Al3V Alloys up to 200 GPa
NASA Astrophysics Data System (ADS)
Zhang, Pin-Liang; Gong, Zi-Zheng; Ji, Guang-Fu; Wang, Qing-Song; Song, Zhen-Fei; Cao, Yan; Wang, Xiang
2013-06-01
Shock compression experiments on a new kind of 47Zr45Ti5Al3V alloys at pressures between 28 and 200 GPa are performed using a two-stage light gas gun. The Hugoniot data are obtained by combining the impedance-match method and the electrical probe technique. The relationship between the shock wave velocity Us and particle velocity up can be described linearly by Us = 4.324(±0.035) + 1.177(±0.012)up. No obvious evidence of phase transition is found in the shock compression pressure range. The calculated Us - up relationship obtained from the additive principle is different from the experimental data, indicating that the α → β phase transition occurs below 28 GPa. The Grüneisen parameter γ obtained from the experimental data can be expressed by γ = 1.277(ρ0/ρ). The zero-pressure bulk modulus B0s = 97.96 GPa and its pressure derivative B'0s = 3.68. The P—V—T equation of state for 47Zr45Ti5Al3V is given using the Vinet equation of state to describe the cold curve and the Debye model for the thermal contributions.
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NASA Astrophysics Data System (ADS)
Zhang, Youjun; Sekine, Toshimori; He, Hongliang; Yu, Yin; Liu, Fusheng; Zhang, Mingjian
2014-07-01
The shock Hugoniot of an Fe-9 wt %Ni-10 wt %Si system as a model of the Earth's core has been measured up to ~280 GPa using a two-stage light-gas gun. The samples had an average density of 6.853 (±0.036) g/cm3. The relationship between shock velocity (Us) and particle velocity (up) can be described by Us (km/s) = 3.95 (±0.15) + 1.53 (±0.05) up (km/s). The calculated Hugoniot temperatures and the melting curve indicate that the model composition melts above a shock pressure of ~168 GPa, which is significantly lower than the shock-melting pressure of iron (~225 GPa). A comparison of the pressure-density (P-ρ) profiles between the model composition and the preliminary reference Earth model gives a silicon content close to 10 wt %, necessary to compensate the density deficit in the Earth's outer core from seismological observations, if silicon is present as a major light element in the Fe-Ni core system.
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Graphite to diamond transformation during sediment-peridotite interaction at 7.5 and 10.5 GPa
NASA Astrophysics Data System (ADS)
Girnis, A. V.; Brey, G. P.; Bulatov, V. K.; Höfer, H. E.; Woodland, A. B.
2018-06-01
Diamond nucleation and growth were investigated experimentally at 7.5 and 10.5 GPa and temperatures up to 1500 °C. Samples consisted of two layers: i) H2O- and CO2-bearing model sediment and ii) graphite-bearing garnet harzburgite comprising natural minerals. Two experimental series were conducted, one under a controlled temperature gradient with the sedimentary layer usually in the cold zone and the other under isothermal conditions. In the latter case, diamond seeds were added to the sedimentary mixture. During the experiments, the sedimentary layer partially or completely melted, with the melt percolating and interacting with the adjacent harzburgite. The graphite-to-diamond transition in the peridotite was observed above 1300 °C at 7.5 GPa and 1200 °C at 10.5 GPa in the temperature-gradient experiments, and at temperatures 100 °C lower in the isothermal experiments with diamond seeds. Newly formed diamond occurs mostly as individual grains up to 10 μm in size and is separate from graphite aggregates. In some cases, an association of diamond with magnesite was observed. Diamond nucleation occurs in hydrous and CO2-bearing silicate melt following graphite dissolution and recrystallization. In the case of the diamond-magnesite association, diamond was probably formed through carbonate reduction coupled with graphite oxidation. The composition of the melts ranged from "carbonatitic" with 10 wt% SiO2 and >50 wt% volatiles to hydrous silicate with 40 wt% SiO2 and <10 wt% volatiles. This variation has no strong effect on diamond nucleation or growth.
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NASA Astrophysics Data System (ADS)
Friedlander, Lonia R.; Glotch, Timothy D.; Bish, David L.; Dyar, M. Darby; Sharp, Thomas G.; Sklute, Elizabeth C.; Michalski, Joseph R.
2015-05-01
Many phyllosilicate deposits remotely detected on Mars occur within bombarded terrains. Shock metamorphism from meteor impacts alters mineral structures, producing changed mineral spectra. Thus, impacts have likely affected the spectra of remotely sensed Martian phyllosilicates. We present spectral analysis results for a natural nontronite sample before and after laboratory-generated impacts over five peak pressures between 10 and 40 GPa. We conducted a suite of spectroscopic analyses to characterize the sample's impact-induced structural and spectral changes. Nontronite becomes increasingly disordered with increasing peak impact pressure. Every infrared spectroscopic technique used showed evidence of structural changes at shock pressures above ~25 GPa. Reflectance spectroscopy in the visible near-infrared region is primarily sensitive to the vibrations of metal-OH and interlayer H2O groups in the nontronite octahedral sheet. Midinfrared (MIR) spectroscopic techniques are sensitive to the vibrations of silicon and oxygen in the nontronite tetrahedral sheet. Because the tetrahedral and octahedral sheets of nontronite deform differently, impact-driven structural deformation may contribute to differences in phyllosilicate detection between remote sensing techniques sensitive to different parts of the nontronite structure. Observed spectroscopic changes also indicated that the sample's octahedral and tetrahedral sheets were structurally deformed but not completely dehydroxylated. This finding is an important distinction from previous studies of thermally altered phyllosilicates in which dehydroxylation follows dehydration in a stepwise progression preceding structural deformation. Impact alteration may thus complicate mineral-specific identifications based on the location of OH-group bands in remotely detected spectra. This is a key implication for Martian remote sensing arising from our results.
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Shock compression of liquid silicates to 125 GPa: the anorthite-diopside join
NASA Astrophysics Data System (ADS)
Asimow, P. D.; Ahrens, T. J.
2008-12-01
Shock compression of pre-heated liquid silicates provides, at present, the only method for direct measurement of the equation of state of such liquids at lower mantle pressures. At previous AGU meetings we have reported the extension of the pre-heated Hugoniot of the anorthite-diopside eutectic composition Di64An36, initially at 1673 K, to 110 GPa, along with a determination of the density dependence of the Grüneisen parameter of this liquid composition. We have now completed this work by: (1) extending the Di64An36 data to 127 GPa; (2) measuring the diopside (CaMgSi2O6) end-member composition, initially at 1773 K, to 114 GPa; and (3) measuring the anorthite (CaAl2Si2O8) end-member composition, initially at 1923 K, to 125 GPa. For internal consistency we have also re-reduced all of the experiments reported by Rigden et al. (1984, 1988, 1989) as well as some unpublished data from that era, using the latest initial melt densities (Lange, 1997) and hot Mo equation of state (Asimow et al., 2008). We are now in a position to assess the compression behavior of each of these liquids and the model of linear mixing along the compositional join to all pressures relevant to the terrestrial mantle. The total data set for the Di64An36 and diopside compositions can be fit within error by straight line Hugoniots in particle velocity vs. shock velocity. This suggests that a 3rd order equation of state is adequate to describe compression of these liquids over large pressure ranges. Anorthite, on the other hand, clearly requires a more complex model, such as we require for MgSiO3 and Mg2SiO4 liquids (Mosenfelder, Asimow, and Ahrens; this meeting); we examine the 4th-order Birch-Murnaghan and Ghiorso equations of state as well as an explicit speciation model that accounts for continuous coordination change of Si and Al. The complexity of anorthite liquid compression causes an apparent failure of linear mixing, suggesting that calibration of a predictive model of the equation of
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NASA Astrophysics Data System (ADS)
Bollengier, O.; Brown, J. M.; Vance, S.; Shaw, G. H.
2015-12-01
Geophysical data from the Galileo and Cassini-Huygens missions are consistent with the presence of aqueous subsurface oceans in Ganymede, Callisto and Titan, the largest icy satellites of the solar system. To understand the history and present state of these moons, the next generation of evolution models will require an accurate description of the properties of these liquid layers to predict the phase boundaries, heat transports and chemical exchanges within them. Sound speed measurements in pressure and temperature allow for the reconstruction of the Gibbs free energy surface of a phase, which in turn gives access to the desired properties (chemical potential, density, heat capacity...). However, such data are still scarce for aqueous solutions bearing Na+, Mg2+, Cl- and SO42- ions (major ions expected in extra-terrestrial oceans) at the high pressures and low temperatures expected for water inside these moons (up to 1.5 GPa for Ganymede, down to freezing temperatures). For pure water, IAPWS accuracy for sound speeds is given to 0.3% above 0.4 GPa. MgSO4aqueous solutions have been explored to 0.7 GPa with a precision limited to about 0.5%. Most other aqueous solutions bearing any combination of these four ions have not been explored at all above a few hundreds MPa. To acquire new high-precision sound speeds in aqueous solutions of various compositions, we set up a new experimental system working in the 0 - 0.7 GPa pressure range and 240 - 350 K temperature range. The device consists in an oil-pressurized steel vessel enclosing a titanium alloy rod supporting the sample and a sealing bellows. A transducer at the top end of the titanium rod generates ultrasonic waves and collects the series of subsequent reflections. Preliminary tests with pure water illustrate a precision of 0.02% and an accuracy within 0.1% of IAPWS on our whole pressure range. Revision of the properties of pure water and H2O-MgSO4 solutions up to 0.7 GPa along with the first data in the H2O-MgCl2
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Dual Credit Enrollment and GPA by Ethnicity and Gender at Texas 2-Year Colleges
ERIC Educational Resources Information Center
Young, Robert D., Jr.
2013-01-01
Purpose: The purpose of this investigation was to determine the extent to which differences were present in dual credit course enrollment. Specifically examined were whether differences were present in the first semester GPA and at the end of the first two semesters for students who enrolled in dual credit courses while in high school from…
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NASA Astrophysics Data System (ADS)
Lv, M.; Dorfman, S.; Liu, J.; Farmer, A. B.; Potapkin, V.; Chumakov, A. I.; McCammon, C. A.; Greenberg, E.; Prakapenka, V. B.; Popov, D.
2017-12-01
The spin and valence state of Fe in (Mg,Fe,Al)(Si,Fe,Al)O3 bridgmanite and silicate melts is important to understanding the composition, structure, and dynamics of the Earth's lower mantle. Previous experimental and theoretical studies conclude that Fe3+ in B-site of bridgmanite undergoes a high spin (HS) to low spin (LS) transition, but conflicting measurements of spin transition pressures (18-70 GPa) and significant disagreement on hyperfine parameters of LS Fe3+ need to be resolved. We performed energy-domain synchrotron Mössbauer spectroscopy (E-SMS) and X-ray diffraction (XRD) experiments up to 91 GPa (corresponding to 2000 km depth in the mid lower mantle) to explore the electronic behavior of Fe in both silicate glass and bridgmanite with measured composition (Mg0.97Fe0.20Si0.90O3). Fe3+ and Fe2+ were identified on the basis of center shift (CS) at 1 bar of 0.4 and 1 mm/s, respectively. The Mössbauer spectra of glass exhibit a continuous spin transition of Fe3+ between 11 to 40 GPa, while Fe2+ adopts the HS state up to 91 GPa. Bridgmanite Mössbauer spectra indicate two HS Fe2+ doublets corresponding to local distortion of the A-site, and that the bulk of the Fe3+ exhibits quadrupole splitting (QS) ranging from 0.8-1.3 mm/s over the entire pressure range studied. Because stoichiometry suggests most Fe3+ occupies the B-site, if the spin transition occurs it must have a small effect on Mössbauer parameters, as observed in recent studies of (Mg0.5Fe1.0Si0.5O3) and (Mg0.97Fe0.06Si0.97O3) bridgmanite. No discontinuity or softening is observed in the equation of state (EOS) of the bridgmanite between 38-103 GPa and 300 K. The bulk modulus and unit cell volume at ambient conditions obtained by fitting the unit cell volume data to the second-order Birch-Murnaghan EOS are 264(3) GPa and 163.6(3) Å3, respectively, consistent with previous studies of (Mg0.90Fe0.20Si0.90O3) bridgmanite. The spin transition in Fe3+ may have too small an effect on elastic properties
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Experimental investigation of dynamic compression and spallation of Cerium at pressures up to 6 GPa
NASA Astrophysics Data System (ADS)
Zubareva, A. N.; Kolesnikov, S. A.; Utkin, A. V.
2014-05-01
In this study the experiments on one-dimensional dynamic compression of Cerium (Ce) samples to pressures of 0.5 to 6 GPa using various types of explosively driven generators were conducted. VISAR laser velocimeter was used to obtain Ce free surface velocity profiles. The isentropic compression wave was registered for γ-phase of Ce at pressures lower than 0.76 GPa that corresponds to γ-α phase transition pressure in Ce. Shock rarefaction waves were also registered in several experiments. Both observations were the result of the anomalous compressibility of γ-phase of Ce. On the basis of our experimental results the compression isentrope of Ce γ-phase was constructed. Its comparison with volumetric compression curves allowed to estimate the magnitude of shear stress at dynamic compression conditions for Ce. Spall strength measurements were also conducted for several samples. They showed a strong dependence of the spall strength of Ce on the strain rate.
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Structural and magnetic transition in stainless steel Fe-21Cr-6Ni-9Mn up to 250 GPa
NASA Astrophysics Data System (ADS)
Liu, Lei; Hou, Qi-Yue; Zhang, Yi; Jing, Qiu-Min; Wang, Zhi-Gang; Bi, Yan; Xu, Ji-An; Li, Xiao-Dong; Li, Yan-Chun; Liu, Jing
2015-06-01
Stainless steel Fe-21Cr-6Ni-9Mn (SS 21-6-9), with ˜21% Cr, ˜6% Ni, and ˜9% Mn in weight percentage, has wide applications in extensive fields. In the present study, SS 21-6-9 is compressed up to 250 GPa, and its crystal structures and compressive behaviors are investigated simultaneously using the synchrotron angle-dispersive x-ray diffraction technique. The SS 21-6-9 undergoes a structural phase transition from fcc to hcp structure at ˜12.8 GPa with neglectable volume collapse within the determination error under the quasi-hydrostatic environment. The hcp structure remains stable up to the highest pressure of 250 GPa in the present experiments. The antiferromagnetic-to-nonmagnetic state transition of hcp SS 21-6-9 with the changes of inconspicuous density and structure, is discovered at ˜50 GPa, and revealed by the significant change in c/a ratio. The hcp SS-21-6-9 is compressive anisotropic: it is more compressive in the c-axis direction than in the a-axis direction. Both the equations of states (EOSs) of fcc and hcp SS 21-6-9, which are in accordance with those of fcc and hcp pure irons respectively, are also presented. Furthermore, the c/a ratio of hcp SS 21-6-9 at infinite compression, R∞, is consistent with the values of pure iron and Fe-10Ni alloy. Project supported by the National Natural Science Foundation of China (Grant Nos. U1230201, 11274281, and 11304294), the Industrial Technology Development Program, China (Grant No. 9045140509), and the Funds from the Chinese Academy of Sciences (Grant Nos. KJCX2-SW-N03 and KJCX2-SW-N20).
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The system CaO-MgO-SiO2-CO2 at 1 GPa, metasomatic wehrlites, and primary carbonatite magmas
NASA Astrophysics Data System (ADS)
Lee, W. J.; Wyllie, P. J.
New experimental data in CaO-MgO-SiO2-CO2 at 1GPa define the vapor-saturated silicate-carbonate liquidus field boundary involving primary minerals calcite, forsterite and diopside. The eutectic reaction for melting of model calcite (1% MC)-wehrlite at 1GPa is at 1100°C, with liquid composition (by weight) 72% CaCO3 (CC), 9% MgCO3 (MC), and 18% CaMgSi2O6 (Di). These data combined with previous results permit construction of the isotherm-contoured vapor-saturated liquidus surface for the calcite/dolomite field, and part of the adjacent forsterite and diopside fields. Nearly pure calcite crystals in mantle xenoliths cannot represent equilibrium liquids. We recently determined the complete vapor-saturated liquidus surface between carbonates and model peridotites at 2.7GPa the peritectic reaction for dolomite (25% MC)-wehrlite at 2.7GPa occurs at 1300°C, with liquid composition 60% CC, 29% MC, and 11% Di. The liquidus field boundaries on these two surfaces provide the road-map for interpretation of magmatic processes in various peridotite-CO2 systems at depths between the Moho and about 100km. Relationships among kimberlites, melilitites, carbonatites and the liquidus phase boundaries are discussed. Experimental data for carbonatite liquid protected by metasomatic wehrlite have been reported. The liquid trends directly from dolomitic towards CaCO3 with decreasing pressure. The 1.5GPa liquid contains 87% CC and 4% Di, much lower in silicate components than our phase boundary. However, the liquids contain approximately the same CaCO3 (90+/- 1wt%) in terms of only carbonate components. For CO2-bearing mantle, all magmas at depth must pass through initial dolomitic compositions. Rising dolomitic carbonatite melt will vesiculate and may erupt as primary magmas through cracks from about 70km. If it percolates through metasomatic wehrlite from 70km toward the Moho at 35-40km, primary calcic siliceous carbonatite magma can be generated with silicate content at least 11
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ERIC Educational Resources Information Center
Megert, Diann Ackerman
2005-01-01
This research examined the high school transcripts of honors scholarship recipients to identify a better criterion for awarding scholarships than high school grade point average (GPA) alone. Specifically, this study compared the honors scholarship retention rate when the scholarship was awarded based on completed advanced high school math classes…
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NASA Astrophysics Data System (ADS)
Kuwayama, Yasuhiro; Hirose, Kei; Sata, Nagayoshi; Ohishi, Yasuo
2008-09-01
We have investigated the phase relations of iron and iron-nickel alloys with 18 to 50 wt.% Ni up to over 300 GPa using a laser-heated diamond-anvil cell. The synchrotron X-ray diffraction measurements show the wide stability of hcp-iron up to 301 GPa and 2000 K and 319 GPa and 300 K without phase transition to dhcp, orthorhombic, or bcc phases. On the other hand, the incorporation of nickel has a remarkable effect on expanding the stability field of fcc phase. The geometry of the temperature-composition phase diagram of iron-nickel alloys suggests that the hcp-fcc-liquid triple point is located at 10 to 20 wt.% Ni at the pressure of the inner core boundary. The fcc phase could crystallize depending on the nickel and silicon contents in the Earth's core, both of which are fcc stabilizer.
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Melting of metasomatized peridotite at 4-6 GPa and up to 1200 °C: an experimental approach
NASA Astrophysics Data System (ADS)
Kessel, R.; Pettke, T.; Fumagalli, P.
2015-04-01
The phase assemblages and compositions in a K-bearing lherzolite + H2O system are determined between 4 and 6 GPa and 850-1200 °C, and the melting reactions occurring at subarc depth in subduction zones are constrained. Experiments were performed on a rocking multi-anvil apparatus. The experiments had around 16 wt% water content, and hydrous melt or aqueous fluid was segregated and trapped in a diamond aggregate layer. The compositions of the aqueous fluid and hydrous melt phases were measured using the cryogenic LA-ICP-MS technique. The residual lherzolite consists of olivine, orthopyroxene, clinopyroxene, and garnet, while diamond (C) is assumed to be inert. Hydrous and alkali-rich minerals were absent from the run products due to preferred dissolution of K2O (and Na2O) to the aqueous fluid/hydrous melt phases. The role of phlogopite in melting relations is, thus, controlled by the water content in the system: at the water content of around 16 wt% used here, phlogopite is unstable and thus does not participate in melting reactions. The water-saturated solidus, i.e., the first appearance of hydrous melt in the K-lherzolite composition, is located between 900 and 1000 °C at 4 GPa and between 1000 and 1100 °C at 5 and 6 GPa. Compositional jumps between hydrous melt and aqueous fluid at the solidus include a significant increase in the total dissolved solids load. All melts/fluids are peralkaline and calcium-rich. The melting reactions at the solidus are peritectic, as olivine, clinopyroxene, garnet, and H2O are consumed to generate hydrous melt plus orthopyroxene. Our fluid/melt compositional data demonstrate that the water-saturated hybrid peridotite solidus lies above 1000 °C at depths greater than 150 km and that the second critical endpoint is not reached at 6 GPa for a K2O-Na2O-CaO-FeO-MgO-Al2O3-SiO2-H2O-Cr2O3(-TiO2) peridotite composition.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Dong, Yongkwan; McGuire, Michael A.; Malik, Abds-Sami, E-mail: abds-sami.malik@diamondinnovations.co
2009-10-15
The thermoelectric properties of nominally undoped PbTe and Br doped PbTe materials sintered at high-pressure and high-temperature (HPHT) have been studied. All samples show n-type semiconducting behavior with negative thermopower. For undoped PbTe, four different HPHT treatments were performed at pressures between 4.0 and 6.5 GPa. PbTe doped with Br at 0.5, 1.0, 2.0, 3.0x10{sup 19} cm{sup -3} was HPHT treated at 4.0 GPa and 1045 deg. C. As the dopant concentration increases, the absolute thermopower decreases, thermal conductivity increases, and electrical resistivity decreases. At a nominal dopant concentration of 1.0x10{sup 19} cm{sup -3}, carrier mobility of 1165 cm{sup 2}/Vmore » s and dimensionless thermoelectric figure-of-merit, ZT, of around 0.27 at 300 K were obtained. These results demonstrate that HPHT post-processing is a viable and controllable way of tuning the thermoelectric properties of PbTe-based materials. - Abstract: The effect, on thermoelectric properties, of sintering undoped and Br doped PbTe at pressures >=4.0 GPa and 1045 deg. C are reported and compared with conventionally sintered materials. Display Omitted« less
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Effect of the fcc-hcp martensitic transition on the equation of state of solid krypton up to 140 GPa
NASA Astrophysics Data System (ADS)
Rosa, A. D.; Garbarino, G.; Briggs, R.; Svitlyk, V.; Morard, G.; Bouhifd, M. A.; Jacobs, J.; Irifune, T.; Mathon, O.; Pascarelli, S.
2018-03-01
Solid krypton (Kr) undergoes a pressure-induced martensitic phase transition from a face-centered cubic (fcc) to a hexagonal close-packed (hcp) structure. These two phases coexist in a very wide pressure domain inducing important modifications of the bulk properties of the resulting mixed phase system. Here, we report a detailed in situ x-ray diffraction and absorption study of the influence of the fcc-hcp phase transition on the compression behavior of solid krypton in an extended pressure domain up to 140 GPa. The onset of the hcp-fcc transformation was observed in this study at around 2.7 GPa and the coexistence of these two phases up to 140 GPa, the maximum investigated pressure. The appearance of the hcp phase is also evidenced by the pressure-induced broadening and splitting of the first peak in the XANES spectra. We demonstrate that the transition is driven by a continuous nucleation and intergrowth of nanometric hcp stacking faults that evolve in the fcc phase. These hcp stacking faults are unaffected by high-temperature annealing, suggesting that plastic deformation is not at their origin. The apparent small Gibbs free-energy differences between the two structures that decrease upon compression may explain the nucleation of hcp stacking faults and the large coexistence domain of fcc and hcp krypton. We observe a clear anomaly in the equation of state of the fcc solid at ˜20 GPa when the proportion of the hcp form reaches ˜20 % . We demonstrate that this anomaly is related to the difference in stiffness between the fcc and hcp phases and propose two distinct equation of states for the low and high-pressure regimes.
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Raman spectroscopic study of DL valine under pressure up to 20 GPa
NASA Astrophysics Data System (ADS)
Rêgo, F. S. C.; Lima, J. A.; Freire, P. T. C.; Melo, F. E. A.; Mendes Filho, J.; Polian, A.
2016-04-01
DL-valine crystal was studied by Raman spectroscopy under hydrostatic pressure using a diamond anvil cell from ambient pressure up to 19.4 GPa in the spectral range from 40 to 3300 cm-1. Modifications in the spectra furnished evidence of the occurrence of two structural phase transitions undergone by this racemic amino acid crystal. The classification of the vibrational modes, the behavior of their wavenumber as a function of the pressure and the reversibility of the phase transitions are discussed.
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High Pressure Elastic Behavior of Synthetic Mg 3 Y 2 (SiO 4 ) 3 Garnet up to 9 GPa
Fan, Dawei; Ma, Maining; Wei, Shuyi; ...
2013-01-01
Tmore » he compression behavior of synthetic magnesium- (Mg-) yttrium (Y) garnet Mg 3 Y 2 (SiO 4 ) 3 has been investigated upto about 8.79 GPa at 300 K using in situ angle-dispersive X-ray diffraction and a diamond anvil cell at the beamline X17C, National Synchrotron Light Source, Brookhaven National Laboratory. No phase transition has been observed within the pressure range investigated. he unit-cell parameters and volume decreased systematically with increasing pressure, and a reliable isothermal bulk modulus ( K 0 ) and its pressure derivative ( K 0 ′ ) were obtained in this study. he values of zero-pressure volume V 0 , K 0 , and K 0 ′ refined with a third-order Birch-Murnaghan equation of state are V 0 = 1727.9 ± 0.2 Å 3 , K 0 = 145 ± 3 GPa, and K 0 ′ = 8.5 ± 0.9 . If K 0 ′ is fixed at 4, K 0 is obtained as 158 ± 2 GPa.« less
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High Pressure Elastic Behavior of Synthetic Mg 3 Y 2 (SiO 4 ) 3 Garnet up to 9 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fan, Dawei; Ma, Maining; Wei, Shuyi
Tmore » he compression behavior of synthetic magnesium- (Mg-) yttrium (Y) garnet Mg 3 Y 2 (SiO 4 ) 3 has been investigated upto about 8.79 GPa at 300 K using in situ angle-dispersive X-ray diffraction and a diamond anvil cell at the beamline X17C, National Synchrotron Light Source, Brookhaven National Laboratory. No phase transition has been observed within the pressure range investigated. he unit-cell parameters and volume decreased systematically with increasing pressure, and a reliable isothermal bulk modulus ( K 0 ) and its pressure derivative ( K 0 ′ ) were obtained in this study. he values of zero-pressure volume V 0 , K 0 , and K 0 ′ refined with a third-order Birch-Murnaghan equation of state are V 0 = 1727.9 ± 0.2 Å 3 , K 0 = 145 ± 3 GPa, and K 0 ′ = 8.5 ± 0.9 . If K 0 ′ is fixed at 4, K 0 is obtained as 158 ± 2 GPa.« less
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NASA Astrophysics Data System (ADS)
Ransom, T. C.; Ahart, Muhtar; Hemley, Russell J.; Roland, C. M.
2018-05-01
Brillouin scattering was performed on an elastomeric polyurea, an important technological polymer. Being widely used for impact modification, of particular interest is its response to extreme pressure conditions. We applied pressures up to 13.5 GPa using a diamond anvil cell and measured the longitudinal and transverse sound velocities via Brillouin light scattering. From these data, the equation of state, the elastic moduli, and Poisson's ratio were obtained. By comparison with previous dilatometry measurements up to 1 GPa, we show how viscoelastic effects can be accounted for in order to obtain an accurate equation of state. Because of the extreme strain-rate hardening of vitrifying polyurea, the property changes associated with its solidification are more subtle in the high frequency Brillouin data than observed in conventional mechanical testing and dilatometry.
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Pressure-dependent decomposition kinetics of the energetic material HMX up to 3.6 GPa.
Glascoe, Elizabeth A; Zaug, Joseph M; Burnham, Alan K
2009-12-03
The effect of pressure on the global thermal decomposition rate of the energetic material HMX was studied. HMX was precompressed in a diamond anvil cell (DAC) and heated at various rates. The parent species population was monitored as a function of time and temperature using Fourier transform infrared (FTIR) spectroscopy. Global decomposition rates were determined by fitting the fraction reacted to the extended-Prout-Tompkins nucleation-growth model and the Friedman isoconversional method. The results of these experiments and analysis indicate that pressure accelerates the decomposition at low-to-moderate pressures (i.e., between ambient pressure and 0.1 GPa) and decelerates the decomposition at higher pressures. The decomposition acceleration is attributed to pressure-enhanced autocatalysis, whereas the deceleration at high pressures is attributed to pressure-inhibiting bond homolysis step(s), which would result in an increase in volume. These results indicate that both the beta- and delta-polymorphs of HMX are sensitive to pressure in the thermally induced decomposition kinetics.
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Deflagration rates of secondary explosives under static MPa - GPa pressure
NASA Astrophysics Data System (ADS)
Zaug, Joseph; Young, Christopher; Glascoe, Elizabeth; Maienschein, Jon; Hart, Elaine; Long, Gregory; Black, Collin; Sykora, Gregory; Wardell, Jeffrey
2009-06-01
We discuss our measurements of the chemical reaction propagation rate (RPR) as a function of pressure using diamond anvil cell (DAC) and strand burner technologies. Materials investigated include HMX and RDX crystalline powders, LX-04 (85% HMX and 15% Viton A), and Comp B (63% RDX, 36% TNT, 1% wax). The anomalous correspondence between crystal structure, including in some instances isostructural phase transitions, on pressure dependant RPRs of TATB, HMX, Nitromethane, and Viton are elucidated using micro -IR and -Raman spectroscopies. The contrast between DAC GPa and strand burner MPa regime measurements yields insight into explosive material burn phenomena. Here we highlight pressure dependent physicochemical mechanisms that appear to affect the deflagration rate of precompressed energetic materials.
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Serizawa, Toru; Higuchi, Yoshinori; Nagano, Osamu; Hirai, Tatsuo; Ono, Junichi; Saeki, Naokatsu; Miyakawa, Akifumi
2012-12-01
The authors conducted validity testing of the 5 major reported indices for radiosurgically treated brain metastases- the original Radiation Therapy Oncology Group's Recursive Partitioning Analysis (RPA), the Score Index for Radiosurgery in Brain Metastases (SIR), the Basic Score for Brain Metastases (BSBM), the Graded Prognostic Assessment (GPA), and the subclassification of RPA Class II proposed by Yamamoto-in nearly 2500 cases treated with Gamma Knife surgery (GKS), focusing on the preservation of neurological function as well as the traditional endpoint of overall survival. The authors analyzed data from 2445 cases treated with GKS by the first author (T.S.), the primary surgeon. The patient group consisted of 1716 patients treated between January 1998 and March 2008 (the Chiba series) and 729 patients treated between April 2008 and December 2011 (the Tokyo series). The interval from the date of GKS until the date of the patient's death (overall survival) and impaired activities of daily living (qualitative survival) were calculated using the Kaplan-Meier method, while the absolute risk for two adjacent classes of each grading system and both hazard ratios and 95% confidence intervals were estimated using the Cox proportional hazards model. For overall survival, there were highly statistically significant differences between each two adjacent patient groups characterized by class or score (all p values < 0.001), except for GPA Scores 3.5-4.0 and 3.0. The SIR showed the best statistical results for predicting preservation of neurological function. Although no other grading systems yielded statistically significant differences in qualitative survival, the BSBM and the modified RPA appeared to be better than the original RPA and GPA. The modified RPA subclassification, proposed by Yamamoto, is well balanced in scoring simplicity with respect to case number distribution and statistical results for overall survival. However, a new or revised grading system is
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Phase transitions in orthopyroxene (En 90) to 49GPa from single-crystal X-ray diffraction
Finkelstein, Gregory J.; Dera, Przemyslaw K.; Duffy, Thomas S.
2014-10-29
Synchrotron-based high-pressure single-crystal X-ray diffraction experiments were conducted on ~Mg 0.9Fe 0.1SiO 3 (En 90) orthopyroxene crystals at room temperature to a maximum pressure of 48.5 GPa. The sample was compressed in a diamond anvil cell with a neon pressure medium and a gold pressure calibrant. In addition to the previously described orthopyroxene to β-opx transition (designated HPCEN2 in previous studies), we observe two further phase transitions at 29.9 GPa and 40.3 GPa. However, we do not observe the γ-opx phase recently described in an Fe-rich orthopyroxene composition. The structures of both of the new phases were solved in spacemore » group Pca21. While their Mg-O layers remain pyroxene-like, their Si-O layers transform in a stepwise fashion to akimotoite-like sheets, with sites in 4-, 5-, or 6-fold coordination, depending on the specific structure and layer. Due to the increased Si-O coordination number, we designate the new structures α- and β-post-orthopyroxene (α-popx and β-popx). α-popx has one Si-O layer that is entirely tetrahedral, and one layer that contains both tetrahedra and 5-coordinated Si in distorted square pyramids. β-popx retains the mixed 4- and 5-coordinated Si layer found in α-popx, while the other Si layer adopts fully octahedral coordination. The α- and β-popx structures show a progressive transformation towards the arrangement of Si layers found in akimotoite, a potentially important phase in the earth’s transition zone. Metastable transformations in pyroxenes are of interest for understanding possible metastability in geological environments such as subducting slabs and meteorite impacts« less
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Phase transitions in orthopyroxene (En 90) to 49GPa from single-crystal X-ray diffraction
DOE Office of Scientific and Technical Information (OSTI.GOV)
Finkelstein, Gregory J.; Dera, Przemyslaw K.; Duffy, Thomas S.
Synchrotron-based high-pressure single-crystal X-ray diffraction experiments were conducted on ~Mg 0.9Fe 0.1SiO 3 (En 90) orthopyroxene crystals at room temperature to a maximum pressure of 48.5 GPa. The sample was compressed in a diamond anvil cell with a neon pressure medium and a gold pressure calibrant. In addition to the previously described orthopyroxene to β-opx transition (designated HPCEN2 in previous studies), we observe two further phase transitions at 29.9 GPa and 40.3 GPa. However, we do not observe the γ-opx phase recently described in an Fe-rich orthopyroxene composition. The structures of both of the new phases were solved in spacemore » group Pca21. While their Mg-O layers remain pyroxene-like, their Si-O layers transform in a stepwise fashion to akimotoite-like sheets, with sites in 4-, 5-, or 6-fold coordination, depending on the specific structure and layer. Due to the increased Si-O coordination number, we designate the new structures α- and β-post-orthopyroxene (α-popx and β-popx). α-popx has one Si-O layer that is entirely tetrahedral, and one layer that contains both tetrahedra and 5-coordinated Si in distorted square pyramids. β-popx retains the mixed 4- and 5-coordinated Si layer found in α-popx, while the other Si layer adopts fully octahedral coordination. The α- and β-popx structures show a progressive transformation towards the arrangement of Si layers found in akimotoite, a potentially important phase in the earth’s transition zone. Metastable transformations in pyroxenes are of interest for understanding possible metastability in geological environments such as subducting slabs and meteorite impacts« less
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Romeo, Elizabeth M
2013-01-01
This study was conducted to investigate the predictability of several variables in achieving first-time success on the NCLEX-RN. Several researchers have attempted to investigate the differences between students who passed the NCLEX-RN the first time and those who failed. No studies used a large enough failure group to have statistical significance. The three specific variables in this study were nursing GPA, SAT combined math and verbal scores, and critical thinking measured on a standardized assessment examination. An ex post facto study design was used to examine data from the records of associate degree nursing graduates during a three-year period. The most significant predictors of NCLEX-RN success were the students' nursing GPA and the overall standardized assessment examination score. The findings of this study could potentially influence the identification of students at risk for NCLEX-RN failure.
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Zero-Kelvin Compression Isotherms of the Elements 1 ≤ Z ≤ 92 to 100 GPa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Young, David A.; Cynn, Hyunchae; Söderlind, Per
2016-12-01
Most of the chemical elements have now been compressed close to or above 100 GPa (1 Mbar) pressure in diamond-anvil cells and the pressure–volume room-temperature isotherms have been measured. We collect these data and use simple lattice-dynamics models to reduce the isotherms to 0 K. We have extended the published work by making new diamond-anvil-cell measurements on Cr and Rh, and by conducting density-functional calculations on the elements Po, At, Rn, Fr, Ra, and Ac. The 0 K data are tabulated for all elements 1 ≤ Z ≤ 92 and 0 ≤ P ≤ 100 GPa. These data are usefulmore » for generating wide-range equation of state models and for studying the stability of chemical compounds at high pressure (“Megabar chemistry”). The tables presented here are intended to be reference thermodynamic tables for use in high-pressure research. Further experimental and theoretical work will be needed to extend the tables to higher pressure and to improve accuracy.« less
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High-pressure phases of cordierite from single-crystal X-ray diffraction to 15 GPa
Finkelstein, Gregory J.; Dera, Przemyslaw K.; Duffy, Thomas S.
2015-08-14
High-pressure single-crystal X-ray diffraction experiments were conducted on natural cordierite crystals with composition Mg1.907(18)Fe0.127(6)Al4.01(2)Si4.96(3)Na0.026(3)O18.12(9) using a synchrotron X-ray source. The samples were compressed at 300 K in a diamond anvil cell to a maximum pressure of 15.22(15) GPa with a neon pressure-transmitting medium and a gold pressure calibrant. We observed a recently described orthorhombic to triclinic transition, as well as a further transition to a second triclinic phase. We solved and refined both new triclinic hases in space group P1, and designate them cordierite II and III. The structures of cordierite II and III were refined at 7.52(3) GPa atmore » 15.22(15) GPa, respectively. The lattice parameters at these pressures are a = 15.567(3) Å, b = 9.6235(4) Å, c = 9.0658(6) Å, α = 89.963(5)°, β = 86.252(10)°, and γ = 90.974(8)° for cordierite II, and a = 8.5191(19) Å, b = 8.2448(3) Å, c = 9.1627(4) Å, α = 85.672(4)°, β = 85.986(7)°, and γ = 70.839(10)° for cordierite III. Across the phase transitions there is a significant reduction in the length of the a-axis (~2 Å per phase transition), whereas both the b- and c-axis remain largely unchanged. Cordierite II has four- and five-coordinated Si and Al, while cordierite III has four-, five-, and six-coordinated Si, four- and five-coordinated Al, and five- and six-coordinated Mg. The sequence of high-pressure phases shows increasing polymerization of coordination polyhedra. These results, together with other recent studies, suggest that mixed 4-, 5-, and 6-fold coordination states may occur more commonly in silicate structures compressed at 300 K than previously recognized.« less
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Three-dimensional analysis of facial shape and symmetry in twins using laser surface scanning.
Djordjevic, J; Jadallah, M; Zhurov, A I; Toma, A M; Richmond, S
2013-08-01
Three-dimensional analysis of facial shape and symmetry in twins. Faces of 37 twin pairs [19 monozygotic (MZ) and 18 dizygotic (DZ)] were laser scanned at the age of 15 during a follow-up of the Avon Longitudinal Study of Parents and Children (ALSPAC), South West of England. Facial shape was analysed using two methods: 1) Procrustes analysis of landmark configurations (63 x, y and z coordinates of 21 facial landmarks) and 2) three-dimensional comparisons of facial surfaces within each twin pair. Monozygotic and DZ twins were compared using ellipsoids representing 95% of the variation in landmark configurations and surface-based average faces. Facial symmetry was analysed by superimposing the original and mirror facial images. Both analyses showed greater similarity of facial shape in MZ twins, with lower third being the least similar. Procrustes analysis did not reveal any significant difference in facial landmark configurations of MZ and DZ twins. The average faces of MZ and DZ males were coincident in the forehead, supraorbital and infraorbital ridges, the bridge of the nose and lower lip. In MZ and DZ females, the eyes, supraorbital and infraorbital ridges, philtrum and lower part of the cheeks were coincident. Zygosity did not seem to influence the amount of facial symmetry. Lower facial third was the most asymmetrical. Three-dimensional analyses revealed differences in facial shapes of MZ and DZ twins. The relative contribution of genetic and environmental factors is different for the upper, middle and lower facial thirds. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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Phase relations of aluminous silica to 120 GPa and lowermost mantle dynamics
NASA Astrophysics Data System (ADS)
Tronnes, R. G.; Andrault, D.; Konopkova, Z.; Morgenroth, W.; Liermann, H.-P.
2012-04-01
Basalts have 3-10 times higher concentrations of Al, Ti, Ca and Na and more than 5 times lower concentration of Mg than peridotite. The resulting lower mantle basaltic mineralogy has no ferropericlase and low proportion of Mg-perovskite and post-perovskite with high Fe/Mg-ratio. Oversaturation of silica and alumina produces separate silica-dominated phases and Al-rich phases (NAL and Ca-ferrite phases). At pressures of 60-100 GPa common basalts crystallize 15-20% CaCl2-structured silica, 15-25% Ca-ferrite, 35-40% Mg-perovskite and 20-30% Ca-perovskite. The Fe-rich Mg-perovskite makes basaltic material denser than peridotite throughout the lower mantle below 720 km depth, with important implications for mantle dynamics. Partial separation of subducted basaltic crust from depleted lithosphere may occur within the strongly heterogeneous D" zone. The silica-dominated phases have considerable solubility of alumina [1]. At 3500-4000 K the transition from the CaCl2-phase to seifertite (a-PbO2-structure) of pure SiO2 occurs at 130-140 GPa, with a dp/dT-slope of about 10 MPa/K [2]. The transition pressure is reduced with Al-saturation. We investigated silica with 4 and 6 wt% alumina to 120 GPa, using LH-DAC at the Extreme Conditions Beamline (P02.2) at PETRA-III, DESY. Powdered glass mixed with 10-15 wt% Pt-powder was compressed and heated in NaCl pressure media in Re-gaskets. To delineate the phase transition, the samples were compressed incrementally with intermittent laser heating. Slow reaction rates required 20-40 min heating at 3500-4000 K for each heating step. The XRD data and pressure estimates were acquired repeatedly during heating and after quenching to room temperature. The first crystallization of seifertite at 3500-4000 K was recorded at about 118 and 108 GPa in samples with 4 and 6 wt% AlO1.5, respectively. The CaCl2-structured silica phase crystallized along with seifertite, consistent with a binary phase loop trending towards lower pressure with increasing
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Ar and K partitioning between clinopyroxene and silicate melt to 8 GPa
NASA Astrophysics Data System (ADS)
Chamorro, E. M.; Brooker, R. A.; Wartho, J.-A.; Wood, B. J.; Kelley, S. P.; Blundy, J. D.
2002-02-01
The relative incompatibility of Ar and K are fundamental parameters in understanding the degassing history of the mantle. Clinopyroxene is the main host for K in most of the upper mantle, playing an important role in controlling the K/Ar ratio of residual mantle and the subsequent time-integrated evolution of 40Ar/36Ar ratios. Clinopyroxene also contributes to the bulk Ar partition coefficient that controls the Ar degassing rate during mantle melting. The partitioning of Ar and K between clinopyroxene and quenched silicate melt has been experimentally determined from 1 to 8 GPa for the bulk compositions Ab80Di20 (80 mol% albite-20 mol% diopside) and Ab20Di80 with an ultraviolet laser ablation microprobe (UVLAMP) technique for Ar analysis and the ion microprobe for K. Data for Kr (UVLAMP) and Rb (ion probe) have also been determined to evaluate the role of crystal lattice sites in controlling partitioning. By excluding crystal analyses that show evidence of glass contamination, we find relatively constant Ar partition coefficients (DAr) of 2.6 × 10-4 to 3.9 × 10-4 for the Ab80Di20 system at pressures from 2 to 8 GPa. In the Ab20Di80 system, DAr shows similar low values of 7.0 × 10-5 and 3.0 × 10-4 at 1 to 3 GPa. All these values are several orders of magnitude lower than previous measurements on separated crystal-glass pairs. DK is 10 to 50 times greater than DRb for all experiments, and both elements follow parallel trends with increasing pressure, although these trends are significantly different in each system studied. The DK values for clinopyroxene are at least an order of magnitude greater than DAr under all conditions investigated here, but DAr appears to show more consistent behavior between the two systems than K or Rb. The partitioning behavior of K and Rb can be explained in terms of combined pressure, temperature, and crystal chemistry effects that result in changes for the size of the clinopyroxene M2 site. In the Ab20Di80 system, where
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Sound velocity of 23 Å phase (a new Al-bearing hydrous Mg-silicate) to 14 GPa
NASA Astrophysics Data System (ADS)
Cai, N.; Chen, T.; Qi, X.; Inoue, T.; Li, B.
2016-12-01
Dense hydrous phases are believed to play an important role in transporting water back into the deep interior of the Earth. Recently, a new Al-bearing hydrous Mg-silicate named 23 Å phase (ideal composition Mg11Al2Si4O16(OH)12) was reported (Cai et al., 2015), which could be a very important hydrous phase in subducting slab. Here for the first time we measured the compressional and shear wave velocities of this new hydrous phase under mantle pressures. The sample was synthesized at 10 GPa and 1000 ºC using the chemical mixture of stoichiometric as starting materials. The recovered sample was then crushed into fine powder and hot pressed at 10 GPa and 900 ºC for 3 hours. X-ray diffraction, density measurement, and SEM characterization indicated that the specimen is nearly a pure phase, 20 µm in grain size, with a bulk density of 3.004 g/cm3. The acoustic measurements were conducted in a 1000-ton uniaxial split-cylinder multi-anvil apparatus using ultrasonic interferometry techniques (Li et al., 1996) up to 14 GPa at room temperature. The pressures were determined in situ by using alumina buffer rod as a pressure marker (Wang et al., 2015). A dual-mode piezoelectric transducer enables us to measure P and S wave travel times simultaneously, which in turn allows for a precise determination of the sound velocities and elastic bulk and shear moduli at high pressures. Preliminary results suggest that the velocities, (especially for S wave) of this 23 Å phase are slower than that of phase A and most of the mantle minerals. These results may have important implications for understanding some localized low velocity zones in subduction zones. Cai, N., T. Inoue, K. Fujino, H. Ohfuji and H. Yurimoto (2015) A Possible New Al-bearing Hydrous Mg-silicate (23 Å phase) in the Deep Upper Mantle. Am Mineral. 100: 2330-2335. Li, B., I. Jackson, T. Gasparik, and R. C. Liebermann (1996), Elastic wave velocity measurement in multianvil apparatus to 10 GPa using ultrasonic
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Di Paola-Naranjo, Romina D; Baroni, Maria V; Podio, Natalia S; Rubinstein, Hector R; Fabani, Maria P; Badini, Raul G; Inga, Marcela; Ostera, Hector A; Cagnoni, Mariana; Gallegos, Ernesto; Gautier, Eduardo; Peral-Garcia, Pilar; Hoogewerff, Jurian; Wunderlin, Daniel A
2011-07-27
Our main goal was to investigate if robust chemical fingerprints could be developed for three Argentinean red wines based on organic, inorganic, and isotopic patterns, in relation to the regional soil composition. Soils and wines from three regions (Mendoza, San Juan, and Córdoba) and three varieties (Cabernet Sauvignon, Malbec, and Syrah) were collected. The phenolic profile was determined by HPLC-MS/MS and multielemental composition by ICP-MS; (87)Sr/(86)Sr and δ(13)C were determined by TIMS and IRMS, respectively. Chemometrics allowed robust differentiation between regions, wine varieties, and the same variety from different regions. Among phenolic compounds, resveratrol concentration was the most useful marker for wine differentiation, whereas Mg, K/Rb, Ca/Sr, and (87)Sr/(86)Sr were the main inorganic and isotopic parameters selected. Generalized Procrustes analysis (GPA) using two studied matrices (wine and soil) shows consensus between them and clear differences between studied areas. Finally, we applied a canonical correlation analysis, demonstrating significant correlation (r = 0.99; p < 0.001) between soil and wine composition. To our knowledge this is the first report combining independent variables, constructing a fingerprint including elemental composition, isotopic, and polyphenol patterns to differentiate wines, matching part of this fingerprint with the soil provenance.
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ERIC Educational Resources Information Center
Johnson, James
2013-01-01
In an effort to standardize academic risk assessment, the NCAA developed the graduation risk overview (GRO) model. Although this model was designed to assess graduation risk, its ability to predict grade-point average (GPA) remained unknown. Therefore, 134 individual risk assessments were made to determine GRO model effectiveness in the…
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Volatile compounds of sulfur in the Fe-C-S system at 5.3 GPa and 1300°C
NASA Astrophysics Data System (ADS)
Zhimulev, E. I.; Sonin, V. M.; Bul'bak, T. A.; Chepurov, A. I.; Tomilenko, A. A.; Pokhilenko, N. P.
2015-05-01
This report presents the results of experimental studies of the fluid phase in the Fe-C-S system at high P and T values (5.3 GPa and 1300°C) conforming to diamond synthesis. The samples for experiments were mounted on air; therefore, the volatile compounds detected after the experiments are characterized by a wide variety and complicated composition involving both inorganic and organic components. Among the inorganic compounds, CO2, H2O, N2, SO2, CS2, and COS were detected. The GC/MS analysis revealed hydrocarbons (paraffins, olefins, and arenes), including high-molecular compounds. The formation of heavy hydrocarbons confirms their thermodynamic stability under high pressure. Oxygenated hydrocarbons (alcohols, aldehydes, ketones, carboxylic acids, and ethers) were also detected.
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NASA Astrophysics Data System (ADS)
Ghiorso, M. S.; Cutler, I.; Nevins, D.; Spera, F. J.
2009-12-01
Equilibrium Molecular Dynamics (MD) simulations are applied to molten CaAl2Si2O8 using a Coulomb-Born-Mayer-van der Waals pair potential form and parameters from Matsui (1996, GRL 23:395). Experiments were performed in the microcanonical ensemble (NEV) using 8000 atoms, a 1 fs time step, and simulation durations of 50 ps. Computations were carried out every 500 K over a temperature range of 2500 - 5000 K along 21 isochores to yield a grid of 141 state points spanning the pressure range 0-800 GPa. Atomic coordination statistics are determined by counting nearest neighbor configurations up to a cutoff distance defined by the first minima of the pair correlation function. A thermodynamic model (and EOS) for this liquid is developed from the MD simulation results by combining the Rosenfeld-Tarazona (1998, Mol Phys 95:141) potential energy-temperature scaling law with the Universal EOS (1986, J Phys C, 19:L467). The resulting model is used to estimate thermodynamic properties and the sound speed of the liquid near zero pressure and these compare favorably to physical experiments. By contrast to our previous work (DOI: 10.1016/j.gca.2009.08.012), which utilized an alternate pair potential, no structural phase transition is required to thermodynamically model these results — a single parameterization describes the properties of the system over the entire range of ~4-fold compression. Our analysis indicates the existence of polyamorphism with a critical point at ~0.6 GPa and ~3000 K. A modeled Hugoniot is consistent with the low-pressure shock experiments of Rigden et al. (JGR 94:9508) but inconsistent with the more recent measurements of Asimow and Ahrens (EOS 89,MR32B-04). The latter experiments are matched with a model isentrope emanating from just above the zero pressure melting point of anorthite, which also coincides with the initial conditions of the shock. The MD simulations reveal that near zero-pressure, CaAl2Si2O8 liquid is dominated by Si in tetrahedral
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Muramatsu, Takaki; Gasparov, Lev V.; Berger, Helmuth
2016-04-07
We measured the pressure dependence of electrical resistance of single-crystal magnetite (Fe 3O 4) under quasi-hydrostatic conditions to 100 GPa using low-temperature, megabar diamond-anvil cell techniques in order to gain insight into the anomalous behavior of this material that has been reported over the years in different high-pressure experiments. The measurements under nearly hydrostatic pressure conditions allowed us to detect the clear Verwey transition and the high-pressure structural phase. Furthermore, the appearance of a metallic ground state after the suppression of the Verwey transition around 20 GPa and the concomitant enhancement of electrical resistance caused by the structural transformation tomore » the high-pressure phase form reentrant semiconducting-metallic-semiconducting behavior, though the appearance of the metallic phase is highly sensitive to stress conditions and details of the measurement technique.« less
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NASA Astrophysics Data System (ADS)
Kuriakose, Maju; Raetz, Samuel; Hu, Qing Miao; Nikitin, Sergey M.; Chigarev, Nikolay; Tournat, Vincent; Bulou, Alain; Lomonosov, Alexey; Djemia, Philippe; Gusev, Vitalyi E.; Zerr, Andreas
2017-10-01
Water ice is a molecular solid whose behavior under compression reveals the interplay of covalent bonding in molecules and forces acting between them. This interplay determines high-pressure phase transitions, the elastic and plastic behavior of H2O ice, which are the properties needed for modeling the convection and internal structure of the giant planets and moons of the solar system as well as H2O -rich exoplanets. We investigated experimentally and theoretically elastic properties and phase transitions of cubic H2O ice at room temperature and high pressures between 10 and 82 GPa. The time-domain Brillouin scattering (TDBS) technique was used to measure longitudinal sound velocities (VL) in polycrystalline ice samples compressed in a diamond anvil cell. The high spatial resolution of the TDBS technique revealed variations of VL caused by elastic anisotropy, allowing us to reliably determine the fastest and the slowest sound velocity in a single crystal of cubic H2O ice and thus to evaluate existing equations of state. Pressure dependencies of the single-crystal elastic moduli Ci j(P ) of cubic H2O ice to 82 GPa have been obtained which indicate its hardness and brittleness. These results were compared with ab initio calculations. It is suggested that the transition from molecular ice VII to ionic ice X occurs at much higher pressures than proposed earlier, probably above 80 GPa.
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NASA Astrophysics Data System (ADS)
Pittman, E. R.; Gustavsen, R. L.; Hagelberg, C. R.; Schmidt, J. H.
2017-06-01
The focus of this set of experiments is the development of data on the Hugoniot for the overdriven products equation of state (EOS) of PBX 9501 (95 weight % HMX, 5 weight % plastic binder) and to extend data from which current computational EOS models draw. This series of shots was conducted using the two-stage gas-guns at Los Alamos and aimed to gather data in the 30 to 120 GPa pressure regime. Experiments were simulated using FLAG, a Langrangian multiphysics code, using a one-dimensional setup which employs the Wescott Stewart Davis (WSD) reactive burn model. Prior to this study, data did not extend above 90 GPa, so the new data allowed the model to be re-evaluated. A comparison of the simulations with the experimental data shows that the model fits well below 80 GPa. However, the model did not fall within the error bars of the data for higher pressures. This is an indication that the PBX 9501 overdriven EOS products model could be modified to better match the data.
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Are SSATs and GPA Enough? A Theory-Based Approach to Predicting Academic Success in Secondary School
ERIC Educational Resources Information Center
Grigorenko, Elena L.; Jarvin, Linda; Diffley, Ray; Goodyear, Julie; Shanahan, Edward J.; Sternberg, Robert J.
2009-01-01
Two studies were carried out to predict academic success in the highly competitive environment of a private preparatory school, Choate Rosemary Hall. The 1st study focused on the question of whether there are indicators beyond middle school grade-point average (GPA) and standardized test scores that might enhance the validity of measures for…
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ERIC Educational Resources Information Center
Jung, Kyoung Rae
2013-01-01
Drawing upon self-efficacy theory (Bandura, 1997), the purpose of this study was to examine academic self-discipline (ASD) as a mediator of the relationship between academic self-efficacy (ASE) and college GPA, as well as the feedback effect of previous academic performance on subsequent ASE and ASD. To test this research question, I used…
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Equation of state of pyrite to 85 GPa and 2400 K
NASA Astrophysics Data System (ADS)
Thompson, E. C.; Chidester, B.; Campbell, A. J.; Prakapenka, V.
2014-12-01
Pyrite (FeS2), a Pa3 space group non-magnetic semiconductor, is the most abundant iron sulfide in nature, yet the high cosmic abundance of sulfur is not reflected in the terrestrial crust, implying it is either sequestered in the Earth's interior or was volatilized during accretion. As it has widely been suggested that sulfur could be one of the contributing light elements leading to the density deficit of Earth's core, a robust thermal equation of state of FeS2 is vital for understanding the evolution and properties of Earth's interior. We performed X-ray diffraction measurements on FeS2 at the GSECARS sector 13-ID-D and HPCAT sector 16-ID-B beamlines at the Advanced Photon Source. Pressures from 17 to 85 GPa and temperatures up to 2400 K were achieved using laser-heated diamond anvil cells. Pressures were determined from the lattice parameters of KBr [1], which served as an insulator and pressure medium, and temperatures were determined by spectroradiometry. No phase transitions were observed in the pyrite structure over the pressure and temperature ranges investigated. By combining our new P-V-T data with previously published room temperature compression data [2], we have determined a thermal equation of state for FeS2, with bulk modulus K=182.6(74) GPa, pressure derivative K'=3.82(25), and αKT=0.00329(45). Our revised equation of state for pyrite is consistent with a core density deficit satisfied by 9-10 wt.% sulfur. We compare these findings to previously published ab intio equation of state parameters for pyrite under a similar range of pressures [3]. [1] Fischer et al. (2012) EPSL 357-358, 268-276. [2] Merkel et al. (2002) PCM 29, 1-9. [3] Le Page and Rodgers (2005) PCM 32, 564-567.
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Albanese, Mark A; Farrell, Philip; Dottl, Susan L
2005-01-01
Using Medical College Admission Test-grade point average (MCAT-GPA) scores as a threshold has the potential to address issues raised in recent Supreme Court cases, but it introduces complicated methodological issues for medical school admissions. To assess various statistical indexes to determine optimally discriminating thresholds for MCAT-GPA scores. Entering classes from 1992 through 1998 (N = 752) are used to develop guidelines for cut scores that optimize discrimination between students who pass and do not pass the United States Medical Licensing Examination (USMLE) Step 1 on the first attempt. Risk differences, odds ratios, sensitivity, and specificity discriminated best for setting thresholds. Compensatory versus noncompensatory procedures both accounted for 54% of Step 1 failures, but demanded different performance requirements (noncompensatory MCAT-biological sciences = 8, physical sciences = 7, verbal reasoning = 7--sum of scores = 22; compensatory MCAT total = 24). Rational and defensible intellectual achievement thresholds that are likely to comply with recent Supreme Court decisions can be set from MCAT scores and GPAs.
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Elion, Audrey A; Wang, Kenneth T; Slaney, Robert B; French, Bryana H
2012-04-01
This study examined 219 African American college students at predominantly White universities using the constructs of perfectionism, academic achievement, self-esteem, depression, and racial identity. Cluster analysis was performed using the Almost Perfect Scale-Revised (APS-R), which yielded three clusters that represented adaptive perfectionists, maladaptive perfectionists, and nonperfectionists. These three groups were compared on their scores on the Rosenberg Self-Esteem Scale (RSES), the Center for Epidemiological Studies-Depression Scale (CES-D), the Cross Racial Identity Scale (CRIS), and Grade Point Average (GPA). Adaptive perfectionists reported higher self-esteem and lower depression scores than both the nonperfectionists and maladaptive perfectionists. Adaptive perfectionists had higher GPAs than nonperfectionists. On the racial identity scales, maladaptive perfectionists had higher scores on Pre-Encounter Self Hatred and Immersion-Emersion Anti-White subscales than adaptive perfectionists. The cultural and counseling implications of this study are discussed and integrated. Finally, recommendations are made for future studies of African American college students and perfectionism. PsycINFO Database Record (c) 2012 APA, all rights reserved.
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Bista, S; Stebbins, Jonathan; Hankins, William B.; Sisson, Thomas W.
2015-01-01
In the pressure range in the Earth’s mantle where many basaltic magmas are generated (1 to 3 GPa) (Stolper et al. 1981), increases in the coordination numbers of the network-forming cations in aluminosilicate melts have generally been considered to be minor, although effects on silicon and particularly on aluminum coordination in non-bridging oxygen-rich glasses from the higher, 5 to 12 GPa range, are now well known. Most high-precision measurements of network cation coordination in such samples have been made by spectroscopy (notably 27Al and 29Si NMR) on glasses quenched from high-temperature, high-pressure melts synthesized in solid-media apparatuses and decompressed to room temperature and 1 bar pressure. There are several effects that could lead to the underestimation of the extent of actual structural (and density) changes in high-pressure/temperature melts from such data. For non-bridging oxygen-rich sodium and calcium aluminosilicate compositions in the 1 to 3 GPa range, we show here that glasses annealed near to their glass transition temperatures systematically record higher recovered increases in aluminum coordination and in density than samples quenched from high-temperature melts. In the piston-cylinder apparatus used, rates of cooling through the glass transition are measured as very similar for both higher and lower initial temperatures, indicating that fictive temperature effects are not the likely explanation of these differences. Instead, transient decreases in melt pressure during thermal quenching, which may be especially large for high initial run temperatures, of as much as 0.5 to 1 GPa, may be responsible. As a result, the equilibrium proportion of high-coordinated Al in this pressure range may be 50 to 90% greater than previously estimated, reaching mean coordination numbers (e.g., 4.5) that are probably high enough to significantly affect melt properties. New data on jadeite (NaAlSi2O6) glass confirm that aluminum coordination increase
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NASA Astrophysics Data System (ADS)
Gudfinnsson, Gudmundur H.; Presnall, Dean C.
1996-12-01
Isobarically invariant phase relations in the CaO-MgO-Al2O3-SiO2 system (CMAS) involving the lherzolite phase assemblage in equilibrium with liquid have been determined at 2.4-3.4 GPa. These phase relations form the solidus of model lherzolite in the CMAS system. Our data, which include determinations of all phase compositions, are in excellent agreement with the 3.0 and 4.0 GPa points of Milholland and Presnall [1991] and Davis and Schairer [1965], respectively. The invariant transition on the P-T solidus curve from spinel- to garnet-lherzolite at 3.0 GPa, 1575°C [Milholland and Presnall, 1991], is confirmed, but we observe that the theoretically required temperature depression on the solidus curve at this point is not experimentally detectable. Composition trends along the solidus take a sharp turn at the transition. In the spinel-lherzolite stability field, melt compositions become increasingly Fo-normative and less En-normative with increasing pressure, but become less Fo-normative and more pyroxenitic as pressure increases in the garnet-lherzolite stability field. Calculated melting reactions indicate that forsterite is in reaction relationship with the melt up to 3.0 GPa. Orthopyroxene is also in reaction relationship at pressures higher than just over 2.8 GPa and is the only phase in reaction relationship with the melt in the garnet-lherzolite stability field. Comparison of the normative compositions and the CaO/Al2O3 values of the komatiites of Gorgona Island and of the Reliance Formation in Zimbabwe with the compositions of liquids along the solidus of model lherzolite in the CMAS system indicates that the former komatiites were generated at pressures close to 3.7 GPa and the latter at close to 4.5 GPa, assuming that the melt generation occurred in the presence of the complete garnet-lherzolite assemblage.
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NASA Astrophysics Data System (ADS)
Likhacheva, A. Yu.; Dementiev, S. N.; Goryainov, S. V.
2017-08-01
The elastic and structure behavior of natural thaumasite compressed in methanol-ethanol-H2O up to 5 GPa was studied by synchrotron powder diffraction with a diamond anvil cell. In the pressure range between 0.0001 and 4.5 GPa, the compression is regular and slightly anisotropic, with a more rigid ab-plane coinciding with the orientation of hydrogen bonds and S-O, C-O bonds in anion groups. The corresponding bulk moduli derived from the third-order Birch-Murnaghan EoS fit are K a = 43(2), K c = 35(2), K T = 39(2) GPa. Rietveld refinements reveal some general features of the structure evolution of thaumasite, which are consistent with the observed elastic anisotropy. The compression within the ab-plane proceeds mainly at the expense of shortening of hydrogen bonds and much lesser decrease of C-O and S-O bonds. In the range of 0.0001-3 GPa the Ca-O polyhedra contract more rapidly along the c-axis as compared to the ab-plane. At about 5 GPa, thaumasite undergoes a reversible transformation to an amorphous phase. The observed behavior differs drastically with that studied previously using helium as the pressure medium, which suggests the effect of He penetration increasing the structure stiffness. Without helium support, the thaumasite structure is preserved only up to 4.5 GPa.
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Evaluation of Visual Field Progression in Glaucoma: Quasar Regression Program and Event Analysis.
Díaz-Alemán, Valentín T; González-Hernández, Marta; Perera-Sanz, Daniel; Armas-Domínguez, Karintia
2016-01-01
To determine the sensitivity, specificity and agreement between the Quasar program, glaucoma progression analysis (GPA II) event analysis and expert opinion in the detection of glaucomatous progression. The Quasar program is based on linear regression analysis of both mean defect (MD) and pattern standard deviation (PSD). Each series of visual fields was evaluated by three methods; Quasar, GPA II and four experts. The sensitivity, specificity and agreement (kappa) for each method was calculated, using expert opinion as the reference standard. The study included 439 SITA Standard visual fields of 56 eyes of 42 patients, with a mean of 7.8 ± 0.8 visual fields per eye. When suspected cases of progression were considered stable, sensitivity and specificity of Quasar, GPA II and the experts were 86.6% and 70.7%, 26.6% and 95.1%, and 86.6% and 92.6% respectively. When suspected cases of progression were considered as progressing, sensitivity and specificity of Quasar, GPA II and the experts were 79.1% and 81.2%, 45.8% and 90.6%, and 85.4% and 90.6% respectively. The agreement between Quasar and GPA II when suspected cases were considered stable or progressing was 0.03 and 0.28 respectively. The degree of agreement between Quasar and the experts when suspected cases were considered stable or progressing was 0.472 and 0.507. The degree of agreement between GPA II and the experts when suspected cases were considered stable or progressing was 0.262 and 0.342. The combination of MD and PSD regression analysis in the Quasar program showed better agreement with the experts and higher sensitivity than GPA II.
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A parametric ribcage geometry model accounting for variations among the adult population.
Wang, Yulong; Cao, Libo; Bai, Zhonghao; Reed, Matthew P; Rupp, Jonathan D; Hoff, Carrie N; Hu, Jingwen
2016-09-06
The objective of this study is to develop a parametric ribcage model that can account for morphological variations among the adult population. Ribcage geometries, including 12 pair of ribs, sternum, and thoracic spine, were collected from CT scans of 101 adult subjects through image segmentation, landmark identification (1016 for each subject), symmetry adjustment, and template mesh mapping (26,180 elements for each subject). Generalized procrustes analysis (GPA), principal component analysis (PCA), and regression analysis were used to develop a parametric ribcage model, which can predict nodal locations of the template mesh according to age, sex, height, and body mass index (BMI). Two regression models, a quadratic model for estimating the ribcage size and a linear model for estimating the ribcage shape, were developed. The results showed that the ribcage size was dominated by the height (p=0.000) and age-sex-interaction (p=0.007) and the ribcage shape was significantly affected by the age (p=0.0005), sex (p=0.0002), height (p=0.0064) and BMI (p=0.0000). Along with proper assignment of cortical bone thickness, material properties and failure properties, this parametric ribcage model can directly serve as the mesh of finite element ribcage models for quantifying effects of human characteristics on thoracic injury risks. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Investigating the sex-related geometric variation of the human cranium.
Bertsatos, Andreas; Papageorgopoulou, Christina; Valakos, Efstratios; Chovalopoulou, Maria-Eleni
2018-01-29
Accurate sexing methods are of great importance in forensic anthropology since sex assessment is among the principal tasks when examining human skeletal remains. The present study explores a novel approach in assessing the most accurate metric traits of the human cranium for sex estimation based on 80 ectocranial landmarks from 176 modern individuals of known age and sex from the Athens Collection. The purpose of the study is to identify those distance and angle measurements that can be most effectively used in sex assessment. Three-dimensional landmark coordinates were digitized with a Microscribe 3DX and analyzed in GNU Octave. An iterative linear discriminant analysis of all possible combinations of landmarks was performed for each unique set of the 3160 distances and 246,480 angles. Cross-validated correct classification as well as multivariate DFA on top performing variables reported 13 craniometric distances with over 85% classification accuracy, 7 angles over 78%, as well as certain multivariate combinations yielding over 95%. Linear regression of these variables with the centroid size was used to assess their relation to the size of the cranium. In contrast to the use of generalized procrustes analysis (GPA) and principal component analysis (PCA), which constitute the common analytical work flow for such data, our method, although computational intensive, produced easily applicable discriminant functions of high accuracy, while at the same time explored the maximum of cranial variability.
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40 CFR 80.216 - What standards apply to gasoline produced or imported for use in the GPA?
Code of Federal Regulations, 2012 CFR
2012-07-01
... 40 Protection of Environment 17 2012-07-01 2012-07-01 false What standards apply to gasoline... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.216 What standards apply to gasoline produced or imported for use in the GPA...
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40 CFR 80.216 - What standards apply to gasoline produced or imported for use in the GPA?
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 16 2010-07-01 2010-07-01 false What standards apply to gasoline... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.216 What standards apply to gasoline produced or imported for use in the GPA...
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40 CFR 80.216 - What standards apply to gasoline produced or imported for use in the GPA?
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 17 2014-07-01 2014-07-01 false What standards apply to gasoline... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.216 What standards apply to gasoline produced or imported for use in the GPA...
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40 CFR 80.216 - What standards apply to gasoline produced or imported for use in the GPA?
Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 17 2013-07-01 2013-07-01 false What standards apply to gasoline... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.216 What standards apply to gasoline produced or imported for use in the GPA...
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40 CFR 80.216 - What standards apply to gasoline produced or imported for use in the GPA?
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 16 2011-07-01 2011-07-01 false What standards apply to gasoline... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Geographic Phase-in Program § 80.216 What standards apply to gasoline produced or imported for use in the GPA...
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ERIC Educational Resources Information Center
Grzimek, Volker; Marks, Melanie Beth; Kinnamon, Eric
2014-01-01
Using survey data the authors investigate the impact of grade point average (GPA) on students' preferences for classroom group work and its structure. Topics range from general attitudes and beliefs (benefits to grades, impact on mastery of material, professors' motives) to administration (group composition, grading, peer reviews, group…
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Metallic hydrogen with a strong electron-phonon interaction at a pressure of 300-500 GPa
NASA Astrophysics Data System (ADS)
Degtyarenko, N. N.; Mazur, E. A.; Grishakov, K. S.
2017-08-01
Atomic metallic hydrogen with a lattice with FDDD symmetry is shown to have a stable phase under hydrostatic compression pressure in the range of 350-500 GPа. The resulting structure has a stable spectrum regarding the collapse of the phonons. Ab-unitio simulation method has been used to calculate the structural, electronic, phononic and other characteristics of the normal metallic phase of the hydrogen at a pressure of 350-500 GPA.
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NASA Astrophysics Data System (ADS)
Poli, S.
2013-12-01
Current knowledge on the solidus temperature for carbonate-bearing rocks suggests that carbonatitic liquids should not form in a subducted oceanic lithosphere, unless anomalous thermal relaxation occurs. For a mildly warm subduction path, COH-bearing basaltic eclogites are expected to loose all H2O component at epidote breakdown, located at approx. 2.8-3.0 GPa. Above this pressure limit, the solidus is that of a carbonated basaltic eclogite which shows a minimum temperature of 1020 °C at 4.0-4.5 GPa (Dasgupta et al. 2004). However, the oceanic crust includes a range of gabbroic rocks, altered on rifts and transforms, with large amounts of An-rich plagioclase. It has been shown that epidote disappearance with pressure depend on the normative anorthite content of the bulk composition considered (Poli et al. 2009); we therefore expect that altered gabbros might display a much wider pressure range where epidote persists, potentially affecting the solidus relationships. Notably, this applies to epidosite rocks formed in hydrothermal environments at oceanic settings, then recovered in high-pressure and ultra-high pressure terrains. New experimental data from 3.7 to 4.6 GPa, 750°C to 1000 °C are intended to unravel the effect of variable bulk and volatile compositions in model eclogites, enriched in the normative anorthite component (An37 and An45). Experiments are performed in piston cylinder and multianvil machines apparatus, using both single and, buffered, double capsule techniques. Garnet, clinopyroxene and coesite form in all syntheses. Lawsonite was found to persist at 3.7 GPa, 750 °C, with both dolomite and magnesite; at 3.8 GPa, 775-800 °C, fluid saturated conditions, epidote coexists with kyanite, dolomite and magnesite. The anhydrous assemblage garnet, omphacite, aragonite, kyanite is found at 4.2 GPa, 850 °C. At 900 °C, fluid-rich conditions, a silicate fluid/melt of granitoid composition, a carbonatitic melt and Na-carbonate are observed. Close to
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ERIC Educational Resources Information Center
Parker, Eugene T., III.; Kilgo, Cindy A.; Sheets, Jessica K. Ezell; Pascarella, Ernest T.
2016-01-01
The purpose of this study is to explore the effects of internship participation on college students, specifically the effect on college GPA. Further, because of the capacity to disaggregate students by race in the sample, this study is significant because it provides much needed empirical evidence surrounding the impact of participation in…
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Hilliard, Massimo A; Bergamasco, Carmela; Arbucci, Salvatore; Plasterk, Ronald HA; Bazzicalupo, Paolo
2004-01-01
An animal's ability to detect and avoid toxic compounds in the environment is crucial for survival. We show that the nematode Caenorhabditis elegans avoids many water-soluble substances that are toxic and that taste bitter to humans. We have used laser ablation and a genetic cell rescue strategy to identify sensory neurons involved in the avoidance of the bitter substance quinine, and found that ASH, a polymodal nociceptive neuron that senses many aversive stimuli, is the principal player in this response. Two G protein α subunits GPA-3 and ODR-3, expressed in ASH and in different, nonoverlapping sets of sensory neurons, are necessary for the response to quinine, although the effect of odr-3 can only be appreciated in the absence of gpa-3. We identified and cloned a new gene, qui-1, necessary for quinine and SDS avoidance. qui-1 codes for a novel protein with WD-40 domains and which is expressed in the avoidance sensory neurons ASH and ADL. PMID:14988722
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ERIC Educational Resources Information Center
Rohr, Samuel L.
2013-01-01
This study examined the relationship between various admissions selection criteria utilized by a small, Liberal Arts College in Indiana. More specifically, the study examined if a higher college preparatory GPA and a higher aggregate score on the SAT helped predict the retention of science, technology, engineering, mathematics, and business…
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Asthenospheric kimberlites: Volatile contents and bulk compositions at 7 GPa
NASA Astrophysics Data System (ADS)
Stamm, Natalia; Schmidt, Max W.
2017-09-01
During ascent, kimberlites react with the lithospheric mantle, entrain and assimilate xenolithic material, loose volatiles and suffer from syn- and post-magmatic alteration. Consequently, kimberlite rocks deviate heavily from their primary melt. Experiments at 7 GPa, 1300-1480 °C, 10-30 wt% CO2 and 0.46 wt% H2O on a proposed primitive composition from the Jericho kimberlite show that saturation with a lherzolitic mineral assemblage occurs only at 1300-1350 °C for a carbonatitic melt with <8 wt% SiO2 and >35 wt% CO2. At asthenospheric temperatures of >1400 °C, where the Jericho melt stays kimberlitic, this composition saturates only in low-Ca pyroxene, garnet and partly olivine. We hence forced the primitive Jericho kimberlite into multiple saturation with a lherzolitic assemblage by adding a compound peridotite. Saturation in olivine, low- and high-Ca pyroxene and garnet was obtained at 1400-1650 °C (7 GPa), melts are kimberlitic with 18-29 wt% SiO2 + Al2O3, 22.1-24.6 wt% MgO, 15-27 wt% CO2 and 0.4-7.1 wt% H2O; with a trade-off of H2O vs. CO2 and temperature. Melts in equilibrium with high-Ca pyroxene with typical mantle compositions have ≥2.5 wt% Na2O, much higher than the commonly proposed 0.1-0.2 wt%. The experiments allow for a model of kimberlite origin in the convective upper mantle, which only requires mantle upwelling that causes melting at the depth where elemental carbon (in metal, diamond or carbide) converts to CO2 (at ∼250 km). If primary melts leading to kimberlites contain a few wt% H2O, then adiabatic temperatures of 1400-1500 °C would yield asthenospheric mantle melts that are kimberlitic (>18 wt% SiO2 + Al2O3) but not carbonatitic (<10 wt% SiO2 + Al2O3) in composition, carbonatites only forming 100-200 °C below the adiabat. These kimberlites represent small melt fractions concentrating CO2 and H2O and then acquire part of their chemical signature by assimilation/fractionation during ascent in the subcratonic lithosphere.
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NASA Astrophysics Data System (ADS)
Watson, H. C.; Watson, B.
2002-05-01
Preliminary results for diffusion of siderophile elements (Cu, Pd, Re, Os, and Mo) in an iron meteorite analog were obtained at temperatures ranging from 1175° C to 1400° C and 1GPa from diffusion couple experiments in a piston-cylinder apparatus. Alloys were prepared by synthesizing mixtures of pure metal powders. The alloys were made from a 90 wt% Fe and 10 wt% Ni base mixture, and approximately 1wt% of the various siderophile elements was added (individually) to the same base mixture to make the doped alloys. The powders were packed in pre-drilled holes ( ~1 mm diameter by 8 mm deep) in MgO cylinders, and run in a piston cylinder apparatus at 1400° C and 1GPa for 48 hours. The resulting homogeneous alloys were then sectioned into wafers approximately 1mm thick, and the faces were polished to prepare for the diffusion experiments. A diffusion couple experiment was conducted by mating a pure alloy wafer and a doped wafer, and placing the couple into an MgO capsule for pressurization and heating in the piston cylinder. The duration of the diffusion experiments ranged from 12 hours to 100 hours. Upon run completion, the diffusion couples were extracted, sectioned lengthwise, and polished for analysis. Diffusion profiles were measured using standard electron microprobe techniques. Preliminary Arrhenius relations have been found as follows: DMo=2.12E-1+/-0.20 m2/s exp(390.86+/-40.46 kJ/mol/RT) DCu=1.37E-3+/-1.25E-3 m2/s exp(315.24+/-31.64 kJ/mol/RT) DPd=2.40E-5+/-2.40E-5 m2/s exp(269.64+/-87.49 kJ/mol/RT) Diffusion coefficients have also been found for Re and Os at 1325° C. They are: DRe=7.89E-15+/-6.70 m2/s and DOs=9.69E-15+/-8.24 m2/s
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Equation of state of pyrite to 80 GPa and 2400 K
Thompson, Elizabeth C.; Chidester, Bethany A.; Fischer, Rebecca A.; ...
2016-05-02
The high-cosmic abundance of sulfur is not reflected in the terrestrial crust, implying it is either sequestered in the Earth’s interior or was volatilized during accretion. As it has widely been suggested that sulfur could be one of the contributing light elements leading to the density deficit of Earth’s core, a robust thermal equation of state of iron sulfide is useful for understanding the evolution and properties of Earth’s interior. We performed X-ray diffraction measurements on FeS 2 achieving pressures from 15 to 80 GPa and temperatures up to 2400 K using laser-heated diamond-anvil cells. No phase transitions were observedmore » in the pyrite structure over the pressure and temperature ranges investigated. Combining our new P-V-T data with previously published room-temperature compression and thermochemical data, we fit a Debye temperature of 624(14) K and determined a Mie-Grüneisen equation of state for pyrite having bulk modulus K T = 141.2(18) GPa, pressure derivative K' T = 5.56(24), Grüneisen parameter γ 0 = 1.41, anharmonic coefficient A 2 = 2.53(27) × 10 –3 J/(K 2·mol), and q = 2.06(27). These findings are compared to previously published equation of state parameters for pyrite from static compression, shock compression, and ab initio studies. This revised equation of state for pyrite is consistent with an outer core density deficit satisfied by 11.4(10) wt% sulfur, yet matching the bulk sound speed of PREM requires an outer core composition of 4.8(19) wt% S. Here, this discrepancy suggests that sulfur alone cannot satisfy both seismological constraints simultaneously and cannot be the only light element within Earth’s core, and so the sulfur content needed to satisfy density constraints using our FeS 2 equation of state should be considered an upper bound for sulfur in the Earth’s core.« less
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NASA Astrophysics Data System (ADS)
Collinet, Max; Médard, Etienne; Charlier, Bernard; Vander Auwera, Jacqueline; Grove, Timothy L.
2015-10-01
We have performed piston-cylinder experiments on a primitive martian mantle composition between 0.5 and 2.2 GPa and 1160 to 1550 °C. The composition of melts and residual minerals constrain the possible melting processes on Mars at 50 to 200 km depth under nominally anhydrous conditions. Silicate melts produced by low degrees of melting (<10 wt.%) were analyzed in layers of vitreous carbon spheres or in micro-cracks inside the graphite capsule. The total range of melt fractions investigated extends from 5 to 50 wt.%, and the liquids produced display variable SiO2 (43.7-59.0 wt.%), MgO (5.3-18.6 wt.%) and Na2O + K2O (1.0-6.5 wt.%) contents. We provide a new equation to estimate the solidus temperature of the martian mantle: T (°C) = 1033 + 168.1 P (GPa) - 14.22P2 (GPa), which places the solidus 50 °C below that of fertile terrestrial peridotites. Low- and high-degree melts are compared to martian alkaline rocks and basalts, respectively. We suggest that the parental melt of Adirondack-class basalts was produced by ∼25 wt.% melting of the primitive martian mantle at 1.5 GPa (∼135 km) and ∼1400 °C. Despite its brecciated nature, NWA 7034/7533 might be composed of material that initially crystallized from a primary melt produced by ∼10-30 wt.% melting at the same pressure. Other igneous rocks from Mars require mantle reservoirs with different CaO/Al2O3 and FeO/MgO ratios or the action of fractional crystallization. Alkaline rocks can be derived from mantle sources with alkali contents (∼0.5 wt.%) similar to the primitive mantle.
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Static compression of the 3.65 Å phase of MgSi(OH)6 to 45 GPa
NASA Astrophysics Data System (ADS)
Speziale, S.; Wunder, B.; Reichmann, H. J.; Marquardt, H.; Jahn, S.; Koch-Mueller, M.; Liermann, H.
2011-12-01
Dense hydrous magnesium silicates (DHMS), due to their high-pressure stability and large hydrogen content, are important potential carriers for deep water recycling in the deep Earth. They can play an especially relevant role in regions related to recent and old subduction. Knowledge of their physical properties is necessary to constrain the chemical budget of hydrogen in the Earth interior. The high-pressure polymorph of stoichimetric MgSi(OH)6 stable at pressures above 9 GPa and temperatures below 500 °C, often referred to as "3.65 Å phase" is one of the members of the DHMS family. Phase 3.65 Å is the only DHMS, together with phase D, with Si only in octahedral coordination. The 3.65 Å phase sample was synthesized at 10 GPa and 425 °C in a multi-anvil apparatus and the structure and chemical composition of were precisely characterized in a very recent study (Wunder et al., 2011). The composition is stoichiometric MgSi(OH)6; its structure is strongly related to that of δ-Al(OH)3, and it can be considered as a modified hydrous A-site defective perovskite. The structural refinement was compatible with Pnma space group suggesting a random distribution of Si and Mg in the A-site. A structure based on P212121 is also compatible with the x-ray diffraction data and would imply partial ordering of H. Additional ab initio computations indicate that a small monoclinic distortion is induced by structural ordering of Mg and Si leading to P21. Here we present the results of a high-pressure x-ray diffraction study on the same synthesis product compressed in the diamond-anvil cell up to 45 GPa at ambient temperature. The powdered sample was loaded in a short symmetric diamond-anvil cell together with few ruby spheres and few specks of Au foil as pressures gauges. Ne was used as a pressure transmitting medium to insure quasi-hydrostatic stress conditions. The x-ray measurements were performed at the new extreme condition beamline (P02.2) of PETRA III synchrotron source at
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ERIC Educational Resources Information Center
Reese, Valerie L.; Dunn, Rita
2008-01-01
This research examined: a) the extent of diversity that exists among entering college freshmen's learning styles; b) whether, and the extent to which, learning style is influenced by gender; and c) whether high school grade point average (HS/GPA) is a determining factor in academic success. The "Productivity Environmental Preference…
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Nisr, C.; Leinenweber, K.; Prakapenka, V.
Although it has previously been considered to be essentially anhydrous, Al-free stishovite can contain up to ~1.3 wt % of H2O, perhaps through the direct substitution ( math formula), according to recent studies. Yet the stability of such substitution and its impact on the properties of silica and rutile-structured hydrous phases (such as δ-AlOOH and phase H) are unknown at the conditions of the deeper mantle. We have synthesized hydrous and anhydrous Al-free stishovite samples at 723 K and 9 GPa, and 1473 K and 10 GPa, respectively. Synchrotron X-ray diffraction patterns show that the unit cell volume of hydrousmore » stishovite is 1.3% greater than that of anhydrous stishovite at 1 bar, suggesting significant incorporation of OH in the crystal structure (3.2 ± 0.5 wt % H2O). At 300 K, we found a lower and broader transition pressure from rutile type to CaCl2 type (28–42 GPa) in hydrous dense silica. We also found that hydrous silica polymorphs are more compressible than their anhydrous counterparts. After the phase transition, the unit cell volume of hydrous silica becomes the same as that of anhydrous silica, showing that the proton incorporation through a direct substitution can be further stabilized at high pressure. The lower pressure transition and the pressure stabilization of the proton incorporation in silica would provide ways to transport and store water in the lower mantle in silica-rich heterogeneities, such as subducted oceanic crust.« less
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Shock compression of Fe-FeS mixture up to 204 GPa
NASA Astrophysics Data System (ADS)
Huang, Haijun; Wu, Shijie; Hu, Xiaojun; Wang, Qingsong; Wang, Xiang; Fei, Yingwei
2013-02-01
AbstractUsing a two-stage light gas gun, we obtained new shock wave Hugoniot data for an iron-sulfur alloy (Fe-11.8wt%S) over the pressure range of 94-204 <span class="hlt">GPa</span>. A least-squares fit to the Hugoniot data yields a linear relationship between shock velocity DS and particle velocity u, DS (km/s) =3.60(0.14) +1.57(0.05) u. The measured Hugoniot data for Fe-11.8wt%S agree well with the calculated results based on the thermodynamic parameters of Fe and FeS using the additive law. By comparing the calculated densities along the adiabatic core temperature with the PREM density profile, an iron core with 10 wt.% sulfur (S) provides the best solution for the composition of the Earth's outer core.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22617045-quasi-isentropic-compressibility-strongly-nonideal-deuterium-plasma-pressures-up-gpa-nonideality-degeneracy-effects','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22617045-quasi-isentropic-compressibility-strongly-nonideal-deuterium-plasma-pressures-up-gpa-nonideality-degeneracy-effects"><span>Quasi-isentropic compressibility of a strongly nonideal deuterium plasma at pressures of up to 5500 <span class="hlt">GPa</span>: Nonideality and degeneracy effects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Mochalov, M. A., E-mail: postmaster@ifv.vniief.ru; Il’kaev, R. I.; Fortov, V. E.</p> <p></p> <p>We report on the experimental results on the quasi-isentropic compressibility of a strongly nonideal deuterium plasma that have been obtained on setups of cylindrical and spherical geometries in the pressure range of up to P ≈ 5500 <span class="hlt">GPa</span>. We describe the characteristics of experimental setups, as well as the methods for the diagnostics and interpretation of the experimental results. The trajectory of metal shells that compress the deuterium plasma was detected using powerful pulsed X-ray sources with a maximal electron energy of up to 60 MeV. The values of the plasma density, which varied from ρ ≈ 0.8 g/cm{sup 3}more » to ρ ≈ 6 g/cm{sup 3}, which corresponds to pressure P ≈ 5500 <span class="hlt">GPa</span> (55 Mbar), were determined from the measured value of the shell radius at the instant that it was stopped. The pressure of the compressed plasma was determined using gasdynamic calculations taking into account the actual characteristics of the experimental setups. We have obtained a strongly compressed deuterium plasma in which electron degeneracy effects under the conditions of strong interparticle interaction are significant. The experimental results have been compared with the theoretical models of a strongly nonideal partly degenerate plasma. We have obtained experimental confirmation of the plasma phase transition in the pressure range near 150 <span class="hlt">GPa</span> (1.5 Mbar), which is in keeping with the conclusion concerning anomaly in the compressibility of the deuterium plasma drawn in [1].« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27103953','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27103953"><span>Predictive value of grade point average (<span class="hlt">GPA</span>), Medical College Admission Test (MCAT), internal examinations (Block) and National Board of Medical Examiners (NBME) scores on Medical Council of Canada qualifying examination part I (MCCQE-1) scores.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roy, Banibrata; Ripstein, Ira; Perry, Kyle; Cohen, Barry</p> <p>2016-01-01</p> <p>To determine whether the pre-medical Grade Point Average (<span class="hlt">GPA</span>), Medical College Admission Test (MCAT), Internal examinations (Block) and National Board of Medical Examiners (NBME) scores are correlated with and predict the Medical Council of Canada Qualifying Examination Part I (MCCQE-1) scores. Data from 392 admitted students in the graduating classes of 2010-2013 at University of Manitoba (UofM), College of Medicine was considered. Pearson's correlation to assess the strength of the relationship, multiple linear regression to estimate MCCQE-1 score and stepwise linear regression to investigate the amount of variance were employed. Complete data from 367 (94%) students were studied. The MCCQE-1 had a moderate-to-large positive correlation with NBME scores and Block scores but a low correlation with <span class="hlt">GPA</span> and MCAT scores. The multiple linear regression model gives a good estimate of the MCCQE-1 (R2 =0.604). Stepwise regression <span class="hlt">analysis</span> demonstrated that 59.2% of the variation in the MCCQE-1 was accounted for by the NBME, but only 1.9% by the Block exams, and negligible variation came from the <span class="hlt">GPA</span> and the MCAT. Amongst all the examinations used at UofM, the NBME is most closely correlated with MCCQE-1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011GeoJI.187.1393Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011GeoJI.187.1393Z"><span>Measurements of wave velocity and electrical conductivity of an amphibolite from southwestern margin of the Tarim Basin at pressures to 1.0 <span class="hlt">GPa</span> and temperatures to 700 °C: comparison with field observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Wenge; Fan, Dawei; Liu, Yonggang; Xie, Hongsen</p> <p>2011-12-01</p> <p>In situ measurements of elastic wave velocities and electrical conductivities in the three structural directions (normal to foliation Z, perpendicular to lineation in foliation Y and parallel to lineation X) for an amphibolite collected from southwestern margin of the Tarim Basin, northwest China, were carried out in the laboratory. The elastic wave velocity was measured with the combined transmission-reflection method at pressures up to 1.0 <span class="hlt">GPa</span> (at room temperature) and temperatures up to 700 °C (at 1.0 <span class="hlt">GPa</span>) and the electrical conductivity was measured with the impedance spectroscopy from 250 to 700 °C at 1.0 <span class="hlt">GPa</span>. The experimentally determined data included compressional (Vp) and shear wave velocities (Vs), velocity anisotropy (Av), intrinsic pressure and temperature derivatives of Vp and Vs, electrical conductivity (σ), electrical conductivity anisotropy (Aσ) and the parameters of the Arrhenius relationship. Elastic wave velocities increase in the structural directions Z, Y, X, with Vp of 6.63, 6.78 and 6.95 km s-1 and Vs of 3.75, 3.82 and 3.96 km s-1 for Z, Y and X, respectively, at pressure of 1.0 <span class="hlt">GPa</span>. Elastic wave velocities increase linearly with pressure at room temperature and pressures between 0.25 and 1.0 <span class="hlt">GPa</span> and decrease linearly with increasing temperature at 1.0 <span class="hlt">GPa</span>. The pressure coefficients of the sample are in the range of 0.1883-0.2308 km s-1 <span class="hlt">GPa</span>-1 for Vp and 0.1149-0.1678 km s-1 <span class="hlt">GPa</span>-1 for Vs. The temperature coefficients are in the range of 2.09-2.35 × 10-4 km s-1 <span class="hlt">GPa</span>-1 for Vp and 1.28-1.68 × 10-4 km s-1 <span class="hlt">GPa</span>-1 for Vs. The electrical conductivity increases with increasing temperature, consistent with the Arrhenius relationship. Activation energies for the three structural directions of the amphibolite are in the range of 0.71-0.75 eV. The amphibolite shows velocity anisotropy (4.15-4.86 per cent for Vp and 5.29-5.84 per cent for Vs at 0.25-1.0 <span class="hlt">GPa</span>) and electrical conductivity anisotropy (11.1-25.2 per cent). Based on the regional crust model</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1332405','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1332405"><span>The mobility of Nb in rutile-saturated NaCl- and NaF-bearing aqueous fluids from 1–6.5 <span class="hlt">GPa</span> and 300–800 °C</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Tanis, Elizabeth A.; Simon, Adam; Tschauner, Oliver</p> <p></p> <p>Rutile (TiO 2) is an important host phase for high field strength elements (HFSE) such as Nb in metamorphic and subduction zone environments. The observed depletion of Nb in arc rocks is often explained by the hypothesis that rutile sequesters HFSE in the subducted slab and overlying sediment, and is chemically inert with respect to aqueous fluids evolved during prograde metamorphism in the forearc to subarc environment. However, field observations of exhumed terranes, and experimental studies, indicate that HFSE may be soluble in complex aqueous fluids at high pressure (i.e., >0.5 <span class="hlt">GPa</span>) and moderate to high temperature (i.e., >300 °C).more » In this study, we investigated experimentally the mobility of Nb in NaCl- and NaF-bearing aqueous fluids in equilibrium with Nb-bearing rutile at pressure-temperature conditions applicable to fluid evolution in arc environments. Niobium concentrations in aqueous fluid at rutile saturation were measured directly by using a hydrothermal diamond-anvil cell (HDAC) and synchrotron X-ray fluorescence (SXRF) at 2.1 to 6.5 <span class="hlt">GPa</span> and 300-500 °C, and indirectly by performing mass loss experiments in a piston-cylinder (PC) apparatus at similar to 1 <span class="hlt">GPa</span> and 700-800 °C. The concentration of Nb in a 10 wt% NaCl aqueous fluid increases from 6 to 11 mu g/g as temperature increases from 300 to 500 °C, over a pressure range from 2.1 to 2.8 <span class="hlt">GPa</span>, consistent with a positive temperature dependence. The concentration of Nb in a 20 wt% NaCl aqueous fluid varies from 55 to 150 mu g/g at 300 to 500 °C, over a pressure range from 1.8 to 6.4 <span class="hlt">GPa</span>; however, there is no discernible temperature or pressure dependence. Here, the Nb concentration in a 4 wt% NaF-bearing aqueous fluid increases from 180 to 910 mu g/g as temperature increases from 300 to 500 °C over the pressure range 2.1 to 6.5 <span class="hlt">GPa</span>. The data for the F-bearing fluid indicate that the Nb content of the fluid exhibits a dependence on temperature between 300 and 500 °C at ≥ 2 <span class="hlt">GPa</span>, but there</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1191747-mobility-nb-rutile-saturated-nacl-naf-bearing-aqueous-fluids-from-gpa','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1191747-mobility-nb-rutile-saturated-nacl-naf-bearing-aqueous-fluids-from-gpa"><span>The mobility of Nb in rutile-saturated NaCl- and NaF-bearing aqueous fluids from 1–6.5 <span class="hlt">GPa</span> and 300–800 °C</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Tanis, Elizabeth A.; Simon, Adam; Tschauner, Oliver</p> <p></p> <p>Rutile (TiO₂) is an important host phase for high field strength elements (HFSE) such as Nb in metamorphic and subduction zone environments. The observed depletion of Nb in arc rocks is often explained by the hypothesis that rutile sequesters HFSE in the subducted slab and overlying sediment, and is chemically inert with respect to aqueous fluids evolved during prograde metamorphism in the forearc to subarc environment. However, field observations of exhumed terranes, and experimental studies, indicate that HFSE may be soluble in complex aqueous fluids at high pressure (i.e., >0.5 <span class="hlt">GPa</span>) and moderate to high temperature (i.e., >300 °C). Inmore » this study, we investigated experimentally the mobility of Nb in NaCl- and NaF-bearing aqueous fluids in equilibrium with Nb-bearing rutile at pressure-temperature conditions applicable to fluid evolution in arc environments. Niobium concentrations in aqueous fluid at rutile saturation were measured directly by using a hydrothermal diamond-anvil cell (HDAC) and synchrotron X-ray fluorescence (SXRF) at 2.1 to 6.5 <span class="hlt">GPa</span> and 300–500 °C, and indirectly by performing mass loss experiments in a piston-cylinder (PC) apparatus at ~1 <span class="hlt">GPa</span> and 700–800 °C. The concentration of Nb in a 10 wt% NaCl aqueous fluid increases from 6 to 11 μg/g as temperature increases from 300 to 500 °C, over a pressure range from 2.1 to 2.8 <span class="hlt">GPa</span>, consistent with a positive temperature dependence. The concentration of Nb in a 20 wt% NaCl aqueous fluid varies from 55 to 150 μg/g at 300 to 500 °C, over a pressure range from 1.8 to 6.4 <span class="hlt">GPa</span>; however, there is no discernible temperature or pressure dependence. The Nb concentration in a 4 wt% NaF-bearing aqueous fluid increases from 180 to 910 μg/g as temperature increases from 300 to 500 °C over the pressure range 2.1 to 6.5 <span class="hlt">GPa</span>. The data for the F-bearing fluid indicate that the Nb content of the fluid exhibits a dependence on temperature between 300 and 500 °C at ≥2 <span class="hlt">GPa</span>, but there is no observed</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1332405-mobility-nb-rutile-saturated-nacl-naf-bearing-aqueous-fluids-from-gpa','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1332405-mobility-nb-rutile-saturated-nacl-naf-bearing-aqueous-fluids-from-gpa"><span>The mobility of Nb in rutile-saturated NaCl- and NaF-bearing aqueous fluids from 1–6.5 <span class="hlt">GPa</span> and 300–800 °C</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Tanis, Elizabeth A.; Simon, Adam; Tschauner, Oliver; ...</p> <p>2015-07-01</p> <p>Rutile (TiO 2) is an important host phase for high field strength elements (HFSE) such as Nb in metamorphic and subduction zone environments. The observed depletion of Nb in arc rocks is often explained by the hypothesis that rutile sequesters HFSE in the subducted slab and overlying sediment, and is chemically inert with respect to aqueous fluids evolved during prograde metamorphism in the forearc to subarc environment. However, field observations of exhumed terranes, and experimental studies, indicate that HFSE may be soluble in complex aqueous fluids at high pressure (i.e., >0.5 <span class="hlt">GPa</span>) and moderate to high temperature (i.e., >300 °C).more » In this study, we investigated experimentally the mobility of Nb in NaCl- and NaF-bearing aqueous fluids in equilibrium with Nb-bearing rutile at pressure-temperature conditions applicable to fluid evolution in arc environments. Niobium concentrations in aqueous fluid at rutile saturation were measured directly by using a hydrothermal diamond-anvil cell (HDAC) and synchrotron X-ray fluorescence (SXRF) at 2.1 to 6.5 <span class="hlt">GPa</span> and 300-500 °C, and indirectly by performing mass loss experiments in a piston-cylinder (PC) apparatus at similar to 1 <span class="hlt">GPa</span> and 700-800 °C. The concentration of Nb in a 10 wt% NaCl aqueous fluid increases from 6 to 11 mu g/g as temperature increases from 300 to 500 °C, over a pressure range from 2.1 to 2.8 <span class="hlt">GPa</span>, consistent with a positive temperature dependence. The concentration of Nb in a 20 wt% NaCl aqueous fluid varies from 55 to 150 mu g/g at 300 to 500 °C, over a pressure range from 1.8 to 6.4 <span class="hlt">GPa</span>; however, there is no discernible temperature or pressure dependence. Here, the Nb concentration in a 4 wt% NaF-bearing aqueous fluid increases from 180 to 910 mu g/g as temperature increases from 300 to 500 °C over the pressure range 2.1 to 6.5 <span class="hlt">GPa</span>. The data for the F-bearing fluid indicate that the Nb content of the fluid exhibits a dependence on temperature between 300 and 500 °C at ≥ 2 <span class="hlt">GPa</span>, but there</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1286804-structure-co2-hydrate-between-gpa','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1286804-structure-co2-hydrate-between-gpa"><span>The structure of CO 2 hydrate between 0.7 and 1.0 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Tulk, Chris A.; Machida, Shinichi; Klug, Dennis D.; ...</p> <p>2014-11-05</p> <p>A deuterated sample of CO 2 structure I (sI) clathrate hydrate (CO 2 ∙ 8.3 D 2O) has been formed and neutron diffraction experiments up to 1.0 <span class="hlt">GPa</span> at 240 K were performed. The sI CO 2 hydrate transformed at 0.7 <span class="hlt">GPa</span> into the high pressure phase that had been observed previously by Hirai, et al. (J. Phys. Chem. 133, 124511 (2010)) and O. Bollengier et al. (Geochim. Cosmochim. AC. 119, 322 (2013)), but which had not been structurally identified. The current neutron diffraction data were successfully fitted to a filled ice structure with CO 2 molecules filling the watermore » channels. This CO 2+water system has also been investigated using classical molecular dynamics and density functional ab initio methods to provide additional characterization of the high pressure structure. Both models indicate the water network adapts an MH-III ‘like’ filled ice structure with considerable disorder of the orientations of the CO 2molecule. Furthermore, the disorder appears be a direct result of the level of proton disorder in the water network. In contrast to the conclusions of Bollengier et al. our neutron diffraction data shows that the filled ice phase can be recovered to ambient pressure (0.1 MPa) at 96 K, and recrystallization to sI hydrate occurs upon subsequent heating to 150 K, possibly by first forming low density amorphous ice. Unlike other clathrate hydrate systems, which transform from the sI or sII structure to the hexagonal structure (sH) then to the filled ice structure, CO 2 hydrate transforms directly from the sI form to the filled ice structure.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1387495-structure-co-hydrate-between-gpa','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1387495-structure-co-hydrate-between-gpa"><span>The structure of CO 2 hydrate between 0.7 and 1.0 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Tulk, C. A.; Machida, S.; Klug, D. D.</p> <p></p> <p>A deuterated sample of CO2 structure I (sI) clathrate hydrate (CO2·8.3 D2O) has been formed and neutron diffraction experiments up to 1.0 <span class="hlt">GPa</span> at 240 K were performed. The sI CO2 hydrate transformed at 0.7 <span class="hlt">GPa</span> into the high pressure phase that had been observed previously by Hirai et al. [J. Phys. Chem. 133, 124511 (2010)] and Bollengier et al. [Geochim. Cosmochim. Acta 119, 322 (2013)], but which had not been structurally identified. The current neutron diffraction data were successfully fitted to a filled ice structure with CO2 molecules filling the water channels. This CO2+water system has also been investigatedmore » using classical molecular dynamics and density functional ab initio methods to provide additional characterization of the high pressure structure. Both models indicate the water network adapts a MH-III “like” filled ice structure with considerable disorder of the orientations of the CO2 molecule. Furthermore, the disorder appears to be a direct result of the level of proton disorder in the water network. In contrast to the conclusions of Bollengier et al., our neutron diffraction data show that the filled ice phase can be recovered to ambient pressure (0.1 MPa) at 96 K, and recrystallization to sI hydrate occurs upon subsequent heating to 150 K, possibly by first forming low density amorphous ice. Unlike other clathrate hydrate systems, which transform from the sI or sII structure to the hexagonal structure (sH) then to the filled ice structure, CO2 hydrate transforms directly from the sI form to the filled ice structure.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1286804','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1286804"><span>The structure of CO 2 hydrate between 0.7 and 1.0 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Tulk, Chris A.; Machida, Shinichi; Klug, Dennis D.</p> <p></p> <p>A deuterated sample of CO 2 structure I (sI) clathrate hydrate (CO 2 ∙ 8.3 D 2O) has been formed and neutron diffraction experiments up to 1.0 <span class="hlt">GPa</span> at 240 K were performed. The sI CO 2 hydrate transformed at 0.7 <span class="hlt">GPa</span> into the high pressure phase that had been observed previously by Hirai, et al. (J. Phys. Chem. 133, 124511 (2010)) and O. Bollengier et al. (Geochim. Cosmochim. AC. 119, 322 (2013)), but which had not been structurally identified. The current neutron diffraction data were successfully fitted to a filled ice structure with CO 2 molecules filling the watermore » channels. This CO 2+water system has also been investigated using classical molecular dynamics and density functional ab initio methods to provide additional characterization of the high pressure structure. Both models indicate the water network adapts an MH-III ‘like’ filled ice structure with considerable disorder of the orientations of the CO 2molecule. Furthermore, the disorder appears be a direct result of the level of proton disorder in the water network. In contrast to the conclusions of Bollengier et al. our neutron diffraction data shows that the filled ice phase can be recovered to ambient pressure (0.1 MPa) at 96 K, and recrystallization to sI hydrate occurs upon subsequent heating to 150 K, possibly by first forming low density amorphous ice. Unlike other clathrate hydrate systems, which transform from the sI or sII structure to the hexagonal structure (sH) then to the filled ice structure, CO 2 hydrate transforms directly from the sI form to the filled ice structure.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/979205-transport-properties-undoped-br-doped-pbte-sintered-high-temperature-pressure-gpa','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/979205-transport-properties-undoped-br-doped-pbte-sintered-high-temperature-pressure-gpa"><span>Transport properties of undoped and Br-doped PbTe sintered at high temperature and pressure> 4.0 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Yongkwan, Dong; McGuire, Michael A; Malik, Abds-Sami</p> <p>2009-01-01</p> <p>The thermoelectric properties of nominally undoped PbTe and Br doped PbTe materials sintered at high-pressure and high-temperature (HPHT) have been studied. All samples show n-type semiconducting behavior with negative thermopower. For undoped PbTe, four different HPHT treatments were performed at pressures between 4.0 and 6.5 <span class="hlt">GPa</span>. PbTe doped with Br at 0.5, 1.0, 2.0, 3.0 x 10{sup 19} cm{sup -3} was HPHT treated at 4.0 <span class="hlt">GPa</span> and 1045 C. As the dopant concentration increases, the absolute thermopower decreases, thermal conductivity increases, and electrical resistivity decreases. At a nominal dopant concentration of 1.0 x 10{sup 19} cm{sup -3}, carrier mobility ofmore » 1165 cm{sup 2}/V s and dimensionless thermoelectric figure-of-merit, ZT, of around 0.27 at 300 K were obtained. These results demonstrate that HPHT post-processing is a viable and controllable way of tuning the thermoelectric properties of PbTe-based materials.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CoMP..170...18B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CoMP..170...18B"><span>Reduced sediment melting at 7.5-12 <span class="hlt">GPa</span>: phase relations, geochemical signals and diamond nucleation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brey, G. P.; Girnis, A. V.; Bulatov, V. K.; Höfer, H. E.; Gerdes, A.; Woodland, A. B.</p> <p>2015-08-01</p> <p>Melting of carbonated sediment in the presence of graphite or diamond was experimentally investigated at 7.5-12 <span class="hlt">GPa</span> and 800-1600 °C in a multianvil apparatus. Two starting materials similar to GLOSS of Plank and Langmuir (Chem Geol 145:325-394, 1998) were prepared from oxides, carbonates, hydroxides and graphite. One mixture (Na-gloss) was identical in major element composition to GLOSS, and the other was poorer in Na and richer in K (K-gloss). Both starting mixtures contained ~6 wt% CO2 and 7 wt% H2O and were doped at a ~100 ppm level with a number of trace elements, including REE, LILE and HFSE. The near-solidus mineral assemblage contained a silica polymorph (coesite or stishovite), garnet, kyanite, clinopyroxene, carbonates (aragonite and magnesite-siderite solid solution), zircon, rutile, bearthite and hydrous phases (phengite and lawsonite at <9 <span class="hlt">GPa</span> and the hydrous aluminosilicates topaz-OH and phase egg at >10 <span class="hlt">GPa</span>). Hydrous phases disappear at ~900 °C, and carbonates persist up to 1000-1100 °C. At temperatures >1200 °C, the mineral assemblage consists of coesite or stishovite, kyanite and garnet. Clinopyroxene stability depends strongly on the Na content in the starting mixture; it remains in the Na-gloss composition up to 1600 °C at 12 <span class="hlt">GPa</span>, but was not observed in K-gloss experiments above 1200 °C. The composition of melt or fluid changes gradually with increasing temperature from hydrous carbonate-rich (<10 wt% SiO2) at 800-1000 °C to volatile-rich silicate liquids (up to 40 wt% SiO2) at high temperatures. Trace elements were analyzed in melts and crystalline phases by LA ICP MS. The garnet-melt and clinopyroxene-melt partition coefficients are in general consistent with results from the literature for volatile-free systems and silicocarbonate melts derived by melting carbonated peridotites. Most trace elements are strongly incompatible in kyanite and silica polymorphs ( D < 0.01), except for V, Cr and Ni, which are slightly compatible in kyanite</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=maxima&pg=3&id=EJ673997','ERIC'); return false;" href="https://eric.ed.gov/?q=maxima&pg=3&id=EJ673997"><span>Global Optimality of the Successive Maxbet Algorithm.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hanafi, Mohamed; ten Berge, Jos M. F.</p> <p>2003-01-01</p> <p>It is known that the Maxbet algorithm, which is an alternative to the method of generalized canonical correlation <span class="hlt">analysis</span> and <span class="hlt">Procrustes</span> <span class="hlt">analysis</span>, may converge to local maxima. Discusses an eigenvalue criterion that is sufficient, but not necessary, for global optimality of the successive Maxbet algorithm. (SLD)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1251076-high-pressure-structure-equation-state-diamino-dinitropyrazine-oxide-llm-up-gpa-ray-diffraction-measurements-first-principles-molecular-dynamics-simulations','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1251076-high-pressure-structure-equation-state-diamino-dinitropyrazine-oxide-llm-up-gpa-ray-diffraction-measurements-first-principles-molecular-dynamics-simulations"><span>The high pressure structure and equation of state of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) up to 20 <span class="hlt">GPa</span>: X-ray diffraction measurements and first principles molecular dynamics simulations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Stavou, Elissaios; Manaa, M. Riad; Zaug, Joseph M.; ...</p> <p>2015-10-14</p> <p>Recent theoretical studies of 2,6-diamino-3,5-dinitropyrazine-1-oxide (C 4H 4N 6O 5 Lawrence Livermore Molecule No. 105, LLM-105) report unreacted high pressure equations of state that include several structural phase transitions, between 8 and 50 <span class="hlt">GPa</span>, while one published experimental study reports equation of state (EOS) data up to a pressure of 6 <span class="hlt">GPa</span> with no observed transition. Here we report the results of a synchrotron-based X-ray diffraction study and also ambient temperature isobaric-isothermal atomistic molecular dynamics simulations of LLM-105 up to 20 <span class="hlt">GPa</span>. We find that the ambient pressure phase remains stable up to 20 <span class="hlt">GPa</span>; there is no indication ofmore » a pressure induced phase transition. We do find a prominent decrease in b-axis compressibility starting at approximately 13 <span class="hlt">GPa</span> and attribute the stiffening to a critical length where inter-sheet distance becomes similar to the intermolecular distance within individual sheets. The ambient temperature isothermal equation of state was determined through refinements of measured X-ray diffraction patterns. The pressure-volume data were fit using various EOS models to yield bulk moduli with corresponding pressure derivatives. As a result, we find very good agreement between the experimental and theoretically derived EOS.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..SHK.B4001H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..SHK.B4001H"><span>Survival of Shewanella Oneidensis MR-1 to <span class="hlt">GPa</span> pressures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hazael, Rachael; Foglia, Fabrizia; Leighs, James; Appleby-Thomas, Gareth; Daniel, Isabelle; Eakins, Daniel; Meersman, Filip; McMillian, Paul</p> <p>2013-06-01</p> <p>Most life on Earth is thought to occupy near-surface environments under relatively mild conditions of temperature, pressure, pH, salinity etc. That view is changing following discovery of extremophile organisms that prefer environments based on high or low T, extreme chemistries, or very high pressures. Over the past three decades, geomicrobiologists have discovered an extensive subsurface biosphere, that may account for between 1/10 to 1/3 of Earth's living biomass. We subjected samples of Shewanella oneidensis to several pressure cycles to examine its survival to static high pressures to above 1.5 <span class="hlt">GPa</span>. Shewanella forms part of a genus that contains several piezophile species like S. violacea and S. benthica. We have obtained growth curves for populations recovered from high P conditions and cultured in the laboratory, before being subjected to even higher pressures. We have also carried out dynamic shock experiments using a specially designed cell to maintain high-P, low-T conditions during shock-recovery experiments and observe colony formation among the survivors. Colony counts, shape and growth curves allow us to compare the static vs dynamic pressure resistance of wild type vs pressure-adapted strains. Leverhulme</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=alcohol&pg=3&id=EJ1077890','ERIC'); return false;" href="https://eric.ed.gov/?q=alcohol&pg=3&id=EJ1077890"><span>The Indirect Effect of Alcohol Use on <span class="hlt">GPA</span> in First-Semester College Students: The Mediating Role of Academic Effort</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Conway, James M.; DiPlacido, Joanne</p> <p>2015-01-01</p> <p>This study focused on first-semester college students, investigating (a) indirect effects of aggregate alcohol use on grade point average (<span class="hlt">GPA</span>) through academic effort (skipping class and time on schoolwork) and (b) daily effects of alcohol use on reduced effort. Eighty students reported daily alcohol use and academic effort (skipping class and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27490899','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27490899"><span>Sex determination by three-dimensional geometric morphometrics of craniofacial form.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chovalopoulou, Maria-Eleni; Valakos, Efstratios D; Manolis, Sotiris K</p> <p></p> <p>The purpose of the present study is to define which regions of the cranium, the upper-face, the orbits and the nasal are the most sexually dimorphic, by using three-dimensional geometric morphometric methods, and investigate the effectiveness of this method in determining sex from the shape of these regions. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived in Greece during the 20(th) century. The three-dimensional co-ordinates of 31 ecto-cranial landmarks were digitized using a MicroScribe 3DX contact digitizer. Goodall's F-test was performed in order to compare statistical differences in shape between males and females. Generalized <span class="hlt">Procrustes</span> <span class="hlt">Analysis</span> (<span class="hlt">GPA</span>) was used to obtain size and shape variables for statistical <span class="hlt">analysis</span>. Shape, Size and Form analyses were carried out by logistic regression and discriminant function <span class="hlt">analysis</span>. The results indicate that there are shape differences between the sexes in the upper-face and the orbits. The highest shape classification rate was obtained from the upper-face region. The centroid size of the caraniofacial and the orbital regions was smaller in females than males. Moreover, it was found that size is significant for sexual dimorphism in the upper-face region. As anticipated, the classification accuracy improves when both size and shape are combined. The findings presented here constitute a firm basis upon which further research can be conducted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1340734-compression-behavior-blodite-low-high-temperature-up-implications-stability-hydrous-sulfates-icy-planetary-bodies','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1340734-compression-behavior-blodite-low-high-temperature-up-implications-stability-hydrous-sulfates-icy-planetary-bodies"><span>The compression behavior of blödite at low and high temperature up to ~10<span class="hlt">GPa</span>: Implications for the stability of hydrous sulfates on icy planetary bodies</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Comodi, Paola; Stagno, Vincenzo; Zucchini, Azzurra</p> <p></p> <p>Recent satellite inferences of hydrous sulfates as recurrent minerals on the surface of icy planetary bodies link with the potential mineral composition of their interior. Blödite, a mixed Mg-Na sulfate, is here taken as representative mineral of icy satellites surface to investigate its crystal structure and stability at conditions of the interior of icy bodies. To this aim we performed in situ synchrotron angle-dispersive X-ray powder diffraction experiments on natural blödite at pressures up to ~10.4 <span class="hlt">GPa</span> and temperatures from ~118.8 K to ~490.0 K using diamond anvil cell technique to investigate the compression behavior and establish a low-to-high temperaturemore » equation of state that can be used as reference when modeling the interior of sulfate-rich icy satellites such as Ganymede. The experimentally determined volume expansivity, α, varies from 7.6 (7) 10 -5 K -1 at 0.0001 <span class="hlt">GPa</span> (from 118.8 to 413.15 K) to 2.6 (3) 10 -5 K -1 at 10 <span class="hlt">GPa</span> (from 313.0 to 453.0 K) with a δα/δ P coefficient = -5.6(9)10 -6 <span class="hlt">GPa</span> -1 K -1. The bulk modulus calculated from the least squares fitting of P-V data on the isotherm at 413 K using a second-order Birch - Murnaghan equation of state is 38(5) <span class="hlt">GPa</span>, which gives the value of δK/δ T equal to 0.01(5) <span class="hlt">GPa</span> K -1. The thermo-baric behavior of blödite appears strongly anisotropic with c lattice parameter being more deformed with respect to a and b. Thermogravimetric analyses performed at ambient pressure showed three endotherms at 413 K, 533 K and 973 K with weight losses of approximately 11%, 11% and 43% caused by partial dehydration, full dehydration and sulfate decomposition respectively. Interestingly, no clear evidence of dehydration was observed up to ~453 K and ~10.4 <span class="hlt">GPa</span>, suggesting that pressure acts to stabilize the crystalline structure of blödite. The data collected allow to write the following equation of state, V(P, T) = V 0[1 + 7.6(7)10 - 5ΔT - 0.026(3)P - 5.6(9)10 - 6PΔT-6.6(9)10 - 6PΔT)] from which the density</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PCM....40..195D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PCM....40..195D"><span>Sound velocities of Na0.4Mg0.6Al1.6Si0.4O4 NAL and CF phases to 73 <span class="hlt">GPa</span> determined by Brillouin scattering method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dai, Lidong; Kudo, Yuki; Hirose, Kei; Murakami, Motohiko; Asahara, Yuki; Ozawa, Haruka; Ohishi, Yasuo; Hirao, Naohisa</p> <p>2013-03-01</p> <p>The sound velocities of two aluminum-rich phases in the lower mantle, hexagonal new Al-rich phase (NAL) and its corresponding high-pressure polymorph orthorhombic Ca-ferrite-type phase (CF), were determined with the Brillouin scattering method in a pressure range from 9 to 73 <span class="hlt">GPa</span> at room temperature. Both NAL and CF samples have identical chemical composition of Na0.4Mg0.6Al1.6Si0.4O4 (40 % NaAlSiO4-60 % MgAl2O4). Infrared laser annealing in the diamond anvil cell was performed to minimize the stress state of the sample and obtain the high-quality Brillouin spectra. The results show shear modulus at zero pressure G 0 = 121.960 ± 0.087 <span class="hlt">GPa</span> and its pressure derivative G' = 1.961 ± 0.009 for the NAL phase, and G 0 = 129.653 ± 0.059 <span class="hlt">GPa</span> and G' = 2.340 ± 0.004 for the CF phase. The zero-pressure shear velocities of the NAL and CF phases are obtained to be 5.601 ± 0.005 km/sec and 5.741 ± 0.001 km/sec, respectively. We also found that shear velocity increases by 2.5 % upon phase transition from NAL to CF at around 40 <span class="hlt">GPa</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DokES.474..695G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DokES.474..695G"><span>Experimental study of eclogitization and melting of basic rocks at P = 4 <span class="hlt">GPa</span> and T = 1200-1400°C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gorbachev, N. S.; Shapovalov, Yu. B.; Kostyuk, A. V.</p> <p>2017-06-01</p> <p>Experimental study of gabbro-norite eclogitization and melting at P = 4 <span class="hlt">GPa</span> has made it possible to reveal the effective influence of fluid and temperature on the phase relationships. The melt composition varies from andesite-dacite in "dry conditions" to phonolite and carbonate in the presence of a fluid. The Grt-containing melting curve is replaced by the Cpx-containing liquidus as the temperature changes or a fluid is added. Hence, the possible presence of "garnetitite" and "clinopyroxenite" in the upper mantle was proved experimentally. The ultimate pressure of the spinel facies at the depth of the eclogite upper mantle is controlled by the stability of Cht ≤ 4 <span class="hlt">GPa</span>. The revealed similarity of the spectra of REE-adakite, tonalite-trondhjemite-granodiorite (TTG), and melts formed under the partial melting of eclogitized gabbro-norite does not contradict the existing ideas of the eclogite source of the TTG rocks. Wide variations in the interphase microelement distribution factors D (Grt, Cpx)/L are indicative of effective fractionation of the microelements in the course of eclogite melting and differentiation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SuScT..28l5010M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SuScT..28l5010M"><span>Electronic transport properties of MFe2As2 (M = Ca, Eu, Sr) at ambient and high pressures up to 20 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morozova, Natalia V.; Karkin, Alexander E.; Ovsyannikov, Sergey V.; Umerova, Yuliya A.; Shchennikov, Vladimir V.; Mittal, R.; Thamizhavel, A.</p> <p>2015-12-01</p> <p>We experimentally investigated the electronic transport properties of four iron pnictide crystals, namely, EuFe2As2, SrFe2As2, and CaFe2As2 parent compounds, and superconducting CaFe1.94Co0.06As2 at ambient and high pressures up to 20 <span class="hlt">GPa</span>. At ambient pressure we examined the electrical resistivity, Hall and magnetoresistance effects of the samples in a temperature range from 1.5 to 380 K in high magnetic fields up to 13.6 T. In this work we carried out the first simultaneous investigations of the in-plane and out-of-plane Hall coefficients, and found new peculiarities of the low-temperature magnetic and structural transitions that occur in these materials. In addition, the Hall coefficient data suggested that the parent compounds are semimetals with a multi-band conductivity that includes hole-type and electron-type bands. We measured the pressure dependence of the thermoelectric power (the Seebeck effect) of these samples up to 20 <span class="hlt">GPa</span>, i.e. across the known phase transition from the tetragonal to the collapsed tetragonal lattice. The high-pressure behavior of the thermopower of EuFe2As2 and CaFe2As2 showing the p-n sign inversions was consistent with the semimetal model described above. By means of thermopower, we found in single-crystalline CaFe2As2 direct evidence of the band structure crossover related to the formation of As-As bonds along the c-axis on the tetragonal → collapsed tetragonal phase transition near 2 <span class="hlt">GPa</span>. We showed that this feature is distinctly observable only in high-quality samples, and already for re-pressurization cycles this crossover was strongly smeared because of the moderate deterioration of the sample. We also demonstrated by means of thermopower that the band structure crossover that should accompany the tetragonal → collapsed tetragonal phase transition in EuFe2As2 near 8 <span class="hlt">GPa</span> is hardly visible even in high-quality single crystals. This behavior may be related to a gradual valence change of the Eu ions under pressure that leads to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPRS..119..485M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPRS..119..485M"><span>Shadow detection and removal in RGB VHR images for land use unsupervised classification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Movia, A.; Beinat, A.; Crosilla, F.</p> <p>2016-09-01</p> <p>Nowadays, high resolution aerial images are widely available thanks to the diffusion of advanced technologies such as UAVs (Unmanned Aerial Vehicles) and new satellite missions. Although these developments offer new opportunities for accurate land use <span class="hlt">analysis</span> and change detection, cloud and terrain shadows actually limit benefits and possibilities of modern sensors. Focusing on the problem of shadow detection and removal in VHR color images, the paper proposes new solutions and analyses how they can enhance common unsupervised classification procedures for identifying land use classes related to the CO2 absorption. To this aim, an improved fully automatic procedure has been developed for detecting image shadows using exclusively RGB color information, and avoiding user interaction. Results show a significant accuracy enhancement with respect to similar methods using RGB based indexes. Furthermore, novel solutions derived from <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> have been applied to remove shadows and restore brightness in the images. In particular, two methods implementing the so called "anisotropic <span class="hlt">Procrustes</span>" and the "not-centered oblique <span class="hlt">Procrustes</span>" algorithms have been developed and compared with the linear correlation correction method based on the Cholesky decomposition. To assess how shadow removal can enhance unsupervised classifications, results obtained with classical methods such as k-means, maximum likelihood, and self-organizing maps, have been compared to each other and with a supervised clustering procedure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1355026-single-crystal-ray-diffraction-study-fe2sio4-fayalite-up','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1355026-single-crystal-ray-diffraction-study-fe2sio4-fayalite-up"><span>Single-crystal X-ray diffraction study of Fe 2SiO 4 fayalite up to 31 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Zhang, Jin S.; Hu, Yi; Shelton, Hannah</p> <p>2016-10-03</p> <p>Olivine is widely believed to be the most abundant mineral in the Earth’s upper mantle. Here, we report structural refinement results for the Fe-end-member olivine, Fe 2SiO 4 fayalite, up to 31 <span class="hlt">GPa</span> in diamond-anvil cell, using single-crystal synchrotron X-ray diffraction. Unit-cell parameters a, b, c and V, average Si–O Fe–O bond lengths, as well as Si–O Fe–O polyhedral volumes continuously decrease with increasing pressure. The pressure derivative of isothermal bulk modulus K' T0 is determined to be 4.0 (2) using third-order Birch–Murnaghan equation of state with ambient isothermal bulk modulus fixed to 135 <span class="hlt">GPa</span> on the basis of previousmore » Brillouin measurements. The Si–O tetrahedron is stiffer than the Fe–O octahedra, and the compression mechanism is dominated by Fe–O bond and Fe–O octahedral compression. Densities of olivine along 1600 and 900 K adiabats are calculated based on this study. The existence of metastable olivine inside the cold subduction slab could cause large positive buoyancy force against subduction, slow down the subduction and possibly affect the slab geometry.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22442254','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22442254"><span>Academic procrastination, emotional intelligence, academic self-efficacy, and <span class="hlt">GPA</span>: a comparison between students with and without learning disabilities.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hen, Meirav; Goroshit, Marina</p> <p>2014-01-01</p> <p>Academic procrastination has been seen as an impediment to students' academic success. Research findings suggest that it is related to lower levels of self-regulated learning and academic self-efficacy and associated with higher levels of anxiety, stress, and illness. Emotional intelligence (EI) is the ability to assess, regulate, and utilize emotions and has been found to be associated with academic self-efficacy and a variety of better outcomes, including academic performance. Students with learning disabilities (LD) are well acquainted with academic difficulty and maladaptive academic behavior. In comparison to students without LD, they exhibit high levels of learned helplessness, including diminished persistence, lower academic expectations, and negative affect. This study examined the relationships among academic procrastination, EI, and academic performance as mediated by academic self-efficacy in 287 LD and non-LD students. Results indicated that the indirect effect of EI on academic procrastination and <span class="hlt">GPA</span> was stronger in LD students than in non-LD students. In addition, results indicated that LD students scored lower than non-LD students on both EI and academic self-efficacy and higher on academic procrastination. No difference was found in <span class="hlt">GPA</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Icar..285..137C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Icar..285..137C"><span>The compression behavior of blödite at low and high temperature up to ∼10 <span class="hlt">GPa</span>: Implications for the stability of hydrous sulfates on icy planetary bodies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Comodi, Paola; Stagno, Vincenzo; Zucchini, Azzurra; Fei, Yingwei; Prakapenka, Vitali</p> <p>2017-03-01</p> <p>Recent satellite inferences of hydrous sulfates as recurrent minerals on the surface of icy planetary bodies link with the potential mineral composition of their interior. Blödite, a mixed Mg-Na sulfate, is here taken as representative mineral of icy satellites surface to investigate its crystal structure and stability at conditions of the interior of icy bodies. To this aim we performed in situ synchrotron angle-dispersive X-ray powder diffraction experiments on natural blödite at pressures up to ∼10.4 <span class="hlt">GPa</span> and temperatures from ∼118.8 K to ∼490.0 K using diamond anvil cell technique to investigate the compression behavior and establish a low-to-high temperature equation of state that can be used as reference when modeling the interior of sulfate-rich icy satellites such as Ganymede. The experimentally determined volume expansivity, α, varies from 7.6 (7) 10-5 K-1 at 0.0001 <span class="hlt">GPa</span> (from 118.8 to 413.15 K) to 2.6 (3) 10-5 K-1 at 10 <span class="hlt">GPa</span> (from 313.0 to 453.0 K) with a δα/δP coefficient = -5.6(9)10-6 <span class="hlt">GPa</span>-1 K-1. The bulk modulus calculated from the least squares fitting of P-V data on the isotherm at 413 K using a second-order Birch - Murnaghan equation of state is 38(5) <span class="hlt">GPa</span>, which gives the value of δK/δT equal to 0.01(5) <span class="hlt">GPa</span> K-1. The thermo-baric behavior of blödite appears strongly anisotropic with c lattice parameter being more deformed with respect to a and b. Thermogravimetric analyses performed at ambient pressure showed three endotherms at 413 K, 533 K and 973 K with weight losses of approximately 11%, 11% and 43% caused by partial dehydration, full dehydration and sulfate decomposition respectively. Interestingly, no clear evidence of dehydration was observed up to ∼453 K and ∼10.4 <span class="hlt">GPa</span>, suggesting that pressure acts to stabilize the crystalline structure of blödite. The data collected allow to write the following equation of state, V(P, T) = V0[1 + 7.6(7)10- 5ΔT - 0.026(3)P - 5.6(9)10- 6PΔT-6.6(9)10- 6PΔT)] from which the density of bl</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1226083-validating-density-functional-theory-simulations-high-energy-density-conditions-liquid-krypton-shock-experiments-gpa-sandia-machine','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1226083-validating-density-functional-theory-simulations-high-energy-density-conditions-liquid-krypton-shock-experiments-gpa-sandia-machine"><span>Validating density-functional theory simulations at high energy-density conditions with liquid krypton shock experiments to 850 <span class="hlt">GPa</span> on Sandia's Z machine</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Mattsson, Thomas R.; Root, Seth; Mattsson, Ann E.; ...</p> <p>2014-11-11</p> <p>We use Sandia's Z machine and magnetically accelerated flyer plates to shock compress liquid krypton to 850 <span class="hlt">GPa</span> and compare with results from density-functional theory (DFT) based simulations using the AM05 functional. We also employ quantum Monte Carlo calculations to motivate the choice of AM05. We conclude that the DFT results are sensitive to the quality of the pseudopotential in terms of scattering properties at high energy/temperature. A new Kr projector augmented wave potential was constructed with improved scattering properties which resulted in excellent agreement with the experimental results to 850 <span class="hlt">GPa</span> and temperatures above 10 eV (110 kK). Inmore » conclusion, we present comparisons of our data from the Z experiments and DFT calculations to current equation of state models of krypton to determine the best model for high energy-density applications.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1083352-high-pressure-phase-transitions-fe3-xtixo4-solid-solution-up-gpa-correlated-electronic-spin-transition','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1083352-high-pressure-phase-transitions-fe3-xtixo4-solid-solution-up-gpa-correlated-electronic-spin-transition"><span>High-pressure phase transitions of Fe 3-xTi xO 4 solid solution up to 60 <span class="hlt">GPa</span> correlated with electronic spin transition</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Yamanaka, Takamitsu; Kyono, Atsushi; Nakamoto, Yuki</p> <p>2013-06-12</p> <p>The structural phase transition of the titanomagnetite (Fe 3–xTi xO 4) solid solution under pressures up to 60 <span class="hlt">GPa</span> has been clarified by single-crystal and powder diffraction studies using synchrotron radiation and a diamond-anvil cell. Present Rietveld structure refinements of the solid solution prove that the prefered cation distribution is based on the crystal field preference rather than the magnetic spin ordering in the solid solution. The Ti-rich phases in 0.734 ≤ x ≤1.0 undergo a phase transformation from the cubic spinel of Fd3m to the tetragonal spinel structure of I4 1/amd with c/a < 1.0. The transition is drivenmore » by a Jahn-Teller effect of IVFe 2+ (3d 6) on the tetrahedral site. The c/a < 1 ratio is induced by lifting of the degeneracy of the e orbitals by raising the d x2-y2 orbital below the energy of the d z2 orbital. The distortion characterized by c/a < 1 is more pronounced with increasing Ti content in the Fe 3–xTi xO 4 solid solutions and with increasing pressure. An X-ray emission experiment of Fe 2TiO 4 at high pressures confirms the spin transition of FeKβ from high spin to intermediate spin (IS) state. The high spin (HS)-to-low spin (LS) transition starts at 14 <span class="hlt">GPa</span> and the IS state gradually increases with compression. The VIFe 2+ in the octahedral site is more prone for the HS-to-LS transition, compared with Fe 2+ in the fourfold- or eightfold-coordinated site. The transition to the orthorhombic post-spinel structure with space group Cmcm has been confirmed in the whole compositional range of Fe 3–xTi xO 4. The transition pressure decreases from 25 <span class="hlt">GPa</span> (x = 0.0) to 15 <span class="hlt">GPa</span> (x = 1.0) with increasing Ti content. There are two cation sites in the orthorhombic phase: M1 and M2 sites of eightfold and sixfold coordination, respectively. Fe 2+ and Ti 4+ are disordered on the M2 site. This structural change is accelerated at higher pressures due to the spin transition of Fe 2+ in the octahedral site. This is because the ionic radius</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1067063.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1067063.pdf"><span>The Level of Creative Abilities Dimensions According to Torrance Formal Test (B) and Their Relationship with Some Variables (Sex, Age, <span class="hlt">GPA</span>)</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Awamleh, Habis; Al Farah, Yacoub; El-Zraigat, Ibrahim</p> <p>2012-01-01</p> <p>This study aimed to identify the level of dimensions for creative abilities (originality, flexibility, originality, elaboration) among students in Al Rai Jordanian schools according to Torrance Formal test, and to investigate the differences in these levels attributable to the study variables (gender, age, grade point average "<span class="hlt">GPA</span>"). The…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22415322-structure-co-sub-hydrate-between-gpa','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22415322-structure-co-sub-hydrate-between-gpa"><span>The structure of CO{sub 2} hydrate between 0.7 and 1.0 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Tulk, C. A.; Molaison, J. J.; Machida, S.</p> <p></p> <p>A deuterated sample of CO{sub 2} structure I (sI) clathrate hydrate (CO{sub 2}·8.3 D{sub 2}O) has been formed and neutron diffraction experiments up to 1.0 <span class="hlt">GPa</span> at 240 K were performed. The sI CO{sub 2} hydrate transformed at 0.7 <span class="hlt">GPa</span> into the high pressure phase that had been observed previously by Hirai et al. [J. Phys. Chem. 133, 124511 (2010)] and Bollengier et al. [Geochim. Cosmochim. Acta 119, 322 (2013)], but which had not been structurally identified. The current neutron diffraction data were successfully fitted to a filled ice structure with CO{sub 2} molecules filling the water channels. This CO{submore » 2}+water system has also been investigated using classical molecular dynamics and density functional ab initio methods to provide additional characterization of the high pressure structure. Both models indicate the water network adapts a MH-III “like” filled ice structure with considerable disorder of the orientations of the CO{sub 2} molecule. Furthermore, the disorder appears to be a direct result of the level of proton disorder in the water network. In contrast to the conclusions of Bollengier et al., our neutron diffraction data show that the filled ice phase can be recovered to ambient pressure (0.1 MPa) at 96 K, and recrystallization to sI hydrate occurs upon subsequent heating to 150 K, possibly by first forming low density amorphous ice. Unlike other clathrate hydrate systems, which transform from the sI or sII structure to the hexagonal structure (sH) then to the filled ice structure, CO{sub 2} hydrate transforms directly from the sI form to the filled ice structure.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14..659S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14..659S"><span>Phase relations in the hydrous CMAS pyrolite in presence of KCl at 2 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Safonov, O.</p> <p>2012-04-01</p> <p>In the upper mantle, chlorides are constituents of concentrated aqueous solutions (brines), as well as chloride-carbonate and carbonatite melts. Mineral assemblages coming from diverse depth levels show that mobile (K, Na)Cl-bearing fluids are able to provoke intensive metasomatism of the peridotitic mantle accompanied by melting. Scarce experimental studies on influence of brines on mineral equilibria in the peridotitic mantle (Stalder et al., 2008; Chu et al., 2011) indicate that influence of chlorides on water activity in a fluid equilibrated with forsterite enstatite at pressures above 2 <span class="hlt">GPa</span> is very similar to their effect at lower "crustal" pressures (e.g. Aranovich, Newton, 1997): decrease of the H2O activity with an increase of the salt content results in an increase of the melting temperature of silicates. Nevertheless, these experiments were performed in the Al-free systems. Presence of Al would provoke an active interaction of alkali chlorides, namely KCl, with silicates with formation of new K-Al-bearing phases, such as phlogopite (in presence of H2O), which would influence on the melting of complex assemblages. In order to investigate an effect of KCl on phase relations in the Al2O3, CaO, Na2O-rich hydrous peridotite and on stability of garnet, pyroxenes, and amphiboles, in particular, experiments on interaction of the model CMAS pyrolite Fo57En17Prp14Di12 (+0.3 wt. % of Na2O) with the H2O-KCl fluid were performed at 2 <span class="hlt">GPa</span> in the temperature interval 900-1200. Mixtures of synthetic forsterite, diopside, enstatite and pyrope in the above weight ratio were mixed with 14 wt. % of Mg(OH)2 corresponding to 4.4 wt. % of H2O in the system. 2.4, 3.7, 5 and 10 wt. % of KCl were added to silicate-H2O mixture. Experiments were performed using a piston-cylinder apparatus with ½-inch talc high-pressure cells calibrated via brucite = periclase + H2O and albite = jadeite + quartz equilibria curves. Temperature was controlled with accuracy ?1 with the W95Re5/W80Re20</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMMR33A4332P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMMR33A4332P"><span>Structure and Thermal Behavior of CO2-IV at 18 <span class="hlt">GPa</span> from 300-625 K</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Palaich, S.; Tulk, C. A.; Molaison, J. J.; Makhluf, A. R.; Guthrie, M.; Kavner, A.; Manning, C. E.</p> <p>2014-12-01</p> <p>The study of the structure of solid CO2 at elevated pressures is important in condensed matter physics and material science, as well as geophysics—especially in understanding the structure of the interiors of planetary bodies. The high-pressure phases, including CO2-IV, and their stability between CO2-I (dry ice, the CO2 phase stable at ambient P,T) and polyhedrally bonded CO2-V are poorly characterized. Yoo et al. (2001, PRL, 86, 3) and Park et al. (2003, Phys Rev B, 68,1) concluded that the CO2 molecule is bent in phase IV, with C=O bond lengths of up to 1.3-1.5 Å, longer than the 1.168 Å in CO2-I. In contrast, Gorelli et al. (2004, PRL, 93, 20) and Datchi et al. (2009, PRL, 103, 18) inferred that the CO2 molecule in phase IV is linear, and the double-bond length is nearly identical to that of CO2-I. The studies also disagree on the structure of CO2-IV: tetragonal P41212, orthorhombic Pbcn and rhombohedral R-3c have all been reported. We performed neutron diffraction experiments at SNAP, Spallation Neutron Source, ORNL. The powder sample was pressurized to 18.0(2) <span class="hlt">GPa</span> at ambient temperature in a panoramic DAC. The resistive heating system was then heated to 625 K. Temperature was adjusted to 525 K, 450 K, 375 K and 300 K to study the thermal expansion of CO2-IV and provide data for a P,T equation of state. At 18 <span class="hlt">GPa</span> and 625 K the structure of CO2-IV is well indexed by the R-3c structure found by Datchi et al. (2009, PRL, 103, 18). The rhombohedral symmetry was retained as temperature was lowered through the proposed stability fields of both CO2-II and CO2-III to 300 K. Structure determination yielded aH = 8.532(6) Å, cH = 10.48(2) Å, V = 660.9(3) Å3, and ρ = 2.653 g cm-3 at 300 K and 18 <span class="hlt">GPa</span>. Preliminary linear thermal expansion parameters using the Holland-Powell (1998, J Metamorph Geol, 16, 3) model range from 5.7(6) x 10-6 K-1 to 1.39(1) x 10-5 K-1 for the lattice planes indexed. A fit to the volume yields a thermal expansion of 3.530(2) x 10-5 K-1</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT........57R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT........57R"><span>Application of nanoscopic dynamic mechanical <span class="hlt">analysis</span> for evaluating the mechanical behavior of hard tissues and bonded interfaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ryou, Heonjune</p> <p>2011-12-01</p> <p>In this study Dynamic Mechanical <span class="hlt">Analysis</span> (DMA) was applied to dentin, the macro hybrid layer and intact hybrid layers of the bonded dental restorative interface using nanoindentation. Both intertubular and peritubular dentin were evaluated by DMA using discrete and scanning mode nanoindentation. The complex (E*), loss (E"), and storage (E') moduli were quantified over a range of indentation loads and scanning frequencies. The storage modulus of the peritubular cuff (22.19 <span class="hlt">GPa</span><E'<34.71 <span class="hlt">GPa</span>) was significantly greater (p<0.001) than that for the intertubular dentin (16.08 <span class="hlt">GPa</span><E'<22.79 <span class="hlt">GPa</span>) over the range of frequencies, as expected, due to the higher relative mineral content. While the loss modulus of the intertubular dentin (1.31 <span class="hlt">GPa</span><E''<2.28 <span class="hlt">GPa</span>) was greater than that of the peritubular cuffs (0.70 <span class="hlt">GPa</span><E''<1.60 <span class="hlt">GPa</span>), the differences were not significant (p>0.05). A model bonded interface (i.e. the macro hybrid) was evaluated using scanning DMA. A new approach for hydrating samples using ethylene glycol solution was developed and then applied to identify the importance of hydration on the measured properties. Fully hydrated samples exhibited mean values of E*, E' and E" of 3.54 <span class="hlt">GPa</span>, 3.42 <span class="hlt">GPa</span> and 0.86 <span class="hlt">GPa</span>, respectively, whereas fully dehydrated samples exhibited values of 4.01 <span class="hlt">GPa</span>, 3.88 <span class="hlt">GPa</span> and 0.94 <span class="hlt">GPa</span>, respectively. There were significant differences in the complex modulus (p<0.05) and storage modulus (p<0.001) between the hydrated and dehydrated conditions. However, differences in the loss moduli with hydration were not significantly different (p>0.05). A dynamic loading frequency of 100 Hz and scanning frequency of 0.2 Hz were identified to provide the most reliable results in scanning the collagen-based systems. Lastly, the optimal testing parameters obtained from studying the macro hybrid layer were used to evaluate intact resin-dentin bonded interfaces. The property maps clearly distinguished variations in properties as a function of the constituents. It was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMMR31B0447T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMMR31B0447T"><span>The principal Hugoniot of Mg2SiO4 to 950 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Townsend, J. P.; Root, S.; Shulenburger, L.; Lemke, R. W.; Kraus, R. G.; Jacobsen, S. B.; Spaulding, D.; Davies, E.; Stewart, S. T.</p> <p>2017-12-01</p> <p>We present new measurements and ab-initio calculations of the principal Hugoniot states of forsterite Mg2SiO4 in the liquid regime between 200-950 <span class="hlt">GPa</span>.Forsterite samples were shock compressed along the principal Hugoniot using plate-impact shock compression experiments on the Sandia National Laboratories Z machine facility.In order to gain insight into the physical state of the liquid, we performed quantum molecular dynamics calculations of the Hugoniot and compare the results to experiment.We show that the principal Hugoniot is consistent with that of a single molecular fluid phase of Mg2SiO4, and compare our results to previous dynamic compression experiments and QMD calculations.Finally, we discuss how the results inform planetary accretion and impact models.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24694027','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24694027"><span>Soya bean Gα proteins with distinct biochemical properties exhibit differential ability to complement Saccharomyces cerevisiae <span class="hlt">gpa</span>1 mutant.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roy Choudhury, Swarup; Wang, Yuqi; Pandey, Sona</p> <p>2014-07-01</p> <p>Signalling pathways mediated by heterotrimeric G-proteins are common to all eukaryotes. Plants have a limited number of each of the G-protein subunits, with the most elaborate G-protein network discovered so far in soya bean (Glycine max, also known as soybean) which has four Gα, four Gβ and ten Gγ proteins. Biochemical characterization of Gα proteins from plants suggests significant variation in their properties compared with the well-characterized non-plant proteins. Furthermore, the four soya bean Gα (GmGα) proteins exhibit distinct biochemical activities among themselves, but the extent to which such biochemical differences contribute to their in vivo function is also not known. We used the yeast <span class="hlt">gpa</span>1 mutant which displays constitutive signalling and growth arrest in the pheromone-response pathway as an in vivo model to evaluate the effect of distinct biochemical activities of GmGα proteins. We showed that specific GmGα proteins can be activated during pheromone-dependent receptor-mediated signalling in yeast and they display different strengths towards complementation of yeast <span class="hlt">gpa</span>1 phenotypes. We also identified amino acids that are responsible for differential complementation abilities of specific Gα proteins. These data establish that specific plant Gα proteins are functional in the receptor-mediated pheromone-response pathway in yeast and that the subtle biochemical differences in their activity are physiologically relevant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22617086-critical-temperature-metallic-hydrogen-sulfide-gpa-pressure','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22617086-critical-temperature-metallic-hydrogen-sulfide-gpa-pressure"><span>Critical temperature of metallic hydrogen sulfide at 225-<span class="hlt">GPa</span> pressure</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kudryashov, N. A.; Kutukov, A. A.; Mazur, E. A., E-mail: EAMazur@mephi.ru</p> <p>2017-01-15</p> <p>The Eliashberg theory generalized for electron—phonon systems with a nonconstant density of electron states and with allowance made for the frequency behavior of the electron mass and chemical potential renormalizations is used to study T{sub c} in the SH{sub 3} phase of hydrogen sulfide under pressure. The phonon contribution to the anomalous electron Green’s function is considered. The pairing within the total width of the electron band and not only in a narrow layer near the Fermi surface is taken into account. The frequency and temperature dependences of the complex mass renormalization ReZ(ω), the density of states N(ε) renormalized bymore » the electron—phonon interactions, and the electron—phonon spectral function obtained computationally are used to calculate the anomalous electron Green’s function. A generalized Eliashberg equation with a variable density of electron states has been solved. The frequency dependence of the real and imaginary parts of the order parameter in the SH{sub 3} phase has been obtained. The value of T{sub c} ≈ 177 K in the SH{sub 3} phase of hydrogen sulfide at pressure P = 225 <span class="hlt">GPa</span> has been determined by solving the system of Eliashberg equations.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPA....6c5214J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPA....6c5214J"><span>Raman scattering of 2H-MoS2 at simultaneous high temperature and high pressure (up to 600 K and 18.5 <span class="hlt">GPa</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, JianJun; Li, HePing; Dai, LiDong; Hu, HaiYing; Zhao, ChaoShuai</p> <p>2016-03-01</p> <p>The Raman spectroscopy of natural molybdenite powder was investigated at simultaneous conditions of high temperature and high pressure in a heatable diamond anvil cell (DAC), to obtain the temperature and pressure dependence of the main Raman vibrational modes (E1g, E2 g 1 ,A1g, and 2LA(M)). Over our experimental temperature and pressure range (300-600 K and 1 atm-18.5 <span class="hlt">GPa</span>), the Raman modes follow a systematic blue shift with increasing pressure, and red shift with increasing temperature. The results were calculated by three-variable linear fitting. The mutual correlation index of temperature and pressure indicates that the pressure may reduce the temperature dependence of Raman modes. New Raman bands due to structural changes emerged at about 3-4 <span class="hlt">GPa</span> lower than seen in previous studies; this may be caused by differences in the pressure hydrostaticity and shear stress in the sample cell that promote the interlayer sliding.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27604269','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27604269"><span>Classification of Bacillus and Brevibacillus species using rapid <span class="hlt">analysis</span> of lipids by mass spectrometry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>AlMasoud, Najla; Xu, Yun; Trivedi, Drupad K; Salivo, Simona; Abban, Tom; Rattray, Nicholas J W; Szula, Ewa; AlRabiah, Haitham; Sayqal, Ali; Goodacre, Royston</p> <p>2016-11-01</p> <p>Bacillus are aerobic spore-forming bacteria that are known to lead to specific diseases, such as anthrax and food poisoning. This study focuses on the characterization of these bacteria by the detection of lipids extracted from 33 well-characterized strains from the Bacillus and Brevibacillus genera, with the aim to discriminate between the different species. For the purpose of analysing the lipids extracted from these bacterial samples, two rapid physicochemical techniques were used: matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) and liquid chromatography in conjunction with mass spectrometry (LC-MS). The findings of this investigation confirmed that MALDI-TOF-MS could be used to identify different bacterial lipids and, in combination with appropriate chemometrics, allowed for the discrimination between these different bacterial species, which was supported by LC-MS. The average correct classification rates for the seven species of bacteria were 62.23 and 77.03 % based on MALDI-TOF-MS and LC-MS data, respectively. The <span class="hlt">Procrustes</span> distance for the two datasets was 0.0699, indicating that the results from the two techniques were very similar. In addition, we also compared these bacterial lipid MALDI-TOF-MS profiles to protein profiles also collected by MALDI-TOF-MS on the same bacteria (<span class="hlt">Procrustes</span> distance, 0.1006). The level of discrimination between lipids and proteins was equivalent, and this further indicated the potential of MALDI-TOF-MS <span class="hlt">analysis</span> as a rapid, robust and reliable method for the classification of bacteria based on different bacterial chemical components. Graphical abstract MALDI-MS has been successfully developed for the characterization of bacteria at the subspecies level using lipids and benchmarked against HPLC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24238735','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24238735"><span>Associations between baccalaureate nursing students' perceptions of educational environment and HESI scores and <span class="hlt">GPA</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Payne, Leslie K; Glaspie, Tina</p> <p>2014-06-01</p> <p>Students' perceptions of their educational environment have been found to be related to their approaches to learning and learning outcomes. Educational environment is just beginning to be researched in nursing education with the vast majority of studies focusing on the clinical educational environment. Perception of educational environment has been shown to influence student implementation of a specific learning style and influences educational outcomes such as program completion and <span class="hlt">GPA</span>. There is a need for sound research that explores the relationship, if any, between perceptions of environment and outcomes. To explore the relationship between baccalaureate nursing student (BSN) perception of educational environment (SPEE) and objective learning outcomes. Retrospective correlational descriptive study. Private School of Nursing in the Southwest. Convenience sample of 62 graduating baccalaureate students. All graduating BSN students were invited to complete the Dundee Ready Education Environment Measure (DREEM) through the online survey application Qualtrics. A total of 62 students completed the DREEM survey. These results were compared with each student's <span class="hlt">GPA</span> and HESI score. A total of 62 students completed the survey for an overall response rate of 57%. There was no correlation between total SPEE and nursing grade point average (NGPA) or HESI exit scores. Based on this study at this institution, it appears that students' performance was not influenced by SPEE. One of the major implications of this study is the possibility that an "acceptable" SPEE (one that is neither exceptional nor terrible) may not significantly influence student outcomes. Exploring this relationship has theoretical as well as practical implications as educators seek to determine the effectiveness of educational interventions. Student perception of learning environment is measured in various ways at the majority of institutions. It has been assumed that an educational environment that is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5072710','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5072710"><span>Intra- and Interspecific Interactions as Proximate Determinants of Sexual Dimorphism and Allometric Trajectories in the Bottlenose Dolphin Tursiops truncatus (Cetacea, Odontoceti, Delphinidae)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2016-01-01</p> <p>Feeding adaptation, social behaviour, and interspecific interactions related to sexual dimorphism and allometric growth are particularly challenging to be investigated in the high sexual monomorphic Delphinidae. We used geometric morphometrics to extensively explore sexual dimorphism and ontogenetic allometry of different projections of the skull and the mandible of the bottlenose dolphin Tursiops truncatus. Two-dimensional landmarks were recorded on the dorsal, ventral, lateral, and occipital views of the skull, and on the lateral view of the left and the right mandible of 104 specimens from the Mediterranean and the North Seas, differing environmental condition and degree of interspecific associations. Landmark configurations were transformed, standardized and superimposed through a Generalized <span class="hlt">Procrustes</span> <span class="hlt">Analysis</span>. Size and shape differences between adult males and females were respectively evaluated through ANOVA on centroid size, <span class="hlt">Procrustes</span> ANOVA on <span class="hlt">Procrustes</span> distances, and MANOVA on <span class="hlt">Procrustes</span> coordinates. Ontogenetic allometry was investigated by multivariate regression of shape coordinates on centroid size in the largest homogenous sample from the North Sea. Results evidenced sexual dimorphic asymmetric traits only detected in the adults of the North Sea bottlenose dolphins living in monospecific associations, with females bearing a marked incision of the cavity hosting the left tympanic bulla. These differences were related to a more refined echolocalization system that likely enhances the exploitation of local resources by philopatric females. Distinct shape in immature versus mature stages and asymmetric changes in postnatal allometry of dorsal and occipital traits, suggest that differences between males and females are established early during growth. Allometric growth trajectories differed between males and females for the ventral view of the skull. Allometric trajectories differed among projections of skull and mandible, and were related to dietary</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29024568','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29024568"><span>Word maturity indices with latent semantic <span class="hlt">analysis</span>: why, when, and where is <span class="hlt">Procrustes</span> rotation applied?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jorge-Botana, Guillermo; Olmos, Ricardo; Luzón, José M</p> <p>2018-01-01</p> <p>The aim of this paper is to describe and explain one useful computational methodology to model the semantic development of word representation: Word maturity. In particular, the methodology is based on the longitudinal word monitoring created by Kirylev and Landauer using latent semantic <span class="hlt">analysis</span> for the representation of lexical units. The paper is divided into two parts. First, the steps required to model the development of the meaning of words are explained in detail. We describe the technical and theoretical aspects of each step. Second, we provide a simple example of application of this methodology with some simple tools that can be used by applied researchers. This paper can serve as a user-friendly guide for researchers interested in modeling changes in the semantic representations of words. Some current aspects of the technique and future directions are also discussed. WIREs Cogn Sci 2018, 9:e1457. doi: 10.1002/wcs.1457 This article is categorized under: Computer Science > Natural Language Processing Linguistics > Language Acquisition Psychology > Development and Aging. © 2017 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040087909&hterms=movement&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmovement','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040087909&hterms=movement&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmovement"><span>Coordinated turn-and-reach movements. II. Planning in an external frame of reference</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pigeon, Pascale; Bortolami, Simone B.; DiZio, Paul; Lackner, James R.</p> <p>2003-01-01</p> <p>The preceding study demonstrated that normal subjects compensate for the additional interaction torques generated when a reaching movement is made during voluntary trunk rotation. The present paper assesses the influence of trunk rotation on finger trajectories and on interjoint coordination and determines whether simultaneous turn-and-reach movements are most simply described relative to a trunk-based or an external reference frame. Subjects reached to targets requiring different extents of arm joint and trunk rotation at a natural pace and quickly in normal lighting and in total darkness. We first examined whether the larger interaction torques generated during rapid turn-and-reach movements perturb finger trajectories and interjoint coordination and whether visual feedback plays a role in compensating for these torques. These issues were addressed using generalized <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> (<span class="hlt">GPA</span>), which attempts to overlap a group of configurations (e.g., joint trajectories) through translations and rotations in multi-dimensional space. We first used <span class="hlt">GPA</span> to identify the mean intrinsic patterns of finger and joint trajectories (i.e., their average shape irrespective of location and orientation variability in the external and joint workspaces) from turn-and-reach movements performed in each experimental condition and then calculated their curvatures. We then quantified the discrepancy between each finger or joint trajectory and the intrinsic pattern both after <span class="hlt">GPA</span> was applied individually to trajectories from a pair of experimental conditions and after <span class="hlt">GPA</span> was applied to the same trajectories pooled together. For several subjects, joint trajectories but not finger trajectories were more curved in fast than slow movements. The curvature of both joint and finger trajectories of turn-and-reach movements was relatively unaffected by the vision conditions. Pooling across speed conditions significantly increased the discrepancy between joint but not finger trajectories for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4948315','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4948315"><span>Dynamic X-ray diffraction observation of shocked solid iron up to 170 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Denoeud, Adrien; Ozaki, Norimasa; Benuzzi-Mounaix, Alessandra; Uranishi, Hiroyuki; Kondo, Yoshihiko; Kodama, Ryosuke; Brambrink, Erik; Ravasio, Alessandra; Bocoum, Maimouna; Boudenne, Jean-Michel; Harmand, Marion; Guyot, François; Mazevet, Stephane; Riley, David; Makita, Mikako; Sano, Takayoshi; Sakawa, Youichi; Inubushi, Yuichi; Gregori, Gianluca; Koenig, Michel; Morard, Guillaume</p> <p>2016-01-01</p> <p>Investigation of the iron phase diagram under high pressure and temperature is crucial for the determination of the composition of the cores of rocky planets and for better understanding the generation of planetary magnetic fields. Here we present X-ray diffraction results from laser-driven shock-compressed single-crystal and polycrystalline iron, indicating the presence of solid hexagonal close-packed iron up to pressure of at least 170 <span class="hlt">GPa</span> along the principal Hugoniot, corresponding to a temperature of 4,150 K. This is confirmed by the agreement between the pressure obtained from the measurement of the iron volume in the sample and the inferred shock strength from velocimetry deductions. Results presented in this study are of the first importance regarding pure Fe phase diagram probed under dynamic compression and can be applied to study conditions that are relevant to Earth and super-Earth cores. PMID:27357672</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24098042','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24098042"><span>Learning style preferences of first-year dental students at King Saud University in Riyadh, Saudi Arabia: influence of gender and <span class="hlt">GPA</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Al-Saud, Loulwa Mohammed Saad</p> <p>2013-10-01</p> <p>The aim of this study was to investigate the learning style preferences of a group of first-year dental students and their relation to gender and past academic performance. A total of 113 first-year dental students (forty-two female, seventy-one male) at King Saud University in Riyadh, Saudi Arabia, participated. The Visual, Aural, Read-write, and Kinesthetic (VARK) questionnaire was used to determine the students' preferred mode of learning. This sixteen-item questionnaire defines preference of learning based on the sensory modalities: visual, aural, reading/writing, and kinesthetic. More than half (59 percent) of the students were found to have multimodal learning preferences. The most common single learning preferences were aural (20 percent) followed by kinesthetic (15.2 percent). Gender differences were not statistically significant. However, a statistically significant difference was found in the mean values of <span class="hlt">GPA</span> in relation to the students' learning style preferences (p=0.019). Students with a single learning style preference had a lower mean <span class="hlt">GPA</span> than those with multiple (quad-modal) learning style preferences. For effective instruction, dental educators need to broaden their range of presentation styles to help create more positive and effective learning environments for all students.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=sex+AND+gender+AND+discrimination&pg=5&id=EJ934344','ERIC'); return false;" href="https://eric.ed.gov/?q=sex+AND+gender+AND+discrimination&pg=5&id=EJ934344"><span>Multiple Mechanisms in the Perception of Face Gender: Effect of Sex-Irrelevant Features</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Komori, Masashi; Kawamura, Satoru; Ishihara, Shigekazu</p> <p>2011-01-01</p> <p>Effects of sex-relevant and sex-irrelevant facial features on the evaluation of facial gender were investigated. Participants rated masculinity of 48 male facial photographs and femininity of 48 female facial photographs. Eighty feature points were measured on each of the facial photographs. Using a generalized <span class="hlt">Procrustes</span> <span class="hlt">analysis</span>, facial shapes…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018CoMP..173...22S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018CoMP..173...22S"><span>Interaction of peridotite with Ca-rich carbonatite melt at 3.1 and 6.5 <span class="hlt">GPa</span>: Implication for merwinite formation in upper mantle, and for the metasomatic origin of sublithospheric diamonds with Ca-rich suite of inclusions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharygin, Igor S.; Shatskiy, Anton; Litasov, Konstantin D.; Golovin, Alexander V.; Ohtani, Eiji; Pokhilenko, Nikolay P.</p> <p>2018-03-01</p> <p>We performed an experimental study, designed to reproduce the formation of an unusual merwinite + olivine-bearing mantle assemblage recently described as a part of a Ca-rich suite of inclusions in sublithospheric diamonds, through the interaction of peridotite with an alkali-rich Ca-carbonatite melt, derived from deeply subducted oceanic crust. In the first set of experiments, we studied the reaction between powdered Mg-silicates, olivine and orthopyroxene, and a model Ca-carbonate melt (molar Na:K:Ca = 1:1:2), in a homogeneous mixture, at 3.1 and 6.5 <span class="hlt">GPa</span>. In these equilibration experiments, we observed the formation of a merwinite + olivine-bearing assemblage at 3.1 <span class="hlt">GPa</span> and 1200 °C and at 6.5 <span class="hlt">GPa</span> and 1300-1400 °C. The melts coexisting with this assemblage have a low Si and high Ca content (Ca# = molar 100 × Ca/(Ca + Mg) > 0.57). In the second set of experiments, we investigated reaction rims produced by interaction of the same Ca-carbonate melt (molar Na:K:Ca = 1:1:2) with Mg-silicate, olivine and orthopyroxene, single crystals at 3.1 <span class="hlt">GPa</span> and 1300 °C and at 6.5 <span class="hlt">GPa</span> and 1400 °C. The interaction of the Ca-carbonate melt with olivine leads to merwinite formation through the expected reaction: 2Mg2SiO4 (olivine) + 6CaCO3 (liquid) = Ca3MgSi2O8 (merwinite) + 3CaMg(CO3)2 (liquid). Thus, our experiments confirm the idea that merwinite in the upper mantle may originate via interaction of peridotite with Ca-rich carbonatite melt, and that diamonds hosting merwinite may have a metasomatic origin. It is remarkable that the interaction of the Ca-carbonate melt with orthopyroxene crystals does not produce merwinite both at 3.1 and 6.5 <span class="hlt">GPa</span>. This indicates that olivine grain boundaries are preferable for merwinite formation in the upper mantle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24025237','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24025237"><span>Clapeyron slope reversal in the melting curve of AuGa2 at 5.5 <span class="hlt">GPa</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Geballe, Z M; Raju, S V; Godwal, B K; Jeanloz, R</p> <p>2013-10-16</p> <p>We use x-ray diffraction in a resistively heated diamond anvil cell to extend the melting curve of AuGa2 beyond its minimum at 5.5 <span class="hlt">GPa</span> and 720 K, and to constrain the high-temperature phase boundaries between cubic (fluorite structure), orthorhombic (cottunite structure) and monoclinic phases. We document a large change in Clapeyron slope that coincides with the transitions from cubic to lower symmetry phases, showing that a structural transition is the direct cause of the change in slope. In addition, moderate (~30 K) to large (90 K) hysteresis is detected between melting and freezing, from which we infer that at high pressures, AuGa2 crystals can remain in a metastable state at more than 5% above the thermodynamic melting temperature.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeCoA.224..327K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeCoA.224..327K"><span>Effect of pressure on the short-range structure and speciation of carbon in alkali silicate and aluminosilicate glasses and melts at high pressure up to 8 <span class="hlt">GPa</span>: 13C, 27Al, 17O and 29Si solid-state NMR study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Eun Jeong; Fei, Yingwei; Lee, Sung Keun</p> <p>2018-03-01</p> <p>Despite the pioneering efforts to explore the nature of carbon in carbon-bearing silicate melts under compression, experimental data for the speciation and the solubility of carbon in silicate melts above 4 <span class="hlt">GPa</span> have not been reported. Here, we explore the speciation of carbon and pressure-induced changes in network structures of carbon-bearing silicate (Na2O-3SiO2, NS3) and sodium aluminosilicate (NaAlSi3O8, albite) glasses quenched from melts at high pressure up to 8 <span class="hlt">GPa</span> using multi-nuclear solid-state NMR. The 27Al triple quantum (3Q) MAS NMR spectra for carbon-bearing albite melts revealed the pressure-induced increase in the topological disorder around 4 coordinated Al ([4]Al) without forming [5,6]Al. These structural changes are similar to those in volatile-free albite melts at high pressure, indicating that the addition of CO2 in silicate melts may not induce any additional increase in the topological disorder around Al at high pressure. 13C MAS NMR spectra for carbon-bearing albite melts show multiple carbonate species, including [4]Si(CO3)[4]Si, [4]Si(CO3)[4]Al, [4]Al(CO3)[4]Al, and free CO32-. The fraction of [4]Si(CO3)[4]Al increases with increasing pressure, while those of other bridging carbonate species decrease, indicating that the addition of CO2 may enhance mixing of Si and Al at high pressure. A noticeable change is not observed for 29Si NMR spectra for the carbon-bearing albite glasses with varying pressure at 1.5-6 <span class="hlt">GPa</span>. These NMR results confirm that the densification mechanisms established for fluid-free, polymerized aluminosilicate melts can be applied to the carbon-bearing albite melts at high pressure. In contrast, the 29Si MAS NMR spectra for partially depolymerized, carbon-bearing NS3 glasses show that the fraction of [5,6]Si increases with increasing pressure at the expense of Q3 species ([4]Si species with one non-bridging oxygen as the nearest neighbor). The pressure-induced increase in topological disorder around Si is evident from an</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DokES.477.1483S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DokES.477.1483S"><span>Synthesis of hydrocarbons by CO2 fluid conversion with hydrogen: Experimental modeling at 7.8 <span class="hlt">GPa</span> and 1350°C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sokol, A. G.; Tomilenko, A. A.; Bul'bak, T. A.; Sobolev, N. V.</p> <p>2017-12-01</p> <p>Synthesis of hydrocarbons by the interaction of a CO2 fluid with hydrogen mantle domains has been simulated in an experiment at 7.8 <span class="hlt">GPa</span> and 1350°C. The synthesized fluid contains mainly aldehydes; lower amounts of ketones, alcohols, esters, and ethers; as well as noticeable amounts of isobutane and butane, alkenes, arenes, and polycyclic aromatic and heterocyclic hydrocarbons. The fluid is compositionally close to volatiles found in inclusions from mantle olivines and picroilmenites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMMR33A2304C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMMR33A2304C"><span>Bromine speciation in hydrous haplogranitic melts up to 7 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cochain, B.; de Grouchy, C.; Crepisson, C.; Kantor, I.; Irifune, T.; Sanloup, C.</p> <p>2013-12-01</p> <p>Halogens are minor volatiles in the Earth's mantle and crust, but they have significant and specific influences on magmatic and degassing processes. They also provide insights about subsurface magma movement and eruption likelihood in subduction-related volcanism. Their speciation in silicate melts affects volatile exsolution, rheology, and the thermodynamic properties of the melts but still remains relatively unknown. A few studies have explored halogen speciation at room conditions, i.e. in glasses but no firm conclusion has yet been reached. Furthermore, halogen speciation remains unexplored at high pressures and temperatures. In this work we investigate the speciation of Br in subduction-related melt (hydrous haplogranite melt) up to 1200°C and 7 <span class="hlt">GPa</span> using X-ray absorption spectroscopy (XANES and EXAFS) at the Br K-edge. High P-T conditions were generated by the Paris-Edinburgh press. The use of nanocrystalline diamond capsules enabled us to avoid glitches in the EXAFS spectra. The results provide valuable information on Br speciation and its evolution with pressure. It gives insights into solubility mechanisms for halogens in magmas at depth and on their degassing from the melt. In addition, we were able to identify quench effects on the atomic environment of Br by comparison of high P-T in-situ spectra and ex-situ spectra recorded on quenched samples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ISPAr.XL7.1269M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ISPAr.XL7.1269M"><span>Comparison of Unsupervised Vegetation Classification Methods from Vhr Images after Shadows Removal by Innovative Algorithms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Movia, A.; Beinat, A.; Crosilla, F.</p> <p>2015-04-01</p> <p>The recognition of vegetation by the <span class="hlt">analysis</span> of very high resolution (VHR) aerial images provides meaningful information about environmental features; nevertheless, VHR images frequently contain shadows that generate significant problems for the classification of the image components and for the extraction of the needed information. The aim of this research is to classify, from VHR aerial images, vegetation involved in the balance process of the environmental biochemical cycle, and to discriminate it with respect to urban and agricultural features. Three classification algorithms have been experimented in order to better recognize vegetation, and compared to NDVI index; unfortunately all these methods are conditioned by the presence of shadows on the images. Literature presents several algorithms to detect and remove shadows in the scene: most of them are based on the RGB to HSI transformations. In this work some of them have been implemented and compared with one based on RGB bands. Successively, in order to remove shadows and restore brightness on the images, some innovative algorithms, based on <span class="hlt">Procrustes</span> theory, have been implemented and applied. Among these, we evaluate the capability of the so called "not-centered oblique <span class="hlt">Procrustes</span>" and "anisotropic <span class="hlt">Procrustes</span>" methods to efficiently restore brightness with respect to a linear correlation correction based on the Cholesky decomposition. Some experimental results obtained by different classification methods after shadows removal carried out with the innovative algorithms are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhPl...24a0701X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhPl...24a0701X"><span>The magnetically driven plasma jet produces a pressure of 33 <span class="hlt">GPa</span> on PTS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Qiang; Dan, Jiakun; Wang, Guilin; Guo, Shuai; Zhang, Siqun; Cai, Hongchun; Ren, Xiao; Wang, Kunlun; Zhou, Shaotong; Zhang, Zhaohui; Huang, Xianbin</p> <p>2017-01-01</p> <p>We report on experiments in which a magnetically driven plasma jet was used to hit a 500 μm thick planar aluminum target. The plasma jet was produced by using a 50 μm thick aluminum radial foil, which was subjected to 4 MA, 90 ns rising time current on the primary test stand pulsed power facility. The subsequent magnetic bubbles propagate with radial velocity reaching 200 km/s and an axial velocity of 230 km/s. After the plasma knocks onto the target, a shock forms in the target. When the shock gets to the backside of the target, we measure the velocity of the moving surface using dual laser heterodyne velocimetry. By using the Hugoniot relations, we know that the plasma jet produced a pressure of 33 <span class="hlt">GPa</span>. According to the measured pressure and the velocity of the plasma jet, the density of the jet can be also roughly estimated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Litho.227..179Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Litho.227..179Z"><span>Evolution of diamond resorption in a silicic aqueous fluid at 1-3 <span class="hlt">GPa</span>: Application to kimberlite emplacement and mantle metasomatism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Zhihai; Fedortchouk, Yana; Hanley, Jacob J.</p> <p>2015-06-01</p> <p>Natural diamonds grow and partially dissolve during mantle metasomatism and undergo further resorption during the ascent to the Earth's surface in kimberlite magmas. This study uses atomic force microscopy (AFM) for quantitative characterization of diamond resorption morphology in order to provide robust constraints of the composition of kimberlitic and mantle metasomatic fluids. We performed experiments in a piston-cylinder apparatus at pressures (P) of 1-3 <span class="hlt">GPa</span> and temperatures (T) of 1150-1400 °C to examine the impact of P, T, and silica content of an aqueous fluid on diamond dissolution. Petrographic observation and microthermometry of synthetic fluid inclusions trapped in olivine at the run conditions provide constraints on the composition and density of the fluid reacting with the diamond. Our results confirm an inverse relationship between P and T on diamond dissolution kinetics. A P increase of 1 <span class="hlt">GPa</span> suppresses diamond oxidation rates by the same value as a T decrease by 50 °C, while the transformation rate of diamond crystal morphology from octahedron to tetrahexahedron increases with both P and T. All dissolved diamonds develop glossy surfaces, ditrigonal {111} faces, sheaf striations, and negative trigons, while circular pits only occur in aqueous fluids with low silica content (≤ 4.2 mol/kg) at 1 <span class="hlt">GPa</span>. We identify five distinct morphological groups of trigons: two types of point-bottomed (p/b) (trumpet- and V-shaped) and three types of flat-bottomed (f/b) (trumpet-shaped, trapezoid-shaped and rounded). AFM measurements of trigons from two successive runs showed three stages of their evolution. Etch pits nucleate at defects as trumpet p/b trigons with the vertical dissolution rate (Vd) faster than the dissolution rates at the surface free of defects; they further develop by growth of the bottoms in (111) plane to create trumpet-shaped f/b trigons accompanied by decrease in Vd; and finally form trapezoid-shaped f/b trigon with constant wall angles. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=ex+AND+post+AND+facto&pg=4&id=EJ1092901','ERIC'); return false;" href="https://eric.ed.gov/?q=ex+AND+post+AND+facto&pg=4&id=EJ1092901"><span>Impact of Delivery Modality, Student <span class="hlt">GPA</span>, and Time-Lapse since High School on Successful Completion of College-Level Math after Taking Developmental Math</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Acosta, Diane; North, Teresa Lynn; Avella, John</p> <p>2016-01-01</p> <p>This study considered whether delivery modality, student <span class="hlt">GPA</span>, or time since high school affected whether 290 students who had completed a developmental math series as a community college were able to successfully complete college-level math. The data used in the study was comprised of a 4-year period historical student data from Odessa College…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMMR21A2624G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMMR21A2624G"><span>Defining the Iron-Rich Fe-Ni-S Melting Curve at 20<span class="hlt">GPa</span>: Implications for Martian Core Solidification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gilfoy, F. G.; Li, J.</p> <p>2016-12-01</p> <p>In 1997, the Mars Global Surveyor detected strong remnant magnetization of 4 Ga impact basins in the planet's southern highlands (Acuna et al. 1999), but the dearth of strongly magnetized rocks younger than 4 Ga in age is interpreted as evidence cataloging the death of an early Martian dynamo (Stevenson, 2001; Fassett 2011). In order to investigate the thermal evolution of the Martian core and assess the possibility of iron "snow" core crystallization to restart the dynamo, a series of multi-anvil experiments have been conducted to define the iron-rich liquidus of the Fe-Ni-S system at 20 <span class="hlt">GPa</span>, the estimated pressure of the Martian core-mantle boundary (CMB), across its entire temperature range. Due to the fineness of features at high temperatures and low S concentrations, area <span class="hlt">analysis</span> techniques, in additional to traditional electron microprobe <span class="hlt">analysis</span>, were used to determine the composition of the experimental data. When fitted using an asymmetrical regular solution model, our data yields a liquidus that is significantly depressed when compared to calculations made assuming ideal behavior. Pronounced melting point depression at S contents corresponding to the likely composition of the Martian core means that the onset of crystallization will take much longer than previously thought. By comparing a calculated areotherm to liquidii interpolated between our experimental data and that from the literature, we find that the two intersect at the high-pressure end. Thus, the Martian core solidification is expected to begin at the center of planet and iron "snow" core crystallization is unlikely to occur within Mars .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMMR43A0457N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMMR43A0457N"><span>Raman Spectroscopy of Water-rich Stishovite and Dense High-Pressure Silica up to 55 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nisr, C.; Shim, S. H.; Leinenweber, K. D.; Chizmeshya, A. V.</p> <p>2017-12-01</p> <p>Recent studies have shown that mineral phases such as δ-AlOOH, (Mg,Si)OOH, (Mg,Si,Al)OOH, (Al,Si)O2 and SiO2 with rutile-type or modified rutile-type crystal structures can store large amounts of water and be stable at high pressure and high temperature relevant to the Earth's lower mantle. The Al-H charge coupled substitution has been proposed to explain the large storage capacity of these phases. However, the substitution cannot explain the large water storage found in pure stishovite (Spektor et al., 2011). Instead, an octahedral version of hydrogarnet-like substitution has been proposed for the incorporation of hydrogen in pure stishovite. We have performed Raman spectroscopy measurements on pure hydrous stishovite with 3.2 wt% water up to 55 <span class="hlt">GPa</span>. At ambient pressure, we found that the OH stretching mode frequencies range between those of low-water aluminous stishovite and δ-AlOOH, suggesting an intermediate strength of hydrogen bonding between these two phases. In the lattice mode range, we observe modes similar to the IR-active modes of anhydrous stishovite after decompression to 1 bar, suggesting Si defects in the crystal structure that activate the inactive modes. Our data show a series of changes at pressures between 24 and 28 <span class="hlt">GPa</span>, supporting our observation of a phase transition (likely to the CaCl2 type) in X-Ray diffraction measurements (Nisr et al., 2017, JGR). We found that the OH mode of hydrous stishovite has a positive frequency shift with an increase in pressure. The behavior is the opposite to that found in δ-AlOOH, indicating that the OH incorporation mechanism in hydrous silica is different from that of aluminous low-water stishovite and δ-AlOOH, likely through direct substitution (Si ⇄ 4H+). Because the mantle hydrous phases would have complex compositions, our study suggests that the direct substitution should also be considered together with the Al substitution for the deep mantle storage of water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010E%26PSL.289..479A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010E%26PSL.289..479A"><span>Sound velocity measurement in liquid water up to 25 <span class="hlt">GPa</span> and 900 K: Implications for densities of water at lower mantle conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Asahara, Yuki; Murakami, Motohiko; Ohishi, Yasuo; Hirao, Naohisa; Hirose, Kei</p> <p>2010-01-01</p> <p>We extended the pressure range of sound velocity measurements for liquid water to 25 <span class="hlt">GPa</span> and 900 K along the melting curve using a laser heated diamond anvil cell with a combined system of Brillouin scattering and synchrotron X-ray diffraction. Experimental pressure and temperature were obtained by solving simultaneous equations: the melting curve of ice and the equation of state for gold. The sound velocities obtained in liquid water at high pressures and melting temperatures were converted to density using Murnaghan's equation of state by fitting a parameter of the pressure derivative of bulk modulus at 1 <span class="hlt">GPa</span>. The results are in good agreement with the values predicted by a previously reported equation of state for water based on sound velocity measurements. The equation of state for water obtained in this study could be applicable to water released by dehydration reactions of dense hydrous magnesium silicate phases in cold subducting slabs at lower mantle conditions, although the validity of Murnaghan's equation of state for water should be evaluated in a wider pressure and temperature ranges. The present velocity data provides the basis for future improvement of the accurate thermodynamic model for water at high pressures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25411713','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25411713"><span>The skeletal maturation status estimated by statistical shape <span class="hlt">analysis</span>: axial images of Japanese cervical vertebra.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shin, S M; Kim, Y-I; Choi, Y-S; Yamaguchi, T; Maki, K; Cho, B-H; Park, S-B</p> <p>2015-01-01</p> <p>To evaluate axial cervical vertebral (ACV) shape quantitatively and to build a prediction model for skeletal maturation level using statistical shape <span class="hlt">analysis</span> for Japanese individuals. The sample included 24 female and 19 male patients with hand-wrist radiographs and CBCT images. Through generalized <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> and principal components (PCs) <span class="hlt">analysis</span>, the meaningful PCs were extracted from each ACV shape and analysed for the estimation regression model. Each ACV shape had meaningful PCs, except for the second axial cervical vertebra. Based on these models, the smallest prediction intervals (PIs) were from the combination of the shape space PCs, age and gender. Overall, the PIs of the male group were smaller than those of the female group. There was no significant correlation between centroid size as a size factor and skeletal maturation level. Our findings suggest that the ACV maturation method, which was applied by statistical shape <span class="hlt">analysis</span>, could confirm information about skeletal maturation in Japanese individuals as an available quantifier of skeletal maturation and could be as useful a quantitative method as the skeletal maturation index.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4614167','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4614167"><span>The skeletal maturation status estimated by statistical shape <span class="hlt">analysis</span>: axial images of Japanese cervical vertebra</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shin, S M; Choi, Y-S; Yamaguchi, T; Maki, K; Cho, B-H; Park, S-B</p> <p>2015-01-01</p> <p>Objectives: To evaluate axial cervical vertebral (ACV) shape quantitatively and to build a prediction model for skeletal maturation level using statistical shape <span class="hlt">analysis</span> for Japanese individuals. Methods: The sample included 24 female and 19 male patients with hand–wrist radiographs and CBCT images. Through generalized <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> and principal components (PCs) <span class="hlt">analysis</span>, the meaningful PCs were extracted from each ACV shape and analysed for the estimation regression model. Results: Each ACV shape had meaningful PCs, except for the second axial cervical vertebra. Based on these models, the smallest prediction intervals (PIs) were from the combination of the shape space PCs, age and gender. Overall, the PIs of the male group were smaller than those of the female group. There was no significant correlation between centroid size as a size factor and skeletal maturation level. Conclusions: Our findings suggest that the ACV maturation method, which was applied by statistical shape <span class="hlt">analysis</span>, could confirm information about skeletal maturation in Japanese individuals as an available quantifier of skeletal maturation and could be as useful a quantitative method as the skeletal maturation index. PMID:25411713</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28257561','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28257561"><span>Functional morphology of the douc langur (Pygathrix spp.) scapula.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bailey, Katie E; Lad, Susan E; Pampush, James D</p> <p>2017-06-01</p> <p>Most colobine monkeys primarily move through their arboreal environment quadrupedally. Douc langurs (Pygathrix spp.), however, are regularly observed to use suspensory behaviors at the Endangered Primate Rescue Center (EPRC) in Northern Vietnam. Previous work has linked variation in scapular morphology to different modes of primate arboreal locomotion. Here we investigate whether the shape of the Pygathrix scapula resembles obligate brachiators (gibbons) or obligate arboreal quadrupeds (other cercopithecoids). Using a MicroScribe G2X 3D digitizer, the positions of 17 landmarks were recorded on 15 different species of nonhuman primates (n = 100) from three categories of locomotor behavior: brachiator, arboreal quadruped, and unknown (Pygathrix). All analyses were conducted in the R package geomorph. A <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> uniformly scaled the shape data and placed specimens into the same morphospace. A Principal Component <span class="hlt">Analysis</span> was used to examine scapular shape and a <span class="hlt">Procrustes</span> ANOVA was conducted to test for shape difference in the scapulae. A pairwise <span class="hlt">analysis</span> was used to compare the means of the locomotor categories and identify any statistically significant differences. A phylogenetically controlled <span class="hlt">Procrustes</span> ANOVA was also conducted using a phylogeny from 10kTrees. Results show Pygathrix scapular morphology is significantly different from both arboreal colobine quadrupeds (p < 0.01) and hylobatid brachiators (p < 0.01). It does, however, share some features with each including a long vertebral border, like other cercopithecoids, and a more laterally projecting acromion process, like the hylobatids. The principal difference segregating Pygathrix from both the arboreal quadrupeds and the brachiators is the more medially placed superior angle. These nuanced morphological characteristics associated with suspensory behaviors may be useful for inferring suspensory locomotion in the primate fossil record. © 2017 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018350','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018350"><span>Hydrothermal studies in a new diamond anvil cell up to 10 <span class="hlt">GPa</span> and from -190°C to 1200°C</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bassett, William A.; Shen, A.H.; Bucknum, M.; Chou, I.-Ming</p> <p>1993-01-01</p> <p>The new hydrothermal diamond anvil cell (HDAC) has been designed for optical microscopy and X-ray diffraction at pressures up to 10 <span class="hlt">GPa</span> and temperatures between −190°C and 1200°C. Laser light reffected from the top and bottom anvil faces and the top and bottom solid sample faces produce interference fringes that provide a very sensitive means of monitoring the volume of sample chamber and for observing volume and refractive index changes in solid samples due to transitions and reactions. Synchrotron radiation has been used to make X-ray diffraction patterns of samples under hydrothermal conditions. Individual heaters and individual thermocouples provide temperature control with an accuracy of ±0.5°C. Liquid nitrogen directly introduced into the HDAC has been used to reduce the sample temperature to −190°C. The α-β phase boundary of quartz has been used to calculate the transition pressures from measured transition temperatures. With this method we have redetermined 5 isochores of H2O up to 850°C and 1.2 <span class="hlt">GPa</span> at which the solution rate of the quartz became so rapid that the quartz dissolved completely before the α-β transition could be observed. When silica solutions were cooled, opal spherules and rods formed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27109917','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27109917"><span>Sex determination by three-dimensional geometric morphometrics of the vault and midsagittal curve of the neurocranium in a modern Greek population sample.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chovalopoulou, Maria-Eleni; Valakos, Efstratios D; Manolis, Sotiris K</p> <p>2016-06-01</p> <p>The aim of this study is to assess sexual dimorphism of adult crania in the vault and midsagittal curve of the vault using three-dimensional geometric morphometric methods. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived during the 20th century in Greece. The three-dimensional co-ordinates of 31 ecto-cranial landmarks and 30 semi-landmarks were digitized using a MicroScribe 3DX contact digitizer. Generalized <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> (<span class="hlt">GPA</span>) was used to obtain size and shape variables for statistical <span class="hlt">analysis</span>. Shape, size and form analyses were carried out by logistic regression and three discriminant function analyses. Results indicate that there are shape differences between sexes. Females in the region of the parietal bones are narrower and the axis forming the frontal and occipital bones is more elongated; the frontal bone is more vertical. Sex-specific shape differences give better classification results in the vault (79%) compared with the midsagittal curve of the neurocranium (68.8%). Size alone yielded better results for cranial vault (82%), while for the midsagittal curve of the vault the result is poorer (68.1%). As anticipated, the classification accuracy improves when both size and shape are combined (89.2% for vault, and 79.4% for midsagittal curve of the vault). These latter findings imply that, in contrast to the midsagittal curve of the neurocranium, the shape of the cranial vault can be used as an indicator of sex in the modern Greek population. Copyright © 2016. Published by Elsevier GmbH.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7626E..09H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7626E..09H"><span>Statistical 3D shape <span class="hlt">analysis</span> of gender differences in lateral ventricles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Qing; Karpman, Dmitriy; Duan, Ye</p> <p>2010-03-01</p> <p>This paper aims at analyzing gender differences in the 3D shapes of lateral ventricles, which will provide reference for the <span class="hlt">analysis</span> of brain abnormalities related to neurological disorders. Previous studies mostly focused on volume <span class="hlt">analysis</span>, and the main challenge in shape <span class="hlt">analysis</span> is the required step of establishing shape correspondence among individual shapes. We developed a simple and efficient method based on anatomical landmarks. 14 females and 10 males with matching ages participated in this study. 3D ventricle models were segmented from MR images by a semiautomatic method. Six anatomically meaningful landmarks were identified by detecting the maximum curvature point in a small neighborhood of a manually clicked point on the 3D model. Thin-plate spline was used to transform a randomly selected template shape to each of the rest shape instances, and the point correspondence was established according to Euclidean distance and surface normal. All shapes were spatially aligned by Generalized <span class="hlt">Procrustes</span> <span class="hlt">Analysis</span>. Hotelling T2 twosample metric was used to compare the ventricle shapes between males and females, and False Discovery Rate estimation was used to correct for the multiple comparison. The results revealed significant differences in the anterior horn of the right ventricle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=risk+AND+return+AND+relationship&pg=5&id=EJ534267','ERIC'); return false;" href="https://eric.ed.gov/?q=risk+AND+return+AND+relationship&pg=5&id=EJ534267"><span>Suspended Students: An <span class="hlt">Analysis</span> of Suspension Length and Returning Semester <span class="hlt">GPA</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Meadows, Deana C.; Tharp, Terri J.</p> <p>1996-01-01</p> <p>A study at Middle Tennessee State University investigated the relationship between the length of a student's suspension from college and academic success upon return. <span class="hlt">Analysis</span> of academic records of 765 students suspended between fall 1991 and summer 1993 semesters then allowed to reenter the university within 1 year found suspension length…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA....14030G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA....14030G"><span>Elastic Properties of Synthetic Pyrope (Mg3Al2Si3O12) to 9 <span class="hlt">GPa</span> and 1000°C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gwanmesia, G. D.; Zhang, J.; Li, B.; Darling, K.; Kung, J.; Neuville, D.; Raterron, P.; Sullivan, S.; Liebermann, R. C.</p> <p>2003-04-01</p> <p>We have measured the elastic wave velocities of polycrystalline pyrope (Mg_3Al_2Si_3O12) to 9 <span class="hlt">GPa</span> and 1000^oC by ultrasonic interferometry, combined with in-situ synchrotron x-ray diffraction and imaging techniques. Fine-grained polycrystalline specimens (99.5% of theoretical density) were hot-pressed from a homogeneous glass starting material in the USSA-2000 apparatus at Stony Brook; the physical properties of the recovered specimens were characterized with density measurements, x-ray diffraction and transmission electron microscopy. Bench-top elastic wave velocities were in excellent agreement with the isotropic averages calculated from single-crystal elastic moduli of Leitner et al. (1980) by the Hashin-Shtrikman method. Travel times of acoustic compressional (P) and shear (S) waves, specimen lengths and PVT equations of state for the specimen and a NaCl standard were measured to 9 <span class="hlt">GPa</span> and 1000^oC in a DIA-type high pressure apparatus (SAM-85), installed on the superconducting wiggler beamline (X17B) at the National Synchrotron Light Source of the Brookhaven National Laboratory. These data enabled us to determine the pressure and temperature derivatives of the elastic wave velocities and moduli for isotropic pyrope. We compare our new values with those of previous investigators and discuss the implications of these data for interpreting the seismic velocity gradients in the transition zone of the Earth's mantle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22667628','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22667628"><span>Development of a simultaneous Hugoniot and temperature measurement for preheated-metal shock experiments: melting temperatures of Ta at pressures of 100 <span class="hlt">GPa</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Jun; Zhou, Xianming; Li, Jiabo; Wu, Qiang; Cai, Lingcang; Dai, Chengda</p> <p>2012-05-01</p> <p>Equations of state of metals are important issues in earth science and planetary science. A major limitation of them is the lack of experimental data for determining pressure-volume and temperature of shocked metal simultaneously. By measuring them in a single experiment, a major source of systematic error is eliminated in determining from which shock pressure release pressure originates. Hence, a non-contact fast optical method was developed and demonstrated to simultaneously measure a Hugoniot pressure-volume (P(H)-V(H)) point and interfacial temperature T(R) on the release of Hugoniot pressure (P(R)) for preheated metals up to 1000 K. Experimental details in our investigation are (i) a Ni-Cr resistance coil field placed around the metal specimen to generate a controllable and stable heating source, (ii) a fiber-optic probe with an optical lens coupling system and optical pyrometer with ns time resolution to carry out non-contact fast optical measurements for determining P(H)-V(H) and T(R). The shock response of preheated tantalum (Ta) at 773 K was investigated in our work. Measured data for shock velocity versus particle velocity at an initial state of room temperature was in agreement with previous shock compression results, while the measured shock data between 248 and 307 <span class="hlt">GPa</span> initially heated to 773 K were below the Hugoniot evaluation from its off-Hugoniot states. Obtained interfacial temperatures on release of Hugoniot pressures (100-170 <span class="hlt">GPa</span>) were in agreement with shock-melting points at initial ambient condition and ab initio calculations of melting curve. It indicates a good consistency for shock melting data of Ta at different initial temperatures. Our combined diagnostics for Hugoniot and temperature provides an important approach for studying EOS and the temperature effect of shocked metals. In particular, our measured melting temperatures of Ta address the current controversy about the difference by more than a factor of 2 between the melting</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12570505','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12570505"><span>Use of a wave reverberation technique to infer the density compression of shocked liquid deuterium to 75 <span class="hlt">GPa</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Knudson, M D; Hanson, D L; Bailey, J E; Hall, C A; Asay, J R</p> <p>2003-01-24</p> <p>A novel approach was developed to probe density compression of liquid deuterium (L-D2) along the principal Hugoniot. Relative transit times of shock waves reverberating within the sample are shown to be sensitive to the compression due to the first shock. This technique has proven to be more sensitive than the conventional method of inferring density from the shock and mass velocity, at least in this high-pressure regime. Results in the range of 22-75 <span class="hlt">GPa</span> indicate an approximately fourfold density compression, and provide data to differentiate between proposed theories for hydrogen and its isotopes.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860001084','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860001084"><span>Measurement of the Density of Base Fluids at Pressures 0.422 to 2.20 <span class="hlt">Gpa</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hamrock, B. J.; Jacobson, B. O.; Bergstroem, S. I.</p> <p>1985-01-01</p> <p>The influence of pressure on the density of six base fluids is experimentally studied for a range of pressures from 0.422 to 2.20 <span class="hlt">GPa</span>. An important parameter used to describe the results is the change in relative volume with change in pressure dv sub r/dp. For pressures less than the solidification pressure (p ps) a small change in pressure results in a large change in dv sub r/ps. For pressures greater than the solidification pressure (p ps) there is no change in dv sub r/dp with changing pressure. The solidification pressures of the base fluids varies considerably, as do the slopes that the experimental data assumes for p ps. A new formula is developed that describes the effect of pressure on density in terms of four constants. These constants vary for the different base fluids tested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1340256','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1340256"><span>Measurements of the sound velocity of shock-compressed liquid silica to 1100 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>McCoy, Chad August; Gregor, Michelle C.; Polsin, Danae N.</p> <p></p> <p>The sound velocity in a shocked material provides information about its off-Hugoniot behavior of a material at high pressures. This information can be used to extend the knowledge gained in Hugoniot experiments and to model the re-shock and release behavior. Silica is one of the most important materials for equation of state studies because of its prevalence in the earth’s interior and the well-defined properties of α-quartz. This paper presents sound velocity measurements of amorphous fused silica over the range 200 to 1100 <span class="hlt">GPa</span> using laser-driven shocks and an α- quartz standard. These measurements demonstrate the technique proposed by Fratanduonomore » et al [J. Appl. Phys 116, 033517 (2014)] to determine the sound velocity from the arrival of acoustic perturbations. The results compare favorably to the SESAME 7386 equation-of-state table. The Grüneisen parameter was calculated from the sound velocity data and found to be Γ=0.66 ± 0.05 at densities above 6 g/cm 3, an increase in precision by a factor of two over previous measurements.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1340256-measurements-sound-velocity-shock-compressed-liquid-silica-gpa','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1340256-measurements-sound-velocity-shock-compressed-liquid-silica-gpa"><span>Measurements of the sound velocity of shock-compressed liquid silica to 1100 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>McCoy, Chad August; Gregor, Michelle C.; Polsin, Danae N.; ...</p> <p>2016-12-19</p> <p>The sound velocity in a shocked material provides information about its off-Hugoniot behavior of a material at high pressures. This information can be used to extend the knowledge gained in Hugoniot experiments and to model the re-shock and release behavior. Silica is one of the most important materials for equation of state studies because of its prevalence in the earth’s interior and the well-defined properties of α-quartz. This paper presents sound velocity measurements of amorphous fused silica over the range 200 to 1100 <span class="hlt">GPa</span> using laser-driven shocks and an α- quartz standard. These measurements demonstrate the technique proposed by Fratanduonomore » et al [J. Appl. Phys 116, 033517 (2014)] to determine the sound velocity from the arrival of acoustic perturbations. The results compare favorably to the SESAME 7386 equation-of-state table. The Grüneisen parameter was calculated from the sound velocity data and found to be Γ=0.66 ± 0.05 at densities above 6 g/cm 3, an increase in precision by a factor of two over previous measurements.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16477335','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16477335"><span>Thin-plate spline <span class="hlt">analysis</span> of the effects of face mask treatment in children with maxillary retrognathism.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chang, Jenny Zwei-Chieng; Liu, Pao-Hsin; Chen, Yi-Jane; Yao, Jane Chung-Chen; Chang, Hong-Po; Chang, Chih-Han; Chang, Frank Hsin-Fu</p> <p>2006-02-01</p> <p>Face mask therapy is indicated for growing patients who suffer from maxillary retrognathia. Most previous studies used conventional cephalometric <span class="hlt">analysis</span> to evaluate the effects of face mask treatment. Cephalometric <span class="hlt">analysis</span> has been shown to be insufficient for complex craniofacial configurations. The purpose of this study was to investigate changes in the craniofacial structure of children with maxillary retrognathism following face mask treatment by means of thin-plate spline <span class="hlt">analysis</span>. Thirty children with skeletal Class III malocclusions who had been treated with face masks were compared with a group of 30 untreated gender-matched, age-matched, observation period-matched, and craniofacial configuration-matched subjects. Average geometries, scaled to an equivalent size, were generated by means of <span class="hlt">Procrustes</span> <span class="hlt">analysis</span>. Thin-plate spline <span class="hlt">analysis</span> was then performed for localization of the shape changes. Face mask treatment induced a forward displacement of the maxilla, a counterclockwise rotation of the palatal plane, a horizontal compression of the anterior border of the symphysis and the condylar region, and a downward deformation of the menton. The cranial base exhibited a counterclockwise deformation as a whole. We conclude that thin-plate spline <span class="hlt">analysis</span> is a valuable supplement to conventional cephalometric <span class="hlt">analysis</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1259836','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1259836"><span>Probing off-Hugoniot states in Ta, Cu, and Al to 1000 <span class="hlt">GPa</span> compression with magnetically driven liner implosions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Lemke, R. W.; Dolan, D. H.; Dalton, D. G.</p> <p></p> <p>We report on a new technique for obtaining off-Hugoniot pressure vs. density data for solid metals compressed to extreme pressure by a magnetically driven liner implosion on the Z-machine (Z) at Sandia National Laboratories. In our experiments, the liner comprises inner and outer metal tubes. The inner tube is composed of a sample material (e.g., Ta and Cu) whose compressed state is to be inferred. The outer tube is composed of Al and serves as the current carrying cathode. Another aluminum liner at much larger radius serves as the anode. A shaped current pulse quasi-isentropically compresses the sample as itmore » implodes. The iterative method used to infer pressure vs. density requires two velocity measurements. Photonic Doppler velocimetry probes measure the implosion velocity of the free (inner) surface of the sample material and the explosion velocity of the anode free (outer) surface. These two velocities are used in conjunction with magnetohydrodynamic simulation and mathematical optimization to obtain the current driving the liner implosion, and to infer pressure and density in the sample through maximum compression. This new equation of state calibration technique is illustrated using a simulated experiment with a Cu sample. Monte Carlo uncertainty quantification of synthetic data establishes convergence criteria for experiments. Results are presented from experiments with Al/Ta, Al/Cu, and Al liners. Symmetric liner implosion with quasi-isentropic compression to peak pressure ~1000 <span class="hlt">GPa</span> is achieved in all cases. Lastly, these experiments exhibit unexpectedly softer behavior above 200 <span class="hlt">GPa</span>, which we conjecture is related to differences in the actual and modeled properties of aluminum.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1259836-probing-off-hugoniot-states-ta-cu-al-gpa-compression-magnetically-driven-liner-implosions','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1259836-probing-off-hugoniot-states-ta-cu-al-gpa-compression-magnetically-driven-liner-implosions"><span>Probing off-Hugoniot states in Ta, Cu, and Al to 1000 <span class="hlt">GPa</span> compression with magnetically driven liner implosions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Lemke, R. W.; Dolan, D. H.; Dalton, D. G.; ...</p> <p>2016-01-07</p> <p>We report on a new technique for obtaining off-Hugoniot pressure vs. density data for solid metals compressed to extreme pressure by a magnetically driven liner implosion on the Z-machine (Z) at Sandia National Laboratories. In our experiments, the liner comprises inner and outer metal tubes. The inner tube is composed of a sample material (e.g., Ta and Cu) whose compressed state is to be inferred. The outer tube is composed of Al and serves as the current carrying cathode. Another aluminum liner at much larger radius serves as the anode. A shaped current pulse quasi-isentropically compresses the sample as itmore » implodes. The iterative method used to infer pressure vs. density requires two velocity measurements. Photonic Doppler velocimetry probes measure the implosion velocity of the free (inner) surface of the sample material and the explosion velocity of the anode free (outer) surface. These two velocities are used in conjunction with magnetohydrodynamic simulation and mathematical optimization to obtain the current driving the liner implosion, and to infer pressure and density in the sample through maximum compression. This new equation of state calibration technique is illustrated using a simulated experiment with a Cu sample. Monte Carlo uncertainty quantification of synthetic data establishes convergence criteria for experiments. Results are presented from experiments with Al/Ta, Al/Cu, and Al liners. Symmetric liner implosion with quasi-isentropic compression to peak pressure ~1000 <span class="hlt">GPa</span> is achieved in all cases. Lastly, these experiments exhibit unexpectedly softer behavior above 200 <span class="hlt">GPa</span>, which we conjecture is related to differences in the actual and modeled properties of aluminum.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29716198','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29716198"><span>In situ Raman and X-ray diffraction studies on the high pressure and temperature stability of methane hydrate up to 55 <span class="hlt">GPa</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kadobayashi, Hirokazu; Hirai, Hisako; Ohfuji, Hiroaki; Ohtake, Michika; Yamamoto, Yoshitaka</p> <p>2018-04-28</p> <p>High-temperature and high-pressure experiments were performed under 2-55 <span class="hlt">GPa</span> and 298-653 K using in situ Raman spectroscopy and X-ray diffraction combined with externally heated diamond anvil cells to investigate the stability of methane hydrate. Prior to in situ experiments, the typical C-H vibration modes of methane hydrate and their pressure dependence were measured at room temperature using Raman spectroscopy to make a clear discrimination between methane hydrate and solid methane which forms through the decomposition of methane hydrate at high temperature. The sequential in situ Raman spectroscopy and X-ray diffraction revealed that methane hydrate survives up to 633 K and 40.3 <span class="hlt">GPa</span> and then decomposes into solid methane and ice VII above the conditions. The decomposition curve of methane hydrate estimated by the present experiments is >200 K lower than the melting curves of solid methane and ice VII, and moderately increases with increasing pressure. Our result suggests that although methane hydrate may be an important candidate for major constituents of cool exoplanets and other icy bodies, it is unlikely to be present in the ice mantle of Neptune and Uranus, where the temperature is expected to be far beyond the decomposition temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JChPh.148p4503K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JChPh.148p4503K"><span>In situ Raman and X-ray diffraction studies on the high pressure and temperature stability of methane hydrate up to 55 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kadobayashi, Hirokazu; Hirai, Hisako; Ohfuji, Hiroaki; Ohtake, Michika; Yamamoto, Yoshitaka</p> <p>2018-04-01</p> <p>High-temperature and high-pressure experiments were performed under 2-55 <span class="hlt">GPa</span> and 298-653 K using in situ Raman spectroscopy and X-ray diffraction combined with externally heated diamond anvil cells to investigate the stability of methane hydrate. Prior to in situ experiments, the typical C-H vibration modes of methane hydrate and their pressure dependence were measured at room temperature using Raman spectroscopy to make a clear discrimination between methane hydrate and solid methane which forms through the decomposition of methane hydrate at high temperature. The sequential in situ Raman spectroscopy and X-ray diffraction revealed that methane hydrate survives up to 633 K and 40.3 <span class="hlt">GPa</span> and then decomposes into solid methane and ice VII above the conditions. The decomposition curve of methane hydrate estimated by the present experiments is >200 K lower than the melting curves of solid methane and ice VII, and moderately increases with increasing pressure. Our result suggests that although methane hydrate may be an important candidate for major constituents of cool exoplanets and other icy bodies, it is unlikely to be present in the ice mantle of Neptune and Uranus, where the temperature is expected to be far beyond the decomposition temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeCoA.124..328D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeCoA.124..328D"><span>CO2 solubility and speciation in rhyolitic sediment partial melts at 1.5-3.0 <span class="hlt">GPa</span> - Implications for carbon flux in subduction zones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duncan, Megan S.; Dasgupta, Rajdeep</p> <p>2014-01-01</p> <p>Partial melts of subducting sediments are thought to be critical agents in carrying trace elements and water to arc basalt source regions. Sediment partial melts may also act as a carrier of CO2. However, the CO2 carrying capacity of natural rhyolitic melts that derive from partial fusion of downgoing sediment at sub-arc depths remains unconstrained. We conducted CO2-solubility experiments on a rhyolitic composition similar to average, low-degree experimental partial melt of pelitic sediments between 1.5 and 3.0 <span class="hlt">GPa</span> at 1300 °C and containing variable water content. Concentrations of water and carbon dioxide were measured using FTIR. Molecular CO2(CO2mol.) and carbonate anions (CO32-) both appear as equilibrium species in our experimental melts. Estimated total CO2 concentrations (CO2mol.+CO32-) increased with increasing pressure and water content. At 3.0 <span class="hlt">GPa</span>, the bulk CO2 solubility are in the range of ∼1-2.5 wt.%, for melts with H2O contents between 0.5 and 3.5 wt.%. For melts with low H2O content (∼0.5 wt.%), CO2mol. is the dominant carbon species, while in more H2O-rich melts CO32- becomes dominant. The experimentally determined, speciation-specific CO2 solubilities yielded thermodynamic parameters that control dissolution of CO2 vapor both as CO2mol. and as CO32- in silicate melt for each of our compositions with different water content; CO2vapor ↔CO2melt :lnK0=-15 to -18, ΔV0 = 29 to 14 cm3 mol-1 and CO2vapor +Omelt →CO32-melt :lnK0=-20 to -14, ΔV0 = 9 to 27 cm3 mol-1, with ΔV0 of reaction being larger for formation of CO2mol. in water-poor melts and for formation of CO32- in water-rich melts. Our bulk CO2 solubility data, [CO2] (in wt.%) can be fitted as a function of pressure, P (in <span class="hlt">GPa</span>) and melt water content, [H2O] (in wt.%) with the following function: [CO2](wt.%)=(-0.01108[H2O]+0.03969)P2+(0.10328[H2O]+0.41165)P. This parameterization suggests that over the range of sub-arc depths of 72-173 km, water-rich sediment partial melt may carry as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MMI...tmp...56C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MMI...tmp...56C"><span>Fabrication of Hadfield-Cored Multi-layer Steel Sheet by Roll-Bonding with 1.8-<span class="hlt">GPa</span>-Strength-Grade Hot-Press-Forming Steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chin, Kwang-Geun; Kang, Chung-Yun; Park, Jaeyeong; Lee, Sunghak</p> <p>2018-03-01</p> <p>An austenitic Hadfield steel was roll-bonded with a 1.8-<span class="hlt">GPa</span>-strength-grade martensitic hot-press-forming (HPF) steel to fabricate a multi-layer steel (MLS) sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2%C) to HPF (0.35%C) layers, and could be regarded as kinds of very thin multi-layers of 35 μm in thickness. The tensile test and fractographic data indicated that the MLS sheet was fractured abruptly within the elastic range by the intergranular fracture occurred in the carburized layer. This was because C was mainly segregated at prior austenite grain boundaries in the carburized layer, which weakened grain boundaries to induce the intergranular fracture. In order to solve the intergranular facture problem, the MLS sheet was tempered at 200 °C. The stress-strain curve of the tempered MLS sheet lay between those of the HPF and Hadfield sheets, and a rule of mixtures was roughly satisfied. Tensile properties of the MLS sheet were dramatically improved after the tempering, and the intergranular fracture was erased completely. In particular, the yield strength up to 1073 MPa along with the high strain hardening and excellent ductility of 32.4% were outstanding because the yield strength over 1 <span class="hlt">GPa</span> was hardly achieved in conventional austenitic steels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1235280-adiabatic-release-measurements-aluminum-between-gpa-characterization-aluminum-shock-standard-multimegabar-regime','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1235280-adiabatic-release-measurements-aluminum-between-gpa-characterization-aluminum-shock-standard-multimegabar-regime"><span>Adiabatic release measurements in aluminum between 400 and 1200 <span class="hlt">GPa</span>: Characterization of aluminum as a shock standard in the multimegabar regime</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Knudson, Marcus D.; Desjarlais, Michael P.; Pribram-Jones, Aurora</p> <p>2015-06-15</p> <p>Aluminum has been used prolifically as an impedance matching standard in the multimegabar regime (1 Mbar = 100 <span class="hlt">GPa</span>), particularly in nuclear driven, early laser driven, and early magnetically driven flyer plate experiments. The accuracy of these impedance matching measurements depends upon the knowledge of both the Hugoniot and release or reshock response of aluminum. Here, we present the results of several adiabatic release measurements of aluminum from ~400–1200 <span class="hlt">GPa</span> states along the principal Hugoniot using full density polymethylpentene (commonly known as TPX), and both ~190 and ~110 mg/cc silica aerogel standards. Additionally, these data were analyzed within the frameworkmore » of a simple, analytical model that was motivated by a first-principles molecular dynamics investigation into the release response of aluminum, as well as by a survey of the release response determined from several tabular equations of state for aluminum. Combined, this theoretical and experimental study provides a method to perform impedance matching calculations without the need to appeal to any tabular equation of state for aluminum. Furthermore, as an analytical model, this method allows for propagation of all uncertainty, including the random measurement uncertainties and the systematic uncertainties of the Hugoniot and release response of aluminum. This work establishes aluminum for use as a high-precision standard for impedance matching in the multimegabar regime.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MMI....24..489C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MMI....24..489C"><span>Fabrication of Hadfield-Cored Multi-layer Steel Sheet by Roll-Bonding with 1.8-<span class="hlt">GPa</span>-Strength-Grade Hot-Press-Forming Steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chin, Kwang-Geun; Kang, Chung-Yun; Park, Jaeyeong; Lee, Sunghak</p> <p>2018-05-01</p> <p>An austenitic Hadfield steel was roll-bonded with a 1.8-<span class="hlt">GPa</span>-strength-grade martensitic hot-press-forming (HPF) steel to fabricate a multi-layer steel (MLS) sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2%C) to HPF (0.35%C) layers, and could be regarded as kinds of very thin multi-layers of 35 μm in thickness. The tensile test and fractographic data indicated that the MLS sheet was fractured abruptly within the elastic range by the intergranular fracture occurred in the carburized layer. This was because C was mainly segregated at prior austenite grain boundaries in the carburized layer, which weakened grain boundaries to induce the intergranular fracture. In order to solve the intergranular facture problem, the MLS sheet was tempered at 200 °C. The stress-strain curve of the tempered MLS sheet lay between those of the HPF and Hadfield sheets, and a rule of mixtures was roughly satisfied. Tensile properties of the MLS sheet were dramatically improved after the tempering, and the intergranular fracture was erased completely. In particular, the yield strength up to 1073 MPa along with the high strain hardening and excellent ductility of 32.4% were outstanding because the yield strength over 1 <span class="hlt">GPa</span> was hardly achieved in conventional austenitic steels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMMR31B0440B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMMR31B0440B"><span>Experimental Thermodynamics of [Na-Mg-Cl-SO4] Aqueous Solutions at <span class="hlt">GPa</span> Pressure With Application to Icy Worlds.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, J. M.; Bollengier, O.; Vance, S.</p> <p>2017-12-01</p> <p>Water competes with silicates as the main constituent of solid bodies in the outer solar system. Ganymede and Titan, the Mercury-sized satellites of Jupiter and Saturn, are made up half of water present as massive hydrospheres where pressure can reach up to 1.5 <span class="hlt">GPa</span>. Geophysical data and planetary models unequivocally support the existence of global aqueous oceans trapped in these hydrospheres. However, the extent of these oceans and their role in the processes governing the internal structure of these moons remain unresolved. At issue is the poor to non-existent characterization, at the relevant pressures, of the properties of the aqueous fluids of significance to the outer solar system (with notably the Na-Mg-Cl-SO4 salts found in primitive chondrites), forcing current models to rely on pure water only. Our team at the University of Washington has developed an experimental apparatus to acquire the speed of sound of aqueous solutions in the 0 - 0.7 <span class="hlt">GPa</span> and 250 - 350 K pressure and temperature ranges covering most of the conditions of existence of these extra-terrestrial oceans. Speeds of sound measured over a grid of pressures and temperatures allow calculation of the thermodynamic quantities (G, ρ, μ...) required for planetary science. Early <span class="hlt">analysis</span> of pure water samples indicates our experimental results are on par with (at lower pressures), or better than, the IAPWS water laboratory standard, with sound speeds determined to 0.02% over our entire pressure range. For the first time at the high pressures of interest for large icy moons, we achieved the exploration of H2O-NaCl, H2O-MgSO4, H2O-Na2SO4 and H2O-MgCl2 solutions, from dilute concentrations to saturation. We are now in the process of acquiring the first data for H2O-NaCl-MgSO4 mixtures. We will briefly present our experimental setup and the underlying sound speed theory, and will then compare our results for the four endmembers, with an emphasis on their different association behavior under pressure as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22314383-refractive-index-cut-sapphire-under-shock-pressure-range','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22314383-refractive-index-cut-sapphire-under-shock-pressure-range"><span>Refractive index of r-cut sapphire under shock pressure range 5 to 65 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Cao, Xiuxia; Li, Jiabo; Li, Jun</p> <p>2014-09-07</p> <p>High-pressure refractive index of optical window materials not only can provide information on electronic polarizability and band-gap structure, but also is important for velocity correction in particle-velocity measurement with laser interferometers. In this work, the refractive index of r-cut sapphire window at 1550 nm wavelength was measured under shock pressures of 5–65 <span class="hlt">GPa</span>. The refractive index (n) decreases linearly with increasing shock density (ρ) for shock stress above the Hugoniot elastic limit (HEL): n = 2.0485 (± 0.0197) − 0.0729 (± 0.0043)ρ, while n remains nearly a constant for elastic shocks. This behavior is attributed to the transition from elastic (below HEL) to heterogeneous plastic deformationmore » (above HEL). Based on the obtained refractive index-density relationship, polarizability of the shocked sapphire was also obtained.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JNR....14..857G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JNR....14..857G"><span>Factors influencing societal response of nanotechnology: an expert stakeholder <span class="hlt">analysis</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gupta, Nidhi; Fischer, Arnout R. H.; van der Lans, Ivo A.; Frewer, Lynn J.</p> <p>2012-05-01</p> <p>Nanotechnology can be described as an emerging technology and, as has been the case with other emerging technologies such as genetic modification, different socio-psychological factors will potentially influence societal responses to its development and application. These factors will play an important role in how nanotechnology is developed and commercialised. This article aims to identify expert opinion on factors influencing societal response to applications of nanotechnology. Structured interviews with experts on nanotechnology from North West Europe were conducted using repertory grid methodology in conjunction with generalized <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> to examine the psychological constructs underlying societal uptake of 15 key applications of nanotechnology drawn from different areas (e.g. medicine, agriculture and environment, chemical, food, military, sports, and cosmetics). Based on expert judgement, the main factors influencing societal response to different applications of nanotechnology will be the extent to which applications are perceived to be beneficial, useful, and necessary, and how 'real' and physically close to the end-user these applications are perceived to be by the public.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999SPIE.3516..234N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999SPIE.3516..234N"><span>Precise optical observation of 0.5-<span class="hlt">GPa</span> shock waves in condensed materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nagayama, Kunihito; Mori, Yasuhito</p> <p>1999-06-01</p> <p>Precision optical observation method was developed to study impact-generated high-pressure shock waves in condensed materials. The present method makes it possible to sensitively detect the shock waves of the relatively low shock stress around 0.5 <span class="hlt">GPa</span>. The principle of the present method is based on the use of total internal reflection by triangular prisms placed on the free surface of a target assembly. When a plane shock wave arrives at the free surface, the light reflected from the prisms extinguishes instantaneously. The reason is that the total internal reflection changes to the reflection depending on micron roughness of the free surface after the shock arrival. The shock arrival at the bottom face of the prisms can be detected here by two kinds of methods, i.e., a photographic method and a gauge method. The photographic method is an inclined prism method of using a high-speed streak camera. The shock velocity and the shock tilt angle can be estimated accurately from an obtained streak photograph. While in the gauge method, an in-material PVDF stress gauge is combined with an optical prism-pin. The PVDF gauge records electrically the stress profile behind the shockwave front, and the Hugoniot data can be precisely measured by combining the prism pin with the PVDF gauge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26094205','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26094205"><span>Artefacts in geometric phase <span class="hlt">analysis</span> of compound materials.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Peters, Jonathan J P; Beanland, Richard; Alexe, Marin; Cockburn, John W; Revin, Dmitry G; Zhang, Shiyong Y; Sanchez, Ana M</p> <p>2015-10-01</p> <p>The geometric phase <span class="hlt">analysis</span> (<span class="hlt">GPA</span>) algorithm is known as a robust and straightforward technique that can be used to measure lattice strains in high resolution transmission electron microscope (TEM) images. It is also attractive for <span class="hlt">analysis</span> of aberration-corrected scanning TEM (ac-STEM) images that resolve every atom column, since it uses Fourier transforms and does not require real-space peak detection and assignment to appropriate sublattices. Here it is demonstrated that, in ac-STEM images of compound materials with compositionally distinct atom columns, an additional geometric phase is present in the Fourier transform. If the structure changes from one area to another in the image (e.g. across an interface), the change in this additional phase will appear as a strain in conventional <span class="hlt">GPA</span>, even if there is no lattice strain. Strategies to avoid this pitfall are outlined. Copyright © 2015 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.477L.101R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.477L.101R"><span>Gradient pattern <span class="hlt">analysis</span> applied to galaxy morphology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosa, R. R.; de Carvalho, R. R.; Sautter, R. A.; Barchi, P. H.; Stalder, D. H.; Moura, T. C.; Rembold, S. B.; Morell, D. R. F.; Ferreira, N. C.</p> <p>2018-06-01</p> <p>Gradient pattern <span class="hlt">analysis</span> (<span class="hlt">GPA</span>) is a well-established technique for measuring gradient bilateral asymmetries of a square numerical lattice. This paper introduces an improved version of <span class="hlt">GPA</span> designed for galaxy morphometry. We show the performance of the new method on a selected sample of 54 896 objects from the SDSS-DR7 in common with Galaxy Zoo 1 catalogue. The results suggest that the second gradient moment, G2, has the potential to dramatically improve over more conventional morphometric parameters. It separates early- from late-type galaxies better (˜ 90 per cent) than the CAS system (C˜ 79 per cent, A˜ 50 per cent, S˜ 43 per cent) and a benchmark test shows that it is applicable to hundreds of thousands of galaxies using typical processing systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.tmpL..54R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.tmpL..54R"><span>Gradient Pattern <span class="hlt">Analysis</span> Applied to Galaxy Morphology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosa, R. R.; de Carvalho, R. R.; Sautter, R. A.; Barchi, P. H.; Stalder, D. H.; Moura, T. C.; Rembold, S. B.; Morell, D. R. F.; Ferreira, N. C.</p> <p>2018-04-01</p> <p>Gradient pattern <span class="hlt">analysis</span> (<span class="hlt">GPA</span>) is a well-established technique for measuring gradient bilateral asymmetries of a square numerical lattice. This paper introduces an improved version of <span class="hlt">GPA</span> designed for galaxy morphometry. We show the performance of the new method on a selected sample of 54,896 objects from the SDSS-DR7 in common with Galaxy Zoo 1 catalog. The results suggest that the second gradient moment, G2, has the potential to dramatically improve over more conventional morphometric parameters. It separates early from late type galaxies better (˜90%) than the CAS system (C ˜ 79%, A ˜ 50%, S ˜ 43%) and a benchmark test shows that it is applicable to hundreds of thousands of galaxies using typical processing systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMMR41A2092S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMMR41A2092S"><span>Sound velocity measurements of dhcp-FeHx up to 70 <span class="hlt">GPa</span> using inelastic X-ray scattering: Implications for the abundance of hydrogen in the Earth's core</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shibazaki, Y.; Ohtani, E.; Fukui, H.; Sakai, T.; Kamada, S.; Baron, A. Q.; Nishitani, N.; Hirao, N.; Takemura, K.</p> <p>2011-12-01</p> <p>The Earth's interior has been directly investigated by seismic wave propagation and normal mode oscillation. In particular, the distributions of density and sound velocity are available to study the Earth's core (e.g. PREM). The inner core, which is solid state, is approximately 3 % less dense than pure iron (a core density deficit), and it is considered that the core consists of iron and light elements, such as hydrogen, carbon, oxygen, silicon, and sulfur. In this work, in order to constrain the abundance of hydrogen in the Earth's core by matching the density and sound velocity of FeHx to those of PREM, we determined the compressional sound velocity of iron hydride at high pressure using inelastic X-ray scattering (IXS). The IXS experiments and in situ X-ray diffraction (XRD) experiments were conducted up to 70 <span class="hlt">GPa</span> and room temperature. High-pressure conditions were generated using a symmetric diamond anvil cell (DAC) with tungsten gaskets. Hydrogen initially pressurized to 0.18 <span class="hlt">GPa</span> was loaded to the sample chamber. The IXS experiments were performed at BL35XU of the SPring-8 facility in Japan. The XRD experiments at high pressure were carried out by the angle dispersive method at BL10XU of the SPring-8 facility in Japan. The each XRD pattern of FeHx was collected after each IXS measurement in order to obtain directly the density of FeHx. Over the range of pressure studied, the diffraction lines of double-hexagonal close-packed (dhcp)-FeHx were observed and there were no diffraction lines of iron. We show that FeHx follows Birch's law for Vp above 37 <span class="hlt">GPa</span>, namely a linear dependence between velocity and density. The estimated Vp, extrapolated to core conditions, is compared with PREM. Our results provide that the Earth's inner core could contain about 0.2 wt% hydrogen.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22494876-probing-off-hugoniot-states-ta-cu-al-compression-magnetically-driven-liner-implosions','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22494876-probing-off-hugoniot-states-ta-cu-al-compression-magnetically-driven-liner-implosions"><span>Probing off-Hugoniot states in Ta, Cu, and Al to 1000 <span class="hlt">GPa</span> compression with magnetically driven liner implosions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Lemke, R. W., E-mail: rwlemke@sandia.gov; Dolan, D. H.; Dalton, D. G.</p> <p></p> <p>We report on a new technique for obtaining off-Hugoniot pressure vs. density data for solid metals compressed to extreme pressure by a magnetically driven liner implosion on the Z-machine (Z) at Sandia National Laboratories. In our experiments, the liner comprises inner and outer metal tubes. The inner tube is composed of a sample material (e.g., Ta and Cu) whose compressed state is to be inferred. The outer tube is composed of Al and serves as the current carrying cathode. Another aluminum liner at much larger radius serves as the anode. A shaped current pulse quasi-isentropically compresses the sample as itmore » implodes. The iterative method used to infer pressure vs. density requires two velocity measurements. Photonic Doppler velocimetry probes measure the implosion velocity of the free (inner) surface of the sample material and the explosion velocity of the anode free (outer) surface. These two velocities are used in conjunction with magnetohydrodynamic simulation and mathematical optimization to obtain the current driving the liner implosion, and to infer pressure and density in the sample through maximum compression. This new equation of state calibration technique is illustrated using a simulated experiment with a Cu sample. Monte Carlo uncertainty quantification of synthetic data establishes convergence criteria for experiments. Results are presented from experiments with Al/Ta, Al/Cu, and Al liners. Symmetric liner implosion with quasi-isentropic compression to peak pressure ∼1000 <span class="hlt">GPa</span> is achieved in all cases. These experiments exhibit unexpectedly softer behavior above 200 <span class="hlt">GPa</span>, which we conjecture is related to differences in the actual and modeled properties of aluminum.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011CoMP..161..743T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011CoMP..161..743T"><span>Melting phase relation of nominally anhydrous, carbonated pelitic-eclogite at 2.5-3.0 <span class="hlt">GPa</span> and deep cycling of sedimentary carbon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsuno, Kyusei; Dasgupta, Rajdeep</p> <p>2011-05-01</p> <p>We have experimentally investigated melting phase relation of a nominally anhydrous, carbonated pelitic eclogite (HPLC1) at 2.5 and 3.0 <span class="hlt">GPa</span> at 900-1,350°C in order to constrain the cycling of sedimentary carbon in subduction zones. The starting composition HPLC1 (with 5 wt% bulk CO2) is a model composition, on a water-free basis, and is aimed to represent a mixture of 10 wt% pelagic carbonate unit and 90 wt% hemipelagic mud unit that enter the Central American trench. Sub-solidus assemblage comprises clinopyroxene + garnet + K-feldspar + quartz/coesite + rutile + calcio-ankerite/ankeritess. Solidus temperature is at 900-950°C at 2.5 <span class="hlt">GPa</span> and at 900-1,000°C at 3.0 <span class="hlt">GPa</span>, and the near-solidus melt is K-rich granitic. Crystalline carbonates persist only 50-100°C above the solidus and at temperatures above carbonate breakdown, carbon exists in the form of dissolved CO2 in silica-rich melts and as a vapor phase. The rhyodacitic to dacitic partial melt evolves from a K-rich composition at near-solidus condition to K-poor, and Na- and Ca-rich composition with increasing temperature. The low breakdown temperatures of crystalline carbonate in our study compared to those of recent studies on carbonated basaltic eclogite and peridotite owes to Fe-enrichment of carbonates in pelitic lithologies. However, the conditions of carbonate release in our study still remain higher than the modern depth-temperature trajectories of slab-mantle interface at sub-arc depths, suggesting that the release of sedimentary carbonates is unlikely in modern subduction zones. One possible scenario of carbonate release in modern subduction zones is the detachment and advection of sedimentary piles to hotter mantle wedge and consequent dissolution of carbonate in rhyodacitic partial melt. In the Paleo-NeoProterozoic Earth, on the other hand, the hotter slab-surface temperatures at subduction zones likely caused efficient liberation of carbon from subducting sedimentary carbonates. Deeply subducted</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018HPR....38...99L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018HPR....38...99L"><span>Decreasing electrical resistivity of silver along the melting boundary up to 5 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Littleton, Joshua A. H.; Secco, Richard A.; Yong, Wenjun</p> <p>2018-04-01</p> <p>The electrical resistivity of Ag was experimentally measured at high pressures up to 5 <span class="hlt">GPa</span> and at temperatures up to ∼300 K above melting. The resistivity decreased as a function of pressure and increased as a function of temperature as expected and is in very good agreement with 1 atm data. Observed melting temperatures at high pressures also agree well with previous experimental and theoretical studies. The main finding of this study is that resistivity of Ag decreases along the pressure- and temperature-dependent melting boundary, in conflict with prediction of resistivity invariance. This result is discussed in terms of the dominant contribution of the increasing energy separation between the Fermi level and 4d-band as a function of pressure. Calculated from the resistivity using the Wiedemann-Franz law, the electronic thermal conductivity increased as a function of pressure and decreased as a function of temperature as expected. The decrease in the high pressure thermal conductivity in the liquid phase as a function of temperature contrasts with the behavior of the 1 atm data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22410200-sound-velocity-tantalum-under-shock-compression-range','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22410200-sound-velocity-tantalum-under-shock-compression-range"><span>Sound velocity of tantalum under shock compression in the 18–142 <span class="hlt">GPa</span> range</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Xi, Feng, E-mail: xifeng@caep.cn; Jin, Ke; Cai, Lingcang, E-mail: cai-lingcang@aliyun.com</p> <p>2015-05-14</p> <p>Dynamic compression experiments of tantalum (Ta) within a shock pressure range from 18–142 <span class="hlt">GPa</span> were conducted driven by explosive, a two-stage light gas gun, and a powder gun, respectively. The time-resolved Ta/LiF (lithium fluoride) interface velocity profiles were recorded with a displacement interferometer system for any reflector. Sound velocities of Ta were obtained from the peak state time duration measurements with the step-sample technique and the direct-reverse impact technique. The uncertainty of measured sound velocities were analyzed carefully, which suggests that the symmetrical impact method with step-samples is more accurate for sound velocity measurement, and the most important parameter in thismore » type experiment is the accurate sample/window particle velocity profile, especially the accurate peak state time duration. From these carefully analyzed sound velocity data, no evidence of a phase transition was found up to the shock melting pressure of Ta.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14578879','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14578879"><span>Congruent melting of gallium nitride at 6 <span class="hlt">GPa</span> and its application to single-crystal growth.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Utsumi, Wataru; Saitoh, Hiroyuki; Kaneko, Hiroshi; Watanuki, Tetsu; Aoki, Katsutoshi; Shimomura, Osamu</p> <p>2003-11-01</p> <p>The synthesis of large single crystals of GaN (gallium nitride) is a matter of great importance in optoelectronic devices for blue-light-emitting diodes and lasers. Although high-quality bulk single crystals of GaN suitable for substrates are desired, the standard method of cooling its stoichiometric melt has been unsuccessful for GaN because it decomposes into Ga and N(2) at high temperatures before its melting point. Here we report that applying high pressure completely prevents the decomposition and allows the stoichiometric melting of GaN. At pressures above 6.0 <span class="hlt">GPa</span>, congruent melting of GaN occurred at about 2,220 degrees C, and decreasing the temperature allowed the GaN melt to crystallize to the original structure, which was confirmed by in situ X-ray diffraction. Single crystals of GaN were formed by cooling the melt slowly under high pressures and were recovered at ambient conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V33D2798F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V33D2798F"><span>Metal-silicate partitioning of Co, Ni, V, Cr, Si, and O up to 100 <span class="hlt">GPa</span> and 5500 K: Implications for core formation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fischer, R. A.; Campbell, A. J.; Frost, D. J.; Harries, D.; Langenhorst, F.; Miyajima, N.; Pollok, K.; Rubie, D. C.</p> <p>2013-12-01</p> <p>During core formation, metal and silicate of accreted bodies equilibrated with the proto-Earth in a series of partitioning reactions, characterized by average (or time-intregrated) partition coefficients that can be calculated assuming a bulk Earth that is chondritic in nonvolatile elements [e.g. 1]. Comparisons to experimentally-measured partition coefficients allow constraints on the time-integrated conditions of core-mantle equilibration [e.g. 2-7], providing valuable input into more complex chemical models of Earth's evolution [8]. Partitioning has been studied extensively in the multi-anvil press [e.g. 3, 7], but very few studies extend to pressures above ~25 <span class="hlt">GPa</span> [e.g. 2, 5-6]. In this study, we measure the metal-silicate partitioning of Co, Ni, V, Cr, Si, and O at higher pressures and temperatures. Thin foils of Fe-rich alloy doped with trace elements were loaded in a diamond anvil cell between layers of (Mg,Fe)2SiO4. Samples were laser-heated to melt the metal and silicate. After decompression, samples were cut parallel to the compression axis into sections ~100 nm thick with a focused ion beam (FIB). Chemical analyses of all elements except oxygen in the coexisting metal, silicate, and oxide were performed using energy dispersive X-ray spectroscopy (EDXS) in a transmission electron microscope (TEM). Later, samples were further thinned by FIB to ~60 nm and analyzed by electron energy loss spectroscopy (EELS) in a TEM to determine the Fe/O ratio of the metal. <span class="hlt">Analysis</span> was performed on a suite of six experiments from pressures of 25, 31, 43, 57, 58, and 100 <span class="hlt">GPa</span> and temperatures above the silicate liquidus, up to 5500 K. Our results are generally consistent with the recent findings of [5-6], although our log(KD) values for cobalt are ~0.1-0.2 log units lower. Some of our experiments contain carbon in the metal which may affect the partitioning of some elements. The metal in the experiment from 100 <span class="hlt">GPa</span> and 5500 K contains 9 wt% silicon and an estimated 11 wt</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3733057','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3733057"><span>Equilibrium p-T Phase Diagram of Boron: Experimental Study and Thermodynamic <span class="hlt">Analysis</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Solozhenko, Vladimir L.; Kurakevych, Oleksandr O.</p> <p>2013-01-01</p> <p>Solid-state phase transformations and melting of high-purity crystalline boron have been in situ and ex situ studied at pressures to 20 <span class="hlt">GPa</span> in the 1500–2500 K temperature range where diffusion processes become fast and lead to formation of thermodynamically stable phases. The equilibrium phase diagram of boron has been constructed based on thermodynamic <span class="hlt">analysis</span> of experimental and literature data. The high-temperature part of the diagram contains p-T domains of thermodynamic stability of rhombohedral β-B106, orthorhombic γ-B28, pseudo-cubic (tetragonal) t'-B52, and liquid boron (L). The positions of two triple points have been experimentally estimated, i.e. β–t'–L at ~ 8.0 <span class="hlt">GPa</span> and ~ 2490 K; and β–γ–t' at ~ 9.6 <span class="hlt">GPa</span> and ~ 2230 K. Finally, the proposed phase diagram explains all thermodynamic aspects of boron allotropy and significantly improves our understanding of the fifth element. PMID:23912523</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..233a2022S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..233a2022S"><span>The results of pre-design studies on the development of a new design of gas turbine compressor package of <span class="hlt">GPA</span>-C-16 type</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smirnov, A. V.; Chobenko, V. M.; Shcherbakov, O. M.; Ushakov, S. M.; Parafiynyk, V. P.; Sereda, R. M.</p> <p>2017-08-01</p> <p>The article summarizes the results of <span class="hlt">analysis</span> of data concerning the operation of turbocompressor packages at compressor stations for the natural gas transmission system of Ukraine. The basic requirements for gas turbine compressor packages used for modernization and reconstruction of compressor stations are considered. Using a 16 MW gas turbine package <span class="hlt">GPA</span>-C-16S/76-1,44M1 as an example, the results of pre-design studies and some technical solutions that improve the energy efficiency of gas turbine compressor packages and their reliability, as well as its environmental performance are given. In particular, the article deals with the matching of performance characteristics of a centrifugal compressor (hereinafter compressor) and gas turbine drive to reduce fuel gas consumption; as well as application of energy efficient technologies, in particular, exhaust gas heat recovery units and gas-oil heat exchangers in turbocompressor packages oil system; as well as reducing emissions of carbon monoxide into the atmosphere using a catalytic exhaust system. Described technical solutions can be used for development of other types of gas turbine compressor packages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMDI14A..02Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMDI14A..02Y"><span>Phase transitions and Al partitioning in a pyrolitic MgO-Al2O3-SiO2 composition at 16-31 <span class="hlt">GPa</span> and 1500-2300 K</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ye, Y.; Gu, C.; Shim, S.; Prakapenka, V.; MacDowell, A.</p> <p>2013-12-01</p> <p>In order to understand strong seismic heterogeneities found in the base of the mantle transition zone, it is important to explore the effects of temperature and composition on the phase boundaries in the region. We have determined the phase boundaries near the 660-km discontinuity in an iron-free pyrolitic MgO-Al2O3-SiO2 (MAS) composition by combining in-situ synchrotron X-ray diffraction and laser-heated diamond-anvil cell at 16-31 <span class="hlt">GPa</span> and 1500-2300 K. The pyrolitic MAS composition glass starting materials were mixed with platinum (laser coupler and internal pressure scale) and loaded into the diamond-anvil cells together with argon (pressure transmitting medium and thermal insulator). The in-situ measurements were conducted at the GSECARS sector of Advanced Photon Source and beamline 12.2.2 of Advanced Light Source. We found that the post-spinel transition (ringwoodite to perovskite+periclase) occurs at the pressure and temperature conditions expected for the 660-km discontinuity at 1800 K if the shockwave platinum pressure scale by Holmes et al. (1989) is used. At temperatures above 1900 K, ringwoodite breaks down to garnet+periclase, instead of perovskite+periclase, followed by the post-garnet transition (garnet to perovskite) at the pressure-temperature conditions expected for warm heterogeneities at 650-680 km depths (23-24 <span class="hlt">GPa</span> and 1900-2300 K). The Clapeyron slopes of the post-spinel and post-garnet boundaries are constrained to be -2.8×0.2 and +2.4×0.3 MPa/K, respectively, indicating similar magnitude of thermal effects (with opposite signs) on the topography of the 660-km discontinuity by these phase boundaries. The dominance of the post-garnet transition above normal mantle temperatures will facilitate material exchange across the 660 discontinuity in warm mantle heterogeneities due to its positive Clapeyron slope. In our pyrolitic MAS composition, akimotoite was observed up to 2000-2300 K between 20 and 22 <span class="hlt">GPa</span> in both fresh sample heating and reversal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=psychological+AND+bulletin&pg=5&id=EJ962899','ERIC'); return false;" href="https://eric.ed.gov/?q=psychological+AND+bulletin&pg=5&id=EJ962899"><span>Psychological Correlates of University Students' Academic Performance: A Systematic Review and Meta-<span class="hlt">Analysis</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Richardson, Michelle; Abraham, Charles; Bond, Rod</p> <p>2012-01-01</p> <p>A review of 13 years of research into antecedents of university students' grade point average (<span class="hlt">GPA</span>) scores generated the following: a comprehensive, conceptual map of known correlates of tertiary <span class="hlt">GPA</span>; assessment of the magnitude of average, weighted correlations with <span class="hlt">GPA</span>; and tests of multivariate models of <span class="hlt">GPA</span> correlates within and across…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=342217','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=342217"><span>Chemical synthesis of 5'-pyrophosphate and triphosphate derivatives of 3'-5' ApA, ApG, <span class="hlt">GpA</span> and GpG. CD study of the effect of 5'-phosphate groups on the conformation of 3'-5' GpG.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tomasz, J; Simoncsits, A; Kajtár, M; Krug, R M; Shatkin, A J</p> <p>1978-01-01</p> <p>A simple, two-step method is described for the synthesis of the 5'-pyro- and triphosphate derivatives of 3'-5' ApA, ApG, <span class="hlt">GpA</span> and GpG. The readily accessible 2'(3')-5' ApA, ApG, <span class="hlt">GpA</span> and GpG were converted in one step to the corresponding 5'-phosphoramidate derivatives which were then transformed to the 5'-pyro- and triphosphates. CD spectra of 3'-5' pn GpG (n = 0,1,2 or 3) derivatives, measured at pH 1, indicated stabilization of the (syn) G+p (anti)G conformation by the 5'-phosphate groups. PMID:211490</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PEPI..271...47S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PEPI..271...47S"><span>Phase equilibria in the nominally Al65Cu23Fe12 system at 3, 5 and 21 <span class="hlt">GPa</span>: Implications for the quasicrystal-bearing Khatyrka meteorite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stagno, Vincenzo; Bindi, Luca; Steinhardt, Paul J.; Fei, Yingwei</p> <p>2017-10-01</p> <p>Two of the three natural quasiperiodic crystals found in the Khatyrka meteorite show a composition within the Al-Cu-Fe system. Icosahedrite, with formula Al63Cu24Fe13, coexists with the new Al62Cu31Fe7 quasicrystal plus additional Al-metallic minerals such as stolperite (AlCu), kryachkoite [(Al,Cu)6(Fe,Cu)], hollisterite (AlFe3), khatyrkite (Al2Cu) and cupalite (AlCu), associated to high-pressure phases like ringwoodite/ahrensite, coesite, and stishovite. These high-pressure minerals represent the evidence that most of the Khatyrka meteoritic fragments formed at least at 5 <span class="hlt">GPa</span> and 1200 °C, if not at more extreme conditions. On the other hand, experimental studies on phase equilibria within the representative Al-Cu-Fe system appear mostly limited to ambient pressure conditions, yet. This makes the interpretation of the coexisting mineral phases in the meteoritic sample quite difficult. We performed experiments at 3, 5 and 21 <span class="hlt">GPa</span> and temperatures of 800-1500 °C using the multi-anvil apparatus to investigate the phase equilibria in the Al65Cu23Fe12 system representative of the first natural quasicrystal, icosahedrite. Our results, supported by single-crystal X-ray diffraction and analyses by scanning electron microscopy, confirm the stability of icosahedrite at high pressure and temperature along with additional coexisting Al-bearing phases representative of khatyrkite and stolperite as those found in the natural meteorite. One reversal experiment performed at 5 <span class="hlt">GPa</span> and 1200 °C shows the formation of the icosahedral quasicrystal from a pure Al, Cu and Fe mixture, a first experimental synthesis of icosahedrite under those conditions. Pressure appears to not play a major role in the distribution of Al, Cu and Fe between the coexisting phases, icosahedrite in particular. Results from this study extend our knowledge on the stability of icosahedral AlCuFe at higher temperature and pressure than previously examined, and provide a new constraint on the stability of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMMR31A4312L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMMR31A4312L"><span>The melting curve of Ni to 125 <span class="hlt">GPa</span>: implications for Earth's Fe rich core alloy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lord, O. T.; Wood, I. G.; Dobson, D. P.; Vocadlo, L.; Thomson, A. R.; Wann, E.; Wang, W.; Edgington, A.; Morard, G.; Mezouar, N.; Walter, M. J.</p> <p>2014-12-01</p> <p>The melting curve of Ni has been determined to 125 <span class="hlt">GPa</span> using laser-heated diamond anvil cell (LH-DAC) experiments and two melting criteria: the appearance of liquid diffuse scattering (LDS) during in situ X-ray diffraction (XRD) and simultaneous plateaux in temperature vs. laser power functions [1]. Our melting curve (Fig. 1) is in good agreement with most theoretical studies [e.g. 2] and the available shock wave data (Fig. 2). It is, however, dramatically steeper than the previous off-line LH-DAC studies in which the determination of melting was based on the visual observation of motion aided by the laser speckle method [e.g. 3]. We estimate the melting point of Ni at the inner-core boundary (ICB; 330 <span class="hlt">GPa</span>) to be 5800±700 K (2σ), ~2500 K higher than the estimate based on the laser speckle method [3] and within error of Fe (6230±500 K) as determined in a similar in situ LH-DAC study [4]. We find that laser speckle based melting curves coincide with the onset of rapid sub-solidus recrystallization, suggesting that visual observations of motion may have misinterpreted dynamic recrystallization as melt convection. Our new melting curve suggests that the reduction in ICB temperature due to the alloying of Ni with Fe is likely to be significantly smaller than would be expected had the earlier experimental Ni melting studies been correct. We have applied our methodology to a range of other transition metals (Mo, Ti, V, Cu). In the case of Mo, Ti and V the melting curves are in good agreement with the shock compression and theoretical melting studies but hotter and steeper than those based on the laser speckle method, as with Ni. Cu is an exception in which all studies agree, including those employing the laser speckle method. These results go a long way toward resolving the the long-standing controversy over the phase diagrams of the transition metals as determined from static LH-DAC studies on the one hand, and theoretical and dynamic compression studies on the other</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29413406','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29413406"><span>2D strain mapping using scanning transmission electron microscopy Moiré interferometry and geometrical phase <span class="hlt">analysis</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pofelski, A; Woo, S Y; Le, B H; Liu, X; Zhao, S; Mi, Z; Löffler, S; Botton, G A</p> <p>2018-04-01</p> <p>A strain characterization technique based on Moiré interferometry in a scanning transmission electron microscope (STEM) and geometrical phase <span class="hlt">analysis</span> (<span class="hlt">GPA</span>) method is demonstrated. The deformation field is first captured in a single STEM Moiré hologram composed of multiple sets of periodic fringes (Moiré patterns) generated from the interference between the periodic scanning grating, fixing the positions of the electron probe on the sample, and the crystal structure. Applying basic principles from sampling theory, the Moiré patterns arrangement is then simulated using a STEM electron micrograph reference to convert the experimental STEM Moiré hologram into information related to the crystal lattice periodicities. The <span class="hlt">GPA</span> method is finally applied to extract the 2D relative strain and rotation fields. The STEM Moiré interferometry enables the local information to be de-magnified to a large length scale, comparable to what can be achieved in dark-field electron holography. The STEM Moiré <span class="hlt">GPA</span> method thus extends the conventional high-resolution STEM <span class="hlt">GPA</span> capabilities by providing comparable quantitative 2D strain mapping with a larger field of view (up to a few microns). Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4842915V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4842915V"><span>DIY EOS: Experimentally Validated Equations of State for Planetary Fluids to <span class="hlt">GPa</span> Pressures, Tools for Understanding Planetary Processes and Habitability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vance, Steven; Brown, J. Michael; Bollengier, Olivier</p> <p>2016-10-01</p> <p>Sound speeds are fundamental to seismology, and provide a path allowing the accurate determination of thermodynamic potentials. Prior equations of state (EOS) for pure ammonia (Harr and Gallagher 1978, Tillner-Roth et al. 1993) are based primarily on measured densities and heat capacities. Sound speeds, not included in the fitting, are poorly predicted.We couple recent high pressure sound speed data with prior densities and heat capacities to generate a new equation of state. Our representation fits both the earlier lower pressure work as well as measured sound speeds to 4 <span class="hlt">GPa</span> and 700 K and the Hugoniot to 70 <span class="hlt">GPa</span> and 6000 K.In contrast to the damped polynomial representation previously used, our equation of state is based on local basis functions in the form of tensor b-splines. Regularization allows the thermodynamic surface to be continued into regimes poorly sampled by experiments. We discuss application of this framework for aqueous equations of state validated by experimental measurements. Preliminary equations of state have been prepared applying the local basis function methodology to aqueous NH3, Mg2SO4, NaCl, and Na2SO4. We describe its use for developing new equations of state, and provide some applications of the new thermodynamic data to the interior structures of gas giant planets and ocean worlds.References:L. Haar and J. S. Gallagher. Thermodynamic properties of ammonia. American Chemical Society and the American Institute of Physics for the National Bureau of Standards, 1978.R. Tillner-Roth, F. Harms-Watzenberg, and H. Baehr. Eine neue fundamentalgleichung fuer ammoniak. DKV TAGUNGSBERICHT, 20:67-67, 1993.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994Metro..30..543M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994Metro..30..543M"><span>FOREWORD: CCM Second International Seminar: Pressure Metrology from 1 kPa to 1 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Molinar, G. F.</p> <p>1994-01-01</p> <p>The Comité Consultatif pour la Masse et les Grandeurs Apparentées (CCM), through its High Pressure and Medium Pressure Working Groups, organized this Second International Seminar on Pressure Metrology from 1 kPa to 1 <span class="hlt">GPa</span>, which was held at the Laboratoire National d'Essais (LNE), Paris, France, from 2 to 4 June 1993. The scope of the seminar was to review the state of the art of pressure measurements in the 1 kPa to I <span class="hlt">GPa</span> pressure range and to present innovative contributions by standards laboratories, universities and industry. The seminar was organized in six sessions: liquid-column manometers; piston gauge pressure standards; properties of liquids and gases relevant to pressure metrology; pressure transducers and transfer standards; pressure standard comparison (methods and results); dynamic pressure measurements. Each session opened with the presentation of a review paper on major requirements in that field and, at the end of the seminar, a general discussion was organized on the actual limits of accuracy of static and dynamic pressure measurements in fluid media, and the fundamental problems in pressure metrology between 1 kPa and 1 <span class="hlt">GPa</span>. The seminar was attended by sixty scientists from twenty-four countries, all working in the field of pressure measurements. Forty-nine papers were presented. The participation of scientists from so many countries indicates the importance of pressure metrology from the scientific and industrial points of view. Most papers were presented by scientists from national standards laboratories, with eight papers from universities and four from industry. Eleven papers reported the results of cooperative work involving metrological institutions dealing with high pressure, generally national standards laboratories, an indication that scientific links are already well established at this level. Links are also strengthening between industry and standards laboratories. Although industrial participation at the seminar was relatively small</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMMR62B1074J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMMR62B1074J"><span>Effects of Iron and Pressure on the c11 Elastic Constant of (Mg,Fe)O Using a New GHz-Ultrasonic Diamond Cell With In-Situ X-ray Diffraction to 10 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jacobsen, S.; Spetzler, H.; Reichmann, H.; Mackwell, S.; Smyth, J.</p> <p>2002-12-01</p> <p>(Mg,Fe)O may be one of the most elastically anisotropic cubic minerals likely to occur in Earth's interior. At ambient P-T, pure MgO exhibits ~10% P-wave and ~13% S-wave anisotropy. The landmark single-crystal ultrasonic experiment of Chen et al. (1998) showed that increasing pressure reduces this anisotropy, leading to either zero anisotropy or a switch in sign of the anisotropy factor (A=2c44+c12)/c11-1) expected at ~20 <span class="hlt">GPa</span>. They also showed that on increasing temperature (at pressure) the value of A recovers to bench-top values at only 1000 K (at 8 <span class="hlt">GPa</span>). The effects of pressure and iron in amounts relevant to Earth's interior on the anisotropic elastic properties of (Mg,Fe)O are not yet known. With this and other questions at hand, we are undertaking hydrostatic single-crystal elasticity measurements on (Mg,Fe)O using GHz-ultrasonic interferometry. Thus far, we have determined the pressure derivative of c11 to a maximum hydrostatic pressure of 9 <span class="hlt">GPa</span>, resulting in linear derivatives (dc11/dP) = 9.4(1), 11.7(4), 9.8(4), and 9.4(2) for MgO, and (Mg,Fe)O with 15, 24, and 56 mol% FeO, respectively. This behavior is consistent with our previous results on the compositional dependence of the bulk modulus, which we observed to increase between MgO and (Mg,Fe)O with 25 mol% FeO, before decreasing towards non-stoichiometric Fe0.95O. Therefore we speculate that the decrease in dc11/dP for the highest Fe-content sample is due at least in part to defects. The experiments were carried out in a new GHz-ultrasonic diamond cell modeled after the classic three-pin Merrill-Bassett design. The cell is capable of pressures >10 <span class="hlt">GPa</span> and features a 60° opening for in-situ single-crystal X-ray diffraction. The anvil seats contain no glue or epoxy so the entire frame (Vascomax 250) may be heated, as we have done readily up to 300°C for annealing. Perhaps most notably, the ultrasonic measurements were made without the use of a bonding agent (such as glue or gold) between the sample and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000CoMP..138...27V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000CoMP..138...27V"><span>Partitioning of Mg, Ca, and Na between carbonatite melt and hydrous fluid at 0.1-0.2 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Veksler, Ilya V.; Keppler, Hans</p> <p></p> <p>Experimental studies of the element distribution between carbonatite melts and hydrous fluids are hampered by the fact that neither the fluid nor the melt can be isochemically quenched in conventional high-pressure vessels. In order to overcome this problem, we used a double-capsule technique to separate immiscible fluid and melt phases during and after the runs. The inner platinum capsules were charged with carbonate mixtures (CaCO3, MgCO3 and Na2CO3) and placed inside the outer capsules charged with distilled water and diamond powder. The latter was used as an inert trap for solids precipitating from the fluid on quenching. Carbonate melt and hydrous fluid equilibrated through a small hole left in the upper end of the inner capsule. The runs were performed in rapid-quench cold-seal pressure vessels at 0.1-0.2 <span class="hlt">GPa</span> and 700-900°C in the two-phase (fluid+melt) stability region. Both quenched melt and quenched fluid were dissolved in dilute HCl and analysed by inductively coupled plasma atomic emission spectroscopy. The results show that under all conditions investigated, fluid/melt partition coefficients for Ca and Mg are similar and several times smaller than those for Na. At 0.1 <span class="hlt">GPa</span> and a water/carbonatite ratio of 1 (by weight), the partition coefficients are DNa= 0.35+/- 0.02, DCa=0.09+/-0.02, and DMg=0.13+/- 0.01. Between 700 and 900°C, the effect of temperature on partitioning is negligible. However, DNa increases significantly with decreasing water/carbonatite ratio in the system. Our data show that the release of a hydrous fluid enriched in sodium and simultaneous crystallisation of calcite can transform an alkaline, vapour-saturated carbonatite melt into a body of pure calcite surrounded by zones of sodium metasomatism. Thus, it is quite possible that carbonate magmas with substantial amounts of alkalies were common parental liquids of plutonic carbonatites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMMR43A0869S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMMR43A0869S"><span>The Fe-Ni-(S) System at 23 <span class="hlt">GPa</span>: The Possibility of Strong Chemical Fractionation Between Phases in the Cores of the Earth, Mars and Mercury</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stewart, A. J.; Schmidt, M. W.</p> <p>2004-12-01</p> <p>The presence of nickel in the Earths core is widely accepted based on cosmochemical and seismological arguments. However, experimental studies into core compositions rarely include nickel, thus adding a degree of simplicity to otherwise complex experiments. Diamond-anvil cell studies have discovered that Fe-Ni alloys appear to separate into two phases upon heating above 10 <span class="hlt">GPa</span>: from a single hexagonally close-packed (hcp) phase to the presence of both hcp and face centered cubic (fcc) phases (Lin et al., 2002). Unfortunately, due to the small size of diamond-anvil cell samples, meaningful quantitative <span class="hlt">analysis</span> is commonly impossible. We have conducted multi-anvil experiments at 23 <span class="hlt">GPa</span> into the Fe-Ni system and have confirmed the presence of two phases in the sub-solidus system. The starting material for these experiments contains 6 wt% nickel, approximating the amount expected to be found in the Earths core (McDonough, 2003). In experiments to 1500° C (the highest temperature thus far examined), electron microprobe analyses show dramatic phase fractionation with charges separating into an iron-rich phase containing less than 1 wt% Ni and a nickel-rich phase containing as much as 98 wt% Ni. We have observed the effect over a range of more than 500° ºC; further experiments are underway to determine whether these phases both persist toward the melting point of the alloy. Multi-anvil experiments at 23 <span class="hlt">GPa</span> have also been conducted to examine the effect of nickel on the Fe-S system. Sulphur is an element favoured by many researchers as the light element component in the core of the Earth as well as that of Mars. Previous research has suggested that the addition of nickel to the Fe-S system results in the lowering of eutectic temperatures by about 75° C (Pike et al., 1999). The starting material for these experiments is the same as that used for the pure Fe-Ni experiments discussed above, with the addition of sulphur. Our results indicate a pseudo-binary, (Fe, Ni</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMMR33A4342G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMMR33A4342G"><span>How to measure heat capacity of metals at 10s to 100s of <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geballe, Z. M.; Townley, A.; Jeanloz, R.</p> <p>2014-12-01</p> <p>Adapting methods of calorimetry to the diamond-anvil cell can provide important new information for understanding planetary interiors. Here we show that heat capacity of metals can be measured to the 10-100 <span class="hlt">GPa</span> range by using AC electrical heating inside diamond anvil cells. Frequencies of f ≈ 1-100 MHz must be used to contain the heat within the sample of interest, as evidenced by numerical and physical models of heat flow: f > DinsCins2/(Csamdsam)2, where Dins is the thermal diffusivity of the insulation, Cins and Csam are specific heat capacities of insulation and metal sample, and dsam is sample thickness. Heat must be deposited uniformly (e.g. skin depth > sample thickness) for the most accurate and unambiguous measurements, thereby allowing measurement of the energetics of pre-melting, melting and partial melting of metals, including iron and its alloys. In principle, high-pressure calorimetry can be used to independently determine melting at high pressures, and also to quantify latent heats of fusion, thereby revealing the density of liquid metals at Earth core conditions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27179893','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27179893"><span>Physical symptom burden of post-treatment head and neck cancer patients influences their characterization of food: Findings of a repertory grid study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Álvarez-Camacho, M; Martínez-Michel, L; Gonella, S; Scrimger, R A; Chu, K P; Wismer, W V</p> <p>2016-06-01</p> <p>Dietary advice for post treatment head and neck cancer (HNC) patients emphasizes food characteristics of nutritional value and texture, and not patients' characterization of food. The aim of this study was to determine patients' characterization of food. Repertory grid interviews were conducted with 19 orally-fed HNC patients between 4 and 10 months post-treatment to characterize foods commonly eaten, avoided and eaten sometimes. Patients compared and rated 12 foods using their own descriptors. Data were analyzed by General <span class="hlt">Procrustes</span> <span class="hlt">Analysis</span> (<span class="hlt">GPA</span>). Socio-demographic status, taste and smell alterations, appetite and food intake data were also collected. Patient physical symptom burden was defined by University of Washington-Quality of Life Physical Function domain scores and used to stratify patients with "less physical symptom burden" (n = 11, score ≥ 61.7) or "greater physical symptom burden" (n = 8, score < 61.7). All patients used descriptors of taste, ease of eating, convenience, texture, potential to worsen symptoms and liking to characterize foods. Overall, avoided foods were characterized as having dry texture, while foods commonly eaten were characterized by their ease of eating and low potential to worsen symptoms. Descriptors of nutrition and smell were significant only for patients with greater physical symptom burden. Physical symptom burden influenced the characterization of foods among post-treatment HNC patients. Nutrition counseling must consider patients' physical symptom burden and the subsequent characterization of food that drive food selection or avoidance to facilitate dietary advice for adequate, appropriate and enjoyable food intake. Copyright © 2016 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMMR34A..04L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMMR34A..04L"><span>SINGLE CRYSTAL DIFFRACTION OF SIDERITE UP TO 54 <span class="hlt">GPA</span> AND HIGH PRESSURE-HIGH TEMPERATURE PHASES IN THE Fe-C-O SYSTEM (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lavina, B.; Dera, P. K.; Downs, R. T.</p> <p>2009-12-01</p> <p>Phases in the Fe-C-O system are of interest for the deep carbon cycle, they might play an important role in buffering the mantle fO2. Carbon is also common in the fluid phases that greatly influence the Earth’s processes. The study of the high pressure behavior of siderite and of the phases synthesized after laser heating offers a good opportunity to illustrate the advantages and importance of single crystal diffraction in the high pressure science. The structure of siderite, FeCO3, has been refined up to 54 <span class="hlt">GPa</span> across the spin pairing transition. Splitting of the diffraction peaks at the transition pressure provides unequivocal evidence of the sharpness of the spin crossover and of the absence of any intermediate volume and therefore of an intermediate spin state at ambient temperature. Diffraction intensities were collected in about 30 minutes at a bending magnet station (HPCAT, APS) and in about one minute at an insertion device station (GSECARS, APS). The quality of the refinement is unvaried in the investigated range, and the results obtained from the two different radiation and detectors are consistent. The refinements provide an accurate and robust determination of the dependence of bond distances and angles with pressure. Subtle structural rearrangements associated with the collapse of the octahedral cation size will be discussed. In situ laser heating is a very powerful method to study minerals at the actual P-T of the Earth’s deep interior. Overcoming the kinetic barriers required for bond breaking and atom diffusion, high pressure-high temperature phases may be synthesized. The <span class="hlt">analysis</span> of high-pressure phases is very challenging. Diffraction patterns are usually of moderate quality and resolution, furthermore in addition to the sample, the pattern contains the contribution of other phases such as those used to insulate the anvils, to provide a pressure medium and a pressure marker. In several cases after laser heating, we observed phase transitions</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JPCRD..40d3105M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JPCRD..40d3105M"><span>Equation of State for Solid Phase I of Carbon Dioxide Valid for Temperatures up to 800 K and Pressures up to 12 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martin Trusler, J. P.</p> <p>2011-12-01</p> <p>The available thermodynamic-property data for solid phase I of carbon dioxide ("dry ice") are reviewed and used to determine the parameters of a new fundamental equation of state constructed in the form of a Helmholtz energy function with temperature and molar volume as the independent variables. The experimental data considered include the pressure, molar volume, and isobaric heat capacity along the sublimation curve, the melting-pressure curve, and molar volume in the compressed solid at temperatures from 295 to 764 K and pressures up to 12 <span class="hlt">GPa</span>. The equation of state is based on the quasi-harmonic approximation, incorporating a Debye oscillator distribution for the vibrons, two discrete modes for the librons and a further three distinct modes for the internal vibrations of the CO2 molecule. A small anharmonic correction term is included, which is significant mainly in the region of the triple point. The estimated relative uncertainty of molar volume at specified temperature and pressure calculated from the equation of state is 0.02% on the sublimation curve and 1.5% in the compressed solid; for isobaric heat capacity on the sublimation curve, the uncertainty varies from 5.0% to 0.5% between 2 and 195 K. Auxiliary equations for the pressure and molar volume on the sublimation and melting curves are given. The equation of state is valid at temperatures from 0 to 800 K and at pressures from the solid-fluid phase boundary to 12 <span class="hlt">GPa</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4814317','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4814317"><span>Theranostic pretargeted radioimmunotherapy of colorectal cancer xenografts in mice using picomolar affinity Y-86- or Lu-177-DOTA-Bn binding scFv C825/<span class="hlt">GPA</span>33 IgG bispecific immunoconjugates</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cheal, Sarah M.; Xu, Hong; Guo, Hong-fen; Lee, Sang-gyu; Punzalan, Blesida; Chalasani, Sandhya; Fung, Edward K.; Jungbluth, Achim; Zanzonico, Pat B.; Carrasquillo, Jorge A.; O’Donoghue, Joseph; Smith-Jones, Peter M.; Wittrup, K. Dane; Cheung, Nai-Kong V.; Larson, Steven M.</p> <p>2015-01-01</p> <p>Purpose <span class="hlt">GPA</span>33 is a colorectal cancer (CRC) antigen with unique retention properties after huA33-mediated tumor targeting. We tested a pre-targeted radioimmunotherapy (PRIT) approach for CRC using a tetravalent bispecific antibody with dual specificity for <span class="hlt">GPA</span>33 tumor antigen and DOTA-Bn (radiolanthanide metal) complex. Methods PRIT was optimized in vivo by titrating sequential intravenous doses of huA33-C825, the dextran-based clearing agent (CA), and the C825-haptens 177Lu-or 86Y-DOTA-Bn in mice bearing the SW1222 subcutaneous (s.c.) CRC xenograft model. Results Using optimized PRIT, therapeutic indices (TIs) for tumor radiation absorbed dose of 73 (tumor/blood) and 12 (tumor/kidney) were achieved. Estimated absorbed doses (cGy/MBq) to tumor, blood, liver, spleen, and kidney for single-cycle PRIT were 65.8, 0.9 (TI: 73), 6.3 (TI: 10), 6.6 (TI: 10), and 5.3 (TI: 12), respectively. Two cycles of PRIT treatment (66.6 or 111 MBq 177Lu-DOTA-Bn) were safe and effective, with 9/9 complete responses of established s.c. tumors (100–700 mm3) and 2/9 alive without recurrence >140 d. Tumor log kill in this model was estimated to be 2.1–3.0 based time to 500-mm3 tumor recurrence. In addition, PRIT dosimetry/diagnosis was performed by PET imaging of the positron-emitting DOTA-hapten 86Y-DOTA-Bn. Conclusions We have developed anti-<span class="hlt">GPA</span>33 PRIT, as a triple-step theranostic strategy for pre-clinical detection, dosimetry and safe targeted radiotherapy of established human colorectal mouse xenografts. PMID:26596724</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16115828','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16115828"><span>Thin-plate spline <span class="hlt">analysis</span> of arch form in a Southern European population with an ideal natural occlusion.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Camporesi, Matteo; Franchi, Lorenzo; Baccetti, Tiziano; Antonini, Antonino</p> <p>2006-04-01</p> <p>The purpose of the present study was to identify the mean configuration of the clinical arch form in a sample of Southern European subjects with ideal natural occlusion by means of <span class="hlt">Procrustes</span> <span class="hlt">analysis</span>, and to compare the identified configuration with 10 commercially produced arch forms by means of thin-plate spline (TPS) <span class="hlt">analysis</span>. The sample comprised the study casts of 50 subjects (26 males and 24 females). The mean age of the sample was 26 years +/- 4 years. All subjects were young Caucasian adults of Southern European ancestry, and presented with an ideal natural occlusion. The three-dimensional (3D) co-ordinates of all dental points (facial axis points) were digitized using a 3D electromagnetic digitizer. The morphometric technique of TPS <span class="hlt">analysis</span> with permutation tests was used to compare the configurations of landmarks in the various specimens. No sexual dimorphism was found for either upper or lower arch forms when the shape of the arches was assessed independently from size. The commercially available arch form that showed the least, though statistically significant, shape difference with respect to the average calculated configuration was the Brader arch form.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/21436020-diagnosis-specific-prognostic-factors-indexes-treatment-outcomes-patients-newly-diagnosed-brain-metastases-multi-institutional-analysis-patients','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/21436020-diagnosis-specific-prognostic-factors-indexes-treatment-outcomes-patients-newly-diagnosed-brain-metastases-multi-institutional-analysis-patients"><span>Diagnosis-Specific Prognostic Factors, Indexes, and Treatment Outcomes for Patients With Newly Diagnosed Brain Metastases: A Multi-Institutional <span class="hlt">Analysis</span> of 4,259 Patients</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Sperduto, Paul W., E-mail: psperduto@mropa.co; Chao, Samuel T.; Sneed, Penny K.</p> <p>2010-07-01</p> <p>Purpose: Controversy endures regarding the optimal treatment of patients with brain metastases (BMs). Debate persists, despite many randomized trials, perhaps because BM patients are a heterogeneous population. The purpose of the present study was to identify significant diagnosis-specific prognostic factors and indexes (Diagnosis-Specific Graded Prognostic Assessment [DS-<span class="hlt">GPA</span>]). Methods and Materials: A retrospective database of 5,067 patients treated for BMs between 1985 and 2007 was generated from 11 institutions. After exclusion of the patients with recurrent BMs or incomplete data, 4,259 patients with newly diagnosed BMs remained eligible for <span class="hlt">analysis</span>. Univariate and multivariate analyses of the prognostic factors and outcomes bymore » primary site and treatment were performed. The significant prognostic factors were determined and used to define the DS-<span class="hlt">GPA</span> prognostic indexes. The DS-<span class="hlt">GPA</span> scores were calculated and correlated with the outcomes, stratified by diagnosis and treatment. Results: The significant prognostic factors varied by diagnosis. For non-small-cell lung cancer and small-cell lung cancer, the significant prognostic factors were Karnofsky performance status, age, presence of extracranial metastases, and number of BMs, confirming the original <span class="hlt">GPA</span> for these diagnoses. For melanoma and renal cell cancer, the significant prognostic factors were Karnofsky performance status and the number of BMs. For breast and gastrointestinal cancer, the only significant prognostic factor was the Karnofsky performance status. Two new DS-<span class="hlt">GPA</span> indexes were thus designed for breast/gastrointestinal cancer and melanoma/renal cell carcinoma. The median survival by <span class="hlt">GPA</span> score, diagnosis, and treatment were determined. Conclusion: The prognostic factors for BM patients varied by diagnosis. The original <span class="hlt">GPA</span> was confirmed for non-small-cell lung cancer and small-cell lung cancer. New DS-<span class="hlt">GPA</span> indexes were determined for other histologic types and correlated with the outcome</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA018875','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA018875"><span>Numerical <span class="hlt">Analysis</span> of Laminated, Orthotropic Composite Structures</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1975-11-01</p> <p>the meridian plane. In the first model , a nine degree-of-freedom, straight sided, tri- angular element was used. In this element, the three...E ■ 13.79 <span class="hlt">GPa</span> v«. ■ «25» 6.. ■ 4.82 <span class="hlt">GPa</span> ns its V . « .25, G. « 4.82 <span class="hlt">GPa</span> nt nt vst * ,4S» 6st * 1*379 6P...means zero values of axial accelera- tion, and angular acceleration and velocity for each load increment) NLINC (Number of load increments with time</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18849382','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18849382"><span>Effect of sex and carcass weight on sensory quality of goat meat of Cabrito Transmontano.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rodrigues, S; Teixeira, A</p> <p>2009-02-01</p> <p>The main purpose of this work was the characterization of Cabrito Transmontana goat kid carcass and meat, which is a Protected Origin Designation product. The effects of sex and carcass weight were studied. Sensory attributes of toughness, juiciness, flavor intensity, flavor quality, odor intensity, fiber presence (stringy), sweet intensity, and overall acceptability were evaluated in 60 males and females allocated to 3 carcass weight groups: 4, 6, and 8 kg. Sensory quality of meat was evaluated by a trained taste panel of 11 experts in 5 sessions. Generalized <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> was performed, and 93% of total variability was explained by the 2 first factors (axes). Correlation between sensory traits and factors 1 and 2 allowed the factors to be renamed as toughness/aroma and juiciness/acceptability, respectively. <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> indicated that a sex effect was detected by experts. Meat from males presented greater juiciness, flavor quality, and general acceptability than did meat from females. Cabrito Transmontano Protected Origin Designation includes animals from 4 to 9 kg of carcass weight. However, differences among them can be important, because the taste panel found differences between animals from distinct carcass weight ranges. Lighter weight carcasses were considered more tender with less flavor and odor intensity than heavier carcasses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=least+AND+squares+AND+matrix&id=EJ922150','ERIC'); return false;" href="https://eric.ed.gov/?q=least+AND+squares+AND+matrix&id=EJ922150"><span>The Rigid Orthogonal <span class="hlt">Procrustes</span> Rotation Problem</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>ten Berge, Jos M. F.</p> <p>2006-01-01</p> <p>The problem of rotating a matrix orthogonally to a best least squares fit with another matrix of the same order has a closed-form solution based on a singular value decomposition. The optimal rotation matrix is not necessarily rigid, but may also involve a reflection. In some applications, only rigid rotations are permitted. Gower (1976) has…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24878173','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24878173"><span>Visual field progression in glaucoma: what is the specificity of the Guided Progression <span class="hlt">Analysis</span>?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Artes, Paul H; O'Leary, Neil; Nicolela, Marcelo T; Chauhan, Balwantray C; Crabb, David P</p> <p>2014-10-01</p> <p>To estimate the specificity of the Guided Progression <span class="hlt">Analysis</span> (<span class="hlt">GPA</span>) (Carl Zeiss Meditec, Dublin, CA) in individual patients with glaucoma. Observational cohort study. Thirty patients with open-angle glaucoma. In 30 patients with open-angle glaucoma, 1 eye (median mean deviation [MD], -2.5 decibels [dB]; interquartile range, -4.4 to -1.3 dB) was tested 12 times over 3 months (Humphrey Field Analyzer, Carl Zeiss Meditec; SITA Standard, 24-2). "Possible progression" and "likely progression" were determined with the <span class="hlt">GPA</span>. These analyses were repeated after the order of the tests had been randomly rearranged (1000 unique permutations). Rate of false-positive alerts of "possible progression" and "likely progression" with the <span class="hlt">GPA</span>. On average, the specificity of the <span class="hlt">GPA</span> "likely progression" alert was high-for the entire sample, the mean rate of false-positive alerts after 10 follow-up tests was 2.6%. With "possible progression," the specificity was considerably lower (false-positive rate, 18.5%). Most important, the cumulative rate of false-positive alerts varied substantially among patients, from <1% to 80% with "possible progression" and from <0.1% to 20% with "likely progression." Factors associated with false-positive alerts were visual field variability (standard deviation of MD, Spearman's rho = 0.41, P<0.001) and the reliability indices (proportion of false-positive and false-negative responses, fixation losses, rho>0.31, P≤0.10). On average, progression criteria currently used in the <span class="hlt">GPA</span> have high specificity, but some patients are more likely to show false-positive alerts than others. This is a natural consequence of population-based change criteria and may not matter in clinical trials and studies in which large groups of patients are compared. However, it must be considered when the <span class="hlt">GPA</span> is used in clinical practice where specificity needs to be controlled for individual patients. Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29703402','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29703402"><span>FE <span class="hlt">analysis</span> of conceptual hybrid composite endodontic post designs in anterior teeth.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gloria, Antonio; Maietta, Saverio; Martorelli, Massimo; Lanzotti, Antonio; Watts, David C; Ausiello, Pietro</p> <p>2018-04-24</p> <p>To assess conceptual designs of dental posts consisting of polyetherimide (PEI) reinforced with carbon (C) and glass (G) glass fibers in endodontically treated anterior teeth. 3D tessellated CAD and geometric models of endodontically treated anterior teeth were generated from Micro-CT scan images. Model C-G/PEI composite posts with different Young's moduli were analyzed by Finite Element (FE) methods post A (57.7<span class="hlt">GPa</span>), post B (31.6<span class="hlt">GPa</span>), post C (from 57.7 to 9.0<span class="hlt">GPa</span> in the coronal-apical direction). A load of 50N was applied at 45° to the longitudinal axis of the tooth, acting on the palatal surface of the crown. The maximum principal stress distribution was determined along the post and at the interface between the post and the surrounding structure. Post C, with Young's modulus decreasing from 57.7 to 9.0<span class="hlt">GPa</span> in the coronal-apical direction, reduced the maximum principal stress distribution in the restored tooth. Post C gave reduced stress and the most uniform stress distribution with no stress concentration, compared to the other C-G/PEI composite posts. The FE <span class="hlt">analysis</span> confirmed the ability of the functionally graded post to dissipate stress from the coronal to the apical end. Hence actual (physical) C-G/PEI posts could permit optimization of stress distributions in endodontically treated anterior teeth. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28939223','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28939223"><span>Stereotactic Radiosurgery With or Without Whole-Brain Radiation Therapy for Limited Brain Metastases: A Secondary <span class="hlt">Analysis</span> of the North Central Cancer Treatment Group N0574 (Alliance) Randomized Controlled Trial.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Churilla, Thomas M; Ballman, Karla V; Brown, Paul D; Twohy, Erin L; Jaeckle, Kurt; Farace, Elana; Cerhan, Jane H; Anderson, S Keith; Carrero, Xiomara W; Garces, Yolanda I; Barker, Fred G; Deming, Richard; Dixon, Jesse G; Burri, Stuart H; Chung, Caroline; Ménard, Cynthia; Stieber, Volker W; Pollock, Bruce E; Galanis, Evanthia; Buckner, Jan C; Asher, Anthony L</p> <p>2017-12-01</p> <p>To determine whether whole-brain radiation therapy (WBRT) is associated with improved overall survival among non-small cell lung cancer (NSCLC) patients with favorable prognoses at diagnosis. In the N0574 trial, patients with 1 to 3 brain metastases were randomized to receive stereotactic radiosurgery (SRS) or SRS plus WBRT (SRS + WBRT), with a primary endpoint of cognitive deterioration. We calculated diagnosis-specific graded prognostic assessment (DS-<span class="hlt">GPA</span>) scores for NSCLC patients and evaluated overall survival according to receipt of WBRT and DS-<span class="hlt">GPA</span> score using 2 separate cut-points (≥2.0 vs <2.0 and ≥2.5 vs <2.5). A total of 126 NSCLC patients were included for <span class="hlt">analysis</span>, with median follow-up of 14.2 months. Data for DS-<span class="hlt">GPA</span> calculation were available for 86.3% of all enrolled NSCLC patients. Overall, 50.0% of patients had DS-<span class="hlt">GPA</span> score ≥2.0, and 23.0% of patients had DS-<span class="hlt">GPA</span> scores ≥2.5. The SRS and SRS + WBRT groups were well balanced with regard to prognostic factors. The median survival according to receipt of WBRT was 11.3 months (+WBRT) and 17.9 months (-WBRT) for patients with DS-<span class="hlt">GPA</span> ≥2.0 (favorable prognoses, P=.63; hazard ratio 0.86; 95% confidence interval 0.47-1.59). Median survival was 3.7 months (+WBRT) and 6.6 months (-WBRT) for patients with DS-<span class="hlt">GPA</span> <2.0 patients (unfavorable prognoses, P=.85; hazard ratio 0.95; 95% confidence interval 0.56-1.62). Outcomes according to the receipt of WBRT and DS-<span class="hlt">GPA</span> remained similar utilizing DS-<span class="hlt">GPA</span> ≥2.5 as a cutoff for favorable prognoses. There was no interaction between the continuum of the DS-<span class="hlt">GPA</span> groups and WBRT on overall survival (P=.53). We observed no significant differences in survival according to receipt of WBRT in favorable-prognosis NSCLC patients. This study further supports the approach of SRS alone in the majority of patients with limited brain metastases. Copyright © 2017 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=LUNG+AND+SIMULATION&pg=2&id=EJ736329','ERIC'); return false;" href="https://eric.ed.gov/?q=LUNG+AND+SIMULATION&pg=2&id=EJ736329"><span>Generalized Path <span class="hlt">Analysis</span> and Generalized Simultaneous Equations Model for Recursive Systems with Responses of Mixed Types</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Tsai, Tien-Lung; Shau, Wen-Yi; Hu, Fu-Chang</p> <p>2006-01-01</p> <p>This article generalizes linear path <span class="hlt">analysis</span> (PA) and simultaneous equations models (SiEM) to deal with mixed responses of different types in a recursive or triangular system. An efficient instrumental variable (IV) method for estimating the structural coefficients of a 2-equation partially recursive generalized path <span class="hlt">analysis</span> (<span class="hlt">GPA</span>) model and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMMR21B2639Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMMR21B2639Q"><span>P-V-T equation of state of clinohumite up to 25 <span class="hlt">GPa</span> and 750 K</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qin, F.; Wu, X.; Jacobsen, S. D.; Zhang, D.</p> <p>2016-12-01</p> <p>The dense hydrous magnesium silicate (DHMS) minerals along the brucite-forsterite join have been proposed as the major carriers of water into the Earth's mantle. The natural occurrence of humite-group minerals makes knowledge of their phase relations and crystal chemistry under high pressure and temperature conditions important to geochemical and geophysical studies of volatile cycling between the crust and upper mantle. In natural high-grade metamorphic rocks and carbonates, clinohumite (P21/c) typically contains F at the hydroxyl site and Ti in one of the octahedral sites. Here, we have studied the thermal and compressional behaviors of clinohumite up to 25 <span class="hlt">GPa</span> and 750 K. Synchrotron X-ray diffraction of single-crystal clinohumite was carried out at the 13 BMC beamline (GSECARS) of the Advanced Photon Source. Our experimental results clearly show that there is no indication of structural phase transition of clinohumite at high P-T conditions relevant to the subducted zone environments. Knowledge of humite-group crystal chemistry at high P-T conditions will also contribute more broadly to the field of mineralogy because of the morphotropic relationship with the minerals olivine and brucite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930048461&hterms=stress+good&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dstress%2Bgood','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930048461&hterms=stress+good&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dstress%2Bgood"><span>Micromechanics thermal stress <span class="hlt">analysis</span> of composites for space structure applications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bowles, David E.</p> <p>1991-01-01</p> <p>This paper presents results from a finite element micromechanics <span class="hlt">analysis</span> of thermally induced stresses in composites at cryogenic temperatures typical of spacecraft operating environments. The influence of microstructural geometry, constituent and interphase properties, and laminate orientation were investigated. Stress field results indicated that significant matrix stresses occur in composites exposed to typical spacecraft thermal excursions; these stresses varied with laminate orientation and circumferential position around the fiber. The major difference in the predicted response of unidirectional and multidirectional laminates was the presence of tensile radial stresses, at the fiber/matrix interface, in multidirectional laminates with off-axis ply angles greater than 15 deg. The predicted damage initiation temperatures and modes were in good agreement with experimental data for both low (207 <span class="hlt">GPa</span>) and high (517 <span class="hlt">GPa</span>) modulus carbon fiber/epoxy composites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1055517-infrared-emissivity-tin-upon-release-gpa-shock-lif-window','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1055517-infrared-emissivity-tin-upon-release-gpa-shock-lif-window"><span>Infrared Emissivity of Tin upon Release of a 25 <span class="hlt">GPa</span> Shock into a LiF Window</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Turley, W. D., Holtkamp, D. B., Marshall, B. R., Stevens, G. D., Veeser, L. R.</p> <p></p> <p>We measured the emissivity of a tin sample at its interface with a lithium-fluoride window upon release of a 25 <span class="hlt">GPa</span> shock wave from the tin into the window. Measurements were made over four wavelength bands between 1.2 and 5.4 μm. Thermal emission backgrounds from the tin, glue, and lithium fluoride were successfully removed from the reflectance signals. Emissivity changes for the sample, which was initially nearly specular, were small except for the longest wavelength band, where uncertainties were high because of poor signal-to-noise ratio at that wavelength. A thin glue layer, which bonds the sample to the window, wasmore » found to heat from reverberations of the shock wave between the tin and the lithium fluoride. At approximately 3.4 μm the thermal emission from the glue was large compared to the tin, allowing a good estimate of the glue temperature from the thermal radiance. The glue appears to remain slightly colder than the tin, thereby minimizing heat conduction into or out of the tin immediately after the shock passage.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED531721.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED531721.pdf"><span>International Academic Success: Institutional Planning & <span class="hlt">Analysis</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hamilton, Kristen; Kennedy, Matthew; Crespin-Mueller, Dorys</p> <p>2010-01-01</p> <p>This study was requested by the Senate International Affairs Committee. The research questions included: (1) What factors affect the cumulative <span class="hlt">GPA</span> (CGPA) of International students at TRU?; (2) What factors affect the retention of International students at TRU?; and (3) Are Student Success Courses among the significant factors for <span class="hlt">GPA</span> and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DokES.474..680S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DokES.474..680S"><span>Stability of methane in reduced C-O-H fluid at 6.3 <span class="hlt">GPa</span> and 1300-1400°C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sokol, A. G.; Tomilenko, A. A.; Bul'bak, T. A.; Palyanova, G. A.; Palyanov, Yu. N.; Sobolev, N. V.</p> <p>2017-06-01</p> <p>The composition of a reduced C-O-H fluid was studied by the method of chromatography-mass spectrometry under the conditions of 6.3 <span class="hlt">GPa</span>, 1300-1400°C, and fO2 typical of the base of the subcratonic lithosphere. Fluids containing water (4.4-96.3 rel. %), methane (37.6-0.06 rel. %), and variable concentrations of ethane, propane, and butane were obtained in experiments. With increasing fO2, the proportion of the CH4/C2H6 peak areas on chromatograms first increases and then decreases, whereas the CH4/C3H8 and CH4/C4H10 ratios continually decrease. The new data show that ethane and heavier HCs may be more stable to oxidation, than previously thought. Therefore, when reduced fluids pass the "redox-front," carbon is not completely released from the fluid and may be involved in diamond formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24781944','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24781944"><span>Hierarchical cluster <span class="hlt">analysis</span> of progression patterns in open-angle glaucoma patients with medical treatment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bae, Hyoung Won; Rho, Seungsoo; Lee, Hye Sun; Lee, Naeun; Hong, Samin; Seong, Gong Je; Sung, Kyung Rim; Kim, Chan Yun</p> <p>2014-04-29</p> <p>To classify medically treated open-angle glaucoma (OAG) by the pattern of progression using hierarchical cluster <span class="hlt">analysis</span>, and to determine OAG progression characteristics by comparing clusters. Ninety-five eyes of 95 OAG patients who received medical treatment, and who had undergone visual field (VF) testing at least once per year for 5 or more years. OAG was classified into subgroups using hierarchical cluster <span class="hlt">analysis</span> based on the following five variables: baseline mean deviation (MD), baseline visual field index (VFI), MD slope, VFI slope, and Glaucoma Progression <span class="hlt">Analysis</span> (<span class="hlt">GPA</span>) printout. After that, other parameters were compared between clusters. Two clusters were made after a hierarchical cluster <span class="hlt">analysis</span>. Cluster 1 showed -4.06 ± 2.43 dB baseline MD, 92.58% ± 6.27% baseline VFI, -0.28 ± 0.38 dB per year MD slope, -0.52% ± 0.81% per year VFI slope, and all "no progression" cases in <span class="hlt">GPA</span> printout, whereas cluster 2 showed -8.68 ± 3.81 baseline MD, 77.54 ± 12.98 baseline VFI, -0.72 ± 0.55 MD slope, -2.22 ± 1.89 VFI slope, and seven "possible" and four "likely" progression cases in <span class="hlt">GPA</span> printout. There were no significant differences in age, sex, mean IOP, central corneal thickness, and axial length between clusters. However, cluster 2 included more high-tension glaucoma patients and used a greater number of antiglaucoma eye drops significantly compared with cluster 1. Hierarchical cluster <span class="hlt">analysis</span> of progression patterns divided OAG into slow and fast progression groups, evidenced by assessing the parameters of glaucomatous progression in VF testing. In the fast progression group, the prevalence of high-tension glaucoma was greater and the number of antiglaucoma medications administered was increased versus the slow progression group. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26596724','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26596724"><span>Theranostic pretargeted radioimmunotherapy of colorectal cancer xenografts in mice using picomolar affinity ⁸⁶Y- or ¹⁷⁷Lu-DOTA-Bn binding scFv C825/<span class="hlt">GPA</span>33 IgG bispecific immunoconjugates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cheal, Sarah M; Xu, Hong; Guo, Hong-Fen; Lee, Sang-Gyu; Punzalan, Blesida; Chalasani, Sandhya; Fung, Edward K; Jungbluth, Achim; Zanzonico, Pat B; Carrasquillo, Jorge A; O'Donoghue, Joseph; Smith-Jones, Peter M; Wittrup, K Dane; Cheung, Nai-Kong V; Larson, Steven M</p> <p>2016-05-01</p> <p><span class="hlt">GPA</span>33 is a colorectal cancer (CRC) antigen with unique retention properties after huA33-mediated tumor targeting. We tested a pretargeted radioimmunotherapy (PRIT) approach for CRC using a tetravalent bispecific antibody with dual specificity for <span class="hlt">GPA</span>33 tumor antigen and DOTA-Bn-(radiolanthanide metal) complex. PRIT was optimized in vivo by titrating sequential intravenous doses of huA33-C825, the dextran-based clearing agent, and the C825 haptens (177)Lu-or (86)Y-DOTA-Bn in mice bearing the SW1222 subcutaneous (s.c.) CRC xenograft model. Using optimized PRIT, therapeutic indices (TIs) for tumor radiation-absorbed dose of 73 (tumor/blood) and 12 (tumor/kidney) were achieved. Estimated absorbed doses (cGy/MBq) to tumor, blood, liver, spleen, and kidney for single-cycle PRIT were 65.8, 0.9 (TI 73), 6.3 (TI 10), 6.6 (TI 10), and 5.3 (TI 12), respectively. Two cycles of PRIT (66.6 or 111 MBq (177)Lu-DOTA-Bn) were safe and effective, with a complete response of established s.c. tumors (100 - 700 mm(3)) in nine of nine mice, with two mice alive without recurrence at >140 days. Tumor log kill in this model was estimated to be 2.1 - 3.0 based on time to 500-mm(3) tumor recurrence. In addition, PRIT dosimetry/diagnosis was performed by PET imaging of the positron-emitting DOTA hapten (86)Y-DOTA-Bn. We have developed anti-<span class="hlt">GPA</span>33 PRIT as a triple-step theranostic strategy for preclinical detection, dosimetry, and safe targeted radiotherapy of established human colorectal mouse xenografts.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26181254','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26181254"><span>Stereotactic Radiosurgery With or Without Whole-Brain Radiotherapy for Brain Metastases: Secondary <span class="hlt">Analysis</span> of the JROSG 99-1 Randomized Clinical Trial.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Aoyama, Hidefumi; Tago, Masao; Shirato, Hiroki</p> <p>2015-07-01</p> <p>It remains uncertain whether treatment with stereotactic radiosurgery (SRS) alone can be safely applied to all patient populations with 1 to 4 brain metastases (BMs) exhibiting heterogeneous prognoses. To investigate the feasibility of SRS alone for patients with different prognoses determined by the diagnosis-specific Graded Prognostic Assessment (DS-<span class="hlt">GPA</span>). A secondary <span class="hlt">analysis</span> (performed in September 2014) of the Japanese Radiation Oncology Study Group (JROSG) 99-1, a phase 3 randomized trial, comparing SRS alone and whole-brain radiotherapy (WBRT) + SRS conducted in 1999 to 2003. Among a total of 132 patients, 88 with non-small-cell lung cancer (NSCLC) and 1 to 4 BMs were included and poststratified by DS-<span class="hlt">GPA</span> scores to avoid potential bias from BMs from different primary cancer types. The median follow-up time was 8.05 months. The WBRT schedule was 30 Gy in 10 fractions over 2 to 2.5 weeks. The mean SRS dose was 21.9 Gy in SRS alone and 16.6 Gy in WBRT + SRS. The primary end point was overall survival (OS), and the secondary end points included brain tumor recurrence (BTR), salvage treatment, and radiation toxic effects. Forty-seven patients had a favorable prognosis, with DS-<span class="hlt">GPA</span> scores of 2.5 to 4.0 (26 SRS-alone and 21 WBRT + SRS [DS-<span class="hlt">GPA</span> 2.5-4.0 group]), and 41 had an unfavorable prognosis, with DS-<span class="hlt">GPA</span> scores of 0.5 to 2.0 (19 SRS-alone and 22 WBRT + SRS [DS-<span class="hlt">GPA</span> 0.5-2.0 group]). Significantly better OS was observed in the DS-<span class="hlt">GPA</span> 2.5-4.0 group in WBRT + SRS vs the SRS alone, with a median survival time of 16.7 (95% CI, 7.5-72.9) months vs 10.6 (95% CI, 7.7-15.5) months (P = .04) (hazard ratio [HR], 1.92; 95% CI, 1.01-3.78). However, no such difference was observed in the DS-<span class="hlt">GPA</span> 0.5-2.0 group (HR, 1.05; 95% CI, 0.55-1.99) (P = .86). This benefit could be explained by the differing BTR rates, in that the prevention against BTR by WBRT had a more significant impact in the DS-<span class="hlt">GPA</span> 2.5-4.0 group (HR, 8.31; 95% CI, 3.05-29.13) (P < .001</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28961826','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28961826"><span>Whole brain radiotherapy after stereotactic radiosurgery or surgical resection among patients with one to three brain metastases and favorable prognoses: a secondary <span class="hlt">analysis</span> of EORTC 22952-26001.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Churilla, T M; Handorf, E; Collette, S; Collette, L; Dong, Y; Aizer, A A; Kocher, M; Soffietti, R; Alexander, B M; Weiss, S E</p> <p>2017-10-01</p> <p>The absence of a survival benefit for whole brain radiotherapy (WBRT) among randomized trials has been attributed to a competing risk of death from extracranial disease. We re-analyzed EORTC 22952 to assess the impact of WBRT on survival for patients with controlled extracranial disease or favorable prognoses. We utilized Cox regression, landmark <span class="hlt">analysis</span>, and the Kaplan-Meier method to evaluate the impact of WBRT on survival accounting for (i) extracranial progression as a time-dependent covariate in all patients and (ii) diagnosis-specific graded prognostic assessment (<span class="hlt">GPA</span>) score in patients with primary non-small-cell lung cancer (NSCLC). A total of 329 patients treated per-protocol were included for <span class="hlt">analysis</span> with a median follow up of 26 months. One hundred and fifteen (35%) patients had no extracranial progression; 70 (21%) patients had progression <90 days, 65 (20%) between 90 and 180 days, and 79 (24%) patients >180 days from randomization. There was no difference in the model-based risk of death in the WBRT group before [hazard ratio (HR) (95% CI)=0.70 (0.45-1.11), P = 0.133), or after [HR (95% CI)=1.20 (0.89-1.61), P = 0.214] extracranial progression. Among 177 patients with NSCLC, 175 had data available for <span class="hlt">GPA</span> calculation. There was no significant survival benefit to WBRT among NSCLC patients with favorable <span class="hlt">GPA</span> scores [HR (95% CI)=1.10 (0.68-1.79)] or unfavorable <span class="hlt">GPA</span> scores [HR (95% CI)=1.11 (0.71-1.76)]. Among patients with limited extracranial disease and one to three brain metastases at enrollment, we found no significant survival benefit to WBRT among NSCLC patients with favorable <span class="hlt">GPA</span> scores or patients with any histology and controlled extracranial disease status. This exploratory <span class="hlt">analysis</span> of phase III data supports the practice of omitting WBRT for patients with limited brain metastases undergoing SRS and close surveillance. NCT00002899. © The Author 2017. Published by Oxford University Press on behalf of the European Society for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27829191','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27829191"><span>Determination of replicate composite bone material properties using modal <span class="hlt">analysis</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Leuridan, Steven; Goossens, Quentin; Pastrav, Leonard; Roosen, Jorg; Mulier, Michiel; Denis, Kathleen; Desmet, Wim; Sloten, Jos Vander</p> <p>2017-02-01</p> <p>Replicate composite bones are used extensively for in vitro testing of new orthopedic devices. Contrary to tests with cadaveric bone material, which inherently exhibits large variability, they offer a standardized alternative with limited variability. Accurate knowledge of the composite's material properties is important when interpreting in vitro test results and when using them in FE models of biomechanical constructs. The cortical bone analogue material properties of three different fourth-generation composite bone models were determined by updating FE bone models using experimental and numerical modal analyses results. The influence of the cortical bone analogue material model (isotropic or transversely isotropic) and the inter- and intra-specimen variability were assessed. Isotropic cortical bone analogue material models failed to represent the experimental behavior in a satisfactory way even after updating the elastic material constants. When transversely isotropic material models were used, the updating procedure resulted in a reduction of the longitudinal Young's modulus from 16.00<span class="hlt">GPa</span> before updating to an average of 13.96 <span class="hlt">GPa</span> after updating. The shear modulus was increased from 3.30<span class="hlt">GPa</span> to an average value of 3.92<span class="hlt">GPa</span>. The transverse Young's modulus was lowered from an initial value of 10.00<span class="hlt">GPa</span> to 9.89<span class="hlt">GPa</span>. Low inter- and intra-specimen variability was found. Copyright © 2016 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoOD..60...82S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoOD..60...82S"><span>Morphological Features of Diamond Crystals Dissolved in Fe0.7S0.3 Melt at 4 <span class="hlt">GPa</span> and 1400°C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sonin, V. M.; Zhimulev, E. I.; Pomazanskiy, B. S.; Zemnuhov, A. L.; Chepurov, A. A.; Afanasiev, V. P.; Chepurov, A. I.</p> <p>2018-01-01</p> <p>An experimental study of the dissolution of natural and synthetic diamonds in a sulfur-bearing iron melt (Fe0.7S0.3) with high P-T parameters (4 <span class="hlt">GPa</span>, 1400°C) was performed. The results demonstrated that under these conditions, octahedral crystals with flat faces and rounded tetrahexahedral diamond crystals are transformed into rounded octahedroids, which have morphological characteristics similar to those of natural diamonds from kimberlite. It was suggested that, taking into account the complex history of individual natural diamond crystals, including the dissolution stages, sulfur-bearing metal melts up to sulfide melts were not only diamond-forming media during the early evolution of the Earth, but also natural solvents of diamond in the mantle environment before the formation of kimberlitic melts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22822302','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22822302"><span>Factors influencing societal response of nanotechnology: an expert stakeholder <span class="hlt">analysis</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gupta, Nidhi; Fischer, Arnout R H; van der Lans, Ivo A; Frewer, Lynn J</p> <p>2012-05-01</p> <p>Nanotechnology can be described as an emerging technology and, as has been the case with other emerging technologies such as genetic modification, different socio-psychological factors will potentially influence societal responses to its development and application. These factors will play an important role in how nanotechnology is developed and commercialised. This article aims to identify expert opinion on factors influencing societal response to applications of nanotechnology. Structured interviews with experts on nanotechnology from North West Europe were conducted using repertory grid methodology in conjunction with generalized <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> to examine the psychological constructs underlying societal uptake of 15 key applications of nanotechnology drawn from different areas (e.g. medicine, agriculture and environment, chemical, food, military, sports, and cosmetics). Based on expert judgement, the main factors influencing societal response to different applications of nanotechnology will be the extent to which applications are perceived to be beneficial, useful, and necessary, and how 'real' and physically close to the end-user these applications are perceived to be by the public. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11051-012-0857-x) contains supplementary material, which is available to authorized users.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRB..122.5064S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRB..122.5064S"><span>Constant electrical resistivity of Ni along the melting boundary up to 9 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Silber, Reynold E.; Secco, Richard A.; Yong, Wenjun</p> <p>2017-07-01</p> <p>Characterization of transport properties of liquid Ni at high pressures has important geophysical implications for terrestrial planetary interiors, because Ni is a close electronic analogue of Fe and it is also integral to Earth's core. We report measurements of the electrical resistivity of solid and liquid Ni at pressures 3-9 <span class="hlt">GPa</span> using a 3000 t multianvil large volume press. A four-wire method, in conjunction with a rapid acquisition meter and polarity switch, was used to overcome experimental challenges such as melt containment and maintaining sample geometry and to mitigate the extreme reactivity/solubility of liquid Ni with most thermocouple and electrode materials. Thermal conductivity is calculated using the Wiedemann-Franz law. Electrical resistivity of solid Ni exhibits the expected P dependence and is consistent with earlier experimental values. Within experimental uncertainties, our results indicate that resistivity of liquid Ni remains invariant along the P-dependent melting boundary, which is in disagreement with earlier prediction for liquid transition metals. The potential reasons for such behavior are examined qualitatively through the impact of P-independent local short-range ordering on electron mean free path and the possibility of constant Fermi surface at the onset of Ni melting. Correlation among metals obeying the Kadowaki-Woods ratio and the group of late transition metals with unfilled d-electron band displaying anomalously shallow melting curves suggests that on the melting boundary, Fe may exhibit the same resistivity behavior as Ni. This could have important implications for the heat flow in the Earth's core.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JPhCS.902a2021V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JPhCS.902a2021V"><span>Strategy for reliable strain measurement in InAs/GaAs materials from high-resolution Z-contrast STEM images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vatanparast, Maryam; Vullum, Per Erik; Nord, Magnus; Zuo, Jian-Min; Reenaas, Turid W.; Holmestad, Randi</p> <p>2017-09-01</p> <p>Geometric phase <span class="hlt">analysis</span> (<span class="hlt">GPA</span>), a fast and simple Fourier space method for strain <span class="hlt">analysis</span>, can give useful information on accumulated strain and defect propagation in multiple layers of semiconductors, including quantum dot materials. In this work, <span class="hlt">GPA</span> has been applied to high resolution Z-contrast scanning transmission electron microscopy (STEM) images. Strain maps determined from different g vectors of these images are compared to each other, in order to analyze and assess the <span class="hlt">GPA</span> technique in terms of accuracy. The SmartAlign tool has been used to improve the STEM image quality getting more reliable results. Strain maps from template matching as a real space approach are compared with strain maps from <span class="hlt">GPA</span>, and it is discussed that a real space <span class="hlt">analysis</span> is a better approach than <span class="hlt">GPA</span> for aberration corrected STEM images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1613515T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1613515T"><span>Composition of COH fluids at 1 <span class="hlt">GPa</span>: an experimental study on speciation and solubility</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tiraboschi, Carla; Tumiati, Simone; Recchia, Sandro; Ulmer, Peter; Pettke, Thomas; Fumagalli, Patrizia; Poli, Stefano</p> <p>2014-05-01</p> <p>COH fluids play a fundamental role in many geological processes, controlling the location of melting in subduction zones and promoting mass transfer from the subducting litosphere to the overlying mantle wedge. The properties of COH fluids are strictly dependent on the composition of the fluid in subduction systems, i.e., the speciation of the volatile components of the fluid itself and the presence of solutes deriving from the dissolution of rock-forming minerals. In the scientific literature, the speciation of COH fluids has been generally determined through thermodynamic calculations using equations of state of simple H2O-non-polar gas systems (e.g., H2O-CO2-CH4), equations that do not consider the complexity related to dissolution processes, which are substantially unexplored in COH fluids and limited so far to aqueous fluids (Newton & Manning, 2002). The aim of this work is to investigate experimentally the speciation and the dissolution of mantle minerals in carbon-saturated COH fluids at buffered fO2 conditions. Our experimental approach relies on two different techniques: 1) <span class="hlt">analysis</span> by means of quadrupole mass spectrometer (QMS) of the fluids from pierced run capsules to retrieve speciation of volatile components and 2) <span class="hlt">analysis</span> of frozen COH fluid with laser-ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) to measure the amount of solutes. Experiments were conducted at pressure of 1 <span class="hlt">GPa</span> and temperatures from 800 to 900° C using a rocking piston cylinder apparatus. Mantle minerals in equilibrium with COH fluid are represented by synthetic forsterite. fO2 conditions were controlled using the double capsule technique and NNO buffer (ΔFMQ=-0.61 at 800° C; ΔFMQ =-0.98 at 900° C). For the speciation experiments, oxalic acid dihydrate and graphite have been used to generate carbon-saturated COH fluid. The speciation was determined by analyzing the quenched COH fluid, retrieved by piercing the capsule in a gas-tight vessel at T =80° C and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25987700','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25987700"><span>Validation and Development of a Modified Breast Graded Prognostic Assessment As a Tool for Survival in Patients With Breast Cancer and Brain Metastases.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Subbiah, Ishwaria M; Lei, Xiudong; Weinberg, Jeffrey S; Sulman, Erik P; Chavez-MacGregor, Mariana; Tripathy, Debu; Gupta, Rohan; Varma, Ankur; Chouhan, Jay; Guevarra, Richard P; Valero, Vicente; Gilbert, Mark R; Gonzalez-Angulo, Ana M</p> <p>2015-07-10</p> <p>Several indices have been developed to predict overall survival (OS) in patients with breast cancer with brain metastases, including the breast graded prognostic assessment (breast-<span class="hlt">GPA</span>), comprising age, tumor subtype, and Karnofsky performance score. However, number of brain metastases-a highly relevant clinical variable-is less often incorporated into the final model. We sought to validate the existing breast-<span class="hlt">GPA</span> in an independent larger cohort and refine it integrating number of brain metastases. Data were retrospectively gathered from a prospectively maintained institutional database. Patients with newly diagnosed brain metastases from 1996 to 2013 were identified. After validating the breast-<span class="hlt">GPA</span>, multivariable Cox regression and recursive partitioning <span class="hlt">analysis</span> led to the development of the modified breast-<span class="hlt">GPA</span>. The performances of the breast-<span class="hlt">GPA</span> and modified breast-<span class="hlt">GPA</span> were compared using the concordance index. In our cohort of 1,552 patients, the breast-<span class="hlt">GPA</span> was validated as a prognostic tool for OS (P < .001). In multivariable <span class="hlt">analysis</span> of the breast-<span class="hlt">GPA</span> and number of brain metastases (> three v ≤ three), both were independent predictors of OS. We therefore developed the modified breast-<span class="hlt">GPA</span> integrating a fourth clinical parameter. Recursive partitioning <span class="hlt">analysis</span> reinforced the prognostic significance of these four factors. Concordance indices were 0.78 (95% CI, 0.77 to 0.80) and 0.84 (95% CI, 0.83 to 0.85) for the breast-<span class="hlt">GPA</span> and modified breast-<span class="hlt">GPA</span>, respectively (P < .001). The modified breast-<span class="hlt">GPA</span> incorporates four simple clinical parameters of high prognostic significance. This index has an immediate role in the clinic as a formative part of the clinician's discussion of prognosis and direction of care and as a potential patient selection tool for clinical trials. © 2015 by American Society of Clinical Oncology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMMR11C..06K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMMR11C..06K"><span>P - ρ - T data for H2O up to 260 <span class="hlt">GPa</span> under laser-driven shock loading</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kimura, T.; Ozaki, N.; Sano, T.; Okuchi, T.; Shimizu, K.; Miyanishi, K.; Terai, T.; Kakeshita, T.; Sakawa, Y.; Kodama, R.</p> <p>2014-12-01</p> <p>H2O is believed to be one of the most abundant compounds in ice giants including Neptune and Uranus1. Therefore, equation of state (EOS) for H2O is critical for understanding the formation and evolution of these planets. Various EOS models have been suggested for modeling the interior structure of the ice giants2-4. The recent shock experiments reported that their P - ρ data of H2O are in agreement with those of the QMD based EOS model5, indicating that this model is most suitable for modeling H2O in the ice giants. Whether H2O is in the solid or liquid state in the planetary interior has a great importance to understand their internal structures6. While the QMD model predicted that the solid H2O is present in deep interior of their planets above ~100 <span class="hlt">GPa</span>4, the recent measurements revealed that H2O remains in the liquid state even at the deep interior conditions7. This discrepancy between experimental and theoretical studies suggests that the QMD based EOS model is disputable for modeling the planetary interior. Indeed, the comparison between data obtained from the shock experiments and the QMD based EOS did not cover the temperature5. We have obtained P - ρ - T data for H2O up to 260 <span class="hlt">GPa</span> by using laser-driven shock compression technique. The diamond cell applied for the laser shock experiments was used as the sample container in order to achieve temperature conditions lower than the principal Hugoniot states. This shock technique combined with the cell can be used for an assessment the EOS models because it is possible to compare the states under the conditions that the contrast between the models clearly appears. Our data covering P - ρ - T on both the principal and the off Hugoniot curves agree with those of the QMD model, indicating this model to be adopted as the standard for modeling the interior structures of Neptune, Uranus, and exoplanets. References 1W. B. Hubbard et al., The interior of Neptune: Neptune and Triton(Univ. Arizona Press, Tucson, 1995) p</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018CoMP..173...42T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018CoMP..173...42T"><span>Experimental study of quartz inclusions in garnet at pressures up to 3.0 <span class="hlt">GPa</span>: evaluating validity of the quartz-in-garnet inclusion elastic thermobarometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomas, Jay B.; Spear, Frank S.</p> <p>2018-05-01</p> <p>Garnet crystals with quartz inclusions were hydrothermally crystallized from oxide starting materials in piston-cylinder apparatuses at pressures from 0.5 to 3 <span class="hlt">GPa</span> and temperatures ranging from 700 to 800 °C to study how entrapment conditions affect remnant pressures of quartz inclusions used for quartz-in-garnet (QuiG) elastic thermobarometry. Systematic changes of the 128, 206 and 464 cm-1 Raman band frequencies of quartz were used to determine pressures of quartz inclusions in garnet using Raman spectroscopy calibrations that describe the P-T dependencies of Raman band shifts for quartz under hydrostatic pressure. Within analytical uncertainties, inclusion pressures calculated for each of the three Raman band frequencies are equivalent, which suggests that non-hydrostatic stress effects caused by elastic anisotropy in quartz are smaller than measurement errors. The experimental quartz inclusions have pressures ranging from - 0.351 to 1.247 <span class="hlt">GPa</span> that span the range of values observed for quartz inclusions in garnets from natural rocks. Quartz inclusion pressures were used to model P-T conditions at which the inclusions could have been trapped. The accuracy of QuiG thermobarometry was evaluated by considering the differences between pressures measured during experiments and pressures calculated using published equation of state parameters for quartz and garnet. Our experimental results demonstrate that Raman measurements performed at room temperature can be used without corrections to estimate garnet crystallization pressures. Calculated entrapment pressures for quartz inclusions in garnet are less than 10% different from pressures measured during the experiments. Because the method is simple to apply with reasonable accuracy, we expect widespread usage of QuiG thermobarometry to estimate crystallization conditions for garnet-bearing silicic rocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMMR62B1072H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMMR62B1072H"><span>Elastic wave velocities of iron-bearing Ringwoodite (Mg0.8Fe0.2)2SiO2 to 12<span class="hlt">GPa</span> at room temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Higo, Y.; Li, B.; Inoue, T.; Irifune, T.; Libermann, R. C.</p> <p>2002-12-01</p> <p>At present, it is widely accepted that olivine is the most important mineral in the Earth's upper mantle. The elastic property changes associated with the phase transformations to its high-pressure polymorphs are very important parameters to constrain the composition of the mantle transition zone. In this study, we measured the elastic wave velocity of iron-bearing Ringwoodite (Mg0.8Fe0.2)2SiO4. The specimen was hot-pressed at 18<span class="hlt">GPa</span> and 1273K in a 2000-ton Uniaxial Split Sphere Apparatus (ORANGE-2000: GRC at ehime university). The recovered polycrystalline specimen was characterized by x-ray diffraction, EPMA, ultrasonic techniques, and the density was determined by Archimedes' method, and found to be single-phase and fine-grained. Bench top measurements of the compressional and shear wave velocities yielded Vp=9.10 km/s and Vs=5.52 km/s. High-pressure ultrasonic measurement was carried out in a 1000-ton Uniaxial Split-Cylinder Apparatus (USCA-1000: SUNY) at pressures up to 12<span class="hlt">GPa</span> at room temperature using ZnTe as internal pressure marker. The sample was surrounded by lead to minimize the deviatoric stress. Also in this experiment, the travel times of the Al2O3 buffer rod were used for pressure calculation. The travel times of the buffer rod under the same cell geometry have been calibrated as a function of sample pressure by the thermal equation of state of NaCl using in-situ X-ray diffraction techniques. The results of our high-pressure experiment, including the elastic moduli and their pressure dependence, effect of iron on the elastic moduli, as well as their implication for the mantle transition zone, will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22581436-refractive-index-compressibility-lialsi-sub-sub-glass-pressure-range-up-gpa','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22581436-refractive-index-compressibility-lialsi-sub-sub-glass-pressure-range-up-gpa"><span>Refractive index and compressibility of LiAlSi{sub 3}O{sub 8} glass in the pressure range up to 6.0 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kuryaeva, R.G., E-mail: rufina@igm.nsc.ru; Dmitrieva, N.V.; Surkov, N.V.</p> <p>2016-02-15</p> <p>Highlights: • Refractive index and the compressibility of LiAlSi{sub 3}O{sub 8} glass are obtained. • Among Li(Na,K)AlSi{sub 3}O{sub 8} glasses LiAlSi{sub 3}O{sub 8} glass has the lowest compressibility. • Degree of depolymerization (NBO/T = 0.31) for LiAlSi{sub 3}O{sub 8} glass was calculated. • NBO/T = 0.31 indicates a high content of NBOs atoms and Al in LiAlSi{sub 3}O{sub 8} glass. • Proposed reaction corresponds to the condition of the existence of ∼9% Al. - Abstract: The refractive index and the relative changes in the density for LiAlSi{sub 3}O{sub 8} glass in the pressure range up to 6.0 <span class="hlt">GPa</span> were obtainedmore » using a polarization-interference microscope and an apparatus with diamond anvils. The results were compared with the previous data for the NaAlSi{sub 3}O{sub 8} and KAlSi{sub 3}O{sub 8} glasses. The compressibility of glasses increases in a series of alkali metal cations Li{sup +}, Na{sup +}, K{sup +}. From the previously found dependence of the compressibility (at P = 4.0 <span class="hlt">GPa</span>) on the degree of depolymerization the value of NBO/T = 0.31 for LiAlSi{sub 3}O{sub 8} glass was calculated. A high degree of depolymerization of the LiAlSi{sub 3}O{sub 8} glass indicates not only a high content of NBOs atoms in the structural network, but also the presence of highly coordinated aluminum (according to the literature data ∼9%). The proposed schematic reaction for the formation of different structural groups corresponds to the condition of the existence of 9% highly coordinated aluminum.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MeScT..29d5201Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MeScT..29d5201Z"><span>3D geometric phase <span class="hlt">analysis</span> and its application in 3D microscopic morphology measurement</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Ronghua; Shi, Wenxiong; Cao, Quankun; Liu, Zhanwei; Guo, Baoqiao; Xie, Huimin</p> <p>2018-04-01</p> <p>Although three-dimensional (3D) morphology measurement has been widely applied on the macro-scale, there is still a lack of 3D measurement technology on the microscopic scale. In this paper, a microscopic 3D measurement technique based on the 3D-geometric phase <span class="hlt">analysis</span> (<span class="hlt">GPA</span>) method is proposed. In this method, with machine vision and phase matching, the traditional <span class="hlt">GPA</span> method is extended to three dimensions. Using this method, 3D deformation measurement on the micro-scale can be realized using a light microscope. Simulation experiments were conducted in this study, and the results demonstrate that the proposed method has a good anti-noise ability. In addition, the 3D morphology of the necking zone in a tensile specimen was measured, and the results demonstrate that this method is feasible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29233401','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29233401"><span>An <span class="hlt">analysis</span> of the use of Pharmacy Curriculum Outcomes Assessment (PCOA) scores within one professional program.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Garavalia, Linda S; Prabhu, Sunil; Chung, Eunice; Robinson, Daniel C</p> <p></p> <p>The Pharmacy Curriculum Outcomes Assessment (PCOA) is a recent assessment requirement for US pharmacy professional programs. This study analyses PCOA scores for uses described in the 2016 Standards with data from one professional program. PCOA data were analyzed for two consecutive classes (n=215) of pharmacy students at the end of their didactic curriculum to explore relationships among PCOA scores, grade point average (<span class="hlt">GPA</span>), and North American Pharmacist Licensure Examination (NAPLEX) scores utilizing regression analyses. Decisions about student learning based on PCOA scores and <span class="hlt">GPA</span> indicated remediation would have been prescribed for approximately 7% of students. In comparison, NAPLEX scores revealed a 1% failure rate among the study sample. Relationships between PCOA scores and <span class="hlt">GPA</span> (r=0.47) and NAPLEX (r=0.51) were moderate to large, respectively. <span class="hlt">GPA</span> explained a larger portion of unique variance (14%) than PCOA (8%) in NAPLEX scores. In this sample of students, academic decisions would have varied depending upon the learning assessment, which is consistent with a moderate correlation between <span class="hlt">GPA</span> and PCOA scores. Although PCOA scores correlate with <span class="hlt">GPA</span> and NAPLEX, PCOA scores explained a smaller portion of unique variance in NAPLEX scores than <span class="hlt">GPA</span>. The ongoing establishment of validity evidence of PCOA scores is important for meaningful interpretation of scores for the intended uses. Copyright © 2017 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=singularities&pg=7&id=EJ108437','ERIC'); return false;" href="https://eric.ed.gov/?q=singularities&pg=7&id=EJ108437"><span>On Browne's Solution for Oblique <span class="hlt">Procrustes</span> Rotation</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Cramer, Elliot M.</p> <p>1974-01-01</p> <p>A form of Browne's (1967) solution of finding a least squares fit to a specified factor structure is given which does not involve solution of an eigenvalue problem. It suggests the possible existence of a singularity, and a simple modification of Browne's computational procedure is proposed. (Author/RC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PEPS....4...34N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PEPS....4...34N"><span>Melting phase relations in the MgSiO3-CaSiO3 system at 24 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nomura, Ryuichi; Zhou, Youmo; Irifune, Tetsuo</p> <p>2017-12-01</p> <p>The Earth's lower mantle is composed of bridgmanite, ferropericlase, and CaSiO3-rich perovskite. The melting phase relations between each component are key to understanding the melting of the Earth's lower mantle and the crystallization of the deep magma ocean. In this study, melting phase relations in the MgSiO3-CaSiO3 system were investigated at 24 <span class="hlt">GPa</span> using a multi-anvil apparatus. The eutectic composition is (Mg,Ca)SiO3 with 81-86 mol% MgSiO3. The solidus temperature is 2600-2620 K. The solubility of CaSiO3 component into bridgmanite increases with temperature, reaching a maximum of 3-6 mol% at the solidus, and then decreases with temperature. The same trend was observed for the solubility of MgSiO3 component into CaSiO3-rich perovskite, with a maximum of 14-16 mol% at the solidus. The asymmetric regular solutions between bridgmanite and CaSiO3-rich perovskite and between MgSiO3 and CaSiO3 liquid components well reproduce the melting phase relations constrained experimentally. [Figure not available: see fulltext.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19..233S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19..233S"><span>Titanium-bearing phases in the Earth's mantle (evidence from experiments in the MgO-SiO2-TiO2 ±Al2O3 system at 10-24 <span class="hlt">GPa</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sirotkina, Ekaterina; Bobrov, Andrey; Bindi, Luca; Irifune, Tetsuo</p> <p>2017-04-01</p> <p>Introduction Despite significant interest of experimentalists to the study of geophysically important phase equilibria in the Earth's mantle and a huge experimental database on a number of the model and multicomponent systems, incorporation of minor elements in mantle phases was mostly studied on a qualitative level. The influence of such elements on structural peculiarities of high-pressure phases is poorly investigated, although incorporation of even small portions of them may have a certain impact on the PT-parameters of phase transformations. Titanium is one of such elements with the low bulk concentrations in the Earth's mantle (0.2 wt % TiO2) [1]; however, Ti-rich lithologies may occur in the mantle as a result of oceanic crust subduction. Thus, the titanium content is 0.6 wt% in Global Oceanic Subducted Sediments (GLOSS) [2], and 1.5 wt% TiO2, in MORB [3]. In this regard, accumulation of titanium in the Earth's mantle is related to crust-mantle interaction during the subduction of crustal material at different depths of the mantle. Experimental methods At 10-24 <span class="hlt">GPa</span> and 1600°C, we studied the full range of the starting materials in the MgSiO3 (En) - MgTiO3 (Gkl) system in increments of 10-20 mol% Gkl and 1-3 <span class="hlt">GPa</span>, which allowed us to plot the phase PX diagram for the system MgSiO3-MgTiO3 and synthesize titanium-bearing phases with a wide compositional range. The experiments were performed using a 2000-t Kawai-type multi-anvil high-pressure apparatus at the Geodynamics Research Center, Ehime University (Japan). The quenched samples were examined by single-crystal X-ray diffractometer, and the composition of phases was analyzed using SEM-EDS. Results The main phases obtained in experiments were rutile, wadsleyite, MgSiO3-enstatite, MgTiO3-ilmenite, MgTiSi2O7 with the weberite structure type (Web), Mg(Si,Ti)O3 and MgSiO3 with perovskite-type structure. At a pressure of 13 <span class="hlt">GPa</span> for Ti-poor bulk compositions, an association of En+Wad+Rt is replaced by the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMMR23B2662A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMMR23B2662A"><span><em>In Situ</em> X-ray Diffraction of Forsterite Under Shock Compression to 52 <span class="hlt">GPa</span>: Time Resolved Observation of Changes in Crystal Structure and Phase</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akin, M. C.; Maddox, B.; Teruya, A.; Asimow, P. D.</p> <p>2015-12-01</p> <p>The Earth's mantle is composed primarily of ferromagnesian silicates, of which Forsterite (Fo) is the magnesium-rich end member of the dominant upper mantle phase, olivine. Fo is thought to undergo a chemical decomposition associated with a structural phase transition when dynamically loaded to 40-71 <span class="hlt">GPa</span>, but previous inferences about such decomposition have been based only on pressure-density data with no direct phase identification. To obtain direct data on the phase evolution of shocked Fo, synthetic single crystal samples of Mg2SiO4 Fo were loaded to pressures of 52 <span class="hlt">GPa</span> using a two stage light gas gun. X-ray diffraction (XRD) patterns were collected on the static and the loaded samples in situ using a single pulse Mo Kα anode to provide a 17 keV X-ray source. X-ray polycapillary optics were used to couple the source to the sample. Clear Laue spots were observed in the static images, while the dynamic images show the appearance of new spots at early times and powder-like rings at late times. The angles of the dynamically driven spots and rings overlap with each other and indicate the change in phase of forsterite under pressure through a process that begins with the formation of single crystals and ends with polycrystalline material. Efforts are underway to identify the high-pressure phases from among the library of dense magnesium silicates, and further experiments covering a larger pressure range will be completed shortly. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018DokES.479..404S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018DokES.479..404S"><span>Synthesis of NH4-Substituted Muscovite at 6.3 <span class="hlt">GPa</span> and 1000°C: Implications for Nitrogen Transport to the Earth's Mantle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sokol, A. G.; Sokol, E. V.; Kupriyanov, I. N.; Sobolev, N. V.</p> <p>2018-03-01</p> <p>The synthesis of NH4-bearing muscovite at P = 6.3 <span class="hlt">GPa</span> and T = 1000°C in equilibrium with NH3-H2O fluid is performed. It is determined that the newly formed muscovite is enriched in celadonite minal and contains 370 ppm of NH4. The obtained data make it possible to conclude that ammonium-bearing micas have sufficient thermal stability and can transport crustal nitrogen to the mantle in the presence of a reduced water-ammonia fluid at fO2 less than the values of IW + 2 log units even in the regime of "hot" subduction. The key parameter that determines the efficiency of this mechanism for the deep nitrogen cycle is redox stability of NH4-bearing muscovite at the mantle PT-parameters.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006HMR....60...18L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006HMR....60...18L"><span>Discrimination of snipefish Macroramphosus species and boarfish Capros aper morphotypes through multivariate <span class="hlt">analysis</span> of body shape</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lopes, Marta; Murta, Alberto G.; Cabral, Henrique N.</p> <p>2006-03-01</p> <p>The existence of two species of the genus Macroramphosus Lacepède 1803, has been discussed based on morphometric characters, diet composition and depth distribution. Another species, the boarfish Capros aper (Linnaeus 1758), caugth along the Portuguese coast, shows two different morphotypes, one type with smaller eyes and a deeper body than the other, occurring with intermediate forms. In both snipefish and boarfish no sexual dimorphism was found with respect to shape and length relationships. However, females in both genera were on average bigger than males. A multidimensional scaling <span class="hlt">analysis</span> was performed using <span class="hlt">Procrustes</span> distances, in order to check if shape geometry was effective in distinguishing the species of snipefish as well as the morphotypes of boarfish. A multivariate discriminant <span class="hlt">analysis</span> using morphometric characters of snipefish and boarfish was carried out to validate the visual criteria for a distinction of species and morphotypes, respectively. Morphometric characters revealed a great discriminatory power to distinguish morphotypes. Both snipefish and boarfish are very abundant in Portuguese waters, showing two well-defined morphologies and intermediate forms. This study suggests that there may be two different species in each genus and that further studies on these fish should be carried out to investigate if there is reproductive isolation between the morphotypes of boarfish and to validate the species of snipefish.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26429457','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26429457"><span>Image <span class="hlt">analysis</span> of speckle patterns as a probe of melting transitions in laser-heated diamond anvil cell experiments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Salem, Ran; Matityahu, Shlomi; Melchior, Aviva; Nikolaevsky, Mark; Noked, Ori; Sterer, Eran</p> <p>2015-09-01</p> <p>The precision of melting curve measurements using laser-heated diamond anvil cell (LHDAC) is largely limited by the correct and reliable determination of the onset of melting. We present a novel image <span class="hlt">analysis</span> of speckle interference patterns in the LHDAC as a way to define quantitative measures which enable an objective determination of the melting transition. Combined with our low-temperature customized IR pyrometer, designed for measurements down to 500 K, our setup allows studying the melting curve of materials with low melting temperatures, with relatively high precision. As an application, the melting curve of Te was measured up to 35 <span class="hlt">GPa</span>. The results are found to be in good agreement with previous data obtained at pressures up to 10 <span class="hlt">GPa</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23706694','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23706694"><span>Effect of the crown design and interface lute parameters on the stress-state of a machined crown-tooth system: a finite element <span class="hlt">analysis</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shahrbaf, Shirin; vanNoort, Richard; Mirzakouchaki, Behnam; Ghassemieh, Elaheh; Martin, Nicolas</p> <p>2013-08-01</p> <p>The effect of preparation design and the physical properties of the interface lute on the restored machined ceramic crown-tooth complex are poorly understood. The aim of this work was to determine, by means of three-dimensional finite element <span class="hlt">analysis</span> (3D FEA) the effect of the tooth preparation design and the elastic modulus of the cement on the stress state of the cemented machined ceramic crown-tooth complex. The three-dimensional structure of human premolar teeth, restored with adhesively cemented machined ceramic crowns, was digitized with a micro-CT scanner. An accurate, high resolution, digital replica model of a restored tooth was created. Two preparation designs, with different occlusal morphologies, were modeled with cements of 3 different elastic moduli. Interactive medical image processing software (mimics and professional CAD modeling software) was used to create sophisticated digital models that included the supporting structures; periodontal ligament and alveolar bone. The generated models were imported into an FEA software program (hypermesh version 10.0, Altair Engineering Inc.) with all degrees of freedom constrained at the outer surface of the supporting cortical bone of the crown-tooth complex. Five different elastic moduli values were given to the adhesive cement interface 1.8<span class="hlt">GPa</span>, 4<span class="hlt">GPa</span>, 8<span class="hlt">GPa</span>, 18.3<span class="hlt">GPa</span> and 40<span class="hlt">GPa</span>; the four lower values are representative of currently used cementing lutes and 40<span class="hlt">GPa</span> is set as an extreme high value. The stress distribution under simulated applied loads was determined. The preparation design demonstrated an effect on the stress state of the restored tooth system. The cement elastic modulus affected the stress state in the cement and dentin structures but not in the crown, the pulp, the periodontal ligament or the cancellous and cortical bone. The results of this study suggest that both the choice of the preparation design and the cement elastic modulus can affect the stress state within the restored crown</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29334967','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29334967"><span>Risk factors and treatment of pneumothorax secondary to granulomatosis with polyangiitis: a clinical <span class="hlt">analysis</span> of 25 cases.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shi, Xuhua; Zhang, Yongfeng; Lu, Yuewu</p> <p>2018-01-15</p> <p>To investigate the risk factors and treatment strategies for pneumothorax secondary to granulomatosis with polyangiitis (<span class="hlt">GPA</span>). Retrospective <span class="hlt">analysis</span> of cases with pneumothorax secondary to <span class="hlt">GPA</span> from our own practice and published on literature. A total of 25 patients, 18 males and 7 females, mean age 44 ± 15.7 years, were analyzed. Diagnosis included pneumothorax (11 cases), hydropneumothorax (n = 5), empyema (n = 8) and hemopneumothorax (n = 1). 88% (22/25) patients showed single/multiple pulmonary/ subpleural nodules with/without cavitation on chest imaging. Erythrocyte sedimentation rate and C-reactive protein were both elevated. Corticosteroids and immunosuppressive agents were used in 16 cases. Five cases received steroid pulse therapy, of which 4 patients survived. Pleural drainage was effective in some patients. Seven patients underwent surgical operations. In the 10 fatal cases, infection and respiratory failure were the most common cause. Lung biopsy/ autopsy showed lung/pleural necrotizing granulomatous vasculitis, breaking into the chest cavity, pleural fibrosis, bronchial pleural fistula, etc. The mean age in the death group was greater than the survival group (53 ± 12.9 years vs 40.1 ± 14.7 years, p = 0.05), the ineffective pleural drainage was also higher in the death group (5/5 vs 0/7, p = 0.01). Pneumothorax was seen in the active <span class="hlt">GPA</span>, due to a variety of reasons, and gave rise to high fatality rate. Aggressive treatment of <span class="hlt">GPA</span> can improve the prognosis. Older and lack of response for pleural drainage indicates poor prognosis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V51A2746S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V51A2746S"><span>Textural changes of FER-A peridotite in time series piston-cylinder experiments at 1.0 <span class="hlt">GPa</span>, 1300°C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schwab, B. E.; Mercer, C. N.; Johnston, A.</p> <p>2012-12-01</p> <p>A series of eight 1.0 <span class="hlt">GPa</span>, 1300°C partial melting experiments were performed using FER-A peridotite starting material to investigate potential textural changes in the residual crystalline phases over time. Powdered peridotite with a layer of vitreous carbon spheres as a melt sink were sealed in graphite-lined Pt capsules and run in CaF2 furnace assemblies in 1.27cm piston-cylinder apparatus at the University of Oregon. Run durations ranged from 4 to 128 hours. Experimental charges were mounted in epoxy, cut, and polished for <span class="hlt">analysis</span>. In a first attempt to quantify the mineral textures, individual 500x BSE images were collected from selected, representative locations on each of the experimental charges using the FEI Quanta 250 ESEM at Humboldt State University. Noran System Seven (NSS) EDS system was used to collect x-ray maps (spectral images) to aid in identification of phases. A combination of image <span class="hlt">analysis</span> techniques within NSS and ImageJ software are being used to process the images and quantify the mineral textures observed. The goals are to quantify the size, shape, and abundance of residual olivine (ol), orthopyroxene (opx), clinopyroxene (cpx), and spinel crystals within the selected sample areas of the run products. Additional work will be done to compare the results of the selected areas with larger (lower magnification) images acquired using the same techniques. Preliminary results indicate that measurements of average grain area, minimum grain area, and average, maximum, and minimum grain perimeter show the greatest change (generally decreasing) in measurements for ol, opx, and cpx between the shortest-duration, 4-hour, experiment and the subsequent, 8-hour, experiment. The largest relative change in nearly all of these measurements appears to be for cpx. After the initial decrease, preliminary measurements remain relatively constant for ol, opx, and cpx, respectively, in experiments from 8 to 128 hours in duration. In contrast, measured parameters</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26PSL.397...80C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26PSL.397...80C"><span>Experimental melting of phlogopite-bearing mantle at 1 <span class="hlt">GPa</span>: Implications for potassic magmatism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Condamine, Pierre; Médard, Etienne</p> <p>2014-07-01</p> <p>We have experimentally investigated the fluid-absent melting of a phlogopite peridotite at 1.0 <span class="hlt">GPa</span> (1000-1300 °C) to understand the source of K2O- and SiO2-rich magmas that occur in continental, post-collisional and island arc settings. Using a new extraction technique specially developed for hydrous conditions combined with iterative sandwich experiments, we have determined the composition of low- to high-degree melts (Φ=1.4 to 24.2 wt.%) of metasomatized lherzolite and harzburgite sources. Due to small amounts of adsorbed water in the starting material, amphibole crystallized at the lowest investigated temperatures. Amphibole breaks down at 1050-1075 °C, while phlogopite-breakdown occurs at 1150-1200 °C. This last temperature is higher than the previously determined in a mantle assemblage, due to the presence of stabilizing F and Ti. Phlogopite-lherzolite melts incongruently according to the continuous reaction: 0.49 phlogopite + 0.56 orthopyroxene + 0.47 clinopyroxene + 0.05 spinel = 0.58 olivine + 1.00 melt. In the phlogopite-harzburgite, the reaction is: 0.70 phlogopite + 1.24 orthopyroxene + 0.05 spinel = 0.99 olivine + 1.00 melt. The K2O content of water-undersaturated melts in equilibrium with residual phlogopite is buffered, depending on the source fertility: from ∼3.9 wt.% in lherzolite to ∼6.7 wt.% in harzburgite. Primary melts are silica-saturated and evolve from trachyte to basaltic andesite (63.5-52.1 wt.% SiO2) with increasing temperature. Calculations indicate that such silica-rich melts can readily be extracted from their mantle source, due to their low viscosity. Our results confirm that potassic, silica-rich magmas described worldwide in post-collisional settings are generated by melting of a metasomatized phlogopite-bearing mantle in the spinel stability field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24334393','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24334393"><span>GeneOnEarth: fitting genetic PC plots on the globe.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Torres-Sánchez, Sergio; Medina-Medina, Nuria; Gignoux, Chris; Abad-Grau, María M; González-Burchard, Esteban</p> <p>2013-01-01</p> <p>Principal component (PC) plots have become widely used to summarize genetic variation of individuals in a sample. The similarity between genetic distance in PC plots and geographical distance has shown to be quite impressive. However, in most situations, individual ancestral origins are not precisely known or they are heterogeneously distributed; hence, they are hardly linked to a geographical area. We have developed GeneOnEarth, a user-friendly web-based tool to help geneticists to understand whether a linear isolation-by-distance model may apply to a genetic data set; thus, genetic distances among a set of individuals resemble geographical distances among their origins. Its main goal is to allow users to first apply a by-view <span class="hlt">Procrustes</span> method to visually learn whether this model holds. To do that, the user can choose the exact geographical area from an on line 2D or 3D world map by using, respectively, Google Maps or Google Earth, and rotate, flip, and resize the images. GeneOnEarth can also compute the optimal rotation angle using <span class="hlt">Procrustes</span> <span class="hlt">analysis</span> and assess statistical evidence of similarity when a different rotation angle has been chosen by the user. An online version of GeneOnEarth is available for testing and using purposes at http://bios.ugr.es/GeneOnEarth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29587647','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29587647"><span>Study of morphological variation of northern Neotropical Ariidae reveals conservatism despite macrohabitat transitions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stange, Madlen; Aguirre-Fernández, Gabriel; Salzburger, Walter; Sánchez-Villagra, Marcelo R</p> <p>2018-03-27</p> <p>Morphological convergence triggered by trophic adaptations is a common pattern in adaptive radiations. The study of shape variation in an evolutionary context is usually restricted to well-studied fish models. We take advantage of the recently revised systematics of New World Ariidae and investigate skull shape evolution in six genera of northern Neotropical Ariidae. They constitute a lineage that diversified in the marine habitat but repeatedly adapted to freshwater habitats. 3D geometric morphometrics was applied for the first time in catfish skulls and phylogenetically informed statistical analyses were performed to test for the impact of habitat on skull diversification after habitat transition in this lineage. We found that skull shape is conserved throughout phylogeny. A morphospace <span class="hlt">analysis</span> revealed that freshwater and marine species occupy extreme ends of the first principal component axis and that they exhibit similar <span class="hlt">Procrustes</span> variances. Yet freshwater species occupy the smallest shape space compared to marine and brackish species (based on partial disparity), and marine and freshwater species have the largest <span class="hlt">Procrustes</span> distance to each other. We observed a single case of shape convergence as derived from 'C-metrics', which cannot be explained by the occupation of the same habitat. Although Ariidae occupy such a broad spectrum of different habitats from sea to freshwater, the morphospace <span class="hlt">analysis</span> and analyses of shape and co-variation with habitat in a phylogenetic context shows that conservatism dominates skull shape evolution among ariid genera.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3729822','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3729822"><span>Geometric morphometric footprint <span class="hlt">analysis</span> of young women</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Background Most published attempts to quantify footprint shape are based on a small number of measurements. We applied geometric morphometric methods to study shape variation of the complete footprint outline in a sample of 83 adult women. Methods The outline of the footprint, including the toes, was represented by a comprehensive set of 85 landmarks and semilandmarks. Shape coordinates were computed by Generalized <span class="hlt">Procrustes</span> <span class="hlt">Analysis</span>. Results The first four principal components represented the major axes of variation in foot morphology: low-arched versus high-arched feet, long and narrow versus short and wide feet, the relative length of the hallux, and the relative length of the forefoot. These shape features varied across the measured individuals without any distinct clusters or discrete types of footprint shape. A high body mass index (BMI) was associated with wide and flat feet, and a high frequency of wearing high-heeled shoes was associated with a larger forefoot area of the footprint and a relatively long hallux. Larger feet had an increased length-to-width ratio of the footprint, a lower-arched foot, and longer toes relative to the remaining foot. Footprint shape differed on average between left and right feet, and the variability of footprint asymmetry increased with BMI. Conclusions Foot shape is affected by lifestyle factors even in a sample of young women (median age 23 years). Geometric morphometrics proved to be a powerful tool for the detailed <span class="hlt">analysis</span> of footprint shape that is applicable in various scientific disciplines, including forensics, orthopedics, and footwear design. PMID:23886074</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23660837','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23660837"><span>Structural determinants at the interface of the ARC2 and leucine-rich repeat domains control the activation of the plant immune receptors Rx1 and <span class="hlt">Gpa</span>2.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Slootweg, Erik J; Spiridon, Laurentiu N; Roosien, Jan; Butterbach, Patrick; Pomp, Rikus; Westerhof, Lotte; Wilbers, Ruud; Bakker, Erin; Bakker, Jaap; Petrescu, Andrei-José; Smant, Geert; Goverse, Aska</p> <p>2013-07-01</p> <p>Many plant and animal immune receptors have a modular nucleotide-binding-leucine-rich repeat (NB-LRR) architecture in which a nucleotide-binding switch domain, NB-ARC, is tethered to a LRR sensor domain. The cooperation between the switch and sensor domains, which regulates the activation of these proteins, is poorly understood. Here, we report structural determinants governing the interaction between the NB-ARC and LRR in the highly homologous plant immune receptors <span class="hlt">Gpa</span>2 and Rx1, which recognize the potato cyst nematode Globodera pallida and Potato virus X, respectively. Systematic shuffling of polymorphic sites between <span class="hlt">Gpa</span>2 and Rx1 showed that a minimal region in the ARC2 and N-terminal repeats of the LRR domain coordinate the activation state of the protein. We identified two closely spaced amino acid residues in this region of the ARC2 (positions 401 and 403) that distinguish between autoactivation and effector-triggered activation. Furthermore, a highly acidic loop region in the ARC2 domain and basic patches in the N-terminal end of the LRR domain were demonstrated to be required for the physical interaction between the ARC2 and LRR. The NB-ARC and LRR domains dissociate upon effector-dependent activation, and the complementary-charged regions are predicted to mediate a fast reassociation, enabling multiple rounds of activation. Finally, we present a mechanistic model showing how the ARC2, NB, and N-terminal half of the LRR form a clamp, which regulates the dissociation and reassociation of the switch and sensor domains in NB-LRR proteins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910071420&hterms=ahrens&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dahrens','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910071420&hterms=ahrens&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dahrens"><span>Shock wave equation of state of serpentine to 150 <span class="hlt">GPa</span> - Implications for the occurrence of water in the earth's lower mantle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tyburczy, James A.; Duffy, Thomas S.; Ahrens, Thomas J.; Lange, Manfred A.</p> <p>1991-01-01</p> <p>The shock wave equation of state of Mg end-member serpentine was determined to 150 <span class="hlt">GPa</span> by examining the shock properties of three polycrystalline serpentines: (1) a lizardite serpentine found near Globe (Arizona), (2) an antigorite serpentine from Thurman (New York), and (3) a chrysotile serpentine from Quebec (Canada). The shock wave experiments were carried out using either a two-stage light gas gun or a 40-mm bore propellant. The shock equation of state that was obtained is shown to exhibit four distinct regions: a low-pressure phase, a mixed phase region, a high-pressure phase, and a very high-pressure phase. The high-pressure density and sound speed of an H2O-rich magnesium silicate determined from these experiments indicate that the observed seismic properties of the lower mantle allow the existence of several weight percent of water in the lower mantle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JEMat..35.2107X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JEMat..35.2107X"><span>Nanoindentation on SnAgCu lead-free solder joints and <span class="hlt">analysis</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Luhua; Pang, John H. L.</p> <p>2006-12-01</p> <p>The lead-free SnAgCu (SAC) solder joint on copper pad with organic solderability preservative (Cu-OSP) and electroless nickel and immersion gold (ENIG) subjected to thermal testing leads to intermetallic growth. It causes corresponding reliability concerns at the interface. Nanoindentation characterization on SnAgCu solder alloy, intermetallic compounds (IMCs), and the substrates subjected to thermal aging is reported. The modulus and hardness of thin IMC layers were measured by nanoindentation continuous stiffness measurement (CSM) from planar IMC surface. When SAC/Ni(Au) solder joints were subject to thermal aging, the Young’s modulus of the NiCuSn IMC at the SAC/ENIG specimen changed from 207 <span class="hlt">GPa</span> to 146 <span class="hlt">GPa</span> with different aging times up to 500 h. The hardness decreased from 10.0 <span class="hlt">GPa</span> to 7.3 <span class="hlt">GPa</span>. For the SAC/Cu-OSP reaction couple, the Young’s modulus of Cu6Sn5 stayed constant at 97.0 <span class="hlt">GPa</span> and hardness about 5.7 <span class="hlt">GPa</span>. Electron-probe microanalysis (EPMA) was used to thermal aging. The creep effect on the measured result was analyzed when measuring SnAgCu solder; it was found that the indentation penetration, and thus the hardness, is loading rate dependent. With the proposed constant P/P experiment, a constant indentation strain rate h/h and hardness could be achieved. The log-log plot of indentation strain rate versus hardness for the data from the constant P/P experiments yields a slope of 7.52. With the optimized test method and CSM Technique, the Modulus of SAC387 solder alloy and all the layers in a solder joint were investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGP31A1282B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGP31A1282B"><span>Discrimination of Thermal versus Mechanical Effects of Shock on Rock Magnetic Properties of Spherically Shocked up to 10-160 <span class="hlt">GPa</span> Basalt and Diabase</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bezaeva, N. S.; Swanson-Hysell, N.; Tikoo, S.; Badyukov, D. D.; Kars, M. A. C.; Egli, R.; Chareev, D. A.; Fairchild, L. M.</p> <p>2016-12-01</p> <p>Understanding how shock waves generated during hypervelocity impacts affect rock magnetic properties is key for interpreting the paleomagnetic records of lunar rocks, meteorites, and cratered planetary surfaces. Laboratory simulations of impacts show that ultra-high shocks may induce substantial post-shock heating of the target material. At high pressures (>10 <span class="hlt">GPa</span>), shock heating occurs in tandem with mechanical effects, such as grain fracturing and creation of crystallographic defects and dislocations within magnetic grains. This makes it difficult to conclude whether shock-induced changes in the rock magnetic properties of target materials are primarily associated with mechanical or thermal effects. Here we present novel experimental methods to discriminate between mechanical and thermal effects of shock on magnetic properties and illustrate it with two examples of spherically shocked terrestrial basalt and diabase [1], which were shocked to pressures of 10 to >160 <span class="hlt">GPa</span>, and investigate possible explanations for the observed shock-induced magnetic hardening (i.e., increase in remanent coercivity Bcr). The methods consist of i) conducting extra heating experiments at temperatures resembling those experienced during high-pressure shock events on untreated equivalents of shocked rocks (with further comparison of Bcr of shocked and heated samples) and ii) quantitative comparison of high-resolution first-order reversal curve (FORC) diagrams (field step: 0.5-0.7 mT) for shocked, heated and untreated specimens. Using this approach, we demonstrated that the shock-induced coercivity hardening in our samples is predominantly due to solid-state, mechanical effects of shock rather than alteration associated with shock heating. Indeed, heating-induced changes in Bcr in the post-shock temperature range were minor. Visual inspection of FORC contours (in addition to detailed analyses) reveals a stretching of the FORC distribution of shocked sample towards higher coercivities</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26187415','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26187415"><span>Impact of Study Skills and Parent Education on First-Year <span class="hlt">GPA</span> Among College Students With and Without ADHD: A Moderated Mediation Model.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gormley, Matthew J; Pinho, Trevor; Pollack, Brittany; Puzino, Kristina; Franklin, Melanie K; Busch, Chelsea; DuPaul, George J; Weyandt, Lisa L; Anastopoulos, Arthur D</p> <p>2018-02-01</p> <p>To test if the relationship between ADHD and academic achievement is mediated by service utilization and/or study skills, and if these mediation effects are moderated by parental education level. A bootstrapping method within structural equation modeling was used with data from 355 first year college students meeting strict criteria for ADHD or clearly without ADHD to test the mediation and moderation effects. Study skills, but not service utilization, significantly mediated the relationship between ADHD status and <span class="hlt">GPA</span>; however, this relationship was not significant among students with at least one parent holding a master's degree or higher. Among first year college students study skills may be a more salient predictor of educational outcomes relative to ADHD status. Additional research into support services for college students with ADHD is needed, however, results suggest interventions targeting study skills may hold particular promise for these students.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930000975','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930000975"><span>Phase transformations in 40-60-<span class="hlt">GPa</span> shocked gneisses from the Haughton Crater (Canada): An Analytical Transmission Electron Microscopy (ATEM) study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Martinez, I.; Guyot, F.; Schaerer, U.</p> <p>1992-01-01</p> <p>In order to better understand phase transformations, chemical migration, and isotopic disequilibrium in highly shocked rocks, we have performed a microprobe and an ATEM study on gneisses shocked up to 60 <span class="hlt">GPa</span> from the Haughton Crater. This study reveals the following chemical and structural characteristics: (1) SiO2 dominant areas are formed by a mixture of pure SiO2 polycrystalline quartz identified by electron diffraction pattern and chemical <span class="hlt">analysis</span> and a silica-rich amorphous phase containing minor amounts of aluminium, potassium, and iron; (2) Areas with biotitelike composition are formed by less than 200-nm grains of iron-rich spinels embedded in a silica-rich amorphous phase that is very similar to the one described above; (3) Layers with feldsparlike composition are constituted by 100-200-nm-sized alumina-rich grains (the indexation of the crystalline structure is under progress) and the silica-rich amorphous phase; (4) Zones characterized by the unusual Al/Si ratio close to 1 are formed by spinel grains (200-nm-sized) embedded in the same silica-rich amorphous phase; and (5) The fracturated sillimanites contain domains with a lamellar structure, defined by the intercalation of 100-nm-wide lamellae of mullite crystals and of a silica-rich amorphous phase. These mullite crystals preserved the crystallographical orientation of the preshock sillimanite. All compositional domains, identified at the microprobe scale, can thus be explained by a mixture in different proportion between the following phases: (1) a silica-rich amorphous phase, with minor Al and K; (2) quartz crystals; (3) spinel crystals and alumina-rich crystals; (4) sillimanite; and (5) mullite. Such mixtures of amorphous phases and crystals in different proportions explain disturbed isotope systems in these rocks and chemical heterogeneities observed on the microprobe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1111067.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1111067.pdf"><span>An <span class="hlt">Analysis</span> of Teacher Candidate Success as Measured by Admission Requirements</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Texas, Araceli Garza; Mundy, Marie-Anne; Varela, Daniella; Ybarra, Anissa; Yuma, Stephanie</p> <p>2016-01-01</p> <p>There has been little to no data indicating that candidate scores on the Nelson Denny Reading Assessment, entrance <span class="hlt">GPA</span>, and basic skills were effective measures for success in educator preparation programs. This study contributed to the body of knowledge by evaluating whether candidate scores on the Nelson Denny Reading Assessment, entrance <span class="hlt">GPA</span>,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010GeCoA..74.6852S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GeCoA..74.6852S"><span>Ammonium in aqueous fluids to 600 °C, 1.3 <span class="hlt">GPa</span>: A spectroscopic study on the effects on fluid properties, silica solubility, and K-feldspar to muscovite reactions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmidt, Christian; Watenphul, Anke</p> <p>2010-12-01</p> <p>The behavior of ammonium, NH 4+, in aqueous systems was studied based on Raman spectroscopic experiments to 600 °C and about 1.3 <span class="hlt">GPa</span>. Spectra obtained at ambient conditions revealed a strong reduction of the dynamic three-dimensional network of water with addition of ammonium chloride, particularly at small solute concentrations. The differential scattering cross section of the ν 1-NH 4+ Raman band in these solutions was found to be similar to that of salammoniac. The Raman band of silica monomers at ˜780 cm -1 was present in all spectra of the fluid at high temperatures in hydrothermal diamond-anvil cell experiments with H 2O ± NH 4Cl and quartz or the assemblage quartz + kyanite + K-feldspar ± muscovite/tobelite. However, these spectra indicated that dissolved silica is less polymerized in ammonium chloride solutions than in comparable experiments with water. Quantification based on the normalized integrated intensity of the H 4SiO 40 band showed that the silica solubility in experiments with H 2O + NH 4Cl was significantly lower than that in equimolal NaCl solutions. This suggests that ammonium causes a stronger decrease in the activity of water in chloridic solutions than sodium. The Raman spectra of the fluid also showed that a significant fraction of ammonium was converted to ammonia, NH 3, in all experiments at temperatures above 300 °C. This indicates a shift towards acidic conditions for experiments without a buffering mineral assemblage. The estimated pH of the fluid was ˜2 at 600 °C, 0.26 <span class="hlt">GPa</span>, 6.6 m initial NH 4Cl, based on the ratio of the integrated ν 1-NH 3 and ν 1-NH 4+ intensities and the HCl 0 dissociation constant. The NH 3/NH 4+ ratio increased with temperature and decreased with pressure. This implies that more ammonium should be retained in K-bearing minerals coexisting with chloridic fluids upon high- P low- T metamorphism. At 500 °C, 0.73 <span class="hlt">GPa</span>, ammonium partitions preferentially into the fluid, as constrained from infrared</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ThApC.111..649A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ThApC.111..649A"><span>An <span class="hlt">analysis</span> of annual maximum streamflows in Terengganu, Malaysia using TL-moments approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahmad, Ummi Nadiah; Shabri, Ani; Zakaria, Zahrahtul Amani</p> <p>2013-02-01</p> <p>TL-moments approach has been used in an <span class="hlt">analysis</span> to determine the best-fitting distributions to represent the annual series of maximum streamflow data over 12 stations in Terengganu, Malaysia. The TL-moments with different trimming values are used to estimate the parameter of the selected distributions namely: generalized pareto (<span class="hlt">GPA</span>), generalized logistic, and generalized extreme value distribution. The influence of TL-moments on estimated probability distribution functions are examined by evaluating the relative root mean square error and relative bias of quantile estimates through Monte Carlo simulations. The boxplot is used to show the location of the median and the dispersion of the data, which helps in reaching the decisive conclusions. For most of the cases, the results show that TL-moments with one smallest value was trimmed from the conceptual sample (TL-moments (1,0)), of <span class="hlt">GPA</span> distribution was the most appropriate in majority of the stations for describing the annual maximum streamflow series in Terengganu, Malaysia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012GeCoA..93..164H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012GeCoA..93..164H"><span>Experimental evidence for the absence of iron isotope fractionation between metal and silicate liquids at 1 <span class="hlt">GPa</span> and 1250-1300 °C and its cosmochemical consequences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hin, Remco C.; Schmidt, Max W.; Bourdon, Bernard</p> <p>2012-09-01</p> <p>Iron isotope fractionation during metal-silicate differentiation has been proposed as a cause for differences in iron isotope compositions of chondrites, iron meteorites and the bulk silicate Earth. Stable isotope fractionation, however, rapidly decreases with increasing temperature. We have thus performed liquid metal-liquid silicate equilibration experiments at 1250-1300 °C and 1 <span class="hlt">GPa</span> to address whether Fe isotope fractionation is resolvable at the lowest possible temperatures for magmatic metal-silicate differentiation. A centrifuging piston cylinder apparatus enabled quantitative metal-silicate segregation. Elemental tin or sulphur was used in the synthetic metal-oxide mixtures to lower the melting temperature of the metal. The analyses demonstrate that eight of the 10 experimental systems equilibrated in a closed isotopic system, as was assessed by varying run durations and starting Fe isotope compositions. Statistically significant iron isotope fractionation between quenched metals and silicates was absent in nine of the 10 experiments and all 10 experiments yield an average metal-silicate fractionation factor of 0.01 ± 0.04‰, independent of whether graphite or silica glass capsules were used. This implies that Fe isotopes do not fractionate during low pressure metal-silicate segregation under magmatic conditions. In large bodies such as the Earth, fractionation between metal and high pressure (>20 <span class="hlt">GPa</span>) silicate phases may still be a possible process for equilibrium fractionation during metal-silicate differentiation. However, the 0.07 ± 0.02‰ heavier composition of bulk magmatic iron meteorites relative to the average of bulk ordinary/carbonaceous chondrites cannot result from equilibrium Fe isotope fractionation during core segregation. The up to 0.5‰ lighter sulphide than metal fraction in iron meteorites and in one ordinary chondrite can only be explained by fractionation during subsolidus processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2875674','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2875674"><span>Alteration of Dentin-Enamel Mechanical Properties Due to Dental Whitening Treatments</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zimmerman, B.; Datko, L.; Cupelli, M.; Alapati, S.; Dean, D.; Kennedy, M.</p> <p>2010-01-01</p> <p>The mechanical properties of dentin and enamel affect the reliability and wear properties of a tooth. This study investigated the influence of clinical dental treatments and procedures, such as whitening treatments or etching prior to restorative procedures. Both autoclaved and non-autoclaved teeth were studied in order to allow for both comparison with published values and improved clinical relevance. Nanoindentation <span class="hlt">analysis</span> with the Oliver-Pharr model provided elastic modulus and hardness across the dentin-enamel junction (DEJ). Large increases were observed in the elastic modulus of enamel in teeth that had been autoclaved (52.0<span class="hlt">GPa</span> versus 113.4<span class="hlt">GPa</span>), while smaller increases were observed in the dentin (17.9<span class="hlt">GPa</span> versus 27.9<span class="hlt">GPa</span>). Likewise, there was an increase in the hardness of enamel (2.0<span class="hlt">GPa</span> versus 4.3<span class="hlt">GPa</span>) and dentin (0.5<span class="hlt">GPa</span> versus 0.7<span class="hlt">GPa</span>) with autoclaving. These changes suggested that the range of elastic modulus and hardness values previously reported in literature may be partially due to the sterilization procedures. Treatment of the exterior of non-autoclaved teeth with Crest Whitestrips™, Opalescence™ or UltraEtch™ caused changes in the mechanical properties of both the enamel and dentin. Those treated with Crest Whitestrips™ showed a reduction in the elastic modulus of enamel (55.3<span class="hlt">GPa</span> to 32.7<span class="hlt">GPa</span>) and increase in the elastic modulus of dentin (17.2<span class="hlt">GPa</span> to 24.3<span class="hlt">GPa</span>). Opalescence™ treatments did not significantly affect the enamel properties, but did result in a decrease in modulus of dentin (18.5<span class="hlt">GPa</span> to 15.1<span class="hlt">GPa</span>). Additionally, as expected, UltraEtch™ treatment decreased the modulus and hardness of enamel (48.7<span class="hlt">GPa</span> to 38.0<span class="hlt">GPa</span> and 1.9<span class="hlt">GPa</span> to 1.5<span class="hlt">GPa</span>, respectively) and dentin (21.4<span class="hlt">GPa</span> to 15.0<span class="hlt">GPa</span> and 1.9<span class="hlt">GPa</span> to 1.5<span class="hlt">GPa</span>, respectively). Changes in the mechanical properties were linked to altered protein concentration within the tooth, as evidenced by fluorescence microscopy and Fourier transform infrared spectroscopy. PMID:20346902</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20346902','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20346902"><span>Alteration of dentin-enamel mechanical properties due to dental whitening treatments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zimmerman, B; Datko, L; Cupelli, M; Alapati, S; Dean, D; Kennedy, M</p> <p>2010-05-01</p> <p>The mechanical properties of dentin and enamel affect the reliability and wear properties of a tooth. This study investigated the influence of clinical dental treatments and procedures, such as whitening treatments or etching prior to restorative procedures. Both autoclaved and non-autoclaved teeth were studied in order to allow for both comparison with published values and improved clinical relevance. Nanoindentation <span class="hlt">analysis</span> with the Oliver-Pharr model provided elastic modulus and hardness across the dentin-enamel junction (DEJ). Large increases were observed in the elastic modulus of enamel in teeth that had been autoclaved (52.0 <span class="hlt">GPa</span> versus 113.4 <span class="hlt">GPa</span>), while smaller increases were observed in the dentin (17.9 <span class="hlt">GPa</span> versus 27.9 <span class="hlt">GPa</span>). Likewise, there was an increase in the hardness of enamel (2.0 <span class="hlt">GPa</span> versus 4.3 <span class="hlt">GPa</span>) and dentin (0.5 <span class="hlt">GPa</span> versus 0.7 <span class="hlt">GPa</span>) with autoclaving. These changes suggested that the range of elastic modulus and hardness values previously reported in the literature may be partially due to the sterilization procedures. Treatment of the exterior of non-autoclaved teeth with Crest Whitestrips, Opalescence or UltraEtch caused changes in the mechanical properties of both the enamel and dentin. Those treated with Crest Whitestrips showed a reduction in the elastic modulus of enamel (55.3 <span class="hlt">GPa</span> to 32.7 <span class="hlt">GPa</span>) and increase in the elastic modulus of dentin (17.2 <span class="hlt">GPa</span> to 24.3 <span class="hlt">GPa</span>). Opalescence treatments did not significantly affect the enamel properties, but did result in a decrease in the modulus of dentin (18.5 <span class="hlt">GPa</span> to 15.1 <span class="hlt">GPa</span>). Additionally, as expected, UltraEtch treatment decreased the modulus and hardness of enamel (48.7 <span class="hlt">GPa</span> to 38.0 <span class="hlt">GPa</span> and 1.9 <span class="hlt">GPa</span> to 1.5 <span class="hlt">GPa</span>, respectively) and dentin (21.4 <span class="hlt">GPa</span> to 15.0 <span class="hlt">GPa</span> and 1.9 <span class="hlt">GPa</span> to 1.5 <span class="hlt">GPa</span>, respectively). Changes in the mechanical properties were linked to altered protein concentration within the tooth, as evidenced by fluorescence microscopy and Fourier transform infrared spectroscopy. Published by Elsevier Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.7757C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.7757C"><span>Tracking silica in Earth's upper mantle using new sound velocity data for coesite to 5.8 <span class="hlt">GPa</span> and 1073 K</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Ting; Liebermann, Robert C.; Zou, Yongtao; Li, Ying; Qi, Xintong; Li, Baosheng</p> <p>2017-08-01</p> <p>The compressional and shear wave velocities for coesite have been measured simultaneously up to 5.8 <span class="hlt">GPa</span> and 1073 K by ultrasonic interferometry for the first time. The shear wave velocity decreases with pressure along all isotherms. The resulting contrasts between coesite and stishovite reach 34% and 45% for <fi>P</fi> and <fi>S</fi> wave velocities, respectively, and 64% and 75% for their impedance at mantle conditions. The large velocity and impedance contrasts across coesite-stishovite transition imply that to generate the velocity and impedance contrasts observed at the X-discontinuity, only a small amount of silica would be required. The velocity jump dependences on silica, <fi>d</fi>(ln<fi>V</fi><fi>P</fi>)/<fi>d</fi>(SiO2) = 0.38 (wt %)-1 and <fi>d</fi>(ln<fi>V</fi><fi>S</fi>)/<fi>d</fi>(SiO2) = 0.52 (wt %)-1, are utilized to place constraints on the amount of silica in the upper mantle and provide a geophysical approach to track mantle eclogite materials and ancient subducted oceanic slabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12831212','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12831212"><span>Size and shape measurement in contemporary cephalometrics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McIntyre, Grant T; Mossey, Peter A</p> <p>2003-06-01</p> <p>The traditional method of analysing cephalograms--conventional cephalometric <span class="hlt">analysis</span> (CCA)--involves the calculation of linear distance measurements, angular measurements, area measurements, and ratios. Because shape information cannot be determined from these 'size-based' measurements, an increasing number of studies employ geometric morphometric tools in the cephalometric <span class="hlt">analysis</span> of craniofacial morphology. Most of the discussions surrounding the appropriateness of CCA, <span class="hlt">Procrustes</span> superimposition, Euclidean distance matrix <span class="hlt">analysis</span> (EDMA), thin-plate spline <span class="hlt">analysis</span> (TPS), finite element morphometry (FEM), elliptical Fourier functions (EFF), and medial axis <span class="hlt">analysis</span> (MAA) have centred upon mathematical and statistical arguments. Surprisingly, little information is available to assist the orthodontist in the clinical relevance of each technique. This article evaluates the advantages and limitations of the above methods currently used to analyse the craniofacial morphology on cephalograms and investigates their clinical relevance and possible applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25963274','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25963274"><span>An evaluation of nasal bone and aperture shape among three South African populations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McDowell, Jennifer L; Kenyhercz, Michael W; L'Abbé, Ericka N</p> <p>2015-07-01</p> <p>Reliable and valid population specific standards are necessary to accurately develop a biological profile, which includes an estimation of peer-reported social identification (Hefner, 2009). During the last 300 years, colonialism, slavery and apartheid created geographic, physical and social divisions of population groups in South Africa. The purpose of this study was to evaluate variation in nasal bone and aperture shape in a modern population of black, white, and coloured South Africans using standard craniometric variables and geometric morphometrics, namely general <span class="hlt">Procrustes</span> and elliptical Fourier analyses. Fourteen standard landmarks were digitally recorded or computationally derived from 310 crania using a 3D coordinate digitizer for discriminant function, principal components and generalized <span class="hlt">Procrustes</span> analyses. For elliptical Fourier <span class="hlt">analysis</span>, outlines of the nasal aperture were generated from standardized photographs. All classification accuracies were better than chance; the lowest accuracies were for coloured and the highest accuracies were for white South Africans. Most difficulties arose in distinguishing coloured and black South African groups from each other. Generally, misclassifications were noted between the sexes within each group rather than among groups, which suggests that sex has less influence on nasal bone and aperture shape than ancestry. Quantifiable variation in shape of the nasal aperture region between white and non-white South African groups was observed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988MolPh..63...65F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988MolPh..63...65F"><span>Dielectric relaxation of 1,2,6-hexanetriol at frequencies from 1 mHz to 10 MHz and at pressures to 1 <span class="hlt">GPa</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Forsman, Hans</p> <p></p> <p>The complex permittivity of supercooled 1,2,6-hexanetriol has been studied at frequencies from 1 mHz to 10 MHz at pressures up to 1 <span class="hlt">GPa</span> and at the temperatures 238 K, 248 K and 258 K. The dielectric loss peak is significantly broadened with increasing pressure. A numerical fitting routine has been developed to analyse the results in terms of the Dissado and Hill (DH) cooperative cluster model for relaxation. The peak broadening is explicitly expressed by the shape parameters of the DH theory which are associated with a change in correlation between neighbouring molecules. The relaxation results are also analysed using the Davidson and Cole function. The results of 1,2,6-hexanetriol at high pressure are compared with corresponding data for glycerol. It is found that 1,2,6-hexanetriol exhibits a higher degree of cooperative relaxation according to the DH theory, has a lower static dielectric susceptibility and has a longer characteristic relaxation time than glycerol.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1036318-laboratory-shock-experiments-basalt-iron-sulfate-mixes-gpa-relevance-martian-reolith-component-present-shergotties','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1036318-laboratory-shock-experiments-basalt-iron-sulfate-mixes-gpa-relevance-martian-reolith-component-present-shergotties"><span>Laboratory Shock Experiments on Basalt - Iron Sulfate Mixes at ~ 40 - 50 <span class="hlt">GPa</span> and their Relevance to the Martian Reolith Component Present in Shergotties</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Rao, M N; Nyquist, L E; Ross, D K</p> <p>2012-03-14</p> <p>Basaltic shergottites such as Shergotty, Zagami and EET79001 contain impact melt glass pockets that are rich in Martian atmospheric gases and are known as gas-rich impact-melt (GRIM) glasses. These glasses show evidence for the presence of a Martian regolith component based on Sm and Kr isotopic studies. The GRIM glasses are sometimes embedded with clusters of innumerable micron-sized iron-sulfide blebs associated with minor amounts of iron sulfate particles. These sulfide blebs are secondary in origin and are not related to the primary igneous sulfides occurring in Martian meteorites. The material comprising these glasses arises from the highly oxidizing Martian surfacemore » and sulfur is unlikely to occur as sulfide in the Martian regoilith. Instead, sulfur is shown to occur as sulfate based on APXS and Mossbauer results obtained by the Opportunity and Spirit rovers at Meridiani and Gusev. We have earlier suggested that the micron-sized iron sulfide globules in GRIM glasses were likely produced by shock-reduction of iron sulfate occurring in the regolith at the time when the GRIM glasses were produced by the meteoroid impact that launched the Martian meteorites into space. As a result of high energy deposition by shock (~ 40-60 <span class="hlt">GPa</span>), the iron sulfate bearing phases are likely to melt along with other regolith components and will get reduced to immiscible sulfide fluid under reducing conditions. On quenching, this generates a dispersion of micron-scale sulfide blebs. The reducing agents in our case are likely to be H 2 and CO which were shock-implanted from the Martian atmosphere into these glasses along with the noble gases. We conducted lab simulation experiments in the Lindhurst Laboratory of Experimental Geophysics at Caltech and the Experimental Impact Laboratory at JSC to test whether iron sulfide globules can be produced by impact-driven reduction of iron sulfate by subjecting Columbia River Basalt (CRB) and ferric sulfate mixtures to shock pressures</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3707565','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3707565"><span>Structural Determinants at the Interface of the ARC2 and Leucine-Rich Repeat Domains Control the Activation of the Plant Immune Receptors Rx1 and <span class="hlt">Gpa</span>21[C][W][OA</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Slootweg, Erik J.; Spiridon, Laurentiu N.; Roosien, Jan; Butterbach, Patrick; Pomp, Rikus; Westerhof, Lotte; Wilbers, Ruud; Bakker, Erin; Bakker, Jaap; Petrescu, Andrei-José; Smant, Geert; Goverse, Aska</p> <p>2013-01-01</p> <p>Many plant and animal immune receptors have a modular nucleotide-binding-leucine-rich repeat (NB-LRR) architecture in which a nucleotide-binding switch domain, NB-ARC, is tethered to a LRR sensor domain. The cooperation between the switch and sensor domains, which regulates the activation of these proteins, is poorly understood. Here, we report structural determinants governing the interaction between the NB-ARC and LRR in the highly homologous plant immune receptors <span class="hlt">Gpa</span>2 and Rx1, which recognize the potato cyst nematode Globodera pallida and Potato virus X, respectively. Systematic shuffling of polymorphic sites between <span class="hlt">Gpa</span>2 and Rx1 showed that a minimal region in the ARC2 and N-terminal repeats of the LRR domain coordinate the activation state of the protein. We identified two closely spaced amino acid residues in this region of the ARC2 (positions 401 and 403) that distinguish between autoactivation and effector-triggered activation. Furthermore, a highly acidic loop region in the ARC2 domain and basic patches in the N-terminal end of the LRR domain were demonstrated to be required for the physical interaction between the ARC2 and LRR. The NB-ARC and LRR domains dissociate upon effector-dependent activation, and the complementary-charged regions are predicted to mediate a fast reassociation, enabling multiple rounds of activation. Finally, we present a mechanistic model showing how the ARC2, NB, and N-terminal half of the LRR form a clamp, which regulates the dissociation and reassociation of the switch and sensor domains in NB-LRR proteins. PMID:23660837</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008E%26PSL.274..327M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008E%26PSL.274..327M"><span>Ab initio elastic properties of talc from 0 to 12 <span class="hlt">GPa</span>: Interpretation of seismic velocities at mantle pressures and prediction of auxetic behaviour at low pressure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mainprice, David; Le Page, Yvon; Rodgers, John; Jouanna, Paul</p> <p>2008-10-01</p> <p>Talc is a hydrous magnesium rich layered silicate that is widely disseminated in the Earth from the seafloor to over 100 km depth, in ultra-high pressure metamorphism of oceanic crust. In this paper we determine the single crystal elastic constants at pressures from 0 to 12 <span class="hlt">GPa</span> of talc triclinic ( C 1¯) and monoclinic (C2/ c) polytypes using ab initio methods. We find that talc has an extraordinarily high elastic anisotropy at zero pressure that reduces with increasing pressure. The exceptional anisotropy is complemented by a negative Poisson's ratio for many directions in crystal space. Calculations show that talc is not only one of very few common minerals to exhibit auxetic behaviour, but the magnitude of this effect may be the largest reported so far for a mineral. The compression (Vp) and shear (Vs) wave velocity anisotropy is 80% and 85% for the triclinic polytype. At pressures where talc is known be stable in the Earth (up to 5 <span class="hlt">GPa</span>) the Vp and Vs anisotropy is reduced to about 40% for both velocities, which is still a very high value. Vp is slow parallel to the c-axis and fast perpendicular to it. This remains unchanged with increasing pressure and is observed in both polytypes. The shear wave splitting (difference between fast and slow S-wave velocities) at low pressure has high values in the plane normal to the c-axis, with a maximum near the a*-axis in the triclinic and the b-axis in the monoclinic polytype. The c-axis is the direction of minimum splitting. The pattern of shear wave splitting does not change significantly with pressure. The volume fraction of talc varies between 11 and 41% for hydrated mantle rocks, but the lack of data on the crystallographic preferred orientation (CPO) precludes a detailed <span class="hlt">analysis</span> of the impact of talc on seismic anisotropy in subduction zones. However, it is highly likely that CPO can easily develop in zones of deformation due to the platy habit of talc crystals. For random aggregates of talc, the isotropic Vp, Vs</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1467726','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1467726"><span>Localisation of deformations of the midfacial complex in subjects with class III malocclusions employing thin-plate spline <span class="hlt">analysis</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>SINGH, G. D.; McNAMARA JR, J. A.; LOZANOFF, S.</p> <p>1997-01-01</p> <p>This study determines deformations of the midface that contribute to a class III appearance, employing thin-plate spline <span class="hlt">analysis</span>. A total of 135 lateral cephalographs of prepubertal children of European-American descent with either class III malocclusions or a class I molar occlusion were compared. The cephalographs were traced and checked, and 7 homologous landmarks of the midface were identified and digitised. The data sets were scaled to an equivalent size and subjected to <span class="hlt">Procrustes</span> <span class="hlt">analysis</span>. These statistical tests indicated significant differences (P<0.05) between the averaged class I and class III morphologies. Thin-plate spline <span class="hlt">analysis</span> indicated that both affine and nonaffine transformations contribute towards the total spline for the averaged midfacial configuration. For nonaffine transformations, partial warp 3 had the highest magnitude, indicating the large scale deformations of the midfacial configuration. These deformations affected the palatal landmarks, and were associated with compression of the midfacial complex in the anteroposterior plane predominantly. Partial warp 4 produced some vertical compression of the posterior aspect of the midfacial complex whereas partial warps 1 and 2 indicated localised shape changes of the maxillary alveolus region. Large spatial-scale deformations therefore affect the midfacial complex in an anteroposterior axis, in combination with vertical compression and localised distortions. These deformations may represent a developmental diminution of the palatal complex anteroposteriorly that, allied with vertical shortening of midfacial height posteriorly, results in class III malocclusions with a retrusive midfacial profile. PMID:9449078</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9449078','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9449078"><span>Localisation of deformations of the midfacial complex in subjects with class III malocclusions employing thin-plate spline <span class="hlt">analysis</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Singh, G D; McNamara, J A; Lozanoff, S</p> <p>1997-11-01</p> <p>This study determines deformations of the midface that contribute to a class III appearance, employing thinplate spline <span class="hlt">analysis</span>. A total of 135 lateral cephalographs of prepubertal children of European-American descent with either class III malocclusions or a class I molar occlusion were compared. The cephalographs were traced and checked, and 7 homologous landmarks of the midface were identified and digitised. The data sets were scaled to an equivalent size and subjected to <span class="hlt">Procrustes</span> <span class="hlt">analysis</span>. These statistical tests indicated significant differences (P < 0.05) between the averaged class I and class III morphologies. Thinplate spline <span class="hlt">analysis</span> indicated that both affine and nonaffine transformations contribute towards the total spline for the averaged midfacial configuration. For nonaffine transformations, partial warp 3 had the highest magnitude, indicating the large scale deformations of the midfacial configuration. These deformations affected the palatal landmarks, and were associated with compression of the midfacial complex in the anteroposterior plane predominantly. Partial warp 4 produced some vertical compression of the posterior aspect of the midfacial complex whereas partial warps 1 and 2 indicated localised shape changes of the maxillary alveolus region. large spatial-scale deformations therefore affect the midfacial complex in an anteroposterior axis, in combination with vertical compression and localised distortions. These deformations may represent a developmental diminution of the palatal complex anteroposteriorly that, allied with vertical shortening of midfacial height posteriorly, results in class III malocclusions with a retrusive midfacial profile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMDI41B4331Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMDI41B4331Y"><span>In Situ Measurements of the Post-Spinel and Post-Garnet Phase Boundaries in Pyrolite at 17-32 <span class="hlt">GPa</span> and 1500-2400 K</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ye, Y.; Gu, C.; Shim, S. H.; Prakapenka, V.; Meng, Y.</p> <p>2014-12-01</p> <p>Recent seismic studies have revealed complex structures near 660-km depth. In order to understand the effects of composition and temperature, we measured the depth and Clapeyron slope of the post-spinel and post-garnet boundaries at the pressure-temperature conditions of 600-700 km depths in pyrolitic compositions: (1) MgO-Al2O3-SiO2 (MAS) and (2) CaO-MgO-Al2O3-SiO2-FeO (CMASF). Glass starting materials were mixed with either gold or platinum powder (10 wt%) for laser coupling and internal pressure scale. Cold compressed foils of the mixtures were loaded in the diamond-anvil cell together with Ar or KCl for thermal insulation and pressure transmission. X-ray diffraction patterns were measured for the samples in the diamond-anvil cell at in situ high pressure and high temperature combined with double side laser heating at beamlines 13-IDD (GSECARS) and 16-IDB (HPCAT) in the Advanced Photon Source. Within 5 to 8 minutes of heating, stable crystalline phase assemblages were formed and persisted with further heating for 20 to 30 minutes. A total of 160 heating cycles were conducted at different pressures and temperatures, providing tight constrains on the phase boundaries. Our data show that the post-spinel transition occurs at 23.6-24.5 <span class="hlt">GPa</span> and 1850 K with a Clapeyron slope of -2.5(4) MPa/K if the Pt pressure scales are used, consistent with the seismic observation of the 660 discontinuity. The post-garnet boundary occurs at 24.2-27.5 <span class="hlt">GPa</span> and 1900 - 2450 K. We found that the Clapeyron slope of the post-garnet transition increases with Fe: from 2.4 MPa/K for MAS to 6.2 MPa/K for CMASF. Below 1900 K, garnet disappears near the post-spinel boundary within the resolution of our measurements. Our new data supports the notion that the 660 discontinuity is dominated by the post-spinel phase transition below 1900 K while dominated by the post-garnet phase transition above 1900 K. However, our data indicate much larger Clapeyron slope of the post-garnet transition, suggesting</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V51B0994D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V51B0994D"><span>Crystallization of Skeletal Diamonds from Graphite and Natural Coal in Presence of Hydrous Fluids at P=8 <span class="hlt">GPa</span> and T=1400-1500° C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dobrzhinetskaya, L. F.; Renfro, A. P.; Green, H. W.</p> <p>2001-12-01</p> <p>Most metamorphic microdiamonds from crustal UHP rocks of the Kokchetav massive, Kazakhstan are characterized by skeletal-hopper crystals, cuboid-like crystals with cavities "healed over" by graphite, rose-like crystals, and other imperfect morphologies. According to the classical theory of crystal growth at thermodynamic equilibrium, only shapes with a minimum surface energy are stable. Thus imperfect crystallographic forms of most metamorphic diamonds formally may be interpreted as metastable while the presence of other high pressure phases associated with diamond indicates that the rocks have been subjected to UHP metamorphism within the diamond stability field. The classical theory also says that a skeletal-hopper crystal is one that develops under conditions of rapid growth, a high degree of supersaturation and in the presence of impurities. In contrast to these observations, most experiments on diamond synthesis at high P (5-7.7 <span class="hlt">GPa</span>) and T (1250 - 1900° C) from graphite (Wang et al., 1999; Hong et al., 1999; Yamaoka et al., 2000) and carbonate material (Pal'anov et al., 1999; Sokol et al.,2000) in presence of fluid phase produced perfect octahedral and cube-octahedral diamond crystals. Advanced analytical research on metamorphic diamonds and their inclusions has demonstrated that they were crystallized from a multicomponent COH-rich supercritical fluid phase, the composition of which suggests intermixture of crustal and mantle components (de Corte et al., 1999; Dobrzhinetskaya et al., 2001, Stockhert et al., 2001). We have recently synthesized imperfect diamond crystals (skeletal-hopper morphologies with effect of etching of the diamond surfaces) from graphite and natural coal + 2% Mg(OH)2 as a source for fluid phase. Conditions of experiments are: P=8-8.5 <span class="hlt">GPa</span>, T=1400-1500° C, t=14 to 136 hours. Our experimental data are in a good agreement with similar experiments conducted by Kanda et al. (1984) who showed that with increasing water content of the system</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120001831','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120001831"><span>Laboratory Shock Experiments on Basalt - Iron Sulfate Mixes at Approximately 40-50 <span class="hlt">GPa</span> and Their Relevance to the Martian Regolith Component Present in Shergottites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rao, M. N.; Nyquist, L. E.; Ross, D. K.; Asimow, P. D.; See, T.; Sutton, S.; Cardernas, F.; Montes, R.; Cintala, M.</p> <p>2012-01-01</p> <p>Basaltic shergottites such as Shergotty, Zagami and EET79001 contain impact melt glass pockets that are rich in Martian atmospheric gases [1] and are known as gas-rich impact-melt (GRIM) glasses. These glasses show evidence for the presence of a Martian regolith component based on Sm and Kr isotopic studies [2]. The GRIM glasses are sometimes embedded with clusters of innumerable micron-sized iron-sulfide blebs associated with minor amounts of iron sulfate particles [3, 4]. These sulfide blebs are secondary in origin and are not related to the primary igneous sulfides occurring in Martian meteorites. The material comprising these glasses arises from the highly oxidizing Martian surface and sulfur is unlikely to occur as sulfide in the Martian regoilith. Instead, sulfur is shown to occur as sulfate based on APXS and Mossbauer results obtained by the Opportunity and Spirit rovers at Meridiani and Gusev [5]. We have earlier suggested that the micron-sized iron sulfide globules in GRIM glasses were likely produced by shock-reduction of iron sulfate occurring in the regolith at the time when the GRIM glasses were produced by the meteoroid impact that launched the Martian meteorites into space [6]. As a result of high energy deposition by shock (approx. 40-60 <span class="hlt">GPa</span>), the iron sulfate bearing phases are likely to melt along with other regolith components and will get reduced to immiscible sulfide fluid under reducing conditions. On quenching, this generates a dispersion of micron-scale sulfide blebs. The reducing agents in our case are likely to be H2 and CO which were shock-implanted from the Martian atmosphere into these glasses along with the noble gases. We conducted lab simulation experiments in the Lindhurst Laboratory of Experimental Geophysics at Caltech and the Experimental Impact Laboratory at JSC to test whether iron sulfide globules can be produced by impact-driven reduction of iron sulfate by subjecting Columbia River Basalt (CRB) and ferric sulfate mixtures to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4395437','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4395437"><span>A New 4D Trajectory-Based Approach Unveils Abnormal LV Revolution Dynamics in Hypertrophic Cardiomyopathy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Madeo, Andrea; Piras, Paolo; Re, Federica; Gabriele, Stefano; Nardinocchi, Paola; Teresi, Luciano; Torromeo, Concetta; Chialastri, Claudia; Schiariti, Michele; Giura, Geltrude; Evangelista, Antonietta; Dominici, Tania; Varano, Valerio; Zachara, Elisabetta; Puddu, Paolo Emilio</p> <p>2015-01-01</p> <p>The assessment of left ventricular shape changes during cardiac revolution may be a new step in clinical cardiology to ease early diagnosis and treatment. To quantify these changes, only point registration was adopted and neither Generalized <span class="hlt">Procrustes</span> <span class="hlt">Analysis</span> nor Principal Component <span class="hlt">Analysis</span> were applied as we did previously to study a group of healthy subjects. Here, we extend to patients affected by hypertrophic cardiomyopathy the original approach and preliminarily include genotype positive/phenotype negative individuals to explore the potential that incumbent pathology might also be detected. Using 3D Speckle Tracking Echocardiography, we recorded left ventricular shape of 48 healthy subjects, 24 patients affected by hypertrophic cardiomyopathy and 3 genotype positive/phenotype negative individuals. We then applied Generalized <span class="hlt">Procrustes</span> <span class="hlt">Analysis</span> and Principal Component <span class="hlt">Analysis</span> and inter-individual differences were cleaned by Parallel Transport performed on the tangent space, along the horizontal geodesic, between the per-subject consensuses and the grand mean. Endocardial and epicardial layers were evaluated separately, different from many ecocardiographic applications. Under a common Principal Component <span class="hlt">Analysis</span>, we then evaluated left ventricle morphological changes (at both layers) explained by first Principal Component scores. Trajectories’ shape and orientation were investigated and contrasted. Logistic regression and Receiver Operating Characteristic curves were used to compare these morphometric indicators with traditional 3D Speckle Tracking Echocardiography global parameters. Geometric morphometrics indicators performed better than 3D Speckle Tracking Echocardiography global parameters in recognizing pathology both in systole and diastole. Genotype positive/phenotype negative individuals clustered with patients affected by hypertrophic cardiomyopathy during diastole, suggesting that incumbent pathology may indeed be foreseen by these methods</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012E%26PSL.313...79S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012E%26PSL.313...79S"><span>Sound velocity measurements in dhcp-FeH up to 70 <span class="hlt">GPa</span> with inelastic X-ray scattering: Implications for the composition of the Earth's core</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shibazaki, Yuki; Ohtani, Eiji; Fukui, Hiroshi; Sakai, Takeshi; Kamada, Seiji; Ishikawa, Daisuke; Tsutsui, Satoshi; Baron, Alfred Q. R.; Nishitani, Naoya; Hirao, Naohisa; Takemura, Kenichi</p> <p>2012-01-01</p> <p>We have determined the density evolution of the sound velocity of dhcp-FeH x ( x ≈ 1) up to 70 <span class="hlt">GPa</span> at room temperature, by inelastic X-ray scattering and by X-ray diffraction. We find that the variation of VP with density is different for the ferromagnetic and nonmagnetic dhcp-FeH x, and that only nonmagnetic dhcp-FeH x follows Birch's law. Combining our results with Birch's law for iron and assuming an ideal two-component mixing model, we obtain an upper bound of the hydrogen content in the Earth's inner core, 0.23(6) wt.% H, corresponding to FeH 0.13(3). The iron alloy with 0.23(6) wt.% H can satisfy the density, and compressional and shear sound velocities of the PREM inner core, assuming that there are no other light elements in the inner core.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMMR14A..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMMR14A..07L"><span>Hydrogen Incorporation into Olivine at 9-15 <span class="hlt">GPa</span>: Implication for Water Dynamics near the 410-km Seismic Discontinuity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Litasov, K.; Ohtani, E.; Kagi, H.; Shatskiy, A.; Ghosh, S.; Lakshtanov, D.; Bass, J.; Matveev, S.</p> <p>2006-12-01</p> <p>The hydrogen solubility and hydrogen incorporation mechanism into (Mg,Fe)2SiO4 olivine have been studied at pressures of 9-15 <span class="hlt">GPa</span> and temperatures of 1100-2000°C. Samples were synthesized using a multianvil apparatus from Fo90 + 4-15 wt.% H2O mixture without controlling oxygen fugacity. Also, pure forsterite crystals were synthesized in KHCO3-Mg(OH)2 flux. Samples were studied by Fourier Transform Infrared spectroscopy (FTIR) and H (H2O) contents were calculated from IR spectra using the calibration by Bell et al. (2003). The hydrogen solubility increases with pressure, but the temperature dependence is complex. The hydrogen solubility increases from 1100-1400°C and then decreases at 1400-2000°C. Maximum hydrogen solubility, equivalent to 1.15 wt.% H2O, was determined in olivine at 13.5 <span class="hlt">GPa</span> and 1400°C. At temperatures of 1800-2000°C the H2O contents of olivine are very low (280-590 ppm). Hydrogen solubility in Fo90 is consistent with that in pure forsterite studied by Lemaire et al. (2004) and Smyth et al. (2006) indicating minor influence of Fe on hydrogen incorporation. The IR spectra of olivines are composed of several OH absorption bands at 3300-3613 cm-1. IR spectra with the E-field vector parallel to the a-axis show the strongest absorbance, dominated by peaks at 3613 and 3579 cm-1. Although structural calculations are consistent with hydrogen incorporation into octahedral vacancies in olivine (e.g. Smyth et al., 2006; Kudoh et al., 2006) we strongly suggest that majority of observed peaks (at 3533, 3548, 3566, 3579, and 3613 cm-1) are due to hydrogen associated with Si- vacancies. This is consistent with microprobe analyses of the samples, which show a clear deficit of Si in olivines at the highest H2O-contents. Minor bands at 3300-3400 cm-1 may be due to Fe3+ substitution and those at 3400-3500 cm-1 due to vacancies in Mg structural positions. The peak at 3598 cm-1 previously attributed to Mg-vacancies should be addressed to Si-vacancies. The strongest</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JSSCh.238...74K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JSSCh.238...74K"><span>High pressure structure studies of 6H-SrIrO3 and the octahedral tilting in 3C-SrIrO3 towards a post-perovskite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kronbo, Camilla H.; Nielsen, Morten B.; Kevy, Simone M.; Parisiades, Paraskevas; Bremholm, Martin</p> <p>2016-06-01</p> <p>The high pressure behaviors of the two perovskite structures (hexagonal 6H-SrIrO3 and orthorhombic 3C-SrIrO3) have been studied in diamond anvil cells to 43 and 60 <span class="hlt">GPa</span>, respectively, using synchrotron powder X-ray diffraction. 6H-SrIrO3 was first synthesized at ambient pressure and subsequently transformed into 3C-SrIrO3 in a large volume press at 8.8 <span class="hlt">GPa</span> and 1000 °C. Both polymorphs were found to retain the initial symmetry up to the highest pressures measured, but in the case of 6H-SrIrO3, two anomalies were identified: a change in the axial compressibilities at 24 <span class="hlt">GPa</span> and a change in both the axial and volume compressibilities at 32 <span class="hlt">GPa</span>. Fitting a 3rd order Birch-Murnaghan equation of state to the obtained P-V data yielded bulk moduli of K0=151.5(12) <span class="hlt">GPa</span> (fitted range 0<P<30 <span class="hlt">GPa</span>) for 6H-SrIrO3 and K0=187.1(9) <span class="hlt">GPa</span> for 3C-SrIrO3. <span class="hlt">Analysis</span> of the structural parameters for 6H-SrIrO3 aided by F-f plots suggests the anomalies are caused by changes in the compression mechanism. Comparison of the two polymorphs reveals that 6H-SrIrO3 becomes less compressible than 3C-SrIrO3 above 32 <span class="hlt">GPa</span> as a result of the mechanistic change, and a crossing of their P-V curves is avoided. For 3C-SrIrO3, <span class="hlt">analysis</span> of the octahedral tilt angles shows that these increase monotonically from the ambient value of 7.23(6) to 23.0(2)° at 60 <span class="hlt">GPa</span> suggesting that a transition to a post-perovskite is approached.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPS...277..169S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPS...277..169S"><span>Component-/structure-dependent elasticity of solid electrolyte interphase layer in Li-ion batteries: Experimental and computational studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shin, Hosop; Park, Jonghyun; Han, Sangwoo; Sastry, Ann Marie; Lu, Wei</p> <p>2015-03-01</p> <p>The mechanical instability of the Solid Electrolyte Interphase (SEI) layer in lithium ion (Li-ion) batteries causes significant side reactions resulting in Li-ion consumption and cell impedance rise by forming further SEI layers, which eventually leads to battery capacity fade and power fade. In this paper, the composition-/structure-dependent elasticity of the SEI layer is investigated via Atomic Force Microscopy (AFM) measurements coupled with X-ray Photoelectron Spectroscopy (XPS) <span class="hlt">analysis</span>, and atomistic calculations. It is observed that the inner layer is stiffer than the outer layer. The measured Young's moduli are mostly in the range of 0.2-4.5 <span class="hlt">GPa</span>, while some values above 80 <span class="hlt">GPa</span> are also observed. This wide variation of the observed elastic modulus is elucidated by atomistic calculations with a focus on chemical and structural <span class="hlt">analysis</span>. The numerical <span class="hlt">analysis</span> shows the Young's moduli range from 2.4 <span class="hlt">GPa</span> to 58.1 <span class="hlt">GPa</span> in the order of the polymeric, organic, and amorphous inorganic components. The crystalline inorganic component (LiF) shows the highest value (135.3 <span class="hlt">GPa</span>) among the SEI species. This quantitative observation on the elasticity of individual components of the SEI layer must be essential to analyzing the mechanical behavior of the SEI layer and to optimizing and controlling it.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17050585','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17050585"><span>Some dissociating factors in the <span class="hlt">analysis</span> of structural and functional progressive damage in open-angle glaucoma.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hudson, C J W; Kim, L S; Hancock, S A; Cunliffe, I A; Wild, J M</p> <p>2007-05-01</p> <p>To identify the presence, and origin, of any "dissociating factors" inherent to the techniques for evaluating progression that mask the relationship between structural and functional progression in open-angle glaucoma (OAG). 23 patients (14 with OAG and 9 with ocular hypertension (OHT)) who had received serial Heidelberg Retina Tomograph (HRT II) and Humphrey Field Analyser (HFA) examinations for >or=5 years (mean 78.4 months (SD 9.5), range 60-101 months) were identified. Evidence of progressive disease was retrospectively evaluated in one eye of each patient using the Topographic Change <span class="hlt">Analysis</span> (TCA) and Glaucoma Progression <span class="hlt">Analysis</span> (<span class="hlt">GPA</span>) for the HRT II and HFA, respectively. Six patients were stable by both techniques; four exhibited both structural and functional progression; seven exhibited structural progression, only, and six showed functional progression, only. Three types of dissociating factors were identified. TCA failed to identify progressive structural damage in the presence of advanced optic nerve head damage. <span class="hlt">GPA</span> failed to identify progressive functional damage at stimulus locations, with sensitivities exhibiting test-retest variability beyond the maximum stimulus luminance of the perimeter, and where a perimetric learning effect was apparent. The three dissociating factors accounted for nine of the 13 patients who exhibited a lack of concordance between structural and functional progressive damage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25338937','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25338937"><span>Three-dimensional geometric morphometric <span class="hlt">analysis</span> of talar morphology in extant gorilla taxa from highland and lowland habitats.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Knigge, Ryan P; Tocheri, Matthew W; Orr, Caley M; Mcnulty, Kieran P</p> <p>2015-01-01</p> <p>Western gorillas (Gorilla gorilla) are known to climb significantly more often than eastern gorillas (Gorilla beringei), a behavioral distinction attributable to major differences in their respective habitats (i.e., highland vs. lowland). Genetic evidence suggests that the lineages leading to these taxa began diverging from one another between approximately 1 and 3 million years ago. Thus, gorillas offer a special opportunity to examine the degree to which morphology of recently diverged taxa may be "fine-tuned" to differing ecological requirements. Using three-dimensional (3D) geometric morphometrics, we compared talar morphology in a sample of 87 specimens including western (lowland), mountain (highland), and grauer gorillas (lowland and highland populations). Talar shape was captured with a series of landmarks and semilandmarks superimposed by generalized <span class="hlt">Procrustes</span> <span class="hlt">analysis</span>. A between-group principal components <span class="hlt">analysis</span> of overall talar shape separates gorillas by ecological habitat and by taxon. An <span class="hlt">analysis</span> of only the trochlea and lateral malleolar facet identifies subtle variations in trochlear shape between western lowland and lowland grauer gorillas, potentially indicative of convergent evolution of arboreal adaptations in the talus. Lastly, talar shape scales differently with centroid size for highland and lowland gorillas, suggesting that ankle morphology may track body-size mediated variation in arboreal behaviors differently depending on ecological setting. Several of the observed shape differences are linked biomechanically to the facilitation of climbing in lowland gorillas and to stability and load-bearing on terrestrial substrates in the highland taxa, providing an important comparative model for studying morphological variation in groups known only from fossils (e.g., early hominins). © 2014 Wiley Periodicals, Inc.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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