Ab initio vel ex eventu

Science.gov (United States)

Thiessen, P. A.; Treder, H.-J.

Der gegenwärtige Stand der physikalischen Erkenntnis, in Sonderheit die Atomistik und die Quantentheorie, ermöglicht (in wohldefinierten Energie-Bereichen) eine ab initio-Berechnung aller physikalischen und chemischen Prozesse und Strukturen. Die Schrödinger-Gleichung erlaubt zusammen mit den Prinzipien der Quantenstatistik (Pauli-Prinzip) aus dem Planckschen Wirkungsquantum h und den atomischen Konstanten die Berechnung aller Energieumsätze, Zeitabläufe etc., die insbesondere die chemische Physik bestimmen. Die Rechenresultate gelten auch quantitativ bis auf die unvermeidliche Stochastik.Die ab initio-Berechnungen korrespondieren einerseits und sind andererseits komplementär zu den auf den Methoden der theoretischen Chemie und der klassischen Thermodynamik beruhenden Ergebnissen ex eventu. Die theoretische Behandlung ab initio führt zu mathematischen Experimenten, die die Laboratoriums-Experimente ergänzen oder auch substituieren.Translated AbstractAb initio vel ex eventuThe present state of physical knowledge, in peculiar atomistic and quantum theory, makes an ab initio calculation of all physical and chemical processes and structures possible (in well defined reaches of energy). The Schrödinger equation together with the principles of quantum statistics (Pauli principle) permits from the Planck and atomistic constants to calculate all exchanges of energy, courses of time, etc. which govern chemical physics. The calculated results are valid even quantitatively apart from the unavoidable stochastics.These ab initio calculations on the one hand correspond and are on the other complimentary to results ex eventu based on the methods of theoretical chemistry and classical thermodynamics. Theoretical treatment ab initio leads to mathematical experiments which add to or even substitute experiments in the laboratory.

ITC Guidelines on Quality Control in Scoring, Test Analysis, and Reporting of Test Scores

Science.gov (United States)

Allalouf, Avi

2014-01-01

The Quality Control (QC) Guidelines are intended to increase the efficiency, precision, and accuracy of the scoring, analysis, and reporting process of testing. The QC Guidelines focus on large-scale testing operations where multiple forms of tests are created for use on set dates. However, they may also be used for a wide variety of other testing…

Automatic ECG quality scoring methodology: mimicking human annotators

International Nuclear Information System (INIS)

Johannesen, Lars; Galeotti, Loriano

2012-01-01

An algorithm to determine the quality of electrocardiograms (ECGs) can enable inexperienced nurses and paramedics to record ECGs of sufficient diagnostic quality. Previously, we proposed an algorithm for determining if ECG recordings are of acceptable quality, which was entered in the PhysioNet Challenge 2011. In the present work, we propose an improved two-step algorithm, which first rejects ECGs with macroscopic errors (signal absent, large voltage shifts or saturation) and subsequently quantifies the noise (baseline, powerline or muscular noise) on a continuous scale. The performance of the improved algorithm was evaluated using the PhysioNet Challenge database (1500 ECGs rated by humans for signal quality). We achieved a classification accuracy of 92.3% on the training set and 90.0% on the test set. The improved algorithm is capable of detecting ECGs with macroscopic errors and giving the user a score of the overall quality. This allows the user to assess the degree of noise and decide if it is acceptable depending on the purpose of the recording. (paper)

Rating the methodological quality in systematic reviews of studies on measurement properties: a scoring system for the COSMIN checklist.

Science.gov (United States)

Terwee, Caroline B; Mokkink, Lidwine B; Knol, Dirk L; Ostelo, Raymond W J G; Bouter, Lex M; de Vet, Henrica C W

2012-05-01

The COSMIN checklist is a standardized tool for assessing the methodological quality of studies on measurement properties. It contains 9 boxes, each dealing with one measurement property, with 5-18 items per box about design aspects and statistical methods. Our aim was to develop a scoring system for the COSMIN checklist to calculate quality scores per measurement property when using the checklist in systematic reviews of measurement properties. The scoring system was developed based on discussions among experts and testing of the scoring system on 46 articles from a systematic review. Four response options were defined for each COSMIN item (excellent, good, fair, and poor). A quality score per measurement property is obtained by taking the lowest rating of any item in a box ("worst score counts"). Specific criteria for excellent, good, fair, and poor quality for each COSMIN item are described. In defining the criteria, the "worst score counts" algorithm was taken into consideration. This means that only fatal flaws were defined as poor quality. The scores of the 46 articles show how the scoring system can be used to provide an overview of the methodological quality of studies included in a systematic review of measurement properties. Based on experience in testing this scoring system on 46 articles, the COSMIN checklist with the proposed scoring system seems to be a useful tool for assessing the methodological quality of studies included in systematic reviews of measurement properties.

A Novel Scoring Metrics for Quality Assurance of Ocean Color Observations

Science.gov (United States)

Wei, J.; Lee, Z.

2016-02-01

Interpretation of the ocean bio-optical properties from ocean color observations depends on the quality of the ocean color data, specifically the spectrum of remote sensing reflectance (Rrs). The in situ and remotely measured Rrs spectra are inevitably subject to errors induced by instrument calibration, sea-surface correction and atmospheric correction, and other environmental factors. Great efforts have been devoted to the ocean color calibration and validation. Yet, there exist no objective and consensus criteria for assessment of the ocean color data quality. In this study, the gap is filled by developing a novel metrics for such data quality assurance and quality control (QA/QC). This new QA metrics is not intended to discard "suspicious" Rrs spectra from available datasets. Rather, it takes into account the Rrs spectral shapes and amplitudes as a whole and grades each Rrs spectrum. This scoring system is developed based on a large ensemble of in situ hyperspectral remote sensing reflectance data measured from various aquatic environments and processed with robust procedures. This system is further tested with the NASA bio-Optical Marine Algorithm Data set (NOMAD), with results indicating significant improvements in the estimation of bio-optical properties when Rrs spectra marked with higher quality assurance are used. This scoring system is further verified with simulated data and satellite ocean color data in various regions, and we envision higher quality ocean color products with the implementation of such a quality screening system.

Collective rotation from ab initio theory

International Nuclear Information System (INIS)

Caprio, M.A.; Maris, P.; Vary, J.P.; Smith, R.

2015-01-01

Through ab initio approaches in nuclear theory, we may now seek to quantitatively understand the wealth of nuclear collective phenomena starting from the underlying internucleon interactions. No-core configuration interaction (NCCI) calculations for p-shell nuclei give rise to rotational bands, as evidenced by rotational patterns for excitation energies, electromagnetic moments and electromagnetic transitions. In this review, NCCI calculations of 7–9 Be are used to illustrate and explore ab initio rotational structure, and the resulting predictions for rotational band properties are compared with experiment. We highlight the robustness of ab initio rotational predictions across different choices for the internucleon interaction. (author)

Using quality scores and longer reads improves accuracy of Solexa read mapping

Directory of Open Access Journals (Sweden)

Xuan Zhenyu

2008-02-01

Full Text Available Abstract Background Second-generation sequencing has the potential to revolutionize genomics and impact all areas of biomedical science. New technologies will make re-sequencing widely available for such applications as identifying genome variations or interrogating the oligonucleotide content of a large sample (e.g. ChIP-sequencing. The increase in speed, sensitivity and availability of sequencing technology brings demand for advances in computational technology to perform associated analysis tasks. The Solexa/Illumina 1G sequencer can produce tens of millions of reads, ranging in length from ~25–50 nt, in a single experiment. Accurately mapping the reads back to a reference genome is a critical task in almost all applications. Two sources of information that are often ignored when mapping reads from the Solexa technology are the 3' ends of longer reads, which contain a much higher frequency of sequencing errors, and the base-call quality scores. Results To investigate whether these sources of information can be used to improve accuracy when mapping reads, we developed the RMAP tool, which can map reads having a wide range of lengths and allows base-call quality scores to determine which positions in each read are more important when mapping. We applied RMAP to analyze data re-sequenced from two human BAC regions for varying read lengths, and varying criteria for use of quality scores. RMAP is freely available for downloading at http://rulai.cshl.edu/rmap/. Conclusion Our results indicate that significant gains in Solexa read mapping performance can be achieved by considering the information in 3' ends of longer reads, and appropriately using the base-call quality scores. The RMAP tool we have developed will enable researchers to effectively exploit this information in targeted re-sequencing projects.

Quality Evaluation Scores are no more Reliable than Gestalt in Evaluating the Quality of Emergency Medicine Blogs: A METRIQ Study.

Science.gov (United States)

Thoma, Brent; Sebok-Syer, Stefanie S; Colmers-Gray, Isabelle; Sherbino, Jonathan; Ankel, Felix; Trueger, N Seth; Grock, Andrew; Siemens, Marshall; Paddock, Michael; Purdy, Eve; Kenneth Milne, William; Chan, Teresa M

2018-01-30

Construct: We investigated the quality of emergency medicine (EM) blogs as educational resources. Online medical education resources such as blogs are increasingly used by EM trainees and clinicians. However, quality evaluations of these resources using gestalt are unreliable. We investigated the reliability of two previously derived quality evaluation instruments for blogs. Sixty English-language EM websites that published clinically oriented blog posts between January 1 and February 24, 2016, were identified. A random number generator selected 10 websites, and the 2 most recent clinically oriented blog posts from each site were evaluated using gestalt, the Academic Life in Emergency Medicine (ALiEM) Approved Instructional Resources (AIR) score, and the Medical Education Translational Resources: Impact and Quality (METRIQ-8) score, by a sample of medical students, EM residents, and EM attendings. Each rater evaluated all 20 blog posts with gestalt and 15 of the 20 blog posts with the ALiEM AIR and METRIQ-8 scores. Pearson's correlations were calculated between the average scores for each metric. Single-measure intraclass correlation coefficients (ICCs) evaluated the reliability of each instrument. Our study included 121 medical students, 88 EM residents, and 100 EM attendings who completed ratings. The average gestalt rating of each blog post correlated strongly with the average scores for ALiEM AIR (r = .94) and METRIQ-8 (r = .91). Single-measure ICCs were fair for gestalt (0.37, IQR 0.25-0.56), ALiEM AIR (0.41, IQR 0.29-0.60) and METRIQ-8 (0.40, IQR 0.28-0.59). The average scores of each blog post correlated strongly with gestalt ratings. However, neither ALiEM AIR nor METRIQ-8 showed higher reliability than gestalt. Improved reliability may be possible through rater training and instrument refinement.

Ossification score is a better indicator of maturity related changes in eating quality than animal age.

Science.gov (United States)

Bonny, S P F; Pethick, D W; Legrand, I; Wierzbicki, J; Allen, P; Farmer, L J; Polkinghorne, R J; Hocquette, J-F; Gardner, G E

2016-04-01

Ossification score and animal age are both used as proxies for maturity-related collagen crosslinking and consequently decreases in beef tenderness. Ossification score is strongly influenced by the hormonal status of the animal and may therefore better reflect physiological maturity and consequently eating quality. As part of a broader cross-European study, local consumers scored 18 different muscle types cooked in three ways from 482 carcasses with ages ranging from 590 to 6135 days and ossification scores ranging from 110 to 590. The data were studied across three different maturity ranges; the complete range of maturities, a lesser range and a more mature range. The lesser maturity group consisted of carcasses having either an ossification score of 200 or less or an age of 987 days or less with the remainder in the greater maturity group. The three different maturity ranges were analysed separately with a linear mixed effects model. Across all the data, and for the greater maturity group, animal age had a greater magnitude of effect on eating quality than ossification score. This is likely due to a loss of sensitivity in mature carcasses where ossification approached and even reached the maximum value. In contrast, age had no relationship with eating quality for the lesser maturity group, leaving ossification score as the more appropriate measure. Therefore ossification score is more appropriate for most commercial beef carcasses, however it is inadequate for carcasses with greater maturity such as cull cows. Both measures may therefore be required in models to predict eating quality over populations with a wide range in maturity.

The use of a dietary quality score as a predictor of childhood overweight and obesity.

Science.gov (United States)

Perry, Catherine P; Keane, Eimear; Layte, Richard; Fitzgerald, Anthony P; Perry, Ivan J; Harrington, Janas M

2015-06-24

The use of dietary quality scores/indices to describe diet quality in children has increased in the past decade. However, to date, few studies have focused on the use of these scores on disease outcomes such as childhood obesity and most are developed from detailed dietary assessments. Therefore, the aims of this study were: firstly to construct a diet quality score (DQS) from a brief dietary assessment tool; secondly to examine the association between diet quality and childhood overweight or obesity; thirdly we also aim to examine the associations between individual DQS components and childhood overweight or obesity. A secondary analysis of cross sectional data of a sample of 8,568 9-year-old children and their families as part of the Growing Up in Ireland (GUI) study. Subjects were drawn from a probability proportionate to size sampling of primary schools throughout Ireland over the school year 2007-2008. Height and weight were measured by trained researchers using standardised methods and BMI was classified using the International Obesity Taskforce cut-points. The DQS (un-weighted) was developed using a 20-item, parent reported, food frequency questionnaire of foods consumed over the past 24 h. Adjusted odds ratios for overweight and obesity were examined by DQS quintile, using the first quintile (highest diet quality) as the reference category. The prevalence of normal weight, overweight and obese was 75, 19 and 6% respectively. DQS ranged from -5 to 25, higher scores indicated higher diet quality in the continuous score. In analyses adjusted for gender, parent's education, physical activity and T.V. viewing, child obesity but not overweight was significantly associated with poor diet quality: OR of 1.56 (95% CI 1.02 2.38) in the 5th compared to the 1st DQS quintile. Findings from individual food items were inconsistent. The findings suggest that diet quality may be an important factor in childhood obesity. A simple DQS developed from a short dietary assessment

Interpreting Quality of Life after Brain Injury Scores: Cross-Walk with the Short Form-36.

Science.gov (United States)

Wilson, Lindsay; Marsden-Loftus, Isaac; Koskinen, Sanna; Bakx, Wilbert; Bullinger, Monika; Formisano, Rita; Maas, Andrew; Neugebauer, Edmund; Powell, Jane; Sarajuuri, Jaana; Sasse, Nadine; von Steinbuechel, Nicole; von Wild, Klaus; Truelle, Jean-Luc

2017-01-01

The Quality of Life after Brain Injury (QOLIBRI) instruments are traumatic brain injury (TBI)-specific assessments of health-related quality of life (HRQoL), with established validity and reliability. The purpose of the study is to help improve the interpretability of the two QOLIBRI summary scores (the QOLIBRI Total score and the QOLBRI Overall Scale [OS] score). An analysis was conducted of 761 patients with TBI who took part in the QOLIBRI validation studies. A cross-walk between QOLIBRI scores and the SF-36 Mental Component Summary norm-based scoring system was performed using geometric mean regression analysis. The exercise supports a previous suggestion that QOLIBRI Total scores GOSE), as a measure of global function, are presented in the form of means and standard deviations that allow comparison with other studies, and data on age and sex are presented for the QOLIBRI-OS. While bearing in mind the potential imprecision of the comparison, the findings provide a framework for evaluating QOLIBRI summary scores in relation to generic HRQoL that improves their interpretability.

Ab initio protein structure assembly using continuous structure fragments and optimized knowledge-based force field.

Science.gov (United States)

Xu, Dong; Zhang, Yang

2012-07-01

Ab initio protein folding is one of the major unsolved problems in computational biology owing to the difficulties in force field design and conformational search. We developed a novel program, QUARK, for template-free protein structure prediction. Query sequences are first broken into fragments of 1-20 residues where multiple fragment structures are retrieved at each position from unrelated experimental structures. Full-length structure models are then assembled from fragments using replica-exchange Monte Carlo simulations, which are guided by a composite knowledge-based force field. A number of novel energy terms and Monte Carlo movements are introduced and the particular contributions to enhancing the efficiency of both force field and search engine are analyzed in detail. QUARK prediction procedure is depicted and tested on the structure modeling of 145 nonhomologous proteins. Although no global templates are used and all fragments from experimental structures with template modeling score >0.5 are excluded, QUARK can successfully construct 3D models of correct folds in one-third cases of short proteins up to 100 residues. In the ninth community-wide Critical Assessment of protein Structure Prediction experiment, QUARK server outperformed the second and third best servers by 18 and 47% based on the cumulative Z-score of global distance test-total scores in the FM category. Although ab initio protein folding remains a significant challenge, these data demonstrate new progress toward the solution of the most important problem in the field. Copyright © 2012 Wiley Periodicals, Inc.

Food-based diet quality score in relation to depressive symptoms in young and middle-aged Japanese women.

Science.gov (United States)

Sakai, Hiroka; Murakami, Kentaro; Kobayashi, Satomi; Suga, Hitomi; Sasaki, Satoshi

2017-06-01

Only a few studies have focused on the association between overall diet, rather than intakes of individual nutrients or foods, and depressive symptoms in Japanese. This cross-sectional study examined associations between a diet quality score and depressive symptoms in 3963 young (age 18 years) and 3833 middle-aged (mean age 47·9 (sd 4·2) years) Japanese women. Dietary information was collected using a diet history questionnaire. A previously developed diet quality score was computed mainly based on the Japanese Food Guide Spinning Top. The prevalence of depressive symptoms was 22·0 % for young women and 16·8 % for middle-aged women, assessed as a Center for Epidemiologic Studies Depression (CES-D) score ≥23 and ≥19, respectively. As expected, the diet quality score was associated positively with intakes of 'grain dishes', 'vegetable dishes', 'fish and meat dishes', 'milk' and 'fruits' and inversely with intakes of energy from 'snacks, confection and beverages' and Na from seasonings. After adjustment for potential confounders, OR for depressive symptoms in the highest v. lowest quintiles of the diet quality score was 0·65 (95 % CI 0·50, 0·84) in young women (P for trend=0·0005). In middle-aged women, the corresponding value was 0·59 (95 % CI 0·45, 0·78) (P for trenddiet quality and CES-D scores were treated as continuous variables also showed inverse associations. In conclusion, this cross-sectional study showed that a higher diet quality score was associated with a lower prevalence of depressive symptoms in young and middle-aged Japanese women. Prospective studies are needed to confirm a public health relevance of this finding.

Communication: A benchmark-quality, full-dimensional ab initio potential energy surface for Ar-HOCO

International Nuclear Information System (INIS)

Conte, Riccardo; Bowman, Joel M.; Houston, Paul L.

2014-01-01

A full-dimensional, global ab initio potential energy surface (PES) for the Ar-HOCO system is presented. The PES consists of a previous intramolecular ab initio PES for HOCO [J. Li, C. Xie, J. Ma, Y. Wang, R. Dawes, D. Xie, J. M. Bowman, and H. Guo, J. Phys. Chem. A 116, 5057 (2012)], plus a new permutationally invariant interaction potential based on fitting 12 432 UCCSD(T)-F12a/aVDZ counterpoise-corrected energies. The latter has a total rms fitting error of about 25 cm −1 for fitted interaction energies up to roughly 12 000 cm −1 . Two additional fits are presented. One is a novel very compact permutational invariant representation, which contains terms only involving the Ar-atom distances. The rms fitting error for this fit is 193 cm −1 . The other fit is the widely used pairwise one. The pairwise fit to the entire data set has an rms fitting error of 427 cm −1 . All of these potentials are used in preliminary classical trajectory calculations of energy transfer with a focus on comparisons with the results using the benchmark potential

Communication: A benchmark-quality, full-dimensional ab initio potential energy surface for Ar-HOCO

Energy Technology Data Exchange (ETDEWEB)

Conte, Riccardo, E-mail: riccardo.conte@emory.edu, E-mail: jmbowma@emory.edu; Bowman, Joel M., E-mail: riccardo.conte@emory.edu, E-mail: jmbowma@emory.edu [Department of Chemistry and Cherry L. Emerson Center for Scientific Calculation, Emory University, Atlanta, Georgia 30322 (United States); Houston, Paul L., E-mail: paul.houston@cos.gatech.edu [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2014-04-21

A full-dimensional, global ab initio potential energy surface (PES) for the Ar-HOCO system is presented. The PES consists of a previous intramolecular ab initio PES for HOCO [J. Li, C. Xie, J. Ma, Y. Wang, R. Dawes, D. Xie, J. M. Bowman, and H. Guo, J. Phys. Chem. A 116, 5057 (2012)], plus a new permutationally invariant interaction potential based on fitting 12 432 UCCSD(T)-F12a/aVDZ counterpoise-corrected energies. The latter has a total rms fitting error of about 25 cm{sup −1} for fitted interaction energies up to roughly 12 000 cm{sup −1}. Two additional fits are presented. One is a novel very compact permutational invariant representation, which contains terms only involving the Ar-atom distances. The rms fitting error for this fit is 193 cm{sup −1}. The other fit is the widely used pairwise one. The pairwise fit to the entire data set has an rms fitting error of 427 cm{sup −1}. All of these potentials are used in preliminary classical trajectory calculations of energy transfer with a focus on comparisons with the results using the benchmark potential.

Do employers know the quality of health care benefits they provide? Use of HEDIS depression scores for health plans.

Science.gov (United States)

Robst, John; Rost, Kathryn; Marshall, Donna

2013-11-01

OBJECTIVE Dissemination of health quality measures is a necessary ingredient of efforts to harness market-based forces, such as value-based purchasing by employers, to improve health care quality. This study examined reporting of Healthcare Effectiveness Data and Information Set (HEDIS) measures for depression to firms interested in improving depression care. METHODS During surveys conducted between 2009 and 2011, a sample of 325 employers that were interested in improving depression treatment were asked whether their primary health plan reports HEDIS scores for depression to the National Committee for Quality Assurance (NCQA) and if so, whether they knew the scores. Data about HEDIS reporting by the health plans were collected from the NCQA. RESULTS HEDIS depression scores were reported by the primary health plans of 154 (47%) employers, but only 7% of employers knew their plan's HEDIS scores. Because larger employers were more likely to report knowing the scores, 53% of all employees worked for employers who reported knowing the scores. A number of structural, health benefit, and need characteristics predicted knowledge of HEDIS depression scores by employers. CONCLUSIONS The study demonstrated that motivated employers did not know their depression HEDIS scores even when their plan publicly reported them. Measures of health care quality are not reaching the buyers of insurance products; however, larger employers were more likely to know the HEDIS scores for their health plan, suggesting that value-based purchasing may have some ability to affect health care quality.

Ab initio calculation of intermolecular potentials for dimer Cl_2-Cl_2 and prediction of second virial coefficients

International Nuclear Information System (INIS)

Nguyen Thanh Duoc; Nguyen Thi Ai Nhung; Tran Duong; Pham Van Tat

2015-01-01

The results presented in this paper are the ab initio intermolecular potentials and the second virial coefficient, B_2 (T) of the dimer Cl_2-Cl_2. These ab initio potentials were proposed by the quantum chemical calculations at high level of theory CCSD(T) with basis sets of Dunning valence correlation-consistent aug-cc-pVmZ (m = 2, 3); these results were extrapolated to complete basis set limit aug-cc-pV23Z. The ab initio energies of complete basis set limit aug-cc-pV23Z resulted from the exponential extrapolation were used to construct the 5-site pair potential functions. The second virial coefficients for this dimer were predicted from those with four-dimensional integration. The second virial coefficients were also corrected to first-order quantum effects. The results turn out to be in good agreement with experimental data, if available, or with those from empirical correlation. The quality of ab initio 5-site potentials proved the reliability for prediction of molecular thermodynamic properties. (author)

Plasma ascorbic acid, a priori diet quality score, and incident hypertension

NARCIS (Netherlands)

Buijsse, Brian; Jacobs, D.R.; Steffen, L.M.; Kromhout, Daan; Gross, M.D.

2015-01-01

Vitamin C may reduce risk of hypertension, either in itself or by marking a healthy diet pattern. We assessed whether plasma ascorbic acid and the a priori diet quality score relate to incident hypertension and whether they explain each other's predictive abilities. Data were from 2884 black and

Data from frequency-volume charts versus symptom scores and quality of life score in men with lower urinary tract symptoms due to benign prostatic hyperplasia

NARCIS (Netherlands)

van Venrooij, GEPM; Eckhardt, MD; Gisolf, KWH; Boon, TA

Objective: The aim is to study the relations between reported data on frequency-volume charts and the American Urological Association (AUA) symptom scores and quality of life score. Methods: Males with lower urinary tract symptoms due to benign prostatic hyperplasia (BPH), were consecutively

Ab initio model of porous periclase

International Nuclear Information System (INIS)

Drummond, Neil D.; Swift, Damian C.; Ackland, Graeme J.

2004-01-01

A two-phase equilibrium equation of state (EOS) for periclase (MgO) was constructed using ab initio quantum mechanics, including a rigorous calculation of quasiharmonic phonon modes. Much of the shock wave data reported for periclase is on porous material. We compared the theoretical EOS with porous data using a simple 'snowplough' treatment and also a model using finite equilibration rates suitable for continuum mechanics simulations. (This model has been applied previously to various heterogeneous explosives as well as other porous materials.) The results were consistent and matched the data well at pressures above the regime affected by strength - and ramp-wave formation - during compaction. Ab initio predictions of the response of porous material have been cited recently as a novel and advanced capability; we feel that this is a fairly routine extension to established ab initio techniques

Ab initio derivation of model energy density functionals

International Nuclear Information System (INIS)

Dobaczewski, Jacek

2016-01-01

I propose a simple and manageable method that allows for deriving coupling constants of model energy density functionals (EDFs) directly from ab initio calculations performed for finite fermion systems. A proof-of-principle application allows for linking properties of finite nuclei, determined by using the nuclear nonlocal Gogny functional, to the coupling constants of the quasilocal Skyrme functional. The method does not rely on properties of infinite fermion systems but on the ab initio calculations in finite systems. It also allows for quantifying merits of different model EDFs in describing the ab initio results. (letter)

Highlighting ethical decisions underlying the scoring of animal welfare in the Welfare Quality® scheme

DEFF Research Database (Denmark)

Veissier, I.; Jensen, Karsten Klint; Botreau, R.

2011-01-01

dimension of scoring and labelling does not mean that we should reject them, but it does mean that we need to make the normative and ethical background explicit. The Welfare Quality® scoring system is used as a case study in order to highlight the role of underlying value-based decisions. In this scoring......, but the rules governing the assignment of an animal unit to a category take into account what had been observed on European farms. The scientists behind Welfare Quality® are keen to make the value-based choices underlying assessments of animal welfare transparent. This is essential to allow stakeholder groups......All systems of scoring animal units (groups, farms, slaughter plants, etc.) according to the level of the animals’ welfare are based inevitably on normative decisions. Similarly, all methods of labelling, in terms of acceptability, are based on choices reflecting ethical values. The evaluative...

Speed-up of ab initio hybrid Monte Carlo and ab initio path integral hybrid Monte Carlo simulations by using an auxiliary potential energy surface

International Nuclear Information System (INIS)

Nakayama, Akira; Taketsugu, Tetsuya; Shiga, Motoyuki

2009-01-01

Efficiency of the ab initio hybrid Monte Carlo and ab initio path integral hybrid Monte Carlo methods is enhanced by employing an auxiliary potential energy surface that is used to update the system configuration via molecular dynamics scheme. As a simple illustration of this method, a dual-level approach is introduced where potential energy gradients are evaluated by computationally less expensive ab initio electronic structure methods. (author)

Improving iris recognition performance using segmentation, quality enhancement, match score fusion, and indexing.

Science.gov (United States)

Vatsa, Mayank; Singh, Richa; Noore, Afzel

2008-08-01

This paper proposes algorithms for iris segmentation, quality enhancement, match score fusion, and indexing to improve both the accuracy and the speed of iris recognition. A curve evolution approach is proposed to effectively segment a nonideal iris image using the modified Mumford-Shah functional. Different enhancement algorithms are concurrently applied on the segmented iris image to produce multiple enhanced versions of the iris image. A support-vector-machine-based learning algorithm selects locally enhanced regions from each globally enhanced image and combines these good-quality regions to create a single high-quality iris image. Two distinct features are extracted from the high-quality iris image. The global textural feature is extracted using the 1-D log polar Gabor transform, and the local topological feature is extracted using Euler numbers. An intelligent fusion algorithm combines the textural and topological matching scores to further improve the iris recognition performance and reduce the false rejection rate, whereas an indexing algorithm enables fast and accurate iris identification. The verification and identification performance of the proposed algorithms is validated and compared with other algorithms using the CASIA Version 3, ICE 2005, and UBIRIS iris databases.

Patients with tattoo reactions have reduced quality of life and suffer from itch: Dermatology Life Quality Index and Itch Severity Score measurements.

Science.gov (United States)

Hutton Carlsen, K; Serup, J

2015-02-01

Tattoos are a trend with increasing side-effects. The burden of local reaction with swelling, itching and discomfort may impel sufferers to consult medical assistance. To assess tattoo reactions and their influence on quality of life and itching by utilizing the Dermatology Life Quality Index (DLQI) scoring system and Itch Severity Scale (ISS). Patients attending the 'Tattoo Clinic' at Bispebjerg University Hospital, Denmark with tattoo problems spanning more than 3 months were invited. Forty patients participated during September-November 2012. Patients attending their routine consultations completed the ISS and DLQI questionnaires. Patients with tattoo reactions experienced reduced quality of life, DLQI score 7.4 and were burdened by itch, ISS score 7.2. Both DLQI and ISS results attained the level of discomfort of known skin diseases such as psoriasis, pruritus and eczema albeit the typical tattooed affected areas are smaller. Sufferers of tattoo reactions have reduced quality of life and are often burdened by itching attaining the level of other cumbersome afflictions recognized as dermatological diseases associated with itch. Tattoo reactions warrant diagnosis and treatment with same professional intent shared with other skin diseases. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

An ab initio molecular

Indian Academy of Sciences (India)

mechanisms of two molecular crystals: An ab initio molecular dynamics ... for Computation in Molecular and Materials Science and Department of Chemistry, School of ..... NSAF Foundation of National Natural Science Foun- ... Matter 14 2717.

Ab initio and Gordon--Kim intermolecular potentials for two nitrogen molecules

International Nuclear Information System (INIS)

Ree, F.H.; Winter, N.W.

1980-01-01

Both ab initio MO--LCAO--SCF and the electron-gas (or Gordon--Kim) methods have been used to compute the intermolecular potential (Phi) of N 2 molecules for seven different N 2 --N 2 orientations. The ab initio calculations were carried out using a [4s3p] contracted Gaussian basis set with and without 3d polarization functions. The larger basis set provides adequate results for Phi>0.002 hartree or intermolecular separations less than 6.5--7 bohr. We use a convenient analytic expression to represent the ab initio data in terms of the intermolecular distance and three angles defining the orientations of the two N 2 molecules. The Gordon--Kim method with Rae's self-exchange correction yields Phi, which agrees reasonably well over a large repulsive range. However, a detailed comparison of the electron kinetic energy contributions shows a large difference between the ab initio and the Gordon--Kim calculations. Using the ab initio data we derive an atom--atom potential of the two N 2 molecules. Although this expression does not accurately fit the data at some orientations, its spherical average agrees with the corresponding average of the ab initio Phi remarkably well. The spherically averaged ab initio Phi is also compared with the corresponding quantities derived from experimental considerations. The approach of the ab initio Phi to the classical quadrupole--quadrupole interaction at large intermolecular separation is also discussed

Depression, anxiety and quality of life scores in seniors after an endurance exercise program

Directory of Open Access Journals (Sweden)

Antunes Hanna Karen Moreira

2005-01-01

Full Text Available OBJECTIVE: Mood disorders are a frequent problem in old age, and their symptoms constitute an important public health issue. These alterations affect the quality of life mainly by restricting social life. The participation in a regular exercise program is an effective way of reducing or preventing the functional decline associated with aging. The aim of the present study was to examine the effects of fitness-endurance activity (at the intensity of Ventilatory Threshold 1 (VT-1 in depression, anxiety and quality of life scores in seniors. METHODS: The study involved 46 sedentary seniors aged 60-75 (66.97 ± 4.80 who were randomly allocated to two groups: 1 Control group, which was neither asked to vary their everyday activities nor to join a regular physical fitness program; and 2 Experimental group, whose members took part in an aerobic fitness program consisting of ergometer cycle sessions 3 times a week on alternate days for six months working at a heart rate corresponding to ventilatory threshold (VT-1 intensity. Subjects were submitted to a basal evaluation using the geriatric depression screening scale - GDS, STAI trait/state (anxiety scale and SF-36 (quality of life scale. RESULTS: Comparing the groups after the study period, we found a significant decrease in depressive and anxiety scores and an improvement in the quality of life in the experimental group, but no significant changes in the control group. CONCLUSION: The data suggest that an aerobic exercise program at VT-1 intensity suffices to promote favorable modifications in depressive and anxiety scores to improve the quality of life in seniors.

Ab initio valence calculations in chemistry

CERN Document Server

Cook, D B

1974-01-01

Ab Initio Valence Calculations in Chemistry describes the theory and practice of ab initio valence calculations in chemistry and applies the ideas to a specific example, linear BeH2. Topics covered include the Schrödinger equation and the orbital approximation to atomic orbitals; molecular orbital and valence bond methods; practical molecular wave functions; and molecular integrals. Open shell systems, molecular symmetry, and localized descriptions of electronic structure are also discussed. This book is comprised of 13 chapters and begins by introducing the reader to the use of the Schrödinge

Bicanonical ab Initio Molecular Dynamics for Open Systems.

Science.gov (United States)

Frenzel, Johannes; Meyer, Bernd; Marx, Dominik

2017-08-08

Performing ab initio molecular dynamics simulations of open systems, where the chemical potential rather than the number of both nuclei and electrons is fixed, still is a challenge. Here, drawing on bicanonical sampling ideas introduced two decades ago by Swope and Andersen [ J. Chem. Phys. 1995 , 102 , 2851 - 2863 ] to calculate chemical potentials of liquids and solids, an ab initio simulation technique is devised, which introduces a fictitious dynamics of two superimposed but otherwise independent periodic systems including full electronic structure, such that either the chemical potential or the average fractional particle number of a specific chemical species can be kept constant. As proof of concept, we demonstrate that solvation free energies can be computed from these bicanonical ab initio simulations upon directly superimposing pure bulk water and the respective aqueous solution being the two limiting systems. The method is useful in many circumstances, for instance for studying heterogeneous catalytic processes taking place on surfaces where the chemical potential of reactants rather than their number is controlled and opens a pathway toward ab initio simulations at constant electrochemical potential.

Translation and validation of the Danish version of the postoperative quality of recovery score QoR-15

DEFF Research Database (Denmark)

Kleif, J; Edwards, H M; Sort, R

2015-01-01

.12 to -0.43, P half reliability was 0.90 and 0.88. Test-retest reliability was 0.99 (95% CI: 0......BACKGROUND: Patient perceived quality of recovery is an important outcome after surgery and should be measured in clinical trials. Quality of recovery after surgery and general anaesthesia can be measured by the QoR-15. A high score indicates a good recovery and the score ranges from 0 to 150...

Oral health-related quality-of-life scores differ by socioeconomic status and caries experience.

Science.gov (United States)

Chaffee, Benjamin W; Rodrigues, Priscila Humbert; Kramer, Paulo Floriani; Vítolo, Márcia Regina; Feldens, Carlos Alberto

2017-06-01

(i) Quantify the relative association between child dental caries experience and maternal-reported child oral health-related quality of life (OHRQoL); (ii) examine whether that association differed according to family socioeconomic status (SES); and (iii) explore whether absolute OHRQoL varied by family SES at similar levels of child caries experience. This study was a cross-sectional analysis of children in southern Brazil (n=456, mean age: 38 months) participating in an existing health centre-based intervention study. OHRQoL impact was quantified as mean score on the Brazilian Early Childhood Oral Health Impact Scale (ECOHIS) and compared over categories of caries experience (dmft: 0, dmft: 1-4, dmft: ≥5). Adjusted ECOHIS ratios between caries categories were calculated using regression modelling, overall and within socioeconomic strata defined by maternal education, social class and household income. Caries prevalence (dmft >0) was 39.7%, mean ECOHIS score was 2.0 (SD: 3.5), and 44.3% of mothers reported OHRQoL impact (ECOHIS score >0). Increasing child caries experience was associated with worsening child and family quality of life: ECOHIS scores were 3.0 times greater (95% CI: 2.0, 4.4) for children with dmft ≥5 vs dmft=0, a pattern that persisted regardless of family socioeconomic status (P for interaction: all >0.3). However, adjusted for dental status and sociodemographic characteristics, mean ECOHIS scores were lower when reported by mothers of less educational attainment (ratio: 0.7; 95% CI: 0.5, 1.0), lower social class (ratio: 0.7; 95% CI: 0.5, 1.0) or in lower income households (ratio: 0.8; 95% CI: 0.6, 1.3). Dental caries was associated with negative child and family experiences and lower OHRQoL across all social groups; yet, families facing greater disadvantage may report lesser quality-of-life impact at the same level of disease experience. Thus, subjective quality-of-life measures may differ under varying social contexts, with possible

Application of a simple, affordable quality metric tool to colorectal, upper gastrointestinal, hernia, and hepatobiliary surgery patients: the HARM score.

Science.gov (United States)

Brady, Justin T; Ko, Bona; Hohmann, Samuel F; Crawshaw, Benjamin P; Leinicke, Jennifer A; Steele, Scott R; Augestad, Knut M; Delaney, Conor P

2018-06-01

Quality is the major driver for both clinical and financial assessment. There remains a need for simple, affordable, quality metric tools to evaluate patient outcomes, which led us to develop the HospitAl length of stay, Readmission and Mortality (HARM) score. We hypothesized that the HARM score would be a reliable tool to assess patient outcomes across various surgical specialties. From 2011 to 2015, we identified colorectal, hepatobiliary, upper gastrointestinal, and hernia surgery admissions using the Vizient Clinical Database. Individual and hospital HARM scores were calculated from length of stay, 30-day readmission, and mortality rates. We evaluated the correlation of HARM scores with complication rates using the Clavien-Dindo classification. We identified 525,083 surgical patients: 206,981 colorectal, 164,691 hepatobiliary, 97,157 hernia, and 56,254 upper gastrointestinal. Overall, 53.8% of patients were admitted electively with a mean HARM score of 2.24; 46.2% were admitted emergently with a mean HARM score of 1.45 (p  4 (p  4, complication rates were 9.3, 23.2, 38.8, and 71.6%, respectively. There was a similar trend for increasing HARM score in emergent admissions as well. For all surgical procedure categories, increasing HARM score, with and without risk adjustment, correlated with increasing severity of complications by Clavien-Dindo classification. The HARM score is an easy-to-use quality metric that correlates with increasing complication rates and complication severity across multiple surgical disciplines when evaluated on a large administrative database. This inexpensive tool could be adopted across multiple institutions to compare the quality of surgical care.

Complications among colorectal cancer survivors: SF-6D preference-weighted quality of life scores.

Science.gov (United States)

Hornbrook, Mark C; Wendel, Christopher S; Coons, Stephen Joel; Grant, Marcia; Herrinton, Lisa J; Mohler, M Jane; Baldwin, Carol M; McMullen, Carmit K; Green, Sylvan B; Altschuler, Andrea; Rawl, Susan M; Krouse, Robert S

2011-03-01

Societal preference-weighted health-related quality of life (HRQOL) scores enable comparing multidimensional health states across diseases and treatments for research and policy. To assess the effects of living with a permanent intestinal stoma, compared with a major bowel resection, among colorectal cancer (CRC) survivors. Cross-sectional multivariate linear regression analysis to explain preference-weighted HRQOL scores. In all, 640 CRC survivors (≥ 5 years) from 3 group model health maintenance organizations; ostomates and nonostomates with colorectal resections for CRC were matched on gender, age (± 5 years), time since diagnosis, and tumor site (rectum vs. colon). SF-6D scoring system was applied to Medical Outcomes Study Short Form-36 version 2 (SF-36v2); City of Hope Quality of Life-Ostomy; and Charlson-Deyo comorbidity index. Survey of CRC survivors linked to respondents' clinical data extracted from health maintenance organization files. Response rate was 52%. Ostomates and nonostomates had similar sociodemographic characteristics. Mean SF-6D score was 0.69 for ostomates, compared with 0.73 for nonostomates (P ostomy after other factors were taken into account. Surgical complications, comorbidities, and metastatic disease lowered the preference-weighted HRQOL of CRC survivors with and without ostomies. Further research to understand and reduce late complications from CRC surgeries as well as associated depression is warranted.

Ab-initio ZORA calculations

NARCIS (Netherlands)

Faas, S.; Snijders, Jaap; van Lenthe, J.H.; HernandezLaguna, A; Maruani, J; McWeeny, R; Wilson, S

2000-01-01

In this paper we present the first application of the ZORA (Zeroth Order Regular Approximation of the Dirac Fock equation) formalism in Ab Initio electronic structure calculations. The ZORA method, which has been tested previously in the context of Density Functional Theory, has been implemented in

A Prototype Public Speaking Skills Assessment: An Evaluation of Human-Scoring Quality. Research Report. ETS RR-15-36

Science.gov (United States)

Joe, Jilliam; Kitchen, Christopher; Chen, Lei; Feng, Gary

2015-01-01

The purpose of this paper is to summarize the evaluation of human-scoring quality for an assessment of public speaking skills. Videotaped performances given by 17 speakers on 4 tasks were scored by expert and nonexpert raters who had extensive experience scoring performance-based and constructed-response assessments. The Public Speaking Competence…

Integration of QUARK and I-TASSER for Ab Initio Protein Structure Prediction in CASP11.

Science.gov (United States)

Zhang, Wenxuan; Yang, Jianyi; He, Baoji; Walker, Sara Elizabeth; Zhang, Hongjiu; Govindarajoo, Brandon; Virtanen, Jouko; Xue, Zhidong; Shen, Hong-Bin; Zhang, Yang

2016-09-01

We tested two pipelines developed for template-free protein structure prediction in the CASP11 experiment. First, the QUARK pipeline constructs structure models by reassembling fragments of continuously distributed lengths excised from unrelated proteins. Five free-modeling (FM) targets have the model successfully constructed by QUARK with a TM-score above 0.4, including the first model of T0837-D1, which has a TM-score = 0.736 and RMSD = 2.9 Å to the native. Detailed analysis showed that the success is partly attributed to the high-resolution contact map prediction derived from fragment-based distance-profiles, which are mainly located between regular secondary structure elements and loops/turns and help guide the orientation of secondary structure assembly. In the Zhang-Server pipeline, weakly scoring threading templates are re-ordered by the structural similarity to the ab initio folding models, which are then reassembled by I-TASSER based structure assembly simulations; 60% more domains with length up to 204 residues, compared to the QUARK pipeline, were successfully modeled by the I-TASSER pipeline with a TM-score above 0.4. The robustness of the I-TASSER pipeline can stem from the composite fragment-assembly simulations that combine structures from both ab initio folding and threading template refinements. Despite the promising cases, challenges still exist in long-range beta-strand folding, domain parsing, and the uncertainty of secondary structure prediction; the latter of which was found to affect nearly all aspects of FM structure predictions, from fragment identification, target classification, structure assembly, to final model selection. Significant efforts are needed to solve these problems before real progress on FM could be made. Proteins 2016; 84(Suppl 1):76-86. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Residue contacts predicted by evolutionary covariance extend the application of ab initio molecular replacement to larger and more challenging protein folds

Directory of Open Access Journals (Sweden)

Felix Simkovic

2016-07-01

Full Text Available For many protein families, the deluge of new sequence information together with new statistical protocols now allow the accurate prediction of contacting residues from sequence information alone. This offers the possibility of more accurate ab initio (non-homology-based structure prediction. Such models can be used in structure solution by molecular replacement (MR where the target fold is novel or is only distantly related to known structures. Here, AMPLE, an MR pipeline that assembles search-model ensembles from ab initio structure predictions (`decoys', is employed to assess the value of contact-assisted ab initio models to the crystallographer. It is demonstrated that evolutionary covariance-derived residue–residue contact predictions improve the quality of ab initio models and, consequently, the success rate of MR using search models derived from them. For targets containing β-structure, decoy quality and MR performance were further improved by the use of a β-strand contact-filtering protocol. Such contact-guided decoys achieved 14 structure solutions from 21 attempted protein targets, compared with nine for simple Rosetta decoys. Previously encountered limitations were superseded in two key respects. Firstly, much larger targets of up to 221 residues in length were solved, which is far larger than the previously benchmarked threshold of 120 residues. Secondly, contact-guided decoys significantly improved success with β-sheet-rich proteins. Overall, the improved performance of contact-guided decoys suggests that MR is now applicable to a significantly wider range of protein targets than were previously tractable, and points to a direct benefit to structural biology from the recent remarkable advances in sequencing.

Evaluation of Diabetes Quality of Care Based on a Care Scoring System among People Referring to Diabetes Clinic in Ardabil, 2014

Directory of Open Access Journals (Sweden)

J Ataei

2015-06-01

Full Text Available Background & objectives: Successful implementation of diabetes care can reduce acute and chronic complications of diabetes. This study was conducted to evaluate the quality of care according to a care scoring system among people with type 2 diabetes referring to the diabetes clinic in Ardabil. Methods: This cross sectional study was conducted in 2014 and a total of 300 people with type 2 diabetes in age range of 20-70 years old were included via convenience sampling. Data were collected by an interviewer using a structured questionnaire and checklist. Each patient was classified according to a quality of care scoring system into 3 categories: ≤10, 15-20, >20. Statistical analysis performed by SPSS v.20 software and descriptive analysis used to display data as frequency tables and graphs. Analytical tests such as ANOVA, Kruskal-Wallis, Chi squared, and fisher exact test were also used to analyze the data. Results: The mean age of patients was 54.13 ± 9.13 and the majority of them were women (72.3%. The mean of BMI and HbA1c was 29.58 ± 4.77 and 8.93± 2.13, respectively. The mean of FBS was 191.18 ± 84.23 and the average length of disease was 7.74±5.89 years. The mean of quality of care score among participants was 23.20±9.99. About one-third of patients (29.7% had a quality care score ≤10, half of them (51% had a score between 15-20, and only 19.35% had a score >20. There was an association between HbA1c, FBS, diastolic blood pressure, cholesterol and LDL with a quality of care score which was statistically significant (p<0.05. Conclusion: In this study there was a gap between the current quality of care of patients and recommended standards. Therefore in order to minimize the current barriers and problems it is recommended to implement an effective interventional program. In addition, using a quality care scoring system is a rapid, easy and valid method for evaluating diabetes quality of care.

High Framingham risk score decreases quality of life in adults

Directory of Open Access Journals (Sweden)

Christian Yosaputra

2010-04-01

Full Text Available Cardiovascular disease (CVD risk factors, such as diabetes, hypertension, hypercholesterolemia, smoking, and obesity tend to occur together in the general population. Increasing prevalence of multiple CVD risk factors has been related to increased risk of death from coronary heart disease and stroke. Studies have suggested that people with several risk factors of CVD may have impaired health-related quality of life. The objective of this study was to assess the association of CVD risk factors with quality of life (QOL among adults aged 40 to 65 years. A cross-sectional study was conducted involving 220 subjects 40 - 65 years of age at a health center. The CVD risk factors were assessed using the Framingham risk score that is the standard instrument for assessment of the risk of a first cardiac event. The risk factors assessed were age, smoking, blood pressure, total cholesterol and high density lipoprotein cholesterol concentrations. QOL was assessed by means of the WHOQOL-BREF instrument that had been prevalidated. The results of the study showed that 28.2% of subjects were smokers, 56.4% had stage 1 hypertension, 42.8% high total cholesterol and 13.6% low HDL cholesterol. The high risk group amounted to 45.5% and 42.3% constitued an intermediate risk group. High CVD risk scores were significantly associated with a low QOL for all domains (physical, psychological, social and environment (p=0.000. Preventing or reducing the multiple CVD risk factors to improve QOL is necessary among adults.

Ab Initio Calculation of Hyperfine Interaction Parameters: Recent Evolutions, Recent Examples

International Nuclear Information System (INIS)

Cottenier, Stefaan; Vanhoof, Veerle; Torumba, Doru; Bellini, Valerio; Cakmak, Mehmet; Rots, Michel

2004-01-01

For some years already, ab initio calculations based on Density Functional Theory (DFT) belong to the toolbox of the field of hyperfine interaction studies. In this paper, the standard ab initio approach is schematically sketched. New features, methods and possibilities that broke through during the past few years are listed, and their relation to the standard approach is explained. All this is illustrated by some highlights of recent ab initio work done by the Nuclear Condensed Matter Group at the K.U.Leuven.

Highly scalable Ab initio genomic motif identification

KAUST Repository

Marchand, Benoit; Bajic, Vladimir B.; Kaushik, Dinesh

2011-01-01

We present results of scaling an ab initio motif family identification system, Dragon Motif Finder (DMF), to 65,536 processor cores of IBM Blue Gene/P. DMF seeks groups of mutually similar polynucleotide patterns within a set of genomic sequences and builds various motif families from them. Such information is of relevance to many problems in life sciences. Prior attempts to scale such ab initio motif-finding algorithms achieved limited success. We solve the scalability issues using a combination of mixed-mode MPI-OpenMP parallel programming, master-slave work assignment, multi-level workload distribution, multi-level MPI collectives, and serial optimizations. While the scalability of our algorithm was excellent (94% parallel efficiency on 65,536 cores relative to 256 cores on a modest-size problem), the final speedup with respect to the original serial code exceeded 250,000 when serial optimizations are included. This enabled us to carry out many large-scale ab initio motiffinding simulations in a few hours while the original serial code would have needed decades of execution time. Copyright 2011 ACM.

Ab initio calculation of the shear viscosity of neon in the liquid and hypercritical state over a wide pressure and temperature range

Science.gov (United States)

Eggenberger, Rolf; Gerber, Stefan; Huber, Hanspeter; Searles, Debra; Welker, Marc

1992-08-01

The shear viscosity is calculated ab initio for the liquid and hypercritical state, i.e. a previously published potential for Ne 2, obtained from ab initio calculations including electron correlation, is used in classical equilibrium molecular dynamics simulations to obtain the shear viscosity from a Green-Kubo integral. The quality of the results is quite uniform over a large pressure range up to 1000 MPa and a wide temperature range from 26 to 600 K. In most cases the calculated shear viscosity deviates by less than 10% from the experimental value, in general the error being only a few percent.

Multiple time step integrators in ab initio molecular dynamics

International Nuclear Information System (INIS)

Luehr, Nathan; Martínez, Todd J.; Markland, Thomas E.

2014-01-01

Multiple time-scale algorithms exploit the natural separation of time-scales in chemical systems to greatly accelerate the efficiency of molecular dynamics simulations. Although the utility of these methods in systems where the interactions are described by empirical potentials is now well established, their application to ab initio molecular dynamics calculations has been limited by difficulties associated with splitting the ab initio potential into fast and slowly varying components. Here we present two schemes that enable efficient time-scale separation in ab initio calculations: one based on fragment decomposition and the other on range separation of the Coulomb operator in the electronic Hamiltonian. We demonstrate for both water clusters and a solvated hydroxide ion that multiple time-scale molecular dynamics allows for outer time steps of 2.5 fs, which are as large as those obtained when such schemes are applied to empirical potentials, while still allowing for bonds to be broken and reformed throughout the dynamics. This permits computational speedups of up to 4.4x, compared to standard Born-Oppenheimer ab initio molecular dynamics with a 0.5 fs time step, while maintaining the same energy conservation and accuracy

Modeling Disordered Materials with a High Throughput ab-initio Approach

Science.gov (United States)

2015-11-13

Modeling Disordered Materials with a High Throughput ab - initio Approach Kesong Yang,1 Corey Oses,2 and Stefano Curtarolo3, 4 1Department of...J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B 54, 11169–11186 (1996

Embedded atom approach for gold–silicon system from ab initio

Indian Academy of Sciences (India)

In the present paper, an empirical embedded atom method (EAM) potential for gold–silicon (Au–Si) is developed by fitting to ab initio force (the 'force matching' method) and experimental data. The force database is generated within ab initio molecular dynamics (AIMD). The database includes liquid phase at various ...

The Image Quality of a Digital Chest X-Ray Radiography System: Comparison of Quantitative Image Quality Analysis and Radiologists' Visual Scoring

Energy Technology Data Exchange (ETDEWEB)

Nam, Ji Ho [Dept. of Radiology Oncology, Yongsan Hospital, Pusan National University College of Medicine, Yongsan (Korea, Republic of); Chung, Myung Jin [Dept. of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Park, Darl; Kim, Won Taek; Kim, Yong Ho; Ki, Yong Kan; Kim, DFong Hyun; Lee, Ju Hee; Kim, Dong Won [Dept. of Radiology Oncology, Yongsan Hospital, Pusan National University College of Medicine, Yongsan (Korea, Republic of); Jeon, Ho Sang [Reserach Institue for Convergence of Biomedical Science and Technology, Yongsan Hospital, Pusan National University College of Medicine, Yongsan (Korea, Republic of)

2011-11-15

To evaluate the performance of imaging devices, which should be periodically monitored to maintain high quality images to the radiologists. Additionally, this evaluation may prevent patients from radiation over-exposure. The most suitable engineering standard for imaging performance evaluation of digital X-ray thoracic images was determined. IEC 62220-1 standards were used to evaluate the performance of the images. In succession, the visibilities of overall image, pneumothorax, and humerus head in anthropomorphic thoracic phantom images were used to evaluate the image qualities by radiologists. The rank correlation coefficient (p) of visual scoring by radiologists with system spatial resolution is not meaningful (p-value, p = 0.295), but is significant with image noise (p-value, p -0.9267). Finally, the noise equivalent quanta (NEQ) presents a high rank correlation for visual scoring of radiologists (p-value, p = 0.9320). Image quality evaluation of radiologists were mainly affected by imaging noise. Hence, the engineered standard for evaluating image noise is the most important index to effectively monitor the performance of X-ray images. Additionally, the NEQ can be used to evaluate the performance of radiographic systems, because it theoretically corresponds to the synthetic image quality of systems.

Validation of the Six Sigma Z-score for the quality assessment of clinical laboratory timeliness.

Science.gov (United States)

Ialongo, Cristiano; Bernardini, Sergio

2018-03-28

The International Federation of Clinical Chemistry and Laboratory Medicine has introduced in recent times the turnaround time (TAT) as mandatory quality indicator for the postanalytical phase. Classic TAT indicators, namely, average, median, 90th percentile and proportion of acceptable test (PAT), are in use since almost 40 years and to date represent the mainstay for gauging the laboratory timeliness. In this study, we investigated the performance of the Six Sigma Z-score, which was previously introduced as a device for the quantitative assessment of timeliness. A numerical simulation was obtained modeling the actual TAT data set using the log-logistic probability density function. Five thousand replicates for each size of the artificial TAT random sample (n=20, 50, 250 and 1000) were generated, and different laboratory conditions were simulated manipulating the PDF in order to generate more or less variable data. The Z-score and the classic TAT indicators were assessed for precision (%CV), robustness toward right-tailing (precision at different sample variability), sensitivity and specificity. Z-score showed sensitivity and specificity comparable to PAT (≈80% with n≥250), but superior precision that ranged within 20% by moderately small sized samples (n≥50); furthermore, Z-score was less affected by the value of the cutoff used for setting the acceptable TAT, as well as by the sample variability that reflected into the magnitude of right-tailing. The Z-score was a valid indicator of laboratory timeliness and a suitable device to improve as well as to maintain the achieved quality level.

Quantifying radioxerostomia: salivary flow rate, examiner's score, and quality of life questionnaire

International Nuclear Information System (INIS)

Al-Nawas, B.; Al-Nawas, K.; Kunkel, M.; Groetz, K.A.

2006-01-01

Background and purpose: salivary flow rates alone are not sufficient to quantify all aspects of radioxerostomia. This is a problem in studies aiming to reduce radioxerostomia. The aim of this study was to evaluate the association between objectively measured salivary flow rate and subjective xerostomia ratings by the physician (RTOG scale) or the patients (quality of life [QoL] questionnaire). Patients and methods: in a case-control study patients who underwent recall for oral cancer were screened. Inclusion criteria for this diagnostic, noninterventional study were: history of oral carcinoma, surgical and radiation therapy, time interval from start of radiation therapy > 90 days, salivary glands within the radiation field. The control group consisted of patients, who had not received radiotherapy. RTOG salivary gland score, quality of life (EORTC QLQ-C30 and H and N35), and sialometry were recorded. Results: patients with RTOG score 0 had mean salivary flow rates of 0.3 ml/min, those with RTOG 1 0.12 ml/min, RTOG 2 0.02 ml/min, and RTOG 3 < 0.01 ml/min. RTOG score 4 (total fibrosis) did not occur. Based on salivary flow rates, all patients were grouped into xerostomia < 0.2 ml/min (30 patients) and nonxerostomia (twelve patients). QoL results revealed significant differences between patients with xerostomia and nonxerostomia for physical function, dyspnea, swallowing, social eating, dry mouth, nutritional support, and a tendency to higher values for appetite loss. Conclusion: the correlation between ''subjective'' QoL parameters and salivary flow was confirmed. The different subjective aspects of radioxerostomia seem to be better differentiated by the EORTC QoL questionnaire. (orig.)

Patients' experiences of the quality of long-term care among the elderly: comparing scores over time

Directory of Open Access Journals (Sweden)

Zuidgeest Marloes

2012-01-01

Full Text Available Abstract Background Every two years, long-term care organizations for the elderly are obliged to evaluate and publish the experiences of residents, representatives of psychogeriatric patients, and/or assisted-living clients with regard to quality of care. Our hypotheses are that publication of this quality information leads to improved performance, and that organizations with substandard performance will improve more than those whose performance is relatively good. Methods The analyses included organizational units that measured experiences twice between 2007 (t0 and 2009 (t1. Experiences with quality of care were measured with Consumer Quality Index (CQI questionnaires. Besides descriptive analyses (i.e. mean, 5th and 95th percentile, and 90% central range of the 19 CQI indicators and change scores of these indicators were calculated. Differences across five performance groups (ranging from 'worst' to 'best' were tested using an ANOVA test and effect sizes were measured with omega squared (ω2. Results At t0 experiences of residents, representatives, and assisted-living clients were positive on all indicators. Nevertheless, most CQI indicators had improved scores (up to 0.37 change score at t1. Only three indicators showed a minor decline (up to -0.08 change score. Change scores varied between indicators and questionnaires, e.g. they were more profound for the face-to-face interview questionnaire for residents in nursing homes than for the other two mail questionnaires (0.15 vs. 0.05 and 0.04, respectively, possibly due to more variation between nursing homes on the first measurement, perhaps indicating more potential for improvement. A negative relationship was found between prior performance and change, particularly with respect to the experiences of residents (ω2 = 0.16 and assisted-living clients (ω2 = 0.15. However, the relation between prior performance and improvement could also be demonstrated with respect to the experiences reported

Summation of Parquet diagrams as an ab initio method in nuclear structure calculations

International Nuclear Information System (INIS)

Bergli, Elise; Hjorth-Jensen, Morten

2011-01-01

Research highlights: → We present a Green's function based approach for doing ab initio nuclear structure calculations. → In particular the sum the subset of so-called Parquet diagrams. → Applying the theory to a simple but realistic model, results in good agreement with other ab initio methods. → This opens up for ab initio calculations for medium-heavy nuclei. - Abstract: In this work we discuss the summation of the Parquet class of diagrams within Green's function theory as a possible framework for ab initio nuclear structure calculations. The theory is presented and some numerical details are discussed, in particular the approximations employed. We apply the Parquet method to a simple model, and compare our results with those from an exact solution. The main conclusion is that even at the level of approximation presented here, the results shows good agreement with other comparable ab initio approaches.

Reliability and Validity of SERVQUAL Scores Used To Evaluate Perceptions of Library Service Quality.

Science.gov (United States)

Thompson, Bruce; Cook, Colleen

Research libraries are increasingly supplementing collection counts with perceptions of service quality as indices of status and productivity. The present study was undertaken to explore the reliability and validity of scores from the SERVQUAL measurement protocol (A. Parasuraman and others, 1991), which has previously been used in this type of…

Towards hydrogen metallization: an Ab initio approach; Vers la metallisation de l`hydrogene: approche AB initio

Energy Technology Data Exchange (ETDEWEB)

Bernard, St

1998-12-31

The quest for metallic hydrogen is a major goal for both theoretical and experimental condensed matter physics. Hydrogen and deuterium have been compressed up to 200 GPa in diamond anvil cells, without any clear evidence for a metallic behaviour. Loubeyere has recently suggested that hydrogen could metallize, at pressures within experimental range, in a new Van der Waals compound: Ar(H{sub 2}){sub 2} which is characterized at ambient pressure by an open and anisotropic sublattice of hydrogen molecules, stabilized by an argon skeleton. This thesis deals with a detailed ab initio investigation, by Car-Parrinello molecular dynamics methods, of the evolution under pressure of this compound. In a last chapter, we go to much higher pressures and temperatures, in order to compare orbital and orbital free ab initio methods for the dense hydrogen plasma. (author) 109 refs.

Towards hydrogen metallization: an Ab initio approach; Vers la metallisation de l`hydrogene: approche AB initio

Energy Technology Data Exchange (ETDEWEB)

Bernard, St

1999-12-31

The quest for metallic hydrogen is a major goal for both theoretical and experimental condensed matter physics. Hydrogen and deuterium have been compressed up to 200 GPa in diamond anvil cells, without any clear evidence for a metallic behaviour. Loubeyere has recently suggested that hydrogen could metallize, at pressures within experimental range, in a new Van der Waals compound: Ar(H{sub 2}){sub 2} which is characterized at ambient pressure by an open and anisotropic sublattice of hydrogen molecules, stabilized by an argon skeleton. This thesis deals with a detailed ab initio investigation, by Car-Parrinello molecular dynamics methods, of the evolution under pressure of this compound. In a last chapter, we go to much higher pressures and temperatures, in order to compare orbital and orbital free ab initio methods for the dense hydrogen plasma. (author) 109 refs.

Ab initio potential for solids

DEFF Research Database (Denmark)

Chetty, N.; Stokbro, Kurt; Jacobsen, Karsten Wedel

1992-01-01

. At the most approximate level, the theory is equivalent to the usual effective-medium theory. At all levels of approximation, every term in the total-energy expression is calculated ab initio, that is, without any fitting to experiment or to other calculations. Every step in the approximation procedure can...

Association between diet-quality scores, adiposity, total cholesterol and markers of nutritional status in european adults: Findings from the Food4Me study

NARCIS (Netherlands)

Fallaize, R.; Livingstone, K.M.; Celis-Morales, C.; Macready, A.L.; San-Cristobal, R.; Navas-Carretero, S.; Marsaux, C.F.M.; O’Donovan, C.B.; Kolossa, S.; Moschonis, G.; Walsh, M.C.; Gibney, E.R.; Brennan, L.; Bouwman, J.; Manios, Y.; Jarosz, M.; Martinez, J.A.; Daniel, H.; Saris, W.H.M.; Gundersen, T.E.; Drevon, C.A.; Gibney, M.J.; Mathers, J.C.; Lovegrove, J.A.

2018-01-01

Diet-quality scores (DQS), which are developed across the globe, are used to define adherence to specific eating patterns and have been associated with risk of coronary heart disease and type-II diabetes. We explored the association between five diet-quality scores (Healthy Eating Index, HEI;

A new multimodal interactive way of subjective scoring of 3D video quality of experience

Science.gov (United States)

Kim, Taewan; Lee, Kwanghyun; Lee, Sanghoon; Bovik, Alan C.

2014-03-01

People that watch today's 3D visual programs, such as 3D cinema, 3D TV and 3D games, experience wide and dynamically varying ranges of 3D visual immersion and 3D quality of experience (QoE). It is necessary to be able to deploy reliable methodologies that measure each viewers subjective experience. We propose a new methodology that we call Multimodal Interactive Continuous Scoring of Quality (MICSQ). MICSQ is composed of a device interaction process between the 3D display and a separate device (PC, tablet, etc.) used as an assessment tool, and a human interaction process between the subject(s) and the device. The scoring process is multimodal, using aural and tactile cues to help engage and focus the subject(s) on their tasks. Moreover, the wireless device interaction process makes it possible for multiple subjects to assess 3D QoE simultaneously in a large space such as a movie theater, and at di®erent visual angles and distances.

A Force Balanced Fragmentation Method for ab Initio Molecular Dynamic Simulation of Protein

Directory of Open Access Journals (Sweden)

Mingyuan Xu

2018-05-01

Full Text Available A force balanced generalized molecular fractionation with conjugate caps (FB-GMFCC method is proposed for ab initio molecular dynamic simulation of proteins. In this approach, the energy of the protein is computed by a linear combination of the QM energies of individual residues and molecular fragments that account for the two-body interaction of hydrogen bond between backbone peptides. The atomic forces on the caped H atoms were corrected to conserve the total force of the protein. Using this approach, ab initio molecular dynamic simulation of an Ace-(ALA9-NME linear peptide showed the conservation of the total energy of the system throughout the simulation. Further a more robust 110 ps ab initio molecular dynamic simulation was performed for a protein with 56 residues and 862 atoms in explicit water. Compared with the classical force field, the ab initio molecular dynamic simulations gave better description of the geometry of peptide bonds. Although further development is still needed, the current approach is highly efficient, trivially parallel, and can be applied to ab initio molecular dynamic simulation study of large proteins.

Free Dietary Choice and Free-Range Rearing Improve the Product Quality, Gait Score, and Microbial Richness of Chickens

Directory of Open Access Journals (Sweden)

Siyu Chen

2018-06-01

Full Text Available Poultry welfare has been extensively studied; however, there is a lack of rigorous scientific knowledge relating to the different aspects of welfare factors and how this may contribute to the production quantity and product quality as well as the welfare of chickens. Therefore, we conducted an integrated study to compare welfare factors in chickens by providing free dietary choice under cage rearing, and further comparing cage rearing with free-range rearing. One hundred chickens each were allocated to a cage rearing group with conventional feeding (CC, a cage rearing group with free dietary choice of mealworms (FDM, a cage rearing group with free dietary choice of mealworms and fresh grass (FDMG, and a free-range rearing system group with free dietary choice of mealworms and fresh grass (FRMG. Results showed that under cage rearing, free dietary choice contributed to better meat quality and gait score, higher values of blood platelets, and a richer gut microbial composition, but poorer egg production than CC chickens. As compared to FDMG, FRMG chickens showed better meat quality, gait score, and feather conditions, as well as a richer gut microbial composition; however, they had poorer egg production and a poorer foot pad and foot feather condition. We conclude that free dietary choice and free-range rearing systems improve the product quality, gait score, and microbial richness of chickens.

Diet Quality Scores and Prediction of All-Cause, Cardiovascular and Cancer Mortality in a Pan-European Cohort Study.

Directory of Open Access Journals (Sweden)

Camille Lassale

Full Text Available Scores of overall diet quality have received increasing attention in relation to disease aetiology; however, their value in risk prediction has been little examined. The objective was to assess and compare the association and predictive performance of 10 diet quality scores on 10-year risk of all-cause, CVD and cancer mortality in 451,256 healthy participants to the European Prospective Investigation into Cancer and Nutrition, followed-up for a median of 12.8y. All dietary scores studied showed significant inverse associations with all outcomes. The range of HRs (95% CI in the top vs. lowest quartile of dietary scores in a composite model including non-invasive factors (age, sex, smoking, body mass index, education, physical activity and study centre was 0.75 (0.72-0.79 to 0.88 (0.84-0.92 for all-cause, 0.76 (0.69-0.83 to 0.84 (0.76-0.92 for CVD and 0.78 (0.73-0.83 to 0.91 (0.85-0.97 for cancer mortality. Models with dietary scores alone showed low discrimination, but composite models also including age, sex and other non-invasive factors showed good discrimination and calibration, which varied little between different diet scores examined. Mean C-statistic of full models was 0.73, 0.80 and 0.71 for all-cause, CVD and cancer mortality. Dietary scores have poor predictive performance for 10-year mortality risk when used in isolation but display good predictive ability in combination with other non-invasive common risk factors.

Hong Kong men with low incomes have worse health-related quality of life as judged by SF-36 scores.

Science.gov (United States)

Ko, G T C; Wai, H P S; Tsang, P C C; Chan, H C K

2006-10-01

To analyse the association between income and health-related quality of life using the Medical Outcome Study Short Form 36 (SF-36) Chinese version in Hong Kong Chinese working population. Cross-sectional observation study. A commercial company in Hong Kong. All clerical and administrative staff of a commercial company was invited to participate; 876 of the 1003 staff agreed. The subjects were categorised into three income groups according to monthly income in Hong Kong dollars (low, 10,000-25,000; high, >25,000). The mean age of the 288 men and 588 women was 34.9 (standard deviation, 7.9; median, 34.0; range, 18-71) years. SF-36 scores on health-related quality of life. The distribution of income was 30% in high-, 54.8% in middle-, and 15.2% in low-income groups. Women had similar SF-36 scores among different income groups. In men, for most variables there was a significant positive linear correlation between income and SF-36 scores. Low income is associated with a worse health-related quality of life in Hong Kong Chinese men.

Many-body optimization using an ab initio monte carlo method.

Science.gov (United States)

Haubein, Ned C; McMillan, Scott A; Broadbelt, Linda J

2003-01-01

Advances in computing power have made it possible to study solvated molecules using ab initio quantum chemistry. Inclusion of discrete solvent molecules is required to determine geometric information about solute/solvent clusters. Monte Carlo methods are well suited to finding minima in many-body systems, and ab initio methods are applicable to the widest range of systems. A first principles Monte Carlo (FPMC) method was developed to find minima in many-body systems, and emphasis was placed on implementing moves that increase the likelihood of finding minimum energy structures. Partial optimization and molecular interchange moves aid in finding minima and overcome the incomplete sampling that is unavoidable when using ab initio methods. FPMC was validated by studying the boron trifluoride-water system, and then the method was used to examine the methyl carbenium ion in water to demonstrate its application to solvation problems.

A comparison of the nutritional quality of organic and conventional ready-to-eat breakfast cereals based on NuVal scores.

Science.gov (United States)

Woodbury, Nancy J; George, Valerie A

2014-07-01

To identify whether there were differences in nutritional quality between organic and conventional ready-to-eat breakfast cereals of similar types, based on NuVal scores. The current descriptive study analysed NuVal scores for 829 ready-to-eat breakfast cereals and eighteen different cereal types. ANOVA was used to compare the mean NuVal scores of 723 conventional cereals with those of 106 organic cereals. Ready-to-eat breakfast cereals (n 829) with NuVal scores. Not applicable. There was no significant difference in NuVal scores between conventional (mean 28·4 (sd 13·4)) and organic (mean 30·6 (sd 13·2)) cereal types. Consumers who choose the organic version of a ready-to-eat breakfast cereal believing that nutritional quality is superior may not be making a valid assumption. Public health nutrition educators must help consumers understand that organic cereals are not necessarily more nutritious and their consumption could result in excessive intake of undesirable nutrients, such as fat, sugar and sodium.

Influence of the ab initio n–d cross sections in the critical heavy-water benchmarks

International Nuclear Information System (INIS)

Morillon, B.; Lazauskas, R.; Carbonell, J.

2013-01-01

Highlights: ► We solve the three nucleon problem using different NN potential (MT, AV18 and INOY) to calculate the Neutron–deuteron cross sections. ► These cross sections are compared to the existing experimental data and to international libraries. ► We describe the different sets of heavy water benchmarks for which the Monte Carlo simulations have been performed including our new Neutron–deuteron cross sections. ► The results obtained by the ab initio INOY potential have been compared with the calculations based on the international library cross sections and are found to be of the same quality. - Abstract: The n–d elastic and breakup cross sections are computed by solving the three-body Faddeev equations for realistic and semi-realistic nucleon–nucleon potentials. These cross sections are inserted in the Monte Carlo simulation of the nuclear processes considered in the International Handbook of Evaluated Criticality Safety Benchmark Experiments (ICSBEP Handbook). The results obtained using thes ab initio n–d cross sections are compared with those provided by the most renown international libraries

Towards hydrogen metallization: an Ab initio approach

International Nuclear Information System (INIS)

Bernard, St.

1998-01-01

The quest for metallic hydrogen is a major goal for both theoretical and experimental condensed matter physics. Hydrogen and deuterium have been compressed up to 200 GPa in diamond anvil cells, without any clear evidence for a metallic behaviour. Loubeyere has recently suggested that hydrogen could metallize, at pressures within experimental range, in a new Van der Waals compound: Ar(H 2 ) 2 which is characterized at ambient pressure by an open and anisotropic sublattice of hydrogen molecules, stabilized by an argon skeleton. This thesis deals with a detailed ab initio investigation, by Car-Parrinello molecular dynamics methods, of the evolution under pressure of this compound. In a last chapter, we go to much higher pressures and temperatures, in order to compare orbital and orbital free ab initio methods for the dense hydrogen plasma. (author)

Perspective: Ab initio force field methods derived from quantum mechanics

Science.gov (United States)

Xu, Peng; Guidez, Emilie B.; Bertoni, Colleen; Gordon, Mark S.

2018-03-01

It is often desirable to accurately and efficiently model the behavior of large molecular systems in the condensed phase (thousands to tens of thousands of atoms) over long time scales (from nanoseconds to milliseconds). In these cases, ab initio methods are difficult due to the increasing computational cost with the number of electrons. A more computationally attractive alternative is to perform the simulations at the atomic level using a parameterized function to model the electronic energy. Many empirical force fields have been developed for this purpose. However, the functions that are used to model interatomic and intermolecular interactions contain many fitted parameters obtained from selected model systems, and such classical force fields cannot properly simulate important electronic effects. Furthermore, while such force fields are computationally affordable, they are not reliable when applied to systems that differ significantly from those used in their parameterization. They also cannot provide the information necessary to analyze the interactions that occur in the system, making the systematic improvement of the functional forms that are used difficult. Ab initio force field methods aim to combine the merits of both types of methods. The ideal ab initio force fields are built on first principles and require no fitted parameters. Ab initio force field methods surveyed in this perspective are based on fragmentation approaches and intermolecular perturbation theory. This perspective summarizes their theoretical foundation, key components in their formulation, and discusses key aspects of these methods such as accuracy and formal computational cost. The ab initio force fields considered here were developed for different targets, and this perspective also aims to provide a balanced presentation of their strengths and shortcomings. Finally, this perspective suggests some future directions for this actively developing area.

Single-ion 4f element magnetism: an ab-initio look at Ln(COT)2(-).

Science.gov (United States)

Gendron, Frédéric; Pritchard, Benjamin; Bolvin, Hélène; Autschbach, Jochen

2015-12-14

The electron densities associated with the Ln 4f shell, and spin and orbital magnetizations ('magnetic moment densities'), are investigated for the Ln(COT)2(-) series. The densities are obtained from ab-initio calculations including spin-orbit coupling. For Ln = Ce, Pr the magnetizations are also derived from crystal field models and shown to agree with the ab-initio results. Analysis of magnetizations from ab-initio calculations may be useful in assisting research on single molecule magnets.

The Quality of Toddler Child Care and Cognitive Skills at 24 Months: Propensity Score Analysis Results from the ECLS-B

Science.gov (United States)

Ruzek, Erik; Burchinal, Margaret; Farkas, George; Duncan, Greg J.

2013-01-01

Over half of the toddlers in the U.S. experience routine nonparental care, but much less is known about early care than about preschool care. This study analyzed 2-year-old child care and child outcome data from the nationally representative ECLS-B sample of children born in 2001. At two-years of age, 51% of children experienced exclusive parental care, 18% relative care, 15% family child care, and 16% center care. More children in nonparental care were in medium quality care (61%) than in high quality (26%) or low quality (13%) care. Low-income children were more likely than non-low income children to be cared for by their parents and, when in care, were more often in lower quality care. The impact of toddler care quality on cognitive skills was estimated using propensity score adjustments to account for potential selection confounds due to family and child characteristics. Children’s cognitive scores were higher in high or medium quality care than in low quality care, but no evidence emerged suggesting that poverty moderated the quality effects. Nevertheless, this suggests that increasing the proportion of low-income children in high quality care could reduce the achievement gap because low-income children are very unlikely to experience high quality care. PMID:24347815

Ab initio calculations of 3H(d,n)4He fusion

International Nuclear Information System (INIS)

Navratil, Petr; Quaglioni, Sofia

2012-01-01

We build a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the ab initio no-core shell model. In this way, we complement a microscopic-cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. We will present the first results of the d- 3 H and d- 3 He fusion calculation obtained within our ab initio approach. We will also discuss our d- 4 He, 3 H- 4 He and 3 H- 3 H scattering calculations and the outline of the extension of the formalism to include three-cluster final states with the goal to calculate the 3 H( 3 H,2n) 4 He cross section

SF-36 total score as a single measure of health-related quality of life: Scoping review.

Science.gov (United States)

Lins, Liliane; Carvalho, Fernando Martins

2016-01-01

According to the 36-Item Short Form Health Survey questionnaire developers, a global measure of health-related quality of life such as the "SF-36 Total/Global/Overall Score" cannot be generated from the questionnaire. However, studies keep on reporting such measure. This study aimed to evaluate the frequency and to describe some characteristics of articles reporting the SF-36 Total/Global/Overall Score in the scientific literature. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses method was adapted to a scoping review. We performed searches in PubMed, Web of Science, SCOPUS, BVS, and Cochrane Library databases for articles using such scores. We found 172 articles published between 1997 and 2015; 110 (64.0%) of them were published from 2010 onwards; 30.0% appeared in journals with Impact Factor 3.00 or greater. Overall, 129 (75.0%) out of the 172 studies did not specify the method for calculating the "SF-36 Total Score"; 13 studies did not specify their methods but referred to the SF-36 developers' studies or others; and 30 articles used different strategies for calculating such score, the most frequent being arithmetic averaging of the eight SF-36 domains scores. We concluded that the "SF-36 Total/Global/Overall Score" has been increasingly reported in the scientific literature. Researchers should be aware of this procedure and of its possible impacts upon human health.

Ab Initio Nuclear Structure and Reaction Calculations for Rare Isotopes

Energy Technology Data Exchange (ETDEWEB)

Draayer, Jerry P. [Louisiana State Univ., Baton Rouge, LA (United States)

2014-09-28

We have developed a novel ab initio symmetry-adapted no-core shell model (SA-NCSM), which has opened the intermediate-mass region for ab initio investigations, thereby providing an opportunity for first-principle symmetry-guided applications to nuclear structure and reactions for nuclear isotopes from the lightest p-shell systems to intermediate-mass nuclei. This includes short-lived proton-rich nuclei on the path of X-ray burst nucleosynthesis and rare neutron-rich isotopes to be produced by the Facility for Rare Isotope Beams (FRIB). We have provided ab initio descriptions of high accuracy for low-lying (including collectivity-driven) states of isotopes of Li, He, Be, C, O, Ne, Mg, Al, and Si, and studied related strong- and weak-interaction driven reactions that are important, in astrophysics, for further understanding stellar evolution, X-ray bursts and triggering of s, p, and rp processes, and in applied physics, for electron and neutrino-nucleus scattering experiments as well as for fusion ignition at the National Ignition Facility (NIF).

Ab Initio Nuclear Structure and Reaction Calculations for Rare Isotopes

International Nuclear Information System (INIS)

Draayer, Jerry P.

2014-01-01

We have developed a novel ab initio symmetry-adapted no-core shell model (SA-NCSM), which has opened the intermediate-mass region for ab initio investigations, thereby providing an opportunity for first-principle symmetry-guided applications to nuclear structure and reactions for nuclear isotopes from the lightest p-shell systems to intermediate-mass nuclei. This includes short-lived proton-rich nuclei on the path of X-ray burst nucleosynthesis and rare neutron-rich isotopes to be produced by the Facility for Rare Isotope Beams (FRIB). We have provided ab initio descriptions of high accuracy for low-lying (including collectivity-driven) states of isotopes of Li, He, Be, C, O, Ne, Mg, Al, and Si, and studied related strong- and weak-interaction driven reactions that are important, in astrophysics, for further understanding stellar evolution, X-ray bursts and triggering of s, p, and rp processes, and in applied physics, for electron and neutrino-nucleus scattering experiments as well as for fusion ignition at the National Ignition Facility (NIF).

Predicting performance and injury resilience from movement quality and fitness scores in a basketball team over 2 years.

Science.gov (United States)

McGill, Stuart M; Andersen, Jordan T; Horne, Arthur D

2012-07-01

The purpose of this study was to see if specific tests of fitness and movement quality could predict injury resilience and performance in a team of basketball players over 2 years (2 playing seasons). It was hypothesized that, in a basketball population, movement and fitness scores would predict performance scores and that movement and fitness scores would predict injury resilience. A basketball team from a major American university (N = 14) served as the test population in this longitudinal trial. Variables linked to fitness, movement ability, speed, strength, and agility were measured together with some National Basketball Association (NBA) combine tests. Dependent variables of performance indicators (such as games and minutes played, points scored, assists, rebounds, steal, and blocks) and injury reports were tracked for the subsequent 2 years. Results showed that better performance was linked with having a stiffer torso, more mobile hips, weaker left grip strength, and a longer standing long jump, to name a few. Of the 3 NBA combine tests administered here, only a faster lane agility time had significant links with performance. Some movement qualities and torso endurance were not linked. No patterns with injury emerged. These observations have implications for preseason testing and subsequent training programs in an attempt to reduce future injury and enhance playing performance.

An ab initio and TD DFT

Indian Academy of Sciences (India)

The photophysical behaviour of N-(2-hydroxy benzylidene) aniline or most commonly known as salicylideneaniline (SA) has been investigated using the ab initio and DFT levels of theory. The quantum chemical calculations show that the optimized non planar enol (1) form of the SA molecule is the most stable conformer ...

D-score: a search engine independent MD-score.

Science.gov (United States)

Vaudel, Marc; Breiter, Daniela; Beck, Florian; Rahnenführer, Jörg; Martens, Lennart; Zahedi, René P

2013-03-01

While peptides carrying PTMs are routinely identified in gel-free MS, the localization of the PTMs onto the peptide sequences remains challenging. Search engine scores of secondary peptide matches have been used in different approaches in order to infer the quality of site inference, by penalizing the localization whenever the search engine similarly scored two candidate peptides with different site assignments. In the present work, we show how the estimation of posterior error probabilities for peptide candidates allows the estimation of a PTM score called the D-score, for multiple search engine studies. We demonstrate the applicability of this score to three popular search engines: Mascot, OMSSA, and X!Tandem, and evaluate its performance using an already published high resolution data set of synthetic phosphopeptides. For those peptides with phosphorylation site inference uncertainty, the number of spectrum matches with correctly localized phosphorylation increased by up to 25.7% when compared to using Mascot alone, although the actual increase depended on the fragmentation method used. Since this method relies only on search engine scores, it can be readily applied to the scoring of the localization of virtually any modification at no additional experimental or in silico cost. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Scoring Mental Health Quality of Life With the SF-36 in Patients With and Without Diabetes Foot Complications.

Science.gov (United States)

Ahn, Junho; Del Core, Michael A; Wukich, Dane K; Liu, George T; Lalli, Trapper; VanPelt, Michael D; La Fontaine, Javier; Lavery, Lawrence A; Raspovic, Katherine M

2018-03-01

The aim of this study was to examine if using orthogonal and oblique factor analysis detect changes in health-related quality of life differently in diabetic patients on the Short Form-36 (SF-36) survey. A total of 155 patients had diabetic foot complications (DFC), and 145 patients had no DFCs. The SF-36 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores were calculated using scoring coefficients determined by orthogonal and oblique rotation principle component analyses of the subscales. The DFC group had lower orthogonal ( P < .00001) and oblique PCS scores ( P < .00001). However, despite lower Mental Health subscale scores in the patients with DFCs, orthogonal MCS scores ( P = .156) did not differ. In contrast, the oblique MCS scores reflected the difference in the Mental Health subscale ( P = .0005). Orthogonal and oblique PCS scores did not differ significantly. However, orthogonal MCS scores were significantly higher than oblique MCS scores in those with DFCs ( P = .0004) and without DFCs ( P = .005). The shorter, 12-item SF-12 survey demonstrated similar results. Poorer physical function leads to higher orthogonal MCS scores than if determined by oblique scoring coefficients since Physical Function, Bodily Pain, and General Health are weighted more negatively in orthogonal coefficients when calculating the MCS score. Oblique scoring coefficients may address this issue, but further study is necessary to confirm whether oblique MCS scores accurately represent the mental health of patients with diabetic foot disease.

Quantifying radioxerostomia: salivary flow rate, examiner's score, and quality of life questionnaire

Energy Technology Data Exchange (ETDEWEB)

Al-Nawas, B.; Al-Nawas, K.; Kunkel, M.; Groetz, K.A. [Dept. of Oral and Maxillofacial Surgery, Hospital of the Johannes Gutenberg Univ., Mainz (Germany)

2006-06-15

Background and purpose: salivary flow rates alone are not sufficient to quantify all aspects of radioxerostomia. This is a problem in studies aiming to reduce radioxerostomia. The aim of this study was to evaluate the association between objectively measured salivary flow rate and subjective xerostomia ratings by the physician (RTOG scale) or the patients (quality of life [QoL] questionnaire). Patients and methods: in a case-control study patients who underwent recall for oral cancer were screened. Inclusion criteria for this diagnostic, noninterventional study were: history of oral carcinoma, surgical and radiation therapy, time interval from start of radiation therapy > 90 days, salivary glands within the radiation field. The control group consisted of patients, who had not received radiotherapy. RTOG salivary gland score, quality of life (EORTC QLQ-C30 and H and N35), and sialometry were recorded. Results: patients with RTOG score 0 had mean salivary flow rates of 0.3 ml/min, those with RTOG 1 0.12 ml/min, RTOG 2 0.02 ml/min, and RTOG 3 < 0.01 ml/min. RTOG score 4 (total fibrosis) did not occur. Based on salivary flow rates, all patients were grouped into xerostomia < 0.2 ml/min (30 patients) and nonxerostomia (twelve patients). QoL results revealed significant differences between patients with xerostomia and nonxerostomia for physical function, dyspnea, swallowing, social eating, dry mouth, nutritional support, and a tendency to higher values for appetite loss. Conclusion: the correlation between ''subjective'' QoL parameters and salivary flow was confirmed. The different subjective aspects of radioxerostomia seem to be better differentiated by the EORTC QoL questionnaire. (orig.)

Ab-initio calculations of superconducting properties of YBa2Cu3O7

International Nuclear Information System (INIS)

Zhao, G.L.; Bagayoko, D.

1999-01-01

The authors present ab-initio calculations for the electronic structure and superconducting properties of YBa 2 Cu 3 O 7 (YBCO). The electronic structure was calculated using a self-consistent ab-initio LCAO method. They solved the anisotropic Eliashberg gap equation numerically. The strong coupling of the high energy optical phonons around 60--73 meV, with the electrons at the Fermi surface, leads to a high Tc in YBCO. The calculated Tc is about 89 K for μ* = 0.1. The good agreement of the calculated results with experimental measurements and the ab-initio nature of the calculations support the scenario of an anisotropic s-wave superconductor for YBCO

Use of ab initio quantum chemical methods in battery technology

Energy Technology Data Exchange (ETDEWEB)

Deiss, E [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

Ab initio quantum chemistry can nowadays predict physical and chemical properties of molecules and solids. An attempt should be made to use this tool more widely for predicting technologically favourable materials. To demonstrate the use of ab initio quantum chemistry in battery technology, the theoretical energy density (energy per volume of active electrode material) and specific energy (energy per mass of active electrode material) of a rechargeable lithium-ion battery consisting of a graphite electrode and a nickel oxide electrode has been calculated with this method. (author) 1 fig., 1 tab., 7 refs.

Ab Initio molecular dynamics with excited electrons

NARCIS (Netherlands)

Alavi, A.; Kohanoff, J.; Parrinello, M.; Frenkel, D.

1994-01-01

A method to do ab initio molecular dynamics suitable for metallic and electronically hot systems is described. It is based on a density functional which is costationary with the finite-temperature functional of Mermin, with state being included with possibly fractional occupation numbers.

Ab Initio Calculations Of Light-Ion Reactions

International Nuclear Information System (INIS)

Navratil, P.; Quaglioni, S.; Roth, R.; Horiuchi, W.

2012-01-01

The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. In addition to the complex nature of nuclear forces, one faces the quantum-mechanical many-nucleon problem governed by an interplay between bound and continuum states. In recent years, significant progress has been made in ab initio nuclear structure and reaction calculations based on input from QCD employing Hamiltonians constructed within chiral effective field theory. In this contribution, we present one of such promising techniques capable of describing simultaneously both bound and scattering states in light nuclei. By combining the resonating-group method (RGM) with the ab initio no-core shell model (NCSM), we complement a microscopic cluster approach with the use of realistic interactions and a microscopic and consistent description of the clusters. We discuss applications to light nuclei scattering, radiative capture and fusion reactions.

Introducing ab initio based neural networks for transition-rate prediction in kinetic Monte Carlo simulations

Science.gov (United States)

Messina, Luca; Castin, Nicolas; Domain, Christophe; Olsson, Pär

2017-02-01

The quality of kinetic Monte Carlo (KMC) simulations of microstructure evolution in alloys relies on the parametrization of point-defect migration rates, which are complex functions of the local chemical composition and can be calculated accurately with ab initio methods. However, constructing reliable models that ensure the best possible transfer of physical information from ab initio to KMC is a challenging task. This work presents an innovative approach, where the transition rates are predicted by artificial neural networks trained on a database of 2000 migration barriers, obtained with density functional theory (DFT) in place of interatomic potentials. The method is tested on copper precipitation in thermally aged iron alloys, by means of a hybrid atomistic-object KMC model. For the object part of the model, the stability and mobility properties of copper-vacancy clusters are analyzed by means of independent atomistic KMC simulations, driven by the same neural networks. The cluster diffusion coefficients and mean free paths are found to increase with size, confirming the dominant role of coarsening of medium- and large-sized clusters in the precipitation kinetics. The evolution under thermal aging is in better agreement with experiments with respect to a previous interatomic-potential model, especially concerning the experiment time scales. However, the model underestimates the solubility of copper in iron due to the excessively high solution energy predicted by the chosen DFT method. Nevertheless, this work proves the capability of neural networks to transfer complex ab initio physical properties to higher-scale models, and facilitates the extension to systems with increasing chemical complexity, setting the ground for reliable microstructure evolution simulations in a wide range of alloys and applications.

Ab initio nuclear structure - the large sparse matrix eigenvalue problem

Energy Technology Data Exchange (ETDEWEB)

Vary, James P; Maris, Pieter [Department of Physics, Iowa State University, Ames, IA, 50011 (United States); Ng, Esmond; Yang, Chao [Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Sosonkina, Masha, E-mail: jvary@iastate.ed [Scalable Computing Laboratory, Ames Laboratory, Iowa State University, Ames, IA, 50011 (United States)

2009-07-01

The structure and reactions of light nuclei represent fundamental and formidable challenges for microscopic theory based on realistic strong interaction potentials. Several ab initio methods have now emerged that provide nearly exact solutions for some nuclear properties. The ab initio no core shell model (NCSM) and the no core full configuration (NCFC) method, frame this quantum many-particle problem as a large sparse matrix eigenvalue problem where one evaluates the Hamiltonian matrix in a basis space consisting of many-fermion Slater determinants and then solves for a set of the lowest eigenvalues and their associated eigenvectors. The resulting eigenvectors are employed to evaluate a set of experimental quantities to test the underlying potential. For fundamental problems of interest, the matrix dimension often exceeds 10{sup 10} and the number of nonzero matrix elements may saturate available storage on present-day leadership class facilities. We survey recent results and advances in solving this large sparse matrix eigenvalue problem. We also outline the challenges that lie ahead for achieving further breakthroughs in fundamental nuclear theory using these ab initio approaches.

Ab initio nuclear structure - the large sparse matrix eigenvalue problem

International Nuclear Information System (INIS)

Vary, James P; Maris, Pieter; Ng, Esmond; Yang, Chao; Sosonkina, Masha

2009-01-01

The structure and reactions of light nuclei represent fundamental and formidable challenges for microscopic theory based on realistic strong interaction potentials. Several ab initio methods have now emerged that provide nearly exact solutions for some nuclear properties. The ab initio no core shell model (NCSM) and the no core full configuration (NCFC) method, frame this quantum many-particle problem as a large sparse matrix eigenvalue problem where one evaluates the Hamiltonian matrix in a basis space consisting of many-fermion Slater determinants and then solves for a set of the lowest eigenvalues and their associated eigenvectors. The resulting eigenvectors are employed to evaluate a set of experimental quantities to test the underlying potential. For fundamental problems of interest, the matrix dimension often exceeds 10 10 and the number of nonzero matrix elements may saturate available storage on present-day leadership class facilities. We survey recent results and advances in solving this large sparse matrix eigenvalue problem. We also outline the challenges that lie ahead for achieving further breakthroughs in fundamental nuclear theory using these ab initio approaches.

State-of-the-art ab initio potential energy curve for the xenon atom pair and related spectroscopic and thermophysical properties

Science.gov (United States)

Hellmann, Robert; Jäger, Benjamin; Bich, Eckard

2017-07-01

A new ab initio interatomic potential energy curve for two ground-state xenon atoms is presented. It is based on supermolecular calculations at the coupled-cluster level with single, double, and perturbative triple excitations [CCSD(T)] employing basis sets up to sextuple-zeta quality, which were developed as part of this work. In addition, corrections were determined for higher coupled-cluster levels up to CCSDTQ as well as for scalar and spin-orbit relativistic effects at the CCSD(T) level. A physically motivated analytical function was fitted to the calculated interaction energies and used to compute the vibrational spectrum of the dimer, the second virial coefficient, and the dilute gas transport properties. The agreement with the best available experimental data for the investigated properties is excellent; the new potential function is superior not only to previous ab initio potentials but also to the most popular empirical ones.

State-of-the-art ab initio potential energy curve for the xenon atom pair and related spectroscopic and thermophysical properties.

Science.gov (United States)

Hellmann, Robert; Jäger, Benjamin; Bich, Eckard

2017-07-21

A new ab initio interatomic potential energy curve for two ground-state xenon atoms is presented. It is based on supermolecular calculations at the coupled-cluster level with single, double, and perturbative triple excitations [CCSD(T)] employing basis sets up to sextuple-zeta quality, which were developed as part of this work. In addition, corrections were determined for higher coupled-cluster levels up to CCSDTQ as well as for scalar and spin-orbit relativistic effects at the CCSD(T) level. A physically motivated analytical function was fitted to the calculated interaction energies and used to compute the vibrational spectrum of the dimer, the second virial coefficient, and the dilute gas transport properties. The agreement with the best available experimental data for the investigated properties is excellent; the new potential function is superior not only to previous ab initio potentials but also to the most popular empirical ones.

Bowel Endometriosis Syndrome: a new scoring system for pelvic organ dysfunction and quality of life.

Science.gov (United States)

Riiskjær, M; Egekvist, A G; Hartwell, D; Forman, A; Seyer-Hansen, M; Kesmodel, U S

2017-09-01

Is it possible to develop a validated score that can identify women with Bowel Endometriosis Syndrome (BENS) and be used to monitor the effect of medical and surgical treatment? The BENS score can be used to identify women with BENS and to monitor the effect of medical and surgical treatment of women suffering from bowel endometriosis. Endometriosis is a heterogeneous disease with extensive variation in anatomical and clinical presentation, and symptoms do not always correspond to the disease burden. Current endometriosis scoring systems are mainly based on anatomical and surgical findings. The score was developed and validated from a cohort of 525 women with medically or surgically treated bowel endometriosis from Aarhus and Copenhagen University Hospitals, Denmark. Patients filled in questionnaires on pelvic pain, quality of life (QoL) and urinary, sexual and bowel function. Items were selected for the final score using clinical and statistical criteria. The chosen variables were included in a multivariate analysis. Individual score values were designated items to form the BENS score, which was divided into 'no BENS', 'minor BENS' and 'major BENS.' Internal and external validations were performed. The six most important items were 'pelvic pain', 'use of analgesics', 'dyschezia', 'straining to urinate', 'fecal urgency' and 'satisfaction with sexual life'. The range of the BENS score (0-28) was divided into 0-8 (no BENS), 9-16 (minor BENS) and 17-28 (major BENS). External validation showed a significant association between BENS score and QoL (P = 0.0001). The BENS scoring system is limited by the fact that it was developed from a single endometriosis unit in Denmark, making it susceptible to social, cultural and demographic bias. It is the first endometriosis classification system to be based directly on the symptomatology of the patient. Validation in other languages will promote comparison of treatments and results across borders. No external funding was either

The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study

International Nuclear Information System (INIS)

Perron, A.; Turchi, P.E.A.; Landa, A.; Söderlind, P.; Ravat, B.; Oudot, B.; Delaunay, F.

2015-01-01

Highlights: • The ab initio informed CALPHAD assessment of the Am–U system has been realized. • A strong tendency toward phase separation across the whole composition range is predicted. • The ab initio informed Pu–U–Am thermodynamic database has been developed. • The solubility of Am and U in the liquid phase is improved by adding Pu. • The δ-Pu (fcc) phase is strongly stabilized by Am, on the contrary to the bcc phase. - Abstract: Phase diagram and thermodynamic properties of the Am–U system, that are experimentally unknown, are calculated using the CALPHAD method with input from ab initio electronic-structure calculations for the fcc and bcc phases. A strong tendency toward phase separation across the whole composition range is predicted. In addition, ab initio informed Pu–U and Am–Pu thermodynamic assessments are combined to build a Pu–U–Am thermodynamic database. Regarding the Pu-rich corner of the ternary system, predictions indicate that Am acts as a powerful δ-Pu (fcc) stabilizer. In the U-rich corner, similar predictions are made but to a lesser extent. In both cases, the bcc phase is destabilized and the fcc phase is enhanced. Finally, results and methodology are discussed and compared with previous assessments and guidelines are provided for further experimental studies

The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study

Energy Technology Data Exchange (ETDEWEB)

Perron, A., E-mail: perron1@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Turchi, P.E.A.; Landa, A.; Söderlind, P. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Ravat, B.; Oudot, B.; Delaunay, F. [CEA-Centre de Valduc, 21120 Is sur Tille (France)

2015-03-15

Highlights: • The ab initio informed CALPHAD assessment of the Am–U system has been realized. • A strong tendency toward phase separation across the whole composition range is predicted. • The ab initio informed Pu–U–Am thermodynamic database has been developed. • The solubility of Am and U in the liquid phase is improved by adding Pu. • The δ-Pu (fcc) phase is strongly stabilized by Am, on the contrary to the bcc phase. - Abstract: Phase diagram and thermodynamic properties of the Am–U system, that are experimentally unknown, are calculated using the CALPHAD method with input from ab initio electronic-structure calculations for the fcc and bcc phases. A strong tendency toward phase separation across the whole composition range is predicted. In addition, ab initio informed Pu–U and Am–Pu thermodynamic assessments are combined to build a Pu–U–Am thermodynamic database. Regarding the Pu-rich corner of the ternary system, predictions indicate that Am acts as a powerful δ-Pu (fcc) stabilizer. In the U-rich corner, similar predictions are made but to a lesser extent. In both cases, the bcc phase is destabilized and the fcc phase is enhanced. Finally, results and methodology are discussed and compared with previous assessments and guidelines are provided for further experimental studies.

Ab Initio Atomistic Thermodynamics for Surfaces: A Primer

National Research Council Canada - National Science Library

Rogal, Jutta; Reuter, Karsten

2006-01-01

.... These techniques are referred to as first-principles (or in latin: ab initio) to indicate that they do not rely on empirical or fitted parameters, which then makes them applicable for a wide range of realistic conditions...

Negative emotions affect postoperative scores for evaluating functional knee recovery and quality of life after total knee replacement

Directory of Open Access Journals (Sweden)

A. Qi

2016-01-01

Full Text Available This study aimed to determine whether psychological factors affect health-related quality of life (HRQL and recovery of knee function in total knee replacement (TKR patients. A total of 119 TKR patients (male: 38; female: 81 completed the Beck Anxiety Inventory (BAI, Beck Depression Inventory (BDI, State Trait Anxiety Inventory (STAI, Eysenck Personality Questionnaire-revised (EPQR-S, Knee Society Score (KSS, and HRQL (SF-36. At 1 and 6 months after surgery, anxiety, depression, and KSS scores in TKR patients were significantly better compared with those preoperatively (P<0.05. SF-36 scores at the sixth month after surgery were significantly improved compared with preoperative scores (P<0.001. Preoperative Physical Component Summary Scale (PCS and Mental Component Summary Scale (MCS scores were negatively associated with extraversion (E score (B=-0.986 and -0.967, respectively, both P<0.05. Postoperative PCS and State Anxiety Inventory (SAI scores were negatively associated with neuroticism (N score; B=-0.137 and -0.991, respectively, both P<0.05. Postoperative MCS, SAI, Trait Anxiety Inventory (TAI, and BAI scores were also negatively associated with the N score (B=-0.367, -0.107, -0.281, and -0.851, respectively, all P<0.05. The KSS function score at the sixth month after surgery was negatively associated with TAI and N scores (B=-0.315 and -0.532, respectively, both P<0.05, but positively associated with the E score (B=0.215, P<0.05. The postoperative KSS joint score was positively associated with postoperative PCS (B=0.356, P<0.05. In conclusion, for TKR patients, the scores used for evaluating recovery of knee function and HRQL after 6 months are inversely associated with the presence of negative emotions.

Health related quality of life among myocardial infarction survivors in the United States: a propensity score matched analysis.

Science.gov (United States)

Mollon, Lea; Bhattacharjee, Sandipan

2017-12-04

Little is known regarding the health-related quality of life among myocardial infarction (MI) survivors in the United States. The purpose of this population-based study was to identify differences in health-related quality of life domains between MI survivors and propensity score matched controls. This retrospective, cross-sectional matched case-control study examined differences in health-related quality of life (HRQoL) among MI survivors of myocardial infarction compared to propensity score matched controls using data from the 2015 Behavioral Risk Factor Surveillance System (BRFSS) survey. Propensity scores were generated via logistic regression for MI survivors and controls based on gender, race/ethnicity, age, body mass index (BMI), smoking status, and comorbidities. Chi-square tests were used to compare differences between MI survivors to controls for demographic variables. A multivariate analysis of HRQoL domains estimated odds ratios. Life satisfaction, sleep quality, and activity limitations were estimated using binary logistic regression. Social support, perceived general health, perceived physical health, and perceived mental health were estimated using multinomial logistic regression. Significance was set at p 15 days in the month (AOR = 1.63, 95% CI: 1.46-1.83) and poor mental health >15 days in the month (AOR = 1.25, 95% CI: 1.07-1.46) compared to matched controls. There was no difference in survivors compared to controls in level of emotional support (rarely/never: AOR = 0.75, 95% CI: 0.48-1.18; sometimes: AOR = 0.73, 95% CI: 0.41-1.28), hours of recommended sleep (AOR = 1.14, 95% CI: 0.94-1.38), or life satisfaction (AOR = 1.62, 95% CI: 0.99-2.63). MI survivors experienced lower HRQoL on domains of general health, physical health, daily activity, and mental health compared to the general population.

Time-resolved photoelectron spectroscopy and ab initio multiple spawning studies of hexamethylcyclopentadiene

DEFF Research Database (Denmark)

Wolf, T. J. A.; Kuhlman, Thomas Scheby; Schalk, O.

2014-01-01

Time-resolved photoelectron spectroscopy and ab initio multiple spawning were applied to the ultrafast non-adiabatic dynamics of hexamethylcyclopentadiene. The high level of agreement between experiment and theory associates wavepacket motion with a distinct degree of freedom.......Time-resolved photoelectron spectroscopy and ab initio multiple spawning were applied to the ultrafast non-adiabatic dynamics of hexamethylcyclopentadiene. The high level of agreement between experiment and theory associates wavepacket motion with a distinct degree of freedom....

Ab Initio Molecular Dynamics Simulations of Furfural at the Liquid-Solid Interface

OpenAIRE

Sanwu Wang; Hongli Dang; Wenhua Xue; Darwin Shields; Xin Liu; Friederike C. Jentoft; Daniel E. Resasco

2013-01-01

The bonding configuration and the heat of adsorption of a furfural molecule on the Pd(111) surface were determined by ab initio density-functional-theory calculations. The dynamics of pure liquid water, the liquid-solid interface formed by liquid water and the Pd(111) surface, as well as furfural at the water-Pd interface, were investigated by ab initio molecular dynamics simulations at finite temperatures. Calculations and simulations suggest that the bonding configurati...

Supplementary Material for Finding the Stable Structures of N1-xWX with an Ab-initio High-Throughput Approach

Science.gov (United States)

2015-05-08

Supplementary material for “Finding the stable structures of N1−xWX with an ab - initio high-throughput approach” Michael J. Mehl∗ Center for...AND SUBTITLE Supplementary Material for ’Finding the Stable Structures of N1-xWX with an ab - initio High-throughput Approach’ 5a. CONTRACT NUMBER 5b...and J. Hafner, Ab initio molecular dynamics for open-shell transition metals, Phys. Rev. B 48, 13115–13118 (1993). 2 G. Kresse and J. Hafner, Ab initio

Atomic carbon chains as spin-transmitters: An ab initio transport study

DEFF Research Database (Denmark)

Fürst, Joachim Alexander; Brandbyge, Mads; Jauho, Antti-Pekka

2010-01-01

An atomic carbon chain joining two graphene flakes was recently realized in a ground-breaking experiment by Jin et al. (Phys. Rev. Lett., 102 (2009) 205501). We present ab initio results for the electron transport properties of such chains and demonstrate complete spin-polarization of the transmi......An atomic carbon chain joining two graphene flakes was recently realized in a ground-breaking experiment by Jin et al. (Phys. Rev. Lett., 102 (2009) 205501). We present ab initio results for the electron transport properties of such chains and demonstrate complete spin...

Augmented wave ab initio EFG calculations: some methodological warnings

International Nuclear Information System (INIS)

Errico, Leonardo A.; Renteria, Mario; Petrilli, Helena M.

2007-01-01

We discuss some accuracy aspects inherent to ab initio electronic structure calculations in the understanding of nuclear quadrupole interactions. We use the projector augmented wave method to study the electric-field gradient (EFG) at both Sn and O sites in the prototype cases SnO and SnO 2 . The term ab initio is used in the standard context of the also called first principles methods in the framework of the Density Functional Theory. As the main contributions of EFG calculations to problems in condensed matter physics are related to structural characterizations on the atomic scale, we discuss the 'state of the art' on theoretical EFG calculations and make a brief critical review on the subject, calling attention to some fundamental theoretical aspects

Augmented wave ab initio EFG calculations: some methodological warnings

Energy Technology Data Exchange (ETDEWEB)

Errico, Leonardo A. [Departamento de Fisica-IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC67 (1900) La Plata (Argentina); Renteria, Mario [Departamento de Fisica-IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC67 (1900) La Plata (Argentina); Petrilli, Helena M. [Instituto de Fisica-DFMT, Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil)]. E-mail: hmpetril@macbeth.if.usp.br

2007-02-01

We discuss some accuracy aspects inherent to ab initio electronic structure calculations in the understanding of nuclear quadrupole interactions. We use the projector augmented wave method to study the electric-field gradient (EFG) at both Sn and O sites in the prototype cases SnO and SnO{sub 2}. The term ab initio is used in the standard context of the also called first principles methods in the framework of the Density Functional Theory. As the main contributions of EFG calculations to problems in condensed matter physics are related to structural characterizations on the atomic scale, we discuss the 'state of the art' on theoretical EFG calculations and make a brief critical review on the subject, calling attention to some fundamental theoretical aspects.

Designing a Score-Based Method for the Evaluation of the Nutritional Quality of the Gluten-Free Bakery Products and their Gluten-Containing Counterparts.

Science.gov (United States)

Morreale, Federico; Angelino, Donato; Pellegrini, Nicoletta

2018-04-25

Gluten-free (GF) products are consumed both by individuals with celiac disease and by an increasing number of people with no specific medical needs. Although the technological quality of GF products has been recently improved, their nutritional quality is still scarcely addressed. Moreover, the few published studies report conflicting results, mostly because the information from product nutrition facts is the only considered factor. The aim of the present study was to develop a score-based method for the nutritional evaluation of 134 packaged Italian GF bakery products and to compare it with that of 162 matched gluten-containing (GC) food items. The score included the information from the nutrition facts and the presence/absence of some nutritionally relevant components in the ingredients list. Results indicated an overall low nutritional quality of the considered GF bakery products. Additionally, with the sole exception of GF bread substitutes, there was no difference in nutritional quality between GF and equivalent GC bakery products. Future research and development of GF bakery products may take advantage of this scoring method, as it may represent an easy approach to evaluate their nutritional quality. The present findings do not justify the consumption of packaged GF bakery products by people without any specific medical needs.

AB INITIO calculations of magneto-optical effects

Czech Academy of Sciences Publication Activity Database

Kuneš, Jan; Oppeneer, P. M.

2002-01-01

Roč. 2, - (2002), s. 141-146 ISSN 1346-7948 R&D Projects: GA AV ČR IAA1010214 Institutional research plan: CEZ:AV0Z1010914 Keywords : electronic structure * ab initio calculation * polar magneto-optical Kerr effect * transitiom metal * uranium intermetallics * CrO 2 Subject RIV: BM - Solid Matter Physics ; Magnetism

Unraveling the structure of the h-BN/Rh(111) nanomesh with ab initio calculations

International Nuclear Information System (INIS)

Laskowski, R; Blaha, P

2008-01-01

The properties of a single layer of h-BN on top of a Rh(111) surface are discussed in terms of an ab initio generated force field approach as well as by direct ab initio density-functional theory (DFT) calculations. A single-layer model for the h-BN/Rh(111) nanomesh, in contrast to a previously considered (incomplete) double-layer model of h-BN, can explain the experimental data. The main focus of this work is to compare a force field approach described earlier in (Laskowski et al 2007 Phys. Rev. Lett. 98 106802) with direct ab initio calculations. The calculated geometry of the h-BN layer is very similar to the structure predicted by the force field approach. The ab initio calculated density of states projected on N-p x,y of BN corresponding to 'low' and 'high' regions with respect to the Rh surface shows a 1 eV splitting and thus explains the observed σ-band splitting. Moreover, we find good agreement between calculated and experimental scanning tunneling microscope (STM) images of this system

Longitudinal Prediction of Quality-of-Life Scores and Locomotion in Individuals With Traumatic Spinal Cord Injury.

Science.gov (United States)

Hiremath, Shivayogi V; Hogaboom, Nathan S; Roscher, Melissa R; Worobey, Lynn A; Oyster, Michelle L; Boninger, Michael L

2017-12-01

To examine (1) differences in quality-of-life scores for groups based on transitions in locomotion status at 1, 5, and 10 years postdischarge in a sample of people with spinal cord injury (SCI); and (2) whether demographic factors and transitions in locomotion status can predict quality-of-life measures at these time points. Retrospective case study of the National SCI Database. Model SCI Systems Centers. Individuals with SCI (N=10,190) from 21 SCI Model Systems Centers, identified through the National SCI Model Systems Centers database between the years 1985 and 2012. Subjects had FIM (locomotion mode) data at discharge and at least 1 of the following: 1, 5, or 10 years postdischarge. Not applicable. FIM-locomotion mode; Severity of Depression Scale; Satisfaction With Life Scale; and Craig Handicap Assessment and Reporting Technique. Participants who transitioned from ambulation to wheelchair use reported lower participation and life satisfaction, and higher depression levels (P.05) or life satisfaction (P>.05) compared with those who transitioned from wheelchair to ambulation. Demographic factors and locomotion transitions predicted quality-of-life scores at all time points (P<.05). The results of this study indicate that transitioning from ambulation to wheelchair use can negatively impact psychosocial health 10 years after SCI. Clinicians should be aware of this when deciding on ambulation training. Further work to characterize who may be at risk for these transitions is needed. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Ab initio transport across bismuth selenide surface barriers

KAUST Repository

Narayan, Awadhesh; Rungger, Ivan; Droghetti, Andrea; Sanvito, Stefano

2014-01-01

© 2014 American Physical Society. We investigate the effect of potential barriers in the form of step edges on the scattering properties of Bi2Se3(111) topological surface states by means of large-scale ab initio transport simulations. Our results

Dominant Modes in Light Nuclei - Ab Initio View of Emergent Symmetries

International Nuclear Information System (INIS)

Draayer, J P; Dytrych, T; Launey, K D; Dreyfuss, A C; Langr, D

2015-01-01

An innovative symmetry-guided concept is discussed with a focus on emergent symmetry patterns in complex nuclei. In particular, the ab initio symmetry-adapted no-core shell model (SA-NCSM), which capitalizes on exact as well as partial symmetries that underpin the structure of nuclei, provides remarkable insight into how simple symmetry patterns emerge in the many-body nuclear dynamics from first principles. This ab initio view is complemented by a fully microscopic no-core symplectic shell-model framework (NCSpM), which, in turn, informs key features of the primary physics responsible for the emergent phenomena of large deformation and alpha-cluster substructures in studies of the challenging Hoyle state in Carbon-12 and enhanced collectivity in intermediate-mass nuclei. Furthermore, by recognizing that deformed configurations often dominate the low-energy regime, the SA-NCSM provides a strategy for determining the nature of bound states of nuclei in terms of a relatively small subspace of the symmetry-reorganized complete model space, which opens new domains of nuclei for ab initio investigations, namely, the intermediate-mass region, including isotopes of Ne, Mg, and Si

Trends in Classroom Observation Scores

Science.gov (United States)

Casabianca, Jodi M.; Lockwood, J. R.; McCaffrey, Daniel F.

2015-01-01

Observations and ratings of classroom teaching and interactions collected over time are susceptible to trends in both the quality of instruction and rater behavior. These trends have potential implications for inferences about teaching and for study design. We use scores on the Classroom Assessment Scoring System-Secondary (CLASS-S) protocol from…

Ab initio lattice dynamics of metal surfaces

International Nuclear Information System (INIS)

Heid, R.; Bohnen, K.-P.

2003-01-01

Dynamical properties of atoms on surfaces depend sensitively on their bonding environment and thus provide valuable insight into the local geometry and chemical binding at the boundary of a solid. Density-functional theory provides a unified approach to the calculation of structural and dynamical properties from first principles. Its high accuracy and predictive power for lattice dynamical properties of semiconductor surfaces has been demonstrated in a previous article by Fritsch and Schroeder (Phys. Rep. 309 (1999) 209). In this report, we review the state-of-the-art of these ab initio approaches to surface dynamical properties of metal surfaces. We give a brief introduction to the conceptual framework with focus on recent advances in computational procedures for the ab initio linear-response approach, which have been a prerequisite for an efficient treatment of surface dynamics of noble and transition metals. The discussed applications to clean and adsorbate-covered surfaces demonstrate the high accuracy and reliability of this approach in predicting detailed microscopic properties of the phonon dynamics for a wide range of metallic surfaces

[Evaluation of the adjusted amino acid score by digestibility for estimating the protein quality and protein available in food and diets].

Science.gov (United States)

Pak, N; Vera, G; Araya, H

1985-03-01

The purpose of the present study was to evaluate the amino acid score adjusted by digestibility to estimate protein quality and utilizable protein in foods and diets, considering net protein utilization (NPU) as a biological reference method. Ten foods of vegetable origin and ten of animal origin, as well as eight mixtures of foods of vegetable and animal origin were studied. When all the foods were considered, a positive (r = 0.83) and highly significant correlation (p less than 0.001) between NPU and the amino acid score adjusted by digestibility was found. When the foods were separated according to their origin, this correlation was positive only for the foods of vegetable origin (r = 0.93) and statistically significant (p less than 0.001). Also, only in those foods were similar values found between NPU and amino acid score adjusted by digestibility, as well as in utilizable protein estimated considering both methods. Caution is required to interpret protein quality and utilizable protein values of foods of animal origin and mixtures of foods of vegetable and animal origin when the amino acid score method adjusted by digestibility, or NPU, are utilized.

Identification of the optimal donor quality scoring system and measure of early renal function in kidney transplantation.

LENUS (Irish Health Repository)

Moore, Jason

2009-02-27

The early identification of kidney allografts at risk of later dysfunction has implications for clinical practice. Donor quality scoring systems (preoperative) and measures of early allograft function (first week postoperative) have previously shown practical utility. This study aimed to determine the optimal parameter(s) (preoperative and postoperative) with greatest predictive power for the development of subsequent allograft dysfunction.

Ab initio study of alanine polypeptide chain twisting

DEFF Research Database (Denmark)

Solov'yov, Ilia; Yakubovich, Alexander V.; Solov'yov, Andrey V.

2006-01-01

chains. These particular degrees of freedom are essential for the characterization of the proteins folding process. Calculations have been carried out within the ab initio theoretical framework based on the density functional theory and accounting for all the electrons in the system. We have determined...

Ab initio simulation of dislocation cores in metals

International Nuclear Information System (INIS)

Ventelon, L.

2008-01-01

In the framework of the multi scale simulation of metals and alloys plasticity, the aim of this study is to develop a methodology of ab initio dislocations study and to apply it to the [111] screw dislocation in the bc iron. (A.L.B.)

Steel — ab Initio: Quantum Mechanics Guided Design of New Fe-Based Materials

Science.gov (United States)

Prahl, Ulrich; Bleck, Wolfgang; Saeed-Akbari, Alireza

This contribution reports the results of the collaborative research unit SFB 761 "Steel — ab initio", a cooperative project between RWTH Aachen University and the Max-Planck-Institute for Iron Research in Düsseldorf (MPIE) financed by the German Research Foundation (DFG). For the first time, it is exploited how ab initio approaches may lead to a detailed understanding and thus to a specific improvement of material development. The challenge lies in the combination of abstract natural science theories with rather engineering-like established concepts. Aiming at the technological target of the development of a new type of structural materials based on Fe-Mn-C alloys, the combination of ab initio and engineering methods is new, but could be followed quite successfully. Three major topics are treated in this research unit: a) development of a new method for material- and process-development based on ab initio calculations; b) design of a new class of structural materials with extraordinary property combinations; c) acceleration of development time and reduction of experimental efforts and complexity for material- and process-development. In the present work, an overview of the results of the first five years as well as an outlook for the upcoming three-year period is given.

A Review of Solid-Solution Models of High-Entropy Alloys Based on Ab Initio Calculations

Directory of Open Access Journals (Sweden)

Fuyang Tian

2017-11-01

Full Text Available Similar to the importance of XRD in experiments, ab initio calculations, as a powerful tool, have been applied to predict the new potential materials and investigate the intrinsic properties of materials in theory. As a typical solid-solution material, the large degree of uncertainty of high-entropy alloys (HEAs results in the difficulty of ab initio calculations application to HEAs. The present review focuses on the available ab initio based solid-solution models (virtual lattice approximation, coherent potential approximation, special quasirandom structure, similar local atomic environment, maximum-entropy method, and hybrid Monte Carlo/molecular dynamics and their applications and limits in single phase HEAs.

Exploring the ab initio/classical free energy perturbation method: The hydration free energy of water

International Nuclear Information System (INIS)

Sakane, Shinichi; Yezdimer, Eric M.; Liu, Wenbin; Barriocanal, Jose A.; Doren, Douglas J.; Wood, Robert H.

2000-01-01

The ab initio/classical free energy perturbation (ABC-FEP) method proposed previously by Wood et al. [J. Chem. Phys. 110, 1329 (1999)] uses classical simulations to calculate solvation free energies within an empirical potential model, then applies free energy perturbation theory to determine the effect of changing the empirical solute-solvent interactions to corresponding interactions calculated from ab initio methods. This approach allows accurate calculation of solvation free energies using an atomistic description of the solvent and solute, with interactions calculated from first principles. Results can be obtained at a feasible computational cost without making use of approximations such as a continuum solvent or an empirical cavity formation energy. As such, the method can be used far from ambient conditions, where the empirical parameters needed for approximate theories of solvation may not be available. The sources of error in the ABC-FEP method are the approximations in the ab initio method, the finite sample of configurations, and the classical solvent model. This article explores the accuracy of various approximations used in the ABC-FEP method by comparing to the experimentally well-known free energy of hydration of water at two state points (ambient conditions, and 973.15 K and 600 kg/m3). The TIP4P-FQ model [J. Chem. Phys. 101, 6141 (1994)] is found to be a reliable solvent model for use with this method, even at supercritical conditions. Results depend strongly on the ab initio method used: a gradient-corrected density functional theory is not adequate, but a localized MP2 method yields excellent agreement with experiment. Computational costs are reduced by using a cluster approximation, in which ab initio pair interaction energies are calculated between the solute and up to 60 solvent molecules, while multi-body interactions are calculated with only a small cluster (5 to 12 solvent molecules). Sampling errors for the ab initio contribution to

Realization of prediction of materials properties by ab initio ...

Indian Academy of Sciences (India)

Unknown

alization of the results of ab initio molecular dynamics simulation on atom insertion process to C60 and to carbon nanotube ... micro-clusters to estimate absolute highest occupied mo- .... To analyse the observed properties theoretically,.

Association between Diet-Quality Scores, Adiposity, Total Cholesterol and Markers of Nutritional Status in European Adults: Findings from the Food4Me Study

Directory of Open Access Journals (Sweden)

Rosalind Fallaize

2018-01-01

Full Text Available Diet-quality scores (DQS, which are developed across the globe, are used to define adherence to specific eating patterns and have been associated with risk of coronary heart disease and type-II diabetes. We explored the association between five diet-quality scores (Healthy Eating Index, HEI; Alternate Healthy Eating Index, AHEI; MedDietScore, MDS; PREDIMED Mediterranean Diet Score, P-MDS; Dutch Healthy Diet-Index, DHDI and markers of metabolic health (anthropometry, objective physical activity levels (PAL, and dried blood spot total cholesterol (TC, total carotenoids, and omega-3 index in the Food4Me cohort, using regression analysis. Dietary intake was assessed using a validated Food Frequency Questionnaire. Participants (n = 1480 were adults recruited from seven European Union (EU countries. Overall, women had higher HEI and AHEI than men (p < 0.05, and scores varied significantly between countries. For all DQS, higher scores were associated with lower body mass index, lower waist-to-height ratio and waist circumference, and higher total carotenoids and omega-3-index (p trends < 0.05. Higher HEI, AHEI, DHDI, and P-MDS scores were associated with increased daily PAL, moderate and vigorous activity, and reduced sedentary behaviour (p trend < 0.05. We observed no association between DQS and TC. To conclude, higher DQS, which reflect better dietary patterns, were associated with markers of better nutritional status and metabolic health.

The Pariser-Parr-Pople model for trans-polyenes. I. Ab initio and semiempirical study of the bond alternation in trans-butadiene

Science.gov (United States)

Förner, Wolfgang

1992-03-01

Ab initio investigations of the bond alternation in butadiene are presented. The atomic basis sets applied range from minimal to split valence plus polarization quality. With the latter one the Hartree-Fock limit for the bond alternation is reached. Correlation is considered on Møller-Plesset many-body perturbation theory of second order (MP2), linear coupled cluster doubles (L-CCD) and coupled cluster doubles (CCD) level. For the smaller basis sets it is shown that for the bond alternation π-π correlations are essential while the effects of σ-σ and σ-π correlations are, though large, nearly independent of bond alternation. On MP2 level the variation of σ-π correlation with bond alternation is surprisingly large. This is discussed as an artefact of MP2. Comparative Su-Schrieffer-Heeger (SSH) and Pariser-Parr-Pople (PPP) calculations show that these models in their usual parametrizations cannot reproduce the ab initio results.

Ab Initio Calculations and Raman and SERS Spectral Analyses of Amphetamine Species

DEFF Research Database (Denmark)

Berg, Rolf W.; Nørbygaard, Thomas; White, Peter C.

2011-01-01

For the first time, the differences between the spectra of amphetamine and amphetamine-H+ and between different conformers are thoroughly studied by ab initio model calculations, and Raman and surface-enhanced Raman spectroscopy (SERS) spectra are measured for different species of amphetamine....... The spectra of amphetamine and amphetamine-H+ sampleswere obtained and assigned according to a comparison of the experimental spectra and the ab initio MO calculations, performed using the Gaussian 03W program (Gaussian, Inc., Pittsburgh, PA). The analyses were based on complete geometry minimization...

Ab Initio Calculations of Transport in Titanium and Aluminum Mixtures

Science.gov (United States)

Walker, Nicholas; Novak, Brian; Tam, Ka Ming; Moldovan, Dorel; Jarrell, Mark

In classical molecular dynamics simulations, the self-diffusion and shear viscosity of titanium about the melting point have fallen within the ranges provided by experimental data. However, the experimental data is difficult to collect and has been rather scattered, making it of limited value for the validation of these calculations. By using ab initio molecular dynamics simulations within the density functional theory framework, the classical molecular dynamics data can be validated. The dynamical data from the ab initio molecular dynamics can also be used to calculate new potentials for use in classical molecular dynamics, allowing for more accurate classical dynamics simulations for the liquid phase. For metallic materials such as titanium and aluminum alloys, these calculations are very valuable due to an increasing demand for the knowledge of their thermophysical properties that drive the development of new materials. For example, alongside knowledge of the surface tension, viscosity is an important input for modeling the additive manufacturing process at the continuum level. We are developing calculations of the viscosity along with the self-diffusion for aluminum, titanium, and titanium-aluminum alloys with ab initio molecular dynamics. Supported by the National Science Foundation through cooperative agreement OIA-1541079 and the Louisiana Board of Regents.

[Prognostic scores for pulmonary embolism].

Science.gov (United States)

Junod, Alain

2016-03-23

Nine prognostic scores for pulmonary embolism (PE), based on retrospective and prospective studies, published between 2000 and 2014, have been analyzed and compared. Most of them aim at identifying PE cases with a low risk to validate their ambulatory care. Important differences in the considered outcomes: global mortality, PE-specific mortality, other complications, sizes of low risk groups, exist between these scores. The most popular score appears to be the PESI and its simplified version. Few good quality studies have tested the applicability of these scores to PE outpatient care, although this approach tends to already generalize in the medical practice.

(4)He Thermophysical Properties: New Ab Initio Calculations.

Science.gov (United States)

Hurly, John J; Mehl, James B

2007-01-01

Since 2000, atomic physicists have reduced the uncertainty of the helium-helium "ab initio" potential; for example, from approximately 0.6 % to 0.1 % at 4 bohr, and from 0.8 % to 0.1 % at 5.6 bohr. These results led us to: (1) construct a new inter-atomic potential ϕ 07, (2) recalculate values of the second virial coefficient, the viscosity, and the thermal conductivity of (4)He from 1 K to 10,000 K, and (3), analyze the uncertainties of the thermophysical properties that propagate from the uncertainty of ϕ 07 and from the Born-Oppenheimer approximation of the electron-nucleon quantum mechanical system. We correct minor errors in a previous publication [J. J. Hurly and M. R. Moldover, J. Res. Nat. Inst. Standards Technol. 105, 667 (2000)] and compare our results with selected data published after 2000. The ab initio results tabulated here can serve as standards for the measurement of thermophysical properties.

Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms

Science.gov (United States)

Chan, Garnet Kin-Lic; Keselman, Anna; Nakatani, Naoki; Li, Zhendong; White, Steven R.

2016-07-01

Current descriptions of the ab initio density matrix renormalization group (DMRG) algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational parallelism. The connections and correspondences described here serve to link the future developments with the past and are important in the efficient implementation of continuing advances in ab initio DMRG and related algorithms.

Identify High-Quality Protein Structural Models by Enhanced K-Means.

Science.gov (United States)

Wu, Hongjie; Li, Haiou; Jiang, Min; Chen, Cheng; Lv, Qiang; Wu, Chuang

2017-01-01

Background. One critical issue in protein three-dimensional structure prediction using either ab initio or comparative modeling involves identification of high-quality protein structural models from generated decoys. Currently, clustering algorithms are widely used to identify near-native models; however, their performance is dependent upon different conformational decoys, and, for some algorithms, the accuracy declines when the decoy population increases. Results. Here, we proposed two enhanced K -means clustering algorithms capable of robustly identifying high-quality protein structural models. The first one employs the clustering algorithm SPICKER to determine the initial centroids for basic K -means clustering ( SK -means), whereas the other employs squared distance to optimize the initial centroids ( K -means++). Our results showed that SK -means and K -means++ were more robust as compared with SPICKER alone, detecting 33 (59%) and 42 (75%) of 56 targets, respectively, with template modeling scores better than or equal to those of SPICKER. Conclusions. We observed that the classic K -means algorithm showed a similar performance to that of SPICKER, which is a widely used algorithm for protein-structure identification. Both SK -means and K -means++ demonstrated substantial improvements relative to results from SPICKER and classical K -means.

QUASAR--scoring and ranking of sequence-structure alignments.

Science.gov (United States)

Birzele, Fabian; Gewehr, Jan E; Zimmer, Ralf

2005-12-15

Sequence-structure alignments are a common means for protein structure prediction in the fields of fold recognition and homology modeling, and there is a broad variety of programs that provide such alignments based on sequence similarity, secondary structure or contact potentials. Nevertheless, finding the best sequence-structure alignment in a pool of alignments remains a difficult problem. QUASAR (quality of sequence-structure alignments ranking) provides a unifying framework for scoring sequence-structure alignments that aids finding well-performing combinations of well-known and custom-made scoring schemes. Those scoring functions can be benchmarked against widely accepted quality scores like MaxSub, TMScore, Touch and APDB, thus enabling users to test their own alignment scores against 'standard-of-truth' structure-based scores. Furthermore, individual score combinations can be optimized with respect to benchmark sets based on known structural relationships using QUASAR's in-built optimization routines.

Ab Initio Predictions of Structures and Densities of Energetic Solids

National Research Council Canada - National Science Library

Rice, Betsy M; Sorescu, Dan C

2004-01-01

We have applied a powerful simulation methodology known as ab initio crystal prediction to assess the ability of a generalized model of CHNO intermolecular interactions to predict accurately crystal...

Inelastic neutron scattering an ab-initio calculation of negative thermal expansion in Ag2O

International Nuclear Information System (INIS)

Gupta, M.K.; Mittal, R.; Rols, S.; Chaplot, S.L.

2012-01-01

The compound Ag 2 O undergoes large and isotropic negative thermal expansion over 0-500 K. We report temperature dependent inelastic neutron scattering measurements and ab-initio calculations of the phonon spectrum. The temperature dependence of the experimental phonon spectrum shows strong anharmonic nature of phonon modes of energy around 2.4 meV. The ab-initio calculations reveal that the maximum negative Grüneisen parameter, which is a measure of the relevant anharmonicity, occurs for the transverse phonon modes that involve bending motions of the Ag 4 O tetrahedra. The thermal expansion is evaluated from the ab-initio calculation of the pressure dependence of the phonon modes, and found in good agreement with available experimental data.

Incorporating Learning Characteristics into Automatic Essay Scoring Models: What Individual Differences and Linguistic Features Tell Us about Writing Quality

Science.gov (United States)

Crossley, Scott A.; Allen, Laura K.; Snow, Erica L.; McNamara, Danielle S.

2016-01-01

This study investigates a novel approach to automatically assessing essay quality that combines natural language processing approaches that assess text features with approaches that assess individual differences in writers such as demographic information, standardized test scores, and survey results. The results demonstrate that combining text…

Quality of Life Score as a Predictor of Death in Dogs with Degenerative Mitral Valve Disease.

Science.gov (United States)

Strunz, Célia M C; Marcondes-Santos, Mário; Takada, Julio Yoshio; Fragata, Fernanda S; Mansur, Antônio de Pádua

2017-04-01

The knowledge of the variables predicting mortality is important in clinical practice and for therapeutic monitoring in mitral valve disease. To determine whether a quality of life score evaluated with the Functional Evaluation of Cardiac Health questionnaire would predict mortality in dogs with degenerative mitral valve disease (DMVD). Thirty-six client-owned dogs with mitral valve disease underwent clinical, laboratory, and echocardiographic evaluations at baseline and were monitored for 6 months. Cardiovascular death was the primary outcome. The 36 dogs were classified as survivors or nonsurvivors. Higher values of the following variables were obtained at baseline in the nonsurviving group (12 dogs): amino-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, plasma norepinephrine, heart rate, quality of life score, diastolic left ventricular internal dimension to aortic root ratio, systolic left ventricular internal dimension to aortic root ratio, and left atrium to aortic root ratio. NT-proBNP levels and quality life score were independently associated with death in the multivariable analysis. The quality life score was an independent variable for cardiac death in dogs with DMVD. This result is encouraging, as this score is easy to apply and does not require any technology, only a veterinarian and an observant owner. O conhecimento das variáveis preditoras de mortalidade é importante para a prática clínica e para o acompanhamento terapêutico na doença da valva mitral. Determinar se um escore de qualidade de vida avaliado com o Functional Evaluation of Cardiac Health poderia auxiliar na predição de mortalidade em cães com doença degenerativa da valva mitral (DDVM). Trinta e seis cães de estimação com doença valvar mitral foram submetidos a avaliação clínica, laboratorial e ecocardiográfica no início do estudo e monitorizados durante 6 meses. A morte cardiovascular foi o desfecho primário. Os 36 cães foram classificados como

Geometry optimization of supersymmetrical molecules in quantum chemical ab-initio calculations

International Nuclear Information System (INIS)

Gruenbichler, H.

1985-01-01

One-dimensional geometry optimizations in ab-initio SCF-calculations are investigated. It is shown, that the well known standard algorithms are sometimes too expensive and can be replaced or accompanied by more recent algorithms. Two alternatives were realized in the molecule calculating program GAUSSIAN 80, basing on the Fibonacci algorithm and Kryachco potential adjustment. The algorithms were compared in terms of accuracy of results, CPU-time used and reliability of the method. The results are presented in various tables, showing the efficiency of the various methods. A survey of the usual model potentials is given and the compatibility with ab-initio data is evaluated. (Author, shortened and translated by A.N.)

Sphinx: merging knowledge-based and ab initio approaches to improve protein loop prediction.

Science.gov (United States)

Marks, Claire; Nowak, Jaroslaw; Klostermann, Stefan; Georges, Guy; Dunbar, James; Shi, Jiye; Kelm, Sebastian; Deane, Charlotte M

2017-05-01

Loops are often vital for protein function, however, their irregular structures make them difficult to model accurately. Current loop modelling algorithms can mostly be divided into two categories: knowledge-based, where databases of fragments are searched to find suitable conformations and ab initio, where conformations are generated computationally. Existing knowledge-based methods only use fragments that are the same length as the target, even though loops of slightly different lengths may adopt similar conformations. Here, we present a novel method, Sphinx, which combines ab initio techniques with the potential extra structural information contained within loops of a different length to improve structure prediction. We show that Sphinx is able to generate high-accuracy predictions and decoy sets enriched with near-native loop conformations, performing better than the ab initio algorithm on which it is based. In addition, it is able to provide predictions for every target, unlike some knowledge-based methods. Sphinx can be used successfully for the difficult problem of antibody H3 prediction, outperforming RosettaAntibody, one of the leading H3-specific ab initio methods, both in accuracy and speed. Sphinx is available at http://opig.stats.ox.ac.uk/webapps/sphinx. deane@stats.ox.ac.uk. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press.

Effects of Diquafosol Ophthalmic Solution on Quality of Life in Dry Eye Assessed Using the Dry Eye-Related Quality-of-Life Score Questionnaire: Effectiveness in Patients While Reading and Using Visual Display Terminals.

Science.gov (United States)

Utsunomiya, Tsugiaki; Kawahara, Atsushi; Hanada, Kazuomi; Yoshida, Akitoshi

2017-08-01

Diquafosol ophthalmic solution improves objective findings in the ocular surface and subjective symptoms in patients with dry eye. The Dry Eye-Related Quality-of-Life Score (DEQS) questionnaire was developed to assess dry eye symptoms and their effects on quality of life. However, because little research using the DEQS has been reported, we evaluated the effects of diquafosol ophthalmic solution on ocular surface findings and quality of life using the DEQS in patients with dry eye. Sixty-three patients with dry eye were assigned to the control group (artificial tears) or diquafosol group. Both groups instilled 1 drop of the solution in both eyes 6 times daily and were evaluated after 2 weeks; the diquafosol group also was instructed to be examined at 1 and 3 months. We evaluated the subjective symptoms using the DEQS, fluorescein staining score, tear film breakup time (BUT), Schirmer testing, and lower tear meniscus height with anterior-segment optical coherence tomography. In the diquafosol group, the fluorescein staining score, BUT, tear meniscus height, and DEQS scores improved significantly compared with before treatment in contrast to the control group. Furthermore, in the diquafosol group, the staining score and BUT improved significantly compared with the control group. Analysis of each DEQS item indicated that diquafosol ophthalmic solution relieved foreign body sensation and problems when reading and using visual display terminals compared with the control group. Diquafosol ophthalmic solution was effective in patients with dry eye, especially those with foreign body sensation and problems when reading and using visual display terminals.

Shear stiffness in nanolaminar Ti3SiC2 challenges ab initio calculations

International Nuclear Information System (INIS)

Kisi, E H; Zhang, J F; Kirstein, O; Riley, D P; Styles, M J; Paradowska, A M

2010-01-01

Nanolaminates such as the M n+1 AX n (MAX) phases are a material class with ab initio derived elasticity tensors published for over 250 compounds. We have for the first time experimentally determined the full elasticity tensor of the archetype MAX phase, Ti 3 SiC 2 , using polycrystalline samples and in situ neutron diffraction. The experimental elastic constants show extreme shear stiffness, with c 44 more than five times greater than expected for an isotropic material. Such shear stiffness is quite rare in hexagonal materials and strongly contradicts the predictions of all published MAX phase elastic constants derived from ab initio calculations. It is concluded that second order properties such as elastic moduli derived from ab initio calculations require careful experimental verification. The diffraction technique used currently provides the only method of verification for the elasticity tensor for the majority of new materials where single crystals are not available. (fast track communication)

Proper construction of ab initio global potential surfaces with accurate long-range interactions

International Nuclear Information System (INIS)

Ho, Tak-San; Rabitz, Herschel

2000-01-01

An efficient procedure based on the reproducing kernel Hilbert space interpolation method is presented for constructing intermolecular potential energy surfaces (PES) using not only calculated ab initio data but also a priori information on long-range interactions. Explicitly, use of the reciprocal power reproducing kernel on the semiinfinite interval [0,∞) yields a set of exact linear relations between dispersion (multipolar) coefficients and PES data points at finite internuclear separations. Consequently, given a combined set of ab initio data and the values of dispersion (multipolar) coefficients, the potential interpolation problem subject to long-range interaction constraints can be solved to render globally smooth, asymptotically accurate ab initio potential energy surfaces. Very good results have been obtained for the one-dimensional He-He potential curve and the two-dimensional Ne-CO PES. The construction of the Ne-CO PES was facilitated by invoking a new reproducing kernel for the angular coordinate based on the optimally stable and shape-preserving Bernstein basis functions. (c) 2000 American Institute of Physics

Virtual synthesis of crystals using ab initio MD: Case study on LiFePO4

Science.gov (United States)

Mishra, S. B.; Nanda, B. R. K.

2017-05-01

Molecular dynamics simulation technique is fairly successful in studying the structural aspects and dynamics of fluids. Here we study the ability of ab initio molecular dynamics (ab initio MD) to carry out virtual experiments to synthesize new crystalline materials and to predict their structures. For this purpose the olivine phosphate LiFePO4 (LFPO) is used as an example. As transition metal oxides in general are stabilized with layered geometry, we carried out ab initio MD simulations over a hypothetical layered configuration consisting of alternate LiPO2 and FeO2 layers. With intermittent steps of electron minimization, the resulted equilibrium lattice consist of PO4 tetrahedra and distorted Fe-O complexes similar to the one observed in the experimental lattice.

The Mediterranean Diet Score Is More Strongly Associated with Favorable Cardiometabolic Risk Factors over 2 Years Than Other Diet Quality Indexes in Puerto Rican Adults.

Science.gov (United States)

Mattei, Josiemer; Sotos-Prieto, Mercedes; Bigornia, Sherman J; Noel, Sabrina E; Tucker, Katherine L

2017-04-01

Background: Multiple diet quality scores have been used to evaluate adherence to specific dietary recommendations or to consumption of healthful foods and nutrients. It remains unknown which score can more strongly predict longitudinal changes in cardiometabolic risk factors. Objective: We aimed to determine associations of 5 diet quality scores [AHA diet score (AHA-DS), Dietary Approaches to Stop Hypertension (DASH), Healthy Eating Index (HEI)-2005, Mediterranean diet score (MeDS), and Alternative Healthy Eating Index (AHEI)] with 2-y changes in cardiometabolic risk factors in adults 45-75 y old. Methods: Data from the Boston Puerto Rican Health Study were analyzed ( n = 1194). Diet quality scores were calculated from a baseline-validated food-frequency questionnaire. Multivariable-adjusted, repeated-subjects, mixed-effects models, adjusted for baseline measures, estimated associations between each z score and 14 individual cardiometabolic factors measured at 2 y. Results: MeDS was significantly associated with lower 2-y waist circumference (β coefficient ± SE: -0.52 ± 0.26, P = 0.048); body mass index (BMI; -0.23 ± 0.08, P = 0.005); log-insulin (-0.06 ± 0.02, P = 0.005); log-homeostasis model assessment of insulin resistance (HOMA-IR; -0.05 ± 0.02, P = 0.030), and log-C-reactive protein (-0.13 ± 0.03, P = 0.0002). Similar but weaker associations were observed for the AHEI with BMI, insulin, and HOMA-IR. The AHA-DS was inversely associated with BMI (-0.17 ± 0.08, P = 0.033). Neither the HEI-2005 nor DASH was significantly associated with any variable. Traditional Puerto Rican foods consumed by individuals with high MeDSs included vegetables and meats in homemade soups, orange juice, oatmeal, beans and legumes, fish, whole milk, corn oil, and beer. Conclusions: The MeDS comprises food components and scores associated with a favorable cardiometabolic profile over 2 y in Puerto Rican adults. An overall healthy diet may be particularly beneficial for

Computational methods for ab initio detection of microRNAs

Directory of Open Access Journals (Sweden)

Malik eYousef

2012-10-01

Full Text Available MicroRNAs are small RNA sequences of 18-24 nucleotides in length, which serve as templates to drive post transcriptional gene silencing. The canonical microRNA pathway starts with transcription from DNA and is followed by processing via the Microprocessor complex, yielding a hairpin structure. Which is then exported into the cytosol where it is processed by Dicer and then incorporated into the RNA induced silencing complex. All of these biogenesis steps add to the overall specificity of miRNA production and effect. Unfortunately, their modes of action are just beginning to be elucidated and therefore computational prediction algorithms cannot model the process but are usually forced to employ machine learning approaches. This work focuses on ab initio prediction methods throughout; and therefore homology-based miRNA detection methods are not discussed. Current ab initio prediction algorithms, their ties to data mining, and their prediction accuracy are detailed.

Large-scale ab initio configuration interaction calculations for light nuclei

International Nuclear Information System (INIS)

Maris, Pieter; Potter, Hugh; Vary, James P; Aktulga, H Metin; Ng, Esmond G; Yang Chao; Caprio, Mark A; Çatalyürek, Ümit V; Saule, Erik; Oryspayev, Dossay; Sosonkina, Masha; Zhou Zheng

2012-01-01

In ab-initio Configuration Interaction calculations, the nuclear wavefunction is expanded in Slater determinants of single-nucleon wavefunctions and the many-body Schrodinger equation becomes a large sparse matrix problem. The challenge is to reach numerical convergence to within quantified numerical uncertainties for physical observables using finite truncations of the infinite-dimensional basis space. We discuss strategies for constructing and solving the resulting large sparse matrix eigenvalue problems on current multicore computer architectures. Several of these strategies have been implemented in the code MFDn, a hybrid MPI/OpenMP Fortran code for ab-initio nuclear structure calculations that can scale to 100,000 cores and more. Finally, we will conclude with some recent results for 12 C including emerging collective phenomena such as rotational band structures using SRG evolved chiral N3LO interactions.

The relationship between observer-based toxicity scoring and patient assessed symptom severity after treatment for head and neck cancer. A correlative cross sectional study of the DAHANCA toxicity scoring system and the EORTC quality of life questionnaires

International Nuclear Information System (INIS)

Jensen, Kenneth; Bonde Jensen, Anders; Grau, Cai

2006-01-01

Background and purpose: Morbidity is an important issue in cancer research. The observer-based toxicity scoring system used by DAHANCA (the Danish head and neck cancer study group) has proved itself sensitive to differences in toxicity in a large randomised study, but like other toxicity scoring systems it has not been formally validated. Conversely, the EORTC quality of life questionnaire (QLQ) has been validated as a tool for collecting information about the consequences of disease and treatment on the well being of cancer patients. The purpose of this study was to examine the relationship between the two methods of side effect recording. Patients and methods: One hundred and sixteen recurrence free patients with laryngeal (n=44), pharyngeal (n=34) and oral cavity (n=38) cancer attending follow-up after radiotherapy (n=83) or surgery (n=33) completed EORTC C30, the core questionnaire concerning general symptoms and function and EORTC H and N35 the head and neck specific questionnaire. The attending physicians in the follow-up clinic evaluated and recorded DAHANCA toxicity scores on the same patients. Results: The DAHANCA toxicity scoring system and the EORTC QLQ correlated with several clinical endpoints. The conceptually similar endpoints of the two methods correlated significantly. The objective endpoints of the DAHANCA scoring system were only correlated with quality of life endpoints to a very low degree. The DAHANCA toxicity scores had a low sensitivity (0.48-0.74) in detecting equivalent subjective complaints from the questionnaires and the observer-based scoring system severely underestimated patient complaints. A specific patient group where the DAHANCA score had a higher tendency to fail could not be detected. Conclusion: The DAHANCA toxicity score is an effective instrument in assessing objective treatment induced toxicity in head and neck cancer patients but insensitive and non-specific with regard to patient assessed subjective endpoints. This

Ab initio calculations and modelling of atomic cluster structure

DEFF Research Database (Denmark)

Solov'yov, Ilia; Lyalin, Andrey G.; Solov'yov, Andrey V.

2004-01-01

The optimized structure and electronic properties of small sodium and magnesium clusters have been investigated using it ab initio theoretical methods based on density-functional theory and post-Hartree-Fock many-body perturbation theory accounting for all electrons in the system. A new theoretical...

Modeling of nuclear glasses by classical and ab initio molecular dynamics

International Nuclear Information System (INIS)

Ganster, P.

2004-01-01

A calcium aluminosilicate glass of molar composition 67 % SiO 2 - 12 % Al 2 O 3 - 21 % CaO was modelled by classical and ab initio molecular dynamics. The size effect study in classical MD shows that the systems of 100 atoms are more ordered than the larger ones. These effects are mainly due to the 3-body terms in the empirical potentials. Nevertheless, these effects are small and the structures generated are in agreement with experimental data. In such kind of glass, we denote an aluminium avoidance and an excess of non bridging oxygens which can be compensated by tri-coordinated oxygens. When the dynamics of systems of 100 and 200 atoms is followed by ab initio MD, some local arrangements occurs (bond length, angular distributions). Thus, more realistic vibrational properties are obtained in ab initio MD. The modelling of thin films shows that aluminum atoms extend to the most external part of the surface and they are all tri-coordinated. Calcium atoms are set in the sub layer part of the surface and they produce a depolymerization of the network. In classical MD, tri-coordinated aluminium atoms produce an important electric field above the surface. With non bridging oxygens, they constitute attractive sites for single water molecules. (author) [fr

Modelling of nuclear glasses by classical and ab initio molecular dynamics

International Nuclear Information System (INIS)

Ganster, P.

2004-10-01

A calcium aluminosilicate glass of molar composition 67 % SiO 2 - 12 % Al 2 O 3 - 21 % CaO was modelled by classical and ab initio molecular dynamics. The size effect study in classical MD shows that the systems of 100 atoms are more ordered than the larger ones. These effects are mainly due to the 3-body terms in the empirical potentials. Nevertheless, these effects are small and the structures generated are in agreement with experimental data. In such kind of glass, we denote an aluminium avoidance and an excess of non bridging oxygens which can be compensated by tri coordinated oxygens. When the dynamics of systems of 100 and 200 atoms is followed by ab initio MD, some local arrangements occurs (bond length, angular distributions). Thus, more realistic vibrational properties are obtained in ab initio MD. The modelling of thin films shows that aluminium atoms extend to the most external part of the surface and they are all tri-coordinated. Calcium atoms are set in the sub layer part of the surface and they produce a depolymerization of the network. In classical MD, tri-coordinated aluminium atoms produce an important electric field above the surface. With non bridging oxygens, they constitute attractive sites for single water molecules. (author)

Exploring the speed and performance of molecular replacement with AMPLE using QUARK ab initio protein models

Energy Technology Data Exchange (ETDEWEB)

Keegan, Ronan M. [STFC Rutherford Appleton Laboratory, Didcot OX11 0FA (United Kingdom); Bibby, Jaclyn; Thomas, Jens [University of Liverpool, Liverpool L69 7ZB (United Kingdom); Xu, Dong [Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037 (United States); Zhang, Yang [University of Michigan, Ann Arbor, MI 48109 (United States); Mayans, Olga [University of Liverpool, Liverpool L69 7ZB (United Kingdom); Winn, Martyn D. [Science and Technology Facilities Council Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Rigden, Daniel J., E-mail: drigden@liv.ac.uk [University of Liverpool, Liverpool L69 7ZB (United Kingdom); STFC Rutherford Appleton Laboratory, Didcot OX11 0FA (United Kingdom)

2015-02-01

Two ab initio modelling programs solve complementary sets of targets, enhancing the success of AMPLE with small proteins. AMPLE clusters and truncates ab initio protein structure predictions, producing search models for molecular replacement. Here, an interesting degree of complementarity is shown between targets solved using the different ab initio modelling programs QUARK and ROSETTA. Search models derived from either program collectively solve almost all of the all-helical targets in the test set. Initial solutions produced by Phaser after only 5 min perform surprisingly well, improving the prospects for in situ structure solution by AMPLE during synchrotron visits. Taken together, the results show the potential for AMPLE to run more quickly and successfully solve more targets than previously suspected.

Interobserver agreement and performance score comparison in quality control using a breast phantom: screen-film mammography vs computed radiography

International Nuclear Information System (INIS)

Shimamoto, Kazuhiro; Ikeda, Mitsuru; Satake, Hiroko; Ishigaki, Satoko; Sawaki, Akiko; Ishigaki, Takeo

2002-01-01

Our objective was to evaluate interobserver agreement and to compare the performance score in quality control of screen-film mammography and computed radiography (CR) using a breast phantom. Eleven radiologists interpreted a breast phantom image (CIRS model X) by four viewing methods: (a) original screen-film; (b) soft-copy reading of the digitized film image; (c) hard-copy reading of CR using an imaging plate; and (d) soft-copy reading of CR. For the soft-copy reading, a 17-in. CRT monitor (1024 x 1536 x 8 bits) was used. The phantom image was evaluated using a scoring system outlined in the instruction manual, and observers judged each object using a three-point rating scale: (a) clearly seen; (b) barely seen; and (c) not seen. For statistical analysis, the kappa statistic was employed. For ''mass'' depiction, interobserver agreement using CR was significantly lower than when using screen-film (p<0.05). There was no significant difference in the kappa value for detecting ''microcalcification''; however, the performance score of ''microcalcification'' on CR hard-copy was significantly lower than on the other three viewing methods (p<0.05). Viewing methods (film or CR, soft-copy or hard-copy) could affect how the phantom image is judged. Paying special attention to viewing conditions is recommended for quality control of CR mammograms. (orig.)

Self-Evaluation Scores of Hearing Difficulties and Quality of Life Components among Retired Workers with Noise-Related Hearing Loss

Science.gov (United States)

MIYAKITA, T.; UEDA, A.; ZUSHO, H.; KUDOH, Y.

2002-02-01

This study is intended to clarify the relationships between hearing loss caused both by noise exposure and aging and self-rated scores of hearing disabilities and to elucidate the structure of the quality of life (QOL) determinants and their moderating conditions among retired workers with noise-related hearing loss. The questionnaire consisted of three parts: background questions, the hearing disabilities and handicap scale (HDHS), and questions regarding QOL covering five areas, self-rated health, personal health practice, social support network, life satisfaction, and life events. Two hundred ten retired workers aged 56-65 years old (60·6±1·6) with noise-related hearing loss responded to our questionnaire. All were previously engaged in noise exposed work such as shipbuilding, steel and woodwork. According to the hearing disability score (DIS score), subjects were divided into three groups and comparisons were made of the hearing handicap score (HD score) among those groups. Although groups with a higher DIS score showed a higher HD score, a large individual difference in HD score was observed in each of the three groups with the same DIS score level. The results of multiple regression analysis including two variables (life satisfaction and HD score) as the dependent variables and seven variables as the independent variables showed that the strongest explanatory variable for life satisfaction was social support network, followed by handicaps caused by hearing disabilities, self-rated health and personal health practice. It was demonstrated that hearing disabilities and handicap measured by the Japanese version of the HDHS were directly associated with the deterioration in QOL. Measures of the social support network, life satisfaction, and hearing disabilities and handicaps may assist in the detection of workers who can be targeted for a variety of interventions, such as audiological rehabilitation or the creation of a barrier-free community that is supportive

Ab initio results for intermediate-mass, open-shell nuclei

Science.gov (United States)

Baker, Robert B.; Dytrych, Tomas; Launey, Kristina D.; Draayer, Jerry P.

2017-01-01

A theoretical understanding of nuclei in the intermediate-mass region is vital to astrophysical models, especially for nucleosynthesis. Here, we employ the ab initio symmetry-adapted no-core shell model (SA-NCSM) in an effort to push first-principle calculations across the sd-shell region. The ab initio SA-NCSM's advantages come from its ability to control the growth of model spaces by including only physically relevant subspaces, which allows us to explore ultra-large model spaces beyond the reach of other methods. We report on calculations for 19Ne and 20Ne up through 13 harmonic oscillator shells using realistic interactions and discuss the underlying structure as well as implications for various astrophysical reactions. This work was supported by the U.S. NSF (OCI-0904874 and ACI -1516338) and the U.S. DOE (DE-SC0005248), and also benefitted from the Blue Waters sustained-petascale computing project and high performance computing resources provided by LSU.

Ab initio theory and calculations of X-ray spectra

International Nuclear Information System (INIS)

Rehr, J.J.; Kas, J.J.; Prange, M.P.; Sorini, A.P.; Takimoto, Y.; Vila, F.

2009-01-01

There has been dramatic progress in recent years both in the calculation and interpretation of various x-ray spectroscopies. However, current theoretical calculations often use a number of simplified models to account for many-body effects, in lieu of first principles calculations. In an effort to overcome these limitations we describe in this article a number of recent advances in theory and in theoretical codes which offer the prospect of parameter free calculations that include the dominant many-body effects. These advances are based on ab initio calculations of the dielectric and vibrational response of a system. Calculations of the dielectric function over a broad spectrum yield system dependent self-energies and mean-free paths, as well as intrinsic losses due to multielectron excitations. Calculations of the dynamical matrix yield vibrational damping in terms of multiple-scattering Debye-Waller factors. Our ab initio methods for determining these many-body effects have led to new, improved, and broadly applicable x-ray and electron spectroscopy codes. (authors)

Ab Initio Many-Body Calculations Of Nucleon-Nucleus Scattering

Energy Technology Data Exchange (ETDEWEB)

Quaglioni, S; Navratil, P

2008-12-17

We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translational symmetry and Pauli principle. We outline technical details and present phase shift results for neutron scattering on {sup 3}H, {sup 4}He and {sup 10}Be and proton scattering on {sup 3,4}He, using realistic nucleon-nucleon (NN) potentials. Our A = 4 scattering results are compared to earlier ab initio calculations. We find that the CD-Bonn NN potential in particular provides an excellent description of nucleon-{sup 4}He S-wave phase shifts. We demonstrate that a proper treatment of the coupling to the n-{sup 10}Be continuum is successful in explaining the parity-inverted ground state in {sup 11}Be.

Comparison of the Classifier Oriented Gait Score and the Gait Profile Score based on imitated gait impairments.

Science.gov (United States)

Christian, Josef; Kröll, Josef; Schwameder, Hermann

2017-06-01

Common summary measures of gait quality such as the Gait Profile Score (GPS) are based on the principle of measuring a distance from the mean pattern of a healthy reference group in a gait pattern vector space. The recently introduced Classifier Oriented Gait Score (COGS) is a pathology specific score that measures this distance in a unique direction, which is indicated by a linear classifier. This approach has potentially improved the discriminatory power to detect subtle changes in gait patterns but does not incorporate a profile of interpretable sub-scores like the GPS. The main aims of this study were to extend the COGS by decomposing it into interpretable sub-scores as realized in the GPS and to compare the discriminative power of the GPS and COGS. Two types of gait impairments were imitated to enable a high level of control of the gait patterns. Imitated impairments were realized by restricting knee extension and inducing leg length discrepancy. The results showed increased discriminatory power of the COGS for differentiating diverse levels of impairment. Comparison of the GPS and COGS sub-scores and their ability to indicate changes in specific variables supports the validity of both scores. The COGS is an overall measure of gait quality with increased power to detect subtle changes in gait patterns and might be well suited for tracing the effect of a therapeutic treatment over time. The newly introduced sub-scores improved the interpretability of the COGS, which is helpful for practical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Ab initio multiple cloning algorithm for quantum nonadiabatic molecular dynamics

Energy Technology Data Exchange (ETDEWEB)

Makhov, Dmitry V.; Shalashilin, Dmitrii V. [Department of Chemistry, University of Leeds, Leeds LS2 9JT (United Kingdom); Glover, William J.; Martinez, Todd J. [Department of Chemistry and The PULSE Institute, Stanford University, Stanford, California 94305, USA and SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

2014-08-07

We present a new algorithm for ab initio quantum nonadiabatic molecular dynamics that combines the best features of ab initio Multiple Spawning (AIMS) and Multiconfigurational Ehrenfest (MCE) methods. In this new method, ab initio multiple cloning (AIMC), the individual trajectory basis functions (TBFs) follow Ehrenfest equations of motion (as in MCE). However, the basis set is expanded (as in AIMS) when these TBFs become sufficiently mixed, preventing prolonged evolution on an averaged potential energy surface. We refer to the expansion of the basis set as “cloning,” in analogy to the “spawning” procedure in AIMS. This synthesis of AIMS and MCE allows us to leverage the benefits of mean-field evolution during periods of strong nonadiabatic coupling while simultaneously avoiding mean-field artifacts in Ehrenfest dynamics. We explore the use of time-displaced basis sets, “trains,” as a means of expanding the basis set for little cost. We also introduce a new bra-ket averaged Taylor expansion (BAT) to approximate the necessary potential energy and nonadiabatic coupling matrix elements. The BAT approximation avoids the necessity of computing electronic structure information at intermediate points between TBFs, as is usually done in saddle-point approximations used in AIMS. The efficiency of AIMC is demonstrated on the nonradiative decay of the first excited state of ethylene. The AIMC method has been implemented within the AIMS-MOLPRO package, which was extended to include Ehrenfest basis functions.

Estimating structure quality trends in the Protein Data Bank by equivalent resolution.

Science.gov (United States)

Bagaria, Anurag; Jaravine, Victor; Güntert, Peter

2013-10-01

The quality of protein structures obtained by different experimental and ab-initio calculation methods varies considerably. The methods have been evolving over time by improving both experimental designs and computational techniques, and since the primary aim of these developments is the procurement of reliable and high-quality data, better techniques resulted on average in an evolution toward higher quality structures in the Protein Data Bank (PDB). Each method leaves a specific quantitative and qualitative "trace" in the PDB entry. Certain information relevant to one method (e.g. dynamics for NMR) may be lacking for another method. Furthermore, some standard measures of quality for one method cannot be calculated for other experimental methods, e.g. crystal resolution or NMR bundle RMSD. Consequently, structures are classified in the PDB by the method used. Here we introduce a method to estimate a measure of equivalent X-ray resolution (e-resolution), expressed in units of Å, to assess the quality of any type of monomeric, single-chain protein structure, irrespective of the experimental structure determination method. We showed and compared the trends in the quality of structures in the Protein Data Bank over the last two decades for five different experimental techniques, excluding theoretical structure predictions. We observed that as new methods are introduced, they undergo a rapid method development evolution: within several years the e-resolution score becomes similar for structures obtained from the five methods and they improve from initially poor performance to acceptable quality, comparable with previously established methods, the performance of which is essentially stable. Copyright © 2013 Elsevier Ltd. All rights reserved.

Severity scoring in the critically ill: part 2: maximizing value from outcome prediction scoring systems.

Science.gov (United States)

Breslow, Michael J; Badawi, Omar

2012-02-01

Part 2 of this review of ICU scoring systems examines how scoring system data should be used to assess ICU performance. There often are two different consumers of these data: lCU clinicians and quality leaders who seek to identify opportunities to improve quality of care and operational efficiency, and regulators, payors, and consumers who want to compare performance across facilities. The former need to know how to garner maximal insight into their care practices; this includes understanding how length of stay (LOS) relates to quality, analyzing the behavior of different subpopulations, and following trends over time. Segregating patients into low-, medium-, and high-risk populations is especially helpful, because care issues and outcomes may differ across this severity continuum. Also, LOS behaves paradoxically in high-risk patients (survivors often have longer LOS than nonsurvivors); failure to examine this subgroup separately can penalize ICUs with superior outcomes. Consumers of benchmarking data often focus on a single score, the standardized mortality ratio (SMR). However, simple SMRs are disproportionately affected by outcomes in high-risk patients, and differences in population composition, even when performance is otherwise identical, can result in different SMRs. Future benchmarking must incorporate strategies to adjust for differences in population composition and report performance separately for low-, medium- and high-acuity patients. Moreover, because many ICUs lack the resources to care for high-acuity patients (predicted mortality >50%), decisions about where patients should receive care must consider both ICU performance scores and their capacity to care for different types of patients.

Raman spectroscopy, ab-initio model calculations, and conformational, equilibria in ionic liquids

DEFF Research Database (Denmark)

Berg, Rolf W.

2009-01-01

spectroscopy and ab-initio molecular orbital calculations. A discussion is given, based mainly on some recent FT- Raman spectroscopic results on the model ionic liquid system of 1-butyl-3-methyl-imidazolium ([C4C1Im]+X-) salts. The rotational isomerism of the [C4C1Im]+ cation is described: the presence of anti.......3 Brief introduction to ab-initio model calculations .... 312 12.4 Case study on Raman spectroscopy and structure of imidazolium-based ionic liquids ..... 312 12.5 Raman spectra and structure of [C4C1Im]+ liquids ..... 315 12.6 Normal mode analysis and rotational isomerism of the [C4C1Im]+ cation...

Body Movement Music Score – Introduction of a newly developed model for the analysis and description of body qualities, movement and music in music therapy

Directory of Open Access Journals (Sweden)

Hanna Agnieszka Skrzypek

2017-01-01

Full Text Available Background In music therapy, there is a range of music therapy concepts that, in addition to music, describe and analyse the body and movement. A model that equally examines the body, movement and music has not been developed. The Body Movement Music Score (BMMS is a newly developed and evaluated music therapy model for analysing body qualities, movement, playing style of musical instruments and music and to describe body behaviour and body expression, movement behaviour and movement expression, playing behaviour and musical expression in music therapy treatment. The basis for the development of the Body Movement Music Score was the evaluation of the analytical movement model Emotorics-Emotive Body Movement Mind Paradigm (Emotorics-EBMMP by Yona Shahar Levy for the analysis and description of the emotive-motor behaviour and movement expression of schizophrenic patients in music therapy treatment. Participants and procedure The application of the Body Movement Music Score is presented in a videotaped example from the music therapy treatment of one schizophrenic patient. Results The results of applying the Body Movement Music Score are presented in the form of Body Qualities I Analysis, Body Qualities II Analysis, Movement Analysis, Playing Style Analysis and Music Analysis Profiles. Conclusions The Body Movement Music Score has been developed and evaluated for the music therapy treatment of schizophrenic patients. For the development of the model, a proof of reliability is necessary to verify the reliability and limitations of the model in practice and show that the Body Movement Music Score could be used for both practical and clinical work, for documentation purposes and to impact research in music therapy.

Ab initio assisted process modeling for Si-based nanoelectronic devices

International Nuclear Information System (INIS)

Windl, Wolfgang

2005-01-01

In this paper, we discuss concepts and examples of ab initio calculations assisting physics-based process simulation. We focus on how to determine diffusion and reaction constants, where modern methods such as the nudged elastic band method allow a systematic and reliable search for the minimum energy migration path and barrier. We show that once the saddle point is determined, the underlying harmonic transition state theory also allows to calculate the prefactors. The discussed examples include nitrogen diffusion, boron deactivation and boron interface segregation. Finally, some concepts are discussed for future device technologies such as molecular devices, where the currently prevalent multiscale approach (kinetic parameters used in higher level models like diffusion-reaction or kinetic Monte Carlo modeling) would not be sensible anymore. As an example, we described the ab initio temperature-accelerated dynamics modeling of contact formation in carbon nanotube devices

Ab initio study of phase equilibria in TiCx

DEFF Research Database (Denmark)

Korzhavyi, P.A.; Pourovskii, L.V.; Hugosson, H.W.

2002-01-01

The phase diagram for the vacancy-ordered structures in the substoichiometric TiCx (x = 0.5-1.0) has been established from Monte Carlo simulations with the long-range pair and multisite effective interactions obtained from ab initio calculations. Three ordered superstructures of vacancies (Ti2C, Ti...

Ab initio and empirical studies on the asymmetry of molecular current-voltage characteristics

International Nuclear Information System (INIS)

Hoft, R C; Armstrong, N; Ford, M J; Cortie, M B

2007-01-01

We perform theoretical calculations of the tunnelling current through various small organic molecules sandwiched between gold electrodes by using both a tunnel barrier model and an ab initio transport code. The height of the tunnelling barrier is taken to be the work function of gold as modified by the adsorbed molecule and calculated from an ab initio electronic structure code. The current-voltage characteristics of these molecules are compared. Asymmetry is introduced into the system in two ways: an asymmetric molecule and a gap between the molecule and the right electrode. The latter is a realistic situation in scanning probe experiments. The asymmetry is also realized in the tunnel barrier model by two distinct work functions on the left and right electrodes. Significant asymmetry is observed in the ab initio i(V) curves. The tunnel barrier i(V) curves show much less pronounced asymmetry. The relative sizes of the currents through the molecules are compared. In addition, the performance of the WKB approximation is compared to the results obtained from the exact Schroedinger solution to the tunnelling barrier problem

Investigation of polarization effects in the gramicidin A channel from ab initio molecular dynamics simulations.

Science.gov (United States)

Timko, Jeff; Kuyucak, Serdar

2012-11-28

Polarization is an important component of molecular interactions and is expected to play a particularly significant role in inhomogeneous environments such as pores and interfaces. Here we investigate the effects of polarization in the gramicidin A ion channel by performing quantum mechanics/molecular mechanics molecular dynamics (MD) simulations and comparing the results with those obtained from classical MD simulations with non-polarizable force fields. We consider the dipole moments of backbone carbonyl groups and channel water molecules as well as a number of structural quantities of interest. The ab initio results show that the dipole moments of the carbonyl groups and water molecules are highly sensitive to the hydrogen bonds (H-bonds) they participate in. In the absence of a K(+) ion, water molecules in the channel are quite mobile, making the H-bond network highly dynamic. A central K(+) ion acts as an anchor for the channel waters, stabilizing the H-bond network and thereby increasing their average dipole moments. In contrast, the K(+) ion has little effect on the dipole moments of the neighboring carbonyl groups. The weakness of the ion-peptide interactions helps to explain the near diffusion-rate conductance of K(+) ions through the channel. We also address the sampling issue in relatively short ab initio MD simulations. Results obtained from a continuous 20 ps ab initio MD simulation are compared with those generated by sampling ten windows from a much longer classical MD simulation and running each window for 2 ps with ab initio MD. Both methods yield similar results for a number of quantities of interest, indicating that fluctuations are fast enough to justify the short ab initio MD simulations.

Modelling of nuclear glasses by classical and ab initio molecular dynamics; Modelisation de verres intervenant dans le conditionnement des dechets radioactifs par dynamiques moleculaires classique et ab initio

Energy Technology Data Exchange (ETDEWEB)

Ganster, P

2004-10-15

A calcium aluminosilicate glass of molar composition 67 % SiO{sub 2} - 12 % Al{sub 2}O{sub 3} - 21 % CaO was modelled by classical and ab initio molecular dynamics. The size effect study in classical MD shows that the systems of 100 atoms are more ordered than the larger ones. These effects are mainly due to the 3-body terms in the empirical potentials. Nevertheless, these effects are small and the structures generated are in agreement with experimental data. In such kind of glass, we denote an aluminium avoidance and an excess of non bridging oxygens which can be compensated by tri coordinated oxygens. When the dynamics of systems of 100 and 200 atoms is followed by ab initio MD, some local arrangements occurs (bond length, angular distributions). Thus, more realistic vibrational properties are obtained in ab initio MD. The modelling of thin films shows that aluminium atoms extend to the most external part of the surface and they are all tri-coordinated. Calcium atoms are set in the sub layer part of the surface and they produce a depolymerization of the network. In classical MD, tri-coordinated aluminium atoms produce an important electric field above the surface. With non bridging oxygens, they constitute attractive sites for single water molecules. (author)

Addressing Opioid-Associated Constipation Using Quality Oncology Practice Initiative Scores and Plan-Do-Study-Act Cycles.

Science.gov (United States)

Kaur, Varinder; Haider, Sajjad; Sasapu, Appalanaidu; Mehta, Paulette; Arnaoutakis, Konstantinos; Makhoul, Issam

2017-01-01

Using the Quality Oncology Practice Initiative, an affiliate program of ASCO, we outlined opioid-associated constipation (OAC) as a subject in need of quality improvement (QI) in our fellowship program at the University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System. We initiated a fellow-led QI project to advance the quality of patient care and provide a valuable avenue for QI training of young physicians. Fellows organized meetings with all stakeholders, addressed the scope of the problem, and devised strategies for OAC management. Monthly meetings were organized using Plan-Do-Study-Act principles. Mandatory check boxes were inserted into our electronic medical record templates to remind all physicians to identify patients on opioid medications and assess and address OAC. Final chart audit and patient satisfaction surveys were performed 6 months after project initiation. Assessment of OAC improved from 52% at baseline to 92% ( P < .003). This improvement corresponded with high patient satisfaction scores, with 90% of surveyed patients reporting adequate management of their constipation. In this QI initiative, we showed that participation in ASCO's Quality Oncology Practice Initiative helps identify areas in need of QI, and such fellow-led QI projects can serve as models for QI training of young physicians.

Paediatric early warning scores on a children's ward: a quality improvement initiative.

LENUS (Irish Health Repository)

Ennis, Linda

2014-09-09

The aim of this quality improvement initiative was to incorporate a paediatric early warning score (PEWS) and track and trigger system in the routine care of children in an acute general children\\'s ward at a regional hospital in the Republic of Ireland. In the absence of a nationally recommended specific PEWS strategy, a local plan was developed. The experience of structuring and implementing the PEWS and track and trigger system is presented in this article. Data from the first year of use were collected to evaluate the clinical utility and effectiveness of this system. In the busy acute children\\'s service, the PEWS initiative was found to benefit processes of early detection, prompt referral and timely, appropriate management of children at potential risk of clinical deterioration. Nursing staff were empowered and supported to communicate concerns immediately and to seek rapid medical review, according to an agreed PEWS escalation plan. Outcomes were significantly improved.

Quantifying transition voltage spectroscopy of molecular junctions: Ab initio calculations

DEFF Research Database (Denmark)

Chen, Jingzhe; Markussen, Troels; Thygesen, Kristian Sommer

2010-01-01

Transition voltage spectroscopy (TVS) has recently been introduced as a spectroscopic tool for molecular junctions where it offers the possibility to probe molecular level energies at relatively low bias voltages. In this work we perform extensive ab initio calculations of the nonlinear current...

Ab Initio Calculations for the BaTiO3 (001) Surface Structure

Institute of Scientific and Technical Information of China (English)

XUE Xu-Yan; WANG Chun-Lei; ZHONG Wei-Lie

2004-01-01

@@ The ab initio method within the local density approximation is applied to calculate cubic BaTiO3 (001) surface relaxation and rumpling for two different terminations (BaO and TiO2). Our calculations demonstrate that cubic perovskite BaTiO3 crystals possess surface polarization, accompanied by the presence of the relevant electric field.We analyse their electronic structures (band structure, density of states and the electronic density redistribution with emphasis on the covalency effects). The results are also compared with that of the previous ab initio calculations. Considerable increases of Ti-O chemical bond covalency nearby the surface have been observed.The band gap reduces especially for the TiO2 termination.

Index admission laparoscopic cholecystectomy for acute cholecystitis restores Gastrointestinal Quality of Life Index (GIQLI) score.

Science.gov (United States)

Yu, Hongyan; Chan, Esther Ern-Hwei; Lingam, Pravin; Lee, Jingwen; Woon, Winston Wei Liang; Low, Jee Keem; Shelat, Vishal G

2018-02-01

Previous studies have evaluated quality of life (QoL) in patients who underwent laparoscopic cholecystectomy (LC) for cholelithiasis. The purpose of this study was to evaluate QoL after index admission LC in patients diagnosed with acute cholecystitis (AC) using the Gastrointestinal Quality of Life Index (GIQLI) questionnaire. Patients ≥21 years admitted to Tan Tock Seng Hospital, Singapore for AC and who underwent index admission LC between February 2015 and January 2016 were evaluated using the GIQLI questionnaire preoperatively and 30 days postoperatively. A total of 51 patients (26 males, 25 females) with a mean age of 60 years (24-86 years) were included. Median duration of abdominal pain at presentation was 2 days (1-21 days). 45% of patients had existing comorbidities, with diabetes mellitus being most common (33%). 31% were classified as mild AC, 59% as moderate and 10% as severe AC according to Tokyo Guideline 2013 (TG13) criteria. Post-operative complications were observed in 8 patients, including retained common bile duct stone (n=1), wound infection (n=2), bile leakage (n=2), intra-abdominal collection (n=1) and atrial fibrillation (n=2). 86% patients were well at 30 days follow-up and were discharged. A significant improvement in GIQLI score was observed postoperatively, with mean total GIQLI score increasing from 106.0±16.9 (101.7-112.1) to 120.4±18.0 (114.8-125.9) ( p <0.001). Significant improvements were also observed in GIQLI subgroups of gastrointestinal symptoms, physical status, emotional status and social function status. Index admission LC restores QoL in patients with AC as measured by GIQLI questionnaire.

Permanent and induced dipole requirements in ab initio calculations of electron affinities of polar molecules

International Nuclear Information System (INIS)

Garrett, W.R.

1979-01-01

Through the use of a molecular pseudopotential method, we determine the a approximate magnitudes of errors that result when electron affinity determinations of polar negative ions are made through ab initio calculations in which the use of a given basis set yields inappropriate values for permanent and induced dipole moments of the neutral molecule. These results should prove useful in assessing the adequacy of basis sets in ab initio calculations of molecular electron affinities for simple linear polar molecules

Ab initio/interpolated quantum dynamics on coupled electronic states with full configuration interaction wave functions

International Nuclear Information System (INIS)

Thompson, K.; Martinez, T.J.

1999-01-01

We present a new approach to first-principles molecular dynamics that combines a general and flexible interpolation method with ab initio evaluation of the potential energy surface. This hybrid approach extends significantly the domain of applicability of ab initio molecular dynamics. Use of interpolation significantly reduces the computational effort associated with the dynamics over most of the time scale of interest, while regions where potential energy surfaces are difficult to interpolate, for example near conical intersections, are treated by direct solution of the electronic Schroedinger equation during the dynamics. We demonstrate the concept through application to the nonadiabatic dynamics of collisional electronic quenching of Li(2p). Full configuration interaction is used to describe the wave functions of the ground and excited electronic states. The hybrid approach agrees well with full ab initio multiple spawning dynamics, while being more than an order of magnitude faster. copyright 1999 American Institute of Physics

Common lines modeling for reference free Ab-initio reconstruction in cryo-EM.

Science.gov (United States)

Greenberg, Ido; Shkolnisky, Yoel

2017-11-01

We consider the problem of estimating an unbiased and reference-free ab initio model for non-symmetric molecules from images generated by single-particle cryo-electron microscopy. The proposed algorithm finds the globally optimal assignment of orientations that simultaneously respects all common lines between all images. The contribution of each common line to the estimated orientations is weighted according to a statistical model for common lines' detection errors. The key property of the proposed algorithm is that it finds the global optimum for the orientations given the common lines. In particular, any local optima in the common lines energy landscape do not affect the proposed algorithm. As a result, it is applicable to thousands of images at once, very robust to noise, completely reference free, and not biased towards any initial model. A byproduct of the algorithm is a set of measures that allow to asses the reliability of the obtained ab initio model. We demonstrate the algorithm using class averages from two experimental data sets, resulting in ab initio models with resolutions of 20Å or better, even from class averages consisting of as few as three raw images per class. Copyright © 2017 Elsevier Inc. All rights reserved.

Reporting health-related quality of life scores to physicians during routine follow-up visits of pediatric oncology patients: Is it effective?

NARCIS (Netherlands)

Engelen, Vivian; Detmar, Symone; Koopman, Hendrik; Maurice-Stam, Heleen; Caron, Huib; Hoogerbrugge, Peter; Egeler, R. Maarten; Kaspers, Gertjan; Grootenhuis, Martha

2012-01-01

Background The aim of the current study is to investigate the effectiveness of an intervention that provides health-related quality of life (HRQOL) scores of the patient (the QLIC-ON PROfile) to the pediatric oncologist. Procedure. Children with cancer participated in a sequential cohort

Reporting health-related quality of life scores to physicians during routine follow-up visits of pediatric oncology patients: Is it effective?

NARCIS (Netherlands)

Engelen, V.; Detmar, S.; Koopman, H.; Maurice-Stam, H.; Caron, H.; Hoogerbrugge, P.; Egeler, R.M.; Kaspers, G.; Grootenhuis, M.

2012-01-01

Background: The aim of the current study is to investigate the effectiveness of an intervention that provides health-related quality of life (HRQOL) scores of the patient (the QLIC-ON PROfile) to the pediatric oncologist. Procedure: Children with cancer participated in a sequential cohort

Clinical observation on scores of anxiety, depression and quality of life for advanced gastrointestinal carcinoma patients with palliation intervention therapy

International Nuclear Information System (INIS)

Chen Yue; Jiang Tinghui; Jiang Yongxing; Sun Xianjun

2007-01-01

Objective: To evaluate the influence of palliative intervention therapy on advanced gastrointestinal carcinoma patients with depression and anxiety before and after the treatment. Methods: 56 advanced gastrointestinal carcinoma patients were selected and treated with intra-arterial perfusion chemotherapy or intra-arterial perfusion chemotherapy with embolization. Curative effects were assessed with the SDS, SAS and FACT-G before and after the treatment. In addition, all patients took self-assessment with SCL-90, comparing with the Chinese norms. Results: SCL-90 scores including the somatization agent, depression agent, and anxiety agent scores of the advanced gastrointestinal carcinoma were higher than those of Chinese norms, with significant difference (P<0.05). After palliative intervention therapy, the scores of SDS and SAS were lower than those before the palliative intervention therapy with significant difference (P< 0.05); and furthermore with an obvious improvement in the scores of FACT-G (P<0.05). Conclusion: Palliative intervention therapy for advanced gastrointestinal carcinoma patients can improve the complaints of depression anxiety and quality of life. (authors)

Early stage precipitation in aluminum alloys : An ab initio study

NARCIS (Netherlands)

Zhang, X.

2017-01-01

Multiscale computational materials science has reached a stage where many complicated phenomena or properties that are of great importance to manufacturing can be predicted or explained. The word “ab initio study” becomes commonplace as the development of density functional theory has enabled the

Ab initio electronic properties of dual phosphorus monolayers in silicon

DEFF Research Database (Denmark)

Drumm, Daniel W.; Per, Manolo C.; Budi, Akin

2014-01-01

In the midst of the epitaxial circuitry revolution in silicon technology, we look ahead to the next paradigm shift: effective use of the third dimension - in particular, its combination with epitaxial technology. We perform ab initio calculations of atomically thin epitaxial bilayers in silicon...

PASI and PQOL-12 score in psoriasis : Is there any correlation?

Directory of Open Access Journals (Sweden)

Vikas Shankar

2011-01-01

Full Text Available Background: Psoriasis, a common papulo-squamous disorder of the skin, is universal in occurrence and may interfere with the quality of life adversely. Whether extent of the disease has any bearing upon the patients′ psychology has not much been studied in this part of the world. Aims: The objective of this hospital-based cross-sectional study was to assess the disease severity objectively using Psoriasis area and severity index (PASI score and the quality of life by Psoriasis quality-of-life questionnaire-12 (PQOL-12 and to draw correlation between them, if any. Materials and Methods PASI score denotes an objective method of scoring severity of psoriasis, reflecting not only the body surface area but also erythema, induration and scaling. The PQOL-12 represents a 12-item self-administered, disease-specific psychometric instrument created to specifically assess quality-of-life issues that are more important with psoriasis patients. PASI and PQOL-12 score were calculated in each patient for objectively assessing their disease severity and quality of life. Results: In total, 34 psoriasis patients (16 males, 18 females, of age ranging from 8 to 55 years, were studied. Maximum and minimum PASI scores were 0.8 and 32.8, respectively, whereas maximum and minimum PQOL-12 scores were 4 and 120, respectively. PASI and PQOL-12 values showed minimal positive correlation (r = +0.422. Conclusion: Disease severity of psoriasis had no direct reflection upon their quality of life. Limited psoriasis on visible area may also have greater impact on mental health.

Ab initio calculations of mechanical properties: Methods and applications

Czech Academy of Sciences Publication Activity Database

Pokluda, J.; Černý, Miroslav; Šob, Mojmír; Umeno, Y.

2015-01-01

Roč. 73, AUG (2015), s. 127-158 ISSN 0079-6425 R&D Projects: GA ČR(CZ) GAP108/12/0311 Institutional support: RVO:68081723 Keywords : Ab initio methods * Elastic moduli * Intrinsic hardness * Stability analysis * Theoretical strength * Intrinsic brittleness/ductility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 31.083, year: 2015

Iron -chromium alloys and free surfaces: from ab initio calculations to thermodynamic modeling

International Nuclear Information System (INIS)

Levesque, M.

2010-11-01

Ferritic steels possibly strengthened by oxide dispersion are candidates as structural materials for generation IV and fusion nuclear reactors. Their use is limited by incomplete knowledge of the iron-chromium phase diagram at low temperatures and of the phenomena inducing preferential segregation of one element at grain boundaries or at surfaces. In this context, this work contributes to the multi-scale study of the model iron-chromium alloy and their free surfaces by numerical simulations. This study begins with ab initio calculations of properties related to the mixture of atoms of iron and chromium. We highlight complex dependency of the magnetic moments of the chromium atoms on their local chemical environment. Surface properties are also proving sensitive to magnetism. This is the case of impurity segregation of chromium in iron and of their interactions near the surface. In a second step, we construct a simple energy model for high numerical efficiency. It is based on pair interactions on a rigid lattice to which are given local chemical environment and temperature dependencies. With this model, we reproduce the ab initio results at zero temperature and experimental results at high temperature. We also deduce the solubility limits at all intermediate temperatures with mean field approximations that we compare to Monte Carlo simulations. The last step of our work is to introduce free surfaces in our model. We then study the effect of ab initio calculated bulk and surface properties on surface segregation.Finally, we calculate segregation isotherms. We therefore propose an evolution model of surface composition of iron-chromium alloys as a function of bulk composition. which are given local chemical environment and temperature dependencies. With this model, we reproduce the ab initio results at zero temperature and experimental results at high temperature. We also deduce the solubility limits at all intermediate temperatures with mean field approximations that

Diet quality of Italian yogurt consumers: an application of the probability of adequate nutrient intake score (PANDiet).

Science.gov (United States)

Mistura, Lorenza; D'Addezio, Laura; Sette, Stefania; Piccinelli, Raffaela; Turrini, Aida

2016-01-01

The diet quality in yogurt consumers and non-consumers was evaluated by applying the probability of adequate nutrient intake (PANDiet) index to a sample of adults and elderly from the Italian food consumption survey INRAN SCAI 2005-06. Overall, yogurt consumers had a significantly higher mean intake of energy, calcium and percentage of energy from total sugars whereas the mean percentage of energy from total fat, saturated fatty acid and total carbohydrate were significantly (p yogurt consumers than in non-consumers, (60.58 ± 0.33 vs. 58.58 ± 0.19, p yogurt consumers. The items of calcium, potassium and riboflavin showed the major percentage variation between consumers and non-consumers. Yogurt consumers were more likely to have adequate intakes of vitamins and minerals, and a higher quality score of the diet.

Preferred 11 different job rotation types in automotive company and their effects on productivity, quality and musculoskeletal disorders: comparison between subjective and actual scores by workers' age.

Science.gov (United States)

Jeon, In Sik; Jeong, Byung Yong; Jeong, Ji Hyun

2016-10-01

This study investigates workers' favoured rotation types by their age and compares means between subjective and actual scores on productivity, quality and musculoskeletal disorders (MSDs). The subjects of research were 422 assembly line units in Hyundai Motor Company. The survey of 422 units focused on the workers' preference for 11 different rotation types and subjective scores for each type's perceived benefits, both by the workers' age. Then, actual scores on production-related indices were traced over a five-year period. The results suggest that different rotation types lead to different results in productivity, product quality and MSDs. Workers tend to perceive job rotation as a helpful method to enhance satisfaction, productivity and product quality more so than the actual production data suggests. Job rotation was especially effective in preventing MSDs for workers aged under 45, while its effects were not clear for the workers aged 45 years or older. Practitioner's Summary: This research presents appropriate rotation type for different age groups. Taking workers' age into account, administrators can use the paper's outcomes to select and implement the suitable rotation type to attain specific goals such as enhancing productivity, improving product quality or reducing MSDs.

Studies of urea geometry by means of ab initio methods and computer simulations of liquids

OpenAIRE

Cirino, José Jair Vianna; Bertran, Celso Aparecido

2002-01-01

A study was carried out on the urea geometries using ab initio calculation and Monte Carlo computational simulation of liquids. The ab initio calculated results showed that urea has a non-planar conformation in the gas phase in which the hydrogen atoms are out of the plane formed by the heavy atoms. Free energies associated to the rotation of the amino groups of urea in water were obtained using the Monte Carlo method in which the thermodynamic perturbation theory is implemented. The magnitud...

Ab initio molecular dynamics simulation of laser melting of silicon

NARCIS (Netherlands)

Silvestrelli, P.-L.; Alavi, A.; Parrinello, M.; Frenkel, D.

1996-01-01

The method of ab initio molecular dynamics, based on finite temperature density functional theory, is used to simulate laser heating of crystal silicon. We have found that a high concentration of excited electrons dramatically weakens the covalent bond. As a result, the system undergoes a melting

Ab initio I-V characteristics of short C-20 chains

DEFF Research Database (Denmark)

Roland, C.; Larade, B.; Taylor, Jeremy Philip

2002-01-01

We have calculated the I-V characteristics of short chains of C-20 molecular cages between Al and Au leads with an ab initio formalism. The results indicate that a linear chain of such molecules acts primarily as metallic nanowires. The transmission, however, depends sensitively both...

Hydrogen Bond Dynamics in Aqueous Solutions: Ab initio Molecular ...

Indian Academy of Sciences (India)

Rate equation for the decay of CHB(t) · Definition of Hydrogen Bonds · Results of Molecular Dynamics · Dynamics of anion-water and water-water hydrogen bonds · Structural relaxation of anion-water & water-water H-bonds · Ab initio Molecular Dynamics : · Slide 14 · Dynamics of hydrogen bonds : CPMD results · Slide 16.

Ab initio quantum chemistry in parallel-portable tools and applications

International Nuclear Information System (INIS)

Harrison, R.J.; Shepard, R.; Kendall, R.A.

1991-01-01

In common with many of the computational sciences, ab initio chemistry faces computational constraints to which a partial solution is offered by the prospect of highly parallel computers. Ab initio codes are large and complex (O(10 5 ) lines of FORTRAN), representing a significant investment of communal effort. The often conflicting requirements of portability and efficiency have been successfully resolved on vector computers by reliance on matrix oriented kernels. This proves inadequate even upon closely-coupled shared-memory parallel machines. We examine the algorithms employed during a typical sequence of calculations. Then we investigate how efficient portable parallel implementations may be derived, including the complex multi-reference singles and doubles configuration interaction algorithm. A portable toolkit, modeled after the Intel iPSC and the ANL-ACRF PARMACS, is developed, using shared memory and TCP/IP sockets. The toolkit is used as an initial platform for programs portable between LANS, Crays and true distributed-memory MIMD machines. Timings are presented. 53 refs., 4 tabs

Materials Screening for the Discovery of New Half-Heuslers: Machine Learning versus ab Initio Methods.

Science.gov (United States)

Legrain, Fleur; Carrete, Jesús; van Roekeghem, Ambroise; Madsen, Georg K H; Mingo, Natalio

2018-01-18

Machine learning (ML) is increasingly becoming a helpful tool in the search for novel functional compounds. Here we use classification via random forests to predict the stability of half-Heusler (HH) compounds, using only experimentally reported compounds as a training set. Cross-validation yields an excellent agreement between the fraction of compounds classified as stable and the actual fraction of truly stable compounds in the ICSD. The ML model is then employed to screen 71 178 different 1:1:1 compositions, yielding 481 likely stable candidates. The predicted stability of HH compounds from three previous high-throughput ab initio studies is critically analyzed from the perspective of the alternative ML approach. The incomplete consistency among the three separate ab initio studies and between them and the ML predictions suggests that additional factors beyond those considered by ab initio phase stability calculations might be determinant to the stability of the compounds. Such factors can include configurational entropies and quasiharmonic contributions.

Examination of the Five Comparable Component Scores of the Diet Quality Indexes HEI-2005 and RC-DQI Using a Nationally Representative Sample of 2–18 Year Old Children: NHANES 2003–2006

Directory of Open Access Journals (Sweden)

Sibylle Kranz

2013-01-01

Full Text Available Obesity has been associated with low diet quality and the suboptimal intake of food groups and nutrients. Two composite diet quality measurement tools are appropriate for Americans 2–18 years old: the Healthy Eating Index (HEI 2005 and the Revised Children’s Diet Quality Index (RC-DQI. The five components included in both indexes are fruits, vegetables, total grains, whole grains, and milk/dairy. Component scores ranged from 0 to 5 or 0 to 10 points with lower scores indicating suboptimal intake. To allow direct comparisons, one component was rescaled by dividing it by 2; then, all components ranged from 0 to 5 points. The aim of this study was to directly compare the scoring results of these five components using dietary data from a nationally representative sample of children (NHANES 2003–2006, . Correlation coefficients within and between indexes showed less internal consistency in the HEI; age- and ethnic-group stratified analyses indicated higher sensitivity of the RC-DQI. HEI scoring was likely to dichotomize the population into two groups (those with 0 and those with 5 points, while RC-DQI scores resulted in a larger distribution of scores. The scoring scheme of diet quality indexes for children results in great variation of the outcomes, and researchers must be aware of those effects.

Analysis of High Quality Agar wood Oil Chemical Compounds By Means Of SPME/ GC-MS and Z-Score Technique

International Nuclear Information System (INIS)

Nurlaila Ismail; Mohd Ali Nor Azah; Mailina Jamil; Saiful Nizam Tajuddin; Mohd Nasir Taib

2013-01-01

Currently, the grading of the agar wood oil to the high and low quality is done using manually such as human trained grader. It was performed based on the agar wood oil physical properties such as human experience and perception and the oil colour, odor and long lasting aroma. Several researchers found that chemical profiles of the oil should be utilized to overcome the problem facing by manual techniques for example human nose cannot tolerate with the many oils at the same time, so that accurate result can be obtained in grading the agar wood oil. The analysis involved of SPME/ GC-MS and Z-score techniques have been proposed in this study to analyze the chemical compounds especially from the high quality samples of agar wood oil (Aquilariamalaccensis) from Malaysia. Two SPME fibers were used such as divinylbenzene-carbogen-polydimethylsiloxane (DVB-CAR-PDMS) and polydimethylsiloxane (PDMS) in extracting the oils compound under three different sampling temperature conditions such as 40, 60 and 80 degree Celsius. The chemical compounds extracted by SPME/ GC-MS were analyzed. The chemical compounds as identified by Z-score as significant compounds were discussed before the conclusion is made. It was found that 10-epi-γ-eudesmol, aromadendrene, β-agar ofuran, α-agar ofuran and γ-eudesmol were highlighted as significant for high quality agar wood oil and can be used as a marker compounds in classifying the agar wood oil. (author)

A Scoring Tool for Websites – A Case of Sustainable Organizations

Directory of Open Access Journals (Sweden)

Ahmed GOMAA

2014-06-01

Full Text Available This paper introduces a scoring tool to analyse company sustainability marketing efforts. We identify the expected scores for the companies selected on Corporate Responsibility Magazine’s list of 100 Best Corporate Citizens of the year. The scoring tool is based on the aspects of sustainability and website quality and is divided into three categories: a user friendly, b transparency, and c content. The automation of the scoring tool benefits from a sustainability taxonomy to extract and evaluate the sustainability concepts and efforts mentioned by the companies. The tool scores the selected companies websites to determine the extent and quality of a company’s marketing of sustainability efforts. The result of applying the scoring tool shows that all companies in the list scored 8 to 14 in the user friendly section. In the transparency section, they scored 5 to 7, and in the content section they scored 6 to 10.

Cyanogen Azide. Ionization Potentials and Ab Initio SCF MO Calculation

DEFF Research Database (Denmark)

Bak, Börge; Jansen, Peter; Stafast, Herbert

1975-01-01

The Ne(I) and He(I) photoelectron(PE) spectra of cyanogen azide, NCN3, have been recorded at high resolution. Their interpretation is achieved by comparison with the PE spectrum of HN3 and an ab initio LCGO SCF MO calculation. Deviations from Koopmans' theorem of quite different magnitudes...

Young Modulus of Crystalline Polyethylene from ab Initio Molecular Dynamics

NARCIS (Netherlands)

Hageman, J.C.L.; Meier, Robert J.; Heinemann, M.; Groot, R.A. de

1997-01-01

The Young modulus for crystalline polyethylene is calculated using ab initio molecular dynamics based on density functional theory in the local density approximation (DFT-LDA). This modulus, which can be seen as the ultimate value for the Young modulus of polyethylene fibers, is found to be 334 GPa.

Ab initio and kinetic modeling studies of formic acid oxidation

DEFF Research Database (Denmark)

Marshall, Paul; Glarborg, Peter

2015-01-01

A detailed chemical kinetic model for oxidation of formic acid (HOCHO) in flames has been developed, based on theoretical work and data from literature. Ab initio calculations were used to obtain rate coefficients for reactions of HOCHO with H, O, and HO2. Modeling predictions with the mechanism...

The Properties of Some Simple Covalent Hydrides: An Ab Initio ...

African Journals Online (AJOL)

Some properties of the monomeric binary hydrides of the elements of the first two rows of the periodic table have been determined using ab initio molecular orbital theory. The properties in question are the energetic, structural, electronic, topological and vibrational characteristics. In general, a gradual convergence towards ...

Checklist for Evaluating SREB-SCORE Learning Objects

Science.gov (United States)

Southern Regional Education Board (SREB), 2007

2007-01-01

This checklist is based on "Evaluation Criteria for SREB-SCORE Learning Objects" and is designed to help schools and colleges determine the quality and effectiveness of learning objects. It is suggested that each learning object be rated to the extent to which it meets the criteria and the SREB-SCORE definition of a learning object. A learning…

Risk scoring for the primary prevention of cardiovascular disease.

Science.gov (United States)

Karmali, Kunal N; Persell, Stephen D; Perel, Pablo; Lloyd-Jones, Donald M; Berendsen, Mark A; Huffman, Mark D

2017-03-14

The current paradigm for cardiovascular disease (CVD) emphasises absolute risk assessment to guide treatment decisions in primary prevention. Although the derivation and validation of multivariable risk assessment tools, or CVD risk scores, have attracted considerable attention, their effect on clinical outcomes is uncertain. To assess the effects of evaluating and providing CVD risk scores in adults without prevalent CVD on cardiovascular outcomes, risk factor levels, preventive medication prescribing, and health behaviours. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (2016, Issue 2), MEDLINE Ovid (1946 to March week 1 2016), Embase (embase.com) (1974 to 15 March 2016), and Conference Proceedings Citation Index-Science (CPCI-S) (1990 to 15 March 2016). We imposed no language restrictions. We searched clinical trial registers in March 2016 and handsearched reference lists of primary studies to identify additional reports. We included randomised and quasi-randomised trials comparing the systematic provision of CVD risk scores by a clinician, healthcare professional, or healthcare system compared with usual care (i.e. no systematic provision of CVD risk scores) in adults without CVD. Three review authors independently selected studies, extracted data, and evaluated study quality. We used the Cochrane 'Risk of bias' tool to assess study limitations. The primary outcomes were: CVD events, change in CVD risk factor levels (total cholesterol, systolic blood pressure, and multivariable CVD risk), and adverse events. Secondary outcomes included: lipid-lowering and antihypertensive medication prescribing in higher-risk people. We calculated risk ratios (RR) for dichotomous data and mean differences (MD) or standardised mean differences (SMD) for continuous data using 95% confidence intervals. We used a fixed-effects model when heterogeneity (I²) was at least 50% and a random-effects model for substantial heterogeneity

Mechanical properties of carbynes investigated by ab initio total-energy calculations

DEFF Research Database (Denmark)

Castelli, Ivano E.; Salvestrini, Paolo; Manini, Nicola

2012-01-01

As sp carbon chains (carbynes) are relatively rigid molecular objects, can we exploit them as construction elements in nanomechanics? To answer this question, we investigate their remarkable mechanical properties by ab initio total-energy simulations. In particular, we evaluate their linear...

Serious Gaming for Test & Evaluation of Clean-Slate (Ab Initio) National Airspace System (NAS) Designs

Science.gov (United States)

Allen, B. Danette; Alexandrov, Natalia

2016-01-01

Incremental approaches to air transportation system development inherit current architectural constraints, which, in turn, place hard bounds on system capacity, efficiency of performance, and complexity. To enable airspace operations of the future, a clean-slate (ab initio) airspace design(s) must be considered. This ab initio National Airspace System (NAS) must be capable of accommodating increased traffic density, a broader diversity of aircraft, and on-demand mobility. System and subsystem designs should scale to accommodate the inevitable demand for airspace services that include large numbers of autonomous Unmanned Aerial Vehicles and a paradigm shift in general aviation (e.g., personal air vehicles) in addition to more traditional aerial vehicles such as commercial jetliners and weather balloons. The complex and adaptive nature of ab initio designs for the future NAS requires new approaches to validation, adding a significant physical experimentation component to analytical and simulation tools. In addition to software modeling and simulation, the ability to exercise system solutions in a flight environment will be an essential aspect of validation. The NASA Langley Research Center (LaRC) Autonomy Incubator seeks to develop a flight simulation infrastructure for ab initio modeling and simulation that assumes no specific NAS architecture and models vehicle-to-vehicle behavior to examine interactions and emergent behaviors among hundreds of intelligent aerial agents exhibiting collaborative, cooperative, coordinative, selfish, and malicious behaviors. The air transportation system of the future will be a complex adaptive system (CAS) characterized by complex and sometimes unpredictable (or unpredicted) behaviors that result from temporal and spatial interactions among large numbers of participants. A CAS not only evolves with a changing environment and adapts to it, it is closely coupled to all systems that constitute the environment. Thus, the ecosystem that

The Use of Quality Control and Data Mining Techniques for Monitoring Scaled Scores: An Overview. Research Report. ETS RR-12-20

Science.gov (United States)

von Davier, Alina A.

2012-01-01

Maintaining comparability of test scores is a major challenge faced by testing programs that have almost continuous administrations. Among the potential problems are scale drift and rapid accumulation of errors. Many standard quality control techniques for testing programs, which can effectively detect and address scale drift for small numbers of…

Nutritional Quality of Breakfast and Physical Activity Independently Predict the Literacy and Numeracy Scores of Children after Adjusting for Socioeconomic Status

Science.gov (United States)

O'Dea, Jennifer A.; Mugridge, Anna C.

2012-01-01

Health-related behaviors [physical activity (PA), nutritional quality of breakfast and sleep]; personal variables (self-esteem, attitudes to PA and gender) and socioeconomic status (SES) (school SES and parental education), were examined in relation to literacy and numeracy scores of 824 grade 3-7 children. Participants completed a questionnaire,…

Quantum calculations of the IR spectrum of liquid water using ab initio and model potential and dipole moment surfaces and comparison with experiment

Energy Technology Data Exchange (ETDEWEB)

Liu, Hanchao; Wang, Yimin; Bowman, Joel M. [Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322 (United States)

2015-05-21

The calculation and characterization of the IR spectrum of liquid water have remained a challenge for theory. In this paper, we address this challenge using a combination of ab initio approaches, namely, a quantum treatment of IR spectrum using the ab initio WHBB water potential energy surface and a refined ab initio dipole moment surface. The quantum treatment is based on the embedded local monomer method, in which the three intramolecular modes of each embedded H{sub 2}O monomer are fully coupled and also coupled singly to each of six intermolecular modes. The new dipole moment surface consists of a previous spectroscopically accurate 1-body dipole moment surface and a newly fitted ab initio intrinsic 2-body dipole moment. A detailed analysis of the new dipole moment surface in terms of the coordinate dependence of the effective atomic charges is done along with tests of it for the water dimer and prism hexamer double-harmonic spectra against direct ab initio calculations. The liquid configurations are taken from previous molecular dynamics calculations of Skinner and co-workers, using the TIP4P plus E3B rigid monomer water potential. The IR spectrum of water at 300 K in the range of 0–4000 cm{sup −1} is calculated and compared with experiment, using the ab initio WHBB potential and new ab initio dipole moment, the q-TIP4P/F potential, which has a fixed-charged description of the dipole moment, and the TTM3-F potential and dipole moment surfaces. The newly calculated ab initio spectrum is in very good agreement with experiment throughout the above spectral range, both in band positions and intensities. This contrasts to results with the other potentials and dipole moments, especially the fixed-charge q-TIP4P/F model, which gives unrealistic intensities. The calculated ab initio spectrum is analyzed by examining the contribution of various transitions to each band.

Quantum calculations of the IR spectrum of liquid water using ab initio and model potential and dipole moment surfaces and comparison with experiment

International Nuclear Information System (INIS)

Liu, Hanchao; Wang, Yimin; Bowman, Joel M.

2015-01-01

The calculation and characterization of the IR spectrum of liquid water have remained a challenge for theory. In this paper, we address this challenge using a combination of ab initio approaches, namely, a quantum treatment of IR spectrum using the ab initio WHBB water potential energy surface and a refined ab initio dipole moment surface. The quantum treatment is based on the embedded local monomer method, in which the three intramolecular modes of each embedded H 2 O monomer are fully coupled and also coupled singly to each of six intermolecular modes. The new dipole moment surface consists of a previous spectroscopically accurate 1-body dipole moment surface and a newly fitted ab initio intrinsic 2-body dipole moment. A detailed analysis of the new dipole moment surface in terms of the coordinate dependence of the effective atomic charges is done along with tests of it for the water dimer and prism hexamer double-harmonic spectra against direct ab initio calculations. The liquid configurations are taken from previous molecular dynamics calculations of Skinner and co-workers, using the TIP4P plus E3B rigid monomer water potential. The IR spectrum of water at 300 K in the range of 0–4000 cm −1 is calculated and compared with experiment, using the ab initio WHBB potential and new ab initio dipole moment, the q-TIP4P/F potential, which has a fixed-charged description of the dipole moment, and the TTM3-F potential and dipole moment surfaces. The newly calculated ab initio spectrum is in very good agreement with experiment throughout the above spectral range, both in band positions and intensities. This contrasts to results with the other potentials and dipole moments, especially the fixed-charge q-TIP4P/F model, which gives unrealistic intensities. The calculated ab initio spectrum is analyzed by examining the contribution of various transitions to each band

Erbium(III) in aqueous solution: an ab initio molecular dynamics study.

Science.gov (United States)

Canaval, Lorenz R; Sakwarathorn, Theerathad; Rode, Bernd M; Messner, Christoph B; Lutz, Oliver M D; Bonn, Günther K

2013-12-05

Structural and dynamical properties of the erbium(III) ion in water have been obtained by means of ab initio quantum mechanical charge field molecular dynamics (QMCF-MD) simulations for the ground state and an excited state. The quality of the simulations has been monitored by recording UV/vis and Raman spectra of dilute solutions of ErCl3 and Er(NO3)3 in water and by comparison with EXAFS data from literature. Slight deviations between these data can be mainly attributed to relativistic effects, which are not sufficiently considered by the methodological framework. In both simulations, a mixture of coordination numbers eight and nine and a ligand exchange on the picosecond range are observed. The strength of the Er-ligand bond is considerably lower than that of trivalent transition metal ions but higher than that for La(III) and Ce(III) in aqueous solution. The main difference between ground state and excited state is the ligand exchange rate of the first shell. The second hydration shell is stable in both cases but with significantly different properties.

Studies Of Urea Geometry By Means Of Ab Initio Methods And Computer Simulations Of Liquids [estudo Da Geometria Da Uréia Por Métodos Ab Initio E Simulaição Computacional De Líquidos

OpenAIRE

Cirino J.J.V.; Bertran C.A.

2002-01-01

A study was carried out on the urea geometries using ab initio calculation and Monte Carlo computational simulation of liquids. The ab initio calculated results showed that urea has a non-planar conformation in the gas phase in which the hydrogen atoms are out of the plane formed by the heavy atoms. Free energies associated to the rotation of the amino groups of urea in water were obtained using the Monte Carlo method in which the thermodynamic perturbation theory is implemented. The magnitud...

Do medical student stress, health, or quality of life foretell step 1 scores? A comparison of students in traditional and revised preclinical curricula.

Science.gov (United States)

Tucker, Phebe; Jeon-Slaughter, Haekyung; Sener, Ugur; Arvidson, Megan; Khalafian, Andrey

2015-01-01

We explored the theory that measures of medical students' well-being and stress from different types of preclinical curricula are linked with performance on standardized assessment. Self-reported stress and quality of life among sophomore medical students having different types of preclinical curricula will vary in their relationships to USMLE Step 1 scores. Voluntary surveys in 2010 and 2011 compared self-reported stress, physical and mental health, and quality of life with Step 1 scores for beginning sophomore students in the final year of a traditional, discipline-based curriculum and the 1st year of a revised, systems-based curriculum with changed grading system. Wilcoxon rank sum tests and Spearman rank correlations were used to analyze data, significant at p students reported worse physical health, subjective feelings, leisure activities, social relationships and morale, and more depressive symptoms and life stress than traditional curriculum students. However, among curriculum-related stressors, few differences emerged; revised curriculum sophomores reported less stress working with real and standardized patients than traditional students. There were no class differences in respondents' Step 1 scores. Among emotional and physical health measures, only feelings of morale correlated negatively with Step 1 performance. Revised curriculum students' Step 1 scores correlated negatively with stress from difficulty of coursework. Although revised curriculum students reported worse quality of life, general stress, and health and less stress from patient interactions than traditional students, few measures were associated with performance differences on Step 1. Moreover, curriculum type did not appear to either hinder or help students' Step 1 performance. To identify and help students at risk for academic problems, future assessments of correlates of Step 1 performance should be repeated after the new curriculum is well established, relating them also to performance

Ab initio calculation of tensile strength in iron

Czech Academy of Sciences Publication Activity Database

Friák, Martin; Šob, Mojmír; Vitek, V.

2003-01-01

Roč. 83, 31-34 (2003), s. 3529-3537 ISSN 1478-6435. [Multiscale Materials Modelling: Working Theory for Industry /1./. London, 17.06.2002-20.06.2002] R&D Projects: GA AV ČR IAA1041302; GA ČR GA202/03/1351; GA MŠk OC 523.90 Institutional research plan: CEZ:AV0Z2041904 Keywords : ab initio calculations * electronic structure * theoretical tensile strength Subject RIV: BM - Solid Matter Physics ; Magnetism

The Protein Digestibility-Corrected Amino Acid Score (PDCAAS) - A concept for describing protein quality in foods and food ingredients: A critical review

NARCIS (Netherlands)

Schaafsma, G.

2005-01-01

Protein Digestibility-Corrected Amino Score (PDCAAS) is discussed. PDCAAS is now widely used as a routine assay for protein quality evaluation, replacing the more traditional biological methods [e.g., measurement of the Protein Efficiency Ratio (PER) in rats]. PDCAAS is based on comparison of the

Hexamethylcyclopentadiene: time-resolved photoelectron spectroscopy and ab initio multiple spawning simulations

DEFF Research Database (Denmark)

Wolf, T. J. A.; Kuhlman, Thomas Scheby; Schalk, O.

2014-01-01

comparing time-resolved photoelectron spectroscopy (TRPES) with ab initio multiple spawning (AIMS) simulations on the MS-MR-CASPT2 level of theory. We disentangle the relationship between two phenomena that dominate the immediate molecular response upon light absorption: a spectrally dependent delay...

Precise Ab-initio prediction of terahertz vibrational modes in crystalline systems

DEFF Research Database (Denmark)

Jepsen, Peter Uhd; Clark, Stewart J.

2007-01-01

We use a combination of experimental THz time-domain spectroscopy and ab-initio density functional perturbative theory to accurately predict the terahertz vibrational spectrum of molecules in the crystalline phase. Our calculations show that distinct vibrational modes found in solid-state materials...

Ab initio molecular dynamics simulation of liquid water by quantum Monte Carlo

International Nuclear Information System (INIS)

Zen, Andrea; Luo, Ye; Mazzola, Guglielmo; Sorella, Sandro; Guidoni, Leonardo

2015-01-01

Although liquid water is ubiquitous in chemical reactions at roots of life and climate on the earth, the prediction of its properties by high-level ab initio molecular dynamics simulations still represents a formidable task for quantum chemistry. In this article, we present a room temperature simulation of liquid water based on the potential energy surface obtained by a many-body wave function through quantum Monte Carlo (QMC) methods. The simulated properties are in good agreement with recent neutron scattering and X-ray experiments, particularly concerning the position of the oxygen-oxygen peak in the radial distribution function, at variance of previous density functional theory attempts. Given the excellent performances of QMC on large scale supercomputers, this work opens new perspectives for predictive and reliable ab initio simulations of complex chemical systems

Raman Spectroscopy and Ab-Initio Model Calculations on Ionic Liquids

DEFF Research Database (Denmark)

Berg, Rolf W.

2007-01-01

spectroscopy and ab-initio molecular orbital calculations. A discussion is given, based mainly on some recent FT-Raman spectroscopic results on the model ionic liquid system of 1-butyl-3-methylimidazolium ([C4mim][X]) salts. The rotational isomerism of the [C4mim]þ cation is described: the presence of anti...

The computation of ionization potentials for second-row elements by ab initio and density functional theory methods

International Nuclear Information System (INIS)

Jursic, B.S.

1996-01-01

Up to four ionization potentials of elements from the second-row of the periodic table were computed using the ab initio (HF, MP2, MP3, MP4, QCISD, GI, G2, and G2MP2) and DFT (B3LY, B3P86, B3PW91, XALPHA, HFS, HFB, BLYP, BP86, BPW91, BVWN, XAPLY, XAP86, XAPW91, XAVWN, SLYR SP86, SPW91 and SVWN) methods. In all of the calculations, the large 6-311++G(3df,3pd) gaussian type of basis set was used. The computed values were compared with the experimental results and suitability of the ab initio and DFF methods were discussed, in regard to reproducing the experimental data. From the computed ionization potentials of the second-row elements, it can be concluded that the HF ab initio computation is not capable of reproducing the experimental results. The computed ionization potentials are too low. However, by using the ab initio methods that include electron correlation, the computed IPs are becoming much closer to the experimental values. In all cases, with the exception of the first ionization potential for oxygen, the G2 computation result produces ionization potentials that are indistinguishable from the experimental results

Independent assessment of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) sample preparation quality: A novel statistical approach for quality scoring.

Science.gov (United States)

Kooijman, Pieter C; Kok, Sander J; Weusten, Jos J A M; Honing, Maarten

2016-05-05

Preparation of samples according to an optimized method is crucial for accurate determination of polymer sample characteristics by Matrix-Assisted Laser Desorption Ionization (MALDI) analysis. Sample preparation conditions such as matrix choice, cationization agent, deposition technique or even the deposition volume should be chosen to suit the sample of interest. Many sample preparation protocols have been developed and employed, yet finding the optimal sample preparation protocol remains a challenge. Because an objective comparison between the results of diverse protocols is not possible, "gut-feeling" or "good enough" is often decisive in the search for an optimum. This implies that sub-optimal protocols are used, leading to a loss of mass spectral information quality. To address this problem a novel analytical strategy based on MALDI imaging and statistical data processing was developed in which eight parameters were formulated to objectively quantify the quality of sample deposition and optimal MALDI matrix composition and finally sum up to an overall quality score of the sample deposition. These parameters can be established in a fully automated way using commercially available mass spectrometry imaging instruments without any hardware adjustments. With the newly developed analytical strategy the highest quality MALDI spots were selected, resulting in more reproducible and more valuable spectra for PEG in a variety of matrices. Moreover, our method enables an objective comparison of sample preparation protocols for any analyte and opens up new fields of investigation by presenting MALDI performance data in a clear and concise way. Copyright © 2016 Elsevier B.V. All rights reserved.

A Bayesian Scoring Technique for Mining Predictive and Non-Spurious Rules

OpenAIRE

Batal, Iyad; Cooper, Gregory; Hauskrecht, Milos

2012-01-01

Rule mining is an important class of data mining methods for discovering interesting patterns in data. The success of a rule mining method heavily depends on the evaluation function that is used to assess the quality of the rules. In this work, we propose a new rule evaluation score - the Predictive and Non-Spurious Rules (PNSR) score. This score relies on Bayesian inference to evaluate the quality of the rules and considers the structure of the rules to filter out spurious rules. We present ...

Ab initio study of H + + H 2 collisions: Elastic/inelastic and charge transfer processes

Science.gov (United States)

Saieswari, A.; Kumar, Sanjay

2007-12-01

An ab initio full configuration interaction study has been undertaken to obtain the global potential energy surfaces for the ground and the first excited electronic state of the H + + H 2 system employing Dunning's cc-pVQZ basis set. Using the ab initio approach the corresponding quasi-diabatic potential energy surfaces and coupling potentials have been obtained. A time-independent quantum mechanical study has been also undertaken for both the inelastic and charge transfer processes at the experimental collision energy Ec.m. = 20.0 eV and the preliminary results show better agreement with the experimental data as compared to the earlier available theoretical studies.

Forging the Basis for Developing Protein-Ligand Interaction Scoring Functions.

Science.gov (United States)

Liu, Zhihai; Su, Minyi; Han, Li; Liu, Jie; Yang, Qifan; Li, Yan; Wang, Renxiao

2017-02-21

In structure-based drug design, scoring functions are widely used for fast evaluation of protein-ligand interactions. They are often applied in combination with molecular docking and de novo design methods. Since the early 1990s, a whole spectrum of protein-ligand interaction scoring functions have been developed. Regardless of their technical difference, scoring functions all need data sets combining protein-ligand complex structures and binding affinity data for parametrization and validation. However, data sets of this kind used to be rather limited in terms of size and quality. On the other hand, standard metrics for evaluating scoring function used to be ambiguous. Scoring functions are often tested in molecular docking or even virtual screening trials, which do not directly reflect the genuine quality of scoring functions. Collectively, these underlying obstacles have impeded the invention of more advanced scoring functions. In this Account, we describe our long-lasting efforts to overcome these obstacles, which involve two related projects. On the first project, we have created the PDBbind database. It is the first database that systematically annotates the protein-ligand complexes in the Protein Data Bank (PDB) with experimental binding data. This database has been updated annually since its first public release in 2004. The latest release (version 2016) provides binding data for 16 179 biomolecular complexes in PDB. Data sets provided by PDBbind have been applied to many computational and statistical studies on protein-ligand interaction and various subjects. In particular, it has become a major data resource for scoring function development. On the second project, we have established the Comparative Assessment of Scoring Functions (CASF) benchmark for scoring function evaluation. Our key idea is to decouple the "scoring" process from the "sampling" process, so scoring functions can be tested in a relatively pure context to reflect their quality. In our

GAUSSIAN 76: an ab initio molecular orbital program

International Nuclear Information System (INIS)

Binkley, J.S.; Whiteside, R.; Hariharan, P.C.; Seeger, R.; Hehre, W.J.; Lathan, W.A.; Newton, M.D.; Ditchfield, R.; Pople, J.A.

Gaussian 76 is a general-purpose computer program for ab initio Hartree-Fock molecular orbital calculations. It can handle basis sets involving s, p and d-type gaussian functions. Certain standard sets (STO-3G, 4-31G, 6-31G*, etc.) are stored internally for easy use. Closed shell (RHF) or unrestricted open shell (UHF) wave functions can be obtained. Facilities are provided for geometry optimization to potential minima and for limited potential surface scans

Ab initio configuration interaction description of excitation energy transfer between closely packed molecules

International Nuclear Information System (INIS)

Fink, R.F.; Pfister, J.; Schneider, A.; Zhao, H.; Engels, B.

2008-01-01

We present new, generally applicable protocols for the computation of the coupling parameter, J, of excitation energy transfer with quantum chemical ab initio methods. The protocols allow to select the degree of approximation and computational demand such that they are applicable for realistic systems and still allow to control the quality of the approach. We demonstrate the capabilities of the different protocols using the CO dimer as a first example. Correlation effects are found to scale J by a factor of about 0.7 which is in good agreement to earlier results obtained for the ethene dimer. The various levels of the protocol allow to assess the influence of ionic configurations and the polarisation within the dimer. Further, the interplay between the Foerster and Dexter contribution to J is investigated. The computations also show error compensation within approximations that are widely used for extended systems as in particular the transition density cube method

Ab initio configuration interaction description of excitation energy transfer between closely packed molecules

Energy Technology Data Exchange (ETDEWEB)

Fink, R.F. [University of Wuerzburg, Institute of Organic Chemistry, Am Hubland, D-97074 Wuerzburg (Germany)], E-mail: reinhold.fink@rub.de; Pfister, J.; Schneider, A.; Zhao, H.; Engels, B. [University of Wuerzburg, Institute of Organic Chemistry, Am Hubland, D-97074 Wuerzburg (Germany)

2008-01-29

We present new, generally applicable protocols for the computation of the coupling parameter, J, of excitation energy transfer with quantum chemical ab initio methods. The protocols allow to select the degree of approximation and computational demand such that they are applicable for realistic systems and still allow to control the quality of the approach. We demonstrate the capabilities of the different protocols using the CO dimer as a first example. Correlation effects are found to scale J by a factor of about 0.7 which is in good agreement to earlier results obtained for the ethene dimer. The various levels of the protocol allow to assess the influence of ionic configurations and the polarisation within the dimer. Further, the interplay between the Foerster and Dexter contribution to J is investigated. The computations also show error compensation within approximations that are widely used for extended systems as in particular the transition density cube method.

A fragment-based approach towards ab-initio treatment of polymeric ...

Indian Academy of Sciences (India)

Reshma S Pingale

2017-06-20

Jun 20, 2017 ... Keywords. π-Conjugated polymer; divide and conquer; ab-initio; fragmentation. PACS Nos 31.15.A−; 36.20. ... cut the parent system into a set of overlapping small fragments and .... some oligomers, we approached the problem by increas- ..... Financial support of DST, Govt. of India, New Delhi, in the form of ...

Ab initio study of the bcc-hcp transformation in iron

Czech Academy of Sciences Publication Activity Database

Friák, Martin; Šob, Mojmír

2008-01-01

Roč. 77, č. 17 (2008), 174117/1-174117/7 ISSN 1098-0121 R&D Projects: GA MŠk OC 147; GA AV ČR IAA1041302 Institutional research plan: CEZ:AV0Z20410507 Keywords : ab initio calculations * phase transformations * iron Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.322, year: 2008

Ab initio and template-based prediction of multi-class distance maps by two-dimensional recursive neural networks

Directory of Open Access Journals (Sweden)

Martin Alberto JM

2009-01-01

Full Text Available Abstract Background Prediction of protein structures from their sequences is still one of the open grand challenges of computational biology. Some approaches to protein structure prediction, especially ab initio ones, rely to some extent on the prediction of residue contact maps. Residue contact map predictions have been assessed at the CASP competition for several years now. Although it has been shown that exact contact maps generally yield correct three-dimensional structures, this is true only at a relatively low resolution (3–4 Å from the native structure. Another known weakness of contact maps is that they are generally predicted ab initio, that is not exploiting information about potential homologues of known structure. Results We introduce a new class of distance restraints for protein structures: multi-class distance maps. We show that Cα trace reconstructions based on 4-class native maps are significantly better than those from residue contact maps. We then build two predictors of 4-class maps based on recursive neural networks: one ab initio, or relying on the sequence and on evolutionary information; one template-based, or in which homology information to known structures is provided as a further input. We show that virtually any level of sequence similarity to structural templates (down to less than 10% yields more accurate 4-class maps than the ab initio predictor. We show that template-based predictions by recursive neural networks are consistently better than the best template and than a number of combinations of the best available templates. We also extract binary residue contact maps at an 8 Å threshold (as per CASP assessment from the 4-class predictors and show that the template-based version is also more accurate than the best template and consistently better than the ab initio one, down to very low levels of sequence identity to structural templates. Furthermore, we test both ab-initio and template-based 8 �

Correcting Grade Deflation Caused by Multiple-Choice Scoring.

Science.gov (United States)

Baranchik, Alvin; Cherkas, Barry

2000-01-01

Presents a study involving three sections of pre-calculus (n=181) at four-year college where partial credit scoring on multiple-choice questions was examined over an entire semester. Indicates that grades determined by partial credit scoring seemed more reflective of both the quantity and quality of student knowledge than grades determined by…

Nuclear quantum effects in ab initio dynamics: Theory and experiments for lithium imide

Science.gov (United States)

Ceriotti, Michele; Miceli, Giacomo; Pietropaolo, Antonino; Colognesi, Daniele; Nale, Angeloclaudio; Catti, Michele; Bernasconi, Marco; Parrinello, Michele

2010-11-01

Owing to their small mass, hydrogen atoms exhibit strong quantum behavior even at room temperature. Including these effects in first-principles calculations is challenging because of the huge computational effort required by conventional techniques. Here we present the first ab initio application of a recently developed stochastic scheme, which allows to approximate nuclear quantum effects inexpensively. The proton momentum distribution of lithium imide, a material of interest for hydrogen storage, was experimentally measured by inelastic neutron-scattering experiments and compared with the outcome of quantum thermostatted ab initio dynamics. We obtain favorable agreement between theory and experiments for this purely quantum-mechanical property, thereby demonstrating that it is possible to improve the modeling of complex hydrogen-containing materials without additional computational effort.

Ab initio theory of charge-carrier conduction in ultrapure organic crystals

NARCIS (Netherlands)

Hannewald, K.; Bobbert, P.A.

2004-01-01

We present an ab initio description of charge-carrier mobilities in organic molecular crystals of high purity. Our approach is based on Holstein's original concept of small-polaron bands but generalized with respect to the inclusion of nonlocal electron-phonon coupling. By means of an explicit

Force fields for silicas and aluminophosphates based on ab initio calculations

NARCIS (Netherlands)

Beest, van B.W.H.; Kramer, G.J.; Santen, van R.A.

1990-01-01

Authors address the problem of finding interat. force fields for silicas from ab initio calcns. on small clusters. The force field cannot be detd. from cluster data alone; incorporation of bulk-system information into the force field remains essential. Bearing this in mind, authors derive a force

Using Ab-Initio Calculations to Appraise Stm-Based - and Kink-Formation Energies

Science.gov (United States)

Feibelman, Peter J.

2001-03-01

Ab-initio total energies can and should be used to test the typically model-dependent results of interpreting STM morphologies. The benefits of such tests are illustrated here by ab-initio energies of step- and kink-formation on Pb and Pt(111) which show that the STM-based values of the kink energies must be revised. On Pt(111), the computed kink-energies for (100)- and (111)-microfacet steps are about 0.25 and 0.18 eV. These results imply a specific ratio of formation energies for the two step types, namely 1.14, in excellent agreement with experiment. If kink-formation actually cost the same energy on the two step types, an inference drawn from scanning probe observations of step wandering,(M. Giesen et al., Surf. Sci. 366, 229(1996).) this ratio ought to be 1. In the case of Pb(111), though computed energies to form (100)- and (111)-microfacet steps agree with measurement, the ab-initio kink-formation energies for the two step types, 41 and 60 meV, are 40-50% below experimental values drawn from STM images.(K. Arenhold et al., Surf. Sci. 424, 271(1999).) The discrepancy results from interpreting the images with a step-stiffness vs. kink-energy relation appropriate to (100) but not (111) surfaces. Good agreement is found when proper account of the trigonal symmetry of Pb(111) is taken in reinterpreting the step-stiffness data.

Electronic properties of liquid Hg-In alloys : Ab-initio molecular dynamics study

International Nuclear Information System (INIS)

Sharma, Nalini; Ahluwalia, P. K.; Thakur, Anil

2016-01-01

Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-In alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Three liquid Hg-In alloys (Hg_1_0In_9_0, Hg_3_0In_7_0_,_. Hg_5_0In_5_0, Hg_7_0In_3_0, and Hg_9_0Pb_1_0) at 299 K are considered. The calculated results for liquid Hg (l-Hg) and lead (l-In) are also drawn. Along with the calculated results of considered five liquid alloys of Hg-In alloy. The results obtained from electronic properties namely total density of state and partial density of states help to find the local arrangement of Hg and In atoms and the presence of liquid state in the considered five alloys.

A Deep Learning Network Approach to ab initio Protein Secondary Structure Prediction.

Science.gov (United States)

Spencer, Matt; Eickholt, Jesse; Jianlin Cheng

2015-01-01

Ab initio protein secondary structure (SS) predictions are utilized to generate tertiary structure predictions, which are increasingly demanded due to the rapid discovery of proteins. Although recent developments have slightly exceeded previous methods of SS prediction, accuracy has stagnated around 80 percent and many wonder if prediction cannot be advanced beyond this ceiling. Disciplines that have traditionally employed neural networks are experimenting with novel deep learning techniques in attempts to stimulate progress. Since neural networks have historically played an important role in SS prediction, we wanted to determine whether deep learning could contribute to the advancement of this field as well. We developed an SS predictor that makes use of the position-specific scoring matrix generated by PSI-BLAST and deep learning network architectures, which we call DNSS. Graphical processing units and CUDA software optimize the deep network architecture and efficiently train the deep networks. Optimal parameters for the training process were determined, and a workflow comprising three separately trained deep networks was constructed in order to make refined predictions. This deep learning network approach was used to predict SS for a fully independent test dataset of 198 proteins, achieving a Q3 accuracy of 80.7 percent and a Sov accuracy of 74.2 percent.

Ab initio calculations and experimental measurement of the deuterium quadrupole coupling constant in Na2PDO3

International Nuclear Information System (INIS)

Trudeau, J.D.; Schwartz, J.L.; Farrar, T.C.

1991-01-01

The deuterium quadrupole coupling constant, χ D , in the PDO 3 2- anion has been measured in solution by NMR spin-lattice (T 1 ) relaxation time measurements and it has been calculated via ab initio methods. The experimental value of 94.7 ± 0.5 kHz is in excellent agreement with the ab initio value of 95.0 kHz. The activation energy for the ion reorientation is 2.23 ± 0.01 kJ mol -1

A simplified score to quantify comorbidity in COPD.

Directory of Open Access Journals (Sweden)

Nirupama Putcha

Full Text Available Comorbidities are common in COPD, but quantifying their burden is difficult. Currently there is a COPD-specific comorbidity index to predict mortality and another to predict general quality of life. We sought to develop and validate a COPD-specific comorbidity score that reflects comorbidity burden on patient-centered outcomes.Using the COPDGene study (GOLD II-IV COPD, we developed comorbidity scores to describe patient-centered outcomes employing three techniques: 1 simple count, 2 weighted score, and 3 weighted score based upon statistical selection procedure. We tested associations, area under the Curve (AUC and calibration statistics to validate scores internally with outcomes of respiratory disease-specific quality of life (St. George's Respiratory Questionnaire, SGRQ, six minute walk distance (6MWD, modified Medical Research Council (mMRC dyspnea score and exacerbation risk, ultimately choosing one score for external validation in SPIROMICS.Associations between comorbidities and all outcomes were comparable across the three scores. All scores added predictive ability to models including age, gender, race, current smoking status, pack-years smoked and FEV1 (p<0.001 for all comparisons. Area under the curve (AUC was similar between all three scores across outcomes: SGRQ (range 0·7624-0·7676, MMRC (0·7590-0·7644, 6MWD (0·7531-0·7560 and exacerbation risk (0·6831-0·6919. Because of similar performance, the comorbidity count was used for external validation. In the SPIROMICS cohort, the comorbidity count performed well to predict SGRQ (AUC 0·7891, MMRC (AUC 0·7611, 6MWD (AUC 0·7086, and exacerbation risk (AUC 0·7341.Quantifying comorbidity provides a more thorough understanding of the risk for patient-centered outcomes in COPD. A comorbidity count performs well to quantify comorbidity in a diverse population with COPD.

Correlation between Family APGAR scores and health-related quality of life of Filipino elderly patients with knee osteoarthritis.

Science.gov (United States)

Lim, Anne T C; Manching, James; Penserga, Ester G

2012-08-01

This study aims to describe the clinical profile of Filipino patients with knee osteoarthritis (OA) and correlate their health-related quality of life (HrQoL) with perceived family support. This is a cross-sectional, analytical study of patients seen at the Philippine General Hospital Arthritis Clinic diagnosed with knee OA using the American College of Rheumatology classification criteria. Questionnaires for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) v.3.1 and Family APGAR (Adaptation, Partnership, Growth, Affection and Resolve) were self-administered. Pearson's correlation, analysis of variance and Bonferroni tests were applied. Ninety patients with 3 : 1 female-to-male ratio, mean age of 70.14 years qualified for the study. Mean body mass index was 23.3. Mean duration of symptoms was 5.9 years. Fifty-three considered their family to be highly functional, 28 moderately dysfunctional and nine severely dysfunctional. Analysis showed that Family APGAR is moderately and inversely correlated with pain (r = -0.3373; P = 0.0002), stiffness (r = -0.3642; P = 0.0004), function (r = -0.3646; P = 0.0004) and total WOMAC scores (r = -0.3880; P = 0.0002). Likewise, there were significant differences of total WOMAC scores in the pain, stiffness and function subscales (P = 0.0076, P = 0.0032, P = 0.0165 and P = 0.0159, respectively) between patients in highly functional and severely dysfunctional families, and between highly and moderately functional families. As Family APGAR scores increased, there was significant decrease in all WOMAC subscales. We described the clinical profile of 90 elderly patients with knee OA and the relationship of HrQoL to Family APGAR scores. This paper concludes that higher Family APGAR scores in this population correlated with better HrQoL. © 2012 The Authors International Journal of Rheumatic Diseases © 2012 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Greater Independence in Activities of Daily Living is Associated with Higher Health-Related Quality of Life Scores in Nursing Home Residents with Dementia

Directory of Open Access Journals (Sweden)

Charice S. Chan

2015-06-01

Full Text Available Health-related quality of life (HRQL for nursing home residents is important, however, the concept of quality of life is broad, encompasses many domains and is difficult to assess in people with dementia. Basic activities of daily living (ADL are measured routinely in nursing homes using the Resident Assessment Instrument-Minimum Data Set Version 2.0 (RAI-MDS and Functional Independence Measure (FIM instrument. We examined the relationship between HRQL and ADL to assess the future possibility of ADL dependency level serving as a surrogate measure of HRQL in residents with dementia. To assess ADL, measures derived from the RAI-MDS and FIM data were gathered for 111 residents at the beginning of our study and at 6-month follow-up. Higher scores for independence in ADL were correlated with higher scores for a disease-specific HRQL measure, the Quality of Life—Alzheimer’s Disease Scale. Preliminary evidence suggests that FIM-assessed ADL is associated with HRQL for these residents. The associations of the dressing and toileting items with HRQL were particularly strong. This finding suggests the importance of ADL function in HRQL. The RAI-MDS ADL scales should be used with caution to evaluate HRQL.

A Bayesian Scoring Technique for Mining Predictive and Non-Spurious Rules.

Science.gov (United States)

Batal, Iyad; Cooper, Gregory; Hauskrecht, Milos

Rule mining is an important class of data mining methods for discovering interesting patterns in data. The success of a rule mining method heavily depends on the evaluation function that is used to assess the quality of the rules. In this work, we propose a new rule evaluation score - the Predictive and Non-Spurious Rules (PNSR) score. This score relies on Bayesian inference to evaluate the quality of the rules and considers the structure of the rules to filter out spurious rules. We present an efficient algorithm for finding rules with high PNSR scores. The experiments demonstrate that our method is able to cover and explain the data with a much smaller rule set than existing methods.

Application of Quaternion in improving the quality of global sequence alignment scores for an ambiguous sequence target in Streptococcus pneumoniae DNA

Science.gov (United States)

Lestari, D.; Bustamam, A.; Novianti, T.; Ardaneswari, G.

2017-07-01

DNA sequence can be defined as a succession of letters, representing the order of nucleotides within DNA, using a permutation of four DNA base codes including adenine (A), guanine (G), cytosine (C), and thymine (T). The precise code of the sequences is determined using DNA sequencing methods and technologies, which have been developed since the 1970s and currently become highly developed, advanced and highly throughput sequencing technologies. So far, DNA sequencing has greatly accelerated biological and medical research and discovery. However, in some cases DNA sequencing could produce any ambiguous and not clear enough sequencing results that make them quite difficult to be determined whether these codes are A, T, G, or C. To solve these problems, in this study we can introduce other representation of DNA codes namely Quaternion Q = (PA, PT, PG, PC), where PA, PT, PG, PC are the probability of A, T, G, C bases that could appear in Q and PA + PT + PG + PC = 1. Furthermore, using Quaternion representations we are able to construct the improved scoring matrix for global sequence alignment processes, by applying a dot product method. Moreover, this scoring matrix produces better and higher quality of the match and mismatch score between two DNA base codes. In implementation, we applied the Needleman-Wunsch global sequence alignment algorithm using Octave, to analyze our target sequence which contains some ambiguous sequence data. The subject sequences are the DNA sequences of Streptococcus pneumoniae families obtained from the Genebank, meanwhile the target DNA sequence are received from our collaborator database. As the results we found the Quaternion representations improve the quality of the sequence alignment score and we can conclude that DNA sequence target has maximum similarity with Streptococcus pneumoniae.

Low quality of life scores in school children with attention deficit-hyperactivity disorder related to anxiety.

Science.gov (United States)

Zambrano-Sánchez, Elizabeth; Martínez-Cortés, José A; del Río-Carlos, Yolanda; Dehesa-Moreno, Minerva; Poblano, Adrián

2012-03-01

Attention deficit hyperactivity disorder (ADHD) is an alteration that begins early in infancy and whose cardinal symptoms are inattention, hyperactivity and impulsivity. There are few studies for specific tests to measure Quality of Life (QoL) in children with ADHD. We evaluated QoL of 120 children from 7-12 years of age with ADHD and of a group of 98 healthy control children. To measure QoL, we utilized the Questionnaire of Quality of Life for Children in Pictures (AutoQuestionnaire Qualité de Vie Enfant Imagé, AUQUEI). We evaluated anxiety in children by the Children´s Manifest Anxiety Scale-Revisited (CMAS-R). We compared results among groups and employed the calculation of correlation between the AUQUEI questionnaire and the CMAS-R scale. The total average of the AUQUEI questionnaire in children with ADHD was 45.2, while in the control group it was 54.3 (pCMAS-R scale. We found significant correlations between AUQUEI questionnaire and CMAS-R scale. The main result was to the disclosure that low QoL scores in ADHD children was anxiety-related.

Ab initio study of hot electrons in GaAs

OpenAIRE

Bernardi, Marco; Vigil-Fowler, Derek; Ong, Chin Shen; Neaton, Jeffrey B.; Louie, Steven G.

2015-01-01

Hot carrier dynamics critically impacts the performance of electronic, optoelectronic, photovoltaic, and plasmonic devices. Hot carriers lose energy over nanometer lengths and picosecond timescales and thus are challenging to study experimentally, whereas calculations of hot carrier dynamics are cumbersome and dominated by empirical approaches. In this work, we present ab initio calculations of hot electrons in gallium arsenide (GaAs) using density functional theory and many-body perturbation...

Functional Movement Screen: Pain versus composite score and injury risk.

Science.gov (United States)

Alemany, Joseph A; Bushman, Timothy T; Grier, Tyson; Anderson, Morgan K; Canham-Chervak, Michelle; North, William J; Jones, Bruce H

2017-11-01

The Functional Movement Screen (FMS™) has been used as a screening tool to determine musculoskeletal injury risk using composite scores based on movement quality and/or pain. However, no direct comparisons between movement quality and pain have been quantified. Retrospective injury data analysis. Male Soldiers (n=2154, 25.0±1.3years; 26.2±.7kg/m 2 ) completed the FMS (scored from 0 points (pain) to 3 points (no pain and perfect movement quality)) with injury data over the following six months. The FMS is seven movements. Injury data were collected six months after FMS completion. Sensitivity, specificity, receiver operator characteristics and positive and negative predictive values were calculated for pain occurrence and low (≤14 points) composite score. Risk, risk ratios (RR) and 95% confidence intervals were calculated for injury risk. Pain was associated with slightly higher injury risk (RR=1.62) than a composite score of ≤14 points (RR=1.58). When comparing injury risk between those who scored a 1, 2 or 3 on each individual movement, no differences were found (except deep squat). However, Soldiers who experienced pain on any movement had a greater injury risk than those who scored 3 points for that movement (pmovements in which pain occurrence increased, so did injury risk (p<0.01). Pain occurrence may be a stronger indicator of injury risk than a low composite score and provides a simpler method of evaluating injury risk compared to the full FMS. Published by Elsevier Ltd.

The sum of friends’ and lovers’ self-control scores predicts relationship quality

NARCIS (Netherlands)

Vohs, K.D.; Finkenauer, C.; Baumeister, R.F.

2011-01-01

What combination of partners' trait self-control levels produces the best relationship outcomes? The authors tested three hypotheses-complementarity (large difference in trait self-control scores), similarity (small difference in self-control scores), and totality (large sum of self-control

The relationship between observer-based toxicity scoring and patient assessed symptom severity after treatment for head and neck cancer. A correlative cross sectional study of the DAHANCA toxicity scoring system and the EORTC quality of life questionnaires

DEFF Research Database (Denmark)

Jensen, Kenneth; Bonde Jensen, Anders; Grau, Cai

2006-01-01

      toxicity scoring systems it has not been formally validated. Conversely,       the EORTC quality of life questionnaire (QLQ) has been validated as a tool       for collecting information about the consequences of disease and treatment       on the well being of cancer patients. The purpose of this study......) completed       EORTC C30, the core questionnaire concerning general symptoms and function       and EORTC H&N35 the head and neck specific questionnaire. The attending       physicians in the follow-up clinic evaluated and recorded DAHANCA toxicity       scores on the same patients. RESULTS: The DAHANCA...... low degree. The       DAHANCA toxicity scores had a low sensitivity (0.48-0.74) in detecting       equivalent subjective complaints from the questionnaires and the       observer-based scoring system severely underestimated patient complaints.       A specific patient group where the DAHANCA score had...

IW-Scoring: an Integrative Weighted Scoring framework for annotating and prioritizing genetic variations in the noncoding genome.

Science.gov (United States)

Wang, Jun; Dayem Ullah, Abu Z; Chelala, Claude

2018-01-30

The vast majority of germline and somatic variations occur in the noncoding part of the genome, only a small fraction of which are believed to be functional. From the tens of thousands of noncoding variations detectable in each genome, identifying and prioritizing driver candidates with putative functional significance is challenging. To address this, we implemented IW-Scoring, a new Integrative Weighted Scoring model to annotate and prioritise functionally relevant noncoding variations. We evaluate 11 scoring methods, and apply an unsupervised spectral approach for subsequent selective integration into two linear weighted functional scoring schemas for known and novel variations. IW-Scoring produces stable high-quality performance as the best predictors for three independent data sets. We demonstrate the robustness of IW-Scoring in identifying recurrent functional mutations in the TERT promoter, as well as disease SNPs in proximity to consensus motifs and with gene regulatory effects. Using follicular lymphoma as a paradigmatic cancer model, we apply IW-Scoring to locate 11 recurrently mutated noncoding regions in 14 follicular lymphoma genomes, and validate 9 of these regions in an extension cohort, including the promoter and enhancer regions of PAX5. Overall, IW-Scoring demonstrates greater versatility in identifying trait- and disease-associated noncoding variants. Scores from IW-Scoring as well as other methods are freely available from http://www.snp-nexus.org/IW-Scoring/. © The Author(s) 2018. Published by Oxford University Press on behalf of Nucleic Acids Research.

Evaluation of a nutrient-rich food index score in the Netherlands

NARCIS (Netherlands)

Sluik, D.; Streppel, M.T.; Lee, van L.; Geelen, A.; Feskens, E.J.M.

2015-01-01

Nutrient-rich food (NRF) index scores are dietary quality indices based on nutrient density. We studied the design aspects involved in the development and validation of NRF index scores, using the Dutch consumption data and guidelines as an example. We evaluated fifteen NRF index scores against the

Ab-initio atomic level stress and role of d-orbitals in CuZr, CuZn and CuY

Science.gov (United States)

Ojha, Madhusudan; Nicholson, Don M.; Egami, Takeshi

2015-03-01

Atomic level stress offers a new tool to characterize materials within the local approximation to density functional theory (DFT). Ab-initio atomic level stresses in B2 structures of CuZr, CuZn and CuY are calculated and results are explained on the basis of d-orbital contributions to Density of States (DOS). The overlap of d-orbital DOS plays an important role in the relative magnitude of atomic level stresses in these structures. The trends in atomic level stresses that we observed in these simple B2 structures are also seen in complex structures such as liquids, glasses and solid solutions. The stresses are however modified by the different coordination and relaxed separation distances in these complex structures. We used the Locally Self-Consistent Multiple Scattering (LSMS) code and Vienna Ab-initio Simulation Package (VASP) for ab-initio calculations.

Feasible and realiable ab initio atomistic modeling for nuclear waste management

Energy Technology Data Exchange (ETDEWEB)

Beridze, George

2016-07-01

The studies in this PhD dissertation focus on finding a computationally feasible ab initio methodology which would make the reliable first principle atomistic modeling of nuclear materials possible. Here we tested the performance of the different DFT functionals and the DFT-based methods that explicitly account for the electronic correlations, such as the DFT+U approach, for prediction of structural and thermochemical properties of lanthanide- and actinide-bearing materials. In the previous studies, the value of the Hubbard U parameter, required by the DFT+U method, was often guessed or empirically derived. We applied and extensively tested the recently developed ab initio methods such as the constrained local density approximation (cLDA) and the constrained random phase approximation (cRPA), to compute the Hubbard U parameter values from first principles, thus making the DFT+U method a real it ab initio parameter free approach. Our successful benchmarking studies of the parameter-free DFT+U method, for prediction of the structures and the reaction enthalpies of actinide- and lanthanide-bearing molecular compounds and solids indicate, that the linear response method (cLDA) provides a very good, and consistent with the cRPA prediction, estimate of the Hubbard U parameter. In particular, we found that the Hubbard U parameter value, which describes the strength of the on-site Coulomb repulsion between f-electrons, depends strongly on the oxidation state of the f-element, its local bonding environment and crystalline structure of the materials, which has never been considered in such detail before. We have shown, that the applied computational approach substantially, if not dramatically, reduces the error of the predicted reaction enthalpies making the accuracy of the prediction comparable with the uncertainty of the computational unfeasible, higher order methods of quantum chemistry, and experiments. The derived methodology resulted in various, already published

Feasible and realiable ab initio atomistic modeling for nuclear waste management

International Nuclear Information System (INIS)

Beridze, George

2016-01-01

The studies in this PhD dissertation focus on finding a computationally feasible ab initio methodology which would make the reliable first principle atomistic modeling of nuclear materials possible. Here we tested the performance of the different DFT functionals and the DFT-based methods that explicitly account for the electronic correlations, such as the DFT+U approach, for prediction of structural and thermochemical properties of lanthanide- and actinide-bearing materials. In the previous studies, the value of the Hubbard U parameter, required by the DFT+U method, was often guessed or empirically derived. We applied and extensively tested the recently developed ab initio methods such as the constrained local density approximation (cLDA) and the constrained random phase approximation (cRPA), to compute the Hubbard U parameter values from first principles, thus making the DFT+U method a real it ab initio parameter free approach. Our successful benchmarking studies of the parameter-free DFT+U method, for prediction of the structures and the reaction enthalpies of actinide- and lanthanide-bearing molecular compounds and solids indicate, that the linear response method (cLDA) provides a very good, and consistent with the cRPA prediction, estimate of the Hubbard U parameter. In particular, we found that the Hubbard U parameter value, which describes the strength of the on-site Coulomb repulsion between f-electrons, depends strongly on the oxidation state of the f-element, its local bonding environment and crystalline structure of the materials, which has never been considered in such detail before. We have shown, that the applied computational approach substantially, if not dramatically, reduces the error of the predicted reaction enthalpies making the accuracy of the prediction comparable with the uncertainty of the computational unfeasible, higher order methods of quantum chemistry, and experiments. The derived methodology resulted in various, already published

Ab initio study of gas phase and water-assisted tautomerization of ...

Indian Academy of Sciences (India)

WINTEC

Water-assisted tautomerization in maleimide and formamide showed that difference in energy barrier reduces to 2⋅83 kcal/mol from 10⋅41 kcal/mol (in gas phase) at B3LYP level, which resulted that maleimide readily undergoes tautomerization in water molecule. Keywords. Ab Initio calculations; maleimide; formamide; ...

Classification and Prioritization of Strategic Plans in Balanced Score Card (BSC Model by Fuzzy Quality Function Deployment and Zero-One Goal Programming (ZOGP

Directory of Open Access Journals (Sweden)

mehdi pourmostafa

2012-02-01

Full Text Available Due to continuous changes in organizational environment, there is no warranty for long term survival in the market. Currently, those organizations can succeed that are agile and able to rapidly respond to environmental requirements. In this research a model has been proposed for applying proper strategies for achieving long term organizational success. The proposed model is an integration of Balanced Score Card (BSC approach, Fuzzy Quality Function Development (FQFD and Zero-One Goal Programming (ZOGP. In fact by BSC, appropriate strategic plans can be designed and prioritized by FQFD. Then, based on multiple objectives and existing problem constraints, feasible strategic plans are identified by ZOGP. Findings imply that decision making techniques can be well utilized in designing BSC through a structured methodology make improvement in all aspects and have a positive influence on organization's performance in long term .   Keywords : B alanced Score Card , Fuzzy Quality Function Development, Zero-One Goal Programming, Strategic plans

Coupling of ab initio density functional theory and molecular dynamics for the multiscale modeling of carbon nanotubes

International Nuclear Information System (INIS)

Ng, T Y; Yeak, S H; Liew, K M

2008-01-01

A multiscale technique is developed that couples empirical molecular dynamics (MD) and ab initio density functional theory (DFT). An overlap handshaking region between the empirical MD and ab initio DFT regions is formulated and the interaction forces between the carbon atoms are calculated based on the second-generation reactive empirical bond order potential, the long-range Lennard-Jones potential as well as the quantum-mechanical DFT derived forces. A density of point algorithm is also developed to track all interatomic distances in the system, and to activate and establish the DFT and handshaking regions. Through parallel computing, this multiscale method is used here to study the dynamic behavior of single-walled carbon nanotubes (SWCNTs) under asymmetrical axial compression. The detection of sideways buckling due to the asymmetrical axial compression is reported and discussed. It is noted from this study on SWCNTs that the MD results may be stiffer compared to those with electron density considerations, i.e. first-principle ab initio methods

Methods and statistics for combining motif match scores.

Science.gov (United States)

Bailey, T L; Gribskov, M

1998-01-01

Position-specific scoring matrices are useful for representing and searching for protein sequence motifs. A sequence family can often be described by a group of one or more motifs, and an effective search must combine the scores for matching a sequence to each of the motifs in the group. We describe three methods for combining match scores and estimating the statistical significance of the combined scores and evaluate the search quality (classification accuracy) and the accuracy of the estimate of statistical significance of each. The three methods are: 1) sum of scores, 2) sum of reduced variates, 3) product of score p-values. We show that method 3) is superior to the other two methods in both regards, and that combining motif scores indeed gives better search accuracy. The MAST sequence homology search algorithm utilizing the product of p-values scoring method is available for interactive use and downloading at URL http:/(/)www.sdsc.edu/MEME.

Thermal transport in nanocrystalline Si and SiGe by ab initio based Monte Carlo simulation.

Science.gov (United States)

Yang, Lina; Minnich, Austin J

2017-03-14

Nanocrystalline thermoelectric materials based on Si have long been of interest because Si is earth-abundant, inexpensive, and non-toxic. However, a poor understanding of phonon grain boundary scattering and its effect on thermal conductivity has impeded efforts to improve the thermoelectric figure of merit. Here, we report an ab-initio based computational study of thermal transport in nanocrystalline Si-based materials using a variance-reduced Monte Carlo method with the full phonon dispersion and intrinsic lifetimes from first-principles as input. By fitting the transmission profile of grain boundaries, we obtain excellent agreement with experimental thermal conductivity of nanocrystalline Si [Wang et al. Nano Letters 11, 2206 (2011)]. Based on these calculations, we examine phonon transport in nanocrystalline SiGe alloys with ab-initio electron-phonon scattering rates. Our calculations show that low energy phonons still transport substantial amounts of heat in these materials, despite scattering by electron-phonon interactions, due to the high transmission of phonons at grain boundaries, and thus improvements in ZT are still possible by disrupting these modes. This work demonstrates the important insights into phonon transport that can be obtained using ab-initio based Monte Carlo simulations in complex nanostructured materials.

Combination of scoring schemes for protein docking

Directory of Open Access Journals (Sweden)

Schomburg Dietmar

2007-08-01

Full Text Available Abstract Background Docking algorithms are developed to predict in which orientation two proteins are likely to bind under natural conditions. The currently used methods usually consist of a sampling step followed by a scoring step. We developed a weighted geometric correlation based on optimised atom specific weighting factors and combined them with our previously published amino acid specific scoring and with a comprehensive SVM-based scoring function. Results The scoring with the atom specific weighting factors yields better results than the amino acid specific scoring. In combination with SVM-based scoring functions the percentage of complexes for which a near native structure can be predicted within the top 100 ranks increased from 14% with the geometric scoring to 54% with the combination of all scoring functions. Especially for the enzyme-inhibitor complexes the results of the ranking are excellent. For half of these complexes a near-native structure can be predicted within the first 10 proposed structures and for more than 86% of all enzyme-inhibitor complexes within the first 50 predicted structures. Conclusion We were able to develop a combination of different scoring schemes which considers a series of previously described and some new scoring criteria yielding a remarkable improvement of prediction quality.

Ab initio theories of electric transport in solid systems with reduced dimensions

International Nuclear Information System (INIS)

Weinberger, Peter

2003-01-01

Ab initio theories of electric transport in solid systems with reduced dimensions, i.e., systems that at best are characterized by two-dimensional translational invariance, are reviewed in terms of a fully relativistic description of the Kubo-Greenwood equation. As the use of this equation requires concepts such as collinearity and non-collinearity in order to properly define resistivities or resistances corresponding to particular magnetic configurations, respective consequences of the (local) density functional theory are recalled in quite a detailed manner. Furthermore, since theoretical descriptions of solid systems with reduced dimensions require quantum mechanical methods different from bulk systems (three-dimensional periodicity), the so-called Screened Korringa-Kohn-Rostoker (SKKR-) method for layered systems is introduced together with a matching coherent potential approximation (inhomogeneous CPA). The applications shown are mainly meant to illustrate various aspects of electric transport in solid systems with reduced dimensions and comprise not only current-in-plane (CIP) experiments, but also current perpendicular to the planes of atoms geometries, consequences of tunneling, and finite nanostructures at or on metallic substrates. In order to give a more complete view of available ab initio methods also a non-relativistic approach based on the Tight Binding Linear Combination of muffin tin orbitals (TB-LMTO-) method and the so-called Kubo-Landauer equation in terms of transmission and reflection matrices is presented. A compilation of references with respect to ab-initio type approaches not explicitly discussed in here finally concludes the discussion of electric properties in solid systems with reduced dimensions

An Efficient Method for Electron-Atom Scattering Using Ab-initio Calculations

Energy Technology Data Exchange (ETDEWEB)

Xu, Yuan; Yang, Yonggang; Xiao, Liantuan; Jia, Suotang [Shanxi University, Taiyuan (China)

2017-02-15

We present an efficient method based on ab-initio calculations to investigate electron-atom scatterings. Those calculations profit from methods implemented in standard quantum chemistry programs. The new approach is applied to electron-helium scattering. The results are compared with experimental and other theoretical references to demonstrate the efficiency of our method.

Ab initio study of electron-ion structure factors in binary liquids with different types of chemical bonding

International Nuclear Information System (INIS)

Klevets, Ivan; Bryk, Taras

2014-01-01

Electron-ion structure factors, calculated in ab initio molecular dynamics simulations, are reported for several binary liquids with different kinds of chemical bonding: metallic liquid alloy Bi–Pb, molten salt RbF, and liquid water. We derive analytical expressions for the long-wavelength asymptotes of the partial electron-ion structure factors of binary systems and show that the analytical results are in good agreement with the ab initio simulation data. The long-wavelength behaviour of the total charge structure factors for the three binary liquids is discussed

Identifying Stereoisomers by ab-initio Calculation of Secondary Isotope Shifts on NMR Chemical Shieldings

Directory of Open Access Journals (Sweden)

Karl-Heinz Böhm

2014-04-01

Full Text Available We present ab-initio calculations of secondary isotope effects on NMR chemical shieldings. The change of the NMR chemical shift of a certain nucleus that is observed if another nucleus is replaced by a different isotope can be calculated by computing vibrational corrections on the NMR parameters using electronic structure methods. We demonstrate that the accuracy of the computational results is sufficient to even distinguish different conformers. For this purpose, benchmark calculations for fluoro(2-2Hethane in gauche and antiperiplanar conformation are carried out at the HF, MP2 and CCSD(T level of theory using basis sets ranging from double- to quadruple-zeta quality. The methodology is applied to the secondary isotope shifts for 2-fluoronorbornane in order to resolve an ambiguity in the literature on the assignment of endo- and exo-2-fluoronorbornanes with deuterium substituents in endo-3 and exo-3 positions, also yielding insight into mechanistic details of the corresponding synthesis.

Identifying stereoisomers by ab-initio calculation of secondary isotope shifts on NMR chemical shieldings.

Science.gov (United States)

Böhm, Karl-Heinz; Banert, Klaus; Auer, Alexander A

2014-04-23

We present ab-initio calculations of secondary isotope effects on NMR chemical shieldings. The change of the NMR chemical shift of a certain nucleus that is observed if another nucleus is replaced by a different isotope can be calculated by computing vibrational corrections on the NMR parameters using electronic structure methods. We demonstrate that the accuracy of the computational results is sufficient to even distinguish different conformers. For this purpose, benchmark calculations for fluoro(2-2H)ethane in gauche and antiperiplanar conformation are carried out at the HF, MP2 and CCSD(T) level of theory using basis sets ranging from double- to quadruple-zeta quality. The methodology is applied to the secondary isotope shifts for 2-fluoronorbornane in order to resolve an ambiguity in the literature on the assignment of endo- and exo-2-fluoronorbornanes with deuterium substituents in endo-3 and exo-3 positions, also yielding insight into mechanistic details of the corresponding synthesis.

Ab initio molecular dynamics simulation of hydrogen fluoride at several thermodynamic states

DEFF Research Database (Denmark)

Kreitmeir, M.; Bertagnolli, H.; Mortensen, Jens Jørgen

2003-01-01

Liquid hydrogen fluoride is a simple but interesting system for studies of the influence of hydrogen bonds on physical properties. We have performed ab initio molecular dynamics simulations of HF at several thermodynamic states, where we examine the microscopic structure of the liquid as well...

Ab initio Calculations of Charge Symmetry Breaking in the A=4 Hypernuclei

Czech Academy of Sciences Publication Activity Database

Gazda, Daniel; Gal, A.

2016-01-01

Roč. 116, č. 12 (2016), s. 122501 ISSN 0031-9007 R&D Projects: GA ČR(CZ) GA15-04301S Institutional support: RVO:61389005 Keywords : ab initio * shell model * four-body calculations Subject RIV: BE - Theoretical Physics Impact factor: 8.462, year: 2016

Ab initio calculation atomics ground state wave function for interactions Ion- Atom

International Nuclear Information System (INIS)

Shojaee, F.; Bolori zadeh, M. A.

2007-01-01

Ab initio calculation atomics ground state wave function for interactions Ion- Atom Atomic wave function expressed in a Slater - type basis obtained within Roothaan- Hartree - Fock for the ground state of the atoms He through B. The total energy is given for each atom.

Structural investigation of water-acetonitrile mixtures: An ab initio, molecular dynamics and X-ray diffraction study

International Nuclear Information System (INIS)

Bako, Imre; Megyes, Tuende; Palinkas, Gabor

2005-01-01

In this work, we present a study on water-acetonitrile (AN) mixtures by molecular dynamics ab initio and X-ray diffraction techniques. Comparison of the experimental total G(r) functions of the mixtures with the results of molecular dynamics simulation shows an overall good agreement. The properties of hydrogen bonded clusters (water clusters, and water-AN clusters) in these mixtures have been determined. Two different types of AN-water dimers were identified by ab initio quantum chemical calculation. One of these structures proved to be a true H-bonded dimer and the other a dipole bound dimer

An ab-initio study of mechanical, dynamical and electronic properties of MgEu intermetallic

Science.gov (United States)

Kumar, S. Ramesh; Jaiganesh, G.; Jayalakshmi, V.

2018-04-01

The theoretical investigation on the mechanical, dynamical and electronic properties of MgEu in CsCl-type structure has been carried out through the ab-initio calculations within the framework of the density functional theory and the density functional perturbation theory. For the purpose, Vienna Ab initio Simulation Package and Phonopy packages were used. Our calculated ground-state properties of MgEu are in good agreement with other available results. Our computed elastic constants and phonon spectrum results suggest that MgEu is mechanically and dynamically stable up to 5 GPa. The thermodynamic quantities as a function of temperatures are also reported and discussed. The band structure, density of states and charge density also calculated to understand the electronic properties of MgEu.

DeepQA: improving the estimation of single protein model quality with deep belief networks.

Science.gov (United States)

Cao, Renzhi; Bhattacharya, Debswapna; Hou, Jie; Cheng, Jianlin

2016-12-05

Protein quality assessment (QA) useful for ranking and selecting protein models has long been viewed as one of the major challenges for protein tertiary structure prediction. Especially, estimating the quality of a single protein model, which is important for selecting a few good models out of a large model pool consisting of mostly low-quality models, is still a largely unsolved problem. We introduce a novel single-model quality assessment method DeepQA based on deep belief network that utilizes a number of selected features describing the quality of a model from different perspectives, such as energy, physio-chemical characteristics, and structural information. The deep belief network is trained on several large datasets consisting of models from the Critical Assessment of Protein Structure Prediction (CASP) experiments, several publicly available datasets, and models generated by our in-house ab initio method. Our experiments demonstrate that deep belief network has better performance compared to Support Vector Machines and Neural Networks on the protein model quality assessment problem, and our method DeepQA achieves the state-of-the-art performance on CASP11 dataset. It also outperformed two well-established methods in selecting good outlier models from a large set of models of mostly low quality generated by ab initio modeling methods. DeepQA is a useful deep learning tool for protein single model quality assessment and protein structure prediction. The source code, executable, document and training/test datasets of DeepQA for Linux is freely available to non-commercial users at http://cactus.rnet.missouri.edu/DeepQA/ .

Ab-initio calculations of electric field gradient in Ru compounds and ...

Indian Academy of Sciences (India)

S N Mishra

2017-07-11

Jul 11, 2017 ... with calculated electric field gradient (EFG) for a large number of Ru-based compounds. The ab-initio ... zz assumed to stem from geometric arrangement of ... tant nuclear probes for the measurements of quadrupole ... with the unit cell including the nucleus and no restriction is put on ..... The effect of on-site ...

Room temperature linelists for CO2 asymmetric isotopologues with ab initio computed intensities

Science.gov (United States)

Zak, Emil J.; Tennyson, Jonathan; Polyansky, Oleg L.; Lodi, Lorenzo; Zobov, Nikolay F.; Tashkun, Sergei A.; Perevalov, Valery I.

2017-12-01

The present paper reports room temperature line lists for six asymmetric isotopologues of carbon dioxide: 16O12C18O (628), 16O12C17O (627), 16O13C18O (638),16O13C17O (637), 17O12C18O (728) and 17O13C18O (738), covering the range 0-8000 cm-1. Variational rotation-vibration wavefunctions and energy levels are computed using the DVR3D software suite and a high quality semi-empirical potential energy surface (PES), followed by computation of intensities using an ab initio dipole moment surface (DMS). A theoretical procedure for quantifying sensitivity of line intensities to minor distortions of the PES/DMS renders our theoretical model as critically evaluated. Several recent high quality measurements and theoretical approaches are discussed to provide a benchmark of our results against the most accurate available data. Indeed, the thesis of transferability of accuracy among different isotopologues with the use of mass-independent PES is supported by several examples. Thereby, we conclude that the majority of line intensities for strong bands are predicted with sub-percent accuracy. Accurate line positions are generated using an effective Hamiltonian, constructed from the latest experiments. This study completes the list of relevant isotopologues of carbon dioxide; these line lists are available to remote sensing studies and inclusion in databases.

TiAl doping by vanadium: ab initio study

International Nuclear Information System (INIS)

Smirnova, E.A.; Isaev, Eh.I.; Vekilov, Yu.Kh.

2004-01-01

Tetragonality degree in TiAl and vanadium doping effect on it were studied using the methods of calculation based on approximation of coherent potential and ab initio pseudopotentials. It is shown that vanadium substitution for Ti sublattice atoms entails increase in tetragonality degree but with substitution of the atoms in aluminium sublattice the tetragonality of the TiAl:V alloy decreases and at the content of vanadium about 8 at. % the lattice becomes actually cubical. In its turn, it may result in increase in TiAl ductility, the alloy being brittle at low temperatures [ru

Ab initio, mean field theory and series expansions calculations study of electronic and magnetic properties of antiferromagnetic MnSe alloys

Energy Technology Data Exchange (ETDEWEB)

Masrour, R., E-mail: rachidmasrour@hotmail.com [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, BP. 63, 46000 Safi (Morocco); LMPHE (URAC 12), Faculty of Science, Mohammed V-Agdal University, Rabat (Morocco); Hlil, E.K. [Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9 (France); Hamedoun, M. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Benyoussef, A. [LMPHE (URAC 12), Faculty of Science, Mohammed V-Agdal University, Rabat (Morocco); Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Hassan II Academy of Science and Technology, Rabat (Morocco); Mounkachi, O.; El Moussaoui, H. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco)

2014-06-01

Self-consistent ab initio calculations, based on DFT (Density Functional Theory) approach and using FLAPW (Full potential Linear Augmented Plane Wave) method, are performed to investigate both electronic and magnetic properties of the MnSe lattice. Polarized spin and spin–orbit coupling are included in calculations within the framework of the antiferromagnetic state between two adjacent Mn lattices. Magnetic moments considered to lie along (001) axes are computed. Obtained data from ab initio calculations are used as input for the high temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The zero-field high temperature static susceptibility series of the spin −4.28 nearest-neighbor Ising model on face centered cubic (fcc) and lattices is thoroughly analyzed by means of a power series coherent anomaly method (CAM). The exchange interaction between the magnetic atoms and the Néel temperature are deduced using the mean filed and HTSEs theories. - Highlights: • Ab initio calculations are used to investigate both electronic and magnetic properties of the MnSe alloys. • Obtained data from ab initio calculations are used as input for the HTSEs. • The Néel temperature is obtained for MnSe alloys.

Quantum wavepacket ab initio molecular dynamics: an approach for computing dynamically averaged vibrational spectra including critical nuclear quantum effects.

Science.gov (United States)

Sumner, Isaiah; Iyengar, Srinivasan S

2007-10-18

We have introduced a computational methodology to study vibrational spectroscopy in clusters inclusive of critical nuclear quantum effects. This approach is based on the recently developed quantum wavepacket ab initio molecular dynamics method that combines quantum wavepacket dynamics with ab initio molecular dynamics. The computational efficiency of the dynamical procedure is drastically improved (by several orders of magnitude) through the utilization of wavelet-based techniques combined with the previously introduced time-dependent deterministic sampling procedure measure to achieve stable, picosecond length, quantum-classical dynamics of electrons and nuclei in clusters. The dynamical information is employed to construct a novel cumulative flux/velocity correlation function, where the wavepacket flux from the quantized particle is combined with classical nuclear velocities to obtain the vibrational density of states. The approach is demonstrated by computing the vibrational density of states of [Cl-H-Cl]-, inclusive of critical quantum nuclear effects, and our results are in good agreement with experiment. A general hierarchical procedure is also provided, based on electronic structure harmonic frequencies, classical ab initio molecular dynamics, computation of nuclear quantum-mechanical eigenstates, and employing quantum wavepacket ab initio dynamics to understand vibrational spectroscopy in hydrogen-bonded clusters that display large degrees of anharmonicities.

The impact of disability, fatigue and sleep quality on the quality of life in multiple sclerosis

Directory of Open Access Journals (Sweden)

Ghaem Haleh

2008-01-01

Full Text Available Background: Only few papers have investigated the impact of multiple sclerosis (MS, especially MS-related fatigue and the impact of the quality of sleep on the quality of life (QoL in MS patients. Objective: The objective of this study was to measure the quality of life in MS patients and the impact of disability, fatigue and sleep quality, using statistical modeling. Materials and Methods: A cross-sectional study was conducted and data was collected from 141 MS patients, who were referred to the Mottahari Clinic, Shiraz, Iran, in 2005. Data on health-related quality of life (MSQoL-54, fatigue severity scale (FSS, and Pittsburgh sleep quality Index (PSQI were obtained in the case of all the patients. Epidemiology data concerning MS type, MS functional system score, expanded disability status scale (EDSS etc. were also provided by a qualified neurologist. Spearman a coefficient, Mann-Whitney U test, and linear regression model were used to analyze the data. Results : The mean ±SD age of 141 MS patients was 32.6±9.6 year. Thirty five (24.8% of them were male and the others were female. Eighty two (58.1% of the patients had EDSS score of ≤ 2, 36 (25.5% between 2.5 and 4.5, and 23 (16.3% ≥ 5. As per PSQI scores, two (1.4% of the patients had good sleep, 16 (11.3% had moderate sleep and 123 (87.2% had poor sleep. There was a significant high positive correlation between the quality of mental and physical health composite scores (r = 0.791, P < 0.001. There was a significant negative correlation between the quality of physical score and age (r = -0.88, P < 0.001, fatigue score (r = -0.640, P < 0.001, EDSS score (r = -0.476, P < 0.001 and PSQI (sleep quality r = -0.514, P < 0.000. Linear regression analysis showed that PSQI score, EDSS, and fatigue score were predictors in the model between the quality of physical score and covariates ( P < 0.001. Linear regression model showed that fatigue score and PSQI were predictors in the model between the

Sleep quality and quality of life in female shift-working nurses.

Science.gov (United States)

Shao, Ming-Fen; Chou, Yu-Ching; Yeh, Mei-Yu; Tzeng, Wen-Chii

2010-07-01

This paper is a report of a study of the factors that influence sleep quality and quality of life among shift-working nurses and the relationship between their sleep quality and quality of life. Although shift-working nurses strive to adapt their life schedules to shift rotations, they tend to suffer from severe sleep disturbances and increased rates of cancer, cardiovascular diseases, digestive disease and irregular menstrual cycles. Poor sleep is also associated with medical errors and occupational injuries. A cross-sectional study was conducted in 2008 with a convenience sample of 435 female nurses from five regional hospitals in Taiwan. Data were collected on sleep quality and quality of life using the Pittsburgh Sleep Quality Index and World Health Organization Quality of Life Instrument-BREF Taiwan version respectively. Data were analysed using descriptive statistics, independent t-tests, analysis of variance and Pearson correlations. The majority of female shift workers (57%) had global sleep-quality scores > or = 5, indicating poor sleep and all mean scores in four domains of the quality-of-life measure were statistically significantly lower than those of females in Taiwan's general population. Scores for poor sleep quality and quality of life were related to premenstrual dysphoria, occupational injury, illness and medication use. In addition, the associations between scores on the sleep-quality and quality-of-life scales were statistically significantly inversely correlated. Advice should be included in both undergraduate programmes and continuing education to help nurses to recognize and improve their own sleep quality and life quality managers should create a supportive environment to encourage shift-working nurses to engage in healthy behaviours.

Does the emergency surgery score accurately predict outcomes in emergent laparotomies?

Science.gov (United States)

Peponis, Thomas; Bohnen, Jordan D; Sangji, Naveen F; Nandan, Anirudh R; Han, Kelsey; Lee, Jarone; Yeh, D Dante; de Moya, Marc A; Velmahos, George C; Chang, David C; Kaafarani, Haytham M A

2017-08-01

The emergency surgery score is a mortality-risk calculator for emergency general operation patients. We sought to examine whether the emergency surgery score predicts 30-day morbidity and mortality in a high-risk group of patients undergoing emergent laparotomy. Using the 2011-2012 American College of Surgeons National Surgical Quality Improvement Program database, we identified all patients who underwent emergent laparotomy using (1) the American College of Surgeons National Surgical Quality Improvement Program definition of "emergent," and (2) all Current Procedural Terminology codes denoting a laparotomy, excluding aortic aneurysm rupture. Multivariable logistic regression analyses were performed to measure the correlation (c-statistic) between the emergency surgery score and (1) 30-day mortality, and (2) 30-day morbidity after emergent laparotomy. As sensitivity analyses, the correlation between the emergency surgery score and 30-day mortality was also evaluated in prespecified subgroups based on Current Procedural Terminology codes. A total of 26,410 emergent laparotomy patients were included. Thirty-day mortality and morbidity were 10.2% and 43.8%, respectively. The emergency surgery score correlated well with mortality (c-statistic = 0.84); scores of 1, 11, and 22 correlated with mortalities of 0.4%, 39%, and 100%, respectively. Similarly, the emergency surgery score correlated well with morbidity (c-statistic = 0.74); scores of 0, 7, and 11 correlated with complication rates of 13%, 58%, and 79%, respectively. The morbidity rates plateaued for scores higher than 11. Sensitivity analyses demonstrated that the emergency surgery score effectively predicts mortality in patients undergoing emergent (1) splenic, (2) gastroduodenal, (3) intestinal, (4) hepatobiliary, or (5) incarcerated ventral hernia operation. The emergency surgery score accurately predicts outcomes in all types of emergent laparotomy patients and may prove valuable as a bedside decision

Airline Quality Rating 2001

OpenAIRE

Bowen, Brent D.; Headley, Dean E.

2001-01-01

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, Airline Quality Rating 2001, reflects monthly Airline Quality Rating scores for 2000. AQR scores for the calendar year 2000 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2001 is a summary of month-by-month quality ra...

Ab Initio theory of the Gilbert damping in random ferromagnetic alloys

Czech Academy of Sciences Publication Activity Database

Drchal, Václav; Turek, I.; Kudrnovský, Josef

2017-01-01

Roč. 30, č. 6 (2017), s. 1669-1672 ISSN 1557-1939 R&D Projects: GA ČR GA15-13436S Institutional support: RVO:68378271 Keywords : Gilbert damping * ferromagnetic alloys * ab initio * nonlocal torques Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.180, year: 2016

Ab initio electronic stopping power in materials

International Nuclear Information System (INIS)

Shukri, Abdullah-Atef

2015-01-01

The average energy loss of an ion per unit path length when it is moving through the matter is named the stopping power. The knowledge of the stopping power is essential for a variety of contemporary applications which depend on the transport of ions in matter, especially ion beam analysis techniques and ion implantation. Most noticeably, the use of proton or heavier ion beams in radiotherapy requires the knowledge of the stopping power. Whereas experimental data are readily available for elemental solids, the data are much more scarce for compounds. The linear response dielectric formalism has been widely used in the past to study the electronic stopping power. In particular, the famous pioneering calculations due to Lindhard evaluate the electronic stopping power of a free electron gas. In this thesis, we develop a fully ab initio scheme based on linear response time-dependent density functional theory to predict the impact parameter averaged quantity named the random electronic stopping power (RESP) of materials without any empirical fitting. The purpose is to be capable of predicting the outcome of experiments without any knowledge of target material besides its crystallographic structure. Our developments have been done within the open source ab initio code named ABINIT, where two approximations are now available: the Random-Phase Approximation (RPA) and the Adiabatic Local Density Approximation (ALDA). Furthermore, a new method named 'extrapolation scheme' have been introduced to overcome the stringent convergence issues we have encountered. These convergence issues have prevented the previous studies in literature from offering a direct comparison to experiment. First of all, we demonstrate the importance of describing the realistic ab initio electronic structure by comparing with the historical Lindhard stopping power evaluation. Whereas the Lindhard stopping power provides a first order description that captures the general features of the

Score distribution of the scoliosis research society health-related quality of life in different subgroups of adolescent subjects unaffected by scoliosis in China.

Science.gov (United States)

Wu, Weifei; Du, Yuanli; Liang, Jie; Chen, Ying; Tan, Xiaoyi; Xiang, Xuanping; Wang, Wanhong; Ru, Neng

2014-02-01

A comparative study. The aims of this study were to: (1) evaluate Scoliosis Research Society (SRS)-22 questionnaire performance in normal adolescents without scoliosis to establish a normative baseline useful for evaluating the discriminate validity of the SRS-22 in primary adolescent scoliosis; and (2) investigate impact of age and sex on SRS-22 in an adolescent population unaffected by scoliosis. The SRS-22 questionnaire is widely used to measure health-related quality of life of patients with spinal disease including scoliosis and lumbar spondylolisthesis. However, normal data, which are very important, when comparing patients and nonpatients, are few, little, and there are few studies about factors that may affect SRS questionnaire performance. The adolescent population was from 14 schools located in 7 provinces. A total of 2008 adolescents (961 females, 1026 males, 21 unknown; mean age, 14.3 yr; range, 11-20) completed the simplified Chinese version of SRS-22 questionnaire and demographic questions. Surveys were stratified into 8 age-sex groups for analysis: male/female; 12 to 13.4, 13.5 to 14.9, 15 to 15.9, and more than 16 years of age. Post hoc testing and the Tukey least significant difference were used to compare differences between any 2 of the 4 age groups. Self-image scores in males were higher than those in females (P < 0.01). Pain domain scores were significantly higher in males than those in females in the 13.5- to 14.9-year-old subgroup, whereas other subgroups showed no obvious differences. The function domain scores in males who were aged 15 to 15.9 years and those older than 16 years were significantly higher than those in females (P < 0.001). There were no statistically significant differences in mental health domain scores among age-sex subgroups, with the exception of the 13.5- to 14.9-year-old group. This is the first study to characterize the sex and age influence on the SRS-22 scores in normal population. Age and sex have an important

Ab initio calculations on hydrogen storage in porous carbons

International Nuclear Information System (INIS)

Maresca, O.; Marinelli, F.; Pellenq, R.J.M.; Duclaux, L.; Azais, Ph.; Conard, J.

2005-01-01

We have investigated through ab initio computations the possible ways to achieve efficient hydrogen storage on carbons. Firstly, we have considered how the curvature of a carbon surface could affect the chemisorption of atomic H 0 Secondly, we show that electron donor elements such as Li and K, used as dopants for the carbon substrate, strongly enhance the physi-sorption energy of H 2 , allowing in principle its storage in this type of material at room temperature under mild conditions of pressure. (authors)

The Veterans Affairs Cardiac Risk Score: Recalibrating the Atherosclerotic Cardiovascular Disease Score for Applied Use.

Science.gov (United States)

Sussman, Jeremy B; Wiitala, Wyndy L; Zawistowski, Matthew; Hofer, Timothy P; Bentley, Douglas; Hayward, Rodney A

2017-09-01

Accurately estimating cardiovascular risk is fundamental to good decision-making in cardiovascular disease (CVD) prevention, but risk scores developed in one population often perform poorly in dissimilar populations. We sought to examine whether a large integrated health system can use their electronic health data to better predict individual patients' risk of developing CVD. We created a cohort using all patients ages 45-80 who used Department of Veterans Affairs (VA) ambulatory care services in 2006 with no history of CVD, heart failure, or loop diuretics. Our outcome variable was new-onset CVD in 2007-2011. We then developed a series of recalibrated scores, including a fully refit "VA Risk Score-CVD (VARS-CVD)." We tested the different scores using standard measures of prediction quality. For the 1,512,092 patients in the study, the Atherosclerotic cardiovascular disease risk score had similar discrimination as the VARS-CVD (c-statistic of 0.66 in men and 0.73 in women), but the Atherosclerotic cardiovascular disease model had poor calibration, predicting 63% more events than observed. Calibration was excellent in the fully recalibrated VARS-CVD tool, but simpler techniques tested proved less reliable. We found that local electronic health record data can be used to estimate CVD better than an established risk score based on research populations. Recalibration improved estimates dramatically, and the type of recalibration was important. Such tools can also easily be integrated into health system's electronic health record and can be more readily updated.

Molecular structure determination of cyclooctane by Ab Initio and electron diffraction methods in the gas phase; Determinacao da estrutura molecular do ciclooctano por metodos Ab Initio e difracao de eletrons na fase gasosa

Energy Technology Data Exchange (ETDEWEB)

Almeida, Wagner B. de [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Quimica

2000-10-01

The determination of the molecular structure of molecules is of fundamental importance in chemistry. X-rays and electron diffraction methods constitute in important tools for the elucidation of the molecular structure of systems in the solid state and gas phase, respectively. The use of quantum mechanical molecular orbital ab initio methods offer an alternative for conformational analysis studies. Comparison between theoretical results and those obtained experimentally in the gas phase can make a significant contribution for an unambiguous determination of the geometrical parameters. In this article the determination for an unambiguous determination of the geometrical parameters. In this article the determination of the molecular structure of the cyclooctane molecule by electron diffraction in the gas phase an initio calculations will be addressed, providing an example of a comparative analysis of theoretical and experimental predictions. (author)

Computational prediction of muon stopping sites using ab initio random structure searching (AIRSS)

Science.gov (United States)

Liborio, Leandro; Sturniolo, Simone; Jochym, Dominik

2018-04-01

The stopping site of the muon in a muon-spin relaxation experiment is in general unknown. There are some techniques that can be used to guess the muon stopping site, but they often rely on approximations and are not generally applicable to all cases. In this work, we propose a purely theoretical method to predict muon stopping sites in crystalline materials from first principles. The method is based on a combination of ab initio calculations, random structure searching, and machine learning, and it has successfully predicted the MuT and MuBC stopping sites of muonium in Si, diamond, and Ge, as well as the muonium stopping site in LiF, without any recourse to experimental results. The method makes use of Soprano, a Python library developed to aid ab initio computational crystallography, that was publicly released and contains all the software tools necessary to reproduce our analysis.

Ab initio theoretical calculations of the electronic excitation energies of small water clusters.

Science.gov (United States)

Tachikawa, Hiroto; Yabushita, Akihiro; Kawasaki, Masahiro

2011-12-14

A direct ab initio molecular dynamics method has been applied to a water monomer and water clusters (H(2)O)(n) (n = 1-3) to elucidate the effects of zero-point energy (ZPE) vibration on the absorption spectra of water clusters. Static ab initio calculations without ZPE showed that the first electronic transitions of (H(2)O)(n), (1)B(1)←(1)A(1), are blue-shifted as a function of cluster size (n): 7.38 eV (n = 1), 7.58 eV (n = 2) and 8.01 eV (n = 3). The inclusion of the ZPE vibration strongly affects the excitation energies of a water dimer, and a long red-tail appears in the range of 6.42-6.90 eV due to the structural flexibility of a water dimer. The ultraviolet photodissociation of water clusters and water ice surfaces is relevant to these results.

Bridging a gap between continuum-QCD and ab initio predictions of hadron observables

Energy Technology Data Exchange (ETDEWEB)

Binosi, Daniele [European Centre for Theoretical Studies in Nuclear Physics and Related Areas - ECT* and Fondazione Bruno Kessler, Villa Tambosi, Strada delle Tabarelle 286, I-38123 Villazzano (Italy); Chang, Lei [CSSM, School of Chemistry and Physics, University of Adelaide, Adelaide, SA 5005 (Australia); Papavassiliou, Joannis [Department of Theoretical Physics and IFIC, University of Valencia and CSIC, E-46100, Valencia (Spain); Roberts, Craig D., E-mail: cdroberts@anl.gov [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

2015-03-06

Within contemporary hadron physics there are two common methods for determining the momentum-dependence of the interaction between quarks: the top-down approach, which works toward an ab initio computation of the interaction via direct analysis of the gauge-sector gap equations; and the bottom-up scheme, which aims to infer the interaction by fitting data within a well-defined truncation of those equations in the matter sector that are relevant to bound-state properties. We unite these two approaches by demonstrating that the renormalisation-group-invariant running-interaction predicted by contemporary analyses of QCD's gauge sector coincides with that required in order to describe ground-state hadron observables using a nonperturbative truncation of QCD's Dyson–Schwinger equations in the matter sector. This bridges a gap that had lain between nonperturbative continuum-QCD and the ab initio prediction of bound-state properties.

Airline Quality Rating 2003

OpenAIRE

Bowen, Brent D.; Headley, Dean E.

2003-01-01

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2003, reflects monthly Airline Quality Rating scores for 2002. AQR scores for the calendar year 2002 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2003 is a summary of month-by-month qualit...

Airline Quality Rating 2013

OpenAIRE

Bowen, Brent D.; Headley, Dean E.

2013-01-01

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method for assessing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2013, reflects monthly Airline Quality Rating scores for calendar year 2012. AQR scores for 2013 are based on 15 elements in four major areas that focus on airline performance aspects important to air travel consumers over the calendar year of 2012. The Airline Quality...

A scored human protein-protein interaction network to catalyze genomic interpretation

DEFF Research Database (Denmark)

Li, Taibo; Wernersson, Rasmus; Hansen, Rasmus B

2017-01-01

Genome-scale human protein-protein interaction networks are critical to understanding cell biology and interpreting genomic data, but challenging to produce experimentally. Through data integration and quality control, we provide a scored human protein-protein interaction network (InWeb_InBioMap,......Genome-scale human protein-protein interaction networks are critical to understanding cell biology and interpreting genomic data, but challenging to produce experimentally. Through data integration and quality control, we provide a scored human protein-protein interaction network (In...

Higher Mediterranean Diet Quality Scores and Lower Body Mass Index Are Associated with a Less-Oxidized Plasma Glutathione and Cysteine Redox Status in Adults.

Science.gov (United States)

Bettermann, Erika L; Hartman, Terryl J; Easley, Kirk A; Ferranti, Erin P; Jones, Dean P; Quyyumi, Arshed A; Vaccarino, Viola; Ziegler, Thomas R; Alvarez, Jessica A

2018-02-01

Both systemic redox status and diet quality are associated with risk outcomes in chronic disease. It is not known, however, the extent to which diet quality influences plasma thiol/disulfide redox status. The purpose of this study was to investigate the influence of diet, as measured by diet quality scores and other dietary factors, on systemic thiol/disulfide redox status. We performed a cross-sectional study of 685 working men and women (ages ≥18 y) in Atlanta, GA. Diet was assessed by 3 diet quality scores: the Alternative Healthy Eating Index (AHEI), Dietary Approaches to Stop Hypertension (DASH), and the Mediterranean Diet Score (MDS). We measured concentrations of plasma glutathione (GSH), cysteine, their associated oxidized forms [glutathione disulfide (GSSG) and cystine (CySS), respectively], and their redox potentials (EhGSSG and EhCySS) to determine thiol/disulfide redox status. Linear regression modeling was performed to assess relations between diet and plasma redox after adjustment for age, body mass index (BMI), sex, race, and history of chronic disease. MDS was positively associated with plasma GSH (β = 0.02; 95% CI: 0.003, 0.03) and total GSH (GSH + GSSG) (β = 0.02; 95% CI: 0.003, 0.03), and inversely associated with the CySS:GSH ratio (β = -0.02; 95% CI: -0.04, -0.004). There were significant independent associations between individual MDS components (dairy, vegetables, fish, and monounsaturated fat intake) and varying plasma redox indexes (P indexes and other diet factors of interest were not significantly correlated with plasma thiol and disulfide redox measures. Adherence to the Mediterranean diet was significantly associated with a favorable plasma thiol/disulfide redox profile, independent of BMI, in a generally healthy working adult population. Although longitudinal studies are warranted, these findings contribute to the feasibility of targeting a Mediterranean diet to improve plasma redox status.

The ANKLe Score: An Audit of Otolaryngology Emergency Clinic Record Keeping

Science.gov (United States)

Dexter, Sara C; Hayashi, Daichi; Tysome, James R

2008-01-01

INTRODUCTION Accurate and legible medical records are essential to good quality patient care. Guidelines from The Royal College of Surgeons of England (RCSE) state the content required to form a complete medical record, but do not address legibility. An audit of otolaryngology emergency clinic record keeping was performed using a new scoring system. PATIENTS AND METHODS The Adjusted Note Keeping and Legibility (ANKLe) score was developed as an objective and quantitative method to assess both the content and legibility of case notes, incorporating the RCSE guidelines. Twenty consecutive otolaryngology emergency clinic case notes from each of 7 senior house officers were audited against standards for legibility and content using the ANKLe score. A proforma was introduced to improve documentation and handwriting advice was given. A further set of 140 notes (20 notes for each of the 7 doctors) was audited in the same way to provide feedback. RESULTS The introduction of a proforma and advice on handwriting significantly increased the quality of case note entries in terms of content, legibility and overall ANKLe score. CONCLUSIONS Accurate note keeping can be improved by the use of a proforma. The legibility of handwriting can be improved using simple advice. The ANKLe score is an objective assessment tool of the overall quality of medical note documentation which can be adapted for use in other specialties. PMID:18430339

Explicit polarization (X-Pol) potential using ab initio molecular orbital theory and density functional theory.

Science.gov (United States)

Song, Lingchun; Han, Jaebeom; Lin, Yen-lin; Xie, Wangshen; Gao, Jiali

2009-10-29

The explicit polarization (X-Pol) method has been examined using ab initio molecular orbital theory and density functional theory. The X-Pol potential was designed to provide a novel theoretical framework for developing next-generation force fields for biomolecular simulations. Importantly, the X-Pol potential is a general method, which can be employed with any level of electronic structure theory. The present study illustrates the implementation of the X-Pol method using ab initio Hartree-Fock theory and hybrid density functional theory. The computational results are illustrated by considering a set of bimolecular complexes of small organic molecules and ions with water. The computed interaction energies and hydrogen bond geometries are in good accord with CCSD(T) calculations and B3LYP/aug-cc-pVDZ optimizations.

A Initio Theoretical Studies of Surfaces of Semiconductors

Science.gov (United States)

Wang, Jing

1993-01-01

The first semiconductor which we study with these techniques is the archetypal elemental semiconductor, silicon. We present the first extensive study of point defects on Si(100). We identify the principal defects and two primary mechanisms responsible for their dominance: the need to eliminate dangling bonds on the surface and the need to compensate the strain induced by topological effects. Furthermore, we present evidence that the presence of point defects on the Si(100) surface is not intrinsic to the ground state of the surface as a stress relieving mechanism but rather is due merely to thermal fluctuations. We address materials issues associated with the identification of the lowest energy surfaces of GaAs and the determination of the geometric structure of a GaAs crystallite growing freely in three dimensions. The fracture energies associated with (110), (100) and (111) interface planes are calculated and a Wulff construction indicates that an ideal stoichiometric GaAs crystal should be terminated with (110) surfaces. We investigate the more complex issues that arise on surfaces when aspects of these two semiconductors are mixed. We investigate the problem of growing GaAs on the Si(100) surface and demonstrate how and why the most fundamental properties of the resulting bulk GaAs material, such as its crystalline orientation, may depend sensitively on the interplay between growth conditions such as temperature and the properties of the Si surface. For stepped Si(100) -As, we show that the growth of As directly on top of the Si surface produces a metastable state, while the replacement of the original top Si layer leads to a lower energy configuration, with the rearrangement of the surface driven by the relaxation of stress by surface steps. Finally, we study delta -doping, where one attempts to grow a single layer of Si on a GaAs surface before continuing with the growth of bulk GaAs. We shall employ a slightly different modality of the ab initio approach. We

Using ab initio 'data' to accurately determine the fourth density virial coefficient of helium

International Nuclear Information System (INIS)

Moldover, Michael R.; McLinden, Mark O.

2010-01-01

We combine accurate ab initio calculations of the second and third density virial coefficients, B(T) and C(T), of 4 He with measurements of its (p-ρ-T) behavior to determine the fourth density virial coefficient D(T). The measurements were made with a two-sinker, magnetic-suspension densimeter at pressures up to 38 MPa. The measurements on isotherms from T = 223 K to T = 323 K were previously published; new measurements from T = 323 K to T = 500 K are presented here. On each isotherm, a regression of the virial expansion was constrained to the ab initio values of B(T) and C(T); the regression determined D(T) as well as two apparatus-dependent parameters that compensated for systematic errors in the measurements. The percentage uncertainties of D(T) ranged from 2.6% at T = 223 K to 9.5% at T = 400 K to 24.7% at T = 500 K, where these uncertainties are expanded uncertainties with coverage factor of k = 2 corresponding to a 95% confidence interval. These uncertainties are 1/6th of the uncertainty obtained without the ab initio values of B(T) and C(T). The apparatus-dependent parameters can be used to calibrate the densimeter, and this will reduce the uncertainty of other measurements made with this two-sinker densimeter. The new values of D(T) will find applications in accurate gas metrology, such as a primary pressure standard based on the refractive index of helium.

Ab Initio Predictions of Hexagonal Zr(B,C,N) Polymorphs for Coherent Interface Design

Energy Technology Data Exchange (ETDEWEB)

Hu, Chongze [Univ. of Minnesota-Twin Cities, Minneapolis, MN (United States); Huang, Jingsong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sumpter, Bobby G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meletis, Efstathios [Univ. of Texas at Arlington, Arlington, TX (United States); Dumitrica, Traian [Univ. of Minnesota-Twin Cities, Minneapolis, MN (United States)

2017-10-27

Density functional theory calculations are used to explore hexagonal (HX) NiAs-like polymorphs of Zr(B,C,N) and compare with corresponding Zr(B,C,N) Hagg-like face-centered cubic rocksalt (B1) phases. While all predicted compounds are mechanically stable according to the Born-Huang criteria, only HX Zr(C,N) are found dynamically stable from ab initio molecular dynamics simulations and lattice dynamics calculations. HX ZrN emerges as a candidate structure with ground state energy, elastic constants, and extrinsic mechanical parameters comparable with those of B1 ZrN. Ab initio band structure and semi-classical Boltzmann transport calculations predict a metallic character and a monotonic increase in electrical conductivity with the number of valence electrons. Electronic structure calculations indicate that the HX phases gain their stability and mechanical attributes by Zr d- non-metal p hybridization and by broadening of Zr d bands. Furthermore, it is shown that the HX ZrN phase provides a low-energy coherent interface model for connecting B1 ZrN domains, with significant energetic advantage over an atomistic interface model derived from high resolution transmission electron microscopy images. The ab initio characterizations provided herein should aid the experimental identification of non-Hagg-like hard phases. Furthermore, the results can also enrich the variety of crystalline phases potentially available for designing coherent interfaces in superhard nanostructured materials and in materials with multilayer characteristics.

Ab Initio Studies of Shock-Induced Chemical Reactions of Inter-Metallics

Science.gov (United States)

Zaharieva, Roussislava; Hanagud, Sathya

2009-06-01

Shock-induced and shock assisted chemical reactions of intermetallic mixtures are studied by many researchers, using both experimental and theoretical techniques. The theoretical studies are primarily at continuum scales. The model frameworks include mixture theories and meso-scale models of grains of porous mixtures. The reaction models vary from equilibrium thermodynamic model to several non-equilibrium thermodynamic models. The shock-effects are primarily studied using appropriate conservation equations and numerical techniques to integrate the equations. All these models require material constants from experiments and estimates of transition states. Thus, the objective of this paper is to present studies based on ab initio techniques. The ab inito studies, to date, use ab inito molecular dynamics. This paper presents a study that uses shock pressures, and associated temperatures as starting variables. Then intermetallic mixtures are modeled as slabs. The required shock stresses are created by straining the lattice. Then, ab initio binding energy calculations are used to examine the stability of the reactions. Binding energies are obtained for different strain components super imposed on uniform compression and finite temperatures. Then, vibrational frequencies and nudge elastic band techniques are used to study reactivity and transition states. Examples include Ni and Al.

Ab Initio Values of the Thermophysical Properties of Helium as Standards

Science.gov (United States)

Hurly, John J.; Moldover, Michael R.

2000-01-01

Recent quantum mechanical calculations of the interaction energy of pairs of helium atoms are accurate and some include reliable estimates of their uncertainty. We combined these ab initio results with earlier published results to obtain a helium-helium interatomic potential that includes relativistic retardation effects over all ranges of interaction. From this potential, we calculated the thermophysical properties of helium, i.e., the second virial coefficients, the dilute-gas viscosities, and the dilute-gas thermal conductivities of 3He, 4He, and their equimolar mixture from 1 K to 104 K. We also calculated the diffusion and thermal diffusion coefficients of mixtures of 3He and 4He. For the pure fluids, the uncertainties of the calculated values are dominated by the uncertainties of the potential; for the mixtures, the uncertainties of the transport properties also include contributions from approximations in the transport theory. In all cases, the uncertainties are smaller than the corresponding experimental uncertainties; therefore, we recommend the ab initio results be used as standards for calibrating instruments relying on these thermophysical properties. We present the calculated thermophysical properties in easy-to-use tabular form. PMID:27551630

Equations of state of heavy metals: ab initio approaches; Equations d'etat des metaux lourds: approches ab initio

Energy Technology Data Exchange (ETDEWEB)

Bernard, S.; Jollet, F.; Jomard, G.; Siberchicot, B.; Torrent, M.; Zerah, G.; Amadon, B.; Bouchet, J.; Richard, N.; Robert, G. [CEA Bruyeres-le-Chatel, 91 (France)

2005-07-01

The determination of equations of states of heavy metals through ab initio calculation, i.e. without any adjustable parameter, allows to access to pressure and temperature thermodynamic conditions sometimes inaccessible to experiment. To perform such calculations, density functional theory (DFT) is a good starting point: when electronic densities are homogeneous enough, the local density approximation (LDA) remarkably accounts for thermodynamic properties of heavy metals, such as tantalum, or the light actinides, as well for static properties - equilibrium volume, elastic constants - as for dynamical quantities like phonon spectra. For heavier elements, like neptunium or plutonium, relativistic effects and strong electronic interactions must be taken into account, which requires more sophisticated theoretical approaches. (authors)

Low quality of life scores in school children with attention deficit-hyperactivity disorder related to anxiety

Directory of Open Access Journals (Sweden)

Elizabeth Zambrano-Sánchez

2012-03-01

Full Text Available OBJECTIVE: Attention deficit hyperactivity disorder (ADHD is an alteration that begins early in infancy and whose cardinal symptoms are inattention, hyperactivity and impulsivity. There are few studies for specific tests to measure Quality of Life (QoL in children with ADHD. METHODS: We evaluated QoL of 120 children from 7-12 years of age with ADHD and of a group of 98 healthy control children. To measure QoL, we utilized the Questionnaire of Quality of Life for Children in Pictures (AutoQuestionnaire Qualité de Vie Enfant Imagé, AUQUEI. We evaluated anxiety in children by the Children´s Manifest Anxiety Scale-Revisited (CMAS-R. We compared results among groups and employed the calculation of correlation between the AUQUEI questionnaire and the CMAS-R scale. RESULTS: The total average of the AUQUEI questionnaire in children with ADHD was 45.2, while in the control group it was 54.3 (p<0.05. We also observed significant differences between the control group and groups of children with ADHD in the CMAS-R scale. We found significant correlations between AUQUEI questionnaire and CMAS-R scale. CONCLUSION: The main result was to the disclosure that low QoL scores in ADHD children was anxiety-related.

Limitations of Ab Initio Predictions of Peptide Binding to MHC Class II Molecules

DEFF Research Database (Denmark)

Zhang, Hao; Lund, Ole; Nielsen, Morten

2010-01-01

potentials derived from the analysis of known protein structures; energetic evaluation of different peptide snapshots in a molecular dynamics simulation; and direct analysis of contacts made in known 3D structures of peptide:MHC complexes. These methods are ab initio in that they require structural data...

Ab initio and work function and surface energy anisotropy of LaB6

NARCIS (Netherlands)

Uijttewaal, M. A.; de Wijs, G. A.; de Groot, R. A.

2006-01-01

Lanthanum hexaboride is one of the cathode materials most used in high-power electronics technology, but the many experimental results do not provide a consistent picture of the surface properties. Therefore, we report the first ab initio calculations of the work functions and surface energies of

Ab initio Based Modeling of Radiation Effects in Multi-Component Alloys: Final Scientific/Technical Report

Energy Technology Data Exchange (ETDEWEB)

Dane Morgan

2010-06-10

The project began March 13, 2006, allocated for three years, and received a one year extension from March 13, 2009 to March 12, 2010. It has now completed 48 of 48 total months. The project was focused on using ab initio methods to gain insights into radiation induced segregation (RIS) in Ni-Fe-Cr alloys. The project had the following key accomplishments • Development of a large database of ab initio energetics that can be used by many researchers in the future for increased understanding of this system. For example, we have the first calculations showing a dramatic stabilization effect of Cr-Cr interstitial dumbbells in Ni. • Prediction of both vacancy and interstitial diffusion constants for Ni-Cr and Ni-Fe for dilute Cr and Fe. This work included generalization of widely used multifrequency models to make use of ab initio derived energetics and thermodynamics. • Prediction of qualitative trends of RIS from vacancy and interstitial mechanisms, suggesting the two types of defect fluxes drive Cr RIS in opposite directions. • Detailed kinetic Monte Carlo modeling of diffusion by vacancy mechanism in Ni-Cr as a function of Cr concentration. The results demonstrate that Cr content can have a significant effect on RIS. • Development of a quantitative RIS transport model, including models for thermodynamic factors and boundary conditions.

Ground state analytical ab initio intermolecular potential for the Cl2-water system

International Nuclear Information System (INIS)

Hormain, Laureline; Monnerville, Maurice; Toubin, Céline; Duflot, Denis; Pouilly, Brigitte; Briquez, Stéphane; Bernal-Uruchurtu, Margarita I.; Hernández-Lamoneda, Ramón

2015-01-01

The chlorine/water interface is of crucial importance in the context of atmospheric chemistry. Modeling the structure and dynamics at this interface requires an accurate description of the interaction potential energy surfaces. We propose here an analytical intermolecular potential that reproduces the interaction between the Cl 2 molecule and a water molecule. Our functional form is fitted to a set of high level ab initio data using the coupled-cluster single double (triple)/aug-cc-p-VTZ level of electronic structure theory for the Cl 2 − H 2 O complex. The potential fitted to reproduce the three minima structures of 1:1 complex is validated by the comparison of ab initio results of Cl 2 interacting with an increasing number of water molecules. Finally, the model potential is used to study the physisorption of Cl 2 on a perfectly ordered hexagonal ice slab. The calculated adsorption energy, in the range 0.27 eV, shows a good agreement with previous experimental results

"Score the Core" Web-based pathologist training tool improves the accuracy of breast cancer IHC4 scoring.

Science.gov (United States)

Engelberg, Jesse A; Retallack, Hanna; Balassanian, Ronald; Dowsett, Mitchell; Zabaglo, Lila; Ram, Arishneel A; Apple, Sophia K; Bishop, John W; Borowsky, Alexander D; Carpenter, Philip M; Chen, Yunn-Yi; Datnow, Brian; Elson, Sarah; Hasteh, Farnaz; Lin, Fritz; Moatamed, Neda A; Zhang, Yanhong; Cardiff, Robert D

2015-11-01

Hormone receptor status is an integral component of decision-making in breast cancer management. IHC4 score is an algorithm that combines hormone receptor, HER2, and Ki-67 status to provide a semiquantitative prognostic score for breast cancer. High accuracy and low interobserver variance are important to ensure the score is accurately calculated; however, few previous efforts have been made to measure or decrease interobserver variance. We developed a Web-based training tool, called "Score the Core" (STC) using tissue microarrays to train pathologists to visually score estrogen receptor (using the 300-point H score), progesterone receptor (percent positive), and Ki-67 (percent positive). STC used a reference score calculated from a reproducible manual counting method. Pathologists in the Athena Breast Health Network and pathology residents at associated institutions completed the exercise. By using STC, pathologists improved their estrogen receptor H score and progesterone receptor and Ki-67 proportion assessment and demonstrated a good correlation between pathologist and reference scores. In addition, we collected information about pathologist performance that allowed us to compare individual pathologists and measures of agreement. Pathologists' assessment of the proportion of positive cells was closer to the reference than their assessment of the relative intensity of positive cells. Careful training and assessment should be used to ensure the accuracy of breast biomarkers. This is particularly important as breast cancer diagnostics become increasingly quantitative and reproducible. Our training tool is a novel approach for pathologist training that can serve as an important component of ongoing quality assessment and can improve the accuracy of breast cancer prognostic biomarkers. Copyright © 2015 Elsevier Inc. All rights reserved.

Ab initio thermodynamic model for magnesium carbonates and hydrates.

Science.gov (United States)

Chaka, Anne M; Felmy, Andrew R

2014-09-04

An ab initio thermodynamic framework for predicting properties of hydrated magnesium carbonate minerals has been developed using density-functional theory linked to macroscopic thermodynamics through the experimental chemical potentials for MgO, water, and CO2. Including semiempirical dispersion via the Grimme method and small corrections to the generalized gradient approximation of Perdew, Burke, and Ernzerhof for the heat of formation yields a model with quantitative agreement for the benchmark minerals brucite, magnesite, nesquehonite, and hydromagnesite. The model shows how small differences in experimental conditions determine whether nesquehonite, hydromagnesite, or magnesite is the result of laboratory synthesis from carbonation of brucite, and what transformations are expected to occur on geological time scales. Because of the reliance on parameter-free first-principles methods, the model is reliably extensible to experimental conditions not readily accessible to experiment and to any mineral composition for which the structure is known or can be hypothesized, including structures containing defects, substitutions, or transitional structures during solid state transformations induced by temperature changes or processes such as water, CO2, or O2 diffusion. Demonstrated applications of the ab initio thermodynamic framework include an independent means to evaluate differences in thermodynamic data for lansfordite, predicting the properties of Mg analogues of Ca-based hydrated carbonates monohydrocalcite and ikaite, which have not been observed in nature, and an estimation of the thermodynamics of barringtonite from the stoichiometry and a single experimental observation.

Longitudinal beta regression models for analyzing health-related quality of life scores over time

Directory of Open Access Journals (Sweden)

Hunger Matthias

2012-09-01

Full Text Available Abstract Background Health-related quality of life (HRQL has become an increasingly important outcome parameter in clinical trials and epidemiological research. HRQL scores are typically bounded at both ends of the scale and often highly skewed. Several regression techniques have been proposed to model such data in cross-sectional studies, however, methods applicable in longitudinal research are less well researched. This study examined the use of beta regression models for analyzing longitudinal HRQL data using two empirical examples with distributional features typically encountered in practice. Methods We used SF-6D utility data from a German older age cohort study and stroke-specific HRQL data from a randomized controlled trial. We described the conceptual differences between mixed and marginal beta regression models and compared both models to the commonly used linear mixed model in terms of overall fit and predictive accuracy. Results At any measurement time, the beta distribution fitted the SF-6D utility data and stroke-specific HRQL data better than the normal distribution. The mixed beta model showed better likelihood-based fit statistics than the linear mixed model and respected the boundedness of the outcome variable. However, it tended to underestimate the true mean at the upper part of the distribution. Adjusted group means from marginal beta model and linear mixed model were nearly identical but differences could be observed with respect to standard errors. Conclusions Understanding the conceptual differences between mixed and marginal beta regression models is important for their proper use in the analysis of longitudinal HRQL data. Beta regression fits the typical distribution of HRQL data better than linear mixed models, however, if focus is on estimating group mean scores rather than making individual predictions, the two methods might not differ substantially.

Ab initio R-matrix/Multi-channel Quantum Defect Theory applied to Molecular Core Excitation and Ionization

International Nuclear Information System (INIS)

Hiyama, M.; Kosugi, N.

2004-01-01

Full text: Ab initio R-matrix/MQDT approach, which is a combination of ab initio R-matrix techniques and the multi channel quantum defect theory (MQDT), has recently been developed by one of the present authors (MH) and Child, to successfully obtain the potential energy curves of Rydberg states converging to not only the lowest but also the higher ionized states. This approach is also applied to estimate the valence state interaction with Rydberg and continuum (ionization) channels. Very recently we have made an original ab initio polyatomic R-matrix/MQDT program package, GSCF4R based on Gaussian type basis functions for the bound and continuum states, to extensively study molecular excitation and ionization in the X-ray region as well as in the VUV region. We are going to report the results for core excitation and ionization of diatomic molecules such as NO and O 2 to show that the R-matrix/MQDT method is indispensable to describe the core-to-Rydberg states with the higher quantum number and the continuum states. These results lead us to the conclusion that the close-coupling approximation augmented with the correlation term within the R-matrix/MQDT formalism is powerful to calculate the Rydberg-valence mixing and the interchannel coupling between several core-ionized states

How reliable are Functional Movement Screening scores? A systematic review of rater reliability.

Science.gov (United States)

Moran, Robert W; Schneiders, Anthony G; Major, Katherine M; Sullivan, S John

2016-05-01

Several physical assessment protocols to identify intrinsic risk factors for injury aetiology related to movement quality have been described. The Functional Movement Screen (FMS) is a standardised, field-expedient test battery intended to assess movement quality and has been used clinically in preparticipation screening and in sports injury research. To critically appraise and summarise research investigating the reliability of scores obtained using the FMS battery. Systematic literature review. Systematic search of Google Scholar, Scopus (including ScienceDirect and PubMed), EBSCO (including Academic Search Complete, AMED, CINAHL, Health Source: Nursing/Academic Edition), MEDLINE and SPORTDiscus. Studies meeting eligibility criteria were assessed by 2 reviewers for risk of bias using the Quality Appraisal of Reliability Studies checklist. Overall quality of evidence was determined using van Tulder's levels of evidence approach. 12 studies were appraised. Overall, there was a 'moderate' level of evidence in favour of 'acceptable' (intraclass correlation coefficient ≥0.6) inter-rater and intra-rater reliability for composite scores derived from live scoring. For inter-rater reliability of composite scores derived from video recordings there was 'conflicting' evidence, and 'limited' evidence for intra-rater reliability. For inter-rater reliability based on live scoring of individual subtests there was 'moderate' evidence of 'acceptable' reliability (κ≥0.4) for 4 subtests (Deep Squat, Shoulder Mobility, Active Straight-leg Raise, Trunk Stability Push-up) and 'conflicting' evidence for the remaining 3 (Hurdle Step, In-line Lunge, Rotary Stability). This review found 'moderate' evidence that raters can achieve acceptable levels of inter-rater and intra-rater reliability of composite FMS scores when using live ratings. Overall, there were few high-quality studies, and the quality of several studies was impacted by poor study reporting particularly in relation to

All-electron ab initio investigations of the electronic states of the NiC molecule

DEFF Research Database (Denmark)

Shim, Irene; Gingerich, Karl. A.

1999-01-01

The low-lying electronic states of NiC are investigated by all-electron ab initio multi-configuration self-consistent-field (CASSCF) calculations including relativistic corrections. The electronic structure of NiC is interpreted as perturbed antiferromagnetic couplings of the localized angular...

Thermophysical properties of krypton-helium gas mixtures from ab initio pair potentials.

Science.gov (United States)

Jäger, Benjamin; Bich, Eckard

2017-06-07

A new potential energy curve for the krypton-helium atom pair was developed using supermolecular ab initio computations for 34 interatomic distances. Values for the interaction energies at the complete basis set limit were obtained from calculations with the coupled-cluster method with single, double, and perturbative triple excitations and correlation consistent basis sets up to sextuple-zeta quality augmented with mid-bond functions. Higher-order coupled-cluster excitations up to the full quadruple level were accounted for in a scheme of successive correction terms. Core-core and core-valence correlation effects were included. Relativistic corrections were considered not only at the scalar relativistic level but also using full four-component Dirac-Coulomb and Dirac-Coulomb-Gaunt calculations. The fitted analytical pair potential function is characterized by a well depth of 31.42 K with an estimated standard uncertainty of 0.08 K. Statistical thermodynamics was applied to compute the krypton-helium cross second virial coefficients. The results show a very good agreement with the best experimental data. Kinetic theory calculations based on classical and quantum-mechanical approaches for the underlying collision dynamics were utilized to compute the transport properties of krypton-helium mixtures in the dilute-gas limit for a large temperature range. The results were analyzed with respect to the orders of approximation of kinetic theory and compared with experimental data. Especially the data for the binary diffusion coefficient confirm the predictive quality of the new potential. Furthermore, inconsistencies between two empirical pair potential functions for the krypton-helium system from the literature could be resolved.

Calibration of Sn-119 isomer shift using ab initio wave function methods

NARCIS (Netherlands)

Kurian, Reshmi; Filatov, Michael

2009-01-01

The isomer shift for the 23.87 keV M1 resonant transition in the Sn-119 nucleus is calibrated with the help of ab initio calculations. The calibration constant alpha(Sn-119) obtained from Hartree-Fock (HF) calculations (alpha(HF)(Sn-119)=(0.081 +/- 0.002)a(0)(-3) mm/s) and from second-order

DNA oligonucleotide-cis-platin Binding: Ab initio interpretation of the vibrational spectra

Czech Academy of Sciences Publication Activity Database

Andrushchenko, Valery; Wieser, H.; Bouř, Petr

2007-01-01

Roč. 111, č. 39 (2007), s. 9714-9723 ISSN 1089-5639 R&D Projects: GA AV ČR IAA400550702; GA ČR GA202/07/0732 Institutional research plan: CEZ:AV0Z40550506 Keywords : cis - platin * DNA * vibrational spektra * ab initio Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.918, year: 2007

Quality-based fingerprint segmentation

CSIR Research Space (South Africa)

Mngenge, NA

2012-06-01

Full Text Available is block-wise, it utilizes the auto-correlation matrix of gradients and its eigenvalue to compute the score quality measure of each block. The score quality measures both local contrast and orientation in each block. The threshold is computed by taking...

Understanding hydration of Zn(2+) in hydrothermal fluids with ab initio molecular dynamics

NARCIS (Netherlands)

Liu, X.; Lu, X.; Wang, R.; Meijer, E.J.

2011-01-01

With ab initio molecular dynamics simulations, the free-energy profiles of hydrated Zn2+ are calculated for both gaseous and aqueous systems from ambient to supercritical conditions, and from the derived free-energy information, the speciation of hydrated Zn2+ has been revealed. It is shown that the

Conformational Sampling by Ab Initio Molecular Dynamics Simulations Improves NMR Chemical Shift Predictions

Czech Academy of Sciences Publication Activity Database

Dračínský, Martin; Möller, H. M.; Exner, T. E.

2013-01-01

Roč. 9, č. 8 (2013), s. 3806-3815 ISSN 1549-9618 R&D Projects: GA ČR GA13-24880S Institutional support: RVO:61388963 Keywords : ab initio molecular dynamics * NMR spectroscopy * DFT calculations * hydration Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.310, year: 2013

Pronuclear scoring as a predictor of embryo quality in in vitro fertilization program.

Directory of Open Access Journals (Sweden)

Piotr Jedrzejczak

2008-04-01

Full Text Available Many strategies have been proposed for the selection of viable embryos for transfer in human assisted reproduction. These have included morphological scoring criteria for 20, 28, 44 and 68 h after insemination. The embryo selection is based on morphology, degree of fragmentation and development to the 8-cell. All have shown some correlation with implantation. However, the overall success of these methods is still limited, with over 50% of all transferred embryos failing to implant. Pronuclear zygote morphology has gained much attention recently due to its positive value in predicting implantation and pregnancy. This prospective study involved 178 conventional IVF patients only. The key aspects of pronuclear scoring and namely the presence of a cytoplasmic halo were related to day 3 of development and morphology in a retrospective study. The Z-score and the presence/absence of a halo had significant effect on the rate of development on day 3 embryo. Low Z-score result in slow development and poor morphology. The absence of a halo also resulted in slow and poor development, low morphology, increased fragmentation.

Proposal for evaluating the quality of reports of surgical interventions in the treatment of trigeminal neuralgia: the Surgical Trigeminal Neuralgia Score.

Science.gov (United States)

Akram, Harith; Mirza, Bilal; Kitchen, Neil; Zakrzewska, Joanna M

2013-09-01

The aim of this study was to design a checklist with a scoring system for reporting on studies of surgical interventions for trigeminal neuralgia (TN) and to validate it by a review of the recent literature. A checklist with a scoring system, the Surgical Trigeminal Neuralgia Score (STNS), was devised partially based on the validated STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) criteria and customized for TN after a literature review and then applied to a series of articles. These articles were identified using a prespecified MEDLINE and Embase search covering the period from 2008 to 2010. Of the 584 articles found, 59 were studies of interventional procedures for TN that fulfilled the inclusion criteria and 56 could be obtained in full. The STNS was then applied independently by 3 of the authors. The maximum STNS came to 30, and was reliable and reproducible when used by the 3 authors who performed the scoring. The range of scores was 6-23.5, with a mean of 14 for all the journals. The impact factor scores of the journals in which the papers were published ranged from 0 to 4.8. Twenty-four of the studies were published in the Journal of Neurosurgery or in Neurosurgery. Studies published in neurosurgical journals ranked higher on the STNS scale than those published in nonneurosurgical journals. There was no statistically significant correlation between STNS and impact factors. Stereotactic radiosurgery (n = 25) and microvascular decompression (n = 15) were the most commonly reported procedures. The diagnostic criteria were stated in 35% of the studies, and 4 studies reported subtypes of TN. An increasing number of studies (46%) used the recommended Kaplan-Meier methodology for pain survival outcomes. The follow-up period was unclear in 8 studies, and 26 reported follow-ups of more than 5 years. Complications were reported fairly consistently but the temporal course was not always indicated. Direct interview, telephone conversation

Calcium ions in aqueous solutions: Accurate force field description aided by ab initio molecular dynamics and neutron scattering

Science.gov (United States)

Martinek, Tomas; Duboué-Dijon, Elise; Timr, Štěpán; Mason, Philip E.; Baxová, Katarina; Fischer, Henry E.; Schmidt, Burkhard; Pluhařová, Eva; Jungwirth, Pavel

2018-06-01

We present a combination of force field and ab initio molecular dynamics simulations together with neutron scattering experiments with isotopic substitution that aim at characterizing ion hydration and pairing in aqueous calcium chloride and formate/acetate solutions. Benchmarking against neutron scattering data on concentrated solutions together with ion pairing free energy profiles from ab initio molecular dynamics allows us to develop an accurate calcium force field which accounts in a mean-field way for electronic polarization effects via charge rescaling. This refined calcium parameterization is directly usable for standard molecular dynamics simulations of processes involving this key biological signaling ion.

Study on the surface hydroxyl group on solid breeding materials by ab-initio calculations

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Satoru; Taniguchi, Masaki [Tokyo Univ. (Japan). Faculty of Engineering

1996-10-01

The nature of -OH on the surface of Li{sub 2}O was analyzed with the ab-initio quantum chemical calculation technique. Calculation results showed that the stretching vibration of O-H is affected by the chemical species around the -OH. (author)

All electron ab initio investigations of the electronic states of the FeC molecule

DEFF Research Database (Denmark)

Shim, Irene; Gingerich, Karl A.

1999-01-01

The low lying electronic states of the molecule FeC have been investigated by performing all electron ab initio multi-configuration self-consistent-field (CASSCF) and multi reference configuration interaction (MRCI) calculations. The relativistic corrections for the one electron Darwin contact term...

All Electron ab initio Investigations of the Electronic States of the MoN Molecule

DEFF Research Database (Denmark)

Shim, Irene; Gingerich, Karl A.

1999-01-01

The low lying electronic states of the molecule MoN have been investigated by performing all electron ab initio multi-configuration self-consistent-field (CASSCF) calculations. The relativistic corrections for the one electron Darwin contact term and the relativistic mass-velocity correction have...

Reliability, construct and criterion validity of the KIDSCREEN-10 score: A short measure for children and adolescents' well-being and health-related quality of life

NARCIS (Netherlands)

Ravens-Sieberer, U.; Erhart, M.; Rajmil, L.; Herdman, M.; Auquier, P.; Bruil, J.; Power, M.; Duer, W.; Abel, T.; Czemy, L.; Mazur, J.; Czimbalmos, A.; Tountas, Y.; Hagquist, C.; Kilroe, J.

2010-01-01

Background: To assess the criterion and construct validity of the KIDSCREEN-10 well-being and health-related quality of life (HRQoL) score, a short version of the KIDSCREEN-52 and KIDSCREEN-27 instruments. Methods: The child self-report and parent report versions of the KIDSCREEN-10 were tested in a

Theoretical study of silicon carbide under irradiation at the nano scale: classical and ab initio modelling; Etude theorique a l'echelle nanometrique du carbure de silicium sous irradiation: modelisation classique et ab initio

Energy Technology Data Exchange (ETDEWEB)

Lucas, G

2006-10-15

The behaviour of silicon carbide under irradiation has been studied using classical and ab initio simulations, focusing on the nano scale elementary processes. First, we have been interested in the calculation of threshold displacement energies, which are difficult to determine both experimentally and theoretically, and also the associated Frenkel pairs. In the framework of this thesis, we have carried out simulations in classical and ab initio molecular dynamics. For the classical approach, two types of potentials have been used: the Tersoff potential, which led to non satisfactory results, and a new one which has been developed during this thesis. This potential allows a better modelling of SiC under irradiation than most of the empirical potentials available for SiC. It is based on the EDIP potential, initially developed to describe defects in silicon, that we have generalized to SiC. For the ab initio approach, the feasibility of the calculations has been validated and average energies of 19 eV for the C and 38 eV for the Si sublattices have been determined, close to the values empirically used in the fusion community. The results obtained with the new potential EDIP are globally in agreement with those values. Finally, the elementary processes involved in the crystal recovery have been studied by calculating the stability of the created Frenkel pairs and determining possible recombination mechanisms with the nudged elastic band method. (author)

High-throughput ab-initio dilute solute diffusion database.

Science.gov (United States)

Wu, Henry; Mayeshiba, Tam; Morgan, Dane

2016-07-19

We demonstrate automated generation of diffusion databases from high-throughput density functional theory (DFT) calculations. A total of more than 230 dilute solute diffusion systems in Mg, Al, Cu, Ni, Pd, and Pt host lattices have been determined using multi-frequency diffusion models. We apply a correction method for solute diffusion in alloys using experimental and simulated values of host self-diffusivity. We find good agreement with experimental solute diffusion data, obtaining a weighted activation barrier RMS error of 0.176 eV when excluding magnetic solutes in non-magnetic alloys. The compiled database is the largest collection of consistently calculated ab-initio solute diffusion data in the world.

Study of wide band-gap crystal LiCaAlF6 by IR-reflection spectroscopy and ab initio calculations

International Nuclear Information System (INIS)

Novikova, N.N.; Klimin, S.A.; Mavrin, B.N.

2017-01-01

Polarized IR-reflection spectra and results of ab initio calculations of vibrational and electronic properties of LiCaAlF6 single crystal are presented. It is shown that the crystal band gap is direct. Experimental and theoretical parameters are obtained for dipole-active and all phonons, respectively, including silent modes. Experimental IR-reflection and Raman spectra are well described in the frame of results obtained by ab initio calculations. The peculiarities are discussed concerning the structure of electronic bands, the interatomic interactions, the character of lattice vibrations, and the phonon dispersion.

Atomic defects in monolayer WSe2 tunneling FETs studied by systematic ab initio calculations

Science.gov (United States)

Wu, Jixuan; Fan, Zhiqiang; Chen, Jiezhi; Jiang, Xiangwei

2018-05-01

Atomic defects in monolayer WSe2 tunneling FETs (TFETs) are studied through systematic ab initio calculations aiming at performance predictions and enhancements. The effects of various defect positions and different passivation atoms are characterized in WSe2 TFETs by rigorous ab initio quantum transport simulations. It is suggested that the Se vacancy (VSe) defect located in the gate-controlled channel region tends to increase the OFF current (I off), whereas it can be well suppressed by oxygen passivation. It is demonstrated that chlorine (Cl) passivation at the source-side tunneling region can largely suppress I off, leading to an impressively improved on–off ratio (I on/I off) compared with that without any defect. However, it is also observed that randomly positioned atomic defects tend to induce significant fluctuation of the TFET output. Further discussions are made with focus on the performance-variability trade-off for robust circuit design.

Ab initio investigation of superconductivity in orthorhombic MgPtSi

Energy Technology Data Exchange (ETDEWEB)

Tütüncü, H.M., E-mail: tutuncu@sakarya.edu.tr [Sakarya Üniversitesi, Fen-Edebiyat Fakültesi, Fizik Bölümü, 54187, Adapazarı (Turkey); Sakarya Üniversitesi, BIMAYAM Biyomedikal, Manyetik ve Yarıiletken Malzemeler Araştırma Merkezi, 54187, Adapazarı (Turkey); Ertuǧrul Karaca [Sakarya Üniversitesi, Fen-Edebiyat Fakültesi, Fizik Bölümü, 54187, Adapazarı (Turkey); Srivastava, G.P. [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)

2016-07-15

We have performed an ab initio study of electronic, vibrational and superconducting properties of the orthorhombic MgPtSi by employing the density functional theory, a linear-response formalism, and the plane-wave pseudopotential method. Our electronic results suggest that the density of states at the Fermi level is primarily contributed by Pt 5d and Si 3p states with much smaller contribution from Mg electronic states. Phonon anomalies have been found for all three acoustic branches. Due to these phonon anomalies, the acoustic branches make large contributions to the average electron-phonon coupling parameter. From the Eliashberg spectral function, the value of average electron-phonon coupling parameter is found to 0.707. Using this value, the superconducting critical temperature is obtained to be 2.4 K, in excellent accordance with its experimental value of 2.5 K. - Highlights: • The electronic structure of MgPtSi is studied using ab initio pseudopotential method. • Phonons and electron–phonon interaction in MgPtSi are studied using a linear response theory. • The acoustic phonon modes couple more strongly with electrons. • The value of λ is found to be 0.707 which shows that MgPtSi is a conventional honon-mediated superconductor. • The calculated T{sub c} of 2.4 K is in excellent accordance with its experimental value of 2.5 K.

Ab initio NMR parameters of BrCH3 and ICH3 with relativistic and vibrational corrections

Science.gov (United States)

Uhlíková, Tereza; Urban, Štěpán

2018-05-01

This study is focused on two effects identified when NMR parameters are calculated based on first principles. These effects are 1. vibrational correction of properties when using ab initio optimized equilibrium geometry; 2. relativistic effects and limits of using the Flygare equation. These effects have been investigated and determined for nuclear spin-rotation constants and nuclear magnetic shieldings for the CH3Br and CH3I molecules. The most significant result is the difference between chemical shieldings determined based on the ab initio relativistic four-component Dirac-Coulomb Hamiltonian and chemical shieldings calculated using experimental values and the Flygare equation. This difference is approximately 320 ppm and 1290 ppm for 79Br and 127I in the CH3X molecule, respectively.

Image Quality Assessment via Quality-aware Group Sparse Coding

Directory of Open Access Journals (Sweden)

Minglei Tong

2014-12-01

Full Text Available Image quality assessment has been attracting growing attention at an accelerated pace over the past decade, in the fields of image processing, vision and machine learning. In particular, general purpose blind image quality assessment is technically challenging and lots of state-of-the-art approaches have been developed to solve this problem, most under the supervised learning framework where the human scored samples are needed for training a regression model. In this paper, we propose an unsupervised learning approach that work without the human label. In the off-line stage, our method trains a dictionary covering different levels of image quality patch atoms across the training samples without knowing the human score, where each atom is associated with a quality score induced from the reference image; at the on-line stage, given each image patch, our method performs group sparse coding to encode the sample, such that the sample quality can be estimated from the few labeled atoms whose encoding coefficients are nonzero. Experimental results on the public dataset show the promising performance of our approach and future research direction is also discussed.

Reliability of a visual scoring system with fluorescent tracers to assess dermal pesticide exposure.

Science.gov (United States)

Aragon, Aurora; Blanco, Luis; Lopez, Lylliam; Liden, Carola; Nise, Gun; Wesseling, Catharina

2004-10-01

We modified Fenske's semi-quantitative 'visual scoring system' of fluorescent tracer deposited on the skin of pesticide applicators and evaluated its reproducibility in the Nicaraguan setting. The body surface of 33 farmers, divided into 31 segments, was videotaped in the field after spraying with a pesticide solution containing a fluorescent tracer. A portable UV lamp was used for illumination in a foldaway dark room. The videos of five farmers were randomly selected. The scoring was based on a matrix with extension of fluorescent patterns (scale 0-5) on the ordinate and intensity (scale 0-5) on the abscissa, with the product of these two ranks as the final score for each body segment (0-25). Five medical students rated and evaluated the quality of 155 video images having undergone 4 h of training. Cronbach alpha coefficients and two-way random effects intraclass correlation coefficients (ICC) with absolute agreement were computed to assess inter-rater reliability. Consistency was high (Cronbach alpha = 0.96), but the scores differed substantially between raters. The overall ICC was satisfactory [0.75; 95% confidence interval (CI) = 0.62-0.83], but it was lower for intensity (0.54; 95% CI = 0.40-0.66) and higher for extension (0.80; 95% CI = 0.71-0.86). ICCs were lowest for images with low scores and evaluated as low quality, and highest for images with high scores and high quality. Inter-rater reliability coefficients indicate repeatability of the scoring system. However, field conditions for recording fluorescence should be improved to achieve higher quality images, and training should emphasize a better mechanism for the reading of body areas with low contamination.

Ab initio studies on [bmim][PF6]–CO2 mixture and CO2 clusters

Indian Academy of Sciences (India)

Wintec

Ionic liquids; supercritical carbon dioxide; ab initio; molecular dynamics. 1. Introduction .... Several experi- mental and simulation studies have been carried out to .... from an analysis of its electronic polarizability (α), which is a measure of the ...

Ab initio excited states calculations of Kr3+, probing semi-empirical modelling

Czech Academy of Sciences Publication Activity Database

Milko, Petr; Kalus, R.; Paidarová, Ivana; Hrušák, Jan; Gadéa, F. X.

-, 23 June (2009), s. 25 ISSN 1432-2234 R&D Projects: GA AV ČR IAA100400501 Institutional research plan: CEZ:AV0Z40400503 Keywords : cluster modelling * rare gas ions * ab initio potential energie * evaporation energies Subject RIV: CF - Physical ; Theoretical Chemistry http://www.springerlink.com/content/100493/?Content+Status=Accepted&sort=p_OnlineDate&sortorder=desc&v=condensed&o=20

Ab initio quantum-enhanced optical phase estimation using real-time feedback control

DEFF Research Database (Denmark)

Berni, Adriano; Gehring, Tobias; Nielsen, Bo Melholt

2015-01-01

of a quantum-enhanced and fully deterministic ab initio phase estimation protocol based on real-time feedback control. Using robust squeezed states of light combined with a real-time Bayesian adaptive estimation algorithm, we demonstrate deterministic phase estimation with a precision beyond the quantum shot...... noise limit. The demonstrated protocol opens up new opportunities for quantum microscopy, quantum metrology and quantum information processing....

[Results of applying a paediatric early warning score system as a healthcare quality improvement plan].

Science.gov (United States)

Rivero-Martín, M J; Prieto-Martínez, S; García-Solano, M; Montilla-Pérez, M; Tena-Martín, E; Ballesteros-García, M M

2016-06-01

The aims of this study were to introduce a paediatric early warning score (PEWS) into our daily clinical practice, as well as to evaluate its ability to detect clinical deterioration in children admitted, and to train nursing staff to communicate the information and response effectively. An analysis was performed on the implementation of PEWS in the electronic health records of children (0-15 years) in our paediatric ward from February 2014 to September 2014. The maximum score was 6. Nursing staff reviewed scores >2, and if >3 medical and nursing staff reviewed it. Monitoring indicators: % of admissions with scoring; % of complete data capture; % of scores >3; % of scores >3 reviewed by medical staff, % of changes in treatment due to the warning system, and number of patients who needed Paediatric Intensive Care Unit (PICU) admission, or died without an increased warning score. The data were collected from all patients (931) admitted. The scale was measured 7,917 times, with 78.8% of them with complete data capture. Very few (1.9%) showed scores >3, and 14% of them with changes in clinical management (intensifying treatment or new diagnostic tests). One patient (scored 2) required PICU admission. There were no deaths. Parents or nursing staff concern was registered in 80% of cases. PEWS are useful to provide a standardised assessment of clinical status in the inpatient setting, using a unique scale and implementing data capture. Because of the lack of severe complications requiring PICU admission and deaths, we will have to use other data to evaluate these scales. Copyright © 2016 SECA. Published by Elsevier Espana. All rights reserved.

Effect of clinical and laboratory parameters on quality of life in celiac patients using celiac disease-specific quality of life scores.

Science.gov (United States)

Lee, Jungmin; Clarke, Kofi

2017-11-01

Health-related quality of life (HR-QOL) in patients with celiac disease is reduced compared to the general population. We investigated the association between HR-QOL and clinical, laboratory findings using the previously validated CD-QOL (celiac disease-specific quality of life) instrument in patients with celiac disease. To our knowledge, no study has previously explored the relationship between HR-QOL and clinical, laboratory parameters in celiac patients. Patients who received care at the Allegheny Health Network Celiac Center, Pittsburgh, PA were asked to complete the CD-QOL questionnaire. A cross sectional study with predetermined clinical and laboratory parameters was performed. Data collected included IgA anti-tissue transglutaminase (tTG) antibody titers, iron studies, calcium, vitamin A, B12, 25 OH vitamin D, and E levels. Correlation between clinical findings and CD-QOL was also assessed. Seventy-eight out of 124 patients who completed the questionnaire was included in the analysis. Patients with concomitant irritable bowel syndrome (IBS) had significantly reduced HR-QOL with CD-QOL score of 52.4 ± 11.3 vs. 44.6 ± 12.9 in those without IBS (p = .009). There was no difference in HR-QOL in relation to IgA tTG titers or vitamin D levels. Of note, there was a trend towards correlation between higher level of vitamin E and better QOL (r = -0.236, p = .074). Celiac patients with concomitant IBS have reduced HR-QOL. There was no statistically significant association between HR-QOL and laboratory parameters or levels of micronutrients.

Efficacy of the semiempirical sparkle model as compared to ECP ab-initio calculations for the prediction of ligand field parameters of europium (III) complexes

International Nuclear Information System (INIS)

Freire, Ricardo O.; Rocha, Gerd B.; Albuquerque, Rodrigo Q.; Simas, Alfredo M.

2005-01-01

The second version of the sparkle model for the calculation of lanthanide complexes (SMLC II) as well as ab-initio calculations (HF/STO-3G and HF/3-21G) have been used to calculate the geometries of a series of europium (III) complexes with different coordination numbers (CN=7, 8 and 9), ligating atoms (O and N) and ligands (mono, bi and polydentate). The so-called ligand field parameters, Bqk's, have been calculated from both SMLC II and ab-initio optimized structures and compared to the ones calculated from crystallographic data. The results show that the SMLC II model represents a significant improvement over the previous version (SMLC) and has given good results when compared to ab-initio methods, which demand a much higher computational effort. Indeed, ab-initio methods take around a hundred times more computing time than SMLC. As such, our results indicate that our sparkle model can be a very useful and a fast tool when applied to the prediction of both ground state geometries and ligand field parameters of europium (III) complexes

Determining utility values in patients with anterior cruciate ligament tears using clinical scoring systems

Directory of Open Access Journals (Sweden)

Szucs Thomas

2011-08-01

Full Text Available Abstract Background Several instruments and clinical scoring systems have been established to evaluate patients with ligamentous knee injuries. A comparison of individual articles in the literature is challenging, not only because of heterogeneity in methodology, but also due to the variety of the scoring systems used to document clinical outcomes. There is limited information about the correlation between used scores and quality of life with no information being available on the impact of each score on the utility values. The aim of this study was to compare the most commonly used scores for evaluating patients with anterior cruciate ligament (ACL injuries, and to establish corresponding utility values. These values will be used for the interpretation and comparison of outcome results in the currently available literature for different treatment options. Methods Four hypothetical vignettes were defined, based on different levels of activities after rupture of the ACL to simulate typical situations seen in daily practice. A questionnaire, including the Health Utility Index (HUI for utility values, the IKDC subjective score, the Lysholm and the Tegner score, was created and 25 orthopedic surgeons were asked to fill the questionnaire for each hypothetical patient as proxies for all patients they had treated and who would fit in that hypothetical vignette. Results The utility value as an indicator for quality of life increased with the level of activity. Having discomforts already during normal activities of daily living was rated with a mean utility value of 0.37 ± 0.19, half of that of a situation where mild sport activity was possible without discomfort (0.78 ± 0.11. All investigated scores were able to distinguish clearly (p Conclusions Here we report the correlation between the most commonly used scores for the assessment of patients with a ruptured ACL and utility values as an indicator of quality of life. Assumptions were based on expert

Measuring Inpatient Rehabilitation Facility Quality of Care: Discharge Self-Care Functional Status Quality Measure.

Science.gov (United States)

Pardasaney, Poonam K; Deutsch, Anne; Iriondo-Perez, Jeniffer; Ingber, Melvin J; McMullen, Tara

2018-06-01

To describe the calculation and psychometric properties of the discharge self-care functional status quality measure implemented in the Centers for Medicare & Medicaid Services' (CMS) Inpatient Rehabilitation Facility (IRF) Quality Reporting Program on October 1, 2016. Medicare fee-for-service (FFS) patients from 38 IRFs that participated in the CMS Post-Acute Care Payment Reform Demonstration were included in this cohort study. Data came from the Continuity Assessment Record and Evaluation Item Set, IRF-Patient Assessment Instrument, and Medicare claims. For each patient, we calculated an expected discharge self-care score, risk-adjusted for demographic and baseline clinical characteristics. The performance score of each IRF equaled the percentage of patient stays where the observed discharge self-care score met or exceeded the expected score. We assessed the measure's discriminatory ability across IRFs and reliability. IRFs. Medicare FFS patients aged ≥21 years (N=4769). Not applicable. Facility-level discharge self-care quality measure performance score. A total of 4769 patient stays were included; 57% of stays were in women, and 12.1% were in patients aged quality measure showed strong reliability, with intraclass correlation coefficients of .91. The discharge self-care quality measure showed strong discriminatory ability and reliability, representing an important initial step in evaluation of IRF self-care outcomes. A wide range in performance scores suggested a gap in quality of care across IRFs. Future work should include testing the measure with nationwide data from all IRFs. Published by Elsevier Inc.

Ab initio study of weakly bound halogen complexes: RX⋯PH3.

Science.gov (United States)

Georg, Herbert C; Fileti, Eudes E; Malaspina, Thaciana

2013-01-01

Ab initio calculations were employed to study the role of ipso carbon hybridization in halogenated compounds RX (R=methyl, phenyl, acetyl, H and X=F, Cl, Br and I) and its interaction with a phosphorus atom, as occurs in the halogen bonded complex type RX⋯PH3. The analysis was performed using ab initio MP2, MP4 and CCSD(T) methods. Systematic energy analysis found that the interaction energies are in the range -4.14 to -11.92 kJ mol(-1) (at MP2 level without ZPE correction). Effects of electronic correlation levels were evaluated at MP4 and CCSD(T) levels and a reduction of up to 27% in interaction energy obtained in MP2 was observed. Analysis of the electrostatic maps confirms that the PhCl⋯PH3 and all MeX⋯PH3 complexes are unstable. NBO analysis suggested that the charge transfer between the moieties is bigger when using iodine than bromine and chlorine. The electrical properties of these complexes (dipole and polarizability) were determined and the most important observed aspect was the systematic increase at the dipole polarizability, given by the interaction polarizability. This increase is in the range of 0.7-6.7 u.a. (about 3-7%).

Phase diagrams from ab-initio calculations: Re-W and Fe-B

Energy Technology Data Exchange (ETDEWEB)

Hammerschmidt, Thomas; Bialon, Arthur; Palumbo, Mauro; Fries, Suzana G.; Drautz, Ralf [ICAMS, Ruhr-Universitaet Bochum (Germany)

2011-07-01

The CALPHAD (CaLculation of Phase Diagrams) method relies on Gibbs energy databases and is of limited predictive power in cases where only limited experimental data is available for constructing the Gibbs energy databases. This is problematic for, e.g., the calculation of the phase transformation kinetics within phase field simulations that not only require the thermodynamic equilibrium data but also information on metastable phases. Such information is difficult to obtain directly from experiment but ab-initio calculations may supplement experimental databases as they comprise metastable phases and arbitrary chemical compositions. We present simulations for two prototypical systems: Re-W and Fe-B. For both systems we calculate the heat of formation for an extensive set of structures using ab-initio calculations and employ the total energies in CALPHAD in order to determine the corresponding phase diagrams. We account for the configurational entropy within the Bragg-Williams approximation and neglect the phenomenological excess-term that is commonly used in CALPHAD as well as the contribution of phonons and electronic excitations to the free energy. According to our calculations the complex intermetallic phases in Re-W are stabilized by the configurational entropy. For Fe-B, we calculate metastable and stable phase diagrams including recently predicted new stable phases.

The STAR score: a method for auditing clinical records

Science.gov (United States)

Tuffaha, H

2012-01-01

INTRODUCTION Adequate medical note keeping is critical in delivering high quality healthcare. However, there are few robust tools available for the auditing of notes. The aim of this paper was to describe the design, validation and implementation of a novel scoring tool to objectively assess surgical notes. METHODS An initial ‘path finding’ study was performed to evaluate the quality of note keeping using the CRABEL scoring tool. The findings prompted the development of the Surgical Tool for Auditing Records (STAR) as an alternative. STAR was validated using inter-rater reliability analysis. An audit cycle of surgical notes using STAR was performed. The results were analysed and a structured form for the completion of surgical notes was introduced to see if the quality improved in the next audit cycle using STAR. An education exercise was conducted and all participants said the exercise would change their practice, with 25% implementing major changes. RESULTS Statistical analysis of STAR showed that it is reliable (Cronbach’s a = 0.959). On completing the audit cycle, there was an overall increase in the STAR score from 83.344% to 97.675% (p<0.001) with significant improvements in the documentation of the initial clerking from 59.0% to 96.5% (p<0.001) and subsequent entries from 78.4% to 96.1% (p<0.001). CONCLUSIONS The authors believe in the value of STAR as an effective, reliable and reproducible tool. Coupled with the application of structured forms to note keeping, it can significantly improve the quality of surgical documentation and can be implemented universally. PMID:22613300

The STAR score: a method for auditing clinical records.

Science.gov (United States)

Tuffaha, H; Amer, T; Jayia, P; Bicknell, C; Rajaretnam, N; Ziprin, P

2012-05-01

Adequate medical note keeping is critical in delivering high quality healthcare. However, there are few robust tools available for the auditing of notes. The aim of this paper was to describe the design, validation and implementation of a novel scoring tool to objectively assess surgical notes. An initial 'path finding' study was performed to evaluate the quality of note keeping using the CRABEL scoring tool. The findings prompted the development of the Surgical Tool for Auditing Records (STAR) as an alternative. STAR was validated using inter-rater reliability analysis. An audit cycle of surgical notes using STAR was performed. The results were analysed and a structured form for the completion of surgical notes was introduced to see if the quality improved in the next audit cycle using STAR. An education exercise was conducted and all participants said the exercise would change their practice, with 25% implementing major changes. Statistical analysis of STAR showed that it is reliable (Cronbach's α = 0.959). On completing the audit cycle, there was an overall increase in the STAR score from 83.344% to 97.675% (p < 0.001) with significant improvements in the documentation of the initial clerking from 59.0% to 96.5% (p < 0.001) and subsequent entries from 78.4% to 96.1% (p < 0.001). The authors believe in the value of STAR as an effective, reliable and reproducible tool. Coupled with the application of structured forms to note keeping, it can significantly improve the quality of surgical documentation and can be implemented universally.

[Association of occupational stress with quality of working life].

Science.gov (United States)

Zhang, Qin; Lan, Ya-Jia; Chen, Hong-Mei

2011-07-01

To assess occupational stress and quality of working life (QWL) and their association in workers with different jobs. The Occupational Stress Inventory Revised Edition (OSI-R) and Quality of Working Life Scale (QWL7-32) were administered to 194 workers in the Liaohe Oilfield. The association between occupational stress and quality of working life was analysed by controlling job types and other confounding variables. Office workers had significantly lower scores in occupational role questionnaire (ORQ) and personal strain questionnaire (PSQ) and higher scores in personal resources questionnaire (PRQ) and QWL than physical laborers (P<0.05). The PSQ scores were positively correlated with the ORQ scores and negatively correlated with the PRQ scores. The QWL scores were negatively correlated with the ORQ and PSQ scores, and positively correlated with the PRQ scores (P<0.001). The QWL scores changed with job types. The QWL scores declined with the increase of stress levels (P<0.01). ORQ, role boundary (RB), role insufficiency (RI), physical environment (PE), PSQ, vocational strain (VS), interpersonal strain (IS) and PRQ had a significant impact on quality of working life (P<0.01). Occupational stress is associated with quality of working life. Quality of working life can be improved through control of occupational stress.

Investigation of the Hydroxylation Mechanism of Noncoupled Copper Oxygenases by Ab Initio Molecular Dynamics Simulations

Czech Academy of Sciences Publication Activity Database

Meliá, C.; Ferrer, S.; Řezáč, Jan; Parisel, O.; Reinaud, O.; Moliner, V.; de la Lande, A.

2013-01-01

Roč. 19, č. 51 (2013), s. 17328-17337 ISSN 0947-6539 Institutional support: RVO:61388963 Keywords : ab initio calculations * copper * electron transfer * enzymes * molecular dynamics * reaction mechanisms Subject RIV: CC - Organic Chemistry Impact factor: 5.696, year: 2013

Ab-initio modeling of an iron laser-induced plasma: Comparison between theoretical and experimental atomic emission spectra

International Nuclear Information System (INIS)

Colgan, J.; Judge, E.J.; Kilcrease, D.P.; Barefield, J.E.

2014-01-01

We report on efforts to model the Fe emission spectrum generated from laser-induced breakdown spectroscopy (LIBS) measurements on samples of pure iron oxide (Fe 2 O 3 ). Our modeling efforts consist of several components. We begin with ab-initio atomic structure calculations performed by solving the Hartree–Fock equations for the neutral and singly ionized stages of Fe. Our energy levels are then adjusted to their experimentally known values. The atomic transition probabilities and atomic collision quantities are also computed in an ab-initio manner. We perform LTE or non-LTE calculations that generate level populations and, subsequently, an emission spectrum for the iron plasma for a range of electron temperatures and electron densities. Such calculations are then compared to the experimental spectrum. We regard our work as a preliminary modeling effort that ultimately strives towards the modeling of emission spectra from even more complex samples where less atomic data are available. - Highlights: • LIBS plasma of iron oxide • Ab-initio theoretical Modeling • Discussion of LTE versus non-LTE criteria and assessment • Boltzmann plots for Fe—determination of when LTE is a valid assumption • Emission spectra for Fe—comparison of theoretical modeling and measurement: good agreement obtained

Field theoretic approach to dynamical orbital localization in ab initio molecular dynamics

International Nuclear Information System (INIS)

Thomas, Jordan W.; Iftimie, Radu; Tuckerman, Mark E.

2004-01-01

Techniques from gauge-field theory are employed to derive an alternative formulation of the Car-Parrinello ab initio molecular-dynamics method that allows maximally localized Wannier orbitals to be generated dynamically as the calculation proceeds. In particular, the Car-Parrinello Lagrangian is mapped onto an SU(n) non-Abelian gauge-field theory and the fictitious kinetic energy in the Car-Parrinello Lagrangian is modified to yield a fully gauge-invariant form. The Dirac gauge-fixing method is then employed to derive a set of equations of motion that automatically maintain orbital locality by restricting the orbitals to remain in the 'Wannier gauge'. An approximate algorithm for integrating the equations of motion that is stable and maintains orbital locality is then developed based on the exact equations of motion. It is shown in a realistic application (64 water molecules plus one hydrogen-chloride molecule in a periodic box) that orbital locality can be maintained with only a modest increase in CPU time. The ability to keep orbitals localized in an ab initio molecular-dynamics calculation is a crucial ingredient in the development of emerging linear scaling approaches

Improving Citation Network Scoring by Incorporating Author and Program Committee Reputation

Directory of Open Access Journals (Sweden)

Dineshi Peiris

2016-06-01

Full Text Available Publication venues play an important role in the scholarly communication process. The number of publication venues has been increasing yearly, making it difficult for researchers to determine the most suitable venue for their publication. Most existing methods use citation count as the metric to measure the reputation of publication venues. However, this does not take into account the quality of citations. Therefore, it is vital to have a publication venue quality estimation mechanism. The ultimate goal of this research project is to develop a novel approach for ranking publication venues by considering publication history. The main aim of this research work is to propose a mechanism to identify the key Computer Science journals and conferences from various fields of research. Our approach is completely based on the citation network represented by publications. A modified version of the PageRank algorithm is used to compute the ranking scores for each publication. In our publication ranking method, there are many aspects that contribute to the importance of a publication, including the number of citations, the rating of the citing publications, the time metric and the authors’ reputation. Known publication venue scores have been formulated by using the scores of the publications. New publication venue ranking is taken care by the scores of Program Committee members which derive from their ranking scores as authors. Experimental results show that our publication ranking method reduces the bias against more recent publications, while also providing a more accurate way to determine publication quality.

On the room-temperature phase diagram of high pressure hydrogen: An ab initio molecular dynamics perspective and a diffusion Monte Carlo study

International Nuclear Information System (INIS)

Chen, Ji; Ren, Xinguo; Li, Xin-Zheng; Alfè, Dario; Wang, Enge

2014-01-01

The finite-temperature phase diagram of hydrogen in the region of phase IV and its neighborhood was studied using the ab initio molecular dynamics (MD) and the ab initio path-integral molecular dynamics (PIMD). The electronic structures were analyzed using the density-functional theory (DFT), the random-phase approximation, and the diffusion Monte Carlo (DMC) methods. Taking the state-of-the-art DMC results as benchmark, comparisons of the energy differences between structures generated from the MD and PIMD simulations, with molecular and dissociated hydrogens, respectively, in the weak molecular layers of phase IV, indicate that standard functionals in DFT tend to underestimate the dissociation barrier of the weak molecular layers in this mixed phase. Because of this underestimation, inclusion of the quantum nuclear effects (QNEs) in PIMD using electronic structures generated with these functionals leads to artificially dissociated hydrogen layers in phase IV and an error compensation between the neglect of QNEs and the deficiencies of these functionals in standard ab initio MD simulations exists. This analysis partly rationalizes why earlier ab initio MD simulations complement so well the experimental observations. The temperature and pressure dependencies for the stability of phase IV were also studied in the end and compared with earlier results

Quality of life in obese children

Directory of Open Access Journals (Sweden)

Lital Moro Bass

2009-09-01

Full Text Available Objective: To assess quality of life in obese children. Methods: A cross-sectional study was conducted with 30 obese children who attended the Health Promotion Center of Einstein Program in Paraisópolis Community. The following instruments were applied: quality of life assessment questionnaire; a questionnaire prepared by the authors and a survey in medical charts. Rresults: In the group of 30 obese children, 57% were female, ages ranging from four to ten years. The mean total score obtained through the quality of life assessment of obese children was 48.5. As to the four factors considered in the quality of life scale, leisure achieved the highest score, and autonomy the lowest. Regarding the results concerning each item of the quality of life assessment scale, the highest ranked items were those related to birthday parties and vacations. The lowest were related to admission to hospital and be away from the family. Cconclusion: The findings of the present study concerning the general score of quality of life assessment in obese children was lower than those observed in studies evaluating quality of life in healthy children and children with associated disease, but no negative impact in the quality of life of obese children was demonstrated, although the total score was close to the cutoff score (< 48.

Development of the siriraj clinical asthma score.

Science.gov (United States)

Vichyanond, Pakit; Veskitkul, Jittima; Rienmanee, Nuanphong; Pacharn, Punchama; Jirapongsananuruk, Orathai; Visitsunthorn, Nualanong

2013-09-01

Acute asthmatic attack in children commonly occurs despite the introduction of effective controllers such as inhaled corticosteroids and leukotriene modifiers. Treatment of acute asthmatic attack requires proper evaluation of attack severity and appropriate selection of medical therapy. In children, measurement of lung function is difficult during acute attack and thus clinical asthma scoring may aid physician in making further decision regarding treatment and admission. We enrolled 70 children with acute asthmatic attack with age range from 1 to 12 years (mean ± SD = 51.5 ± 31.8 months) into the study. Twelve selected asthma severity items were assessed by 2 independent observers prior to administration of salbutamol nebulization (up to 3 doses at 20 minutes interval). Decision for further therapy and admission was made by emergency department physician. Three different scoring systems were constructed from items with best validity. Sensitivity, specificity and accuracy of these scores were assessed. Inter-rater reliability was assessed for each score. Review of previous scoring systems was also conducted and reported. Three severity items had poor validity, i.e., cyanosis, depressed cerebral function, and I:E ratio (p > 0.05). Three items had poor inter-rater reliability, i.e., breath sound quality, air entry, and I:E ratio. These items were omitted and three new clinical scores were constructed from the remaining items. Clinical scoring system comprised retractions, dyspnea, O2 saturation, respiratory rate and wheezing (rangeof score 0-10) gave the best accuracy and inter-rater variability and were chosen for clinical use-Siriraj Clinical Asthma Score (SCAS). A Clinical Asthma Score that is simple, relatively easy to administer and with good validity and variability is essential for treatment of acute asthma in children. Several good candidate scores have been introduced in the past. We described the development of the Siriraj Clinical Asthma Score (SCAS) in

Computationally efficient and quantitatively accurate multiscale simulation of solid-solution strengthening by ab initio calculation

Czech Academy of Sciences Publication Activity Database

Ma, D.; Friák, Martin; von Pezold, J.; Raabe, D.; Neugebauer, J.

2015-01-01

Roč. 85, FEB (2015), s. 53-66 ISSN 1359-6454 Institutional support: RVO:68081723 Keywords : Solid-solution strengthening * DFT * Peierls–Nabarro model * Ab initio * Al alloys Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.058, year: 2015

Ab initio methods for electron-molecule collisions

International Nuclear Information System (INIS)

Collins, L.A.; Schneider, B.I.

1987-01-01

This review concentrates on the recent advances in treating the electronic aspect of the electron-molecule interaction and leaves to other articles the description of the rotational and vibrational motions. Those methods which give the most complete treatment of the direct, exchange, and correlation effects are focused on. Such full treatments are generally necessary at energies below a few Rydbergs (≅ 60 eV). This choice unfortunately necessitates omission of those active and vital areas devoted to the development of model potentials and approximate scattering formulations. The ab initio and model approaches complement each other and are both extremely important to the full explication of the electron-scattering process. Due to the rapid developments of recent years, the approaches that provide the fullest treatment are concentrated on. 81 refs

Routine calculation of ab initio melting curves: application to aluminum

OpenAIRE

Robert, Grégory; Legrand, Philippe; Arnault, Philippe; Desbiens, Nicolas; Clérouin, Jean

2014-01-01

We present a simple, fast, and reliable method to compute the melting curves of materials with ab initio molecular dynamics. It is based on the two-phase thermodynamic model of [Lin et al., J. Chem. Phys. 119, 11792 (2003)] and its improved version given by [Desjarlais, Phys. Rev. E, 88, 062145 (2013)]. In this model, the velocity autocorrelation function is utilized to calculate the contribution of the nuclei motion to the entropy of the solid and liquid phases. It is then possible to find t...

Molecular structure determination of cyclooctane by Ab Initio and electron diffraction methods in the gas phase

International Nuclear Information System (INIS)

Almeida, Wagner B. de

2000-01-01

The determination of the molecular structure of molecules is of fundamental importance in chemistry. X-rays and electron diffraction methods constitute in important tools for the elucidation of the molecular structure of systems in the solid state and gas phase, respectively. The use of quantum mechanical molecular orbital ab initio methods offer an alternative for conformational analysis studies. Comparison between theoretical results and those obtained experimentally in the gas phase can make a significant contribution for an unambiguous determination of the geometrical parameters. In this article the determination for an unambiguous determination of the geometrical parameters. In this article the determination of the molecular structure of the cyclooctane molecule by electron diffraction in the gas phase an initio calculations will be addressed, providing an example of a comparative analysis of theoretical and experimental predictions. (author)

Ab initio molecular dynamics approach to a quantitative description of ion pairing in water

Czech Academy of Sciences Publication Activity Database

Pluhařová, Eva; Maršálek, Ondřej; Schmidt, B.; Jungwirth, Pavel

2013-01-01

Roč. 4, č. 23 (2013), s. 4177-4181 ISSN 1948-7185 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : ion pairing * charge transfer * water * ab initio molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 6.687, year: 2013

Carbon monoxide adsorption on alkali and proton-exchanged chabazite: an ab-initio periodic study using the CRYSTAL code

Science.gov (United States)

Ugliengo, P.; Busco, C.; Civalleri, B.; Zicovich-Wilson, C. M.

Ab initio periodic calculations based on local Gaussian basis sets as coded in the CRYSTAL program have been performed to investigate the structure, the binding energy and the vibrational features of carbon monoxide adsorbed on H+, Li+, Na+ and K+-exchanged chabazite (Si/Al = 11/1, i.e. one Al atom per unit cell). The hybrid B3LYP functional has been adopted for all calculations with a polarized double-zeta quality basis set. The B3LYP binding energies (BSSE corrected) are 16.0, 24.6, 20.4 and 5.1 kJ/mol for H+, Li+, Na+ and K+-exchanged chabazite, respectively. Corresponding CO hypsochromic stretching frequency shifts are 47, 68, 43 and 33 cm-1, respectively. Comparison with the case of CO interacting with bare alkali cations and the available experimental data on a variety of zeolites has also been addressed.

Improved parametric fits for the HeH2 ab initio energy surface

International Nuclear Information System (INIS)

Muchnick, P.

1992-01-01

A brief history of the development of ab initio calculations for the HeH 2 quasi-molecule energy surface, and the parametric fits to these ab initio calculations, is presented. The concept of 'physical reasonableness' of the parametric fit is discussed. Several new improved parametric fits for the energy surface, meeting these requirements, are then proposed. One fit extends the Russek-Garcia parametric fit for the deep repulsion region to include r-dependent parameters, resulting in a more physically reasonable fit with smaller average error. This improved surface fit is applied to quasi-elastic collisions of He on H 2 in the impulse approximation. Previous classical calculations of the scaled inelastic vibrorotational excitation energy distributions are improved with this more accurate parametric fit of the energy surface and with the incorporation of quantum effects in vibrational excitation. It is shown that Sigmund's approach in developing his scaling law is incomplete in the contribution of the three-body interactions to vibrational excitation of the H 2 molecule is concerned. The Sigmund theory is extended to take into account for r-dependency of three-body interactions. A parametric fit for the entire energy surface from essentially 0 ≤R≤∞ and 1.2≤r≤1.6 a.u., where R is the intermolecular spacing and r is the hydrogen bonding length, is also presented. This fit is physically reasonable in all asymptotic limits. This first, full surface parametric fit is based primarily upon a composite of ab initio studies by Russek and Garcia and Meyer, Hariharan and Kutzelnigg. Parametric fits for the H 2 (1sσ g ) 2 , H 2 + (1sσ g ), H 2 + (2pσ u ) and (LiH 2 ) + energy surfaces are also presented. The new parametric fits for H 2 , H 2 + (1sσ g ) are shown to be improvements over the well-known Morse potentials for these surfaces

Learning Receptive Fields and Quality Lookups for Blind Quality Assessment of Stereoscopic Images.

Science.gov (United States)

Shao, Feng; Lin, Weisi; Wang, Shanshan; Jiang, Gangyi; Yu, Mei; Dai, Qionghai

2016-03-01

Blind quality assessment of 3D images encounters more new challenges than its 2D counterparts. In this paper, we propose a blind quality assessment for stereoscopic images by learning the characteristics of receptive fields (RFs) from perspective of dictionary learning, and constructing quality lookups to replace human opinion scores without performance loss. The important feature of the proposed method is that we do not need a large set of samples of distorted stereoscopic images and the corresponding human opinion scores to learn a regression model. To be more specific, in the training phase, we learn local RFs (LRFs) and global RFs (GRFs) from the reference and distorted stereoscopic images, respectively, and construct their corresponding local quality lookups (LQLs) and global quality lookups (GQLs). In the testing phase, blind quality pooling can be easily achieved by searching optimal GRF and LRF indexes from the learnt LQLs and GQLs, and the quality score is obtained by combining the LRF and GRF indexes together. Experimental results on three publicly 3D image quality assessment databases demonstrate that in comparison with the existing methods, the devised algorithm achieves high consistent alignment with subjective assessment.

Efficient approach to compute melting properties fully from ab initio with application to Cu

Science.gov (United States)

Zhu, Li-Fang; Grabowski, Blazej; Neugebauer, Jörg

2017-12-01

Applying thermodynamic integration within an ab initio-based free-energy approach is a state-of-the-art method to calculate melting points of materials. However, the high computational cost and the reliance on a good reference system for calculating the liquid free energy have so far hindered a general application. To overcome these challenges, we propose the two-optimized references thermodynamic integration using Langevin dynamics (TOR-TILD) method in this work by extending the two-stage upsampled thermodynamic integration using Langevin dynamics (TU-TILD) method, which has been originally developed to obtain anharmonic free energies of solids, to the calculation of liquid free energies. The core idea of TOR-TILD is to fit two empirical potentials to the energies from density functional theory based molecular dynamics runs for the solid and the liquid phase and to use these potentials as reference systems for thermodynamic integration. Because the empirical potentials closely reproduce the ab initio system in the relevant part of the phase space the convergence of the thermodynamic integration is very rapid. Therefore, the proposed approach improves significantly the computational efficiency while preserving the required accuracy. As a test case, we apply TOR-TILD to fcc Cu computing not only the melting point but various other melting properties, such as the entropy and enthalpy of fusion and the volume change upon melting. The generalized gradient approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional and the local-density approximation (LDA) are used. Using both functionals gives a reliable ab initio confidence interval for the melting point, the enthalpy of fusion, and entropy of fusion.

Differences of wells scores accuracy, caprini scores and padua scores in deep vein thrombosis diagnosis

Science.gov (United States)

Gatot, D.; Mardia, A. I.

2018-03-01

Deep Vein Thrombosis (DVT) is the venous thrombus in lower limbs. Diagnosis is by using venography or ultrasound compression. However, these examinations are not available yet in some health facilities. Therefore many scoring systems are developed for the diagnosis of DVT. The scoring method is practical and safe to use in addition to efficacy, and effectiveness in terms of treatment and costs. The existing scoring systems are wells, caprini and padua score. There have been many studies comparing the accuracy of this score but not in Medan. Therefore, we are interested in comparative research of wells, capriniand padua score in Medan.An observational, analytical, case-control study was conducted to perform diagnostic tests on the wells, caprini and padua score to predict the risk of DVT. The study was at H. Adam Malik Hospital in Medan.From a total of 72 subjects, 39 people (54.2%) are men and the mean age are 53.14 years. Wells score, caprini score and padua score has a sensitivity of 80.6%; 61.1%, 50% respectively; specificity of 80.65; 66.7%; 75% respectively, and accuracy of 87.5%; 64.3%; 65.7% respectively.Wells score has better sensitivity, specificity and accuracy than caprini and padua score in diagnosing DVT.

Quality of sleep and health-related quality of life in renal transplant recipients.

Science.gov (United States)

Liu, Hong-Xia; Lin, Jun; Lin, Xiao-Hong; Wallace, Linda; Teng, Sha; Zhang, Shu-Ping; Hao, Yu-Fang

2015-01-01

The purpose of this study was to examine the sleep quality and health-related quality of life (HRQOL) in patients after renal transplantation and to explore the relationship between the quality of sleep and the HRQOL. Sleep disorders are still an important clinical problem after renal transplantation. Previous studies mainly focused on patients' sleep quality before kidney transplant. More studies are needed to document sleep quality after renal transplantation. A cross-sectional design was used in this study. A convenience sample of renal transplant recipients was recruited at an outpatient transplant clinic of a general hospital in Beijing, China. The Pittsburgh Sleep Quality Index (PSQI) was used to measure quality of sleep. The Medical Outcomes Study 36-item Short Form (MOS SF-36) was used to measure health-related quality of life. The average PSQI score of the 204 renal transplant recipients was 5.81±3.52, significantly lower than the norm. Fifty (24.5%) recipients were classified as having poor sleep quality (global PSQI > 7). The mean scores of renal transplant recipients for SF-36 Mental Component Summary (MCS) and Physical Component Summary (PCS) were 47.57±6.71 and 48.26±9.66 respectively. Compared with residents in Sichuan province, recipients' scores for SF-36 dimensions were statistically lower except the dimension of mental health. SF-36 scores of poor sleepers (PSQI > 7) were significantly lower than the good sleepers (PSQI ≤ 7) in both the MCS and PCS. Significant differences exist between the groups in physical function, bodily pain, vitality, and mental health dimensions. Sleep quality and HRQOL of patients after renal transplantation were lower than the norm. Poor sleep is associated with lower HRQOL. Health professionals need to pay attention to sleep quality and HRQOL in renal transplant recipients and take appropriate measures to improve patients' sleep quality and HRQOL.

Phonocatalysis. An ab initio simulation experiment

Directory of Open Access Journals (Sweden)

Kwangnam Kim

2016-06-01

Full Text Available Using simulations, we postulate and show that heterocatalysis on large-bandgap semiconductors can be controlled by substrate phonons, i.e., phonocatalysis. With ab initio calculations, including molecular dynamic simulations, the chemisorbed dissociation of XeF6 on h-BN surface leads to formation of XeF4 and two surface F/h-BN bonds. The reaction pathway and energies are evaluated, and the sorption and reaction emitted/absorbed phonons are identified through spectral analysis of the surface atomic motion. Due to large bandgap, the atomic vibration (phonon energy transfer channels dominate and among them is the match between the F/h-BN covalent bond stretching and the optical phonons. We show that the chemisorbed dissociation (the pathway activation ascent requires absorption of large-energy optical phonons. Then using progressively heavier isotopes of B and N atoms, we show that limiting these high-energy optical phonons inhibits the chemisorbed dissociation, i.e., controllable phonocatalysis.

Efficient Ab-Initio Electron Transport Calculations for Heterostructures by the Nonequilibrium Green’s Function Method

Directory of Open Access Journals (Sweden)

Hirokazu Takaki

2014-01-01

Full Text Available We present an efficient computation technique for ab-initio electron transport calculations based on density functional theory and the nonequilibrium Green’s function formalism for application to heterostructures with two-dimensional (2D interfaces. The computational load for constructing the Green’s functions, which depends not only on the energy but also on the 2D Bloch wave vector along the interfaces and is thus catastrophically heavy, is circumvented by parallel computational techniques with the message passing interface, which divides the calculations of the Green’s functions with respect to energy and wave vectors. To demonstrate the computational efficiency of the present code, we perform ab-initio electron transport calculations of Al(100-Si(100-Al(100 heterostructures, one of the most typical metal-semiconductor-metal systems, and show their transmission spectra, density of states (DOSs, and dependence on the thickness of the Si layers.

Specific interactions between DNA and regulatory protein controlled by ligand-binding: Ab initio molecular simulation

Energy Technology Data Exchange (ETDEWEB)

Matsushita, Y., E-mail: kurita@cs.tut.ac.jp; Murakawa, T., E-mail: kurita@cs.tut.ac.jp; Shimamura, K., E-mail: kurita@cs.tut.ac.jp; Oishi, M., E-mail: kurita@cs.tut.ac.jp; Ohyama, T., E-mail: kurita@cs.tut.ac.jp; Kurita, N., E-mail: kurita@cs.tut.ac.jp [Department of Computer Science and Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi, 441-8580 (Japan)

2015-02-27

The catabolite activator protein (CAP) is one of the regulatory proteins controlling the transcription mechanism of gene. Biochemical experiments elucidated that the complex of CAP with cyclic AMP (cAMP) is indispensable for controlling the mechanism, while previous molecular simulations for the monomer of CAP+cAMP complex revealed the specific interactions between CAP and cAMP. However, the effect of cAMP-binding to CAP on the specific interactions between CAP and DNA is not elucidated at atomic and electronic levels. We here considered the ternary complex of CAP, cAMP and DNA in solvating water molecules and investigated the specific interactions between them at atomic and electronic levels using ab initio molecular simulations based on classical molecular dynamics and ab initio fragment molecular orbital methods. The results highlight the important amino acid residues of CAP for the interactions between CAP and cAMP and between CAP and DNA.

Specific interactions between DNA and regulatory protein controlled by ligand-binding: Ab initio molecular simulation

International Nuclear Information System (INIS)

Matsushita, Y.; Murakawa, T.; Shimamura, K.; Oishi, M.; Ohyama, T.; Kurita, N.

2015-01-01

The catabolite activator protein (CAP) is one of the regulatory proteins controlling the transcription mechanism of gene. Biochemical experiments elucidated that the complex of CAP with cyclic AMP (cAMP) is indispensable for controlling the mechanism, while previous molecular simulations for the monomer of CAP+cAMP complex revealed the specific interactions between CAP and cAMP. However, the effect of cAMP-binding to CAP on the specific interactions between CAP and DNA is not elucidated at atomic and electronic levels. We here considered the ternary complex of CAP, cAMP and DNA in solvating water molecules and investigated the specific interactions between them at atomic and electronic levels using ab initio molecular simulations based on classical molecular dynamics and ab initio fragment molecular orbital methods. The results highlight the important amino acid residues of CAP for the interactions between CAP and cAMP and between CAP and DNA

Can facial uniqueness be inferred from impostor scores?

NARCIS (Netherlands)

Dutta, A.; Veldhuis, Raymond N.J.; Spreeuwers, Lieuwe Jan

2013-01-01

In Biometrics, facial uniqueness is commonly inferred from impostor similarity scores. In this paper, we show that such uniqueness measures are highly unstable in the presence of image quality variations like pose, noise and blur. We also experimentally demonstrate the instability of a recently

Are Low Patient Satisfaction Scores Always Due to the Provider?: Determinants of Patient Satisfaction Scores During Spine Clinic Visits.

Science.gov (United States)

Bible, Jesse E; Shau, David N; Kay, Harrison F; Cheng, Joseph S; Aaronson, Oran S; Devin, Clinton J

2018-01-01

A prospective study. The aim of this study was to investigate the impact of various components on patient satisfaction scores SUMMARY OF BACKGROUND DATA.: Patient satisfaction has become an important component of quality assessments. However, with many of these sources collecting satisfaction data reluctant to disclose detailed information, little remains known about the potential determinants of patient satisfaction. Two hundred patients were contacted via phone within 3 weeks of new patient encounter with 11 spine providers. Standardized patient satisfaction phone survey consisting of 25 questions (1-10 rating scale) was administered. Questions inquired about scheduling, parking, office staff, teamwork, wait-time, radiology, provider interactions/behavior, treatment, and follow-up communication. Potential associations between these factors and three main outcome measures were investigated: (1) provider satisfaction, (2) overall clinic visit satisfaction, and (3) quality of care. Significant associations (P  0.05).In multivariate regression analysis, explanation of medical condition/treatment (P = 0.002) and provider empathy (P = 0.04) were significantly associated with provider satisfaction scores, while the amount of time spent with the provider was not. Conversely, teamwork of staff/provider and follow-up communication were significantly associated with both overall clinic visit satisfaction and quality of care (P ≤ 0.03), while provider behaviors or satisfaction were not. Satisfaction with the provider was associated with better explanations of the spine condition/treatment plan and provider empathy, but was not a significant factor in either overall clinic visit satisfaction or perceived quality of care. Patients' perception of teamwork between staff and providers along with reliable follow-up communication were found to be significant determinants of overall patient satisfaction and perceived quality of care. 3.

From empirical to ab initio: transferable potentials in the atomistic simulation of amorphous carbons

International Nuclear Information System (INIS)

Marks, N.A.; Goringe, C.M.; McKenzie, D.R.; McCulloch, D.G.; Royal Melbourne Institute of Technology University, Melbourne, VIC

2000-01-01

Full text: Silicon is often described as the prototype covalent material, and when it comes to developing atomistic models this situation is well described by the sentiment that 'everything works for silicon'. The same cannot be said for carbon though, where the interaction potential has always proved problematical, be it with empirical, tight-binding or ab initio methods. Thus far the most decisive contributions to understanding amorphous carbon networks have come from ab initio simulations using the Car-Parrinello method, where the fully quantum treatment of the valence electrons has provided unexpected insight into the local structure. However such first principles calculations are restricted spatially and temporally to systems with approximately 100 atoms and times of order one picosecond. There is therefore demand for less expensive techniques capable of resolving important questions whose solution can only to found with larger simulations running for longer times. In the case of tetrahedral amorphous carbon, such issues include the release of compressive stress through annealing, the origin of graphitic surface layers and the nature of the film growth process and thermal spike. Against this background tight-binding molecular dynamics has emerged as a popular alternative to first principles methods, and our group has an ongoing program to understand film growth using one of the efficient variants of tight-binding. Another direction of research is a new empirical potential based on the Environment Dependent Interaction Potential (EDIP) recently developed for silicon. The EDIP approach represents a promising direction for empirical potentials through its use of ab initio data to motivate the functional form as well as the more conventional parametrisation. By inverting ab initio cohesive energy curves the authors of EDIP arrived at a pair potential expression which reduces to the well-known Stillinger-Weber form at integer coordination, while providing

Histologic scoring indices for evaluation of disease activity in Crohn's disease.

Science.gov (United States)

Novak, Gregor; Parker, Claire E; Pai, Rish K; MacDonald, John K; Feagan, Brian G; Sandborn, William J; D'Haens, Geert; Jairath, Vipul; Khanna, Reena

2017-07-21

histological indices fulfilled the inclusion criteria.Inter-rater reliability was assessed in one study. For the Naini and Cortina Score, estimates of correlation were 'almost perfect', ranging from r = 0.94 to 0.96. The methodological quality of this study with respect to reliability was 'good'.With respect to validity, correlation estimates between various histological scoring systems and Crohn's disease activity as measured by objective markers of inflammation (including C-reactive protein, erythrocyte sedimentation rate, fecal calprotectin and fecal lactoferrin); endoscopic disease activity scores; clinical disease activity scores; and quality of life questionnaires were reported. Comparisons between histologic scoring indices and endoscopic scoring indices ranged from no correlation to 'substantial' (r = 0.779). The methodological quality of the studies that explored validity ranged form 'poor' to 'good'.Responsiveness data were available in seven studies. After subjects were administered a treatment of known efficacy, statistically significant change in the index score was demonstrated in five studies with respect to six indices. Two studies failed to indicate whether there was statistically significant change in the index score post-treatment. With regard to methodological quality, six of the studies were rated as 'poor' and one of the studies was rated as 'fair'.Feasibility was assessed by one study. The Naini and Cortina Score was shown to be simple to use and feasible for every given case. Currently there is no fully validated histological scoring index for evaluation of Crohn's disease activity. Development of a validated histological scoring index for Crohn's disease is a clinical and research priority.

Ab initio Defect Energetics in LaBO3 Perovskite Solid Oxide Fuel Cell Materials

DEFF Research Database (Denmark)

Lee, Yueh-Lin; Morgan, Dane; Kleis, Jesper

2009-01-01

Perovskite materials of the form ABO3 are a promising family of compounds for use in solid oxide fuel cell (SOFC) cathodes. Study of the physics of these compounds under SOFC conditions with ab initio methods is particularly challenging due to high temperatures, exchange of oxygen with O2 gas...

Mirnacle: machine learning with SMOTE and random forest for improving selectivity in pre-miRNA ab initio prediction.

Science.gov (United States)

Marques, Yuri Bento; de Paiva Oliveira, Alcione; Ribeiro Vasconcelos, Ana Tereza; Cerqueira, Fabio Ribeiro

2016-12-15

MicroRNAs (miRNAs) are key gene expression regulators in plants and animals. Therefore, miRNAs are involved in several biological processes, making the study of these molecules one of the most relevant topics of molecular biology nowadays. However, characterizing miRNAs in vivo is still a complex task. As a consequence, in silico methods have been developed to predict miRNA loci. A common ab initio strategy to find miRNAs in genomic data is to search for sequences that can fold into the typical hairpin structure of miRNA precursors (pre-miRNAs). The current ab initio approaches, however, have selectivity issues, i.e., a high number of false positives is reported, which can lead to laborious and costly attempts to provide biological validation. This study presents an extension of the ab initio method miRNAFold, with the aim of improving selectivity through machine learning techniques, namely, random forest combined with the SMOTE procedure that copes with imbalance datasets. By comparing our method, termed Mirnacle, with other important approaches in the literature, we demonstrate that Mirnacle substantially improves selectivity without compromising sensitivity. For the three datasets used in our experiments, our method achieved at least 97% of sensitivity and could deliver a two-fold, 20-fold, and 6-fold increase in selectivity, respectively, compared with the best results of current computational tools. The extension of miRNAFold by the introduction of machine learning techniques, significantly increases selectivity in pre-miRNA ab initio prediction, which optimally contributes to advanced studies on miRNAs, as the need of biological validations is diminished. Hopefully, new research, such as studies of severe diseases caused by miRNA malfunction, will benefit from the proposed computational tool.

Tailoring magnetoresistance at the atomic level: An ab initio study

KAUST Repository

Tao, Kun; Stepanyuk, V. S.; Rungger, I.; Sanvito, S.

2012-01-01

The possibility of manipulating the tunneling magnetoresistance (TMR) of antiferromagnetic nanostructures is predicted in the framework of ab initio calculations. By the example of a junction composed of an antiferromagnetic dimer and a spin-polarized scanning tunneling microscopy tip we show that the TMR can be tuned and even reversed in sign by lateral and vertical movements of the tip. Moreover, our finite-bias calculations demonstrate that the magnitude and the sign of the TMR can also be tuned by an external voltage. © 2012 American Physical Society.

Tailoring magnetoresistance at the atomic level: An ab initio study

KAUST Repository

Tao, Kun

2012-01-05

The possibility of manipulating the tunneling magnetoresistance (TMR) of antiferromagnetic nanostructures is predicted in the framework of ab initio calculations. By the example of a junction composed of an antiferromagnetic dimer and a spin-polarized scanning tunneling microscopy tip we show that the TMR can be tuned and even reversed in sign by lateral and vertical movements of the tip. Moreover, our finite-bias calculations demonstrate that the magnitude and the sign of the TMR can also be tuned by an external voltage. © 2012 American Physical Society.

Sleep Quality and Health-Related Quality of Life in Pregnancy.

Science.gov (United States)

Sut, Hatice Kahyaoglu; Asci, Ozlem; Topac, Nalan

The aim of this study was to investigate sleep quality and health-related quality of life in pregnancy. In a cross-sectional design, 492 women (292 pregnant and 200 nonpregnant healthy controls) were included in this study between November 2014 and June 2015. Participants completed a survey on sociodemographic characteristics, the Pittsburgh Sleep Quality Index (PSQI), and the European Quality of Life-5 Dimensions (EQ-5D). The PSQI total and EQ-5D scores of pregnant women were significantly worse than the controls (P = .017 and P sleep quality increased 2.11-fold in the second trimester (P = .048) and 1.86-fold in the third trimester (P = .054). Compared with the first trimester, EQ-5D scores significantly decreased in the second (P = .038) and third (P Sleep quality and health-related quality of life of pregnant women were worse than those of nonpregnant healthy controls. Healthcare professionals need to be aware of deteriorations in sleep quality and health-related quality of life of pregnant women.

Ductility improvement of Mg alloys by solid solution: Ab initio modeling, synthesis and mechanical properties

Czech Academy of Sciences Publication Activity Database

Sandlöbes, S.; Pei, Z.; Friák, Martin; Zhu, L.-F.; Wang, F.; Zaefferer, S.; Raabe, D.; Neugebauer, J.

2014-01-01

Roč. 70, MAY (2014), s. 92-104 ISSN 1359-6454 Grant - others:GA MŠk(CZ) LM2010005 Institutional support: RVO:68081723 Keywords : Magnesium * Rare-earth elements * Ductility * Modeling * Ab initio Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.465, year: 2014

Ab initio calculation of positron distribution, ACAR and lifetime in TTF-TCNQ

International Nuclear Information System (INIS)

Ishibashi, Shoji; Kohyama, Masanori

2000-01-01

We have performed ab initio calculations of positron distribution, ACAR and lifetime in the quasi-one-dimensional organic conductor TTF-TCNQ. The electronic structure is obtained within the LDA, while the positron state is calculated either with the LDA or with the GGA. Except the positron lifetime, differences between the LDA and GGA results are rather small. The obtained results are compared with our previous experiments and calculations.

H3+: Ab initio calculation of the vibration spectrum

International Nuclear Information System (INIS)

Carney, G.D.; Porter, R.N.

1976-01-01

The vibration spectrum of H 3 + is calculated from the representation of a previously reported [J. Chem Phys. 60, 4251 (1974)] ab initio potential-energy surface in a fifth degree Simons--Parr--Finlan (SPF) expansion. Morse- and harmonic-oscillator basis functions are used to describe the motions of the three oscillators and the Harris--Engerholm--Gwinn quadrature technique is used to obtain matrix elements of the Hamiltonian in the basis of vibrational configurations. Our variational method is thus analogous to configuration--interaction calculations for electronic states. The ground state is found to have a zero-point energy of 4345 cm -1 and a vibrationally averaged geometry of R 1 =R 2 =0.91396 A, theta=60.0012degree, where theta is the angle between the two equivalent bonds. The transition frequencies for the E and A 1 fundamentals are nu-bar/sub E/=2516 cm -1 and nu-bar/sub A/=3185 cm -1 and those for the corresponding first overtones of the bending mode are 2nu-bar/sub E/=5004 +- 4 cm -1 and 2nu-bar/sub A/=4799 cm -1 . The first overtone of the breathing mode is 6264 cm -1 . The first-excited A 1 vibration state is metastable with a dipole--radiation lifetime of 3 sec. Transition frequencies, Einstein coefficients, and lifetimes are reported for a total of 21 transitions. Analysis of results for Dunham number and normal-coordinate expansions in comparison with those for SPF expansion show the latter to be superior for ab initio vibrational calculations. A scheme for possible direct measurement of the fundamental A 1 and E vibrational bands is suggested

Theoretical study of silicon carbide under irradiation at the nano scale: classical and ab initio modelling

International Nuclear Information System (INIS)

Lucas, G.

2006-10-01

The behaviour of silicon carbide under irradiation has been studied using classical and ab initio simulations, focusing on the nano scale elementary processes. First, we have been interested in the calculation of threshold displacement energies, which are difficult to determine both experimentally and theoretically, and also the associated Frenkel pairs. In the framework of this thesis, we have carried out simulations in classical and ab initio molecular dynamics. For the classical approach, two types of potentials have been used: the Tersoff potential, which led to non satisfactory results, and a new one which has been developed during this thesis. This potential allows a better modelling of SiC under irradiation than most of the empirical potentials available for SiC. It is based on the EDIP potential, initially developed to describe defects in silicon, that we have generalized to SiC. For the ab initio approach, the feasibility of the calculations has been validated and average energies of 19 eV for the C and 38 eV for the Si sublattices have been determined, close to the values empirically used in the fusion community. The results obtained with the new potential EDIP are globally in agreement with those values. Finally, the elementary processes involved in the crystal recovery have been studied by calculating the stability of the created Frenkel pairs and determining possible recombination mechanisms with the nudged elastic band method. (author)

Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions

International Nuclear Information System (INIS)

Wang, Yimin; Bowman, Joel M.; Kamarchik, Eugene

2016-01-01

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na + H 2 O, F − H 2 O, and Cl − H 2 O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H 2 O potentials are permutationally invariant fits to roughly 20 000 coupled cluster CCSD(T) energies (awCVTZ basis for Na + and aVTZ basis for Cl − and F − ), over a large range of distances and H 2 O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.

Efficacy of the SU(3) scheme for ab initio large-scale calculations beyond the lightest nuclei

Energy Technology Data Exchange (ETDEWEB)

Dytrych, T. [Academy of Sciences of the Czech Republic (ASCR), Prague (Czech Republic); Louisiana State Univ., Baton Rouge, LA (United States); Maris, Pieter [Iowa State Univ., Ames, IA (United States); Launey, K. D. [Louisiana State Univ., Baton Rouge, LA (United States); Draayer, J. P. [Louisiana State Univ., Baton Rouge, LA (United States); Vary, James [Iowa State Univ., Ames, IA (United States); Langr, D. [Czech Technical Univ., Prague (Czech Republic); Aerospace Research and Test Establishment, Prague (Czech Republic); Saule, E. [Univ. of North Carolina, Charlotte, NC (United States); Caprio, M. A. [Univ. of Notre Dame, IN (United States); Catalyurek, U. [The Ohio State Univ., Columbus, OH (United States). Dept. of Electrical and Computer Engineering; Sosonkina, M. [Old Dominion Univ., Norfolk, VA (United States)

2016-06-09

We report on the computational characteristics of ab initio nuclear structure calculations in a symmetry-adapted no-core shell model (SA-NCSM) framework. We examine the computational complexity of the current implementation of the SA-NCSM approach, dubbed LSU3shell, by analyzing ab initio results for ⁶Li and ¹²C in large harmonic oscillator model spaces and SU(3)-selected subspaces. We demonstrate LSU3shell's strong-scaling properties achieved with highly-parallel methods for computing the many-body matrix elements. Results compare favorably with complete model space calculations and signi cant memory savings are achieved in physically important applications. In particular, a well-chosen symmetry-adapted basis a ords memory savings in calculations of states with a fixed total angular momentum in large model spaces while exactly preserving translational invariance.

Advances and applications in the FIREBALL ab initio tight-binding molecular-dynamics formalism

Czech Academy of Sciences Publication Activity Database

Lewis, J.P.; Jelínek, Pavel; Ortega, J.; Demkov, A.A.; Trabada, D.G.; Haycock, B.; Wang, H.; Adams, G.; Tomfohr, J.K.; Abad, E.; Wang, Ho.; Drabold, D.A.

2011-01-01

Roč. 248, č. 9 (2011), 1989-2007 ISSN 0370-1972 R&D Projects: GA ČR GA202/09/0545; GA ČR GAP204/10/0952 Grant - others:AVČR(CZ) M100100904 Institutional research plan: CEZ:AV0Z10100521 Keywords : DFT * ab initio molecular-dynamics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.316, year: 2011

Cooperative effects in spherical spasers: Ab initio analytical model

Science.gov (United States)

Bordo, V. G.

2017-06-01

A fully analytical semiclassical theory of cooperative optical processes which occur in an ensemble of molecules embedded in a spherical core-shell nanoparticle is developed from first principles. Both the plasmonic Dicke effect and spaser generation are investigated for the designs in which a shell/core contains an arbitrarily large number of active molecules in the vicinity of a metallic core/shell. An essential aspect of the theory is an ab initio account of the feedback from the core/shell boundaries which significantly modifies the molecular dynamics. The theory provides rigorous, albeit simple and physically transparent, criteria for both plasmonic superradiance and surface plasmon generation.

Assessment of calcium scoring performance in cardiac computed tomography

International Nuclear Information System (INIS)

Ulzheimer, Stefan; Kalender, Willi A.

2003-01-01

Electron beam tomography (EBT) has been used for cardiac diagnosis and the quantitative assessment of coronary calcium since the late 1980s. The introduction of mechanical multi-slice spiral CT (MSCT) scanners with shorter rotation times opened new possibilities of cardiac imaging with conventional CT scanners. The purpose of this work was to qualitatively and quantitatively evaluate the performance for EBT and MSCT for the task of coronary artery calcium imaging as a function of acquisition protocol, heart rate, spiral reconstruction algorithm (where applicable) and calcium scoring method. A cardiac CT semi-anthropomorphic phantom was designed and manufactured for the investigation of all relevant image quality parameters in cardiac CT. This phantom includes various test objects, some of which can be moved within the anthropomorphic phantom in a manner that mimics realistic heart motion. These tools were used to qualitatively and quantitatively demonstrate the accuracy of coronary calcium imaging using typical protocols for an electron beam (Evolution C-150XP, Imatron, South San Francisco, Calif.) and a 0.5-s four-slice spiral CT scanner (Sensation 4, Siemens, Erlangen, Germany). A special focus was put on the method of quantifying coronary calcium, and three scoring systems were evaluated (Agatston, volume, and mass scoring). Good reproducibility in coronary calcium scoring is always the result of a combination of high temporal and spatial resolution; consequently, thin-slice protocols in combination with retrospective gating on MSCT scanners yielded the best results. The Agatston score was found to be the least reproducible scoring method. The hydroxyapatite mass, being better reproducible and comparable on different scanners and being a physical quantitative measure, appears to be the method of choice for future clinical studies. The hydroxyapatite mass is highly correlated to the Agatston score. The introduced phantoms can be used to quantitatively assess the

Ab initio calculation of the electronic spectrum of azobenzene dyes and its impact on the design of optical data storage materials

DEFF Research Database (Denmark)

Åstrand, Per-Olof; Ramanujam, P.S.; Hvilsted, Søren

2000-01-01

Electronic excitation energies of 16 azobenzene dyes have been calculated by ab initio methods within the second-order polarization propagator approximation (SOPPA). Good agreement with expriment is found for the lowest singlet and triplet states for both the trans- and cis-azobenzene molecules......, the experimental singlet π → π* transitions are reproduced for a set of azobenzene dyes with different electron donor and acceptor groups and the correct shifts in excitation energy are obtained for the different substituents. It has also been demonstrated that ab initio methods can be used to determine suitable...

The use of the SF-36 questionnaire in adult survivors of childhood cancer: evaluation of data quality, score reliability, and scaling assumptions

Directory of Open Access Journals (Sweden)

Winter David L

2006-10-01

Full Text Available Abstract Background The SF-36 has been used in a number of previous studies that have investigated the health status of childhood cancer survivors, but it never has been evaluated regarding data quality, scaling assumptions, and reliability in this population. As health status among childhood cancer survivors is being increasingly investigated, it is important that the measurement instruments are reliable, validated and appropriate for use in this population. The aim of this paper was to determine whether the SF-36 questionnaire is a valid and reliable instrument in assessing self-perceived health status of adult survivors of childhood cancer. Methods We examined the SF-36 to see how it performed with respect to (1 data completeness, (2 distribution of the scale scores, (3 item-internal consistency, (4 item-discriminant validity, (5 internal consistency, and (6 scaling assumptions. For this investigation we used SF-36 data from a population-based study of 10,189 adult survivors of childhood cancer. Results Overall, missing values ranged per item from 0.5 to 2.9 percent. Ceiling effects were found to be highest in the role limitation-physical (76.7% and role limitation-emotional (76.5% scales. All correlations between items and their hypothesised scales exceeded the suggested standard of 0.40 for satisfactory item-consistency. Across all scales, the Cronbach's alpha coefficient of reliability was found to be higher than the suggested value of 0.70. Consistent across all cancer groups, the physical health related scale scores correlated strongly with the Physical Component Summary (PCS scale scores and weakly with the Mental Component Summary (MCS scale scores. Also, the mental health and role limitation-emotional scales correlated strongly with the MCS scale score and weakly with the PCS scale score. Moderate to strong correlations with both summary scores were found for the general health perception, energy/vitality, and social functioning

Hydrogen atom injection into carbon surfaces by comparison between Monte-Carlo, molecular dynamics and ab-initio calculations

International Nuclear Information System (INIS)

Ito, A.; Kenmotsu, T.; Kikuhara, Y.; Inai, K.; Ohya, K.; Wang, Y.; Irle, S.; Morokuma, K.; Nakamura, H.

2009-01-01

Full text: To understand the plasma-wall interaction on divertor plates, we investigate the interaction of hydrogen atoms and carbon materials used in the high heat flux components by the use of the following simulations. Monte-Carlo (MC) method based on binary collision approximation can calculate the sputtering process of hydrogen atoms on the carbon material quickly. Classical molecular dynamics (MD) method employs multi-body potential models and can treat realistic structures of crystal and molecule. The ab-initio method can calculate electron energy in quantum mechanics, which is regarded as realistic potential for atoms. In the present paper, the interaction of the hydrogen and the carbon material is investigated using the multi-scale (MC, MD and ab-initio) methods. The bombardment of hydrogen atoms onto the carbon material is simulated by the ACAT-code of the MC method, which cannot represent the structure of crystal, and the MD method using modified reactive empirical bond order (REBO) potential, which treats single crystal graphite and amorphous carbon. Consequently, we clarify that the sputtering yield and the reflection rate calculated by the ACAT-code agree with those on the amorphous carbon calculated by the MD. Moreover, there are many kinds of REBO potential for the MD. Adsorption, reflection and penetration rates between a hydrogen atom and a graphene surface are calculated by the MD simulations using the two kinds of potential model. For the incident energy of less than 1 eV, the MD simulation using the modified REBO potential, which is based on Brenner's REBO potential in 2002, shows that reflection is dominant, while the most popular Brenner's REBO potential in 1990 shows that adsorption is dominant. This reflection of the low energy injection is caused by a small potential barrier for the hydrogen atom in the modified REBO potential. The small potential barrier is confirmed by the ab-initio calculations, which are hybrid DFT (B3LYP/cc-pVDZ), ab-initio

Exploring relationships between hospital patient safety culture and Consumer Reports safety scores.

Science.gov (United States)

Smith, Scott Alan; Yount, Naomi; Sorra, Joann

2017-02-16

A number of private and public companies calculate and publish proprietary hospital patient safety scores based on publicly available quality measures initially reported by the U.S. federal government. This study examines whether patient safety culture perceptions of U.S. hospital staff in a large national survey are related to publicly reported patient safety ratings of hospitals. The Agency for Healthcare Research and Quality Hospital Survey on Patient Safety Culture (Hospital SOPS) assesses provider and staff perceptions of hospital patient safety culture. Consumer Reports (CR), a U.S. based non-profit organization, calculates and shares with its subscribers a Hospital Safety Score calculated annually from patient experience survey data and outcomes data gathered from federal databases. Linking data collected during similar time periods, we analyzed relationships between staff perceptions of patient safety culture composites and the CR Hospital Safety Score and its five components using multiple multivariate linear regressions. We analyzed data from 164 hospitals, with patient safety culture survey responses from 140,316 providers and staff, with an average of 856 completed surveys per hospital and an average response rate per hospital of 56%. Higher overall Hospital SOPS composite average scores were significantly associated with higher overall CR Hospital Safety Scores (β = 0.24, p Consumer Reports Hospital Safety Score, which is a composite of patient experience and outcomes data from federal databases. As hospital managers allocate resources to improve patient safety culture within their organizations, their efforts may also indirectly improve consumer-focused, publicly reported hospital rating scores like the Consumer Reports Hospital Safety Score.

Vibrational inelastic and charge transfer processes in H++H2 system: An ab initio study

Science.gov (United States)

Amaran, Saieswari; Kumar, Sanjay

2007-12-01

State-resolved differential cross sections, total and integral cross sections, average vibrational energy transfer, and the relative probabilities are computed for the H++H2 system using the newly obtained ab initio potential energy surfaces at the full CI/cc-pVQZ level of accuracy which allow for both the direct vibrational inelastic and the charge transfer processes. The quantum dynamics is treated within the vibrational close-coupling infinite-order-sudden approximation approach using the two ab initio quasidiabatic potential energy surfaces. The computed collision attributes for both the processes are compared with the available state-to-state scattering experiments at Ec.m.=20eV. The results are in overall good agreement with most of the observed scattering features such as rainbow positions, integral cross sections, and relative vibrational energy transfers. A comparison with the earlier theoretical study carried out on the semiempirical surfaces (diatomics in molecules) is also made to illustrate the reliability of the potential energy surfaces used in the present work.

The onset of ion solvation by ab initio calculations: Comparison of water and methanol

Czech Academy of Sciences Publication Activity Database

Pluhařová, Eva; Jungwirth, Pavel

2008-01-01

Roč. 73, 6/7 (2008), s. 733-744 ISSN 0010-0765 R&D Projects: GA MŠk LC512; GA ČR GA203/07/1006 Institutional research plan: CEZ:AV0Z40550506 Keywords : ions * water cluster * methanol * ab initio calculations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.784, year: 2008

Ab initio study on electron excitation and electron transfer in tryptophan-tyrosine system

International Nuclear Information System (INIS)

Tong Jing; Li Xiangyuan

2002-01-01

In this article, ab initio calculation has been performed to evaluate the transition energy of electronic excitation in tryptophan and tyrosine by using semiempirical molecular orbital method AM1 and complete active space self-consistent field method. The solvent effect has been considered by means of the conductor-like screening model. After geometric optimizations of isolated tryptophan and tyrosine, and their corresponding radicals and cations, reaction heat of these electron transfer reactions have been obtained by the means of complete active space self-consistent field method. The transition energies from the ground state, respectively, to the lowest excited state and to the lowest triplet state of these two amino acids are also calculated and compared with the experimentally observed values. The ionization potential and electron affinity are also calculated for tryptophan and tyrosine employing Koopmans' theorem and ab initio calculation. Compared with the experimental measurements, the theoretical results are found satisfactory. Theoretical results give good explanations on the experimental phenomena that N 3 · can preferably oxide the side chain of tryptophan residue and then the electron transfer from tyrosine residue to tryptophan residue follows in peptides involving tryptophan and tyrosine

Ab initio study of hydrogen adsorption on benzenoid linkers in metal-organic framework materials

International Nuclear Information System (INIS)

Gao Yi; Zeng, X C

2007-01-01

We have computed the energies of adsorption of molecular hydrogen on a number of molecular linkers in metal-organic framework solid materials using density functional theory (DFT) and ab initio molecular orbital methods. We find that the hybrid B3LYP (Becke three-parameter Lee-Yang-Parr) DFT method gives a qualitatively incorrect prediction of the hydrogen binding with benzenoid molecular linkers. Both local-density approximation (LDA) and generalized gradient approximation (GGA) DFT methods are inaccurate in predicting the values of hydrogen binding energies, but can give a qualitatively correct prediction of the hydrogen binding. When compared to the more accurate binding-energy results based on the ab initio Moeller-Plesset second-order perturbation (MP2) method, the LDA results may be viewed as an upper limit while the GGA results may be viewed as a lower limit. Since the MP2 calculation is impractical for realistic metal-organic framework systems, the combined LDA and GGA calculations provide a cost-effective way to assess the hydrogen binding capability of these systems

Magnetism and metal insulator transition in FeSi and FeGe. Ab Initio investigations of the electronic structure; Magnetismus und Metall-Isolator-Uebergang in FeSi und FeGe. Ab-initio-Untersuchungen der elektronischen Struktur

Energy Technology Data Exchange (ETDEWEB)

Neef, Matthias

2007-03-19

Aim of this thesis was to reach by a systematic study of different ab initio procedures an improved description of the electronic properties of FeSi and FeGe. Central result is the itinerant description of FeSi as a semiconductor in the neighbourhood of a ferromagnetic instability. The regardment of the nonlocal exchange in the effective one-particle approximation leads to a metastable magnetic state scarcely above the magnetic ground state. The application of the hybrid functional leads to a 1st order metal-isolator transition for large lattice parameters: FeSi transforms at increasement of the lattice parameter from an unmagnetic isolator to a magnetic metal. A similar behavior is found in the isostructural compound FeGe. The two systems FeSi and FeGe were systematically and detailedly analyzed by means of ab initio procedures. Thereby the structural, electronic, and magnetic properties were studied with DFT and HF calculations. Both calculations with spin polarization and without spin polarization were performed.

Raman Spectroscopy and Ab-Initio Model Calculations on Ionic Liquids:Invited Review

OpenAIRE

Berg, Rolf W.

2007-01-01

A review of the recent developments in the study and understanding of room temperature ionic liquids are given. An intimate picture of how and why these liquids are not crystals at ambient conditions is attempted, based on evidence from crystallographical results combined with vibrational spectroscopy and ab-initio molecular orbital calculations. A discussion is given, based mainly on some recent FT-Raman spectroscopic results on the model ionic liquid system of 1-butyl-3-methylimidazolium ([...

Ab-initio electronic and magnetic properties of Fe-Al alloys

Directory of Open Access Journals (Sweden)

Apiñaniz, E.

2000-06-01

Full Text Available This work presents ab-initio self-consistent calculations performed with the TB-LMTO code to study the different phases of the Fe-Al phase diagram, corresponding to the ordered structures B2, DO3 and B32 and for Fe50Al50 and Fe3Al compositions. Both, unpolarized and spin-polarized calculations have been performed to deduce the energetic difference between the paramagnetic and ferromagnetic state of the corresponding structure. Calculations for the disordered structures have also been performed for the previously mentioned compositions. These results show that by disordering the alloy magnetism is enhanced and that the equilibrium lattice parameter increases.

En este trabajo se presentan cálculos autoconsistentes ab-initio realizados con el método TB-LMTO (Tight Binding Linear Muffin Tin Orbital con el fin de estudiar las diferentes estructuras que se presentan en el diagrama de fases de las aleaciones Fe-Al. Se han estudiado las estructuras ordenadas B2, DO3 y B32 para las siguientes concentraciones: Fe50Al50 y Fe3Al. Asimismo, se han realizado cálculos teniendo y sin tener en cuenta la polarización de spin con el fin de poder deducir la diferencia energética entre los estados ferromágneticos y paramágneticos de la misma estructura. Por otra parte se han realizado estos mismos cálculos para estructuras desordenadas y las mismas concentraciones. Los resultados muestran que mediante el desorden aumenta el magnetismo de estas aleaciones y crece el parámetro de red.

One Size Fits All? Learning Conditions and Working Memory Capacity in "Ab Initio" Language Development

Science.gov (United States)

Sanz, Cristina; Lin, Hui-Ju; Lado, Beatriz; Stafford, Catherine A.; Bowden, Harriet W.

2016-01-01

The article summarizes results from two experimental studies (N = 23, N = 21) investigating the extent to which working memory capacity (WMC) intervenes in "ab initio" language development under two pedagogical conditions [± grammar lesson + input-based practice + explicit feedback]. The linguistic target is the use of morphosyntax to…

Values for digestible indispensable amino acid scores (DIAAS) for some dairy and plant proteins may better describe protein quality than values calculated using the concept for protein digestibility-corrected amino acid scores (PDCAAS).

Science.gov (United States)

Mathai, John K; Liu, Yanhong; Stein, Hans H

2017-02-01

An experiment was conducted to compare values for digestible indispensable amino acid scores (DIAAS) for four animal proteins and four plant proteins with values calculated as recommended for protein digestibility-corrected amino acid scores (PDCAAS), but determined in pigs instead of in rats. Values for standardised total tract digestibility (STTD) of crude protein (CP) and standardised ileal digestibility (SID) of amino acids (AA) were calculated for whey protein isolate (WPI), whey protein concentrate (WPC), milk protein concentrate (MPC), skimmed milk powder (SMP), pea protein concentrate (PPC), soya protein isolate (SPI), soya flour and whole-grain wheat. The PDCAAS-like values were calculated using the STTD of CP to estimate AA digestibility and values for DIAAS were calculated from values for SID of AA. Results indicated that values for SID of most indispensable AA in WPI, WPC and MPC were greater (P<0·05) than for SMP, PPC, SPI, soya flour and wheat. With the exception of arginine and tryptophan, the SID of all indispensable AA in SPI was greater (P<0·05) than in soya flour, and with the exception of threonine, the SID of all indispensable AA in wheat was less (P<0·05) than in all other ingredients. If the same scoring pattern for children between 6 and 36 months was used to calculate PDCAAS-like values and DIAAS, PDCAAS-like values were greater (P<0·05) than DIAAS values for SMP, PPC, SPI, soya flour and wheat indicating that PDCAAS-like values estimated in pigs may overestimate the quality of these proteins.

Cost-Effective Method for Free-Energy Minimization in Complex Systems with Elaborated Ab Initio Potentials.

Science.gov (United States)

Bistafa, Carlos; Kitamura, Yukichi; Martins-Costa, Marilia T C; Nagaoka, Masataka; Ruiz-López, Manuel F

2018-05-22

We describe a method to locate stationary points in the free-energy hypersurface of complex molecular systems using high-level correlated ab initio potentials. In this work, we assume a combined QM/MM description of the system although generalization to full ab initio potentials or other theoretical schemes is straightforward. The free-energy gradient (FEG) is obtained as the mean force acting on relevant nuclei using a dual level strategy. First, a statistical simulation is carried out using an appropriate, low-level quantum mechanical force-field. Free-energy perturbation (FEP) theory is then used to obtain the free-energy derivatives for the target, high-level quantum mechanical force-field. We show that this composite FEG-FEP approach is able to reproduce the results of a standard free-energy minimization procedure with high accuracy, while simultaneously allowing for a drastic reduction of both computational and wall-clock time. The method has been applied to study the structure of the water molecule in liquid water at the QCISD/aug-cc-pVTZ level of theory, using the sampling from QM/MM molecular dynamics simulations at the B3LYP/6-311+G(d,p) level. The obtained values for the geometrical parameters and for the dipole moment of the water molecule are within the experimental error, and they also display an excellent agreement when compared to other theoretical estimations. The developed methodology represents therefore an important step toward the accurate determination of the mechanism, kinetics, and thermodynamic properties of processes in solution, in enzymes, and in other disordered chemical systems using state-of-the-art ab initio potentials.

Ab Initio Assessment of the Bonding in Disulfonates Containing Divalent Nitrogen and Phosphorus Atoms

DEFF Research Database (Denmark)

Andersen, Vinca Bonde; Berg, Rolf W.; Shim, Irene

2017-01-01

The iminodisulfonate, [N(SO3)2]3–, and phosphinodisulfonate, [P(SO3)2]3–, ions have been investigated by performing ab initio MP2/6-311+G**calculations. The nitrogen and phosphorus atoms as part of the ions are shown to be divalent with a negative charge and two lone pairs on the nitrogen...

The relationship between general practice characteristics and quality of care: a national survey of quality indicators used in the UK Quality and Outcomes Framework, 2004–5

Directory of Open Access Journals (Sweden)

Armstrong David

2006-11-01

Full Text Available Abstract Background The descriptive information now available for primary care in the UK is unique in international terms. Under the 'Quality and Outcomes Framework' (QOF, data for 147 performance indicators are available for each general practice. We aimed to determine the relationship between the quality of primary care, as judged by the total QOF score, social deprivation and practice characteristics. Methods We obtained QOF data for each practice in England and linked these with census derived data (deprivation indices and proportion of patients born in a developing country. Characteristics of practices were also obtained. QOF and census data were available for 8480 practices. Results The median QOF score was 999.7 out of a possible maximum of 1050 points. Three characteristics were independently associated with higher QOF scores: training practices, group practices and practices in less socially deprived areas. In a regression model, these three factors explained 14.6% of the variation in QOF score. Higher list sizes per GP, turnover of registered patients, chronic disease prevalence, proportions of elderly patients or patients born in a developing country did not contribute to lower QOF scores in the final model. Conclusion Socially deprived areas experience a lower quality of primary care, as judged by QOF scores. Social deprivation itself is an independent predictor of lower quality. Training and group practices are independent predictors of higher quality but these types of practices are less well represented in socially deprived areas.

Association between value-based purchasing score and hospital characteristics

Directory of Open Access Journals (Sweden)

Borah Bijan J

2012-12-01

Full Text Available Abstract Background Medicare hospital Value-based purchasing (VBP program that links Medicare payments to quality of care will become effective from 2013. It is unclear whether specific hospital characteristics are associated with a hospital’s VBP score, and consequently incentive payments. The objective of the study was to assess the association of hospital characteristics with (i the mean VBP score, and (ii specific percentiles of the VBP score distribution. The secondary objective was to quantify the associations of hospital characteristics with the VBP score components: clinical process of care (CPC score and patient satisfaction score. Methods Observational analysis that used data from three sources: Medicare Hospital Compare Database, American Hospital Association 2010 Annual Survey and Medicare Impact File. The final study sample included 2,491 U.S. acute care hospitals eligible for the VBP program. The association of hospital characteristics with the mean VBP score and specific VBP score percentiles were assessed by ordinary least square (OLS regression and quantile regression (QR, respectively. Results VBP score had substantial variations, with mean score of 30 and 60 in the first and fourth quartiles of the VBP score distribution. For-profit status (vs. non-profit, smaller bed size (vs. 100–199 beds, East South Central region (vs. New England region and the report of specific CPC measures (discharge instructions, timely provision of antibiotics and beta blockers, and serum glucose controls in cardiac surgery patients were positively associated with mean VBP scores (p Conclusions Although hospitals serving the poor and the elderly are more likely to score lower under the VBP program, the correlation appears small. Profit status, geographic regions, number and type of CPC measures reported explain the most variation among scores.

Ab initio molecular dynamics in a finite homogeneous electric field.

Science.gov (United States)

Umari, P; Pasquarello, Alfredo

2002-10-07

We treat homogeneous electric fields within density functional calculations with periodic boundary conditions. A nonlocal energy functional depending on the applied field is used within an ab initio molecular dynamics scheme. The reliability of the method is demonstrated in the case of bulk MgO for the Born effective charges, and the high- and low-frequency dielectric constants. We evaluate the static dielectric constant by performing a damped molecular dynamics in an electric field and avoiding the calculation of the dynamical matrix. Application of this method to vitreous silica shows good agreement with experiment and illustrates its potential for systems of large size.

Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions

Energy Technology Data Exchange (ETDEWEB)

Wang, Yimin, E-mail: yimin.wang@emory.edu; Bowman, Joel M., E-mail: jmbowma@emory.edu [Department of Chemistry, Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States); Kamarchik, Eugene, E-mail: eugene.kamarchik@gmail.com [Quantum Pomegranate, LLC, 2604 Kings Lake Court NE, Atlanta, Georgia 30345 (United States)

2016-03-21

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na{sup +}H{sub 2}O, F{sup −}H{sub 2}O, and Cl{sup −}H{sub 2}O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H{sub 2}O potentials are permutationally invariant fits to roughly 20 000 coupled cluster CCSD(T) energies (awCVTZ basis for Na{sup +} and aVTZ basis for Cl{sup −} and F{sup −}), over a large range of distances and H{sub 2}O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.

Protein quality and growth in malnourished children

DEFF Research Database (Denmark)

Manary, Mark; Callaghan, Meghan; Singh, Lauren

2016-01-01

BACKGROUND: Protein quality refers to the amounts and ratios of essential amino acids in a food. Two methods most commonly used for determining protein quality are the protein digestibility-corrected amino acid score (PDCAAS) and the digestible indispensible amino acid score (DIAAS). OBJECTIVE...... in children with SAM and acute infection, and these data were reviewed with respect to protein synthesis. Eleven published treatment trials for SAM with different therapeutic foods were analyzed to examine the relationship between protein quality scores with weight gain (g/kg/d). Protein scores were...... calculated with the PDCAAS and DIAAS amino acid reference patterns. A DIAAS score adjusted for the higher weight gain expected in malnourished children was also used. Bivariate correlation analysis was used to examine this relationship. RESULTS: The protein kinetic data supported the hypothesis...

The T2 phase in the Nb–Si–B system studied by ab initio calculations and synchrotron X-ray diffraction

International Nuclear Information System (INIS)

Joubert, J.-M.; Colinet, C.; Rodrigues, G.; Suzuki, P.A.; Nunes, C.A.; Coelho, G.C.; Tedenac, J.-C.

2012-01-01

The solid solution based on Nb 5 Si 3 (Cr 5 B 3 structure type, D8 l , tI32, I4/mcm, No140, a=6.5767 Å, c=11.8967 Å) in the Nb–Si–B system was studied from the structural and thermodynamic point of view both experimentally and by ab initio calculations. Rietveld refinement of powder X-ray synchrotron data allowed to determine the boron to silicon substitution mechanism and the structural parameters. Ab initio calculations of different ordered compounds and selected disordered alloys allowed to obtain in addition to the enthalpy of formation of the solution, substitution mechanism and structural parameters which are in excellent agreement with the experimental data. The stability of the phase is discussed. - Graphial abstract: Valence-charge electron localization function in the z=0 plane of the D8 l structure for the ordered compound Nb 5 SiB 2 . Highlights: ► Coupling between ab initio data and experimental results from synchrotron powder diffraction. ► Excellent agreement between the two techniques for the site occupancies and internal coordinates. ► Explanation of the phase stability up to Nb 5 SiB 2 .

Assessment of quality of prescribing in patients of hypertension at primary and secondary health care facilities using the Prescription Quality Index (PQI) tool.

Science.gov (United States)

Suthar, Jalpa Vashishth; Patel, Varsha J

2014-01-01

To determine the quality of prescribing in hypertension in primary and secondary health care settings using the Prescription Quality Index (PQI) tool and to assess the reliability of this tool. An observational cross-sectional study was carried out for 6 months in order to assess quality of prescribing of antihypertensive drugs using Prescription Quality Index (PQI) at four primary (PHC) and two secondary (SHC) health care facilities. Patients attending these facilities for at least 3 months were included. Complete medical history and prescriptions received were noted. Total and criteria wise PQI scores were derived for each prescription. Prescriptions were categorized as poor (score of ≤31), medium (score 32-33) and high quality (score 34-43) based on PQI total score. Psychometric analysis using factor analysis was carried out to assess reliability and validity. Total 73 hypertensive patients were included. Mean age was 61.2 ± 11 years with 35 (48%) patients above 65 years of age. Total PQI score was 26 ± 11. There was a significant difference in PQI score between PHC and SHC (P hypertensive patients was poor, somewhat better in primary as compared to secondary health care facility. PQI is reliable for measuring prescribing quality in hypertension in Indian set up.

Parent reports of health-related quality of life and heart failure severity score independently predict outcome in children with dilated cardiomyopathy.

Science.gov (United States)

den Boer, Susanna L; Baart, Sara J; van der Meulen, Marijke H; van Iperen, Gabriëlle G; Backx, Ad P; Ten Harkel, Arend D; Rammeloo, Lukas A; du Marchie Sarvaas, Gideon J; Tanke, Ronald B; Helbing, Willem A; Utens, Elisabeth M; Dalinghaus, Michiel

2017-08-01

Dilated cardiomyopathy in children causes heart failure and has a poor prognosis. Health-related quality of life in this patient group is unknown. Moreover, results may provide detailed information of parents' sense of their child's functioning. We hypothesised that health-related quality of life, as rated by parents, and the paediatric heart failure score, as assessed by physicians, have both predictive value on outcome. Methods and results In this prospective study, health-related quality of life was assessed by parent reports: the Infant Toddler Quality of Life questionnaire (0-4 years) or Child Health Questionnaire-Parent Form 50 (4-18 years) at 3-6-month intervals. We included 90 children (median age 3.8 years, interquartile range (IQR) 0.9-12.3) whose parents completed 515 questionnaires. At the same visit, physicians completed the New York University Pediatric Heart Failure Index. Compared with Dutch normative data, quality of life was severely impaired at diagnosis (0-4 years: 7/10 subscales and 4-18 years: 8/11 subscales) and ⩾1 year after diagnosis (3/10 and 6/11 subscales). Older children were more impaired (pFailure Index were independently predictive of the risk of death and heart transplantation (hazard ratio 1.24 per 10% decrease of predicted, 95% confidence interval (CI) 1.06-1.47 and hazard ratio 1.38 per unit, 95% CI 1.19-1.61, respectively). Physical impairment rated by parents and heart failure severity assessed by physicians independently predicted the risk of death or heart transplantation in children with dilated cardiomyopathy.

Estudo da geometria da uréia por métodos ab initio e simulação computacional de líquidos

OpenAIRE

Cirino,José Jair Vianna; Bertran,Celso Aparecido

2002-01-01

A study was carried out on the urea geometries using ab initio calculation and Monte Carlo computational simulation of liquids. The ab initio calculated results showed that urea has a non-planar conformation in the gas phase in which the hydrogen atoms are out of the plane formed by the heavy atoms. Free energies associated to the rotation of the amino groups of urea in water were obtained using the Monte Carlo method in which the thermodynamic perturbation theory is implemented. The magnitud...

Ab initio electronic structure and correlations in pristine and potassium-doped molecular crystals of copper phthalocyanine

NARCIS (Netherlands)

Giovannetti, G.; Brocks, G.; van den Brink, J.

2008-01-01

We investigate the effect that potassium intercalation has on the electronic structure of copper phthalocyanine (CuPc) molecular crystals by means of ab initio density functional calculations. Pristine CuPc (in its alpha and beta structures) is found to be an insulator containing local magnetic

Structural, dynamical, electronic, and bonding properties of laser-heated silicon: An ab initio molecular-dynamics study

NARCIS (Netherlands)

Silvestrelli, P.-L.; Alavi, A.; Parrinello, M.; Frenkel, D.

1997-01-01

The method of ab initio molecular dynamics, based on finite-temperature density-functional theory, is used to simulate laser heating of crystalline silicon. We found that a high concentration of excited electrons dramatically weakens the covalent bonding. As a result the system undergoes a melting

Quantitative verification of ab initio self-consistent laser theory.

Science.gov (United States)

Ge, Li; Tandy, Robert J; Stone, A D; Türeci, Hakan E

2008-10-13

We generalize and test the recent "ab initio" self-consistent (AISC) time-independent semiclassical laser theory. This self-consistent formalism generates all the stationary lasing properties in the multimode regime (frequencies, thresholds, internal and external fields, output power and emission pattern) from simple inputs: the dielectric function of the passive cavity, the atomic transition frequency, and the transverse relaxation time of the lasing transition.We find that the theory gives excellent quantitative agreement with full time-dependent simulations of the Maxwell-Bloch equations after it has been generalized to drop the slowly-varying envelope approximation. The theory is infinite order in the non-linear hole-burning interaction; the widely used third order approximation is shown to fail badly.

Raman spectroscopy, ab-initio model calculations, and conformational, equilibria in ionic liquids

OpenAIRE

Berg, Rolf W.

2009-01-01

A review of the recent developments in the study and understanding of room temperature ionic liquids are given. An intimate picture of how and why these liquids are not crystals at ambient conditions is attempted, based on evidence from crystallographical results combined with vibrational spectroscopy and ab-initio molecular orbital calculations. A discussion is given, based mainly on some recent FT- Raman spectroscopic results on the model ionic liquid system of 1-butyl-3-methyl-imidazolium ...

Study of carvedilol by combined Raman spectroscopy and ab initio MO calculations

OpenAIRE

Marques, M. P. M.; Oliveira, P. J.; Moreno, A. J. M.; Carvalho, L. A. E. Batista de

2002-01-01

The novel cardioprotective drug carvedilol was studied by both Raman spectroscopy and ab initio molecular orbital methods (using the density functional theory approach). The spectra, acquired both for the solid samples and DMSO solutions as a function of pH, were assigned in view of the calculated wavenumbers and intensities, and also based on the experimental data obtained for individual compounds which comprise the molecule, namely carbazole and 1,2-dimethoxybenzene. The pH dependence of th...

Ab Initio Analysis of Auger-Assisted Electron Transfer.

Science.gov (United States)

Hyeon-Deuk, Kim; Kim, Joonghan; Prezhdo, Oleg V

2015-01-15

Quantum confinement in nanoscale materials allows Auger-type electron-hole energy exchange. We show by direct time-domain atomistic simulation and analytic theory that Auger processes give rise to a new mechanism of charge transfer (CT) on the nanoscale. Auger-assisted CT eliminates the renown Marcus inverted regime, rationalizing recent experiments on CT from quantum dots to molecular adsorbates. The ab initio simulation reveals a complex interplay of the electron-hole and charge-phonon channels of energy exchange, demonstrating a variety of CT scenarios. The developed Marcus rate theory for Auger-assisted CT describes, without adjustable parameters, the experimental plateau of the CT rate in the region of large donor-acceptor energy gap. The analytic theory and atomistic insights apply broadly to charge and energy transfer in nanoscale systems.

Quality of web-based information on pathological gambling.

Science.gov (United States)

Khazaal, Yasser; Chatton, Anne; Cochand, Sophie; Jermann, Françoise; Osiek, Christian; Bondolfi, Guido; Zullino, Daniele

2008-09-01

The present study aims to evaluate the quality of web-based information on gambling and to investigate potential content quality indicators. The following key words: gambling, pathological gambling, excessive gambling, gambling problem and gambling addiction were entered into two popular search engines: Google and Yahoo. Websites were assessed with a standardized proforma designed to rate sites on the basis of "accountability", "presentation", "interactivity", "readability" and "content quality". "Health on the Net" (HON) quality label, and DISCERN scale scores aiding people without content expertise to assess quality of written health publication were used to verify their efficiency as quality indicators. Of the 200 links identified, 75 websites were included. The results of the study indicate low scores on each of the measures. A composite global score appeared as a good content quality indicator. While gambling-related education websites for patients are common, their global quality is poor. There is a need for useful evidence-based information about gambling on the web. As the phenomenon has greatly increased, it could be relevant for Internet sites to improve their content by using global score as a quality indicator.

[Quality management in a clinical research facility: Evaluation of changes in quality in-house figures and the appraisal of in-house quality indicators].

Science.gov (United States)

Aden, Bile; Allekotte, Silke; Mösges, Ralph

2016-12-01

For long-term maintenance and improvement of quality within a clinical research institute, the implementation and certification of a quality management system is suitable. Due to the implemented quality management system according to the still valid DIN EN ISO 9001:2008 desired quality objectives are achieved effectively. The evaluation of quality scores and the appraisal of in-house quality indicators make an important contribution in this regard. In order to achieve this and draw quality assurance conclusions, quality indicators as sensible and sensitive as possible are developed. For this, own key objectives, the retrospective evaluation of quality scores, a prospective follow-up and also discussions establish the basis. In the in-house clinical research institute the measures introduced by the quality management led to higher efficiency in work processes, improved staff skills, higher customer satisfaction and overall to more successful outcomes in relation to the self-defined key objectives. Copyright © 2016. Published by Elsevier GmbH.

Quality of Smartphone Apps Related to Alcohol Use Disorder.

Science.gov (United States)

Penzenstadler, Louise; Chatton, Anne; Van Singer, Mathias; Khazaal, Yasser

2016-01-01

Apps for smartphones are opening an important range of opportunities for improving the care of people with alcohol use disorders (AUDs). This study aimed to evaluate the quality of English language apps for AUDs and to compare paid and free apps. The keywords 'alcohol', 'alcohol addiction', 'alcohol help' and 'stop drinking' were entered into the iTunes Store search engine. Apps were evaluated using a standardized assessment designed to rate the quality of apps in terms of accountability, interactivity, self-help score and evidence-based content. The Brief DISCERN score and the criteria of the 'Health on the Net' label were also used as content quality indicators. Of the 137 unique apps identified, 52 met the inclusion criteria. Overall, the content quality and self-help scores of these AUD apps were poor. The main quality indicators were not linked to payment status. Multiple linear regressions showed that the Brief DISCERN score significantly predicted content quality. Poor content quality and self-help scores of AUD smartphone apps underline the gap between their potential promises and the overall quality of available products in stores. The quality indicators used in the present study may be used for further app developments. © 2016 S. Karger AG, Basel.

Scoring systems of severity in patients with multiple trauma.

Science.gov (United States)

Rapsang, Amy Grace; Shyam, Devajit Chowlek

2015-04-01

Trauma is a major cause of morbidity and mortality; hence severity scales are important adjuncts to trauma care in order to characterize the nature and extent of injury. Trauma scoring models can assist with triage and help in evaluation and prediction of prognosis in order to organise and improve trauma systems. Given the wide variety of scoring instruments available to assess the injured patient, it is imperative that the choice of the severity score accurately match the application. Even though trauma scores are not the key elements of trauma treatment, they are however, an essential part of improvement in triage decisions and in identifying patients with unexpected outcomes. This article provides the reader with a compendium of trauma severity scales along with their predicted death rate calculation, which can be adopted in order to improve decision making, trauma care, research and in comparative analyses in quality assessment. Copyright © 2013 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Atomic ionization of germanium by neutrinos from an ab initio approach

International Nuclear Information System (INIS)

Chen, Jiunn-Wei; Chi, Hsin-Chang; Huang, Keh-Ning; Liu, C.-P.; Shiao, Hao-Tse; Singh, Lakhwinder; Wong, Henry T.; Wu, Chih-Liang; Wu, Chih-Pan

2014-01-01

An ab initio calculation of atomic ionization of germanium by neutrinos was carried out in the framework of multiconfiguration relativistic random phase approximation and benchmarked by related atomic structure and photoabsorption data. This improves over the conventional approach based on scattering off free electrons whose validity at sub-keV energy transfer is questionable. Limits on neutrino magnetic moments are derived using reactor neutrino data taken with low threshold germanium detectors. Future applications of these atomic techniques will greatly reduce the atomic uncertainties in low-energy neutrino and dark matter detections.

Spin-orbit interaction effects in zincblende semiconductors: Ab initio pseudopotential calculations

International Nuclear Information System (INIS)

Li, Ming-Fu; Surh, M.P.; Louie, S.G.

1988-06-01

Ab initio band structure calculations have been performed for the spin-orbit interaction effects at the top of the valence bands for GaAs and InSb. Relativistic, norm-conserving pseudopotentials are used with no correction made for the gaps from the local density approximation. The spin-orbit splitting at Γ and linear terms in the /rvec char/k dependence of the splitting are found to be in excellent agreement with existing experiments and previous theoretical results. The effective mass and the cubic splitting terms are also examined. 6 refs., 1 fig., 2 tabs

Fingerprint Recognition Using Minutia Score Matching

OpenAIRE

J, Ravi.; Raja, K. B.; R, Venugopal. K.

2010-01-01

The popular Biometric used to authenticate a person is Fingerprint which is unique and permanent throughout a person’s life. A minutia matching is widely used for fingerprint recognition and can be classified as ridge ending and ridge bifurcation. In this paper we projected Fingerprint Recognition using Minutia Score Matching method (FRMSM). For Fingerprint thinning, the Block Filter is used, which scans the image at the boundary to preserves the quality of the image and extract the minutiae ...

MODELING CREDIT RISK THROUGH CREDIT SCORING

OpenAIRE

Adrian Cantemir CALIN; Oana Cristina POPOVICI

2014-01-01

Credit risk governs all financial transactions and it is defined as the risk of suffering a loss due to certain shifts in the credit quality of a counterpart. Credit risk literature gravitates around two main modeling approaches: the structural approach and the reduced form approach. In addition to these perspectives, credit risk assessment has been conducted through a series of techniques such as credit scoring models, which form the traditional approach. This paper examines the evolution of...

Ab initio study of antiphase boundaries and stacking faults in L12 and DO22 compounds

DEFF Research Database (Denmark)

Rosengaard, N. M.; Skriver, Hans Lomholt

1994-01-01

We have performed ab initio calculations of the energies of antiphase boundaries as well as complex and superlattice intrinsic stacking faults in nine intermetallic compounds observed in the face-centered-cubic L1(2) and DO22 structures. The calculations were performed by means of a Green...

Ab initio thermodynamics for the growth of ultra-thin Cu film on a perfect Mg O(001) surface

Energy Technology Data Exchange (ETDEWEB)

Zhukovskii, Yuri F. [Institute for Solid State Physics, University of Latvia, Kengaraga str. 8, Riga LV-1063 (Latvia)]. E-mail: quantzh@latnet.lv; Fuks, David [Materials Engineering Department, Ben-Gurion University of the Negev, POB 653, Beer-Sheva IL-84105 (Israel); Kotomin, Eugene A. [Institute for Solid State Physics, University of Latvia, Kengaraga str. 8, Riga LV-1063 (Latvia); Dorfman, Simon [Department of Physics, Israel Institute of Technology-Technion, Haifa IL-32000 (Israel)

2005-12-15

Controlled growth of thin metallic films on oxide substrates is important for numerous micro-and nano electronic applications. Our ab initio study is devoted to the periodic slab simulations for a series of ordered 2a Cu superlattices on the regular Mg O(001) substrate. Submonolayer and monolayer substrate Cu coverages were calculated using the Daft-Gaga method, as implemented into the Crystal-98 code. The results of ab initio calculations have been combined with thermodynamic theory which allows US to predict the growth mode of ultra-thin metal films (spinodal decomposition vs. nucleation-and-growth regime) as a function of the metal coverage and the temperature, and to estimate the metal density in clusters. We show that 3a cluster formation becomes predominant already at low Cu coverages, in agreement with the experiment.

Ab initio thermodynamics for the growth of ultra-thin Cu film on a perfect Mg O(001) surface

International Nuclear Information System (INIS)

Zhukovskii, Yuri F.; Fuks, David; Kotomin, Eugene A.; Dorfman, Simon

2005-01-01

Controlled growth of thin metallic films on oxide substrates is important for numerous micro-and nano electronic applications. Our ab initio study is devoted to the periodic slab simulations for a series of ordered 2a Cu superlattices on the regular Mg O(001) substrate. Submonolayer and monolayer substrate Cu coverages were calculated using the Daft-Gaga method, as implemented into the Crystal-98 code. The results of ab initio calculations have been combined with thermodynamic theory which allows US to predict the growth mode of ultra-thin metal films (spinodal decomposition vs. nucleation-and-growth regime) as a function of the metal coverage and the temperature, and to estimate the metal density in clusters. We show that 3a cluster formation becomes predominant already at low Cu coverages, in agreement with the experiment

Ab initio molecular dynamics of the reaction of quercetin with superoxide radical

International Nuclear Information System (INIS)

Lespade, Laure

2016-01-01

Highlights: • Ab initio molecular dynamics is performed to describe the reaction of quercetin and superoxide. • The reaction occurs near the sites 4′ and 7 when the system contains sufficiently water molecules. • The difference of reactivity of superoxide compared to commonly used radicals as DPPH · or ABTS ·+ is explained. - Abstract: Superoxide plays an important role in biology but in unregulated concentrations it is implicated in a lot of diseases such as cancer or atherosclerosis. Antioxidants like flavonoids are abundant in plant and are good scavengers of superoxide radical. The modeling of superoxide scavenging by flavonoids from the diet still remains a challenge. In this study, ab initio molecular dynamics of the reaction of the flavonoid quercetin toward superoxide radical has been carried out using Car–Parrinello density functional theory. The study has proven different reactant solvation by modifying the number of water molecules surrounding superoxide. The reaction consists in the gift of a hydrogen atom of one of the hydroxyl groups of quercetin to the radical. When it occurs, it is relatively fast, lower than 100 fs. Calculations show that it depends largely on the environment of the hydroxyl group giving its hydrogen atom, the geometry of the first water layer and the presence of a certain number of water molecules in the second layer, indicating a great influence of the solvent on the reactivity.

Multiscale modeling of current-induced switching in magnetic tunnel junctions using ab initio spin-transfer torques

Science.gov (United States)

Ellis, Matthew O. A.; Stamenova, Maria; Sanvito, Stefano

2017-12-01

There exists a significant challenge in developing efficient magnetic tunnel junctions with low write currents for nonvolatile memory devices. With the aim of analyzing potential materials for efficient current-operated magnetic junctions, we have developed a multi-scale methodology combining ab initio calculations of spin-transfer torque with large-scale time-dependent simulations using atomistic spin dynamics. In this work we introduce our multiscale approach, including a discussion on a number of possible schemes for mapping the ab initio spin torques into the spin dynamics. We demonstrate this methodology on a prototype Co/MgO/Co/Cu tunnel junction showing that the spin torques are primarily acting at the interface between the Co free layer and MgO. Using spin dynamics we then calculate the reversal switching times for the free layer and the critical voltages and currents required for such switching. Our work provides an efficient, accurate, and versatile framework for designing novel current-operated magnetic devices, where all the materials details are taken into account.

The creation, management, and use of data quality information for life cycle assessment.

Science.gov (United States)

Edelen, Ashley; Ingwersen, Wesley W

2018-04-01

Despite growing access to data, questions of "best fit" data and the appropriate use of results in supporting decision making still plague the life cycle assessment (LCA) community. This discussion paper addresses revisions to assessing data quality captured in a new US Environmental Protection Agency guidance document as well as additional recommendations on data quality creation, management, and use in LCA databases and studies. Existing data quality systems and approaches in LCA were reviewed and tested. The evaluations resulted in a revision to a commonly used pedigree matrix, for which flow and process level data quality indicators are described, more clarity for scoring criteria, and further guidance on interpretation are given. Increased training for practitioners on data quality application and its limits are recommended. A multi-faceted approach to data quality assessment utilizing the pedigree method alongside uncertainty analysis in result interpretation is recommended. A method of data quality score aggregation is proposed and recommendations for usage of data quality scores in existing data are made to enable improved use of data quality scores in LCA results interpretation. Roles for data generators, data repositories, and data users are described in LCA data quality management. Guidance is provided on using data with data quality scores from other systems alongside data with scores from the new system. The new pedigree matrix and recommended data quality aggregation procedure can now be implemented in openLCA software. Additional ways in which data quality assessment might be improved and expanded are described. Interoperability efforts in LCA data should focus on descriptors to enable user scoring of data quality rather than translation of existing scores. Developing and using data quality indicators for additional dimensions of LCA data, and automation of data quality scoring through metadata extraction and comparison to goal and scope are needed.

Diet Quality and Cancer Outcomes in Adults: A Systematic Review of Epidemiological Studies

Science.gov (United States)

Potter, Jennifer; Brown, Leanne; Williams, Rebecca L.; Byles, Julie; Collins, Clare E.

2016-01-01

Dietary patterns influence cancer risk. However, systematic reviews have not evaluated relationships between a priori defined diet quality scores and adult cancer risk and mortality. The aims of this systematic review are to (1) describe diet quality scores used in cohort or cross-sectional research examining cancer outcomes; and (2) describe associations between diet quality scores and cancer risk and mortality. The protocol was registered in Prospero, and a systematic search using six electronic databases was conducted through to December 2014. Records were assessed for inclusion by two independent reviewers, and quality was evaluated using a validated tool. Sixty-four studies met inclusion criteria from which 55 different diet quality scores were identified. Of the 35 studies investigating diet quality and cancer risk, 60% (n = 21) found a positive relationship. Results suggest no relationship between diet quality scores and overall cancer risk. Inverse associations were found for diet quality scores and risk of postmenopausal breast, colorectal, head, and neck cancer. No consistent relationships between diet quality scores and cancer mortality were found. Diet quality appears to be related to site-specific adult cancer risk. The relationship with cancer mortality is less conclusive, suggesting additional factors impact overall cancer survival. Development of a cancer-specific diet quality score for application in prospective epidemiology and in public health is warranted. PMID:27399671

Protein structural model selection by combining consensus and single scoring methods.

Directory of Open Access Journals (Sweden)

Zhiquan He

Full Text Available Quality assessment (QA for predicted protein structural models is an important and challenging research problem in protein structure prediction. Consensus Global Distance Test (CGDT methods assess each decoy (predicted structural model based on its structural similarity to all others in a decoy set and has been proved to work well when good decoys are in a majority cluster. Scoring functions evaluate each single decoy based on its structural properties. Both methods have their merits and limitations. In this paper, we present a novel method called PWCom, which consists of two neural networks sequentially to combine CGDT and single model scoring methods such as RW, DDFire and OPUS-Ca. Specifically, for every pair of decoys, the difference of the corresponding feature vectors is input to the first neural network which enables one to predict whether the decoy-pair are significantly different in terms of their GDT scores to the native. If yes, the second neural network is used to decide which one of the two is closer to the native structure. The quality score for each decoy in the pool is based on the number of winning times during the pairwise comparisons. Test results on three benchmark datasets from different model generation methods showed that PWCom significantly improves over consensus GDT and single scoring methods. The QA server (MUFOLD-Server applying this method in CASP 10 QA category was ranked the second place in terms of Pearson and Spearman correlation performance.

Controlling Magnetic and Ferroelectric Order Through Geometry: Synthesis, Ab Initio Theory, Characterization of New Multi-Ferric Fluoride Materials

Energy Technology Data Exchange (ETDEWEB)

Halasyamani, Shiv [Univ. of Houston, TX (United States); Fennie, Craig [Cornell Univ., Ithaca, NY (United States)

2016-11-03

We have focused on the synthesis, characterization, and ab initio theory on multi-functional mixed-metal fluorides. With funding from the DOE, we have successfully synthesized and characterized a variety of mixed metal fluoride materials.

Quality of Web-based information on cocaine addiction.

Science.gov (United States)

Khazaal, Yasser; Chatton, Anne; Cochand, Sophie; Zullino, Daniele

2008-08-01

To evaluate the quality of web-based information on cocaine use and addiction and to investigate potential content quality indicators. Three keywords: cocaine, cocaine addiction and cocaine dependence were entered into two popular World Wide Web search engines. Websites were assessed with a standardized proforma designed to rate sites on the basis of accountability, presentation, interactivity, readability and content quality. "Health on the Net" (HON) quality label, and DISCERN scale scores aiding people without content expertise to assess quality of written health publication were used to verify their efficiency as quality indicators. Of the 120 websites identified, 61 were included. Most were commercial sites. The results of the study indicate low scores on each of the measures including content quality. A global score (the sum of accountability, interactivity, content quality and aesthetic criteria) appeared as a good content quality indicator. While cocaine education websites for patients are widespread, their global quality is poor. There is a need for better evidence-based information about cocaine use and addiction on the web. The poor and variable quality of web-based information and its possible impact on physician-patient relationship argue for a serious provider for patient talk about the health information found on Internet. Internet sites could improve their content using the global score as a quality indicator.

Double ionization in Helium. Ab initio calculations beyond the one dimensional approximation

International Nuclear Information System (INIS)

Camilo Ruiz; Luis Plaja; Luis Roso; Andreas Becker

2006-01-01

Complete test of publication follows. We present ab-initio computations of the ionization of two-electron atoms by short pulses of coherent radiation beyond the one-dimensional approximation. In the model the electron correlation is included in its full dimensionality, while the center-of-mass motion is restricted along the polarization axis. We show some result for Non Sequential Double Ionization (NSDI) as well as for SDI for high intensity low IR frequency. Some recent applications for this correlated system is also presented.

Effects of nutrient profiling and price changes based on NuVal® scores on food purchasing in an online experimental supermarket.

Science.gov (United States)

Epstein, Leonard H; Finkelstein, Eric A; Katz, David L; Jankowiak, Noelle; Pudlewski, Corrin; Paluch, Rocco A

2016-08-01

The goal of the present study was to apply experimental economic methods in an online supermarket to examine the effects of nutrient profiling, and differential pricing based on the nutrient profile, on the overall diet quality, energy and macronutrients of the foods purchased, and diet cost. Participants were provided nutrient profiling scores or price adjustments based on nutrient profile scores while completing a hypothetical grocery shopping task. Prices of foods in the top 20 % of nutrient profiling scores were reduced (subsidized) by 25 % while those in the bottom 20 % of scores were increased (taxed) by 25 %. We evaluated the independent and interactive effects of nutrient profiling or price adjustments on overall diet quality of foods purchased as assessed by the NuVal® score, energy and macronutrients purchased and diet cost in a 2×2 factorial design. A large (>10 000 food items) online experimental supermarket in the USA. Seven hundred and eighty-one women. Providing nutrient profiling scores improved overall diet quality of foods purchased. Price changes were associated with an increase in protein purchased, an increase in energy cost, and reduced carbohydrate and protein costs. Price changes and nutrient profiling combined were associated with no unique benefits beyond price changes or nutrient profiling alone. Providing nutrient profile score increased overall NuVal® score without a reduction in energy purchased. Combining nutrient profiling and price changes did not show an overall benefit to diet quality and may be less useful than nutrient profiling alone to consumers who want to increase overall diet quality of foods purchased.

Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

International Nuclear Information System (INIS)

Han, Huixian; Li, Anyang; Guo, Hua

2014-01-01

A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S 0 ) electronic state has been constructed by fitting ∼37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm −1 . The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies up to 12 700 cm −1 above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction

Ab Initio periodic Hartree-Fock study of group IA cations in ANA-type zeolites

International Nuclear Information System (INIS)

Anchell, J.L.; White, J.C.; Thompson, M.R.; Hess, A.C.

1994-01-01

This study investigates the electronic structure of Group IA cations intercalated into zeolites with the analcime (ANA) framework using ab initio periodic Hartree-Fock theory. The purpose of the study is to gain a better understanding of the role played by electron-donating species in zeolites in general, with specific applications to materials that have been suggested as storage matrices for radioactive materials. The effect of the intercalated species (Na, K, Rb, and Cs) on the electronic structure of the zeolite is presented on the basis of an analysis of the total and projected density of states, Mulliken charges, and charge density differences. The results of those analyses indicate that, relative to a charge neutral atomic state, the Group IA species donate an electron to the zeolite lattice and interact most strongly with the s and p atomic states of oxygen as the species are moved through the lattice. In addition, estimates of the self-diffusion constants of Na, K, Rb, and Cs based upon a one-dimensional diffusion model parameterized from the ab initio total energy data will be presented. 24 refs., 8 figs., 4 tabs

Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

Science.gov (United States)

Han, Huixian; Li, Anyang; Guo, Hua

2014-12-01

A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S0) electronic state has been constructed by fitting ˜37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm-1. The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies up to 12 700 cm-1 above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction.

Quality of web based information on treatment of depression: cross sectional survey.

Science.gov (United States)

Griffiths, K M; Christensen, H

2000-12-16

To evaluate quality of web based information on treatment of depression, to identify potential indicators of content quality, and to establish if accountability criteria are indicators of quality. Cross sectional survey. 21 frequently accessed websites about depression. (i) Site characteristics; (ii) quality of content-concordance with evidence based depression guidelines (guideline score), appropriateness of other relevant site information (issues score), and subjective rating of site quality (global score); and (iii) accountability-conformity with core accountability standards (Silberg score) and quality of evidence cited in support of conclusions (level of evidence score). Although the sites contained useful information, their overall quality was poor: the mean guideline, issues, and global scores were only 4.7 (range 0-13) out of 43, 9.8 (6-14) out of 17, and 3 (0.5-7. 5) out of 10 respectively. Sites typically did not cite scientific evidence in support of their conclusions. The guideline score correlated with the two other quality of content measures, but none of the content measures correlated with the Silberg accountability score. Content quality was superior for sites owned by organisations and sites with an editorial board. There is a need for better evidence based information about depression on the web, and a need to reconsider the role of accountability criteria as indicators of site quality and to develop simple valid indicators of quality. Ownership by an organisation and the involvement of a professional editorial board may be useful indicators. The study methodology may be useful for exploring these issues in other health related subjects.

Cooperative effects in the structuring of fluoride water clusters: Ab initio hybrid quantum mechanical/molecular mechanical model incorporating polarizable fluctuating charge solvent

Science.gov (United States)

Bryce, Richard A.; Vincent, Mark A.; Malcolm, Nathaniel O. J.; Hillier, Ian H.; Burton, Neil A.

1998-08-01

A new hybrid quantum mechanical/molecular mechanical model of solvation is developed and used to describe the structure and dynamics of small fluoride/water clusters, using an ab initio wave function to model the ion and a fluctuating charge potential to model the waters. Appropriate parameters for the water-water and fluoride-water interactions are derived, with the fluoride anion being described by density functional theory and a large Gaussian basis. The role of solvent polarization in determining the structure and energetics of F(H2O)4- clusters is investigated, predicting a slightly greater stability of the interior compared to the surface structure, in agreement with ab initio studies. An extended Lagrangian treatment of the polarizable water, in which the water atomic charges fluctuate dynamically, is used to study the dynamics of F(H2O)4- cluster. A simulation using a fixed solvent charge distribution indicates principally interior, solvated states for the cluster. However, a preponderance of trisolvated configurations is observed using the polarizable model at 300 K, which involves only three direct fluoride-water hydrogen bonds. Ab initio calculations confirm this trisolvated species as a thermally accessible state at room temperature, in addition to the tetrasolvated interior and surface structures. Extension of this polarizable water model to fluoride clusters with five and six waters gave less satisfactory agreement with experimental energies and with ab initio geometries. However, our results do suggest that a quantitative model of solvent polarization is fundamental for an accurate understanding of the properties of anionic water clusters.

Efficacy of the SU(3) scheme for ab initio large-scale calculations beyond the lightest nuclei

Czech Academy of Sciences Publication Activity Database

Dytrych, Tomáš; Maris, P.; Launey, K. D.; Draayer, J. P.; Vary, J. P.; Langr, D.; Saule, E.; Caprio, M. A.; Catalyurek, U.; Sosonkina, M.

2016-01-01

Roč. 207, OCT (2016), s. 202-210 ISSN 0010-4655 R&D Projects: GA ČR GA16-16772S Institutional support: RVO:61389005 Keywords : nuclear structure * Ab initio methods * Shell model * models based on group theory Subject RIV: BE - Theoretical Physics Impact factor: 3.936, year: 2016

Ab-initio crystal structure analysis and refinement approaches of oligo p-benzamides based on electron diffraction data

DEFF Research Database (Denmark)

Gorelik, Tatiana E; van de Streek, Jacco; Kilbinger, Andreas F M

2012-01-01

Ab-initio crystal structure analysis of organic materials from electron diffraction data is presented. The data were collected using the automated electron diffraction tomography (ADT) technique. The structure solution and refinement route is first validated on the basis of the known crystal stru...

Development and validation of a scoring system for late anorectal side-effects in patients treated with radiotherapy for prostate cancer

International Nuclear Information System (INIS)

Petersen, Stine Elleberg; Bentzen, Lise; Emmertsen, Katrine J.; Laurberg, Søren; Lundby, Lilli; Høyer, Morten

2014-01-01

Purpose: To develop and validate a scoring system for evaluation of long term anorectal dysfunction following radiotherapy for prostate cancer. Materials and methods: Patients treated for prostate cancer with radiotherapy filled in questionnaires on anorectal function and quality of life. Items for the condensed anorectal dysfunction score (RT-ARD) were identified and weighted by binomial regression analysis. The score was tested in a separate patient material by receiver operating characteristic (ROC) analysis and correlations to quality of life domains. Results: A total of 309 patients participated in the study. The items selected were “incontinence for solid stool”, “ability to defer defecation”, “unproductive call to stool”, “clustering of stool”, and “mucus in stool.” Patients were grouped into three categories according to the RT-ARD score; 0–8 (no RT-ARD), 9–23 (minor RT-ARD), 24–45 (major RT-ARD). ROC analyses revealed high sensitivity (91%) and specificity (85%) for major RT-ARD. The prediction model demonstrated a perfect fit in 60%, moderate fit in 36% and no fit in 4%. There was good correlation between the RT-ARD score and quality of life. Conclusions: The RT-ARD score is a validated and simple instrument for evaluation of anorectal dysfunction following radiotherapy for prostate cancer, and the RT-ARD score correlates to the patient’s quality of life

Microscopic nucleon spectral function for finite nuclei featuring two- and three-nucleon short-range correlations: The model versus ab initio calculations for three-nucleon systems

Science.gov (United States)

Ciofi degli Atti, Claudio; Mezzetti, Chiara Benedetta; Morita, Hiko

2017-04-01

Background: Two-nucleon (2 N ) short-range correlations (SRC) in nuclei have been recently thoroughly investigated, both theoretically and experimentally and the study of three-nucleon (3 N ) SRC, which could provide important information on short-range hadronic structure, is underway. Novel theoretical ideas concerning 2 N and 3 N SRC are put forward in the present paper. Purpose: The general features of a microscopic one-nucleon spectral function which includes the effects of both 2 N and 3 N SRC and its comparison with ab initio spectral functions of the three-nucleon systems are illustrated. Methods: A microscopic and parameter-free one-nucleon spectral function expressed in terms of a convolution integral involving ab initio relative and center-of-mass (c.m.) momentum distributions of a 2 N pair and aimed at describing two- and three-nucleon short-range correlations, is obtained by using: (i) the two-nucleon momentum distributions obtained within ab initio approaches based upon nucleon-nucleon interactions of the Argonne family; (ii) the exact relation between one- and two-nucleon momentum distributions; (iii) the fundamental property of factorization of the nuclear wave function at short internucleon ranges. Results: The comparison between the ab initio spectral function of 3He and the one based upon the convolution integral shows that when the latter contains only two-nucleon short-range correlations the removal energy location of the peaks and the region around them exhibited by the ab initio spectral function are correctly predicted, unlike the case of the high and low removal energy tails; the inclusion of the effects of three-nucleon correlations brings the convolution model spectral function in much better agreement with the ab initio one; it is also found that whereas the three-nucleon short-range correlations dominate the high energy removal energy tail of the spectral function, their effects on the one-nucleon momentum distribution are almost one

Comparison between s - and d -electron mediated transport in a photoswitching dithienylethene molecule using ab initio transport methods

KAUST Repository

Odell, Anders; Delin, Anna; Johansson, Bö rje; Ulman, Kanchan; Narasimhan, Shobhana; Rungger, Ivan; Sanvito, Stefano

2011-01-01

The influence of the electrode's Fermi surface on the transport properties of a photoswitching molecule is investigated with state-of-the-art ab initio transport methods. We report results for the conducting properties of the two forms

Ab-initio calculation of quasi-particle bandstructure, exciton binding energies and dielectric properties of polythiophene

NARCIS (Netherlands)

van der Horst, J.W.; Bobbert, P.A.; Bobbert, Peter A.; Michels, M.A.J.; Brocks, G.; Kelly, Paul J.

1999-01-01

We use the ab-initio many-body GW method to calculate the quasi-particle spectrum of polythiophene. For the isolated chain, we find a large increase of the gap compared to DFT-LDA calculations (1.2 eV). The result (4.1 eV) exceeds experimental values, due to the absence of long-range screening in

The Rectal Cancer Female Sexuality Score

DEFF Research Database (Denmark)

Thyø, Anne; Emmertsen, Katrine J; Laurberg, Søren

2018-01-01

BACKGROUND: Sexual dysfunction and impaired quality of life is a potential side effect to rectal cancer treatment. OBJECTIVE: The objective of this study was to develop and validate a simple scoring system intended to evaluate sexual function in women treated for rectal cancer. DESIGN......: This is a population-based cross-sectional study. SETTINGS: Female patients diagnosed with rectal cancer between 2001 and 2014 were identified by using the Danish Colorectal Cancer Group's database. Participants filled in the validated Sexual Function Vaginal Changes questionnaire. Women declared to be sexually active...... in the validation group. PATIENTS: Female patients with rectal cancer above the age of 18 who underwent abdominoperineal resection, Hartmann procedure, or total/partial mesorectal excision were selected. MAIN OUTCOME MEASURES: The primary outcome measured was the quality of life that was negatively affected because...

Ab Initio Symmetry-Adapted No-Core Shell Model

International Nuclear Information System (INIS)

Draayer, J P; Dytrych, T; Launey, K D

2011-01-01

A multi-shell extension of the Elliott SU(3) model, the SU(3) symmetry-adapted version of the no-core shell model (SA-NCSM), is described. The significance of this SA-NCSM emerges from the physical relevance of its SU(3)-coupled basis, which – while it naturally manages center-of-mass spuriosity – provides a microscopic description of nuclei in terms of mixed shape configurations. Since typically configurations of maximum spatial deformation dominate, only a small part of the model space suffices to reproduce the low-energy nuclear dynamics and hence, offers an effective symmetry-guided framework for winnowing of model space. This is based on our recent findings of low-spin and high-deformation dominance in realistic NCSM results and, in turn, holds promise to significantly enhance the reach of ab initio shell models.

[Clinical scores for the risk of bleeding with or without anticoagulation].

Science.gov (United States)

Junod, Alain

2016-09-14

The assessment of hemorragic risk related to therapeutic anticoagulation is made difficult because of the variety of existing drugs, the heterogeneity of treatment strategies and their duration. Six prognostic scores have been analyzed. For three of them, external validations have revealed a marked decrease in the discrimination power. One British study, Qbleed, based on the data of more than 1 million of ambulatory patients, has repeatedly satisfied quality criteria. Two scores have also studied the bleeding risk during hospital admission for acute medical disease. The development of new and effective anticoagulants with fewer side-effects is more likely to solve this problem than the production of new clinical scores.

Extension of the lod score: the mod score.

Science.gov (United States)

Clerget-Darpoux, F

2001-01-01

In 1955 Morton proposed the lod score method both for testing linkage between loci and for estimating the recombination fraction between them. If a disease is controlled by a gene at one of these loci, the lod score computation requires the prior specification of an underlying model that assigns the probabilities of genotypes from the observed phenotypes. To address the case of linkage studies for diseases with unknown mode of inheritance, we suggested (Clerget-Darpoux et al., 1986) extending the lod score function to a so-called mod score function. In this function, the variables are both the recombination fraction and the disease model parameters. Maximizing the mod score function over all these parameters amounts to maximizing the probability of marker data conditional on the disease status. Under the absence of linkage, the mod score conforms to a chi-square distribution, with extra degrees of freedom in comparison to the lod score function (MacLean et al., 1993). The mod score is asymptotically maximum for the true disease model (Clerget-Darpoux and Bonaïti-Pellié, 1992; Hodge and Elston, 1994). Consequently, the power to detect linkage through mod score will be highest when the space of models where the maximization is performed includes the true model. On the other hand, one must avoid overparametrization of the model space. For example, when the approach is applied to affected sibpairs, only two constrained disease model parameters should be used (Knapp et al., 1994) for the mod score maximization. It is also important to emphasize the existence of a strong correlation between the disease gene location and the disease model. Consequently, there is poor resolution of the location of the susceptibility locus when the disease model at this locus is unknown. Of course, this is true regardless of the statistics used. The mod score may also be applied in a candidate gene strategy to model the potential effect of this gene in the disease. Since, however, it

Ab initio study of II-(VI){sub 2} dichalcogenides

Energy Technology Data Exchange (ETDEWEB)

Olsson, P; Vidal, J; Lincot, D, E-mail: polsson@kth.se [Institut de R and D sur l' energie photovoltaique (IRDEP), UMR 7174-EDF-CNRS-ENSCP, 6 quai Watier, 78401 Chatou Cedex (France)

2011-10-12

The structural stabilities of the (Zn,Cd)(S,Se,Te){sub 2} dichalcogenides have been determined ab initio. These compounds are shown to be stable in the pyrite phase, in agreement with available experiments. Structural parameters for the ZnTe{sub 2} pyrite semiconductor compound proposed here are presented. The opto-electronic properties of these dichalcogenide compounds have been calculated using quasiparticle GW theory. Bandgaps, band structures and effective masses are proposed as well as absorption coefficients and refraction indices. The compounds are all indirect semiconductors with very flat conduction band dispersion and high absorption coefficients. The work functions and surface properties are predicted. The Te and Se based compounds could be of interest as absorber materials in photovoltaic applications. (paper)

Impact of long term Yoga practice on sleep quality and quality of life in the elderly

Directory of Open Access Journals (Sweden)

Mangesh A Bankar

2013-01-01

Full Text Available Background: Sleep disturbances and decline in the physical functionality are common conditions associated with aging. Pharmacological treatment of sleep disturbances can be associated with various adverse effects. Short term trials of Yoga on sleep have shown beneficial effects. Objectives: To evaluate the effect of long-term Yoga exercises on sleep quality and quality of life (QOL in the elderly. Materials and Methods: This was a cross-sectional study in which data were collected from elderly people aged 60 years or more living in Nagpur city. We employed two types of survey questionnaires: Pittsburgh sleep quality index (PSQI and QOL Leiden-Padua (LEIPAD Questionnaire. A total of 65 elderly men and women who signed an informed consent and completed questionnaires were included in the study. Sleep quality score PSQI and QOL (LEIPAD Questionnaire score of the study group were evaluated and compared with the control group using Mann-Whitney U test. Results: Total PSQI score in Yoga group was lower than that of the control group. Also various QOL scores of the Yoga groups were higher than the control group. Conclusion: Addition of regular Yoga exercises in the daily routine of elderly people can help to achieve good sleep quality as well as improve the QOL.

Ab initio simulations and neutron scattering studies of structure and dynamics in PdH

International Nuclear Information System (INIS)

Totolici, I.E.

2001-07-01

The work presented in this PhD thesis is concerned with the interpretation of the neutron scattering measurements from the palladium hydrogen system by means of ab initio electronic structure calculations. The motivation of performing such calculations was due to recent neutron scattering studies on this system that showed a strong directional dependence to the dynamical structure factor together with a complex dependence on energy. Here we attempt to describe the origin of these features by ab initio simulations of the dynamical structure factor. The method assumes an adiabatic separation of the motion of the proton and palladium atoms. The proton wave functions are calculated by a direct solution of the associated single-particle Schroedinger equation using a plane wave basis set method and a mapping of the adiabatic surface. The Fourier components of the adiabatic potential are obtained from LDA pseudopotential calculations. Using Fermi's golden rule within the Born approximation we were then able to calculate the dynamical structure factor, S(Q,ω), for exciting the proton from its ground state to various excited states as a function of the magnitude and direction of the scattering wave vector. The results are in agreement with the inelastic neutron scattering spectra and allow us to identify the origin of previous inexplicable features, in particular the strong directional dependence to the experimental data. The method was extended to investigate the expansion of the equilibrium lattice constant as a function of the H isotope when the zero-point energy of the proton/deuterium is explicitly taken into account in the relaxation process. The results we obtained predicted a bigger lattice constant for the hydride, as expected. Furthermore, other complex ab initio calculations were carried out in order to describe the origin of the large optic dispersion, seen previously in the coherent neutron scattering data. Our calculated dispersion proved to be in good

Trained-user opinion about Welfare Quality measures and integrated scoring of dairy cattle welfare

DEFF Research Database (Denmark)

de Graaf, S.; Ampe, B.; Winckler, C.

2017-01-01

important by trained users (e.g., measures relating to drinkers) had the highest influence on the WQ overall welfare categorization. Conversely, measures rated as most important by the trained users (e.g., lameness and mortality) had a lower effect on the WQ overall category. In addition, trained users were...... conducted an online survey to examine whether trained users' opinions of the WQ protocol for dairy cattle correspond with the integrated scores (criteria, principles, and overall categorization) calculated according to the WQ protocol. First, the trained users' scores (n = 8–15) for reliability and validity...

Meaningful Change Scores in the Knee Injury and Osteoarthritis Outcome Score in Patients Undergoing Anterior Cruciate Ligament Reconstruction

DEFF Research Database (Denmark)

Ingelsrud, Lina Holm; Terwee, Caroline B; Terluin, Berend

2018-01-01

BACKGROUND: Meaningful change scores in the Knee injury and Osteoarthritis Outcome Score (KOOS) in patients undergoing anterior cruciate ligament (ACL) reconstruction have not yet been established. PURPOSE: To define the minimal important change (MIC) for the KOOS after ACL reconstruction. STUDY...... data for at least one of the KOOS subscales were obtained from 542 (45.3%) participants. Predictive modeling MIC values were 12.1 for the KOOS subscales of Sport and Recreational Function and 18.3 for Knee-Related Quality of Life. These values aid in interpreting within-group improvement over time...... and can be used as responder criteria when comparing groups. The corresponding and much lower values for the subscales of Pain (2.5), Symptoms (-1.2), and Activities of Daily Living (2.4) are the results from patients reporting, on average, only mild problems with these domains preoperatively. Although 4...

The effect of quality circles on job satisfaction and quality of work-life of staff in emergency medical services.

Science.gov (United States)

Hosseinabadi, Reza; Karampourian, Arezou; Beiranvand, Shoorangiz; Pournia, Yadollah

2013-10-01

Quality circles, as a participatory management technique, offer one alternative for dealing with frustration and discontent of today's workers. This study was conducted to investigate the effect of implementation of quality circles on nurses' quality of work-life and job satisfaction. In this study, two emergency medical services (EMS) of Hamedan province were selected and randomly assigned as the experimental and control groups. After the experimental group was trained and quality circles were established in this group, the levels of quality of work-life and job satisfaction were measured in the two groups. Then, the statistical analyses were performed using t-test. After the intervention, the results showed significant differences between the scores of motivational factors (p=0.001), the total scores of job satisfaction (p=0.003), and the scores of some quality of work life (QWL) conceptual categories including the use and development of capacities (p=0.008), the total space of life (p=0.003), and the total scores of QWL (p=0.031) in the experimental group compared to those in the control group. This study confirms the effectiveness of quality circles in improving quality of work-life and job satisfaction of nurses working in EMS, and offers their application as a management method that can be used by EMS managers. Copyright © 2012 Elsevier Ltd. All rights reserved.

Charge carrier motion in disordered conjugated polymers: a multiscale ab-initio study

Energy Technology Data Exchange (ETDEWEB)

Vukmirovic, Nenad; Wang, Lin-Wang

2009-11-10

We developed an ab-initio multiscale method for simulation of carrier transport in large disordered systems, based on direct calculation of electronic states and electron-phonon coupling constants. It enabled us to obtain the never seen before rich microscopic details of carrier motion in conjugated polymers, which led us to question several assumptions of phenomenological models, widely used in such systems. The macroscopic mobility of disordered poly(3- hexylthiophene) (P3HT) polymer, extracted from our simulation, is in agreement with experimental results from the literature.

[New scores in renal transplantation: How can we use them?

Science.gov (United States)

Hazzan, Marc; Frimat, Marie; Glowacki, François; Lionet, Arnaud; Provot, François; Noël, Christian

2017-04-01

In renal transplant medicine, several scores have been recently developed in order to help decision-making in clinical practice. The aim of this update is to focus on these new scores that allow to better estimate the quality of the renal transplant, to refine the allocation policy, to help registration of old recipients on the waiting list, or to evaluate the risk to develop end-stage renal failure after living donation. Copyright © 2017 Association Société de néphrologie. Published by Elsevier Masson SAS. All rights reserved.

Global tilt and lumbar lordosis index: two parameters correlating with health-related quality of life scores-but how do they truly impact disability?

Science.gov (United States)

Boissière, Louis; Takemoto, Mitsuru; Bourghli, Anouar; Vital, Jean-Marc; Pellisé, Ferran; Alanay, Ahmet; Yilgor, Caglar; Acaroglu, Emre; Perez-Grueso, Francisco Javier; Kleinstück, Frank; Obeid, Ibrahim

2017-04-01

Many radiological parameters have been reported to correlate with patient's disability including sagittal vertical axis (SVA), pelvic tilt (PT), and pelvic incidence minus lumbar lordosis (PI-LL). European literature reports other parameters such as lumbar lordosis index (LLI) and the global tilt (GT). If most parameters correlate with health-related quality of life scores (HRQLs), their impact on disability remains unclear. This study aimed to validate these parameters by investigating their correlation with HRQLs. It also aimed to evaluate the relationship between each of these sagittal parameters and HRQLs to fully understand the impact in adult spinal deformity management. A retrospective review of a multicenter, prospective database was carried out. The database inclusion criteria were adults (>18 years old) presenting any of the following radiographic parameters: scoliosis (Cobb ≥20°), SVA ≥5 cm, thoracic kyphosis ≥60° or PT ≥25°. All patients with complete data at baseline were included. Health-related quality of life scores, demographic variables (DVs), and radiographic parameters were collected at baseline. Differences in HRQLs among groups of each DV were assessed with analyses of variance. Correlations between radiographic variables and HRQLs were assessed using the Spearman rank correlation. Multivariate linear regression models were fitted for each of the HRQLs (Oswestry Disability Index [ODI], Scoliosis Research Society-22 subtotal score, or physical component summaries) with sagittal parameters and covariants as independent variables. A p<.05 value was considered statistically significant. Among a total of 755 included patients (mean age, 52.1 years), 431 were non-surgical candidates and 324 were surgical candidates. Global tilt and LLI significantly correlated with HRQLs (r=0.4 and -0.3, respectively) for univariate analysis. Demographic variables such as age, gender, body mass index, past surgery, and surgical or non-surgical candidate

The association between self-reported diet quality and health-related quality of life in rural and urban Australian adolescents.

Science.gov (United States)

Bolton, Kristy A; Jacka, Felice; Allender, Steven; Kremer, Peter; Gibbs, Lisa; Waters, Elizabeth; de Silva, Andrea

2016-10-01

This study examines the relationship between diet quality and health-related quality of life (HRQoL) in rural and urban Australian adolescents, and gender differences. Cross-sectional. Secondary schools. 722 rural and 422 urban students from 19 secondary schools. Self-report dietary-related behaviours, demographic information, HRQoL (AQoL-6D) were collected. Healthy and unhealthy diet quality scores were calculated; multiple linear regression investigated associations between diet quality and HRQoL. Compared to urban students, rural students had higher HRQoL, higher healthy diet score, lower unhealthy diet score, consumed less soft drink and less frequently, less takeaway and a higher proportion consumed breakfast (P health problems. Such interventions should consider gender and locality. © 2016 National Rural Health Alliance Inc.

Benefits of Parallel I/O in Ab Initio Nuclear Physics Calculations

International Nuclear Information System (INIS)

Laghave, Nikhil; Sosonkina, Masha; Maris, Pieter; Vary, James P.

2009-01-01

Many modern scientific applications rely on highly parallel calculations, which scale to 10's of thousands processors. However, most applications do not concentrate on parallelizing input/output operations. In particular, sequential I/O has been identified as a bottleneck for the highly scalable MFDn (Many Fermion Dynamics for nuclear structure) code performing ab initio nuclear structure calculations. In this paper, we develop interfaces and parallel I/O procedures to use a well-known parallel I/O library in MFDn. As a result, we gain efficient input/output of large datasets along with their portability and ease of use in the downstream processing.

Ab initio study of perovskite type oxide materials for solid oxide fuel cells

Science.gov (United States)

Lee, Yueh-Lin

2011-12-01

Perovskite type oxides form a family of materials of significant interest for cathodes and electrolytes of solid oxide fuel cells (SOFCs). These perovskites not only are active catalysts for surface oxygen reduction (OR) reactions but also allow incorporating the spilt oxygen monomers into their bulk, an unusual and poorly understood catalytic mechanism that couples surface and bulk properties. The OR mechanisms can be influenced strongly by defects in perovskite oxides, composition, and surface defect structures. This thesis work initiates a first step in developing a general strategy based on first-principles calculations for detailed control of oxygen vacancy content, transport rates of surface and bulk oxygen species, and surface/interfacial reaction kinetics. Ab initio density functional theory methods are used to model properties relevant for the OR reactions on SOFC cathodes. Three main research thrusts, which focus on bulk defect chemistry, surface defect structures and surface energetics, and surface catalytic properties, are carried to investigate different level of material chemistry for improved understanding of key physics/factors that govern SOFC cathode OR activity. In the study of bulk defect chemistry, an ab initio based defect model is developed for modeling defect chemistry of LaMnO 3 under SOFC conditions. The model suggests an important role for defect interactions, which are typically excluded in previous defect models. In the study of surface defect structures and surface energetics, it is shown that defect energies change dramatically (1˜2 eV lower) from bulk values near surfaces. Based on the existing bulk defect model with the calculated ab initio surface defect energetics, we predict the (001) MnO 2 surface oxygen vacancy concentration of (La0.9Sr0.1 )MnO3 is about 5˜6 order magnitude higher than that of the bulk under typical SOFC conditions. Finally, for surface catalytic properties, we show that area specific resistance, oxygen

Rhinology-specific priority setting for quality improvement: a modified Delphi study from the Quality Improvement Committee of the American Rhinologic Society.

Science.gov (United States)

Rudmik, Luke; Mattos, Jose L; Stokken, Janalee K; Soler, Zachary M; Manes, R Peter; Higgins, Thomas S; Setzen, Michael; Lee, Jivianne; Schneider, John

2017-10-01

Improving the quality of healthcare is a complex and resource intensive process. To optimize the allocation of scarce resources, quality improvement (QI) should focus on high-value diseases that will produce the largest improvement in health system performance. Given the breadth and multidisciplinary nature of sinonasal disease management, the purpose of this study was to transparently develop a prioritized list of sinonasal diseases for QI from the perspective of the specialty of rhinology and the American Rhinologic Society (ARS). The RAND modified Delphi methodology was used to rank the priority of nine sinonasal disease categories from 1 (lowest priority) to 9 (highest priority). Two rounds of ranking along with a teleconference meeting was performed by a panel of 9 experts from the ARS Quality Improvement Committee. The final QI-prioritized list of sinonasal diseases are as follows: chronic rhinosinusitis (CRS) (mean score = 8.9), recurrent acute rhinosinusitis (RARS) (mean score = 7.9), sinonasal neoplasms (mean score = 7.0), anatomic nasal obstruction (mean score = 5.9), refractory epistaxis (mean score = 5.2), complicated acute rhinosinusitis (mean score = 5.2), chronic nonallergic rhinitis (mean score = 4.4), orbital disease (mean score = 4.3), uncomplicated acute rhinosinusitis (mean score = 4.1), and allergy/allergic rhinitis (mean score = 3.7). The three most important disease categories for QI from the perspective of the specialty of rhinology were CRS, RARS, and sinonasal neoplasms. Future studies need to define and validate quality metrics for each of these important disease categories in order to facilitate appropriate measurement and improvement initiatives. © 2017 ARS-AAOA, LLC.

The Influence of Square Planar Platinum Complexes on DNA Bases Pairing. An ab initio DFT Study