Local indicators of geocoding accuracy (LIGA: theory and application
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Jacquez Geoffrey M
2009-10-01
Full Text Available Abstract Background Although sources of positional error in geographic locations (e.g. geocoding error used for describing and modeling spatial patterns are widely acknowledged, research on how such error impacts the statistical results has been limited. In this paper we explore techniques for quantifying the perturbability of spatial weights to different specifications of positional error. Results We find that a family of curves describes the relationship between perturbability and positional error, and use these curves to evaluate sensitivity of alternative spatial weight specifications to positional error both globally (when all locations are considered simultaneously and locally (to identify those locations that would benefit most from increased geocoding accuracy. We evaluate the approach in simulation studies, and demonstrate it using a case-control study of bladder cancer in south-eastern Michigan. Conclusion Three results are significant. First, the shape of the probability distributions of positional error (e.g. circular, elliptical, cross has little impact on the perturbability of spatial weights, which instead depends on the mean positional error. Second, our methodology allows researchers to evaluate the sensitivity of spatial statistics to positional accuracy for specific geographies. This has substantial practical implications since it makes possible routine sensitivity analysis of spatial statistics to positional error arising in geocoded street addresses, global positioning systems, LIDAR and other geographic data. Third, those locations with high perturbability (most sensitive to positional error and high leverage (that contribute the most to the spatial weight being considered will benefit the most from increased positional accuracy. These are rapidly identified using a new visualization tool we call the LIGA scatterplot. Herein lies a paradox for spatial analysis: For a given level of positional error increasing sample density
UV-LIGA: From Development to Commercialization
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Grégoire Genolet
2014-07-01
Full Text Available A major breakthrough in UV-LIGA (Lithographie, Galvanoformung and Abformung started with the use of epoxy-based EPON® SU-8 photoresist in the mid-1990s. Using this photoresist has enabled the fabrication of tall and high aspect ratio structures without the use of a very expensive synchrotron source needed to expose the photoresist layer in X-ray LIGA. SU-8 photoresist appeared to be well-suited for LIGA templates, but also as a permanent material. Based on UV-LIGA and SU-8, Mimotec SA has developed processes to manufacture mold inserts and metallic components for various market fields. From one to three-level parts, from Ni to other materials, from simple to complicated parts with integrated functionalities, UV-LIGA has established itself as a manufacturing technology of importance for prototyping, as well as for mass-fabrication. This paper reviews some of the developments that led to commercial success in this field.
Optical properties of LiGaS2: an ab initio study and spectroscopic ellipsometry measurement
International Nuclear Information System (INIS)
Atuchin, V V; Lin, Z S; Isaenko, L I; Lobanov, S I; Kesler, V G; Kruchinin, V N
2009-01-01
Electronic and optical properties of lithium thiogallate crystal, LiGaS 2 , have been investigated by both experimental and theoretical methods. The plane-wave pseudopotential method based on DFT theory has been used for band structure calculations. The electronic parameters of Ga 3d orbitals have been corrected by the DFT+U methods to be consistent with those measured with x-ray photoemission spectroscopy. Evolution of optical constants of LiGaS 2 over a wide spectral range was determined by developed first-principles theory and dispersion curves were compared with optical parameters defined by spectroscopic ellipsometry in the photon energy range 1.2-5.0 eV. Good agreement has been achieved between theoretical and experimental results.
Metrology study of high precision mm parts made by the deep x-ray lithography (LIGA) technique
International Nuclear Information System (INIS)
Mäder, Olaf; Meyer, Pascal; Saile, Volker; Schulz, Joachim
2009-01-01
Microcomponents are increasingly applied in industrial products, e.g. smallest gears, springs or the watch industry. Apart from their small dimensions, such components are characterized by a high contour accuracy. Industry requires the tolerances to be in the µm range. Measurement of lateral dimensions in the mm range with submicrometer accuracy and precision, however, results in high requirements on measurement technology. The relevance of this problem is illustrated by the fact that the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) has launched the Collaborative Research Center 1159 on 'New Strategies of Measurement and Inspection for the Production of Microsystems and Nanostructures'. The Institut für Mikrostrukturtechnik, Karlsruhe (Institute of Microstructure Technology, Karlsruhe), produces microstructures by means of the LIG(A) technique (German acronym for lithography, electrodeposition, molding). Presently, a coordinate measurement machine equipped with an optical fiber probe to measure these microstructures is being tested. This paper will particularly focus on the precision and accuracy of the machine. The rules of measurement system analysis will be applied for this purpose. Following the elimination of the systematic error, reproducibility of deep-etch x-ray lithography will be highlighted using the LIGA production of gold gears as an example
Solution structure of leptospiral LigA4 Big domain
Energy Technology Data Exchange (ETDEWEB)
Mei, Song; Zhang, Jiahai [Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Xuecheng [School of Life Sciences, Anhui University, Hefei, Anhui 230039 (China); Tu, Xiaoming, E-mail: xmtu@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China)
2015-11-13
Pathogenic Leptospiraspecies express immunoglobulin-like proteins which serve as adhesins to bind to the extracellular matrices of host cells. Leptospiral immunoglobulin-like protein A (LigA), a surface exposed protein containing tandem repeats of bacterial immunoglobulin-like (Big) domains, has been proved to be involved in the interaction of pathogenic Leptospira with mammalian host. In this study, the solution structure of the fourth Big domain of LigA (LigA4 Big domain) from Leptospira interrogans was solved by nuclear magnetic resonance (NMR). The structure of LigA4 Big domain displays a similar bacterial immunoglobulin-like fold compared with other Big domains, implying some common structural aspects of Big domain family. On the other hand, it displays some structural characteristics significantly different from classic Ig-like domain. Furthermore, Stains-all assay and NMR chemical shift perturbation revealed the Ca{sup 2+} binding property of LigA4 Big domain. - Highlights: • Determining the solution structure of a bacterial immunoglobulin-like domain from a surface protein of Leptospira. • The solution structure shows some structural characteristics significantly different from the classic Ig-like domains. • A potential Ca{sup 2+}-binding site was identified by strains-all and NMR chemical shift perturbation.
Solution structure of leptospiral LigA4 Big domain
International Nuclear Information System (INIS)
Mei, Song; Zhang, Jiahai; Zhang, Xuecheng; Tu, Xiaoming
2015-01-01
Pathogenic Leptospiraspecies express immunoglobulin-like proteins which serve as adhesins to bind to the extracellular matrices of host cells. Leptospiral immunoglobulin-like protein A (LigA), a surface exposed protein containing tandem repeats of bacterial immunoglobulin-like (Big) domains, has been proved to be involved in the interaction of pathogenic Leptospira with mammalian host. In this study, the solution structure of the fourth Big domain of LigA (LigA4 Big domain) from Leptospira interrogans was solved by nuclear magnetic resonance (NMR). The structure of LigA4 Big domain displays a similar bacterial immunoglobulin-like fold compared with other Big domains, implying some common structural aspects of Big domain family. On the other hand, it displays some structural characteristics significantly different from classic Ig-like domain. Furthermore, Stains-all assay and NMR chemical shift perturbation revealed the Ca"2"+ binding property of LigA4 Big domain. - Highlights: • Determining the solution structure of a bacterial immunoglobulin-like domain from a surface protein of Leptospira. • The solution structure shows some structural characteristics significantly different from the classic Ig-like domains. • A potential Ca"2"+-binding site was identified by strains-all and NMR chemical shift perturbation.
Temperature rise of the mask-resist assembly during LIGA exposure
International Nuclear Information System (INIS)
Ting, Aili
2004-01-01
Deep X-ray lithography on PMMA resist is used in the LIGA process. The resist is exposed to synchrotron X-rays through a patterned mask and then is developed in a liquid developer to make high aspect ratio microstructures. The limitations in dimensional accuracies of the LIGA generated microstructure originate from many sources, including synchrotron and X-ray physics, thermal and mechanical properties of mask and resist, and from the kinetics of the developer. This work addresses the thermal analysis and temperature rise of the mask-resist assembly during exposure in air at the Advanced Light Source (ALS) synchrotron. The concern is that dimensional errors generated at the mask and the resist due to thermal expansion will lower the accuracy of the lithography. We have developed a three-dimensional finite-element model of the mask and resist assembly that includes a mask with absorber, a resist with substrate, three metal holders, and a water-cooling block. We employed the LIGA exposure-development software LEX-D to calculate volumetric heat sources generated in the assembly by X-ray absorption and the commercial software ABAQUS to calculate heat transfer including thermal conduction inside the assembly, natural and forced convection, and thermal radiation. at assembly outer and/or inner surfaces. The calculations of assembly maximum temperature. have been compared with temperature measurements conducted at ALS. In some of these experiments, additional cooling of the assembly was produced by forced nitrogen flow ('nitrogen jets') directed at the mask surface. The temperature rise in the silicon mask and the mask holder comes directly from the X-ray absorption, but nitrogen jets carry away a significant portion of heat energy from the mask surface, while natural convection carries away negligibly small amounts energy from the holder. The temperature rise in PMMA resist is mainly from heat conducted from the silicon substrate backward to the resist and from the inner
Fabrication of miniaturized electrostatic deflectors using LIGA
International Nuclear Information System (INIS)
Jackson, K.H.; Khan-Malek, C.; Muray, L.P.
1997-01-01
Miniaturized electron beam columns (open-quotes microcolumnsclose quotes) have been demonstrated to be suitable candidates for scanning electron microscopy (SEM), e-beam lithography and other high resolution, low voltage applications. In the present technology, microcolumns consist of open-quotes selectively scaledclose quotes micro-sized lenses and apertures, fabricated from silicon membranes with e-beam lithography, reactive ion beam etching and other semiconductor thin-film techniques. These miniaturized electron-optical elements provide significant advantages over conventional optics in performance and ease of fabrication. Since lens aberrations scale roughly with size, it is possible to fabricate simple microcolumns with extremely high brightness sources and electrostatic objective lenses, with resolution and beam current comparable to conventional e-beam columns. Moreover since microcolumns typically operate at low voltages (1 KeV), the proximity effects encountered in e-beam lithography become negligible. For high throughput applications, batch fabrication methods may be used to build large parallel arrays of microcolumns. To date, the best reported performance with a 1 keV cold field emission cathode, is 30 nm resolution at a working distance of 2mm in a 3.5mm column. Fabrication of the microcolumn deflector and stigmator, however, have remained beyond the capabilities of conventional machining operations and semiconductor processing technology. This work examines the LIGA process as a superior alternative to fabrication of the deflectors, especially in terms of degree of miniaturization, dimensional control, placement accuracy, run-out, facet smoothness and choice of suitable materials. LIGA is a combination of deep X-ray lithography, electroplating, and injection molding processes which allow the fabrication of microstructures
Directory of Open Access Journals (Sweden)
C. Lago Peñas
2010-09-01
Full Text Available
RESUMEN
Los objetivos de este trabajo son dos. En primer lugar estudiar los efectos que tiene disputar un partido de la Liga de Campeones sobre el resultado alcanzado por los equipos en la Liga Española en esa misma semana. En segundo lugar, verificar si la probabilidad de ganar frente a perder en la Liga Española es mayor o no para los equipos con experiencia en la Liga de Campeones frente a aquellos otros conjuntos que disputan por primera vez esta competición. La muestra consiste en 184 partidos de la Liga Española de Fútbol jugados por los equipos que se encontraban simultáneamente disputando la primera fase de la Liga de Campeones en las temporadas 2003-2004, 2004-2005 y 2005-2006. Los datos utilizados en la investigación han sido tomados de la página oficial de la Liga de Campeones, de la Liga Española y suministrados por GECA SPORT.
De acuerdo con los resultados de la estimación de un modelo logit multinomial, disputar un partido de la Liga de Campeones durante la semana de competición no reduce la probabilidad de los equipos de ganar frente a perder en el partido de la Liga Nacional. Incluso tiene un efecto positivo para los equipos debutantes en la competición europea: cuando juegan durante la semana tienen más probabilidades de ganar en la Liga Nacional (p<0,01.
Palabras clave: resultado, fútbol, Liga de Campeones. logit multinomial, Liga Española
ABSTRACT
This paper has two goals. First, studying the impact of playing in the Champions League on the results in the Spanish League. Second, analyzing whether being a beginner team in the
The accuracy of the diffusion theory component of removal-diffusion theory
International Nuclear Information System (INIS)
Donnelly, I.J.
1976-03-01
The neutron fluxes in five neutron shields consisting of water, concrete, graphite, iron and an iron-water lattice respectively, have been calculated using P 1 theory, diffusion theory with the usual transport correction for anisotropic scattering (DT), and diffusion theory with a diagonal transport correction (DDT). The calculations have been repeated using transport theory for the flux above 0.5 MeV and the diffusion theories for lower energies. Comparisons with transport theory calculations reveal the accuracy of each diffusion theory when it is used for flux evaluation at all energies, and also its accuracy when used for flux evaluation below 0.5 MeV given the correct flux above 0.5 MeV. It is concluded that the diffusion component of removal-diffusion theory has adequate accuracy unless the high energy diffusion entering the shield is significantly larger than the removal flux. In general, P 1 and DT are more accurate than DDT and give similar fluxes except for shields having a large hydrogen content, in which case DT is better. Therefore it is recommended that DT be used in preference to P 1 theory or DDT. (author)
A safety-based comparison of pure LigaSure use and LigaSure-tie technique in total thyroidectomy.
Pergel, A; Yucel, A Fikret; Aydin, I; Sahin, D A; Aras, S; Kulacoglu, H
2014-01-01
Sutureless total thyroidectomy by using vessel sealing devices has been shown to be safe in some recent clinical studies. However, some surgeons are still concerned about the use of these energy devices in the vicinity of there current laryngeal nerve and parathyroid glands. The objective of this study was to investigate the effects of the use of pure LigaSure on postoperative complications and to discuss the pertinent literature. A total of 456 patients having undergone a total thyroidectomy operation between June 2009 and March 2011 were included in the study. Data were prospectively collected and retrospectively evaluated. Patients were separated into 2 groups. Group L comprised of 182 patients where onlyLigaSure was used, and group LT consisted of 274 patients where ligation was used in the vicinity of the recurrent laryngeal nerve and parathyroid glands, and LigaSure was used in all other parts of the surgery. Patient's blood calcium values were checked preoperatively and at postoperative 24, 48, and 72 hours. Groups were assessed in terms of demographic properties, thyroid pathology, duration of operation, and postoperative complications. Groups were similar in respect of demographic properties, operation duration, thyroid gland pathology. No mortality rate was recorded. Laboratory hypocalcemia rate was higher in group L (P 0.003), but no significant difference was identified between groups in terms of symptomatic hypocalcemia.No permanent hypocalcemia or recurrent laryngeal nerve injury developed in any of the patients in the two groups. Pure LigaSure for total thyroidectomy may increase laboratory hypocalcemia rate, but not symptomatic hypocalcemia. Hemorrhage related complications were similar and low in the two groups. Ligations in the places close to delicate anatomic structures did not cause longer operative times and may be a safer option in total thyroidectomy. Celsius.
W-band LiGA fabricated klystron
Song, Liqun
2002-01-01
Klystrino-W-band klystron was proposed by scientists at SLAC to satisfy recent applications in advanced accelerators, medical treatment, radars and communications. LiGA (a German acronym for lithographe, galvanoformung, and abformung) is introduced in the fabrication of klystrino for the first time in the history of microwave tube fabrication. The cold test experiments show that LiGA fabrication yields best surface smoothness compared with an alternative way EDM (Electrical Discharge Machining). Resultantly LiGA fabricated klystrino has the smallest wall loss which maximizes the circuit efficiency of the output structure. A multiple-gap coupled cavity is motivated to be employed as the klystrino output cavity for maximizing the efficiency. Klytrino is simulated by 1-D, 2-D and 3-D simulation codes. Particularly a complete klystrino is simulated intensively using 2-D MAGIC Particle-in-Cell (PIC) code either for beam absence or beam presence. Many simulation techniques are developed such as model transformation from 3-D to 2-D, circuit parameter simulation, dispersion characteristic analysis, pre bunched electron beam mode and so on. Klystrino, as a 3-D structure, is modeled by 3-D MAFIA for analyzing the cold circuit properties. 3-D MAGIC is explored to simulate klystrino for the actual structure analysis and actual beam interaction process observation.
Balance Competitivo en las Ligas Europeas de Baloncesto y la NBA
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Jorge García - Unanue
2014-01-01
Full Text Available Las ligas deportivas dependen del equilibrio competitivo entre los equipos para ser atractivas para los espectadores, de ahí la aparición del balance competitivo. Por ello, las distintas ligas deportivas han adquirido diferentes formatos que determinarán su competitividad. El objetivo de este artículo es comparar el balance competitivo de la NBA y las principales ligas europeas, teniendo en cuenta la NBA en su conjunto y cada una de sus conferencias de forma independiente. Las variables utilizadas para medir el balance competitivo han sido el índice Hirschman-Herfindal y las ratios C5 y C8. Los resultados muestran un mejor balance competitivo de la NBA en conjunto respecto a las ligas europeas, sin embargo estas diferencias desaparecen al analizar las conferencias de forma independiente. Se concluye que al tener en cuenta cada una de las conferencias de forma independiente, con una estructura más similar a las ligas europeas, se presenta un balance competitivo parecido bajo los indicadores utilizados. Sin embargo, la NBA incluye limitaciones en la competición que siguen favoreciendo la posibilidad de que sea más atractiva para el espectador.
LiGA Research and Service at CAMD
International Nuclear Information System (INIS)
Goettert, Jost; Datta, Proyag; Desta, Yohannes; Jin, Yoonyoung; Ling Zhonggeng; Singh, Varshni
2006-01-01
Since 1995 CAMD has been offering exposure services, so called print shop for a variety of users interested in making precision High-Aspect-Ratio Microstructures (HARMST) for various application. Services have been expanded beyond only the print shop service in recent years and now include x-ray mask fabrication, substrate preparation for PMMA and SU- 8 resists, electroplating, finishing and molding. Metallic and polymeric parts are now routinely fabricated for precision engineering, micro-fluidic and micro-optic applications. This paper presents a brief overview of the actual status of LiGA services provided at CAMD including ongoing research efforts and examples of LiGA components for different applications
Lavrentyev, A. A.; Gabrelian, B. V.; Vu, Tuan V.; Isaenko, L. I.; Yelisseyev, A. P.; Khyzhun, O. Y.
2018-06-01
Measurements of X-ray photoelectron core-level and valence-band spectra for pristine and irradiated with Ar+ ions surfaces of LiGa0.5In0.5Se2 single crystal, novel nonlinear optical mid-IR selenide grown by a modified vertical Bridgman-Stockbarger technique, are reported. Electronic structure of LiGa0.5In0.5Se2 is elucidated from theoretical and experimental points of view. Notably, total and partial densities of states (DOSs) of the LiGa0.5In0.5Se2 compound are calculated based on density functional theory (DFT) using the augmented plane wave + local orbitals (APW + lo) method. In accordance with the DFT calculations, the principal contributors to the valence band are the Se 4p states, making the main input at the top and in the upper part of the band, while its bottom is dominated by contributions of the valence s states associated with Ga and In atoms. The theoretical total DOS curve peculiarities are found to be in excellent agreement with the shape of the X-ray photoelectron valence-band spectrum of the LiGa0.5In0.5Se2 single crystal. The bottom of the conduction band of LiGa0.5In0.5Se2 is formed mainly by contributions of the unoccupied Ga 4s and In 5s states in almost equal proportion, with somewhat smaller contributions of the unoccupied Se 4p states as well. Our calculations indicate that the LiGa0.5In0.5Se2 compound is a direct gap semiconductor. The principal optical constants of LiGa0.5In0.5Se2 are calculated in the present work.
Estudo de ligas de ouro por XRF e SEM-EDS
Coxito, Afonso Maria Teixeira
2016-01-01
Serve o presente estudo para testar uma metodologia para análise de ligas metálicas, em particular ligas de ouro, utilizando as técnicas de fluorescência de raios-X e microscopia electrónica de varrimento. No contexto do presente estudo, foi identificada a composição das folhas de ouro utilizadas em obras de arte. As técnicas laboratoriais utilizadas foram: Microscopia óptica; Espectroscopia de fluorescência de raios-X com dispersão de energia (EDXRF); Microscopi...
Energy Technology Data Exchange (ETDEWEB)
Kelly, James J. (Sandia National Laboratories, Livermore, CA); Goods, Steven Howard (Sandia National Laboratories, Livermore, CA)
2005-06-01
The report presented below is to appear in ''Electrochemistry at the Nanoscale'', Patrik Schmuki, Ed. Springer-Verlag, (ca. 2005). The history of the LIGA process, used for fabricating dimensional precise structures for microsystem applications, is briefly reviewed, as are the basic elements of the technology. The principal focus however, is on the unique aspects of the electrochemistry of LIGA through-mask metal deposition and the generation of the fine and uniform microstructures necessary to ensure proper functionality of LIGA components. We draw from both previously published work by external researchers in the field as well as from published and unpublished studies from within Sandia.
Investigating Early and Late Complications in Conventional and LigaSure Hemorroidectomy
Directory of Open Access Journals (Sweden)
M Zare
2014-06-01
Full Text Available Introduction: The traditional Milligan-Morgan and the Ferguson operations are still the most used for patients with symptomatic haemorrhoids of III and IV degrees. Nowadays LigaSure is used as a new technique to decrease the complications resulting from conventional hemorroidectomy. In this study, patients were investigated on the basis of the following main outcomes: mean operative time, postoperative pain (score and duration, bleeding loss in operation, early (within the first month after surgery and late (after the first month complications in conventional as well as LigaSure hemorroidectomy. Methods: it is an analytical study conducted on 101 patients aged 19–80 years old of both males and females with III and IV-degree hemorrhoids who had been gone to Shahid Sadoughi hospital between 2011 and 2012. Forty-three patients were treated by conventional diathermy and fifty -eight by LigaSure. Patients received analgesic administration for about 24 hours after operations and, after hospital discharge. In fact, analgesia was administered until 5 days (three times a day. All patients were required to record pain from the first postoperative day until the 28th postoperative day on a self-administered NAS scale (0–10. Results: Patients completed a questionnaire face to face one week, one month, six, and twelve months after the operation. The mean operative time, bleeding loss in operation and return to work were significantly shorter in LS group, whereas there were no difference in hospital stay period, anal stenosis, healing time of wound and retention of urinary. A statistically significant difference in pain score was observed three and four days after the operation. Finally, patients with LigaSure haemorrhoidectomy recovered from pain earlier than those with conventional diathermy. Conclusions: although LigaSure proposes additional costs, it is an effective instrument in order to treat hemorrhoids of III and IV degrees.
Miniature Inchworm Actuators Fabricated by Use of LIGA
Yang, Eui-Hyeok
2003-01-01
Miniature inchworm actuators that would have relatively simple designs have been proposed for applications in which there are requirements for displacements of the order of microns or tens of microns and for the ability to hold their positions when electric power is not applied. The proposed actuators would be members of the class of microelectromechanical systems (MEMS), but would be designed and fabricated following an approach that is somewhat unusual for MEMS. Like other MEMS actuators, the proposed inchworm actuators could utilize thermoplastic, bimetallic, shape-memory-alloy, or piezoelectric actuation principles. The figure depicts a piezoelectric inchworm actuator according to the proposal. As in other inchworm actuators, linear motion of an extensible member would be achieved by lengthening and shortening the extensible member in synchronism with alternately clamping and releasing one and then the other end of the member. In this case, the moving member would be the middle one; the member would be piezoelectric and would be shortened by applying a voltage to it. The two outer members would also be piezoelectric; the release of the clamps on the upper or lower end would be achieved by applying a voltage to the electrodes on the upper or lower ends, respectively, of these members. Usually, MEMS actuators cannot be fabricated directly on the side walls of silicon wafers, yet the geometry of this actuator necessitates such fabrication. The solution, according to the proposal, would be to use the microfabrication technique known by the German acronym LIGA - "lithographie, galvanoformung, abformung," which means lithography, electroforming, molding. LIGA involves x-ray lithography of a polymer film followed by selective removal of material to form a three-dimensional pattern from which a mold is made. Among the advantages of LIGA for this purpose are that it is applicable to a broad range of materials, can be used to implement a variety of designs, including
Directory of Open Access Journals (Sweden)
Manju Soman
2018-04-01
Full Text Available Aim: This study aims at cloning, sequencing, and phylogenetic analysis of a partial CDS of ligA gene in pET-32a - Escherichia coli DH5α system, with the objective of identifying the conserved nature of the ligA gene in the genus Leptospira. Materials and Methods: A partial CDS (nucleotide 1873 to nucleotide 3363 of the ligA gene was amplified from genomic DNA of Leptospira interrogans serovar Canicola by polymerase chain reaction (PCR. The PCR-amplified DNA was cloned into pET-32a vector and transformed into competent E. coli DH5α bacterial cells. The partial ligA gene insert was sequenced and the nucleotide sequences obtained were aligned with the published ligA gene sequences of other Leptospira serovars, using nucleotide BLAST, NCBI. Phylogenetic analysis of the gene sequence was done by maximum likelihood method using Mega 6.06 software. Results: The PCR could amplify the 1491 nucleotide sequence spanning from nucleotide 1873 to nucleotide 3363 of the ligA gene and the partial ligA gene could be successfully cloned in E. coli DH5α cells. The nucleotide sequence when analyzed for homology with the reported gene sequences of other Leptospira serovars was found to have 100% homology to the 1910 bp to 3320 bp sequence of ligA gene of L. interrogans strain Kito serogroup Canicola. The predicted protein consisted of 470 aminoacids. Phylogenetic analysis revealed that the ligA gene was conserved in L. interrogans species. Conclusion: The partial ligA gene could be successfully cloned and sequenced from E. coli DH5α cells. The sequence showed 100% homology to the published ligA gene sequences. The phylogenetic analysis revealed the conserved nature of the ligA gene. Further studies on the expression and immunogenicity of the partial LigA protein need to be carried out to determine its competence as a subunit vaccine candidate.
Accuracy verification methods theory and algorithms
Mali, Olli; Repin, Sergey
2014-01-01
The importance of accuracy verification methods was understood at the very beginning of the development of numerical analysis. Recent decades have seen a rapid growth of results related to adaptive numerical methods and a posteriori estimates. However, in this important area there often exists a noticeable gap between mathematicians creating the theory and researchers developing applied algorithms that could be used in engineering and scientific computations for guaranteed and efficient error control. The goals of the book are to (1) give a transparent explanation of the underlying mathematical theory in a style accessible not only to advanced numerical analysts but also to engineers and students; (2) present detailed step-by-step algorithms that follow from a theory; (3) discuss their advantages and drawbacks, areas of applicability, give recommendations and examples.
General Theory versus ENA Theory: Comparing Their Predictive Accuracy and Scope.
Ellis, Lee; Hoskin, Anthony; Hartley, Richard; Walsh, Anthony; Widmayer, Alan; Ratnasingam, Malini
2015-12-01
General theory attributes criminal behavior primarily to low self-control, whereas evolutionary neuroandrogenic (ENA) theory envisions criminality as being a crude form of status-striving promoted by high brain exposure to androgens. General theory predicts that self-control will be negatively correlated with risk-taking, while ENA theory implies that these two variables should actually be positively correlated. According to ENA theory, traits such as pain tolerance and muscularity will be positively associated with risk-taking and criminality while general theory makes no predictions concerning these relationships. Data from Malaysia and the United States are used to test 10 hypotheses derived from one or both of these theories. As predicted by both theories, risk-taking was positively correlated with criminality in both countries. However, contrary to general theory and consistent with ENA theory, the correlation between self-control and risk-taking was positive in both countries. General theory's prediction of an inverse correlation between low self-control and criminality was largely supported by the U.S. data but only weakly supported by the Malaysian data. ENA theory's predictions of positive correlations between pain tolerance, muscularity, and offending were largely confirmed. For the 10 hypotheses tested, ENA theory surpassed general theory in predictive scope and accuracy. © The Author(s) 2014.
On the accuracy of the asymptotic theory for cylindrical shells
DEFF Research Database (Denmark)
Niordson, Frithiof; Niordson, Christian
1999-01-01
We study the accuracy of the lowest-order bending theory of shells, derived from an asymptotic expansion of the three-dimensional theory of elasticity, by comparing the results of this theory for a cylindrical shell with clamped ends with the results of a solution to the three-dimensional problem....... The results are also compared with those of some commonly used engineering shell theories....
An investigation of fatigue in LIGA Ni MEMS thin films
International Nuclear Information System (INIS)
Allameh, S.M.; Lou, J.; Kavishe, F.; Buchheit, T.; Soboyejo, W.O.
2004-01-01
This paper presents results of an experimental study of fatigue in LIGA Ni micro-electro-mechanical systems (MEMS)/thin films produced by electroplating from a sulfamate bath at a current density of 50 mA/cm 2 . Following a brief description of microstructure and micro-tensile properties, the results of stress-life (S-N) experiments are presented for specimens with thicknesses of 70 and 270 μm. Specimens with the thicker cross-sections (270 μm thick) are shown to have comparable fatigue resistance to annealed bulk Ni in the as-plated condition. The thinner specimens (70 μm thick) have comparable fatigue resistance to hardened Ni, and better fatigue resistance than the thicker samples. The underlying fatigue fracture modes are elucidated via scanning electron microscopy. The implications of the results are then discussed for the failure analysis of LIGA Ni MEMS structures
New technique using LigaSure for endoscopic mucomyotomy of Zenker's diverticulum
DEFF Research Database (Denmark)
Nielsen, Hans Ulrik Kjaerem; Trolle, Waldemar; Rubek, Niclas
2014-01-01
OBJECTIVES/HYPOTHESIS: The purpose of this study is to present a new approach for treatment of Zenker's diverticulum using the LigaSure (Covidien, Mansfield, MA) technique. STUDY DESIGN: A consecutive study with follow-up of 15 patients with Zenker's diverticulum endoscopically treated using...... patients were followed up 5 to 14 months after discharge. RESULTS: The median age of patients was 76 years. The diverticula measured between 2 and 7 cm. The median time of surgery was 33 minutes. All patients but one resumed oral intake within 24 hours. One patient experienced prolonged coughing...... condition. As a new operative instrument, the LigaSure technique constitutes in our opinion a valid and easy alternative for treatment of Zenker's diverticulum compared to other endoscopic techniques....
On the accuracy of the asymptotic theory for cylindrical shells
DEFF Research Database (Denmark)
Niordson, Frithiof; Niordson, Christian
1999-01-01
We study the accuracy of the lowest-order bending theory of shells, derived from an asymptotic expansion of the three-dimensional theory of elasticity, by comparing the results of this shell theory for a cylindrical shell with clamped ends with the results of a solution to the three......-dimensional problem. The results are also compared with those of some commonly used engineering shell theories....
Core level photoelectron spectroscopy of LiGaS2 and Ga-S bonding in complex sulfides
International Nuclear Information System (INIS)
Atuchin, V.V.; Isaenko, L.I.; Kesler, V.G.; Lobanov, S.I.
2010-01-01
The electronic parameters of the lithium thiogallate LiGaS 2 have been evaluated by X-ray photoelectron spectroscopy (XPS). Spectral features of all constituent element core levels and Auger lines have been considered. The Ga-S bonding effects in Ga-bearing sulfide crystals have been discussed using binding energy difference Δ 2p (S-Ga) = BE(S 2p) - BE(Ga 3d) as a representative parameter to quantify the valence electron shift from gallium to sulfur atoms. The value Δ 2p (S-Ga) = 141.9 eV found for LiGaS 2 is very close to that evaluated for AgGaS 2 . This relation is an indicator of closely coincident ionicity of Ga-S bonds in LiGaS 2 and AgGaS 2 .
Zhu, Hui; Shuman, Stewart
2005-04-01
NAD+-dependent DNA ligase (LigA) is essential for bacterial growth and a potential target for antimicrobial drug discovery. Here we queried the role of 14 conserved amino acids of Escherichia coli LigA by alanine scanning and thereby identified five new residues within the nucleotidyltransferase domain as being essential for LigA function in vitro and in vivo. Structure activity relationships were determined by conservative mutagenesis for the Glu-173, Arg-200, Arg-208, and Arg-277 side chains, as well as four other essential side chains that had been identified previously (Lys-115, Asp-117, Asp-285, and Lys-314). In addition, we identified Lys-290 as important for LigA activity. Reference to the structure of Enterococcus faecalis LigA allowed us to discriminate three classes of essential/important side chains that: (i) contact NAD+ directly (Lys-115, Glu-173, Lys-290, and Lys-314); (ii) comprise the interface between the NMN-binding domain (domain Ia) and the nucleotidyltransferase domain or comprise part of a nick-binding site on the surface of the nucleotidyltransferase domain (Arg-200 and Arg-208); or (iii) stabilize the active site fold of the nucleotidyltransferase domain (Arg-277). Analysis of mutational effects on the isolated ligase adenylylation and phosphodiester formation reactions revealed different functions for essential side chains at different steps of the DNA ligase pathway, consistent with the proposal that the active site is serially remodeled as the reaction proceeds.
Wang, Li Kai; Zhu, Hui; Shuman, Stewart
2009-03-27
NAD(+)-dependent DNA ligases (LigA) are ubiquitous in bacteria, where they are essential for growth and present attractive targets for antimicrobial drug discovery. LigA has a distinctive modular structure in which a nucleotidyltransferase catalytic domain is flanked by an upstream NMN-binding module and by downstream OB-fold, zinc finger, helix-hairpin-helix, and BRCT domains. Here we conducted a structure-function analysis of the nucleotidyltransferase domain of Escherichia coli LigA, guided by the crystal structure of the LigA-DNA-adenylate intermediate. We tested the effects of 29 alanine and conservative mutations at 15 amino acids on ligase activity in vitro and in vivo. We thereby identified essential functional groups that coordinate the reactive phosphates (Arg(136)), contact the AMP adenine (Lys(290)), engage the phosphodiester backbone flanking the nick (Arg(218), Arg(308), Arg(97) plus Arg(101)), or stabilize the active domain fold (Arg(171)). Finer analysis of the mutational effects revealed step-specific functions for Arg(136), which is essential for the reaction of LigA with NAD(+) to form the covalent ligase-AMP intermediate (step 1) and for the transfer of AMP to the nick 5'-PO(4) to form the DNA-adenylate intermediate (step 2) but is dispensable for phosphodiester formation at a preadenylylated nick (step 3).
Long-term results using LigaSure™ 5 mm instrument for treatment of Zenker's diverticulum
DEFF Research Database (Denmark)
Andersen, Michelle Fog; Trolle, Waldemar; Anthonsen, Kristian
2017-01-01
The purpose of the present study was to evaluate the long-term results and patient's satisfaction of a new approach using the LigaSure™ 5 mm instrument for treatment of Zenker's diverticulum (ZD) and to compare with other long-term results using traditional treatment modalities. Between December ...... to traditional endoscopic techniques and is now the standard treatment method for ZD in our departments.......The purpose of the present study was to evaluate the long-term results and patient's satisfaction of a new approach using the LigaSure™ 5 mm instrument for treatment of Zenker's diverticulum (ZD) and to compare with other long-term results using traditional treatment modalities. Between December......%) reported no symptoms at all. Our results suggest that endoscopic management of ZD with the LigaSure™ 5 mm instrument is a minimally invasive, fast and safe method with solid long-term outcome with relief of symptoms and patient satisfaction. This new operative instrument was not found inferior...
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Cibele Andrucioli de Mattos Pimenta
1998-10-01
Full Text Available Os objetivos deste estudo foram descrever um programa extracurricular de educação em dor, organizado na forma de Liga, e identificar a opinião dos alunos sobre esse modelo de ensino. O Estatuto e o Regimento Interno da Liga de Dor foram as fontes e dados para a descrição da sua organização e funcionamento. Todos os alunos que frequentaram a Liga de Dor nos anos de 1995 e 1996 foram solicitados a responder um questionário sobre suas experiências na Liga. A Liga de Dor foi organizada sob o patrocínio do Centro Acadêmico Osvaldo Cruz, da Faculdade de Medicina da USP, e Centro Acadêmico XXXI de Outubro, da Escola de Enfermagem da USP, em 1995. É composta por alunos dessas duas faculdades e profissionais enfermeiros e médicos, de várias especialidades. Todas as atividades são voluntárias, desenvolvidas em período extracurricular e os estudantes dirigem a Liga. Os objetivos da Liga são: melhorar a qualidade do ensino sobre dor nas escolas médica e de enfermagem, desenvolver pesquisas relativas à epidemiologia, clínica e controle da dor e promover modelo de assistência multidisciplinar e multiprofissional. A maioria dos alunos expressou ter alcançado seus objetivos, total ou parcialmente; ter aumentado seu conhecimento sobre as síndromes álgicas e sobre o manejo do doente com dor; sentir-se gratificado com sua atividade; que o tema dor deveria ser incluído no currículo de modo mais específico e que recomendaria a outros colegas a participação na Liga de Dor. As opiniões dos estudantes mostraram que a Liga de Dor pode ser um modelo útil para a introdução do ensino da dor nos cursos de graduação e enfermagem e de medicina.Although anatomical and physiological base of pain are subject of the basic sciences in health undergraduate curriculum, it is not usually to have pain, concepts and therapy into undergraduate programs. Describing the League Against Pain objectives and organization and the students' opinions about
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Eduardo André Alberti
2015-06-01
Full Text Available ResumoA manufatura aditiva é um processo utilizado para a construção e reparos de peças que possuem geometria complexa ou que necessitem de gradiente de propriedades. Nessa técnica múltiplas camadas são depositadas para a construção da geometria do componente. O sucesso desse procedimento depende de fatores como a técnica de deposição, parâmetros, liga a ser depositada e condições da deposição, como temperatura e atmosfera protetora. Neste estudo, o potencial da técnica de Plasma por arco transferido para manufatura aditiva foi avaliado produzindo “paredes finas”, construídas a partir da sobreposição de cordões. Foram utilizadas duas ligas a base de níquel, uma endurecida por precipitação e outra endurecida por solução sólida. Durante os trabalhos, foram selecionados os parâmetros de processamentos, incluindo a avaliação do efeito do pré-aquecimento a 300°C. Resultados mostraram que a composição química da liga influencia a geometria da parede construída assim como a utilização de pré-aquecimento. Estruturas de solidificação exibindo dendritas refinadas com crescimento epitaxial entre camadas são identificadas. Entretanto, as características da liga determinam o perfil de dureza ao longo da seção transversal, sendo a liga endurecida por precipitação influenciada pelos ciclos térmicos de deposição e a liga endurecida por solução sólida pela diluição com o substrato. Em qualquer dos casos é recomendado a aplicação de tratamento térmico pós-soldagem para uniformização das propriedades.
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Analía Percíncula
2012-01-01
Full Text Available La última dictadura militar arrasó con los procesos organizativos de todo el país, a la vez que introdujo las bases del modelo de acumulación neoliberal. En el nordeste argentino esto implicó, entre otras cosas, la represión y desarticulación de las Ligas Agrarias Chaqueñas y de las Ligas Agrarias Correntinas, organizaciones que en ambos casos representaron las reivindicaciones de los sectores rurales subalternos. Paralelamente, se produjo el desmantelamiento de las producciones de algodón en el Chaco y de tabaco criollo en Corrientes, las cuales estaban en manos de productores directos, quienes se habían organizado en sus respectivas Ligas Agrarias.En este trabajo proponemos un acercamiento, en clave comparativa, a las transformaciones de la estructura agropecuaria que caracterizó a ambas provincias hasta la década del 70 y los actores colectivos conformados a partir de dicha red de relaciones socioeconómicas y políticas, es decir, las Ligas Agrarias Chaqueñas y Correntinas.
Miniature Scroll Pumps Fabricated by LIGA
Wiberg, Dean; Shcheglov, Kirill; White, Victor; Bae, Sam
2009-01-01
Miniature scroll pumps have been proposed as roughing pumps (low - vacuum pumps) for miniature scientific instruments (e.g., portable mass spectrometers and gas analyzers) that depend on vacuum. The larger scroll pumps used as roughing pumps in some older vacuum systems are fabricated by conventional machining. Typically, such an older scroll pump includes (1) an electric motor with an eccentric shaft to generate orbital motion of a scroll and (2) conventional bearings to restrict the orbital motion to a circle. The proposed miniature scroll pumps would differ from the prior, larger ones in both design and fabrication. A miniature scroll pump would include two scrolls: one mounted on a stationary baseplate and one on a flexure stage (see figure). An electromagnetic actuator in the form of two pairs of voice coils in a push-pull configuration would make the flexure stage move in the desired circular orbit. The capacitance between the scrolls would be monitored to provide position (gap) feedback to a control system that would adjust the drive signals applied to the voice coils to maintain the circular orbit as needed for precise sealing of the scrolls. To minimize power consumption and maximize precision of control, the flexure stage would be driven at the frequency of its mechanical resonance. The miniaturization of these pumps would entail both operational and manufacturing tolerances of pump components. In addition, the vibrations of conventional motors and ball bearings exceed these tight tolerances by an order of magnitude. Therefore, the proposed pumps would be fabricated by the microfabrication method known by the German acronym LIGA ( lithographie, galvanoformung, abformung, which means lithography, electroforming, molding) because LIGA has been shown to be capable of providing the required tolerances at large aspect ratios.
A LigA three-domain region protects hamsters from lethal infection by Leptospira interrogans.
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Mariana L Coutinho
2011-12-01
Full Text Available The leptospiral LigA protein consists of 13 bacterial immunoglobulin-like (Big domains and is the only purified recombinant subunit vaccine that has been demonstrated to protect against lethal challenge by a clinical isolate of Leptospira interrogans in the hamster model of leptospirosis. We determined the minimum number and location of LigA domains required for immunoprotection. Immunization with domains 11 and 12 was found to be required but insufficient for protection. Inclusion of a third domain, either 10 or 13, was required for 100% survival after intraperitoneal challenge with Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130. As in previous studies, survivors had renal colonization; here, we quantitated the leptospiral burden by qPCR to be 1.2×10(3 to 8×10(5 copies of leptospiral DNA per microgram of kidney DNA. Although renal histopathology in survivors revealed tubulointerstitial changes indicating an inflammatory response to the infection, blood chemistry analysis indicated that renal function was normal. These studies define the Big domains of LigA that account for its vaccine efficacy and highlight the need for additional strategies to achieve sterilizing immunity to protect the mammalian host from leptospiral infection and its consequences.
El uso de las redes sociales y el engagement de los clubes de la Liga Endesa ACB
Herrera-Torres, L.; Pérez-Tur, F.; García-Fernández, J.; Fernández-Gavira, J.
2017-01-01
Las redes sociales se han convertido en una plataforma idónea para dar a conocer y aumentar la visibilidad de una marca o empresa y también, para interactuar y analizar las acciones de los fans y seguidores de estas. Debido a ello, el presente estudio pretende averiguar las diferentes redes sociales que emplean los clubes de baloncesto de la Liga Endesa ACB, examinar el Engagement de Facebook y Twitter y, analizar si existe una correlación entre la posición en el ranking al final de la liga, ...
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Chun-Chieh Yeh
2015-01-01
Full Text Available Safety of either LigaSure or rubber band in closing inflamed appendiceal stump in acute appendicitis has been less investigated. In this study, cecal ligation followed by resecting inflamed cecum was performed to mimic appendectomy in a rat model of acute appendicitis. Rats were sacrificed immediately (Group A and 7 days (Group B after cecal resection, respectively. The cecal stumps were closed by silk ligature (S, 5 mm LigaSure (L, or rubber band (R. Seven days after cecal resection, the LigaSure (BL and silk subgroups (BS had significantly less intra-abdominal adhesion and better laparotomy wound healing than rubber band subgroup (BR. The initial bursting pressure at cecal stump was comparable among the three methods; along with tissue healing process, both BL and BS provided a higher bursting pressure than BR 7 days after appendectomy. BL subgroup had more abundant hydroxyproline deposition than BS and BR subgroup. Furthermore, serum TNF-α in BR group kept persistently increasing along with time after cecal resection. Thus, the finding that LigaSure but not rubber band is safe in sealing off the inflamed cecal stump in rat model of acute appendicitis suggests the possibility of applying LigaSure for appendectomy via single port procedure or natural orifice transluminal endoscopic surgery (NOTES.
LigaSure small jaws versus cold knife dissection in superficial parotidectomy
DEFF Research Database (Denmark)
Hahn, Christoffer Holst; Sørensen, Christian Hjort
2013-01-01
parotidectomy, and 19 patients had cold knife parotidectomy. Operative time, blood loss, facial palsy and other complications were assessed. The use of LigaSure was associated with a significant reduction in mean operative time (128 min vs. 155, p = 0.04) and intraoperative blood loss (40 mL vs. 115 mL, p ...
40 keV Shaped electron beam lithography for LIGA intermediate mask fabrication
Luttge, R.; Adam, D.; Burkhardt, F.; Hoke, F.; Schacke, H.; Schmidt, M.; Wolf, H.; Schmidt, A.
1999-01-01
High precision LIGA masks require a soft X-ray pattern transfer from intermediate masks by means of electron beam lithography. Such a process has been realized using an upgraded Leica ZBA 23 machine with an acceleration voltage of 40 kV. Three process variations of the developer system, so called GG
Oliveira, Danniel Ferreira de
2009-01-01
Ligas Cu-Al-Ni e Cu-Al-Be forma elaboradas sob atmosfera ambiente e caracterizadas por microscopia, difração de R-X e Calorimetria Diferencial de varredura. Foram realizados nestas ligas ensaios de tração, recuperação de forma e superelasticidade. As propriedades termomecânicas destas ligas realizadas em diferentes temperaturas permitiu concluir que as ligas Cu-Al-Ni podem ser utilizadas como atuadores mecânicos para temperaturas acima de 90°C e que estas ligas não devem ser empregadas em tem...
Liga NiCrSiBC: Microestrutura e Dureza de Revestimentos Processados a Arco e a Laser
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Leandro J. da Silva
2015-03-01
Full Text Available A técnica de processamento é determinante sobre características de um revestimento. Isso porque o aporte térmico, que depende da técnica e dos parâmetros, tem influência sobre a diluição e a taxa de solidificação. Em ligas com baixa complexidade metalúrgica, o impacto do processamento com técnicas de deposição que impõem maior taxa de resfriamento podem se traduzir em refino da microestrutura. Espera-se que quanto mais refinada a microestrutura maior a resistência mecânica do revestimento. Entretanto, na deposição de ligas de maior complexidade metalúrgica isso nem sempre ocorre, porque a elevada taxa de resfriamento pode suprimir formação/precipitação de fases responsáveis pela resistência. Neste estudo, a influência do processamento sobre microestrutura e dureza de revestimentos da liga Colmonoy-6® foi avaliada. A liga foi processada por plasma com arco transferido (PTA e laser de diodo de alta potência (HPDL sobre chapas de AISI 304 com dois níveis de diluição. Em ambos os casos, revestimentos de boa qualidade e livres defeitos foram obtidos. O aumento do teor de Fe (diluição e as diferentes taxas de resfriamento decorrem do processamento com diferentes parâmetros e técnicas. Em consequência, ocorrem mudanças significativas na microestrutura e na dureza dos revestimentos que estão associadas à distribuição, morfologia e composição química dos carbonetos e, principalmente, dos boretos.
Matsunaga, James; Medeiros, Marco A; Sanchez, Yolanda; Werneid, Kristian F; Ko, Albert I
2007-10-01
The life cycle of the pathogen Leptospira interrogans involves stages outside and inside the host. Entry of L. interrogans from moist environments into the host is likely to be accompanied by the induction of genes encoding virulence determinants and the concomitant repression of genes encoding products required for survival outside of the host. The expression of the adhesin LigA, the haemolysin Sph2 (Lk73.5) and the outer-membrane lipoprotein LipL36 of pathogenic Leptospira species have been reported to be regulated by mammalian host signals. A previous study demonstrated that raising the osmolarity of the leptospiral growth medium to physiological levels encountered in the host by addition of various salts enhanced the levels of cell-associated LigA and LigB and extracellular LigA. In this study, we systematically examined the effects of osmotic upshift with ionic and non-ionic solutes on expression of the known mammalian host-regulated leptospiral genes. The levels of cell-associated LigA, LigB and Sph2 increased at physiological osmolarity, whereas LipL36 levels decreased, corresponding to changes in specific transcript levels. These changes in expression occurred irrespective of whether sodium chloride or sucrose was used as the solute. The increase of cellular LigA, LigB and Sph2 protein levels occurred within hours of adding sodium chloride. Extracellular Sph2 levels increased when either sodium chloride or sucrose was added to achieve physiological osmolarity. In contrast, enhanced levels of extracellular LigA were observed only with an increase in ionic strength. These results indicate that the mechanisms for release of LigA and Sph2 differ during host infection. Thus, osmolarity not only affects leptospiral gene expression by affecting transcript levels of putative virulence determinants but also affects the release of such proteins into the surroundings.
Avaliação de Revestimentos de Liga de Níquel 625 Depositados pelo Processo Eletroescória
Sandes, Soraia Simões; Alvarães, Camila Pereira; Mendes, Matheus Campolina; Araújo, Leonardo Sales; Souza, Luis Felipe Guimarães de; Jorge, Jorge Carlos Ferreira
2017-01-01
Resumo A aplicação de revestimentos de ligas de níquel é comumente realizada na indústria de petróleo e gás para aumento da vida de equipamentos em ambientes agressivos, dado que este procedimento melhora a resistência à corrosão, sem um aumento significativo do custo de produção quando comparado com equipamentos maciços fabricados com outras ligas. Normalmente, as juntas são soldadas pelos processos de eletrodos revestidos, MIG/MAG ou TIG. Neste aspecto, o processo eletroescória realiza depo...
Abreu, F.; Sabariz, A.; Quadro, A.; Bueno, A.
2012-01-01
Atualmente, as ligas de alumínio da série 6xxx vêm ocupando um espaço importante na produção global das ligas de alumínio. A utilização em larga escala dessa classe de ligas é consequência da melhoria de suas propriedades mecânicas quando submetidas a tratamentos térmicos. No entanto, a realização de tratamentos térmicos de solubilização e a precipitação de fases metaestáveis durante o envelhecimento podem prejudicar consideravelmente a resistência à corrosão dessa classe de ligas. O presente...
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Lílian Lima Gonçalves dos Prazeres
2017-12-01
Full Text Available This paper, about the reading strategies connections and inferences in the scope of teaching, aims to reflect on the teaching of literary reading, as active literacy, and propose the use of these strategies. We used theories of Solé (1996, Soares (1998, Cosson (2012, Girotto and Souza (2010 in a bibliographical and purposive approaches. The research resulted in the production of a didactic proposal directed to Basic Education, contextualized from the work Liga-Desliga, but that can take as starting point other literary works.
A Transdermal Drug Delivery System Based on LIGA Technology and Soft Lithography
Matteucci, Marco; Perennes, Frederic; Marmiroli, Benedetta; Di Fabrizio, Enzo
2007-01-01
This report presents a transdermal drug delivery system based on LIGA fabricated microparts. It is a portable device combining a magnetically actuated micro gear pump with a microneedle array. The fluidic behaviour of the system is analyzed in order to predict its performance according to the dimension of the microparts and then compared to experimental data. The manufacturing process of both micropump and microneedle array are described.
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ROLLO João Manuel Domingos de Almeida
1999-01-01
Full Text Available Uma das aplicações tecnológicas em que é necessário haver compatibilidade entre um material cerâmico e um material metálico é a confecção de restaurações odontológicas do tipo metalocerâmica. Neste caso, uma porcelana é fundida sobre um substrato metálico para obtenção da prótese de um dente. O requisito fundamental para o sucesso da união metalocerâmica é a adequação dos coeficientes de expansão térmica de cada um dos materiais, de forma a se obter um estado de tensão de compressão adequado na camada cerâmica. Este trabalho propôs-se a levantar as curvas de expansão térmica de ligas Ni-Cr e porcelanas odontológicas, através da técnica de dilatometria e verificar a possível compatibilidade térmica dos pares metal/cerâmica. Simulando a entrada de um novo produto no mercado, desenvolveu-se uma liga Ni-Cr experimental denominada SR, que foi comparada a uma liga comercial de Ni-Cr bastante utilizada em restaurações metalocerâmicas. A partir da análise das curvas de expansão térmica, foi possível verificar a compatibilidade dos pares metal/cerâmica quanto à dilatação térmica, segundo os conceitos preconizados por YAMAMOTO7 (1985. Sob este aspecto, a liga experimental apresentou valores que a incluem como mais uma opção na família de ligas Ni-Cr para utilização em restaurações metalocerâmicas. Os resultados obtidos indicam que o equipamento e a metodologia utilizados são adequados para análise comparativa da compatibilidade térmica entre ligas metálicas Ni-Cr e porcelanas odontológicas.
Castiblanco-Valencia, Mónica M; Fraga, Tatiana R; Breda, Leandro C D; Vasconcellos, Sílvio A; Figueira, Cláudio P; Picardeau, Mathieu; Wunder, Elsio; Ko, Albert I; Barbosa, Angela S; Isaac, Lourdes
2016-05-01
Leptospiral immunoglobulin-like (Lig) proteins are surface exposed molecules present in pathogenic but not in saprophytic Leptospira species. We have previously shown that Lig proteins interact with the soluble complement regulators Factor H (FH), FH like-1 (FHL-1), FH related-1 (FHR-1) and C4b Binding Protein (C4BP). In this study, we used the saprophyte L. biflexa serovar Patoc as a surrogate host to address the specific role of LigA and LigB proteins in leptospiral complement evasion. L. biflexa expressing LigA or LigB was able to acquire FH and C4BP. Bound complement regulators retained their cofactor activities of FI in the proteolytic cleavage of C3b and C4b. Moreover, heterologous expression of ligA and ligB genes in the saprophyte L. biflexa enhanced bacterial survival in human serum. Complement deposition on lig-transformed L. biflexa was assessed by flow cytometry analysis. With regard to MAC deposition, L. biflexa expressing LigA or LigB presented an intermediate profile: MAC deposition levels were greater than those found in the pathogenic L. interrogans, but lower than those observed for L. biflexa wildtype. In conclusion, Lig proteins contribute to in vitro control of complement activation on the leptospiral surface, promoting an increased bacterial survival in human serum. Copyright © 2016 European Federation of Immunological Societies. All rights reserved.
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CENTOLA André Luiz Baracchini
2000-01-01
Full Text Available Os autores estudaram o efeito de quatro diferentes técnicas de polimento de restaurações de amálgama feitas em laboratório com duas ligas convencionais e três ligas com alto teor de cobre, sendo o polimento realizado no tempo de 168 horas após a condensação. A utilização de brocas multilaminadas para o acabamento superficial dos corpos-de-prova exibiu níveis de rugosidade semelhante aos corpos-de-prova não polidos. No tocante às ligas utilizadas, a liga DFL mostrou os mais altos valores de rugosidade superficial, enquanto a liga GS 80 exibiu os melhores valores. A trituração foi efetuada segundo a indicação dos fabricantes e o amálgama foi condensado em uma matriz de aço fabricada especialmente para a pesquisa. A matriz tinha uma cavidade de 4,0 mm de diâmetro com 2,0 mm de profundidade. Cinco minutos após a condensação, foi feita a escultura com uma lâmina de aço e em seguida a brunidura. Depois de 25 minutos, o corpo-de-prova de amálgama era retirado utilizando-se um parafuso da própria matriz. Então, 168 h após a condensação, os corpos-de-prova eram polidos e submetidos aos testes de rugosimetria.
UV-LIGA technique for ECF micropumps using back UV exposure and self-alignment
Han, D.; Xia, Y.; Yokota, S.; Kim, J. W.
2017-12-01
This paper proposes and develops a novel UV-LIGA technique using back UV exposure and self-alignment to realize high aspect ratio micromachining (HARM) in high power density electro-conjugate fluid (ECF) micropumps. ECF is a functional fluid designed to be able to generate strong and active jet flow (ECF jetting) between anode and cathode in ECF when high DC voltage is applied. We have developed high power density ECF micropumps consisting of triangular prism and slit electrode pairs (TPSEs) fabricated by HARM. The traditional UV-LIGA technique for HARM is mainly divided into two approaches: (a) single thick layer and (b) multiple thin layers. Both methods have limitations—deformed molds in the former and misalignment between layers in the latter. Using the finite element method software COMSOL Multiphysics, we demonstrate that the deformed micro-molds critically impair the performance of ECF micropumps. In addition, we experimentally prove that the misalignment would easily trigger electric discharge in the ECF micropumps. To overcome these limitations, we conceive a new concept utilizing the seed electrode layer for electroforming as the UV shield and pattern photoresist (KMPR) by back UV exposure. The seed electrode layer should be composed of a non-transparent conductor (Au/Ti) for patterning and a transparent conductor (ITO) for wiring. Instead of ITO, we propose the concept of transparency-like electrodes comprised of thin metal line patterns. To verify this concept, KMPR layers with thicknesses of 70, 220, and 500 µm are experimentally investigated. In the case of 500 µm KMPR thickness, the concept of transparency-like electrode was partially proved. As a result, TPSEs with a height of 440 µm were successfully fabricated. Characteristic experiments demonstrated that ECF micropumps (367 mW cm-3) fabricated by back UV achieved almost the same output power density as ECF micropumps (391 mW cm-3) fabricated by front UV. This paper proves that the proposed
UV-LIGA technique for ECF micropumps using back UV exposure and self-alignment
International Nuclear Information System (INIS)
Han, D; Xia, Y; Yokota, S; Kim, J W
2017-01-01
This paper proposes and develops a novel UV-LIGA technique using back UV exposure and self-alignment to realize high aspect ratio micromachining (HARM) in high power density electro-conjugate fluid (ECF) micropumps. ECF is a functional fluid designed to be able to generate strong and active jet flow (ECF jetting) between anode and cathode in ECF when high DC voltage is applied. We have developed high power density ECF micropumps consisting of triangular prism and slit electrode pairs (TPSEs) fabricated by HARM. The traditional UV-LIGA technique for HARM is mainly divided into two approaches: (a) single thick layer and (b) multiple thin layers. Both methods have limitations—deformed molds in the former and misalignment between layers in the latter. Using the finite element method software COMSOL Multiphysics, we demonstrate that the deformed micro-molds critically impair the performance of ECF micropumps. In addition, we experimentally prove that the misalignment would easily trigger electric discharge in the ECF micropumps. To overcome these limitations, we conceive a new concept utilizing the seed electrode layer for electroforming as the UV shield and pattern photoresist (KMPR) by back UV exposure. The seed electrode layer should be composed of a non-transparent conductor (Au/Ti) for patterning and a transparent conductor (ITO) for wiring. Instead of ITO, we propose the concept of transparency-like electrodes comprised of thin metal line patterns. To verify this concept, KMPR layers with thicknesses of 70, 220, and 500 µ m are experimentally investigated. In the case of 500 µ m KMPR thickness, the concept of transparency-like electrode was partially proved. As a result, TPSEs with a height of 440 µ m were successfully fabricated. Characteristic experiments demonstrated that ECF micropumps (367 mW cm −3 ) fabricated by back UV achieved almost the same output power density as ECF micropumps (391 mW cm −3 ) fabricated by front UV. This paper proves that the
Silva, Everton F; Medeiros, Marco A; McBride, Alan J A; Matsunaga, Jim; Esteves, Gabriela S; Ramos, João G R; Santos, Cleiton S; Croda, Júlio; Homma, Akira; Dellagostin, Odir A; Haake, David A; Reis, Mitermayer G; Ko, Albert I
2007-08-14
Subunit vaccines are a potential intervention strategy against leptospirosis, which is a major public health problem in developing countries and a veterinary disease in livestock and companion animals worldwide. Leptospiral immunoglobulin-like (Lig) proteins are a family of surface-exposed determinants that have Ig-like repeat domains found in virulence factors such as intimin and invasin. We expressed fragments of the repeat domain regions of LigA and LigB from Leptospira interrogans serovar Copenhageni. Immunization of Golden Syrian hamsters with Lig fragments in Freund's adjuvant induced robust antibody responses against recombinant protein and native protein, as detected by ELISA and immunoblot, respectively. A single fragment, LigANI, which corresponds to the six carboxy-terminal Ig-like repeat domains of the LigA molecule, conferred immunoprotection against mortality (67-100%, P<0.05) in hamsters which received a lethal inoculum of L. interrogans serovar Copenhageni. However, immunization with this fragment did not confer sterilizing immunity. These findings indicate that the carboxy-terminal portion of LigA is an immunoprotective domain and may serve as a vaccine candidate for human and veterinary leptospirosis.
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Sala Garrido, Ramon
2009-01-01
Full Text Available RESUMEN En numerosas ocasiones se discute si una determinada liga es la mejor de Europa o si es otra, pero muchas veces ese concepto de “mejor” queda indefinido y se basa en elementos subjetivos o apreciaciones. El objetivo de este trabajo es comparar las ligas, española, inglesa e italiana, utilizando el rating ELO para poder determinar cual de las ligas es más homogénea en términos de equilibrio entre los equipos.El interés de una liga depende en gran parte de que exista incertidumbre en el resultado, es decir, lo que viene a denominarse como balance competitivo entre los equipos que la forman, ya que si no es así, la competición pierde interés en la medida en que el resultado es demasiado prfevisible, es decir, que los “buenos” equipos siempre vencen a los restantes, con lo que se perjudica al espectáculo y por tanto, las ganancias que reportan los ingresos, especialmente los televisivos.ABSTRACT It is often discussed whether a particular football league (soccer in America is the best league. However, the term 'best' is often indefinite and based on subjective elements. The aim of this study is to compare the Spanish, English and Italian leagues by using the ELO rating system to determine which league is more homogeneous in terms of balance between the teams. The level of interest in a league largely depends on the uncertainty of outcome or the competitive balance between the teams. If there is a competitive imbalance between the teams then the competition loses interest because the expected results coincide with the real results, namely the 'top' teams always win against the others. This can damage the spectacle, and therefore the earnings produced – especially in the case of television.
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Niangang Jiao
2018-05-01
Full Text Available With the increasing demand for high-resolution remote sensing images for mapping and monitoring the Earth’s environment, geometric positioning accuracy improvement plays a significant role in the image preprocessing step. Based on the statistical learning theory, we propose a new method to improve the geometric positioning accuracy without ground control points (GCPs. Multi-temporal images from the ZY-3 satellite are tested and the bias-compensated rational function model (RFM is applied as the block adjustment model in our experiment. An easy and stable weight strategy and the fast iterative shrinkage-thresholding (FIST algorithm which is widely used in the field of compressive sensing are improved and utilized to define the normal equation matrix and solve it. Then, the residual errors after traditional block adjustment are acquired and tested with the newly proposed inherent error compensation model based on statistical learning theory. The final results indicate that the geometric positioning accuracy of ZY-3 satellite imagery can be improved greatly with our proposed method.
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Luisa Quintino
2012-09-01
Full Text Available The demand of emerging joining techniques for shape memory alloys (SMA has become of great importance, as their functional properties namely shape memory effect (SME and superelasticity (SE present unique solutions for state-of-the-art applications. Welding of SMAs is a challenge due to the risk of reduced mechanical performance after laser processing. The wider application of these alloys in various sectors as aerospace, medical or electronic industry is hindered by the limitations in its processing. The need to weld SMAs to other materials is pressing for applications in the above referred sectors. In dissimilar joints the need to understand materials behavior is even more challenging since base materials have different physical properties leading to different heat flow, convection processes and residual stress distribution. The chemical composition across the weld pool varies and intermetallic compounds are formed. Research detailing the effects of laser processing on NiTi is essential to overcome many of these challenges. The objectives of the current study are to analyze the effects of laser welding in the weld shape of both similar and dissimilar joints of NiTi to stainless steel and titanium alloys.A procura de técnicas de ligação para ligas de memória de forma tem-se revetido de importância crescente, devido ao desenvolvimento de aplicações deste material com particulares propriedades de memória de forma e superelasticidade. A soldadura de ligas de memória de forma é um desafio devido ao risco de emporbrecimento das propriedades mecânicas depois do processamento laser. A aplicação alargarda destas ligas em vários sectores como o aeroespacial, medico ou electrónico é prejudicado pelas limitações de processamento. A necessidade de soldar ligas de memória de forma a outros materiais é premente para estes sectores. Em juntas dissimilares, o entendimento do comportamento dos materaias é um desafio ainda maior uma vez que
Figueira, Cláudio Pereira; Croda, Julio; Choy, Henry A; Haake, David A; Reis, Mitermayer G; Ko, Albert I; Picardeau, Mathieu
2011-06-09
In comparison to other bacterial pathogens, our knowledge of the molecular basis of the pathogenesis of leptospirosis is extremely limited. An improved understanding of leptospiral pathogenetic mechanisms requires reliable tools for functional genetic analysis. Leptospiral immunoglobulin-like (Lig) proteins are surface proteins found in pathogenic Leptospira, but not in saprophytes. Here, we describe a system for heterologous expression of the Leptospira interrogans genes ligA and ligB in the saprophyte Leptospira biflexa serovar Patoc. The genes encoding LigA and LigB under the control of a constitutive spirochaetal promoter were inserted into the L. biflexa replicative plasmid. We were able to demonstrate expression and surface localization of LigA and LigB in L. biflexa. We found that the expression of the lig genes significantly enhanced the ability of transformed L. biflexa to adhere in vitro to extracellular matrix components and cultured cells, suggesting the involvement of Lig proteins in cell adhesion. This work reports a complete description of the system we have developed for heterologous expression of pathogen-specific proteins in the saprophytic L. biflexa. We show that expression of LigA and LigB proteins from the pathogen confers a virulence-associated phenotype on L. biflexa, namely adhesion to eukaryotic cells and fibronectin in vitro. This study indicates that L. biflexa can serve as a surrogate host to characterize the role of key virulence factors of the causative agent of leptospirosis.
International Nuclear Information System (INIS)
Rohloff, F.; Brunen, E.
1981-08-01
A model is presented to calculate the γ-submersion dose of persons which are exposed to off-air plumes. This model integrates the dose contributions of the spacial volume elements, taking into account the wheather dependent extension of the plume as well as γ-absorption and scattering in air. For data evaluation an essentially improved code LIGA II has been developed, leading to a higher accuracy due to an adequate application of Gauss integrations in MACRO-technique. The short-term propagation factors are calculated for a grid distance of 10-160 km with a logarithmic scale and for a 5 degree angular grid. As is shown by a sensitivity analysis, the mean values of the short-term propagation factors within a sector can be obtained by a simple Simpson-integration. These calculations have been performed explicitly for 10 degree and 30 degree sectors. (orig.) [de
Pappas, Christopher J; Picardeau, Mathieu
2015-11-01
Leptospirosis is a zoonotic disease that affects ∼1 million people annually, with a mortality rate of >10%. Currently, there is an absence of effective genetic manipulation tools for targeted mutagenesis in pathogenic leptospires. Transcription activator-like effectors (TALEs) are a recently described group of repressors that modify transcriptional activity in prokaryotic and eukaryotic cells by directly binding to a targeted sequence within the host genome. To determine the applicability of TALEs within Leptospira spp., two TALE constructs were designed. First, a constitutively expressed TALE gene specific for the lacO-like region upstream of bgaL was trans inserted in the saprophyte Leptospira biflexa (the TALEβgal strain). Reverse transcriptase PCR (RT-PCR) analysis and enzymatic assays demonstrated that BgaL was not expressed in the TALEβgal strain. Second, to study the role of LigA and LigB in pathogenesis, a constitutively expressed TALE gene with specificity for the homologous promoter regions of ligA and ligB was cis inserted into the pathogen Leptospira interrogans (TALElig). LigA and LigB expression was studied by using three independent clones: TALElig1, TALElig2, and TALElig3. Immunoblot analysis of osmotically induced TALElig clones demonstrated 2- to 9-fold reductions in the expression levels of LigA and LigB, with the highest reductions being noted for TALElig1 and TALElig2, which were avirulent in vivo and nonrecoverable from animal tissues. This study reconfirms galactosidase activity in the saprophyte and suggests a role for LigA and LigB in pathogenesis. Collectively, this study demonstrates that TALEs are effective at reducing the expression of targeted genes within saprophytic and pathogenic strains of Leptospira spp., providing an additional genetic manipulation tool for this genus. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
Improving Accuracy of Dempster-Shafer Theory Based Anomaly Detection Systems
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Ling Zou
2014-07-01
Full Text Available While the Dempster-Shafer theory of evidence has been widely used in anomaly detection, there are some issues with them. Dempster-Shafer theory of evidence trusts evidences equally which does not hold in distributed-sensor ADS. Moreover, evidences are dependent with each other sometimes which will lead to false alert. We propose improving by incorporating two algorithms. Features selection algorithm employs Gaussian Graphical Models to discover correlation between some candidate features. A group of suitable ADS were selected to detect and detection result were send to the fusion engine. Information gain is applied to set weight for every feature on Weights estimated algorithm. A weighted Dempster-Shafer theory of evidence combined the detection results to achieve a better accuracy. We evaluate our detection prototype through a set of experiments that were conducted with standard benchmark Wisconsin Breast Cancer Dataset and real Internet traffic. Evaluations on the Wisconsin Breast Cancer Dataset show that our prototype can find the correlation in nine features and improve the detection rate without affecting the false positive rate. Evaluations on Internet traffic show that Weights estimated algorithm can improve the detection performance significantly.
Semião, Luís António Pereira
2010-01-01
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Civil - Estruturas e Geotecnia As ligas com memória de forma possuem duas propriedades singulares: a memória de forma e a superelasticidade. A memória de forma, é a capacidade do material recuperar a sua forma original através de uma variação de temperatura. A segunda propriedade destas ligas, e na qual esta dissertação se focará, é a superelasticidade....
Moessbauer studies of the LiAl sub(5-x) Fe sub(x) O8 and LiGa sub(5-x) Fe sub(x) O8 systems
International Nuclear Information System (INIS)
Barthem, V.M.T.S.; Maria Neto, J.; Souza Barros, F. de
1982-01-01
Comparative Moessbauer studies of the LiGa sub(5-x) Fe sub(x) O 8 and LiAl sub(5-x) Fe sub(x) O 8 systems are shown. The characteristics of the Moessbauer spectra, obtained with LiGa 5 O 8 samples with 0,1% of Fe 3+ , differ drastically from that observed with LiAl 5 O 8 with the same three-valent iron concentration. All these differences are related to the more covalent character of the gallium-oxygen binding, when compared with the aluminium-oxygen one. (L.C.) [pt
DEFF Research Database (Denmark)
Christensen, Rune; Hansen, Heine Anton; Vegge, Tejs
2015-01-01
Density functional theory (DFT) calculations have greatly contributed to the atomic level understanding of electrochemical reactions. However, in some cases, the accuracy can be prohibitively low for a detailed understanding of, e.g. reaction mechanisms. Two cases are examined here, i.e. the elec......Density functional theory (DFT) calculations have greatly contributed to the atomic level understanding of electrochemical reactions. However, in some cases, the accuracy can be prohibitively low for a detailed understanding of, e.g. reaction mechanisms. Two cases are examined here, i.......47 eV and 0.17 eV using metals as reference. The presented approach for error identification is expected to be applicable to a very broad range of systems. References: [1] A. A. Peterson, F. Abild-Pedersen, F. Studt, J. Rossmeisl, and J. K. Nørskov, Energy Environ. Sci., 3,1311 (2010) [2] F. Studt, F...
Parot, Jérémie; Susperregui, Nicolas; Rouaud, Vanessa; Dubois, Laurent; Anglade, Nathalie; Parlanti, Edith
2014-05-01
Marine mucilage is present in all oceans over the world, and in particular in the Mediterranean Sea and in the Pacific Ocean. Surface water warming and hydrodynamic processes can favor the coalescence of marine mucilage, large marine aggregates representing an ephemeral and extreme habitat for biota. DOM is a heterogeneous, complex mixture of compounds, including extracellular polymeric substances (EPS), with wide ranging chemical properties and it is well known to interact with pollutants and to affect their transport and their fate in aquatic environment. The LIGA French research program focuses on tracing colloidal dissolved organic matter (DOM) sources and cycling in the Bay of Biscay (South Western French coast). This ephemeral phenomenon (called "LIGA" in the South West of France) has been observed more than 750 times since 2010. It presents a great ecological impact on marine ecosystems and has been shown to be concomitant with the development of pathogen organisms. A one-year intensive survey of fluorescent DOM was undertaken. From April 2013 until May 2014, water samples were monthly collected from the Adour River (main fresh water inputs) and from 2 sites in the Bay of Biscay at 3 depths of the water column (surface water, at the maximum of chlorophyll-a, and deep water). Moreover, intensified samplings took place from the appearance of the phenomenon twice a week during 4 weeks. UV/visible absorbance and excitation emission matrix (EEM) fluorescence spectroscopy combined with PARAFAC and PCA analyses have been used to characterize colloidal DOM in the Bay of Biscay in order to estimate DOM sources as well as spatial and temporal variability of DOM properties. The preliminary results, obtained for about 70 samples of this survey, have already highlighted spatial and temporal variations of DOM optical properties and a peculiar fluorescent component (exc300nm/em338nm) was detected while the LIGA phenomenon arises. The appearance of this specific
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Isis Sebastião
2015-11-01
Full Text Available Resumo: O objetivo deste trabalho foi avaliar a toxicidade e a capacidade de ligação das proteínas Cry1Aa, Cry1Ab, Cry1Ac e Cry1Ca, de Bacillus thuringiensis, a receptores intestinais de Helicoverpa armigera. Realizou-se análise de ligação das proteínas ativadas às vesículas de membrana da microvilosidade apical (VMMA do intestino médio deH. armigera, além de ensaios de competição heteróloga para avaliar sua capacidade de ligação. Cry1Ac destacou-se como a proteína mais tóxica, seguida por Cry1Ab e Cry1Aa. A proteína Cry1Ca não foi tóxica às lagartas e, portanto, não foi possível determinar os seus parâmetros de toxicidade CL50 e CL90. As proteínas Cry1Aa, Cry1Ab e Cry1Ac são capazes de se ligar a um mesmo receptor nas membranas intestinais, o que aumenta o risco do desenvolvimento de resistência cruzada. Portanto, a utilização conjunta dessas proteínas deve ser evitada.
Zahavi, Arielle Y; Sabbagh, Mark A; Washburn, Dustin; Mazurka, Raegan; Bagby, R Michael; Strauss, John; Kennedy, James L; Ravindran, Arun; Harkness, Kate L
2016-01-01
Theory of mind-the ability to decode and reason about others' mental states-is a universal human skill and forms the basis of social cognition. Theory of mind accuracy is impaired in clinical conditions evidencing social impairment, including major depressive disorder. The current study is a preliminary investigation of the association of polymorphisms of the serotonin transporter (SLC6A4), dopamine transporter (DAT1), dopamine receptor D4 (DRD4), and catechol-O-methyl transferase (COMT) genes with theory of mind decoding in a sample of adults with major depression. Ninety-six young adults (38 depressed, 58 non-depressed) completed the 'Reading the Mind in the Eyes task' and a non-mentalistic control task. Genetic associations were only found for the depressed group. Specifically, superior accuracy in decoding mental states of a positive valence was seen in those homozygous for the long allele of the serotonin transporter gene, 9-allele carriers of DAT1, and long-allele carriers of DRD4. In contrast, superior accuracy in decoding mental states of a negative valence was seen in short-allele carriers of the serotonin transporter gene and 10/10 homozygotes of DAT1. Results are discussed in terms of their implications for integrating social cognitive and neurobiological models of etiology in major depression.
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Arielle Y Zahavi
Full Text Available Theory of mind-the ability to decode and reason about others' mental states-is a universal human skill and forms the basis of social cognition. Theory of mind accuracy is impaired in clinical conditions evidencing social impairment, including major depressive disorder. The current study is a preliminary investigation of the association of polymorphisms of the serotonin transporter (SLC6A4, dopamine transporter (DAT1, dopamine receptor D4 (DRD4, and catechol-O-methyl transferase (COMT genes with theory of mind decoding in a sample of adults with major depression. Ninety-six young adults (38 depressed, 58 non-depressed completed the 'Reading the Mind in the Eyes task' and a non-mentalistic control task. Genetic associations were only found for the depressed group. Specifically, superior accuracy in decoding mental states of a positive valence was seen in those homozygous for the long allele of the serotonin transporter gene, 9-allele carriers of DAT1, and long-allele carriers of DRD4. In contrast, superior accuracy in decoding mental states of a negative valence was seen in short-allele carriers of the serotonin transporter gene and 10/10 homozygotes of DAT1. Results are discussed in terms of their implications for integrating social cognitive and neurobiological models of etiology in major depression.
Moreira, Edna Fernandes, 1985-
2012-01-01
Tese de mestrado em Química Tecnológica, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2012 O presente trabalho teve como objetivo o estudo da influência de pré-tratamentos superficiais no desempenho à corrosão de revestimentos híbridos de sol-gel para a proteção de uma liga de alumínio frequentemente utilizada na construção civil. Para atingir esse objetivo foram aplicados diversos pré-tratamentos à liga de alumínio EN AW-6063. Os pré-tratamentos adotados consist...
Avaliação da fundibilidade de uma liga de cobalto-cromo
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CARREIRO Adriana da Fonte Porto
1999-01-01
Full Text Available Neste trabalho propusemo-nos a avaliar a fundibilidade de uma liga de cobalto-cromo (VERA-PDI em função da utilização de três revestimentos: Knebel (aglutinado por sílica, Termocast e Wirovest (aglutinados por fosfato e duas temperaturas de aquecimento para o molde (900°C e 950°C. Para a execução do teste foi utilizado o método descrito por HINMAN et al.9 (1985. O método de fundição foi o de cera perdida sob chama de gás-oxigênio. Os dados obtidos foram submetidos a análise estatística e demonstraram não haver diferença estatisticamente significante para os revestimentos Knebel e Wirovest, e diferença estatisticamente significante ao nível de 0,1% para o revestimento Termocast quando da variação da temperatura de aquecimento do molde. Quando analisamos os revestimentos sob temperatura do molde de 900°C verificamos diferença estatisticamente significante entre Knebel e Termocast e Knebel e Wirovest ao nível de 0,1%, e diferença entre Termocast e Wirovest ao nível de 5%. Para a temperatura de 950°C houve diferença estatisticamente significante ao nível de 0,1% entre todos os revestimentos. Dentro dos parâmetros utilizados neste estudo pudemos concluir que, para a liga VERA-PDI, a utilização do revestimento Knebel e temperatura de aquecimento do molde de 950°C proporcionaram melhores resultados quanto à fundibilidade.
Desempenho de um filme livre de cromo na proteção contra a corrosão de ligas de alumínio 2024.
Mayra Rúbia Silva Castro
2001-01-01
Este trabalho propõe o uso de um filme preparado a partir de solução aquosa alcalina contendo íons de lítio, borato e alumínio, no sentido de inibir a corrosão de ligas de alumínio de uso aeronáutico, buscando sempre comparações com filmes de sais de cromo, atualmente utilizados. Os filmes foram obtidos por dip coating (5 minutos) e por polarização anódica (5 e 45 minutos) de ligas de alumínio 2024-T3 na solução aquosa alcalina contendo íons de lítio, borato e alumínio. Foram feitas micrograf...
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Rodrigo Freitas Guimarães
2010-12-01
Full Text Available Aços Cr-Mo são usados na indústria do petróleo em aplicações com óleos crus ricos em compostos sulfurosos. Aços comerciais como 2.5Cr1Mo ou 9Cr1Mo têm se mostrado ineficientes em consequência de altos índices de corrosão naftênica. Uma estratégia para resolver este problema é o aumento do teor de molibdênio destes aços. Neste trabalho foi estudado o efeito do aumento do teor de molibdênio na microestrutura de ligas Fe-9Cr-xMo, solubilizadas e soldadas. Foram levantados os diagramas de fases com auxílio de um programa comercial para verificar as possíveis fases a serem formadas e identificar os problemas de soldagem. A microestrutura das ligas solubilizadas foi analisada por microscopia óptica e EBSD, além da medição da dureza. Foram realizadas soldagens autógenas para verificar o efeito do aporte térmico na microestrutura e na dureza das ligas. O aumento do teor de molibdênio resultou no aumento da dureza das ligas. A análise microestrutural das ligas soldadas apresentou uma particularidade para a liga com menor teor de molibdênio, a presença de martensita. Já as ligas com maior teor de molibdênio apresentaram uma microestrutura completamente ferrítica. A formação de martensita pode ser um problema na solda da liga com menor teor de molibdênio, uma vez que a mesma pode causar perdas nas propriedades mecânicas comprometendo sua aplicação.Cr-Mo steels are used in the petroleum industry in applications with crude oils rich in sulfur compounds. 2.5Cr1Mo or 9Cr1Mo do not resist to operating conditions when in contact with crude oils. The increasing of molybdenum content can improve the corrosion resistance of these alloys. This paper studied the effect of increased concentration of molybdenum in the microstructure of Fe-9Cr-xMo alloys, annealed and welded. Phase diagrams were built with the aid of commercial program to check the possible phases to be formed and to identify the problems of welding. Analyses were
Molina, Sergio L; Stodden, David F
2018-04-01
This study examined variability in throwing speed and spatial error to test the prediction of an inverted-U function (i.e., impulse-variability [IV] theory) and the speed-accuracy trade-off. Forty-five 9- to 11-year-old children were instructed to throw at a specified percentage of maximum speed (45%, 65%, 85%, and 100%) and hit the wall target. Results indicated no statistically significant differences in variable error across the target conditions (p = .72), failing to support the inverted-U hypothesis. Spatial accuracy results indicated no statistically significant differences with mean radial error (p = .18), centroid radial error (p = .13), and bivariate variable error (p = .08) also failing to support the speed-accuracy trade-off in overarm throwing. As neither throwing performance variability nor accuracy changed across percentages of maximum speed in this sample of children as well as in a previous adult sample, current policy and practices of practitioners may need to be reevaluated.
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Maria Júlia Xavier Belém
2015-12-01
Full Text Available Resumo Revestimentos são crescentemente utilizados como alternativa de engenharia em projetos avançados. Diversas técnicas e processos estão disponíveis para a aplicação de revestimentos, dependendo da condição específica a que se destinam. Revestimentos para barreira térmica, conhecidos como TBC, fazem parte de uma série especial de revestimentos metal-cerâmicos com tradicional utilização na indústria aeronáutica e crescente aplicação nas indústrias automotiva e de turbinas industriais. Um dos maiores problemas dos TBCs é sua degradação devido à oxidação em alta temperatura da camada de ligação, levando à falha do revestimento por desplacamento. O presente estudo investiga e compara o comportamento de oxidação da camada de ligação de revestimentos para barreira térmica (TBC, tendo como material a liga NiAl, que é uma liga bastante utilizada devido a suas características em altas temperaturas e por ter uma boa adesão em vários substratos. A camada de ligação foi aplicada em um substrato de Aço ABNT 1020 pelo processo Flame Spray (Aspersão a chama. Para a realização dos testes de oxidação isotérmica, o forno utilizado foi regulado a uma temperatura de 1000°C em atmosfera de ar estático, com exposição das amostras por 24, 48, 96 horas e o resfriamento feito em ar atmosférico à temperatura ambiente. A análise do óxido crescido termicamente (TGO – Thermally Grown Oxide em cada amostra foi feita relacionando os tempos de exposição, avaliando a taxa de óxidos por meio de medições de ganho de massa das amostras com revestimentos oxidados e análises por Microscopia Eletrônica de Varredura e Microscopia Ótica.
EFECTO DE LA GEOMETRÍA DEL MOLDE EN EL ELECTROFORMADO DE MICROPIEZAS POR UV-LIGA
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JUAN C. GAVIRIA VILLA
2009-01-01
Full Text Available UV-LIGA es una técnica versátil que permite la fabricación de piezas metálicas con alta relación de aspecto (alto/ancho mediante la combinación del procesamiento fotolitográfico de un polímero y la electroformación de un metal al interior de las cavidades grabadas en el polímero. Esta técnica de bajo costo es empleada en una gran variedad de áreas que comprenden la microfluídica, la óptica, la instrumentación, el moldeado de plásticos y las telecomunicaciones, entre otras. Para aproximar a Colombia a estas tecnologías modernas de procesamiento de materiales, el Grupo de Ciencia y Tecnología de Materiales ha iniciado un proceso de apropiación de técnicas de microfabricación, específicamente, este artículo presenta los resultados de la implementación de la técnica UV-LIGA para la fabricación de micropiezas de Níquel y examina los efectos de la geometría del molde en la velocidad de crecimiento e integridad de los depósitos obtenidos, parámetros que sonimportantes para conseguir la fabricación de piezas micrométricas complejas que den origen a dispositivos con aplicaciones comerciales.
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José Roberto Franco Reis
2000-06-01
Full Text Available Este artigo propõe-se a discutir as propostas de intervenção na problemática infantil apresentadas pela Liga Brasileira de Higiene Mental (LBHM, instituição criada no começo da década de 1920 que reunia a elite da psiquiatria brasileira, mas também alguns médicos e intelectuais em geral. Fundada num momento de afirmação, no campo psiquiátrico, da perspectiva preventiva, a LBHM vai incorporar ao seu arsenal teórico os temas básicos da higiene mental e da eugenia, tendo em vista o seu objetivo maior de colaborar no "saneamento racial" brasileiro. Assim, é a partir desse objetivo e vendo na criança um "pré-cidadão", "peça fundamental do homem do futuro", que os psiquiatras da liga incluem a questão infantil nos seus projetos, passando a considerar imperiosa a necessidade de cuidados desde a mais tenra idade.Created in the early 1920s, at a moment when the country’s psychiatric field was embracing the preventive outlook, the Liga Brasileira de Higiene Mental included within its members the elite of Brazilian psychiatry, along with a number of physicians and intellectuals. The article discusses the institution’s proposals for intervention among children. The league ended up incorporating into its theoretical arsenal the basic themes of mental hygiene and eugenics as part of its general goal of collaborating in Brazil’s process of "racial sanitation". With this objective in mind, and viewing the child as a "pre-citizen" who is a "fundamental part within the man of the future", league members included the children’s issue in their projects and saw an imperative need for mental health care from early ages on.
LA LIGA DE DAMAS CHILENAS: DE LA CRUZADA MORALIZADORA AL SINDICALISMO FEMENINO CATOLICO, 1912-1918
ROBLES PARADA, ANDREA ISOLINA
2013-01-01
INTRODUCCION A comienzos del siglo XX la representación de la mujer de la clase alta chilena se vio envuelta en la convergencia entre imaginarios tradicionales y experiencias nuevas. A partir de este supuesto estudiamos la particularidad de los cambios que suscitó la modernidad en las mujeres católicas de la elite que organizaron La Liga de Damas Chilenas. A través de esta asociación, fundada en 1912, las mujeres católicas comenzaron a int...
Minto, Thiago Alexandre [UNESP
2016-01-01
O estudo do comportamento em fadiga e corrosão dos materiais é de extrema importância para a indústria aeronáutica, considerando componentes estruturais que estão submetidos a carregamentos cíclicos constantemente. As ligas de alumínio desempenham papel fundamental nesse ramo, principalmente as ligas da série 7xxx de alta resistência. Como esses componentes também operam em ambientes marítimos, os revestimentos anticorrosivos são utilizados como proteção. Dos processos de revestimentos dispon...
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Suzana Cristina Marucci
2015-08-01
Full Text Available Resumo:O objetivo deste trabalho foi avaliar a toxicidade de novas proteínas Vip3Aa e sua capacidade de ligação a vesículas de membrana da microvilosidade apical (VMMA do intestino de lagartas neonatas de Spodoptera frugiperda, Anticarsia gemmatalise Heliothis virescens. Proteínas expressas pelos genes vip3Aa42 e vip3Aa43 mostraram-se tóxicas a S. frugiperda (CL50 de 78,2 e 113 ng cm-2, respectivamente e A. gemmatalis(CL50 de 239,2 e 57,5 ng cm-2, respectivamente, e pouco tóxicas a H. virescens (CL50>5.000 ng cm-2. Os ensaios de ligação às VMMA mostraram que as proteínas unem-se de forma efetiva aos receptores nas vesículas das espécies avaliadas, mas essa capacidade de ligação somente é efetiva na ativação da toxicidade para as populações avaliadas de S. frugiperdae A. gemmatalis.
Improving the accuracy of Møller-Plesset perturbation theory with neural networks
McGibbon, Robert T.; Taube, Andrew G.; Donchev, Alexander G.; Siva, Karthik; Hernández, Felipe; Hargus, Cory; Law, Ka-Hei; Klepeis, John L.; Shaw, David E.
2017-10-01
Noncovalent interactions are of fundamental importance across the disciplines of chemistry, materials science, and biology. Quantum chemical calculations on noncovalently bound complexes, which allow for the quantification of properties such as binding energies and geometries, play an essential role in advancing our understanding of, and building models for, a vast array of complex processes involving molecular association or self-assembly. Because of its relatively modest computational cost, second-order Møller-Plesset perturbation (MP2) theory is one of the most widely used methods in quantum chemistry for studying noncovalent interactions. MP2 is, however, plagued by serious errors due to its incomplete treatment of electron correlation, especially when modeling van der Waals interactions and π-stacked complexes. Here we present spin-network-scaled MP2 (SNS-MP2), a new semi-empirical MP2-based method for dimer interaction-energy calculations. To correct for errors in MP2, SNS-MP2 uses quantum chemical features of the complex under study in conjunction with a neural network to reweight terms appearing in the total MP2 interaction energy. The method has been trained on a new data set consisting of over 200 000 complete basis set (CBS)-extrapolated coupled-cluster interaction energies, which are considered the gold standard for chemical accuracy. SNS-MP2 predicts gold-standard binding energies of unseen test compounds with a mean absolute error of 0.04 kcal mol-1 (root-mean-square error 0.09 kcal mol-1), a 6- to 7-fold improvement over MP2. To the best of our knowledge, its accuracy exceeds that of all extant density functional theory- and wavefunction-based methods of similar computational cost, and is very close to the intrinsic accuracy of our benchmark coupled-cluster methodology itself. Furthermore, SNS-MP2 provides reliable per-conformation confidence intervals on the predicted interaction energies, a feature not available from any alternative method.
Piccinni, Giuseppe; Pasculli, Alessandro; D'Ambrosio, Erasmina; Gurrado, Angela; Lissidini, Germana; Testini, Mario
2013-09-01
Pancreatoduodenectomy is an exceptional procedure that requires an extensive dissection of the supramesocolic region extended to the first jejunal limb. Lymphadenectomy, required for cancer, increases the dissection surface. The extensive preparation of the area is traditionally conducted with bipolar ormonopolar instruments, while clips, ligatures, and sutures are used for haemostasis. LigaSure™ vessel sealing(LSVS; Valleylab, Boulder, CO) is a technology that obtains vessel closure by using the body's own collagen and elastin to create a permanent fusion zone. This is obtained by a combination of forceps pressure and radio frequency. This effect has been improved by the introduction of the Force Triad™ (Valleylab, Boulder,CO) energy platform, controlled by TissueFect™ (Valleylab, Boulder, CO) sensing technology. With this device, the surgeon is able to fuse vessels up to 7 mm, lymphatics, tissue bundles, and pulmonary vasculature in a fast-seal cycle of almost 4 seconds. In our daily practice of open surgery we observe a rapid improvement of abdominal drainage output with a drastic reduction of protein loss. Its practical significance is, in our opinion, that we obtain a rapid recovery of normal serum protein levels with a low number of blood/plasmasac transfusions and a real improvement of anastomosis healing. Moreover, the efficacy and the speed of work of the device allow us to reduce the operating time significantly but safely. We performed a retrospective analysis of the data of 20 pancreatic resections conducted both with traditional dissection and with the Liga-Sure Impact device with Force Triad platform in order to verify whether observed data were real. Our clinical results show that the use of the LigaSure Impact device with Force Triad energy platform is really useful in open surgery to save operating time, number of postoperative days, and hemoderivate administration.
Forjamento da liga AA 2011 no estado semi-solido : estudo do processo e do produto
Maximino Manuel Montel Rovira
2001-01-01
Resumo: O trabalho apresenta uma análise da aplicação da tecnologia de processamento de materiais no estado semi-sólido, no foIjamento da liga de alumínio AA2011. Inicialmente foi estudada a influência da temperatura de reofundição na qualidade de pastas semi-sólidas obtidas pelo método de fusão parcial controlada de estruturas refinadas (FPCER). Foram sistematizados testes de tratamento térmico a quatro diferentes temperaturas (888,893,898 e 903 K), por tempo de 10 min para globularização da...
Oposição à aquisição da nacionalidade: a inexistência de ligação efectiva à comunidade nacional
Costa, Paulo Manuel
2012-01-01
Neste artigo fazemos uma breve análise sobre a jurisprudência portuguesa em matéria de nacionalidade, em especial quanto à verificação da existência de uma ligação efectiva a comunidade nacional dos candidatos à aquisição da nacionalidade.
Effects of accuracy motivation and anchoring on metacomprehension judgment and accuracy.
Zhao, Qin
2012-01-01
The current research investigates how accuracy motivation impacts anchoring and adjustment in metacomprehension judgment and how accuracy motivation and anchoring affect metacomprehension accuracy. Participants were randomly assigned to one of six conditions produced by the between-subjects factorial design involving accuracy motivation (incentive or no) and peer performance anchor (95%, 55%, or no). Two studies showed that accuracy motivation did not impact anchoring bias, but the adjustment-from-anchor process occurred. Accuracy incentive increased anchor-judgment gap for the 95% anchor but not for the 55% anchor, which induced less certainty about the direction of adjustment. The findings offer support to the integrative theory of anchoring. Additionally, the two studies revealed a "power struggle" between accuracy motivation and anchoring in influencing metacomprehension accuracy. Accuracy motivation could improve metacomprehension accuracy in spite of anchoring effect, but if anchoring effect is too strong, it could overpower the motivation effect. The implications of the findings were discussed.
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C. Lago
2010-09-01
Full Text Available
RESUMEN
El objetivo de este trabajo es estudiar cuál es el efecto del rendimiento y la suerte sobre el resultado alcanzado por los equipos en competiciones oficiales de fútbol con diferentes formatos de competición. La muestra consiste en los 190 partidos disputados en la primera vuelta de la Liga Española de Fútbol de la temporada 2006-2007, los 64 partidos disputados en el Campeonato Mundia1 de Fútbol de Alemania 2006 y los 125 partidos de la Liga de Campeones de la temporada 2005-2006. Mediante una estimación basada en el análisis de regresión lineal y en la comparación de medias se concluye que en las competiciones disputadas bajo el formato de liga (la Liga Española, la primera fase de la Liga de Campeones y la primera fase del Campeonato del Mundo el azar puede tener relevancia para explicar el resultado de los equipos en un único partido o, a lo sumo, en un número muy limitado de ellos, pero que a partir de cierta cantidad de encuentros el rendimiento es determinante para dar cuenta de los puntos que alcanzan los conjuntos. En las competiciones disputadas bajo el formato de eliminación directa (la segunda fase de la Liga de Campeones y la segunda fase del Campeonato del Mundo, no se han encontrado diferencias estadísticamente significativas en el rendimiento de los equipos ganadores y perdedores. El azar puede ser un factor muy importante que influye en el resultado de las competiciones que se disputan bajo el formato de eliminación directa.
Palabras clave: Formato de competición, rendimiento, azar, fútbol
ABSTRACT
The aim of this study is to analyze the influence of performance and chance
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Ana Maria Barros Pires
2012-12-01
Full Text Available As representações que a sociedade associa à profissão de enfermagem e à enfermeira, muitas vezes contraditórias, persistem no imaginário individual e coletivo e pouco têm a ver com a evolução verificada no âmbito do exercício profissional, do ensino e da academia. As imagens associadas à enfermeira e à enfermagem inscrevem-se na memória dum passado mais ou menos longínquo e poderão ter uma justificação histórica, social e cultural. Desvendar do modo como as representações sociais associadas à enfermeira e à enfermagem se constituíram no passado poderá permitir-nos recriar, no presente, o percurso da nossa identidade profissional e compreender como, enquanto grupo social, produzimos, consumimos, divulgamos e assumimos imagens que definem essa própria identidade. Propomo-nos neste artigo dar a conhecer como a Liga Republicana das Mulheres Portuguesas (LRMP, no início do século XX, criou uma imagem positiva da enfermagem, desenvolvendo um discurso elogioso da profissão captando o interesse das mulheres para uma “profissão digna” que lhes possibilitaria a independência económica em caso de abandono ou viuvez. Utilizaremos um conjunto de artigos publicados na imprensa oficial da Liga: A Mulher e A Criança e A Madrugada dado que a imprensa foi uma importante forma de divulgação e doutrinação das ideias feministas.Las representaciones que la sociedad asocia con la profesión de enfermería y a la enfermera, a menudo contradictorias, persisten en el imaginario individual y colectivo y tienen poco que ver con la evolución en el campo profesional, la educación y la academia. Las imágenes asociadas con la enfermera y la enfermería están registradas en la memoria de un pasado más o menos lejano y pueden tener una justificación histórica, cultural y social. Descubrir cómo las representaciones asociadas con la enfermería y la enfermera se constituyeron nos permitirá recrear el curso de nuestra identidad
Mechanisms of fatigue in LIGA Ni MEMS thin films
International Nuclear Information System (INIS)
Yang, Y.; Imasogie, B.I.; Allameh, S.M.; Boyce, B.; Lian, K.; Lou, J.; Soboyejo, W.O.
2007-01-01
This paper presents the results of an experimental study of the mechanisms of fatigue in LIGA Ni micro-electro-mechanical systems (MEMS) thin films with micro-scale columnar and nano-scale equiaxed grains. Stress-life behavior is reported for films with thicknesses of 70 and 270 μm. The stress-life data are compared with previously reported data for Ni MEMS films and bulk Ni. The films with the nano-scale grains (15 nm average grain size) are shown to have higher strength and fatigue resistance (stress-life data) than those with columnar grain structures. The thicker films (with a columnar microstructure) are also shown to have comparable fatigue life to annealed Ni, while the thinner films (with a columnar microstructure) have comparable fatigue life to wrought Ni. The underlying mechanisms of crack nucleation and growth are elucidated via scanning and transmission electron microscopy. These reveal the formation of slip bands and surface oxides and crystallographic surface/sub-surface crack nucleation and growth in the films with the columnar structures. Surface and corner crack nucleations (from pre-existing defects) are observed in the nanostructured films. The implications of the results are discussed for the analyses of fatigue in nickel MEMS structures
Evaluating measurement accuracy a practical approach
Rabinovich, Semyon G
2017-01-01
This book presents a systematic and comprehensive exposition of the theory of measurement accuracy and provides solutions that fill significant and long-standing gaps in the classical theory. It eliminates the shortcomings of the classical theory by including methods for estimating accuracy of single measurements, the most common type of measurement. The book also develops methods of reduction and enumeration for indirect measurements, which do not require Taylor series and produce a precise solution to this problem. It produces grounded methods and recommendations for summation of errors. The monograph also analyzes and critiques two foundation metrological documents, the International Vocabulary of Metrology (VIM) and the Guide to the Expression of Uncertainty in Measurement (GUM), and discusses directions for their revision. This new edition adds a step-by-step guide on how to evaluate measurement accuracy and recommendations on how to calculate systematic error of multiple measurements. There is also an e...
Attacks of the soccer teams participating in the champions league and the Serbian super liga
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Janković Aleksandar
2016-01-01
Full Text Available The area of tactics in soccer game is of particular importance for modern soccer development. The analysis and improvement of spatio-temporal indicators as well as the game principles related to tactics may be crucial to the achievement of competitive results. This study is aimed at comparing tactical manifestations of the teams competing in the top quality European club competition, the Champions League, and the best Serbian soccer championship by analyzing competitive activity. The results of the conducted research were obtained by observing an overall of 20 randomly selected matches, 10 of the Champions League (CL and 10 of the Serbian Super Liga (SSL, which is a sufficient number of matches for making conclusions about the competitions respectively. In the previously designed observing protocol, using a method of notation, we analyzed all the attacks completed by shooting at the opponent's goal. The structure of successfully realized attacks was assessed on the basis of: accuracy, types of realized offensive actions; area of starting the action, manner of realization of passes completed (assists and distance from the goal from which a shot on goal was executed. The study showed that there are certain common characteristics, but also there are differences in the structure of successfully realized attacks between the two analyzed competitions. The teams of the CL competition had significantly greater number of effective attacks per match (p = 0. 006, they realized their offensive activities with slightly greater number of players (p = 0.002 and number of passes (p = 0.000, whereas there are no significant differences in the area of starting successful attacks, the manner of realization of assists and distance from which shots on goal were executed. The study results may define certain guidelines in training technology when preparing the teams of the SSL competition for taking part in the European soccer cups.
Test Expectancy Affects Metacomprehension Accuracy
Thiede, Keith W.; Wiley, Jennifer; Griffin, Thomas D.
2011-01-01
Background: Theory suggests that the accuracy of metacognitive monitoring is affected by the cues used to judge learning. Researchers have improved monitoring accuracy by directing attention to more appropriate cues; however, this is the first study to more directly point students to more appropriate cues using instructions regarding tests and…
Liu, C; Liu, J; Yao, Y X; Wu, P; Wang, C Z; Ho, K M
2016-10-11
We recently proposed the correlation matrix renormalization (CMR) theory to treat the electronic correlation effects [Phys. Rev. B 2014, 89, 045131 and Sci. Rep. 2015, 5, 13478] in ground state total energy calculations of molecular systems using the Gutzwiller variational wave function (GWF). By adopting a number of approximations, the computational effort of the CMR can be reduced to a level similar to Hartree-Fock calculations. This paper reports our recent progress in minimizing the error originating from some of these approximations. We introduce a novel sum-rule correction to obtain a more accurate description of the intersite electron correlation effects in total energy calculations. Benchmark calculations are performed on a set of molecules to show the reasonable accuracy of the method.
Silva, Éverton F.; Medeiros, Marco A.; McBride, Alan J. A.; Matsunaga, Jim; Esteves, Gabriela S.; Ramos, João G. R.; Santos, Cleiton S.; Croda, Júlio; Homma, Akira; Dellagostin, Odir A.; Haake, David A.; Reis, Mitermayer G.; Ko, Albert I.
2007-01-01
Subunit vaccines are a potential intervention strategy against leptospirosis, which is a major public health problem in developing countries and a veterinary disease in livestock and companion animals worldwide. Leptospiral immunoglobulin-like (Lig) proteins are a family of surface-exposed determinants that have Ig-like repeat domains found in virulence factors such as intimin and invasin. We expressed fragments of the repeat domain regions of LigA and LigB from Leptospira interrogans serovar...
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André L. Christoforo
2011-10-01
Full Text Available Trusses are structural systems commonly used in projects, being employed mainly in roof structures, present in most rural buildings. The design of trusses, as well as other structural systems, requires the determination of displacements, strains and stresses. However, the project is developed from an ideal model of calculation, considering free rotation between the elements of a connection. This paper presents a computer program for the analysis of bidimensional wooden trusses with connections formed with two screws per node. The formulation is based on the flexibility method, taking into account the influence of the effect of semi-rigid connections formed by two screws. An example of a structure is presented and analyzed by the program developed here, highlighting the importance of behavior analysis on semi-rigid connections.Treliças são sistemas estruturais comumente utilizados em projetos, empregadas principalmente em estruturas de cobertura, presentes na maioria das construções rurais. O dimensionamento de treliças, assim como o de outros sistemas estruturais, requer a determinação dos deslocamentos, esforços, tensões e deformações atuantes em seus elementos constituintes. O cálculo é desenvolvido com base em um modelo ideal, considerando-se o giro livre entre os elementos componentes de uma ligação. Este trabalho objetiva apresentar um programa computacional destinado à análise de treliças planas de madeira com ligações formadas com dois parafusos por nó. A formulação é fundamentada no Método da Flexibilidade, levando-se em consideração a influência do efeito semirrígido das ligações formadas por dois parafusos. Um exemplo de estrutura auxiliar de cobertura é apresentado e analisado pelo programa desenvolvido, evidenciando-se a importância da análise do comportamento semirrígido sobre as ligações.
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J. S. Pimenta
2012-06-01
Full Text Available Zircônia tetragonal estabilizada com ítria foi mecanicamente metalizada com titânio e a condição de molhamento avaliada com as ligas convencionais Ag-28Cu e Au-18Ni. Estas dissolveram o revestimento de titânio para uma completa distribuição deste metal ativo na superfície cerâmica, gerando uma liga ativa in situ e possibilitando adequadas ligações químicas ao metal base na temperatura de união. Os melhores resultados de molhamento foram selecionados para brasagem indireta em forno de alto-vácuo nas juntas ZrO2/Ti-6Al-4V. Testes de detecção de vazamento de gás hélio foram realizados na interface de união das juntas; amostras removidas na seção transversal de juntas estanques foram examinadas por técnicas de análise microestrutural. Formou-se uma camada escura adjacente à cerâmica metalizada, responsável pelo molhamento ocasionado pela liga Ag-28Cu. Entretanto, o uso da liga Au-18Ni resultou em precipitação de intermetálicos e microtrincamento interfacial. Perfis de microdureza através da interface resultante até onde a zircônia mostrou típico escurecimento não indicaram alternância significativa entre medições consecutivas; os resultados dos ensaios de resistência mecânica à flexão-3p foram considerados satisfatórios.Yttria tetragonal zirconia polycrystal was mechanically metallized with titanium and the wetting behavior on the ceramic surface was analyzed using the conventional fillers Ag-28Cu and Au-18Ni. These alloys had dissolved the active metal coating, which acts to zirconia reduction on its surface and promoting suitable chemical bonding to the metallic member. Better wetting results were selected for indirect brazing in a high-vacuum furnace for ZrO2/Ti-6Al-4V simple butt joints. Helium gas leak detection was made at the joints interface; samples were removed from the tight joints cross-section and examined by microstructural analysis techniques and EDX analysis. There was formation of a dark
Estudo do comportamento sísmico de ligações reforçadas em edifícios Pombalinos e Gaioleiros
Sá, Bruno Filipe Pereira de
2012-01-01
Dissertação de mestrado integrado em Engenharia Civil O trabalho apresentado nesta dissertação foi desenvolvido no departamento de Engenharia Civil da Universidade do Minho. Este trabalho, de caráter experimental, pretende ser uma contribuição para melhor compreender o comportamento das ligações, reforçadas e não reforçadas, nos edifícios históricos de alvenaria Pombalinos e Gaioleiros, sob ações cíclicas que influenciam a vulnerabilidade sísmica. Os ensaios realizados envol...
Correa-Mesa, Juan Felipe; Rodríguez-Camacho, Diego Fabricio; Camargo-Rojas, Diana Alexandra; Correa-Morales, Juan Carlos
2016-01-01
Resumen Introducción. En lucha se presentan eventos que pueden generar alteraciones físicas, como caídas, contactos en el suelo, levantamientos, arqueamientos, entre otros. Objetivo. Estimar la prevalencia de lesiones y factores correlacionados en deportistas practicantes de lucha olímpica. Materiales y métodos. Estudio observacional de tipo correlacional y diseño transversal. Participaron 29 deportistas pertenecientes a la Liga de Bogotá. Resultados. En el último año, 15 deportistas ...
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Carlos Henrique Ferreira Camargo
2014-11-01
Full Text Available A Liga Acadêmica de Neurociências é um projeto extensionista composto por um grupo de estudantes, coordenado por professores da UEPG – Universidade Estadual de Ponta Grossa, dedicados a se aprofundarem nas ciências neurológicas, ampliarem o conhecimento nas principais doenças da área das neurociências e atenderem as demandas da população sobre o tema. Os membros são designados por meio de um processo seletivo que ocorre anualmente. A liga abrange as três modalidades clássicas de aprendizado: Ensino, Pesquisa e Extensão. Na área de Ensino, há reuniões semanais sobre um assunto preestabelecido nas áreas de neurologia clínica, psiquiatria e neurocirurgia. Na Pesquisa, os alunos que apresentam interesse realizam projeto em iniciação científica sob a coordenação dos professores responsáveis pela liga. Por fim, na Extensão, os acadêmicos acompanham atendimentos nos ambulatórios de Neurologia do HURCG – Hospital Universitário Regional dos Campos Gerais – e praticam atividades direcionadas para a população, como palestras sobre AVC (Acidente Vascular Cerebral. A cada ano, novas ideias têm sido implantadas para enriquecer o conhecimento dos acadêmicos. Palavras-chave: Instituições Acadêmicas, Neurociências, Educação Superior, Educação de Graduação em Medicina, Relações Comunidade-Instituição. The Neuroscience League: the academic complementation at neurological studies based on actions of education, research and extension Abstract: The Neuroscience Academic League is a university extension project composed of students supervised by professors from UEPG (Universidade Estadual de Ponta Grossa, Paraná, Brazil. This group is dedicated to delving into neurosciences, expanding their knowledge in the fields of major neuroscience-related diseases, as well as meeting the demands of the population on the subject. The members of the project are appointed through a selection process which takes place annually
Avaliação de Revestimentos de Liga de Níquel 625 Depositados pelo Processo Eletroescória
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Soraia Simões Sandes
Full Text Available Resumo A aplicação de revestimentos de ligas de níquel é comumente realizada na indústria de petróleo e gás para aumento da vida de equipamentos em ambientes agressivos, dado que este procedimento melhora a resistência à corrosão, sem um aumento significativo do custo de produção quando comparado com equipamentos maciços fabricados com outras ligas. Normalmente, as juntas são soldadas pelos processos de eletrodos revestidos, MIG/MAG ou TIG. Neste aspecto, o processo eletroescória realiza deposições com elevada energia de soldagem e baixa diluição, podendo ser uma opção interessante, uma vez que proporciona uma elevada produtividade, permitindo a soldagem com aplicação de apenas uma camada. O presente trabalho avalia propriedades mecânicas, microestruturais e de corrosão de revestimentos de liga de níquel 625 depositada em aço carbono ASTM A516 Grau 70 pelo processo eletroescória, tanto na condição como soldado quanto tratado termicamente. A deposição foi realizada com uma e duas camadas sobre chapas de dimensão 50x400x400 mm, na posição plana e energia de soldagem média de 11,7 kJ/mm. Após a soldagem realizou-se tratamento térmico a 620°C por 10 horas, sendo esta condição comparada ao estado de como soldado. Os ensaios de dobramento não indicaram evidências de defeitos. A avaliação microestrutural realizada por microscopia ótica (MO, eletrônica de varredura (MEV e eletrônica de transmissão (MET mostrou uma microestrutura austenítica para o depósito com pequena fração volumétrica de fases secundárias e o tratamento térmico de alívio de tensões não promoveu mudanças significativas nas propriedades. Na região de grãos grosseiros da zona termicamente afetada (RGGZTA foi observada a ocorrência de ferrita pró-eutetóide, perlita e bainita para o depósito com 1 camada e basicamente ferrita e perlita refinadas para o deposito com 2 passes devido às baixas taxas de resfriamento
Juan Felipe Correa-Mesa; Diego Fabricio Rodríguez-Camacho; Diana Alexandra Camargo-Rojas; Juan Carlos Correa Morales
2016-01-01
Introducción. En lucha se presentan eventos que pueden generar alteraciones físicas, como caídas, contactos en el suelo, levantamientos, arqueamientos, entre otros. Objetivo. Estimar la prevalencia de lesiones y factores correlacionados en deportistas practicantes de lucha olímpica. Materiales y métodos. Estudio observacional de tipo correlacional y diseño transversal. Participaron 29 deportistas pertenecientes a la Liga de Bogotá. Resultados. En el último año, 15 deportistas no t...
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Norma Breda dos Santos
2003-12-01
Full Text Available O principal objetivo do presente estudo é o de demonstrar que a historiografia brasileira tem magnificado a responsabilidade brasileira nos acontecimentos de março de 1926 na Liga das Nações e que se concentra demasiadamente nas motivações do governo de Artur Bernardes, sem considerar aspectos decisivos concernentes à política internacional, notadamente a européia, e questões de ordem institucional próprias da Liga. Portanto, parece mais do que importante inserir internacionalmente a diplomacia de Bernardes, ou seja, pensá-la no contexto do fiasco da própria diplomacia internacional, dos "vinte anos de crise".The main objective of the present study is to demonstrate that the Brazilian historiography has magnified the Brazilian responsibility in the events of March 1926, in the League of Nations. It overconcentrates on the motivations of the government of Artur Bernardes, without considering decisive aspects related to the international politics, specially the European international politics, and institutional issues of the League itself. Thus, it seems more important to look the Brazilian diplomacy from an international perspective, that is, to think about it in the context of the "fiasco" of international diplomacy itself, in the time of "the twenty years crisis".
Lerman, Dorothea C; Tetreault, Allison; Hovanetz, Alyson; Bellaci, Emily; Miller, Jonathan; Karp, Hilary; Mahmood, Angela; Strobel, Maggie; Mullen, Shelley; Keyl, Alice; Toupard, Alexis
2010-01-01
We evaluated the feasibility and utility of a laboratory model for examining observer accuracy within the framework of signal-detection theory (SDT). Sixty-one individuals collected data on aggression while viewing videotaped segments of simulated teacher-child interactions. The purpose of Experiment 1 was to determine if brief feedback and contingencies for scoring accurately would bias responding reliably. Experiment 2 focused on one variable (specificity of the operational definition) that we hypothesized might decrease the likelihood of bias. The effects of social consequences and information about expected behavior change were examined in Experiment 3. Results indicated that feedback and contingencies reliably biased responding and that the clarity of the definition only moderately affected this outcome.
Castro, Carlos
2017-01-01
The first oncology conference organised by e cancer and the Liga Colombiana contra el Cancer took place on 17-18 November 2016 in Bogota. It was a highly successful event owing to the number of participants, the quality of the speakers, and the academic programme. Around 48 professors from 8 different countries came and shared their knowledge and experience of cancer management. They also talked about the most recent developments noted or achieved in this area. The keynote speech from Dr Nubia Muñoz was of great interest which was related to the safety of a HPV vaccine and the implications of a mass vaccination programme in developing countries. Geriatric oncology and palliative care were also topics that sparked great interest during the event.
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Luciano Arruda RIBAS
2004-12-01
Full Text Available Seis sistemas enzimáticos (ACP,G6PDH, IDH, PGI, PGM e SKDH, codificandosete locos polimórficos (Acp-3, G6pdh-1, Idh-1,Pgi-2, Pgm-1, Pgm-2 e Skdh-1, foram investigadospara a herança e desequilíbrio de ligação emCecropia pachystachya Trec. A herança mendelianafoi confirmada para todos os locos avaliados.Desvios significativos da razão de segregaçãoesperada 1:1 foram detectados apenas em umaprogênies de árvore heterozigótica. O desequilíbriode ligação foi examinado para 21 pares de locosisoenzimáticos, não sendo detectados desequilíbriosentre nenhum deles e, assim, estes podem serutilizados em subseqüentes estudos do sistemade reprodução, diversidade e estrutura genética deC. pachystachya.
An Information Theory Account of Preference Prediction Accuracy
Pollmann, Monique; Scheibehenne, Benjamin
2015-01-01
Knowledge about other people's preferences is essential for successful social interactions, but what exactly are the driving factors that determine how well we can predict the likes and dislikes of people around us? To investigate the accuracy of couples’ preference predictions we outline and
Kim, Sooyeon; Livingston, Samuel A.
2017-01-01
The purpose of this simulation study was to assess the accuracy of a classical test theory (CTT)-based procedure for estimating the alternate-forms reliability of scores on a multistage test (MST) having 3 stages. We generated item difficulty and discrimination parameters for 10 parallel, nonoverlapping forms of the complete 3-stage test and…
The accuracy of QCD perturbation theory at high energies
Dalla Brida, Mattia; Korzec, Tomasz; Ramos, Alberto; Sint, Stefan; Sommer, Rainer
2016-01-01
We discuss the determination of the strong coupling $\\alpha_\\mathrm{\\overline{MS}}^{}(m_\\mathrm{Z})$ or equivalently the QCD $\\Lambda$-parameter. Its determination requires the use of perturbation theory in $\\alpha_s(\\mu)$ in some scheme, $s$, and at some energy scale $\\mu$. The higher the scale $\\mu$ the more accurate perturbation theory becomes, owing to asymptotic freedom. As one step in our computation of the $\\Lambda$-parameter in three-flavor QCD, we perform lattice computations in a scheme which allows us to non-perturbatively reach very high energies, corresponding to $\\alpha_s = 0.1$ and below. We find that perturbation theory is very accurate there, yielding a three percent error in the $\\Lambda$-parameter, while data around $\\alpha_s \\approx 0.2$ is clearly insufficient to quote such a precision. It is important to realize that these findings are expected to be generic, as our scheme has advantageous properties regarding the applicability of perturbation theory.
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Adriana Paula Tirone
2005-06-01
Full Text Available OBJETIVO: Estudar os marcadores moleculares para os genes da cadeia pesada da beta-miosina cardíaca e da proteína-C de ligação à miosina em familiares de portadores de cardiomiopatia hipertrófica. MÉTODOS: Foram estudadas 12 famílias que realizaram anamnese, exame físico, eletrocardiograma, ecocardiograma e coleta de sangue para o estudo genético através da reação em cadeia da polimerasse. RESULTADOS: Dos 227 familiares 25% eram acometidos, sendo 51% do sexo masculino com idade média de 35±19 (2 a 95 anos. A análise genética mostrou ligação com o gene da b-miosina cardíaca em uma família e, em outra, ligação com o gene da proteína C de ligação à miosina. Em cinco famílias foram excluídas ligações com os dois genes; em duas, a ligação com o gene da proteína C de ligação à miosina, porém para o gene da b-miosina os resultados foram inconclusivos; em duas famílias os resultados foram inconclusivos para os dois genes e em uma foi excluída ligação para o gene da b-miosina mas ficou inconclusivo para o gene da proteína C de ligação à miosina. CONCLUSÃO: Em nosso meio, talvez predominem outros genes que não aqueles descritos na literatura, ou que existam outras diferenças genéticas relacionadas com a origem de nossa população e/ou fatores ambientais.OBJECTIVE: To study the molecular markers for the genes of the heavy chain of cardiac beta-myosin and the myosin binding protein C in relatives of carriers of hypertrophic cardiomyopathy. METHODS: Twelve families who had anamnesis, physical exam, electrocardiogram, echocardiogram and blood collection for the genetic study through the chain reaction of polymerase. RESULTS: From the 227 relatives, 25% were ill-taken, with 51% men, with an average age of 35±19 (2 to 95 years old. The genetic analysis showed a connection with the gene of the cardiac b-myosin in a family and, in another, a connection with the gene of the myosin-binding protein C. In five
A 90 años de la fundación de la Liga Feminista Costarricense: los derechos políticos
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Marta E. Solano Arias
2014-01-01
Full Text Available : Repaso de los derechos políticos de las mujeres con motivo del 90 aniversario de la fundación de la Liga Feminista Costarricense el 12 de octubre de 1923 en el Colegio Superior de Señoritas. El artículo ofrece un breve recorrido histórico de la participación de mujeres en hechos sociales y políticos relacionados con procesos electorales y la demanda del derecho el sufragio para las mujeres durante las primeras décadas del siglo XX y hasta 1925 en Costa Rica. Destaca algunas acciones de dos sufragistas descollantes durante los años 1912 a 1925, Ángela Acuña y Sara Casal.
Electrocautery versus Ultracision versus LigaSure in Surgical Management of Hyperhidrosis.
Divisi, Duilio; Di Leonardo, Gabriella; De Vico, Andrea; Crisci, Roberto
2015-12-01
The aim of the study was to evaluate the sympathectomy procedures for primary hyperhidrosis in terms of complications and effectiveness. From January 2010 to September 2012 we performed 130 sympathectomies in 65 patients, 27 males (42%) and 38 females (58%). Electrocoagulation was used in 20 procedures (15%), ultrasonic scalpel in 54 (42%), and radiofrequency dissector in 56 (43%). Seven patients (11%) underwent bilateral sympathectomy in the same surgical session, while in 58 (89%) the right surgical approach was delayed 30 days from the first procedure. We noticed 12 complications (9%): (a) chest pain in 6 patients (4 with electrocoagulation, 1 with ultrasonic scalpel, and 1 with radiofrequency dissector), which disappeared in 20 ± 1 day; (b) paresthesias in 3 electrocoagulation patients, was solved in 23 ± 5 days; (c) bradycardia in 1 ultrasonic patient, normalized in 4th postoperative hour; (d) unilateral relapse in 2 electrocoagulation patients after the second side approach, positively treated in 1 patient by resurgery in video-assisted thoracoscopy (VAT). The quality-adjusted life year and the quality of life evaluation revealed a statistically significant improvement (p = 0.02) in excessive sweating and general satisfaction after surgery, with Ultracision and LigaSure showing better findings than electrocoagulation. The latest generation devices offered greater efficacy in the treatment of hyperhidrosis, minimizing complications and facilitating the resumption of normal work and social activity of patients. Georg Thieme Verlag KG Stuttgart · New York.
Test expectancy affects metacomprehension accuracy.
Thiede, Keith W; Wiley, Jennifer; Griffin, Thomas D
2011-06-01
Theory suggests that the accuracy of metacognitive monitoring is affected by the cues used to judge learning. Researchers have improved monitoring accuracy by directing attention to more appropriate cues; however, this is the first study to more directly point students to more appropriate cues using instructions regarding tests and practice tests. The purpose of the present study was to examine whether the accuracy metacognitive monitoring was affected by the nature of the test expected. Students (N= 59) were randomly assigned to one of two test expectancy groups (memory vs. inference). Then after reading texts, judging learning, completed both memory and inference tests. Test performance and monitoring accuracy were superior when students received the kind of test they had been led to expect rather than the unexpected test. Tests influence students' perceptions of what constitutes learning. Our findings suggest that this could affect how students prepare for tests and how they monitoring their own learning. ©2010 The British Psychological Society.
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Müller-Stich Beat P
2011-06-01
Full Text Available Abstract Background The pp-Whipple procedure requires extensive preparation. The conventional preparation technique is done with scissors for dissection and ligatures, and with clips and sutures for hemostasis. This procedure is very time-consuming and requires numerous changes of instruments. The LigaSure™ device allows dissection and hemostasis for preparation with one instrument. Up to now there has been no comparison of the two techniques with regard to operating time and the patients' outcome. It is still unclear which technique has the optimal benefit/risk ratio for the patient. Methods/Design A single-center, randomized, single-blinded, controlled superiority trial to compare two different techniques for dissection in a pp-Whipple procedure. 102 patients will be included and randomized pre-operatively. All patients aged 18 years or older scheduled for primary elective pp-Whipple procedure who signed the informed consent will be included. The primary endpoint is the operating time of the randomized technique. Control Intervention: Conventional dissection technique; experimental intervention: LigaSureTM dissection technique. Duration of study: Approximately 15 months; follow up time: 3 years. The trial is registered at German ClinicalTrials Register (DRKS00000166.
La liga contra la ignorancia: burguesía y educación en la Valencia de 1880
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Luis M. LÁZARO LORENTE
2010-03-01
Full Text Available RESUMEN: «Instruid y moralizad al pueblo, y no temáis ni la explosión violenta de las pasiones populares ni el triunfo del despotismo; instruid y moralizad al pueblo, y no temáis poner en sus manos el hierro y el fuego, porque él os devolverá el primero convertido en útiles instrumentos del campo y del taller y en poderosas máquinas, y hará del segundo la fuerza que debe ponerlas en movimiento». Estos consejos de Cirilo Amorós cerraban el primer discurso de la noche. Era el día 22 de julio de 1880. En el pabellón municipal de la Feria de Julio, se estaba inaugurando de forma oficial la Liga contra la Ignorancia. La culminación de un proceso iniciado —ese mismo año— meses atrás.
Efeito do ácido fórmico na eletrodeposição de ligas Zn-Ni em substrato de aço
Pedroza, Graziella Aguiar Gomes
2013-01-01
A utilização dos depósitos de Zn-Ni eletrodepositados para melhorar a resistência à corrosão de chapas de aço revestidas tem atraído um interesse crescente porque oferece uma alternativa particularmente promissora para o Zn puro, devido às suas melhores propriedades mecânicas e de resistência à corrosão. Portanto, os estudos sobre os fatores que aumentam a eficiência de deposição e resistência à corrosão de eletrodepósitos das ligas Zn-Ni são altamente relevantes. Este trabalho descreve uma i...
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Rafael Yagüe BALLESTER
2001-12-01
Full Text Available As ligas de gálio surgiram como alternativa à problemática da toxicidade do mercúrio. Apresentam propriedades semelhantes às do amálgama, mas as pesquisas apontam duas características desfavoráveis: corrosão excessiva e grande magnitude de expansão de presa, podendo causar fraturas e rachaduras nas estruturas dentais. O objetivo foi avaliar in vitro a alteração dimensional durante 7 dias de uma liga de gálio (Galloy, SDI, Austrália, comparativamente com uma liga de amálgama contendo zinco (F-400, SDI, Austrália, em função do contato e/ou contaminação com solução salina (NaCl 0,9% nos estágios iniciais da cristalização. As condições experimentais de armazenagem foram em: ambiente seco; armazenagem em solução salina e contaminação com solução salina durante a condensação. Para o amálgama, foi ainda estudada a condição de contaminação introduzida na cápsula durante a trituração e para a liga de gálio, a proteção com resina fluida durante as primeiras 24 h ou durante todo o experimento. Os corpos-de-prova foram mantidos à temperatura de 37ºC ± 1ºC e suas dimensões monitoradas a cada 24 h, durante sete dias. O contato da liga de gálio com a solução salina durante a condensação ou nas primeiras horas após a condensação desencadeou uma expansão significantemente maior que as outras condições experimentais ao fim dos 7 dias. A aplicação de uma resina fluida para proteger a superfície dos cilindros foi capaz de evitar o aumento da expansão provocado pela umidade superficial. O amálgama não apresentou alterações significantes em nenhuma das condições experimentais, exceto quando contaminado durante a trituração.Gallium-based dental alloys were created with the aim of solving the problem of toxicity of mercury. The material shows mechanical properties similar to those of dental amalgam, but researches point out two unfavorable characteristics: great corrosion and excessive post
Evaluating measurement accuracy a practical approach
Rabinovich, Semyon G
2013-01-01
The goal of Evaluating Measurement Accuracy: A Practical Approach is to present methods for estimating the accuracy of measurements performed in industry, trade, and scientific research. From developing the theory of indirect measurements to proposing new methods of reduction, transformation, and enumeration, this work encompasses the full range of measurement data processing. It includes many examples that illustrate the application of general theory to typical problems encountered in measurement practice. As a result, the book serves as an inclusive reference work for data processing of all types of measurements: single and multiple, combined and simultaneous, direct (both linear and nonlinear), and indirect (both dependent and independent). It is a working tool for experimental scientists and engineers of all disciplines who work with instrumentation. It is also a good resource for natural science and engineering students and for technicians performing measurements in industry. A key feature of the book is...
Accuracy in Orbital Propagation: A Comparison of Predictive Software Models
2017-06-01
30] M. Lane and K. Cranford, "An improved analytical drag theory for the artificial satellite problem," American Institute of Aeronautics and...which have a foundation in similar theory . Since their first operational use, both propagators have incorporated updated theory and mathematical...propagators should therefore utilize the most current TLE data available to avoid accuracy errors. 14. SUBJECT TERMS orbital mechanics , orbital
Resistência de união entre liga de níquel-cromo e cimentos resinosos
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FRANÇA Rodrigo de Oliveira
1998-01-01
Full Text Available O objetivo do trabalho foi a determinação da retentividade, por ensaio de tração, entre uma liga de níquel-cromo e cimentos resinosos (Comspan, Panavia Ex e All-Bond C & B, com quatro tratamentos superficiais (liso, microjateado, ataque eletrolítico e silicoater e armazenagem por 3 e 30 dias em solução de NaCl a 0,9%, a 37° C e termociclagem intercalada na segunda (a 5 e 55° C, por 1 minuto em cada banho, perfazendo 600 ciclos. Os corpos de prova eram discos, providos de alça fixadora entre si dois a dois. Os resultados permitiram concluir que: superfícies lisas conduzem a baixíssimas retentividades e tratadas com silicoater a altíssimos valores, com qualquer cimento e condição de armazenagem; Panavia Ex com superfícies microjateadas também conduz a altas retentividades; a maior retentividade foi obtida pela combinação silicoater/All-Bond C&B.
Reis, J R
2000-01-01
Created in the early 1920s, at a moment when the country's psychiatric field was embracing the preventive outlook, the Liga Brasileira de Higiene Mental included within its members the elite of Brazilian psychiatry, along with a number of physicians and intellectuals. The article discusses the institution's proposals for intervention among children. The league ended up incorporating into its theoretical arsenal the basic themes of mental hygiene and eugenics as part of its general goal of collaborating in Brazil's process of "racial sanitation". With this objective in mind, and viewing the child as a "pre-citizen" who is a "fundamental part within the man of the future", league members included the children's issue in their projects and saw an imperative need for mental health care from early ages on.
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Claudia Fátima Silva HAITER
2002-03-01
Full Text Available O objetivo neste trabalho foi avaliar os efeitos da filtração alternativa da liga alumínio-zinco em aparelhos de raios X odontológicos, em relação ao espectro de energia dos feixes de raios X, a taxa de kerma no ar, o índice de contraste nas radiografias obtidas e a qualidade das imagens radiográficas. Este estudo foi realizado comparando-se o filtro convencional de alumínio com várias espessuras do filtro de liga alumínio-zinco, em diferentes porcentagens do elemento zinco na liga (2%, 3%, 4% e 5%. Foi utilizado um aparelho de raios X odontológico convencional, operando com 60 kVp e 70 kVp, e filmes radiográficos dos grupos D e E de sensibilidade. Foram realizadas radiografias de um "phantom" e de uma escala de densidade de alumínio. Os resultados mostraram que o uso dos filtros de liga Al-Zn resultou em um não-endurecimento dos feixes. A taxa de kerma no ar diminuiu em até 18,53%, sem alteração no contraste das radiografias e a qualidade das imagens teve uma boa aceitação pelos examinadores. A análise dos resultados nos levou a concluir que o filtro de liga Al-Zn 2%, com 1,99 mm de espessura, tensão de 60 kVp, quando usado com filme D, foi o que obteve melhor desempenho, reduzindo a taxa de kerma no ar sem variar o índice de contraste das radiografias, mantendo a qualidade da imagem aceitável para diagnóstico, sem contudo aumentar o tempo de exposição.The aim of this study was to evaluate the effects of alternative filtration with the aluminum-zinc alloy in dental X-ray devices, regarding the energy spectrum, dose, contrast and image quality. This study was carried out comparing the conventional aluminum filter with aluminum-zinc alloy filters of various thicknesses and with different percentages of zinc in the alloy (2, 3, 4 and 5%. A conventional X-ray device operating with 60 and 70 kVp as well as D- and E-speed films were utilized in order to obtain images of a phantom and an aluminum step wedge. The utilization
Julyana Ribeiro Garcia
2013-01-01
Revestimentos produzidos a partir de ligas de Zn-Co são comumente utilizados em indústrias (aeronáutica, de isoladores elétricos e automobilística, por exemplo) devido à sua ótima resistência à corrosão, principalmente quando comparados aos tradicionais revestimentos de Zn puro. Na co-deposição de zinco com metais, como o ferro, cobalto e níquel, ocorre o que se chama de deposição anômala, onde o metal menos nobre (zinco) é preferencialmente depositado, independente do modo de corrente aplica...
Study of Moessbauer effect on LiFe5-x Alx O8, LiFe 5-x Gax O8 and LiGa5-x Fex O8 systems
International Nuclear Information System (INIS)
Barthem, V.M.T.S.
1982-01-01
The measures obtained by Moessbauer spectroscopy from LiFe 5-x Ga x O 8 and LiFe 5-x Al x O 8 systems are presented. A comparative study of the influences of dopant diamagnetic ions on magnetic structures of lithium ferrite was performed. The LiGa 5-x Fe x O 8 systems were analysed based on the existing data from LiAl 5-x Fe x O 8 systems, otaining informations about the iron ion behaviour in both matrices. (M.C.K.) [pt
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J. Sánchez-Flores
2016-06-01
Conclusiones: La superioridad de los equipos más potentes parece clara, quizás excesiva, respecto al resto de equipos que participan en la principal liga española de fútbol. También se ha incrementado la probabilidad de que se consiga un número elevado de goles (> 5 goles en un partido. Esto provoca que la distribución del número de goles por partido sea del tipo binomial negativa.
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Iara de Moraes Xavier
2001-03-01
Full Text Available Este artigo tem como objetivo principal discutir as ligações perigosas entre as DSTs e o HIV/AIDS pelo prisma do gênero e da sexualidade. Apresenta a feminização da AIDS no Brasil como produto das relações sociais, econômicas, políticas e culturais. Pesquisa descritiva exploratória de natureza qualitativa. Focaliza mulheres com HIV/AIDS que se contaminaram através de relações sexuais com parceiros fixos e únicos. Conclui que o cuidado de enfermagem, no contexto do processo saúde-doença, constitui-se em uma das principais oportunidades para a (o enfermeira (o trabalhar o diagnóstico precoce, o tratamento e a prevenção das DSTs e da AIDS.
International Nuclear Information System (INIS)
Ecker, G.
1996-06-01
After a general introduction to the structure of effective field theories, the main ingredients of chiral perturbation theory are reviewed. Applications include the light quark mass ratios and pion-pion scattering to two-loop accuracy. In the pion-nucleon system, the linear σ model is contrasted with chiral perturbation theory. The heavy-nucleon expansion is used to construct the effective pion-nucleon Lagrangian to third order in the low-energy expansion, with applications to nucleon Compton scattering. (author)
Improving Accuracy of Processing Through Active Control
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N. N. Barbashov
2016-01-01
Full Text Available An important task of modern mathematical statistics with its methods based on the theory of probability is a scientific estimate of measurement results. There are certain costs under control, and under ineffective control when a customer has got defective products these costs are significantly higher because of parts recall.When machining the parts, under the influence of errors a range scatter of part dimensions is offset towards the tolerance limit. To improve a processing accuracy and avoid defective products involves reducing components of error in machining, i.e. to improve the accuracy of machine and tool, tool life, rigidity of the system, accuracy of the adjustment. In a given time it is also necessary to adapt machine.To improve an accuracy and a machining rate there, currently become extensively popular various the in-process gaging devices and controlled machining that uses adaptive control systems for the process monitoring. Improving the accuracy in this case is compensation of a majority of technological errors. The in-cycle measuring sensors (sensors of active control allow processing accuracy improvement by one or two quality and provide a capability for simultaneous operation of several machines.Efficient use of in-cycle measuring sensors requires development of methods to control the accuracy through providing the appropriate adjustments. Methods based on the moving average, appear to be the most promising for accuracy control since they include data on the change in some last measured values of the parameter under control.
A test theory of special relativity
International Nuclear Information System (INIS)
Mansouri, R.; Sexl, R.U.
1977-01-01
Various second-order optical tests of special relativity are discussed within the framework of a test theory developed previously. Owing to the low accuracy of the Kennedy-Thorndike experiment, the Lorentz contraction is known by direct experiments only to an accuracy of a few percent. To improve this accuracy several experiments are suggested. (author)
Coordinate metrology accuracy of systems and measurements
Sładek, Jerzy A
2016-01-01
This book focuses on effective methods for assessing the accuracy of both coordinate measuring systems and coordinate measurements. It mainly reports on original research work conducted by Sladek’s team at Cracow University of Technology’s Laboratory of Coordinate Metrology. The book describes the implementation of different methods, including artificial neural networks, the Matrix Method, the Monte Carlo method and the virtual CMM (Coordinate Measuring Machine), and demonstrates how these methods can be effectively used in practice to gauge the accuracy of coordinate measurements. Moreover, the book includes an introduction to the theory of measurement uncertainty and to key techniques for assessing measurement accuracy. All methods and tools are presented in detail, using suitable mathematical formulations and illustrated with numerous examples. The book fills an important gap in the literature, providing readers with an advanced text on a topic that has been rapidly developing in recent years. The book...
THE ACCURACY OF SCHEFFE'S THIRD DEGREE OVER SECOND ...
African Journals Online (AJOL)
NIJOTECH
Scheffe's (1958), simplex theory to optimize the compressive strength of concrete made from RHA pozzolan based on (4,2) and (4,3) simplex lattices. The strengths predicted by the models are in good agreement with their corresponding experimentally observed values. The accuracy of strength predicted by the third degree ...
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Alexandre Magno SEBBENN
2004-06-01
Full Text Available A herança e a ligação foram estudadasem quatro locos polimórficos (6pghd-1, Pgi-2,Mdh-1 e Mdh-2 de três sistemas isoenzimáticos deGenipa americana, analisados por eletroforesehorizontal em gel de amido, usando tecidoscoletados de quinze progênies de polinização aberta,procedentes de Moji-Guaçu, Estado de São Paulo.Esses locos segregaram de dois a três alelos.A segregação nesses locos foi homogênea entreárvores. Contudo, existem desvios significativos dasegregação esperada 1:1 para algumas árvores emalguns locos. Desvios significativos da razão desegregação esperada 1:1 foram detectados noslocos Mdh-2 e 6pgdh-1. Não foram detectadasevidências de ligação entre nenhum dos pares delocos avaliados em G. americana e esses podemser utilizados sem restrição para estudos do sistemade reprodução, diversidade e estrutura genética depopulações da espécie.Inheritance and linkage for fourpolymorphic loci (6pghd-1, Pgi-2, Mdh-1 andMdh-2 from three enzyme systems in Genipaamericana were analyzed by horizontal starch gelelectrophoresis using tissues collected from fiftyopen-pollinated families in Moji-Guaçu, São PauloState. These allozyme loci have segregated fromtwo to four alleles per polymorphic locus. Genesegregation on those loci was homogeneous amongtrees. However, there were significant deviationsfrom the expected segregation ratios on some lociand some individual trees. In addition, Mdh-2 and6pgdh-1 loci have shown significant deviationsfrom the 1:1 expected segregation ratio. Linkagedisequilibrium evidences were not detected betweenany two pairs of loci from G. americana and thosecan be used with no restriction to study the matingsystem, genetic diversity, and genetic structure onthe species.
Energy Technology Data Exchange (ETDEWEB)
Lara-Castells, María Pilar de, E-mail: Pilar.deLara.Castells@csic.es; Bartolomei, Massimiliano [Instituto de Física Fundamental (C.S.I.C.), Serrano 123, E-28006 Madrid (Spain); Mitrushchenkov, Alexander O. [Laboratoire Modélisation et Simulation Multi Echelle, Université Paris-Est, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée (France); Stoll, Hermann [Institut für Theoretische Chemie, Universität Stuttgart, D-70550 Stuttgart (Germany)
2015-11-21
The accuracy and transferability of the electronic structure approach combining dispersionless density functional theory (DFT) [K. Pernal et al., Phys. Rev. Lett. 103, 263201 (2009)] with the method of increments [H. Stoll, J. Chem. Phys. 97, 8449 (1992)], are validated for the interaction between the noble-gas Ne, Ar, Kr, and Xe atoms and coronene/graphene/graphite surfaces. This approach uses the method of increments for surface cluster models to extract intermonomer dispersion-like (2- and 3-body) correlation terms at coupled cluster singles and doubles and perturbative triples level, while periodic dispersionless density functionals calculations are performed to estimate the sum of Hartree-Fock and intramonomer correlation contributions. Dispersion energy contributions are also obtained using DFT-based symmetry-adapted perturbation theory [SAPT(DFT)]. An analysis of the structure of the X/surface (X = Ne, Ar, Kr, and Xe) interaction energies shows the excellent transferability properties of the leading intermonomer correlation contributions across the sequence of noble-gas atoms, which are also discussed using the Drude oscillator model. We further compare these results with van der Waals-(vdW)-corrected DFT-based approaches. As a test of accuracy, the energies of the low-lying nuclear bound states supported by the laterally averaged X/graphite potentials (X = {sup 3}He, {sup 4}He, Ne, Ar, Kr, and Xe) are calculated and compared with the best estimations from experimental measurements and an atom-bond potential model using the ab initio-assisted fine-tuning of semiempirical parameters. The bound-state energies determined differ by less than 6–7 meV (6%) from the atom-bond potential model. The crucial importance of including incremental 3-body dispersion-type terms is clearly demonstrated, showing that the SAPT(DFT) approach effectively account for these terms. With the deviations from the best experimental-based estimations smaller than 2.3 meV (1.9%), the
Image Positioning Accuracy Analysis for Super Low Altitude Remote Sensing Satellites
Directory of Open Access Journals (Sweden)
Ming Xu
2012-10-01
Full Text Available Super low altitude remote sensing satellites maintain lower flight altitudes by means of ion propulsion in order to improve image resolution and positioning accuracy. The use of engineering data in design for achieving image positioning accuracy is discussed in this paper based on the principles of the photogrammetry theory. The exact line-of-sight rebuilding of each detection element and this direction precisely intersecting with the Earth's elliptical when the camera on the satellite is imaging are both ensured by the combined design of key parameters. These parameters include: orbit determination accuracy, attitude determination accuracy, camera exposure time, accurately synchronizing the reception of ephemeris with attitude data, geometric calibration and precise orbit verification. Precise simulation calculations show that image positioning accuracy of super low altitude remote sensing satellites is not obviously improved. The attitude determination error of a satellite still restricts its positioning accuracy.
Dualities in M-theory and Born-Infeld Theory
International Nuclear Information System (INIS)
Brace, Daniel M.
2001-01-01
We discuss two examples of duality. The first arises in the context of toroidal compactification of the discrete light cone quantization of M-theory. In the presence of nontrivial moduli coming from the M-theory three form, it has been conjectured that the system is described by supersymmetric Yang-Mills gauge theory on a noncommutative torus. We are able to provide evidence for this conjecture, by showing that the dualities of this M-theory compactification, which correspond to T-duality in Type IIA string theory, are also dualities of the noncommutative supersymmetric Yang-Mills description. One can also consider this as evidence for the accuracy of the Matrix Theory description of M-theory in this background. The second type of duality is the self-duality of theories with U(1) gauge fields. After discussing the general theory of duality invariance for theories with complex gauge fields, we are able to find a generalization of the well known U(1) Born-Infeld theory that contains any number of gauge fields and which is invariant under the maximal duality group. We then find a supersymmetric extension of our results, and also show that our results can be extended to find Born-Infeld type actions in any even dimensional spacetime
Zhang, Bo
2010-01-01
This article investigates how measurement models and statistical procedures can be applied to estimate the accuracy of proficiency classification in language testing. The paper starts with a concise introduction of four measurement models: the classical test theory (CTT) model, the dichotomous item response theory (IRT) model, the testlet response…
International Nuclear Information System (INIS)
Geroyannis, V.S.
1988-01-01
In this paper, a numerical method is developed for determining the structure distortion of a polytropic star which rotates either uniformly or differentially. This method carries out the required numerical integrations in the complex plane. The method is implemented to compute indicative quantities, such as the critical perturbation parameter which represents an upper limit in the rotational behavior of the star. From such indicative results, it is inferred that this method achieves impressive improvement against other relevant methods; most important, it is comparable to some of the most elaborate and accurate techniques on the subject. It is also shown that the use of this method with Chandrasekhar's first-order perturbation theory yields an immediate drastic improvement of the results. Thus, there is no neeed - for most applications concerning rotating polytropic models - to proceed to the further use of the method with higher order techniques, unless the maximum accuracy of the method is required. 31 references
Directory of Open Access Journals (Sweden)
Antonio Rodolfo Paulino Pessoa
2011-03-01
Full Text Available Neste trabalho foram calculados e comparados os custos de soldagem associados a cada um dos ensaios realizados, como forma de determinar parâmetros operacionais adequados e economicamente viáveis para soldagem com o processo MIG/MAG com transferência metálica por curto-circuito, visando uma correta deposição de revestimentos com ligas de níquel sobre um substrato de aço C-Mn. O número de ensaios a serem realizados, foi determinado pelo uso do método Taguchi que dividiu os ensaios em duas matrizes L9, resultando num total de 18 ensaios. Na comparação dos gastos despendidos em cada um dos ensaios foi utilizado o custo direto total da soldagem de um revestimento com 55 mm de largura e 190 mm de comprimento, utilizando uma sobreposição de 50%. Com base nos resultados dos ensaios foram pré-selecionados quatro ensaios (R7, R11, R12 e RC4, dentre os quais o ensaio R11 apresentou o menor custo. Mas vale ressaltar que nos quatro ensaios pré-selecionados o material de adição utilizado foi a liga 625, pois esta liga apresentar um custo do arame-eletrodo muito inferior as demais ligas (C-276 e 686. Assim a escolha do material de adição para aplicação do revestimento ficou restrita somente a liga 625.In this work were calculated and compared the welding costs for each of the tests performed to determine operational parameters and economically feasible for welding with GMAW process in a short circuiting transfer mode, aiming at a correct weld overlay with nickel alloy on a substrate of C-Mn steel. The number of tests to be performed was determined by using the Taguchi method that divided the tests into two L9 orthogonal arrays resulting in a total of 18 experiments. To compare the costs incurred in each of the tests we used the total direct cost of welding a layer with dimensions of 55 x 190 mm, using an overlap of 50%. Based on the results of the tests were pre-selected four tests (R7, R11, R12 and RC4, among which the test R11 has the
Perturbation theory and importance functions in integral transport formulations
International Nuclear Information System (INIS)
Greenspan, E.
1976-01-01
Perturbation theory expressions for the static reactivity derived from the flux, collision density, birth-rate density, and fission-neutron density formulations of integral transport theory, and from the integro-differential formulation, are intercompared. The physical meaning and relation of the adjoint functions corresponding to each of the five formulations are established. It is found that the first-order approximation of the perturbation expressions depends on the transport theory formulation and on the adjoint function used. The approximations of the integro-differential formulation corresponding to different first-order approximations of the integral transport theory formulations are identified. It is found that the accuracy of all first-order approximations of the integral transport formulations examined is superior to the accuracy of first-order integro-differential perturbation theory
A theory of cross-validation error
Turney, Peter D.
1994-01-01
This paper presents a theory of error in cross-validation testing of algorithms for predicting real-valued attributes. The theory justifies the claim that predicting real-valued attributes requires balancing the conflicting demands of simplicity and accuracy. Furthermore, the theory indicates precisely how these conflicting demands must be balanced, in order to minimize cross-validation error. A general theory is presented, then it is developed in detail for linear regression and instance-bas...
Barreno Paredes, Ana María; Zaruma Silva, Juan José; Viinueza Guerrero, Franklin Roberto
2012-01-01
Al ser el fútbol, el deporte más practicado y seguido a nivel mundial, se convierte en un fenómeno social y cultural, que atrae a millones de personas a sus escenarios deportivos cada semana. El Ecuador se encuentra inmerso en la fiebre del fútbol, siendo Quito el espacio donde se expresan estas pasiones. Aucas y Liga, dos clubes de enorme valía histórica, cultural, social y deportiva han abierto sus puertas, dando la oportunidad de estudiar a fondo sus hichadas, sus instituciones y todo alre...
Modeling Linkage Disequilibrium Increases Accuracy of Polygenic Risk Scores
DEFF Research Database (Denmark)
Vilhjálmsson, Bjarni J; Yang, Jian; Finucane, Hilary K
2015-01-01
to association statistics, but this discards information and can reduce predictive accuracy. We introduce LDpred, a method that infers the posterior mean effect size of each marker by using a prior on effect sizes and LD information from an external reference panel. Theory and simulations show that LDpred...
d'plus: A program to calculate accuracy and bias measures from detection and discrimination data.
Macmillan, N A; Creelman, C D
1997-01-01
The program d'plus calculates accuracy (sensitivity) and response-bias parameters using Signal Detection Theory. Choice Theory, and 'nonparametric' models. is is appropriate for data from one-interval, two- and three-interval forced-choice, same different, ABX, and oddity experimental paradigms.
Test theory of special relativity: What it is and why we need it
International Nuclear Information System (INIS)
Mansouri, R.
1988-03-01
After a critical overview on the traditional way of expressing the accuracy of experiments testing the postulates of the special theory of relativity, the four-parameter test theory is briefly introduced. The existing experiments are then classified and their accuracies are expressed in terms of the parameter of the test theory. By changing the convention of synchronization of distant clocks, it is shown how different equivalent theories can be formulated. (author). 23 refs
International Nuclear Information System (INIS)
Hayward, Robert M.; Rahnema, Farzad; Zhang, Dingkang
2013-01-01
Highlights: ► A new hybrid stochastic–deterministic transport theory method to couple with diffusion theory. ► The method is implemented in 2D hexagonal geometry. ► The new method produces excellent results when compared with Monte Carlo reference solutions. ► The method is fast, solving all test cases in less than 12 s. - Abstract: A new hybrid stochastic–deterministic transport theory method, which is designed to couple with diffusion theory, is presented. The new method is an extension of the incident flux response expansion method, and it combines the speed of diffusion theory with the accuracy of transport theory. With ease of use in mind, the new method is derived in such a way that it can be implemented with only minimal modifications to an existing diffusion theory method. A new angular expansion, which is necessary for the diffusion theory coupling, is developed in 2D and 3D. The method is implemented in 2D hexagonal geometry, and an HTTR benchmark problem is used to test its accuracy in a standalone configuration. It is found that the new method produces excellent results (with average relative error in partial current less than 0.033%) when compared with Monte Carlo reference solutions. Furthermore, the method is fast, solving all test cases in less than 12 s
Kinematical Test Theories for Special Relativity
Lämmerzahl, Claus; Braxmaier, Claus; Dittus, Hansjörg; Müller, Holger; Peters, Achim; Schiller, Stephan
A comparison of certain kinematical test theories for Special Relativity including the Robertson and Mansouri-Sext test theories is presented and the accuracy of the experimental results testing Special Relativity are expressed in terms of the parameters appearing in these test theories. The theoretical results are applied to the most precise experimental results obtained recently for the isotropy of light propagation and the constancy of the speed of light.
Cavalcante, Nathália Escóssio; Andrade, Tathiane Caminha; Pinheiro, Pedro Helton Magalhães; Miranda, Hélio Cordeiro de; Motta, Marcelo Ferreira; Aguiar, Willys Machado
2016-01-01
Resumo O presente trabalho objetiva o estudo de técnicas de soldagem aplicadas a reparo de componentes fabricados em aço ASTM A387 Gr.11, largamente utilizado em aplicações da indústria do petróleo e gás. Devido ao regime de trabalho e necessidade de utilização de materiais com boa resistência mecânica e à corrosão, utilizou-se como metal de adição a liga UNS N06625 (Inconel 625). O processo de soldagem utilizado foi o MIG/MAG e a técnica de soldagem aplicada foi a dupla camada. A metodologia...
Recollection is a continuous process: implications for dual-process theories of recognition memory.
Mickes, Laura; Wais, Peter E; Wixted, John T
2009-04-01
Dual-process theory, which holds that recognition decisions can be based on recollection or familiarity, has long seemed incompatible with signal detection theory, which holds that recognition decisions are based on a singular, continuous memory-strength variable. Formal dual-process models typically regard familiarity as a continuous process (i.e., familiarity comes in degrees), but they construe recollection as a categorical process (i.e., recollection either occurs or does not occur). A continuous process is characterized by a graded relationship between confidence and accuracy, whereas a categorical process is characterized by a binary relationship such that high confidence is associated with high accuracy but all lower degrees of confidence are associated with chance accuracy. Using a source-memory procedure, we found that the relationship between confidence and source-recollection accuracy was graded. Because recollection, like familiarity, is a continuous process, dual-process theory is more compatible with signal detection theory than previously thought.
Experimental status of unified theories
International Nuclear Information System (INIS)
Bilen'kij, S.M.
1979-01-01
A standard SU(2)xU(1) theory is discussed. It is based on an assumption that the left components of fields form doublets, and the rignt ones - singlets. From the weak interaction lagrangian an expression is obtained for the effective hamiltonian describing neutrino-lepton processes. The results of discussing the experimental status of the unified theories of weak and electromagnetic interactions are in agreement with the simplest version of the unified theories - the Weinberg-Salam theory. It has been noted that the accuracy of the experiments (not exceeding 20%) is insufficient and no information is available on diagonal terms of the hamiltonian
Relevance of intracellular polarity to accuracy of eukaryotic chemotaxis
International Nuclear Information System (INIS)
Hiraiwa, Tetsuya; Nishikawa, Masatoshi; Shibata, Tatsuo; Nagamatsu, Akihiro; Akuzawa, Naohiro
2014-01-01
Eukaryotic chemotaxis is usually mediated by intracellular signals that tend to localize at the front or back of the cell. Such intracellular polarities frequently require no extracellular guidance cues, indicating that spontaneous polarization occurs in the signal network. Spontaneous polarization activity is considered relevant to the persistent motions in random cell migrations and chemotaxis. In this study, we propose a theoretical model that connects spontaneous intracellular polarity and motile ability in a chemoattractant solution. We demonstrate that the intracellular polarity can enhance the accuracy of chemotaxis. Chemotactic accuracy should also depend on chemoattractant concentration through the concentration-dependent correlation time in the polarity direction. Both the polarity correlation time and the chemotactic accuracy depend on the degree of responsiveness to the chemical gradient. We show that optimally accurate chemotaxis occurs at an intermediate responsiveness of intracellular polarity. Experimentally, we find that the persistence time of randomly migrating Dictyostelium cells depends on the chemoattractant concentration, as predicted by our theory. At the optimum responsiveness, this ameboid cell can enhance its chemotactic accuracy tenfold. (paper)
Directory of Open Access Journals (Sweden)
Karim Alvis
2013-04-01
Full Text Available Antecedentes. El Boccia es un deporte que debido a suscaracterísticas técnicas y metodológicas ya que es mixto, deprecisión y estrategia, permite la participación de individuoscon diversos tipos de limitaciones físicas, permitiendo de estaforma la integración social de los mismos, en un contexto deequidad, por lo cual ha tenido una gran acogida a nivel mundialsiendo catalogado como el deporte bandera de la AsociaciónInternacional de Deportes y Recreación para personas conParálisis Cerebral (CP-ISRA.Objetivo. Explorar los posibles significados que para mujeresy hombres en situación de discapacidad, tiene la práctica delBoccia como factor de integración social.Materiales y métodos. Esta investigación optó por el enfoqueCualitativo etnográfico, a través de las narrativas y experienciasde los protagonistas en este caso mujeres y hombres quehacen parte de la liga de Parálisis Cerebral de Bogotá- Boccia.Para estos efectos se utilizaron instrumentos como las entrevistassemiestructuradas, grupos focales y narrativas visuales.Resultados. El documento presenta un análisis de la percepcióny los alcances de la práctica de un deporte como el Bocciaen la integración social de los individuos desde las categoríasde los conceptos de solidaridad, autonomía, reconocimientode la diversidad, participación, universalidad, equidad, corresponsabilidad,efectividad, poder, libertad e identidad.Conclusión. Se concluye que los significados otorgados alBoccia como factor de integración social, por parte de losparticipantes en la Liga, en general se enmarcan de manerapositiva en las categorías conceptuales propuestas para suanálisis. Sin embargo, existe aún un alto desconocimiento de ladiscapacidad y de aceptación de las diferencias que se convierteen un factor limitante para una adecuada integración social.
The influence of delaying judgments of learning on metacognitive accuracy: a meta-analytic review.
Rhodes, Matthew G; Tauber, Sarah K
2011-01-01
Many studies have examined the accuracy of predictions of future memory performance solicited through judgments of learning (JOLs). Among the most robust findings in this literature is that delaying predictions serves to substantially increase the relative accuracy of JOLs compared with soliciting JOLs immediately after study, a finding termed the delayed JOL effect. The meta-analyses reported in the current study examined the predominant theoretical accounts as well as potential moderators of the delayed JOL effect. The first meta-analysis examined the relative accuracy of delayed compared with immediate JOLs across 4,554 participants (112 effect sizes) through gamma correlations between JOLs and memory accuracy. Those data showed that delaying JOLs leads to robust benefits to relative accuracy (g = 0.93). The second meta-analysis examined memory performance for delayed compared with immediate JOLs across 3,807 participants (98 effect sizes). Those data showed that delayed JOLs result in a modest but reliable benefit for memory performance relative to immediate JOLs (g = 0.08). Findings from these meta-analyses are well accommodated by theories suggesting that delayed JOL accuracy reflects access to more diagnostic information from long-term memory rather than being a by-product of a retrieval opportunity. However, these data also suggest that theories proposing that the delayed JOL effect results from a memorial benefit or the match between the cues available for JOLs and those available at test may also provide viable explanatory mechanisms necessary for a comprehensive account.
As origens da participação da América Latina na Organização de Saúde da Liga das Nações, 1920 a 1940
Weindling, Paul
2006-01-01
A Organização de Saúde da Liga das Nações colaborou com especialistas latino-americanos em saúde pública e doenças infecciosas desde o início da década de 1920 e até a eclosão da Segunda Guerra Mundial. Desenvolveu estudos sobre saúde e nutrição infantil e sobre a lepra. A abordagem foi orientada por especialistas, tendo em mira o desenvolvimento da saúde pública em bases científicas. Houve conferências, visitas e relatórios sobre a América Latina. O artigo demonstra que a colaboração da Amér...
Rosa, Marta; Micciarelli, Marco; Laio, Alessandro; Baroni, Stefano
2016-09-13
We introduce a method to evaluate the relative populations of different conformers of molecular species in solution, aiming at quantum mechanical accuracy, while keeping the computational cost at a nearly molecular-mechanics level. This goal is achieved by combining long classical molecular-dynamics simulations to sample the free-energy landscape of the system, advanced clustering techniques to identify the most relevant conformers, and thermodynamic perturbation theory to correct the resulting populations, using quantum-mechanical energies from density functional theory. A quantitative criterion for assessing the accuracy thus achieved is proposed. The resulting methodology is demonstrated in the specific case of cyanin (cyanidin-3-glucoside) in water solution.
The influence of affective empathy and autism spectrum traits on empathic accuracy
Aan Het Rot, Marije; Hogenelst, Koen
Autism spectrum disorder is characterized by interpersonal deficits and has been associated with limited cognitive empathy, which includes perspective taking, theory of mind, and empathic accuracy (EA). The capacity for affective empathy may also be impaired. In the present study we aimed to
The Theory of Variances in Equilibrium Reconstruction
International Nuclear Information System (INIS)
Zakharov, Leonid E.; Lewandowski, Jerome; Foley, Elizabeth L.; Levinton, Fred M.; Yuh, Howard Y.; Drozdov, Vladimir; McDonald, Darren
2008-01-01
The theory of variances of equilibrium reconstruction is presented. It complements existing practices with information regarding what kind of plasma profiles can be reconstructed, how accurately, and what remains beyond the abilities of diagnostic systems. The σ-curves, introduced by the present theory, give a quantitative assessment of quality of effectiveness of diagnostic systems in constraining equilibrium reconstructions. The theory also suggests a method for aligning the accuracy of measurements of different physical nature
Plan de Acción para la Educación Antidopaje de los Peloteros Pinareños de la Liga de Desarrollo
Directory of Open Access Journals (Sweden)
Raciel Lezcano Valdes
2009-12-01
Full Text Available Debido al creciente grado de competitividad y a la frecuencia de las competiciones de alto nivel, el dopaje se ha convertido en una de sus mayores lacras. Por ello, muchos organismos nacionales e internacionales han tomado medidas preventivas para evitarlo, como la elaboración de listas de productos prohibidos. Sin embargo, el contenido de éstas varía según los países, las federaciones y las instancias de cada deporte que las redactan. El Comité Olímpico Internacional (COI se ha encargado de establecer unas normativas generales y categorías de productos dopantes comunes. El uso de las sustancias prohibidas en el listado del Comité Olímpico Internacional dentro del béisbol es tan antiguo como en otras especialidades deportivas aunque con algunas especificidades. Inicialmente suscriptos a los grande círculos del béisbol profesional norteamericano, en la actualidad amenaza con generalizarse a otras ligas y categorías, principalmente en atletas juveniles y universitarios, que por medio de ellos intentan ingresar al gran espectáculo.
Subtraction method of computing QCD jet cross sections at NNLO accuracy
Trócsányi, Zoltán; Somogyi, Gábor
2008-10-01
We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in next-to-leading order computations. However, all steps need non-trivial modifications, which we implement such that that those can be defined at any order in perturbation theory. We give a status report of the implementation of the method to computing jet cross sections in electron-positron annihilation at the next-to-next-to-leading order accuracy.
Subtraction method of computing QCD jet cross sections at NNLO accuracy
Energy Technology Data Exchange (ETDEWEB)
Trocsanyi, Zoltan [University of Debrecen and Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen P.O.Box 51 (Hungary)], E-mail: Zoltan.Trocsanyi@cern.ch; Somogyi, Gabor [University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland)], E-mail: sgabi@physik.unizh.ch
2008-10-15
We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in next-to-leading order computations. However, all steps need non-trivial modifications, which we implement such that that those can be defined at any order in perturbation theory. We give a status report of the implementation of the method to computing jet cross sections in electron-positron annihilation at the next-to-next-to-leading order accuracy.
Directory of Open Access Journals (Sweden)
Emi Kitashoji
Full Text Available Leptospirosis is an important but largely under-recognized public health problem in the tropics. Establishment of highly sensitive and specific laboratory diagnosis is essential to reveal the magnitude of problem and to improve treatment. This study aimed to evaluate the diagnostic accuracy of a recombinant LigA protein based IgM ELISA during outbreaks in the clinical-setting of a highly endemic country.A prospective study was conducted from October 2011 to September 2013 at a national referral hospital for infectious diseases in Manila, Philippines. Patients who were hospitalized with clinically suspected leptospirosis were enrolled. Plasma and urine were collected on admission and/or at discharge and tested using the LigA-IgM ELISA and a whole cell-based IgM ELISA. Sensitivity and specificity of these tests were evaluated with cases diagnosed by microscopic agglutination test (MAT, culture and LAMP as the composite reference standard and blood bank donors as healthy controls: the mean+3 standard deviation optical density value of healthy controls was used as the cut-off limit (0.062 for the LigA-IgM ELISA and 0.691 for the whole cell-based IgM ELISA. Of 304 patients enrolled in the study, 270 (89.1% were male and the median age was 30.5 years; 167 (54.9% were laboratory confirmed. The sensitivity and ROC curve AUC for the LigA-IgM ELISA was significantly greater than the whole cell-based IgM ELISA (69.5% vs. 54.3%, p<0.01; 0.90 vs. 0.82, p<0.01 on admission, but not at discharge. The specificity of LigA-IgM ELISA and whole cell-based IgM ELISA were not significantly different (98% vs. 97%. Among 158 MAT negative patients, 53 and 28 were positive by LigA- and whole cell-based IgM ELISA, respectively; if the laboratory confirmation was re-defined by LigA-IgM ELISA and LAMP, the clinical findings were more characteristic of leptospirosis than the diagnosis based on MAT/culture/LAMP.The newly developed LigA-IgM ELISA is more sensitive than the
Graph-based linear scaling electronic structure theory
Energy Technology Data Exchange (ETDEWEB)
Niklasson, Anders M. N., E-mail: amn@lanl.gov; Negre, Christian F. A.; Cawkwell, Marc J.; Swart, Pieter J.; Germann, Timothy C.; Bock, Nicolas [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Mniszewski, Susan M.; Mohd-Yusof, Jamal; Wall, Michael E.; Djidjev, Hristo [Computer, Computational, and Statistical Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Rubensson, Emanuel H. [Division of Scientific Computing, Department of Information Technology, Uppsala University, Box 337, SE-751 05 Uppsala (Sweden)
2016-06-21
We show how graph theory can be combined with quantum theory to calculate the electronic structure of large complex systems. The graph formalism is general and applicable to a broad range of electronic structure methods and materials, including challenging systems such as biomolecules. The methodology combines well-controlled accuracy, low computational cost, and natural low-communication parallelism. This combination addresses substantial shortcomings of linear scaling electronic structure theory, in particular with respect to quantum-based molecular dynamics simulations.
Application of diffusion theory to the transport of neutral particles in fusion plasmas
International Nuclear Information System (INIS)
Hasan, M.Z.
1985-01-01
It is shown that the widely held view that diffusion theory can not provide good accuracy for the transport of neutral particles in fusion plasmas is misplaced. In fact, it is shown that multigroup diffusion theory gives quite good accuracy as compared to the transport theory. The reasons for this are elaborated and some of the physical and theoretical reasons which make the multigroup diffusion theory provide good accuracy are explained. Energy dependence must be taken into consideration to obtain a realistic neutral atom distribution in fusion plasmas. There are two reasons for this; presence of either is enough to necessitate an energy dependent treatment. First, the plasma temperature varies spatially, and second, the ratio of charge-exchange to total plasma-neutral interaction cross section (c) is not close to one. A computer code to solve the one-dimensional multigroup diffusion theory in general geometry (slab, cylindrical and spherical) has been written for use on Cray computers, and its results are compared with those from the one-dimensional transport code ANISN to support the above finding. A fast, compact and versatile two-dimensional finite element multigroup diffusion theory code, FINAT, in X-Y and R-Z cylindrical/toroidal geometries has been written for use on CRAY computers. This code has been compared with the two dimensional transport code DOT-4.3. The accuracy is very good, and FENAT runs much faster compared even to DOT-4.3 which is a finite difference code
Directory of Open Access Journals (Sweden)
Milena Luckesi de Souza
2008-08-01
Full Text Available O objetivo deste texto é investigar a concepção e as propostas de atendimento escolar destinado aos deficientes mentais segundo o ideário higienista e eugenista difundido pela Liga Brasileira de Higiene Mental (LBHM. Para tanto, utilizamos como fonte primária de estudo os Arquivos Brasileiros de Higiene Mental (ABHM, periódico publicado entre 1925 e 1947. Verificamos que a LBHM expressa diferentes opiniões quanto à concepção e às medidas de intervenção propostas para os deficientes mentais. De um lado, propõe a higienização da população, a ser alcançada com a formação de hábitos sadios através da educação escolar e especificamente da educação higiênica, com a possível adaptação do deficiente ao meio social. De outro, defende uma posição eugênica radical, que apregoa a purificação da raça, a esterilização e exclusão dos ditos degenerados (leprosos, loucos, idiotas, epilépticos, cancerosos, nefrolíticos, tuberculosos, prostitutas, vagabundos e deficientes mentais.The aim of this study is to investigate the conception and proposals of schooling for individuals with mental disability according to the hygienic and eugenic ideology divulged by the Brazilian League for Mental Hygiene (Liga Brasileira de Higiene Mental, LBHM. To this end, we used as a primary source the Brazilian Archives of Mental Hygiene (Arquivos Brasileiros de Higiene Mental, ABHM, a newspaper published from 1925 to 1947. We concluded that there were various opinions in the LBHM about the conception and proposed intervention methods for individuals with mental disability. On one side, there were proposals of population cleansing to be achieved through healthy habits taught in schools, mainly hygienic education, with possible adaptation of the disabled individual to society. On the other hand, there was an extreme eugenic proposal that emphasized race purification, sterilization and exclusion of so-called degenerate individuals (lepers
Directory of Open Access Journals (Sweden)
Jussara Calmon Reis de Souza Soares
2012-01-01
Full Text Available O presente trabalho busca trazer novos elementos para o debate sobre a judicialização da saúde e sobre o acesso a medicamentos. Parte-se de um breve panorama do setor farmacêutico, seguido de um levantamento bibliográfico sobre demandas judiciais por medicamentos no Brasil, para fundamentar uma reflexão sobre as ligações entre a indústria farmacêutica e as associações de pacientes, que podem estar interferindo no processo. Tais ligações resultam das novas estratégias de expansão do mercado pelo setor farmacêutico, e podem agravar o panorama da saúde brasileira em relação ao uso crítico e responsável dos medicamentos. A necessidade de desmercantilização da saúde é incluída nesse debate.The main objective of this paper is to contribute to the debate on the legal claims for pharmaceutical drugs in Brazil, as part of the struggle for access to these products. A brief discussion about the pharma industry is made, followed by the state-of-the-art of the so-called process of "health judicialization". These are the basis for the reflections on the relationships between the corporations and patients' associations, which are part of the strategies used by the pharma industry in order to expand the market. These liaisons may be influencing the augmentation of court requests, thus damaging the responsible drug use. The role of commodification of healthcare is discussed.
X-ray bursts: Observation versus theory
Lewin, W. H. G.
1981-01-01
Results of various observations of common type I X-ray bursts are discussed with respect to the theory of thermonuclear flashes in the surface layers of accreting neutron stars. Topics covered include burst profiles; irregular burst intervals; rise and decay times and the role of hydrogen; the accuracy of source distances; accuracy in radii determination; radius increase early in the burst; the super Eddington limit; temperatures at burst maximum; and the role of the magnetic field.
Convergent perturbation expansions for Euclidean quantum field theory
International Nuclear Information System (INIS)
Mack, G.; Pordt, A.
1984-09-01
Mayer perturbation theory is designed to provide computable convergent expansions which permit calculation of Greens functions in Euclidean Quantum Field Theory to arbitrary accuracy, including 'nonperturbative' contributions from large field fluctuations. Here we describe the expansions at the example of 3-dimensional lambdaphi 4 -theory (in continuous space). They are not essentially more complicated than standard perturbation theory. The n-th order term is expressed in terms of 0(n)-dimensional integrals, and is of order lambda 4 if 4k-3<=n<=4k. (orig.)
Avaliação da Capacidade de Decisão em Psiquiatria de Ligação
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Filipe Lopes Vicente
2017-03-01
Full Text Available Introdução: Entre as funções do psiquiatra de ligação, encontra-se a avaliação da capacidade de decidir. Esta envolve a capacidade de fazer escolhas de forma autónoma e surge de forma relevante na prática clínica diária como pré-condição ao consentimento informado. Objetivos: Os autores pretendem rever o pro- cesso subjacente à avaliação da capacidade de decisão, assim como outra informação relevante publicada a este respeito. Métodos: Revisão não sistemática da literatura através da pesquisa eletrónica nos motores de busca Medline/Pubmed. Resultados: A capacidade de decidir apenas pode ser avaliada relativamente a uma decisão em particular, sendo que o seu resultado não é necessariamente estável ao longo do tempo. Da mesma forma, não existe nenhum diagnóstico que permita concluir, por si só, pela incapacidade para decidir ou que possibilite prescindir da sua avaliação. Depende de vários fatores: conteúdo, forma do pensa- mento e funções cognitivas. Pode igualmente ser influenciada pelo nível de instrução do indivíduo, traços da personalidade, estados emocionais/mecanismos de coping ou fatores circunstanciais. Qualquer médico deverá estar habilitado para a realização desta avaliação. O psiquiatra de ligação deve ser envolvido perante a suspeita de doença mental capaz de prejudicar a capacidade de consentir ou perante a necessidade de validar uma avaliação já realizada. Appelbaum e Grisso propuseram uma avaliação sistematizada segundo os seguintes critérios: a comunicação da escolha, b compreensão, c apreciação e d processo de decisão racional/ raciocínio. Numa tentativa de minimizar diferenças entre avaliadores, foram desenvolvidos vários instrumentos de avaliação, entre os quais se destaca a MacArthur Competence Assessment Tool. Particularmente nos doentes com d
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Vinícius Toledo Saccon
2010-12-01
Full Text Available Este trabalho visou analisar a caracterização microestrutural e o comportamento mecânico das ligas de alumínio AA2139 T3 e T8 quando são soldadas pelo processo Soldagem por Fricção Rotativa com Mistura, o qual é realizado na fase sólida. A análise microestrutural foi realizada utilizando microscopia óptica e eletrônica de varredura, e o comportamento mecânico foi avaliado através de medidas de microdureza e ensaio de tração convencional complementado pelo sistema ARAMIS. As ligas foram soldadas nos mesmos parâmetros de soldagem e com a mesma ferramenta, a fim de avaliar a qualidade da junta soldada para as duas condições de tratamento térmico, T3 e T8. Os resultados obtidos mostraram soldas resistentes para ambos os tratamentos térmicos, porém com melhores propriedades mecânicas para a liga AA2139 T3.This work aimed to study the microstructural characterization and mechanical behavior of AA2139 T3 and T8 aluminum alloys joined by FSW - Friction Stir Welding. The microstructural analysis has been done using optical microscope and scanning electron microscopy, and the mechanical analysis were evaluate through microhardness testing and conventional tensile test using the ARAMIS system . Each alloy were welded using the same welding parameters and the same tool in order to evaluate the joint quality for both heat treatment used for this work, T3 and T8. The result showed sounds joints for both heat treatments, although with better mechanical properties for the alloy AA2139 T3.
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Mariana Pretti
2004-12-01
Full Text Available INTRODUCTION: Based on the importance of the integrity of the metal/ceramic interface, the purpose of this work was to evaluate the shear bond strength of the metal-ceramic union of two Co-Cr alloys (Wirobond C, Bego; Remanium 2000, Dentaurum combined with Omega 900 ceramic (Vita Zahnfabrik. MATERIAL AND METHOD: Eleven cylindrical matrixes were made for each alloy, and the metallic portion was obtained with the lost wax casting technique with standardized waxing of 4mm of height and of 4mm of diameter. The ceramic was applied according to the manufacturer's recommendations with the aid of a teflon matrix that allowed its dimension to be standardized in the same size as the metallic portion. The specimens were submitted to the shear bond test in an universal testing machine (EMIC, with the aid of a device developed for such intention, and constant speed of 0.5mm/min. RESULTS AND CONCLUSIONS: The mean resistance was 48.387MPa for Wirobond C alloy, with standard deviation of 17.718, and 55.956MPa for Remanium 2000, with standard deviation of 17.198. No statistically significant difference was observed between the shear strength of the two metal-ceramic alloys.INTRODUÇÃO: Baseados na importância da integridade da interface metal-cerâmica, este trabalho tem como objetivo avaliar a resistência ao cisalhamento da união metal-cerâmica de duas ligas de Co-Cr (Wirobond C, Bego; Remanium 2000, Dentaurum combinadas com a cerâmica Omega 900 (Vita Zahnfabrik. MATERIAIS E MÉTODOS: Foram confeccionados 11 corpos-de-prova cilíndricos para cada liga utilizada, sendo que a porção metálica foi obtida por fundição pela técnica da cera perdida, através de enceramentos padronizados com 4mm de altura por 4mm de diâmetro. A aplicação da cerâmica foi realizada segundo recomendações do fabricante, com auxílio de uma matriz de teflon que permitia sua padronização com as mesmas dimensões da porção metálica. Os corpos-de-prova foram submetidos
Applicability of the diffusion and simplified P3 theories for BWR pin-by-pin core analysis
International Nuclear Information System (INIS)
Tada, Kenichi; Yamamoto, Akio; Kitamura, Yasunori; Yamane, Yoshihiro; Watanabe, Masato; Noda, Hiroshi
2007-01-01
The pin-by-pin fine mesh core calculation method is considered as a candidate of next-generation core calculation method for BWR. In this study, the diffusion and the simplified P 3 (SP 3 ) theories are applied to the pin-by-pin core analysis of BWR. Performances of the diffusion and the SP 3 theories for cell-homogeneous pin-by-pin fine mesh BWR core analysis are evaluated through comparison with cell-heterogeneous detailed transport calculation by the method of characteristics (MOC). In this study, two-dimensional, 2x2 multi-assemblies geometry is used to compare the prediction accuracies of the diffusion and the SP 3 theories. The 2x2 multi- assemblies geometry consists of two types of 9x9 UO 2 assembly that have two different enrichment splittings. To mitigate the cell-homogenization error, the SPH method is applied for the pin-by-pin fine mesh calculation. The SPH method is a technique that reproduces a result of heterogeneous calculation by that of homogeneous calculation. The calculation results indicated that diffusion theory shows larger discrepancy than that of SP 3 theory on pin-wise fission rates. Furthermore, the accuracy of the diffusion theory would not be sufficient for the pin-by-pin fine mesh calculation. In contrast to the diffusion theory, the SP 3 theory shows much better accuracy on pin wise fission rates. Therefore, if the SP 3 theory is applied, the accuracy of the pin-by-pin fine mesh BWR core analysis will be higher and will be sufficient for production calculation. (author)
Gravitational effects in field gravitation theory
International Nuclear Information System (INIS)
Denisov, V.I.; Logunov, A.A.; Mestvirishvili, M.A.; Vlasov, A.A.
1979-01-01
The possibilities to describe various gravitation effects of field gravitation theory (FGT) are considered. Past-Newtonian approximation of the FGT has been constructed and on the basis of this approximation it has been shown that the field theory allows one to describe the whole set of experimental facts. The comparison of post-Newtonian parameters in FGT with those in the Einstein's theory makes it clear that these two; theories are undistinguishable from the viewpoint of any experiments, realized with post-Newtonian accuracy. Gravitational field of an island type source with spherically symmetrical distribution of matter and unstationary homogeneous model of Universe, which allows to describe the effect of cosmological red shift, are considered
Vitreous carbon mask substrate for X-ray lithography
Aigeldinger, Georg [Livermore, CA; Skala, Dawn M [Fremont, CA; Griffiths, Stewart K [Livermore, CA; Talin, Albert Alec [Livermore, CA; Losey, Matthew W [Livermore, CA; Yang, Chu-Yeu Peter [Dublin, CA
2009-10-27
The present invention is directed to the use of vitreous carbon as a substrate material for providing masks for X-ray lithography. The new substrate also enables a small thickness of the mask absorber used to pattern the resist, and this enables improved mask accuracy. An alternative embodiment comprised the use of vitreous carbon as a LIGA substrate wherein the VC wafer blank is etched in a reactive ion plasma after which an X-ray resist is bonded. This surface treatment provides a surface enabling good adhesion of the X-ray photoresist and subsequent nucleation and adhesion of the electrodeposited metal for LIGA mold-making while the VC substrate practically eliminates secondary radiation effects that lead to delamination of the X-ray resist form the substrate, the loss of isolated resist features, and the formation of a resist layer adjacent to the substrate that is insoluble in the developer.
Prevalencia de lesiones en gimnastas pertenecientes a la Liga de Gimnasia de Bogotá, D.C.
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Diego Fabricio Rodríguez-Camacho
2016-09-01
Full Text Available Introducción. La exigencia física en los gimnastas durante su formación puede traer consigo lesiones; la intensidad y cantidad de práctica en relación al nivel de competencia y grado de dificultad de los elementos hacen de este deporte uno de los que mayores lesiones produce. Objetivo. Estimar la prevalencia de lesiones y los factores correlacionados a estas en gimnastas pertenecientes a la Liga de Gimnasia de Bogotá, Colombia. Materiales y métodos. Estudio observacional, correlacional y con diseño transversal realizado en 19 gimnastas: nueve mayores de 14 años, nueve entre 15 y 19 y uno de 22 años. Se midió índice de masa corporal (IMC, peso corporal, talla, squat jump, contra movimiento, pliometría en miembros superiores, dinamometría de espalda y sit and reach; también se realizó una encuesta de prevalencia de lesiones. Resultados. 14 deportistas presentaron lesiones el último año. El lugar de lesión más prevalente fue codo con 24%, seguido de pie con 21%. El tipo de lesión más prevalente fue esguince con 31.6%, seguido por tendinopatía con 21%. No hubo correlación entre squat jump, contra movimiento, pliometría en miembros superiores, dinamometría de espalda y sit and reach. Conclusiones. Las variables edad, peso, IMC y duración del entrenamiento se correlacionan con la aparición de lesiones. Las mujeres sufren más lesiones en comparación con hombres.
Castilho, Anderson Almeida [UNESP
2009-01-01
O objetivo neste estudo foi avaliar a alteração dimensional provocada pelos procedimentos de soldagem nas infra-estruturas de próteses fixas impanto-suportadas por meio de análise de extensometria linear elétrica assim como se determinar a resistência flexão de dois tipos de juntas soldadas (Arco-Plasma e Laser) em liga Odontológica Co-Cr. Para tanto, estruturas metálicas foram fundidas pelo método de indução para pilares tipo micro-unit. Para esse estudo, foram investigados três grupos: Grup...
A new theory for X-ray diffraction.
Fewster, Paul F
2014-05-01
This article proposes a new theory of X-ray scattering that has particular relevance to powder diffraction. The underlying concept of this theory is that the scattering from a crystal or crystallite is distributed throughout space: this leads to the effect that enhanced scatter can be observed at the `Bragg position' even if the `Bragg condition' is not satisfied. The scatter from a single crystal or crystallite, in any fixed orientation, has the fascinating property of contributing simultaneously to many `Bragg positions'. It also explains why diffraction peaks are obtained from samples with very few crystallites, which cannot be explained with the conventional theory. The intensity ratios for an Si powder sample are predicted with greater accuracy and the temperature factors are more realistic. Another consequence is that this new theory predicts a reliability in the intensity measurements which agrees much more closely with experimental observations compared to conventional theory that is based on `Bragg-type' scatter. The role of dynamical effects (extinction etc.) is discussed and how they are suppressed with diffuse scattering. An alternative explanation for the Lorentz factor is presented that is more general and based on the capture volume in diffraction space. This theory, when applied to the scattering from powders, will evaluate the full scattering profile, including peak widths and the `background'. The theory should provide an increased understanding of the reliability of powder diffraction measurements, and may also have wider implications for the analysis of powder diffraction data, by increasing the accuracy of intensities predicted from structural models.
A design of optical modulation system with pixel-level modulation accuracy
Zheng, Shiwei; Qu, Xinghua; Feng, Wei; Liang, Baoqiu
2018-01-01
Vision measurement has been widely used in the field of dimensional measurement and surface metrology. However, traditional methods of vision measurement have many limits such as low dynamic range and poor reconfigurability. The optical modulation system before image formation has the advantage of high dynamic range, high accuracy and more flexibility, and the modulation accuracy is the key parameter which determines the accuracy and effectiveness of optical modulation system. In this paper, an optical modulation system with pixel level accuracy is designed and built based on multi-points reflective imaging theory and digital micromirror device (DMD). The system consisted of digital micromirror device, CCD camera and lens. Firstly we achieved accurate pixel-to-pixel correspondence between the DMD mirrors and the CCD pixels by moire fringe and an image processing of sampling and interpolation. Then we built three coordinate systems and calculated the mathematic relationship between the coordinate of digital micro-mirror and CCD pixels using a checkerboard pattern. A verification experiment proves that the correspondence error is less than 0.5 pixel. The results show that the modulation accuracy of system meets the requirements of modulation. Furthermore, the high reflecting edge of a metal circular piece can be detected using the system, which proves the effectiveness of the optical modulation system.
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Hua Li
2017-01-01
Full Text Available The injection and ionization of volatile organic compounds (VOA by an integrated chip is experimentally analyzed in this paper. The integrated chip consists of a needle-to-cylinder electrode mounting on the Polymethyl Methacrylate (PMMA substrate. The needle-to-cylinder electrode is designed and fabricated by Lithographie, Galvanoformung and Abformung (LIGA technology. In this paper, the needle is connected to a negative power supply of −5 kV and used as the cathode; the cylinder electrodes are composed of two arrays of cylinders and serve as the anode. The ionic wind is produced based on corona and glow discharges of needle-to-cylinder electrodes. The experimental setup is designed to observe the properties of the needle-to-cylinder discharge and prove its functions as an ion source and air pump. In summary, the main results are as follows: (1 the ionic wind velocity produced by the chip is about 0.79 m/s at an applied voltage of −3300 V; (2 acetic acid and ammonia water can be injected through the chip, which is proved by pH test paper; and (3 the current measured by a Faraday cup is about 10 pA for acetic acid and ammonia with an applied voltage of −3185 V. The integrated chip is promising for portable analytical instruments, such as ion mobility spectrometry (IMS, field asymmetric ion mobility spectrometry (FAIMS, and mass spectrometry (MS.
Matter power spectrum and the challenge of percent accuracy
Schneider, Aurel; Teyssier, Romain; Potter, Doug; Stadel, Joachim; Onions, Julian; Reed, Darren S.; Smith, Robert E.; Springel, Volker; Pearce, Frazer R.; Scoccimarro, Roman
2015-01-01
Future galaxy surveys require one percent precision in the theoretical knowledge of the power spectrum over a large range including very nonlinear scales. While this level of accuracy is easily obtained in the linear regime with perturbation theory, it represents a serious challenge for small scales where numerical simulations are required. In this paper we quantify the precision of present-day $N$-body methods, identifying main potential error sources from the set-up of initial conditions to...
dos Santos, Erich Belzunces; Tudesco, Ivanda de Souza Silva; Caboclo, Luis Otávio S F; Yacubian, Elza Márcia T
2011-10-01
To assess cognitive measures and impact of education on cognitive performance (CP) of low educational levels healthy adults (LELHA) on a Neuropsychological Protocol (NP) suggested by the Liga Brasileira de Epilepsia. 138 subjects from an Education Program for Adults divided into two, age and gender matched groups of 69 subjects, answered the NP: Group 1 (mean of 6.9 ± 2.95 months of formal education) and Group 2, 47.8 ± 10 months. Data were compared as z-scores. The mean IQ was 77.1 ± 5.50 and 79.4 ± 3.30 in Groups 1 and 2, respectively (p=0.001). Both performed below the normal curve and Group 1 worse than 2. CP correlated with schooling, especially executive functions (54.1% vs 36.2%) and language (52.9% vs 25.7%). LELHA showed significant cognitive impairment in verbal and visuospatial areas. If these results had been obtained in epilepsy patients they would be interpreted as global cognitive impairment.
Approximation methods in probability theory
Čekanavičius, Vydas
2016-01-01
This book presents a wide range of well-known and less common methods used for estimating the accuracy of probabilistic approximations, including the Esseen type inversion formulas, the Stein method as well as the methods of convolutions and triangle function. Emphasising the correct usage of the methods presented, each step required for the proofs is examined in detail. As a result, this textbook provides valuable tools for proving approximation theorems. While Approximation Methods in Probability Theory will appeal to everyone interested in limit theorems of probability theory, the book is particularly aimed at graduate students who have completed a standard intermediate course in probability theory. Furthermore, experienced researchers wanting to enlarge their toolkit will also find this book useful.
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Alexander G. Kerl
2011-04-01
Full Text Available This study analyzes the accuracy of forecasted target prices within analysts’ reports. We compute a measure for target price forecast accuracy that evaluates the ability of analysts to exactly forecast the ex-ante (unknown 12-month stock price. Furthermore, we determine factors that explain this accuracy. Target price accuracy is negatively related to analyst-specific optimism and stock-specific risk (measured by volatility and price-to-book ratio. However, target price accuracy is positively related to the level of detail of each report, company size and the reputation of the investment bank. The potential conflicts of interests between an analyst and a covered company do not bias forecast accuracy.
Error and Uncertainty in the Accuracy Assessment of Land Cover Maps
Sarmento, Pedro Alexandre Reis
Traditionally the accuracy assessment of land cover maps is performed through the comparison of these maps with a reference database, which is intended to represent the "real" land cover, being this comparison reported with the thematic accuracy measures through confusion matrixes. Although, these reference databases are also a representation of reality, containing errors due to the human uncertainty in the assignment of the land cover class that best characterizes a certain area, causing bias in the thematic accuracy measures that are reported to the end users of these maps. The main goal of this dissertation is to develop a methodology that allows the integration of human uncertainty present in reference databases in the accuracy assessment of land cover maps, and analyse the impacts that uncertainty may have in the thematic accuracy measures reported to the end users of land cover maps. The utility of the inclusion of human uncertainty in the accuracy assessment of land cover maps is investigated. Specifically we studied the utility of fuzzy sets theory, more precisely of fuzzy arithmetic, for a better understanding of human uncertainty associated to the elaboration of reference databases, and their impacts in the thematic accuracy measures that are derived from confusion matrixes. For this purpose linguistic values transformed in fuzzy intervals that address the uncertainty in the elaboration of reference databases were used to compute fuzzy confusion matrixes. The proposed methodology is illustrated using a case study in which the accuracy assessment of a land cover map for Continental Portugal derived from Medium Resolution Imaging Spectrometer (MERIS) is made. The obtained results demonstrate that the inclusion of human uncertainty in reference databases provides much more information about the quality of land cover maps, when compared with the traditional approach of accuracy assessment of land cover maps. None
The control of manual entry accuracy in management/engineering information systems, phase 1
Hays, Daniel; Nocke, Henry; Wilson, Harold; Woo, John, Jr.; Woo, June
1987-01-01
It was shown that clerical personnel can be tested for proofreading performance under simulated industrial conditions. A statistical study showed that errors in proofreading follow an extreme value probability theory. The study showed that innovative man/machine interfaces can be developed to improve and control accuracy during data entry.
Determination of the QCD Λ-parameter and the accuracy of perturbation theory at high energies
International Nuclear Information System (INIS)
Dalla Brida, Mattia; Fritzsch, Patrick; Korzec, Tomasz; Ramos, Alberto; Sint, Stefan; Sommer, Rainer; Humboldt-Universitaet, Berlin
2016-04-01
We discuss the determination of the strong coupling α_M_S(m_Z) or equivalently the QCD Λ-parameter. Its determination requires the use of perturbation theory in α_s(μ) in some scheme, s, and at some energy scale μ. The higher the scale μ the more accurate perturbation theory becomes, owing to asymptotic freedom. As one step in our computation of the Λ-parameter in three-flavor QCD, we perform lattice computations in a scheme which allows us to non-perturbatively reach very high energies, corresponding to α_s=0.1 and below. We find that (continuum) perturbation theory is very accurate there, yielding a three percent error in the Λ-parameter, while data around α_s∼0.2 is clearly insufficient to quote such a precision. It is important to realize that these findings are expected to be generic, as our scheme has advantageous properties regarding the applicability of perturbation theory.
Determination of the QCD Λ-parameter and the accuracy of perturbation theory at high energies
Energy Technology Data Exchange (ETDEWEB)
Dalla Brida, Mattia [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Fritzsch, Patrick [Univ. Autonoma de Madrid (Spain). Inst. de Fisica Teorica UAM/CSIC; Korzec, Tomasz [Wuppertal Univ. (Germany). Dept. of Physics; Ramos, Alberto [CERN - European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.; Sint, Stefan [Trinity College Dublin (Ireland). School of Mathematics; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Collaboration: ALPHA Collaboration
2016-04-15
We discuss the determination of the strong coupling α{sub MS}(m{sub Z}) or equivalently the QCD Λ-parameter. Its determination requires the use of perturbation theory in α{sub s}(μ) in some scheme, s, and at some energy scale μ. The higher the scale μ the more accurate perturbation theory becomes, owing to asymptotic freedom. As one step in our computation of the Λ-parameter in three-flavor QCD, we perform lattice computations in a scheme which allows us to non-perturbatively reach very high energies, corresponding to α{sub s}=0.1 and below. We find that (continuum) perturbation theory is very accurate there, yielding a three percent error in the Λ-parameter, while data around α{sub s}∼0.2 is clearly insufficient to quote such a precision. It is important to realize that these findings are expected to be generic, as our scheme has advantageous properties regarding the applicability of perturbation theory.
"Utilizing" signal detection theory.
Lynn, Spencer K; Barrett, Lisa Feldman
2014-09-01
What do inferring what a person is thinking or feeling, judging a defendant's guilt, and navigating a dimly lit room have in common? They involve perceptual uncertainty (e.g., a scowling face might indicate anger or concentration, for which different responses are appropriate) and behavioral risk (e.g., a cost to making the wrong response). Signal detection theory describes these types of decisions. In this tutorial, we show how incorporating the economic concept of utility allows signal detection theory to serve as a model of optimal decision making, going beyond its common use as an analytic method. This utility approach to signal detection theory clarifies otherwise enigmatic influences of perceptual uncertainty on measures of decision-making performance (accuracy and optimality) and on behavior (an inverse relationship between bias magnitude and sensitivity optimizes utility). A "utilized" signal detection theory offers the possibility of expanding the phenomena that can be understood within a decision-making framework. © The Author(s) 2014.
Accuracy of finite-difference harmonic frequencies in density functional theory.
Liu, Kuan-Yu; Liu, Jie; Herbert, John M
2017-07-15
Analytic Hessians are often viewed as essential for the calculation of accurate harmonic frequencies, but the implementation of analytic second derivatives is nontrivial and solution of the requisite coupled-perturbed equations engenders a sizable memory footprint for large systems, given that these equations are not required for energy and gradient calculations in density functional theory. Here, we benchmark the alternative approach to harmonic frequencies based on finite differences of analytic first derivatives, a procedure that is amenable to large-scale parallelization. Not only for absolute frequencies but also for isotopic and conformer-dependent frequency shifts in flexible molecules, we find that the finite-difference approach exhibits mean errors numbers. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Krasnoshchekov, Sergey V.; Schutski, Roman S.; Craig, Norman C.; Sibaev, Marat; Crittenden, Deborah L.
2018-02-01
Three dihalogenated methane derivatives (CH2F2, CH2FCl, and CH2Cl2) were used as model systems to compare and assess the accuracy of two different approaches for predicting observed fundamental frequencies: canonical operator Van Vleck vibrational perturbation theory (CVPT) and vibrational configuration interaction (VCI). For convenience and consistency, both methods employ the Watson Hamiltonian in rectilinear normal coordinates, expanding the potential energy surface (PES) as a Taylor series about equilibrium and constructing the wavefunction from a harmonic oscillator product basis. At the highest levels of theory considered here, fourth-order CVPT and VCI in a harmonic oscillator basis with up to 10 quanta of vibrational excitation in conjunction with a 4-mode representation sextic force field (SFF-4MR) computed at MP2/cc-pVTZ with replacement CCSD(T)/aug-cc-pVQZ harmonic force constants, the agreement between computed fundamentals is closer to 0.3 cm-1 on average, with a maximum difference of 1.7 cm-1. The major remaining accuracy-limiting factors are the accuracy of the underlying electronic structure model, followed by the incompleteness of the PES expansion. Nonetheless, computed and experimental fundamentals agree to within 5 cm-1, with an average difference of 2 cm-1, confirming the utility and accuracy of both theoretical models. One exception to this rule is the formally IR-inactive but weakly allowed through Coriolis-coupling H-C-H out-of-plane twisting mode of dichloromethane, whose spectrum we therefore revisit and reassign. We also investigate convergence with respect to order of CVPT, VCI excitation level, and order of PES expansion, concluding that premature truncation substantially decreases accuracy, although VCI(6)/SFF-4MR results are still of acceptable accuracy, and some error cancellation is observed with CVPT2 using a quartic force field.
Assessing the accuracy of different simplified frictional rolling contact algorithms
Vollebregt, E. A. H.; Iwnicki, S. D.; Xie, G.; Shackleton, P.
2012-01-01
This paper presents an approach for assessing the accuracy of different frictional rolling contact theories. The main characteristic of the approach is that it takes a statistically oriented view. This yields a better insight into the behaviour of the methods in diverse circumstances (varying contact patch ellipticities, mixed longitudinal, lateral and spin creepages) than is obtained when only a small number of (basic) circumstances are used in the comparison. The range of contact parameters that occur for realistic vehicles and tracks are assessed using simulations with the Vampire vehicle system dynamics (VSD) package. This shows that larger values for the spin creepage occur rather frequently. Based on this, our approach is applied to typical cases for which railway VSD packages are used. The results show that particularly the USETAB approach but also FASTSIM give considerably better results than the linear theory, Vermeulen-Johnson, Shen-Hedrick-Elkins and Polach methods, when compared with the 'complete theory' of the CONTACT program.
Joya Shaker, Mónica
2012-01-01
Este trabajo busca reflejar la influencia de la búsqueda de soberanía Palestina sobre las posiciones de la Liga de Estados Árabes en la Organización de las Naciones Unidas. Se hace énfasis en el análisis de este apoyo colectivo árabe a la causa palestina bajo el neorrealismo, los lineamientos teóricos propuestos por Kenneth Waltz.
Accuracy of Black and White College Students' In-Group and Out-Group Stereotypes.
Ryan, Carey S.
1996-01-01
Examined accuracy of black and of white students' in-group and out-group stereotypes by comparing judgments of stereotypicality and dispersion of black and of white first-year college students (N=100) with stereotypicality and dispersion of self-ratings provided by random samples of group members. Consistent with social identity theory,…
Theory and experiments in general relativity and other metric theories of gravity
International Nuclear Information System (INIS)
Ciufolini, I.
1984-01-01
In Chapter I, after an introduction to theories of gravity alternative to general relativity, metric theories, and the post-Newtonian parameterized (PNN) formalism, a new class of metric theories of gravity is defined. As a result the post-Newtonian approximation of the new theories is not described by the PPN formalism. In fact under the weak field and slow motion hypothesis, the post-Newtonian expression of the metric tensor contains an infinite set of new terms and correspondingly an infinite set of new PPN parameters. Chapter II, III, and IV are devoted to new experiments to test general relativity and other metric theories of gravity. In particular, in chapter IV, it is shown that two general relativistics effects, the Lense-Thirring and De Sitter-Fokker precessions of the nodal lines of an Earth artificial satellite are today detectable using high altitude laser ranged artificial satellites such as Lageos. The orbit of this satellite is known with unprecedented accuracy. The author then describes a method of measuring these relativistic precessions using Lageos together with another high altitude laser ranged similar satellite with appropriately chosen orbital parameters
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Sueli Soares dos Santos Batista
2000-12-01
Full Text Available Este artigo visa apresentar algumas reflexões sobre sociedade e educação pensadas a partir da Teoria Crítica que, especialmente, no pensamento de T. W. Adorno, postula a interpretação e a transformação da sociedade e do conhecimento por ela produzido como premissa básica de uma educação emancipatória. A crítica ao positivismo, a constatação das antinomias entre cultura e administração são instrumentos para a análise do construtivismo, da discussão sobre democratização do ensino e das formulações que estabelecem ligações imediatas entre relações interpessoais e democracia.This article discusses society and education based on the critical theory that, especially in the thinking of T. W. Adorno, postulates the interpretation and transformation of society and of the knowledge produced by it as basic premises of liberating education. A criticism of positivism and the perception of the contradictions between culture and administration are instruments for analyzing not only constructivism, but also for the discussion on the democratization of education and the formulations that establish immediate connections between interpersonal relations and democracy.
A finite element formulation for perturbation theory calculations
International Nuclear Information System (INIS)
Ozgener, B.; Kaluc, S.
2004-01-01
Full text: When the introduced change in the configuration of a nuclear system is neutronically not too significant, the use of the perturbation theory approximation ('the perturbation theory method' or PTM) is usually considered as an alternative to the recalculation of the effective multiplication factor (K eff ) of the modified system ('the diffusion theory method' or DTM) for the determination of the ensuing change in reactivity. In the DTM, the change in reactivity due to the introduced change can be calculated by the multigroup diffusion theory by performing two K eff determinations, one for the original and one for the modified system. The accuracy of this method is only limited by the approximations inherent in the multigroup diffusion theory and the numerical method employed for its solution. The error stemming from the numerical approximation can be nearly eliminated by utilizing a fine enough spatial mesh ad an 'exact' solution is nearly possible. Its basic disadvantage relative to the PTM is the necessity of a new K eff calculation for every change in the configuration no matter how small. On the other hand, if we use PTM, with an only one-time calculation of the flux and the adjoint flux of the original system, the change in reactivity due to any kind of perturbation can be approximately calculated using the changes in the cross section data in the perturbation theory reactivity formula. The accuracy of the PTM is restricted by the size and location of the induced change. In this work, our aim is to assess the accuracy of PTM relative to the DTM and determine criteria for the justification of its use. For all required solutions of the normal and adjoint multigroup diffusion equations, we choose the finite element method (FEM) as our numerical method and a 1-D cylindrical geometry model. The underlying theory is implemented in our FORTRAN program PERTURB. The validation of PERTURB is carried out via comparisons with analytical solutions for bare and
Ultra-Precise Assembly of Micro-Electromechanical Systems (MEMS) Components
Energy Technology Data Exchange (ETDEWEB)
Feddema, J.T.; Simon, R.; Polosky, M.; Christenson, T.
1999-04-01
This report summarizes a three year effort to develop an automated microassembly workcell for the assembly of LIGA (Lithography Galvonoforming Abforming) parts. Over the last several years, Sandia has developed processes for producing surface machined silicon and LIGA parts for use in weapons surety devices. Some of these parts have outside dimensions as small as 100 micron, and most all have submicron tolerances. Parts this small and precise are extremely difficult to assembly by hand. Therefore, in this project, we investigated the technologies required to develop a robotic workcell to assembly these parts. In particular, we concentrated on micro-grippers, visual servoing, micro-assembly planning, and parallel assembly. Three different micro-grippers were tested: a pneumatic probe, a thermally actuated polysilicon tweezer, and a LIGA fabricated tweezer. Visual servoing was used to accuracy position two parts relative to one another. Fourier optics methods were used to generate synthetic microscope images from CAD drawings. These synthetic images are used off-line to test image processing routines under varying magnifications and depths of field. They also provide reference image features which are used to visually servo the part to the desired position. We also investigated a new aspect of fine motion planning for the micro-domain. As parts approach 1-10 {micro}m or less in outside dimensions, interactive forces such as van der Waals and electrostatic forces become major factors which greatly change the assembly sequence and path plans. We developed the mathematics required to determine the goal regions for pick up, holding, and release of a micro-sphere being handled by a rectangular tool. Finally, we implemented and tested the ability to assemble an array of LIGA parts attached to two 3 inch diameter wafers. In this way, hundreds of parts can be assembled in parallel rather than assembling each part individually.
Superthin disintegration of 2s-level in light hydrogenlike atoms: theory and experiment
International Nuclear Information System (INIS)
Karshenbojm, S.G.; Kolachevskij, N.N.; Ivanov, V.G.; Fischer, M.; Fendel, P.; Hensch, T.W.
2006-01-01
Peculiar combination of superthin disintegrations in hydrogen and in D 21 = 8f hfs (2s)-f hfs (1s) similar light two-particle atoms depends slightly on nucleus structure and thus enables to compare theory with experiment sensitive to the high order quantum-electrodynamic corrections. Paper presents new theoretical and experimental results. The calculations deal with hydrogen, deuterium and helium-3 ion. The experiments were performed for 2s level superthin disintegration in hydrogen and deuterium the error of which dominates in D 21 difference. Theory and experiment are in line, and their accuracy is comparable with the accuracy of verifications of the quantum-and-electrodynamic theory of superthin disintegration in lepton atoms (muonium and positronium) [ru
The Bateman method for multichannel scattering theory
International Nuclear Information System (INIS)
Kim, Y. E.; Kim, Y. J.; Zubarev, A. L.
1997-01-01
Accuracy and convergence of the Bateman method are investigated for calculating the transition amplitude in multichannel scattering theory. This approximation method is applied to the calculation of elastic amplitude. The calculated results are remarkably accurate compared with those of exactly solvable multichannel model
Einstein-aether as a quantum effective field theory
International Nuclear Information System (INIS)
Withers, Benjamin
2009-01-01
The possibility that Lorentz symmetry is violated in gravitational processes is relatively unconstrained by experiment, in stark contrast with the level of accuracy to which Lorentz symmetry has been confirmed in the matter sector. One model of Lorentz violation in the gravitational sector is Einstein-aether theory, in which Lorentz symmetry is broken by giving a vacuum expectation value to a dynamical vector field. In this paper, we analyse the effective theory for quantized gravitational and aether perturbations. We show that this theory possesses a controlled effective expansion within dimensional regularization, that is, for any process there are a finite number of Feynman diagrams which will contribute to a given order of accuracy. We find that there is no log running of the 2-derivative phenomenological parameters, justifying the use of experimental constraints for these parameters obtained over many orders of magnitude in energy scale. Given the stringent experimental bounds on 2-derivative Lorentz-violating operators, we estimate the size of matter Lorentz violation which arises due to loop effects. This amounts to an estimation of the natural size of coefficients for Lorentz-violating dimension-6 matter operators, which in turn can be used to obtain a new bound on the 2-derivative parameters of this theory.
International Nuclear Information System (INIS)
Tchangnwa Nya, F; Ayadim, A; Germain, Ph; Amokrane, S
2012-01-01
We examine the question of the accuracy of the static correlation functions used as input in the mode coupling theory (MCT) of non-ergodic states in binary mixtures. We first consider hard-sphere mixtures and compute the static pair structure from the Ornstein-Zernike equations with the Percus-Yevick closure and more accurate ones that use bridge functions deduced from Rosenfeld’s fundamental measures functional. The corresponding MCT predictions for the non-ergodicity lines and the transitions between multiple glassy states are determined from the long-time limit of the density autocorrelation functions. We find that while the non-ergodicity transition line is not very sensitive to the input static structure, up to diameter ratios D 2 /D 1 = 10, quantitative differences exist for the transitions between different glasses. The discrepancies with the more accurate closures become even qualitative for sufficiently asymmetric mixtures. They are correlated with the incorrect behavior of the PY structure at high size asymmetry. From the example of ultra-soft potential it is argued that this issue is of general relevance beyond the hard-sphere model. (paper)
Estimating the Accuracy of the Return on Investment (ROI Performance Evaluations
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Alexei Botchkarev
2015-12-01
Full Text Available Return on Investment (ROI is one of the most popular performance measurement and evaluation metrics. ROI analysis (when applied correctly is a powerful tool in comparing solutions and making informed decisions on the acquisitions of information systems. The purpose of this study is to provide a systematic research of the accuracy of the ROI evaluations in the context of information systems implementations. Measurements theory and error analysis, specifically propagation of uncertainties methods, were used to derive analytical expressions for ROI errors. Monte Carlo simulation methodology was used to design and deliver a quantitative experiment to model costs and returns estimating errors and calculate ROI accuracies. Spreadsheet simulation (Microsoft Excel spreadsheets enhanced with Visual Basic for Applications was used to implement Monte Carlo simulations. The main contribution of the study is that this is the first systematic effort to evaluate ROI accuracy. Analytical expressions have been derived for estimating errors of the ROI evaluations. Results of the Monte Carlo simulation will help practitioners in making informed decisions based on explicitly stated factors influencing the ROI uncertainties.
International Nuclear Information System (INIS)
Liu, Zhouyu; Collins, Benjamin; Kochunas, Brendan; Downar, Thomas; Xu, Yunlin; Wu, Hongchun
2015-01-01
Highlights: • The CDP combines the benefits of the CPM’s efficiency and the MOC’s flexibility. • Boundary averaging reduces the computation effort with losing minor accuracy. • An analysis model is used to justify the choice of optimize averaging strategy. • Numerical results show the performance and accuracy. - Abstract: The method of characteristic direction probabilities (CDP) combines the benefits of the collision probability method (CPM) and the method of characteristics (MOC) for the solution of the integral form of the Botlzmann Transport Equation. By coupling only the fine regions traversed by the characteristic rays in a particular direction, the computational effort required to calculate the probability matrices and to solve the matrix system is considerably reduced compared to the CPM. Furthermore, boundary averaging is performed to reduce the storage and computation but the capability of dealing with complicated geometries is preserved since the same ray tracing information is used as in MOC. An analysis model for the outgoing angular flux is used to analyze a variety of outgoing angular flux averaging methods for the boundary and to justify the choice of optimize averaging strategy. The boundary average CDP method was then implemented in the Michigan PArallel Characteristic based Transport (MPACT) code to perform 2-D and 3-D transport calculations. The numerical results are given for different cases to show the effect of averaging on the outgoing angular flux, region scalar flux and the eigenvalue. Comparison of the results with the case with no averaging demonstrates that an angular dependent averaging strategy is possible for the CDP to improve its computational performance without compromising the achievable accuracy
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Erich Belzunces dos Santos
2011-10-01
Full Text Available OBJECTIVE: To assess cognitive measures and impact of education on cognitive performance (CP of low educational levels healthy adults (LELHA on a Neuropsychological Protocol (NP suggested by the Liga Brasileira de Epilepsia. METHOD: 138 subjects from an Education Program for Adults divided into two, age and gender matched groups of 69 subjects, answered the NP: Group 1 (mean of 6.9±2.95 months of formal education and Group 2, 47.8±10 months. Data were compared as z-scores. RESULTS: The mean IQ was 77.1±5.50 and 79.4±3.30 in Groups 1 and 2, respectively (p=0.001. Both performed below the normal curve and Group 1 worse than 2. CP correlated with schooling, especially executive functions (54.1% vs 36.2% and language (52.9% vs 25.7%. CONCLUSION: LELHA showed significant cognitive impairment in verbal and visuospatial areas. If these results had been obtained in epilepsy patients they would be interpreted as global cognitive impairment.
“UTILIZING” SIGNAL DETECTION THEORY
Lynn, Spencer K.; Barrett, Lisa Feldman
2014-01-01
What do inferring what a person is thinking or feeling, deciding to report a symptom to your doctor, judging a defendant’s guilt, and navigating a dimly lit room have in common? They involve perceptual uncertainty (e.g., a scowling face might indicate anger or concentration, which engender different appropriate responses), and behavioral risk (e.g., a cost to making the wrong response). Signal detection theory describes these types of decisions. In this tutorial we show how, by incorporating the economic concept of utility, signal detection theory serves as a model of optimal decision making, beyond its common use as an analytic method. This utility approach to signal detection theory highlights potentially enigmatic influences of perceptual uncertainty on measures of decision-making performance (accuracy and optimality) and on behavior (a functional relationship between bias and sensitivity). A “utilized” signal detection theory offers the possibility of expanding the phenomena that can be understood within a decision-making framework. PMID:25097061
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Daniela Castilio
2006-04-01
Full Text Available Misfit at the abutment-prosthetic cylinder interface can cause loss of preload, leading to loosening or fracture of gold and titanium screws. OBJECTIVES: To evaluate the influence of screw type, alloy, and cylinder position on marginal fit of implant frameworks before and after laser welding. METHODS: After Estheticone-like abutments were screwed to the implants, thirty plastic prosthetic cylinders were mounted and waxed-up to fifteen cylindrical bars. Each specimen had three interconnected prosthetic components. Five specimens were one-piece cast in titanium and five in cobalt-chromium alloy. On each specimen, tests were conducted with hexagonal titanium and slotted gold screws separately, performing a total of thirty tested screws. Measurements at the interfaces were performed using an optical microscope with 5mm accuracy. After sectioning, specimens were laser welded and new measurements were obtained. Data were submitted to a four-way ANOVA and Tukey's multiple comparisons test (alpha=0.05. RESULTS: Slotted and hexagonal screws did not present significant differences regarding to the fit of cylinders cast in titanium, either in one-piece casting framework or after laser welding. When slotted and hexagonal screws were tested on the cobalt-chromium specimens, statistically significant differences were found for the one-piece casting condition, with the slotted screws presenting better fit (24.13µm than the hexagonal screws (27.93 µm. Besides, no statistically significant differences were found after laser welding. CONCLUSIONS: 1 The use of different metal alloys do exert influence on the marginal fit, 2 The slotted and hexagonal screws play the exclusive role of fixing the prosthesis, and did not improve the fit of cylinders, and 3 cylinder position did not affect marginal fit values.A desadaptação na interface abutment-cilindro protético pode causar perda da pré-carga, levando ao afrouxamento ou fratura dos parafusos de ouro e tit
The quantum theory of measurement
Busch, Paul; Mittelstaedt, Peter
1996-01-01
The amazing accuracy in verifying quantum effects experimentally has recently renewed interest in quantum mechanical measurement theory. In this book the authors give within the Hilbert space formulation of quantum mechanics a systematic exposition of the quantum theory of measurement. Their approach includes the concepts of unsharp objectification and of nonunitary transformations needed for a unifying description of various detailed investigations. The book addresses advanced students and researchers in physics and philosophy of science. In this second edition Chaps. II-IV have been substantially rewritten. In particular, an insolubility theorem for the objectification problem has been formulated in full generality, which includes unsharp object observables and unsharp pointers.
Fundamental U-Theory of Time. Part 1
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Yuvraj J. Gopaul
2016-02-01
Full Text Available The Fundamental U-Theory of Time (Part 1 is an original theory that aims to unravel the mystery of what exactly is ‘time’. To date very few explanations, from the branches of physics or cosmology, have succeeded to provide an accurate and comprehensive depiction of time. Most explanations have only managed to provide partial understanding or at best, glimpses of its true nature. The U-Theory uses ‘Thought Experiments’ to uncover the determining characteristics of time. In part 1 of this theory, the focus is not on the mathematics as it is on the accuracy of the depiction of time. Moreover, it challenges current views on theoretical physics, particularly on the idea of ‘time travel’. Notably, it is a theory seeking to present a fresh approach for reviewing Einstein’s Theory of Relativity, while unlocking new pathways for upcoming research in the field of physics and cosmology.
Perspective: Fundamental aspects of time-dependent density functional theory
Energy Technology Data Exchange (ETDEWEB)
Maitra, Neepa T. [Department of Physics and Astronomy, Hunter College and the Physics Program at the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10065 (United States)
2016-06-14
In the thirty-two years since the birth of the foundational theorems, time-dependent density functional theory has had a tremendous impact on calculations of electronic spectra and dynamics in chemistry, biology, solid-state physics, and materials science. Alongside the wide-ranging applications, there has been much progress in understanding fundamental aspects of the functionals and the theory itself. This Perspective looks back to some of these developments, reports on some recent progress and current challenges for functionals, and speculates on future directions to improve the accuracy of approximations used in this relatively young theory.
¿Tienen los árbitros de fútbol influencia en los resultados de la liga española?
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Sala Garrido, Ramon
2009-01-01
Full Text Available RESUMEN El trabajo analiza los resultados de las temporadas 2002-03 a 2007-08 de la Liga Española de Primera División con el fin de determinar la influencia de los árbitros en los mismos, tanto desde el punto de vista del tiempo extra que añaden, como de las sanciones disciplinarias (faltas y tarjetas a los equipos. Se estudia también la influencia que sobre las decisiones del árbitro puede tener la afición del equipo local. Se concluye que no puede afirmarse que la exista influencia arbitral de forma generalizada, aunque algunos árbitros en concreto sí parecen influir en los resultados. El análisis permite también confirmar algo ya sabido, el escaso valor del tiempo extra para cambiar el resultado de un partido.ABSTRACT This paper analyses the results of the 2002-03 to 2007-08 seasons of the First Division Spanish Football League with the aim of determining the influence of referees in them, both from the point of view of the extra time they allow, as well as the disciplinary sanctions (fouls and cards given to the teams. The influence that the supporters of the local team may have over the referee’s decisions is also studied. The conclusion is that it is not possible to confirm the existence of referee influence in a general sense, although some specific referees do seem to have an influence on the results. This analysis also confirms something already known, which is the minimal value of extra time in changing the results of a match.
The Friction Theory for Viscosity Modeling
DEFF Research Database (Denmark)
Cisneros, Sergio; Zeberg-Mikkelsen, Claus Kjær; Stenby, Erling Halfdan
2001-01-01
, in the case when experimental information is available a more accurate modeling can be obtained by means of a simple tuning procedure. A tuned f-theory general model can deliver highly accurate viscosity modeling above the saturation pressure and good prediction of the liquid-phase viscosity at pressures......In this work the one-parameter friction theory (f-theory) general models have been extended to the viscosity prediction and modeling of characterized oils. It is demonstrated that these simple models, which take advantage of the repulsive and attractive pressure terms of cubic equations of state...... such as the SRK, PR and PRSV, can provide accurate viscosity prediction and modeling of characterized oils. In the case of light reservoir oils, whose properties are close to those of normal alkanes, the one-parameter f-theory general models can predict the viscosity of these fluids with good accuracy. Yet...
Structural reliability analysis under evidence theory using the active learning kriging model
Yang, Xufeng; Liu, Yongshou; Ma, Panke
2017-11-01
Structural reliability analysis under evidence theory is investigated. It is rigorously proved that a surrogate model providing only correct sign prediction of the performance function can meet the accuracy requirement of evidence-theory-based reliability analysis. Accordingly, a method based on the active learning kriging model which only correctly predicts the sign of the performance function is proposed. Interval Monte Carlo simulation and a modified optimization method based on Karush-Kuhn-Tucker conditions are introduced to make the method more efficient in estimating the bounds of failure probability based on the kriging model. Four examples are investigated to demonstrate the efficiency and accuracy of the proposed method.
High accuracy acoustic relative humidity measurement in duct flow with air.
van Schaik, Wilhelm; Grooten, Mart; Wernaart, Twan; van der Geld, Cees
2010-01-01
An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH) instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0-12 m/s with an error of ± 0.13 m/s, temperature 0-100 °C with an error of ± 0.07 °C and relative humidity 0-100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.
Perturbation theory for plasmonic modulation and sensing
Raman, Aaswath
2011-05-25
We develop a general perturbation theory to treat small parameter changes in dispersive plasmonic nanostructures and metamaterials. We specifically apply it to dielectric refractive index and metallic plasma frequency modulation in metal-dielectric nanostructures. As a numerical demonstration, we verify the theory\\'s accuracy against direct calculations for a system of plasmonic rods in air where the metal is defined by a three-pole fit of silver\\'s dielectric function. We also discuss new optical behavior related to plasma frequency modulation in such systems. Our approach provides new physical insight for the design of plasmonic devices for biochemical sensing and optical modulation and future active metamaterial applications. © 2011 American Physical Society.
fMRI evidence for a dual process account of the speed-accuracy tradeoff in decision-making.
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Jason Ivanoff
Full Text Available BACKGROUND: The speed and accuracy of decision-making have a well-known trading relationship: hasty decisions are more prone to errors while careful, accurate judgments take more time. Despite the pervasiveness of this speed-accuracy trade-off (SAT in decision-making, its neural basis is still unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using functional magnetic resonance imaging (fMRI we show that emphasizing the speed of a perceptual decision at the expense of its accuracy lowers the amount of evidence-related activity in lateral prefrontal cortex. Moreover, this speed-accuracy difference in lateral prefrontal cortex activity correlates with the speed-accuracy difference in the decision criterion metric of signal detection theory. We also show that the same instructions increase baseline activity in a dorso-medial cortical area involved in the internal generation of actions. CONCLUSIONS/SIGNIFICANCE: These findings suggest that the SAT is neurally implemented by modulating not only the amount of externally-derived sensory evidence used to make a decision, but also the internal urge to make a response. We propose that these processes combine to control the temporal dynamics of the speed-accuracy trade-off in decision-making.
Finite-size scaling theory and quantum hamiltonian Field theory: the transverse Ising model
International Nuclear Information System (INIS)
Hamer, C.J.; Barber, M.N.
1979-01-01
Exact results for the mass gap, specific heat and susceptibility of the one-dimensional transverse Ising model on a finite lattice are generated by constructing a finite matrix representation of the Hamiltonian using strong-coupling eigenstates. The critical behaviour of the limiting infinite chain is analysed using finite-size scaling theory. In this way, excellent estimates (to within 1/2% accuracy) are found for the critical coupling and the exponents α, ν and γ
Letícia Resende Davi
2010-01-01
A higienização das próteses parciais ou totais removíveis é fundamental para a durabilidade do tratamento e prevenção de patologias orais. O objetivo deste estudo foi avaliar o efeito de agentes higienizadores de prótese na cor, corrosão e rugosidade superficial do titânio c.p., ligas metálicas e resina acrílica termopolimerizável, simulando um período de 180 dias de higienização. Espécimes em formato de discos (12 mm x 3 mm) foram confeccionados em: titânio comercialmente puro (Tritan - Ti c...
Classical and non-classical effective medium theories: New perspectives
International Nuclear Information System (INIS)
Tsukerman, Igor
2017-01-01
Highlights: • Advanced non-asymptotic and nonlocal homogenization theories of metamaterials, valid in electrostatics and electrodynamics. • Classical theories (Clausius–Mossotti, Lorenz–Lorentz, Maxwell Garnett) fit well into the proposed framework. • Nonlocal effects can be included in the model, making order-of-magnitude accuracy improvements possible. • A challenging problem for future research is to determine what effective tensors are attainable for given constituents of a metamaterial. - Abstract: Future research in electrodynamics of periodic electromagnetic composites (metamaterials) can be expected to produce sophisticated homogenization theories valid for any composition and size of the lattice cell. The paper outlines a promising path in that direction, leading to non-asymptotic and nonlocal homogenization models, and highlights aspects of homogenization that are often overlooked: the finite size of the sample and the role of interface boundaries. Classical theories (e.g. Clausius–Mossotti, Maxwell Garnett), while originally derived from a very different set of ideas, fit well into the proposed framework. Nonlocal effects can be included in the model, making an order-of-magnitude accuracy improvements possible. One future challenge is to determine what effective parameters can or cannot be obtained for a given set of constituents of a metamaterial lattice cell, thereby delineating the possible from the impossible in metamaterial design.
Classical and non-classical effective medium theories: New perspectives
Energy Technology Data Exchange (ETDEWEB)
Tsukerman, Igor, E-mail: igor@uakron.edu
2017-05-18
Highlights: • Advanced non-asymptotic and nonlocal homogenization theories of metamaterials, valid in electrostatics and electrodynamics. • Classical theories (Clausius–Mossotti, Lorenz–Lorentz, Maxwell Garnett) fit well into the proposed framework. • Nonlocal effects can be included in the model, making order-of-magnitude accuracy improvements possible. • A challenging problem for future research is to determine what effective tensors are attainable for given constituents of a metamaterial. - Abstract: Future research in electrodynamics of periodic electromagnetic composites (metamaterials) can be expected to produce sophisticated homogenization theories valid for any composition and size of the lattice cell. The paper outlines a promising path in that direction, leading to non-asymptotic and nonlocal homogenization models, and highlights aspects of homogenization that are often overlooked: the finite size of the sample and the role of interface boundaries. Classical theories (e.g. Clausius–Mossotti, Maxwell Garnett), while originally derived from a very different set of ideas, fit well into the proposed framework. Nonlocal effects can be included in the model, making an order-of-magnitude accuracy improvements possible. One future challenge is to determine what effective parameters can or cannot be obtained for a given set of constituents of a metamaterial lattice cell, thereby delineating the possible from the impossible in metamaterial design.
Robust Backlash Estimation for Industrial Drive-Train Systems—Theory and Validation
DEFF Research Database (Denmark)
Papageorgiou, Dimitrios; Blanke, Mogens; Niemann, Hans Henrik
2018-01-01
Backlash compensation is used in modern machinetool controls to ensure high-accuracy positioning. When wear of a machine causes deadzone width to increase, high-accuracy control may be maintained if the deadzone is accurately estimated. Deadzone estimation is also an important parameter to indica......-of-the-art Siemens equipment. The experiments validate the theory and show that expected performance and robustness to parameter uncertainties are both achieved....
A proposal for limited criminal liability in high-accuracy endoscopic sinus surgery.
Voultsos, P; Casini, M; Ricci, G; Tambone, V; Midolo, E; Spagnolo, A G
2017-02-01
The aim of the present study is to propose legal reform limiting surgeons' criminal liability in high-accuracy and high-risk surgery such as endoscopic sinus surgery (ESS). The study includes a review of the medical literature, focusing on identifying and examining reasons why ESS carries a very high risk of serious complications related to inaccurate surgical manoeuvers and reviewing British and Italian legal theory and case-law on medical negligence, especially with regard to Italian Law 189/2012 (so called "Balduzzi" Law). It was found that serious complications due to inaccurate surgical manoeuvers may occur in ESS regardless of the skill, experience and prudence/diligence of the surgeon. Subjectivity should be essential to medical negligence, especially regarding high-accuracy surgery. Italian Law 189/2012 represents a good basis for the limitation of criminal liability resulting from inaccurate manoeuvres in high-accuracy surgery such as ESS. It is concluded that ESS surgeons should be relieved of criminal liability in cases of simple/ordinary negligence where guidelines have been observed. © Copyright by Società Italiana di Otorinolaringologia e Chirurgia Cervico-Facciale, Rome, Italy.
Comparisons between geometrical optics and Lorenz-Mie theory
Ungut, A.; Grehan, G.; Gouesbet, G.
1981-01-01
Both the Lorenz-Mie and geometrical optics theories are used in calculating the scattered light patterns produced by transparent spherical particles over a wide range of diameters, between 1.0 and 100 microns, and for the range of forward scattering angles from zero to 20 deg. A detailed comparison of the results shows the greater accuracy of the geometrical optics theory in the forward direction. Emphasis is given to the simultaneous sizing and velocimetry of particles by means of pedestal calibration methods.
International Nuclear Information System (INIS)
Chiu, Hueihuang.
1989-01-01
A theoretical method is being developed by which the structure of a radiation field can be predicted by a radiation potential theory, similar to a classical potential theory. The introduction of a scalar potential is justified on the grounds that the spectral intensity vector is irrotational. The vector is also solenoidal in the limits of a radiation field in complete radiative equilibrium or in a vacuum. This method provides an exact, elliptic type equation that will upgrade the accuracy and the efficiency of the current CFD programs required for the prediction of radiation and flow fields. A number of interesting results emerge from the present study. First, a steady state radiation field exhibits an optically modulated inverse square law distribution character. Secondly, the unsteady radiation field is structured with two conjugate scalar potentials. Each is governed by a Klein-Gordon equation with a frictional force and a restoring force. This steady potential field structure and the propagation of radiation potentials are consistent with the well known results of classical electromagnetic theory. The extension of the radiation potential theory for spray combustion and hypersonic flow is also recommended
Application of diffusion theory to neutral atom transport in fusion plasmas
International Nuclear Information System (INIS)
Hasan, M.Z.; Conn, R.W.; Pomraning, G.C.
1987-01-01
It is found that the energy dependent diffusion theory provides excellent accuracy in the modelling of transport of neutral atoms in fusion plasmas. Two reasons in particular explain the good accuracy. First, while the plasma is optically thick for low energy neutrals, it is optically thin for high energy neutrals and the diffusion theory with Marshak boundary conditions gives accurate results for an optically thin medium, even for small values of c, the ratio of the scattering cross-section to the total cross-section. Second, the effective value of c at low energy is very close to 1 because of the downscattering via collisions of high energy neutrals. The first reason is proven computationally and theoretically by solving the transport equation in a power series in c and solving the diffusion equation with 'general' Marshak boundary conditions. The second reason is established numerically by comparing the results from a one-dimensional, general geometry, multigroup diffusion theory code, written for this purpose, with the results obtained using the transport code ANISN. Earlier studies comparing one-speed diffusion and transport theory indicated that the diffusion theory would be inaccurate. A detailed analysis shows that this conclusion is limited to a very specific case. Surprisingly, for a very wide range of conditions and when energy dependence is included, the diffusion theory is highly accurate. (author)
Flame acceleration due to wall friction: Accuracy and intrinsic limitations of the formulations
Demirgok, Berk; Sezer, Hayri; Akkerman, V.'Yacheslav
2015-11-01
The analytical formulations on the premixed flame acceleration induced by wall friction in two-dimensional (2D) channels [Bychkov et al., Phys. Rev. E 72 (2005) 046307] and cylindrical tubes [Akkerman et al., Combust. Flame 145 (2006) 206] are revisited. Specifically, pipes with one end closed are considered, with a flame front propagating from the closed pipe end to the open one. The original studies provide the analytical formulas for the basic flame and fluid characteristics such as the flame acceleration rate, the flame shape and its propagation speed, as well as the flame-generated flow velocity profile. In the present work, the accuracy of these approaches is verified, computationally, and the intrinsic limitations and validity domains of the formulations are identified. Specifically, the error diagrams are presented to demonstrate how the accuracy of the formulations depends on the thermal expansion in the combustion process and the Reynolds number associated with the flame propagation. It is shown that the 2D theory is accurate enough for a wide range of parameters. In contrast, the zeroth-order approximation for the cylindrical configuration appeared to be quite inaccurate and had to be revisited. It is subsequently demonstrated that the first-order approximation for the cylindrical geometry is very accurate for realistically large thermal expansions and Reynolds numbers. Consequently, unlike the zeroth-order approach, the first-order formulation can constitute a backbone for the comprehensive theory of the flame acceleration and detonation initiation in cylindrical tubes. Cumulatively, the accuracy of the formulations deteriorates with the reduction of the Reynolds number and thermal expansion.
ONETEP: linear-scaling density-functional theory with plane-waves
International Nuclear Information System (INIS)
Haynes, P D; Mostof, A A; Skylaris, C-K; Payne, M C
2006-01-01
This paper provides a general overview of the methodology implemented in onetep (Order-N Electronic Total Energy Package), a parallel density-functional theory code for largescale first-principles quantum-mechanical calculations. The distinctive features of onetep are linear-scaling in both computational effort and resources, obtained by making well-controlled approximations which enable simulations to be performed with plane-wave accuracy. Titanium dioxide clusters of increasing size designed to mimic surfaces are studied to demonstrate the accuracy and scaling of onetep
Application of diffusion theory to neutral atom transport in fusion plasmas
International Nuclear Information System (INIS)
Hasan, M.Z.; Conn, R.W.; Pomraning, G.C.
1986-05-01
It is found that energy dependent diffusion theory provides excellent accuracy in the modelling of transport of neutral atoms in fusion plasmas. Two reasons in particular explain the good accuracy. First, while the plasma is optically thick for low energy neutrals, it is optically thin for high energy neutrals and diffusion theory with Marshak boundary conditions gives accurate results for an optically thin medium even for small values of 'c', the ratio of the scattering to the total cross section. Second, the effective value of 'c' at low energy becomes very close to one due to the down-scattering via collisions of high energy neutrals. The first reason is proven both computationally and theoretically by solving the transport equation in a power series in 'c' and the diffusion equation with 'general' Marshak boundary conditions. The second reason is established numerically by comparing the results from a one-dimensional, general geometry, multigroup diffusion theory code, written for this purpose, with the results obtained using the transport code ANISN
Measurement Errors and Uncertainties Theory and Practice
Rabinovich, Semyon G
2006-01-01
Measurement Errors and Uncertainties addresses the most important problems that physicists and engineers encounter when estimating errors and uncertainty. Building from the fundamentals of measurement theory, the author develops the theory of accuracy of measurements and offers a wealth of practical recommendations and examples of applications. This new edition covers a wide range of subjects, including: - Basic concepts of metrology - Measuring instruments characterization, standardization and calibration -Estimation of errors and uncertainty of single and multiple measurements - Modern probability-based methods of estimating measurement uncertainty With this new edition, the author completes the development of the new theory of indirect measurements. This theory provides more accurate and efficient methods for processing indirect measurement data. It eliminates the need to calculate the correlation coefficient - a stumbling block in measurement data processing - and offers for the first time a way to obtain...
Stability and accuracy of metamemory in adulthood and aging: a longitudinal analysis.
McDonald-Miszczak, L; Hertzog, C; Hultsch, D F
1995-12-01
The stability and accuracy of memory perceptions in 2 longitudinal samples was examined. Sample 1 consisted of 231 adults (22-78 years) tested twice over 2 years. Sample 2 consisted of 234 adults (55-86 years) tested 3 times over 6 years. Measures of perceived and actual memory change were obtained. A primary focus was whether perceptions of memory change stem from application of an implicit theory about aging and memory or from accurate monitoring of actual changes in performance. Individual differences in metamemory were highly stable over time. Results suggested at least some accurate monitoring of memory in Sample 2, in which actual change was greatest. However the overall pattern of results is largely consistent with predictions derived from an implicit theory hypothesis.
Design and accuracy analysis of a metamorphic CNC flame cutting machine for ship manufacturing
Hu, Shenghai; Zhang, Manhui; Zhang, Baoping; Chen, Xi; Yu, Wei
2016-09-01
The current research of processing large size fabrication holes on complex spatial curved surface mainly focuses on the CNC flame cutting machines design for ship hull of ship manufacturing. However, the existing machines cannot meet the continuous cutting requirements with variable pass conditions through their fixed configuration, and cannot realize high-precision processing as the accuracy theory is not studied adequately. This paper deals with structure design and accuracy prediction technology of novel machine tools for solving the problem of continuous and high-precision cutting. The needed variable trajectory and variable pose kinematic characteristics of non-contact cutting tool are figured out and a metamorphic CNC flame cutting machine designed through metamorphic principle is presented. To analyze kinematic accuracy of the machine, models of joint clearances, manufacturing tolerances and errors in the input variables and error models considering the combined effects are derived based on screw theory after establishing ideal kinematic models. Numerical simulations, processing experiment and trajectory tracking experiment are conducted relative to an eccentric hole with bevels on cylindrical surface respectively. The results of cutting pass contour and kinematic error interval which the position error is from-0.975 mm to +0.628 mm and orientation error is from-0.01 rad to +0.01 rad indicate that the developed machine can complete cutting process continuously and effectively, and the established kinematic error models are effective although the interval is within a `large' range. It also shows the matching property between metamorphic principle and variable working tasks, and the mapping correlation between original designing parameters and kinematic errors of machines. This research develops a metamorphic CNC flame cutting machine and establishes kinematic error models for accuracy analysis of machine tools.
Association theories for complex thermodynamics
DEFF Research Database (Denmark)
Kontogeorgis, Georgios; Rafiqul Gani
2013-01-01
of this review is two-fold: first to illustrate some of the significant capabilities of these association theories and why indeed they have already been extensively used and are expected to find even more applications in the future. The second and most important aspect of this review is to outline many...... applications. While specialized models can handle different cases, even complex ones, with the advent of powerful theories and computers there is the hope that a single or a few models could be suitable for a general modeling of complex thermodynamics. After more than 100 years with active use of thermodynamic...... models, we have now come to the understanding that simple one-fluid theories like the cubic equations of state or the various forms of local composition models will never be able to model a wide range of complex systems with sufficient accuracy. While various modern approaches have appeared, one very...
Particle transport methods for LWR dosimetry developed by the Penn State transport theory group
International Nuclear Information System (INIS)
Haghighat, A.; Petrovic, B.
1997-01-01
This paper reviews advanced particle transport theory methods developed by the Penn State Transport Theory Group (PSTTG) over the past several years. These methods have been developed in response to increasing needs for accuracy of results and for three-dimensional modeling of nuclear systems
An integrated theory of attention and decision making in visual signal detection.
Smith, Philip L; Ratcliff, Roger
2009-04-01
The simplest attentional task, detecting a cued stimulus in an otherwise empty visual field, produces complex patterns of performance. Attentional cues interact with backward masks and with spatial uncertainty, and there is a dissociation in the effects of these variables on accuracy and on response time. A computational theory of performance in this task is described. The theory links visual encoding, masking, spatial attention, visual short-term memory (VSTM), and perceptual decision making in an integrated dynamic framework. The theory assumes that decisions are made by a diffusion process driven by a neurally plausible, shunting VSTM. The VSTM trace encodes the transient outputs of early visual filters in a durable form that is preserved for the time needed to make a decision. Attention increases the efficiency of VSTM encoding, either by increasing the rate of trace formation or by reducing the delay before trace formation begins. The theory provides a detailed, quantitative account of attentional effects in spatial cuing tasks at the level of response accuracy and the response time distributions. (c) 2009 APA, all rights reserved
2013-12-13
8 U.S. Army Field Artillery Operations ............................................................................ 8 Geodesy ...Experts in this field of study have a full working knowledge of geodesy and the theory that allows mensuration to surpass the level of accuracy achieved...desired. (2) Fire that is intended to achieve the desired result on target.”6 Geodesy : “that branch of applied mathematics which determines by observation
Statistical Theory of the Vector Random Decrement Technique
DEFF Research Database (Denmark)
Asmussen, J. C.; Brincker, Rune; Ibrahim, S. R.
1999-01-01
decays. Due to the speed and/or accuracy of the Vector Random Decrement technique, it was introduced as an attractive alternative to the Random Decrement technique. In this paper, the theory of the Vector Random Decrement technique is extended by applying a statistical description of the stochastic...
Yu, Haoyu S; He, Xiao; Truhlar, Donald G
2016-03-08
Kohn-Sham density functional theory is widely used for applications of electronic structure theory in chemistry, materials science, and condensed-matter physics, but the accuracy depends on the quality of the exchange-correlation functional. Here, we present a new local exchange-correlation functional called MN15-L that predicts accurate results for a broad range of molecular and solid-state properties including main-group bond energies, transition metal bond energies, reaction barrier heights, noncovalent interactions, atomic excitation energies, ionization potentials, electron affinities, total atomic energies, hydrocarbon thermochemistry, and lattice constants of solids. The MN15-L functional has the same mathematical form as a previous meta-nonseparable gradient approximation exchange-correlation functional, MN12-L, but it is improved because we optimized it against a larger database, designated 2015A, and included smoothness restraints; the optimization has a much better representation of transition metals. The mean unsigned error on 422 chemical energies is 2.32 kcal/mol, which is the best among all tested functionals, with or without nonlocal exchange. The MN15-L functional also provides good results for test sets that are outside the training set. A key issue is that the functional is local (no nonlocal exchange or nonlocal correlation), which makes it relatively economical for treating large and complex systems and solids. Another key advantage is that medium-range correlation energy is built in so that one does not need to add damped dispersion by molecular mechanics in order to predict accurate noncovalent binding energies. We believe that the MN15-L functional should be useful for a wide variety of applications in chemistry, physics, materials science, and molecular biology.
International Nuclear Information System (INIS)
Wang Chenyang; Harrington, Jim; Preskill, John
2003-01-01
We study the ±J random-plaquette Z 2 gauge model (RPGM) in three spatial dimensions, a three-dimensional analog of the two-dimensional ±J random-bond Ising model (RBIM). The model is a pure Z 2 gauge theory in which randomly chosen plaquettes (occurring with concentration p) have couplings with the 'wrong sign' so that magnetic flux is energetically favored on these plaquettes. Excitations of the model are one-dimensional 'flux tubes' that terminate at 'magnetic monopoles' located inside lattice cubes that contain an odd number of wrong-sign plaquettes. Electric confinement can be driven by thermal fluctuations of the flux tubes, by the quenched background of magnetic monopoles, or by a combination of the two. Like the RBIM, the RPGM has enhanced symmetry along a 'Nishimori line' in the p-T plane (where T is the temperature). The critical concentration p c of wrong-sign plaquettes at the confinement-Higgs phase transition along the Nishimori line can be identified with the accuracy threshold for robust storage of quantum information using topological error-correcting codes: if qubit phase errors, qubit bit-flip errors, and errors in the measurement of local check operators all occur at rates below p c , then encoded quantum information can be protected perfectly from damage in the limit of a large code block. Through Monte-Carlo simulations, we measure p c0 , the critical concentration along the T=0 axis (a lower bound on p c ), finding p c0 =.0293±.0002. We also measure the critical concentration of antiferromagnetic bonds in the two-dimensional RBIM on the T=0 axis, finding p c0 =.1031±.0001. Our value of p c0 is incompatible with the value of p c =.1093±.0002 found in earlier numerical studies of the RBIM, in disagreement with the conjecture that the phase boundary of the RBIM is vertical (parallel to the T axis) below the Nishimori line. The model can be generalized to a rank-r antisymmetric tensor field in d dimensions, in the presence of quenched
New numerical methods for quantum field theories on the continuum
Energy Technology Data Exchange (ETDEWEB)
Emirdag, P.; Easter, R.; Guralnik, G.S.; Hahn, S.C
2000-03-01
The Source Galerkin Method is a new numerical technique that is being developed to solve Quantum Field Theories on the continuum. It is not based on Monte Carlo techniques and has a measure to evaluate relative errors. It promises to increase the accuracy and speed of calculations, and takes full advantage of symmetries of the theory. The application of this method to the non-linear {sigma} model is outlined.
High Accuracy Acoustic Relative Humidity Measurement inDuct Flow with Air
Directory of Open Access Journals (Sweden)
Cees van der Geld
2010-08-01
Full Text Available An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0–12 m/s with an error of ±0.13 m/s, temperature 0–100 °C with an error of ±0.07 °C and relative humidity 0–100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.
International Nuclear Information System (INIS)
Zhang, M.; Ibekwe, S.; Li, G.; Pang, S.S.; Lian, K.
2006-01-01
The Pressurized Water Reactors (PWRs in Figure 1) were originally developed for naval propulsion purposes, and then adapted to land-based applications. It has three parts: the reactor coolant system, the steam generator and the condenser. The Steam generator (a yellow area in Figure 1) is a shell and tube heat exchanger with high-pressure primary water passing through the tube side and lower pressure secondary feed water as well as steam passing through the shell side. Therefore, a key issue in increasing the efficiency of heat exchanger is to improve the design of steam generator, which is directly translated into economic benefits. The past research works show that the presence of a pin-fin array in a channel enhances the heat transfer significantly. Hence, using microfabrication techniques, such as LIGA, micro-molding or electroplating, some special microstructures can be fabricated around the tubes in the heat exchanger to increase the heat-exchanging efficiency and reduce the overall size of the heat-exchanger for the given heat transfer rates. In this paper, micro-pin fins of different densities made of SU-8 photoresist are fabricated and studied to evaluate overall heat transfer efficiency. The results show that there is an optimized micro pin-fin configuration that has the best overall heat transfer effects
Bond-order potentials: Theory and implementation
International Nuclear Information System (INIS)
Horsfield, A.P.; Bratkovsky, A.M.; Fearn, M.; Pettifor, D.G.; Aoki, M.
1996-01-01
The background theory and the details required for implementation of bond-order potentials are presented in a systematic fashion. The theory is an O(N) implementation of tight binding that is naturally parallelizable. Further, it is straightforward to show how the lowest-order approximation to the two-site expansion can reproduce the Tersoff potential. The accuracy of the forces is demonstrated by means of constant-energy molecular dynamics, for which the energy is found to be very well conserved. Thus, the method is both an efficient computational method and a useful analytic tool for the atomistic simulation of materials. copyright 1996 The American Physical Society
Modeling of hydrogen Stark line shapes with kinetic theory methods
Rosato, J.; Capes, H.; Stamm, R.
2012-12-01
The unified formalism for Stark line shapes is revisited and extended to non-binary interactions between an emitter and the surrounding perturbers. The accuracy of this theory is examined through comparisons with ab initio numerical simulations.
Spoelman, Marianne; Verspoor, Marjolijn
Within a Dynamic System Theory (DST) approach, it is assumed that language is in a constant flux, but that differences in the degree of variability can give insight into the developmental process. This longitudinal case study focuses on intra-individual variability in accuracy rates and complexity
Scoring and Classifying Examinees Using Measurement Decision Theory
Directory of Open Access Journals (Sweden)
Lawrence M. Rudner
2009-04-01
Full Text Available This paper describes and evaluates the use of measurement decision theory (MDT to classify examinees based on their item response patterns. The model has a simple framework that starts with the conditional probabilities of examinees in each category or mastery state responding correctly to each item. The presented evaluation investigates: (1 the classification accuracy of tests scored using decision theory; (2 the effectiveness of different sequential testing procedures; and (3 the number of items needed to make a classification. A large percentage of examinees can be classified accurately with very few items using decision theory. A Java Applet for self instruction and software for generating, calibrating and scoring MDT data are provided.
Thermodynamics and proton activities of protic ionic liquids with quantum cluster equilibrium theory
Ingenmey, Johannes; von Domaros, Michael; Perlt, Eva; Verevkin, Sergey P.; Kirchner, Barbara
2018-05-01
We applied the binary Quantum Cluster Equilibrium (bQCE) method to a number of alkylammonium-based protic ionic liquids in order to predict boiling points, vaporization enthalpies, and proton activities. The theory combines statistical thermodynamics of van-der-Waals-type clusters with ab initio quantum chemistry and yields the partition functions (and associated thermodynamic potentials) of binary mixtures over a wide range of thermodynamic phase points. Unlike conventional cluster approaches that are limited to the prediction of thermodynamic properties, dissociation reactions can be effortlessly included into the bQCE formalism, giving access to ionicities, as well. The method is open to quantum chemical methods at any level of theory, but combination with low-cost composite density functional theory methods and the proposed systematic approach to generate cluster sets provides a computationally inexpensive and mostly parameter-free way to predict such properties at good-to-excellent accuracy. Boiling points can be predicted within an accuracy of 50 K, reaching excellent accuracy for ethylammonium nitrate. Vaporization enthalpies are predicted within an accuracy of 20 kJ mol-1 and can be systematically interpreted on a molecular level. We present the first theoretical approach to predict proton activities in protic ionic liquids, with results fitting well into the experimentally observed correlation. Furthermore, enthalpies of vaporization were measured experimentally for some alkylammonium nitrates and an excellent linear correlation with vaporization enthalpies of their respective parent amines is observed.
POTENCIALIDADE DO ELEMENTO TÓXICO BERÍLIO, USADO EM PRÓTESES DENTÁRIAS
Directory of Open Access Journals (Sweden)
ROLLO João Manuel Domingos de Almeida
1997-01-01
Full Text Available Neste trabalho, foi estudado o efeito do berílio sobre a microestrutura e a temperatura de fusão em ligas Ni-Cr-Mo-Co e suas propriedades de corrosão. O estudo consistiu na obtenção das diversas ligas através de fusão sob vácuo, seguidas de forjamento em condições industriais. Após o forjamento, as ligas foram tratadas termicamente em diversas temperaturas e resfriadas em água, ar e forno. Nas ligas Ni-Cr-Mo-Co, a presença do Be altera a microestrutura, proporcionando a formação de fases intermetálicas. Foi constatado que, nas ligas estudadas, o Be abaixa a temperatura de fusão e as torna susceptíveis à corrosão por pite
Evaluating hydrological model performance using information theory-based metrics
The accuracy-based model performance metrics not necessarily reflect the qualitative correspondence between simulated and measured streamflow time series. The objective of this work was to use the information theory-based metrics to see whether they can be used as complementary tool for hydrologic m...
Wang, Biao; Yu, Xiaofen; Li, Qinzhao; Zheng, Yu
2008-10-01
The paper aiming at the influence factor of round grating dividing error, rolling-wheel produce eccentricity and surface shape errors provides an amendment method based on rolling-wheel to get the composite error model which includes all influence factors above, and then corrects the non-circle measurement angle error of the rolling-wheel. We make soft simulation verification and have experiment; the result indicates that the composite error amendment method can improve the diameter measurement accuracy with rolling-wheel theory. It has wide application prospect for the measurement accuracy higher than 5 μm/m.
A non-asymptotic homogenization theory for periodic electromagnetic structures.
Tsukerman, Igor; Markel, Vadim A
2014-08-08
Homogenization of electromagnetic periodic composites is treated as a two-scale problem and solved by approximating the fields on both scales with eigenmodes that satisfy Maxwell's equations and boundary conditions as accurately as possible. Built into this homogenization methodology is an error indicator whose value characterizes the accuracy of homogenization. The proposed theory allows one to define not only bulk, but also position-dependent material parameters (e.g. in proximity to a physical boundary) and to quantify the trade-off between the accuracy of homogenization and its range of applicability to various illumination conditions.
Energy Technology Data Exchange (ETDEWEB)
Kelly, Aaron; Markland, Thomas E., E-mail: tmarkland@stanford.edu [Department of Chemistry, Stanford University, Stanford, California 94305 (United States); Brackbill, Nora [Department of Physics, Stanford University, Stanford, California 94305 (United States)
2015-03-07
In this article, we show how Ehrenfest mean field theory can be made both a more accurate and efficient method to treat nonadiabatic quantum dynamics by combining it with the generalized quantum master equation framework. The resulting mean field generalized quantum master equation (MF-GQME) approach is a non-perturbative and non-Markovian theory to treat open quantum systems without any restrictions on the form of the Hamiltonian that it can be applied to. By studying relaxation dynamics in a wide range of dynamical regimes, typical of charge and energy transfer, we show that MF-GQME provides a much higher accuracy than a direct application of mean field theory. In addition, these increases in accuracy are accompanied by computational speed-ups of between one and two orders of magnitude that become larger as the system becomes more nonadiabatic. This combination of quantum-classical theory and master equation techniques thus makes it possible to obtain the accuracy of much more computationally expensive approaches at a cost lower than even mean field dynamics, providing the ability to treat the quantum dynamics of atomistic condensed phase systems for long times.
Kelly, Aaron; Brackbill, Nora; Markland, Thomas E
2015-03-07
In this article, we show how Ehrenfest mean field theory can be made both a more accurate and efficient method to treat nonadiabatic quantum dynamics by combining it with the generalized quantum master equation framework. The resulting mean field generalized quantum master equation (MF-GQME) approach is a non-perturbative and non-Markovian theory to treat open quantum systems without any restrictions on the form of the Hamiltonian that it can be applied to. By studying relaxation dynamics in a wide range of dynamical regimes, typical of charge and energy transfer, we show that MF-GQME provides a much higher accuracy than a direct application of mean field theory. In addition, these increases in accuracy are accompanied by computational speed-ups of between one and two orders of magnitude that become larger as the system becomes more nonadiabatic. This combination of quantum-classical theory and master equation techniques thus makes it possible to obtain the accuracy of much more computationally expensive approaches at a cost lower than even mean field dynamics, providing the ability to treat the quantum dynamics of atomistic condensed phase systems for long times.
A New Error Analysis and Accuracy Synthesis Method for Shoe Last Machine
Directory of Open Access Journals (Sweden)
Bian Xiangjuan
2014-05-01
Full Text Available In order to improve the manufacturing precision of the shoe last machine, a new error-computing model has been put forward to. At first, Based on the special topological structure of the shoe last machine and multi-rigid body system theory, a spatial error-calculating model of the system was built; Then, the law of error distributing in the whole work space was discussed, and the maximum error position of the system was found; At last, The sensitivities of error parameters were analyzed at the maximum position and the accuracy synthesis was conducted by using Monte Carlo method. Considering the error sensitivities analysis, the accuracy of the main parts was distributed. Results show that the probability of the maximal volume error less than 0.05 mm of the new scheme was improved from 0.6592 to 0.7021 than the probability of the old scheme, the precision of the system was improved obviously, the model can be used for the error analysis and accuracy synthesis of the complex multi- embranchment motion chain system, and to improve the system precision of manufacturing.
Center-vortex dominance after dimensional reduction of SU(2) lattice gauge theory
Gattnar, J.; Langfeld, K.; Schafke, A.; Reinhardt, H.
2000-01-01
The high-temperature phase of SU(2) Yang-Mills theory is addressed by means of dimensional reduction with a special emphasis on the properties of center vortices. For this purpose, the vortex vacuum which arises from center projection is studied in pure 3-dimensional Yang-Mills theory as well as in the 3-dimensional adjoint Higgs model which describes the high temperature phase of the 4-dimensional SU(2) gauge theory. We find center-dominance within the numerical accuracy of 10%.
Memory for performance feedback :a test of three self- motivation theories
Donlin, Joanne Mac
1990-01-01
The current study tests the adequacy of three self-motive theories to predict recall of performance feedback, memory sensitivity, and ratings of perceived accuracy. Self-enhancement (Jones, 1973) predicts individuals are motivated to maintain their self-esteem. Individuals will therefore recall positive relative to negative feedback and will rate positive feedback as more accurate. Self-consistency theory (Swann, 1985) predicts individuals are motivated to maintain their self-conceptions. The...
Meditation experience predicts introspective accuracy.
Directory of Open Access Journals (Sweden)
Kieran C R Fox
Full Text Available The accuracy of subjective reports, especially those involving introspection of one's own internal processes, remains unclear, and research has demonstrated large individual differences in introspective accuracy. It has been hypothesized that introspective accuracy may be heightened in persons who engage in meditation practices, due to the highly introspective nature of such practices. We undertook a preliminary exploration of this hypothesis, examining introspective accuracy in a cross-section of meditation practitioners (1-15,000 hrs experience. Introspective accuracy was assessed by comparing subjective reports of tactile sensitivity for each of 20 body regions during a 'body-scanning' meditation with averaged, objective measures of tactile sensitivity (mean size of body representation area in primary somatosensory cortex; two-point discrimination threshold as reported in prior research. Expert meditators showed significantly better introspective accuracy than novices; overall meditation experience also significantly predicted individual introspective accuracy. These results suggest that long-term meditators provide more accurate introspective reports than novices.
Improving orbit prediction accuracy through supervised machine learning
Peng, Hao; Bai, Xiaoli
2018-05-01
Due to the lack of information such as the space environment condition and resident space objects' (RSOs') body characteristics, current orbit predictions that are solely grounded on physics-based models may fail to achieve required accuracy for collision avoidance and have led to satellite collisions already. This paper presents a methodology to predict RSOs' trajectories with higher accuracy than that of the current methods. Inspired by the machine learning (ML) theory through which the models are learned based on large amounts of observed data and the prediction is conducted without explicitly modeling space objects and space environment, the proposed ML approach integrates physics-based orbit prediction algorithms with a learning-based process that focuses on reducing the prediction errors. Using a simulation-based space catalog environment as the test bed, the paper demonstrates three types of generalization capability for the proposed ML approach: (1) the ML model can be used to improve the same RSO's orbit information that is not available during the learning process but shares the same time interval as the training data; (2) the ML model can be used to improve predictions of the same RSO at future epochs; and (3) the ML model based on a RSO can be applied to other RSOs that share some common features.
A modern elaboration of the Ramified Theory of Types
Laan, T.D.L.; Nederpelt, R.P.
1996-01-01
The paper first formalizes the ramified type theory as (informally) described in the Principia Mathematica [32]. This formalization is close to the ideas of the Principia, but also meets contemporary requirements on formality and accuracy, and therefore is a new supply to the known literature on the
Accuracy of megavolt radiation dosimetry using thermoluminescent lithium fluoride.
Rudén, B I; Bengtsson, L G
1977-04-01
The relative light output per Gy in polystyrene for roentgen beams of 6 and 42 MV and electrons between 2.2 and 34.5 MeV relative to 60Co gamma radiation is reported for different kinds of LiF dosemeters. The distribution of the absorbed dose inside a 0.25 and 0.4 mm thick LiF-teflon disc surrounded by polystyrene and irradiated with 60Co, 42 MV roentgen radiation and 39 MeV electrons was measured using 0.01 and 0.02 mm thick Lif-teflon discs. The measurements show that the absorbed dose distribution in the dosemeter depends on the energy of the radiation. When flat dosemeters were used, differences between the signals measured at the two orientations possible during read-out could easily amount to several per cent, and for this reason 0.4 mm and 0.5 mm LiF-Teflon discs were not trusted when the highest accuracy was required. The cavity theory by Burlin does not account for the phenomena caused by differences in electron scattering properties of the dosemeter and the phantom material. Some suggestions are presented for a different cavity theory for flat dosemeters dealing also with these phenomena. It describes the results to about the same degree of approximation as the Burlin theory, and fails to explain the observed energy dependence for electrons.
International Nuclear Information System (INIS)
Vajskopf, V.F.
1982-01-01
The article deals with the history of the development of quantum electrodynamics since the date of publishing the work by P.A.M. Dirac ''The Quantum Theory of the Emission and Absorption of Radiation''. Classic ''before-Dirac'' electrodynamics related with the names of Maxwell, Lorenz, Hertz, is outlined. Work of Bohr and Rosenfeld is shown to clarify the physical sense of quantized field and to reveal the existence of uncertainties between the strengths of different fields. The article points to the significance of the article ''Quantum theory of radiation'' by E. Fermi which clearly describes the Dirac theory of radiation, relativistic wave equation and fundamentals of quantum electrodynamics. Shown is work on elimination of troubles related with the existence of states with negative kinetic energy or with negative mass. Hypothesis on the Dirac filled-in vacuum led to understanding of the existence of antiparticles and two unknown till then fundamental processes - pair production and annihilation. Ways of fighting against the infinite quantities in quantum electrodynamics are considered. Renormalization of the theory overcame all the infinities and gave a pattern for calculation of any processes of electron interactions with electromagnetic field to any desired accuracy
Jou, Jerwen
2008-01-01
Recall latency, recall accuracy rate, and recall confidence were examined in free recall as a function of recall output serial position using a modified Deese-Roediger-McDermott paradigm to test a strength-based theory against the dual-retrieval process theory of recall output sequence. The strength theory predicts the item output sequence to be…
Scullin, Matthew H.; Bonner, Karri
2006-01-01
The current study examined the relations among 3- to 5-year-olds' theory of mind, inhibitory control, and three measures of suggestibility: yielding to suggestive questions (yield), shifting answers in response to negative feedback (shift), and accuracy in response to misleading questions during a pressured interview about a live event. Theory of…
Kandel, Daniel; Levinski, Vladimir; Sapiens, Noam; Cohen, Guy; Amit, Eran; Klein, Dana; Vakshtein, Irina
2012-03-01
Currently, the performance of overlay metrology is evaluated mainly based on random error contributions such as precision and TIS variability. With the expected shrinkage of the overlay metrology budget to DBO (1st order diffraction based overlay). It is demonstrated that the sensitivity of DBO to overlay mark asymmetry is larger than the sensitivity of imaging overlay. Finally, we show that a recently developed measurement quality metric serves as a valuable tool for improving overlay metrology accuracy. Simulation results demonstrate that the accuracy of imaging overlay can be improved significantly by recipe setup optimized using the quality metric. We conclude that imaging overlay metrology, complemented by appropriate use of measurement quality metric, results in optimal overlay accuracy.
Simulations of pulsating one-dimensional detonations with true fifth order accuracy
International Nuclear Information System (INIS)
Henrick, Andrew K.; Aslam, Tariq D.; Powers, Joseph M.
2006-01-01
A novel, highly accurate numerical scheme based on shock-fitting coupled with fifth order spatial and temporal discretizations is applied to a classical unsteady detonation problem to generate solutions with unprecedented accuracy. The one-dimensional reactive Euler equations for a calorically perfect mixture of ideal gases whose reaction is described by single-step irreversible Arrhenius kinetics are solved in a series of calculations in which the activation energy is varied. In contrast with nearly all known simulations of this problem, which converge at a rate no greater than first order as the spatial and temporal grid is refined, the present method is shown to converge at a rate consistent with the fifth order accuracy of the spatial and temporal discretization schemes. This high accuracy enables more precise verification of known results and prediction of heretofore unknown phenomena. To five significant figures, the scheme faithfully recovers the stability boundary, growth rates, and wave-numbers predicted by an independent linear stability theory in the stable and weakly unstable regime. As the activation energy is increased, a series of period-doubling events are predicted, and the system undergoes a transition to chaos. Consistent with general theories of non-linear dynamics, the bifurcation points are seen to converge at a rate for which the Feigenbaum constant is 4.66 ± 0.09, in close agreement with the true value of 4.669201... As activation energy is increased further, domains are identified in which the system undergoes a transition from a chaotic state back to one whose limit cycles are characterized by a small number of non-linear oscillatory modes. This result is consistent with behavior of other non-linear dynamical systems, but not typically considered in detonation dynamics. The period and average detonation velocity are calculated for a variety of asymptotically stable limit cycles. The average velocity for such pulsating detonations is found
Energy Technology Data Exchange (ETDEWEB)
Grojean, Ch
1999-05-04
The Glashow-Salam-Weinberg theory describing electroweak interactions is one of the best successes of quantum field theory; it has passed all the experimental tests of particles physics with a high accuracy. However, this theory suffers from some deficiencies in the sense that some parameters, especially those involved in the generation of the mass of the elementary particles, are fixed to unnatural values. Moreover gravitation whose quantization cannot be achieved in ordinary quantum filed theory is hot taken into account. The aim of this PhD dissertation is to study some theories beyond the Standard Model and inspired by superstring theories. My endeavour has been to develop theoretical aspects of an effective dynamical description of one of the soltonic states of the strongly coupled strings. An important part of my results is also devoted to a more phenomenological analysis of the low energy effects of the symmetries that assure the coherence of the theories at high energy: these symmetries could explain the fermion mass hierarchy and could be directly observable in collider experiments. It is also shown how the geometrical properties of compactified spaces characterize the vacuum of string theory in a non-perturbative regime; such a vacuum can be used to construct a unified theory of gauge and gravitational interactions with a supersymmetry softy broken at a TcV scale. (author)
Transport Theory for Propagation and Reverberation
2016-07-20
develop evolution equations for the moments (or averages) of the field, and it has been applied to diverse topics quite separate from acoustics. Our...comparisons with TREX13 results, validations studies of transport theory accuracy using comparisons with parabolic equation (PE) results will be summarized...swale structure in the region of the experiment site. The spikes are likely the result of scattering from inclusions , such as clumps of sand or shell
Directory of Open Access Journals (Sweden)
Bruno Silva Cota
2017-12-01
Full Text Available Resumo Este projeto trata da validação de um sistema recém desenvolvido para a soldagem pelo processo friction stir welding, que foi adaptado a um robô antropomórfico com capacidade de 500 kg e seis graus de liberdade. Para garantir que o sistema projetado é capaz de soldar materiais pelo processo FSW, ou seja, garantir que possui rigidez, resistência e torque suficientes para realizar a operação de soldagem, faz-se necessário realizar a validação do mesmo. Para tanto, foi necessário soldar um material conhecido, com parâmetros já estabelecidos, e utilizar uma ferramenta apropriadamente dimensionada. Dessa forma, escolheu-se a liga 5052 H43 de 3 mm de espessura, usada na produção de navios, embarcações e estruturas automotivas. Para a soldagem das juntas finais foi usada uma ferramenta fabricada em AISI H13, com pino cônico liso e diâmetro do ombro de 18 mm. A velocidade rotacional da ferramenta foi mantida constante em 378 rpm, e a velocidade de avanço em 7,5 mm/min, sendo a inclinação da ferramenta de 2°. Verificou-se após os ensaios que o sistema de soldagem projetado se mostrou eficaz em aplicações de soldagem FSW, apresentando torque e resistência mecânica suficientes para a união de materiais com baixo ponto de fusão. Por meio dos parâmetros utilizados, bem como da geometria da ferramenta, foi possível obter juntas da liga de alumínio 5052 H34 soldadas com: bom aspecto superficial, baixos valores de rebarba, ausência de sulcos ou vazios ao longo da linha de soldagem e com penetração total.
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Elizabeth Bernardino
2010-06-01
Full Text Available Este artigo objetiva identificar a demanda e as possibilidades de atuação da enfermeira de ligação no Hospital de Clínicas da Universidade Federal do Paraná. É uma pesquisa descritiva na modalidade estudo de caso, desenvolvida de agosto de 2007 a maio de 2008 e realizada em duas etapas distintas. Primeiramente se realizou uma monitorização das altas hospitalares por meio de formulários, e em seguida, após a seleção de uma unidade de internação em que houve a atuação do papel de enfermeira de ligação junto aos usuários com alta hospitalar, foram entrevistados 10 destes, com a utilização de um roteiro semi-estruturado. Por último, foi realizada a categorização das entrevistas e submissão dos dados à análise temática. Os resultados apontam que a implantação da função enfermeira de ligação é um passo para viabilizar a integração do HC/UFPR à rede e colaborar para a integralidade da atenção.Este artículo tiene como objetivo identificar la demanda y posibilidades de acción de la enfermera de comunicación en el Hospital de Clínicas de la Universidad Federal de Paraná. Es un trabajo descriptivo en la modalidad estudio de caso, desarrollado entre agosto de 2007 y mayo de 2008, y realizado en dos etapas. Primero, se realizó un seguimiento de altas hospitalarias por medio de formularios; posteriormente fue seleccionada una unidad de internación en que hubo la acción de la Enfermera de Comunicación junto a los pacientes de alta hospitalaria y fueron realizadas entrevistas semi-estructuradas con 10 destos. Finalmente, fue realizada la categorización y envío de datos para análisis temática. Los resultados demostraron que la implantación de la función Enfermera de Comunicación es un paso para viabilizar la integración del HC/UFPR a la red y colaborar para la integralidad de la atención.This paper aims to identify the demand and potential activities of the Liaison Nurse position in the Hospital de Cl
Automatic J–A Model Parameter Tuning Algorithm for High Accuracy Inrush Current Simulation
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Xishan Wen
2017-04-01
Full Text Available Inrush current simulation plays an important role in many tasks of the power system, such as power transformer protection. However, the accuracy of the inrush current simulation can hardly be ensured. In this paper, a Jiles–Atherton (J–A theory based model is proposed to simulate the inrush current of power transformers. The characteristics of the inrush current curve are analyzed and results show that the entire inrush current curve can be well featured by the crest value of the first two cycles. With comprehensive consideration of both of the features of the inrush current curve and the J–A parameters, an automatic J–A parameter estimation algorithm is proposed. The proposed algorithm can obtain more reasonable J–A parameters, which improve the accuracy of simulation. Experimental results have verified the efficiency of the proposed algorithm.
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E. P. Avés
2008-12-01
Full Text Available O recobrimento de ligas metálicas com cerâmicas bioativas visa acelerar a formação óssea ao redor do implante, contribuindo para a sua estabilização. Neste trabalho estudou-se a fase cerâmica de hidroxiapatita depositada pelo processo sol-gel em chapas da liga metálica Ti-6Al-4V. A camada de recobrimento foi caracterizada por microscopia eletrônica de varredura, por difração de raios X e sua adesão ao substrato foi avaliada pelo teste de cisalhamento O teste de citocompatibilidade mostrou que o processo de recobrimento por sol-gel não promoveu morte celular significativamente maior que o controle (p > 0,05. Além disso, hastes femorais removidas de pacientes (explantes foram adequadamente recobertas utilizando-se o processo sol-gel.The coating of metallic alloys with bioactive ceramics aims to accelerate bone formation around the implant, contributing to its fixation. In this paper, the deposition of hydroxyapatite ceramic on Ti-6Al-4V alloy sheets by the sol-gel method was studied. The coating layer was characterized by scanning electron microscopy, X-ray diffraction and its adhesion to substrate was evaluated by shear testing. The citocompatibility test shows that the sol-gel coating did not provoke the cell death significantly higher than the control (p > 0.05. Moreover, femoral stems removed from patient (explants were adequately coated using the sol-gel process.
International Nuclear Information System (INIS)
Lin, H.C.; Hsieh, B.J.; Valentin, R.A.
1981-01-01
The endochronic theory of plasticity proposed by Valanis has been applied in predicting the inelastic responses of structural systems. A recently developed convected coordinates finite-element program has been modified to use an endochronic constitutive law. A series of sample problems for a variety of dynamic loadings are presented. The calculations that have been performed comparing classical and endochronic plasticity theories have revealed that the endochronic approach can result in a substantial reduction in computer time for equivalent solution accuracy. This result, combined with the apparent accuracy of material representation indicate that the use of endochronic plasticity has great potential in evaluating the dynamic response of structural systems. (orig.)
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Joaquín Lago Ballesteros
2009-01-01
Full Text Available Resumen Existe una considerable variación en el número de partidos disputados por los equipos de fútbol durante una temporada. Los mejores equipos juegan varios partidos a la semana tanto en las competiciones domesticas como en la Liga de Campeones. Se ha especulado que un período cargado de partidos puede limitar el rendimiento de los conjuntos. En este trabajo se estudia el efecto que tiene para un equipo disputar un partido de la Liga de Campeones sobre el resultado alcanzado en el encuentro de la Liga Española en el fin de semana anterior. La muestra consiste en 374 partidos de la Liga Española jugados por los equipos que se encontraban simultáneamente disputando la Liga de Campeones entre las temporadas 2003-2004 y 2006- 2007. Los resultados alcanzados mediante un modelo logit multinomial permiten demostrar que disputar un partido de la Liga de Campeones no reduce la probabilidad de ganar en el partido de la Liga Española. Además se ha verificado que la probabilidad de ganar en el partido del fin de semana de la Liga Española es mayor cuando el partido de la Liga de Campeones a disputar pertenece a la fase de liguilla respecto a si se corresponde con el formato de eliminación directa.Palabras clave: fútbol; liga española; liga de campeones; logit multinomial; densidad competitive. Abstract There is a considerable variation in the number of matches played per season by clubs in the Spanish Soccer. The successful top clubs play several matches a week in domestic leagues as well as in the UEFA Champions League. It has been speculated that a period full of matches can lead to player fatigue which may result in underperformance. Using data from 374 matches of the Spanish Soccer League played from the 2003-04 to the 2006-07 seasons and according to the estimation based on logit multinomial this study shows that Spanish Champions League teams did not perform below their normal standard at the weekend when they played a Champions
Last stop on the road to repair: structure of E. coli DNA ligase bound to nicked DNA-adenylate.
Nandakumar, Jayakrishnan; Nair, Pravin A; Shuman, Stewart
2007-04-27
NAD(+)-dependent DNA ligases (LigA) are ubiquitous in bacteria and essential for growth. Their distinctive substrate specificity and domain organization vis-a-vis human ATP-dependent ligases make them outstanding targets for anti-infective drug discovery. We report here the 2.3 A crystal structure of Escherichia coli LigA bound to an adenylylated nick, which captures LigA in a state poised for strand closure and reveals the basis for nick recognition. LigA envelopes the DNA within a protein clamp. Large protein domain movements and remodeling of the active site orchestrate progression through the three chemical steps of the ligation reaction. The structure inspires a strategy for inhibitor design.
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Francisco J Valverde-Albacete
Full Text Available The most widely spread measure of performance, accuracy, suffers from a paradox: predictive models with a given level of accuracy may have greater predictive power than models with higher accuracy. Despite optimizing classification error rate, high accuracy models may fail to capture crucial information transfer in the classification task. We present evidence of this behavior by means of a combinatorial analysis where every possible contingency matrix of 2, 3 and 4 classes classifiers are depicted on the entropy triangle, a more reliable information-theoretic tool for classification assessment. Motivated by this, we develop from first principles a measure of classification performance that takes into consideration the information learned by classifiers. We are then able to obtain the entropy-modulated accuracy (EMA, a pessimistic estimate of the expected accuracy with the influence of the input distribution factored out, and the normalized information transfer factor (NIT, a measure of how efficient is the transmission of information from the input to the output set of classes. The EMA is a more natural measure of classification performance than accuracy when the heuristic to maximize is the transfer of information through the classifier instead of classification error count. The NIT factor measures the effectiveness of the learning process in classifiers and also makes it harder for them to "cheat" using techniques like specialization, while also promoting the interpretability of results. Their use is demonstrated in a mind reading task competition that aims at decoding the identity of a video stimulus based on magnetoencephalography recordings. We show how the EMA and the NIT factor reject rankings based in accuracy, choosing more meaningful and interpretable classifiers.
Diagnosing Eyewitness Accuracy
Russ, Andrew
2015-01-01
Eyewitnesses frequently mistake innocent people for the perpetrator of an observed crime. Such misidentifications have led to the wrongful convictions of many people. Despite this, no reliable method yet exists to determine eyewitness accuracy. This thesis explored two new experimental methods for this purpose. Chapter 2 investigated whether repetition priming can measure prior exposure to a target and compared this with observers’ explicit eyewitness accuracy. Across three experiments slower...
On the accuracy and reliability of predictions by control-system theory.
Bourbon, W T; Copeland, K E; Dyer, V R; Harman, W K; Mosley, B L
1990-12-01
In three experiments we used control-system theory (CST) to predict the results of tracking tasks on which people held a handle to keep a cursor even with a target on a computer screen. 10 people completed a total of 104 replications of the task. In each experiment, there were two conditions: in one, only the handle affected the position of the cursor; in the other, a random disturbance also affected the cursor. From a person's performance during Condition 1, we derived constants used in the CST model to predict the results of Condition 2. In two experiments, predictions occurred a few minutes before Condition 2; in one experiment, the delay was 1 yr. During a 1-min. experimental run, the positions of handle and cursor, produced by the person, were each sampled 1800 times, once every 1/30 sec. During a modeling run, the model predicted the positions of the handle and target for each of the 1800 intervals sampled in the experimental run. In 104 replications, the mean correlation between predicted and actual positions of the handle was .996; SD = .002.
Fundamental theories of waves and particles formulated without classical mass
Fry, J. L.; Musielak, Z. E.
2010-12-01
Quantum and classical mechanics are two conceptually and mathematically different theories of physics, and yet they do use the same concept of classical mass that was originally introduced by Newton in his formulation of the laws of dynamics. In this paper, physical consequences of using the classical mass by both theories are explored, and a novel approach that allows formulating fundamental (Galilean invariant) theories of waves and particles without formally introducing the classical mass is presented. In this new formulation, the theories depend only on one common parameter called 'wave mass', which is deduced from experiments for selected elementary particles and for the classical mass of one kilogram. It is shown that quantum theory with the wave mass is independent of the Planck constant and that higher accuracy of performing calculations can be attained by such theory. Natural units in connection with the presented approach are also discussed and justification beyond dimensional analysis is given for the particular choice of such units.
International Nuclear Information System (INIS)
Kazama, Y.; Yao, Y.
1982-01-01
In spontaneously broken non-Abelian gauge theories which admit gauge hierarchy at the tree level, we show, to all orders in perturbation theory, that (i) the superheavy particles decouple from the light sector at low energies, (ii) an effective low-energy renormalizable theory emerges together with appropriate counterterms, and (iii) the gauge hierarchy can be consistently maintained in the presence of radiative corrections. These assertions are explicitly demonstrated for O(3) gauge theory with two triplets of Higgs particles in a manner easily applicable to more realistic grand unified theories. Furthermore, as a by-product of our analysis, we obtain a systematic method of computing the parameters of the effective low-energy theory via renormalization-group equations to any desired accuracy
Trait Perception Accuracy and Acquaintance Within Groups: Tracking Accuracy Development.
Brown, Jill A; Bernieri, Frank
2017-05-01
Previous work on trait perception has evaluated accuracy at discrete stages of relationships (e.g., strangers, best friends). A relatively limited body of literature has investigated changes in accuracy as acquaintance within a dyad or group increases. Small groups of initially unacquainted individuals spent more than 30 hr participating in a wide range of activities designed to represent common interpersonal contexts (e.g., eating, traveling). We calculated how accurately each participant judged others in their group on the big five traits across three distinct points within the acquaintance process: zero acquaintance, after a getting-to-know-you conversation, and after 10 weeks of interaction and activity. Judgments of all five traits exhibited accuracy above chance levels after 10 weeks. An examination of the trait rating stability revealed that much of the revision in judgments occurred not over the course of the 10-week relationship as suspected, but between zero acquaintance and the getting-to-know-you conversation.
Study on Parameter Identification of Assembly Robot based on Screw Theory
Yun, Shi; Xiaodong, Zhang
2017-11-01
The kinematic model of assembly robot is one of the most important factors affecting repetitive precision. In order to improve the accuracy of model positioning, this paper first establishes the exponential product model of ER16-1600 assembly robot on the basis of screw theory, and then based on iterative least squares method, using ER16-1600 model robot parameter identification. By comparing the experiment before and after the calibration, it is proved that the method has obvious improvement on the positioning accuracy of the assembly robot.
Symmetries and symmetry breaking beyond the electroweak theory
International Nuclear Information System (INIS)
Grojean, Ch.
1999-01-01
The Glashow-Salam-Weinberg theory describing electroweak interactions is one of the best successes of quantum field theory; it has passed all the experimental tests of particles physics with a high accuracy. However, this theory suffers from some deficiencies in the sense that some parameters, especially those involved in the generation of the mass of the elementary particles, are fixed to unnatural values. Moreover gravitation whose quantization cannot be achieved in ordinary quantum filed theory is hot taken into account. The aim of this PhD dissertation is to study some theories beyond the Standard Model and inspired by superstring theories. My endeavour has been to develop theoretical aspects of an effective dynamical description of one of the soltonic states of the strongly coupled strings. An important part of my results is also devoted to a more phenomenological analysis of the low energy effects of the symmetries that assure the coherence of the theories at high energy: these symmetries could explain the fermion mass hierarchy and could be directly observable in collider experiments. It is also shown how the geometrical properties of compactified spaces characterize the vacuum of string theory in a non-perturbative regime; such a vacuum can be used to construct a unified theory of gauge and gravitational interactions with a supersymmetry softy broken at a TcV scale. (author)
International Nuclear Information System (INIS)
Arbuzov, B.A.; D'yakonov, V.Yu.; Rochev, V.E.
1975-01-01
Solution of equations for imaginary part of forward scattering amplitude in ladder approximation for theories with lambdaphisup(n),n(>=)4 interaction have been obtained. Two types of diagrams have been considered for lambdaphisup(n) renormalizable theory. It is shown, that the leading singularity is the branch point, which gives the power asymptotics with accuracy up to logarithms. The unrenormalizable theory with n(>=)5 lead to exponentially rising asymptotics
Directory of Open Access Journals (Sweden)
Joe Manganelli
2016-10-01
Full Text Available This paper presents reflections on integrating theory, craft, research, and practice to improve the accuracy and resiliency of each. The reflections build toward a set of statements about the value and the cost of integrating theory, craft, research, and practice. Specifically, the authors offer the Privileged Work / Non-Privileged Work Framework and concept of cultivating Perspectival Acuity.
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Braulio Sánchez Ureña
2011-12-01
Full Text Available El propósito de este estudio fue analizar y contrastar el perfil de rendimiento técnico del equipo tetracampeón de la Liga Superior de Baloncesto de Costa Rica. Se registró 142 juegos a lo largo de las temporadas 2007, 2008 y 2009. Los indicadores de rendimiento escogido fueron: lanzamientos de dos y tres puntos (convertidos, fallados, porcentaje de efectividad, lanzamientos de tiro libre (convertidos, fallados, porcentaje de efectividad, puntos, rebotes defensivos y ofensivos, faltas, pérdidas de balón, asistencias y robos de balón. La descripción de la información se basó en valores de frecuencia absoluta y relativa. El contraste de datos por temporada y periodo de juego se hizo con base en las técnicas no paramétricas U-test, test de Friedman y el Chi 2. En todos los casos se utilizó el SPSS versión 15.0 con un nivel de significancia de p ≤ 0,05. Los resultados mostraron un mejor perfil de rendimiento técnico en la temporada 2008, caracterizándose por mejores porcentajes en tiros de 2, tiros libres, menor número de pérdidas de balón y mayor cantidad de robos del balón y asistencias. En relación con el periodo de juego, el equipo mostró un mejor perfil de rendimiento técnico durante los segundos tiempos del partido. En general, el porcentaje de efectividad de tiros de 2 y tiros libres estuvo arriba del 60 % en ambos periodos de juego, mientras que el porcentaje de tiros de 3 osciló entre el 26.4 % y el 29.2 %. En conclusión, el equipo mostró un perfil de rendimiento técnico similar al reportado en la literatura y deja clara evidencia de la importancia que tiene el registro y seguimiento de los indicadores de rendimiento técnico en el baloncesto.
Paul Weindling
2006-01-01
A Organização de Saúde da Liga das Nações colaborou com especialistas latino-americanos em saúde pública e doenças infecciosas desde o início da década de 1920 e até a eclosão da Segunda Guerra Mundial. Desenvolveu estudos sobre saúde e nutrição infantil e sobre a lepra. A abordagem foi orientada por especialistas, tendo em mira o desenvolvimento da saúde pública em bases científicas. Houve conferências, visitas e relatórios sobre a América Latina. O artigo demonstra que a colaboração da Amér...
Efeitos corrosivos encontrados em materiais magnéticos empregados em ortodontia
Itabaiana Sobrinho, Sisenando
2006-01-01
O emprego de ligas magnéticas permitiu a criação de novas opções em terapias odontológicas, especialmente na Ortodontia, onde a sua utilização já é bastante difundida. A inovação no emprego dos magnetos veio com a introdução de novas ligas magnéticas à base dos elementos terras raras pertencentes à família dos lantanídeos, como as ligas de samário-cobalto (SmCo5) e neodímio-ferro-boro (Nd2Fe14B). Magnetos fabricados com as ligas acima são 20 vezes mais fortes que os magnetos de alumínio-níque...
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Cláudia Vianna Maurer-Morelli
2007-03-01
Full Text Available Voltage-gated potassium channels (VGKCs play a critical role in the regulation of neuronal excitability and have been implicated in some types of epilepsies. Recently, autoimmune limbic encephalitis (LE was associated with antibodies against VGKC. In addition, patients with LE showed partial epilepsy and increased T2 signal abnormalities in limbic structures. We have reported familial mesial temporal lobe epilepsy (FMTLE associated with hippocampal atrophy (HA and other signs of mesial temporal sclerosis detected by magnetic resonance imaging (MRI. In order to investigate whether VGKC may be associated to HA present in FMTLE, we perform linkage study in these candidate genes. Seventy-three microsatellites markers were genotyped in different human autosomal chromosome. Two-point LOD scores did not show evidence for linkage with any of the microsatellite markers genotyped (Zmax ranging from 0.11to-9.53 at theta=0.00. In the present study, linkage data showed no evidence that VGKC are involved in the determination of HA in FMTLE.Canais de potássio voltagem-dependentes (CPVD desempenham importante papel na excitabilidade neuronal e estão associados a determinados tipos de epilepsia. Recentemente, um tipo de encefalite límbica autoimune (EL foi associado com anticorpos contra CPVD. Além disso, há relatos de pacientes com EL e epilepsia parcial, além de hipersinal em regiões límbicas detectadas em imagens de ressonância magnética (IRM. Nós temos descrito a epilepsia de lobo temporal mesial familial (ELTMF associada à atrofia hipocampal (AH e outros sinais de esclerose mesial temporal observadas em IRM. Para investigar se os CPVD podem estar associados com a AH identificada na ELTMF, empregamos o estudo de ligação genética nesses genes candidatos. Setenta e três marcadores microssatélites foram genotipados e o LOD score de dois pontos mostrou Zmax variando de 0.11 a -9.53 para teta=0.00. No presente estudo, os dados obtidos com a an
Potential-functional embedding theory for molecules and materials.
Huang, Chen; Carter, Emily A
2011-11-21
We introduce a potential-functional embedding theory by reformulating a recently proposed density-based embedding theory in terms of functionals of the embedding potential. This potential-functional based theory completes the dual problem in the context of embedding theory for which density-functional embedding theory has existed for two decades. With this potential-functional formalism, it is straightforward to solve for the unique embedding potential shared by all subsystems. We consider charge transfer between subsystems and discuss how to treat fractional numbers of electrons in subsystems. We show that one is able to employ different energy functionals for different subsystems in order to treat different regions with theories of different levels of accuracy, if desired. The embedding potential is solved for by directly minimizing the total energy functional, and we discuss how to efficiently calculate the gradient of the total energy functional with respect to the embedding potential. Forces are also derived, thereby making it possible to optimize structures and account for nuclear dynamics. We also extend the theory to spin-polarized cases. Numerical examples of the theory are given for some homo- and hetero-nuclear diatomic molecules and a more complicated test of a six-hydrogen-atom chain. We also test our theory in a periodic bulk environment with calculations of basic properties of bulk NaCl, by treating each atom as a subsystem. Finally, we demonstrate the theory for water adsorption on the MgO(001)surface.
Social Power Increases Interoceptive Accuracy
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Mehrad Moeini-Jazani
2017-08-01
Full Text Available Building on recent psychological research showing that power increases self-focused attention, we propose that having power increases accuracy in perception of bodily signals, a phenomenon known as interoceptive accuracy. Consistent with our proposition, participants in a high-power experimental condition outperformed those in the control and low-power conditions in the Schandry heartbeat-detection task. We demonstrate that the effect of power on interoceptive accuracy is not explained by participants’ physiological arousal, affective state, or general intention for accuracy. Rather, consistent with our reasoning that experiencing power shifts attentional resources inward, we show that the effect of power on interoceptive accuracy is dependent on individuals’ chronic tendency to focus on their internal sensations. Moreover, we demonstrate that individuals’ chronic sense of power also predicts interoceptive accuracy similar to, and independent of, how their situationally induced feeling of power does. We therefore provide further support on the relation between power and enhanced perception of bodily signals. Our findings offer a novel perspective–a psychophysiological account–on how power might affect judgments and behavior. We highlight and discuss some of these intriguing possibilities for future research.
PADÉ APPROXIMANTS FOR THE EQUATION OF STATE FOR RELATIVISTIC HYDRODYNAMICS BY KINETIC THEORY
Energy Technology Data Exchange (ETDEWEB)
Tsai, Shang-Hsi; Yang, Jaw-Yen, E-mail: shanghsi@gmail.com [Institute of Applied Mechanics, National Taiwan University, Taipei 10764, Taiwan (China)
2015-07-20
A two-point Padé approximant (TPPA) algorithm is developed for the equation of state (EOS) for relativistic hydrodynamic systems, which are described by the classical Maxwell–Boltzmann statistics and the semiclassical Fermi–Dirac statistics with complete degeneracy. The underlying rational function is determined by the ratios of the macroscopic state variables with various orders of accuracy taken at the extreme relativistic limits. The nonunique TPPAs are validated by Taub's inequality for the consistency of the kinetic theory and the special theory of relativity. The proposed TPPA is utilized in deriving the EOS of the dilute gas and in calculating the specific heat capacity, the adiabatic index function, and the isentropic sound speed of the ideal gas. Some general guidelines are provided for the application of an arbitrary accuracy requirement. The superiority of the proposed TPPA is manifested in manipulating the constituent polynomials of the approximants, which avoids the arithmetic complexity of struggling with the modified Bessel functions and the hyperbolic trigonometric functions arising from the relativistic kinetic theory.
Rare Decays Probing Physics Beyond the Standard Theory
Teubert, Frederic
2016-01-01
In the last 50 years we have seen how an initially ad-hoc and not widely accepted theory of the strong and electroweak interactions (Standard Theory: ST) has correctly predicted the entire accelerator based experimental observations with incredible accuracy (with the important exception of neutrino oscillation experiments). Decays of the ST particles (quarks and leptons), which are rare due to some symmetry of the theory, have played an important role in the formalism of the ST. These rare decays have been powerful tools to search for new particle interactions with the ST particles, which may not necessarily have the same symmetries. In this article, I will describe the indirect search for evidence of new physics (NP) using quark and lepton flavour changing neutral decays, which are highly suppressed within the ST, and constitute strong probes of potential new flavour structures.
Modified Hermitian treatment of Dyson boson expansion theory
International Nuclear Information System (INIS)
Kajiyama, Atsushi
2009-01-01
The Hermitian treatment of the Dyson-type boson expansion theory is reinvestigated with the aid of small-parameter expansion. A naive application of the Hermitization formula sometimes yields an unrealistic phase that spoils the conventional treatment. The complementary use of another formula having the form of the arithmetic mean can avoid that problem. This modification will improve the accuracy of the Hermitian treatment. (author)
An adaptive orienting theory of error processing.
Wessel, Jan R
2018-03-01
The ability to detect and correct action errors is paramount to safe and efficient goal-directed behaviors. Existing work on the neural underpinnings of error processing and post-error behavioral adaptations has led to the development of several mechanistic theories of error processing. These theories can be roughly grouped into adaptive and maladaptive theories. While adaptive theories propose that errors trigger a cascade of processes that will result in improved behavior after error commission, maladaptive theories hold that error commission momentarily impairs behavior. Neither group of theories can account for all available data, as different empirical studies find both impaired and improved post-error behavior. This article attempts a synthesis between the predictions made by prominent adaptive and maladaptive theories. Specifically, it is proposed that errors invoke a nonspecific cascade of processing that will rapidly interrupt and inhibit ongoing behavior and cognition, as well as orient attention toward the source of the error. It is proposed that this cascade follows all unexpected action outcomes, not just errors. In the case of errors, this cascade is followed by error-specific, controlled processing, which is specifically aimed at (re)tuning the existing task set. This theory combines existing predictions from maladaptive orienting and bottleneck theories with specific neural mechanisms from the wider field of cognitive control, including from error-specific theories of adaptive post-error processing. The article aims to describe the proposed framework and its implications for post-error slowing and post-error accuracy, propose mechanistic neural circuitry for post-error processing, and derive specific hypotheses for future empirical investigations. © 2017 Society for Psychophysiological Research.
Systematic review of discharge coding accuracy
Burns, E.M.; Rigby, E.; Mamidanna, R.; Bottle, A.; Aylin, P.; Ziprin, P.; Faiz, O.D.
2012-01-01
Introduction Routinely collected data sets are increasingly used for research, financial reimbursement and health service planning. High quality data are necessary for reliable analysis. This study aims to assess the published accuracy of routinely collected data sets in Great Britain. Methods Systematic searches of the EMBASE, PUBMED, OVID and Cochrane databases were performed from 1989 to present using defined search terms. Included studies were those that compared routinely collected data sets with case or operative note review and those that compared routinely collected data with clinical registries. Results Thirty-two studies were included. Twenty-five studies compared routinely collected data with case or operation notes. Seven studies compared routinely collected data with clinical registries. The overall median accuracy (routinely collected data sets versus case notes) was 83.2% (IQR: 67.3–92.1%). The median diagnostic accuracy was 80.3% (IQR: 63.3–94.1%) with a median procedure accuracy of 84.2% (IQR: 68.7–88.7%). There was considerable variation in accuracy rates between studies (50.5–97.8%). Since the 2002 introduction of Payment by Results, accuracy has improved in some respects, for example primary diagnoses accuracy has improved from 73.8% (IQR: 59.3–92.1%) to 96.0% (IQR: 89.3–96.3), P= 0.020. Conclusion Accuracy rates are improving. Current levels of reported accuracy suggest that routinely collected data are sufficiently robust to support their use for research and managerial decision-making. PMID:21795302
International Nuclear Information System (INIS)
Mohr, J.; Ehrfeld, W.; Muenchmeyer, D.
1988-07-01
Under the LIGA process plastic microstructures with extraordinarily high aspect ratios are produced by means of deep-etch synchrotron radiation lithography. These microstructures are used as templates for the fabrication by electroforming of metallic microstructures. The several hundred micrometer thick resist layers required in the process are polymerized directly on a metal base plate using a methacrylate based resin. This provides sufficient stability during the production process and also a reliable plating base for the electrodeposition of the metal. Perfect adhesion of micron-sized microstructures on a smooth surface can be achieved if the polished metal surface is sputtered with titanium and chemically oxidized afterwards. Alternatively it is also possible to add an internal adhesion promoter like methacryl oxypropyl trimethoxy silane to the resin. By means of this adhesion promoter chemical bonding between the metal surface and the polymer is achieved. (orig.)
Spherical radial basis functions, theory and applications
Hubbert, Simon; Morton, Tanya M
2015-01-01
This book is the first to be devoted to the theory and applications of spherical (radial) basis functions (SBFs), which is rapidly emerging as one of the most promising techniques for solving problems where approximations are needed on the surface of a sphere. The aim of the book is to provide enough theoretical and practical details for the reader to be able to implement the SBF methods to solve real world problems. The authors stress the close connection between the theory of SBFs and that of the more well-known family of radial basis functions (RBFs), which are well-established tools for solving approximation theory problems on more general domains. The unique solvability of the SBF interpolation method for data fitting problems is established and an in-depth investigation of its accuracy is provided. Two chapters are devoted to partial differential equations (PDEs). One deals with the practical implementation of an SBF-based solution to an elliptic PDE and another which describes an SBF approach for solvi...
Variational methods in electron-atom scattering theory
Nesbet, Robert K
1980-01-01
The investigation of scattering phenomena is a major theme of modern physics. A scattered particle provides a dynamical probe of the target system. The practical problem of interest here is the scattering of a low energy electron by an N-electron atom. It has been difficult in this area of study to achieve theoretical results that are even qualitatively correct, yet quantitative accuracy is often needed as an adjunct to experiment. The present book describes a quantitative theoretical method, or class of methods, that has been applied effectively to this problem. Quantum mechanical theory relevant to the scattering of an electron by an N-electron atom, which may gain or lose energy in the process, is summarized in Chapter 1. The variational theory itself is presented in Chapter 2, both as currently used and in forms that may facilitate future applications. The theory of multichannel resonance and threshold effects, which provide a rich structure to observed electron-atom scattering data, is presented in Cha...
The application of Regge calculus to quantum gravity and quantum field theory in a curved background
International Nuclear Information System (INIS)
Warner, N.P.
1982-01-01
The application of Regge calculus to quantum gravity and quantum field theory in a curved background is discussed. A discrete form of exterior differential calculus is developed, and this is used to obtain Laplacians for p-forms on the Regge manifold. To assess the accuracy of these approximations, the eigenvalues of the discrete Laplacians were calculated for the regular tesselations of S 2 and S 3 . The results indicate that the methods obtained in this paper may be used in curved space-times with an accuracy comparing with that obtained in lattice gauge theories on a flat background. It also becomes evident that Regge calculus provides particularly suitable lattices for Monte-Carlo techniques. (author)
Density measurement using gamma radiation - theory and application
International Nuclear Information System (INIS)
Springer, E.K.
1979-01-01
There are still widespread uncertainties about the use and safety of gamma radiation in industries. This paper describes, by the example of radiometric density measurement, the theory of gamma radiation. The differences and advantages of both types of detectors, the ionization chamber and the scintillation counter, are discussed. The degree of accuracy which can be expected from the radiometric density meter will be defined, and the inter-relationship: source strength - measuring range - measuring length(normally the pipe diameter) in relation to the measuring accuracy required will be explained in detail. The use of radioactive material requires the permission of the Atomic Energy Board. The formalities involved to receive a user's licence and the implementations of safety standards set by the local authorities are discussed in depth [af
Thermodynamic perturbation theory for fused hard-sphere and hard-disk chain fluids
International Nuclear Information System (INIS)
Zhou, Y.; Hall, C.K.; Stell, G.
1995-01-01
We find that first-order thermodynamic perturbation theory (TPT1) which incorporates the reference monomer fluid used in the generalized Flory--AB (GF--AB) theory yields an equation of state for fused hard-sphere (FHS) chain fluids that has accuracy comparable to the GF--AB and GF--dimer--AC theories. The new TPT1 equation of state is significantly more accurate than other extensions of the TPT1 theory to FHS chain fluids. The TPT1 is also extended to two-dimensional fused hard-disk chain fluids. For the fused hard-disk dimer fluid, the extended TPT1 equation of state is found to be more accurate than the Boublik hard-disk dimer equation of state. copyright 1995 American Institute of Physics
Data accuracy assessment using enterprise architecture
Närman, Per; Holm, Hannes; Johnson, Pontus; König, Johan; Chenine, Moustafa; Ekstedt, Mathias
2011-02-01
Errors in business processes result in poor data accuracy. This article proposes an architecture analysis method which utilises ArchiMate and the Probabilistic Relational Model formalism to model and analyse data accuracy. Since the resources available for architecture analysis are usually quite scarce, the method advocates interviews as the primary data collection technique. A case study demonstrates that the method yields correct data accuracy estimates and is more resource-efficient than a competing sampling-based data accuracy estimation method.
Vuckovic, Anita; Kwantes, Peter J; Humphreys, Michael; Neal, Andrew
2014-03-01
Signal Detection Theory (SDT; Green & Swets, 1966) is a popular tool for understanding decision making. However, it does not account for the time taken to make a decision, nor why response bias might change over time. Sequential sampling models provide a way of accounting for speed-accuracy trade-offs and response bias shifts. In this study, we test the validity of a sequential sampling model of conflict detection in a simulated air traffic control task by assessing whether two of its key parameters respond to experimental manipulations in a theoretically consistent way. Through experimental instructions, we manipulated participants' response bias and the relative speed or accuracy of their responses. The sequential sampling model was able to replicate the trends in the conflict responses as well as response time across all conditions. Consistent with our predictions, manipulating response bias was associated primarily with changes in the model's Criterion parameter, whereas manipulating speed-accuracy instructions was associated with changes in the Threshold parameter. The success of the model in replicating the human data suggests we can use the parameters of the model to gain an insight into the underlying response bias and speed-accuracy preferences common to dynamic decision-making tasks. © 2013 American Psychological Association
Examining the accuracy of the infinite order sudden approximation using sensitivity analysis
Eno, Larry; Rabitz, Herschel
1981-08-01
A method is developed for assessing the accuracy of scattering observables calculated within the framework of the infinite order sudden (IOS) approximation. In particular, we focus on the energy sudden assumption of the IOS method and our approach involves the determination of the sensitivity of the IOS scattering matrix SIOS with respect to a parameter which reintroduces the internal energy operator ?0 into the IOS Hamiltonian. This procedure is an example of sensitivity analysis of missing model components (?0 in this case) in the reference Hamiltonian. In contrast to simple first-order perturbation theory a finite result is obtained for the effect of ?0 on SIOS. As an illustration, our method of analysis is applied to integral state-to-state cross sections for the scattering of an atom and rigid rotor. Results are generated within the He+H2 system and a comparison is made between IOS and coupled states cross sections and the corresponding IOS sensitivities. It is found that the sensitivity coefficients are very useful indicators of the accuracy of the IOS results. Finally, further developments and applications are discussed.
Kontrola tačnosti rezultata u simulacijama Monte Karlo / Accuracy control in Monte Carlo simulations
Directory of Open Access Journals (Sweden)
Nebojša V. Nikolić
2010-04-01
Full Text Available U radu je demonstrirana primena metode automatizovanog ponavljanja nezavisnih simulacionih eksperimenata sa prikupljanjem statistike slučajnih procesa, u dostizanju i kontroli tačnosti simulacionih rezultata u simulaciji sistema masovnog opsluživanja Monte Karlo. Metoda se zasniva na primeni osnovnih stavova i teorema matematičke statistike i teorije verovatnoće. Tačnost simulacionih rezultata dovedena je u direktnu vezu sa brojem ponavljanja simulacionih eksperimenata. / The paper presents an application of the Automated Independent Replication with Gathering Statistics of the Stochastic Processes Method in achieving and controlling the accuracy of simulation results in the Monte Carlo queuing simulations. The method is based on the application of the basic theorems of the theory of probability and mathematical statistics. The accuracy of the simulation results is linked with a number of independent replications of simulation experiments.
Directory of Open Access Journals (Sweden)
S Hong Lee
Full Text Available Genomic prediction is emerging in a wide range of fields including animal and plant breeding, risk prediction in human precision medicine and forensic. It is desirable to establish a theoretical framework for genomic prediction accuracy when the reference data consists of information sources with varying degrees of relationship to the target individuals. A reference set can contain both close and distant relatives as well as 'unrelated' individuals from the wider population in the genomic prediction. The various sources of information were modeled as different populations with different effective population sizes (Ne. Both the effective number of chromosome segments (Me and Ne are considered to be a function of the data used for prediction. We validate our theory with analyses of simulated as well as real data, and illustrate that the variation in genomic relationships with the target is a predictor of the information content of the reference set. With a similar amount of data available for each source, we show that close relatives can have a substantially larger effect on genomic prediction accuracy than lesser related individuals. We also illustrate that when prediction relies on closer relatives, there is less improvement in prediction accuracy with an increase in training data or marker panel density. We release software that can estimate the expected prediction accuracy and power when combining different reference sources with various degrees of relationship to the target, which is useful when planning genomic prediction (before or after collecting data in animal, plant and human genetics.
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Lorena Soler
2017-12-01
Full Text Available El artículo se propone estudiar las representaciones y los discursos que pusieron en circulación las derechas stronistas en el diario Patria, órgano oficial del Partido Colorado, en el marco del XIIº Congreso de la Liga Anticomunista Mundial (World Anti-Communist League, WACL –realizado en Asunción, en abril de 1979–, analizando el recurso del humor político como artefacto de lucha ideológica. Asumimos que la socialización de las elites políticas locales en una red trasnacional anticomunista supuso diálogos y préstamos para la relaboración, con cierta autonomía, de las identidades de derechas en una coyuntura histórica específica, signada por la Segunda Guerra Fría, el ascenso de Jimmy Carter al gobierno de EE.UU., la crisis interna del régimen stronista y los problemas diplomáticos de Paraguay con ese país por las denuncias de ilícitos y el conocimiento internacional de las violaciones a los derechos humanos. La investigación se apoya en documentos desclasificados, periódicos de la época y en el mencionado Patria.
International Nuclear Information System (INIS)
Jevremovic, Tatjana; Hursin, Mathieu; Satvat, Nader; Hopkins, John; Xiao, Shanjie; Gert, Godfree
2006-01-01
The AGENT (Arbitrary Geometry Neutron Transport) an open-architecture reactor modeling tool is deterministic neutron transport code for two or three-dimensional heterogeneous neutronic design and analysis of the whole reactor cores regardless of geometry types and material configurations. The AGENT neutron transport methodology is applicable to all generations of nuclear power and research reactors. It combines three theories: (1) the theory of R-functions used to generate real three-dimensional whole-cores of square, hexagonal or triangular cross sections, (2) the planar method of characteristics used to solve isotropic neutron transport in non-homogenized 2D) reactor slices, and (3) the one-dimensional diffusion theory used to couple the planar and axial neutron tracks through the transverse leakage and angular mesh-wise flux values. The R-function-geometrical module allows a sequential building of the layers of geometry and automatic sub-meshing based on the network of domain functions. The simplicity of geometry description and selection of parameters for accurate treatment of neutron propagation is achieved through the Boolean algebraic hierarchically organized simple primitives into complex domains (both being represented with corresponding domain functions). The accuracy is comparable to Monte Carlo codes and is obtained by following neutron propagation through real geometrical domains that does not require homogenization or simplifications. The efficiency is maintained through a set of acceleration techniques introduced at all important calculation levels. The flux solution incorporates power iteration with two different acceleration techniques: Coarse Mesh Re-balancing (CMR) and Coarse Mesh Finite Difference (CMFD). The stand-alone originally developed graphical user interface of the AGENT code design environment allows the user to view and verify input data by displaying the geometry and material distribution. The user can also view the output data such
Haberland, A M; König von Borstel, U; Simianer, H; König, S
2012-09-01
Reliable selection criteria are required for young riding horses to increase genetic gain by increasing accuracy of selection and decreasing generation intervals. In this study, selection strategies incorporating genomic breeding values (GEBVs) were evaluated. Relevant stages of selection in sport horse breeding programs were analyzed by applying selection index theory. Results in terms of accuracies of indices (r(TI) ) and relative selection response indicated that information on single nucleotide polymorphism (SNP) genotypes considerably increases the accuracy of breeding values estimated for young horses without own or progeny performance. In a first scenario, the correlation between the breeding value estimated from the SNP genotype and the true breeding value (= accuracy of GEBV) was fixed to a relatively low value of r(mg) = 0.5. For a low heritability trait (h(2) = 0.15), and an index for a young horse based only on information from both parents, additional genomic information doubles r(TI) from 0.27 to 0.54. Including the conventional information source 'own performance' into the before mentioned index, additional SNP information increases r(TI) by 40%. Thus, particularly with regard to traits of low heritability, genomic information can provide a tool for well-founded selection decisions early in life. In a further approach, different sources of breeding values (e.g. GEBV and estimated breeding values (EBVs) from different countries) were combined into an overall index when altering accuracies of EBVs and correlations between traits. In summary, we showed that genomic selection strategies have the potential to contribute to a substantial reduction in generation intervals in horse breeding programs.
Directory of Open Access Journals (Sweden)
Juan Felipe Correa-Mesa
2016-09-01
Full Text Available Introducción. En lucha se presentan eventos que pueden generar alteraciones físicas, como caídas, contactos en el suelo, levantamientos, arqueamientos, entre otros. Objetivo. Estimar la prevalencia de lesiones y factores correlacionados en deportistas practicantes de lucha olímpica. Materiales y métodos. Estudio observacional de tipo correlacional y diseño transversal. Participaron 29 deportistas pertenecientes a la Liga de Bogotá. Resultados. En el último año, 15 deportistas no tuvieron ninguna lesión (51.72%, 11 tuvieron 1 lesión (37.93% y 2 tuvieron 4 lesiones (6.89%. De ellas, el lugar lesionado más prevalente fue el hombro con un 17% y el tipo de lesión más sobresaliente fue la tendinopatía con un 13.79%. El índice de masa corporal (IMC tuvo un efecto positivo en la probabilidad de lesión (valor p=0.07 con significancia al 10% y la variable inicial fue igualmente significativa (valor p=0.014. El resultado del sit and reach test fue significativo al 10% (valor p=0.09, lo que indica una ligera relación positiva entre los más flexibles y la lesión. Conclusiones. La lesión más prevalente ocurrió en el hombro y el tipo de lesión fue la tendinopatía. El IMC, el inicio de la práctica de los 13 a 16 años y el test de sit and seach tienen una significancia positiva hacia el número de lesiones en el último año.
Accurate Ground-State Energies of Solids and Molecules from Time-Dependent Density-Functional Theory
DEFF Research Database (Denmark)
Olsen, Thomas; Thygesen, Kristian Sommer
2014-01-01
We demonstrate that ground-state energies approaching chemical accuracy can be obtained by combining the adiabatic-connection fluctuation-dissipation theorem with time-dependent densityfunctional theory. The key ingredient is a renormalization scheme, which eliminates the divergence...
Algebraic perturbation theory for dense liquids with discrete potentials
Adib, Artur B.
2007-06-01
A simple theory for the leading-order correction g1(r) to the structure of a hard-sphere liquid with discrete (e.g., square-well) potential perturbations is proposed. The theory makes use of a general approximation that effectively eliminates four-particle correlations from g1(r) with good accuracy at high densities. For the particular case of discrete perturbations, the remaining three-particle correlations can be modeled with a simple volume-exclusion argument, resulting in an algebraic and surprisingly accurate expression for g1(r) . The structure of a discrete “core-softened” model for liquids with anomalous thermodynamic properties is reproduced as an application.
Scaling laws and triviality bounds in the lattice Φ4 theory. Pt. 1
International Nuclear Information System (INIS)
Luescher, M.; Weisz, P.
1987-01-01
The lattice Φ 4 theory in four space-time dimensions is most likely 'trivial', i.e. its continuum limit is a free field theory. However, for small but positive lattice spacing a and at energies well below the cutoff mass Λ=1/a, the theory effectively behaves like a continuum theory with particle interactions, which may be appreciable. By a combination of known analytical methods, we here determine the maximal value of the renormalized coupling at zero momentum as a function of Λ/m, where m denotes the mass of the scalar particle in the theory. Moreover, a complete solution of the model is obtained in the sense that all low energy amplitudes can be computed with reasonable estimated accuracy for arbitrarily chosen bare coupling and mass in the symmetric phase region. (orig.)
Influence of chamber misalignment on cased telescoped (CT ammunition accuracy
Directory of Open Access Journals (Sweden)
D. Corriveau
2016-04-01
Full Text Available As part of a research program, it was desired to better understand the impact of the rotating chamber alignment with the barrel throat on the precision and accuracy of a novel cased telescoped (CT ammunition firing rifle. In order to perform the study, a baseline CT ammunition chamber which was concentric with a Mann barrel bore was manufactured. Additionally, six chambers were manufactured with an offset relative to the barrel bore. These chambers were used to simulate a misaligned chamber relative to the bore axis. Precision and accuracy tests were then performed at 200 m in an indoor range under controlled conditions. For this project, 5.56 mm CT ammunition was used. As the chamber axis offset relative to the gun bore was increased, the mean point of impact was displaced away from the target center. The shift in the impact location is explained by the presence of in-bore yaw which results in lateral throw-off and aerodynamic jump components. The linear theory of ballistics is used to establish a relationship between the chamber misalignment and the resulting projectile mean point of impact for a rifle developed to fire CT ammunition. This relationship allows for the prediction of the mean point of impact given a chamber misalignment.
Improving shuffler assay accuracy
International Nuclear Information System (INIS)
Rinard, P.M.
1995-01-01
Drums of uranium waste should be disposed of in an economical and environmentally sound manner. The most accurate possible assays of the uranium masses in the drums are required for proper disposal. The accuracies of assays from a shuffler are affected by the type of matrix material in the drums. Non-hydrogenous matrices have little effect on neutron transport and accuracies are very good. If self-shielding is known to be a minor problem, good accuracies are also obtained with hydrogenous matrices when a polyethylene sleeve is placed around the drums. But for those cases where self-shielding may be a problem, matrices are hydrogenous, and uranium distributions are non-uniform throughout the drums, the accuracies are degraded. They can be greatly improved by determining the distributions of the uranium and then applying correction factors based on the distributions. This paper describes a technique for determining uranium distributions by using the neutron count rates in detector banks around the waste drum and solving a set of overdetermined linear equations. Other approaches were studied to determine the distributions and are described briefly. Implementation of this correction is anticipated on an existing shuffler next year
Eriksen, Janus J; Matthews, Devin A; Jørgensen, Poul; Gauss, Jürgen
2016-05-21
We extend our assessment of the potential of perturbative coupled cluster (CC) expansions for a test set of open-shell atoms and organic radicals to the description of quadruple excitations. Namely, the second- through sixth-order models of the recently proposed CCSDT(Q-n) quadruples series [J. J. Eriksen et al., J. Chem. Phys. 140, 064108 (2014)] are compared to the prominent CCSDT(Q) and ΛCCSDT(Q) models. From a comparison of the models in terms of their recovery of total CC singles, doubles, triples, and quadruples (CCSDTQ) energies, we find that the performance of the CCSDT(Q-n) models is independent of the reference used (unrestricted or restricted (open-shell) Hartree-Fock), in contrast to the CCSDT(Q) and ΛCCSDT(Q) models, for which the accuracy is strongly dependent on the spin of the molecular ground state. By further comparing the ability of the models to recover relative CCSDTQ total atomization energies, the discrepancy between them is found to be even more pronounced, stressing how a balanced description of both closed- and open-shell species-as found in the CCSDT(Q-n) models-is indeed of paramount importance if any perturbative CC model is to be of chemical relevance for high-accuracy applications. In particular, the third-order CCSDT(Q-3) model is found to offer an encouraging alternative to the existing choices of quadruples models used in modern computational thermochemistry, since the model is still only of moderate cost, albeit markedly more costly than, e.g., the CCSDT(Q) and ΛCCSDT(Q) models.
Eriksen, Janus J; Matthews, Devin A; Jørgensen, Poul; Gauss, Jürgen
2016-05-21
The accuracy at which total energies of open-shell atoms and organic radicals may be calculated is assessed for selected coupled cluster perturbative triples expansions, all of which augment the coupled cluster singles and doubles (CCSD) energy by a non-iterative correction for the effect of triple excitations. Namely, the second- through sixth-order models of the recently proposed CCSD(T-n) triples series [J. J. Eriksen et al., J. Chem. Phys. 140, 064108 (2014)] are compared to the acclaimed CCSD(T) model for both unrestricted as well as restricted open-shell Hartree-Fock (UHF/ROHF) reference determinants. By comparing UHF- and ROHF-based statistical results for a test set of 18 modest-sized open-shell species with comparable RHF-based results, no behavioral differences are observed for the higher-order models of the CCSD(T-n) series in their correlated descriptions of closed- and open-shell species. In particular, we find that the convergence rate throughout the series towards the coupled cluster singles, doubles, and triples (CCSDT) solution is identical for the two cases. For the CCSD(T) model, on the other hand, not only its numerical consistency, but also its established, yet fortuitous cancellation of errors breaks down in the transition from closed- to open-shell systems. The higher-order CCSD(T-n) models (orders n > 3) thus offer a consistent and significant improvement in accuracy relative to CCSDT over the CCSD(T) model, equally for RHF, UHF, and ROHF reference determinants, albeit at an increased computational cost.
Energy Technology Data Exchange (ETDEWEB)
Eriksen, Janus J., E-mail: janusje@chem.au.dk; Jørgensen, Poul [qLEAP Center for Theoretical Chemistry, Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Matthews, Devin A. [The Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712 (United States); Gauss, Jürgen [Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, D-55128 Mainz (Germany)
2016-05-21
The accuracy at which total energies of open-shell atoms and organic radicals may be calculated is assessed for selected coupled cluster perturbative triples expansions, all of which augment the coupled cluster singles and doubles (CCSD) energy by a non-iterative correction for the effect of triple excitations. Namely, the second- through sixth-order models of the recently proposed CCSD(T–n) triples series [J. J. Eriksen et al., J. Chem. Phys. 140, 064108 (2014)] are compared to the acclaimed CCSD(T) model for both unrestricted as well as restricted open-shell Hartree-Fock (UHF/ROHF) reference determinants. By comparing UHF- and ROHF-based statistical results for a test set of 18 modest-sized open-shell species with comparable RHF-based results, no behavioral differences are observed for the higher-order models of the CCSD(T–n) series in their correlated descriptions of closed- and open-shell species. In particular, we find that the convergence rate throughout the series towards the coupled cluster singles, doubles, and triples (CCSDT) solution is identical for the two cases. For the CCSD(T) model, on the other hand, not only its numerical consistency, but also its established, yet fortuitous cancellation of errors breaks down in the transition from closed- to open-shell systems. The higher-order CCSD(T–n) models (orders n > 3) thus offer a consistent and significant improvement in accuracy relative to CCSDT over the CCSD(T) model, equally for RHF, UHF, and ROHF reference determinants, albeit at an increased computational cost.
Directory of Open Access Journals (Sweden)
Braz Baracuhy
2006-12-01
Full Text Available O artigo analisa a natureza da política externa brasileira na crise da Liga das Nações (1926, a partir de modelo teórico do realismo neoclássico. As dinâmicas por posições de poder nos tabuleiros geopolítico e multilateral do sistema internacional e as percepções e estratégias diplomáticas da elite de política externa brasileira são consideradas no estudo teórico.The article analyzes the nature of Brazilian foreign policy in the crisis of the League of Nations (1926 from a neoclassical-realist theoretical perspective. Within this theoretical framework, the dynamics of power positioning in the geopolitical and multilateral chessboards of the international system and the perceptions and diplomatic strategies of the Brazilian foreign-policy elite are taken into account.
St-Onge, Christina; Valois, Pierre; Abdous, Belkacem; Germain, Stephane
2009-01-01
To date, there have been no studies comparing parametric and nonparametric Item Characteristic Curve (ICC) estimation methods on the effectiveness of Person-Fit Statistics (PFS). The primary aim of this study was to determine if the use of ICCs estimated by nonparametric methods would increase the accuracy of item response theory-based PFS for…
Theory of mind selectively predicts preschoolers' knowledge-based selective word learning.
Brosseau-Liard, Patricia; Penney, Danielle; Poulin-Dubois, Diane
2015-11-01
Children can selectively attend to various attributes of a model, such as past accuracy or physical strength, to guide their social learning. There is a debate regarding whether a relation exists between theory-of-mind skills and selective learning. We hypothesized that high performance on theory-of-mind tasks would predict preference for learning new words from accurate informants (an epistemic attribute), but not from physically strong informants (a non-epistemic attribute). Three- and 4-year-olds (N = 65) completed two selective learning tasks, and their theory-of-mind abilities were assessed. As expected, performance on a theory-of-mind battery predicted children's preference to learn from more accurate informants but not from physically stronger informants. Results thus suggest that preschoolers with more advanced theory of mind have a better understanding of knowledge and apply that understanding to guide their selection of informants. This work has important implications for research on children's developing social cognition and early learning. © 2015 The British Psychological Society.
Theory of mind selectively predicts preschoolers’ knowledge-based selective word learning
Brosseau-Liard, Patricia; Penney, Danielle; Poulin-Dubois, Diane
2015-01-01
Children can selectively attend to various attributes of a model, such as past accuracy or physical strength, to guide their social learning. There is a debate regarding whether a relation exists between theory-of-mind skills and selective learning. We hypothesized that high performance on theory-of-mind tasks would predict preference for learning new words from accurate informants (an epistemic attribute), but not from physically strong informants (a non-epistemic attribute). Three- and 4-year-olds (N = 65) completed two selective learning tasks, and their theory of mind abilities were assessed. As expected, performance on a theory-of-mind battery predicted children’s preference to learn from more accurate informants but not from physically stronger informants. Results thus suggest that preschoolers with more advanced theory of mind have a better understanding of knowledge and apply that understanding to guide their selection of informants. This work has important implications for research on children’s developing social cognition and early learning. PMID:26211504
How could the replica method improve accuracy of performance assessment of channel coding?
Energy Technology Data Exchange (ETDEWEB)
Kabashima, Yoshiyuki [Department of Computational Intelligence and Systems Science, Tokyo Institute of technology, Yokohama 226-8502 (Japan)], E-mail: kaba@dis.titech.ac.jp
2009-12-01
We explore the relation between the techniques of statistical mechanics and information theory for assessing the performance of channel coding. We base our study on a framework developed by Gallager in IEEE Trans. Inform. Theory IT-11, 3 (1965), where the minimum decoding error probability is upper-bounded by an average of a generalized Chernoff's bound over a code ensemble. We show that the resulting bound in the framework can be directly assessed by the replica method, which has been developed in statistical mechanics of disordered systems, whereas in Gallager's original methodology further replacement by another bound utilizing Jensen's inequality is necessary. Our approach associates a seemingly ad hoc restriction with respect to an adjustable parameter for optimizing the bound with a phase transition between two replica symmetric solutions, and can improve the accuracy of performance assessments of general code ensembles including low density parity check codes, although its mathematical justification is still open.
Rapp, Richard H.
1993-01-01
The determination of the geoid and equipotential surface of the Earth's gravity field, has long been of interest to geodesists and oceanographers. The geoid provides a surface to which the actual ocean surface can be compared with the differences implying information on the circulation patterns of the oceans. For use in oceanographic applications the geoid is ideally needed to a high accuracy and to a high resolution. There are applications that require geoid undulation information to an accuracy of +/- 10 cm with a resolution of 50 km. We are far from this goal today but substantial improvement in geoid determination has been made. In 1979 the cumulative geoid undulation error to spherical harmonic degree 20 was +/- 1.4 m for the GEM10 potential coefficient model. Today the corresponding value has been reduced to +/- 25 cm for GEM-T3 or +/- 11 cm for the OSU91A model. Similar improvements are noted by harmonic degree (wave-length) and in resolution. Potential coefficient models now exist to degree 360 based on a combination of data types. This paper discusses the accuracy changes that have taken place in the past 12 years in the determination of geoid undulations.
The Lamb shift in muonic hydrogen and the proton radius from effective field theories
Energy Technology Data Exchange (ETDEWEB)
Peset, Clara; Pineda, Antonio [Universitat Autonoma de Barcelona, Grup de Fisica Teorica, Dept. Fisica and IFAE, Bellaterra (Barcelona) (Spain)
2015-12-15
We comprehensively analyse the theoretical prediction for the Lamb shift in muonic hydrogen, and the associated determination of the proton radius. We use effective field theories. This allows us to relate the proton radius with well-defined objects in quantum field theory, eliminating unnecessary model dependence. The use of effective field theories also helps us to organize the computation so that we can clearly state the parametric accuracy of the result. In this paper we review all (and check several of) the contributions to the energy shift of order α{sup 5}, as well as those that scale like α{sup 6} x logarithms in the context of non-relativistic effective field theories of QED. (orig.)
Accuracy, convergence and stability of finite element CFD algorithms
International Nuclear Information System (INIS)
Baker, A.J.; Iannelli, G.S.; Noronha, W.P.
1989-01-01
The requirement for artificial dissipation is well understood for shock-capturing CFD procedures in aerodynamics. However, numerical diffusion is widely utilized across the board in Navier-Stokes CFD algorithms, ranging from incompressible through supersonic flow applications. The Taylor weak statement (TWS) theory is applicable to any conservation law system containing an evolutionary component, wherein the analytical modifications becomes functionally dependent on the Jacobian of the corresponding equation system flux vector. The TWS algorithm is developed for a range of fluid mechanics conservation law systems including incompressible Navier-Stokes, depth-averaged free surface hydrodynamic Navier-Stokes, and the compressible Euler and Navier-Stokes equations. This paper presents the TWS statement for the problem class range and highlights the important theoretical issues of accuracy, convergence and stability. Numerical results for a variety of benchmark problems are presented to document key features. 8 refs
Optical approximation in the theory of geometric impedance
International Nuclear Information System (INIS)
Stupakov, G.; Bane, K.L.F.; Zagorodnov, I.
2007-02-01
In this paper we introduce an optical approximation into the theory of impedance calculation, one valid in the limit of high frequencies. This approximation neglects diffraction effects in the radiation process, and is conceptually equivalent to the approximation of geometric optics in electromagnetic theory. Using this approximation, we derive equations for the longitudinal impedance for arbitrary offsets, with respect to a reference orbit, of source and test particles. With the help of the Panofsky-Wenzel theorem we also obtain expressions for the transverse impedance (also for arbitrary offsets). We further simplify these expressions for the case of the small offsets that are typical for practical applications. Our final expressions for the impedance, in the general case, involve two dimensional integrals over various cross-sections of the transition. We further demonstrate, for several known axisymmetric examples, how our method is applied to the calculation of impedances. Finally, we discuss the accuracy of the optical approximation and its relation to the diffraction regime in the theory of impedance. (orig.)
In your eyes: does theory of mind predict impaired life functioning in bipolar disorder?
Purcell, Amanda L; Phillips, Mary; Gruber, June
2013-12-01
Deficits in emotion perception and social functioning are strongly implicated in bipolar disorder (BD). Examining theory of mind (ToM) may provide one potential mechanism to explain observed socio-emotional impairments in this disorder. The present study prospectively investigated the relationship between theory of mind performance and life functioning in individuals diagnosed with BD compared to unipolar depression and healthy control groups. Theory of mind (ToM) performance was examined in 26 individuals with remitted bipolar I disorder (BD), 29 individuals with remitted unipolar depression (UD), and 28 healthy controls (CTL) using a well-validated advanced theory of mind task. Accuracy and response latency scores were calculated from the task. Life functioning was measured during a 12 month follow-up session. No group differences for ToM accuracy emerged. However, the BD group exhibited significantly shorter response times than the UD and CTL groups. Importantly, quicker response times in the BD group predicted greater life functioning impairment at a 12-month follow-up, even after controlling for baseline symptoms. The stimuli were static representations of emotional states and do not allow for evaluating the appropriateness of context during emotional communication; due to sample size, neither specific comorbidities nor medication effects were analyzed for the BD and UD groups; preliminary status of theory of mind as a construct. Results suggest that quickened socio-emotional decision making may represent a risk factor for future functional impairment in BD. Copyright © 2013 Elsevier B.V. All rights reserved.
Rolling bearing fault diagnosis based on information fusion using Dempster-Shafer evidence theory
Pei, Di; Yue, Jianhai; Jiao, Jing
2017-10-01
This paper presents a fault diagnosis method for rolling bearing based on information fusion. Acceleration sensors are arranged at different position to get bearing vibration data as diagnostic evidence. The Dempster-Shafer (D-S) evidence theory is used to fuse multi-sensor data to improve diagnostic accuracy. The efficiency of the proposed method is demonstrated by the high speed train transmission test bench. The results of experiment show that the proposed method in this paper improves the rolling bearing fault diagnosis accuracy compared with traditional signal analysis methods.
Drach-Zahavy, Anat; Broyer, Chaya; Dagan, Efrat
2017-09-01
Shared mental models are crucial for constructing mutual understanding of the patient's condition during a clinical handover. Yet, scant research, if any, has empirically explored mental models of the parties involved in a clinical handover. This study aimed to examine the similarities among mental models of incoming and outgoing nurses, and to test their accuracy by comparing them with mental models of expert nurses. A cross-sectional study, exploring nurses' mental models via the concept mapping technique. 40 clinical handovers. Data were collected via concept mapping of the incoming, outgoing, and expert nurses' mental models (total of 120 concept maps). Similarity and accuracy for concepts and associations indexes were calculated to compare the different maps. About one fifth of the concepts emerged in both outgoing and incoming nurses' concept maps (concept similarity=23%±10.6). Concept accuracy indexes were 35%±18.8 for incoming and 62%±19.6 for outgoing nurses' maps. Although incoming nurses absorbed fewer number of concepts and associations (23% and 12%, respectively), they partially closed the gap (35% and 22%, respectively) relative to expert nurses' maps. The correlations between concept similarities, and incoming as well as outgoing nurses' concept accuracy, were significant (r=0.43, p<0.01; r=0.68 p<0.01, respectively). Finally, in 90% of the maps, outgoing nurses added information concerning the processes enacted during the shift, beyond the expert nurses' gold standard. Two seemingly contradicting processes in the handover were identified. "Information loss", captured by the low similarity indexes among the mental models of incoming and outgoing nurses; and "information restoration", based on accuracy measures indexes among the mental models of the incoming nurses. Based on mental model theory, we propose possible explanations for these processes and derive implications for how to improve a clinical handover. Copyright © 2017 Elsevier Ltd. All
Relativistic theory for syntonization of clocks in the vicinity of the Earth
Wolf, Peter; Petit, G.
1995-01-01
A well known prediction of Einstein's general theory of relativity states that two ideal clocks that move with a relative velocity, and are submitted to different gravitational fields will, in general, be observed to run at different rates. Similarly the rate of a clock with respect to the coordinate time of some spacetime reference system is dependent on the velocity of the clock in that reference system and on the gravitational fields it is submitted to. For the syntonization of clocks and the realization of coordinate times (like TAI) this rate shift has to be taken into account at an accuracy level which should be below the frequency stability of the clocks in question, i.e. all terms that are larger than the instability of the clocks should be corrected for. We present a theory for the calculation of the relativistic rate shift for clocks in the vicinity of the Earth, including all terms larger than one part in 10(exp 18). This, together with previous work on clock synchronization (Petit & Wolf 1993, 1994), amounts to a complete relativistic theory for the realization of coordinate time scales at picosecond synchronization and 10(exp -18) syntonization accuracy, which should be sufficient to accommodate future developments in time transfer and clock technology.
Viscosity Prediction for Petroleum Fluids Using Free Volume Theory and PC-SAFT
Khoshnamvand, Younes; Assareh, Mehdi
2018-04-01
In this study, free volume theory ( FVT) in combination with perturbed-chain statistical associating fluid theory is implemented for viscosity prediction of petroleum reservoir fluids containing ill-defined components such as cuts and plus fractions. FVT has three adjustable parameters for each component to calculate viscosity. These three parameters for petroleum cuts (especially plus fractions) are not available. In this work, these parameters are determined for different petroleum fractions. A model as a function of molecular weight and specific gravity is developed using 22 real reservoir fluid samples with API grades in the range of 22 to 45. Afterward, the proposed model accuracy in comparison with the accuracy of De la Porte et al. with reference to experimental data is presented. The presented model is used for six real samples in an evaluation step, and the results are compared with available experimental data and the method of De la Porte et al. Finally, the method of Lohrenz et al. and the method of Pedersen et al. as two common industrial methods for viscosity calculation are compared with the proposed approach. The absolute average deviation was 9.7 % for free volume theory method, 15.4 % for Lohrenz et al., and 22.16 for Pedersen et al.
Models and methods can theory meet the B physics challenge?
Nierste, U
2004-01-01
The B physics experiments of the next generation, BTeV and LHCb, will perform measurements with an unprecedented accuracy. Theory predictions must control hadronic uncertainties with the same precision to extract the desired short-distance information successfully. I argue that this is indeed possible, discuss those theoretical methods in which hadronic uncertainties are under control and list hadronically clean observables.
Rare, but obviously there: effects of target frequency and salience on visual search accuracy.
Biggs, Adam T; Adamo, Stephen H; Mitroff, Stephen R
2014-10-01
Accuracy can be extremely important for many visual search tasks. However, numerous factors work to undermine successful search. Several negative influences on search have been well studied, yet one potentially influential factor has gone almost entirely unexplored-namely, how is search performance affected by the likelihood that a specific target might appear? A recent study demonstrated that when specific targets appear infrequently (i.e., once in every thousand trials) they were, on average, not often found. Even so, some infrequently appearing targets were actually found quite often, suggesting that the targets' frequency is not the only factor at play. Here, we investigated whether salience (i.e., the extent to which an item stands out during search) could explain why some infrequent targets are easily found whereas others are almost never found. Using the mobile application Airport Scanner, we assessed how individual target frequency and salience interacted in a visual search task that included a wide array of targets and millions of trials. Target frequency and salience were both significant predictors of search accuracy, although target frequency explained more of the accuracy variance. Further, when examining only the rarest target items (those that appeared on less than 0.15% of all trials), there was a significant relationship between salience and accuracy such that less salient items were less likely to be found. Beyond implications for search theory, these data suggest significant vulnerability for real-world searches that involve targets that are both infrequent and hard-to-spot. Copyright © 2014 Elsevier B.V. All rights reserved.
Burnos, Piotr; Rys, Dawid
2017-09-07
Weigh-in-Motion systems are tools to prevent road pavements from the adverse phenomena of vehicle overloading. However, the effectiveness of these systems can be significantly increased by improving weighing accuracy, which is now insufficient for direct enforcement of overloaded vehicles. Field tests show that the accuracy of Weigh-in-Motion axle load sensors installed in the flexible (asphalt) pavements depends on pavement temperature and vehicle speeds. Although this is a known phenomenon, it has not been explained yet. The aim of our study is to fill this gap in the knowledge. The explanation of this phenomena which is presented in the paper is based on pavement/sensors mechanics and the application of the multilayer elastic half-space theory. We show that differences in the distribution of vertical and horizontal stresses in the pavement structure are the cause of vehicle weight measurement errors. These studies are important in terms of Weigh-in-Motion systems for direct enforcement and will help to improve the weighing results accuracy.
Directory of Open Access Journals (Sweden)
Shelley M. ALEXANDER
2009-02-01
Full Text Available We compared probability surfaces derived using one set of environmental variables in three Geographic Information Systems (GIS-based approaches: logistic regression and Akaike’s Information Criterion (AIC, Multiple Criteria Evaluation (MCE, and Bayesian Analysis (specifically Dempster-Shafer theory. We used lynx Lynx canadensis as our focal species, and developed our environment relationship model using track data collected in Banff National Park, Alberta, Canada, during winters from 1997 to 2000. The accuracy of the three spatial models were compared using a contingency table method. We determined the percentage of cases in which both presence and absence points were correctly classified (overall accuracy, the failure to predict a species where it occurred (omission error and the prediction of presence where there was absence (commission error. Our overall accuracy showed the logistic regression approach was the most accurate (74.51%. The multiple criteria evaluation was intermediate (39.22%, while the Dempster-Shafer (D-S theory model was the poorest (29.90%. However, omission and commission error tell us a different story: logistic regression had the lowest commission error, while D-S theory produced the lowest omission error. Our results provide evidence that habitat modellers should evaluate all three error measures when ascribing confidence in their model. We suggest that for our study area at least, the logistic regression model is optimal. However, where sample size is small or the species is very rare, it may also be useful to explore and/or use a more ecologically cautious modelling approach (e.g. Dempster-Shafer that would over-predict, protect more sites, and thereby minimize the risk of missing critical habitat in conservation plans[Current Zoology 55(1: 28 – 40, 2009].
Item response theory - A first approach
Nunes, Sandra; Oliveira, Teresa; Oliveira, Amílcar
2017-07-01
The Item Response Theory (IRT) has become one of the most popular scoring frameworks for measurement data, frequently used in computerized adaptive testing, cognitively diagnostic assessment and test equating. According to Andrade et al. (2000), IRT can be defined as a set of mathematical models (Item Response Models - IRM) constructed to represent the probability of an individual giving the right answer to an item of a particular test. The number of Item Responsible Models available to measurement analysis has increased considerably in the last fifteen years due to increasing computer power and due to a demand for accuracy and more meaningful inferences grounded in complex data. The developments in modeling with Item Response Theory were related with developments in estimation theory, most remarkably Bayesian estimation with Markov chain Monte Carlo algorithms (Patz & Junker, 1999). The popularity of Item Response Theory has also implied numerous overviews in books and journals, and many connections between IRT and other statistical estimation procedures, such as factor analysis and structural equation modeling, have been made repeatedly (Van der Lindem & Hambleton, 1997). As stated before the Item Response Theory covers a variety of measurement models, ranging from basic one-dimensional models for dichotomously and polytomously scored items and their multidimensional analogues to models that incorporate information about cognitive sub-processes which influence the overall item response process. The aim of this work is to introduce the main concepts associated with one-dimensional models of Item Response Theory, to specify the logistic models with one, two and three parameters, to discuss some properties of these models and to present the main estimation procedures.
LENUS (Irish Health Repository)
Martin, S T
2012-02-01
BACKGROUND: A variety of approaches are available for division of major vascular structures during laparoscopic colorectal resection. Ultrasonic coagulating shears (UCS), vascular staplers, plastic or titanium clips and electrothermal bipolar vessel sealing (EBVS) are currently available. We report our experience with an EBVS device, LigaSure (Covidien AG), used in division of the ileocolic, middle colic and inferior mesenteric arteries during laparoscopic colorectal resection. METHODS: We report the immediate outcome of 802 consecutive unselected patients who underwent elective laparoscopic colorectal cancer resection performed with use of the LigaSure (5 and 10 mm) at our institution over a 5-year period. Operative procedures included right hemicolectomy (n = 180), left hemicolectomy (n = 96), sigmoid colectomy (n = 347) and anterior resection (n = 179). Data were collected from a prospectively maintained cancer database and operative records. The procedures were performed primarily by three consultant surgeons with an interest in laparoscopic colorectal resection. RESULTS: Of 802 cases in which the LigaSure device was employed to divide major vascular structures, immediate effective vessel sealing was achieved in 99.8% (n = 800). Two patients experienced related adverse events both following division of the inferior mesenteric artery with a 5 mm LigaSure. Both patients had immediate uncontrolled haemorrhage that required laparotomy. CONCLUSIONS: Use of the LigaSure device to seal and divide the major mesenteric vessels during laparoscopic colorectal resection is very effective, with a high success rate of 99.8%. Caution should be exercised in elderly atherosclerotic patients, particularly when using the 5-mm LigaSure device.
Comparison of beam and shell theories for the vibrations of thin turbomachinery blades
Leissa, A. W.; Ewing, M. S.
1982-01-01
Vibration analysis of turbomachinery blades has traditionally been carried out by means of beam theory. In recent years two-dimensional methods of blade vibration analysis have been developed, most of which utilize finite elements and tend to require considerable computation time. More recently a two-dimensional method of blade analysis has evolved which does not require finite elements and is based upon shell equations. The present investigation has the primary objective to demonstrate the accuracy and limitations of blade vibration analyses which utilize one-dimensional, beam theories. It is found that beam theory is generally inadequate to determine the free vibration frequencies and mode shapes of moderate to low aspect ratio turbomachinery blades. The shallow shell theory, by contrast, is capable of representing all the vibration modes accurately. However, the one-dimensional beam theory has an important advantage over the two-dimensional shell theory for blades and vibration modes. It uses fewer degrees of freedom, thus requiring less computer time.
Examining the accuracy of the infinite order sudden approximation using sensitivity analysis
International Nuclear Information System (INIS)
Eno, L.; Rabitz, H.
1981-01-01
A method is developed for assessing the accuracy of scattering observables calculated within the framework of the infinite order sudden (IOS) approximation. In particular, we focus on the energy sudden assumption of the IOS method and our approach involves the determination of the sensitivity of the IOS scattering matrix S/sup IOS/ with respect to a parameter which reintroduces the internal energy operator h 0 into the IOS Hamiltonian. This procedure is an example of sensitivity analysis of missing model components (h 0 in this case) in the reference Hamiltonian. In contrast to simple first-order perturbation theory a finite result is obtained for the effect of h 0 on S/sup IOS/. As an illustration, our method of analysis is applied to integral state-to-state cross sections for the scattering of an atom and rigid rotor. Results are generated within the He+H 2 system and a comparison is made between IOS and coupled states cross sections and the corresponding IOS sensitivities. It is found that the sensitivity coefficients are very useful indicators of the accuracy of the IOS results. Finally, further developments and applications are discussed
Time-dependent restricted-active-space self-consistent-field theory for bosonic many-body systems
International Nuclear Information System (INIS)
Lévêque, Camille; Madsen, Lars Bojer
2017-01-01
We develop an ab initio time-dependent wavefunction based theory for the description of a many-body system of cold interacting bosons. Like the multi-configurational time-dependent Hartree method for bosons (MCTDHB), the theory is based on a configurational interaction Ansatz for the many-body wavefunction with time-dependent self-consistent-field orbitals. The theory generalizes the MCTDHB method by incorporating restrictions on the active space of the orbital excitations. The restrictions are specified based on the physical situation at hand. The equations of motion of this time-dependent restricted-active-space self-consistent-field (TD-RASSCF) theory are derived. The similarity between the formal development of the theory for bosons and fermions is discussed. The restrictions on the active space allow the theory to be evaluated under conditions where other wavefunction based methods due to exponential scaling in the numerical effort cannot, and to clearly identify the excitations that are important for an accurate description, significantly beyond the mean-field approach. For ground state calculations we find it to be important to allow a few particles to have the freedom to move in many orbitals, an insight facilitated by the flexibility of the restricted-active-space Ansatz . Moreover, we find that a high accuracy can be obtained by including only even excitations in the many-body self-consistent-field wavefunction. Time-dependent simulations of harmonically trapped bosons subject to a quenching of their noncontact interaction, show failure of the mean-field Gross-Pitaevskii approach within a fraction of a harmonic oscillation period. The TD-RASSCF theory remains accurate at much reduced computational cost compared to the MCTDHB method. Exploring the effect of changes of the restricted-active-space allows us to identify that even self-consistent-field excitations are mainly responsible for the accuracy of the method. (paper)
Directory of Open Access Journals (Sweden)
João del GIUDICE-NETO
2004-12-01
Full Text Available Este artigo apresenta o estudo davariação isoenzimática em Caesalpinia echinata L.(pau-brasil. Onze sistemas enzimáticos (ACP,DIA, EST, G6PDH, GOT, LAP, MDH, PGI, PRX,SKDH e 6PGDH codificando dezoito locos (Acp-1,Est-3, Dia-1, G6pdh-1, Got-1, Lap-1, Mdh-1,Mdh-2, Mdh-3, Pgi-1, Pgi-2, Prx-1, Prx-2, Prx-3,Prx-4, Skdh-1, 6pgdh-1 e 6pgdh-2 foraminvestigados. Entre esses locos, Pgi-1 e Got-1foram detectados como monomórficos. Três locos(Mdh-2, G6pdh-1 e 6pgdh-1 não tiveram suaherança analisada devido à ausência de progênies deárvores heterozigotas na amostra. A herançamendeliana simples foi confirmada para dez locos(Acp-1, Dia-1, Est-3, Lap-1, Mdh-1, Mdh-3, Prx-1,Prx-3, Skdh-1 e 6pgdh-2. Três locos (Pgi-2, Prx-2e Prx-4 apresentaram desvios altamentesignificativos (P < 0,01 para a hipótese desegregação regular 1:1. As relações dedesequilíbrios de ligações foram avaliadas em 120pares de locos isoenzimáticos. Seis pares de locosapresentaram ligação: Mdh-3:Dia-1, Mdh-3:Prx-3,6pgdh-1:Pgi-2, 6pgdh-1:Prx-1, 6pgdh-2:Prx-3 ePgi-2:Prx-4.This article presents a study of isozymevariation in Caesalpinia echinata L. (brazilwood.Eleven isozyme systems (ACP, DIA, EST,G6PDH, GOT, LAP, MDH, PGI, PRX, SKDH and6PGDH codifying eighteen loci (Acp-1, Est-3,Dia-1, G6pdh-1, Got-1, Lap-1, Mdh-1, Mdh-2,Mdh-3, Pgi-1, Pgi-2, Prx-1, Prx-2, Prx-3, Prx-4,Skdh-1, 6pgdh-1 and 6pgdh-2 were investigated.Among these loci, Pgi-1 and Got-1 weremonomorphic. Three loci (Mdh-2, G6pdh-1 and6pgdh-1 were not evaluated for inheritance duethe lack of families from heterozygous mothertrees in the sampling. Mendelian inheritance wasconfirmed for ten allozyme loci (Acp-1, Dia-1,Est-3, Lap-1, Mdh-1, Mdh-3, Prx-1, Prx-3, Skdh-1,and 6pgdh-2. Three loci (Pgi-2, Prx-2 and Prx-4showed significant deviations (P < 0.01 from expectedsegregation 1:1 hypothesis. Linkage relationshipswere examined for 120 pairs of allozyme loci.Six pairs of loci showed linked: Mdh-3:Dia-1,Mdh-3:Prx-3, 6
Accuracy of a selection criterion for glass forming ability in the Ni–Nb–Zr system
International Nuclear Information System (INIS)
Déo, L.P.; Oliveira, M.F. de
2014-01-01
Highlights: • We applied a selection in the Ni–Nb–Zr system to find alloys with high GFA. • We used the thermal parameter γ m to evaluate the GFA of alloys. • The correlation between the γ m parameter and R c in the studied system is poor. • The effect of oxygen impurity reduced dramatically the GFA of alloys. • Unknown intermetallic compounds reduced the accuracy of the criterion. - Abstract: Several theories have been developed and applied in metallic systems in order to find the best stoichiometries with high glass forming ability; however there is no universal theory to predict the glass forming ability in metallic systems. Recently a selection criterion was applied in the Zr–Ni–Cu system and it was found some correlation between experimental and theoretical data. This criterion correlates critical cooling rate for glass formation with topological instability of stable crystalline structures; average work function difference and average electron density difference among the constituent elements of the alloy. In the present work, this criterion was applied in the Ni–Nb–Zr system. It was investigated the influence of factors not considered in the calculation and on the accuracy of the criterion, such as unknown intermetallic compounds and oxygen contamination. Bulk amorphous specimens were produced by injection casting. The amorphous nature was analyzed by X-ray diffraction and differential scanning calorimetry; oxygen contamination was quantified by the inert gas fusion method
Sturmians and generalized sturmians in quantum theory
DEFF Research Database (Denmark)
Avery, John Scales; Avery, James Emil
2012-01-01
The theory of Sturmians and generalized Sturmians is reviewed. It is shown that when generalized Sturmians are used as basis functions, calculations on the spectra and physical properties of few-electron atoms can be performed with great ease and good accuracy. The use of many-center Coulomb Stur...... Sturmians as basis functions in calculations on N-electron molecules is also discussed. Basis sets of this type are shown to have many advantages over other types of ETO’s, especially the property of automatic scaling....
An Integrated Theory of Attention and Decision Making in Visual Signal Detection
Smith, Philip L.; Ratcliff, Roger
2009-01-01
The simplest attentional task, detecting a cued stimulus in an otherwise empty visual field, produces complex patterns of performance. Attentional cues interact with backward masks and with spatial uncertainty, and there is a dissociation in the effects of these variables on accuracy and on response time. A computational theory of performance in…
Accuracy limits on rapid assessment of gently varying bathymetry
McDonald, B. Edward; Holland, Charles
2002-05-01
Accuracy limits for rapidly probing shallow water bathymetry are investigated as a function of bottom slope and other relevant parameters. The probe scheme [B. E. McDonald and Charles Holland, J. Acoust. Soc. Am. 110, 2767 (2001)] uses a time reversed mirror (TRM) to ensonify a thin annulus on the ocean bottom at ranges of a few km from a vertical send/ receive array. The annulus is shifted in range by variable bathymetry (perturbation theory shows that the focal annulus experiences a radial shift proportional to the integrated bathymetry along a given azimuth). The range shift implies an azimuth-dependent time of maximum reverberation. Thus the reverberant return contains information that might be inverted to give bathymetric parameters. The parameter range over which the perturbation result is accurate is explored using the RAM code for propagation in arbitrarily range-dependent environments. [Work supported by NRL.
Prediction of the liquid-vapor equilibrium pressure using the quasi-Gaussian entropy theory
Amadei, A; Roccatano, D; Apol, M.E F; Berendsen, H.J.C.; Di Nola, A.
1996-01-01
We derived a method to evaluate the liquid-vapor equilibrium pressure, with high accuracy over a large range of temperature, using the quasi-Gaussian entropy theory. The final expression that we obtain for the equilibrium pressure as a function of the temperature can be considered as a very accurate
A technique for analytical calculation of observables in lattice gauge theories
International Nuclear Information System (INIS)
Narayanan, R.; Vranas, P.
1990-01-01
It is shown that the partition function for a finite lattice factorizes into terms that can be associated with each vertex in the finite lattice. This factorization property forms the basis of well defined and efficient technique developed to calculate partition functions to high accuracy, on finite lattices for gauge theories. This technique along with the expansion in finite lattices, provides a powerful means for calculating observables in lattice gauge theories. This is applied to SU(2) lattice gauge theory in four dimensions. The free energy, expectation value of a plaquette and specific heat are calculated. The results are very good in the strong coupling region, succeed in entering the weak coupling region and describe the crossover region quite well, agreeing all the way with the Monte Carlo data. (orig.)
Parquet theory in nuclear structure calculations
International Nuclear Information System (INIS)
Bergli, Elise
2010-01-01
The thesis concerns a numerical implementation of the Parquet summation of diagrams within Green's functions theory applied to calculations of nuclear systems. The main motivation has been to investigate whether it is possible to develop this approach to a level comparable in accuracy and reliability to other ab initio nuclear structure methods. The Green's functions approach is theoretically well-established in many-body theory, but to our knowledge, no actual application to nuclear systems has been previously published. It has a number of desirable properties, foremost the gently scaling with system size compared to direct diagonalization and the closeness to experimentally accessible quantities. The main drawback is the numerical instabilities due to the pole structure of the one-particle propagator, leading to convergence difficulties. This issue is one of the main focal points of the work presented in this thesis, and strategies to improve the convergence properties are described and investigated. We have applied the method both to a simple model which can be solved by exact diagonalization and to the more realistic 4 He system. The results shows that our implementation is close to the exact solution in the simple model as long as the interaction strengths are small. As the number of particles increases, convergence is increasingly hard to obtain. In the 4 He case, we obtain results in the vicinity of the results from comparable approaches. The numerical in-stabilities in the current implementation still prevents the desired accuracy and stability necessary to achieve the current benchmark standards. (Author)
Diagnostic accuracy in virtual dermatopathology
DEFF Research Database (Denmark)
Mooney, E.; Kempf, W.; Jemec, G.B.E.
2012-01-01
Background Virtual microscopy is used for teaching medical students and residents and for in-training and certification examinations in the United States. However, no existing studies compare diagnostic accuracy using virtual slides and photomicrographs. The objective of this study was to compare...... diagnostic accuracy of dermatopathologists and pathologists using photomicrographs vs. digitized images, through a self-assessment examination, and to elucidate assessment of virtual dermatopathology. Methods Forty-five dermatopathologists and pathologists received a randomized combination of 15 virtual...... slides and photomicrographs with corresponding clinical photographs and information in a self-assessment examination format. Descriptive data analysis and comparison of groups were performed using a chi-square test. Results Diagnostic accuracy in dermatopathology using virtual dermatopathology...
A realistic model for quantum theory with a locality property
International Nuclear Information System (INIS)
Eberhard, P.H.
1987-04-01
A model reproducing the predictions of relativistic quantum theory to any desired degree of accuracy is described in this paper. It involves quantities that are independent of the observer's knowledge, and therefore can be called real, and which are defined at each point in space, and therefore can be called local in a rudimentary sense. It involves faster-than-light, but not instantaneous, action at distance
Dean, Kevin M.; Babayco, Christopher B.; Sluss, Daniel R. B.; Williamson, J. Charles
2010-08-01
The synthetic-method determination of liquid-liquid coexistence curves using semiautomated light scattering instrumentation and stirred samples is based on identifying the coexistence curve transition temperatures (Tcx) from sudden changes in turbidity associated with droplet formation. Here we use a thorough set of such measurements to evaluate the accuracy of several different analysis methods reported in the literature for assigning Tcx. More than 20 samples each of weakly opalescent isobutyric acid+water and strongly opalescent aniline+hexane were tested with our instrumentation. Transmitted light and scattering intensities at 2°, 24°, and 90° were collected simultaneously as a function of temperature for each stirred sample, and the data were compared with visual observations and light scattering theory. We find that assigning Tcx to the onset of decreased transmitted light or increased 2° scattering has a potential accuracy of 0.01 K or better for many samples. However, the turbidity due to critical opalescence obscures the identification of Tcx from the light scattering data of near-critical stirred samples, and no simple rule of interpretation can be applied regardless of collection geometry. At best, when 90° scattering is collected along with transmitted or 2° data, the accuracy of Tcx is limited to 0.05 K for near-critical samples. Visual determination of Tcx remains the more accurate approach in this case.
Accuracy of ab initio electron correlation and electron densities in vanadium dioxide
Kylänpää, Ilkka; Balachandran, Janakiraman; Ganesh, Panchapakesan; Heinonen, Olle; Kent, Paul R. C.; Krogel, Jaron T.
2017-11-01
Diffusion quantum Monte Carlo results are used as a reference to analyze properties related to phase stability and magnetism in vanadium dioxide computed with various formulations of density functional theory. We introduce metrics related to energetics, electron densities and spin densities that give us insight on both local and global variations in the antiferromagnetic M1 and R phases. Importantly, these metrics can address contributions arising from the challenging description of the 3 d orbital physics in this material. We observe that the best description of energetics between the structural phases does not correspond to the best accuracy in the charge density, which is consistent with observations made recently by Medvedev et al. [Science 355, 371 (2017), 10.1126/science.aag0410] in the context of isolated atoms. However, we do find evidence that an accurate spin density connects to correct energetic ordering of different magnetic states in VO2, although local, semilocal, and meta-GGA functionals tend to erroneously favor demagnetization of the vanadium sites. The recently developed SCAN functional stands out as remaining nearly balanced in terms of magnetization across the M1-R transition and correctly predicting the ground state crystal structure. In addition to ranking current density functionals, our reference energies and densities serve as important benchmarks for future functional development. With our reference data, the accuracy of both the energy and the electron density can be monitored simultaneously, which is useful for functional development. So far, this kind of detailed high accuracy reference data for correlated materials has been absent from the literature.
Status of effective field theory of NN scattering
International Nuclear Information System (INIS)
Beane, S.R.
1998-06-01
There exist many nucleon-nucleon potentials which reproduce phase shifts and nuclear properties with remarkable accuracy. Three fundamental features are shared by these potential models: (1) pions are important at long distances, (2) there is a source of intermediate-range attraction, and (3) there is a source of short-distance repulsion. However, in general, distinct physical mechanisms in these models account for the same feature of the nuclear force. Agreement with experiment is maintained in spite of these differences because of the large number of fit parameters. Systematic approaches to the scattering of strongly interacting particles, such as chiral perturbation theory, are based on the ideas of effective field theory (EFT). The author reviews recent progress in developing a systematic power counting scheme for scattering processes involving more than one nucleon
Cystic Duct Closure by Sealing With Bipolar Electrocoagulation
Damgaard, B.; Jorgensen, L. N.; Larsen, S. S.; Kristiansen, V. B.
2010-01-01
Background: Cystic duct leakage after cholecystectomy is not uncommon and is a potentially serious complication. The aim of this study was to assess a bipolar sealing system (LigaSure®) for closure of the cystic duct. Methods: The records from consecutive laparoscopic cholecystectomies performed in 2 hospitals with closure of the cystic duct with LigaSure after informed consent were recorded and complications and morbidity registered. The records were compared with those of patients undergoing laparoscopic cholecystectomy with closure of the cystic duct with clips during the same period. Results: During the study period, 218 laparoscopic cholecystectomies were performed; 102 of these were performed with the LigaSure. One patient was excluded due to violation of the protocol. We experienced no cases of cystic duct leakage, but in one patient, bile leakage from the gallbladder bed was observed probably due to a small aberrant duct. Conclusion: The LigaSure system was safe and effective for closure and division of the cystic duct in laparoscopic cholecystectomy. PMID:20412641
International Nuclear Information System (INIS)
Choi, Sunghwan; Hong, Kwangwoo; Kim, Jaewook; Kim, Woo Youn
2015-01-01
We developed a self-consistent field program based on Kohn-Sham density functional theory using Lagrange-sinc functions as a basis set and examined its numerical accuracy for atoms and molecules through comparison with the results of Gaussian basis sets. The result of the Kohn-Sham inversion formula from the Lagrange-sinc basis set manifests that the pseudopotential method is essential for cost-effective calculations. The Lagrange-sinc basis set shows faster convergence of the kinetic and correlation energies of benzene as its size increases than the finite difference method does, though both share the same uniform grid. Using a scaling factor smaller than or equal to 0.226 bohr and pseudopotentials with nonlinear core correction, its accuracy for the atomization energies of the G2-1 set is comparable to all-electron complete basis set limits (mean absolute deviation ≤1 kcal/mol). The same basis set also shows small mean absolute deviations in the ionization energies, electron affinities, and static polarizabilities of atoms in the G2-1 set. In particular, the Lagrange-sinc basis set shows high accuracy with rapid convergence in describing density or orbital changes by an external electric field. Moreover, the Lagrange-sinc basis set can readily improve its accuracy toward a complete basis set limit by simply decreasing the scaling factor regardless of systems
Directory of Open Access Journals (Sweden)
Ricardo Vinícius de Melo Leite
2009-12-01
Full Text Available As ligas metálicas aplicadas por soldagem em superfícies, objetivando a proteção contra o desgaste e o conseqüente aumento da vida útil de peças e equipamentos, têm sido utilizadas em larga escala nas indústrias de bens de consumo e nos setores de mineração e sucroalcooleiro. O desgaste abrasivo em peças e equipamentos representa, nestas industriais, um dos principais fatores de depreciação de capital e uma importante fonte de despesas com manutenção. Para a aplicação do revestimento por soldagem, os arames tubulares têm sido uma alternativa cada vez mais viável, devido à sua alta produtividade e qualidade de solda, substituindo, em parte, o uso do eletrodo revestido. O objetivo deste trabalho é fazer um estudo comparativo da resistência ao desgaste abrasivo do revestimento aplicado por soldagem com arames tubulares autoprotegidos de três ligas metálicas utilizadas na indústria, uma do tipo Fe-Cr-C, outra do tipo Fe-Cr-C com adição de nióbio e boro e a terceira, do tipo Fe-Cr-C com adição de nióbio. Os revestimentos anti-desgaste, conhecidos como revestimento duro, foram aplicados em chapas de aço carbono, com os mesmos parâmetros e procedimentos de soldagem. Os corpos de prova foram obtidos por corte e retificação e foram submetidos a ensaios de desgaste abrasivo, em um abrasômero Roda de Borracha, conforme procedimento estabelecido pela norma ASTM G65-91. Os resultados obtidos demonstraram que a liga Fe-Cr-C com adição de Nióbio e Boro apresentou desempenho superior em relação ao desgaste abrasivo.The metal alloys deposited by welding on the components surface, with the objective of protection against wear and the consequent increase in the lifetime of parts and equipments, have been used extensively in the consumer products industry and sectors of Mining and Sugar & alcohol. The abrasive wear on parts and equipments represents one of the main depreciation factors of capital and the major source of
Continuum orbital approximations in weak-coupling theories for inelastic electron scattering
International Nuclear Information System (INIS)
Peek, J.M.; Mann, J.B.
1977-01-01
Two approximations, motivated by heavy-particle scattering theory, are tested for weak-coupling electron-atom (ion) inelastic scattering theory. They consist of replacing the one-electron scattering orbitals by their Langer uniform approximations and the use of an average trajectory approximation which entirely avoids the necessity for generating continuum orbitals. Numerical tests for a dipole-allowed and a dipole-forbidden event, based on Coulomb-Born theory with exchange neglected, reveal the error trends. It is concluded that the uniform approximation gives a satisfactory prediction for traditional weak-coupling theories while the average approximation should be limited to collision energies exceeding at least twice the threshold energy. The accuracy for both approximations is higher for positive ions than for neutral targets. Partial-wave collision-strength data indicate that greater care should be exercised in using these approximations to predict quantities differential in the scattering angle. An application to the 2s 2 S-2p 2 P transition in Ne VIII is presented
Scattering amplitudes in four- and six-dimensional gauge theories
International Nuclear Information System (INIS)
Schuster, Theodor
2014-01-01
We study scattering amplitudes in quantum chromodynamics (QCD), N=4 super Yang-Mills (SYM) theory and the six-dimensional N=(1,1) SYM theory, focusing on the symmetries of and relations between the tree-level scattering amplitudes in these three gauge theories. We derive the tree level and one-loop color decomposition of an arbitrary QCD amplitude into primitive amplitudes. Furthermore, we derive identities spanning the null space among the primitive amplitudes. We prove that every color ordered tree amplitude of massless QCD can be obtained from gluon-gluino amplitudes of N=4 SYM theory. Furthermore, we derive analytical formulae for all gluon-gluino amplitudes relevant for QCD. We compare the numerical efficiency and accuracy of evaluating these closed analytic formulae for color ordered QCD tree amplitudes to a numerically efficient implementation of the Berends-Giele recursion. We derive the symmetries of massive tree amplitudes on the coulomb branch of N=4 SYM theory, which in turn can be obtained from N=(1,1) SYM theory by dimensional reduction. Furthermore, we investigate the tree amplitudes of N=(1, 1) SYM theory and explain how analytical formulae can be obtained from a numerical implementation of the supersymmetric BCFW recursion relation and investigate a potential uplift of the massless tree amplitudes of N=4 SYM theory. Finally we study an alternative to dimensional regularization of N=4 SYM theory. The infrared divergences are regulated by masses obtained from a Higgs mechanism. The corresponding string theory set-up suggests that the amplitudes have an exact dual conformal symmetry. We confirm this expectation and illustrate the calculational advantages of the massive regulator by explicit calculations.
Directory of Open Access Journals (Sweden)
Qu Li
2014-01-01
Full Text Available Online friend recommendation is a fast developing topic in web mining. In this paper, we used SVD matrix factorization to model user and item feature vector and used stochastic gradient descent to amend parameter and improve accuracy. To tackle cold start problem and data sparsity, we used KNN model to influence user feature vector. At the same time, we used graph theory to partition communities with fairly low time and space complexity. What is more, matrix factorization can combine online and offline recommendation. Experiments showed that the hybrid recommendation algorithm is able to recommend online friends with good accuracy.
Multiple scattering theory for space filling potentials
International Nuclear Information System (INIS)
Butler, W.H.; Brown, R.G.; Nesbet, R.K.
1990-01-01
Multiple scattering theory (MST) provides an efficient technique for solving the wave equation for the special case of muffin-tin potentials. Here MST is extended to treat space filling non-muffin tin potentials and its validity, accuracy and efficiency are tested by application of the two dimensional empty lattice test. For this test it is found that the traditional formulation of MST does not coverage as the number of partial waves is increased. A simple modification of MST, however, allows this problem to be solved exactly and efficiently. 15 refs., 3 tabs
A Refined Zigzag Beam Theory for Composite and Sandwich Beams
Tessler, Alexander; Sciuva, Marco Di; Gherlone, Marco
2009-01-01
A new refined theory for laminated composite and sandwich beams that contains the kinematics of the Timoshenko Beam Theory as a proper baseline subset is presented. This variationally consistent theory is derived from the virtual work principle and employs a novel piecewise linear zigzag function that provides a more realistic representation of the deformation states of transverse-shear flexible beams than other similar theories. This new zigzag function is unique in that it vanishes at the top and bottom bounding surfaces of a beam. The formulation does not enforce continuity of the transverse shear stress across the beam s cross-section, yet is robust. Two major shortcomings that are inherent in the previous zigzag theories, shear-force inconsistency and difficulties in simulating clamped boundary conditions, and that have greatly limited the utility of these previous theories are discussed in detail. An approach that has successfully resolved these shortcomings is presented herein. Exact solutions for simply supported and cantilevered beams subjected to static loads are derived and the improved modelling capability of the new zigzag beam theory is demonstrated. In particular, extensive results for thick beams with highly heterogeneous material lay-ups are discussed and compared with corresponding results obtained from elasticity solutions, two other zigzag theories, and high-fidelity finite element analyses. Comparisons with the baseline Timoshenko Beam Theory are also presented. The comparisons clearly show the improved accuracy of the new, refined zigzag theory presented herein over similar existing theories. This new theory can be readily extended to plate and shell structures, and should be useful for obtaining relatively low-cost, accurate estimates of structural response needed to design an important class of high-performance aerospace structures.
Accuracy and precision in thermoluminescence dosimetry
International Nuclear Information System (INIS)
Marshall, T.O.
1984-01-01
The question of accuracy and precision in thermoluminescent dosimetry, particularly in relation to lithium fluoride phosphor, is discussed. The more important sources of error, including those due to the detectors, the reader, annealing and dosemeter design, are identified and methods of reducing their effects on accuracy and precision to a minimum are given. Finally, the accuracy and precision achievable for three quite different applications are discussed, namely, for personal dosimetry, environmental monitoring and for the measurement of photon dose distributions in phantoms. (U.K.)
No special K! A signal detection framework for the strategic regulation of memory accuracy.
Higham, Philip A
2007-02-01
Two experiments investigated criterion setting and metacognitive processes underlying the strategic regulation of accuracy on the Scholastic Aptitude Test (SAT) using Type-2 signal detection theory (SDT). In Experiment 1, report bias was manipulated by penalizing participants either 0.25 (low incentive) or 4 (high incentive) points for each error. Best guesses to unanswered items were obtained so that Type-2 signal detection indices of discrimination and bias could be calculated. The same incentive manipulation was used in Experiment 2, only the test was computerized, confidence ratings were taken so that receiver operating characteristic (ROC) curves could be generated, and feedback was manipulated. The results of both experiments demonstrated that SDT provides a viable alternative to A. Koriat and M. Goldsmith's (1996c) framework of monitoring and control and reveals information about the regulation of accuracy that their framework does not. For example, ROC analysis indicated that the threshold model implied by formula scoring is inadequate. Instead, performance on the SAT should be modeled with an equal-variance Gaussian, Type-2 signal detection model. ((c) 2007 APA, all rights reserved).
Experimental verification of the gas pumping theory within fission ionisation chambers
International Nuclear Information System (INIS)
Bartlett, A.C.
1975-01-01
Experimental verification of a theory for gas loss from in-core ionization chambers is reported. A value of the gas pressure within an irradiated miniature fission chamber was derived indirectly by use of published data on Townsend first coefficient/field across the detector as a function of field/pressure. In practice the voltage corresponding to 10% current multiplication is measured. From the current saturation characteristics measured on the detector during irradiation, the change in gas pressure as a function of fluence was derived and compared to theoretically predicted values. Within the limited accuracy obtainable substantial agreement between measurement and theory is obtained. (O.T.)
International Nuclear Information System (INIS)
Buchbinder, I.L.; Odintsov, S.D.; Lichtzier, I.M.
1989-01-01
The question of the behaviour of effective coupling constants in one-loop 'finite' grand unification theories in curved spacetime is investigated. It is shown that in strong gravitational fields the effective coupling constant, corresponding to the parameter of non-minimal interaction of scalar and gravitational fields, tends to the conformal value or increases in an exponential fashion. The one-loop effective potential is obtained with accuracy to linear curvature terms. It is shown that, in external supergravity, supersymmetric finite theories admit asymptotic conformal invariance. (Author)
Cadastral Database Positional Accuracy Improvement
Hashim, N. M.; Omar, A. H.; Ramli, S. N. M.; Omar, K. M.; Din, N.
2017-10-01
Positional Accuracy Improvement (PAI) is the refining process of the geometry feature in a geospatial dataset to improve its actual position. This actual position relates to the absolute position in specific coordinate system and the relation to the neighborhood features. With the growth of spatial based technology especially Geographical Information System (GIS) and Global Navigation Satellite System (GNSS), the PAI campaign is inevitable especially to the legacy cadastral database. Integration of legacy dataset and higher accuracy dataset like GNSS observation is a potential solution for improving the legacy dataset. However, by merely integrating both datasets will lead to a distortion of the relative geometry. The improved dataset should be further treated to minimize inherent errors and fitting to the new accurate dataset. The main focus of this study is to describe a method of angular based Least Square Adjustment (LSA) for PAI process of legacy dataset. The existing high accuracy dataset known as National Digital Cadastral Database (NDCDB) is then used as bench mark to validate the results. It was found that the propose technique is highly possible for positional accuracy improvement of legacy spatial datasets.
Rodrigo Tiossi
2006-01-01
O objetivo deste estudo foi avaliar o assentamento passivo de supra-estruturas de próteses fixas implanto-suportadas de três elementos, fundidas em titânio comercialmente puro e em ligas à base de Ni-Cr e Co-Cr. Para esta análise foi utilizado o método de Sheffield (EISENMAN, 1997), e as leituras foram realizadas num microscópio óptico comparador (Nikon, Japão). Foram utilizados dois implantes de hexágono interno Master Conect AR (Conexão Sistemas de Prótese, Brasil). Os dados foram submetido...
International Nuclear Information System (INIS)
Du, Ping; Lin, I-Kuan; Zhang, Xin; Lu, Hongbing
2010-01-01
Polydimethylsiloxane (PDMS)-based micropillars (or microcantilevers) have been used as bio-transducers for measuring cellular forces on the order of pN to µN. The measurement accuracy of these sensitive devices depends on appropriate modeling to convert the micropillar deformations into the corresponding reaction forces. The traditional approach to calculating the reaction force is based on the Euler beam theory with consideration of a linear elastic slender beam for the micropillar. However, the low aspect ratio in geometry of PDMS micropillars does not satisfy the slender beam requirement. Consequently, the Timoshenko beam theory, appropriate for a beam with a low aspect ratio, should be used. In addition, the inherently time-dependent behavior in PDMS has to be considered for accurate force conversion. In this paper, the Timoshenko beam theory, along with the consideration of viscoelastic behavior of PDMS, was used to model the mechanical response of micropillars. The viscoelastic behavior of PDMS was characterized by stress relaxation nanoindentation using a circular flat punch. A correction procedure was developed to determine the load–displacement relationship with consideration of ramp loading. The relaxation function was extracted and described by a generalized Maxwell model. The bending of rectangular micropillars was performed by a wedge indenter tip. The viscoelastic Timoshenko beam formula was used to calculate the mechanical response of the micropillar, and the results were compared with measurement data. The calculated reaction forces agreed well with the experimental data at three different loading rates. A parametric study was conducted to evaluate the accuracy of the viscoelastic Timoshenko beam model by comparing the reaction forces calculated from the elastic Euler beam, elastic Timoshenko beam and viscoelastic Euler beam models at various aspect ratios and loading rates. The extension of modeling from the elastic Euler beam theory to the
International Nuclear Information System (INIS)
Barnes, T.; Daniell, G.J.
1982-09-01
A finite lattice technique is introduced for calculating the spectrum of fluctuating Bose theories in the continuum limit. The method gives the continuum spectrum to an estimated approximately 1% accuracy in (1+1) dimensions using available computer memory. The spectrum of lambda phi 4 theory in (1+1) dimensions is studied as a trial application; results are found consistent with a free theory spectrum. (author)
Outline of a classical theory of quantum physics and gravitation
International Nuclear Information System (INIS)
Gallop, J.W.
1975-01-01
It is argued that in the manner in which the Galilean-Newtonian physics may be said to have explained the Ptolemaic-Copernican theories in terms which have since been called classical, so also Milner's theories of the structure of matter may be said to explain present day quantum and relativistic theory. In both cases the former employ the concept of force and the latter, by contrast, are geometrical theories. Milner envisaged space as being stressed, whereas Einstein thought of it as strained. Development of Milner's theory from criticisms and suggestions made by Kilmister has taken it further into the realms of quantum and gravitational physics, where it is found to give a more physically comprehensible explanation of the phenomena. Further, it shows why present day quantum theory is cast in a statistical form. The theory is supported by many predictions such as the ratio of Planck's constant to the mass of the electron, the value of the fine structure constant and reason for apparent variations in past measurements, the magnetic moment of the electron and proton of the stable particles such as the neutron Λ and Σ together with the kaon, and a relation between the universal gravitational constant and Hubble's constant - all within published experimental accuracy. The latest results to be accounted for by the theory are the masses of the newly discovered psi particles and confirmation of the value of the decay of Newton's gravitational constant obtained from lunar measurements. (author)
Cognitive Hierarchy Theory and Two-Person Games
Directory of Open Access Journals (Sweden)
Carlos Gracia-Lázaro
2017-01-01
Full Text Available The outcome of many social and economic interactions, such as stock-market transactions, is strongly determined by the predictions that agents make about the behavior of other individuals. Cognitive hierarchy theory provides a framework to model the consequences of forecasting accuracy that has proven to fit data from certain types of game theory experiments, such as Keynesian beauty contests and entry games. Here, we focus on symmetric two-player-two-action games and establish an algorithm to find the players’ strategies according to the cognitive hierarchy approach. We show that the snowdrift game exhibits a pattern of behavior whose complexity grows as the cognitive levels of players increases. In addition to finding the solutions up to the third cognitive level, we demonstrate, in this theoretical frame, two new properties of snowdrift games: (i any snowdrift game can be characterized by only a parameter, its class; (ii they are anti-symmetric with respect to the diagonal of the pay-off’s space. Finally, we propose a model based on an evolutionary dynamics that captures the main features of the cognitive hierarchy theory.
Anxiety, anticipation and contextual information: A test of attentional control theory.
Cocks, Adam J; Jackson, Robin C; Bishop, Daniel T; Williams, A Mark
2016-09-01
We tested the assumptions of Attentional Control Theory (ACT) by examining the impact of anxiety on anticipation using a dynamic, time-constrained task. Moreover, we examined the involvement of high- and low-level cognitive processes in anticipation and how their importance may interact with anxiety. Skilled and less-skilled tennis players anticipated the shots of opponents under low- and high-anxiety conditions. Participants viewed three types of video stimuli, each depicting different levels of contextual information. Performance effectiveness (response accuracy) and processing efficiency (response accuracy divided by corresponding mental effort) were measured. Skilled players recorded higher levels of response accuracy and processing efficiency compared to less-skilled counterparts. Processing efficiency significantly decreased under high- compared to low-anxiety conditions. No difference in response accuracy was observed. When reviewing directional errors, anxiety was most detrimental to performance in the condition conveying only contextual information, suggesting that anxiety may have a greater impact on high-level (top-down) cognitive processes, potentially due to a shift in attentional control. Our findings provide partial support for ACT; anxiety elicited greater decrements in processing efficiency than performance effectiveness, possibly due to predominance of the stimulus-driven attentional system.
Directory of Open Access Journals (Sweden)
MIHAELA BRATU (SIMIONESCU
2012-12-01
Full Text Available In this study some alternative forecasts for the unemployment rate of USA made by four institutions (International Monetary Fund (IMF, Organization for Economic Co-operation and Development (OECD, Congressional Budget Office (CBO and Blue Chips (BC are evaluated regarding the accuracy and the biasness. The most accurate predictions on the forecasting horizon 201-2011 were provided by IMF, followed by OECD, CBO and BC.. These results were gotten using U1 Theil’s statistic and a new method that has not been used before in literature in this context. The multi-criteria ranking was applied to make a hierarchy of the institutions regarding the accuracy and five important accuracy measures were taken into account at the same time: mean errors, mean squared error, root mean squared error, U1 and U2 statistics of Theil. The IMF, OECD and CBO predictions are unbiased. The combined forecasts of institutions’ predictions are a suitable strategy to improve the forecasts accuracy of IMF and OECD forecasts when all combination schemes are used, but INV one is the best. The filtered and smoothed original predictions based on Hodrick-Prescott filter, respectively Holt-Winters technique are a good strategy of improving only the BC expectations. The proposed strategies to improve the accuracy do not solve the problem of biasness. The assessment and improvement of forecasts accuracy have an important contribution in growing the quality of decisional process.
Accuracy Assessment of Different Digital Surface Models
Directory of Open Access Journals (Sweden)
Ugur Alganci
2018-03-01
Full Text Available Digital elevation models (DEMs, which can occur in the form of digital surface models (DSMs or digital terrain models (DTMs, are widely used as important geospatial information sources for various remote sensing applications, including the precise orthorectification of high-resolution satellite images, 3D spatial analyses, multi-criteria decision support systems, and deformation monitoring. The accuracy of DEMs has direct impacts on specific calculations and process chains; therefore, it is important to select the most appropriate DEM by considering the aim, accuracy requirement, and scale of each study. In this research, DSMs obtained from a variety of satellite sensors were compared to analyze their accuracy and performance. For this purpose, freely available Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER 30 m, Shuttle Radar Topography Mission (SRTM 30 m, and Advanced Land Observing Satellite (ALOS 30 m resolution DSM data were obtained. Additionally, 3 m and 1 m resolution DSMs were produced from tri-stereo images from the SPOT 6 and Pleiades high-resolution (PHR 1A satellites, respectively. Elevation reference data provided by the General Command of Mapping, the national mapping agency of Turkey—produced from 30 cm spatial resolution stereo aerial photos, with a 5 m grid spacing and ±3 m or better overall vertical accuracy at the 90% confidence interval (CI—were used to perform accuracy assessments. Gross errors and water surfaces were removed from the reference DSM. The relative accuracies of the different DSMs were tested using a different number of checkpoints determined by different methods. In the first method, 25 checkpoints were selected from bare lands to evaluate the accuracies of the DSMs on terrain surfaces. In the second method, 1000 randomly selected checkpoints were used to evaluate the methods’ accuracies for the whole study area. In addition to the control point approach, vertical cross
Should the model for risk-informed regulation be game theory rather than decision theory?
Bier, Vicki M; Lin, Shi-Woei
2013-02-01
Risk analysts frequently view the regulation of risks as being largely a matter of decision theory. According to this view, risk analysis methods provide information on the likelihood and severity of various possible outcomes; this information should then be assessed using a decision-theoretic approach (such as cost/benefit analysis) to determine whether the risks are acceptable, and whether additional regulation is warranted. However, this view ignores the fact that in many industries (particularly industries that are technologically sophisticated and employ specialized risk and safety experts), risk analyses may be done by regulated firms, not by the regulator. Moreover, those firms may have more knowledge about the levels of safety at their own facilities than the regulator does. This creates a situation in which the regulated firm has both the opportunity-and often also the motive-to provide inaccurate (in particular, favorably biased) risk information to the regulator, and hence the regulator has reason to doubt the accuracy of the risk information provided by regulated parties. Researchers have argued that decision theory is capable of dealing with many such strategic interactions as well as game theory can. This is especially true in two-player, two-stage games in which the follower has a unique best strategy in response to the leader's strategy, as appears to be the case in the situation analyzed in this article. However, even in such cases, we agree with Cox that game-theoretic methods and concepts can still be useful. In particular, the tools of mechanism design, and especially the revelation principle, can simplify the analysis of such games because the revelation principle provides rigorous assurance that it is sufficient to analyze only games in which licensees truthfully report their risk levels, making the problem more manageable. Without that, it would generally be necessary to consider much more complicated forms of strategic behavior (including
Seitz, Holli H; Gibson, Laura; Skubisz, Christine; Forquer, Heather; Mello, Susan; Schapira, Marilyn M; Armstrong, Katrina; Cappella, Joseph N
2016-10-01
This experiment tested the effects of an individualized risk-based online mammography decision intervention. The intervention employs exemplification theory and the Elaboration Likelihood Model of persuasion to improve the match between breast cancer risk and mammography intentions. 2918 women ages 35-49 were stratified into two levels of 10-year breast cancer risk (<1.5%; ≥1.5%) then randomly assigned to one of eight conditions: two comparison conditions and six risk-based intervention conditions that varied according to a 2 (amount of content: brief vs. extended) x 3 (format: expository vs. untailored exemplar [example case] vs. tailored exemplar) design. Outcomes included mammography intentions and accuracy of perceived breast cancer risk. Risk-based intervention conditions improved the match between objective risk estimates and perceived risk, especially for high-numeracy women with a 10-year breast cancer risk ≤1.5%. For women with a risk≤1.5%, exemplars improved accuracy of perceived risk and all risk-based interventions increased intentions to wait until age 50 to screen. A risk-based mammography intervention improved accuracy of perceived risk and the match between objective risk estimates and mammography intentions. Interventions could be applied in online or clinical settings to help women understand risk and make mammography decisions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Accuracy and reliability of peer assessment of athletic training psychomotor laboratory skills.
Marty, Melissa C; Henning, Jolene M; Willse, John T
2010-01-01
Peer assessment is defined as students judging the level or quality of a fellow student's understanding. No researchers have yet demonstrated the accuracy or reliability of peer assessment in athletic training education. To determine the accuracy and reliability of peer assessment of athletic training students' psychomotor skills. Cross-sectional study. Entry-level master's athletic training education program. First-year (n = 5) and second-year (n = 8) students. Participants evaluated 10 videos of a peer performing 3 psychomotor skills (middle deltoid manual muscle test, Faber test, and Slocum drawer test) on 2 separate occasions using a valid assessment tool. Accuracy of each peer-assessment score was examined through percentage correct scores. We used a generalizability study to determine how reliable athletic training students were in assessing a peer performing the aforementioned skills. Decision studies using generalizability theory demonstrated how the peer-assessment scores were affected by the number of participants and number of occasions. Participants had a high percentage of correct scores: 96.84% for the middle deltoid manual muscle test, 94.83% for the Faber test, and 97.13% for the Slocum drawer test. They were not able to reliably assess a peer performing any of the psychomotor skills on only 1 occasion. However, the φ increased (exceeding the 0.70 minimal standard) when 2 participants assessed the skill on 3 occasions (φ = 0.79) for the Faber test, with 1 participant on 2 occasions (φ = 0.76) for the Slocum drawer test, and with 3 participants on 2 occasions for the middle deltoid manual muscle test (φ = 0.72). Although students did not detect all errors, they assessed their peers with an average of 96% accuracy. Having only 1 student assess a peer performing certain psychomotor skills was less reliable than having more than 1 student assess those skills on more than 1 occasion. Peer assessment of psychomotor skills
Improving coding accuracy in an academic practice.
Nguyen, Dana; O'Mara, Heather; Powell, Robert
2017-01-01
Practice management has become an increasingly important component of graduate medical education. This applies to every practice environment; private, academic, and military. One of the most critical aspects of practice management is documentation and coding for physician services, as they directly affect the financial success of any practice. Our quality improvement project aimed to implement a new and innovative method for teaching billing and coding in a longitudinal fashion in a family medicine residency. We hypothesized that implementation of a new teaching strategy would increase coding accuracy rates among residents and faculty. Design: single group, pretest-posttest. military family medicine residency clinic. Study populations: 7 faculty physicians and 18 resident physicians participated as learners in the project. Educational intervention: monthly structured coding learning sessions in the academic curriculum that involved learner-presented cases, small group case review, and large group discussion. overall coding accuracy (compliance) percentage and coding accuracy per year group for the subjects that were able to participate longitudinally. Statistical tests used: average coding accuracy for population; paired t test to assess improvement between 2 intervention periods, both aggregate and by year group. Overall coding accuracy rates remained stable over the course of time regardless of the modality of the educational intervention. A paired t test was conducted to compare coding accuracy rates at baseline (mean (M)=26.4%, SD=10%) to accuracy rates after all educational interventions were complete (M=26.8%, SD=12%); t24=-0.127, P=.90. Didactic teaching and small group discussion sessions did not improve overall coding accuracy in a residency practice. Future interventions could focus on educating providers at the individual level.
Experimental test of General Relativity theory by radar observations of planets
International Nuclear Information System (INIS)
Afanas'eva, T.I.; Kislik, M.D.; Kolyuka, Yu.F.; Tikhonov, V.F.
1991-01-01
Basing on the radar observations of planets, carried out in the USSR and USA in 1964-1986, a particular relativistic effect has been tested, namely the (O-C) discrepancies in radar distances, arising in the construction of a unified theory of motion on interior planets in the Newtonian approximation. The results obtained confirm the validity of General Relativity to an accuracy of about 10 -2
Improving Machining Accuracy of CNC Machines with Innovative Design Methods
Yemelyanov, N. V.; Yemelyanova, I. V.; Zubenko, V. L.
2018-03-01
The article considers achieving the machining accuracy of CNC machines by applying innovative methods in modelling and design of machining systems, drives and machine processes. The topological method of analysis involves visualizing the system as matrices of block graphs with a varying degree of detail between the upper and lower hierarchy levels. This approach combines the advantages of graph theory and the efficiency of decomposition methods, it also has visual clarity, which is inherent in both topological models and structural matrices, as well as the resiliency of linear algebra as part of the matrix-based research. The focus of the study is on the design of automated machine workstations, systems, machines and units, which can be broken into interrelated parts and presented as algebraic, topological and set-theoretical models. Every model can be transformed into a model of another type, and, as a result, can be interpreted as a system of linear and non-linear equations which solutions determine the system parameters. This paper analyses the dynamic parameters of the 1716PF4 machine at the stages of design and exploitation. Having researched the impact of the system dynamics on the component quality, the authors have developed a range of practical recommendations which have enabled one to reduce considerably the amplitude of relative motion, exclude some resonance zones within the spindle speed range of 0...6000 min-1 and improve machining accuracy.
Density functional theory: Foundations reviewed
Energy Technology Data Exchange (ETDEWEB)
Kryachko, Eugene S., E-mail: eugene.kryachko@ulg.ac.be [Bogolyubov Institute for Theoretical Physics, Kiev, 03680 (Ukraine); Ludeña, Eduardo V., E-mail: popluabe@yahoo.es [Centro de Química, Instituto Venezolano de Investigaciones Científicas, IVIC, Apartado 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of); Prometheus Program, Senescyt (Ecuador); Grupo Ecuatoriano para el Estudio Experimental y Teórico de Nanosistemas, GETNano, USFQ, N104-E, Quito (Ecuador); Escuela Politécnica Superior del Litoral, ESPOL, Guayaquil (Ecuador)
2014-11-10
-geared functionals. These problems are discussed by making reference to ab initio DFT as well as to the local-scaling-transformation version of DFT, LS-DFT. In addition, we examine the question of the accuracy of approximate exchange–correlation functionals in the light of their non-observance of the variational principle. Why do approximate functionals yield reasonable (and accurate) descriptions of many molecular and condensed matter properties? Are the conditions imposed on exchange and correlation functionals sufficiently adequate to produce accurate semi-empirical functionals? In this respect, we consider the question of whether the results reflect a true approach to chemical accuracy or are just the outcome of a virtuoso-like performance which cannot be systematically improved. We discuss the issue of the accuracy of the contemporary DFT results by contrasting them to those obtained by the alternative RDMT and NOFT. We discuss the possibility of improving DFT functionals by applying in a systematic way the N-representability conditions on the 2-RDM. In this respect, we emphasize the possibility of constructing 2-matrices in the context of the local scaling transformation version of DFT to which the N-representability condition of RDM theory may be applied. We end up our revision of HKS-DFT by considering some of the problems related to spin symmetry and discuss some current issues dealing with a proper treatment of open-shell systems. We are particularly concerned, as in the rest of this paper, mostly with foundational issues arising in the construction of functionals. We dedicate the whole Section 4 to the local-scaling transformation version of density functional theory, LS-DFT. The reason is that in this theory some of the fundamental problems that appear in HKS-DFT, have been solved. For example, in LS-DFT the functionals are, in principle, designed to fulfill v- and N-representability conditions from the outset. This is possible because LS-DFT is based on density
Multiple sequence alignment accuracy and phylogenetic inference.
Ogden, T Heath; Rosenberg, Michael S
2006-04-01
Phylogenies are often thought to be more dependent upon the specifics of the sequence alignment rather than on the method of reconstruction. Simulation of sequences containing insertion and deletion events was performed in order to determine the role that alignment accuracy plays during phylogenetic inference. Data sets were simulated for pectinate, balanced, and random tree shapes under different conditions (ultrametric equal branch length, ultrametric random branch length, nonultrametric random branch length). Comparisons between hypothesized alignments and true alignments enabled determination of two measures of alignment accuracy, that of the total data set and that of individual branches. In general, our results indicate that as alignment error increases, topological accuracy decreases. This trend was much more pronounced for data sets derived from more pectinate topologies. In contrast, for balanced, ultrametric, equal branch length tree shapes, alignment inaccuracy had little average effect on tree reconstruction. These conclusions are based on average trends of many analyses under different conditions, and any one specific analysis, independent of the alignment accuracy, may recover very accurate or inaccurate topologies. Maximum likelihood and Bayesian, in general, outperformed neighbor joining and maximum parsimony in terms of tree reconstruction accuracy. Results also indicated that as the length of the branch and of the neighboring branches increase, alignment accuracy decreases, and the length of the neighboring branches is the major factor in topological accuracy. Thus, multiple-sequence alignment can be an important factor in downstream effects on topological reconstruction.
Accuracy Limitations in Optical Linear Algebra Processors
Batsell, Stephen Gordon
1990-01-01
One of the limiting factors in applying optical linear algebra processors (OLAPs) to real-world problems has been the poor achievable accuracy of these processors. Little previous research has been done on determining noise sources from a systems perspective which would include noise generated in the multiplication and addition operations, noise from spatial variations across arrays, and from crosstalk. In this dissertation, we propose a second-order statistical model for an OLAP which incorporates all these system noise sources. We now apply this knowledge to determining upper and lower bounds on the achievable accuracy. This is accomplished by first translating the standard definition of accuracy used in electronic digital processors to analog optical processors. We then employ our second-order statistical model. Having determined a general accuracy equation, we consider limiting cases such as for ideal and noisy components. From the ideal case, we find the fundamental limitations on improving analog processor accuracy. From the noisy case, we determine the practical limitations based on both device and system noise sources. These bounds allow system trade-offs to be made both in the choice of architecture and in individual components in such a way as to maximize the accuracy of the processor. Finally, by determining the fundamental limitations, we show the system engineer when the accuracy desired can be achieved from hardware or architecture improvements and when it must come from signal pre-processing and/or post-processing techniques.
Quantitative accuracy assessment of thermalhydraulic code predictions with SARBM
International Nuclear Information System (INIS)
Prosek, A.
2001-01-01
In recent years, the nuclear reactor industry has focused significant attention on nuclear reactor systems code accuracy and uncertainty issues. A few methods suitable to quantify code accuracy of thermalhydraulic code calculations were proposed and applied in the past. In this study a Stochastic Approximation Ratio Based Method (SARBM) was adapted and proposed for accuracy quantification. The objective of the study was to qualify the SARBM. The study compare the accuracy obtained by SARBM with the results obtained by widely used Fast Fourier Transform Based Method (FFTBM). The methods were applied to RELAP5/MOD3.2 code calculations of various BETHSY experiments. The obtained results showed that the SARBM was able to satisfactorily predict the accuracy of the calculated trends when visually comparing plots and comparing the results with the qualified FFTBM. The analysis also showed that the new figure-of-merit called accuracy factor (AF) is more convenient than stochastic approximation ratio for combining single variable accuracy's into total accuracy. The accuracy results obtained for the selected tests suggest that the acceptability factors for the SAR method were reasonably defined. The results also indicate that AF is a useful quantitative measure of accuracy.(author)
Forecast Accuracy Uncertainty and Momentum
Bing Han; Dong Hong; Mitch Warachka
2009-01-01
We demonstrate that stock price momentum and earnings momentum can result from uncertainty surrounding the accuracy of cash flow forecasts. Our model has multiple information sources issuing cash flow forecasts for a stock. The investor combines these forecasts into an aggregate cash flow estimate that has minimal mean-squared forecast error. This aggregate estimate weights each cash flow forecast by the estimated accuracy of its issuer, which is obtained from their past forecast errors. Mome...
Directory of Open Access Journals (Sweden)
João Rui Duarte Farias Nogueira
2012-12-01
Full Text Available Enquadramento: a ligação emocional entre pai e filho é determinante na transição para a paternidade e no desenvolvimento do bebé. Objetivos: pretendemos verificar se existe relação entre as variáveis sóciodemográficas, o envolvimento na gravidez ou o corte do cordão umbilical com a ligação emocional do pai com o bebé. Metodologia: efetuámos um estudo transversal, quantitativo de caráter descritivo analítico. Aplicámos um questionário e a escala bonding validada para a população Portuguesa (Figueiredo et al., 2005, em três momentos diferentes (durante o trabalho de parto, no 1º e no 3º dia após o parto a 222 pais, entre novembro de 2010 e janeiro de 2011. Resultados: verificámos que a idade (entre 25 e 40 anos, o acompanhamento da grávida às consultas de vigilância da gravidez, o acompanhamento da grávida nos preparativos para o nascimento do bebé, a leitura de informação sobre o bebé em desenvolvimento, o envolvimento na gravidez e o corte do cordão umbilical influenciam positivamente a ligação emocional do pai com o bebé. Conclusão: os resultados apontam para uma melhoria na ligação afetiva entre o pai e o bebé se os profissionais de saúde promoverem o envolvimento do pai na gravidez e no parto.Marco: el vínculo emocional entre padre e hijo es crucial en la transición hacia la paternidad y el desarrollo del bebé.Objetivos: pretendemos verificar si existe una relación entre las variables sociodemográficas, la participación en el embarazo o el corte del cordón umbilical y el vínculo emocional entre el padre y el bebé. Metodología: se realizó un estudio transversal, cuantitativo, de corte descriptivo-analítico. Se aplicó un cuestionario y la escala de Bonding validado para la población portuguesa (Figueiredo et al., 2005, en tres momentos diferentes (durante el parto, durante el primer y el tercer día después del parto a 222 padres, entre noviembre 2010 y enero de 2011. Resultados: se
Barausse, Enrico; Yunes, Nicolás; Chamberlain, Katie
2016-06-17
The aLIGO detection of the black-hole binary GW150914 opens a new era for probing extreme gravity. Many gravity theories predict the emission of dipole gravitational radiation by binaries. This is excluded to high accuracy in binary pulsars, but entire classes of theories predict this effect predominantly (or only) in binaries involving black holes. Joint observations of GW150914-like systems by aLIGO and eLISA will improve bounds on dipole emission from black-hole binaries by 6 orders of magnitude relative to current constraints, provided that eLISA is not dramatically descoped.
Highly accurate fluorogenic DNA sequencing with information theory-based error correction.
Chen, Zitian; Zhou, Wenxiong; Qiao, Shuo; Kang, Li; Duan, Haifeng; Xie, X Sunney; Huang, Yanyi
2017-12-01
Eliminating errors in next-generation DNA sequencing has proved challenging. Here we present error-correction code (ECC) sequencing, a method to greatly improve sequencing accuracy by combining fluorogenic sequencing-by-synthesis (SBS) with an information theory-based error-correction algorithm. ECC embeds redundancy in sequencing reads by creating three orthogonal degenerate sequences, generated by alternate dual-base reactions. This is similar to encoding and decoding strategies that have proved effective in detecting and correcting errors in information communication and storage. We show that, when combined with a fluorogenic SBS chemistry with raw accuracy of 98.1%, ECC sequencing provides single-end, error-free sequences up to 200 bp. ECC approaches should enable accurate identification of extremely rare genomic variations in various applications in biology and medicine.
Benchmark calculations of thermal reaction rates. I - Quantal scattering theory
Chatfield, David C.; Truhlar, Donald G.; Schwenke, David W.
1991-01-01
The thermal rate coefficient for the prototype reaction H + H2 yields H2 + H with zero total angular momentum is calculated by summing, averaging, and numerically integrating state-to-state reaction probabilities calculated by time-independent quantum-mechanical scattering theory. The results are very carefully converged with respect to all numerical parameters in order to provide high-precision benchmark results for confirming the accuracy of new methods and testing their efficiency.
Perspective: Fifty years of density-functional theory in chemical physics
International Nuclear Information System (INIS)
Becke, Axel D.
2014-01-01
Since its formal inception in 1964–1965, Kohn-Sham density-functional theory (KS-DFT) has become the most popular electronic structure method in computational physics and chemistry. Its popularity stems from its beautifully simple conceptual framework and computational elegance. The rise of KS-DFT in chemical physics began in earnest in the mid 1980s, when crucial developments in its exchange-correlation term gave the theory predictive power competitive with well-developed wave-function methods. Today KS-DFT finds itself under increasing pressure to deliver higher and higher accuracy and to adapt to ever more challenging problems. If we are not mindful, however, these pressures may submerge the theory in the wave-function sea. KS-DFT might be lost. I am hopeful the Kohn-Sham philosophical, theoretical, and computational framework can be preserved. This Perspective outlines the history, basic concepts, and present status of KS-DFT in chemical physics, and offers suggestions for its future development
Perspective: Fifty years of density-functional theory in chemical physics
Energy Technology Data Exchange (ETDEWEB)
Becke, Axel D., E-mail: axel.becke@dal.ca [Department of Chemistry, Dalhousie University, 6274 Coburg Rd., P.O. Box 15000, Halifax, Nova Scotia B3H 4R2 (Canada)
2014-05-14
Since its formal inception in 1964–1965, Kohn-Sham density-functional theory (KS-DFT) has become the most popular electronic structure method in computational physics and chemistry. Its popularity stems from its beautifully simple conceptual framework and computational elegance. The rise of KS-DFT in chemical physics began in earnest in the mid 1980s, when crucial developments in its exchange-correlation term gave the theory predictive power competitive with well-developed wave-function methods. Today KS-DFT finds itself under increasing pressure to deliver higher and higher accuracy and to adapt to ever more challenging problems. If we are not mindful, however, these pressures may submerge the theory in the wave-function sea. KS-DFT might be lost. I am hopeful the Kohn-Sham philosophical, theoretical, and computational framework can be preserved. This Perspective outlines the history, basic concepts, and present status of KS-DFT in chemical physics, and offers suggestions for its future development.
Directory of Open Access Journals (Sweden)
Shiqi Zhou
2011-12-01
Full Text Available Thermodynamic and structural properties of liquids are of fundamental interest in physics, chemistry, and biology, and perturbation approach has been fundamental to liquid theoretical approaches since the dawn of modern statistical mechanics and remains so to this day. Although thermodynamic perturbation theory (TPT is widely used in the chemical physics community, one of the most popular versions of the TPT, i.e. Zwanzig (Zwanzig, R. W. J. Chem. Phys. 1954, 22, 1420-1426 1st-order high temperature series expansion (HTSE TPT and its 2nd-order counterpart under a macroscopic compressibility approximation of Barker-Henderson (Barker, J. A.; Henderson, D. J. Chem. Phys. 1967, 47, 2856-2861, have some serious shortcomings: (i the nth-order term of the HTSE is involved with reference fluid distribution functions of order up to 2n, and the higher-order terms hence progressively become more complicated and numerically inaccessible; (ii the performance of the HTSE rapidly deteriorates and the calculated results become even qualitatively incorrect as the temperature of interest decreases. This account deals with the developments that we have made over the last five years or so to advance a coupling parameter series expansion (CPSE and a non hard sphere (HS perturbation strategy that has scored some of its greatest successes in overcoming the above-mentioned difficulties. In this account (i we expatiate on implementation details of our schemes: how input information indispensable to high-order truncation of the CPSE in both the HS and non HS perturbation schemes is calculated by an Ornstein-Zernike integral equation theory; how high-order thermodynamic quantities, such as critical parameters and excess constant volume heat capacity, are extracted from the resulting excess Helmholtz free energy with irregular and inevitable numerical errors; how to select reference potential in the non HS perturbation scheme. (ii We give a quantitative analysis on why
Energy Technology Data Exchange (ETDEWEB)
Zuehlsdorff, T. J., E-mail: tjz21@cam.ac.uk; Payne, M. C. [Cavendish Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Hine, N. D. M. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Haynes, P. D. [Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)
2015-11-28
We present a solution of the full time-dependent density-functional theory (TDDFT) eigenvalue equation in the linear response formalism exhibiting a linear-scaling computational complexity with system size, without relying on the simplifying Tamm-Dancoff approximation (TDA). The implementation relies on representing the occupied and unoccupied subspaces with two different sets of in situ optimised localised functions, yielding a very compact and efficient representation of the transition density matrix of the excitation with the accuracy associated with a systematic basis set. The TDDFT eigenvalue equation is solved using a preconditioned conjugate gradient algorithm that is very memory-efficient. The algorithm is validated on a small test molecule and a good agreement with results obtained from standard quantum chemistry packages is found, with the preconditioner yielding a significant improvement in convergence rates. The method developed in this work is then used to reproduce experimental results of the absorption spectrum of bacteriochlorophyll in an organic solvent, where it is demonstrated that the TDA fails to reproduce the main features of the low energy spectrum, while the full TDDFT equation yields results in good qualitative agreement with experimental data. Furthermore, the need for explicitly including parts of the solvent into the TDDFT calculations is highlighted, making the treatment of large system sizes necessary that are well within reach of the capabilities of the algorithm introduced here. Finally, the linear-scaling properties of the algorithm are demonstrated by computing the lowest excitation energy of bacteriochlorophyll in solution. The largest systems considered in this work are of the same order of magnitude as a variety of widely studied pigment-protein complexes, opening up the possibility of studying their properties without having to resort to any semiclassical approximations to parts of the protein environment.
Directory of Open Access Journals (Sweden)
L.B. Bhuiyan
2017-12-01
Full Text Available The modified Poisson-Boltzmann theory of the restricted primitive model double layer is revisited and recast in a fresh, slightly broader perspective. Derivation of relevant equations follow the techniques utilized in the earlier MPB4 and MPB5 formulations and clarifies the relationship between these. The MPB4, MPB5, and a new formulation of the theory are employed in an analysis of the structure and charge reversal phenomenon in asymmetric 2:1/1:2 valence electrolytes. Furthermore, polarization induced surface charge amplification is studied in 3:1/1:3 systems. The results are compared to the corresponding Monte Carlo simulations. The theories are seen to predict the "exact" simulation data to varying degrees of accuracy ranging from qualitative to almost quantitative. The results from a new version of the theory are found to be of comparable accuracy as the MPB5 results in many situations. However, in some cases involving low electrolyte concentrations, theoretical artifacts in the form of un-physical "shoulders" in the singlet ionic distribution functions are observed.
Solomon, Brittany C; Vazire, Simine
2014-09-01
Do romantic partners see each other realistically, or do they have overly positive perceptions of each other? Research has shown that realism and positivity co-exist in romantic partners' perceptions (Boyes & Fletcher, 2007). The current study takes a novel approach to explaining this seemingly paradoxical effect when it comes to physical attractiveness--a highly evaluative trait that is especially relevant to romantic relationships. Specifically, we argue that people are aware that others do not see their partners as positively as they do. Using both mean differences and correlational approaches, we test the hypothesis that despite their own biased and idiosyncratic perceptions, people have 2 types of partner-knowledge: insight into how their partners see themselves (i.e., identity accuracy) and insight into how others see their partners (i.e., reputation accuracy). Our results suggest that romantic partners have some awareness of each other's identity and reputation for physical attractiveness, supporting theories that couple members' perceptions are driven by motives to fulfill both esteem- and epistemic-related needs (i.e., to see their partners positively and realistically). 2014 APA, all rights reserved
Theories of Person Perception Predict Patterns of Neural Activity During Mentalizing.
Thornton, Mark A; Mitchell, Jason P
2017-08-22
Social life requires making inferences about other people. What information do perceivers spontaneously draw upon to make such inferences? Here, we test 4 major theories of person perception, and 1 synthetic theory that combines their features, to determine whether the dimensions of such theories can serve as bases for describing patterns of neural activity during mentalizing. While undergoing functional magnetic resonance imaging, participants made social judgments about well-known public figures. Patterns of brain activity were then predicted using feature encoding models that represented target people's positions on theoretical dimensions such as warmth and competence. All 5 theories of person perception proved highly accurate at reconstructing activity patterns, indicating that each could describe the informational basis of mentalizing. Cross-validation indicated that the theories robustly generalized across both targets and participants. The synthetic theory consistently attained the best performance-approximately two-thirds of noise ceiling accuracy--indicating that, in combination, the theories considered here can account for much of the neural representation of other people. Moreover, encoding models trained on the present data could reconstruct patterns of activity associated with mental state representations in independent data, suggesting the use of a common neural code to represent others' traits and states. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Accuracies Of Optical Processors For Adaptive Optics
Downie, John D.; Goodman, Joseph W.
1992-01-01
Paper presents analysis of accuracies and requirements concerning accuracies of optical linear-algebra processors (OLAP's) in adaptive-optics imaging systems. Much faster than digital electronic processor and eliminate some residual distortion. Question whether errors introduced by analog processing of OLAP overcome advantage of greater speed. Paper addresses issue by presenting estimate of accuracy required in general OLAP that yields smaller average residual aberration of wave front than digital electronic processor computing at given speed.
Analytical theory of Doppler reflectometry in slab plasma model
Energy Technology Data Exchange (ETDEWEB)
Gusakov, E.Z.; Surkov, A.V. [Ioffe Institute, Politekhnicheskaya 26, St. Petersburg (Russian Federation)
2004-07-01
Doppler reflectometry is considered in slab plasma model in the frameworks of analytical theory. The diagnostics locality is analyzed for both regimes: linear and nonlinear in turbulence amplitude. The toroidal antenna focusing of probing beam to the cut-off is proposed and discussed as a method to increase diagnostics spatial resolution. It is shown that even in the case of nonlinear regime of multiple scattering, the diagnostics can be used for an estimation (with certain accuracy) of plasma poloidal rotation profile. (authors)
Lebel, Karina; Boissy, Patrick; Hamel, Mathieu; Duval, Christian
2015-01-01
Background Interest in 3D inertial motion tracking devices (AHRS) has been growing rapidly among the biomechanical community. Although the convenience of such tracking devices seems to open a whole new world of possibilities for evaluation in clinical biomechanics, its limitations haven’t been extensively documented. The objectives of this study are: 1) to assess the change in absolute and relative accuracy of multiple units of 3 commercially available AHRS over time; and 2) to identify different sources of errors affecting AHRS accuracy and to document how they may affect the measurements over time. Methods This study used an instrumented Gimbal table on which AHRS modules were carefully attached and put through a series of velocity-controlled sustained motions including 2 minutes motion trials (2MT) and 12 minutes multiple dynamic phases motion trials (12MDP). Absolute accuracy was assessed by comparison of the AHRS orientation measurements to those of an optical gold standard. Relative accuracy was evaluated using the variation in relative orientation between modules during the trials. Findings Both absolute and relative accuracy decreased over time during 2MT. 12MDP trials showed a significant decrease in accuracy over multiple phases, but accuracy could be enhanced significantly by resetting the reference point and/or compensating for initial Inertial frame estimation reference for each phase. Interpretation The variation in AHRS accuracy observed between the different systems and with time can be attributed in part to the dynamic estimation error, but also and foremost, to the ability of AHRS units to locate the same Inertial frame. Conclusions Mean accuracies obtained under the Gimbal table sustained conditions of motion suggest that AHRS are promising tools for clinical mobility assessment under constrained conditions of use. However, improvement in magnetic compensation and alignment between AHRS modules are desirable in order for AHRS to reach their
Time-dependent density-functional theory concepts and applications
Ullrich, Carsten A
2011-01-01
Time-dependent density-functional theory (TDDFT) describes the quantum dynamics of interacting electronic many-body systems formally exactly and in a practical and efficient manner. TDDFT has become the leading method for calculating excitation energies and optical properties of large molecules, with accuracies that rival traditional wave-function based methods, but at a fraction of the computational cost.This book is the first graduate-level text on the concepts and applications of TDDFT, including many examples and exercises, and extensive coverage of the literature. The book begins with a s
Low-energy operators in effective theories
International Nuclear Information System (INIS)
Felline, C.; Piekarewicz, J.; Mehta, N.P.; Shepard, J.R.
2003-01-01
Modern effective-theory techniques are applied to the nuclear many-body problem. A novel approach is proposed for the renormalization of operators in a manner consistent with the construction of the effective potential. To test this approach, a one-dimensional, yet realistic, nucleon-nucleon potential is introduced. An effective potential is then constructed by tuning its parameters to reproduce the exact effective-range expansion and a variety of bare operators are renormalized in a fashion compatible with this construction. Predictions for the expectation values of these effective operators in the ground state reproduce the results of the exact theory with remarkable accuracy (at the 0.5% level). This represents a marked improvement over a widely practiced approach that uses effective interactions but retains bare operators. Further, it is shown that this improvement is more impressive as the operator becomes more sensitive to the short-range structure of the potential. We illustrate the main ideas of this work using the elastic form factor of the deuteron as an example
Generalized perturbation theory error control within PWR core-loading pattern optimization
International Nuclear Information System (INIS)
Imbriani, J.S.; Turinsky, P.J.; Kropaczek, D.J.
1995-01-01
The fuel management optimization code FORMOSA-P has been developed to determine the family of near-optimum loading patterns for PWR reactors. The code couples the optimization technique of simulated annealing (SA) with a generalized perturbation theory (GPT) model for evaluating core physics characteristics. To ensure the accuracy of the GPT predictions, as well as to maximize the efficient of the SA search, a GPT error control method has been developed
Assessment of a transitional boundary layer theory at low hypersonic Mach numbers
Shamroth, S. J.; Mcdonald, H.
1972-01-01
An investigation was carried out to assess the accuracy of a transitional boundary layer theory in the low hypersonic Mach number regime. The theory is based upon the simultaneous numerical solution of the boundary layer partial differential equations for the mean motion and an integral form of the turbulence kinetic energy equation which controls the magnitude and development of the Reynolds stress. Comparisions with experimental data show the theory is capable of accurately predicting heat transfer and velocity profiles through the transitional regime and correctly predicts the effects of Mach number and wall cooling on transition Reynolds number. The procedure shows promise of predicting the initiation of transition for given free stream disturbance levels. The effects on transition predictions of the pressure dilitation term and of direct absorption of acoustic energy by the boundary layer were evaluated.
MACCIA, ELIZABETH S.; AND OTHERS
AN ANNOTATED BIBLIOGRAPHY OF 20 ITEMS AND A DISCUSSION OF ITS SIGNIFICANCE WAS PRESENTED TO DESCRIBE CURRENT UTILIZATION OF SUBJECT THEORIES IN THE CONSTRUCTION OF AN EDUCATIONAL THEORY. ALSO, A THEORY MODEL WAS USED TO DEMONSTRATE CONSTRUCTION OF A SCIENTIFIC EDUCATIONAL THEORY. THE THEORY MODEL INCORPORATED SET THEORY (S), INFORMATION THEORY…
Classification Accuracy Increase Using Multisensor Data Fusion
Makarau, A.; Palubinskas, G.; Reinartz, P.
2011-09-01
The practical use of very high resolution visible and near-infrared (VNIR) data is still growing (IKONOS, Quickbird, GeoEye-1, etc.) but for classification purposes the number of bands is limited in comparison to full spectral imaging. These limitations may lead to the confusion of materials such as different roofs, pavements, roads, etc. and therefore may provide wrong interpretation and use of classification products. Employment of hyperspectral data is another solution, but their low spatial resolution (comparing to multispectral data) restrict their usage for many applications. Another improvement can be achieved by fusion approaches of multisensory data since this may increase the quality of scene classification. Integration of Synthetic Aperture Radar (SAR) and optical data is widely performed for automatic classification, interpretation, and change detection. In this paper we present an approach for very high resolution SAR and multispectral data fusion for automatic classification in urban areas. Single polarization TerraSAR-X (SpotLight mode) and multispectral data are integrated using the INFOFUSE framework, consisting of feature extraction (information fission), unsupervised clustering (data representation on a finite domain and dimensionality reduction), and data aggregation (Bayesian or neural network). This framework allows a relevant way of multisource data combination following consensus theory. The classification is not influenced by the limitations of dimensionality, and the calculation complexity primarily depends on the step of dimensionality reduction. Fusion of single polarization TerraSAR-X, WorldView-2 (VNIR or full set), and Digital Surface Model (DSM) data allow for different types of urban objects to be classified into predefined classes of interest with increased accuracy. The comparison to classification results of WorldView-2 multispectral data (8 spectral bands) is provided and the numerical evaluation of the method in comparison to
Liang, Kun; Niu, Qunjie; Wu, Xiangkui; Xu, Jiaqi; Peng, Li; Zhou, Bo
2017-09-01
A lidar system with Fabry-Pérot etalon and an intensified charge coupled device can be used to obtain the scattering spectrum of the ocean and retrieve oceanic temperature profiles. However, the spectrum would be polluted by noise and result in a measurement error. To analyze the effect of signal to noise ratio (SNR) on the accuracy of measurements for Brillouin lidar in water, the theory model and characteristics of SNR are researched. The noise spectrums with different SNR are repetitiously measured based on simulation and experiment. The results show that accuracy is related to SNR, and considering the balance of time consumption and quality, the average of five measurements is adapted for real remote sensing under the pulse laser conditions of wavelength 532 nm, pulse energy 650 mJ, repetition rate 10 Hz, pulse width 8 ns and linewidth 0.003 cm-1 (90 MHz). Measuring with the Brillouin linewidth has a better accuracy at a lower temperature (15 °C), based on the classical retrieval model we adopt. The experimental results show that the temperature error is 0.71 °C and 0.06 °C based on shift and linewidth respectively when the image SNR is at the range of 3.2 dB-3.9 dB.
Exact-to-precision generalized perturbation theory for source-driven systems
International Nuclear Information System (INIS)
Wang Congjian; Abdel-Khalik, Hany S.
2011-01-01
Highlights: ► We present a new development in higher order generalized perturbation theory. ► The method addresses the explosion in the flux phase space, input parameters, and responses. ► The method hybridizes first-order GPT and proper orthogonal decomposition snapshots method. ► A simplified 1D and realistic 2D assembly models demonstrate applicability of the method. ► The accuracy of the method is compared to exact direct perturbations and first-order GPT. - Abstract: Presented in this manuscript are new developments to perturbation theory which are intended to extend its applicability to estimate, with quantifiable accuracy, the exact variations in all responses calculated by the model with respect to all possible perturbations in the model's input parameters. The new developments place high premium on reducing the associated computational overhead in order to enable the use of perturbation theory in routine reactor design calculations. By way of examples, these developments could be employed in core simulation to accurately estimate the few-group cross-sections variations resulting from perturbations in neutronics and thermal-hydraulics core conditions. These variations are currently being described using a look-up table approach, where thousands of assembly calculations are performed to capture few-group cross-sections variations for the downstream core calculations. Other applications include the efficient evaluation of surrogates for applications that require repeated model runs such as design optimization, inverse studies, uncertainty quantification, and online core monitoring. The theoretical background of these developments applied to source-driven systems and supporting numerical experiments are presented in this manuscript. Extension to eigenvalue problems will be presented in a future article.
A note on the accuracy of KS-DFT densities
Ranasinghe, Duminda S.; Perera, Ajith; Bartlett, Rodney J.
2017-11-01
The accuracy of the density of wave function methods and Kohn-Sham (KS) density functionals is studied using moments of the density, ⟨rn ⟩ =∫ ρ (r )rnd τ =∫0∞4 π r2ρ (r ) rnd r ,where n =-1 ,-2,0,1,2 ,and 3 provides information about the short- and long-range behavior of the density. Coupled cluster (CC) singles, doubles, and perturbative triples (CCSD(T)) is considered as the reference density. Three test sets are considered: boron through neon neutral atoms, two and four electron cations, and 3d transition metals. The total density and valence only density are distinguished by dropping appropriate core orbitals. Among density functionals tested, CAMQTP00 and ωB97x show the least deviation for boron through neon neutral atoms. They also show accurate eigenvalues for the HOMO indicating that they should have a more correct long-range behavior for the density. For transition metals, some density functional approximations outperform some wave function methods, suggesting that the KS determinant could be a better starting point for some kinds of correlated calculations. By using generalized many-body perturbation theory (MBPT), the convergence of second-, third-, and fourth-order KS-MBPT for the density is addressed as it converges to the infinite-order coupled cluster result. For the transition metal test set, the deviations in the KS density functional theory methods depend on the amount of exact exchange the functional uses. Functionals with exact exchange close to 25% show smaller deviations from the CCSD(T) density.
International Nuclear Information System (INIS)
Wang, Lin; Liu, Xiongwei; Renevier, Nathalie; Stables, Matthew; Hall, George M.
2014-01-01
Due to the increasing size and flexibility of large wind turbine blades, accurate and reliable aeroelastic modelling is playing an important role for the design of large wind turbines. Most existing aeroelastic models are linear models based on assumption of small blade deflections. This assumption is not valid anymore for very flexible blade design because such blades often experience large deflections. In this paper, a novel nonlinear aeroelastic model for large wind turbine blades has been developed by combining BEM (blade element momentum) theory and mixed-form formulation of GEBT (geometrically exact beam theory). The nonlinear aeroelastic model takes account of large blade deflections and thus greatly improves the accuracy of aeroelastic analysis of wind turbine blades. The nonlinear aeroelastic model is implemented in COMSOL Multiphysics and validated with a series of benchmark calculation tests. The results show that good agreement is achieved when compared with experimental data, and its capability of handling large deflections is demonstrated. Finally the nonlinear aeroelastic model is applied to aeroelastic modelling of the parked WindPACT 1.5 MW baseline wind turbine, and reduced flapwise deflection from the nonlinear aeroelastic model is observed compared to the linear aeroelastic code FAST (Fatigue, Aerodynamics, Structures, and Turbulence). - Highlights: • A novel nonlinear aeroelastic model for wind turbine blades is developed. • The model takes account of large blade deflections and geometric nonlinearities. • The model is reliable and efficient for aeroelastic modelling of wind turbine blades. • The accuracy of the model is verified by a series of benchmark calculation tests. • The model provides more realistic aeroelastic modelling than FAST (Fatigue, Aerodynamics, Structures, and Turbulence)
Directory of Open Access Journals (Sweden)
Pedro Miguel Silva
2011-09-01
Full Text Available O nível competitivo alcançado pelo futebol profissional tem exigido níveis de desempenho cada vez mais elevados. Uma das formas que tem sido utilizada para monitorá-la é a análise do jogo (AJ. O presente trabalho pretendeu caracterizar o processo de AJ na 1ª liga portuguesa profissional de futebol. Os objetivos do estudo foram conhecer: 1 a importância da AJ; 2 a frequência da sua realização; 3 os profissionais envolvidos; 4 os instrumentos e métodos utilizados; e 5 a importância atribuída pelos treinadores a diferentes eixos de análise. A amostra foi constituída por 16 treinadores da 1ª liga portuguesa de futebol profissional 2005/2006 (89% do universo em estudo. A cada um deles foi aplicado um questionário previamente validado por oito especialistas. Os resultados obtidos revelaram que a AJ adquire a sua pertinência ao nível da planificação tático-estratégica. É comumente utilizado um instrumento com categorias predefinidas e os eixos de análise eleitos estão relacionados com a dimensão tático-estratégica do jogo. O treinador principal é o protagonista na análise do jogo da sua equipe, delegando a função de análise dos adversários num profissional da equipe técnica. Os sistemas de análise utilizados não são sofisticados e apenas uma minoria admite recorrer à informática. Os eixos de análise menos valorizados estão relacionados com a análise energético-funcional dos jogadores. Sintetizando, na referida liga o processo de AJ é sistematizado e foca preferencialmente a vertente táctico-estratégica dos jogos analisados. No entanto, apesar de serem utilizados instrumentos com categorias predefinidas, os sistemas de análise utilizados são pouco sofisticado.Nowadays, the competitive level achieved by professional football has required performance levels to increase highly. Match analysis is one of the tools that has been used to control performance. The aim of this work was to characterise match
Surgical accuracy of three-dimensional virtual planning
DEFF Research Database (Denmark)
Stokbro, Kasper; Aagaard, Esben; Torkov, Peter
2016-01-01
This retrospective study evaluated the precision and positional accuracy of different orthognathic procedures following virtual surgical planning in 30 patients. To date, no studies of three-dimensional virtual surgical planning have evaluated the influence of segmentation on positional accuracy...... and transverse expansion. Furthermore, only a few have evaluated the precision and accuracy of genioplasty in placement of the chin segment. The virtual surgical plan was compared with the postsurgical outcome by using three linear and three rotational measurements. The influence of maxillary segmentation...
Vu, Tuong-Van; Finkenauer, Catrin; Huizinga, Mariette; Novin, Sheida; Krabbendam, Lydia
2017-01-01
This study investigated whether individualism and collectivism (IC) at country, individual, and situational level influence how quickly and accurately people can infer mental states (i.e. theory of mind, or ToM), indexed by accuracy and reaction time in a ToM task. We hypothesized that collectivism (having an interdependent self and valuing group concerns), compared to individualism (having an independent self and valuing personal concerns), is associated with greater accuracy and speed in re...
FIELD ACCURACY TEST OF RPAS PHOTOGRAMMETRY
Directory of Open Access Journals (Sweden)
P. Barry
2013-08-01
Full Text Available Baseline Surveys Ltd is a company which specialises in the supply of accurate geospatial data, such as cadastral, topographic and engineering survey data to commercial and government bodies. Baseline Surveys Ltd invested in aerial drone photogrammetric technology and had a requirement to establish the spatial accuracy of the geographic data derived from our unmanned aerial vehicle (UAV photogrammetry before marketing our new aerial mapping service. Having supplied the construction industry with survey data for over 20 years, we felt that is was crucial for our clients to clearly understand the accuracy of our photogrammetry so they can safely make informed spatial decisions, within the known accuracy limitations of our data. This information would also inform us on how and where UAV photogrammetry can be utilised. What we wanted to find out was the actual accuracy that can be reliably achieved using a UAV to collect data under field conditions throughout a 2 Ha site. We flew a UAV over the test area in a "lawnmower track" pattern with an 80% front and 80% side overlap; we placed 45 ground markers as check points and surveyed them in using network Real Time Kinematic Global Positioning System (RTK GPS. We specifically designed the ground markers to meet our accuracy needs. We established 10 separate ground markers as control points and inputted these into our photo modelling software, Agisoft PhotoScan. The remaining GPS coordinated check point data were added later in ArcMap to the completed orthomosaic and digital elevation model so we could accurately compare the UAV photogrammetry XYZ data with the RTK GPS XYZ data at highly reliable common points. The accuracy we achieved throughout the 45 check points was 95% reliably within 41 mm horizontally and 68 mm vertically and with an 11.7 mm ground sample distance taken from a flight altitude above ground level of 90 m.The area covered by one image was 70.2 m × 46.4 m, which equals 0.325 Ha. This
Extension of Kirkwood-Buff theory to the canonical ensemble
Rogers, David M.
2018-02-01
Kirkwood-Buff (KB) integrals are notoriously difficult to converge from a canonical simulation because they require estimating the grand-canonical radial distribution. The same essential difficulty is encountered when attempting to estimate the direct correlation function of Ornstein-Zernike theory by inverting the pair correlation functions. We present a new theory that applies to the entire, finite, simulation volume, so that no cutoff issues arise at all. The theory gives the direct correlation function for closed systems, while smoothness of the direct correlation function in reciprocal space allows calculating canonical KB integrals via a well-posed extrapolation to the origin. The present analysis method represents an improvement over previous work because it makes use of the entire simulation volume and its convergence can be accelerated using known properties of the direct correlation function. Using known interaction energy functions can make this extrapolation near perfect accuracy in the low-density case. Because finite size effects are stronger in the canonical than in the grand-canonical ensemble, we state ensemble correction formulas for the chemical potential and the KB coefficients. The new theory is illustrated with both analytical and simulation results on the 1D Ising model and a supercritical Lennard-Jones fluid. For the latter, the finite-size corrections are shown to be small.
International Nuclear Information System (INIS)
Garrett, B.C.; Truhlar, D.G.
1979-01-01
Canonical variational transition state theory, microcanonical variational transition state theory, and Miller's unified statistical theory were used in an attempt to correct two major deficiencies of the conventional transition state theory. These are: (1) the necessity of extra assumptions to include quantum mechanical tunneling effects and (2) the fundamental assumption that trajectories crossing a dividing surface in phase space proceed directly to products. The accuracy of these approximate methods were tested by performing calculations for several collinear reactions of hydrogen, deuterium, chlorine, or iodine, with five isotopes of hydrogen molecules and comparison of these results with those from accurate quantitative calculations of the reaction probabilities as functions of energy and of the thermal rate constants as functions of temperature. 49 references, 28 figures, 17 tables
A Novel Robust H∞ Filter Based on Krein Space Theory in the SINS/CNS Attitude Reference System
Directory of Open Access Journals (Sweden)
Fei Yu
2016-03-01
Full Text Available Owing to their numerous merits, such as compact, autonomous and independence, the strapdown inertial navigation system (SINS and celestial navigation system (CNS can be used in marine applications. What is more, due to the complementary navigation information obtained from two different kinds of sensors, the accuracy of the SINS/CNS integrated navigation system can be enhanced availably. Thus, the SINS/CNS system is widely used in the marine navigation field. However, the CNS is easily interfered with by the surroundings, which will lead to the output being discontinuous. Thus, the uncertainty problem caused by the lost measurement will reduce the system accuracy. In this paper, a robust H∞ filter based on the Krein space theory is proposed. The Krein space theory is introduced firstly, and then, the linear state and observation models of the SINS/CNS integrated navigation system are established reasonably. By taking the uncertainty problem into account, in this paper, a new robust H∞ filter is proposed to improve the robustness of the integrated system. At last, this new robust filter based on the Krein space theory is estimated by numerical simulations and actual experiments. Additionally, the simulation and experiment results and analysis show that the attitude errors can be reduced by utilizing the proposed robust filter effectively when the measurements are missing discontinuous. Compared to the traditional Kalman filter (KF method, the accuracy of the SINS/CNS integrated system is improved, verifying the robustness and the availability of the proposed robust H∞ filter.
On the accuracy of analyses for in-plane bending of smooth pipe bends with end constraints
International Nuclear Information System (INIS)
Thomson, G.; Spence, J.
1985-01-01
The accuracy of theoretical analyses for in-plane bending of smooth pipebends with end constraints is discussed and investigated with a view to explaining and reducing the differences between the major works. An earlier theory of the authors is improved to give more accurate answers for bends with rigid flanges. Flanged bends are then examined in some detail, quantifying for the first time the important influence of the flange rigidity on the bend flexibility and stresses. A summary of some finite element analyses is presented from which it is clear that further work is desirable. (orig.)
A global numerical solution of the radial Schroedinger equation by second-order perturbation theory
International Nuclear Information System (INIS)
Adam, G.
1979-01-01
A global numerical method, which uses second-order perturbation theory, is described for the solution of the radial Schroedinger equation. The perturbative numerical (PN) solution is derived in two stages: first, the original potential is approximated by a piecewise continuous parabolic function, and second, the resulting Schroedinger equation is solved on each integration step by second-order perturbation theory, starting with a step function reference approximation for the parabolic potential. We get a manageable PN algorithm, which shows an order of accuracy equal to six in the solution of the original Schroedinger equation, and is very stable against round off errors. (author)
Spacecraft TT&C and information transmission theory and technologies
Liu, Jiaxing
2015-01-01
Spacecraft TT&C and Information Transmission Theory and Technologies introduces the basic theory of spacecraft TT&C (telemetry, track and command) and information transmission. Combining TT&C and information transmission, the book presents several technologies for continuous wave radar including measurements for range, range rate and angle, analog and digital information transmissions, telecommand, telemetry, remote sensing and spread spectrum TT&C. For special problems occurred in the channels for TT&C and information transmission, the book represents radio propagation features and its impact on orbit measurement accuracy, and the effects caused by rain attenuation, atmospheric attenuation and multi-path effect, and polarization composition technology. This book can benefit researchers and engineers in the field of spacecraft TT&C and communication systems. Liu Jiaxing is a professor at The 10th Institute of China Electronics Technology Group Corporation.
Convergence problems associated with the iteration of adjoint equations in nuclear reactor theory
International Nuclear Information System (INIS)
Ngcobo, E.
2003-01-01
Convergence problems associated with the iteration of adjoint equations based on two-group neutron diffusion theory approximations in slab geometry are considered. For this purpose first-order variational techniques are adopted to minimise numerical errors involved. The importance of deriving the adjoint source from a breeding ratio is illustrated. The results obtained are consistent with the expected improvement in accuracy
How the Laser Helped to Improve the Test of Special Theory of Relativity?
Singh, Satya Pal
2013-01-01
In this paper of I have reviewed the test done for validating the special theory of relativity using masers and lasers in last one century. Michelson-Morley did the first experimental verification for the isotropy of space for the propagation of light in 1887. It has an accuracy of 1/100th of a fringe shift. The predicted fringe shift on the basis…
String theory or field theory?
International Nuclear Information System (INIS)
Marshakov, Andrei V
2002-01-01
The status of string theory is reviewed, and major recent developments - especially those in going beyond perturbation theory in the string theory and quantum field theory frameworks - are analyzed. This analysis helps better understand the role and place of string theory in the modern picture of the physical world. Even though quantum field theory describes a wide range of experimental phenomena, it is emphasized that there are some insurmountable problems inherent in it - notably the impossibility to formulate the quantum theory of gravity on its basis - which prevent it from being a fundamental physical theory of the world of microscopic distances. It is this task, the creation of such a theory, which string theory, currently far from completion, is expected to solve. In spite of its somewhat vague current form, string theory has already led to a number of serious results and greatly contributed to progress in the understanding of quantum field theory. It is these developments which are our concern in this review. (reviews of topical problems)
Accuracy of Binary Black Hole Waveform Models for Advanced LIGO
Kumar, Prayush; Fong, Heather; Barkett, Kevin; Bhagwat, Swetha; Afshari, Nousha; Chu, Tony; Brown, Duncan; Lovelace, Geoffrey; Pfeiffer, Harald; Scheel, Mark; Szilagyi, Bela; Simulating Extreme Spacetimes (SXS) Team
2016-03-01
Coalescing binaries of compact objects, such as black holes and neutron stars, are the primary targets for gravitational-wave (GW) detection with Advanced LIGO. Accurate modeling of the emitted GWs is required to extract information about the binary source. The most accurate solution to the general relativistic two-body problem is available in numerical relativity (NR), which is however limited in application due to computational cost. Current searches use semi-analytic models that are based in post-Newtonian (PN) theory and calibrated to NR. In this talk, I will present comparisons between contemporary models and high-accuracy numerical simulations performed using the Spectral Einstein Code (SpEC), focusing at the questions: (i) How well do models capture binary's late-inspiral where they lack a-priori accurate information from PN or NR, and (ii) How accurately do they model binaries with parameters outside their range of calibration. These results guide the choice of templates for future GW searches, and motivate future modeling efforts.
Discrete Curvature Theories and Applications
Sun, Xiang
2016-08-25
Discrete Di erential Geometry (DDG) concerns discrete counterparts of notions and methods in di erential geometry. This thesis deals with a core subject in DDG, discrete curvature theories on various types of polyhedral surfaces that are practically important for free-form architecture, sunlight-redirecting shading systems, and face recognition. Modeled as polyhedral surfaces, the shapes of free-form structures may have to satisfy di erent geometric or physical constraints. We study a combination of geometry and physics { the discrete surfaces that can stand on their own, as well as having proper shapes for the manufacture. These proper shapes, known as circular and conical meshes, are closely related to discrete principal curvatures. We study curvature theories that make such surfaces possible. Shading systems of freeform building skins are new types of energy-saving structures that can re-direct the sunlight. From these systems, discrete line congruences across polyhedral surfaces can be abstracted. We develop a new curvature theory for polyhedral surfaces equipped with normal congruences { a particular type of congruences de ned by linear interpolation of vertex normals. The main results are a discussion of various de nitions of normality, a detailed study of the geometry of such congruences, and a concept of curvatures and shape operators associated with the faces of a triangle mesh. These curvatures are compatible with both normal congruences and the Steiner formula. In addition to architecture, we consider the role of discrete curvatures in face recognition. We use geometric measure theory to introduce the notion of asymptotic cones associated with a singular subspace of a Riemannian manifold, which is an extension of the classical notion of asymptotic directions. We get a simple expression of these cones for polyhedral surfaces, as well as convergence and approximation theorems. We use the asymptotic cones as facial descriptors and demonstrate the
A high-accuracy extraction of the isoscalar πN scattering length from pionic deuterium data
International Nuclear Information System (INIS)
Phillips, Daniel R.; Baru, Vadim; Hanhart, Christoph; Nogga, Andreas; Hoferichter, Martin; Kubis, Bastian
2010-01-01
We present a high-accuracy calculation of the π(bar sign)d scattering length using chiral perturbation theory up to order (M π /m p ) 7/2 . For the first time isospin-violating corrections are included consistently. The resulting value of a π -bar d has a theoretical uncertainty of a few percent. We use it, together with data on pionic deuterium and pionic hydrogen atoms, to extract the isoscalar and isovector pion-nucleon scattering lengths from a combined analysis, and obtain a + (7.9±3.2)·10 -3 M π -1 and a-bar (86.3±1.0)·10 -3 M π -1 .
Accuracy Assessment and Analysis for GPT2
Directory of Open Access Journals (Sweden)
YAO Yibin
2015-07-01
Full Text Available GPT(global pressure and temperature is a global empirical model usually used to provide temperature and pressure for the determination of tropospheric delay, there are some weakness to GPT, these have been improved with a new empirical model named GPT2, which not only improves the accuracy of temperature and pressure, but also provides specific humidity, water vapor pressure, mapping function coefficients and other tropospheric parameters, and no accuracy analysis of GPT2 has been made until now. In this paper high-precision meteorological data from ECWMF and NOAA were used to test and analyze the accuracy of temperature, pressure and water vapor pressure expressed by GPT2, testing results show that the mean Bias of temperature is -0.59℃, average RMS is 3.82℃; absolute value of average Bias of pressure and water vapor pressure are less than 1 mb, GPT2 pressure has average RMS of 7 mb, and water vapor pressure no more than 3 mb, accuracy is different in different latitudes, all of them have obvious seasonality. In conclusion, GPT2 model has high accuracy and stability on global scale.
Cosmic microwave background theory
Bond, J. Richard
1998-01-01
A long-standing goal of theorists has been to constrain cosmological parameters that define the structure formation theory from cosmic microwave background (CMB) anisotropy experiments and large-scale structure (LSS) observations. The status and future promise of this enterprise is described. Current band-powers in ℓ-space are consistent with a ΔT flat in frequency and broadly follow inflation-based expectations. That the levels are ∼(10−5)2 provides strong support for the gravitational instability theory, while the Far Infrared Absolute Spectrophotometer (FIRAS) constraints on energy injection rule out cosmic explosions as a dominant source of LSS. Band-powers at ℓ ≳ 100 suggest that the universe could not have re-ionized too early. To get the LSS of Cosmic Background Explorer (COBE)-normalized fluctuations right provides encouraging support that the initial fluctuation spectrum was not far off the scale invariant form that inflation models prefer: e.g., for tilted Λ cold dark matter sequences of fixed 13-Gyr age (with the Hubble constant H0 marginalized), ns = 1.17 ± 0.3 for Differential Microwave Radiometer (DMR) only; 1.15 ± 0.08 for DMR plus the SK95 experiment; 1.00 ± 0.04 for DMR plus all smaller angle experiments; 1.00 ± 0.05 when LSS constraints are included as well. The CMB alone currently gives weak constraints on Λ and moderate constraints on Ωtot, but theoretical forecasts of future long duration balloon and satellite experiments are shown which predict percent-level accuracy among a large fraction of the 10+ parameters characterizing the cosmic structure formation theory, at least if it is an inflation variant. PMID:9419321
Decision Accuracy in Computer-Mediated versus Face-to-Face Decision-Making Teams.
Hedlund; Ilgen; Hollenbeck
1998-10-01
Changes in the way organizations are structured and advances in communication technologies are two factors that have altered the conditions under which group decisions are made. Decisions are increasingly made by teams that have a hierarchical structure and whose members have different areas of expertise. In addition, many decisions are no longer made via strictly face-to-face interaction. The present study examines the effects of two modes of communication (face-to-face or computer-mediated) on the accuracy of teams' decisions. The teams are characterized by a hierarchical structure and their members differ in expertise consistent with the framework outlined in the Multilevel Theory of team decision making presented by Hollenbeck, Ilgen, Sego, Hedlund, Major, and Phillips (1995). Sixty-four four-person teams worked for 3 h on a computer simulation interacting either face-to-face (FtF) or over a computer network. The communication mode had mixed effects on team processes in that members of FtF teams were better informed and made recommendations that were more predictive of the correct team decision, but leaders of CM teams were better able to differentiate staff members on the quality of their decisions. Controlling for the negative impact of FtF communication on staff member differentiation increased the beneficial effect of the FtF mode on overall decision making accuracy. Copyright 1998 Academic Press.
Accuracy in Optical Information Processing
Timucin, Dogan Aslan
Low computational accuracy is an important obstacle for optical processors which blocks their way to becoming a practical reality and a serious challenger for classical computing paradigms. This research presents a comprehensive solution approach to the problem of accuracy enhancement in discrete analog optical information processing systems. Statistical analysis of a generic three-plane optical processor is carried out first, taking into account the effects of diffraction, interchannel crosstalk, and background radiation. Noise sources included in the analysis are photon, excitation, and emission fluctuations in the source array, transmission and polarization fluctuations in the modulator, and photoelectron, gain, dark, shot, and thermal noise in the detector array. Means and mutual coherence and probability density functions are derived for both optical and electrical output signals. Next, statistical models for a number of popular optoelectronic devices are studied. Specific devices considered here are light-emitting and laser diode sources, an ideal noiseless modulator and a Gaussian random-amplitude-transmittance modulator, p-i-n and avalanche photodiode detectors followed by electronic postprocessing, and ideal free-space geometrical -optics propagation and single-lens imaging systems. Output signal statistics are determined for various interesting device combinations by inserting these models into the general formalism. Finally, based on these special-case output statistics, results on accuracy limitations and enhancement in optical processors are presented. Here, starting with the formulation of the accuracy enhancement problem as (1) an optimal detection problem and (2) as a parameter estimation problem, the potential accuracy improvements achievable via the classical multiple-hypothesis -testing and maximum likelihood and Bayesian parameter estimation methods are demonstrated. Merits of using proper normalizing transforms which can potentially stabilize
Becker, Katrin; Becker, Melanie; Schwarz, John H.
String theory is one of the most exciting and challenging areas of modern theoretical physics. This book guides the reader from the basics of string theory to recent developments. It introduces the basics of perturbative string theory, world-sheet supersymmetry, space-time supersymmetry, conformal field theory and the heterotic string, before describing modern developments, including D-branes, string dualities and M-theory. It then covers string geometry and flux compactifications, applications to cosmology and particle physics, black holes in string theory and M-theory, and the microscopic origin of black-hole entropy. It concludes with Matrix theory, the AdS/CFT duality and its generalizations. This book is ideal for graduate students and researchers in modern string theory, and will make an excellent textbook for a one-year course on string theory. It contains over 120 exercises with solutions, and over 200 homework problems with solutions available on a password protected website for lecturers at www.cambridge.org/9780521860697. Comprehensive coverage of topics from basics of string theory to recent developments Ideal textbook for a one-year course in string theory Includes over 100 exercises with solutions Contains over 200 homework problems with solutions available to lecturers on-line
String theory or field theory?
International Nuclear Information System (INIS)
Marshakov, A.V.
2002-01-01
The status of string theory is reviewed, and major recent developments - especially those in going beyond perturbation theory in the string theory and quantum field theory frameworks - are analyzed. This analysis helps better understand the role and place of experimental phenomena, it is emphasized that there are some insurmountable problems inherent in it - notably the impossibility to formulate the quantum theory of gravity on its basis - which prevent it from being a fundamental physical theory of the world of microscopic distances. It is this task, the creation of such a theory, which string theory, currently far from completion, is expected to solve. In spite of its somewhat vague current form, string theory has already led to a number of serious results and greatly contributed to progress in the understanding of quantum field theory. It is these developments, which are our concern in this review [ru
High Accuracy Transistor Compact Model Calibrations
Energy Technology Data Exchange (ETDEWEB)
Hembree, Charles E. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Mar, Alan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Robertson, Perry J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
2015-09-01
Typically, transistors are modeled by the application of calibrated nominal and range models. These models consists of differing parameter values that describe the location and the upper and lower limits of a distribution of some transistor characteristic such as current capacity. Correspond- ingly, when using this approach, high degrees of accuracy of the transistor models are not expected since the set of models is a surrogate for a statistical description of the devices. The use of these types of models describes expected performances considering the extremes of process or transistor deviations. In contrast, circuits that have very stringent accuracy requirements require modeling techniques with higher accuracy. Since these accurate models have low error in transistor descriptions, these models can be used to describe part to part variations as well as an accurate description of a single circuit instance. Thus, models that meet these stipulations also enable the calculation of quantifi- cation of margins with respect to a functional threshold and uncertainties in these margins. Given this need, new model high accuracy calibration techniques for bipolar junction transis- tors have been developed and are described in this report.
A prediction method based on grey system theory in equipment condition based maintenance
International Nuclear Information System (INIS)
Yan, Shengyuan; Yan, Shengyuan; Zhang, Hongguo; Zhang, Zhijian; Peng, Minjun; Yang, Ming
2007-01-01
Grey prediction is a modeling method based on historical or present, known or indefinite information, which can be used for forecasting the development of the eigenvalues of the targeted equipment system and setting up the model by using less information. In this paper, the postulate of grey system theory, which includes the grey generating, the sorts of grey generating and the grey forecasting model, is introduced first. The concrete application process, which includes the grey prediction modeling, grey prediction, error calculation, equal dimension and new information approach, is introduced secondly. Application of a so-called 'Equal Dimension and New Information' (EDNI) technology in grey system theory is adopted in an application case, aiming at improving the accuracy of prediction without increasing the amount of calculation by replacing old data with new ones. The proposed method can provide a new way for solving the problem of eigenvalue data exploding in equal distance effectively, short time interval and real time prediction. The proposed method, which was based on historical or present, known or indefinite information, was verified by the vibration prediction of induced draft fan of a boiler of the Yantai Power Station in China, and the results show that the proposed method based on grey system theory is simple and provides a high accuracy in prediction. So, it is very useful and significant to the controlling and controllable management in safety production. (authors)
Accuracy and Reliability of Peer Assessment of Athletic Training Psychomotor Laboratory Skills
Marty, Melissa C.; Henning, Jolene M.; Willse, John T.
2010-01-01
Abstract Context: Peer assessment is defined as students judging the level or quality of a fellow student's understanding. No researchers have yet demonstrated the accuracy or reliability of peer assessment in athletic training education. Objective: To determine the accuracy and reliability of peer assessment of athletic training students' psychomotor skills. Design: Cross-sectional study. Setting: Entry-level master's athletic training education program. Patients or Other Participants: First-year (n = 5) and second-year (n = 8) students. Main Outcome Measure(s): Participants evaluated 10 videos of a peer performing 3 psychomotor skills (middle deltoid manual muscle test, Faber test, and Slocum drawer test) on 2 separate occasions using a valid assessment tool. Accuracy of each peer-assessment score was examined through percentage correct scores. We used a generalizability study to determine how reliable athletic training students were in assessing a peer performing the aforementioned skills. Decision studies using generalizability theory demonstrated how the peer-assessment scores were affected by the number of participants and number of occasions. Results: Participants had a high percentage of correct scores: 96.84% for the middle deltoid manual muscle test, 94.83% for the Faber test, and 97.13% for the Slocum drawer test. They were not able to reliably assess a peer performing any of the psychomotor skills on only 1 occasion. However, the ϕ increased (exceeding the 0.70 minimal standard) when 2 participants assessed the skill on 3 occasions (ϕ = 0.79) for the Faber test, with 1 participant on 2 occasions (ϕ = 0.76) for the Slocum drawer test, and with 3 participants on 2 occasions for the middle deltoid manual muscle test (ϕ = 0.72). Conclusions: Although students did not detect all errors, they assessed their peers with an average of 96% accuracy. Having only 1 student assess a peer performing certain psychomotor skills was
Certain theories of multiple scattering in random media of discrete scatterers
International Nuclear Information System (INIS)
Olsen, R.L.; Kharadly, M.M.Z.; Corr, D.G.
1976-01-01
New information is presented on the accuracy of the heuristic approximations in two important theories of multiple scattering in random media of discrete scatterers: Twersky's ''free-space'' and ''two-space scatterer'' formalisms. Two complementary approaches, based primarily on a one-dimensional model and the one-dimensional forms of the theories, are used. For scatterer distributions of low average density, the ''heuristic'' asymptotic forms for the coherent field and the incoherent intensity are compared with asymptotic forms derived from a systematic analysis of the multiple scattering processes. For distributions of higher density, both in the average number of scatterers per wavelength and in the degree of packing of finite-size scatterers, the analysis is carried out ''experimentally'' by means of a Monte Carlo computer simulation. Approximate series expressions based on the systematic approach are numerically evaluated along with the heuristic expressions. The comparison (for both forward- and back-scattered field moments) is made for the worst-case conditions of strong multiple scattering for which the theories have not previously been evaluated. Several significant conclusions are drawn which have certain practical implications: in application of the theories to describe some of the scattering phenomena which occur in the troposphere, and in the further evaluation of the theories using experiments on physical models
Soldagem por ponto no estado sólido de ligas leves Solid state spot welding of lightweight alloys
Directory of Open Access Journals (Sweden)
Leonardo Contri Campanelli
2011-09-01
Full Text Available A recente preocupação quanto às mudanças climáticas vem impulsionando pesquisas em eficiência energética dos meios de transportes no sentido de reduzir a emissão de gases. Uma das principais soluções consiste na redução do peso estrutural através da aplicação de novos materiais, como as ligas leves de alumínio e magnésio. Entretanto, novos usos ficam muitas vezes limitados pela dificuldade de união desses materiais. A técnica de soldagem por fricção e mistura (FSW é um processo de união no estado sólido que surge como uma alternativa viável para substituir ou complementar as tecnologias de união consagradas. Como uma junta contínua não é sempre a requisitada, duas tecnologias de união por ponto derivadas do FSW estão em desenvolvimento: soldagem por fricção e mistura por ponto (FSSW e soldagem por fricção por ponto (FSpW. Além de fornecerem juntas de elevada resistência e praticamente isentas de defeitos, estas técnicas apresentam alta eficiência energética, curto ciclo de soldagem, facilidade de automação e compatibilidade com o meio-ambiente, fazendo frente às técnicas convencionais de união por ponto, como a soldagem por resistência por ponto (RSW e a rebitagem.The recent concern about climate change has stimulated research into transport energy efficiency in order to reduce the emission of gases. One of the main solutions is to reduce the structural weight through the application of new materials, such as aluminum and magnesium lightweight alloys. However, new applications are often limited by the difficulty of joining these materials. Friction Stir Welding (FSW is a solid state joining technique that emerges as a viable alternative to replace or complement the established joining technologies. As a continuous weld is not always requested, two spot welding technologies derived from FSW are under development: Friction Stir Spot Welding (FSSW and Friction Spot Welding (FSpW. Besides providing
Directory of Open Access Journals (Sweden)
Coomarasamy Aravinthan
2004-05-01
Full Text Available Abstract Background To empirically evaluate bias in estimation of accuracy associated with delay in verification of diagnosis among studies evaluating tests for predicting endometrial hyperplasia. Methods Systematic reviews of all published research on accuracy of miniature endometrial biopsy and endometr ial ultrasonography for diagnosing endometrial hyperplasia identified 27 test accuracy studies (2,982 subjects. Of these, 16 had immediate histological verification of diagnosis while 11 had verification delayed > 24 hrs after testing. The effect of delay in verification of diagnosis on estimates of accuracy was evaluated using meta-regression with diagnostic odds ratio (dOR as the accuracy measure. This analysis was adjusted for study quality and type of test (miniature endometrial biopsy or endometrial ultrasound. Results Compared to studies with immediate verification of diagnosis (dOR 67.2, 95% CI 21.7–208.8, those with delayed verification (dOR 16.2, 95% CI 8.6–30.5 underestimated the diagnostic accuracy by 74% (95% CI 7%–99%; P value = 0.048. Conclusion Among studies of miniature endometrial biopsy and endometrial ultrasound, diagnostic accuracy is considerably underestimated if there is a delay in histological verification of diagnosis.
Inference of Altimeter Accuracy on Along-track Gravity Anomaly Recovery
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LI Yang
2015-04-01
Full Text Available A correlation model between along-track gravity anomaly accuracy, spatial resolution and altimeter accuracy is proposed. This new model is based on along-track gravity anomaly recovery and resolution estimation. Firstly, an error propagation formula of along-track gravity anomaly is derived from the principle of satellite altimetry. Then the mathematics between the SNR (signal to noise ratio and cross spectral coherence is deduced. The analytical correlation between altimeter accuracy and spatial resolution is finally obtained from the results above. Numerical simulation results show that along-track gravity anomaly accuracy is proportional to altimeter accuracy, while spatial resolution has a power relation with altimeter accuracy. e.g., with altimeter accuracy improving m times, gravity anomaly accuracy improves m times while spatial resolution improves m0.4644 times. This model is verified by real-world data.
Robust global identifiability theory using potentials--Application to compartmental models.
Wongvanich, N; Hann, C E; Sirisena, H R
2015-04-01
This paper presents a global practical identifiability theory for analyzing and identifying linear and nonlinear compartmental models. The compartmental system is prolonged onto the potential jet space to formulate a set of input-output equations that are integrals in terms of the measured data, which allows for robust identification of parameters without requiring any simulation of the model differential equations. Two classes of linear and non-linear compartmental models are considered. The theory is first applied to analyze the linear nitrous oxide (N2O) uptake model. The fitting accuracy of the identified models from differential jet space and potential jet space identifiability theories is compared with a realistic noise level of 3% which is derived from sensor noise data in the literature. The potential jet space approach gave a match that was well within the coefficient of variation. The differential jet space formulation was unstable and not suitable for parameter identification. The proposed theory is then applied to a nonlinear immunological model for mastitis in cows. In addition, the model formulation is extended to include an iterative method which allows initial conditions to be accurately identified. With up to 10% noise, the potential jet space theory predicts the normalized population concentration infected with pathogens, to within 9% of the true curve. Copyright © 2015 Elsevier Inc. All rights reserved.
Daul, Claude
2014-09-01
Despite the important growth of ab initio and computational techniques, ligand field theory in molecular science or crystal field theory in condensed matter offers the most intuitive way to calculate multiplet energy levels arising from systems with open shells d and/or f electrons. Over the past decade we have developed a ligand field treatment of inorganic molecular modelling taking advantage of the dominant localization of the frontier orbitals within the metal-sphere. This feature, which is observed in any inorganic coordination compound, especially if treated by Density Functional Theory calculation, allows the determination of the electronic structure and properties with a surprising good accuracy. In ligand field theory, the theoretical concepts consider only a single atom center; and treat its interaction with the chemical environment essentially as a perturbation. Therefore success in the simple ligand field theory is no longer questionable, while the more accurate molecular orbital theory does in general over-estimate the metal-ligand covalence, thus yields wave functions that are too delocalized. Although LF theory has always been popular as a semi-empirical method when dealing with molecules of high symmetry e.g. cubic symmetry where the number of parameters needed is reasonably small (3 or 5), this is no more the case for molecules without symmetry and involving both an open d- and f-shell (# parameters ∼90). However, the combination of LF theory and Density Functional (DF) theory that we introduced twenty years ago can easily deal with complex molecules of any symmetry with two and more open shells. The accuracy of these predictions from 1(st) principles achieves quite a high accuracy (<5%) in terms of states energies. Hence, this approach is well suited to predict the magnetic and photo-physical properties arbitrary molecules and materials prior to their synthesis, which is the ultimate goal of each computational chemist. We will illustrate the
Theory, analysis and design of RF interferometric sensors
Nguyen, Cam
2012-01-01
Theory, Analysis and Design of RF Interferometric Sensors presents the theory, analysis and design of RF interferometric sensors. RF interferometric sensors are attractive for various sensing applications that require every fine resolution and accuracy as well as fast speed. The book also presents two millimeter-wave interferometric sensors realized using RF integrated circuits. The developed millimeter-wave homodyne sensor shows sub-millimeter resolution in the order of 0.05 mm without correction for the non-linear phase response of the sensor's quadrature mixer. The designed millimeter-wave double-channel homodyne sensor provides a resolution of only 0.01 mm, or 1/840th of the operating wavelength, and can inherently suppress the non-linearity of the sensor's quadrature mixer. The experimental results of displacement and velocity measurement are presented as a way to demonstrate the sensing ability of the RF interferometry and to illustrate its many possible applications in sensing. The book is succinct, ye...
Paraxial Green's functions in synchrotron radiation theory
International Nuclear Information System (INIS)
Geloni, G.; Saldin, E.; Scheidmiller, E.; Yurkov, M.
2005-02-01
This work contains a systematic treatment of single particle synchrotron radiation and some application to realistic beams with given cross section area, divergence and energy spread. Standard theory relies on several approximations whose applicability limits and accuracy are often forgotten. We begin remarking that on the one hand, a paraxial approximation can always be applied without loss of generality and with ultra relativistic accuracy. On the other hand, dominance of the acceleration field over the velocity part in the Lienard-Wiechert expressions is not always guaranteed and constitutes a separate assumption, whose applicability is discussed. Treating synchrotron radiation in paraxial approximation we derive the equation for the slow varying envelope function of the Fourier components of the electric field vector. Calculations of Synchrotron Radiation properties performed by others showed that the phase of the Fourier components of the electric field vector differs from the phase of a virtual point source. In this paper we present a systematic, analytical description of this phase shift, calculating amplitude and phase of electric field from bending magnets, short magnets, two bending magnet system separated by a straight section (edge radiation) and undulator devices. We pay particular attention to region of applicability and accuracy of approximations used. Finally, taking advantage of results of analytical calculation presented in reduced form we analyze various features of radiation from a complex insertion device (set of two undulators with a focusing triplet in between) accounting for the influence of energy spread and electron beam emittance. (orig.)
Directory of Open Access Journals (Sweden)
Zhifeng Zhong
2017-01-01
Full Text Available Owing to the environment, temperature, and so forth, photovoltaic power generation volume is always fluctuating and subsequently impacts power grid planning and operation seriously. Therefore, it is of great importance to make accurate prediction of the power generation of photovoltaic (PV system in advance. In order to improve the prediction accuracy, in this paper, a novel particle swarm optimization algorithm based multivariable grey theory model is proposed for short-term photovoltaic power generation volume forecasting. It is highlighted that, by integrating particle swarm optimization algorithm, the prediction accuracy of grey theory model is expected to be highly improved. In addition, large amounts of real data from two separate power stations in China are being employed for model verification. The experimental results indicate that, compared with the conventional grey model, the mean relative error in the proposed model has been reduced from 7.14% to 3.53%. The real practice demonstrates that the proposed optimization model outperforms the conventional grey model from both theoretical and practical perspectives.
Lin, Fen-Fang; Wang, Ke; Yang, Ning; Yan, Shi-Guang; Zheng, Xin-Yu
2012-02-01
In this paper, some main factors such as soil type, land use pattern, lithology type, topography, road, and industry type that affect soil quality were used to precisely obtain the spatial distribution characteristics of regional soil quality, mutual information theory was adopted to select the main environmental factors, and decision tree algorithm See 5.0 was applied to predict the grade of regional soil quality. The main factors affecting regional soil quality were soil type, land use, lithology type, distance to town, distance to water area, altitude, distance to road, and distance to industrial land. The prediction accuracy of the decision tree model with the variables selected by mutual information was obviously higher than that of the model with all variables, and, for the former model, whether of decision tree or of decision rule, its prediction accuracy was all higher than 80%. Based on the continuous and categorical data, the method of mutual information theory integrated with decision tree could not only reduce the number of input parameters for decision tree algorithm, but also predict and assess regional soil quality effectively.
Fission barrier theory and its application to the calculation of actinide neutron cross-sections
International Nuclear Information System (INIS)
Lynn, J.E.
1980-01-01
The lectures discuss the possibilities and realisations of applying nuclear fission theory to the calculation of unknown nuclear data required for applications, principally in the nuclear power field. A brief description of the fundamentals of fission theory, the nature of the potential energy surface in the deformation plane, and of the inertial tensor, is given, and the accuracy of the theoretical calculations is discussed. It is concluded that it is impracticable to obtain required quantities such as neutron cross-sections from such fundamental calculations at present. On the other hand the fundamental theory reveals a wealth of phenomenological aspects of the fission process which can be incorporated into nuclear reaction theory. It is then shown how reaction theory thus extended to take correct account of the structured (''double-humped'') fission barrier can be used to parametrise the barrier by analysis of experimental data, and subsequently to calculate new data. Descriptions of computer programmes and illustrations of the application of the methods to actual physical examples are included in this account. (author)
Quality of reporting of diagnostic accuracy studies
Smidt, N.; Rutjes, A.W.; Windt - Mens, van der D.A.W.M.; Ostelo, R.W.J.G.; Reitsma, J.B.; Bouter, L.M.; Vet, de H.C.W.
2005-01-01
PURPOSE: To evaluate quality of reporting in diagnostic accuracy articles published in 2000 in journals with impact factor of at least 4 by using items of Standards for Reporting of Diagnostic Accuracy (STARD) statement published later in 2003. MATERIALS AND METHODS: English-language articles on
On the convergence and accuracy of the FDTD method for nanoplasmonics.
Lesina, Antonino Calà; Vaccari, Alessandro; Berini, Pierre; Ramunno, Lora
2015-04-20
Use of the Finite-Difference Time-Domain (FDTD) method to model nanoplasmonic structures continues to rise - more than 2700 papers have been published in 2014 on FDTD simulations of surface plasmons. However, a comprehensive study on the convergence and accuracy of the method for nanoplasmonic structures has yet to be reported. Although the method may be well-established in other areas of electromagnetics, the peculiarities of nanoplasmonic problems are such that a targeted study on convergence and accuracy is required. The availability of a high-performance computing system (a massively parallel IBM Blue Gene/Q) allows us to do this for the first time. We consider gold and silver at optical wavelengths along with three "standard" nanoplasmonic structures: a metal sphere, a metal dipole antenna and a metal bowtie antenna - for the first structure comparisons with the analytical extinction, scattering, and absorption coefficients based on Mie theory are possible. We consider different ways to set-up the simulation domain, we vary the mesh size to very small dimensions, we compare the simple Drude model with the Drude model augmented with two critical points correction, we compare single-precision to double-precision arithmetic, and we compare two staircase meshing techniques, per-component and uniform. We find that the Drude model with two critical points correction (at least) must be used in general. Double-precision arithmetic is needed to avoid round-off errors if highly converged results are sought. Per-component meshing increases the accuracy when complex geometries are modeled, but the uniform mesh works better for structures completely fillable by the Yee cell (e.g., rectangular structures). Generally, a mesh size of 0.25 nm is required to achieve convergence of results to ∼ 1%. We determine how to optimally setup the simulation domain, and in so doing we find that performing scattering calculations within the near-field does not necessarily produces large
Comparison of a Vessel Sealing System with a Conventional Technique in Hemorrhoidectomy
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Serkan Teksöz
2011-06-01
Full Text Available Objective: Milligan-Morgan, Park and Ferguson hemorrhoidectomy procedures are the ones most frequently used for the surgical treatment of hemorrhoidal disease. Attempts to modify these conventional approaches are made by using different techniques or tools to decrease blood loss, and reduce operating time and postoperative analgesic requirement. In this prospective randomized trial, the conventional Ferguson hemorrhoidectomy method is compared with the LigaSure® hemorrhoidectomy according to various criteria. Material and Methods: Forty patients who had grade 3-4 hemorrhoidal disease were randomly divided into two equal groups: the Ferguson Hemorrhoidectomy (n=20 and the LigaSure® hemorrhoidectomy (n=20. Operating time, demographic data, intraoperative and postoperative complications, postoperative pain, return of bowel movements and postoperative hospital stay were evaluated. The visual analogue score was used for the evaluation of pain on the first postoperative day. The patients have been followed up for at least 19 months. Results: The pain score, blood loss and operating time were significantly reduced in the LigaSure® hemorrhoidectomy group. Conclusion: LigaSure® hemorrhoidectomy is safe and feasible for the surgeon, and more comfortable than classical surgery for the patient.
Singh, Vijai; Somvanshi, Pallavi
2010-02-01
DNA ligase is an important enzyme and it plays vital role in the replication and repair; also catalyzes nick joining between adjacent bases of DNA. The NAD(+) dependent DNA ligase is selectively present in eubacteria and few viruses; but missing in humans. Homology modeling was used to generate 3-D structure of NAD(+) dependent DNA ligase (LigA) of Mycobacterium tuberculosis using the known template (PDB: 2OWO). Furthermore, the stereochemical quality and torsion angle of 3-D structure was validated. Numerous effective drugs were selected and the active amino acid residue in LigA was targeted and virtual screening through molecular docking was done. In this analysis, four drugs Chloroquine, Hydroxychloroquine, Putrienscine and Adriamycin were found more potent in inhibition of M. tuberculosis through the robust binding affinity between protein-drug interactions in comparison with the other studied drugs. A phylogenetic tree was constructed and it was observed that homology of LigA in M. tuberculosis resembled with other Mycobacterium species. The conserved active amino acids of LigA may be useful to target these drugs. These findings could be used as the starting point of a rational design of novel antibacterial drugs and its analogs.
Analysis of spatial distribution of land cover maps accuracy
Khatami, R.; Mountrakis, G.; Stehman, S. V.
2017-12-01
Land cover maps have become one of the most important products of remote sensing science. However, classification errors will exist in any classified map and affect the reliability of subsequent map usage. Moreover, classification accuracy often varies over different regions of a classified map. These variations of accuracy will affect the reliability of subsequent analyses of different regions based on the classified maps. The traditional approach of map accuracy assessment based on an error matrix does not capture the spatial variation in classification accuracy. Here, per-pixel accuracy prediction methods are proposed based on interpolating accuracy values from a test sample to produce wall-to-wall accuracy maps. Different accuracy prediction methods were developed based on four factors: predictive domain (spatial versus spectral), interpolation function (constant, linear, Gaussian, and logistic), incorporation of class information (interpolating each class separately versus grouping them together), and sample size. Incorporation of spectral domain as explanatory feature spaces of classification accuracy interpolation was done for the first time in this research. Performance of the prediction methods was evaluated using 26 test blocks, with 10 km × 10 km dimensions, dispersed throughout the United States. The performance of the predictions was evaluated using the area under the curve (AUC) of the receiver operating characteristic. Relative to existing accuracy prediction methods, our proposed methods resulted in improvements of AUC of 0.15 or greater. Evaluation of the four factors comprising the accuracy prediction methods demonstrated that: i) interpolations should be done separately for each class instead of grouping all classes together; ii) if an all-classes approach is used, the spectral domain will result in substantially greater AUC than the spatial domain; iii) for the smaller sample size and per-class predictions, the spectral and spatial domain
Matter power spectrum and the challenge of percent accuracy
International Nuclear Information System (INIS)
Schneider, Aurel; Teyssier, Romain; Potter, Doug; Stadel, Joachim; Reed, Darren S.; Onions, Julian; Pearce, Frazer R.; Smith, Robert E.; Springel, Volker; Scoccimarro, Roman
2016-01-01
Future galaxy surveys require one percent precision in the theoretical knowledge of the power spectrum over a large range including very nonlinear scales. While this level of accuracy is easily obtained in the linear regime with perturbation theory, it represents a serious challenge for small scales where numerical simulations are required. In this paper we quantify the precision of present-day N -body methods, identifying main potential error sources from the set-up of initial conditions to the measurement of the final power spectrum. We directly compare three widely used N -body codes, Ramses, Pkdgrav3, and Gadget3 which represent three main discretisation techniques: the particle-mesh method, the tree method, and a hybrid combination of the two. For standard run parameters, the codes agree to within one percent at k ≤1 h Mpc −1 and to within three percent at k ≤10 h Mpc −1 . We also consider the bispectrum and show that the reduced bispectra agree at the sub-percent level for k ≤ 2 h Mpc −1 . In a second step, we quantify potential errors due to initial conditions, box size, and resolution using an extended suite of simulations performed with our fastest code Pkdgrav3. We demonstrate that the simulation box size should not be smaller than L =0.5 h −1 Gpc to avoid systematic finite-volume effects (while much larger boxes are required to beat down the statistical sample variance). Furthermore, a maximum particle mass of M p =10 9 h −1 M ⊙ is required to conservatively obtain one percent precision of the matter power spectrum. As a consequence, numerical simulations covering large survey volumes of upcoming missions such as DES, LSST, and Euclid will need more than a trillion particles to reproduce clustering properties at the targeted accuracy.
High accuracy FIONA-AFM hybrid imaging
International Nuclear Information System (INIS)
Fronczek, D.N.; Quammen, C.; Wang, H.; Kisker, C.; Superfine, R.; Taylor, R.; Erie, D.A.; Tessmer, I.
2011-01-01
Multi-protein complexes are ubiquitous and play essential roles in many biological mechanisms. Single molecule imaging techniques such as electron microscopy (EM) and atomic force microscopy (AFM) are powerful methods for characterizing the structural properties of multi-protein and multi-protein-DNA complexes. However, a significant limitation to these techniques is the ability to distinguish different proteins from one another. Here, we combine high resolution fluorescence microscopy and AFM (FIONA-AFM) to allow the identification of different proteins in such complexes. Using quantum dots as fiducial markers in addition to fluorescently labeled proteins, we are able to align fluorescence and AFM information to ≥8 nm accuracy. This accuracy is sufficient to identify individual fluorescently labeled proteins in most multi-protein complexes. We investigate the limitations of localization precision and accuracy in fluorescence and AFM images separately and their effects on the overall registration accuracy of FIONA-AFM hybrid images. This combination of the two orthogonal techniques (FIONA and AFM) opens a wide spectrum of possible applications to the study of protein interactions, because AFM can yield high resolution (5-10 nm) information about the conformational properties of multi-protein complexes and the fluorescence can indicate spatial relationships of the proteins in the complexes. -- Research highlights: → Integration of fluorescent signals in AFM topography with high (<10 nm) accuracy. → Investigation of limitations and quantitative analysis of fluorescence-AFM image registration using quantum dots. → Fluorescence center tracking and display as localization probability distributions in AFM topography (FIONA-AFM). → Application of FIONA-AFM to a biological sample containing damaged DNA and the DNA repair proteins UvrA and UvrB conjugated to quantum dots.
Audiovisual biofeedback improves motion prediction accuracy.
Pollock, Sean; Lee, Danny; Keall, Paul; Kim, Taeho
2013-04-01
The accuracy of motion prediction, utilized to overcome the system latency of motion management radiotherapy systems, is hampered by irregularities present in the patients' respiratory pattern. Audiovisual (AV) biofeedback has been shown to reduce respiratory irregularities. The aim of this study was to test the hypothesis that AV biofeedback improves the accuracy of motion prediction. An AV biofeedback system combined with real-time respiratory data acquisition and MR images were implemented in this project. One-dimensional respiratory data from (1) the abdominal wall (30 Hz) and (2) the thoracic diaphragm (5 Hz) were obtained from 15 healthy human subjects across 30 studies. The subjects were required to breathe with and without the guidance of AV biofeedback during each study. The obtained respiratory signals were then implemented in a kernel density estimation prediction algorithm. For each of the 30 studies, five different prediction times ranging from 50 to 1400 ms were tested (150 predictions performed). Prediction error was quantified as the root mean square error (RMSE); the RMSE was calculated from the difference between the real and predicted respiratory data. The statistical significance of the prediction results was determined by the Student's t-test. Prediction accuracy was considerably improved by the implementation of AV biofeedback. Of the 150 respiratory predictions performed, prediction accuracy was improved 69% (103/150) of the time for abdominal wall data, and 78% (117/150) of the time for diaphragm data. The average reduction in RMSE due to AV biofeedback over unguided respiration was 26% (p biofeedback improves prediction accuracy. This would result in increased efficiency of motion management techniques affected by system latencies used in radiotherapy.
Idéias e política externa: a atuação brasileira na Liga das Nações e na ONU
Directory of Open Access Journals (Sweden)
Alexandra de Mello e Silva
1998-12-01
Full Text Available Esse artigo apresenta uma proposta de análise da influência de idéias sobre a formulação da política externa brasileira contemporânea focalizada em nossa atuação na Liga das Nações e na ONU. Em ambos os organismos, o país desenvolveu aspirações a um papel internacional protagônico, o que acreditamos ser indicador da recorrência, no discurso diplomático, de certas crenças a respeito de quais devam ser o nosso papel, status e pertencimento a nível internacional. Destacamos, ao mesmo tempo, que uma análise desse tipo não pode se limitar a reconstruir o discurso diplomático, mas deve também procurar desvendar os mecanismos causais que explicam o impacto daquelas crenças sobre a formação de políticas. Nesse sentido, a literatura acadêmica internacional já desenvolveu uma série de abordagens que podem se revelar úteis para um estudo da diplomacia brasileira.This article presents an analytical framework of the influence of ideas over Brazilian contemporary foreign policy formulation, focusing on Brazilian performance at the League of Nations and the United Nations. In both organizations, Brazil has aspired to perform an international leading role, which, as we argue, constitutes an indicator of the recurrence, in the diplomatic discourse, of certain beliefs about what should be Brazilian status, role and belonging in the international arena. Simultaneously, the article argues that such analysis should not only reconstruct the diplomatic discourse but also try to unfold the causal mechanisms that explain the impact of those beliefs in the policymaking process. In this sense, the international academic literature has already developed a series of approaches that might prove useful to the study of Brazilian diplomacy.
Morgenstern e a exatidão dos dados contábeis = Morgenstern and the accuracy of accouting data
Directory of Open Access Journals (Sweden)
Nelson Hein
2010-01-01
Full Text Available O trabalho discorre essencialmente sobre a noção de erro, fazendo um estudo detalhado decomo o erro é tratado nas ciências e analisa a fidedignidade dos dados nas ciências contábeis.Por objetivos tem-se: apontar, analisar e avaliar os problemas estatísticos entre as relações dateoria econômica e a teoria da contabilidade, que “grosso modo”, geram conflitos, devido a ruídosentre as duas áreas e que podem ser minimizados no futuro, considerando a exatidão dos dadosna origem estatística do fenômeno. Sua fundamentação é lastreada no trabalho original deMorgenstern, On the Accuracy of Economic Observation, no qual o pesquisador aborda o tema,em uma visão de meados do século XX. O artigo preconiza sobre a importância dodesenvolvimento de uma teoria estatística capaz de tratar a situação com presença de erro, ouseja, no uso de uma mescla ordenada ou série de cifras com conjectura e estimações decrescente incerteza. Esta série não é fortuita, senão, que possua suas próprias regras,convenções e certa quantidade de estabilidade. A agregação de tais cifras, produziria certamedida de informação, ainda que não como se imagina correntemente. O trabalho concluiavaliando que os negócios tramitam na ilusão de se tratarem de dados exatos nos quais não háexatidão, em sentido ordinário e científico. Nem existe uma noção que possa ser substituída eisto tem profunda significação a julgar pelas possibilidades, e os efeitos nas políticas, emprevisões e sem dúvida da importância primordial na teoria contábil.The paper work discourses mainly on the notion of error, making a detailed study of how the error is handledin science and examines the reliability of data accounting in the sciences. As purposes, it presents: to point,to analyse, and to evaluate the statistical problems of the relations between economical theory andaccounting theory, which, in geral, generate conflicts due to noises between the two areas
1996-06-01
switches 5-43 Figure 5-27. Mechanical interference between ’Pull Spring’ devices 5-45 Figure 5-28. Array of LIGA mechanical relay switches 5-49...like coating DM Direct metal interconnect technique DMD ™ Digital Micromirror Device EDP Ethylene, diamine, pyrocatechol and water; silicon anisotropic...mechanical systems MOSIS MOS Implementation Service PGA Pin grid array, an electronic die package PZT Lead-zirconate-titanate LIGA Lithographie
Building an Evaluation Scale using Item Response Theory.
Lalor, John P; Wu, Hao; Yu, Hong
2016-11-01
Evaluation of NLP methods requires testing against a previously vetted gold-standard test set and reporting standard metrics (accuracy/precision/recall/F1). The current assumption is that all items in a given test set are equal with regards to difficulty and discriminating power. We propose Item Response Theory (IRT) from psychometrics as an alternative means for gold-standard test-set generation and NLP system evaluation. IRT is able to describe characteristics of individual items - their difficulty and discriminating power - and can account for these characteristics in its estimation of human intelligence or ability for an NLP task. In this paper, we demonstrate IRT by generating a gold-standard test set for Recognizing Textual Entailment. By collecting a large number of human responses and fitting our IRT model, we show that our IRT model compares NLP systems with the performance in a human population and is able to provide more insight into system performance than standard evaluation metrics. We show that a high accuracy score does not always imply a high IRT score, which depends on the item characteristics and the response pattern.
International Nuclear Information System (INIS)
Moss, R.L.
1977-10-01
A wrapper face is assumed to be a long, narrow, rectangular plate. The mechanical interaction between adjacent dilating wrappers in contact along an axial line is discussed in terms of the theory of the bending of plates. A variational method is used to obtain neat and concise equations that determine both the interaction load and the length of the line of contact. The prime objective of the work is to compare the results obtained from plate theory with corresponding expressions from much simpler calculations based on beam theory. Numerical results indicate that the elastic dilation of a wrapper and its interaction with a neighbouring wrapper can be calculated to adequate accuracy by simple beam theory. (author)
Intelligence: Pre-Theory and Post-Theory
Directory of Open Access Journals (Sweden)
James R. Flynn
2014-02-01
Full Text Available Defining “intelligence” exemplifies a mistake that has historical precedent: confusing the role of pre-theory and post-theory definitions. In every area, pre-theory concepts give broad directions for investigation: are the movements of heavenly bodies affected by the existence of other heavenly bodies? Post-theory concepts add precision and predictability. The mistake occurs when a successful theory like Newton’s demands that its peculiar and precise theory-imbedded concept forbids competing theories: Einstein was impossible (warping of space so long as it was assumed that all theories must be in accord with Newton’s concept (attraction across space. In psychology, Arthur Jensen made the same mistake. He gave his theory-embedded concept of g the role of executioner: the significance of every phenomenon had to be interpreted by its compatibility with g; and thus trivialized the significance of IQ gains over time. This is only one instance of a perennial demand: give us a precise definition of “intelligence” to guide our research. However, precision comes after research has generated a theory and its very precision stifles competing research. Be happy with a broad definition on the pre-theory level that lets many competing theories bloom: pre-theory precision equals post-theory poverty.
Accuracy of Parent Identification of Stuttering Occurrence
Einarsdottir, Johanna; Ingham, Roger
2009-01-01
Background: Clinicians rely on parents to provide information regarding the onset and development of stuttering in their own children. The accuracy and reliability of their judgments of stuttering is therefore important and is not well researched. Aim: To investigate the accuracy of parent judgements of stuttering in their own children's speech…
Smith, Zachary J; Chu, Kaiqin; Wachsmann-Hogiu, Sebastian
2012-01-01
We report on the construction of a Fourier plane imaging system attached to a cell phone. By illuminating particle suspensions with a collimated beam from an inexpensive diode laser, angularly resolved scattering patterns are imaged by the phone's camera. Analyzing these patterns with Mie theory results in predictions of size distributions of the particles in suspension. Despite using consumer grade electronics, we extracted size distributions of sphere suspensions with better than 20 nm accuracy in determining the mean size. We also show results from milk, yeast, and blood cells. Performing these measurements on a portable device presents opportunities for field-testing of food quality, process monitoring, and medical diagnosis.
Reliability and accuracy of Crystaleye spectrophotometric system.
Chen, Li; Tan, Jian Guo; Zhou, Jian Feng; Yang, Xu; Du, Yang; Wang, Fang Ping
2010-01-01
to develop an in vitro shade-measuring model to evaluate the reliability and accuracy of the Crystaleye spectrophotometric system, a newly developed spectrophotometer. four shade guides, VITA Classical, VITA 3D-Master, Chromascop and Vintage Halo NCC, were measured with the Crystaleye spectrophotometer in a standardised model, ten times for 107 shade tabs. The shade-matching results and the CIE L*a*b* values of the cervical, body and incisal regions for each measurement were automatically analysed using the supporting software. Reliability and accuracy were calculated for each shade tab both in percentage and in colour difference (ΔE). Difference was analysed by one-way ANOVA in the cervical, body and incisal regions. range of reliability was 88.81% to 98.97% and 0.13 to 0.24 ΔE units, and that of accuracy was 44.05% to 91.25% and 1.03 to 1.89 ΔE units. Significant differences in reliability and accuracy were found between the body region and the cervical and incisal regions. Comparisons made among regions and shade guides revealed that evaluation in ΔE was prone to disclose the differences. measurements with the Crystaleye spectrophotometer had similar, high reliability in different shade guides and regions, indicating predictable repeated measurements. Accuracy in the body region was high and less variable compared with the cervical and incisal regions.
Social class, contextualism, and empathic accuracy.
Kraus, Michael W; Côté, Stéphane; Keltner, Dacher
2010-11-01
Recent research suggests that lower-class individuals favor explanations of personal and political outcomes that are oriented to features of the external environment. We extended this work by testing the hypothesis that, as a result, individuals of a lower social class are more empathically accurate in judging the emotions of other people. In three studies, lower-class individuals (compared with upper-class individuals) received higher scores on a test of empathic accuracy (Study 1), judged the emotions of an interaction partner more accurately (Study 2), and made more accurate inferences about emotion from static images of muscle movements in the eyes (Study 3). Moreover, the association between social class and empathic accuracy was explained by the tendency for lower-class individuals to explain social events in terms of features of the external environment. The implications of class-based patterns in empathic accuracy for well-being and relationship outcomes are discussed.
Koopman, Richelle J; Kochendorfer, Karl M; Moore, Joi L; Mehr, David R; Wakefield, Douglas S; Yadamsuren, Borchuluun; Coberly, Jared S; Kruse, Robin L; Wakefield, Bonnie J; Belden, Jeffery L
2011-01-01
We compared use of a new diabetes dashboard screen with use of a conventional approach of viewing multiple electronic health record (EHR) screens to find data needed for ambulatory diabetes care. We performed a usability study, including a quantitative time study and qualitative analysis of information-seeking behaviors. While being recorded with Morae Recorder software and "think-aloud" interview methods, 10 primary care physicians first searched their EHR for 10 diabetes data elements using a conventional approach for a simulated patient, and then using a new diabetes dashboard for another. We measured time, number of mouse clicks, and accuracy. Two coders analyzed think-aloud and interview data using grounded theory methodology. The mean time needed to find all data elements was 5.5 minutes using the conventional approach vs 1.3 minutes using the diabetes dashboard (P dashboard (P dashboard (P dashboard improves both the efficiency and accuracy of acquiring data needed for high-quality diabetes care. Usability analysis tools can provide important insights into the value of optimizing physician use of health information technologies.
12 CFR 740.2 - Accuracy of advertising.
2010-01-01
... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Accuracy of advertising. 740.2 Section 740.2... ADVERTISING AND NOTICE OF INSURED STATUS § 740.2 Accuracy of advertising. No insured credit union may use any advertising (which includes print, electronic, or broadcast media, displays and signs, stationery, and other...
Diagnostic accuracy of MRCP in choledocholithiasis
International Nuclear Information System (INIS)
Guarise, Alessandro; Mainardi, Paride; Baltieri, Susanna; Faccioli, Niccolo'
2005-01-01
Purpose: To evaluate the accuracy of MRCP in diagnosing choledocholithiasis considering Endoscopic Retrograde Cholangiopancreatography (ERCP) as the gold standard. To compare the results achieved during the first two years of use (1999-2000) of Magnetic Resonance Cholangiopancreatography (MRCP) in patients with suspected choledocholithiasis with those achieved during the following two years (2001-2002) in order to establish the repeatability and objectivity of MRCP results. Materials and methods: One hundred and seventy consecutive patients underwent MRCP followed by ERCP within 72 h. In 22/170 (13%) patients ERCP was unsuccessful for different reasons. MRCP was performed using a 1.5 T magnet with both multi-slice HASTE sequences and thick-slice projection technique. Choledocholithiasis was diagnosed in the presence of signal void images in the dependent portion of the duct surrounded by hyperintense bile and detected at least in two projections. The MRCP results, read independently from the ERCP results, were compared in two different and subsequent periods. Results: ERCP confirmed choledocholithiasis in 87 patients. In these cases the results of MRCP were the following: 78 true positives, 53 true negatives, 7 false positives, and 9 false negatives. The sensitivity, specificity and accuracy were 90%, 88% and 89%, respectively. After the exclusion of stones with diameters smaller than 6 mm, the sensitivity, specificity and accuracy were 100%, 99% and 99%, respectively. MRCP accuracy was related to the size of the stones. There was no significant statistical difference between the results obtained in the first two-year period and those obtained in the second period. Conclusions: MRCP i sufficiently accurate to replace ERCP in patients with suspected choledocholithiasis. The results are related to the size of stones. The use of well-defined radiological signs allows good diagnostic accuracy independent of the learning curve [it
Meissner, Christian A; Tredoux, Colin G; Parker, Janat F; MacLin, Otto H
2005-07-01
Many eyewitness researchers have argued for the application of a sequential alternative to the traditional simultaneous lineup, given its role in decreasing false identifications of innocent suspects (sequential superiority effect). However, Ebbesen and Flowe (2002) have recently noted that sequential lineups may merely bring about a shift in response criterion, having no effect on discrimination accuracy. We explored this claim, using a method that allows signal detection theory measures to be collected from eyewitnesses. In three experiments, lineup type was factorially combined with conditions expected to influence response criterion and/or discrimination accuracy. Results were consistent with signal detection theory predictions, including that of a conservative criterion shift with the sequential presentation of lineups. In a fourth experiment, we explored the phenomenological basis for the criterion shift, using the remember-know-guess procedure. In accord with previous research, the criterion shift in sequential lineups was associated with a reduction in familiarity-based responding. It is proposed that the relative similarity between lineup members may create a context in which fluency-based processing is facilitated to a greater extent when lineup members are presented simultaneously.
[Navigation in implantology: Accuracy assessment regarding the literature].
Barrak, Ibrahim Ádám; Varga, Endre; Piffko, József
2016-06-01
Our objective was to assess the literature regarding the accuracy of the different static guided systems. After applying electronic literature search we found 661 articles. After reviewing 139 articles, the authors chose 52 articles for full-text evaluation. 24 studies involved accuracy measurements. Fourteen of our selected references were clinical and ten of them were in vitro (modell or cadaver). Variance-analysis (Tukey's post-hoc test; p angular deviation was 3,96 degrees. Significant difference could be observed between the two methods of implant placement (partially and fully guided sequence) in terms of deviation at the entry point, apex and angular deviation. Different levels of quality and quantity of evidence were available for assessing the accuracy of the different computer-assisted implant placement. The rapidly evolving field of digital dentistry and the new developments will further improve the accuracy of guided implant placement. In the interest of being able to draw dependable conclusions and for the further evaluation of the parameters used for accuracy measurements, randomized, controlled single or multi-centered clinical trials are necessary.
Application of preprocessing filtering on Decision Tree C4.5 and rough set theory
Chan, Joseph C. C.; Lin, Tsau Y.
2001-03-01
This paper compares two artificial intelligence methods: the Decision Tree C4.5 and Rough Set Theory on the stock market data. The Decision Tree C4.5 is reviewed with the Rough Set Theory. An enhanced window application is developed to facilitate the pre-processing filtering by introducing the feature (attribute) transformations, which allows users to input formulas and create new attributes. Also, the application produces three varieties of data set with delaying, averaging, and summation. The results prove the improvement of pre-processing by applying feature (attribute) transformations on Decision Tree C4.5. Moreover, the comparison between Decision Tree C4.5 and Rough Set Theory is based on the clarity, automation, accuracy, dimensionality, raw data, and speed, which is supported by the rules sets generated by both algorithms on three different sets of data.
Directory of Open Access Journals (Sweden)
Fábio Fernandes Neves
2010-02-01
Full Text Available INTRODUÇÃO: a hiporretinolemia constitui fator prognóstico independente em pacientes com AIDS, e a atividade inflamatória causa redução dos níveis séricos deste nutriente na população em geral. Entretanto, faltam estudos que avaliem o impacto da atividade inflamatória sobre o nível sérico do retinol em pacientes com AIDS. MÉTODOS: foram avaliados transversalmente 41 pacientes internados por complicações da AIDS, que tiveram quantificados alguns marcadores de inflamação (proteína C reativa e fator de necrose tumoral alfa e concentrações séricas de retinol e da proteína de ligação do retinol. RESULTADOS: apesar da baixa (14,6% prevalência de hiporretinolemia evidenciou-se correlação negativa dos marcadores de inflamação com os níveis séricos de retinol e de sua proteína de ligação nos pacientes com AIDS. CONCLUSÕES: a atividade inflamatória de fase aguda está associada a baixos níveis séricos de retinol em indivíduos com AIDS.INTRODUCTION: Hyporetinolemia is an independent prognostic factor in AIDS patients. Inflammatory activity causes a reduction in the serum levels of this nutrient in the general population. However, there are no studies assessing the impact of inflammatory activity on the serum retinol level in AIDS patients. METHODS: A cross-sectional assessment was conducted on 41 patients hospitalized due to AIDS complications. Inflammatory markers (C-reactive protein and tumor necrosis factor-alpha and serum retinol and retinol binding protein concentrations were quantified. RESULTS: Despite the low (14.6% prevalence of hyporetinolemia, a significant negative correlation was observed between the inflammatory markers and the serum retinol and retinol binding protein levels in AIDS patients. CONCLUSIONS: Acute-phase inflammatory activity is associated with low serum retinol levels in individuals with AIDS.
Ward, Roslyn; Leitão, Suze; Strauss, Geoff
2014-08-01
This study evaluates perceptual changes in speech production accuracy in six children (3-11 years) with moderate-to-severe speech impairment associated with cerebral palsy before, during, and after participation in a motor-speech intervention program (Prompts for Restructuring Oral Muscular Phonetic Targets). An A1BCA2 single subject research design was implemented. Subsequent to the baseline phase (phase A1), phase B targeted each participant's first intervention priority on the PROMPT motor-speech hierarchy. Phase C then targeted one level higher. Weekly speech probes were administered, containing trained and untrained words at the two levels of intervention, plus an additional level that served as a control goal. The speech probes were analysed for motor-speech-movement-parameters and perceptual accuracy. Analysis of the speech probe data showed all participants recorded a statistically significant change. Between phases A1-B and B-C 6/6 and 4/6 participants, respectively, recorded a statistically significant increase in performance level on the motor speech movement patterns targeted during the training of that intervention. The preliminary data presented in this study make a contribution to providing evidence that supports the use of a treatment approach aligned with dynamic systems theory to improve the motor-speech movement patterns and speech production accuracy in children with cerebral palsy.
Electronic structure theory of the superheavy elements
Energy Technology Data Exchange (ETDEWEB)
Eliav, Ephraim, E-mail: ephraim@tau.ac.il [School of Chemistry, Tel Aviv University, 6997801 Tel Aviv (Israel); Fritzsche, Stephan, E-mail: s.fritzsche@gsi.de [Helmholtz-Institut Jena, Fröbelstieg 3, D-07743 Jena (Germany); Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena, D-07743 Jena (Germany); Kaldor, Uzi, E-mail: kaldor@tau.ac.il [School of Chemistry, Tel Aviv University, 6997801 Tel Aviv (Israel)
2015-12-15
High-accuracy calculations of atomic properties of the superheavy elements (SHE) up to element 122 are reviewed. The properties discussed include ionization potentials, electron affinities and excitation energies, which are associated with the spectroscopic and chemical behavior of these elements, and are therefore of considerable interest. Accurate predictions of these quantities require high-order inclusion of relativity and electron correlation, as well as large, converged basis sets. The Dirac–Coulomb–Breit Hamiltonian, which includes all terms up to second order in the fine-structure constant α, serves as the framework for the treatment; higher-order Lamb shift terms are considered in some selected cases. Electron correlation is treated by either the multiconfiguration self-consistent-field approach or by Fock-space coupled cluster theory. The latter is enhanced by the intermediate Hamiltonian scheme, allowing the use of larger model (P) spaces. The quality of the calculations is assessed by applying the same methods to lighter homologs of the SHEs and comparing with available experimental information. Very good agreement is obtained, within a few hundredths of an eV, and similar accuracy is expected for the SHEs. Many of the properties predicted for the SHEs differ significantly from what may be expected by straightforward extrapolation of lighter homologs, demonstrating that the structure and chemistry of SHEs are strongly affected by relativity. The major scientific challenge of the calculations is to find the electronic structure and basic atomic properties of the SHE and assign its proper place in the periodic table. Significant recent developments include joint experimental–computational studies of the excitation spectrum of Fm and the ionization energy of Lr, with excellent agreement of experiment and theory, auguring well for the future of research in the field.
Studies on the diagnostic accuracy of lymphography
International Nuclear Information System (INIS)
Luening, M.; Stargardt, A.; Abet, L.
1979-01-01
Contradictory reports in the literature on the reliability of lymphography stimulated the authors to test the diagnostic accuracy, employing methods which are approximately analogous to practice, using carcinoma of the cervix as the model on which the study was carried out. Using 21 observers it was found that there was no correlation between their experience and on-target accuracy of the diagnosis. Good observers obtained an accuracy of 85% with good proportions between sensitivity in the recognition of detail, specificity and readiness to arrive at a decision on the basis of discriminatory ability. With the help of the concept of the ROC curves, the position taken up by the observers in respect of diagnostic decisions, and a complex manner of assessing the various characteristic factors determining diagnostic accuracy, are demonstrated. This form of test, which permits manipulation of different variants of diagnosis, is recommended, among other things, for performance control at the end of training and continuing education courses in other fields of x-ray diagnosis as well. (orig.) [de
Dragoni, Daniele; Daff, Thomas D.; Csányi, Gábor; Marzari, Nicola
2018-01-01
We show that the Gaussian Approximation Potential (GAP) machine-learning framework can describe complex magnetic potential energy surfaces, taking ferromagnetic iron as a paradigmatic challenging case. The training database includes total energies, forces, and stresses obtained from density-functional theory in the generalized-gradient approximation, and comprises approximately 150,000 local atomic environments, ranging from pristine and defected bulk configurations to surfaces and generalized stacking faults with different crystallographic orientations. We find the structural, vibrational, and thermodynamic properties of the GAP model to be in excellent agreement with those obtained directly from first-principles electronic-structure calculations. There is good transferability to quantities, such as Peierls energy barriers, which are determined to a large extent by atomic configurations that were not part of the training set. We observe the benefit and the need of using highly converged electronic-structure calculations to sample a target potential energy surface. The end result is a systematically improvable potential that can achieve the same accuracy of density-functional theory calculations, but at a fraction of the computational cost.
M-Theory and Maximally Supersymmetric Gauge Theories
Lambert, Neil
2012-01-01
In this informal review for non-specalists we discuss the construction of maximally supersymmetric gauge theories that arise on the worldvolumes branes in String Theory and M-Theory. Particular focus is made on the relatively recent construction of M2-brane worldvolume theories. In a formal sense, the existence of these quantum field theories can be viewed as predictions of M-Theory. Their construction is therefore a reinforcement of the ideas underlying String Theory and M-Theory. We also briefly discuss the six-dimensional conformal field theory that is expected to arise on M5-branes. The construction of this theory is not only an important open problem for M-Theory but also a significant challenge to our current understanding of quantum field theory more generally.
Increasing of AC compensation method accuracy
International Nuclear Information System (INIS)
Havlicek, V.; Pokorny, M.
2003-01-01
The original MMF compensation method allows the magnetic properties of single sheets and strips to be measured in the same way as the closed specimen properties. The accuracy of the method is limited due to the finite gain of the feedback loop fulfilling the condition of its stability. Digitalisation of the compensation loop appropriate processing of the error signal can rapidly improve the accuracy. The basic ideas of this new approach and the experimental results are described in this paper
Increasing of AC compensation method accuracy
Havlíček, V.; Pokorný, M.
2003-01-01
The original MMF compensation method allows the magnetic properties of single sheets and strips to be measured in the same way as the closed specimen properties. The accuracy of the method is limited due to the finite gain of the feedback loop fulfilling the condition of its stability. Digitalisation of the compensation loop appropriate processing of the error signal can rapidly improve the accuracy. The basic ideas of this new approach and the experimental results are described in this paper.
Electron ray tracing with high accuracy
International Nuclear Information System (INIS)
Saito, K.; Okubo, T.; Takamoto, K.; Uno, Y.; Kondo, M.
1986-01-01
An electron ray tracing program is developed to investigate the overall geometrical and chromatic aberrations in electron optical systems. The program also computes aberrations due to manufacturing errors in lenses and deflectors. Computation accuracy is improved by (1) calculating electrostatic and magnetic scalar potentials using the finite element method with third-order isoparametric elements, and (2) solving the modified ray equation which the aberrations satisfy. Computation accuracy of 4 nm is achieved for calculating optical properties of the system with an electrostatic lens
Clark, T Justin; ter Riet, Gerben; Coomarasamy, Aravinthan; Khan, Khalid S
2004-01-01
Abstract Background To empirically evaluate bias in estimation of accuracy associated with delay in verification of diagnosis among studies evaluating tests for predicting endometrial hyperplasia. Methods Systematic reviews of all published research on accuracy of miniature endometrial biopsy and endometr ial ultrasonography for diagnosing endometrial hyperplasia identified 27 test accuracy studies (2,982 subjects). Of these, 16 had immediate histological verification of diagnosis while 11 ha...
A review on the processing accuracy of two-photon polymerization
Directory of Open Access Journals (Sweden)
Xiaoqin Zhou
2015-03-01
Full Text Available Two-photon polymerization (TPP is a powerful and potential technology to fabricate true three-dimensional (3D micro/nanostructures of various materials with subdiffraction-limit resolution. And it has been applied to microoptics, electronics, communications, biomedicine, microfluidic devices, MEMS and metamaterials. These applications, such as microoptics and photon crystals, put forward rigorous requirements on the processing accuracy of TPP, including the dimensional accuracy, shape accuracy and surface roughness and the processing accuracy influences their performance, even invalidate them. In order to fabricate precise 3D micro/nanostructures, the factors influencing the processing accuracy need to be considered comprehensively and systematically. In this paper, we review the basis of TPP micro/nanofabrication, including mechanism of TPP, experimental set-up for TPP and scaling laws of resolution of TPP. Then, we discuss the factors influencing the processing accuracy. Finally, we summarize the methods reported lately to improve the processing accuracy from improving the resolution and changing spatial arrangement of voxels.
A review on the processing accuracy of two-photon polymerization
Energy Technology Data Exchange (ETDEWEB)
Zhou, Xiaoqin; Hou, Yihong [School of Mechanical Science and Engineering, Jilin University, Changchun, 130022 (China); Lin, Jieqiong, E-mail: linjieqiong@mail.ccut.edu.cn [School of Electromechanical Engineering, Changchun University of Technology, Changchun, 130012 (China)
2015-03-15
Two-photon polymerization (TPP) is a powerful and potential technology to fabricate true three-dimensional (3D) micro/nanostructures of various materials with subdiffraction-limit resolution. And it has been applied to microoptics, electronics, communications, biomedicine, microfluidic devices, MEMS and metamaterials. These applications, such as microoptics and photon crystals, put forward rigorous requirements on the processing accuracy of TPP, including the dimensional accuracy, shape accuracy and surface roughness and the processing accuracy influences their performance, even invalidate them. In order to fabricate precise 3D micro/nanostructures, the factors influencing the processing accuracy need to be considered comprehensively and systematically. In this paper, we review the basis of TPP micro/nanofabrication, including mechanism of TPP, experimental set-up for TPP and scaling laws of resolution of TPP. Then, we discuss the factors influencing the processing accuracy. Finally, we summarize the methods reported lately to improve the processing accuracy from improving the resolution and changing spatial arrangement of voxels.
Ultra-wideband ranging precision and accuracy
International Nuclear Information System (INIS)
MacGougan, Glenn; O'Keefe, Kyle; Klukas, Richard
2009-01-01
This paper provides an overview of ultra-wideband (UWB) in the context of ranging applications and assesses the precision and accuracy of UWB ranging from both a theoretical perspective and a practical perspective using real data. The paper begins with a brief history of UWB technology and the most current definition of what constitutes an UWB signal. The potential precision of UWB ranging is assessed using Cramer–Rao lower bound analysis. UWB ranging methods are described and potential error sources are discussed. Two types of commercially available UWB ranging radios are introduced which are used in testing. Actual ranging accuracy is assessed from line-of-sight testing under benign signal conditions by comparison to high-accuracy electronic distance measurements and to ranges derived from GPS real-time kinematic positioning. Range measurements obtained in outdoor testing with line-of-sight obstructions and strong reflection sources are compared to ranges derived from classically surveyed positions. The paper concludes with a discussion of the potential applications for UWB ranging
High accuracy magnetic field mapping of the LEP spectrometer magnet
Roncarolo, F
2000-01-01
The Large Electron Positron accelerator (LEP) is a storage ring which has been operated since 1989 at the European Laboratory for Particle Physics (CERN), located in the Geneva area. It is intended to experimentally verify the Standard Model theory and in particular to detect with high accuracy the mass of the electro-weak force bosons. Electrons and positrons are accelerated inside the LEP ring in opposite directions and forced to collide at four locations, once they reach an energy high enough for the experimental purposes. During head-to-head collisions the leptons loose all their energy and a huge amount of energy is concentrated in a small region. In this condition the energy is quickly converted in other particles which tend to go away from the interaction point. The higher the energy of the leptons before the collisions, the higher the mass of the particles that can escape. At LEP four large experimental detectors are accommodated. All detectors are multi purpose detectors covering a solid angle of alm...
On hypercharge flux and exotics in F-theory GUTs
Dudas, Emilian; 10.1007
2010-01-01
We study SU(5) Grand Unified Theories within a local framework in F-theory with multiple extra U(1) symmetries arising from a small monodromy group. The use of hypercharge flux for doublet-triplet splitting implies massless exotics in the spectrum that are protected from obtaining a mass by the U(1) symmetries. We find that lifting the exotics by giving vacuum expectation values to some GUT singlets spontaneously breaks all the U(1) symmetries which implies that proton decay operators are induced. If we impose an additional R-parity symmetry by hand we find all the exotics can be lifted while proton decay operators are still forbidden. These models can retain the gauge coupling unification accuracy of the MSSM at 1-loop. For models where the generations are distributed across multiple curves we also present a motivation for the quark-lepton mass splittings at the GUT scale based on a Froggatt-Nielsen approach to flavour.
Surface Water Quality Evaluation Based on a Game Theory-Based Cloud Model
Directory of Open Access Journals (Sweden)
Bing Yang
2018-04-01
Full Text Available Water quality evaluation is an essential measure to analyze water quality. However, excessive randomness and fuzziness affect the process of evaluation, thus reducing the accuracy of evaluation. Therefore, this study proposed a cloud model for evaluating the water quality to alleviate this problem. Analytic hierarchy process and entropy theory were used to calculate the subjective weight and objective weight, respectively, and then they were coupled as a combination weight (CW via game theory. The proposed game theory-based cloud model (GCM was then applied to the Qixinggang section of the Beijiang River. The results show that the CW ranks fecal coliform as the most important factor, followed by total nitrogen and total phosphorus, while biochemical oxygen demand and fluoride were considered least important. There were 19 months (31.67% at grade I, 39 months (65.00% at grade II, and one month at grade IV and grade V during 2010–2014. A total of 52 months (86.6% of GCM were identical to the comprehensive evaluation result (CER. The obtained water quality grades of GCM are close to the grades of the analytic hierarchy process weight (AHPW due to the weight coefficient of AHPW set to 0.7487. Generally, one or two grade gaps exist among the results of the three groups of weights, suggesting that the index weight is not particularly sensitive to the cloud model. The evaluated accuracy of water quality can be improved by modifying the quantitative boundaries. This study could provide a reference for water quality evaluation, prevention, and improvement of water quality assessment and other applications.
Gomes, Hilary; Barrett, Sophia; Duff, Martin; Barnhardt, Jack; Ritter, Walter
2008-03-01
We examined the impact of perceptual load by manipulating interstimulus interval (ISI) in two auditory selective attention studies that varied in the difficulty of the target discrimination. In the paradigm, channels were separated by frequency and target/deviant tones were softer in intensity. Three ISI conditions were presented: fast (300ms), medium (600ms) and slow (900ms). Behavioral (accuracy and RT) and electrophysiological measures (Nd, P3b) were observed. In both studies, participants evidenced poorer accuracy during the fast ISI condition than the slow suggesting that ISI impacted task difficulty. However, none of the three measures of processing examined, Nd amplitude, P3b amplitude elicited by unattended deviant stimuli, or false alarms to unattended deviants, were impacted by ISI in the manner predicted by perceptual load theory. The prediction based on perceptual load theory, that there would be more processing of irrelevant stimuli under conditions of low as compared to high perceptual load, was not supported in these auditory studies. Task difficulty/perceptual load impacts the processing of irrelevant stimuli in the auditory modality differently than predicted by perceptual load theory, and perhaps differently than in the visual modality.
Enhancing spoken connected-digit recognition accuracy by error ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
nition systems have gained acceptable accuracy levels, the accuracy of recognition of current connected ... bar code and ISBN1 library code to name a few. ..... Kopec G, Bush M 1985 Network-based connected-digit recognition. IEEE Trans.
Directory of Open Access Journals (Sweden)
Ketan Rathod
2018-01-01
Full Text Available Diagnosis of base of tongue malignancy can be obtained through clinical examination and biopsy. Magnetic Resonance Imaging (MRI and Computed Tomography (CT are used to detect its local extension, nodal spread and distant metastases. The main aim of study was to compare the accuracy of MRI and contrast enhanced CT in determining the local extent of base of tongue malignancy. Twenty five patients, biopsy proven cases of squamous cell carcinoma of base of tongue were taken. 1.5 Tesla Magnetic Resonance Unit with T2 weighted axial, coronal image; T1 weighted axial, coronal image; and STIR (Short tau inversion recovery axial and coronal images were used. 16 slice Computed Tomography unit with non-contrast and contrast enhanced images were used. Accuracy of CT to detect midline crossing: 50%; accuracy of MRI to detect midline crossing: 100%; accuracy of CT to detect anterior extension: 92%; accuracy of MRI to detect anterior extension: 100%; accuracy of CT to detect tonsillar fossa invasion: 83%; accuracy of MRI to detect tonsillar fossa invasion: 100%; accuracy of CT to detect oro pharyngeal spread: 83%; accuracy of MRI to detect oro pharyngeal spread: 100%; accuracy of CT to detect bone involvement: 20%; accuracy of MRI to detect bone involvement: 100%. MRI proved to be a better investigation than CT, in terms of evaluation of depth of invasion, presence of bony involvement, extension to opposite side, anterior half of tongue, tonsillar fossa, floor of mouth or oropharynx.
Systematic reviews of diagnostic test accuracy
DEFF Research Database (Denmark)
Leeflang, Mariska M G; Deeks, Jonathan J; Gatsonis, Constantine
2008-01-01
More and more systematic reviews of diagnostic test accuracy studies are being published, but they can be methodologically challenging. In this paper, the authors present some of the recent developments in the methodology for conducting systematic reviews of diagnostic test accuracy studies....... Restrictive electronic search filters are discouraged, as is the use of summary quality scores. Methods for meta-analysis should take into account the paired nature of the estimates and their dependence on threshold. Authors of these reviews are advised to use the hierarchical summary receiver...
Systematic Calibration for Ultra-High Accuracy Inertial Measurement Units
Directory of Open Access Journals (Sweden)
Qingzhong Cai
2016-06-01
Full Text Available An inertial navigation system (INS has been widely used in challenging GPS environments. With the rapid development of modern physics, an atomic gyroscope will come into use in the near future with a predicted accuracy of 5 × 10−6°/h or better. However, existing calibration methods and devices can not satisfy the accuracy requirements of future ultra-high accuracy inertial sensors. In this paper, an improved calibration model is established by introducing gyro g-sensitivity errors, accelerometer cross-coupling errors and lever arm errors. A systematic calibration method is proposed based on a 51-state Kalman filter and smoother. Simulation results show that the proposed calibration method can realize the estimation of all the parameters using a common dual-axis turntable. Laboratory and sailing tests prove that the position accuracy in a five-day inertial navigation can be improved about 8% by the proposed calibration method. The accuracy can be improved at least 20% when the position accuracy of the atomic gyro INS can reach a level of 0.1 nautical miles/5 d. Compared with the existing calibration methods, the proposed method, with more error sources and high order small error parameters calibrated for ultra-high accuracy inertial measurement units (IMUs using common turntables, has a great application potential in future atomic gyro INSs.
Haptic perception accuracy depending on self-produced movement.
Park, Chulwook; Kim, Seonjin
2014-01-01
This study measured whether self-produced movement influences haptic perception ability (experiment 1) as well as the factors associated with levels of influence (experiment 2) in racket sports. For experiment 1, the haptic perception accuracy levels of five male table tennis experts and five male novices were examined under two different conditions (no movement vs. movement). For experiment 2, the haptic afferent subsystems of five male table tennis experts and five male novices were investigated in only the self-produced movement-coupled condition. Inferential statistics (ANOVA, t-test) and custom-made devices (shock & vibration sensor, Qualisys Track Manager) of the data were used to determine the haptic perception accuracy (experiment 1, experiment 2) and its association with expertise. The results of this research show that expert-level players acquire higher accuracy with less variability (racket vibration and angle) than novice-level players, especially in their self-produced movement coupled performances. The important finding from this result is that, in terms of accuracy, the skill-associated differences were enlarged during self-produced movement. To explain the origin of this difference between experts and novices, the functional variability of haptic afferent subsystems can serve as a reference. These two factors (self-produced accuracy and the variability of haptic features) as investigated in this study would be useful criteria for educators in racket sports and suggest a broader hypothesis for further research into the effects of the haptic accuracy related to variability.
Accuracy of references and quotations in veterinary journals.
Hinchcliff, K W; Bruce, N J; Powers, J D; Kipp, M L
1993-02-01
The accuracy of references and quotations used to substantiate statements of fact in articles published in 6 frequently cited veterinary journals was examined. Three hundred references were randomly selected, and the accuracy of each citation was examined. A subset of 100 references was examined for quotational accuracy; ie, the accuracy with which authors represented the work or assertions of the author being cited. Of the 300 references selected, 295 were located, and 125 major errors were found in 88 (29.8%) of them. Sixty-seven (53.6%) major errors were found involving authors, 12 (9.6%) involved the article title, 14 (11.2%) involved the book or journal title, and 32 (25.6%) involved the volume number, date, or page numbers. Sixty-eight minor errors were detected. The accuracy of 111 quotations from 95 citations in 65 articles was examined. Nine quotations were technical and not classified, 86 (84.3%) were classified as correct, 2 (1.9%) contained minor misquotations, and 14 (13.7%) contained major misquotations. We concluded that misquotations and errors in citations occur frequently in veterinary journals, but at a rate similar to that reported for other biomedical journals.
Theory and Circuit Model for Lossy Coaxial Transmission Line
Energy Technology Data Exchange (ETDEWEB)
Genoni, T. C.; Anderson, C. N.; Clark, R. E.; Gansz-Torres, J.; Rose, D. V.; Welch, Dale Robert
2017-04-01
The theory of signal propagation in lossy coaxial transmission lines is revisited and new approximate analytic formulas for the line impedance and attenuation are derived. The accuracy of these formulas from DC to 100 GHz is demonstrated by comparison to numerical solutions of the exact field equations. Based on this analysis, a new circuit model is described which accurately reproduces the line response over the entire frequency range. Circuit model calculations are in excellent agreement with the numerical and analytic results, and with finite-difference-time-domain simulations which resolve the skindepths of the conducting walls.
Directory of Open Access Journals (Sweden)
Piotr Francuz
2014-07-01
Full Text Available Background The purpose of this study was to verify hypotheses concerning the effect of three-dimensional imaging and the canonicity of objects presented in the original position on the reaction time (RT and the accuracy (A of mental rotation task (MRT execution. The classical paradigm of MRT, developed by Shepard and Metzler (1971, was used in the experiment. Participants and procedure One hundred fifty-eight undergraduate students (88 female and 70 male, aged 18-30 years, participated in the experiment. All participants had normal vision or corrected vision, and reported no stereo blindness. The sequential version of the MRT was used in the experiment. Participants answered whether the object observed in the second position was only rotated or both rotated and mirror-reversed, in comparison to its original position. The answer (accuracy and its latency (RT were recorded. Results As predicted by the mental rotation model, both the “U”-shaped A-MRT distribution and the inverted “U”-shaped RT-MRT distribution were found, due to the angular disparity. For the RT-MRT, this effect was more pronounced when the objects were displayed stereoscopically than in a plane, and when the objects were presented in the original position from the canonical orientation rather than an unusual point of view. On the other hand, in the case of the A-MRT, an effect of the orientation of objects presented in the original position on strengthening the relationship between accuracy and angular disparity was found. Conclusions The results indicated that the interactions between the presentation of the objects in the mental rotation task (stereoscopically vs. in a plane and the orientation of the object in its original position (canonically vs. unusual are more complicated than would appear from predictions of classical theories of mental rotation. The results of this study are discussed in relation to the theories of recognition and categorization.
Assessment Of Accuracies Of Remote-Sensing Maps
Card, Don H.; Strong, Laurence L.
1992-01-01
Report describes study of accuracies of classifications of picture elements in map derived by digital processing of Landsat-multispectral-scanner imagery of coastal plain of Arctic National Wildlife Refuge. Accuracies of portions of map analyzed with help of statistical sampling procedure called "stratified plurality sampling", in which all picture elements in given cluster classified in stratum to which plurality of them belong.
Ziani, Ahmed
2015-09-03
We report a combined experimental and theoretical study on the optoelectronic properties of α-SnWO4 for UV-Vis excitation. The experimentally measured values for thin films were systematically compared with high-accuracy density functional theory and density functional perturbation theory using the HSE06 functional. The α-SnWO4 material shows an indirect bandgap of 1.52 eV with high absorption coefficient in the visible-light range (>2 × 105 cm−1). The results show relatively high dielectric constant (>30) and weak diffusion properties (large effective masses) of excited carriers.
International Nuclear Information System (INIS)
Pop-Jordanov, J.; Bosevski, T.; Kocic, A.; Altiparmakov, D.
1980-01-01
A Space-Point Energy-Group integral transport theory method (SPEG) is developed and applied to the local and global calculations of the Yugoslav RA reactor. Compared to other integral transport theory methods, the SPEG distinguishes by (1) the arbitrary order of the polynomial, (2) the effective determination of integral parameters through point flux values, (3) the use of neutron balance condition. as a posterior measure of the accuracy of the calculation and (4) the elimination of the subdivisions- into zones, in realistic cases. In addition, different direct (collision probability) and indirect (Monte Carlo) approaches to integral transport theory have been investigated and Some effective acceleration procedures introduced. The study was performed on three test problems in plane and cylindrical geometry, as well as on the nine-region cell of the RA reactor. In particular, the limitations of the integral transport theory including its non-applicability to optically large material regions and to global reactor calculations were examined. The proposed strictly multipoint approach, avoiding the subdivision into zones and groups, seems to provide a good starting point to overcome these limitations of the integral transport theory. (author)
Directory of Open Access Journals (Sweden)
Hamid M. Sedighi
Full Text Available This paper investigates the dynamic pull-in instability of vibrating micro-beams undergoing large deflection under electrosatically actuation. The governing equation of motion is derived based on the modified couple stress theory. Homotopy Perturbation Method is employed to produce the high accuracy approximate solution as well as the second-order frequency- amplitude relationship. The nonlinear governing equation of micro beam vibrations predeformed by an electric field includes both even and odd nonlinearities. The influences of basic non-dimensional parameters on the pull-in instability as well as the natural frequency are studied. It is demonstrated that two terms in series expansions are sufficient to produce high accuracy solution of the micro-structure. The accuracy of proposed asymptotic approach is validated via numerical results. The phase portrait of the system exhibits periodic and homoclinic orbits.
Directory of Open Access Journals (Sweden)
Luis Henrique Guilherme
2014-03-01
Full Text Available O aço inoxidável AISI 444 tornou-se uma opção para substituir a liga AISI 316L devido ao seu menor custo e satisfatória resistência à corrosão. Entretanto, o uso da liga AISI 444 no feixe tubular de trocadores de calor acarreta na soldagem de uma junta dissimilar. O presente estudo teve por objetivo avaliar a resistência à corrosão da junta tubo-espelho soldada pelo processo TIG composta pelas ligas AISI 316L e AISI 444. A manufatura das amostras consistiu em replicar o projeto da junta tubo-espelho de trocadores de calor. Realizou-se em juntas soldadas ensaios de sensitização, perda de massa por imersão desde a temperatura ambiente até 90 ºC, e ensaios eletroquímicos de polarização potenciodinâmica nos eletrólitos 0,5 mol/L de HCl e 0,5 mol/L de H2SO4. Os resultados mostraram que a junta dissimilar sofreu corrosão galvânica com maior degradação na zona afetada pelo calor (ZAC do tubo AISI 444. Porém, os mecanismos de corrosão localizada (pite e intergranular demonstraram ser mais ativos para a liga AISI 316L. Conclui-se que a junta dissimilar apresentou melhor resistência à corrosão do que a junta soldada composta unicamente pela liga AISI 316L em temperaturas de até 70 ºC, conforme as condições observadas neste trabalho.
A Prospective Study Comparing Ligasure and Open Hemorrhoidectomy
Directory of Open Access Journals (Sweden)
Rahimi M
2011-11-01
Full Text Available Background: Hemorrhoid is among the most common anorectal diseases and patients with high-grade disease conditions need surgical treatment. Many surgical procedures are available to treat the disease. The aim of this study was to compare the operative time and outcomes, (post-operative pain and complications of LigaSure hemorrhoidectomy with those of the open conventional method.Methods : This randomized single-blind clinical trial included 57 patients (28 in LigaSure and 29 in the open group. The primary variable was the operative time for the excision of a single hemorrhoidal packet. The other variables were post-operative pain measured by morphine doses administered to control pain, scores of visual analogue scale (VAS used to measure pain severity, pain during home stay measured by doses of oral ibuprofen and the mean daily VAS scores, early complications including bleeding and urinary retention, longer-term complications and time to return to work.Results : The demographic data were comparatively the same between the two groups. The average time to excise a single packet of hemorrhoid was significantly shorter in the LigaSure group (8.91 min vs. 17.35 min, P<0.001. Post-operative pain measurements (morphine doses and VAS scores were lower in the LigaSure group, but the differences were not statistically significant (P=0.055 and 0.077, respectively. Complications of the two procedures were also comparable. Neither of the groups returned to work in a shorter time.Conclusion: LigaSure hemorrhoidectomy seems to be a safe method and it can reduce the operative time significantly. It may also have a modest effect on post-operative pain.
Fast and accurate covalent bond predictions using perturbation theory in chemical space
Chang, Kuang-Yu; von Lilienfeld, Anatole
I will discuss the predictive accuracy of perturbation theory based estimates of changes in covalent bonding due to linear alchemical interpolations among systems of different chemical composition. We have investigated single, double, and triple bonds occurring in small sets of iso-valence-electronic molecular species with elements drawn from second to fourth rows in the p-block of the periodic table. Numerical evidence suggests that first order estimates of covalent bonding potentials can achieve chemical accuracy (within 1 kcal/mol) if the alchemical interpolation is vertical (fixed geometry) among chemical elements from third and fourth row of the periodic table. When applied to nonbonded systems of molecular dimers or solids such as III-V semiconductors, alanates, alkali halides, and transition metals, similar observations hold, enabling rapid predictions of van der Waals energies, defect energies, band-structures, crystal structures, and lattice constants.
Cosmic string solution in a Born-Infeld type theory of gravity
International Nuclear Information System (INIS)
Rocha, W.J. da; Guimaraes, M.E.X.
2009-01-01
Full text. Advances in the formal structure of string theory point to the emergence, and necessity, of a scalar-tensorial theory of gravity. It seems that, at least at high energy scales, the Einstein's theory is not enough to explain the gravitational phenomena. In other words, the existence of a scalar (gravitational) field acting as a mediator of the gravitational interaction together with the usual purely rank-2 tensorial field is, indeed, a natural prediction of unification models as supergravity, superstrings and M-theory. This type of modified gravitation was first introduced in a different context in the 60's in order to incorporate the Mach's principle into relativity, but nowadays it acquired different sense in cosmology and gravity theories. Although such unification theories are the most acceptable, they all exist in higher dimensional spaces. The compactification from these higher dimensions to the 4-dimensional physics is not unique and there exist many effective theories of gravity which come from the unification process. Each of them must, of course, satisfy some predictions. Here, in this paper, we will deal with one of them. The so-called NDL theory. One important assumption in General Relativity is that all field interact in the same way with gravity. This is the so called Strong Equivalence Principle (SEP). It is well known, with good accuracy, that this is true when we concern with matter to matter interaction, i.e, the Weak Equivalence Principle(WEP) is tested. But, until now, there is no direct observational confirmation of this affirmation to the gravity to gravity interaction. In an extension of the field theoretical description of General Relativity constructed by is used to propose an alternative field theory of gravity. In this theory gravitons propagate in a different spacetime. The velocity of propagation of the gravitational waves in this theory does not coincide with the General Relativity predictions. (author)
Generalized diffusion theory for calculating the neutron transport scalar flux
International Nuclear Information System (INIS)
Alcouffe, R.E.
1975-01-01
A generalization of the neutron diffusion equation is introduced, the solution of which is an accurate approximation to the transport scalar flux. In this generalization the auxiliary transport calculations of the system of interest are utilized to compute an accurate, pointwise diffusion coefficient. A procedure is specified to generate and improve this auxiliary information in a systematic way, leading to improvement in the calculated diffusion scalar flux. This improvement is shown to be contingent upon satisfying the condition of positive calculated-diffusion coefficients, and an algorithm that ensures this positivity is presented. The generalized diffusion theory is also shown to be compatible with conventional diffusion theory in the sense that the same methods and codes can be used to calculate a solution for both. The accuracy of the method compared to reference S/sub N/ transport calculations is demonstrated for a wide variety of examples. (U.S.)
Strand Tension Control in Anchor Span for Suspension Bridge Using Dynamic Balance Theory
Directory of Open Access Journals (Sweden)
Da Wang
Full Text Available Abstract Strand tension control is essential in suspension bridge safety. However, few quantitative studies have examined the bending rigidity and boundary condition behavior of strands in the anchor span of suspension bridges because of their special structure and complex configuration. In this paper, a new calculation method for strand tension is explored by using dynamic balance theory to determine the effect of bending rigidity and boundary conditions. The accuracy and effectiveness of the proposed method are tested and confirmed with verification examples and application on Nanxi Yangtze Suspension Bridge in China. The results indicated that only low-order frequency calculation could be used to calculate the strand tension without considering the effect of bending rigidity to ensure control accuracy. The influence of bending rigidity on the control precision is related to the tension and the length of the strands, which is significantly determined by the specific value between the stress rigidity and the bending rigidity. The uncertain boundary conditions of the anchor span cable, which are fixed between consolidated and hinged, also have a major effect on the control accuracy. To improve the accuracy of strand tension control, the least squares method is proposed during the tension construction control of the anchor span. This approach can significantly improve the accuracy of the tension control of the main cable strand. Some recommendations for future bridge analysis are provided based on the results of this study.
Laser measuring scanners and their accuracy limits
Jablonski, Ryszard
1993-09-01
Scanning methods have gained the greater importance for some years now due to a short measuring time and wide range of application in flexible manufacturing processes. This paper is a summing up of the autho?s creative scientific work in the field of measuring scanners. The research conducted allowed to elaborate the optimal configurations of measuring systems based on the scanning method. An important part of the work was the analysis of a measuring scanner - as a transducer of an angle rotation into the linear displacement which resulted in obtaining its much higher accuracy and finally in working out a measuring scanner eliminating the use of an additional reference standard. The completion of the work is an attempt to determine an attainable accuracy limit of scanning measurement of both length and angle. Using a high stability deflector and a corrected scanning lens one can obtain the angle determination over 30 (or 2 mm) to an accuracy 0 (or 0 tm) when the measuring rate is 1000 Hz or the range d60 (4 mm) with accuracy 0 " (0 jim) and measurement frequency 6 Hz.
High accuracy autonomous navigation using the global positioning system (GPS)
Truong, Son H.; Hart, Roger C.; Shoan, Wendy C.; Wood, Terri; Long, Anne C.; Oza, Dipak H.; Lee, Taesul
1997-01-01
The application of global positioning system (GPS) technology to the improvement of the accuracy and economy of spacecraft navigation, is reported. High-accuracy autonomous navigation algorithms are currently being qualified in conjunction with the GPS attitude determination flyer (GADFLY) experiment for the small satellite technology initiative Lewis spacecraft. Preflight performance assessments indicated that these algorithms are able to provide a real time total position accuracy of better than 10 m and a velocity accuracy of better than 0.01 m/s, with selective availability at typical levels. It is expected that the position accuracy will be increased to 2 m if corrections are provided by the GPS wide area augmentation system.
Quantum Monte Carlo studies in Hamiltonian lattice gauge theory
International Nuclear Information System (INIS)
Hamer, C.J.; Samaras, M.; Bursill, R.J.
2000-01-01
Full text: The application of Monte Carlo methods to the 'Hamiltonian' formulation of lattice gauge theory has been somewhat neglected, and lags at least ten years behind the classical Monte Carlo simulations of Euclidean lattice gauge theory. We have applied a Green's Function Monte Carlo algorithm to lattice Yang-Mills theories in the Hamiltonian formulation, combined with a 'forward-walking' technique to estimate expectation values and correlation functions. In this approach, one represents the wave function in configuration space by a discrete ensemble of random walkers, and application of the time development operator is simulated by a diffusion and branching process. The approach has been used to estimate the ground-state energy and Wilson loop values in the U(1) theory in (2+1)D, and the SU(3) Yang-Mills theory in (3+1)D. The finite-size scaling behaviour has been explored, and agrees with the predictions of effective Lagrangian theory, and weak-coupling expansions. Crude estimates of the string tension are derived, which agree with previous results at intermediate couplings; but more accurate results for larger loops will be required to establish scaling behaviour at weak couplings. A drawback to this method is that it is necessary to introduce a 'trial' or 'guiding wave function' to guide the walkers towards the most probable regions of configuration space, in order to achieve convergence and accuracy. The 'forward-walking' estimates should be independent of this guidance, but in fact for the SU(3) case they turn out to be sensitive to the choice of trial wave function. It would be preferable to use some sort of Metropolis algorithm instead to produce a correct distribution of walkers: this may point in the direction of a Path Integral Monte Carlo approach
Scalar mass relations and flavor violations in supersymmetric theories
International Nuclear Information System (INIS)
Cheng, Hsin-Chia; California Univ., Berkeley, CA
1996-01-01
Supersymmetry provides the most promising solution to the gauge hierarchy problem. For supersymmetry to stablize the hierarchy, it must be broken at the weak scale. The combination of weak scale supersymmetry and grand unification leads to a successful prediction of the weak mixing angle to within 1% accuracy. If supersymmetry is a symmetry of nature, the mass spectrum and the flavor mixing pattern of the scalar superpartners of all the quarks and leptons will provide important information about a more fundamental theory at higher energies. We studied the scalar mass relations which follow from the assumption that at high energies there is a grand unified theory which leads to a significant prediction of the weak mixing angle; these will serve as important tests of grand unified theories. Two intragenerational mass relations for each of the light generations are derived. A third relation is also found which relates the Higgs masses and the masses of all three generation scalars. In a realistic supersymmetric grand unified theory, nontrivial flavor mixings are expected to exist at all gaugino vertices. This could lead to important contributions to the neutron electric dipole moment, the decay mode p → K 0 μ + , weak scale radiative corrections to the up-type quark masses, and lepton flavor violating signals such as μ → eγ. These also provide important probes of physics at high energy scales. Supersymmetric theories involving a spontaneously broken flavor symmetry can provide a solution to the supersymmetric flavor-changing problem and an understanding of the fermion masses and mixings. We studied the possibilities and the general conditions under which some fermion masses and mixings can be obtained radiatively. We also constructed theories of flavor in which the first generation fermion masses arise from radiative corrections while flavor-changing constraints are satisfied. 69 refs., 19 figs., 9 tabs