Kelly, Patrick J; Stocking, Ruey; Gao, Dongya; Phillips, Nikol; Xu, Chuanling; Kaltenboeck, Bernhard; Wang, Chengming
2011-07-04
Although antibodies to the feline immunodeficiency virus (FIV) have been detected by SNAP assay in cats from St. Kitts, there have been no molecular studies to further confirm the infection and determine the FIV subtypes present. Total nucleic acids were extracted from EDTA whole blood specimens from 35 cats, followed by quantitative fluorescence resonance energy transfer (FRET) PCR under a six-channel LightCycler 2.0 Instrument with Software version 4.1. Four of 11 stray cats (36 %) but none of 24 owned cats were FIV positive by real-time PCR. High-resolution melting curve analysis indicated that all four positive cats were infected with FIV subtype-B. This is the first molecular characterization of FIV subtypes on St. Kitts and the results confirm the high prevalence of FIV infection in stray cats on the island.
The learning curve: implications of a quantitative analysis.
Gallistel, Charles R; Fairhurst, Stephen; Balsam, Peter
2004-09-07
The negatively accelerated, gradually increasing learning curve is an artifact of group averaging in several commonly used basic learning paradigms (pigeon autoshaping, delay- and trace-eye-blink conditioning in the rabbit and rat, autoshaped hopper entry in the rat, plus maze performance in the rat, and water maze performance in the mouse). The learning curves for individual subjects show an abrupt, often step-like increase from the untrained level of responding to the level seen in the well trained subject. The rise is at least as abrupt as that commonly seen in psychometric functions in stimulus detection experiments. It may indicate that the appearance of conditioned behavior is mediated by an evidence-based decision process, as in stimulus detection experiments. If the appearance of conditioned behavior is taken instead to reflect the increase in an underlying associative strength, then a negligible portion of the function relating associative strength to amount of experience is behaviorally visible. Consequently, rate of learning cannot be estimated from the group-average curve; the best measure is latency to the onset of responding, determined for each subject individually.
Mathematics of quantitative kinetic PCR and the application of standard curves.
Rutledge, R G; Côté, C
2003-08-15
Fluorescent monitoring of DNA amplification is the basis of real-time PCR, from which target DNA concentration can be determined from the fractional cycle at which a threshold amount of amplicon DNA is produced. Absolute quantification can be achieved using a standard curve constructed by amplifying known amounts of target DNA. In this study, the mathematics of quantitative PCR are examined in detail, from which several fundamental aspects of the threshold method and the application of standard curves are illustrated. The construction of five replicate standard curves for two pairs of nested primers was used to examine the reproducibility and degree of quantitative variation using SYBER Green I fluorescence. Based upon this analysis the application of a single, well- constructed standard curve could provide an estimated precision of +/-6-21%, depending on the number of cycles required to reach threshold. A simplified method for absolute quantification is also proposed, in which quantitative scale is determined by DNA mass at threshold.
Energy Technology Data Exchange (ETDEWEB)
Wang, Qi, E-mail: wq20@hotmail.com; Shi, Gaofeng, E-mail: gaofengs62@sina.com; Qi, Xiaohui, E-mail: qixiaohui1984@163.com; Fan, Xueli, E-mail: 407849960@qq.com; Wang, Lijia, E-mail: 893197597@qq.com
2014-10-15
Highlights: • We establish a feasible method using the virtual spectral curves (VSC) to differentiate focal liver lesions using DECT. • Our study shows the slope of the VSC can be used to differentiate between hemangioma, HCC, metastasis and cyst. • Importantly, the diagnostic specificities associated with using the slope to diagnose both hemangioma and cysts were 100%. - Abstract: Objective: To assess the usefulness of the spectral curve slope of dual-energy CT (DECT) for differentiating between hepatocellular carcinoma (HCC), hepatic metastasis, hemangioma (HH) and cysts. Methods: In total, 121 patients were imaged in the portal venous phase using dual-energy mode. Of these patients, 23 patients had HH, 28 patients had HCC, 40 patients had metastases and 30 patients had simple cysts. The spectral curves of the hepatic lesions were derived from the 40–190 keV levels of virtual monochromatic spectral imaging. The spectral curve slopes were calculated from 40 to 110 keV. The slopes were compared using the Kruskal–Wallis test. Receiver operating characteristic curves (ROC) were used to determine the optimal cut-off value of the slope of the spectral curve to differentiate between the lesions. Results: The spectral curves of the four lesion types had different baseline levels. The HH baseline level was the highest followed by HCC, metastases and cysts. The slopes of the spectral curves of HH, HCC, metastases and cysts were 3.81 ± 1.19, 1.49 ± 0.57, 1.06 ± 0.76 and 0.13 ± 0.17, respectively. These values were significantly different (P < 0.008). Based on ROC analysis, the respective diagnostic sensitivity and specificity were 87% and 100% for hemangioma (cut-off value ≥ 2.988), 82.1% and 65.9% for HCC (cut-off value 1.167–2.998), 65.9% and 59% for metastasis (cut-off value 0.133–1.167) and 44.4% and 100% for cysts (cut-off value ≤ 0.133). Conclusion: Quantitative analysis of the DECT spectral curve in the portal venous phase can be used to
Diagnostic accuracy of quantitative 99mTc-MIBI scintimammography according to ROC curve analysis
International Nuclear Information System (INIS)
Kim, J. H.; Lee, H. K.; Seo, J. W.; Cho, N. S.; Cha, K. H.; Lee, T. H.
1998-01-01
99mTc-sestamibi scintimammography (SMM) has been shown to be a useful diagnostic test in the detection of breast cancer and the receiver operating characteristic (ROC) curve analysis provides detailed information of a diagnostic test. The purpose of this study was to evaluate the feasibility and efficacy of quantitative indices of SMM in the detection of malignant breast lesions according to ROC analysis. Prone anterior, lateral planar and supine SPECT imagings were performed on 75 female patients (mean age=43.4 yr) with breast mass (size≥0.8cm) after intravenous injection of 20-30 mCi 99mTc-sestamibi. 45 Malignant (Invasive ductal ca(36), Inv lobular ca(5), Inv duc + lob (1), Inv tubular ca (3)) and 30 benign (fibroadenoma (13), fib cyst(12), Fat necrosis(3), papilloma(1), paraffinoma (1)) lesions were histologically proven. Data were analyzed by creating three regions of interest (ROIs) over designated areas: lesion, normal breast and right chest wall. Lesion to normal (L/NL) and lesion to chest wall (L/CW) ratios were calculated for each patient both on the planar and SPECT. The area under the ROC curve (AUC) was calculated and compared among four semiquantitative indices and an average scintimammographic index (SMM(mean)) from arithmatic mean. ROC curve analysis revealed planar L/N, SPECT L/N and L/CW ratios provide comparable better diagnostic accuracies for detection of breast cancer than planar L/CW ratio (p<0.05), respectively. For quantitative SMM of 75 lesions, malignancy rate was 60%, and Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value and Accuracy were 0.78, 0.77, 0.84, 0.72 and 0.77, respectively. Quantitative SMM is an useful objective method for differentiating malignant from benign breast lesions
Diagnostic accuracy of quantitative 99mTc-MIBI scintimammography according to ROC curve analysis
Energy Technology Data Exchange (ETDEWEB)
Kim, J. H.; Lee, H. K.; Seo, J. W.; Cho, N. S.; Cha, K. H.; Lee, T. H. [Gachon Medical College, Gil Medical Center, Inchon (Korea, Republic of)
1998-07-01
99mTc-sestamibi scintimammography (SMM) has been shown to be a useful diagnostic test in the detection of breast cancer and the receiver operating characteristic (ROC) curve analysis provides detailed information of a diagnostic test. The purpose of this study was to evaluate the feasibility and efficacy of quantitative indices of SMM in the detection of malignant breast lesions according to ROC analysis. Prone anterior, lateral planar and supine SPECT imagings were performed on 75 female patients (mean age=43.4 yr) with breast mass (size{>=}0.8cm) after intravenous injection of 20-30 mCi 99mTc-sestamibi. 45 Malignant (Invasive ductal ca(36), Inv lobular ca(5), Inv duc + lob (1), Inv tubular ca (3)) and 30 benign (fibroadenoma (13), fib cyst(12), Fat necrosis(3), papilloma(1), paraffinoma (1)) lesions were histologically proven. Data were analyzed by creating three regions of interest (ROIs) over designated areas: lesion, normal breast and right chest wall. Lesion to normal (L/NL) and lesion to chest wall (L/CW) ratios were calculated for each patient both on the planar and SPECT. The area under the ROC curve (AUC) was calculated and compared among four semiquantitative indices and an average scintimammographic index (SMM(mean)) from arithmatic mean. ROC curve analysis revealed planar L/N, SPECT L/N and L/CW ratios provide comparable better diagnostic accuracies for detection of breast cancer than planar L/CW ratio (p<0.05), respectively. For quantitative SMM of 75 lesions, malignancy rate was 60%, and Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value and Accuracy were 0.78, 0.77, 0.84, 0.72 and 0.77, respectively. Quantitative SMM is an useful objective method for differentiating malignant from benign breast lesions.
Accuracy in the estimation of quantitative minimal area from the diversity/area curve.
Vives, Sergi; Salicrú, Miquel
2005-05-01
The problem of representativity is fundamental in ecological studies. A qualitative minimal area that gives a good representation of species pool [C.M. Bouderesque, Methodes d'etude qualitative et quantitative du benthos (en particulier du phytobenthos), Tethys 3(1) (1971) 79] can be discerned from a quantitative minimal area which reflects the structural complexity of community [F.X. Niell, Sobre la biologia de Ascophyllum nosodum (L.) Le Jolis en Galicia, Invest. Pesq. 43 (1979) 501]. This suggests that the populational diversity can be considered as the value of the horizontal asymptote corresponding to the curve sample diversity/biomass [F.X. Niell, Les applications de l'index de Shannon a l'etude de la vegetation interdidale, Soc. Phycol. Fr. Bull. 19 (1974) 238]. In this study we develop a expression to determine minimal areas and use it to obtain certain information about the community structure based on diversity/area curve graphs. This expression is based on the functional relationship between the expected value of the diversity and the sample size used to estimate it. In order to establish the quality of the estimation process, we obtained the confidence intervals as a particularization of the functional (h-phi)-entropies proposed in [M. Salicru, M.L. Menendez, D. Morales, L. Pardo, Asymptotic distribution of (h,phi)-entropies, Commun. Stat. (Theory Methods) 22 (7) (1993) 2015]. As an example used to demonstrate the possibilities of this method, and only for illustrative purposes, data about a study on the rocky intertidal seawed populations in the Ria of Vigo (N.W. Spain) are analyzed [F.X. Niell, Estudios sobre la estructura, dinamica y produccion del Fitobentos intermareal (Facies rocosa) de la Ria de Vigo. Ph.D. Mem. University of Barcelona, Barcelona, 1979].
Directory of Open Access Journals (Sweden)
John Stephen Yap
2007-06-01
Full Text Available Whether and how thermal reaction norm is under genetic control is fundamental to understand the mechanistic basis of adaptation to novel thermal environments. However, the genetic study of thermal reaction norm is difficult because it is often expressed as a continuous function or curve. Here we derive a statistical model for dissecting thermal performance curves into individual quantitative trait loci (QTL with the aid of a genetic linkage map. The model is constructed within the maximum likelihood context and implemented with the EM algorithm. It integrates the biological principle of responses to temperature into a framework for genetic mapping through rigorous mathematical functions established to describe the pattern and shape of thermal reaction norms. The biological advantages of the model lie in the decomposition of the genetic causes for thermal reaction norm into its biologically interpretable modes, such as hotter-colder, faster-slower and generalist-specialist, as well as the formulation of a series of hypotheses at the interface between genetic actions/interactions and temperature-dependent sensitivity. The model is also meritorious in statistics because the precision of parameter estimation and power of QTLdetection can be increased by modeling the mean-covariance structure with a small set of parameters. The results from simulation studies suggest that the model displays favorable statistical properties and can be robust in practical genetic applications. The model provides a conceptual platform for testing many ecologically relevant hypotheses regarding organismic adaptation within the Eco-Devo paradigm.
Energy Technology Data Exchange (ETDEWEB)
Michoux, N.; Montet, X.; Pechere, A.; Ivancevic, M.K.; Martin, P.-Y.; Keller, A.; Didier, D.; Terrier, F.; Vallee, J.-P
2005-04-01
The aim of this study was to refine the description of the renal function based on MR images and through transit-time curve analysis on a normal population and on a population with renal failure, using the quantitative model of the up-slope. Thirty patients referred for a kidney MR exam were divided in a first population with well-functioning kidneys and in a second population with renal failure from ischaemic kidney disease. The perfusion sequence consisted of an intravenous injection of Gd-DTPA and of a fast GRE sequence T1-TFE with 90 deg. magnetisation preparation (Intera 1.5 T MR System, Philips Medical System). To convert the signal intensity into 1/T1, which is proportional to the contrast media concentration, a flow-corrected calibration procedure was used. Following segmentation of regions of interest in the cortex and medulla of the kidney and in the abdominal aorta, outflow curves were obtained and filtered to remove the high frequency fluctuations. The model of the up-slope method was then applied. Significant reduction of the cortical perfusion (Q{sub c}=0.057{+-}0.030 ml/(s 100 g) to Q{sub c}=0.030{+-}0.017 ml/(s 100 g), P<0.013), of the medullary perfusion (Q{sub m}=0.023{+-}0.018 ml/(s 100 g) to Q{sub m}=0.011{+-}0.006 ml/(s 100 g), P<0.046) and of the accumulation of contrast media in the medulla (Q{sub a}=0.005{+-}0.003 ml/(s 100 g) to Q{sub a}=0.0009{+-}0.0008 ml/(s 100 g), P<0.001) were found in presence of renal failure. High correlations were found between the creatinine level and the accumulation Q{sub a} in the medulla (r{sup 2}=0.72, P<0.05), and between the perfusion ratio Q{sub c}/Q{sub m} and the accumulation Q{sub a} in the medulla (r{sup 2}=0.81, P<0.05). No significant difference was found in times to peak between both populations despite a trend showing T{sub a} the time to the end of the increasing contrast accumulation period in the medulla, arriving later for renal failure. Advances in MR signal calibration with the building of
Quantitative analysis by laser-induced breakdown spectroscopy based on generalized curves of growth
Energy Technology Data Exchange (ETDEWEB)
Aragón, C., E-mail: carlos.aragon@unavarra.es; Aguilera, J.A.
2015-08-01
A method for quantitative elemental analysis by laser-induced breakdown spectroscopy (LIBS) is proposed. The method (Cσ-LIBS) is based on Cσ graphs, generalized curves of growth which allow including several lines of various elements at different concentrations. A so-called homogeneous double (HD) model of the laser-induced plasma is used, defined by an integration over a single-region of the radiative transfer equation, combined with a separated treatment for neutral atoms (z = 0) and singly-charged ions (z = 1) in Cσ graphs and characteristic parameters. The procedure includes a criterion, based on a model limit, for eliminating data which, due to a high line intensity or concentration, are not well described by the HD model. An initial procedure provides a set of parameters (βA){sup z}, (ηNl){sup z}, T{sup z} and N{sub e}{sup z} (z = 0, 1) which characterize the plasma and the LIBS system. After characterization, two different analytical procedures, resulting in relative and absolute concentrations, may be applied. To test the method, fused glass samples prepared from certified slags and pure compounds are analyzed. We determine concentrations of Ca, Mn, Mg, V, Ti, Si and Al relative to Fe in three samples prepared from slags, and absolute concentrations of Fe, Ca and Mn in three samples prepared from Fe{sub 2}O{sub 3}, CaCO{sub 3} and Mn{sub 2}O{sub 3}. The accuracy obtained is 3.2% on the average for relative concentrations and 9.2% for absolute concentrations. - Highlights: • Method for quantitative analysis by LIBS, based on Csigma graphs • Conventional calibration is replaced with characterization of the LIBS system. • All elements are determined from measurement of one or two Csigma graphs. • The method is tested with fused glass disks prepared from slags and pure compounds. • Accurate results for relative (3.2%) and absolute concentrations (9.2%)
Gaschler, Robert; Progscha, Johanna; Smallbone, Kieran; Ram, Nilam; Bilalić, Merim
2014-01-01
Learning curves have been proposed as an adequate description of learning processes, no matter whether the processes manifest within minutes or across years. Different mechanisms underlying skill acquisition can lead to differences in the shape of learning curves. In the current study, we analyze the tournament performance data of 1383 chess players who begin competing at young age and play tournaments for at least 10 years. We analyze the performance development with the goal to test the adequacy of learning curves, and the skill acquisition theories they are based on, for describing and predicting expertise acquisition. On the one hand, we show that the skill acquisition theories implying a negative exponential learning curve do a better job in both describing early performance gains and predicting later trajectories of chess performance than those theories implying a power function learning curve. On the other hand, the learning curves of a large proportion of players show systematic qualitative deviations from the predictions of either type of skill acquisition theory. While skill acquisition theories predict larger performance gains in early years and smaller gains in later years, a substantial number of players begin to show substantial improvements with a delay of several years (and no improvement in the first years), deviations not fully accounted for by quantity of practice. The current work adds to the debate on how learning processes on a small time scale combine to large-scale changes.
DEFF Research Database (Denmark)
Kjems, Ulrik; Hansen, Lars Kai; Anderson, Jon
2002-01-01
Learning curves are presented as an unbiased means for evaluating the performance of models for neuroimaging data analysis. The learning curve measures the predictive performance in terms of the generalization or prediction error as a function of the number of independent examples (e.g., subjects......) used to determine the parameters in the model. Cross-validation resampling is used to obtain unbiased estimates of a generic multivariate Gaussian classifier, for training set sizes from 2 to 16 subjects. We apply the framework to four different activation experiments, in this case \\$\\backslash......\\$[/sup 15/ O]water data sets, although the framework is equally valid for multisubject fMRI studies. We demonstrate how the prediction error can be expressed as the mutual information between the scan and the scan label, measured in units of bits. The mutual information learning curve can be used...
A method of non-destructive quantitative analysis of the ancient ceramics with curved surface
International Nuclear Information System (INIS)
He Wenquan; Xiong Yingfei
2002-01-01
Generally the surface of the sample should be smooth and flat in XRF analysis, but the ancient ceramics and hardly match this condition. Two simple methods are put forward in fundamental method and empirical correction method of XRF analysis, so the analysis of little sample or the sample with curved surface can be easily completed
Janwan, Penchom; Intapan, Pewpan M; Thanchomnang, Tongjit; Lulitanond, Viraphong; Anamnart, Witthaya; Maleewong, Wanchai
2011-12-01
Human opisthorchiasis caused by the liver fluke Opisthorchis viverrini is an endemic disease in Southeast Asian countries including the Lao People's Democratic Republic, Cambodia, Vietnam, and Thailand. Infection with the soil-transmitted roundworm Strongyloides stercoralis is an important problem worldwide. In some areas, both parasitic infections are reported as co-infections. A duplex real-time fluorescence resonance energy transfer (FRET) PCR merged with melting curve analysis was developed for the rapid detection of O. viverrini and S. stercoralis in human fecal samples. Duplex real-time FRET PCR is based on fluorescence melting curve analysis of a hybrid of amplicons generated from two genera of DNA elements: the 162 bp pOV-A6 DNA sequence specific to O. viverrini and the 244 bp 18S rRNA sequence specific to S. stercoralis, and two pairs of specific fluorophore-labeled probes. Both O. viverrini and S. stercoralis can be differentially detected in infected human fecal samples by this process through their different fluorescence channels and melting temperatures. Detection limit of the method was as little as two O. viverrini eggs and four S. stercoralis larvae in 100 mg of fecal sample. The assay could distinguish the DNA of both parasites from the DNA of negative fecal samples and fecal samples with other parasite materials, as well as from the DNA of human leukocytes and other control parasites. The technique showed 100% sensitivity and specificity. The introduced duplex real-time FRET PCR can reduce labor time and reagent costs and is not prone to carry over contamination. The method is important for simultaneous detection especially in areas where both parasites overlap incidence and is useful as the screening tool in the returning travelers and immigrants to industrialized countries where number of samples in the diagnostic units will become increasing.
Bauza, María C; Ibañez, Gabriela A; Tauler, Romà; Olivieri, Alejandro C
2012-10-16
A new equation is derived for estimating the sensitivity when the multivariate curve resolution-alternating least-squares (MCR-ALS) method is applied to second-order multivariate calibration data. The validity of the expression is substantiated by extensive Monte Carlo noise addition simulations. The multivariate selectivity can be derived from the new sensitivity expression. Other important figures of merit, such as limit of detection, limit of quantitation, and concentration uncertainty of MCR-ALS quantitative estimations can be easily estimated from the proposed sensitivity expression and the instrumental noise. An experimental example involving the determination of an analyte in the presence of uncalibrated interfering agents is described in detail, involving second-order time-decaying sensitized lanthanide luminescence excitation spectra. The estimated figures of merit are reasonably correlated with the analytical features of the analyzed experimental system.
Cell survival curves deduced from non-quantitative reactions of skin, intestinal mucosa and lung
International Nuclear Information System (INIS)
Dutreix, J.; Wambersie, A.
1975-01-01
The shape of the cell survival curve for the cell population relevant to some biological effects has been derived from the comparison of the total doses which result in the same biological effect for two irradiations delivered with N and 2N fractions in the same overall time. They show an initial slope which is interpreted as related to directly lethal, i.e. 'one-hit' or 'irreparable' events. The ratio of the initial slope and the slope at a dose D gives the contribution of the cell killing by directly lethal events relative to cell killing by accumulation of sublethal events. The bioligical effects which have been studied are: (i) dry desquamation of the skin of C 3 H mice and patients; (ii) intestinal death of BALB/c mice; and (iii) lung death of C 3 H mice. The shape of the cell survival curve has been found to be similar for skin desquamation and for intestinal death with a large contribution of lethal events, at single doses of 1000 rad. For lung death the initial tangent has a smaller slope and the shoulder is broader; this is interpreted as a relatively smaller contribution of lethal events with respect to accumulation of sublethal events. (author)
Rodríguez-Reyes, Juan Carlos F.; Teplyakov, Andrew V.; Brown, Steven D.
2010-10-01
The substantial amount of information carried in temperature-programmed desorption (TPD) experiments is often difficult to mine due to the occurrence of competing reaction pathways that produce compounds with similar mass spectrometric features. Multivariate curve resolution (MCR) is introduced as a tool capable of overcoming this problem by mathematically detecting spectral variations and correlations between several m/z traces, which is later translated into the extraction of the cracking pattern and the desorption profile for each desorbate. Different from the elegant (though complex) methods currently available to analyze TPD data, MCR analysis is applicable even when no information regarding the specific surface reaction/desorption process or the nature of the desorbing species is available. However, when available, any information can be used as constraints that guide the outcome, increasing the accuracy of the resolution. This approach is especially valuable when the compounds desorbing are different from what would be expected based on a chemical intuition, when the cracking pattern of the model test compound is difficult or impossible to obtain (because it could be unstable or very rare), and when knowing major components desorbing from the surface could in more traditional methods actually bias the quantification of minor components. The enhanced level of understanding of thermal processes achieved through MCR analysis is demonstrated by analyzing three phenomena: i) the cryogenic desorption of vinyltrimethylsilane from silicon, an introductory system where the known multilayer and monolayer components are resolved; ii) acrolein hydrogenation on a bimetallic Pt-Ni-Pt catalyst, where a rapid identification of hydrogenated products as well as other desorbing species is achieved, and iii) the thermal reaction of Ti[N(CH 3) 2] 4 on Si(100), where the products of surface decomposition are identified and an estimation of the surface composition after the
de Godoy, Luiz Antonio Fonseca; Hantao, Leandro Wang; Pedroso, Marcio Pozzobon; Poppi, Ronei Jesus; Augusto, Fabio
2011-08-05
The use of multivariate curve resolution (MCR) to build multivariate quantitative models using data obtained from comprehensive two-dimensional gas chromatography with flame ionization detection (GC×GC-FID) is presented and evaluated. The MCR algorithm presents some important features, such as second order advantage and the recovery of the instrumental response for each pure component after optimization by an alternating least squares (ALS) procedure. A model to quantify the essential oil of rosemary was built using a calibration set containing only known concentrations of the essential oil and cereal alcohol as solvent. A calibration curve correlating the concentration of the essential oil of rosemary and the instrumental response obtained from the MCR-ALS algorithm was obtained, and this calibration model was applied to predict the concentration of the oil in complex samples (mixtures of the essential oil, pineapple essence and commercial perfume). The values of the root mean square error of prediction (RMSEP) and of the root mean square error of the percentage deviation (RMSPD) obtained were 0.4% (v/v) and 7.2%, respectively. Additionally, a second model was built and used to evaluate the accuracy of the method. A model to quantify the essential oil of lemon grass was built and its concentration was predicted in the validation set and real perfume samples. The RMSEP and RMSPD obtained were 0.5% (v/v) and 6.9%, respectively, and the concentration of the essential oil of lemon grass in perfume agreed to the value informed by the manufacturer. The result indicates that the MCR algorithm is adequate to resolve the target chromatogram from the complex sample and to build multivariate models of GC×GC-FID data. Copyright © 2011 Elsevier B.V. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Barba, M. Isabel [Group of Research in Applied Thermal Engineering-CREVER, Mechanical Engineering Dept. (Spain); Larrechi, M. Soledad, E-mail: mariasoledad.larrechi@urv.cat [Analytical and Organic Chemistry Dept., Universitat Rovira i Virgili, Tarragona (Spain); Coronas, Alberto [Group of Research in Applied Thermal Engineering-CREVER, Mechanical Engineering Dept. (Spain)
2016-05-05
The hydration process of lithium iodide, lithium bromide, lithium chloride and lithium nitrate in water was analyzed quantitatively by applying multivariate curve resolution alternating least squares (MCR-ALS) to their near infrared spectra recorded between 850 nm and 1100 nm. The experiments were carried out using solutions with a salt mass fraction between 0% and 72% for lithium bromide, between 0% and 67% for lithium nitrate and between 0% and 62% for lithium chloride and lithium iodide at 323.15 K, 333.15 K, 343.15 K and 353.15 K, respectively. Three factors were determined for lithium bromide and lithium iodide and two factors for the lithium chloride and lithium nitrate by singular value decomposition (SVD) of their spectral data matrices. These factors are associated with various chemical environments in which there are aqueous clusters containing the ions of the salts and non-coordinated water molecules. Spectra and concentration profiles of non-coordinated water and cluster aqueous were retrieved by MCR-ALS. The amount of water involved in the process of hydration of the various salts was quantified. The results show that the water absorption capacity increases in the following order LiI < LiBr < LiNO{sub 3} < LiCl. The salt concentration at which there is no free water in the medium was calculated at each one of the temperatures considered. The values ranged between 62.6 and 65.1% for LiBr, 45.5–48.3% for LiCl, 60.4–61.2% for LiI and 60.3–63.7% for LiNO{sub 3}. These values are an initial approach to determining the concentration as from which crystal formation is favored. - Highlights: • Quantitative analysis of the hydration of lithium salts in water. • The absorption capacity of the electrolytes in function of the salt is evaluated. • The lithium salt concentration is estimated when the crystal formation is favored.
International Nuclear Information System (INIS)
Barba, M. Isabel; Larrechi, M. Soledad; Coronas, Alberto
2016-01-01
The hydration process of lithium iodide, lithium bromide, lithium chloride and lithium nitrate in water was analyzed quantitatively by applying multivariate curve resolution alternating least squares (MCR-ALS) to their near infrared spectra recorded between 850 nm and 1100 nm. The experiments were carried out using solutions with a salt mass fraction between 0% and 72% for lithium bromide, between 0% and 67% for lithium nitrate and between 0% and 62% for lithium chloride and lithium iodide at 323.15 K, 333.15 K, 343.15 K and 353.15 K, respectively. Three factors were determined for lithium bromide and lithium iodide and two factors for the lithium chloride and lithium nitrate by singular value decomposition (SVD) of their spectral data matrices. These factors are associated with various chemical environments in which there are aqueous clusters containing the ions of the salts and non-coordinated water molecules. Spectra and concentration profiles of non-coordinated water and cluster aqueous were retrieved by MCR-ALS. The amount of water involved in the process of hydration of the various salts was quantified. The results show that the water absorption capacity increases in the following order LiI < LiBr < LiNO_3 < LiCl. The salt concentration at which there is no free water in the medium was calculated at each one of the temperatures considered. The values ranged between 62.6 and 65.1% for LiBr, 45.5–48.3% for LiCl, 60.4–61.2% for LiI and 60.3–63.7% for LiNO_3. These values are an initial approach to determining the concentration as from which crystal formation is favored. - Highlights: • Quantitative analysis of the hydration of lithium salts in water. • The absorption capacity of the electrolytes in function of the salt is evaluated. • The lithium salt concentration is estimated when the crystal formation is favored.
Kongklieng, Amornmas; Intapan, Pewpan M; Boonmars, Thidarut; Thanchomnang, Tongjit; Janwan, Penchom; Sanpool, Oranuch; Lulitanond, Viraphong; Taweethavonsawat, Piyanan; Chungpivat, Sudchit; Maleewong, Wanchai
2015-03-01
A real-time fluorescence resonance energy transfer polymerase chain reaction (qFRET PCR) coupled with melting curve analysis was developed for detection of Babesia canis vogeli and Hepatozoon canis infections in canine blood samples in a single tube assay. The target of the assay was a region within the 18S ribosomal RNA gene amplified in either species by a single pair of primers. Following amplification from the DNA of infected dog blood, a fluorescence melting curve analysis was done. The 2 species, B. canis vogeli and H. canis, could be detected and differentiated in infected dog blood samples (n = 37) with high sensitivity (100%). The detection limit for B. canis vogeli was 15 copies of a positive control plasmid, and for H. canis, it was 150 copies of a positive control plasmid. The assay could simultaneously distinguish the DNA of both parasites from the DNA of controls. Blood samples from 5 noninfected dogs were negative, indicating high specificity. Several samples can be run at the same time. The assay can reduce misdiagnosis and the time associated with microscopic examination, and is not prone to the carryover contamination associated with the agarose gel electrophoresis step of conventional PCR. In addition, this qFRET PCR method would be useful to accurately determine the range of endemic areas or to discover those areas where the 2 parasites co-circulate. © 2015 The Author(s).
Pinto, Licarion; Díaz Nieto, César Horacio; Zón, María Alicia; Fernández, Héctor; de Araujo, Mario Cesar Ugulino
2016-01-01
Biogenic amines (BAs) are used for identifying spoilage in food. The most common are tryptamine (TRY), 2-phenylethylamine (PHE), putrescine (PUT), cadaverine (CAD) and histamine (HIS). Due to lack of chromophores, chemical derivatization with dansyl was employed to analyze these BAs using high performance liquid chromatography with a diode array detector (HPLC-DAD). However, the derivatization reaction occurs with any primary or secondary amine, leading to co-elution of analytes and interferents with identical spectral profiles, and thus causing rank deficiency. When the spectral profile is the same and peak misalignment is present on the chromatographic runs, it is not possible to handle the data only with Multivariate Curve Resolution and Alternative Least Square (MCR-ALS), by augmenting the time, or the spectral mode. A way to circumvent this drawback is to receive information from another detector that leads to a selective profile for the analyte. To overcome both problems, (tri-linearity break in time, and spectral mode), this paper proposes a new analytical methodology for fast quantitation of these BAs in fish with HPLC-DAD by using the icoshift algorithm for temporal misalignment correction before MCR-ALS spectral mode augmented treatment. Limits of detection, relative errors of prediction (REP) and average recoveries, ranging from 0.14 to 0.50 µg mL(-1), 3.5-8.8% and 88.08%-99.68%, respectively. These are outstanding results obtained, reaching quantification limits for the five BAs much lower than those established by the Food and Agriculture Organization of the United Nations and World Health Organization (FAO/WHO), and the European Food Safety Authority (EFSA), all without any pre-concentration steps. The concentrations of BAs in fish samples ranged from 7.82 to 29.41 µg g(-1), 8.68-25.95 µg g(-1), 4.76-28.54 µg g(-1), 5.18-39.95 µg g(-1) and 1.45-52.62 µg g(-1) for TRY, PHE, PUT, CAD, and HIS, respectively. In addition, the proposed method spends
International Nuclear Information System (INIS)
Pinto, Licarion; Díaz Nieto, César Horacio; Zón, María Alicia; Fernández, Héctor; Ugulino de Araujo, Mario Cesar
2016-01-01
Biogenic amines (BAs) are used for identifying spoilage in food. The most common are tryptamine (TRY), 2-phenylethylamine (PHE), putrescine (PUT), cadaverine (CAD) and histamine (HIS). Due to lack of chromophores, chemical derivatization with dansyl was employed to analyze these BAs using high performance liquid chromatography with a diode array detector (HPLC-DAD). However, the derivatization reaction occurs with any primary or secondary amine, leading to co-elution of analytes and interferents with identical spectral profiles, and thus causing rank deficiency. When the spectral profile is the same and peak misalignment is present on the chromatographic runs, it is not possible to handle the data only with Multivariate Curve Resolution and Alternative Least Square (MCR-ALS), by augmenting the time, or the spectral mode. A way to circumvent this drawback is to receive information from another detector that leads to a selective profile for the analyte. To overcome both problems, (tri-linearity break in time, and spectral mode), this paper proposes a new analytical methodology for fast quantitation of these BAs in fish with HPLC-DAD by using the icoshift algorithm for temporal misalignment correction before MCR-ALS spectral mode augmented treatment. Limits of detection, relative errors of prediction (REP) and average recoveries, ranging from 0.14 to 0.50 µg mL"−"1, 3.5–8.8% and 88.08%–99.68%, respectively. These are outstanding results obtained, reaching quantification limits for the five BAs much lower than those established by the Food and Agriculture Organization of the United Nations and World Health Organization (FAO/WHO), and the European Food Safety Authority (EFSA), all without any pre-concentration steps. The concentrations of BAs in fish samples ranged from 7.82 to 29.41 µg g"−"1, 8.68–25.95 µg g"−"1, 4.76–28.54 µg g"−"1, 5.18–39.95 µg g"−"1 and 1.45–52.62 µg g"−"1 for TRY, PHE, PUT, CAD, and HIS, respectively. In
Energy Technology Data Exchange (ETDEWEB)
Pinto, Licarion [Laboratório de Automação e Instrumentação em Química Analítica e Quimiometria (LAQA), Universidade Federal da Paraíba, CCEN, Departamento de Química, Caixa Postal 5093, CEP 58051-970, João Pessoa, PB (Brazil); Díaz Nieto, César Horacio; Zón, María Alicia; Fernández, Héctor [Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, 5800, Río Cuarto (Argentina); Ugulino de Araujo, Mario Cesar, E-mail: laqa@quimica.ufpb.br [Laboratório de Automação e Instrumentação em Química Analítica e Quimiometria (LAQA), Universidade Federal da Paraíba, CCEN, Departamento de Química, Caixa Postal 5093, CEP 58051-970, João Pessoa, PB (Brazil)
2016-01-01
Biogenic amines (BAs) are used for identifying spoilage in food. The most common are tryptamine (TRY), 2-phenylethylamine (PHE), putrescine (PUT), cadaverine (CAD) and histamine (HIS). Due to lack of chromophores, chemical derivatization with dansyl was employed to analyze these BAs using high performance liquid chromatography with a diode array detector (HPLC-DAD). However, the derivatization reaction occurs with any primary or secondary amine, leading to co-elution of analytes and interferents with identical spectral profiles, and thus causing rank deficiency. When the spectral profile is the same and peak misalignment is present on the chromatographic runs, it is not possible to handle the data only with Multivariate Curve Resolution and Alternative Least Square (MCR-ALS), by augmenting the time, or the spectral mode. A way to circumvent this drawback is to receive information from another detector that leads to a selective profile for the analyte. To overcome both problems, (tri-linearity break in time, and spectral mode), this paper proposes a new analytical methodology for fast quantitation of these BAs in fish with HPLC-DAD by using the icoshift algorithm for temporal misalignment correction before MCR-ALS spectral mode augmented treatment. Limits of detection, relative errors of prediction (REP) and average recoveries, ranging from 0.14 to 0.50 µg mL{sup −1}, 3.5–8.8% and 88.08%–99.68%, respectively. These are outstanding results obtained, reaching quantification limits for the five BAs much lower than those established by the Food and Agriculture Organization of the United Nations and World Health Organization (FAO/WHO), and the European Food Safety Authority (EFSA), all without any pre-concentration steps. The concentrations of BAs in fish samples ranged from 7.82 to 29.41 µg g{sup −1}, 8.68–25.95 µg g{sup −1}, 4.76–28.54 µg g{sup −1}, 5.18–39.95 µg g{sup −1} and 1.45–52.62 µg g{sup −1} for TRY, PHE, PUT, CAD, and
Quantitative description of the magnetization curves of amorphous alloys of the series a-DyxGd1-xNi
International Nuclear Information System (INIS)
Barbara, B.; Filippi, J.; Amaral, V.S.
1992-01-01
The magnetization curves of the series of amorphous alloys Dy x Gd 1-x Ni measured between 1.5 and 4.2 K and up to 15 T, have been fitted to the zero kelvin analytical model of Chudnovsky. The results of these fits allow a detailed understanding of the magnetization curves of amorphous alloys with ferromagnetic interactions. In particular, the ratio D/J of the local anisotropy and exchange energies, and the magnetic and atomic correlation lengths, are accurately determined. (orig.)
Ignee, Andre; Jedrejczyk, Maciej; Schuessler, Gudrun; Jakubowski, Wieslaw; Dietrich, Christoph F
2010-01-01
Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. Videos sequences of 31 consecutive patients for at least 60s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10cm depths, whereas all other parameters showed only satisfying results at 4-6cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Ignee, Andre [Department of Internal Medicine and Diagnostic Imaging, Caritas Hospital, Uhlandstr. 7, 97990 Bad Mergentheim (Germany)], E-mail: andre.ignee@gmx.de; Jedrejczyk, Maciej [Department of Diagnostic Imaging, 2nd Division of Medical Faculty, Medical University, Ul. Kondratowicza 8, 03-242 Warsaw (Poland)], E-mail: mjedrzejczyk@interia.pl; Schuessler, Gudrun [Department of Internal Medicine and Diagnostic Imaging, Caritas Hospital, Uhlandstr. 7, 97990 Bad Mergentheim (Germany)], E-mail: gudrunschuessler@gmx.de; Jakubowski, Wieslaw [Department of Diagnostic Imaging, 2nd Division of Medical Faculty, Medical University, Ul. Kondratowicza 8, 03-242 Warsaw (Poland)], E-mail: ewajbmd@go2.pl; Dietrich, Christoph F. [Department of Internal Medicine and Diagnostic Imaging, Caritas Hospital, Uhlandstr. 7, 97990 Bad Mergentheim (Germany)], E-mail: christoph.dietrich@ckbm.de
2010-01-15
Introduction: Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. Patients and methods: Videos sequences of 31 consecutive patients for at least 60 s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. Results: The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10 cm depths, whereas all other parameters showed only satisfying results at 4-6 cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. Discussion: (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4 cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6 cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves.
International Nuclear Information System (INIS)
Ignee, Andre; Jedrejczyk, Maciej; Schuessler, Gudrun; Jakubowski, Wieslaw; Dietrich, Christoph F.
2010-01-01
Introduction: Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. Patients and methods: Videos sequences of 31 consecutive patients for at least 60 s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. Results: The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10 cm depths, whereas all other parameters showed only satisfying results at 4-6 cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. Discussion: (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4 cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6 cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves.
Tian, Dayong; Lin, Zhifen; Yin, Daqiang
2013-01-01
The present study proposed a QSAR model to predict joint effects at non-equitoxic ratios for binary mixtures containing reactive toxicants, cyanogenic compounds and aldehydes. Toxicity of single and binary mixtures was measured by quantifying the decrease in light emission from the Photobacterium phosphoreum for 15 min. The joint effects of binary mixtures (TU sum) can thus be obtained. The results showed that the relationships between toxic ratios of the individual chemicals and their joint effects can be described by normal distribution function. Based on normal distribution equations, the joint effects of binary mixtures at non-equitoxic ratios ( [Formula: see text]) can be predicted quantitatively using the joint effects at equitoxic ratios ( [Formula: see text]). Combined with a QSAR model of [Formula: see text]in our previous work, a novel QSAR model can be proposed to predict the joint effects of mixtures at non-equitoxic ratios ( [Formula: see text]). The proposed model has been validated using additional mixtures other than the one used for the development of the model. Predicted and observed results were similar (p>0.05). This study provides an approach to the prediction of joint effects for binary mixtures at non-equitoxic ratios.
Zhou, Huimin; Xiao, Qiaoling; Tan, Wen; Zhan, Yiyi; Pistolozzi, Marco
2017-09-10
Several molecules containing carbamate groups are metabolized by cholinesterases. This metabolism includes a time-dependent catalytic step which temporary inhibits the enzymes. In this paper we demonstrate that the analysis of the area under the inhibition versus time curve (AUIC) can be used to obtain a quantitative estimation of the amount of carbamate metabolized by the enzyme. (R)-bambuterol monocarbamate and plasma butyrylcholinesterase were used as model carbamate-cholinesterase system. The inhibition of different concentrations of the enzyme was monitored for 5h upon incubation with different concentrations of carbamate and the resulting AUICs were analyzed. The amount of carbamate metabolized could be estimated with cholinesterases in a selected compartment in which the cholinesterase is confined (e.g. in vitro solutions, tissues or body fluids), either in vitro or in vivo. Copyright © 2017 Elsevier B.V. All rights reserved.
Hofmann, Joerg; Frenzel, Katrin; Minh, Bui Q; von Haeseler, Arndt; Edelmann, Anke; Ross, Stefan R; Berg, Thomas; Krüger, Detlev H; Meisel, Helga
2010-06-01
Hepatitis D virus (HDV) infection is an important etiologic agent of fulminant hepatitis and may aggravate the clinical course of chronic hepatitis B infection resulting in cirrhosis and liver failure. This report describes the establishment of a real-time reverse transcriptase polymerase chain reaction method that allows the quantitative detection of HDV-1 and HDV-3 with a sensitivity in a linear range of 2 x 10(3) to 10(8) copies/mL. Additionally, the new assay provides the opportunity to distinguish HDV-1 from HDV-3 by a subsequent melting curve analysis, an important option because these HDV types are highly associated with severe clinical outcome. The results of the melting curve analysis of 42 HDV sequences obtained in this study and the phylogenetic analysis based on 139 full-length sequences from GenBank were consistent and showed that all sequences described here cluster within the HDV-1 clade. Therefore, this assay is useful for monitoring of antiviral treatment and molecular epidemiologic studies of HDV distribution. Copyright 2010 Elsevier Inc. All rights reserved.
U.S. Environmental Protection Agency — an UV calibration curve for SRHA quantitation. This dataset is associated with the following publication: Chang, X., and D. Bouchard. Surfactant-Wrapped Multiwalled...
Directory of Open Access Journals (Sweden)
Hiroyasu Umakoshi
Full Text Available To quantify the imaging findings of patients with interstitial pneumonia (IP and emphysema using three-dimensional curved high-resolution computed tomography (3D-cHRCT at a constant depth from the chest wall, and compare the results to visual assessment of IP and each patient's diffusing capacity of the lungs for carbon monoxide (DLco.We retrospectively reviewed the axial CT findings and pulmonary function test results of 95 patients with lung cancer (72 men and 23 women, aged 45-84 years with or without IP, as follows: non-IP (n = 47, mild IP (n = 31, and moderate IP (n = 17. The 3D-cHRCT images of the lung at a 1-cm depth from the chest wall were reconstructed automatically using original software; total area (TA, high-attenuation area (HAA >-500 HU, and low-attenuation area (LAA <-950 HU were calculated on a workstation. The %HAA and %LAA were calculated as follows: [Formula: see text], and [Formula: see text].The %HAA and %LAA respective values were 3.2±0.9 and 27.7±8.2, 3.9±1.2 and 27.6±5.9, and 6.9±2.2 and 25.4±8.7 in non-IP, mild IP, and moderate IP patients, respectively. There were significant differences in %HAA between the 3 groups of patients (P<0.001, but no differences in %LAA (P = 0.558. Multiple linear regression analysis revealed that %HAA and %LAA were negatively correlated with predicted DLco (standard partial regression coefficient [b*] = -0.453, P<0.001; b* = -0.447, P<0.001, respectively.The %HAA and %LAA values computed using 3D-cHRCT were significantly correlated with DLco and may be important quantitative parameters for both IP and emphysema.
Barbara, B.; Amaral, V. S.; Filippi, J.
1992-10-01
The magnetization curves of the series of amorphous alloys Dy xGd 1- xNi measured between 1.5 and 4.2 K and up to 15 T, have been fitted to the zero kelvin analytical model of Chudnovsky [1]. The results of these fits allow a detailed understanding of the magnetization curves of amorphous alloys with ferromagnetic interactions. In particular, the ratio D/ J of the local anisotropy and exchange energies, and the magnetic and atomic correlation lengths, are accurately determined.
Goodford, P J; St-Louis, J; Wootton, R
1978-01-01
1. Oxygen dissociation curves have been measured for human haemoglobin solutions with different concentrations of the allosteric effectors 2,3-diphosphoglycerate, adenosine triphosphate and inositol hexaphosphate. 2. Each effector produces a concentration dependent right shift of the oxygen dissociation curve, but a point is reached where the shift is maximal and increasing the effector concentration has no further effect. 3. Mathematical models based on the Monod, Wyman & Changeux (1965) treatment of allosteric proteins have been fitted to the data. For each compound the simple two-state model and its extension to take account of subunit inequivalence were shown to be inadequate, and a better fit was obtained by allowing the effector to lower the oxygen affinity of the deoxy conformational state as well as binding preferentially to this conformation. PMID:722582
International Nuclear Information System (INIS)
Martí-Aluja, Idoia; Ruisánchez, Itziar; Larrechi, M. Soledad
2013-01-01
Highlights: ► The structure of insulin can be changed via interaction with antiretroviral drugs. ► The chemical interaction promotes the formation of aggregates. ► This drug effect was evaluated by MCR-ALS coupled to IR spectroscopy. ► Formation of aggregates was favourable if drugs were able to form hydrogen bonds. ► Higher drug concentrations favoured formation of amorphous aggregates. - Abstract: Quantification of the effect of antiretroviral drugs on the insulin aggregation process is an important area of research due to the serious metabolic diseases observed in AIDS patients after prolonged treatment with these drugs. In this work, multivariate curve resolution alternating least squares (MCR-ALS) was applied to infrared monitoring of the insulin aggregation process in the presence of three antiretroviral drugs to quantify their effect. To evidence concentration dependence in this process, mixtures at two different insulin:drug molar ratios were used. The interaction between insulin and each drug was analysed by 1 H NMR spectroscopy. In all cases, the aggregation process was monitored during 45 min by infrared spectroscopy. The aggregates were further characterised by scanning electron microscopy (SEM). MCR-ALS provided the spectral and concentration profiles of the different insulin–drug conformations that are involved in the process. Their feasible band boundaries were calculated using the MCR-BANDS methodology. The kinetic profiles describe the aggregation pathway and the spectral profiles characterise the conformations involved. The retrieved results show that each of the three drugs modifies insulin conformation in a different way, promoting the formation of aggregates. Ritonavir shows the strongest promotion of aggregation, followed by efavirenz and zidovudine. In the studied concentration range, concentration dependence was only observed for zidovudine, with shorter aggregation time obtained as the amount of zidovudine increased. This factor
Xia, Qiangwei; Wang, Tiansong; Park, Yoonsuk; Lamont, Richard J.; Hackett, Murray
2007-01-01
Differential analysis of whole cell proteomes by mass spectrometry has largely been applied using various forms of stable isotope labeling. While metabolic stable isotope labeling has been the method of choice, it is often not possible to apply such an approach. Four different label free ways of calculating expression ratios in a classic "two-state" experiment are compared: signal intensity at the peptide level, signal intensity at the protein level, spectral counting at the peptide level, and spectral counting at the protein level. The quantitative data were mined from a dataset of 1245 qualitatively identified proteins, about 56% of the protein encoding open reading frames from Porphyromonas gingivalis, a Gram-negative intracellular pathogen being studied under extracellular and intracellular conditions. Two different control populations were compared against P. gingivalis internalized within a model human target cell line. The q-value statistic, a measure of false discovery rate previously applied to transcription microarrays, was applied to proteomics data. For spectral counting, the most logically consistent estimate of random error came from applying the locally weighted scatter plot smoothing procedure (LOWESS) to the most extreme ratios generated from a control technical replicate, thus setting upper and lower bounds for the region of experimentally observed random error.
Analysis of characteristic performance curves in radiodiagnosis by an observer
International Nuclear Information System (INIS)
Kossovoj, A.L.
1988-01-01
Methods and ways of construction of performance characteristic curves (PX-curves) in roentgenology, their qualitative and quantitative estimation are described. Estimation of PX curves application for analysis of scintigraphic and sonographic images is presented
A note on families of fragility curves
International Nuclear Information System (INIS)
Kaplan, S.; Bier, V.M.; Bley, D.C.
1989-01-01
In the quantitative assessment of seismic risk, uncertainty in the fragility of a structural component is usually expressed by putting forth a family of fragility curves, with probability serving as the parameter of the family. Commonly, a lognormal shape is used both for the individual curves and for the expression of uncertainty over the family. A so-called composite single curve can also be drawn and used for purposes of approximation. This composite curve is often regarded as equivalent to the mean curve of the family. The equality seems intuitively reasonable, but according to the authors has never been proven. The paper presented proves this equivalence hypothesis mathematically. Moreover, the authors show that this equivalence hypothesis between fragility curves is itself equivalent to an identity property of the standard normal probability curve. Thus, in the course of proving the fragility curve hypothesis, the authors have also proved a rather obscure, but interesting and perhaps previously unrecognized, property of the standard normal curve
51Cr - erythrocyte survival curves
International Nuclear Information System (INIS)
Paiva Costa, J. de.
1982-07-01
Sixteen patients were studied, being fifteen patients in hemolytic state, and a normal individual as a witness. The aim was to obtain better techniques for the analysis of the erythrocytes, survival curves, according to the recommendations of the International Committee of Hematology. It was used the radiochromatic method as a tracer. Previously a revisional study of the International Literature was made in its aspects inherent to the work in execution, rendering possible to establish comparisons and clarify phonomena observed in cur investigation. Several parameters were considered in this study, hindering both the exponential and the linear curves. The analysis of the survival curves of the erythrocytes in the studied group, revealed that the elution factor did not present a homogeneous answer quantitatively to all, though, the result of the analysis of these curves have been established, through listed programs in the electronic calculator. (Author) [pt
Rouleau, Etienne; Lefol, Cédrick; Bourdon, Violaine; Coulet, Florence; Noguchi, Tetsuro; Soubrier, Florent; Bièche, Ivan; Olschwang, Sylviane; Sobol, Hagay; Lidereau, Rosette
2009-06-01
Several techniques have been developed to screen mismatch repair (MMR) genes for deleterious mutations. Until now, two different techniques were required to screen for both point mutations and large rearrangements. For the first time, we propose a new approach, called "quantitative PCR (qPCR) high-resolution melting (HRM) curve analysis (qPCR-HRM)," which combines qPCR and HRM to obtain a rapid and cost-effective method suitable for testing a large series of samples. We designed PCR amplicons to scan the MLH1 gene using qPCR HRM. Seventy-six patients were fully scanned in replicate, including 14 wild-type patients and 62 patients with known mutations (57 point mutations and five rearrangements). To validate the detected mutations, we used sequencing and/or hybridization on a dedicated MLH1 array-comparative genomic hybridization (array-CGH). All point mutations and rearrangements detected by denaturing high-performance liquid chromatography (dHPLC)+multiplex ligation-dependent probe amplification (MLPA) were successfully detected by qPCR HRM. Three large rearrangements were characterized with the dedicated MLH1 array-CGH. One variant was detected with qPCR HRM in a wild-type patient and was located within the reverse primer. One variant was not detected with qPCR HRM or with dHPLC due to its proximity to a T-stretch. With qPCR HRM, prescreening for point mutations and large rearrangements are performed in one tube and in one step with a single machine, without the need for any automated sequencer in the prescreening process. In replicate, its reagent cost, sensitivity, and specificity are comparable to those of dHPLC+MLPA techniques. However, qPCR HRM outperformed the other techniques in terms of its rapidity and amount of data provided.
Lagrangian Curves on Spectral Curves of Monopoles
International Nuclear Information System (INIS)
Guilfoyle, Brendan; Khalid, Madeeha; Ramon Mari, Jose J.
2010-01-01
We study Lagrangian points on smooth holomorphic curves in TP 1 equipped with a natural neutral Kaehler structure, and prove that they must form real curves. By virtue of the identification of TP 1 with the space LE 3 of oriented affine lines in Euclidean 3-space, these Lagrangian curves give rise to ruled surfaces in E 3 , which we prove have zero Gauss curvature. Each ruled surface is shown to be the tangent lines to a curve in E 3 , called the edge of regression of the ruled surface. We give an alternative characterization of these curves as the points in E 3 where the number of oriented lines in the complex curve Σ that pass through the point is less than the degree of Σ. We then apply these results to the spectral curves of certain monopoles and construct the ruled surfaces and edges of regression generated by the Lagrangian curves.
DEFF Research Database (Denmark)
Bernstein, Daniel J.; Birkner, Peter; Lange, Tanja
2013-01-01
-arithmetic level are as follows: (1) use Edwards curves instead of Montgomery curves; (2) use extended Edwards coordinates; (3) use signed-sliding-window addition-subtraction chains; (4) batch primes to increase the window size; (5) choose curves with small parameters and base points; (6) choose curves with large...
Quantitative analysis chemistry
International Nuclear Information System (INIS)
Ko, Wansuk; Lee, Choongyoung; Jun, Kwangsik; Hwang, Taeksung
1995-02-01
This book is about quantitative analysis chemistry. It is divided into ten chapters, which deal with the basic conception of material with the meaning of analysis chemistry and SI units, chemical equilibrium, basic preparation for quantitative analysis, introduction of volumetric analysis, acid-base titration of outline and experiment examples, chelate titration, oxidation-reduction titration with introduction, titration curve, and diazotization titration, precipitation titration, electrometric titration and quantitative analysis.
Directory of Open Access Journals (Sweden)
Janusz Charatonik
1991-11-01
Full Text Available Results concerning contractibility of curves (equivalently: of dendroids are collected and discussed in the paper. Interrelations tetween various conditions which are either sufficient or necessary for a curve to be contractible are studied.
Curvature Entropy for Curved Profile Generation
Ujiie, Yoshiki; Kato, Takeo; Sato, Koichiro; Matsuoka, Yoshiyuki
2012-01-01
In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribu...
Directory of Open Access Journals (Sweden)
René Pellissier
2012-01-01
Full Text Available This paper explores the notion ofjump ing the curve,following from Handy 's S-curve onto a new curve with new rules policies and procedures. . It claims that the curve does not generally lie in wait but has to be invented by leadership. The focus of this paper is the identification (mathematically and inferentially ofthat point in time, known as the cusp in catastrophe theory, when it is time to change - pro-actively, pre-actively or reactively. These three scenarios are addressed separately and discussed in terms ofthe relevance ofeach.
Martínez, Sol Sáez; de la Rosa, Félix Martínez; Rojas, Sergio
2017-01-01
In Advanced Calculus, our students wonder if it is possible to graphically represent a tornado by means of a three-dimensional curve. In this paper, we show it is possible by providing the parametric equations of such tornado-shaped curves.
Simulating Supernova Light Curves
International Nuclear Information System (INIS)
Even, Wesley Paul; Dolence, Joshua C.
2016-01-01
This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth's atmosphere.
Simulating Supernova Light Curves
Energy Technology Data Exchange (ETDEWEB)
Even, Wesley Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dolence, Joshua C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-05-05
This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.
Image scaling curve generation
2012-01-01
The present invention relates to a method of generating an image scaling curve, where local saliency is detected in a received image. The detected local saliency is then accumulated in the first direction. A final scaling curve is derived from the detected local saliency and the image is then
Image scaling curve generation.
2011-01-01
The present invention relates to a method of generating an image scaling curve, where local saliency is detected in a received image. The detected local saliency is then accumulated in the first direction. A final scaling curve is derived from the detected local saliency and the image is then
Tempo curves considered harmful
Desain, P.; Honing, H.
1993-01-01
In the literature of musicology, computer music research and the psychology of music, timing or tempo measurements are mostly presented in the form of continuous curves. The notion of these tempo curves is dangerous, despite its widespread use, because it lulls its users into the false impression
Chou, Kai-Seng
2001-01-01
Although research in curve shortening flow has been very active for nearly 20 years, the results of those efforts have remained scattered throughout the literature. For the first time, The Curve Shortening Problem collects and illuminates those results in a comprehensive, rigorous, and self-contained account of the fundamental results.The authors present a complete treatment of the Gage-Hamilton theorem, a clear, detailed exposition of Grayson''s convexity theorem, a systematic discussion of invariant solutions, applications to the existence of simple closed geodesics on a surface, and a new, almost convexity theorem for the generalized curve shortening problem.Many questions regarding curve shortening remain outstanding. With its careful exposition and complete guide to the literature, The Curve Shortening Problem provides not only an outstanding starting point for graduate students and new investigations, but a superb reference that presents intriguing new results for those already active in the field.
Directory of Open Access Journals (Sweden)
Paulo Prochno
2004-07-01
Full Text Available Learning curves have been studied for a long time. These studies provided strong support to the hypothesis that, as organizations produce more of a product, unit costs of production decrease at a decreasing rate (see Argote, 1999 for a comprehensive review of learning curve studies. But the organizational mechanisms that lead to these results are still underexplored. We know some drivers of learning curves (ADLER; CLARK, 1991; LAPRE et al., 2000, but we still lack a more detailed view of the organizational processes behind those curves. Through an ethnographic study, I bring a comprehensive account of the first year of operations of a new automotive plant, describing what was taking place on in the assembly area during the most relevant shifts of the learning curve. The emphasis is then on how learning occurs in that setting. My analysis suggests that the overall learning curve is in fact the result of an integration process that puts together several individual ongoing learning curves in different areas throughout the organization. In the end, I propose a model to understand the evolution of these learning processes and their supporting organizational mechanisms.
Buonanno, Paolo; Fergusson, Leopoldo; Vargas, Juan Fernando
2014-01-01
We document the existence of a Crime Kuznets Curve in US states since the 1970s. As income levels have risen, crime has followed an inverted U-shaped pattern, first increasing and then dropping. The Crime Kuznets Curve is not explained by income inequality. In fact, we show that during the sample period inequality has risen monotonically with income, ruling out the traditional Kuznets Curve. Our finding is robust to adding a large set of controls that are used in the literature to explain the...
Directory of Open Access Journals (Sweden)
Kožul Nataša
2014-01-01
Full Text Available In the broadest sense, yield curve indicates the market's view of the evolution of interest rates over time. However, given that cost of borrowing it closely linked to creditworthiness (ability to repay, different yield curves will apply to different currencies, market sectors, or even individual issuers. As government borrowing is indicative of interest rate levels available to other market players in a particular country, and considering that bond issuance still remains the dominant form of sovereign debt, this paper describes yield curve construction using bonds. The relationship between zero-coupon yield, par yield and yield to maturity is given and their usage in determining curve discount factors is described. Their usage in deriving forward rates and pricing related derivative instruments is also discussed.
International Nuclear Information System (INIS)
Gruhn, C.R.
1981-05-01
An alternative utilization is presented for the gaseous ionization chamber in the detection of energetic heavy ions, which is called Bragg Curve Spectroscopy (BCS). Conceptually, BCS involves using the maximum data available from the Bragg curve of the stopping heavy ion (HI) for purposes of identifying the particle and measuring its energy. A detector has been designed that measures the Bragg curve with high precision. From the Bragg curve the range from the length of the track, the total energy from the integral of the specific ionization over the track, the dE/dx from the specific ionization at the beginning of the track, and the Bragg peak from the maximum of the specific ionization of the HI are determined. This last signal measures the atomic number, Z, of the HI unambiguously
Directory of Open Access Journals (Sweden)
Sutawanir Darwis
2012-05-01
Full Text Available Empirical decline curve analysis of oil production data gives reasonable answer in hyperbolic type curves situations; however the methodology has limitations in fitting real historical production data in present of unusual observations due to the effect of the treatment to the well in order to increase production capacity. The development ofrobust least squares offers new possibilities in better fitting production data using declinecurve analysis by down weighting the unusual observations. This paper proposes a robustleast squares fitting lmRobMM approach to estimate the decline rate of daily production data and compares the results with reservoir simulation results. For case study, we usethe oil production data at TBA Field West Java. The results demonstrated that theapproach is suitable for decline curve fitting and offers a new insight in decline curve analysis in the present of unusual observations.
DEFF Research Database (Denmark)
Georgieva Yankova, Ginka; Federici, Paolo
This report describes power curve measurements carried out on a given turbine in a chosen period. The measurements are carried out in accordance to IEC 61400-12-1 Ed. 1 and FGW Teil 2.......This report describes power curve measurements carried out on a given turbine in a chosen period. The measurements are carried out in accordance to IEC 61400-12-1 Ed. 1 and FGW Teil 2....
Alexeev, Valery; Clemens, C Herbert; Beauville, Arnaud
2008-01-01
This book is devoted to recent progress in the study of curves and abelian varieties. It discusses both classical aspects of this deep and beautiful subject as well as two important new developments, tropical geometry and the theory of log schemes. In addition to original research articles, this book contains three surveys devoted to singularities of theta divisors, of compactified Jacobians of singular curves, and of "strange duality" among moduli spaces of vector bundles on algebraic varieties.
International Nuclear Information System (INIS)
Mostbeck, A.; Lofferer, O.; Kahn, P.; Partsch, H.; Koehn, H.; Bialonczyk, Ch.; Koenig, B.
1984-01-01
Labelled colloids and macromolecules are removed lymphatically. The uptake of tracer in the regional lymphnodes is a parameter of lymphatic flow. Due to great variations in patient shape - obesity, cachexia - and accompanying variations in counting efficiencies quantitative measurements with reasonable accuracy have not been reported to date. A new approach to regional absorption correction is based on the combination of transmission and emission scans for each patient. The transmission scan is used for calculation of an absorption correction matrix. Accurate superposition of the correction matrix and the emission scan is achieved by computing the centers of gravity of point sources and - in the case of aligning opposite views - by cross correlation of binary images. In phantom studies the recovery was high (98.3%) and the coefficient of variation of repeated measurement below 1%. In patient studies a standardized stress is a prerequisite for reliable and comparable results. Discrimination between normals (14.3 +- 4.2D%) and patients with lymphedema (2.05 +- 2.5D%) was highly significant using praefascial lymphography and sc injection. Clearence curve analysis of the activities at the injection site, however, gave no reliable data for this purpose. In normals, the uptake in lymphnodes after im injection is by one order of magnitude lower then the uptake after sc injection. The discrimination between normals and patients with postthromboic syndrome was significant. Lymphography after ic injection was in the normal range in 2/3 of the patients with lymphedema and is therefore of no diagnostic value. The difference in uptake after ic and sc injection demonstrated for the first time by our quantitative method provides new insights into the pathophysiology of lymphedema and needs further investigation. (Author)
Approximation by planar elastic curves
DEFF Research Database (Denmark)
Brander, David; Gravesen, Jens; Nørbjerg, Toke Bjerge
2016-01-01
We give an algorithm for approximating a given plane curve segment by a planar elastic curve. The method depends on an analytic representation of the space of elastic curve segments, together with a geometric method for obtaining a good initial guess for the approximating curve. A gradient......-driven optimization is then used to find the approximating elastic curve....
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Vesth, Allan
This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here, the refere......This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here......, the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...
Curved electromagnetic missiles
International Nuclear Information System (INIS)
Myers, J.M.; Shen, H.M.; Wu, T.T.
1989-01-01
Transient electromagnetic fields can exhibit interesting behavior in the limit of great distances from their sources. In situations of finite total radiated energy, the energy reaching a distant receiver can decrease with distance much more slowly than the usual r - 2 . Cases of such slow decrease have been referred to as electromagnetic missiles. All of the wide variety of known missiles propagate in essentially straight lines. A sketch is presented here of a missile that can follow a path that is strongly curved. An example of a curved electromagnetic missile is explicitly constructed and some of its properties are discussed. References to details available elsewhere are given
Algebraic curves and cryptography
Murty, V Kumar
2010-01-01
It is by now a well-known paradigm that public-key cryptosystems can be built using finite Abelian groups and that algebraic geometry provides a supply of such groups through Abelian varieties over finite fields. Of special interest are the Abelian varieties that are Jacobians of algebraic curves. All of the articles in this volume are centered on the theme of point counting and explicit arithmetic on the Jacobians of curves over finite fields. The topics covered include Schoof's \\ell-adic point counting algorithm, the p-adic algorithms of Kedlaya and Denef-Vercauteren, explicit arithmetic on
IGMtransmission: Transmission curve computation
Harrison, Christopher M.; Meiksin, Avery; Stock, David
2015-04-01
IGMtransmission is a Java graphical user interface that implements Monte Carlo simulations to compute the corrections to colors of high-redshift galaxies due to intergalactic attenuation based on current models of the Intergalactic Medium. The effects of absorption due to neutral hydrogen are considered, with particular attention to the stochastic effects of Lyman Limit Systems. Attenuation curves are produced, as well as colors for a wide range of filter responses and model galaxy spectra. Photometric filters are included for the Hubble Space Telescope, the Keck telescope, the Mt. Palomar 200-inch, the SUBARU telescope and UKIRT; alternative filter response curves and spectra may be readily uploaded.
Learning from uncertain curves
DEFF Research Database (Denmark)
Mallasto, Anton; Feragen, Aasa
2017-01-01
We introduce a novel framework for statistical analysis of populations of nondegenerate Gaussian processes (GPs), which are natural representations of uncertain curves. This allows inherent variation or uncertainty in function-valued data to be properly incorporated in the population analysis. Us...
DEFF Research Database (Denmark)
Federici, Paolo; Kock, Carsten Weber
This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...
DEFF Research Database (Denmark)
Vesth, Allan; Kock, Carsten Weber
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....
DEFF Research Database (Denmark)
Federici, Paolo; Vesth, Allan
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....
DEFF Research Database (Denmark)
Villanueva, Héctor; Gómez Arranz, Paula
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine...
Groot, L.F.M.|info:eu-repo/dai/nl/073642398
2008-01-01
The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across
Hunter, Walter M.
This document contains detailed directions for constructing a device that mechanically produces the three-dimensional shape resulting from the rotation of any algebraic line or curve around either axis on the coordinate plant. The device was developed in response to student difficulty in visualizing, and thus grasping the mathematical principles…
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Wagner, Rozenn
This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...
DEFF Research Database (Denmark)
Vesth, Allan; Kock, Carsten Weber
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...
Textbook Factor Demand Curves.
Davis, Joe C.
1994-01-01
Maintains that teachers and textbook graphics follow the same basic pattern in illustrating changes in demand curves when product prices increase. Asserts that the use of computer graphics will enable teachers to be more precise in their graphic presentation of price elasticity. (CFR)
Bernstein, D.J.; Birkner, P.; Lange, T.; Peters, C.P.
2013-01-01
This paper introduces EECM-MPFQ, a fast implementation of the elliptic-curve method of factoring integers. EECM-MPFQ uses fewer modular multiplications than the well-known GMP-ECM software, takes less time than GMP-ECM, and finds more primes than GMP-ECM. The main improvements above the
DEFF Research Database (Denmark)
Federici, Paolo; Kock, Carsten Weber
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine...
Walker, Judy L
2000-01-01
When information is transmitted, errors are likely to occur. Coding theory examines efficient ways of packaging data so that these errors can be detected, or even corrected. The traditional tools of coding theory have come from combinatorics and group theory. Lately, however, coding theorists have added techniques from algebraic geometry to their toolboxes. In particular, by re-interpreting the Reed-Solomon codes, one can see how to define new codes based on divisors on algebraic curves. For instance, using modular curves over finite fields, Tsfasman, Vladut, and Zink showed that one can define a sequence of codes with asymptotically better parameters than any previously known codes. This monograph is based on a series of lectures the author gave as part of the IAS/PCMI program on arithmetic algebraic geometry. Here, the reader is introduced to the exciting field of algebraic geometric coding theory. Presenting the material in the same conversational tone of the lectures, the author covers linear codes, inclu...
Energy Technology Data Exchange (ETDEWEB)
Groot, L. [Utrecht University, Utrecht School of Economics, Janskerkhof 12, 3512 BL Utrecht (Netherlands)
2008-11-15
The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across countries. These tools allow policy-makers and the general public to grasp at a single glance the impact of conventional distribution rules such as equal caps or grandfathering, or more sophisticated ones, on the distribution of greenhouse gas emissions. Second, using the Samuelson rule for the optimal provision of a public good, the Pareto-optimal distribution of carbon emissions is compared with the distribution that follows if countries follow Nash-Cournot abatement strategies. It is shown that the Pareto-optimal distribution under the Samuelson rule can be approximated by the equal cap division, represented by the diagonal in the Lorenz curve diagram.
Pelce, Pierre
1989-01-01
In recent years, much progress has been made in the understanding of interface dynamics of various systems: hydrodynamics, crystal growth, chemical reactions, and combustion. Dynamics of Curved Fronts is an important contribution to this field and will be an indispensable reference work for researchers and graduate students in physics, applied mathematics, and chemical engineering. The book consist of a 100 page introduction by the editor and 33 seminal articles from various disciplines.
David G. Blanchflower; Andrew J. Oswald
1992-01-01
The paper provides evidence for the existence of a negatively sloped locus linking the level of pay to the rate of regional (or industry) unemployment. This "wage curve" is estimated using microeconomic data for Britain, the US, Canada, Korea, Austria, Italy, Holland, Switzerland, Norway, and Germany, The average unemployment elasticity of pay is approximately -0.1. The paper sets out a multi-region efficiency wage model and argues that its predictions are consistent with the data.
Anatomical curve identification
Bowman, Adrian W.; Katina, Stanislav; Smith, Joanna; Brown, Denise
2015-01-01
Methods for capturing images in three dimensions are now widely available, with stereo-photogrammetry and laser scanning being two common approaches. In anatomical studies, a number of landmarks are usually identified manually from each of these images and these form the basis of subsequent statistical analysis. However, landmarks express only a very small proportion of the information available from the images. Anatomically defined curves have the advantage of providing a much richer expression of shape. This is explored in the context of identifying the boundary of breasts from an image of the female torso and the boundary of the lips from a facial image. The curves of interest are characterised by ridges or valleys. Key issues in estimation are the ability to navigate across the anatomical surface in three-dimensions, the ability to recognise the relevant boundary and the need to assess the evidence for the presence of the surface feature of interest. The first issue is addressed by the use of principal curves, as an extension of principal components, the second by suitable assessment of curvature and the third by change-point detection. P-spline smoothing is used as an integral part of the methods but adaptations are made to the specific anatomical features of interest. After estimation of the boundary curves, the intermediate surfaces of the anatomical feature of interest can be characterised by surface interpolation. This allows shape variation to be explored using standard methods such as principal components. These tools are applied to a collection of images of women where one breast has been reconstructed after mastectomy and where interest lies in shape differences between the reconstructed and unreconstructed breasts. They are also applied to a collection of lip images where possible differences in shape between males and females are of interest. PMID:26041943
Estimating Corporate Yield Curves
Antionio Diaz; Frank Skinner
2001-01-01
This paper represents the first study of retail deposit spreads of UK financial institutions using stochastic interest rate modelling and the market comparable approach. By replicating quoted fixed deposit rates using the Black Derman and Toy (1990) stochastic interest rate model, we find that the spread between fixed and variable rates of interest can be modeled (and priced) using an interest rate swap analogy. We also find that we can estimate an individual bank deposit yield curve as a spr...
Vo, Martin
2017-08-01
Light Curves Classifier uses data mining and machine learning to obtain and classify desired objects. This task can be accomplished by attributes of light curves or any time series, including shapes, histograms, or variograms, or by other available information about the inspected objects, such as color indices, temperatures, and abundances. After specifying features which describe the objects to be searched, the software trains on a given training sample, and can then be used for unsupervised clustering for visualizing the natural separation of the sample. The package can be also used for automatic tuning parameters of used methods (for example, number of hidden neurons or binning ratio). Trained classifiers can be used for filtering outputs from astronomical databases or data stored locally. The Light Curve Classifier can also be used for simple downloading of light curves and all available information of queried stars. It natively can connect to OgleII, OgleIII, ASAS, CoRoT, Kepler, Catalina and MACHO, and new connectors or descriptors can be implemented. In addition to direct usage of the package and command line UI, the program can be used through a web interface. Users can create jobs for ”training” methods on given objects, querying databases and filtering outputs by trained filters. Preimplemented descriptors, classifier and connectors can be picked by simple clicks and their parameters can be tuned by giving ranges of these values. All combinations are then calculated and the best one is used for creating the filter. Natural separation of the data can be visualized by unsupervised clustering.
Uniformization of elliptic curves
Ülkem, Özge; Ulkem, Ozge
2015-01-01
Every elliptic curve E defined over C is analytically isomorphic to C*=qZ for some q ∊ C*. Similarly, Tate has shown that if E is defined over a p-adic field K, then E is analytically isomorphic to K*=qZ for some q ∊ K . Further the isomorphism E(K) ≅ K*/qZ respects the action of the Galois group GK/K, where K is the algebraic closure of K. I will explain the construction of this isomorphism.
Roc curves for continuous data
Krzanowski, Wojtek J
2009-01-01
Since ROC curves have become ubiquitous in many application areas, the various advances have been scattered across disparate articles and texts. ROC Curves for Continuous Data is the first book solely devoted to the subject, bringing together all the relevant material to provide a clear understanding of how to analyze ROC curves.The fundamental theory of ROC curvesThe book first discusses the relationship between the ROC curve and numerous performance measures and then extends the theory into practice by describing how ROC curves are estimated. Further building on the theory, the authors prese
International Nuclear Information System (INIS)
Dobrowolski, Tomasz
2012-01-01
The constant curvature one and quasi-one dimensional Josephson junction is considered. On the base of Maxwell equations, the sine–Gordon equation that describes an influence of curvature on the kink motion was obtained. It is showed that the method of geometrical reduction of the sine–Gordon model from three to lower dimensional manifold leads to an identical form of the sine–Gordon equation. - Highlights: ► The research on dynamics of the phase in a curved Josephson junction is performed. ► The geometrical reduction is applied to the sine–Gordon model. ► The results of geometrical reduction and the fundamental research are compared.
Directory of Open Access Journals (Sweden)
Je Hyun Baekt
2000-01-01
Full Text Available A numerical study is conducted on the fully-developed laminar flow of an incompressible viscous fluid in a square duct rotating about a perpendicular axis to the axial direction of the duct. At the straight duct, the rotation produces vortices due to the Coriolis force. Generally two vortex cells are formed and the axial velocity distribution is distorted by the effect of this Coriolis force. When a convective force is weak, two counter-rotating vortices are shown with a quasi-parabolic axial velocity profile for weak rotation rates. As the rotation rate increases, the axial velocity on the vertical centreline of the duct begins to flatten and the location of vorticity center is moved near to wall by the effect of the Coriolis force. When the convective inertia force is strong, a double-vortex secondary flow appears in the transverse planes of the duct for weak rotation rates but as the speed of rotation increases the secondary flow is shown to split into an asymmetric configuration of four counter-rotating vortices. If the rotation rates are increased further, the secondary flow restabilizes to a slightly asymmetric double-vortex configuration. Also, a numerical study is conducted on the laminar flow of an incompressible viscous fluid in a 90°-bend square duct that rotates about axis parallel to the axial direction of the inlet. At a 90°-bend square duct, the feature of flow by the effect of a Coriolis force and a centrifugal force, namely a secondary flow by the centrifugal force in the curved region and the Coriolis force in the downstream region, is shown since the centrifugal force in curved region and the Coriolis force in downstream region are dominant respectively.
Elliptic curves for applications (Tutorial)
Lange, T.; Bernstein, D.J.; Chatterjee, S.
2011-01-01
More than 25 years ago, elliptic curves over finite fields were suggested as a group in which the Discrete Logarithm Problem (DLP) can be hard. Since then many researchers have scrutinized the security of the DLP on elliptic curves with the result that for suitably chosen curves only exponential
Titration Curves: Fact and Fiction.
Chamberlain, John
1997-01-01
Discusses ways in which datalogging equipment can enable titration curves to be measured accurately and how computing power can be used to predict the shape of curves. Highlights include sources of error, use of spreadsheets to generate titration curves, titration of a weak acid with a strong alkali, dibasic acids, weak acid and weak base, and…
Directory of Open Access Journals (Sweden)
Sergey A. Cherkis
2007-03-01
Full Text Available A typical solution of an integrable system is described in terms of a holomorphic curve and a line bundle over it. The curve provides the action variables while the time evolution is a linear flow on the curve's Jacobian. Even though the system of Nahm equations is closely related to the Hitchin system, the curves appearing in these two cases have very different nature. The former can be described in terms of some classical scattering problem while the latter provides a solution to some Seiberg-Witten gauge theory. This note identifies the setup in which one can formulate the question of relating the two curves.
Analysis of threshold curves for superconducting interferometers
International Nuclear Information System (INIS)
Peterson, R.L.; Hamilton, C.A.
1979-01-01
Threshold curves for multijunction superconducting interferometers have been calculated previously, showing general agreement with observed features, especially in symmetric cases. We here add some more details to the analysis, paying particular attention to the effects of asymmetries in coupling, inductance, or critical currents. Feed-loop inductance and flux quantization in the feed loop can be important. A changing lobe pattern over many periods, asymmetries within a period, shifting patterns between runs spanning a warm-up, and sudden changes in pattern because of noise in the environment are all quantitatively explainable on the basis of this model. By use of a single ''calibration curve'', the inductance for symmetric two- or three-junction interferometers can be obtained immediately
Curvature Entropy for Curved Profile Generation
Directory of Open Access Journals (Sweden)
Koichiro Sato
2012-03-01
Full Text Available In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribution, and represents the complexity of a shape (one of the overall shape features. The quadrature curvature entropy is an improvement of the curvature entropy by introducing a Markov process to evaluate the continuity of a curvature and to approximate human cognition of the shape. Additionally, a shape generation method using a genetic algorithm as a calculator and the entropy as a shape generation index is presented. Finally, the applicability of the proposed method is demonstrated using the side view of an automobile as a design example.
Johnson, L. E.; Kim, J.; Cifelli, R.; Chandra, C. V.
2016-12-01
Potential water retention, S, is one of parameters commonly used in hydrologic modeling for soil moisture accounting. Physically, S indicates total amount of water which can be stored in soil and is expressed in units of depth. S can be represented as a change of soil moisture content and in this context is commonly used to estimate direct runoff, especially in the Soil Conservation Service (SCS) curve number (CN) method. Generally, the lumped and the distributed hydrologic models can easily use the SCS-CN method to estimate direct runoff. Changes in potential water retention have been used in previous SCS-CN studies; however, these studies have focused on long-term hydrologic simulations where S is allowed to vary at the daily time scale. While useful for hydrologic events that span multiple days, the resolution is too coarse for short-term applications such as flash flood events where S may not recover its full potential. In this study, a new method for estimating a time-variable potential water retention at hourly time-scales is presented. The methodology is applied for the Napa River basin, California. The streamflow gage at St Helena, located in the upper reaches of the basin, is used as the control gage site to evaluate the model performance as it is has minimal influences by reservoirs and diversions. Rainfall events from 2011 to 2012 are used for estimating the event-based SCS CN to transfer to S. As a result, we have derived the potential water retention curve and it is classified into three sections depending on the relative change in S. The first is a negative slope section arising from the difference in the rate of moving water through the soil column, the second is a zero change section representing the initial recovery the potential water retention, and the third is a positive change section representing the full recovery of the potential water retention. Also, we found that the soil water moving has traffic jam within 24 hours after finished first
Energy Technology Data Exchange (ETDEWEB)
Lippoldt, Stefan
2016-01-21
In this thesis we study a formulation of Dirac fermions in curved spacetime that respects general coordinate invariance as well as invariance under local spin base transformations. We emphasize the advantages of the spin base invariant formalism both from a conceptual as well as from a practical viewpoint. This suggests that local spin base invariance should be added to the list of (effective) properties of (quantum) gravity theories. We find support for this viewpoint by the explicit construction of a global realization of the Clifford algebra on a 2-sphere which is impossible in the spin-base non-invariant vielbein formalism. The natural variables for this formulation are spacetime-dependent Dirac matrices subject to the Clifford-algebra constraint. In particular, a coframe, i.e. vielbein field is not required. We disclose the hidden spin base invariance of the vielbein formalism. Explicit formulas for the spin connection as a function of the Dirac matrices are found. This connection consists of a canonical part that is completely fixed in terms of the Dirac matrices and a free part that can be interpreted as spin torsion. The common Lorentz symmetric gauge for the vielbein is constructed for the Dirac matrices, even for metrics which are not linearly connected. Under certain criteria, it constitutes the simplest possible gauge, demonstrating why this gauge is so useful. Using the spin base formulation for building a field theory of quantized gravity and matter fields, we show that it suffices to quantize the metric and the matter fields. This observation is of particular relevance for field theory approaches to quantum gravity, as it can serve for a purely metric-based quantization scheme for gravity even in the presence of fermions. Hence, in the second part of this thesis we critically examine the gauge, and the field-parametrization dependence of renormalization group flows in the vicinity of non-Gaussian fixed points in quantum gravity. While physical
Astborg, Johan
2013-01-01
To develop your confidence in F#, this tutorial will first introduce you to simpler tasks such as curve fitting. You will then advance to more complex tasks such as implementing algorithms for trading semi-automation in a practical scenario-based format.If you are a data analyst or a practitioner in quantitative finance, economics, or mathematics and wish to learn how to use F# as a functional programming language, this book is for you. You should have a basic conceptual understanding of financial concepts and models. Elementary knowledge of the .NET framework would also be helpful.
Sadek, Mohammad
2010-01-01
In this thesis we give insight into the minimisation problem of genus one curves defined by equations other than Weierstrass equations. We are interested in genus one curves given as double covers of P1, plane cubics, or complete intersections of two quadrics in P3. By minimising such a curve we mean making the invariants associated to its defining equations as small as possible using a suitable change of coordinates. We study the non-uniqueness of minimisations of the genus one curves des...
Quantum fields in curved space
International Nuclear Information System (INIS)
Birrell, N.D.; Davies, P.C.W.
1982-01-01
The book presents a comprehensive review of the subject of gravitational effects in quantum field theory. Quantum field theory in Minkowski space, quantum field theory in curved spacetime, flat spacetime examples, curved spacetime examples, stress-tensor renormalization, applications of renormalization techniques, quantum black holes and interacting fields are all discussed in detail. (U.K.)
Extended analysis of cooling curves
International Nuclear Information System (INIS)
Djurdjevic, M.B.; Kierkus, W.T.; Liliac, R.E.; Sokolowski, J.H.
2002-01-01
Thermal Analysis (TA) is the measurement of changes in a physical property of a material that is heated through a phase transformation temperature range. The temperature changes in the material are recorded as a function of the heating or cooling time in such a manner that allows for the detection of phase transformations. In order to increase accuracy, characteristic points on the cooling curve have been identified using the first derivative curve plotted versus time. In this paper, an alternative approach to the analysis of the cooling curve has been proposed. The first derivative curve has been plotted versus temperature and all characteristic points have been identified with the same accuracy achieved using the traditional method. The new cooling curve analysis also enables the Dendrite Coherency Point (DCP) to be detected using only one thermocouple. (author)
Quantitative clinical radiobiology
International Nuclear Information System (INIS)
Bentzen, S.M.
1993-01-01
Based on a series of recent papers, a status is given of our current ability to quantify the radiobiology of human tumors and normal tissues. Progress has been made in the methods of analysis. This includes the introduction of 'direct' (maximum likelihood) analysis, incorporation of latent-time in the analyses, and statistical approaches to allow for the many factors of importance in predicting tumor-control probability of normal-tissue complications. Quantitative clinical radiobiology of normal tissues is reviewed with emphasis on fractionation sensitivity, repair kinetics, regeneration, latency, and the steepness of dose-response curves. In addition, combined modality treatment, functional endpoints, and the search for a correlation between the occurrence of different endpoints in the same individual are discussed. For tumors, quantitative analyses of fractionation sensitivity, repair kinetics, reoxygenation, and regeneration are reviewed. Other factors influencing local control are: Tumor volume, histopathologic differentiation and hemoglobin concentration. Also, the steepness of the dose-response curve for tumors is discussed. Radiobiological strategies for improving radiotherapy are discussed with emphasis on non-standard fractionation and individualization of treatment schedules. (orig.)
Watson, Roger
2015-04-01
This article describes the basic tenets of quantitative research. The concepts of dependent and independent variables are addressed and the concept of measurement and its associated issues, such as error, reliability and validity, are explored. Experiments and surveys – the principal research designs in quantitative research – are described and key features explained. The importance of the double-blind randomised controlled trial is emphasised, alongside the importance of longitudinal surveys, as opposed to cross-sectional surveys. Essential features of data storage are covered, with an emphasis on safe, anonymous storage. Finally, the article explores the analysis of quantitative data, considering what may be analysed and the main uses of statistics in analysis.
Shock, Everett L; Holland, Melanie E
2007-12-01
A framework is proposed for a quantitative approach to studying habitability. Considerations of environmental supply and organismal demand of energy lead to the conclusions that power units are most appropriate and that the units for habitability become watts per organism. Extreme and plush environments are revealed to be on a habitability continuum, and extreme environments can be quantified as those where power supply only barely exceeds demand. Strategies for laboratory and field experiments are outlined that would quantify power supplies, power demands, and habitability. An example involving a comparison of various metabolisms pursued by halophiles is shown to be well on the way to a quantitative habitability analysis.
Computational aspects of algebraic curves
Shaska, Tanush
2005-01-01
The development of new computational techniques and better computing power has made it possible to attack some classical problems of algebraic geometry. The main goal of this book is to highlight such computational techniques related to algebraic curves. The area of research in algebraic curves is receiving more interest not only from the mathematics community, but also from engineers and computer scientists, because of the importance of algebraic curves in applications including cryptography, coding theory, error-correcting codes, digital imaging, computer vision, and many more.This book cove
Melting curves of gammairradiated DNA
International Nuclear Information System (INIS)
Hofer, H.; Altmann, H.; Kehrer, M.
1978-08-01
Melting curves of gammairradiated DNA and data derived of them, are reported. The diminished stability is explained by basedestruction. DNA denatures completely at room temperature, if at least every fifth basepair is broken or weakened by irradiation. (author)
Management of the learning curve
DEFF Research Database (Denmark)
Pedersen, Peter-Christian; Slepniov, Dmitrij
2016-01-01
Purpose – This paper focuses on the management of the learning curve in overseas capacity expansions. The purpose of this paper is to unravel the direct as well as indirect influences on the learning curve and to advance the understanding of how these affect its management. Design...... the dimensions of the learning process involved in a capacity expansion project and identified the direct and indirect labour influences on the production learning curve. On this basis, the study proposes solutions to managing learning curves in overseas capacity expansions. Furthermore, the paper concludes...... with measures that have the potential to significantly reduce the non-value-added time when establishing new capacities overseas. Originality/value – The paper uses a longitudinal in-depth case study of a Danish wind turbine manufacturer and goes beyond a simplistic treatment of the lead time and learning...
Growth curves for Laron syndrome.
Laron, Z; Lilos, P; Klinger, B
1993-01-01
Growth curves for children with Laron syndrome were constructed on the basis of repeated measurements made throughout infancy, childhood, and puberty in 24 (10 boys, 14 girls) of the 41 patients with this syndrome investigated in our clinic. Growth retardation was already noted at birth, the birth length ranging from 42 to 46 cm in the 12/20 available measurements. The postnatal growth curves deviated sharply from the normal from infancy on. Both sexes showed no clear pubertal spurt. Girls co...
Flow over riblet curved surfaces
Energy Technology Data Exchange (ETDEWEB)
Loureiro, J B R; Freire, A P Silva, E-mail: atila@mecanica.ufrj.br [Mechanical Engineering Program, Federal University of Rio de Janeiro (COPPE/UFRJ), C.P. 68503, 21.941-972, Rio de Janeiro, RJ (Brazil)
2011-12-22
The present work studies the mechanics of turbulent drag reduction over curved surfaces by riblets. The effects of surface modification on flow separation over steep and smooth curved surfaces are investigated. Four types of two-dimensional surfaces are studied based on the morphometric parameters that describe the body of a blue whale. Local measurements of mean velocity and turbulence profiles are obtained through laser Doppler anemometry (LDA) and particle image velocimetry (PIV).
Intersection numbers of spectral curves
Eynard, B.
2011-01-01
We compute the symplectic invariants of an arbitrary spectral curve with only 1 branchpoint in terms of integrals of characteristic classes in the moduli space of curves. Our formula associates to any spectral curve, a characteristic class, which is determined by the laplace transform of the spectral curve. This is a hint to the key role of Laplace transform in mirror symmetry. When the spectral curve is y=\\sqrt{x}, the formula gives Kontsevich--Witten intersection numbers, when the spectral curve is chosen to be the Lambert function \\exp{x}=y\\exp{-y}, the formula gives the ELSV formula for Hurwitz numbers, and when one chooses the mirror of C^3 with framing f, i.e. \\exp{-x}=\\exp{-yf}(1-\\exp{-y}), the formula gives the Marino-Vafa formula, i.e. the generating function of Gromov-Witten invariants of C^3. In some sense this formula generalizes ELSV, Marino-Vafa formula, and Mumford formula.
International Nuclear Information System (INIS)
Haverkamp, U.; Wiezorek, C.; Poetter, R.
1990-01-01
Lyoluminescence dosimetry is based upon light emission during dissolution of previously irradiated dosimetric materials. The lyoluminescence signal is expressed in the dissolution glow curve. These curves begin, depending on the dissolution system, with a high peak followed by an exponentially decreasing intensity. System parameters that influence the graph of the dissolution glow curve, are, for example, injection speed, temperature and pH value of the solution and the design of the dissolution cell. The initial peak does not significantly correlate with the absorbed dose, it is mainly an effect of the injection. The decay of the curve consists of two exponential components: one fast and one slow. The components depend on the absorbed dose and the dosimetric materials used. In particular, the slow component correlates with the absorbed dose. In contrast to the fast component the argument of the exponential function of the slow component is independent of the dosimetric materials investigated: trehalose, glucose and mannitol. The maximum value, following the peak of the curve, and the integral light output are a measure of the absorbed dose. The reason for the different light outputs of various dosimetric materials after irradiation with the same dose is the differing solubility. The character of the dissolution glow curves is the same following irradiation with photons, electrons or neutrons. (author)
Curve Boxplot: Generalization of Boxplot for Ensembles of Curves.
Mirzargar, Mahsa; Whitaker, Ross T; Kirby, Robert M
2014-12-01
In simulation science, computational scientists often study the behavior of their simulations by repeated solutions with variations in parameters and/or boundary values or initial conditions. Through such simulation ensembles, one can try to understand or quantify the variability or uncertainty in a solution as a function of the various inputs or model assumptions. In response to a growing interest in simulation ensembles, the visualization community has developed a suite of methods for allowing users to observe and understand the properties of these ensembles in an efficient and effective manner. An important aspect of visualizing simulations is the analysis of derived features, often represented as points, surfaces, or curves. In this paper, we present a novel, nonparametric method for summarizing ensembles of 2D and 3D curves. We propose an extension of a method from descriptive statistics, data depth, to curves. We also demonstrate a set of rendering and visualization strategies for showing rank statistics of an ensemble of curves, which is a generalization of traditional whisker plots or boxplots to multidimensional curves. Results are presented for applications in neuroimaging, hurricane forecasting and fluid dynamics.
James, Jessica
2017-01-01
Quantitative finance is a field that has risen to prominence over the last few decades. It encompasses the complex models and calculations that value financial contracts, particularly those which reference events in the future, and apply probabilities to these events. While adding greatly to the flexibility of the market available to corporations and investors, it has also been blamed for worsening the impact of financial crises. But what exactly does quantitative finance encompass, and where did these ideas and models originate? We show that the mathematics behind finance and behind games of chance have tracked each other closely over the centuries and that many well-known physicists and mathematicians have contributed to the field.
Honglu, Wu; Cucinotta, F.A.; Durante, M.; Lin, Z.; Rusek, A.
2006-01-01
The space environment consists of a varying field of radiation particles including high-energy ions, with spacecraft shielding material providing the major protection to astronauts from harmful exposure. Unlike low-LET gamma or X-rays, the presence of shielding does not always reduce the radiation risks for energetic charged particle exposure. Since the dose delivered by the charged particle increases sharply as the particle approaches the end of its range, a position known as the Bragg peak, the Bragg curve does not necessarily represent the biological damage along the particle traversal since biological effects are influenced by the track structure of both primary and secondary particles. Therefore, the biological Bragg curve is dependent on the energy and the type of the primary particle, and may vary for different biological endpoints. To achieve a Bragg curve distribution, we exposed cells to energetic heavy ions with the beam geometry parallel to a monolayer of fibroblasts. Qualitative analyses of gamma-H2AX fluorescence, a known marker of DSBs, indicated increased clustering of DNA damage before the Bragg peak, enhanced homogenous distribution at the peak, and provided visual evidence of high linear energy transfer (LET) particle traversal of cells beyond the Bragg peak. A quantitative biological response curve generated for micronuclei (MN) induction across the Bragg curve did not reveal an increased yield of MN at the location of the Bragg peak. However, the ratio of mono-to bi-nucleated cells, which indicates inhibition in cell progression, increased at the Bragg peak location. These results, along with other biological concerns, show that space radiation protection with shielding can be a complicated issue.
Considerations for reference pump curves
International Nuclear Information System (INIS)
Stockton, N.B.
1992-01-01
This paper examines problems associated with inservice testing (IST) of pumps to assess their hydraulic performance using reference pump curves to establish acceptance criteria. Safety-related pumps at nuclear power plants are tested under the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (the Code), Section 11. The Code requires testing pumps at specific reference points of differential pressure or flow rate that can be readily duplicated during subsequent tests. There are many cases where test conditions cannot be duplicated. For some pumps, such as service water or component cooling pumps, the flow rate at any time depends on plant conditions and the arrangement of multiple independent and constantly changing loads. System conditions cannot be controlled to duplicate a specific reference value. In these cases, utilities frequently request to use pump curves for comparison of test data for acceptance. There is no prescribed method for developing a pump reference curve. The methods vary and may yield substantially different results. Some results are conservative when compared to the Code requirements; some are not. The errors associated with different curve testing techniques should be understood and controlled within reasonable bounds. Manufacturer's pump curves, in general, are not sufficiently accurate to use as reference pump curves for IST. Testing using reference curves generated with polynomial least squares fits over limited ranges of pump operation, cubic spline interpolation, or cubic spline least squares fits can provide a measure of pump hydraulic performance that is at least as accurate as the Code required method. Regardless of the test method, error can be reduced by using more accurate instruments, by correcting for systematic errors, by increasing the number of data points, and by taking repetitive measurements at each data point
Curve Digitizer – A software for multiple curves digitizing
Directory of Open Access Journals (Sweden)
Florentin ŞPERLEA
2010-06-01
Full Text Available The Curve Digitizer is software that extracts data from an image file representing a graphicand returns them as pairs of numbers which can then be used for further analysis and applications.Numbers can be read on a computer screen stored in files or copied on paper. The final result is adata set that can be used with other tools such as MSEXCEL. Curve Digitizer provides a useful toolfor any researcher or engineer interested in quantifying the data displayed graphically. The image filecan be obtained by scanning a document
The Cyclic Stress-Strain Curve of Polycrystals
DEFF Research Database (Denmark)
Pedersen, Ole Bøcker; Rasmussen, K. V.; Winter, A. T.
1982-01-01
The internal stresses implied by the Sachs model are estimated for individual PSBs at low plastic strain amplitudes and for homogeneously sheared grains at higher plastic strain amplitudes. The analysis shows that the Sachs model can account semi-quantitatively for experimentally measured cyclic...... stress-strain curves for copper. A similar approximative analysis of the Taylor model cannot account for the data. An interesting feature of the Sachs model is that, although it is assumed that the flow condition is entirely controlled by the PSBs. the predicted cyclic stress-strain curve displays...
The Simulation of an Oxidation-Reduction Titration Curve with Computer Algebra
Whiteley, Richard V., Jr.
2015-01-01
Although the simulation of an oxidation/reduction titration curve is an important exercise in an undergraduate course in quantitative analysis, that exercise is frequently simplified to accommodate computational limitations. With the use of readily available computer algebra systems, however, such curves for complicated systems can be generated…
Calibration curves for biological dosimetry
International Nuclear Information System (INIS)
Guerrero C, C.; Brena V, M. . E-mail cgc@nuclear.inin.mx
2004-01-01
The generated information by the investigations in different laboratories of the world, included the ININ, in which settles down that certain class of chromosomal leisure it increases in function of the dose and radiation type, has given by result the obtaining of calibrated curves that are applied in the well-known technique as biological dosimetry. In this work is presented a summary of the work made in the laboratory that includes the calibrated curves for gamma radiation of 60 Cobalt and X rays of 250 k Vp, examples of presumed exposure to ionizing radiation, resolved by means of aberration analysis and the corresponding dose estimate through the equations of the respective curves and finally a comparison among the dose calculations in those people affected by the accident of Ciudad Juarez, carried out by the group of Oak Ridge, USA and those obtained in this laboratory. (Author)
Vertex algebras and algebraic curves
Frenkel, Edward
2004-01-01
Vertex algebras are algebraic objects that encapsulate the concept of operator product expansion from two-dimensional conformal field theory. Vertex algebras are fast becoming ubiquitous in many areas of modern mathematics, with applications to representation theory, algebraic geometry, the theory of finite groups, modular functions, topology, integrable systems, and combinatorics. This book is an introduction to the theory of vertex algebras with a particular emphasis on the relationship with the geometry of algebraic curves. The notion of a vertex algebra is introduced in a coordinate-independent way, so that vertex operators become well defined on arbitrary smooth algebraic curves, possibly equipped with additional data, such as a vector bundle. Vertex algebras then appear as the algebraic objects encoding the geometric structure of various moduli spaces associated with algebraic curves. Therefore they may be used to give a geometric interpretation of various questions of representation theory. The book co...
Curve collection, extension of databases
International Nuclear Information System (INIS)
Gillemot, F.
1992-01-01
Full text: Databases: generally calculated data only. The original measurements: diagrams. Information loss between them Expensive research eg. irradiation, aging, creep etc. Original curves should be stored for reanalysing. The format of the stored curves: a. Data in ASCII files, only numbers b. Other information in strings in a second file Same name, but different extension. Extensions shows the type of the test and the type of the file. EXAMPLES. TEN is tensile information, TED is tensile data, CHN is Charpy informations, CHD is Charpy data. Storing techniques: digitalised measurements, digitalising old curves stored on paper. Use: making catalogues, reanalysing, comparison with new data. Tools: mathematical software packages like quattro, genplot, exel, mathcad, qbasic, pascal, fortran, mathlab, grapher etc. (author)
Rational points on elliptic curves
Silverman, Joseph H
2015-01-01
The theory of elliptic curves involves a pleasing blend of algebra, geometry, analysis, and number theory. This book stresses this interplay as it develops the basic theory, thereby providing an opportunity for advanced undergraduates to appreciate the unity of modern mathematics. At the same time, every effort has been made to use only methods and results commonly included in the undergraduate curriculum. This accessibility, the informal writing style, and a wealth of exercises make Rational Points on Elliptic Curves an ideal introduction for students at all levels who are interested in learning about Diophantine equations and arithmetic geometry. Most concretely, an elliptic curve is the set of zeroes of a cubic polynomial in two variables. If the polynomial has rational coefficients, then one can ask for a description of those zeroes whose coordinates are either integers or rational numbers. It is this number theoretic question that is the main subject of this book. Topics covered include the geometry and ...
Theoretical melting curve of caesium
International Nuclear Information System (INIS)
Simozar, S.; Girifalco, L.A.; Pennsylvania Univ., Philadelphia
1983-01-01
A statistical-mechanical model is developed to account for the complex melting curve of caesium. The model assumes the existence of three different species of caesium defined by three different electronic states. On the basis of this model, the free energy of melting and the melting curve are computed up to 60 kbar, using the solid-state data and the initial slope of the fusion curve as input parameters. The calculated phase diagram agrees with experiment to within the experimental error. Other thermodynamic properties including the entropy and volume of melting were also computed, and they agree with experiment. Since the theory requires only one adjustable constant, this is taken as strong evidence that the three-species model is satisfactory for caesium. (author)
DEFF Research Database (Denmark)
Brücker, Herbert; Jahn, Elke J.
in a general equilibrium framework. For the empirical analysis we employ the IABS, a two percent sample of the German labor force. We find that the elasticity of the wage curve is particularly high for young workers and workers with a university degree, while it is low for older workers and workers...... Based on a wage curve approach we examine the labor market effects of migration in Germany. The wage curve relies on the assumption that wages respond to a change in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously...... with a vocational degree. The wage and employment effects of migration are moderate: a 1 percent increase in the German labor force through immigration increases the aggregate unemployment rate by less than 0.1 percentage points and reduces average wages by less 0.1 percent. While native workers benefit from...
Laffer Curves and Home Production
Directory of Open Access Journals (Sweden)
Kotamäki Mauri
2017-06-01
Full Text Available In the earlier related literature, consumption tax rate Laffer curve is found to be strictly increasing (see Trabandt and Uhlig (2011. In this paper, a general equilibrium macro model is augmented by introducing a substitute for private consumption in the form of home production. The introduction of home production brings about an additional margin of adjustment – an increase in consumption tax rate not only decreases labor supply and reduces the consumption tax base but also allows a substitution of market goods with home-produced goods. The main objective of this paper is to show that, after the introduction of home production, the consumption tax Laffer curve exhibits an inverse U-shape. Also the income tax Laffer curves are significantly altered. The result shown in this paper casts doubt on some of the earlier results in the literature.
Complexity of Curved Glass Structures
Kosić, T.; Svetel, I.; Cekić, Z.
2017-11-01
Despite the increasing number of research on the architectural structures of curvilinear forms and technological and practical improvement of the glass production observed over recent years, there is still a lack of comprehensive codes and standards, recommendations and experience data linked to real-life curved glass structures applications regarding design, manufacture, use, performance and economy. However, more and more complex buildings and structures with the large areas of glass envelope geometrically complex shape are built every year. The aim of the presented research is to collect data on the existing design philosophy on curved glass structure cases. The investigation includes a survey about how architects and engineers deal with different design aspects of curved glass structures with a special focus on the design and construction process, glass types and structural and fixing systems. The current paper gives a brief overview of the survey findings.
Optimization on Spaces of Curves
DEFF Research Database (Denmark)
Møller-Andersen, Jakob
in Rd, and methods to solve the initial and boundary value problem for geodesics allowing us to compute the Karcher mean and principal components analysis of data of curves. We apply the methods to study shape variation in synthetic data in the Kimia shape database, in HeLa cell nuclei and cycles...... of cardiac deformations. Finally we investigate a new application of Riemannian shape analysis in shape optimization. We setup a simple elliptic model problem, and describe how to apply shape calculus to obtain directional derivatives in the manifold of planar curves. We present an implementation based...
Tracing a planar algebraic curve
International Nuclear Information System (INIS)
Chen Falai; Kozak, J.
1994-09-01
In this paper, an algorithm that determines a real algebraic curve is outlined. Its basic step is to divide the plane into subdomains that include only simple branches of the algebraic curve without singular points. Each of the branches is then stably and efficiently traced in the particular subdomain. Except for the tracing, the algorithm requires only a couple of simple operations on polynomials that can be carried out exactly if the coefficients are rational, and the determination of zeros of several polynomials of one variable. (author). 5 refs, 4 figs
The New Keynesian Phillips Curve
DEFF Research Database (Denmark)
Ólafsson, Tjörvi
This paper provides a survey on the recent literature on the new Keynesian Phillips curve: the controversies surrounding its microfoundation and estimation, the approaches that have been tried to improve its empirical fit and the challenges it faces adapting to the open-economy framework. The new......, learning or state-dependant pricing. The introduction of openeconomy factors into the new Keynesian Phillips curve complicate matters further as it must capture the nexus between price setting, inflation and the exchange rate. This is nevertheless a crucial feature for any model to be used for inflation...... forecasting in a small open economy like Iceland....
Signature Curves Statistics of DNA Supercoils
Shakiban, Cheri; Lloyd, Peter
2004-01-01
In this paper we describe the Euclidean signature curves for two dimensional closed curves in the plane and their generalization to closed space curves. The focus will be on discrete numerical methods for approximating such curves. Further we will apply these numerical methods to plot the signature curves related to three-dimensional simulated DNA supercoils. Our primary focus will be on statistical analysis of the data generated for the signature curves of the supercoils. We will try to esta...
Dual Smarandache Curves of a Timelike Curve lying on Unit dual Lorentzian Sphere
Kahraman, Tanju; Hüseyin Ugurlu, Hasan
2016-01-01
In this paper, we give Darboux approximation for dual Smarandache curves of time like curve on unit dual Lorentzian sphere. Firstly, we define the four types of dual Smarandache curves of a timelike curve lying on dual Lorentzian sphere.
Electro-Mechanical Resonance Curves
Greenslade, Thomas B., Jr.
2018-01-01
Recently I have been investigating the frequency response of galvanometers. These are direct-current devices used to measure small currents. By using a low-frequency function generator to supply the alternating-current signal and a stopwatch smartphone app to measure the period, I was able to take data to allow a resonance curve to be drawn. This…
2013-01-01
This software can be used to assist with the assessment of margin of safety for a horizontal curve. It is intended for use by engineers and technicians responsible for safety analysis or management of rural highway pavement or traffic control devices...
Principal Curves on Riemannian Manifolds.
Hauberg, Soren
2016-09-01
Euclidean statistics are often generalized to Riemannian manifolds by replacing straight-line interpolations with geodesic ones. While these Riemannian models are familiar-looking, they are restricted by the inflexibility of geodesics, and they rely on constructions which are optimal only in Euclidean domains. We consider extensions of Principal Component Analysis (PCA) to Riemannian manifolds. Classic Riemannian approaches seek a geodesic curve passing through the mean that optimizes a criteria of interest. The requirements that the solution both is geodesic and must pass through the mean tend to imply that the methods only work well when the manifold is mostly flat within the support of the generating distribution. We argue that instead of generalizing linear Euclidean models, it is more fruitful to generalize non-linear Euclidean models. Specifically, we extend the classic Principal Curves from Hastie & Stuetzle to data residing on a complete Riemannian manifold. We show that for elliptical distributions in the tangent of spaces of constant curvature, the standard principal geodesic is a principal curve. The proposed model is simple to compute and avoids many of the pitfalls of traditional geodesic approaches. We empirically demonstrate the effectiveness of the Riemannian principal curves on several manifolds and datasets.
Elliptic curves and primality proving
Atkin, A. O. L.; Morain, F.
1993-07-01
The aim of this paper is to describe the theory and implementation of the Elliptic Curve Primality Proving algorithm. Problema, numeros primos a compositis dignoscendi, hosque in factores suos primos resolvendi, ad gravissima ac utilissima totius arithmeticae pertinere, et geometrarum tum veterum tum recentiorum industriam ac sagacitatem occupavisse, tam notum est, ut de hac re copiose loqui superfluum foret.
Indian Academy of Sciences (India)
from biology, feel that every pattern in the living world, ranging from the folding of ... curves band c have the same rate of increase but reach different asymptotes. If these .... not at x = 0, but at xo' which is the minimum size at birth that will permit ...
Survival curves for irradiated cells
International Nuclear Information System (INIS)
Gibson, D.K.
1975-01-01
The subject of the lecture is the probability of survival of biological cells which have been subjected to ionising radiation. The basic mathematical theories of cell survival as a function of radiation dose are developed. A brief comparison with observed survival curves is made. (author)
Mentorship, learning curves, and balance.
Cohen, Meryl S; Jacobs, Jeffrey P; Quintessenza, James A; Chai, Paul J; Lindberg, Harald L; Dickey, Jamie; Ungerleider, Ross M
2007-09-01
Professionals working in the arena of health care face a variety of challenges as their careers evolve and develop. In this review, we analyze the role of mentorship, learning curves, and balance in overcoming challenges that all such professionals are likely to encounter. These challenges can exist both in professional and personal life. As any professional involved in health care matures, complex professional skills must be mastered, and new professional skills must be acquired. These skills are both technical and judgmental. In most circumstances, these skills must be learned. In 2007, despite the continued need for obtaining new knowledge and learning new skills, the professional and public tolerance for a "learning curve" is much less than in previous decades. Mentorship is the key to success in these endeavours. The success of mentorship is two-sided, with responsibilities for both the mentor and the mentee. The benefits of this relationship must be bidirectional. It is the responsibility of both the student and the mentor to assure this bidirectional exchange of benefit. This relationship requires time, patience, dedication, and to some degree selflessness. This mentorship will ultimately be the best tool for mastering complex professional skills and maturing through various learning curves. Professional mentorship also requires that mentors identify and explicitly teach their mentees the relational skills and abilities inherent in learning the management of the triad of self, relationships with others, and professional responsibilities.Up to two decades ago, a learning curve was tolerated, and even expected, while professionals involved in healthcare developed the techniques that allowed for the treatment of previously untreatable diseases. Outcomes have now improved to the point that this type of learning curve is no longer acceptable to the public. Still, professionals must learn to perform and develop independence and confidence. The responsibility to
International Nuclear Information System (INIS)
Brase, J.M.; Martz, H.E.; Waltjen, K.E.; Hurd, R.L.; Wieting, M.G.
1986-01-01
Radiographic techniques have been used in nondestructive evaluation primarily to develop qualitative information (i.e., defect detection). This project applies and extends the techniques developed in medical x-ray imaging, particularly computed tomography (CT), to develop quantitative information (both spatial dimensions and material quantities) on the three-dimensional (3D) structure of solids. Accomplishments in FY 86 include (1) improvements in experimental equipment - an improved microfocus system that will give 20-μm resolution and has potential for increased imaging speed, and (2) development of a simple new technique for displaying 3D images so as to clearly show the structure of the object. Image reconstruction and data analysis for a series of synchrotron CT experiments conducted by LLNL's Chemistry Department has begun
A catalog of special plane curves
Lawrence, J Dennis
2014-01-01
Among the largest, finest collections available-illustrated not only once for each curve, but also for various values of any parameters present. Covers general properties of curves and types of derived curves. Curves illustrated by a CalComp digital incremental plotter. 12 illustrations.
Computation of undulator tuning curves
International Nuclear Information System (INIS)
Dejus, Roger J.
1997-01-01
Computer codes for fast computation of on-axis brilliance tuning curves and flux tuning curves have been developed. They are valid for an ideal device (regular planar device or a helical device) using the Bessel function formalism. The effects of the particle beam emittance and the beam energy spread on the spectrum are taken into account. The applicability of the codes and the importance of magnetic field errors of real insertion devices are addressed. The validity of the codes has been experimentally verified at the APS and observed discrepancies are in agreement with predicted reduction of intensities due to magnetic field errors. The codes are distributed as part of the graphical user interface XOP (X-ray OPtics utilities), which simplifies execution and viewing of the results
Curved canals: Ancestral files revisited
Directory of Open Access Journals (Sweden)
Jain Nidhi
2008-01-01
Full Text Available The aim of this article is to provide an insight into different techniques of cleaning and shaping of curved root canals with hand instruments. Although a plethora of root canal instruments like ProFile, ProTaper, LightSpeed ® etc dominate the current scenario, the inexpensive conventional root canal hand files such as K-files and flexible files can be used to get optimum results when handled meticulously. Special emphasis has been put on the modifications in biomechanical canal preparation in a variety of curved canal cases. This article compiles a series of clinical cases of root canals with curvatures in the middle and apical third and with S-shaped curvatures that were successfully completed by employing only conventional root canal hand instruments.
Invariance for Single Curved Manifold
Castro, Pedro Machado Manhaes de
2012-01-01
Recently, it has been shown that, for Lambert illumination model, solely scenes composed by developable objects with a very particular albedo distribution produce an (2D) image with isolines that are (almost) invariant to light direction change. In this work, we provide and investigate a more general framework, and we show that, in general, the requirement for such in variances is quite strong, and is related to the differential geometry of the objects. More precisely, it is proved that single curved manifolds, i.e., manifolds such that at each point there is at most one principal curvature direction, produce invariant is surfaces for a certain relevant family of energy functions. In the three-dimensional case, the associated energy function corresponds to the classical Lambert illumination model with albedo. This result is also extended for finite-dimensional scenes composed by single curved objects. © 2012 IEEE.
Invariance for Single Curved Manifold
Castro, Pedro Machado Manhaes de
2012-08-01
Recently, it has been shown that, for Lambert illumination model, solely scenes composed by developable objects with a very particular albedo distribution produce an (2D) image with isolines that are (almost) invariant to light direction change. In this work, we provide and investigate a more general framework, and we show that, in general, the requirement for such in variances is quite strong, and is related to the differential geometry of the objects. More precisely, it is proved that single curved manifolds, i.e., manifolds such that at each point there is at most one principal curvature direction, produce invariant is surfaces for a certain relevant family of energy functions. In the three-dimensional case, the associated energy function corresponds to the classical Lambert illumination model with albedo. This result is also extended for finite-dimensional scenes composed by single curved objects. © 2012 IEEE.
Curved Folded Plate Timber Structures
Buri, Hans Ulrich; Stotz, Ivo; Weinand, Yves
2011-01-01
This work investigates the development of a Curved Origami Prototype made with timber panels. In the last fifteen years the timber industry has developed new, large size, timber panels. Composition and dimensions of these panels and the possibility of milling them with Computer Numerical Controlled machines shows great potential for folded plate structures. To generate the form of these structures we were inspired by Origami, the Japanese art of paper folding. Common paper tessellations are c...
Projection-based curve clustering
International Nuclear Information System (INIS)
Auder, Benjamin; Fischer, Aurelie
2012-01-01
This paper focuses on unsupervised curve classification in the context of nuclear industry. At the Commissariat a l'Energie Atomique (CEA), Cadarache (France), the thermal-hydraulic computer code CATHARE is used to study the reliability of reactor vessels. The code inputs are physical parameters and the outputs are time evolution curves of a few other physical quantities. As the CATHARE code is quite complex and CPU time-consuming, it has to be approximated by a regression model. This regression process involves a clustering step. In the present paper, the CATHARE output curves are clustered using a k-means scheme, with a projection onto a lower dimensional space. We study the properties of the empirically optimal cluster centres found by the clustering method based on projections, compared with the 'true' ones. The choice of the projection basis is discussed, and an algorithm is implemented to select the best projection basis among a library of orthonormal bases. The approach is illustrated on a simulated example and then applied to the industrial problem. (authors)
Growth curves for Laron syndrome.
Laron, Z; Lilos, P; Klinger, B
1993-01-01
Growth curves for children with Laron syndrome were constructed on the basis of repeated measurements made throughout infancy, childhood, and puberty in 24 (10 boys, 14 girls) of the 41 patients with this syndrome investigated in our clinic. Growth retardation was already noted at birth, the birth length ranging from 42 to 46 cm in the 12/20 available measurements. The postnatal growth curves deviated sharply from the normal from infancy on. Both sexes showed no clear pubertal spurt. Girls completed their growth between the age of 16-19 years to a final mean (SD) height of 119 (8.5) cm whereas the boys continued growing beyond the age of 20 years, achieving a final height of 124 (8.5) cm. At all ages the upper to lower body segment ratio was more than 2 SD above the normal mean. These growth curves constitute a model not only for primary, hereditary insulin-like growth factor-I (IGF-I) deficiency (Laron syndrome) but also for untreated secondary IGF-I deficiencies such as growth hormone gene deletion and idiopathic congenital isolated growth hormone deficiency. They should also be useful in the follow up of children with Laron syndrome treated with biosynthetic recombinant IGF-I. PMID:8333769
Elementary particles in curved spaces
International Nuclear Information System (INIS)
Lazanu, I.
2004-01-01
The theories in particle physics are developed currently, in Minkowski space-time starting from the Poincare group. A physical theory in flat space can be seen as the limit of a more general physical theory in a curved space. At the present time, a theory of particles in curved space does not exist, and thus the only possibility is to extend the existent theories in these spaces. A formidable obstacle to the extension of physical models is the absence of groups of motion in more general Riemann spaces. A space of constant curvature has a group of motion that, although differs from that of a flat space, has the same number of parameters and could permit some generalisations. In this contribution we try to investigate some physical implications of the presumable existence of elementary particles in curved space. In de Sitter space (dS) the invariant rest mass is a combination of the Poincare rest mass and the generalised angular momentum of a particle and it permits to establish a correlation with the vacuum energy and with the cosmological constant. The consequences are significant because in an experiment the local structure of space-time departs from the Minkowski space and becomes a dS or AdS space-time. Discrete symmetry characteristics of the dS/AdS group suggest some arguments for the possible existence of the 'mirror matter'. (author)
Braun, Jean; van der Beek, Peter; Batt, Geoffrey
2006-05-01
Thermochronology, the study of the thermal history of rocks, enables us to quantify the nature and timing of tectonic processes. Quantitative Thermochronology is a robust review of isotopic ages, and presents a range of numerical modeling techniques to allow the physical implications of isotopic age data to be explored. The authors provide analytical, semi-analytical, and numerical solutions to the heat transfer equation in a range of tectonic settings and under varying boundary conditions. They then illustrate their modeling approach built around a large number of case studies. The benefits of different thermochronological techniques are also described. Computer programs on an accompanying website at www.cambridge.org/9780521830577 are introduced through the text and provide a means of solving the heat transport equation in the deforming Earth to predict the ages of rocks and compare them directly to geological and geochronological data. Several short tutorials, with hints and solutions, are also included. Numerous case studies help geologists to interpret age data and relate it to Earth processes Essential background material to aid understanding and using thermochronological data Provides a thorough treatise on numerical modeling of heat transport in the Earth's crust Supported by a website hosting relevant computer programs and colour slides of figures from the book for use in teaching
Dual Smarandache Curves and Smarandache Ruled Surfaces
Tanju KAHRAMAN; Mehmet ÖNDER; H. Hüseyin UGURLU
2013-01-01
In this paper, by considering dual geodesic trihedron (dual Darboux frame) we define dual Smarandache curves lying fully on dual unit sphere S^2 and corresponding to ruled surfaces. We obtain the relationships between the elements of curvature of dual spherical curve (ruled surface) x(s) and its dual Smarandache curve (Smarandache ruled surface) x1(s) and we give an example for dual Smarandache curves of a dual spherical curve.
High Performance Liquid Chromatography of Vitamin A: A Quantitative Determination.
Bohman, Ove; And Others
1982-01-01
Experimental procedures are provided for the quantitative determination of Vitamin A (retinol) in food products by analytical liquid chromatography. Standard addition and calibration curve extraction methods are outlined. (SK)
The quantitative Morse theorem
Loi, Ta Le; Phien, Phan
2013-01-01
In this paper, we give a proof of the quantitative Morse theorem stated by {Y. Yomdin} in \\cite{Y1}. The proof is based on the quantitative Sard theorem, the quantitative inverse function theorem and the quantitative Morse lemma.
Observable Zitterbewegung in curved spacetimes
Kobakhidze, Archil; Manning, Adrian; Tureanu, Anca
2016-06-01
Zitterbewegung, as it was originally described by Schrödinger, is an unphysical, non-observable effect. We verify whether the effect can be observed in non-inertial reference frames/curved spacetimes, where the ambiguity in defining particle states results in a mixing of positive and negative frequency modes. We explicitly demonstrate that such a mixing is in fact necessary to obtain the correct classical value for a particle's velocity in a uniformly accelerated reference frame, whereas in cosmological spacetime a particle does indeed exhibit Zitterbewegung.
Observable Zitterbewegung in curved spacetimes
Energy Technology Data Exchange (ETDEWEB)
Kobakhidze, Archil, E-mail: archilk@physics.usyd.edu.au [ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, The University of Sydney, NSW 2006 (Australia); Manning, Adrian, E-mail: a.manning@physics.usyd.edu.au [ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, The University of Sydney, NSW 2006 (Australia); Tureanu, Anca, E-mail: anca.tureanu@helsinki.fi [Department of Physics, University of Helsinki, P.O. Box 64, 00014 Helsinki (Finland)
2016-06-10
Zitterbewegung, as it was originally described by Schrödinger, is an unphysical, non-observable effect. We verify whether the effect can be observed in non-inertial reference frames/curved spacetimes, where the ambiguity in defining particle states results in a mixing of positive and negative frequency modes. We explicitly demonstrate that such a mixing is in fact necessary to obtain the correct classical value for a particle's velocity in a uniformly accelerated reference frame, whereas in cosmological spacetime a particle does indeed exhibit Zitterbewegung.
Differential geometry curves, surfaces, manifolds
Kohnel, Wolfgang
2002-01-01
This carefully written book is an introduction to the beautiful ideas and results of differential geometry. The first half covers the geometry of curves and surfaces, which provide much of the motivation and intuition for the general theory. Special topics that are explored include Frenet frames, ruled surfaces, minimal surfaces and the Gauss-Bonnet theorem. The second part is an introduction to the geometry of general manifolds, with particular emphasis on connections and curvature. The final two chapters are insightful examinations of the special cases of spaces of constant curvature and Einstein manifolds. The text is illustrated with many figures and examples. The prerequisites are undergraduate analysis and linear algebra.
LINS Curve in Romanian Economy
Directory of Open Access Journals (Sweden)
Emilian Dobrescu
2016-02-01
Full Text Available The paper presents theoretical considerations and empirical evidence to test the validity of the Laffer in Narrower Sense (LINS curve as a parabola with a maximum. Attention is focused on the so-called legal-effective tax gap (letg. The econometric application is based on statistical data (1990-2013 for Romania as an emerging European economy. Three cointegrating regressions (fully modified least squares, canonical cointegrating regression and dynamic least squares and three algorithms, which are based on instrumental variables (two-stage least squares, generalized method of moments, and limited information maximum likelihood, are involved.
Differential geometry and topology of curves
Animov, Yu
2001-01-01
Differential geometry is an actively developing area of modern mathematics. This volume presents a classical approach to the general topics of the geometry of curves, including the theory of curves in n-dimensional Euclidean space. The author investigates problems for special classes of curves and gives the working method used to obtain the conditions for closed polygonal curves. The proof of the Bakel-Werner theorem in conditions of boundedness for curves with periodic curvature and torsion is also presented. This volume also highlights the contributions made by great geometers. past and present, to differential geometry and the topology of curves.
Flow characteristics of curved ducts
Directory of Open Access Journals (Sweden)
Rudolf P.
2007-10-01
Full Text Available Curved channels are very often present in real hydraulic systems, e.g. curved diffusers of hydraulic turbines, S-shaped bulb turbines, fittings, etc. Curvature brings change of velocity profile, generation of vortices and production of hydraulic losses. Flow simulation using CFD techniques were performed to understand these phenomena. Cases ranging from single elbow to coupled elbows in shapes of U, S and spatial right angle position with circular cross-section were modeled for Re = 60000. Spatial development of the flow was studied and consequently it was deduced that minor losses are connected with the transformation of pressure energy into kinetic energy and vice versa. This transformation is a dissipative process and is reflected in the amount of the energy irreversibly lost. Least loss coefficient is connected with flow in U-shape elbows, biggest one with flow in Sshape elbows. Finally, the extent of the flow domain influenced by presence of curvature was examined. This isimportant for proper placement of mano- and flowmeters during experimental tests. Simulations were verified with experimental results presented in literature.
Improved capacitive melting curve measurements
International Nuclear Information System (INIS)
Sebedash, Alexander; Tuoriniemi, Juha; Pentti, Elias; Salmela, Anssi
2009-01-01
Sensitivity of the capacitive method for determining the melting pressure of helium can be enhanced by loading the empty side of the capacitor with helium at a pressure nearly equal to that desired to be measured and by using a relatively thin and flexible membrane in between. This way one can achieve a nanobar resolution at the level of 30 bar, which is two orders of magnitude better than that of the best gauges with vacuum reference. This extends the applicability of melting curve thermometry to lower temperatures and would allow detecting tiny anomalies in the melting pressure, which must be associated with any phenomena contributing to the entropy of the liquid or solid phases. We demonstrated this principle in measurements of the crystallization pressure of isotopic helium mixtures at millikelvin temperatures by using partly solid pure 4 He as the reference substance providing the best possible universal reference pressure. The achieved sensitivity was good enough for melting curve thermometry on mixtures down to 100 μK. Similar system can be used on pure isotopes by virtue of a blocked capillary giving a stable reference condition with liquid slightly below the melting pressure in the reference volume. This was tested with pure 4 He at temperatures 0.08-0.3 K. To avoid spurious heating effects, one must carefully choose and arrange any dielectric materials close to the active capacitor. We observed some 100 pW loading at moderate excitation voltages.
Classical optics and curved spaces
International Nuclear Information System (INIS)
Bailyn, M.; Ragusa, S.
1976-01-01
In the eikonal approximation of classical optics, the unit polarization 3-vector of light satisfies an equation that depends only on the index, n, of refraction. It is known that if the original 3-space line element is d sigma 2 , then this polarization direction propagates parallely in the fictitious space n 2 d sigma 2 . Since the equation depends only on n, it is possible to invent a fictitious curved 4-space in which the light performs a null geodesic, and the polarization 3-vector behaves as the 'shadow' of a parallely propagated 4-vector. The inverse, namely, the reduction of Maxwell's equation, on a curve 'dielectric free) space, to a classical space with dielectric constant n=(-g 00 ) -1 / 2 is well known, but in the latter the dielectric constant epsilon and permeability μ must also equal (-g 00 ) -1 / 2 . The rotation of polarization as light bends around the sun by utilizing the reduction to the classical space, is calculated. This (non-) rotation may then be interpreted as parallel transport in the 3-space n 2 d sigma 2 [pt
2002-01-01
The Atlas of Stress-Strain Curves, Second Edition is substantially bigger in page dimensions, number of pages, and total number of curves than the previous edition. It contains over 1,400 curves, almost three times as many as in the 1987 edition. The curves are normalized in appearance to aid making comparisons among materials. All diagrams include metric (SI) units, and many also include U.S. customary units. All curves are captioned in a consistent format with valuable information including (as available) standard designation, the primary source of the curve, mechanical properties (including hardening exponent and strength coefficient), condition of sample, strain rate, test temperature, and alloy composition. Curve types include monotonic and cyclic stress-strain, isochronous stress-strain, and tangent modulus. Curves are logically arranged and indexed for fast retrieval of information. The book also includes an introduction that provides background information on methods of stress-strain determination, on...
Transition curves for highway geometric design
Kobryń, Andrzej
2017-01-01
This book provides concise descriptions of the various solutions of transition curves, which can be used in geometric design of roads and highways. It presents mathematical methods and curvature functions for defining transition curves. .
Comparison and evaluation of mathematical lactation curve ...
African Journals Online (AJOL)
p2492989
A mathematical model of the lactation curve provides summary information about culling and milking strategies ..... Table 2 Statistics of the edited data for first lactation Holstein cows ..... Application of different models to the lactation curves of.
Chong, Bin; Yu, Dongliang; Jin, Rong; Wang, Yang; Li, Dongdong; Song, Ye; Gao, Mingqi; Zhu, Xufei
2015-04-01
Anodic TiO2 nanotubes have been studied extensively for many years. However, the growth kinetics still remains unclear. The systematic study of the current transient under constant anodizing voltage has not been mentioned in the original literature. Here, a derivation and its corresponding theoretical formula are proposed to overcome this challenge. In this paper, the theoretical expressions for the time dependent ionic current and electronic current are derived to explore the anodizing process of Ti. The anodizing current-time curves under different anodizing voltages and different temperatures are experimentally investigated in the anodization of Ti. Furthermore, the quantitative relationship between the thickness of the barrier layer and anodizing time, and the relationships between the ionic/electronic current and temperatures are proposed in this paper. All of the current-transient plots can be fitted consistently by the proposed theoretical expressions. Additionally, it is the first time that the coefficient A of the exponential relationship (ionic current jion = A exp(BE)) has been determined under various temperatures and voltages. And the results indicate that as temperature and voltage increase, ionic current and electronic current both increase. The temperature has a larger effect on electronic current than ionic current. These results can promote the research of kinetics from a qualitative to quantitative level.
Chong, Bin; Yu, Dongliang; Jin, Rong; Wang, Yang; Li, Dongdong; Song, Ye; Gao, Mingqi; Zhu, Xufei
2015-04-10
Anodic TiO2 nanotubes have been studied extensively for many years. However, the growth kinetics still remains unclear. The systematic study of the current transient under constant anodizing voltage has not been mentioned in the original literature. Here, a derivation and its corresponding theoretical formula are proposed to overcome this challenge. In this paper, the theoretical expressions for the time dependent ionic current and electronic current are derived to explore the anodizing process of Ti. The anodizing current-time curves under different anodizing voltages and different temperatures are experimentally investigated in the anodization of Ti. Furthermore, the quantitative relationship between the thickness of the barrier layer and anodizing time, and the relationships between the ionic/electronic current and temperatures are proposed in this paper. All of the current-transient plots can be fitted consistently by the proposed theoretical expressions. Additionally, it is the first time that the coefficient A of the exponential relationship (ionic current j(ion) = A exp(BE)) has been determined under various temperatures and voltages. And the results indicate that as temperature and voltage increase, ionic current and electronic current both increase. The temperature has a larger effect on electronic current than ionic current. These results can promote the research of kinetics from a qualitative to quantitative level.
Ait-Haddou, Rachid; Sakane, Yusuke; Nomura, Taishin
2013-01-01
We show that the generalized Bernstein bases in Müntz spaces defined by Hirschman and Widder (1949) and extended by Gelfond (1950) can be obtained as pointwise limits of the Chebyshev–Bernstein bases in Müntz spaces with respect to an interval [a,1][a,1] as the positive real number a converges to zero. Such a realization allows for concepts of curve design such as de Casteljau algorithm, blossom, dimension elevation to be transferred from the general theory of Chebyshev blossoms in Müntz spaces to these generalized Bernstein bases that we termed here as Gelfond–Bernstein bases. The advantage of working with Gelfond–Bernstein bases lies in the simplicity of the obtained concepts and algorithms as compared to their Chebyshev–Bernstein bases counterparts.
Bubble Collision in Curved Spacetime
International Nuclear Information System (INIS)
Hwang, Dong-il; Lee, Bum-Hoon; Lee, Wonwoo; Yeom, Dong-han
2014-01-01
We study vacuum bubble collisions in curved spacetime, in which vacuum bubbles were nucleated in the initial metastable vacuum state by quantum tunneling. The bubbles materialize randomly at different times and then start to grow. It is known that the percolation by true vacuum bubbles is not possible due to the exponential expansion of the space among the bubbles. In this paper, we consider two bubbles of the same size with a preferred axis and assume that two bubbles form very near each other to collide. The two bubbles have the same field value. When the bubbles collide, the collided region oscillates back-and-forth and then the collided region eventually decays and disappears. We discuss radiation and gravitational wave resulting from the collision of two bubbles
Bacterial streamers in curved microchannels
Rusconi, Roberto; Lecuyer, Sigolene; Guglielmini, Laura; Stone, Howard
2009-11-01
Biofilms, generally identified as microbial communities embedded in a self-produced matrix of extracellular polymeric substances, are involved in a wide variety of health-related problems ranging from implant-associated infections to disease transmissions and dental plaque. The usual picture of these bacterial films is that they grow and develop on surfaces. However, suspended biofilm structures, or streamers, have been found in natural environments (e.g., rivers, acid mines, hydrothermal hot springs) and are always suggested to stem from a turbulent flow. We report the formation of bacterial streamers in curved microfluidic channels. By using confocal laser microscopy we are able to directly image and characterize the spatial and temporal evolution of these filamentous structures. Such streamers, which always connect the inner corners of opposite sides of the channel, are always located in the middle plane. Numerical simulations of the flow provide evidences for an underlying hydrodynamic mechanism behind the formation of the streamers.
Ait-Haddou, Rachid
2013-02-01
We show that the generalized Bernstein bases in Müntz spaces defined by Hirschman and Widder (1949) and extended by Gelfond (1950) can be obtained as pointwise limits of the Chebyshev–Bernstein bases in Müntz spaces with respect to an interval [a,1][a,1] as the positive real number a converges to zero. Such a realization allows for concepts of curve design such as de Casteljau algorithm, blossom, dimension elevation to be transferred from the general theory of Chebyshev blossoms in Müntz spaces to these generalized Bernstein bases that we termed here as Gelfond–Bernstein bases. The advantage of working with Gelfond–Bernstein bases lies in the simplicity of the obtained concepts and algorithms as compared to their Chebyshev–Bernstein bases counterparts.
Sibling curves of quadratic polynomials | Wiggins | Quaestiones ...
African Journals Online (AJOL)
Sibling curves were demonstrated in [1, 2] as a novel way to visualize the zeroes of real valued functions. In [3] it was shown that a polynomial of degree n has n sibling curves. This paper focuses on the algebraic and geometric properites of the sibling curves of real and complex quadratic polynomials. Key words: Quadratic ...
GLOBAL AND STRICT CURVE FITTING METHOD
Nakajima, Y.; Mori, S.
2004-01-01
To find a global and smooth curve fitting, cubic BSpline method and gathering line methods are investigated. When segmenting and recognizing a contour curve of character shape, some global method is required. If we want to connect contour curves around a singular point like crossing points,
Trigonometric Characterization of Some Plane Curves
Indian Academy of Sciences (India)
IAS Admin
(Figure 1). A relation between tan θ and tanψ gives the trigonometric equation of the family of curves. In this article, trigonometric equations of some known plane curves are deduced and it is shown that these equations reveal some geometric characteristics of the families of the curves under consideration. In Section 2,.
M-curves and symmetric products
Indian Academy of Sciences (India)
Indranil Biswas
2017-08-03
Aug 3, 2017 ... is bounded above by g + 1, where g is the genus of X [11]. Curves which have exactly the maximum number (i.e., genus +1) of components of the real part are called M-curves. Classifying real algebraic curves up to homeomorphism is straightforward, however, classifying even planar non-singular real ...
Holomorphic curves in exploded manifolds: Kuranishi structure
Parker, Brett
2013-01-01
This paper constructs a Kuranishi structure for the moduli stack of holomorphic curves in exploded manifolds. To avoid some technicalities of abstract Kuranishi structures, we embed our Kuranishi structure inside a moduli stack of curves. The construction also works for the moduli stack of holomorphic curves in any compact symplectic manifold.
Automated Blazar Light Curves Using Machine Learning
Energy Technology Data Exchange (ETDEWEB)
Johnson, Spencer James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-07-27
This presentation describes a problem and methodology pertaining to automated blazar light curves. Namely, optical variability patterns for blazars require the construction of light curves and in order to generate the light curves, data must be filtered before processing to ensure quality.
Method of construction spatial transition curve
Directory of Open Access Journals (Sweden)
S.V. Didanov
2013-04-01
Full Text Available Purpose. The movement of rail transport (speed rolling stock, traffic safety, etc. is largely dependent on the quality of the track. In this case, a special role is the transition curve, which ensures smooth insertion of the transition from linear to circular section of road. The article deals with modeling of spatial transition curve based on the parabolic distribution of the curvature and torsion. This is a continuation of research conducted by the authors regarding the spatial modeling of curved contours. Methodology. Construction of the spatial transition curve is numerical methods for solving nonlinear integral equations, where the initial data are taken coordinate the starting and ending points of the curve of the future, and the inclination of the tangent and the deviation of the curve from the tangent plane at these points. System solutions for the numerical method are the partial derivatives of the equations of the unknown parameters of the law of change of torsion and length of the transition curve. Findings. The parametric equations of the spatial transition curve are calculated by finding the unknown coefficients of the parabolic distribution of the curvature and torsion, as well as the spatial length of the transition curve. Originality. A method for constructing the spatial transition curve is devised, and based on this software geometric modeling spatial transition curves of railway track with specified deviations of the curve from the tangent plane. Practical value. The resulting curve can be applied in any sector of the economy, where it is necessary to ensure a smooth transition from linear to circular section of the curved space bypass. An example is the transition curve in the construction of the railway line, road, pipe, profile, flat section of the working blades of the turbine and compressor, the ship, plane, car, etc.
PMAnalyzer: a new web interface for bacterial growth curve analysis.
Cuevas, Daniel A; Edwards, Robert A
2017-06-15
Bacterial growth curves are essential representations for characterizing bacteria metabolism within a variety of media compositions. Using high-throughput, spectrophotometers capable of processing tens of 96-well plates, quantitative phenotypic information can be easily integrated into the current data structures that describe a bacterial organism. The PMAnalyzer pipeline performs a growth curve analysis to parameterize the unique features occurring within microtiter wells containing specific growth media sources. We have expanded the pipeline capabilities and provide a user-friendly, online implementation of this automated pipeline. PMAnalyzer version 2.0 provides fast automatic growth curve parameter analysis, growth identification and high resolution figures of sample-replicate growth curves and several statistical analyses. PMAnalyzer v2.0 can be found at https://edwards.sdsu.edu/pmanalyzer/ . Source code for the pipeline can be found on GitHub at https://github.com/dacuevas/PMAnalyzer . Source code for the online implementation can be found on GitHub at https://github.com/dacuevas/PMAnalyzerWeb . dcuevas08@gmail.com. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press.
Application of Learning Curves for Didactic Model Evaluation: Case Studies
Directory of Open Access Journals (Sweden)
Felix Mödritscher
2013-01-01
Full Text Available The success of (online courses depends, among other factors, on the underlying didactical models which have always been evaluated with qualitative and quantitative research methods. Several new evaluation techniques have been developed and established in the last years. One of them is ‘learning curves’, which aim at measuring error rates of users when they interact with adaptive educational systems, thereby enabling the underlying models to be evaluated and improved. In this paper, we report how we have applied this new method to two case studies to show that learning curves are useful to evaluate didactical models and their implementation in educational platforms. Results show that the error rates follow a power law distribution with each additional attempt if the didactical model of an instructional unit is valid. Furthermore, the initial error rate, the slope of the curve and the goodness of fit of the curve are valid indicators for the difficulty level of a course and the quality of its didactical model. As a conclusion, the idea of applying learning curves for evaluating didactical model on the basis of usage data is considered to be valuable for supporting teachers and learning content providers in improving their online courses.
Power forward curves: a managerial perspective
International Nuclear Information System (INIS)
Nagarajan, Shankar
1999-01-01
This chapter concentrates on managerial application of power forward curves, and examines the determinants of electricity prices such as transmission constraints, its inability to be stored in a conventional way, its seasonality and weather dependence, the generation stack, and the swing risk. The electricity forward curve, classical arbitrage, constructing a forward curve, volatilities, and electricity forward curve models such as the jump-diffusion model, the mean-reverting heteroscedastic volatility model, and an econometric model of forward prices are examined. A managerial perspective of the applications of the forward curve is presented covering plant valuation, capital budgeting, performance measurement, product pricing and structuring, asset optimisation, valuation of transmission options, and risk management
Retrograde curves of solidus and solubility
International Nuclear Information System (INIS)
Vasil'ev, M.V.
1979-01-01
The investigation was concerned with the constitutional diagrams of the eutectic type with ''retrograde solidus'' and ''retrograde solubility curve'' which must be considered as diagrams with degenerate monotectic transformation. The solidus and the solubility curves form a retrograde curve with a common retrograde point representing the solubility maximum. The two branches of the Aetrograde curve can be described with the aid of two similar equations. Presented are corresponding equations for the Cd-Zn system and shown is the possibility of predicting the run of the solubility curve
The writhe of open and closed curves
International Nuclear Information System (INIS)
Berger, Mitchell A; Prior, Chris
2006-01-01
Twist and writhe measure basic geometric properties of a ribbon or tube. While these measures have applications in molecular biology, materials science, fluid mechanics and astrophysics, they are under-utilized because they are often considered difficult to compute. In addition, many applications involve curves with endpoints (open curves); but for these curves the definition of writhe can be ambiguous. This paper provides simple expressions for the writhe of closed curves, and provides a new definition of writhe for open curves. The open curve definition is especially appropriate when the curve is anchored at endpoints on a plane or stretches between two parallel planes. This definition can be especially useful for magnetic flux tubes in the solar atmosphere, and for isotropic rods with ends fixed to a plane
Path integrals on curved manifolds
International Nuclear Information System (INIS)
Grosche, C.; Steiner, F.
1987-01-01
A general framework for treating path integrals on curved manifolds is presented. We also show how to perform general coordinate and space-time transformations in path integrals. The main result is that one has to subtract a quantum correction ΔV ∝ ℎ 2 from the classical Lagrangian L, i.e. the correct effective Lagrangian to be used in the path integral is L eff = L-ΔV. A general prescription for calculating the quantum correction ΔV is given. It is based on a canonical approach using Weyl-ordering and the Hamiltonian path integral defined by the midpoint prescription. The general framework is illustrated by several examples: The d-dimensional rotator, i.e. the motion on the sphere S d-1 , the path integral in d-dimensional polar coordinates, the exact treatment of the hydrogen atom in R 2 and R 3 by performing a Kustaanheimo-Stiefel transformation, the Langer transformation and the path integral for the Morse potential. (orig.)
Page curves for tripartite systems
International Nuclear Information System (INIS)
Hwang, Junha; Lee, Deok Sang; Nho, Dongju; Oh, Jeonghun; Park, Hyosub; Zoe, Heeseung; Yeom, Dong-han
2017-01-01
We investigate information flow and Page curves for tripartite systems. We prepare a tripartite system (say, A , B , and C ) of a given number of states and calculate information and entropy contents by assuming random states. Initially, every particle was in A (this means a black hole), and as time goes on, particles move to either B (this means Hawking radiation) or C (this means a broadly defined remnant, including a non-local transport of information, the last burst, an interior large volume, or a bubble universe, etc). If the final number of states of the remnant is smaller than that of Hawking radiation, then information will be stored by both the radiation and the mutual information between the radiation and the remnant, while the remnant itself does not contain information. On the other hand, if the final number of states of the remnant is greater than that of Hawking radiation, then the radiation contains negligible information, while the remnant and the mutual information between the radiation and the remnant contain information. Unless the number of states of the remnant is large enough compared to the entropy of the black hole, Hawking radiation must contain information; and we meet the menace of black hole complementarity again. Therefore, this contrasts the tension between various assumptions and candidates of the resolution of the information loss problem. (paper)
Vacuum polarization in curved spacetime
International Nuclear Information System (INIS)
Guy, R.W.
1979-01-01
A necessary step in the process of understanding the quantum theory of gravity is the calculation of the stress-energy tensor of quantized fields in curved space-times. The determination of the stress tensor, a formally divergent object, is made possible in this dissertation by utilizing the zeta-function method of regularization and renormalization. By employing this scheme's representation of the renormalized effective action functional, an expression of the stress tensor for a massless, conformally invariant scalar field, first given by DeWitt, is derived. The form of the renormalized stress tensor is first tested in various examples of flat space-times. It is shown to vanish in Minkowski space and to yield the accepted value of the energy density in the Casimir effect. Next, the stress tensor is calculated in two space-times of constant curvature, the Einstein universe and the deSitter universe, and the results are shown to agree with those given by an expression of the stress tensor that is valid in conformally flat space-times. This work culminates in the determination of the stress tensor on the horizon of a Schwarzschild black hole. This is accomplished by approximating the radial part of the eigen-functions and the metric in the vicinity of the horizon. The stress tensor at this level approximation is found to be pure trace. The approximated forms of the Schwarzschild metric describes a conformally flat space-time that possesses horizons
Stronger misdirection in curved than in straight motion
Directory of Open Access Journals (Sweden)
Jorge eOtero-Millan
2011-11-01
Full Text Available Illusions developed by magicians are a rich and largely untapped source of insight into perception and cognition. Here we show that curved motion, as employed by the magician in a classic sleight of hand trick, generates stronger misdirection than rectilinear motion, and that this difference can be explained by the differential engagement of the smooth pursuit and the saccadic oculomotor systems. This research moreover exemplifies how the magician’s intuitive understanding of the spectator’s mindset can surpass that of the cognitive scientist in specific instances, and that observation-based behavioral insights developed by magicians are worthy of quantitative investigation in the neuroscience laboratory.
Consistent Valuation across Curves Using Pricing Kernels
Directory of Open Access Journals (Sweden)
Andrea Macrina
2018-03-01
Full Text Available The general problem of asset pricing when the discount rate differs from the rate at which an asset’s cash flows accrue is considered. A pricing kernel framework is used to model an economy that is segmented into distinct markets, each identified by a yield curve having its own market, credit and liquidity risk characteristics. The proposed framework precludes arbitrage within each market, while the definition of a curve-conversion factor process links all markets in a consistent arbitrage-free manner. A pricing formula is then derived, referred to as the across-curve pricing formula, which enables consistent valuation and hedging of financial instruments across curves (and markets. As a natural application, a consistent multi-curve framework is formulated for emerging and developed inter-bank swap markets, which highlights an important dual feature of the curve-conversion factor process. Given this multi-curve framework, existing multi-curve approaches based on HJM and rational pricing kernel models are recovered, reviewed and generalised and single-curve models extended. In another application, inflation-linked, currency-based and fixed-income hybrid securities are shown to be consistently valued using the across-curve valuation method.
Optimal Sample Size for Probability of Detection Curves
International Nuclear Information System (INIS)
Annis, Charles; Gandossi, Luca; Martin, Oliver
2012-01-01
The use of Probability of Detection (POD) curves to quantify NDT reliability is common in the aeronautical industry, but relatively less so in the nuclear industry. The European Network for Inspection Qualification's (ENIQ) Inspection Qualification Methodology is based on the concept of Technical Justification, a document assembling all the evidence to assure that the NDT system in focus is indeed capable of finding the flaws for which it was designed. This methodology has become widely used in many countries, but the assurance it provides is usually of qualitative nature. The need to quantify the output of inspection qualification has become more important, especially as structural reliability modelling and quantitative risk-informed in-service inspection methodologies become more widely used. To credit the inspections in structural reliability evaluations, a measure of the NDT reliability is necessary. A POD curve provides such metric. In 2010 ENIQ developed a technical report on POD curves, reviewing the statistical models used to quantify inspection reliability. Further work was subsequently carried out to investigate the issue of optimal sample size for deriving a POD curve, so that adequate guidance could be given to the practitioners of inspection reliability. Manufacturing of test pieces with cracks that are representative of real defects found in nuclear power plants (NPP) can be very expensive. Thus there is a tendency to reduce sample sizes and in turn reduce the conservatism associated with the POD curve derived. Not much guidance on the correct sample size can be found in the published literature, where often qualitative statements are given with no further justification. The aim of this paper is to summarise the findings of such work. (author)
Construction of calibration curve for accountancy tank
International Nuclear Information System (INIS)
Kato, Takayuki; Goto, Yoshiki; Nidaira, Kazuo
2009-01-01
Tanks are equipped in a reprocessing plant for accounting solution of nuclear material. The careful measurement of volume in tanks is very important to implement rigorous accounting of nuclear material. The calibration curve relating the volume and level of solution needs to be constructed, where the level is determined by differential pressure of dip tubes. Several calibration curves are usually employed, but it's not explicitly decided how many segment are used, where to select segment, or what should be the degree of polynomial curve. These parameters, i.e., segment and degree of polynomial curve are mutually interrelated to give the better performance of calibration curve. Here we present the construction technique of giving optimum calibration curves and their characteristics. (author)
MICA: Multiple interval-based curve alignment
Mann, Martin; Kahle, Hans-Peter; Beck, Matthias; Bender, Bela Johannes; Spiecker, Heinrich; Backofen, Rolf
2018-01-01
MICA enables the automatic synchronization of discrete data curves. To this end, characteristic points of the curves' shapes are identified. These landmarks are used within a heuristic curve registration approach to align profile pairs by mapping similar characteristics onto each other. In combination with a progressive alignment scheme, this enables the computation of multiple curve alignments. Multiple curve alignments are needed to derive meaningful representative consensus data of measured time or data series. MICA was already successfully applied to generate representative profiles of tree growth data based on intra-annual wood density profiles or cell formation data. The MICA package provides a command-line and graphical user interface. The R interface enables the direct embedding of multiple curve alignment computation into larger analyses pipelines. Source code, binaries and documentation are freely available at https://github.com/BackofenLab/MICA
Inverse Diffusion Curves Using Shape Optimization.
Zhao, Shuang; Durand, Fredo; Zheng, Changxi
2018-07-01
The inverse diffusion curve problem focuses on automatic creation of diffusion curve images that resemble user provided color fields. This problem is challenging since the 1D curves have a nonlinear and global impact on resulting color fields via a partial differential equation (PDE). We introduce a new approach complementary to previous methods by optimizing curve geometry. In particular, we propose a novel iterative algorithm based on the theory of shape derivatives. The resulting diffusion curves are clean and well-shaped, and the final image closely approximates the input. Our method provides a user-controlled parameter to regularize curve complexity, and generalizes to handle input color fields represented in a variety of formats.
String Sigma Models on Curved Supermanifolds
Directory of Open Access Journals (Sweden)
Roberto Catenacci
2018-04-01
Full Text Available We use the techniques of integral forms to analyze the easiest example of two-dimensional sigma models on a supermanifold. We write the action as an integral of a top integral form over a D = 2 supermanifold, and we show how to interpolate between different superspace actions. Then, we consider curved supermanifolds, and we show that the definitions used for flat supermanifolds can also be used for curved supermanifolds. We prove it by first considering the case of a curved rigid supermanifold and then the case of a generic curved supermanifold described by a single superfield E.
Regional Marginal Abatement Cost Curves for NOx
U.S. Environmental Protection Agency — Data underlying the figures included in the manuscript "Marginal abatement cost curve for NOx incorporating controls, renewable electricity, energy efficiency and...
Optimal sample size for probability of detection curves
International Nuclear Information System (INIS)
Annis, Charles; Gandossi, Luca; Martin, Oliver
2013-01-01
Highlights: • We investigate sample size requirement to develop probability of detection curves. • We develop simulations to determine effective inspection target sizes, number and distribution. • We summarize these findings and provide guidelines for the NDE practitioner. -- Abstract: The use of probability of detection curves to quantify the reliability of non-destructive examination (NDE) systems is common in the aeronautical industry, but relatively less so in the nuclear industry, at least in European countries. Due to the nature of the components being inspected, sample sizes tend to be much lower. This makes the manufacturing of test pieces with representative flaws, in sufficient numbers, so to draw statistical conclusions on the reliability of the NDT system under investigation, quite costly. The European Network for Inspection and Qualification (ENIQ) has developed an inspection qualification methodology, referred to as the ENIQ Methodology. It has become widely used in many European countries and provides assurance on the reliability of NDE systems, but only qualitatively. The need to quantify the output of inspection qualification has become more important as structural reliability modelling and quantitative risk-informed in-service inspection methodologies become more widely used. A measure of the NDE reliability is necessary to quantify risk reduction after inspection and probability of detection (POD) curves provide such a metric. The Joint Research Centre, Petten, The Netherlands supported ENIQ by investigating the question of the sample size required to determine a reliable POD curve. As mentioned earlier manufacturing of test pieces with defects that are typically found in nuclear power plants (NPPs) is usually quite expensive. Thus there is a tendency to reduce sample sizes, which in turn increases the uncertainty associated with the resulting POD curve. The main question in conjunction with POS curves is the appropriate sample size. Not
Hong Shen
2011-01-01
The concepts of curve profile, curve intercept, curve intercept density, curve profile area density, intersection density in containing intersection (or intersection density relied on intersection reference), curve profile intersection density in surface (or curve intercept intersection density relied on intersection of containing curve), and curve profile area density in surface (AS) were defined. AS expressed the amount of curve profile area of Y phase in the unit containing surface area, S...
Polar representation of centrifugal pump homologous curves
International Nuclear Information System (INIS)
Veloso, Marcelo Antonio; Mattos, Joao Roberto Loureiro de
2008-01-01
Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic parameters: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. Any one of these quantities can be expressed as a function of any two others. The curves showing the relationships between these four variables are called the pump characteristic curves, also referred to as four-quadrant curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, the four-quadrant configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the polar form appears as the simplest way to represent the homologous curves. In the polar method, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a
Migration and the Wage-Settings Curve
DEFF Research Database (Denmark)
Brücker, Herbert; Jahn, Elke
Germany on basis of a wage-setting curve. The wage-setting curve relies on the assumption that wages respond to a hange in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously in a general equilibrium framework. Using...
Learning curves in energy planning models
Energy Technology Data Exchange (ETDEWEB)
Barreto, L; Kypreos, S [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1999-08-01
This study describes the endogenous representation of investment cost learning curves into the MARKAL energy planning model. A piece-wise representation of the learning curves is implemented using Mixed Integer Programming. The approach is briefly described and some results are presented. (author) 3 figs., 5 refs.
The Koch curve as a smooth manifold
International Nuclear Information System (INIS)
Epstein, Marcelo; Sniatycki, Jedrzej
2008-01-01
We show that there exists a homeomorphism between the closed interval [0,1] is contained in R and the Koch curve endowed with the subset topology of R 2 . We use this homeomorphism to endow the Koch curve with the structure of a smooth manifold with boundary
International Nuclear Information System (INIS)
Bershadsky, M.; Radul, A.
1988-01-01
The line bundles of degree g-1 on Z N -curves corresponding to 1/N nonsingular characteristics are considered. The determinants of Dirac operators defined on these line bundles are evaluated in terms of branch points. The generalization of Thomae's formula for Z N -curves is derived. (orig.)
Measuring Model Rocket Engine Thrust Curves
Penn, Kim; Slaton, William V.
2010-01-01
This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…
A minicourse on moduli of curves
International Nuclear Information System (INIS)
Looijenga, E.
2000-01-01
These are notes that accompany a short course given at the School on Algebraic Geometry 1999 at the ICTP, Trieste. A major goal is to outline various approaches to moduli spaces of curves. In the last part I discuss the algebraic classes that naturally live on these spaces; these can be thought of as the characteristic classes for bundles of curves. (author)
Minimal families of curves on surfaces
Lubbes, Niels
2014-01-01
A minimal family of curves on an embedded surface is defined as a 1-dimensional family of rational curves of minimal degree, which cover the surface. We classify such minimal families using constructive methods. This allows us to compute the minimal
Symmetry Properties of Potentiometric Titration Curves.
Macca, Carlo; Bombi, G. Giorgio
1983-01-01
Demonstrates how the symmetry properties of titration curves can be efficiently and rigorously treated by means of a simple method, assisted by the use of logarithmic diagrams. Discusses the symmetry properties of several typical titration curves, comparing the graphical approach and an explicit mathematical treatment. (Author/JM)
Deep-learnt classification of light curves
DEFF Research Database (Denmark)
Mahabal, Ashish; Gieseke, Fabian; Pai, Akshay Sadananda Uppinakudru
2017-01-01
Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and techniques to classify light curves. A common approach is to d...
Hyper-and-elliptic-curve cryptography
Bernstein, D.J.; Lange, T.
2014-01-01
This paper introduces ‘hyper-and-elliptic-curve cryptography’, in which a single high-security group supports fast genus-2-hyperelliptic-curve formulas for variable-base-point single-scalar multiplication (for example, Diffie–Hellman shared-secret computation) and at the same time supports fast
Curve Matching with Applications in Medical Imaging
DEFF Research Database (Denmark)
Bauer, Martin; Bruveris, Martins; Harms, Philipp
2015-01-01
In the recent years, Riemannian shape analysis of curves and surfaces has found several applications in medical image analysis. In this paper we present a numerical discretization of second order Sobolev metrics on the space of regular curves in Euclidean space. This class of metrics has several...
Micro photometer's automation for quantitative spectrograph analysis
International Nuclear Information System (INIS)
Gutierrez E, C.Y.A.
1996-01-01
A Microphotometer is used to increase the sharpness of dark spectral lines. Analyzing these lines one sample content and its concentration could be determined and the analysis is known as Quantitative Spectrographic Analysis. The Quantitative Spectrographic Analysis is carried out in 3 steps, as follows. 1. Emulsion calibration. This consists of gauging a photographic emulsion, to determine the intensity variations in terms of the incident radiation. For the procedure of emulsion calibration an adjustment with square minimum to the data obtained is applied to obtain a graph. It is possible to determine the density of dark spectral line against the incident light intensity shown by the microphotometer. 2. Working curves. The values of known concentration of an element against incident light intensity are plotted. Since the sample contains several elements, it is necessary to find a work curve for each one of them. 3. Analytical results. The calibration curve and working curves are compared and the concentration of the studied element is determined. The automatic data acquisition, calculation and obtaining of resulting, is done by means of a computer (PC) and a computer program. The conditioning signal circuits have the function of delivering TTL levels (Transistor Transistor Logic) to make the communication between the microphotometer and the computer possible. Data calculation is done using a computer programm
Remote sensing used for power curves
International Nuclear Information System (INIS)
Wagner, R; Joergensen, H E; Paulsen, U S; Larsen, T J; Antoniou, I; Thesbjerg, L
2008-01-01
Power curve measurement for large wind turbines requires taking into account more parameters than only the wind speed at hub height. Based on results from aerodynamic simulations, an equivalent wind speed taking the wind shear into account was defined and found to reduce the power standard deviation in the power curve significantly. Two LiDARs and a SoDAR are used to measure the wind profile in front of a wind turbine. These profiles are used to calculate the equivalent wind speed. The comparison of the power curves obtained with the three instruments to the traditional power curve, obtained using a cup anemometer measurement, confirms the results obtained from the simulations. Using LiDAR profiles reduces the error in power curve measurement, when these are used as relative instrument together with a cup anemometer. Results from the SoDAR do not show such promising results, probably because of noisy measurements resulting in distorted profiles
Hysteresis and uncertainty in soil water-retention curve parameters
Likos, William J.; Lu, Ning; Godt, Jonathan W.
2014-01-01
Accurate estimates of soil hydraulic parameters representing wetting and drying paths are required for predicting hydraulic and mechanical responses in a large number of applications. A comprehensive suite of laboratory experiments was conducted to measure hysteretic soil-water characteristic curves (SWCCs) representing a wide range of soil types. Results were used to quantitatively assess differences and uncertainty in three simplifications frequently adopted to estimate wetting-path SWCC parameters from more easily measured drying curves. They are the following: (1) αw=2αd, (2) nw=nd, and (3) θws=θds, where α, n, and θs are fitting parameters entering van Genuchten’s commonly adopted SWCC model, and the superscripts w and d indicate wetting and drying paths, respectively. The average ratio αw/αd for the data set was 2.24±1.25. Nominally cohesive soils had a lower αw/αd ratio (1.73±0.94) than nominally cohesionless soils (3.14±1.27). The average nw/nd ratio was 1.01±0.11 with no significant dependency on soil type, thus confirming the nw=nd simplification for a wider range of soil types than previously available. Water content at zero suction during wetting (θws) was consistently less than during drying (θds) owing to air entrapment. The θws/θds ratio averaged 0.85±0.10 and was comparable for nominally cohesive (0.87±0.11) and cohesionless (0.81±0.08) soils. Regression statistics are provided to quantitatively account for uncertainty in estimating hysteretic retention curves. Practical consequences are demonstrated for two case studies.
Parametric representation of centrifugal pump homologous curves
International Nuclear Information System (INIS)
Veloso, Marcelo A.; Mattos, Joao R.L. de
2015-01-01
Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic quantities: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. The curves showing the relationships between these four variables are called the pump characteristic curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, this configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the parametric form appears as the simplest way to deal with the homologous curves. In this approach, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a pressurized water reactor (PWR) are transformed to the parametric form. (author)
The utility of laboratory animal data in toxicology depends upon the ability to generalize the results quantitatively to humans. To compare the acute behavioral effects of inhaled toluene in humans to those in animals, dose-effect curves were fitted by meta-analysis of published...
International Nuclear Information System (INIS)
Bergmann, H.; Mostbeck, A.; Samal, M.; Nimmon, C.C.; Staudenherz, A.; Dudczak, R.
2002-01-01
Aim: In a previous work, we have confirmed earlier reports that time-activity curves of renal cortex provide additional useful diagnostic information. The aim of this experiment was to support the finding quantitatively using multiple regression. Materials and Methods: In a retrospective study, we have analyzed MAG3 renal data (90 kidneys in 57 children). Whole-kidney (WK) and parenchymal (PA) time-activity curves were extracted from 20 min pre-diuretic phase using standard WK and parenchymal fuzzy ROIs. Using multiple regression analysis, peak time, mean transit time, output efficiency, and four additional indices of residual activity in WK and PA ROIs were related to the maximum elimination rate (EM) of urine after the diuretic. The kidneys were divided into four groups according to the WK peak time (WKPT): WKPT longer than 0 (all kidneys), 5, 10, and 15 min. Results: Multiple correlation coefficients between the set of WK, PA, and WK+PA curve parameters (independent variables) and the log EM (dependent variable) for each group are summarized. Conclusions: Using pre-diuretic time-activity curves, it is possible to predict diuretic response. This can be useful when interpreting dubious results. Parenchymal curves predict diuretic response better than the whole-kidney curves. With increasing WKPT the whole-kidney curves become useless, while the parenchymal curves are still useful. Using both WK and PA curves produces the best results. This demonstrates that both WK and PA curves carry independent diagnostic information. The contribution obtained from the parenchymal curves certainly worth the difficulties and time required to draw additional ROIs. However, substantial efforts have to be given to the accurate and reproducible definition of parenchymal ROIs
Computerised curve deconvolution of TL/OSL curves using a popular spreadsheet program.
Afouxenidis, D; Polymeris, G S; Tsirliganis, N C; Kitis, G
2012-05-01
This paper exploits the possibility of using commercial software for thermoluminescence and optically stimulated luminescence curve deconvolution analysis. The widely used software package Microsoft Excel, with the Solver utility has been used to perform deconvolution analysis to both experimental and reference glow curves resulted from the GLOw Curve ANalysis INtercomparison project. The simple interface of this programme combined with the powerful Solver utility, allows the analysis of complex stimulated luminescence curves into their components and the evaluation of the associated luminescence parameters.
Computerised curve deconvolution of TL/OSL curves using a popular spreadsheet program
International Nuclear Information System (INIS)
Afouxenidis, D.; Polymeris, G. S.; Tsirliganis, N. C.; Kitis, G.
2012-01-01
This paper exploits the possibility of using commercial software for thermoluminescence and optically stimulated luminescence curve deconvolution analysis. The widely used software package Microsoft Excel, with the Solver utility has been used to perform deconvolution analysis to both experimental and reference glow curves resulted from the Glow Curve Analysis Intercomparison project. The simple interface of this programme combined with the powerful Solver utility, allows the analysis of complex stimulated luminescence curves into their components and the evaluation of the associated luminescence parameters. (authors)
Mannheim Partner D-Curves in the Euclidean 3-space
Directory of Open Access Journals (Sweden)
Mustafa Kazaz
2015-02-01
Full Text Available In this paper, we consider the idea of Mannheim partner curves for curves lying on surfaces. By considering the Darboux frames of surface curves, we define Mannheim partner D-curves and give the characterizations for these curves. We also find the relations between geodesic curvatures, normal curvatures and geodesic torsions of these associated curves. Furthermore, we show that definition and characterizations of Mannheim partner D-curves include those of Mannheim partner curves in some special cases.
A versatile curve-fit model for linear to deeply concave rank abundance curves
Neuteboom, J.H.; Struik, P.C.
2005-01-01
A new, flexible curve-fit model for linear to concave rank abundance curves was conceptualized and validated using observational data. The model links the geometric-series model and log-series model and can also fit deeply concave rank abundance curves. The model is based ¿ in an unconventional way
Quantitative investment analysis
DeFusco, Richard
2007-01-01
In the "Second Edition" of "Quantitative Investment Analysis," financial experts Richard DeFusco, Dennis McLeavey, Jerald Pinto, and David Runkle outline the tools and techniques needed to understand and apply quantitative methods to today's investment process.
A Bayesian hierarchical model for demand curve analysis.
Ho, Yen-Yi; Nhu Vo, Tien; Chu, Haitao; Luo, Xianghua; Le, Chap T
2018-07-01
Drug self-administration experiments are a frequently used approach to assessing the abuse liability and reinforcing property of a compound. It has been used to assess the abuse liabilities of various substances such as psychomotor stimulants and hallucinogens, food, nicotine, and alcohol. The demand curve generated from a self-administration study describes how demand of a drug or non-drug reinforcer varies as a function of price. With the approval of the 2009 Family Smoking Prevention and Tobacco Control Act, demand curve analysis provides crucial evidence to inform the US Food and Drug Administration's policy on tobacco regulation, because it produces several important quantitative measurements to assess the reinforcing strength of nicotine. The conventional approach popularly used to analyze the demand curve data is individual-specific non-linear least square regression. The non-linear least square approach sets out to minimize the residual sum of squares for each subject in the dataset; however, this one-subject-at-a-time approach does not allow for the estimation of between- and within-subject variability in a unified model framework. In this paper, we review the existing approaches to analyze the demand curve data, non-linear least square regression, and the mixed effects regression and propose a new Bayesian hierarchical model. We conduct simulation analyses to compare the performance of these three approaches and illustrate the proposed approaches in a case study of nicotine self-administration in rats. We present simulation results and discuss the benefits of using the proposed approaches.
Automated curved planar reformation of 3D spine images
International Nuclear Information System (INIS)
Vrtovec, Tomaz; Likar, Bostjan; Pernus, Franjo
2005-01-01
Traditional techniques for visualizing anatomical structures are based on planar cross-sections from volume images, such as images obtained by computed tomography (CT) or magnetic resonance imaging (MRI). However, planar cross-sections taken in the coordinate system of the 3D image often do not provide sufficient or qualitative enough diagnostic information, because planar cross-sections cannot follow curved anatomical structures (e.g. arteries, colon, spine, etc). Therefore, not all of the important details can be shown simultaneously in any planar cross-section. To overcome this problem, reformatted images in the coordinate system of the inspected structure must be created. This operation is usually referred to as curved planar reformation (CPR). In this paper we propose an automated method for CPR of 3D spine images, which is based on the image transformation from the standard image-based to a novel spine-based coordinate system. The axes of the proposed spine-based coordinate system are determined on the curve that represents the vertebral column, and the rotation of the vertebrae around the spine curve, both of which are described by polynomial models. The optimal polynomial parameters are obtained in an image analysis based optimization framework. The proposed method was qualitatively and quantitatively evaluated on five CT spine images. The method performed well on both normal and pathological cases and was consistent with manually obtained ground truth data. The proposed spine-based CPR benefits from reduced structural complexity in favour of improved feature perception of the spine. The reformatted images are diagnostically valuable and enable easier navigation, manipulation and orientation in 3D space. Moreover, reformatted images may prove useful for segmentation and other image analysis tasks
Rigour in quantitative research.
Claydon, Leica Sarah
2015-07-22
This article which forms part of the research series addresses scientific rigour in quantitative research. It explores the basis and use of quantitative research and the nature of scientific rigour. It examines how the reader may determine whether quantitative research results are accurate, the questions that should be asked to determine accuracy and the checklists that may be used in this process. Quantitative research has advantages in nursing, since it can provide numerical data to help answer questions encountered in everyday practice.
Investigation of learning and experience curves
Energy Technology Data Exchange (ETDEWEB)
Krawiec, F.; Thornton, J.; Edesess, M.
1980-04-01
The applicability of learning and experience curves for predicting future costs of solar technologies is assessed, and the major test case is the production economics of heliostats. Alternative methods for estimating cost reductions in systems manufacture are discussed, and procedures for using learning and experience curves to predict costs are outlined. Because adequate production data often do not exist, production histories of analogous products/processes are analyzed and learning and aggregated cost curves for these surrogates estimated. If the surrogate learning curves apply, they can be used to estimate solar technology costs. The steps involved in generating these cost estimates are given. Second-generation glass-steel and inflated-bubble heliostat design concepts, developed by MDAC and GE, respectively, are described; a costing scenario for 25,000 units/yr is detailed; surrogates for cost analysis are chosen; learning and aggregate cost curves are estimated; and aggregate cost curves for the GE and MDAC designs are estimated. However, an approach that combines a neoclassical production function with a learning-by-doing hypothesis is needed to yield a cost relation compatible with the historical learning curve and the traditional cost function of economic theory.
Quantitation: clinical applications
International Nuclear Information System (INIS)
Britton, K.E.
1982-01-01
Single photon emission tomography may be used quantitatively if its limitations are recognized and quantitation is made in relation to some reference area on the image. Relative quantitation is discussed in outline in relation to the liver, brain and pituitary, thyroid, adrenals, and heart. (U.K.)
Modelling curves of manufacturing feasibilities and demand
Directory of Open Access Journals (Sweden)
Soloninko K.S.
2017-03-01
Full Text Available The authors research the issue of functional properties of curves of manufacturing feasibilities and demand. Settlement of the problem, and its connection with important scientific and practical tasks. According to its nature, the market economy is unstable and is in constant movement. Economy has an effective instrument for explanation of changes in economic environment; this tool is called the modelling of economic processes. The modelling of economic processes depends first and foremost on the building of economic model which is the base for the formalization of economic process, that is, the building of mathematical model. The effective means for formalization of economic process is the creation of the model of hypothetic or imaginary economy. The building of demand model is significant for the market of goods and services. The problem includes the receiving (as the result of modelling definite functional properties of curves of manufacturing feasibilities and demand according to which one can determine their mathematical model. Another problem lies in obtaining majorant properties of curves of joint demand on the market of goods and services. Analysis of the latest researches and publications. Many domestic and foreign scientists dedicated their studies to the researches and building of the models of curves of manufacturing feasibilities and demand. In spite of considerable work of the scientists, such problems as functional properties of the curves and their practical use in modelling. The purpose of the article is to describe functional properties of curves of manufacturing feasibilities and demand on the market of goods and services on the base of modelling of their building. Scientific novelty and practical value. The theoretical regulations (for functional properties of curves of manufacturing feasibilities and demand received as a result of the present research, that is convexity, give extra practical possibilities in a microeconomic
Reflected Light Curves of Extrasolar Planets
Green, D.; Matthews, J.; Kuschnig, R.; Seager, S.
The planned launches of ultra-precise photometric satellites such as MOST, COROT and MONS should provide the first opportunity to study the reflected light curves from extrasolar planets. To predict the capabilities of these missions, we have constructed a series of models of such light curves, improving upon the Monte Carlo simulations by Seager et al. (2000). These models include more realistic features such limb darkening of the star and broad band photometry. For specific models, the resulting planet light curves exhibit unique behavior with the variation of radius, inclination and presence or absence of clouds.
Neck curve polynomials in neck rupture model
International Nuclear Information System (INIS)
Kurniadi, Rizal; Perkasa, Yudha S.; Waris, Abdul
2012-01-01
The Neck Rupture Model is a model that explains the scission process which has smallest radius in liquid drop at certain position. Old fashion of rupture position is determined randomly so that has been called as Random Neck Rupture Model (RNRM). The neck curve polynomials have been employed in the Neck Rupture Model for calculation the fission yield of neutron induced fission reaction of 280 X 90 with changing of order of polynomials as well as temperature. The neck curve polynomials approximation shows the important effects in shaping of fission yield curve.
Morse theory on timelike and causal curves
International Nuclear Information System (INIS)
Everson, J.; Talbot, C.J.
1976-01-01
It is shown that the set of timelike curves in a globally hyperbolic space-time manifold can be given the structure of a Hilbert manifold under a suitable definition of 'timelike.' The causal curves are the topological closure of this manifold. The Lorentzian energy (corresponding to Milnor's energy, except that the Lorentzian inner product is used) is shown to be a Morse function for the space of causal curves. A fixed end point index theorem is obtained in which a lower bound for the index of the Hessian of the Lorentzian energy is given in terms of the sum of the orders of the conjugate points between the end points. (author)
Constructing forward price curves in electricity markets
DEFF Research Database (Denmark)
Fleten, S.-E.; Lemming, Jørgen Kjærgaard
2003-01-01
We present and analyze a method for constructing approximated high-resolution forward price curves in electricity markets. Because a limited number of forward or futures contracts are traded in the market, only a limited picture of the theoretical continuous forward price curve is available...... to the analyst. Our method combines the information contained in observed bid and ask prices with information from the forecasts generated by bottom-up models. As an example, we use information concerning the shape of the seasonal variation from a bottom-up model to improve the forward price curve quoted...
Curves of restricted type in euclidean spaces
Directory of Open Access Journals (Sweden)
Bengü Kılıç Bayram
2014-01-01
Full Text Available Submanifolds of restricted type were introduced in [7]. In the present study we consider restricted type of curves in Em. We give some special examples. We also show that spherical curve in S2(r C E3 is of restricted type if and only if either ƒ(s is constant or a linear function of s of the form ƒ(s = ±s + b and every closed W - curve of rank k and of length 2(r in E2k is of restricted type.
Constructing forward price curves in electricity markets
International Nuclear Information System (INIS)
Fleten, Stein-Erik; Lemming, Jacob
2003-01-01
We present and analyze a method for constructing approximated high-resolution forward price curves in electricity markets. Because a limited number of forward or futures contracts are traded in the market, only a limited picture of the theoretical continuous forward price curve is available to the analyst. Our method combines the information contained in observed bid and ask prices with information from the forecasts generated by bottom-up models. As an example, we use information concerning the shape of the seasonal variation from a bottom-up model to improve the forward price curve quoted on the Nordic power exchange
Growth curves for twins in Slovenia.
Bricelj, Katja; Blickstein, Isaac; Bržan-Šimenc, Gabrijela; Janša, Vid; Lučovnik, Miha; Verdenik, Ivan; Trojner-Bregar, Andreja; Tul, Nataša
2017-02-01
Abnormalities of fetal growth are more common in twins. We introduce the growth curves for monitoring fetal growth in twin pregnancies in Slovenia. Slovenian National Perinatal Information System for the period between 2002 and 2010 was used to calculate birth weight percentiles for all live born twins for each week from 22nd to 40th week. The calculated percentiles of birth weight for all live-born twins in Slovenia served as the basis for drawing 'growth' curves. The calculated growth curves for twins will help accurately diagnose small or large twin fetuses for their gestational age in the native central European population.
Wind Turbine Power Curves Incorporating Turbulence Intensity
DEFF Research Database (Denmark)
Sørensen, Emil Hedevang Lohse
2014-01-01
. The model and method are parsimonious in the sense that only a single function (the zero-turbulence power curve) and a single auxiliary parameter (the equivalent turbulence factor) are needed to predict the mean power at any desired turbulence intensity. The method requires only ten minute statistics......The performance of a wind turbine in terms of power production (the power curve) is important to the wind energy industry. The current IEC-61400-12-1 standard for power curve evaluation recognizes only the mean wind speed at hub height and the air density as relevant to the power production...
Extracting 3D Parametric Curves from 2D Images of Helical Objects.
Willcocks, Chris G; Jackson, Philip T G; Nelson, Carl J; Obara, Boguslaw
2017-09-01
Helical objects occur in medicine, biology, cosmetics, nanotechnology, and engineering. Extracting a 3D parametric curve from a 2D image of a helical object has many practical applications, in particular being able to extract metrics such as tortuosity, frequency, and pitch. We present a method that is able to straighten the image object and derive a robust 3D helical curve from peaks in the object boundary. The algorithm has a small number of stable parameters that require little tuning, and the curve is validated against both synthetic and real-world data. The results show that the extracted 3D curve comes within close Hausdorff distance to the ground truth, and has near identical tortuosity for helical objects with a circular profile. Parameter insensitivity and robustness against high levels of image noise are demonstrated thoroughly and quantitatively.
International Nuclear Information System (INIS)
Pan, Haoran; Koehler, Jonathan
2007-01-01
Learning curves have recently been widely adopted in climate-economy models to incorporate endogenous change of energy technologies, replacing the conventional assumption of an autonomous energy efficiency improvement. However, there has been little consideration of the credibility of the learning curve. The current trend that many important energy and climate change policy analyses rely on the learning curve means that it is of great importance to critically examine the basis for learning curves. Here, we analyse the use of learning curves in energy technology, usually implemented as a simple power function. We find that the learning curve cannot separate the effects of price and technological change, cannot reflect continuous and qualitative change of both conventional and emerging energy technologies, cannot help to determine the time paths of technological investment, and misses the central role of R and D activity in driving technological change. We argue that a logistic curve of improving performance modified to include R and D activity as a driving variable can better describe the cost reductions in energy technologies. Furthermore, we demonstrate that the top-down Leontief technology can incorporate the bottom-up technologies that improve along either the learning curve or the logistic curve, through changing input-output coefficients. An application to UK wind power illustrates that the logistic curve fits the observed data better and implies greater potential for cost reduction than the learning curve does. (author)
A simple Lissajous curves experimental setup
Şahin Kızılcık, Hasan; Damlı, Volkan
2018-05-01
The aim of this study is to develop an experimental setup to produce Lissajous curves. The setup was made using a smartphone, a powered speaker (computer speaker), a balloon, a laser pointer and a piece of mirror. Lissajous curves are formed as follows: a piece of mirror is attached to a balloon. The balloon is vibrated with the sound signal provided by the speaker that is connected to a smartphone. The laser beam is reflected off the mirror and the reflection is shaped as a Lissajous curve. Because of the intersection of two frequencies (frequency of the sound signal and natural vibration frequency of the balloon), these curves are formed. They can be used to measure the ratio of frequencies.
On ``minimally curved spacetimes'' in general relativity
Dadhich, Naresh
1997-01-01
We consider a spacetime corresponding to uniform relativistic potential analogus to Newtonian potential as an example of ``minimally curved spacetime''. We also consider a radially symmetric analogue of the Rindler spacetime of uniform proper acceleration relative to infinity.
Utilization of curve offsets in additive manufacturing
Haseltalab, Vahid; Yaman, Ulas; Dolen, Melik
2018-05-01
Curve offsets are utilized in different fields of engineering and science. Additive manufacturing, which lately becomes an explicit requirement in manufacturing industry, utilizes curve offsets widely. One of the necessities of offsetting is for scaling which is required if there is shrinkage after the fabrication or if the surface quality of the resulting part is unacceptable. Therefore, some post-processing is indispensable. But the major application of curve offsets in additive manufacturing processes is for generating head trajectories. In a point-wise AM process, a correct tool-path in each layer can reduce lots of costs and increase the surface quality of the fabricated parts. In this study, different curve offset generation algorithms are analyzed to show their capabilities and disadvantages through some test cases and improvements on their drawbacks are suggested.
Quaternion orders, quadratic forms, and Shimura curves
Alsina, Montserrat
2004-01-01
Shimura curves are a far-reaching generalization of the classical modular curves. They lie at the crossroads of many areas, including complex analysis, hyperbolic geometry, algebraic geometry, algebra, and arithmetic. The text provides an introduction to the subject from a theoretic and algorithmic perspective. The main topics covered in it are Shimura curves defined over the rational number field, the construction of their fundamental domains, and the determination of their complex multiplication points. The study of complex multiplication points in Shimura curves leads to the study of families of binary quadratic forms with algebraic coefficients and to their classification by arithmetic Fuchsian groups. In this regard, the authors develop a theory full of new possibilities which parallels Gauss' theory on the classification of binary quadratic forms with integral coefficients by the action of the modular group. Each topic covered in the book begins with a theoretical discussion followed by carefully worked...
Uncovering the skewness news impact curve
Czech Academy of Sciences Publication Activity Database
Anatolyev, Stanislav; Petukhov, A.
2016-01-01
Roč. 14, č. 4 (2016), s. 746-771 ISSN 1479-8409 Institutional support: RVO:67985998 Keywords : conditional skewness * news impact curve * stock returns Subject RIV: AH - Economics Impact factor: 1.800, year: 2016
Classification of ASKAP Vast Radio Light Curves
Rebbapragada, Umaa; Lo, Kitty; Wagstaff, Kiri L.; Reed, Colorado; Murphy, Tara; Thompson, David R.
2012-01-01
The VAST survey is a wide-field survey that observes with unprecedented instrument sensitivity (0.5 mJy or lower) and repeat cadence (a goal of 5 seconds) that will enable novel scientific discoveries related to known and unknown classes of radio transients and variables. Given the unprecedented observing characteristics of VAST, it is important to estimate source classification performance, and determine best practices prior to the launch of ASKAP's BETA in 2012. The goal of this study is to identify light curve characterization and classification algorithms that are best suited for archival VAST light curve classification. We perform our experiments on light curve simulations of eight source types and achieve best case performance of approximately 90% accuracy. We note that classification performance is most influenced by light curve characterization rather than classifier algorithm.
Automorphisms of double coverings of curves
International Nuclear Information System (INIS)
Torres, F.
1994-11-01
We study automorphisms of curves that commute with each other. We prove that the order and the number of fixed points of one of them satisfy certain relations involving those of the other. Then, we specialize our results to the case of double coverings of curves. For instance, if the genus of the curve is at least 4γ + 2 and γ >= 1 (γ = the genus of the covered curve) we prove that the order of an automorphism is bounded above by 2γ + 1 (resp. 4γ + 2) provided it is prime (resp. it has at least five fixed points). We also improve Farkas' bound on the number of fixed points namely 4γ + 4 by showing that it involves the order of the automorphism except in the case of even order when such an improvement is obtained provided the automorphism and the γ-involution has at least one common fixed point. (author). 15 refs
Uncovering the skewness news impact curve
Czech Academy of Sciences Publication Activity Database
Anatolyev, Stanislav; Petukhov, A.
2016-01-01
Roč. 14, č. 4 (2016), s. 746-771 ISSN 1479-8409 Institutional support: PRVOUK-P23 Keywords : conditional skewness * news impact curve * stock returns Subject RIV: AH - Economics Impact factor: 1.800, year: 2016
Transmission of wave energy in curved ducts
Rostafinski, W.
1973-01-01
A formation of wave energy flow was developed for motion in curved ducts. A parametric study over a range of frequencies determined the ability of circular bends to transmit energy for the case of perfectly rigid walls.
Twisted Vector Bundles on Pointed Nodal Curves
Indian Academy of Sciences (India)
Abstract. Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich's and Vistoli's twisted bundles and Gieseker vector bundles.
Statistics from dynamics in curved spacetime
International Nuclear Information System (INIS)
Parker, L.; Wang, Y.
1989-01-01
We consider quantum fields of spin 0, 1/2, 1, 3/2, and 2 with a nonzero mass in curved spacetime. We show that the dynamical Bogolubov transformations associated with gravitationally induced particle creation imply the connection between spin and statistics: By embedding two flat regions in a curved spacetime, we find that only when one imposes Bose-Einstein statistics for an integer-spin field and Fermi-Dirac statistics for a half-integer-spin field in the first flat region is the same type of statistics propagated from the first to the second flat region. This derivation of the flat-spacetime spin-statistics theorem makes use of curved-spacetime dynamics and does not reduce to any proof given in flat spacetime. We also show in the same manner that parastatistics, up to the fourth order, are consistent with the dynamical evolution of curved spacetime
RMS fatigue curves for random vibrations
International Nuclear Information System (INIS)
Brenneman, B.; Talley, J.G.
1984-01-01
Fatigue usage factors for deterministic or constant amplitude vibration stresses may be calculated with well known procedures and fatigue curves given in the ASME Boiler and Pressure Vessel Code. However, some phenomena produce nondeterministic cyclic stresses which can only be described and analyzed with statistical concepts and methods. Such stresses may be caused by turbulent fluid flow over a structure. Previous methods for solving this statistical fatigue problem are often difficult to use and may yield inaccurate results. Two such methods examined herein are Crandall's method and the ''3sigma'' method. The objective of this paper is to provide a method for creating ''RMS fatigue curves'' which accurately incorporate the requisite statistical information. These curves are given and may be used by analysts with the same ease and in the same manner as the ASME fatigue curves
Application of harmonic analysis in quantitative heart scintigraphy
International Nuclear Information System (INIS)
Fischer, P.; Knopp, R.; Breuel, H.P.
1979-01-01
Quantitative scintigraphy of the heart after equilibrium distribution of a radioactive tracer permits the measurement of time activity curves in the left ventricle during a representative heart cycle with great statistical accuracy. By application of Fourier's analysis, criteria are to be attained in addition for evaluation of the volume curve as a whole. Thus the entire information contained in the volume curve is completely described in a Fourier spectrum. Resynthesis after Fourier transformation seems to be an ideal method of smoothing because of its convergence in the minimum quadratic error for the type of function concerned. (orig./MG) [de
Neutron cross sections: Book of curves
International Nuclear Information System (INIS)
McLane, V.; Dunford, C.L.; Rose, P.F.
1988-01-01
Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross sections have been included. 11 refs., 4 figs
Constructing elliptic curves from Galois representations
Snowden, Andrew; Tsimerman, Jacob
2017-01-01
Given a non-isotrivial elliptic curve over an arithmetic surface, one obtains a lisse $\\ell$-adic sheaf of rank two over the surface. This lisse sheaf has a number of straightforward properties: cyclotomic determinant, finite ramification, rational traces of Frobenius, and somewhere not potentially good reduction. We prove that any lisse sheaf of rank two possessing these properties comes from an elliptic curve.
Curved twistor spaces and H-space
International Nuclear Information System (INIS)
Tod, K.P.
1980-01-01
The curved twistor space construction of Penrose for anti-self-dual solutions to the Einstein vacuum equations is described. Curved twistor spaces are defined and it is shown with the aid of an example how to obtain them by deforming the complex structure of regions of flat twistor space. The connection of this procedure with Newman's H-space construction via asymptotic twistor space is outlined. (Auth.)
Potential Energy Curve of N2 Revisited
Czech Academy of Sciences Publication Activity Database
Špirko, Vladimír; Xiangzhu, L.; Paldus, J.
2011-01-01
Roč. 76, č. 4 (2011), s. 327-341 ISSN 0010-0765 R&D Projects: GA MŠk LC512; GA ČR GAP208/11/0436 Institutional research plan: CEZ:AV0Z40550506 Keywords : reduced multireference coupled-cluster method * reduced potential curve method * nitrogen molecule potential energy curves Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.283, year: 2011
Anomalies in curved spacetime at finite temperature
International Nuclear Information System (INIS)
Boschi-Filho, H.; Natividade, C.P.
1993-01-01
We discuss the problem of the breakdown of conformal and gauge symmetries at finite temperature in curved spacetime background, when the changes in the background are gradual. We obtain the expressions for the Seeley's coefficients and the heat kernel expansion in this regime. As applications, we consider the self-interacting lambda phi''4 and chiral Schwinger models in curved backgrounds at finite temperature. (Author) 9 refs
Learning curves in health professions education.
Pusic, Martin V; Boutis, Kathy; Hatala, Rose; Cook, David A
2015-08-01
Learning curves, which graphically show the relationship between learning effort and achievement, are common in published education research but are not often used in day-to-day educational activities. The purpose of this article is to describe the generation and analysis of learning curves and their applicability to health professions education. The authors argue that the time is right for a closer look at using learning curves-given their desirable properties-to inform both self-directed instruction by individuals and education management by instructors.A typical learning curve is made up of a measure of learning (y-axis), a measure of effort (x-axis), and a mathematical linking function. At the individual level, learning curves make manifest a single person's progress towards competence including his/her rate of learning, the inflection point where learning becomes more effortful, and the remaining distance to mastery attainment. At the group level, overlaid learning curves show the full variation of a group of learners' paths through a given learning domain. Specifically, they make overt the difference between time-based and competency-based approaches to instruction. Additionally, instructors can use learning curve information to more accurately target educational resources to those who most require them.The learning curve approach requires a fine-grained collection of data that will not be possible in all educational settings; however, the increased use of an assessment paradigm that explicitly includes effort and its link to individual achievement could result in increased learner engagement and more effective instructional design.
Environmental bias and elastic curves on surfaces
International Nuclear Information System (INIS)
Guven, Jemal; María Valencia, Dulce; Vázquez-Montejo, Pablo
2014-01-01
The behavior of an elastic curve bound to a surface will reflect the geometry of its environment. This may occur in an obvious way: the curve may deform freely along directions tangent to the surface, but not along the surface normal. However, even if the energy itself is symmetric in the curve's geodesic and normal curvatures, which control these modes, very distinct roles are played by the two. If the elastic curve binds preferentially on one side, or is itself assembled on the surface, not only would one expect the bending moduli associated with the two modes to differ, binding along specific directions, reflected in spontaneous values of these curvatures, may be favored. The shape equations describing the equilibrium states of a surface curve described by an elastic energy accommodating environmental factors will be identified by adapting the method of Lagrange multipliers to the Darboux frame associated with the curve. The forces transmitted to the surface along the surface normal will be determined. Features associated with a number of different energies, both of physical relevance and of mathematical interest, are described. The conservation laws associated with trajectories on surface geometries exhibiting continuous symmetries are also examined. (paper)
Geometric invariant theory for polarized curves
Bini, Gilberto; Melo, Margarida; Viviani, Filippo
2014-01-01
We investigate GIT quotients of polarized curves. More specifically, we study the GIT problem for the Hilbert and Chow schemes of curves of degree d and genus g in a projective space of dimension d-g, as d decreases with respect to g. We prove that the first three values of d at which the GIT quotients change are given by d=a(2g-2) where a=2, 3.5, 4. We show that, for a>4, L. Caporaso's results hold true for both Hilbert and Chow semistability. If 3.5curves. If 2curves. We also analyze in detail the critical values a=3.5 and a=4, where the Hilbert semistable locus is strictly smaller than the Chow semistable locus. As an application, we obtain three compactications of the universal Jacobian over the moduli space of stable curves, weakly-pseudo-stable curves and pseu...
Global experience curves for wind farms
International Nuclear Information System (INIS)
Junginger, M.; Faaij, A.; Turkenburg, W.C.
2005-01-01
In order to forecast the technological development and cost of wind turbines and the production costs of wind electricity, frequent use is made of the so-called experience curve concept. Experience curves of wind turbines are generally based on data describing the development of national markets, which cause a number of problems when applied for global assessments. To analyze global wind energy price development more adequately, we compose a global experience curve. First, underlying factors for past and potential future price reductions of wind turbines are analyzed. Also possible implications and pitfalls when applying the experience curve methodology are assessed. Second, we present and discuss a new approach of establishing a global experience curve and thus a global progress ratio for the investment cost of wind farms. Results show that global progress ratios for wind farms may lie between 77% and 85% (with an average of 81%), which is significantly more optimistic than progress ratios applied in most current scenario studies and integrated assessment models. While the findings are based on a limited amount of data, they may indicate faster price reduction opportunities than so far assumed. With this global experience curve we aim to improve the reliability of describing the speed with which global costs of wind power may decline
Stenting for curved lesions using a novel curved balloon: Preliminary experimental study.
Tomita, Hideshi; Higaki, Takashi; Kobayashi, Toshiki; Fujii, Takanari; Fujimoto, Kazuto
2015-08-01
Stenting may be a compelling approach to dilating curved lesions in congenital heart diseases. However, balloon-expandable stents, which are commonly used for congenital heart diseases, are usually deployed in a straight orientation. In this study, we evaluated the effect of stenting with a novel curved balloon considered to provide better conformability to the curved-angled lesion. In vitro experiments: A Palmaz Genesis(®) stent (Johnson & Johnson, Cordis Co, Bridgewater, NJ, USA) mounted on the Goku(®) curve (Tokai Medical Co. Nagoya, Japan) was dilated in vitro to observe directly the behavior of the stent and balloon assembly during expansion. Animal experiment: A short Express(®) Vascular SD (Boston Scientific Co, Marlborough, MA, USA) stent and a long Express(®) Vascular LD stent (Boston Scientific) mounted on the curved balloon were deployed in the curved vessel of a pig to observe the effect of stenting in vivo. In vitro experiments: Although the stent was dilated in a curved fashion, stent and balloon assembly also rotated conjointly during expansion of its curved portion. In the primary stenting of the short stent, the stent was dilated with rotation of the curved portion. The excised stent conformed to the curved vessel. As the long stent could not be negotiated across the mid-portion with the balloon in expansion when it started curving, the mid-portion of the stent failed to expand fully. Furthermore, the balloon, which became entangled with the stent strut, could not be retrieved even after complete deflation. This novel curved balloon catheter might be used for implantation of the short stent in a curved lesion; however, it should not be used for primary stenting of the long stent. Post-dilation to conform the stent to the angled vessel would be safer than primary stenting irrespective of stent length. Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
Development of the curve of Spee.
Marshall, Steven D; Caspersen, Matthew; Hardinger, Rachel R; Franciscus, Robert G; Aquilino, Steven A; Southard, Thomas E
2008-09-01
Ferdinand Graf von Spee is credited with characterizing human occlusal curvature viewed in the sagittal plane. This naturally occurring phenomenon has clinical importance in orthodontics and restorative dentistry, yet we have little understanding of when, how, or why it develops. The purpose of this study was to expand our understanding by examining the development of the curve of Spee longitudinally in a sample of untreated subjects with normal occlusion from the deciduous dentition to adulthood. Records of 16 male and 17 female subjects from the Iowa Facial Growth Study were selected and examined. The depth of the curve of Spee was measured on their study models at 7 time points from ages 4 (deciduous dentition) to 26 (adult dentition) years. The Wilcoxon signed rank test was used to compare changes in the curve of Spee depth between time points. For each subject, the relative eruption of the mandibular teeth was measured from corresponding cephalometric radiographs, and its contribution to the developing curve of Spee was ascertained. In the deciduous dentition, the curve of Spee is minimal. At mean ages of 4.05 and 5.27 years, the average curve of Spee depths are 0.24 and 0.25 mm, respectively. With change to the transitional dentition, corresponding to the eruption of the mandibular permanent first molars and central incisors (mean age, 6.91 years), the curve of Spee depth increases significantly (P < 0.0001) to a mean maximum depth of 1.32 mm. The curve of Spee then remains essentially unchanged until eruption of the second molars (mean age, 12.38 years), when the depth increases (P < 0.0001) to a mean maximum depth of 2.17 mm. In the adolescent dentition (mean age, 16.21 years), the depth decreases slightly (P = 0.0009) to a mean maximum depth of 1.98 mm, and, in the adult dentition (mean age 26.98 years), the curve remains unchanged (P = 0.66), with a mean maximum depth of 2.02 mm. No significant differences in curve of Spee development were found between
Tan, Bing; Huang, Min; Zhu, Qibing; Guo, Ya; Qin, Jianwei
2017-09-01
The laser induced breakdown spectroscopy (LIBS) technique is an effective method to detect material composition by obtaining the plasma emission spectrum. The overlapping peaks in the spectrum are a fundamental problem in the qualitative and quantitative analysis of LIBS. Based on a curve fitting method, this paper studies an error compensation method to achieve the decomposition and correction of overlapping peaks. The vital step is that the fitting residual is fed back to the overlapping peaks and performs multiple curve fitting processes to obtain a lower residual result. For the quantitative experiments of Cu, the Cu-Fe overlapping peaks in the range of 321-327 nm obtained from the LIBS spectrum of five different concentrations of CuSO 4 ·5H 2 O solution were decomposed and corrected using curve fitting and error compensation methods. Compared with the curve fitting method, the error compensation reduced the fitting residual about 18.12-32.64% and improved the correlation about 0.86-1.82%. Then, the calibration curve between the intensity and concentration of the Cu was established. It can be seen that the error compensation method exhibits a higher linear correlation between the intensity and concentration of Cu, which can be applied to the decomposition and correction of overlapping peaks in the LIBS spectrum.
Quantitative Algebraic Reasoning
DEFF Research Database (Denmark)
Mardare, Radu Iulian; Panangaden, Prakash; Plotkin, Gordon
2016-01-01
We develop a quantitative analogue of equational reasoning which we call quantitative algebra. We deﬁne an equality relation indexed by rationals: a =ε b which we think of as saying that “a is approximately equal to b up to an error of ε”. We have 4 interesting examples where we have a quantitative...... equational theory whose free algebras correspond to well known structures. In each case we have ﬁnitary and continuous versions. The four cases are: Hausdorﬀ metrics from quantitive semilattices; pWasserstein metrics (hence also the Kantorovich metric) from barycentric algebras and also from pointed...
Quantitative autoradiography of neurochemicals
International Nuclear Information System (INIS)
Rainbow, T.C.; Biegon, A.; Bleisch, W.V.
1982-01-01
Several new methods have been developed that apply quantitative autoradiography to neurochemistry. These methods are derived from the 2-deoxyglucose (2DG) technique of Sokoloff (1), which uses quantitative autoradiography to measure the rate of glucose utilization in brain structures. The new methods allow the measurement of the rate of cerbral protein synthesis and the levels of particular neurotransmitter receptors by quantitative autoradiography. As with the 2DG method, the new techniques can measure molecular levels in micron-sized brain structures; and can be used in conjunction with computerized systems of image processing. It is possible that many neurochemical measurements could be made by computerized analysis of quantitative autoradiograms
F(α) curves: Experimental results
International Nuclear Information System (INIS)
Glazier, J.A.; Gunaratne, G.; Libchaber, A.
1988-01-01
We study the transition to chaos at the golden and silver means for forced Rayleigh-Benard (RB) convection in mercury. We present f(α) curves below, at, and above the transition, and provide comparisons to the curves calculated for the one-dimensional circle map. We find good agreement at both the golden and silver means. This confirms our earlier observation that for low amplitude forcing, forced RB convection is well described by the one-dimensional circle map and indicates that the f(α) curve is a good measure of the approach to criticality. For selected subcritical experimental data sets we calculate the degree of subcriticality. We also present both experimental and calculated results for f(α) in the presence of a third frequency. Again we obtain agreement: The presence of random noise or a third frequency narrows the right-hand (negative q) side of the f(α) curve. Subcriticality results in symmetrically narrowed curves. We can also distinguish these cases by examining the power spectra and Poincare sections of the time series
Multiwavelength light curve parameters of Cepheid variables
Directory of Open Access Journals (Sweden)
Bhardwaj Anupam
2017-01-01
Full Text Available We present a comparative analysis of theoretical and observed light curves of Cepheid variables using Fourier decomposition. The theoretical light curves at multiple wavelengths are generated using stellar pulsation models for chemical compositions representative of Cepheids in the Galaxy and Magellanic Clouds. The observed light curves at optical (VI, near-infrared (JHKs and mid-infrared (3.6 & 4.5-μm bands are compiled from the literature. We discuss the variation of light curve parameters as a function of period, wavelength and metallicity. Theoretical and observed Fourier amplitude parameters decrease with increase in wavelength while the phase parameters increase with wavelength. We find that theoretical amplitude parameters obtained using canonical mass-luminosity levels exhibit a greater offset with respect to observations when compared to non-canonical relations. We also discuss the impact of variation in convective efficiency on the light curve structure of Cepheid variables. The increase in mixing length parameter results in a zero-point offset in bolometric mean magnitudes and reduces the systematic large difference in theoretical amplitudes with respect to observations.
Incorporating experience curves in appliance standards analysis
International Nuclear Information System (INIS)
Desroches, Louis-Benoit; Garbesi, Karina; Kantner, Colleen; Van Buskirk, Robert; Yang, Hung-Chia
2013-01-01
There exists considerable evidence that manufacturing costs and consumer prices of residential appliances have decreased in real terms over the last several decades. This phenomenon is generally attributable to manufacturing efficiency gained with cumulative experience producing a certain good, and is modeled by an empirical experience curve. The technical analyses conducted in support of U.S. energy conservation standards for residential appliances and commercial equipment have, until recently, assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. This assumption does not reflect real market price dynamics. Using price data from the Bureau of Labor Statistics, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These experience curves were incorporated into recent energy conservation standards analyses for these products. Including experience curves increases the national consumer net present value of potential standard levels. In some cases a potential standard level exhibits a net benefit when considering experience, whereas without experience it exhibits a net cost. These results highlight the importance of modeling more representative market prices. - Highlights: ► Past appliance standards analyses have assumed constant equipment prices. ► There is considerable evidence of consistent real price declines. ► We incorporate experience curves for several large appliances into the analysis. ► The revised analyses demonstrate larger net present values of potential standards. ► The results imply that past standards analyses may have undervalued benefits.
Comparison of power curve monitoring methods
Directory of Open Access Journals (Sweden)
Cambron Philippe
2017-01-01
Full Text Available Performance monitoring is an important aspect of operating wind farms. This can be done through the power curve monitoring (PCM of wind turbines (WT. In the past years, important work has been conducted on PCM. Various methodologies have been proposed, each one with interesting results. However, it is difficult to compare these methods because they have been developed using their respective data sets. The objective of this actual work is to compare some of the proposed PCM methods using common data sets. The metric used to compare the PCM methods is the time needed to detect a change in the power curve. Two power curve models will be covered to establish the effect the model type has on the monitoring outcomes. Each model was tested with two control charts. Other methodologies and metrics proposed in the literature for power curve monitoring such as areas under the power curve and the use of statistical copulas have also been covered. Results demonstrate that model-based PCM methods are more reliable at the detecting a performance change than other methodologies and that the effectiveness of the control chart depends on the types of shift observed.
Asymptotic scalings of developing curved pipe flow
Ault, Jesse; Chen, Kevin; Stone, Howard
2015-11-01
Asymptotic velocity and pressure scalings are identified for the developing curved pipe flow problem in the limit of small pipe curvature and high Reynolds numbers. The continuity and Navier-Stokes equations in toroidal coordinates are linearized about Dean's analytical curved pipe flow solution (Dean 1927). Applying appropriate scaling arguments to the perturbation pressure and velocity components and taking the limits of small curvature and large Reynolds number yields a set of governing equations and boundary conditions for the perturbations, independent of any Reynolds number and pipe curvature dependence. Direct numerical simulations are used to confirm these scaling arguments. Fully developed straight pipe flow is simulated entering a curved pipe section for a range of Reynolds numbers and pipe-to-curvature radius ratios. The maximum values of the axial and secondary velocity perturbation components along with the maximum value of the pressure perturbation are plotted along the curved pipe section. The results collapse when the scaling arguments are applied. The numerically solved decay of the velocity perturbation is also used to determine the entrance/development lengths for the curved pipe flows, which are shown to scale linearly with the Reynolds number.
Critical Factors for Inducing Curved Somatosensory Saccades
Directory of Open Access Journals (Sweden)
Tamami Nakano
2011-10-01
Full Text Available We are able to make a saccade toward a tactile stimuli to one hand, but trajectories of many saccades curved markedly when the arms were crossed (Groh & Sparks, 2006. However, it remains unknown why some curved and others did not. We therefore examined critical factors for inducing the curved somatosensory saccades. Participants made a saccade as soon as possible from a central fixation point toward a tactile stimulus delivered to one of the two hands, and switched between arms-crossed and arms-uncrossed postures every 6 trials. Trajectories were generally straight when the arms were uncrossed, but all participants made curved saccades when the arms were crossed (12–64%. We found that the probability of curved saccades depended critically on the onset latency: the probability was less than 5% when the latency was larger than 250 ms, but the probability increased up to 70–80% when the onset latency was 160 ms. This relationship was shared across participants. The results suggest that a touch in the arms-crossed posture was always mapped to the wrong hand in the initial phase up to 160 ms, and then remapped to the correct hand during the next 100 ms by some fundamental neural mechanisms shared across participants.
TYPE Ia SUPERNOVA LIGHT-CURVE INFERENCE: HIERARCHICAL BAYESIAN ANALYSIS IN THE NEAR-INFRARED
International Nuclear Information System (INIS)
Mandel, Kaisey S.; Friedman, Andrew S.; Kirshner, Robert P.; Wood-Vasey, W. Michael
2009-01-01
We present a comprehensive statistical analysis of the properties of Type Ia supernova (SN Ia) light curves in the near-infrared using recent data from Peters Automated InfraRed Imaging TELescope and the literature. We construct a hierarchical Bayesian framework, incorporating several uncertainties including photometric error, peculiar velocities, dust extinction, and intrinsic variations, for principled and coherent statistical inference. SN Ia light-curve inferences are drawn from the global posterior probability of parameters describing both individual supernovae and the population conditioned on the entire SN Ia NIR data set. The logical structure of the hierarchical model is represented by a directed acyclic graph. Fully Bayesian analysis of the model and data is enabled by an efficient Markov Chain Monte Carlo algorithm exploiting the conditional probabilistic structure using Gibbs sampling. We apply this framework to the JHK s SN Ia light-curve data. A new light-curve model captures the observed J-band light-curve shape variations. The marginal intrinsic variances in peak absolute magnitudes are σ(M J ) = 0.17 ± 0.03, σ(M H ) = 0.11 ± 0.03, and σ(M Ks ) = 0.19 ± 0.04. We describe the first quantitative evidence for correlations between the NIR absolute magnitudes and J-band light-curve shapes, and demonstrate their utility for distance estimation. The average residual in the Hubble diagram for the training set SNe at cz > 2000kms -1 is 0.10 mag. The new application of bootstrap cross-validation to SN Ia light-curve inference tests the sensitivity of the statistical model fit to the finite sample and estimates the prediction error at 0.15 mag. These results demonstrate that SN Ia NIR light curves are as effective as corrected optical light curves, and, because they are less vulnerable to dust absorption, they have great potential as precise and accurate cosmological distance indicators.
He, Shiyuan; Wang, Lifan; Huang, Jianhua Z.
2018-04-01
With growing data from ongoing and future supernova surveys, it is possible to empirically quantify the shapes of SNIa light curves in more detail, and to quantitatively relate the shape parameters with the intrinsic properties of SNIa. Building such relationships is critical in controlling systematic errors associated with supernova cosmology. Based on a collection of well-observed SNIa samples accumulated in the past years, we construct an empirical SNIa light curve model using a statistical method called the functional principal component analysis (FPCA) for sparse and irregularly sampled functional data. Using this method, the entire light curve of an SNIa is represented by a linear combination of principal component functions, and the SNIa is represented by a few numbers called “principal component scores.” These scores are used to establish relations between light curve shapes and physical quantities such as intrinsic color, interstellar dust reddening, spectral line strength, and spectral classes. These relations allow for descriptions of some critical physical quantities based purely on light curve shape parameters. Our study shows that some important spectral feature information is being encoded in the broad band light curves; for instance, we find that the light curve shapes are correlated with the velocity and velocity gradient of the Si II λ6355 line. This is important for supernova surveys (e.g., LSST and WFIRST). Moreover, the FPCA light curve model is used to construct the entire light curve shape, which in turn is used in a functional linear form to adjust intrinsic luminosity when fitting distance models.
Belhi, Memdouh; Han, Jie; Casey, Tiernan A.; Chen, Jyh-Yuan; Im, Hong G.; Sarathy, S. Mani; Bisetti, Fabrizio
2018-01-01
Current-voltage, or i–V, curves are used in combustion to characterise the ionic structure of flames. The objective of this paper is to develop a detailed modelling framework for the quantitative prediction of the i–V curves in methane/air flames
Surface growth kinematics via local curve evolution
Moulton, Derek E.
2012-11-18
A mathematical framework is developed to model the kinematics of surface growth for objects that can be generated by evolving a curve in space, such as seashells and horns. Growth is dictated by a growth velocity vector field defined at every point on a generating curve. A local orthonormal basis is attached to each point of the generating curve and the velocity field is given in terms of the local coordinate directions, leading to a fully local and elegant mathematical structure. Several examples of increasing complexity are provided, and we demonstrate how biologically relevant structures such as logarithmic shells and horns emerge as analytical solutions of the kinematics equations with a small number of parameters that can be linked to the underlying growth process. Direct access to cell tracks and local orientation enables for connections to be made to the underlying growth process. © 2012 Springer-Verlag Berlin Heidelberg.
Asymmetry dependence of the nuclear caloric curve
International Nuclear Information System (INIS)
McIntosh, A.B.; Bonasera, A.; Cammarata, P.; Hagel, K.; Heilborn, L.; Kohley, Z.; Mabiala, J.; May, L.W.; Marini, P.; Raphelt, A.; Souliotis, G.A.; Wuenschel, S.; Zarrella, A.; Yennello, S.J.
2013-01-01
A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron–proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A=50. The caloric curve extracted with the momentum quadrupole fluctuation thermometer shows that the temperature varies linearly with quasi-projectile asymmetry (N−Z)/A . An increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei
The genus curve of the Abell clusters
Rhoads, James E.; Gott, J. Richard, III; Postman, Marc
1994-01-01
We study the topology of large-scale structure through a genus curve measurement of the recent Abell catalog redshift survey of Postman, Huchra, and Geller (1992). The structure is found to be spongelike near median density and to exhibit isolated superclusters and voids at high and low densities, respectively. The genus curve shows a slight shift toward 'meatball' topology, but remains consistent with the hypothesis of Gaussian random phase initial conditions. The amplitude of the genus curve corresponds to a power-law spectrum with index n = 0.21-0.47+0.43 on scales of 48/h Mpc or to a cold dark matter power spectrum with omega h = 0.36-0.17+0.46.
Differential geometry of curves and surfaces
Banchoff, Thomas F
2010-01-01
Students and professors of an undergraduate course in differential geometry will appreciate the clear exposition and comprehensive exercises in this book that focuses on the geometric properties of curves and surfaces, one- and two-dimensional objects in Euclidean space. The problems generally relate to questions of local properties (the properties observed at a point on the curve or surface) or global properties (the properties of the object as a whole). Some of the more interesting theorems explore relationships between local and global properties. A special feature is the availability of accompanying online interactive java applets coordinated with each section. The applets allow students to investigate and manipulate curves and surfaces to develop intuition and to help analyze geometric phenomena.
Experimental simulation of closed timelike curves.
Ringbauer, Martin; Broome, Matthew A; Myers, Casey R; White, Andrew G; Ralph, Timothy C
2014-06-19
Closed timelike curves are among the most controversial features of modern physics. As legitimate solutions to Einstein's field equations, they allow for time travel, which instinctively seems paradoxical. However, in the quantum regime these paradoxes can be resolved, leaving closed timelike curves consistent with relativity. The study of these systems therefore provides valuable insight into nonlinearities and the emergence of causal structures in quantum mechanics--essential for any formulation of a quantum theory of gravity. Here we experimentally simulate the nonlinear behaviour of a qubit interacting unitarily with an older version of itself, addressing some of the fascinating effects that arise in systems traversing a closed timelike curve. These include perfect discrimination of non-orthogonal states and, most intriguingly, the ability to distinguish nominally equivalent ways of preparing pure quantum states. Finally, we examine the dependence of these effects on the initial qubit state, the form of the unitary interaction and the influence of decoherence.
Design fatigue curve for Hastelloy-X
International Nuclear Information System (INIS)
Nishiguchi, Isoharu; Muto, Yasushi; Tsuji, Hirokazu
1983-12-01
In the design of components intended for elevated temperature service as the experimental Very High-Temperature gas-cooled Reactor (VHTR), it is essential to prevent fatigue failure and creep-fatigue failure. The evaluation method which uses design fatigue curves is adopted in the design rules. This report discussed several aspects of these design fatigue curves for Hastelloy-X (-XR) which is considered for use as a heat-resistant alloy in the VHTR. Examination of fatigue data gathered by a literature search including unpublished data showed that Brinkman's equation is suitable for the design curve of Hastelloy-X (-XR), where total strain range Δ epsilon sub(t) is used as independent variable and fatigue life Nsub(f) is transformed into log(log Nsub(f)). (author)
The genus curve of the Abell clusters
Rhoads, James E.; Gott, J. Richard, III; Postman, Marc
1994-01-01
We study the topology of large-scale structure through a genus curve measurement of the recent Abell catalog redshift survey of Postman, Huchra, and Geller (1992). The structure is found to be spongelike near median density and to exhibit isolated superclusters and voids at high and low densities, respectively. The genus curve shows a slight shift toward 'meatball' topology, but remains consistent with the hypothesis of Gaussian random phase initial conditions. The amplitude of the genus curve corresponds to a power-law spectrum with index n = 0.21(sub -0.47 sup +0.43) on scales of 48/h Mpc or to a cold dark matter power spectrum with omega h = 0.36(sub -0.17 sup +0.46).
Deep-learnt classification of light curves
DEFF Research Database (Denmark)
Mahabal, Ashish; Gieseke, Fabian; Pai, Akshay Sadananda Uppinakudru
2017-01-01
is to derive statistical features from the time series and to use machine learning methods, generally supervised, to separate objects into a few of the standard classes. In this work, we transform the time series to two-dimensional light curve representations in order to classify them using modern deep......Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and techniques to classify light curves. A common approach...... learning techniques. In particular, we show that convolutional neural networks based classifiers work well for broad characterization and classification. We use labeled datasets of periodic variables from CRTS survey and show how this opens doors for a quick classification of diverse classes with several...
Energy efficiency and load curve impacts
International Nuclear Information System (INIS)
Feilberg, Nicolai
2002-01-01
One of SINTEF Energy Research's European RTD projects is the two-year EFFLOCOM (Energy EFFiciency and LOad curve impacts of COMmercial development in competitive markets). This project will determine the end-user response of different market-related services offered in deregulated power markets. The project will investigate the possibility of influencing load curves by using different price signals and two-way communications via Internet. The partners are from Denmark. Finland, England, France and Norway. SINTEF Energy Research is in charge of the project management. During the project, the changes in load curves will he studied in the in the participating countries before and after deregulation. Specific issues are the use of ICT, time- and situation-dependent tariffs and smart-house technology. The project will consist of 5 work packages that will give recommendations about new methods, guidelines and tools to promote effective use of energy in the partner countries. The total budget is EUR 692 000. (author)
Trend curve data development and testing
International Nuclear Information System (INIS)
McElroy, W.N.; Gold, R.; Simons, R.L.; Roberts, J.H.
1986-01-01
Existing trend curves do not account for previous and more recently observed test and power reactor flux-level, thermal neutron and γ-ray field-induced effects. Any agreement between measured data and trend curve predictions that does not adequately represent the important neutron environmental and temperature effects as well as the microstructural damage processes, therefore, could be fortuitous. Empirically derived end-of-life (EOL) and life-extension-range (LER) trend curves are presented and discussed in this paper for high temperature [∼288 0 C (550 0 F)] irradiation of two weld, two plate, and two forging pressure vessel (PV) steels and low-temperature [∼60 0 C (140 0 F)] irradiation of one support structure-type steel
Minimal families of curves on surfaces
Lubbes, Niels
2014-11-01
A minimal family of curves on an embedded surface is defined as a 1-dimensional family of rational curves of minimal degree, which cover the surface. We classify such minimal families using constructive methods. This allows us to compute the minimal families of a given surface.The classification of minimal families of curves can be reduced to the classification of minimal families which cover weak Del Pezzo surfaces. We classify the minimal families of weak Del Pezzo surfaces and present a table with the number of minimal families of each weak Del Pezzo surface up to Weyl equivalence.As an application of this classification we generalize some results of Schicho. We classify algebraic surfaces that carry a family of conics. We determine the minimal lexicographic degree for the parametrization of a surface that carries at least 2 minimal families. © 2014 Elsevier B.V.
Energy and GHG abatement cost curves
Energy Technology Data Exchange (ETDEWEB)
Alvarenga, Rafael [BHP Billiton Base Metals (Australia)
2010-07-01
Global warming due to various reasons but especially to emission of green house gases (GHGs) has become a cause for serious concern. This paper discusses the steps taken by BHP Billiton to reduce energy consumption and GHG emissions using cost curves. According to forecasts, global warming is expected to impact Chile badly and the rise in temperature could be between 1 and more than 5 degrees Celsius. Mining in Chile consumes a lot of energy, particularly electricity. Total energy and electricity consumption in 2007 was 13 and 36 % respectively. BHP base metals developed a set of abatement cost curves for energy and GHG in Chile and these are shown in figures. The methodology for the curves consisted of consultant visits to each mine operation. The study also includes mass energy balance and feasibility maps. The paper concludes that it is important to evaluate the potential for reducing emissions and energy and their associated costs.
National Research Council Canada - National Science Library
Narusawa, Uichiro
2003-01-01
.... A mechanistic model of the total respiratory system is developed for the inflation process, relating characteristics of the p-V model equation to the internal respiratory conditions such as alveolar...
Autoshaped Head Poking in the Mouse: A Quantitative Analysis of the Learning Curve
Papachristos, Efstathios B.; Gallistel, C. R.
2006-01-01
In autoshaping experiments, we quantified the acquisition of anticipatory head poking in individual mice, using an algorithm that finds changes in the slope of a cumulative record. In most mice, upward changes in the amount of anticipatory poking per trial were abrupt, and tended to occur at session boundaries, suggesting that the session is as…
POSSIBLE RECESSION CURVE APPLICATIONS FOR RETENTION EVALUATION
Directory of Open Access Journals (Sweden)
Daniel Liberacki
2015-11-01
Full Text Available The objective of the article was to present possible applications of recession flow curve in a small lowland watershed retention discharge size evaluation. The examined woodland micro catchment area of 0.52 sq km is located in Puszcza Zielonka in central Wielkopolska. The Hutka catchment is typically woody with high retention abilities. The catchment of the Hutka watercourse is forested in 89%, the other 11% is covered by swamps and wasteland. The predominant sites are fresh mixed coniferous forest (BMśw, fresh coniferous forest (Bśw and alder carr forest (Ol. Landscape in catchment is characterized by a large number of interior depressions, filled partly with rainwater or peatbogs, with poorly developed natural drainage. The watercourses do not exceed 1 km in length, the mean width is approx. 0.5 m, while mean depth ranges from 0.2 to 0.3 m. During hydrological research conducted in 1997/1998–1999/2000, 35 major (characteristic raised water stages were observed in Hutka after substantial precipitation. The recession curve dating from 18–24 September 2000 has the α and n rates nearest to average. Comparing the model curve and the curve created by observing watercourse flow, one can notice their resemblance and that they have similar ordinate values as well as shape. In the case of other recession curves, the maximum differences of ordinate values are also about 0.1–0.2 l/s/km2. The measuured α and n rates do not reveal any regularities. There are no significant statistical Horton model parameter (for recession flow curves dependencies between α and n and e.g. initial flows (Qo or the whole period of high water waves (Qp. Consequently, calculated relation between these parameters is only an approximation for the general evaluation of the retention discharge in the catchment area towards retention with flow function.
Fractal properties of critical invariant curves
International Nuclear Information System (INIS)
Hunt, B.R.; Yorke, J.A.; Khanin, K.M.; Sinai, Y.G.
1996-01-01
We examine the dimension of the invariant measure for some singular circle homeomorphisms for a variety of rotation numbers, through both the thermodynamic formalism and numerical computation. The maps we consider include those induced by the action of the standard map on an invariant curve at the critical parameter value beyond which the curve is destroyed. Our results indicate that the dimension is universal for a given type of singularity and rotation number, and that among all rotation numbers, the golden mean produces the largest dimension
Trend curve data development and testing
International Nuclear Information System (INIS)
McElroy, W.N.; Gold, R.; Simons, R.L.; Roberts, J.H.
1986-08-01
Existing trend curves do not account for previous and more recently observed test and power reactor flux-level, thermal neutron and gamma-ray field-induced effects. Any agreement between measured data and trend curve predictions that does not adequately represent the important neutron environmental and temperature effects as well as the microstructural damage processes, therefore, could be fortuitous. Two principal questions asked concerning the metallurgical condition of the pressure vessel and its support structures are: What are the controlling variables; and What effects do they have on changing the metallurgical properties of the vessel and its support structures throughout their lifetimes
Linear Titration Curves of Acids and Bases.
Joseph, N R
1959-05-29
The Henderson-Hasselbalch equation, by a simple transformation, becomes pH - pK = pA - pB, where pA and pB are the negative logarithms of acid and base concentrations. Sigmoid titration curves then reduce to straight lines; titration curves of polyelectrolytes, to families of straight lines. The method is applied to the titration of the dipeptide glycyl aminotricarballylic acid, with four titrable groups. Results are expressed as Cartesian and d'Ocagne nomograms. The latter is of a general form applicable to polyelectrolytes of any degree of complexity.
From Curve Fitting to Machine Learning
Zielesny, Achim
2011-01-01
The analysis of experimental data is at heart of science from its beginnings. But it was the advent of digital computers that allowed the execution of highly non-linear and increasingly complex data analysis procedures - methods that were completely unfeasible before. Non-linear curve fitting, clustering and machine learning belong to these modern techniques which are a further step towards computational intelligence. The goal of this book is to provide an interactive and illustrative guide to these topics. It concentrates on the road from two dimensional curve fitting to multidimensional clus
Phonon dispersion curves for CsCN
International Nuclear Information System (INIS)
Gaur, N.K.; Singh, Preeti; Rini, E.G.; Galgale, Jyostna; Singh, R.K.
2004-01-01
The motivation for the present work was gained from the recent publication on phonon dispersion curves (PDCs) of CsCN from the neutron scattering technique. We have applied the extended three-body force shell model (ETSM) by incorporating the effect of coupling between the translation modes and the orientation of cyanide molecules for the description of phonon dispersion curves of CsCN between the temperatures 195 and 295 K. Our results on PDCs in symmetric direction are in good agreement with the experimental data measured with inelastic neutron scattering technique. (author)
Bound states in curved quantum waveguides
International Nuclear Information System (INIS)
Exner, P.; Seba, P.
1987-01-01
We study free quantum particle living on a curved planar strip Ω of a fixed width d with Dirichlet boundary conditions. It can serve as a model for electrons in thin films on a cylindrical-type substrate, or in a curved quantum wire. Assuming that the boundary of Ω is infinitely smooth and its curvature decays fast enough at infinity, we prove that a bound state with energy below the first transversal mode exists for all sufficiently small d. A lower bound on the critical width is obtained using the Birman-Schwinger technique. (orig.)
Strange Curves, Counting Rabbits, & Other Mathematical Explorations
Ball, Keith
2011-01-01
How does mathematics enable us to send pictures from space back to Earth? Where does the bell-shaped curve come from? Why do you need only 23 people in a room for a 50/50 chance of two of them sharing the same birthday? In Strange Curves, Counting Rabbits, and Other Mathematical Explorations, Keith Ball highlights how ideas, mostly from pure math, can answer these questions and many more. Drawing on areas of mathematics from probability theory, number theory, and geometry, he explores a wide range of concepts, some more light-hearted, others central to the development of the field and used dai
Boiling curve in high quality flow boiling
International Nuclear Information System (INIS)
Shiralkar, B.S.; Hein, R.A.; Yadigaroglu, G.
1980-01-01
The post dry-out heat transfer regime of the flow boiling curve was investigated experimentally for high pressure water at high qualities. The test section was a short round tube located downstream of a hot patch created by a temperature controlled segment of tubing. Results from the experiment showed that the distance from the dryout point has a significant effect on the downstream temperatures and there was no unique boiling curve. The heat transfer coefficients measured sufficiently downstream of the dryout point could be correlated using the Heineman correlation for superheated steam, indicating that the droplet deposition effects could be neglected in this region
Light Curve Analysis of SAO23229
Directory of Open Access Journals (Sweden)
Ho-Il Kim
1993-06-01
Full Text Available We have made UBV light curves of a newly discovered eclipsing binary, SAO23229 at Sobaeksan Astronomy Observatory. We determined a minimum light time of HJD2448636.1170+/-0.0005 that is 3 minutes later than predicted time, and founda peculiar light variation at phase 0.75 that may not be secondary eclipse. Orbital period of SAO23229 would be 4.2 days rather than 2.1 days. Our analysis of the light curves shows that SAO23229 has a detached configuration consisting of two almost identical F type main sequence stars.
Frozen history : limitations and possibilities of quantitative diffusion studies
Mom, G.P.A.; Albert de la Bruhèze, A.A.; Oldenziel, R.
2009-01-01
In this contribution I have tried to show how quantitative methods can generate new questions and thus support historical research. It can be concluded that re ducing historical complexity through forcing reality into the shape of a diffusion curve does not seem to be the preferable strategy for
a new approach of Analysing GRB light curves
International Nuclear Information System (INIS)
Varga, B.; Horvath, I.
2005-01-01
We estimated the T xx quantiles of the cumulative GRB light curves using our recalculated background. The basic information of the light curves was extracted by multivariate statistical methods. The possible classes of the light curves are also briefly discussed
Bijlsma, S.; Boelens, H. F. M.; Hoefsloot, H. C. J.; Smilde, A. K.
2000-01-01
A traditional curve fitting (TCF) algorithm is compared with a classical curve resolution (CCR) approach for estimating reaction rate constants from spectral data obtained in time of a chemical reaction. In the TCF algorithm, reaction rate constants an estimated from the absorbance versus time data
In-Vehicle Dynamic Curve-Speed Warnings at High-Risk Rural Curves
2018-03-01
Lane-departure crashes at horizontal curves represent a significant portion of fatal crashes on rural Minnesota roads. Because of this, solutions are needed to aid drivers in identifying upcoming curves and inform them of a safe speed at which they s...
Modeling of Continuum Manipulators Using Pythagorean Hodograph Curves.
Singh, Inderjeet; Amara, Yacine; Melingui, Achille; Mani Pathak, Pushparaj; Merzouki, Rochdi
2018-05-10
Research on continuum manipulators is increasingly developing in the context of bionic robotics because of their many advantages over conventional rigid manipulators. Due to their soft structure, they have inherent flexibility, which makes it a huge challenge to control them with high performances. Before elaborating a control strategy of such robots, it is essential to reconstruct first the behavior of the robot through development of an approximate behavioral model. This can be kinematic or dynamic depending on the conditions of operation of the robot itself. Kinematically, two types of modeling methods exist to describe the robot behavior; quantitative methods describe a model-based method, and qualitative methods describe a learning-based method. In kinematic modeling of continuum manipulator, the assumption of constant curvature is often considered to simplify the model formulation. In this work, a quantitative modeling method is proposed, based on the Pythagorean hodograph (PH) curves. The aim is to obtain a three-dimensional reconstruction of the shape of the continuum manipulator with variable curvature, allowing the calculation of its inverse kinematic model (IKM). It is noticed that the performances of the PH-based kinematic modeling of continuum manipulators are considerable regarding position accuracy, shape reconstruction, and time/cost of the model calculation, than other kinematic modeling methods, for two cases: free load manipulation and variable load manipulation. This modeling method is applied to the compact bionic handling assistant (CBHA) manipulator for validation. The results are compared with other IKMs developed in case of CBHA manipulator.
International Nuclear Information System (INIS)
Yamazaki, Tadashi; Suzuki, Jun-ichi; Shimamoto, Ryoichi; Tsuji, Taeko; Ohmoto-Sekine, Yuki; Morita, Toshihiro; Yamashita, Hiroshi; Honye, Junko; Nagai, Ryozo; Komatsu, Shuhei; Akahane, Masaaki; Ohtomo, Kuni
2008-01-01
Purpose: Hounsfield CT values across coronary CT angiograms constitute CT value-spatial profile curves. These CT profile curves are independent of window settings, and therefore, parameters derived from the curves can be used for objective anatomic analyses. Applicability of parameters derived from the curves to quantification of coronary in-stent patency has not yet been evaluated. Methods: Twenty-five CT value-spatial profile curves were delineated from 10 consecutive coronary stents to test correlation between the curve derived parameter (i.e., the minimum extreme value normalized by dividing by the maximum value of the curves obtained at neighboring outside of stents) and three intravascular ultrasound (IVUS) parameters. Results: Correlation coefficients between normalized minimum extreme value of CT value-spatial profile curves and three IVUS parameters (such as patent cross-sectional in-stent area, the percentage of patent cross-sectional in-stent area, and coronary artery intra-stent diameter) were 0.65 (p < 0.01), 0.44 (p < 0.05) and 0.51 (p < 0.05), respectively. Conclusions: CT parameters defined on Hounsfield CT value-spatial profile curves correlated significantly with IVUS parameters for quantitative coronary in-stent patency. A new approach with CT coronary angiography is therefore indicated for the noninvasive assessment of in-stent re-stenosis
Matter fields in curved space-time
International Nuclear Information System (INIS)
Viet, Nguyen Ai; Wali, Kameshwar C.
2000-01-01
We study the geometry of a two-sheeted space-time within the framework of non-commutative geometry. As a prelude to the Standard Model in curved space-time, we present a model of a left- and a right- chiral field living on the two sheeted-space time and construct the action functionals that describe their interactions
Some genus 3 curves with many points
Auer, R; Top, J; Fieker, C; Kohel, DR
2002-01-01
We explain a naive approach towards the problem of finding genus 3 curves C over any given finite field F-q of odd characteristic, with a number of rational points close to the Hasse-Weil-Serre upper bound q+1+3[2rootq]. The method turns out to be successful at least in characteristic 3.
PV experience curves for the Netherlands
International Nuclear Information System (INIS)
Gerwig, R.
2005-01-01
Experience curves are one of several tools used by policy makers to take a look at market development. Numerous curves have been constructed for PV but none specific to the Netherlands. The objective of this report is to take a look at the price development of grid-connected PV systems in the Netherlands using the experience curve theory. After a literature and internet search and attempts to acquire information from PV companies information on 51% of the totally installed capacity was found. Curves for the period 1991-2001 were constructed based on system price, BOS (balance-of-system) price and inverter price. The progress ratio of the locally learning BOS was similar to the globally learning module market. This indicates that the pace of development of the Dutch PV market is similar to the globally followed pace. Improvement of the detail of the data might help to get a better idea of which BOS components have declined most. The similar progress ratio also shows the importance of investing both in module and system research as is the case in the Netherlands
Bootstrap confidence intervals for principal response curves
Timmerman, Marieke E.; Ter Braak, Cajo J. F.
2008-01-01
The principal response curve (PRC) model is of use to analyse multivariate data resulting from experiments involving repeated sampling in time. The time-dependent treatment effects are represented by PRCs, which are functional in nature. The sample PRCs can be estimated using a raw approach, or the
Bootstrap Confidence Intervals for Principal Response Curves
Timmerman, M.E.; Braak, ter C.J.F.
2008-01-01
The principal response curve (PRC) model is of use to analyse multivariate data resulting from experiments involving repeated sampling in time. The time-dependent treatment effects are represented by PRCs, which are functional in nature. The sample PRCs can be estimated using a raw approach, or the
Light extraction block with curved surface
Levermore, Peter; Krall, Emory; Silvernail, Jeffrey; Rajan, Kamala; Brown, Julia J.
2016-03-22
Light extraction blocks, and OLED lighting panels using light extraction blocks, are described, in which the light extraction blocks include various curved shapes that provide improved light extraction properties compared to parallel emissive surface, and a thinner form factor and better light extraction than a hemisphere. Lighting systems described herein may include a light source with an OLED panel. A light extraction block with a three-dimensional light emitting surface may be optically coupled to the light source. The three-dimensional light emitting surface of the block may includes a substantially curved surface, with further characteristics related to the curvature of the surface at given points. A first radius of curvature corresponding to a maximum principal curvature k.sub.1 at a point p on the substantially curved surface may be greater than a maximum height of the light extraction block. A maximum height of the light extraction block may be less than 50% of a maximum width of the light extraction block. Surfaces with cross sections made up of line segments and inflection points may also be fit to approximated curves for calculating the radius of curvature.
Spherical images and inextensible curved folding
Seffen, Keith A.
2018-02-01
In their study, Duncan and Duncan [Proc. R. Soc. London A 383, 191 (1982), 10.1098/rspa.1982.0126] calculate the shape of an inextensible surface folded in two about a general curve. They find the analytical relationships between pairs of generators linked across the fold curve, the shape of the original path, and the fold angle variation along it. They present two special cases of generator layouts for which the fold angle is uniform or the folded curve remains planar, for simplifying practical folding in sheet-metal processes. We verify their special cases by a graphical treatment according to a method of Gauss. We replace the fold curve by a piecewise linear path, which connects vertices of intersecting pairs of hinge lines. Inspired by the d-cone analysis by Farmer and Calladine [Int. J. Mech. Sci. 47, 509 (2005), 10.1016/j.ijmecsci.2005.02.013], we construct the spherical images for developable folding of successive vertices: the operating conditions of the special cases in Duncan and Duncan are then revealed straightforwardly by the geometric relationships between the images. Our approach may be used to synthesize folding patterns for novel deployable and shape-changing surfaces without need of complex calculation.
Principal normal indicatrices of closed space curves
DEFF Research Database (Denmark)
Røgen, Peter
1999-01-01
A theorem due to J. Weiner, which is also proven by B. Solomon, implies that a principal normal indicatrix of a closed space curve with nonvanishing curvature has integrated geodesic curvature zero and contains no subarc with integrated geodesic curvature pi. We prove that the inverse problem alw...
Steady turbulent flow in curved rectangular channels
De Vriend, H.J.
1979-01-01
After the study of fully developed and developing steady laminar flow in curved channels of shallow rectangular wet cross-section (see earlier reports in this series), steady turbulent flow in such channels is investigated as a next step towards a mathematical model of the flow in shallow river
ATLAS detector records its first curved muon
2007-01-01
The barrel muon spectrometer of the ATLAS detector has acquired its first cosmic event in a magnetic field produced by the barrel toroid magnet. This was an important test of the chambers in their final configurations, and marked the first triggering and measurement of curved cosmic ray muons in ATLAS.
Dual kinetic curves in reversible electrochemical systems.
Directory of Open Access Journals (Sweden)
Michael J Hankins
Full Text Available We introduce dual kinetic chronoamperometry, in which reciprocal relations are established between the kinetic curves of electrochemical reactions that start from symmetrical initial conditions. We have performed numerical and experimental studies in which the kinetic curves of the electron-transfer processes are analyzed for a reversible first order reaction. Experimental tests were done with the ferrocyanide/ferricyanide system in which the concentrations of each component could be measured separately using the platinum disk/gold ring electrode. It is shown that the proper ratio of the transient kinetic curves obtained from cathodic and anodic mass transfer limited regions give thermodynamic time invariances related to the reaction quotient of the bulk concentrations. Therefore, thermodynamic time invariances can be observed at any time using the dual kinetic curves for reversible reactions. The technique provides a unique possibility to extract the non-steady state trajectory starting from one initial condition based only on the equilibrium constant and the trajectory which starts from the symmetrical initial condition. The results could impact battery technology by predicting the concentrations and currents of the underlying non-steady state processes in a wide domain from thermodynamic principles and limited kinetic information.
Remote sensing used for power curves
DEFF Research Database (Denmark)
Wagner, Rozenn; Ejsing Jørgensen, Hans; Schmidt Paulsen, Uwe
2008-01-01
Power curve measurement for large wind turbines requires taking into account more parameters than only the wind speed at hub height. Based on results from aerodynamic simulations, an equivalent wind speed taking the wind shear into account was defined and found to reduce the power standard deviat...
Asymptotic Translation Length in the Curve Complex
Valdivia, Aaron D.
2013-01-01
We show that when the genus and punctures of a surface are directly proportional by some rational number the minimal asymptotic translation length in the curve complex has behavior inverse to the square of the Euler characteristic. We also show that when the genus is fixed and the number of punctures varies the behavior is inverse to the Euler characteristic.
Strong imploding shock, the representative curve
International Nuclear Information System (INIS)
Mishkin, E.A.; Alejaldre, C.
1981-01-01
The representative curve of the ideal gas behind the front of a spherically, or cylindrically, symmetric strong imploding shock is shown to pass through the point where the reduced pressure is maximum, P(xisub(m)) = Psub(m)sub(a)sub(x). (orig.)
Focus on Physics: The Delightful Catenary Curve
Hewitt, Paul G.
2017-01-01
When teaching how "tension" and "compression" relate to geometrical structures such as bridges, arches, and domes, The author shows a picture of the Notre Dame Cathedral in Paris, completed in the 14th century, and presents a lesson on using the curve called a catenary to explain how he teaches about tension and compression…
Nonlinear Growth Curves in Developmental Research
Grimm, Kevin J.; Ram, Nilam; Hamagami, Fumiaki
2011-01-01
Developmentalists are often interested in understanding change processes, and growth models are the most common analytic tool for examining such processes. Nonlinear growth curves are especially valuable to developmentalists because the defining characteristics of the growth process such as initial levels, rates of change during growth spurts, and…
Residual Structures in Latent Growth Curve Modeling
Grimm, Kevin J.; Widaman, Keith F.
2010-01-01
Several alternatives are available for specifying the residual structure in latent growth curve modeling. Two specifications involve uncorrelated residuals and represent the most commonly used residual structures. The first, building on repeated measures analysis of variance and common specifications in multilevel models, forces residual variances…
Updated Hubbert curves analyze world oil supply
International Nuclear Information System (INIS)
Ivanhoe, L.F.
1996-01-01
The question is not whether, but when, world crude oil production will start to decline, ushering in the permanent oil shock era. While global information for predicting this event is not so straightforward as the data M. King Hubbert used in creating his famous Hubbert Curve that predicted the US (Lower 48 states, or US/48) 1970 oil production peak, there are strong indications that most of the world's large exploration targets have now been found. Meanwhile, the earth's population is exploding along with the oil needs of Asia's developing nations. This article reviews Hubbert's original analyses on oil discovery and production curves for the US/48 and projects his proven methodology onto global oil discoveries and production as of 1992. The world's oil discovery curve peaked in 1962, and thence declined, as a Hubbert Curve predicts. However, global production was restricted after the 1973 Arab oil embargo. Otherwise, world production would have peaked in the mid-1990s. Two graphs show alternate versions of future global oil production
Growth Curves for Girls with Turner Syndrome
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Fabio Bertapelli
2014-01-01
Full Text Available The objective of this study was to review the growth curves for Turner syndrome, evaluate the methodological and statistical quality, and suggest potential growth curves for clinical practice guidelines. The search was carried out in the databases Medline and Embase. Of 1006 references identified, 15 were included. Studies constructed curves for weight, height, weight/height, body mass index, head circumference, height velocity, leg length, and sitting height. The sample ranged between 47 and 1,565 (total = 6,273 girls aged 0 to 24 y, born between 1950 and 2006. The number of measures ranged from 580 to 9,011 (total = 28,915. Most studies showed strengths such as sample size, exclusion of the use of growth hormone and androgen, and analysis of confounding variables. However, the growth curves were restricted to height, lack of information about selection bias, limited distributional properties, and smoothing aspects. In conclusion, we observe the need to construct an international growth reference for girls with Turner syndrome, in order to provide support for clinical practice guidelines.
Sound concentration caused by curved surfaces
Vercammen, M.L.S.
2012-01-01
In room acoustics the focusing effect of reflections from concave surfaces is a wellknown problem. Although curved surfaces are found throughout the history of architecture, the occurrence of concave surfaces has tended to increase in modern architecture, due to new techniques in design, materials
Singular interactions supported by embedded curves
International Nuclear Information System (INIS)
Kaynak, Burak Tevfik; Turgut, O Teoman
2012-01-01
In this work, singular interactions supported by embedded curves on Riemannian manifolds are discussed from a more direct and physical perspective, via the heat kernel approach. We show that the renormalized problem is well defined, the ground state is finite and the corresponding wavefunction is positive. The renormalization group invariance of the model is also discussed. (paper)
Theoretical Magnon Dispersion Curves for Gd
DEFF Research Database (Denmark)
Lindgård, Per-Anker; Harmon, B. N.; Freeman, A. J.
1975-01-01
The magnon dispersion curve of Gd metal has been determined from first principles by use of augmented-plane-wave energy bands and wave functions. The exchange matrix elements I(k⃗, k⃗′) between the 4f electrons and the conduction electrons from the first six energy bands were calculated under...
A Probabilistic Framework for Curve Evolution
DEFF Research Database (Denmark)
Dahl, Vedrana Andersen
2017-01-01
approach include ability to handle textured images, simple generalization to multiple regions, and efficiency in computation. We test our probabilistic framework in combination with parametric (snakes) and geometric (level-sets) curves. The experimental results on composed and natural images demonstrate...
Covariant quantizations in plane and curved spaces
International Nuclear Information System (INIS)
Assirati, J.L.M.; Gitman, D.M.
2017-01-01
We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)
Covariant quantizations in plane and curved spaces
Energy Technology Data Exchange (ETDEWEB)
Assirati, J.L.M. [University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Gitman, D.M. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); P.N. Lebedev Physical Institute, Moscow (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil)
2017-07-15
We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)
Numerical analysis of thermoluminescence glow curves
International Nuclear Information System (INIS)
Gomez Ros, J. M.; Delgado, A.
1989-01-01
This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs
Irregularities in the dendrochronological calibration curve
International Nuclear Information System (INIS)
Ottaway, J.H.; Ottaway, B.
1975-01-01
A discussion is presented on the reality or otherwise of short-term deviations from a linear or smooth curve relating conventional C-14 dates to dendrochronological measurements. The possibility of the effect of short-term changes in the earth's atmosphere and in the oceans, and particularly in their temperature, is considered. (U.K.)
A spectral mean for random closed curves
van Lieshout, Maria Nicolette Margaretha
2016-01-01
We propose a spectral mean for closed sets described by sample points on their boundaries subject to mis-alignment and noise. We derive maximum likelihood estimators for the model and noise parameters in the Fourier domain. We estimate the unknown mean boundary curve by back-transformation and
A spectral mean for random closed curves
M.N.M. van Lieshout (Marie-Colette)
2016-01-01
textabstractWe propose a spectral mean for closed sets described by sample points on their boundaries subject to mis-alignment and noise. We derive maximum likelihood estimators for the model and noise parameters in the Fourier domain. We estimate the unknown mean boundary curve by
Contribution to the boiling curve of sodium
International Nuclear Information System (INIS)
Schins, H.E.J.
1975-01-01
Sodium in a pool was preheated to saturation temperatures at system pressures of 200, 350 and 500 torr. A test section of normal stainless steel was then extra heated by means of the conical fitting condenser zone of a heat pipe. Measurements were made of heat transfer fluxes, q in W/cm 2 , as a function of wall excess temperature above saturation, THETA = Tsub(w) - Tsub(s) in 0 C, both, in natural convection and in boiling regimes. These measurements make it possible to select the Subbotin natural convection and nucleate boiling curves among other variants proposed in literature. Further it is empirically demonstrated on water that the minimum film boiling point corresponds to the homogeneous nucleation temperature calculated by the Doering formula. Assuming that the minimum film boiling point of sodium can be obtained in the same manner, it is then possible to give an appoximate boiling curve of sodium for the use in thermal interaction studies. At 1 atm the heat transfer fluxes q versus wall temperatures THETA are for a point on the natural convection curve 0.3 W/cm 2 and 2 0 C; for start of boiling 1.6 W/cm 2 and 6 0 C; for peak heat flux 360 W/cm 2 and 37 0 C; for minimum film boiling 30 W/cm 2 and 905 0 C and for a point on the film boiling curve 160 W/cm 2 and 2,000 0 C. (orig.) [de
Designing the Alluvial Riverbeds in Curved Paths
Macura, Viliam; Škrinár, Andrej; Štefunková, Zuzana; Muchová, Zlatica; Majorošová, Martina
2017-10-01
The paper presents the method of determining the shape of the riverbed in curves of the watercourse, which is based on the method of Ikeda (1975) developed for a slightly curved path in sandy riverbed. Regulated rivers have essentially slightly and smoothly curved paths; therefore, this methodology provides the appropriate basis for river restoration. Based on the research in the experimental reach of the Holeška Brook and several alluvial mountain streams the methodology was adjusted. The method also takes into account other important characteristics of bottom material - the shape and orientation of the particles, settling velocity and drag coefficients. Thus, the method is mainly meant for the natural sand-gravel material, which is heterogeneous and the particle shape of the bottom material is very different from spherical. The calculation of the river channel in the curved path provides the basis for the design of optimal habitat, but also for the design of foundations of armouring of the bankside of the channel. The input data is adapted to the conditions of design practice.
Fermat's Technique of Finding Areas under Curves
Staples, Ed
2004-01-01
Perhaps next time teachers head towards the fundamental theorem of calculus in their classroom, they may wish to consider Fermat's technique of finding expressions for areas under curves, beautifully outlined in Boyer's History of Mathematics. Pierre de Fermat (1601-1665) developed some important results in the journey toward the discovery of the…
Variability of the Wind Turbine Power Curve
Directory of Open Access Journals (Sweden)
Mahesh M. Bandi
2016-09-01
Full Text Available Wind turbine power curves are calibrated by turbine manufacturers under requirements stipulated by the International Electrotechnical Commission to provide a functional mapping between the mean wind speed v ¯ and the mean turbine power output P ¯ . Wind plant operators employ these power curves to estimate or forecast wind power generation under given wind conditions. However, it is general knowledge that wide variability exists in these mean calibration values. We first analyse how the standard deviation in wind speed σ v affects the mean P ¯ and the standard deviation σ P of wind power. We find that the magnitude of wind power fluctuations scales as the square of the mean wind speed. Using data from three planetary locations, we find that the wind speed standard deviation σ v systematically varies with mean wind speed v ¯ , and in some instances, follows a scaling of the form σ v = C × v ¯ α ; C being a constant and α a fractional power. We show that, when applicable, this scaling form provides a minimal parameter description of the power curve in terms of v ¯ alone. Wind data from different locations establishes that (in instances when this scaling exists the exponent α varies with location, owing to the influence of local environmental conditions on wind speed variability. Since manufacturer-calibrated power curves cannot account for variability influenced by local conditions, this variability translates to forecast uncertainty in power generation. We close with a proposal for operators to perform post-installation recalibration of their turbine power curves to account for the influence of local environmental factors on wind speed variability in order to reduce the uncertainty of wind power forecasts. Understanding the relationship between wind’s speed and its variability is likely to lead to lower costs for the integration of wind power into the electric grid.
Curved bones: An adaptation to habitual loading.
Milne, Nick
2016-10-21
Why are long bones curved? It has long been considered a paradox that many long bones supporting mammalian bodies are curved, since this curvature results in the bone undergoing greater bending, with higher strains and so greater fracture risk under load. This study develops a theoretical model wherein the curvature is a response to bending strains imposed by the requirements of locomotion. In particular the radioulna of obligate quadrupeds is a lever operated by the triceps muscle, and the bending strains induced by the triceps muscle counter the bending resulting from longitudinal loads acting on the curved bone. Indeed the theoretical model reverses this logic and suggests that the curvature is itself a response to the predictable bending strains induced by the triceps muscle. This, in turn, results in anatomical arrangements of bone, muscle and tendon that create a simple physiological mechanism whereby the bone can resist the bending due to the action of triceps in supporting and moving the body. The model is illustrated by contrasting the behaviour of a finite element model of a llama radioulna to that of a straightened version of the same bone. The results show that longitudinal and flexor muscle forces produce bending strains that effectively counter strains due to the pull of the triceps muscle in the curved but not in the straightened model. It is concluded that the curvature of these and other curved bones adds resilience to the skeleton by acting as pre-stressed beams or strainable pre-buckled struts. It is also proposed that the cranial bending strains that result from triceps, acting on the lever that is the radioulna, can explain the development of the curvature of such bones. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.
New configuration factors for curved surfaces
International Nuclear Information System (INIS)
Cabeza-Lainez, Jose M.; Pulido-Arcas, Jesus A.
2013-01-01
Curved surfaces have not been thoroughly considered in radiative transfer analysis mainly due to the difficulties arisen in the integration process and perhaps because of the lack of spatial vision of the researchers. It is a fact, especially for architectural lighting, that when concave geometries appear inside a curved space, they are mostly avoided. In this way, a vast repertoire of significant forms is neglected and energy waste is evident. Starting from the properties of volumes enclosed by the minimum number of surfaces, the authors formulate, with little calculus, new simple laws, which enable them to discover a set of configuration factors for caps and various segments of the sphere. The procedure is subsequently extended to previously unimagined surfaces as the paraboloid, the ellipsoid or the cone. Appropriate combination of the said forms with right truncated cones produces several complex volumes, often used in architectural and engineering creations and whose radiative performance could not be accurately predicted for decades. To complete the research, a new method for determining interreflections in curved volumes is also presented. Radiative transfer simulation benefits from these findings, as the simplicity of the results has led the authors to create innovative software more efficient for design and evaluation and applicable to emerging fields like LED lighting. -- Highlights: ► Friendly revision of fundamentals of radiative transfer. ► New configuration factors for curved surfaces obtained without calculus. ► New method for interreflections in curved geometries. ► Enhanced simulation algorithms. ► Fast comparison of radiative performances of surfaces
IDF-curves for precipitation In Belgium
International Nuclear Information System (INIS)
Mohymont, Bernard; Demarde, Gaston R.
2004-01-01
The Intensity-Duration-Frequency (IDF) curves for precipitation constitute a relationship between the intensity, the duration and the frequency of rainfall amounts. The intensity of precipitation is expressed in mm/h, the duration or aggregation time is the length of the interval considered while the frequency stands for the probability of occurrence of the event. IDF-curves constitute a classical and useful tool that is primarily used to dimension hydraulic structures in general, as e.g., sewer systems and which are consequently used to assess the risk of inundation. In this presentation, the IDF relation for precipitation is studied for different locations in Belgium. These locations correspond to two long-term, high-quality precipitation networks of the RMIB: (a) the daily precipitation depths of the climatological network (more than 200 stations, 1951-2001 baseline period); (b) the high-frequency 10-minutes precipitation depths of the hydro meteorological network (more than 30 stations, 15 to 33 years baseline period). For the station of Uccle, an uninterrupted time-series of more than one hundred years of 10-minutes rainfall data is available. The proposed technique for assessing the curves is based on maximum annual values of precipitation. A new analytical formula for the IDF-curves was developed such that these curves stay valid for aggregation times ranging from 10 minutes to 30 days (when fitted with appropriate data). Moreover, all parameters of this formula have physical dimensions. Finally, adequate spatial interpolation techniques are used to provide nationwide extreme values precipitation depths for short- to long-term durations With a given return period. These values are estimated on the grid points of the Belgian ALADIN-domain used in the operational weather forecasts at the RMIB.(Author)
TELECOMMUNICATIONS INFRASTRUCTURE AND GDP /JIPP CURVE/
Directory of Open Access Journals (Sweden)
Mariana Kaneva
2016-07-01
Full Text Available The relationship between telecommunications infrastructure and economic activity is under discussion in many scientific papers. Most of the authors use for research and analysis the Jipp curve. A lot of doubts about the correctness of the Jipp curve appear in terms of applying econometric models. The aim of this study is a review of the Jipp curve, refining the possibility of its application in modern conditions. The methodology used in the study is based on dynamic econometric models, including tests for nonstationarity and tests for causality. The focus of this study is directed to methodological problems in measuring the local density types of telecommunication networks. This study offers a specific methodology for assessing the Jipp law, through VAR-approach and Granger causality tests. It is proved that mechanical substitution of momentary aggregated variables (such as the number of subscribers of a telecommunication network at the end of the year and periodically aggregated variables (such as GDP per capita in the Jipp�s curve is methodologically wrong. Researchers have to reconsider the relationship set in the Jipp�s curve by including additional variables that characterize the Telecommunications sector and the economic activity in a particular country within a specified time period. GDP per capita should not be regarded as a single factor for the local density of telecommunications infrastructure. New econometric models studying the relationship between the investments in telecommunications infrastructure and economic development may be not only linear regression models, but also other econometric models. New econometric models should be proposed after testing and validating with sound economic theory and econometric methodology.
Trend analyses with river sediment rating curves
Warrick, Jonathan A.
2015-01-01
Sediment rating curves, which are fitted relationships between river discharge (Q) and suspended-sediment concentration (C), are commonly used to assess patterns and trends in river water quality. In many of these studies it is assumed that rating curves have a power-law form (i.e., C = aQb, where a and b are fitted parameters). Two fundamental questions about the utility of these techniques are assessed in this paper: (i) How well to the parameters, a and b, characterize trends in the data? (ii) Are trends in rating curves diagnostic of changes to river water or sediment discharge? As noted in previous research, the offset parameter, a, is not an independent variable for most rivers, but rather strongly dependent on b and Q. Here it is shown that a is a poor metric for trends in the vertical offset of a rating curve, and a new parameter, â, as determined by the discharge-normalized power function [C = â (Q/QGM)b], where QGM is the geometric mean of the Q values sampled, provides a better characterization of trends. However, these techniques must be applied carefully, because curvature in the relationship between log(Q) and log(C), which exists for many rivers, can produce false trends in â and b. Also, it is shown that trends in â and b are not uniquely diagnostic of river water or sediment supply conditions. For example, an increase in â can be caused by an increase in sediment supply, a decrease in water supply, or a combination of these conditions. Large changes in water and sediment supplies can occur without any change in the parameters, â and b. Thus, trend analyses using sediment rating curves must include additional assessments of the time-dependent rates and trends of river water, sediment concentrations, and sediment discharge.
Makowska, Joanna; Bagiñska, Katarzyna; Makowski, Mariusz; Jagielska, Anna; Liwo, Adam; Kasprzykowski, Franciszek; Chmurzyñski, Lech; Scheraga, Harold A
2006-03-09
between the dissociation constants. Nevertheless, quantitative agreement between theoretically predicted and experimental titration curves is not achieved in all three solvents even with the MD-based approach, which is manifested by a smaller pH range of the calculated titration curves with respect to the experimental curves. The poorer agreement obtained for water than for the nonaqueous solvents suggests a significant role of specific solvation in water, which cannot be accounted for by the mean-field solvation models.
The shape of dose-effect curves for diploid yeast cells irradiated with ionizing particles
International Nuclear Information System (INIS)
Pohlit, W.
1975-01-01
In a cybernetic model for the radiation reactions in eukaryotic cells, after irradiation they are assumed to be in one of three states: (a) viable cells; (b) with repairable damage; and (c) with irreparable damage. Two biological counter reactions with certain time constants can be observed: (i) recovery from sublethal damage; and (ii) repair of potential lethal damage. The shape of the dose-effect curve is influenced in a characteristic way by the different occupation of these states of the cells and by the time constants of the biological counter reactions. The biochemical analysis of the biological counter reactions, recovery and repair, has shown that both are linked together by the energy pool in the cell. In this way changes in the slope of the dose-effect curve due to different metabolic states of the cells can be understood quantitatively. Also the complicated dependence of survival cells on the absorbed dose rate over a wide range can be explained quantitatively. (author)
Repair models of cell survival and corresponding computer program for survival curve fitting
International Nuclear Information System (INIS)
Shen Xun; Hu Yiwei
1992-01-01
Some basic concepts and formulations of two repair models of survival, the incomplete repair (IR) model and the lethal-potentially lethal (LPL) model, are introduced. An IBM-PC computer program for survival curve fitting with these models was developed and applied to fit the survivals of human melanoma cells HX118 irradiated at different dose rates. Comparison was made between the repair models and two non-repair models, the multitar get-single hit model and the linear-quadratic model, in the fitting and analysis of the survival-dose curves. It was shown that either IR model or LPL model can fit a set of survival curves of different dose rates with same parameters and provide information on the repair capacity of cells. These two mathematical models could be very useful in quantitative study on the radiosensitivity and repair capacity of cells
A Composite Light Curve Model of the Symbiotic Nova PU Vul (1979
Directory of Open Access Journals (Sweden)
Kato M.
2012-06-01
Full Text Available PU Vul (1979 is a symbiotic nova that shows a long-lasting flat optical peak followed by a slow decline. We made a quasi-evolution model for outbursts on a 0.6 M⊙ white dwarf consisting of a series of static solutions with optically-thin winds. Our theoretical models reproduce well the observed visual/UV light curves as well as the new estimates of the temperature and radius of the hot component. We also modeled the light curve of the 1980 and 1994 eclipses as the total eclipse occulted by a pulsating M-giant companion star. In the second eclipse, the visual magnitude is dominated by nebular emission which is possibly ejected from the hot component between 1990 to 2000. We have quantitatively estimated three components of emission, i.e., the white dwarf, companion and nebular, and made a composite light curve that represents well the evolution of the PU Vul outburst.
Nonparametric estimation of age-specific reference percentile curves with radial smoothing.
Wan, Xiaohai; Qu, Yongming; Huang, Yao; Zhang, Xiao; Song, Hanping; Jiang, Honghua
2012-01-01
Reference percentile curves represent the covariate-dependent distribution of a quantitative measurement and are often used to summarize and monitor dynamic processes such as human growth. We propose a new nonparametric method based on a radial smoothing (RS) technique to estimate age-specific reference percentile curves assuming the underlying distribution is relatively close to normal. We compared the RS method with both the LMS and the generalized additive models for location, scale and shape (GAMLSS) methods using simulated data and found that our method has smaller estimation error than the two existing methods. We also applied the new method to analyze height growth data from children being followed in a clinical observational study of growth hormone treatment, and compared the growth curves between those with growth disorders and the general population. Copyright © 2011 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Devine, G.; Dobie, D.; Fugina, J.; Hernandez, J.; Logan, C.; Mohr, P.; Moss, R.; Schumacher, B.; Updike, E.; Weirup, D.
1991-01-01
We have developed a system of quantitative radiography in order to produce quantitative images displaying homogeneity of parts. The materials that we characterize are synthetic composites and may contain important subtle density variations not discernible by examining a raw film x-radiograph. In order to quantitatively interpret film radiographs, it is necessary to digitize, interpret, and display the images. Our integrated system of quantitative radiography displays accurate, high-resolution pseudo-color images in units of density. We characterize approximately 10,000 parts per year in hundreds of different configurations and compositions with this system. This report discusses: the method; film processor monitoring and control; verifying film and processor performance; and correction of scatter effects
Part 5: Receiver Operating Characteristic Curve and Area under the Curve
Directory of Open Access Journals (Sweden)
Saeed Safari
2016-04-01
Full Text Available Multiple diagnostic tools are used by emergency physicians,every day. In addition, new tools are evaluated to obtainmore accurate methods and reduce time or cost of conventionalones. In the previous parts of this educationalseries, we described diagnostic performance characteristicsof diagnostic tests including sensitivity, specificity, positiveand negative predictive values, and likelihood ratios. Thereceiver operating characteristics (ROC curve is a graphicalpresentation of screening characteristics. ROC curve is usedto determine the best cutoff point and compare two or moretests or observers by measuring the area under the curve(AUC. In this part of our educational series, we explain ROCcurve and two methods to determine the best cutoff value.
A mathematical function for the description of nutrient-response curve.
Directory of Open Access Journals (Sweden)
Hamed Ahmadi
Full Text Available Several mathematical equations have been proposed to modeling nutrient-response curve for animal and human justified on the goodness of fit and/or on the biological mechanism. In this paper, a functional form of a generalized quantitative model based on Rayleigh distribution principle for description of nutrient-response phenomena is derived. The three parameters governing the curve a has biological interpretation, b may be used to calculate reliable estimates of nutrient response relationships, and c provide the basis for deriving relationships between nutrient and physiological responses. The new function was successfully applied to fit the nutritional data obtained from 6 experiments including a wide range of nutrients and responses. An evaluation and comparison were also done based simulated data sets to check the suitability of new model and four-parameter logistic model for describing nutrient responses. This study indicates the usefulness and wide applicability of the new introduced, simple and flexible model when applied as a quantitative approach to characterizing nutrient-response curve. This new mathematical way to describe nutritional-response data, with some useful biological interpretations, has potential to be used as an alternative approach in modeling nutritional responses curve to estimate nutrient efficiency and requirements.
Advanced distillation curve measurements for corrosive fluids: Application to two crude oils
Energy Technology Data Exchange (ETDEWEB)
Lisa Starkey Ott; Beverly L. Smith; Thomas J. Bruno [National Institute of Standards and Technology, Boulder, CO (United States). Physical and Chemical Properties Division
2008-10-15
We have recently introduced several important improvements in the measurement of distillation curves for complex fluids. The modifications include a composition-explicit data channel for each distillate fraction (for both qualitative and quantitative analysis) and corrosivity assessment of each distillate fraction. The composition-explicit information is achieved with a new sampling approach that allows precise qualitative as well as quantitative analyses of each fraction, on the fly. We have applied the new method to a variety of fluids, including simple n-alkanes, rocket propellant, gasoline, jet fuels, and a hydrocarbon fluid made corrosive with dissolved hydrogen sulfide. In the current contribution, we present the application of the advanced distillation curve method to two samples of crude oil. A primary motivation behind the work is to precisely measure the distillation curves of these oils using our advanced distillation apparatus; these low uncertainty measurements of true thermodynamic state points can be used for equation of state development and differentiation of crude oil samples. Then, the information content of each distillation was extended much further by use of the composition-explicit data channel: gas chromatography-mass spectrometry (GC-MS), infrared spectrophotometry (IR), gas chromatography with sulfur chemiluminescence detection (GC-SCD), and the copper strip corrosion test (CSCT) were used for each distillate volume fraction sampled. Consequently, for each volume fraction of crude oil distillate sampled, we can address the composition, quantitate the total sulfur content, and measure the corrosivity. 39 refs., 6 figs., 2 tabs.
On harmonic curvatures of a Frenet curve in Lorentzian space
International Nuclear Information System (INIS)
Kuelahci, Mihriban; Bektas, Mehmet; Erguet, Mahmut
2009-01-01
In this paper, we consider curves of AW(k)-type, 1 ≤ k ≤ 3, in Lorentzian space. We give curvature conditions of these kind of curves. Furthermore, we study harmonic curvatures of curves of AW(k)-type. We investigate that under what conditions AW(k)-type curves are helix. Some related theorems and corollaries are also proved.
49 CFR 213.59 - Elevation of curved track; runoff.
2010-10-01
... 49 Transportation 4 2010-10-01 2010-10-01 false Elevation of curved track; runoff. 213.59 Section... track; runoff. (a) If a curve is elevated, the full elevation shall be provided throughout the curve, unless physical conditions do not permit. If elevation runoff occurs in a curve, the actual minimum...
The spatial profile of visual attention in mental curve tracing
Scholte, H. S.; Spekreijse, H.; Roelfsema, P. R.
2001-01-01
In a curve-tracing task, subjects have to judge whether items are located on a single, continuous curve. Spatially separate segments of such a curve are related to each other through grouping criteria, like collinearity and connectedness. These grouping cues need to be exploited during curve
R-curve behaviour of ferroelectric ceramics
International Nuclear Information System (INIS)
Egorov, N.Ya.; Kramarov, S.O.
2004-01-01
The attempt's made to identify and evaluate the regularities of developing the fractures in the ferroelectric ceramics and also-study the effect of the polishing operation on the strength characteristics of the piezoceramics. The R-curve behaviour in the ferroelectric ceramics is studied on the samples of the barium titanate and lead zirconate-titanate by the four-point bending with controlled surface fractures. It is established that increasing curve of resistance to the fracture growth is observed in the piezoceramics under the conditions of the fracture stable growth. The results obtained on the polished samples prove that the mechanical processing introduces the compression surface stresses into the piezoceramic materials [ru
Graphical evaluation of complexometric titration curves.
Guinon, J L
1985-04-01
A graphical method, based on logarithmic concentration diagrams, for construction, without any calculations, of complexometric titration curves is examined. The titration curves obtained for different kinds of unidentate, bidentate and quadridentate ligands clearly show why only chelating ligands are usually used in titrimetric analysis. The method has also been applied to two practical cases where unidentate ligands are used: (a) the complexometric determination of mercury(II) with halides and (b) the determination of cyanide with silver, which involves both a complexation and a precipitation system; for this purpose construction of the diagrams for the HgCl(2)/HgCl(+)/Hg(2+) and Ag(CN)(2)(-)/AgCN/CN(-) systems is considered in detail.
On quadratic residue codes and hyperelliptic curves
Directory of Open Access Journals (Sweden)
David Joyner
2008-01-01
Full Text Available For an odd prime p and each non-empty subset S⊂GF(p, consider the hyperelliptic curve X S defined by y 2 =f S (x, where f S (x = ∏ a∈S (x-a. Using a connection between binary quadratic residue codes and hyperelliptic curves over GF(p, this paper investigates how coding theory bounds give rise to bounds such as the following example: for all sufficiently large primes p there exists a subset S⊂GF(p for which the bound |X S (GF(p| > 1.39p holds. We also use the quasi-quadratic residue codes defined below to construct an example of a formally self-dual optimal code whose zeta function does not satisfy the ``Riemann hypothesis.''
Geometry of curves and surfaces with Maple
Rovenski, Vladimir
2000-01-01
This concise text on geometry with computer modeling presents some elementary methods for analytical modeling and visualization of curves and surfaces. The author systematically examines such powerful tools as 2-D and 3-D animation of geometric images, transformations, shadows, and colors, and then further studies more complex problems in differential geometry. Well-illustrated with more than 350 figures---reproducible using Maple programs in the book---the work is devoted to three main areas: curves, surfaces, and polyhedra. Pedagogical benefits can be found in the large number of Maple programs, some of which are analogous to C++ programs, including those for splines and fractals. To avoid tedious typing, readers will be able to download many of the programs from the Birkhauser web site. Aimed at a broad audience of students, instructors of mathematics, computer scientists, and engineers who have knowledge of analytical geometry, i.e., method of coordinates, this text will be an excellent classroom resource...
Estimation of curve number by DAWAST model
Energy Technology Data Exchange (ETDEWEB)
Kim, Tai Cheol; Park, Seung Ki; Moon, Jong Pil [Chungnam National University, Taejon (Korea, Republic of)
1997-10-31
It is one of the most important factors to determine the effective rainfall for estimation of flood hydrograph in design schedule. SCS curve number (CN) method has been frequently used to estimate the effective rainfall of synthesized design flood hydrograph for hydraulic structures. But, it should be cautious to apply SCS-CN originally developed in U.S.A to watersheds in Korea, because characteristics of watersheds in Korea and cropping patterns especially like a paddy land cultivation are quite different from those in USA. New CN method has been introduced. Maximum storage capacity which was herein defined as U{sub max} can be calibrated from the stream flow data and converted to new CN-I of driest condition of soil moisture in the given watershed. Effective rainfall for design flood hydrograph can be estimated by the curve number developed in the watersheds in Korea. (author). 14 refs., 5 tabs., 3 figs.
An approach to averaging digitized plantagram curves.
Hawes, M R; Heinemeyer, R; Sovak, D; Tory, B
1994-07-01
The averaging of outline shapes of the human foot for the purposes of determining information concerning foot shape and dimension within the context of comfort of fit of sport shoes is approached as a mathematical problem. An outline of the human footprint is obtained by standard procedures and the curvature is traced with a Hewlett Packard Digitizer. The paper describes the determination of an alignment axis, the identification of two ray centres and the division of the total curve into two overlapping arcs. Each arc is divided by equiangular rays which intersect chords between digitized points describing the arc. The radial distance of each ray is averaged within groups of foot lengths which vary by +/- 2.25 mm (approximately equal to 1/2 shoe size). The method has been used to determine average plantar curves in a study of 1197 North American males (Hawes and Sovak 1993).
Daylight calculations using constant luminance curves
Energy Technology Data Exchange (ETDEWEB)
Betman, E. [CRICYT, Mendoza (Argentina). Laboratorio de Ambiente Humano y Vivienda
2005-02-01
This paper presents a simple method to manually estimate daylight availability and to make daylight calculations using constant luminance curves calculated with local illuminance and irradiance data and the all-weather model for sky luminance distribution developed in the Atmospheric Science Research Center of the University of New York (ARSC) by Richard Perez et al. Work with constant luminance curves has the advantage that daylight calculations include the problem's directionality and preserve the information of the luminous climate of the place. This permits accurate knowledge of the resource and a strong basis to establish conclusions concerning topics related to the energy efficiency and comfort in buildings. The characteristics of the proposed method are compared with the method that uses the daylight factor. (author)
Gauge field configurations in curved spacetimes (II)
International Nuclear Information System (INIS)
Boutaleb-Joutei, H.; Chakrabarti, A.; Comtet, A.
1979-05-01
One continues the study of gauge field configurations in curved spaces, using the formalism and results of a previous paper. A class of static, finite action, selfdual solutions of SU(2) gauge fields on a Euclidean section of de Sitter space is presented. The action depends on a continuous parameter. The spin connection solution is obtained as a particular case and a certain passage to the limiting case of a flat space is shown to reproduce the Euclidean Prasad-Sommerfield solution. The significance and possible interest of such solutions are discussed. The results are then generalized to a non-Einstein but conformally flat space, including de Sitter space as an Einstein limit. Next Baecklund type transformations are constructed starting from selfduality constraints for such curved spaces. These transformations are applied to the above mentioned solutions. The last two sections contain remarks on solutions with a background Robinson-Bertotti metric and on static, axially symmetric solutions respectively
Point- and curve-based geometric conflation
Ló pez-Vá zquez, C.; Manso Callejo, M.A.
2013-01-01
Geometric conflation is the process undertaken to modify the coordinates of features in dataset A in order to match corresponding ones in dataset B. The overwhelming majority of the literature considers the use of points as features to define the transformation. In this article we present a procedure to consider one-dimensional curves also, which are commonly available as Global Navigation Satellite System (GNSS) tracks, routes, coastlines, and so on, in order to define the estimate of the displacements to be applied to each object in A. The procedure involves three steps, including the partial matching of corresponding curves, the computation of some analytical expression, and the addition of a correction term in order to satisfy basic cartographic rules. A numerical example is presented. © 2013 Copyright Taylor and Francis Group, LLC.
Pathophysiological Characteristics Underlying Different Glucose Response Curves
DEFF Research Database (Denmark)
Hulman, Adam; Witte, Daniel R; Vistisen, Dorte
2018-01-01
different glucose curve patterns and studied their stability and reproducibility over 3 years of follow-up. RESEARCH DESIGN AND METHODS: We analyzed data from participants without diabetes from the observational cohort from the European Group for the Study of Insulin Resistance: Relationship between Insulin...... and secretion. The glucose patterns identified at follow-up were similar to those at baseline, suggesting that the latent class method is robust. We integrated our classification model into an easy-to-use online application that facilitates the assessment of glucose curve patterns for other studies. CONCLUSIONS...... Sensitivity and Cardiovascular Disease study; participants had a five-time point OGTT at baseline (n = 1,443) and after 3 years (n = 1,045). Measures of insulin sensitivity and secretion were assessed at baseline with a euglycemic-hyperinsulinemic clamp and intravenous glucose tolerance test. Heterogeneous...
Yield stress independent column buckling curves
DEFF Research Database (Denmark)
Stan, Tudor‐Cristian; Jönsson, Jeppe
2017-01-01
of the yield stress is to some inadequate degree taken into account in the Eurocode by specifying that steel grades of S460 and higher all belong to a common set of “raised” buckling curves. This is not satisfying as it can be shown theoretically that the current Eurocode formulation misses an epsilon factor......Using GMNIA and shell finite element modelling of steel columns it is ascertained that the buckling curves for given imperfections and residual stresses are not only dependent on the relative slenderness ratio and the cross section shape but also on the magnitude of the yield stress. The influence...... in the definition of the normalised imperfection magnitudes. By introducing this factor it seems that the GMNIA analysis and knowledge of the independency of residual stress levels on the yield stress can be brought together and give results showing consistency between numerical modelling and a simple modified...
Curved butterfly bileaflet prosthetic cardiac valve
McQueen, David M.; Peskin, Charles S.
1991-06-25
An annular valve body having a central passageway for the flow of blood therethrough with two curved leaflets each of which is pivotally supported on an accentric positioned axis in the central passageway for moving between a closed position and an open position. The leaflets are curved in a plane normal to the eccentric axis and positioned with the convex side of the leaflets facing each other when the leaflets are in the open position. Various parameters such as the curvature of the leaflets, the location of the eccentric axis, and the maximum opening angle of the leaflets are optimized according to the following performance criteria: maximize the minimum peak velocity through the valve, maximize the net stroke volume, and minimize the mean forward pressure difference, thereby reducing thrombosis and improving the hemodynamic performance.
The Green functions in curved spacetime
International Nuclear Information System (INIS)
Buchbinder, I.L.; Kirillova, E.N.; Odinstov, S.D.
1987-01-01
The theory of a free scalar field with conformal coupling in curved spacetime with some special metrics is considered. The integral representations for the green function G-tilde in the form of integrals with Schwinger-De Witt kernel over contours in the complex plane of proper time are obtained. It is shown how the transitions from a unique Green function in Euclidean space to different Green functions in Minkowski space and vice versa can be carried out. (author)
Advection endash diffusion around a curved obstacle
International Nuclear Information System (INIS)
Ahluwalia, D.S.; Keller, J.B.; Knessl, C.
1998-01-01
Advection and diffusion of a substance around a curved obstacle is analyzed when the advection velocity is large compared to the diffusion velocity, i.e., when the Peclet number is large. Asymptotic expressions for the concentration are obtained by the use of boundary layer theory, matched asymptotic expansions, etc. The results supplement and extend previous ones for straight obstacles. They apply to electrophoresis, the flow of ground water, chromatography, sedimentation, etc. copyright 1998 American Institute of Physics
The Astral Curved Disc of Chevroches (France)
Devevey, F. Rousseau, A.
2009-08-01
The excavation of the unexplored secondary agglomeration in Chevroches (Nièvre), from 2001 to 2002, directed by F. Devevey (INRAP), has led to the discovery of an astrological bronze curved disc of a type unknown in the ancient world; it is inscribed with three lines in Greek transcribing Egyptian an Roman months, and the twelve signs of the zodiac. This article presents the first observations.
Structural properties of the Hugoniot curve
International Nuclear Information System (INIS)
Chaisse, F.
2002-01-01
This report is devoted to the structural properties analysis of the HUGONIOT curve, independently of the equation of state (E 0 S) display. The general properties so coming out are applied to the shock waves interacting studies. When phase transitions are present we investigate the splitting of shock waves and also the rarefaction waves. To end with, we present the shock instabilities and the non-uniqueness of solutions when specific E 0 S are present. (author)
SPOTTED STAR LIGHT CURVES WITH ENHANCED PRECISION
International Nuclear Information System (INIS)
Wilson, R. E.
2012-01-01
The nearly continuous timewise coverage of recent photometric surveys is free of the large gaps that compromise attempts to follow starspot growth and decay as well as motions, thereby giving incentive to improve computational precision for modeled spots. Due to the wide variety of star systems in the surveys, such improvement should apply to light/velocity curve models that accurately include all the main phenomena of close binaries and rotating single stars. The vector fractional area (VFA) algorithm that is introduced here represents surface elements by small sets of position vectors so as to allow accurate computation of circle-triangle overlap by spherical geometry. When computed by VFA, spots introduce essentially no noticeable scatter in light curves at the level of one part in 10,000. VFA has been put into the Wilson-Devinney light/velocity curve program and all logic and mathematics are given so as to facilitate entry into other such programs. Advantages of precise spot computation include improved statistics of spot motions and aging, reduced computation time (intrinsic precision relaxes needs for grid fineness), noise-free illustration of spot effects in figures, and help in guarding against false positives in exoplanet searches, where spots could approximately mimic transiting planets in unusual circumstances. A simple spot growth and decay template quantifies time profiles, and specifics of its utilization in differential corrections solutions are given. Computational strategies are discussed, the overall process is tested in simulations via solutions of synthetic light curve data, and essential simulation results are described. An efficient time smearing facility by Gaussian quadrature can deal with Kepler mission data that are in 30 minute time bins.
Quantum field theory in curved spacetime
International Nuclear Information System (INIS)
Gibbons, G.W.
1978-04-01
The purpose of this article is to outline what the extension of such a treatment to curved space entails and to discuss what essentially new features arise when one takes into account the quantum mechanical nature of gravitating systems. I shall throughout assume a classical, unquantized gravitational field and confine the discussion to matter fields although similar techniques and ideas may be applied to 'gravitons' - that is linearized perturbations of the metric propagating on some fixed, unperturbed, background. (orig./WL) [de
Robotic Mitral Valve Repair: The Learning Curve.
Goodman, Avi; Koprivanac, Marijan; Kelava, Marta; Mick, Stephanie L; Gillinov, A Marc; Rajeswaran, Jeevanantham; Brzezinski, Anna; Blackstone, Eugene H; Mihaljevic, Tomislav
Adoption of robotic mitral valve surgery has been slow, likely in part because of its perceived technical complexity and a poorly understood learning curve. We sought to correlate changes in technical performance and outcome with surgeon experience in the "learning curve" part of our series. From 2006 to 2011, two surgeons undertook robotically assisted mitral valve repair in 458 patients (intent-to-treat); 404 procedures were completed entirely robotically (as-treated). Learning curves were constructed by modeling surgical sequence number semiparametrically with flexible penalized spline smoothing best-fit curves. Operative efficiency, reflecting technical performance, improved for (1) operating room time for case 1 to cases 200 (early experience) and 400 (later experience), from 414 to 364 to 321 minutes (12% and 22% decrease, respectively), (2) cardiopulmonary bypass time, from 148 to 102 to 91 minutes (31% and 39% decrease), and (3) myocardial ischemic time, from 119 to 75 to 68 minutes (37% and 43% decrease). Composite postoperative complications, reflecting safety, decreased from 17% to 6% to 2% (63% and 85% decrease). Intensive care unit stay decreased from 32 to 28 to 24 hours (13% and 25% decrease). Postoperative stay fell from 5.2 to 4.5 to 3.8 days (13% and 27% decrease). There were no in-hospital deaths. Predischarge mitral regurgitation of less than 2+, reflecting effectiveness, was achieved in 395 (97.8%), without correlation to experience; return-to-work times did not change substantially with experience. Technical efficiency of robotic mitral valve repair improves with experience and permits its safe and effective conduct.
Hydrogen technologies and the technology learning curve
International Nuclear Information System (INIS)
Rogner, H.-H.
1998-01-01
On their bumpy road to commercialization, hydrogen production, delivery and conversion technologies not only require dedicated research, development and demonstration efforts, but also protected niche markets and early adopters. While niche markets utilize the unique technological properties of hydrogen, adopters exhibit a willingness to pay a premium for hydrogen fueled energy services. The concept of the technology learning curve is applied to estimate the capital requirements associated with the commercialization process of several hydrogen technologies. (author)
Growth curve models and statistical diagnostics
Pan, Jian-Xin
2002-01-01
Growth-curve models are generalized multivariate analysis-of-variance models. These models are especially useful for investigating growth problems on short times in economics, biology, medical research, and epidemiology. This book systematically introduces the theory of the GCM with particular emphasis on their multivariate statistical diagnostics, which are based mainly on recent developments made by the authors and their collaborators. The authors provide complete proofs of theorems as well as practical data sets and MATLAB code.
News Impact Curve for Stochastic Volatility Models
Makoto Takahashi; Yasuhiro Omori; Toshiaki Watanabe
2012-01-01
This paper proposes a new method to compute the news impact curve for stochastic volatility (SV) models. The new method incorporates the joint movement of return and volatility, which has been ignored by the extant literature, by simply adding a couple of steps to the Bayesian MCMC estimation procedures for SV models. This simple procedure is versatile and applicable to various SV type models. Contrary to the monotonic news impact functions in the extant literature, the new method gives a U-s...
Bezier Curve Modeling for Neutrosophic Data Problem
Directory of Open Access Journals (Sweden)
Ferhat Tas
2017-02-01
Full Text Available Neutrosophic set concept is defined with membership, non-membership and indeterminacy degrees. This concept is the solution and representation of the problems with various fields. In this paper, a geometric model is introduced for Neutrosophic data problem for the first time. This model is based on neutrosophic sets and neutrosophic relations. Neutrosophic control points are defined according to these points, resulting in neutrosophic Bezier curves.
Feynman propagator in curved space-time
International Nuclear Information System (INIS)
Candelas, P.; Raine, D.J.
1977-01-01
The Wick rotation is generalized in a covariant manner so as to apply to curved manifolds in a way that is independent of the analytic properties of the manifold. This enables us to show that various methods for defining a Feynman propagator to be found in the literature are equivalent where they are applicable. We are also able to discuss the relation between certain regularization methods that have been employed
Mannheim Curves in Nonflat 3-Dimensional Space Forms
Directory of Open Access Journals (Sweden)
Wenjing Zhao
2015-01-01
Full Text Available We consider the Mannheim curves in nonflat 3-dimensional space forms (Riemannian or Lorentzian and we give the concept of Mannheim curves. In addition, we investigate the properties of nonnull Mannheim curves and their partner curves. We come to the conclusion that a necessary and sufficient condition is that a linear relationship with constant coefficients will exist between the curvature and the torsion of the given original curves. In the case of null curve, we reveal that there are no null Mannheim curves in the 3-dimensional de Sitter space.
Development of a statistically-based lower bound fracture toughness curve (Ksub(IR) curve)
International Nuclear Information System (INIS)
Wullaert, R.A.; Server, W.L.; Oldfield, W.; Stahlkopf, K.E.
1977-01-01
A program of initiation fracture toughness measurements on fifty heats of nuclear pressure vessel production materials (including weldments) was used to develop a methodology for establishing a revised reference toughness curve. The new methodology was statistically developed and provides a predefined confidence limit (or tolerance limit) for fracture toughness based upon many heats of a particular type of material. Overall reference curves were developed for seven specific materials using large specimen static and dynamic fracture toughness results. The heat-to-heat variation was removed by normalizing both the fracture toughness and temperature data with the precracked Charpy tanh curve coefficients for each particular heat. The variance and distribution about the curve were determined, and lower bounds of predetermined statistical significance were drawn based upon a Pearson distribution in the lower shelf region (since the data were skewed to high values) and a t-distribution in the transition temperature region (since the data were normally distributed)
A learning curve for solar thermal power
Platzer, Werner J.; Dinter, Frank
2016-05-01
Photovoltaics started its success story by predicting the cost degression depending on cumulated installed capacity. This so-called learning curve was published and used for predictions for PV modules first, then predictions of system cost decrease also were developed. This approach is less sensitive to political decisions and changing market situations than predictions on the time axis. Cost degression due to innovation, use of scaling effects, improved project management, standardised procedures including the search for better sites and optimization of project size are learning effects which can only be utilised when projects are developed. Therefore a presentation of CAPEX versus cumulated installed capacity is proposed in order to show the possible future advancement of the technology to politics and market. However from a wide range of publications on cost for CSP it is difficult to derive a learning curve. A logical cost structure for direct and indirect capital expenditure is needed as the basis for further analysis. Using derived reference cost for typical power plant configurations predictions of future cost have been derived. Only on the basis of that cost structure and the learning curve levelised cost of electricity for solar thermal power plants should be calculated for individual projects with different capacity factors in various locations.
J-holomorphic curves and quantum cohomology
McDuff, Dusa
1994-01-01
J-holomorphic curves revolutionized the study of symplectic geometry when Gromov first introduced them in 1985. Through quantum cohomology, these curves are now linked to many of the most exciting new ideas in mathematical physics. This book presents the first coherent and full account of the theory of J-holomorphic curves, the details of which are presently scattered in various research papers. The first half of the book is an expository account of the field, explaining the main technical aspects. McDuff and Salamon give complete proofs of Gromov's compactness theorem for spheres and of the existence of the Gromov-Witten invariants. The second half of the book focuses on the definition of quantum cohomology. The authors establish that this multiplication exists, and give a new proof of the Ruan-Tian result that is associative on appropriate manifolds. They then describe the Givental-Kim calculation of the quantum cohomology of flag manifolds, leading to quantum Chern classes and Witten's calculation for Gras...
The free Maxwell field in curved spacetime
International Nuclear Information System (INIS)
Kueskue, M.
2001-09-01
The aim of this thesis is to discuss quantizations of the free Maxwell field in flat and curved spacetimes. First we introduce briefly some notions from tensor analysis and the causal structure of spacetime. As an introduction to the main topic, we review some aspects of the two axiomatic quantum field theories, Wightman theory and algebraic quantum field theory. We also give an introduction into concepts of the quantization of fields on curved spacetime backgrounds. Then the wave equation and quantization of the Maxwell field in flat spacetimes is discussed. It follows a review of J. Dimock's quantization of the Maxwell field on curved spacetimes and then we come to our main result: We show explicitly that the Maxwell field, defined by dF=0 and δF=0, has a well posed initial value formulation on arbitrary globally hyperbolic spacetime manifolds. We prove the existence and uniqueness of fundamental solutions without employing a vector potential. Thus our solution is also applicable to spacetimes not satisfying the Poincare lemma and should lead to a quantization of the Maxwell field on non-trivial spacetime backgrounds. This in turn provides the opportunity to investigate physical states on non-trivial spacetime-topologies and could lead to the discovery of new quantum phenomena. (orig.)
Shape optimization of self-avoiding curves
Walker, Shawn W.
2016-04-01
This paper presents a softened notion of proximity (or self-avoidance) for curves. We then derive a sensitivity result, based on shape differential calculus, for the proximity. This is combined with a gradient-based optimization approach to compute three-dimensional, parameterized curves that minimize the sum of an elastic (bending) energy and a proximity energy that maintains self-avoidance by a penalization technique. Minimizers are computed by a sequential-quadratic-programming (SQP) method where the bending energy and proximity energy are approximated by a finite element method. We then apply this method to two problems. First, we simulate adsorbed polymer strands that are constrained to be bound to a surface and be (locally) inextensible. This is a basic model of semi-flexible polymers adsorbed onto a surface (a current topic in material science). Several examples of minimizing curve shapes on a variety of surfaces are shown. An advantage of the method is that it can be much faster than using molecular dynamics for simulating polymer strands on surfaces. Second, we apply our proximity penalization to the computation of ideal knots. We present a heuristic scheme, utilizing the SQP method above, for minimizing rope-length and apply it in the case of the trefoil knot. Applications of this method could be for generating good initial guesses to a more accurate (but expensive) knot-tightening algorithm.
Numerical Characterization of Piezoceramics Using Resonance Curves
Pérez, Nicolás; Buiochi, Flávio; Brizzotti Andrade, Marco Aurélio; Adamowski, Julio Cezar
2016-01-01
Piezoelectric materials characterization is a challenging problem involving physical concepts, electrical and mechanical measurements and numerical optimization techniques. Piezoelectric ceramics such as Lead Zirconate Titanate (PZT) belong to the 6 mm symmetry class, which requires five elastic, three piezoelectric and two dielectric constants to fully represent the material properties. If losses are considered, the material properties can be represented by complex numbers. In this case, 20 independent material constants are required to obtain the full model. Several numerical methods have been used to adjust the theoretical models to the experimental results. The continuous improvement of the computer processing ability has allowed the use of a specific numerical method, the Finite Element Method (FEM), to iteratively solve the problem of finding the piezoelectric constants. This review presents the recent advances in the numerical characterization of 6 mm piezoelectric materials from experimental electrical impedance curves. The basic strategy consists in measuring the electrical impedance curve of a piezoelectric disk, and then combining the Finite Element Method with an iterative algorithm to find a set of material properties that minimizes the difference between the numerical impedance curve and the experimental one. Different methods to validate the results are also discussed. Examples of characterization of some common piezoelectric ceramics are presented to show the practical application of the described methods. PMID:28787875
Detection of flaws below curved surfaces
International Nuclear Information System (INIS)
Elsley, R.K.; Addison, R.C.; Graham, L.J.
1983-01-01
A measurement model has been developed to describe ultrasonic measurements made with circular piston transducers in parts with flat or cylindrically curved surfaces. The model includes noise terms to describe electrical noise, scatterer noise and echo noise as well as effects of attenuation, diffraction and Fresnel loss. An experimental procedure for calibrating the noise terms of the model was developed. Experimental measurements were made on a set of known flaws located beneath a cylindrically curved surface. The model was verified by using it to correct the experimental measurements to obtain the absolute scattering amplitude of the flaws. For longitudinal wave propagation within the part, the derived scattering amplitudes were consistent with predictions at internal angles of less than 30 0 . At larger angles, focusing and aberrations caused a lack of agreement; the model needs further refinement in this case. For shear waves, it was found that the frequency for optimum flaw detection in the presence of material noise is lower than that for longitudinal waves; lower frequency measurements are currently in progress. The measurement model was then used to make preliminary predictions of the best experimental measurement technique for the detection of cracks located under cylindrically curved surfaces
Prospects for PV: a learning curve analysis
International Nuclear Information System (INIS)
Zwaan, Bob van der; Rabi, A.
2003-01-01
This article gives an overview of the current state-of-the-art of photovoltaic electricity technology, and addresses its potential for cost reductions over the first few decades of the 21st century. Current PV production cost ranges are presented, both in terms of capacity installation and electricity generation, of single crystalline silicon, multi-crystalline silicon, amorphous silicon and other thin film technologies. Possible decreases of these costs are assessed, as expected according to the learning-curve methodology. We also estimate how much PV could gain if external costs (due to environmental and health damage) of energy were internalised, for example by an energy tax. Our conclusions are that, (1) mainly due its high costs, PV electricity is unlikely to play a major role in global energy supply and carbon emissions abatement before 2020, (2) extrapolating learning curves observed in the past, one can expect its costs to decrease significantly over the coming years, so that a considerable PV electricity share world-wide could materialise after 2020, (3) niche-market applications, e.g. using stand-alone systems in remote areas, are crucial for continuing 'the ride along the learning curve', (4) damage costs of conventional (fossil) power sources are considerable, and their internalisation would improve the competitiveness of PV, although probably not enough to close the current cost gap. (author)
Serial position curves in free recall.
Laming, Donald
2010-01-01
The scenario for free recall set out in Laming (2009) is developed to provide models for the serial position curves from 5 selected sets of data, for final free recall, and for multitrial free recall. The 5 sets of data reflect the effects of rate of presentation, length of list, delay of recall, and suppression of rehearsal. Each model accommodates the serial position curve for first recalls (where those data are available) as well as that for total recalls. Both curves are fit with the same parameter values, as also (with 1 exception) are all of the conditions compared within each experiment. The distributions of numbers of recalls are also examined and shown to have variances increased above what would be expected if successive recalls were independent. This is taken to signify that, in those experiments in which rehearsals were not recorded, the retrieval of words for possible recall follows the same pattern that is observed following overt rehearsal, namely, that retrieval consists of runs of consecutive elements from memory. Finally, 2 sets of data are examined that the present approach cannot accommodate. It is argued that the problem with these data derives from an interaction between the patterns of (covert) rehearsal and the parameters of list presentation.
Learning curve for radical retropubic prostatectomy
Directory of Open Access Journals (Sweden)
Fernando J. A. Saito
2011-02-01
Full Text Available PURPOSE: The learning curve is a period in which the surgical procedure is performed with difficulty and slowness, leading to a higher risk of complications and reduced effectiveness due the surgeon's inexperience. We sought to analyze the residents' learning curve for open radical prostatectomy (RP in a training program. MATERIALS AND METHODS: We conducted a prospective study from June 2006 to January 2008 in the academic environment of the University of São Paulo. Five residents operated on 184 patients during a four-month rotation in the urologic oncology division, mentored by the same physician assistants. We performed sequential analyses according to the number of surgeries, as follows: = 10, 11 to 19, 20 to 28, and = 29. RESULTS: The residents performed an average of 37 RP each. The average psa was 9.3 ng/mL and clinical stage T1c in 71% of the patients. The pathological stage was pT2 (73%, pT3 (23%, pT4 (4%, and 46% of the patients had a Gleason score 7 or higher. In all surgeries, the average operative time and estimated blood loss was 140 minutes and 488 mL. Overall, 7.2% of patients required blood transfusion, and 23% had positive surgical margins. CONCLUSION: During the initial RP learning curve, we found a significant reduction in the operative time; blood transfusion during the procedures and positive surgical margin rate were stable in our series.
Incorporating Experience Curves in Appliance Standards Analysis
Energy Technology Data Exchange (ETDEWEB)
Garbesi, Karina; Chan, Peter; Greenblatt, Jeffery; Kantner, Colleen; Lekov, Alex; Meyers, Stephen; Rosenquist, Gregory; Buskirk, Robert Van; Yang, Hung-Chia; Desroches, Louis-Benoit
2011-10-31
The technical analyses in support of U.S. energy conservation standards for residential appliances and commercial equipment have typically assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. There is, however, considerable evidence that this assumption does not reflect real market prices. Costs and prices generally fall in relation to cumulative production, a phenomenon known as experience and modeled by a fairly robust empirical experience curve. Using price data from the Bureau of Labor Statistics, and shipment data obtained as part of the standards analysis process, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These allow us to develop more representative appliance price projections than the assumption-based approach of constant prices. These experience curves were incorporated into recent energy conservation standards for these products. The impact on the national modeling can be significant, often increasing the net present value of potential standard levels in the analysis. In some cases a previously cost-negative potential standard level demonstrates a benefit when incorporating experience. These results imply that past energy conservation standards analyses may have undervalued the economic benefits of potential standard levels.
Microvascular Anastomosis: Proposition of a Learning Curve.
Mokhtari, Pooneh; Tayebi Meybodi, Ali; Benet, Arnau; Lawton, Michael T
2018-04-14
Learning to perform a microvascular anastomosis is one of the most difficult tasks in cerebrovascular surgery. Previous studies offer little regarding the optimal protocols to maximize learning efficiency. This failure stems mainly from lack of knowledge about the learning curve of this task. To delineate this learning curve and provide information about its various features including acquisition, improvement, consistency, stability, and recall. Five neurosurgeons with an average surgical experience history of 5 yr and without any experience in bypass surgery performed microscopic anastomosis on progressively smaller-caliber silastic tubes (Biomet, Palm Beach Gardens, Florida) during 24 consecutive sessions. After a 1-, 2-, and 8-wk retention interval, they performed recall test on 0.7-mm silastic tubes. The anastomoses were rated based on anastomosis patency and presence of any leaks. Improvement rate was faster during initial sessions compared to the final practice sessions. Performance decline was observed in the first session of working on a smaller-caliber tube. However, this rapidly improved during the following sessions of practice. Temporary plateaus were seen in certain segments of the curve. The retention interval between the acquisition and recall phase did not cause a regression to the prepractice performance level. Learning the fine motor task of microvascular anastomosis adapts to the basic rules of learning such as the "power law of practice." Our results also support the improvement of performance during consecutive sessions of practice. The objective evidence provided may help in developing optimized learning protocols for microvascular anastomosis.
Modeling Patterns of Activities using Activity Curves.
Dawadi, Prafulla N; Cook, Diane J; Schmitter-Edgecombe, Maureen
2016-06-01
Pervasive computing offers an unprecedented opportunity to unobtrusively monitor behavior and use the large amount of collected data to perform analysis of activity-based behavioral patterns. In this paper, we introduce the notion of an activity curve , which represents an abstraction of an individual's normal daily routine based on automatically-recognized activities. We propose methods to detect changes in behavioral routines by comparing activity curves and use these changes to analyze the possibility of changes in cognitive or physical health. We demonstrate our model and evaluate our change detection approach using a longitudinal smart home sensor dataset collected from 18 smart homes with older adult residents. Finally, we demonstrate how big data-based pervasive analytics such as activity curve-based change detection can be used to perform functional health assessment. Our evaluation indicates that correlations do exist between behavior and health changes and that these changes can be automatically detected using smart homes, machine learning, and big data-based pervasive analytics.
Statistical and biophysical aspects of survival curve
International Nuclear Information System (INIS)
Kellerer, A.M.
1980-01-01
Statistic fluctuation in a series of consequently taken survival curves of asynchronous cells of a hamster of the V79 line during X-ray irradiation, are considered. In each of the experiments fluctuations are close to those expected on the basis of the Poisson distribution. The fluctuation of cell sensitivity in different experiments of one series can reach 10%. The normalization of each experiment in mean values permits to obtain the ''idealized'' survival curve. The survival logarithm in this curve is proportional to the absorbed dose and its square only at low radiation doses. Such proportionality in V lab 79 cells in the late S-phase is observed at all doses. Using the microdosimetric approach, the distance where the interaction of radiolysis products or subinjury takes place to make the dependence of injury on the dose non-linear, is determined. In the case of interaction distances of 10-100 nm, the linear component is shown to become comparable in value with the linear injury component at doses of the order of several hundred rad only in the case, when the interaction distance is close to micrometre [ru
Wheelset curving guidance using H∞ control
Qazizadeh, Alireza; Stichel, Sebastian; Feyzmahdavian, Hamid Reza
2018-03-01
This study shows how to design an active suspension system for guidance of a rail vehicle wheelset in curve. The main focus of the study is on designing the controller and afterwards studying its effect on the wheel wear behaviour. The controller is designed based on the closed-loop transfer function shaping method and ? control strategy. The study discusses designing of the controller for both nominal and uncertain plants and considers both stability and performance. The designed controllers in Simulink are then applied to the vehicle model in Simpack to study the wheel wear behaviour in curve. The vehicle type selected for this study is a two-axle rail vehicle. This is because this type of vehicle is known to have very poor curving performance and high wheel wear. On the other hand, the relative simpler structure of this type of vehicle compared to bogie vehicles make it a more economic choice. Hence, equipping this type of vehicle with the active wheelset steering is believed to show high enough benefit to cost ratio to remain attractive to rail vehicle manufacturers and operators.
Numerical Characterization of Piezoceramics Using Resonance Curves
Directory of Open Access Journals (Sweden)
Nicolás Pérez
2016-01-01
Full Text Available Piezoelectric materials characterization is a challenging problem involving physical concepts, electrical and mechanical measurements and numerical optimization techniques. Piezoelectric ceramics such as Lead Zirconate Titanate (PZT belong to the 6 mm symmetry class, which requires five elastic, three piezoelectric and two dielectric constants to fully represent the material properties. If losses are considered, the material properties can be represented by complex numbers. In this case, 20 independent material constants are required to obtain the full model. Several numerical methods have been used to adjust the theoretical models to the experimental results. The continuous improvement of the computer processing ability has allowed the use of a specific numerical method, the Finite Element Method (FEM, to iteratively solve the problem of finding the piezoelectric constants. This review presents the recent advances in the numerical characterization of 6 mm piezoelectric materials from experimental electrical impedance curves. The basic strategy consists in measuring the electrical impedance curve of a piezoelectric disk, and then combining the Finite Element Method with an iterative algorithm to find a set of material properties that minimizes the difference between the numerical impedance curve and the experimental one. Different methods to validate the results are also discussed. Examples of characterization of some common piezoelectric ceramics are presented to show the practical application of the described methods.
Granados, I.; Calo, M.; Ramos, V.
2017-12-01
We developed a Matlab suite package (NDCP, Noisy Dispersion Curve Picking) that allows a full control over parameters to identify correctly group velocity dispersion curves in two types of datasets: correlograms between two stations or surface wave records from earthquakes. Using the frequency-time analysis (FTAN), the procedure to obtain the dispersion curves from records with a high noise level becomes difficult, and sometimes, the picked curve result in a misinterpreted character. For correlogram functions, obtained with cross-correlation of noise records or earthquake's coda, a non-homogeneous noise sources distribution yield to a non-symmetric Green's function (GF); to retrieve the complete information contained in there, NDCP allows to pick the dispersion curve in the time domain both in the causal and non-causal part of the GF. Then the picked dispersion curve is displayed on the FTAN diagram to in order to check if it matches with the maximum of the signal energy avoiding confusion with overtones or spike of noise. To illustrate how NDCP performs, we show exemple using: i) local correlograms functions obtained from sensors deployed into a volcanic caldera (Los Humeros, in Puebla, Mexico), ii) regional correlograms functions between two stations of the National Seismological Service (SSN, Servicio Sismológico Nacional in Spanish), and iii) surface wave seismic record for an earthquake located in the Pacific Ocean coast of Mexico and recorded by the SSN. This work is supported by the GEMEX project (Geothermal Europe-Mexico consortium).
Variation of curve number with storm depth
Banasik, K.; Hejduk, L.
2012-04-01
The NRCS Curve Number (known also as SCS-CN) method is well known as a tool in predicting flood runoff depth from small ungauged catchment. The traditional way of determination the CNs, based on soil characteristics, land use and hydrological conditions, seemed to have tendency to overpredict the floods in some cases. Over 30 year rainfall-runoff data, collected in two small (A=23.4 & 82.4 km2), lowland, agricultural catchments in Center of Poland (Banasik & Woodward 2010), were used to determine runoff Curve Number and to check a tendency of changing. The observed CN declines with increasing storm size, which according recent views of Hawkins (1993) could be classified as a standard response of watershed. The analysis concluded, that using CN value according to the procedure described in USDA-SCS Handbook one receives representative value for estimating storm runoff from high rainfall depths in the analyzes catchments. This has been confirmed by applying "asymptotic approach" for estimating the watershed curve number from the rainfall-runoff data. Furthermore, the analysis indicated that CN, estimated from mean retention parameter S of recorded events with rainfall depth higher than initial abstraction, is also approaching the theoretical CN. The observed CN, ranging from 59.8 to 97.1 and from 52.3 to 95.5, in the smaller and the larger catchment respectively, declines with increasing storm size, which has been classified as a standard response of watershed. The investigation demonstrated also changeability of the CN during a year, with much lower values during the vegetation season. Banasik K. & D.E. Woodward (2010). "Empirical determination of curve number for a small agricultural watrshed in Poland". 2nd Joint Federal Interagency Conference, Las Vegas, NV, June 27 - July 1, 2010 (http://acwi.gov/sos/pubs/2ndJFIC/Contents/10E_Banasik_ 28_02_10. pdf). Hawkins R. H. (1993). "Asymptotic determination of curve numbers from data". Journal of Irrigation and Drainage
Directory of Open Access Journals (Sweden)
Esteban Pérez-López
2014-11-01
Full Text Available Because of the importance of quantitative chemical analysis in research, quality control, sales of services and other areas of interest , and the limiting of some instrumental analysis methods for quantification with linear calibration curve, sometimes because the short linear dynamic ranges of the analyte, and sometimes by limiting the technique itself, is that there is a need to investigate a little more about the convenience of using quadratic curves for analytical quantification, which seeks demonstrate that it is a valid calculation model for chemical analysis instruments. To this was taken as an analysis method based on the technique and atomic absorption spectroscopy in particular a determination of magnesium in a sample of drinking water Tacares sector Northern Grecia, employing a nonlinear calibration curve and a curve specific quadratic behavior, which was compared with the test results obtained for the same analysis with a linear calibration curve. The results show that the methodology is valid for the determination referred to, with all confidence, since the concentrations are very similar, and as used hypothesis testing can be considered equal.
Ablation front rayleigh taylor dispersion curve in indirect drive
International Nuclear Information System (INIS)
Budil, K.S.; Lasinski, B.; Edwards, M.J.; Wan, A.S.; Remington, B.A.; Weber, S.V.; Glendinning, S.G.; Suter, L.; Stry, P.
2000-01-01
The Rayleigh-Taylor (RT) instability, which occurs when a lower-density fluid accelerates a higher-density layer, is common in nature. At an ablation front a sharp reduction in the growth rate of the instability at short wave-lengths can occur, in marked contrast to the classical case where growth rates are highest at the shortest wavelengths. Theoretical and numerical investigations of the ablative RT instability are numerous and differ considerably on the level of stabilization expected. We present here the results of a series of laser experiments designed to probe the roll-over and cutoff region of the ablation-front RT dispersion curve in indirect drive. Aluminum foils with imposed sinusoidal perturbations ranging in wavelength from 10 to 70 pm were ablatively accelerated with a radiation drive generated in a gold cylindrical hohlraum. A strong shock wave compresses the package followed by an ∼2 ns period of roughly constant acceleration and the experiment is diagnosed via face-on radiography. Perturbations with wavelengths (ge) 20 (micro)m experienced substantial growth during the acceleration phase while shorter wavelengths showed a sharp drop off in overall growth. These experimental results compared favorably to calculations with a 2-D radiation-hydrodynamics code, however, the growth is significantly affected by the rippled shock launched by the drive. We performed numerical simulations to elucidate the influence of the rippled shock wave on the eventual growth of the perturbations, allowing comparisons to the analytic model developed by Betti et al. This combination of experiments, simulations and analytic modeling illustrates the qualitative simplicity yet quantitative complexity of the compressible RT instability. We have measured the Rayleigh-Taylor (RT) dispersion curve for a radiatively-driven sample in a series of experiments on the Nova laser facility. Planar aluminum foils were ablatively-accelerated and the subsequent perturbation growth was
Quantitative Ultrasound for Measuring Obstructive Severity in Children with Hydronephrosis.
Cerrolaza, Juan J; Peters, Craig A; Martin, Aaron D; Myers, Emmarie; Safdar, Nabile; Linguraru, Marius George
2016-04-01
We define sonographic biomarkers for hydronephrotic renal units that can predict the necessity of diuretic nuclear renography. We selected a cohort of 50 consecutive patients with hydronephrosis of varying severity in whom 2-dimensional sonography and diuretic mercaptoacetyltriglycine renography had been performed. A total of 131 morphological parameters were computed using quantitative image analysis algorithms. Machine learning techniques were then applied to identify ultrasound based safety thresholds that agreed with the t½ for washout. A best fit model was then derived for each threshold level of t½ that would be clinically relevant at 20, 30 and 40 minutes. Receiver operating characteristic curve analysis was performed. Sensitivity, specificity and area under the receiver operating characteristic curve were determined. Improvement obtained by the quantitative imaging method compared to the Society for Fetal Urology grading system and the hydronephrosis index was statistically verified. For the 3 thresholds considered and at 100% sensitivity the specificities of the quantitative imaging method were 94%, 70% and 74%, respectively. Corresponding area under the receiver operating characteristic curve values were 0.98, 0.94 and 0.94, respectively. Improvement obtained by the quantitative imaging method over the Society for Fetal Urology grade and hydronephrosis index was statistically significant (p hydronephrosis can identify thresholds of clinically significant washout times with 100% sensitivity to decrease the number of diuretic renograms in up to 62% of children. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.
Quantitative secondary electron detection
Agrawal, Jyoti; Joy, David C.; Nayak, Subuhadarshi
2018-05-08
Quantitative Secondary Electron Detection (QSED) using the array of solid state devices (SSD) based electron-counters enable critical dimension metrology measurements in materials such as semiconductors, nanomaterials, and biological samples (FIG. 3). Methods and devices effect a quantitative detection of secondary electrons with the array of solid state detectors comprising a number of solid state detectors. An array senses the number of secondary electrons with a plurality of solid state detectors, counting the number of secondary electrons with a time to digital converter circuit in counter mode.
[Methods of quantitative proteomics].
Kopylov, A T; Zgoda, V G
2007-01-01
In modern science proteomic analysis is inseparable from other fields of systemic biology. Possessing huge resources quantitative proteomics operates colossal information on molecular mechanisms of life. Advances in proteomics help researchers to solve complex problems of cell signaling, posttranslational modification, structure and functional homology of proteins, molecular diagnostics etc. More than 40 various methods have been developed in proteomics for quantitative analysis of proteins. Although each method is unique and has certain advantages and disadvantages all these use various isotope labels (tags). In this review we will consider the most popular and effective methods employing both chemical modifications of proteins and also metabolic and enzymatic methods of isotope labeling.
Quantitative analysis of water heavy by NMR spectroscopy
International Nuclear Information System (INIS)
Gomez Gil, V.
1975-01-01
Nuclear Magnetic Resonance has been applied to a wide variety of quantitative problems. A typical example has been the determination of isotopic composition. In this paper two different analytical methods for the determination of water in deuterium oxide are described. The first one, employs acetonitril as an internal standard compound and in the second one calibration curve of signal integral curve versus amount of D 2 O is constructed. Both methods give results comparable to those of mass spectrometry of IR spectroscopy. (Author) 5 refs
Computer compensation for NMR quantitative analysis of trace components
International Nuclear Information System (INIS)
Nakayama, T.; Fujiwara, Y.
1981-01-01
A computer program has been written that determines trace components and separates overlapping components in multicomponent NMR spectra. This program uses the Lorentzian curve as a theoretical curve of NMR spectra. The coefficients of the Lorentzian are determined by the method of least squares. Systematic errors such as baseline/phase distortion are compensated and random errors are smoothed by taking moving averages, so that there processes contribute substantially to decreasing the accumulation time of spectral data. The accuracy of quantitative analysis of trace components has been improved by two significant figures. This program was applied to determining the abundance of 13C and the saponification degree of PVA
Quantitative Decision Support Requires Quantitative User Guidance
Smith, L. A.
2009-12-01
Is it conceivable that models run on 2007 computer hardware could provide robust and credible probabilistic information for decision support and user guidance at the ZIP code level for sub-daily meteorological events in 2060? In 2090? Retrospectively, how informative would output from today’s models have proven in 2003? or the 1930’s? Consultancies in the United Kingdom, including the Met Office, are offering services to “future-proof” their customers from climate change. How is a US or European based user or policy maker to determine the extent to which exciting new Bayesian methods are relevant here? or when a commercial supplier is vastly overselling the insights of today’s climate science? How are policy makers and academic economists to make the closely related decisions facing them? How can we communicate deep uncertainty in the future at small length-scales without undermining the firm foundation established by climate science regarding global trends? Three distinct aspects of the communication of the uses of climate model output targeting users and policy makers, as well as other specialist adaptation scientists, are discussed. First, a brief scientific evaluation of the length and time scales at which climate model output is likely to become uninformative is provided, including a note on the applicability the latest Bayesian methodology to current state-of-the-art general circulation models output. Second, a critical evaluation of the language often employed in communication of climate model output, a language which accurately states that models are “better”, have “improved” and now “include” and “simulate” relevant meteorological processed, without clearly identifying where the current information is thought to be uninformative and misleads, both for the current climate and as a function of the state of the (each) climate simulation. And thirdly, a general approach for evaluating the relevance of quantitative climate model output
Dose-response curves from incomplete data
International Nuclear Information System (INIS)
Groer, P.G.
1978-01-01
Frequently many different responses occur in populations (animal or human) exposed to ionizing radiation. To obtain a dose-response curve, the exposed population is first divided into sub-groups whose members received the same radiation dose. To estimate the response, the fraction of subjects in each sub-group that showed the particular response of interest is determined. These fractions are plotted against dose to give the dose-response curve. This procedure of plotting the fractions versus the radiation dose is not the correct way to estimate the time distribution for a particular response at the different dose levels. Other observed responses competed for the individuals in the exposed population and therefore prevented manifestation of the complete information on the response-time distribution for one specific response. Such data are called incomplete in the statistical literature. A procedure is described which uses the by now classical Kaplan-Meier estimator, to establish dose-response curves from incomplete data under the assumption that the different observed responses are statistically independent. It is demonstrated that there is insufficient information in the observed survival functions to estimate the time distribution for one particular response if the assumption of independence is dropped. In addition, it is not possible to determine from the data (i.e. type of response and when it occurred) whether or not the different response-time distributions are independent. However, it is possible to give sharp bounds between which the response has to lie. This implies that for incomplete data, only a 'dose-response band' can be established if independence of the competing responses cannot be assumed. Examples are given using actual data to illustrate the estimation procedures
van Dijk, R; van Assen, M; Vliegenthart, R; de Bock, G H; van der Harst, P; Oudkerk, M
2017-11-27
Stress cardiovascular magnetic resonance (CMR) perfusion imaging is a promising modality for the evaluation of coronary artery disease (CAD) due to high spatial resolution and absence of radiation. Semi-quantitative and quantitative analysis of CMR perfusion are based on signal-intensity curves produced during the first-pass of gadolinium contrast. Multiple semi-quantitative and quantitative parameters have been introduced. Diagnostic performance of these parameters varies extensively among studies and standardized protocols are lacking. This study aims to determine the diagnostic accuracy of semi- quantitative and quantitative CMR perfusion parameters, compared to multiple reference standards. Pubmed, WebOfScience, and Embase were systematically searched using predefined criteria (3272 articles). A check for duplicates was performed (1967 articles). Eligibility and relevance of the articles was determined by two reviewers using pre-defined criteria. The primary data extraction was performed independently by two researchers with the use of a predefined template. Differences in extracted data were resolved by discussion between the two researchers. The quality of the included studies was assessed using the 'Quality Assessment of Diagnostic Accuracy Studies Tool' (QUADAS-2). True positives, false positives, true negatives, and false negatives were subtracted/calculated from the articles. The principal summary measures used to assess diagnostic accuracy were sensitivity, specificity, andarea under the receiver operating curve (AUC). Data was pooled according to analysis territory, reference standard and perfusion parameter. Twenty-two articles were eligible based on the predefined study eligibility criteria. The pooled diagnostic accuracy for segment-, territory- and patient-based analyses showed good diagnostic performance with sensitivity of 0.88, 0.82, and 0.83, specificity of 0.72, 0.83, and 0.76 and AUC of 0.90, 0.84, and 0.87, respectively. In per territory
Arithmetic fundamental groups and moduli of curves
International Nuclear Information System (INIS)
Makoto Matsumoto
2000-01-01
This is a short note on the algebraic (or sometimes called arithmetic) fundamental groups of an algebraic variety, which connects classical fundamental groups with Galois groups of fields. A large part of this note describes the algebraic fundamental groups in a concrete manner. This note gives only a sketch of the fundamental groups of the algebraic stack of moduli of curves. Some application to a purely topological statement, i.e., an obstruction to the subjectivity of Johnson homomorphisms in the mapping class groups, which comes from Galois group of Q, is explained. (author)
Twisted vector bundles on pointed nodal curves
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
by identifying the points p1 and p2. If m ≥ 2, let R1,...,Rm−1 be m − 1 copies of the projective line P1 and let xi,yi be two distinct points in Ri. Let R be the nodal curve which arises from the union. R0 ⊔ R1 ⊔···⊔ Rm−1 ⊔ Rm by identifying p1 ∈ R0 and p2 ∈ Rm with x1 ∈ R1 and ym−1 ∈ Rm−1 respectively and by identifying ...
Task 4 Improvised Nuclear Device Response Curves
Energy Technology Data Exchange (ETDEWEB)
Alai, Maureen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Neuscamman, Stephanie [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2016-05-31
LLNL performed fallout and nuclear blast modeling for the 60 cities using the NARAC modeling system and predominant weather patterns determined in a previous Task 4 effort. LLNL performed model simulations and analyses to identify and provide response curves (expressed as two-dimensional contours) for radioactive fallout deposition, transport, population, and blast overpressure as a function of yield, weather, location and time. These contours can then be further combined and correlated with infrastructure and population databases to estimate city specific effects on KPFs such as impacted infrastructure and casualty rates.
ERROR VS REJECTION CURVE FOR THE PERCEPTRON
PARRONDO, JMR; VAN DEN BROECK, Christian
1993-01-01
We calculate the generalization error epsilon for a perceptron J, trained by a teacher perceptron T, on input patterns S that form a fixed angle arccos (J.S) with the student. We show that the error is reduced from a power law to an exponentially fast decay by rejecting input patterns that lie within a given neighbourhood of the decision boundary J.S = 0. On the other hand, the error vs. rejection curve epsilon(rho), where rho is the fraction of rejected patterns, is shown to be independent ...
Elliptic Tales Curves, Counting, and Number Theory
Ash, Avner
2012-01-01
Elliptic Tales describes the latest developments in number theory by looking at one of the most exciting unsolved problems in contemporary mathematics--the Birch and Swinnerton-Dyer Conjecture. The Clay Mathematics Institute is offering a prize of 1 million to anyone who can discover a general solution to the problem. In this book, Avner Ash and Robert Gross guide readers through the mathematics they need to understand this captivating problem. The key to the conjecture lies in elliptic curves, which are cubic equations in two variables. These equations may appear simple, yet they arise from
Learning curves for mutual information maximization
International Nuclear Information System (INIS)
Urbanczik, R.
2003-01-01
An unsupervised learning procedure based on maximizing the mutual information between the outputs of two networks receiving different but statistically dependent inputs is analyzed [S. Becker and G. Hinton, Nature (London) 355, 161 (1992)]. For a generic data model, I show that in the large sample limit the structure in the data is recognized by mutual information maximization. For a more restricted model, where the networks are similar to perceptrons, I calculate the learning curves for zero-temperature Gibbs learning. These show that convergence can be rather slow, and a way of regularizing the procedure is considered
The Bell Curve: An Essay Review
Directory of Open Access Journals (Sweden)
John C. Culbertson
1995-02-01
Full Text Available Occasionally a book out of academia will break from scholarly circles and enter into the mainstream market. On even rarer occasions, it will gain considerable notoriety before its initial publication. Richard Herrnstein and Charles Murray's The Bell Curve: Intelligence and Class Structure in American Life is such a book. Currently, it has entered the New York Times best- sellers list and appeared in most academic and mainstream periodical book reviews. Direct publicity for the book has also been strong. Although Herrnstein died September 24 of the past year, Murray has appeared on many popular television and radio talk shows.
Curves and tables of neutron cross sections
International Nuclear Information System (INIS)
Nakagawa, Tsuneo; Asami, Tetsuo; Yoshida, Tadashi
1990-07-01
Neutron cross-section curves from the Japanese Evaluated Nuclear Data Library version 3, JENDL-3, are presented in both graphical and tabular form for users in a wide range of application areas in the nuclear energy field. The contents cover cross sections for all the main reactions induced by neutrons with an energy below 20 MeV including; total, elastic scattering, capture, and fission, (n,n'), (n,2n), (n,3n), (n,α), (n,p) reactions. The 2200 m/s cross-section values, resonance integrals, and Maxwellian- and fission-spectrum averaged cross sections are also tabulated. (author)
Operators and higher genus mirror curves
Energy Technology Data Exchange (ETDEWEB)
Codesido, Santiago [Département de Physique Théorique et section de Mathématiques,Université de Genève,Genève, CH-1211 (Switzerland); Gu, Jie [Laboratoire de Physique Théorique de l’École Normale Supérieure,CNRS, PSL Research University,Sorbonne Universités, UPMC, 75005 Paris (France); Mariño, Marcos [Département de Physique Théorique et section de Mathématiques,Université de Genève,Genève, CH-1211 (Switzerland)
2017-02-17
We perform further tests of the correspondence between spectral theory and topological strings, focusing on mirror curves of genus greater than one with nontrivial mass parameters. In particular, we analyze the geometry relevant to the SU(3) relativistic Toda lattice, and the resolved ℂ{sup 3}/ℤ{sub 6} orbifold. Furthermore, we give evidence that the correspondence holds for arbitrary values of the mass parameters, where the quantization problem leads to resonant states. We also explore the relation between this correspondence and cluster integrable systems.
Localization of nonlinear excitations in curved waveguides
DEFF Research Database (Denmark)
Gaididei, Yu. B.; Christiansen, Peter Leth; Kevrekidis, P. G.
2005-01-01
numerical simulations of the nonlinear problem and in this case localized excitations are found to persist. We found also interesting relaxational dynamics. Analogies of the present problem in context related to atomic physics and particularly to Bose–Einstein condensation are discussed.......Motivated by the examples of a curved waveguide embedded in a photonic crystal and cold atoms moving in a waveguide created by a spatially inhomogeneous electromagnetic field, we examine the effects of geometry in a 'quantum channel' of parabolic form. Starting with the linear case we derive exact...
Electromagnetic wave propagating along a space curve
Lai, Meng-Yun; Wang, Yong-Long; Liang, Guo-Hua; Wang, Fan; Zong, Hong-Shi
2018-03-01
By using the thin-layer approach, we derive the effective equation for the electromagnetic wave propagating along a space curve. We find intrinsic spin-orbit, extrinsic spin-orbit, and extrinsic orbital angular-momentum and intrinsic orbital angular-momentum couplings induced by torsion, which can lead to geometric phase, spin, and orbital Hall effects. And we show the helicity inversion induced by curvature that can convert a right-handed circularly polarized electromagnetic wave into a left-handed polarized one, vice versa. Finally, we demonstrate that the gauge invariance of the effective dynamics is protected by the geometrically induced gauge potential.
Electron conductance in curved quantum structures
DEFF Research Database (Denmark)
Willatzen, Morten; Gravesen, Jens
2010-01-01
is computationally fast and provides direct (geometrical) parameter insight as regards the determination of the electron transmission coefficient. We present, as a case study, calculations of the electron conductivity of a helically shaped quantum-wire structure and discuss the influence of the quantum......A differential-geometry analysis is employed to investigate the transmission of electrons through a curved quantum-wire structure. Although the problem is a three-dimensional spatial problem, the Schrodinger equation can be separated into three general coordinates. Hence, the proposed method...
Photoelectic BV Light Curves of Algol and the Interpretations of the Light Curves
Directory of Open Access Journals (Sweden)
Ho-Il Kim
1985-06-01
Full Text Available Standardized B and V photoelectric light curves of Algol are made with the observations obtained during 1982-84 with the 40-cm and the 61-cm reflectors of Yonsei University Observatory. These light curves show asymmetry between ascending and descending shoulders. The ascending shoulder is 0.02 mag brighter than descending shoulder in V light curve and 0.03 mag in B light curve. These asymmetric light curves are interpreted as the result of inhomogeneous energy distribution on the surface of one star of the eclipsing pair rather than the result of gaseous stream flowing from KOIV to B8V star. The 180-year periodicity, so called great inequality, are most likely the result proposed by Kim et al. (1983 that the abrupt and discrete mass losses of cooler component may be the cause of this orbital change. The amount of mass loss deduced from these discrete period changes turned out to be of the order of 10^(-6 - 10^(-5 Msolar.
DEFF Research Database (Denmark)
Hallett, Andrew Hughes; Fiedler, Salomon; Kooths, Stefan
The notes in this compilation address the pros and cons associated with the extension of ECB quantitative easing programme of asset purchases. The notes have been requested by the Committee on Economic and Monetary Affairs as an input for the February 2017 session of the Monetary Dialogue....
Quantitative Moessbauer analysis
International Nuclear Information System (INIS)
Collins, R.L.
1978-01-01
The quantitative analysis of Moessbauer data, as in the measurement of Fe 3+ /Fe 2+ concentration, has not been possible because of the different mean square velocities (x 2 ) of Moessbauer nuclei at chemically different sites. A method is now described which, based on Moessbauer data at several temperatures, permits the comparison of absorption areas at (x 2 )=0. (Auth.)
Analysis of velocity planning interpolation algorithm based on NURBS curve
Zhang, Wanjun; Gao, Shanping; Cheng, Xiyan; Zhang, Feng
2017-04-01
To reduce interpolation time and Max interpolation error in NURBS (Non-Uniform Rational B-Spline) inter-polation caused by planning Velocity. This paper proposed a velocity planning interpolation algorithm based on NURBS curve. Firstly, the second-order Taylor expansion is applied on the numerator in NURBS curve representation with parameter curve. Then, velocity planning interpolation algorithm can meet with NURBS curve interpolation. Finally, simulation results show that the proposed NURBS curve interpolator meet the high-speed and high-accuracy interpolation requirements of CNC systems. The interpolation of NURBS curve should be finished.
Plasma flow in a curved magnetic field
International Nuclear Information System (INIS)
Lindberg, L.
1977-09-01
A beam of collisionless plasma is injected along a longitudinal magnetic field into a region of curved magnetic field. Two unpredicted phenomena are observed: The beam becomes deflected in the direction opposite to that in which the field is curved, and it contracts to a flat slab in the plane of curvature of the magnetic field. The phenomenon is of a general character and can be expected to occur in a very wide range of densities. The lower density limit is set by the condition for self-polarization, nm sub(i)/epsilon 0 B 2 >> 1 or, which is equivalent, c 2 /v 2 sub(A) >> 1, where c is the velocity of light, and v sup(A) the Alfven velocity. The upper limit is presumably set by the requirement ωsub(e)tau(e) >> 1. The phenomenon is likely to be of importance e.g. for injection of plasma into magnetic bottles and in space and solar physics. The paper illustrates the comlexity of plasma flow phenomena and the importance of close contact between experimental and theoretical work. (author)
Dirac equation on a curved surface
Energy Technology Data Exchange (ETDEWEB)
Brandt, F.T., E-mail: fbrandt@usp.br; Sánchez-Monroy, J.A., E-mail: antosan@usp.br
2016-09-07
The dynamics of Dirac particles confined to a curved surface is examined employing the thin-layer method. We perform a perturbative expansion to first-order and split the Dirac field into normal and tangential components to the surface. In contrast to the known behavior of second order equations like Schrödinger, Maxwell and Klein–Gordon, we find that there is no geometric potential for the Dirac equation on a surface. This implies that the non-relativistic limit does not commute with the thin-layer method. Although this problem can be overcome when second-order terms are retained in the perturbative expansion, this would preclude the decoupling of the normal and tangential degrees of freedom. Therefore, we propose to introduce a first-order term which rescues the non-relativistic limit and also clarifies the effect of the intrinsic and extrinsic curvatures on the dynamics of the Dirac particles. - Highlights: • The thin-layer method is employed to derive the Dirac equation on a curved surface. • A geometric potential is absent at least to first-order in the perturbative expansion. • The effects of the extrinsic curvature are included to rescue the non-relativistic limit. • The resulting Dirac equation is consistent with the Heisenberg uncertainty principle.
Modeling of alpha mass-efficiency curve
International Nuclear Information System (INIS)
Semkow, T.M.; Jeter, H.W.; Parsa, B.; Parekh, P.P.; Haines, D.K.; Bari, A.
2005-01-01
We present a model for efficiency of a detector counting gross α radioactivity from both thin and thick samples, corresponding to low and high sample masses in the counting planchette. The model includes self-absorption of α particles in the sample, energy loss in the absorber, range straggling, as well as detector edge effects. The surface roughness of the sample is treated in terms of fractal geometry. The model reveals a linear dependence of the detector efficiency on the sample mass, for low masses, as well as a power-law dependence for high masses. It is, therefore, named the linear-power-law (LPL) model. In addition, we consider an empirical power-law (EPL) curve, and an exponential (EXP) curve. A comparison is made of the LPL, EPL, and EXP fits to the experimental α mass-efficiency data from gas-proportional detectors for selected radionuclides: 238 U, 230 Th, 239 Pu, 241 Am, and 244 Cm. Based on this comparison, we recommend working equations for fitting mass-efficiency data. Measurement of α radioactivity from a thick sample can determine the fractal dimension of its surface
Some fundamental questions about R-curves
International Nuclear Information System (INIS)
Kolednik, O.
1992-01-01
With the help of two simple thought experiments it is demonstrated that there exist two physically different types of fracture toughness. The crack-growth toughness, which is identical to the Griffith crack growth resistance, R, is a measure of the non-reversible energy which is needed to produce an increment of new crack area. The size of R is reflected by the slopes of the R-curves commonly used. So an increasing J-Δa-curve does not mean that the crack-growth resistance increases. The fracture initiation toughness, J i , is a normalized total energy (related to the ligament area) which must be put into the specimen up to fracture initiation. Only for ideally brittle materials R and J i have equal sizes. For small-scale yielding a relationship exists between R and J i , ao a one-parameter description of fracture processes is applicable. For large-scale yielding R and J i are not strictly related and both parameters are necessary to describe the fracture process. (orig.) [de
Spatially varying dispersion to model breakthrough curves.
Li, Guangquan
2011-01-01
Often the water flowing in a karst conduit is a combination of contaminated water entering at a sinkhole and cleaner water released from the limestone matrix. Transport processes in the conduit are controlled by advection, mixing (dilution and dispersion), and retention-release. In this article, a karst transport model considering advection, spatially varying dispersion, and dilution (from matrix seepage) is developed. Two approximate Green's functions are obtained using transformation of variables, respectively, for the initial-value problem and for the boundary-value problem. A numerical example illustrates that mixing associated with strong spatially varying conduit dispersion can cause strong skewness and long tailing in spring breakthrough curves. Comparison of the predicted breakthrough curve against that measured from a dye-tracing experiment between Ames Sink and Indian Spring, Northwest Florida, shows that the conduit dispersivity can be as large as 400 m. Such a large number is believed to imply strong solute interaction between the conduit and the matrix and/or multiple flow paths in a conduit network. It is concluded that Taylor dispersion is not dominant in transport in a karst conduit, and the complicated retention-release process between mobile- and immobile waters may be described by strong spatially varying conduit dispersion. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.
Aspherical Supernovae: Effects on Early Light Curves
Afsariardchi, Niloufar; Matzner, Christopher D.
2018-04-01
Early light from core-collapse supernovae, now detectable in high-cadence surveys, holds clues to a star and its environment just before it explodes. However, effects that alter the early light have not been fully explored. We highlight the possibility of nonradial flows at the time of shock breakout. These develop in sufficiently nonspherical explosions if the progenitor is not too diffuse. When they do develop, nonradial flows limit ejecta speeds and cause ejecta–ejecta collisions. We explore these phenomena and their observational implications using global, axisymmetric, nonrelativistic FLASH simulations of simplified polytropic progenitors, which we scale to representative stars. We develop a method to track photon production within the ejecta, enabling us to estimate band-dependent light curves from adiabatic simulations. Immediate breakout emission becomes hidden as an oblique flow develops. Nonspherical effects lead the shock-heated ejecta to release a more constant luminosity at a higher, evolving color temperature at early times, effectively mixing breakout light with the early light curve. Collisions between nonradial ejecta thermalize a small fraction of the explosion energy; we will address emission from these collisions in a subsequent paper.
Melting curve of materials: theory versus experiments
International Nuclear Information System (INIS)
Alfe, D; Vocadlo, L; Price, G D; Gillan, M J
2004-01-01
A number of melting curves of various materials have recently been measured experimentally and calculated theoretically, but the agreement between different groups is not always good. We discuss here some of the problems which may arise in both experiments and theory. We also report the melting curves of Fe and Al calculated recently using quantum mechanics techniques, based on density functional theory with generalized gradient approximations. For Al our results are in very good agreement with both low pressure diamond-anvil-cell experiments (Boehler and Ross 1997 Earth Planet. Sci. Lett. 153 223, Haenstroem and Lazor 2000 J. Alloys Compounds 305 209) and high pressure shock wave experiments (Shaner et al 1984 High Pressure in Science and Technology ed Homan et al (Amsterdam: North-Holland) p 137). For Fe our results agree with the shock wave experiments of Brown and McQueen (1986 J. Geophys. Res. 91 7485) and Nguyen and Holmes (2000 AIP Shock Compression of Condensed Matter 505 81) and the recent diamond-anvil-cell experiments of Shen et al (1998 Geophys. Res. Lett. 25 373). Our results are at variance with the recent calculations of Laio et al (2000 Science 287 1027) and, to a lesser extent, with the calculations of Belonoshko et al (2000 Phys. Rev. Lett. 84 3638). The reasons for these disagreements are discussed
Handbook of elliptic and hyperelliptic curve cryptography
Cohen, Henri; Avanzi, Roberto; Doche, Christophe; Lange, Tanja; Nguyen, Kim; Vercauteren, Frederik
2005-01-01
… very comprehensive coverage of this vast subject area … a useful and essential treatise for anyone involved in elliptic curve algorithms … this book offers the opportunity to grasp the ECC technology with a diversified and comprehensive perspective. … This book will remain on my shelf for a long time and will land on my desk on many occasions, if only because the coverage of the issues common to factoring and discrete log cryptosystems is excellent.-IACR Book Reviews, June 2011… the book is designed for people who are working in the area and want to learn more about a specific issue. The chapters are written to be relatively independent so that readers can focus on the part of interest for them. Such readers will be grateful for the excellent index and extensive bibliography. … the handbook covers a wide range of topics and will be a valuable reference for researchers in curve-based cryptography. -Steven D. Galbraith, Mathematical Reviews, Issue 2007f.
Curved Piezoelectric Actuators for Stretching Optical Fibers
Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.
2008-01-01
Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.
Light Curve Variations of AR Lacertae
Directory of Open Access Journals (Sweden)
Il-Seong Nha
1991-12-01
Full Text Available Sixteen unitary Light curves of AR Lac in B and V are made at Yonsei University Observatory in the period of 1980-1988. Some overview findings of light variations are made. (1 The light variations outside eclipse follow none of the wave migration patterns reported by previous investigators. (2 Complicated shapes outside eclipse are apparently much reduced in the light curves of 1983-1984. This suggests that, in the future, AR Lac has a chance to attain a normal state with mo complicated interactions. (3 The depths of the primary and the secondary mid-eclipses are changing year-to-year. (4 The K0 star, the larger component, has brightened by 0.m14 V, while the G2 star has shown a fluctuation of about 0.m05 in V. (5 The B-V values at primary mid-eclipse have no correlation with the depth variations. (6 Independently of the increase of maximum brightness, the B-V colors in the non-eclipsed phases changed slightly over the years.
Critical Quantitative Inquiry in Context
Stage, Frances K.; Wells, Ryan S.
2014-01-01
This chapter briefly traces the development of the concept of critical quantitative inquiry, provides an expanded conceptualization of the tasks of critical quantitative research, offers theoretical explanation and justification for critical research using quantitative methods, and previews the work of quantitative criticalists presented in this…
Mechanism based evaluation of materials behavior and reference curves
International Nuclear Information System (INIS)
Toerroenen, K.; Saario, T.; Wallin, K.; Forsten, J.
1984-01-01
The safety assessment of nuclear pressure vessels and piping requires a quantitative estimation of defect growth by stable and unstable manner during service. This estimation is essential for determining whether the defect detected during inspection should be repaired or whether the size of the defect even after its expected growth is small enough to leave the integrity of the vessel unaffected. The most important stable defect growth mechanism is that of environmentally assisted cyclic crack growth. Recent results indicate that it is markedly affected by sulfur content and/or manganese sulfide morphology and distribution. This implies that an essential improvement in component safety has been gained by currently applied steelmaking practices, which result in extra low sulfur content, generally below 0.01 wt%, and in round shape and small size of inclusions, through, e.g., calcium treatment, hence considerably reducing the effect of environment on crack growth rate. This further implies that the ASME Section XI reference curves for environmentally accelerated cyclic crack growth are conservative for steels produced by current steelmaking practices. (orig./WL)
Schlösser, Tom P C; van Stralen, Marijn; Chu, Winnie C W; Lam, Tsz-Ping; Ng, Bobby K W; Vincken, Koen L; Cheng, Jack C Y; Castelein, René M
2016-01-01
Although much attention has been given to the global three-dimensional aspect of adolescent idiopathic scoliosis (AIS), the accurate three-dimensional morphology of the primary and compensatory curves, as well as the intervening junctional segments, in the scoliotic spine has not been described before. A unique series of 77 AIS patients with high-resolution CT scans of the spine, acquired for surgical planning purposes, were included and compared to 22 healthy controls. Non-idiopathic curves were excluded. Endplate segmentation and local longitudinal axis in endplate plane enabled semi-automatic geometric analysis of the complete three-dimensional morphology of the spine, taking inter-vertebral rotation, intra-vertebral torsion and coronal and sagittal tilt into account. Intraclass correlation coefficients for interobserver reliability were 0.98-1.00. Coronal deviation, axial rotation and the exact length discrepancies in the reconstructed sagittal plane, as defined per vertebra and disc, were analyzed for each primary and compensatory curve as well as for the junctional segments in-between. The anterior-posterior difference of spinal length, based on "true" anterior and posterior points on endplates, was +3.8% for thoracic and +9.4% for (thoraco)lumbar curves, while the junctional segments were almost straight. This differed significantly from control group thoracic kyphosis (-4.1%; P<0.001) and lumbar lordosis (+7.8%; P<0.001). For all primary as well as compensatory curves, we observed linear correlations between the coronal Cobb angle, axial rotation and the anterior-posterior length difference (r≥0.729 for thoracic curves; r≥0.485 for (thoraco)lumbar curves). Excess anterior length of the spine in AIS has been described as a generalized growth disturbance, causing relative anterior spinal overgrowth. This study is the first to demonstrate that this anterior overgrowth is not a generalized phenomenon. It is confined to the primary as well as the
A simple transformation for converting CW-OSL curves to LM-OSL curves
DEFF Research Database (Denmark)
Bulur, E.
2000-01-01
A simple mathematical transformation is introduced to convert from OSL decay curves obtained in the conventional way to those obtained using a linear modulation technique based on a linear increase of the stimulation light intensity during OSL measurement. The validity of the transformation...... was tested by the IR-stimulated luminescence curves from feldspars, recorded using both the conventional and the linear modulation techniques. The transformation was further applied to green-light-stimulated OSL from K and Na feldspars. (C) 2000 Elsevier Science Ltd. All rights reserved....
Some exercises in quantitative NMR imaging
International Nuclear Information System (INIS)
Bakker, C.J.G.
1985-01-01
The articles represented in this thesis result from a series of investigations that evaluate the potential of NMR imaging as a quantitative research tool. In the first article the possible use of proton spin-lattice relaxation time T 1 in tissue characterization, tumor recognition and monitoring tissue response to radiotherapy is explored. The next article addresses the question whether water proton spin-lattice relaxation curves of biological tissues are adequately described by a single time constant T 1 , and analyzes the implications of multi-exponentiality for quantitative NMR imaging. In the third article the use of NMR imaging as a quantitative research tool is discussed on the basis of phantom experiments. The fourth article describes a method which enables unambiguous retrieval of sign information in a set of magnetic resonance images of the inversion recovery type. The next article shows how this method can be adapted to allow accurate calculation of T 1 pictures on a pixel-by-pixel basis. The sixth article, finally, describes a simulation procedure which enables a straightforward determination of NMR imaging pulse sequence parameters for optimal tissue contrast. (orig.)
ON THE TOPOLOGY OF MECHANISMS DESIGNED FOR CURVES GENERATION
Directory of Open Access Journals (Sweden)
MEREUTA Elena
2008-07-01
Full Text Available The paper presents some mechanisms used for generating simple or complex curves. The mechanisms are shown in different positions and for some special curves the demonstrations are performed.
Potentiometric titration curves of aluminium salt solutions and its ...
African Journals Online (AJOL)
Potentiometric titration curves of aluminium salt solutions and its species conversion ... of aluminium salt solutions under the moderate slow rate of base injection. ... silicate radical, and organic acid radical on the titration curves and its critical ...
Curve of Spee and Its Relationship with Dentoskeletal Morphology
Directory of Open Access Journals (Sweden)
Prerna Raje Batham
2013-01-01
Conclusion: The curve of Spee is related to various dentoskeletal variables. Thus, the determination of this relationship is useful to assess the feasibility of leveling the curve of Spee by orthodontic treatment.
Path Integrals and Anomalies in Curved Space
International Nuclear Information System (INIS)
Louko, Jorma
2007-01-01
Bastianelli and van Nieuwenhuizen's monograph 'Path Integrals and Anomalies in Curved Space' collects in one volume the results of the authors' 15-year research programme on anomalies that arise in Feynman diagrams of quantum field theories on curved manifolds. The programme was spurred by the path-integral techniques introduced in Alvarez-Gaume and Witten's renowned 1983 paper on gravitational anomalies which, together with the anomaly cancellation paper by Green and Schwarz, led to the string theory explosion of the 1980s. The authors have produced a tour de force, giving a comprehensive and pedagogical exposition of material that is central to current research. The first part of the book develops from scratch a formalism for defining and evaluating quantum mechanical path integrals in nonlinear sigma models, using time slicing regularization, mode regularization and dimensional regularization. The second part applies this formalism to quantum fields of spin 0, 1/2, 1 and 3/2 and to self-dual antisymmetric tensor fields. The book concludes with a discussion of gravitational anomalies in 10-dimensional supergravities, for both classical and exceptional gauge groups. The target audience is researchers and graduate students in curved spacetime quantum field theory and string theory, and the aims, style and pedagogical level have been chosen with this audience in mind. Path integrals are treated as calculational tools, and the notation and terminology are throughout tailored to calculational convenience, rather than to mathematical rigour. The style is closer to that of an exceedingly thorough and self-contained review article than to that of a textbook. As the authors mention, the first part of the book can be used as an introduction to path integrals in quantum mechanics, although in a classroom setting perhaps more likely as supplementary reading than a primary class text. Readers outside the core audience, including this reviewer, will gain from the book a
The thermal curve of nuclear matter
International Nuclear Information System (INIS)
Ma, Y.G.; Peter, J.; Siwek, A.; Bocage, F.; Bougault, R.; Brou, R.; Colin, J.; Cussol, D.; Durand, D.; Genouin-Duhamel, E.; Gulminelli, F.; Lecolley, J.F.; Lefort, T.; Le Neindre, N.; Lopez, O.; Louvel, M.; Nguyen, A.D.; Steckmeyer, J.C.; Tamain, B.; Vient, E.
1997-01-01
Earlier measurements of nuclear matter thermal curve of liquid to gas phase transition presented two limitation: only one temperature measuring method was available and the mass number of the formed nuclei decreased from 190 to 50 when the excitation energy increased. To avoid these limitations experiments with the multidetector INDRA at GANIL were carried-out. Among the quasi-projectiles issued from the 36 Ar collisions at 52, 74, 95 A.MeV on the 58 Ni, nuclei of close masses were selected. The excitation energy was determined by the calorimetry of the charged products emitted by quasi-projectiles while the temperature was measured by three different methods. Very different apparent temperatures were obtained for the same excitation energy/nucleon. Only one curve displays a slope variation but no indication of plateau. With the quasi-projectiles obtained from the collisions of 129 Xe at 50 MeV/u on a 119 Sn target behaviors similar to those of 36 Ar were observed in the covered domain of excitation energy. To solve this puzzle and recover the initial temperatures of interest the only mean was to do a theoretical simulation in which one follows the de-excitation of the nuclei formed at different excitation energies and look for the thermal curve able to reproduce the observed temperatures. Two extreme possibilities were taken into account concerning the de-excitation process: either a sequential process established at E * /A≤ 3 MeV/u or a sudden multifragmentation in several hot fragments, most probably at E * /A≥ 10 MeV/u. In both cases it was possible to reproduce the whole set of experimental results concerning the 36 Ar projectile. The initial temperature increases steadily as a function of excitation energy showing no plateau or singular points. The results indicate that, being a system without external pressure, in its passage from the liquid phase to the gas phase the nucleus does not display necessarily a temperature plateau. Discussions on
Illusory Paschen curves associated with strongly electronegative gases
DEFF Research Database (Denmark)
McAllister, Iain Wilson
1991-01-01
Using analytical linear regression analysis, it is shown that, for a strongly electronegative gas, the (direct) breakdown voltage curve obtained with a moderately nonuniform field is effectively linear. For a strongly electronegative gas, breakdown voltage measurements made on a moderately...... nonuniform field test gap give rise to an apparently liner curve. The curve can be designated a Paschen curve, but the erroneous nature of this designation becomes apparent from a linear regression analysis of the experimental breakdown data...
Chen, Cathy; Overbeck, Ludger
2017-01-01
This volume provides practical solutions and introduces recent theoretical developments in risk management, pricing of credit derivatives, quantification of volatility and copula modeling. This third edition is devoted to modern risk analysis based on quantitative methods and textual analytics to meet the current challenges in banking and finance. It includes 14 new contributions and presents a comprehensive, state-of-the-art treatment of cutting-edge methods and topics, such as collateralized debt obligations, the high-frequency analysis of market liquidity, and realized volatility. The book is divided into three parts: Part 1 revisits important market risk issues, while Part 2 introduces novel concepts in credit risk and its management along with updated quantitative methods. The third part discusses the dynamics of risk management and includes risk analysis of energy markets and for cryptocurrencies. Digital assets, such as blockchain-based currencies, have become popular b ut are theoretically challenging...
Quantitative skeletal scintiscanning
International Nuclear Information System (INIS)
Haushofer, R.
1982-01-01
330 patients were examined by skeletal scintiscanning with sup(99m)Tc pyrophosphate and sup(99m)methylene diphosphonate in the years between 1977 and 1979. Course control examinations were carried out in 12 patients. The collective of patients presented with primary skeletal tumours, metastases, inflammatory and degenerative skeletal diseases. Bone scintiscanning combined with the ''region of interest'' technique was found to be an objective and reproducible technique for quantitative measurement of skeletal radioactivity concentrations. The validity of nuclear skeletal examinations can thus be enhanced as far as diagnosis, course control, and differential diagnosis are concerned. Quantitative skeletal scintiscanning by means of the ''region of interest'' technique has opened up a new era in skeletal diagnosis by nuclear methods. (orig./MG) [de
Quantitative FDG in depression
Energy Technology Data Exchange (ETDEWEB)
Chua, P.; O`Keefe, G.J.; Egan, G.F.; Berlangieri, S.U.; Tochon-Danguy, H.J.; Mckay, W.J.; Morris, P.L.P.; Burrows, G.D. [Austin Hospital, Melbourne, VIC (Australia). Dept of Psychiatry and Centre for PET
1998-03-01
Full text: Studies of regional cerebral glucose metabolism (rCMRGlu) using positron emission tomography (PET) in patients with affective disorders have consistently demonstrated reduced metabolism in the frontal regions. Different quantitative and semi-quantitative rCMRGlu regions of interest (ROI) comparisons, e.g. absolute metabolic rates, ratios of dorsolateral prefrontal cortex (DLPFC) to ipsilateral hemisphere cortex, have been reported. These studies suffered from the use of a standard brain atlas to define ROls, whereas in this case study, the individual``s magnetic resonance imaging (MRI) scan was registered with the PET scan to enable accurate neuroanatomical ROI definition for the subject. The patient is a 36-year-old female with a six-week history of major depression (HAM-D = 34, MMSE = 28). A quantitative FDG PET study and an MRI scan were performed. Six MRI-guided ROls (DLPFC, PFC, whole hemisphere) were defined. The average rCMRGlu in the DLPFC (left = 28.8 + 5.8 mol/100g/min; right = 25.6 7.0 mol/100g/min) were slightly reduced compared to the ipsilateral hemispherical rate (left = 30.4 6.8 mol/100g/min; right = 29.5 7.2 mol/100g/min). The ratios of DLPFC to ipsilateral hemispheric rate were close to unity (left = 0.95 0.29; right 0.87 0.32). The right to left DLPFC ratio did not show any significant asymmetry (0.91 0.30). These results do not correlate with earlier published results reporting decreased left DLPFC rates compared to right DLPFC, although our results will need to be replicated with a group of depressed patients. Registration of PET and MRI studies is necessary in ROI-based quantitative FDG PET studies to allow for the normal anatomical variation among individuals, and thus is essential for accurate comparison of rCMRGlu between individuals.
Quantitative FDG in depression
International Nuclear Information System (INIS)
Chua, P.; O'Keefe, G.J.; Egan, G.F.; Berlangieri, S.U.; Tochon-Danguy, H.J.; Mckay, W.J.; Morris, P.L.P.; Burrows, G.D.
1998-01-01
Full text: Studies of regional cerebral glucose metabolism (rCMRGlu) using positron emission tomography (PET) in patients with affective disorders have consistently demonstrated reduced metabolism in the frontal regions. Different quantitative and semi-quantitative rCMRGlu regions of interest (ROI) comparisons, e.g. absolute metabolic rates, ratios of dorsolateral prefrontal cortex (DLPFC) to ipsilateral hemisphere cortex, have been reported. These studies suffered from the use of a standard brain atlas to define ROls, whereas in this case study, the individual''s magnetic resonance imaging (MRI) scan was registered with the PET scan to enable accurate neuroanatomical ROI definition for the subject. The patient is a 36-year-old female with a six-week history of major depression (HAM-D = 34, MMSE = 28). A quantitative FDG PET study and an MRI scan were performed. Six MRI-guided ROls (DLPFC, PFC, whole hemisphere) were defined. The average rCMRGlu in the DLPFC (left = 28.8 + 5.8 mol/100g/min; right = 25.6 7.0 mol/100g/min) were slightly reduced compared to the ipsilateral hemispherical rate (left = 30.4 6.8 mol/100g/min; right = 29.5 7.2 mol/100g/min). The ratios of DLPFC to ipsilateral hemispheric rate were close to unity (left = 0.95 0.29; right 0.87 0.32). The right to left DLPFC ratio did not show any significant asymmetry (0.91 0.30). These results do not correlate with earlier published results reporting decreased left DLPFC rates compared to right DLPFC, although our results will need to be replicated with a group of depressed patients. Registration of PET and MRI studies is necessary in ROI-based quantitative FDG PET studies to allow for the normal anatomical variation among individuals, and thus is essential for accurate comparison of rCMRGlu between individuals
Nonlinear Growth Curves in Developmental Research
Grimm, Kevin J.; Ram, Nilam; Hamagami, Fumiaki
2011-01-01
Developmentalists are often interested in understanding change processes and growth models are the most common analytic tool for examining such processes. Nonlinear growth curves are especially valuable to developmentalists because the defining characteristics of the growth process such as initial levels, rates of change during growth spurts, and asymptotic levels can be estimated. A variety of growth models are described beginning with the linear growth model and moving to nonlinear models of varying complexity. A detailed discussion of nonlinear models is provided, highlighting the added insights into complex developmental processes associated with their use. A collection of growth models are fit to repeated measures of height from participants of the Berkeley Growth and Guidance Studies from early childhood through adulthood. PMID:21824131
Environmental management by the learning curve
International Nuclear Information System (INIS)
Fehr, M.
2003-01-01
This is a futuristic appreciation of waste management challenges and their solution by means of good management models. A literature review, administrative initiatives, research results, and experiences from practice are combined in this study to render an evolutionary picture of the change in paradigm relative to municipal solid waste possible to occur between 2000 and 2025. The principal stages of progress in the 25 years studied were: the correct characterization of municipal solid waste as a function of geographical location and recycling potential, the divided collection model and its corresponding learning curve, correct opportunity cost accounting tools, and the generally admitted and accepted changeover of municipal solid waste treatment from a technical to a management problem. It is reported that as a result of this progress, the municipal landfill is a species in extinction. Regional landfills with long life spans are the rule in 2025
Topological Sound and Flocking on Curved Surfaces
Directory of Open Access Journals (Sweden)
Suraj Shankar
2017-09-01
Full Text Available Active systems on curved geometries are ubiquitous in the living world. In the presence of curvature, orientationally ordered polar flocks are forced to be inhomogeneous, often requiring the presence of topological defects even in the steady state because of the constraints imposed by the topology of the underlying surface. In the presence of spontaneous flow, the system additionally supports long-wavelength propagating sound modes that get gapped by the curvature of the underlying substrate. We analytically compute the steady-state profile of an active polar flock on a two-sphere and a catenoid, and show that curvature and active flow together result in symmetry-protected topological modes that get localized to special geodesics on the surface (the equator or the neck, respectively. These modes are the analogue of edge states in electronic quantum Hall systems and provide unidirectional channels for information transport in the flock, robust against disorder and backscattering.
Determination of water retention curves of concrete
International Nuclear Information System (INIS)
Villar, M.V.; Romero, F.J.
2015-01-01
The water retention curves of concrete and mortar obtained with two different techniques and following wetting and drying paths were determined. The material was the same used to manufacture the disposal cells of the Spanish surface facility of El Cabril. The water retention capacity of mortar is clearly higher than that of concrete when expressed as gravimetric water content, but the difference reduces when it is expressed as degree of saturation. Hysteresis between wetting and drying was observed for both materials, particularly for mortar. The tests went on for very long periods of time, and concerns about the geochemical, mineralogical and porosity changes occurred in the materials during the determinations (changes in dry mass, grain density, samples volume) and their repercussion on the results obtained (water content and degree of saturation computation) were raised. Also, the fact of having used techniques applying total and matrix suction could have affected the results. (authors)
Introduction to curved rotary tomographic apparatus 'TOMOREX'
International Nuclear Information System (INIS)
Kubota, Kazuo; Shinojima, Masayasu; Kohirasawa, Hideo; Tokui, Mitsuru
1980-01-01
In recent years, panorama X-ray photographic method is widely used for the X-ray diagnosis of teeth, jawbones and faces. One type based on the principle of tomography is curved surface rotary tomographic method utilizing fine-gap X-ray beam. With the synchronous rotation of an X-ray tube and a photographic film around a face, describing a U-shaped tomographic plane along a dental arch, an upper or lower jawbone is photographed. In the ''TOMOREX'' belonging to this type, is different tomographic planes are available, so that by selecting any position in advance, the part can be photographed. Furthermore, patients can be subjected to examination as laid on a stretcher. The mechanism and equipment, and the photographic method for eye sockets, cheekbones, upper jaw cavities and stereoscopic images are described. (J.P.N.)
FUZZY ACCEPTANCE SAMPLING AND CHARACTERISTIC CURVES
Directory of Open Access Journals (Sweden)
Ebru Turano?lu
2012-02-01
Full Text Available Acceptance sampling is primarily used for the inspection of incoming or outgoing lots. Acceptance sampling refers to the application of specific sampling plans to a designated lot or sequence of lots. The parameters of acceptance sampling plans are sample sizes and acceptance numbers. In some cases, it may not be possible to define acceptance sampling parameters as crisp values. These parameters can be expressed by linguistic variables. The fuzzy set theory can be successfully used to cope with the vagueness in these linguistic expressions for acceptance sampling. In this paper, the main distributions of acceptance sampling plans are handled with fuzzy parameters and their acceptance probability functions are derived. Then the characteristic curves of acceptance sampling are examined under fuzziness. Illustrative examples are given.
Two R curves for partially stabilized zirconia
International Nuclear Information System (INIS)
Rose, L.R.F.; Swain, M.V.
1986-01-01
The enhanced fracture toughness due to stress-induced transformation can be explained from two view points: (1) the increase can be attributed to the need to supply a work of transformation, or (2) the transformation can be considered to result in internal stresses which oppose crack opening. Experimental results for magnesia-partially-stabilized zirconia are presented for the two experimental measures of toughness corresponding to these two viewpoints, namely (1) the specific work of fracture, R, and (2) the nominal stress intensity factor, K/sup R/. It is observed that these two measures are not equivalent during the initial stage of R-curve behavior, prior to reaching steady-state cracking. The theoretical reason for this difference is discussed. In particular, it is noted that the usual definition for the crack extension force does not correspond to the experimentally measured work of fracture in the presence of stress-induced (or pre-existing) sources of internal stress
Analytical extension of curved shock theory
Emanuel, G.
2018-03-01
Curved shock theory (CST) is limited to shock waves in a steady, two-dimensional or axisymmetric (2-Ax) flow of a perfect gas. A unique feature of CST is its use of intrinsic coordinates that result in an elegant and useful formulation for flow properties just downstream of a shock. For instance, the downstream effect of upstream vorticity, shock wave curvature, and the upstream pressure gradient along a streamline is established. There have been several attempts to extend CST, as mentioned in the text. Removal of the steady, 2-Ax, and perfect gas limitations, singly or in combination, requires an appropriate formulation of the shock wave's jump relations and the intrinsic coordinate Euler equations. Issues discussed include flow plane versus osculating plane, unsteady flow, vorticity, an imperfect gas, etc. The extension of CST utilizes concepts from differential geometry, such as the osculating plane, streamline torsion, and the Serret-Frenet equations.
Monroe, TalaWanda R.
2017-08-01
The spectrophotometric white dwarf G191-B2B will be observed with the E140M grating to obtain an updated set of sensitivity curves for this highly used mode. Spectroscopic sensitivity monitoring observations of BD+284211 have shown that the blaze function shapes have changed since SM4 and now limit the relative photometric flux accuracy of 14 of 43 E140M spectral orders to 5-10% at the edges. The blaze function shape changes have hindered attempts to determine the post-SM4 temporal blaze function shifts for this grating. Given the popularity of this unique FUV mode, with almost full simultaneous coverage of 1144 to 1710 A in a single observation, and consideration of the STIS archival legacy, we request 1 orbit to re-observe G191-B2B with the E140/1425 setting.
Radiant absorption characteristics of corrugated curved tubes
Directory of Open Access Journals (Sweden)
Đorđević Milan Lj.
2017-01-01
Full Text Available The utilization of modern paraboloidal concentrators for conversion of solar radiation into heat energy requires the development and implementation of compact and efficient heat absorbers. Accurate estimation of geometry influence on absorption characteristics of receiver tubes is an important step in this process. This paper deals with absorption characteristics of heat absorber made of spirally coiled tubes with transverse circular corrugations. Detailed 3-D surface-to-surface Hemicube method was applied to compare radiation performances of corrugated and smooth curved tubes. The numerical results were obtained by varying the tube curvature ratio and incident radiant heat flux intensity. The details of absorption efficiency of corrugated tubes and the effect of curvature on absorption properties for both corrugated and smooth tubes were presented. The results may have significance to further analysis of highly efficient heat absorbers exposed to concentrated radiant heating. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 42006
Magnetic response of certain curved graphitic geometries
International Nuclear Information System (INIS)
Wang, L.; Davids, P.S.; Saxena, A.; Bishop, A.R.
1992-01-01
The quasi-particle energy spectra associated with some members of buckyfamily (curved graphitic geometries), in particular C 50 , C 60 , C 70 and related fullerenes as well as coaxial helical microtubules of graphite, are obtained analytically within the mean-field approximation. These energy spectra are then used to calculate various response functions. Specifically, we calculate the specific heat, magnetization and magnetic susceptibility in the presence of an external magnetic field at low temperatures. For a single microtubule an extra peak superimposed on the first de Haas van Alphen (dHvA) oscillation in magnetic susceptibility is found in the 50--170 Tesla range depending on the radius which is possibly accessible in special (explosive flux compression) experiments. Finally, we point to important potential applications of these novel mesoscopic structures in nanotechnology
Nonequilibrium recombination after a curved shock wave
Wen, Chihyung; Hornung, Hans
2010-02-01
The effect of nonequilibrium recombination after a curved two-dimensional shock wave in a hypervelocity dissociating flow of an inviscid Lighthill-Freeman gas is considered. An analytical solution is obtained with the effective shock values derived by Hornung (1976) [5] and the assumption that the flow is ‘quasi-frozen’ after a thin dissociating layer near the shock. The solution gives the expression of dissociation fraction as a function of temperature on a streamline. A rule of thumb can then be provided to check the validity of binary scaling for experimental conditions and a tool to determine the limiting streamline that delineates the validity zone of binary scaling. The effects on the nonequilibrium chemical reaction of the large difference in free stream temperature between free-piston shock tunnel and equivalent flight conditions are discussed. Numerical examples are presented and the results are compared with solutions obtained with two-dimensional Euler equations using the code of Candler (1988) [10].
Modelling critical NDVI curves in perennial ryegrass
DEFF Research Database (Denmark)
Gislum, R; Boelt, B
2010-01-01
The use of optical sensors to measure canopy reflectance and calculate crop index as e.g. normalized difference vegetation index (NDVI) is widely used in agricultural crops, but has so far not been implemented in herbage seed production. The present study has the purpose to develop a critical...... NDVI curve where the critical NDVI, defined as the minimum NDVI obtained to achieve a high seed yield, will be modelled during the growing season. NDVI measurements were made at different growing degree days (GDD) in a three year field experiment where different N application rates were applied....... There was a clear maximum in the correlation coefficient between seed yield and NDVI in the period from approximately 700 to 900 GDD. At this time there was an exponential relationship between NDVI and seed yield where highest seed yield were at NDVI ~0.9. Theoretically the farmers should aim for an NDVI of 0...
Black hole entropy, curved space and monsters
International Nuclear Information System (INIS)
Hsu, Stephen D.H.; Reeb, David
2008-01-01
We investigate the microscopic origin of black hole entropy, in particular the gap between the maximum entropy of ordinary matter and that of black holes. Using curved space, we construct configurations with entropy greater than the area A of a black hole of equal mass. These configurations have pathological properties and we refer to them as monsters. When monsters are excluded we recover the entropy bound on ordinary matter S 3/4 . This bound implies that essentially all of the microstates of a semiclassical black hole are associated with the growth of a slightly smaller black hole which absorbs some additional energy. Our results suggest that the area entropy of black holes is the logarithm of the number of distinct ways in which one can form the black hole from ordinary matter and smaller black holes, but only after the exclusion of monster states
Zero-point field in curved spaces
International Nuclear Information System (INIS)
Hacyan, S.; Sarmiento, A.; Cocho, G.; Soto, F.
1985-01-01
Boyer's conjecture that the thermal effects of acceleration are manifestations of the zero-point field is further investigated within the context of quantum field theory in curved spaces. The energy-momentum current for a spinless field is defined rigorously and used as the basis for investigating the energy density observed in a noninertial frame. The following examples are considered: (i) uniformly accelerated observers, (ii) two-dimensional Schwarzschild black holes, (iii) the Einstein universe. The energy spectra which have been previously calculated appear in the present formalism as an additional contribution to the energy of the zero-point field, but particle creation does not occur. It is suggested that the radiation produced by gravitational fields or by acceleration is a manifestation of the zero-point field and of the same nature (whether real or virtual)
Explosions and light curves of supernovae
International Nuclear Information System (INIS)
Gaffet, B.
1975-01-01
The models developed to explain supernovae explosions are reviewed. The first one is thermonuclear explosion (simple or preceded by an implosion phase); the neutrino emission which results of such an explosion can have an important dynamical effect, according as the star is opaque or transparent to them; another theory involves the radiation pressure of the pulsar which is formed in the center of the star. The origin of the supernovae brightness is also uncertain: the initial heat due to the explosion does not seem to be sufficient; the brightness can result from the diffusion of the heat through the ejected matter or can be transported more rapidly by a shock wave. A model in which the heat is produced by the pulsar seems compatible with most observations (shapes of the brightness curves and the continuum spectra, expansion velocities, temperature and luminosity at the peak, total kinetic energy) [fr
Curved laser microjet in near field.
Kotlyar, Victor V; Stafeev, Sergey S; Kovalev, Alexey A
2013-06-20
With the use of the finite-difference time-domain-based simulation and a scanning near-field optical microscope that has a metal cantilever tip, the diffraction of a linearly polarized plane wave of wavelength λ by a glass corner step of height 2λ is shown to generate a low divergence laser jet of a root-parabolic form: over a distance of 4.7λ on the optical axis, the beam path is shifted by 2.1λ. The curved laser jet of the FWHM length depth of focus=9.5λ has the diameter FWHM=1.94λ over the distance 5.5λ, and the intensity maximum is 5 times higher than the incident wave intensity. The discrepancy between the analytical and the experimental results amounts to 11%.
Prediction of long-term creep curves
International Nuclear Information System (INIS)
Oikawa, Hiroshi; Maruyama, Kouichi
1992-01-01
This paper aims at discussing how to predict long-term irradiation enhanced creep properties from short-term tests. The predictive method based on the θ concept was examined by using creep data of ferritic steels. The method was successful in predicting creep curves including the tertiary creep stage as well as rupture lifetimes. Some material constants involved in the method are insensitive to the irradiation environment, and their values obtained in thermal creep are applicable to irradiation enhanced creep. The creep mechanisms of most engineering materials definitely change at the athermal yield stress in the non-creep regime. One should be aware that short-term tests must be carried out at stresses lower than the athermal yield stress in order to predict the creep behavior of structural components correctly. (orig.)
Topological Sound and Flocking on Curved Surfaces
Shankar, Suraj; Bowick, Mark J.; Marchetti, M. Cristina
2017-07-01
Active systems on curved geometries are ubiquitous in the living world. In the presence of curvature, orientationally ordered polar flocks are forced to be inhomogeneous, often requiring the presence of topological defects even in the steady state because of the constraints imposed by the topology of the underlying surface. In the presence of spontaneous flow, the system additionally supports long-wavelength propagating sound modes that get gapped by the curvature of the underlying substrate. We analytically compute the steady-state profile of an active polar flock on a two-sphere and a catenoid, and show that curvature and active flow together result in symmetry-protected topological modes that get localized to special geodesics on the surface (the equator or the neck, respectively). These modes are the analogue of edge states in electronic quantum Hall systems and provide unidirectional channels for information transport in the flock, robust against disorder and backscattering.
Maturation curves of sweet sorghum genotypes
Directory of Open Access Journals (Sweden)
Renan Silva e Souza
2016-02-01
Full Text Available ABSTRACT Sweet sorghum [Sorghum bicolor (L. Moench] stands out as a complementary crop to sugarcane Saccharum spp. for the production of ethanol, since it has juicy stems with directly fermentable sugars. Due to this fact, there is a need for the analysis of sweet sorghum properties in order to meet the agro-industry demand. This work aimed to develop and study the maturation curves of seven sweet sorghum cultivars in ten harvest dates. The results showed a significant difference between cultivars and harvest dates for all parameters analysed (p≤0.01. Regarding the sugar content, the cultivars BRS508, XBWS80147 and CMSX629 showed the highest means for the total reducing sugars (TRS and recoverable sugar (RS. In the production of ethanol per tonne of biomass (EP, the cultivars BRS508 and CMSX629 presented the best results.
Curved VPH gratings for novel spectrographs
Clemens, J. Christopher; O'Donoghue, Darragh; Dunlap, Bart H.
2014-07-01
The introduction of volume phase holographic (VPH) gratings into astronomy over a decade ago opened new possibilities for instrument designers. In this paper we describe an extension of VPH grating technology that will have applications in astronomy and beyond: curved VPH gratings. These devices can disperse light while simultaneously correcting aberrations. We have designed and manufactured two different kinds of convex VPH grating prototypes for use in off-axis reflecting spectrographs. One type functions in transmission and the other in reflection, enabling Offnerstyle spectrographs with the high-efficiency and low-cost advantages of VPH gratings. We will discuss the design process and the tools required for modelling these gratings along with the recording layout and process steps required to fabricate them. We will present performance data for the first convex VPH grating produced for an astronomical spectrograph.
Nonlinear gravitons and curved twistor theory
International Nuclear Information System (INIS)
Penrose, R.
1976-01-01
A new approach to the quantization of general relativity is suggested in which a state consisting of just one graviton can be described, but in a way which involves both the curvature and nonlinearities of Einstein's theory. It is felt that this approach can be justified solely on its own merits but it also receives striking encouragement from another direction: a surprising mathematical result enables one to construct the general such nonlinear gravitation state from a curved twistor space, the construction being given in terms of one arbitrary holomorphic function of three complex variables. In this way, the approach fits naturally into the general twistor program for the description of quantized fields. (U.K.)
Developing an empirical Environmental Kuznets Curve
Directory of Open Access Journals (Sweden)
Ferry Purnawan
2015-04-01
Full Text Available This study aims to develop a model of Environmental Kuznets Curve (EKC that relates between environmental pollution level and the prosperity level in Tangerang City. The method uses two models of pooled data regression technique namely, Random Effect Model (REM, and Fixed Effects Model (FEM both quadratic and cubic. The period of observation is 2002-2012. The results suggest that relationship between per capita income and the level of environment quality, reflected as the BOD concentration (Oxygen Biological damage and COD (Chemical Oxygen Damage can be explained by the quadratic FEM model and follow the EKC hypothesis even though the turning point is not identified.
Oil exploitation and the environmental Kuznets curve
International Nuclear Information System (INIS)
Esmaeili, Abdoulkarim; Abdollahzadeh, Negar
2009-01-01
This study refers to a panel estimation of an environmental Kuznets curve (EKC) for oil to determine the factors most affecting oil exploitation in 38 oil-producing countries during 1990-2000. Control variables such as oil reserves, oil price, population, political rights, and the Gini index were used to determine its contribution to the main EKC model. The empirical results fully support the existence of an EKC for oil exploitation. Furthermore, the result indicates that the proved oil reserves has a significant and positive role in oil production, but oil price and population do not significantly affect crude oil production. Also, increased freedoms and a better income distribution will reduce the rate of oil exploitation. Thus, policies aiming at enhancing democratic society and better income distribution would be more compatible with sustainability. (author)
Oil exploitation and the environmental Kuznets curve
Energy Technology Data Exchange (ETDEWEB)
Esmaeili, Abdoulkarim; Abdollahzadeh, Negar [Department of Agricultural Economics, College of Agriculture, Shiraz University, Shiraz, Fars (Iran)
2009-01-15
This study refers to a panel estimation of an environmental Kuznets curve (EKC) for oil to determine the factors most affecting oil exploitation in 38 oil-producing countries during 1990-2000. Control variables such as oil reserves, oil price, population, political rights, and the Gini index were used to determine its contribution to the main EKC model. The empirical results fully support the existence of an EKC for oil exploitation. Furthermore, the result indicates that the proved oil reserves has a significant and positive role in oil production, but oil price and population do not significantly affect crude oil production. Also, increased freedoms and a better income distribution will reduce the rate of oil exploitation. Thus, policies aiming at enhancing democratic society and better income distribution would be more compatible with sustainability. (author)
Comparing kinetic curves in liquid chromatography
Kurganov, A. A.; Kanat'eva, A. Yu.; Yakubenko, E. E.; Popova, T. P.; Shiryaeva, V. E.
2017-01-01
Five equations for kinetic curves which connect the number of theoretical plates N and time of analysis t 0 for five different versions of optimization, depending on the parameters being varied (e.g., mobile phase flow rate, pressure drop, sorbent grain size), are obtained by means of mathematical modeling. It is found that a method based on the optimization of a sorbent grain size at fixed pressure is most suitable for the optimization of rapid separations. It is noted that the advantages of the method are limited by an area of relatively low efficiency, and the advantage of optimization is transferred to a method based on the optimization of both the sorbent grain size and the drop in pressure across a column in the area of high efficiency.
Medical learning curves and the Kantian ideal.
Le Morvan, P; Stock, B
2005-09-01
A hitherto unexamined problem for the "Kantian ideal" that one should always treat patients as ends in themselves, and never only as a means to other ends, is explored in this paper. The problem consists of a prima facie conflict between this Kantian ideal and the reality of medical practice. This conflict arises because, at least presently, medical practitioners can only acquire certain skills and abilities by practising on live, human patients, and given the inevitability and ubiquity of learning curves, this learning requires some patients to be treated only as a means to this end. A number of ways of attempting to establish the compatibility of the Kantian Ideal with the reality of medical practice are considered. Each attempt is found to be unsuccessful. Accordingly, until a way is found to reconcile them, we conclude that the Kantian ideal is inconsistent with the reality of medical practice.
Quantum electrodynamics in curved space-time
International Nuclear Information System (INIS)
Buchbinder, I.L.; Gitman, D.M.; Fradkin, E.S.
1981-01-01
The lagrangian of quantum electrodynamics in curved space-time is constructed and the interaction picture taking into account the external gravitational field exactly is introduced. The transform from the Heisenberg picture to the interaction picture is carried out in a manifestly covariant way. The properties of free spinor and electromagnetic quantum fields are discussed and conditions under which initial and final creation and annihilation operators are connected by unitarity transformation are indicated. The derivation of Feynman's rules for quantum processes are calculated on the base of generalized normal product of operators. The way of reduction formula derivations is indicated and the suitable Green's functions are introduced. A generating functional for this Green's function is defined and the system of functional equations for them is obtained. The representation of different generating funcationals by means of functional integrals is introduced. Some consequences of S-matrix unitary condition are considered which leads to the generalization of the optic theorem
Presheaves of Superselection Structures in Curved Spacetimes
Vasselli, Ezio
2015-04-01
We show that superselection structures on curved spacetimes that are expected to describe quantum charges affected by the underlying geometry are categories of sections of presheaves of symmetric tensor categories. When an embedding functor is given, the superselection structure is a Tannaka-type dual of a locally constant group bundle, which hence becomes a natural candidate for the role of the gauge group. Indeed, we show that any locally constant group bundle (with suitable structure group) acts on a net of C* algebras fulfilling normal commutation relations on an arbitrary spacetime. We also give examples of gerbes of C* algebras, defined by Wightman fields and constructed using projective representations of the fundamental group of the spacetime, which we propose as solutions for the problem that existence and uniqueness of the embedding functor are not guaranteed.
Quantitative traits and diversification.
FitzJohn, Richard G
2010-12-01
Quantitative traits have long been hypothesized to affect speciation and extinction rates. For example, smaller body size or increased specialization may be associated with increased rates of diversification. Here, I present a phylogenetic likelihood-based method (quantitative state speciation and extinction [QuaSSE]) that can be used to test such hypotheses using extant character distributions. This approach assumes that diversification follows a birth-death process where speciation and extinction rates may vary with one or more traits that evolve under a diffusion model. Speciation and extinction rates may be arbitrary functions of the character state, allowing much flexibility in testing models of trait-dependent diversification. I test the approach using simulated phylogenies and show that a known relationship between speciation and a quantitative character could be recovered in up to 80% of the cases on large trees (500 species). Consistent with other approaches, detecting shifts in diversification due to differences in extinction rates was harder than when due to differences in speciation rates. Finally, I demonstrate the application of QuaSSE to investigate the correlation between body size and diversification in primates, concluding that clade-specific differences in diversification may be more important than size-dependent diversification in shaping the patterns of diversity within this group.
Endoscopic sleeve gastroplasty: the learning curve.
Hill, Christine; El Zein, Mohamad; Agnihotri, Abhishek; Dunlap, Margo; Chang, Angela; Agrawal, Alison; Barola, Sindhu; Ngamruengphong, Saowanee; Chen, Yen-I; Kalloo, Anthony N; Khashab, Mouen A; Kumbhari, Vivek
2017-09-01
Endoscopic sleeve gastroplasty (ESG) is gaining traction as a minimally invasive bariatric treatment. Concern that the learning curve may be slow, even among those proficient in endoscopic suturing, is a barrier to widespread implementation of the procedure. Therefore, we aimed to define the learning curve for ESG in a single endoscopist experienced in endoscopic suturing who participated in a 1-day ESG training program. Consecutive patients who underwent ESG between February 2016 and November 2016 were included. The performing endoscopist, who is proficient in endoscopic suturing for non-ESG procedures, participated in a 1-day ESG training session before offering ESG to patients. The outcome measurements were length of procedure (LOP) and number of plications per procedure. Nonlinear regression was used to determine the learning plateau and calculate the learning rate. Twenty-one consecutive patients (8 males), with mean age 47.7 ± 11.2 years and mean body mass index 41.8 ± 8.5 kg/m 2 underwent ESG. LOP decreased significantly across consecutive procedures, with a learning plateau at 101.5 minutes and a learning rate of 7 cases ( P = 0.04). The number of plications per procedure also decreased significantly across consecutive procedures, with a plateau at 8 sutures and a learning rate of 9 cases ( P < 0.001). Further, the average time per plication decreased significantly with consecutive procedures, reaching a plateau at 9 procedures ( P < 0.001). Endoscopists experienced in endoscopic suturing are expected to achieve a reduction in LOP and number of plications per procedure in successive cases, with progress plateauing at 7 and 9 cases, respectively.
Curved Radio Spectra of Weak Cluster Shocks
Kang, Hyesung; Ryu, Dongsu
2015-08-01
In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.
Theoretical foundations for environmental Kuznets curve analysis
Lantz, Van
This thesis provides a dynamic theory for analyzing the paths of aggregate output and pollution in a country over time. An infinite horizon, competitive growth-pollution model is explored in order to determine the role that economic scale, production techniques, and pollution regulations play in explaining the inverted U-shaped relationship between output and some forms of pollution (otherwise known as the Environmental Kuznets Curve, or EKC). Results indicate that the output-pollution relationship may follow a strictly increasing, strictly decreasing (but bounded), inverted U-shaped, or some combination of curves. While the 'scale' effect may cause output and pollution to exhibit a monotonic relationship, 'technique' and 'regulation' effects may ultimately cause a de-linking of these two variables. Pollution-minimizing energy regulation policies are also investigated within this framework. It is found that the EKC may be 'flattened' or even eliminated moving from a poorly-regulated economy to one that minimizes pollution. The model is calibrated to the US economy for output (gross national product, GNP) and two pollutants (sulfur dioxide, SO2, and carbon dioxide, CO2) over the period 1900 to 1990. Results indicate that the model replicates the observations quite well. The predominance of 'scale' effects cause aggregate SO2 and CO2 levels to increase with GNP in the early stages of development. Then, in the case of SO 2, 'technique' and 'regulation' effects may be the cause of falling SO2 levels with continued economic growth (establishing the EKC). CO2 continues to monotonically increase as output levels increase over time. The positive relationship may be due to the lack of regulations on this pollutant. If stricter regulation policies were instituted in the two case studies, an improved allocation of resources may result. While GNP may be 2.596 to 20% lower than what has been realized in the US economy (depending on the pollution variable analyzed), individual
Learning curves for solid oxide fuel cells
International Nuclear Information System (INIS)
Rivera-Tinoco, Rodrigo; Schoots, Koen; Zwaan, Bob van der
2012-01-01
Highlights: ► We present learning curves for fuel cells based on empirical data. ► We disentangle different cost reduction mechanisms for SOFCs. ► We distinguish between learning-by-doing, R and D, economies-of-scale and automation. - Abstract: In this article we present learning curves for solid oxide fuel cells (SOFCs). With data from fuel cell manufacturers we derive a detailed breakdown of their production costs. We develop a bottom-up model that allows for determining overall SOFC manufacturing costs with their respective cost components, among which material, energy, labor and capital charges. The results obtained from our model prove to deviate by at most 13% from total cost figures quoted in the literature. For the R and D stage of development and diffusion, we find local learning rates between 13% and 17% and we demonstrate that the corresponding cost reductions result essentially from learning-by-searching effects. When considering periods in time that focus on the pilot and early commercial production stages, we find regional learning rates of 27% and 1%, respectively, which we assume derive mainly from genuine learning phenomena. These figures turnout significantly higher, approximately 44% and 12% respectively, if also effects of economies-of-scale and automation are included. When combining all production stages we obtain lr = 35%, which represents a mix of cost reduction phenomena. This high learning rate value and the potential to scale up production suggest that continued efforts in the development of SOFC manufacturing processes, as well as deployment and use of SOFCs, may lead to substantial further cost reductions.
SUPERNOVA LIGHT CURVES POWERED BY FALLBACK ACCRETION
Energy Technology Data Exchange (ETDEWEB)
Dexter, Jason; Kasen, Daniel, E-mail: jdexter@berkeley.edu [Departments of Physics and Astronomy, University of California, Berkeley, CA 94720 (United States)
2013-07-20
Some fraction of the material ejected in a core collapse supernova explosion may remain bound to the compact remnant, and eventually turn around and fall back. We show that the late time ({approx}>days) power potentially associated with the accretion of this 'fallback' material could significantly affect the optical light curve, in some cases producing super-luminous or otherwise peculiar supernovae. We use spherically symmetric hydrodynamical models to estimate the accretion rate at late times for a range of progenitor masses and radii and explosion energies. The accretion rate onto the proto-neutron star or black hole decreases as M-dot {proportional_to}t{sup -5/3} at late times, but its normalization can be significantly enhanced at low explosion energies, in very massive stars, or if a strong reverse shock wave forms at the helium/hydrogen interface in the progenitor. If the resulting super-Eddington accretion drives an outflow which thermalizes in the outgoing ejecta, the supernova debris will be re-energized at a time when photons can diffuse out efficiently. The resulting light curves are different and more diverse than previous fallback supernova models which ignored the input of accretion power and produced short-lived, dim transients. The possible outcomes when fallback accretion power is significant include super-luminous ({approx}> 10{sup 44} erg s{sup -1}) Type II events of both short and long durations, as well as luminous Type I events from compact stars that may have experienced significant mass loss. Accretion power may unbind the remaining infalling material, causing a sudden decrease in the brightness of some long duration Type II events. This scenario may be relevant for explaining some of the recently discovered classes of peculiar and rare supernovae.
Speed choice and steering behavior in curve driving
Winsum, W. van; Godthelp, J.
1996-01-01
The relation between speed choice and steering performance during curve negotiation was studied in a driving simulator. The hypothesis was that curve radius and steering competence both affect steering error during curve driving, resulting in compensatory speed choice. In this, the control of safety
Learning curve tool applications in DOE materials management activities
International Nuclear Information System (INIS)
Lipinski, A.
1994-01-01
This paper will examine the application of learning curve theory, an economic theory that quantifies cost savings over time in a labor intensive process. Learning curve theory has been traditionally applied to a production process. This paper examines the application of learning curve theory in cost estimating of waste characterization in storage at a DOE facility
Spider diffraction: a comparison of curved and straight legs
International Nuclear Information System (INIS)
Richter, J.L.
1984-01-01
It has been known for some time that, if curved legs rather than the usual straight ones are used in the spider that supports the secondary optics in certain telescopes, the visible diffraction effect is reduced. Fraunhofer theory is used to calculate the diffraction effects due to the curved leg spider. Calculated and photographic diffraction patterns are compared for straight and curved leg spiders
Retiring the Short-Run Aggregate Supply Curve
Elwood, S. Kirk
2010-01-01
The author argues that the aggregate demand/aggregate supply (AD/AS) model is significantly improved--although certainly not perfected--by trimming it of the short-run aggregate supply (SRAS) curve. Problems with the SRAS curve are shown first for the AD/AS model that casts the AD curve as identifying the equilibrium level of output associated…
Schlösser, Tom P C; van Stralen, M; Chu, Winnie C W; Lam, Tsz-Ping; Ng, Bobby K W; Vincken, Koen L; Cheng, Jack C Y; Castelein, RM
2016-01-01
INTRODUCTION: Although much attention has been given to the global three-dimensional aspect of adolescent idiopathic scoliosis (AIS), the accurate three-dimensional morphology of the primary and compensatory curves, as well as the intervening junctional segments, in the scoliotic spine has not been
Section curve reconstruction and mean-camber curve extraction of a point-sampled blade surface.
Directory of Open Access Journals (Sweden)
Wen-long Li
Full Text Available The blade is one of the most critical parts of an aviation engine, and a small change in the blade geometry may significantly affect the dynamics performance of the aviation engine. Rapid advancements in 3D scanning techniques have enabled the inspection of the blade shape using a dense and accurate point cloud. This paper proposes a new method to achieving two common tasks in blade inspection: section curve reconstruction and mean-camber curve extraction with the representation of a point cloud. The mathematical morphology is expanded and applied to restrain the effect of the measuring defects and generate an ordered sequence of 2D measured points in the section plane. Then, the energy and distance are minimized to iteratively smoothen the measured points, approximate the section curve and extract the mean-camber curve. In addition, a turbine blade is machined and scanned to observe the curvature variation, energy variation and approximation error, which demonstrates the availability of the proposed method. The proposed method is simple to implement and can be applied in aviation casting-blade finish inspection, large forging-blade allowance inspection and visual-guided robot grinding localization.
Induction of Micronuclei in Human Fibroblasts across the Bragg Curve of Energetic Si and Fe Ions
Wu, H.; Rusek, A.; Hada, M.
2006-01-01
The space environment consists of a varying field of radiation particles including high-energy ions, with spacecraft shielding material providing the major protection to astronauts from harmful exposure. Unlike low-LET gamma or X-rays, the presence of shielding does not always reduce the radiation risks for energetic charged particle exposure. Since the dose delivered by the charged particle increases sharply as the particle approaches the end of its range, a position known as the Bragg peak, the Bragg curve does not necessarily represent the biological damage along the particle traversal since biological effects are influenced by the track structure of both primary and secondary particles. Therefore, the biological Bragg curve is dependent on the energy and the type of the primary particle, and may vary for different biological endpoints. We studied micronuclei (MN) induction across the Bragg curve of Si and Fe ions at incident energies of 300 MeV/nucleon and 1 GeV/nucleon. A quantitative biological response curve did not reveal an increased yield of MN at the location of the Bragg peak. However, the ratio of mono- to bi-nucleated cells, which indicates inhibition in cell progression, increased at the Bragg peak location. These results confirm the hypothesis that severely damaged cells at the Bragg peak are likely to go through reproduction death.
Sabot Front Borerider Stiffness vs. Dispersion: Finding the Knee in the Curve
Directory of Open Access Journals (Sweden)
Alan F. Hathaway
2001-01-01
Full Text Available In the design of armor piercing, fin-stabilized, discarding sabot projectiles, the radial stiffness of the sabot front borerider has a significant impact on the projectile's dispersion and is, therefore, an important design consideration. Whether designing a new projectile or trying to improve an existing design, projectile designers can achieve front borerider stiffness without understanding its affect on dispersion characteristics. There is a knee in the stiffness vs. dispersion curve at which a change in the sabot front borerider stiffness will have a significant impact on dispersion or no impact at all depending on whether the stiffness is increased or decreased. The subject of this paper is an analytical approach to quantitatively determine the knee in the curve. Results from using this approach on the M865 APFSDS projectile are also presented.
Weinberger, Michelle; Sonneveldt, Emily; Stover, John
2017-12-22
Most frameworks for family planning include both access and demand interventions. Understanding how these two are linked and when each should be prioritized is difficult. The maximum contraceptive prevalence 'demand curve' was created based on a relationship between the modern contraceptive prevalence rate (mCPR) and mean ideal number of children to allow for a quantitative assessment of the balance between access and demand interventions. The curve represents the maximum mCPR that is likely to be seen given fertility intentions and related norms and constructs that influence contraceptive use. The gap between a country's mCPR and this maximum is referred to as the 'potential use gap.' This concept can be used by countries to prioritize access investments where the gap is large, and discuss implications for future contraceptive use where the gap is small. It is also used within the FP Goals model to ensure mCPR growth from access interventions does not exceed available demand.
Comparison of wind turbines based on power curve analysis
Energy Technology Data Exchange (ETDEWEB)
NONE
1998-02-01
In the study measured power curves for 46 wind turbines were analyzed with the purpose to establish the basis for a consistent comparison of the efficiency of the wind turbines. Emphasis is on wind turbines above 500 kW rated power, with power curves measured after 1994 according to international recommendations. The available power curves fulfilling these requirements were smoothened according to a procedure developed for the purpose in such a way that the smoothened power curves are equally representative as the measured curves. The resulting smoothened power curves are presented in a standardized format for the subsequent processing. Using wind turbine data from the power curve documentation the analysis results in curves for specific energy production (kWh/M{sup 2}/yr) versus specific rotor load (kW/M{sup 2}) for a range of mean wind speeds. On this basis generalized curves for specific annual energy production versus specific rotor load are established for a number of generalized wind turbine concepts. The 46 smoothened standardized power curves presented in the report, the procedure developed to establish them, and the results of the analysis based on them aim at providers of measured power curves as well as users of them including manufacturers, advisors and decision makers. (au)
Multiparametric Quantitative Ultrasound Imaging in Assessment of Chronic Kidney Disease.
Gao, Jing; Perlman, Alan; Kalache, Safa; Berman, Nathaniel; Seshan, Surya; Salvatore, Steven; Smith, Lindsey; Wehrli, Natasha; Waldron, Levi; Kodali, Hanish; Chevalier, James
2017-11-01
To evaluate the value of multiparametric quantitative ultrasound imaging in assessing chronic kidney disease (CKD) using kidney biopsy pathologic findings as reference standards. We prospectively measured multiparametric quantitative ultrasound markers with grayscale, spectral Doppler, and acoustic radiation force impulse imaging in 25 patients with CKD before kidney biopsy and 10 healthy volunteers. Based on all pathologic (glomerulosclerosis, interstitial fibrosis/tubular atrophy, arteriosclerosis, and edema) scores, the patients with CKD were classified into mild (no grade 3 and quantitative ultrasound parameters included kidney length, cortical thickness, pixel intensity, parenchymal shear wave velocity, intrarenal artery peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index. We tested the difference in quantitative ultrasound parameters among mild CKD, moderate to severe CKD, and healthy controls using analysis of variance, analyzed correlations of quantitative ultrasound parameters with pathologic scores and the estimated glomerular filtration rate (GFR) using Pearson correlation coefficients, and examined the diagnostic performance of quantitative ultrasound parameters in determining moderate CKD and an estimated GFR of less than 60 mL/min/1.73 m 2 using receiver operating characteristic curve analysis. There were significant differences in cortical thickness, pixel intensity, PSV, and EDV among the 3 groups (all P quantitative ultrasound parameters, the top areas under the receiver operating characteristic curves for PSV and EDV were 0.88 and 0.97, respectively, for determining pathologic moderate to severe CKD, and 0.76 and 0.86 for estimated GFR of less than 60 mL/min/1.73 m 2 . Moderate to good correlations were found for PSV, EDV, and pixel intensity with pathologic scores and estimated GFR. The PSV, EDV, and pixel intensity are valuable in determining moderate to severe CKD. The value of shear wave velocity in
Compact Hilbert Curve Index Algorithm Based on Gray Code
Directory of Open Access Journals (Sweden)
CAO Xuefeng
2016-12-01
Full Text Available Hilbert curve has best clustering in various kinds of space filling curves, and has been used as an important tools in discrete global grid spatial index design field. But there are lots of redundancies in the standard Hilbert curve index when the data set has large differences between dimensions. In this paper, the construction features of Hilbert curve is analyzed based on Gray code, and then the compact Hilbert curve index algorithm is put forward, in which the redundancy problem has been avoided while Hilbert curve clustering preserved. Finally, experiment results shows that the compact Hilbert curve index outperforms the standard Hilbert index, their 1 computational complexity is nearly equivalent, but the real data set test shows the coding time and storage space decrease 40%, the speedup ratio of sorting speed is nearly 4.3.
The Environmental Kuznets Curve. An empirical analysis for OECD countries
Energy Technology Data Exchange (ETDEWEB)
Georgiev, E.
2008-09-15
This paper tests the Environmental Kuznets Curve hypothesis for four local (SOx, NOx, CO, VOC) and two global (CO2, GHG) air pollutants. Using a new panel data set of thirty OECD countries, the paper finds that the postulated inverted U-shaped relationship between income and pollution does not hold for all gases. A meaningful Environmental Kuznets Curve exists only for CO, VOC and NOx, where for CO2 the curve is monotonically increasing. For GHG there is indication of an inverted U-shaped relationship between income and pollution, but still most countries are on the increasing path of the curve and hence the future development of the curve is uncertain. For SOx it was found that emissions follow an U-shaped curve. Based on the empirical results, the paper concludes that the Environmental Kuznets Curve does not hold for all gases, it is rather an empirical artefact than a regularity.
The Environmental Kuznets Curve. An empirical analysis for OECD countries
International Nuclear Information System (INIS)
Georgiev, E.
2008-09-01
This paper tests the Environmental Kuznets Curve hypothesis for four local (SOx, NOx, CO, VOC) and two global (CO2, GHG) air pollutants. Using a new panel data set of thirty OECD countries, the paper finds that the postulated inverted U-shaped relationship between income and pollution does not hold for all gases. A meaningful Environmental Kuznets Curve exists only for CO, VOC and NOx, where for CO2 the curve is monotonically increasing. For GHG there is indication of an inverted U-shaped relationship between income and pollution, but still most countries are on the increasing path of the curve and hence the future development of the curve is uncertain. For SOx it was found that emissions follow an U-shaped curve. Based on the empirical results, the paper concludes that the Environmental Kuznets Curve does not hold for all gases, it is rather an empirical artefact than a regularity.
International Nuclear Information System (INIS)
Gries, W.H.
1976-06-01
This is a report of the study of the implantation of heavy ions at medium keV-energies into electrically conducting mono-elemental solids, at ion doses too small to cause significant loss of the implanted ions by resputtering. The study has been undertaken to investigate the possibility of accurate portioning of matter in submicrogram quantities, with some specific applications in mind. The problem is extensively investigated both on a theoretical level and in practice. A mathematical model is developed for calculating the loss of implanted ions by resputtering as a function of the implanted ion dose and the sputtering yield. Numerical data are produced therefrom which permit a good order-of-magnitude estimate of the loss for any ion/solid combination in which the ions are heavier than the solid atoms, and for any ion energy from 10 to 300 keV. The implanted ion dose is measured by integration of the ion beam current, and equipment and techniques are described which make possible the accurate integration of an ion current in an electromagnetic isotope separator. The methods are applied to two sample cases, one being a stable isotope, the other a radioisotope. In both cases independent methods are used to show that the implantation is indeed quantitative, as predicted. At the same time the sample cases are used to demonstrate two possible applications for quantitative ion implantation, viz. firstly for the manufacture of calibration standards for instrumental micromethods of elemental trace analysis in metals, and secondly for the determination of the half-lives of long-lived radioisotopes by a specific activity method. It is concluded that the present study has advanced quantitative ion implantation to the state where it can be successfully applied to the solution of problems in other fields
Water Retention Curves of Opalinus Clay
Energy Technology Data Exchange (ETDEWEB)
Villar, M. V.; Romero, F. J.
2012-11-01
The water retention curve of Opalinus clay samples was determined under different conditions: total and matric suction, stress or no-stress conditions, wetting and drying paths. Through the fitting of these results to the van Genuchten expression the P parameter, related to the air entry value (AEV), was obtained. The AEV is the suction value above which air is able to enter the pores of the sample, and consequently, above which 2-phase flow can take place in the soil pore structure. The samples used in this research came from two different boreholes, BHT-1 and BHG-D1, but the behaviour of them did not depend on their location, what was probably due to the fact that both were drilled in the shay facies of the Opalinus clay. There was not a distinct difference between the results obtained under total or matric suctions. In the drying paths, both the water contents and the degrees of saturation tended to be higher when total suction was applied, however the reverse trend was observed for the water contents reached in wetting paths. As well, no clear difference was observed in the water retention curves obtained in odometers under matric and total suctions, what points to the osmotic component of suction in Opalinus clay not being significant. Overall, the water contents were lower and the degrees of saturation higher when suction was applied under vertical stress, what would indicate that the water retention capacity was lower under 8 MPa vertical stress than under free volume conditions. This vertical stress value is slightly higher than the maximum in situ stress. Also, the samples showed hysteresis according to the expected behaviour, i.e. the water contents for a given suction were higher during a drying path than during a wetting path. The P values obtained were between 6 and 34 MPa, and tended to be higher for the samples tested under stress, in drying paths and when total suction was used. The air entry value calculated from the mercury intrusion porosimetry
Energy Technology Data Exchange (ETDEWEB)
McGreevy, John Austen; /Stanford U., Phys. Dept.
2005-07-06
This thesis is a study of D-branes in string compactifications. In this context, D-branes are relevant as an important component of the nonperturbative spectrum, as an incisive probe of these backgrounds, and as a natural stringy tool for localizing gauge interactions. In the first part of the thesis, we discuss half-BPS D-branes in compactifications of type II string theory on Calabi-Yau threefolds. The results we describe for these objects are pertinent both in their role as stringy brane-worlds, and in their role as solitonic objects. In particular, we determine couplings of these branes to the moduli determining the closed-string geometry, both perturbatively and non-perturbatively in the worldsheet expansion. We provide a local model for transitions in moduli space where the BPS spectrum jumps, and discuss the extension of mirror symmetry between Calabi-Yau manifolds to the case when D-branes are present. The next section is an interlude which provides some applications of D-branes to other curved backgrounds of string theory. In particular, we discuss a surprising phenomenon in which fundamental strings moving through background Ramond-Ramond fields dissolve into large spherical D3-branes. This mechanism is used to explain a previously-mysterious fact discovered via the AdS-CFT correspondence. Next, we make a connection between type IIA string vacua of the type discussed in the first section and M-theory compactifications on manifolds of G{sub 2} holonomy. Finally we discuss constructions of string vacua which do not have large radius limits. In the final part of the thesis, we develop techniques for studying the worldsheets of open strings ending on the curved D-branes studied in the first section. More precisely, we formulate a large class of massive two-dimensional gauge theories coupled to boundary matter, which flow in the infrared to the relevant boundary conformal field theories. Along with many other applications, these techniques are used to describe
Water Retention Curves of Opalinus Clay
International Nuclear Information System (INIS)
Villar, M. V.; Romero, F. J.
2012-01-01
The water retention curve of Opalinus clay samples was determined under different conditions: total and matric suction, stress or no-stress conditions, wetting and drying paths. Through the fitting of these results to the van Genuchten expression the P parameter, related to the air entry value (AEV), was obtained. The AEV is the suction value above which air is able to enter the pores of the sample, and consequently, above which 2-phase flow can take place in the soil pore structure. The samples used in this research came from two different boreholes, BHT-1 and BHG-D1, but the behaviour of them did not depend on their location, what was probably due to the fact that both were drilled in the shay facies of the Opalinus clay. There was not a distinct difference between the results obtained under total or matric suctions. In the drying paths, both the water contents and the degrees of saturation tended to be higher when total suction was applied, however the reverse trend was observed for the water contents reached in wetting paths. As well, no clear difference was observed in the water retention curves obtained in odometers under matric and total suctions, what points to the osmotic component of suction in Opalinus clay not being significant. Overall, the water contents were lower and the degrees of saturation higher when suction was applied under vertical stress, what would indicate that the water retention capacity was lower under 8 MPa vertical stress than under free volume conditions. This vertical stress value is slightly higher than the maximum in situ stress. Also, the samples showed hysteresis according to the expected behaviour, i.e. the water contents for a given suction were higher during a drying path than during a wetting path. The P values obtained were between 6 and 34 MPa, and tended to be higher for the samples tested under stress, in drying paths and when total suction was used. The air entry value calculated from the mercury intrusion porosimetry
Quantitative cardiac computed tomography
Energy Technology Data Exchange (ETDEWEB)
Thelen, M.; Dueber, C.; Wolff, P.; Erbel, R.; Hoffmann, T.
1985-06-01
The scope and limitations of quantitative cardiac CT have been evaluated in a series of experimental and clinical studies. The left ventricular muscle mass was estimated by computed tomography in 19 dogs (using volumetric methods, measurements in two axes and planes and reference volume). There was good correlation with anatomical findings. The enddiastolic volume of the left ventricle was estimated in 22 patients with cardiomyopathies; using angiography as a reference, CT led to systematic under-estimation. It is also shown that ECG-triggered magnetic resonance tomography results in improved visualisation and may be expected to improve measurements of cardiac morphology.
Development of a precipitation-area curve for warning criteria of short-duration flash flood
Bae, Deg-Hyo; Lee, Moon-Hwan; Moon, Sung-Keun
2018-01-01
This paper presents quantitative criteria for flash flood warning that can be used to rapidly assess flash flood occurrence based on only rainfall estimates. This study was conducted for 200 small mountainous sub-catchments of the Han River basin in South Korea because South Korea has recently suffered many flash flood events. The quantitative criteria are calculated based on flash flood guidance (FFG), which is defined as the depth of rainfall of a given duration required to cause frequent flooding (1-2-year return period) at the outlet of a small stream basin and is estimated using threshold runoff (TR) and antecedent soil moisture conditions in all sub-basins. The soil moisture conditions were estimated during the flooding season, i.e., July, August and September, over 7 years (2002-2009) using the Sejong University Rainfall Runoff (SURR) model. A ROC (receiver operating characteristic) analysis was used to obtain optimum rainfall values and a generalized precipitation-area (P-A) curve was developed for flash flood warning thresholds. The threshold function was derived as a P-A curve because the precipitation threshold with a short duration is more closely related to basin area than any other variables. For a brief description of the P-A curve, generalized thresholds for flash flood warnings can be suggested for rainfall rates of 42, 32 and 20 mm h-1 in sub-basins with areas of 22-40, 40-100 and > 100 km2, respectively. The proposed P-A curve was validated based on observed flash flood events in different sub-basins. Flash flood occurrences were captured for 9 out of 12 events. This result can be used instead of FFG to identify brief flash flood (less than 1 h), and it can provide warning information to decision-makers or citizens that is relatively simple, clear and immediate.
Rational points, rational curves, and entire holomorphic curves on projective varieties
Gasbarri, Carlo; Roth, Mike; Tschinkel, Yuri
2015-01-01
This volume contains papers from the Short Thematic Program on Rational Points, Rational Curves, and Entire Holomorphic Curves and Algebraic Varieties, held from June 3-28, 2013, at the Centre de Recherches Mathématiques, Université de Montréal, Québec, Canada. The program was dedicated to the study of subtle interconnections between geometric and arithmetic properties of higher-dimensional algebraic varieties. The main areas of the program were, among others, proving density of rational points in Zariski or analytic topology on special varieties, understanding global geometric properties of rationally connected varieties, as well as connections between geometry and algebraic dynamics exploring new geometric techniques in Diophantine approximation.
Learning curves for solid oxide fuel cells
Energy Technology Data Exchange (ETDEWEB)
Rivera-Tinoco, R.; Schoots, K. [Energy research Centre of the Netherlands (Netherlands). Policy Studies; Zwaan, B.C.C. van der [Energy research Centre of the Netherlands (Netherlands). Policy Studies; Columbia Univ., New York City, NY (United States). Lenfest Center for Sustainable Energy
2010-07-01
We present learning curves for solid oxide fuel cells (SOFCs) and combined heat and power (CHP) SOFC systems with an electric capacity between 1 and 250 kW. On the basis of the cost breakdown of production cost data from fuel cell manufacturers, we developed a bottom-up model that allows for determining overall manufacturing costs from their respective cost components, among which material, energy, labor, and capital charges. The results obtained from our model prove to deviate by at most 13% from total cost figures quoted in the literature. For the early pilot stage of development, we find for SOFC manufacturing a learning rate between 14% and 17%, and for total SOFC system fabrication between 16% and 19%. We argue that the corresponding cost reductions result largely from learning-by-searching effects (R and D) rather than learning-by-doing. When considering a longer time frame that includes the early commercial production stage, we find learning rates between 14% and 39%, which represent a mix of phenomena such as learning-by-doing, learning-by-searching, economies-of-scale and automation. (orig.)