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…
Directory of Open Access Journals (Sweden)
Fabyano Fonseca e Silva
Full Text Available ABSTRACT: Genome association analyses have been successful in identifying quantitative trait loci (QTLs for pig body weights measured at a single age. However, when considering the whole weight trajectories over time in the context of genome association analyses, it is important to look at the markers that affect growth curve parameters. The easiest way to consider them is via the two-step method, in which the growth curve parameters and marker effects are estimated separately, thereby resulting in a reduction of the statistical power and the precision of estimates. One efficient solution is to adopt nonlinear mixed models (NMM, which enables a joint modeling of the individual growth curves and marker effects. Our aim was to propose a genome association analysis for growth curves in pigs based on NMM as well as to compare it with the traditional two-step method. In addition, we also aimed to identify the nearest candidate genes related to significant SNP (single nucleotide polymorphism markers. The NMM presented a higher number of significant SNPs for adult weight (A and maturity rate (K, and provided a direct way to test SNP significance simultaneously for both the A and K parameters. Furthermore, all significant SNPs from the two-step method were also reported in the NMM analysis. The ontology of the three candidate genes (SH3BGRL2, MAPK14, and MYL9 derived from significant SNPs (simultaneously affecting A and K allows us to make inferences with regards to their contribution to the pig growth process in the population studied.
De Mello, Fernanda; Oliveira, Carlos A L; Ribeiro, Ricardo P; Resende, Emiko K; Povh, Jayme A; Fornari, Darci C; Barreto, Rogério V; McManus, Concepta; Streit, Danilo
2015-01-01
Was evaluated the pattern of growth among females and males of tambaqui by Gompertz nonlinear regression model. Five traits of economic importance were measured on 145 animals during the three years, totaling 981 morphometric data analyzed. Different curves were adjusted between males and females for body weight, height and head length and only one curve was adjusted to the width and body length. The asymptotic weight (a) and relative growth rate to maturity (k) were different between sexes in animals with ± 5 kg; slaughter weight practiced by a specific niche market, very profitable. However, there was no difference between males and females up to ± 2 kg; slaughter weight established to supply the bigger consumer market. Females showed weight greater than males (± 280 g), which are more suitable for fish farming purposes defined for the niche market to larger animals. In general, males had lower maximum growth rate (8.66 g / day) than females (9.34 g / day), however, reached faster than females, 476 and 486 days growth rate, respectively. The height and length body are the traits that contributed most to the weight at 516 days (P <0.001).
Multiphasic growth curve analysis.
Koops, W.J.
1986-01-01
Application of a multiphasic growth curve is demonstrated with 4 data sets, adopted from literature. The growth curve used is a summation of n logistic growth functions. Human height growth curves of this type are known as "double logistic" (n = 2) and "triple logistic" (n = 3) growth curves (Bock
Space curves, anholonomy and nonlinearity
Indian Academy of Sciences (India)
Radha Balakrishnan
2005-04-01
Using classical differential geometry, we discuss the phenomenon of anholonomy that gets associated with a static and a moving curve. We obtain the expressions for the respective geometric phases in the two cases and interpret them. We show that there is a close connection between anholonomy and nonlinearity in a wide class of nonlinear systems.
Kumar, P. Ramesh; Gunaseelan, R.; Raj, A. Antony; Selvakumar, S.; Sagayaraj, P.
2012-06-01
Nonlinear optical amino-acid single crystal of L-phenylalanine hydrochloride (LPHCl) was successfully grown by unidirectional Sankaranarayanan-Ramasamy (SR) method under ambient conditions for the first time. The grown single crystal was subjected to different characterization analyses in order to find out its suitability for device fabrication. The crystalline perfection was evaluated using high-resolution X-ray diffractometry. It is evident from the optical absorption study that crystal has excellent transmission in the entire visible region with its lower cut off wavelength around 290 nm.
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...
Geometrodynamics: The Nonlinear Dynamics of Curved Spacetime
Scheel, Mark A.; Thorne, Kip S.
2017-01-01
We review discoveries in the nonlinear dynamics of curved spacetime, largely made possible by numerical solutions of Einstein's equations. We discuss critical phenomena and self-similarity in gravitational collapse, the behavior of spacetime curvature near singularities, the instability of black strings in 5 spacetime dimensions, and the collision of four-dimensional black holes. We also discuss the prospects for further discoveries in geometrodynamics via observation of gravitational waves.
Identification of systems containing nonlinear stiffnesses using backbone curves
Londoño, Julián M.; Cooper, Jonathan E.; Neild, Simon A.
2017-02-01
This paper presents a method for the dynamic identification of structures containing discrete nonlinear stiffnesses. The approach requires the structure to be excited at a single resonant frequency, enabling measurements to be made in regimes of large displacements where nonlinearities are more likely to be significant. Measured resonant decay data is used to estimate the system backbone curves. Linear natural frequencies and nonlinear parameters are identified using these backbone curves assuming a form for the nonlinear behaviour. Numerical and experimental examples, inspired by an aerospace industry test case study, are considered to illustrate how the method can be applied. Results from these models demonstrate that the method can successfully deliver nonlinear models able to predict the response of the test structure nonlinear dynamics.
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....
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.
Nonlinear Gompertz Curve Models of Achievement Gaps in Mathematics and Reading
Cameron, Claire E.; Grimm, Kevin J.; Steele, Joel S.; Castro-Schilo, Laura; Grissmer, David W.
2015-01-01
This study examined achievement trajectories in mathematics and reading from school entry through the end of middle school with linear and nonlinear growth curves in 2 large longitudinal data sets (National Longitudinal Study of Youth--Children and Young Adults and Early Childhood Longitudinal Study--Kindergarten Cohort [ECLS-K]). The S-shaped…
The Gompertzian curve reveals fractal properties of tumor growth
Energy Technology Data Exchange (ETDEWEB)
Waliszewski, Przemyslaw; Konarski, Jerzy
2003-06-01
The normalized Gompertzian curve reflecting growth of experimental malignant tumors in time can be fitted by the power function y(t)=at{sup b} with the coefficient of nonlinear regression r{>=}0.95, in which the exponent b is a temporal fractal dimension, (i.e., a real number), and time t is a scalar. This curve is a fractal, (i.e., fractal dimension b exists, it changes along the time scale, the Gompertzian function is a contractable mapping of the Banach space R of the real numbers, holds the Banach theorem about the fix point, and its derivative is {<=}1). This denotes that not only space occupied by the interacting cancer cells, but also local, intrasystemic time, in which tumor growth occurs, possesses fractal structure. The value of the mean temporal fractal dimension decreases along the curve approaching eventually integer values; a fact consistent with our hypothesis that the fractal structure is lost during tumor progression.
Non-linear Behavior of Curved Sandwich Panels
DEFF Research Database (Denmark)
Berggreen, Carl Christian; Jolma, P.; Karjalainen, J. P.;
2003-01-01
In this paper the non-linear behavior of curved sandwich panels is investigated both numerically and experimentally. Focus is on various aspects of finite element modeling and calculation procedures. A simply supported, singly curved, CFRP/PVC sandwich panel is analyzed under uniform pressure load...... and results are compared to test data. A novel test arrangement utilizing a water filled cushion to create the uniform pressure load on curved panel specimen is used to obtain the experimental data. The panel is modeled with three different commercial finite element codes. Two implicit and one explicit code...... are used with various element types, modeling approaches and material models. The results show that the theoretical and experimental methods generally show fair agreement in panel non-linear behavior before collapse. It is also shown that special attention to detail has to be taken, because the predicted...
Growth Curves for Girls with Turner Syndrome
Bertapelli, Fabio; Barros-Filho, Antonio de Azevedo; Antonio, Maria Ângela Reis de Góes Monteiro; Barbeta, Camila Justino de Oliveira; de Lemos-Marini, Sofia Helena Valente
2014-01-01
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. PMID:24949463
Growth Curves for Girls with Turner Syndrome
Directory of Open Access Journals (Sweden)
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.
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.
Classical black holes: the nonlinear dynamics of curved spacetime.
Thorne, Kip S
2012-08-03
Numerical simulations have revealed two types of physical structures, made from curved spacetime, that are attached to black holes: tendexes, which stretch or squeeze anything they encounter, and vortexes, which twist adjacent inertial frames relative to each other. When black holes collide, their tendexes and vortexes interact and oscillate (a form of nonlinear dynamics of curved spacetime). These oscillations generate gravitational waves, which can give kicks up to 4000 kilometers per second to the merged black hole. The gravitational waves encode details of the spacetime dynamics and will soon be observed and studied by the Laser Interferometer Gravitational Wave Observatory and its international partners.
Genomic growth curves of an outbred pig population
Directory of Open Access Journals (Sweden)
Fabyano Fonseca e Silva
2013-01-01
Full Text Available In the current post-genomic era, the genetic basis of pig growth can be understood by assessing SNP marker effects and genomic breeding values (GEBV based on estimates of these growth curve parameters as phenotypes. Although various statistical methods, such as random regression (RR-BLUP and Bayesian LASSO (BL, have been applied to genomic selection (GS, none of these has yet been used in a growth curve approach. In this work, we compared the accuracies of RR-BLUP and BL using empirical weight-age data from an outbred F2 (Brazilian Piau X commercial population. The phenotypes were determined by parameter estimates using a nonlinear logistic regression model and the halothane gene was considered as a marker for evaluating the assumptions of the GS methods in relation to the genetic variation explained by each locus. BL yielded more accurate values for all of the phenotypes evaluated and was used to estimate SNP effects and GEBV vectors. The latter allowed the construction of genomic growth curves, which showed substantial genetic discrimination among animals in the final growth phase. The SNP effect estimates allowed identification of the most relevant markers for each phenotype, the positions of which were coincident with reported QTL regions for growth traits.
ANALYTIC INVARIANT CURVES OF A NONLINEAR SECOND ORDER DIFFERENCE EQUATION
Institute of Scientific and Technical Information of China (English)
Wang Wusheng
2009-01-01
This article studies the existence of analytic invariant curves for a nonlinear second order difference equation which was modeled from macroeconomics of the business cycle. The author not only discusses the case of the eigenvalue off the unit circle S1 and the case on S1 with the Diophantine condition but also considers the case of the eigenvalue at a root of the unity, which obviously violates the Diophantine condition.
Directory of Open Access Journals (Sweden)
Kleber Régis Santoro
2005-12-01
Full Text Available Objetivou-se estimar parâmetros genéticos e fenotípicos de curvas de crescimento de modelos não-lineares. Foram analisados dados de pesagem constantes no banco de dados de Controle de Desenvolvimento Ponderal da Associação Brasileira de Criadores de Zebu (ABCZ, referentes a 24.028 animais Zebu, nascidos entre 1960 e 2000, das raças Guzerá, Nelore e Nelore Mocho. As pesagens ocorreram ao nascimento e em intervalos de 90 dias até dois anos de idade. Os seguintes modelos não-lineares foram utilizados na análise dos dados de peso-idade: Brody, Gompertz, Logístico, von Bertalanffy e Richards. Os efeitos fixos estudados no modelo misto foram sexo, rebanho, ano e mês de nascimento e regime de criação. As herdabilidades para os parâmetros foram de baixa a alta magnitude, em geral, para todos os modelos. As correlações genéticas entre peso assintótico e taxa de maturidade e entre peso assintótico e velocidade de crescimento foram negativas, enquanto aquelas entre taxa de maturidade e velocidade de crescimento foram positivas. As correlações fenotípicas foram negativas entre peso assintótico e taxa de crescimento e entre peso assintótico e velocidade de crescimento e positivas entre taxa e velocidade de crescimento. Encontrou-se variabilidade possível de ser explorada em um programa de melhoramento genético, especialmente para a raça Nelore, que apresentou amostra de dados e resultados mais consistentes.Weight records of 24.028 zebu animals from Guzerá, Nelore, and Polled Nelore breeds available from Brazilian Association of Zebu Breeders (ABCZ database were used to estimate heritabilities of growth curve parameters. Non-linear Brody, Gompertz, Logistic, Mitscherlich, von Bertalanffy, Richards, and Double Logistic models including sex, farm, year of birth, month of birth, raising system, and interaction sex*raising system as fixed effects and sire and dam, as random effects were adjusted using weight-age records of animals
Non-linear Growth Models in Mplus and SAS.
Grimm, Kevin J; Ram, Nilam
2009-10-01
Non-linear growth curves or growth curves that follow a specified non-linear function in time enable researchers to model complex developmental patterns with parameters that are easily interpretable. In this paper we describe how a variety of sigmoid curves can be fit using the Mplus structural modeling program and the non-linear mixed-effects modeling procedure NLMIXED in SAS. Using longitudinal achievement data collected as part of a study examining the effects of preschool instruction on academic gain we illustrate the procedures for fitting growth models of logistic, Gompertz, and Richards functions. Brief notes regarding the practical benefits, limitations, and choices faced in the fitting and estimation of such models are included.
Bayesian modeling growth curves for quail assuming skewness in errors
Directory of Open Access Journals (Sweden)
Robson Marcelo Rossi
2014-06-01
Full Text Available Bayesian modeling growth curves for quail assuming skewness in errors - To assume normal distributions in the data analysis is common in different areas of the knowledge. However we can make use of the other distributions that are capable to model the skewness parameter in the situations that is needed to model data with tails heavier than the normal. This article intend to present alternatives to the assumption of the normality in the errors, adding asymmetric distributions. A Bayesian approach is proposed to fit nonlinear models when the errors are not normal, thus, the distributions t, skew-normal and skew-t are adopted. The methodology is intended to apply to different growth curves to the quail body weights. It was found that the Gompertz model assuming skew-normal errors and skew-t errors, respectively for male and female, were the best fitted to the data.
Nonlinear vibrations of functionally graded doubly curved shallow shells
Alijani, F.; Amabili, M.; Karagiozis, K.; Bakhtiari-Nejad, F.
2011-03-01
Nonlinear forced vibrations of FGM doubly curved shallow shells with a rectangular base are investigated. Donnell's nonlinear shallow-shell theory is used and the shell is assumed to be simply supported with movable edges. The equations of motion are reduced using the Galerkin method to a system of infinite nonlinear ordinary differential equations with quadratic and cubic nonlinearities. Using the multiple scales method, primary and subharmonic resonance responses of FGM shells are fully discussed and the effect of volume fraction exponent on the internal resonance conditions, softening/hardening behavior and bifurcations of the shallow shell when the excitation frequency is (i) near the fundamental frequency and (ii) near two times the fundamental frequency is shown. Moreover, using a code based on arclength continuation method, a bifurcation analysis is carried out for a special case with two-to-one internal resonance between the first and second doubly symmetric modes with respect to the panel's center ( ω13≈2 ω11). Bifurcation diagrams and Poincaré maps are obtained through direct time integration of the equations of motion and chaotic regions are shown by calculating Lyapunov exponents and Lyapunov dimension.
Nonlinear analysis of doubly curved shells: An analytical approach
Indian Academy of Sciences (India)
Y Nath; K Sandeep
2000-08-01
Dynamic analogues of vin Karman-Donnell type shell equations for doubly curved, thin isotropic shells in rectangular planform are formulated and expressed in displacement components. These nonlinear partial differential equations of motion are linearized by using a quadratic extrapolation technique. The spatial and temporal discretization of differential equatoins have been carried out by finite-degree Chebyshev polynomials and implicit Houbolt time-marching techniques respectively. Multiple regression besed on the least square error norm is employed to eliminate the incompatability generated due to spatial discretization (equations > unknowns). Spatial convergence study revealed that nine term expansion of each displacement in and respectively, is sufficient to yield fairly accurate results. Clamped and simply supported immovable doubly curved shallow shells are analysed. Results have been compared with those obtained by other numerical methods. Considering uniformly distributed normal loading, the results of static and dynamic analyses are presented.
Nonlinear Time Series Analysis of White Dwarf Light Curves
Jevtic, N.; Zelechoski, S.; Feldman, H.; Peterson, C.; Schweitzer, J.
2001-12-01
We use nonlinear time series analysis methods to examine the light intensity curves of white dwarf PG1351+489 obtained by the Whole Earth Telescope (WET). Though these methods were originally introduced to study chaotic systems, when a clear signature of determinism is found for the process generating an observable and it couples the active degrees of freedom of the system, then the notion of phase space provides a framework for exploring the system dynamics of nonlinear systems in general. With a pronounced single frequency, its harmonics and other frequencies of lower amplitude on a broadband background, the PG1351 light curve lends itself to the use of time delay coordinates. Our phase space reconstruction yields a triangular, toroidal three-dimensional shape. This differs from earlier results of a circular toroidal representation. We find a morphological similarity to a magnetic dynamo model developed for fast rotators that yields a union of both results: the circular phase space structure for the ascending portion of the cycle, and the triangular structure for the declining portion. The rise and fall of the dynamo cycle yield both different phase space representations and different correlation dimensions. Since PG1351 is known to have no significant fields, these results may stimulate the observation of light curves of known magnetic white dwarfs for comparison. Using other data obtained by the WET, we compare the phase space reconstruction of DB white dwarf PG1351 with that of GD 358 which has a more complex power spectrum. We also compare these results with those for PG1159. There is some general similarity between the results of the phase space reconstruction for the DB white dwarfs. As expected, the difference between the results for the DB white dwarfs and PG1159 is great.
Analysis of growth curve in Santa Ines females sheep
Directory of Open Access Journals (Sweden)
Elisa Junqueira Oliveira
2013-12-01
Full Text Available In a sheep production system, the growth-related characteristics have direct relationship to both, quantity and quality of meat. The objective of this study was to evaluate the application of non-linear models to report the growth curve of Santa Inês sheep. Weights of 140 females, born from2010 to 2012, from a single herd at Cravinhos- SP were used. The weights were measured from birth to about one year of age and the ages were grouped together in biweekly classes. The average weight observed at birth was of 3.77±0.92 kg. The non-linear models utilized in the data adjustment were the Brody, Gompertz, Logistic and Von Bertalanffy models, adjusted by the Gauss-Newton method by means of NLIN procedure, available in SAS software. The parameters which compose the functions, Wt (kg is the weight in time t (days; A (kg is the asymptotic weight when age tends to infinity; b is an integration constant, related to the initial weights of the animals and not well defined biological interpretation, and k is the maturity rate. The average estimates for A and k, are the most important from an zootechnical parameters point of view, mainly because heavier females tend to create faster growing sheep. All the models evaluated reached convergence. The quality of the models adjustment was done by error mean square (EMS means. From the EMS results , the Gompertz model showed the best adjustment, which indicates increased association between the observed and estimated weights, in spite of the EMS values being quite close in all models, pointing out that all were adequate to report the growth curve from birth to one year of age in females of Santa Inês breed.
Non-linear growth analysis of Sumatera thin tail sheep and its cross breds
Directory of Open Access Journals (Sweden)
Agus Suparyanto
2001-12-01
Full Text Available Growth curve is a figure of individual ability to express its genetic potential to maximum size under the existingenvironmental condition. Three non-linear growth curves, von Bertalanffy, Logistic and Gompertz, were used to analyze the weight-age relationship for five genotypes of sheep. The data were collected from IP2TP Sei Putih, North Sumatera. Num ber of animals which were collected consisted of five genotypes i.e, indigenous Sumatera (n=275, St. Croix (n=571, St. Croix Cross (n=899, Barbados Blackbelly Cross (n=471 and composite (n=740. The three non-linear growth curves were compared to obtain the most suitable curve for describing the shape of growth curves among sheep genotypes. The growth curves of von Bertalanffy fitted better than the others. The results showed that regression parameters of B or M (integral constante were significantly different (P0.05. The data show that there was correlation between A and k.
IDENTIFICATION OF NONLINEAR DYNAMIC SYSTEMS:TIME-FREQUENCY FILTERING AND SKELETON CURVES
Institute of Scientific and Technical Information of China (English)
王丽丽; 张景绘
2001-01-01
The nonlinear behavior varying with the instantaneous response was analyzed through the joint time-frequency analysis method for a class of S. D. O . F nonlinear system.A masking operator on definite regions is defined and two theorems are presented. Based on these, the nonlinear system is modeled with a special time-varying linear one, called the generalized skeleton linear system ( GSLS ). The frequency skeleton curve and the damping skeleton curve are defined to describe the main feature of the non-linearity as well. More over, an identification method is proposed through the skeleton curves and the time frequency filtering technique.
Bounded Population Growth: A Curve Fitting Lesson.
Mathews, John H.
1992-01-01
Presents two mathematical methods for fitting the logistic curve to population data supplied by the U.S. Census Bureau utilizing computer algebra software to carry out the computations and plot graphs. (JKK)
Latent Growth Curve Models for Biomarkers of the Stress Response
Directory of Open Access Journals (Sweden)
John M. Felt
2017-06-01
Full Text Available Objective: The stress response is a dynamic process that can be characterized by predictable biochemical and psychological changes. Biomarkers of the stress response are typically measured over time and require statistical methods that can model change over time. One flexible method of evaluating change over time is the latent growth curve model (LGCM. However, stress researchers seldom use the LGCM when studying biomarkers, despite their benefits. Stress researchers may be unaware of how these methods can be useful. Therefore, the purpose of this paper is to provide an overview of LGCMs in the context of stress research. We specifically highlight the unique benefits of using these approaches.Methods: Hypothetical examples are used to describe four forms of the LGCM.Results: The following four specifications of the LGCM are described: basic LGCM, latent growth mixture model, piecewise LGCM, and LGCM for two parallel processes. The specifications of the LGCM are discussed in the context of the Trier Social Stress Test. Beyond the discussion of the four models, we present issues of modeling nonlinear patterns of change, assessing model fit, and linking specific research questions regarding biomarker research using different statistical models.Conclusions: The final sections of the paper discuss statistical software packages and more advanced modeling capabilities of LGCMs. The online Appendix contains example code with annotation from two statistical programs for the LCGM.
Bhowmick, Amiya Ranjan; Bhattacharya, Sabyasachi
2014-08-01
Growth of living organisms is a fundamental biological process. It depicts the physiological development of the species related to the environment. Mathematical development of growth curve models has a long history since its birth. We propose a mathematical model to describe the evolution of relative growth rate as a function of time based on a real life experiment on a major Indian Carp Cirrhinus mrigala. We establish that the proposed model is able to describe the fish growth dynamics more accurately for our experimental data than some existing models e.g. logistic, Gompertz, exponential. Approximate expressions of the points of inflection and the time of achieving the maximum relative growth rate are derived. We study, in detail, the existence of a nonlinear least squares estimator of the model parameters and their consistency properties. Test-statistics is developed to study the equality of points of inflection and equality of the amount of time necessary to achieve the maximum relative growth rate for a species at two different locations. Using the theory of variance stabilizing transformations, we propose a new test statistic to test the effect of the decay parameter for the proposed growth law. The testing procedure is found to be more sensitive in comparison with the test based on nonlinear least squares estimates. Our proposed model provides a general framework to model growth in other disciplines as well.
Nonlinear Latent Curve Models for Multivariate Longitudinal Data
Blozis, Shelley A.; Conger, Katherine J.; Harring, Jeffrey R.
2007-01-01
Latent curve models have become a useful approach to analyzing longitudinal data, due in part to their allowance of and emphasis on individual differences in features that describe change. Common applications of latent curve models in developmental studies rely on polynomial functions, such as linear or quadratic functions. Although useful for…
Institute of Scientific and Technical Information of China (English)
WangLin; NiQiao; HuangYuying
2003-01-01
This paper proposes a new method for investigating the Hopf bifurcation of a curved pipe conveying fluid with nonlinear spring support. The nonlinear equation of motion is derived by forces equilibrium on microelement of the system under consideration. The spatial coordinate of the system is discretized by the differential quadrature method and then the dynamic equation is solved by the Newton-Raphson method. The numerical solutions show that the inner fluid velocity of the Hopf bifurcation point of the curved pipe varies with different values of the parameter,nonlinear spring stiffness. Based on this, the cycle and divergent motions are both found to exist at specific fluid flow velocities with a given value of the nonlinear spring stiffness. The results are useful for further study of the nonlinear dynamic mechanism of the curved fluid conveying pipe.
Modelling Growth Curves in a Nondescript Italian Chicken Breed
National Research Council Canada - National Science Library
Maria Selvaggi; Vito Laudadio; Cataldo Dario; Vincenzo Tufarelli
2015-01-01
... it. This study was carried out to estimate the parameters of logistic, Gompertz and Richards growth curve models in a nondescript chicken breed population from southern Italy to determine the goodness of fit...
Interactions of Cosmic Rays in the Atmosphere: Growth Curves Revisited
Obermeier, A; Hörandel, J; Müller, D
2013-01-01
Measurements of cosmic-ray abundances on balloons are affected by interactions in the residual atmosphere above the balloon. Corrections for such interactions are particularly important for observations of rare secondary particles such as boron, antiprotons and positrons. These corrections can either be calculated if the relevant cross sections in the atmosphere are known, or may be empirically determined by extrapolation of the "growth curves", i. e. the individual particle intensities as functions of atmospheric depth. The growth-curve technique is particularly attractive for long-duration balloon flights where the periodic daily altitude variations permit rather precise determinations of the corresponding particle intensity variations. We determine growth curves for nuclei from boron (Z=5) to iron (Z=26), using data from the 2006 Arctic balloon flight of the TRACER detector for cosmic-ray nuclei, and we compare the growth curves with predictions from published cross section values. In general, good agreeme...
Modeling growth curves to track growing obesity
Our purpose was to examine the relationship between total physical activity (PA) and PA at various intensity levels with insulin resistance at increasing waist circumference and skinfold thickness levels. Being able to describe growth appropriately and succinctly is important in many nutrition and p...
Kilian, Gladiné; Pieter, Muyshondt; Joris, Dirckx
2016-06-01
Laser Doppler Vibrometry is an intrinsic highly linear measurement technique which makes it a great tool to measure extremely small nonlinearities in the vibration response of a system. Although the measurement technique is highly linear, other components in the experimental setup may introduce nonlinearities. An important source of artificially introduced nonlinearities is the speaker, which generates the stimulus. In this work, two correction methods to remove the effects of stimulus nonlinearity are investigated. Both correction methods were found to give similar results but have different pros and cons. The aim of this work is to investigate the importance of the conical shape of the eardrum as a source of nonlinearity in hearing. We present measurements on flat and indented membranes. The data shows that the curved membrane exhibit slightly higher levels of nonlinearity compared to the flat membrane.
Cigeroglu, Ender; Samandari, Hamed
2014-11-01
Nonlinear free vibration analysis of curved double-walled carbon nanotubes (DWNTs) embedded in an elastic medium is studied in this study. Nonlinearities considered are due to large deflection of carbon nanotubes (geometric nonlinearity) and nonlinear interlayer van der Waals forces between inner and outer tubes. The differential quadrature method (DQM) is utilized to discretize the partial differential equations of motion in spatial domain, which resulted in a nonlinear set of algebraic equations of motion. The effect of nonlinearities, different end conditions, initial curvature, and stiffness of the surrounding elastic medium, and vibrational modes on the nonlinear free vibration of DWCNTs is studied. Results show that it is possible to detect different vibration modes occurring at a single vibration frequency when CNTs vibrate in the out-of-phase vibration mode. Moreover, it is observed that boundary conditions have significant effect on the nonlinear natural frequencies of the DWCNT including multiple solutions.
Seismic Fragility Curves of Industrial Buildings by Using Nonlinear Analysis
Directory of Open Access Journals (Sweden)
Mohamed Nazri Fadzli
2017-01-01
Full Text Available This study presents the steel fragility curves and performance curves of industrial buildings of different geometries. The fragility curves were obtained for different building geometries, and the performance curves were developed based on lateral load, which is affected by the geometry of the building. Three records of far-field ground motion were used for incremental dynamic analysis (IDA, and the design lateral loads for pushover analysis (POA. All designs were based on British Standard (BS 5950; however, Eurocode 8 was preferred for seismic consideration in the analysis because BS 5950 does not specify any seismic provision. The five levels of performance stated by FEMA-273, namely, operational phase, immediate occupancy, damage control, life safety, and collapse prevention (CP were used as main guidelines for evaluating structural performance. For POA, Model 2 had highest base shear, followed by Model 1 and Model 3, even though Model 2 has a smaller structure compared with Model 3. Meanwhile, the fragility curves showed that the probability of reaching or exceeding the CP level of Model 2 is the highest, followed by that of Models 1 and 3.
Kaur, A; Takhar, P S; Smith, D M; Mann, J E; Brashears, M M
2008-10-01
A fractional differential equations (FDEs)-based theory involving 1- and 2-term equations was developed to predict the nonlinear survival and growth curves of foodborne pathogens. It is interesting to note that the solution of 1-term FDE leads to the Weibull model. Nonlinear regression (Gauss-Newton method) was performed to calculate the parameters of the 1-term and 2-term FDEs. The experimental inactivation data of Salmonella cocktail in ground turkey breast, ground turkey thigh, and pork shoulder; and cocktail of Salmonella, E. coli, and Listeria monocytogenes in ground beef exposed at isothermal cooking conditions of 50 to 66 degrees C were used for validation. To evaluate the performance of 2-term FDE in predicting the growth curves-growth of Salmonella typhimurium, Salmonella Enteritidis, and background flora in ground pork and boneless pork chops; and E. coli O157:H7 in ground beef in the temperature range of 22.2 to 4.4 degrees C were chosen. A program was written in Matlab to predict the model parameters and survival and growth curves. Two-term FDE was more successful in describing the complex shapes of microbial survival and growth curves as compared to the linear and Weibull models. Predicted curves of 2-term FDE had higher magnitudes of R(2) (0.89 to 0.99) and lower magnitudes of root mean square error (0.0182 to 0.5461) for all experimental cases in comparison to the linear and Weibull models. This model was capable of predicting the tails in survival curves, which was not possible using Weibull and linear models. The developed model can be used for other foodborne pathogens in a variety of food products to study the destruction and growth behavior.
[Growth and nonlinearity]. Progress report
Energy Technology Data Exchange (ETDEWEB)
Savit, R.
1993-12-31
The research centered on the physics of growth. One particular focus was the spiral patterns seen in excitable media, such as the chemical reaction of Belousov and Zhabatinskii, and the aggregation of the slime mold, Dictyostelium Discoideum. Another area of interest is the statistical roughness of the growth front itself. For example, when growing thin films, the roughness of the surface is very important for the ultimate quality of the film. Besides its direct technological relevance, this problem is intimately connected to many fundamental problems in statistical physics. In addition work was done in the related area of statistical properties of flux-flow motion in superconductors. Substantial progress was also made on techniques and applications of the analysis of complex systems. Methods of time series analysis were generalized to the analysis of complex spatio-temporal patterns. In the examples studied most, turbulence and electroencephalograms, the spatio-temporal patterns are very complex and fleeting, and can easily be misken for random noise. Nevertheless, substantial progress was made in developing and applying methods to these systems that indicate the presence of nonrandom time-varying spatial patterns.
Edge detection of remote sensing image based on nonlinear intensity of curved surface
Institute of Scientific and Technical Information of China (English)
张连蓬; 刘国林; 江涛
2003-01-01
A new edge detector based on the nonlinear intensity of curved surface was proposed. The edge detector describes the largest curvature and the smallest curvature of curved surface, therefore it can reflect the real largest direction of image edge jump. By the new edge detector, it is convenient to calculate the curvature in any direction of the curved surface and the curvature can be used in the identification of edge direction and the feature extraction of objects on remote sensing image.
Visualization of Growth Curve Data from Phenotype MicroarrayExperiments
Energy Technology Data Exchange (ETDEWEB)
Jacobsen, Janet S.; Joyner, Dominique C.; Borglin, Sharon E.; Hazen, Terry C.; Arkin, Adam P.; Bethel, E. Wes
2007-04-19
Phenotype microarrays provide a technology to simultaneouslysurvey the response of an organism to nearly 2,000 substrates, includingcarbon, nitrogen and potassium sources; varying pH; varying saltconcentrations; and antibiotics. In order to more quickly and easily viewand compare the large number of growth curves produced by phenotypemicroarray experiments, we have developed software to produce and displaycolor images, each of which corresponds to a set of 96 growth curves.Using color images to represent growth curves data has proven to be avaluable way to assess experiment quality, compare replicates, facilitatecomparison of the responses of different organisms, and identifysignificant phenotypes. The color images are linked to traditional plotsof growth versus time, as well as to information about the experiment,organism, and substrate. In order to share and view information and dataproject-wide, all information, plots, and data are accessible using onlya Web browser.
Visualization of Growth Curve Data from Phenotype MicroarrayExperiments
Energy Technology Data Exchange (ETDEWEB)
Jacobsen, Janet S.; Joyner, Dominique C.; Borglin, Sharon E.; Hazen, Terry C.; Arkin, Adam P.; Bethel, E. Wes
2007-04-19
Phenotype microarrays provide a technology to simultaneouslysurvey the response of an organism to nearly 2,000 substrates, includingcarbon, nitrogen and potassium sources; varying pH; varying saltconcentrations; and antibiotics. In order to more quickly and easily viewand compare the large number of growth curves produced by phenotypemicroarray experiments, we have developed software to produce and displaycolor images, each of which corresponds to a set of 96 growth curves.Using color images to represent growth curves data has proven to be avaluable way to assess experiment quality, compare replicates, facilitatecomparison of the responses of different organisms, and identifysignificant phenotypes. The color images are linked to traditional plotsof growth versus time, as well as to information about the experiment,organism, and substrate. In order to share and view information and dataproject-wide, all information, plots, and data are accessible using onlya Web browser.
PV Degradation Curves: Non-Linearities and Failure Modes
Energy Technology Data Exchange (ETDEWEB)
Jordan, Dirk C.; Silverman, Timothy J.; Sekulic, Bill; Kurtz, Sarah R.
2016-09-03
Photovoltaic (PV) reliability and durability have seen increased interest in recent years. Historically, and as a preliminarily reasonable approximation, linear degradation rates have been used to quantify long-term module and system performance. The underlying assumption of linearity can be violated at the beginning of the life, as has been well documented, especially for thin-film technology. Additionally, non-linearities in the wear-out phase can have significant economic impact and appear to be linked to different failure modes. In addition, associating specific degradation and failure modes with specific time series behavior will aid in duplicating these degradation modes in accelerated tests and, eventually, in service life prediction. In this paper, we discuss different degradation modes and how some of these may cause approximately linear degradation within the measurement uncertainty (e.g., modules that were mainly affected by encapsulant discoloration) while other degradation modes lead to distinctly non-linear degradation (e.g., hot spots caused by cracked cells or solder bond failures and corrosion). The various behaviors are summarized with the goal of aiding in predictions of what may be seen in other systems.
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.
Stochastic simulation of growth curves of Acidithiobacillus ferrooxidans
Institute of Scientific and Technical Information of China (English)
YANG Yu; PENG Hong; QIU Guan-zhou; LIU Jian-she; HU Yue-hua
2006-01-01
To reveal the low growth rate of Acidithiobacillus ferrooxidans, a stochastic growth model was proposed to analyze growth curves of these bacteria in a batch culture. An algorithm was applied to simulate the bacteria population during lag and exponential phase. The results show that the model moderately fits the experimental data.Further, the mean growth constant (K) of growth curves is obtained by fitting the logarithm of the simulating population data versus the generation numbers with the different initial population number (N0) and initial mean activity of population (A0). When N0 is 300 and 700 respectively, the discrepancy of K value is only 0.91%, however, A0 is 0.34 and 0.38 respectively, the discrepancy of K value is 19.53%. It suggests that the effect of A0 on the lag phase exceeds N0, though both parameters could shorten the lag phase by increasing their values.
Improved Nonlinear Equation Method for Numerical Prediction of Jominy End-Quench Curves
Institute of Scientific and Technical Information of China (English)
SONG Yue-peng; LIU Guo-quan; LIU Sheng-xin; LIU Jian-tao; FENG Cheng-ming
2007-01-01
Without considering the effects of alloying interaction on the Jominy end-quench curves, the prediction results obtained by YU Bai-hai's nonlinear equation method for multi-alloying steels were different from those experimental ones reported in literature. Some alloying elements have marked influence on Jominy end-quench curves of steels. An improved mathematical model for simulating the Jominy end-quench curves is proposed by introducing a parameter named alloying interactions equivalent (Le). With the improved model, the Jominy end-quench curves of steels so obtained agree very well with the experimental ones.
Growth curve registration for evaluating salinity tolerance in barley
Meng, Rui
2017-03-23
Background: Smarthouses capable of non-destructive, high-throughput plant phenotyping collect large amounts of data that can be used to understand plant growth and productivity in extreme environments. The challenge is to apply the statistical tool that best analyzes the data to study plant traits, such as salinity tolerance, or plant-growth-related traits. Results: We derive family-wise salinity sensitivity (FSS) growth curves and use registration techniques to summarize growth patterns of HEB-25 barley families and the commercial variety, Navigator. We account for the spatial variation in smarthouse microclimates and in temporal variation across phenotyping runs using a functional ANOVA model to derive corrected FSS curves. From FSS, we derive corrected values for family-wise salinity tolerance, which are strongly negatively correlated with Na but not significantly with K, indicating that Na content is an important factor affecting salinity tolerance in these families, at least for plants of this age and grown in these conditions. Conclusions: Our family-wise methodology is suitable for analyzing the growth curves of a large number of plants from multiple families. The corrected curves accurately account for the spatial and temporal variations among plants that are inherent to high-throughput experiments.
Growth Curve Models and Applications : Indian Statistical Institute
2017-01-01
Growth curve models in longitudinal studies are widely used to model population size, body height, biomass, fungal growth, and other variables in the biological sciences, but these statistical methods for modeling growth curves and analyzing longitudinal data also extend to general statistics, economics, public health, demographics, epidemiology, SQC, sociology, nano-biotechnology, fluid mechanics, and other applied areas. There is no one-size-fits-all approach to growth measurement. The selected papers in this volume build on presentations from the GCM workshop held at the Indian Statistical Institute, Giridih, on March 28-29, 2016. They represent recent trends in GCM research on different subject areas, both theoretical and applied. This book includes tools and possibilities for further work through new techniques and modification of existing ones. The volume includes original studies, theoretical findings and case studies from a wide range of app lied work, and these contributions have been externally r...
Fitting Nonlinear Curves by use of Optimization Techniques
Hill, Scott A.
2005-01-01
MULTIVAR is a FORTRAN 77 computer program that fits one of the members of a set of six multivariable mathematical models (five of which are nonlinear) to a multivariable set of data. The inputs to MULTIVAR include the data for the independent and dependent variables plus the user s choice of one of the models, one of the three optimization engines, and convergence criteria. By use of the chosen optimization engine, MULTIVAR finds values for the parameters of the chosen model so as to minimize the sum of squares of the residuals. One of the optimization engines implements a routine, developed in 1982, that utilizes the Broydon-Fletcher-Goldfarb-Shanno (BFGS) variable-metric method for unconstrained minimization in conjunction with a one-dimensional search technique that finds the minimum of an unconstrained function by polynomial interpolation and extrapolation without first finding bounds on the solution. The second optimization engine is a faster and more robust commercially available code, denoted Design Optimization Tool, that also uses the BFGS method. The third optimization engine is a robust and relatively fast routine that implements the Levenberg-Marquardt algorithm.
Estimation of the growth curve parameters in Macrobrachium rosenbergii
Nagulu, Banoth; Satyanarayana , Y.; Srinivasa, Rao P.; Gopal , Krishna
2011-01-01
Growth is one of the most important characteristics of cultured species. The objective of this study was to determine the fitness of linear, log linear, polynomial, exponential and Logistic functions to the growth curves of Macrobrachium rosenbergii obtained by using weekly records of live weight, total length, head length, claw length, and last segment length from 20 to 192 days of age. The models were evaluated according to the coefficient of determination (R2), and error sum off square (ES...
Ko, William L.; Fleischer, Van Tran; Lung, Shun-Fat
2017-01-01
For shape predictions of structures under large geometrically nonlinear deformations, Curved Displacement Transfer Functions were formulated based on a curved displacement, traced by a material point from the undeformed position to deformed position. The embedded beam (depth-wise cross section of a structure along a surface strain-sensing line) was discretized into multiple small domains, with domain junctures matching the strain-sensing stations. Thus, the surface strain distribution could be described with a piecewise linear or a piecewise nonlinear function. The discretization approach enabled piecewise integrations of the embedded-beam curvature equations to yield the Curved Displacement Transfer Functions, expressed in terms of embedded beam geometrical parameters and surface strains. By entering the surface strain data into the Displacement Transfer Functions, deflections along each embedded beam can be calculated at multiple points for mapping the overall structural deformed shapes. Finite-element linear and nonlinear analyses of a tapered cantilever tubular beam were performed to generate linear and nonlinear surface strains and the associated deflections to be used for validation. The shape prediction accuracies were then determined by comparing the theoretical deflections with the finiteelement- generated deflections. The results show that the newly developed Curved Displacement Transfer Functions are very accurate for shape predictions of structures under large geometrically nonlinear deformations.
Modeling Fractal Dimension Curve of Urban Growth in Developing Countries
Chen, Yanguang
2016-01-01
The growth curve of fractal dimension of cities can be described with sigmoid function such as Boltzmann's equation and logistic function. The logistic models of fractal dimension curves have been presented for the cities in developed countries. However, these models cannot be well fitted to the observational data of fractal dimension of urban form in developing countries (e.g. China). By statistic experiments of fractal parameters, we find that the quadratic Boltzmann's equation can be used to describe fractal dimension change of Chinese cities. For the normalized fractal dimension values, the Boltzmann's equation can be reduced to a quadratic logistic function. In practice, a fractal dimension dataset of urban growth can be approximately fitted with the quadratic logistic function. Thus, a series of models of fractal dimension curve can be proposed for the cities in developing countries. The models are applied to the city of Beijing, Chinese capital, and yield satisfying trend lines of the observational dat...
Characterization of commercial and biological growth curves in the Segureña sheep breed.
Lupi, T M; Nogales, S; León, J M; Barba, C; Delgado, J V
2015-08-01
Non-linear models were analysed to describe both the biological and commercial growth curves of the Segureña sheep, one of the most important Spanish breeds. We evaluated Brody, von Bertalanffy, Verhulst, logistic and Gompertz models, using historical data from the National Association of Segureña Sheep Breeders (ANCOS). These records were collected between 2000 and 2013, from a total of 129 610 weight observations ranging from birth to adulthood. The aim of this research was to establish the mathematical behaviour of body development throughout this breed's commercial life (birth to slaughter) and biological life (birth to adulthood); comparison between both slopes gives important information regarding the best time for slaughter, informs dietary advice according to animals' needs, permits economical predictions of productions and, by using the curve parameters as selection criteria, enables improvements in growth characteristics of the breed. Models were fitted according to the non-linear regression procedure of statistical package SPSS version19. Model parameters were estimated using the Levenberg-Marquardt algorithm. Candidate models were compared using the determinative coefficient, mean square error, number of iterations, Akaike information coefficient and biological coherence of the estimated parameters. The von Bertalanffy and logistic models were found to be best suited to the biological and commercial growth curves, respectively, for both sexes. The Brody equation was found to be unsuitable for studying the commercial growth curve. Differences between the parameters in both sexes indicate a strong impact of sexual dimorphism on growth. This can emphasize the value of the highest growth rate for females, indicating that they reach maturity earlier.
Mediation Analysis in a Latent Growth Curve Modeling Framework
von Soest, Tilmann; Hagtvet, Knut A.
2011-01-01
This article presents several longitudinal mediation models in the framework of latent growth curve modeling and provides a detailed account of how such models can be constructed. Logical and statistical challenges that might arise when such analyses are conducted are also discussed. Specifically, we discuss how the initial status (intercept) and…
Twelve Frequently Asked Questions about Growth Curve Modeling
Curran, Patrick J.; Obeidat, Khawla; Losardo, Diane
2010-01-01
Longitudinal data analysis has long played a significant role in empirical research within the developmental sciences. The past decade has given rise to a host of new and exciting analytic methods for studying between-person differences in within-person change. These methods are broadly organized under the term "growth curve models." The…
Diagnostics of Robust Growth Curve Modeling Using Student's "t" Distribution
Tong, Xin; Zhang, Zhiyong
2012-01-01
Growth curve models with different types of distributions of random effects and of intraindividual measurement errors for robust analysis are compared. After demonstrating the influence of distribution specification on parameter estimation, 3 methods for diagnosing the distributions for both random effects and intraindividual measurement errors…
On Fitting Nonlinear Latent Curve Models to Multiple Variables Measured Longitudinally
Blozis, Shelley A.
2007-01-01
This article shows how nonlinear latent curve models may be fitted for simultaneous analysis of multiple variables measured longitudinally using Mx statistical software. Longitudinal studies often involve observation of several variables across time with interest in the associations between change characteristics of different variables measured…
Flow-Induced Vibration of A Nonlinearly Restrained Curved Pipe Conveying Fluid
Institute of Scientific and Technical Information of China (English)
王琳; 倪樵; 黄玉盈
2004-01-01
Investigated in this study is the flow-induced vibration of a nonlinearly restrained curved pipe conveying fluid. The nonlinear equation of motion is derived by equilibrium of forces on microelement of the system under consideration. The spatial coordinate of the system is discretized by DQM (differential quadrature method). On the basis of the boundary conditions, the dynamic equation is solved by the Newton-Raphson iteration method. The numerical solutions reveal several complex dynamic motions for the variation of the fluid velocity parameter, such as limit cycle motion, buckling and so on. The result obtained also shows that the sub parameter regions corresponding to the several motions may change with the variation of some parameters of the curved pipe. The present study supplies a new reference for investigating the nonlinear dynamic response of some other structures.
Duc, Nguyen Dinh; Quan, Tran Quoc
2012-09-01
An analytical investigation into the nonlinear response of thick functionally graded double-curved shallow panels resting on elastic foundations and subjected to thermal and thermomechanical loads is presented. Young's modulus and Poisson's ratio are both graded in the thickness direction according to a simple power-law distribution in terms of volume fractions of constituents. All formulations are based on the classical shell theory with account of geometrical nonlinearity and initial geometrical imperfection in the cases of Pasternak-type elastic foundations. By applying the Galerkin method, explicit relations for the thermal load-deflection curves of simply supported curved panels are found. The effects of material and geometrical properties and foundation stiffness on the buckling and postbuckling load-carrying capacity of the panels in thermal environments are analyzed and discussed.
ECONOMIC GROWTH, TRADE AND ENVIRONMENTAL ISSUES: TESTING ENVIRONMENTAL KUZNETS CURVE
Directory of Open Access Journals (Sweden)
Dedi Budiman Hakim
2013-04-01
Full Text Available ASEAN experiences a dynamic economic growth due to its liberalised markets. However concerns arise related to environmental issues resulting from the economic activities. It reflects tradeoffs between economic growth driven by trade and foreign direct investment (FDI, and environment. To investigate such a relation the Environmental Kuznets Curve was applied by regressing amount of carbon emission with gross domestic product (GDP, quadratic GDP, trade openness and FDI. The result reveals that amount of carbon emission is linearly and positively correlated with GDP per capita. It is predicted that as ASEAN economies grow, carbon emission increases. Trade openness is also found to contribute to carbon emission. Keywords: Kuznets curve, carbon emission, gross domestic product, trade, foreign direct investment JEL classification number: F15, F18
Environmental Kuznets curve and growth source in Iran
Directory of Open Access Journals (Sweden)
Asghari Maryam
2012-01-01
Full Text Available Recent empirical research has examined the relationship between certain indicators of environmental degradation and income, concluding that in some cases an inverted U-shaped relationship, which has been called an environmental Kuznets curve (EKC, exists between these variables. The source of growth explanation is important for two reasons. First, it demonstrates how the pollution consequences of growth depend on the source of growth. Therefore, the analogy drawn by some in the environmental community between the damaging effects of economic development and those of liberalized trade is, at best, incomplete. Second, the source of growth explanation demonstrates that a strong policy response to income gains is not necessary for pollution to fall with growth. The aim of this paper investigates the role of differences source of growth in environmental quality of Iran. The results show the two growth resources in Iran cause, in the early stages, CO2 emission decreases until turning point but beyond this level of income per capita, economic growth leads to environmental degradation. I find a U relationship between environmental degradation (CO2 emission and economic growth in Iran.
A theoretical and experimental study on geometric nonlinearity of initially curved cantilever beams
Directory of Open Access Journals (Sweden)
Sushanta Ghuku
2016-03-01
Full Text Available This paper presents a theoretical and experimental study on large deflection behavior of initially curved cantilever beams subjected to various types of loadings. The physical system as a straight cantilever beam subjected to a tip concentrated load is considered in this study. Nonlinear differential equations are obtained for large deflection analysis of such a straight cantilever beam, and this problem is known to involve geometrical nonlinearity. The equations are solved numerically with the help of MATLAB® computational platform to get deflection profiles of the concerned problem. These results are imposed subsequently on the center line of an initially curved beam to get theoretical load-deflection behavior of curved beam problems. To verify the theoretical model, experiment is carried out with the master leaf of a leaf spring bundle by modeling it as an initially curved cantilever beam. The effects of initial clamping and geometry variations in the eye-region are observed from experimental investigation which is commonly neglected in the mathematical formulation. Comparisons of the theoretical results with the experimental results are quite good, but the avenues for further improvement are also reported. The proposed approach is further extended to study large deflection behavior of an initially curved cantilever beam subjected to distributed and combined load. These results are successfully validated with existing results for straight beams and some new results are furnished for initially curved cantilever beams.
Growth Curves Analysis of Five Meat Rabbit Breeds
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The growth curves of five meat rabbit breeds are fitted in form of Gompertz model. The results are shown as follows :the goodness of fit is higher than 99.50% ;considering the body weight at one hundred day.the maximum weight (A)、the instantaneous relative growth rate (K)、the turning weight (W*)、 the turning age (t*)、the early average daily gain (KW*) selection,the Checkered Giant (GG) and the New Zealand White (NN) are better than other meat breeds,the slauthter age should be at the age of 90 day.
Genetic analysis of growth curves using the SAEM algorithm
Directory of Open Access Journals (Sweden)
Lavielle Marc
2006-11-01
Full Text Available Abstract The analysis of nonlinear function-valued characters is very important in genetic studies, especially for growth traits of agricultural and laboratory species. Inference in nonlinear mixed effects models is, however, quite complex and is usually based on likelihood approximations or Bayesian methods. The aim of this paper was to present an efficient stochastic EM procedure, namely the SAEM algorithm, which is much faster to converge than the classical Monte Carlo EM algorithm and Bayesian estimation procedures, does not require specification of prior distributions and is quite robust to the choice of starting values. The key idea is to recycle the simulated values from one iteration to the next in the EM algorithm, which considerably accelerates the convergence. A simulation study is presented which confirms the advantages of this estimation procedure in the case of a genetic analysis. The SAEM algorithm was applied to real data sets on growth measurements in beef cattle and in chickens. The proposed estimation procedure, as the classical Monte Carlo EM algorithm, provides significance tests on the parameters and likelihood based model comparison criteria to compare the nonlinear models with other longitudinal methods.
Lmfit: Non-Linear Least-Square Minimization and Curve-Fitting for Python
Newville, Matthew; Stensitzki, Till; Allen, Daniel B.; Rawlik, Michal; Ingargiola, Antonino; Nelson, Andrew
2016-06-01
Lmfit provides a high-level interface to non-linear optimization and curve fitting problems for Python. Lmfit builds on and extends many of the optimization algorithm of scipy.optimize, especially the Levenberg-Marquardt method from optimize.leastsq. Its enhancements to optimization and data fitting problems include using Parameter objects instead of plain floats as variables, the ability to easily change fitting algorithms, and improved estimation of confidence intervals and curve-fitting with the Model class. Lmfit includes many pre-built models for common lineshapes.
Testing the Nonlinearity of the Phillips Curve. Implications for Monetary Policy
Directory of Open Access Journals (Sweden)
Georgiana BALABAN
2010-04-01
Full Text Available This paper studies the nonlinearity of the Phillips Curve and its implications for monetary policy. To investigate the trade-off between output gap and inflation volatility we used a backward-looking model type. The data for our empirical analysis is obtained from the Area Wide Model (AWM Database (from 1970 to 2008 for Euro area and National Institute of Statistics (from 2000 to 2009 for Romania and has quarterly frequency. The results of econometric tests indicate a significant estimated coefficient of the output gap for Romania, compared with the Eurozone; we find no significant evidence of nonlinearity of the Phillips curve in the European Monetary Union. This suggests that the optimal choice for European Central Bank should be a fixed inflation targeting, while the National Bank of Romania's monetary policy strategy should aim a flexible inflation targeting.
The Nonlinearity of the New Keynesian Phillips Curve: The Case of Tunisia
Directory of Open Access Journals (Sweden)
Imen Kobbi
2017-07-01
Full Text Available This article seeks to check the nonlinearity of the Phillips curve in Tunisia for the 1993–2012 period, relying on a hybrid new Keynesian Phillips curve modeled via a Logistic Smooth Transition Regression (LSTR model with endogenous variables. We estimate this model using the nonlinear instrumental variables. The empirical results corroborate the new Keynesian assumption ofprice rigidity and show that the response of inflation to the output gap tends to be significant only if the inflation rate tends to be relatively high and exceeds a certain threshold. For a low inflation rate, the price rigidity dominates. This result is particularly evident in Tunisia, especially for the years following the 2011 revolution during which the elasticity of inflation rate to an excess demand has become highly important and the inflation rate experienced record levels.
Intrinsic localized modes and nonlinear impurity modes in curved Fermi-Pasta-Ulam chain
Indian Academy of Sciences (India)
Ranja Sarkar; Bishwajyoti Dey
2008-06-01
We explore the nature of intrinsic localized modes (ILMs) in a curved FermiPasta-Ulam (FPU) chain and the effects of geometry and second-neighbor interaction on the localization and movability properties of such modes. We determine analytically the structure of the localized modes induced by an isotopic light-mass impurity in this chain. We further demonstrate that a nonlinear impurity mode may be treated as a bound state of an ILM with the impurity.
On the analysis of Canadian Holstein dairy cow lactation curves using standard growth functions.
López, S; France, J; Odongo, N E; McBride, R A; Kebreab, E; AlZahal, O; McBride, B W; Dijkstra, J
2015-04-01
Six classical growth functions (monomolecular, Schumacher, Gompertz, logistic, Richards, and Morgan) were fitted to individual and average (by parity) cumulative milk production curves of Canadian Holstein dairy cows. The data analyzed consisted of approximately 91,000 daily milk yield records corresponding to 122 first, 99 second, and 92 third parity individual lactation curves. The functions were fitted using nonlinear regression procedures, and their performance was assessed using goodness-of-fit statistics (coefficient of determination, residual mean squares, Akaike information criterion, and the correlation and concordance coefficients between observed and adjusted milk yields at several days in milk). Overall, all the growth functions evaluated showed an acceptable fit to the cumulative milk production curves, with the Richards equation ranking first (smallest Akaike information criterion) followed by the Morgan equation. Differences among the functions in their goodness-of-fit were enlarged when fitted to average curves by parity, where the sigmoidal functions with a variable point of inflection (Richards and Morgan) outperformed the other 4 equations. All the functions provided satisfactory predictions of milk yield (calculated from the first derivative of the functions) at different lactation stages, from early to late lactation. The Richards and Morgan equations provided the most accurate estimates of peak yield and total milk production per 305-d lactation, whereas the least accurate estimates were obtained with the logistic equation. In conclusion, classical growth functions (especially sigmoidal functions with a variable point of inflection) proved to be feasible alternatives to fit cumulative milk production curves of dairy cows, resulting in suitable statistical performance and accurate estimates of lactation traits. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Tracing Analytic Ray Curves for Light and Sound Propagation in Non-Linear Media.
Mo, Qi; Yeh, Hengchin; Manocha, Dinesh
2016-11-01
The physical world consists of spatially varying media, such as the atmosphere and the ocean, in which light and sound propagates along non-linear trajectories. This presents a challenge to existing ray-tracing based methods, which are widely adopted to simulate propagation due to their efficiency and flexibility, but assume linear rays. We present a novel algorithm that traces analytic ray curves computed from local media gradients, and utilizes the closed-form solutions of both the intersections of the ray curves with planar surfaces, and the travel distance. By constructing an adaptive unstructured mesh, our algorithm is able to model general media profiles that vary in three dimensions with complex boundaries consisting of terrains and other scene objects such as buildings. Our analytic ray curve tracer with the adaptive mesh improves the efficiency considerably over prior methods. We highlight the algorithm's application on simulation of visual and sound propagation in outdoor scenes.
Growth curve of buffalo grazing on a grass pasture
Directory of Open Access Journals (Sweden)
Teresa Cristina Alves
2015-09-01
Full Text Available ABSTRACTThe objective of this study was to evaluate the performance of 17 buffaloes (Mediterranean, from birth to slaughter age (720 days with monthly measures of weight, thoracic perimeter, body length, and height at withers. At the end of experimental period, the animals were separated into two different groups for statistical analysis according to slaughter weight: light body weight (LBW, mean 517 kg and heavy body weight (HBW, mean 568 kg. Buffalo growth occurs in the same way up to weaning age, and after that, two distinct groups grow in different forms in the same conditions of management and feeding. Body weight can be estimated according to age, thoracic perimeter, height, and length, showing high correlations. Buffaloes show growth in a sigmoid-curve model.
Academia-industry collaboration feeds exponential growth curve
Jones Bey Hassaun, A
2004-01-01
The use of silicon strip detectors in high-energy particle tracking is discussed. The functional strength of silicon for high-energy particle physics as well as astrophysics lies in the ability to detect passage of charged particles with micron-scale spatial resolution. In addition to vertex detection, silicon strip detectors also provide full tracking detection to include momentum determination of particles in the magnetic field. Even if silicon detectors for basic science applications do not continue to grow larger, exponential growth of the technology for terrestrial commercial applications is likely to follow a healthy growth curve, as researchers continue to adapt silicon detector technology for low- dose medical x-ray imaging. (Edited abstract)
Multi-Trait GWAS and New Candidate Genes Annotation for Growth Curve Parameters in Brahman Cattle.
Crispim, Aline Camporez; Kelly, Matthew John; Guimarães, Simone Eliza Facioni; Fonseca e Silva, Fabyano; Fortes, Marina Rufino Salinas; Wenceslau, Raphael Rocha; Moore, Stephen
2015-01-01
Understanding the genetic architecture of beef cattle growth cannot be limited simply to the genome-wide association study (GWAS) for body weight at any specific ages, but should be extended to a more general purpose by considering the whole growth trajectory over time using a growth curve approach. For such an approach, the parameters that are used to describe growth curves were treated as phenotypes under a GWAS model. Data from 1,255 Brahman cattle that were weighed at birth, 6, 12, 15, 18, and 24 months of age were analyzed. Parameter estimates, such as mature weight (A) and maturity rate (K) from nonlinear models are utilized as substitutes for the original body weights for the GWAS analysis. We chose the best nonlinear model to describe the weight-age data, and the estimated parameters were used as phenotypes in a multi-trait GWAS. Our aims were to identify and characterize associated SNP markers to indicate SNP-derived candidate genes and annotate their function as related to growth processes in beef cattle. The Brody model presented the best goodness of fit, and the heritability values for the parameter estimates for mature weight (A) and maturity rate (K) were 0.23 and 0.32, respectively, proving that these traits can be a feasible alternative when the objective is to change the shape of growth curves within genetic improvement programs. The genetic correlation between A and K was -0.84, indicating that animals with lower mature body weights reached that weight at younger ages. One hundred and sixty seven (167) and two hundred and sixty two (262) significant SNPs were associated with A and K, respectively. The annotated genes closest to the most significant SNPs for A had direct biological functions related to muscle development (RAB28), myogenic induction (BTG1), fetal growth (IL2), and body weights (APEX2); K genes were functionally associated with body weight, body height, average daily gain (TMEM18), and skeletal muscle development (SMN1). Candidate
Growth Curve Analysis and Change-Points Detection in Extremes
Meng, Rui
2016-05-15
The thesis consists of two coherent projects. The first project presents the results of evaluating salinity tolerance in barley using growth curve analysis where different growth trajectories are observed within barley families. The study of salinity tolerance in plants is crucial to understanding plant growth and productivity. Because fully-automated smarthouses with conveyor systems allow non-destructive and high-throughput phenotyping of large number of plants, it is now possible to apply advanced statistical tools to analyze daily measurements and to study salinity tolerance. To compare different growth patterns of barley variates, we use functional data analysis techniques to analyze the daily projected shoot areas. In particular, we apply the curve registration method to align all the curves from the same barley family in order to summarize the family-wise features. We also illustrate how to use statistical modeling to account for spatial variation in microclimate in smarthouses and for temporal variation across runs, which is crucial for identifying traits of the barley variates. In our analysis, we show that the concentrations of sodium and potassium in leaves are negatively correlated, and their interactions are associated with the degree of salinity tolerance. The second project studies change-points detection methods in extremes when multiple time series data are available. Motived by the scientific question of whether the chances to experience extreme weather are different in different seasons of a year, we develop a change-points detection model to study changes in extremes or in the tail of a distribution. Most of existing models identify seasons from multiple yearly time series assuming a season or a change-point location remains exactly the same across years. In this work, we propose a random effect model that allows the change-point to vary from year to year, following a given distribution. Both parametric and nonparametric methods are developed
Directory of Open Access Journals (Sweden)
H. Vazquez-Leal
2014-01-01
Full Text Available We present a homotopy continuation method (HCM for finding multiple operating points of nonlinear circuits composed of devices modelled by using piecewise linear (PWL representations. We propose an adaptation of the modified spheres path tracking algorithm to trace the homotopy trajectories of PWL circuits. In order to assess the benefits of this proposal, four nonlinear circuits composed of piecewise linear modelled devices are analysed to determine their multiple operating points. The results show that HCM can find multiple solutions within a single homotopy trajectory. Furthermore, we take advantage of the fact that homotopy trajectories are PWL curves meant to replace the multidimensional interpolation and fine tuning stages of the path tracking algorithm with a simple and highly accurate procedure based on the parametric straight line equation.
Directory of Open Access Journals (Sweden)
Fernanda Gomes da Silveira
2011-04-01
Full Text Available Este estudo teve como objetivo utilizar a análise de agrupamento para classificar modelos de regressão não-lineares usados para descrever a curva de crescimento de ovinos cruzados, tendo em vista os resultados de diferentes avaliadores de qualidade de ajuste. Para tanto, utilizaram-se dados de peso-idade dos seguintes cruzamentos entre raças de ovinos de corte: Dorper x Morada Nova, Dorper x Rabo Largo e Dorper x Santa Inês. Após a indicação do melhor modelo, objetivou-se ainda aplicar a técnica de identidade de modelos a fim de identificar o cruzamento mais produtivo. Foram ajustados doze modelos não-lineares, cuja qualidade de ajuste foi medida pelo coeficiente de determinação ajustado, critérios de informação de Akaike e Bayesiano, erro quadrático médio de predição e coeficiente de determinação de predição. A análise de agrupamento indicou o modelo Richards como o mais adequado para descrever as curvas de crescimento dos três grupos genéticos considerados, e os testes de identidade de modelos indicaram o cruzamento Dorper x Santa Inês como sendo o mais indicado para a pecuária local.This study had the objectives to use the cluster analysis in order to classify nonlinear regression models used to describe the growth curve in relation to different quality fit evaluators. Were utilized weight-age data from the following crossbred beef lambs Dorper x Morada Nova, Dorper x Rabo Largo e Dorper x Santa Inês. After the choice of the best model, we aimed also to apply the model identity in order to identify the most efficient crossbred group. Eleven nonlinear models were used, whose fit quality was measured by determination coefficient, Akaike information criterion, Bayesian information criterion, mean quadratic error of prediction and predicted determination coefficient. The cluster analysis indicated the Richards as the best model for the three data sets, and the model identity tests revealed that the Dorper x Santa In
Nonlinear Radiative Heat Transfer in Blasius and Sakiadis Flows Over a Curved Surface
Naveed, M.; Abbas, Z.; Sajid, M.
2017-01-01
This study investigates the heat transfer characteristics for Blasius and Sakiadis flows over a curved surface coiled in a circle of radius R having constant curvature. Effects of thermal radiation are also analyzed for nonlinear Rosseland approximation which is valid for all values of the temperature difference between the fluid and the surface. The considered physical situation is represented by a mathematical model using curvilinear coordinates. Similar solutions of the developed partial differential equations are evaluated numerically using a shooting algorithm. Fluid velocity, skin-friction coefficient, temperature and local Nusselt number are the quantities of interest interpreted for the influence of pertinent parameters. A comparison of the present and the published data for a flat surface validates the obtained numerical solution for the curved geometry.
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Danielle L. Morton
2017-01-01
Full Text Available Objective. Infants with intestinal failure or feeding intolerance are nutritionally compromised and are at risk for extrauterine growth restriction. The aim of the study was to evaluate growth velocities of infants with intestinal failure and feeding intolerance for the first three months of age and to determine growth percentiles at birth and at 40-week postmenstrual age (PMA. Methods. A chart review of infants followed by the Texas Children’s Hospital Intestinal Rehabilitation Team was conducted from April 2012 to October 2014. Weekly weight, length, and head circumference growth velocities were calculated. Growth data were compared to Olsen growth curves to determine exact percentiles. Results. Data from infants (n=164 revealed that average growth velocities of 3-month-old infants (weight gain, 19.97 g/d; length, 0.81 cm/week; head circumference, 0.52 cm/week fluctuated and all were below expected norms. At discharge or death, average growth velocities had further decreased (length, 0.69 cm/week; head circumference, 0.45 cm/week except for weight, which showed a slight increase (weight, 20.56 g/d. Weight, length, and head circumference percentiles significantly decreased from birth to 40-week PMA (P<0.001. Conclusions. Growth of infants with intestinal failure or feeding intolerance did not follow standard growth curves.
Economic growth and energy regulation in the environmental Kuznets curve.
Lorente, Daniel Balsalobre; Álvarez-Herranz, Agustín
2016-08-01
This study establishes the existence of a pattern of behavior, between economic growth and environmental degradation, consistent with the environmental Kuznets curve (EKC) hypothesis for 17 Organization for Economic Cooperation and Development (OECD) countries between 1990 and 2012. Based on this EKC pattern, it shows that energy regulation measures help reduce per capita greenhouse gas (GHG) emissions. To validate this hypothesis, we also add the explanatory variables: renewable energy promotion, energy innovation processes, and the suppression effect of income level on the contribution of renewable energy sources to total energy consumption. It aims to be a tool for decision-making regarding energy policy. This paper provides a two-stage econometric analysis of instrumental variables with the aim of correcting the existence of endogeneity in the variable GDP per capita, verifying that the instrumental variables used in this research are appropriate for our aim. To this end, it first makes a methodological contribution before incorporating additional variables associated with environmental air pollution into the EKC hypothesis and showing how they positively affect the explanation of the correction in the GHG emission levels. This study concludes that air pollution will not disappear on its own as economic growth increases. Therefore, it is necessary to promote energy regulation measures to reduce environmental pollution.
DEFF Research Database (Denmark)
Tan, Qihua; Thomassen, Mads; Hjelmborg, Jacob V B
2011-01-01
among fractional polynomial models with power terms from a set of fixed values that offer a wide range of curve shapes and suggests a best fitting model. After a limited simulation study, the model has been applied to our human in vivo irritated epidermis data with missing observations to investigate......-course pattern in a gene by gene manner. We introduce a growth curve model with fractional polynomials to automatically capture the various time-dependent expression patterns and meanwhile efficiently handle missing values due to incomplete observations. For each gene, our procedure compares the performances...... time-dependent transcriptional responses to a chemical irritant. Our method was able to identify the various nonlinear time-course expression trajectories. The integration of growth curves with fractional polynomials provides a flexible way to model different time-course patterns together with model...
Morton, Danielle L.; Hawthorne, Keli M.
2017-01-01
Objective. Infants with intestinal failure or feeding intolerance are nutritionally compromised and are at risk for extrauterine growth restriction. The aim of the study was to evaluate growth velocities of infants with intestinal failure and feeding intolerance for the first three months of age and to determine growth percentiles at birth and at 40-week postmenstrual age (PMA). Methods. A chart review of infants followed by the Texas Children's Hospital Intestinal Rehabilitation Team was conducted from April 2012 to October 2014. Weekly weight, length, and head circumference growth velocities were calculated. Growth data were compared to Olsen growth curves to determine exact percentiles. Results. Data from infants (n = 164) revealed that average growth velocities of 3-month-old infants (weight gain, 19.97 g/d; length, 0.81 cm/week; head circumference, 0.52 cm/week) fluctuated and all were below expected norms. At discharge or death, average growth velocities had further decreased (length, 0.69 cm/week; head circumference, 0.45 cm/week) except for weight, which showed a slight increase (weight, 20.56 g/d). Weight, length, and head circumference percentiles significantly decreased from birth to 40-week PMA (P feeding intolerance did not follow standard growth curves.
Description of the growth curve for Angus pasture-fed cows under extensive systems.
Goldberg, V; Ravagnolo, O
2015-09-01
Growth curves are useful for describing the sigmoid shape of an animal's weight pattern over time. The purpose of the present study was to describe, for the first time, a complete growth curve for pasture-fed Angus cows in Uruguay and to analyze the major fixed effects that affect the estimation of mature cow weight (CW). A total of 22,743 records from 5,284 cows belonging to 73 herds were used in the statistical analysis. Five nonlinear models (Brody, Gompertz, Von Bertalanffy, logistic, and Richards) and a 3-knot cubic spline function were fitted to model weight change across age. Body weights were recorded at birth, weaning, and 18 mo and as an adult (at 2.3-3.6, 3.6-4.6, 4.6 to 5.6, 5.6 to 6.6, and 6.6 to 8.1 yr). After preliminary analyses, the fixed effects included in the model to estimate CW were BCS, herd, year and month of measurement, and age of dam. The herd and BCS were the major significant sources of variation. The Richards model had the lowest values for Akaike information criterion, Bayesian information criterion, and -2 log likelihood, with the asymptotic weight being 542 kg. The spline function was the model that fitted the data most closely to the observed weights followed by the Richards function. The Richards model gave better predictions of weights from birth to maturity than the other 4 nonlinear models, because these functions were shown to over- or underestimate weights at different ages in this beef cattle data set. The predicted curve showed that cows reach mature CW after 5 yr of age, which is the age commonly assumed as adult weight in beef cattle. Results form this analysis allowed the estimation of CW and rate of maturing and to take knowledge of the shape of growth curve for Angus females in Uruguay under extensive conditions, helping breeders to take selection decisions. In this way, breeders can optimize the management and efficiency for each production system.
Nonlinear Analysis and Post-Test Correlation for a Curved PRSEUS Panel
Gould, Kevin; Lovejoy, Andrew E.; Jegley, Dawn; Neal, Albert L.; Linton, Kim, A.; Bergan, Andrew C.; Bakuckas, John G., Jr.
2013-01-01
The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept, developed by The Boeing Company, has been extensively studied as part of the National Aeronautics and Space Administration's (NASA s) Environmentally Responsible Aviation (ERA) Program. The PRSEUS concept provides a light-weight alternative to aluminum or traditional composite design concepts and is applicable to traditional-shaped fuselage barrels and wings, as well as advanced configurations such as a hybrid wing body or truss braced wings. Therefore, NASA, the Federal Aviation Administration (FAA) and The Boeing Company partnered in an effort to assess the performance and damage arrestments capabilities of a PRSEUS concept panel using a full-scale curved panel in the FAA Full-Scale Aircraft Structural Test Evaluation and Research (FASTER) facility. Testing was conducted in the FASTER facility by subjecting the panel to axial tension loads applied to the ends of the panel, internal pressure, and combined axial tension and internal pressure loadings. Additionally, reactive hoop loads were applied to the skin and frames of the panel along its edges. The panel successfully supported the required design loads in the pristine condition and with a severed stiffener. The panel also demonstrated that the PRSEUS concept could arrest the progression of damage including crack arrestment and crack turning. This paper presents the nonlinear post-test analysis and correlation with test results for the curved PRSEUS panel. It is shown that nonlinear analysis can accurately calculate the behavior of a PRSEUS panel under tension, pressure and combined loading conditions.
Directory of Open Access Journals (Sweden)
Iman Eshraghi
2016-09-01
Full Text Available Imperfection sensitivity of large amplitude vibration of curved single-walled carbon nanotubes (SWCNTs is considered in this study. The SWCNT is modeled as a Timoshenko nano-beam and its curved shape is included as an initial geometric imperfection term in the displacement field. Geometric nonlinearities of von Kármán type and nonlocal elasticity theory of Eringen are employed to derive governing equations of motion. Spatial discretization of governing equations and associated boundary conditions is performed using differential quadrature (DQ method and the corresponding nonlinear eigenvalue problem is iteratively solved. Effects of amplitude and location of the geometric imperfection, and the nonlocal small-scale parameter on the nonlinear frequency for various boundary conditions are investigated. The results show that the geometric imperfection and non-locality play a significant role in the nonlinear vibration characteristics of curved SWCNTs.
Shin, Tacksoo
2012-01-01
This study introduced various nonlinear growth models, including the quadratic conventional polynomial model, the fractional polynomial model, the Sigmoid model, the growth model with negative exponential functions, the multidimensional scaling technique, and the unstructured growth curve model. It investigated which growth models effectively…
Shin, Tacksoo
2012-01-01
This study introduced various nonlinear growth models, including the quadratic conventional polynomial model, the fractional polynomial model, the Sigmoid model, the growth model with negative exponential functions, the multidimensional scaling technique, and the unstructured growth curve model. It investigated which growth models effectively…
Ability of non-linear mixed models to predict growth in laying hens
Directory of Open Access Journals (Sweden)
Luis Fernando Galeano-Vasco
2014-11-01
Full Text Available In this study, the Von Bertalanffy, Richards, Gompertz, Brody, and Logistics non-linear mixed regression models were compared for their ability to estimate the growth curve in commercial laying hens. Data were obtained from 100 Lohmann LSL layers. The animals were identified and then weighed weekly from day 20 after hatch until they were 553 days of age. All the nonlinear models used were transformed into mixed models by the inclusion of random parameters. Accuracy of the models was determined by the Akaike and Bayesian information criteria (AIC and BIC, respectively, and the correlation values. According to AIC, BIC, and correlation values, the best fit for modeling the growth curve of the birds was obtained with Gompertz, followed by Richards, and then by Von Bertalanffy models. The Brody and Logistic models did not fit the data. The Gompertz nonlinear mixed model showed the best goodness of fit for the data set, and is considered the model of choice to describe and predict the growth curve of Lohmann LSL commercial layers at the production system of University of Antioquia.
Integrated healthcare networks' performance: a growth curve modeling approach.
Wan, Thomas T H; Wang, Bill B L
2003-05-01
This study examines the effects of integration on the performance ratings of the top 100 integrated healthcare networks (IHNs) in the United States. A strategic-contingency theory is used to identify the relationship of IHNs' performance to their structural and operational characteristics and integration strategies. To create a database for the panel study, the top 100 IHNs selected by the SMG Marketing Group in 1998 were followed up in 1999 and 2000. The data were merged with the Dorenfest data on information system integration. A growth curve model was developed and validated by the Mplus statistical program. Factors influencing the top 100 IHNs' performance in 1998 and their subsequent rankings in the consecutive years were analyzed. IHNs' initial performance scores were positively influenced by network size, number of affiliated physicians and profit margin, and were negatively associated with average length of stay and technical efficiency. The continuing high performance, judged by maintaining higher performance scores, tended to be enhanced by the use of more managerial or executive decision-support systems. Future studies should include time-varying operational indicators to serve as predictors of network performance.
The Biasing Effects of Unmodeled ARMA Time Series Processes on Latent Growth Curve Model Estimates
Sivo, Stephen; Fan, Xitao; Witta, Lea
2005-01-01
The purpose of this study was to evaluate the robustness of estimated growth curve models when there is stationary autocorrelation among manifest variable errors. The results suggest that when, in practice, growth curve models are fitted to longitudinal data, alternative rival hypotheses to consider would include growth models that also specify…
GROWTH ANALYSIS IN RABBIT USING GOMPERTZ NON-LINEAR MODEL
Directory of Open Access Journals (Sweden)
A. Setiaji
2014-10-01
Full Text Available An experiment was conducted to compare the growth curve of rabbit. Three breeds of rabbit,namely Indonesian Local Rabbit (IL, Flamish Giant (FG and Rex (R were used in the study.Individual body weights of each breed was measured from birth to 63 days of age with 3-days interval.Those periodical data were separated into different sex, be then it was averaged to analysis growthpattern. Growth curve parameters were estimated to fit growth data. There was no difference in bodyweight between sexs within breed. Indonesian local rabbit had the lowest body weight. The resultsshowed that growth curve paramaters among three breeds were significantly different (P<0.05 for bothsexes. FG had the highest value of asymptotic mature weight, followed by R and IL. In conclusion,Gompertz model was excellent fit for the growth data in rabbit with a high coefficient determination (R2= 0.999.
High-resolution fiber optic temperature sensors using nonlinear spectral curve fitting technique
Su, Z. H.; Gan, J.; Yu, Q. K.; Zhang, Q. H.; Liu, Z. H.; Bao, J. M.
2013-04-01
A generic new data processing method is developed to accurately calculate the absolute optical path difference of a low-finesse Fabry-Perot cavity from its broadband interference fringes. The method combines Fast Fourier Transformation with nonlinear curve fitting of the entire spectrum. Modular functions of LabVIEW are employed for fast implementation of the data processing algorithm. The advantages of this technique are demonstrated through high performance fiber optic temperature sensors consisting of an infrared superluminescent diode and an infrared spectrometer. A high resolution of 0.01 °C is achieved over a large dynamic range from room temperature to 800 °C, limited only by the silica fiber used for the sensor.
Variational principle and a perturbative solution of non-linear string equations in curved space
Roshchupkin, S N
1999-01-01
String dynamics in a curved space-time is studied on the basis of an action functional including a small parameter of rescaled tension constant. A rescaled slow worldsheet time $T=\\epsilon\\tau$ is introduced, and general covariant non-linear string equation are derived. It is shown that in the first order of an $\\epsilon $-expansion these equations are reduced to the known equation for geodesic derivation but complemented by a string oscillatory term. These equations are solved for the de Sitter and Friedmann -Robertson-Walker spaces. The primary string constraints are found to be split into a chain of perturbative constraints and their conservation and consistency are proved. It is established that in the proposed realization of the perturbative approach the string dynamics in the de Sitter space is stable for a large Hubble constant $H
Nonlinear Free Vibration Analysis of Thin-walled Curved Beam with Non-symmetric Open Cross Section
Institute of Scientific and Technical Information of China (English)
DUAN Hai-juan; SONG Zhen-sen
2008-01-01
A finite element formulation was presented for the nonlinear free vibration of thin-walled curved beams with non-symmetric open across section. The kinetic and potential energies were derived by the virtual principle. The energy function includes the effect of flexural-torsional coupling, the torsion warping and the shear centre location. For finite element analysis, cubic polynomials were utilized as the shape functions of the two nodal thin-walled curved elements. Each node possesses seven degrees freedom including the warping degree of freedom. The nonlinear eigenvalue problem was solved by the direct iteration technique. The results are compared with those for straight beams as available in the literature. The results for nonlinear free vibration analysis of curved beams for various radii and subtended angle are presented.
Lin, Ying-Tsong; McMahon, Kara G; Lynch, James F; Siegmann, William L
2013-01-01
The acoustic ducting effect by curved nonlinear gravity waves in shallow water is studied through idealized models in this paper. The internal wave ducts are three-dimensional, bounded vertically by the sea surface and bottom, and horizontally by aligned wavefronts. Both normal mode and parabolic equation methods are taken to analyze the ducted sound field. Two types of horizontal acoustic modes can be found in the curved internal wave duct. One is a whispering-gallery type formed by the sound energy trapped along the outer and concave boundary of the duct, and the other is a fully bouncing type due to continual reflections from boundaries in the duct. The ducting condition depends on both internal-wave and acoustic-source parameters, and a parametric study is conducted to derive a general pattern. The parabolic equation method provides full-field modeling of the sound field, so it includes other acoustic effects caused by internal waves, such as mode coupling/scattering and horizontal Lloyd's mirror interference. Two examples are provided to present internal wave ducts with constant curvature and meandering wavefronts.
DEFF Research Database (Denmark)
Tatu, Aditya Jayant
defined subspace, the N-links bicycle chain space, i.e. the space of curves with equidistant neighboring landmark points. This in itself is a useful shape space for medical image analysis applications. The Histogram of Gradient orientation based features are many in number and are widely used......This thesis deals with two unrelated issues, restricting curve evolution to subspaces and computing image patches in the equivalence class of Histogram of Gradient orientation based features using nonlinear projection methods. Curve evolution is a well known method used in various applications like...... specific requirements like shape priors or a given data model, and due to limitations of the computer, the computed curve evolution forms a path in some finite dimensional subspace of the space of curves. We give methods to restrict the curve evolution to a finite dimensional linear or implicitly defined...
Growth curves in Down syndrome with congenital heart disease
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Caroline D’Azevedo Sica
Full Text Available SUMMARY Introduction: To assess dietary habits, nutritional status and food frequency in children and adolescents with Down syndrome (DS and congenital heart disease (CHD. Additionally, we attempted to compare body mass index (BMI classifications according to the World Health Organization (WHO curves and curves developed for individuals with DS. Method: Cross-sectional study including individuals with DS and CHD treated at a referral center for cardiology, aged 2 to 18 years. Weight, height, BMI, total energy and food frequency were measured. Nutritional status was assessed using BMI for age and gender, using curves for evaluation of patients with DS and those set by the WHO. Results: 68 subjects with DS and CHD were evaluated. Atrioventricular septal defect (AVSD was the most common heart disease (52.9%. There were differences in BMI classification between the curves proposed for patients with DS and those proposed by the WHO. There was an association between consumption of vitamin E and polyunsaturated fatty acids. Conclusion: Results showed that individuals with DS are mostly considered normal weight for age, when evaluated using specific curves for DS. Reviews on specific curves for DS would be the recommended practice for health professionals so as to avoid precipitated diagnosis of overweight and/or obesity in this population.
Income inequality and economic growth-the Kuznets curve revisited
Institute of Scientific and Technical Information of China (English)
YIN Heng; GONG Liutang; ZOU Heng-fu
2006-01-01
In a neoclassical growth framework with a typical political-economy mechanism,this paper reexamines the relationship between the income inequality and economic growth by introducing government spending into the production function and the utility function.It demonstrates that Kuznets' famous inverted-U shape relationship between inequality and economic growth will hold-the growth rate will be first increasing with the income inequality before the growth rate decreases with inequality.
Modeling Pacing Behavior and Test Speededness Using Latent Growth Curve Models
Kahraman, Nilufer; Cuddy, Monica M.; Clauser, Brian E.
2013-01-01
This research explores the usefulness of latent growth curve modeling in the study of pacing behavior and test speededness. Examinee response times from a high-stakes, computerized examination, collected before and after the examination was subjected to a timing change, were analyzed using a series of latent growth curve models to detect…
The Effects of Autocorrelation on the Curve-of-Factors Growth Model
Murphy, Daniel L.; Beretvas, S. Natasha; Pituch, Keenan A.
2011-01-01
This simulation study examined the performance of the curve-of-factors model (COFM) when autocorrelation and growth processes were present in the first-level factor structure. In addition to the standard curve-of factors growth model, 2 new models were examined: one COFM that included a first-order autoregressive autocorrelation parameter, and a…
Comparing non-linear mathematical models to describe growth of different animals
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Jhony Tiago Teleken
2017-02-01
Full Text Available The main objective of this study was to compare the goodness of fit of five non-linear growth models, i.e. Brody, Gompertz, Logistic, Richards and von Bertalanffy in different animals. It also aimed to evaluate the influence of the shape parameter on the growth curve. To accomplish this task, published growth data of 14 different groups of animals were used and four goodness of fit statistics were adopted: coefficient of determination (R2, root mean square error (RMSE, Akaike information criterion (AIC and Bayesian information criterion (BIC. In general, the Richards growth equation provided better fits to experimental data than the other models. However, for some animals, different models exhibited better performance. It was obtained a possible interpretation for the shape parameter, in such a way that can provide useful insights to predict animal growth behavior.
Lu, Yi
2016-01-01
To model students' math growth trajectory, three conventional growth curve models and three growth mixture models are applied to the Early Childhood Longitudinal Study Kindergarten-Fifth grade (ECLS K-5) dataset in this study. The results of conventional growth curve model show gender differences on math IRT scores. When holding socio-economic…
Directory of Open Access Journals (Sweden)
Michael D. Coovert
2017-08-01
Full Text Available Trust plays a central role in the effectiveness of work groups and teams. This is the case for both face-to-face and virtual teams. Yet little is known about the development of trust in virtual teams. We examined cognitive and affective trust and their relationship to team effectiveness as reflected through satisfaction with one’s team and task performance. Latent growth curve analysis reveals both trust types start at a significant level with individual differences in that initial level. Cognitive trust follows a linear growth pattern while affective trust is overall non-linear, but becomes linear once established. Latent change score models are utilized to examine change in trust and also its relationship with satisfaction with the team and team performance. In examining only change in trust and its relationship to satisfaction there appears to be a straightforward influence of trust on satisfaction and satisfaction on trust. However, when incorporated into a bivariate coupling latent change model the dynamics of the relationship are revealed. A similar pattern holds for trust and task performance; however, in the bivariate coupling change model a more parsimonious representation is preferred.
Combining biomarkers linearly and nonlinearly for classification using the area under the ROC curve.
Fong, Youyi; Yin, Shuxin; Huang, Ying
2016-09-20
In biomedical studies, it is often of interest to classify/predict a subject's disease status based on a variety of biomarker measurements. A commonly used classification criterion is based on area under the receiver operating characteristic curve (AUC). Many methods have been proposed to optimize approximated empirical AUC criteria, but there are two limitations to the existing methods. First, most methods are only designed to find the best linear combination of biomarkers, which may not perform well when there is strong nonlinearity in the data. Second, many existing linear combination methods use gradient-based algorithms to find the best marker combination, which often result in suboptimal local solutions. In this paper, we address these two problems by proposing a new kernel-based AUC optimization method called ramp AUC (RAUC). This method approximates the empirical AUC loss function with a ramp function and finds the best combination by a difference of convex functions algorithm. We show that as a linear combination method, RAUC leads to a consistent and asymptotically normal estimator of the linear marker combination when the data are generated from a semiparametric generalized linear model, just as the smoothed AUC method. Through simulation studies and real data examples, we demonstrate that RAUC outperforms smooth AUC in finding the best linear marker combinations, and can successfully capture nonlinear pattern in the data to achieve better classification performance. We illustrate our method with a dataset from a recent HIV vaccine trial. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Equilibrium equations for nonlinear buckling analysis of drill-strings in 3D curved well-bores
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
With the development of drilling technology, the oil/gas well has evolved from its early vertical straight form to the inclined, horizontal, plane curved, or even 3D curved well-bore. Understanding of the buck- ling behavior of a drill-string in a well-bore is crucial for the success of a drilling operation. Therefore, equilibrium equations for analyzing the buckling behavior of a drill-string in a 3D curved well-bore are required. Based on Love’s equilibrium equations for a curved and twisted rod in space, a set of equi- librium equations for the nonlinear buckling analysis of a drill-string in a 3D curved well-bore are de- rived by introducing a radial constraint of the well-bore. The proposed formulae can account for the well curvature and tortuosity. Thus, it can be used to analyze the buckling behaviors of a drill-string constrained in a well-bore and subjected to axial compression, torsion at its upper end, and gravity simultaneously. It is worth noting that the existing equations in the literature for a drill-string in a straight and plane curved well-bore with a constant curvature are a special case of the proposed model. Thus, the present model can provide a theoretical basis for the nonlinear buckling analysis of a drill-string constrained in a 3D curved well-bore.
Equilibrium equations for nonlinear buckling analysis of drill-strings in 3D curved well-bores
Institute of Scientific and Technical Information of China (English)
TAN MeiLan; GAN LiFei
2009-01-01
With the development of drilling technology, the oil/gas well has evolved from its early vertical straight form to the inclined, horizontal, plane curved, or even 3D curved well-bore. Understanding of the buck-ling behavior of a drill-string in a well-bore is crucial for the success of a drilling operation. Therefore, equilibrium equations for analyzing the buckling behavior of a drill-string in a 3D curved well-bore are required. Based on Love's equilibrium equations for a curved and twisted rod in space, s set of equi-librium equations for the nonlinear buckling analysis of a drill-string in a 3D curved well-bore are de-rived by introducing a radial constraint of the well-bore. The proposed formulae can account for the well curvature and tortuosity. Thus, it can be used to analyze the buckling behaviors of a drill-string constrained in a well-bore and subjected to axial compression, torsion at its upper end, and gravity simultaneously. It is worth noting that the existing equations in the literature for a drill-string in a straight and plane curved well-bore with a constant curvature are a special case of the proposed model. Thus, the present model can provide s theoretical basis for the nonlinear buckling analysis of a drill-string constrained in a 3D curved well-bore.
NONLINEAR MODELS FOR DESCRIPTION OF CACAO FRUIT GROWTH WITH ASSUMPTION VIOLATIONS
Directory of Open Access Journals (Sweden)
JOEL AUGUSTO MUNIZ
2017-01-01
Full Text Available Cacao (Theobroma cacao L. is an important fruit in the Brazilian economy, which is mainly cultivated in the southern State of Bahia. The optimal stage for harvesting is a major factor for fruit quality and the knowledge on its growth curves can help, especially in identifying the ideal maturation stage for harvesting. Nonlinear regression models have been widely used for description of growth curves. However, several studies in this subject do not consider the residual analysis, the existence of a possible dependence between longitudinal observations, or the sample variance heterogeneity, compromising the modeling quality. The objective of this work was to compare the fit of nonlinear regression models, considering residual analysis and assumption violations, in the description of the cacao (clone Sial-105 fruit growth. The data evaluated were extracted from Brito and Silva (1983, who conducted the experiment in the Cacao Research Center, Ilheus, State of Bahia. The variables fruit length, diameter and volume as a function of fruit age were studied. The use of weighting and incorporation of residual dependencies was efficient, since the modeling became more consistent, improving the model fit. Considering the first-order autoregressive structure, when needed, leads to significant reduction in the residual standard deviation, making the estimates more reliable. The Logistic model was the most efficient for the description of the cacao fruit growth.
Duc, Nguyen Dinh; Quan, Tran Quoc
2013-11-01
The nonlinear response of buckling and posbuckling of imperfect thin functionally graded doubly curved thin shallow shells resting on elastic foundations and subjected to some mechanical loads is investigated analytically. The elastic moduli of materials, Young's modulus, and Poisson ratio are all graded in the shell thickness direction according to a simple power-law in terms of volume fractions of constituents. All formulations are based on the classical theory of shells with account of geometrical nonlinearity, an initial geometrical imperfection, and a Pasternak-type elastic foundation. By employing the Galerkin method, explicit relations for the load-deflection curves of simply supported doubly curved shallow FGM shells are determined. The effects of material and geometrical properties, foundation stiffness, and imperfection of shells on the buckling and postbuckling loadcarrying capacity of spherical and cylindrical shallow FGM shells are analyzed and discussed.
Curve progression and spinal growth in brace treated idiopathic scoliosis
Tonseth, KA; Veldhuizen, AG; Cool, JC; van Horn, [No Value
2000-01-01
The risk of progression of idiopathic scoliosis is correlated primarily to factors that predict potential remaining skeletal growth. The aim of the current study was to evaluate spinal growth, measured as the length of the scoliotic spine on serial longitudinal radiographs, and its relationship to p
Nonlinear Optical BBO Crystals: Growth, Properties and Applications
Institute of Scientific and Technical Information of China (English)
唐鼎元
2000-01-01
Low temperature phase barium metaborate β-BaB2O4 (BBO) is an important nonlinear optical material. Up to now, the BBO single crystals with large size and good optical quality were grown from Na2O or NaF fluxed solvents by the top-seeded solution growth (TSSG) technique with or without pulling. In order to improve the growth rate and quality of BBO crystals, several new techniques such as continuous feeding, forced stirring and cooling growing crystals etc. have been suggested. Applications of BBO as an excellent nonlinear optical crystal include mainly frequency conversion of various laser radiation, high average power frequency conversion, frequency doubling of ultrashort pulses and broadly tunable optical parametric oscillators (OPO).This paper is a brief review on the growth, properties and applications of BBO crystals.
Crystal growth in fluid flow: Nonlinear response effects
Peng, H. L.; Herlach, D. M.; Voigtmann, Th.
2017-08-01
We investigate crystal-growth kinetics in the presence of strong shear flow in the liquid, using molecular-dynamics simulations of a binary-alloy model. Close to the equilibrium melting point, shear flow always suppresses the growth of the crystal-liquid interface. For lower temperatures, we find that the growth velocity of the crystal depends nonmonotonically on the shear rate. Slow enough flow enhances the crystal growth, due to an increased particle mobility in the liquid. Stronger flow causes a growth regime that is nearly temperature-independent, in striking contrast to what one expects from the thermodynamic and equilibrium kinetic properties of the system, which both depend strongly on temperature. We rationalize these effects of flow on crystal growth as resulting from the nonlinear response of the fluid to strong shearing forces.
Non-linear growth and condensation in multiplex networks
Nicosia, Vincenzo; Latora, Vito; Barthelemy, Marc
2013-01-01
Different types of interactions coexist and coevolve to shape the structure and function of a multiplex network. We propose here a general class of growth models in which the various layers of a multiplex network coevolve through a set of non-linear preferential attachment rules. We show, both numerically and analytically, that by tuning the level of non-linearity these models allow to reproduce either homogeneous or heterogeneous degree distributions, together with positive or negative degree correlations across layers. In particular, we derive the condition for the appearance of a condensed state in which a single node connects to nearly all other nodes of a layer.
On Constructing the Minimal Seed of Turbulence: Nonlinear Transient Growth
Pringle, Chris C T
2010-01-01
Linear transient growth analysis is commonly used to suggest the structure of disturbances which are particularly efficient in triggering transition to turbulence in shear flows. We demonstrate that the addition of nonlinearity to the analysis can substantially change the prediction made in pipe flow from simple 2 dimensional streamwise rolls to a spanwise and cross-stream localised 3 dimensional state. This new nonlinear optimal is demonstrably more efficient in triggering turbulence than the linear optimal indicating that there are better ways to design perturbations to achieve transition.
A Nonlinear Viscous Model for Sn-Whisker Growth
Yang, Fuqian
2016-12-01
Based on the mechanism of the grain boundary fluid flow, a nonlinear viscous model for the growth of Sn-whiskers is proposed. This model consists of two units, one with a stress exponent of one and one with a stress exponent of n -1. By letting one of the constants be zero in the model, the constitutive relationship reduces to a linear flow relation or a power-law relation, representing the flow behavior of various metals. Closed-form solutions for the growth behavior of a whisker are derived, which can be used to predict the whisker growth and the stress evolution.
Directory of Open Access Journals (Sweden)
A.D.V. Garnero
2013-08-01
Full Text Available This work aims to determine the most suitable nonlinear model to describe the growth of female collared peccaries (Pecari tajacu. The monthly records of the weight of 10 captive female collared peccaries over a period of two years in the Brazilian Amazon Region were used. The growth models used were the Von Bertalanffy, Brody, Gompertz and Logistic. The parameters were estimated by using the NLIN procedure from the SAS application. The criteria used to verify the adjustment of the models were: asymptotic standard deviation (ASD; coefficient of determination (R²; average absolute residual deviation (ARD and the asymptotic rate (AR. The Brody model and the Logistic model estimated the highest (19.44kg and the lowest (19.18kg asymptotic weight (A, indicating the lowest (0.0070kg/day and the highest (0.0121kg/day maturation rate (K. These results and the coefficients of phenotypic correlation that varied from -0.75 and -0.47 confirmed the antagonistic nature between these parameters. The Brody model estimated the lower value for ARD, a limiting factor for describing the lowest value for AR through this model. The Brody model showed the best adjustment for AR, although the other models also showed a suitable adjustment to the weight data of said species/gender. Based on the AR obtained in this work, the Brody model is recommended for adjusting the growth curve of the female collared peccaries. Depending on the estimated values, especially for K, this trait can be included in a selection index.
Using the Yield Curve in Forecasting Output Growth and In‡flation
DEFF Research Database (Denmark)
Hillebrand, Eric Tobias; Huang, Huiyu; Lee, Tae-Hwy
Following Diebold and Li (2006), we use the Nelson-Siegel (NS, 1987) yield curve factors. However the NS yield curve factors are not supervised for a specifi…c forecast target in the sense that the same factors are used for forecasting different variables, e.g., output growth or infl‡ation. We...... propose a modifed NS factor model, where the new NS yield curve factors are supervised for a specifi…c variable to forecast. We show it outperforms the conventional (non-supervised) NS factor model in out-of-sample forecasting of monthly US output growth and infl‡ation. The original NS yield factor model...... is to combine information (CI) of predictors and uses factors of predictors (yield curve). The new supervised NS factor model is to combine forecasts (CF) and uses factors of forecasts of output growth or infl‡ation conditional on the yield curve. We formalize the concept of supervision, and demonstrate...
Parent Involvement and Science Achievement: A Latent Growth Curve Analysis
Johnson, Ursula Yvette
2011-01-01
This study examined science achievement growth across elementary and middle school and parent school involvement using the Early Childhood Longitudinal Study-Kindergarten Class of 1998-1999 (ECLS-K). The ECLS-K is a nationally representative kindergarten cohort of students from public and private schools who attended full-day or half-day…
Nonlinear Structured Growth Mixture Models in Mplus and OpenMx
Grimm, Kevin J.; Ram, Nilam; Estabrook, Ryne
2014-01-01
Growth mixture models (GMMs; Muthén & Muthén, 2000; Muthén & Shedden, 1999) are a combination of latent curve models (LCMs) and finite mixture models to examine the existence of latent classes that follow distinct developmental patterns. GMMs are often fit with linear, latent basis, multiphase, or polynomial change models because of their common use, flexibility in modeling many types of change patterns, the availability of statistical programs to fit such models, and the ease of programming. In this paper, we present additional ways of modeling nonlinear change patterns with GMMs. Specifically, we show how LCMs that follow specific nonlinear functions can be extended to examine the presence of multiple latent classes using the Mplus and OpenMx computer programs. These models are fit to longitudinal reading data from the Early Childhood Longitudinal Study-Kindergarten Cohort to illustrate their use. PMID:25419006
Nonlinear Structured Growth Mixture Models in Mplus and OpenMx.
Grimm, Kevin J; Ram, Nilam; Estabrook, Ryne
2010-01-01
Growth mixture models (GMMs; Muthén & Muthén, 2000; Muthén & Shedden, 1999) are a combination of latent curve models (LCMs) and finite mixture models to examine the existence of latent classes that follow distinct developmental patterns. GMMs are often fit with linear, latent basis, multiphase, or polynomial change models because of their common use, flexibility in modeling many types of change patterns, the availability of statistical programs to fit such models, and the ease of programming. In this paper, we present additional ways of modeling nonlinear change patterns with GMMs. Specifically, we show how LCMs that follow specific nonlinear functions can be extended to examine the presence of multiple latent classes using the Mplus and OpenMx computer programs. These models are fit to longitudinal reading data from the Early Childhood Longitudinal Study-Kindergarten Cohort to illustrate their use.
First Versus Second Order Latent Growth Curve Models: Some Insights From Latent State-Trait Theory
Geiser, Christian; Keller, Brian; Lockhart, Ginger
2013-01-01
First order latent growth curve models (FGMs) estimate change based on a single observed variable and are widely used in longitudinal research. Despite significant advantages, second order latent growth curve models (SGMs), which use multiple indicators, are rarely used in practice, and not all aspects of these models are widely understood. In this article, our goal is to contribute to a deeper understanding of theoretical and practical differences between FGMs and SGMs. We define the latent ...
Growth curve and development of the internal calli structure of Eucalyptus camaldulensis Dehn
Directory of Open Access Journals (Sweden)
Evânia Galvão Mendonça
2012-12-01
Full Text Available The objective of this work was to elucidate the growth curve of Eucalyptus camaldulensis Dehn. calli analyzing their anatomical modifications. A sigmoid aspect of the growth curve of the calli fresh matter was observed, with five different phases (lag, exponential, linear, deceleration and decline. In the lag phase, the highest growth percentage 87%, was observed, which reduced during the evaluation period to 17% in the linear phase. As for the anatomical analyses, cellular multiplications was observed during the lag and exponential phases and increase in cell size during the linear phase, promoting the calli volume growth and the establishment of the globular conformation.
A mathematical description of maize leaf area growth using a logistic curve
Directory of Open Access Journals (Sweden)
M. Seidler
2013-12-01
Full Text Available In this paper, an attempt is made to apply the Verhulst-Pearl and the Robertson logistic curves to the description of maize plant growth. The changes with time of the total leaf area were taken as the parameter expressing the growth kinetics. The constant coefficients in the Verhulst-Pearl and Robertson equations were calculated with the help of a logarithmic transformation and the least square method. On this basis, the growth kinetics of the studied maize lines and hybrid were compared. The applicability of logistic curves to the description of completed growth processes was demonstrated as was the fact that Robertson's equation is better suited for mathematical calculations.
Understanding the Scalability of Bayesian Network Inference Using Clique Tree Growth Curves
Mengshoel, Ole J.
2010-01-01
One of the main approaches to performing computation in Bayesian networks (BNs) is clique tree clustering and propagation. The clique tree approach consists of propagation in a clique tree compiled from a Bayesian network, and while it was introduced in the 1980s, there is still a lack of understanding of how clique tree computation time depends on variations in BN size and structure. In this article, we improve this understanding by developing an approach to characterizing clique tree growth as a function of parameters that can be computed in polynomial time from BNs, specifically: (i) the ratio of the number of a BN s non-root nodes to the number of root nodes, and (ii) the expected number of moral edges in their moral graphs. Analytically, we partition the set of cliques in a clique tree into different sets, and introduce a growth curve for the total size of each set. For the special case of bipartite BNs, there are two sets and two growth curves, a mixed clique growth curve and a root clique growth curve. In experiments, where random bipartite BNs generated using the BPART algorithm are studied, we systematically increase the out-degree of the root nodes in bipartite Bayesian networks, by increasing the number of leaf nodes. Surprisingly, root clique growth is well-approximated by Gompertz growth curves, an S-shaped family of curves that has previously been used to describe growth processes in biology, medicine, and neuroscience. We believe that this research improves the understanding of the scaling behavior of clique tree clustering for a certain class of Bayesian networks; presents an aid for trade-off studies of clique tree clustering using growth curves; and ultimately provides a foundation for benchmarking and developing improved BN inference and machine learning algorithms.
Growth curve analysis for plasma profiles using smoothing splines
Energy Technology Data Exchange (ETDEWEB)
Imre, K.
1993-05-01
We are developing a profile analysis code for the statistical estimation of the parametric dependencies of the temperature and density profiles in tokamaks. Our code uses advanced statistical techniques to determine the optimal fit, i.e. the fit which minimized the predictive error. For a forty TFTR Ohmic profile dataset, our preliminary results indicate that the profile shape depends almost exclusively on q[sub a][prime] but that the shape dependencies are not Gaussian. We are now comparing various shape models on the TFTR data. In the first six months, we have completed the core modules of the code, including a B-spline package for variable knot locations, a data-based method to determine the optimal smoothing parameters, self-consistent estimation of the bias errors, and adaptive fitting near the plasma edge. Visualization graphics already include three dimensional surface plots, and discharge by discharge plots of the predicted curves with error bars together with the actual measurements values, and plots of the basis functions with errors.
Hossein-Zadeh, Navid Ghavi
2016-08-01
The aim of this study was to compare seven non-linear mathematical models (Brody, Wood, Dhanoa, Sikka, Nelder, Rook and Dijkstra) to examine their efficiency in describing the lactation curves for milk fat to protein ratio (FPR) in Iranian buffaloes. Data were 43 818 test-day records for FPR from the first three lactations of Iranian buffaloes which were collected on 523 dairy herds in the period from 1996 to 2012 by the Animal Breeding Center of Iran. Each model was fitted to monthly FPR records of buffaloes using the non-linear mixed model procedure (PROC NLMIXED) in SAS and the parameters were estimated. The models were tested for goodness of fit using Akaike's information criterion (AIC), Bayesian information criterion (BIC) and log maximum likelihood (-2 Log L). The Nelder and Sikka mixed models provided the best fit of lactation curve for FPR in the first and second lactations of Iranian buffaloes, respectively. However, Wood, Dhanoa and Sikka mixed models provided the best fit of lactation curve for FPR in the third parity buffaloes. Evaluation of first, second and third lactation features showed that all models, except for Dijkstra model in the third lactation, under-predicted test time at which daily FPR was minimum. On the other hand, minimum FPR was over-predicted by all equations. Evaluation of the different models used in this study indicated that non-linear mixed models were sufficient for fitting test-day FPR records of Iranian buffaloes.
Nonlinear time series analysis of the light curves from the black hole system GRS1915+105
Institute of Scientific and Technical Information of China (English)
K.P Harikrishnan; Ranjeev Misra; G.Ambika
2011-01-01
GRS 1915+105 is a prominent black hole system exhibiting variability over a wide range of time scales and its observed light curves have been classified into 12 temporal states. Here we undertake a complete analysis of these light curves from all the states using various quantifiers from nonlinear time series analysis, such as the correlation dimension (D2), the correlation entropy (K2), singular value decomposition (SVD) and the multifractal spectrum (f(α) spectrum). An important aspect of our analysis is that, for estimating these quantifiers, we use algorithmic schemes which we have recently proposed and successfully tested on synthetic as well as practical time series from various fields. Though the schemes are based on the conventional delay embedding technique, they are automated so that the above quantitative measures can be computed using conditions prescribed by the algorithm and without any intermediate subjective analysis. We show that nearly half of the 12 temporal states exhibit deviation from randomness and their complex temporal behavior could be approximated by a few (three or four) coupled ordinary nonlinear differential equations. These results could be important for a better understanding of the processes that generate the light curves and hence for modeling the temporal behavior of such complex systems.To our knowledge, this is the first complete analysis of an astrophysical object (let alone a black hole system) using various techniques from nonlinear dynamics.
Directory of Open Access Journals (Sweden)
Qihua Tan
2011-01-01
Full Text Available Identifying the various gene expression response patterns is a challenging issue in expression microarray time-course experiments. Due to heterogeneity in the regulatory reaction among thousands of genes tested, it is impossible to manually characterize a parametric form for each of the time-course pattern in a gene by gene manner. We introduce a growth curve model with fractional polynomials to automatically capture the various time-dependent expression patterns and meanwhile efficiently handle missing values due to incomplete observations. For each gene, our procedure compares the performances among fractional polynomial models with power terms from a set of fixed values that offer a wide range of curve shapes and suggests a best fitting model. After a limited simulation study, the model has been applied to our human in vivo irritated epidermis data with missing observations to investigate time-dependent transcriptional responses to a chemical irritant. Our method was able to identify the various nonlinear time-course expression trajectories. The integration of growth curves with fractional polynomials provides a flexible way to model different time-course patterns together with model selection and significant gene identification strategies that can be applied in microarray-based time-course gene expression experiments with missing observations.
Traditional and alternative nonlinear models for estimating the growth of Morada Nova sheep
Directory of Open Access Journals (Sweden)
Laaina de Andrade Souza
2013-09-01
Full Text Available In the present study, alternative and traditional nonlinear models to describe growth curves of Morada Nova sheep reared in the state of Bahia, Brazil, were applied. The nonlinear models were: Schnute, Mitscherlich, Gompertz, Logistic, Meloun I Meloun II, III Meloun, Gamito and Meloun IV. The model adjustment was evaluated by using: Adjusted Coefficient of Determination (R²aj, Akaike Information Criterion (AIC, Bayesian Information Criterion (BIC, Mean Squared Error of Prediction (MEP and Coefficient of Determination of Prediction (R²p. The selection of the best model was based on cluster analysis, using the evaluators as variables. Six out of the nine tested models converged, while Meloun I and Meloun IV were equally effective in explaining animal growth, without significant influence of sex or type of parturition over the curve parameters. The models Meloun I and IV have the best adjustment and reveal a remarkable reduction of weight gain after 150 days of age, which indicates special attention should be given to feeding at this stage.
Body temperatures in dinosaurs: what can growth curves tell us?
Griebeler, Eva Maria
2013-01-01
To estimate the body temperature (BT) of seven dinosaurs Gillooly, Alleen, and Charnov (2006) used an equation that predicts BT from the body mass and maximum growth rate (MGR) with the latter preserved in ontogenetic growth trajectories (BT-equation). The results of these authors evidence inertial homeothermy in Dinosauria and suggest that, due to overheating, the maximum body size in Dinosauria was ultimately limited by BT. In this paper, I revisit this hypothesis of Gillooly, Alleen, and Charnov (2006). I first studied whether BTs derived from the BT-equation of today's crocodiles, birds and mammals are consistent with core temperatures of animals. Second, I applied the BT-equation to a larger number of dinosaurs than Gillooly, Alleen, and Charnov (2006) did. In particular, I estimated BT of Archaeopteryx (from two MGRs), ornithischians (two), theropods (three), prosauropods (three), and sauropods (nine). For extant species, the BT value estimated from the BT-equation was a poor estimate of an animal's core temperature. For birds, BT was always strongly overestimated and for crocodiles underestimated; for mammals the accuracy of BT was moderate. I argue that taxon-specific differences in the scaling of MGR (intercept and exponent of the regression line, log-log-transformed) and in the parameterization of the Arrhenius model both used in the BT-equation as well as ecological and evolutionary adaptations of species cause these inaccuracies. Irrespective of the found inaccuracy of BTs estimated from the BT-equation and contrary to the results of Gillooly, Alleen, and Charnov (2006) I found no increase in BT with increasing body mass across all dinosaurs (Sauropodomorpha, Sauropoda) studied. This observation questions that, due to overheating, the maximum size in Dinosauria was ultimately limited by BT. However, the general high inaccuracy of dinosaurian BTs derived from the BT-equation makes a reliable test of whether body size in dinosaurs was ultimately limited
Body temperatures in dinosaurs: what can growth curves tell us?
Directory of Open Access Journals (Sweden)
Eva Maria Griebeler
Full Text Available To estimate the body temperature (BT of seven dinosaurs Gillooly, Alleen, and Charnov (2006 used an equation that predicts BT from the body mass and maximum growth rate (MGR with the latter preserved in ontogenetic growth trajectories (BT-equation. The results of these authors evidence inertial homeothermy in Dinosauria and suggest that, due to overheating, the maximum body size in Dinosauria was ultimately limited by BT. In this paper, I revisit this hypothesis of Gillooly, Alleen, and Charnov (2006. I first studied whether BTs derived from the BT-equation of today's crocodiles, birds and mammals are consistent with core temperatures of animals. Second, I applied the BT-equation to a larger number of dinosaurs than Gillooly, Alleen, and Charnov (2006 did. In particular, I estimated BT of Archaeopteryx (from two MGRs, ornithischians (two, theropods (three, prosauropods (three, and sauropods (nine. For extant species, the BT value estimated from the BT-equation was a poor estimate of an animal's core temperature. For birds, BT was always strongly overestimated and for crocodiles underestimated; for mammals the accuracy of BT was moderate. I argue that taxon-specific differences in the scaling of MGR (intercept and exponent of the regression line, log-log-transformed and in the parameterization of the Arrhenius model both used in the BT-equation as well as ecological and evolutionary adaptations of species cause these inaccuracies. Irrespective of the found inaccuracy of BTs estimated from the BT-equation and contrary to the results of Gillooly, Alleen, and Charnov (2006 I found no increase in BT with increasing body mass across all dinosaurs (Sauropodomorpha, Sauropoda studied. This observation questions that, due to overheating, the maximum size in Dinosauria was ultimately limited by BT. However, the general high inaccuracy of dinosaurian BTs derived from the BT-equation makes a reliable test of whether body size in dinosaurs was ultimately
Teaching the Microbial Growth Curve Concept Using Microalgal Cultures and Flow Cytometry
Forget, Nathalie; Belzile, Claude; Rioux, Pierre; Nozais, Christian
2010-01-01
The microbial growth curve is widely studied within microbiology classes and bacteria are usually the microbial model used. Here, we describe a novel laboratory protocol involving flow cytometry to assess the growth dynamics of the unicellular microalgae "Isochrysis galbana." The algal model represents an appropriate alternative to…
Shin, Tacksoo; Davison, Mark L.; Long, Jeffrey D.; Chan, Chi-Keung; Heistad, David
2013-01-01
Using four-wave longitudinal reading and mathematics data (4th to 7th grades) from a large urban school district, growth curve modeling was used as a tool for examining three research questions: Are achievement gaps closing in reading and mathematics? What are the associations between prior-achievement and growth across the reading and mathematics…
Teaching the Microbial Growth Curve Concept Using Microalgal Cultures and Flow Cytometry
Forget, Nathalie; Belzile, Claude; Rioux, Pierre; Nozais, Christian
2010-01-01
The microbial growth curve is widely studied within microbiology classes and bacteria are usually the microbial model used. Here, we describe a novel laboratory protocol involving flow cytometry to assess the growth dynamics of the unicellular microalgae "Isochrysis galbana." The algal model represents an appropriate alternative to bacteria…
Johnson, Ursula Y.; Hull, Darrell M.
2014-01-01
The authors examined science achievement growth at Grades 3, 5, and 8 and parent school involvement at the same time points using the Early Childhood Longitudinal Study-Kindergarten Class of 1998-1999. Data were analyzed using cross-classified multilevel latent growth curve modeling with time invariant and varying covariates. School-based…
Growth Curve and Structural Equation Modeling : Topics from the Indian Statistical Institute
2015-01-01
This book describes some recent trends in GCM research on different subject areas, both theoretical and applied. This includes tools and possibilities for further work through new techniques and modification of existing ones. A growth curve is an empirical model of the evolution of a quantity over time. Growth curves in longitudinal studies are used in disciplines including biology, statistics, population studies, economics, biological sciences, sociology, nano-biotechnology, and fluid mechanics. The volume includes original studies, theoretical findings and case studies from a wide range of applied work. This volume builds on presentations from a GCM workshop held at the Indian Statistical Institute, Giridih, January 18-19, 2014. This book follows the volume Advances in Growth Curve Models, published by Springer in 2013. The results have meaningful application in health care, prediction of crop yield, child nutrition, poverty measurements, estimation of growth rate, and other research areas.
Analysis of the nonlinear dynamics of a 2-axle freight wagon in curves
DEFF Research Database (Denmark)
Di Gialleonardo, Egidio; Bruni, Stefano; True, Hans
2014-01-01
and bifurcations are identified for some particular values of the curve radius. For the single car case, it is shown that depending on the curve radius and the vehicle speed the carbody may experience severe periodic oscillations at speeds lying in the operating range of the vehicle. For the car-assembly case...
Non-linear plasma wake growth of electron holes
Hutchinson, I. H.; Haakonsen, C. B.; Zhou, C.
2015-03-01
An object's wake in a plasma with small Debye length that drifts across the magnetic field is subject to electrostatic electron instabilities. Such situations include, for example, the moon in the solar wind and probes in magnetized laboratory plasmas. The instability drive mechanism can equivalently be considered drift down the potential-energy gradient or drift up the density-gradient. The gradients arise because the plasma wake has a region of depressed density and electrostatic potential into which ions are attracted along the field. The non-linear consequences of the instability are analysed in this paper. At physical ratios of electron to ion mass, neither linear nor quasilinear treatment can explain the observation of large-amplitude perturbations that disrupt the ion streams well before they become ion-ion unstable. We show here, however, that electron holes, once formed, continue to grow, driven by the drift mechanism, and if they remain in the wake may reach a maximum non-linearly stable size, beyond which their uncontrolled growth disrupts the ions. The hole growth calculations provide a quantitative prediction of hole profile and size evolution. Hole growth appears to explain the observations of recent particle-in-cell simulations.
Nonlinear dynamics for charges particle beams with a curved axis in the matrix - recursive model
Energy Technology Data Exchange (ETDEWEB)
Dymnikov, A.D. [University of St Petersburg, (Russian Federation). Institute of Computational Mathematics and Control Process
1993-12-31
In this paper a new matrix and recursive approach has been outlined for treating nonlinear optics of charged particle beams. This approach is a new analytical and computational tool for designers of optimal beam control systems. 9 refs.
Curvas de crescimento na produção animal Growth curves in animal production
Directory of Open Access Journals (Sweden)
Alfredo Ribeiro de Freitas
2005-06-01
Full Text Available Foram discutidas as propriedades de sete modelos não-lineares, considerando-se o ajuste de curvas de crescimento na produção animal. Os modelos utilizados: Brody, Richards, Von Bertalanffy e duas alternativas de Gompertz e de Logístico foram ajustados, pelo método de Gauss Newton por meio do procedimento NLIN do SAS, a dados peso-idade de oito espécies: camarão-d'água-doce, rã-pimenta, coelho, frango, ovino, caprino, suíno e bovino. Considerando-se os critérios como: convergência ou não, coeficiente de determinação e interpretabilidade biológica dos parâmetros, concluiu-se que: a o modelo Logístico y= A/(1 + e-ktm estimou o peso em todas as espécies animais, enquanto o de Von Bertalanffy apenas não foi adequado para camarão; b os dois modelos Gompertz foram adequados para camarão, rã, frango, suíno e bovino; c em cada espécie, pelo menos dois dos sete modelos mostraram-se adequados para estimar o crescimento corporal das espécies animais estudadas, pois os coeficientes de determinação foram superiores a 92,0%.The properties of seven nonlinear models were discussed concerning its applications in the fitting of growth curves in animal production. The models used: Brody, Richards, Von Bertalanffy and two alternatives of Gompertz and Logistic models, were fitted by Gauss Newton method to weight-age data from eight animal species: freshwater prawn Macrobrachium rosenbergi, pepper frog, rabbit, poultry, sheep, goat, swine and cattle. Considering results of the fitted models such as convergence or not, coefficient of determination and biological interpretation of parameters, it was concluded that: a the Logisticmethod y = A/(1 + e-ktm estimated body weight in all species, while the Von Bertalanffy model was not adequate only for freshwater prawn Macrobrachium rosenbergi; b both Gompertz models were adequate for freshwater prawn Macrobrachium rosenbergi, pepper frog, poultry, swine and cattle; c for each specie, at least two
VOID GROWTH AND CAVITATION IN NONLINEAR VISCOELASTIC SOLIDS
Institute of Scientific and Technical Information of China (English)
张赟; 黄筑平
2003-01-01
This paper discusses the growth of a pre-existing void in a nonlinear viscoelastic material subjected to remote hydrostatic tensions with different loading rates. The constitutive relation of this viscoelastic material is the one recently proposed by the present authors, which may be considered as a generalization of the non-Gaussian statistical theory in rubber elasticity. As the first order approximation, the above constitutive relation can be reduced to the "neo-Hookean" type viscoelastic one.Investigations of the influences of the material viscosity and the loading rate on the void growth, or on the cavitation are carried out. It is found that: (1) for generalized "inverse Langevin approximation"nonlinear viscoelastic materials, the cavitation limit does not exist, but there is a certain (remote)stress level at which the void will grow rapidly; (2) for generalized "Gaussian statistics" (neo-Hookean type) viscoelastic materials, the cavitation limit exists, and is an increasing function of the loading rate.The present discussions may be of importance in understanding the material failure process under high triaxial stress.
Symphysis-fundal height curve in the diagnosis of fetal growth deviations
Directory of Open Access Journals (Sweden)
Djacyr Magna Cabral Freire
2010-12-01
Full Text Available OBJECTIVE: To validate a new symphysis-fundal curve for screening fetal growth deviations and to compare its performance with the standard curve adopted by the Brazilian Ministry of Health. METHODS: Observational study including a total of 753 low-risk pregnant women with gestational age above 27 weeks between March to October 2006 in the city of João Pessoa, Northeastern Brazil. Symphisys-fundal was measured using a standard technique recommended by the Brazilian Ministry of Health. Estimated fetal weight assessed through ultrasound using the Brazilian fetal weight chart for gestational age was the gold standard. A subsample of 122 women with neonatal weight measurements was taken up to seven days after estimated fetal weight measurements and symphisys-fundal classification was compared with Lubchenco growth reference curve as gold standard. Sensitivity, specificity, positive and negative predictive values were calculated. The McNemar χ2 test was used for comparing sensitivity of both symphisys-fundal curves studied. RESULTS: The sensitivity of the new curve for detecting small for gestational age fetuses was 51.6% while that of the Brazilian Ministry of Health reference curve was significantly lower (12.5%. In the subsample using neonatal weight as gold standard, the sensitivity of the new reference curve was 85.7% while that of the Brazilian Ministry of Health was 42.9% for detecting small for gestational age. CONCLUSIONS: The diagnostic performance of the new curve for detecting small for gestational age fetuses was significantly higher than that of the Brazilian Ministry of Health reference curve.
Energy Technology Data Exchange (ETDEWEB)
Abbas, Z.; Naveed, M., E-mail: rana.m.naveed@gmail.com [Department of Mathematics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Sajid, M. [Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)
2015-10-15
In this paper, effects of Hall currents and nonlinear radiative heat transfer in a viscous fluid passing through a semi-porous curved channel coiled in a circle of radius R are analyzed. A curvilinear coordinate system is used to develop the mathematical model of the considered problem in the form partial differential equations. Similarity solutions of the governing boundary value problems are obtained numerically using shooting method. The results are also validated with the well-known finite difference technique known as the Keller-Box method. The analysis of the involved pertinent parameters on the velocity and temperature distributions is presented through graphs and tables.
Supplementary Material for: Growth curve registration for evaluating salinity tolerance in barley
Meng, Rui
2017-01-01
Abstract Background Smarthouses capable of non-destructive, high-throughput plant phenotyping collect large amounts of data that can be used to understand plant growth and productivity in extreme environments. The challenge is to apply the statistical tool that best analyzes the data to study plant traits, such as salinity tolerance, or plant-growth-related traits. Results We derive family-wise salinity sensitivity (FSS) growth curves and use registration techniques to summarize growth patterns of HEB-25 barley families and the commercial variety, Navigator. We account for the spatial variation in smarthouse microclimates and in temporal variation across phenotyping runs using a functional ANOVA model to derive corrected FSS curves. From FSS, we derive corrected values for family-wise salinity tolerance, which are strongly negatively correlated with Na but not significantly with K, indicating that Na content is an important factor affecting salinity tolerance in these families, at least for plants of this age and grown in these conditions. Conclusions Our family-wise methodology is suitable for analyzing the growth curves of a large number of plants from multiple families. The corrected curves accurately account for the spatial and temporal variations among plants that are inherent to high-throughput experiments.
Microbial growth curves: what the models tell us and what they cannot.
Peleg, Micha; Corradini, Maria G
2011-12-01
Most of the models of microbial growth in food are Empirical algebraic, of which the Gompertz model is the most notable, Rate equations, mostly variants of the Verhulst's logistic model, or Population Dynamics models, which can be deterministic and continuous or stochastic and discrete. The models of the first two kinds only address net growth and hence cannot account for cell mortality that can occur at any phase of the growth. Almost invariably, several alternative models of all three types can describe the same set of experimental growth data. This lack of uniqueness is by itself a reason to question any mechanistic interpretation of growth parameters obtained by curve fitting alone. As argued, all the variants of the Verhulst's model, including the Baranyi-Roberts model, are empirical phenomenological models in a rate equation form. None provides any mechanistic insight or has inherent advantage over the others. In principle, models of all three kinds can predict non-isothermal growth patterns from isothermal data. Thus a modeler should choose the simplest and most convenient model for this purpose. There is no reason to assume that the dependence of the "maximum specific growth rate" on temperature, pH, water activity, or other factors follows the original or modified versions of the Arrhenius model, as the success of Ratkowsky's square root model testifies. Most sigmoid isothermal growth curves require three adjustable parameters for their mathematical description and growth curves showing a peak at least four. Although frequently observed, there is no theoretical reason that these growth parameters should always rise and fall in unison in response to changes in external conditions. Thus quantifying the effect of an environmental factor on microbial growth require that all the growth parameters are addressed, not just the "maximum specific growth rate." Different methods to determine the "lag time" often yield different values, demonstrating that it is a
Nonlinear growth dynamics and the origin of fluctuating asymmetry
Emlen, J.M.; Freeman, D.C.; Graham, J.H.
1993-01-01
The nonlinear, complex nature of biosynthesis magnifies the impacts of small, random perturbations on organism growth, leading to distortions in adaptive allometries and, in particular, to fluctuating asymmetry. These distortions can be partly checked by cell-cell and inter-body part feedback during growth and development, though the latter mechanism also may lead to complex patterns in right-left asymmetry. Stress can be expected to increase the degree to which random growth perturbations are magnified and may also result in disruption of the check mechanisms, thus exaggerating fluctuating asymmetry.The processes described not only provide one explanation for the existence of fluctuating asymmetry and its augmentation under stress, but suggest additional effects of stress as well. Specifically, stress is predicted to lead to decreased fractal dimension of bone sutures and branching structures in animals, and in increased dimension of growth trace patterns such as those found in mollusc shells and fish otoliths and scales.A basic yet broad primer on fractals and chaos is provided as background for the theoretical development in this manuscript.
Non-linear optical titanyl arsenates: Crystal growth and properties
Nordborg, Jenni Eva Louise
Crystals are appreciated not only for their appearance, but also for their unique physical properties which are utilized by the photonic industry in appliances that we come across every day. An important part of enabling the technical use of optical devices is the manufacture of crystals. This dissertation deals with a specific group of materials called the potassium titanyl phosphate (KIP) family, known for their non-linear optical and ferroelectric properties. The isomorphs vary in their linear optical and dielectric properties, which can be tuned to optimize device performance by forming solid solutions of the different materials. Titanyl arsenates have a wide range of near-infrared transmission which makes them useful for tunable infrared lasers. The isomorphs examined in the present work were primarily RbTiOASO4 (RTA) and CsTiOAsO4 (CTA) together with the mixtures RbxCs 1-xTiOAsO4 (RCTA). Large-scale crystals were grown by top seeding solution growth utilizing a three-zone furnace with excellent temperature control. Sufficiently slow cooling and constant upward lifting produced crystals with large volumes useable for technical applications. Optical quality RTA crystals up to 10 x 12 x 20 mm were grown. The greater difficulty in obtaining good crystals of CTA led to the use of mixed RCTA materials. The mixing of rubidium and cesium in RCTA is more favorable to crystal growth than the single components in pure RTA and CTA. Mixed crystals are rubidium-enriched and contain only 20-30% of the cesium concentration in the flux. The cesium atoms show a preference for the larger cation site. The network structure is very little affected by the cation substitution; consequently, the non-linear optical properties of the Rb-rich isomorphic mixtures of RTA and CTA can be expected to remain intact. Crystallographic methods utilizing conventional X-ray tubes, synchrotron radiation and neutron diffraction have been employed to investigate the properties of the atomic
Transcriptome analysis of genetic mechanism of growth curve inflection point using a pig model
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Linyuan Shen
2015-12-01
Full Text Available Animal growth curves play an important role for animal breeders to optimize feeding and management strategies (De Lange et al., 2001 [1]; Brossard et al., 2009 [2]; Strathe et al., 2010 [3]. However, the genetic mechanism of the phenotypic difference between the inflection point and noninflection points of the growth curve remains unclear. Here, we report the differentially expressed gene pattern in pig longissimus dorsi among three typical time points of the growth curve, inflection point (IP, before inflection point (BIP and after inflection point (AIP. The whole genome RNA-seq data was deposited at GenBank under the accession number PRJNA2284587. The RNA-seq libraries generated 117 million reads of 5.89 gigabases in length. Totals of 21,331, 20,996 and 20,139 expressed transcripts were identified in IP, UIP and AIP, respectively. Furthermore, we identified 757 differentially expressed genes (DEGs between IP and UIP, and 271 DEGs between AIP and IP. Function enrichment analysis of DEGs found that the highly expressed genes in IP were mainly enriched in energy metabolism, global transcriptional activity and bone development intensity. This study contributes to reveal the genetic mechanism of growth curve inflection point.
Ignoring Individual Differences in Times of Assessment in Growth Curve Modeling
Coulombe, Patrick; Selig, James P.; Delaney, Harold D.
2016-01-01
Researchers often collect longitudinal data to model change over time in a phenomenon of interest. Inevitably, there will be some variation across individuals in specific time intervals between assessments. In this simulation study of growth curve modeling, we investigate how ignoring individual differences in time points when modeling change over…
Wang, Chee Keng John; Pyun, Do Young; Liu, Woon Chia; Lim, Boon San Coral; Li, Fuzhong
2013-01-01
Using a multilevel latent growth curve modeling (LGCM) approach, this study examined longitudinal change in levels of physical fitness performance over time (i.e. four years) in young adolescents aged from 12-13 years. The sample consisted of 6622 students from 138 secondary schools in Singapore. Initial analyses found between-school variation on…
Klein, Daniel; Zezula, Ivan
The extended growth curve model is discussed in this paper. There are two versions of the model studied in the literature, which differ in the way how the column spaces of the design matrices are nested. The nesting is applied either to the between-individual or to the within-individual design
Wang, Chee Keng John; Pyun, Do Young; Liu, Woon Chia; Lim, Boon San Coral; Li, Fuzhong
2013-01-01
Using a multilevel latent growth curve modeling (LGCM) approach, this study examined longitudinal change in levels of physical fitness performance over time (i.e. four years) in young adolescents aged from 12-13 years. The sample consisted of 6622 students from 138 secondary schools in Singapore. Initial analyses found between-school variation on…
Prediction of Future Observations in Polynomial Growth Curve Models. Part 1.
1983-03-01
UNIT NUMBERS University of Pittsburgh, Ninth Floor, PE6llO2F; 2304/A5 Schenley Hall, Pittsburgh PA 15260 It CONTROLLING OFFICE NAME AND ADDRESS 12...8217. DSIM Enitvd, ’ SR-TR. 8 3 0491 PREDICTION OF FUTURE OBSERVATIONS IN POLYNOMIAL GROWTH CURVE MODELS PART - 1 C. Radhakrishna Rao University of Pittsburgh
Schaling, E.
1998-01-01
We extend the Svensson (1997a) inflation forecast targeting framework with a convex Phillips curve. We derive an asymmetric target rule, that implies a higher level of nominal interest rates than the Svensson (1997a) forward looking version of the reaction function popularised by Taylor (1993).
Schaling, E.
1998-01-01
We extend the Svensson (1997a) inflation forecast targeting framework with a convex Phillips curve. We derive an asymmetric target rule, that implies a higher level of nominal interest rates than the Svensson (1997a) forward looking version of the reaction function popularised by Taylor (1993). Exte
Modeling of non-linear CHP efficiency curves in distributed energy systems
DEFF Research Database (Denmark)
Milan, Christian; Stadler, Michael; Cardoso, Gonçalo
2015-01-01
Distributed energy resources gain an increased importance in commercial and industrial building design. Combined heat and power (CHP) units are considered as one of the key technologies for cost and emission reduction in buildings. In order to make optimal decisions on investment and operation...... for these technologies, detailed system models are needed. These models are often formulated as linear programming problems to keep computational costs and complexity in a reasonable range. However, CHP systems involve variations of the efficiency for large nameplate capacity ranges and in case of part load operation......, which can be even of non-linear nature. Since considering these characteristics would turn the models into non-linear problems, in most cases only constant efficiencies are assumed. This paper proposes possible solutions to address this issue. For a mixed integer linear programming problem two...
Bi-Hamiltonian Structure of a Third-Order Nonlinear Evolution Equation on Plane Curve Motions
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In the present paper, we identify the integrability of the third-order nonlinear evolution equation ut = (1/2)((uxx + u)-2)x in a Hamiltonian viewpoint. We prove that the recursion operator obtained by S. Yu. Sakovich is hereditary, and then deduce a bi-Hamiltonian structure of the equation by using some decomposition of the hereditary operator. A hierarchy associated to the equation is also shown.
Nonlinear growth of electron holes in cross-field wakes
Hutchinson, Ian; Haakonsen, C. B.; Zhou, C.
2015-11-01
Cross-field plasma flow past an obstacle is key to the physics underlying Mach-probes, space-craft charging, and the wakes of non-magnetic bodies: the solar-wind wake of the moon is a typical example. We report associated new nonlinear instability mechanisms. Ions are accelerated along the B-field into the wake, forming two beams, but they are not initially unstable to ion two-stream instabilities. Electron Langmuir waves become unstable much earlier because of an electron velocity-distribution distortion called the ``dimple''. The magnetic field, perpendicular to the flow, defines the 1-D direction of particle dynamics. In high-fidelity PIC simulations at realistic mass ratio, small electron holes--non-linearly self-binding electron density deficits--are spawned by the dimple in fe (v) near the phase-space separatrix. Most holes accelerate rapidly out of the wake, along B. However, some remain at very low speed, and grow until they are large enough to disrupt the two ion-streams, well before the ions are themselves linearly unstable. This non-linear hole growth is caused by the same mechanism that causes the dimple: cross-field drift from a lower to a higher density. Related mechanisms cause plasma near magnetized Langmuir probes to be unsteady. Partially supported by the NSF/DOE Basic Plasma Science Partnership grant DE-SC0010491.
Fully localised nonlinear energy growth optimals in pipe flow
Pringle, Chris C T; Kerswell, Rich R
2014-01-01
A new, fully-localised, energy growth optimal is found over large times and in long pipe domains at a given mass flow rate. This optimal emerges at a threshold disturbance energy below which a nonlinear version of the known (streamwise-independent) linear optimal (Schmid \\& Henningson 1994) is selected, and appears to remain the optimal up until the critical energy at which transition is triggered. The form of this optimal is similar to that found in short pipes (Pringle et al.\\ 2012) albeit now with full localisation in the streamwise direction. This fully-localised optimal perturbation represents the best approximation yet of the {\\em minimal seed} (the smallest perturbation capable of triggering a turbulent episode) for `real' (laboratory) pipe flows.
A new computational tool for the phenomenological analysis of multipassage tumor growth curves.
Directory of Open Access Journals (Sweden)
Antonio S Gliozzi
Full Text Available Multipassage experiments are performed by subcutaneous implantation in lab animals (usually mice of a small number of cells from selected human lines. Tumor cells are then passaged from one mouse to another by harvesting them from a growing tumor and implanting them into other healthy animals. This procedure may be extremely useful to investigate the various mechanisms involved in the long term evolution of tumoral growth. It has been observed by several researchers that, contrary to what happens in in vitro experiments, there is a significant growth acceleration at each new passage. This result is explained by a new method of analysis, based on the Phenomenological Universalities approach. It is found that, by means of a simple rescaling of time, it is possible to collapse all the growth curves, corresponding to the successive passages, into a single curve, belonging to the Universality Class U2. Possible applications are proposed and the need of further experimental evidence is discussed.
Directory of Open Access Journals (Sweden)
Lia Budimulyati Salman
2015-05-01
Full Text Available The growth curve is a reflection of the ability of an individual or population to actualize themselves aswell as the size will be the development of the parts of the body until it reaches the maximum size (adulton the existing environmental conditions. The main goal of this study is to determine the growth curvemodel of Friesian Holstein cattle from birth until ready to mate based on birth rates with Logistic model,Gompertz, and von Bertalanffy. The data was used in this study is the result of the weighing of dairy cowsbody weight of female Friesian Holstein as many as 335 head number collected by PT Taurus Dairy FarmSukabumi from 2001to 2011, which have complete data from birth until first mating with a birth rate thatis different from the birth of the one to five. The data used in the analysis of growth curves using three nonlineargrowth curve model i.e. Logistic models, Gompertz, and Von Bertalanffy. The results obtainedindicate that the growth curve model shave different levels of accuracy, depending on the environment andage or duration of observation, the longer observed to mature weight (A, the age of puberty, and pubertygreater weight. The Conclusion of this study is a model of Logistic close to field conditions. Morover thehigher the birth rate will be heavier birth weight and adult weight. These three non-linear mathematicalmodel used in this study has a high degree of accuracy.
A growth model for primary cancer (II). New rules, progress curves and morphology transitions
Jr, S. C. Ferreira; Martins, M. L.; Vilela, M. J.
1999-10-01
In the present paper we extend the analysis of another model recently proposed to simulate the growth of carcinoma “in situ”, which includes cell proliferation, motility and death, as well as chemotactic interactions among cells. The tumour patterns generated by two distinct growth rules are characterised by its gyration radius, surface roughness, total number of cancer cells, and number of cells on tumour periphery. Our results indicate that very distinct morphological patterns follow Gompertz growth curves and their gyration radii increase linearly in time and scale, in the asymptotic limit, as a square root of the total number of tumour cells. In contrast, these distinct tumour patterns exhibit different scaling laws for their surfaces. Thus, some biological features of malignant behaviour seem to influence particularly the structure of the tumour border, while its gyration radius and progress curve are described by more robust functions. Finally, for both rules used, morphology transitions as well as a transient behaviour up to the onset of the phase of rapid growth in the Gompertz curves are observed.
Hyánková, L; Novotná, B; Darras, V M
2008-03-01
1. Changes in the relative weights of carcase, abdominal fat, breast and leg muscles, and plasma thyroid hormone concentrations occurring during the first 6 weeks of postnatal growth were analysed in males of HG and LG lines divergently selected for high and low relative body weight (BW) gain between 11 and 28 d of age, respectively, and constant adult BW. 2. The second week of postnatal life was a critical age at which the HG males exhibited a relatively faster growth in comparison to their LG counterparts and permanently exceeded LG males in the percentage by weight of carcase, breast and leg muscle. A higher production of muscle tissues was associated with lower accumulation of abdominal fat before sexual maturity. 3. In general, the plasma T(3) level of HG quail exceeded that of LG quail. Nevertheless, significant differences were found only at 14, 21 and 28 d of age, that is, in the period during which the highest inter-line differences in relative growth rate were noted. Also the T(3)/T(4) ratio followed a similar trend while plasma T(4) level showed no clear and consistent inter-line differences. 4. The results suggest that the selection for the shape of the growth curve, like the selection for body fat, modifies the carcase quality owing to shortening/prolongation of the acceleration growth phase. Individuals with a short acceleration phase of the growth curve are characterised by low carcase quality during the fattening period.
Che, T D; Wang, C D; Jin, L; Wei, M; Wu, K; Zhang, Y H; Zhang, H M; Li, D S
2015-03-27
Giant panda cubs have a low survival rate during the newborn and early growth stages. However, the growth and developmental parameters of giant panda cubs during the early lactation stage (from birth to 6 months) are not well known. We examined the growth and development of giant panda cubs by the Chapman growth curve model and estimated the heritability of the maximum growth rate at the early lactation stage. We found that 83 giant panda cubs reached their maximum growth rate at approximately 75-120 days after birth. The body weight of cubs at 75 days was 4285.99 g. Furthermore, we estimated that the heritability of the maximum growth rate was moderate (h(2) = 0.38). Our study describes the growth and development of giant panda cubs at the early lactation stage and provides valuable growth benchmarks. We anticipate that our results will be a starting point for more detailed research on increasing the survival rate of giant panda cubs. Feeding programs for giant panda cubs need further improvement.
Institute of Scientific and Technical Information of China (English)
Mehran Vahdani Moghaddam; Zeynab Chenari; Hamid Latifi; Vladimir Vladimirovich Shuvalov; Konestantin Valentinovich Rudenko
2008-01-01
@@ We deal with computer simulation of a transient process in a self-pumped phase conjugate plane-curve loop mirror based on BaTiO3. In optimal circumstances the nonlinear reflectivity and fidelity of such a mirror respectively achieve 0.80-0.90 and 0.95-0.98. The generation of conjugate wave-front occurs due to scattering from the dynamic hologram which is produced in the region of self-intersection of forward and backward beams. In such a model the scenario of passing to unstable generation regimes is similar to the self-pumped phase conjugate plane-plane loop mirror and substantially differs from a single-crystal double phase conjugate mirror.
Energy Technology Data Exchange (ETDEWEB)
Saelthun, Nils Roar [ed.; Tveito, Ole Einar; Boensnes, Truls Erik; Roald, Lars A.
1997-07-30
This report establishes new regional growth curves for Norway for annual daily maximum floods based on the general extreme value distribution. The parameters of the regional distributions were estimated by the probability weighted moment method. The regions were established by the hierarchical cluster analysis. The homogeneity of each region was examined by use of Wilt shires R-test. New regional formulae were established linking the mean annual flood to basin characteristics. The results have been compared to the previous set of regional growth curves and regional formulae predicting the mean annual flood. The relation between peak flood and daily values has been examined. A formula for predicting peak flood quantiles for a given daily flood quantile has been developed. 22 refs., 24 figs., 8 tabs.
Estimation for an additive growth curve model with orthogonal design matrices
Hu, Jianhua; You, Jinhong; 10.3150/10-BEJ315
2012-01-01
An additive growth curve model with orthogonal design matrices is proposed in which observations may have different profile forms. The proposed model allows us to fit data and then estimate parameters in a more parsimonious way than the traditional growth curve model. Two-stage generalized least-squares estimators for the regression coefficients are derived where a quadratic estimator for the covariance of observations is taken as the first-stage estimator. Consistency, asymptotic normality and asymptotic independence of these estimators are investigated. Simulation studies and a numerical example are given to illustrate the efficiency and parsimony of the proposed model for model specifications in the sense of minimizing Akaike's information criterion (AIC).
Soares, A C C; Guimarães, S E F; Kelly, M J; Fortes, M R S; E Silva, F F; Verardo, L L; Mota, R; Moore, S
2017-08-01
Fertility traits are economically important in cattle breeding programs. Scrotal circumference (SC) measures are repeatable, easily obtained, highly heritable, and positively correlated with female fertility traits and sperm quality traits in males. A useful approach to summarize SC measures over time is using nonlinear models, which summarize specific measures of SC in a few parameters with biological interpretation. This approach facilitates the selection of bulls with larger SC and maturity index (K), that is, early maturing animals. Because SC is a sex-limited trait, identifying the underlying genomics of growth curve parameters will allow selection across both males and females. We reported the first multitrait genomewide association study (GWAS) of estimated growth curve parameters for SC data in Brahman cattle. Five widely used nonlinear models were tested to fit a total of 3,612 SC records, measured at 6, 12, 18, and 24 mo of age. The von Bertalanffy model, individually fitted for each animal, best fit this SC data. Parameter estimates SC at maturity (A) and K as well as SC at all ages were jointly analyzed in a GWAS to identify 1-Mb regions most strongly associated with each trait. Heritabilities were 0.25 for K and 0.32 for A and ranged from 0.51 to 0.72 for SC at 6 (SC6), 12 (SC12), 18 (SC18), and 24 mo of age (SC24). An overlapping window on chromosome 14 explaining around 0.8% of genetic variance for K, SC12, SC18, and SC24 was observed. The major positional candidate genes within 1 Mb upstream and downstream of this overlapping window were , , , and . Windows of 1 Mb explaining more than 0.4% of each trait on chromosomes 1, 3, 6, 7, 14, 17, 18, 24, 25, and 26 were identified. Pathways and net-work analyses were indicated through transcription factors playing a role on fertility traits: , , , , , , and . Further validation studies on larger populations or other breeds are required to validate these findings and to improve our understanding of the
Evaluation of water beef buffalo from birth to two years using different growth curves
Directory of Open Access Journals (Sweden)
W.R. Lamberson
2010-02-01
Full Text Available The buffalo is a domestic animal species of growing world-wide importance. Research to improve genetic improvement programs is important to maintain the productivity of buffalo. The objective this research was to evaluate the growth of Brazilian buffalo to two years of age with different growth curves. Growth curves consolidate the information contained in the weight-age data into three or four biologically meaningful parameters. The data included 31,452 weights at birth and 120, 205, 365, 550 and 730 days of buffalo (n = 5,178 raised on pasture without supplementation. Logistic, Gompertz, quadratic logarithmic, and linear hyperbolic curves (designated L, G, QL, and LH, respectively were fitted to the data by using proc NLIN of SAS (SAS Institute, Inc., Cary, NC, USA. The parameters estimates for L [WT= A * (((1 + exp (-k * AGE**-m] were A = 865.1 ± 5.42; k= 0.0028 ± 0.00002; M= 3.808 ± 0.007; R2 = 0.95. For G [WT= A * exp (-b * exp (-k * age] the parameters estimates were A= 967.6 ± 7.23; k = 0.00217 ± 0.000015; b = -2.8152 ± 0.00532. For QL [WT= A + b*age + k*(age*age + m*log (age] parameters estimates were A= 37.41 ± 0.48; k= 0.00019 ± 6.4E-6; b= 0.539 ± 0.006; m= 2.32 ± 0.23; R2=0.96. For LH [WT= A + b*AGE + k*(1/AGE] the parameters estimates were A= 23.15 ± 0.44; k=15.16 ± 0.66; b= 0.707 ± 0.001; R2= 0.96. Each of these curves fit these data equally well and could be used for characterizing growth to two years in beef buffalo.
Solution Growth of a Novel Nonlinear Optical Material: L-Histidine Tetrafluoroborate
Aggarwal, M. D.; Choi, J.; Wang, W. S.; Bhat, K.; Lal, R. B.; Shields, Angela D.; Penn, Benjamin G.; Frazier, Donald O.
1998-01-01
Single crystals of L-Histidine tetrafluoroborate (L-HFB), a semiorganic nonlinear optical (NLO) material have been successfully grown by the temperature lowering and evaporation methods in our laboratory. Solubility curves of L-HFB have been determined in different solvents, such as water, ethanol and acetone. The solubility of L-HFB is very low in acetone, and ethanol, therefore, it is not feasible to grow L-HFB single crystals using these solvents. Good quality single crystals of a novel nonlinear optical material L-HFB have been grown from aqueous solution. Effects of seed orientation on morphologies of L-HFB crystals were studied. The advantages and disadvantage of both the evaporation and the temperature lowering techniques are compared. The single crystals in size 20 x 20 x 10 cubic mm were grown with deionized water as solvent in two weeks with an approximate growth rate of 1.4mm/day. The transmission range for these crystals has been found to be from 250 nm to 1500 nm.
First Versus Second Order Latent Growth Curve Models: Some Insights From Latent State-Trait Theory.
Geiser, Christian; Keller, Brian; Lockhart, Ginger
2013-07-01
First order latent growth curve models (FGMs) estimate change based on a single observed variable and are widely used in longitudinal research. Despite significant advantages, second order latent growth curve models (SGMs), which use multiple indicators, are rarely used in practice, and not all aspects of these models are widely understood. In this article, our goal is to contribute to a deeper understanding of theoretical and practical differences between FGMs and SGMs. We define the latent variables in FGMs and SGMs explicitly on the basis of latent state-trait (LST) theory and discuss insights that arise from this approach. We show that FGMs imply a strict trait-like conception of the construct under study, whereas SGMs allow for both trait and state components. Based on a simulation study and empirical applications to the CES-D depression scale (Radloff, 1977) we illustrate that, as an important practical consequence, FGMs yield biased reliability estimates whenever constructs contain state components, whereas reliability estimates based on SGMs were found to be accurate. Implications of the state-trait distinction for the measurement of change via latent growth curve models are discussed.
Alves, Larissa A.; de Castro, Arthur H.; de Mendonça, Fernanda G.; de Mesquita, João P.
2016-05-01
The oxygenated functional groups present on the surface of carbon dots with an average size of 2.7 ± 0.5 nm were characterized by a variety of techniques. In particular, we discussed the fit data of potentiometric titration curves using a nonlinear regression method based on the Levenberg-Marquardt algorithm. The results obtained by statistical treatment of the titration curve data showed that the best fit was obtained considering the presence of five Brønsted-Lowry acids on the surface of the carbon dots with constant ionization characteristics of carboxylic acids, cyclic ester, phenolic and pyrone-like groups. The total number of oxygenated acid groups obtained was 5 mmol g-1, with approximately 65% (∼2.9 mmol g-1) originating from groups with pKa < 6. The methodology showed good reproducibility and stability with standard deviations below 5%. The nature of the groups was independent of small variations in experimental conditions, i.e. the mass of carbon dots titrated and initial concentration of HCl solution. Finally, we believe that the methodology used here, together with other characterization techniques, is a simple, fast and powerful tool to characterize the complex acid-base properties of these so interesting and intriguing nanoparticles.
Hyánková, L; Knízetová, H; Dĕdková, L; Hort, J
2001-12-01
1. HG and LG quail lines selected for high and low relative weight gain between 11 and 28 d of age (RG11-28), respectively, and an unselected C line were compared. Mature body weight of both selected lines was held at that of the C line. Progeny of generation 6 were used for analysis. 2. Divergent selection for RG11-28 brought about opposite changes in the growth rates shortly after hatching. 3. Parameters of the Richards function were used to describe the growth curve. The largest differences between HG and LG lines occurred in age (t+) and body weight (y+) at the inflection point of the growth curve (on average for both sexes 28% and 20%, respectively). For HG quail, the parameter t+ was 5 d later than that for LG quail (18.6 vs 14.1 d for males and 20.6 vs 15.6 d for females, respectively), and consequently the parameter y+ was greater (90.3 vs 84.0 g for males and 104.5 vs 96.1 g for females, respectively). The shape of the growth curve expressed by the y+/A ratio was substantialy different for HG and LG quail (44.8% vs 39.6% for males and 43.5% vs 36.8% for females, respectively). 4. The food/gain ratios for the fattening period (3 to 35 d of age) were 3.21, 3.47 and 3.34 for the HG, LG and C lines, respectively. The HG quail started to utilise food more efficiently than the LG quail as early as 10 to 14 d, that is, at the age when their relative growth rate first became greater. 5. The relative deviations of the HG and LG lines from the C line are discussed.
Energy Technology Data Exchange (ETDEWEB)
Huang, Wei Ming; Lee, Grace W.M. [Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Road, Taipei 106 (China); Wu, Chih Cheng [Energy and Air Pollution Control Section, New Materials R and D Department, China Steel Corporation, 1, Chung-Kang Road, Siaogang District, Kaohsiung 81233 (China)
2008-01-15
The Kyoto Protocol attempts through political negotiations to guide participating industrialized countries' greenhouse gas (GHG) emissions from a positive growing trend, to reach a peak point (or turning point), and then be reduced to a negative growth. That means the relationship between decreasing GHG emissions and economic growth may be described by an inverted-U curve (or called a bell-shaped curve), which is consistent with the concept of the Environmental Kuznets Curve (EKC) hypothesis. This research observed that the economic development and GHG emissions in Economies in Transition (EITs) exhibit a hockey-stick curve trend (or called quasi-L-shape curve), that also generates a lot of 'hot air' which is significant to the implementation of the Kyoto Protocol. In addition, through the analysis of single-country time series data and GDP data, this research demonstrated that statistical data for most of the Annex II countries do not possess evidence that supports the EKC hypothesis for GHG emissions. The results from this study also indicated that the 38 industrialized countries are unable to meet their targets under the Kyoto Protocol within the specified time period, which are probably caused by the econometric method's inability to predict accurately the extents and development of innovative technologies and Clean Development Mechanism (CDM) projects. If the international community truly wants to reduce the GHG emissions, the effectiveness of the existing international framework for emissions reduction needs to be reconsidered seriously, and the global cooperation mechanism also needs to be greatly enhanced. (author)
Energy Technology Data Exchange (ETDEWEB)
Huang Weiming [Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Road, Taipei 106, Taiwan (China); Lee, Grace W.M. [Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Road, Taipei 106, Taiwan (China)], E-mail: gracelee@ntu.edu.tw; Wu Chihcheng [Energy and Air Pollution Control Section, New Materials R and D Department, China Steel Corporation, 1, Chung-Kang Road, Siaogang District, Kaohsiung 81233, Taiwan (China)
2008-01-15
The Kyoto Protocol attempts through political negotiations to guide participating industrialized countries' greenhouse gas (GHG) emissions from a positive growing trend, to reach a peak point (or turning point), and then be reduced to a negative growth. That means the relationship between decreasing GHG emissions and economic growth may be described by an inverted-U curve (or called a bell-shaped curve), which is consistent with the concept of the Environmental Kuznets Curve (EKC) hypothesis. This research observed that the economic development and GHG emissions in Economies in Transition (EITs) exhibit a hockey-stick curve trend (or called quasi-L-shape curve), that also generates a lot of 'hot air' which is significant to the implementation of the Kyoto Protocol. In addition, through the analysis of single-country time series data and GDP data, this research demonstrated that statistical data for most of the Annex II countries do not possess evidence that supports the EKC hypothesis for GHG emissions. The results from this study also indicated that the 38 industrialized countries are unable to meet their targets under the Kyoto Protocol within the specified time period, which are probably caused by the econometric method's inability to predict accurately the extents and development of innovative technologies and Clean Development Mechanism (CDM) projects. If the international community truly wants to reduce the GHG emissions, the effectiveness of the existing international framework for emissions reduction needs to be reconsidered seriously, and the global cooperation mechanism also needs to be greatly enhanced.
Energy Technology Data Exchange (ETDEWEB)
Szabó, Róbert; Ivezić, Željko; Kiss, László L.; Kolláth, Zoltán [Konkoly Observatory, MTA CSFK, Konkoly Thege Miklós út 15-17, H-1121 Budapest (Hungary); Jones, Lynne; Becker, Andrew C.; Davenport, James R. A. [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Sesar, Branimir [Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA 91125 (United States); Cutri, Roc M., E-mail: rszabo@konkoly.hu [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)
2014-01-01
We present and discuss an extensive data set for the non-Blazhko ab-type RR Lyrae star SDSS J015450+001501, including optical Sloan Digital Sky Survey ugriz light curves and spectroscopic data, LINEAR and Catalina Sky Survey unfiltered optical light curves, and infrared Two Micron All Sky Survey (2MASS) JHK{sub s} and Wide-field Infrared Survey Explorer W1 and W2 light curves. Most notable is that light curves obtained by 2MASS include close to 9000 photometric measures collected over 3.3 yr and provide an exceedingly precise view of near-infrared variability. These data demonstrate that static atmosphere models are insufficient to explain multiband photometric light-curve behavior and present strong constraints for nonlinear pulsation models for RR Lyrae stars. It is a challenge to modelers to produce theoretical light curves that can explain data presented here, which we make publicly available.
Growth curve analysis of birds: the Richards model and procedural problems. [Tachycineta bicolor
Energy Technology Data Exchange (ETDEWEB)
Zach, R.; Liner, Y.; Rigby, G.L.; Mayoh, K.R.
1984-01-01
Four sigmoid growth curve models for birds were compared using the daily body masses and primary-feather lengths of 35 nestling tree swallows (Tachycineta bicolor). The Richards model was superior to the von Bertalanffy, Gompertz, and logistic models for body mass, but not for primary-feather length. The latter models have fixed growth forms and are special cases of the flexible Richards model. Owing to parameter correlations, the Richards model was very sensitive to the starting parameter values for the numerical computer fitting routines. The lack of data leading up to the asymptote made it difficult to calculate good starting values for primary-feather length. None of the models tested was completely satisfactory for primary-feather length, as indicated by nonrandomly distributed residuals over time. The log transformation was appropriate for body mass. It homogenized the residual variances and increased the explained percentage of variation. The explained percentage of variation was a useful selection criterion for the best-fitting model, especially since it was directly related to randomness in the distribution of the residuals and homogeneity of residual variances. However, even percentages of variation exceeding 99.5%, did not necessarily indicate an excellent fit. The Richards model did not yield more model parameters for growth curve analysis, because the shape parameter and the growth rate constant were almost perfectly correlated.
STANDARD GROWTH CURVE FOR CHUB (Leuciscus cephalus L. 1758 IN CROATIA
Directory of Open Access Journals (Sweden)
Tomislav Treer
1997-04-01
Full Text Available Chub (Leuciscus cephalus is widely spread fish species and it inhabits most of Europe and some parts of Asia. It is also the dweller of different sections of rivers and stagnant waters and it eats both - animal and plant organisms. Thus, it is a very useful species when different habitats, or same biotopes over the period of time are being compared. Based on a number of published data on different habitats, the standard growth curve for chub in Croatia was calculated. Based on total length, Von Bertalanffy's growth curve appears to be: Lt = 31,8 (1-e-0,28(t-0,04 A comparative growth index for the first eight years of chub life was the lowest in the upper Kupa river (89,8 % and the best in the upper part of the Lonja river (112,2 %. The overall growth performance (phi-prime is ϕ`=5,69±O,14. These data are discussed and compared with literature.
Nonlinear Dynamics of Biofilm Growth on Sediment Surfaces
Molz, F. J.; Murdoch, L. C.; Faybishenko, B.
2013-12-01
Bioclogging often begins with the establishment of small colonies (microcolonies), which then form biofilms on the surfaces of a porous medium. These biofilm-porous media surfaces are not simple coatings of single microbes, but complex assemblages of cooperative and competing microbes, interacting with their chemical environment. This leads one to ask: what are the underlying dynamics involved with biofilm growth? To begin answering this question, we have extended the work of Kot et al. (1992, Bull. Mathematical Bio.) from a fully mixed chemostat to an idealized, one-dimensional, biofilm environment, taking into account a simple predator-prey microbial competition, with the prey feeding on a specified food source. With a variable (periodic) food source, Kot et al. (1992) were able to demonstrate chaotic dynamics in the coupled substrate-prey-predator system. Initially, deterministic chaos was thought by many to be mainly a mathematical phenomenon. However, several recent publications (e.g., Becks et al, 2005, Nature Letters; Graham et al. 2007, Int. Soc Microb. Eco. J.; Beninca et al., 2008, Nature Letters; Saleh, 2011, IJBAS) have brought together, using experimental studies and relevant mathematics, a breakthrough discovery that deterministic chaos is present in relatively simple biochemical systems. Two of us (Faybishenko and Molz, 2013, Procedia Environ. Sci)) have numerically analyzed a mathematical model of rhizosphere dynamics (Kravchenko et al., 2004, Microbiology) and detected patterns of nonlinear dynamical interactions supporting evidence of synchronized synergetic oscillations of microbial populations, carbon and oxygen concentrations driven by root exudation into a fully mixed system. In this study, we have extended the application of the Kot et al. model to investigate a spatially-dependent biofilm system. We will present the results of numerical simulations obtained using COMSOL Multi-Physics software, which we used to determine the nature of the
1992-02-13
niobate and absolute measurements of nonlinear optical coefficients of six different commonly used nonlinear optical materials. The refractometry data for...applied radiation and is now an established technology for Nd:YAG lasers. Optical parametric oscillation and amplification provide a method of generating...continuously tunable output -3- The relative advantages of nonlinear optical frequency conversion compared to other methods for the generation of near
An introduction to latent variable growth curve modeling concepts, issues, and application
Duncan, Terry E; Strycker, Lisa A
2013-01-01
This book provides a comprehensive introduction to latent variable growth curve modeling (LGM) for analyzing repeated measures. It presents the statistical basis for LGM and its various methodological extensions, including a number of practical examples of its use. It is designed to take advantage of the reader's familiarity with analysis of variance and structural equation modeling (SEM) in introducing LGM techniques. Sample data, syntax, input and output, are provided for EQS, Amos, LISREL, and Mplus on the book's CD. Throughout the book, the authors present a variety of LGM techniques that are useful for many different research designs, and numerous figures provide helpful diagrams of the examples.Updated throughout, the second edition features three new chapters-growth modeling with ordered categorical variables, growth mixture modeling, and pooled interrupted time series LGM approaches. Following a new organization, the book now covers the development of the LGM, followed by chapters on multiple-group is...
Grady, Matthew W.; Beretvas, S. Natasha
2010-01-01
Multiple membership random effects models (MMREMs) have been developed for use in situations where individuals are members of multiple higher level organizational units. Despite their availability and the frequency with which multiple membership structures are encountered, no studies have extended the MMREM approach to hierarchical growth curve…
Directory of Open Access Journals (Sweden)
Paula Beatriz Araujo
2004-03-01
Full Text Available The terrestrial isopod Atlantoscia floridana (van Name, 1940 occurs from the U.S.A. (Florida to Brazil and Argentina. In the southernmost Brazilian State, Rio Grande do Sul, the species is recorded in many localities, in urban and in non-urban areas. The growth curve of Atlantoscia floridana based on field data is presented. The specimens were sampled from April, 2000 to October, 2001 at the Reserva Biológica do Lami (RBL, Rio Grande do Sul. Captured individuals were sexed and had their cephalothorax width measured, with the data analyzed with von Bertalanffy's model. The growth curves for males and females are described, respectively, by the equations: Wt = 1.303 [1 - e-0.00941 (t + 50.37] and Wt = 1.682 [1 - e-0.00575 (t + 59.13]. The curves showed differential growth between sexes, where females reach a higher Wµ with a slower growth rate. Based on the growth curves it was also possible to estimate life expectancy for males and females.O isópodo terrestre Atlantoscia floridana (van Name, 1940 ocorre desde os Estados Unidos (Flórida até o Brasil e Argentina. No Rio Grande do Sul a espécie é registrada em muitas localidades, em áreas urbanas e não-urbanas. Este trabalho apresenta a curva de crescimento de Atlantoscia floridana, baseada em dados de campo. Os espécimes foram amostrados desde abril, 2000 a outubro, 2001 na Reserva Biológica do Lami (RBL, Rio Grande do Sul. Os indivíduos capturados foram sexados e tiveram o cefalotórax medido. Os dados foram analisados utilizando-se o modelo de von Bertalanffy. A curva de crescimento para machos e fêmeas são descritas, respectivamente, pelas equações Wt = 1.303 [1 - e-0.00941 (t + 50.37] e Wt = 1.682 [1 - e -0.00575 (t + 59.13]. As curvas mostraram crescimento diferencial entre os sexos, onde as fêmeas atingem o maior Wµ com uma taxa de crescimento menor. Com base nas curvas de crescimento também foi possível estimar a expectativa de vida para machos e fêmeas.
Koivula, M; Sevón-Aimonen, M-L; Strandén, I; Matilainen, K; Serenius, T; Stalder, K J; Mäntysaari, E A
2008-06-01
This paper's objectives were to estimate the genetic (co)variance components of the Gompertz growth curve parameters and to evaluate the relationship of estimated breeding values (EBV) based on average daily gain (ADG) and Gompertz growth curves. Finnish Yorkshire central test station performance data was obtained from the Faba Breeding (Vantaa, Finland). The final data set included 121,488 weight records from 10,111 pigs. Heritability estimates for the Gompertz growth parameters mature weight (alpha), logarithm of mature weight to birth weight ratio (beta) and maturation rate (kappa) were 0.44, 0.55 and 0.31, respectively. Genotypic and phenotypic correlations between the growth curve parameters were high and mainly negative. The only positive relationship was found between alpha and beta. Pearson and Spearman rank correlation coefficients between EBV for ADG and daily gain calculated from Gompertz growth curves were 0.79. The Spearman rank correlation between the sire EBV for ADG and Gompertz growth curve parameter-based ADG for all sires with at least 15 progeny was 0.86. Growth curves differ significantly between individuals and this information could be utilized for selection purposes when improving growth rate in pigs.
Kort-Butler, Lisa A; Hagewen, Kellie J
2011-05-01
Research on adolescent self-esteem indicates that adolescence is a time in which individuals experience important changes in their physical, cognitive, and social identities. Prior research suggests that there is a positive relationship between an adolescent's participation in structured extracurricular activities and well-being in a variety of domains, and some research indicates that these relationships may be dependent on the type of activities in which adolescents participate. Building on previous research, a growth-curve analysis was utilized to examine self-esteem trajectories from adolescence (age 14) to young adulthood (age 26). Using 3 waves of data from National Longitudinal Study of Adolescent Health (n = 5,399; 47.8% male), the analysis estimated a hierarchical growth-curve model emphasizing the effects of age and type of school-based extracurricular activity portfolio, including sports and school clubs, on self-esteem. The results indicated that age had a linear relationship with self-esteem over time. Changes in both the initial level of self-esteem and the growth of self-esteem over time were significantly influenced by the type of extracurricular activity portfolio. The findings were consistent across race and sex. The results support the utility of examining the longitudinal impact of portfolio type on well-being outcomes.
Directory of Open Access Journals (Sweden)
Rachana Patel
2014-01-01
Full Text Available Objectives: Growth curves are the most important tools for the assessment of growth of children, which could further helps to develop preventive interventions. Geographical and physical differences necessitate using national growth curves. This study aims to construct growth curves using anthropometric measurements namely weight and height for Indian children using cross-sectional data from National Family and Health Surveys. Materials and Methods: Box-Cox power exponential, a flexible distribution, was used that offers to adjust kurtosis and improves the estimation of extreme percentiles. LMS-methods that fit skewed data adequately and generate fitted curves that follow closely the empirical data, with maximum penalized likelihood, Akaike information criteria (AIC and generalized AIC with penalty 3 were used to construct the growth curves. Before fittings this model factors which influence the nutritional status of children were examined, similar to World Health Organization (WHO (2006 factors, namely standard infant feeding practices, sanitation, non-smoking mothers additionally poverty (household consumable assets based. Results: Model fitted in LMS-model and standard based on height and weight for children aged 0-60 months was obtained after iteration for degrees of freedom for the parameters. Growth curves for mean Z-scores and percentiles were constructed for both sexes and significant lower values were noticeably found to be set as growth-standard compared to WHO-standards. Conclusion: Study showed the prospect of constructing regional/national growth curve and their need for the assessment of children′s growth, which could help to identify undernourished-children at national level. There is an urgent need to collect longitudinal data of children to fit the growth curve of children in India.
Models for the analysis of growth curves for rearing tinamous (Rhynchotus rufescens in captivity
Directory of Open Access Journals (Sweden)
P Tholon
2007-03-01
Full Text Available Growth curves models provide a visual assessment of growth as a function of time, and prediction body weight at a specific age. This study aimed at estimating tinamous growth curve using different models, and at verifying their goodness of fit. A total number 11,639 weight records from 411 birds, being 6,671 from females and 3,095 from males, was analyzed. The highest estimates of a parameter were obtained using Brody (BD, von Bertalanffy (VB, Gompertz (GP, and Logistic function (LG. Adult females were 5.7% heavier than males. The highest estimates of b parameter were obtained in the LG, GP, BD, and VB models. The estimated k parameter values in decreasing order were obtained in LG, GP, VB, and BD models. The correlation between the parameters a and k showed heavier birds are less precocious than the lighter. The estimates of intercept, linear regression coefficient, quadratic regression coefficient, and differences between quadratic coefficient of functions and estimated ties of quadratic-quadratic-quadratic segmented polynomials (QQQSP were: 31.1732±2.41339; 3.07898± 0.13287; 0.02689±0.00152; -0.05566±0.00193; 0.02349±0.00107, and 57 and 145 days, respectively. The estimated predicted mean error values (PME of VB, GP, BD, LG, and QQQSP models were, respectively, 0.8353; 0.01715; -0.6939; -2.2453; and -0.7544%. The coefficient of determination (R² and least square error values (MS showed similar results. In conclusion, the VB and the QQQSP models adequately described tinamous growth. The best model to describe tinamous growth was the Gompertz model, because it presented the highest R² values, easiness of convergence, lower PME, and the easiness of parameter biological interpretation.
BAYESIAN LOCAL INFLUENCE ASSESSMENTS IN A GROWTH CURVE MODEL WITH GENERAL COVARIANCE STRUCTURE
Institute of Scientific and Technical Information of China (English)
2000-01-01
The objective of this paper is to present a Bayesian approach based on Kullback Leibler divergence for assessing local influence in a growth curve model with general covariance structure.Under certain prior distribution assumption,the Kullback-Leibler divergence is used to measure the influence of some minor perturbation on the posterior distribution of unknown parameter.This leads to the diagnostic statistic for detecting which response is locally influential.As an application,the common covariance-weighted perturbation scheme is thoroughly considered.
A study on the growth curve of and maximum profit from layer-type cockerel chicks.
Gang, F Y; Zhen, Y S
1997-09-01
1. 2900 commercial layer-type cockerel chicks were reared on the floor from 1-day-old to 9 weeks of age. 2. The growth curve of the cockerel chicks was [formula see text] 3. The feeding costs (US$) of layer-type cockerel chicks were described by the equation Y = a + bx + cx2 = 0.0657 - 0.0091x + 0.0069x2. 4. When the layer-type cockerel chicks' marketing price was US$0.82 per kg. (6.8 Renminbi per kg), the optimum marketing age for maximum profit margin was 5.9 weeks (41 to 42 d).
Ground state solutions for nonlinear fractional Schrodinger equations involving critical growth
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Hua Jin
2017-03-01
Full Text Available This article concerns the ground state solutions of nonlinear fractional Schrodinger equations involving critical growth. We obtain the existence of ground state solutions when the potential is not a constant and not radial. We do not use the Ambrosetti-Rabinowitz condition, or the monotonicity condition on the nonlinearity.
National Research Council Canada - National Science Library
Selvaggi, Maria; Laudadio, Vito; Dario, Cataldo; Tufarelli, Vincenzo
2015-01-01
... it. This study was carried out to estimate the parameters of logistic, Gompertz and Richards growth curve models in a nondescript chicken breed population from southern Italy to determine the goodness of fit...
Nonlinear Schrodinger elliptic systems involving exponential critical growth in R^2
Directory of Open Access Journals (Sweden)
Francisco S. B. Albuquerque Albuquerque
2014-02-01
Full Text Available This article concerns the existence and multiplicity of solutions for elliptic systems with weights, and nonlinearities having exponential critical growth. Our approach is based on the Trudinger-Moser inequality and on a minimax theorem.
Volume-duration growth curves for flood estimation in permeable catchments
Directory of Open Access Journals (Sweden)
R. B. Bradford
2002-01-01
Full Text Available The volume and duration of groundwater discharge following extreme winter recharge events in permeable catchments can often be more disruptive than the peak discharge. An estimation procedure for annual maxima flood series in permeable catchments is extended to annual flood volumes for different durations. Growth factors for durations of 1 to 30 days and return periods of up to 250 years are derived for a sample of 12 permeable catchments in the UK. In most cases, adjusting the growth curves for ‘non-flood’ years has only a small effect and L-moment parameters show little change with duration. L-CV and L-skewness are highly correlated for the sample of Chalk catchments. Keywords: Chalk, groundwater flood estimation
Rong, Youmin; Zhang, Guojun; Huang, Yu
2016-10-01
Inherent strain analysis has been successfully applied to predict welding deformations of large-scale structural components, while thermal-elastic-plastic finite element method is rarely used for its disadvantages of long calculation period and large storage space. In this paper, a hybrid model considering nonlinear yield stress curves and multi-constraint equations to thermal-elastic-plastic analysis is further proposed to predict welding distortions and residual stresses of large-scale structures. For welding T-joint structural steel S355JR by metal active gas welding, the published experiment results of temperature and displacement fields are applied to illustrate the credibility of the proposed integration model. By comparing numerical results of four different cases with the experiment results, it is verified that prediction precision of welding deformations and residual stresses is apparently improved considering the power-law hardening model, and computational time is also obviously shortened about 30.14% using multi-constraint equations. On the whole, the proposed hybrid method can be further used to precisely and efficiently predict welding deformations and residual stresses of large-scale structures.
Sze, K. H.; Barsukov, I. L.; Roberts, G. C. K.
A procedure for quantitative evaluation of cross-peak volumes in spectra of any order of dimensions is described; this is based on a generalized algorithm for combining appropriate one-dimensional integrals obtained by nonlinear-least-squares curve-fitting techniques. This procedure is embodied in a program, NDVOL, which has three modes of operation: a fully automatic mode, a manual mode for interactive selection of fitting parameters, and a fast reintegration mode. The procedures used in the NDVOL program to obtain accurate volumes for overlapping cross peaks are illustrated using various simulated overlapping cross-peak patterns. The precision and accuracy of the estimates of cross-peak volumes obtained by application of the program to these simulated cross peaks and to a back-calculated 2D NOESY spectrum of dihydrofolate reductase are presented. Examples are shown of the use of the program with real 2D and 3D data. It is shown that the program is able to provide excellent estimates of volume even for seriously overlapping cross peaks with minimal intervention by the user.
Ruddock, Scott; Caeyenberghs, Karen; Piek, Jan; Sugden, David; Hyde, Christian; Morris, Sue; Rigoli, Daniela; Steenbergen, Bert; Wilson, Peter
2016-11-01
Previous research indicates that children with Developmental Coordination Disorder (DCD) show deficits performing online corrections, an issue exacerbated by adding inhibitory constraints; however, cross-sectional data suggests that these deficits may reduce with age. Using a longitudinal design, the aim of the study presented here was to model the coupling that occurs between inhibitory systems and (predictive) online control in typically developing children (TDC) and in those with Developmental Coordination Disorder (DCD) over an extended period of time, using a framework of interactive specialization. We predicted that TDC would show a non-linear growth pattern, consistent with re-organisation in the coupling during the middle childhood period, while DCD would display a developmental lag. A group of 196 children (111 girls and 85 boys) aged between 6 and 12years participated in the study. Children were classified as DCD according to research criteria. Using a cohort sequential design, both TDC and DCD groups were divided into age cohorts. Predictive (online) control was defined operationally by performance on a Double-Jump Reaching Task (DJRT), which was assessed at 6-month intervals over two years (5 time points in total). Inhibitory control was examined using an anti-jump condition of the DJRT paradigm whereby children were instructed to touch a target location in the hemispace opposite a cued location. For the TDC group, model comparison using growth curve analysis revealed that a quadratic trend was the most appropriate fit with evidence of rapid improvement in anti-reach performance up until middle childhood (around 8-9years of age), followed by a more gradual rate of improvement into late childhood and early adolescence. This pattern was evident on both chronometric and kinematic measures. In contrast, for children with DCD, a linear function provided the best to fit on the key metrics, with a slower rate of improvement than controls. We conclude that
Influences of altitude on growth curves in Tibetan chicken and its hybrid
Institute of Scientific and Technical Information of China (English)
2008-01-01
Tibetan chicken is a precious resource in Qinghai-Tibet Plateau,China.In order to study its growth rhythm and heterosis of its hybrid,three groups comprising Tibetan chicken (T),Dwarf Recessive White (D) and Tibetan×Dwarf Recessive White (TD) were reared under the same management conditions at low and high altitudes.Body weight and shank length were measured,and growth curves were fitted using Richards model.The results showed that the model fitted well with the chickens' growth courses in weight and shank with R2 at more than 0.99.The high-altitude might retard the growth of chickens,with decreases in inflection point values,final values and maximal growth rates,and prolongation of inflection point time.The final weight,inflection point weight,and maximal growth rates of Tibetan chicken were 1008.3 g,477.9 g and 11.69 g respectively at lowaltitude,and 525.3 g,229.5 g,and 5.12 g at high-altitude.This showed a decline of 47.9%,52.0%,and 56.8% at the high-altitude;the degree of influence of altitude was less than that of Dwarf Recessive White.The TD had high heterosis in weight gain,and at high-altitude the heterosis of final weight,inflection point weight,and maximal growth rates were 59.5%,56.8% and 52.3% respectively.Therefore,the Tibetan×Dwarf Recessive White cross was good for improving the Tibetan chicken.
Goldstein, Harvey; Leckie, George; Charlton, Christopher; Tilling, Kate; Browne, William J
2017-01-01
Aim To present a flexible model for repeated measures longitudinal growth data within individuals that allows trends over time to incorporate individual-specific random effects. These may reflect the timing of growth events and characterise within-individual variability which can be modelled as a function of age. Subjects and methods A Bayesian model is developed that includes random effects for the mean growth function, an individual age-alignment random effect and random effects for the within-individual variance function. This model is applied to data on boys' heights from the Edinburgh longitudinal growth study and to repeated weight measurements of a sample of pregnant women in the Avon Longitudinal Study of Parents and Children cohort. Results The mean age at which the growth curves for individual boys are aligned is 11.4 years, corresponding to the mean 'take off' age for pubertal growth. The within-individual variance (standard deviation) is found to decrease from 0.24 cm(2) (0.50 cm) at 9 years for the 'average' boy to 0.07 cm(2) (0.25 cm) at 16 years. Change in weight during pregnancy can be characterised by regression splines with random effects that include a large woman-specific random effect for the within-individual variation, which is also correlated with overall weight and weight gain. Conclusions The proposed model provides a useful extension to existing approaches, allowing considerable flexibility in describing within- and between-individual differences in growth patterns.
Finkel, Deborah; Davis, Deborah Winders; Turkheimer, Eric; Dickens, William T
2015-11-01
Biometric latent growth curve models were applied to data from the LTS in order to replicate and extend Wilson's (Child Dev 54:298-316, 1983) findings. Assessments of cognitive development were available from 8 measurement occasions covering the period 4-15 years for 1032 individuals. Latent growth curve models were fit to percent correct for 7 subscales: information, similarities, arithmetic, vocabulary, comprehension, picture completion, and block design. Models were fit separately to WPPSI (ages 4-6 years) and WISC-R (ages 7-15). Results indicated the expected increases in heritability in younger childhood, and plateaus in heritability as children reached age 10 years. Heritability of change, per se (slope estimates), varied dramatically across domains. Significant genetic influences on slope parameters that were independent of initial levels of performance were found for only information and picture completion subscales. Thus evidence for both genetic continuity and genetic innovation in the development of cognitive abilities in childhood were found.
Growth curve of locally adapted pantaneiro cows raised under natural conditions
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Eleonora Araújo Barbosa
2013-11-01
Full Text Available The objective of this study was to use morphometric and ultrasound evaluations to estimate the growth curve of the Pantaneiro cattle breed, raised in its natural habitat, aiming at the re-insertion of this breed in production systems. One hundred and three females, aging from months to 11 years, and raised on native pastures, were evaluated. The animals belonged to the Conservation Nucleus of Embrapa Pantanal, located in the Pantanal of Mato Grosso do Sul (Brazil. Weight, thoracic perimeter (TP, body length (BL, rump height (RH, height at withers (HW, hip height (HH, depth (DP, distance between the ilia (DI (cm and rib-eye area (REA were measured. To relate the measurements with the age of the animals, the univariate regression model was used, assigning the variable response to gamma distribution. The Pearson correlation between variables was also estimated. The inflection point of the growth curve was 37 months for HH; between 38 and 39 months for TP and HW; between 40 and 41 months for DI, HH and DP; and 45 months for BL. The REA results could not fit in a statistical model. The majority of the variables presented a correlation above 60% among themselves, except for REA × Age, of 15.81%; REA × HW, of 34.44%; HH × Age, of 46.19; HH × DI, of 58.07%; REA × HH, of 24.57%; and REA × TP, of 39.9%. The cows showed maturity age at 40 months, which may have occurred because they were raised in natural farming conditions. In Pantaneiro cows reared in extensive systems only on natural pastures, the use of ultrasound is not effective to estimate the curve of muscular development, perhaps because this breed was not selected for weight gain.
Liu, Siwei; Rovine, Michael J; Molenaar, Peter C M
2012-03-01
With increasing popularity, growth curve modeling is more and more often considered as the 1st choice for analyzing longitudinal data. Although the growth curve approach is often a good choice, other modeling strategies may more directly answer questions of interest. It is common to see researchers fit growth curve models without considering alterative modeling strategies. In this article we compare 3 approaches for analyzing longitudinal data: repeated measures analysis of variance, covariance pattern models, and growth curve models. As all are members of the general linear mixed model family, they represent somewhat different assumptions about the way individuals change. These assumptions result in different patterns of covariation among the residuals around the fixed effects. In this article, we first indicate the kinds of data that are appropriately modeled by each and use real data examples to demonstrate possible problems associated with the blanket selection of the growth curve model. We then present a simulation that indicates the utility of Akaike information criterion and Bayesian information criterion in the selection of a proper residual covariance structure. The results cast doubt on the popular practice of automatically using growth curve modeling for longitudinal data without comparing the fit of different models. Finally, we provide some practical advice for assessing mean changes in the presence of correlated data.
A multilevel nonlinear mixed-effects approach to model growth in pigs
DEFF Research Database (Denmark)
Strathe, Anders Bjerring; Danfær, Allan Christian; Sørensen, H
2009-01-01
Growth functions have been used to predict market weight of pigs and maximize return over feed costs. This study was undertaken to compare 4 growth functions and methods of analyzing data, particularly one that considers nonlinear repeated measures. Data were collected from an experiment with 40...... pigs maintained from birth to maturity and their BW measured weekly or every 2 wk up to 1,007 d. Gompertz, logistic, Bridges, and Lopez functions were fitted to the data and compared using information criteria. For each function, a multilevel nonlinear mixed effects model was employed because....... Furthermore, studies should consider adding continuous autoregressive process when analyzing nonlinear mixed models with repeated measures....
Quinn, Catherine A; Bussey, Kay
2015-10-01
Moral disengagement is a social cognitive process that has been extensively applied to transgressive behaviors, including delinquency, aggression and illicit substance use. However, there has been limited research on moral disengagement as it relates to underage drinking. The current study aimed to examine moral disengagement contextualized to underage drinking and its longitudinal relationship to alcohol use. Moreover, the social context in which adolescent alcohol use typically occurs was also considered, with a specific emphasis on the social sanctions, or social outcomes, that adolescents anticipate receiving from friends for their alcohol use. Adolescents were assessed across three time-points, 8 months apart. The longitudinal sample consisted of 382 (46% female) underage drinkers (12-16 years at T1). Parallel latent growth curve analysis was used to examine the bi-directional influence of initial moral disengagement, anticipated social outcomes, and alcohol use on subsequent growth in moral disengagement, anticipated social outcomes and alcohol use. The interrelation of initial scores and growth curves was also assessed. The findings revealed that, in the binary parallel analyses, initial moral disengagement and anticipated social outcomes both significantly predicted changes in alcohol use across time. Moreover, initial anticipated social outcomes predicted changes in moral disengagement. These findings were not consistently found when all three process analyses were included in a single model. The results emphasize the impact of social context on moral disengagement and suggest that by targeting adolescents' propensity to justify or excuse their drinking, as well as the social outcomes adolescents anticipate for being drunk, it may be possible to reduce their underage drinking.
Rayleigh-Taylor instability under curved substrates: An optimal transient growth analysis
Balestra, Gioele; Brun, P.-T.; Gallaire, François
2016-12-01
We investigate the stability of thin viscous films coated on the inside of a horizontal cylindrical substrate. In such a case, gravity acts both as a stabilizing force through the progressive drainage of the film and as a destabilizing force prone to form droplets via the Rayleigh-Taylor instability. The drainage solution, derived from lubrication equations, is found asymptotically stable with respect to infinitesimally small perturbations, although in reality, droplets often form. To resolve this paradox, we perform an optimal transient growth analysis for the first-order perturbations of the liquid's interface, generalizing the results of Trinh et al. [Phys. Fluids 26, 051704 (2014), 10.1063/1.4876476]. We find that the system displays a linear transient growth potential that gives rise to two different scenarios depending on the value of the Bond number (prescribing the relative importance of gravity and surface tension forces). At low Bond numbers, the optimal perturbation of the interface does not generate droplets. In contrast, for higher Bond numbers, perturbations on the upper hemicircle yield gains large enough to potentially form droplets. The gain increases exponentially with the Bond number. In particular, depending on the amplitude of the initial perturbation, we find a critical Bond number above which the short-time linear growth is sufficient to trigger the nonlinear effects required to form dripping droplets. We conclude that the transition to droplets detaching from the substrate is noise and perturbation dependent.
Prediction of Experimental Rainfall-Eroded Soil Area Based on S-Shaped Growth Curve Model Framework
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Wen Nie
2015-07-01
Full Text Available Rainfall-induced soil erosion of a mountain area plays a significant role in supplying sediment and shaping the landscape. The related area of soil erosion, as an index of the changed landscape, is easier to calculate visually using some popular imaging tools. By image analysis, our work shows that the changing of the soil erosion area admits the structure of an S-growth curve. Therefore, we propose to establish an S-curve model, based on incremental learning, to predict the soil erosion area. In the process of incremental learning, we dynamically update the accumulative rainfall and rainfall intensity to train the parameters of our S-curve model. In order to verify our prediction model, the index of area is utilized to express the output of eroded soil in a series of experiments. The results show that the proposed S-growth curve model can be used to estimate the growth of the soil erosion area (average relative error 3%–9.7% according to variable soil material and rainfall intensity. The original S-growth curve model can calculate the erosion areas of just one soil material and one rainfall condition whose average relative error is 7.5%–12.2%; compared to the simple time series analysis-moving average method (average relative error 5.7%–12.1%, our proposed S-growth curve model can reveal the physical mechanism and evolution of the research object.
Growth curves and their implications in hand-fed Monk parrots (Myiopsitta monachus
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Petzinger C
2015-10-01
Full Text Available Christina Petzinger,1,2 J Jill Heatley,3 John E Bauer1,2 1Comparative Animal Nutrition Research Laboratory, Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, 2Intercollegiate Faculty of Nutrition, Texas A&M University, 3Zoological Medicine Service, Department of Small Animal Medicine and Surgery, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA Abstract: Monk parrots (Myiopsitta monachus were hand-fed over two chick seasons spanning of 2010 to 2011. Information from the growth curve of chicks hand-fed in 2010 was used to develop a feeding protocol for the 2011 season (Protocol-2011. This protocol addressed the problems of delayed followed by excessive growth experienced by parrots hand fed in 2010. Monk parrots that were hand-fed in 2011 following the new protocol experienced delayed growth after 20 days of age. However, some Monk parrots were fed in excess of Protocol-2011 and did not experience a major delay in growth. The energy requirement equations used to construct Protocol-2011 were low when compared to adult Monk parrot maintenance energy requirements. The data suggest that growing birds do not require approximately twice their adult maintenance energy requirements, as is the case for growing dogs. Additionally, there appear to be fluctuations in energy needs as Monk parrots grow. A major increase in energy needs occurred between days 18 and 23 posthatching, which corresponds to feather development and growth in Monk parrot chicks. Thus, multiple equations estimating energy requirements, rather than just one equation, are likely needed from hatching to fledging in order to ensure adequate energy is provided to chicks. More research on the energy requirements of growing Monk parrots, especially around the time of fledging and weaning, is needed to improve hand-fed methods and potentially the adult health of hand-fed birds. Keywords
Essays on the predictability of oil shocks and yield curves for real-time output growth
Carlton, Amelie B.
This dissertation is a collection of three essays that revisits the long-standing puzzle of the apparently disproportionate effect of oil prices in the economy by examining output growth predictability with real-time data. Each study of the predictive content of oil shocks is from a different perspective by using newly developed real-time datasets, which allows for replicating the economic environment faced by policymakers in real time. The first study extends the conventional set of models of output growth determination by investigating predictability of models that incorporate various functional forms of oil prices and real-time data. The results are supportive of the relationship of GDP and oil in the context of Granger causality with real-time data. In the second essay, I use oil shocks to predict the economy is changing direction earlier than would be predicted by solely using initial GDP releases. The model provides compelling evidence of negative GDP growth predictability in response to oil price shocks, which could shorten the "recognition lag" for successful implementation of discretionary counter-cyclical policies. In the third essay, I evaluate short-horizon output growth predictability using real-time data for different sample periods. I find strong evidence of predictability at the one-quarter and four-quarter horizon for the United States. The major result of the paper is that we reject the null hypothesis of no predictability against an alternative hypothesis of predictability with oil shocks that include yield curves in the forecasting regression. This relationship suggests the combination of monetary policy and oil shocks are important for subsequent GDP growth.
Energy Technology Data Exchange (ETDEWEB)
Fodha, Mouez [Paris School of Economics and CES, University Paris 1 Pantheon-Sorbonne, Maison des Sciences Economiques, 106-112 Bd de l' Hopital, 75647 Paris (France); Zaghdoud, Oussama [CES, University Paris 1 Pantheon-Sorbonne and Department of Economics, High School of Economic and Commercial Sciences of Tunis, 4 Rue Abou Zakaria El Hafsi, 1089 Montfleury (Tunisia)
2010-02-15
This paper investigates the relationship between economic growth and pollutant emissions for a small and open developing country, Tunisia, during the period 1961-2004. The investigation is made on the basis of the environmental Kuznets curve hypothesis, using time series data and cointegration analysis. Carbon dioxide (CO{sub 2}) and sulfur dioxide (SO{sub 2}) are used as the environmental indicators, and GDP as the economic indicator. Our results show that there is a long-run cointegrating relationship between the per capita emissions of two pollutants and the per capita GDP. An inverted U relationship between SO{sub 2} emissions and GDP has been found, with income turning point approximately equals to 1200 (constant 2000 prices) or to 3700 (in PPP, constant 2000 prices). However, a monotonically increasing relationship with GDP is found more appropriate for CO{sub 2} emissions. Furthermore, the causality results show that the relationship between income and pollution in Tunisia is one of unidirectional causality with income causing environmental changes and not vice versa, both in the short-run and long-run. This implies that an emission reduction policies and more investment in pollution abatement expense will not hurt economic growth. It could be a feasible policy tool for Tunisia to achieve its sustainable growth in the long-run. (author)
Energy Technology Data Exchange (ETDEWEB)
Fodha, Mouez, E-mail: fodha@univ-paris1.f [Paris School of Economics and CES, University Paris 1 Pantheon-Sorbonne, Maison des Sciences Economiques, 106-112 Bd de l' Hopital, 75647 Paris (France); Zaghdoud, Oussama [CES, University Paris 1 Pantheon-Sorbonne and Department of Economics, High School of Economic and Commercial Sciences of Tunis, 4 Rue Abou Zakaria El Hafsi, 1089 Montfleury (Tunisia)
2010-02-15
This paper investigates the relationship between economic growth and pollutant emissions for a small and open developing country, Tunisia, during the period 1961-2004. The investigation is made on the basis of the environmental Kuznets curve hypothesis, using time series data and cointegration analysis. Carbon dioxide (CO{sub 2}) and sulfur dioxide (SO{sub 2}) are used as the environmental indicators, and GDP as the economic indicator. Our results show that there is a long-run cointegrating relationship between the per capita emissions of two pollutants and the per capita GDP. An inverted U relationship between SO{sub 2} emissions and GDP has been found, with income turning point approximately equals to $1200 (constant 2000 prices) or to $3700 (in PPP, constant 2000 prices). However, a monotonically increasing relationship with GDP is found more appropriate for CO{sub 2} emissions. Furthermore, the causality results show that the relationship between income and pollution in Tunisia is one of unidirectional causality with income causing environmental changes and not vice versa, both in the short-run and long-run. This implies that an emission reduction policies and more investment in pollution abatement expense will not hurt economic growth. It could be a feasible policy tool for Tunisia to achieve its sustainable growth in the long-run.
Estimating Gompertz Growth Curves from Marine Mammal Strandings in the Presence of Missing Data.
Shotwell, Mary; McFee, Wayne; Slate, Elizabeth H
2010-01-01
Stranded bottlenose dolphins (Tursiops truncatus) off the coast of South Carolina (SC) provide data essential for population health assessment. Of the 598 bottlenose dolphin strandings in SC from 1993 to 2007, 91 were of sufficient body condition to obtain organ weights. Of these 91 animals, only 52 were brought back to the laboratory for total body weight measurements. Because it is more feasible to transport smaller animals to the laboratory setting for necropsy procedures, a selection bias is present in that data for larger animals are often missing. Regression and propensity score multiple imputation methods are utilized to account for missing data needed to compute growth. Fitted Gompertz growth curves for SC animals with and without adjustment for missing data are compared to those found from the northwestern Gulf of Mexico. South Carolina animals display a trend in lower asymptotic mean total body weights and faster growth rates compared to the Gulf of Mexico population. The differences generally increased in magnitude after imputation methods. South Carolina females were originally estimated to reach larger maximum sizes than Gulf of Mexico females, but after imputation this relationship reversed. The findings suggest selection bias should be accounted for in sampling stranded dolphins.
Directory of Open Access Journals (Sweden)
Alun Gu
2017-07-01
Full Text Available Global inequity and the unbalance of water resources has been a critical issue for many years; and the Chinese per capita water resources are only 1/4 of the global average. Meanwhile, as the Chinese economy is growing rapidly, the demand of Chinese industrial water use is also increasing. In this case, it is important to balance the relationship between economic growth and industrial water use. In this study, a reduction model is established for the northeastern, northern coastal, eastern coastal, southern coastal, middle Yellow River, middle Yangtze River, southwestern, and northwestern regions to verify the environmental Kuznets curve (EKC for their respective industrial water use and provide theoretical support for decision making from an economic perspective. It adopts the per capita industrial water use and GDP of the eight economic zones from 2002 to 2014. The unit root test and co-integration test were adopted to analyze the stationarity of the data, and the triple reduction model was used for the fitting of variables. The relationship between per capita industrial water use and GDP showed an inverted U-shaped curve from 2002 to 2014 for China, as well as for the eastern coastal and middle Yangtze River regions, with the coordinates of the turning points being (9.8749, 4.6735, (10.3098, 5.4783, and (9.8184, 5.0622, respectively. The per capita GDP at the turning point of the inverted U-shaped curve is 18,000–30,000 Yuan (at constant prices from 2000. This study provides important thoughts and lessons for collaborative research into the relationship between industrial water consumption and economic development. The central government should focus on the central and western regions when creating policies for water resource management and technological development to improve their industrial water use efficiency.
Factors influencing community health centers' efficiency: a latent growth curve modeling approach.
Marathe, Shriram; Wan, Thomas T H; Zhang, Jackie; Sherin, Kevin
2007-10-01
The objective of study is to examine factors affecting the variation in technical and cost efficiency of community health centers (CHCs). A panel study design was formulated to examine the relationships among the contextual, organizational structural, and performance variables. Data Envelopment Analysis (DEA) of technical efficiency and latent growth curve modeling of multi-wave technical and cost efficiency were performed. Regardless of the efficiency measures, CHC efficiency was influenced more by contextual factors than organizational structural factors. The study confirms the independent and additive influences of contextual and organizational predictors on efficiency. The change in CHC technical efficiency positively affects the change in CHC cost efficiency. The practical implication of this finding is that healthcare managers can simultaneously optimize both technical and cost efficiency through appropriate use of inputs to generate optimal outputs. An innovative solution is to employ decision support software to prepare an expert system to assist poorly performing CHCs to achieve better cost efficiency through optimizing technical efficiency.
A Markovian Growth Dynamics on Rooted Binary Trees Evolving According to the Gompertz Curve
Landim, C.; Portugal, R. D.; Svaiter, B. F.
2012-08-01
Inspired by biological dynamics, we consider a growth Markov process taking values on the space of rooted binary trees, similar to the Aldous-Shields (Probab. Theory Relat. Fields 79(4):509-542, 1988) model. Fix n≥1 and β>0. We start at time 0 with the tree composed of a root only. At any time, each node with no descendants, independently from the other nodes, produces two successors at rate β( n- k)/ n, where k is the distance from the node to the root. Denote by Z n ( t) the number of nodes with no descendants at time t and let T n = β -1 nln( n/ln4)+(ln2)/(2 β). We prove that 2- n Z n ( T n + nτ), τ∈ℝ, converges to the Gompertz curve exp(-(ln2) e - βτ ). We also prove a central limit theorem for the martingale associated to Z n ( t).
Intrauterine growth curve in a low-income population in the outskirts of the city of São Paulo
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Julie Schlesinger
2005-12-01
Full Text Available Objective: To design an intrauterine growth curve of an Institutionthat serves the needy population of the city of Sao Paulo andcompare it to the intrauterine growth curves of the city of Denverand of the State of California which are considered classic in theliterature, and to verify whether the small-for-gestational-ageinfants classified by the different intrauterine growth curves presenta higher prevalence of birth asphyxia. Methods: Retrospectivestudy including data relative to weight, gestational age calculatedby the Capurro method, and 1 and 5-minute Apgar score, fromJune 2003 to December 2003, in a total of 1012 newborn infantsbetween 35 and 42 weeks of gestational age. The intrauterinegrowth curves were designed with data imported from the EPI-Info6.0™ software. The 10th, 50th and 90th percentiles of birth weight foreach gestational age as from the 35th week were calculated, andthe asphyxiated newborns among the small for gestational agewere compared with the group formed by the appropriate and thelarge for gestational age classified by the different curves. The chisquare test was used and p values < 0.05 were consideredsignificant. Results: The intrauterine growth curve of the Institutionwas narrower than that of Denver. When compared to the Californiacurve, we verified that the infants were classified as small-forgestational-age and large-for-gestational-age with lower values.Using Denver, the Institution, and California curves 2.9%, 9.5%, and19.9% of the infants were classified as small-for-gestational-age,respectively. Conclusions: The values obtained for the Institutioncurves were different from those of Denver and California curves. Alarger number of asphyxiated infants was found among the smallfor gestational age classified by the Denver intrauterine growthcurve than among those classified by the other two curves.
Ho, Kwok M
2017-08-31
Area under a receiver-operating-characteristic (AUROC) curve is widely used in medicine to summarize the ability of a continuous predictive marker to predict a binary outcome. This study illustrated how a U-shaped or inverted U-shaped continuous predictor would affect the shape and magnitude of its AUROC curve in predicting a binary outcome by comparing the ROC curves of the worst first 24-hour arterial pH values of 9549 consecutive critically ill patients in predicting hospital mortality before and after centering the predictor by its mean or median. A simulation dataset with an inverted U-shaped predictor was used to assess how this would affect the shape and magnitude of the AUROC curve. An asymmetrical U-shaped relationship between pH and hospital mortality, resulting in an inverse-sigmoidal ROC curve, was observed. The AUROC substantially increased after centering the predictor by its mean (0.611 vs 0.722, difference = 0.111, 95% confidence interval [CI] 0.087-0.135), and was further improved after centering by its median (0.611 vs 0.745, difference = 0.133, 95%CI 0.110-0.157). A sigmoidal-shaped ROC curve was observed for an inverted U-shaped predictor. In summary, a non-linear predictor can result in a biphasic-shaped ROC curve; and centering the predictor can reduce its bias towards null predictive ability.
Warschausky, S; Kay, J B; Kewman, D G
2001-03-01
To examine the recovery of aspects of functional independence as a continuous process using growth curve analysis. Retrospective database review of functional outcome assessment data from inception cohort. Inpatient rehabilitation unit; community. A total of 142 subjects (79.6% men; age range, 18-77yr; mean age +/- standard deviation, 36.2 +/- 15.5yr) who were admitted to a rehabilitation unit between March 1986 and November 1994 with a minimum of 4 postinjury FIM assessments. Neurologic subgroups included 63 individuals with paraplegia, 36 with low tetraplegia, 24 with high tetraplegia, and 19 with incomplete injury. FIM instrument. Growth curve analyses with hierarchical linear modeling using a decelerating recovery function yielded a reliable model in which longer rehabilitation length of stay was associated with a more rapid rate of recovery but lower plateau. Neurologic injury category had expected effects on rate and degree of recovery. Level of impairment-specific results included an age effect in which older age was associated with lower level of plateau. In specific neurologic groups there was a significant gender effect, in which men made more rapid recovery than women, and a significant effect of level of education, in which higher education was associated with more rapid rate of recovery. Rate of FIM recovery was reliably modeled in the sample with incomplete injuries, but none of the demographic predictors was significant. Functional recovery can be modeled as a decelerating rather than simple linear function. The study of predictors of recovery characteristics, including rate of recovery and plateau, offers a valuable way of understanding rehabilitative needs and outcomes. Gender and education effects on the recovery process are intriguing and warrant further investigation.
Golosovsky, Michael
2013-01-01
We discuss microscopic mechanisms of complex network growth, with the special emphasis of how these mechanisms can be evaluated from the measurements on real networks. As an example we consider the network of citations to scientific papers. Contrary to common belief that its growth is determined by the linear preferential attachment, our microscopic measurements show that it is driven by the nonlinear autocatalytic growth. This invalidates the scale-free hypothesis for the citation network. The nonlinearity is responsible for a dramatic dynamical phase transition: while the citation lifetime of majority of papers is 6-10 years, the highly-cited papers have practically infinite lifetime.
Golosovsky, Michael; Solomon, Sorin
2013-04-01
We discuss microscopic mechanisms of complex network growth, with the special emphasis of how these mechanisms can be evaluated from the measurements on real networks. As an example we consider the network of citations to scientific papers. Contrary to common belief that its growth is determined by the linear preferential attachment, our microscopic measurements show that it is driven by the nonlinear autocatalytic growth. This invalidates the scale-free hypothesis for the citation network. The nonlinearity is responsible for a dramatic dynamical phase transition: while the citation lifetime of majority of papers is 6-10 years, the highly-cited papers have practically infinite lifetime.
Energy Technology Data Exchange (ETDEWEB)
Roca Jusmet, J.; Padilla Rosa, E.
2004-07-01
From the beginning of the 90s the analysis of the relationships between economic growth and environmental pressures has been influenced by the Environmental Kuznets Curve hypothesis or inverted-U shaped relationship between environmental pressure and per capita income. Following this hypothesis, once achieved certain income level, more economic growth is followed by environmental quality improvement. In this paper, we analyse and discuss the theories that support this hypothesis as well as the empirical evidence on this subject. Further on we analyse the relationship between per capita income and the main environmental pollutants for the case does not support the hypothesis. The empirical evidence shows that economic growth, by itself, does not entail a pollution reduction. (Author) 35 refs.
Efficent Estimation of the Non-linear Volatility and Growth Model
2009-01-01
Ramey and Ramey (1995) introduced a non-linear model relating volatility to growth. The solution of this model by generalised computer algorithms for non-linear maximum likelihood estimation encounters the usual difficulties and is, at best, tedious. We propose an algebraic solution for the model that provides fully efficient estimators and is elementary to implement as a standard ordinary least squares procedure. This eliminates issues such as the ‘guesstimation’ of initial values and mul...
Xing, James Z; Gabos, Stephan; Huang, Biao; Pan, Tianhong; Huang, Min; Chen, Jie
2012-10-01
The mutation rate in cells induced by environmental genotoxic hazards is very low and difficult to detect using traditional cell counting assays. The established genetic toxicity tests currently recognized by regulatory authorities, such as conventional Ames and hypoxanthine guanine phosphoribosyl-transferase (HPRT) assays, are not well suited for higher-throughput screening as they require large amounts of test compounds and are very time consuming. In this study, we developed a novel cell-based assay for quantitative analysis of low numbers of cell copies with HPRT mutation induced by an environmental mutagen. The HPRT gene mutant cells induced by the mutagen were selected by 6-thioguanine (6-TG) and the cell's kinetic growth curve monitored by a real-time cell electronic sensor (RT-CES) system. When a threshold is set at a certain cell index (CI) level, samples with different initial mutant cell copies take different amounts of time in order for their growth (or CI accumulation) to cross this threshold. The more cells that are initially seeded in the test well, the faster the cell accumulation and therefore the shorter the time required to cross this threshold. Therefore, the culture time period required to cross the threshold of each sample corresponds to the original number of cells in the sample. A mutant cell growth time threshold (MT) value of each sample can be calculated to predict the number of original mutant cells. For mutagenesis determination, the RT-CES assay displayed an equal sensitivity (p > 0.05) and coefficients of variation values with good correlation to conventional HPRT mutagenic assays. Most importantly, the RT-CES mutation assay has a higher throughput than conventional cellular assays.
Frazier, D. O.; Penn, B. G.; Witherow, W. K.; Paley, M. S.
1991-01-01
Research on the growth of second- and third-order nonlinear optical (NLO) organic thin film by vapor deposition is reviewed. Particular attention is given to the experimental methods for growing thin films of p-chlorophenylurea, diacetylenes, and phthalocyanines; characteristics of the resulting films; and approaches for advancing thin film technology. It is concluded that the growth of NLO thin films by vapor processes is a promising method for the fabrication of planar waveguides for nonlinear optical devices. Two innovative approaches are proposed including a method of controlling the input beam frequency to maximize nonlinear effects in thin films and single crystals, and the alternate approach to the molecular design of organic NLO materials by increasing the transition dipole moment between ground and excited states of the molecule.
Non-linear Plasma Wake Growth of Electron Holes
Hutchinson, I H; Zhou, C
2015-01-01
An object's wake in a plasma with small Debye length that drifts \\emph{across} the magnetic field is subject to electrostatic electron instabilities. Such situations include, for example, the moon in the solar wind wake and probes in magnetized laboratory plasmas. The instability drive mechanism can equivalently be considered drift down the potential-energy gradient or drift up the density-gradient. The gradients arise because the plasma wake has a region of depressed density and electrostatic potential into which ions are attracted along the field. The non-linear consequences of the instability are analysed in this paper. At physical ratios of electron to ion mass, neither linear nor quasilinear treatment can explain the observation of large-amplitude perturbations that disrupt the ion streams well before they become ion-ion unstable. We show here, however, that electron holes, once formed, continue to grow, driven by the drift mechanism, and if they remain in the wake may reach a maximum non-linearly stable...
Estimation of growth parameters using a nonlinear mixed Gompertz model.
Wang, Z; Zuidhof, M J
2004-06-01
In order to maximize the utility of simulation models for decision making, accurate estimation of growth parameters and associated variances is crucial. A mixed Gompertz growth model was used to account for between-bird variation and heterogeneous variance. The mixed model had several advantages over the fixed effects model. The mixed model partitioned BW variation into between- and within-bird variation, and the covariance structure assumed with the random effect accounted for part of the BW correlation across ages in the same individual. The amount of residual variance decreased by over 55% with the mixed model. The mixed model reduced estimation biases that resulted from selective sampling. For analysis of longitudinal growth data, the mixed effects growth model is recommended.
Directory of Open Access Journals (Sweden)
Wu Huaiqin
2009-01-01
Full Text Available This paper considers a new class of additive neural networks where the neuron activations are modelled by discontinuous functions with nonlinear growth. By Leray-Schauder alternative theorem in differential inclusion theory, matrix theory, and generalized Lyapunov approach, a general result is derived which ensures the existence and global asymptotical stability of a unique periodic solution for such neural networks. The obtained results can be applied to neural networks with a broad range of activation functions assuming neither boundedness nor monotonicity, and also show that Forti's conjecture for discontinuous neural networks with nonlinear growth activations is true.
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
It is practical, economic and sometimes essential to derive rules or conclusions by performing lesser runs of experiments. In this part, a methodology based on 2f factorial design was brought up to derive guidelines to simulate growth curve and production of sugars by Spirulina (Arthrospira) maxima. The growth curve or accumulation process of sugars was idealized by sets of straight lines limited by phase transfers of growth or accumulation of sugars. Normal analyses of the critical values of the transfers were used to derive their linear relationships with the initial conditions of the experimental factors. These linear functions were called guidelines and were used to simulate the growth curve or accumulation of sugars. Generalization of the guideline technique was determined by the kinetic limitation of nutrient nitrogen or sulfur that was dependent upon their stoichiometric deficiency directly derived from their initial values in the medium. This method uses the initial conditions of culture and does not need measurements of concentrations of nitrate, sulfate and pigments during cultivation. It is a practical and useful alternative way to trace and predict approximately the growth curve and production of sugars by S. maxima.
Directory of Open Access Journals (Sweden)
Martin Ricker
Full Text Available Growth curves are monotonically increasing functions that measure repeatedly the same subjects over time. The classical growth curve model in the statistical literature is the Generalized Multivariate Analysis of Variance (GMANOVA model. In order to model the tree trunk radius (r over time (t of trees on different sites, GMANOVA is combined here with the adapted PL regression model Q = A · T+E, where for b ≠ 0 : Q = Ei[-b · r]-Ei[-b · r1] and for b = 0 : Q = Ln[r/r1], A = initial relative growth to be estimated, T = t-t1, and E is an error term for each tree and time point. Furthermore, Ei[-b · r] = ∫(Exp[-b · r]/rdr, b = -1/TPR, with TPR being the turning point radius in a sigmoid curve, and r1 at t1 is an estimated calibrating time-radius point. Advantages of the approach are that growth rates can be compared among growth curves with different turning point radiuses and different starting points, hidden outliers are easily detectable, the method is statistically robust, and heteroscedasticity of the residuals among time points is allowed. The model was implemented with dendrochronological data of 235 Pinus montezumae trees on ten Mexican volcano sites to calculate comparison intervals for the estimated initial relative growth A. One site (at the Popocatépetl volcano stood out, with A being 3.9 times the value of the site with the slowest-growing trees. Calculating variance components for the initial relative growth, 34% of the growth variation was found among sites, 31% among trees, and 35% over time. Without the Popocatépetl site, the numbers changed to 7%, 42%, and 51%. Further explanation of differences in growth would need to focus on factors that vary within sites and over time.
Ricker, Martin; Peña Ramírez, Víctor M; von Rosen, Dietrich
2014-01-01
Growth curves are monotonically increasing functions that measure repeatedly the same subjects over time. The classical growth curve model in the statistical literature is the Generalized Multivariate Analysis of Variance (GMANOVA) model. In order to model the tree trunk radius (r) over time (t) of trees on different sites, GMANOVA is combined here with the adapted PL regression model Q = A · T+E, where for b ≠ 0 : Q = Ei[-b · r]-Ei[-b · r1] and for b = 0 : Q = Ln[r/r1], A = initial relative growth to be estimated, T = t-t1, and E is an error term for each tree and time point. Furthermore, Ei[-b · r] = ∫(Exp[-b · r]/r)dr, b = -1/TPR, with TPR being the turning point radius in a sigmoid curve, and r1 at t1 is an estimated calibrating time-radius point. Advantages of the approach are that growth rates can be compared among growth curves with different turning point radiuses and different starting points, hidden outliers are easily detectable, the method is statistically robust, and heteroscedasticity of the residuals among time points is allowed. The model was implemented with dendrochronological data of 235 Pinus montezumae trees on ten Mexican volcano sites to calculate comparison intervals for the estimated initial relative growth A. One site (at the Popocatépetl volcano) stood out, with A being 3.9 times the value of the site with the slowest-growing trees. Calculating variance components for the initial relative growth, 34% of the growth variation was found among sites, 31% among trees, and 35% over time. Without the Popocatépetl site, the numbers changed to 7%, 42%, and 51%. Further explanation of differences in growth would need to focus on factors that vary within sites and over time.
[Branch growth of Korean pine plantation based on nonlinear mixed model].
Wang, Chun-Hong; Li, Feng-Ri; Jia, Wei-Wei; Dong, Li-Hu
2013-07-01
Based on the branch analysis data from 36 sample trees in a Korean pine plantation in Mengjiagang Forest Farm of Heilongjiang Province, Northeast China, and by using Mitcherlich and Richards equations as the models of branch diameter and branch length growth, respectively, the effects of sampling plot and sample tree were investigated, and the nonlinear mixed models of branch diameter and branch length growth were established by the PROC NLMIXED procedure of SAS software. The evaluation statistics such as Akaike information criterion (AIC), Bayesian information criterion (BIC), -2Log likelihood, and likelihood ratio test (LRT) were used to compare the prediction precisions of the models. When considering plot effect, and taking alpha1 and alpha3 and beta1 and beta3 as the random parameters, respectively, the models of branch diameter and branch length growth had the best performance. When considering tree effect, and taking alpha2 and alpha3 and beta2 and beta3 as the random parameters, respectively, the models of branch diameter and branch length growth had the best performance. The nonlinear mixed model could not only reflect the mean variation of branch growth, but also show the differences among the individual trees. No matter considering plot effect or tree effect, the fitting precision of the nonlinear mixed model was better than that of the ordinary regression analysis model. Moreover, the fitting precision of the nonlinear mixed model was better when considering tree effect than considering plot effect.
Millan Núñez-Cortés, Jesús; Alvarez Rodriguez, Ysmael; Alvarez Novés, Granada; Recarte Garcia-Andrade, Carlos; Alvarez-Sala Walther, Luis
2014-01-01
HMG-CoA-Reductase inhibitors, also known as statins, are currently the most powerful cholesterol-lowering drugs available on the market. Clinical trials and experimental evidence suggest that statins have heavy anti-atherosclerotic effects. These are in part consequence of lipid lowering but also result from pleiotropic actions of the drugs. These so-called pleiotropic properties affect various aspects of cell function, inflammation, coagulation, and vasomotor activity. These effects are mediated either indirectly through LDL-c reduction or via a direct effect on cellular functions. Although many of the pleiotropic properties of statins may be a class effect, some may be unique to certain agents and account for differences in their pharmacological activity. So, although statins typically have similar effects on LDL-c levels, differences in chemical structure and pharmacokinetic profile can lead to variations in pleiotropic effects. In this paper we analize the in vitro effects of different statins over different cell lines from cells implicated in atherosclerotic process: endothelial cells, fibroblasts, and vascular muscular cells. In relation with our results we can proof that the effects of different dosis of different statins provides singular effects over growth curves of different cellular lines, a despite of a class-dependent effects. So, pleiotropic effects and its reversibility with mevalonate are different according with the molecule and the dosis. Copyright © 2013 Elsevier España, S.L. y SEA. All rights reserved.
Chen, Ya-Mei; Chen, Duan-Rung; Chiang, Tung-Liang; Tu, Yu-Kang; Yu, Hsiao-Wei
2016-01-01
Our aim was to identify disablement factors, including predisposing, intra-individual, and extra-individual factors, which predict the rate of change in general functional disability (GFD) in older adults. This study utilized the Taiwan Longitudinal Study on Aging Survey in 1996-2007 (N=3,186). Multiple-indicator latent growth curve modeling was used to examine how 12 disablement factors predicted the rate of change in GFD. GFD trajectories were modeled using Nagi's functional limitations, activities of daily living, and instrumental activities of daily living. Greater age (B=.025), female gender (B=.114), and greater numbers of comorbidities (B=.038) were associated with faster increase in GFD. Education (B=-.005) and participation in physically active leisure time activities (B=-.031) were associated with slower increase in GFD. Our findings add to the understanding of how disablement factors contribute to the rate of change in GFD. Predisposing factors played the main role. However, the factors we found to be associated with the rate of change in GFD in older adults were slightly different from the factors reported in the literature. Decreasing the number of comorbidities and increasing the level of physically active leisure time activity should be considered priorities for preventing disability as people age.
Nonlinearities in Inflation and Growth Nexus: The Case of Tanzania
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Manamba EPAPHRA
2016-09-01
Full Text Available Abstract. Achieving high economic growth rate while maintaining low inflation rate, has become the main objective of monetary authorities all over the world. Indeed, empirical literature reflects that high inflation rates are detrimental to long run growth and entail welfare costs. To achieve this objective, central banks have availed different options from time to time which include inflation targeting. Monetary authorities in Tanzania have been targeting an inflation level of around 5 percent per annum for economic policy purposes. However, when high inflation is to be controlled, tight monetary policy is put in place which might in turn affect the economic activity. Also, the Tobin effect suggests that inflation causes individuals to substitute out of money and into interest earning assets, which leads to greater capital intensity which in turn promotes economic growth. Against these major points, this paper examines a non linear relationship between inflation and economic growth using both a quadratic and threshold endogenous models and attempts to identify the existence of threshold effects between these variables. The paper uses a data set spanning from 1967 to 2015. The most interesting finding of the estimations is that the estimated coefficient of the linear term of inflation is negative while the estimated coefficient of the square term of inflation is positive, suggesting a U-shaped effect as opposed to inverse or inverted U-shaped relationship found in other countries by previous studies. These results suggest that the Tobin effect may be valid for high inflation, in which people strongly realize the importance of substituting money for interest-bearing assets. This leads to an increase in capital investment, and in turn, an increase in economic growth even with high inflation rate. However, this U-shaped relationship between inflation and economic growth suggests that, the economy is better off at extremely low inflation episodes
Hu, Y. J.; Yang, J.; Kitipornchai, S.
2013-07-01
This paper presents a geometrically nonlinear micro-beam model for the electro-dynamic analysis of an initially curved micro-beam under an applied voltage, with an emphasis on its snap-through and pull-in behaviors. The governing equations of motion and the associated boundary conditions are derived in an arc coordinate system without involving any assumptions on the nonlinear deformation. Differential quadrature method (DQM) and Petzold-Gear Backward Differentiation Formulas (BDF) are employed to solve the governing equations in the space and time domains respectively to obtain the nonlinear fundamental frequency, snap-through voltage, pull-in voltage and the corresponding mode shapes of a micro-beam clamped at both ends. The present analysis is validated through a direct comparison with the published experimental and numerical results. A parametric study is conducted to investigate the influences of the initial gap, base length, arc rise, and initial curved configuration on the snap-through and pull-in behaviors of the micro-beam.
Directory of Open Access Journals (Sweden)
Wagner C Valenti
1994-01-01
Full Text Available In this paper, female Macrobrachium carcinus (Linnaeus, 1758 maturation curve, weight/length relationship, length and weight growth curves were studied. Prawns were captured, by traps, in Ribeira de Iguape river (24ºS and 47ºW, southern Brazil. There were used 207 females. It was observed that M. carcinus presents several spawnings during its life cycle and reproductive period goes on, at least till six years old. Weight/length relationship can be represented for the equation W = 8.73 E-3 L3.28. Expressions obtained for length and weight growth curves are Lt = 21 .0 (1-e-0493t and Wt= 190 (1-e-0493t3.28. respectively. A symptotic maximum length and asymptotic maximum weight are nearly attained at six and eight years old, respectively.
Energy Technology Data Exchange (ETDEWEB)
Chiou-Wei, Song Zan [Department of Managerial Economics, Nan-Hua University, Chia-Yi (China); Chen, Ching-Fu [Department of Transportation and Communication Management Science, National Cheng Kung University, 1, Ta-Hsueh Road, Tainan, 701 (China); Zhu, Zhen [Department of Economics, College of Business, University of Central Oklahoma, Edmon, OK, 43034 (United States)
2008-11-15
The relationship between energy consumption and economic growth is considered as an imperative issue in energy economics. Previous studies have ignored the nonlinear behavior which could be caused by structural breaks. In this study, both linear and nonlinear Granger causality tests are applied to examine the causal relationship between energy consumption and economic growth for a sample of Asian newly industrialized countries as well as the U.S. This study finds evidence supporting a neutrality hypothesis for the United States, Thailand, and South Korea. However, empirical evidence on Philippines and Singapore reveals a unidirectional causality running from economic growth to energy consumption while energy consumption may have affected economic growth for Taiwan, Hong Kong, Malaysia and Indonesia. Policy implications are also discussed. (author)
Li, Fuzhong; Duncan, Terry E.; Duncan, Susan C.; McAuley, Edward; Chaumeton, Nigel R.; Harmer, Peter
2001-01-01
Examined whether a Tai Chi exercise program enhanced the psychological well-being of 98 elderly individuals. Analyzed repeated measures data about participants using latent growth curve analysis. Results indicate the beneficial effects of participation in the Tai Chi program. Discusses implications related to the exercise-psychological health…
Palardy, Gregory J.
2008-01-01
This study uses large-scale survey data and a multiple group, multilevel latent growth curve model to examine differential school effects between low, middle, and high social class composition public schools. The results show that the effects of school inputs and school practices on learning differ across the 3 subpopulations. Moreover, student…
Palardy, Gregory J.
2008-01-01
This study uses large-scale survey data and a multiple group, multilevel latent growth curve model to examine differential school effects between low, middle, and high social class composition public schools. The results show that the effects of school inputs and school practices on learning differ across the 3 subpopulations. Moreover, student…
Greene, Melissa L.; Way, Niobe
2005-01-01
The current study presents a growth curve analysis of self-esteem among Black, Latino, and Asian American high school students. A series of hierarchical linear models were used to examine patterns and predictors of change in self-esteem over time. Results revealed an average increase in self-esteem with age. Although boys and girls experienced…
Saengprom, Narumon; Erawan, Waraporn; Damrongpanit, Suntonrapot; Sakulku, Jaruwan
2015-01-01
The purposes of this study were 1) Compare analytical thinking ability by testing the same sets of students 5 times 2) Develop and verify whether analytical thinking ability of students corresponds to second-order growth curve factors model. Samples were 1,093 eighth-grade students. The results revealed that 1) Analytical thinking ability scores…
Li, Fuzhong; Duncan, Terry E.; Duncan, Susan C.; McAuley, Edward; Chaumeton, Nigel R.; Harmer, Peter
2001-01-01
Examined whether a Tai Chi exercise program enhanced the psychological well-being of 98 elderly individuals. Analyzed repeated measures data about participants using latent growth curve analysis. Results indicate the beneficial effects of participation in the Tai Chi program. Discusses implications related to the exercise-psychological health…
Greene, Melissa L.; Way, Niobe
2005-01-01
The current study presents a growth curve analysis of self-esteem among Black, Latino, and Asian American high school students. A series of hierarchical linear models were used to examine patterns and predictors of change in self-esteem over time. Results revealed an average increase in self-esteem with age. Although boys and girls experienced…
Saengprom, Narumon; Erawan, Waraporn; Damrongpanit, Suntonrapot; Sakulku, Jaruwan
2015-01-01
The purposes of this study were 1) Compare analytical thinking ability by testing the same sets of students 5 times 2) Develop and verify whether analytical thinking ability of students corresponds to second-order growth curve factors model. Samples were 1,093 eighth-grade students. The results revealed that 1) Analytical thinking ability scores…
The Non-Linear Effect of Corporate Taxes on Economic Growth
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Huňady Ján
2015-03-01
Full Text Available The paper deals with the problem of taxation and its potential impact on economic growth and presents some new empirical insights into this topic. The main aim of the paper is to verify an assumed nonlinear impact of corporate tax rates on economic growth. Based on the theory of public finance and taxation, we hypothesize that at relatively low tax rates it is possible that the impact of taxation on economic growth become slightly positive. On the other hand when the tax rates are higher a negative impact of taxation on economic growth could be expected. Despite the fact that the most of the existing studies find a negative linear relationship between these variables, we can also find strong support for a non-linear relationship from several theoretical models as well as some empirical studies. Based on panel data fixed-effects econometric models, we, as well, find empirical evidence for a non-linear relationship between nominal and effective corporate tax rates and economic growth. Our data consists of annual observations for the period 1999 to 2011 for EU Member States. Based on the results, we also estimated the optimal level of the corporate tax rate in terms of maximizing economic growth in the average of the EU countries.
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Andrew Phiri
2016-03-01
Full Text Available NorthWest University, South Africa Abstract: Tourism is increasingly being recognized as an essential component of economic growth in South Africa. The purpose of this study is to examine cointegration and causal effects between tourism and economic growth in South Africa for annual data collected between 1995 and 2014. To this end, the paper contrasts two empirical approaches; (1 Engle and Granger (1987 linear cointegration framework, and (2 Enders and Granger (1998 nonlinear cointegration framework. Furthermore, two empirical measures of tourism development are used in the study, namely; tourist receipts and number of international tourist arrivals. The empirical results of the linear framework supports the tourism-led growth hypothesis when tourist receipts are used as a measure of tourismdevelopment.However, the nonlinear framework depicts bi-directional causality between tourist receipts and economic growth. Also, the linear framework supports the economic growth-driven-tourism-hypothesis for tourist arrivals whereas the nonlinear framework depicts no causality between tourist arrivals and economic growth.
2015-03-01
AFRL-RY-WP-TP-2015-0068 GROWTH AND STUDY OF NONLINEAR OPTICAL MATERIALS FOR FREQUENCY CONVERSION DEVICES WITH APPLICATIONS IN DEFENCE AND...2015 Technical Paper 1 August 2013 – 1 August 2014 4. TITLE AND SUBTITLE GROWTH AND STUDY OF NONLINEAR OPTICAL MATERIALS FOR FREQUENCY CONVERSION...SUBJECT TERMS hydride vapor phase epitaxy, nonlinear optical materials , quasi-phase matching 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF
Non-linear pattern formation in bone growth and architecture.
Salmon, Phil
2014-01-01
The three-dimensional morphology of bone arises through adaptation to its required engineering performance. Genetically and adaptively bone travels along a complex spatiotemporal trajectory to acquire optimal architecture. On a cellular, micro-anatomical scale, what mechanisms coordinate the activity of osteoblasts and osteoclasts to produce complex and efficient bone architectures? One mechanism is examined here - chaotic non-linear pattern formation (NPF) - which underlies in a unifying way natural structures as disparate as trabecular bone, swarms of birds flying, island formation, fluid turbulence, and others. At the heart of NPF is the fact that simple rules operating between interacting elements, and Turing-like interaction between global and local signals, lead to complex and structured patterns. The study of "group intelligence" exhibited by swarming birds or shoaling fish has led to an embodiment of NPF called "particle swarm optimization" (PSO). This theoretical model could be applicable to the behavior of osteoblasts, osteoclasts, and osteocytes, seeing them operating "socially" in response simultaneously to both global and local signals (endocrine, cytokine, mechanical), resulting in their clustered activity at formation and resorption sites. This represents problem-solving by social intelligence, and could potentially add further realism to in silico computer simulation of bone modeling. What insights has NPF provided to bone biology? One example concerns the genetic disorder juvenile Pagets disease or idiopathic hyperphosphatasia, where the anomalous parallel trabecular architecture characteristic of this pathology is consistent with an NPF paradigm by analogy with known experimental NPF systems. Here, coupling or "feedback" between osteoblasts and osteoclasts is the critical element. This NPF paradigm implies a profound link between bone regulation and its architecture: in bone the architecture is the regulation. The former is the emergent
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Veldhuizen Albert G
2010-05-01
Full Text Available Abstract Background Scoliosis is present in 3-5% of the children in the adolescent age group, with a higher incidence in females. Treatment of adolescent idiopathic scoliosis is mainly dependent on the progression of the scoliotic curve. There is a close relationship between curve progression and rapid (spinal growth of the patient during puberty. However, until present time no conclusive method was found for predicting the timing and magnitude of the pubertal growth spurt in total body height, or the curve progression of the idiopathic scoliosis. The goal of this study is to determine the predictive value of several maturity indicators that reflect growth or remaining growth potential, in order to predict timing of the peak growth velocity of total body height in the individual patient with adolescent idiopathic scoliosis. Furthermore, different parameters are evaluated for their correlation with curve progression in the individual scoliosis patient. Methods/design This prospective, longitudinal cohort study will be incorporated in the usual care of patients with adolescent idiopathic scoliosis. All new patients between 8 and 17 years with adolescent idiopathic scoliosis (Cobb angle >10 degrees visiting the outpatient clinic of the University Medical Center Groningen are included in this study. Follow up will take place every 6 months. The present study will use a new ultra-low dose X-ray system which can make total body X-rays. Several maturity indicators are evaluated like different body length dimensions, secondary sexual characteristics, skeletal age in hand and wrist, skeletal age in the elbow, the Risser sign, the status of the triradiate cartilage, and EMG ratios of the paraspinal muscle activity. Correlations of all dimensions will be calculated in relationship to the timing of the pubertal growth spurt, and to the progression of the scoliotic curve. An algorithm will be made for the optimal treatment strategy in the individual patient
Curve of growth methodology applied to laser-induced plasma emission spectroscopy
Gornushkin, I. B.; Anzano, J. M.; King, L. A.; Smith, B. W.; Omenetto, N.; Winefordner, J. D.
1999-04-01
The curve-of-growth (COG) method was applied to a laser-induced plasma. The plasma was produced by a Nd:YAG laser on the surface of steel samples containing 0.007-1.3% of Cr. The emission was collected from the top of the plasma by means of a 45° pierced mirror and aligned onto an intensified charge-coupled device (ICCD) with a gate width of 1 μs and a variable delay time. The resonance 425.4 nm Cr line was used for construction of the COG. The temperature of the plasma (˜8000 K at 5-μs delay) was determined from a Boltzmann plot. The damping constant a, proportional to the ratio of the Lorentzian to the Doppler line widths, was found from the best fit of a series of calculated COG to the experimental data points and was 0.20±0.05. The number density of neutral Cr atoms which corresponded to the transition between low and high optical densities, was ≈6.5·10 12 cm -3. The cross-section for broadening collisions of Cr atoms with atmospheric species (presumably N 2) was calculated to be (66±16) Å. The shape of the 425.4-nm Cr line was additionally checked by scanning an ultra-narrow cw Ti:Sapphire laser across the atomic transition and found to be in agreement with preliminary estimates. The potential of the COG method for laser breakdown spectroscopy is discussed.
Indian Academy of Sciences (India)
K. Karami; R. Mohebi
2007-12-01
We use the method introduced by Karami & Mohebi (2007), and Karami & Teimoorinia (2007) which enable us to derive the orbital parameters of the spectroscopic binary stars by the nonlinear least squares of observed . curve fitting (o–c). Using the measured experimental data for radial velocities of the four double-lined spectroscopic binary systems PV Pup, HD 141929, EE Cet and V921 Her, we find both the orbital and the combined spectroscopic elements of these systems. Our numerical results are in good agreement with those obtained using the method of Lehmann-Filhés.
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Jorge Luis Ferreira
2011-09-01
.80kg and 0.004 dia-1; 337.60kg and 0.005 dia-1; and 309.60kg and 0,008 dia-1 for Brody, Von Bertalanffy, Gompertz and Logistic nonlinear models, respectively. The data adjustment for weight-age of the animal provides information describing the growth curve and the future prognostic for animals managed under the same environmental situation. The properties of four nonlinear models were discussed concerning its applications in the fitting of growth curves in Nellore cattle production. In the period analyzed, Von Bertalanffy nonlinear model was indicated to estimate the body weight of Nellore cattle from Northern Brazil.
Energy Technology Data Exchange (ETDEWEB)
Chen, Xiang [ORNL; Nanstad, Randy K [ORNL; Sokolov, Mikhail A [ORNL
2014-01-01
The direct current potential drop (DCPD) technique has been applied to derive the J-integral vs. crack growth resistance curve (J-R curve) for fracture toughness characterization of structural materials. The test matrix covered three materials including type 316LN stainless steels, Ni-based alloy 617, and one ferritic-martensitic steel, three specimen configurations including standard compact, single edge bending, and disk-shaped compact specimens, and temperatures ranging from 20 C to 650 C. When compared with baseline J-R curves derived from the ASTM normalization method, the original J-R curves from the DCPD technique yielded much smaller Jq values due to the influence of crack blunting, plastic deformation, etc. on potential drop. To counter these effects, a new procedure for adjusting DCPD J-R curves was proposed. After applying the new adjustment procedure, the average difference in Jq between the DCPD technique and the normalization method was only 5.2% and the difference in tearing modulus was 7.4%. The promising result demonstrates the applicability of the DCPD technique for the J-R curve characterization especially in extreme environments, such as elevated temperatures, where the conventional elastic unloading compliance method faces considerable challenges.
Campani, Marco
2014-01-01
The empirical and theoretical justification of Gartner hype curves is a very relevant open question in the field of Technological Life Cycle analysis. The scope of the present paper is to introduce a simple model describing the growth of scientific/technological research impact, in the specific case where science is the main source of a new idea driving a technological development, leading to hype-type evolution curves. The main idea of the model is that, in a first stage, the growth of the scientific interest of a new specific field (as can be measured by publication numbers) basically follows the classical logistic growth curve. At a second stage, starting at a later trigger time, the technological development based on that scientific idea (as can be measured by patent deposits) can be described as the integral (in a mathematical sense) of the first curve, since technology is based on the overall accumulated scientific knowledge. The model is tested through a bibliometric analysis of the publication and pat...
Valenti,Wagner C; Jeanette de T.C. de Mello; Vera L Lobão
1994-01-01
In this paper, female Macrobrachium carcinus (Linnaeus, 1758) maturation curve, weight/length relationship, length and weight growth curves were studied. Prawns were captured, by traps, in Ribeira de Iguape river (24ºS and 47ºW), southern Brazil. There were used 207 females. It was observed that M. carcinus presents several spawnings during its life cycle and reproductive period goes on, at least till six years old. Weight/length relationship can be represented for the equation W = 8.73 E-3 L...
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Hyun-Seob Song
2013-09-01
Full Text Available The nonlinear behavior of metabolic systems can arise from at least two different sources. One comes from the nonlinear kinetics of chemical reactions in metabolism and the other from nonlinearity associated with regulatory processes. Consequently, organisms at a constant growth rate (as experienced in a chemostat could display multiple metabolic states or display complex oscillatory behavior both with potentially serious implications to process operation. This paper explores the nonlinear behavior of a metabolic model of Escherichia coli growth on mixed substrates with sufficient detail to include regulatory features through the cybernetic postulate that metabolic regulation is the consequence of a dynamic objective function ensuring the organism’s survival. The chief source of nonlinearity arises from the optimal formulation with the metabolic state determined by a convex combination of reactions contributing to the objective function. The model for anaerobic growth of E. coli was previously examined for multiple steady states in a chemostat fed by a mixture of glucose and pyruvate substrates under very specific conditions and experimentally verified. In this article, we explore the foregoing model for nonlinear behavior over the full range of parameters, γ (the fractional concentration of glucose in the feed mixture and D (the dilution rate. The observed multiplicity is in the cybernetic variables combining elementary modes. The results show steady-state multiplicity up to seven. No Hopf bifurcation was encountered, however. Bifurcation analysis of cybernetic models is complicated by the non-differentiability of the cybernetic variables for enzyme activities. A methodology is adopted here to overcome this problem, which is applicable to more complicated metabolic networks.
Indian Academy of Sciences (India)
S Gunasekaran; G Anand; R Arun Balaji; J Dhanalakshmi; S Kumaresan
2010-10-01
Single crystals of urea thiourea mercuric sulphate (UTHS) and urea thiourea mercuric chloride (UTHC), semi-organic nonlinear optical materials, were grown by low-temperature solution growth technique by slow evaporation method using water as the solvent. Good quality single crystals were grown within three weeks. The nonlinear nature of the crystals was confirmed by SHG test. The UV–Vis spectrum showed the transmitting ability of the crystals in the entire visible region. FTIR spectrum was recorded and vibrational assignments were made. The degree of dopant inclusion was ascertained by AAS. The TGA–DTA studies showed the thermal properties of the crystals.
A method to measure the nonlinear force caused emittance growth in a RF photoinjector
Institute of Scientific and Technical Information of China (English)
Li Zheng-Hong; Yang Zhen-Ping
2006-01-01
Based on the multi-slit method, a new method is introduced to measure the non linear force caused emittance growth in a RF photoinjector. It is possible to reconstruct the phase space of a beam under some conditions by the multi-slit method. Based on the reconstructed phase space, besides the emittance, the emittance growth from the distortion of the phase space can also be measured. The emittance growth results from the effects of nonlinear force acting on electron, which is very important for the high quality beam in a RF photoinjector.
Mamatsashvili, George; Dong, Siwei; Khujadze, George; Chagelishvili, George; Jiménez, Javier; Foysi, Holger
2016-04-01
We performed direct numerical simulations of homogeneous shear turbulence to study the mechanism of the self-sustenance of subcritical turbulence in spectrally stable (constant) shear flows. For this purpose, we analyzed the turbulence dynamics in Fourier/wavenumber/spectral space based on the simulation data for the domain aspect ratio 1 : 1 : 1. Specifically, we examined the interplay of linear transient growth of Fourier harmonics and nonlinear processes. The transient growth of harmonics is strongly anisotropic in spectral space. This, in turn, leads to anisotropy of nonlinear processes in spectral space and, as a result, the main nonlinear process appears to be not a direct/inverse, but rather a transverse/angular redistribution of harmonics in Fourier space referred to as the nonlinear transverse cascade. It is demonstrated that the turbulence is sustained by the interplay of the linear transient, or nonmodal growth and the transverse cascade. This course of events reliably exemplifies the wellknown bypass scenario of subcritical turbulence in spectrally stable shear flows. These processes mainly operate at large length scales, comparable to the box size. Consequently, the central, small wavenumber area of Fourier space (the size of which is determined below) is crucial in the self-sustenance and is labeled the vital area. Outside the vital area, the transient growth and the transverse cascade are of secondary importance - Fourier harmonics are transferred to dissipative scales by the nonlinear direct cascade. The number of harmonics actively participating in the self-sustaining process (i.e., the harmonics whose energies grow more than 10% of the maximum spectral energy at least once during evolution) is quite large - it is equal to 36 for the considered box aspect ratio - and obviously cannot be described by low-order models.
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Xavier João B
2011-06-01
Full Text Available Abstract Background Online spectrophotometric measurements allow monitoring dynamic biological processes with high-time resolution. Contrastingly, numerous other methods require laborious treatment of samples and can only be carried out offline. Integrating both types of measurement would allow analyzing biological processes more comprehensively. A typical example of this problem is acquiring quantitative data on rhamnolipid secretion by the opportunistic pathogen Pseudomonas aeruginosa. P. aeruginosa cell growth can be measured by optical density (OD600 and gene expression can be measured using reporter fusions with a fluorescent protein, allowing high time resolution monitoring. However, measuring the secreted rhamnolipid biosurfactants requires laborious sample processing, which makes this an offline measurement. Results Here, we propose a method to integrate growth curve data with endpoint measurements of secreted metabolites that is inspired by a model of exponential cell growth. If serial diluting an inoculum gives reproducible time series shifted in time, then time series of endpoint measurements can be reconstructed using calculated time shifts between dilutions. We illustrate the method using measured rhamnolipid secretion by P. aeruginosa as endpoint measurements and we integrate these measurements with high-resolution growth curves measured by OD600 and expression of rhamnolipid synthesis genes monitored using a reporter fusion. Two-fold serial dilution allowed integrating rhamnolipid measurements at a ~0.4 h-1 frequency with high-time resolved data measured at a 6 h-1 frequency. We show how this simple method can be used in combination with mutants lacking specific genes in the rhamnolipid synthesis or quorum sensing regulation to acquire rich dynamic data on P. aeruginosa virulence regulation. Additionally, the linear relation between the ratio of inocula and the time-shift between curves produces high-precision measurements of
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
We introduce a new method to derive the orbital parameters of spectroscopic binary stars by nonlinear least squares of (o - c). Using the measured radial velocity data of the four double lined spectroscopic binary systems,AI Phe,GM Dra,HD 93917 and V502 Oph,we derived both the orbital and combined spectroscopic elements of these systems.Our numerical results are in good agreement with the those obtained using the method of Lehmann-Filhés.
Liebowitz, H.; Jones, D. L.; Poulose, P. K.
1974-01-01
Because of the current high degree of interest in the development of a standard nonlinear test method, analytical and experimental comparisons have been made between the R-curve, COD, J-integral and nonlinear energy methods. A general definition of fracture toughness is proposed and the fundamental definitions of each method are compared to it. Experimental comparisons between the COD, J-integral, nonlinear energy and standard ASTM methods have been made for a series of compact tension tests on several aluminum alloys. Some of the tests were conducted according to the ASTM standard method E399-72, while the specimen thickness was reduced below the minimum requirement for plane strain fracture toughness testing for several other test series. The fracture toughness values obtained by the COD method were significantly higher than the toughness values obtained by the other three methods. All of the methods displayed a tendency to yield higher toughness values as the thickness was decreased below the ASTM plane strain requirement.
Nonlinear Dynamics and Analysis of Intracranial Saccular Aneurysms with Growth and Remodeling
Directory of Open Access Journals (Sweden)
Manal Badgaish
2016-01-01
Full Text Available A new mathematical model for the interaction of blood flow with the arterial wall surrounded by cerebral spinal fluid is developed with applications to intracranial saccular aneurysms. The blood pressure acting on the inner arterial wall is modeled via a Fourier series, the arterial wall is modeled as a spring-mass system incorporating growth and remodeling, and the surrounding cerebral spinal fluid is modeled via a simplified one-dimensional compressible Euler equation with inviscid flow and negligible nonlinear effects. The resulting nonlinear coupled fluid-structure interaction problem is analyzed and a perturbation technique is employed to derive the first-order approximation solution to the system. An analytical solution is also derived for the linearized version of the problem using Laplace transforms. The solutions are validated against related work from the literature and the results suggest the biological significance of the inclusion of the growth and remodeling effects on the rupture of intracranial aneurysms.
Yan, Xuehua
2014-01-01
This paper is the further investigation of work of Yan and Liu, 2011, and considers the global practical tracking problem by output feedback for a class of uncertain nonlinear systems with not only unmeasured states dependent growth but also time-varying time delay. Compared with the closely related works, the remarkableness of the paper is that the time-varying time delay and unmeasurable states are permitted in the system nonlinear growth. Motivated by the related tracking results and flexibly using the ideas and techniques of universal control and dead zone, an adaptive output-feedback tracking controller is explicitly designed with the help of a new Lyapunov-Krasovskii functional, to make the tracking error prescribed arbitrarily small after a finite time while keeping all the closed-loop signals bounded. A numerical example demonstrates the effectiveness of the results. PMID:25276859
Vuori, Kaarina; Strandén, Ismo; Sevón-Aimonen, Marja-Liisa; Mäntysaari, Esa A
2006-01-01
A method based on Taylor series expansion for estimation of location parameters and variance components of non-linear mixed effects models was considered. An attractive property of the method is the opportunity for an easily implemented algorithm. Estimation of non-linear mixed effects models can be done by common methods for linear mixed effects models, and thus existing programs can be used after small modifications. The applicability of this algorithm in animal breeding was studied with simulation using a Gompertz function growth model in pigs. Two growth data sets were analyzed: a full set containing observations from the entire growing period, and a truncated time trajectory set containing animals slaughtered prematurely, which is common in pig breeding. The results from the 50 simulation replicates with full data set indicate that the linearization approach was capable of estimating the original parameters satisfactorily. However, estimation of the parameters related to adult weight becomes unstable in the case of a truncated data set.
Existence Results for Differential Inclusions with Nonlinear Growth Conditions in Banach Spaces
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Messaoud Bounkhel
2013-01-01
Full Text Available In the Banach space setting, the existence of viable solutions for differential inclusions with nonlinear growth; that is, ẋ(t∈F(t,x(t a.e. on I, x(t∈S, ∀t∈I, x(0=x0∈S, (*, where S is a closed subset in a Banach space , I=[0,T], (T>0, F:I×S→, is an upper semicontinuous set-valued mapping with convex values satisfying F(t,x⊂c(tx+xp, ∀(t,x∈I×S, where p∈ℝ, with p≠1, and c∈C([0,T],ℝ+. The existence of solutions for nonconvex sweeping processes with perturbations with nonlinear growth is also proved in separable Hilbert spaces.
Directory of Open Access Journals (Sweden)
Sebastião Martins Filho
2008-09-01
Full Text Available Neste trabalho foi utilizada a metodologia Bayesiana para ajustar o modelo não-linear logístico para dados de crescimento de duas cultivares de feijoeiro, "Neguinho" e "Carioca". O delineamento experimental utilizado foi o inteiramente casualizado, com vinte repetições, no esquema de parcelas subdivididas, sendo que os tratamentos principais foram constituídos pelas cultivares e as subparcelas foram constituídas por 17 períodos de avaliações, do plantio até aos 85 dias. A metodologia permitiu comparar as curvas de crescimentos sem utilizar a teoria assintótica e estes resultados mostraram um maior incremento em altura para a cultivar "Carioca".In this paper the Bayesian methodology was used to fit the logistic nonlinear model to growth data of two common bean cultivars, 'Neguinho' and 'Carioca'. The experiment was a split plot under a completely randomized design with twenty replicates, being the main treatments constituted by cultivars and the sub plots constituted by seventeen periods of evaluations, from planting to 85 days. The methodology allowed comparing the growth curves without using the asymptotic theory, and these results showed a larger height increment for the 'Carioca' cultivar.
Growth curves of three human malignant tumors transplanted to nude mice
DEFF Research Database (Denmark)
Spang-Thomsen, M; Nielsen, A; Visfeldt, J
1980-01-01
Experimental growth data for three human malignant tumors transplanted to nude mice of BALB/c origin are analyzed statistically in order to investigate whether they can be described according to the Gompertz function. The aim is to set up unequivocal standards for planned therapeutic experiments...... and to develop an essential part of the determination of proliferation parameters for the tumors. The results indicate that the course of tumor growth can be described with good approximation by the Gompertz function. A transformation of this function depicts the growth rectilinearly and appears to be suitable...... mice. For tumors whose growth is described according to the Gompertz function, recording of the growth of the tumor size in two dimensions is sufficient for calculating other relevant growth parameters, if the three linear tumor measurements are proportional throughout the growth period. The initial...
Nonlinear mechanics of surface growth for cylindrical and spherical elastic bodies
Sozio, Fabio; Yavari, Arash
2017-01-01
In this paper we formulate the initial-boundary value problems of accreting cylindrical and spherical nonlinear elastic solids in a geometric framework. It is assumed that the body grows as a result of addition of new (stress-free or pre-stressed) material on part of its boundary. We construct Riemannian material manifolds for a growing body with metrics explicitly depending on the history of applied external loads and deformation during accretion and the growth velocity. We numerically solve the governing equilibrium equations in the case of neo-Hookean solids and compare the accretion and residual stresses with those calculated using the linear mechanics of surface growth.
Simulation of 3D tumor cell growth using nonlinear finite element method.
Dong, Shoubing; Yan, Yannan; Tang, Liqun; Meng, Junping; Jiang, Yi
2016-01-01
We propose a novel parallel computing framework for a nonlinear finite element method (FEM)-based cell model and apply it to simulate avascular tumor growth. We derive computation formulas to simplify the simulation and design the basic algorithms. With the increment of the proliferation generations of tumor cells, the FEM elements may become larger and more distorted. Then, we describe a remesh and refinement processing of the distorted or over large finite elements and the parallel implementation based on Message Passing Interface to improve the accuracy and efficiency of the simulation. We demonstrate the feasibility and effectiveness of the FEM model and the parallelization methods in simulations of early tumor growth.
Growth and characterization of L-valine - a nonlinear optical crystal
Energy Technology Data Exchange (ETDEWEB)
Moitra, S.; Kar, T. [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700032 (India)
2010-01-15
The growth of a new nonlinear optical material L-valine by solvent evaporation method is reported here. To grow good quality crystals pH value of growth solution has been optimized and solubility of L-valine in different solvents and different pH values was determined. The grown crystals were characterized by IR, single crystal XRD, DTA and TGA, optical transmission and second harmonic generation (SHG) efficiency measurement. SHG efficiency of L-valine was found equivalent to KDP and its transmission is 75%-80% from ultraviolet to near IR region. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Energy Technology Data Exchange (ETDEWEB)
Orubu, Christopher O. [Department of Economics, Delta State University, Abraka (Nigeria); Omotor, Douglason G., E-mail: yomotor@yahoo.com [Department of Economics, Delta State University, Abraka (Nigeria)
2011-07-15
This study investigated the relationship between per capita income and environmental degradation in Africa, using longitudinal data on suspended particulate matter and organic water pollutants. The specific objective was to estimate environmental Kuznets curves for two indicators of environmental quality and to establish whether the estimated relationships conform to the inverted U-shape hypothesis. The results of the empirical investigation generally suggest the existence of an environmental Kuznets curve for suspended particulate matter. In the case of organic water pollutants, the evidence weighs more in favor of rising pollution as per capita income increases. The turning point levels of income established for the two indicators of environmental quality were however generally low, when compared to evidence from existing studies. On the face value, this suggests that African countries may be turning the corner of the environmental Kuznets curve, much faster, and at lower levels of income, much in line with the emerging idea of a 'revised environmental Kuznets curve'. The results also suggest that economic growth and rising incomes may matter in African countries in order to curb pollution from these pollutants, but more stringent policy measures, particularly at the industrial level would be required to curb environmental degradation from organic water pollutants. - Highlights: > The specific objective was to establish whether the relationships conform to the inverted U-shape hypothesis. > Evidence suggests the existence of an environmental Kuznets curve for suspended particulate matter. > The turning point levels of income established for the two indicators were however generally low. > We conclude that African countries may be turning the corner of the environmental Kuznets curve, much faster, and at lower levels of income.
Muhammad, Anees; Ishfaq, Ahmed
2011-01-01
The debate of environmental issues and their analysis is of vital interest for economic policies. Institutions are engaged in identifying and estimating the extent of environmental impact of determinants controllable via policy measures. Annual data from the on Carbon Dioxide emission, economic growth, consumption of energy, openness for foreign trade, urbanization, industrial growth and agriculture growth on Pakistan is used for 1971 to 2007. Augmented Vector Autoregression technique and coi...
Rajnicek, A M; McCaig, C. D.; Gow, N.A.
1994-01-01
Directional growth in response to electric fields (galvanotropism) is known for eukaryotic cells as diverse as fibroblasts, neurons, algae, and fungal hyphae. The mechanism is not understood, but all proposals invoke actin either directly or indirectly. We applied electric fields to bacteria (which are inherently free of actin) to determine whether actin was essential for galvanotropism. Field-treated (but not control) Enterobacter cloacae and Escherichia coli cells curved rapidly toward the ...
Directory of Open Access Journals (Sweden)
Luís Orlindo Tedeschi
2000-04-01
Full Text Available RESUMO - O objetivo deste trabalho foi analisar sete funções não-lineares para descrever o crescimento de machos e fêmeas da raça Guzerá e seus cruzamentos (3/4Guzerá-1/4Pardo Suíço, 1/2Nelore-1/4Pardo Suíço-1/4Guzerá, 1/2Pardo Suíço-1/2Guzerá, 1/2Chianina-1/4Pardo Suíço-1/4Guzerá, 1/2Caracú-1/2Guzerá, 1/2Caracu-1/4Pardo Suíço-1/4Guzerá submetidos a três níveis de suplementação (sem, durante o período seco e o ano todo, a fim de analisar e selecionar uma função que apresentasse menores desvios de regressão, menor variação residual, maior coeficiente de determinação, menor variação entre os parâmetros dos animais, maior convergência e valor assintótico compatível com o peso adulto observado. A função que melhor se enquadrou nesses parâmetros de seleção foi a função de Gompertz, seguida da função de Von Bertalanffy. A função de Richards apresentou grande dificuldade computacional para o ajuste, resultando em baixa convergência. As funções de Brody apresentaram as maiores estimativas de peso adulto e a função de Gompertz modificada e Logística, as menores.ABSTRACT - The objective of this work was to evaluate seven non linear functions to describe Guzera male and female growth curves, and their crossbreds (3/4Guzera-1/4Brown Swiss, 1/2Nellore-1/4Brown Swiss-1/4Guzera, 1/2Guzera-1/2Brown Swiss, 1/2Chianina- 1/4Brown Swiss-1/4Guzera, 1/2Caracu-1/2Guzera, 1/2Caracu-1/4Brown Swiss-1/4Guzera submitted to three levels of supplementation (without, during the dry period and the whole year, to analize and to select one function which presented lower regression deviation, lower residual sum of squares, higher coefficient of determination, lower variation among animal parameters, higher convergence and assintotic compatible value with the observed mature weight. The function that best express these parameters of selection was the Gompertz, followed by the Von Bertalanffy function. The Richards function
Changing curves: monitoring growth of children and adolescents in The Netherlands
Schonbeck, Y.
2015-01-01
Background: Monitoring human growth is important. It is used to detection of abnormal growth trajectories of children, which may reflect nutritional problems or underlying illness. In a larger population, it can provide information about the health status of this population, for example the
Changing curves: monitoring growth of children and adolescents in The Netherlands
Schonbeck, Y.
2015-01-01
Background: Monitoring human growth is important. It is used to detection of abnormal growth trajectories of children, which may reflect nutritional problems or underlying illness. In a larger population, it can provide information about the health status of this population, for example the prevalen
Changing curves. Monitoring growth of children and adolescents in The Netherlands
Schonbeck, Y.
2015-01-01
Background: Monitoring human growth is important. It is used to detection of abnormal growth trajectories of children, which may reflect nutritional problems or underlying illness. In a larger population, it can provide information about the health status of this population, for example the prevalen
Growth curves of three human malignant tumors transplanted to nude mice
DEFF Research Database (Denmark)
Spang-Thomsen, M; Nielsen, A; Visfeldt, J
1980-01-01
as a standard, e.g. in therapeutic experiments. The course of tumor growth is independent of the size of the transplant, and whether tumors are transplanted in the right or left or both flanks of the recipient mice. Furthermore, the growth does not vary in a systematic way with the number of passages in nude...
Directory of Open Access Journals (Sweden)
Ch. K. Volos
2015-09-01
Full Text Available In today’s globalized economy one of the most crucial factors for the economic growth of a country, especially of a developing country, is the foreign direct investment, not only because of the transfer of capital but also of technology. In this work, the effect of foreign direct investments in a county’s economic growth by using tools of nonlinear dynamics is studied. As a model of the economic growth of a country, a well-known nonlinear discrete-time dynamical system, the Logistic map, is used. The system under study consists of two countries with a strong economic relationship. The source country of foreign direct investments is an industrialized, economically powerful and technologically advanced country that makes significant investments in the host country, which is a developing country and strong dependent from the source country. Simulation results of system’s behavior and especially the bifurcation diagrams reveal the strong connection between the countries of the proposed system and the effect of foreign direct investments in the economic growth of the host country.
Individual differences in the onset of tense marking: a growth-curve analysis.
Hadley, Pamela A; Holt, Janet K
2006-10-01
The purpose of this study was to explore individual differences in children's tense onset growth trajectories and to determine whether any within- or between-child predictors could account for these differences. Twenty-two children with expressive vocabulary abilities in the low-average to below-average range participated. Sixteen children were at risk for specific language impairment (SLI), and 6 children had low-average language abilities. Spontaneous language samples, obtained at 3-month intervals between 2;0 and 3;0, were analyzed to examine change in a cumulative productivity score for 5 tense morphemes: third person singular present, past tense, copula BE, auxiliary BE, and auxiliary DO. Hierarchical linear modeling was used to model intercept and linear growth at 30 months and quadratic growth overall. A growth model that included mean length of utterance (MLU) and MLU growth better explained within-child productivity score growth trajectories than a parallel model with vocabulary and vocabulary growth. Significant linear growth in productivity scores remained even after a control for MLU was in place. When between-child predictors were added in the final conditional model, only positive family history approached statistical significance, improving the overall estimation of the model's growth parameters. The findings support theoretical models of language acquisition that claim relative independence of tense marking from other more general aspects of vocabulary development and sentence length. The trends for family history are also consistent with proposals implicating faulty genetic mechanisms underlying developmental language disorders. Systematic use of familial risk data is recommended in future investigations examining the relationship between late-talking children and children at risk for SLI.
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Hung-Chi Hsiao
2012-04-01
Full Text Available With the increasing cost of setting up a semiconductor fabrication facility, coupled with significant costs of developing a leading nanotechnology process, aggressive outsourcing (asset-light business models via working more closely with foundry companies is how semiconductor manufacturing firms are looking to strengthen their sustainable competitive advantages. This study aims to construct a market intelligence framework for developing a wafer demand forecasting model based on long-term trend detection to facilitate decision makers in capacity planning. The proposed framework modifies market variables by employing inventory factors and uses a top-down forecasting approach with nonlinear least square method to estimate the forecast parameters. The nonlinear mathematical approaches could not only be used to examine forecasting performance, but also to anticipate future growth of the semiconductor industry. The results demonstrated the practical viability of this long-term demand forecast framework.
Energy Technology Data Exchange (ETDEWEB)
Cheng-Lang, Yang; Chang, Chih-Heng [Department of Managerial Economics, Nanhua University, Chiayi 62102 (China); Lin, Hung-Pin [Department of International Business and Trade, Shu-Te University, Kaohsiung 82445 (China)
2010-11-15
This study investigates the linear and nonlinear causality between the total electricity consumption (TEC) and real gross domestic production (RGDP). Unlike previous literature, we solve the undetermined relation between RGDP and electricity consumption by classifying TEC into industrial sector consumption (ISC) and residential sector consumption (RSC) as well as investigating how TEC, ISC, and RSC influence Taiwan's RGDP. By using the Granger's linear causality test, it is shown that (1) there is a bidirectional causality among TEC, ISC, and RGDP, but a neutrality between RSC and RGDP with regard to the linear causality and (2) there is still a bidirectional causality between TEC and RGDP, but a unidirectional causality between RSC and RGDP with regard to the nonlinear causality. On the basis of (1) and (2), we suggest that the electricity policy formulators loosen the restriction on ISC and limit RSC in order to achieve the goal of economic growth. (author)
Energy Technology Data Exchange (ETDEWEB)
Yang, Cheng-Lang [Department of Managerial Economics, Nanhua University, Chiayi 62102, Taiwan (China); Lin, Hung-Pin, E-mail: lhp0606@stu.edu.t [Department of International Business and Trade, Shu-Te University, Kaohsiung 82445, Taiwan (China); Chang, Chih-Heng [Department of Managerial Economics, Nanhua University, Chiayi 62102, Taiwan (China)
2010-11-15
This study investigates the linear and nonlinear causality between the total electricity consumption (TEC) and real gross domestic production (RGDP). Unlike previous literature, we solve the undetermined relation between RGDP and electricity consumption by classifying TEC into industrial sector consumption (ISC) and residential sector consumption (RSC) as well as investigating how TEC, ISC, and RSC influence Taiwan's RGDP. By using the Granger's linear causality test, it is shown that (i) there is a bidirectional causality among TEC, ISC, and RGDP, but a neutrality between RSC and RGDP with regard to the linear causality and (ii) there is still a bidirectional causality between TEC and RGDP, but a unidirectional causality between RSC and RGDP with regard to the nonlinear causality. On the basis of (i) and (ii), we suggest that the electricity policy formulators loosen the restriction on ISC and limit RSC in order to achieve the goal of economic growth.
An extensive weight-driven network with non-linear growth information
Wang, Lin; Qing Zhang, Gui; Lun Chen, Tian
2008-12-01
In many real-world networks such as the Internet, World Wide Web, etc., the number of edges grows in time in a nonlinear fashion. We consider growing weighted networks in which the number of outgoing edges is a nonlinear function of time and the evolution of the edges' weight is based on a mixed mechanism of weight-driven and inner selection dynamics. Moreover, two kinds of selection fashion of nodes (connected by newly established edges) have been investigated. In the common accelerating growth model, the network exhibits a wide-range power law distribution of node strengths. In the poverty alleviation model, node strength distribution can display transition from power law distribution to Poission-like distribution. The clustering coefficient, the weighted shortest path and the correlation property have been investigated simultaneously.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Objective To explore the biological properties of keratinocytes from differently-aged healthy human beings. Methods Keratinocytes from fetus,teenager and middle-aged groups were separated and cultured. The population doubling time (PDT) and cell growth curve in different cells were compared,and the cell cycles were analyzed by flow cytometry. Results ① In primary culture of keratinocytes,the adherence time in middle-aged group was longer than that in fetus and teenager groups. However,all cell morphology sh...
McClure, M K; Calvet, N; Espaillat, C; Hartmann, L; Sargent, B; Watson, D M; Ingleby, L; Hernandez, J
2013-01-01
The dust sublimation walls of disks around T Tauri stars represent a directly observable cross-section through the disk atmosphere and midplane. Their emission properties can probe the grain size distribution and composition of the innermost regions of the disk, where terrestrial planets form. Here we calculate the inner dust sublimation wall properties for four classical T Tauri stars with a narrow range of spectral types and inclination angles and a wide range of mass accretion rates to determine the extent to which the walls are radially curved. Best-fits to the near- and mid-IR excesses are found for curved, 2-layer walls in which the lower layer contains larger, hotter, amorphous pyroxene grains with Mg/(Mg+Fe)=0.6 and the upper layer contains submicron, cooler, mixed amorphous olivine and forsterite grains. As the mass accretion rates decrease from 10^(-8) to 10^(-10) Msol/yr, the maximum grain size in the lower layer decreases from 3 to 0.5 microns. We attribute this to a decrease in fragmentation and ...
Describing Growth Pattern of Bali Cows Using Non-linear Regression Models
Directory of Open Access Journals (Sweden)
Mohd. Hafiz A.W
2016-12-01
Full Text Available The objective of this study was to evaluate the best fit non-linear regression model to describe the growth pattern of Bali cows. Estimates of asymptotic mature weight, rate of maturing and constant of integration were derived from Brody, von Bertalanffy, Gompertz and Logistic models which were fitted to cross-sectional data of body weight taken from 74 Bali cows raised in MARDI Research Station Muadzam Shah Pahang. Coefficient of determination (R2 and residual mean squares (MSE were used to determine the best fit model in describing the growth pattern of Bali cows. Von Bertalanffy model was the best model among the four growth functions evaluated to determine the mature weight of Bali cattle as shown by the highest R2 and lowest MSE values (0.973 and 601.9, respectively, followed by Gompertz (0.972 and 621.2, respectively, Logistic (0.971 and 648.4, respectively and Brody (0.932 and 660.5, respectively models. The correlation between rate of maturing and mature weight was found to be negative in the range of -0.170 to -0.929 for all models, indicating that animals of heavier mature weight had lower rate of maturing. The use of non-linear model could summarize the weight-age relationship into several biologically interpreted parameters compared to the entire lifespan weight-age data points that are difficult and time consuming to interpret.
Torres, D Diego
2015-03-01
Regarding the methods used to examine the early maternal age-child academic outcomes relationship, the extant literature has tended to examine change using statistical analyses that fail to appreciate that individuals vary in their rates of growth. Of the one study I have been able to find that employs a true growth model to estimate this relationship, the authors only controlled for characteristics of the maternal household after family formation; confounding background factors of mothers that might select them into early childbearing, a possible source of bias, were ignored. The authors' findings nonetheless suggested an inverse relationship between early maternal age, i.e., a first birth between the ages of 13 and 17, and Canadian adolescents' mean math performance at age 10. Early maternal age was not related to the linear slope of age. To elucidate whether the early maternal age-child academic outcomes association, treated in a growth context, is consistent with this finding, the present study built on it using US data and explored children's mathematics and reading trajectories from age 5 on. Its unique contribution is that it further explicitly controlled for maternal background factors and employed a three-level growth model with repeated measures of children nested within their mothers. Though the strength of the relationship varied between mean initial academic performance and mean academic growth, results confirmed that early maternal age was negatively related to children's mathematics and reading achievement, net of post-teen first birth child-specific and maternal household factors. Once maternal background factors were included, there was no statistically significant relationship between early maternal age and either children's mean initial mathematics and reading scores or their mean mathematics and reading growth. Copyright © 2014 Elsevier Inc. All rights reserved.
Hyankova, Ludmila; Novotna, Bozena; Darras, Veerle
2009-01-01
Abstract 1. Changes in the relative weights of carcass, abdominal fat, breast and leg muscles, and plasma thyroid hormone concentrations occurring during the first six weeks of postnatal growth were analysed in males of HG and LG lines divergently selected for high and low relative body weight (BW) gain between 11 and 28 d of age, respectively, and constant adult BW. 2. The 2nd week of postnatal life was a critical age at which the HG males exhibited a relatively faster growth i...
Institute of Scientific and Technical Information of China (English)
叶伟庆; 杜炳旺; 刘宜林; 陈运冬; 陈建; 李东华
2014-01-01
Xinyi HuaiXiang Chicken is a famous chicken breed that listed in the National Animal Genetic Resources Protection List,the study of early growth rules of Xinyi HuaiXiang chicken provide a evidence for its genetic resources conservation and trains breeding.The growth curve of A,B strains of HuaiXiang hen from 0 to 9 weeks old was analyzed and fitted with three kinds of nonlinear models (Gompertz, Logistic, von Bertalanffy).The growth curves were appropriately fitted with three models. The Bertalanffy model had the best effect on fitting with the growth curves of A strain hen (R2=0.996), its growth inflexion was 10.165 weeks and 1047.7g.;The Gompertz model had the best effect on fitting with the growth curves of B strain hen(R2=0.997), its growth inflexion was 8.008 weeks and 748.3g.It is feasible to analyze and fit the growth curve of the HuaiXiang chicken using the three models.%信宜怀乡鸡作为列入国家畜禽遗传资源保护名录的著名品种，为了解其肉种鸡的早期生长发育规律，为其遗传资源保护和品系选育提供参考依据。使用Logistic、Gompertz和Bertallanffy 3种非线性生长模型对怀乡鸡A、B两个品系母鸡0~9周龄早期体重生长数据进行曲线拟合和分析。3种模型均能很好地模拟怀乡鸡生长曲线，Bertalanffy模型的拟合A品系母鸡生长效果最佳（R2=0.996），其拐点为（10.165，1047.7）；Gompertz模型的拟合B品系母鸡生长效果最佳（R2=0.997），其拐点为（8.008，748.3）。3种模型对信宜怀乡鸡生长曲线的拟合和分析是可行的，可及时掌握怀乡鸡的生长发育规律。
Random regression models in the evaluation of the growth curve of Simbrasil beef cattle
Mota, M.; Marques, F.A.; Lopes, P.S.; Hidalgo, A.M.
2013-01-01
Random regression models were used to estimate the types and orders of random effects of (co)variance functions in the description of the growth trajectory of the Simbrasil cattle breed. Records for 7049 animals totaling 18,677 individual weighings were submitted to 15 models from the third to the
Directory of Open Access Journals (Sweden)
Mahalingam Vasantha
Full Text Available Tuberculosis still remains a major public health problem even though it is treatable and curable. Weight gain measurement during anti tuberculosis (TB treatment period is an important component to assess the progress of TB patients. In this study, Latent Growth Models (LGMs were implemented in a longitudinal design to predict the change in weight of TB patients who were given three different regimens under randomized controlled clinical trial for anti-TB treatment. Linear and Quadratic LGMs were fitted using Mplus software. The age, sex and treatment response of the TB patients were used as time invariant independent variables of the growth trajectories. The quadratic trend was found to be better in explaining the changes in weight without grouping than the quadratic model for three group comparisons. A significant increase in the change of weight over time was identified while a significant quadratic effect indicated that weights were sustained over time. The growth rate was similar in both the groups. The treatment response had significant association with the growth rate of weight scores of the patients.
Random regression models in the evaluation of the growth curve of Simbrasil beef cattle
Mota, M.; Marques, F.A.; Lopes, P.S.; Hidalgo, A.M.
2013-01-01
Random regression models were used to estimate the types and orders of random effects of (co)variance functions in the description of the growth trajectory of the Simbrasil cattle breed. Records for 7049 animals totaling 18,677 individual weighings were submitted to 15 models from the third to the f
Necessary and sufficient conditions for the existence of the UMRE estimator in growth curve models
Institute of Scientific and Technical Information of China (English)
吴启光
1995-01-01
The necessary and sufficient conditions are derived for the existence of the uniformly minimum risk equivariant (UMRE) estimator of regression coefficient matrix in normal growth carve models with arbitrary covariance matrix or uniform oovananoe structure or serial covariance structure under an affine group and a transitive group of transformations for quadratic losses and matrix losses, respectively.
Structural Change, Economic Growth and the Environmental Kuznets Curve: A Theoretical Perspective
H.L.F. de Groot (Henri)
2003-01-01
textabstractThe question of whether economic growth will ultimately resolve environmental problems has recently been discussed in a mainly empirical literature. One of the mechanisms that can explain the finding of an inverted U-shaped relationship between income and emissions relies on the changes
Institute of Scientific and Technical Information of China (English)
Hui-qun Ma; Jie Feng; Lech Chyczewski; Jacek Niklinski
2009-01-01
Objective To explore the biological properties of keratinocytes from differently-aged healthy human beings. Methods Keratinocytes from fetus, teenager and middle-aged groups were separated and cultured. The population doubling time (PDT) and cell growth curve in different cells were compared, and the cell cycles were analyzed by flow cytometry. Results ① In primary culture of keratinocytes, the adherence time in middle-aged group was longer than that in fetus and teenager groups. However, all cell morphology showed no obvioas differences. In subculture of kecatinocytes, with donator's age increasing, time of cell adherence prolonged, passage number decreused and differences in cell morphology were obrioas. ② The average PDT of keratinocytes was shorter in fetus group than in teenager and middle-aged groups. Bat difference in cell growth curve between different passages was not observed. ③ Keratinocytes showed G2/M period in fetus group but G0/G1 period in teenager and middle-aged groups mainly. Conclusion As age increases, the biological properties of keratinocytes change obviously.
Smith, Robert E; Seljak, Uros
2009-01-01
We investigate the impact of nonlinear evolution of the gravitational potentials in the LCDM model on the Integrated Sachs-Wolfe (ISW) contribution to the CMB temperature power spectrum, and on the cross-power spectrum of the CMB and a set of biased tracers of the mass. We use an ensemble of N-body simulations to directly follow the potentials and compare results to perturbation theory (PT). The predictions from PT match the results to high precision for k100 the departures are more significant, however the CMB signal is more than a factor 10^3 larger at this scale. Nonlinear ISW effects therefore play no role in shaping the CMB power spectrum for l<1500. We analyze the CMB--density tracer cross-spectrum using simulations and renormalized bias PT, and find good agreement. The usual assumption is that nonlinear evolution enhances the growth of structure and counteracts linear ISW on small scales, leading to a change in sign of the CMB-LSS cross-spectrum at small scales. However, PT analysis suggests that th...
Ahmed, Abubaker Ali
As part of the structural integrity research of the National Aging Aircraft Research Program, a comprehensive study on multiple-site damage (MSD) initiation and growth in a pristine lap-joint fuselage panel has been conducted. The curved stiffened fuselage panel was tested at the Full-Scale Aircraft Structural Test Evaluation and Research (FASTER) facility located at the Federal Aviation Administration William J. Hughes Technical Center. A strain survey test was conducted to verify proper load application. The panel was then subjected to a fatigue test with constant-amplitude cyclic loading. The applied loading spectrum included underload marker cycles so that crack growth history could be reconstructed from post-test fractographic examinations. Crack formation and growth were monitored via nondestructive and high-magnification visual inspections. Strain gage measurements recorded during the strain survey tests indicated that the inner surface of the skin along the upper rivet row of the lap joint experienced high tensile stresses due to local bending. During the fatigue loading, cracks were detected by eddy-current inspections at multiple rivet holes along the upper rivet row. Through-thickness cracks were detected visually after about 80% of the fatigue life. Once MSD cracks from two adjacent rivet holes linked up, there was a quick deterioration in the structural integrity of the lap joint. The linkup resulted in a 2.87" (72.9-mm) lead fatigue crack that rapidly propagated across 12 rivet holes and crossed over into the next skin bay, at which stage the fatigue test was terminated. A post-fatigue residual strength test was then conducted by loading the panel quasi-statically up to final failure. The panel failed catastrophically when the crack extended instantaneously across three additional bays. Post-test fractographic examinations of the fracture surfaces in the lap joint of the fuselage panel were conducted to characterize subsurface crack initiation and
Minimal seeds for shear flow turbulence: using nonlinear transient growth to touch the edge of chaos
Pringle, Chris C T; Kerswell, Rich R
2011-01-01
We propose a general strategy for determining the minimal finite amplitude isturbance to trigger transition to turbulence in shear flows. This involves constructing a variational problem that searches over all disturbances of fixed initial amplitude, which respect the boundary conditions, incompressibility and the Navier--Stokes equations, to maximise a chosen functional over an asymptotically long time period. The functional must be selected such that it identifies turbulent velocity fields by taking significantly enhanced values compared to those for laminar fields. We illustrate this approach using the ratio of the final to initial perturbation kinetic energies (energy growth) as the functional and the energy norm to measure amplitudes in the context of pipe flow. Our results indicate that the variational problem yields a smooth converged solution providing the amplitude is below the threshold amplitude for transition. This optimal is the nonlinear analogue of the well-studied (linear) transient growth opt...
Asymptotic behavior of nonlinear semigroup describing a model of selective cell growth regulation.
Arino, O; Kimmel, M
1991-01-01
A new scheme of regulation of cell population growth is considered, called the selective growth regulation. The principle is that cells are withdrawn from proliferation depending on their contents of certain biochemical species. The dynamics of the cell population structured by the contents of this species is described by the functional integral equation model, previously introduced by the authors. The solutions of the model equations generate a semigroup of nonlinear positive operators. The main problem solved in this paper concerns stability of the equilibria of the model. This requires stating and proving of an original abstract result on the spectral radius of a perturbation of a semigroup of positive linear operators. Biological applications are discussed.
Energy Technology Data Exchange (ETDEWEB)
Imre, K.
1993-05-01
We are developing a profile analysis code for the statistical estimation of the parametric dependencies of the temperature and density profiles in tokamaks. Our code uses advanced statistical techniques to determine the optimal fit, i.e. the fit which minimized the predictive error. For a forty TFTR Ohmic profile dataset, our preliminary results indicate that the profile shape depends almost exclusively on q{sub a}{prime} but that the shape dependencies are not Gaussian. We are now comparing various shape models on the TFTR data. In the first six months, we have completed the core modules of the code, including a B-spline package for variable knot locations, a data-based method to determine the optimal smoothing parameters, self-consistent estimation of the bias errors, and adaptive fitting near the plasma edge. Visualization graphics already include three dimensional surface plots, and discharge by discharge plots of the predicted curves with error bars together with the actual measurements values, and plots of the basis functions with errors.
Growth curves for school children from Kuching, Sarawak: a methodological development.
Bong, Yii Bonn; Shariff, Asma Ahmad; Mohamed, Abdul Majid; Merican, Amir Feisal
2015-03-01
In this article, the authors propose reference curves for height and weight for school children in the Kuching area, Sarawak. The school children were from primary to secondary schools (aged 6.5 to 17 years old) and comprised both genders. Anthropometric measurements and demographic information for 3081 school-aged children were collected (1440 boys and 1641 girls). Fitted line plots and percentiles for height and weight (3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles) were obtained. The height of school boys and school girls were almost similar at the start of their school-going age. For school girls, height and weight values stabilized when they reached 16 or 17 years old but kept increasing for school boys. School boys were taller than school girls as they entered adolescence. Height differences between school boys and school girls became significantly wider as they grew older. Chinese school children were taller and heavier than those of other ethnic groups. © 2012 APJPH.
Energy Technology Data Exchange (ETDEWEB)
Watson, C. R.; Cochran, M. I.; Thomas, J. M.; Eberhardt, L. L
1977-11-01
To find a mathematical model which describes (fits) data from a process which is fundamentally nonlinear, one usually uses nonlinear least-squares techniques on maxicomputers. These usually run in batch mode with the user supplying a model and initial ''guesstimates'' of its parameters. However, fitting the model to the data can be considered an art because computer algorithms either converge to true solutions, or converge to erroneous solutions, or fail to converge, depending on the quality of the guesstimates. It is slow and expensive to try enough runs to obtain a logical solution (unless one makes lucky initial guesses). An interactive BASIC procedure was developed which runs on either the PDP-11/34 under RT-11 or the PDP-11/70 under IAS. These programs help the investigator quickly fit the model to the data and statistically evaluate the differences between the two. The parameter estimates thus determined may then be used as guesstimates for the more precise maxicomputer codes. The key to the system is the re-enterant nature of the curve fitting routine (allowed only with a language such as INTERPRETED BASIC). The user supplies estimates of the parameters for the selected model (18 are currently available, and users can easily write their own). The computer tries a few iterative refinements (by using Taylor series expansion of partial derivatives to obtain linearization) of the estimates in an attempt to minimize the deviations between the values predicted by the model and the observed data. The user can observe as the program executes whether the result is a logical solution. If not, he may stop the process, enter new guesstimates, and examine those results, try again, or select a new model.
Linear and nonlinear causality between renewable energy consumption and economic growth in the USA
Directory of Open Access Journals (Sweden)
Haiyun Xu
2016-12-01
Full Text Available This study aims to investigate Granger causality between renewable energy consumption (REC and economic growth (EG for USA. To accomplish this objective and to add the stronger evidence to the controversial issue, the tests were done under a new framework that embeds wavelet analysis, a novel tool, in nonlinear causality test approaches developed recently. The classical linear causality test procedure was also involved for comparison. The empirical data sources from the USA Energy Information Administration and Economist Intelligence Unit (EIU CountryData database. Sample period is from January 1993 to October 2014. The results indicate significantly the existence of unidirectional causality from EG to REC and support the conservation hypothesis. In additional, further evidences show that the causal relationship among them is not constant and depends on the time scale or frequency ranges, and that wavelet analysis is an important aid to capture the nonlinear causality. This suggests that renewable energy limitations do not seem to damage economic growth. These results have implications of importance for research analysts as well as policy makers of energy economy.
Directory of Open Access Journals (Sweden)
Mäntysaari Esa A
2006-06-01
Full Text Available Abstract A method based on Taylor series expansion for estimation of location parameters and variance components of non-linear mixed effects models was considered. An attractive property of the method is the opportunity for an easily implemented algorithm. Estimation of non-linear mixed effects models can be done by common methods for linear mixed effects models, and thus existing programs can be used after small modifications. The applicability of this algorithm in animal breeding was studied with simulation using a Gompertz function growth model in pigs. Two growth data sets were analyzed: a full set containing observations from the entire growing period, and a truncated time trajectory set containing animals slaughtered prematurely, which is common in pig breeding. The results from the 50 simulation replicates with full data set indicate that the linearization approach was capable of estimating the original parameters satisfactorily. However, estimation of the parameters related to adult weight becomes unstable in the case of a truncated data set.
Braverman, Marc T; Aarø, Leif Edvard; Bontempo, Daniel E; Hetland, Jørn
2010-06-01
Norway passed legislation banning smoking in restaurants, bars and other public spaces in 2004. This study tracks changes in hospitality workers' attitudes towards Norway's ban over three time points, using growth modelling analysis to examine predictors of attitude change. Participants were a national sample of 1525 bar and restaurant workers. Surveys were conducted, by phone or internet, one month before the ban's implementation and at 4 and 12 months thereafter. Exploratory principal components analysis of nine survey items revealed one primary attitude component. A latent growth model was fitted to the data to examine trajectories of attitude change and individual differences in rate of change. Respondents supported the ban before implementation and increased support at 4 months (p=0.021) and again at 12 months (p=0.001). Concern for one's job followed a quadratic trend, increasing at 4 months and decreasing at 12 months (phospitality workers increased their support of the ban over its first year. The strong influence of the within-person variables leads to two primary policy recommendations. First, support should be provided to assist cessation efforts and prevent relapse. Second, informational campaigns should inform hospitality workers about evidence that smoking bans are not economic threats to the industry.
Freetly, H C; Kuehn, L A; Cundiff, L V
2011-08-01
The objective of this study was to evaluate the growth curves of females to determine if mature size and relative rates of maturation among breeds differed. Body weight and hip height data were fitted to the nonlinear function BW = f(age) = A - Be(k×age), where A is an estimate of mature BW and k determines the rate that BW or height moves from B to A. Cows represented progeny from 28 Hereford, 38 Angus, 25 Belgian Blue, 34 Brahman, 8 Boran, and 9 Tuli sires. Bulls from these breeds were mated by AI to Angus, Hereford, and MARC III composite (1/4 Angus, 1/4 Hereford, 1/4 Red Poll, and 1/4 Pinzgauer) cows to produce calves in 1992, 1993, and 1994. These matings resulted in 516 mature cows whose growth curves were subsequently evaluated. Hereford-sired cows tended to have heavier mature BW, as estimated by parameter A, than Angus- (P=0.09) and Brahman-sired cows (P=0.06), and were heavier than the other breeds (P Brahman-sired cows (P=0.94). Brahman-sired cows had a heavier mature BW than Boran- (P Brahman (P Brahman-sired cows took longer to mature than Boran- (P=0.03) or Belgian Blue-sired cows (P=0.003). Belgian Blue-sired cows were faster maturing than Tuli-sired cows (P=0.02). Brahman-sired cows had reached a greater proportion of their mature BW at puberty than had Hereford- (P < 0.001), Tuli- (P=0.003), and Belgian Blue-sired cows (P=0.001). Boran-sired cows tended to have reached a greater proportion of their mature BW at puberty than had Angus-sired cows (P=0.09), and had reached a greater proportion of their mature BW at puberty than had Hereford- (P < 0.001), Tuli- (P < 0.001), and Belgian Blue-sired cows (P < 0.001). Within species of cattle, the relative range in proportion of mature BW at puberty (Bos taurus 0.56 through 0.58, and Bos indicus 0.60) was highly conserved, suggesting that proportion of mature BW is a more robust predictor of age at puberty across breeds than is absolute weight or age. © 2011 American Society of Animal Science. All rights
Sathya, P.; Gopalakrishnan, R.
2015-06-01
Cyclohexylammonium 4-Methoxy Benzoate (C4MB) was synthesised and the functional groups were confirmed by FTIR analysis. The purified C4MB (by repeated recrystallisation) was used for single crystal growth. Single crystal of cyclohexylammonium 4-methoxy benzoate was successfully grown by slow evaporation solution growth method at ambient temperature. Structural orientations were determined from single crystal X-ray diffractometer. Optical absorption and cut off wavelength were identified by UV-Visible spectroscopy. Thermal stability of the crystal was studied from thermogravimetric and differential thermal analyses curves. Mechanical stability of the grown crystal was analysed by Vicker's microhardness tester. The Second Harmonic Generation (SHG) study revealed that the C4MB compound exhibits the SHG efficiency 3.3 times greater than KDP crystal.
Energy Technology Data Exchange (ETDEWEB)
Sathya, P.; Gopalakrishnan, R., E-mail: krgkrishnan@annauniv.edu [Crystal Research Lab, Department of Physics, Anna University, Chennai-600002 (India)
2015-06-24
Cyclohexylammonium 4-Methoxy Benzoate (C4MB) was synthesised and the functional groups were confirmed by FTIR analysis. The purified C4MB (by repeated recrystallisation) was used for single crystal growth. Single crystal of cyclohexylammonium 4-methoxy benzoate was successfully grown by slow evaporation solution growth method at ambient temperature. Structural orientations were determined from single crystal X-ray diffractometer. Optical absorption and cut off wavelength were identified by UV-Visible spectroscopy. Thermal stability of the crystal was studied from thermogravimetric and differential thermal analyses curves. Mechanical stability of the grown crystal was analysed by Vicker’s microhardness tester. The Second Harmonic Generation (SHG) study revealed that the C4MB compound exhibits the SHG efficiency 3.3 times greater than KDP crystal.
Schofield, Matthew R; Barker, Richard J; Taylor, Peter
2013-12-01
We use Bayesian methods to explore fitting the von Bertalanffy length model to tag-recapture data. We consider two popular parameterizations of the von Bertalanffy model. The first models the data relative to age at first capture; the second models in terms of length at first capture. Using data from a rainbow trout Oncorhynchus mykiss study we explore the relationship between the assumptions and resulting inference using posterior predictive checking, cross validation and a simulation study. We find that untestable hierarchical assumptions placed on the nuisance parameters in each model can influence the resulting inference about parameters of interest. Researchers should carefully consider these assumptions when modeling growth from tag-recapture data. © 2013, The International Biometric Society.
Growth in Adolescent Self-Regulation and Impact on Sexual Risk-Taking: A Curve-of-Factors Analysis.
Crandall, AliceAnn; Magnusson, Brianna M; Novilla, M Lelinneth B
2017-06-29
Adolescent self-regulation is increasingly seen as an important predictor of sexual risk-taking behaviors, but little is understood about how changes in self-regulation affect later sexual risk-taking. Family financial stress may affect the development of self-regulation and later engagement in sexual risk-taking. We examined whether family financial stress influences self-regulation in early adolescence (age 13) and growth in self-regulation throughout adolescence (from age 13-17 years). We then assessed the effects of family financial stress, baseline self-regulation, and the development of self-regulation on adolescent sexual risk-taking behaviors at age 18 years. Using a curve-of-factors model, we examined these relationships in a 6-year longitudinal study of 470 adolescents (52% female) and their parents from a large northwestern city in the United States. Results indicated that family financial stress was negatively associated with baseline self-regulation but not with growth in self-regulation throughout adolescence. Both baseline self-regulation and growth in self-regulation were predictive of decreased likelihood of engaging in sexual risk-taking. Family financial stress was not predictive of later sexual risk-taking. Intervening to support the development of self-regulation in adolescence may be especially protective against later sexual risk-taking.
Energy Technology Data Exchange (ETDEWEB)
Linet, J. Mary [Department of Physics, Loyola College, Nungambakkam, Chennai 600 034 (India); Das, S. Jerome, E-mail: sjeromedas2004@yahoo.co [Department of Physics, Loyola College, Nungambakkam, Chennai 600 034 (India)
2010-09-15
L-threonine single crystal was successfully grown from aqueous solution. The morphology of the grown crystal was compared with the predicted morphology using Bravais-Friedel-Donnay-Harker law and was found to be in good agreement with the predicted morphology. Good optical quality bulk single crystal of enhanced size has been grown using unidirectional crystal growth method. High-resolution X-ray analysis study resulted in a rocking curve with a full width half maximum of 20 arc sec exhibiting the good crystalline quality of the grown crystal. The optical transmission study shows 90% of transmission in the entire visible region that exhibits the good optical quality of the grown crystal. The mechanical properties were analyzed by Vicker's microhardness method.
McPhie, Meghan L; Rawana, Jennine S
2015-04-01
This study examined the influence of physical activity on the trajectory of depression from adolescence through emerging adulthood (EA). Using data from the National Longitudinal Study of Adolescent Health (Waves I to IV), latent growth curve modeling was performed to assess how physical activity and gender influenced depression across adolescence and EA. Higher levels of physical activity in mid-adolescence were associated with lower levels of depression during mid-adolescence and slower inclines and declines in depression over time. Boys had lower levels of depression in mid-adolescence and slower inclines and declines in depression over time compared to girls. Findings provide evidence that current theories on understanding depression and mental health prevention programs may be enhanced by the inclusion of physical activity. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.
Estudo da curva de crescimento de ovinos Santa Inês Analysis of the growth curve of Santa Ines sheep
Directory of Open Access Journals (Sweden)
José Lindenberg Rocha Sarmento
2006-04-01
Full Text Available Utilizaram-se 7.271 registros de pesos do nascimento aos 196 dias de idade de 952 crias de ovinos Santa Inês, controlados de 1983 a 2000, com os objetivos de verificar, entre os modelos Brody, Von Bertalanffy, Logístico, Gompertz e Richards, aquele que melhor descreve a curva média de crescimento e avaliar a influência de efeitos de ambiente sobre os parâmetros estimados. Os parâmetros foram estimados usando-se o procedimento NLIN do SAS. Para verificar se uma única curva seria adequada para descrever o crescimento de machos e fêmeas, nascidos de partos simples ou duplo, aplicou-se um teste de igualdade de parâmetros de modelos não-lineares. Os cinco modelos ajustaram bem os dados de crescimento, entretanto, maior variação dos resíduos foi verificada para os modelos Brody e Logístico. Com base nos desvios médios absolutos dos resíduos, constatou-se que o modelo Gompertz apresentou ajuste médio ligeiramente superior aos modelos Von Bertalanffy e Richards. Machos e fêmeas, nascidos de partos simples e duplo, apresentaram padrões de crescimento divergentes. Os efeitos de grupos contemporâneos, tipo de nascimento e sexo foram importantes fontes de variação para os parâmetros A e K. A correlação estimada entre os parâmetros A e K foi negativa. Melhorias no manejo alimentar devem ser incrementadas, principalmente quanto ao armazenamento de forragem, visando diminuir os efeitos indiretos do clima, o que poderá refletir em menor variação na forma da curva de crescimento.Records of 7,271 weights of 952 lambs measured from birth up to 196 days of age between 1983 and 2000, available from the Agricultural Research Corporation of Paraiba database, were used to model the average growth curve of Santa Ines sheep. The influence of environmental effects on the estimated parameters of the Brody, Von Bertalanffy, Logistic, Gompertz and Richards functions was evaluated using the NLIN procedure of SAS. The growth curve was well fitted
Directory of Open Access Journals (Sweden)
Mazur Anna
2015-03-01
Full Text Available This research empirically explores the relation between carbon dioxide emission and economic growth during the period 1992-2010, using panel data on the European Union countries. Both fixed and random effect models are employed to test the Environmental Kuznets Curve (EKC relationship between CO2 emissions and GDP per capita. While no U-shaped EKC was confirmed empirically for all 28 current EU member states, the graphical analysis demonstrates a justified turning point for CO2 emissions as GDP per capita reaches the level of 23,000 USD. Furthermore, there is a firm empirical ground for the EKC hypothesis based on data from 16 older, relatively high-income EU states. Thus, though not empirically confirmed, there is ample data verifying the existence of the EKC in EU economies.
Choi, Eunhee; Tang, Fengyan; Kim, Sung-Geun; Turk, Phillip
2016-10-01
This study examined the longitudinal relationships between functional health in later years and three types of productive activities: volunteering, full-time, and part-time work. Using the data from five waves (2000-2008) of the Health and Retirement Study, we applied multivariate latent growth curve modeling to examine the longitudinal relationships among individuals 50 or over. Functional health was measured by limitations in activities of daily living. Individuals who volunteered, worked either full time or part time exhibited a slower decline in functional health than nonparticipants. Significant associations were also found between initial functional health and longitudinal changes in productive activity participation. This study provides additional support for the benefits of productive activities later in life; engagement in volunteering and employment are indeed associated with better functional health in middle and old age.
Frison, Eline; Eggermont, Steven
2016-10-01
Despite increasing evidence that specific types of Facebook use (i.e., active private, active public, and passive Facebook use) are differently related to adolescents' well-being, little is known how these types function over the course of adolescence and whether gender and Facebook motives may predict the initial level and changes in these types over time. To address these gaps, Flemish adolescents (ages 12-19) were questioned at three different time points, with six months in between (NTime1 = 1866). Latent growth curve models revealed that active private Facebook use increased over the course of adolescence, whereas public Facebook use decreased. Passive Facebook use, however, remained stable. In addition, gender and Facebook motives were related to initial levels of specific types of Facebook use, and predictive of dynamic change in specific types of Facebook use over time. The discussion focuses on the understanding and implications of these findings.
Padilla-Walker, Laura M; Coyne, Sarah M; Fraser, Ashley M; Dyer, W Justin; Yorgason, Jeremy B
2012-10-01
The current study examined how parents' use of restrictive and active monitoring and deference changed over three years, and examined both adolescent and parent characteristics as predictors of initial levels of media monitoring, as well as change in media monitoring. Participants included 276 mother-child dyads (M age of child = 12.08, SD = .63, 50% female) taken from Time 2 of the Flourishing Families Project, 96% of whom had complete data for Time 4 (N = 266). Active monitoring was the most common approach at the first and second time points, while active monitoring and deference were equally common by the final time point. Latent growth curve analysis revealed that restrictive and active monitoring decreased over time, while deference increased. In addition, both adolescent and parent characteristics were predictive of initial levels of all three types of monitoring, and of change in restrictive monitoring. Discussion focuses on developmental implications of these findings.
Energy Technology Data Exchange (ETDEWEB)
Kim, Sei-wan [Department of Economics, Ewha Womans University, Seoul (Korea, Republic of); Lee, Kihoon, E-mail: khl@cnu.ac.k [Department of Economics, Chungnam National University, Daejeon (Korea, Republic of); Nam, Kiseok [Sy Syms School of Business, Yeshiva University, New York, NY 10033 (United States)
2010-10-15
Using STAR models, we investigate the nonlinear dynamic properties and the interdependence of CO{sub 2} emissions and economic growth for Korea. The estimation results indicate that the growth rate of both CO{sub 2} emissions and industrial production exhibit a significant nonlinear asymmetric dynamics. While the linear Granger causality test finds no causality in any direction, the results of the nonlinear Granger causality tests show a two-way causality between CO{sub 2} emissions and economic growth. The strong mutual causation between CO{sub 2} emissions and economic activities indicates that the economic impact from CO{sub 2} mitigation is expected to be higher in Korea. This suggests that the appropriate energy and environmental policy be to mitigate CO{sub 2} emissions while having less impact on the economy.
Energy Technology Data Exchange (ETDEWEB)
Kim, Sei-wan [Department of Economics, Ewha Womans University, Seoul (Korea); Lee, Kihoon [Department of Economics, Chungnam National University, Daejeon (Korea); Nam, Kiseok [Sy Syms School of Business, Yeshiva University, New York, NY 10033 (United States)
2010-10-15
Using STAR models, we investigate the nonlinear dynamic properties and the interdependence of CO{sub 2} emissions and economic growth for Korea. The estimation results indicate that the growth rate of both CO{sub 2} emissions and industrial production exhibit a significant nonlinear asymmetric dynamics. While the linear Granger causality test finds no causality in any direction, the results of the nonlinear Granger causality tests show a two-way causality between CO{sub 2} emissions and economic growth. The strong mutual causation between CO{sub 2} emissions and economic activities indicates that the economic impact from CO{sub 2} mitigation is expected to be higher in Korea. This suggests that the appropriate energy and environmental policy be to mitigate CO{sub 2} emissions while having less impact on the economy. (author)
Crystal growth of an organic non-linear optical material from the vapour phase
Hou, W
1999-01-01
Due to the potential applications of organic non-linear optical materials in the areas of optical processing and communication, the investigation of the crystal growth of new organic NLO materials has been an active field for the last 20 years. For such uses it is necessary to produce single crystals of high quality and perfection, free of strain and defects. When crystals are grown from the solution and the melt, solvent and the decomposition component in the melt can introduce impurities and imperfection to the as-grown crystals. For crystals grown from vapour phase, in the absence of the solvent, this cannot occur and the method promises to yield single crystals of higher quality. Despite this attraction, little attention has been paid to the vapour phase growth of organic NLO crystals. It was with this in mind that the following investigation was carried out. Using Methyl p-hydroxybenzoate (p-MHB), a potential organic NLO material, a comparison investigation was made of its crystal growth from both the va...
Institute of Scientific and Technical Information of China (English)
王丽丽; 张景绘
2001-01-01
利用非平稳信号的时频分析方法研究了一类非线性系统的频率特性和阻尼特性随运动形态的变化规律，得到了能简洁、直观地反映系统基本非线性动力学特性的广义骨架线性系统(简称GSLS)和骨架曲线,在此基础上，利用时频滤波方法根据系统非平稳响应信号对非线性系统进行辨识,该项工作为非线性系统反问题的研究提供了一条新的途径,%The nonlinear behavior varying with the instantaneous response was analyzed through the joint time_frequency analysis method for a class of S.D.O.F nonlinear system. A masking operator on definite regions is defined and two theorems are presented. Based on these, the nonlinear system is modeled with a special time_varying linear one, called the generalized skeleton linear system(GSLS). The frequency skeleton curve and the damping skeleton curve are defined to describe the main feature of the non_linearity as well. Moreover, an identification method is proposed through the skeleton curves and the time_frequency filtering technique.
Evaluating Non-Linear Regression Models in Analysis of Persian Walnut Fruit Growth
Directory of Open Access Journals (Sweden)
I. Karamatlou
2016-02-01
larger cells and tissues. The second phase includes attainment of final nut form, and it is characterized mainly by chemical changes. These include changes in the shell as the cells become lignified and more important changes in kernel composition. Conclusion: Based on thes tatistical testing and goodness of the fit, the best model between six nonlinear growth models, was double-sigmoid and Richard model swhich can be used to accurately predict fruit growth based on fruit weight, fruit lengt hand width, respectively.
Dynamical patterns and regime shifts in the nonlinear model of soil microorganisms growth
Zaitseva, Maria; Vladimirov, Artem; Winter, Anna-Marie; Vasilyeva, Nadezda
2017-04-01
Dynamical model of soil microorganisms growth and turnover is formulated as a system of nonlinear partial differential equations of reaction-diffusion type. We consider spatial distributions of concentrations of several substrates and microorganisms. Biochemical reactions are modelled by chemical kinetic equations. Transport is modelled by simple linear diffusion for all chemical substances, while for microorganisms we use different transport functions, e.g. some of them can actively move along gradient of substrate concentration, while others cannot move. We solve our model in two dimensions, starting from uniform state with small initial perturbations for various parameters and find parameter range, where small initial perturbations grow and evolve. We search for bifurcation points and critical regime shifts in our model and analyze time-space profile and phase portraits of these solutions approaching critical regime shifts in the system, exploring possibility to detect such shifts in advance. This work is supported by NordForsk, project #81513.
Selvaraju, K; Kirubavathi, K
2013-11-01
The single crystals of bis l-proline hydrogen nitrate (BLPHN) belonging to non-centrosymmetric space group were successfully grown by the slow evaporation solution growth technique. The BLPHN crystals of size 10×7×3mm(3) were obtained in 35days. Initially, the solubility tests were carried out for two solvents such as deionized water and mixed of deionized water-acetone. Among the two solvents, the solubility of BLPHN was found to be the highest in deionized water, so crystallization of BLPHN was done from its aqueous solution. As grown, crystals were characterized by single crystal X-ray diffraction studies and optical transmission spectral studies. Infrared spectroscopy, thermo gravimetric analysis and differential thermal analysis measurements were performed to study the molecular vibration and thermal behavior of the grown BLPHN crystals. Nonlinear optical (NLO) behavior of BLPHN crystal was studied by Kurtz and Perry powder method. Copyright © 2013 Elsevier B.V. All rights reserved.
Growth and characterization of glycinium 3-nitrophthalate nonlinear optical single crystal
Bhuvaneswari, R.; Bharathi, M. Divya; Hemanathan, K.; Murugesan, K. Sakthi
2017-05-01
The potential organic nonlinear optical single crystal of glycinium 3-nitrophthalate has been grown by slow evaporation solution growth technique (SEST) using water solution at room temperature. The single crystal x-ray diffraction confirms the monoclinic structure with the centro symmetric space group P21/c. The crystal shows good transparency about (80%) in the entire visible region with a lower cut off wavelength of 377nm. The physico-chemical changes, stability and decomposition stages of the Glycinium 3-Nitrophthalate compound were established by TG-DSC studies. The laser induced surface damage threshold value 6.2 GW/cm2 indicates that this material can be used for high power laser applications.
Thomas Joseph Prakash, J.; Martin Sam Gnanaraj, J.
2015-01-01
Semiorganic nonlinear optical crystals of Cadmium Thiosemicarbazide Bromide was grown by slow evaporation solution growth technique. The unit cell parameters were estimated by subjecting the crystals to single crystal X-ray diffraction. The grown crystals were subjected to Powder X-ray diffraction for analyzing the crystalline nature of the sample. FTIR studies reveal the functional groups and the optical characters were analyzed by UV-Vis spectral studies. Mechanical stability of the sample was assessed by Vicker's micro hardness test. The presence of surface dislocations was identified by chemical etching technique. Antibacterial study was carried out against ACDP declared harmful pathogens. SHG efficiency of CTSB crystal was tested using Nd: YAG laser and it was found to be ∼1.8 times that of potassium dihydrogen phosphate.
Synthesis, crystal growth and studies on non-linear optical property of new chalcones
Sarojini, B. K.; Narayana, B.; Ashalatha, B. V.; Indira, J.; Lobo, K. G.
2006-09-01
The synthesis, crystal growth and non-linear optical (NLO) property of new chalcone derivatives are reported. 4-Propyloxy and 4-butoxy benzaldehydes were made to under go Claisen-Schmidt condensation with 4-methoxy, 4-nitro and 4-phenoxy acetophenones to form corresponding chalcones. The newly synthesized compounds were characterized by analytical and spectral data. The Second harmonic generation (SHG) efficiency of these compounds was measured by powder technique using Nd:YAG laser. Among tested compounds three chalcones showed NLO property. The chalcone 1-(4-methoxyphenyl)-3-(4-propyloxy phenyl)-2-propen-1-one exhibited SHG conversion efficiency 2.7 times that of urea. The bulk crystal of 1-(4-methoxyphenyl)-3-(4-butoxyphenyl)-2-propen-1-one (crystal size 65×28×15 mm 3) was grown by slow-evaporation technique from acetone. Microhardness of the crystal was tested by Vicker's microhardness method.
Energy Technology Data Exchange (ETDEWEB)
Fodor, I K; Holtz-Morris, A E; McCutchen-Maloney, S L
2005-09-08
The Phenotype MicroArray technology of Biolog, Inc. (Hayward, CA) measures the respiration of cells as a function of time in thousands of microwells simultaneously, and thus provides a high-throughput means of studying cellular phenotypes. The microwells contain compounds involved in a number of biochemical pathways, as well as chemicals that test the sensitivity of cells against antibiotics and stress. While the PM experimental workflow is completely automated, statistical methods to analyze and interpret the data are lagging behind. To take full advantage of the technology, it is essential to develop efficient analytical methods to quantify the information in the complex datasets resulting from PM experiments. We propose the use of statistical growth-curve models to rigorously quantify observed differences in PM experiments, in the context of the growth and metabolism of Yersinia pestis cells grown under different physiological conditions. The information from PM experiments complement genomic and proteomic results and can be used to identify gene function and in drug development. Successful coupling of phenomics results with genomics and proteomics will lead to an unprecedented ability to characterize bacterial function at a systems biology level.
Institute of Scientific and Technical Information of China (English)
SUN Zhaogang; ZHANG Manfu
2005-01-01
The secreted alphaherpesvirus glycoprotein G (gG) works differently from other proteins. Analysis of the role of ILTV gG in virus attachment, penetration, direct cell-to-cell spread (CTCS) and the growth curve showed that gG or its antibody had no effect on ILTV attachment and penetration and that the gG antibody reduced the virus plaque size and the one-step growth curve on chicken embryo liver (CEL) cells, but gG did not affect the virus plaque size or the one-step growth curve on CEL cells. Laser scanning confocal microscopy (LSCM) detection showed that ILTV gG is located in the perinuclear region and the membrane of the CEL cells. These results suggested that ILTV gG might contribute to direct cell-to-cell transmission.
Pan, Shoukui; Okano, Y.; Tsunekawa, S.; Fukuda, T.
1993-03-01
The Kyropoulus method was used to grow nonlinear optical organic crystals ABP (4-aminobenzophenone). The crystals were characterized by nonlinear optical measurements and had a large effect of frequency doubling.
Hanumantharao, Redrothu; Kalainathan, S.
2012-02-01
A new and efficient semi organic nonlinear optical crystal (NLO) from the amino acid family L-alanine lithium chloride (LAL) has been grown by slow evaporation technique from aqueous solution. The functional groups were identified from NMR spectral studies. Mass spectral analysis shows the molecular ion mass. Dielectric studies has been done for the grown crystal and relative SHG efficiency is measured by Kurtz and Perry method and found to about 0.43 times that of standard potassium dihydrogen phosphate (KDP) crystals. The compound crystallized in non-centrosymmetric space group Pna21. The results have been discussed in detail.
Hanumantharao, Redrothu; Kalainathan, S
2012-02-01
A new and efficient semi organic nonlinear optical crystal (NLO) from the amino acid family L-alanine lithium chloride (LAL) has been grown by slow evaporation technique from aqueous solution. The functional groups were identified from NMR spectral studies. Mass spectral analysis shows the molecular ion mass. Dielectric studies has been done for the grown crystal and relative SHG efficiency is measured by Kurtz and Perry method and found to about 0.43 times that of standard potassium dihydrogen phosphate (KDP) crystals. The compound crystallized in non-centrosymmetric space group Pna21. The results have been discussed in detail.
Directory of Open Access Journals (Sweden)
Vijayan K. Pillai
2013-01-01
Full Text Available Background. The gross longitudinal relationship between female literacy and maternal mortality ratios has not been adequately investigated even though the knowledge of the relationship is crucial for designing maternal mortality reduction programs through female literacy campaigns and improvements. The objective of the study was to examine the dynamic relationship between female literacy and mortality ratios. A longitudinal study design spanning three decades, 1970–2000, was used. Country level data on 143 nations belonging to six geographical regions for the duration 1970–2000 were secured from websites hosted by global agencies such as World Bank and the United Nations were utilized. Maternal mortality ratios (1970–2000 ranged from 147 to 271 across the six regions. The longitudinal relationship between female literacy rates and maternal mortality ratios was examined using a latent growth curve approach. The study found that rates of change in female literacy and maternal mortality ratios are negatively related. Steady rates of increase in female literacy were associated with declining maternal mortality ratios as well. We find that female literacy programs are of immense value in reducing maternal mortality ratios given their ability to yield sustained reductions in mortality levels in developing countries.
Price, Matthew; Anderson, Page L
2011-11-01
Models of social phobia highlight the importance of anticipatory anxiety in the experience of fear during a social situation. Anticipatory anxiety has been shown to be highly correlated with performance anxiety for a variety of social situations. A few studies show that average ratings of anxiety during the anticipation and performance phases of a social situation decline following treatment. Evidence also suggests that the point of confrontation with the feared stimulus is the peak level of fear. No study to date has evaluated the pattern of anxious responding across the anticipation, confrontation, and performance phases before and after treatment, which is the focus of the current study. Socially phobic individuals (N = 51) completed a behavioral avoidance task before and after two types of manualized cognitive behavioral therapy, and gave ratings of fear during the anticipation and performance phases. Results from latent growth curve analysis were the same for the two treatments and suggested that before treatment, anxiety sharply increased during the anticipation phase, was highly elevated at the confrontation, and gradually increased during the performance phase. After treatment, anxiety increased during the anticipation phase, although at a much slower rate than at pretreatment, peaked at confrontation, and declined during the performance phase. The findings suggest that anticipatory experiences are critical to the experience of fear for public speaking and should be incorporated into exposures.
Directory of Open Access Journals (Sweden)
Christian eGeiser
2013-12-01
Full Text Available Latent state-trait (LST and latent growth curve (LGC models are frequently used in the analysis of longitudinal data. Although it is well-known that standard single-indicator LGC models can be analyzed within either the structural equation modeling (SEM or multilevel (ML; hierarchical linear modeling frameworks, few researchers realize that LST and multivariate LGC models, which use multiple indicators at each time point, can also be specified as ML models. In the present paper, we demonstrate that using the ML-SEM rather than the SL-SEM framework to estimate the parameters of these models can be practical when the study involves (1 a large number of time points, (2 individually-varying times of observation, (3 unequally spaced time intervals, and/or (4 incomplete data. Despite the practical advantages of the ML-SEM approach under these circumstances, there are also some limitations that researchers should consider. We present an application to an ecological momentary assessment study (N = 158 youths with an average of 23.49 observations of positive mood per person using the software Mplus (Muthén & Muthén, 1998-2012 and discuss advantages and disadvantages of using the ML-SEM approach to estimate the parameters of LST and multiple-indicator LGC models.
Gao, Yu; Raine, Adrian; Dawson, Michael E; Venables, Peter H; Mednick, Sarnoff A
2007-11-01
Little is known about the development of the skin conductance orienting response (SCOR) in childhood. This longitudinal study examines the effects of age on initial SCOR, habituation, and reorienting. Skin conductance responses to nonsignal auditory stimuli were recorded from 200 male and female children at five different time points (ages 3, 4, 5, 6, and 8 years). Longitudinal latent growth curve analyses were used to determine the trajectory of each SCOR measure during this period. Results indicated that (a) initial SCOR is present at age 3, increases thereafter to peak at age 6, and then levels off, (b) habituation is absent at age 3, but becomes apparent at age 4 years and increases thereafter with increasing age, (c) SC reorienting is absent from ages 3 to 8, and (d) boys and girls do not exhibit different developmental trajectories. Results suggest that from age 3 to 8 years, the transition from the functionally immature to mature neural network underlying orienting and habituation is a continuous process and may be related to children's cognitive development during this period.
Long-term wave growth and its linear and nonlinear interactions with wind fluctuations
Directory of Open Access Journals (Sweden)
Z. Ge
2008-05-01
Full Text Available Following Ge and Liu (2007, the simultaneously recorded time series of wave elevation and wind velocity are examined for long-term (on Lavrenov's τ_{4}-scale or 3 to 6 h linear and nonlinear interactions between the wind fluctuations and the wave field. Over such long times the detected interaction patterns should reveal general characteristics for the wave growth process. The time series are divided into three episodes, each approximately 1.33 h long, to represent three sequential stages of wave growth. The classic Fourier-domain spectral and bispectral analyses are used to identify the linear and quadratic interactions between the waves and the wind fluctuations as well as between different components of the wave field.
The results show clearly that as the wave field grows the linear interaction becomes enhanced and covers wider range of frequencies. Two different wave-induced components of the wind fluctuations are identified. These components, one at around 0.4 Hz and the other at around 0.15 to 0.2 Hz, are generated and supported by both linear and quadratic wind-wave interactions probably through the distortions of the waves to the wind field. The fact that the higher-frequency wave-induced component always stays with the equilibrium range of the wave spectrum around 0.4 Hz and the lower-frequency one tends to move with the downshifting of the primary peak of the wave spectrum defines the partition of the primary peak and the equilibrium range of the wave spectrum, a characteristic that could not be revealed by short-time wavelet-based analyses in Ge and Liu (2007. Furthermore, these two wave-induced peaks of the wind spectrum appear to have different patterns of feedback to the wave field. The quadratic wave-wave interactions also are assessed using the auto-bispectrum and are found to be especially active during the first and the third episodes. Such directly detected wind-wave interactions, both linear and
R.D. Stoel; T.T.D. Peetsma; J. Roeleveld
2001-01-01
Latent growth curve (LGC) analysis of longitudinal data for pupils' school investment, self confidence and language ability is presented. A multivariate model is tested that relates the three developmental processes to each other and to intelligence. All processes show significant differences betwee
Yerdelen, Sündüs; McCaffrey, Adam; Klassen, Robert M.
2016-01-01
This study investigated the longitudinal association between students' anxiety and procrastination and the relation of self-efficacy for self-regulation to these constructs. Latent Growth Curve Modeling was used to analyze data gathered from 182 undergraduate students (134 female, 48 male) at 4 times during a semester. Our results showed that…
Reitz, Ellen; Prinzie, Peter; Dekovic, Maja; Buist, Kirsten L.
2007-01-01
The purpose of the present study was to examine the direct and indirect effects (through peer contacts) of parental knowledge on adolescents' delinquent and aggressive problem behavior, using latent growth curve modeling. A sample of 457 13- to 14-year old adolescents at first measurement wave (M = 13.27; SD = 0.45 years) filled out questionnaires…
旅游系统非线性成长机制%Study on Tourism System Nonlinear Growth Mechanism
Institute of Scientific and Technical Information of China (English)
吴文智; 赵磊
2012-01-01
本文首先利用系统动力学分析了旅游系统非线性成长的基本形态，发现旅游系统非线性成长基本呈现出s形成长形态，并从旅游系统内外两方面对其进行了详实分析。然后，分别从旅游系统内部旅游者与旅游目的地二元结构之间进行动态演化博弈、对异质性旅游系统之间进行系统协同演化建模两方面，分析了旅游系统非线性成长的动态机制。接着运用面板数据对整体旅游系统、国内旅游者一旅游目的地旅游系统（DTS）和入境旅游者一旅游目的地系统（ITS）进行计量回归分析。实证结果显示，除整体旅游系统外，国内旅游系统和入境旅游系统具有显著的非线性成长经济效应。%Firstly, using system dynamics, this paper analyses nonlinear growth shapes of tourism system, find that tourism system nonlinear growth shows S shape, and carry out a detailed analysis from internal and external tourism system. Then this paper analyses dynamical mechanism of tourism system nonlinear growth from two aspects between dynamical evolutional game of tourist-tourism destination and system emergence models of heterogeneous tourism systems. Finally, using panel data, this paper measure econometric regression analysis for domestic tourist- tourism destination tourism system （DTS） and international tourist-tourism destination tourism system （ITS）, and empirical results shows that aside from complete tourism system, destination tourism system （DTS） and international tourist-tourism destination tourism system （ITS） have significant nonlinear growth economic effects. With the unceasing enhancement of the tourism industry association fusion ability and tourism product production technology, the nonlinear growth of the tourism system in different stages shows different growing form. According to the tourist destination in the life cycle of cognitive prior theory, and the system dynamics analysis of
Non-linear growth: The road ahead for Indian IT outsourcing companies
Directory of Open Access Journals (Sweden)
Y.L.R. Moorthi
2011-09-01
Full Text Available India-centric IT services companies (major among them being the SWITCH companies -- Satyam, Wipro, Infosys, TCS, Cognizant and HCL grew rapidly for more than a decade by providing low cost, high quality business process and IT outsourcing services. With the bigger companies already crossing the 100,000-employee mark, they are now turning their attention to non-linear revenue (i.e. revenue less dependent on the number of employees or greater revenue earned per employee. For this, they need to pursue ‘disruptive’ strategies which are distinctly different from the ‘incremental’ initiatives they adopted in the past to maintain linear revenue. This paper first outlines the disruptive and the incremental initiatives of the SWITCH companies and the road ahead for them. This is followed by an interview with R Chandrasekaran, President and MD, Global Delivery, Cognizant, who discusses Cognizant’s key operating principles – which include customer-centricity, their unique Two-in-a-Box operating model and their emphasis on working together with clients to make their businesses stronger – and how they have contributed to the company’s spectacular growth story.
Zhang, Bingbing; Shi, Guoqiang; Yang, Zhihua; Zhang, Fangfang; Pan, Shilie
2017-03-27
Deep-ultraviolet nonlinear optical (DUV NLO) crystals are the key materials to extend the output range of solid-state lasers to below 200 nm. The only practical material KBe2 BO3 F2 suffers high toxicity through beryllium and strong layered growth. Herein, we propose a beryllium-free material design and synthesis strategy for DUV NLO materials. Introducing the (BO3 F)(4-) , (BO2 F2 )(3-) , and (BOF3 )(2-) groups in borates could break through the fixed 3D B-O network that would produce a larger birefringence without layering and simultaneously keep a short cutoff edge down to DUV. The theoretical and experimental studies on a series of fluorooxoborates confirm this strategy. Li2 B6 O9 F2 is identified as a DUV NLO material with a large second harmonic generation efficiency (0.9×KDP) and a large predicted birefringence (0.07) without layering. This study provides a feasible way to break down the DUV wall for NLO materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Energy Technology Data Exchange (ETDEWEB)
Yadav, Harsh [Crystal Lab, Department of Physics & Astrophysics, University of Delhi, Delhi 110007 (India); Sinha, Nidhi [Department of Physics & Electronics, SGTB Khalsa College, University of Delhi, Delhi 110007 (India); Kumar, Binay, E-mail: b3kumar69@yahoo.co.in [Crystal Lab, Department of Physics & Astrophysics, University of Delhi, Delhi 110007 (India)
2015-04-15
Highlights: • A new semiorganic single crystal of LSO grown by slow evaporation technique. • Morphological studies of the LSO crystal deduced by BFDH law. • In the UV–vis spectrum wide transparent region and large band gap were found. • SHG is equal to KDP crystal and d{sub 33} was found to be equal to 6pC/N. • Grown crystal belongs to softer category. - Abstract: New semiorganic crystal of lithium sulfate monohydrate oxalate (LSO) for nonlinear application was synthesized by controlled slow evaporation method. The growth rate of various planes of the grown crystal was estimated by morphological study. Single crystal XRD analysis confirmed that the crystal belongs to triclinic lattice with space group P1. High transparency (∼95%) with large band gap (4.57 eV) was analyzed by UV–vis studies. FTIR and Raman spectroscopy were used to identify various functional groups present in the LSO crystal. SHG efficiency was found to be equal to the KDP crystal. Thermal stability (up to 117.54 °C) and melting point (242 °C) of the crystal were studied by TG-DTA. In dielectric measurements, the value of dielectric constant decreases with increase in frequency. Hardness studies confirmed soft nature of crystals. The piezoelectric coefficient was found to be 6pC/N along [0 0 1].
Nath, Sujit K
2016-01-01
We investigate the evolution of hydromagnetic perturbations in a small section of accretion disks. It is known that molecular viscosity is negligible in accretion disks. Hence, it has been argued that Magnetorotational Instability (MRI) is responsible for transporting matter in the presence of weak magnetic field. However, there are some shortcomings, which question effectiveness of MRI. Now the question arises, whether other hydromagnetic effects, e.g. transient growth (TG), can play an important role to bring nonlinearity in the system, even at weak magnetic fields. Otherwise, whether MRI or TG, which is primarily responsible to reveal nonlinearity to make the flow turbulent? Our results prove explicitly that the flows with high Reynolds number (Re), which is the case of realistic astrophysical accretion disks, exhibit nonlinearity by best TG of perturbation modes faster than that by best modes producing MRI. For a fixed wavevector, MRI dominates over transient effects, only at low Re, lower than its value ...
Busscher, Iris; Wapstra, Frits Hein; Veldhuizen, Albert G.
2010-01-01
Background: Scoliosis is present in 3-5% of the children in the adolescent age group, with a higher incidence in females. Treatment of adolescent idiopathic scoliosis is mainly dependent on the progression of the scoliotic curve. There is a close relationship between curve progression and rapid (spi
Directory of Open Access Journals (Sweden)
Juliana Sampaio Guedes Gomiero
2009-06-01
Full Text Available Conduziu-se um experimento no setor de piscicultura da Universidade Federal de Lavras M.G., com o objetivo de estabelecer curvas de crescimento morfométrico em função do peso corporal para a piracanjuba (Brycon orbignyanus. Alevinos de piracanjuba foram cultivados em viveiros de terra e alimentados com ração comercial até atingirem peso aproximado de 1 kg. Durante o período experimental realizaram-se amostragens aleatórias, onde foram avaliadas as medidas morfométricas comprimento da cabeça (CCAB, comprimento padrão (CP, altura (AND e largura (LND tomada no 1ºraio da nadadeira dorsal e as razões morfométricas (CCAB/CP, AND/CP, LND/CP, AND/LND utilizando-se as funções de Brody, von Bertalanffy, Gompertz e Logística. As funções estudadas apresentaram bom ajuste para todas as medidas morfométricas e para a razão CCAB/CP. As funções de Brody, von Bertalanffy e Gompertz apresentaram qualidades de ajuste semelhantes e superiores à função Logística para as medidas morfométricas. Para a razão CCAB/CP a função Logística apresentou-se superior às demais. A taxa de crescimento da CCAB e LND foi superior às do CP e AND, indicando um crescimento mais rápido da cabeça e largura do que do comprimento padrão e altura. Conclui-se que todos os modelos estudados apresentaram bom ajuste, sendo o de Brody e o de von Bertalanffy os que descrevem melhor o crescimento morfométrico da piracanjuba.An experiment was carried out at the fish farming sector of the Universidade Federal de Lavras M.G., with the objective of establishing morphometric growth curves as a function of the body weight of piracanjuba (Brycon orbignyanus. Fingerlings of piracanjuba were cultivated in earthen ponds and fed a commercial diet (ad libitum until they reached weight of about 1 kg. During the experimental period, samplings were randomly selected to take morphometric measures of the head length (CCAB, standard length (CP, height (AND, and breadth (LND
Hanumantharao, Redrothu; Kalainathan, S.; Bhagavannarayana, G.
2012-06-01
Single crystals of organic nonlinear material urea thiosemicarbazone monohydrate (UTM) have been grown by slow evaporation method. The grown crystals were characterized by single crystal X-ray diffraction analysis reveals that sample crystallized in triclinic system with noncentrosymmetric space group P1. Powder XRD pattern confirmed that grown crystal posses highly crystalline nature. FTIR spectrum was recorded to identify the presence of functional groups and molecular structure was confirmed by 1H NMR spectrum. Material confirmation of title compound has been performed by using mass spectroscopic analysis. Elemental composition of grown crystal was confirmed by energy-dispersive spectrometry (EDS). To study the crystalline perfection of the grown crystals, high-resolution X-ray diffraction (HR-XRD) study was carried out. Thermogravimetric and differential thermal analyses were employed to understand the thermal and physio-chemical stability of the synthesized compound. UV-Vis-NIR spectrum revealed the transmission properties of the crystal specimen. Relative SHG efficiency is measured by Kurtz and Perry method and found to about 0.89 times that of standard potassium dihydrogen phosphate (KDP) crystals.
Relation between Crack Growth Rate Curve and S- N Curve for Metal Fatigue%金属疲劳裂纹扩展率曲线与S-N曲线之间的关系
Institute of Scientific and Technical Information of China (English)
崔维成
2002-01-01
Currently two different theories for predicting the fatigue life of metal structures are used.One is the cumulative fatigue damage(CFD) theory based mainly on S- N (or ε - N) curves and the other is the fatigue crack propagation (FCP) theory based on the crack growth rate curve.If the failure is defined as the final fracture of a component,then both S- N curves and crack growth rate curves reflect the fundamental material behavior under fatigue loading.Some relations must exist between them although they were tested separately in the past.The purpose of this paper is to discuss such a relation.Based on the general formats of an S- N curve and a representative crack growth rate curve,a formal relation is established between the two types of curves.This indicates that only one type of curves needs to be tested and the other can be derived from the existing test results.An example of a center crack in a plate of finite width is used to demonstrate how to convert one set of material parameters to another.%目前有两种不同的理论用于预报金属结构的疲劳寿命.一种是基于S-N曲线的累积疲劳损伤理论,另一种是基于裂纹扩展率曲线的疲劳裂纹扩展理论.如果都把一个构件的最终断裂作为疲劳破坏的定义,则S-N曲线和裂纹扩展率曲线均是反映金属在疲劳载荷作用下的基本材料特性.尽管在过去这两种曲线是分别测试的,但它们之间应该存在一些相互关系.本文的主要目的就是讨论它们之间的关系.基于S-N曲线的一个一般表达式和裂纹扩展率曲线的一个有代表性的表达式,本文建立了两种曲线之间的一个正式关系,这表明只需要测试一种曲线,而另一种曲线就可以根据已有的试验结果导出.文章以一个中央裂纹平板作为例子,演示了如何根据一种曲线推导另一种曲线.
Pandian, Muthu Senthil; Karuppasamy, P.; Ramasamy, P.
2017-05-01
The semi-organic nonlinear optical single crystals of potassium 3,5-dinitrobenzoate (KDNB) were grown by slow evaporation solution technique (SEST). The lattice parameters of the grown crystal were confirmed by single crystal X-ray diffraction analysis. The optical transmittance, cut-off wavelength and band gap of the KDNB crystal were obtained by UV-Vis NIR spectrum analysis. Vickers microhardness analysis was carried out to identify mechanical stability and work hardening co-efficient of the grown crystal. The crystalline perfection of the grown crystal was identified by chemical etching study using water as etchant. The third-order nonlinear optical properties such as nonlinear refractive index (n2), nonlinear absorption co-efficient (β) and third order nonlinear susceptibility (χ(3)) of KDNB crystal were evaluated using Z-scan technique at the wavelength of 632.8 nm.
Johansson; Aubry
2000-05-01
We investigate the long-time evolution of weakly perturbed single-site breathers (localized stationary states) in the discrete nonlinear Schrodinger equation. The perturbations we consider correspond to time-periodic solutions of the linearized equations around the breather, and can be either (i) spatially localized or (ii) spatially extended. For case (i), which corresponds to the excitation of an internal mode of the breather, we find that the nonlinear interaction between the breather and its internal mode always leads to a slow growth of the breather amplitude and frequency. In case (ii), corresponding to interaction between the breather and a standing-wave phonon, the breather will grow provided that the wave vector of the phonon is such that the generation of radiating higher harmonics at the breather is possible. In other cases, breather decay is observed. This condition yields a limit value for the breather frequency above which no further growth is possible. We also discuss another mechanism for breather growth and destruction which becomes important when the amplitude of the perturbation is non-negligible, and which originates from the oscillatory instabilities of the nonlinear standing-wave phonons.
Keen, A.; Smits, T.F.C.
1989-01-01
Een functie is voorgesteld die de groeisnelheid van de imperfecte schimmel Sphaeropsis sapinea in relatie tot de temperatuur beschrijft. De functie bevat drie vrije parameters, die de maximale groeisnelheid, de optimum temperatuur en de vorm van de curve representeren
Parameters for efficient growth of second harmonic field in nonlinear photonic crystals
Energy Technology Data Exchange (ETDEWEB)
Joseph, Shereena, E-mail: sherin5462@gmail.com; Khan, Mohd. Shahid; Hafiz, Aurangzeb Khurram
2014-03-01
The ultrashort pulse propagation and nonlinear second harmonic generation under the undepleted pump approximation in a quadratic nonlinear photonic crystal (NPC) structure is theoretically investigated and the optimized parameters for high second harmonic generation conversion efficiency are extracted. The transfer matrix method is used for the numerical formulation for oblique angle of incidence. A unique set of material combination GaInP/InAlP is selected as alternating nonlinear and linear layers. The NPC parameters like incident angle and layer thickness are manipulated to obtain the exact phase matching using double resonance condition for a fixed number of layers with known experimental material parameters.
欧拉型藏羊生长发育曲线模型预测及趋势分析%Growth Curve Model Prediction and Trend Analysis of Oula Tibetan Sheep
Institute of Scientific and Technical Information of China (English)
王宏博; 梁春年; 包鹏甲; 朱新书; 阎萍
2016-01-01
试验旨在研究欧拉型藏羊的生长发育状况，初步探讨欧拉型藏羊的生长发育曲线理论模型并找出欧拉型藏羊养殖的最佳生长点，以期为欧拉型藏羊的选育和饲养管理的改善提供理论依据。选用甘肃省甘南玛曲县欧拉乡牧户的欧拉型藏羊羔羊60只，测定了0（初生）、2、7、14、21、28、42、56、70、84、98、112日龄的体重、体高和体长。采用Logistic、Richards、Exponential Association和Gompertz Relation 4种生长曲线模型对欧拉型藏羊羔羊的生长曲线进行拟合。结果发现：Richards曲线模型最适宜描述欧拉型藏羊体重增长模式，Exponential Association是拟合欧拉型藏羊羔羊体高和体长早期生长过程的最优模型。%This paper aimed to study the growth and development of Oula Tibetan sheep,and make a preliminary discussion on growth curve model and a trend analysis for improving the Oula Tibetan sheep breeding and the feeding management. 60 grazing Oula Tibetan sheep were chosen and the weight,height and body length of newborn,2-day-old,7-day-old,14-day-old,21-day-old,28-day-old,42-day-old,56-day-old,70-day-old,84-day-old,98-day-old,112-day-old were measured. The growth curves of Oula Tibetan sheep were analyzed with four kinds of nonlinear models(Logistics,Richards,Exponential Association and Gompertz Relation). The results showed that the growth curves were appropriately fitted with Richards and Exponential Association.
Zhang, Chen; Wang, Yuan; Song, Xiaowei; Kubota, Jumpei; He, Yanmin; Tojo, Junji; Zhu, Xiaodong
2017-12-31
This paper concentrates on a Chinese context and makes efforts to develop an integrated process to explicitly elucidate the relationship between economic growth and water pollution discharge-chemical oxygen demand (COD) discharge and ammonia nitrogen (NH3-N), using two unbalanced panel data sets covering the period separately from 1990 to 2014, and 2001 to 2014. In our present study, the panel unit root tests, cointegration tests, and Granger causality tests allowing for cross-sectional dependence, nonstationary, and heterogeneity are conducted to examine the causal effects of economic growth on COD/NH3-N discharge. Further, we simultaneously apply semi-parametric fixed effects estimation and parametric fixed effects estimation to investigate environmental Kuznets curve relationship for COD/NH3-N discharge. Our empirical results show a long-term bidirectional causality between economic growth and COD/NH3-N discharge in China. Within the Stochastic Impacts by Regression on Population, Affluence and Technology framework, we find evidence in support of an inverted U-shaped curved link between economic growth and COD/NH3-N discharge. To the best of our knowledge, there have not been any efforts made in investigating the nexus of economic growth and water pollution in such an integrated manner. Therefore, this study takes a fresh look on this topic. Copyright © 2017 Elsevier B.V. All rights reserved.
Tassev, V. L.; Vangala, S.; Peterson, R.; Kimani, M.; Snure, M.; Markov, I.
2016-03-01
Frequency conversion in orientation-patterned quasi-phase matched materials is a leading approach for generating tunable mid- and long-wave coherent IR radiation for a wide variety of applications. A number of nonlinear optical materials are currently under intensive investigation. Due to their unique properties, chiefly wide IR transparency and high nonlinear susceptibility, GaAs and GaP are among the most promising. Compared to GaAs, GaP has the advantage of having higher thermal conductivity and significantly lower 2PA in the convenient pumping range of 1- 1.7 μm. HVPE growth of OPGaP, however, has encountered certain challenges: low quality and high price of commercially available GaP wafers; and strong parasitic nucleation during HVPE growth that reduces growth rate and aggravates layer quality, often leading to pattern overgrowth. Lessons learned from growing OPGaAs were not entirely helpful, leaving us to alternative solutions for both homoepitaxial growth and template preparation. We report repeatable one-step HVPE growth of up to 400 μm thick OPGaP with excellent domain fidelity deposited for first time on OPGaAs templates. The templates were prepared by wafer fusion bonding or MBE assisted polarity inversion technique. A close to equilibrium growth at such a large lattice mismatch (-3.6%) is itself noteworthy, especially when previously reported attempts (growth of OPZnSe on OPGaAs templates) at much smaller mismatch (+0.3%) have produced limited results. Combining the advantages of the two most promising materials, GaAs and GaP, is a solution that will accelerate the development of high power, tunable laser sources for the mid- and long-wave IR, and THz region.
Tassev, V.; Snure, M.; Vangala, S.; Kimani, M.; Peterson, R.; Schunemann, P.
2014-10-01
A series of nonlinear materials including GaAs, GaP, and ZnSe have been examined to determine their suitability for non-linear frequency conversion devices (FCD) and more specifically their use as high power, compact and broadly tunable IR and THz sources for defense and security applications. The more mature GaAs was investigated to reveal the causes for the optical losses that restrict achievement of higher conversion efficiency in quasi-phasematched FCD, while the efforts with GaP were oriented in developing simple, cost effective techniques for fabrication of orientation patterned (OP) templates and optimizing the subsequent thick HVPE growth on these templates. Thus, average growth rates of 50- 70 μm/h were achieved in up to 8-hour long experiments. High optical layer quality was achieved by suitable control of the process parameters. The optimal orientation of the pattern was determined and used as essential feedback aiming to improve the template preparation. This led to the production of the first 300-400 μm thick device quality OPGaP. Efforts to suppress the parasitic nucleation during growths with longer duration or to achieve thicker layers by a 2 step growth process were also made. The main challenge with the newer candidate, OPZnSe, was to establish suitable regimes for hydrothermal growth on plain (001) ZnSe seeds grown by chemical vapor deposition. Two different temperature ranges, 330-350 °C and 290-330 °C, were investigated. The mineralized concentration was also manipulated to accelerate the growth in (111) direction and, thus, to improve the growth in (001) direction. The next material in the line is GaN. The traditional HVPE approach will be combined with a growth at low reactor pressure. Growths will be performed in the next sequence: growth on thin GaN layers grown by MOCVD on sapphire wafers, growth on half-patterned GaN templates with different orientations and, finally, growth on OPGaN templates.
Georgiev, E.S.; Mihaylov, E.S.
2015-01-01
This paper tests the Environmental Kuznets Curve (EKC) hypothesis for four local (SOx, NOx , CO, VOC) and two global (CO2, GHG) air pollutants. Using a panel data set of thirty OECD countries, the paper finds that the postulated inverted U-shaped relationship between income and pollution does not ho
Shen, Linyuan; Luo, Jia; Du, Jingjing; Liu, Chendong; Wu, Xiaoqian; Pu, Qiang; Fu, Yuhua; Tang, Qianzi; Liu, Yuanrui; Li, Qiang; Yang, Runlin; Li, Xuewei; Tang, Guoqing; Jiang, Yanzhi; Li, Mingzhou; Zhang, Shunhua; Zhu, Li
2015-01-01
Animal growth curves can provide essential information for animal breeders to optimize feeding and management strategies. However, the genetic mechanism underlying the phenotypic differentiation between the inflection point and asymptotic stages of the growth curve is not well characterized. Here, we employed Liangshan pigs in stages of growth at the inflection point (under inflection point: UIP) and the two asymptotic stages (before the inflection point: BIP, after the inflection point: AIP) as models to survey global gene expression in the longissimus dorsi muscle using digital gene expression (DGE) tag profiling. We found Liangshan pigs reached maximum growth rate (UIP) at 163.6 days of age and a weight of 134.6 kg. The DGE libraries generated 117 million reads of 5.89 gigabases in length. 21,331, 20,996 and 20,139 expressed transcripts were identified BIP, UIP and AIP, respectively. Among them, we identified 757 differentially expressed genes (DEGs) between BIP and UIP, and 271 DEGs between AIP and UIP. An enrichment analysis of DEGs proved the immune system was strengthened in the AIP stage. Energy metabolism rate, global transcriptional activity and bone development intensity were highest UIP. Meat from Liangshan pigs had the highest intramuscular fat content and most favorable fatty acid composition in the AIP. Three hundred eighty (27.70%) specific expression genes were highly enriched in QTL regions for growth and meat quality traits. This study completed a comprehensive analysis of diverse genetic mechanisms underlying the inflection point and asymptotic stages of growth. Our findings will serve as an important resource in the understanding of animal growth and development in indigenous pig breeds.
Synthesis, growth and characterization of π conjugated organic nonlinear optical chalcone derivative
Energy Technology Data Exchange (ETDEWEB)
Prabhu, A.N., E-mail: ashwatha.prabhu@manipal.edu [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576 104 (India); Upadhyaya, V. [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576 104 (India); Jayarama, A., E-mail: jayaram@mite.ac.in [Department of Physics, Mangalore Institute of Technology and Engineering (MITE), Moodabidri 574225 (India); Subrahmanya Bhat, K. [Department of Chemistry, Manipal Institute of Technology, Manipal University, Manipal 576 104 (India)
2013-02-15
A new potentially useful nonlinear optical organic material, 1-(5-chlorothiophen-2-yl)-3-(2,3-dimethoxyphenyl)prop-2-en-1-one, has been synthesized and grown as a high-quality single crystal by the slow evaporation technique. The grown crystals were characterized by FT-IR, NMR, thermal analysis, and UV–visible spectroscopy. The material is thermally stabile up to 111 °C. The mechanical property of the grown crystals was studied using Vickers microhardness tester and the load dependence hardness was observed. The third order nonlinear optical properties of the material such as real and imaginary part of χ{sup (3)}, nonlinear absorption coefficient and nonlinear refractive index were determined using nanosecond laser pulses at 532 nm wavelength by employing Z-scan technique. The nonlinear refractive index is found to be of the order of 10{sup −11} cm{sup 2} W{sup −1}. The magnitude of third order susceptibility is of the order of 10{sup −13} esu. The observed increase in the third order nonlinearity in these molecules clearly indicates the electronic origin. The compounds exhibit good optical limiting at 532 nm. The best optical limiting behavior of this molecule is due to the substituted strong electron donor. - Highlights: ► A novel thiophene substituted NLO crystal has been grown using methanol as solvent. ► The crystals were characterized by using FTIR, TGA/DTA and UV–visible spectroscopy. ► The n{sub 2} and χ{sup (3)} values is of the order of 10{sup −11} cm{sup 2} W{sup −1} and 10{sup −13} esu respectively. ► The crystals show better optical limiting behavior.
Directory of Open Access Journals (Sweden)
Streck Nereu Augusto
2003-01-01
Full Text Available Temperature is a major factor that affects metabolic processes in living organisms. Thermal time has been widely used to account for the effects of temperature on crop growth and development. However, the thermal time approach has been criticized because it assumes a linear relationship between the rate of crop growth or development and temperature. The response of the rate of crop growth and development to temperature is nonlinear. The objective of this study was to develop a generalized nonlinear temperature response function for some growth and developmental parameters in kiwifruit (Actinidia deliciosa (A. Chev. C. F. Liang & A. R. Ferguson. The nonlinear function has three coefficients (the cardinal temperatures, which were 0ºC, 25ºC, and 40ºC. Data of temperature response of relative growth rate, relative leaf area growth, net photosynthesis rate, and leaf appearance rate in kiwifruit (female cv. Hayward at two light levels, which are from published research, were used as independent data for evaluating the performance of the nonlinear and the thermal time functions. The results showed that the generalized nonlinear response function is better than the thermal time approach, and the temperature response of several growth and developmental parameters in kiwifruit can be described with the same response function.
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Marina Piria
2011-12-01
Full Text Available The rudd is a cyprinid herbivorous freshwater fish. The samples of rudd have been taken from the „Ključić brdo“ location. The arithmetic mean of length for each age group was determined according to Peterson, Danish ichthyologist. As back calculation of average length of some populations was done by von Bertalanffy growth function (VBGF Lt=L∞ (1-e-K(t-t0, the equation could be expressed by the following formula Lt=17.82 (1-e-1.0431(t-0.579. The von Bertalanffy growth function is helpful because its parameters help in comparing different fish populations. According to growth and age, the rudd has been divided in four age groups. The first group represents the youngest fish with average growth of L1=11.603 cm, the second group L2=15.921 cm, the third group L3=19.295 cm while the average growth of the fourth group, the oldest one, was L4=19.998 cm. The growth of rudd at a chosen location has been compared to the already published data of rudd growing at other locations. Growth performance at chosen location was around 5 which coincides with the data taken from the literature. This research proves that investigated water of the „Ključić brdo“ location is favourable for the growth and the development of rudd.
Energy Technology Data Exchange (ETDEWEB)
Dhanalakshmi, B. [Department of Physics, Asan Memorial College of Engineering and Technology, Chengalpattu 603 203, Tamil Nadu (India); Ponnusamy, S., E-mail: suruponnus@gmail.com [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603 203, Tamil Nadu (India); Muthamizhchelvan, C.; Subhashini, V. [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603 203, Tamil Nadu (India)
2015-10-15
Highlights: • EDA4NPH crystal possesses negative nonlinear refractive index. • The crystal exhibits high third-order NLO susceptibility. • Wide transparency of the crystal makes it suitable for NLO applications. • Dielectric studies substantiate the suitability for electro-optic applications. • The crystal possesses suitable mechanical strength for device fabrication. - Abstract: Bulk crystals of the charge-transfer complex, ethylenediamine-4-nitrophenolate monohydrate, were grown by slow solvent evaporation method from aqueous solution at room temperature. The X-ray diffraction measurements showed that the crystal belongs to centrosymmetric space group C2/c of monoclinic system. The functional groups in the complex were identified using FTIR, FTRaman and FTNMR analyses. The Z-scan measurements revealed the negative nonlinear refractive index of the crystal. The nonlinear absorption coefficient and third order nonlinear optical susceptibility calculated from the measurements were −3.5823 × 10{sup −3} cm/W and 2.3762 × 10{sup −6} esu respectively. The crystal was shown to be highly transparent above 366 nm by UV–vis spectroscopy and a yellow fluorescence was observed from PL spectrum. The TG–DTA and DSC analyses showed that the crystal is thermally stable up to 117.4 °C. The crystals were characterized by dielectric, etching and microhardness studies.
Energy Technology Data Exchange (ETDEWEB)
Doroshkevich, A.G.; Zel' dovich, Y.B.; Syunyaev, R.A.; Khlopov, M.Y.
1980-07-01
A discussion is given of the influence that a finite rest mass for the neutrino would have on the phenomenon of ''missing mass'' in galaxies and clusters of galaxies, on the nonlinear stage in the evolution of primordial irregularities, and on the problem of observing neutral hydrogen in the spectrum of distant quasars.
Vijayalakshmi, A.; Vidyavathy, B.; Vinitha, G.
2016-08-01
Isonicotinamide p-nitrophenol (ICPNP), a new organic material, was synthesized using methanol solvent. Single crystals of ICPNP were grown using a slow evaporation solution growth technique. Crystal structure of ICPNP is elucidated by single crystal X-ray diffraction analysis. It belongs to monoclinic crystal system with space group of P21/c. It forms two dimensional networks by O-H…O, N-H…O and C-H…O hydrogen bonds. The molecular structure of ICPNP was further confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical transmittance range and the lower cut-off wavelength (421 nm) with the optical band gap (2.90 eV) of the ICPNP crystal were determined by UV-vis-NIR spectral study. Thermal behavior of ICPNP was studied by thermo gravimetric and differential thermal analyses (TG/DTA). The relative dielectric permittivity was calculated for various temperature ranges. Laser damage threshold of ICPNP crystal was found to be 1.9 GW/cm2 using an Nd:YAG laser. A Z-scan technique was employed to measure the nonlinear absorption coefficient, nonlinear refractive index and nonlinear optical susceptibility. Optical limiting behavior of ICPNP was observed at 35 mW input power.
生长曲线模型的惩罚最小二乘估计%Penalized Least Squares Estimation of Growth Curve Model
Institute of Scientific and Technical Information of China (English)
高采文; 朱晓琳; 曾林蕊
2014-01-01
主要考虑了生长曲线模型中的参数矩阵的估计。首先基于 Potthoff-Roy变换后的生长曲线模型,采用不同的惩罚函数：Hard Thresholding函数,LASSO,ENET,改进 LASSO,SACD给出了参数矩阵的惩罚最小二乘估计。接着对不做变换的生长曲线模型,直接定义其惩罚最小二乘估计,基于Nelder-Mead法给出了估计的数值解算法。最后对提出的参数估计方法进行了数据模拟。结果表明自适应LASSO在估计方面效果比较好。%This paper studied the estimation of parameter matrix in the growth curve model.Based on the Potthoff-Roy transform of the growth curve model,and by using different penalty functions:Hard Thresholding function,LASSO, ENET,LASSO,SACD,the penalized least estimation of parameter matrix was given.Then the penalized least squares estima-tion was defined directly on the growth curve model.The numerical solution algorithm for the estimation was proposed based on the Nelder-Mead method.Finally,the methods for the parameter estimation were simulated.The results show that the a-daptive LASSO is better in the estimation results.
Anbuchezhiyan, M.; Ponnusamy, S.; Muthamizhchelvan, C.
2010-02-01
Single crystal of a new semiorganic nonlinear optical material, L-cystine dihydrobromide, was grown successfully from aqueous solution by slow evaporation method. The grown crystals were characterized by single crystal X-ray diffraction technique to determine the cell parameters. Powder X-ray diffraction analysis also confirms the structure of the grown title compound. The functional groups and vibrational frequencies have been identified using FTIR and FT Raman spectral data. Transmittance of the title compound was analyzed using UV-Vis spectrum. The mechanical strength of the grown crystal was found using Vickers microhardness measurement. The thermal stability of the grown crystal was determined with the aid of thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). Second order nonlinear optical behavior of the grown crystal has been confirmed by Kurtz powder second harmonic generation (SHG) test and its SHG efficiency was found as deff=0.38 deff (KDP).
Energy Technology Data Exchange (ETDEWEB)
Anbuchezhiyan, M. [Department of Physics, Valliammai Engineering College, S.R.M. Nagar, Kattankulathur 603 203, Chennai (India); Ponnusamy, S., E-mail: suruponnus@gmail.co [Centre for Material Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603 203, Chennai (India); Muthamizhchelvan, C. [Centre for Material Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603 203, Chennai (India)
2010-02-15
Single crystal of a new semiorganic nonlinear optical material, L-cystine dihydrobromide, was grown successfully from aqueous solution by slow evaporation method. The grown crystals were characterized by single crystal X-ray diffraction technique to determine the cell parameters. Powder X-ray diffraction analysis also confirms the structure of the grown title compound. The functional groups and vibrational frequencies have been identified using FTIR and FT Raman spectral data. Transmittance of the title compound was analyzed using UV-Vis spectrum. The mechanical strength of the grown crystal was found using Vickers microhardness measurement. The thermal stability of the grown crystal was determined with the aid of thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). Second order nonlinear optical behavior of the grown crystal has been confirmed by Kurtz powder second harmonic generation (SHG) test and its SHG efficiency was found as d{sub eff}=0.38d{sub eff} (KDP).
Non-linear growth: The road ahead for Indian IT outsourcing companies
Directory of Open Access Journals (Sweden)
Y.L.R. Moorthi
2011-06-01
Full Text Available Indian IT outsourcing companies (major among them being the SWITCH companies -- Satyam, Wipro, Infosys, TCS, Cognizant and HCL grew rapidly for more than a decade on low cost business process and IT outsourcing. With the bigger companies already reaching a high of 100,000 employees, they are now turning their attention to non-linear revenue (i.e. revenue less dependent on numbers or greater revenue earned per employee. For this they need to pursue ‘disruptive’ strategies which are distinctly different from the ‘incremental’ initiatives they adopted in the past to maintain linear revenue. This paper first outlines the disruptive and the incremental initiatives of the SWITCH companies and the road ahead for them. This is followed by an interview with S Gopalakrishnan, CEO and MD, Infosys Technologies who discusses the non-linear initiatives of the company and the challenges it faces in the field.
Growth and characterization of organic nonlinear optical single crystal 2,7-dihydroxy naphthalene
Sadhasivam, S.; Rajesh, N. P.
2017-08-01
The organic nonlinear optical crystals of 2,7-dihydroxy naphthalene (2,7-DN) were grown by slow evaporation method using acetone as a solvent. Optically transparent single crystal with sizes up to 15 × 7 × 4 mm3 were grown. Non-centrosymmetry has been studied using X-ray diffraction (XRD) and functional group of 2,7-DN were studied by Raman scattering and FTIR spectral analysis. The optical transmittance was characterized and to be 28%. The melting point of 2,7-DN is 465 K. 2,7-DN found exhibit low dielectric constant of 20-22 in the frequency range of 10 Hz-10 MHz at room temperature. The nonlinear optical and phase matching properties were characterized by Kurtz powder second harmonic generation (SHG) efficiency test.
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Hao Xu
Full Text Available An individual-tree diameter growth model was developed for Cunninghamia lanceolata in Fujian province, southeast China. Data were obtained from 72 plantation-grown China-fir trees in 24 single-species plots. Ordinary non-linear least squares regression was used to choose the best base model from among 5 theoretical growth equations; selection criteria were the smallest absolute mean residual and root mean square error and the largest adjusted coefficient of determination. To account for autocorrelation in the repeated-measures data, we developed one-level and nested two-level nonlinear mixed-effects (NLME models, constructed on the selected base model; the NLME models incorporated random effects of the tree and plot. The best random-effects combinations for the NLME models were identified by Akaike's information criterion, Bayesian information criterion and -2 logarithm likelihood. Heteroscedasticity was reduced with two residual variance functions, a power function and an exponential function. The autocorrelation was addressed with three residual autocorrelation structures: a first-order autoregressive structure [AR(1], a combination of first-order autoregressive and moving average structures [ARMA(1,1] and a compound symmetry structure (CS. The one-level (tree NLME model performed best. Independent validation data were used to test the performance of the models and to demonstrate the advantage of calibrating the NLME models.
Institute of Scientific and Technical Information of China (English)
Yonghan CHOI; Joowan KIM; Dong-Kyou LEE
2012-01-01
In this study,singular vectors related to a heavy rainfall case over the Korean Peninsula were calculated using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) adjoint modeling system.Tangent linear and adjoint models include moist physical processes,and a moist basic state and a moist total energy norm were used for the singular-vector calculations.The characteristics and nonlinear growth of the first singular vector were analyzed,focusing on the relationship between the basic state and the singular vector.The horizontal distribution of the initial singular vector was closely related to the baroclinicity index and the moisture availability of the basic state.The temperature-component energy at a lower level was dominant at the initial time,and the kinetic energy at upper levels became dominant at the final time in the energy profile of the singular vector.The nonlinear growth of the singular vector appropriately reflects the temporal variations in the basic state.The moisture-component energy at lower levels was dominant at earlier times,indicating continuous moisture transport in the basic state.There were a large amount of precipitation and corresponding latent heat release after that period because the continuous moisture transport created favorable conditions for both convective and nonconvective precipitation.The vertical propagation of the singular-vector energy was caused by precipitation and the corresponding latent heating in the basic state.
Saravanan, M.
2016-08-01
The crystals (dimethyl amino pyridinium 4-nitrophenolate 4-nitrophenol [DMAPNP] suitable for NLO applications were grown by the slow cooling method. The solubility and metastable zone width measurement of DMAPNP specimen was studied. The material crystallizes in the orthorhombic crystal system with noncentrosymmetric space group of P212121. The ocular precision in the intact visible region was found to be good for non-linear optical claim. Quality of the grown crystal is ascertained by the HRXRD and etching studies. Laser Damage Threshold and Photoluminescence studies designate that the grown crystal contains less imperfection. The mechanical behaviour of DMAPNP sample at different temperatures was investigated to determine the hardness stability of the grown specimen. The piezoelectric temperament and the relative Second Harmonic Generation (for diverse particle sizes) of the material were also studied. The third order nonlinear optical properties of DMAPNP crystals were premeditated by Z-scan method. Birefringence and optical homogeneity of the crystal were evaluated using modified channel spectrum method. The half wave voltage of the grown crystal deliberate from the elector optic experimentation. Photoconductivity measurement specified consummate of inducing dipoles owing to brawny incident radiation and also disclose the nonlinear activities of the grown specimen.
Schwarz, L.K.; Runge, M.C.
2009-01-01
Age estimation of individuals is often an integral part of species management research, and a number of ageestimation techniques are commonly employed. Often, the error in these techniques is not quantified or accounted for in other analyses, particularly in growth curve models used to describe physiological responses to environment and human impacts. Also, noninvasive, quick, and inexpensive methods to estimate age are needed. This research aims to provide two Bayesian methods to (i) incorporate age uncertainty into an age-length Schnute growth model and (ii) produce a method from the growth model to estimate age from length. The methods are then employed for Florida manatee (Trichechus manatus) carcasses. After quantifying the uncertainty in the aging technique (counts of ear bone growth layers), we fit age-length data to the Schnute growth model separately by sex and season. Independent prior information about population age structure and the results of the Schnute model are then combined to estimate age from length. Results describing the age-length relationship agree with our understanding of manatee biology. The new methods allow us to estimate age, with quantified uncertainty, for 98% of collected carcasses: 36% from ear bones, 62% from length.
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Marcelo Maia Pereira
2014-12-01
Full Text Available Knowledge of the growth of animals is important so that zootechnical activity can be more accurate and sustainable. The objective of this study was to describe the live weight, development of liver tissue and fat body, leg growth, and cumulative food intake of bullfrogs during the fattening phase using nonlinear models. A total of 2,375 bullfrog froglets with an initial weight of 7.03 ± 0.16 g were housed in five fattening pens (12 m². Ten samplings were performed at intervals of 14 days to obtain the variables studied. These data were used to estimate the parameters of Gompertz and logistic models as a function of time. The estimated values of weight (Wm and food intake (FIm at maturity and time when the growth rate is maximum (t* were closer to expected values when the logistic model was used. The Wm values for live weight and liver, adipose and leg weights and the FIm value for food intake were 343.7, 15.7, 19.6, 96.03 and 369.3 g, respectively, with t* at 109, 98, 105, 109 and 107 days. Therefore, the logistic model was the best model to estimate the growth and food intake of bullfrogs during the fattening phase.
Gutiierrez, Gabriel; Vanderwood, Mike L.
2013-01-01
The literacy growth of 260 second-grade English learners (ELs) with varying degrees of English language proficiency (e.g., Beginning, Early Intermediate, Intermediate, Early Advanced and Advanced English language proficiency) was assessed with English literacy skill assessments. Dynamic Indicators of Basic Early Literacy Skills measures were…
Cheung, J.; Veldhuizen, A.G.; Halbertsma, J.P.; Maurits, N.M.; Sluiter, W.J.; Cool, J.C.; van Horn, J.R.
2004-01-01
Study Design. A prospective study in which patients with idiopathic scoliosis were examined longitudinally by radiographic and electromyographic measurements according to a protocol. Objectives. To measure the growth velocity of the spine and the electromyographic ratio of the paraspinal muscles to
Liu, Xiao-Hui; Wang, Wei-Liang; Lu, Shao-Yong; Wang, Yu-Fan; Ren, Zongming
2016-08-01
In Zaozhuang, economic development affects the discharge amount of industrial wastewater, chemical oxygen demand (COD), and ammonia nitrogen (NH3-N). To reveal the trend of water environmental quality related to the economy in Zaozhuang, this paper simulated the relationships between industrial wastewater discharge, COD, NH3-N load, and gross domestic product (GDP) per capita for Zaozhuang (2002-2012) using environmental Kuznets curve (EKC) models. The results showed that the added value of industrial GDP, the per capita GDP, and wastewater emission had average annual growth rates of 16.62, 16.19, and 17.89 %, respectively, from 2002 to 2012, while COD and NH3-N emission in 2012, compared with 2002, showed average annual decreases of 10.70 and 31.12 %, respectively. The export of EKC models revealed that industrial wastewater discharge had a typical inverted-U-shaped relationship with per capita GDP. However, both COD and NH3-N showed the binding curve of the left side of the "U" curve and left side U-shaped curve. The economy in Zaozhuang had been at the "fast-growing" stage, with low environmental pollution according to the industrial pollution level. In recent years, Zaozhuang has abated these heavy-pollution industries emphatically, so pollutants have been greatly reduced. Thus, Zaozhuang industrial wastewater treatment has been quite effective, with water quality improved significantly. The EKC models provided scientific evidence for estimating industrial wastewater discharge, COD, and NH3-N load as well as their changeable trends for Zaozhuang from an economic perspective.
Liao, Yue; Shonkoff, Eleanor T; Barnett, Elizabeth; Wen, C K Fred; Miller, Kimberly A; Eddy, J Mark
2015-10-01
School shootings may have serious negative impacts on children years after the event. Previous research suggests that children exposed to traumatic events experience heightened fear, anxiety, and feelings of vulnerability, but little research has examined potential aggressive and disruptive behavioral reactions. Utilizing a longitudinal dataset in which a local school shooting occurred during the course of data collection, this study sought to investigate whether the trajectory of disruptive behaviors was affected by the shooting. A two-piece growth curve model was used to examine the trajectory of disruptive behaviors during the pre-shooting years (i.e., piece one) and post-shooting years (i.e., piece two). Results indicated that the two-piece growth curve model fit the data better than the one-piece model and that the school shooting precipitated a faster decline in aggressive behaviors. This study demonstrated a novel approach to examining effects of an unexpected traumatic event on behavioral trajectories using an existing longitudinal data set. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Jens Jirschitzka
Full Text Available In four studies we tested a new methodological approach to the investigation of evaluation bias. The usage of piecewise growth curve modeling allowed for investigation into the impact of people's attitudes on their persuasiveness ratings of pro- and con-arguments, measured over the whole range of the arguments' polarity from an extreme con to an extreme pro position. Moreover, this method provided the opportunity to test specific hypotheses about the course of the evaluation bias within certain polarity ranges. We conducted two field studies with users of an existing online information portal (Studies 1a and 2a as participants, and two Internet laboratory studies with mostly student participants (Studies 1b and 2b. In each of these studies we presented pro- and con-arguments, either for the topic of MOOCs (massive open online courses, Studies 1a and 1b or for the topic of M-learning (mobile learning, Studies 2a and 2b. Our results indicate that using piecewise growth curve models is more appropriate than simpler approaches. An important finding of our studies was an asymmetry of the evaluation bias toward pro- or con-arguments: the evaluation bias appeared over the whole polarity range of pro-arguments and increased with more and more extreme polarity. This clear-cut result pattern appeared only on the pro-argument side. For the con-arguments, in contrast, the evaluation bias did not feature such a systematic picture.
Jirschitzka, Jens; Kimmerle, Joachim; Cress, Ulrike
2016-01-01
In four studies we tested a new methodological approach to the investigation of evaluation bias. The usage of piecewise growth curve modeling allowed for investigation into the impact of people's attitudes on their persuasiveness ratings of pro- and con-arguments, measured over the whole range of the arguments' polarity from an extreme con to an extreme pro position. Moreover, this method provided the opportunity to test specific hypotheses about the course of the evaluation bias within certain polarity ranges. We conducted two field studies with users of an existing online information portal (Studies 1a and 2a) as participants, and two Internet laboratory studies with mostly student participants (Studies 1b and 2b). In each of these studies we presented pro- and con-arguments, either for the topic of MOOCs (massive open online courses, Studies 1a and 1b) or for the topic of M-learning (mobile learning, Studies 2a and 2b). Our results indicate that using piecewise growth curve models is more appropriate than simpler approaches. An important finding of our studies was an asymmetry of the evaluation bias toward pro- or con-arguments: the evaluation bias appeared over the whole polarity range of pro-arguments and increased with more and more extreme polarity. This clear-cut result pattern appeared only on the pro-argument side. For the con-arguments, in contrast, the evaluation bias did not feature such a systematic picture.
生长曲线模型中参数估计误差的上界%Upper Bound on the Estimation Error in a Growth Curve Model
Institute of Scientific and Technical Information of China (English)
左卫兵; 时文芳
2015-01-01
研究了生长曲线模型中利用lasso所得到的参数估计B^ L 的误差。在设计矩阵X1分别满足RE条件、兼容性条件和UDP条件时，依次得到估计误差‖^B L -B‖1的上界，并且该上界与协调参数成正比。%The upper bound of the estimation error in a growth curve model was discussed. Based on the lasso in the linear regression, the lasso estimation was obtained in the growth curve model. When the de-sign matrix X1 satisfies RE condition ( restricted eigenvalue condition) , compatibility condition, and UDP ( universal distortion property ) condition, the corresponding upper bound on estimation error‖B^L-B‖1 was successively identified. And the upper bounds were proportion to the tuning parameter.
Meera, M. R.; Dipuna Das, C. N.; Bena Jothy, V.; Rayar, S. L.
2016-10-01
Nonlinear optics is a topic of much current interest that exhibits a great diversity. This is due to the technological potentials of certain nonlinear optical effects for photonic based technologies. Many NLO crystals grown by mixing amino acids with various organic and inorganic acids have been reported in the literature. Hence, glycine mixed semi-organic material will be of special interest as a fundamental building block to develop many complex crystals with improved NLO properties. In this context, the present work it is attempted to grow NLO active Triglycine phosphate [(NH2CH2COOH)3H3PO4](TGP) crystal from aqueous solution at room temperature by slow evaporation method. The geometry, intermolecular hydrogen bonding and harmonic vibrational wavenumbers of TGP was investigated with the help of B3LYP density functional theory (DFT) methods. Natural Bond Orbital (NBO) analysis confirms the occurrence of strong intermolecular N-H...O hydrogen bond. Second harmonic frequency generation was examined by Kurtz and Perry powder test. Theoretical first order hyperpolarizability value was calculated.
Synthesis, growth and characterization of a nonlinear optical crystal: l-Leucinium perchlorate
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P. Baskaran
2017-01-01
Full Text Available An amino acid based semiorganic nonlinear optical family single crystal of l-leucinium perchlorate (LLPCl was grown by the solvent evaporation method at ambient temperature. Good optical quality single crystals up to a size of 6 mm × 5 mm × 3 mm were obtained. The single-crystal XRD analysis shows that the grown crystals have a monoclinic structure. Fourier transform infrared (FTIR spectral analysis and UV–vis spectral studies were also carried out. Microhardness mechanical studies show that the hardness number (Hv of a LLPCl single crystal decreases with the load as measured by the Vickers microhardness method. The dielectric properties of the grown crystal were analysed by varying the frequency. Photoconductivity analysis gives the variation of the photocurrent and dark current. The nonlinear optical properties were studied using the Kurtz and Perry powder method and the second harmonic generation efficiency was found to be 2.6 times higher than that of KDP crystals.
Growth and characterization of L-alanine cadmium bromide a semiorganic nonlinear optical crystals
Ilayabarathi, P.; Chandrasekaran, J.
2012-10-01
A new semiorganic nonlinear optical crystal, L-alanine cadmium bromide (LACB) was grown from aqueous solution by slow solvent evaporation method at room temperature. As grown crystals were characterized for its spectral, thermal, linear and second order nonlinear optical properties. LACB crystallizes in orthorhombic system and unit cell parameters a = 5.771(2) Å, b = 6.014(4) Å, c = 12.298(2) Å, α = β = γ = 90° and volume = 426.8(3) Å3. The mode of vibrations of different molecular groups present in the crystal was identified by FTIR study. The grown crystals were found to be transparent in the entire visible region. The thermal strength and the decomposition of the grown crystals were studied using TG/DTA and DSC analysis. Dielectric measurement revealed that the crystals had very low dielectric constant at higher frequency in room temperature. The mechanical behavior was studied by Vicker's microhardness tester. The grown crystal has negative photoconductivity nature. The fluorescence spectrum of the crystal was recorded and its optical band gap is about 3.356 eV. The NLO property of crystal using modified Kurtz-Perry powder technique with Nd:YAG laser light of wavelength 1064 nm indicated that their second harmonic generation (SHG) efficiency was half that of pure KDP.
Directory of Open Access Journals (Sweden)
Eva Maria Griebeler
Full Text Available Information on aging, maturation, and growth is important for understanding life histories of organisms. In extinct dinosaurs, such information can be derived from the histological growth record preserved in the mid-shaft cortex of long bones. Here, we construct growth models to estimate ages at death, ages at sexual maturity, ages at which individuals were fully-grown, and maximum growth rates from the growth record preserved in long bones of six sauropod dinosaur individuals (one indeterminate mamenchisaurid, two Apatosaurus sp., two indeterminate diplodocids, and one Camarasaurus sp. and one basal sauropodomorph dinosaur individual (Plateosaurus engelhardti. Using these estimates, we establish allometries between body mass and each of these traits and compare these to extant taxa. Growth models considered for each dinosaur individual were the von Bertalanffy model, the Gompertz model, and the logistic model (LGM, all of which have inherently fixed inflection points, and the Chapman-Richards model in which the point is not fixed. We use the arithmetic mean of the age at the inflection point and of the age at which 90% of asymptotic mass is reached to assess respectively the age at sexual maturity or the age at onset of reproduction, because unambiguous indicators of maturity in Sauropodomorpha are lacking. According to an AIC-based model selection process, the LGM was the best model for our sauropodomorph sample. Allometries established are consistent with literature data on other Sauropodomorpha. All Sauropodomorpha reached full size within a time span similar to scaled-up modern mammalian megaherbivores and had similar maximum growth rates to scaled-up modern megaherbivores and ratites, but growth rates of Sauropodomorpha were lower than of an average mammal. Sauropodomorph ages at death probably were lower than that of average scaled-up ratites and megaherbivores. Sauropodomorpha were older at maturation than scaled-up ratites and average
Gao, C Q; Yang, J X; Chen, M X; Yan, H C; Wang, X Q
2016-04-01
Two experiments were conducted to fit growth curves, and determine age-related changes in carcass characteristics, organs, serum biochemical parameters, and gene expression of intestinal nutrient transporters in domestic pigeon (Columba livia). In experiment 1, body weight (BW) of 30 pigeons was respectively determined at 1, 3, 7, 14, 21, 28, and 35 days old to fit growth curves and to describe the growth of pigeons. In experiment 2, eighty-four 1-day-old squabs were grouped by weight into 7 groups. On d 1, 3, 7, 14, 21, 28, and 35, twelve birds from each group were randomly selected for slaughter and post-slaughter analysis. The results showed that BW of pigeons increased rapidly from d 1 to d 28 (a 25.7-fold increase), and then had little change until d 35. The Logistic, Gompertz, and Von Bertalanffy functions can all be well fitted with the growth curve of domestic pigeons (R2>0.90) and the Gompertz model showed the highest R2value among the models (R2=0.9997). The equation of Gompertz model was Y=507.72×e-(3.76exp(-0.17t))(Y=BW of pigeon (g); t=time (day)). In addition, breast meat yield (%) increased with age throughout the experiment, whereas the leg meat yield (%) reached to the peak on d 14. Serum total protein, albumin, globulin, and glucose concentration were increased with age, whereas serum uric acid concentration was decreased (P<0.05). Furthermore, the gene expressions of nutrient transporters (y+LAT2, LAT1, B0AT1, PepT1, and NHE2) in jejunum of pigeon were increased with age. The results of correlation analysis showed the gene expressions of B0AT1, PepT1, and NHE2 had positive correlations with BW (0.73
van de Poll, M L; van Rotterdam, W; Gadellaa, M M; Stortelers, C; van Vugt, M J; van Zoelen, E J
2000-07-01
With the help of 16 chimaeras between human epidermal growth factor (hEGF) and human transforming growth factor alpha (hTGF alpha), a detailed analysis was performed on the epitope recognized by two polyclonal antibodies raised against hEGF, and one polyclonal antibody raised against hTGF alpha. All three antibodies recognized essentially the same antigenic site, a non-linear and conformation-dependent sequence that is located near the second and fourth disulphide-bonded cysteines and that includes the start of the B-loop beta-sheet. The epitope recognized by the anti-hEGF antibodies was further characterized using 8 chimaeras between hEGF and an EGF-repeat from Drosophila Notch and was found to include Met(21), Ala(30) and Asn(32). All three polyclonal antibodies were able to neutralize the biological activity of the respective growth factor when tested on 32D murine haematopoietic progenitor cells transfected with ErbB-1, indicating that the receptor binding domain is shielded upon binding of the antibody.
Directory of Open Access Journals (Sweden)
M. Packiya raj
2017-01-01
Full Text Available A new inorganic nonlinear optical single crystal of sodium manganese tetrachloride (SMTC has been successfully grown from aqueous solution using the slow evaporation technique at room temperature. The crystals obtained using the aforementioned method were characterized using different techniques. The crystalline nature of the as-grown crystal of SMTC was analyzed using powder X-ray diffraction. Single-crystal X-ray diffraction revealed that the crystal belongs to an orthorhombic system with non-centrosymmetric space group Pbam. The optical transmission study of the SMTC crystal revealed high transmittance in the entire UV–vis region, and the lower cut-off wavelength was determined to be 240 nm. The mechanical strength of the as-grown crystal was estimated using the Vickers microhardness test. The second harmonic generation (SHG efficiency of the crystal was measured using Kurtz's powder technique, which indicated that the crystal has a nonlinear optical (NLO efficiency that is 1.32 times greater than that of KDP. The dielectric constant and dielectric loss of the compound were measured at different temperatures with varying frequencies. The photoconductivity study confirmed that the title compound possesses a negative photoconducting nature. The growth mechanism and surface features of the as-grown crystals were investigated using chemical etching analysis.
Kalaivanan, R.; Srinivasan, K.
2017-05-01
Synthesis of the organic nonlinear optical compound N-benzyl-2-methyl-4-nitroaniline (BNA) was carried out in a newer chemical environment using the mixture of benzyl chloride and 2-methl-4-nitroaniline by a preferred laboratory synthesis process. The synthesized BNA compound was separated by column chromatography (CC) with low pressure silica gell using petrollium benzine and purity of the separated resultant product was confirmed by thin layer chromatography (TLC). Further, the material was recrystallized atleast four times in methanol and the highly purified BNA was used for the growth of single crystals from solutions with selected solvents by slow evaporation method at room temperature. Single crystals having natural growth morphology were harvested and their different growth faces were identified by optical goniometry. The grown crystals were subjected to different characterization techniques such as powder x-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and UV-vis-Near IR spectroscopy. Further, the second harmonic generation (SHG) efficiency of the grown BNA crystal was studied by Kurtz and Perry powder technique using Nd:YAG laser as fundamental source and found to be twice that of inorganic standard KDP.
Leslie, Thomas M.
1995-01-01
Data obtained from the electric field induced second harmonic generation (EFISH) and Kurtz Powder Methods will be provided to MSFC for further refinement of their method. A theoretical model for predicting the second-order nonlinearities of organic salts is being worked on. Another task is the synthesis of a number of salts with various counterions. Several salts with promising SHG activities and new salts will be tested for the presence of two crystalline forms. The materials will be recrystallized from dry and wet solvents and compared for SHG efficiency. Salts that have a high SHG efficiency and no tendency to form hydrates will be documented. The synthesis of these materials are included in this report. A third task involves method to aid in the growth of large, high quality single crystals by solution processes. These crystals will be characterized for their applicability in the fabrication of devices that will be incorporated into optical computers in future programs. Single crystals of optimum quality may be obtained by crystal growth in low-gravity. The final task is the design of a temperature lowering single crystal growth apparatus for ground based work. At least one prototype will be built.
Institute of Scientific and Technical Information of China (English)
李丽霞; 张岩波; 郜艳晖; 张敏; 周舒冬
2013-01-01
To explore the improvement of clinical symptoms after treatment on patients with depression under the latent growth curve modeling.514 patients were studied with Hamilton Depression Rating Scale for depression and nonlinear conditional.Latent growth curve modeling was constructed to assess the features of outcome growth trajectory and possible related influencing factors.Results indicated that the outcome measure showing nonlinear growth trajectory and rapid drop during the first follow-up period and then declining or leveling off for the rest of the observation period on symptoms of anxiety,cognitive disturbance,retardation,sleeping disorder and HAMD scores.The variances of both latent intercept and the slope growth factor were statistically significant,indicating they varied across individuals.Gender did not show significant effect on both the intercept and the slope growth factor for the six outcomes,while age had a significant positive effect on initial weight loss,sleep disorder and HAMD scores at the baseline (0.015,0.048 and 0.068,P＜0.05) survey.Marriage showed significant positive effect on intercept factor of anxiety symptoms (0.563,P＜0.05) but negative effect on slope growth factor (-0.244,P＜0.05) while family history had significant positive effect on intercept factor regarding retardation (0.471,P＜0.05).The level of received education had a significant negative effect on intercept factor of anxiety symptoms and HAMD scores (-0.424 and-0.914,P＜0.05).Latent growth curve models allowed the researchers to study the overall growth trajectory as well as the captured individual differences on these trajectories over time,that also provided a powerful tool for the analysis on longitudinal data.%运用潜变量增长曲线模型探讨抑郁症患者治疗后临床症状的改善情况.对汉密顿抑郁量表的体重减轻等因子构建非线性条件增长曲线模型,探讨其轨迹的发展变化情况及可能影响因素.结果表明焦虑、
Energy Technology Data Exchange (ETDEWEB)
Balasubramanian, D. [Post Graduate and Research Department of Physics, Pachaiyappa' s College, Chennai 600030 (India); Sankar, R. [Crystal Growth Centre, Anna University, Chennai 600025 (India); Shankar, V. Siva [Post Graduate and Research Department of Physics, Pachaiyappa' s College, Chennai 600030 (India); Murugakoothan, P. [Post Graduate and Research Department of Physics, Pachaiyappa' s College, Chennai 600030 (India)], E-mail: pmurugakoothan@yahoo.com; Arulmozhichelvan, P. [Post Graduate and Research Department of Physics, Pachaiyappa' s College, Chennai 600030 (India); Jayavel, R. [Crystal Growth Centre, Anna University, Chennai 600025 (India)
2008-01-15
A new semiorganic nonlinear optical rubidium bis-DL-malato borate (RBMB) has been synthesized and single crystals were grown by slow cooling technique from aqueous solution. The grown crystals have been characterized by X-ray diffraction (single crystal XRD) to confirm the formation of the crystalline phases. FT-IR and FT-Raman spectroscopic analyses confirm the presence of all the functional groups in the grown crystals. TG-DTA studies reveal that the material is stable up to 230 deg. C. The UV-vis transmission spectrum shows a lower cutoff wavelength of 230 nm. The emission of SHG using Nd:YAG laser is confirmed by a modified Kurtz and Perry powder setup.
Growth and characterization of an organic nonlinear optical material: L-Histidine malonate
Ramya, K.; Saraswathi, N. T.; Raja, C. Ramachandra
2016-10-01
L-Histidine malonate is one of the potential organic material for nonlinear optical applications. Single crystals of L-Histidine malonate were grown by the liquid diffusion method. The lattice parameter values were evaluated from single crystal X-ray diffraction technique. The Fourier Transform Infra Red and Raman spectral studies were employed to identify the different modes of vibrations of molecular groups in the crystal. Optical characterization and the percentage of optical transmission were recorded using UV-vis-NIR spectroscopy. The molecular structure was established by proton and carbon Nuclear magnetic resonance spectral studies. The thermal behavior of the material has been studied by Thermo gravimetric and Differential thermal plots. The second harmonic generation conversion efficiency was found out from the powder technique of Kurtz and Perry.
Saravanan, M.; Senthil, A.; Rajasekar, S. Abraham
2016-09-01
Good optical quality, potential second order nonlinear optical crystal L-asparaginium picrate (LASP) was grown by the slow cooling method. The solubility and metastable zone width of LASP specimen was studied. The LASP crystal belongs to monoclinic crystal system with noncentrosymmetric space group P21. UV-Visible-NIR transmittance spectrum determines the optical band gap of LASP. Excellence of the grown crystal is ascertained by the etching studies. Laser Damage Threshold and Photoluminescence studies designate that the grown crystal contains less imperfection. The mechanical behaviour of LASP sample was investigated at different temperatures. The piezoelectric nature, Photoconductive nature and the relative Second Harmonic Generation (for various particle sizes) of the material were also studied. Birefringence and ocular (optical) homogeneity of the crystal were assessed using modified channel spectrum method.
Growth and characterization of an organic nonlinear optical crystal: Glycinium trichloroacetate
Energy Technology Data Exchange (ETDEWEB)
Peter, M. Esthaku [Department of Physics, Easwari Engineering College, Chennai 600089 (India); Ramasamy, P., E-mail: proframasamy@hotmail.com [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603110 (India)
2012-11-15
Single crystal of glycinium trichloroacetate, an organic nonlinear optic (NLO) material, has been grown by slow solvent evaporation technique at room temperature. The grown crystal was subjected to single crystal X-ray diffraction for confirming the coordination formed, and the presence of various functional groups was studied by FTIR in the range 4000-450 cm{sup -1}. UV-Visible transmittance studies were performed to analyze optical transparency of the crystal and second harmonic generation was investigated to explore the NLO property of the material. Thermogravimetric and differential thermal analysis have been performed to study thermal properties of the grown crystal. Dielectric constant and dielectric loss were studied at different temperatures and frequencies. Vicker's microhardness testing was carried out on the as grown crystal to reveal the mechanical properties of the crystal. Etching studies were made on the as grown crystal to analyze the structural imperfection of the crystal.
A nonlinear competitive model of the prostate tumor growth under intermittent androgen suppression.
Yang, Jing; Zhao, Tong-Jun; Yuan, Chang-Qing; Xie, Jing-Hui; Hao, Fang-Fang
2016-09-01
Hormone suppression has been the primary modality of treatment for prostate cancer. However long-term androgen deprivation may induce androgen-independent (AI) recurrence. Intermittent androgen suppression (IAS) is a potential way to delay or avoid the AI relapse. Mathematical models of tumor growth and treatment are simple while they are capable of capturing the essence of complicated interactions. Game theory models have analyzed that tumor cells can enhance their fitness by adopting genetically determined survival strategies. In this paper, we consider the survival strategies as the competitive advantage of tumor cells and propose a new model to mimic the prostate tumor growth in IAS therapy. Then we investigate the competition effect in tumor development by numerical simulations. The results indicate that successfully IAS-controlled states can be achieved even though the net growth rate of AI cells is positive for any androgen level. There is crucial difference between the previous models and the new one in the phase diagram of successful and unsuccessful tumor control by IAS administration, which means that the suggestions from the models for medication can be different. Furthermore we introduce quadratic logistic terms to the competition model to simulate the tumor growth in the environment with a finite carrying capacity considering the nutrients or inhibitors. The simulations show that the tumor growth can reach an equilibrium state or an oscillatory state with the net growth rate of AI cells being androgen independent. Our results suggest that the competition and the restraint of a limited environment can enhance the possibility of relapse prevention.
Directory of Open Access Journals (Sweden)
Justina Inês Anselmini
2008-08-01
Full Text Available The objectives of this work were to describe the development and growth rate of the pine cones of Araucaria angustifolia during and after the pollination period, to identify the period of maximum growth of the cones and the period of pollination and maturation of the pine nuts. The adult individuals were found at the Setor de Ciencias Agrarias of the UFPR, in Curitiba - PR. Collections and measurements of pine cones were made in 2003 and 2005. The diameter and the length of the pine cones were measured 15 different times in both the years. In the studied environmental conditions, the period between the pollination and maturation of the pine nuts was 20 months. The maximum pine cone growth was achieved between October and January after the pollination, and between October and April of the following year.O objetivo deste trabalho foi descrever o desenvolvimento e o crescimento das pinhas da Araucaria angustifolia durante e após o período de polinização, identificando os períodos de maior crescimento das pinhas, a época de polinização e maturação dos pinhões. As plantas adultas pesquisadas situam-se no Setor de Ciências Agrárias da UFPR, em Curitiba - PR. Para o acompanhamento do crescimento das pinhas foram realizadas coletas e medições de pinhas durante os anos de 2003 a 2005. O diâmetro e o comprimento das pinhas foram medidos em 15 datas, durante os três anos. Para as condições ambientais de Curitiba, o período compreendido entre a polinização das pinhas e a maturação das sementes foi de 20 meses. Há dois picos de crescimento das pinhas, um de outubro a janeiro, logo após a polinização, e outro de outubro a abril do ano seguinte.
Senthil, A.; Loganayaki, M.; Lenin, M.; Ramasamy, P.
2012-06-01
A semi-organic nonlinear optical material, sodium di(L-malato) borate (NaDMB) has been synthesized. Optically good quality bulk single crystal of NaDMB was successfully grown by slow evaporation solution technique (SEST) and Sankaranarayanan-Ramasamy (SR) method at 36 °C. Transparent, colourless crystal of size 22 mm X 8 mm X 6 mm with well defined morphology was grown by SEST and oriented unidirectional bulk single crystal of size 48 mm length and 16 mm diameter was grown by SR method. The grown crystals were subjected to single crystal X-ray diffraction studies. The crystal belongs to monoclinic structure with space group P21. The grown crystals were characterized by UV-vis studies. The structural perfection of the grown crystal has been analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. The differential thermal (DTA) and thermogravimetric (TG) analysis traces reveal the thermal stability of the sample. The second-harmonic generation efficiency was estimated by Kurtz and Perry powder technique.
不同性别黑番鸭生长曲线的拟合和分析%Analysis and Fitting of Growth Curve in Different Sexual Black Muscovy
Institute of Scientific and Technical Information of China (English)
朱志明; 黄种彬; 钟志新; 缪中纬; 陈晖; 郑嫩珠
2011-01-01
As the black Muscovy for experimental material, the early bodyweight of different sexual black Muscovy from 0 to 10 weeks old were measured, in order to investigate the growth model in this study, three kinds of nonlinear models of Gompertz, Logistic and von Bertalanffy were used to fit the growth curve respectively. The results showed that black Muscovy grew slowly before age of 4 weeks, the growth rate accelerated significantly after age of 4 weeks, and reached the growth peak at age of 6 to 10 weeks. Compared with goodness of fit (R2), the results showed the growth curve could be well fitted with these three models and the R2 was above 0. 99, but the Gompertz model had well closed to the actual observed values . Further more, the fitting parameters of Gompertz model between genders were compared, and the male black Muscovy showed higher initial weight, maximum bodyweight, and inflection point weight than female black Muscovy. The inflection age of male was 5. 3 weeks and the female was 4. 3 weeks. The Gomperte model equation for male and female black muscovy was W=3111. 4 [exp - 4. 4482exp (- 0. 2802t)] and W=2100. 4 [exp-4. 1071exp ( - 0. 32250] respectively. This study would help to understand the growth model and development of different sexual black Muscovy, and would provide the scientific basis for rational use of resources, breeding germplasm and selection in black Muscovy.%以黑番鸭为试验材料,测定了不同性别黑番鸭从初生到10周龄的体重,用Gompertz、Logistic、von Bertalanffy 3种非线性生长模型拟合其生长曲线,研究不同性别黑番鸭生长模式的差异.结果表明:公、母黑番鸭在4周龄前生长较为缓慢,4周龄后生长速度开始明显加快,在6～10周龄达到生长高峰.通过比较拟合度(R2)发现3种曲线模型拟合度均达到0.99以上,但Gompertz模型的拟合结果更接近于实际测量值,拟合效果最佳.进一步比较不同性别黑番鸭Gompertz模型拟合参数,结果发
酉州乌羊生长曲线拟合分析研究%Study on growth curve fitting of YouZhou Black Goat
Institute of Scientific and Technical Information of China (English)
方亚; 黄勇富; 王高富
2011-01-01
对酉州乌羊体重随月龄增长应用Logistic、Gompertz、Richards模型进行生长曲线拟合分析,建立公、母羊的拟合曲线方程及求出拐点体重、拐点月龄。结果表明：三种模型均能很好地拟合公、母羊生长规律,Logistic、Gompertz、Richards模型拟合公羊的拟合度（R2）分别为0.987、0.995、0.987,母羊拟合度（R2）0.968、0.9810.968,三种模型相互比较,Gompertz模型拟合效果最好。%Youzhou black goats weight increase with age application Logistic, Gompertz, Richardss model for growth curve fitting analysis, male goat and famale goat＇s equation and find the Inflexion point of body weight, Inflexion age. maximal growth rate.The results showed that：three models can fit male goat and famale goat growth pattern, Logistic, Gompertz, Richards three model fitting male goat goodness of fit （R2） were 0.987,0.995,0.987,famale goat goodness of fit （R2） 0.968,0.981 0.968, three models compare with each other, Gompertz model fit the best.
Malenovská, Hana
2016-02-01
Only very few comparative studies have been performed that evaluate general trends of virus growth under 3D in comparison with 2D cell culture conditions. The aim of this study was to investigate differences when four animal viruses are cultured in 2D and 3D. Suid herpesvirus 1 (SuHV-1), Vesicular stomatitis virus (VSIV), Bovine adenovirus (BAdV) and Bovine parainfluenza 3 virus (BPIV-3) were cultivated in 3D rotating wall vessels (RWVs) and conventional 2D cultures. The production of virus particles, the portion of infectious particles, and the infectious growth curves were compared. For all viruses, the production of virus particles (related to cell density), including the non-infectious ones, was lower in 3D than in 2D culture. The production of only infectious particles was significantly lower in BAdV and BPIV-3 in 3D cultures in relation to cell density. The two cultivation approaches resulted in significantly different virus particle-to-TCID50 ratios in three of the four viruses: lower in SuHV-1 and BPIV-3 and higher in BAdV in 3D culture. The infectious virus growth rates were not significantly different in all viruses. Although 3D RWV culture resulted in lower production of virus particles compared to 2D systems, the portion of infectious particles was higher for some viruses.
DEFF Research Database (Denmark)
Brünner, N; Spang-Thomsen, M; Vindeløv, L
1985-01-01
of the treatment was evaluated using growth curves and flow cytometric DNA analysis. The treatment induced a dose-dependent growth delay and dose-dependent changes in the cell cycle distribution. The cell cycle changes comprised a decrease in the G1 phase, an accumulation of cells in the S phase, and an increasing...
Energy Technology Data Exchange (ETDEWEB)
Garces, F.; Vidania, R. de
1984-07-01
In this work an integral parametrization of the bacterial growth curve is presented. The values of the parameters are obtained by fitting to the experimental data. Those parameters, with allow to describe the growth in its different phases, are the followings: slopes of the curve in its three parts and the time which divides the last two phases of the bacterial growth. The experimental data are bacterial densities measured by optical methods. The bacteria used was the E. coli C{sub 6}00. (Author)
Energy Technology Data Exchange (ETDEWEB)
Borglin, Sharon E; Joyner, Dominique; Jacobsen, Janet; Mukhopadhyay, Aindrila; Hazen, Terry C.
2008-10-04
Growing anaerobic microorganisms in phenotypic microarrays (PM) and 96-well microtiter plates is an emerging technology that allows high throughput survey of the growth and physiology and/or phenotype of cultivable microorganisms. For non-model bacteria, a method for phenotypic analysis is invaluable, not only to serve as a starting point for further evaluation, but also to provide a broad understanding of the physiology of an uncharacterized wild-type organism or the physiology/phenotype of a newly created mutant of that organism. Given recent advances in genetic characterization and targeted mutations to elucidate genetic networks and metabolic pathways, high-throughput methods for determining phenotypic differences are essential. Here we outline challenges presented in studying the physiology and phenotype of a sulfate reducing anaerobic delta proteobacterium, Desulfovibrio vulgaris Hildenborough. Modifications of the commercially available OmniLog(TM) system (Hayward, CA) for experimental setup, and configuration, as well as considerations in PM data analysis are presented. Also highlighted here is data viewing software that enables users to view and compare multiple PM data sets. The PM method promises to be a valuable strategy in our systems biology approach to D. vulgaris studies and is readily applicable to other anaerobic and aerobic bacteria.
Growth and properties of semi-organic nonlinear optical crystal: L-Glutamic acid hydrochloride
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J. Uma
2016-02-01
Full Text Available Semiorganic nonlinear optical crystal of L-Glutamic acid hydrochloride (LGHC was grown from aqueous solution by slow evaporation technique. Single crystal X-ray Diffraction analysis confirms that LGHC crystallizes in orthorhombic system with noncentrosymmetric space group P212121. The powder X-ray diffraction study confirms the crystallinity of the grown crystal. The fundamental functional groups of the grown crystals were analyzed by Fourier Transform Infrared spectroscopic analysis in the range of 450–4000 cm−1. The range of optical transmission was ascertained using UV–vis–NIR studies. The Refractive Index of the LGHC crystal was found to be 1.4. The second harmonic generation efficiency of the LGHC was determined using Kurtz and Perry powder technique and it was 0.5 times greater than that of the KDP crystal. Thermo Gravimetric Analysis (TGA and Differential Thermal Analysis (DTA were used to study thermal behavior of the sample. The dielectric behavior and ac conductivity of the sample were studied as a function of frequency for different temperatures. The mechanical strength of the crystal was determined by Vicker׳s Hardness test. The elastic stiffness constant and yield strength of the sample was calculated.
Prabhu, Shobha R.; Jayarama, A.; Chandrasekharan, K.; Upadhyaya, V.; Ng, Seik Weng
2017-05-01
A new chalcone compound (2E)-3-(3-methylphenyl)-1-(4-nitrophenyl)prop-2-en-1-one (3MPNP) with molecular formula C16H13NO3 has been synthesized and crystallized by slow solvent evaporation technique. The Fourier transform infrared, Fourier transform Raman and nuclear magnetic resonance techniques were used for structural characterization. UV-visible absorption studies were carried out to study the transparency of the crystal in the visible region. Differential scanning calorimetry study shows thermal stability of crystals up to temperature 122 °C. Single crystal X-ray diffraction and powder X-ray diffraction techniques were used to study crystal structure and cell parameters. The Hirshfeld surface and 2-D fingerprint analysis were performed to study the nature of interactions and their quantitative contributions towards the crystal packing. The third order non-linear optical properties have been studied using single beam Z-scan technique and the results show that the material is a potential candidate for optical device applications such as optical limiters and optical switches.
Growth and properties of semi-organic nonlinear optical crystal：L-Glutamic acid hydrochloride
Institute of Scientific and Technical Information of China (English)
J.Uma; V.Rajendran
2016-01-01
Semiorganic nonlinear optical crystal of L-Glutamic acid hydrochloride (LGHC) was grown from aqueous solution by slow evaporation technique. Single crystal X-ray Diffraction analysis confirms that LGHC crystallizes in orthorhombic system with noncentrosymmetric space group P212121. The powder X-ray diffraction study confirms the crystallinity of the grown crystal. The fundamental functional groups of the grown crystals were analyzed by Fourier Transform Infrared spectroscopic analysis in the range of 450–4000 cm¯1. The range of optical transmission was ascertained using UV–vis–NIR studies. The Refractive Index of the LGHC crystal was found to be 1.4. The second harmonic generation efficiency of the LGHC was determined using Kurtz and Perry powder technique and it was 0.5 times greater than that of the KDP crystal. Thermo Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) were used to study thermal behavior of the sample. The dielectric behavior and ac conductivity of the sample were studied as a function of frequency for different temperatures. The mechanical strength of the crystal was determined by Vicker's Hardness test. The elastic stiffness constant and yield strength of the sample was calculated.
Vela, T.; Selvarajan, P.; Freeda, T. H.; Balasubramanian, K.
2013-04-01
Lithium sulphate admixtured l-alanine (LSLA) salt was synthesized and the solubility of the commercially available l-alanine and the synthesized LSLA sample was determined in de-ionized water at various temperatures. In accordance with the solubility data, the saturated aqueous solutions of l-alanine and lithium admixtured l-alanine were prepared separately and the single crystals of the samples were grown by the solution method with a slow evaporation technique. Studying single x-ray diffraction shows that pure and LSLA crystal belong to the orthorhombic system with a non-centrosymmetric space group P212121. Using the powder x-ray diffraction study, the crystallinity of the grown crystals is confirmed and the diffraction peaks are indexed. The various functional groups present in the pure and LSLA crystal are elucidated from Fourier transform infrared spectroscopy study. UV-visible transmittance is recorded to study the optical transmittance range for the grown crystals. The powder second harmonic generation test confirms the nonlinear optical property of the grown crystals. From the microhardness test, the hardness of the grown crystals is estimated. The dielectric behaviour, such as the dielectric constant and the loss of the sample, are measured as a function of temperature and frequency. The ac conductivity of the grown crystals is also studied and the activation energy is calculated.
Crystal growth and characterisation of mixed niobates for non-linear optical applications
Jiang, Q
1999-01-01
Temperature tuned NCPM has been realised by using both wavelengths. The measured phase matching temperatures increase with increasing spontaneous polarisation. KLN also has large non-linear optical coefficient (d sub 3 sub 1 =2.14 d sub 3 sub 1 sup l sup i sup N sup b sup O sup 3), a reasonably high damage threshold (1.75 times that of LiNbO sub 3), wide temperature acceptance (approx 5 deg C) and angular acceptance (approx 8 deg). Potassium sodium niobate (K sub x Na sub 1 sub - sub x NbO sub 3 , KNN) crystals have been grown and they are confirmed to be ferroelectric. However, they are unstable and break up into small pieces after a short period of time. By employing ferroelectric phenomenological theory, it is revealed that the birefringence of a ferroelectric crystal consists of two parts: one relating to a ferroelectric free of any electrical displacement and the other depending on the spontaneous polarisation. The theoretical outcomes provide a brief explanation of the experimental results in modifying ...
Thayanithi, V.; Rajesh, K.; Praveen Kumar, P.
2017-08-01
An aminoacid nonlinear optical crystal of L-alaninium p-toluenesulfonate (LAPT) was grown by Sankaranarayanan and Ramasamy (SR) method. The seed crystal of LAPT was grown with the help of a conventional solution method. The size of the grown crystal is 50 mm length and 20 mm diameter for (0 1 0) plane. The solubility of LAPT was determined in deionized water. The grown LAPT crystal belongs to the orthorhombic crystal system with noncentrosymmetric space group P212121. The morphology of the grown LAPT crystal reveals a hexagonal shape with six facet. The lower cut-off wavelength of the grown crystal is found to be 285 nm. Optical transmittance of the crystal grown by SR method is increased by 20%, when compared with the conventionally grown crystal. The LDT value of the SR-grown LAPT crystal has increased by 0.57 GW cm-2, compared with LAPT crystal grown by conventional method. The emission spectra of the grown crystal was analysed by photoluminescence analysis. The mechanical strength of the grown LAPT crystal was analysed by using Vickers hardness test, and the work hardening coefficient (n) of the LAPT crystal grown by SR method is found to be 2.20. The second harmonic generation efficiency of the LAPT crystal is 2.1 times that of KDP.
Growth and nonlinearity. Final project report, April 1, 1985--January 1, 1996
Energy Technology Data Exchange (ETDEWEB)
Sander, L.M.; Savit, R.
1998-05-01
This research had three major themes: Fractal growth, pattern formation and the analysis of complexity; that is, the effects of random processes in creating hidden order in statistical system, the interplay between this hidden order and macroscopic order, and the analysis of these complex systems. For example, a dendritic crystal such as a snowflake has a complicated and beautiful pattern with much evidence of the underlying six-fold symmetry of ice. It is a pattern forming system. However, in a disordered environment (such as growth on a rough or dirty surface) this order is replaced by a new order, the fractal or scaling symmetry of a disordered crystal. In this case every part of the crystal is similar on the average to the whole (up to a change in scale). The description of these new kinds of order may require the introduction of new analytic and numerical methods.
Srinivasan, Bikshandarkoil R
2015-01-05
The title paper (Manimekalai et al., 2014) reports a slow evaporation solution growth of a so called 'Aloevera amino acid added lithium sulfate monohydrate' (AALSMH) crystal. In this communication, many points of criticism, concerning the crystal growth, NMR spectrum and X-ray powder pattern of this so called AALSMH nonlinear optical crystal are highlighted. Copyright © 2014 Elsevier B.V. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Helen, F.; Kanchana, G., E-mail: kanchanagac@gmail.com
2015-02-01
Nonlinear optical single crystals of L-histidinium dipicrate dihydrate (LHDPDH) were grown by slow evaporation solution growth technique at room temperature. The microstructure and growth features were analysed by chemical etching. The grown crystal was subjected to X-ray diffraction analysis to confirm its purity and crystal structure. Mechanical behaviour of the grown crystal was analysed by Vicker's microhardness test. The stiffness constant was evaluated for various loads. The dielectric behaviour was investigated at different frequencies and temperatures. AC conductivity and activation energy were determined. Electronic properties, such as valence electron plasma energy, average energy gap or Penn gap, Fermi energy and electronic polarizability were calculated. Thermal analysis confirmed the association of two water molecules in the crystal lattice of LHDPDH and revealed the thermal stability of the crystal. Photoconductivity study reveals that LHDPDH exhibits positive photoconductivity. The optical transmission window and optical band gap of the crystal were found by UV–vis–NIR studies. Second harmonic generation efficiency was found to be 2.5 times that of the standard KDP crystal. The laser damage threshold for the grown crystal was measured using Nd:YAG laser. - Highlights: • High stiffness constant indicates strong binding forces between ions. • Low dielectric constant and dielectric loss at high frequencies. • LHDPDH crystal shows positive photoconductivity. • The laser damage threshold is found to be higher than urea. • SHG efficiency is 2.5 times that of KDP.
Directory of Open Access Journals (Sweden)
Tarcisio de Moraes Gonçalves
2011-06-01
Full Text Available Seleção para características do crescimento pode ser feita após ajustadas funções de crescimento para todos os animais sob seleção. Porém, a curva de crescimento de fêmeas é influenciada pelas gestações e lactações subsequentes. Neste trabalho, métodos são descritos para selecionar uma função que ajuste a curva de crescimento de fêmeas bovinas considerando-se os efeitos de variação de peso corporal devido a gestação e a lactação. Foram utilizados dados provenientes do Instituto Agronômico do Paraná, constituindo-se de 15.271 observações de pesos de 103 fêmeas, sendo 43 Nelore, 10 F1 Guzerá x Nelore, 29 F1 Red Angus x Nelore, 5 F1 Marchigiana x Nelore e 16 F1 Simental x Nelore. Comparou-se o ajuste das funções de Brody, Gompertz, Logística, Von Bertalanffy e Michaelis-Menten reparametrizada (MMr aos efeitos do ganho de peso em função da idade, sendo adicionado a todas as funções o ganho de peso durante a gestação e a perda de peso na lactação de fêmeas da raça Nelore e Cruzadas. Ao ajustar as funções, observou-se um Coeficiente de Determinação Múltiplo Ajustado variando entre 0,7552 e 0,9267. Observou-se o menor Quadrado Médio do Resíduo e o Desvio Médio Absoluto para a função de MMr. Para descrição da curva de crescimento em função da idade das fêmeas, deve ser ajustada a função de MMr.Selection for growth characteristics can be done after fitting growth functions for all breeding animals. However, in the female population the growth curve is influenced by gestation and subsequent lactations. In this work methods are described to select a function that fits a growth curve of bovine females considering the varying effects of body weight due to gestation and lactation. Data from the Paraná Agronomic Institute (IAPAR were used consisting of 15.271 weight observations of 103 females distributed as 43 Nelore, 10 F1 Guzerá x Nelore, 29 F1 Red Angus x Nelore, 5 F1 Marchigiana x Nelore and
Nonlinear Relationship of Near-Bed Velocity and Growth of Riverbed Periphyton
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Mohamed Ateia
2016-10-01
Full Text Available Artificial streams were set up to test the relationship between near-bed water velocity and periphyton growth. Periphyton community samples collected from a Japanese stream were incubated for 44 days under a light intensity of 252 ± 72 μmol·photons/m2·s, a temperature of 20–25 °C, and three near-bed water velocity classes: low (<17.9 cm/s, moderate (17.9–32.8 cm/s, and high (>32.8 cm/s. A logistic model was applied to estimate the maximum net growth rate (μmax and carrying capacity (Bmax. A response surface method was also applied to estimate chlorophyll a (Chl-a and ash-free dry mass (AFDM with respect to the independent variables (i.e., time and water velocity. We detected both the highest μmax (1.99 d−1 and highest Bmax (7.01 mg/m2 for Chl-a at the moderate water velocity. For AFDM, we observed the highest μmax (0.57 d−1 and Bmax (1.47 g/m2 at the low and moderate velocity classes, respectively. The total algae density in the region of moderate velocity at the end of the experiment was 6.47 × 103 cells/cm2, corresponding to levels 1.7 and 1.3 times higher than those at lower and higher velocities, respectively. Our findings indicated that the moderate near-bed water velocity provided favorable conditions for algal growth and corresponding biomass accumulation.
Numerical Simulation of Entropy Growth for a Nonlinear Evolutionary Model of Random Markets
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Mahdi Keshtkar
2016-01-01
Full Text Available In this communication, the generalized continuous economic model for random markets is revisited. In this model for random markets, agents trade by pairs and exchange their money in a random and conservative way. They display the exponential wealth distribution as asymptotic equilibrium, independently of the effectiveness of the transactions and of the limitation of the total wealth. In the current work, entropy of mentioned model is defined and then some theorems on entropy growth of this evolutionary problem are given. Furthermore, the entropy increasing by simulation on some numerical examples is verified.
Growth, technology, and environmental change—nonlinearity and non-constant returns
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Wei-Bin Zhang
2002-01-01
Full Text Available This paper proposes a growth model with endogenous technology and environmental change. The economy consists of two sectors, production and environmental. The production sector produces goods with knowledge, labor, and capital as inputs under perfect competitive conditions. Knowledge accumulates through learning by doing. The environment is affected by production, consumption, the environmental sector's production efficiency, and the nature's purification. The simple model shows that it is difficult to explicitly judge the impact of factors such as environmental policy, knowledge accumulation efficiency and preference change on the environment.
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Wagner Cotroni Valenti
1993-01-01
Full Text Available In this article the length growth curves of Macrobrachium rosenbergii (De Man, 1879 held in different population densities were analysed. Postlarvae prawns were stocked into five 0,02 ha earthen ponds at densities of 4, 8, 12, 16 and 20 ind./m² during six months. Forthnightly, the mean total length of animals from each pond were obtained by means of random samples. For each population the length growth curves and the instantaneous growth rate expressions were determined. The growth rate and the asymptotic maximum length decreased with the stocking density raised. This effect is greater when the density ranges in low levels. The growth decrease can be due to intraspecific competition for life resources and to negative interactions between individuals, as aggressive or social behavior, that increase with the increase prawns density.
Paramasivam, P; Ramachandra Raja, C
2012-07-01
Single crystals of glycinium hydrogen squarate (GHS) have been successfully synthesized and purity of the material has been increased by repeated recrystallization process. Single crystals were grown by slow evaporation solution growth technique using water and ethanol as solvents at room temperature. Then the grown crystal was characterized by different techniques for finding its suitability for device fabrications. The grown crystal was characterized by single crystal XRD, powder XRD, FT-IR, UV-Vis-NIR, (1)H NMR, (13)C NMR, SHG and DTA/TGA analyses respectively. From the single crystal XRD diffraction, the crystal system was identified as monoclinic. The presence of functional groups were identified by FT-IR analysis. The UV transparency cut-off wavelength of the grown crystal occurs at 342nm. (1)H NMR and (13)C NMR spectroscopic studies were employed to elucidate the structure of the grown crystal. The second harmonic generation efficiency test by Kurtz-Perry technique showed positive result. The decomposition temperature of the grown crystal was studied by DTA/TGA analysis. The results observed from the characterization analyses show its suitability for NLO applications.
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Paula Machado dos Santos
2007-12-01
Full Text Available O ajuste de curvas de crescimento de plantas de alface durante seu ciclo necessita de amostragens no tempo, o que restringe o número de efeitos de tratamentos estudados. Com o objetivo de determinar o cronograma de amostragem de plantas de alface em hidroponia para o ajuste de curvas de crescimento até a fase de maturação das sementes, foram realizados dois cultivos em casa de vegetação durante a primavera e o outono, em área pertencente ao Departamento de Fitotecnia, na UFSM, Santa Maria, RS. A partir do ajuste de um modelo de crescimento com amostragem diária, simularam-se diferentes cronogramas de amostragem para o ajuste do mesmo modelo. Para encontrar o cronograma de maior intervalo entre amostragens, ou seja, menor número de coletas, foi comparado o ajuste do modelo de amostragem diária com os ajustes dos modelos dos diferentes intervalos de amostragens simulados, dois a dois, pelo teste F. Foram realizadas simulações considerando desde a data de transplante até a produção de sementes, para variáveis de fitomassa seca da planta e de partes da planta e área foliar. Em experimentos realizados com alface hidropônica na primavera, para o ciclo completo, recomendam-se amostragens a cada 3, 8, 20 e 9 dias para fitomassa seca relativa total da planta de alface, de folhas, de raiz e área foliar, respectivamente; enquanto que, para experimentos realizados no outono, é recomendável utilizar intervalos de amostragens a cada 2, 11, 12 e 11 dias, respectivamente.The fitting of growth curves for lettuce plants requires many samplings within o time interval, while can restrict the number of studied treatments. With the aim o determine sampling chronogram hidroponic lettuce for the fitting of growth curves until maturation of seeds. Two greenhouse trials were carried out in spring an autumn, at UFSM experimental area, Santa Maria, RS. Different sampling interval were simulated using the fitting of a daily model. The optimum sampling
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Sidinei José Lopes
2007-10-01
Full Text Available O objetivo deste trabalho foi determinar o cronograma de amostragem de plantas de alface hidropônica, para ajuste de curvas de crescimento durante o período vegetativo. Foram realizados dois cultivos de alface, variedade Regina, de 8/9/2004 a 19/11/2004 (primavera/verão e 22/2/2005 a 24/5/2005 (verão/outono, em estufas de plástico do Dep. de Fitotecnia, da UFSM, Santa Maria, RS. A partir do ajuste do modelo co-seno com amostragem diária, registrada como padrão, diferentes intervalos entre as amostragens foram simulados para o ajuste do mesmo modelo. A fim de se encontrar o intervalo adequado, foi comparada a variância de falta de ajuste do modelo de amostragem diária com as variâncias de falta de ajuste dos modelos com diferentes intervalos de amostragens pelo teste F. Os cronogramas de amostragens para ajuste de curvas de crescimento de plantas de alface sob hidroponia, para experimentos de primavera/verão e verão/outono, possuem intervalos iguais a dois dias, para fitomassa seca total da planta e da folha; intervalos de quatro dias, para fitomassa de raiz; e, diariamente, para área foliar.The objective of this work was to determinate a sampling chronology to adjust lettuce hidroponic growth curves during its vegetative development. The variety Regina was grown from September 8, 2004 until November 19, 2004 (spring/summer and February 22, 2005 until May 24, 2005 (summer/fall. Plants were placed inside a plastic covered greenhouse in Santa Maria, RS, Brazil. Based on the adjusted cosine model, daily samples were taken as standard and different sampling intervals were simulated in order to better adjust the same model. To estimate de adequate sampling interval a comparison was conducted between the variance of lack of adjustment of the daily sampling with the variance of lack of adjustment of different samplings intervals using an F test. Sampling chronograms for adjusting crop growth curves of hydroponics lettuce plants for both
Energy Technology Data Exchange (ETDEWEB)
Jaikumar, P. [PG & Research Department of Physics, National College (Autonomous), Tiruchirappalli, 620 001 Tamil Nadu (India); Sathiskumar, S. [Crystal Growth Laboratory, Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023 Tamil Nadu (India); Balakrishnan, T., E-mail: balacrystalgrowth@gmail.com [Crystal Growth Laboratory, Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023 Tamil Nadu (India); Ramamurthi, K. [Crystal Growth & Thin Film laboratory, Department of Physics & Nanotechnology, SRM University, Kattankulathur, 603 203 Kancheepuram, Tamil Nadu (India)
2016-06-15
Highlights: • Growth of bulk single crystals of cytosinium hydrogen selenite (CHS) is reported. • Dielectric constant of CHS is measured as a function of Frequency and temperature. • Lower cut off value of UV–vis-NIR spectrum of CHS crystal is observed at 210 nm. • Meyer’s index value of CHS crystal calculated identifies it as a soft material. • Powder SHG efficiency of CHS is about 1.5 times that of KDP crystal. - Abstract: A novel nonlinear optical single crystal of cytosinium hydrogen selenite was grown from aqueous solution of cytosinium hydrogen selenite by slow solvent evaporation method at room temperature. The structural properties of grown crystal have been studied by single crystal and powder X-ray diffraction analysis. Presence of various functional groups was identified from Fourier transform infrared spectroscopy. The optical transmittance and absorbance spectra were recorded by UV–vis-NIR spectrometer and the grown crystal possesses good transparency in the entire visible region. The dielectric constant and dielectric loss of the crystal were calculated as a function of frequency at different temperatures. The mechanical strength of the cytosinium hydrogen selenite crystal was estimated using Vicker’s microhardness tester. Etch patterns of the cytosinium hydrogen selenite crystal were obtained using distilled water as etchant for different etching time. Second harmonic generation efficiency tested using Nd:YAG laser is about 1.5 times that of KDP.
Bincy, I. P.; Gopalakrishnan, R.
2014-09-01
2-Aminopyridinium p-Toluenesulfonate (2APPTS), an organic NLO crystal, was grown for the first time by the slow evaporation solution technique. Single crystal X-ray diffraction analysis reveals that 2APPTS belongs to monoclinic crystal system with centrosymmetric space group P21/n. The determined lattice parameters are a=8.580(7) Å, b=6.419(5) Å, c=23.277(18) Å, β=100.016(3)° and volume=1262.58(3) Å3. Powder XRD study reveals the crystalline nature of the grown sample. FT-IR and FT-Raman studies were carried out to identify the functional groups present in 2APPTS. FT-NMR spectral study confirms the number of protons and carbon present in the molecular structure of the title compound. Thermal behavior and stability of 2APPTS were investigated by thermogravimetric (TG) and differential thermal analyses (DTA). Transparency of the title crystal in UV-vis-NIR region was analyzed and the optical band gap energy was found to be 3.6 eV. The mechanical properties of the grown crystals have been analyzed by the Vickers microhardness method. The etching studies reveal the growth pattern and dislocations present in the grown 2APPTS crystal. The negative third order nonlinear optical parameters like refractive index (n2), absorption coefficient (β) and susceptibility (χ(3)) were estimated by Z-scan studies.
Subhashini, R.; Sathya, D.; Sivashankar, V.; Latha Mageshwari, P. S.; Arjunan, S.
2016-12-01
Highly transparent solitary nonlinear semiorganic optical material Bis(L-threonine) copper (II) monohydrate [BLTCM], was synthesized by a conventional slow evaporation solution growth technique. The grown crystals were subjected to structural, optical, electrical, thermal, mechanical, SHG and Laser damage threshold studies. Single crystal XRD shows that the material crystallizes in monoclinic system with noncentrosymmetric space group P21. FT-IR and FT-RAMAN analyses confirm the various functional groups present in the grown crystal. The transparency range of BLTCM was determined by UV-vis-NIR studies and various optical constants such as extinction coefficient (K), refractive index, optical conductivity and electric susceptibility with real and imaginary parts of dielectric constant were calculated using the transmittance data which have applications in optoelectronic devices. Dielectric studies of the crystal were carried out at different frequencies and temperatures to analyze the electrical properties. TGA and DSC analyses were performed to study the thermal behaviour of the sample. The hardness stability of the grown specimen was investigated by Vickers microhardness test. The output intensity of second harmonic generation was confirmed using the Kurtz and Perry powder method. The laser induced surface damage threshold of the crystal was measured using Nd:YAG laser.
Midya, Samaresh; Duong, Alan; Thomas, Flint; Corke, Thomas
2016-11-01
Schoppa and Hussain (1998, 2002) demonstrated streak transient growth (STG) as the dominant streamwise coherent structure generation mechanism required for wall turbulence production. A novel, flush surface-mounted pulsed-DC plasma actuator was recently developed at the University of Notre Dame to actively intervene in STG. In recent high Reynolds number, zero pressure gradient turbulent boundary layer experiments, drag reduction of up to 68% was achieved. This is due to a plasma-induced near-wall, spanwise mean flow sufficient in magnitude to prevent the lift-up of low-speed streaks. This limits their flanking wall-normal component vorticity-a critical parameter in STG. Experiments also show that sufficiently large plasma-induced spanwise flow can exacerbate STG and increase drag by 80%. The ability to significantly increase or decrease drag by near-wall actuation provides an unprecedented new tool for clarifying the open questions regarding the interaction between near-wall coherent structures and those in the logarithmic region. In the reported experiments this interaction is experimentally characterized by a second-order Volterra nonlinear system model under both active suppression and enhancement of STG. Supported by NASA Langley under NNX16CL27C.
Rhudy, Jamie L; Martin, Satin L; Terry, Ellen L; Delventura, Jennifer L; Kerr, Kara L; Palit, Shreela
2012-11-01
Emotion can modulate pain and spinal nociception, and correlational data suggest that cognitive-emotional processes can facilitate wind-up-like phenomena (ie, temporal summation of pain). However, there have been no experimental studies that manipulated emotion to determine whether within-subject changes in emotion influence temporal summation of pain (TS-pain) and the nociceptive flexion reflex (TS-NFR, a physiological measure of spinal nociception). The present study presented a series of emotionally charged pictures (mutilation, neutral, erotic) during which electric stimuli at 2 Hz were delivered to the sural nerve to evoke TS-pain and TS-NFR. Participants (n=46 healthy; 32 female) were asked to rate their emotional reactions to pictures as a manipulation check. Pain outcomes were analyzed using statistically powerful multilevel growth curve models. Results indicated that emotional state was effectively manipulated. Further, emotion modulated the overall level of pain and NFR; pain and NFR were highest during mutilation and lowest during erotic pictures. Although pain and NFR both summated in response to the 2-Hz stimulation series, the magnitude of pain summation (TS-pain) and NFR summation (TS-NFR) was not modulated by picture-viewing. These results imply that, at least in healthy humans, within-subject changes in emotions do not promote central sensitization via amplification of temporal summation. However, future studies are needed to determine whether these findings generalize to clinical populations (eg, chronic pain).
Silambarasan, A.; Krishna Kumar, M.; Thirunavukkarasu, A.; Md Zahid, I.; Mohan Kumar, R.; Umarani, P. R.
2015-05-01
Organic Uronium 3-carboxy-4-hydroxybenzenesulfonate (UCHBS) nonlinear optical single crystal was grown by solution growth technique. The solubility and nucleation studies were performed for UCHBS at different temperatures 30, 35, 40, 45, 50 and 55 °C. The crystal structure of UCHBS was elucidated from single crystal X-ray diffraction study. High resolution X-ray diffraction technique was employed to study the perfection and internal defects of UCHBS crystal. Infrared and Raman spectra were recorded to analyze the vibrational behavior of chemical bonds and its functional groups. The physico-chemical changes, stability and decomposition stages of the UCHBS compound were established by TG-DTA studies. The dielectric phenomenon of UCHBS crystal was studied at different temperatures with respect to frequency. Linear optical properties of transmittance, cut-off wavelength, band gap of UCHBS were found from UV-visible spectral studies. Third-order nonlinear optical susceptibility, nonlinear refractive index, nonlinear optical absorption coefficient values were measured by Z-scan technique. The mechanical properties of UCHBS crystal was studied by using Vicker's microhardness test. The growth features of UCHBS crystal were analyzed from etching studies.
Interface-wave dispersion curves inversion based on nonlinear Bayesian theory%根据非线性贝叶斯理论的界面波频散曲线反演
Institute of Scientific and Technical Information of China (English)
李翠琳; Stan E Dosso; Hefeng Dong
2012-01-01
通过时频分析法从海底环境噪声数据中提取界面波频散曲线,进而采用非线性贝叶斯反演方法估算海底沉积物厚度、剪切波速度、压缩波速度和密度等参数及其不确定性.参数的最大后验概率(MAP)估计值和边缘概率分布分别通过自适应单纯形模拟退火法和Metropolis-Hastings采样法在各参数先验区间内搜索获得,采用贝叶斯信息准则(BIC)从不同参数化模型中选择最优模型.界面波频散曲线反演结果表明:满足实测数据的最优海底模型结构为3层均匀分布剪切波速度剖面结构,海底深度的反演精度在800 m以内,比起压缩波速度和密度,剪切波速度的不确定性更小,对界面波频散曲线更敏感.%This paper applies a dataset of ocean ambient noise data to extract interface-wave dispersion curves using time-frequency analysis. The nonlinear Bayesian inversion is applied to estimate seabed sediment parameters such as thickness, shear-wave velocity, compression wave velocity and density, and their uncertainties from interface-wave dispersion curves. The maximum a posterior (MAP) model and marginal probability distributions of parameters are estimated using posterior probability densities computed by adaptive simplex simulated annealing and Metropolis-Hastings sampling methods. The Bayesian information criterion is applied to determine the optimal model that fully explains the observed data by the different parameterizations. The inversion results indicate that 3-uniform-layer model is chosen as the preferred parameterization. The resolution of inversion is up to 800 m-depth. The shear-wave velocity and layer thickness have fewer uncertainties and are more sensitive to the interface wave dispersion than the compression wave velocity and density.
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.
Directory of Open Access Journals (Sweden)
Conceição A. M. Segre
2001-06-01
Full Text Available OBJETIVO: as curvas de percentil constituem uma das formas de avaliação do crescimento intra-uterino e podem predizer doenças do recém-nascido como também caracterizar uma população. Este trabalho teve por objetivo construir as curvas de crescimento intra-uterino dos recém-nascidos da Maternidade do Hospital Albert Einstein (MAE, hospital que atende a uma população de alto nível socioeconômico, e comparar com as curvas de crescimento intra-uterino de uma população norte-americana da Califórnia. MÉTODOS: foram construídas curvas de crescimento intra-uterino a partir do peso do recém-nascido de parto único, tomado logo após o nascimento, e da idade gestacional segundo informações maternas, a partir da 32ª. semana de idade gestacional, abrangendo os nascimentos ocorridos na MAE no período de fevereiro de 1995 a fevereiro de 1999. Foram calculados os percentis 10, 50 e 90 do peso ao nascer para cada idade gestacional e comparados com os das curvas da Califórnia. RESULTADOS: as curvas dos percentis 10 e 50 na população da MAE não diferiram das curvas da Califórnia. Para o percentil 90, a curva da MAE ficou abaixo das curvas da Califórnia. Houve número menor de pequenos e grandes para a idade gestacional (PIG e GIG quando classificados pelas curvas da Califórnia. A classificação em PIG, AIG, GIG mostrou-se relacionada significantemente com o ganho de peso materno nos dois sexos. CONCLUSÕES: as duas populações analisadas segundo as curvas de crescimento intra-uterino são diferentes entre si; deverão ser identificados fatores específicos que atuem na população da MAE.OBJECTIVE: growth curves can be used to assess intrauterine growth, to predict diseases in newborns, and to characterize different populations. The objective of this study was to obtain intrauterine growth curves of newborns from the maternity ward of the Hospital Albert Einstein (MAE and compare them with intrauterine growth curves of a population
Directory of Open Access Journals (Sweden)
Mercedes Esquivel Lauzurique
2011-03-01
Full Text Available INTRODUCCIÓN. En los últimos decenios, el sobrepeso y la obesidad han aumentado en los niños y adolescentes cubanos, por lo que son necesarios instrumentos sencillos que permitan analizar en la práctica asistencial las características y evolución de la obesidad. Por esta razón, se decidió desarrollar curvas de crecimiento de la circunferencia de la cintura en niños y adolescentes habaneros, dimensión que muestra una alta correlación con la masa grasa intraabdominal y, por ende, con un perfil lipídico aterogénico. MÉTODOS. Se estimaron valores de percentiles de esta circunferencia según grupos de edad y sexo, utilizando el método de transformación de potencia de tipo Box-Cox (BCPE, en 4 360 niños y adolescentes entre 7,5 y 19,0 años, que integraron las muestras de los estudios transversales de crecimiento y desarrollo efectuados en La Habana durante los años 1998 y 2005. RESULTADOS. La circunferencia de la cintura aumentó de forma significativa con la edad en uno y otro sexo. Los niños mostraron cifras superiores a las de las niñas y los valores que se obtuvieron tienden a ser inferiores a los reportados en otros estudios. CONCLUSIONES. Estas curvas podrían usarse provisionalmente con propósitos clínicos y epidemiológicos hasta que se disponga de referencias de carácter nacional para la identificación de niños escolares y adolescentes con riesgo de desarrollar trastornos relacionados con la adiposidad visceral.INTRODUCTION. In past decades, the excess weight and obesity have increased in Cuban children and adolescents, thus, are necessaries simple tools allowing analyzing in health practice the characteristics and evolution of obesity. By this reason, we decide to develop growth curves of waist circumference in Havanan children and adolescents, a dimension showing a high correlation with the intra-abdominal fatty mass and consequently, with an atherogenic lipid profile. METHODS. Authors estimated the percentile
Kirubagaran, R.; Madhavan, J.
2015-02-01
Single crystals of L-alanine DL-malic acid (LADLMA) have been grown from aqueous solution by slow-cooling technique. Powder X-ray diffraction studies reveal the structure of the crystal to be orthorhombic. The nonlinear optical conversion efficiency test was carried out for the grown crystals using the Kurtz powder technique. The third order nonlinear refractive index and the nonlinear absorption coefficient where evaluated by Z-scan measurements. As the material have a negative refractive index it could be used in the protection of optical sensors such as night vision devices.
Directory of Open Access Journals (Sweden)
Emilio Dela Bruna
2007-01-01
to improve the fruit quality. The correct time for fruit pruning can be defined through the knowledge of the curve of fruit growth. Fruit growth, fresh weight (PV and dry weight (PS of 20 peach varieties had been evaluated at Epagri's Agriculture Research Station of Urussanga, State of Santa Catarina, Brazil (latitude 28º31'S, altitude 48 m. The plants had been grouped in varieties of short, medium and long cycle, related to the period from budding to fruit harvest, ranging from W77 to 85 days, 86 to 109 days and more than 109 days, respectively. Weekly, from blossom to harvest, green fruits have been harvested, then weighed (PV and dehydrated in a stove at 70ºC to determine the PS. All the varieties had presented a very high initial relative growth (PS daily gain / PS total of the fruit, which was reducing until the maturation of the fruits for the varieties of short and medium cycle. However, the long cycle varieties had an increase on the relative growth in the end of the cycle. Long cycle varieties presented three stages of fruit growth, considering the PS, PV and the daily accumulation of PS and PV: Stage I, with exponential growth; Stage II, with little growth; Stage III, with exponential growth culminating with the fruit maturation. On the other hand, varieties of medium and short cycle had not presented the Stage II, with little growth, switching directly from Stage I to Stage III.
Maulana, Ridwan; Opdenakker, Marie-Christine; Stroet, Kim; Bosker, Roel
2013-09-01
Research consistently shows that the learning environment plays an important role for early adolescents' learning and outcomes and suggests that good teacher-student relationships can serve as a protective factor for maintaining young adolescents' interest and active engagement in learning. However, less is known about the dynamic nature of teacher-student relationships and how they link with academic motivation development. Furthermore, little is known about the nature and the effects of teacher-student relationships in a cross-national context. The present study investigated changes in two components of teacher-student relationships (teachers' involvement vs. rejection) and examined links with students' academic motivation during the first grade of secondary school. Ten Dutch and ten Indonesian teachers (65 % female) from 24 classes were videoed 12 times across the school year, and four videos for each class were selected randomly and coded on teachers' involvement versus rejection. A total of 713 students (52 % girls) completed four-wave measures of their academic motivation after each video observation. Multilevel growth curve modeling revealed that the teacher's involvement changed in a curvilinear way and decreased across the first year of secondary education, while changes in the teacher's rejection did not follow a linear time function. Academic motivation changed in an undesirable way: controlled motivation increased, while autonomous motivation decreased over time. Teachers' involvement had a unique contribution in preventing high levels of controlled motivation in both countries. Findings suggest that teacher-student relationships (teachers' involvement) play an essential role in early adolescents' motivation regardless of the nations and should be a priority for schools.
Al Ghriwati, Nour; Sutter, Megan; Pierce, Bradford S; Perrin, Paul B; Wiechman, Shelley A; Schneider, Jeffrey C
2017-05-05
To use latent growth curve and longitudinal structural equation modeling to examine the 2-year trajectory of satisfaction with appearance in adults with burn injury, and that trajectory's effect on depression 5 years after burn injury. Data were collected at discharge after burn injury hospitalization and at 6 months, 1 year, 2 years, and 5 years postdischarge. The Burn Model Systems (BMS) program consisted of a data center and 5 participating burn centers. The sample consisted of adults (N=720) who were hospitalized for a burn injury, enrolled in the BMS database, and completed measures at least once throughout the 5-year study duration. Not applicable. Satisfaction With Appearance Scale and Patient Health Questionnaire-9 (depression). Women with burn injury reported higher levels of dissatisfaction with their appearance in comparison to their male counterparts over the 2 years after discharge. Individuals with a larger total body surface area (TBSA) affected by a burn also reported greater body dissatisfaction across the postdischarge 2-year period. Results did not support significant gender or TBSA differences in the rate of change of body dissatisfaction trajectories across these 2 years. Individuals with greater body dissatisfaction at 6 months postdischarge tended to have higher depressive symptoms at 5 years. Six month postdischarge, body dissatisfaction scores also mediated the effects of gender and TBSA on depressive symptoms 5 years later. It is recommended that individuals with heightened body image dissatisfaction after a burn, particularly women and those with larger TBSA, participate in evidence-based psychosocial interventions to improve long-term adjustment. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.
Modeling growth of mandibles in the Western Arctic caribou herd
Directory of Open Access Journals (Sweden)
Jay M. Ver Hoef
2001-03-01
Full Text Available We compared growth curves for ramus length and diastema length from two autumn collections of mandibles of male Western Arctic Herd caribou in Alaska. We were primarily interested in determining if growth curves of caribou mandibles differed between caribou born during 1959-1967, after the herd had been high for several years and was probably declining in size, and those born during 1976-1988, when the herd was increasing in size. To compare these growth curves, we used a nonlinear model and used maximum likelihood estimates and likelihood ratio tests. We found that growth rates were similar between periods, but intercepts and variances of growth curves differed. From this we infer that calves were smaller in autumn during the 1960s and that significant compensatory growth did not occur later in life.
Growth, dielectric and nonlinear optical properties of Li3Cs2B5O10 single crystals
Sukumar, M.; Ramesh Babu, R.; Ramamurthi, K.
2017-01-01
Lithium cesium borate (Li3Cs2B5O10), an alkali metal borate, single crystals were grown by Czochralski method. Chemical etching was performed on grown Li3Cs2B5O10 crystal at various regions. The observed dislocation densities are varied at different regions of the grown Li3Cs2B5O10 crystal. Dielectric behavior of Li3Cs2B5O10 crystal at different temperatures is studied. The third-order nonlinear optical parameters of lithium cesium borate crystal are determined by Z-scan technique. The nonlinear refractive index ( n 2) value is estimated to be -7.272 × 10-11 cm2/W, and the corresponding third-order nonlinear susceptibility ( χ 3) is estimated to be 4.19 × 10-9 esu. The measured nonlinear refractive indices reveal the self-defocusing effect of Li3Cs2B5O10 crystal.
Institute of Scientific and Technical Information of China (English)
栗冬梅; 苗志刚; 宋秀平; 王君; 刘起勇
2012-01-01
[目的]应用一种昆虫细胞培养基作为基础成分培养巴尔通体(Bartonella species),建立一种操作方便、高效稳定的巴尔通体液体培养方法.[方法]昆虫细胞培养基中添加10％胎牛血清,以此为基础培养液分别添加蔗糖和谷氨酰胺,比较这两种成分对汉赛巴尔通体(B.henselae)和五日热巴尔通体(B.quintana)生长的影响并观察其他10种巴尔通体在简化后的培养液中的生长特性.[结果]添加蔗糖和谷氨酰胺不会明显促进巴尔通体的生长,10种巴尔通体在简化后的培养液中均生长良好.不同种巴尔通体生长曲线不同,汉赛巴尔通体和五日热巴尔通体的世代时间分别为5.2 h和4.3 h,生长速度快于固体培养.[结论]以昆虫细胞培养基作为基础成分的培养液适于巴尔通体液体培养,特别是对一些更难培养的巴尔通体提供了一种较好的培养方法.%[Objective] We tested an insect cells-based liquid medium and its utility for the easy-to-maintain, fast and reliable system for cultivation of different Bartonella.[Methods] Media composition and growth conditions were optimized using B.henselae and B.quintana.The growth curves of the other ten Bartonella species were determined using the optimized liquid medium.[Results] Glutamine and sucrose supplements did not affect significantly the growth rate of these bacteria.A generation time of 5.2 h for B.henselae and 4.3 h for B.quintana was estimated during the exponential phase of the growth curve occurred between days 1 and 2 after inoculation.The twelve medical and veterinary important Bartonella species grew well under conditions established and each exhibited unique growth characteristics.[Conclusion] This liquid growth medium may provide an advantage over conventional direct blood agar plating for analyzing Bartonella properties including antibiotic susceptibility and resistance and pathogeniciry.
Arivazhagan, T.; Siva Bala Solanki, S.; Rajesh, Narayana Perumal
2017-02-01
The butyl 4-hydroxybenzoate single crystal has been grown by vertical Bridgman technique using single wall ampoule. The cell parameters of the grown crystal are verified by single crystal X-ray diffraction analysis. The functional groups of the grown crystal were identified by Fourier transform infrared analysis. The melting, decomposition and crystallization point of the compound are determined by thermo gravimetric analysis and differential scanning calorimetric analysis. The mechanical properties of the grown crystal has been analyzed by Vickers microhardness method. The optical behavior of the grown crystal has been observed by UV-vis-NIR transmission spectroscopic analysis which shows that the lower cut-off wavelength lying at 293 nm and found that the energy band gap value is 4.05 eV. The blue light emission of the crystal was identified by photoluminescence studies. The positive third order nonlinear optical parameters like nonlinear refractive index (n2), nonlinear absorption co-efficient (β) and third order nonlinear susceptibility (χ3) of the grown crystal was calculated by Z-scan studies. The positive sign of nonlinear refractive index (n2) indicates that the crystal exhibits self focusing optical nonlinearity. The crystal exhibits good optical power limiting behavior.
Ageing of the nonlinear optical susceptibility in soft matter
Energy Technology Data Exchange (ETDEWEB)
Ghofraniha, N [SMC-INFM-CNR, c/o Universita di Roma ' La Sapienza' , Piazzale Aldo Moro 2, 00185, Rome (Italy); Conti, C [Research Centre ' Enrico Fermi' , Via Panisperna 89/A, 00184 Rome (Italy); Leonardo, R Di [SOFT-INFM-CNR, c/o Universita di Roma ' La Sapienza' , Piazzale Aldo Moro 2, 00185, Rome (Italy); Ruzicka, B [SOFT-INFM-CNR, c/o Universita di Roma ' La Sapienza' , Piazzale Aldo Moro 2, 00185, Rome (Italy); Ruocco, G [SOFT-INFM-CNR, c/o Universita di Roma ' La Sapienza' , Piazzale Aldo Moro 2, 00185, Rome (Italy)
2007-05-23
We investigate the nonlinear optics response of a colloidal dispersion undergoing dynamics slowing down with age, by using Z-scan and dynamic light scattering measurements. We study the high optical nonlinearity of an organic dye (rhodamine B) dispersed in a water-clay (laponite) suspension. We consider different clay concentrations (2.0-2.6 wt%) experiencing dynamics arrest. We find that (i) the concentration dependent exponential growth of both mean relaxation time and nonlinear absorption coefficient can be individually scaled to a master curve and (ii) the scaling times are the same for the two physical quantities. These findings indicate that the optical nonlinear susceptibility exhibits the same ageing universal scaling behaviour, typical of disordered out of equilibrium systems.
Energy Technology Data Exchange (ETDEWEB)
Divya Bharathi, M.; Ahila, G.; Mohana, J. [Department of Physics, Presidency College, Chennai 600005 (India); Chakkaravarthi, G. [Department of Physics, CPCL Polytechnic College, Chennai 600068 (India); Anbalagan, G., E-mail: anbu24663@yahoo.co.in [Department of Nuclear Physics, University of Madras, Chennai 600025 (India)
2017-05-01
A neoteric organic third order nonlinear optical material 8-hydroxyquinolinium 2-chloro-5-nitrobenzoate dihydrate (8HQ2C5N) was grown by slow cooling technique using ethanol: water (1:1) mixed solvent. The calculated low value of average etch pit solidity (4.12 × 10{sup 3} cm{sup −2}) indicated that the title crystal contain less defects. From the single crystal X-ray diffraction data, it was endowed that 8HQ2C5N crystal belongs to the monoclinic system with centrosymmetric space group P2{sub 1}/c and the cell parameters values, a = 9.6546 (4) Ǻ, b = 7.1637(3) Ǻ, c = 24.3606 (12) Ǻ, α = γ = 90°, β = 92.458(2)° and volume = 1683.29(13) Ǻ{sup 3}. The FT-IR and FT-Raman spectrum were used to affirm the functional group of the title compound. The chemical structure of 8HQ2C5N was scrutinized by {sup 13}C and {sup 1}H NMR spectral analysis and thermal stability through the differential scanning calorimetry study. Using optical studies the lower cut-off wavelength and optical band gap of 8HQ2C5N were found to be 364 nm and 3.17 eV respectively. Using the single oscillator model suggested by Wemple – Didomenico, the oscillator energy (E{sub o}), the dispersion energy (E{sub d}) and static dielectric constant (ε{sub o}) were estimated. The third-order susceptibility were determined as Im χ{sup (3)} = 2.51 × 10{sup −5} esu and Re χ{sup (3)} = 4.46 × 10{sup −7} esu. The theoretical third-order nonlinear optical susceptibility χ{sup (3)} was calculated and the results were compared with experimental value. Photoluminescence spectrum of 8HQ2C5N crystal showed the yellow emission. The crystal had the single shot laser damage threshold of 5.562 GW/cm{sup 2}. Microhardness measurement showed that 8HQ2C5N belongs to a soft material category. - Highlights: • A new organic single crystals were grown and the crystal structure was reported. • Crystal possess, good transmittance, thermal and mechanical stability. • Single shot LDT value is found to be
Institute of Scientific and Technical Information of China (English)
刘俊升; 周颖; 李丹
2013-01-01
Loneliness is typically defined as the subjective experience of dissatisfaction with one's social and relational life. Children as young as preschool-age can reliability report feelings of loneliness. The experience of loneliness is associated with a wide range of socio-emotional difficulties from early childhood to adolescence. Most previous research has focused on contributing factors and mechanisms that may underlie the development of loneliness. However, much less is known about the developmental trajectories of loneliness, particularly during middle childhood. It has been postulated that loneliness arises as a result of unmet social needs (Social needs theory). From a cognitive perspective, loneliness is thought to be influenced primarily by subjective perceptions of one's personal relationships. However, children's social needs and cognitive capabilities do not remain static across development. Accordingly, the purpose of the present study was to examine the developmental trajectories of loneliness across middle childhood. Participants were 884 primary school students, who were followed up for three years from grade two to grade five. Assessments of children's loneliness and peer acceptance were obtained from both self-reports and peer assessments at four time points. Latent growth modeling was used to examine: (1) initial levels and change in loneliness over time; and (2) the prediction of both initial levels and growth in loneliness from child gender and peer acceptance. Among the results, children's loneliness decreased in a non-linear trajectory from grade 2 (Mean age = 8.5years, SD=3.06 months) to grade 5. As well, although boys had higher initial levels of loneliness than girls, there was no gender difference in the change of loneliness over time. Finally, results from latent growth curve modeling indicated that peer acceptance as a time-variant variable influenced children's feeling of loneliness. Peer acceptance at given testing point could reduce
Silambarasan, A.; Krishna Kumar, M.; Thirunavukkarasu, A.; Mohan Kumar, R.; Umarani, P. R.
2015-01-01
An organic nonlinear optical bulk single crystal, Ammonium 3-carboxy-4-hydroxy benzenesulfonate monohydrate (ACHBS) was successfully grown by solution growth technique. Single crystal X-ray diffraction study confirms that, the grown crystal belongs to P21/c space group. Powder X-ray diffraction and high resolution X-ray diffraction analyses revealed the crystallinity of the grown crystal. Infrared spectral analysis showed the vibrational behavior of chemical bonds and its functional groups. The thermal stability and decomposition stages of the grown crystal were studied by TG-DTA analysis. UV-Visible transmittance studies showed the transparency region and cut-off wavelength of the grown crystal. The third-order nonlinear optical susceptibility of the grown crystal was estimated by Z-scan technique using Hesbnd Ne laser source. The mechanical property of the grown crystal was studied by using Vicker's microhardness test.
Saturation process of nonlinear standing waves
Institute of Scientific and Technical Information of China (English)
马大猷; 刘克
1996-01-01
The sound pressure of the nonlinear standing waves is distorted as expected, but also tends to saturate as being found in standing-wave tube experiments with increasing sinusoidal excitation. Saturation conditions were not actually reached, owing to limited excitation power, but the evidence of tendency to saturation is without question. It is the purpose of this investigation to find the law of saturation from the existing experimental data. The results of curve fitting indicate that negative feedback limits the growth of sound pressure with increasing excitation, the growth of the fundamental and the second harmonic by the negative feedback of their sound pressures, and the growth of the third and higher harmonics, however, by their energies (sound pressures squared). The growth functions of all the harmonics are derived, which are confirmed by the experiments. The saturation pressures and their properties are found.
Energy Technology Data Exchange (ETDEWEB)
Nageshwari, M.; Jayaprakash, P.; Kumari, C. Rathika Thaya [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604407, Tamil Nadu (India); Vinitha, G. [Department of Physics, School of Advanced Sciences, VIT Chennai, 600127 Tamil Nadu (India); Caroline, M. Lydia, E-mail: lydiacaroline2006@yahoo.co.in [PG & Research Department of Physics, Arignar Anna Govt. Arts College, Cheyyar 604407, Tamil Nadu (India)
2017-04-15
An efficient nonlinear optical semiorganic material L-valinium L-valine chloride (LVVCl) was synthesized and grown-up by means of slow evaporation process. Single crystal XRD evince that LVVCl corresponds to monoclinic system having acentric space group P2{sub 1}. The diverse functional groups existing in LVVCl were discovered with FTIR spectral investigation. The UV-Visible and photoluminescence spectrum discloses the optical and electronic properties respectively for the grown crystal. Several optical properties specifically extinction coefficient, reflectance, linear refractive index, electrical and optical conductivity were also determined. The SEM analysis was also carried out and it portrayed the surface morphology of LVVCl. The calculated value of laser damage threshold was 2.59 GW/cm{sup 2}. The mechanical and dielectric property of LVVCl was investigated employing microhardness and dielectric studies. The second and third order nonlinear optical characteristics of LVVCl was characterized utilizing Kurtz Perry and Z scan technique respectively clearly suggest its suitability in the domain of optics and photonics. - Graphical abstract: Good quality transparent single crystals of L-valinium L-valine chloride single crystal was grown by slow evaporation technique. The grown crystals were analyzed using different instrumentation methods to check its usefulness for the device fabrication. The determination of nonlinear refractive index (n{sub 2}), absorption coefficient (β) and third order nonlinear susceptibility was determined by Z scan technique, highlighted that LVVCl can serve as a promising candidate for opto electronic and nonlinear optical applications.
Devi, S. Reena; Kalaiyarasi, S.; Zahid, I. MD.; Kumar, R. Mohan
2016-11-01
An ionic organic optical crystal of 4-methylpyridinium p-nitrophenolate was grown from methanol by slow evaporation method at ambient temperature. Powder and single crystal X-ray diffraction studies revealed the crystal system and its crystalline perfection. The rocking curve recorded from HRXRD study confirmed the crystal quality. FTIR spectral analysis confirmed the functional groups present in the title compound. UV-visible spectral study revealed the optical window and band gap of grown crystal. The thermal, electrical and surface laser damage threshold properties of harvested crystal were examined by using TGA/DTA, LCR/Impedance Analyzer and Nd:YAG laser system respectively. The third order nonlinear optical property of grown crystal was elucidated by Z-scan technique.
Pescarmona, G P; Scalerandi, M; Delsanto, P P; Condat, C A
1999-12-01
A new approach for modelling the spatio-temporal evolution of tumors is presented. To test its validity, a very basic model is considered, which, in spite of its simplicity, is capable of generating a multiplicity of morphologies and growth and migration rates. From an in-vivo scenario of basic life processes, cancer cell proliferation is described as a competition for basic nutrients. The chosen mathematical treatment and simulation techniques permit a direct implementation of the local nonlinear couplings existing between the various cell populations and the free and bound nutrient concentration. A discussion of the results and proposed improvements and applications of the model is also presented.
Nonlinear hyperbolic waves in multidimensions
Prasad, Phoolan
2001-01-01
The propagation of curved, nonlinear wavefronts and shock fronts are very complex phenomena. Since the 1993 publication of his work Propagation of a Curved Shock and Nonlinear Ray Theory, author Phoolan Prasad and his research group have made significant advances in the underlying theory of these phenomena. This volume presents their results and provides a self-contained account and gradual development of mathematical methods for studying successive positions of these fronts.Nonlinear Hyperbolic Waves in Multidimensions includes all introductory material on nonlinear hyperbolic waves and the theory of shock waves. The author derives the ray theory for a nonlinear wavefront, discusses kink phenomena, and develops a new theory for plane and curved shock propagation. He also derives a full set of conservation laws for a front propagating in two space dimensions, and uses these laws to obtain successive positions of a front with kinks. The treatment includes examples of the theory applied to converging wavefronts...
Institute of Scientific and Technical Information of China (English)
周文莉; 万杏花; 赵彦红
2016-01-01
Objective: To let parents understand the physical growth law of children in real time, and reasonably assess children’s growth and development through the parents participating in the individual child growth curve drawing.Methods:From July 2012 to June 2013, 1 571 children between 0 and 6 months were selected in Changning District with the method of cluster random sampling. The parents were trained to participate in children growth curve drawing and guided to understand children growth in real time. After a year, the assessment forms of children growth curve drawn by the parents who participated in were analyzed.Results: According to the weight growth curve of age measurement, the percentage of children < P3 percentile decreased(P<0.05). According to the weight growth curve of height measurement, the percentage of children < P10 percentile decreased(P<0.05). The percentage of children of P50-80 and P80-97 percentiles increased(P<0.05).Conclusion: Guiding the parents to participate in the drawing of the growth curve of the children not only enables them to understand the situation of children’s growth and development in real time, but also is more conducive to promoting the growth and development of children.%目的：通过由家长参与的个体儿童生长曲线图绘制，让家长实时了解儿童的体格生长规律，合理评估儿童的生长发育。方法：于2012年7月到2013年6月采取整群随机抽样方法，抽取长宁区0~6个月儿童1571人，培训家长参与儿童生长曲线图的绘制，指导家长实时了解儿童生长发育情况，并在1年后分析家长参与绘制儿童生长曲线图评估表。结果：按年龄测体重生长曲线图看，＜P3百分位数的儿童百分比减少（P＜0.05)；按身高测体重生长曲线图看，＜P10百分位数的儿童百分比减少（P＜0.05），P50-80和P80-97百分位数的儿童百分比增加（P＜0.05）。结论：指导家长参与儿童生长曲线图的绘制
Indian Academy of Sciences (India)
Srinivasan Bikshandarkoil R; Fernandes Royle
2016-03-01
In {\\it Pramana – J. Phys. } 75, 683 (2010), Gunasekaran et al reported that they have grown the nonlinear optical crystals, urea thiourea mercuric chloride (UTHC) and urea thiourea mercuric sulphate (UTHS).We argue that UTHC and UTHS are dubious crystals and are not what the authors propose.
Jayaprakash, P.; Sangeetha, P.; Kumari, C. Rathika Thaya; Caroline, M. Lydia
2017-08-01
A nonlinear optical bulk single crystal of L-methionine admixtured D-mandelic acid (LMDMA) has been grown by slow solvent evaporation technique using water as solvent at ambient temperature. The crystallized LMDMA single crystal subjected to single crystal X-ray diffraction study confirmed monoclinic system with the acentric space group P21. The FTIR analysis gives information about the modes of vibration in the various functional groups present in LMDMA. The UV-visible spectral analysis assessed the optical quality and linear optical properties such as extinction coefficient, reflectance, refractive index and from which optical conductivity and electric susceptibility were also evaluated. The frequency doubling efficiency was observed using Kurtz Perry powder technique. A multiple shot laser was utilized to evaluate the laser damage threshold energy of the crystal. Discrete thermodynamic properties were carried out by TG-DTA studies. The hardness, Meyer's index, yield strength, elastic stiffness constant, Knoop hardness, fracture toughness and brittleness index were analyzed using Vickers microhardness tester. Layer growth pattern and the surface defect were examined by chemical etching studies using optical microscope. Fluorescence emission spectrum was recorded and lifetime was also studied. The electric field response of crystal was investigated from the dielectric studies at various temperatures at different frequencies. The third-order nonlinear optical response in LMDMA has been investigated using Z-scan technique with He-Ne laser at 632.8 nm and nonlinear parameters such as refractive index (n2), absorption coefficient (β) and susceptibility (χ3) investigated extensively for they are in optical phase conjucation, high-speed optical switches and optical dielectric devices.
Nirosha, M; Kalainathan, S; Sarveswari, S; Vijayakumar, V; Srikanth, A
2015-02-25
Single crystal of 1-(2-Methyl-6-nitro-4-phenyl-3-quinolyl) ethanone was grown using slow evaporation solution growth technique. Single crystal X-ray diffraction study reveals the lattice parameters of the grown crystal. The modes of vibration of different molecular groups present in 2M6NQE were identified by FTIR spectral analysis. Its optical behavior was examined through UV-vis-NIR absorption and PL emission spectrum. They signify that the crystal has transparency in the region between 383 and 1100 nm. The PL spectrum of the title compound shows green emission in the crystal. From the thermal analysis, 2M6NQE has found to be thermally stable up to 263°C, and the melting point of the material is 170°C. The estimations of third order non-linear optical properties like non-linear absorption coefficient (β), non-linear refractive index (n2) and susceptibility [χ(3)] were calculated using Z-scan technique. It has observed that, crystal exhibits reverse saturation absorption and self-defocusing performance. Etching study was carried out for the grown crystal using different solvents. Copyright © 2014 Elsevier B.V. All rights reserved.
Manimekalai, R.; Antony Joseph, A.; Ramachandra Raja, C.
2014-03-01
This article has been retracted: please see Elsevier Policy on Article Withdrawal. This article has been retracted at the request of authors. According to the author we have reported Aloevera Amino Acid added Lithium sulphate monohydrate [AALSMH] crystal is a new nonlinear optical crystal. From the recorded high performance liquid chromatography spectrum, by matching the retention times with the known compounds, the amino acids present in our extract are identified as homocystine, isoleucine, serine, leucine and tyrosine. From the thin layer chromatography and colorimetric estimation techniques, presence of isoleucine was identified and it was also confirmed by NMR spectrum. From the above studies, we came to conclude that AALSMH is new nonlinear optical crystal. After further investigation, lattice parameter values of AALSMH are coinciding with lithium sulphate. Therefore we have decided to withdraw our paper. Sorry for the inconvenience and time spent.
Energy Technology Data Exchange (ETDEWEB)
Sivakumar, B.; Mohan, R. [Preidency College, Bangalore (India); Raj, S. Gokul [RR and Dr. SR Technical Univ., Avadi (India); Kumar, G. Ramesh [Anna Univ., Arni (India)
2012-11-15
Single crystals of lithium potassium phthalate (LiKP) were successfully grown from aqueous solution by solvent evaporation technique. The grown crystals were characterized by single crystal X-ray diffraction. The lithium potassium phthalate C{sub 16} H{sub 12} K Li{sub 3} O{sub 11} belongs to triclinic system with the following unit-cell dimensions at 298(2) K; a = 7.405(5) A; b = 9.878(5) A; c = 13.396(5) A; α = 71.778(5) .deg.; β = 87.300(5) .deg.; γ = 85.405(5) .deg.; having a space group P1. Mass spectrometric analysis provides the molecular weight of the compound and possible ways of fragmentations occurs in the compound. Thermal stability of the crystal was also studied by both simultaneous TGA/DTA analyses. The UV-Vis-NIR spectrum shows a good transparency in the whole of Visible and as well as in the near IR range. Third order nonlinear optical studies have also been studied by Z-scan technique. Nonlinear absorption and nonlinear refractive index were found out and the third order bulk susceptibility of compound was also estimated.
Saravanan, M.; Abraham Rajasekar, S.
2016-04-01
The crystals (benzaldehyde 4-nitro phenyl hydrazone (BPH)) appropriate for NLO appliance were grown by the slow cooling method. The solubility and metastable zone width measurement of BPH specimen was studied. The material crystallizes in the monoclinic crystal system with noncentrosymmetric space group of Cc. The optical precision in the whole visible region was found to be excellent for non-linear optical claim. Excellence of the grown crystal is ascertained by the HRXRD and etching studies. Laser Damage Threshold and Photoluminescence studies designate that the grown crystal contains less imperfection. The mechanical behaviour of BPH sample at different temperatures was investigated to determine the hardness stability of the grown specimen. The piezoelectric temperament and the relative Second Harmonic Generation (for diverse particle sizes) of the material were also studied. The dielectric studies were executed at varied temperatures and frequencies to investigate the electrical properties. Photoconductivity measurement enumerates consummate of inducing dipoles due to strong incident radiation and also divulge the nonlinear behaviour of the material. The third order nonlinear optical properties of BPH crystals were deliberate by Z-scan method.
Statistical evaluation of mathematical models for microbial growth
Lopez, S.; Prieto, M.; Dijkstra, J.; Dhanoa, M.S.; France, J.
2004-01-01
The aim of this study was to evaluate the suitability of several mathematical functions for describing microbial growth curves. The nonlinear functions used were: three-phase linear, logistic, Gompertz, Von Bertalanffy, Richards, Morgan, Weibull, France and Baranyi. Two data sets were used, one comp
Growth curves for breastfed infants in rural areas%农村母乳喂养0～12月龄婴儿体格生长百分位曲线研究
Institute of Scientific and Technical Information of China (English)
中国母乳喂养婴儿生长速率监测研究组
2013-01-01
Objective To construct the growth percentile curves of weight,length and head circumference-for-age for breastfeed infants in rural areas,and take them as the reference standards to evaluate growth of breastfed infants in rural areas.Method The data collected in the Longitudinal Study of Chinese Breasffed Infants Growth and Development from birth to 12 months of age in 6 well-being rural areas were used.The MLwiN2.25 was selected to construct the multilevel model to estimate the predicted values,and fit the percentiles reference curves (P3,P15,P50,P85,and P97) of weight,length and head circumference-for-age.The results of this study were compared with those of the Nine-city growth reference percentiles curves in China and with WHO growth reference percentiles curves.Result The percentiles reference curves of weight,length and head circumference-for-age for breastfeeding infants aged 0-12 months in rural areas were developed.Compared with the Nine-city growth reference,the P3 curves of weight-for-age and girls' length-for-age were higher by 0.02-0.39 kg,0-0.42 kg and 0.27-1.15 cm.Compared with the WHO growth reference,the P3 curves of boys and girls were both at a high level.It was estimated that using Nine-city growth reference percentiles curves to evaluate the infants in rural areas could reduce the rates of underweight and girls' stunting; and using WHO growth reference percentiles curves could reduce all infants' underweight rates.Conclusion The growth percentiles reference curves which were constructed by the longitudinal observational data and scientific method would have great significance in reflecting the development of breastfed infants,evaluating and guiding infants' growth in rural areas.%目的 制定农村母乳喂养婴儿0～12月龄年龄别体重、身长和头围的百分位参考值及生长曲线图.方法 应用“中国母乳喂养婴儿生长速率监测及标准值研究”中农村母乳喂养婴儿0～12月龄体格发
Okamoto, Kyosuke; Tsuno, Seiji
2015-10-01
In the earthquake early warning (EEW) system, the epicenter location and magnitude of earthquakes are estimated using the amplitude growth rate of initial P-waves. It has been empirically pointed out that the growth rate becomes smaller as epicentral distance becomes far regardless of the magnitude of earthquakes. So, the epicentral distance can be estimated from the growth rate using this empirical relationship. However, the growth rates calculated from different earthquakes at the same epicentral distance mark considerably different values from each other. Sometimes the growth rates of earthquakes having the same epicentral distance vary by 104 times. Qualitatively, it has been considered that the gap in the growth rates is due to differences in the local heterogeneities that the P-waves propagate through. In this study, we demonstrate theoretically how local heterogeneities in the subsurface disturb the relationship between the growth rate and the epicentral distance. Firstly, we calculate seismic scattered waves in a heterogeneous medium. First-ordered PP, PS, SP, and SS scatterings are considered. The correlation distance of the heterogeneities and fractional fluctuation of elastic parameters control the heterogeneous conditions for the calculation. From the synthesized waves, the growth rate of the initial P-wave is obtained. As a result, we find that a parameter (in this study, correlation distance) controlling heterogeneities plays a key role in the magnitude of the fluctuation of the growth rate. Then, we calculate the regional correlation distances in Japan that can account for the fluctuation of the growth rate of real earthquakes from 1997 to 2011 observed by K-NET and KiK-net. As a result, the spatial distribution of the correlation distance shows locality. So, it is revealed that the growth rates fluctuate according to the locality. When this local fluctuation is taken into account, the accuracy of the estimation of epicentral distances from initial P
Institute of Scientific and Technical Information of China (English)
马树才; 李国柱
2006-01-01
@@ 一、引言 关于经济增长与环境污染之间的关系,国内外很多学者进行了大量研究.1992年,美国经济学家G·Grossman和A·Kureger对此提出了一个环境Kuznets曲线(Environment Kuznets Curve,EKC)的假设[1].
DEFF Research Database (Denmark)
Brünner, N; Spang-Thomsen, M; Vindeløv, L
1983-01-01
The effect of 17 beta-oestradiol on a "receptor positive" and on a "receptor negative" human breast carcinoma grown in nude mice was studied. Experimental growth data were used to determine the effect on tumour growth. Flow cytometric DNA analysis (FCM) performed on tumour tissue obtained...
Lerner, Matthew D; Lonigan, Christopher J
2016-04-01
Despite the importance of phonological awareness for the development of reading in alphabetic languages, little attention has been paid to its developmental origins. In this study, dual-process, latent growth models were used to examine patterns of bidirectional relations between letter knowledge and phonological awareness during preschool. The sample comprised 358 children (mean age=48.60 months, SD=7.26). Growth models were used to quantify the unique longitudinal relations between the initial level of each skill and growth in the other skill during the preschool year, after controlling for initial level of the same skill, vocabulary, age, and growth in the code-related skill being used as a predictor. Letter-name knowledge and phonological awareness were bidirectionally related; the initial level of each uniquely predicted growth in the other. Initial letter-sound knowledge and phonological awareness growth were not uniquely related, and vocabulary was not related to growth in phonological awareness. These findings extend the evidence of the relation between letter knowledge and phonological awareness to supra-phonemic tasks, indicating that this bidirectional relation begins at an earlier point in the development of phonological awareness than previously reported. In addition, these findings help to rule out general growth in letter knowledge and phonological awareness as an alternative explanation for the bidirectional relation between these two code-related skills. Copyright © 2015 Elsevier Inc. All rights reserved.
Measurement of growth curve in F1 generation of Rongshui miniature pig%融水小型猪 F1代生长研究
Institute of Scientific and Technical Information of China (English)
施赫赫; 陈淦; 刘运忠; 刘科; 邝少松; 任海涛; 余细勇; 唐小江
2015-01-01
目的：测定融水小型猪F1代体重和体尺。方法选取F1代融水小型猪83头（雌性48头，雄性35头），测定初生至12月龄的体重、体长、体高、胸围、胸宽、胸深、管围、腿围、嘴裂长度共9个生长发育指标，并应用SPSS统计软件和Logistic非线性生长模型进行分析。结果融水小型猪F1代的初生体重雌雄分别为0.61±0.14 kg和0.55±0.13 kg，6月龄体重雌雄分别为17.21±5.20 kg和16.35±5.23 kg，12月龄体重雌雄分别为26.97±6.49 kg和26.53±5.65 kg。雌雄比较，9项指标所测结果接近，除了初生体重和体长、10月龄胸宽有差异（ P ＜0.05），其余指标同月龄雌雄之间均无明显差异。应用Logistic模型分析，体重生长拐点在5～6月龄间，体长和腿围生长拐点在2～3月龄间，体高、胸围、胸宽、胸深、管围和嘴裂长度的生长拐点在1～2月龄间。结论融水小型猪F1代成年体重轻，性情温顺，具备培养成实验用小型猪基本条件。%Objective To measure the body weight and body size of the F1 generation in Rongshui miniature pig ( RMP ).Methods 83 F1 generations of RMPs (48 females and 35 males) were selected randomly.9 traits included body-weight, body-length, body-height, chest-circumference, chest-breadth, chest-depth, circum of pastern, girth of leg and rictus were measured, and analyzed statistically by SPSS statistical software and Logistic nonlinear growth analysis model.Results In the F1 generations of RMP, the weights of birth day、6thmonth and 12th month of female and male were 0.61 ±0.14 kg and 0.55 ±0.13 kg, 17.21 ±5.20 kg and 16.35 ±5.23 kg, 26.97 ±6.49 kg and 26.53 ±5.65 kg respectively.There was no difference significantly between the genders of the 9 measured traits except for born-weight, born-length and chest-breadth in 10th month ( P <0.05 ).According to the analysis in Logistic model, body-weight inflection point was between 5th -6th month, body length
Vibrational Analysis of Curved Single-Walled Carbon Nanotube on a Pasternak Elastic Foundation
DEFF Research Database (Denmark)
Mehdipour, I.; Barari, Amin; Kimiaeifar, Amin
2012-01-01
. By utilizing He’s Energy Balance Method (HEBM), the relationships of the nonlinear amplitude and frequency were expressed for a curved, single-walled carbon nanotube. The amplitude frequency response curves of the nonlinear free vibration were obtained for a curved, single-walled carbon nanotube embedded...
Saripalli, Ravi Kiran; Bhat, H. L.; Elizabeth, Suja
2016-09-01
Bulk, transparent organic nonlinear optical (NLO) single-crystals of imidazolium L-Ascorbate (ImLA) were grown using slow-evaporation. Crystal structure was determined by single crystal X-ray diffraction analysis. Preliminary linear optical measurements through UV-Visible and infrared spectroscopy revealed good optical transmittance and a low near-UV cutoff wavelength at 256 nm. Kurtz and Perry powder test revealed that ImLA is a phase-matchable NLO material with a second harmonic generation (SHG) efficiency of 1.2 times larger than that of standard KH2PO4 (KDP). Laser damage thresholds were determined for ImLA.
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.
Institute of Scientific and Technical Information of China (English)
张卫婷
2015-01-01
微生物在发酵期间使用不同发酵技术中遭遇的突变问题越来越多，极易造成设备中原件的损坏，对微生物发酵的研究造成很大的弊端。为此，提出发酵微生物的不同温度生长变化曲线仿真分析。仿真实验表明，基于发酵微生物的不同温度生长变化曲线仿真分析能够有效地提高微生物检测底用料的利用率及温度变化检测的准确性。为微生物发酵的检测研究提供参考。%Along with the high- speed development of China's microbial fermentation technology, microbial fermentation process under different temperature and microorganisms in the biological reaction, more and more get the attention of the researchers. For this, put forward the different temperature growth curve of microbial fermentation simulation analysis, based on the fermentation conditions of carbohydrates and the growth of filamentous fungi fermentation environment. Simulation results show that the different temperature growth curve of microbial fermentation simulation analysis can effectively improve the utilization rate of microbial detection base materials and the change of temperature detection accuracy.
Directory of Open Access Journals (Sweden)
Mariza Marie Fujita
1999-12-01
Full Text Available Objetivo: determinar curvas e tabelas de crescimento do diâmetro biparietal médio e da circunferência cefálica média em relação à idade gestacional de gestações gemelares e analisar eventuais diferenças com as existentes para fetos únicos e gêmeos. Métodos: por meio de exames ultra-sonográficos realizados a cada duas ou três semanas por um único observador em 34 pacientes com gestação gemelar sem patologias feto-maternas foi possível estabelecer curvas e tabelas do diâmetro biparietal médio e da circunferência cefálica média em relação a idade gestacional. Os valores destes parâmetros biométricos foram comparados aos descritos pela literatura para fetos únicos e gêmeos. Resultados: foram obtidas curvas e tabelas do diâmetro biparietal e da circunferência cefálica em relação a idade gestacional. O crescimento do diâmetro biparietal e da circunferência cefálica se revelou menor no terceiro trimestre em relação aos observados por Hadlock et al.15 para gestação única. A diferença entre os valores médios foi 6 mm (diâmetro biparietal e 2,0 cm (circunferência cefálica na 39ª semana de gestação. Foram observadas também algumas diferenças em relação a outros estudos de gestações gemelares. Conclusão: este estudo sugeriu que as curvas e tabelas de crescimento do diâmetro biparietal médio e da circunferência cefálica média de gestações únicas não são apropriadas para avaliação de gestações gemelares da população analisada principalmente no terceiro trimestre.Purpose: to estimate growth curves and tables of average biparietal diameter and average head circumference of twin gestations and to compare them with published growth curves for singletons and twins. Methods: growth curves and tables of average biparietal diameter and average head circumference were obtained from sonographic examinations of 34 patients with twin gestations without maternal and fetal complications. Sonographic
Nageshwari, M.; Jayaprakash, P.; Kumari, C. Rathika Thaya; Vinitha, G.; Caroline, M. Lydia
2017-04-01
An efficient nonlinear optical semiorganic material L-valinium L-valine chloride (LVVCl) was synthesized and grown-up by means of slow evaporation process. Single crystal XRD evince that LVVCl corresponds to monoclinic system having acentric space group P21. The diverse functional groups existing in LVVCl were discovered with FTIR spectral investigation. The UV-Visible and photoluminescence spectrum discloses the optical and electronic properties respectively for the grown crystal. Several optical properties specifically extinction coefficient, reflectance, linear refractive index, electrical and optical conductivity were also determined. The SEM analysis was also carried out and it portrayed the surface morphology of LVVCl. The calculated value of laser damage threshold was 2.59 GW/cm2. The mechanical and dielectric property of LVVCl was investigated employing microhardness and dielectric studies. The second and third order nonlinear optical characteristics of LVVCl was characterized utilizing Kurtz Perry and Z scan technique respectively clearly suggest its suitability in the domain of optics and photonics.
Institute of Scientific and Technical Information of China (English)
龙开胜; 陈利根
2011-01-01
The purpose of this paper is to explore whether a Kuznets curve relation exists between the economic growth and land law violations, which can serve as a reference for governing land law violations. The methods of theoretical analysis and econometrics are employed. The results show that the Kuznets curve relation between economic growth and land law violations is verified in theory, and the practical evidences are found at national level, also in the eastern region as well as the developed areas, i.e., the land law violations increase firstly and then reduce at an inflexion along with the economic growth. But the Kuznets curve relation is not significant in the central and western areas. The paper also finds that the appropriate Kuznets curve inflection point is 20000 RMB in terms of GDP per capita. Therefore, improving the quality of economic growth, transferring the pattern of economic development into environmental friendly one, reforming land management system, and strengthening the application of technology in monitoring land law violations are effective measures for governing land law violations.%研究目的：从理论和实证角度探讨经济增长与土地违法的库兹涅茨曲线效应关系，为土地违法治理提供科学依据。研究方法：理论分析，经济计量分析。研究结果：经济增长与土地违法之间的库兹涅茨曲线效应具有理论上的可能性，全国层面、东部地区以及经济较发达地区的经验也确实符合“土地违法随经济增长先增加后减少”的论断，但中两部地区及经济欠发达地区的库兹涅茨曲线效应不显著；人均GDP达到2万元是库兹涅茨曲线拐点出现的一个比较恰当的位置。研究结论：提高经济发展质量、转变经济发展方式、完善土地管理制度、强化技术手段在土地违法查处中的作用是加强土地违法治理的重要措施。
Kalaiyarasi, S.; Zahid, I. MD; Devi, S. Reena; Kumar, R. Mohan
2017-02-01
Organic nonlinear optical material Piperidinium 3-carboxy-4-hydroxy benzenesulfonate (PBS) single crystal was successfully grown by solution growth method. Single crystal X-ray diffraction study confirms that, the grown crystal belongs to P21/n space group. The crystalline quality of PBS was ascertained by HRXRD studies. Infrared spectral analysis showed the vibrational behaviour of chemical bonds and presence of its functional groups. TG/DTA studies were used to study the thermal stability and decomposition stages of the compound. UV-visible transmittance studies showed the transparency region, cut-off wavelength and band gap of the grown crystal. Photoluminescence emission study was carried out for the grown crystal to show its electronic properties. By using Nd:YAG laser, the laser damage threshold was estimated for the grown crystal. The third-order nonlinear optical parameters of the grown crystal were estimated by Z-scan technique using He-Ne laser source. The mechanical property of the PBS crystal was studied by using Vicker's microhardness measurement.
Institute of Scientific and Technical Information of China (English)
B.Milton Boaz; A.Leyo Rajesh; S. Xavier Jesu Raja; S. Jerome Das
2004-01-01
Sodium paranitrophenolate dihydrate (NPNa·2H2O) is an excellent semiorganic nonlinear optical (NLO) material, crystallizes both in water and methanol with high degree of transparency. Good optical quality single crystals of dimension upto 18 mmx6 mmx3 mm are obtained by isothermal solvent evaporation technique. The solubility of the crystal in different solvents was measured gravimetrically. The single crystals of NPNa·2H2O show variation in physical properties and growth rate in different solvents. Methanol or ethanol solution yields crystals of bipyramidal shape with clear morphology. However, methanol grown crystal is exhibiting improved hardness parameters and possesses excellent thermal stability as compared to water grown crystals. The effects of solvent on hardness parameter along with thermal and optical properties of NPNa·2H2O was revealed in this paper.
Directory of Open Access Journals (Sweden)
Claudia Cristina Paro de Paz
2004-08-01
Logistic nonlinear model that included the fixed effects of the contemporary group and genotype of the genes kappa-casein-HinfI (CSN3: AA and AB, growth hormone-AluI (GH: LL and LV, and beta-lactoglobulin-HaeIII (LGB: AA, AB and BB, to examine the effect of these markers on the growth curve. The Logistic model used to explain the growth of the CN, AN and SN genetic groups, was influenced by the genotypes of the CSN3, GH e LGB markers. The major differences started at 12-13 months of age. The value of the maturing rate (k of the AA genotype for CSN3 was superior in relation to AB genotype in the CN, AN and SN genetic groups. However, there was observed small difference in estimate of the asymptotic value (A for the AA and AB genotypes in CN and SN genetic groups. For the GH polymorphism there were inferior values of the parameters A and k to LL genotype in relation to LV genotype for the AN genetic group, however for the SN genetic group there was inferior value of the parameter A and superior value of the parameter k to LV genotype in relation to LL genotype. The same was observed for the LGB, there were superior values of the parameter k of the AA and AB genotypes in relation to the BB for the AN genetic group, however, there was inferior value of the parameter k of the AB genotype in relation to the BB, for the SN genetic group.
Pichan, Karuppasamy; Muthu, Senthil Pandian; Perumalsamy, Ramasamy
2017-09-01
The organic single crystal of piperazinium bis(4-hydroxybenzenesulphonate) (P4HBS) was grown by slow evaporation solution technique (SEST) at room temperature. The lattice parameters of the grown crystal were confirmed by single crystal X-ray diffraction analysis. Functional groups of P4HBS crystal were confirmed by FTIR spectrum analysis. The optical quality of the grown crystal was identified by the UV-Vis NIR spectrum analysis. The grown crystal has good optical transmittance in the range of 410-1100 nm. In photoluminescence spectrum, sharp emission peaks are observed, which indicates the ultraviolet (UV) emission. The photoconductivity study reveals that the grown crystal has negative photoconductive nature. The thermal behaviour of the P4HBS crystal was investigated by thermogravimetric and differential thermal analysis (TG-DTA). The mechanical stability of grown crystal was analyzed and the indentation size effect (ISE) was explained by Hays-Kendall's (HK) approach and proportional specimen resistance model (PSRM). Chemical etching study was carried out and the etch pit density (EPD) was calculated. The dielectric constant (ε‧) and dielectric loss (tan δ) as a function of frequency were measured for the grown crystal. The solid state parameters such as valence electron, plasma energy, Penn gap and Fermi energy were evaluated theoretically for the P4HBS using the empirical relation. The estimated values are used to calculate the electronic polarizability. The third-order nonlinear optical properties such as nonlinear refractive index (n2), absorption co-efficient (β) and susceptibility (χ(3)) were studied by Z-scan technique at 632.8 nm using He-Ne laser.
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.
Thirumurugan, Ramaiah; Anitha, Kandasamy
2017-05-01
In this work, a systematic study of an organic nonlinear optical (NLO) material, trans-4-hydroxy-l-proline (THP), C5H9NO3 is reported. An optical quality single crystals of THP have been successfully grown by using slow evaporation solution growth technique (SEST). The single crystal x-ray diffraction (SXRD) analysis reveals that grown crystal belongs to the orthorhombic system with non-centrosymmetric space group (NCS), P212121. Powder x-ray diffraction (PXRD) analysis shows relatively a good crystalline nature. The molecular structure of THP was recognized by NMR (1H and 13C) studies and its vibrational modes were confirmed by FTIR and FT-Raman vibrational studies. UV-Vis-NIR spectrum of grown crystal shows high optical transparency in the visible and near-IR region with low near-UV cut-off wavelength at 218 nm. Photoluminescence study confirms ultraviolet wavelength emission of THP crystal. The second harmonic generation (SHG) efficiency of grown crystal is 1.6 times greater with respect to standard potassium dihydrogen phosphate (KDP). Nonlinear refractive index (n 2) and nonlinear absorption coefficient (β) were determined using the Z-scan technique. The title compound owns high thermal stability of 294 °C and specific heat capacity (C P) of 1.21 J g-1 K-1 at 300 K and 11.33 J g-1 K-1 at 539 K (melting point). The laser-induced damage threshold (LDT) value of grown crystal was measured as 7.25 GW cm-2. The crystal growth mechanism and defects of grown crystal were studied by chemical etching technique. Mechanical strength was extensively studied by Vickers microhardness test and crystal void percentage analysis. Moreover, density functional theory (DFT) studies were carried out to probe the Mulliken charge distribution, frontier molecular orbitals (FMOs) and first order hyperpolarizability (β) of the optimized molecular structure to get a better insight of the molecular properties. These characterization results endorse that grown THP crystal as a
DEFF Research Database (Denmark)
Engelholm, S A; Spang-Thomsen, M; Vindeløv, L L
1986-01-01
Four human small cell carcinomas of the lung grown in nude mice were exposed to melphalan. Two of the tumors were derived from subpopulations isolated by in vitro cloning from the same tumor biopsy. The chemosensitivity of the tumors was determined by calculating the specific growth delay. Drug...
Prinzie, P.; Onghena, P.; Hellinckx, W.
2005-01-01
Cohort-sequential latent growth modeling was used to analyze longitudinal data for children's externalizing behavior from four overlapping age cohorts (4, 5, 6, and 7 years at first assessment) measured at three annual time points. The data included mother and father ratings on the Child Behavior Checklist and the Five-Factor Personality Inventory…
Prinzie, P.; Onghena, P.; Hellinckx, W.
2006-01-01
The aim of this study was to examine the normative developmental trajectories of aggressive and delinquent behavior in young children. Cohort-sequential univariate latent growth modeling (LGM) analyses were employed to conceptualize and analyze intraindividual changes in children's aggressive and delinquent behavior and interindividual differences…
Energy Technology Data Exchange (ETDEWEB)
Davis, C.G.
1990-01-01
The advent of nonlinear pulsation theory really coincides with the development of the large computers after the second world war. Christy and Stobbie were the first to make use of finite difference techniques on computers to model the bumps'' observed in the classical Cepheid light and velocity curves, the so-called Hertzsprung'' sequence. Following this work a more sophisticated analysis of the light and velocity curves from the models was made by Simon and Davis using Fourier techniques. Recently a simpler amplitude equation formalism has been developed that helps explain this resonance mechanism. The determination of Population I Cepheid masses by nonlinear methods will be discussed. For the lower mass objects, such as RR Lyrae and BL Her. stars, we find general agreement using evolutionary masses and nonlinear pulsation theory. An apparent difficulty of nonlinear pulsation theory occurs in the understanding of double'' mode pulsation, which will also be discussed. Recent studies in nonlinear pulsation theory have dealt with the question of mode selection, period doubling and the trends towards chaotic behavior such as is observed in the transition from W Virginis to RV Tauri-like stars. 10 refs., 1 fig., 2 tabs.
Frenkel, M. M.; LaVigne, M.; Miller, H. R.; Hill, T. M.; McNichol, A.; Gaylord, M. Lardie
2017-07-01
Bamboo corals, long-lived cold water gorgonin octocorals, offer unique paleoceanographic archives of the intermediate ocean. These Isididae corals are characterized by alternating gorgonin nodes and high Mg-calcite internodes, which synchronously extend radially. Bamboo coral calcite internodes have been utilized to obtain geochemical proxy data, however, growth rate uncertainty has made it difficult to construct precise chronologies for these corals. Previous studies have relied upon a single tie point from records of the anthropogenic Δ14C bomb spike preserved in the gorgonin nodes of live-collected corals to calculate a mean radial extension rate for the outer 50 years of skeletal growth. Bamboo coral chronologies are typically constructed by applying this mean extension rate to the entire coral record, assuming constant radial extension with coral age. In this study, we aim to test this underlying assumption by analyzing the organic nodes of six California margin bamboo corals at high enough resolution (coral collection date (2007.5) for four samples. Radial extension rates between tie points ranged from 10 to 204 μm/year, with a decrease in growth rate evident between the 1957-1970 and 1970-2007.5 periods for all four corals. A negative correlation between growth rate and coral radius (r =-0.7; p=0.04) was determined for multiple bamboo coral taxa and individuals from the California margin, demonstrating a decline in radial extension rate with specimen age and size. To provide a mechanistic basis for these observations, a simple mathematical model was developed based on the assumption of a constant increase in circular cross sectional area with time to quantify this decline in radial extension rate with coral size between chronological tie points. Applying the area-based model to our Δ14C bomb spike time series from individual corals improves chronology accuracy for all live-collected corals with complete Δ14C bomb spikes. Hence, this study provides
Institute of Scientific and Technical Information of China (English)
杨鸽; 李生彬; 袁栖; 管小乐
2012-01-01
The Economic growth of Gansu has increased the environmental pressure heavily. Based on the economic and environmental data from 1985 to 2009.GDP and typical environmental pollution index were selected,and a correlative model of measurement was established by using the statistical method. The results showed that under the environmental conditions and with present economic development of Gansu, there existed three forms of environmental Kuznets curve:inverted "U" curve,"U" curve and weak linear. According to the practial development of Gansu,the reasons of the curve were analyzed,and some suggestions for healthy and harmonious development between economy and environment were put forward .%随着甘肃省经济的增长,环境压力越来越大.基于1985～2009年经济和环境统计数据,选取人均GDP和典型环境污染指标,利用统计方法建立了二者相关性计量模型.结果表明:甘肃省的各类污染物与经济增长之间表现为3种曲线关系,呈现倒“U”型、“U”型、弱一元线性.并根据甘肃省经济发展实际,分析了环境库兹涅茨曲线,提出经济和环境协调健康发展的建议.
Experimental Simulation of Closed Timelike Curves
Ringbauer, Martin; Myers, Casey R; White, Andrew G; Ralph, Timothy C
2015-01-01
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 non-linearities and the emergence of causal structures in quantum mechanics-essential for any formulation of a quantum theory of gravity. Here we experimentally simulate the non-linear 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 t...
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.
Directory of Open Access Journals (Sweden)
Patricia Tholon
2009-10-01
diferentes, de acordo com a espécie, o sexo e o modelo utilizados na avaliação. Outra metodologia utilizada são os modelos de regressão aleatória, permitindo mudanças graduais nas covariâncias entre idades ao longo do tempo e predizendo variâncias e covariâncias em pontos contidos ao longo da trajetória estudada. A utilização de modelos de regressões aleatórias traz como vantagem a separação da variação da curva de crescimento fenotípica em seus diferentes efeitos genético aditivo e de ambiente permanente individual, mediante a determinação dos coeficientes de regressão aleatórios para esses diferentes efeitos. Além disto, não há necessidade de utilizar fatores de ajuste para a idade. Esta revisão teve por objetivos levantar os principais modelos matemáticos frequentistas utilizados no estudo de curvas de crescimento de aves, com maior ênfase nos empregados com a finalidade de estimar parâmetros genéticos e fenotípicos.The use of mathematical models to describe animal growth is not recent. They are able to summarize information on strategic dots of animal growth development and to describe the evolution of weight according to the animal age. It is also possible to compare different individuals in similar physiologic stages. The growth models most commonly used in poultry breeding are derived from Richards function, and they present parameters that provide biological interpretation and knowledge to select a specific shape of growth curve in poultry. However, it is also possible to use segmented polynomials to describe trend changes during the animal growth. One needs to consider important variables affecting the growth curve parameters estimates, such as, production system, specie, sex and their interactions. Model Goodness-of-fit can be based on many criteria such as coefficient of determination (R2, residual mean squared error, (LSe, estimated predicted mean error (PME, the easiness the analysis to reach convergence and the possibility of
Shanthi, A.; Krishnan, C.; Selvarajan, P.
2014-05-01
A novel organic nonlinear optical (NLO) material viz. N,N-dimethylurea picrate (NNDMP) was grown by the slow evaporation technique using N,N-dimethyl formamide as a solvent. The solubility of the grown sample has been estimated for various temperatures. The XRD study reveals that the grown crystal crystallizes in the monoclinic crystal system and the corresponding lattice parameters were determined. The relative second harmonic generation (SHG) efficiency of the NNDMP was found to be 1.045 times that of KDP by Kurtz-Perry powder technique. FTIR and FT-Raman spectral analyses explain the various functional groups present in the sample. The optical spectral analysis of the grown crystal has been performed by UV-vis-NIR spectroscopy and the band gap energy was found out. The thermogravimetric analysis and differential thermal analysis (TG/DTA) reveal that the NNDMP crystal is stable at up to 172 °C. A prominent first-order ferroelectric to paraelectric phase transition at 323 K has been observed and activation energy was determined for the AC conduction process in the sample.
Directory of Open Access Journals (Sweden)
Sharda J. Shitole
2015-12-01
Full Text Available Single crystals of calcium iodate, monohydrate [Ca (IO32, H2O] were grown by simple gel technique by single and double diffusion method. Morphologies and habit faces like prismatic, prismatic pyramidal, needle shaped, hopper crystals were obtained. Few crystals were opaque, some were translucent and some good quality transparent crystals were obtained. EDAX spectrum verified that crystals are of calcium iodate, monohydrate indeed and was used to find Atomic % and Weight %. Unit cell parameters were obtained from the X-ray diffractogram. The calculated unit cell parameters, β, and‘d’ values are in good agreement with reported ones. Structural analysis was done by using FTIR spectroscopy which confirmed the presence of fundamental infrared frequencies, generally observed in all iodate compounds. Thermal analysis exhibits three steps explicitly on heating the samples. The first step involves dehydration at 5500C, second step shows decomposition at 5800C, and the third step involves again decomposition at 6400C. Powder second harmonic generation experiments exhibit the nonlinear nature of the substance.
Tamilselvan, S.; Vimalan, M.; Vetha Potheher, I.; Rajasekar, S.; Jeyasekaran, R.; Antony Arockiaraj, M.; Madhavan, J.
2013-10-01
An efficient amino acid family nonlinear optical single crystal L-phenylalanine-benzoic acid (LPB) was conveniently grown by slow evaporation technique at room temperature. The crystal system and the lattice parameters were analyzed by single crystal X-ray diffraction studies. The grown crystal has excellent transmission in the entire visible region and its lower cut-off wavelength was found to be 248 nm. The SHG efficiency of the grown crystal was found to be 1.6 times higher than that of KDP crystal. The Laser damage threshold value of LPB has been found to be 6.5 GW/cm2. The sample was thermally stable up to 134 °C. Microhardness, dielectric and AC/DC conductivity measurements were made along (0 0 1) plane and reported for the first time. Microhardness studies revealed that the sample belongs to hard nature. Frequency dependent dielectric constant was measured for different temperatures and found maximum dielectric constant of 14 for 363 K. Photoconductivity studies of LPB divulged its negative photoconducting nature.
Directory of Open Access Journals (Sweden)
Julio César de Souza
2008-06-01
Full Text Available The present study had the objective to analyze the application of non-linear models to describe the growth of crossbred Santa Inês x Texel sheep and, then define the best adjusted model, to evaluate the influence of environmental factors (sex, birth month and type of parturition over curve parameters. Data based on 24 weights, 15 days each, of 75 animals from birth up to 365 days of age were used. The non-linear models evaluated were: Brody, Von Bertalanffy, Richards, Logistic and Gompertz. The models Von Bertalanffy and Gompertz presented the best adjustment at the initial growth period. However, the Logistic model provided the best adjustment from 120 days of age and the lowest genetic divergence in relation to the observed average weight and, therefore, it was considered the more appropriate growth model within the studied period. An accentuated decrease in the absolute growth rate was observed after weaning and nutritional strategies should be performed to avoid the low weight gain at this stage. Environmental factors had no effects on the Logistic curve parameters, excepting the parturition kind, which influenced the parameter m. The correlation estimated between the parameters A and k was negative (-0.44, indicating that fast-growing young animals are less likely to reach higher weights when adults.O objetivo deste estudo foi analisar modelos não lineares para descrever o crescimento em ovinos mestiços ½Santa Inês x ½Texel e, após a definição do modelo de melhor ajuste, avaliar a influência de fatores ambientais (sexo, mês de nascimento e tipo de parto sobre os parâmetros da curva. Foram utilizados dados de 24 pesagens (quinzenais de 75 animais do nascimento aos 365 dias de idade. Os modelos não lineares utilizados foram: Brody, Von Bertalanffy, Richards, Logístico e Gompertz. Os modelos Von Bertalanffy e Gompertz apresentaram o melhor ajuste na fase inicial de crescimento. O modelo Logístico apresentou melhor ajuste a
Westerhof, E.; de Blank, H. J.; Pratt, J.
2016-03-01
Two dimensional reduced MHD simulations of neoclassical tearing mode growth and suppression by ECCD are performed. The perturbation of the bootstrap current density and the EC drive current density perturbation are assumed to be functions of the perturbed flux surfaces. In the case of ECCD, this implies that the applied power is flux surface averaged to obtain the EC driven current density distribution. The results are consistent with predictions from the generalized Rutherford equation using common expressions for Δ \\text{bs}\\prime and Δ \\text{ECCD}\\prime . These expressions are commonly perceived to describe only the effect on the tearing mode growth of the helical component of the respective current perturbation acting through the modification of Ohm’s law. Our results show that they describe in addition the effect of the poloidally averaged current density perturbation which acts through modification of the tearing mode stability index. Except for modulated ECCD, the largest contribution to the mode growth comes from this poloidally averaged current density perturbation.
Han, Guopeng; Wang, Ying; Su, Xin; Yang, Zhihua; Pan, Shilie
2017-05-15
Mid-Infrared nonlinear optical (Mid-IR NLO) crystals with excellent performances play a particularly important role for applications in areas such as telecommunications, laser guidance, and explosives detection. However, the design and growth of high performance Mid-IR NLO crystals with large NLO efficiency and high laser-damage threshold (LDT) still face numerous fundamental challenge. In this study, two potential Mid-IR NLO materials, Rb2LiVO4 (RLVO) and Cs2LiVO4 (CLVO) with noncentrosymmetric structures (Orthorhombic, Cmc21) were synthesized by high-temperature solution method. Thermal analysis and powder X-ray diffraction demonstrate that RLVO and CLVO melt congruently. Centimeter sized crystals of CLVO have been grown by the top-seeded solution growth method. RLVO and CLVO exhibit strong second harmonic generation (SHG) effects (about 4 and 5 times that of KH2PO4, respectively) with a phase-matching behavior at 1.064 μm, and a wide transparency range (0.33-6.0 μm for CLVO). More importantly, RLVO and CLVO possess a high LDT value (~28 × AgGaS2). In addition, the density functional theory (DFT) and dipole moments studies indicate that the VO4 anionic groups have a dominant contribution to the SHG effects in RLVO and CLVO. These results suggest that the title compounds are promising NLO candidate crystals applied in the Mid-IR region.
There are four natural curves in the spinal column. The cervical, thoracic, lumbar, and sacral curvature. The curves, along with the intervertebral disks, help to absorb and distribute stresses that occur from everyday activities such as walking or from ...
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.
Parametrizing Algebraic Curves
Lemmermeyer, Franz
2011-01-01
We present the technique of parametrization of plane algebraic curves from a number theorist's point of view and present Kapferer's simple and beautiful (but little known) proof that nonsingular curves of degree > 2 cannot be parametrized by rational functions.
Suresh, M.; Bahadur, S. Asath; Athimoolam, S.
2016-05-01
A new organic hydrogen bonded material, L-valinium p-toluenesulfonate monohydrate (LVPT), was synthesized and grown as a single crystal by slow evaporation solution growth technique with the dimension of 29 × 7 × 4 mm3. A good X-ray quality single crystal was selected from the grown crop and used for single crystal diffraction study. It reveals that the compound crystallized in a non-centrosymmetric monoclinic space group P21 with two set of molecules in unit cell. The plane of the carboxyl group of the cation is making dihedral angle of 85.4(1)° with the plane of the aromatic ring of the anion. The crystal packing features intricate three dimensional hydrogen bonding network through chain and ring motifs. These hydrogen bonded motifs are observed at x = 0 or 1 and aromatic rings of the cations are stacked at x = 1/2 leading to alternate hydrophilic and hydrophobic layers, respectively, along a-axis of the unit cell. Fourier transform infrared (FTIR) and Raman (FT-Raman) spectral studies have been performed to identify the functional groups. The optical transmittance and the lower cutoff wavelength of the LVPT have been identified by UV-Vis absorption studies. Second harmonic generation test using a laser with wavelength of 1064 nm confirms the nonlinear optical efficiency of the sample as 1.5 greater than KDP. The thermal and mechanical properties of the sample were examined by TG/DTA and Vicker's microhardness tests, respectively. Further, the solid state properties were calculated and found to be better than the known nonlinear optical material KDP.
Lament, Claudia
2014-01-01
I wish to showcase the importance of plasticity of narrative in fantasy formations, as exemplified in Achilles' psychological trajectory in The Iliad. Applying conceptual formulations concerning the psychoanalytic developmental process to Achilles' growth piques my reflections about the sibling experience and its unique position in the mental life of children and adolescents. With developmental advance and the capacity for measured fluidity of self and other structures, the original sibling experience--whether it be tilted toward aggressiveness or toward loving concern or a place in between--may acquire new meanings. By locating it within this contextual framework, Achilles' story line can be seen as a metaphorical description of the continuous and discontinuous patterns in growth. This poses intriguing questions: What contexts are useful in pondering Achilles' psychological shifts? Might the domain of disposition prove useful? Is birth order another? Is his gradual empathic concern for the enemy a demonstration of an elasticity of imaginative capacity that reassembles murderous potential? Child and adult analysts alike may find a rich trove in Homer's masterpiece for contemplating potential sources within their patients that spur forward movement.
Institute of Scientific and Technical Information of China (English)
郭素芳; 魏瑞霞; 张勇; 福泉; 张军力
2013-01-01
Objective To characterize the growth curve of Brucella in Bact/Alert blood culture system which may be helpful to predict the growth of Brucella strain for earlier clinical diagnosis of brucellosis.Methods The epidemiological,clinical and labo-ratory data including growth curve of Brucella were reviewed and analyzed retrospectively for 15 cases of brucellosis as con-firmed by positive serological test and brucellosis agglutination test.Results All the 15 patients had irregular fever and history of animal exposure,even though their clinical feature and signs varied greatly.The growth curve of Brucella in blood culture showed the same chracteristics in the 15 patients,including:the time to positive alarm was about 72 hours,a longer lag phase, shorter logarithmic phase,a shorter vertical axis corresponding to the logarithmic phase,and a flat stable phase.Conclusions The clinical manifestation of brucellosis is variable and non-specific.Lack of awareness of this disease makes the clinicians mis-diagnose it easily.Therefore,blood culture is critical for clarifying the etiology in febrile patients.The growth curve of bacteria during blood culture is useful for early diagnosis of brucellosis and prevention of laboratory infections.%目的：观察布鲁菌在 Bact/Alert 血培养仪上生长曲线特点，帮助预测该菌株生长，协助临床快速诊断布鲁菌病。方法对血培养阳性，经血清学检测布鲁菌凝集试验阳性确诊的15例布鲁菌病患者的流行病学、临床资料、实验室资料进行回顾分析。结果15例患者均有不规则发热、动物接触史。15例患者的血培养细菌生长曲线具有相同的特点：阳性报警时间72 h 左右，迟缓期较长，生长期较短，生长期对应的纵轴较短，稳定期平缓。结论布鲁菌病临床表现多样，临床医师对该病的认识不足容易误诊，因此对发热患者应重视血液病原学检验。实验室工作人员通过观察血培养细菌
Energy Technology Data Exchange (ETDEWEB)
Balakrishnan, T., E-mail: balacrystalgrowth@gmail.com [Crystal Growth Laboratory, PG & Research Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023, Tamil Nadu (India); Sathiskumar, S. [Crystal Growth Laboratory, PG & Research Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023, Tamil Nadu (India); Ramamurthi, K. [Crystal Growth and Thin Film Laboratory, Department of Physics and Nanotechnology, SRM University, Kattankulathur, 603 203, Kancheepuram, Tamil Nadu (India); Thamotharan, S. [Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA University, Thanjavur, 613 401 (India)
2017-01-15
Single crystal of a novel metal organic nonlinear optical (NLO) cadmium (II) dibromide L - proline monohydrate (CBLPM) of size 7 × 7 × 5 mm{sup 3} was grown from slow evaporation technique. Single crystal X – ray diffraction analysis reveals that the crystal belongs to orthorhombic system with lattice parameters a = 10.1891 (8) Å, b = 13.4961 (11) Å, c = 7.4491 (5) Å and space group P2{sub 1}2{sub 1}2{sub 1}. The powder X – ray diffraction pattern of CBLPM was recorded and the X – ray diffraction peaks were indexed. The various functional groups of CBLPM were identified by the FT – IR and FT – Raman spectral analyses. The optical transmittance window and lower cut off wavelength of CBLPM were identified from UV – Vis – NIR studies. The mechanical strength of the grown crystal was estimated using Vickers microhardness test. Dielectric constant and dielectric loss measurements were carried out at different temperatures in the frequency range of 50 Hz - 2 MHz. The photoluminescence spectrum was recorded in the wavelength range 200–400 nm and the estimated optical band gap was ∼4.1 eV. Etching studies were carried out for different etching time. Thermal stability of CBLPM was determined using thermogravimetric analysis. Laser induced damage threshold study was carried out for the grown crystal using Nd:YAG laser. Size dependent second harmonic generation efficiency of the grown crystal was determined by Kurtz and Perry powder technique with different particle size using Nd:YAG laser with wavelength 1064 nm. Second harmonic generation efficiency of the powdered CBLPM crystal was ∼2.3 times that of potassium dihydrogen orthophosphate. - Highlights: • CBLPM crystal belongs to orthorhombic crystal system with space group P2{sub 1}2{sub 1}2{sub 1.} • Transmittance of CBLPM is ∼80% in the 650–1100 nm range. • Powder SHG efficiency of CBLPM increases with increase in particle size. • SHG efficiency of 0.57 μm size powdered CBLPM is ∼2