scholarly journals Growth of alveoli during postnatal development in humans based on stereological estimation

2014 ◽  
Vol 307 (4) ◽  
pp. L338-L344 ◽  
Author(s):  
Matt J. Herring ◽  
Lei F. Putney ◽  
Gregory Wyatt ◽  
Walter E. Finkbeiner ◽  
Dallas M. Hyde
Keyword(s):  
Growth Curve ◽  
Nonhuman Primates ◽  
Human Lung ◽  
Growth Curves ◽  
Human Growth ◽  
Prenatal Development ◽  
Laboratory Model ◽  
Prenatal Growth ◽  
Radial Alveolar Count ◽  
Reduced Rate

Alveolarization in humans and nonhuman primates begins during prenatal development. Advances in stereological counting techniques allow accurate assessment of alveolar number; however, these techniques have not been applied to the developing human lung. Based on the recent American Thoracic Society guidelines for stereology, lungs from human autopsies, ages 2 mo to 15 yr, were fractionated and isometric uniform randomly sampled to count the number of alveoli. The number of alveoli was compared with age, weight, and height as well as growth between right and left lungs. The number of alveoli in the human lung increased exponentially during the first 2 yr of life but continued to increase albeit at a reduced rate through adolescence. Alveolar numbers also correlated with the indirect radial alveolar count technique. Growth curves for human alveolarization were compared using historical data of nonhuman primates and rats. The alveolar growth rate in nonhuman primates was nearly identical to the human growth curve. Rats were significantly different, showing a more pronounced exponential growth during the first 20 days of life. This evidence indicates that the human lung may be more plastic than originally thought, with alveolarization occurring well into adolescence. The first 20 days of life in rats implies a growth curve that may relate more to prenatal growth in humans. The data suggest that nonhuman primates are a better laboratory model for studies of human postnatal lung growth than rats.

scholarly journals A Hybrid Modeling Technique of Epidemic Outbreaks with Application to COVID-19 Dynamics in West Africa

Biology ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 365
Author(s):  
Chénangnon Frédéric Tovissodé ◽  
Jonas Têlé Doumatè ◽  
Romain Glèlè Kakaï
Keyword(s):  
West Africa ◽  
Growth Curve ◽  
Exponential Growth ◽  
Latency Period ◽  
Growth Curves ◽  
Exponential Growth Phase ◽  
Model Framework ◽  
Logistic Regression Models ◽  
Containment Measures ◽  
Reporting Data

The widely used logistic model for epidemic case reporting data may be either restrictive or unrealistic in presence of containment measures when implemented after an epidemic outbreak. For flexibility in epidemic case reporting data modeling, we combined an exponential growth curve for the early epidemic phase with a flexible growth curve to account for the potential change in growth pattern after implementation of containment measures. We also fitted logistic regression models to recoveries and deaths from the confirmed positive cases. In addition, the growth curves were integrated into a SIQR (Susceptible, Infective, Quarantined, Recovered) model framework to provide an overview on the modeled epidemic wave. We focused on the estimation of: (1) the delay between the appearance of the first infectious case in the population and the outbreak (“epidemic latency period”); (2) the duration of the exponential growth phase; (3) the basic and the time-varying reproduction numbers; and (4) the peaks (time and size) in confirmed positive cases, active cases and new infections. The application of this approach to COVID-19 data from West Africa allowed discussion on the effectiveness of some containment measures implemented across the region.

scholarly journals Growth in achondroplasia, from birth to adulthood, analysed by the JPA-2 model

2020 ◽  
Vol 33 (12) ◽  
pp. 1589-1595
Author(s):  
Mariana del Pino ◽  
Virginia Fano ◽  
Paula Adamo
Keyword(s):  
General Population ◽  
Growth Curve ◽  
Growth Velocity ◽  
Adult Height ◽  
Growth Curves ◽  
Peak Height ◽  
Height Growth ◽  
Individual Growth ◽  
Height Velocity ◽  
Peak Height Velocity

AbstractObjectivesIn general population, there are three phases in the human growth curve: infancy, childhood and puberty, with different main factors involved in their regulation and mathematical models to fit them. Achondroplasia children experience a fast decreasing growth during infancy and an “adolescent growth spurt”; however, there are no longitudinal studies that cover the analysis of the whole post-natal growth. Here we analyse the whole growth curve from infancy to adulthood applying the JPA-2 mathematical model.MethodsTwenty-seven patients, 17 girls and 10 boys with achondroplasia, who reached adult size, were included. Height growth data was collected from birth until adulthood. Individual growth curves were estimated by fitting the JPA-2 model to each individual’s height for age data.ResultsHeight growth velocity curves show that after a period of fast decreasing growth velocity since birth, with a mean of 9.7 cm/year at 1 year old, the growth velocity is stable in late preschool years, with a mean of 4.2 cm/year. In boys, age and peak height velocity in puberty were 13.75 years and 5.08 cm/year and reach a mean adult height of 130.52 cm. In girls, the age and peak height velocity in puberty were 11.1 years and 4.32 cm/year and reach a mean adult height of 119.2 cm.ConclusionsThe study of individual growth curves in achondroplasia children by the JPA-2 model shows the three periods, infancy, childhood and puberty, with a similar shape but lesser in magnitude than general population.

scholarly journals Growth curve of Atlantoscia floridana (van Name) (Crustacea, Isopoda, Philosciidae) from a Brazilian Restinga Forest

2004 ◽  
Vol 21 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Paula Beatriz Araujo ◽  
Georgina Bond-Buckup
Keyword(s):  
Growth Rate ◽  
Growth Curve ◽  
Urban Areas ◽  
Field Data ◽  
Growth Curves ◽  
Rio Grande ◽  
Rio Grande Do Sul ◽  
Differential Growth ◽  
Estimate Life Expectancy ◽  
Males And Females

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.

Factors governing the shape of the growth curve of body weight and the age at slaughter of Suffolk × Welsh lambs

1966 ◽  
Vol 8 (3) ◽  
pp. 435-444 ◽  
Author(s):  
J. S. Broadbent ◽  
J. H. Watson
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Growth Curve ◽  
Compensatory Growth ◽  
Marked Effect ◽  
Growth Curves ◽  
Live Weight ◽  
Linear Component ◽  
Slaughter Weight ◽  
Birth Type

Curves of growth in live-weight, from birth to 16 weeks of age, of 362 Suffolk × Welsh lambs were analysed for the effect of sex, birth type, sire and test centre environment and related to variation in age at slaughter.The relative pre-natal disadvantages of twin lambs resulted in their curves of growth differing from those of single-born animals, particularly in males. Test centre environment exerted a marked effect in such cases. At one centre, male twins showed marked compensatory growth.Differences in growth existed between the 14 sire progeny groups. As the linear component of the growth curves decreased, the quadratic values became increasingly negative. Deceleration of growth was most marked in slowest growing progeny groups and this was accentuated by a poor test centre environment.These factors combined to influence age at slaughter, which was also related to birth weight of the lamb. Lambs at the best test centre reached slaughter weight 10 and 16 days earlier than lambs at the two remaining centres. Sires produced differences in age at slaughter of 10 to 14 days, within centres.

scholarly journals Hypothesized, Directly-Coded Curve Shapes in Growth Curve Analysis: An Example

2013 ◽  
Vol 3 (2) ◽  
pp. 13 ◽  
Author(s):  
Patricia M. Herman ◽  
Lee Sechrest
Keyword(s):  
Hierarchical Linear Modeling ◽  
Growth Curve ◽  
Degrees Of Freedom ◽  
Growth Curves ◽  
Curve Analysis ◽  
Small Samples ◽  
Growth Curve Analysis ◽  
Linear Modeling ◽  
Individual Level ◽  
The Individual

Growth curve analysis provides important informational benefits regarding intervention outcomes over time. Rarely, however, should outcome trajectories be assumed to be linear. Instead, both the shape and the slope of the growth curve can be estimated. Non-linear growth curves are usually modeled by including either higher-order time variables or orthogonal polynomial contrast codes. Each has limitations (multicollinearity with the first, a lack of coefficient interpretability with the second, and a loss of degrees of freedom with both) and neither encourages direct testing of alternative hypothesized curve shapes. Especially in studies with relatively small samples it is likely to be useful to preserve as much information as possible at the individual level. This article presents a step-by-step example of the use and testing of hypothesized curve shapes in the estimation of growth curves using hierarchical linear modeling for a small intervention study. DOI:10.2458/azu_jmmss_v3i2_herman

scholarly journals Growth Curve of Selectively Bred Tambaqui (Colossoma macropomum) Reared in Different Environments

2020 ◽  
Vol 8 (3) ◽  
pp. 585
Author(s):  
Rebeca Marcos ◽  
Ruy Alberto Caetano Corrêa Filho ◽  
Janessa Sampaio de Abreu ◽  
Guilherme Do Nascimento Seraphim ◽  
Ana Carla Carvalho Silva ◽  
...  
Keyword(s):  
Growth Curve ◽  
Growth Curves ◽  
Growth Patterns ◽  
Production Performance ◽  
Environment Interaction ◽  
Morphometric Traits ◽  
Mato Grosso ◽  
Colossoma Macropomum ◽  
Genotype Environment Interaction ◽  
The Family

The objective of this study was to obtain the growth curve of selectively bred tambaqui (Colossoma macropomum) reared in different environments. The experiment was carried out in the municipalities of Santo Antônio de Leverger (Mato Grosso – MT) and Campo Grande (Mato Grosso do Sul – MS), Brazil, over 431 days. Weight and morphometric traits of two families (A and B) from the second generation of selective breeding (G2) were measured every 30-45 days. The Gompertz regression model was used to obtain the growth curves. The production performance of both families and the interaction between families and locations (genotype × environment) were evaluated by analysis of variance considering the family (A and B), location (MT and MS), family × location interaction and error as variation factors. The asymptotic value (parameter A) obtained for weight and morphometric traits (except head length) was higher (P<0.05) in MT (weight of families A and B: 2279.6 g) than in MS (weight of family A: 1400.0 g; weight of family B: 1600.0 g). Family B showed better production performance in MS. There was a genotype × environment interaction effect on weight, body length and standard length. The two families have distinct growth patterns in different production environments. Family B has better growth performance in the environment with lower temperatures (MS).

Comparative Study Of The Growth Curves Of B. subtilis, K. pneumoniae, C. xerosis And E. coli Bacteria In Medium Containing Nanometric Silicon Particles

2002 ◽  
Vol 737 ◽  
Author(s):  
Lilyanna Pérez ◽  
Marjorie Flores ◽  
J. Avalos ◽  
L. San Miguel ◽  
O. Resto ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Growth Curve ◽  
Silicon Nanoparticles ◽  
Silicon Film ◽  
Growth Curves ◽  
Bacterial Strains ◽  
E Coli ◽  
Standard Curve ◽  
Nanometric Particles ◽  
Silicon Particles

ABSTRACTIn this research nanometric particles from luminescent (625nm) porous silicon film were synthesized. This particles were later inoculated in bacterial strains of B. subtilis (BSi) and K. pneumoniae (KSi). A comparison of the behavior of their growth curve and the ones reported for C. xerosis (XSi) and E. coli (ESi) in presence of silicon nanoparticles is presented. The growth curve of BSi, as well as the KSi, present changes compared to their standard curves. The BSi growth curve grows below the standard curve after the fifth hour, while in the KSi this happens after the eighth hour. Based on our preliminary findings we can speculate that at this point in time a critical population is present, and this may give rise to the possible incorporation of the silicon particles by the bacteria, or a possible pleomorphism inhibits reproduction. The stationary region, in both cases, takes place sooner than in the standard curve. No significant oscillations are observed in any case, which differs form the XSi curve, were oscillations of intervals of almost 1 hour were reported. In addition, these curves have a different behavior when compared to the ESi growth curve, in which no significant differences between the standard and the particle containing sample were reported.

Prognosis of Aphasia by Fitting Growth Curves

1989 ◽  
Vol 68 (3_suppl) ◽  
pp. 1147-1150
Author(s):  
Kyoichiro Yamada
Keyword(s):  
Growth Curve ◽  
Inflection Point ◽  
Growth Curves ◽  
Saturation Level ◽  
Logistic Curve ◽  
Exponential Curve ◽  
Gompertz Curve ◽  
Language Tests ◽  
The Difference

The recovery of word-emission ability by Japanese aphasics was examined quantitatively. The scores on a word-emission task were obtained in a series of language tests for aphasia. 17 aphasics were asked to utter names of animals, giving as many as possible within a minute. The task was repeated four times at intervals of 104.1 days on the average, ranging from 27 to 271 days. The score on the word-emission task was estimated by fitting a growth curve to scores on the former three tests. Modified exponential, logistic, and Gompertz curves were used for estimation. All estimated scores by three growth curves were larger than the observed scores. The modified exponential curve which does not have an inflection point produced the most remarkable error. Between two curves which have an inflection point the logistic curve produced less error than the Gompertz curve. The difference in error of estimation was due to the difference in the saturation level of the two curves.

Ultrasonographic characterisation of prenatal development in European brown hares (Lepus europaeus PALLAS, 1778): an evolutionary approach

2010 ◽  
Vol 22 (2) ◽  
pp. 448 ◽  
Author(s):  
Kathleen Roellig ◽  
Frank Goeritz ◽  
Thomas B. Hildebrandt
Keyword(s):  
Reproductive Tract ◽  
Growth Models ◽  
Prenatal Development ◽  
Heart Beat ◽  
Lepus Europaeus ◽  
European Rabbit ◽  
Corpora Lutea ◽  
European Brown Hare ◽  
Prenatal Growth ◽  
Evolutionary Characteristic

The European brown hare is one species in which reproduction appears to be particularly complex. Therefore, we studied the reproductive tract and prenatal development using high-resolution ultrasound of 159 pregnancies in 45 captive female hares. Consecutive examination of live hares was particularly useful in evaluating the very early stages of gestation. As such, it was possible to detect corpora lutea by Day 3 and embryonic vesicles, representing the earliest uterine embryonic stages, by Day 6. On Day 11, the heart beat of the embryo was detectable for the first time. We defined ultrasonographic milestones that were characteristic of the different stages of pregnancy. We also calculated growth models using eight different morphological parameters, including development of the corpus luteum. On the basis of these results, it is now possible to estimate the gestational age of a pregnant doe without knowing the date of conception. In contrast with the European rabbit, a distant relative, European hares give birth to precocial young. A comparison of the prenatal growth rate of both species suggests that the precocial state of the hare neonate is a more recently derived evolutionary characteristic, whereas the altricial condition of rabbits represents the ancestral mode.

scholarly journals Comparison of growth curves of two genotypes of dairy goats using nonlinear mixed models

2013 ◽  
Vol 152 (5) ◽  
pp. 829-842 ◽  
Author(s):  
J. G. L. REGADAS FILHO ◽  
L. O. TEDESCHI ◽  
M. T. RODRIGUES ◽  
L. F. BRITO ◽  
T. S. OLIVEIRA
Keyword(s):  
Random Effects ◽  
Growth Curve ◽  
Mixed Model ◽  
Growth Curves ◽  
Growth Patterns ◽  
Dairy Goat ◽  
Residual Variance ◽  
Nonlinear Mixed Model ◽  
Error Structure ◽  
Mixed Model Methodology

SUMMARYThe objective of the current study was to assess the use of nonlinear mixed model methodology to fit the growth curves (weightv.time) of two dairy goat genotypes (Alpine, +A and Saanen, +S). The nonlinear functions evaluated included Brody, Von Bertalanffy, Richards, Logistic and Gompertz. The growth curve adjustment was performed using two steps. First, random effectsu1,u2andu3were linked to the asymptotic body weight (β1), constant of integration (β2) and rate constant of growth (β3) parameters, respectively. In addition to a traditional fixed-effects model, four combinations of models were evaluated using random variables: all parameters associated with random effects (u1,u2andu3), onlyβ1andβ2(u1andu2), onlyβ1andβ3(u1andu3) and onlyβ1(u1). Second, the fit of the best adjusted model was refined by using the power variance and modelling the error structure. Residual variance ($\sigma _e^2 $) and the Akaike information criterion were used to evaluate the models. After the best fitting model was chosen, the genotype curve parameters were compared. The residual variance was reduced in all scenarios for which random effects were considered. The Richards (u1andu3) function had the best fit to the data. This model was reparameterized using two isotropic error structures for unequally spaced data, and the structure known in the literature as SP(MATERN) proved to be a better fit. The growth curve parameters differed between the two genotypes, with the exception of the constant that determines the proportion of the final size at which the inflection point occurs (β4). The nonlinear mixed model methodology is an efficient tool for evaluating growth curve features, and it is advisable to assign biologically significant parameters with random effects. Moreover, evaluating error structure modelling is recommended to account for possible correlated errors that may be present even when using random effects. Different Richard growth curve parameters should be used for the predominantly Alpine and Saanen genotypes because there are differences in their growth patterns.

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