Intercellular signaling pathways active during intervertebral disc growth, differentiation, and aging.

PubMed

Dahia, Chitra Lekha; Mahoney, Eric J; Durrani, Atiq A; Wylie, Christopher

2009-03-01

Intervertebral discs at different postnatal ages were assessed for active intercellular signaling pathways. To generate a spatial and temporal map of the signaling pathways active in the postnatal intervertebral disc (IVD). The postnatal IVD is a complex structure, consisting of 3 histologically distinct components, the nucleus pulposus, fibrous anulus fibrosus, and endplate. These differentiate and grow during the first 9 weeks of age in the mouse. Identification of the major signaling pathways active during and after the growth and differentiation period will allow functional analysis using mouse genetics and identify targets for therapy for individual components of the disc. Antibodies specific for individual cell signaling pathways were used on cryostat sections of IVD at different postnatal ages to identify which components of the IVD were responding to major classes of intercellular signal, including sonic hedgehog, Wnt, TGFbeta, FGF, and BMPs. We present a spatial/temporal map of these signaling pathways during growth, differentiation, and aging of the disc. During growth and differentiation of the disc, its different components respond at different times to different intercellular signaling ligands. Most of these are dramatically downregulated at the end of disc growth.

[Pubertal growth of 1,453 healthy children according to age at pubertal growth spurt onset. The Barcelona longitudinal growth study].

PubMed

Carrascosa, Antonio; Yeste, Diego; Moreno-Galdó, Antonio; Gussinyé, Miquel; Ferrández, Ángel; Clemente, María; Fernández-Cancio, Mónica

2018-02-20

Pubertal growth pattern differs according to age at pubertal growth spurt onset which occurs over a five years period (girls: 8-13 years, boys: 10-15 years). The need for more than one pubertal reference pattern has been proposed. We aimed to obtain five 1-year-age-interval pubertal patterns. Longitudinal (6 years of age-adult height) growth study of 1,453 healthy children to evaluate height-for-age, growth velocity-for-age and weight-for-age values. According to age at pubertal growth spurt onset girls were considered: very-early matures (8-9 years, n=119), early matures (9-10 years, n=157), intermediate matures (10-11 years, n=238), late matures (11-12 years, n=127) and very-late matures (12-13 years, n=102), and boys: very-early matures (10-11 years, n=110), early matures (11-12 years, n=139), intermediate matures (12-13 years, n=225), late matures (13-14 years, n=133) and very-late matures (14-15 years, n=103). Age at menarche and growth up to adult height were recorded. In both sexes, statistically-significant (P<.0001) and clinically-pertinent differences in pubertal growth pattern (mean height-for-age, mean growth velocity-for-age and mean pubertal height gain, values) were found among the five pubertal maturity groups and between each group and the whole population, despite similar adult height values. The same occurred for age at menarche and growth from menarche to adult height (P<.05). In both sexes, pubertal growth spurt onset is a critical milestone determining pubertal growth and sexual development. The contribution of our data to better clinical evaluation of growth according to the pubertal maturity tempo of each child will obviate the mistakes made when only one pubertal growth reference is used. Copyright © 2018. Publicado por Elsevier España, S.L.U.

Age, growth rates, and paleoclimate studies of deep sea corals

USGS Publications Warehouse

Prouty, Nancy G; Roark, E. Brendan; Andrews, Allen; Robinson, Laura; Hill, Tessa; Sherwood, Owen; Williams, Branwen; Guilderson, Thomas P.; Fallon, Stewart

2015-01-01

Deep-water corals are some of the slowest growing, longest-lived skeletal accreting marine organisms. These habitat-forming species support diverse faunal assemblages that include commercially and ecologically important organisms. Therefore, effective management and conservation strategies for deep-sea corals can be informed by precise and accurate age, growth rate, and lifespan characteristics for proper assessment of vulnerability and recovery from perturbations. This is especially true for the small number of commercially valuable, and potentially endangered, species that are part of the black and precious coral fisheries (Tsounis et al. 2010). In addition to evaluating time scales of recovery from disturbance or exploitation, accurate age and growth estimates are essential for understanding the life history and ecology of these habitat-forming corals. Given that longevity is a key factor for population maintenance and fishery sustainability, partly due to limited and complex genetic flow among coral populations separated by great distances, accurate age structure for these deep-sea coral communities is essential for proper, long-term resource management.

A new approach for the analysis of facial growth and age estimation: Iris ratio

PubMed Central

Machado, Carlos Eduardo Palhares; Flores, Marta Regina Pinheiro; Lima, Laíse Nascimento Correia; Tinoco, Rachel Lima Ribeiro; Bezerra, Ana Cristina Barreto; Evison, Martin Paul; Guimarães, Marco Aurélio

2017-01-01

The study of facial growth is explored in many fields of science, including anatomy, genetics, and forensics. In the field of forensics, it acts as a valuable tool for combating child pornography. The present research proposes a new method, based on relative measurements and fixed references of the human face—specifically considering measurements of the diameter of the iris (iris ratio)—for the analysis of facial growth in association with age in children and sub-adults. The experimental sample consisted of digital photographs of 1000 Brazilian subjects, aged between 6 and 22 years, distributed equally by sex and divided into five specific age groups (6, 10, 14, 18, and 22 year olds ± one month). The software package SAFF-2D® (Forensic Facial Analysis System, Brazilian Federal Police, Brazil) was used for positioning 11 landmarks on the images. Ten measurements were calculated and used as fixed references to evaluate the growth of the other measurements for each age group, as well the accumulated growth (6–22 years old). The Intraclass Correlation Coefficient (ICC) was applied for the evaluation of intra-examiner and inter-examiner reliability within a specific set of images. Pearson’s Correlation Coefficient was used to assess the association between each measurement taken and the respective age groups. ANOVA and Post-hoc Tukey tests were used to search for statistical differences between the age groups. The outcomes indicated that facial structures grow with different timing in children and adolescents. Moreover, the growth allometry expressed in this study may be used to understand what structures have more or less proportional variation in function for the age ranges studied. The diameter of the iris was found to be the most stable measurement compared to the others and represented the best cephalometric measurement as a fixed reference for facial growth ratios (or indices). The method described shows promising potential for forensic applications

A new approach for the analysis of facial growth and age estimation: Iris ratio.

PubMed

Machado, Carlos Eduardo Palhares; Flores, Marta Regina Pinheiro; Lima, Laíse Nascimento Correia; Tinoco, Rachel Lima Ribeiro; Franco, Ademir; Bezerra, Ana Cristina Barreto; Evison, Martin Paul; Guimarães, Marco Aurélio

2017-01-01

The study of facial growth is explored in many fields of science, including anatomy, genetics, and forensics. In the field of forensics, it acts as a valuable tool for combating child pornography. The present research proposes a new method, based on relative measurements and fixed references of the human face-specifically considering measurements of the diameter of the iris (iris ratio)-for the analysis of facial growth in association with age in children and sub-adults. The experimental sample consisted of digital photographs of 1000 Brazilian subjects, aged between 6 and 22 years, distributed equally by sex and divided into five specific age groups (6, 10, 14, 18, and 22 year olds ± one month). The software package SAFF-2D® (Forensic Facial Analysis System, Brazilian Federal Police, Brazil) was used for positioning 11 landmarks on the images. Ten measurements were calculated and used as fixed references to evaluate the growth of the other measurements for each age group, as well the accumulated growth (6-22 years old). The Intraclass Correlation Coefficient (ICC) was applied for the evaluation of intra-examiner and inter-examiner reliability within a specific set of images. Pearson's Correlation Coefficient was used to assess the association between each measurement taken and the respective age groups. ANOVA and Post-hoc Tukey tests were used to search for statistical differences between the age groups. The outcomes indicated that facial structures grow with different timing in children and adolescents. Moreover, the growth allometry expressed in this study may be used to understand what structures have more or less proportional variation in function for the age ranges studied. The diameter of the iris was found to be the most stable measurement compared to the others and represented the best cephalometric measurement as a fixed reference for facial growth ratios (or indices). The method described shows promising potential for forensic applications, especially

Growth factors, nutrient signaling, and cardiovascular aging.

PubMed

Fontana, Luigi; Vinciguerra, Manlio; Longo, Valter D

2012-04-13

Growth factors regulated by specific macronutrients have been shown to promote aging and accelerate mortality in the majority of the organisms studied. In particular, the enzymes activated by growth hormone, insulin, and insulin-like growth factor-1 in mammals and their orthologs in simple model organisms represent perhaps the best-understood proteins involved in the aging process. Dietary restriction, which reduces the level of insulin-like growth factor-1 and of other growth factors, has been associated with protection from diabetes, cancer, and cardiovascular diseases, and deficiencies in growth hormone signaling and insulin-like growth factor-1 are strongly associated with protection from cancer and diabetes in both mice and humans; however, their role in cardiac function and cardiovascular diseases is controversial. Here, we review the link between growth factors, cardiac function, and heart disease with focus on the cardioprotective and sensitizing effect of growth factors in both model organisms and humans.

Diameter growth of trees in an uneven-aged oak forest in the Missouri Ozarks

Treesearch

Edward F. Loewenstein; Paul S. Johnson; Harold E. Garrett

1997-01-01

We tested the efficacy of even-aged stand tables for predicting diameter growth of trees in uneven-aged oak stands. The study was based on the age- and diameter-structure of the Pioneer Forest, a 156,000-acre, privately owned oak forest in the Ozark Highlands of Missouri. The forest has been managed by single-tree selection since 1954.

Effects of a growth check on daily age estimates of age-0 alligator gar

USGS Publications Warehouse

Snow, Richard A.; Long, James M.

2016-01-01

Accurate age and growth information is essential for a complete knowledge of life history, growth rates, age at sexual maturity, and average life span in fishes. Alligator gar are becoming increasingly managed throughout their range and because this species spawns in backwater flooded areas, their offspring are prone to stranding in areas with limited prey, potentially affecting their growth. Because fish growth is tightly linked with otolith growth and annulus formation, the ability to discern marks not indicative of annuli (age checks) in alligator gar would give managers some insight when estimating ages. Previous studies have suggested that checks are often present prior to the first annulus in otoliths of alligator gar, affecting age estimates. We investigated check formation in otoliths of alligator gar in relation to growth and food availability. Sixteen age-0 alligator gar were marked with oxytetracycline (OTC) to give a reference point and divided equitably into two groups: a control group with abundant prey and an experimental group with limited prey. The experimental group was given 2 g of food per week for 20 days and then given the same prey availability as the control group for the next 20 days. After 40 days, the gar were measured, sacrificed, and their sagittae removed to determine if checks were present. Checks were visible on 14 of the 16 otoliths in the experimental group, associated with low growth during the first 20 days when prey was limited and accelerated growth after prey availability was increased. No checks were observed on otoliths of the control group, where growth and prey availability were consistent. Age estimates of fish in the control group were more accurate than those in the experimental group, showing that fish growth as a function of prey availability likely induced the checks by compressing daily ring formation.

Stand structure in eastside old-growth ponderosa pine forests of Oregon and northern California.

Treesearch

Andrew Youngblood; Timothy Max; Kent Coe

2004-01-01

Quantitative metrics of horizontal and vertical structural attributes in eastside old-growth ponderosa pine (Pinus ponderosa P. and C. Lawson var. ponderosa) forests were measured to guide the design of restoration prescriptions. The age, size structure, and the spatial patterns were investigated in old-growth ponderosa pine forests at three...

Accounting for Age Uncertainty in Growth Modeling, the Case Study of Yellowfin Tuna (Thunnus albacares) of the Indian Ocean

PubMed Central

Dortel, Emmanuelle; Massiot-Granier, Félix; Rivot, Etienne; Million, Julien; Hallier, Jean-Pierre; Morize, Eric; Munaron, Jean-Marie; Bousquet, Nicolas; Chassot, Emmanuel

2013-01-01

Age estimates, typically determined by counting periodic growth increments in calcified structures of vertebrates, are the basis of population dynamics models used for managing exploited or threatened species. In fisheries research, the use of otolith growth rings as an indicator of fish age has increased considerably in recent decades. However, otolith readings include various sources of uncertainty. Current ageing methods, which converts an average count of rings into age, only provide periodic age estimates in which the range of uncertainty is fully ignored. In this study, we describe a hierarchical model for estimating individual ages from repeated otolith readings. The model was developed within a Bayesian framework to explicitly represent the sources of uncertainty associated with age estimation, to allow for individual variations and to include knowledge on parameters from expertise. The performance of the proposed model was examined through simulations, and then it was coupled to a two-stanza somatic growth model to evaluate the impact of the age estimation method on the age composition of commercial fisheries catches. We illustrate our approach using the saggital otoliths of yellowfin tuna of the Indian Ocean collected through large-scale mark-recapture experiments. The simulation performance suggested that the ageing error model was able to estimate the ageing biases and provide accurate age estimates, regardless of the age of the fish. Coupled with the growth model, this approach appeared suitable for modeling the growth of Indian Ocean yellowfin and is consistent with findings of previous studies. The simulations showed that the choice of the ageing method can strongly affect growth estimates with subsequent implications for age-structured data used as inputs for population models. Finally, our modeling approach revealed particularly useful to reflect uncertainty around age estimates into the process of growth estimation and it can be applied to any

[Analysis and design structure of an aging society].

PubMed

Fujimasa, Iwao

2012-01-01

On observing present Japanese society, we can find deep gaps between the present system and its probable future. One of the gaps may be due to the misconception that future societal make up is not definite. The aim of the current study was to investigate a future societal structure and to develop methods of adding a timed dimension policy to the societal structure. This is named "A theory of structuralism economics". We developed 3 societal structure projection engines and applied a system of dynamics language to estimate the future total population of Japan. The Japan total population reached a maximum in 2005, and thereafter depopulation begun. The populations in the younger working age group (from 25 to 54 years old) and those in the elderly working age group (from 55 to 84 years old) became almost equal in 2010. As economic growth rate depends upon an increase in the working population, the increase in national income rate of Japan approached over 10% per year between 1950 to 1970. The increased working age population of the same period exceeded 2.5% annually. However, after 2005 depopulation began in Japan. In future, national income will decrease proportional to the working age population, but personal national income will hold almost unchanged. We propose a new strategy for future society structure. The working age should be extended by 10 years. Labor power will come to exceed 60% of the population and will thereafter become stable.

The Growth of Older Inmate Populations: How Population Aging Explains Rising Age at Admission.

PubMed

Luallen, Jeremy; Cutler, Christopher

2017-09-01

Older inmates are the fastest growing segment of the prison population; however, the reasons for this are not well understood. One explanation is that the general population is aging, driving prison age distributions to change. For this article, we study the role of population aging in prison growth by investigating how the baby boom phenomenon of post-World War II has contributed to the growth of older inmate populations. We identify the impact of population aging using simulation methods that explain prison growth as the combination of criminal justice processes. Overall, we find evidence that population aging has played a significant role in explaining the growth of older inmate populations, in particular among inmates aged between 50 and 64 years, contributing to as much as half of the observed increase in these groups since 2000. This finding stands in contrast to the notion that population aging has little explanatory power in describing the growth of prison populations and implies that older inmate groups are more sensitive to compositional changes in the general population. We argue that prediction-based modeling of prison growth should more seriously consider the impacts and consequences of demographic shifts among older prisoner populations. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Age and growth of the mutton hamlet Alphestes afer, with a review of the size and age of sex change among epinephelids.

PubMed

Marques, S; Ferreira, B P

2016-07-01

This paper presents results on the age, growth and population structure of a small grouper, the mutton hamlet Alphestes afer, and discusses the observed size and age structure patterns in relation to reproductive strategies among the epinephelids. Ages were determined by examination of sectioned otoliths, which showed a distinct pattern of alternating translucent and opaque zones that formed annually, as validated with tetracycline labelling. The von Bertalanffy growth function was adjusted to the length-at-age data of the males and females, but no significant differences were observed between the resulting parameters. The females, however, were older at given sizes and attained larger sizes and ages, with a maximum observed longevity of 13 years and a total length (LT ) of 26 cm, while the males attained maximum longevities of only 10 years and a 22 cm maximum LT . The LT and age range for the sex change was 16-25 cm and 3-11 years. The total mortality rate (Z) was estimated to be 0·55 for females and 0·82 for males. With the males younger and smaller than the females, this species differed from the pattern commonly observed for protogynous epinephelids. Males had slower growth after maturation, probably due to energy allocation to sperm production during sexual development. This study shows that demography is an important tool to understand the pathways for reproductive strategies in grouper populations. © 2016 The Fisheries Society of the British Isles.

Ballistic aggregation in systems of inelastic particles: Cluster growth, structure, and aging

NASA Astrophysics Data System (ADS)

Paul, Subhajit; Das, Subir K.

2017-07-01

We study far-from-equilibrium dynamics in models of freely cooling granular gas and ballistically aggregating compact clusters. For both the cases, from event-driven molecular dynamics simulations, we have presented detailed results on structure and dynamics in space dimensions d =1 and 2. Via appropriate analyses it has been confirmed that the ballistic aggregation mechanism applies in d =1 granular gases as well. Aging phenomena for this mechanism, in both the dimensions, have been studied via the two-time density autocorrelation function. This quantity is demonstrated to exhibit scaling property similar to that in the standard phase transition kinetics. The corresponding functional forms have been quantified and the outcomes have been discussed in connection with the structural properties. Our results on aging establish a more complete equivalence between the granular gas and the ballistic aggregation models in d =1 .

Growth factors, nutrient signaling, and cardiovascular aging

PubMed Central

Fontana, Luigi; Vinciguerra, Manlio; Longo, Valter D.

2012-01-01

Growth factors regulated by specific macronutrients have been shown to promote aging and accelerate mortality in the great majority of the organisms studied. In particular, the enzymes activated by growth hormone (GH), insulin and insulin-like growth factor 1 (IGF-I) in mammals and their orthologs in simple model organisms represent perhaps the best-understood proteins involved in the aging process. Dietary restriction (DR), which reduces the level of IGF-I and of other growth factors, has been associated with protection from diabetes, cancer, and cardiovascular diseases and deficiencies in GH signaling and IGF-I are strongly associated with protection from cancer and diabetes in both mice and humans, but their role in cardiac function and cardiovascular diseases is controversial. Here we review the link between growth factors, cardiac function and heart disease with focus on the cardioprotective and sensitizing effect of growth factors in both model organisms and humans. PMID:22499903

Effect of growth hormone deficiency on brain structure, motor function and cognition.

PubMed

Webb, Emma A; O'Reilly, Michelle A; Clayden, Jonathan D; Seunarine, Kiran K; Chong, Wui K; Dale, Naomi; Salt, Alison; Clark, Chris A; Dattani, Mehul T

2012-01-01

The growth hormone-insulin-like growth factor-1 axis plays a role in normal brain growth but little is known of the effect of growth hormone deficiency on brain structure. Children with isolated growth hormone deficiency (peak growth hormone <6.7 µg/l) and idiopathic short stature (peak growth hormone >10 µg/l) underwent cognitive assessment, diffusion tensor imaging and volumetric magnetic resonance imaging prior to commencing growth hormone treatment. Total brain, corpus callosal, hippocampal, thalamic and basal ganglia volumes were determined using Freesurfer. Fractional anisotropy (a marker of white matter structural integrity) images were aligned and tract-based spatial statistics performed. Fifteen children (mean 8.8 years of age) with isolated growth hormone deficiency [peak growth hormone <6.7 µg/l (mean 3.5 µg/l)] and 14 controls (mean 8.4 years of age) with idiopathic short stature [peak growth hormone >10 µg/l (mean 15 µg/l) and normal growth rate] were recruited. Compared with controls, children with isolated growth hormone deficiency had lower Full-Scale IQ (P < 0.01), Verbal Comprehension Index (P < 0.01), Processing Speed Index (P < 0.05) and Movement-Assessment Battery for Children (P < 0.008) scores. Verbal Comprehension Index scores correlated significantly with insulin-like growth factor-1 (P < 0.03) and insulin-like growth factor binding protein-3 (P < 0.02) standard deviation scores in isolated growth hormone deficiency. The splenium of the corpus callosum, left globus pallidum, thalamus and hippocampus (P < 0.01) were significantly smaller; and corticospinal tract (bilaterally; P < 0.045, P < 0.05) and corpus callosum (P < 0.05) fractional anisotropy were significantly lower in the isolated growth hormone deficiency group. Basal ganglia volumes and bilateral corticospinal tract fractional anisotropy correlated significantly with Movement-Assessment Battery for Children scores, and

Direct Age Determination of a Subtropical Freshwater Crayfish (Redclaw, Cherax quadricarinatus) Using Ossicular Growth Marks

PubMed Central

Leland, Jesse C.; Bucher, Daniel J.; Coughran, Jason

2015-01-01

Recent studies have reported that crustacean age determination is possible. We applied a direct ageing method (i.e. transverse cross sectioning of gastric ossicles) to a subtropical freshwater crayfish (Cherax quadricarinatus) sourced from an aquaculture population. Growth mark periodicity and the potential for chronological depositions were investigated by staining C. quadricarinatus with calcein and examining their ossicles a year later. Pterocardiac ossicles were superior to other ageing structures (i.e. other ossicles and eyestalks) and produced repeatable between-reader counts (87% were corroborated and 13% varied by ±1). C. quadricarinatus size-at-age data (for an aquaculture population) was described by a von Bertalanffy growth equation (L ∞ = 32 mm occipital carapace length; K = 0.64; t 0 = –0.18; R2 = 0.81). Ossicular growth marks did not correspond to moult history. The calcein stain was retained over an annual cycle comprising multiple moults, demonstrating that pterocardiac ossicles retain chronological information. The maximum age (3+) corroborated other indirectly-obtained longevity estimates for C. quadricarinatus. Multiple lines of evidence indicate that the growth marks in C. quadricarinatus ossicles are probably deposited annually during winter. The ability to extract age information from subtropical decapods provides substantial opportunities for advancing fisheries and conservation research globally, but further research is needed to provide a definitive validation and elucidate the mechanism governing the accrual of ossicular growth marks. PMID:26309228

Stand and cohort structures of old-growth Pinus resinosa-dominated forests of northern Minnesota, USA

Treesearch

Shawn Fraver; Brian J. Palik

2012-01-01

The wide range of stand and age-cohort structures in these old-growth P. resinosa stands depicts pre-settlement forests more complex than those of the single-cohort, post-stand-replacing-fire model that has guided regional forest management. Within-stand patchiness of cohort age structures implies disturbances operating at scales smaller than...

The Impact of Policies Influencing the Demography of Age-Structured Populations: Lessons from Academies of Sciences

PubMed Central

Riosmena, Fernando; Winkler-Dworak, Maria; Prskawetz, Alexia; Feichtinger, Gustav

2013-01-01

In this paper, we assess the role of policies aimed at regulating the number and age structure of elections on the size and age structure of five European Academies of Sciences. We show the recent pace of ageing and the degree of variation in policies across them and discuss the implications of different policies on the size and age structure of academies. We also illustrate the potential effect of different election regimes (fixed vs. linked) and age structures of election (younger vs. older) by contrasting the steady-state dynamics of different projections of Full Members in each academy into 2070 and measuring the size and age-compositional effect of changing a given policy relative to a status quo policy scenario. Our findings suggest that academies with linked intake (i.e., where the size of the academy below a certain age is fixed and the number of elections is set to the number of members becoming that age) may be a more efficient approach to curb growth without suffering any ageing trade-offs relative to the faster growth of academies electing a fixed number of members per year. We further discuss the implications of our results in the context of stable populations open to migration. PMID:23843677

Age structured dynamical model for an endangered lizard Eulamprus leuraensis

NASA Astrophysics Data System (ADS)

Supriatna, A. K.; Rachmadani, Q.; Ilahi, F.; Anggriani, N.; Nuraini, N.

2014-02-01

The Blue Mountains Water Skink, Eulamprus leuraensis, is listed as an endangered species under the IUCN Red List. This lizard species has a typical characteristic of growth with a low fecundity. It is known that the offspring quality may decline with maternal age of the parents despite they can grow rapidly from neonatal size to adult size within two to three years. It is also believed that low adult survival rates and specialization on rare and fragmented type of habitat are the main cause leading to the endangered status of the lizard. A mathematical model with age structure for Eulamprus leuraensis, taking into account the variation of survival rate in each structure and the declining of offspring quality with respect to maternal age is considered here. Stable coexistence of non-trivial equilibriumis shown. It is also shown that an endangered status is due to combination oflow reproductive output and low rates of adult survival. Further, understanding the age structure within populations can facilitate efective management of the endangered species.

Growth Hormone Deficiency in the Transition Age.

PubMed

Loche, Sandro; Di Iorgi, Natascia; Patti, Giuseppa; Noli, Serena; Giaccardi, Marta; Olivieri, Irene; Ibba, Anastasia; Maghnie, Mohamad

2018-01-01

Growth hormone (GH) is essential not only for normal growth during childhood, but also for the acquisition of bone mass and muscle strength in both sexes. This process is completed after the achievement of adult height in the phase of transition from adolescence to adulthood. Adolescents with childhood onset GH deficiency (GHD) show reduction of bone mineral density, decrease in lean body mass, increase in fat mass, and deterioration of the lipid profile. For this reason, continuation of GH replacement therapy in the transition age is recommended in all patients with a confirmed diagnosis of GHD. To confirm the diagnosis of GHD, GH treatment should be discontinued for at least 1 month after the attainment of adult height, and the patient should be re-evaluated for GH secretion. Current guidelines indicate that retesting is not required for those with a transcription factor mutation, more than 3 pituitary hormone deficits, or isolated GHD associated with an identified mutation. The key predictors of persistent GHD are its severity, the presence of additional pituitary hormone deficits, low insulin-like growth factor I (IGF-I) concentration, and the presence of structural hypothalamic-pituitary abnormalities Treatment should be initiated with a low dose (0.2-0.5 mg/day s.c.) and then adjusted according to IGF-I concentrations. © 2018 S. Karger AG, Basel.

Age class, longevity and growth rate relationships: protracted growth increases in old trees in the eastern United States.

PubMed

Johnson, Sarah E; Abrams, Marc D

2009-11-01

This study uses data from the International Tree-Ring Data Bank website and tree cores collected in the field to explore growth rate (basal area increment, BAI) relationships across age classes (from young to old) for eight tree species in the eastern US. These species represent a variety of ecological traits and include those in the genera Populus, Quercus, Pinus, Tsuga and Nyssa. We found that most trees in all age classes and species exhibit an increasing BAI throughout their lives. This is particularly unusual for trees in the older age classes that we expected to have declining growth in the later years, as predicted by physiological growth models. There exists an inverse relationship between growth rate and increasing age class. The oldest trees within each species have consistently slow growth throughout their lives, implying an inverse relationship between growth rate and longevity. Younger trees (< 60 years of age) within each species are consistently growing faster than the older trees when they are of the same age resulting from a higher proportion of fast-growing trees in these young age classes. Slow, but increasing, BAI in the oldest trees in recent decades is a continuation of their growth pattern established in previous centuries. The fact that they have not shown a decreasing growth rate in their old age contradicts physiological growth models and may be related to the stimulatory effects of global change phenomenon (climate and land-use history).

Aging Theories for Establishing Safe Life Spans of Airborne Critical Structural Components

NASA Technical Reports Server (NTRS)

Ko, William L.

2003-01-01

New aging theories have been developed to establish the safe life span of airborne critical structural components such as B-52B aircraft pylon hooks for carrying air-launch drop-test vehicles. The new aging theories use the equivalent-constant-amplitude loading spectrum to represent the actual random loading spectrum with the same damaging effect. The crack growth due to random loading cycling of the first flight is calculated using the half-cycle theory, and then extrapolated to all the crack growths of the subsequent flights. The predictions of the new aging theories (finite difference aging theory and closed-form aging theory) are compared with the classical flight-test life theory and the previously developed Ko first- and Ko second-order aging theories. The new aging theories predict the number of safe flights as considerably lower than that predicted by the classical aging theory, and slightly lower than those predicted by the Ko first- and Ko second-order aging theories due to the inclusion of all the higher order terms.

Brain metabolite alterations in infants born preterm with intrauterine growth restriction: association with structural changes and neurodevelopmental outcome.

PubMed

Simões, Rui V; Muñoz-Moreno, Emma; Cruz-Lemini, Mónica; Eixarch, Elisenda; Bargalló, Núria; Sanz-Cortés, Magdalena; Gratacós, Eduard

2017-01-01

Intrauterine growth restriction and premature birth represent 2 independent problems that may occur simultaneously and contribute to impaired neurodevelopment. The objective of the study was to assess changes in the frontal lobe metabolic profiles of 1 year old intrauterine growth restriction infants born prematurely and adequate-for-gestational-age controls, both premature and term adequate for gestational age and their association with brain structural and biophysical parameters and neurodevelopmental outcome at 2 years. A total of 26 prematurely born intrauterine growth restriction infants (birthweight <10th centile for gestational age), 22 prematurely born but adequate for gestational age controls, and 26 term adequate-for-gestational-age infants underwent brain magnetic resonance imaging and magnetic resonance spectroscopy at 1 year of age during natural sleep, on a 3 Tesla scanner. All brain T1-weighted and diffusion-weighted images were acquired along with short echo time single-voxel proton spectra from the frontal lobe. Magnetic resonance imaging/magnetic resonance spectroscopy data were processed to derive structural, biophysical, and metabolic information, respectively. Neurodevelopment was evaluated at 2 years of age using the Bayley Scales 3rd edition, assessing cognitive, language, motor, socioemotional, and adaptive behavior. Prematurely born intrauterine growth restriction infants had slightly smaller brain volumes and increased frontal lobe white matter mean diffusivity compared with both prematurely born but adequate for gestational age and term adequate for gestational age controls. Frontal lobe N-acetylaspartate levels were significantly lower in prematurely born intrauterine growth restriction than in prematurely born but adequate for gestational age infants but increased in prematurely born but adequate for gestational age compared with term adequate-for-gestational-age infants. The prematurely born intrauterine growth restriction group also

Age- and sex-related growth patterns of the craniofacial complex in European children aged 3-6 years.

PubMed

Tutkuviene, Janina; Cattaneo, Cristina; Obertová, Zuzana; Ratnayake, Melanie; Poppa, Pasquale; Barkus, Arunas; Khalaj-Hedayati, Kerstin; Schroeder, Inge; Ritz-Timme, Stefanie

2016-11-01

Craniofacial growth changes in young children are not yet completely understood. Up-to-date references for craniofacial measurements are crucial for clinical assessment of orthodontic anomalies, craniofacial abnormalities and subsequent planning of interventions. To provide normal reference data and to identify growth patterns for craniofacial dimensions of European boys and girls aged 3-6 years. Using standard anthropometric methodology, body weight, body height and 23 craniofacial measurements were acquired for a cross-sectional sample of 681 healthy children (362 boys and 319 girls) aged 3-6 years from Germany, Italy and Lithuania. Descriptive statistics, correlation coefficients, percentage annual changes and percentage growth rates were used to analyse the dataset. Between the ages of 3-6 years, craniofacial measurements showed age- and sex-related patterns independent from patterns observed for body weight and body height. Sex-related differences were observed in the majority of craniofacial measurements. In both sexes, face heights and face depths showed the strongest correlation with age. Growth patterns differed by craniofacial measurement and can be summarised into eight distinct age- and sex-related patterns. This study provided reference data and identified sex- and age-related growth patterns of the craniofacial complex of young European children, which may be used for detailed assessment of normal growth in paediatrics, maxillofacial reconstructive surgery and possibly for forensic age assessment.

Age structure and cooperation in coevolutionary games on dynamic network

NASA Astrophysics Data System (ADS)

Qin, Zilong; Hu, Zhenhua; Zhou, Xiaoping; Yi, Jingzhang

2015-04-01

Our proposed model imitates the growth of a population and describes the age structure and the level of cooperation in games on dynamic network with continuous changes of structure and topology. The removal of nodes and links caused by age-dependent attack, together with the nodes addition standing for the newborns of population, badly ruins Matthew effect in this coevolutionary process. Though the network is generated by growth and preferential attachment, it degenerates into random network and it is no longer heterogeneous. When the removal of nodes and links is equal to the addition of nodes and links, the size of dynamic network is maintained in steady-state, so is the low level of cooperation. Severe structure variation, homogeneous topology and continuous invasion of new defection jointly make dynamic network unsuitable for the survival of cooperator even when the probability with which the newborn players initially adopt the strategy cooperation is high, while things change slightly when the connections of newborn players are restricted. Fortunately, moderate interactions in a generation trigger an optimal recovering process to encourage cooperation. The model developed in this paper outlines an explanation of the cohesion changes in the development process of an organization. Some suggestions for cooperative behavior improvement are given in the end.

Efficacy of otoliths and first dorsal spines for preliminary age and growth determination in Atlantic Tripletails

USGS Publications Warehouse

Parr, Russell T.; Bringolf, Robert B.; Jennings, Cecil A.

2018-01-01

The Atlantic Tripletail Lobotes surinamensis is a popular sport fish for which age and growth data are scarce in general and nonexistent for Georgia (GA), USA, waters. These data are necessary to ensure that management regulations are adequate to protect this species, especially given its popularity as a sport fish. We evaluated whether otoliths and spines were suitable for determining the estimated age (hereafter, “age”) and growth rates of Atlantic Tripletails, and we ascertained whether one method was more accurate than the other. Atlantic Tripletails were sampled by angling and trawling during March 30–August 10, 2009, and March 14–August 6, 2010, in nearshore GA waters of the Atlantic Ocean. During the study, 243 Atlantic Tripletails were captured and sampled for aging structures. Sagittal otoliths and the first dorsal spine were removed from each fish and used to estimate the age and growth rate. Mean differences in TL at age for spine and otolith data were evaluated with ANOVA. Estimated ages for males and females ranged from 1 to 5 years based on otoliths and spines. Both otolith and spine mean TLs at ages 1 and 2 were significantly different from each other as well as all other age‐classes, whereas mean TLs for ages 3–5 were not significantly different. Differences in Atlantic Tripletail TL among the otolith‐ and spine‐derived age‐classes were not significant. Each method used to age Atlantic Tripletails had advantages and disadvantages. Otoliths had higher initial reader agreement than spines, although agreement between the structures was 84.1%. However, otoliths require sacrifice of the fish, whereas a spine can be taken without sacrificing the fish. The lack of concrete life history data and population estimates suggests that when feasible, nonlethal aging methods would be preferred over lethal methods to ensure the survival of Atlantic Tripletail populations.

Crown structure and growth efficiency of red spruce in uneven-aged, mixed-species stands in Maine

Treesearch

Douglas A. Maguire; John C. Brissette; Lianhong. Gu

1998-01-01

Several hypotheses about the relationships among individual tree growth, tree leaf area, and relative tree size or position were tested with red spruce (Picea rubens Sarg.) growing in uneven-aged, mixed-species forests of south-central Maine, U.S.A. Based on data from 65 sample trees, predictive models were developed to (i)...

Effects of recruitment, growth, and exploitation on walleye population size structure in northern Wisconsin lakes

USGS Publications Warehouse

Hansen, Michael J.; Nate, Nancy A.

2014-01-01

We evaluated the dynamics of walleye Sander vitreus population size structure, as indexed by the proportional size distribution (PSD) of quality-length fish, in Escanaba Lake during 1967–2003 and in 204 other lakes in northern Wisconsin during 1990–2011. We estimated PSD from angler-caught walleyes in Escanaba Lake and from spring electrofishing in 204 other lakes, and then related PSD to annual estimates of recruitment to age-3, length at age 3, and annual angling exploitation rate. In Escanaba Lake during 1967–2003, annual estimates of PSD were highly dynamic, growth (positively) explained 35% of PSD variation, recruitment explained only 3% of PSD variation, and exploitation explained only 7% of PSD variation. In 204 other northern Wisconsin lakes during 1990–2011, PSD varied widely among lakes, recruitment (negatively) explained 29% of PSD variation, growth (positively) explained 21% of PSD variation, and exploitation explained only 4% of PSD variation. We conclude that population size structure was most strongly driven by recruitment and growth, rather than exploitation, in northern Wisconsin walleye populations. Studies of other species over wide spatial and temporal ranges of recruitment, growth, and mortality are needed to determine which dynamic rate most strongly influences population size structure of other species. Our findings indicate a need to be cautious about assuming exploitation is a strong driver of walleye population size structure.

A growth reference for mid upper arm circumference for age among school age children and adolescents, and validation for mortality: growth curve construction and longitudinal cohort study

PubMed Central

Mramba, Lazarus; Ngari, Moses; Mwangome, Martha; Muchai, Lilian; Bauni, Evasius; Walker, A Sarah; Gibb, Diana M; Fegan, Gregory

2017-01-01

Objectives To construct growth curves for mid-upper-arm circumference (MUAC)-for-age z score for 5-19 year olds that accord with the World Health Organization growth standards, and to evaluate their discriminatory performance for subsequent mortality. Design Growth curve construction and longitudinal cohort study. Setting United States and international growth data, and cohorts in Kenya, Uganda, and Zimbabwe. Participants The Health Examination Survey (HES)/National Health and Nutrition Examination Survey (NHANES) US population datasets (age 5-25 years), which were used to construct the 2007 WHO growth reference for body mass index in this age group, were merged with an imputed dataset matching the distribution of the WHO 2006 growth standards age 2-6 years. Validation data were from 685 HIV infected children aged 5-17 years participating in the Antiretroviral Research for Watoto (ARROW) trial in Uganda and Zimbabwe; and 1741 children aged 5-13 years discharged from a rural Kenyan hospital (3.8% HIV infected). Both cohorts were followed-up for survival during one year. Main outcome measures Concordance with WHO 2006 growth standards at age 60 months and survival during one year according to MUAC-for-age and body mass index-for-age z scores. Results The new growth curves transitioned smoothly with WHO growth standards at age 5 years. MUAC-for-age z scores of −2 to −3 and less than−3, compared with −2 or more, was associated with hazard ratios for death within one year of 3.63 (95% confidence interval 0.90 to 14.7; P=0.07) and 11.1 (3.40 to 36.0; P<0.001), respectively, among ARROW trial participants; and 2.22 (1.01 to 4.9; P=0.04) and 5.15 (2.49 to 10.7; P<0.001), respectively, among Kenyan children after discharge from hospital. The AUCs for MUAC-for-age and body mass index-for-age z scores for discriminating subsequent mortality were 0.81 (95% confidence interval 0.70 to 0.92) and 0.75 (0.63 to 0.86) in the ARROW trial (absolute difference 0.06, 95

Effects of induced placental and fetal growth restriction, size at birth and early neonatal growth on behavioural and brain structural lateralization in sheep.

PubMed

Hunter, Damien Seth; Hazel, Susan J; Kind, Karen L; Liu, Hong; Marini, Danila; Giles, Lynne C; De Blasio, Miles J; Owens, Julie A; Pitcher, Julia B; Gatford, Kathryn L

2017-09-01

Poor perinatal growth in humans results in asymmetrical grey matter loss in fetuses and infants and increased functional and behavioural asymmetry, but specific contributions of pre- and postnatal growth are unclear. We therefore compared strength and direction of lateralization in obstacle avoidance and maze exit preference tasks in offspring of placentally restricted (PR: 10M, 13F) and control (CON: 23M, 17F) sheep pregnancies at 18 and 40 weeks of age, and examined gross brain structure of the prefrontal cortex at 52 weeks of age (PR: 14M, 18F; CON: 23M, 25F). PR did not affect lateralization direction, but 40-week-old PR females had greater lateralization strength than CON (P = .021). Behavioural lateralization measures were not correlated with perinatal growth. PR did not alter brain morphology. In males, cross-sectional areas of the prefrontal cortex and left hemisphere correlated positively with skull width at birth, and white matter area correlated positively with neonatal growth rate of the skull (all P < .05). These studies reinforce the need to include progeny of both sexes in future studies of neurodevelopmental programming, and suggest that restricting in utero growth has relatively mild effects on gross brain structural or behavioural lateralization in sheep.

Comparative age and growth of common snook Centropomus undecimalis (Pisces: Centropomidae) from coastal and riverine areas in Southern Mexico.

PubMed

Perera-Garcia, Martha A; Mendoza-Carranza, Manuel; Contreras-Sánchez, Wilfrido; Ferrara, Allyse; Huerta-Ortiz, Maricela; Hernández-Gómez, Raúl E

2013-06-01

Common snook Centropomus unidecimalis is an important commercial and fishery species in Southern Mexico, however the high exploitation rates have resulted in a strong reduction of its abundances. Since, the information about its population structure is scarce, the objective of the present research was to determine and compare the age structure in four important fishery sites. For this, age and growth of common snook were determined from specimens collected monthly, from July 2006 to March 2008, from two coastal (Barra Bosque and Barra San Pedro) and two riverine (San Pedro and Tres Brazos) commercial fishery sites in Tabasco, Mexico. Age was determined using sectioned saggitae otoliths and data analyzed by von Bertalanffy and Levenberg-Marquardt among others. Estimated ages ranged from 2 to 17 years. Monthly patterns of marginal increment formation and the percentage of otoliths with opaque rings on the outer edge demonstrated that a single annulus was formed each year. The von Bertalanffy parameters were calculated for males and females using linear adjustment and the non-linear method of Levenberg-Marquardt. The von Bertalanffy growth equations were FLt = 109.21(1-e-0.2(t+0.57)) for Barra Bosque, FLt = 94.56(1-e-027(t+0.485)) for Barra San Pedro, FLt = 97.15(1-e 0.17(t + 1.32)) for San Pedro and FLt = 83.77(1-e-026(t + 0.49)) for Tres Brazos. According to (Hotelling's T2, p < 0.05) test growth was significantly greater for females than for males. Based on the Chen test, von Bertalanffy growth curves were different among the study sites (RSS, p < 0.05). Based on the observed differences in growth parameters among sampling sites (coastal and riverine environments) future research need to be conducted on migration and population genetics, in order to delineate the stock structure of this population and support management programs.

Are gestational age, birth weight, and birth length indicators of favorable fetal growth conditions? A structural equation analysis of Filipino infants.

PubMed

Bollen, Kenneth A; Noble, Mark D; Adair, Linda S

2013-07-30

The fetal origins hypothesis emphasizes the life-long health impacts of prenatal conditions. Birth weight, birth length, and gestational age are indicators of the fetal environment. However, these variables often have missing data and are subject to random and systematic errors caused by delays in measurement, differences in measurement instruments, and human error. With data from the Cebu (Philippines) Longitudinal Health and Nutrition Survey, we use structural equation models, to explore random and systematic errors in these birth outcome measures, to analyze how maternal characteristics relate to birth outcomes, and to take account of missing data. We assess whether birth weight, birth length, and gestational age are influenced by a single latent variable that we call favorable fetal growth conditions (FFGC) and if so, which variable is most closely related to FFGC. We find that a model with FFGC as a latent variable fits as well as a less parsimonious model that has birth weight, birth length, and gestational age as distinct individual variables. We also demonstrate that birth weight is more reliably measured than is gestational age. FFGCs were significantly influenced by taller maternal stature, better nutritional stores indexed by maternal arm fat and muscle area during pregnancy, higher birth order, avoidance of smoking, and maternal age 20-35 years. Effects of maternal characteristics on newborn weight, length, and gestational age were largely indirect, operating through FFGC. Copyright © 2013 John Wiley & Sons, Ltd.

The effect of clinorotation on structural and functional organization of assimilative tissues, cells and growth regulator activity in orchids of different age

NASA Astrophysics Data System (ADS)

Cherevchenko, T.; Zaimenko, N.; Sitnyanska, N.; Majko, T.; Grishko, M. M.

Ultrastructural analyses of assimilative tissues of the orchids, Cymbidium hybridum and Doritis pulcherrima, show that, in plants of different age, chloroplasts differ in structure and stage of membrane system development. Variability was found in the number, size and electron density of plastoglobuli, and in the orientation and length of thylakoid membranes. We consider significant the increase of the plastoglobuli which completely fill the stroma of chloroplasts in cells of old leaves and, under conditions of clinorotation (using a horizontal clinostat at 3 r.p.m.), are able to block membrane function. In the early stages of orchid plant development, the content of substances with auxin-like activity (as judged by bioassay) in the leaves was low, but increased with age. Clinorotation resulted in a sharp decrease of their content. There was a concomitant increase in the content of growth inhibitors of a phenolic nature.

Growth characteristics and Otolith analysis on Age-0 American Shad

USGS Publications Warehouse

Sauter, Sally T.; Wetzel, Lisa A.

2011-01-01

Otolith microstructure analysis provides useful information on the growth history of fish (Campana and Jones 1992, Bang and Gronkjaer 2005). Microstructure analysis can be used to construct the size-at-age growth trajectory of fish, determine daily growth rates, and estimate hatch date and other ecologically important life history events (Campana and Jones 1992, Tonkin et al. 2008). This kind of information can be incorporated into bioenergetics modeling, providing necessary data for estimating prey consumption, and guiding the development of empirically-based modeling scenarios for hypothesis testing. For example, age-0 American shad co-occur with emigrating juvenile fall Chinook salmon originating from Hanford Reach and the Snake River in the lower Columbia River reservoirs during the summer and early fall. The diet of age-0 American shad appears to overlap with that of juvenile fall Chinook salmon (Chapter 1, this report), but juvenile fall Chinook salmon are also known to feed on age-0 American shad in the reservoirs (USGS unpublished data). Abundant, energy-dense age-0 American shad may provide juvenile fall Chinook salmon opportunities for rapid growth during the time period when large numbers of age-0 American shad are available. Otolith analysis of hatch dates and the growth curve of age-0 American shad could be used to identify when eggs, larvae, and juveniles of specific size classes are temporally available as food for fall Chinook salmon in the lower Columbia River reservoirs. This kind of temporally and spatially explicit life history information is important to include in bioenergetics modeling scenarios. Quantitative estimates of prey consumption could be used with spatially-explicit estimates of prey abundance to construct a quantitative assessment of the age-0 American shad impact on a reservoir food web.

Brain Structure and Function Associated with Younger Adults in Growth Hormone Receptor-Deficient Humans

PubMed Central

Nashiro, Kaoru; Braskie, Meredith N.; Velasco, Rico; Balasubramanian, Priya; Wei, Min; Thompson, Paul M.; Nelson, Marvin D.; Guevara, Alexandra

2017-01-01

Growth hormone receptor deficiency (GHRD) results in short stature, enhanced insulin sensitivity, and low circulating levels of insulin and insulin-like growth factor 1 (IGF-1). Previous studies in mice and humans suggested that GHRD has protective effects against age-related diseases, including cancer and diabetes. Whereas GHRD mice show improved age-dependent cognitive performance, the effect of GHRD on human cognition remains unknown. Using MRI, we compared brain structure, function, and connectivity between 13 people with GHRD and 12 unaffected relatives. We assessed differences in white matter microstructural integrity, hippocampal volume, subregional volumes, and cortical thickness and surface area of selected regions. We also evaluated brain activity at rest and during a hippocampal-dependent pattern separation task. The GHRD group had larger surface areas in several frontal and cingulate regions and showed trends toward larger dentate gyrus and CA1 regions of the hippocampus. They had lower mean diffusivity in the genu of the corpus callosum and the anterior thalamic tracts. The GHRD group showed enhanced cognitive performance and greater task-related activation in frontal, parietal, and hippocampal regions compared with controls. Furthermore, they had greater functional synchronicity of activity between the precuneus and the rest of the default mode network at rest. The results suggest that, compared with controls, GHRD subjects have brain structure and function that are more consistent with those observed in younger adults reported in previous studies. Further investigation may lead to improved understanding of underlying mechanisms and could contribute to the identification of treatments for age-related cognitive deficits. SIGNIFICANCE STATEMENT People and mice with growth hormone receptor deficiency (GHRD or Laron syndrome) are protected against age-related diseases including cancer and diabetes. However, in humans, it is unknown whether cognitive

A growth reference for mid upper arm circumference for age among school age children and adolescents, and validation for mortality: growth curve construction and longitudinal cohort study.

PubMed

Mramba, Lazarus; Ngari, Moses; Mwangome, Martha; Muchai, Lilian; Bauni, Evasius; Walker, A Sarah; Gibb, Diana M; Fegan, Gregory; Berkley, James A

2017-08-03

Objectives  To construct growth curves for mid-upper-arm circumference (MUAC)-for-age z score for 5-19 year olds that accord with the World Health Organization growth standards, and to evaluate their discriminatory performance for subsequent mortality. Design  Growth curve construction and longitudinal cohort study. Setting  United States and international growth data, and cohorts in Kenya, Uganda, and Zimbabwe. Participants  The Health Examination Survey (HES)/National Health and Nutrition Examination Survey (NHANES) US population datasets (age 5-25 years), which were used to construct the 2007 WHO growth reference for body mass index in this age group, were merged with an imputed dataset matching the distribution of the WHO 2006 growth standards age 2-6 years. Validation data were from 685 HIV infected children aged 5-17 years participating in the Antiretroviral Research for Watoto (ARROW) trial in Uganda and Zimbabwe; and 1741 children aged 5-13 years discharged from a rural Kenyan hospital (3.8% HIV infected). Both cohorts were followed-up for survival during one year. Main outcome measures  Concordance with WHO 2006 growth standards at age 60 months and survival during one year according to MUAC-for-age and body mass index-for-age z scores. Results  The new growth curves transitioned smoothly with WHO growth standards at age 5 years. MUAC-for-age z scores of -2 to -3 and less than-3, compared with -2 or more, was associated with hazard ratios for death within one year of 3.63 (95% confidence interval 0.90 to 14.7; P=0.07) and 11.1 (3.40 to 36.0; P<0.001), respectively, among ARROW trial participants; and 2.22 (1.01 to 4.9; P=0.04) and 5.15 (2.49 to 10.7; P<0.001), respectively, among Kenyan children after discharge from hospital. The AUCs for MUAC-for-age and body mass index-for-age z scores for discriminating subsequent mortality were 0.81 (95% confidence interval 0.70 to 0.92) and 0.75 (0.63 to 0.86) in the ARROW trial (absolute difference 0.06, 95

Growth characteristics and otolith analysis on age-0 American shad

USGS Publications Warehouse

Sauter, Sally T.; Wetzel, Lisa A.

2011-01-01

Otolith microstructure analysis provides useful information on the growth history of fish (Campana and Jones 1992, Bang and Gronkjaer 2005). Microstructure analysis can be used to construct the size-at-age growth trajectory of fish, determine daily growth rates, and estimate hatch date and other ecologically important life history events (Campana and Jones 1992, Tonkin et al. 2008). This kind of information can be incorporated into bioenergetics modeling, providing necessary data for estimating prey consumption, and guiding the development of empirically-based modeling scenarios for hypothesis testing. For example, age-0 American shad co-occur with emigrating juvenile fall Chinook salmon originating from Hanford Reach and the Snake River in the lower Columbia River reservoirs during the summer and early fall. The diet of age-0 American shad appears to overlap with that of juvenile fall Chinook salmon (Chapter 1, this reoprt), but juvenile fall Chinook salmon are also known to feed on age-0 American shad in the reservoirs (USGS unpublished data). Abundant, energy-dense age-0 American shad may provide juvenile fall Chinook salmon opportunities for rapid growth during the time period when large number of age-0 American shad are available. Otolith analysis of hatch dates and the growth curve of age-0 American shad could be used to identify when eggs, larvae, and juveniles of specific size classes are temporally available as food for fall Chinook salmon in the lower Columbia River reservoirs. This kind of temporally and spatially explicit life history information is important to include in bioenergetics modeling scenarios. Quantitive estimates of prey consumption could be used with spatially-explicit estimates of prey abundance to construct a quantitative assessment of the age-0 American shad impact on a reservoir food web.

Analysis of the age-0 American shad growth trajectory or individual growth records may show evidence of differential growth rates over

Structural development of redwood branches and its effects on wood growth.

PubMed

Kramer, Russell D; Sillett, Stephen C; Carroll, Allyson L

2014-03-01

Redwood branches provide all the carbohydrates for the most carbon-heavy forests on Earth, and recent whole-tree measurements have quantified trunk growth rates associated with complete branch inventories. Providing all of a tree's photosynthetic capacity, branches represent an increasing proportion of total aboveground wood production as trees enlarge. To examine branch development and its effects on wood volume growth, we dissected 31 branches from eight Sequoia sempervirens (D. Don) Endl. and seven Sequoiadendron giganteum Lindl. trees. The cambium-area-to-leaf-area ratio was maintained with size and age but increased with light availability, whereas the heartwood-deposition-area-to-leaf-area ratio increased with size and age but was insensitive to light availability. The proportion of foliage mass arrayed in <1-cm-diameter epicormic shoots increased with decreasing light and was higher in Sequoia (20-60%) than in Sequoiadendron (3-16%). Well-illuminated branches concentrated leaves higher and distally, while shaded branches distributed leaves lower and proximally. In similar light environments, older branches distributed leaves lower and more proximally than younger branches. Branch size, light, species, heartwood area, a heartwood-area-species interaction, and ovulate cone mass predicted 87.5% of the variability in wood volume growth of branches. After accounting for the positive effects of size and light, wood volume growth declined with heartwood area and age. The effect of age was trivial compared to the effect of heartwood area, suggesting that heartwood expansion caused the age-related decline in wood volume growth. Additionally, Sequoiadendron branches of similar size and light environment with more ovulate cones produced less wood, even though these cones were long-lived and photosynthetic, reflecting the energetic cost of seed production. These results contributed to a conceptual model of branch development in which light availability, injury

The satisfactory growth and development at 2 years of age of the INTERGROWTH-21st Fetal Growth Standards cohort support its appropriateness for constructing international standards.

PubMed

Villar, José; Cheikh Ismail, Leila; Staines Urias, Eleonora; Giuliani, Francesca; Ohuma, Eric O; Victora, Cesar G; Papageorghiou, Aris T; Altman, Douglas G; Garza, Cutberto; Barros, Fernando C; Puglia, Fabien; Ochieng, Roseline; Jaffer, Yasmin A; Noble, Julia A; Bertino, Enrico; Purwar, Manorama; Pang, Ruyan; Lambert, Ann; Chumlea, Cameron; Stein, Alan; Fernandes, Michelle; Bhutta, Zulfiqar A; Kennedy, Stephen H

2018-02-01

The World Health Organization recommends that human growth should be monitored with the use of international standards. However, in obstetric practice, we continue to monitor fetal growth using numerous local charts or equations that are based on different populations for each body structure. Consistent with World Health Organization recommendations, the INTERGROWTH-21 st Project has produced the first set of international standards to date pregnancies; to monitor fetal growth, estimated fetal weight, Doppler measures, and brain structures; to measure uterine growth, maternal nutrition, newborn infant size, and body composition; and to assess the postnatal growth of preterm babies. All these standards are based on the same healthy pregnancy cohort. Recognizing the importance of demonstrating that, postnatally, this cohort still adhered to the World Health Organization prescriptive approach, we followed their growth and development to the key milestone of 2 years of age. The purpose of this study was to determine whether the babies in the INTERGROWTH-21 st Project maintained optimal growth and development in childhood. In the Infant Follow-up Study of the INTERGROWTH-21 st Project, we evaluated postnatal growth, nutrition, morbidity, and motor development up to 2 years of age in the children who contributed data to the construction of the international fetal growth, newborn infant size and body composition at birth, and preterm postnatal growth standards. Clinical care, feeding practices, anthropometric measures, and assessment of morbidity were standardized across study sites and documented at 1 and 2 years of age. Weight, length, and head circumference age- and sex-specific z-scores and percentiles and motor development milestones were estimated with the use of the World Health Organization Child Growth Standards and World Health Organization milestone distributions, respectively. For the preterm infants, corrected age was used. Variance components analysis was

Age, growth, and size of Lake Superior Pygmy Whitefish (Prosopium coulterii)

USGS Publications Warehouse

Stewart, Taylor; Derek Ogle,; Gorman, Owen T.; Vinson, Mark

2016-01-01

Pygmy Whitefish (Prosopium coulterii) are a small, glacial relict species with a disjunct distribution in North America and Siberia. In 2013 we collected Pygmy Whitefish at 28 stations from throughout Lake Superior. Total length was recorded for all fish and weight and sex were recorded and scales and otoliths were collected from a subsample. We compared the precision of estimated ages between readers and between scales and otoliths, estimated von Bertalanffy growth parameters for male and female Pygmy Whitefish, and reported the first weight-length relationship for Pygmy Whitefish. Age estimates between scales and otoliths differed significantly with otolith ages significantly greater for most ages after age-3. Maximum otolith age was nine for females and seven for males, which is older than previously reported for Pygmy Whitefish from Lake Superior. Growth was initially fast but slowed considerably after age-3 for males and age-4 for females, falling to 3–4 mm per year at maximum estimated ages. Females were longer than males after age-3. Our results suggest the size, age, and growth of Pygmy Whitefish in Lake Superior have not changed appreciably since 1953.

Age and growth of pike (Esox lucius) in Chivyrkui Bay, Lake Baikal

USGS Publications Warehouse

Owens, Randall W.; Pronin, Nikolai M.

2000-01-01

The purpose of this study was to describe age and growth of pike (Esox lucius) in Lake Baikal. Pike were collected with gill nets and by angling in Chivyrkui Bay in late July-early August 1993 and by gill nets in June 1995. Total length (mm), weight (g), and sex were recorded and scales and cleithra were collected for aging. In 1993, pike, ages 1 to 3, ranged in length from 331 to 810 mm and in 1995 , pike, ages 2 to 10, ranged in length from 365 to 1,111 mm but only three percent were age 7 or older. Most growth in length occurred during the first two years of life. The length-weight relation for pike from Chivyrkui Bay was similar to that of pike from the St. Lawrence River. Calculated total length of pike from Lake Baikal equalled or exceeded the lengths of pike from lakes Erie or Ontario. Good agreement was found between ages from cleithra and from scales. Lengths at age in June 1995 (N=108) varied widely among pike. Females were generally larger than males at a given age among fish age-3 and older. When compared with the circumpolar growth standard, based on the von Bertalanffy growth curve, growth of Lake Baikal pike exceeded all other Asian populations, and equalled or exceeded many other northern hemisphere populations.

Intrauterine growth restriction programs an accelerated age-related increase in cardiovascular risk in male offspring

PubMed Central

Dasinger, John Henry; Intapad, Suttira; Backstrom, Miles A.; Carter, Anthony J.

2016-01-01

Placental insufficiency programs an increase in blood pressure associated with a twofold increase in serum testosterone in male growth-restricted offspring at 4 mo of age. Population studies indicate that the inverse relationship between birth weight and blood pressure is amplified with age. Thus, we tested the hypothesis that intrauterine growth restriction programs an age-related increase in blood pressure in male offspring. Growth-restricted offspring retained a significantly higher blood pressure at 12 but not at 18 mo of age compared with age-matched controls. Blood pressure was significantly increased in control offspring at 18 mo of age relative to control counterparts at 12 mo; however, blood pressure was not increased in growth-restricted at 18 mo relative to growth-restricted counterparts at 12 mo. Serum testosterone levels were not elevated in growth-restricted offspring relative to control at 12 mo of age. Thus, male growth-restricted offspring no longer exhibited a positive association between blood pressure and testosterone at 12 mo of age. Unlike hypertension in male growth-restricted offspring at 4 mo of age, inhibition of the renin-angiotensin system with enalapril (250 mg/l for 2 wk) did not abolish the difference in blood pressure in growth-restricted offspring relative to control counterparts at 12 mo of age. Therefore, these data suggest that intrauterine growth restriction programs an accelerated age-related increase in blood pressure in growth-restricted offspring. Furthermore, this study suggests that the etiology of increased blood pressure in male growth-restricted offspring at 12 mo of age differs from that at 4 mo of age. PMID:27147668

Radiocarbon Based Ages and Growth Rates: Hawaiian Deep Sea Corals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roark, E B; Guilderson, T P; Dunbar, R B

2006-01-13

The radial growth rates and ages of three different groups of Hawaiian deep-sea 'corals' were determined using radiocarbon measurements. Specimens of Corallium secundum, Gerardia sp., and Leiopathes glaberrima, were collected from 450 {+-} 40 m at the Makapuu deep-sea coral bed using a submersible (PISCES V). Specimens of Antipathes dichotoma were collected at 50 m off Lahaina, Maui. The primary source of carbon to the calcitic C. secundum skeleton is in situ dissolved inorganic carbon (DIC). Using bomb {sup 14}C time markers we calculate radial growth rates of {approx} 170 {micro}m y{sup -1} and ages of 68-75 years on specimensmore » as tall as 28 cm of C. secundum. Gerardia sp., A. dichotoma, and L. glaberrima have proteinaceous skeletons and labile particulate organic carbon (POC) is their primary source of architectural carbon. Using {sup 14}C we calculate a radial growth rate of 15 {micro}m y{sup -1} and an age of 807 {+-} 30 years for a live collected Gerardia sp., showing that these organisms are extremely long lived. Inner and outer {sup 14}C measurements on four sub-fossil Gerardia spp. samples produce similar growth rate estimates (range 14-45 {micro}m y{sup -1}) and ages (range 450-2742 years) as observed for the live collected sample. Similarly, with a growth rate of < 10 {micro}m y{sup -1} and an age of {approx}2377 years, L. glaberrima at the Makapuu coral bed, is also extremely long lived. In contrast, the shallow-collected A. dichotoma samples yield growth rates ranging from 130 to 1,140 {micro}m y{sup -1}. These results show that Hawaiian deep-sea corals grow more slowly and are older than previously thought.« less

Age validation and variation in growth, mortality and population structure of Liza argentea and Myxus elongatus (Mugilidae) in two temperate Australian estuaries.

PubMed

Kendall, B W; Gray, C A; Bucher, D

2009-12-01

This study investigated variation in the rates of growth and mortality, and age and fork-length (L(F)) compositions of two exploited species of Mugilidae, Liza argentea and Myxus elongatus, in two south-east Australian estuaries (Lake Macquarie and St Georges Basin). An ageing protocol was developed by counting opaque growth zones on sectioned otoliths which was validated by periodically examining the otoliths of captive-reared young-of-the-year fishes, and marginal increment analysis of wild fishes. The maximum recorded age was 17 years for L. argentea and 12 years for M. elongatus, which is greater than generally observed in other species of mugilids. Growth models of each species significantly differed between sexes and, except for male L. argentea, between estuaries. Fishes from Lake Macquarie generally had a greater mean L(F) at age than those from St Georges Basin and females of both species generally attained a greater maximum L(F) and age than males. Gillnet catches of L. argentea were of similar L(F) and age compositions in both estuaries, whereas the age composition of catches of M. elongatus in Lake Macquarie contained a greater proportion of younger fish. Estimates of total, natural and fishing mortality were greater for M. elongatus than L. argentea across both estuaries, and estimates of total mortality were greatest for both species in Lake Macquarie. The data indicate that neither species has been overfished in these estuaries.

Communication Profile of Primary School-Aged Children with Foetal Growth Restriction

ERIC Educational Resources Information Center

Partanen, Lea Aulikki; Olsén, Päivi; Mäkikallio, Kaarin; Korkalainen, Noora; Heikkinen, Hanna; Heikkinen, Minna; Yliherva, Anneli

2017-01-01

Foetal growth restriction is associated with problems in neurocognitive development. In the present study, prospectively collected cohorts of foetal growth restricted (FGR) and appropriate for gestational age grown (AGA) children were examined at early school-age by using the Children's Communication Checklist-2 (CCC-2) to test the hypothesis that…

Age, growth, and mortality of introduced flathead catfish in Atlantic rivers and a review of other populations

USGS Publications Warehouse

Kwak, T.J.; Pine, William E.; Waters, D.S.

2006-01-01

Knowledge of individual growth and mortality rates of an introduced fish population is required to determine the success and degree of establishment as well as to predict the fish's impact on native fauna. The age and growth of flathead catfish Pylodictis olivaris have been studied extensively in the species' native and introduced ranges, and estimates have varied widely. We quantified individual growth rates and age structure of three introduced flathead catfish populations in North Carolina's Atlantic slope rivers using sagittal otoliths, determined trends in growth rates over time, compared these estimates among rivers in native and introduced ranges, and determined total mortality rates for each population. Growth was significantly faster in the Northeast Cape Fear River (NECFR) than in the Lumber and Neuse rivers. Fish in the NECFR grew to a total length of 700 mm by age 7, whereas fish in the Neuse and Lumber river populations reached this length by 8 and 10 years, respectively. The growth rates of fish in all three rivers were consistently higher than those of native riverine populations, similar to those of native reservoir populations, and slower than those of other introduced riverine populations. In general, recent cohorts (1998-2001 year-classes) in these three rivers exhibited slower growth among all ages than did cohorts previous to the 1998 year-class. The annual total mortality rate was similar among the three rivers, ranging from 0.16 to 0.20. These mortality estimates are considerably lower than those from the Missouri and Mississippi rivers, suggesting relatively low fishing mortality for these introduced populations. Overall, flathead catfish populations in reservoirs grow faster than those in rivers, the growth rates of introduced populations exceed those of native populations, and eastern United States populations grow faster than those in western states. Such trends constitute critical information for understanding and managing local

An age-structured extension to the vectorial capacity model.

PubMed

Novoseltsev, Vasiliy N; Michalski, Anatoli I; Novoseltseva, Janna A; Yashin, Anatoliy I; Carey, James R; Ellis, Alicia M

2012-01-01

Vectorial capacity and the basic reproductive number (R(0)) have been instrumental in structuring thinking about vector-borne pathogen transmission and how best to prevent the diseases they cause. One of the more important simplifying assumptions of these models is age-independent vector mortality. A growing body of evidence indicates that insect vectors exhibit age-dependent mortality, which can have strong and varied affects on pathogen transmission dynamics and strategies for disease prevention. Based on survival analysis we derived new equations for vectorial capacity and R(0) that are valid for any pattern of age-dependent (or age-independent) vector mortality and explore the behavior of the models across various mortality patterns. The framework we present (1) lays the groundwork for an extension and refinement of the vectorial capacity paradigm by introducing an age-structured extension to the model, (2) encourages further research on the actuarial dynamics of vectors in particular and the relationship of vector mortality to pathogen transmission in general, and (3) provides a detailed quantitative basis for understanding the relative impact of reductions in vector longevity compared to other vector-borne disease prevention strategies. Accounting for age-dependent vector mortality in estimates of vectorial capacity and R(0) was most important when (1) vector densities are relatively low and the pattern of mortality can determine whether pathogen transmission will persist; i.e., determines whether R(0) is above or below 1, (2) vector population growth rate is relatively low and there are complex interactions between birth and death that differ fundamentally from birth-death relationships with age-independent mortality, and (3) the vector exhibits complex patterns of age-dependent mortality and R(0) ∼ 1. A limiting factor in the construction and evaluation of new age-dependent mortality models is the paucity of data characterizing vector mortality patterns

Fetal growth restriction: relation to growth and obesity at the age of 9 years.

PubMed

Chakraborty, Supratik; Joseph, Desaline Veronica; Bankart, Michael John Gordon; Petersen, Stewart A; Wailoo, Michael P

2007-11-01

To assess growth patterns of 9-year-old children, some of whom had intrauterine growth restriction (IUGR). 75 9-year-old children (41 were IUGR infants) were weighed and measured at birth, at 1 year, at 2 years and at 9 years of age. Using general linear models for continuous data, changes in weight z scores were used to quantify growth rate between birth and 9 years of age. IUGR children were smaller at birth (weight z score -2.1 v 0.2 in normal children; p<0.001) but showed a greater increase in their weight between birth and 9 years (change of weight z score 1.5 v 0.4 in normal children; p = 0.001). At the age of 9 years the weight, height and body mass index (BMI) z scores were lower in IUGR children than the control children (weight z score -0.4 v 0.6, respectively; p<0.001, height z score -0.5 v 0, respectively; p = 0.002, BMI z score -0.2 v 0.7, respectively; p = 0.002). The predictors of these differences were IUGR, birth weight and maternal and paternal heights. IUGR infants grow faster but remain shorter and lighter than their normal counterparts-that is, they fail to fully catch up by 9 years of age.

Age and growth of the whitefish in Lake Superior

USGS Publications Warehouse

Dryer, William R.

1963-01-01

The average annual commercial production of whitefish in the U.S. waters of Lake Superior dropped from 2,194,000 pounds in 1879-1908 to 504,000 pounds in 1911-59. The modern production, though far below the earlier, has accounted for more than 10 percent of the total value of the fishery in all but one of the last 20 years. Data are given on growth rate, age and year-class composition, size distribution, and length-weight relation of 1,800 fish collected in 1957-59 at Bayfield, Wis., and Marquette, Whitefish Point, and Dollar Settlement, Mich. Studies of the body-scale relation, sex ratio, and age and size at maturity were limited to fish collected at Bayfield. The age composition and mean age varied widely by port and year of capture. Oldest fish were those of the 1957 Bayfield samples which were dominated by age group VII and averaged 5.5 years old. The youngest were from Whitefish Point in 1959; age-group III was dominant, and the mean age was 3.2 years. The evidence on the strength of year classes was not clear-cut, but it was obvious that fluctuations in stocks of different areas were largely independent. The percentage of legal-size fish (17 inches or longer) in age groups ranged widely; only 8.6 percent of the V group were legal in the 1957 Bayfield collections, whereas 100 percent of fish of the same age were legal in the 1957-59 collections from Whitefish Point. The weight of whitefish in the combined samples increased as the 3.2408 power of the length. The growth rate from the fastest to the slowest growing stocks ranked as follows: Whitefish Point; Dollar Settlement and Marquette (fish from the two ports reversed ranks after 3 years); Bayfield. The major differences in growth in length among the various stocks occurred during the first years of life. Beyond the fifth year the annual increments were nearly the same in all stocks. The whitefish from Whitefish Point, Dollar Settlement, and Marquette are among the fastest growing in the Great Lakes. The

Determine Age-structure of Gelatinous Zooplankton Using Optical Coherence Tomography

NASA Astrophysics Data System (ADS)

Bi, H.; Shahrestani, S.; He, Y.

2016-02-01

Gelatinous are delicate and transparent by nature, but are conspicuous in many ecosystems when in bloom. Their proliferations are a bothersome and costly nuisance and influencing important food webs and species interactions. More importantly, gelatinous zooplankton respond to climate change rapidly and understanding their upsurge needs information on their recruitment and population dynamics which in turn require their age-structure. However, ageing gelatinous zooplankton is often restricted by the fact that they shrink under unfavorable conditions. In the present study, we examine the potential of using optical coherence tomography (OCT) to age gelatinous zooplankton. OCT is a non-invasive imaging technique that uses light waves to examine 2D or 3D structure of target objects at a resolution of 3-5 µm. We were able to successfully capture both 3D and 2D images of sea nettle muscle fibers. Preliminary results on ctenophores will be discussed. Overall, this non-destructive sampling allows us to scan and capture images of mesoglea from jellyfish cultured in the lab, using the same individual repeatedly through time, documenting its growth which will provide precise measurements to construct an age key that will be applied to gelatinous zooplankton captured in the field. Coupled with information on abundance, we can start to quantify their recruitment timing and success rate.

Age and growth of alewives in the changing pelagia of Lake Ontario, 1978-1992

USGS Publications Warehouse

O'Gorman, Robert; Johannsson, Ora E.; Schneider, Clifford P.

1997-01-01

We documented the age and growth of alewives Alosa pseudoharenqus in Lake Ontario during 1978-1992 and determined if growth was affected by intraspecific competition for epilimnetic zooplankton, lake temperature, or demand of salmonine piscivores for prey. Ages of juvenile alewives were determined from scales during 1978-1983, and ages of juvenile and adult alewives were determined from otoliths during 1984-1992. Indices of abundance for alewives were calculated from spring bottom trawl catches in 1978-1992; zooplankton density and epilimnetic temperature were monitored at two stations during 1981-1991; and salmonine demand each year during 1978-1992 was calculated with a simulation model. Although we encountered 11-year-old alewives, few fish lived longer than 7 years, and most fish in the population were younger than 6 years. Mean sizes at ages 1, 2, and 3 in spring averaged 93 mm (5.1 g), 133 mm (17 g), and 149 mm (22 g), but from age 3 to age 8, mean size increased by only 5-7 mm and 2-3 g per year. Female alewives lived longer than male alewives and were always longer than male alewives at age 4 and older. Epilimnetic temperatures were suitable for rapid growth of juvenile alewives each year. Lake temperature had the potential to affect growth of adults but adult growth was not correlated with temperature suitability indices perhaps because temperature regimes differed among lake regions and alewives were mobile. Growth of alewives was not correlated with salmonine demand for prey. Competition for zooplankton among the two youngest alewife cohorts affected growth of age-1 alewives. Zooplankton density declined sharply in 1986, and should it decline again, growth of age-1 alewives will slow, unless numbers of age-0 alewives fall. Whether growth of age-1 fish declines or numbers of age-0 fish fall, the result of another decline in zooplankton density will be a reduction in the production of alewives needed to support piscivores.

The relationship between population ageing and the economic growth in Asia

NASA Astrophysics Data System (ADS)

Brendan, Lo Rick; Sek, Siok Kun

2017-08-01

Asia has witnessed robust economic growth since the 1960s. Today, emerging markets in Asia have managed to maintain rapid growth even when the world's main economies suffer from debt and banking crises. However, declining total fertility rate, increasing life expectancy, continuous change of birth and death patterns, and increasing share of old age population in the age distribution in Asia exert significant pressure on its economies. This paper analyses the relationship between population ageing and economic growth using 2 different panels of countries; one Asian and another the from the oldest countries worldwide between 1970 and 2014. The analysis is based on the Auto Regression Distributed Lag models. The MG (Mean Group) and PMG (Pooled Mean Group) estimations are applied in this analysis. The Hausman Test is conducted to decide between the MG and PMG estimators. We find that ageing will negatively affect the economy in the long run. The growing number of youths will initially have a negative effect on the economy but would eventually lead to a positive growth in the future. The old age dependency ratio has yet to have affect the Asian economy but is expected eventually to impose a negative effect as seen in the oldest nations of the world.

Age-related differences in the structural complexity of subcortical and ventricular structures.

PubMed

Madan, Christopher R; Kensinger, Elizabeth A

2017-02-01

It has been well established that the volume of several subcortical structures decreases in relation to age. Different metrics of cortical structure (e.g., volume, thickness, surface area, and gyrification) have been shown to index distinct characteristics of interindividual differences; thus, it is important to consider the relation of age to multiple structural measures. Here, we compare age-related differences in subcortical and ventricular volume to those differences revealed with a measure of structural complexity, quantified as fractal dimensionality. Across 3 large data sets, totaling nearly 900 individuals across the adult lifespan (aged 18-94 years), we found greater age-related differences in complexity than volume for the subcortical structures, particularly in the caudate and thalamus. The structural complexity of ventricular structures was not more strongly related to age than volume. These results demonstrate that considering shape-related characteristics improves sensitivity to detect age-related differences in subcortical structures. Copyright © 2016 Elsevier Inc. All rights reserved.

Neighborhood Age Structure and its Implications for Health

PubMed Central

2006-01-01

Age structure at the neighborhood level is rarely considered in contextual studies of health. However, age structure can play a critical role in shaping community life, the availability of resources, and the opportunities for social engagement—all factors that, research suggests, have direct and indirect effects on health. Age structure can be theorized as a compositional effect and as a contextual effect. In addition, the dynamic nature of age structure and the utility of a life course perspective as applied to neighborhood effects research merits attention. Four Chicago neighborhoods are summarized to illustrate how age structure varies across small space, suggesting that neighborhood age structure should be considered a key structural covariate in contextual research on health. Considering age structure implies incorporating not only meaningful cut points for important age groups (e.g., proportion 65 years and over) but attention to the shape of the distribution as well. PMID:16865558

School-age effects of the newborn individualized developmental care and assessment program for preterm infants with intrauterine growth restriction: preliminary findings.

PubMed

McAnulty, Gloria; Duffy, Frank H; Kosta, Sandra; Weisenfeld, Neil I; Warfield, Simon K; Butler, Samantha C; Alidoost, Moona; Bernstein, Jane Holmes; Robertson, Richard; Zurakowski, David; Als, Heidelise

2013-02-19

The experience in the newborn intensive care nursery results in premature infants' neurobehavioral and neurophysiological dysfunction and poorer brain structure. Preterms with severe intrauterine growth restriction are doubly jeopardized given their compromised brains. The Newborn Individualized Developmental Care and Assessment Program improved outcome at early school-age for preterms with appropriate intrauterine growth. It also showed effectiveness to nine months for preterms with intrauterine growth restriction. The current study tested effectiveness into school-age for preterms with intrauterine growth restriction regarding executive function (EF), electrophysiology (EEG) and neurostructure (MRI). Twenty-three 9-year-old former growth-restricted preterms, randomized at birth to standard care (14 controls) or to the Newborn Individualized Developmental Care and Assessment Program (9 experimentals) were assessed with standardized measures of cognition, achievement, executive function, electroencephalography, and magnetic resonance imaging. The participating children were comparable to those lost to follow-up, and the controls to the experimentals, in terms of newborn background health and demographics. All outcome measures were corrected for mother's intelligence. Analysis techniques included two-group analysis of variance and stepwise discriminate analysis for the outcome measures, Wilks' lambda and jackknifed classification to ascertain two-group classification success per and across domains; canonical correlation analysis to explore relationships among neuropsychological, electrophysiological and neurostructural domains at school-age, and from the newborn period to school-age. Controls and experimentals were comparable in age at testing, anthropometric and health parameters, and in cognitive and achievement scores. Experimentals scored better in executive function, spectral coherence, and cerebellar volumes. Furthermore, executive function, spectral coherence

Pattern, growth, and aging in aggregation kinetics of a Vicsek-like active matter model

NASA Astrophysics Data System (ADS)

Das, Subir K.

2017-01-01

Via molecular dynamics simulations, we study kinetics in a Vicsek-like phase-separating active matter model. Quantitative results, for isotropic bicontinuous pattern, are presented on the structure, growth, and aging. These are obtained via the two-point equal-time density-density correlation function, the average domain length, and the two-time density autocorrelation function. Both the correlation functions exhibit basic scaling properties, implying self-similarity in the pattern dynamics, for which the average domain size exhibits a power-law growth in time. The equal-time correlation has a short distance behavior that provides reasonable agreement between the corresponding structure factor tail and the Porod law. The autocorrelation decay is a power-law in the average domain size. Apart from these basic similarities, the overall quantitative behavior of the above-mentioned observables is found to be vastly different from those of the corresponding passive limit of the model which also undergoes phase separation. The functional forms of these have been quantified. An exceptionally rapid growth in the active system occurs due to fast coherent motion of the particles, mean-squared-displacements of which exhibit multiple scaling regimes, including a long time ballistic one.

[Age structure and genetic diversity of Homatula pycnolepis in the Nujiang River basin].

PubMed

Yue, Xing-Jian; Liu, Shao-Ping; Liu, Ming-Dian; Duan, Xin-Bin; Wang, Deng-Qiang; Chen, Da-Qing

2013-08-01

This study examined the age structure of the Loach, Homatula pycnolepis through the otolith growth rings in 204 individual specimens collected from the Xiaomengtong River of the Nujiang River (Salween River) basin in April, 2008. There were only two different age classes, 1 and 2 years of age-no 3 year olds were detected. The age structure of H. pycnolepis was simple. The complete mitochondrial DNA cytochrome b gene sequences (1140) of 80 individuals from 4 populations collected in the Nujiang River drainage were sequenced and a total of 44 variable sites were found among 4 different haplotypes. The global haplotype diversity (Hd) and nucleotide diversity (Pi) were calculated at 0.7595, 0.0151 respectively, and 0, 0 in each population, indicating a consistent lack of genetic diversity in each small population. There was obvious geographic structure in both the Nujiang River basin (NJB) group, and the Nanding River (NDR) group. The genetic distance between NJB and NDR was calculated at 0.0356, suggesting that genetic divergence resulted from long-term isolation of individual population. Such a simple age structure and a lack of genetic diversity in H. pycnolepis may potentially be due to small populations and locale fishing pressures. Accordingly, the results of this study prompt us to recommend that the NJB, NDR and Lancang River populations should be protected as three different evolutionary significant units or separated management units.

Precision of hard structures used to estimate age of mountain Whitefish (Prosopium williamsoni)

USGS Publications Warehouse

Watkins, Carson J.; Ross, Tyler J.; Hardy, Ryan S.; Quist, Michael C.

2015-01-01

The mountain whitefish (Prosopium williamsoni) is a widely distributed salmonid in western North America that has decreased in abundance over portions of its distribution due to anthropogenic disturbances. In this investigation, we examined precision of age estimates derived from scales, pectoral fin rays, and sagittal otoliths from 167 mountain whitefish. Otoliths and pectoral fin rays were mounted in epoxy and cross-sectioned before examination. Scales were pressed onto acetate slides and resulting impressions were examined. Between-reader precision (i.e., between 2 readers), between-reader variability, and reader confidence ratings were compared among hard structures. Coefficient of variation (CV) in age estimates was lowest and percentage of exact agreement (PA-0) was highest for scales (CV = 5.9; PA-0 = 70%) compared to pectoral fin rays (CV =11.0; PA-0 = 58%) and otoliths (CV = 12.3; PA-0 = 55%). Median confidence ratings were significantly different (P ≤ 0.05) among all structures, with scales having the highest median confidence. Reader confidence decreased with fish age for scales and pectoral fin rays, but reader confidence increased with fish age for otoliths. In general, age estimates were more precise and reader confidence was higher for scales compared to pectoral fin rays and otoliths. This research will help fisheries biologists in selecting the most appropriate hard structure to use for future age and growth studies on mountain whitefish. In turn, selection of the most precise hard structure will lead to better estimates of dynamic rate functions.

Effects of growth hormone and insulin-like growth factor 1 deficiency on ageing and longevity.

PubMed

Laron, Zvi

2002-01-01

Present knowledge on the effects of growth hormone (GH)/insulin-like growth hormone (IGF)1 deficiency on ageing and lifespan are reviewed. Evidence is presented that isolated GH deficiency (IGHD), multiple pituitary hormone deficiencies (MPHD) including GH, as well as primary IGE1 deficiency (GH resistance, Laron syndrome) present signs of early ageing such as thin and wrinkled skin, obesity, hyperglycemia and osteoporosis. These changes do not seem to affect the lifespan, as patients reach old age. Animal models of genetic MPHD (Ames and Snell mice) and GH receptor knockout mice (primary IGF1 deficiency) also have a statistically significant higher longevity compared to normal controls. On the contrary, mice transgenic for GH and acromegalic patients secreting large amounts of GH have premature death. In conclusion longstanding GH/IGF1 deficiency affects several parameters of the ageing process without impairing lifespan, and as shown in animal models prolongs longevity. In contrast high GH/IGF1 levels accelerate death.

Forecasting the timing of peak mandibular growth in males by using skeletal age.

PubMed

Hunter, W Stuart; Baumrind, Sheldon; Popovich, Frank; Jorgensen, Gertrud

2007-03-01

It is generally believed that the orthodontic treatment of a patient with a Class II malocclusion and a small mandible is enhanced by good growth at puberty, so that the timing of peak mandibular growth at puberty becomes of interest. To test the belief that skeletal age, whether early, average, or late, can be used to predict the timing of maximum growth of the mandible, whether early, average, or late, the predictive relationship between skeletal age and peak mandibular growth velocity (PMdV) at puberty was evaluated in 94 boys by using their longitudinal records from 4 to 18 years of age. Skeletal age was determined for each subject at ages 9 through 14 by using the method of Greulich and Pyle. At age 9, the Greulich and Pyle measurements predicted that 30 of the 94 subjects would have delayed PMdV equal to or exceeding 1 SD (of the mean age for PMdV), and 10 would have advanced PMdV equal to or exceeding 1 SD. When the actual age of PMdV was determined retrospectively from plots of annual mandibular growth increments, it was found that only 4 of the 30 in the delayed group had actually experienced delays in PMdV, and only 2 of the 10 in the advanced group had experienced accelerated PMdV. Skeletal age is not a reliable predictor of the timing of PMdV.

Modeling mangrove biomass using remote sensing based age and growth estimates

NASA Astrophysics Data System (ADS)

Lagomasino, D.; Fatoyinbo, T. E.; Feliciano, E. A.; Lee, S. K.; Trettin, C.; Mangora, M.; Rahman, M.

2016-12-01

Mangroves are highly regarded coastal forests because of their ecosystem services and high carbon storage potential. In addition, these forests can develop rapidly in locations where congenial environmental conditions and sediment supply are available. Monitoring the growth and age of developing mangrove forests is crucial for sustainable management and estimating carbon stocks. Combining imagery from radar and optical satellites (e.g., TanDEM-X and Landsat), we can estimate young mangrove growth and age at regional and continental scales. We used TanDEM-X radar interferometry for modeling canopy height in 2013 and Landsat to measure land cover change from 1990 to 2013. Annual NDVI composites were determined for each calendar year between 1990 and 2013. New land areas gained from the transition of water to vegetation were determined by the differences in annual NDVI composites and the reference year 2013. The year of the greatest NDVI difference that met the threshold criteria was used as the initial tree height (0 m). Annual canopy height growth rates were estimated by the duration between land generation times and 2013 canopy height models derived from TanDEM-X and very-high resolution optical data. In this presentation, we compare growth rates and biomass accumulation in mangrove forests at four river deltas; the Zambezi (Mozambique), Rufiji (Tanzania), Ganges (Bangladesh), and Mekong (Vietnam). The spatial patterns of growth rates coincided with characteristic successional paradigms and stream morphology, where the maximum growth rates typically occurred along prograding creek banks. Initial comparisons between height-only and growth-age biomass indicate that the latter tend to overestimate biomass for younger forest stands of similar height. Both the vertical (e.g., canopy height) and horizontal (e.g., expansion) growth rates measured from remote sensing can garner important information regarding mangrove succession and primary productivity. Continued research

"The Wisdom of Age": Perspectives on Aging and Growth among Lesbian Older Adults.

PubMed

Putney, Jennifer M; Leafmeeker, Rebecca R; Hebert, Nicholas

2016-04-01

Older lesbian-identified women are a health disparate yet resilient population about whom knowledge is limited and emerging. Among the areas in need of research are older lesbians' experiences of later life and stress-related growth. This article presents the findings from a qualitative study that investigated older lesbians' experiences of adversity and adaptation as they age. In-depth, exploratory interviews were conducted with 12 lesbian-identified women who were between the ages of 65-80. This study applied grounded theory methodology to identify respondents sources of stress and fear, their strengths and coping strategies and how those relate to each other and to their growth in later life. We advance a model of adaptive change that shows how spirituality, social support, and resistance to cultural norms help older lesbian adults cope with loss, illness, and discrimination and develop wisdom in later life. Knowledgeable practitioners can help older lesbian women identify and maintain sources of social support, explore spirituality, and facilitate continuous growth through the end of life. Social workers can advocate for services that are welcoming and affirmative so as to reduce fears of isolation and dependence associated with health decline.

Growth Mechanism of Pumpkin-Shaped Vaterite Hierarchical Structures

NASA Astrophysics Data System (ADS)

Ma, Guobin; Xu, Yifei; Wang, Mu

2015-03-01

CaCO3-based biominerals possess sophisticated hierarchical structures and promising mechanical properties. Recent researches imply that vaterite may play an important role in formation of CaCO3-based biominerals. However, as a less common polymorph of CaCO3, the growth mechanism of vaterite remains not very clear. Here we report the growth of a pumpkin-shaped vaterite hierarchical structure with a six-fold symmetrical axis and lamellar microstructure. We demonstrate that the growth is controlled by supersaturation and the intrinsic crystallographic anisotropy of vaterite. For the scenario of high supersaturation, the nucleation rate is higher than the lateral extension rate, favoring the ``double-leaf'' spherulitic growth. Meanwhile, nucleation occurs preferentially in < 11 2 0 > as determined by the crystalline structure of vaterite, modulating the grown products with a hexagonal symmetry. The results are beneficial for an in-depth understanding of the biomineralization of CaCO3. The growth mechanism may also be applicable to interpret the formation of similar hierarchical structures of other materials. The authors gratefully acknowledge the financial support from National Science Foundation of China (Grant Nos. 51172104 and 50972057) and National Key Basic Research Program of China (Grant No. 2010CB630705).

Economic consequences of population size, structure and growth.

PubMed

Lee, R

1983-01-01

There seems to be 4 major approaches to conceptualizing and modeling demographic influences on economic and social welfare. These approaches are combined in various ways to construct richer and more comprehensive models. The basic approaches are: demographic influences on household or family behavior; population growth and reproducible capital; population size and fixed factors; and population and advantages of scale. These 4 models emphasize the supply side effects of population. A few of the ways in which these theories have been combined are sketched. Neoclassical growth models often have been combined with age distributed populations of individuals (or households), assumed to pursue optimal life cycle consumption and saving. In some well known development models, neoclassical growth models for the modern sector are linked by labor markets and migration to fixed factor (land) models of the traditional (agricultural) sector. A whole series of macro simulation models for developed and developing countries was based on single sector neoclassical growth models with age distributed populations. Yet, typically the household level foundations of assumed age distribution effects were not worked out. Simon's (1977) simulation models are in a class by themselves, for they are the only models that attempt to incorporate all the kinds of effects discussed. The economic demography of the individual and family cycle, as it is affected by regimes of fertility, mortality, and nuptiality, taken as given, are considered. The examination touches on many of the purported consequences of aggregate population growth and age composition, since so many of these are based implicitly or explicitly on assertions about micro level behavior. Demographic influences on saving and consumption, on general labor supply and female labor supply, and on problems of youth and old age dependency frequently fall in this category. Finally, attention is focused specifically on macro economic issues in

Age or stage structure? A comparison of dynamic outcomes from discrete age- and stage-structured population models.

PubMed

Wikan, Arild

2012-06-01

Discrete stage-structured density-dependent and discrete age-structured density-dependent population models are considered. Regarding the former, we prove that the model at hand is permanent (i.e., that the population will neither go extinct nor exhibit explosive oscillations) and given density dependent fecundity terms we also show that species with delayed semelparous life histories tend to be more stable than species which possess precocious semelparous life histories. Moreover, our findings together with results obtained from other stage-structured models seem to illustrate a fairly general ecological principle, namely that iteroparous species are more stable than semelparous species. Our analysis of various age-structured models does not necessarily support the conclusions above. In fact, species with precocious life histories now appear to possess better stability properties than species with delayed life histories, especially in the iteroparous case. We also show that there are dynamical outcomes from semelparous age-structured models which we are not able to capture in corresponding stage-structured cases. Finally, both age- and stage-structured population models may generate periodic dynamics of low period (either exact or approximate). The important prerequisite is to assume density-dependent survival probabilities.

Growth hormone, insulin and aging: The benefits of endocrine defects

PubMed Central

Bartke, Andrzej

2012-01-01

Longevity of mice can be increased by spontaneous or experimentally induced mutations that interfere with the biosynthesis or actions of growth hormone (GH), insulin-like growth factor 1 (IGF-1), or insulin in the adipose tissue. The effects of GH resistance and deficiency of GH (along with thyrotropin and prolactin) on aging and lifespan are the most pronounced and best established of these mutations. Potential mechanisms linking these endocrine deficits with delayed aging and extended longevity include increased stress resistance, alterations in insulin and mammalian target of rapamycin (mTOR) signaling and metabolic adjustments. Physiological relationships deduced from the extreme phenotypes of long-lived mouse mutants appear to apply broadly, encompassing genetically normal (“wild-type”) mice and other mammalian species. The role of GH in the control of human aging continues to be hotly debated, but recent data indicate that reduced somatotropic signaling provides protection from cancer and other age-related diseases and may promote old age survival. PMID:20851173

Structural growth trajectories and rates of change in the first 3 months of infant brain development.

PubMed

Holland, Dominic; Chang, Linda; Ernst, Thomas M; Curran, Megan; Buchthal, Steven D; Alicata, Daniel; Skranes, Jon; Johansen, Heather; Hernandez, Antonette; Yamakawa, Robyn; Kuperman, Joshua M; Dale, Anders M

2014-10-01

The very early postnatal period witnesses extraordinary rates of growth, but structural brain development in this period has largely not been explored longitudinally. Such assessment may be key in detecting and treating the earliest signs of neurodevelopmental disorders. To assess structural growth trajectories and rates of change in the whole brain and regions of interest in infants during the first 3 months after birth. Serial structural T1-weighted and/or T2-weighted magnetic resonance images were obtained for 211 time points from 87 healthy term-born or term-equivalent preterm-born infants, aged 2 to 90 days, between October 5, 2007, and June 12, 2013. We segmented whole-brain and multiple subcortical regions of interest using a novel application of Bayesian-based methods. We modeled growth and rate of growth trajectories nonparametrically and assessed left-right asymmetries and sexual dimorphisms. Whole-brain volume at birth was approximately one-third of healthy elderly brain volume, and did not differ significantly between male and female infants (347 388 mm3 and 335 509 mm3, respectively, P = .12). The growth rate was approximately 1%/d, slowing to 0.4%/d by the end of the first 3 months, when the brain reached just more than half of elderly adult brain volume. Overall growth in the first 90 days was 64%. There was a significant age-by-sex effect leading to widening separation in brain sizes with age between male and female infants (with male infants growing faster than females by 200.4 mm3/d, SE = 67.2, P = .003). Longer gestation was associated with larger brain size (2215 mm3/d, SE = 284, P = 4×10-13). The expected brain size of an infant born one week earlier than average was 5% smaller than average; at 90 days it will not have caught up, being 2% smaller than average. The cerebellum grew at the highest rate, more than doubling in 90 days, and the hippocampus grew at the slowest rate, increasing by 47% in 90 days. There was left

Structural Growth Trajectories and Rates of Change in the First 3 Months of Infant Brain Development

PubMed Central

Holland, Dominic; Chang, Linda; Ernst, Thomas M.; Curran, Megan; Buchthal, Steven D.; Alicata, Daniel; Skranes, Jon; Johansen, Heather; Hernandez, Antonette; Yamakawa, Robyn; Kuperman, Joshua M.; Dale, Anders M.

2016-01-01

IMPORTANCE The very early postnatal period witnesses extraordinary rates of growth, but structural brain development in this period has largely not been explored longitudinally. Such assessment may be key in detecting and treating the earliest signs of neurodevelopmental disorders. OBJECTIVE To assess structural growth trajectories and rates of change in the whole brain and regions of interest in infants during the first 3 months after birth. DESIGN, SETTING, AND PARTICIPANTS Serial structural T1-weighted and/or T2-weighted magnetic resonance images were obtained for 211 time points from 87 healthy term-born or term-equivalent preterm-born infants, aged 2 to 90 days, between October 5, 2007, and June 12, 2013. MAIN OUTCOMES AND MEASURES We segmented whole-brain and multiple subcortical regions of interest using a novel application of Bayesian-based methods. We modeled growth and rate of growth trajectories nonparametrically and assessed left-right asymmetries and sexual dimorphisms. RESULTS Whole-brain volume at birth was approximately one-third of healthy elderly brain volume, and did not differ significantly between male and female infants (347 388 mm3 and 335 509 mm3, respectively, P = .12). The growth rate was approximately 1%/d, slowing to 0.4%/d by the end of the first 3 months, when the brain reached just more than half of elderly adult brain volume. Overall growth in the first 90 days was 64%. There was a significant age-by-sex effect leading to widening separation in brain sizes with age between male and female infants (with male infants growing faster than females by 200.4 mm3/d, SE = 67.2, P = .003). Longer gestation was associated with larger brain size (2215 mm3/d, SE = 284, P = 4×10−13). The expected brain size of an infant born one week earlier than average was 5% smaller than average; at 90 days it will not have caught up, being 2% smaller than average. The cerebellum grew at the highest rate, more than doubling in 90 days, and the hippocampus

Ultrasonography in determining pubertal growth and bone age.

PubMed

Torenek Ağırman, Kubra; Bilge, Osman Murat; Miloğlu, Özkan

2018-05-02

The purpose of this study is to evaluate the compatibility of ultrasonographic data with hand-wrist radiographs taken to determine the extent of pubertal growth and bone age in patients and investigate the usability of ionizing radiation-free ultrasonography instead of conventional radiography. In this study, a total of 120 children from 10 to 17 years old (mean age was 168 months ± 27.5 months) were treated with routine radiographs before orthodontic treatment, and ultrasonographic imaging was performed on the wrists the same day. Researchers examined the phalanges, sesamoid bone, and radial bone distal epiphysis-diaphysis comparatively in each patient by both imaging methods and statistical evaluation. There was no statistically significant difference between conventional radiography and ultrasonography values at 13 points except for PP1 (proximal phalanges of the first finger), PP2 (proximal phalanges of the second finger), and radial epiphysis (p > 0.05). PP1, PP2, and radial epiphysis showed a statistically significant difference (p < 0.05). The CBA (bone age obtained from conventional radiographs) of the females was found to be larger than their CA (chronological age) and their UBA (ultrasonographic bone age). For males; the means of the CBA, UBA and CA values close to each other. In females and males; there was a strong correlation between the CA, the UBA and the CBA (p < 0.01). Ultrasonography gives detailed information about epiphyseal diaphysis relations. It can be used as an alternative to conventional radiography in the detection of bone age and pubertal growth, owing to the absence of ionizing radiation.

The immune-endocrine loop during aging: role of growth hormone and insulin-like growth factor-I.

PubMed

Burgess, W; Liu, Q; Zhou, J; Tang, Q; Ozawa, A; VanHoy, R; Arkins, S; Dantzer, R; Kelley, K W

1999-01-01

Why a primary lymphoid organ such as the thymus involutes during aging remains a fundamental question in immunology. Aging is associated with a decrease in plasma growth hormone (somatotropin) and IGF-I, and this somatopause of aging suggests a connection between the neuroendocrine and immune systems. Several investigators have demonstrated that treatment with either growth hormone or IGF-I restores architecture of the involuted thymus gland by reversing the loss of immature cortical thymocytes and preventing the decline in thymulin synthesis that occurs in old or GH-deficient animals and humans. The proliferation, differentiation and functions of other components of the immune system, including T and B cells, macrophages and neutrophils, also demonstrate age-associated decrements that can be restored by IGF-I. Knowledge of the mechanism by which cytokines and hormones influence hematopoietic cells is critical to improving the health of aged individuals. Our laboratory has recently demonstrated that IGF-I prevents apoptosis in promyeloid cells, which subsequently permits these cells to differentiate into neutrophils. We also demonstrated that IL-4 acts much like IGF-I to promote survival of promyeloid cells and to activate the enzyme phosphatidylinositol 3'-kinase (PI 3-kinase). However, the receptors for IGF-I and IL-4 are completely different, with the intracellular beta chains of the IGF receptor possessing intrinsic tyrosine kinase activity and the alpha and gammac subunit of the heterodimeric IL-4 receptor utilizing the Janus kinase family of nonreceptor protein kinases to tyrosine phosphorylate downstream targets. Both receptors share many of the components of the PI 3-kinase signal transduction pathway, converging at the level of insulin receptor substrate-1 or insulin receptor subtrate-2 (formally known as 4PS, or IL-4 Phosphorylated Substrate). Our investigations with IGF-I and IL-4 suggest that PI 3-kinase inhibits apoptosis by maintaining high levels of

Individual tree growth models for natural even-aged shortleaf pine

Treesearch

Chakra B. Budhathoki; Thomas B. Lynch; James M. Guldin

2006-01-01

Shortleaf pine (Pinus echinata Mill.) measurements were available from permanent plots established in even-aged stands of the Ouachita Mountains for studying growth. Annual basal area growth was modeled with a least-squares nonlinear regression method utilizing three measurements. The analysis showed that the parameter estimates were in agreement...

Parental age and child growth and development: child health check-up data.

PubMed

Iwayama, Mariko; Kira, Ryutaro; Kinukawa, Naoko; Sakai, Yasunari; Torisu, Hiroyuki; Sanefuji, Masafumi; Ishizaki, Yoshito; Nose, Yoshiaki; Matsumoto, Toshimichi; Hara, Toshiro

2011-10-01

The aim of the present study was to determine whether parental age has any influence on child health. Well-baby check-up data at 1 month and at 12 months of age were used. The trends of parental age in association with growth measurements, incidence of physical and developmental abnormalities, occurrence of low birthweight, and maternal history of spontaneous abortion were analyzed. Associations between increasing paternal age and incidence of psychomotor developmental delay at 12 months, increasing paternal and maternal age and increasing birthweight, and increasing parental age and higher incidence of history of spontaneous abortion were found. The incidence of low-birthweight infants was significantly decreased with increasing paternal age. Not only increasing maternal age but also increasing paternal age have influences on child development and growth in the general population. © 2011 The Authors. Pediatrics International © 2011 Japan Pediatric Society.

Mature and old-growth riparian forests: structure, dynamics, and effects on Adirondack stream habitats.

PubMed

Keeton, William S; Kraft, Clifford E; Warren, Dana R

2007-04-01

Riparian forests regulate linkages between terrestrial and aquatic ecosystems, yet relationships among riparian forest development, stand structure, and stream habitats are poorly understood in many temperate deciduous forest systems. Our research has (1) described structural attributes associated with old-growth riparian forests and (2) assessed linkages between these characteristics and in-stream habitat structure. The 19 study sites were located along predominantly first- and second-order streams in northern hardwood-conifer forests in the Adirondack Mountains of New York (U.S.A.). Sites were classified as mature forest (6 sites), mature with remnant old-growth trees (3 sites), and old-growth (10 sites). Forest-structure attributes were measured over stream channels and at varying distances from each bank. In-stream habitat features such as large woody debris (LWD), pools, and boulders were measured in each stream reach. Forest structure was examined in relation to stand age using multivariate techniques, ANOVA, and linear regression. We investigated linkages between forest structure and stream characteristics using similar methods, preceded by information-theoretic modeling (AIC). Old-growth riparian forest structure is more complex than that found in mature forests and exhibits significantly greater accumulations of aboveground tree biomass, both living and dead. In-stream LWD volumes were significantly (alpha = 0.05) greater at old-growth sites (200 m3/ha) compared to mature sites (34 m3/ha) and were strongly related to the basal area of adjacent forests. In-stream large-log densities correlated strongly with debris-dam densities. AIC models that included large-log density, debris-dam density, boulder density, and bankfull width had the most support for predicting pool density. There were higher proportions of LWD-formed pools relative to boulder-formed pools at old-growth sites as compared to mature sites. Old-growth riparian forests provide in

An Age-Structured Extension to the Vectorial Capacity Model

PubMed Central

Novoseltsev, Vasiliy N.; Michalski, Anatoli I.; Novoseltseva, Janna A.; Yashin, Anatoliy I.; Carey, James R.; Ellis, Alicia M.

2012-01-01

Background Vectorial capacity and the basic reproductive number (R0) have been instrumental in structuring thinking about vector-borne pathogen transmission and how best to prevent the diseases they cause. One of the more important simplifying assumptions of these models is age-independent vector mortality. A growing body of evidence indicates that insect vectors exhibit age-dependent mortality, which can have strong and varied affects on pathogen transmission dynamics and strategies for disease prevention. Methodology/Principal Findings Based on survival analysis we derived new equations for vectorial capacity and R0 that are valid for any pattern of age-dependent (or age–independent) vector mortality and explore the behavior of the models across various mortality patterns. The framework we present (1) lays the groundwork for an extension and refinement of the vectorial capacity paradigm by introducing an age-structured extension to the model, (2) encourages further research on the actuarial dynamics of vectors in particular and the relationship of vector mortality to pathogen transmission in general, and (3) provides a detailed quantitative basis for understanding the relative impact of reductions in vector longevity compared to other vector-borne disease prevention strategies. Conclusions/Significance Accounting for age-dependent vector mortality in estimates of vectorial capacity and R0 was most important when (1) vector densities are relatively low and the pattern of mortality can determine whether pathogen transmission will persist; i.e., determines whether R0 is above or below 1, (2) vector population growth rate is relatively low and there are complex interactions between birth and death that differ fundamentally from birth-death relationships with age-independent mortality, and (3) the vector exhibits complex patterns of age-dependent mortality and R0∼1. A limiting factor in the construction and evaluation of new age-dependent mortality models is the

School-age effects of the newborn individualized developmental care and assessment program for preterm infants with intrauterine growth restriction: preliminary findings

PubMed Central

2013-01-01

Background The experience in the newborn intensive care nursery results in premature infants’ neurobehavioral and neurophysiological dysfunction and poorer brain structure. Preterms with severe intrauterine growth restriction are doubly jeopardized given their compromised brains. The Newborn Individualized Developmental Care and Assessment Program improved outcome at early school-age for preterms with appropriate intrauterine growth. It also showed effectiveness to nine months for preterms with intrauterine growth restriction. The current study tested effectiveness into school-age for preterms with intrauterine growth restriction regarding executive function (EF), electrophysiology (EEG) and neurostructure (MRI). Methods Twenty-three 9-year-old former growth-restricted preterms, randomized at birth to standard care (14 controls) or to the Newborn Individualized Developmental Care and Assessment Program (9 experimentals) were assessed with standardized measures of cognition, achievement, executive function, electroencephalography, and magnetic resonance imaging. The participating children were comparable to those lost to follow-up, and the controls to the experimentals, in terms of newborn background health and demographics. All outcome measures were corrected for mother’s intelligence. Analysis techniques included two-group analysis of variance and stepwise discriminate analysis for the outcome measures, Wilks’ lambda and jackknifed classification to ascertain two-group classification success per and across domains; canonical correlation analysis to explore relationships among neuropsychological, electrophysiological and neurostructural domains at school-age, and from the newborn period to school-age. Results Controls and experimentals were comparable in age at testing, anthropometric and health parameters, and in cognitive and achievement scores. Experimentals scored better in executive function, spectral coherence, and cerebellar volumes. Furthermore

Growth pattern from birth to adulthood in African pygmies of known age.

PubMed

Rozzi, Fernando V Ramirez; Koudou, Yves; Froment, Alain; Le Bouc, Yves; Botton, Jérémie

2015-07-28

The African pygmy phenotype stems from genetic foundations and is considered to be the product of a disturbance in the growth hormone-insulin-like growth factor (GH-IGF) axis. However, when and how the pygmy phenotype is acquired during growth remains unknown. Here we describe growth patterns in Baka pygmies based on two longitudinal studies of individuals of known age, from the time of birth to the age of 25 years. Body size at birth among the Baka is within standard limits, but their growth rate slows significantly during the first two years of life. It then more or less follows the standard pattern, with a growth spurt at adolescence. Their life history variables do not allow the Baka to be distinguished from other populations. Therefore, the pygmy phenotype in the Baka is the result of a change in growth that occurs during infancy, which differentiates them from East African pygmies revealing convergent evolution.

Growth pattern from birth to adulthood in African pygmies of known age

PubMed Central

Rozzi, Fernando V. Ramirez; Koudou, Yves; Froment, Alain; Le Bouc, Yves; Botton, Jérémie

2015-01-01

The African pygmy phenotype stems from genetic foundations and is considered to be the product of a disturbance in the growth hormone–insulin-like growth factor (GH–IGF) axis. However, when and how the pygmy phenotype is acquired during growth remains unknown. Here we describe growth patterns in Baka pygmies based on two longitudinal studies of individuals of known age, from the time of birth to the age of 25 years. Body size at birth among the Baka is within standard limits, but their growth rate slows significantly during the first two years of life. It then more or less follows the standard pattern, with a growth spurt at adolescence. Their life history variables do not allow the Baka to be distinguished from other populations. Therefore, the pygmy phenotype in the Baka is the result of a change in growth that occurs during infancy, which differentiates them from East African pygmies revealing convergent evolution. PMID:26218408

Age and growth parameters of shark-like batoids.

PubMed

White, J; Simpfendorfer, C A; Tobin, A J; Heupel, M R

2014-05-01

Estimates of life-history parameters were made for shark-like batoids of conservation concern Rhynchobatus spp. (Rhynchobatus australiae, Rhynchobatus laevis and Rhynchobatus palpebratus) and Glaucostegus typus using vertebral ageing. The sigmoid growth functions, Gompertz and logistic, best described the growth of Rhynchobatus spp. and G. typus, providing the best statistical fit and most biologically appropriate parameters. The two-parameter logistic was the preferred model for Rhynchobatus spp. with growth parameter estimates (both sexes combined) L(∞) = 2045 mm stretch total length, LST and k = 0·41 year⁻¹. The same model was also preferred for G. typus with growth parameter estimates (both sexes combined) L∞  = 2770 mm LST and k = 0·30 year⁻¹. Annual growth-band deposition could not be excluded in Rhynchobatus spp. using mark-recaptured individuals. Although morphologically similar G. typus and Rhynchobatus spp. have differing life histories, with G. typus longer lived, slower growing and attaining a larger maximum size. © 2014 The Fisheries Society of the British Isles.

Fatigue-Crack-Growth Structural Analysis

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.

1986-01-01

Elastic and plastic deformations calculated under variety of loading conditions. Prediction of fatigue-crack-growth lives made with FatigueCrack-Growth Structural Analysis (FASTRAN) computer program. As cyclic loads are applied to initial crack configuration, FASTRAN predicts crack length and other parameters until complete break occurs. Loads are tensile or compressive and of variable or constant amplitude. FASTRAN incorporates linear-elastic fracture mechanics with modifications of load-interaction effects caused by crack closure. FASTRAN considered research tool, because of lengthy calculation times. FASTRAN written in FORTRAN IV for batch execution.

Nonlinear structural crack growth monitoring

DOEpatents

Welch, Donald E.; Hively, Lee M.; Holdaway, Ray F.

2002-01-01

A method and apparatus are provided for the detection, through nonlinear manipulation of data, of an indicator of imminent failure due to crack growth in structural elements. The method is a process of determining energy consumption due to crack growth and correlating the energy consumption with physical phenomena indicative of a failure event. The apparatus includes sensors for sensing physical data factors, processors or the like for computing a relationship between the physical data factors and phenomena indicative of the failure event, and apparatus for providing notification of the characteristics and extent of such phenomena.

Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

USGS Publications Warehouse

Silver, Emily J.; D'Amato, Anthony W.; Fraver, Shawn; Palik, Brian J.; Bradford, John B.

2013-01-01

The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types. Moreover, the effectiveness of approaches recommended for restoring old-growth structural conditions to managed forests, such as the application of extended rotation forestry, has been little studied. This study uses several long-term datasets from old growth, extended rotation, and unmanaged second growth Pinus resinosa (red pine) forests in northern Minnesota, USA, to quantify the range of variation in structural conditions for this forest type and to evaluate the effectiveness of extended rotation forestry at promoting the development of late-successional structural conditions. Long-term tree population data from permanent plots for one of the old-growth stands and the extended rotation stands (87 and 61 years, respectively) also allowed for an examination of the long-term structural dynamics of these systems. Old-growth forests were more structurally complex than unmanaged second-growth and extended rotation red pine stands, due in large part to the significantly higher volumes of coarse woody debris (70.7 vs. 11.5 and 4.7 m3/ha, respectively) and higher snag basal area (6.9 vs. 2.9 and 0.5 m2/ha, respectively). In addition, old-growth forests, although red pine-dominated, contained a greater abundance of other species, including Pinus strobus, Abies balsamea, and Picea glauca relative to the other stand types examined. These differences between stand types largely reflect historic gap-scale disturbances within the old-growth systems and their corresponding structural and compositional legacies. Nonetheless, extended rotation thinning treatments, by accelerating advancement to larger tree diameter

Spontaneous growth in growth hormone deficiency from birth until 7 years of age: development of disease-specific growth curves.

PubMed

Mayer, M; Schmitt, K; Kapelari, K; Frisch, H; Köstl, G; Voigt, M

2010-01-01

Little is known about spontaneous growth of growth hormone (GH)-deficient children during infancy and childhood. Retrospectively, we calculated disease-specific pretreatment percentiles for height, weight, BMI and growth velocity of 113 GH-deficient boys and 41 GH-deficient girls from birth until 7 years of age, by mean and standard deviation. Infants with idiopathic GH deficiency (GHD) grow in disease-specific percentile channels. There is a significant difference in length and weight from birth onward compared to regional reference (p<0.001). Boys' birth length was 48.7+/-2.9 cm (p<0.001; -1.31+/-1.11 SDS), birth weight was 3.09+/-0.61 kg (p<0.01; -0.92+/-1.19 SDS), and BMI at birth was 12.9+/-1.7. Girls' birth length was 48.1+/-3.4 cm (p<0.05; -1.17+/-1.51 SDS), birth weight was 2.92+/-0.60 kg (p=0.05; -1.08+/-1.19 SDS), and BMI at birth was 12.6+/-2.2. There was a continuous loss of growth velocity, despite a wide variance in the first years, so height deficit became more evident with increasing age. GHD is a congenital disease no matter when height deficit becomes clinically evident, because GH-deficient children grow in disease-specific percentile channels with a highly significantly reduced length and weight, which demonstrates that GH is essential for adequate growth in infancy and early childhood. Copyright (c) 2010 S. Karger AG, Basel.

Earlier Mother's Age at Menarche Predicts Rapid Infancy Growth and Childhood Obesity

PubMed Central

Ong, Ken K; Northstone, Kate; Wells, Jonathan CK; Rubin, Carol; Ness, Andy R; Golding, Jean; Dunger, David B

2007-01-01

Background Early menarche tends to be preceded by rapid infancy weight gain and is associated with increased childhood and adult obesity risk. As age at menarche is a heritable trait, we hypothesised that age at menarche in the mother may in turn predict her children's early growth and obesity risk. Methods and Findings We tested associations between mother's age at menarche, mother's adult body size and obesity risk, and her children's growth and obesity risk in 6,009 children from the UK population-based Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort who had growth and fat mass at age 9 y measured by dual-energy X-ray absorptiometry. A subgroup of 914 children also had detailed infancy and childhood growth data. In the mothers, earlier menarche was associated with shorter adult height (by 0.64 cm/y), increased weight (0.92 kg/y), and body mass index (BMI, 0.51 kg/m2/y; all p < 0.001). In contrast, in her children, earlier mother's menarche predicted taller height at 9 y (by 0.41 cm/y) and greater weight (0.80 kg/y), BMI (0.29 kg/m2/y), and fat mass index (0.22 kg/m2/year; all p < 0.001). Children in the earliest mother's menarche quintile (≤11 y) were more obese than the oldest quintile (≥15 y) (OR, 2.15, 95% CI 1.46 to 3.17; p < 0.001, adjusted for mother's education and BMI). In the subgroup, children in the earliest quintile showed faster gains in weight (p < 0.001) and height (p < 0.001) only from birth to 2 y, but not from 2 to 9 y (p = 0.3–0.8). Conclusions Earlier age at menarche may be a transgenerational marker of a faster growth tempo, characterised by rapid weight gain and growth, particularly during infancy, and leading to taller childhood stature, but likely earlier maturation and therefore shorter adult stature. This growth pattern confers increased childhood and adult obesity risks. PMID:17455989

Age determination in manatees using growth-layer-group counts in bone

USGS Publications Warehouse

Marmontel, M.; O'Shea, T.J.; Kochman, H.I.; Humphrey, S.R.

1996-01-01

Growth layers were observed in histological preparations of bones of known-age, known minimum-age, and tetracycline-marked free-ranging and captive Florida manatees (Trichechus manatus latirostris), substantiating earlier preliminary findings of other studies. Detailed analysis of 17 new case histories showed that growth-layer group (GLG) counts in the periotic bone were consistent with known age, or time since tetracycline administration, but were less reliable in other bones. GLG counts were also made in periotic bones of 1,196 Florida manatees of unknown age found dead from 1974 through 1991. These counts were conducted in order to assess variability and to determine relationships among estimated age, size, sex, and degree of bone resorption. Resorption can interfere with accuracy of GLG counts. This effect does not occur until ages greater than about 15 yr and body lengths greater than 300 cm are attained. GLGs were also observed in periotic bones of Antillean manatees (Trichechus manatus manatus) but were not validated against known-age specimens. Use of GLG counts in the periotic bone is suitable for application to studies of population dynamics and other age-related aspects of manatee biology.

The influence of age and exercise modality on growth hormone bioactivity in women.

PubMed

Gordon, Scott E; Kraemer, William J; Looney, David P; Flanagan, Shawn D; Comstock, Brett A; Hymer, Wesley C

2014-01-01

Prior research has indicated that the loss of skeletal muscle mass and bone mineral density observed with aging is related to the prominent age-related decline in the concentration of serum growth hormone (GH). However, there is limited data on the effects of aging on GH responses to acute bouts of heavy resistance exercise (HRE) and aerobic exercise (AE). The present investigation examined the effects of a HRE protocol and an AE protocol on immunoreactive GH (IGH) and bioactive GH (BGH) in active young and old women. Older women had a diminished serum IGH response to both the HRE and AE protocols compared to the younger women, however a similar response was not observed in serum BGH. Additionally, the HRE protocol elicited a greater BGH response than the AE protocol exclusively in the younger group. Regardless of exercise mode, aging induces an increase in growth hormone polymerization that specifically results in a loss of serum growth hormone immunoreactivity without a concurrent loss of serum growth hormone bioactivity. The greater BGH response to the HRE protocol found in the younger group can be attributed to an unknown serum factor of molecular weight between 30 and 55kD that either potentiated growth hormone bioactivity in response to HRE or inhibited growth hormone bioactivity in response to AE. Copyright © 2014 Elsevier Ltd. All rights reserved.

Postnatal Brain Growth Assessed by Sequential Cranial Ultrasonography in Infants Born <30 Weeks' Gestational Age.

PubMed

Cuzzilla, R; Spittle, A J; Lee, K J; Rogerson, S; Cowan, F M; Doyle, L W; Cheong, J L Y

2018-06-01

Brain growth in the early postnatal period following preterm birth has not been well described. This study of infants born at <30 weeks' gestational age and without major brain injury aimed to accomplish the following: 1) assess the reproducibility of linear measures made from cranial ultrasonography, 2) evaluate brain growth using sequential cranial ultrasonography linear measures from birth to term-equivalent age, and 3) explore perinatal predictors of postnatal brain growth. Participants comprised 144 infants born at <30 weeks' gestational age at a single center between January 2011 and December 2013. Infants with major brain injury seen on cranial ultrasonography or congenital or chromosomal abnormalities were excluded. Brain tissue and fluid spaces were measured from cranial ultrasonography performed as part of routine clinical care. Brain growth was assessed in 3 time intervals: <7, 7-27, and >27 days' postnatal age. Data were analyzed using intraclass correlation coefficients and mixed-effects regression. A total of 429 scans were assessed for 144 infants. Several linear measures showed excellent reproducibility. All measures of brain tissue increased with postnatal age, except for the biparietal diameter, which decreased within the first postnatal week and increased thereafter. Gestational age of ≥28 weeks at birth was associated with slower growth of the biparietal diameter and ventricular width compared with gestational age of <28 weeks. Postnatal corticosteroid administration was associated with slower growth of the corpus callosum length, transcerebellar diameter, and vermis height. Sepsis and necrotizing enterocolitis were associated with slower growth of the transcerebellar diameter. Postnatal brain growth in infants born at <30 weeks' gestational age can be evaluated using sequential linear measures made from routine cranial ultrasonography and is associated with perinatal predictors of long-term development. © 2018 by American Journal of

Consumptive and nonconsumptive effects of cannibalism in fluctuating age-structured populations.

PubMed

Wissinger, Scott A; Whiteman, Howard H; Denoël, Mathieu; Mumford, Miranda L; Aubee, Catherine B

2010-02-01

Theory and empirical studies suggest that cannibalism in age-structured populations can regulate recruitment depending on the intensity of intraspecific competition between cannibals and victims and the nature of the cannibalism window, i.e., which size classes interact as cannibals and victims. Here we report on a series of experiments that quantify that window for age-structured populations of salamander larvae and paedomorphic adults. We determined body size limits on cannibalism in microcosms and then the consumptive and nonconsumptive (injuries, foraging and activity, diet, growth) effects on victims in mesocosms with seminatural levels of habitat complexity and alternative prey. We found that cannibalism by the largest size classes (paedomorphs and > or = age 3+ yr larvae) occurs mainly on young-of-the-year (YOY) victims. Surviving YOY and other small larvae had increased injuries, reduced activity levels, and reduced growth rates in the presence of cannibals. Data on YOY survival in an experiment in which we manipulated the density of paedomorphs combined with historical data on the number of cannibals in natural populations indicate that dominant cohorts of paedomorphs can cause observed recruitment failures. Dietary data indicate that ontogenetic shifts in diet should preclude strong intraspecific competition between YOY and cannibals in this species. Thus our results are consistent with previous empirical and theoretical work that suggests that recruitment regulation by cannibalism is most likely when YOY are vulnerable to cannibalism but have low dietary overlap with cannibals. Understanding the role of cannibalism in regulating recruitment in salamander populations is timely, given the widespread occurrences of amphibian decline. Previous studies have focused on extrinsic (including anthropogenic) factors that affect amphibian population dynamics, whereas the data presented here combined with long-term field observations suggest the potential for

Aging, Maturation and Growth of Sauropodomorph Dinosaurs as Deduced from Growth Curves Using Long Bone Histological Data: An Assessment of Methodological Constraints and Solutions

PubMed Central

Griebeler, Eva Maria; Klein, Nicole; Sander, P. Martin

2013-01-01

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 mammals, but

Aging, Maturation and Growth of Sauropodomorph Dinosaurs as Deduced from Growth Curves Using Long Bone Histological Data: An Assessment of Methodological Constraints and Solutions.

PubMed

Griebeler, Eva Maria; Klein, Nicole; Sander, P Martin

2013-01-01

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 mammals, but

The height-, weight-, and BMI-for-age of Polish school-aged children and adolescents relative to international and local growth references.

PubMed

Kulaga, Zbigniew; Litwin, Mieczysław; Tkaczyk, Marcin; Rózdzyńska, Agnieszka; Barwicka, Katarzyna; Grajda, Aneta; Swiader, Anna; Gurzkowska, Beata; Napieralska, Ewelina; Pan, Huiqi

2010-03-04

The growth of children is an indicator of health and society's wellbeing. Growth references are useful in monitoring a child's growth, which is a very important part of child care. Poland's growth references are not updated regularly. Although several growth reference ranges have been developed in Poland over recent years, sampling was restricted to urban populations of major cities. The aim of this study was to assess how well Polish children match with, or diverge from, regional charts and to compare them with international growth references. Four Polish and two international (WHO 2007 and USCDC2000) growth references were used to calculate the height, weight and BMI z-scores in a recent, large, population-representative sample of school-aged children and adolescents in Poland. The distributions of z-scores were analysed with descriptive and inferential statistical methods. Mean height z-scores calculated with the use of the WHO 2007 and USCDC2000 references were positive and significantly different from zero over the entire age range. The mean height z-score was closest to zero in the Poznan reference for boys (0.05) and Warszawa reference for girls (0.01). Median weight z-scores were positive under all weight references over the entire age range with only the exception of 18-year-old girls' weight z-score calculated relative to USCDC2000. Median BMI z-scores were positive in males in early childhood, decreasing with age. In the case of girls, the median BMI z-score calculated using WHO 2007 and USCDC2000 was close to zero in early childhood, decreased in adolescents and reached minimum values at age 18 years. Median BMI z-scores calculated with the use of the Lodz reference fluctuated between 0.05 and 0.2 over the studied age range. In this contemporary sample of Polish school-aged children, distributions of height, weight and BMI differed from those of children from the international growth references. These differences should be considered when using the

The height-, weight-, and BMI-for-age of Polish school-aged children and adolescents relative to international and local growth references

PubMed Central

2010-01-01

Background The growth of children is an indicator of health and society's wellbeing. Growth references are useful in monitoring a child's growth, which is a very important part of child care. Poland's growth references are not updated regularly. Although several growth reference ranges have been developed in Poland over recent years, sampling was restricted to urban populations of major cities. The aim of this study was to assess how well Polish children match with, or diverge from, regional charts and to compare them with international growth references. Methods Four Polish and two international (WHO 2007 and USCDC2000) growth references were used to calculate the height, weight and BMI z-scores in a recent, large, population-representative sample of school-aged children and adolescents in Poland. The distributions of z-scores were analysed with descriptive and inferential statistical methods. Results Mean height z-scores calculated with the use of the WHO 2007 and USCDC2000 references were positive and significantly different from zero over the entire age range. The mean height z-score was closest to zero in the Poznan reference for boys (0.05) and Warszawa reference for girls (0.01). Median weight z-scores were positive under all weight references over the entire age range with only the exception of 18-year-old girls' weight z-score calculated relative to USCDC2000. Median BMI z-scores were positive in males in early childhood, decreasing with age. In the case of girls, the median BMI z-score calculated using WHO 2007 and USCDC2000 was close to zero in early childhood, decreased in adolescents and reached minimum values at age 18 years. Median BMI z-scores calculated with the use of the Lodz reference fluctuated between 0.05 and 0.2 over the studied age range. Conclusions In this contemporary sample of Polish school-aged children, distributions of height, weight and BMI differed from those of children from the international growth references. These differences

Structural technology challenges for evolutionary growth of Space Station Freedom

NASA Technical Reports Server (NTRS)

Doiron, Harold H.

1990-01-01

A proposed evolutionary growth scenario for Space Station Freedom was defined recently by a NASA task force created to study requirements for a Human Exploration Initiative. The study was an initial response to President Bush's July 20, 1989 proposal to begin a long range program of human exploration of space including a permanently manned lunar base and a manned mission to Mars. This growth scenario evolves Freedom into a critical transportation node to support lunar and Mars missions. The growth scenario begins with the Assembly Complete configuration and adds structure, power, and facilities to support a Lunar Transfer Vehicle (LTV) verification flight. Evolutionary growth continues to support expendable, then reusable LTV operations, and finally, LTV and Mars Transfer Vehicle (MTV) operations. The significant structural growth and additional operations creating new loading conditions will present new technological and structural design challenges in addition to the considerable technology requirements of the baseline Space Station Freedom program. Several structural design and technology issues of the baseline program are reviewed and related technology development required by the growth scenario is identified.

Spaceflight and age affect tibial epiphyseal growth plate histomorphometry

NASA Technical Reports Server (NTRS)

Montufar-Solis, Dina; Duke, Pauline J.; Durnova, G.

1992-01-01

Growth plate histomorphometry of rats flown aboard the Soviet biosatellite Cosmos 2044, a 14-day spaceflight, was compared with that of control groups. In growth plates of flight animals, there was a significant increase in cell number per column and height of the proliferative zone and a reduction in height and cell number in the hypertrophy/calcification zone. No significant differences were found in matrix organization at the ultrastructural level of flight animals, indicating that although spacefligfht continues to affect bone growth of 15-wk-old rats, extracellular matrix is not altered in the same manner as seen previously in younger animals. All groups showed growth plate characteristics attributed to aging: lack of calcification zone, reduced hypertrophy zone, and unraveling of collagen fibrils. Tail-suspended controls did not differ from other controls in any of the parameters measured. The results suggest that growth plates of older rats are less responsive to unloading by spaceflight or suspension than those of younger rats and provide new evidence about the modifying effect of spaceflight on the growth plate.

Growth, population structure, and reproduction of western pond turtles (Actinemys marmorata) on the central coast of California

USGS Publications Warehouse

Germano, D.J.; Rathbun, G.B.

2008-01-01

We studied the population structure and growth of western pond turtles (Actinemys marmorata) at Vandenberg Air Force Base along the coast of central California in April 1995 and June 1996. We captured 179 individuals (115 males, 27 females) from 7 ponds during 26 days of trapping. Many turtles were adult-sized, but based on scute annuli, 74% were < 10 years of age, including many 2- to 3-year-olds. This population structure likely was due to a relatively fast growth rate, especially compared with closely related aquatic turtles in eastern North America. Mean clutch size was 5.2, but 66.7% of females were gravid, and 1 female produced 2 clutches. These reproductive data are similar to those reported for other populations in the southern portion of the species' range. Females reached reproductive maturity as early as 4 years of age. The relatively mild temperatures of California's Mediterranean climate, especially when compared to the seasonal extremes in more continental and northern regions of North America, may explain the different growth rates and population characteristics of freshwater turtles from these 2 regions of North America. ?? 2008 Chelonian Research Foundation.

Physical Growth, Biological Age, and Nutritional Transitions of Adolescents Living at Moderate Altitudes in Peru.

PubMed

Cossio-Bolaños, Marco; Campos, Rossana Gómez; Andruske, Cynthia Lee; Flores, Antonio Viveros; Luarte-Rocha, Cristian; Olivares, Pedro R; Garcia-Rubio, Javier; de Arruda, Miguel

2015-09-25

Peru is experiencing a stage of nutritional transition where the principal characteristics are typical of countries undergoing development. The objectives of this study were the following: (a) compare physical growth patterns with an international standard; (b) determine biological age; and (c) analyze the double nutritional burden of adolescents living at a moderate altitude in Peru. Weight, standing height, and sitting height were measured in 551 adolescents of both sexes (12.0 to 17.9 years old) from an urban area of Arequipa, Peru (2328 m). Physical growth was compared with the international standard of the CDC-2000. Biological age was determined by using a non-invasive transversal technique based on years from age at peak height velocity (APHV). Nutritional state was determined by means of weight for age and height for age. Z scores were calculated using international standards from the CDC-2000. Body weight for both sexes was similar to the CDC-2000 international standards. At all ages, the girls' height (p < 0.05) was below the standards. However, the boys' height (p < 0.05) was less at ages, 15, 16, and 17. Biological age showed up in girls at age 12.7 years and for boys at 15.2 years. Stunted growth (8.7% boys and 18.0% girls) and over weight (11.3% boys and 8.8% girls) occurred in both groups. A relationship existed in both sexes between the categories of weight for the age and stunted growth by sex. Adolescents living at a moderate altitude exhibited stunted linear growth and biological maturation. Furthermore, adolescents of both sexes showed the presence of the double nutritional burden (stunted growth and excessive weight).

Estimating age at a specified length from the von Bertalanffy growth function

USGS Publications Warehouse

Ogle, Derek H.; Isermann, Daniel A.

2017-01-01

Estimating the time required (i.e., age) for fish in a population to reach a specific length (e.g., legal harvest length) is useful for understanding population dynamics and simulating the potential effects of length-based harvest regulations. The age at which a population reaches a specific mean length is typically estimated by fitting a von Bertalanffy growth function to length-at-age data and then rearranging the best-fit equation to solve for age at the specified length. This process precludes the use of standard frequentist methods to compute confidence intervals and compare estimates of age at the specified length among populations. We provide a parameterization of the von Bertalanffy growth function that has age at a specified length as a parameter. With this parameterization, age at a specified length is directly estimated, and standard methods can be used to construct confidence intervals and make among-group comparisons for this parameter. We demonstrate use of the new parameterization with two data sets.

Influence of prenatal and postnatal growth on intellectual functioning in school-aged children.

PubMed

Pongcharoen, Tippawan; Ramakrishnan, Usha; DiGirolamo, Ann M; Winichagoon, Pattanee; Flores, Rafael; Singkhornard, Jintana; Martorell, Reynaldo

2012-05-01

To assess the relative influence of size at birth, infant growth, and late postnatal growth on intellectual functioning at 9 years of age. A follow-up, cross-sectional study. Three districts in Khon Kaen province, northeast Thailand. A total of 560 children, or 92% of former participants of a trial of iron and/or zinc supplementation during infancy. Prenatal (size at birth), early infancy (birth to 4 months), late infancy (4 months to 1 year), and late postnatal (1 to 9 years) growth. Multiple-stage least squares analyses were used to generate uncorrelated residuals of postnatal growth. Intellectual functioning was measured at 9 years using the Wechsler Intelligence Scale for Children and the Raven's Colored Progressive Matrices (Pearson). Analyses included adjustment for maternal, household, and school characteristics. Significant relationships were found between growth and IQ (Wechsler Intelligence Scale for children, third edition, Thai version), but only up to 1 year of age; overall, growth was not related to the Raven's Colored Progressive Matrices. The strongest and most consistent relationships were with length (birth, early infancy, and late infancy); for weight, only early infancy gain was consistently related to IQ. Head circumference at birth was not collected routinely; head circumference at 4 months (but not head circumference growth thereafter) was related to IQ. Late postnatal growth was not associated with any outcome. Physical growth in early infancy (and, to a lesser extent, physical growth in late infancy and at birth) is associated with IQ at 9 years of age. Early infancy may be a critical window for human development.

On the Importance of Aging to the Crack Growth Resistance of Human Enamel

PubMed Central

Yahyazadehfar, Mobin; Zhang, Dongsheng; Arola, Dwayne

2016-01-01

With improvements in oral health and an overall increase in quality of life, the percentage of fully or largely dentate seniors is increasing. Understanding the effects of aging on the mechanical properties of teeth is essential to the maintenance of lifelong oral health. In this investigation the effects of aging on the fracture toughness of human enamel were evaluated from incremental crack growth experiments performed on tissue of donor teeth representing “young” (17≤ age ≤ 25) and “old” (age ≥ 55) age groups. Results showed that the old enamel exhibited significantly lower resistance to fracture than that of the young tissue in two orthogonal directions of crack growth. For crack growth transverse to the enamel rods, the fracture toughness of the old enamel (0.37±0.15 MPa•m0.5) was nearly 70% lower than that of tissue from the young teeth (1.23±0.20 MPa•m0.5). Based on results from a mechanistic analysis of crack growth, the reduction in fracture resistance is attributed to a decreased in the degree of extrinsic toughening. The practice of restorative dentistry should account for these changes in tooth tissues in the treatment of senior patients. PMID:26747980

Residual Structures in Latent Growth Curve Modeling

ERIC Educational Resources Information Center

Grimm, Kevin J.; Widaman, Keith F.

2010-01-01

Several alternatives are available for specifying the residual structure in latent growth curve modeling. Two specifications involve uncorrelated residuals and represent the most commonly used residual structures. The first, building on repeated measures analysis of variance and common specifications in multilevel models, forces residual variances…

Effect of thermal implying during ageing process of nanorods growth on the properties of zinc oxide nanorod arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ismail, A. S., E-mail: kyrin-samaxi@yahoo.com; Mamat, M. H., E-mail: mhmamat@salam.uitm.edu.my; Rusop, M., E-mail: rusop@salam.uitm.my

Undoped and Sn-doped Zinc oxide (ZnO) nanostructures have been fabricated using a simple sol-gel immersion method at 95°C of growth temperature. Thermal sourced by hot plate stirrer was supplied to the solution during ageing process of nanorods growth. The results showed significant decrement in the quality of layer produced after the immersion process where the conductivity and porosity of the samples reduced significantly due to the thermal appliance. The structural properties of the samples have been characterized using field emission scanning electron microscopy (FESEM) electrical properties has been characterized using current voltage (I-V) measurement.

Reexamining the effects of gestational age, fetal growth, and maternal smoking on neonatal mortality

PubMed Central

Ananth, Cande V; Platt, Robert W

2004-01-01

Background Low birth weight (<2,500 g) is a strong predictor of infant mortality. Yet low birth weight, in isolation, is uninformative since it is comprised of two intertwined components: preterm delivery and reduced fetal growth. Through nonparametric logistic regression models, we examine the effects of gestational age, fetal growth, and maternal smoking on neonatal mortality. Methods We derived data on over 10 million singleton live births delivered at ≥ 24 weeks from the 1998–2000 U.S. natality data files. Nonparametric multivariable logistic regression based on generalized additive models was used to examine neonatal mortality (deaths within the first 28 days) in relation to fetal growth (gestational age-specific standardized birth weight), gestational age, and number of cigarettes smoked per day. All analyses were further adjusted for the confounding effects due to maternal age and gravidity. Results The relationship between standardized birth weight and neonatal mortality is nonlinear; mortality is high at low z-score birth weights, drops precipitously with increasing z-score birth weight, and begins to flatten for heavier infants. Gestational age is also strongly associated with mortality, with patterns similar to those of z-score birth weight. Although the direct effect of smoking on neonatal mortality is weak, its effects (on mortality) appear to be largely mediated through reduced fetal growth and, to a lesser extent, through shortened gestation. In fact, the association between smoking and reduced fetal growth gets stronger as pregnancies approach term. Conclusions Our study provides important insights regarding the combined effects of fetal growth, gestational age, and smoking on neonatal mortality. The findings suggest that the effect of maternal smoking on neonatal mortality is largely mediated through reduced fetal growth. PMID:15574192

Identification of growth phases and influencing factors in cultivations with AGE1.HN cells using set-based methods.

PubMed

Borchers, Steffen; Freund, Susann; Rath, Alexander; Streif, Stefan; Reichl, Udo; Findeisen, Rolf

2013-01-01

Production of bio-pharmaceuticals in cell culture, such as mammalian cells, is challenging. Mathematical models can provide support to the analysis, optimization, and the operation of production processes. In particular, unstructured models are suited for these purposes, since they can be tailored to particular process conditions. To this end, growth phases and the most relevant factors influencing cell growth and product formation have to be identified. Due to noisy and erroneous experimental data, unknown kinetic parameters, and the large number of combinations of influencing factors, currently there are only limited structured approaches to tackle these issues. We outline a structured set-based approach to identify different growth phases and the factors influencing cell growth and metabolism. To this end, measurement uncertainties are taken explicitly into account to bound the time-dependent specific growth rate based on the observed increase of the cell concentration. Based on the bounds on the specific growth rate, we can identify qualitatively different growth phases and (in-)validate hypotheses on the factors influencing cell growth and metabolism. We apply the approach to a mammalian suspension cell line (AGE1.HN). We show that growth in batch culture can be divided into two main growth phases. The initial phase is characterized by exponential growth dynamics, which can be described consistently by a relatively simple unstructured and segregated model. The subsequent phase is characterized by a decrease in the specific growth rate, which, as shown, results from substrate limitation and the pH of the medium. An extended model is provided which describes the observed dynamics of cell growth and main metabolites, and the corresponding kinetic parameters as well as their confidence intervals are estimated. The study is complemented by an uncertainty and outlier analysis. Overall, we demonstrate utility of set-based methods for analyzing cell growth and

Identification of Growth Phases and Influencing Factors in Cultivations with AGE1.HN Cells Using Set-Based Methods

PubMed Central

Borchers, Steffen; Freund, Susann; Rath, Alexander; Streif, Stefan; Reichl, Udo; Findeisen, Rolf

2013-01-01

Production of bio-pharmaceuticals in cell culture, such as mammalian cells, is challenging. Mathematical models can provide support to the analysis, optimization, and the operation of production processes. In particular, unstructured models are suited for these purposes, since they can be tailored to particular process conditions. To this end, growth phases and the most relevant factors influencing cell growth and product formation have to be identified. Due to noisy and erroneous experimental data, unknown kinetic parameters, and the large number of combinations of influencing factors, currently there are only limited structured approaches to tackle these issues. We outline a structured set-based approach to identify different growth phases and the factors influencing cell growth and metabolism. To this end, measurement uncertainties are taken explicitly into account to bound the time-dependent specific growth rate based on the observed increase of the cell concentration. Based on the bounds on the specific growth rate, we can identify qualitatively different growth phases and (in-)validate hypotheses on the factors influencing cell growth and metabolism. We apply the approach to a mammalian suspension cell line (AGE1.HN). We show that growth in batch culture can be divided into two main growth phases. The initial phase is characterized by exponential growth dynamics, which can be described consistently by a relatively simple unstructured and segregated model. The subsequent phase is characterized by a decrease in the specific growth rate, which, as shown, results from substrate limitation and the pH of the medium. An extended model is provided which describes the observed dynamics of cell growth and main metabolites, and the corresponding kinetic parameters as well as their confidence intervals are estimated. The study is complemented by an uncertainty and outlier analysis. Overall, we demonstrate utility of set-based methods for analyzing cell growth and

Physical Growth, Biological Age, and Nutritional Transitions of Adolescents Living at Moderate Altitudes in Peru

PubMed Central

Cossio-Bolaños, Marco; Gómez Campos, Rossana; Andruske, Cynthia Lee; Flores, Antonio Viveros; Luarte-Rocha, Cristian; Olivares, Pedro R.; Garcia-Rubio, Javier; de Arruda, Miguel

2015-01-01

Background: Peru is experiencing a stage of nutritional transition where the principal characteristics are typical of countries undergoing development. Objectives: The objectives of this study were the following: (a) compare physical growth patterns with an international standard; (b) determine biological age; and (c) analyze the double nutritional burden of adolescents living at a moderate altitude in Peru. Design: Weight, standing height, and sitting height were measured in 551 adolescents of both sexes (12.0 to 17.9 years old) from an urban area of Arequipa, Peru (2328 m). Physical growth was compared with the international standard of the CDC-2000. Biological age was determined by using a non-invasive transversal technique based on years from age at peak height velocity (APHV). Nutritional state was determined by means of weight for age and height for age. Z scores were calculated using international standards from the CDC-2000. Results: Body weight for both sexes was similar to the CDC-2000 international standards. At all ages, the girls’ height (p < 0.05) was below the standards. However, the boys’ height (p < 0.05) was less at ages, 15, 16, and 17. Biological age showed up in girls at age 12.7 years and for boys at 15.2 years. Stunted growth (8.7% boys and 18.0% girls) and over weight (11.3% boys and 8.8% girls) occurred in both groups. A relationship existed in both sexes between the categories of weight for the age and stunted growth by sex. Conclusions: Adolescents living at a moderate altitude exhibited stunted linear growth and biological maturation. Furthermore, adolescents of both sexes showed the presence of the double nutritional burden (stunted growth and excessive weight). PMID:26404334

Age structure and mortality of walleyes in Kansas reservoirs: Use of mortality caps to establish realistic management objectives

USGS Publications Warehouse

Quist, M.C.; Stephen, J.L.; Guy, C.S.; Schultz, R.D.

2004-01-01

Age structure, total annual mortality, and mortality caps (maximum mortality thresholds established by managers) were investigated for walleye Sander vitreus (formerly Stizostedion vitreum) populations sampled from eight Kansas reservoirs during 1991-1999. We assessed age structure by examining the relative frequency of different ages in the population; total annual mortality of age-2 and older walleyes was estimated by use of a weighted catch curve. To evaluate the utility of mortality caps, we modeled threshold values of mortality by varying growth rates and management objectives. Estimated mortality thresholds were then compared with observed growth and mortality rates. The maximum age of walleyes varied from 5 to 11 years across reservoirs. Age structure was dominated (???72%) by walleyes age 3 and younger in all reservoirs, corresponding to ages that were not yet vulnerable to harvest. Total annual mortality rates varied from 40.7% to 59.5% across reservoirs and averaged 51.1% overall (SE = 2.3). Analysis of mortality caps indicated that a management objective of 500 mm for the mean length of walleyes harvested by anglers was realistic for all reservoirs with a 457-mm minimum length limit but not for those with a 381-mm minimum length limit. For a 500-mm mean length objective to be realized for reservoirs with a 381-mm length limit, managers must either reduce mortality rates (e.g., through restrictive harvest regulations) or increase growth of walleyes. When the assumed objective was to maintain the mean length of harvested walleyes at current levels, the observed annual mortality rates were below the mortality cap for all reservoirs except one. Mortality caps also provided insight on management objectives expressed in terms of proportional stock density (PSD). Results indicated that a PSD objective of 20-40 was realistic for most reservoirs. This study provides important walleye mortality information that can be used for monitoring or for inclusion into

[Age structure and dynamics of Quercus wutaishanica population in Lingkong Mountain of Shanxi Province, China].

PubMed

Zhang, Jie; Shangguan, Tie-Liang; Duan, Yi-Hao; Guo, Wei; Liu, Wei-Hua; Guo, Dong-Gang

2014-11-01

Using the plant survivorship theory, the age structure, and the relationship between tree height and diameter (DBH) of Quercus wutaishanica population in Lingkong Mountain were analyzed, and the static life table was compiled and the survival curve plotted. The shuttle shape in age structure of Q. wutaishanica population suggested its temporal stability. The linear regression significantly fitted the positive correlation between tree height and DBH. The maximal life expectancy was observed among the trees beyond the age of the highest mortality and coincided with the lowest point of mortality density, suggesting the strong vitality of the seedlings and young trees that survived in the natural selection and intraspecific competition. The population stability of the Q. wutaishanica population was characterized by the Deevey-II of the survival curve. The dynamic pattern was characterized by the recession in the early phase, growth in the intermediate phase, and stability in the latter phase.

Predicting age from cortical structure across the lifespan.

PubMed

Madan, Christopher R; Kensinger, Elizabeth A

2018-03-01

Despite interindividual differences in cortical structure, cross-sectional and longitudinal studies have demonstrated a large degree of population-level consistency in age-related differences in brain morphology. This study assessed how accurately an individual's age could be predicted by estimates of cortical morphology, comparing a variety of structural measures, including thickness, gyrification and fractal dimensionality. Structural measures were calculated across up to seven different parcellation approaches, ranging from one region to 1000 regions. The age prediction framework was trained using morphological measures obtained from T1-weighted MRI volumes collected from multiple sites, yielding a training dataset of 1056 healthy adults, aged 18-97. Age predictions were calculated using a machine-learning approach that incorporated nonlinear differences over the lifespan. In two independent, held-out test samples, age predictions had a median error of 6-7 years. Age predictions were best when using a combination of cortical metrics, both thickness and fractal dimensionality. Overall, the results reveal that age-related differences in brain structure are systematic enough to enable reliable age prediction based on metrics of cortical morphology. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Advances in Structural Integrity Analysis Methods for Aging Metallic Airframe Structures with Local Damage

NASA Technical Reports Server (NTRS)

Starnes, James H., Jr.; Newman, James C., Jr.; Harris, Charles E.; Piascik, Robert S.; Young, Richard D.; Rose, Cheryl A.

2003-01-01

Analysis methodologies for predicting fatigue-crack growth from rivet holes in panels subjected to cyclic loads and for predicting the residual strength of aluminum fuselage structures with cracks and subjected to combined internal pressure and mechanical loads are described. The fatigue-crack growth analysis methodology is based on small-crack theory and a plasticity induced crack-closure model, and the effect of a corrosive environment on crack-growth rate is included. The residual strength analysis methodology is based on the critical crack-tip-opening-angle fracture criterion that characterizes the fracture behavior of a material of interest, and a geometric and material nonlinear finite element shell analysis code that performs the structural analysis of the fuselage structure of interest. The methodologies have been verified experimentally for structures ranging from laboratory coupons to full-scale structural components. Analytical and experimental results based on these methodologies are described and compared for laboratory coupons and flat panels, small-scale pressurized shells, and full-scale curved stiffened panels. The residual strength analysis methodology is sufficiently general to include the effects of multiple-site damage on structural behavior.

Adaptation of brain functional and structural networks in aging.

PubMed

Lee, Annie; Ratnarajah, Nagulan; Tuan, Ta Anh; Chen, Shen-Hsing Annabel; Qiu, Anqi

2015-01-01

The human brain, especially the prefrontal cortex (PFC), is functionally and anatomically reorganized in order to adapt to neuronal challenges in aging. This study employed structural MRI, resting-state fMRI (rs-fMRI), and high angular resolution diffusion imaging (HARDI), and examined the functional and structural reorganization of the PFC in aging using a Chinese sample of 173 subjects aged from 21 years and above. We found age-related increases in the structural connectivity between the PFC and posterior brain regions. Such findings were partially mediated by age-related increases in the structural connectivity of the occipital lobe within the posterior brain. Based on our findings, it is thought that the PFC reorganization in aging could be partly due to the adaptation to age-related changes in the structural reorganization of the posterior brain. This thus supports the idea derived from task-based fMRI that the PFC reorganization in aging may be adapted to the need of compensation for resolving less distinctive stimulus information from the posterior brain regions. In addition, we found that the structural connectivity of the PFC with the temporal lobe was fully mediated by the temporal cortical thickness, suggesting that the brain morphology plays an important role in the functional and structural reorganization with aging.

Onset of multiple sclerosis before adulthood leads to failure of age-expected brain growth

PubMed Central

Aubert-Broche, Bérengère; Fonov, Vladimir; Narayanan, Sridar; Arnold, Douglas L.; Araujo, David; Fetco, Dumitru; Till, Christine; Sled, John G.; Collins, D. Louis

2014-01-01

Objective: To determine the impact of pediatric-onset multiple sclerosis (MS) on age-expected brain growth. Methods: Whole brain and regional volumes of 36 patients with relapsing-remitting MS onset prior to 18 years of age were segmented in 185 longitudinal MRI scans (2–11 scans per participant, 3-month to 2-year scan intervals). MRI scans of 25 age- and sex-matched healthy normal controls (NC) were also acquired at baseline and 2 years later on the same scanner as the MS group. A total of 874 scans from 339 participants from the NIH-funded MRI study of normal brain development acquired at 2-year intervals were used as an age-expected healthy growth reference. All data were analyzed with an automatic image processing pipeline to estimate the volume of brain and brain substructures. Mixed-effect models were built using age, sex, and group as fixed effects. Results: Significant group and age interactions were found with the adjusted models fitting brain volumes and normalized thalamus volumes (p < 10−4). These findings indicate a failure of age-normative brain growth for the MS group, and an even greater failure of thalamic growth. In patients with MS, T2 lesion volume correlated with a greater reduction in age-expected thalamic volume. To exclude any scanner-related influence on our data, we confirmed no significant interaction of group in the adjusted models between the NC and NIH MRI Study of Normal Brain Development groups. Conclusions: Our results provide evidence that the onset of MS during childhood and adolescence limits age-expected primary brain growth and leads to subsequent brain atrophy, implicating an early onset of the neurodegenerative aspect of MS. PMID:25378667

Cognitive ability in adolescents born small for gestational age: Associations with fetal growth velocity, head circumference and postnatal growth.

PubMed

Jensen, Rikke Beck; Juul, Anders; Larsen, Torben; Mortensen, Erik Lykke; Greisen, Gorm

2015-12-01

Small size at birth may be associated with impaired cognitive ability later in life. The aim of this study was to examine the effect of being born small for gestational age (SGA), with or without intrauterine growth restriction (IUGR) on cognitive ability in late adolescence. A follow-up study of a former cohort included 123 participants (52 males); 47 born SGA and 76 born appropriate for gestational age (AGA). Fetal growth velocity (FGV) was determined by serial ultrasound measurements during the third trimester. A control group matched for age and birthplace was included. The original Wechsler Adult Intelligence Scale (WAIS) was administered, and verbal, performance and full-scale Intelligence Quotient (IQ) scores were calculated. There was no difference in IQ between adolescents born SGA and AGA. FGV or IUGR during the third trimester did not influence cognitive ability in late adolescence. Full-scale IQ was positively related to head circumference (HC) in adolescence (B: 1.30, 95% CI: 0.32-2.28, p=0.01). HC at birth and three months was positively associated with full-scale IQ. Catch-up growth in the group of SGA children was associated with a significantly increased height, larger HC, increased levels of insulin-like growth factor-I (IGF-I) and increased full-scale IQ compared to those born SGA without catch-up growth. SGA and IUGR may not be harmful for adult cognitive ability, at least not in individuals born at near-term. However, known risk factors of impaired fetal growth may explain the link between early growth and cognitive ability in adulthood. Copyright © 2015. Published by Elsevier Ireland Ltd.

Species composition, size structure, and disturbance: History of an old growth bottomland hardwood loblolly pine (Pinus taeda) forest in Arkansas, USA

Treesearch

Eric Heitzman; Michael G. Shelton; Adrian Grell

2004-01-01

The Lost Forty is a 16-ha old-growth bottomland hardwood-lobtolly pine (Pinus taeda L.) forest iocated in south-central Arkansas that has had little human disturbance. We established plots in the Lost Forty and collected data on species composition, tree size, age structure, and radial stem growth patterns. The overstory was dominated by species that...

Evolution of stochastic demography with life history tradeoffs in density-dependent age-structured populations.

PubMed

Lande, Russell; Engen, Steinar; Sæther, Bernt-Erik

2017-10-31

We analyze the stochastic demography and evolution of a density-dependent age- (or stage-) structured population in a fluctuating environment. A positive linear combination of age classes (e.g., weighted by body mass) is assumed to act as the single variable of population size, [Formula: see text], exerting density dependence on age-specific vital rates through an increasing function of population size. The environment fluctuates in a stationary distribution with no autocorrelation. We show by analysis and simulation of age structure, under assumptions often met by vertebrate populations, that the stochastic dynamics of population size can be accurately approximated by a univariate model governed by three key demographic parameters: the intrinsic rate of increase and carrying capacity in the average environment, [Formula: see text] and [Formula: see text], and the environmental variance in population growth rate, [Formula: see text] Allowing these parameters to be genetically variable and to evolve, but assuming that a fourth parameter, [Formula: see text], measuring the nonlinearity of density dependence, remains constant, the expected evolution maximizes [Formula: see text] This shows that the magnitude of environmental stochasticity governs the classical trade-off between selection for higher [Formula: see text] versus higher [Formula: see text] However, selection also acts to decrease [Formula: see text], so the simple life-history trade-off between [Formula: see text]- and [Formula: see text]-selection may be obscured by additional trade-offs between them and [Formula: see text] Under the classical logistic model of population growth with linear density dependence ([Formula: see text]), life-history evolution in a fluctuating environment tends to maximize the average population size. Published under the PNAS license.

Fame and obsolescence: Disentangling growth and aging dynamics of patent citations.

PubMed

Higham, K W; Governale, M; Jaffe, A B; Zülicke, U

2017-04-01

We present an analysis of citations accrued over time by patents granted by the United States Patent and Trademark Office in 1998. In contrast to previous studies, a disaggregation by technology category is performed, and exogenously caused citation-number growth is controlled for. Our approach reveals an intrinsic citation rate that clearly separates into an-in the long run, exponentially time-dependent-aging function and a completely time-independent preferential-attachment-type growth kernel. For the general case of such a separable citation rate, we obtain the time-dependent citation distribution analytically in a form that is valid for any functional form of its aging and growth parts. Good agreement between theory and long-time characteristics of patent-citation data establishes our work as a useful framework for addressing still open questions about knowledge-propagation dynamics, such as the observed excess of citations at short times.

Fame and obsolescence: Disentangling growth and aging dynamics of patent citations

NASA Astrophysics Data System (ADS)

Higham, K. W.; Governale, M.; Jaffe, A. B.; Zülicke, U.

2017-04-01

We present an analysis of citations accrued over time by patents granted by the United States Patent and Trademark Office in 1998. In contrast to previous studies, a disaggregation by technology category is performed, and exogenously caused citation-number growth is controlled for. Our approach reveals an intrinsic citation rate that clearly separates into an—in the long run, exponentially time-dependent—aging function and a completely time-independent preferential-attachment-type growth kernel. For the general case of such a separable citation rate, we obtain the time-dependent citation distribution analytically in a form that is valid for any functional form of its aging and growth parts. Good agreement between theory and long-time characteristics of patent-citation data establishes our work as a useful framework for addressing still open questions about knowledge-propagation dynamics, such as the observed excess of citations at short times.

Age validation and growth of bluenose Hyperoglyphe antarctica using the bomb chronometer method of radiocarbon ageing.

PubMed

Horn, P L; Neil, H L; Paul, L J; Marriott, P

2010-11-01

Age validation of bluenose Hyperoglyphe antarctica was sought using the independent bomb chronometer procedure. Radiocarbon ((14) C) levels were measured in core micro-samples from 12 otoliths that had been aged using a zone count method. The core (14) C measurement for each fish was compared with the value on a surface water reference curve for the calculated birth year of the fish. There was good agreement, indicating that the line-count ageing method described here is not substantially biased. A second micro-sample was also taken near the edge of nine of the otolith cross-sections to help define a bomb-carbon curve for waters deeper than 200-300 m. There appears to be a 10 to 15 year lag in the time it takes the (14) C to reach the waters where adult H. antarctica are concentrated. The maximum estimated age of this species was 76 years, and females grow significantly larger than males. Von Bertalanffy growth curves were estimated, and although they fit the available data reasonably well, the lack of aged juvenile fish results in the K and t(0) parameters being biologically meaningless. Consequently, curves that are likely to better represent population growth were estimated by forcing t(0) to be -0·5. © 2010 NIWA. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.

Age structure and age-related performance of sulfur cinquefoil (Potentilla recta).

Treesearch

Dana L. Perkins; Catherine G. Parks; Kathleen A. Dwire; Bryan A. Endress; Kelsi L. Johnson

2006-01-01

Age distributions of sulfur cinquefoil populations were determined on sites that were historically grazed, cultivated, and mechanically disturbed. From 12 sites, a total of 279 reproductively active plants were collected and aged by using herbchronology (counting rings in the secondary root xylem of the root crown) to (1) estimate the age structure of the populations...

Structure of S-shaped growth in innovation diffusion

NASA Astrophysics Data System (ADS)

Shimogawa, Shinsuke; Shinno, Miyuki; Saito, Hiroshi

2012-05-01

A basic question on innovation diffusion is why the growth curve of the adopter population in a large society is often S shaped. From macroscopic, microscopic, and mesoscopic viewpoints, the growth of the adopter population is observed as the growth curve, individual adoptions, and differences among individual adoptions, respectively. The S shape can be explained if an empirical model of the growth curve can be deduced from models of microscopic and mesoscopic structures. However, even the structure of growth curve has not been revealed yet because long-term extrapolations by proposed models of S-shaped curves are unstable and it has been very difficult to predict the long-term growth and final adopter population. This paper studies the S-shaped growth from the viewpoint of social regularities. Simple methods to analyze power laws enable us to extract the structure of the growth curve directly from the growth data of recent basic telecommunication services. This empirical model of growth curve is singular at the inflection point and a logarithmic function of time after this point, which explains the unstable extrapolations obtained using previously proposed models and the difficulty in predicting the final adopter population. Because the empirical S curve can be expressed in terms of two power laws of the regularity found in social performances of individuals, we propose the hypothesis that the S shape represents the heterogeneity of the adopter population, and the heterogeneity parameter is distributed under the regularity in social performances of individuals. This hypothesis is so powerful as to yield models of microscopic and mesoscopic structures. In the microscopic model, each potential adopter adopts the innovation when the information accumulated by the learning about the innovation exceeds a threshold. The accumulation rate of information is heterogeneous among the adopter population, whereas the threshold is a constant, which is the opposite of previously

Climatic Stress during Stand Development Alters the Sign and Magnitude of Age-Related Growth Responses in a Subtropical Mountain Pine.

PubMed

Ruiz-Benito, Paloma; Madrigal-González, Jaime; Young, Sarah; Mercatoris, Pierre; Cavin, Liam; Huang, Tsurng-Juhn; Chen, Jan-Chang; Jump, Alistair S

2015-01-01

The modification of typical age-related growth by environmental changes is poorly understood, In part because there is a lack of consensus at individual tree level regarding age-dependent growth responses to climate warming as stands develop. To increase our current understanding about how multiple drivers of environmental change can modify growth responses as trees age we used tree ring data of a mountain subtropical pine species along an altitudinal gradient covering more than 2,200 m of altitude. We applied mixed-linear models to determine how absolute and relative age-dependent growth varies depending on stand development; and to quantify the relative importance of tree age and climate on individual tree growth responses. Tree age was the most important factor for tree growth in models parameterised using data from all forest developmental stages. Contrastingly, the relationship found between tree age and growth became non-significant in models parameterised using data corresponding to mature stages. These results suggest that although absolute tree growth can continuously increase along tree size when trees reach maturity age had no effect on growth. Tree growth was strongly reduced under increased annual temperature, leading to more constant age-related growth responses. Furthermore, young trees were the most sensitive to reductions in relative growth rates, but absolute growth was strongly reduced under increased temperature in old trees. Our results help to reconcile previous contrasting findings of age-related growth responses at the individual tree level, suggesting that the sign and magnitude of age-related growth responses vary with stand development. The different responses found to climate for absolute and relative growth rates suggest that young trees are particularly vulnerable under warming climate, but reduced absolute growth in old trees could alter the species' potential as a carbon sink in the future.

Effect of age on structural properties of intramuscular connective tissue, muscle fibre, collagen content and meat tenderness in pig longissimus lumborum muscle.

PubMed

Wojtysiak, Dorota

2013-01-01

Changes in the structure and properties of the intramuscular connective tissue, muscle fibre size, collagen content and meat tenderness of m. longissimus lumborum during growth was studied in 45 Polish Large White (PLW) pigs slaughtered at 90, 150 and 210 days of age. The results show that the endomysial sheath in m. longissimus lumborum consists of collagen fibrils of wavy appearance which run in all directions and form a loose network. The arrangement of collagen fibrils in the endomysium and perimysium becomes denser and more regular with increasing age of pigs. In addition, the increase in endomysium and perimysium thickness was paralleled by a significant increase in muscle fibre diameter, as well as an increase in shear force value with chronological aging. In contrast, the percentage of collagen area in muscle structure and the amount of total collagen and amount of soluble collagen decreased gradually with age of pigs. In conclusion, the structural changes in the arrangement of collagen fibres in the architecture of intramusclular connective tissue, as well as the decrease in soluble collagen content in m. longissimus lumborum during growth of pigs are important factors influencing shear force value, and thus raw meat tenderness.

Age and growth dynamics of Tyrannosaurus rex.

PubMed

Horner, John R; Padian, Kevin

2004-09-22

Tyrannosaurus rex is the most commonly found North American latest Cretaceous theropod, but until the 1980s only five specimens had been discovered, and no more than six have received a full description. Consequently there has been little information on how old Tyrannosaurus specimens were at maturity or death. Histological analysis of seven individuals provided, for the first time, an opportunity to assess the age represented by the bone cortex, to estimate the average individual age of these skeletons, to determine whether they represented fully grown individuals, and to predict their individual longevity. Though a range of ages (15-25 years) was found for the specimens studied, the seven individuals demonstrate that T. rex reached effectively full size in less than 20 years. The growth rate of T. rex was comparable to that of the African elephant, which has a similar mass and time to maturity. Some of the known specimens of T. rex did not quite reach full size; others do not seem to have survived long after achieving it.

Age and growth dynamics of Tyrannosaurus rex.

PubMed Central

Horner, John R.; Padian, Kevin

2004-01-01

Tyrannosaurus rex is the most commonly found North American latest Cretaceous theropod, but until the 1980s only five specimens had been discovered, and no more than six have received a full description. Consequently there has been little information on how old Tyrannosaurus specimens were at maturity or death. Histological analysis of seven individuals provided, for the first time, an opportunity to assess the age represented by the bone cortex, to estimate the average individual age of these skeletons, to determine whether they represented fully grown individuals, and to predict their individual longevity. Though a range of ages (15-25 years) was found for the specimens studied, the seven individuals demonstrate that T. rex reached effectively full size in less than 20 years. The growth rate of T. rex was comparable to that of the African elephant, which has a similar mass and time to maturity. Some of the known specimens of T. rex did not quite reach full size; others do not seem to have survived long after achieving it. PMID:15347508

The birth, growth and ageing of the Kaapvaal subcratonic mantle

NASA Astrophysics Data System (ADS)

Brey, Gerhard P.; Shu, Qiao

2018-06-01

The Kaapvaal craton and its underlying mantle is probably one of the best studied Archean entity in the world. Despite that, discussion is still vivid on important aspects. A major debate over the last few decades is the depth of melting that generated the mantle nuclei of cratons. Our new evaluation of melting parameters in peridotite residues shows that the Cr2O3/Al2O3 ratio is the most useful pressure sensitive melting barometer. It irrevocably constrains the pressure of melting (melt separation) to less than 2 GPa with olivine (ol), orthopyroxene (opx) and spinel (sp) as residual phases. Garnet (grt) grows at increasing pressure during lithosphere thickening and subduction via the reaction opx + sp → grt + ol. The time of partial melting is constrained by Re-depletion model ages (TRD) mainly to the Archean (Pearson and Wittig 2008). However, only 3% of the ages are older than 3.1 Ga while crustal ages lie mainly between 3.1 to 2.8 Ga for the W- and 3.7 to 2.8 Ga for the E-block. Many TRD-ages are probably falsified by metasomatism and the main partial melting period was older than 3.1 Ga. Also, Nd- and Hf- model ages of peridotitic lithologies from the W-block are 3.2 to 3.6 Ga old. The corresponding very negative ɛNd (-40) and ɛHf values (-65) signal the presence of subducted crustal components in these old mantle portions. Subducted components diversify the mantle in its chemistry and thermal structure. Adjustment towards a stable configuration occurs by fluid transfer, metasomatism, partial melting and heat transfer. Ages of metasomatism from the Lu-Hf isotope system are 3.2 Ga (Lace), 2.9 Ga (Roberts Victor) and 2.62 Ga (Finsch) coinciding with the collision of cratonic blocks, the growth of diamonds, metamorphism of eclogites and of Ventersdoorp magmatism. The cratonic lithosphere was stabilized thermally by the end of the Archean and cooled since then with a rate of 0.07 °C/Ma.

Early growth patterns are associated with intelligence quotient scores in children born small-for-gestational age.

PubMed

Varella, Marcia H; Moss, William J

2015-08-01

To assess whether patterns of growth trajectory during infancy are associated with intelligence quotient (IQ) scores at 4 years of age in children born small-for-gestational age (SGA). Children in the Collaborative Perinatal Project born SGA were eligible for analysis. The primary outcome was the Stanford-Binet IQ score at 4 years of age. Growth patterns were defined based on changes in weight-for-age z-scores from birth to 4 months and 4 to 12 months of age and consisted of steady, early catch-up, late catch-up, constant catch-up, early catch-down, late catch-down, constant catch-down, early catch-up & late catch-down, and early catch-down & late catch-up. Multivariate linear regression was used to assess associations between patterns of growth and IQ. We evaluated patterns of growth and IQ in 5640 children. Compared with children with steady growth, IQ scores were 2.9 [standard deviation (SD)=0.54], 1.5 (SD=0.63), and 2.2 (SD=0.9) higher in children with early catch-up, early catch-up and later catch-down, and constant catch-up growth patterns, respectively, and 4.4 (SD=1.4) and 3.9 (SD=1.5) lower in children with early catch-down & late catch-up, and early catch-down growth patterns, respectively. Patterns in weight gain before 4 months of age were associated with differences in IQ scores at 4 years of age, with children with early catch-up having slightly higher IQ scores than children with steady growth and children with early catch-down having slightly lower IQ scores. These findings have implications for early infant nutrition in children born SGA. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Growth of site trees and stand structure in mixed stands of Pacific silver fir and western hemlock.

Treesearch

Marshall D. Murray; Peggy C. Leonard

1990-01-01

Height and diameter growth of Pacific silver fir (Abies amabilis Dougl. ex Forbes) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) site trees, as well as overall stand structure on 0.15-acre plots, were analyzed in mixed stands 43 to 57 years old in breast height age at six locations in western Washington. These mixed...

[Weight and height local growth charts of Algerian children and adolescents (6-18 years of age)].

PubMed

Bahchachi, N; Dahel-Mekhancha, C C; Rolland-Cachera, M F; Badis, N; Roelants, M; Hauspie, R; Nezzal, L

2016-04-01

Measurements of height and weight provide important information on growth and development, puberty, and nutritional status in children and adolescents. The aim of this study was to develop contemporary reference growth centiles for Algerian children and adolescents (6-18 years of age). A cross-sectional growth survey was conducted in government schools on 7772 healthy schoolchildren (45.1% boys and 54.9% girls) aged 6-18 years in Constantine (eastern Algeria) in 2008. Height and weight were measured with portable stadiometers and calibrated scales, respectively. Smooth reference curves of height and weight were estimated with the LMS method. These height and weight curves are presented together with local data from Arab countries and with the growth references of France, Belgium (Flanders), and the World Health Organization (WHO) 2007. In girls, median height and weight increased until 16 and 17 years of age, respectively, whereas in boys, they increased through age 18 years. Between ages 11 and 13 years (puberty), girls were taller and heavier than boys. After puberty, boys became taller than girls, by up to 13 cm by the age of 18 years. Median height and weight of Algerian boys and girls were generally intermediate between those observed in other Arab countries. They were higher than the French reference values up to the age of 13 years and lower than Belgian and WHO reference values at all ages. The present study provides Algerian height- and weight-for-age growth charts, which should be recommended as a national reference for monitoring growth and development in children and adolescents. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Physics of Lipofuscin Formation and Growth in Age Related Macular Degeneration

NASA Astrophysics Data System (ADS)

Family, Fereydoon; Mazzitello, K. I.; Arizmendi, C. M.; Grossniklaus, Hans E.

2010-02-01

Age-related macular degeneration (AMD) is the leading cause of blindness beyond the age of 50 years. The most common pathogenic mechanism that leads to AMD is choroidal neovascularization (CNV). CNV is produced by accumulation of residual material caused by aging of retinal pigment epithelium cells (RPE). With time, incompletely degraded membrane material builds up in the RPE in the form of lipofuscin. Lipofuscin is made of free-radical-damaged protein and fat, which forms not only in AMD, but also Alzheimer disease, and Parkinson disease. We will present the results of a study of the kinetics of lipofuscin growth in RPE cells using Kinetic Monte Carlo simulations and scaling theory on a cluster aggregation model. The model captures the essential physics of lipofuscin growth in the cells. A remarkable feature is that small particles may be removed from the cells while the larger ones become fixed and grow by aggregation. We compare our results to the number of lipofuscin granules in eyes with early age-related degeneration. )

On the structure-bounded growth processes in plant populations.

PubMed

Kilian, H G; Kazda, M; Király, F; Kaufmann, D; Kemkemer, R; Bartkowiak, D

2010-07-01

If growing cells in plants are considered to be composed of increments (ICs) an extended version of the law of mass action can be formulated. It evidences that growth of plants runs optimal if the reaction-entropy term (entropy times the absolute temperature) matches the contact energy of ICs. Since these energies are small, thermal molecular movements facilitate via relaxation the removal of structure disturbances. Stem diameter distributions exhibit extra fluctuations likely to be caused by permanent constraints. Since the signal-response system enables in principle perfect optimization only within finite-sized cell ensembles, plants comprising relatively large cell numbers form a network of size-limited subsystems. The maximal number of these constituents depends both on genetic and environmental factors. Accounting for logistical structure-dynamics interrelations, equations can be formulated to describe the bimodal growth curves of very different plants. The reproduction of the S-bended growth curves verifies that the relaxation modes with a broad structure-controlled distribution freeze successively until finally growth is fully blocked thus bringing about "continuous solidification".

Growth curve analyses of the relationship between early maternal age and children's mathematics and reading performance.

PubMed

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.

Accelerated Aging Experiments for Prognostics of Damage Growth in Composite Materials

NASA Technical Reports Server (NTRS)

Saxena, Abhinav; Goebel, Kai Frank; Larrosa, Cecilia C.; Janapati, Vishnuvardhan; Roy, Surajit; Chang, Fu-Kuo

2011-01-01

Composite structures are gaining importance for use in the aerospace industry. Compared to metallic structures their behavior is less well understood. This lack of understanding may pose constraints on their use. One possible way to deal with some of the risks associated with potential failure is to perform in-situ monitoring to detect precursors of failures. Prognostic algorithms can be used to predict impending failures. They require large amounts of training data to build and tune damage model for making useful predictions. One of the key aspects is to get confirmatory feedback from data as damage progresses. These kinds of data are rarely available from actual systems. The next possible resource to collect such data is an accelerated aging platform. To that end this paper describes a fatigue cycling experiment with the goal to stress carbon-carbon composite coupons with various layups. Piezoelectric disc sensors were used to periodically interrogate the system. Analysis showed distinct differences in the signatures of growing failures between data collected at conditions. Periodic X-radiographs were taken to assess the damage ground truth. Results after signal processing showed clear trends of damage growth that were correlated to damage assessed from the X-ray images.

[Correlation of dental age and anthropometric parametres of the overall growth and development in children].

PubMed

Triković-Janjić, Olivera; Apostolović, Mirjana; Janosević, Mirjana; Filipović, Gordana

2008-02-01

Anthropometric methods of measuring the whole body and body parts are the most commonly applied methods of analysing the growth and development of children. Anthropometric measures are interconnected, so that with growth and development the change of one of the parameters causes the change of the other. The aim of the paper was to analyse whether dental development follows the overall growth and development and what the ratio of this interdependence is. The research involved a sample of 134 participants, aged between 6 and 8 years. Dental age was determined as the average of the sum of existing permanent teeth from the participants aged 6, 7 and 8. With the aim of analysing physical growth and development, commonly accepted anthropometric indexes were applied: height, weight, circumference of the head, the chest cavity at its widest point, the upper arm, the abdomen, the thigh and thickness of the epidermis. The dimensions were measured according to the methodology of the International Biological Programme. The influence of the pertinent variables' related size on the analysed variable was deter mined by the statistical method of multivariable regression. The middle values of all the anthropometric parametres, except for the thickness of the epidermis, were slightly bigger with male participants, and the circumference of the chest cavity was statistically considerably bigger (p < 0.05). The results of anthropometric measurement showed in general a distinct homogeneity not only of the sample group but also within gender, in relation to all the dimensions, excyt for the thickness of the epidermis. The average of the dental age of the participants was 10.36, (10.42 and 10.31 for females and males respectively). Considerable correlation (R = 0.59) with high statistical significance (p < 0.001) was determined between dental age and the set of anthropometric parameters of general growth and development. There is a considerable positive correlation (R = 0.59) between

Occupations Classified by Their Age Structure

ERIC Educational Resources Information Center

Smith, John M.

1975-01-01

An analysis of occupational age structures for males has pragmatic implications for vocational advice and decisions (particularly for older workers), personnel and manpower planning, and experimental research. (A 5-page appendix lists occupational age ratios for 2( categories of occupations based on 1961 census data.) (Author/AG)

Impact of Maternal Depressive Symptoms on Growth of Preschool- and School-Aged Children

PubMed Central

Ettinger, Anna K.; Ahmed, Saifuddin; Minkovitz, Cynthia S.; Strobino, Donna

2012-01-01

OBJECTIVE: The aim of our study was to examine whether maternal depressive symptoms at 9 months postpartum adversely affect growth in preschool- and school-aged children. METHODS: We used data from the US nationally representative Early Childhood Longitudinal Study, Birth Cohort. We fit multivariable logistic regression models to study maternal depressive symptoms at 9 months postpartum (using the Center for Epidemiologic Studies Depression Scale) in relation to child growth outcomes, ≤10% height-for-age, ≤10% weight-for-height, and ≤10% weight-for-age at 4 and 5 years. RESULTS: At 9 months, 24% of mothers reported mild depressive symptoms and 17% moderate/severe symptoms. After adjustment for household, maternal, and child factors, children of mothers with moderate to severe levels of depressive symptoms at 9 months’ postpartum had a 40% increased odds of being ≤10% in height-for-age at age 4 (odds ratio = 1.40, 95% confidence interval: 1.04–1.89) and 48% increased odds of being ≤10% in height-for-age at age 5 (odds ratio = 1.48, 95% confidence interval: 1.03–2.13) compared with children of women with few or no depressive symptoms. There was no statistically significant association between maternal depressive symptoms and children being ≤10% in weight-for-height and weight-for-age at 4 or 5 years. CONCLUSIONS: Maternal depressive symptoms during infancy may affect physical growth in early childhood. Prevention, early detection, and treatment of maternal depressive symptoms during the first year postpartum may prevent childhood height-for-age ≤10th percentile among preschool- and school-aged children. PMID:22966023

Aging, mortality, and the fast growth trade-off of Schizosaccharomyces pombe

PubMed Central

Nakaoka, Hidenori; Wakamoto, Yuichi

2017-01-01

Replicative aging has been demonstrated in asymmetrically dividing unicellular organisms, seemingly caused by unequal damage partitioning. Although asymmetric segregation and inheritance of potential aging factors also occur in symmetrically dividing species, it nevertheless remains controversial whether this results in aging. Based on large-scale single-cell lineage data obtained by time-lapse microscopy with a microfluidic device, in this report, we demonstrate the absence of replicative aging in old-pole cell lineages of Schizosaccharomyces pombe cultured under constant favorable conditions. By monitoring more than 1,500 cell lineages in 7 different culture conditions, we showed that both cell division and death rates are remarkably constant for at least 50–80 generations. Our measurements revealed that the death rate per cellular generation increases with the division rate, pointing to a physiological trade-off with fast growth under balanced growth conditions. We also observed the formation and inheritance of Hsp104-associated protein aggregates, which are a potential aging factor in old-pole cell lineages, and found that these aggregates exhibited a tendency to preferentially remain at the old poles for several generations. However, the aggregates were eventually segregated from old-pole cells upon cell division and probabilistically allocated to new-pole cells. We found that cell deaths were typically preceded by sudden acceleration of protein aggregation; thus, a relatively large amount of protein aggregates existed at the very ends of the dead cell lineages. Our lineage tracking analyses, however, revealed that the quantity and inheritance of protein aggregates increased neither cellular generation time nor cell death initiation rates. Furthermore, our results demonstrated that unusually large amounts of protein aggregates induced by oxidative stress exposure did not result in aging; old-pole cells resumed normal growth upon stress removal, despite the

On the importance of aging to the crack growth resistance of human enamel.

PubMed

Yahyazadehfar, Mobin; Zhang, Dongsheng; Arola, Dwayne

2016-03-01

With improvements in oral health and an overall increase in quality of life, the percentage of fully or largely dentate seniors is increasing. Understanding the effects of aging on the mechanical properties of teeth is essential to the maintenance of lifelong oral health. In this investigation the effects of aging on the fracture toughness of human enamel were evaluated from incremental crack growth experiments performed on tissue of donor teeth representing "young" (17 ⩽ age ⩽ 25) and "old" (age ⩾ 55) age groups. Results showed that the old enamel exhibited significantly lower resistance to fracture than that of the young tissue in two orthogonal directions of crack growth. For crack growth transverse to the enamel rods, the fracture toughness of the old enamel (0.37 ± 0.15 MPa m(0.5)) was nearly 70% lower than that of tissue from the young teeth (1.23 ± 0.20 MPa m(0.5)). Based on results from a mechanistic analysis of crack growth, the reduction in fracture resistance is attributed to a decrease in the degree of extrinsic toughening. The practice of restorative dentistry should account for these changes in tooth tissues in the treatment of senior patients. The mechanical behavior of enamel has been studied for over 3 decades. Due to the limited volume of tissue available for evaluation, past work has been largely based on indentation methods. In this investigation we have evaluated the resistance to fracture of human enamel using a conventional fracture mechanics approach and incremental crack growth. We compared the fracture resistance of cuspal enamel obtained from the teeth of representative "young" and "old" donor groups. Our results show that there is a substantial reduction in the resistance to fracture with age, that it is anisotropic, and that the degradation is more severe than that which occurs to dentin. As such, we feel this work is a significant contribution to the field. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All

Childhood growth and development associated with need for full-time special education at school age.

PubMed

Mannerkoski, Minna; Aberg, Laura; Hoikkala, Marianne; Sarna, Seppo; Kaski, Markus; Autti, Taina; Heiskala, Hannu

2009-01-01

To explore how growth measurements and attainment of developmental milestones in early childhood reflect the need for full-time special education (SE). After stratification in this population-based study, 900 pupils in full-time SE groups (age-range 7-16 years, mean 12 years 8 months) at three levels and 301 pupils in mainstream education (age-range 7-16, mean 12 years 9 months) provided data on height and weight from birth to age 7 years and head circumference to age 1 year. Developmental screening was evaluated from age 1 month to 48 months. Statistical methods included a general linear model (growth measurements), binary logistic regression analysis (odds ratios for growth), and multinomial logistic regression analysis (odds ratios for developmental milestones). At 1 year, a 1 standard deviation score (SDS) decrease in height raised the probability of SE placement by 40%, and a 1 SDS decrease in head size by 28%. In developmental screening, during the first months of life the gross motor milestones, especially head support, differentiated the children at levels 0-3. Thereafter, the fine motor milestones and those related to speech and social skills became more important. Children whose growth is mildly impaired, though in the normal range, and who fail to attain certain developmental milestones have an increased probability for SE and thus a need for special attention when toddlers age. Similar to the growth curves, these children seem to have consistent developmental curves (patterns).

Disease spread in age structured populations with maternal age effects.

PubMed

Clark, Jessica; Garbutt, Jennie S; McNally, Luke; Little, Tom J

2017-04-01

Fundamental ecological processes, such as extrinsic mortality, determine population age structure. This influences disease spread when individuals of different ages differ in susceptibility or when maternal age determines offspring susceptibility. We show that Daphnia magna offspring born to young mothers are more susceptible than those born to older mothers, and consider this alongside previous observations that susceptibility declines with age in this system. We used a susceptible-infected compartmental model to investigate how age-specific susceptibility and maternal age effects on offspring susceptibility interact with demographic factors affecting disease spread. Our results show a scenario where an increase in extrinsic mortality drives an increase in transmission potential. Thus, we identify a realistic context in which age effects and maternal effects produce conditions favouring disease transmission. © 2017 The Authors Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Growth and tolerance of formula with lactoferrin in infants through one year of age: double-blind, randomized, controlled trial.

PubMed

Johnston, William H; Ashley, Claude; Yeiser, Michael; Harris, Cheryl L; Stolz, Suzanne I; Wampler, Jennifer L; Wittke, Anja; Cooper, Timothy R

2015-11-07

Human milk provides necessary macronutrients (protein, carbohydrate, fat) required for infant nutrition. Lactoferrin (Lf), a multifunctional iron-binding protein predominant in human milk, shares similar protein sequence, structure, and bioactivity with bovine Lf (bLf). This large-scale pediatric nutrition study was designed to evaluate growth and tolerance in healthy infants who received study formulas with bLf at concentrations within the range of mature human milk. In this multi-center, double-blind, parallel-designed, gender-stratified prospective study 480 infants were randomized to receive a marketed routine cow's milk-based infant formula (Control; n = 155) or one of two investigational formulas with bLf at 0.6 g/L (LF-0.6; n = 165) or 1.0 g/L (LF-1.0; n = 160) from 14-365 days of age. Investigational formulas also had a prebiotic blend of polydextrose (PDX) and galactooligosaccharides (GOS) and adjusted arachidonic acid (ARA). The primary outcome was weight growth rate from 14-120 days of age. Anthropometric measurements were taken at 14, 30, 60, 90, 120, 180, 275, and 365 days of age. Parental recall of formula intake, tolerance, and stool characteristics was collected at each time point. Medically-confirmed adverse events were collected throughout the study period. There were no group differences in growth rate (g/day) from 14-120 days of age; 353 infants completed the study through 365 days of age ( 110; LF-0.6: 127; LF-1.0: 116). Few differences in growth, formula intake, and infant fussiness or gassiness were observed through 365 day of age. Group discontinuation rates and the overall group incidence of medically-confirmed adverse events were not significantly different. From 30 through 180 days of age, group differences in stool consistency (P < 0.005) were detected with softer stools for infants in the LF-0.6 and LF-1.0 groups versus CONTROL. Compared to the Control, infants who received investigational formulas with bLf and the

Fatigue reliability of deck structures subjected to correlated crack growth

NASA Astrophysics Data System (ADS)

Feng, G. Q.; Garbatov, Y.; Guedes Soares, C.

2013-12-01

The objective of this work is to analyse fatigue reliability of deck structures subjected to correlated crack growth. The stress intensity factors of the correlated cracks are obtained by finite element analysis and based on which the geometry correction functions are derived. The Monte Carlo simulations are applied to predict the statistical descriptors of correlated cracks based on the Paris-Erdogan equation. A probabilistic model of crack growth as a function of time is used to analyse the fatigue reliability of deck structures accounting for the crack propagation correlation. A deck structure is modelled as a series system of stiffened panels, where a stiffened panel is regarded as a parallel system composed of plates and are longitudinal. It has been proven that the method developed here can be conveniently applied to perform the fatigue reliability assessment of structures subjected to correlated crack growth.

Thalamic structures and associated cognitive functions: Relations with age and aging.

PubMed

Fama, Rosemary; Sullivan, Edith V

2015-07-01

The thalamus, with its cortical, subcortical, and cerebellar connections, is a critical node in networks supporting cognitive functions known to decline in normal aging, including component processes of memory and executive functions of attention and information processing. The macrostructure, microstructure, and neural connectivity of the thalamus changes across the adult lifespan. Structural and functional magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) have demonstrated, regional thalamic volume shrinkage and microstructural degradation, with anterior regions generally more compromised than posterior regions. The integrity of selective thalamic nuclei and projections decline with advancing age, particularly those in thalamofrontal, thalamoparietal, and thalamolimbic networks. This review presents studies that assess the relations between age and aging and the structure, function, and connectivity of the thalamus and associated neural networks and focuses on their relations with processes of attention, speed of information processing, and working and episodic memory. Copyright © 2015 Elsevier Ltd. All rights reserved.

Structural Imaging Measures of Brain Aging

PubMed Central

Lockhart, Samuel N.

2014-01-01

During the course of normal aging, biological changes occur in the brain that are associated with changes in cognitive ability. This review presents data from neuroimaging studies of primarily “normal” or healthy brain aging. As such, we focus on research in unimpaired or nondemented older adults, but also include findings from lifespan studies that include younger and middle aged individuals as well as from populations with prodromal or clinically symptomatic disease such as cerebrovascular or Alzheimer’s disease. This review predominantly addresses structural MRI biomarkers, such as volumetric or thickness measures from anatomical images, and measures of white matter injury and integrity respectively from FLAIR or DTI, and includes complementary data from PET and cognitive or clinical testing as appropriate. The findings reveal highly consistent age-related differences in brain structure, particularly frontal lobe and medial temporal regions that are also accompanied by age-related differences in frontal and medial temporal lobe mediated cognitive abilities. Newer findings also suggest that degeneration of specific white matter tracts such as those passing through the genu and splenium of the corpus callosum may also be related to age-related differences in cognitive performance. Interpretation of these findings, however, must be tempered by the fact that comorbid diseases such as cerebrovascular and Alzheimer’s disease also increase in prevalence with advancing age. As such, this review discusses challenges related to interpretation of current theories of cognitive aging in light of the common occurrence of these later-life diseases. Understanding the differences between “Normal” and “Healthy” brain aging and identifying potential modifiable risk factors for brain aging is critical to inform potential treatments to stall or reverse the effects of brain aging and possibly extend cognitive health for our aging society. PMID:25146995

Structural imaging measures of brain aging.

PubMed

Lockhart, Samuel N; DeCarli, Charles

2014-09-01

During the course of normal aging, biological changes occur in the brain that are associated with changes in cognitive ability. This review presents data from neuroimaging studies of primarily "normal" or healthy brain aging. As such, we focus on research in unimpaired or nondemented older adults, but also include findings from lifespan studies that include younger and middle aged individuals as well as from populations with prodromal or clinically symptomatic disease such as cerebrovascular or Alzheimer's disease. This review predominantly addresses structural MRI biomarkers, such as volumetric or thickness measures from anatomical images, and measures of white matter injury and integrity respectively from FLAIR or DTI, and includes complementary data from PET and cognitive or clinical testing as appropriate. The findings reveal highly consistent age-related differences in brain structure, particularly frontal lobe and medial temporal regions that are also accompanied by age-related differences in frontal and medial temporal lobe mediated cognitive abilities. Newer findings also suggest that degeneration of specific white matter tracts such as those passing through the genu and splenium of the corpus callosum may also be related to age-related differences in cognitive performance. Interpretation of these findings, however, must be tempered by the fact that comorbid diseases such as cerebrovascular and Alzheimer's disease also increase in prevalence with advancing age. As such, this review discusses challenges related to interpretation of current theories of cognitive aging in light of the common occurrence of these later-life diseases. Understanding the differences between "Normal" and "Healthy" brain aging and identifying potential modifiable risk factors for brain aging is critical to inform potential treatments to stall or reverse the effects of brain aging and possibly extend cognitive health for our aging society.

Optimum temperature for growth and preferred temperatures of age-0 lake trout

USGS Publications Warehouse

Edsall, Thomas A.; Cleland, Joshua

2000-01-01

This study was performed to determine the thermal preferences and optimum temperature for growth of age-0 lake trout Salvelinus namaycush to help predict the thermal habitat they select when they leave the spawning grounds and to assess the risk posed to them in the Great Lakes by piscivorus, nonnative fishes whose thermal habitat preferences are known. The test fish were hatched in the laboratory from eggs taken from wild fish, acclimated to 5, 10, 15, and 18°C, and fed to excess with commercial trout food for 47 d. The test fish grew at all of the temperatures, and the specific growth rate was highest at about 12.5°C (3.8% wet body weight/d). Fish used in the growth study were also tested in a vertical thermal gradient tank and had a final thermal preferendum between 10.1°C and 10.2°C. These results, which generally agreed with those of an earlier laboratory study of the temperature preference of age-1 lake trout and the limited information on thermal habitat use by age-0 lake trout in the Great Lakes, indicated age-0 lake trout would tend to seek temperatures near 10°C, or as high as 12.5°C, during summer if food was abundant. Published information on thermal habitat use of age-1 and adult alewives Alosa pseudoharengus and rainbow smelt Osmerus mordax indicated they would be expected to co-occur with age-0 lake trout during much of the time when the lake trout were small enough to be eaten by these two introduced piscivores.

Age, size and regeneration of old growth white pine at Dividing Lake Nature Reserve, Algonquin Park, Ontario

Treesearch

Richard P. Guyette; Daniel C. Dey

1995-01-01

The age, mode of regeneration and diameter growth of white pine were determined in an old growth stand near Dividing Lake, Algonquin Provincial Park. The white pine ranged in age from 267 to 486 years. There was no significant relationship between white pine age and diameter (DBH). The distribution of tree ages indicated that the white pine component in this mixed...

Age and growth of the round stingray Urotrygon rogersi, a particularly fast-growing and short-lived elasmobranch.

PubMed

Mejía-Falla, Paola A; Cortés, Enric; Navia, Andrés F; Zapata, Fernando A

2014-01-01

We examined the age and growth of Urotrygon rogersi on the Colombian coast of the Eastern Tropical Pacific Ocean by directly estimating age using vertebral centra. We verified annual deposition of growth increments with marginal increment analysis. Eight growth curves were fitted to four data sets defined on the basis of the reproductive cycle (unadjusted or adjusted for age at first band) and size variables (disc width or total length). Model performance was evaluated using Akaike's Information Criterion (AIC), AIC weights and multi-model inference criteria. A two-phase growth function with adjusted age provided the best description of growth for females (based on five parameters, DW∞  =  20.1 cm, k  =  0.22 yr⁻¹) and males (based on four and five parameters, DW(∞)  =  15.5 cm, k  =  0.65 yr⁻¹). Median maturity of female and male U. rogersi is reached very fast (mean ± SE  =  1.0 ± 0.1 year). This is the first age and growth study for a species of the genus Urotrygon and results indicate that U. rogersi attains a smaller maximum size and has a shorter lifespan and lower median age at maturity than species of closely related genera. These life history traits are in contrast with those typically reported for other elasmobranchs.

Growth model for uneven-aged loblolly pine stands : simulations and management implications

Treesearch

C.-R. Lin; J. Buongiorno; Jeffrey P. Prestemon; K. E. Skog

1998-01-01

A density-dependent matrix growth model of uneven-aged loblolly pine stands was developed with data from 991 permanent plots in the southern United States. The model predicts the number of pine, soft hardwood, and hard hardwood trees in 13 diameter classes, based on equations for ingrowth, upgrowth, and mortality. Projections of 6 to 10 years agreed with the growth...

Individual-tree diameter growth model for managed, even-aged, upland oak stands

Treesearch

Donald E. Hilt

1983-01-01

A distance-independent, individual-tree diameter growth model was developed for managed, even-aged, upland oak stands. The 5-year basal-area growth of individual trees is first modeled as a function of dbh squared for given stands. Parameters from these models are then modeled as a function of mean stand diameter, percent stocking of the stand, and site index. A...

Decreased growth rate of P. falciparum blood stage parasitemia with age in a holoendemic population.

PubMed

Pinkevych, Mykola; Petravic, Janka; Chelimo, Kiprotich; Vulule, John; Kazura, James W; Moormann, Ann M; Davenport, Miles P

2014-04-01

In malaria holoendemic settings, decreased parasitemia and clinical disease is associated with age and cumulative exposure. The relative contribution of acquired immunity against various stages of the parasite life cycle is not well understood. In particular, it is not known whether changes in infection dynamics can be best explained by decreasing rates of infection, or by decreased growth rates of parasites in blood. Here, we analyze the dynamics of Plasmodium falciparum infection after treatment in a cohort of 197 healthy study participants of different ages. We use both polymerase chain reaction (PCR) and microscopy detection of parasitemia in order to understand parasite growth rates and infection rates over time. The more sensitive PCR assay detects parasites earlier than microscopy, and demonstrates a higher overall prevalence of infection than microscopy alone. The delay between PCR and microscopy detection is significantly longer in adults compared with children, consistent with slower parasite growth with age. We estimated the parasite multiplication rate from delay to PCR and microscopy detections of parasitemia. We find that both the delay between PCR and microscopy infection as well as the differing reinfection dynamics in different age groups are best explained by a slowing of parasite growth with age.

A structure-based extracellular matrix expansion mechanism of fibrous tissue growth.

PubMed

Kalson, Nicholas S; Lu, Yinhui; Taylor, Susan H; Starborg, Tobias; Holmes, David F; Kadler, Karl E

2015-05-20

Embryonic growth occurs predominately by an increase in cell number; little is known about growth mechanisms later in development when fibrous tissues account for the bulk of adult vertebrate mass. We present a model for fibrous tissue growth based on 3D-electron microscopy of mouse tendon. We show that the number of collagen fibrils increases during embryonic development and then remains constant during postnatal growth. Embryonic growth was explained predominately by increases in fibril number and length. Postnatal growth arose predominately from increases in fibril length and diameter. A helical crimp structure was established in embryogenesis, and persisted postnatally. The data support a model where the shape and size of tendon is determined by the number and position of embryonic fibroblasts. The collagen fibrils that these cells synthesise provide a template for postnatal growth by structure-based matrix expansion. The model has important implications for growth of other fibrous tissues and fibrosis.

A structure-based extracellular matrix expansion mechanism of fibrous tissue growth

PubMed Central

Kalson, Nicholas S; Lu, Yinhui; Taylor, Susan H; Starborg, Tobias; Holmes, David F; Kadler, Karl E

2015-01-01

Embryonic growth occurs predominately by an increase in cell number; little is known about growth mechanisms later in development when fibrous tissues account for the bulk of adult vertebrate mass. We present a model for fibrous tissue growth based on 3D-electron microscopy of mouse tendon. We show that the number of collagen fibrils increases during embryonic development and then remains constant during postnatal growth. Embryonic growth was explained predominately by increases in fibril number and length. Postnatal growth arose predominately from increases in fibril length and diameter. A helical crimp structure was established in embryogenesis, and persisted postnatally. The data support a model where the shape and size of tendon is determined by the number and position of embryonic fibroblasts. The collagen fibrils that these cells synthesise provide a template for postnatal growth by structure-based matrix expansion. The model has important implications for growth of other fibrous tissues and fibrosis. DOI: http://dx.doi.org/10.7554/eLife.05958.001 PMID:25992598

Histological changes in vocal fold growth and aging.

PubMed

Kuhn, Maggie A

2014-12-01

Sophisticated descriptions of the highly specialized vocal fold microarchitecture have been available for over three decades, but how this anatomy evolves with growth and aging remains an area of active investigation and, at times, a source of controversy. As our aging population expands and interest in pediatric voice disorders blossoms, it is timely to consider our contemporary understanding of evolving vocal fold histology and its implications for voice production. Novel applications of existing and emerging biotechnology, development of animal models and skillful use of human specimens have afforded greater insights into the histologic vocal fold changes seen throughout the lifespan in health and disease. Burgeoning knowledge has laid the foundation for more comprehensive models of vocal fold histology and has led to the development of innovative therapies for challenging voice disorders.

Travelling Wave Solutions in Multigroup Age-Structured Epidemic Models

NASA Astrophysics Data System (ADS)

Ducrot, Arnaut; Magal, Pierre; Ruan, Shigui

2010-01-01

Age-structured epidemic models have been used to describe either the age of individuals or the age of infection of certain diseases and to determine how these characteristics affect the outcomes and consequences of epidemiological processes. Most results on age-structured epidemic models focus on the existence, uniqueness, and convergence to disease equilibria of solutions. In this paper we investigate the existence of travelling wave solutions in a deterministic age-structured model describing the circulation of a disease within a population of multigroups. Individuals of each group are able to move with a random walk which is modelled by the classical Fickian diffusion and are classified into two subclasses, susceptible and infective. A susceptible individual in a given group can be crisscross infected by direct contact with infective individuals of possibly any group. This process of transmission can depend upon the age of the disease of infected individuals. The goal of this paper is to provide sufficient conditions that ensure the existence of travelling wave solutions for the age-structured epidemic model. The case of two population groups is numerically investigated which applies to the crisscross transmission of feline immunodeficiency virus (FIV) and some sexual transmission diseases.

Use of World Health Organization and CDC growth charts for children aged 0-59 months in the United States.

PubMed

Grummer-Strawn, Laurence M; Reinold, Chris; Krebs, Nancy F

2010-09-10

In April 2006, the World Health Organization (WHO) released new international growth charts for children aged 0-59 months. Similar to the 2000 CDC growth charts, these charts describe weight for age, length (or stature) for age, weight for length (or stature), and body mass index for age. Whereas the WHO charts are growth standards, describing the growth of healthy children in optimal conditions, the CDC charts are a growth reference, describing how certain children grew in a particular place and time. However, in practice, clinicians use growth charts as standards rather than references. In 2006, CDC, the National Institutes of Health, and the American Academy of Pediatrics convened an expert panel to review scientific evidence and discuss the potential use of the new WHO growth charts in clinical settings in the United States. On the basis of input from this expert panel, CDC recommends that clinicians in the United States use the 2006 WHO international growth charts, rather than the CDC growth charts, for children aged <24 months (available at https://www.cdc.gov/growthcharts). The CDC growth charts should continue to be used for the assessment of growth in persons aged 2--19 years. The recommendation to use the 2006 WHO international growth charts for children aged <24 months is based on several considerations, including the recognition that breastfeeding is the recommended standard for infant feeding. In the WHO charts, the healthy breastfed infant is intended to be the standard against which all other infants are compared; 100% of the reference population of infants were breastfed for 12 months and were predominantly breastfed for at least 4 months. When using the WHO growth charts to screen for possible abnormal or unhealthy growth, use of the 2.3rd and 97.7th percentiles (or ±2 standard deviations) are recommended, rather than the 5th and 95th percentiles. Clinicians should be aware that fewer U.S. children will be identified as underweight using the WHO

Postnatal growth and development in the preterm and small for gestational age infant.

PubMed

Cooke, Richard J

2010-01-01

A clear relationship exists between undernutrition, poorer growth and poor development in term and preterm infants. However, preterm infants are at greater risk than term infants. Undernutrition is more common and 'programmed' growth rates are almost six times faster. Thus, even short periods of nutritional deprivation may have significant effects. Recent advances have led to an improvement in early growth but very low birthweight infants remain small for gestational age at hospital discharge. Studies suggest that a 'window of opportunity' exists after hospital discharge, in that better growth between discharge and 2-3 months corrected age is paralleled by better development, and poorer growth is associated with poorer development. However, interventions aimed at improving growth and development have yielded varying results. This may partly be related to differences in study design as well as the composition of the nutrient-enriched formulas. Irrespective, one point is concerning, i.e. infant boys appear to be at a developmental disadvantage when fed a term infant formula after discharge. A single study has also suggested that dietary intervention can improve brain growth in term and preterm infants with perinatal brain injury. However, concern has been expressed about rapid 'catch-up' growth in preterm infants and the development of insulin resistance and visceral adiposity. Data from our group do not support the idea of increased or altered adiposity in preterm infants fed a nutrient-enriched formula after hospital discharge. Copyright (c) 2010 S. Karger AG, Basel.

Individual heterogeneity in growth and age at sexual maturity: A gamma process analysis of capture–mark–recapture data

USGS Publications Warehouse

Link, William; Hesed, Kyle Miller

2015-01-01

Knowledge of organisms’ growth rates and ages at sexual maturity is important for conservation efforts and a wide variety of studies in ecology and evolutionary biology. However, these life history parameters may be difficult to obtain from natural populations: individuals encountered may be of unknown age, information on age at sexual maturity may be uncertain and interval-censored, and growth data may include both individual heterogeneity and measurement errors. We analyzed mark–recapture data for Red-backed Salamanders (Plethodon cinereus) to compare sex-specific growth rates and ages at sexual maturity. Aging of individuals was made possible by the use of a von Bertalanffy model of growth, complemented with models for interval-censored and imperfect observations at sexual maturation. Individual heterogeneity in growth was modeled through the use of Gamma processes. Our analysis indicates that female P. cinereus mature earlier and grow more quickly than males, growing to nearly identical asymptotic size distributions as males.

China's marriage squeeze: A decomposition into age and sex structure.

PubMed

Jiang, Quanbao; Li, Xiaomin; Li, Shuzhuo; Feldman, Marcus W

2016-06-01

Most recent studies of marriage patterns in China have emphasized the male-biased sex ratio but have largely neglected age structure as a factor in China's male marriage squeeze. In this paper we develop an index we call "spousal sex ratio" (SSR) to measure the marriage squeeze, and a method of decomposing the proportion of male surplus into age and sex structure effects within a small spousal age difference interval. We project that China's marriage market will be confronted with a relatively severe male squeeze. For the decomposition of the cohort aged 30, from 2010 to 2020 age structure will be dominant, while from 2020 through 2034 the contribution of age structure will gradually decrease and that of sex structure will increase. From then on, sex structure will be dominant. The index and decomposition, concentrated on a specific female birth cohort, can distinguish spousal competition for single cohorts which may be covered by a summary index for the whole marriage market; these can also be used for consecutive cohorts to reflect the situation of the whole marriage market.

Growth pattern and age at menarche of obese girls in a transitional society.

PubMed

Jaruratanasirikul, S; Mo-suwan, L; Lebel, L

1997-01-01

Childhood obesity is an increasing problem in a transitional society such as Thailand. To study physical growth and puberty in obese children, a cross-sectional survey of growth and age at menarche was carried out in schoolgirls aged between 8 and 16 years old. The 3,120 girls were divided into two groups based on weight-for-height criteria. Girls with weight-for-height between 80 and 120% were classified as normal stature (2,625; 84.1%) and those more than 120% were obese (495; 15.9%). Using probit analysis, age at menarche in obese girls was 0.9 year earlier than normal stature girls (11.5 years vs 12.4 years). At age 12, obese girls were reaching menarche 2.8 times more when compared with the normal stature girls. In terms of growth pattern, obese girls were taller and grew faster during the prepubertal period, and then reached their final height earlier than the normal stature girls (13 years vs 15 years). The final height in obese girls was significantly shorter (153.0 cm and 155.0 cm, p = 0.01). We conclude that: 1) obese girls grow faster, have earlier menarche and then stop growing earlier, and 2) obese girls tend to be shorter as adults, compared with normal stature girls.

India's Proposed Universal Health Coverage Policy: Evidence for Age Structure Transition Effect and Fiscal Sustainability.

PubMed

Narayana, Muttur Ranganathan

2016-12-01

India's High Level Expert Group on Universal Health Coverage in 2011 recommended a universal, public-funded and national health coverage policy. As a plausible forward-looking macroeconomic reform in the health sector, this policy proposal on universal health coverage (UHC) needs to be evaluated for age structure transition effect and fiscal sustainability to strengthen its current design and future implementation. Macroeconomic analyses of the long-term implications of age structure transition and fiscal sustainability on India's proposed UHC policy. A new measure of age-specific UHC is developed by combining the age profile of public and private health consumption expenditure by using the National Transfer Accounts methodology. Different projections of age-specific public health expenditure are calculated over the period 2005-2100 to account for the age structure transition effect. The projections include changes in: (1) levels of the expenditure as gross domestic product grows, (2) levels and shape of the expenditure as gross domestic product grows and expenditure converges to that of developed countries (or convergence scenario) based on the Lee-Carter model of forecasting mortality rates, and (3) levels of the expenditure as India moves toward a UHC policy. Fiscal sustainability under each health expenditure projection is determined by using the measures of generational imbalance and sustainability gap in the Generational Accounting methodology. Public health expenditure is marked by age specificities and the elderly population is costlier to support for their healthcare needs in the future. Given the discount and productivity growth rates, the proposed UHC is not fiscally sustainable under India's current fiscal policies except for the convergence scenario. However, if the income elasticity of public expenditure on social welfare and health expenditure is less than one, fiscal sustainability of the UHC policy is attainable in all scenarios of projected public

Cost-effective age structure and geographical distribution of boreal forest reserves.

PubMed

Lundström, Johanna; Ohman, Karin; Perhans, Karin; Rönnqvist, Mikael; Gustafsson, Lena; Bugman, Harald

2011-02-01

1. Forest reserves are established to preserve biodiversity, and to maintain natural functions and processes. Today there is heightened focus on old-growth stages, with less attention given to early successional stages. The biodiversity potential of younger forests has been overlooked, and the cost-effectiveness of incorporating different age classes in reserve networks has not yet been studied.2. We performed a reserve selection analysis in boreal Sweden using the Swedish National Forest Inventory plots. Seventeen structural variables were used as biodiversity indicators, and the cost of protecting each plot as a reserve was assessed using the Heureka system. A goal programming approach was applied, which allowed inclusion of several objectives and avoided a situation in which common indicators affected the result more than rare ones. The model was limited either by budget or area.3. All biodiversity indicators were found in all age classes, with more than half having the highest values in ages ≥ 100 years. Several large-tree indicators and all deadwood indicators had higher values in forests 0-14 years than in forests 15-69 years.4. It was most cost-effective to protect a large proportion of young forests since they generally have a lower net present value compared to older forests, but still contain structures of importance for biodiversity. However, it was more area-effective to protect a large proportion of old forests since they have a higher biodiversity potential per area.5. The geographical distribution of reserves selected with the budget-constrained model was strongly biassed towards the north-western section of boreal Sweden, with a large proportion of young forest, whereas the area-constrained model focussed on the south-eastern section, with dominance by the oldest age class.6.Synthesis and applications. We show that young forests with large amounts of structures important to biodiversity such as dead wood and remnant trees are cheap and cost

Cost-effective age structure and geographical distribution of boreal forest reserves

PubMed Central

Lundström, Johanna; Öhman, Karin; Perhans, Karin; Rönnqvist, Mikael; Gustafsson, Lena; Bugman, Harald

2011-01-01

1. Forest reserves are established to preserve biodiversity, and to maintain natural functions and processes. Today there is heightened focus on old-growth stages, with less attention given to early successional stages. The biodiversity potential of younger forests has been overlooked, and the cost-effectiveness of incorporating different age classes in reserve networks has not yet been studied. 2. We performed a reserve selection analysis in boreal Sweden using the Swedish National Forest Inventory plots. Seventeen structural variables were used as biodiversity indicators, and the cost of protecting each plot as a reserve was assessed using the Heureka system. A goal programming approach was applied, which allowed inclusion of several objectives and avoided a situation in which common indicators affected the result more than rare ones. The model was limited either by budget or area. 3. All biodiversity indicators were found in all age classes, with more than half having the highest values in ages ≥ 100 years. Several large-tree indicators and all deadwood indicators had higher values in forests 0–14 years than in forests 15–69 years. 4. It was most cost-effective to protect a large proportion of young forests since they generally have a lower net present value compared to older forests, but still contain structures of importance for biodiversity. However, it was more area-effective to protect a large proportion of old forests since they have a higher biodiversity potential per area. 5. The geographical distribution of reserves selected with the budget-constrained model was strongly biassed towards the north-western section of boreal Sweden, with a large proportion of young forest, whereas the area-constrained model focussed on the south-eastern section, with dominance by the oldest age class. 6. Synthesis and applications. We show that young forests with large amounts of structures important to biodiversity such as dead wood and remnant trees are cheap and

Making the right moves: promoting smart growth and active aging in communities.

PubMed

Sykes, Kathleen E; Robinson, Kristen N

2014-01-01

This article describes an award program sponsored by the U.S. Environmental Protection Agency for excellence in smart growth and active aging. Having examined qualitative and quantitative data, we suggest that any community can foster changes to improve the health and well-being of its aging population. Diverse winners took unique paths to change their built environments and encourage physical activity. The policy changes undertaken by the award winners have both short- and long-term benefits that are important for persons of all ages, but especially for an aging society.

Predicting tree biomass growth in the temperate-boreal ecotone: is tree size, age, competition or climate response most important?

USGS Publications Warehouse

Foster, Jane R.; Finley, Andrew O.; D'Amato, Anthony W.; Bradford, John B.; Banerjee, Sudipto

2016-01-01

As global temperatures rise, variation in annual climate is also changing, with unknown consequences for forest biomes. Growing forests have the ability to capture atmospheric CO2and thereby slow rising CO2 concentrations. Forests’ ongoing ability to sequester C depends on how tree communities respond to changes in climate variation. Much of what we know about tree and forest response to climate variation comes from tree-ring records. Yet typical tree-ring datasets and models do not capture the diversity of climate responses that exist within and among trees and species. We address this issue using a model that estimates individual tree response to climate variables while accounting for variation in individuals’ size, age, competitive status, and spatially structured latent covariates. Our model allows for inference about variance within and among species. We quantify how variables influence aboveground biomass growth of individual trees from a representative sample of 15 northern or southern tree species growing in a transition zone between boreal and temperate biomes. Individual trees varied in their growth response to fluctuating mean annual temperature and summer moisture stress. The variation among individuals within a species was wider than mean differences among species. The effects of mean temperature and summer moisture stress interacted, such that warm years produced positive responses to summer moisture availability and cool years produced negative responses. As climate models project significant increases in annual temperatures, growth of species likeAcer saccharum, Quercus rubra, and Picea glauca will vary more in response to summer moisture stress than in the past. The magnitude of biomass growth variation in response to annual climate was 92–95% smaller than responses to tree size and age. This means that measuring or predicting the physical structure of current and future forests could tell us more about future C dynamics than growth

Predicting tree biomass growth in the temperate-boreal ecotone: Is tree size, age, competition, or climate response most important?

PubMed

Foster, Jane R; Finley, Andrew O; D'Amato, Anthony W; Bradford, John B; Banerjee, Sudipto

2016-06-01

As global temperatures rise, variation in annual climate is also changing, with unknown consequences for forest biomes. Growing forests have the ability to capture atmospheric CO2 and thereby slow rising CO2 concentrations. Forests' ongoing ability to sequester C depends on how tree communities respond to changes in climate variation. Much of what we know about tree and forest response to climate variation comes from tree-ring records. Yet typical tree-ring datasets and models do not capture the diversity of climate responses that exist within and among trees and species. We address this issue using a model that estimates individual tree response to climate variables while accounting for variation in individuals' size, age, competitive status, and spatially structured latent covariates. Our model allows for inference about variance within and among species. We quantify how variables influence aboveground biomass growth of individual trees from a representative sample of 15 northern or southern tree species growing in a transition zone between boreal and temperate biomes. Individual trees varied in their growth response to fluctuating mean annual temperature and summer moisture stress. The variation among individuals within a species was wider than mean differences among species. The effects of mean temperature and summer moisture stress interacted, such that warm years produced positive responses to summer moisture availability and cool years produced negative responses. As climate models project significant increases in annual temperatures, growth of species like Acer saccharum, Quercus rubra, and Picea glauca will vary more in response to summer moisture stress than in the past. The magnitude of biomass growth variation in response to annual climate was 92-95% smaller than responses to tree size and age. This means that measuring or predicting the physical structure of current and future forests could tell us more about future C dynamics than growth responses

Periods of Child Growth up to age 8 Years in Ethiopia, India, Peru and Vietnam: Key Distal Household and Community Factors

PubMed Central

Schott, Whitney B.; Crookston, Benjamin T.; Lundeen, Elizabeth A.; Stein, Aryeh D.; Behrman, Jere R.

2013-01-01

Recent research has demonstrated some growth recovery among children stunted in infancy. Less is known about key age ranges for such growth recovery, and what factors are correlates with this growth. This study characterized child growth up to age 1 year, and from ages 1 to 5 and 5 to 8 years controlling for initial height-for-age z-score (HAZ), and identified key distal household and community factors associated with these growth measures using longitudinal data on 7,266 children in the Young Lives (YL) study in Ethiopia, India, Peru and Vietnam. HAZ at about age 1 year and age in months predicted much of the variation in HAZ at age 5 years, but 40 to 71% was not predicted. Similarly, HAZ at age 5 years and age in months did not predict 26 to 47% of variation in HAZ at 8 years. Multiple regression analysis suggests that parental schooling, consumption, and mothers’ height are key correlates of HAZ at about age 1 and also are associated with unpredicted change in HAZ from ages 1 to 5 and 5 to 8 years, given initial HAZ. These results underline the importance of a child’s starting point in infancy in determining his or her growth, point to key distal household and community factors that may determine early growth in early life and subsequent growth recovery and growth failure, and indicate that these factors vary some by country, urban/rural designation, and child sex. PMID:23769211

Periods of child growth up to age 8 years in Ethiopia, India, Peru and Vietnam: key distal household and community factors.

PubMed

Schott, Whitney B; Crookston, Benjamin T; Lundeen, Elizabeth A; Stein, Aryeh D; Behrman, Jere R

2013-11-01

Recent research has demonstrated some growth recovery among children stunted in infancy. Less is known about key age ranges for such growth recovery, and what factors are correlates with this growth. This study characterized child growth up to age 1 year, and from ages 1 to 5 and 5 to 8 years controlling for initial height-for-age z-score (HAZ), and identified key distal household and community factors associated with these growth measures using longitudinal data on 7266 children in the Young Lives (YL) study in Ethiopia, India, Peru and Vietnam. HAZ at about age 1 year and age in months predicted much of the variation in HAZ at age 5 years, but 40-71% was not predicted. Similarly, HAZ at age 5 years and age in months did not predict 26-47% of variation in HAZ at 8 years. Multiple regression analysis suggests that parental schooling, consumption, and mothers' height are key correlates of HAZ at about age 1 and also are associated with unpredicted change in HAZ from ages 1 to 5 and 5 to 8 years, given initial HAZ. These results underline the importance of a child's starting point in infancy in determining his or her growth, point to key distal household and community factors that may determine early growth in early life and subsequent growth recovery and growth failure, and indicate that these factors vary some by country, urban/rural designation, and child sex. Copyright © 2013 Elsevier Ltd. All rights reserved.

Metabolic health of young adults who were born small for gestational age and treated with growth hormone, after cessation of growth hormone treatment: a 5-year longitudinal study.

PubMed

van der Steen, Manouk; Smeets, Carolina C J; Kerkhof, Gerthe F; Hokken-Koelega, Anita C S

2017-02-01

Growth hormone treatment reduces fat mass and insulin sensitivity and increases lean body mass. Data are only available for short-term longitudinal changes after cessation of growth hormone treatment in young adults born small for gestational age. We aimed to assess long-term changes over a 5-year period following cessation of growth hormone treatment. We did a longitudinal study of young adults born small for gestational age and previously treated with growth hormone. Individuals were followed up for 5 years after attainment of adult height, when growth hormone treatment was discontinued: assessments were done at cessation of growth hormone treatment and at 6 months, 2 years, and 5 years thereafter. Data 5 years after cessation of growth hormone were compared with untreated age-matched controls. We used dual-energy x-ray absorptiometry to assess body composition, and did frequently sampled intravenous glucose tolerance tests to assess insulin sensitivity, acute insulin response, and the disposition index (a measure of β-cell function). This study is registered with ISRCTN, numbers ISRCTN96883876 and ISRCTN65230311. Between April, 2004, and April, 2016, we followed up 199 young adults born small for gestational age and previously treated with growth hormone, during the 5 years after cessation of growth hormone treatment. Data at 5 years for these individuals were compared with those for 51 untreated adults born small for gestational age with short stature, 92 untreated adults born small for gestational age with spontaneous catch-up growth, and 142 adults born appropriate for gestational age and unexposed to growth hormone treatment. In young adults born small for gestational age and previously treated with growth hormone, 5 years after cessation of growth hormone treatment, there were increases in fat mass (estimated marginal mean 10·73 kg [95% CI 9·95-11·50] at cessation of treatment vs 16·12 kg [14·77-17·46] at 5 years; p<0·0001), trunk fat (5·34 kg [4�

Age structure and development in ASEAN and Japan: 1950-2015; a preliminary report.

PubMed

Campbell, B O

1982-01-01

An attempt was made to show that significant shifts in age composition have occurred and will occur in the ASEAN countries and Japan. Based on the key ratio, the ratio of the entering labor force population, 15-29, to the established labor force population, 30-64, and on the education and dependency burdence, the evidence supports that such shifts have occurred and will occur. Another goal was to trace the potential impact of these age structure changes on the economy and society of the ASEAN countries and Japan, assuming a set of hypothetical relations between age structure changes, as measured by the key ratio and various demographic, economic, and social outcomes. This was done for Indonesia, and the Indonesian "case study" suggests that past and future changes in age strucute could have led and could lead to wide swings or long waves in per capita incomes or the growth rate in per capita incomes, the skill and possible captial intensity of production, household formation rates, emigration and immigration rates, fertility rates, and suicide rates, and other indicators of social instability. Interesting conclusions also emerged from the analysis of education and dependency burdens, especially the inverse relation between Japan's and ASEAN's burdens on both indices. The low educational and dependency burdens Japan enjoyed must have given Japan a distinct advantage in providing resources for infrastrucute, plant, and equipment, and so forth--an advantage that Japan will maintain (joined by Singapore) over the rest of this century. It is entirely possible that the relative economic performance of Japan versus the ASEAN countries or the ASEAN countries versus one another could not be fully explained or adequately forecasted without considering the impact of age structure and changes in age structure. It seems unlikely that the past or future performance of these countries individually can be adequately understood or forecasted without considering the long swing

Pre-natal exposures to cocaine and alcohol and physical growth patterns to age 8 years

PubMed Central

Lumeng, Julie C.; Cabral, Howard J.; Gannon, Katherine; Heeren, Timothy; Frank, Deborah A.

2007-01-01

Two hundred and two primarily African American/Caribbean children (classified by maternal report and infant meconium as 38 heavier, 74 lighter and 89 not cocaine-exposed) were measured repeatedly from birth to age 8 years to assess whether there is an independent effect of prenatal cocaine exposure on physical growth patterns. Children with fetal alcohol syndrome identifiable at birth were excluded. At birth, cocaine and alcohol exposures were significantly and independently associated with lower weight, length and head circumference in cross-sectional multiple regression analyses. The relationship over time of pre-natal exposures to weight, height, and head circumference was then examined by multiple linear regression using mixed linear models including covariates: child’s gestational age, gender, ethnicity, age at assessment, current caregiver, birth mother’s use of alcohol, marijuana and tobacco during the pregnancy and pre-pregnancy weight (for child’s weight) and height (for child’s height and head circumference). The cocaine effects did not persist beyond infancy in piecewise linear mixed models, but a significant and independent negative effect of pre-natal alcohol exposure persisted for weight, height, and head circumference. Catch-up growth in cocaine-exposed infants occurred primarily by 6 months of age for all growth parameters, with some small fluctuations in growth rates in the preschool age range but no detectable differences between heavier versus unexposed nor lighter versus unexposed thereafter. PMID:17412558

Demographic analysis from summaries of an age-structured population

USGS Publications Warehouse

Link, William A.; Royle, J. Andrew; Hatfield, Jeff S.

2003-01-01

Demographic analyses of age-structured populations typically rely on life history data for individuals, or when individual animals are not identified, on information about the numbers of individuals in each age class through time. While it is usually difficult to determine the age class of a randomly encountered individual, it is often the case that the individual can be readily and reliably assigned to one of a set of age classes. For example, it is often possible to distinguish first-year from older birds. In such cases, the population age structure can be regarded as a latent variable governed by a process prior, and the data as summaries of this latent structure. In this article, we consider the problem of uncovering the latent structure and estimating process parameters from summaries of age class information. We present a demographic analysis for the critically endangered migratory population of whooping cranes (Grus americana), based only on counts of first-year birds and of older birds. We estimate age and year-specific survival rates. We address the controversial issue of whether management action on the breeding grounds has influenced recruitment, relating recruitment rates to the number of seventh-year and older birds, and examining the pattern of variation through time in this rate.

Tropical dendrochemistry: A novel approach to estimate age and growth from ringless trees

NASA Astrophysics Data System (ADS)

Poussart, P. M.; Myneni, S. C. B.; Lanzirotti, A.

2006-09-01

Although tropical forests play an active role in the global carbon cycle and climate, their growth history remains poorly characterized compared to other ecosystems on the planet. Trees are prime candidates for the extraction of paleoclimate archives as they can be probed sub-annually, are widely distributed and can live for over 1400 years [Chambers et al., 1998]. However, dendrochronological techniques have found limited applications in the tropics because trees often lack visible growth rings (Whitmore, 1990). Alternative methods exist (dendrometry (DaSilva et al., 2002), radio- and stable isotopes (Evans and Schrag, 2004; Poussart et al., 2004; Poussart and Schrag, 2005), but the derived records are either of short-duration, lack seasonal resolution or are prohibitively labor intensive to produce. Here, we show the first X-ray microprobe synchrotron record of calcium (Ca) from a ringless Miliusa velutina tree from Thailand and use it to estimate the tree's age and growth history. The Ca age model agrees within <=2 years of bomb-radiocarbon age estimates and confirms that the cycles are seasonal. The amplitude of the Ca annual cycle is correlated significantly with growth and annual Ca maxima correlate with the amount of dry season rainfall. Synchrotron measurements are fast and producing sufficient numbers of replicated multi-century tropical dendrochemical climate records now seems analytically feasible.

The age structure of selected countries in the ESCAP region.

PubMed

Hong, S

1982-01-01

The study objective was to examine the age structure of selected countries in the Economic and Social Commission for Asia and the Pacific (ESCAP) region, using available data and frequently applied indices such as the population pyramid, aged-child ratio, and median age. Based on the overall picture of the age structure thus obtained, age trends and their implication for the near future were arrived at. Countries are grouped into 4 types based on the fertility and mortality levels. Except for Japan, Hong Kong, and Singapore, the age structure in the 18 ESCAP region countries changed comparatively little over the 1950-80 period. The largest structural change occurred in Singapore, where the proportion of children under age 15 in the population declined significantly from 41-27%, while that of persons 65 years and older more than doubled. This was due primarily to the marked decline in fertility from a total fertility rate (TFR) of 6.7-1.8 during the period. Hong Kong also had a similar major transformation during the same period: the proportion of the old age population increased 2 1/2 times, from 2.5-6.3%. The age structures of the 18 ESCAP countries varied greatly by country. 10 countries of the 2 high fertility and mortality types showed a similar young age structural pattern, i.e., they have higher dependency ratios, a higher proportion of children under 15 years, a lower proportion of population 65 years and older, lower aged-child ratios, and younger median ages than the average countries in the less developed regions of the world. With minimal changes over the 1950-80 period, the gap between these countries and the average of the less developed regions widened. Unlike these 10 (mostly South Asian) countries, moderately low fertility and mortality countries (China, Korea, and Sri Lanka) are located between the world average and the less developed region in most of the indices, particularly during the last decade. Although their rate of population aging is not

Head circumference growth reference charts for Turkish children aged 0-84 months.

PubMed

Elmali, Ferhan; Altunay, Canan; Mazicioglu, Mümtaz M; Kondolot, Meda; Ozturk, Ahmet; Kurtoglu, Selim

2012-05-01

This study sought to produce updated head circumference references in a representative population of Turkish children aged 0 to <84 months. Head circumference measurements are very important in monitoring child growth, to evaluate macrocephaly and microcephaly. Primary sampling units involved family health centers in the city center and suburbs of Kayseri. In total, 2989 children (1479 boys and 1510 girls) were included. Head circumference was measured with a nonelastic tape on a line passing over the glabella and posterior occipital protrusion in children aged 0-2 years lying on a bed, and children aged more than 2 years standing up. We compared the 50th percentile of our cross-sectional data with longitudinal Belgian and American data. The comparison indicated that Turkish head circumference percentiles were similar to, or not much lower than, Belgian and American percentiles. Head circumference percentiles can be used to evaluate children with microcephaly and macrocephaly (±2 standard deviations), and to monitor growth. Copyright © 2012 Elsevier Inc. All rights reserved.

Mechanistic linkage of hydrologic regime to summer growth of age-0 Atlantic salmon

Treesearch

K.H. Nislow; A.J. Sepulveda; C.L. Folt

2004-01-01

Significant reductions in juvenile stream salmonid growth have been observed in association with low summer flow, but underlying mechanisms are poorly understood and predictive power is limited. We conducted a stage-specific analysis of the relationship between summer flow and the growth of age-0 Atlantic salmon Salmo salar in two rearing sites in...

The first description of oarfish Regalecus glesne (Regalecus russellii Cuvier 1816) ageing structures

USGS Publications Warehouse

Midway, S.R.; Wagner, Tyler

2016-01-01

Despite being a large, conspicuous teleost with a worldwide tropical and temperate distribution, the giant oarfish Regalecus spp. remain very rare fish species in terms of scientific sampling. Subsequently, very little biological information is known about Regalecus spp. and almost nothing has been concluded in the field of age and growth (Roberts, 2012). No studies of otoliths or temporal (annual) markings on any hard structures have been reported, and to our knowledge otoliths have never been recovered from any specimens (Tyson Roberts, personal communication),although a few texts do provide illustrations of Regalecus sp. otoliths (Lin and Chang, 2012; Nolf, 2013). Further inferential difficulty comes from the fact that age and growth studies of any Lampridiforme species are rare. Lampris guttatus is perhaps the only Lampridiforme species for which any biological information has been reported(Francis et al., 2004), which stems from the species commercial value. In order to begin understanding any species (for later purposes of management, conservation, etc.), basic biological information is needed. In the present study, we examine not only the first Regalecus russellii otolith, but provide suggestions toward future work that should direct data collection that can be used to generate basic biological information for this species.

Effects of size and age on the survival and growth of pulp and paper mills

Treesearch

Xiaolei Li; Joseph Buongiorno; Peter J. Ince

2004-01-01

The growth of pulp and paper mills in the US from 1970 to 2000 depended mostly on size and age. Mills grew according to Gibrat’s law, and post-1970 mills grew faster than pre-1971 mills. Mills stopped growing at approximately 22 years of age. But most mills survived beyond that, thus growth was not necessary for survival, but characteristic of the early phase of the...

Effect of Growth Hormone Deficiency on Brain Structure, Motor Function and Cognition

ERIC Educational Resources Information Center

Webb, Emma A.; O'Reilly, Michelle A.; Clayden, Jonathan D.; Seunarine, Kiran K.; Chong, Wui K.; Dale, Naomi; Salt, Alison; Clark, Chris A.; Dattani, Mehul T.

2012-01-01

The growth hormone-insulin-like growth factor-1 axis plays a role in normal brain growth but little is known of the effect of growth hormone deficiency on brain structure. Children with isolated growth hormone deficiency (peak growth hormone less than 6.7 [micro]g/l) and idiopathic short stature (peak growth hormone greater than 10 [micro]g/l)…

Perturbations in growth trajectory due to early diet affect age-related deterioration in performance.

PubMed

Lee, Who-Seung; Monaghan, Pat; Metcalfe, Neil B

2016-04-01

Fluctuations in early developmental conditions can cause changes in growth trajectories that subsequently affect the adult phenotype. Here, we investigated whether compensatory growth has long-term consequences for patterns of senescence.Using three-spined sticklebacks ( Gasterosteus aculeatus ), we show that a brief period of dietary manipulation in early life affected skeletal growth rate not only during the manipulation itself, but also during a subsequent compensatory phase when fish caught up in size with controls.However, this growth acceleration influenced swimming endurance and its decline over the course of the breeding season, with a faster decline in fish that had undergone faster growth compensation.Similarly, accelerated growth led to a more pronounced reduction in the breeding period (as indicated by the duration of sexual ornamentation) over the following two breeding seasons, suggesting faster reproductive senescence. Parallel experiments showed a heightened effect of accelerated growth on these age-related declines in performance if the fish were under greater time stress to complete their compensation prior to the breeding season.Compensatory growth led to a reduction in median life span of 12% compared to steadily growing controls. While life span was independent of the eventual adult size attained, it was negatively correlated with the age-related decline in swimming endurance and sexual ornamentation.These results, complementary to those found when growth trajectories were altered by temperature rather than dietary manipulations, show that the costs of accelerated growth can last well beyond the time over which growth rates differ and are affected by the time available until an approaching life-history event such as reproduction.

Fractional Dynamics of Network Growth Constrained by Aging Node Interactions

PubMed Central

Safdari, Hadiseh; Zare Kamali, Milad; Shirazi, Amirhossein; Khalighi, Moein; Jafari, Gholamreza; Ausloos, Marcel

2016-01-01

In many social complex systems, in which agents are linked by non-linear interactions, the history of events strongly influences the whole network dynamics. However, a class of “commonly accepted beliefs” seems rarely studied. In this paper, we examine how the growth process of a (social) network is influenced by past circumstances. In order to tackle this cause, we simply modify the well known preferential attachment mechanism by imposing a time dependent kernel function in the network evolution equation. This approach leads to a fractional order Barabási-Albert (BA) differential equation, generalizing the BA model. Our results show that, with passing time, an aging process is observed for the network dynamics. The aging process leads to a decay for the node degree values, thereby creating an opposing process to the preferential attachment mechanism. On one hand, based on the preferential attachment mechanism, nodes with a high degree are more likely to absorb links; but, on the other hand, a node’s age has a reduced chance for new connections. This competitive scenario allows an increased chance for younger members to become a hub. Simulations of such a network growth with aging constraint confirm the results found from solving the fractional BA equation. We also report, as an exemplary application, an investigation of the collaboration network between Hollywood movie actors. It is undubiously shown that a decay in the dynamics of their collaboration rate is found, even including a sex difference. Such findings suggest a widely universal application of the so generalized BA model. PMID:27171424

An Individual-Tree Growth and Yield Prediction System for Even-Aged Natural Shortleaf Pine Forests

Treesearch

Thomas B. Lynch; Kenneth L. Hitch; Michael M. Huebschmann; Paul A. Murphy

1999-01-01

The development of a system of equations that model the growth and development of even-aged natural shortleaf (Pinus echinata Mill.) pine forests is described. The growth prediction system is a distance-independent individual-tree simulator containing equations that predict basal-area growth, survival, total and merchantable heights, and total and...

Growth, structure, morphology, and magnetic properties of Ni ferrite films.

PubMed

Dong, Chunhui; Wang, Gaoxue; Guo, Dangwei; Jiang, Changjun; Xue, Desheng

2013-04-27

The morphology, structure, and magnetic properties of nickel ferrite (NiFe2O4) films fabricated by radio frequency magnetron sputtering on Si(111) substrate have been investigated as functions of film thickness. Prepared films that have not undergone post-annealing show the better spinel crystal structure with increasing growth time. Meanwhile, the size of grain also increases, which induces the change of magnetic properties: saturation magnetization increased and coercivity increased at first and then decreased. Note that the sample of 10-nm thickness is the superparamagnetic property. Transmission electron microscopy displays that the film grew with a disorder structure at initial growth, then forms spinel crystal structure as its thickness increases, which is relative to lattice matching between substrate Si and NiFe2O4.

Growth rate and age distribution of deep-sea black corals in the Gulf of Mexico

USGS Publications Warehouse

Prouty, N.G.; Roark, E.B.; Buster, N.A.; Ross, Steve W.

2011-01-01

Black corals (order Antipatharia) are important long-lived, habitat-forming, sessile, benthic suspension feeders that are found in all oceans and are usually found in water depths greater than 30 m. Deep-water black corals are some of the slowest-growing, longest-lived deep-sea corals known. Previous age dating of a limited number of black coral samples in the Gulf of Mexico focused on extrapolated ages and growth rates based on skeletal 210Pb dating. Our results greatly expand the age and growth rate data of black corals from the Gulf of Mexico. Radiocarbon analysis of the oldest Leiopathes sp. specimen from the upper De Soto Slope at 300 m water depth indicates that these animals have been growing continuously for at least the last 2 millennia, with growth rates ranging from 8 to 22 µm yr–1. Visual growth ring counts based on scanning electron microscopy images were in good agreement with the 14C-derived ages, suggestive of annual ring formation. The presence of bomb-derived 14C in the outermost samples confirms sinking particulate organic matter as the dominant carbon source and suggests a link between the deep-sea and surface ocean. There was a high degree of reproducibility found between multiple discs cut from the base of each specimen, as well as within duplicate subsamples. Robust 14C-derived chronologies and known surface ocean 14C reservoir age constraints in the Gulf of Mexico provided reliable calendar ages with future application to the development of proxy records.

Reassessment of spiny dogfish Squalus acanthias age and growth using vertebrae and dorsal-fin spines.

PubMed

Bubley, W J; Kneebone, J; Sulikowski, J A; Tsang, P C W

2012-04-01

Male and female spiny dogfish Squalus acanthias were collected in the western North Atlantic Ocean in the Gulf of Maine between July 2006 and June 2009. Squalus acanthias ranged from 25 to 102 cm stretch total length and were caught during all months of the year except January. Age estimates derived from banding patterns visible in both the vertebrae and second dorsal-fin spines were compared. Vertebral growth increments were visualized using a modified histological staining technique, which was verified as appropriate for obtaining age estimates. Marginal increment analysis of vertebrae verified the increment periodicity, suggesting annual band deposition. Based on increased precision and accuracy of age estimates, as well as more biologically realistic parameters generated in growth models, the current study found that vertebrae provided a more reliable and accurate means of estimating age in S. acanthias than the second dorsal-fin spine. Age estimates obtained from vertebrae ranged from <1 year-old to 17 years for male and 24 years for female S. acanthias. The two-parameter von Bertalanffy growth model fit to vertebrae-derived age estimates produced parameters of L∞ = 94·23 cm and k = 0·11 for males and L∞ = 100·76 cm and k = 0·12 for females. While these growth parameters differed from those previously reported for S. acanthias in the western North Atlantic Ocean, the causes of such differences were beyond the scope of the current study and remain to be determined. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

Age, growth and fall diet of channel catfish in Cheat Lake, West Virginia

USGS Publications Warehouse

Hilling, Corbin D.; Welsh, Stuart A.; Smith, Dustin M.

2016-01-01

Acidification has historically impaired Cheat Lake's fish community, but recent mitigation efforts within the Cheat River watershed have improved water quality and species richness. Presently, channel catfish Ictalurus punctatus are abundant and attain desirable sizes for anglers. We evaluated the age, growth, and fall diet of the population. We collected a sample of 155 channel catfish from Cheat Lake from 5 August to 4 December 2014, a subset of which we aged (n = 148) using lapillus otoliths. We fit four growth models (von Bertalanffy, logistic, Gompertz, and power) to length-at-age data and compared models using an information theoretic approach. We collected fall diets from 55 fish sampled from 13 October to 4 December 2014. Total lengths of individuals in the sample ranged from 154 to 721 mm and ages ranged from 2 to 19 y. We AICc-selected the von Bertalanffy growth model as the best approximating model, and the power and Gompertz models also had considerable support. Diets were numerically dominated by Diptera larvae, specifically Chironomidae and Chaoboridae, while 39% of stomachs contained terrestrial food items. This study provides baseline data for management of Cheat Lake's channel catfish population. Further, this study fills a knowledge gap in the scientific literature on channel catfish, because few previously published studies have examined the population ecology of channel catfish in the Central Appalachian region.

On the probabilistic structure of water age: Probabilistic Water Age

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porporato, Amilcare; Calabrese, Salvatore

We report the age distribution of water in hydrologic systems has received renewed interest recently, especially in relation to watershed response to rainfall inputs. The purpose of this contribution is first to draw attention to existing theories of age distributions in population dynamics, fluid mechanics and stochastic groundwater, and in particular to the McKendrick-von Foerster equation and its generalizations and solutions. A second and more important goal is to clarify that, when hydrologic fluxes are modeled by means of time-varying stochastic processes, the age distributions must themselves be treated as random functions. Once their probabilistic structure is obtained, it canmore » be used to characterize the variability of age distributions in real systems and thus help quantify the inherent uncertainty in the field determination of water age. Finally, we illustrate these concepts with reference to a stochastic storage model, which has been used as a minimalist model of soil moisture and streamflow dynamics.« less

On the probabilistic structure of water age: Probabilistic Water Age

DOE PAGES

Porporato, Amilcare; Calabrese, Salvatore

2015-04-23

We report the age distribution of water in hydrologic systems has received renewed interest recently, especially in relation to watershed response to rainfall inputs. The purpose of this contribution is first to draw attention to existing theories of age distributions in population dynamics, fluid mechanics and stochastic groundwater, and in particular to the McKendrick-von Foerster equation and its generalizations and solutions. A second and more important goal is to clarify that, when hydrologic fluxes are modeled by means of time-varying stochastic processes, the age distributions must themselves be treated as random functions. Once their probabilistic structure is obtained, it canmore » be used to characterize the variability of age distributions in real systems and thus help quantify the inherent uncertainty in the field determination of water age. Finally, we illustrate these concepts with reference to a stochastic storage model, which has been used as a minimalist model of soil moisture and streamflow dynamics.« less

Weight, Length, and Body Mass Index Growth of Children Under 2 Years of Age With Cleft Lip and Palate.

PubMed

Miranda, Gabriela Serrano; Marques, Ilza Lazarini; de Barros, Suely Prietto; Arena, Eliane Petean; de Souza, Luiz

2016-05-01

To study the growth of length-for-age (L/A), weight-for-age (W/A), and body mass index (BMI) of children with cleft lip and palate receiving a normal diet; to establish specific growth curves for children with cleft palate with or without cleft lip (CLP/ICP) who had not undergone palatoplasty and for children with isolated cleft lip (ICL); and to assess if CLP/ICP growth differed from ICL growth and if CLP/ICP and ICL growth differed from growth for typical children. Prospective and cross-sectional study. Hospital for Rehabilitation of Craniofacial Anomalies, Bauru, São Paulo, Brazil. Weight and length of 381 children with cleft lip and palate and who were younger than 2 years were recorded and used to calculate W/A, L/A, and BMI growth curves. The 2006 World Health Organization growth charts were used as a reference for typical children. All children received a normal diet for age. Children with CLP/ICP had median W/A and BMI growth curves below growth curves for typical children but showed spontaneous recovery starting at approximately 5 months of age, even with nonoperated cleft palate. Children with ICL had growth similar to that of typical children. Children with CLP/ICP, who initially had W/A and BMI values less than those of the ICL group, had W/A and BMI equal to or higher than the ICL group after 9 months of age. Children with CLP/ICP had impaired W/A and BMI growth with spontaneous recovery starting early in childhood. This study established specific W/A, BMI, and L/A growth curves for children with cleft lip and palate.

The consequences of fetal growth restriction on brain structure and neurodevelopmental outcome.

PubMed

Miller, Suzanne L; Huppi, Petra S; Mallard, Carina

2016-02-15

Fetal growth restriction (FGR) is a significant complication of pregnancy describing a fetus that does not grow to full potential due to pathological compromise. FGR affects 3-9% of pregnancies in high-income countries, and is a leading cause of perinatal mortality and morbidity. Placental insufficiency is the principal cause of FGR, resulting in chronic fetal hypoxia. This hypoxia induces a fetal adaptive response of cardiac output redistribution to favour vital organs, including the brain, and is in consequence called brain sparing. Despite this, it is now apparent that brain sparing does not ensure normal brain development in growth-restricted fetuses. In this review we have brought together available evidence from human and experimental animal studies to describe the complex changes in brain structure and function that occur as a consequence of FGR. In both humans and animals, neurodevelopmental outcomes are influenced by the timing of the onset of FGR, the severity of FGR, and gestational age at delivery. FGR is broadly associated with reduced total brain volume and altered cortical volume and structure, decreased total number of cells and myelination deficits. Brain connectivity is also impaired, evidenced by neuronal migration deficits, reduced dendritic processes, and less efficient networks with decreased long-range connections. Subsequent to these structural alterations, short- and long-term functional consequences have been described in school children who had FGR, most commonly including problems in motor skills, cognition, memory and neuropsychological dysfunctions. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Population age structure and asset returns: an empirical investigation.

PubMed

Poterba, J M

1998-10-01

"This paper investigates the association between population age structure, particularly the share of the population in the 'prime saving years' 45-60, and the returns on stocks and bonds. The paper is motivated by the claim that the aging of the 'Baby Boom' cohort in the United States is a key factor in explaining the recent rise in asset values. It also addresses the associated claim that asset prices will decline when this large cohort reaches retirement age and begins to reduce its asset holdings. This paper begins by considering household age-asset accumulation profiles. Data from the Survey of Consumer Finances suggest that while cross-sectional age-wealth profiles peak for households in their early 60s, cohort data on the asset ownership of the same households show a much less pronounced peak.... The paper then considers the historical relationship between demographic structure and real returns on Treasury bills, long-term government bonds, and corporate stock. The results do not suggest any robust relationship between demographic structure and asset returns.... The paper concludes by discussing factors such as international capital flows and forward-looking behavior on the part of market participants that could weaken the relationship between age structure and asset returns in a single nation." excerpt

Growth, size and age at maturity of the agile frog (Rana dalmatina) in an Iberian Peninsula population.

PubMed

Sarasola-Puente, Vanessa; Gosá, Alberto; Oromí, Neus; Madeira, María José; Lizana, Miguel

2011-06-01

The mean age of a population of agile frogs (Rana dalmatina) from the Iberian Peninsula was estimated using mark and recapture and skeletochronology. Life-history parameters, including growth rate, body length, age and size at maturity, sexual dimorphism and longevity, were studied. The regression between age and snout-vent length (SVL) was highly significant in both sexes. Males reached sexual maturity at two years of age, although sometimes they can reach it at only one year of age. The average SVL at maturity was 51.75 mm (standard error (SE)=0.71; n=45). Females reached sexual maturity at two years of age with an average SVL of 62.14 mm (SE=2.20; n=14). A subset of the female population reached sexual maturity at three years of age. Growth was rapid until sexual maturity was reached. There was an overlap of SVL between different age classes. Growth was continuous, fulfilling the conditions of Von Bertalanffy's model. The growth coefficient (K) was 0.840 in males and 0.625 in females. The maximum SVL was greater in females (73.00 mm) than in males (59.50mm). Sexual dimorphism was significantly biased towards females in all age classes. The maximum longevity observed was 6 years in females and 8 years in males. Management strategies for agile frogs should take into account factors such as these life-history characteristics. Copyright © 2011 Elsevier GmbH. All rights reserved.

Age and growth of round gobies in Lake Michigan, with preliminary mortality estimation

USGS Publications Warehouse

Huo, Bin; Madenjian, Charles P.; Xie, Cong X.; Zhao, Yingming; O'Brien, Timothy P.; Czesny, Sergiusz J.

2015-01-01

The round goby (Neogobius melanostomus) is a prevalent invasive species throughout Lake Michigan, as well as other Laurentian Great Lakes, yet little information is available on spatial variation in round goby growth within one body of water. Age and growth of round goby at three areas of Lake Michigan were studied by otolith analysis from a sample of 659 specimens collected from 2008 to 2012. Total length (TL) ranged from 48 to 131 mm for Sturgeon Bay, from 50 to 125 mm for Waukegan, and from 54 to 129 mm for Sleeping Bear Dunes. Ages ranged from 2 to 7 years for Sturgeon Bay, from 2 to 5 years for Waukegan, and from 2 to 6 years for Sleeping Bear Dunes. Area-specific and sex-specific body–otolith relationships were used to back-calculate estimates of total length at age, which were fitted to von Bertalanffy models to estimate growth rates. For both sexes, round gobies at Sleeping Bear Dunes and Waukegan grew significantly faster than those at Sturgeon Bay. However, round goby growth did not significantly differ between Sleeping Bear Dunes and Waukegan for either sex. At all three areas of Lake Michigan, males grew significantly faster than females. Based on catch curve analysis, estimates of annual mortality rates ranged from 0.79 to 0.84. These relatively high mortality rates suggested that round gobies may be under predatory control in Lake Michigan.

Age, growth, and reproductive biology of three catostomids from the Apalachicola River, Florida

USGS Publications Warehouse

Grabowski, Timothy B.; Young, S.P.; Isely, J.J.; Ely, Patrick C.

2012-01-01

Riverine catostomids can show a wide range of interspecific variation in life-history characteristics. Understanding these differences is an important consideration in evaluating the sensitivity of these fishes to disturbance and in formulating effective conservation strategies, particularly when dealing with an assemblage consisting of multiple species within a watershed. We collected Apalachicola redhorse Moxostoma n. sp. cf. poecilurum (n = 125), spotted sucker Minytrema melanops (n = 94), and quillback Carpiodes cyprinus (n = 94) to determine age, growth, and reproductive biology of spawning catostomids in the Apalachicola River, Florida, during 2007. Quillback was the smallest in total length at age; longest-lived; most fecund; and produced the smallest eggs. Apalachicola redhorse was the largest in body size; had an intermediate life span; and produced the fewest yet largest eggs. Spotted sucker was more similar to Apalachicola redhorse in most characteristics. Growth during ages 1-3 in all three species seemed to be negatively related to the proportion of observations of extreme flow, both high (Q90) and low (Q10), per year and a positive response in growth rate to high flows (>Q75 but < Q90). However, Apalachicola redhorse and spotted sucker growth was more sensitive to flow conditions than that of quillback. Our results suggest the life histories and ecological response of Apalachicola River catostomids to flow regulation are important components for developing strategies that incorporate the needs of these fishery resources into an ecosystem-based management approach.

Non-structural carbon dynamics and allocation relate to growth rate and leaf habit in California oaks.

PubMed

Trumbore, Susan; Czimczik, Claudia I; Sierra, Carlos A; Muhr, Jan; Xu, Xiaomei

2015-11-01

Trees contain non-structural carbon (NSC), but it is unclear for how long these reserves are stored and to what degree they are used to support plant activity. We used radiocarbon ((14)C) to show that the carbon (C) in stemwood NSC can achieve ages of several decades in California oaks. We separated NSC into two fractions: soluble (∼50% sugars) and insoluble (mostly starch) NSC. Soluble NSC contained more C than insoluble NSC, but we found no consistent trend in the amount of either pool with depth in the stem. There was no systematic difference in C age between the two fractions, although ages increased with stem depth. The C in both NSC fractions was consistently younger than the structural C from which they were extracted. Together, these results indicate considerable inward mixing of NSC within the stem and rapid exchange between soluble and insoluble pools, compared with the timescale of inward mixing. We observed similar patterns in sympatric evergreen and deciduous oaks and the largest differences among tree stems with different growth rates. The (14)C signature of carbon dioxide (CO2) emitted from tree stems was higher than expected from very recent photoassimilates, indicating that the mean age of C in respiration substrates included a contribution from C fixed years previously. A simple model that tracks NSC produced each year, followed by loss (through conversion to CO2) in subsequent years, matches our observations of inward mixing of NSC in the stem and higher (14)C signature of stem CO2 efflux. Together, these data support the idea of continuous accumulation of NSC in stemwood and that 'vigor' (growth rate) and leaf habit (deciduous vs evergreen) control NSC pool size and allocation. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Functional and Structural Optimality in Plant Growth: A Crop Modelling Case Study

NASA Astrophysics Data System (ADS)

Caldararu, S.; Purves, D. W.; Smith, M. J.

2014-12-01

Simple mechanistic models of vegetation processes are essential both to our understanding of plant behaviour and to our ability to predict future changes in vegetation. One concept that can take us closer to such models is that of plant optimality, the hypothesis that plants aim to achieve an optimal state. Conceptually, plant optimality can be either structural or functional optimality. A structural constraint would mean that plants aim to achieve a certain structural characteristic such as an allometric relationship or nutrient content that allows optimal function. A functional condition refers to plants achieving optimal functionality, in most cases by maximising carbon gain. Functional optimality conditions are applied on shorter time scales and lead to higher plasticity, making plants more adaptable to changes in their environment. In contrast, structural constraints are optimal given the specific environmental conditions that plants are adapted to and offer less flexibility. We exemplify these concepts using a simple model of crop growth. The model represents annual cycles of growth from sowing date to harvest, including both vegetative and reproductive growth and phenology. Structural constraints to growth are represented as an optimal C:N ratio in all plant organs, which drives allocation throughout the vegetative growing stage. Reproductive phenology - i.e. the onset of flowering and grain filling - is determined by a functional optimality condition in the form of maximising final seed mass, so that vegetative growth stops when the plant reaches maximum nitrogen or carbon uptake. We investigate the plants' response to variations in environmental conditions within these two optimality constraints and show that final yield is most affected by changes during vegetative growth which affect the structural constraint.

Growth mechanism and internal structure of vertically aligned single-walled carbon nanotubes.

PubMed

Einarsson, Erik; Kadowaki, Masayuki; Ogura, Kazuaki; Okawa, Jun; Xiang, Rong; Zhang, Zhengyi; Yamamoto, Takahisa; Ikuhara, Yuichi; Maruyama, Shigeo

2008-11-01

An in situ optical absorbance technique was used to monitor the growth of vertically aligned single-walled carbon nanotubes (VA-SWNTs) at various temperatures and pressures. The effects of the growth temperature and ethanol pressure on the initial growth rate and catalyst lifetime were investigated. It was found that the ideal pressure for VA-SWNT synthesis changes with the growth temperature, shifting toward higher pressure as the growth temperature increases. It was also found that the growth reaction is first-order below this ideal pressure. Additionally, the internal structure of the VA-SWNT film was observed at different depths into the film by transmission electron microscopy. The absence of large bundles was confirmed, and little change in the structure was observed to a depth of approximately 1 microm.

For Debate: Growth Hormone Treatment of Infants Born Small for Gestational Age should be Started at or before the First Year of Age.

PubMed

Laron, Zvi; Laron-Kenet, Tamar; Klinger, Gil

2016-12-01

Children born small for gestational age without early catch-up of somatic growth and head circumference subsequently remain short and suffer from various degrees of neurocognitive and psychological impairment. Based upon the role of growth hormone (GH) and insulin-like growth factor-I on early brain growth and maturation, we propose that GH treatment of these infants be instituted prior to their 2nd birthday. Copyright© of YS Medical Media ltd.

Shape-related characteristics of age-related differences in subcortical structures.

PubMed

Madan, Christopher R

2018-01-11

With an increasing aging population, it is important to understand biological markers of aging. Subcortical volume is known to differ with age; additionally considering shape-related characteristics may provide a better index of age-related differences. Fractal dimensionality is more sensitive to age-related differences, but is borne out of mathematical principles, rather than neurobiological relevance. We considered four distinct measures of shape and how they relate to aging and fractal dimensionality: surface-to-volume ratio, sphericity, long-axis curvature, and surface texture. Structural MRIs from a combined sample of over 600 healthy adults were used to measure age-related differences in the structure of the thalamus, putamen, caudate, and hippocampus. For each, volume and fractal dimensionality were calculated, as well as four distinct shape measures. These measures were examined for their utility in explaining age-related variability in brain structure. The four shape measures were able to account for 80%-90% of the variance in fractal dimensionality. Of the distinct shape measures, surface-to-volume ratio was the most sensitive biomarker. Though volume is often used to characterize inter-individual differences in subcortical structures, our results demonstrate that additional measures can be useful complements. Our results indicate that shape characteristics are useful biological markers of aging.

Growth, structure, morphology, and magnetic properties of Ni ferrite films

PubMed Central

2013-01-01

The morphology, structure, and magnetic properties of nickel ferrite (NiFe2O4) films fabricated by radio frequency magnetron sputtering on Si(111) substrate have been investigated as functions of film thickness. Prepared films that have not undergone post-annealing show the better spinel crystal structure with increasing growth time. Meanwhile, the size of grain also increases, which induces the change of magnetic properties: saturation magnetization increased and coercivity increased at first and then decreased. Note that the sample of 10-nm thickness is the superparamagnetic property. Transmission electron microscopy displays that the film grew with a disorder structure at initial growth, then forms spinel crystal structure as its thickness increases, which is relative to lattice matching between substrate Si and NiFe2O4. PMID:23622034

An Individual-Tree Growth and Yield Prediction System for Uneven-Aged Shortleaf Pine Stands

Treesearch

Michael M. Huebschmann; Lawrence R. Gering; Thomas B. Lynch; Onesphore Bitoki; Paul A. Murphy

2000-01-01

A system of equations modeling the growth and development of uneven-aged shortleaf pine (Pinus echinata Mill.) stands is described. The prediction system consists of two main components: (1) a distance-independent, individual-tree simulator containing equations that forecast ingrowth, basal-area growth, probability of survival, total and...

OAKSIM: An individual-tree growth and yield simulator for managed, even-aged, upland oak stands

Treesearch

Donald E. Hilt; Donald E. Hilt

1985-01-01

OAKSIM is an individual-tree growth and yield simulator for managed, even-aged, upland oak stands. Growth and yield projections for various thinning alternatives can be made with OAKSIM for a period of up to 50 years. Simulator components include an individual-tree diameter growth model, a mortality model, height prediction equations, bark ratio equations, a taper-...

Age determinations and growth rates of Pacific ferromanganese deposits using strontium isotopes

USGS Publications Warehouse

Ingram, B.L.; Hein, J.R.; Farmer, G.L.

1990-01-01

87Sr 86Sr ratios, trace element and REE compositions, and textural characteristics were determined for three hydrogenetic Fe-Mn crusts, one hydrothermal deposit, and two mixed hydrothermalhydrogenetic crusts from the Pacific. The Sr isotope data are compared to the Sr seawater curve for the Cenozoic to determine the ages and growth rates of the crusts. The 87Sr 86Sr in the crusts does not increase monotonically with depth as expected if the Sr were solely derived from seawater and perfectly preserved since deposition. This indicates post-depositional exchange of Sr or heterogeneous sources for the Sr originally contained in the crusts. Textures of hydrogenetic crusts generally correlate with Sr isotopic variations. The highest porosity intervals commonly exhibit the highest 87Sr 86Sr ratios, indicating exchange with younger seawater. Intervals with the lowest porosity commonly have lower 87Sr 86Sr and may preserve the original Sr isotopic ratios. Minimum ages of crust growth inception were calculated from dense, low porosity intervals. Growth of the hydrogenetic crusts began at or after 23 Ma, although their substrates are Cretaceous. Estimated average growth rates of the three hydrogenetic crusts vary between 0.9 and 2.7 mm/Ma, consistent with published rates determined by other techniques. Within the Marshall Islands crust, growth rates for individual layers varied greatly between 1.0 and 5.4 mm/Ma. For one crust, very low 87Sr 86Sr ratios occurred in detrital-rich intervals. Hydrothermal Fe-Mn oxide from the active Lau Basin back-arc spreading axis (Valu Fa Ridge) has an 87Sr 86Sr ratio with a predominantly seawater signature ( 87Sr 86Sr 0.709196), indicating a maximum age of 0.9 Ma. One crust from an off-axis seamount west of Gorda Ridge may have begun precipitating hydrogenetically at 0.5 Ma (0.709211), and had increasing hydrothermal or volcanic input in the top half of the crust, indicated by a significantly lower 87Sr 86Sr ratio (0.709052). ?? 1990.

Mathematical modelling of the growth of human fetus anatomical structures.

PubMed

Dudek, Krzysztof; Kędzia, Wojciech; Kędzia, Emilia; Kędzia, Alicja; Derkowski, Wojciech

2017-09-01

The goal of this study was to present a procedure that would enable mathematical analysis of the increase of linear sizes of human anatomical structures, estimate mathematical model parameters and evaluate their adequacy. Section material consisted of 67 foetuses-rectus abdominis muscle and 75 foetuses- biceps femoris muscle. The following methods were incorporated to the study: preparation and anthropologic methods, image digital acquisition, Image J computer system measurements and statistical analysis method. We used an anthropologic method based on age determination with the use of crown-rump length-CRL (V-TUB) by Scammon and Calkins. The choice of mathematical function should be based on a real course of the curve presenting growth of anatomical structure linear size Ύ in subsequent weeks t of pregnancy. Size changes can be described with a segmental-linear model or one-function model with accuracy adequate enough for clinical purposes. The interdependence of size-age is described with many functions. However, the following functions are most often considered: linear, polynomial, spline, logarithmic, power, exponential, power-exponential, log-logistic I and II, Gompertz's I and II and von Bertalanffy's function. With the use of the procedures described above, mathematical models parameters were assessed for V-PL (the total length of body) and CRL body length increases, rectus abdominis total length h, its segments hI, hII, hIII, hIV, as well as biceps femoris length and width of long head (LHL and LHW) and of short head (SHL and SHW). The best adjustments to measurement results were observed in the exponential and Gompertz's models.

The effects of own fetal growth on reported hypertension in parous women aged 33.

PubMed

Hennessy, E; Alberman, E

1997-06-01

Data from the study of the British 1958 birth cohort, National Child Development Study (NCDS), has allowed wider investigation of the relationship between retarded fetal growth and risk of adult hypertension. A history of self-reported hypertension was related to fetal growth in 3308 parous cohort members. Fetal growth, the measure used, is the difference in actual birthweight from that expected for the gestational age and subsequent adult height. The relationships were investigated both linearly and non-linearly adjusting for potential confounders. After adjustment for confounding factors, including adult weight for height, retarded fetal growth was associated with reported hypertension particularly when not confined to pregnancy. The latter was also associated with accelerated fetal growth, moderate or severe hypertension in the mother when pregnant with the cohort member, being relatively taller than your mother, and lack of educational qualifications. Hypertension confined to pregnancy was more likely among women who were themselves firstborn or older at childbirth. Neither maternal smoking during cohort's gestation nor cohort member's gestational age had a significant effect. The results are consistent with previous reports that fetal growth effects are less marked if gestation is short. The relationships between fetal growth and subsequent hypertension are extremely complex and variable, and need to be studied allowing for deviations from growth potential. Adult weight for height remains the strongest predictor of hypertension. The results suggest that losing weight is likely to have the same proportional benefit in women with and without a history of retarded fetal growth.

Control of growth of juvenile leaves of Eucalyptus globulus: effects of leaf age.

PubMed

Metcalfe, J C; Davies, W J; Pereira, J S

1991-12-01

Biophysical variables influencing the expansion of plant cells (yield threshold, cell wall extensibility and turgor) were measured in individual Eucalyptus globulus leaves from the time of emergence until cessation of growth. Leaf water relations variables and growth rates were determined as relative humidity was changed on an hourly basis. Yield threshold and cell wall extensibility were estimated from plots of leaf growth rate versus turgor. Cell wall extensibility was also measured by the Instron technique, and yield threshold was determined experimentally both by stress relaxation in a psychrometer chamber and by incubation in a range of polyethylene glycol solutions. Once emerging leaves reached approximately 5 cm(2) in size, increases in leaf area were rapid throughout the expansive phase and varied little between light and dark periods. Both leaf growth rate and turgor were sensitive to changes in humidity, and in the longer term, both yield threshold and cell wall extensibility changed as the leaf aged. Rapidly expanding leaves had a very low yield threshold and high cell wall extensibility, whereas mature leaves had low cell wall extensibility. Yield threshold increased with leaf age.

Femoral head epiphysis growth and development among Chinese children aged 0-5 years.

PubMed

Luo, Jiayou; Tang, Jin; Zhou, Libo; Zeng, Rong; Mou, Jinsong; Zhang, Lingli

2009-05-01

The aim of this study was to examine the pattern of femoral head epiphysis growth and development among Chinese children. Between January and December, 2007, we randomly sampled 1,450 healthy Chinese children (0-5 years old) from Hunan Provincial Children's Hospital in Changsha, Hunan, China. The diameter of femoral head epiphysis was measured by pelvic X-ray photography and processed by medical image processing software. The growth of femoral head epiphysis in girls was 2-3 months earlier than that in boys. The diameter of femoral head epiphysis increased with advancing age in both girls and boys, but the diameter of femoral head epiphysis in 2, 3, 4, 6, and 10-month-old girls was significantly larger than that in boys. Cubic regression equations between the diameter of femoral head epiphysis and age were created for boys and girls that could be used to predict the diameter of femoral head epiphysis. In conclusion, there was gender difference in femoral head epiphysis growth and development among Chinese children, and our prediction models will provide the guidance for early diagnosis of diseases related to the growth and development of the femoral head epiphysis.

An analysis of dental development in Pleistocene Homo using skeletal growth and chronological age.

PubMed

Šešelj, Maja

2017-07-01

This study takes a new approach to interpreting dental development in Pleistocene Homo in comparison with recent modern humans. As rates of dental development and skeletal growth are correlated given age in modern humans, using age and skeletal growth in tandem yields more accurate dental development estimates. Here, I apply these models to fossil Homo to obtain more individualized predictions and interpretations of their dental development relative to recent modern humans. Proportional odds logistic regression models based on three recent modern human samples (N = 181) were used to predict permanent mandibular tooth development scores in five Pleistocene subadults: Homo erectus/ergaster, Neanderthals, and anatomically modern humans (AMHs). Explanatory variables include a skeletal growth indicator (i.e., diaphyseal femoral length), and chronological age. AMHs Lagar Velho 1 and Qafzeh 10 share delayed incisor development, but exhibit considerable idiosyncratic variation within and across tooth types, relative to each other and to the reference samples. Neanderthals Dederiyeh 1 and Le Moustier 1 exhibit delayed incisor coupled with advanced molar development, but differences are reduced when femoral diaphysis length is considered. Dental development in KNM-WT 15,000 Homo erectus/ergaster, while advanced for his age, almost exactly matches the predictions once femoral length is included in the models. This study provides a new interpretation of dental development in KNM-WT 15000 as primarily reflecting his faster rates of skeletal growth. While the two AMH specimens exhibit considerable individual variation, the Neanderthals exhibit delayed incisor development early and advanced molar development later in ontogeny. © 2017 Wiley Periodicals, Inc.

Infant growth during the first year of life and subsequent hospitalization to 8 years of age.

PubMed

Hui, L L; Schooling, C Mary; Wong, M Y; Ho, L M; Lam, T H; Leung, Gabriel M

2010-05-01

There is accumulating evidence that rapid infant growth is associated with subsequent metabolic risk, but less investigation of potential benefits. We tested the life history trade-off hypothesis that rapid infant growth is associated with lower risk of serious childhood morbidity (in particular, infection) proxied by hospital admission. We studied term births (n = 7833, 94% follow-up) from a Chinese birth cohort, "Children of 1997," comprising 88% of births in Hong Kong in April and May 1997. We used multivariable negative binomial regression to examine the association of growth trajectory (5 categories) from birth to 12 months with subsequent hospital admissions until the child's 8th birthday. Potential confounders included sex, gestational age, parental education, type of birth hospital, infant feeding, and the presence of congenital disease. Infants with the slowest growth trajectory (smallest birth weight and slowest weight gain) were more likely to be hospitalized between 1 and 8 years of age-particularly for noninfectious illnesses. Infants in the 4 faster growth trajectories differed little in their risk of hospitalization. Adjusted incident rate ratios of hospitalization for infectious diseases were 0.93 (95% confidence interval = 0.81-1.06), 0.97 (0.85-1.12), 0.91 (0.78-1.06), and 0.92 (0.79-1.08) for the 4 faster growth trajectories compared with the slowest. Results were similar when growth was assessed as change in weight-for-age z-score. Fast infant growth does not protect against serious infectious morbidity, but low birth weight infants born with slow growth are more vulnerable to serious morbidity, either as a consequence of poor growth or as a parallel marker of underlying health state. Whether maximum growth rates are ideal should be considered, as should the effects of infant over-nutrition.

China’s marriage squeeze: A decomposition into age and sex structure

PubMed Central

LI, Xiaomin; LI, Shuzhuo; FELDMAN, Marcus W.

2016-01-01

Most recent studies of marriage patterns in China have emphasized the male-biased sex ratio but have largely neglected age structure as a factor in China’s male marriage squeeze. In this paper we develop an index we call “spousal sex ratio” (SSR) to measure the marriage squeeze, and a method of decomposing the proportion of male surplus into age and sex structure effects within a small spousal age difference interval. We project that China’s marriage market will be confronted with a relatively severe male squeeze. For the decomposition of the cohort aged 30, from 2010 to 2020 age structure will be dominant, while from 2020 through 2034 the contribution of age structure will gradually decrease and that of sex structure will increase. From then on, sex structure will be dominant. The index and decomposition, concentrated on a specific female birth cohort, can distinguish spousal competition for single cohorts which may be covered by a summary index for the whole marriage market; these can also be used for consecutive cohorts to reflect the situation of the whole marriage market. PMID:27242390

Age and growth of the kiyi, Leucichthys kiyi Koelz, in Lake Michigan

USGS Publications Warehouse

Deason, Hilary J.; Hile, Ralph

1947-01-01

Ages were determined and individual growth histories were calculated from the examination and measurement of the scales of 1,649 kiyis captured at seven localities in Lake Michigan in 1931 and 1932. The numbers of individuals employed for the investigation of other phases of the life history (such as length-frequency distributions, length-weight relationship, and sex ratio) varied according to the amount of data available or required. Age-group IV was dominant in the 1931 collections from Racine, Port Washington, and Kewaunee, Wisconsin, and age-group V dominated the 1932 samples from the Fox Islands and from three localities southward of Manistique, Michigan. A trend was noticeable toward an increase in average age from south to north. Among the explanations suggested for the observed differences in age composition were: Variation with latitude in the natural span of life; differences in fishing intensity; fluctuations in the strength of year classes (to account possibly for the shift in the dominant age group from 1931 to 1932). The oldest male kiyi belonged to the VII group and the oldest female was a member of the X group. The possible distorting effects of such factors as gear selection traceable to differences in the mesh sizes of nets fished in 1931 and 1932, selection by nets on the basis of the condition (K) of the fish, and local variations in fishing intensity and hence in the selective destruction of rapidly growing individuals in the fishery were held to be sufficiently great to render doubtful the significance of most of the observed local differences in growth rate. Kiyis from all samples were combined to determine the general growth in length. The growth in weight of the Fox Islands fish, however, was considered separately as these fish were consistently lighter than kiyis of corresponding length from other localities. The Lake Michigan kiyi grows slowly, with the females growing slightly more rapidly than the males. The grand average calculated

Structure and growth of the mesoscopic surfactant/silica thin films

NASA Astrophysics Data System (ADS)

Zhou, Linbo

1999-10-01

We report the study of the structure and the growth of the mesoscopic surfactant/silica thin films. We use X-ray diffraction coupled with Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM), Transmission Electron Microscope (TEM) and light scattering techniques to study the structure, lattice strain and the drying effect of the thin films as well as the growth kinetics and mechanism. The surfactant/silica materials are synthesized using the supramolecular assemblies of the surfactant molecules to template the condensation of the inorganic species. The subsequent calcination yields the mesoporous silica materials, which have many application properties such as unusual electronic, optical, magnetic and elastic characteristics. The films are grown on mica, graphite and silicon substrates in an acidic CTAC (Cetyltrimethyl Ammonium Chloride)/TEOS (Tetraethyl Orthosilicate) solution and are found to consist of the hexagonally packed tubules. The substrate plays an important role in the epitaxial arrangement of the film. We use the light scattering and cryo TEM to study the micelle morphology and aggregation in the solution and use synchrotron radiation X-ray diffraction to study the growth of the film at the solid/liquid interfaces in-situ. An induction time is found followed by the growth of the film at a nonlinear growth rate. The induction time depends on the ratio of the concentrations of CTAC to TEOS in the high CTAC concentration regime. The growth kinetics and mechanism are elucidated in a context of a growth model. For the technological application, Micromolding in Capillaries (MIMIC) technique and the field guided growth are used to process the patterned mesoscopic surfactant/silica thin films and align the nanotubules into the desired orientation. X-ray diffraction characterization has been performed to study the structure and orientation of the thin films. The combined influence of the electric field and the confinement of the mold allows the

Age-related changes in brain structural covariance networks.

PubMed

Li, Xinwei; Pu, Fang; Fan, Yubo; Niu, Haijun; Li, Shuyu; Li, Deyu

2013-01-01

Previous neuroimaging studies have suggested that cerebral changes over normal aging are not simply characterized by regional alterations, but rather by the reorganization of cortical connectivity patterns. The investigation of structural covariance networks (SCNs) using voxel-based morphometry is an advanced approach to examining the pattern of covariance in gray matter (GM) volumes among different regions of the human cortex. To date, how the organization of critical SCNs change during normal aging remains largely unknown. In this study, we used an SCN mapping approach to investigate eight large-scale networks in 240 healthy participants aged 18-89 years. These participants were subdivided into young (18-23 years), middle aged (30-58 years), and older (61-89 years) subjects. Eight seed regions were chosen from widely reported functional intrinsic connectivity networks. The voxels showing significant positive associations with these seed regions were used to describe the topological organization of an SCN. All of these networks exhibited non-linear patterns in their spatial extent that were associated with normal aging. These networks, except the primary motor network, had a distributed topology in young participants, a sharply localized topology in middle aged participants, and were relatively stable in older participants. The structural covariance derived using the primary motor cortex was limited to the ipsilateral motor regions in the young and older participants, but included contralateral homologous regions in the middle aged participants. In addition, there were significant between-group differences in the structural networks associated with language-related speech and semantics processing, executive control, and the default-mode network (DMN). Taken together, the results of this study demonstrate age-related changes in the topological organization of SCNs, and provide insights into normal aging of the human brain.

Species richness, abundance, and composition of hypogeous and epigeous ectomycorrhizal fungal sporocarps in young, rotation-age, and old-growth stands of Douglas-fir (Pseudotsuga menziesii) in the Cascade Range of Oregon, U.S.A.

Treesearch

J.E. Smith; R. Molina; M.M.P. Huso; D.L. Luoma; D. McKay; M.A. Castellano; T. Lebel; Y. Valachovic

2002-01-01

Knowledge of the community structure of ectomycorrhizal fungi among successional forest age-classes is critical for conserving fungal species diversity. Hypogeous and epigeous sporocarps were collected from three replicate stands in each of three forest age-classes (young, rotation-age, and old-growth) of Douglas-fir (Pseudotsuga menziesii (Mirb.)...

Size and age structure of anadromous and landlocked populations of Rainbow Smelt

USGS Publications Warehouse

O'Malley, Andrew; Enterline, Claire; Zydlewski, Joseph D.

2017-01-01

Rainbow Smelt Osmerus mordax are widely distributed in both anadromous and landlocked populations throughout northeastern North America; abundance, size at age, and maximum size vary widely among populations and life histories. In the present study, size at age, von Bertalanffy growth parameters, population age distributions, and precision and bias in age assessment based on scales and sectioned otoliths were compared between ecotypes and among populations of Rainbow Smelt. To compare the ecotypes, we collected spawning adults from four anadromous and three landlocked populations in Maine during spring 2014. A significant bias was identified in only one of four scale comparisons but in four of seven otolith comparisons; however, a comparable level of precision was indicated. Anadromous populations had larger and more variable size at age and von Bertalanffy growth parameters than landlocked fish. Populations were composed of ages 1–4; six populations were dominated by age-2 or age-3 individuals, and one population was dominated by age-1 fish. These data suggest the presence of considerable plasticity among populations. A latitudinal gradient was observed in the anadromous Rainbow Smelt, which may show signs of population stress at the southern extent of their distribution.

Dry-growth of silver single-crystal nanowires from porous Ag structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chuantong, E-mail: chenchuantong@sanken.osaka-u.ac.jp; Nagao, Shijo; Jiu, Jinting

A fabrication method of single crystal Ag nanowires in large scale is introduced without any chemical synthesis in wet processes, which usually generates fivefold twinned nanowires of fcc metals. Dense single-crystal nanowires grow on a mechanically polished surface of micro-porous Ag structure, which is created from Ag micro-particles. The diameter and the length of the nanowires can be controlled simply by changing the temperature and the time of the heating during the nanowire growth in air. Unique growth mechanism is described in detail, based on stress-induced migration accelerated by the micro-porous structure where the origin of Ag nanowires growth ismore » incubated. Transmission electron microscopy analysis on the single crystal nanowires is also presented. This simple method offered an alternative preparation for metallic nanowires, especially with the single crystal structure in numerous applications.« less

An analytical model of stand dynamics as a function of tree growth, mortality and recruitment: the shade tolerance-stand structure hypothesis revisited.

PubMed

Zavala, Miguel A; Angulo, Oscar; Bravo de la Parra, Rafael; López-Marcos, Juan C

2007-02-07

Light competition and interspecific differences in shade tolerance are considered key determinants of forest stand structure and dynamics. Specifically two main stand diameter distribution types as a function of shade tolerance have been proposed based on empirical observations. All-aged stands of shade tolerant species tend to have steeply descending, monotonic diameter distributions (inverse J-shaped curves). Shade intolerant species in contrast typically exhibit normal (unimodal) tree diameter distributions due to high mortality rates of smaller suppressed trees. In this study we explore the generality of this hypothesis which implies a causal relationship between light competition or shade tolerance and stand structure. For this purpose we formulate a partial differential equation system of stand dynamics as a function of individual tree growth, recruitment and mortality which allows us to explore possible individual-based mechanisms--e.g. light competition-underlying observed patterns of stand structure--e.g. unimodal or inverse J-shaped equilibrium diameter curves. We find that contrary to expectations interspecific differences in growth patterns can result alone in any of the two diameter distributions types observed in the field. In particular, slow growing species can present unimodal equilibrium curves even in the absence of light competition. Moreover, light competition and shade intolerance evaluated both at the tree growth and mortality stages did not have a significant impact on stand structure that tended to converge systematically towards an inverse J-shaped curves for most tree growth scenarios. Realistic transient stand dynamics for even aged stands of shade intolerant species (unimodal curves) were only obtained when recruitment was completely suppressed, providing further evidence on the critical role played by juvenile stages of tree development (e.g. the sampling stage) on final forest structure and composition. The results also point out the

Longitudinal growth of head circumference in term symmetric and asymmetric small for gestational age infants.

PubMed

Kaur, Harvinder; Bhalla, A K; Kumar, Praveen

2012-07-01

To study longitudinal growth pattern of head circumference of full-term symmetric and asymmetric small for gestational age (SGA) infants of the two sexes during first year of life. Mixed-longitudinal growth research design. Head circumference amongst full-term 100 symmetric, 100 asymmetric as well as 100 appropriate for gestational age (AGA) infants was measured at birth, 1, 3, 6, 9 and 12 months of age using standardized technique and instrument. The mean head circumference of male symmetric SGA infants measured significantly (p≤0.001) smaller than asymmetric SGA infants while, in female symmetric SGA infants it measured shorter beyond 6 months. As compared to AGA infants, head circumference in symmetric and asymmetric SGA infants measured significantly smaller in size. Growth velocity for head circumference amongst symmetric and asymmetric SGA male infants did not show statistically significant differences. Rate of head circumference growth remained significantly higher amongst female asymmetric SGA infants than the symmetric ones between 3 and 6 months while, a reversal of trend was observed between 9 and 12 months. The better growth attainments for head circumference of male and female asymmetric SGA infants than their symmetric SGA counterparts during first postnatal year of life may be attributed to the continuation of influence of "head sparing" experienced by asymmetric SGA babies during prenatal life. Copyright © 2011 Elsevier Ltd. All rights reserved.

Separating the effects of intra- and interspecific age-structured interactions in an experimental fish assemblage

USGS Publications Warehouse

Taylor, R.C.; Trexler, J.C.; Loftus, W.F.

2001-01-01

We documented patterns of age-structured biotic interactions in four mesocosm experiments with an assemblage of three species of co-occurring fishes from the Florida Everglades, the eastern mosquitofish (Gambusia holbrooki), sailfin molly (Poecilia latipinna), and bluefin killifish (Lucania goodei). These species were chosen based on their high abundance and overlapping diets. Juvenile mosquitofish and sailfin mollies, at a range of densities matching field estimates, were maintained in the presence of adult mosquitofish, sailfin mollies, and bluefin killifish to test for effects of competition and predation on juvenile survival and growth. The mesocosms held 1,200 1 of water and all conditions were set to simulate those in Shark River Slough, Everglades National Park (ENP), USA. We placed floating mats of periphyton and bladderwort in each tank in standard volumes that matched field values to provide cover and to introduce invertebrate prey. Of 15 possible intra- and interspecific age-structured interactions, we found 7 to be present at the densities of these fish found in Shark River Slough marshes. Predation by adult mosquitofish on juvenile fish, including conspecifics, was the strongest effect observed. We also observed growth limitation in mosquitofish and sailfin molly juveniles from intra- and interspecific competition. When maintained at high densities, juvenile mosquitofish changed their diets to include more cladocerans and fewer chironomid larvae relative to low densities. We estimated size-specific gape limitation by adult mosquitofish when consuming juvenile mosquitofish and sailfin mollies. At high field densities, intraspecific competition might prolong the time period when juveniles are vulnerable to predation by adult mosquitofish. These results suggest that path analysis, or other techniques used to document food-web interactions, must include age-specific roles of these fishes.

Grain Growth and Precipitation Behavior of Iridium Alloy DOP-26 During Long Term Aging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, Dean T.; Muralidharan, Govindarajan; Fox, Ethan E.

The influence of long term aging on grain growth and precipitate sizes and spatial distribution in iridium alloy DOP-26 was studied. Samples of DOP-26 were fabricated using the new process, recrystallized for 1 hour (h) at 1375 C, then aged at either 1300, 1400, or 1500 C for times ranging from 50 to 10,000 h. Grain size measurements (vertical and horizontal mean linear intercept and horizontal and vertical projection) and analyses of iridium-thorium precipitates (size and spacing) were made on the longitudinal, transverse, and rolling surfaces of the as-recrystallized and aged specimens from which the two-dimensional spatial distribution and meanmore » sizes of the precipitates were obtained. The results obtained from this study are intended to provide input to grain growth models.« less

Age and growth of round gobies in Lake Huron: Implications for food web dynamics

USGS Publications Warehouse

Duan, You J.; Madenjian, Charles P.; Xie, Cong X.; Diana, James S.; O'Brien, Timothy P.; Zhao, Ying M.; He, Ji X.; Farha, Steve A.; Huo, Bin

2016-01-01

Although the round goby (Neogobius melanostomus) has become established throughout the Laurentian Great Lakes, information is scarce on spatial variation in round goby growth between and within lakes. Based on a sample of 754 specimens captured in 2014, age, growth, and mortality of round gobies at four locations in Lake Huron were assessed via otolith analysis. Total length (TL) of round gobies ranged from 44 to 111 mm for Saginaw Bay, from 45 to 115 mm for Rockport, from 50 to 123 mm for Hammond Bay, and from 51 to 118 mm for Thunder Bay. Estimated ages of round gobies ranged from 2 to 5 years for Saginaw Bay, from 2 to 6 years for Rockport, and from 2 to 7 years for Hammond Bay and Thunder Bay. Sex-specific, body–otolith relationships were used to back-calculate total lengths at age, which were then fitted to von Bertalanffy growth models. For each sex, round goby growth showed significant spatial variation among the four locations within Lake Huron. At all four locations in Lake Huron, males grew significantly faster than females and attained a larger asymptotic length than females. Annual mortality rate estimates were high (62 to 85%), based on catch-curve analysis, suggesting that round gobies may be under predatory control in Lake Huron.

Radiocarbon-based ages and growth rates of bamboo corals from the Gulf of Alaska

NASA Astrophysics Data System (ADS)

Roark, E. Brendan; Guilderson, Thomas P.; Flood-Page, Sarah; Dunbar, Robert B.; Ingram, B. Lynn; Fallon, Stewart J.; McCulloch, Malcolm

2005-02-01

Deep-sea coral communities have long been recognized by fisherman as areas that support large populations of commercial fish. As a consequence, many deep-sea coral communities are threatened by bottom trawling. Successful management and conservation of this widespread deep-sea habitat requires knowledge of the age and growth rates of deep-sea corals. These organisms also contain important archives of intermediate and deep-water variability, and are thus of interest in the context of decadal to century-scale climate dynamics. Here, we present Δ14C data that suggest that bamboo corals from the Gulf of Alaska are long-lived (75-126 years) and that they acquire skeletal carbon from two distinct sources. Independent verification of our growth rate estimates and coral ages is obtained by counting seasonal Sr/Ca cycles and probable lunar cycle growth bands.

[Effects of crop tree release on stand growth and stand structure of Cunninghamia lanceolata plantation].

PubMed

Wu, Jian-qiang; Wang, Yi-xiang; Yang, Yi; Zhu, Ting-ting; Zhu, Xu-dan

2015-02-01

Crop trees were selected in a 26-year-old even-aged Cunninghamia lanceolata plantation in Lin' an, and compared in plots that were released and unreleased to examine growth and structure responses for 3 years after thinning. Crop tree release significantly increased the mean increments of diameter and volume of individual tree by 1.30 and 1.25 times relative to trees in control stands, respectively. The increments of diameter and volume of crop trees were significantly higher than those of general trees in thinning plots, crop trees and general trees in control plots, which suggested that the responses from different tree types to crop tree release treatment were different. Crop tree release increased the average distances of crop trees to the nearest neighboring trees, reducing competition among crop trees by about 68.2%. 3-year stand volume increment for thinning stands had no significant difference with that of control stands although the number of trees was only 81.5% of the control. Crop trees in thinned plots with diameters over than 14 cm reached 18.0% over 3 years, compared with 12.0% for trees without thinning, suggesting that crop tree release benefited the larger individual trees. The pattern of tree locations in thinning plots tended to be random, complying with the rule that tree distribution pattern changes with growth. Crop tree release in C. lanceolata plantation not only promoted the stand growth, but also optimized the stand structure, benefiting crop trees sustained rapid growth and larger diameter trees production.

Effect of crown growing space and age on the growth of northern red oak

Treesearch

Gary W. Miller

1997-01-01

Cultural practices can be applied in even-age stands to reallocate site resources to selected crop trees. Precornrnercial thinning in sapling stands can increase diameter growth and improve species composition of trees in the main canopy. Commercial thinning in sawtimber stands also increases diameter growth of crop trees, improves residual stand quality, and removes...

Development of Growth Charts of Pakistani Children Aged 4-15 Years Using Quantile Regression: A Cross-sectional Study

PubMed Central

Khan, Nazeer; Siddiqui, Junaid S; Baig-Ansari, Naila

2018-01-01

Background Growth charts are essential tools used by pediatricians as well as public health researchers in assessing and monitoring the well-being of pediatric populations. Development of these growth charts, especially for children above five years of age, is challenging and requires current anthropometric data and advanced statistical analysis. These growth charts are generally presented as a series of smooth centile curves. A number of modeling approaches are available for generating growth charts and applying these on national datasets is important for generating country-specific reference growth charts. Objective To demonstrate that quantile regression (QR) as a viable statistical approach to construct growth reference charts and to assess the applicability of the World Health Organization (WHO) 2007 growth standards to a large Pakistani population of school-going children. Methodology This is a secondary data analysis using anthropometric data of 9,515 students from a Pakistani survey conducted between 2007 and 2014 in four cities of Pakistan. Growth reference charts were created using QR as well as the LMS (Box-Cox transformation (L), the median (M), and the generalized coefficient of variation (S)) method and then compared with WHO 2007 growth standards. Results Centile values estimated by the LMS method and QR procedure had few differences. The centile values attained from QR procedure of BMI-for-age, weight-for-age, and height-for-age of Pakistani children were lower than the standard WHO 2007 centile. Conclusion QR should be considered as an alternative method to develop growth charts for its simplicity and lack of necessity to transform data. WHO 2007 standards are not suitable for Pakistani children. PMID:29632748

Development of Growth Charts of Pakistani Children Aged 4-15 Years Using Quantile Regression: A Cross-sectional Study.

PubMed

Iftikhar, Sundus; Khan, Nazeer; Siddiqui, Junaid S; Baig-Ansari, Naila

2018-02-02

Background Growth charts are essential tools used by pediatricians as well as public health researchers in assessing and monitoring the well-being of pediatric populations. Development of these growth charts, especially for children above five years of age, is challenging and requires current anthropometric data and advanced statistical analysis. These growth charts are generally presented as a series of smooth centile curves. A number of modeling approaches are available for generating growth charts and applying these on national datasets is important for generating country-specific reference growth charts. Objective To demonstrate that quantile regression (QR) as a viable statistical approach to construct growth reference charts and to assess the applicability of the World Health Organization (WHO) 2007 growth standards to a large Pakistani population of school-going children. Methodology This is a secondary data analysis using anthropometric data of 9,515 students from a Pakistani survey conducted between 2007 and 2014 in four cities of Pakistan. Growth reference charts were created using QR as well as the LMS (Box-Cox transformation (L), the median (M), and the generalized coefficient of variation (S)) method and then compared with WHO 2007 growth standards. Results Centile values estimated by the LMS method and QR procedure had few differences. The centile values attained from QR procedure of BMI-for-age, weight-for-age, and height-for-age of Pakistani children were lower than the standard WHO 2007 centile. Conclusion QR should be considered as an alternative method to develop growth charts for its simplicity and lack of necessity to transform data. WHO 2007 standards are not suitable for Pakistani children.

Two Growth Modes of Graphitic Carbon Nanofibers with Herring-Bone Structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merkulov, Igor A; Melechko, Anatoli Vasilievich; Wells, Jack C

2005-01-01

A simple mathematical model of the carbon nanofiber catalytic growth process is presented. Two major types of the fiber-catalyst interface shapes have been identified and described having qualitatively different structure in the center of a nanofiber. Presently, we discuss that the appearance of the irregular structure in the nanofiber central area is a result of curved-interface-growth kinematics. We suggest the method to determine the phenomenological parameters of the developed model from experimental data.

Two growth modes of graphitic carbon nanofibers with herring-bone structure

NASA Astrophysics Data System (ADS)

Merkulov, I. A.; Meleshko, A. V.; Wells, J. C.; Cui, H.; Merkulov, V. I.; Simpson, M. L.; Lowndes, D. H.

2005-07-01

A simple mathematical model of the carbon nanofiber catalytic growth process is presented. Two major types of the fiber-catalyst interface shapes have been identified and described having qualitatively different structure in the center of a nanofiber. Presently, we discuss that the appearance of the irregular structure in the nanofiber central area is a result of curved-interface-growth kinematics. We suggest the method to determine the phenomenological parameters of the developed model from experimental data.

The growth status of North Korean refugee children and adolescents from 6 to 19 years of age.

PubMed

Pak, Sunyoung

2010-12-01

This paper is a study of the growth status of 1406 North Korean refugee children and adolescents who were between 6 and 19.9 years of age at the time of their arrival in South Korea, during the years 1995-2007, as compared with that of their South Korean peers. Refugee children of 6.5 years of age were found to be taller and heavier than North Korean children of the same age residing in North Korea. On the other hand, all of the North Korean refugee boys and girls were shorter and weighed less than their South Korean peers. This disparity in height and weight growth status was smallest during the pre-teen years and then began to increase, peaking in the mid-teen years and decreasing in the late-teen years, with the late-teen disparity being still larger than the pre-teen one. This pattern of disparity suggests that the greatest gap observed in mid-teen years was caused by differences in growth tempos during the period of pubertal growth and that the final differences in body size between the North and South Korean adults were partly pubertal in origin. The mean height-for-age z-score (HAZ) and weight-for-age z-score (WAZ) of the North Korean refugee boys were significantly lower than those of the North Korean refugee girls, indicating that the girls' growth status was better than that of the boys. In addition, the WAZ of the North Korean refugee children and adolescents was higher than their HAZ, indicating that their growth in height is poorer than that of weight. A regression analysis revealed that the mean HAZ of North Korean refugee children and adolescents born between 1995 and 1999, a period during which North Korea suffered a famine, was not statistically significantly lower than that of those born earlier. The time that the North Korean children and adolescents spent outside of North Korea before entering South Korea was discovered to have had a positive effect on their growth status, suggesting that they experienced some degree of catch-up growth while

Developing pongid dentition and its use for ageing individual crania in comparative cross-sectional growth studies.

PubMed

Dean, M C; Wood, B A

1981-01-01

This study of the developing pongid dentition is based on cross-sectional radiographic data of juvenile Pan troglodytes, Gorilla gorilla, and Pongo pygmaeus skulls. Comparisons with developmental features of the human dentition are made, and possible explanations for the formation of larger teeth within the reduced pongid growth period are discussed. The data presented in this study provide an alternative method for ageing individual pongid crania in comparative cross-sectional growth studies. The advantages of this method are demonstrated by ageing individual Gorilla crania form radiographs and plotting relative dental age against length of the jaw.

Growth of InAs/InP core-shell nanowires with various pure crystal structures.

PubMed

Gorji Ghalamestani, Sepideh; Heurlin, Magnus; Wernersson, Lars-Erik; Lehmann, Sebastian; Dick, Kimberly A

2012-07-20

We have studied the epitaxial growth of an InP shell on various pure InAs core nanowire crystal structures by metal-organic vapor phase epitaxy. The InP shell is grown on wurtzite (WZ), zinc-blende (ZB), and {111}- and {110}-type faceted ZB twin-plane superlattice (TSL) structures by tuning the InP shell growth parameters and controlling the shell thickness. The growth results, particularly on the WZ nanowires, show that homogeneous InP shell growth is promoted at relatively high temperatures (∼500 °C), but that the InAs nanowires decompose under the applied conditions. In order to protect the InAs core nanowires from decomposition, a short protective InP segment is first grown axially at lower temperatures (420-460 °C), before commencing the radial growth at a higher temperature. Further studies revealed that the InP radial growth rate is significantly higher on the ZB and TSL nanowires compared to WZ counterparts, and shows a strong anisotropy in polar directions. As a result, thin shells were obtained during low temperature InP growth on ZB structures, while a higher temperature was used to obtain uniform thick shells. In addition, a schematic growth model is suggested to explain the basic processes occurring during the shell growth on the TSL crystal structures.

Deep grey matter growth predicts neurodevelopmental outcomes in very preterm children.

PubMed

Young, Julia M; Powell, Tamara L; Morgan, Benjamin R; Card, Dallas; Lee, Wayne; Smith, Mary Lou; Sled, John G; Taylor, Margot J

2015-05-01

We evaluated whether the volume and growth rate of critical brain structures measured by MRI in the first weeks of life following very preterm (<32/40 weeks) birth could predict subsequent neurodevelopmental outcomes at 4 years of age. A significant proportion of children born very prematurely have cognitive deficits, but these problems are often only detected at early school age. Structural T2-weighted magnetic resonance images were acquired in 96 very preterm neonates scanned within 2 weeks of birth and 70 of these at term-equivalent age. An automated 3D image analysis procedure was used to measure the volume of selected brain structures across all scans and time points. At 4 years of age, 53 children returned for neuropsychological assessments evaluating IQ, language and visual motor integration. Associations with maternal education and perinatal measures were also explored. Multiple regression analyses revealed that growth of the caudate and globus pallidus between preterm birth and term-equivalent age predicted visual motor integration scores after controlling for sex and gestational age. Further associations were found between caudate and putamen growth with IQ and language scores. Analyses at either preterm or term-equivalent age only found associations between normalized deep grey matter growth and visual motor integration scores at term-equivalent age. Maternal education levels were associated with measures of IQ and language, but not visual motor integration. Thalamic growth was additionally linked with perinatal measures and presence of white matter lesions. These results highlight deep grey matter growth rates as promising biomarkers of long-term outcomes following very preterm birth, and contribute to our understanding of the brain-behaviour relations in these children. Copyright © 2015 Elsevier Inc. All rights reserved.

Making the Right Moves: Promoting Smart Growth and Active Aging in Communities

EPA Science Inventory

This article describes an award program sponsored by the U.S. Environmental Protection Agency for excellence in smart growth and active aging. Having examined qualitative and quantitative data, we suggest that any community can foster changes to improve the health and well-being ...

National Growth Charts for United Arab Emirates Children With Down Syndrome From Birth to 15 Years of Age

PubMed Central

H Aburawi, Elhadi; Nagelkerke, Nicolas; Deeb, Asma; Abdulla, Shahrban; Abdulrazzaq, Yousef M.

2015-01-01

Background Specific centile growth charts for children with Down syndrome (DS) have been produced in many countries and are known to differ from those of normal children. Since growth assessment depends on the growth pattern characteristic for these conditions, disorder-specific charts are desirable for various ethnic groups. Aims To provide cross-sectional weight, height, and head circumference (HC) references for healthy United Arab Emirates (UAE) children with DS. Methods A retrospective and cross-sectional growth study of Emirati children with DS, aged 0 to 18 years old, was conducted. Height, weight, and HC were measured in each child. Cole’s LMS statistical method was applied to estimate age-specific percentiles, and measurements were compared to UAE reference values for normal children. Results Incidence of DS in the UAE population is 1 in 374 live births (267 in 10 000 live births). We analyzed 1263 growth examinations of 182 children with DS born between 1994 and 2012. The male-to-female ratio was 1.6:1. Height, weight, and HC centile charts were constructed for ages 0 to 13 years. The prevalence of overweight and obesity in DS children aged 10 to 13 years of age was 32% and 19%, respectively. The DS children were significantly shorter and heavier than normal children in the UAE. Conclusions Weight, height, and HC growth charts were created for children with DS. These can be used as a reference standard for the UAE children with DS. Overweight and obesity are quite common in DS children ≥10 years of age, as DS children tend to be shorter and heavier than non-DS children. PMID:25196167

Radiocarbon-Based Ages and Growth Rates of Bamboo Corals from the Gulf of Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roark, E B; Guilderson, T P; Flood-Page, S

2004-12-12

Deep-sea coral communities have long been recognized by fisherman as areas that support large populations of commercial fish. As a consequence, many deep-sea coral communities are threatened by bottom trawling. Successful management and conservation of this widespread deep-sea habitat requires knowledge of the age and growth rates of deep-sea corals. These organisms also contain important archives of intermediate and deep-water variability, and are thus of interest in the context of decadal to century-scale climate dynamics. Here, we present {Delta}{sup 14}C data that suggest that bamboo corals from the Gulf of Alaska are long-lived (75-126 years) and that they acquire skeletalmore » carbon from two distinct sources. Independent verification of our growth rate estimates and coral ages is obtained by counting seasonal Sr/Ca cycles and probable lunar cycle growth bands.« less

Mind-Reading Ability and Structural Connectivity Changes in Aging.

PubMed

Cabinio, Monia; Rossetto, Federica; Blasi, Valeria; Savazzi, Federica; Castelli, Ilaria; Massaro, Davide; Valle, Annalisa; Nemni, Raffaello; Clerici, Mario; Marchetti, Antonella; Baglio, Francesca

2015-01-01

The Mind-Reading ability through the eyes is an important component of the affective Theory of Mind (ToM), which allows people to infer the other's mental state from the eye gaze. The aim of the present study was to investigate to which extent age-associated structural brain changes impact this ability and to determine if this association is related to executive functions in elderly subjects. For this purpose, Magnetic Resonance Imaging was used to determine both gray matter and white matter (WM) areas associated with aging. The resulting areas have been included in a subsequent correlation analysis to detect the brain regions whose structure was associated with the Mind-Reading ability through the eyes, assessed with the Italian version of the "Reading the Mind in the Eyes" (RME) test, in a sample of 36 healthy subjects ranging from 24 to 79 years of age. The analysis resulted in three important findings: (1) the performance to the RME test is relatively stable across the decades 20-70 (despite a slight decrease of this ability with aging) and independent from executive functions; (2) structural brain imaging demonstrated the involvement of a great number of cortical ToM areas for the execution of the RME test: the bilateral precentral gyrus, the bilateral posterior insula, the left superior temporal gyrus and the left inferior frontal gyrus, which also showed a significant volume decrease with age; (3) an age and task-related decline in WM connectivity on left fronto-temporal portion of the brain. Our results confirm the age-related structural modifications of the brain and show that these changes have an influence on the Mind-Reading ability through the eyes.

Retrograde degeneration of neurite membrane structural integrity of nerve growth cones following in vitro exposure to mercury.

PubMed

Leong, C C; Syed, N I; Lorscheider, F L

2001-03-26

Inhalation of mercury vapor (Hg0) inhibits binding of GTP to rat brain tubulin, thereby inhibiting tubulin polymerization into microtubules. A similar molecular lesion has also been observed in 80% of brains from patients with Alzheimer disease (AD) compared to age-matched controls. However the precise site and mode of action of Hg ions remain illusive. Therefore, the present study examined whether Hg ions could affect membrane dynamics of neurite growth cone morphology and behavior. Since tubulin is a highly conserved cytoskeletal protein in both vertebrates and invertebrates, we hypothesized that growth cones from animal species could be highly susceptible to Hg ions. To test this possibility, the identified, large Pedal A (PeA) neurons from the central ring ganglia of the snail Lymnoea stagnalis were cultured for 48 h in 2 ml brain conditioned medium (CM). Following neurite outgrowth, metal chloride solution (2 microl) of Hg, Al, Pb, Cd, or Mn (10(-7) M) was pressure applied directly onto individual growth cones. Time-lapse images with inverted microscopy were acquired prior to, during, and after the metal ion exposure. We demonstrate that Hg ions markedly disrupted membrane structure and linear growth rates of imaged neurites in 77% of all nerve growth cones. When growth cones were stained with antibodies specific for both tubulin and actin, it was the tubulin/microtubule structure that disintegrated following Hg exposure. Moreover, some denuded neurites were also observed to form neurofibrillary aggregates. In contrast, growth cone exposure to other metal ions did not effect growth cone morphology, nor was their motility rate compromised. To determine the growth suppressive effects of Hg ions on neuronal sprouting, cells were cultured either in the presence or absence of Hg ions. We found that in the presence of Hg ions, neuronal somata failed to sprout, whereas other metalic ions did not effect growth patterns of cultured PeA cells. We conclude that this

Kinetic theory of age-structured stochastic birth-death processes

NASA Astrophysics Data System (ADS)

Greenman, Chris D.; Chou, Tom

2016-01-01

Classical age-structured mass-action models such as the McKendrick-von Foerster equation have been extensively studied but are unable to describe stochastic fluctuations or population-size-dependent birth and death rates. Stochastic theories that treat semi-Markov age-dependent processes using, e.g., the Bellman-Harris equation do not resolve a population's age structure and are unable to quantify population-size dependencies. Conversely, current theories that include size-dependent population dynamics (e.g., mathematical models that include carrying capacity such as the logistic equation) cannot be easily extended to take into account age-dependent birth and death rates. In this paper, we present a systematic derivation of a new, fully stochastic kinetic theory for interacting age-structured populations. By defining multiparticle probability density functions, we derive a hierarchy of kinetic equations for the stochastic evolution of an aging population undergoing birth and death. We show that the fully stochastic age-dependent birth-death process precludes factorization of the corresponding probability densities, which then must be solved by using a Bogoliubov--Born--Green--Kirkwood--Yvon-like hierarchy. Explicit solutions are derived in three limits: no birth, no death, and steady state. These are then compared with their corresponding mean-field results. Our results generalize both deterministic models and existing master equation approaches by providing an intuitive and efficient way to simultaneously model age- and population-dependent stochastic dynamics applicable to the study of demography, stem cell dynamics, and disease evolution.

Shame, hope, intimacy and growth: Dementia distress and growth in families from the perspective of senior aged care professionals.

PubMed

Walmsley, Bruce; McCormack, Lynne

2016-11-01

Minimal research explores the impact of dementia and a dementia diagnosis on families from the unique vantage of senior health professionals. The participants of this study, eight senior aged care professionals, provided unique interpretative insights into family dynamics and sense-making on the journey with dementia, and their own role in that journey. Both positive and negative perspectives were sought. Data from semi-structured interviews were analysed using Interpretative Phenomenological Analysis (IPA). One superordinate theme, Dementia naiveté; redefined intimacy, overarched Embarrassed shame; Maintaining hope; Redefining a model of intimacy; and Redefined relational intimacy and growth Within these themes, the participants shed light on hurtful embarrassment and shame experienced by families associated with the diagnostic label given to a loved one. This label was perceived to either trigger separation, hurt and immobility through ignorance, or precipitate a frenzy of naive yet hopeful energy for seeking that elusive cure. The participants saw their role as one of enacting a new way of connecting what was with what could be. Thus, they modelled advocacy, integral care and relational intimacy. Validation came in witnessing a redefining of intimacy in many families who were able to embrace that holistic and empathic approach to the shifting presentation of dementia. Psychological well-being was observed to occur when families embraced growthful domains, e.g. acceptance, hope, relational closeness and altruistic concern for other families. Implications for future care models are discussed. © The Author(s) 2015.

The effect of growth rate and ageing on colour variation of European pond turtles.

PubMed

Ibáñez, Alejandro; Martín, José; Marzal, Alfonso; Bertolero, Albert

2017-06-01

Many chelonians have colourful dots, patches and stripes throughout their body that are made up, at least in part, of carotenoids. Therefore, turtles are very suitable models to study the evolution and functionality of carotenoid-based colouration. Recent studies suggested a close link between colouration and immune system in these taxa. However, more research is needed to understand the role of these colourful stripes and patches in turtle visual signalling. The purpose of this study was to explore the relationship between growth rate and colouration in European pond turtles. In particular, we wanted to answer the question of whether there is a trade-off between growth and colour expression. We also aimed to explore the effect of body size and age on colour variation. Turtles from a reintroduction-breeding program were recaptured, weighed and measured over an 8-year period to estimate their growth rates and age. We also measured with a spectrometer the reflectance of colour patches in two different body parts: shell and forelimb. We found that turtles with a faster growth rate had brighter limb stripes independently of their age. On the other hand, shell colouration was related to body size with larger turtles having brighter shell stripes and higher values of carotenoid chroma. Our results suggest that fast-growers may afford to express intense colourful limb stripes likely due to their higher intake of carotenoids that would modulate both growth and colour expression. However, shell colouration was related to body size probably due to ontogenetic differences in the diet, as juveniles are strictly carnivorous while adults are omnivorous. Alternatively, shell colouration might be involved in crypsis as the shell is visually exposed to predators.

The effect of growth rate and ageing on colour variation of European pond turtles

NASA Astrophysics Data System (ADS)

Ibáñez, Alejandro; Martín, José; Marzal, Alfonso; Bertolero, Albert

2017-06-01

Many chelonians have colourful dots, patches and stripes throughout their body that are made up, at least in part, of carotenoids. Therefore, turtles are very suitable models to study the evolution and functionality of carotenoid-based colouration. Recent studies suggested a close link between colouration and immune system in these taxa. However, more research is needed to understand the role of these colourful stripes and patches in turtle visual signalling. The purpose of this study was to explore the relationship between growth rate and colouration in European pond turtles. In particular, we wanted to answer the question of whether there is a trade-off between growth and colour expression. We also aimed to explore the effect of body size and age on colour variation. Turtles from a reintroduction-breeding program were recaptured, weighed and measured over an 8-year period to estimate their growth rates and age. We also measured with a spectrometer the reflectance of colour patches in two different body parts: shell and forelimb. We found that turtles with a faster growth rate had brighter limb stripes independently of their age. On the other hand, shell colouration was related to body size with larger turtles having brighter shell stripes and higher values of carotenoid chroma. Our results suggest that fast-growers may afford to express intense colourful limb stripes likely due to their higher intake of carotenoids that would modulate both growth and colour expression. However, shell colouration was related to body size probably due to ontogenetic differences in the diet, as juveniles are strictly carnivorous while adults are omnivorous. Alternatively, shell colouration might be involved in crypsis as the shell is visually exposed to predators.

Conversion of Successionally Stable Even-Aged Oak Stands to an Uneven-Aged Structure

Treesearch

Edward F. Loewenstein; James M. Guldin

2004-01-01

Developing a silvicultural prescription to convert an even-aged or unmanaged oak stand to an uneven-aged structure depends in large part on the length of time the existing overstory will live. Four conversion prescriptions, representing three initial stand conditions, are presented. Each prescription partitions the cut of the original overstory differently in time and...

Catch-Up Growth and Neurobehavioral Development among Full-Term, Small-for-Gestational-Age Children: A Nationwide Japanese Population-Based Study.

PubMed

Takeuchi, Akihito; Yorifuji, Takashi; Nakamura, Kazue; Tamai, Kei; Mori, Shigehiro; Nakamura, Makoto; Kageyama, Misao; Kubo, Toshihide; Ogino, Tatsuya; Kobayashi, Katsuhiro; Doi, Hiroyuki

2018-01-01

To examine the relationship between catch-up growth of full-term, small for gestational age (SGA) children and their neurobehavioral development. Data were obtained from a population-based nationwide Japanese longitudinal survey that started in 2001. Study participants were full-term children with information on height at 2 years of age (n = 32 533). Catch-up growth for SGA infants was defined as achieving a height at 2 years of age of more than -2.0 standard deviations for chronological age. Logistic regression analyses were used to estimate ORs and 95% CIs for the associations of SGA and catch-up growth status with neurobehavioral development at 2.5 and 8 years of age, adjusting for potential infant- and parent-related confounding factors. Fifteen percent of term SGA infants failed to catch up in height. At 2.5 years of age, SGA children without catch-up growth were more likely to be unable to climb stairs (OR, 10.42; 95% CI, 5.55-19.56) and unable to compose a 2-word sentence (OR, 3.58; 95% CI, 1.81-7.08) compared with children with normal growth at birth. Furthermore, SGA children without catch-up growth were at increased risk for aggressive behaviors (OR, 3.85; 95% CI, 1.19-12.47) at 8 years of age. Continuous follow-up for full-term SGA infants with failure of catch-up growth or poor postnatal growth may be beneficial for early detection and intervention for behavioral problems. Copyright © 2017 Elsevier Inc. All rights reserved.

Age structure changes and extraordinary lifespan in wild medfly populations.

PubMed

Carey, James R; Papadopoulos, Nikos T; Müller, Hans-Georg; Katsoyannos, Byron I; Kouloussis, Nikos A; Wang, Jane-Ling; Wachter, Kenneth; Yu, Wei; Liedo, Pablo

2008-06-01

The main purpose of this study was to test the hypotheses that major changes in age structure occur in wild populations of the Mediterranean fruit fly (medfly) and that a substantial fraction of individuals survive to middle age and beyond (> 3-4 weeks). We thus brought reference life tables and deconvolution models to bear on medfly mortality data gathered from a 3-year study of field-captured individuals that were monitored in the laboratory. The average time-to-death of captured females differed between sampling dates by 23.9, 22.7, and 37.0 days in the 2003, 2004, and 2005 field seasons, respectively. These shifts in average times-to-death provided evidence of changes in population age structure. Estimates indicated that middle-aged medflies (> 30 days) were common in the population. A surprise in the study was the extraordinary longevity observed in field-captured medflies. For example, 19 captured females but no reference females survived in the laboratory for 140 days or more, and 6 captured but no reference males survived in the laboratory for 170 days or more. This paper advances the study of aging in the wild by introducing a new method for estimating age structure in insect populations, demonstrating that major changes in age structure occur in field populations of insects, showing that middle-aged individuals are common in the wild, and revealing the extraordinary lifespans of wild-caught individuals due to their early life experience in the field.

The relationship of plasma urea nitrogen with growth traits and age at first estrus in gilts

USDA-ARS?s Scientific Manuscript database

Gilts that reach puberty at an earlier age with more backfat have greater lifetime productivity. Increased growth rates generally promote earlier age at first estrus; however, an association of age at first estrus with discrete measures of body fatness remains controversial. We tested the hypothesis...

Diameter Growth in Even- and Uneven-Aged Northern Hardwoods in New Hampshire Under Partial Cutting

Treesearch

William B. Leak

2004-01-01

One important concern in the conversion of even-aged stands to an uneven aged condition through individual-tree or small-group cutting is the growth response throughout the diameter-class distribution, especially of the understoty trees Increment-core sampling of an older, uneven-aged northern hardwood stand in New Hampshire under management for about 50 years...

The Oportunidades program increases the linear growth of children enrolled at young ages in urban Mexico.

PubMed

Leroy, Jef L; García-Guerra, Armando; García, Raquel; Dominguez, Clara; Rivera, Juan; Neufeld, Lynnette M

2008-04-01

The goal of this study was to evaluate the impact of Mexico's conditional cash transfer program, Oportunidades, on the growth of children <24 mo of age living in urban areas. Beneficiary families received cash transfers, a fortified food (targeted to pregnant and lactating women, children 6-23 mo, and children with low weight 2-4 y), and curative health services, among other benefits. Program benefits were conditional on preventative health care utilization and attendance of health and nutrition education sessions. We estimated the impact of the program after 2 y of operation in a panel of 432 children <24 mo of age at baseline (2002). We used difference-in-difference propensity score matching, which takes into account nonrandom program participation and the effects of unobserved fixed characteristics on outcomes. All models controlled for child age, sex, baseline anthropometry, and maternal height. Anthropometric Z-scores were calculated using the new WHO growth reference standards. There was no overall association between program participation and growth in children 6 to 24 mo of age. Children in intervention families younger than 6 mo of age at baseline grew 1.5 cm (P < 0.05) more than children in comparison families, corresponding to 0.41 height-for-age Z-scores (HAZ) (P < 0.05). They also gained an additional 0.76 kg (P < 0.01) or 0.47 weight-for-height Z-scores (P < 0.05). Children living in the poorest intervention households tended (0.05 < P < 0.10) to be taller than comparison children (0.9 cm, 0.27 HAZ). Oportunidades, with its strong nutrition component, is an effective tool to improve the growth of infants in poor urban households.

Exploring posttraumatic growth in Tamil children affected by the Indian Ocean Tsunami in 2004.

PubMed

Exenberger, Silvia; Ramalingam, Panch; Höfer, Stefan

2016-10-13

Few studies explore posttraumatic growth (PTG) in children from Eastern cultures. To help address this gap, the present study examined PTG among 177 South Indian children aged 8-17 years who were affected by the 2004 Tsunami. The study identifies the underlying factor structure of the Tamil version of the Revised Posttraumatic Growth Inventory for Children (PTGI-C-R), and aims to explore the prevalence of PTG, the relationship between distress and growth, and gender and age differences in PTG. The results of the principal component analysis indicated a two-factor structure with an interpersonal and a person-centred dimension of growth. The total scores of the Tamil PTGI-C-R were positively associated with posttraumatic stress symptoms (PTSS) and age. Moreover, there was a significant relationship between age and the person-centred growth subscale. Non-parametric tests found no gender differences in perceived growth. The role of socio-cultural factors on the nature of PTG is discussed. © 2016 International Union of Psychological Science.

Catch-up growth assessment in long-term physically neglected and emotionally abused preschool age male children.

PubMed

Oliván, Gonzalo

2003-01-01

To assess the catch-up growth of long-term physically neglected and emotionally abused preschool male children who have entered foster residential care and remained 1 year after initial placement. Longitudinal study over a 7-year period (1994-2001). So that a child was eligible for the study, three selection criteria were included: (1) aged between 24 and 48 months at the time of entry into residential facility, (2) having suffered both long-term (more than 6 months) physically neglected and emotionally abused, and (3) having stayed in foster care for 1 year after initial placement. Weight, height, and head circumference were established upon entry and re-assessed 1 year after initial placement, calculating the annual growth velocity. Results were compared with normal regional longitudinal standards of reference (Z score). Student's t test was used to assess statistically significant differences. During the study period, 87 children aged between 24 and 48 months (54 male/33 female) were admitted to residential facility after having suffered both long-term physical neglect and emotional abuse. Nevertheless, only 20 children (23% of the total admissions) met the third selection criteria (having remained 1 year after initial placement). Of these children, all were males and at placement they were between the ages of 30 and 42 months, with an average age of 36 months (1.9 SD). At placement, the analyzed parameters were below the normal standards, showing a statistically significant difference for height (Z score = -1.29; p = .008) and weight (Z score = -.75; p = .038). The annual growth velocity for all parameters was above the normal standards showing a statistically significant difference for height (Z score = +1.43; p = .009). One year after initial placement, the significant differences for height (Z score = -.68; p = .102) and weight (Z score = -.31; p = .435) with respect to the normal standards disappeared, though still remained below, showing a significant

Influence of beaver activity on summer growth and condition of age-2 Atlantic salmon parr

USGS Publications Warehouse

Sigourney, Douglas B.; Letcher, B.H.; Cunjak, R.A.

2006-01-01

The activity of beavers Castor canadensis in freshwater environments can have considerable localized impacts on the physical and biological components of riparian ecosystems. By changing the habitat of a stream, beaver dams can cause spatial variation in growth opportunity that may have direct consequences for the growth of resident fish. In a small stream in eastern Canada, we studied the effects of an ephemeral beaver pond on the growth and maturity of age-2 Atlantic salmon Salmo salar parr tagged with passive integrated transponder tags. Water temperature remained relatively uniform throughout the study site. We found very little movement of recaptured fish in the study site. Fish that were recaptured in the beaver pond displayed faster summer growth rates in both length and mass than fish that were recaptured immediately above or below the pond. We also found that parr in the pond maintained relatively high condition factors, whereas fish above and below the pond appeared to decrease in condition factor throughout the summer. In addition to growth, the maturation rates of age-2 males were higher above the dam than below. This study demonstrates the effect a beaver dam can have on individual growth rates. By influencing growth during sensitive periods, the beaver pond may also influence individual life history pathways. This information could be an important component in ecosystem models that predict the effect of beaver population dynamics on the growth of individual salmonids at the landscape scale. ?? Copyright by the American Fisheries Society 2006.

Electron microscopy investigation of gallium oxide micro/nanowire structures synthesized via vapor phase growth.

PubMed

Wang, Y; Xu, J; Wang, R M; Yu, D P

2004-01-01

Large-scale micro/nanosized Ga(2)O(3) structures were synthesized via a simple vapor p9hase growth method. The morphology of the as-grown structures varied from aligned arrays of smooth nano/microscale wires to composite and complex microdendrites. We present evidence that the formation of the observed structure depends strongly on its position relative to the source materials (the concentration distribution) and on the growth temperature. A growth model is proposed, based on the vapor-solid (VS) mechanism, which can explain the observed morphologies.

The Not-so-Dark Ages: ecology for human growth in medieval and early twentieth century Portugal as inferred from skeletal growth profiles.

PubMed

Cardoso, Hugo F V; Garcia, Susana

2009-02-01

This study attempts to address the issue of relative living standards in Portuguese medieval and early 20th century periods. Since the growth of children provides a good measure of environmental quality for the overall population, the skeletal growth profiles of medieval Leiria and early 20th century Lisbon were compared. Results show that growth in femur length of medieval children did not differ significantly from that of early 20th century children, but after puberty medieval adolescents seem to have recovered, as they have significantly longer femora as adults. This is suggestive of greater potential for catch-up growth in medieval adolescents. We suggest that this results from distinct child labor practices, which impact differentially on the growth of Leiria and Lisbon adolescents. Work for medieval children and adolescents were related to family activities, and care and attention were provided by family members. Conversely, in early 20th century Lisbon children were more often sent to factories at around 12 years of age as an extra source of family income, where they were exploited for their labor. Since medieval and early 20th century children were stunted at an early age, greater potential for catch-up growth in medieval adolescents results from exhausting work being added to modern adolescent's burdens of disease and poor diet, when they entered the labor market. Although early 20th century Lisbon did not differ in overall unfavorable living conditions from medieval Leiria, after puberty different child labor practices may have placed modern adolescents at greater risk of undernutrition and poor growth. 2008 Wiley-Liss, Inc.

Ambient aging of rhenium filaments used in thermal ionization mass spectrometry: Growth of oxo-rhenium crystallites and anti-aging strategies.

PubMed

Mannion, Joseph M; Wellons, Matthew S; Shick, Charles R; Fugate, Glenn A; Powell, Brian A; Husson, Scott M

2017-01-01

Degassing is a common preparation technique for rhenium filaments used for thermal ionization mass spectrometric analysis of actinides, including plutonium. Although optimization studies regarding degassing conditions have been reported, little work has been done to characterize filament aging after degassing. In this study, the effects of filament aging after degassing were explored to determine a "shelf-life" for degassed rhenium filaments, and methods to limit filament aging were investigated. Zone-refined rhenium filaments were degassed by resistance heating under high vacuum before exposure to ambient atmosphere for up to 2 months. After degassing the nucleation and preferential growth of oxo-rhenium crystallites on the surface of polycrystalline rhenium filaments was observed by atomic force microscopy and scanning electron microscopy (SEM). Compositional analysis of the crystallites was conducted using SEM-Raman spectroscopy and SEM energy dispersive X-ray spectroscopy, and grain orientation at the metal surface was investigated by electron back-scatter diffraction mapping. Spectra collected by SEM-Raman suggest crystallites are composed primarily of perrhenic acid. The relative extent of growth and crystallite morphology were found to be grain dependent and affected by the dissolution of carbon into filaments during annealing (often referred to as carbonization or carburization). Crystallites were observed to nucleate in region specific modes and grow over time through transfer of material from the surface. Factors most likely to affect the rates of crystallite growth include rhenium substrate properties such as grain size, orientation, levels of dissolved carbon, and relative abundance of defect sites; as well as environmental factors such as length of exposure to oxygen and relative humidity. Thin (∼180 nm) hydrophobic films of poly(vinylbenzyl chloride) were found to slow the growth of oxo-rhenium crystallites on the filament surfaces and may serve as

Growth of the European abalone ( Haliotis tuberculata L.) in situ: Seasonality and ageing using stable oxygen isotopes

NASA Astrophysics Data System (ADS)

Roussel, Sabine; Huchette, Sylvain; Clavier, Jacques; Chauvaud, Laurent

2011-02-01

The ormer, Haliotis tuberculata is the only European abalone species commercially exploited. The determination of growth and age in the wild is an important tool for fisheries and aquaculture management. However, the ageing technique used in the past in the field is unreliable. The stable oxygen isotope composition ( 18O/ 16O) of the shell depends on the temperature and oxygen isotope composition of the ambient sea water. The stable oxygen isotope technique, developed to study paleoclimatological changes in shellfish, was applied to three H. tuberculata specimens collected in north-west Brittany. For the specimens collected, the oxygen isotope ratios of the shell reflected the seasonal cycle in the temperature. From winter-to-winter cycles, estimates of the age and the annual growth increment, ranging from 13 to 55 mm per year were obtained. This study shows that stable oxygen isotopes can be a reliable tool for ageing and growth studies of this abalone species in the wild, and for validating other estimates.

Growth mechanisms, polytypism, and real structure of kaolinite microcrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samotoin, N. D., E-mail: samnik@igem.ru

2008-09-15

The mechanisms of growth of kaolinite microcrystals (0.1-5.0 {mu}m in size) at deposits related to the cluvial weathering crust, as well as to the low-temperature and medium-temperature hydrothermal processes of transformations of minerals in different rocks in Russia, Kazakhstan, Ukraine, Czechia, Vietnam, India, Cuba, and Madagascar, are investigated using transmission electron microscopy and vacuum decoration with gold. It is established that kaolinite microcrystals grow according to two mechanisms: the mechanism of periodic formation of two-dimensional nuclei and the mechanism of spiral growth. The spiral growth of kaolinite microcrystals is dominant and occurs on steps of screw dislocations that differ inmore » sign and magnitude of the Burgers vector along the c axis. The layered growth of kaolinite originates from a widespread source in the form of a step between polar (+ and -) dislocations, i.e., a growth analogue of the Frank-Read dislocation source. The density of growth screw dislocations varies over a wide range and can be as high as {approx}10{sup 9} cm{sup -2}. Layered stepped kaolinite growth pyramids for all mechanisms of growth on the (001) face of kaolinite exhibit the main features of the triclinic 1Tc and real structures of this mineral.« less

Wood density of young-growth western hemlock: relation to ring age, radial growth, stand density, and site quality.

Treesearch

Dean S. DeBell; Ryan Singleton; Barbara L. Gartner; David D. Marshall

2004-01-01

Breast-high stem sections were sampled from 56 western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees growing in 15 plots representing a wide range of tree and site conditions in northwestern Oregon. Growth and wood density traits of individual rings were measured via X-ray densitometry, and relationships of ring density and its components to age...

Mind-Reading Ability and Structural Connectivity Changes in Aging

PubMed Central

Cabinio, Monia; Rossetto, Federica; Blasi, Valeria; Savazzi, Federica; Castelli, Ilaria; Massaro, Davide; Valle, Annalisa; Nemni, Raffaello; Clerici, Mario; Marchetti, Antonella; Baglio, Francesca

2015-01-01

The Mind-Reading ability through the eyes is an important component of the affective Theory of Mind (ToM), which allows people to infer the other’s mental state from the eye gaze. The aim of the present study was to investigate to which extent age-associated structural brain changes impact this ability and to determine if this association is related to executive functions in elderly subjects. For this purpose, Magnetic Resonance Imaging was used to determine both gray matter and white matter (WM) areas associated with aging. The resulting areas have been included in a subsequent correlation analysis to detect the brain regions whose structure was associated with the Mind-Reading ability through the eyes, assessed with the Italian version of the “Reading the Mind in the Eyes” (RME) test, in a sample of 36 healthy subjects ranging from 24 to 79 years of age. The analysis resulted in three important findings: (1) the performance to the RME test is relatively stable across the decades 20–70 (despite a slight decrease of this ability with aging) and independent from executive functions; (2) structural brain imaging demonstrated the involvement of a great number of cortical ToM areas for the execution of the RME test: the bilateral precentral gyrus, the bilateral posterior insula, the left superior temporal gyrus and the left inferior frontal gyrus, which also showed a significant volume decrease with age; (3) an age and task-related decline in WM connectivity on left fronto-temporal portion of the brain. Our results confirm the age-related structural modifications of the brain and show that these changes have an influence on the Mind-Reading ability through the eyes. PMID:26635702

Effects of cyclic structure inhibitors on the morphology and growth of tetrahydrofuran hydrate crystals

NASA Astrophysics Data System (ADS)

Li, Sijia; Wang, Yanhong; Lang, Xuemei; Fan, Shuanshi

2013-08-01

Morphology and growth of hydrate crystals with cyclic structure inhibitors at a hydrate-liquid interface were directly observed through a microscopic manipulating apparatus. Tetrahydrofuran (THF) hydrate was employed as an objective. The effects of four kind of cyclic structure inhibitors, polyvinylpyrrolidone (PVP), poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine) (PVPP), poly(2-vinyl pyridine-co-N-vinylcaprolactam) (PVPC) and poly(N-vinylcaprolactam) (PVCap), were investigated. Morphological patterns between each hydrate crystal growth from hydrate-liquid interface into droplet were found differ significantly. Lamellar structure growth of hydrate crystal was observed without inhibitor, while with PVP was featheriness-like, PVPP was like long dendritic crystal, PVPC was Mimosa pudica leaf-like and PVCap was like weeds. The growth rate of hydrate crystal without inhibitor was 0.00498 mm3/s, while with PVPP, PVPC and PVCap, were 0.00339 mm3/s, 0.00350 mm3/s, 0.00386 mm3/s and 0.00426 mm3/s, respectively. Cyclic structure inhibitors can decrease the growth rate, degree of reduction in growth rate of hydrate crystals decrease with the increase of cylinder number.

A kinetic theory for age-structured stochastic birth-death processes

NASA Astrophysics Data System (ADS)

Chou, Tom; Greenman, Chris

Classical age-structured mass-action models such as the McKendrick-von Foerster equation have been extensively studied but they are structurally unable to describe stochastic fluctuations or population-size-dependent birth and death rates. Conversely, current theories that include size-dependent population dynamics (e.g., carrying capacity) cannot be easily extended to take into account age-dependent birth and death rates. In this paper, we present a systematic derivation of a new fully stochastic kinetic theory for interacting age-structured populations. By defining multiparticle probability density functions, we derive a hierarchy of kinetic equations for the stochastic evolution of an aging population undergoing birth and death. We show that the fully stochastic age-dependent birth-death process precludes factorization of the corresponding probability densities, which then must be solved by using a BBGKY-like hierarchy. Our results generalize both deterministic models and existing master equation approaches by providing an intuitive and efficient way to simultaneously model age- and population-dependent stochastic dynamics applicable to the study of demography, stem cell dynamics, and disease evolution. NSF.

Unintended pregnancy and interpregnancy interval by maternal age, National Survey of Family Growth.

PubMed

Ahrens, Katherine A; Thoma, Marie E; Copen, Casey E; Frederiksen, Brittni N; Decker, Emily J; Moskosky, Susan

2018-03-01

The relationship between unintended pregnancy and interpregnancy interval (IPI) across maternal age is not clear. Using data from the National Survey of Family Growth, we estimated the percentages of pregnancies that were unintended among IPI groups (<6, 6-11, 12-17, 18-23, 24+ months) by maternal age at last live birth (15-19, 20-24, 25-29, 30-44 years). Approximately 40% of pregnancies were unintended and 36% followed an IPI<18 months. Within each maternal age group, the percentage of pregnancies that were unintended decreased as IPI increased. Unintended pregnancies are associated with shorter IPI across the reproductive age spectrum. Published by Elsevier Inc.

Water abstraction affects abundance, size-structure and growth of two threatened cyprinid fishes

PubMed Central

Merciai, Roberto; Molons-Sierra, Carlota; Sabater, Sergi; García-Berthou, Emili

2017-01-01

Hydrologic alteration is a major threat to freshwater biota, and particularly fish, in many river courses around the world. We analyzed and compared the effects of water abstraction on two threatened cyprinid fishes of contrasting ecology (the Mediterranean barbel Barbus meridionalis and the Catalan chub Squalius laietanus) in a Mediterranean stream. We compared abundance, size-structure, growth, and condition of both species across perennial and artificially intermittent reaches affected by water abstraction. Both species were less abundant, had scarce large individuals, and displayed slower growth rates (length-at-age) in intermittent reaches, showing clear detrimental effects of water diversion. Mixed-effect models of scale increments showed variation among individuals and among sites, years and age classes for both species. The larger-sized, water-column species (chub) disappeared or was rare in many intermittent reaches. The barbel present in intermittent reaches showed better somatic condition than in sites with permanent flow, perhaps due to reduced competition after rewetting or colonization by better fitted individuals. This benthic, rheophilic species seems more resilient to moderate water abstraction than chub. Many effects of water flow intermittency were only detected on fish life-history traits when accounting for natural, often non-linear, variation, along upstream-downstream gradients. Our results suggest that abundance was the strongest indicator of effects of water abstraction on fish populations, whereas condition was a more labile trait, rapidly recovering from anthropogenic disturbance. PMID:28414787

Growth and nutritional status of school age children of three communities from Yucatan, Mexico.

PubMed

Azcorra, Hugo; Vaizquez-Vdzquez, Adriana; Baqueiro Ctirdenas, Josi Enrique; Salazar-Rendon, Juan Carlos

2016-06-01

In Mexico, the nutritional status of school age children it is still a public health problem, particularly in the country southeast where malnutrition is alarming. Yucatan state, in Mexico, has one of the highest chronic undernutrition (stunting) and overweight/obesity prevalences. The aim of this study was to describe the growth and nutritional status of a sample of school children (6 - 12 years old) from three rural communities in Yucatan. Between November and December 2014 we obtained height, sitting height, weight, waist circumference (WC) and tricipital skinfold, and calculate leg length, body mass index (BMI) and body fat percentage of a sample of 144 children (6 - 12 years old) in three communities in Yucatan. The 14% of the total sample showed low height for age and 16% and 21% showed exceeded BMI and WC respectively. These data show the coexistence of both extremes of malnutrition. Significant differences in measures of growth and nutritional status categories were found between communities. Factors such as the production and merchandising of local foods, migration (rural-to-urban, regional and international) as well as differences in infraestructure investment in social support appear to be associated with variaticins in the growth and nutritional stattus of school age children analyzed.

Structure of rat acidic fibroblast growth factor at 1.4 Å resolution

PubMed Central

Kulahin, Nikolaj; Kiselyov, Vladislav; Kochoyan, Arthur; Kristensen, Ole; Kastrup, Jette Sandholm; Berezin, Vladimir; Bock, Elisabeth; Gajhede, Michael

2007-01-01

Fibroblast growth factors (FGFs) constitute a family of 22 structurally related heparin-binding polypeptides that are involved in the regulation of cell growth, survival, differentiation and migration. Here, a 1.4 Å resolution X-ray structure of rat FGF1 is presented. Two molecules are present in the asymmetric unit of the crystal and they coordinate a total of five sulfate ions. The structures of human, bovine and newt FGF1 have been published previously. Human and rat FGF1 are found to have very similar structures. PMID:17277441

Electrical, structural and morphological properties of chemically sprayed F-doped ZnO films: effect of the ageing-time of the starting solution, solvent and substrate temperature

NASA Astrophysics Data System (ADS)

Guillén-Santiago, A.; Olvera, M. De La L.; Maldonado, A.; Asomoza, R.; Acosta, D. R.

2004-04-01

Conductive and highly transparent fluorine-doped zinc oxide (ZnO:F) thin films were deposited onto glass substrates by the chemical spray technique, using zinc acetate and hydrofluoric acid as precursors. Electrical, structural, morphological and optical characteristics were analyzed as a function of the ageing-time of the starting solution, alcoholic solvent type (methanol or ethanol) and the substrate temperature. The results show that these variables play a crucial role on the physical properties measured. The growth rates obtained were of 3 nm/s, showing that the chemical species involved are adequate for the film growth. The effect of the solution ageing-time on the electrical properties was monitored along three weeks. A gradual resistivity decrease with the ageing-time was observed, until a minimum value is reached, at 7 or 9 days depending on the alcohol employed. Films deposited after this time have resistivity values slightly higher. All the films were polycrystalline, with a hexagonal wurtzite structure whose preferential growth is strongly dependent on the deposition variables. Under optimal deposition conditions, ZnO:F films with a high transmittance in the visible spectrum (>85%), resistivity as low as 7 × 10-3 cm and maximum electronic mobility around of 4 cm2/(V-s) were obtained.

Age, growth and reproduction of Sarcocheilichthys nigripinnis from the Qingyi Stream in the Huangshan Mountains.

PubMed

Yan, Yunzhi; Xu, Yinsheng; Chu, Ling; He, Shan; Chen, Yifeng

2012-06-01

Identifying the life-history strategies of fish and their associations with the surrounding environment is the basic foundation in the conservation and sustainable utilization of fish species. We examined the age, growth, and reproduction of Sarcocheilichthys nigripinnis using 352 specimens collected monthly from May 2009 to April 2010 in the Qingyi Stream. We found the sex ratio of this study population was 0.58:1 (female: male), significantly different from expected 1:1. Females and males both comprised four age groups. The annuli on the scales were formed during February and March. No obvious between-sex difference was observed in length-weight and length-scale-radius relationships. The total length in back-calculation significantly increased with age for both sexes, but did not differ significantly at each age between the two sexes. An inflection point was observed in the growth curves given by the von Bertalanffy growth function for total weight. At this inflection point, fish were 3.95 years. Both sexes reach their 50% sex maturity at age 2, when females and males were 94.7 mm and 103.0 mm total length. The temporal pattern of the gonado-somatic index corresponded to a spawning period that occurred from April through July. The non-synchronicity of egg diameter in each mature ovary during the breeding period suggested these fish may be batch spawners. The absolute fecundity increased significantly with total length and weight, whereas no significant correlation was observed between the relative fecundity and body size.

Changing stand structure and regional growth reductions in Georgia's natural pine stands

Treesearch

W.A. Bechtold; G.A. Ruark; F.T. Lloyd

1991-01-01

Forest Inventory and Analysis (FIA) data indicate reductions in the growth of naturally regenerated pines in Georgia between the two latest measurement periods (1961-1972 vs. 1972-1982). Analysis of Covariance was used to adjust stand-level basal area growth rates for differences between periods in stand age, stand density, site index, mortality, and hardwood...

Age and growth of the knobbed whelk Busycon carica (Gmelin 1791) in South Carolina subtidal waters

USGS Publications Warehouse

Eversole, A.G.; Anderson, W.D.; Isely, J.J.

2008-01-01

Knobbed whelk, Busycon carica (Gmelin, 1791), age and growth were estimated using tagged and recaptured individuals (n = 396) from areas off South Carolina coastal islands. Recaptured whelks were at large an average of 298 d (4-2,640 d). Growth, an increase in shell length (SL), was evident in 24% of the recaptured whelks, whereas 29% of recaptured individuals were the same size as when released and 47% were smaller than the released size. Mean growth rate was <0.001 mm SL/d and 0.022 mm SL/d if decreases in SL were assumed to be zero. Smaller whelks (???90 mm SL) at large for over one year grew seven times faster than larger whelks. The von Bertalanffy growth model: SL1 = 159.5(1 - e-0.0765(t+0.4162)), was developed from the mark - recapture whelks exhibiting growth. Based on a South Carolina minimum legal size of 102 mm SL, whelks recruit into the fishery at 13 y of age. The longevity, large size at maturity and slow growth suggest the potential for over harvest of knobbed whelk. Future whelk management plans may wish to consider whether economically viable commercial harvest can be sustainable.

A Study of Correlation of Various Growth Indicators with Chronological Age.

PubMed

Singh, Sarabjeet; Sandhu, Navreet; Puri, Taruna; Gulati, Ritika; Kashyap, Rita

2015-01-01

The aim of this study was to assess the relationship of chronological age with cervical vertebrae skeletal maturation, frontal sinus width and antegonial notch depth and a correlation, if any, among the three variables. The samples were derived from lateral cephalometric radiographs of 80 subjects (40 males, 40 females; age range: 10 to 19 years). Cervical vertebral development was evaluated by the method of Hassel and Farman, frontal sinus width was measured by the method described by Ertürk and antegonial notch depth as described by Singer et al. The Pearson's correlation coefficients were estimated to assess the relationship of chronological age with cervical vertebrae skeletal maturation, frontal sinus width and antegonial notch depth. The Pearson's correlation coefficient were 0.855 (p < 0.001) between chronological age and cervical vertebrae skeletal maturation, and 0.333 (p < 0.001) between chronological age and frontal sinus width. A highly significant positive correlation was found between chronological age and cervical vertebrae skeletal maturation, and between chronological age and frontal sinus width. Nonsignificant correlation was found between chronological age and antegonial notch depth. How to cite this article: Singh S, Sandhu N, Puri T, Gulati R, Kashyap R. A Study of Correlation of Various Growth Indicators with Chronological Age. Int J Clin Pediatr Dent 2015;8(3): 190-195.

Associations between education and brain structure at age 73 years, adjusted for age 11 IQ

PubMed Central

Dickie, David Alexander; Ritchie, Stuart J.; Karama, Sherif; Pattie, Alison; Royle, Natalie A.; Corley, Janie; Aribisala, Benjamin S.; Valdés Hernández, Maria; Muñoz Maniega, Susana; Starr, John M.; Bastin, Mark E.; Evans, Alan C.; Wardlaw, Joanna M.; Deary, Ian J.

2016-01-01

Objective: To investigate how associations between education and brain structure in older age were affected by adjusting for IQ measured at age 11. Methods: We analyzed years of full-time education and measures from an MRI brain scan at age 73 in 617 community-dwelling adults born in 1936. In addition to average and vertex-wise cortical thickness, we measured total brain atrophy and white matter tract fractional anisotropy. Associations between brain structure and education were tested, covarying for sex and vascular health; a second model also covaried for age 11 IQ. Results: The significant relationship between education and average cortical thickness (β = 0.124, p = 0.004) was reduced by 23% when age 11 IQ was included (β = 0.096, p = 0.041). Initial associations between longer education and greater vertex-wise cortical thickness were significant in bilateral temporal, medial-frontal, parietal, sensory, and motor cortices. Accounting for childhood intelligence reduced the number of significant vertices by >90%; only bilateral anterior temporal associations remained. Neither education nor age 11 IQ was significantly associated with total brain atrophy or tract-averaged fractional anisotropy. Conclusions: The association between years of education and brain structure ≈60 years later was restricted to cortical thickness in this sample; however, the previously reported associations between longer education and a thicker cortex are likely to be overestimates in terms of both magnitude and distribution. This finding has implications for understanding, and possibly ameliorating, life-course brain health. PMID:27664981

Associations between education and brain structure at age 73 years, adjusted for age 11 IQ.

PubMed

Cox, Simon R; Dickie, David Alexander; Ritchie, Stuart J; Karama, Sherif; Pattie, Alison; Royle, Natalie A; Corley, Janie; Aribisala, Benjamin S; Valdés Hernández, Maria; Muñoz Maniega, Susana; Starr, John M; Bastin, Mark E; Evans, Alan C; Wardlaw, Joanna M; Deary, Ian J

2016-10-25

To investigate how associations between education and brain structure in older age were affected by adjusting for IQ measured at age 11. We analyzed years of full-time education and measures from an MRI brain scan at age 73 in 617 community-dwelling adults born in 1936. In addition to average and vertex-wise cortical thickness, we measured total brain atrophy and white matter tract fractional anisotropy. Associations between brain structure and education were tested, covarying for sex and vascular health; a second model also covaried for age 11 IQ. The significant relationship between education and average cortical thickness (β = 0.124, p = 0.004) was reduced by 23% when age 11 IQ was included (β = 0.096, p = 0.041). Initial associations between longer education and greater vertex-wise cortical thickness were significant in bilateral temporal, medial-frontal, parietal, sensory, and motor cortices. Accounting for childhood intelligence reduced the number of significant vertices by >90%; only bilateral anterior temporal associations remained. Neither education nor age 11 IQ was significantly associated with total brain atrophy or tract-averaged fractional anisotropy. The association between years of education and brain structure ≈60 years later was restricted to cortical thickness in this sample; however, the previously reported associations between longer education and a thicker cortex are likely to be overestimates in terms of both magnitude and distribution. This finding has implications for understanding, and possibly ameliorating, life-course brain health. © 2016 American Academy of Neurology.

Age, differential growth and mortality rates in unexploited populations of Florida gar, an apex predator in the Florida Everglades

USGS Publications Warehouse

Murie, D.J.; Parkyn, D.C.; Nico, L.G.; Herod, J.J.; Loftus, W.F.

2009-01-01

Florida gar, Lepisosteus platyrhincus DeKay, were sampled in two canal systems in south Florida during 2000-2001 to estimate age, growth and mortality as part of the Everglades ecosystem-restoration effort. Tamiami (C-4) and L-31W canal systems had direct connections to natural wetlands of the Everglades and harboured large Florida gar populations. Of 476 fish aged, maximum ages were 19 and 10years for females and males, respectively. Maximum sizes were also larger for females compared with males (817 vs 602 mm total length). Overall, female Florida gar from both Tamiami and L-31W were larger at age than males from L-31W that, in turn, were larger at any given age than males from Tamiami. Females also had lower rates of annual mortality (Z = 0.21) than males from L-31W (Z = 0.31) or males from Tamiami (Z = 0.54). As a large and long-lived apex predator in the Everglades, Florida gar may structure lower trophic levels. Regional- and sex-specific population parameters for Florida gar will contribute to the simulation models designed to evaluate Everglades restoration alternatives. ?? 2009 Blackwell Publishing Ltd.

Growth and development in school-age children from Rostov region, Russia: Comparison between urban and rural settings.

PubMed

Voynov, V B; Kulba, S N; Arapova, Yu Yu

2017-12-01

The purposes of the current study were: (1) to describe growth and physical development and establish norms for schoolchildren from Rostov region in Russia; (2) to compare major characteristics of development between urban and rural children by sex and age. Nearly 200,000 children (198,712) aged between 7 and 17 years from 232 urban and rural schools of Rostov region (Southern Federal District of Russia) participated in the study. School age is a period of intensive growth and physiological and psychological development. Irregularities of personal development are caused by a multitude of factors, such as sex differences, heredity, socio-economic status of a family, standard of living, particular environmental conditions, and lifestyle. It has been established that children from the Southern Federal District of Russia had body mass index values higher than age-appropriate norms for all Russians (Total Russian, Rudnev et al., 2014) and World Health Organization charts. Children from urban settings were taller and heavier than children from rural settings. Sex is one of the most influential factors which play key role in determining specific characteristics of growth and personal development. According to our results, boys and girls both had similar age-related changes in weight and height, but their respective dynamics differed. Girls' height and weight values accelerated at the age 10 to 12 years and plateaued after the age fourteen, whereas in boys height and weight steadily increased with age, showing slight acceleration at the age 12 to 13 years, and reached a plateau by the age of seventeen. Copyright © 2017 Elsevier GmbH. All rights reserved.

Lattice Modeling of Early-Age Behavior of Structural Concrete.

PubMed

Pan, Yaming; Prado, Armando; Porras, Rocío; Hafez, Omar M; Bolander, John E

2017-02-25

The susceptibility of structural concrete to early-age cracking depends on material composition, methods of processing, structural boundary conditions, and a variety of environmental factors. Computational modeling offers a means for identifying primary factors and strategies for reducing cracking potential. Herein, lattice models are shown to be adept at simulating the thermal-hygral-mechanical phenomena that influence early-age cracking. In particular, this paper presents a lattice-based approach that utilizes a model of cementitious materials hydration to control the development of concrete properties, including stiffness, strength, and creep resistance. The approach is validated and used to simulate early-age cracking in concrete bridge decks. Structural configuration plays a key role in determining the magnitude and distribution of stresses caused by volume instabilities of the concrete material. Under restrained conditions, both thermal and hygral effects are found to be primary contributors to cracking potential.

Lattice Modeling of Early-Age Behavior of Structural Concrete

PubMed Central

Pan, Yaming; Prado, Armando; Porras, Rocío; Hafez, Omar M.; Bolander, John E.

2017-01-01

The susceptibility of structural concrete to early-age cracking depends on material composition, methods of processing, structural boundary conditions, and a variety of environmental factors. Computational modeling offers a means for identifying primary factors and strategies for reducing cracking potential. Herein, lattice models are shown to be adept at simulating the thermal-hygral-mechanical phenomena that influence early-age cracking. In particular, this paper presents a lattice-based approach that utilizes a model of cementitious materials hydration to control the development of concrete properties, including stiffness, strength, and creep resistance. The approach is validated and used to simulate early-age cracking in concrete bridge decks. Structural configuration plays a key role in determining the magnitude and distribution of stresses caused by volume instabilities of the concrete material. Under restrained conditions, both thermal and hygral effects are found to be primary contributors to cracking potential. PMID:28772590

Early childhood growth patterns and school-age respiratory resistance, fractional exhaled nitric oxide and asthma.

PubMed

Casas, Maribel; den Dekker, Herman T; Kruithof, Claudia J; Reiss, Irwin K; Vrijheid, Martine; de Jongste, Johan C; Jaddoe, Vincent W V; Duijts, Liesbeth

2016-12-01

Greater infant weight gain is associated with lower lung function and increased risk of childhood asthma. The role of early childhood peak growth patterns is unclear. We assessed the associations of individually derived early childhood peak growth patterns with respiratory resistance, fractional exhaled nitric oxide, wheezing patterns, and asthma until school-age. We performed a population-based prospective cohort study among 5364 children. Repeated growth measurements between 0 and 3 years of age were used to derive standard deviation scores (s.d.s) of peak height and weight velocities (PHV and PWV, respectively), and body mass index (BMI) and age at adiposity peak. Respiratory resistance and fractional exhaled nitric oxide were measured at 6 years of age. Wheezing patterns and asthma were prospectively assessed by annual questionnaires. We also assessed whether any association was explained by childhood weight status. Greater PHV was associated with lower respiratory resistance [Z-score (95% CI): -0.03 (-0.04, -0.01) per s.d.s increase] (n = 3382). Greater PWV and BMI at adiposity peak were associated with increased risks of early wheezing [relative risk ratio (95% CI): 1.11 (1.06, 1.16), 1.26 (1.11, 1.43), respectively] and persistent wheezing [relative risk ratio (95% CI): 1.09 (1.03, 1.16), 1.37 (1.17, 1.60), respectively] (n = 3189 and n = 3005, respectively). Childhood weight status partly explained these associations. No other associations were observed. PWV and BMI at adiposity peak are critical for lung developmental and risk of school-age wheezing. Follow-up studies at older ages are needed to elucidate whether these effects persist at later ages. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Network structure impacts global commodity trade growth and resilience.

PubMed

Kharrazi, Ali; Rovenskaya, Elena; Fath, Brian D

2017-01-01

Global commodity trade networks are critical to our collective sustainable development. Their increasing interconnectedness pose two practical questions: (i) Do the current network configurations support their further growth? (ii) How resilient are these networks to economic shocks? We analyze the data of global commodity trade flows from 1996 to 2012 to evaluate the relationship between structural properties of the global commodity trade networks and (a) their dynamic growth, as well as (b) the resilience of their growth with respect to the 2009 global economic shock. Specifically, we explore the role of network efficiency and redundancy using the information theory-based network flow analysis. We find that, while network efficiency is positively correlated with growth, highly efficient systems appear to be less resilient, losing more and gaining less growth following an economic shock. While all examined networks are rather redundant, we find that network redundancy does not hinder their growth. Moreover, systems exhibiting higher levels of redundancy lose less and gain more growth following an economic shock. We suggest that a strategy to support making global trade networks more efficient via, e.g., preferential trade agreements and higher specialization, can promote their further growth; while a strategy to increase the global trade networks' redundancy via e.g., more abundant free-trade agreements, can improve their resilience to global economic shocks.

Network structure impacts global commodity trade growth and resilience

PubMed Central

Rovenskaya, Elena; Fath, Brian D.

2017-01-01

Global commodity trade networks are critical to our collective sustainable development. Their increasing interconnectedness pose two practical questions: (i) Do the current network configurations support their further growth? (ii) How resilient are these networks to economic shocks? We analyze the data of global commodity trade flows from 1996 to 2012 to evaluate the relationship between structural properties of the global commodity trade networks and (a) their dynamic growth, as well as (b) the resilience of their growth with respect to the 2009 global economic shock. Specifically, we explore the role of network efficiency and redundancy using the information theory-based network flow analysis. We find that, while network efficiency is positively correlated with growth, highly efficient systems appear to be less resilient, losing more and gaining less growth following an economic shock. While all examined networks are rather redundant, we find that network redundancy does not hinder their growth. Moreover, systems exhibiting higher levels of redundancy lose less and gain more growth following an economic shock. We suggest that a strategy to support making global trade networks more efficient via, e.g., preferential trade agreements and higher specialization, can promote their further growth; while a strategy to increase the global trade networks’ redundancy via e.g., more abundant free-trade agreements, can improve their resilience to global economic shocks. PMID:28207790

Associations of Linear Growth and Relative Weight Gain in Early Life with Human Capital at 30 Years of Age.

PubMed

Horta, Bernardo Lessa; Victora, Cesar G; de Mola, Christian Loret; Quevedo, Luciana; Pinheiro, Ricardo Tavares; Gigante, Denise P; Motta, Janaina Vieira Dos Santos; Barros, Fernando C

2017-03-01

To assess the associations of birthweight, nutritional status and growth in childhood with IQ, years of schooling, and monthly income at 30 years of age. In 1982, the 5 maternity hospitals in Pelotas, Brazil, were visited daily and 5914 live births were identified. At 30 years of age, 3701 subjects were interviewed. IQ, years of schooling, and income were measured. On average, their IQ was 98 points, they had 11.4 years of schooling, and the mean income was 1593 reais. After controlling for several confounders, birthweight and attained weight and length/height for age at 2 and 4 years of age were associated positively with IQ, years of years of schooling, and income, except for the association between length at 2 years of age and income. Conditional growth analyses were used to disentangle linear growth from relative weight gain. Conditional length at 2 years of age ≥1 SD score above the expected value, compared with ≥1 SD below the expected, was associated with an increase in IQ (4.28 points; 95% CI, 2.66-5.90), years of schooling (1.58 years; 95% CI, 1.08-2.08), and monthly income (303 Brazilian reais; 95% CI, 44-563). Relative weight gain, above what would be expected from linear growth, was not associated with the outcomes. In a middle-income setting, promotion of linear growth in the first 1000 days of life is likely to increase adult IQ, years of schooling, and income. Weight gain in excess of what is expected from linear growth does not seem to improve human capital. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Students' Physical Growth: Developmental Framework, Physical Dimension.

ERIC Educational Resources Information Center

Patterson, Donna; And Others

Alberta Education's position on the physical growth of students is presented in this paper, which focuses on children's physical growth in the areas of perceptual, structural, and motor development. Each area is first discussed in terms of three age groups: the child from infancy to preschool, the elementary child, and the adolescent. Concluding…

Structural analysis of the human fibroblast growth factor receptor 4 kinase.

PubMed

Lesca, E; Lammens, A; Huber, R; Augustin, M

2014-11-11

The family of fibroblast growth factor receptors (FGFRs) plays an important and well-characterized role in a variety of pathological disorders. FGFR4 is involved in myogenesis and muscle regeneration. Mutations affecting the kinase domain of FGFR4 may cause cancer, for example, breast cancer or rhabdomyosarcoma. Whereas FGFR1-FGFR3 have been structurally characterized, the structure of the FGFR4 kinase domain has not yet been reported. In this study, we present four structures of the kinase domain of FGFR4, in its apo-form and in complex with different types of small-molecule inhibitors. The two apo-FGFR4 kinase domain structures show an activation segment similar in conformation to an autoinhibitory segment observed in the hepatocyte growth factor receptor kinase but different from the known structures of other FGFR kinases. The structures of FGFR4 in complex with the type I inhibitor Dovitinib and the type II inhibitor Ponatinib reveal the molecular interactions with different types of kinase inhibitors and may assist in the design and development of FGFR4 inhibitors. Copyright © 2014 Elsevier Ltd. All rights reserved.

Association of Structural Global Brain Network Properties with Intelligence in Normal Aging

PubMed Central

Fischer, Florian U.; Wolf, Dominik; Scheurich, Armin; Fellgiebel, Andreas

2014-01-01

Higher general intelligence attenuates age-associated cognitive decline and the risk of dementia. Thus, intelligence has been associated with cognitive reserve or resilience in normal aging. Neurophysiologically, intelligence is considered as a complex capacity that is dependent on a global cognitive network rather than isolated brain areas. An association of structural as well as functional brain network characteristics with intelligence has already been reported in young adults. We investigated the relationship between global structural brain network properties, general intelligence and age in a group of 43 cognitively healthy elderly, age 60–85 years. Individuals were assessed cross-sectionally using Wechsler Adult Intelligence Scale-Revised (WAIS-R) and diffusion-tensor imaging. Structural brain networks were reconstructed individually using deterministic tractography, global network properties (global efficiency, mean shortest path length, and clustering coefficient) were determined by graph theory and correlated to intelligence scores within both age groups. Network properties were significantly correlated to age, whereas no significant correlation to WAIS-R was observed. However, in a subgroup of 15 individuals aged 75 and above, the network properties were significantly correlated to WAIS-R. Our findings suggest that general intelligence and global properties of structural brain networks may not be generally associated in cognitively healthy elderly. However, we provide first evidence of an association between global structural brain network properties and general intelligence in advanced elderly. Intelligence might be affected by age-associated network deterioration only if a certain threshold of structural degeneration is exceeded. Thus, age-associated brain structural changes seem to be partially compensated by the network and the range of this compensation might be a surrogate of cognitive reserve or brain resilience. PMID:24465994

Maintenance of muscle mass and load-induced growth in Muscle RING Finger 1 null mice with age.

PubMed

Hwee, Darren T; Baehr, Leslie M; Philp, Andrew; Baar, Keith; Bodine, Sue C

2014-02-01

Age-related loss of muscle mass occurs to varying degrees in all individuals and has a detrimental effect on morbidity and mortality. Muscle RING Finger 1 (MuRF1), a muscle-specific E3 ubiquitin ligase, is believed to mediate muscle atrophy through the ubiquitin proteasome system (UPS). Deletion of MuRF1 (KO) in mice attenuates the loss of muscle mass following denervation, disuse, and glucocorticoid treatment; however, its role in age-related muscle loss is unknown. In this study, skeletal muscle from male wild-type (WT) and MuRF1 KO mice was studied up to the age of 24 months. Muscle mass and fiber cross-sectional area decreased significantly with age in WT, but not in KO mice. In aged WT muscle, significant decreases in proteasome activities, especially 20S and 26S β5 (20-40% decrease), were measured and were associated with significant increases in the maladaptive endoplasmic reticulum (ER) stress marker, CHOP. Conversely, in aged MuRF1 KO mice, 20S or 26S β5 proteasome activity was maintained or decreased to a lesser extent than in WT mice, and no increase in CHOP expression was measured. Examination of the growth response of older (18 months) mice to functional overload revealed that old WT mice had significantly less growth relative to young mice (1.37- vs. 1.83-fold), whereas old MuRF1 KO mice had a normal growth response (1.74- vs. 1.90-fold). These data collectively suggest that with age, MuRF1 plays an important role in the control of skeletal muscle mass and growth capacity through the regulation of cellular stress. © 2013 the Anatomical Society and John Wiley & Sons Ltd.

Implications of Bishop Tuff zircon U-Pb ages for rates of zircon growth and magma accumulation

NASA Astrophysics Data System (ADS)

Reid, M. R.; Schmitt, A. K.

2012-12-01

Rates of geologic processes obtained from natural studies rely on accurate geochronologic information. An important benchmark in geochronology as well as a valuable source of insights into the evolution of voluminous explosive eruptions is the >600 km3 Bishop Tuff (BT). A recently determined weighted mean 206Pb/238U date of 767.1±0.9 ka for a BT zircon population [1] is indistinguishable from the recalibrated 40Ar/39Ar sanidine date of 767.4±2.2 ka [2], potentially providing a key intercalibration point between astronomical and radio-isotopic dating approaches. Consequences of these results are linear zircon growth rates of >1×10-14 cm/sec and magma accumulation rates of >200 km3/ka. In contrast, spatially selective SIMS U-Pb dating of BT zircons yielded mean pre-eruption ages of 850 ka [3], a difference that raises questions about the validity of intercalibration between U-Pb and K-Ar dating methods and the history of magma accumulation. We obtained new SIMS analyses of the BT zircons using more spatially and analytically sensitive methods and verifying our accuracy against the TIMS dated Quaternary zircon 61.308A (2.488±0.002 Ma). Analyses were performed on zircon rims and on oriented cross-sections exposed during optical interferometry-calibrated serial sectioning removing the outermost ~31 μm. Sputtering by a 100 nA ion beam versus the normally employed 10-12 nA beam resulted in enhanced radiogenic Pb yields and analytical uncertainties for Quaternary zircon approaching the U-Pb age reproducibility of the primary zircon standard (~1-2 % for AS3). Ages obtained at ~31 μm depth (representing <5% of crystal growth in most cases) average 892±26ka (MSWD=0.29), corroborating previous evidence for residence times of several tens of ka. Rim ages average 781±22 ka (MSWD=0.61), overlapping Ar/Ar determinations of eruption age and corroborating the importance of near-eruption aged zircon growth. Our results confirm the presence of BT zircon domains that predate

Effect of Zinc Supplementation on Growth Outcomes in Children under 5 Years of Age.

PubMed

Liu, Enju; Pimpin, Laura; Shulkin, Masha; Kranz, Sarah; Duggan, Christopher P; Mozaffarian, Dariush; Fawzi, Wafaie W

2018-03-20

(1) Background: The effects of zinc supplementation on child growth, and prior reviews of these studies, have shown mixed results. We aim to systematically review and meta-analyze randomized controlled trials evaluating effects of preventive zinc supplementation for 3 months or longer during pregnancy or in children up to age 5 years on pregnancy outcomes and child growth; (2) Methods: We searched PubMed, EMBASE, Cochrane Library, Web of Science, and trial registries for eligible trials up to October 10, 2017. Inclusion selection and data extractions were performed independently and in duplicate. Study quality was evaluated by the Cochrane Risk of Bias tool. Findings were pooled using random effects meta-analysis, with heterogeneity assessed by I ² and τ² statistic, stratified analyses, and meta-regression, and publication bias by Egger's and Begg's tests; (3) Results: Seventy-eight trials with 34,352 unique participants were identified, including 24 during pregnancy and 54 in infancy/childhood. Maternal zinc supplementation did not significantly increase birth weight (weighted mean difference (WMD) = 0.08 kg, 95%CI: -0.05, 0.22) or decrease the risk of low birth weight (RR = 0.76, 95%CI: 0.52-1.11). Zinc supplementation after birth increased height (WMD = 0.23 cm, 95%CI: 0.09-0.38), weight (WMD = 0.14 kg, 95%CI: 0.07-0.21), and weight-for-age Z -score (WMD = 0.04, 95%CI: 0.001-0.087), but not height-for-age Z -score (WMD = 0.02, 95%CI: -0.01-0.06) or weight-for-height Z score (WMD = 0.02, 95%CI: -0.03-0.06). Child age at zinc supplementation appeared to modify the effects on height ( P -interaction = 0.002) and HAZ ( P -interaction = 0.06), with larger effects of supplementation starting at age ≥2 years (WMD for height = 1.37 cm, 95%CI: 0.50-2.25; WMD for HAZ = 0.12, 95%CI: 0.05-0.19). No significant effects of supplementation were found on the risk of stunting, underweight or wasting; (4) Conclusion: Although the possibility of publication bias and small

[Growth standardized values and curves based on weight, length/height and head circumference for Chinese children under 7 years of age].

PubMed

Li, Hui

2009-03-01

To construct the growth standardized data and curves based on weight, length/height, head circumference for Chinese children under 7 years of age. Random cluster sampling was used. The fourth national growth survey of children under 7 years in the nine cities (Beijing, Harbin, Xi'an, Shanghai, Nanjing, Wuhan, Fuzhou, Guangzhou and Kunming) of China was performed in 2005 and from this survey, data of 69 760 urban healthy boys and girls were used to set up the database for weight-for-age, height-for-age (length was measured for children under 3 years) and head circumference-for-age. Anthropometric data were ascribed to rigorous methods of data collection and standardized procedures across study sites. LMS method based on BOX-COX normal transformation and cubic splines smoothing technique was chosen for fitting the raw data according to study design and data features, and standardized values of any percentile and standard deviation were obtained by the special formulation of L, M and S parameters. Length-for-age and height-for-age standards were constructed by fitting the same model but the final curves reflected the 0.7 cm average difference between these two measurements. A set of systematic diagnostic tools was used to detect possible biases in estimated percentiles or standard deviation curves, including chi2 test, which was used for reference to evaluate to the goodness of fit. The 3rd, 10th, 25th, 50th, 75th, 90th, 97th smoothed percentiles and -3, -2, -1, 0, +1, +2, +3 SD values and curves of weight-for-age, length/height-for-age and head circumference-for-age for boys and girls aged 0-7 years were made out respectively. The Chinese child growth charts was slightly higher than the WHO child growth standards. The newly established growth charts represented the growth level of healthy and well-nourished Chinese children. The sample size was very large and national, the data were high-quality and the smoothing method was internationally accepted. The new Chinese

Ageing management of french NPP civil work structures

NASA Astrophysics Data System (ADS)

Gallitre, E.; Dauffer, D.

2011-04-01

This paper presents EDF practice about concrete structure ageing management, from the mechanisms analysis to the formal procedure which allows the French company to increase 900 MWe NPP lifetime until 40 years; it will also introduce its action plan for 60 years lifetime extension. This practice is based on a methodology which identifies every ageing mechanism; both plants feedback and state of the art are screened and conclusions are drawn up into an "ageing analysis data sheet". That leads at first to a collection of 57 data sheets which give the mechanism identification, the components that are concerned and an analysis grid which is designed to assess the safety risk. This analysis screens the reference documents describing the mechanism, the design lifetime hypotheses, the associated regulation or codification, the feedback experiences, the accessibility, the maintenance actions, the repair possibility and so one. This analysis has to lead to a conclusion about the risk taking into account monitoring and maintenance. If the data sheet conclusion is not clear enough, then a more detailed report is launched. The technical document which is needed, is a formal detailed report which summarizes every theoretical knowledge and monitoring data: its objective is to propose a solution for ageing management: this solution can include more inspections or specific research development, or additional maintenance. After a first stage on the 900 MWe units, only two generic ageing management detailed reports have been needed for the civil engineering part: one about reactor building containment, and one about other structures which focuses on concrete inflating reactions. The second stage consists on deriving this generic analysis (ageing mechanism and detailed reports) to every plant where a complete ageing report is required (one report for all equipments and structures of the plant, but specific for each reactor). This ageing management is a continuous process because the

Plasmodium falciparum infection and age influence parasite growth inhibition mediated by IgG in Beninese infants.

PubMed

Adamou, Rafiou; Chénou, Francine; Sadissou, Ibrahim; Sonon, Paulin; Dechavanne, Célia; Djilali-Saïah, Abdelkader; Cottrell, Gilles; Le Port, Agnès; Massougbodji, Achille; Remarque, Edmond J; Luty, Adrian J F; Sanni, Ambaliou; Garcia, André; Migot-Nabias, Florence; Milet, Jacqueline; Courtin, David

2016-07-01

Antibodies that impede the invasion of Plasmodium falciparum (P. falciparum) merozoites into erythrocytes play a critical role in anti-malarial immunity. The Growth Inhibition Assay (GIA) is an in vitro measure of the functional capacity of such antibodies to limit erythrocyte invasion and/or parasite growth. Up to now, it is unclear whether growth-inhibitory activity correlates with protection from clinical disease and there are inconsistent results from studies performed with GIA. Studies that have focused on the relationship between IgGs and their in vitro parasite Growth Inhibition Activity (GIAc) in infants aged less than two years old are rare. Here, we used clinical and parasitological data to precisely define symptomatic or asymptomatic infection with P. falciparum in groups of infants followed-up actively for 18 months post-natally. We quantified the levels of IgG1 and IgG3 directed to a panel of candidate P. falciparum vaccine antigens (AMA-1, MSP1, 2, 3 and GLURP) using ELISA and the functional activity of IgG was quantified using GIA. Data were then correlated with individuals' infection status. At 18 months of age, infants harbouring infections at the time of blood sampling had an average 19% less GIAc than those not infected (p=0.004, multivariate linear regression). GIAc decreased from 12 to 18 months of age (p=0.003, Wilcoxon matched pairs test). Antibody levels quantified at 18 months in infants were strongly correlated with their exposure to malarial infection, however GIAc was not correlated with malaria infectious status (asymptomatic and symptomatic groups). In conclusion, both infection status at blood draw and age influence parasite growth inhibition mediated by IgG in the GIA. Both factors must be taken into account when correlations between GIAc and anti-malarial protection or vaccine efficacy have to be made. Copyright © 2016 Elsevier B.V. All rights reserved.

Otolith reading and multi-model inference for improved estimation of age and growth in the gilthead seabream Sparus aurata (L.)

NASA Astrophysics Data System (ADS)

Mercier, Lény; Panfili, Jacques; Paillon, Christelle; N'diaye, Awa; Mouillot, David; Darnaude, Audrey M.

2011-05-01

Accurate knowledge of fish age and growth is crucial for species conservation and management of exploited marine stocks. In exploited species, age estimation based on otolith reading is routinely used for building growth curves that are used to implement fishery management models. However, the universal fit of the von Bertalanffy growth function (VBGF) on data from commercial landings can lead to uncertainty in growth parameter inference, preventing accurate comparison of growth-based history traits between fish populations. In the present paper, we used a comprehensive annual sample of wild gilthead seabream ( Sparus aurata L.) in the Gulf of Lions (France, NW Mediterranean) to test a methodology improving growth modelling for exploited fish populations. After validating the timing for otolith annual increment formation for all life stages, a comprehensive set of growth models (including VBGF) were fitted to the obtained age-length data, used as a whole or sub-divided between group 0 individuals and those coming from commercial landings (ages 1-6). Comparisons in growth model accuracy based on Akaike Information Criterion allowed assessment of the best model for each dataset and, when no model correctly fitted the data, a multi-model inference (MMI) based on model averaging was carried out. The results provided evidence that growth parameters inferred with VBGF must be used with high caution. Hence, VBGF turned to be among the less accurate for growth prediction irrespective of the dataset and its fit to the whole population, the juvenile or the adult datasets provided different growth parameters. The best models for growth prediction were the Tanaka model, for group 0 juveniles, and the MMI, for the older fish, confirming that growth differs substantially between juveniles and adults. All asymptotic models failed to correctly describe the growth of adult S. aurata, probably because of the poor representation of old individuals in the dataset. Multi

Microstructural evolution and IMCs growth behavior of Sn-58Bi-0.25Mo solder joint during aging treatment

NASA Astrophysics Data System (ADS)

Yang, Li; Zhu, Lu; Zhang, Yaocheng; Zhou, Shiyuan; Xiong, Yifeng; Wu, Pengcheng

2018-02-01

The microstructural evolution and IMCs growth behavior of Sn-58Bi and Sn-58Bi-0.25Mo solder joints were investigated. The results showed that the microstructure is coarsened, the IMCs layer thickness is increased and the tensile strength of Sn-58Bi and Sn-58Bi-0.25Mo solder joints is decreased with increasing aging time and temperature. Aging temperature is the key factor that causes the excessive IMCs growth of the solder joint compared with aging time, and the activation energy of IMCs layer growth of Sn-58Bi and Sn-58Bi-0.25Mo solder joints is 48.94 kJ mol-1 and 53.79 kJ mol-1, respectively. During the aging treatment, the microstructure of Sn-58Bi solder joint is refined by adding Mo nanoparticles, and the appropriate IMCs layer thickness and improved mechanical properties are obtained by Sn-58Bi-0.25Mo solder joint.

The evolution of labile traits in sex- and age-structured populations.

PubMed

Childs, Dylan Z; Sheldon, Ben C; Rees, Mark

2016-03-01

Many quantitative traits are labile (e.g. somatic growth rate, reproductive timing and investment), varying over the life cycle as a result of behavioural adaptation, developmental processes and plastic responses to the environment. At the population level, selection can alter the distribution of such traits across age classes and among generations. Despite a growing body of theoretical research exploring the evolutionary dynamics of labile traits, a data-driven framework for incorporating such traits into demographic models has not yet been developed. Integral projection models (IPMs) are increasingly being used to understand the interplay between changes in labile characters, life histories and population dynamics. One limitation of the IPM approach is that it relies on phenotypic associations between parents and offspring traits to capture inheritance. However, it is well-established that many different processes may drive these associations, and currently, no clear consensus has emerged on how to model micro-evolutionary dynamics in an IPM framework. We show how to embed quantitative genetic models of inheritance of labile traits into age-structured, two-sex models that resemble standard IPMs. Commonly used statistical tools such as GLMs and their mixed model counterparts can then be used for model parameterization. We illustrate the methodology through development of a simple model of egg-laying date evolution, parameterized using data from a population of Great tits (Parus major). We demonstrate how our framework can be used to project the joint dynamics of species' traits and population density. We then develop a simple extension of the age-structured Price equation (ASPE) for two-sex populations, and apply this to examine the age-specific contributions of different processes to change in the mean phenotype and breeding value. The data-driven framework we outline here has the potential to facilitate greater insight into the nature of selection and its

On the probabilistic structure of water age

NASA Astrophysics Data System (ADS)

Porporato, Amilcare; Calabrese, Salvatore

2015-05-01

The age distribution of water in hydrologic systems has received renewed interest recently, especially in relation to watershed response to rainfall inputs. The purpose of this contribution is first to draw attention to existing theories of age distributions in population dynamics, fluid mechanics and stochastic groundwater, and in particular to the McKendrick-von Foerster equation and its generalizations and solutions. A second and more important goal is to clarify that, when hydrologic fluxes are modeled by means of time-varying stochastic processes, the age distributions must themselves be treated as random functions. Once their probabilistic structure is obtained, it can be used to characterize the variability of age distributions in real systems and thus help quantify the inherent uncertainty in the field determination of water age. We illustrate these concepts with reference to a stochastic storage model, which has been used as a minimalist model of soil moisture and streamflow dynamics.

Grain-Boundary Engineering for Aging and Slow-Crack-Growth Resistant Zirconia.

PubMed

Zhang, F; Chevalier, J; Olagnon, C; Batuk, M; Hadermann, J; Van Meerbeek, B; Vleugels, J

2017-07-01

Ceramic materials are prone to slow crack growth, resulting in strength degradation over time. Although yttria-stabilized zirconia (Y-TZP) ceramics have higher crack resistance than other dental ceramics, their aging susceptibility threatens their long-term performance in aqueous environments such as the oral cavity. Unfortunately, increasing the aging resistance of Y-TZP ceramics normally reduces their crack resistance. Our recently conducted systematic study of doping 3Y-TZP with various trivalent cations revealed that lanthanum oxide (La 2 O 3 ) and aluminum oxide (Al 2 O 3 ) have the most potent effect to retard the aging kinetics of 3Y-TZP. In this study, the crack-propagation behavior of La 2 O 3 and Al 2 O 3 co-doped 3Y-TZP ceramics was investigated by double-torsion methods. The grain boundaries were examined using scanning transmission electron microscopy and energy-dispersive spectroscopy (STEM-EDS). Correlating these analytic data with hydrothermal aging studies using different doping systems, a strategy to strongly bind the segregated dopant cations with the oxygen vacancies at the zirconia-grain boundary was found to improve effectively the aging resistance of Y-TZP ceramics without affecting the resistance to crack propagation.

Cooperation and age structure in spatial games

NASA Astrophysics Data System (ADS)

Wang, Zhen; Wang, Zhen; Zhu, Xiaodan; Arenzon, Jeferson J.

2012-01-01

We study the evolution of cooperation in evolutionary spatial games when the payoff correlates with the increasing age of players (the level of correlation is set through a single parameter, α). The demographic heterogeneous age distribution, directly affecting the outcome of the game, is thus shown to be responsible for enhancing the cooperative behavior in the population. In particular, moderate values of α allow cooperators not only to survive but to outcompete defectors, even when the temptation to defect is large and the ageless, standard α=0 model does not sustain cooperation. The interplay between age structure and noise is also considered, and we obtain the conditions for optimal levels of cooperation.

Phylogenetic, functional, and structural components of variation in bone growth rate of amniotes.

PubMed

Cubo, Jorge; Legendre, Pierre; de Ricqlès, Armand; Montes, Laëtitia; de Margerie, Emmanuel; Castanet, Jacques; Desdevises, Yves

2008-01-01

The biological features observed in every living organism are the outcome of three sets of factors: historical (inherited by homology), functional (biological adaptation), and structural (properties inherent to the materials with which organs are constructed, and the morphogenetic rules by which they grow). Integrating them should bring satisfactory causal explanations of empirical data. However, little progress has been accomplished in practice toward this goal, because a methodologically efficient tool was lacking. Here we use a new statistical method of variation partitioning to analyze bone growth in amniotes. (1) Historical component. The variation of bone growth rates contains a significant phylogenetic signal, suggesting that the observed patterns are partly the outcome of shared ancestry. (2) Functional causation. High growth rates, although energy costly, may be adaptive (i.e., they may increase survival rates) in taxa showing short growth periods (e.g., birds). In ectothermic amniotes, low resting metabolic rates may limit the maximum possible growth rates. (3) Structural constraint. Whereas soft tissues grow through a multiplicative process, growth of mineralized tissues is accretionary (additive, i.e., mineralization fronts occur only at free surfaces). Bone growth of many amniotes partially circumvents this constraint: it is achieved not only at the external surface of the bone shaft, but also within cavities included in the bone cortex as it grows centrifugally. Our approach contributes to the unification of historicism, functionalism, and structuralism toward a more integrated evolutionary biology.

Growth of equilibrium structures built from a large number of distinct component types.

PubMed

Hedges, Lester O; Mannige, Ranjan V; Whitelam, Stephen

2014-09-14

We use simple analytic arguments and lattice-based computer simulations to study the growth of structures made from a large number of distinct component types. Components possess 'designed' interactions, chosen to stabilize an equilibrium target structure in which each component type has a defined spatial position, as well as 'undesigned' interactions that allow components to bind in a compositionally-disordered way. We find that high-fidelity growth of the equilibrium target structure can happen in the presence of substantial attractive undesigned interactions, as long as the energy scale of the set of designed interactions is chosen appropriately. This observation may help explain why equilibrium DNA 'brick' structures self-assemble even if undesigned interactions are not suppressed [Ke et al. Science, 338, 1177, (2012)]. We also find that high-fidelity growth of the target structure is most probable when designed interactions are drawn from a distribution that is as narrow as possible. We use this result to suggest how to choose complementary DNA sequences in order to maximize the fidelity of multicomponent self-assembly mediated by DNA. We also comment on the prospect of growing macroscopic structures in this manner.

Normal and aging hair biology and structure 'aging and hair'.

PubMed

Goodier, Molly; Hordinsky, Maria

2015-01-01

Much like an individual's hairstyle, hair fibers along the scalp see a number of changes over the course of one's lifetime. As the decades pass, the shine and volume synonymous with youthful hair may give way to thin, dull, and brittle hair commonly associated with aging. These changes are a result of a compilation of genetic and environmental elements influencing the cells of the hair follicle, specifically the hair follicle stem cells and melanocytes. Telomere shortening, decrease in cell numbers, and particular transcription factors have all been implicated in this process. In turn, these molecular alterations lead to structural modifications of the hair fiber, decrease in melanin production, and lengthening of the telogen phase of the hair cycle. Despite this inevitable progression with aging, there exists an array of treatments such as light therapy, minoxidil, and finasteride which have been designed to mitigate the effects of aging, particularly balding and thinning hair. Although each works through a different mechanism, all aim to maintain or potentially restore the youthful quality of hair. © 2015 S. Karger AG, Basel.

Child Weight Growth Trajectory and its Determinants in a Sample of Iranian Children from Birth until 2 Years of Age

PubMed Central

Hosseini, Sayed-Mohsen; Maracy, Mohamad-Reza; Sarrafzade, Sheida; Kelishadi, Roya

2014-01-01

Background: Growth is one of the most important indices in child health. The best and most effective way to investigate child health is measuring the physical growth indices such as weight, height and head circumference. Among these measures, weight growth is the simplest and the most effective way to determine child growth status. Weight trend at a given age is the result of cumulative growth experience, whereas growth velocity represents what is happening at the time. Methods: This longitudinal study was conducted among 606 children repeatedly measured from birth until 2 years of age. We used linear mixed model to analyze repeated measures and to determine factors affecting the growth trajectory. LOWESS smooth curve was used to draw velocity curves. Results: Gender, child rank, birth status and feeding mode had a significant effect on weight trajectory. Boys had higher weight during the study. Infants with exclusive breast feeding had higher weight than other infants. Boys had higher growth velocity up to age 6 month. Breast fed infants had higher growth velocity up to 6 month, but thereafter the velocity was higher in other infants. Conclusions: Many of the studies have investigated child growth, but most of them used cross-sectional design. In this study, we used longitudinal method to determine effective factors on weight trend in children from birth until 2-year-old. The effects of perinatal factors on further growth should be considered for prevention of growth disorders and their late complications. PMID:24829720

Infertility treatment and children's longitudinal growth between birth and 3 years of age

PubMed Central

Yeung, E.H.; Sundaram, R.; Bell, E.M.; Druschel, C.; Kus, C.; Xie, Y.; Buck Louis, G.M.

2016-01-01

STUDY QUESTION Does early childhood growth from birth through to 3 years of age differ by mode of conception? SUMMARY ANSWER Findings suggest early childhood growth was comparable for children irrespective of infertility treatment, but twins conceived with ovulation induction with or without intrauterine insemination (OI/IUI) were slightly smaller than twins conceived without treatment. WHAT IS KNOWN ALREADY Although studies have found that babies conceived with infertility treatment are born lighter and earlier than infants conceived without treatment, little research especially for non-assisted reproductive technology (ART) treatments has focused on their continued growth during early childhood. STUDY DESIGN, SIZE, DURATION Upstate KIDS recruited infants born (2008–2010) to resident upstate New York mothers. Infants were sampled based on birth certificate indication of infertility treatment; specifically, for every singleton conceived by infertility treatment, three singletons without infertility treatment were recruited and matched on region of birth. All multiple births irrespective of treatment were also recruited. Children were prospectively followed, returning questionnaires every 4–6 months until 3 years of age. In total, 3905 singletons, 1129 sets of multiples (96% of whom were twins) enrolled into the study. Analyses included 3440 (88%) singletons (969 conceived with treatment; specifically, 433 with ART and 535 with OI/IUI) and 991 (88%) sets of multiples (439 conceived with treatment; specifically 233 with ART and 206 with OI/IUI) with growth data available. PARTICIPANTS/MATERIALS, SETTING, METHODS Mothers reported infertility treatment use at baseline and children's height and weight from pediatric visits. Self-reported use of ART was previously verified by linkage with the US Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) database. Mixed linear models with cubic splines accounting for age and age�

Age, growth and hatch dates of ingressing larvae and surviving juveniles of Atlantic menhaden Brevoortia tyrannus.

PubMed

Lozano, C; Houde, E D; Wingate, R L; Secor, D H

2012-10-01

Ages, growth and hatch dates of ingressing Brevoortia tyrannus larvae were determined in a 3 year sampling survey at the mouth of the Chesapeake Bay, U.S.A. To determine if otolith-aged cohorts had variable relative survival, hatch dates of summer-caught young-of-the-year (YOY) juveniles collected throughout the Chesapeake Bay were compared with hatch dates of ingressing larvae. Modal total length of ingressing larvae was similar among years: 28 mm in 2005-2006 and 2007-2008, and 30 mm in 2006-2007. Ages of ingressing larvae ranged from 9 to 96 days post hatch (dph); mean ages were similar among years, but significantly older in 2006-2007 (50 dph) than in 2005-2006 (44 dph) and 2007-2008 (46 dph). Larval growth rates differed among years. Earliest growth, when larvae were offshore (0-20 dph), was faster in 2006-2007 (0·62 mm day(-1)), than in 2005-2006 and 2007-2008 (0·55 mm day(-1) in these years). Subsequently, from 30 to 80 dph, growth was slowest in 2006-2007. Hatch dates of ingressing larvae occurred from September to March and 90% (2007-2008) to 98% (2006-2007) had hatched prior to 31 December. In contrast, most surviving YOY juvenile B. tyrannus had hatched in January to February, suggesting selective mortality of early-hatched individuals, apparently during the overwinter, larval to juvenile transition period. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Impact of age and sex on normal left heart structure and function.

PubMed

Hagström, Linn; Henein, Michael Y; Karp, Kjell; Waldenström, Anders; Lindqvist, Per

2017-11-01

Accurate age- and sex-related normal reference values of ventricular structure and function are important to determine the level of dysfunction in patients. The aim of this study therefore was to document normal age range sex-related measurements of LV structural and functional measurements to serve such purpose. We evaluated left ventricular structure and function in 293 healthy subjects between 20 and 90 years with equally distributed gender. Doppler echocardiography was used including measure of both systolic and diastolic functions. Due to systolic LV function, only long axis function correlated with age (r = 0·55, P<0·01) and the correlation was stronger in females. Concerning diastolic function, there was a strong age correlation in all parameters used (r = 0·40-0·74, P<0·001). Due to LV structural changes over age, females showed a larger reduction in end-diastolic volumes, but no or trivial difference in wall thickness after the age of 60 years. Age is associated with significant normal changes in left ventricular structure and function, which should be considered when deciding on normality. These changes are related to systemic arterial changes as well as body stature, thus reflecting overall body ageing process. Furthermore, normal cardiac ageing in females might partly explain the higher prevalence of heart failure with preserved ejection in females. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Spatio-temporal variation in age structure and abundance of the endangered snail kite: Pooling across regions masks a declining and aging population

USGS Publications Warehouse

Reichert, Brian E.; Kendall, William L.; Fletcher, Robert J.; Kitchens, Wiley M.

2016-01-01

While variation in age structure over time and space has long been considered important for population dynamics and conservation, reliable estimates of such spatio-temporal variation in age structure have been elusive for wild vertebrate populations. This limitation has arisen because of problems of imperfect detection, the potential for temporary emigration impacting assessments of age structure, and limited information on age. However, identifying patterns in age structure is important for making reliable predictions of both short- and long-term dynamics of populations of conservation concern. Using a multistate superpopulation estimator, we estimated region-specific abundance and age structure (the proportion of individuals within each age class) of a highly endangered population of snail kites for two separate regions in Florida over 17 years (1997–2013). We find that in the southern region of the snail kite—a region known to be critical for the long-term persistence of the species—the population has declined significantly since 1997, and during this time, it has increasingly become dominated by older snail kites (> 12 years old). In contrast, in the northern region—a region historically thought to serve primarily as drought refugia—the population has increased significantly since 2007 and age structure is more evenly distributed among age classes. Given that snail kites show senescence at approximately 13 years of age, where individuals suffer higher mortality rates and lower breeding rates, these results reveal an alarming trend for the southern region. Our work illustrates the importance of accounting for spatial structure when assessing changes in abundance and age distribution and the need for monitoring of age structure in imperiled species.

Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

Treesearch

Emily J. Silver; Anthony W. D' Amato; Shawn Fraver; Brian J. Palik; John B. Bradford

2013-01-01

The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types....

A Systematic Approach for Identifying Level-1 Error Covariance Structures in Latent Growth Modeling

ERIC Educational Resources Information Center

Ding, Cherng G.; Jane, Ten-Der; Wu, Chiu-Hui; Lin, Hang-Rung; Shen, Chih-Kang

2017-01-01

It has been pointed out in the literature that misspecification of the level-1 error covariance structure in latent growth modeling (LGM) has detrimental impacts on the inferences about growth parameters. Since correct covariance structure is difficult to specify by theory, the identification needs to rely on a specification search, which,…

The influence of head growth in fetal life, infancy, and childhood on intelligence at the ages of 4 and 8 years.

PubMed

Gale, Catharine R; O'Callaghan, Finbar J; Bredow, Maria; Martyn, Christopher N

2006-10-01

We investigated the effects of head growth prenatally, during infancy, and during later periods of development on cognitive function at the ages of 4 and 8 years. We studied 633 term-born children from the Avon Longitudinal Study of Parents and Children cohort whose head circumference was measured at birth and at regular intervals thereafter. Their cognitive function was assessed with the Wechsler Preschool and Primary Scale of Intelligence at the age of 4 years and with the Wechsler Intelligence Scale for Children at the age of 8 years. Linear regression analysis was used to calculate postnatal head growth between successive time points, conditional on previous size, and to examine the relationship between head growth during different periods of development and later IQ. When the influence of head growth was distinguished for different periods, only prenatal growth and growth during infancy were associated with subsequent IQ. At 4 years, after adjustment for parental characteristics, full-scale IQ increased an average of 2.41 points for each 1-SD increase in head circumference at birth and 1.97 points for each 1-SD increase in head growth during infancy, conditional on head size at birth. At 8 years, head circumference at birth was no longer associated with IQ, but head growth during infancy remained a significant predictor, with full-scale IQ increasing an average of 1.56 points for each 1-SD increase in growth. The brain volume a child achieves by the age of 1 year helps determine later intelligence. Growth in brain volume after infancy may not compensate for poorer earlier growth.

Age matters: the effects of volatile organic compounds emitted by Trichoderma atroviride on plant growth.

PubMed

Lee, Samantha; Hung, Richard; Yap, Melanie; Bennett, Joan W

2015-06-01

Studying the effects of microbial volatile organic compounds (VOCs) on plant growth is challenging because the production of volatiles depends on many environmental factors. Adding to this complexity, the method of volatile exposure itself can lead to different responses in plants and may account for some of the contrasting results. In this work, we present an improved experimental design, a plate-within-a-plate method, to study the effects of VOCs produced by filamentous fungi. We demonstrate that the plant growth response to VOCs is dependent on the age of the plant and fungal cultures. Plants exposed to volatiles emitted by 5-day-old Trichoderma atroviride for 14 days exhibited inhibition, while plants exposed to other exposure conditions had growth promotion or no significant change. Using GC-MS, we compared fungal volatile emission of 5-day-old and 14-day-old T. atroviride. As the fungi aged, a few compounds were no longer detected, but 24 new compounds were discovered.

Insulin-like growth factor 2 rescues aging-related memory loss in rats.

PubMed

Steinmetz, Adam B; Johnson, Sarah A; Iannitelli, Dylan E; Pollonini, Gabriella; Alberini, Cristina M

2016-08-01

Aging is accompanied by declines in memory performance, and particularly affects memories that rely on hippocampal-cortical systems, such as episodic and explicit. With aged populations significantly increasing, the need for preventing or rescuing memory deficits is pressing. However, effective treatments are lacking. Here, we show that the level of the mature form of insulin-like growth factor 2 (IGF-2), a peptide regulated in the hippocampus by learning, required for memory consolidation and a promoter of memory enhancement in young adult rodents, is significantly reduced in hippocampal synapses of aged rats. By contrast, the hippocampal level of the immature form proIGF-2 is increased, suggesting an aging-related deficit in IGF-2 processing. In agreement, aged compared to young adult rats are deficient in the activity of proprotein convertase 2, an enzyme that likely mediates IGF-2 posttranslational processing. Hippocampal administration of the recombinant, mature form of IGF-2 rescues hippocampal-dependent memory deficits and working memory impairment in aged rats. Thus, IGF-2 may represent a novel therapeutic avenue for preventing or reversing aging-related cognitive impairments. Copyright © 2016 Elsevier Inc. All rights reserved.

Hydrothermal Growth of ZnO Nanowires on UV-Nanoimprinted Polymer Structures.

PubMed

Park, Sooyeon; Moore, Sean A; Lee, Jaejong; Song, In-Hyouk; Farshchian, Bahador; Kim, Namwon

2018-05-01

Integration of zinc oxide (ZnO) nanowires on miniaturized polymer structures can broaden its application in multi-functional polymer devices by taking advantages of unique physical properties of ZnO nanowires and recent development of polymer microstructures in analytical systems. In this paper, we demonstrate the hydrothermal growth of ZnO nanowires on polymer microstructures fabricated by UV nanoimprinting lithography (NIL) using a polyurethane acrylate (PUA). Since PUA is a siloxane-urethane-acrylate compound containing the alpha-hydroxyl ketone, UV-cured PUA include carboxyl groups, which inhibit and suppress the nucleation and growth of ZnO nanowires on polymer structures. The presence of carboxyl groups in UV-cured PUA was substantiated by Fourier transform infrared spectroscopy (FTIR), and a Ag thin film was deposited on the nanoimprinted polymer structures to limit their inhibitive influence on the growth of ZnO nanowires. Furthermore, the naturally oxidized Ag layer (Ag2O) reduced crystalline lattice mismatches at the interface between ZnO-Ag during the seed annealing process. The ZnO nanowires grown on the Ag-deposited PUA microstructures were found to have comparable morphological characteristics with ZnO nanowires grown on a Si wafer.

The growth and population dynamics of seagrass Thalassia hemprichii in Suli Waters, Ambon Island

NASA Astrophysics Data System (ADS)

Tupan, C. I.; Uneputty, Pr A.

2017-10-01

The objectives of the research were to determined growth of rhizome, age structure, recruitment rate, and mortality rate of Thalassia hemprichii. Data were collected by using reconstruction technique which the measurements were based on past growth history. The age of seagrass was based on plastochrone interval. The recruitment rate was estimated by age structure of living shoots while mortality rate was estimated by age structure of dead shoots. The research was conducted on coastal waters of Suli where divided into two stations with different substrates, namely mixed substrates of sand and mud (S1) and mixed substrates of sand and coral fragment (S2). The growth rate of horizontal rhizome ranged from 4.15-8.68 cm.year-1 whereas the growth rate of vertical rhizome was 1.11-1.16 cm.year-1. The average age of T. hemprichii varied between 3.22-4.15 years. The youngest shoots were found at age 0.38 years and the oldest shoots were 7.82 years. Distribution of age was polymodal which reflecting cohort. The recruitment rate ranged from 0.23-0.54 year-1. Otherwise, the mortality rate ranged from 0.21-0.26 year-1.Seagrass population of T. hemprichii in Suli Waters indicated an increasing condition which shown by higher recruitment rate than mortality rate.

Age-structured mark-recapture analysis: A virtual-population-analysis-based model for analyzing age-structured capture-recapture data

USGS Publications Warehouse

Coggins, L.G.; Pine, William E.; Walters, C.J.; Martell, S.J.D.

2006-01-01

We present a new model to estimate capture probabilities, survival, abundance, and recruitment using traditional Jolly-Seber capture-recapture methods within a standard fisheries virtual population analysis framework. This approach compares the numbers of marked and unmarked fish at age captured in each year of sampling with predictions based on estimated vulnerabilities and abundance in a likelihood function. Recruitment to the earliest age at which fish can be tagged is estimated by using a virtual population analysis method to back-calculate the expected numbers of unmarked fish at risk of capture. By using information from both marked and unmarked animals in a standard fisheries age structure framework, this approach is well suited to the sparse data situations common in long-term capture-recapture programs with variable sampling effort. ?? Copyright by the American Fisheries Society 2006.

Predictors of outcome at 2 years of age after early intrauterine growth restriction.

PubMed

Torrance, H L; Bloemen, M C T; Mulder, E J H; Nikkels, P G J; Derks, J B; de Vries, L S; Visser, G H A

2010-08-01

To examine the relative importance of antenatal and perinatal variables on short- and long-term outcome of preterm growth restricted fetuses with umbilical artery (UA) Doppler abnormalities. This was a cohort study of 180 neonates with birth weight < 10(th) percentile, gestational age at delivery < 34 weeks and abnormal Doppler ultrasound examination of the UA. Various antenatal and perinatal variables were studied in relation to short- and long-term outcome. Neonatal and overall mortality (up to 2 years of age) were predicted by low gestational age at delivery. Neonatal mortality was additionally predicted by absent or reversed UA end-diastolic flow, while the presence of severe neonatal complications and placental villitis were additional predictors of both infant (between 28 days and 1 year of postnatal life) and overall mortality. Placental villitis was found to be the only predictor of necrotizing enterocolitis. Low gestational age at delivery, male sex, abnormal cardiotocography, absent or reversed UA end-diastolic flow and the HELLP syndrome predicted respiratory distress syndrome. Abnormal neurodevelopmental outcome at 2 years was predicted by low birth weight (< 2.3(rd) percentile), fetal acidosis (UA pH < 7.00), and placental villitis. Less advanced gestation at delivery remains an important predictor of short-term outcome in growth-restricted fetuses. In addition, the presence of placental villitis may aid neonatologists in the early identification of infants at increased risk of necrotizing enterocolitis, death and abnormal neurodevelopment at 2 years of age. Abnormal neurodevelopment was related to low weight and acidosis at birth, indicating that the severity of malnutrition and fetal acidosis affect long-term outcome.

Catch-Up Growth Assessment in Long-Term Physically Neglected and Emotionally Abused Preschool Age Male Children.

ERIC Educational Resources Information Center

Olivan, Gonzalo

2003-01-01

A longitudinal study examined 20 neglected and emotionally abused boys (ages 30-42 months) who entered foster residential care and remained a year after initial placement. At placement, children showed a mild form of chronic malnutrition with growth failure. Growth failure was reversible after the first year of stay. (Contains references.)…

Discrete crack growth analysis methodology for through cracks in pressurized fuselage structures

NASA Technical Reports Server (NTRS)

Potyondy, David O.; Wawrzynek, Paul A.; Ingraffea, Anthony R.

1994-01-01

A methodology for simulating the growth of long through cracks in the skin of pressurized aircraft fuselage structures is described. Crack trajectories are allowed to be arbitrary and are computed as part of the simulation. The interaction between the mechanical loads acting on the superstructure and the local structural response near the crack tips is accounted for by employing a hierarchical modeling strategy. The structural response for each cracked configuration is obtained using a geometrically nonlinear shell finite element analysis procedure. Four stress intensity factors, two for membrane behavior and two for bending using Kirchhoff plate theory, are computed using an extension of the modified crack closure integral method. Crack trajectories are determined by applying the maximum tangential stress criterion. Crack growth results in localized mesh deletion, and the deletion regions are remeshed automatically using a newly developed all-quadrilateral meshing algorithm. The effectiveness of the methodology and its applicability to performing practical analyses of realistic structures is demonstrated by simulating curvilinear crack growth in a fuselage panel that is representative of a typical narrow-body aircraft. The predicted crack trajectory and fatigue life compare well with measurements of these same quantities from a full-scale pressurized panel test.

Assessing age- and silt index-independent diameter growth models of individual-tree Southern Appalachian hardwoods

Treesearch

Henry W. Mcnab; Thomas F. Lloyd

1999-01-01

Models of forest vegetation dynamics based on characteristics of individual trees are more suitable to predicting growth of multiple species and age classes than those based on stands. The objective of this study was to assess age- and site index-independent relationships between periodic diameter increment and tree and site effects for 11 major hardwood tree species....

Using SAS PROC CALIS to fit Level-1 error covariance structures of latent growth models.

PubMed

Ding, Cherng G; Jane, Ten-Der

2012-09-01

In the present article, we demonstrates the use of SAS PROC CALIS to fit various types of Level-1 error covariance structures of latent growth models (LGM). Advantages of the SEM approach, on which PROC CALIS is based, include the capabilities of modeling the change over time for latent constructs, measured by multiple indicators; embedding LGM into a larger latent variable model; incorporating measurement models for latent predictors; and better assessing model fit and the flexibility in specifying error covariance structures. The strength of PROC CALIS is always accompanied with technical coding work, which needs to be specifically addressed. We provide a tutorial on the SAS syntax for modeling the growth of a manifest variable and the growth of a latent construct, focusing the documentation on the specification of Level-1 error covariance structures. Illustrations are conducted with the data generated from two given latent growth models. The coding provided is helpful when the growth model has been well determined and the Level-1 error covariance structure is to be identified.

Customized versus population-based growth curves: prediction of low body fat percent at term corrected gestational age following preterm birth.

PubMed

Law, Tameeka L; Katikaneni, Lakshmi D; Taylor, Sarah N; Korte, Jeffrey E; Ebeling, Myla D; Wagner, Carol L; Newman, Roger B

2012-07-01

Compare customized versus population-based growth curves for identification of small-for-gestational-age (SGA) and body fat percent (BF%) among preterm infants. Prospective cohort study of 204 preterm infants classified as SGA or appropriate-for-gestational-age (AGA) by population-based and customized growth curves. BF% was determined by air-displacement plethysmography. Differences between groups were compared using bivariable and multivariable linear and logistic regression analyses. Customized curves reclassified 30% of the preterm infants as SGA. SGA infants identified by customized method only had significantly lower BF% (13.8 ± 6.0) than the AGA (16.2 ± 6.3, p = 0.02) infants and similar to the SGA infants classified by both methods (14.6 ± 6.7, p = 0.51). Customized growth curves were a significant predictor of BF% (p = 0.02), whereas population-based growth curves were not a significant independent predictor of BF% (p = 0.50) at term corrected gestational age. Customized growth potential improves the differentiation of SGA infants and low BF% compared with a standard population-based growth curve among a cohort of preterm infants.

Effect of Isothermal Aging and Thermal Cycling on Interfacial IMC Growth and Fracture Behavior of SnAgCu/Cu Joints

NASA Astrophysics Data System (ADS)

Li, Xiaoyan; Li, Fenghui; Guo, Fu; Shi, Yaowu

2011-01-01

The growth behavior of interfacial intermetallic compounds (IMCs) of SnAgCu/Cu soldered joints was investigated during the reflow process, isothermal aging, and thermal cycling with a focus on the influence of these parameters on growth kinetics. The SnAgCu/Cu soldered joints were isothermally aged at 125°C, 150°C, and 175°C while the thermal cycling was performed within the temperature ranges from -25°C to 125°C and -40°C to 125°C. It was observed that a Cu6Sn5 layer formed, followed by rapid coarsening at the solder/Cu interface during reflowing. The grain size of the interfacial Cu6Sn5 was found to increase with aging time, and the morphology evolved from scallop-like to needle-like to rod-like and finally to particles. The rod-like Ag3Sn phase was formed on the solder side in front of the previously formed Cu6Sn5 layer. However, when subject to an increase of the aging time, the Cu3Sn phase was formed at the interface of the Cu6Sn5 layer and Cu substrate. The IMC growth rate increased with aging temperature for isothermally aged joints. During thermal cycling, the thickness of the IMC layer was found to increase with the number of thermal cycles, although the growth rate was slower than that for isothermal aging. The dwell time at the high-temperature end of the thermal cycles was found to significantly influence the growth rate of the IMCs. The growth of the IMCs, for both isothermal aging and thermal cycling, was found to be Arrhenius with aging temperature, and the corresponding diffusion factor and activation energy were obtained by data fitting. The tensile strength of the soldered joints decreased with increasing aging time. Consequently, the fracture site of the soldered joints migrated from the solder matrix to the interfacial Cu6Sn5 layer. Finally, the shear strength of the joints was found to decrease with both an increase in the number of thermal cycles and a decrease in the dwell temperature at the low end of the thermal cycle.

Communication Breakdown: The Impact of Ageing on Synapse Structure

PubMed Central

Petralia, Ronald S.; Mattson, Mark P.; Yao, Pamela J.

2014-01-01

Impaired synaptic plasticity is implicated in the functional decline of the nervous system associated with ageing. Understanding the structure of ageing synapses is essential to understanding the functions of these synapses and their role in the ageing nervous system. In this review, we summarize studies on ageing synapses in vertebrates and invertebrates, focusing on changes in morphology and ultrastructure. We cover different parts of the nervous system, including the brain, the retina, the cochlea, and the neuromuscular junction. The morphological characteristics of aged synapses could shed light on the underlying molecular changes and their functional consequences. PMID:24495392

Analysis of an age structured model for tick populations subject to seasonal effects

NASA Astrophysics Data System (ADS)

Liu, Kaihui; Lou, Yijun; Wu, Jianhong

2017-08-01

We investigate an age-structured hyperbolic equation model by allowing the birth and death functions to be density dependent and periodic in time with the consideration of seasonal effects. By studying the integral form solution of this general hyperbolic equation obtained through the method of integration along characteristics, we give a detailed proof of the uniqueness and existence of the solution in light of the contraction mapping theorem. With additional biologically natural assumptions, using the tick population growth as a motivating example, we derive an age-structured model with time-dependent periodic maturation delays, which is quite different from the existing population models with time-independent maturation delays. For this periodic differential system with seasonal delays, the basic reproduction number R0 is defined as the spectral radius of the next generation operator. Then, we show the tick population tends to die out when R0 < 1 while remains persistent if R0 > 1. When there is no intra-specific competition among immature individuals due to the sufficient availability of immature tick hosts, the global stability of the positive periodic state for the whole model system of four delay differential equations can be obtained with the observation that a scalar subsystem for the adult stage size can be decoupled. The challenge for the proof of such a global stability result can be overcome by introducing a new phase space, based on which, a periodic solution semiflow can be defined which is eventually strongly monotone and strictly subhomogeneous.

Height growth to age 8 of larch species and hybrids in Wisconsin.

Treesearch

Don E. Riemenschneider; Hans Nienstaedt

1983-01-01

Height growth of tamarack; Siberian, European and Japanese larch; and hybrids between the European and Japanese larch were compared in an 8-year-old test in north-central Wisconsin. Hybrids were tallest and best reached 469 cm (15.4 feet) in mean height at age 8 years from seed. Hybrids exceeded European larch mean height by 12% and tamarack by 23%. Breeding...

Structural modeling of age specific fertility curves in Peninsular Malaysia: An approach of Lee Carter method

NASA Astrophysics Data System (ADS)

Hanafiah, Hazlenah; Jemain, Abdul Aziz

2013-11-01

In recent years, the study of fertility has been getting a lot of attention among research abroad following fear of deterioration of fertility led by the rapid economy development. Hence, this study examines the feasibility of developing fertility forecasts based on age structure. Lee Carter model (1992) is applied in this study as it is an established and widely used model in analysing demographic aspects. A singular value decomposition approach is incorporated with an ARIMA model to estimate age specific fertility rates in Peninsular Malaysia over the period 1958-2007. Residual plots is used to measure the goodness of fit of the model. Fertility index forecast using random walk drift is then utilised to predict the future age specific fertility. Results indicate that the proposed model provides a relatively good and reasonable data fitting. In addition, there is an apparent and continuous decline in age specific fertility curves in the next 10 years, particularly among mothers' in their early 20's and 40's. The study on the fertility is vital in order to maintain a balance between the population growth and the provision of facilities related resources.

Structure of the Soot Growth Region of Laminar Premixer Methane/Oxygen Flames

NASA Technical Reports Server (NTRS)

Xu, F.; Faeth, G. M.

1999-01-01

Soot is a dominant feature of hydrocarbon/air flames, affecting their reaction mechanisms and structure. As a result, soot processes affect capabilities for computational combustion as well as predictions of flame radiation and pollution emissions. Motivated by these observations, the present investigation extended past work on soot growth in laminar premixed flames, seeking to evaluate model predictions of flame structure. Xu et al. report direct measurements of soot residence times, soot concentrations, soot structure, gas temperatures and gas compositions for premixed flames similar to those studied by Harris and Weiner and Ramer et al. respectively. It was found that predictions of major stable gas species concentrations based on mechanisms of Leung and Lindstedt and Frenklach and coworkers, were in good agreement with the measurements. The results were also used to evaluate the hydrogen-abstraction/carbon-addition (HACA) soot growth mechanisms of Frenklach and coworkers and Colket and Hall. It was found that these mechanisms were effective using quite reasonable correlations for the steric factors appearing in the theories. The successful evaluation of the HACA mechanism of soot growth in Refs. 1 and 2 is encouraging but one aspect of this evaluation is a concern. In particular, H-atom concentrations play a crucial role in the HACA mechanism and it was necessary to estimate these concentrations because they were not measured directly. These estimates were made assuming local thermodynamic equilibrium between H, and H based on measured temperatures and H2 concentrations and the equilibrium constant data of Kee et al.. This approach was justified by the flame structure predictions; nevertheless, direct evaluation of equilibrium estimates of H-atom concentrations in the soot growth regions of laminar premixed flames is needed to provide more convincing proof of this behavior. Thus, the objective of the present investigation was to complete new measurements of the

Age Effects on Hypocotyl Mechanics.

PubMed

Saxe, Friederike; Weichold, Susann; Reinecke, Antje; Lisec, Jan; Döring, Anett; Neumetzler, Lutz; Burgert, Ingo; Eder, Michaela

2016-01-01

Numerous studies deal with composition and molecular processes involved in primary cell wall formation and alteration in Arabidopsis. However, it still remains difficult to assess the relation between physiological properties and mechanical function at the cell wall level. The thin and fragile structure of primary cell walls and their large biological variability, partly related to structural changes during growth, make mechanical experiments challenging. Since, to the best of our knowledge, there is no reliable data in the literature about how the properties of the fully elongated zone of hypocotyls change with age. We studied in a series of experiments on two different seed batches the tensile properties the region below the growth zone of 4 to 7 day old etiolated Arabidopsis hypocotyls. Additionally, we analysed geometrical parameters, hypocotyl density and cellulose content as individual traits and their relation to tissue mechanics. No significant differences of the mechanical parameters of the non-growing region between 5-7 day old plants could be found whereas in 4 day old plants both tensile stiffness and ultimate tensile stress were significantly lower than in the older plants. Furthermore hypocotyl diameters and densities remain almost the same for 5, 6 and 7 day old seedlings. Naturally, hypocotyl lengths increase with age. The evaluation whether the choice-age or length-influences the mechanical properties showed that both are equally applicable sampling parameters. Additionally, our detailed study allows for the estimation of biological variability, connections between mechanics and hypocotyl age could be established and complement the knowledge on biochemistry and genetics affecting primary plant cell wall growth. The application of two different micromechanical devices for testing living Arabidopsis hypocotyls allows for emphasizing and discussing experimental limitations and for presenting a wide range of possibilities to address current and future

Methylphenidate and the response to growth hormone treatment in short children born small for gestational age.

PubMed

Renes, Judith S; de Ridder, Maria A J; Breukhoven, Petra E; Lem, Annemieke J; Hokken-Koelega, Anita C S

2012-01-01

Growth hormone (GH) treatment has become a frequently applied growth promoting therapy in short children born small for gestational age (SGA). Children born SGA have a higher risk of developing attention deficit hyperactivity disorder (ADHD). Treatment of ADHD with methylphenidate (MP) has greatly increased in recent years, therefore more children are being treated with GH and MP simultaneously. Some studies have found an association between MP treatment and growth deceleration, but data are contradictory. To explore the effects of MP treatment on growth in GH-treated short SGA children Anthropometric measurements were performed in 78 GH-treated short SGA children (mean age 10.6 yr), 39 of whom were also treated with MP (SGA-GH/MP). The SGA-GH/MP group was compared to 39 SGA-GH treated subjects. They were matched for sex, age and height at start of GH, height SDS at start of MP treatment and target height SDS. Serum insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) levels were yearly determined. Growth, serum IGF-I and IGFBP-3 levels during the first three years of treatment were analyzed using repeated measures regression analysis. The SGA-GH/MP group had a lower height gain during the first 3 years than the SGA-GH subjects, only significant between 6 and 12 months of MP treatment. After 3 years of MP treatment, the height gain was 0.2 SDS (± 0.1 SD) lower in the SGA-GH/MP group (P = 0.17). Adult height was not significantly different between the SGA-GH/MP and SGA-GH group (-1.9 SDS and -1.9 SDS respectively, P = 0.46). Moreover, during the first 3 years of MP treatment IGF-I and IGFBP-3 measurements were similar in both groups. MP has some negative effect on growth during the first years in short SGA children treated with GH, but adult height is not affected.

Structural Integrity and Aging-Related Issues of Helicopters

DTIC Science & Technology

2000-10-01

inherently damage lolerant , any damage- inspection in critical locations where tests have indicated tolerant features in airframe design only enhances...required, so European Rotorcraft Forum. Marseilles, France, 15- that helicopters are equipped with such features as fly- 17 September 1998 . by-wire and...fatigue Evaluation of structural integrity issues of aging helicopters. The Structure," 29 April, 1998 . extended safe-life approach encompasses the best

Independent effects and interactions of stand diameter, tree diameter, crown class, and age on tree growth in mixed-species, even-aged hardwood stands

Treesearch

D.A. Marquis

1991-01-01

Many studies have shown that initial tree diameter is closely correlated with subsequent tree growth. But initial tree diameter is actually a confounded variable, incorporating both competitive position (crown class) and age.

The Plantation Conversion Demonstration at the Crossett Experimental Forest--Implications For Converting Stands From Even-Aged to Uneven-Aged Structure

Treesearch

James M. Guldin; Robert M. Farrar

2002-01-01

In the absence of replicated studies, we used a case study demonstration to illustrate converting a 26-year-old even-aged loblolly pine (Pinus taeda L.) plantation to uneven-aged structure. Unreplicated treatments included maintaining even-aged structure through low thinning (thinning from below) to a residual basal area of 80 square feet per acre,...

Intrauterine growth restriction is associated with structural alterations in human umbilical cord and decreased nitric oxide-induced relaxation of umbilical vein.

PubMed

Peyter, A-C; Delhaes, F; Baud, D; Vial, Y; Diaceri, G; Menétrey, S; Hohlfeld, P; Tolsa, J-F

2014-11-01

Intrauterine growth restriction (IUGR) affects ∼8% of all pregnancies and is associated with major perinatal mortality and morbidity, and with an increased risk to develop cardiovascular diseases in adulthood. Despite identification of several risk factors, the mechanisms implicated in the development of IUGR remain poorly understood. In case of placental insufficiency, reduced delivery of oxygen and/or nutrients to the fetus could be associated with alterations in the umbilical circulation, contributing further to the impairment of maternal-fetal exchanges. We compared the structural and functional properties of umbilical cords from growth-restricted and appropriate for gestational age (AGA) term newborns, with particular attention to the umbilical vein (UV). Human umbilical cords were collected at delivery. Morphological changes were investigated by histomorphometry, and UV's reactivity by pharmacological studies. Growth-restricted newborns displayed significantly lower growth parameters, placental weight and umbilical cord diameter than AGA controls. Total cross-section and smooth muscle areas were significantly smaller in UV of growth-restricted neonates than in controls. Maximal vasoconstriction achieved in isolated UV was lower in growth-restricted boys than in controls, whereas nitric oxide-induced relaxation was significantly reduced in UV of growth-restricted girls compared to controls. IUGR is associated with structural alterations of the UV in both genders, and with a decreased nitric oxide-induced relaxation in UV of newborn girls, whereas boys display impaired vasoconstriction. Further investigations will allow to better understand the regulation of umbilical circulation in growth-restricted neonates, which could contribute to devise potential novel therapeutic strategies to prevent or limit the development of IUGR. Copyright © 2014 Elsevier Ltd. All rights reserved.

A tropical freshwater wetland: I Structure, growth, and regeneration

Treesearch

James A. Allen; Ken W. Krauss; Katherine C. Ewel; Bobby D Keeland; Erick E. Waguk

2005-01-01

Forested wetlands dominated by (Terminalia carolinensis) are endemic to Micronesia but common only on the island of Kosrae, Federated States of Micronesia. On Kosrae, these forests occur on Nansepsep, Inkosr, and Sonahnpil soil types, which differ in degree of flooding and soil saturation. We compared forest structure, growth, nutrition, and...

Nucleotide supplementation and the growth of term small for gestational age infants.

PubMed Central

Cosgrove, M.; Davies, D. P.; Jenkins, H. R.

1996-01-01

A double blind randomised controlled trial in small for gestational age (SGA) infants, whose intestinal mucosa was shown to be functionally impaired as a result of intrauterine undernutrition, was carried out to investigate the hypothesis that nucleotide supplementation of a milk formula could improve catchup growth. Anthropometric data were collected on 74 infants, 39 randomly allocated to the nucleotide supplemented group (group N) and 35 to a standard formula group (group S). From study entry to 2 months of age, infants in group N had significantly higher mean rates of weight gain (106.3 compared with 94.7 g/kg baseline weight/week) and length gain (21.8 v 19.7 mm/m baseline length/week). Over the whole six months for which the trial formula was provided group N had significantly higher mean rates of gain of weight (80.1 compared with 71.8 g/kg baseline weight/week), length (16.2 compared with 15.0 mm/m baseline length/week), and head circumference (11.8 compared with 10.8 mm/m baseline head circumference/week). Catchup growth in SGA infants is therefore improved by nucleotide supplementation of infant formula. PMID:8777659

Age Determination by Back Length for African Savanna Elephants: Extending Age Assessment Techniques for Aerial-Based Surveys

PubMed Central

Trimble, Morgan J.; van Aarde, Rudi J.; Ferreira, Sam M.; Nørgaard, Camilla F.; Fourie, Johan; Lee, Phyllis C.; Moss, Cynthia J.

2011-01-01

Determining the age of individuals in a population can lead to a better understanding of population dynamics through age structure analysis and estimation of age-specific fecundity and survival rates. Shoulder height has been used to accurately assign age to free-ranging African savanna elephants. However, back length may provide an analog measurable in aerial-based surveys. We assessed the relationship between back length and age for known-age elephants in Amboseli National Park, Kenya, and Addo Elephant National Park, South Africa. We also compared age- and sex-specific back lengths between these populations and compared adult female back lengths across 11 widely dispersed populations in five African countries. Sex-specific Von Bertalanffy growth curves provided a good fit to the back length data of known-age individuals. Based on back length, accurate ages could be assigned relatively precisely for females up to 23 years of age and males up to 17. The female back length curve allowed more precise age assignment to older females than the curve for shoulder height does, probably because of divergence between the respective growth curves. However, this did not appear to be the case for males, but the sample of known-age males was limited to ≤27 years. Age- and sex-specific back lengths were similar in Amboseli National Park and Addo Elephant National Park. Furthermore, while adult female back lengths in the three Zambian populations were generally shorter than in other populations, back lengths in the remaining eight populations did not differ significantly, in support of claims that growth patterns of African savanna elephants are similar over wide geographic regions. Thus, the growth curves presented here should allow researchers to use aerial-based surveys to assign ages to elephants with greater precision than previously possible and, therefore, to estimate population variables. PMID:22028925

Isotropic and Anisotropic Growth of Metal-Organic Framework (MOF) on MOF: Logical Inference on MOF Structure Based on Growth Behavior and Morphological Feature.

PubMed

Choi, Sora; Kim, Taeho; Ji, Hoyeon; Lee, Hee Jung; Oh, Moonhyun

2016-11-02

The growth of one metal-organic framework (MOF) on another MOF for constructing a heterocompositional hybrid MOF is an interesting research topic because of the curiosity regarding the occurrence of this phenomenon and the value of hybrid MOFs as multifunctional materials or routes for fine-tuning MOF properties. In particular, the anisotropic growth of MOF on MOF is fascinating for the development of MOFs possessing atypical shapes and heterostructures or abnormal properties. Herein, we clarify the understanding of growth behavior of a secondary MOF on an initial MOF template, such as isotropic or anisotropic ways associated with their cell parameters. The isotropic growth of MIL-68-Br on the MIL-68 template results in the formation of core-shell-type MIL-68@MIL-68-Br. However, the unique anisotropic growth of a secondary MOF (MOF-NDC) on the MIL-68 template results in semitubular particles, and structural features of this unknown secondary MOF are successfully speculated for the first time on the basis of its unique growth behavior and morphological characteristics. Finally, the validation of this structural speculation is verified by the powder X-ray diffraction and the selected area electron diffraction studies. The results suggests that the growth behavior and morphological features of MOFs should be considered to be important factors for understanding the MOFs' structures.

Post-term growth and cognitive development at 5 years of age in preterm children: Evidence from a prospective population-based cohort.

PubMed

Simon, Laure; Nusinovici, Simon; Flamant, Cyril; Cariou, Bertrand; Rouger, Valérie; Gascoin, Géraldine; Darmaun, Dominique; Rozé, Jean-Christophe; Hanf, Matthieu

2017-01-01

While the effects of growth from birth to expected term on the subsequent development of preterm children has attracted plentiful attention, less is known about the effects of post-term growth. We aimed to delineate distinct patterns of post-term growth and to determine their association with the cognitive development of preterm children. Data from a prospective population-based cohort of 3,850 surviving infants born at less than 35 weeks of gestational age were used. Growth was assessed as the Body Mass Index (BMI) Z-scores at 3, 9, 18, 24, 36, 48, and 60 months. Cognitive development at five years of age was evaluated by the Global School Adaptation score (GSA). Latent class analysis was implemented to identify distinct growth patterns and logistic regressions based on propensity matching were used to evaluate the relationship between identified growth trajectories and cognitive development. Four patterns of post-term growth were identified: a normal group with a Z-score consistently around zero during childhood (n = 2,469; 64%); a group with an early rapid rise in the BMI Z-score, but only up to 2 years of age (n = 195; 5%); a group with a slow yet steady rise in the BMI Z-score during childhood (n = 510; 13%); and a group with a negative Z-score growth until 3 years of age (n = 676; 18%). The group with a slow yet steady rise in the BMI Z-score was significantly associated with low GSA scores. Our findings indicate heterogeneous post-term growth of preterm children, with potential for association with their cognitive development.

The growth of IQ among Estonian schoolchildren from ages 7 to 19.

PubMed

Pullmann, Helle; Allik, Jüri; Lynn, Richard

2004-11-01

The Standard Progressive Matrices test was standardized in Estonia on a representative sample of 4874 schoolchildren aged from 7 to 19 years. When the IQ of Estonian children was expressed in relation to British and Icelandic norms, both demonstrated a similar sigmoid relationship. The youngest Estonian group scored higher than the British and Icelandic norms: after first grade, the score fell below 100 and remained lower until age 12, and after that age it increased above the mean level of these two comparison countries. The difference between the junior school children and the secondary school children may be due to schooling, sampling error or different trajectories of intellectual maturation in different populations. Systematic differences in the growth pattern suggest that the development of intellectual capacities proceeds at different rates and the maturation process can take longer in some populations than in others.

Effect of castration at 10 months of age on growth physiology and behavior of male feral beef cattle.

PubMed

Álvarez-Rodríguez, Javier; Albertí, Pere; Ripoll, Guillermo; Blasco, Isabel; Sanz, Albina

2017-07-01

This study compared the growth performance, plasma testosterone and cortisol levels around castration at 10 months of age, and plasma insulin-like growth factor (IGF)-I concentration and flight speed, in intact bulls and steers from 10 to 21 months of age in a feral Spanish breed. Fourteen bulls (366.5 ± 48.5 kg live weight) were assigned at random to one of two treatments: surgically castrated (steers) or intact (bulls), and submitted to an identical fattening period. Steers reared until heavy live weights (21 months of age) grew slowly and had lower plasma IGF-I concentrations than intact bulls. These differences were mainly highlighted the month after surgery (11 months of age) and the last part of the fattening period (from 19 to 21 months of age). After surgical castration (11 and 12 months of age), steers showed a tendency to display greater flight speed values than intact bulls but baseline plasma cortisol concentration did not differ between groups at this time. At the end, steers and bulls reached nearly similar temperament, as flight speed did not differ between them. The results confirm the role of IGF-I as a key anabolic hormone in male beef cattle and thus it may reflect growth differences due to altered sex steroids production. © 2016 Japanese Society of Animal Science.

Some genetic problems in physical growth and development. A longitudinal study on children aged 0--7 years.

PubMed

Chrzastek-Spruch, H M

1977-01-01

Aiming at determining the influence of some genetic factors on growth and development, a longitudinal study of 180 children (90 M and 90 F) from the city of Lublin was carried out, with periodical medical examinations and anthropometric measurements from birth to 7 years of age. The parents of each child were also examined. The correlation coefficients between parents and children show that, as regards height, the greatest similarity occurs between mothers and daughters, and a lesser one between fathers and sons. As regards weight, sons are more similar to fathers than daughters to mothers. The relationship between the growth and development of children and the mating type of parents, parental age, and birth order, was also investigated. In negative assortative mating, the children are taller than the children of middle-height parents from positive assortative mating couples. Children (especially daughters) of tall mothers and short fathers grow taller than children of tall fathers and short mothers. Finally, the dependence of growth on parental age and birth order was analysed and the conclusions reached were quite interesting.

Aging of Johari-Goldstein Relaxation in Structural Glasses

NASA Astrophysics Data System (ADS)

Yardimci, Hasan; Leheny, Robert L.

2006-03-01

Using frequency-dependent dielectric susceptibility measurements we characterize the aging in two supercooled liquids, sorbitol and xylitol, below their calorimetric glass transition temperatures, Tg. In addition to the alpha relaxation that tracks the structural dynamics, the susceptibilities of both liquids possess a secondary Johari-Goldstein relaxation at higher frequencies. Following a quench below Tg, the susceptibility slowly approaches equilibrium behavior. For both liquids, features of the Johari-Goldstein relaxation display a dependence on the time since the quench, or aging time, that is very similar to the age dependence of the alpha peak. However, one can not assign a single fictive temperature to both the alpha and Johari-Goldstein relaxations. For example, the peak frequency of the Johari-Goldstein relaxation remains constant during aging for sorbitol while it increases with age for xylitol, inconsistent with a decreasing fictive temperature. This behavior contrasts with that of the high frequency tail of the alpha peak whose shape and position track the aging of the main part of the peak.

Feeding preterm infants after hospital discharge: growth and development at 18 months of age.

PubMed

Cooke, R J; Embleton, N D; Griffin, I J; Wells, J C; McCormick, K P

2001-05-01

We have shown that preterm infants fed a preterm formula grow better than those fed a standard term infant formula after hospital discharge. The purpose of this follow-up study was to determine whether improved early growth was associated with later growth and development. Preterm infants (< or =1750 g birth weight, < or =34 wk gestation) were randomized to be fed either a preterm infant formula (discharge to 6 mo corrected age), or a term formula (discharge to 6 mo), or the preterm (discharge to term) and the term formula (term to 6 mo). Anthropometry was performed at 12 wk and 6, 12, and 18 mo. Mental and psychomotor development were assessed using the Bayley Scales of Infant Development II at 18 mo. Differences in growth observed at 12 wk were maintained at 18 mo. At 18 mo, boys fed the preterm formula were 1.0 kg heavier, 2 cm longer, and had a 1.0 cm greater occipitofrontal circumference than boys fed the term formula. Boys fed the preterm formula were also 600 g heavier and 2 cm longer than girls fed the preterm formula. However, no differences were noted in MDI or PDI between boys fed the preterm formula and boys fed the term formula or between the boys fed preterm formula and girls fed the preterm formula. Overall, boys had significantly lower MDI than girls (mean difference, 6.0; p < 0.01), primarily reflecting lower scores in boys fed the term formula. Thus, early diet has long-term effects on growth but not development at 18 mo of age. Sex remains an important confounding variable when assessing growth and developmental outcome in these high-risk infants.

A size-structured model of bacterial growth and reproduction.

PubMed

Ellermeyer, S F; Pilyugin, S S

2012-01-01

We consider a size-structured bacterial population model in which the rate of cell growth is both size- and time-dependent and the average per capita reproduction rate is specified as a model parameter. It is shown that the model admits classical solutions. The population-level and distribution-level behaviours of these solutions are then determined in terms of the model parameters. The distribution-level behaviour is found to be different from that found in similar models of bacterial population dynamics. Rather than convergence to a stable size distribution, we find that size distributions repeat in cycles. This phenomenon is observed in similar models only under special assumptions on the functional form of the size-dependent growth rate factor. Our main results are illustrated with examples, and we also provide an introductory study of the bacterial growth in a chemostat within the framework of our model.

Trends and predicted trends in presentations of older people to Australian emergency departments: effects of demand growth, population aging and climate change.

PubMed

Burkett, Ellen; Martin-Khan, Melinda G; Scott, Justin; Samanta, Mayukh; Gray, Leonard C

2017-07-01

Objectives The aim of the present study was to describe trends in and age and gender distributions of presentations of older people to Australian emergency departments (EDs) from July 2006 to June 2011, and to develop ED utilisation projections to 2050. Methods A retrospective analysis of data collected in the National Non-admitted Patient Emergency Department Care Database was undertaken to assess trends in ED presentations. Three standard Australian Bureau of Statistics population growth models, with and without adjustment for current trends in ED presentation growth and effects of climate change, were examined with projections of ED presentations across three age groups (0-64, 65-84 and ≥85 years) to 2050. Results From 2006-07 to 2010-11, ED presentations increased by 12.63%, whereas the Australian population over this time increased by only 7.26%. Rates of presentation per head of population were greatest among those aged ≥85 years. Projections of ED presentations to 2050 revealed that overall ED presentations are forecast to increase markedly, with the rate of increase being most marked for older people. Conclusion Growth in Australian ED presentations from 2006-07 to 2010-11 was greater than that expected from population growth alone. The predicted changes in demand for ED care will only be able to be optimally managed if Australian health policy, ED funding instruments and ED models of care are adjusted to take into account the specific care and resource needs of older people. What is known about the topic? Rapid population aging is anticipated over coming decades. International studies and specific local-level Australian studies have demonstrated significant growth in ED presentations. There have been no prior national-level Australian studies of ED presentation trends by age group. What does this paper add? The present study examined national ED presentation trends from July 2006 to June 2011, with specific emphasis on trends in presentation by age