Science.gov

Sample records for age structure growth

  1. Changes in Age Structure and Rural Community Growth.

    ERIC Educational Resources Information Center

    McGranahan, David A.

    1985-01-01

    Whatever migration patterns evolve, changes in the age structure mean that rural communities in general can expect fairly stable elementary school population, reduced high school population, slower growth in new business and employment, and continued increase in the elderly population. (JHZ)

  2. Socio-Demographic Determinants of Economic Growth: Age-Structure, Preindustrial Heritage and Sociolinguistic Integration

    ERIC Educational Resources Information Center

    Crenshaw, Edward; Robison, Kristopher

    2010-01-01

    This study establishes a socio-demographic theory of international development derived from selected classical and contemporary sociological theories. Four hypotheses are tested: (1. population growth's effect on development depends on age-structure; (2. historic population density (used here as an indicator of preindustrial social complexity)…

  3. Contaminant effects on growth, age-structure, and reproduction, of Mytilus edulis from Puget Sound, Washington

    SciTech Connect

    Casillas, E.; Kardong, K.; Kagley, A.; Snider, R.G.; Stein, J.E.

    1994-12-31

    Age-length relationships, age structure, and reproductive status (fecundity, egg size) of Mytilus edulis from six sites in central Puget Sound and one site in the relatively pristine area of northern Puget Sound were measured. Mussels from urban-associated sites (areas with elevated sediment concentrations of PAHs, PCBs, and toxic and essential metals) exhibited high tissue burdens of these contaminants. Age length relationships, fitted to the von Bertalanffy equation, showed that the growth of mussels from urban-associated areas was similar, but was lower than in mussels from minimally-contaminated environments. Comparison of mussel population age-structure showed that at urban sites, mussels of comparable size were consistently older than mussels from minimally contaminated areas and the mean age of urban populations was higher than that of rural populations. In mussels from urban sites, gonad mass was lower while number of oocytes/g gonad was similar compared to mussels from minimally-contaminated areas of Puget Sound. Thus, in mussels from urban sites fecundity was reduced compared to mussels of comparable age from reference sites. The findings support the hypothesis that mussels from the urban areas exhibit impaired growth, altered population age-structure, and reproductive impairment as a result of accumulation of chemical contaminants.

  4. Structural basis of growth-related gain and age-related loss of bone strength

    PubMed Central

    2008-01-01

    If bone strength was the only requirement of skeleton, it could be achieved with bulk, but bone must also be light. During growth, bone modelling and remodelling optimize strength, by depositing bone where it is needed, and minimize mass, by removing it from where it is not. The population variance in bone traits is established before puberty and the position of an individual's bone size and mass tracks in the percentile of origin. Larger cross-sections have a comparably larger marrow cavity, which results in a lower volumetric BMD (vBMD), thereby avoiding bulk. Excavation of a marrow cavity thus minimizes mass and shifts the cortex radially, increasing rigidity. Smaller cross-sections are assembled by excavating a smaller marrow cavity leaving a relatively thicker cortex producing a higher vBMD, avoiding the fragility of slenderness. Variation in cellular activity around the periosteal and endocortical envelopes fashions the diverse shapes of adjacent cross-sections. Advancing age is associated with a decline in periosteal bone formation, a decline in the volume of bone formed by each basic multicellular unit (BMU), continued resorption by each BMU, and high remodelling after menopause. Bone loss in young adulthood has modest structural and biomechanical consequences because the negative BMU balance is driven by reduced bone formation, remodelling is slow and periosteal apposition continues shifting the thinned cortex radially. But after the menopause, increased remodelling, worsening negative BMU balance and a decline in periosteal apposition accelerate cortical thinning and porosity, trabecular thinning and loss of connectivity. Interstitial bone, unexposed to surface remodelling becomes more densely mineralized, has few osteocytes and greater collagen cross-linking, and accumulates microdamage. These changes produce the material and structural abnormalities responsible for bone fragility. PMID:18556646

  5. Anomalous Growth of Aging Populations

    NASA Astrophysics Data System (ADS)

    Grebenkov, Denis S.

    2016-04-01

    We consider a discrete-time population dynamics with age-dependent structure. At every time step, one of the alive individuals from the population is chosen randomly and removed with probability q_k depending on its age, whereas a new individual of age 1 is born with probability r. The model can also describe a single queue in which the service order is random while the service efficiency depends on a customer's "age" in the queue. We propose a mean field approximation to investigate the long-time asymptotic behavior of the mean population size. The age dependence is shown to lead to anomalous power-law growth of the population at the critical regime. The scaling exponent is determined by the asymptotic behavior of the probabilities q_k at large k. The mean field approximation is validated by Monte Carlo simulations.

  6. Effects of chemical contaminants on growth, age-structure, and reproduction of Mytilus edulis complex from Puget sound, Washington.

    PubMed

    Kagley, Anna N; Kardong, Kyle E; Snider, Robert G; Casillas, Edmundo

    2014-07-01

    Bivalves are used as sentinel species to detect chemical contaminants in the marine environment, but biological effects on indigenous populations that result from chemical exposure are largely unknown. We assessed age-weight, length-weight relationships, age structure, and reproductive status (i.e. fecundity, egg size) of the blue mussel Mytilus edulis complex from six sites in central Puget Sound, Washington, and one site in the relatively pristine area of northern Puget Sound. Results of this study suggest that mussels from urban areas of Puget Sound exhibit a lower growth rate, altered population age-structure, and potential reproductive impairment as a result of exposure to chemical contaminants. These findings support the use of mussels as sentinel species to assess the biological effects of contaminants on invertebrate populations. PMID:24852611

  7. Individual fitness and phenotypic selection in age-structured populations with constant growth rates

    PubMed Central

    Moorad, Jacob A.

    2013-01-01

    Powerful multiple regression-based approaches are commonly used to measure the strength of phenotypic selection, which is the statistical association between individual fitness and trait values. Age structure and overlapping generations complicate determinations of individual fitness, contributing to the popularity of alternative methods for measuring natural selection that do not depend upon such measures. The application of regression-based techniques for measuring selection in these situations requires a demographically appropriate, conceptually sound, and observable measure of individual fitness. It has been suggested that Fisher’s reproductive value applied to an individual at its birth is such a definition. Here I offer support for this assertion by showing that multiple regression applied to this measure and vital rates (age-specific survival and fertility rates) yields the same selection gradients for vital rates as those inferred from Hamilton’s classical results. I discuss how multiple regressions, applied to individual reproductive value at birth, can be used efficiently to estimate measures of phenotypic selection that are problematic for sensitivity analyses. These include nonlinear selection, components of the opportunity for selection, and multi-level selection. PMID:24933826

  8. Growth and Age-Related Abnormalities in Cortical Structure and Fracture Risk.

    PubMed

    Seeman, Ego

    2015-12-01

    Vertebral fractures and trabecular bone loss have dominated thinking and research into the pathogenesis and the structural basis of bone fragility during the last 70 years. However, 80% of all fractures are non-vertebral and occur at regions assembled using large amounts of cortical bone; only 20% of fractures are vertebral. Moreover, ~80% of the skeleton is cortical and ~70% of all bone loss is cortical even though trabecular bone is lost more rapidly than cortical bone. Bone is lost because remodelling becomes unbalanced after midlife. Most cortical bone loss occurs by intracortical, not endocortical remodelling. Each remodelling event removes more bone than deposited enlarging existing canals which eventually coalesce eroding and thinning the cortex from 'within.' Thus, there is a need to study the decay of cortical as well as trabecular bone, and to develop drugs that restore the strength of both types of bone. It is now possible to accurately quantify cortical porosity and trabecular decay in vivo. The challenges still to be met are to determine whether measurement of porosity identifies persons at risk for fracture, whether this approach is compliments information obtained using bone densitometry, and whether changes in cortical porosity and other microstructural traits have the sensitivity to serve as surrogates of treatment success or failure. PMID:26394727

  9. Growth and Age-Related Abnormalities in Cortical Structure and Fracture Risk

    PubMed Central

    2015-01-01

    Vertebral fractures and trabecular bone loss have dominated thinking and research into the pathogenesis and the structural basis of bone fragility during the last 70 years. However, 80% of all fractures are non-vertebral and occur at regions assembled using large amounts of cortical bone; only 20% of fractures are vertebral. Moreover, ~80% of the skeleton is cortical and ~70% of all bone loss is cortical even though trabecular bone is lost more rapidly than cortical bone. Bone is lost because remodelling becomes unbalanced after midlife. Most cortical bone loss occurs by intracortical, not endocortical remodelling. Each remodelling event removes more bone than deposited enlarging existing canals which eventually coalesce eroding and thinning the cortex from 'within.' Thus, there is a need to study the decay of cortical as well as trabecular bone, and to develop drugs that restore the strength of both types of bone. It is now possible to accurately quantify cortical porosity and trabecular decay in vivo. The challenges still to be met are to determine whether measurement of porosity identifies persons at risk for fracture, whether this approach is compliments information obtained using bone densitometry, and whether changes in cortical porosity and other microstructural traits have the sensitivity to serve as surrogates of treatment success or failure. PMID:26394727

  10. 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.

  11. Growth, ageing and scaling laws of coronary arterial trees.

    PubMed

    Chen, Xi; Niu, Pei; Niu, Xiaolong; Shen, Wenzeng; Duan, Fei; Ding, Liang; Wei, Xiliang; Gong, Yanjun; Huo, Yong; Kassab, Ghassan S; Tan, Wenchang; Huo, Yunlong

    2015-12-01

    Despite the well-known design principles of vascular systems, it is unclear whether the vascular arterial tree obeys some scaling constraints during normal growth and ageing in a given species. Based on the micro-computed tomography measurements of coronary arterial trees in mice at different ages (one week to more than eight months), we show a constant exponent of 3/4, but age-dependent scaling coefficients in a length-volume scaling law (Lc=K(length-volume) · Vc³/⁴; Lc is the crown length, Vc is the crown volume, K(length-volume) is the age-dependent scaling coefficient) during normal growth and ageing. The constant 3/4 exponent represents the self-similar fractal-like branching pattern (i.e. basic mechanism to regulate the development of vascular trees within a species), whereas the age-dependent scaling coefficients characterize the structural growth or resorption of vascular trees during normal growth or ageing, respectively. This study enhances the understanding of age-associated changes in vascular structure and function. PMID:26701881

  12. Structural aging program status report

    SciTech Connect

    Naus, D.J.; Oland, C.B.; Ellingwood, B.; Graves, H.L. III

    1994-12-31

    Research is being conducted at the Oak Ridge National Laboratory under Nuclear Regulatory Commission (USNRC) sponsorship to address aging management of safety-related concrete structures. Documentation is being prepared to provide the USNRC with potential structural safety issues and acceptance criteria for use in continued service evaluations of nuclear power plants. Program accomplishments have included development of the Structural Materials Information Center containing data and information on the time variation of 144 material properties under the influence of pertinent environmental stressors or aging factors, performance assessments of reinforced concrete structures in several United Kingdom nuclear power facilities, evaluation of European and North American repair practices for concrete, an evaluation of factors affecting the corrosion of metals embedded in concrete, and application of the time-dependent reliability methodology to reinforced concrete flexure and shear structural elements to investigate the role of in-service inspection and repair on their probability of failure.

  13. Structural aging program status report

    SciTech Connect

    Naus, D.J.; Oland, C.B.; Ellingwood, B.

    1995-04-01

    Research is being conducted at the Oak Ridge National Laboratory (ORNL) under U.S. Nuclear Regulatory Commission (USNRC) sponsorship to address aging management of safety-related concrete structures. Documentation is being prepared to provide the USNRC with potential structural safety issues and acceptance criteria for use in continued service evaluations of nuclear power plants. Program accomplishments have included development of the Structural Materials Information Center containing data and information of the time variation of 144 material properties under the influence of pertinent environmental stressors of aging factors, performance assessments of reinforced concrete structures in several United Kingdom nuclear power facilities, evaluation of European and North American repair practices for concrete, an evaluation of factors affecting the corrosion of metals embedded in concrete, and application of the time-dependent reliability methodology to reinforced concrete flexure and shear structural elements to investigate the role of in-service inspection and repair on their probability of failure.

  14. Growth factors, aging and age-related diseases.

    PubMed

    Balasubramanian, Priya; Longo, Valter D

    2016-06-01

    Simple organisms including yeast and flies with mutations in the IGF-1 and Tor-S6K pathways are dwarfs, are highly protected from toxins, and survive up to 3 times longer. Similarly, dwarf mice with deficiencies in the growth hormone-IGF-I axis are also long lived and protected from diseases. We recently reported that humans with Growth Hormone Receptor Deficiency (GHRD) rarely develop cancer or diabetes. These findings are in agreement with the effect of defects in the Tor-S6K pathways in causing dwarfism and protection of DNA. Because protein restriction reduces both GHR-IGF-1 axis and Tor-S6K activity, we examined links between protein intake, disease, and mortality in over 6000 US subjects in the NHANES CDC database. Respondents aged 50-65 reporting a high protein intake displayed an increase in IGF-I levels, a 75% increased risk of overall mortality and a 3-4 fold increased risk of cancer mortality in agreement with findings in mouse experiments. These studies point to a conserved link between proteins and amino acids, GHR-IGF-1/insulin, Tor-S6k signaling, aging, and diseases. PMID:26883276

  15. Minor influence of lifelong voluntary exercise on composition, structure, and incidence of osteoarthritis in tibial articular cartilage of mice compared with major effects caused by growth, maturation, and aging.

    PubMed

    Närhi, Tommi; Siitonen, Ulrika; Lehto, Lauri J; Hyttinen, Mika M; Arokoski, Jari P A; Brama, Pieter A; Jurvelin, Jukka S; Helminen, Heikki J; Julkunen, Petro

    2011-10-01

    We investigated the effects of lifelong voluntary exercise on articular cartilage of mice. At the age of 4 weeks C57BL mice (n = 152) were divided into two groups, with one group serving as a sedentary control whereas the other was allowed free access to a running wheel from the age of 1 month onward. Mice were euthanized at four different time points (1, 2, 6, and 18 months of age). Articular cartilage samples were gathered from the load-bearing area of the tibial medial plateaus, and osteoarthritis was graded. Additionally, the proteoglycan content distribution was assessed using digital densitometry, collagen fibril orientation, and parallelism with polarized light microscopy, and collagen content using Fourier transform infrared imaging spectroscopy. The incidence of osteoarthritis increased with aging, but exercise had no effect on this trend. Furthermore, the structure and composition revealed significant growth, maturation, and age-dependent properties. Exercise exerted a minor effect on collagen fibril orientation in the superficial zone. Fibril orientation at 2 months of age was more perpendicular to surface (p < 0.05) in controls compared with runners, whereas the situation was reversed at the age of 18 months (p < 0.05). The collagen content of the superficial zone was higher (p < 0.01) at the age of 18 months in controls compared with runners but the proteoglycan content did not display any exercise-dependent changes. In conclusion, growth, maturation, and aging exerted a clear effect on integrity, structure, and composition of medial tibial plateau articular cartilage in mice, whereas lifelong voluntary exercise had only a minor effect on collagen architecture and content. PMID:21405978

  16. 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

  17. 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. PMID:15347508

  18. 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.

  19. Growth hormone, insulin-like growth factor-1 and the aging brain.

    PubMed

    Ashpole, Nicole M; Sanders, Jessica E; Hodges, Erik L; Yan, Han; Sonntag, William E

    2015-08-01

    Growth hormone (GH) and insulin-like growth factor (IGF)-1 regulate the development and function of cells throughout the body. Several clinical diseases that result in a decline in physical and mental functions are marked by mutations that disrupt GH or IGF-1 signaling. During the lifespan there is a robust decrease in both GH and IGF-1. Because GH and IGF-1 are master regulators of cellular function, impaired GH and IGF-1 signaling in aging/disease states leads to significant alterations in tissue structure and function, especially within the brain. This review is intended to highlight the effects of the GH and IGF-1 on neuronal structure, function, and plasticity. Furthermore, we address several potential mechanisms through which the age-related reductions in GH and IGF-1 affect cognition. Together, the studies reviewed here highlight the importance of maintaining GH and IGF-1 signaling in order to sustain proper brain function throughout the lifespan. PMID:25300732

  20. 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.

  1. Job Structure and Age Satisfaction

    ERIC Educational Resources Information Center

    Phillips, James S.; And Others

    1978-01-01

    From research findings on job design and redesign, the authors conclude that all individuals may not approve job enrichment programs which may actually decrease job satisfaction. Although job satisfaction may increase with age, individual differences and other variables make research results inconclusive. (MF)

  2. Funding growth in an age of austerity.

    PubMed

    Hamel, Gary; Getz, Gary

    2004-01-01

    Everyone knows that corporate growth--true growth, not just agglomeration--springs from innovation. And the common wisdom is that companies must spend lavishly on R&D if they are to innovate at all. But in these fiscally cautious times, where every line item of every budget in every company is under intense scrutiny, many organizations are doing just the opposite. They tighten their belts, subject nascent product-development programs to rigorous screening, and train R&D staffers to think in business terms so the researchers will be better able to decide whether an idea for a product or service is worth pursuing in the first place. Such efficiency measures are commendable, say authors Gary Hamel and Gary Getz. But frugality is not a growth strategy, they point out, and, in truth, there is very little correlation between corporate performance and the amount spent on innovation. Companies like Southwest, Cemex, and Shell Chemicals have shown that businesses don't have to spend a fortune on R&D to reap the benefits of innovation. To produce more growth per dollar invested, companies must produce more innovation per dollar invested. Hamel and Getz explain how businesses can dramatically improve their innovation yields. They offer these five imperatives: Increase the number of innovators among existing employees (whatever their job titles) by involving them in innovation processes and events. Focus on developing truly radical ideas--ones that change customers' expectations and behaviors and industry economics--not just incremental ideas. Look for innovation sources outside the organization, as well as inside. Increase the learning from small, low-risk experiments. And commit to long-term, consistent development efforts. PMID:15241954

  3. Structural aging program status report

    SciTech Connect

    Naus, D.J.; Oland, C.B.; Ellingwood, B.

    1994-10-01

    Reinforced concrete structures play a vital role in the safe operation of all light-water reactor plants. In general, the performance of these structures has been satisfactory. However, there have been several instances where the capability of these structures to meet future functional and performance requirements has been challenged due to problems arising from either improper material selection, construction and design deficiencies, or environmental effects. Examples of some of the potentially more serious incidents include post-tensioning anchor head failures, leaching of concrete in tendon galleries, voids under vertical tendon bearing plates, containment dome delaminations, corrosion of steel tendons and rebars, water intrusion through basement cracks, and leakage of corrosion inhibitor from tendon sheaths. Such incidents indicate that there is a need for improved surveillance, inspection and testing, and maintenance to enhance the technical bases for assurance of continued safe operation of nuclear power plants both during the initial licensing period as well as throughout any continued service period.

  4. Orthographic Word Knowledge Growth in School-Age Children

    ERIC Educational Resources Information Center

    Wagovich, Stacy A.; Pak, Youngju; Miller, Margaret D.

    2012-01-01

    Purpose: Natural reading experiences provide an opportunity for the development of orthographic word knowledge as well as other forms of partial word knowledge. The purpose of this study was to compare the orthographic word knowledge growth of school-age children with relatively low language skills (LL group) to that of age- and gender-matched…

  5. 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

  6. 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.

  7. Do otolith increments allow correct inferences about age and growth of coral reef fishes?

    NASA Astrophysics Data System (ADS)

    Booth, D. J.

    2014-03-01

    Otolith increment structure is widely used to estimate age and growth of marine fishes. Here, I test the accuracy of the long-term otolith increment analysis of the lemon damselfish Pomacentrus moluccensis to describe age and growth characteristics. I compare the number of putative annual otolith increments (as a proxy for actual age) and widths of these increments (as proxies for somatic growth) with actual tagged fish-length data, based on a 6-year dataset, the longest time course for a coral reef fish. Estimated age from otoliths corresponded closely with actual age in all cases, confirming annual increment formation. However, otolith increment widths were poor proxies for actual growth in length [linear regression r 2 = 0.44-0.90, n = 6 fish] and were clearly of limited value in estimating annual growth. Up to 60 % of the annual growth variation was missed using otolith increments, suggesting the long-term back calculations of otolith growth characteristics of reef fish populations should be interpreted with caution.

  8. Radiocarbon Based Ages and Growth Rates: Hawaiian Deep Sea Corals

    SciTech Connect

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

    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 specimens 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.

  9. Density, ages, and growth rates in old-growth and young-growth forests in coastal Oregon

    USGS Publications Warehouse

    Tappeiner, J. C., II; Huffman, D.; Spies, T.; Bailey, John D.

    1997-01-01

    We studied the ages and diameter growth rates of trees in former Douglas-fir (Pseudotsuga menziesii (Mirb.)Franco) old-growth stands on 10 sites and compared them with young-growth stands (50-70 years old, regenerated after timber harvest) in the Coast Range of western Oregon. The diameters and diameter growth rates for the first 100 years of trees in the old-growth stands were significantly greater than those in the young-growth stands. Growth rates in the old stands were comparable with those from long-term studies of young stands in which density is about 100-120 trees/ha; often young-growth stand density is well over 500 trees/ha. Ages of large trees in the old stands ranged from 100 to 420 years; ages in young stands varied by only about 5 to 10 years. Apparently, regeneration of old-growth stands on these sites occurred over a prolonged period, and trees grew at low density with little self-thinning; in contrast, after timber harvest, young stands may develop with high density of trees with similar ages and considerable self-thinning. The results suggest that thinning may be needed in dense young stands where the management objective is to speed development of old-growth characteristics.

  10. Age, growth and size interact with stress to determine life span and mortality.

    PubMed

    Roach, Deborah Ann

    2012-10-01

    Individuals in a large experimental field population, of the short-lived perennial species Plantago lanceolata, were followed to determine the sources of variation that influence mortality and life span. The design included multiple age groups with initially similar genetic structure, which made it possible to separate age effects from period effects and to identify the genetic component to variation in life span. During a period of stress, individuals of all ages showed parallel increases in mortality but different cohorts experienced this period of high mortality at different ages. This then influenced the distribution of life spans across cohorts. Age and size-age interactions influenced mortality during the period of stress. Smaller individuals died but only if they were old. Additionally, growth and age interacted with stress such that older individuals had negative growth and high mortality whereas younger individuals had positive growth and relatively lower mortality during stress. The results of this study show that it is not simply the environment that can have a major impact on demography in natural populations; rather, age, size and growth can interact with the environment to influence mortality and life span when the environment is stressful. PMID:22664575

  11. 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. PMID:26370639

  12. Severe Bronchopulmonary Dysplasia, Growth, Nutrition, and Adipokines at School Age

    PubMed Central

    Suursalmi, Piia; Korhonen, Päivi; Kopeli, Tarja; Nieminen, Riina; Luukkaala, Tiina; Moilanen, Eeva; Tammela, Outi

    2016-01-01

    This study evaluated nutrition and growth in relation to plasma adipokine levels in 21 very-low-birth-weight (VLBW) children with radiographic bronchopulmonary dysplasia (BPD), 19 VLBW controls, and 19 term controls with a median age of 11.3 years. We took anthropometric measurements; assessed plasma levels of adipsin, resistin, adiponectin, and leptin; and analyzed the children’s 3-day food records. Children with BPD had a smaller age-adjusted head circumference and more microcephaly but no other significant growth differences. Daily recommended nutritional intake levels were poorly met but did not differ between the groups. Leptin levels correlated positively with the body mass index standard deviation score in VLBW children. No other associations between adipokine concentrations and growth were found. There were negative correlations between leptin concentrations and fat intake, resistin levels and carbohydrate intake, and adiponectin, adipsin, and leptin levels and energy intake. PMID:27336010

  13. Postnatal growth and age estimation in Scotophilus kuhlii.

    PubMed

    Chen, Shiang-Fan; Huang, Shang-Shang; Lu, Dau-Jye; Shen, Tsung-Jen

    2016-01-01

    Adequate postnatal growth is important for young bats to develop skilled sensory and locomotor abilities, which are highly associated with their survival once independent. This study investigated the postnatal growth and development of Scotophilus kuhlii in captivity. An empirical growth curve was established, and the postnatal growth rate was quantified to derive an age-predictive equation. By further controlling the fostering conditions of twins, the differences in the development patterns between pups that received maternal care or were hand-reared were analyzed to determine whether the latter developed in the same manner as their maternally reared counterparts. Our results indicate that both forearm length and body mass increased rapidly and linearly during the first 4 weeks, after which the growth rate gradually decreased to reach a stable level. The first flight occurred at an average age of 39 days with a mean forearm length and body mass of 92.07% and 70.52% of maternal size, respectively. The developmental pattern of hand-reared pups, although similar to that of their maternally reared twin siblings, displayed a slightly faster growth rate in the 4th and 5th weeks. The heavier body mass of hand-reared pups during the pre-fledging period may cause higher wing loading, potentially influencing the flight performance and survival of the bats once independent. PMID:26600428

  14. Structural integrity of future aging airplanes

    NASA Technical Reports Server (NTRS)

    Mcguire, Jack F.; Goranson, Ulf G.

    1992-01-01

    A multitude of design considerations is involved in ensuring the structural integrity of Boeing jet transports that have common design concepts validated by extensive analyses, tests, and three decades of service. As airplanes approach their design service objectives, the incidences of fatigue and corrosion may become widespread. Continuing airworthiness of the aging jet fleet requires diligent performance from the manufacturer, the airlines, and airworthiness authorities. Aging fleet support includes timely development of supplemental structural inspection documents applicable to selected older airplanes, teardown inspections of high-time airframes retired from service, fatigue testing of older airframes, and structural surveys of more than 130 airplanes operated throughout the world. Lessons learned from these activities are incorporated in service bulletin recommendations, production line modifications, and design manual updates. An overview of traditional Boeing fleet support activities and the anticipated benefits for future generations of commercial airplanes based on the continuous design improvement process are presented.

  15. Structural integrity of future aging airplanes

    NASA Astrophysics Data System (ADS)

    McGuire, Jack F.; Goranson, Ulf G.

    1992-07-01

    A multitude of design considerations is involved in ensuring the structural integrity of Boeing jet transports that have common design concepts validated by extensive analyses, tests, and three decades of service. As airplanes approach their design service objectives, the incidences of fatigue and corrosion may become widespread. Continuing airworthiness of the aging jet fleet requires diligent performance from the manufacturer, the airlines, and airworthiness authorities. Aging fleet support includes timely development of supplemental structural inspection documents applicable to selected older airplanes, teardown inspections of high-time airframes retired from service, fatigue testing of older airframes, and structural surveys of more than 130 airplanes operated throughout the world. Lessons learned from these activities are incorporated in service bulletin recommendations, production line modifications, and design manual updates. An overview of traditional Boeing fleet support activities and the anticipated benefits for future generations of commercial airplanes based on the continuous design improvement process are presented.

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

    PubMed

    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; t0 = -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

  17. 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; t0 = –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

  18. Modeling sugarcane growth in response to age, insolation, and temperature

    SciTech Connect

    How, K.T.S.

    1986-01-01

    Modeling sugarcane growth in response to age of cane, insolation and air temperature using first-order multiple regression analysis and a nonlinear approach is investigated. Data are restricted to one variety from irrigated fields to eliminate the impact of varietal response and rainfall. Ten first-order models are investigated. The predictant is cane yield from 600 field tests. The predictors are cumulative values of insolation, maximum temperature, and minimum temperature for 3, 6, 12, and 18 months, or for each crop period derived from weather observations near the test plots. The low R-square values indicate that the selected predictor variables could not account for a substantial proportion of the variations of cane yield and the models have limited predictive values. The nonlinear model is based on known functional relationships between growth and age, growth and insolation, and growth and maximum temperature. A mathematical expression that integrates the effect of age, insolation and maximum temperature is developed. The constant terms and coefficients of the equation are determined from the requirement that the model must produce results that are reasonable when compared with observed monthly elongation data. The nonlinear model is validated and tested using another set of data.

  19. 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

  20. Accounting for age uncertainty in growth modeling, the case study of yellowfin tuna (Thunnus albacares) of the Indian Ocean.

    PubMed

    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 sagittal 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

  1. Functional and structural syntax networks in aging.

    PubMed

    Antonenko, Daria; Brauer, Jens; Meinzer, Marcus; Fengler, Anja; Kerti, Lucia; Friederici, Angela D; Flöel, Agnes

    2013-12-01

    Language abilities are known to deteriorate in aging, possibly related to decreased functional and structural connectivity within specialized brain networks. Here, we investigated syntactic ability in healthy young and older adults using a comprehensive assessment of behavioral performance, task-independent functional (FC) and structural brain connectivity (SC). Seed-based FC originating from left pars opercularis (part of Broca's area) known to support syntactic processes was assessed using resting-state functional magnetic resonance imaging, and SC using fractional anisotropy from diffusion weighted imaging, in the dorsally located superior longitudinal and the ventrally located uncinate fasciculi (SLF, UF) and forceps minor. Young compared to older adults exhibited superior syntactic performance and stronger FC within the mainly left-lateralized syntax network, which was beneficial for performance. In contrast, in older adults, FC within the mainly left-lateralized syntax network was reduced and did not correlate with performance; inter-hemispheric FC to right inferior frontal and angular gyri was detrimental for performance. In both groups, performance was positively correlated with inter-hemispheric SC. For intra-hemispheric SC, performance correlated with structural integrity of SLF in young adults and with integrity of UF in older adults. Our data show that reduced syntactic ability in older adults is associated with decreased FC within dedicated syntax networks. Moreover, young adults showed an association of syntactic ability with structural integrity of the dorsal tract, while older adults rely more on ventral fibers. In sum, our study provided novel insight into the relationship between connectivity and syntactic performance in young and older adults. In addition to elucidating age-related changes in syntax networks and their behavioral relevance, our results contribute to a better understanding of age-related changes in functional and structural brain

  2. Body growth considerations in age-specific dosimetry. Final report

    SciTech Connect

    Eckerman, K.F.

    1993-09-30

    This report describes the manner in which the age-specific dosimetric calculations of the International Commission on Radiological Protection (ICRP) addressed changes in organ size that occur with age. The approach involves an interpolation of dosimetric information derived for six reference individuals using the inverse of the total body mass as the interpolation variable. An alternative formulation is investigated that employs a functional representation of the organ mass as a function of age in conjunction with an explicit formulation of the dosimetric factors in terms of organ mass. Using an exponential-logistic growth function as suggested by Walker, this report demonstrates, through application to the dosimetry of radioiodines in the thyroid, that the alternative formulation can be formulated and implemented. Although either approach provides a workable basis for age-specific dosimetry, it is clear that the functional representation of organ growth has some attractive features. However, without question, the major difficulty is the quality and quantity of data available to address the age- and gender-specific parameters in the dosimetric formulations.

  3. Hierarchical Bayesian analysis to incorporate age uncertainty in growth curve analysis and estimates of age from length: Florida manatee (Trichechus manatus) carcasses

    USGS Publications Warehouse

    Schwarz, L.K.; Runge, M.C.

    2009-01-01

    Age estimation of individuals is often an integral part of species management research, and a number of ageestimation techniques are commonly employed. Often, the error in these techniques is not quantified or accounted for in other analyses, particularly in growth curve models used to describe physiological responses to environment and human impacts. Also, noninvasive, quick, and inexpensive methods to estimate age are needed. This research aims to provide two Bayesian methods to (i) incorporate age uncertainty into an age-length Schnute growth model and (ii) produce a method from the growth model to estimate age from length. The methods are then employed for Florida manatee (Trichechus manatus) carcasses. After quantifying the uncertainty in the aging technique (counts of ear bone growth layers), we fit age-length data to the Schnute growth model separately by sex and season. Independent prior information about population age structure and the results of the Schnute model are then combined to estimate age from length. Results describing the age-length relationship agree with our understanding of manatee biology. The new methods allow us to estimate age, with quantified uncertainty, for 98% of collected carcasses: 36% from ear bones, 62% from length.

  4. Aging and immune function: a possible role for growth hormone.

    PubMed

    Gelato, M C

    1996-01-01

    Elderly individuals have four to five times the case rate of cancer, tuberculosis and herpes zoster and six to seven times the fatality rate from pneumonia compared to young adults. This may be causally related to two changes that occur with aging, i.e. decreased growth hormone (GH)/insulin-like growth factor-1 (IGF-1) production and decreased immune function. Data from our laboratory as well as others have shown that, based on either GH secretory dynamics or IGF-1 levels, approximately 40% of adults aged 60 and older are GH deficient. In the same population of subjects, immune function decreases such that there is a decline in cell-mediated and humoral immune responsiveness. Some of these immune deficits have been shown to be reversed in humans and primates by GH and/or IGF-1 treatment. This paper will review some of these data. PMID:8742118

  5. Competing frameworks in planning for the aged in the growth corridors of Melbourne.

    PubMed

    Ozanne, Elizabeth; Biggs, Simon; Kurowski, William

    2014-01-01

    The Ageing in the Growth Corridors Project was initiated as a partnership between the University of Melbourne and the Department of Health in the Northwest Metropolitan Region of Melbourne, Australia. It involved a research team working with six project officers appointed to stimulate development in relation to an aging population in the sprawling outer metropolitan growth corridors. This article identifies the key lessons learned in terms of project implementation relating to attitudinal and structural barriers to the development of an age-friendly environment in areas of rapid urban growth. The findings illustrate some of the dilemmas raised by competing program conceptions, a dynamic and changing federal/state policy context, and local resource and strategic management constraints. The partnership with the university, nevertheless, provided a point of stability and continuity for the project officers in implementing their mandate. PMID:24224881

  6. 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.

  7. Age and growth of the midwater crocodile shark Pseudocarcharias kamoharai.

    PubMed

    Lessa, R; Andrade, H A; De Lima, K L; Santana, F M

    2016-07-01

    Age and growth were analysed on the basis of 372 vertebrae from specimens of the crocodile shark Pseudocarcharias kamoharai (66·0-122·0 cm, total length, LT ) collected in the south-western Atlantic Ocean. Centrum edge analysis suggested the first four months of the year as the period of band completion, leading to acceptance of free-living bands as annual. A pre-birth ring is formed in embryos >31·0 cm LT , whereas the birthmark is deposited in newborns of 46·1 ± 1·1 cm LT (mean ± s.d.). Growth was parameterized using seven models and the AIC was used for selection of the most plausible model. The von Bertalanffy growth model received the greatest support from the data, providing the following growth parameters for combined sexes: L∞ = 129·2 cm, k = 0·137 year(-1) and t0 = -3·9 years. No significant differences were detected in growth by sex, but significant differences in age composition by sex were found in the sample. Overall age ranged from 2 to >13 years in females and from 1 to 8 years in males. Males achieved first maturity at 3·1 years and females at 5·1 years, with pregnancy appearing at 4·8 years. Similar to other lamnoid species, P. kamoharai is relatively fast growing. PMID:26179442

  8. 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…

  9. 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

  10. 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.

  11. Saguaro (Carnegiea gigantea, Cactaceae) age-height relationships and growth: the development of a general growth curve.

    PubMed

    Drezner, Taly Dawn

    2003-06-01

    Because the growth rate of saguaros varies across different environments, past studies on saguaro population structure required extensive data collection (often over many decades) followed by site-specific analysis to estimate age at the sampled locale. However, when height-growth data from different populations are compared, the overall shape of the growth curves is similar. In this study, a formula was developed to establish saguaro age-height relationships (using stepwise regression) that can be applied to any saguaro population and only requires a site-specific factor to adjust the curve to the local growth rate. This adjustment factor can be established more efficiently and requires less data than the full analyses required for previous studies. Saguaro National Park East (SNP-E) was used as the baseline factor, set to 1.0. Results yielded a factor of 0.743 for SNP West. When the formula was applied to 10-yr interval data from Organ Pipe Cactus National Monument (OPCNM) in Arizona, USA, this location had a factor of 0.617 (relative to SNP-E). With this formula and relatively little field sampling, the age of any individual saguaro (whether the individual was sampled or not) in any population can be estimated. PMID:21659186

  12. AGE-STRUCTURAL TRANSITION IN INDONESIA

    PubMed Central

    Kreager, Philip; Schröder-Butterfill, Elisabeth

    2016-01-01

    This paper responds to recent calls for empirical study of the impact of age-structural transition. It begins by reviewing evidence of cohort oscillations in twentieth-century Indonesia, which indicates that current older generations are likely to have smaller numbers of children on whom they may rely than generations before and after them. However, to assess whether the imbalances implied by this situation are actually influencing people’s lives, attention to further factors shaping the availability and reliability of younger generations, notably differences in socio-economic status and in patterns of inter-generational support flows, is required. Community-level Indonesian data confirm that elders in the lower social strata are child-poor. Social structural and family network patterns, however, have a greater influence on the availability of inter-generational support than cohort differentials. PMID:27158254

  13. Contributions of Organic Vapors to Aerosol Aging and Growth

    NASA Astrophysics Data System (ADS)

    Zhang, R.; Wang, L.; Khalizov, A.

    2009-05-01

    Atmospheric aerosols impair visibility and human health, interfere with radiative transfer, and alter cloud formation. The major contributors include sulfate and organic aerosols from anthropogenic and biogenic activities, which are produced through a multitude of complex multiphase atmospheric processes by photochemical oxidation of emitted sulfur dioxide and volatile organic compounds (VOCs) into less volatile forms and gas-to-particle conversion. Condensation of organic vapors onto the pre-existing atmospheric aerosols, followed by chemical reactions within the particles medium, is believed to be one of the major pathways that contribute to particle growth. Recent research has focused on the total mass increase on pre- existing seed particles, but the chemistry that determines the efficiency of organic uptake remains to be elucidated. This talk will focus on the growth of nano- to sub-micron sulfuric acid droplets exposed organic vapors. Experiments performed at different relative humidity and using different organic vapors (i.e., small alpha-dicarbonyls and large aldehydes) will be presented. The chemical mechanisms and size dependence of the particle growth will be demonstrated. Implications of the present results to aging and growth of aerosols under ambient conditions will be discussed.

  14. 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.

  15. 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

  16. Fractional Dynamics of Network Growth Constrained by Aging Node Interactions.

    PubMed

    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

  17. Age and growth of the round whitefish in Lake Michigan

    USGS Publications Warehouse

    Mraz, Donald

    1964-01-01

    The round whitefish, though rarely abundant, is widely distributed in northern waters. It is one of the least studied of the coregonines; the present report is but the second for Great Lakes waters. Commercial production in Lake Michigan has been tightly confined to the northern portion. The period 1924-30 showed the best production: 200,000 to 359,000 pounds. Since 1956, production has been around 10,000 pounds or less. The present age and growth study is based on 208 fish collected by gill net in December 1951. The relation between total length in inches (L) and the weight in ounces (W) is described by the equation log W = -2.7232 + 3.2940 log L. Age-group III made up 66.3 percent, and age-group IV, 20.6 percent of the sample; age-groups V, VI, and VII combined contributed only 5.9 percent. The average length for all fish in the sample was 14.5 inches. Growth was calculated from a previously published linear body-scale relation with an intercept of 1.1 inches on the axis of fish length. The increments of calculated length declined steadily from a maximum of 4.6 inches the first year to 1.0 inch the eighth. A 3-year-old Lake Michigan fish (12.3 inches) is as long as a 5-year-old Lake Superior fish, and an 8-year-old Lake Michigan fish (18.9 inches) is 0.9 inch longer than the oldest (12 years) from Lake Superior. The smallest mature males and females were in the length intervals 12.0-12.4 inches and 13.0-13.4 inches, respectively. All males over 1.4 inches and all females over 14.9 inches were mature. The youngest mature males were in age-group II; 36 percent of II-group males but none of the females were mature. All fish older than age-group III were mature.

  18. 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.

  19. "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. PMID:27267208

  20. Structural health management for aging aircraft

    NASA Astrophysics Data System (ADS)

    Ikegami, Roy; Haugse, Eric D.

    2001-06-01

    An effective structural health management (SHM) system can be a useful tool for making aircraft fleet management decisions ranging from individual aircraft maintenance scheduling and usage restrictions to fleet rotation strategies. This paper discusses the end-user requirements for the elements and architecture of an effective SHM system for application to both military and commercial aging aircraft fleets. The elements discussed include the sensor systems for monitoring and characterizing the health of the structure, data processing methods for interpreting sensor data and converting it into useable information, and automated methods for erroneous data detection, data archiving and information dissemination. Current and past SHM technology development/maturation efforts in these areas at the Boeing Company will be described. An evolutionary technology development strategy is developed in which the technologies needed will be matured, integrated into a vehicle health management system, and benefits established without requiring extensive changes to the end-user's existing operation and maintenance infrastructure. Issues regarding the end-user customer acceptance of SHM systems are discussed and summarized.

  1. Role of growth factors in the human endometrium during aging.

    PubMed

    Leone, M; Costantini, C; Gallo, G; Voci, A; Massajoli, M; Messeni Leone, M; de Cecco, L

    1993-01-01

    The aim of this study was to investigate the possible role of epidermal growth factor (EGF) and of insulin-like growth factor-I (IGF-I) in physiological and pathological changes of the endometrial tissue during aging. Thirty-four patients undergoing hysterectomy were divided into three groups: (A) premenopausal women with regular menses, (B) pre-menopausal women with irregular bleeding and (C) post-menopausal women. Endometrial samples were collected after the removal of uterus and were used for immunohistochemical evaluation of EGF, EGF receptor (EGFr) and IGF-I and also for Northern blot analysis of IGF-I gene expression. Plasma levels of 17 beta-oestradiol (E2), D4-androstenedione (D4-A) and oestrone (E1) were also assayed. The immunohistochemical scores (HSCORES) for EGF, EGFr and IGF-I were significantly higher in groups A and B than in group C. Independently from the menstrual history, significantly higher HSCORES of EGF, EGFr and IGF-I were present in hyperplastic endometrium than in those which were proliferative and atrophic. Moreover, IGF-I mRNA expression was observed in all pre-menopausal women, whereas only 1 post-menopausal women with hyperplastic endometrium showed detectable RNA encoding for IGF-I. Higher levels of D4-A were also significantly correlated (P < 0.05) with higher HSCORES of EGF, EGFr and IGF-I. Our results suggest that the above mentioned growth factors could act as mediators of oestrogens on the endometrial functional activity. PMID:7679182

  2. Preliminary age, growth and maturity estimates of spotted ratfish (Hydrolagus colliei) in British Columbia

    NASA Astrophysics Data System (ADS)

    King, J. R.; McPhie, R. P.

    2015-05-01

    The spotted ratfish (Hydrolagus colliei) is a chimaeroid ranging from southeast Alaska to Baja California and found at depths of up to 1029 m. Despite being widespread and ubiquitous, few biological parameter estimates exist for spotted ratfish due to a lack of suitable ageing structures to estimate age and growth. We present preliminary results of age, growth and maturity estimates based on a new method in which tritor ridges are counted on the vomerine tooth plate. We also provide a method for estimating the number of worn tritor ridges based on tooth plate diameter measurements for the spotted ratfish. The tritor ridges are distinct bumps that are easy to identify and precision estimates between readers suggests that this method is transferable. Tritor ridges are a potential structure for estimating age in H. colliei and we provide recommendations for future research to improve the method. We sampled 269 spotted ratfish captured in trawl surveys off the coast British Columbia ranging in size from 74 to 495 mm in precaudal length (PCL). The estimated ages ranged from 2 to 16 years for males and from 2 to 21 years for females. The von Bertalanffy, von Bertalanffy with known size at birth, Gompertz and logistic growth models were fitted to the data. Based on Akaike information criterion corrected for sample size and number of parameters estimated, the logistic growth curve was selected as most suitable. The logistic growth model yielded the following parameter estimates: Linf=407.22 mm (PCL), k=0.23 year-1, t0=-7.06 years for males; L∞=494.52 mm (PCL), k=0.26 year-1, t0=-8.35 years for females. Estimated ages at 50% maturity were 12 and 14 years for males and females, respectively. Correspondingly, the size at 50% maturity estimates was smaller for males (302 mm, PCL) than females (393 mm, PCL). Both estimates are larger than those made for spotted ratfish off of California indicating regional differences in life history traits for this species. Our preliminary

  3. Perceptual information for the age level of faces as a higher order invariant of growth.

    PubMed

    Pittenger, J B; Shaw, R E; Mark, L S

    1979-08-01

    Previous work supports the hypothesis that cardioidal strain, a nonlinear topological transformation, offers a plausible mathematical model for the perceived global changes in human craniofacial morphology due to growth. Experiment 1 examined the generality of the effect of this growth transformation on relative age judgments by applying it to profiles of a dog, bird, and monkey. Experiment 2 investigated the abstractness of this transformation by looking at its effect on perceived age level of a Volkswagen "Beetle." In both experiments, cardioidal strain resulted in changes in the perceived age of the nonhuman profiles that were similar to those produced on human faces in earlier work. A second transformation, affine shear, failed to produce as significant an effect on perceived age as cardioidal strain when applied to the same structures. Because cardioidal strain produces changes in structures that do not share an isomorphism of rigid (Euclidian) local features or rigid feature configurations, this transformation seems both sufficiently general and abstract to specify what J.J. Gibson has called a "higher-order invariant of perceptual information. PMID:528953

  4. Discontinuous Growth of Onion Structure under Shear

    NASA Astrophysics Data System (ADS)

    Fujii, Shuji

    Discontinuous growth process of the Multilamellar vesicle (so called Onion) driven by shear quench was investigated by viscometry and microscopy in detail. Discontinuous Onion growth was observed when the final shear rate corresponded to the intermediate shear rate domain where the shear-thickening and shear-thinning viscosity appeared. In this process, large Onion transformed back into the lamellae and then formed large Onion. Small Onion to lamellae degradation process might be achieved by two modes, first the disruption of the configurational order of densely packed Onions followed by the rupture of Onion as second process. The second process would be characterized by the shear-banding flow pattern composed of the Onion-Lα coexisting state. We suggest that the appearance of the shear-band structure and the Onion reformation developed from the shear-band might be scaled by considering the mechanical energy balance with the bending elastic energy of bilayers.

  5. Growth, contacting and ageing of superconducting Bi-2212 whiskers

    NASA Astrophysics Data System (ADS)

    Truccato, M.; Rinaudo, G.; Manfredotti, C.; Agostino, A.; Benzi, P.; Volpe, P.; Paolini, C.; Olivero, P.

    2002-09-01

    We report the growth of highly oriented microscopic whisker-like crystals in the Bi-Sr-Ca-Cu-O system by means of glassy precursors. The dependence of the growth on the stoichiometric composition and on the temperature and duration of the annealing process has been studied. Chemical impurities have been investigated from the point of view of the morphology, the elemental composition and the crystal structure, identifying the presence of CuAl2O4, Sr1.2Bi0.8O3 and Al. Electrical contacts have been fabricated by means of thermal evaporation and diffusion. Their sizes have been carefully measured, achieving contact resistivity in the range of 0.2-3.7 × 10-6 Ω cm2. A very slow degrading of the contacts and the crystals on a time scale of a few years has been detected. This is associated with a decrease in Tc, which is probably due to oxygen release from the material.

  6. Changing family structure and aging issues.

    PubMed

    Bae, H

    1987-12-01

    Rapid industrialization, adaptation of modern values, and rural-urban migration in Korea have led to the replacement of the extended family with the nuclear of conjugal family. In 1980, 13% of Korean households were 1-generational, 70% were 2-generational, 17% were 3-generational and less than 1% were 4-generational. This trend has had serious implications for the aged, who have become increasingly isolated from Korean society. Hindering the adaptation of the aged to modern society are their low educational level, rural concentration, low income, and high rate of female members. Adult children who are well educated and prosperous economically are most likely to refuse to take responsibility for aged parents. Since some 23% of the aged currently live alone, Korean society must assume some of the responsibility that has traditionally been accepted by family members. There is a need for systematic programming that takes into account the current sociodemographic circumstances of Korea's aged population. Incentives such as tax exemptions and aged care allowances should be considered to encourage children to take responsibility for their aged parents. To meet the needs of the growing number of aged who are disabled and without family support, the number of geriatric hospitals and institutions must be expanded. Also important are supplementary programs such as housekeeping services, meals on wheels, and day care. Although the expansion of social welfare programs and institutions for the aged is essential, they can not in themselves meet the emotional needs of the aged that have traditionally been served by family connectedness. PMID:12315151

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

    PubMed

    Dasinger, John Henry; Intapad, Suttira; Backstrom, Miles A; Carter, Anthony J; Alexander, Barbara T

    2016-08-01

    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

  8. Ages and Growth of the Continental Crust from Radiogenic Isotopes

    NASA Astrophysics Data System (ADS)

    Patchett, P. J.; Samson, S. D.

    2003-12-01

    The development and application of radiogenic isotopes to dating of geologic events, and to questions of growth, evolution, and recycling processes in the continental crust are mature areas of scientific inquiry. By this we understand that many of the approaches used to date rocks and constrain the evolution of the continents are well established, even routine, and that the scope of data available on age and evolution of continents is very large. This is not to say that new approaches have not been developed in recent years, or that new approaches and/or insights cannot be developed in the future. However, the science of continental crustal evolution is definitely a domain where many of the problems are well defined, the power of the techniques used to solve them are well known, and the limitations of field and laboratory databases, as well as the preserved geologic record, are understood.From the very early days of crustal evolution studies, it was innovations and improvements in laboratory techniques that drove the pace of discovery (e.g., Holmes, 1911; Nier, 1939). This remained true through all the increments in capability reviewed in this chapter, up to the present day. Thus, continental crustal evolution is an area of Earth science where a species of very laboratory-oriented investigator, the "radiogenic isotope geologist" or "geochronologist," has made major advances, even breakthroughs, in understanding. This is true in spite of the fact that many of the individuals of the species may have lacked field expertise, or even more than a primitive level of geologic background. Because design and building of instruments like radiation detectors or mass spectrometers requires a knowledge of physics, many of the early practitioners of rock dating were physicists, like Alfred Nier (cited above). Since the 1970s, essentially all mass spectrometers have been constructed by specialized commercial firms, and the level of physics expertise among isotope geologists has

  9. 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. PMID:27073155

  10. Growth and development of female dancers aged 8-16 years.

    PubMed

    Steinberg, Nili; Siev-Ner, Itzhak; Peleg, Smadar; Dar, Gali; Masharawi, Youssef; Hershkovitz, Israel

    2008-01-01

    Little data are available on the growth and development of young female dancers. The objective of this study was to determine whether the body structure and adipose tissue distribution of dancers aged 8-16 years differ from that of non-dancer girls. Our cross-sectional study included a group of 1,482 female dancers, aged 8-16 years, and a control group of 226 female non-dancers of similar age cohorts. Fourteen anthropometric measurements were recorded and 15 indices calculated. In none of the linear anthropometric measures, were significant differences found between the two groups. The only significant difference relates to the extent and distribution of adipose tissue: At age 8, both groups show similar weight while at age 13 non-dancers are significantly heavier than dancers (48.4 +/- 9.8 kg for non-dancers and 40.6 +/- 8.7 kg for dancers). At age 15, weight differences between the two groups decrease to only 2 kg. The differences in weight are also expressed in skinfold thickness and chest circumference. Patterns of adipose tissue distribution differ between the two groups. Mean age at menarche was 13.1 years among dancers and 12.3 years in non-dancers. In conclusion, musculoskeletal development was found to be very similar in dancers and non-dancers. The specific body type reported for professional dancers is more likely acquired via "teacher's selection" and not training programs. Parents should not dread the possibility that dance training will delay the growth or reduce the height of their daughters. PMID:18203124

  11. AN ATMOSPHERIC STRUCTURE EQUATION FOR GRAIN GROWTH

    SciTech Connect

    Ormel, C.W.

    2014-07-01

    We present a method to include the evolution of the grain size and grain opacity κ{sub gr} in the equations describing the structure of protoplanetary atmospheres. The key assumption of this method is that a single grain size dominates the grain size distribution at any height r. In addition to following grain growth, the method accounts for mass deposition by planetesimals and grain porosity. We illustrate this method by computation of a simplified atmosphere structure model. In agreement with previous works, grain coagulation is seen to be very efficient. The opacity drops to values much below the often-used ''interstellar medium opacities'' (∼1 cm{sup 2} g{sup –1}) and the atmosphere structure profiles for temperature and density resemble that of the grain-free case. Deposition of planetesimals in the radiative part of the atmosphere hardly influences this outcome as the added surface is quickly coagulated away. We observe a modest dependence on the internal structure (porosity), but show that filling factors cannot become too large because of compression by gas drag.

  12. Linear growth of structure in massive bigravity

    SciTech Connect

    Solomon, Adam R.; Akrami, Yashar; Koivisto, Tomi S. E-mail: yashar.akrami@astro.uio.no

    2014-10-01

    The ghost-free theory of massive gravity with two dynamical metrics has been shown to produce viable cosmological expansion, where the late-time acceleration of the Universe is due to the finite range of the gravitational interaction rather than a nonzero cosmological constant. Here the cosmological perturbations are studied in this theory. The full perturbation equations are presented in a general gauge and analyzed, focusing on subhorizon scales in the quasistatic limit during the matter-dominated era. An evolution equation for the matter inhomogeneities and the parameters quantifying the deviations from general relativistic structure formation are expressed in terms of five functions whose forms are determined directly by the coupling parameters in the theory. The evolution equation has a similar structure to Horndeski-type scalar-tensor theories, exhibiting a modified growth rate and scale-dependence at intermediate wavenumbers. Predictions of the theory are confronted with observational data on both background expansion and large-scale structure, although care must be taken to ensure a model is stable. It is found that while the stable models fit the data well, they feature deviations from the standard cosmology that could be detected or ruled out by near-future experiments.

  13. Structural aging program -- a summary of activities, results, and conclusions

    SciTech Connect

    Naus, D.J.; Oland, C.B.; Ellingwood, B.R.

    1997-01-01

    Research has been conducted by the Oak Ridge National Laboratory to address aging management of nuclear power plant concrete structures. The purpose was to identify potential structural safety issues and acceptance criteria for use in continued service assessments. Primary program accomplishments have included formulation of a Structural Materials Information Center that contains data and information on the time variation of material properties under the influence of pertinent environmental stressors and aging factors for 144 materials, an aging assessment methodology to identify critical structures and degradation factors that can potentially impact their performance, guidelines and evaluation criteria for use in condition assessments of reinforced concrete structures, and a reliability-based methodology for current condition assessments and estimations of future performance of reinforced concrete nuclear power plant structures. In addition, the Structural Aging Program conducted in-depth evaluations of several nondestructive evaluation and repair-related technologies to develop guidance on their applicability.

  14. Simulation of population growth and structure of the population

    NASA Astrophysics Data System (ADS)

    Maksymowicz, A. Z.

    2002-08-01

    A computer study of population growth and biological ageing in the Penna model is presented. The stress is put on the analysis of the age structure and the distribution of 'bad' mutations m in the population. Results of computer simulation are compared with the simplest logistic model approach which ignores genetic contribution to the life game and accounts only for death due to limited environmental capacity, the Verhulst factor. The Penna model accounts also for genetic load and results of the simulation show that the final population essentially consists of the fittest individuals, as is expected. A more detailed analysis of the genome structure Δ( m) discloses significant marks of the history. The main conclusions are: (a) there is a clear correlation between population n, age a and the number m of bad mutations and (b) there is no correlation between particular configurations Δ( m) of genomes of the same m and the fraction of the population of this characteristics Δ( m). A typical run takes a couple of hours on an HP EXEMPLAR machine, and for a population of about n=10 6.

  15. Etropus crossotus, an annual flatfish species; age and growth of the fringed flounder in South Carolina

    NASA Astrophysics Data System (ADS)

    Reichert, Marcel J. M.

    1998-12-01

    Fringed flounder, Etropus crossotus, a small flatfish common along the southeastern coast of the US, were collected along the South Carolina coast in the fall of 1992, and in the North Inlet estuary from August 1992 until July 1994. Standard length was 82% of total length and the relationship between standard length and wet weight showed near-isometric growth with no significant differences between males and females. Dry weight was 21% of wet weight and ash-free dry weight 14% of wet weight with no significant differences between sexes. Daily increments in the sagittal otoliths were used for age determination. No annual structures could be identified. The maximum age was about 14.5 months. Age-at-length was not different between the sexes. The relationship between age and length was exponential, with age (in days) equalling an e power of 4.242 + 0.135 × standard length (in cm). Back-calculated hatch dates and catches of early juveniles indicated a spawning season that lasted from March to October. Females started to be sexually mature at 7 to 7.5 cm standard length, but 50% maturity was reached at 8 to 8.5 cm. Females could grow to that size within one spawning season. Individuals hatched early in the spawning season could produce eggs in the latter portion of that season's spawning period.

  16. Changes in the microvascular network during cardiac growth, development, and aging.

    PubMed

    Rakusan, K; Cicutti, N; Flanagan, M F

    1994-01-01

    Quantitative changes in the terminal vascular bed of the mammalian heart were assessed during postnatal development and aging. The most striking feature is a considerable formation of new capillaries in the early postnatal period, accompanied by a moderate formation of new arterioles. On the other hand, coronary arterioles seem to disappear at a higher rate than capillaries in the senescent heart. We proposed a three-dimensional structural model of tissue capillary supply, defined as capillary domain area times capillary segment length. This so called capillary supply unit increases as a function of age and body growth. It is very similar in size and shape (length to width ratio) to cardiac myocytes. PMID:7849763

  17. Diverse Roles of Growth Hormone and Insulin-Like Growth Factor-1 in Mammalian Aging: Progress and Controversies

    PubMed Central

    Csiszar, Anna; de Cabo, Raphael; Ferrucci, Luigi; Ungvari, Zoltan

    2012-01-01

    Because the initial reports demonstrating that circulating growth hormone and insulin-like growth factor-1 decrease with age in laboratory animals and humans, there have been numerous studies related to the importance of these hormones for healthy aging. Nevertheless, the role of these potent anabolic hormones in the genesis of the aging phenotype remains controversial. In this chapter, we review the studies demonstrating the beneficial and deleterious effects of growth hormone and insulin-like growth factor-1 deficiency and explore their effects on specific tissues and pathology as well as their potentially unique effects early during development. Based on this review, we conclude that the perceived contradictory roles of growth hormone and insulin-like growth factor-1 in the genesis of the aging phenotype should not be interpreted as a controversy on whether growth hormone or insulin-like growth factor-1 increases or decreases life span but rather as an opportunity to explore the complex roles of these hormones during specific stages of the life span. PMID:22522510

  18. Growth signaling promotes chronological aging in budding yeast by inducing superoxide anions that inhibit quiescence

    PubMed Central

    Weinberger, Martin; Mesquita, Ana; Carroll, Timothy; Marks, Laura; Yang, Hui; Zhang, Zhaojie; Ludovico, Paula; Burhans, William C.

    2010-01-01

    Inhibition of growth signaling pathways protects against aging and age-related diseases in parallel with reduced oxidative stress. The relationships between growth signaling, oxidative stress and aging remain unclear. Here we report that in Saccharomyces cerevisiae, alterations in growth signaling pathways impact levels of superoxide anions that promote chronological aging and inhibit growth arrest of stationary phase cells in G0/G1. Factors that decrease intracellular superoxide anions in parallel with enhanced longevity and more efficient G0/G1 arrest include genetic inactivation of growth signaling pathways that inhibit Rim15p, which activates oxidative stress responses, and downregulation of these pathways by caloric restriction. Caloric restriction also reduces superoxide anions independently of Rim15p by elevating levels of H2O2, which activates superoxide dismutases. In contrast, high glucose or mutations that activate growth signaling accelerate chronological aging in parallel with increased superoxide anions and reduced efficiency of stationary phase G0/G1 arrest. High glucose also activates DNA damage responses and preferentially kills stationary phase cells that fail to arrest growth in G0/G1. These findings suggest that growth signaling promotes chronological aging in budding yeast by elevating superoxide anions that inhibit quiescence and induce DNA replication stress. A similar mechanism likely contributes to aging and age-related diseases in complex eukaryotes. PMID:21076178

  19. Inferring Selection Intensity and Allele Age from Multilocus Haplotype Structure

    PubMed Central

    Chen, Hua; Slatkin, Montgomery

    2013-01-01

    It is a challenging task to infer selection intensity and allele age from population genetic data. Here we present a method that can efficiently estimate selection intensity and allele age from the multilocus haplotype structure in the vicinity of a segregating mutant under positive selection. We use a structured-coalescent approach to model the effect of directional selection on the gene genealogies of neutral markers linked to the selected mutant. The frequency trajectory of the selected allele follows the Wright-Fisher model. Given the position of the selected mutant, we propose a simplified multilocus haplotype model that can efficiently model the dynamics of the ancestral haplotypes under the joint influence of selection and recombination. This model approximates the ancestral genealogies of the sample, which reduces the number of states from an exponential function of the number of single-nucleotide polymorphism loci to a quadratic function. That allows parameter inference from data covering DNA regions as large as several hundred kilo-bases. Importance sampling algorithms are adopted to evaluate the probability of a sample by exploring the space of both allele frequency trajectories of the selected mutation and gene genealogies of the linked sites. We demonstrate by simulation that the method can accurately estimate selection intensity for moderate and strong positive selection. We apply the method to a data set of the G6PD gene in an African population and obtain an estimate of 0.0456 (95% confidence interval 0.0144−0.0769) for the selection intensity. The proposed method is novel in jointly modeling the multilocus haplotype pattern caused by recombination and mutation, allowing the analysis of haplotype data in recombining regions. Moreover, the method is applicable to data from populations under exponential growth and a variety of other demographic histories. PMID:23797107

  20. 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.

  1. Nuclear Structure Data for the Present Age

    NASA Astrophysics Data System (ADS)

    Baglin, Coral M.

    2005-05-01

    The US Nuclear Data Program maintains and provides easy and free access to several comprehensive databases that assist scientists to sift through and assess the vast quantity of published nuclear structure and decay data. These databases are an invaluable asset for nuclear-science experimentalists and theorists alike, and the recommended values provided for nuclear properties such as decay modes, level energies and lifetimes, and radiation properties can also be of great importance to specialists in other fields such as medicine, geophysics, and reactor design. The Evaluated Nuclear Structure Data File (ENSDF) contains experimental nuclear structure data for all known nuclides, evaluated by the US nuclear data program evaluators in collaboration with a number of international data groups; the Nuclear Science Reference (NSR) database provides complementary bibliographic information; the Experimental Unevaluated Nuclear Data Listing (XUNDL) exists to enable rapid access to experimental nuclear-structure data compiled from the most recent publications (primarily in high-spin physics). This paper presents an overview of the nuclear structure and decay data available through these databases, with emphasis on recent and forthcoming additions to and presentations of the available material.

  2. Age and growth of the tiger shark Galeocerdo cuvier off the east coast of Australia.

    PubMed

    Holmes, B J; Peddemors, V M; Gutteridge, A N; Geraghty, P T; Chan, R W K; Tibbetts, I R; Bennett, M B

    2015-08-01

    Total lengths (L(T)) at age and growth rates for south-west Pacific Galeocerdo cuvier were estimated from vertebral growth-band counts of 202 sagitally sectioned centra from 112 females (71-430 cm L(T)), 79 males (72-351 cm L(T)) and 11 of unknown sex. Captive growth data were also examined to complement vertebral age estimations. The sexes combined modelled growth coefficient (k = 0.08) was smaller than previously reported for G. cuvier populations elsewhere. Split-band and narrow banding patterns were identified as potential sources of age underestimation in this species. PMID:26248806

  3. Infant Gaze Following and Pointing Predict Accelerated Vocabulary Growth through Two Years of Age: A Longitudinal, Growth Curve Modeling Study

    ERIC Educational Resources Information Center

    Brooks, Rechele; Meltzoff, Andrew N.

    2008-01-01

    We found that infant gaze following and pointing predicts subsequent language development. At ages 0 ; 10 or 0 ; 11, infants saw an adult turn to look at an object in an experimental setting. Productive vocabulary was assessed longitudinally through two years of age. Growth curve modeling showed that infants who gaze followed and looked longer at…

  4. Review of growth plate closure compared with age at sexual maturity and lifespan in laboratory animals.

    PubMed

    Kilborn, Susan H; Trudel, Guy; Uhthoff, Hans

    2002-09-01

    Although it is assumed that most mammals experience growth plate closure and cessation of bone growth soon after sexual maturity, bone growth in rats continues throughout their lifespan. The rat was compared to other laboratory animals to assess differences in the duration of bone growth and its relationship to age at sexual maturity and lifespan. We reviewed the literature from 1966 to March 1999 by searching MEDLINE and other databases. Growth closure times and age at sexual maturity were retrieved for the mouse, rabbit, dog, cat, sheep, cow, horse, nonhuman primates, and human. For all species, we calculated the ratios of: 1) age at growth plate closure to lifespan, 2) age at growth plate closure to age at sexual maturity, and 3) age at sexual maturity to average lifespan. The ratio of age at physis closure to the average lifespan was large for the rat (22 to 35) and showed some overlap with that of humans (17 to 25); this ratio was comparatively small in all other nonhuman species (range, 4 to 17). This finding indicates that bone growth continues in the rat for a greater proportion of their lifespan than does that in other species. The ratio of age at physis closure to age at sexual maturity was larger for the rat (5 to 6) than that for other species, indicating that bone growth continues much longer after sexual maturity in rats than in other animals. The ratio of age at sexual maturity to average lifespan was largest for humans and nonhuman primates (13 to 14), indicating the increased time to reach puberty versus that in other species. These differences are important for studies in which animal models are used in research involving bone growth. PMID:12213043

  5. Zircon Age Episodicity and Growth of Continental Crust

    NASA Astrophysics Data System (ADS)

    Condie, Kent C.; Aster, Richard C.

    2009-10-01

    Granites form when silica-rich magma intrudes into the crust and slowly crystallizes. Such intrusions are discontinuous in space and episodic in time, resulting in a mosaic of ages for granites from a given region. Although the episodicity of granitoid ages is well known [Condie, 1998; Kemp et al., 2006], how representative samples are of age distributions in the preserved continental crust is unclear. This is because sampling strategies are generally dictated by mineral exploration, accessibility of outcrops, or availability of geologic maps, none of which necessarily leads to an unbiased representation of age distributions in the continental crust. For instance, large age peaks at 2.7 and 1.9 billion years ago in the Canadian and Baltic shields may reflect extensive sampling of these shields [Condie et al., 2009a].

  6. Evaluation of aging degradation of structural components

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1992-03-01

    Irradiation embrittlement of the neutron shield tank (NST) A212 Grade B steel from the Shippingport reactor, as well as thermal embrittlement of CF-8 cast stainless steel components from the Shippingport and KRB reactors, has been characterized. Increases in Charpy transition temperature (CTT), yield stress, and hardness of the NST material in the low-temperature low-flux environment are consistent with the test reactor data for irradiations at < 232{degrees}C. The shift in CTT is not as severe as that observed in surveillance samples from the High Flux Isotope Reactor (HFIR): however, it shows very good agreement with the results for HFIR A212-B steel irradiated in the Oak Ridge Research Reactor. The results indicate that fluence rate has not effect on radiation embrittlement at rates as low as 2 {times} 10{sup 8} n/cm{sup 2}{center dot}s at the low operating temperature of the Shippingport NST, i.e., 55{degrees}C. This suggest that radiation damage in Shippingport NST and HFIR surveillance samples may be different because of the neutron spectra and/or Cu and Ni content of the two materials. Cast stainless steel components show relatively modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength. Correlations for estimating mechanical properties of cast stainless steels predict accurate or slightly conservative values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predict the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y.

  7. Evaluation of aging degradation of structural components

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1992-03-01

    Irradiation embrittlement of the neutron shield tank (NST) A212 Grade B steel from the Shippingport reactor, as well as thermal embrittlement of CF-8 cast stainless steel components from the Shippingport and KRB reactors, has been characterized. Increases in Charpy transition temperature (CTT), yield stress, and hardness of the NST material in the low-temperature low-flux environment are consistent with the test reactor data for irradiations at < 232{degrees}C. The shift in CTT is not as severe as that observed in surveillance samples from the High Flux Isotope Reactor (HFIR): however, it shows very good agreement with the results for HFIR A212-B steel irradiated in the Oak Ridge Research Reactor. The results indicate that fluence rate has not effect on radiation embrittlement at rates as low as 2 {times} 10{sup 8} n/cm{sup 2}{center_dot}s at the low operating temperature of the Shippingport NST, i.e., 55{degrees}C. This suggest that radiation damage in Shippingport NST and HFIR surveillance samples may be different because of the neutron spectra and/or Cu and Ni content of the two materials. Cast stainless steel components show relatively modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength. Correlations for estimating mechanical properties of cast stainless steels predict accurate or slightly conservative values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predict the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y.

  8. 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

  9. Age effect on subcortical structures in healthy adults

    PubMed Central

    Goodro, Matt; Sameti, Mohammad; Patenaude, Brian; Fein, George

    2012-01-01

    Cross-sectional age effects in normal control volunteers were investigated in 8 subcortical structures: lateral ventricles, thalamus, caudate, putamen, pallidum, hippocampus, amygdala and nucleus accumbens. Two hundred and twenty six control subjects, ranging in age from 19 to 85 years, were scanned on a 1.5T GE system (n = 184) or a 3.0T Siemens system (n = 42). Cranium-size adjusted subcortical structure volumes were estimated using FSL’s FIRST software, which is fully automated. Significant age effects were found for all volumes when the entire age range was analyzed, however the older subjects (60–85 years of age) showed a stronger correlation between age and structural volume for the ventricles, hippocampus, amygdala and accumbens than middle-aged (35–60 years of age) subjects. Middle-aged subjects were studied at both sites, and age effects in these groups were comparable, despite differences in magnet strength and acquisition systems. This agreement lends support to the validity of the image analysis tools and procedures used in the present study. PMID:22863654

  10. Age and growth of rock bass in eastern Lake Ontario

    USGS Publications Warehouse

    Wolfert, David R.

    1980-01-01

    To test the reliability of current techniques, five biologists appraised the ages of 200 quail from a random sample of wings collected during the 1952-53 hunting season in Alabama. Attempt was made to distinguish adults from juveniles, to ascertain the stage of post-nuptial and post-juvenile molts, and to estimate the age of juveniles according to days or weeks. Three 'problem' wings in this sample had molt characteristics somewhat eauallv divided between adult and juvenile classes; two wings called 'questionable' had all molt characteristics except one of either age group. A 3.5 per cent disparity occurred between investigators in their classification of adult and juvenile age groups. This included not only 'problem' and 'questionable' wings, but also 'obvious errors.' Individual differences were greater than 3.5 per cent but cancelled out. This study emphasizes the need of working with large samples of birds of a known age in order to know more concerning molt variations. Until aging techniques can be refined, it is believed that investigators should be fully familiar with existing methods and their weaknesses. Also, it appears important that reports on aging should indicate clearly the techniques used.

  11. 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

  12. 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

  13. Anisotropic nanomaterials: structure, growth, assembly, and functions

    PubMed Central

    Sajanlal, Panikkanvalappil R.; Sreeprasad, Theruvakkattil S.; Samal, Akshaya K.; Pradeep, Thalappil

    2011-01-01

    Comprehensive knowledge over the shape of nanomaterials is a critical factor in designing devices with desired functions. Due to this reason, systematic efforts have been made to synthesize materials of diverse shape in the nanoscale regime. Anisotropic nanomaterials are a class of materials in which their properties are direction-dependent and more than one structural parameter is needed to describe them. Their unique and fine-tuned physical and chemical properties make them ideal candidates for devising new applications. In addition, the assembly of ordered one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) arrays of anisotropic nanoparticles brings novel properties into the resulting system, which would be entirely different from the properties of individual nanoparticles. This review presents an overview of current research in the area of anisotropic nanomaterials in general and noble metal nanoparticles in particular. We begin with an introduction to the advancements in this area followed by general aspects of the growth of anisotropic nanoparticles. Then we describe several important synthetic protocols for making anisotropic nanomaterials, followed by a summary of their assemblies, and conclude with major applications. PMID:22110867

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  15. Chromatin structure and transposable elements in organismal aging

    PubMed Central

    Wood, Jason G.; Helfand, Stephen L.

    2013-01-01

    Epigenetic regulatory mechanisms are increasingly appreciated as central to a diverse array of biological processes, including aging. An association between heterochromatic silencing and longevity has long been recognized in yeast, and in more recent years evidence has accumulated of age-related chromatin changes in Caenorhabditis elegans, Drosophila, and mouse model systems, as well as in the tissue culture-based replicative senescence model of cell aging. In addition, a number of studies have linked expression of transposable elements (TEs), as well as changes in the RNAi pathways that cells use to combat TEs, to the aging process. This review summarizes the recent evidence linking chromatin structure and function to aging, with a particular focus on the relationship of heterochromatin structure to organismal aging. PMID:24363663

  16. Localizing Age-Related Individual Differences in a Hierarchical Structure

    ERIC Educational Resources Information Center

    Salthouse, Timothy A.

    2004-01-01

    Data from 33 separate studies were combined to create an aggregate data set consisting of 16 cognitive variables and 6832 different individuals who ranged between 18 and 95 years of age. Analyses were conducted to determine where in a hierarchical structure of cognitive abilities individual differences associated with age, gender, education, and…

  17. Is Growth Differentiation Factor 11 a Realistic Therapeutic for Aging-Dependent Muscle Defects?

    PubMed

    Harper, Shavonn C; Brack, Andrew; MacDonnell, Scott; Franti, Michael; Olwin, Bradley B; Bailey, Beth A; Rudnicki, Michael A; Houser, Steven R

    2016-04-01

    This "Controversies in Cardiovascular Research" article evaluates the evidence for and against the hypothesis that the circulating blood level of growth differentiation factor 11 (GDF11) decreases in old age and that restoring normal GDF11 levels in old animals rejuvenates their skeletal muscle and reverses pathological cardiac hypertrophy and cardiac dysfunction. Studies supporting the original GDF11 hypothesis in skeletal and cardiac muscle have not been validated by several independent groups. These new studies have either found no effects of restoring normal GDF11 levels on cardiac structure and function or have shown that increasing GDF11 or its closely related family member growth differentiation factor 8 actually impairs skeletal muscle repair in old animals. One possible explanation for what seems to be mutually exclusive findings is that the original reagent used to measure GDF11 levels also detected many other molecules so that age-dependent changes in GDF11 are still not well known. The more important issue is whether increasing blood [GDF11] repairs old skeletal muscle and reverses age-related cardiac pathologies. There are substantial new and existing data showing that GDF8/11 can exacerbate rather than rejuvenate skeletal muscle injury in old animals. There is also new evidence disputing the idea that there is pathological hypertrophy in old C57bl6 mice and that GDF11 therapy can reverse cardiac pathologies. Finally, high [GDF11] causes reductions in body and heart weight in both young and old animals, suggestive of a cachexia effect. Our conclusion is that elevating blood levels of GDF11 in the aged might cause more harm than good. PMID:27034276

  18. CVD Growth of Carbon Nanotubes: Structure, Catalyst, and Growth

    NASA Technical Reports Server (NTRS)

    Delzeit, Lance

    2003-01-01

    Carbon nanotubes (CNTs) exhibit extraordinary mechanical and unique electronic properties and hence have been receiving much attention in recent years for their potential in nanoelectronics, field emission devices, scanning probes, high strength composites and many more applications. Catalytic decomposition of hydrocarbon feedstock with the aid of supported transition metal catalysts - also known as chemical vapor deposition (CVD) - has become popular to produce single-walled and multi-walled nanotubes (SWNTs, MWNTs) and multiwalled nanofibers (MWNFs). The ability to grow CNTs on patterned substrates and in vertically aligned arrays, and the simplicity of the process, has made CVD growth of CNTs an attractive approach.

  19. 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.

  20. 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.

  1. Demographic analysis from summaries of an age-structured population

    USGS Publications Warehouse

    Link, W.A.; Royle, J. Andrew; Hatfield, J.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.

  2. 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

  3. 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., III; 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

  4. Contributions of aging to the fatigue crack growth resistance of human dentin.

    PubMed

    Ivancik, Juliana; Majd, Hessam; Bajaj, Devendra; Romberg, Elaine; Arola, Dwayne

    2012-07-01

    An evaluation of the fatigue crack resistance of human dentin was conducted to identify the degree of degradation that arises with aging and the dependency on tubule orientation. Fatigue crack growth was achieved in specimens of coronal dentin through application of Mode I cyclic loading and over clinically relevant lengths (0 ≤ a ≤ 2 mm). The study considered two directions of cyclic crack growth in which the crack was either in-plane (0°) or perpendicular (90°) to the dentin tubules. Results showed that regardless of tubule orientation, aging of dentin is accompanied by a significant reduction in the resistance to the initiation of fatigue crack growth, as well as a significant increase in the rate of incremental extension. Perpendicular to the tubules, the fatigue crack exponent increased significantly (from m=14.2 ± 1.5 to 24.1 ± 5.0), suggesting an increase in brittleness of the tissue with age. For cracks extending in-plane with the tubules, the fatigue crack growth exponent does not change significantly with patient age (from m=25.4 ± 3.03 to 22.9 ± 5.3), but there is a significant increase in the incremental crack growth rate. Regardless of age, coronal dentin exhibits the lowest resistance to fatigue crack growth perpendicular to the tubules. While there are changes in the cyclic crack growth rate and mechanisms of cyclic extension with aging, this tissue maintains its anisotropy. PMID:22484693

  5. Contributions of Aging to the Fatigue Crack Growth Resistance of Human Dentin

    PubMed Central

    Ivancik, Juliana; Majd, Hessam; Bajaj, Devendra; Romberg, Elaine; Arola, Dwayne

    2012-01-01

    An evaluation of the fatigue crack resistance of human dentin was conducted to identify the degree of degradation that arises with aging and the dependency on tubule orientation. Fatigue crack growth was achieved in specimens of coronal dentin through application of Mode I cyclic loading and over clinically relevant lengths (0 ≤ a ≤ 2 mm). The study considered two directions of cyclic crack growth in which the crack was either in-plane (0°) or perpendicular (90°) to the dentin tubules. Results showed that regardless of tubule orientation, aging of dentin is accompanied by a significant reduction in the resistance to the initiation of fatigue crack growth, as well as a significant increase in the rate of incremental extension. Perpendicular to the tubules, the fatigue crack exponent increased significantly (from m=14.2±1.5 to 24.1±5.0), suggesting an increase in brittleness of the tissue with age. For cracks extending in plane with the tubules, the fatigue crack growth exponent does not change significantly with patient age (from m=25.4±3.03 to 22.9±5.3), but there is a significant increase in the incremental crack growth rate. Regardless of age, coronal dentin exhibits the lowest resistance to fatigue crack growth perpendicular to the tubules. While there are changes in the cyclic crack growth rate and mechanisms of cyclic extension with aging, this tissue maintains its anisotropy. PMID:22484693

  6. Structure and growth process of vapor-grown carbon fibers

    NASA Technical Reports Server (NTRS)

    Koyama, T.; Endo, M.

    1983-01-01

    The structure, effect of heat, and growth process of vapor-grown carbon fibers are investigated. The growth process of the carbon fibers could be divided into three stages; nucleation, elongation, and thickening processes. Also, a multi-layered structure can be produced as well as graphitization.

  7. Aging and demographic plasticity in response to experimental age structures in honeybees (Apis mellifera L)

    PubMed Central

    Linford, Robyn; Gardner, Preston; Coleman, Jennifer; Fine, Kari

    2008-01-01

    Honeybee colonies are highly integrated functional units characterized by a pronounced division of labor. Division of labor among workers is mainly age-based, with younger individuals focusing on in-hive tasks and older workers performing the more hazardous foraging activities. Thus, experimental disruption of the age composition of the worker hive population is expected to have profound consequences for colony function. Adaptive demography theory predicts that the natural hive age composition represents a colony-level adaptation and thus results in optimal hive performance. Alternatively, the hive age composition may be an epiphenomenon, resulting from individual life history optimization. We addressed these predictions by comparing individual worker longevity and brood production in hives that were composed of a single age cohort, two distinct age cohorts, and hives that had a continuous, natural age distribution. Four experimental replicates showed that colonies with a natural age composition did not consistently have a higher life expectancy and/or brood production than the single cohort or double cohort hives. Instead, a complex interplay of age structure, environmental conditions, colony size, brood production, and individual mortality emerged. A general trade-off between worker life expectancy and colony productivity was apparent, and the transition from in-hive tasks to foraging was the most significant predictor of worker lifespan irrespective of the colony age structure. We conclude that the natural age structure of honeybee hives is not a colony-level adaptation. Furthermore, our results show that honeybees exhibit pronounced demographic plasticity in addition to behavioral plasticity to react to demographic disturbances of their societies. PMID:18663386

  8. Effects of Stand age Structure on Regional Carbon Budgets of Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Song, C.; Woodcock, C. E.

    2002-12-01

    This study has developed a two-stage modeling scheme to investigate the importance of age structure on regional carbon fluxes for the forests in the Pacific Northwest of the United States. In the first stage, an individual-based forest ecosystem carbon flux model (IntCarb) at stand scale is developed. IntCarb combines components from the ZELIG and CENTURY models to simulate forest growth and development, and heterotrophic respiration, respectively. Stand scale carbon fluxes simulated by IntCarb strongly depend on stand age. Due to its high variablity over large areas, forest age structure has to be taken into account for realistic estimation of carbon budgets. The RegCarb model is developed to estimate regional scale carbon fluxes based on forest age structure and adjusting for the nonrespiratory carbon losses, such as harvesting. Our initial estimate with RegCarb for the Pacific Northwest of the United States found that this region was a tremendous carbon source to the atmosphere from 1890 to 1990 due to intensive logging of old-growth forest, and is becoming a carbon sink since the last decade. Projections for the role of forests in this region in the global carbon cycle in the future strongly depend on the amount of timber to be harvested, i.e. how the age structure of forests in this region is to be altered.

  9. Further understanding of aged composite and adhesively bonded structures

    NASA Astrophysics Data System (ADS)

    Heslehurst, Rikard B.; Baird, John P.

    1996-11-01

    As the application of advanced composite materials and adhesively bonded components becomes increasingly numerous in aircraft structures, so is the number of aircraft containing such structures that can be classified in the aging aircraft category. The effect of environmental and in- service aging of such structures is not well known or understood, neither have NDE techniques been able to satisfactorily qualify and quantify the loss of structural integrity due to the aging process. This paper will present the latest developments in the practical use of a field portable holographic interferometric testing system. The system results, known as holographic interferograms, provide a better understanding of how a structure is behaving under realistic loads in the presence of defects, damage and material property aging. The system has been applied to a variety of defects in composite and adhesive bondlines, as well as artificial environmental aging of these materials. The holographic interferograms produced form these investigations will be briefly reviewed and their impact on structural integrity of the component discussed.

  10. [Healthcare expenditures growth: the red herring of demographic ageing?].

    PubMed

    Tenand, Marianne

    2016-02-01

    Demographic ageing is often deemed responsible for the massive increase in health expenditures experienced by developed countries. As the elderly consume more medical care than the rest of the population, how could the increase in the share of the 60 + not lead to a marked expansion of healthcare public and private budgets? Despite its apparent logics, such reasoning is fallacious: it ignores that medical care consumption depends on many factors beyond age, which have tremendously evolved in the last decades and may change again in the future. Based on French stylized facts, this article provides an overview of the international literature that aimed at disentangling the respective roles of population ageing and of the non-demographic factors in explaining the dynamics of health expenditures. Paradoxically, technical medical progress has been a major contributor to the increase of healthcare spending. Results from economics research lead to qualify the impact of demographic trends and call for more attention to the public policies decisions that shape healthcare systems. PMID:26936179

  11. What Makes You Stronger: Age and Cohort Differences in Personal Growth after Cancer

    PubMed Central

    Pudrovska, Tetyana

    2012-01-01

    Using two waves of the National Survey of Midlife Development in the United States, I compare changes in personal growth over a 10-year period among cancer survivors and individuals without cancer. Moreover, I examine joint effects of age and cohort on personal growth after a cancer diagnosis. The theoretical framework of this study integrates impairment, resilience, and thriving perspectives. Findings reveal that, although personal growth declines with age for all individuals regardless of cohort and cancer status, cancer slows the decline in personal growth with age in 1940s, 1950s, and 1960s birth cohorts, yet accelerates the age-related decline in the 1920s cohort. I argue that a sociological perspective can enhance our understanding of the interplay of developmental and socio-cultural influences on psychological adjustment to cancer. Seemingly idiosyncratic psychological reactions to cancer partly reflect macro-level processes represented by cohort differences. PMID:20943589

  12. 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.

  13. Effects of age and sex on the structural, chemical and technological characteristics of mule duck meat.

    PubMed

    Baeza, E; Salichon, M R; Marche, G; Wacrenier, N; Dominguez, B; Culioli, J

    2000-07-01

    1. The aim of the study was to analyse the effect of age and sex on the chemical, structural and technological characteristics of mule duck meat. 2. Ten males and 10 females were weighed and slaughtered at 8, 10, 11, 12 and 13 weeks of age. Weight, pH value, colour, tenderness and juice loss of breast muscle were determined. 3. The activities of 3 enzymes (citrate synthase, beta-hydroxyacyl CoA dehydrogenase, lactate dehydrogenase) which indicate muscular metabolic activity were assayed. 4. Chemical composition (moisture, lipids, proteins, minerals, lipid and phospholipid classes, fatty acid composition) of breast muscle was analysed. 5. Fibre type, fibre type percentage and cross-sectional areas were determined using histochemistry and an image analysis system. 6. For growth performance and muscular structure, the ideal slaughter age of mule ducks is 10 weeks of age. Chemical and technological analysis indicated that muscular maturity in Pectoralis major was reached at 11 weeks of age, but, at this age, breast lipid content is high. Moreover, after 10 weeks of age, food costs rapidly increased. 7. Lastly, sexual dimorphism for body weight is minor. In this study, at any given age, no significant differences between males and females were shown. Thus, it is possible to rear both sexes together and to slaughter them at the same age. PMID:11081424

  14. 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. PMID:23885591

  15. Membrane aging during cell growth ascertained by Laurdan generalized polarization.

    PubMed

    Parasassi, T; Di Stefano, M; Ravagnan, G; Sapora, O; Gratton, E

    1992-10-01

    The sensitivity of the fluorescent probe Laurdan to the phase state of lipids has been utilized to detect modifications in the composition and physical state of cell membranes during cell growth. In phospholipid vesicles, the Laurdan emission spectrum shows a 50-nm red shift by passing from the gel to the liquid-crystalline phase. The Generalized Polarization (GP) value has been used for the data treatment instead of the ratiometric method common in investigations utilizing other fluorescent probes that display spectral sensitivity to medium properties. The GP value can be measured easily and quickly and possesses all the properties of "classical" polarization, including the additivity rule. Once Laurdan limiting GP values have been established for the gel and the liquid-crystalline phase of lipids, the quantitative determination of coexisting phases in natural samples is possible. In the present work the observation of a relevant decrease in the fractional intensity of the liquid-crystalline phase in K562 cell membranes during 5 days of asynchronous growth is reported. A decrease in the "fluidity" of cell membranes in K562 cells kept in culture for several months is also reported. The procedure developed for labeling cell membranes with Laurdan is reported and the influence of cell metabolism on fluorescence parameters is discussed. Also discussed is the influence of cholesterol on Laurdan GP. PMID:1397095

  16. Growth of cosmic structure: Probing dark energy beyond expansion

    NASA Astrophysics Data System (ADS)

    Huterer, Dragan; Kirkby, David; Bean, Rachel; Connolly, Andrew; Dawson, Kyle; Dodelson, Scott; Evrard, August; Jain, Bhuvnesh; Jarvis, Michael; Linder, Eric; Mandelbaum, Rachel; May, Morgan; Raccanelli, Alvise; Reid, Beth; Rozo, Eduardo; Schmidt, Fabian; Sehgal, Neelima; Slosar, Anže; van Engelen, Alex; Wu, Hao-Yi; Zhao, Gongbo

    2015-03-01

    curvature, high density regime. Cosmological evolution provides a polar opposite test bed, probing how gravity behaves in the lowest curvature, low density environments. There are a number of different implementations of astrophysically relevant modifications of gravity. Generically, the models are able to reproduce the distance measurements while at the same time altering the growth of structure. In particular, as detailed below, the Poisson equation relating over-densities to gravitational potentials is altered, and the potential that determines the geodesics of relativistic particles (such as photons) differs from the potential that determines the motion of non-relativistic particles. Upcoming surveys will exploit these differences to determine whether the acceleration of the Universe is due to dark energy or to modified gravity. To realize this potential, both wide field imaging and spectroscopic redshift surveys play crucial roles. Projects including DES, eBOSS, DESI, PFS, LSST, Euclid, and WFIRST are in line to map more than a 1000 cubic-billion-light-year volume of the Universe. These will map the cosmic structure growth rate to 1% in the redshift range 0 < z < 2 , over the last 3/4 of the age of the Universe.

  17. 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

  18. 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. PMID:25592941

  19. Evaluation of the feasibility of international growth standards for school-aged children and adolescents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of an international growth standard for the screening, surveillance, and monitoring of school-aged children and adolescents has been motivated by two contemporaneous events: the global surge in childhood obesity and the release of a new international growth standard for infants and presc...

  20. Evaluation of the feasibility of international growth standards for school-aged children and adolescents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of an international growth standard for the screening, surveillance, and monitoring of school-aged children and adolescents has been motivated by 2 contemporaneous events, the global surge in childhood obesity, and the release of a new international growth standard for infants and pr...

  1. The lumbar extradural structure changes with increasing age.

    PubMed

    Igarashi, T; Hirabayashi, Y; Shimizu, R; Saitoh, K; Fukuda, H; Mitsuhata, H

    1997-02-01

    We have examined the extradural space using a flexible extraduroscope in 74 patients undergoing extradural anaesthesia at the L2-3 interspace. Extraduroscopy showed that the extradural space becomes widely patent and the fatty tissue in the extradural space diminishes with increasing age. We postulate that these age-related structural changes may affect the spread of local anaesthetic in the extradural space. PMID:9068330

  2. Exploring the vertical age structure of the Galactic disc

    NASA Astrophysics Data System (ADS)

    Casagrande, Luca

    While in external or high-redshift galaxies we can only measure integrated stellar properties at best, the Milky Way offers us the unique opportunity to study its individual baryonic components, including stars. We use oscillations measured in red giant stars by the Kepler satellite to derive stellar ages and explore the vertical age structure across few kpc of the Milky Way disc. We find that old stars dominate at increasing Galactic heights, whereas closer to the plane a rich zoology of ages exists. The age distribution of stars shows a smooth distribution over the last 10 Gyr, which together with a flat age-metallicity relation is consistent with a quiescent evolution for the Milky Way disc since a redshift of about two.

  3. Exploring the vertical age structure of the Galactic disc

    NASA Astrophysics Data System (ADS)

    Casagrande, Luca; Silva Aguirre, Victor; Schlesinger, Katharine J.; Stello, Dennis; Huber, Daniel; Serenelli, Aldo; Schoenrich, Ralph; Asplund, Martin; Feltzing, Sofia

    2015-08-01

    While in external or high-redshift galaxies we can only measure integrated stellar properties at best, the Milky Way offers us the unique opportunity to study its individual baryonic components, including stars. We use oscillations measured in giant stars by the Kepler satellite to derive stellar ages and explore the vertical age structure across few kpc of the Milky Way disc. We find that old stars dominate at increasing Galactic heights, whereas closer to the plane a rich zoology of ages exists. The age distribution of stars shows a smooth decline over the last 10 Gyr, which together with a flat age-metallicity relation is consistent with a quiescent evolution for the Milky Way disc since a redshift of about two.

  4. Age Differences within Secular IQ Trends: An Individual Growth Modeling Approach

    ERIC Educational Resources Information Center

    Kanaya, Tomoe; Ceci, Stephen J.; Scullin, Matthew H.

    2005-01-01

    Age differences within the yo-yo trend in IQ, caused when aging norms that produce inflated scores are replaced with new norms, were examined using longitudinal WISC, WISC-R and WISC-III records of students tested for special education services from 10 school districts. Descriptive and individual growth modeling analyses revealed that while the…

  5. Growth in Reading Achievement of Students with Disabilities, Ages 7 to 17

    ERIC Educational Resources Information Center

    Wei, Xin; Blackorby, Jose; Schiller, Ellen

    2011-01-01

    Using data from the Special Education Elementary Longitudinal Study (SRI International, 2002), this study estimated reading growth trajectories in a nationally representative sample of 3,421 students with disabilities ages 7 to 17 representing 11 federal disability categories. Reading achievement in all disability categories increased with age,…

  6. Edge crack growth of thermally aged graphite/polyimide composites

    NASA Technical Reports Server (NTRS)

    Nelson, J. B.

    1984-01-01

    Laminates of Celion 6000/LARC-160 and Celion 6000/PMR-15 graphite/polyimide composite materials were aged in air at temperatures of 202, 232, 260 and 288 C for various times up to 15,000 hours. Three unidirectional specimen types were studied: short beam shear (SBS), flexure, and 153 mm square panels. The interior region of the square panels exhibited little or no property degradation, whereas both laminate materials degraded and cracked preferentially at the specimen edge perpendicular to the fibers. Using a dye penetrant, the specimens were X-rayed and the crack depth measured as a function of time and temperature. A time temperature superposition of the crack data was successfully performed using an Arrhenius form for the shift factor. A direct correlation was found for edge crack depth and SBS strength for the LARC-160 laminates but the correlation for PMR-15 laminates was more complex.

  7. Report on aging of nuclear power plant reinforced concrete structures

    SciTech Connect

    Naus, D.J.; Oland, C.B.; Ellingwood, B.R.

    1996-03-01

    The Structural Aging Program provides the US Nuclear Regulatory Commission with potential structural safety issues and acceptance criteria for use in continued service assessments of nuclear power plant safety-related concrete structures. The program was organized under four task areas: Program Management, Materials Property Data Base, Structural Component Assessment/Repair Technology, and Quantitative Methodology for Continued Service Determinations. Under these tasks, over 90 papers and reports were prepared addressing pertinent aspects associated with aging management of nuclear power plant reinforced concrete structures. Contained in this report is a summary of program results in the form of information related to longevity of nuclear power plant reinforced concrete structures, a Structural Materials Information Center presenting data and information on the time variation of concrete materials under the influence of environmental stressors and aging factors, in-service inspection and condition assessments techniques, repair materials and methods, evaluation of nuclear power plant reinforced concrete structures, and a reliability-based methodology for current and future condition assessments. Recommendations for future activities are also provided. 308 refs., 61 figs., 50 tabs.

  8. Effect of thermal aging on the fatigue crack growth behavior of cast duplex stainless steels

    NASA Astrophysics Data System (ADS)

    Lü, Xu-ming; Li, Shi-lei; Zhang, Hai-long; Wang, Yan-li; Wang, Xi-tao

    2015-11-01

    The effect of thermal aging on the fatigue crack growth (FCG) behavior of Z3CN20?09M cast duplex stainless steel with low ferrite content was investigated in this study. The crack surfaces and crack growth paths were analyzed to clarify the FCG mechanisms. The microstructure and micromechanical properties before and after thermal aging were also studied. Spinodal decomposition in the aged ferrite phase led to an increase in the hardness and a decrease in the plastic deformation capacity, whereas the hardness and plastic deformation capacity of the austenite phase were almost unchanged after thermal aging. The aged material exhibited a better FCG resistance than the unaged material in the near-threshold regime because of the increased roughness-induced crack closure associated with the tortuous crack path and rougher fracture surface; however, the tendency was reversed in the Paris regime because of the cleavage fracture in the aged ferrite phases.

  9. Age at Weaning and Infant Growth: Primary Analysis and Systematic Review

    PubMed Central

    Vail, Brennan; Prentice, Philippa; Dunger, David B.; Hughes, Ieuan A.; Acerini, Carlo L.; Ong, Ken K.

    2015-01-01

    Objective To test whether earlier age at weaning (age 3-6 months) may promote faster growth during infancy. Study design Weaning at age 3.0-7.0 months was reported by 571 mothers of term singletons in a prospective birth cohort study conducted in Cambridge, UK. Infant weight and length were measured at birth and at age 3 months and 12 months. Anthropometric values were transformed into age- and sex-adjusted z-scores. Three linear regression models were performed, including adjustment for confounders in a stepwise manner. Measurements at age 3 months, before weaning, were used to consider reverse causality. Results Almost three-quarters (72.9%) of infants were weaned before age 6 months. Age at weaning of 3.0-7.0 months was inversely associated with weight and length (but not with body mass index) at 12 months (both P ≤ .01, adjusted for maternal and demographic factors). These associations were attenuated after adjustment for type of milk feeding and weight or length at age 3 months (before weaning). Rapid weight gain between 0 and 3 months predicted subsequent earlier age at weaning (P = .01). Our systematic review identified 2 trials, both reporting null effects of age at weaning on growth, and 15 observational studies, with 10 reporting an inverse association between age at weaning and infant growth and 4 reporting evidence of reverse causality. Conclusion In high-income countries, weaning between 3 and 6 months appears to have a neutral effect on infant growth. Inverse associations are likely related to reverse causality. PMID:26073105

  10. The LMS and Z Scale Growth Reference for Saudi School-age Children and Adolescents

    PubMed Central

    El Mouzan, Mohammad I.; Al Salloum, Abdullah A.; Alqurashi, Mansour M.; Al Herbish, Abdullah S.; Al Omar, Ahmad

    2016-01-01

    Background/Aim: To establish L, M, and S parameters and z score reference for the assessment of nutrition and growth of Saudi school-age children and adolescents. Subjects and Methods: Data from the original cross-sectional study were reanalyzed. The L, M, and S parameters and z scores were calculated for weight, height and body mass index for school-age children and adolescents. Results: A total of 19,299 subjects from 5 to 18 years of age were included. All were Saudi nationals and 9,827 (50.9%) were boys. The L M S parameters and z scores for weight for age, height for age, and BMI for age for boys and girls are presented in detailed tables across the age of commonly used z scores (+3, +2, +1, 0, -1, -2, -3). Graphs corresponding to the same parameters (weight, height, and BMI) showing the main z scores across all ages from 5 to 18 years are illustrated. Conclusion: This report provides the first reference for nutritional status and growth of Saudi school-age children and adolescents. This tool is essential for more accurate assessment of growth and nutrition in various clinical conditions and research. PMID:27488329

  11. 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

  12. 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. PMID:26635702

  13. Measuring aging rates of mice subjected to caloric restriction and genetic disruption of growth hormone signaling

    PubMed Central

    Koopman, Jacob J.E.; van Heemst, Diana; van Bodegom, David; Bonkowski, Michael S.; Sun, Liou Y.; Bartke, Andrzej

    2016-01-01

    Caloric restriction and genetic disruption of growth hormone signaling have been shown to counteract aging in mice. The effects of these interventions on aging are examined through age-dependent survival or through the increase in age-dependent mortality rates on a logarithmic scale fitted to the Gompertz model. However, these methods have limitations that impede a fully comprehensive disclosure of these effects. Here we examine the effects of these interventions on murine aging through the increase in age-dependent mortality rates on a linear scale without fitting them to a model like the Gompertz model. Whereas these interventions negligibly and non-consistently affected the aging rates when examined through the age-dependent mortality rates on a logarithmic scale, they caused the aging rates to increase at higher ages and to higher levels when examined through the age-dependent mortality rates on a linear scale. These results add to the debate whether these interventions postpone or slow aging and to the understanding of the mechanisms by which they affect aging. Since different methods yield different results, it is worthwhile to compare their results in future research to obtain further insights into the effects of dietary, genetic, and other interventions on the aging of mice and other species. PMID:26959761

  14. The impact of aging on gray matter structural covariance networks.

    PubMed

    Montembeault, Maxime; Joubert, Sven; Doyon, Julien; Carrier, Julie; Gagnon, Jean-François; Monchi, Oury; Lungu, Ovidiu; Belleville, Sylvie; Brambati, Simona Maria

    2012-11-01

    Previous anatomical volumetric studies have shown that healthy aging is associated with gray matter tissue loss in specific cerebral regions. However, these studies may have potentially missed critical elements of age-related brain changes, which largely exist within interrelationships among brain regions. This magnetic resonance imaging research aims to assess the effects of aging on the organization of gray matter structural covariance networks. Here, we used voxel-based morphometry on high-definition brain scans to compare the patterns of gray matter structural covariance networks that sustain different sensorimotor and high-order cognitive functions among young (n=88, mean age=23.5±3.1 years, female/male=55/33) and older (n=88, mean age=67.3±5.9 years, female/male=55/33) participants. This approach relies on the assumption that functionally correlated brain regions show correlations in gray matter volume as a result of mutually trophic influences or common experience-related plasticity. We found reduced structural association in older adults compared with younger adults, specifically in high-order cognitive networks. Major differences were observed in the structural covariance networks that subserve the following: a) the language-related semantic network, b) the executive control network, and c) the default-mode network. Moreover, these cognitive functions are typically altered in the older population. Our results indicate that healthy aging alters the structural organization of cognitive networks, shifting from a more distributed (in young adulthood) to a more localized topological organization in older individuals. PMID:22776455

  15. Growth and aging of proximal femoral bone: a study with women spanning three generations.

    PubMed

    Wang, Qin; Chen, Decai; Cheng, Shu Mei; Nicholson, Patrick; Alen, Markku; Cheng, Sulin

    2015-03-01

    Osteoporotic hip fracture is a serious clinical event associated with high morbidity and mortality. Understanding femoral growth patterns is important for promoting bone health in the young and preventing fractures in later life. In this study, growth patterns of areal bone mineral density (aBMD) and geometric properties of the proximal femur were measured by dual-energy X-ray absorptiometry. They were studied in 251 girls from premenarche (11.2 ± 0.7 years) to late adolescence (18.3 ± 1.1 years) and compared with their premenopausal mothers (n = 128, aged 44.9 ± 4.1 years) and postmenopausal grandmothers (n = 128, aged 70.0 ± 6.3 years). Hip axis length (HAL) was the first to reach peak growth velocity (-10.5 months before menarche), followed by neck diameter (ND) and neck cross-sectional area (CSA), (-7.1 and -4.1 months before menarche, respectively). Both neck-shaft angle (NSA) and aBMD of neck and total hip peaked at menarche. At 18 years (7-year follow-up), girls already had higher femoral neck aBMD but similar HAL and NSA compared with their mothers. Grandmothers had the longest HAL, narrowest NSA, widest ND but lowest aBMD and CSA. Hip strength index (HSI), an index of femoral neck strength during a fall, dropped rapidly after menarche in girls but thereafter remained relatively constant. Grandmothers had lower HSI than either mothers or girls. In conclusion, differences in proximal femoral bone mass and structure in adulthood are largely established before menarche, indicating that heritable factors are responsible for most of the individual variance. The development of geometric properties precedes aBMD in puberty, resulting in relatively constant hip strength after menarche. This asynchronous growth leads to adaptation of bone strength to the imposed loads, avoiding fractures in a biologically efficient manner. Both deterioration of aBMD and inadequate compensatory change in bone geometry after menopause contribute to the

  16. Structural brain changes in aging: courses, causes and cognitive consequences.

    PubMed

    Fjell, Anders M; Walhovd, Kristine B

    2010-01-01

    The structure of the brain is constantly changing from birth throughout the lifetime, meaning that normal aging, free from dementia, is associated with structural brain changes. This paper reviews recent evidence from magnetic resonance imaging (MRI) studies about age-related changes in the brain. The main conclusions are that (1) the brain shrinks in volume and the ventricular system expands in healthy aging. However, the pattern of changes is highly heterogeneous, with the largest changes seen in the frontal and temporal cortex, and in the putamen, thalamus, and accumbens. With modern approaches to analysis of MRI data, changes in cortical thickness and subcortical volume can be tracked over periods as short as one year, with annual reductions of between 0.5% and 1.0% in most brain areas. (2) The volumetric brain reductions in healthy aging are likely only to a minor extent related to neuronal loss. Rather, shrinkage of neurons, reductions of synaptic spines, and lower numbers of synapses probably account for the reductions in grey matter. In addition, the length of myelinated axons is greatly reduced, up to almost 50%. (3) Reductions in specific cognitive abilities--for instance processing speed, executive functions, and episodic memory--are seen in healthy aging. Such reductions are to a substantial degree mediated by neuroanatomical changes, meaning that between 25% and 100% of the differences between young and old participants in selected cognitive functions can be explained by group differences in structural brain characteristics. PMID:20879692

  17. Age and growth of lake sturgeon in the upper St. Lawrence River

    USGS Publications Warehouse

    Johnson, J.H.; Dropkin, D.S.; LaPan, S.R.; McKenna, J.E., Jr.; Klindt, R.M.

    1998-01-01

    The growth of lake sturgeon (Acipenser fulvescens) over time in the upper St. Lawrence River was examined. Growth of lake sturgeon collected during 1993 and 1994 below Robert Moses Dam near Massena, New York, was compared to that reported for the same population almost 25 years earlier. The data suggest that lake sturgeon growth was similar to that reported in the previous study. However, significant differences in the elevations of regression models between males and fish of unknown sex in both data sets suggest possible sexual dimorphism in growth at younger ages.

  18. Processing of temporal fine structure as a function of age

    PubMed Central

    Grose, John H.; Mamo, Sara K.

    2010-01-01

    Objectives The purpose of this study was to determine whether the processing of temporal fine structure diminishes with age, even in the presence of relatively normal audiometric hearing. Temporal fine structure processing was assessed by measuring the discrimination of inter-aural phase differences (IPDs). The hypothesis was that IPD discrimination is more acute in middle-aged observers than in older observers but that acuity in middle-aged observers is nevertheless poorer than in young adults. Design Two experiments were undertaken. The first measured discrimination of 0-and π-radian inter-aural phases as a function of carrier frequency. The stimulus was a 5-Hz sinusoidally amplitude modulated tone where, in the signal waveform, the inter-aural phase of the carrier was inverted during alternate modulation periods. The second experiment measured IPD discrimination at fixed frequencies. The stimulus was a pair of tone pulses where, in the signal, the trailing pulse contained an IPD. A total of 39 adults with normal audiograms below 2000 Hz participated: 15 younger, 12 middle-aged, and 12 older. Results Experiment 1 showed that the highest carrier frequency at which a π-radian IPD could be discriminated from the diotic, 0-radian standard was significantly lower in middle-aged listeners than young adults, and lower still in older listeners. Experiment 2 indicated that middle-aged listeners were less sensitive to IPDs than young adults at all but the lowest frequencies tested. Older listeners, as a group, had the poorest thresholds. Conclusions These results suggest that deficits in temporal fine structure processing are evident in the pre-senescent auditory system. This adds to the accumulating evidence that deficiencies in some aspects of auditory temporal processing emerge relatively early in the aging process. It is possible that early-emerging temporal processing deficits manifest themselves in challenging speech-in-noise environments. PMID:20592614

  19. [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. PMID:25898607

  20. Plant size, not age, regulates growth and gas exchange in grafted Scots pine trees.

    PubMed

    Vanderklein, D; Martínez-Vilalta, J; Lee, S; Mencuccini, M

    2007-01-01

    We studied the effect of scion donor-tree age on the physiology and growth of 6- to 7-year-old grafted Scots pine (Pinus sylvestris L.) trees (4 and 5 years after grafting). Physiological measurements included photosynthethetic rate, stomatal conductance, transpiration, whole plant hydraulic conductance, needle nitrogen concentration and carbon isotope composition. Growth measurements included total and component biomasses, relative growth rates and growth efficiency. Scion donor trees ranged in age from 36 to 269 years at the time of grafting. Hydraulic conductance was measured gravimetrically, applying the Ohm's law analogy, and directly, with a high-pressure flow meter. We found no effect of scion donor-tree age on any of the variables measured. There was, however, great variation within scion donor-tree age groups, which was related to the size of the grafted trees. Differences in size may have been caused by variable initial grafting success, but there was no indication that grafting success and age were related. At the stem level, hydraulic conductance scaled with total leaf area so that total conductance per unit leaf area did not vary with crown size. However, leaf specific hydraulic conductance (gravimetric), transpiration, photosynthesis and stomatal conductance declined with increasing total tree leaf area and needle width. We hypothesize that needle width is inversely related to mesophyll conductance. We conclude that canopy and needle size and not scion donor-tree age determined gas exchange in our grafted trees. PMID:17169908

  1. Efficacy and safety of growth hormone treatment for children born small for gestational age

    PubMed Central

    2014-01-01

    Recombinant growth hormone (GH) is an effective treatment for short children who are born small for gestational age (SGA). Short children born SGA who fail to demonstrate catch-up growth by 2-4 years of age are candidates for GH treatment initiated to achieve catch-up growth to a normal height in early childhood, maintain a normal height gain throughout childhood, and achieve an adult height within the normal target range. GH treatment at a dose of 35-70 µg/kg/day should be considered for those with very marked growth retardation, as these patients require rapid catch-up growth. Factors associated with response to GH treatment during the initial 2-3 years of therapy include age and height standard deviation scores at the start of therapy, midparental height, and GH dose. Adverse events due to GH treatment are no more common in the SGA population than in other conditions treated with GH. Early surveillance in growth clinics is strongly recommended for children born SGA who have not caught up. Although high dose of up to 0.067 mg/kg/day are relatively safe for short children with growth failure, clinicians need to remain aware of long-term mortality and morbidity after GH treatment. PMID:25324863

  2. Growth and structure of pyrogenic silica

    SciTech Connect

    Schaefer, D.W.; Hurd, A.J.; Christen, D.K.; Spooner, S.; Lin, J.S.

    1988-01-01

    Fractal analysis is used to interpret small-angle x-ray and neutron scattering data on commercial fumed silica powders. Rough primary particles are found in high surface area powders. A model based on ballistic polymerization, sintering, and diffusion-limited aggregation is proposed to explain the observed powder structure. 13 refs., 6 figs.

  3. Growth and structure of pyrogenic silica

    SciTech Connect

    Schaefer, D.W.; Hurd, A.J.; Christen, D.K.; Spooner, S.; Lin, J.S.

    1988-06-01

    Fractal analysis is used to interpret small-angle X-ray and neutron scattering data on commercial fund silica powders. Rough primary particles are found in high surface area powders. A model based on ballistic polymerization, sintering, and diffusion-limited aggregation is proposed to explain the observed powder structure. 13 refs., 6 figs.

  4. Aircraft fatigue and crack growth considering loads by structural component

    NASA Technical Reports Server (NTRS)

    Yost, J. D.

    1994-01-01

    The indisputable 1968 C-130 fatigue/crack growth data is reviewed to obtain additional useful information on fatigue and crack growth. The proven Load Environment Model concept derived empirically from F-105D multichannel recorder data is refined to a simpler method by going from 8 to 5 variables in the spectra without a decrease in accuracy. This approach provides the true fatigue/crack growth and load environment by structural component for both fatigue and strength design. Methods are presented for defining fatigue scatter and damage at crack initiation. These design tools and criteria may be used for both metal and composite aircraft structure.

  5. Management of aging of nuclear power plant containment structures

    SciTech Connect

    Naus, D.; Oland, C.B.; Ellingwood, B.; Norris, W.E.; Graves, H.L. III

    1998-06-01

    Research addressing aging management of nuclear power plant concrete and steel containment structures is summarized. Accomplishments related to concrete containment structures include formation of a materials` property database; an aging assessment methodology to identify critical structures and degradation factors; guidelines and evaluation criteria for use in condition assessments; and a time-dependent reliability-based methodology for condition assessments and estimations of future performance. Under the steel containments and liners activity, a degradation assessment methodology has been developed, mathematical models that describe time-dependent changes in the containment due to aggressive environmental factors have been identified, and statistical data supporting the use of these models in time-dependent reliability analysis have been summarized.

  6. Composite growth model applied to human oral and pharyngeal structures and identifying the contribution of growth types.

    PubMed

    Wang, Yuan; Chung, Moo K; Vorperian, Houri K

    2013-11-13

    The growth patterns of different anatomic structures in the human body vary in terms of growth amount over time, growth rate and growth periods. The oral and pharyngeal structures, also known as vocal tract structures, are housed in the craniofacial complex where the cranium/brain follows a distinct neural growth pattern, and the face follows a distinct somatic or skeletal growth pattern. Thus, it is reasonable to expect the oral and pharyngeal structures to follow a combined or mixed growth pattern. Existing parametric growth models are limited in that they are mainly focused on modeling one particular type of growth pattern. In this paper, we propose a novel composite growth model using neural and somatic baseline curves to fit the combined growth pattern of select vocal tract structures. The method can also determine the overall percent contribution of each of the growth types. PMID:24226094

  7. Composite Growth Model Applied to Human Oral and Pharyngeal Structures and Identifying the Contribution of Growth Types

    PubMed Central

    Wang, Yuan; Chung, Moo K.; Vorperian, Houri K.

    2014-01-01

    The growth patterns of different anatomic structures in the human body vary in terms of growth amount over time, growth rate and growth periods. The oral and pharyngeal structures, also known as vocal tract structures, are housed in the craniofacial complex where the cranium/brain follows a distinct neural growth pattern, and the face follows a distinct somatic or skeletal growth pattern. Thus, it is reasonable to expect the oral and pharyngeal structures to follow a combined or mixed growth pattern. Existing parametric growth models are limited in that they are mainly focused on modeling one particular type of growth pattern. In this paper, we propose a novel composite growth model using neural and somatic baseline curves to fit the combined growth pattern of select vocal tract structures. The method can also determine the overall percent contribution of each of the growth types. PMID:24226094

  8. Pore network microarchitecture influences human cortical bone elasticity during growth and aging.

    PubMed

    Bala, Yohann; Lefèvre, Emmanuelle; Roux, Jean-Paul; Baron, Cécile; Lasaygues, Philippe; Pithioux, Martine; Kaftandjian, Valérie; Follet, Hélène

    2016-10-01

    Cortical porosity is a major determinant of bone strength. Haversian and Volkmann׳s canals are׳seen' as pores in 2D cross-section but fashion a dynamic network of interconnected channels in 3D, a quantifiable footprint of intracortical remodeling. Given the changes in bone remodeling across life, we hypothesized that the 3D microarchitecture of the cortical pore network influences its stiffness during growth and ageing. Cubes of cortical bone of 2 mm side-length were harvested in the distal 1/3 of the fibula in 13 growing children (mean age±SD: 13±4 yrs) and 16 adults (age: 75±13 yrs). The cubes were imaged using desktop micro-CT (8.14µm isotropic voxel size). Pores were segmented as a solid to assess pore volume fraction, number, diameter, separation, connectivity and structure model index. Elastic coefficients were derived from measurements of ultrasonic bulk compression and shear wave velocities and apparent mass density. The pore volume fraction did not significantly differ between children and adults but originates from different microarchitectural patterns. Compared to children, adults had 42% (p=0.033) higher pore number that were more connected (Connective Density: +205%, p=0.001) with a 18% (p=0.007) lower pore separation. After accounting for the contribution of pore volume fraction, axial elasticity in traction-compression mode was significantly correlated with better connectivity in growing children and with pore separation among adults. The changes in intracortical remodeling across life alter the distribution, size and connectedness of the channels from which cortical void fraction originates. These alterations in pore network microarchitecture participate in changes in compressive and shear mechanical behavior, partly in a porosity-independent manner. The assessment of pore volume fraction (i.e., porosity) provides only a limited understanding of the role of cortical void volume fraction in its mechanical properties. PMID:27389322

  9. Grain growth and structural relaxation of nanocrystalline Bi₂Te₃

    SciTech Connect

    Humphry-Baker, Samuel A.; Schuh, Christopher A.

    2014-10-21

    Recovery and grain growth behavior is investigated systematically for the nanocrystalline thermoelectric compound bismuth telluride, synthesized by mechanical alloying. During annealing treatments at elevated temperatures, structural evolution is tracked using x-ray diffraction, electron microscopy and calorimetry. Below a homologous temperature of about 0.6T{sub m}, grain growth occurs slowly with an activation energy of 89 kJ/mol. However above this temperature grain growth becomes more rampant with an activation energy of 242 kJ/mol. The transition is attributed to a shift from a relaxation or recovery process that includes some reordering of the grain boundary structure, to a more conventional diffusionally-limited grain growth process. By extrapolating the measured grain growth and microstrain evolution kinetics, a thermal budget map is constructed, permitting recommendations for improving the thermoelectric properties of nanocrystalline materials processed via a powder route.

  10. 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.

  11. Age Determination and Growth Rates in Deep-Water Bamboo Corals (Isididae)

    NASA Astrophysics Data System (ADS)

    Fallon, S. J.; Thresher, R.; Sherwood, O.

    2009-12-01

    Gorgonians are a major element of the fauna of deep-water coral reefs and very long-lived recorders of deep-water paleo-oceanography. Both ecological studies and paleo-analyses require accurate age determination and dating of colony formation, but because of the depths at which they occur (typically 1-3 km), direct validation by tagging of aging methods is logistically difficult. Radiocarbon analysis of both the node organic tissue and internode calcite provided apparently robust age and date information. Growth rates ranged from 40 to ~140 microns per year in samples collected from 600 to 1600m water depth. Following these analyses, we compiled the robust growth-rate data for recent material, and report on a first-pass analysis of ecological and regional effects on isidid growth rates.

  12. Crystal Structure of Patatin-17 in Complex with Aged and Non-Aged Organophosphorus Compounds

    PubMed Central

    Wijeyesakere, Sanjeeva J.; Richardson, Rudy J.; Stuckey, Jeanne A.

    2014-01-01

    Patatin is a non-specific plant lipase and the eponymous member of a broad class of serine hydrolases termed the patatin-like phospholipase domain containing proteins (PNPLAs). Certain PNPLA family members can be inhibited by organophosphorus (OP) compounds. Currently, no structural data are available on the modes of interaction between the PNPLAs and OP compounds or their native substrates. To this end, we present the crystal structure of patatin-17 (pat17) in its native state as well as following inhibition with methyl arachidonyl fluorophosphonate (MAFP) and inhibition/aging with diisopropylphosphorofluoridate (DFP). The native pat17 structure revealed the existence of two portals (portal1 and portal2) that lead to its active-site chamber. The DFP-inhibited enzyme underwent the aging process with the negatively charged phosphoryl oxygen, resulting from the loss of an isopropyl group, being within hydrogen-binding distance to the oxyanion hole. The MAFP-inhibited pat17 structure showed that MAFP did not age following its interaction with the nucleophilic serine residue (Ser77) of pat17 since its O-methyl group was intact. The MAFP moiety is oriented with its phosphoryl oxygen in close proximity to the oxyanion hole of pat17 and its O-methyl group located farther away from the oxyanion hole of pat17 relative to the DFP-bound state. The orientation of the alkoxy oxygens within the two OP compounds suggests a role for the oxyanion hole in stabilizing the emerging negative charge on the oxygen during the aging reaction. The arachidonic acid side chain of MAFP could be contained within portals 1 or 2. Comparisons of pat17 in the native, inhibited, and aged states showed no significant global conformational changes with respect to their Cα backbones, consistent with observations from other α/β hydrolases such as group VIIA phospholipase A2. PMID:25248161

  13. Statistical method for detecting structural change in the growth process.

    PubMed

    Ninomiya, Yoshiyuki; Yoshimoto, Atsushi

    2008-03-01

    Due to competition among individual trees and other exogenous factors that change the growth environment, each tree grows following its own growth trend with some structural changes in growth over time. In the present article, a new method is proposed to detect a structural change in the growth process. We formulate the method as a simple statistical test for signal detection without constructing any specific model for the structural change. To evaluate the p-value of the test, the tube method is developed because the regular distribution theory is insufficient. Using two sets of tree diameter growth data sampled from planted forest stands of Cryptomeria japonica in Japan, we conduct an analysis of identifying the effect of thinning on the growth process as a structural change. Our results demonstrate that the proposed method is useful to identify the structural change caused by thinning. We also provide the properties of the method in terms of the size and power of the test. PMID:17608782

  14. 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.

  15. Nerve growth factor signaling following unilateral pelvic ganglionectomy in the rat ventral prostate is age dependent.

    PubMed

    Podlasek, Carol A; Ghosh, Rudrani; Onur Cakir, Omer; Bond, Christopher; McKenna, Kevin E; McVary, Kevin T

    2013-11-01

    Benign prostatic hyperplasia (BPH) is a serious health concern and is an underlying cause of lower urinary tract symptoms (LUTS) in many men. In affected men, LUTS/BPH is believed to result from benign proliferation of the prostate resulting in bladder outlet obstruction. Postnatal growth of the prostate is controlled via growth factor and endocrine mechanisms. However, little attention had been given to the function of the autonomic nervous system in prostate growth and differentiation. Nerve growth factor (NGF) is a prostatic mitogen that has a trophic role in autonomic sensory end organ interaction. In this study, we examine how the autonomic nervous system influences prostate growth as a function of age by quantifying NGF in the rat ventral prostate (VP) after pelvic ganglionectomy. Unilateral pelvic ganglionectomy was performed on postnatal days 30 (P30), 60 and 120 Sprague-Dawley rats in comparison to sham controls (n=39). Semiquantitative RT-PCR, Western blotting and immunohistochemical analysis for NGF were performed on denervated, intact (contralateral side) and sham control VP 7 days after surgery. Ngf RNA expression was significantly increased in the denervated and intact hyperplastic VP. Western blotting showed age-dependent increases in NGF protein at P60 in the contralateral intact VP. NGF was localized in the nerves, basal cells and columnar epithelium of the prostatic ducts. Denervation causes age-dependent increases in NGF in the VP, which is a potential mechanism by which the autonomic nervous system may regulate prostate growth and lead to BPH/LUTS. PMID:23872662

  16. 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.

  17. 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.

  18. 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

  19. Age, growth, sexual maturity, and food of channel catfish in central Lake Oahe, 1968-69

    USGS Publications Warehouse

    Starostka, Victor J.; Nelson, William R.

    1974-01-01

    Channel catfish, Ictalurus punctatus, were collected with gill nets, trawl, and trap nets at three localities in Lake Oahe for the study of year-class strength, growth in length and weight, age composition, sexual maturity, and food. Fish were recruited to all the collection gears at age II. Relatively strong year classes were produced in 1962, 1965, and 1966. Youngest fish were captured in the upper end of the Moreau River embayment, which apparently serves as a nursery area. Growth of age 0 fish was poor probably because the growing season was short; optimum spawning temperature were not reached until mid-summer. Growth of age II and older fish reached a peak in 1963 and declined rather steadily in 1964-68. Males began to mature at age VIII, and all fish of both sexes were mature at age XI. The diet changed from zooplankton to fish as channel catfish increased in length; aquatic insects (primarily chironomid larvae and pupae) were important foods for fish of all sizes. Fish less than 300 mm long selected large zooplankters -- Leptodora kindtii and Daphnia spp -- over smaller copepods. Larger channel catfish ate principally yellow perch, Perca flavescens.

  20. Age, growth, mortality, and abundance of lake sturgeon in the Grasse River, New York, USA

    USGS Publications Warehouse

    Trested, D.G.; Isely, J.J.

    2011-01-01

    An increased understanding of lake sturgeon (Acipenser fulvescens) population dynamics is a key requirement for successful management efforts. Little is known regarding the Grasse River population of lake sturgeon except that it is one of a few populations in New York State where spawning has been documented. Thus our purpose was to assess the current status of lake sturgeon in the Grasse River system, including age, growth, mortality, and abundance. Age was determined for 196 of 211 lake sturgeon by examination of sectioned pectoral fin rays. Ages ranged from 0 to 32 years and the annual mortality rate for fish between ages 7 and 14 was 16.8%. The weight (W, g) to total length (TL, mm) relationship was W = 1.281 x 10-6TL3.202. The von Bertalanffy growth equation was TL = 1913(1-e-0.0294(t+9.5691)). While the range of observed ages was similar to that of nearby St. Lawrence River populations, mean weight at age for an individual at 1000 mm TL was lower than that observed for lake sturgeon within Lake St. Francis of the St. Lawrence River. Predicted growth based on von Bertalanffy parameters was similar to that observed for the nearby Lake St. Francis. An open population estimator using the POPAN sub-module in the Program MARK produced an abundance estimate of 793 lake sturgeon (95% CI = 337-1249).

  1. The growth of structures - Building clusters

    NASA Astrophysics Data System (ADS)

    Arnaud, M.

    Clusters of galaxies are the largest and most massive collapsed objects in the Universe. In the standard cosmological scenario, they form from the collapse of initial density fluctuations that grow under the influence of gravity, following recurrent merging events. Clusters of galaxies are still forming at the present epoch and the observation of this evolving population provides unique constraints on the physics that governs large scale structure formation and evolution. The presence of substructure in present epoch clusters give clear support to the hierarchical scenario. More recently, detailed gas temperature maps obtained with XMM and Chandra, and the discovery of cold fronts, provide unambiguous evidence of ongoing mergers. The substructures in clusters contain of fossil record of the merger history. Thus, statistical studies of the cluster morphology can provide important test of cosmological models of structure formation. However, data from a single epoch cannot unambiguously disentangle the merging history of clusters. The available data clearly show that the physics of merger events is a particularly complex process, which remains poorly understood, in particular the survival time of merger substructures. In the hierarchical merging scenario, clusters are expected to constitute a homologous family. We do see regularity in the local cluster population - strong correlations between the various properties, like the luminosity, mass, temperature, velocity dispersion, evidence for universal density and temperature profile for hot clusters. However, it is now well established that a purely gravitational scenario fails to explain all the observed properties of clusters. For instance, the luminosity-temperature relation is steeper than expected and an entropy excess is observed in the core of cool systems. Recent XMM data suggest that this entropy floor has been established at high redshift. However, the physical origin of this break of self-similarity remains

  2. [Esophageal wall structure in people of elderly and senile age].

    PubMed

    aminova, G G; Grigorenko, D E; Sapin, M R; Mkhitarov, V A

    2014-01-01

    Using histological methods, the esophageal wall structure and the cytoarchitectonics of mucous membrane were studied in the individuals of elderly (n = 5) and senile (n = 10) age. The control group included the individuals of I (n = 3) and II (n = 3) periods of mature age. It was demonstrated that with advancing age in most cases the destructive processes took place in the epithelium (delamination of the layer, separation of large fragments, formation of microerosions etc.) in most of the studied cases. Lymphocytes, neutrophils and eosinophils were found between the epithelial cells; the numbers of infiltrating cells was increased 2-3 times during aging. Mucosal lamina propria and the submucosa, in particular, were characterized by the thickening of the bundles of collagen fibers. A two-fold increase in the number of the cells of the fibroblast lineage was found. The number of leukocytes in the lamina propria was increased by the eldery age in the upper and lower parts of the esophagus (3.5 and 1.75 times respectively). The changes in lamina muscularis were manifested by its thinning, delamination and myocyte dissociation. Remodeling of the muscular tunic was less pronounced. The degree of changes increased distally and varied widely depending on the individual peculiarities. PMID:25282822

  3. The Umm Al Binni Structure and Bronze Age Catastrophes

    NASA Astrophysics Data System (ADS)

    Hamacher, Duane W.

    Archaeological excavations of sites dating from 2200 BCE and 1200 BCE in the Middle East, Asia Minor, and southeast Europe provide evidence that a large scale disaster affected Bronze Age civilizations. There are numerous debates as to whether this was caused by warfare, a large-scale natural disaster, or some other factor. In 2001, Sharad Master used satellite images to discover a possible Holocene impact structure in the Al 'Amarah marshes of southern Iraq, known as Umm al Binni lake. With an estimated age of < 5000 years and a diameter of ~3.4 km, this structure may help explain this disaster. Using numerical models and scaling equations for a cosmic impact, I show that although destructive forces would have damaged Sumerian cities within a few hundred km of the coast, it is unlikely that this single impact would have caused the large-scale destruction seen over the larger region. The impact origin of the structure is unconfirmed and any connection to Bronze Age catastrophes remains speculative. Errata: Table 4 provides a list of impact sites, three of which are associated with nickel-iron impactors and therefore cannot be from a "fragmented comet".

  4. Nucleation and structural growth of cluster crystals.

    PubMed

    Leitold, Christian; Dellago, Christoph

    2016-08-21

    We study the nucleation of crystalline cluster phases in the generalized exponential model with exponent n = 4. Due to the finite value of this pair potential for zero separation, at high densities the system forms cluster crystals with multiply occupied lattice sites. Here, we investigate the microscopic mechanisms that lead to the formation of cluster crystals from a supercooled liquid in the low-temperature region of the phase diagram. Using molecular dynamics and umbrella sampling, we calculate the free energy as a function of the size of the largest crystalline nucleus in the system, and compare our results with predictions from classical nucleation theory. Employing bond-order parameters based on a Voronoi tessellation to distinguish different crystal structures, we analyze the average composition of crystalline nuclei. We find that even for conditions where a multiply occupied fcc crystal is the thermodynamically stable phase, the nucleation into bcc cluster crystals is strongly preferred. Furthermore, we study the particle mobility in the supercooled liquid and in the cluster crystal. In the cluster crystal, the motion of individual particles is captured by a simple reaction-diffusion model introduced previously to model the kinetics of hydrogen bonds. PMID:27544116

  5. Creep crack growth behavior of several structural alloys

    NASA Astrophysics Data System (ADS)

    Sadananda, K.; Shahinian, P.

    1983-07-01

    Creep crack growth behavior of several high temperature alloys, Inconel 600, Inconel 625, Inconel X-750, Hastelloy X, Nimonic PE-16, Incoloy 800, and Haynes 25 (HS-25) was examined at 540, 650, 760, and 870 °C. Crack growth rates were analyzed in terms of both linear elastic stress intensity factor and J*-integral parameter. Among the alloys Inconel 600 and Hastelloy X did not show any observable crack growth. Instead, they deformed at a rapid rate resulting in severe blunting of the crack tip. The other alloys, Inconel 625, Inconel X-750, Incoloy 800, HS-25, and PE-16 showed crack growth at one or two temperatures and deformed continuously at other temperatures. Crack growth rates of the above alloys in terms ofJ* parameter were compared with the growth rates of other alloys published in the literature. Alloys such as Inconel X-750, Alloy 718, and IN-100 show very high growth rates as a result of their sensitivity to an air environment. Based on detailed fracture surface analysis, it is proposed that creep crack growth occurs by the nucleation and growth of wedge-type cracks at triple point junctions due to grain boundary sliding or by the formation and growth of cavities at the boundaries. Crack growth in the above alloys occurs only in some critical range of strain rates or temperatures. Since the service conditions for these alloys usually fall within this critical range, knowledge and understanding of creep crack growth behavior of the structural alloys are important.

  6. Maternal Smoking During Pregnancy and Growth in Infancy: a Covariance Structure Analysis

    PubMed Central

    Zheng, Wei; Suzuki, Kohta; Shinohara, Ryoji; Sato, Miri; Yokomichi, Hiroshi; Yamagata, Zentaro

    2015-01-01

    Background Smoking during pregnancy is related to fetal constraint and accelerated postnatal growth. However, the pathways between these factors have not been clarified. Pathway analyses that link these factors can help us better understand the mechanisms involved in this association. Therefore, this study aimed to examine pathways between maternal smoking during pregnancy and growth in infancy. Methods Participants were singletons born between 1993 and 2006 in rural Japan. The outcome was the change in weight z-score between birth and 3 years of age. Pathways from maternal smoking and other maternal factors (such as maternal body mass index and work status) to growth in infancy via birth factors (such as birth weight and gestational age) and breastfeeding were examined using structural equation modeling. Results Complete data were available for 1524 children (775 boys and 749 girls). The model fit appeared adequate. Lower birth weight and non-exclusive breastfeeding mediated the association between maternal smoking during pregnancy and rapid growth in infancy. Maternal smoking was also directly linked to rapid growth in infancy (standardized direct effects 0.06, P = 0.002). Taking all pathways into account, the standardized total effect of maternal smoking on growth in infancy was 0.11. Conclusions Maternal smoking during pregnancy may both indirectly, through birth weight and breastfeeding status, and directly influence growth during infancy; however, there may be other pathways that have not yet been identified. PMID:25327186

  7. 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.

  8. Differential Effects of Intelligence, Perceptual Speed and Age on Growth in Attentional Speed and Accuracy

    ERIC Educational Resources Information Center

    Goldhammer, Frank; Rauch, Wolfgang A.; Schweizer, Karl; Moosbrugger, Helfried

    2010-01-01

    The study investigates the effects of intelligence, perceptual speed and age on intraindividual growth in attentional speed and attentional accuracy over the course of a 6-minute testing session. A sample of 193 subjects completed the Advanced Progressive Matrices and the Vienna Matrices Test representing intelligence, the tests Alertness and…

  9. 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 ...

  10. Growth of the Tongariro volcanic complex: New evidence from K-Ar age determinations

    USGS Publications Warehouse

    Hobden, B.J.; Houghton, B.F.; Lanphere, M.A.; Nairn, I.A.

    1996-01-01

    New K-Ar age determinations indicate that the exposed portion of the Tongariro volcanic complex has grown steadily since at least 275 ka, with intervals of vigorous cone growth at 210-200.130-70. and 25 ka to the present day.

  11. Perceptual Information for the Age Level of Faces as a Higher Order Invariant of Growth.

    ERIC Educational Resources Information Center

    Pittenger, John B.; And Others

    1979-01-01

    Previous work supports the hypothesis that cardioidal strain offers a plausible mathematical model for the perceived changes in human craniofacial morphology due to growth. In two experiments, cardioidal strain caused changes in the perceived age of nonhuman profiles similar to those produced on human faces in earlier work. (Author/MH)

  12. The effect of growth rate, diameter and impurity concentration on structure in Czochralski silicon crystal growth

    NASA Technical Reports Server (NTRS)

    Digges, T. G., Jr.; Shima, R.

    1980-01-01

    It is demonstrated that maximum growth rates of up to 80% of the theoretical limit can be attained in Czochralski-grown silicon crystals while maintaining single crystal structure. Attaining the other 20% increase is dependent on design changes in the grower, to reduce the temperature gradient in the liquid while increasing the gradient in the solid. The conclusions of Hopkins et al. (1977) on the effect of diameter on the breakdown of structure at fast growth rates are substantiated. Copper was utilized as the test impurity. At large diameters (greater than 7.5 cm), concentrations of greater than 1 ppm copper were attained in the solid (45,000 ppm in the liquid) without breakdown at maximum growth speeds. For smaller diameter crystals, the sensitivity of impurities is much more apparent. For solar cell applications, impurities will limit cell performance before they cause crystal breakdown for fast growth rates of large diameter crystals.

  13. Age and growth of mangrove red snapper Lutjanus argentimaculatus at its cool-water-range limits.

    PubMed

    Piddocke, T P; Butler, G L; Butcher, P A; Stewart, J; Bucher, D J; Christidis, L

    2015-05-01

    This study investigates the age and growth of Lutjanus argentimaculatus at its southern (cooler) range limits in eastern Australia. Specimens were collected from New South Wales and southern Queensland between November 2011 and December 2013. Fork lengths (LF ) ranged from 190 to 1019 mm, and ages ranged from 2+ to 57+ years. Growth was described by the von Bertalanffy growth function with coefficients L∞ = 874·92 mm, K = 0·087 year(-1) and t0 = -2·76 years. Estimates of the instantaneous natural mortality rate (M) ranged from 0·072 to 0·25. The LF (mm) and mass (W; g) relationship was represented by the equation: W=2·647×10-5LF2·92. The maximum age of 57+ years is the oldest reported for any lutjanid and comparisons with tropical studies suggest that the age-based demography of L. argentimaculatus follows a latitudinal gradient. High maximum ages and low natural mortality rates indicate considerable vulnerability to overexploitation at the species' cool-water-range limits. These results demonstrate the need to identify underlying processes driving latitudinal gradients in fish demography. PMID:25943148

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

    SciTech Connect

    Roark, E B; Guilderson, T P; Flood-Page, S; Dunbar, R B; Ingram, B L; Fallon, S J; McCulloch, M

    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 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.

  15. 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).

  16. 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

  17. 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

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

    PubMed Central

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

    2015-01-01

    ABSTRACT Introduction: 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. Materials and methods: 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. Results: 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. Conclusion: 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. PMID:26628853

  19. Impact of age on epidermal growth factor receptor mutation in lung cancer.

    PubMed

    Ueno, Tsuyoshi; Toyooka, Shinichi; Suda, Kenichi; Soh, Junichi; Yatabe, Yasushi; Miyoshi, Shinichiro; Matsuo, Keitaro; Mitsudomi, Tetsuya

    2012-12-01

    Aging is one of the best, but rarely referred, risk factors for various types of cancer including lung cancer, because age could be a surrogate for accumulation of genetic events in cancers. Smoking inversely associates with the presence of epidermal growth factor receptor (EGFR) mutation in lung cancer, but its strong confounding with age and sex makes it difficult to evaluate sole impact of age. To clarify an impact of age on EGFR mutation, we conducted a cross-sectional study based on data of 1262 lung cancer patients. The associations between EGFR mutation and age, considering sex, smoking and histology, were evaluated using logistic regression models. In multivariate analysis, we found a significant increase of EGFR mutation prevalence by increase of age (p-trend=0.0004). Consistent trend was observed among never-smoking females (p-trend=0.011) and never-smoking males also showed similar trend although not significant. These were consistently observed when we limit the subject to those with adenocarcinoma. In conclusion, age independently associates with EGFR mutation among lung cancer. Positive association between EGFR mutation and age among never-smokers regardless of sex might indicate that EGFR mutation occurs cumulatively by unidentified internal/external factors other than smoking. PMID:23036155

  20. Growth mechanisms, polytypism, and real structure of kaolinite microcrystals

    NASA Astrophysics Data System (ADS)

    Samotoin, N. D.

    2008-09-01

    The mechanisms of growth of kaolinite microcrystals (0.1 5.0 μm 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 in 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 ˜109 cm-2. Layered stepped kaolinite growth pyramids for all mechanisms of growth on the (001) face of kaolinite exhibit the main features of the triclinic 1 Tc and real structures of this mineral.

  1. Growth mechanisms, polytypism, and real structure of kaolinite microcrystals

    SciTech Connect

    Samotoin, N. D.

    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 in 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.

  2. Reconciling CMB and structure growth measurements with dark energy interactions

    NASA Astrophysics Data System (ADS)

    Pourtsidou, Alkistis; Tram, Thomas

    2016-08-01

    We study a coupled quintessence model with pure momentum exchange and present the effects of such an interaction on the cosmic microwave background (CMB) and matter power spectrum. For a wide range of negative values of the coupling parameter β structure growth is suppressed and the model can reconcile the tension between cosmic microwave background observations and structure growth inferred from cluster counts. We find that this model is as good as Λ CDM for CMB and baryon acoustic oscillation data, while the addition of cluster data makes the model strongly preferred, improving the best-fit χ2 value by more than 16.

  3. 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, S.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.

  4. Growth status of small for gestational age Indian children from two socioeconomic strata

    PubMed Central

    Khadilkar, Vaman V.; Mandlik, Rubina M.; Palande, Sonal A.; Pandit, Deepa S.; Chawla, Meghna; Nadar, Ruchi; Chiplonkar, Shashi A.; Kadam, Sandeep S.; Khadilkar, Anuradha A.

    2016-01-01

    Aims: To assess growth and factors associated with growth in children born small for gestational age (SGA) from two socioeconomic strata in comparison to age- and sex-matched healthy controls. Methods: Retrospective study conducted at two hospitals in Pune, 0.5–5 years, 618 children: 189-SGA from upper socioeconomic strata (USS), 217-SGA from lower socioeconomic strata (LSS), and 212 appropriate for gestational age healthy controls were randomly selected. Birth and maternal history, socioeconomic status, length/height, and weight of children were recorded. Anthropometric data were converted to Z scores (height for age Z-score [HAZ], weight for age Z-score [WAZ]) using WHO AnthroPlus software. Results: The HAZ and WAZ of the SGA group were significantly lower as compared to the controls and that of the LSS SGAs were lower than USS SGAs (P < 0.05). Thirty two percent children were stunted (HAZ <−2.0) in USS and 49% in LSS (P < 0.05). Twenty nine percent children in the USS SGA group were stunted at 2 years and 17% at 5 years. In the LSS SGA group, 54% children were stunted at 2 years and 46% at 5 years. Generalized linear model revealed normal vaginal delivery (β = 0.625) and mother's age (β =0.072) were positively associated and high SES (β = −0.830), absence of major illness (β = −1.01), higher birth weight (β = −1.34) were negatively associated for risk of stunting (P < 0.05). Conclusion: Children born SGA showed poor growth as compared to controls. Special attention to growth is necessary in children from LSS, very low birth weight babies, and those with major illnesses during early years of life. PMID:27366721

  5. Active sensors for health monitoring of aging aerospace structures

    SciTech Connect

    GIURGIUTIU,VICTOR; REDMOND,JAMES M.; ROACH,DENNIS P.; RACKOW,KIRK A.

    2000-03-08

    A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (NM) impedance technique are sighted and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high-frequency EIM impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acoustic-ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens representative of aging aerospace structures is presented. Three built-up specimens, (pristine, with cracks, and with corrosion damage) are used. The specimen instrumentation with active sensors fabricated at the University of South Carolina is illustrated. Preliminary results obtained with the E/M impedance method on pristine and cracked specimens are presented.

  6. Active sensors for health monitoring of aging aerospace structures

    SciTech Connect

    GIURGIUTIU,VICTOR; REDMOND,JAMES M.; ROACH,DENNIS P.; RACKOW,KIRK A.

    2000-02-29

    A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (E/M) impedance technique are cited and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high-frequency E/M impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acousto-ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens representative of aging aerospace structures is presented. Three built-up specimens (pristine, with cracks, and with corrosion damage) are used. The specimen instrumentation with active sensors fabricated at the University of South Carolina is illustrated. Preliminary results obtained with the E/M impedance method on pristine and cracked specimens are presented.

  7. Active sensors for health monitoring of aging aerospace structures

    NASA Astrophysics Data System (ADS)

    Giurgiutiu, Victor; Redmond, James M.; Roach, Dennis P.; Rackow, Kirk

    2000-06-01

    A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (E/M) impedance technique are cited and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high frequency E/M impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acousto- ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens representative of aging aerospace structures is presented. Three built-up specimens, (pristine, with cracks, and with corrosion damage) are used. The specimen instrumentation with active sensors fabricated at the University of South Carolina is illustrated. Preliminary results obtained with the E/M impedance method on pristine and cracked specimens are presented.

  8. 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

  9. Definitions of fitness in age-structured populations: Comparison in the haploid case.

    PubMed

    Lessard, Sabin; Soares, Cintia

    2016-02-21

    Fisher's (1930) Fundamental Theorem of Natural Selection (FTNS), and in particular the development of an explicit age-structured version of the theorem, is of everlasting interest. In a recent paper, Grafen (2015a) argues that Fisher regarded his theorem as justifying individual rather than population fitness maximization. The argument relies on a new definition of fitness in age-structured populations in terms of individual birth and death rates and age-specific reproductive values in agreement with a principle of neutrality. The latter are frequency-dependent and defined without reference to genetic variation. In the same paper, it is shown that the rate of increase in the mean of the breeding values of fitness weighted by the reproductive values, but keeping the breeding values constant as in Price (1972) is equal to the additive genetic variance in fitness. Therefore, this partial change is obtained by keeping constant not only the genotypic birth and death rates but also the mean age-specific birth and death rates from which the age-specific reproductive values are defined. In this paper we reaffirm that the Malthusian parameter which measures the relative rate of increase or decrease in reproductive value of each genotype in a continuous-time age-structured population is the definition of fitness used in Fisher's (1930) FTNS. This is shown by considering an age-structured asexual haploid population with constant age-specific birth and death (or survival) parameters for each type. Although the original statement of the FTNS is for a diploid population, this simplified haploid model allows us to address the definition of fitness meant in this theorem without the complexities and effects of a changing genic environment. In this simplified framework, the rate of change in mean fitness in continuous time is expected to be exactly equal to the genetic variance in fitness (or to the genetic variance in fitness divided by the mean fitness in discrete time), which can

  10. Age structure of owned dogs under compulsory culling in a visceral leishmaniasis endemic area.

    PubMed

    Bortoletto, Danielly Vieira; Utsunomiya, Yuri Tani; Perri, Silvia Helena Venturoli; Ferreira, Fernando; Nunes, Cáris Maroni

    2016-01-01

    The age structure of the dog population is essential for planning and evaluating control programs for zoonotic diseases. We analyzed data of an owned-dog census in order to characterize, for the first time, the structure of a dog population under compulsory culling in a visceral leishmaniasis endemic area (Panorama, São Paulo State, Brazil) that recorded a dog-culling rate of 28% in the year of the study. Data on 1,329 households and 1,671 owned dogs revealed an owned dog:human ratio of 1:7. The mean age of dogs was estimated at 1.73 years; the age pyramid indicated high birth and mortality rates at the first year of age with an estimated cumulative mortality of 78% at the third year of age and expected life span of 2.75 years. In spite of the high mortality, a growth projection simulation suggested that the population has potential to grow in a logarithmic scale over the years. The estimated parameters can be further applied in models to maximize the impact and minimize financial inputs of visceral leishmaniasis control measures. PMID:27598014

  11. Benefits of gregarious feeding by aposematic caterpillars depend on group age structure.

    PubMed

    Campbell, Stuart A; Stastny, Michael

    2015-03-01

    Gregarious feeding is a common feature of herbivorous insects and can range from beneficial (e.g. dilution of predation risk) to costly (e.g. competition). Group age structure should influence these costs and benefits, particularly when old and young larvae differ in their feeding mode or apparency to predators. We investigated the relative value of gregarious feeding by aposematic larvae of Uresiphita reversalis that we observed feeding in groups of mixed ages and variable densities on wild Lupinus diffusus. In a manipulative field experiment, the survivorship and growth of young larvae were enhanced in the presence of older conspecifics, but not in large groups of similarly aged larvae. Estimates of insect damage and induced plant responses suggest that mixed-age groups enhance plant quality for young larvae while avoiding competition. We conclude that benefits of gregariousness in this species are contingent on group age structure, a finding of significance for the ecology and evolution of gregariousness and other social behaviours. PMID:25399243

  12. Circulating Growth Differentiation Factor 11/8 Levels Decline With Age

    PubMed Central

    Poggioli, Tommaso; Vujic, Ana; Yang, Peiguo; Macias-Trevino, Claudio; Uygur, Aysu; Loffredo, Francesco S.; Pancoast, James R.; Cho, Miook; Goldstein, Jill; Tandias, Rachel M.; Gonzalez, Emilia; Walker, Ryan G.; Thompson, Thomas B.; Wagers, Amy J.; Fong, Yick W.; Lee, Richard T.

    2016-01-01

    Rationale Growth differentiation factor 11 (GDF11) and GDF8 are members of the transforming growth factor-β superfamily sharing 89% protein sequence homology. We have previously shown that circulating GDF11 levels decrease with age in mice. However, a recent study by Egerman et al reported that GDF11/8 levels increase with age in mouse serum. Objective Here, we clarify the direction of change of circulating GDF11/8 levels with age and investigate the effects of GDF11 administration on the murine heart. Methods and Results We validated our previous finding that circulating levels of GDF11/8 decline with age in mice, rats, horses, and sheep. Furthermore, we showed by Western analysis that the apparent age-dependent increase in GDF11 levels, as reported by Egerman et al, is attributable to cross-reactivity of the anti-GDF11 antibody with immunoglobulin, which is known to increase with age. GDF11 administration in mice rapidly activated SMAD2 and SMAD3 signaling in myocardium in vivo and decreased cardiac mass in both young (2-month-old) and old (22-month-old) mice in a dose-dependent manner after only 9 days. Conclusions Our study confirms an age-dependent decline in serum GDF11/8 levels in multiple mammalian species and that exogenous GDF11 rapidly activates SMAD signaling and reduces cardiomyocyte size. Unraveling the molecular basis for the age-dependent decline in GDF11/8 could yield insight into age-dependent cardiac pathologies. PMID:26489925

  13. Associations between iron oxyhydroxide nanoparticle growth and metal adsorption/structural incorporation

    SciTech Connect

    Kim, C.S.; Lentini, C.J.; Waychunas, G.A.

    2008-09-15

    The interaction of metal ions and oxyanions with nanoscale mineral phases has not yet been extensively studied despite the increased recognition of their prevalence in natural systems as a significant component of geomedia. A combination of macroscopic uptake studies to investigate the adsorption behavior of As(V), Cu(II), Hg(II), and Zn(II) onto nanoparticulate goethite ({alpha}-FeOOH) as a function of aging time at elevated temperature (75 C) and synchrotron-based X-ray studies to track changes in both the sorption mode and the rate of nanoparticle growth reveal the effects that uptake has on particle growth. Metal(loid) species which sorb quickly to the iron oxyhydroxide particles (As(V), Cu(II)) appear to passivate the particle surface, impeding the growth of the nanoparticles with progressive aging; in contrast, species that sorb more slowly (Hg(II), Zn(II)) have considerably less impact on particle growth. Progressive changes in the speciation of these particular metals with time suggest shifts in the mode of metal uptake with time, possibly indicating structural incorporation of the metal(loid) into the nanoparticle; this is supported by the continued increase in uptake concomitant with particle growth, implying that metal species may transform from surface-sorbed species to more structurally incorporated forms. This type of incorporation would have implications for the long-term fate and mobility of metals in contaminated regions, and affect the strategy for potential remediation/modeling efforts.

  14. Modeling age-specific cancer incidences using logistic growth equations: implications for data collection.

    PubMed

    Shen, Xing-Rong; Feng, Rui; Chai, Jing; Cheng, Jing; Wang, De-Bin

    2014-01-01

    Large scale secular registry or surveillance systems have been accumulating vast data that allow mathematical modeling of cancer incidence and mortality rates. Most contemporary models in this regard use time series and APC (age-period-cohort) methods and focus primarily on predicting or analyzing cancer epidemiology with little attention being paid to implications for designing cancer registry, surveillance or evaluation initiatives. This research models age-specific cancer incidence rates using logistic growth equations and explores their performance under different scenarios of data completeness in the hope of deriving clues for reshaping relevant data collection. The study used China Cancer Registry Report 2012 as the data source. It employed 3-parameter logistic growth equations and modeled the age-specific incidence rates of all and the top 10 cancers presented in the registry report. The study performed 3 types of modeling, namely full age-span by fitting, multiple 5-year- segment fitting and single-segment fitting. Measurement of model performance adopted adjusted goodness of fit that combines sum of squred residuals and relative errors. Both model simulation and performance evalation utilized self-developed algorithms programed using C# languade and MS Visual Studio 2008. For models built upon full age-span data, predicted age-specific cancer incidence rates fitted very well with observed values for most (except cervical and breast) cancers with estimated goodness of fit (Rs) being over 0.96. When a given cancer is concerned, the R valuae of the logistic growth model derived using observed data from urban residents was greater than or at least equal to that of the same model built on data from rural people. For models based on multiple-5-year-segment data, the Rs remained fairly high (over 0.89) until 3-fourths of the data segments were excluded. For models using a fixed length single-segment of observed data, the older the age covered by the corresponding

  15. 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

  16. Kinetic-structural analysis of neuronal growth cone veil motility.

    PubMed

    Mongiu, Anne K; Weitzke, Elizabeth L; Chaga, Oleg Y; Borisy, Gary G

    2007-03-15

    Neuronal growth cone advance was investigated by correlative light and electron microscopy carried out on chick dorsal root ganglion cells. Advance was analyzed in terms of the two principal organelles responsible for protrusive motility in the growth cone - namely, veils and filopodia. Veils alternated between rapid phases of protrusion and retraction. Electron microscopy revealed characteristic structural differences between the phases. Our results provide a significant advance in three respects: first, protruding veils are comprised of a densely branched network of actin filaments that is lamellipodial in appearance and includes the Arp2/3 complex. On the basis of this structural and biomarker evidence, we infer that the dendritic nucleation and/or array-treadmilling mechanism of protrusive motility is conserved in veil protrusion of growth cones as in the motility of fibroblasts; second, retracting veils lack dendritic organization but contain a sparse network of long filaments; and third, growth cone filopodia have the capacity to nucleate dendritic networks along their length, a property consistent with veil formation seen at the light microscopic level but not previously understood in supramolecular terms. These elements of veil and filopodial organization, when taken together, provide a conceptual framework for understanding the structural basis of growth cone advance. PMID:17327278

  17. Relationship between cognitive function, growth hormone and insulin-like growth factor I plasma levels in aged subjects.

    PubMed

    Rollero, A; Murialdo, G; Fonzi, S; Garrone, S; Gianelli, M V; Gazzerro, E; Barreca, A; Polleri, A

    1998-01-01

    Basal growth hormone (GH) and insulin-like growth factor I (IGF-I) as well as GH responses to GH-releasing hormone (GHRH) were studied in 22 subjects (7 females, 15 males), aged between 65 and 86 years. The study was aimed at investigating the possible correlations between the age-dependent GH-IGF-I axis decline and the cognitive function - assessed by the Mini Mental State Examination (MMSE). The relationship between hormonal data, cognition and age, body weight, body mass index (BMI), some nutritional indices (triceps skinfolds, TSF, mid-arm circumference, MAC), and physical activity - quantified by the physical functioning index (PFI)--were also analyzed. GH basal levels were within the normal range, while GH responses to GHRH were blunted in most cases. GH peaks after GHRH were directly correlated with GH basal values. IGF-I serum levels were found to be in the lower part of the reference range for adult subjects or below it. GH responses to GHRH, but not GH and IGF-I basal levels, were inversely correlated with subject age. GH secretion areas after GHRH were inversely correlated with BMI, but no further correlations between GH data and clinical or nutritional parameters were found. MMSE values directly correlated with MAC and PFI values. IGF-I levels were directly correlated with MMSE scores, being lowered in patients with more advanced cognitive deterioration, and with MAC values--the decrease of which is thought to reflect protein caloric malnutrition--but not with body weight, BMI, TSF and PFI. MMSE-related protein caloric malnutrition and decreased physical activity possibly take part in affecting IGF- I function in subjects with mild cognitive impairment and, reciprocally, IGF-I decrement might affect neuronal function. PMID:9732206

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

    SciTech Connect

    Poussart,P.; Myneni, S.; Lanzirotti, A.

    2006-01-01

    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. However, dendrochronological techniques have found limited applications in the tropics because trees often lack visible growth rings. Alternative methods exist (dendrometry, radio- and stable isotopes), 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 {le}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.

  19. 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.

  20. 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.

  1. Aging effects on the structure underlying balance abilities tests.

    PubMed

    Urushihata, Toshiya; Kinugasa, Takashi; Soma, Yuki; Miyoshi, Hirokazu

    2010-01-01

    Balance impairment is one of the biggest risk factors for falls reducing inactivity, resulting in nursing care. Therefore, balance ability is crucial to maintain the activities of independent daily living of older adults. Many tests to assess balance ability have been developed. However, few reports reveal the structure underlying results of balance performance tests comparing young and older adults. Covariance structure analysis is a tool that is used to test statistically whether factorial structure fits data. This study examined aging effects on the factorial structure underlying balance performance tests. Participants comprised 60 healthy young women aged 22 ± 3 years (young group) and 60 community-dwelling older women aged 69 ± 5 years (older group). Six balance tests: postural sway, one-leg standing, functional reach, timed up and go (TUG), gait, and the EquiTest were employed. Exploratory factor analysis revealed that three clearly interpretable factors were extracted in the young group. The first factor had high loadings on the EquiTest, and was interpreted as 'Reactive'. The second factor had high loadings on the postural sway test, and was interpreted as 'Static'. The third factor had high loadings on TUG and gait test, and was interpreted as 'Dynamic'. Similarly, three interpretable factors were extracted in the older group. The first factor had high loadings on the postural sway test and the EquiTest and therefore was interpreted as 'Static and Reactive'. The second factor, which had high loadings on the EquiTest, was interpreted as 'Reactive'. The third factor, which had high loadings on TUG and the gait test, was interpreted as 'Dynamic'. A covariance structure model was applied to the test data: the second-order factor was balance ability, and the first-order factors were static, dynamic and reactive factors which were assumed to be measured based on the six balance tests. Goodness-of-fit index (GFI) of the models were acceptable (young group, GFI

  2. Aging Effects on the Structure Underlying Balance Abilities Tests

    PubMed Central

    Kinugasa, Takashi; Soma, Yuki; Miyoshi, Hirokazu

    2010-01-01

    Balance impairment is one of the biggest risk factors for falls reducing inactivity, resulting in nursing care. Therefore, balance ability is crucial to maintain the activities of independent daily living of older adults. Many tests to assess balance ability have been developed. However, few reports reveal the structure underlying results of balance performance tests comparing young and older adults. Covariance structure analysis is a tool that is used to test statistically whether factorial structure fits data. This study examined aging effects on the factorial structure underlying balance performance tests. Participants comprised 60 healthy young women aged 22 ± 3 years (young group) and 60 community-dwelling older women aged 69 ± 5 years (older group). Six balance tests: postural sway, one-leg standing, functional reach, timed up and go (TUG), gait, and the EquiTest were employed. Exploratory factor analysis revealed that three clearly interpretable factors were extracted in the young group. The first factor had high loadings on the EquiTest, and was interpreted as ‘Reactive’. The second factor had high loadings on the postural sway test, and was interpreted as ‘Static’. The third factor had high loadings on TUG and gait test, and was interpreted as ‘Dynamic’. Similarly, three interpretable factors were extracted in the older group. The first factor had high loadings on the postural sway test and the EquiTest and therefore was interpreted as ‘Static and Reactive’. The second factor, which had high loadings on the EquiTest, was interpreted as ‘Reactive’. The third factor, which had high loadings on TUG and the gait test, was interpreted as ‘Dynamic’. A covariance structure model was applied to the test data: the second-order factor was balance ability, and the first-order factors were static, dynamic and reactive factors which were assumed to be measured based on the six balance tests. Goodness-of-fit index (GFI) of the models were

  3. Whisker Growth Behavior of Sn58Bi Solder Coatings Under Isothermal Aging

    NASA Astrophysics Data System (ADS)

    Ma, Limin; Zuo, Yong; Liu, Sihan; Guo, Fu

    2016-01-01

    Whisker formation is a frequently occurring problem in the electronica industry, causing damage to fine-pitch electrical components. Several theories and models have been developed to describe the whisker growth, and many attempts have been made to find solutions for this issue. Most of the previous literature addressed the formation of Sn whiskers, while some attention was focused on Bi-rich whiskers. Moreover, investigation of different types of whiskers would be beneficial for understanding of the fundamental processes behind of the whisker growth. In our work, we analyze and discuss the growth of Bi-rich whiskers in eutectic Sn58Bi solder coatings under isothermal aging conditions. A possible growth mechanism for Bi-whiskers in the coating is proposed. Two processes contributed to the whisker growth. One process was the chemical reaction between Cu and Sn atoms to form Cu6Sn5. Cu atoms were inexhaustibly introduced into the coating from the substrate and caused the formation of Cu6Sn5. This process provided the driving force and was a sufficient condition for the growth of Bi-rich whiskers. The second process was the segregation of Bi atoms driven by the gradient of the Bi atoms' concentration. This process was the necessary condition for Bi-whiskers growth.

  4. Effects of ration and temperature on growth of age-0 Atlantic sturgeon

    USGS Publications Warehouse

    Kelly, J.L.; Arnold, D.E.

    1999-01-01

    Our objective was to gain insight into the optimum temperature and ration for growth of age-0 Atlantic sturgeon Acipenser oxyrinchus in culture. We conducted two trials, each for 8 weeks. Trial 1 started with 60-g fish, trial 2 started with 0 3-g fish. Water temperatures of 15, 17, and 19??C were used separately in each trial. Rations (dry food, wet weight of fish) for 60-g fish were 0.5, 1.0, and 1.5% of biomass per day, for 0.3-g fish, rations were 3, 5, and 7% of biomass per day. We set up three tank replicates, of equal fish biomass, at each combination of temperature and ration. The highest growth rate in trial 1 (for 60-g fish) was 0.014/d at 15??C and the 1.5% ration, although this growth rate was not significantly different from the growth rate at 17??C and 1.5% ration or at 17??C and 1.0% ration. The highest growth rate in trial 2 (for 0.3-g fish) was 0.067/d at 19??C and the 7.0% ration. Instantaneous growth at these conditions was significantly different from all other combinations of temperature and ration. Although these results may not completely define the temperature and ration under which fish could achieve maximum growth rate, they provide a solid starting point for further development of Atlantic sturgeon culture.

  5. Latent Growth Curves within Developmental Structural Equation Models.

    ERIC Educational Resources Information Center

    McArdle, J. J.; Epstein, David

    1987-01-01

    Uses structural equation modeling to combine traditional ideas from repeated-measures ANOVA with some traditional ideas from longitudinal factor analysis. The model describes a latent growth curve model that permits the estimation of parameters representing individual and group dynamics. (Author/RH)

  6. 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)…

  7. Growth increment periodicity in the shell of the razor clam Ensis directus using stable isotopes as a method to validate age

    NASA Astrophysics Data System (ADS)

    Cardoso, J. F. M. F.; Nieuwland, G.; Witbaard, R.; van der Veer, H. W.; Machado, J. P.

    2013-07-01

    To evaluate the role of the razor clam Ensis directus in Dutch coastal waters, understanding its population dynamics is important. As such, the age structure of the population forms a key parameter. Accurate age determination in bivalve shells is not always straightforward due to the difficulty of interpreting externally visible growth lines. In the present paper, we aimed at validating the seasonality in growth line formation using visual techniques in combination with stable oxygen and carbon isotope analyses (δ18O and δ13C). High δ18O values in the shell coincided with growth marks on the external surface of the valve and in acetate peels of the shell's cross section. Most shell δ18O samples were assigned to the months from June to September. From November to March no samples were retrieved, indicating that the shell did not grow. The lowest reconstructed temperature (6.3 °C) suggests that ~ 6 °C may be the threshold temperature for growth. Nevertheless, most of the reconstructed values fell above 14.5 °C, indicating that growth occurred mainly in the summer at relatively high temperatures. Shell δ13C profiles followed a more or less seasonal cycle, but no direct relationship could be made between δ13C values and annual growth lines. Although counting external annual growth lines led to a correct estimation of age and consequently of growth rates, we recommend analysing acetate peels of cross sections to support the distinction between annual lines and disturbance lines.

  8. Age and growth of the whitefish Coregonus clupeaformis, of Munising Bay, Lake Superior

    USGS Publications Warehouse

    Edsall, Thomas A.

    1960-01-01

    This study is based on a sample of 415 whitefish collected in 1953 from an unexploited population in Munising Bay, Lake Superior. Gill-net and trawl catches had different length-frequency distributions and age compositions, but estimates of growth from the two catches were very similar. The body-scale relation is a straight line with an intercept of 1.5 inches. Weight of Munising Bay whitefish captured in June increased as the 3.17 power of the length. Growth in length and weight of Munising Bay whitefish was the slowest yet reported from Great Lakes waters. Munising Bay whitefish required nearly 8 years to reach a length of 10 inches and a full 13 years to reach 15 inches. Slightly more than 8 years were required to reach a weight of 8 ounces and a little less than 14 years to reach 1 pound. The sex ratio of the Munising Bay whitefish exhibited no systematic change with an increase in age. The entire sample for which ages were determined contained 52 percent males. Munising Bay whitefish matured at much shorter lengths but at a greater age than reported for other Great Lakes whitefish populations. The smallest mature males were in the 11.5- to 11.9-inch length interval (age-group VII) and all males longer than 14.4 inches (age-group XII) were mature. The first mature females appeared at 12.0-12.4 inches (age-group X) and all females longer than 14.9 inches (age-group XII) were mature. The more rapidly growing individuals matured earlier than the slow-growing ones.

  9. 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.

  10. Age, growth and maturity of the pelagic thresher Alopias pelagicus and the scalloped hammerhead Sphyrna lewini.

    PubMed

    Drew, M; White, W T; Dharmadi; Harry, A V; Huveneers, C

    2015-01-01

    Indonesia has the greatest reported chondrichthyan catches worldwide, with c.110,000 t caught annually. The pelagic thresher (Alopias pelagicus) and scalloped hammerhead (Sphryna lewini) together comprise about 25% of the total catches of sharks landed in Indonesia. Age and growth parameters were estimated for A. pelagicus and S. lewini from growth-band counts of thin-cut vertebral sections. Alopias pelagicus (n = 158) and S. lewini (n = 157) vertebrae were collected from three Indonesian fish markets over a 5 year period. A multi-model analysis was used to estimate growth parameters for both species. The models of best fit for males and females for A. pelagicus was the three-parameter logistic (L∞ = 3169 mm LT , k = 0·2) and the two-parameter von Bertalanffy models (L∞ = 3281 mm LT , k = 0·12). Age at maturity was calculated to be 10·4 and 13·2 years for males and females, respectively, and these are the oldest estimated for this species. The samples of S. lewini were heavily biased towards females, and the model of best fit for males and females was the three-parameter Gompertz (L∞ = 2598 mm LT , k = 0·15) and the two-parameter Gompertz (L∞ = 2896 mm LT , k= 0·16). Age at maturity was calculated to be 8·9 and 13·2 years for males and females, respectively. Although numerous age and growth studies have previously been undertaken on S. lewini, few studies have been able to obtain adequate samples from all components of the population because adult females, adult males and juveniles often reside in different areas. For the first time, sex bias in this study was towards sexually mature females, which are commonly lacking in previous biological studies on S. lewini. Additionally, some of the oldest aged specimens and highest age at maturity for both species were observed in this study. Both species exhibit slow rates of growth and late age at maturity, highlighting the need for a re-assessment of the relative resilience of these two

  11. 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

  12. Age and growth of albacore Thunnus alalunga in the North Pacific Ocean.

    PubMed

    Chen, K-S; Shimose, T; Tanabe, T; Chen, C-Y; Hsu, C-C

    2012-05-01

    The age and growth of North Pacific albacore Thunnus alalunga were investigated using obliquely sectioned sagittal otoliths from samples of 126 females and 148 males. Otolith edge analysis indicated that the identified annulus in a sagittal otolith is primarily formed during the period from September to February. The assessments of the fish age at first annulus formation indicated that the first annulus represents an age of <1 year. This study presents an age estimate (0·75 years) for the formation of the first annulus. The oldest fish ages observed in this study were 10 years for females and 14 years for males. The von Bertalanffy growth parameters of females estimated were L(∞) = 103·5 cm in fork length (L(F) ), K = 0·340 year(-1) and t(0) = -0·53 years, and the parameters of males were L(∞) = 114·0 cm, K = 0·253 year(-1) and t(0) = -1·01 years. Sexual size dimorphism between males and females seemed to occur after reaching sexual maturity. The coefficients of the power function for expressing the L(F) -mass relationship obtained from sex-pooled data were a = 2·964 × 10(-5) and b = 2·928. PMID:22551185

  13. Effect of host age on the transplantation, growth, and radiation response of EMT6 tumors

    SciTech Connect

    Rockwell, S.

    1981-02-01

    The characteristics of EMT6 tumors in young adult and aged BALB/c KaRw mice were compared. The number of tumor cells implanted s.c. necessary to cause tumors in 50% of the injection sites was lower in aging than in young adult mice. The latent period of intradermally implanted tumors was shorter in aging mice than in young animals; however, the growth curves of established tumors were similar. The number and appearance of lung colonies after injection of cells i.v. and the pattern of spontaneous metastases were similar in young and aged animals. Radiation dose-response curves for the cells of tumors in young and aging mice were different and suggested that the proportion of hypoxic cells was higher in tumors on aging animals. These findings suggest that both immunological and nonimmunological tumor-host interactions differ in young and aged animals and that such factors may influence the natural history of the tumor and the response of the tumor to treatment.

  14. 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. PMID:27318130

  15. Impact of structural aging on seismic risk assessment of reinforced concrete structures in nuclear power plants

    SciTech Connect

    Ellingwood, B.; Song, J.

    1996-03-01

    The Structural Aging Program is addressing the potential for degradation of concrete structural components and systems in nuclear power plants over time due to aging and aggressive environmental stressors. Structures are passive under normal operating conditions but play a key role in mitigating design-basis events, particularly those arising from external challenges such as earthquakes, extreme winds, fires and floods. Structures are plant-specific and unique, often are difficult to inspect, and are virtually impossible to replace. The importance of structural failures in accident mitigation is amplified because such failures may lead to common-cause failures of other components. Structural condition assessment and service life prediction must focus on a few critical components and systems within the plant. Components and systems that are dominant contributors to risk and that require particular attention can be identified through the mathematical formalism of a probabilistic risk assessment, or PRA. To illustrate, the role of structural degradation due to aging on plant risk is examined through the framework of a Level 1 seismic PRA of a nuclear power plant. Plausible mechanisms of structural degradation are found to increase the core damage probability by approximately a factor of two.

  16. Effects of age, replicative lifespan and growth rate of human nucleus pulposus cells on selecting age range for cell-based biological therapies for degenerative disc diseases.

    PubMed

    Lee, J S; Lee, S M; Jeong, S W; Sung, Y G; Lee, J H; Kim, K W

    2016-07-01

    Autologous disc cell implantation, growth factors and gene therapy appear to be promising therapies for disc regeneration. Unfortunately, the replicative lifespan and growth kinetics of human nucleus pulposus (NP) cells related to host age are unclear. We investigated the potential relations among age, replicative lifespan and growth rate of NP cells, and determined the age range that is suitable for cell-based biological therapies for degenerative disc diseases. We used NP tissues classified by decade into five age groups: 30s, 40s, 50s, 60s and 70s. The mean cumulative population doubling level (PDL) and population doubling rate (PDR) of NP cells were assessed by decade. We also investigated correlations between cumulative PDL and age, and between PDR and age. The mean cumulative PDL and PDR decreased significantly in patients in their 60s. The mean cumulative PDL and PDR in the younger groups (30s, 40s and 50s) were significantly higher than those in the older groups (60s and 70s). There also were significant negative correlations between cumulative PDL and age, and between PDR and age. We found that the replicative lifespan and growth rate of human NP cells decreased with age. The replicative potential of NP cells decreased significantly in patients 60 years old and older. Young individuals less than 60 years old may be suitable candidates for NP cell-based biological therapies for treating degenerative disc diseases. PMID:27149303

  17. Aging Optimization of Aluminum-Lithium Alloy C458 for Application to Cryotank Structures

    NASA Technical Reports Server (NTRS)

    Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Rioja, R.

    2003-01-01

    Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 (Al-1.0 Li-4.0 Cu-0.4 Mg-0.4 Ag-0.12 Zr) for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. These newer alloys generally have lithium content less than 2 wt. % and their composition and processing have been carefully tailored to increase the toughness and reduce the mechanical property anisotropy of the earlier generation alloys such 2090 and 8090. Alloy processing, particularly the aging treatment, has a significant influence on the strength-toughness combinations and their dependence on service environments for aluminum-lithium alloys. Work at NASA Marshall Space Flight Center on alloy 2195 has shown that the cryogenic toughness can be improved by employing a two-step aging process. This is accomplished by aging at a lower temperature in the first step to suppress nucleation of the strengthening precipitate at sub-grain boundaries while promoting nucleation in the interior of the grains. Second step aging at the normal aging temperature results in precipitate growth to the optimum size. A design of experiments aging study was conducted for plate. To achieve the T8 temper, Alloy C458 (Al-1.8 Li-2.7 Cu-0.3 Mg- 0.08 Zr-0.3 Mn-0.6 Zn) is typically aged at 300 F for 24 hours. In this study, a two-step aging treatment was developed through a comprehensive 24 full factorial design of experiments study and the typical one-step aging used as a reference. Based on the higher lithium content of C458 compared with 2195, the first step aging temperature was varied between 175 F and 250 F. The second step aging temperatures was

  18. Age and growth of the rock bass, Ambloplites rupestris (Rafinesque), in Nebish Lake, Wisconsin

    USGS Publications Warehouse

    Hile, Ralph

    1941-01-01

    studies of the age and growth of the rock bass (Wright, 1929), whitefish (Hile and Deason, 1934), yellow perch (Schneberger, 1935), cisco (Hile, 1936a), muskellunge (Schloemer, 1936, 1938), largemouth black bass (Bennett, 1937), common sucker (Spoor, 1938), and smalimouth black bass (Bennett, 1938). A total of five mimeographed reports on the growth of game fish in Wisconsin has been issued by Juday and Schneberger (1930, 1933), Juday and Bennett (1935), and Juday and Schloemer (1936,. 1938). In addition there have appeared two publications on the morphometry of the cisco (Hile 193Gb, 1937), three dealing with the parasites of fishes in the region (Cross 1934, 1935, 1938) and one on the food of fishes (Couey, 1935). A paper by Hile and Juday on the bathymetric distribution of fish will appear simultaneously with the present study of the rock bass. A contribution on the growth of the bluegill by Schloemer will be published in the near future.

  19. Age, growth and mortality in four populations of the boring bivalve Lithophaga patagonica from Argentina

    NASA Astrophysics Data System (ADS)

    Bagur, María; Richardson, Christopher A.; Gutiérrez, Jorge L.; Arribas, Lorena P.; Doldan, M. Socorro; Palomo, M. Gabriela

    2013-08-01

    The boring bivalve Lithophaga patagonica (d'Orbigny, 1842) is a locally abundant inhabitant of hard substrata in the coastal waters of the Southwestern Atlantic. In this paper, we describe the growth, age and mortality of three intertidal rock-boring populations of L. patagonica and one subtidal oyster shell (Ostrea puelchana) boring population. An analysis of acetate peel replicas of shell sections showed that L. patagonica slows down its growth during autumn-winter, which leads to changes in the direction and rate of shell deposition and the formation of conspicuous annual (low temperature induced) clefts in the shell margin. Cleft counts and Von Bertalanffy growth analyses indicated that maximum age varies from 4 years in the oyster-boring population to 13 years in a rock-boring one (longevity estimates varied between 6.5 and 15 years, respectively). Maximum asymptotic length (L∞) and Von Bertalanffy growth constant (K) were also variable between populations (L∞ between 14.76 and 36.95 mm and K from 0.20 to 0.90 yr- 1 respectively). Mortality rates were higher at the two southernmost populations. Type (rock vs. oyster), composition and hardness of the substrata are likely the main factors controlling the observed differences between populations.

  20. Growth of age-0 steelhead (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) in the Pine River watershed, Alcona County, Michigan

    SciTech Connect

    Bellgraph, Brian J.; Thompson, Bradley E.; Hayes, Daniel B.; Riley, Timothy S.

    2006-12-01

    We sampled ten sites within the Pine River watershed, Alcona County, Michigan. In 2001, age-0 steelhead (Oncorhynchus mykiss) were collected to determine growth rates. In 2002, emergence dates of steelhead were determined by observational studies and age-0 steelhead and brook trout (Salvelinus fontinalis) were collected to determine growth rates. Steelhead emergence occurred from late June to mid-July 2002. Growth rates of both species varied among branches within the watershed (P<0.05). Steelhead growth varied from 0.24 to 0.42 mm/day and brook trout growth varied from 0.22 to 0.37 mm/day.

  1. Growth of Geographic Atrophy in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT)

    PubMed Central

    Grunwald, Juan E; Pistilli, Maxwell; Ying, Gui-shuang; Maguire, Maureen G; Daniel, Ebenezer; Martin, Daniel F

    2014-01-01

    Purpose To evaluate the growth of geographic atrophy (GA) during anti-VEGF therapy. Design Cohort within clinical trial. Participants Patients included in the Comparison of Age-related Macular Degeneration (AMD) Treatments Trials (CATT) Methods Participants were randomly assigned to injections of ranibizumab or bevacizumab and to a 2-year dosing regimen of monthly or pro re nata (PRN), or to monthly for 1 year and PRN the following year. Digital color photographs and fluorescein angiograms at baseline, 1 and 2 years were evaluated for GA and the total area of GA was measured by two graders masked to treatment; differences were adjudicated. Multivariate linear mixed models of the annual change in the square root of the area included baseline demographic, treatment, and ocular characteristics on imaging as candidate risk factors. Main outcome measures GA growth rate. Results Among 1185 participants, 86 (7.3%) had GA at baseline, 120 (10.1%) developed GA during year 1 and 36 (3.0%) during year 2. Among 194 eyes evaluable for growth, the rate was 0.43 (standard error [SE]: ±0.03) mm/year. In multivariate analysis, the growth rate was 0.37 mm/year in eyes receiving bevacizumab and 0.49 mm/year in eyes receiving ranibizumab (difference 0.11, 95% Confidence Interval [CI]: (0.01, 0.22); p=0.03). Growth rate did not differ between eyes treated monthly and PRN (p=0.85). Eyes with subfoveal CNV lesions had a lower growth rate than eyes with non-subfoveal CNV lesions (difference 0.12, CI: 0.01, 0.22; p=0.03). Eyes with GA farther from the fovea had higher growth rates by 0.14 (CI: 0.01, 27) mm/year for every mm farther from the fovea. The growth rate was 0.58 mm/year for eyes with predominantly classic lesions, 0.41 mm/year for eyes with minimally classic lesions, and 0.30 mm/year for eyes with occult only lesions (p<0.01). The growth rate in eyes having a fellow eye with GA was higher by 0.13 (CI: 0.01, 0.24; p=0.03) mm/year than in eyes without GA in the fellow eye. Eyes

  2. 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.

  3. Generating folded protein structures with a lattice chain growth algorithm

    NASA Astrophysics Data System (ADS)

    Gan, Hin Hark; Tropsha, Alexander; Schlick, Tamar

    2000-10-01

    We present a new application of the chain growth algorithm to lattice generation of protein structure and thermodynamics. Given the difficulty of ab initio protein structure prediction, this approach provides an alternative to current folding algorithms. The chain growth algorithm, unlike Metropolis folding algorithms, generates independent protein structures to achieve rapid and efficient exploration of configurational space. It is a modified version of the Rosenbluth algorithm where the chain growth transition probability is a normalized Boltzmann factor; it was previously applied only to simple polymers and protein models with two residue types. The independent protein configurations, generated segment-by-segment on a refined cubic lattice, are based on a single interaction site for each amino acid and a statistical interaction energy derived by Miyazawa and Jernigan. We examine for several proteins the algorithm's ability to produce nativelike folds and its effectiveness for calculating protein thermodynamics. Thermal transition profiles associated with the internal energy, entropy, and radius of gyration show characteristic folding/unfolding transitions and provide evidence for unfolding via partially unfolded (molten-globule) states. From the configurational ensembles, the protein structures with the lowest distance root-mean-square deviations (dRMSD) vary between 2.2 to 3.8 Å, a range comparable to results of an exhaustive enumeration search. Though the ensemble-averaged dRMSD values are about 1.5 to 2 Å larger, the lowest dRMSD structures have similar overall folds to the native proteins. These results demonstrate that the chain growth algorithm is a viable alternative to protein simulations using the whole chain.

  4. Age, growth and natural mortality of coney (Cephalopholis fulva) from the southeastern United States

    PubMed Central

    Potts, Jennifer C.; Carr, Daniel R.

    2015-01-01

    Coney (Cephalopholis fulva) sampled from recreational and commercial vessels along the southeastern coast of the United States in 1998–2013 (n = 353) were aged by counting opaque bands on sectioned sagittal otoliths. Analysis of otolith edge type (opaque or translucent) revealed that annuli formed in January–June with a peak in April. Coney were aged up to 19 years, and the largest fish measured 430 mm in total length (TL). The weight-length relationship was ln(W) = 3.03 × ln(TL) − 18.05 (n = 487; coefficient of determination [r2] = 0.91), where W = whole weight in kilograms and and TL = total length in millimeters. Mean observed sizes at ages 1, 3, 5, 10, and 19 years were 225, 273, 307, 338, and 400 mm TL, respectively. The von Bertalanffy growth equation for coney was Lt = 377 (1 − e(−0.20(t+3.53))). Natural mortality (M) estimated by Hewitt and Hoenig’s longevity-based method which integrates all ages was 0.22. Age-specific M values, estimated with the method of Charnov and others, were 0.40, 0.30, 0.26, 0.22, and 0.20 for ages 1, 3, 5, 10, and 19, respectively. PMID:25802801

  5. Age, growth and natural mortality of coney (Cephalopholis fulva) from the southeastern United States.

    PubMed

    Burton, Michael L; Potts, Jennifer C; Carr, Daniel R

    2015-01-01

    Coney (Cephalopholis fulva) sampled from recreational and commercial vessels along the southeastern coast of the United States in 1998-2013 (n = 353) were aged by counting opaque bands on sectioned sagittal otoliths. Analysis of otolith edge type (opaque or translucent) revealed that annuli formed in January-June with a peak in April. Coney were aged up to 19 years, and the largest fish measured 430 mm in total length (TL). The weight-length relationship was ln(W) = 3.03 × ln(TL) - 18.05 (n = 487; coefficient of determination [r (2)] = 0.91), where W = whole weight in kilograms and and TL = total length in millimeters. Mean observed sizes at ages 1, 3, 5, 10, and 19 years were 225, 273, 307, 338, and 400 mm TL, respectively. The von Bertalanffy growth equation for coney was Lt = 377 (1 - e ((-0.20(t+3.53)))). Natural mortality (M) estimated by Hewitt and Hoenig's longevity-based method which integrates all ages was 0.22. Age-specific M values, estimated with the method of Charnov and others, were 0.40, 0.30, 0.26, 0.22, and 0.20 for ages 1, 3, 5, 10, and 19, respectively. PMID:25802801

  6. 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. )

  7. 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

  8. 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

  9. Influence of homology and node age on the growth of protein-protein interaction networks

    NASA Astrophysics Data System (ADS)

    Bottinelli, Arianna; Bassetti, Bruno; Lagomarsino, Marco Cosentino; Gherardi, Marco

    2012-10-01

    Proteins participating in a protein-protein interaction network can be grouped into homology classes following their common ancestry. Proteins added to the network correspond to genes added to the classes, so the dynamics of the two objects are intrinsically linked. Here we first introduce a statistical model describing the joint growth of the network and the partitioning of nodes into classes, which is studied through a combined mean-field and simulation approach. We then employ this unified framework to address the specific issue of the age dependence of protein interactions through the definition of three different node wiring or divergence schemes. A comparison with empirical data indicates that an age-dependent divergence move is necessary in order to reproduce the basic topological observables together with the age correlation between interacting nodes visible in empirical data. We also discuss the possibility of nontrivial joint partition and topology observables.

  10. 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. PMID:15535461

  11. Structural and cellular changes during bone growth in healthy children.

    PubMed

    Parfitt, A M; Travers, R; Rauch, F; Glorieux, F H

    2000-10-01

    Normal postnatal bone growth is essential for the health of adults as well as children but has never been studied histologically in human subjects. Accordingly, we analyzed iliac bone histomorphometric data from 58 healthy white subjects, aged 1.5-23 years, 33 females and 25 males, of whom 48 had undergone double tetracycline labeling. The results were compared with similar data from 109 healthy white women, aged 20-76 years, including both young adult reference ranges and regressions on age. There was a significant increase with age in core width, with corresponding increases in both cortical width and cancellous width. In cancellous bone there were increases in bone volume and trabecular thickness, but not trabecular number, wall thickness, interstitial thickness, and inferred erosion depth. Mineral apposition rates declined on the periosteal envelope and on all subdivisions of the endosteal envelope. Because of the concomitant increase in wall thickness, active osteoblast lifespan increased substantially. Bone formation rate was almost eight times higher on the outer than on the inner periosteum, and more than four times higher on the inner than on the outer endocortical surface. On the cancellous surface, bone formation rate and activation frequency declined in accordance with a fifth order polynomial that matched previously published biochemical indices of bone turnover. The analysis suggested the following conclusions: (1) Between 2 and 20 years the ilium grows in width by periosteal apposition (3.8 mm) and endocortical resorption (3.2 mm) on the outer cortex, and net periosteal resorption (0.4 mm) and net endocortical formation (1.0 mm) on the inner cortex. (2) Cortical width increases from 0.52 mm at age 2 years to 1.14 mm by age 20 years. To attain adult values there must be further endocortical apposition of 0.25 mm by age 30 years, at a time when cancellous bone mass is declining. (3) Lateral modeling drift of the outer cortex enlarges the marrow cavity

  12. Tectonic structures on Mercury: kinematics and age dating

    NASA Astrophysics Data System (ADS)

    Giacomini, Lorenza; Massironi, Matteo; Rothery, David; Di Achille, Gaetano; Marchi, Simone; Galluzzi, Valentina; Ferrari, Sabrina; Fassett, Caleb; Cremonese, Gabriele

    2015-04-01

    At a global scale, Mercury is dominated by contractional features manifested as lobate scarps, wrinkle ridges and high-relief ridges. Here, we show that some of these features are associated with strike-slip kinematic indicators, which we identified using flyby and orbital Mercury Dual Imaging System (MDIS) data and digital terrain models. We recognize oblique-shear kinematics along lobate scarps and high-relief ridges by means of (1) map geometries of fault patterns (frontal thrusts bordered by lateral ramps, strike-slip duplexes, restraining bends); (2) structural morphologies indicating lateral shearing (en echelon folding, pop-ups, pull-aparts); and (3) estimates of offsets based on displaced crater rims and differences in elevation between pop-up structures and pull-apart basins and their surroundings. Transpressional faults, documented across a wide range of latitudes, are found associated with reactivated rims of ancient buried basins and, in most cases, linked to frontal thrusts as lateral ramps hundreds of kilometres long. This latter observation suggests stable directions of tectonic transport over wide regions of Mercury's surface. In contrast, global cooling would imply an overall isotropic contraction with limited processes of lateral shearing induced by pre-existent lithospheric heterogeneities. Mantle convection therefore may have played an important role during the early tectonic evolution of Mercury. Estimating absolute model ages for compressional features and comparing it from what it is envisaged with thermal modeling based on cooling alone can be useful in determining if other processes could have been responsible for lobate scarps nucleation. In particular, ages more ancient that the one predicted by the models would imply other kind of tectonic processes ongoing during the early evolution of Mercury . For this reason, we date an extended thrust system, which we term the Blossom Thrust System, located between 80°E and 100°E, and 30°N and 15

  13. Orchestrated structure evolution: modeling growth-regulated nanomanufacturing.

    PubMed

    Abbasi, Shaghayegh; Kitayaporn, Sathana; Schwartz, Daniel T; Böhringer, Karl F

    2011-04-22

    Orchestrated structure evolution (OSE) is a scalable manufacturing method that combines the advantages of top-down (tool-directed) and bottom-up (self-propagating) approaches. The method consists of a seed patterning step that defines where material nucleates, followed by a growth step that merges seeded islands into the final patterned thin film. We develop a model to predict the completed pattern based on a computationally efficient approximate Green's function solution of the diffusion equation plus a Voronoi diagram based approach that defines the final grain boundary structure. Experimental results rely on electron beam lithography to pattern the seeds, followed by the mass transfer limited growth of copper via electrodeposition. The seed growth model is compared with experimental results to quantify nearest neighbor seed-to-seed interactions as well as how seeds interact with the pattern boundary to impact the local growth rate. Seed-to-seed and seed-to-pattern interactions are shown to result in overgrowth of seeds on edges and corners of the shape, where seeds have fewer neighbors. We explore how local changes to the seed location can be used to improve the patterning quality without increasing the manufacturing cost. OSE is shown to enable a unique set of trade-offs between the cost, time, and quality of thin film patterning. PMID:21393828

  14. Structure and growth mechanism of ZnSe nanowires

    NASA Astrophysics Data System (ADS)

    Basu, Joysurya; Divakar, R.; Nowak, Julia; Hofmann, Stephan; Colli, Alan; Franciosi, A.; Carter, C. Barry

    2008-09-01

    ZnSe nanowires were grown onto Mo transmission electron microscopy (TEM) grids by MBE by suitably varying the growth parameters. In situ and high-resolution TEM studies were carried out to understand the structure, defects, and growth mechanism of this nanowire. The nanowire morphology is very sensitive to the growth parameters involved. Twin boundaries are the most commonly occurring defects in the nanowires grown under Zn-rich condition and catalytic gold particles of irregular shape are observed along the nanowire body. In the course of in situ heating the shape of the nanowire tip is observed to change at ˜178 °C. Definite growth of the nanowire starts at ˜235 °C. The diameter of the grown nanowire is almost equal to that of the catalyst gold particle present at the tip of the nanowire. In situ experimental observation and available phase-diagram information strongly suggests that nanowire growth should be possible with a solid catalyst particle though it does not rule out the possibility of the existence of a VLS mechanism.

  15. Recombinant HSP70 and mild heat shock stimulate growth of aged mesenchymal stem cells.

    PubMed

    Andreeva, N V; Zatsepina, O G; Garbuz, D G; Evgen'ev, M B; Belyavsky, A V

    2016-07-01

    Heat shock proteins including the major stress protein HSP70 support intracellular homeostasis and prevent protein damage after a temperature increase and other stressful environmental stimuli, as well as during aging. We have shown earlier that prolonged administration of recombinant human HSP70 to mice exhibiting Alzheimer's-like neurodegeneration as well as during sepsis reduces the clinical manifestations of these pathologies. Herein, we studied the action of recombinant human HSP70 on young and aged mouse mesenchymal stem cells (MSCs) in culture. The results obtained indicate that HSP70 at concentrations of 2 μg/ml and higher significantly stimulates growth of aged but not young MSCs. A similar effect is produced by application of a mild heat shock (42 °C 5 min) to the cells. Importantly, responses of young and aged MSCs to heat shock treatment of various durations differed drastically, and aged MSCs were significantly more sensitive to higher heat stress exposures than the young cells. Western blotting and protein labeling experiments demonstrated that neither mild heat shock nor exogenous HSP70 administration resulted in significant endogenous HSP70 induction in young and aged MSCs, whereas mild heat shock increased HSC70 levels in aged MSCs. The results of this study suggest that the administration of exogenous HSP70 and the application of mild heat stress may produce a certain "rejuvenating" effect on MSCs and possibly other cell types in vivo, and these interventions may potentially be used for life extension by delaying various manifestations of aging at the molecular and cellular level. PMID:27091568

  16. Growth of the Tuolumne Batholith: Zircon Crystallization Temperature, Age and Trace Element Data

    NASA Astrophysics Data System (ADS)

    Matzel, J.; Miller, J.; Mundil, R.; Wooden, J.; Mazdab, F.; Burgess, S.; Paterson, S.; Memeti, V.

    2007-12-01

    Deciphering the intrusive record of magma systems is essential to understanding the links between surface volcanism and the long-term storage and evolution of magma reservoirs. Here we use age and geochemical data from zircon crystals to track mixing between different parts of the Tuolumne Batholith (Sierra Nevada, California). U-Pb zircon TIMS analyses from all locations examined in the batholith exhibit appreciable dispersion of single crystal or crystal fragment ages (several 105 yrs to 1x106 yrs) and, in addition, display distinctly older ages that likely represent zircon crystals entrained from older parts of the Tuolumne magmatic system. Since techniques aimed at eliminating Pb loss (and thus age scatter) have been employed prior to analysis, we interpret the age dispersion to reflect real variation in the timing of zircon crystallization. Two samples that show a high degree of age dispersion (> 1 Myr) were selected for trace element analysis and Ti- in zircon geothermometry by SHRIMP-RG. Crystallization temperatures ranged from 780-640°C and averaged 695°C (aTiO2 0.75 based on presence of titanite). No clear correlation exists between crystal age and temperature, and in most cases, the temperatures from crystal centers are within uncertainty of the temperatures at the rims. Trace element ratios vary systematically with temperature (e.g. decreasing Th/U ratio with decreasing T) and are attributed to fractionation, although neither sample represents strongly fractionated melt. Low total Zr indicates that the magmas were initially undersaturated in zircon when emplaced, which is also consistent with late zircon crystallization. Combined evidence from TIMS age analyses, geothermometry and trace element data suggests that entrainment of zircon from older parts of the magmatic system occurred late in the history of the batholith, and recycling of zircon crystals during successive magmatic injections is compatible with progressive growth of a large, long

  17. The controlled growth method - A tool for structural optimization

    NASA Technical Reports Server (NTRS)

    Hajela, P.; Sobieszczanski-Sobieski, J.

    1981-01-01

    An adaptive design variable linking scheme in a NLP based optimization algorithm is proposed and evaluated for feasibility of application. The present scheme, based on an intuitive effectiveness measure for each variable, differs from existing methodology in that a single dominant variable controls the growth of all others in a prescribed optimization cycle. The proposed method is implemented for truss assemblies and a wing box structure for stress, displacement and frequency constraints. Substantial reduction in computational time, even more so for structures under multiple load conditions, coupled with a minimal accompanying loss in accuracy, vindicates the algorithm.

  18. Fatigue and fatigue crack growth processes in hard tissues: The importance of age and surface integrity

    NASA Astrophysics Data System (ADS)

    Majd, Hessam

    With the progressive increase in partially and fully dentate seniors, fracture has become an increasingly common form of restored tooth failure. Dentin undergoes progressive changes in microstructure with patient age, and studies are now suggesting that there is a reduction in fatigue strength and fatigue crack growth resistance of this tissue. This dissertation explores aging of dentin, the influence of flaws that are introduced during restorative processes on the fatigue properties of dentin, and proposes models for characterizing the damage initiation and growth process during fatigue of dentin. Results from this investigation show that the fatigue crack growth properties (Paris Law parameters (C, m) andDeltaKth) of human dentin undergo the most significant changes at a patient age of 42 years. Based on the fatigue crack growth responses, three age groups were established including young (age≤33), aged (34≤age ≤49) and old (50≤age) patients for further analysis. There were significant differences in the initiation and growth behavior between the tissues of patients from the three age groups. With regards to the influence of restorative processes, there was no influence on the quasi-static responses of dentin. However, the endurance limit of dentin treated with the dental burs (28 MPa) and abrasive air jet (35 MPa) were approximately 36% and 20% lower than that of the control (44 MPa), respectively. Both cutting processes caused a significant reduction (p≤0.0001) in fatigue strength. An accumulative damage model was developed to characterize fatigue of the control and bur treated dentin as well as provide a model for fatigue life prediction. The damage models were derived as a function of number of loading cycles (N), and ratio of applied stress to ultimate strength (r). The developed models provide estimations for the initial state of damage, the state of damage during the life, as well as the damage accumulation rate for cyclic loading of dentin

  19. National Health Expenditure Growth in the 1980's: An Aging Population, New Technologies, and Increasing Competition

    PubMed Central

    Freeland, Mark S.; Schendler, Carol Ellen

    1983-01-01

    Health care spending in the United States more than tripled between 1971 and 1981, increasing from $83 billion to $287 billion. This growth in health sector spending substantially outpaced overall growth in the economy, averaging 13.2 percent per year compared to 10.5 percent for the gross national product (GNP). By 1981, one out of every ten dollars of GNP was spent on health care, compared to one out of every thirteen dollars of GNP in 1971. If current trends continue and if present health care financing arrangements remain basically unchanged, national health expenditures are projected to reach approximately $756 billion in 1990 and consume roughly 12 percent of GNP. The focal issue in health care today is cost and cost Increases. The outlook for the 1980's is for continued rapid growth but at a diminished rate. The primary force behind this moderating growth is projected lower inflation. However, real growth rates are also expected to moderate slightly. The chief factors influencing the growth of health expenditures in the eighties are expected to be aging of the population, new medical technologies, increasing competition, restrained public funding, growth in real income, increased health manpower, and a deceleration in economy-wide inflation. Managers, policy makers and providers in the health sector, as in all sectors, must include in today's decisions probable future trends. Inflation, economic shocks, and unanticipated outcomes of policies over the last decade have intensified the need for periodic assessments of individual industries and their relationship to the macro economy. This article provides such an assessment for the health care industry. Baseline current-law projections of national health expenditures are made to 1990. PMID:10309852

  20. Molecular design for growth of supramolecular membranes with hierarchical structure.

    PubMed

    Zha, R Helen; Velichko, Yuri S; Bitton, Ronit; Stupp, Samuel I

    2016-02-01

    Membranes with hierarchical structure exist in biological systems, and bio-inspired building blocks have been used to grow synthetic analogues in the laboratory through self-assembly. The formation of these synthetic membranes is initiated at the interface of two aqueous solutions, one containing cationic peptide amphiphiles (PA) and the other containing the anionic biopolymer hyaluronic acid (HA). The membrane growth process starts within milliseconds of interface formation and continues over much longer timescales to generate robust membranes with supramolecular PA-HA nanofibers oriented orthogonal to the interface. Computer simulation indicates that formation of these hierarchically structured membranes requires strong interactions between molecular components at early time points in order to generate a diffusion barrier between both solutions. Experimental studies using structurally designed PAs confirm simulation results by showing that only PAs with high ζ potential are able to yield hierarchically structured membranes. Furthermore, the chemical structure of such PAs must incorporate residues that form β-sheets, which facilitates self-assembly of long nanofibers. In contrast, PAs that form low aspect ratio nanostructures interact weakly with HA and yield membranes that exhibit non-fibrous fingering protrusions. Furthermore, experimental results show that increasing HA molecular weight decreases the growth rate of orthogonal nanofibers. This result is supported by simulation results suggesting that the thickness of the interfacial contact layer generated immediately after initiation of self-assembly increases with polymer molecular weight. PMID:26649980

  1. Elevated Temperature Crack Growth Behavior in HSCT Structural Materials

    NASA Technical Reports Server (NTRS)

    Saxena, Ashok

    1998-01-01

    Structures in super-sonic aircraft are subjected to conditions of high temperature and cyclic and sustained loading for extended periods of time. The durability of structures fabricated from aluminum and certain titanium alloys in such demanding conditions is of primary concern to the designers and manufacturers of futuristic transport aircraft. Accordingly, the major goal of this project was to evaluate the performance and durability of high temperature aluminum and titanium alloys for use in high speed civil transport (HSCT) structures. Additional goals were to develop time-dependent fracture mechanics methodology and test methods for characterizing and predicting elevated temperature crack growth behavior in creep-brittle materials such as ones being considered for use in HSCT structures and to explore accelerated methods of simulating microstructural degradation during service and measuring degraded properties in these materials.

  2. Three-dimensional analysis of cranial growth from 6 to 12 months of age.

    PubMed

    Meyer-Marcotty, P; Böhm, H; Linz, C; Kochel, J; Stellzig-Eisenhauer, A; Schweitzer, T

    2014-10-01

    The aim of this study was to generate three-dimensional data of the physiological growth of the infant's cranium in the significant growth phase from 6 to 12 months of age. In a longitudinal observational study non-invasive 3D data using an optical surface scanner were generated of the entire head of 52 Caucasian infants (27 females and 25 males) between the ages of 6 (T1) and 12 (T2) months. The circumference of the head increased by 6.51 per cent (from 43.50 to 46.33cm). Analysis of width and length showed that the head grows 2.84 per cent more in length, resulting in a decrease in the cranial index of 2.52 per cent (from 83.87 to 81.76 per cent). The highest increment observed was in the total volume of the cranium, with an increase of 18.76 per cent (from 1229.01 to 1459.57cm(3)). Comparison of the left and right sides of the head by measuring the diagonal symmetry difference showed a difference of only 0.37cm. Overall, the symmetry-related parameters showed an almost symmetric development of the cranium in infants. The findings should provide valuable information on physiological growth and development of the infant's cranium. Therefore the high growth rate of the cranium in the first year of life suggests that this period is a critical period in which the disruption of developmental processes may have long-lasting effects on the morphology of the cranium with a prognostically unfavourable effect of the further growth of the viscerocranium. PMID:25257925

  3. Age, growth, and gonadal characteristics of adult bighead carp, Hypophthalmichthys nobilis, in the lower Missouri River

    USGS Publications Warehouse

    Schrank, S.J.; Guy, C.S.

    2002-01-01

    Bighead carp were introduced into Arkansas in 1973 to improve water clarity in production ponds. Bighead carp subsequently escaped aquaculture facilities in the early 1980's and dispersed into the Mississippi and Missouri rivers. The first documentation of bighead carp reproduction in the Mississippi River system was in 1989. The population has increased in the Missouri River as is evident in their increased proportion in the commercial harvest since 1990. The effect of this exotic planktivore on native ecosystems of the U.S. has not been examined. Basic biological data on bighead carp Hypophthalmichthys nobilis in the Missouri River are needed to predict potential ecological problems and provide a foundation for manipulative studies. The objectives of this study were to assess age, growth, and gonadal characteristics of bighead carp in the Missouri River. Adult bighead carp in our sample varied from age 3 to age 7 and length varied from 475 to 1050 mm. There was a large variation in length at age, and overall bighead carp exhibited fast growth. For example, mean back-calculated length at age 3 was 556 mm. The sample was dominated by bighead carp from the 1994 year class. There was no difference in gonad development (i.e., gonadal somatic index, egg diameter) between winter and spring samples. Length of male bighead carp and GSI were not significantly correlated; however, females exhibited a positive linear relationship between length and GSI. In each ovary, egg diameter frequencies exhibited a bimodal distribution, indicating protracted spawning. Mean fecundity was 226 213, with a maximum fecundity of 769 964. Bighead carp in the Missouri River have similar life history characteristics to Asian and European populations. They have become well established in the Missouri River and it is likely that dispersal and population density will increase.

  4. Age and growth of the walleye in Lake Erie, 1963-1968

    USGS Publications Warehouse

    Wolfert, David R.

    1977-01-01

    Age and length distributions are given for 6,764 walleyes, Stizostedion v. vitreum (Mitchill), sampled during 1963-1968 from commercial landings of walleyes representing discrete populations in the eastern and western basins of Lake Erie. In the eastern basin, where all catches were made with gill nets, age-groups III and IV predominated in samples from large-mesh nets and age-group I in samples from small-mesh nets. In the western basin, where nearly all walleyes were taken in trap nets, age-groups I and II predominated in 1963-1965, and II and III in 1966-1968 (after the legal commercial size limit was raised from 330 to 394 mm). Study of 5,082 walleyes from the two basins showed that at any given age during the first 3 years of life, females were longer than males and, on the average, fish from the western basin were longer than those from the eastern basin. The greatest difference in growth of fish of the same sex for the two basins was apparent at the end of the first year of life, when fish from the eastern basin were only about half as heavy as those from the western basin. After the second year, relative growth in weight of fish in the eastern basin improved: the weight of females exceeded that of females in the western basin by the end of the fourth growing season and the weights of males in the two basins were about equal by the end of the sixth growing season.

  5. Drosophila Fip200 is an essential regulator of autophagy that attenuates both growth and aging

    PubMed Central

    Kim, Myungjin; Park, Hae Li; Park, Hwan-Woo; Ro, Seung-Hyun; Nam, Samuel G.; Reed, John M.; Guan, Jun-Lin; Lee, Jun Hee

    2013-01-01

    Autophagy-related 1 (Atg1)/Unc-51-like protein kinases (ULKs) are evolutionarily conserved proteins that play critical physiological roles in controlling autophagy, cell growth and neurodevelopment. RB1-inducible coiled-coil 1 (RB1CC1), also known as PTK2/FAK family-interacting protein of 200 kDa (FIP200) is a recently discovered binding partner of ULK1. Here we isolated the Drosophila RB1CC1/FIP200 homolog (Fip200/CG1347) and showed that it mediates Atg1-induced autophagy as a genetically downstream component in diverse physiological contexts. Fip200 loss-of-function mutants experienced severe mobility loss associated with neuronal autophagy defects and neurodegeneration. The Fip200 mutants were also devoid of both developmental and starvation-induced autophagy in salivary gland and fat body, while having no defects in axonal transport and projection in developing neurons. Interestingly, moderate downregulation of Fip200 accelerated both developmental growth and aging, accompanied by target of rapamycin (Tor) signaling upregulation. These results suggest that Fip200 is a critical downstream component of Atg1 and specifically mediates Atg1’s autophagy-, aging- and growth-regulating functions. PMID:23819996

  6. New insights on Antarctic gorgonians' age, growth and their potential as paleorecords

    NASA Astrophysics Data System (ADS)

    Martinez-Dios, Ariadna; Dominguez-Carrió, Carlos; Zapata-Guardiola, Rebeca; Gili, Josep-Maria

    2016-06-01

    Antarctic benthic communities have long been regarded as relicts of the past, since they have developed in a very stable environment and are formed by slow-growing and extraordinary long-lived organisms. However, little is known about the life history traits of gorgonian species, which are considered key components of the Antarctic benthos. In this study, age, Radial Growth Rates (RGR) and skeletal composition of Thouarella variabilis, Fannyella abies and Fannyella rossii colonies (Octocorallia, Primnoidae) that inhabit Antarctic shelf waters were examined. The radioisotopes 14C and 210Pb used for dating revealed that these colonies are long-lived, with ages spanning from 50 to 1100 years, thus confirming the archaic character of the Antarctic ecosystem. Some RGR obtained are among the lowest rates ever reported for primnoid species and gorgonians as a whole, with Thouarella species showing rates of 5.08 μm yr-1. Growth ring deposition seemed to occur every 2-3 years on average, although this result cannot be confirmed. Irregularities in the growth rings could be observed under the Scanning Electron Microscope (SEM) as fluctuations in the skeletal composition, which may be indicative of changes in the environmental conditions, most possibly primary production.

  7. Urban groundwater age modeling under unconfined condition - Impact of underground structures on groundwater age: Evidence of a piston effect

    NASA Astrophysics Data System (ADS)

    Attard, Guillaume; Rossier, Yvan; Eisenlohr, Laurent

    2016-04-01

    In this paper, underground structures are shown to have a major influence on the groundwater mean age distribution described as a dispersive piston effect. Urban underground development does not occur without impacts on subsoil resources. In particular, groundwater resources can be vulnerable and generate disturbances when this space is exploited. Groundwater age spatial distribution data are fundamental for resource management as it can provide operational sustainability indicators. However, the application of groundwater age modeling is neglected regarding the potential effect of underground structures in urban areas. A three dimensional modeling approach was conducted to quantify the impact of two underground structures: (1) an impervious structure and (2) a draining structure. Both structures are shown to cause significant mixing processes occurring between shallow and deeper aquifers. The design technique used for draining structures is shown to have the greatest impact, generating a decrease in mean age of more than 80% under the structure. Groundwater age modeling is shown to be relevant for highlighting the role played by underground structures in advective-dispersive flows in urban areas.

  8. 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.

  9. Protocols and programs for high-throughput growth and aging phenotyping in yeast.

    PubMed

    Jung, Paul P; Christian, Nils; Kay, Daniel P; Skupin, Alexander; Linster, Carole L

    2015-01-01

    In microorganisms, and more particularly in yeasts, a standard phenotyping approach consists in the analysis of fitness by growth rate determination in different conditions. One growth assay that combines high throughput with high resolution involves the generation of growth curves from 96-well plate microcultivations in thermostated and shaking plate readers. To push the throughput of this method to the next level, we have adapted it in this study to the use of 384-well plates. The values of the extracted growth parameters (lag time, doubling time and yield of biomass) correlated well between experiments carried out in 384-well plates as compared to 96-well plates or batch cultures, validating the higher-throughput approach for phenotypic screens. The method is not restricted to the use of the budding yeast Saccharomyces cerevisiae, as shown by consistent results for other species selected from the Hemiascomycete class. Furthermore, we used the 384-well plate microcultivations to develop and validate a higher-throughput assay for yeast Chronological Life Span (CLS), a parameter that is still commonly determined by a cumbersome method based on counting "Colony Forming Units". To accelerate analysis of the large datasets generated by the described growth and aging assays, we developed the freely available software tools GATHODE and CATHODE. These tools allow for semi-automatic determination of growth parameters and CLS behavior from typical plate reader output files. The described protocols and programs will increase the time- and cost-efficiency of a number of yeast-based systems genetics experiments as well as various types of screens. PMID:25822370

  10. Protocols and Programs for High-Throughput Growth and Aging Phenotyping in Yeast

    PubMed Central

    Jung, Paul P.; Christian, Nils; Kay, Daniel P.; Skupin, Alexander; Linster, Carole L.

    2015-01-01

    In microorganisms, and more particularly in yeasts, a standard phenotyping approach consists in the analysis of fitness by growth rate determination in different conditions. One growth assay that combines high throughput with high resolution involves the generation of growth curves from 96-well plate microcultivations in thermostated and shaking plate readers. To push the throughput of this method to the next level, we have adapted it in this study to the use of 384-well plates. The values of the extracted growth parameters (lag time, doubling time and yield of biomass) correlated well between experiments carried out in 384-well plates as compared to 96-well plates or batch cultures, validating the higher-throughput approach for phenotypic screens. The method is not restricted to the use of the budding yeast Saccharomyces cerevisiae, as shown by consistent results for other species selected from the Hemiascomycete class. Furthermore, we used the 384-well plate microcultivations to develop and validate a higher-throughput assay for yeast Chronological Life Span (CLS), a parameter that is still commonly determined by a cumbersome method based on counting “Colony Forming Units”. To accelerate analysis of the large datasets generated by the described growth and aging assays, we developed the freely available software tools GATHODE and CATHODE. These tools allow for semi-automatic determination of growth parameters and CLS behavior from typical plate reader output files. The described protocols and programs will increase the time- and cost-efficiency of a number of yeast-based systems genetics experiments as well as various types of screens. PMID:25822370

  11. Jatropha curcas L. Root Structure and Growth in Diverse Soils

    PubMed Central

    Valdés-Rodríguez, Ofelia Andrea; Sánchez-Sánchez, Odilón; Pérez-Vázquez, Arturo; Caplan, Joshua S.; Danjon, Frédéric

    2013-01-01

    Unlike most biofuel species, Jatropha curcas has promise for use in marginal lands, but it may serve an additional role by stabilizing soils. We evaluated the growth and structural responsiveness of young J. curcas plants to diverse soil conditions. Soils included a sand, a sandy-loam, and a clay-loam from eastern Mexico. Growth and structural parameters were analyzed for shoots and roots, although the focus was the plasticity of the primary root system architecture (the taproot and four lateral roots). The sandy soil reduced the growth of both shoot and root systems significantly more than sandy-loam or clay-loam soils; there was particularly high plasticity in root and shoot thickness, as well as shoot length. However, the architecture of the primary root system did not vary with soil type; the departure of the primary root system from an index of perfect symmetry was 14 ± 5% (mean ± standard deviation). Although J. curcas developed more extensively in the sandy-loam and clay-loam soils than in sandy soil, it maintained a consistent root to shoot ratio and root system architecture across all types of soil. This strong genetic determination would make the species useful for soil stabilization purposes, even while being cultivated primarily for seed oil. PMID:23844412

  12. The growth of structure in interacting dark energy models

    SciTech Connect

    Caldera-Cabral, Gabriela; Maartens, Roy; Schaefer, Bjoern Malte E-mail: roy.maartens@port.ac.uk

    2009-07-01

    If dark energy interacts with dark matter, there is a change in the background evolution of the universe, since the dark matter density no longer evolves as a{sup −3}. In addition, the non-gravitational interaction affects the growth of structure. In principle, these changes allow us to detect and constrain an interaction in the dark sector. Here we investigate the growth factor and the weak lensing signal for a new class of interacting dark energy models. In these models, the interaction generalises the simple cases where one dark fluid decays into the other. In order to calculate the effect on structure formation, we perform a careful analysis of the perturbed interaction and its effect on peculiar velocities. Assuming a normalization to today's values of dark matter density and overdensity, the signal of the interaction is an enhancement (suppression) of both the growth factor and the lensing power, when the energy transfer in the background is from dark matter to dark energy (dark energy to dark matter)

  13. Jatropha curcas L. root structure and growth in diverse soils.

    PubMed

    Valdés-Rodríguez, Ofelia Andrea; Sánchez-Sánchez, Odilón; Pérez-Vázquez, Arturo; Caplan, Joshua S; Danjon, Frédéric

    2013-01-01

    Unlike most biofuel species, Jatropha curcas has promise for use in marginal lands, but it may serve an additional role by stabilizing soils. We evaluated the growth and structural responsiveness of young J. curcas plants to diverse soil conditions. Soils included a sand, a sandy-loam, and a clay-loam from eastern Mexico. Growth and structural parameters were analyzed for shoots and roots, although the focus was the plasticity of the primary root system architecture (the taproot and four lateral roots). The sandy soil reduced the growth of both shoot and root systems significantly more than sandy-loam or clay-loam soils; there was particularly high plasticity in root and shoot thickness, as well as shoot length. However, the architecture of the primary root system did not vary with soil type; the departure of the primary root system from an index of perfect symmetry was 14 ± 5% (mean ± standard deviation). Although J. curcas developed more extensively in the sandy-loam and clay-loam soils than in sandy soil, it maintained a consistent root to shoot ratio and root system architecture across all types of soil. This strong genetic determination would make the species useful for soil stabilization purposes, even while being cultivated primarily for seed oil. PMID:23844412

  14. Growth in the intersection of eHealth and active and healthy ageing.

    PubMed

    Dimitrova, Rostislava

    2013-01-01

    Growth and growth enhancing policies are among the top priorities of the EU policy agenda to overcome mounting budgetary, economic and societal challenges, e.g. demographic change. The Europe 2020 strategy aims to coordinate and support actions at European, national and regional level to enhance smart, sustainable and inclusive growth. By developing the European Innovation Partnership for active and healthy ageing, the Commission aimed at fostering innovation as a way of reaching the goal of increasing Healthy Life Years (HLY) by 2 years on average across the EU Member States. The goal is a triple win for Europe: better health and independent living for elderly citizens, sustainable health systems and a competitive market of innovative products responding to elderly needs. eHealth plays an important role in reaching this objectives. The EIP policy aims to bring together stakeholders to remove barriers for the uptake of eHealth innovation and growth of eHealth markets, developing or rolling out sustainable business models of eHealth and telemedicine, exploring innovative funding mechanisms, e.g. PPPs, improving interoperability and ending market fragmentation. To improve interoperability between electronic health systems and maximise social and economic benefits of eHealth is also the main objective of the new eHealth Network (Directive 2001/24/EU) - a voluntary network of national authorities responsible for eHealth, which all EU Member states have joined. PMID:23510978

  15. Aging in K1-xLixTaO3: A Domain Growth Interpretation

    NASA Astrophysics Data System (ADS)

    Alberici-Kious, F.; Bouchaud, J. P.; Cugliandolo, L. F.; Doussineau, P.; Levelut, A.

    1998-11-01

    The aging behavior of the ac susceptibility of randomly substituted K1-xLixTaO3 crystals reveals marked differences with spin glasses in that cooling rate effects are very important. The response to temperature steps (including temperature cycles) was carefully studied. A model based on thermally activated domain growth accounts for all the experimental results, provided one allows for a large distribution of pinning energies, in such a way that ``slow'' and ``fast'' domains coexist. Interesting similarities with deeply supercooled liquids are underlined.

  16. Growth Rate and Relocation Movements of Common Nighthawk (Chordeiles minor) Nestlings in Relation to Age

    USGS Publications Warehouse

    Kramer, Gunnar R.; Chalfoun, Anna D.

    2012-01-01

    Relocation by dependent young is a survival strategy that occurs among a wide range of taxa. The Common Nighthawk (Chordeiles minor) lays its eggs on bare substrate and, once hatched, nestlings may relocate to new sites daily. We located and monitored eight Common Nighthawk nests in Grand Teton National Park, Wyoming, quantified inter-use-site distances in relation to nestling age, and calculated a nestling growth rate curve. Common Nighthawk nestlings grow in a nearly linear fashion. Nestlings moved up to 48 m in a single day and larger, older nestlings tended to move greater distances between daily use-sites.

  17. 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.

  18. Age- and sex-associated plasma proteomic changes in growth hormone receptor gene-disrupted mice.

    PubMed

    Ding, Juan; Berryman, Darlene E; Jara, Adam; Kopchick, John J

    2012-08-01

    Growth hormone receptor gene-disrupted (GHR-/-) mice are dwarf, insulin sensitive, and long lived despite being obese. In order to identify characteristics associated with their increased longevity, we studied age-related plasma proteomic changes in these mice. Male and female GHR-/- mice and their littermate controls were followed longitudinally at 8, 16, and 24 months of ages for plasma proteomic analysis. Relative to control littermates, GHR-/- mice had increased levels of apolipoprotein A-4 and retinol-binding protein-4 and decreased levels of apolipoprotein E, haptoglobin, and mannose-binding protein-C. Female GHR-/- mice showed decreased inflammatory cytokines including interleukin-1β and monocyte chemotactic protein-1. Additionally, sex differences were found in specific isoforms of apolipoprotein E, RBP-4, haptoglobin, albumin, and hemoglobin subunit beta. In conclusion, we find plasma proteomic changes in GHR-/- mice that favor a longer life span as well as sex differences indicative of an improved health span in female mice. PMID:22156438

  19. 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.

  20. Cortical neurons express nerve growth factor receptors in advanced age and Alzheimer disease.

    PubMed Central

    Mufson, E J; Kordower, J H

    1992-01-01

    Using a monoclonal antibody directed against the primate nerve growth factor (NGF) receptor, we examined the expression of NGF receptors within neuronal perikarya of normal adult human cerebral cortex (27-98 years old) and individuals with Alzheimer disease (AD). This expression of cortical NGF receptors was compared with that seen in other neurological diseases and normal human development as well as in young and aged nonhuman primates. NGF receptor-containing cortical neurons were not observed in young adults (less than 50 years old) and were observed only infrequently in non-demented elderly individuals (50-80 years old). In contrast, numerous NGF receptor-containing cortical neurons were seen in AD patients of all ages and in one 98-year-old nondemented patient. In advanced age and AD, numerous NGF receptor-positive neurons were located within laminae II-VI of temporal association cortices whereas only a few were seen in the subicular complex, entorhinal cortex, parahippocampal gyrus, and amygdaloid complex. These perikarya appeared healthy, with bipolar, fusiform, or multipolar morphologies and extended varicose dendritic arbors. These neurons failed to express neurofibrillary tangle-bearing material. In contrast to AD, NGF receptor-containing cortical neurons were not observed in Parkinson disease, Pick disease, or Shy-Drager syndrome. The NGF receptor-containing cortical neurons seen in advanced age and AD were similar in morphology to those observed in human fetal cortex. No NGF receptor-containing cortical neurons were observed in young or aged nonhuman primates. These findings suggest that neurons within the human cerebral cortex exhibit plasticity in their expression of NGF receptors in AD and extreme advanced aging. Images PMID:1309947

  1. Age, growth, and natural mortality of yellowfin grouper (Mycteroperca venenosa) from the southeastern United States

    PubMed Central

    Potts, Jennifer C.; Carr, Daniel R.

    2015-01-01

    Ages of yellowfin grouper (n = 306) from the southeastern United States coast from 1979–2014 were determined using sectioned sagittal otoliths. Opaque zones were annular, forming January–June (peaking in February–March). Yellowfin grouper ranged in age from 3 to 31 years; the largest fish measured 1,000 mm fork length (FL). Body size relationships for yellowfin grouper were: W = 1.22 × 10−5 FL3.03 (n = 229, r2 = 0.92); TL = 1.06 FL − 14.53 (n = 60, r2 = 0.99); and FL = 0.93 TL + 18.63 (n = 60, r2 = 0.99), where W = whole weight in grams, FL in mm, and TL = total length in mm. The von Bertalanffy growth equation was: Lt = 958 (1 − e−0.11(t+2.94)) (n = 306). The point estimate of natural mortality for yellowfin grouper was M = 0.14, while age-specific estimates of M ranged from 1.59 to 0.17 for ages 1–31. PMID:26244111

  2. Aging formula for lithium ion batteries with solid electrolyte interphase layer growth

    NASA Astrophysics Data System (ADS)

    Tanim, Tanvir R.; Rahn, Christopher D.

    2015-10-01

    Hybrid Electric Vehicle (HEV) current profiles are dynamic, consisting of repeated charge and discharge pulses. Accurate prediction of the battery response to these inputs requires models with open circuit voltage and Butler-Volmer kinetic nonlinearities. This paper derives a nonlinear, electrolyte-enhanced, single particle model (NESPM) that includes aging due to solid electrolyte interphase layer growth. The model is validated with experimental full charge, discharge, HEV cycle, and aging data from 4.5 Ah graphite/LiFePO4 cells. The NESPM is capable of operating up to 3C constant charge-discharge cycles and up to 25C and 10 s charge-discharge pulses within 35-65% state of charge (SOC) with less than 2% error. The NESPM aging model is then simplified to obtain explicit formulas for capacity fade and impedance rise that depend on the battery parameters and current input history. The formulas show that aging increases with SOC, operating temperature, time, and root mean square (RMS) current. The formula predicts that HEV current profiles with the (i) same average SOC, (ii) small SOC swing, (iii) same operating temperature, (iv) same cycle length, and (v) same RMS current, will have the same cell capacity fade.

  3. Coming of leaf age: control of growth by hydraulics and metabolics during leaf ontogeny.

    PubMed

    Pantin, Florent; Simonneau, Thierry; Muller, Bertrand

    2012-10-01

    Leaf growth is the central process facilitating energy capture and plant performance. This is also one of the most sensitive processes to a wide range of abiotic stresses. Because hydraulics and metabolics are two major determinants of expansive growth (volumetric increase) and structural growth (dry matter increase), we review the interaction nodes between water and carbon. We detail the crosstalks between water and carbon transports, including the dual role of stomata and aquaporins in regulating water and carbon fluxes, the coupling between phloem and xylem, the interactions between leaf water relations and photosynthetic capacity, the links between Lockhart's hydromechanical model and carbon metabolism, and the central regulatory role of abscisic acid. Then, we argue that during leaf ontogeny, these interactions change dramatically because of uncoupled modifications between several anatomical and physiological features of the leaf. We conclude that the control of leaf growth switches from a metabolic to a hydromechanical limitation during the course of leaf ontogeny. Finally, we illustrate how taking leaf ontogeny into account provides insights into the mechanisms underlying leaf growth responses to abiotic stresses that affect water and carbon relations, such as elevated CO2, low light, high temperature and drought. PMID:22924516

  4. Micro-structured surfaces for algal biofilm growth

    NASA Astrophysics Data System (ADS)

    Sathananthan, Suthamathy; Genin, Scott N.; Aitchison, J. Stewart; Allen, D. Grant

    2013-12-01

    It is well known that cells respond to structured surface cues that are on the micro/nanometer scale. Tissue engineering and bio-fouling fields have utilized the semiconductor device fabrication processes to make micro- and nanometer patterned surfaces to study animal cell tissue formation and to prevent algae attachment on marine surfaces respectively. In this paper we describe the use of micro-structured surfaces to study the attachment and growth of algal films. This paper gives an overview of how micro-structured surfaces are made for this purpose, how they are incorporated into a photo bioreactor and how this patterning influences the growth of an algal biofilm. Our results suggest that surface patterning with deeper V-groove patterns that are of the same size scale as the algal species has resulted in higher biomass productivity giving them a chance to embed and attach on the slope and flat surfaces whereas shallower size grooves and completely flat surfaces did not show this trend.

  5. Modeling the initiation and growth of delaminations in composite structures

    SciTech Connect

    Reedy, E.D. Jr.; Mello, F.J.; Guess, T.R.

    1996-01-01

    A method for modeling the initiation and growth of discrete delaminations in shell-like composite structures is presented. The laminate is divided into two or more sublaminates, with each sublaminate modeled with 4-noded quadrilateral shell elements. A special, 8-noded hex constraint element connects the sublaminates and makes them act as a single laminate until a prescribed failure criterion is attained. When the failure criterion is reached, the connection is broken, and a discrete delamination is initiated or grows. This approach has been implemented in a three-dimensional, finite element code. This code uses explicit time integration, and can analyze shell-like structures subjected to large deformations and complex contact conditions. Tensile, compressive, and shear laminate failures are also modeled. This paper describes the 8-noded hex constraint element used to model the initiation and growth of a delamination, and discusses associated implementation issues. In addition, calculated results for double cantilever beam and end notched flexure specimens are presented and compared to measured data to assess the ability of the present approach to reproduce observed behavior. Results are also presented for a diametrally compressed ring to demonstrate the capacity to analyze progressive failure in a highly deformed composite structure.

  6. Sensitivity analysis of the age-structured malaria transmission model

    NASA Astrophysics Data System (ADS)

    Addawe, Joel M.; Lope, Jose Ernie C.

    2012-09-01

    We propose an age-structured malaria transmission model and perform sensitivity analyses to determine the relative importance of model parameters to disease transmission. We subdivide the human population into two: preschool humans (below 5 years) and the rest of the human population (above 5 years). We then consider two sets of baseline parameters, one for areas of high transmission and the other for areas of low transmission. We compute the sensitivity indices of the reproductive number and the endemic equilibrium point with respect to the two sets of baseline parameters. Our simulations reveal that in areas of either high or low transmission, the reproductive number is most sensitive to the number of bites by a female mosquito on the rest of the human population. For areas of low transmission, we find that the equilibrium proportion of infectious pre-school humans is most sensitive to the number of bites by a female mosquito. For the rest of the human population it is most sensitive to the rate of acquiring temporary immunity. In areas of high transmission, the equilibrium proportion of infectious pre-school humans and the rest of the human population are both most sensitive to the birth rate of humans. This suggests that strategies that target the mosquito biting rate on pre-school humans and those that shortens the time in acquiring immunity can be successful in preventing the spread of malaria.

  7. 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.

  8. Growth Simulation and Structure Analysis of Obliquely Deposited Thin Films

    NASA Astrophysics Data System (ADS)

    Belyaev, B. A.; Izotov, A. V.; Solovev, P. N.

    2016-06-01

    Based on the Monte Carlo method, a model of growth of thin films prepared by oblique angle deposition of particles is constructed. The morphology of structures synthesized by simulation is analyzed. To study the character of distribution of microstructural elements (columns) in the film plane, the autocorrelation function of the microstructure and the fast Fourier transform are used. It is shown that with increasing angle of particle incidence, the film density monotonically decreases; in this case, anisotropy arises and monotonically increases in the cross sections of columns, and the anisotropy of distribution of columns in the substrate plane also increases.

  9. Family Structure and the Timing of Transitions from 70 to 103 Years of Age.

    ERIC Educational Resources Information Center

    Johnson, Colleen L.; Troll, Lillian

    1996-01-01

    Using a cross-sectional analysis of 250 white individuals, 70-103 years of age, this article questions whether a vertical family structure is found with increasing age. Findings indicate, among other things, that at least until age 90 the proportion of individuals with a vertical family structure with four generations never exceeds the numbers of…

  10. Age, growth, maturity, and fecundity of 'humper' lake trout, Isle Royale, Lake Superior

    USGS Publications Warehouse

    Rahrer, Jerold F.

    1965-01-01

    Humper lake trout are one of the several races or subpopulations of lake trout in Lake Superior. This study is based on 3,705 fish collected on a reef south of Isle Royale near the eastern end. The mean lengths of humper trout from commercial gill nets were smaller than those of lean lake trout. Members of age-groups VII, VIII, and IX represented 81.5 per cent of the commercial humper catch. The body-scale relation was described by two intersecting straight lines. The weight of humper trout increased as the 3.282 power of the length. Growth in length was slow and ranged from 1.6 to 3.5 inches per year. Annual increments were greatest in the first, sixth, and seventh years. Growth in weight was also slow but increased each year. Humper trout became legal (1 1/2 pounds) in the eighth year of life and reached 5 pounds in 11 years. All fish longer than 19.1 inches and older than age-group VIII were mature; the shortest mature fish were: males, 12.7 inches; females, 14.7 inches. At minimum legal size, 98 per cent of the males and 56 per cent of the females were mature. Humper trout produced an average of 1,351 eggs per fish or 516 per pound.

  11. Age and Growth of the Round Stingray Urotrygon rogersi, a Particularly Fast-Growing and Short-Lived Elasmobranch

    PubMed Central

    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. PMID:24776963

  12. Growth failure starts from early infancy in children with short stature at age 6

    PubMed Central

    Noda, Masahiro; Sato, Naoko; Tanaka, Toshiaki

    2015-01-01

    Abstract We compared the growth of 183 children with short stature (≤ 2SD) and 73 children of normal height at age six who were visiting the Tanaka Growth Clinic. We classified these short children as suffering from either idiopathic short stature (ISS, n = 119), GH deficiency (GHD, n = 33) or small-for-gestational-age short stature (SGASS, n = 31) on the basis of subsequent test results and other factors. We also conducted a retrospective study of changes in their height, wt and nutritional intake over time. The mean changes in height SD score from birth to 6 yr were –0.24 SD in normal height children with a normal birth length and +2.27 SD in normal height children with a low birth length. In short children, these changes were –1.93 SD for children with ISS, –2.41 SD for those with GHD and +0.58 for those with SGASS. The mean changes from birth to 6 mo were –0.84 SD, −1.03 SD and +0.38 SD in children with ISS, GHD and SGASS, respectively. The mean change in height SD score from birth to age 1 yr was –1.07 SD, –1.44 SD and +0.35 SD, respectively. The decrease in height SD score from birth to 6 mo accounted for 43.5% of the decrease in height SD score from birth to 6 yr in children with ISS and it accounted for 42.6% of the decrease in children with GHD. Only 19% of short children bottle-fed well, and 53% fed poorly, as opposed to 56% and 16% of normal height children who fed well and poorly, respectively. Post weaning, only 22% of short children ate well, and 56% fed poorly, as opposed to 53% and 17% of normal height children who fed well and poorly, respectively. These findings demonstrated that growth failure started from early infancy in ISS and GHD children. It was suggested that poor nutritional intake in infancy and early childhood was a partial cause of short stature at age 6. PMID:25678754

  13. Zinc supplementation and growth of infants born small for gestational age.

    PubMed

    Castillo-Durán, C; Rodríguez, A; Venegas, G; Alvarez, P; Icaza, G

    1995-08-01

    To analyze the effect of zinc supplementation on postnatal growth of infants born small for gestational age, we selected 68 infants at birth and followed them monthly for 6 months. They were randomly assigned to a supplemented group (group S, n = 35) receiving 3 mg of Zn (acetate) per day, or to a placebo (group P, n = 33), in a double-blind study. Weight increments in group S were significantly higher than those in group P at 2 months (p < 0.003); z scores showed catch-up growth only in group S. Length increments were also greater in group S than in group P, ending at 6 months were 64.9 +/- 1.8 versus 63.4 +/- 3.5 cm (mean +/- SD; p < 0.01); changes in z scores for 6 months were -1.28 to -0.66 in group S and -1.43 to -1.47 in group P (p < 0.001). Weight-for-length improved similarly in both groups (z score, -2.2 to +0.2). The increase in weight-for-age was higher in group S girls (p < 0.034), ending at 6 months with -0.13 +/- 0.59, versus -0.52 +/- 0.62 in group S boys, -1.15 +/- 0.49 in group P girls, and -1.05 +/- 0.80 in group P boys (+/- SD). More infants in group P received cow milk-based formula before 4 months because of inadequate weight increments. An additive effect on weight increase was observed between Zn supplementation (p < 0.02), exclusive breast-feeding after 4 months of age (p < 0.001), and gender (p < 0.02). Plasma and hair Zn values showed a downward trend, less marked in group S than in group P. We conclude that Chilean infants born small for gestational age have better weight and linear growth during the first 6 months of life if they receive Zn supplementation. PMID:7636643

  14. Age, growth, and maturity of the longnose sucker Catostomus catostomus, of western Lake Superior

    USGS Publications Warehouse

    Bailey, Merryll M.

    1969-01-01

    Studies of age, growth, and maturity were based on 1760 fish collected in western Lake Superior in 1964-65. The body:scale relation was curvilinear and the curve had an intercept of 1.65 inches on the length axis. The weight increased as the 2.85 power of the length. Some fish formed an annulus before May 18 in 1965; all had completed annuli by late September. Longnose suckers grew 3.6 inches the 1st year, reached 12 inches in the 6th year, and 18 inches in the 11th year. Fish from Pikes Bay grew faster than those from Gull Island Shoal. Over 6 years were required for weight to reach 1 lb and nearly 10 years to reach 2 lb. Minimum length at maturity was 10.5 inches for males and 11.5 inches for females. The youngest mature male belonged to age-group IV and the youngest mature female to age-group V. All males were mature at 14.5-14.9 inches (age-group VIII) and all females at 15.0-15.4 inches (age-group IX). Finclipped longnose suckers returned to spawn in the Brule River in successive years. One fish returned to spawn in 4 successive years. Many of the fish were not recaptured until 2 or 3 years after marking. The time of the Brule River spawning migration depended more on water temperature than on length of day. The average water temperature during the peak of the spawning runs of 1958-64 was 55.4 F. Larval suckers apparently spend little time in the Brule River and adjacent streams and drift downstream to the lake soon after hatching. The number of eggs in the ovaries of eight suckers ranged from 14 to 35 thousand and averaged 24 thousand for fish 13.9-17.7 inches long.

  15. Morphological and Structural Investigation of Sexithiophene Growth on KCl (100)

    PubMed Central

    2012-01-01

    The morphology and structure of sexithiophene deposited on KCl (100) substrates was investigated by scanning force microscopy and specular X-ray diffraction measurements. Two different needle-like structures with {010} and {4̅11} contact planes have been observed as well as islands of almost upright standing sexithiophene molecules with a {100} contact plane. Furthermore an azimuthal alignment of all three crystal orientations was observed by X-ray diffraction pole figure measurements, and the growth directions reflect the 4-fold rotational symmetry of the substrate surface. In addition the analysis of crystals with {4̅11} and {100} contact planes unveiled that they share a common crystallographic direction which is explained by ledge directed epitaxy. PMID:23413362

  16. Atomic and electronic structure of twin growth defects in magnetite

    PubMed Central

    Gilks, Daniel; Nedelkoski, Zlatko; Lari, Leonardo; Kuerbanjiang, Balati; Matsuzaki, Kosuke; Susaki, Tomofumi; Kepaptsoglou, Demie; Ramasse, Quentin; Evans, Richard; McKenna, Keith; Lazarov, Vlado K.

    2016-01-01

    We report the existence of a stable twin defect in Fe3O4 thin films. By using aberration corrected scanning transmission electron microscopy and spectroscopy the atomic structure of the twin boundary has been determined. The boundary is confined to the (111) growth plane and it is non-stoichiometric due to a missing Fe octahedral plane. By first principles calculations we show that the local atomic structural configuration of the twin boundary does not change the nature of the superexchange interactions between the two Fe sublattices across the twin grain boundary. Besides decreasing the half-metallic band gap at the boundary the altered atomic stacking at the boundary does not change the overall ferromagnetic (FM) coupling between the grains. PMID:26876049

  17. On the bubble? With healthcare job growth outstripping population in aging Rust Belt cities, some question the trend's durability.

    PubMed

    Carlson, Joe; Kutscher, Beth

    2013-03-01

    Aging Rust Belt cities are some of the leaders in healthcare job growth despite stagnant or decreasing populations, even amid mounting pressure to cut healthcare costs. Areas seeing rapid population growth aren't as dependent on healthcare. "Cities that are growing quickly are most likely adding diversified industries," says Dr. Sheldon Retchin, of the Virginia Commonwealth University Health System. PMID:23516730

  18. The Effect of Age at Cochlear Implant Initial Stimulation on Expressive Language Growth in Infants and Toddlers

    ERIC Educational Resources Information Center

    Tomblin, J. Bruce; Barker, Brittan A.; Spencer, Linda J.; Zhang, Xuyang; Gantz, Bruce J.

    2005-01-01

    This study examined the growth of expressive language skills in children who received cochlear implants (CIs) in infancy. Repeated language measures were gathered from 29 children who received CIs between 10 and 40 months of age. Both cross-sectional and growth curve analyses were used to assess the relationship between expressive language…

  19. 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.)…

  20. Age-dependent capacity to accelerate protein synthesis dictates the extent of compensatory growth in skeletal muscle following undernutrition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In both humans and animals, impaired growth during early life compromises adult lean body mass and muscle strength despite skeletal muscle’s large regenerative capacity. To identify the significance of developmental age on skeletal muscle’s capacity for catch-up growth following an episode of under ...

  1. Research and Development of Individual Growth and Development Indicators for Children between Birth to Age Eight. Technical Report #4.

    ERIC Educational Resources Information Center

    McConnell, Scott; McEvoy, Mary; Carta, Judith J.; Greenwood, Charles R.; Kaminski, Ruth; Good, Roland H., III; Shinn, Mark

    This document provides an overview of the rationale for, and characteristics of, individual growth and development indicators (IGDIs) for children birth to age 8 and their families. Development of such indicators is part of a 5-year project by the Early Childhood Research Institute Measuring Growth and Development to conduct research on, develop,…

  2. Age, growth, and production of the yellow perch, Perca flavescens (Mitchill), of Saginaw Bay

    USGS Publications Warehouse

    Hile, Ralph; Jobes, Frank W.

    1941-01-01

    Ages were determined and individual growth histories computed from the examination and measurement of scales from 820 yellow perch collected in 1929 and 1930. Calculated lengths greater than 101 millimeters were computed on the assumption (supported by empirical data) that the ratio of body length to scale length is constant. Lengths below 101 millimeters were determined with the aid of an empirical curve of the body-scale relationship of small fish. Yellow perch of age-groups III and IV (in the fourth and fifth years of life) made up the bulk of the collection (78 per cent). Females grew slightly more rapidly than males, but members of both sexes attained the legal length of 8 1/2 inches during the fourth year of life, just as they were entering on the period of most rapid growth in weight. The greatest growth in weight of both sexes occurred in the sixth year of life. In the combined samples of the two years the females exceeded the males in abundance in the ratio, 296:100. The weight of the Saginaw Bay yellow perch was found to increase as the 3.117 power of the length. The relative length of the tail decreased with increase in the length of the fish. The Saginaw Bay yellow perch is now far less abundant than it was in the early years of the fishery. The average annual production of 548,000 pounds over the period, 1917-1938, was only 28 per cent of the earlier (1891-1916) "normal" annual production of 1,961,000 pounds. A detailed analysis of statistical data available for more recent years made possible a description of annual fluctuations in the abundance and production of yellow perch and in the intensity of the yellow perch fishery in Saginaw Bay over the period, 1929-1938.

  3. Asymmetric large-for-gestational-age infants of type 1 diabetic women: morbidity and abdominal growth.

    PubMed

    Bollepalli, Sureka; Dolan, Lawrence M; Miodovnik, Menachem; Feghali, Maisa; Khoury, Jane C

    2010-09-01

    We sought to examine neonatal morbidity in four groups of offspring (asymmetric large for gestational age [LGA], symmetric LGA, asymmetric non-LGA, symmetric non-LGA) exposed in utero to maternal type 1 diabetes, and the association between rate of fetal abdominal circumference growth and asymmetric LGA. We performed a secondary analysis of 302 singleton pregnancies. Neonatal morbidity (respiratory distress syndrome, polycythemia, hypoglycemia, hyperbilirubinemia, acidosis, and composite morbidity [any of the five]) was assessed. Serial ultrasound examinations after 20 weeks' gestation were available for 35 fetuses. Logistic regression and general linear mixed modeling were used for analysis. Asymmetric LGA infants had 3.5-, 2.2-, and 3.2-fold greater odds of hypoglycemia, hyperbilirubinemia, and composite morbidity, respectively, compared with symmetric non-LGA infants. The rate of growth of the abdominal circumference in asymmetric LGA infants (1.11 cm/wk) was greater than for both the symmetric LGA infants (0.87 cm/wk, P = 0.09) and the symmetric non-LGA infants (0.87 cm/wk, P = 0.03). Asymmetric LGA infants are at higher risk for morbidity than symmetric LGA and non-LGA infants. Intrauterine growth rate of the abdominal circumference may potentially be used as a marker to identify the asymmetric LGA and thereby aid in the identification of newborns at greatest risk for perinatal complications. PMID:20225174

  4. Catch-up growth and catch-up fat in children born small for gestational age

    PubMed Central

    Cho, Won Kyoung

    2016-01-01

    Infants born small for gestational age (SGA) are at increased risk of perinatal morbidity, persistent short stature, and metabolic alterations in later life. Recent studies have focused on the association between birth weight (BW) and later body composition. Some reports suggest that fetal nutrition, as reflected by BW, may have an inverse programing effect on abdominal adiposity later in life. This inverse association between BW and abdominal adiposity in adults may contribute to insulin resistance. Rapid weight gain during infancy in SGA children seemed to be associated with increased fat mass rather than lean mass. Early catch-up growth after SGA birth rather than SGA itself has been noted as a cardiovascular risk factor in later life. Children who are born SGA also have a predisposition to accumulation of fat mass, particularly intra-abdominal fat. It is not yet clear whether this predisposition is due to low BW itself, rapid postnatal catch-up growth, or a combination of both. In this report, we review the published literature on central fat accumulation and metabolic consequences of being SGA, as well as the currently popular research area of SGA, including growth aspects. PMID:26893597

  5. Growth marks observation: preferential techniques and teeth for ageing of Spanish red deer (Cervus elaphus hispanicus).

    PubMed

    Azorit, C; Analla, M; Hervas, J; Carrasco, R; Muñoz-Cobo, J

    2002-10-01

    A total of 207 teeth belonging to 53 deer (Cervus elaphus hispanicus) from Sierra Morena (South of Spain) were analysed using histological thin sections and/or polished thick sections. Growth marks were observed in dentine and cementum of incisors, molars and canines. Tooth, region of the tooth, and type of preparation giving the best performance in terms of sharpness and interpretation ease of the growth marks, when used for Spanish deer ageing, were identified. The tissue chosen for the study was the cellular cementum of the inter-radicular pad from molars and the acellular cementum of the root from incisors, both observed through longitudinal cuts. Histological sections obtained with a conventional microtome were optimal for a reliable identification of the first growth marks. In sections thicker than 15 microm the first rest line, when observed in cementum can be confused with the cementum-dentine junction; whereas in the polished sections from molars it will not appear at all. Dentine interpretation was more difficult. Its observation should only be accomplished using cross-sections of the molar root. Secondary or accessory marks were visible in every tooth, being those from the molar pad the easiest to distinguish. Canines were the less suitable teeth for this study. PMID:12484425

  6. Decorin expression is important for age-related changes in tendon structure and mechanical properties.

    PubMed

    Dunkman, Andrew A; Buckley, Mark R; Mienaltowski, Michael J; Adams, Sheila M; Thomas, Stephen J; Satchell, Lauren; Kumar, Akash; Pathmanathan, Lydia; Beason, David P; Iozzo, Renato V; Birk, David E; Soslowsky, Louis J

    2013-01-01

    The aging population is at an increased risk of tendon injury and tendinopathy. Elucidating the molecular basis of tendon aging is crucial to understanding the age-related changes in structure and function in this vulnerable tissue. In this study, the structural and functional features of tendon aging are investigated. In addition, the roles of decorin and biglycan in the aging process were analyzed using transgenic mice at both mature and aged time points. Our hypothesis is that the increase in tendon injuries in the aging population is the result of altered structural properties that reduce the biomechanical function of the tendon and consequently increase susceptibility to injury. Decorin and biglycan are important regulators of tendon structure and therefore, we further hypothesized that decreased function in aged tendons is partly the result of altered decorin and biglycan expression. Biomechanical analyses of mature (day 150) and aged (day 570) patellar tendons revealed deteriorating viscoelastic properties with age. Histology and polarized light microscopy demonstrated decreased cellularity, alterations in tenocyte shape, and reduced collagen fiber alignment in the aged tendons. Ultrastructural analysis of fibril diameter distributions indicated an altered distribution in aged tendons with an increase of large diameter fibrils. Aged wild type tendons maintained expression of decorin which was associated with the structural and functional changes seen in aged tendons. Aged patellar tendons exhibited altered and generally inferior properties across multiple assays. However, decorin-null tendons exhibited significantly decreased effects of aging compared to the other genotypes. The amelioration of the functional deficits seen in the absence of decorin in aged tendons was associated with altered tendon fibril structure. Fibril diameter distributions in the decorin-null aged tendons were comparable to those observed in the mature wild type tendon with the absence

  7. Decorin expression is important for age-related changes in tendon structure and mechanical properties

    PubMed Central

    Dunkman, Andrew A.; Buckley, Mark R.; Mienaltowski, Michael J.; Adams, Sheila M.; Thomas, Stephen J.; Satchell, Lauren; Kumar, Akash; Pathmanathan, Lydia; Beason, David P.; Iozzo, Renato V.; Birk, David E.; Soslowsky, Louis J.

    2013-01-01

    The aging population is at an increased risk of tendon injury and tendinopathy. Elucidating the molecular basis of tendon aging is crucial to understanding the age-related changes in structure and function in this vulnerable tissue. In this study, the structural and functional features of tendon aging are investigated. In addition, the roles of decorin and biglycan in the aging process were analyzed using transgenic mice at both mature and aged time points. Our hypothesis is that the increase in tendon injuries in the aging population is the result of altered structural properties that reduce the biomechanical function of the tendon and consequently increase susceptibility to injury. Decorin and biglycan are important regulators of tendon structure and therefore, we further hypothesized that decreased function in aged tendons is partly the result of altered decorin and biglycan expression. Biomechanical analyses of mature (day 150) and aged (day 570) patellar tendons revealed deteriorating viscoelastic properties with age. Histology and polarized light microscopy demonstrated decreased cellularity, alterations in tenocyte shape, and reduced collagen fiber alignment in the aged tendons. Ultrastructural analysis of fibril diameter distributions indicated an altered distribution in aged tendons with an increase of large diameter fibrils. Aged wild type tendons maintained expression of decorin which was associated with the structural and functional changes seen in aged tendons. Aged patellar tendons exhibited altered and generally inferior properties across multiple assays. However, decorin-null tendons exhibited significantly decreased effects of aging compared to the other genotypes. The amelioration of the functional deficits seen in the absence of decorin in aged tendons was associated with altered tendon fibril structure. Fibril diameter distributions in the decorin-null aged tendons were comparable to those observed in the mature wild type tendon with the absence

  8. On the growth and internal structure of the human lens

    PubMed Central

    Augusteyn, Robert C

    2010-01-01

    Growth of the human lens and the development of its internal features are examined using in vivo and in vitro observations on dimensions, weights, cell sizes, protein gradients and other properties. In vitro studies have shown that human lens growth is biphasic, asymptotic until just after birth and linear for most of postnatal life. This generates two distinct compartments, the prenatal and the postnatal. The prenatal growth mode leads to the formation of an adult nuclear core of fixed dimensions and the postnatal, to an ever-expanding cortex. The nuclear core and the cortex have different properties and can readily be physically separated. Communication and adhesion between the compartments is poor in older lenses. In vivo slit lamp examination reveals several zones of optical discontinuity in the lens. Different nomenclatures have been used to describe these, with the most common recognizing the embryonic, foetal, juvenile and adult nuclei as well as the cortex and outer cortex. Implicit in this nomenclature is the idea that the nuclear zones were generated at defined periods of development and growth. This review examines the relationship between the two compartments observed in vitro and the internal structures revealed by slit lamp photography. Defining the relationship is not as simple as it might seem because of remodeling and cell compaction which take place, mostly in the first 20 years of postnatal life. In addition, different investigators use different nomenclatures when describing the same regions of the lens. From a consideration of the dimensions, the dry mass contents and the protein distributions in the lens and in the various zones, it can be concluded that the juvenile nucleus and the layers contained within it, as well as most of the adult nucleus, were actually produced during prenatal life and the adult nucleus was completed within 3 months after birth, in the final stages of the prenatal growth mode. Further postnatal growth takes place

  9. Age, growth, and recruitment patterns of juvenile ladyfish (Elops sp) from the east coast of Florida (USA)

    PubMed Central

    2015-01-01

    Ladyfish (Elops sp) are a common and economically valuable coastal nearshore species found along coastal beaches, bays, and estuaries of the southeastern United States, and subtropical and tropical regions worldwide. Previously, ladyfish were a substantial bycatch in Florida’s commercial fisheries, but changes in regulations significantly reduced commercial landings. Today, ladyfish are still taken in commercial fisheries in Florida, but many are also taken by recreational anglers. Life-history information and research interest in ladyfish is almost non-existent, especially information on age and growth. Thus, the overarching purpose of this study was to expand our understanding of ladyfish age and growth characteristics. The specific objectives were to describe, for the first time, age, growth, and recruitment patterns of juvenile ladyfish from the east coast of Florida (USA). In the Indian River Lagoon (IRL), annual monthly length-frequency distributions were confounded because a few small individuals recruited throughout the year; monthly length-frequency data generally demonstrated a cyclical pattern. The smallest were collected in September and the largest in May. Post-hoc analysis showed no significant difference in length between August and May, or among the other months. In Volusia County (VC), annual monthly length-frequency distribution demonstrated growth generally occurred from late-winter and spring to summer. The smallest ladyfish were collected in February and the largest in August. On average, the absolute growth rate in the IRL was 36.3 mm in 60 days or 0.605 mm day−1. Cohort-specific daily growth rates, elevations, and coincidentals were similar among sampling years. Cohort-specific growth rates ranged from 1.807 in 1993 to 1.811 mm day−1 in 1994. Overall, growth was best (i.e., goodness of fit) described by exponential regression. On average, the absolute growth rate in VC was 28 mm in 150 days or 0.1866 mm day−1. Cohort-specific daily

  10. Plasma Astrophysics - Cosmology and the Growth of Cosmic Structure

    SciTech Connect

    Mushotzky, Richard

    2007-08-02

    I will present some of the ways that x-ray spectroscopy can be utilized to determine cosmological parameters focusing on 5 methods: the gas fraction in clusters, the use of the Sunyaev-Zeldovich effect, the detection of resonance scattering in clusters, the use of resonance absorption and emission in background sources and the growth of structure. All of these techniques except the S-Z effect rely heavily on high resolution x-ray spectroscopy and require the next generation of x-ray spectroscopic missions such as Constellation-X. The promise of these techniques is great and they have the potential for precision cosmology with errors similar to those of other precision techniques such as type Ia supernova. If time permits I will also talk about how we can learn about how active galaxies strongly influence the growth of cosmic structure and how broad band high resolution x-ray spectra are necessary to measure the effects of AGN and how much energy they input into the universe and the role of new atomic physics calculations in interpreting these results. A related discussion can be found in a previously published manuscript.

  11. Structural basis for agonism and antagonism of hepatocyte growth factor

    SciTech Connect

    Tolbert, W. David; Daugherty-Holtrop, Jennifer; Gherardi, Ermanno; Vande Woude, George; Xu, H. Eric

    2010-11-01

    Hepatocyte growth factor (HGF) is an activating ligand of the Met receptor tyrosine kinase, whose activity is essential for normal tissue development and organ regeneration but abnormal activation of Met has been implicated in growth, invasion, and metastasis of many types of solid tumors. HGF has two natural splice variants, NK1 and NK2, which contain the N-terminal domain (N) and the first kringle (K1) or the first two kringle domains of HGF. NK1, which is a Met agonist, forms a head-to-tail dimer complex in crystal structures and mutations in the NK1 dimer interface convert NK1 to a Met antagonist. In contrast, NK2 is a Met antagonist, capable of inhibiting HGF's activity in cell proliferation without clear mechanism. Here we report the crystal structure of NK2, which forms a 'closed' monomeric conformation through interdomain interactions between the N- domain and the second kringle domain (K2). Mutations that were designed to open up the NK2 closed conformation by disrupting the N/K2 interface convert NK2 from a Met antagonist to an agonist. Remarkably, this mutated NK2 agonist can be converted back to an antagonist by a mutation that disrupts the NK1/NK1 dimer interface. These results reveal the molecular determinants that regulate the agonist/antagonist properties of HGF NK2 and provide critical insights into the dimerization mechanism that regulates the Met receptor activation by HGF.

  12. The age, growth, and feeding habits of the whitefish Coregonus clupeaformis (Mitchell), of Lake Champlain

    USGS Publications Warehouse

    Van Oosten, John; Deason, Hilary J.

    1939-01-01

    This study is based on 120 whitefish collected in northern Lake Champlain (Missisquoi Bay) in 1930 and on 175 whitefish taken in southern Lake Champlain in 1931. Since the whitefish population had not been exploited commercially after 1912 in United States waters and after 1915 in Canadian waters, its study should be of interest in showing the characteristics of a population practically untouched by man. Data have been presented on length frequencies, age composition, growth, coefficient of condition, sex ratio, standard length-total length relationship, and feeding habits. The data indicated that the Missisquoi Bay population was disturbed (probably by the early fall seining of 1930) before our samples were taken so that the original length distributions no longer existed. The southern Lake Champlain material, however, showed a consistency which indicated that the population had not been exploited to any extensive degree, if at all. When the northern population was compared with the southern the former was found to differ from the latter in the following respects, which differences pointed to some disturbance of the northern stock in the lake 1. By possession of lower modes and smaller grand averages of length. 2. By absence of very old individuals. 3. By absence of a series of equally abundant age groups or, in other words, by the presence of a decided dominance of one or two age groups. 4. By a radical disagreement between the sexes in their age-frequency distribution. 5. By a disagreement between the sexes with respect to maximum lengths attained. All of the differences between the two collections could, however, not be attributed to exploitation. The following characteristics indicated the presence of two distinct populations in the lake 1. Presence of a spawning ground at each end of the lake. 2. Differences in calculated lengths and increments of length (growth rates). 3. Differences in the actual lengths and weights of corresponding age groups at capture. 4

  13. Growth, structure, and optical characterization of diluted magnetic semiconductor nanowires

    NASA Astrophysics Data System (ADS)

    Cooley, Benjamin Joseph

    Nanowires combining the usually disparate areas of semiconductors and magnetism are of contemporary relevance within the context of semiconductor spintronics. This is a relatively new field of research that seeks to exploit electron spin within electronic and opto-electronic semiconductor devices. While much of the effort within semiconductor spintronics has been directed toward fundamental studies and applications of 3D, 2D and 0D systems, there has been little work to date on 1D systems. The distinctive change in the electronic density of states with changing dimensionality provides a strong motivation for developing and exploring semiconductor nanowires in which one might be able to probe and control spin-dependent phenomena within a 1D or quasi-1D environment. This thesis explores the crystal growth, structural properties and magneto-optical behavior of quasi-1D semiconductor nanowires in which we incorporate magnetism through two approaches: first, by synthesizing nanowires of the diluted magnetic semiconductor (Zn,Mn)Se, wherein the d-shell electrons of substitutional Mn ions interact with the band states of the ZnSe host lattice via sp--d exchange; second, by making hybrid core-shell nanostructures wherein a metallic ferromagnetic shell (MnAs) is epitaxially deposited on a semiconductor nanowire (GaAs). After an introductory overview of past work in the field and a description of the experimental techniques relevant to the thesis, we discuss our experimental results. The first set of experiments focuses on ZnSe and (Zn,Mn)Se nanowires grown in a single stage. The nanowires were grown on Si and GaAs substrates with a thin layer of gold evaporated onto them, which were then annealed before growth so that the gold formed nanoscale droplets. The growth yields samples covered in random arrays of nanowires growing out an an angle to the substrate, with an undergrowth of crooked nanowires and other small structures. The long thin nanowires vary in diameter, down to

  14. Relationship between growth of facial morphology and chronologic age in preschool children with obstructive sleep apnea

    PubMed Central

    Kawashima, Shigeto; Ueda, Koichiro; Shinohara, Mitsuyo; Mano, Mikiko; Kanegae, Haruhide; Namaki, Shunsuke

    2012-01-01

    Background The purpose of this study was to evaluate the relationship between facial morphology using cephalometry and chronologic age in preschool children with obstructive sleep apnea (OSA). Materials and Methods From a group of lateral cephalometric radiographs taken of 35 children with OSA for diagnostic purposes, 15 were selected for the present investigation based on head position. The subjects consisted of preschool children with both OSA and primary dentition, all of them with a lowest documented SpO2 <90% and a lowest 0 age in the controls, there was no significant correlation between height, nasal floor length or corpus length with age in the OSA children. Conclusion Obstructive sleep apnea in children may be associated with growth disturbances of the nasal floor and corpus length. PMID:25756027

  15. Associations between genetic polymorphisms of insulin-like growth factor axis genes and risk for age-related macular degeneration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purpose: Our objective was to investigate if insulin-like growth factor (IGF) axis genes affect the risk for age-related macular degeneration (AMD). Methods: 864 Caucasian non-diabetic participants from the Age-Related Eye Disease Study (AREDS) Genetic Repository were used in this case control st...

  16. Growth increment periodicity in the shell of the razor clam Ensis directus using stable isotopes as a method to validate age

    NASA Astrophysics Data System (ADS)

    Cardoso, J. F. M. F.; Nieuwland, G.; Witbaard, R.; van der Veer, H. W.; Machado, J. P.

    2013-03-01

    To evaluate the role of the razor clam Ensis directus in Dutch coastal waters, assessment and understanding its population dynamics is important. As such, the age structure of the population forms a key parameter. Accurate age determination in bivalve shells is not always straightforward due to the difficulty of interpreting externally visible growth lines. In the present paper, we aimed at validating the seasonality in growth line formation using visual techniques in combination with stable oxygen and carbon isotope analyses (δ18O and δ13C). High δ18O values in the shell coincided with growth marks on the external surface of the valve and in acetate peels of the shell's cross section. Most shell δ18O samples were assigned to the months June to September. From November to March no samples were retrieved indicating that the shell did not grow. The lowest reconstructed temperature (6.1 °C) suggests that ~6 °C may be the threshold temperature for growth. Nevertheless, most of the reconstructed values fell above 14.5 °C indicating growth occurred mainly in the summer at relatively high temperatures. Shell δ13C profiles followed a more or less seasonal cycle but no direct relationship could be made between δ13C values and annual growth lines. Although counting external annual growth lines led to a correct estimation of age and consequently of growth rates, we recommend analysing acetate peels of cross-sections to support the distinction between annual lines and disturbance lines.

  17. Age Differences in Personality Structure: A Cluster Analytic Approach

    ERIC Educational Resources Information Center

    Costa, Paul T., Jr.; McCrae, Robert R.

    1976-01-01

    Presented at the 81st APA Convention, Montreal, 1973, this study showed how a cluster analytic approach was used to determine age differences in personality measured by the Sixteen Personality Factor Questionnaire (16PF). Subjects were 969 adult male volunteers, 25 to 34, 35 to 54, and 55 to 82. Openness to experience showed age-related…

  18. Effects of Aging Structures and Humidity on Fatigue Properties of Maraging Steel

    NASA Astrophysics Data System (ADS)

    Hayashi, Kousuke; Nagano, Takanori; Moriyama, Michihiko; Wang, Xishu; Kawagoishi, Norio

    Effects of aging structures and humidity on fatigue properties of 350 grade 18% Ni maraging steel were investigated under rotating bending in relative humidity of 25% and 85%. Aging conditions tested were a conventional single aging and a double one which was aged at low temperature after the conventional aging. In each aging, under and peak aged steels were prepared. Tensile strength was increased by the double aging without reduction of the ductility. Proportional relation between fatigue limit and Vickers hardness held until 750HV in low humidity. However fatigue strength was largely decreased by high humidity, especially in the peak aged steel at the single aging. The decrease in fatigue strength by high humidity was mainly caused by the acceleration of a crack initiation due to the anodic dissolution. The acceleration of a crack initiation was larger in the steel peak aged at the single aging with larger precipitated particles.

  19. Fragmented Romanian Sociology: Growth and Structure of the Collaboration Network

    PubMed Central

    Hâncean, Marian-Gabriel; Perc, Matjaž; Vlăsceanu, Lazăr

    2014-01-01

    Structural patterns in collaboration networks are essential for understanding how new ideas, research practices, innovation or cooperation circulate and develop within academic communities and between and within university departments. In our research, we explore and investigate the structure of the collaboration network formed by the academics working full-time within all the 17 sociology departments across Romania. We show that the collaboration network is sparse and fragmented, and that it constitutes an environment that does not promote the circulation of new ideas and innovation within the field. Although recent years have witnessed an increase in the productivity of Romanian sociologists, there is still ample room for improvement in terms of the interaction infrastructure that ought to link individuals together so that they could maximize their potentials. We also fail to discern evidence in favor of the Matthew effect governing the growth of the network, which suggests scientific success and productivity are not rewarded. Instead, the structural properties of the collaboration network are partly those of a core-periphery network, where the spread of innovation and change can be explained by structural equivalence rather than by interpersonal influence models. We also provide support for the idea that, within the observed network, collaboration is the product of homophily rather than prestige effects. Further research on the subject based on data from other countries in the region is needed to place our results in a comparative framework, in particular to discern whether the behavior of the Romanian sociologist community is unique or rather common. PMID:25409180

  20. Chronic Blockade of the Androgen Receptor Abolishes Age-Dependent Increases in Blood Pressure in Female Growth-Restricted Rats.

    PubMed

    Dasinger, John Henry; Intapad, Suttira; Rudsenske, Benjamin R; Davis, Gwendolyn K; Newsome, Ashley D; Alexander, Barbara T

    2016-06-01

    Intrauterine growth restriction induced via placental insufficiency programs a significant increase in blood pressure at 12 months of age in female growth-restricted rats that is associated with early cessation of estrous cyclicity, indicative of premature reproductive senescence. In addition, female growth-restricted rats at 12 months of age exhibit a significant increase in circulating testosterone with no change in circulating estradiol. Testosterone is positively associated with blood pressure after menopause in women. Thus, we tested the hypothesis that androgen receptor blockade would abolish the significant increase in blood pressure that develops with age in female growth-restricted rats. Mean arterial pressure was measured in animals pretreated with and without the androgen receptor antagonist, flutamide (8 mg/kg/day, SC for 2 weeks). Flutamide abolished the significant increase in blood pressure in growth-restricted rats relative to control at 12 months of age. To examine the mechanism(s) by which androgens contribute to increased blood pressure in growth-restricted rats, blood pressure was assessed in rats untreated or treated with enalapril (250 mg/L for 2 weeks). Enalapril eliminated the increase in blood pressure in growth-restricted relative to vehicle- and flutamide-treated controls. Furthermore, the increase in medullary angiotensin type 1 receptor mRNA expression was abolished in flutamide-treated growth-restricted relative to untreated counterparts and controls; cortical angiotensin-converting enzyme mRNA expression was reduced in flutamide-treated growth-restricted versus untreated counterparts. Thus, these data indicate that androgens, via activation of the renin-angiotensin system, are important mediators of increased blood pressure that develops by 12 months of age in female growth-restricted rats. PMID:27113045

  1. [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. PMID:26852155

  2. Growth of river delta networks: Thresholds, periodicity, aging and self similarity (Invited)

    NASA Astrophysics Data System (ADS)

    Jerolmack, D. J.; Reitz, M. D.

    2010-12-01

    The surfaces of river deltas and alluvial fans (collectively fans) are often dissected by a small number of channels radiating from the fan apex. These dispersive, depositional systems do not exhibit the fractal scaling typical of erosional drainage networks. On long timescales, fan channels migrate via avulsion - the process of channel bed deposition and abandonment. What governs the selection of new flow paths, or the ultimate number of active channels, is poorly understood. Here we present results of an experimental fan that allow us to examine the growth of a depositional channel network. Flow over the fan collapses into a single channel whose dimensions adjust to threshold transport conditions for the imposed sediment load. This channelization causes localized shoreline growth, which diminishes transport capacity of the channel until the slope drops below the threshold value. This leads to deposition within the channel and widespread flooding; avulsion is completed when a new channel path is selected. This cycle is remarkably periodic, and dynamics suggest that fan slope oscillates between two thresholds - entrainment and distrainment - analogous to static and dynamic angles of repose in grain flows. Selection of a new flow path is inherently stochastic, but previously abandoned channels act as significant attractors for the flow. In the early stages of fan growth, new channels are likely to be created. Once a critical density of flow paths has been established, however, the flow oscillates among the same 3-5 channels indefinitely. These dynamics are similar to the aging phenomenon observed in the growth of fractures in brittle materials under stress. We demonstrate that a directed random walk model with memory quantitatively reproduces these dynamics and limiting behavior, and is consistent with natural fans. Because our experimental fan is built by the recurring avulsion sequence, its shoreline shape is a series of lobes that indicate persistent upstream

  3. Structure, Growth Process, and Growth Mechanism of Perovskite in High-Titanium-Bearing Blast Furnace Slag

    NASA Astrophysics Data System (ADS)

    Liu, Lu; Hu, Meilong; Xu, Yuzhou; Bai, Chenguang; Gan, Yunhua

    2015-08-01

    The isothermal crystallization of perovskite in TiO2-CaO-SiO2-Al2O3-MgO high-titanium-bearing blast furnace slag was observed in situ at 1698 K (1425 °C) using a confocal scanning laser microscope. The dendrite structure of perovskite (CaTiO3) thus obtained showed vividly the primary dendrite trunks and secondary dendrite arms. Furthermore, the dendritic growth of perovskite in liquid slag was clearly observed on line. The results showed that the dendrite arrays in which the primary dendrite trunks observed on slag surface were parallel with each other grew toward the same direction. The secondary dendrite arms grew in the perpendicular direction with the primary trucks and stopped growing when they encounter. The perovskite dendrites showed a linear growth at two stages. The dendrites grew faster at early stage at about 5 to 7 μm/s and grew with a lower growth rate at about 1 to 2 μm/s in later stage. Finally, the growth mechanism of perovskite in melt was analyzed with the solidification theory. Based on the theoretical calculation of equilibrium phases in slag, the initial slag could be considered as a binary component system. One component was perovskite and the other component was the sum of all the other species that did not attend the crystallization of perovskite (included SiO2, Al2O3, and MgO, as well as CaO and TiO2 that were not involved in the solid formation). The formation of perovskite required the diffusion of CaO and TiO2 to the solid/liquid interface and the rejection of the other species from the interface. The solid/liquid equilibrium schematic diagram was made based on the calculation.

  4. Vertebral microanatomy in squamates: structure, growth and ecological correlates

    PubMed Central

    Houssaye, Alexandra; Mazurier, Arnaud; Herrel, Anthony; Volpato, Virginie; Tafforeau, Paul; Boistel, Renaud; de Buffrénil, Vivian

    2010-01-01

    The histological study of vertebrae in extant squamates shows that the internal vertebral structure in this group differs from that of other tetrapods. Squamate vertebrae are lightly built and basically composed of two roughly concentric osseous tubes – one surrounding the neural canal and the other constituting the peripheral cortex of the vertebra – connected by few thin trabeculae. This structure, which characteristically evokes that of a tubular bone, results from a peculiar remodelling process characterised by an imbalance between local bone resorption and redeposition; in both periosteal and endosteo-endochondral territories, bone is extensively resorbed but not reconstructed in the same proportion by secondary deposits. This process is particularly intense in the deep region of the centrum, where originally compact cortices are made cancellous, and where the endochondral spongiosa is very loose. This remodelling process starts at an early stage of development and remains active throughout subsequent growth. The growth of squamate centra is also strongly asymmetrical, with the posterior (condylar) part growing much faster than the anterior (cotylar) part. Preliminary analyses testing for associations between vertebral structure and habitat use suggest that vertebrae of fossorial taxa are denser than those of terrestrial taxa, those in aquatic taxa being of intermediate density. However, phylogenetically informed analyses do not corroborate these findings, thus suggesting a strong phylogenetic signal in the data. As our analyses demonstrate that vertebrae in snakes are generally denser than those of lizards sensu stricto, this may drive the presence of a phylogenetic signal in the data. More comprehensive sampling of fossorial and aquatic lizards is clearly needed to more rigorously evaluate these patterns. PMID:21039477

  5. Structure and Correlates of Cognitive Aging in a Narrow Age Cohort

    PubMed Central

    2014-01-01

    Aging-related changes occur for multiple domains of cognitive functioning. An accumulating body of research indicates that, rather than representing statistically independent phenomena, aging-related cognitive changes are moderately to strongly correlated across domains. However, previous studies have typically been conducted in age-heterogeneous samples over longitudinal time lags of 6 or more years, and have failed to consider whether results are robust to a comprehensive set of controls. Capitalizing on 3-year longitudinal data from the Lothian Birth Cohort of 1936, we took a longitudinal narrow age cohort approach to examine cross-domain cognitive change interrelations from ages 70 to 73 years. We fit multivariate latent difference score models to factors representing visuospatial ability, processing speed, memory, and crystallized ability. Changes were moderately interrelated, with a general factor of change accounting for 47% of the variance in changes across domains. Change interrelations persisted at close to full strength after controlling for a comprehensive set of demographic, physical, and medical factors including educational attainment, childhood intelligence, physical function, APOE genotype, smoking status, diagnosis of hypertension, diagnosis of cardiovascular disease, and diagnosis of diabetes. Thus, the positive manifold of aging-related cognitive changes is highly robust in that it can be detected in a narrow age cohort followed over a relatively brief longitudinal period, and persists even after controlling for many potential confounders. PMID:24955992

  6. Growth rates and ages of deep-sea corals impacted by the Deepwater Horizon oil spill

    USGS Publications Warehouse

    Prouty, Nancy G.; Fisher, Charles R.; Demopoulos, Amanda W. J.; Druffel, Ellen R. M.

    2016-01-01

    The impact of the April 2010 Deepwater Horizon (DWH) spill on deep-sea coral communities in the Gulf of Mexico (GoM) is still under investigation, as is the potential for these communities to recover. Impacts from the spill include observation of corals covered with flocculent material, with bare skeleton, excessive mucous production, sloughing tissue, and subsequent colonization of damaged areas by hydrozoans. Information on growth rates and life spans of deep-sea corals is important for understanding the vulnerability of these ecosystems to both natural and anthropogenic perturbations, as well as the likely duration of any observed adverse impacts. We report radiocarbon ages and radial and linear growth rates based on octocorals (Paramuricea spp. and Chrysogorgia sp.) collected in 2010 and 2011 from areas of the DWH impact. The oldest coral radiocarbon ages were measured on specimens collected 11 km to the SW of the oil spill from the Mississippi Canyon (MC) 344 site: 599 and 55 cal yr BP, suggesting continuous life spans of over 600 years for Paramuricea biscaya, the dominant coral species in the region. Calculated radial growth rates, between 0.34 μm yr−1 and 14.20 μm yr−1, are consistent with previously reported proteinaceous corals from the GoM. Anomalously low radiocarbon (Δ14C) values for soft tissue from some corals indicate that these corals were feeding on particulate organic carbon derived from an admixture of modern surface carbon and a low 14C carbon source. Results from this work indicate fossil carbon could contribute 5–10% to the coral soft tissue Δ14C signal within the area of the spill impact. The influence of a low 14C carbon source (e.g., petro-carbon) on the particulate organic carbon pool was observed at all sites within 30 km of the spill site, with the exception of MC118, which may have been outside of the dominant northeast-southwest zone of impact. The quantitatively assessed extreme longevity and slow growth rates documented

  7. Age and growth of the lake whitefish, Coregonus clupeaformis (Mitchill), in Lake Erie

    USGS Publications Warehouse

    Van Oosten, John; Hile, Ralph

    1949-01-01

    Although the whitefish has by no means ranked first from the standpoint of production, it has always been an important commercial species in Lake Erie. Trends in the output of whitefish have differed in the United States and Canadian waters of the lake. The 1893–1946 average annual yield of 1,201,000 pounds in the United States was only 38.3 percent of the 1879–1890 mean of 3,133,000 pounds, whereas in Canada the more recent (1907–1946) average annual take of 1,397,000 pounds has been 5.48 times the 1871–1906 mean of 255,000 pounds. The United States fishery was centered in the western part of Lake Erie (61.5 percent of the production in Michigan and Ohio) before 1921 and in the eastern part (62.6 percent in Pennsylvania and New York) in 1921–1946. The eastern part of Lake Erie (east of Port Burwell) dominated the Canadian production in 1900–1909 (65.4 percent) and in 1922–1946 (57.2 percent) but the western end was the more productive in 1871–1899 (79.8 percent) and 1910–1921 (69.7 percent). Ages were determined and individual growth histories calculated from the examination and measurement of the scales of 3,399 Lake Erie whitefish captured off four ports (Sandusky, Lorain, and Conneaut, Ohio, and Erie, Pennsylvania) over the period, 1927–1930. The number of specimens used for the investigation of other phases of the life history varied according to the amount of data available or required. Age-group III was typically (but not invariably) dominant in random samples from gear employed for the commercial production of whitefish (trap nets, pound nets, and large-mesh gill nets). The same age group also dominated most samples of the marketable catch (that is, whitefish that equalled or exceeded the minimum legal weight of 1 3/4 pounds) taken in late summer, autumn, and early winter. Age-group IV, however, was strongest among marketable fish from trap nets in early July although the III group was dominant in the random samples from the same nets

  8. FASTRAN II - FATIGUE CRACK GROWTH STRUCTURAL ANALYSIS (UNIX VERSION)

    NASA Technical Reports Server (NTRS)

    Newman, J. C.

    1994-01-01

    Predictions of fatigue crack growth behavior can be made with the Fatigue Crack Growth Structural Analysis (FASTRAN II) computer program. As cyclic loads are applied to a selected crack configuration with an initial crack size, FASTRAN II predicts crack growth as a function of cyclic load history until either a desired crack size is reached or failure occurs. FASTRAN II is based on plasticity-induced crack-closure behavior of cracks in metallic materials and accounts for load-interaction effects, such as retardation and acceleration, under variable-amplitude loading. The closure model is based on the Dugdale model with modifications to allow plastically deformed material to be left along the crack surfaces as the crack grows. Plane stress and plane strain conditions, as well as conditions between these two, can be simulated in FASTRAN II by using a constraint factor on tensile yielding at the crack front to approximately account for three-dimensional stress states. FASTRAN II contains seventeen predefined crack configurations (standard laboratory fatigue crack growth rate specimens and many common crack configurations found in structures); and the user can define one additional crack configuration. The baseline crack growth rate properties (effective stress-intensity factor against crack growth rate) may be given in either equation or tabular form. For three-dimensional crack configurations, such as surface cracks or corner cracks at holes or notches, the fatigue crack growth rate properties may be different in the crack depth and crack length directions. Final failure of the cracked structure can be modelled with fracture toughness properties using either linear-elastic fracture mechanics (brittle materials), a two-parameter fracture criterion (brittle to ductile materials), or plastic collapse (extremely ductile materials). The crack configurations in FASTRAN II can be subjected to either constant-amplitude, variable-amplitude or spectrum loading. The applied

  9. FASTRAN II - FATIGUE CRACK GROWTH STRUCTURAL ANALYSIS (IBM PC VERSION)

    NASA Technical Reports Server (NTRS)

    Newman, J. C.

    1994-01-01

    Predictions of fatigue crack growth behavior can be made with the Fatigue Crack Growth Structural Analysis (FASTRAN II) computer program. As cyclic loads are applied to a selected crack configuration with an initial crack size, FASTRAN II predicts crack growth as a function of cyclic load history until either a desired crack size is reached or failure occurs. FASTRAN II is based on plasticity-induced crack-closure behavior of cracks in metallic materials and accounts for load-interaction effects, such as retardation and acceleration, under variable-amplitude loading. The closure model is based on the Dugdale model with modifications to allow plastically deformed material to be left along the crack surfaces as the crack grows. Plane stress and plane strain conditions, as well as conditions between these two, can be simulated in FASTRAN II by using a constraint factor on tensile yielding at the crack front to approximately account for three-dimensional stress states. FASTRAN II contains seventeen predefined crack configurations (standard laboratory fatigue crack growth rate specimens and many common crack configurations found in structures); and the user can define one additional crack configuration. The baseline crack growth rate properties (effective stress-intensity factor against crack growth rate) may be given in either equation or tabular form. For three-dimensional crack configurations, such as surface cracks or corner cracks at holes or notches, the fatigue crack growth rate properties may be different in the crack depth and crack length directions. Final failure of the cracked structure can be modelled with fracture toughness properties using either linear-elastic fracture mechanics (brittle materials), a two-parameter fracture criterion (brittle to ductile materials), or plastic collapse (extremely ductile materials). The crack configurations in FASTRAN II can be subjected to either constant-amplitude, variable-amplitude or spectrum loading. The applied

  10. Aging Optimization of Aluminum-Lithium Alloy C458 for Application to Cryotank Structures

    NASA Technical Reports Server (NTRS)

    Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Rioja, R.

    2003-01-01

    Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 (Al-1.0 Li-4.0 Cu-0.4 Mg-0.4 Ag-0.12 Zr) for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. These newer alloys generally have lithium content less than 2 wt. % and their composition and processing have been carefully tailored to increase the toughness and reduce the mechanical property anisotropy of the earlier generation alloys such 2090 and 8090. Alloy processing, particularly the aging treatment, has a significant influence on the strength-toughness combinations and their dependence on service environments for aluminum-lithium alloys. Work at NASA Marshall Space Flight Center on alloy 2195 has shown that the cryogenic toughness can be improved by employing a two-step aging process. This is accomplished by aging at a lower temperature in the first step to suppress nucleation of the strengthening precipitate at sub-grain boundaries while promoting nucleation in the interior of the grains. Second step aging at the normal aging temperature results in precipitate growth to the optimum size. A design of experiments aging study was conducted for plate. To achieve the T8 temper, Alloy C458 (Al-1.8 Li-2.7 Cu-0.3 Mg-0.08 Zr-0.3 Mn-0.6 Zn) is typically aged at 300F for 24hours. In this study, a two-step aging treatment was developed through a comprehensive 2(exp 4) full factorial design of experiments study and the typical one-step aging used as a reference. Based on the higher lithium content of C458 compared with 2195, the first step aging temperature was varied between 175F and 250F. The second step aging temperatures was

  11. 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

  12. Age, growth, and food of northern pike in eastern Lake Ontario

    USGS Publications Warehouse

    Wolfert, David R.; Miller, Terence J.

    1978-01-01

    Northern pike (Esox lucius) from eastern Lake Ontario were sampled with gill nets and trap nets in 1972-1973. Fish of age-groups IV, V, and VI were predominant in the catch. Although males were slightly longer after the 1st yr of life, females gained a 25-mm advantage in the 2nd yr and a 30-mm advantage in the 3rd yr. In later years, the increments of growth of males and females were similar. All males were mature after 2 yr and females after 3 yr. The stomachs of northern pike contained only fish; the alewife (Alosa pseudoharengus) was the principal forage species consumed. Electivity indexes for alewives, white perch (Morone americana), and yellow perch (Perca flavescens), the three most common species in the diet, indicated a positive selection for alewives that increased from June to October during a period when the relative abundance of alewives steadily decreased.

  13. Growth Mechanism of a Unique Hierarchical Vaterite Structure

    NASA Astrophysics Data System (ADS)

    Ma, Guobin; Xu, Yifei; Wang, Mu

    2013-03-01

    Calcium carbonate is one of the most significant minerals in nature as well as in biogenic sources. Calcium carbonate occurs naturally in three crystalline polymorphs, i.e., calcite, aragonite, and vaterite. Although it has been attracted much research attention to understanding of the formation mechanisms of the material, the properties of the vaterite polymorph is not well known. Here we report synthesis and formation mechanism of a unique hierarchical structure of vaterite. The material is grown by a controlled diffusion method. The structure possesses a core and an outer part. The core is convex lens-like and is formed by vaterite nanocrystals that have small misorientations. The outer part is separated into six garlic clove-like segments. Each segment possesses piles of plate-like vaterite crystals, and the orientations of the plates continuously change from pile to pile. Based on real-time experimental results and the structural analysis, a growth mechanism is presented. Work supported by NSFC (Grant No. 51172104) and MOST of China (Grant No. 2101CB630705)

  14. Age of Onset of Schizophrenia: Perspectives From Structural Neuroimaging Studies

    PubMed Central

    Gogtay, Nitin; Vyas, Nora S.; Testa, Renee; Wood, Stephen J.; Pantelis, Christos

    2011-01-01

    Many of the major neuropsychiatric illnesses, including schizophrenia, have a typical age of onset in late adolescence. Late adolescence may reflect a critical period in brain development making it particularly vulnerable for the onset of psychopathology. Neuroimaging studies that focus on this age range may provide unique insights into the onset and course of psychosis. In this review, we examine the evidence from 2 unique longitudinal cohorts that span the ages from early childhood through young adulthood; a study of childhood-onset schizophrenia where patients and siblings are followed from ages 6 through to their early twenties, and an ultra-high risk study where subjects (mean age of 19 years) are studied before and after the onset of psychosis. From the available evidence, we make an argument that subtle, regionally specific, and genetically influenced alterations during developmental age windows influence the course of psychosis and the resultant brain phenotype. The importance of examining trajectories of development and the need for future combined approaches, using multimodal imaging together with molecular studies is discussed. PMID:21505117

  15. Age of onset of schizophrenia: perspectives from structural neuroimaging studies.

    PubMed

    Gogtay, Nitin; Vyas, Nora S; Testa, Renee; Wood, Stephen J; Pantelis, Christos

    2011-05-01

    Many of the major neuropsychiatric illnesses, including schizophrenia, have a typical age of onset in late adolescence. Late adolescence may reflect a critical period in brain development making it particularly vulnerable for the onset of psychopathology. Neuroimaging studies that focus on this age range may provide unique insights into the onset and course of psychosis. In this review, we examine the evidence from 2 unique longitudinal cohorts that span the ages from early childhood through young adulthood; a study of childhood-onset schizophrenia where patients and siblings are followed from ages 6 through to their early twenties, and an ultra-high risk study where subjects (mean age of 19 years) are studied before and after the onset of psychosis. From the available evidence, we make an argument that subtle, regionally specific, and genetically influenced alterations during developmental age windows influence the course of psychosis and the resultant brain phenotype. The importance of examining trajectories of development and the need for future combined approaches, using multimodal imaging together with molecular studies is discussed. PMID:21505117

  16. Birth Weight, Birth Length, and Gestational Age as Indicators of Favorable Fetal Growth Conditions in a US Sample

    PubMed Central

    Bollen, Kenneth A.

    2016-01-01

    The “fetal origins” hypothesis suggests that fetal conditions not only affect birth characteristics such as birth weight and gestational age, but also have lifelong health implications. Despite widespread interest in this hypothesis, few methodological advances have been proposed to improve the measurement and modeling of fetal conditions. A Statistics in Medicine paper by Bollen, Noble, and Adair examined favorable fetal growth conditions (FFGC) as a latent variable. Their study of Filipino children from Cebu provided evidence consistent with treating FFGC as a latent variable that largely mediates the effects of mother’s characteristics on birth weight, birth length, and gestational age. This innovative method may have widespread utility, but only if the model applies equally well across diverse settings. Our study assesses whether the FFGC model of Cebu replicates and generalizes to a very different population of children from North Carolina (N = 705) and Pennsylvania (N = 494). Using a series of structural equation models, we find that key features of the Cebu analysis replicate and generalize while we also highlight differences between these studies. Our results support treating fetal conditions as a latent variable when researchers test the fetal origins hypothesis. In addition to contributing to the substantive literature on measuring fetal conditions, we also discuss the meaning and challenges involved in replicating prior research. PMID:27097023

  17. The Polycomb Group Protein Pcgf1 Is Dispensable in Zebrafish but Involved in Early Growth and Aging.

    PubMed

    Dupret, Barbara; Völkel, Pamela; Le Bourhis, Xuefen; Angrand, Pierre-Olivier

    2016-01-01

    Polycomb Repressive Complex (PRC) 1 regulates the control of gene expression programs via chromatin structure reorganization. Through mutual exclusion, different PCGF members generate a variety of PRC1 complexes with potentially distinct cellular functions. In this context, the molecular function of each of the PCGF family members remains elusive. The study of PCGF family member expression in zebrafish development and during caudal fin regeneration reveals that the zebrafish pcgf genes are subjected to different regulations and that all PRC1 complexes in terms of Pcgf subunit composition are not always present in the same tissues. To unveil the function of Pcgf1 in zebrafish, a mutant line was generated using the TALEN technology. Mutant pcgf1-/- fish are viable and fertile, but the growth rate at early developmental stages is reduced in absence of pcgf1 gene function and a significant number of pcgf1-/- fish show signs of premature aging. This first vertebrate model lacking Pcgf1 function shows that this Polycomb Group protein is involved in cell proliferation during early embryogenesis and establishes a link between epigenetics and aging. PMID:27442247

  18. The Polycomb Group Protein Pcgf1 Is Dispensable in Zebrafish but Involved in Early Growth and Aging

    PubMed Central

    Le Bourhis, Xuefen; Angrand, Pierre-Olivier

    2016-01-01

    Polycomb Repressive Complex (PRC) 1 regulates the control of gene expression programs via chromatin structure reorganization. Through mutual exclusion, different PCGF members generate a variety of PRC1 complexes with potentially distinct cellular functions. In this context, the molecular function of each of the PCGF family members remains elusive. The study of PCGF family member expression in zebrafish development and during caudal fin regeneration reveals that the zebrafish pcgf genes are subjected to different regulations and that all PRC1 complexes in terms of Pcgf subunit composition are not always present in the same tissues. To unveil the function of Pcgf1 in zebrafish, a mutant line was generated using the TALEN technology. Mutant pcgf1-/- fish are viable and fertile, but the growth rate at early developmental stages is reduced in absence of pcgf1 gene function and a significant number of pcgf1-/- fish show signs of premature aging. This first vertebrate model lacking Pcgf1 function shows that this Polycomb Group protein is involved in cell proliferation during early embryogenesis and establishes a link between epigenetics and aging. PMID:27442247

  19. Validating Annual Growth Bands of Deep-Sea Black Corals and Calculating Ocean Reservoir Ages in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Roark, E. B.; Mohon, M. L.; Prouty, N.; Guillemette, R. N.; Fallon, S.; Ross, S. W.

    2015-12-01

    Deep-sea black corals (Leiopathes sp.) are long-lived (up to 4,000 yrs old), and grow in a tree-like fashion depositing growth rings in their skeleton. Scanning electron microscopy at 900x magnification was used to image thin sections and identify peaks in iodine intensity using energy dispersive x-ray spectroscopy in three specimens from the Gulf of Mexico. Age determination by counting visual growth bands and iodine peaks were compared to both radiocarbon and U/Th-derived ages. The first specimen (GOM-JSL04-4734-BC1) has an iodine peak count age of 695 ±70, and growth band age of 785 ± 80 which compare quite well to the radiocarbon age of 670 ±40 years and a U/Th age of 780 ±16 years. There was similar agreement between the radiocarbon ages (1399 ±30 and 670 ±35 years) and the iodine peak count ages (1240 ±125 and 715±70 years) for the remaining two specimens with growth rates ranging from 11 ±3 to 16 ±2 µm yr-1 for all 3 specimens. Using the independent (iodine derived) age models in conjunction with the radiocarbon data, a high resolution ocean reservoir age record was developed for the last 600 years. Reservoir ages varied from 120 to 550 14C years on decadal to centennial time scales. The modern reservoir age in the GOM is 235 ±11 14C years. The preferred explanation for the variability found in these reservoir ages is related to changes in the strength of the Yucatan Current. This novel approach combines the identification of growth bands captured in high-resolution SEM in combination with synchronous peaks in skeleton iodine composition and is the first to validate that both can be used as annual chronometers. Using the independent iodine age models in conjunction with the radiocarbon records, ocean reservoir age records can be developed for the last ~500 to 1000 years.

  20. Growth of Cosmic Structure: Probing Dark Energy Beyond Expansion

    SciTech Connect

    Huterer, Dragan; Kirkby, David; Bean, Rachel; Connolly, Andrew; Dawson, Kyle; Dodelson, Scott; Evrard, August; Jain, Bhuvnesh; Jarvis, Michael; Linder, Eric; Mandelbaum, Rachel; May, Morgan; Raccanelli, Alvise; Reid, Beth; Rozo, Eduardo; Schmidt, Fabian; Sehgal, Neelima; Slosar, Anze; Van Engelen, Alex; Wu, Hao-Yi; Zhao, Gongbo

    2014-03-15

    The quantity and quality of cosmic structure observations have greatly accelerated in recent years, and further leaps forward will be facilitated by imminent projects. These will enable us to map the evolution of dark and baryonic matter density fluctuations over cosmic history. The way that these fluctuations vary over space and time is sensitive to several pieces of fundamental physics: the primordial perturbations generated by GUT-scale physics; neutrino masses and interactions; the nature of dark matter and dark energy. We focus on the last of these here: the ways that combining probes of growth with those of the cosmic expansion such as distance-redshift relations will pin down the mechanism driving the acceleration of the Universe.

  1. Growth of Cosmic Structure: Probing Dark Energy Beyond Expansion

    DOE PAGESBeta

    Huterer, Dragan; Kirkby, David; Bean, Rachel; Connolly, Andrew; Dawson, Kyle; Dodelson, Scott; Evrard, August; Jain, Bhuvnesh; Jarvis, Michael; Linder, Eric; et al

    2014-03-15

    The quantity and quality of cosmic structure observations have greatly accelerated in recent years, and further leaps forward will be facilitated by imminent projects. These will enable us to map the evolution of dark and baryonic matter density fluctuations over cosmic history. The way that these fluctuations vary over space and time is sensitive to several pieces of fundamental physics: the primordial perturbations generated by GUT-scale physics; neutrino masses and interactions; the nature of dark matter and dark energy. We focus on the last of these here: the ways that combining probes of growth with those of the cosmic expansionmore » such as distance-redshift relations will pin down the mechanism driving the acceleration of the Universe.« less

  2. Lake Erie Yellow perch age estimation based on three structures: Precision, processing times, and management implications

    USGS Publications Warehouse

    Vandergoot, C.S.; Bur, M.T.; Powell, K.A.

    2008-01-01

    Yellow perch Perca flavescens support economically important recreational and commercial fisheries in Lake Erie and are intensively managed. Age estimation represents an integral component in the management of Lake Erie yellow perch stocks, as age-structured population models are used to set safe harvest levels on an annual basis. We compared the precision associated with yellow perch (N = 251) age estimates from scales, sagittal otoliths, and anal spine sections and evaluated the time required to process and estimate age from each structure. Three readers of varying experience estimated ages. The precision (mean coefficient of variation) of estimates among readers was 1% for sagittal otoliths, 5-6% for anal spines, and 11-13% for scales. Agreement rates among readers were 94-95% for otoliths, 71-76% for anal spines, and 45-50% for scales. Systematic age estimation differences were evident among scale and anal spine readers; less-experienced readers tended to underestimate ages of yellow perch older than age 4 relative to estimates made by an experienced reader. Mean scale age tended to underestimate ages of age-6 and older fish relative to otolith ages estimated by an experienced reader. Total annual mortality estimates based on scale ages were 20% higher than those based on otolith ages; mortality estimates based on anal spine ages were 4% higher than those based on otolith ages. Otoliths required more removal and preparation time than scales and anal spines, but age estimation time was substantially lower for otoliths than for the other two structures. We suggest the use of otoliths or anal spines for age estimation in yellow perch (regardless of length) from Lake Erie and other systems where precise age estimates are necessary, because age estimation errors resulting from the use of scales could generate incorrect management decisions. ?? Copyright by the American Fisheries Society 2008.

  3. Demography of deep-dwelling red coral populations: Age and reproductive structure of a highly valued marine species

    NASA Astrophysics Data System (ADS)

    Priori, Cristina; Mastascusa, Vincenza; Erra, Fabrizio; Angiolillo, Michela; Canese, Simonpietro; Santangelo, Giovanni

    2013-02-01

    The valuable Mediterranean red coral Corallium rubrum (Octocorallia Gorgonacea) has been harvested for more than 2 thousand years. Although our knowledge on the demographic features of red coral populations living between 10 and 50 m depth has increased considerably in recent years, the main life-history traits of deeper populations (the main target of current harvesting) are still largely unknown. To increase the demographic knowledge of the latter populations, sampling was carried out during early Summer 2010 in the North-Western Mediterranean (Tyrrhenian Sea - Italy), between 50 and 130 m depth. This paper quantifies the main demographic descriptors of this coral population in terms of size/age and sexual structure. Colony age was estimated by counting annual growth rings on thin sections of 69 colonies. A 2-way ANOVA showed no significant difference between the age estimated by three independent observers. The average annual colony growth rate (basal diameter), showing some decrease with colony age increase, was 0.26 mm/yr. The relationship between age and basal diameter derived from a subsample of colonies was then applied to assess the age of a larger sample of the population and showed 38% of the sampled colonies reached the commercial size (≥7 mm of basal diameter), corresponding to about 30 years in this population and a maximum life span of 93 years; about half of them (51.1%) were in the 21-25 and 26-30 age classes. The analysis of the sexual features revealed a balanced sex ratio, a colony fertility of 90.3% and an average fecundity of 0.83 oocytes or planulae per polyp. The knowledge of these life-history descriptors is needed for our understanding of deep dwelling red coral population dynamics and for matching of harvesting to population growth rate.

  4. Motor Control and Aging: Links to Age-Related Brain Structural, Functional, and Biochemical Effects

    PubMed Central

    Seidler, Rachael D.; Bernard, Jessica A.; Burutolu, Taritonye B.; Fling, Brett W.; Gordon, Mark T.; Gwin, Joseph T.; Kwak, Youngbin; Lipps, David B.

    2009-01-01

    Although connections between cognitive deficits and age-associated brain differences have been elucidated, relationships with motor performance are less well understood. Here, we broadly review age-related brain differences and motor deficits in older adults in addition to cognition-action theories. Age-related atrophy of the motor cortical regions and corpus callosum may precipitate or coincide with motor declines such as balance and gait deficits, coordination deficits, and movement slowing. Correspondingly, degeneration of neurotransmitter systems—primarily the dopaminergic system—may contribute to age-related gross and fine motor declines, as well as to higher cognitive deficits. In general, older adults exhibit involvement of more widespread brain regions for motor control than young adults, particularly the prefrontal cortex and basal ganglia networks. Unfortunately these same regions are the most vulnerable to age-related effects, resulting in an imbalance of “supply and demand”. Existing exercise, pharmaceutical, and motor training interventions may ameliorate motor deficits in older adults. PMID:19850077

  5. Migrational changes of mesenchymal stem cells in response to cytokines, growth factors, hypoxia, and aging.

    PubMed

    Naaldijk, Yahaira; Johnson, Adiv A; Ishak, Stefan; Meisel, Hans Jörg; Hohaus, Christian; Stolzing, Alexandra

    2015-10-15

    Mesenchymal stem cells (MSCs) are non-immunogenic, multipotent cells with at least trilineage differentiation potential. They promote wound healing, improve regeneration of injured tissue, and mediate numerous other health effects. MSCs migrate to sites of injury and stimulate repair either through direct differentiation or indirectly through the stimulation of endogenous repair mechanisms. Using the in vitro scratch assay, we show that the inflammatory cytokines, chemokines, and growth factors TNF-α, SDF-1, PDGF, and bFGF enhance migration of rat MSCs under normoxic conditions, while TNF-α, IFN-γ, PDGF, and bFGF promote MSC migration under hypoxic conditions. This indicates that the oxygen concentration affects how MSCs will migrate in response to specific factors and, consistent with this, differential expression of cytokines was observed under hypoxic versus normoxic conditions. Using the transwell migration assay, we find that TNF-α, IFN-γ, bFGF, IGF-1, PDGF, and SDF-1 significantly increase transmigration of rat MSCs compared to unstimulated medium. MSCs derived from aged rats exhibited comparable migration to MSCs derived from young rats under hypoxic and normoxic conditions, even after application with specific factors. Similarly, migration in MSCs from aged, human donors did not statistically differ compared to migration in MSCs derived from human umbilical cord tissue or younger donors. PMID:26335540

  6. Antivascular Endothelial Growth Factor Agents for Neovascular Age-Related Macular Degeneration

    PubMed Central

    Zampros, Ilias; Praidou, Anna; Brazitikos, Periklis; Ekonomidis, Panagiotis; Androudi, Sofia

    2012-01-01

    Age-related macular degeneration (AMD) is the leading cause of severe visual loss and blindness over the age of 50 in developed countries. Vascular endothelial growth factor (VEGF) is considered as a critical molecule in the pathogenesis of choroidal neovascularization (CNV), which characterizes the neovascular AMD. Anti-VEGF agents are considered the most promising way of effectively inhibition of the neovascular AMD process. VEGF is a heparin-binding glycoprotein with potent angiogenic, mitogenic and vascular permeability-enhancing activities specific for endothelial cells. Two anti-VEGF agents have been approved by the US Food and Drug Administration (FDA) for the treatment of neovascular AMD. Pegaptanib sodium, which is an aptamer and ranibizumab, which is a monoclonal antibody fragment. Another humanized monoclonal antibody is currently off-label used, bevacizumab. This paper aims to discuss in details the effectiveness, the efficacy and safety of these three anti-VEGF agents. New anti-VEGF compounds which are recently investigated for their clinical usage (VEGF-trap, small interfering RNA) are also discussed for their promising outcomes. PMID:22174998

  7. Significant roles of anti-aging protein klotho and fibroblast growth factor23 in cardiovascular disease

    PubMed Central

    Ding, Hong-Ying; Ma, Hou-Xun

    2015-01-01

    The klotho gene has been identified as an aging suppressor that encodes a protein involved in cardiovascular disease (CVD). The inactivation of the klotho gene causes serious systemic disorders resembling human aging, such as atherosclerosis, diffuse vascular calcification and shortened life span. Klotho has been demonstrated to ameliorate vascular endothelial dysfunction and delay vascular calcification. Furthermore, klotho gene polymorphisms in the human are associated with various cardiovascular events. Recent experiments show that klotho may reduce transient receptor potential canonical6 (TRPC6) channels, resulting in protecting the heart from hypertrophy and systolic dysfunction. Fibroblast growth factor23 (FGF23) is a bone-derived hormone that plays an important role in the regulation of phosphate and vitamin D metabolism. FGF23 accelerates urinary phosphate excretion and suppresses 1,25-dihydroxy vitaminD3 (1,25(OH)2D3) synthesis in the presence of FGF receptor1 (FGFR1) and its co-receptor klotho, principally in the kidney. The hormonal affects of circulating klotho protein and FGF23 on vascular and heart have contributed to an understanding of their roles in the pathophysiology of arterial stiffness and left ventricular hypertrophy. Klotho and FGF23 appear to play a critical role in the pathogenesis of vascular disease, and may represent a novel potential therapeutic strategy for clinical intervention. PMID:26347327

  8. 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.

  9. A mixed longitudinal anthropometric study of craniofacial growth of Colombian mestizos 6-17 years of age.

    PubMed

    Arboleda, Cleidy; Buschang, Peter H; Camacho, Jesus A; Botero, Paola; Roldan, Samuel

    2011-08-01

    The purpose of this study was to evaluate the craniofacial growth of Colombian mestizos. Four age cohorts, including a total of 458 children and adolescents (262 males and 216 females), were included in this mixed-longitudinal study. The cohorts were first measured at ages 6, 9, 12, and 15 and every year thereafter for 3 years. Eight anthropometric measurements were taken, including three cranial (head perimeter, head width, and head length), two craniofacial (maxillary and mandibular length), and three facial (face height, bizygomatic width, and bigonial width). Multilevel analyses showed that all dimensions increased between 6 and 17 years of age. The cranium grew less than the craniofacial, which in turn grew less than the facial dimensions. In addition, vertical dimensions showed more growth than antero-posterior dimensions, which in turn grew more than transverse dimensions. None of the measurement showed statistically significant growth differences between subjects with normal occlusion and Class I or Class II malocclusions. Males were generally larger than females and showed greater growth rates. Except for facial width, whose yearly velocities decreased regularly with age, an adolescent growth spurt was evident for most of the male measurements. Yearly velocities for females followed a simpler decelerating pattern. The results provide reference data for Colombian mestizos, for whom normative data of other ethnic groups are not applicable. While occlusion had little or no effect, there were gender differences, as well as important growth differences between cranial and facial measurements. PMID:21097992

  10. ZnO Nanoporous Structure Growth, Optical and Structural Characterization by Aqueous Solution Route

    NASA Astrophysics Data System (ADS)

    Kashif, M.; Ali, Syed M. Usman; Foo, K. L.; Hashim, U.; Willander, Magnus

    2011-05-01

    In this study, we have demonstrated the structural and optical characterization of ZnO nanoporous structure grown on gold coated plastic substrate using low temperature aqueous chemical growth (ACG) technique and the annealing temperature was kept at 150° C. ZnO nanoporous structures were fabricated using hydrolysis process by reacting zinc acetate dehydrate with anhydrous ethanol. The crystalline morphology of ZnO nanoporous structures were investigated by using X-ray diffraction (XRD), surface morphology was observed by field emission scanning electron microscope (FESEM). The optical characteristics of ZnO nanoporous structures were investigated at room temperature, PL was observed using UV-Vis Spectrophotometer and the chemical composition is analyzed using Fourier Transform Infra-Red spectrometer (FTIR).

  11. NDE of hidden flaws in aging aircraft structures using obliquely backscattered ultrasonic signals (OBUS)

    NASA Astrophysics Data System (ADS)

    Bar-Cohen, Yoseph; Mal, Ajit K.; Lasser, Marvin E.

    1999-01-01

    Corrosion is a relatively slow material degradation process to which metallic structures of aircraft are subjected during service and it can appear in many forms. Generally, corrosion protection for preventing or inhibiting the formation and growth of corrosion damage on aircraft structures is well-established technology. Unfortunately, despite preventive measures, corrosion does occur and its probability of formation significantly increases as structures age. Corrosion detection and characterization at the initiation stages, while hidden under paint or in concealed areas, still poses a challenge to inspection science and technology. Corrosion damage is costly and it carries the risk of loss of life as well as hardware in case of catastrophic failure. The authors are investigating the application of obliquely backscattered ultrasonic signals (OBUS) as a means of detecting and characterizing corrosion under paint in metallic panels. OBUS were measured using oblique insonification and were used to produce C-scan images of corrosion damage located on both top and bottom faces of test panels through the paint. A combination of OBUS data and a sensor-array real-time imaging (SARTI) system is being developed for field applications. SARTI uses CCD to display ultrasonic data nd the integrated system has the potential to reduce the need for paint stripping prior to inspection. The main features of the combined OBUS and SARTI are described in this paper.

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

    PubMed Central

    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. PMID:25973854

  13. 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

  14. Aortic Aging in ESRD: Structural, Hemodynamic, and Mortality Implications.

    PubMed

    London, Gérard M; Safar, Michel E; Pannier, Bruno

    2016-06-01

    Aging incurs aortic stiffening and dilation, but these changes are less pronounced in peripheral arteries, resulting in stiffness and geometry gradients influencing progression of the forward and reflected pressure waves. Because premature arterial aging is observed in ESRD, we determined the respective roles of stiffness and aortic geometry gradients in 73 controls and 156 patients on hemodialysis. We measured aortic pulse wave velocity (PWV) and brachial PWV to evaluate the stiffness gradient [(brachial PWV/aortic PWV)(0.5)] and ascending aortic and aortic bifurcation diameters to assess aortic taper (ascending aortic diameter/aortic bifurcation diameter). The global reflection coefficient was estimated from characteristic impedance and vascular resistance. Cox proportional hazard models were used to determine mortality risk. The age-associated increase in aortic PWV was higher in patients (P<0.001). In controls, aortic ascending and bifurcation diameters increased with age, with an unchanged aortic taper. In patients on hemodialysis, age did not associate with increased ascending aortic diameter but did associate with increased aortic bifurcation diameter and decreased aortic taper, both of which also associated with abdominal aortic calcifications and smaller global reflection coefficient (P<0.001). In patients, multivariate models revealed all-cause and cardiovascular mortality associated with age, aortic PWV, and aortic bifurcation diameter with high specificity and sensitivity. Using stiffness gradient, aortic taper, or global reflection coefficient in the model produced similar results. Thus, whereas aortic stiffness is a known independent predictor of mortality, these results indicate the importance of also evaluating the aortic geometry in patients on hemodialysis. PMID:26475595

  15. On the dynamics of the age structure, dependency, and consumption

    PubMed Central

    Hock, Heinrich

    2013-01-01

    We examine the effects of population aging due to declining fertility and rising elderly life expectancy on consumption possibilities in the presence of intergenerational transfers. Our analysis is based on a highly tractable continuous-time overlapping generations model in which the population is divided into three groups (youth dependents, workers, and elderly dependents) and lifecourse transitions take place in a probabilistic fashion. We show that the consumption-maximizing response to greater longevity in highly developed countries is an increase in fertility. However, with larger transfer payments, the actual fertility response will likely be the opposite, leading to further population aging. PMID:24353374

  16. Type I collagen aging impairs discoidin domain receptor 2-mediated tumor cell growth suppression.

    PubMed

    Saby, Charles; Buache, Emilie; Brassart-Pasco, Sylvie; El Btaouri, Hassan; Courageot, Marie-Pierre; Van Gulick, Laurence; Garnotel, Roselyne; Jeannesson, Pierre; Morjani, Hamid

    2016-05-01

    Tumor cells are confronted to a type I collagen rich environment which regulates cell proliferation and invasion. Biological aging has been associated with structural changes of type I collagen. Here, we address the effect of collagen aging on cell proliferation in a three-dimensional context (3D).We provide evidence for an inhibitory effect of adult collagen, but not of the old one, on proliferation of human fibrosarcoma HT-1080 cells. This effect involves both the activation of the tyrosine kinase Discoidin Domain Receptor 2 (DDR2) and the tyrosine phosphatase SHP-2. DDR2 and SHP-2 were less activated in old collagen. DDR2 inhibition decreased SHP-2 phosphorylation in adult collagen and increased cell proliferation to a level similar to that observed in old collagen.In the presence of old collagen, a high level of JAK2 and ERK1/2 phosphorylation was observed while expression of the cell cycle negative regulator p21CIP1 was decreased. Inhibition of DDR2 kinase function also led to an increase in ERK1/2 phosphorylation and a decrease in p21CIP1 expression. Similar signaling profile was observed when DDR2 was inhibited in adult collagen. Altogether, these data suggest that biological collagen aging could increase tumor cell proliferation by reducingthe activation of the key matrix sensor DDR2. PMID:27121132

  17. Combined Administration of Human Ghrelin and Human Growth Hormone Attenuates Organ Injury and Improves Survival in Aged Septic Rats

    PubMed Central

    Yang, Weng-Lang; Ma, Gaifeng; Zhou, Mian; Aziz, Monowar; Yen, Hao-Ting; Marvropoulos, Spyros A; Ojamaa, Kaie; Wang, Ping

    2016-01-01

    Sepsis is a major healthcare concern, especially in the elderly population. The use of an animal model closely resembling clinical conditions in this population may provide a better prediction in translating bench studies to the bedside. Ghrelin inhibits sympathetic nerve activity and inflammation in young septic animals; however, aged animals become hyporesponsive to ghrelin. In this study, we evaluated the efficacy of combined human ghrelin and growth hormone (GH) for sepsis treatment in the elderly utilizing a clinically relevant animal model of sepsis. Male Fischer 344 rats 22 to 24 months old were subjected to cecal ligation and puncture (CLP). Human ghrelin plus GH or vehicle (normal saline) was administered subcutaneously at 5 h after CLP. At 20 h after CLP, blood and tissue samples were collected for various analyses. Combined treatment attenuated serum levels of lactate, lactate dehydrogenase, creatinine, blood urea nitrogen, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in aged septic rats. The integrity of the microscopic structure in the lungs, liver and kidneys was well preserved after treatment. Expression of IL-6, TNF-α, macrophage inflammatory protein-2 and keratinocyte-derived chemokine as well as myeloperoxidase activity and caspase-3 activation were significantly reduced in the lungs and liver of treated rats. Moreover, treated rats showed an improvement in cardiovascular function and increased expression of ghrelin receptor and c-fos in the brainstem. Finally, the 10-d survival of aged septic rats was increased from 29% to 64% after combined treatment and was associated with less body weight loss. Our findings warrant the development of combined human ghrelin and GH for sepsis treatment in the geriatric population. PMID:26835699

  18. Structure and growth of tetracene on Ag(111)

    NASA Astrophysics Data System (ADS)

    Soubatch, S.; Kröger, I.; Kumpf, C.; Tautz, F. S.

    2011-11-01

    The structure of the tetracene/Ag(111) interface in the coverage range θ = 0 to 2.4 ML is studied with scanning tunneling microscopy (STM) at 8 K and with low energy electron diffraction (LEED) at T = 300 … 100 K. For θ ≲ 0.01 ML, one-dimensional (1D) diffusion of single molecules along <011¯>-directions is observed even at 8 K. For 0.1 ML < θ < 0.5 ML molecules are homogeneously distributed over the surface forming a disordered phase (static at T = 8 K, dynamic at T = 25 K), indicating a repulsive intermolecular interaction (δ-phase). For θ ≳ 0.5 ML, local ordering in the commensurate γ-phase is observed. Further increase of the coverage yields a compressed monolayer (ML) phase (θ ≡ 1 ML) with point-on-line registry (α-phase). The interaction between molecules has been calculated with the force-field approach to rationalize the molecular packing motifs in the various phases. Under most circumstances molecule-molecule interactions are repulsive, in agreement with experimental findings. A simulation of the adsorption up to θ = 1 ML according to the random sequential adsorption (RSA) algorithm shows that the disorder-to-order transition from the δ- to γ-phase occurs close to random close packing (RCP), θ = 0.5-0.6 ML. Since tetracene molecules are a two-dimensional (2D) representation of Onsager's hard rod model, this suggests that this phase transition is driven both energetically and entropically. For θ ≈ 2.23 ML a metastable bilayer phase with point-on-line coincidence is observed (β-phase). The basic structural unit of this phase is a triplet of molecules that are tilted along the long molecular axis against each other; at least one of these molecules is tilted out of the surface plane. Within the β-phase a superstructure of alternating rotation domains is observed. This superstructure has a period of 7.4 nm. The molecular packing in the β-phase resembles the packing in the bulk crystal structure of tetracene, its formation can

  19. The Frontal Hypothesis of Cognitive Aging: Factor Structure and Age Effects on Four "Frontal Tests" among Healthy Individuals

    ERIC Educational Resources Information Center

    Rodriguez-Aranda, Claudia; Sundet, Kjetil

    2006-01-01

    With 101 healthy aging adult participants, the authors investigated whether executive functions are a unitary concept. The authors established the factor structure of the Wisconsin Card Sorting Test (WCST; E. A. Berg, 1948), the Stroop color and word test (C. J. Golden, 1978), verbal fluency using the Controlled Oral Word Association Test (COWAT;…

  20. What will 1984 be like? Socioeconomic implications of recent twists in age structure.

    PubMed

    Easterlin, R A

    1978-11-01

    Since 1940, under conditions of restricted immigration and high and sustained growth in aggregate demand, shifts in the relative number of younger versus older adults have had a pervasive impact on American life. Before 1960, younger males were in increasingly short supply and their relative economic position substantially improved; after 1960, the opposite was true. Since the early sixties, as the relative condition of young adults has deteriorated, marriage has been increasingly deferred and fertility reduced. The labor force participation of young women has risen at above average rates, and that of older women has risen at below average rates. Changes in the age structure of the working age population have also contributed to a combination of rising unemployment and accelerating inflation. Cohort divorce rates, suicide among young males, crime rates, and political alienation have worsened. The rise in college enrollment rates has been interrupted, and SAT scores have declined. In contrast, in the period 1940-1960, changes in these various magnitudes were typically of a more favorable sort. The United States is now at the start of a new period of growing scarcity of young adults as a result of the birth rate decline that set in after 1960. This implies that the 1980s will see a turnaround or amelioration in a wide variety of these social, political, and economic conditions, some of which have been taken as symptomatic of a hardening social malaise. PMID:738471

  1. 76 FR 69292 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-08

    .... ML100920158), for which a notice of availability was published in the Federal Register on June 22, 2010 (75 FR... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY... Staff Guidance (LR-ISG), LR- ISG-2011-01, ``Aging Management of Stainless Steel Structures...

  2. 15 CFR 50.5 - Fee structure for age search and citizenship information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false Fee structure for age search and... THE CENSUS § 50.5 Fee structure for age search and citizenship information. Type of service Fee Searches of one census for one person and one transcript $65.00 Each additional copy of census transcript...

  3. 15 CFR 50.5 - Fee structure for age search and citizenship information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Fee structure for age search and... THE CENSUS § 50.5 Fee structure for age search and citizenship information. Type of service Fee Searches of one census for one person and one transcript $65.00 Each additional copy of census transcript...

  4. 15 CFR 50.5 - Fee structure for age search and citizenship information.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false Fee structure for age search and... THE CENSUS § 50.5 Fee structure for age search and citizenship information. Type of service Fee Searches of one census for one person and one transcript $65.00 Each additional copy of census transcript...

  5. 15 CFR 50.5 - Fee structure for age search and citizenship information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Fee structure for age search and... THE CENSUS § 50.5 Fee structure for age search and citizenship information. Type of service Fee Searches of one census for one person and one transcript $65.00 Each additional copy of census transcript...

  6. 15 CFR 50.5 - Fee structure for age search and citizenship information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... THE CENSUS § 50.5 Fee structure for age search and citizenship information. Type of service Fee... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Fee structure for age search and citizenship information. 50.5 Section 50.5 Commerce and Foreign Trade Regulations Relating to Commerce...

  7. 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

  8. School Finance Systems: Aging Structures in Need of Renovation.

    ERIC Educational Resources Information Center

    Odden, Allan; Clune, William H.

    1998-01-01

    Traditional school-finance systems need dramatic change to make them more supportive of the goals and strategies of standards. The shortcomings of current structures are reviewed, and suggestions are provided for changing finance structures, including a shift from fiscal equity toward educational adequacy. Elements to enhance a new system are…

  9. Parasitism in Children Aged Three Years and Under: Relationship between Infection and Growth in Rural Coastal Kenya

    PubMed Central

    McKibben, Maxim; Mungai, Peter; Muchiri, Eric M.; McKibben, Elisabeth; Gildengorin, Ginny; Sutherland, Laura J.; King, Charles H.; King, Christopher L.; Malhotra, Indu

    2015-01-01

    Background Parasitic infections, which are among the most common infections worldwide, disproportionately affect children; however, little is known about the impact of parasitic disease on growth in very early childhood. Our objective was to document the prevalence of parasitic infections and examine their association with growth during the first three years of life among children in coastal Kenya. Methodology/Principal Findings Children enrolled in a maternal-child cohort were tested for soil transmitted helminths (STHs: Ascaris, Trichuris, hookworm, Strongyloides), protozoa (malaria, Entamoeba histolytica and Giardia lamblia), filaria, and Schistosoma infection every six months from birth until age three years. Anthropometrics were measured at each visit. We used generalized estimating equation (GEE) models to examine the relationship between parasitic infections experienced in the first three years of life and growth outcomes (weight, length and head circumference). Of 545 children, STHs were the most common infection with 106 infections (19%) by age three years. Malaria followed in period prevalence with 68 infections (12%) by three years of age. Filaria and Schistosoma infection occurred in 26 (4.8%) and 16 (2.9%) children, respectively. Seven percent were infected with multiple parasites by three years of age. Each infection type (when all STHs were combined) was documented by six months of age. Decreases in growth of weight, length and head circumference during the first 36 months of life were associated with hookworm, Ascaris, E. histolytica, malaria and Schistosoma infection. In a subset analysis of 180 children who followed up at every visit through 24 months, infection with any parasite was associated with decelerations in weight, length and head circumference growth velocity. Multiple infections were associated with greater impairment of linear growth. Conclusions/Significance Our results demonstrate an under-recognized burden of parasitism in the first

  10. Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films

    NASA Astrophysics Data System (ADS)

    Burgess, J. A. J.; Holt, C. M. B.; Luber, E. J.; Fortin, D. C.; Popowich, G.; Zahiri, B.; Concepcion, P.; Mitlin, D.; Freeman, M. R.

    2016-08-01

    Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100‑xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections.

  11. Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films

    PubMed Central

    Burgess, J. A. J.; Holt, C. M. B.; Luber, E. J.; Fortin, D. C.; Popowich, G.; Zahiri, B.; Concepcion, P.; Mitlin, D.; Freeman, M. R.

    2016-01-01

    Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100−xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections. PMID:27498698

  12. The MARK-AGE phenotypic database: Structure and strategy.

    PubMed

    Moreno-Villanueva, María; Kötter, Tobias; Sindlinger, Thilo; Baur, Jennifer; Oehlke, Sebastian; Bürkle, Alexander; Berthold, Michael R

    2015-11-01

    In the context of the MARK-AGE study, anthropometric, clinical and social data as well as samples of venous blood, buccal mucosal cells and urine were systematically collected from 3337 volunteers. Information from about 500 standardised questions and about 500 analysed biomarkers needed to be documented per individual. On the one hand handling with such a vast amount of data necessitates the use of appropriate informatics tools and the establishment of a database. On the other hand personal information on subjects obtained as a result of such studies has, of course, to be kept confidential, and therefore the investigators must ensure that the subjects' anonymity will be maintained. Such secrecy obligation implies a well-designed and secure system for data storage. In order to fulfil the demands of the MARK-AGE study we established a phenotypic database for storing information on the study subjects by using a doubly coded system. PMID:25817205

  13. Mixing in age-structured population models of infectious diseases.

    PubMed

    Glasser, John; Feng, Zhilan; Moylan, Andrew; Del Valle, Sara; Castillo-Chavez, Carlos

    2012-01-01

    Infectious diseases are controlled by reducing pathogen replication within or transmission between hosts. Models can reliably evaluate alternative strategies for curtailing transmission, but only if interpersonal mixing is represented realistically. Compartmental modelers commonly use convex combinations of contacts within and among groups of similarly aged individuals, respectively termed preferential and proportionate mixing. Recently published face-to-face conversation and time-use studies suggest that parents and children and co-workers also mix preferentially. As indirect effects arise from the off-diagonal elements of mixing matrices, these observations are exceedingly important. Accordingly, we refined the formula published by Jacquez et al. [19] to account for these newly-observed patterns and estimated age-specific fractions of contacts with each preferred group. As the ages of contemporaries need not be identical nor those of parents and children to differ by exactly the generation time, we also estimated the variances of the Gaussian distributions with which we replaced the Kronecker delta commonly used in theoretical studies. Our formulae reproduce observed patterns and can be used, given contacts, to estimate probabilities of infection on contact, infection rates, and reproduction numbers. As examples, we illustrate these calculations for influenza based on "attack rates" from a prospective household study during the 1957 pandemic and for varicella based on cumulative incidence estimated from a cross-sectional serological survey conducted from 1988-94, together with contact rates from the several face-to-face conversation and time-use studies. Susceptibility to infection on contact generally declines with age, but may be elevated among adolescents and adults with young children. PMID:22037144

  14. Age structure of refractory interstellar dust and isotopic consequences

    NASA Technical Reports Server (NTRS)

    Clayton, Donald D.; Scowen, Paul; Liffman, Kurt

    1989-01-01

    A sputtering and recycling Monte Carlo model, developed by Liffman and Clayton (1988) is used to calculate the distribution of existence times of the matter in interstellar dust composed of refractory metals. The mean age of each dust particle is defined not as the time it has existed but rather as the mass-weighted existence times of its parts at t = 6 Gyr of the modeled solar system formation. It is shown that Galactic evolution generates a mean correlation, applying to large numbers of particles binned according to size rather than according to individual particles, whose mean ages fluctuate statistically. The cosmochemical consequence is that if interstellar particles can be dynamically sorted into separate size populations during the aggregation history of solar system bodies, the collections of larger grains will constitute matter that is chemically older than collections of smaller grains. The macroscopic age difference generates isotopic anomalies by virtue of the time dependence of the secondary/primary nucleosynthesis yields. Results are compared with three different prescriptions for the sputtering of interstellar dust.

  15. Secular Trends in Growth and Nutritional Status of Mozambican School-Aged Children and Adolescents

    PubMed Central

    dos Santos, Fernanda Karina; Maia, José A. R.; Gomes, Thayse Natacha Q. F.; Daca, Timóteo; Madeira, Aspacia; Katzmarzyk, Peter T.; Prista, António

    2014-01-01

    Objectives The purpose of this study was to examine secular changes in growth and nutritional status of Mozambican children and adolescents between 1992, 1999 and 2012. Methods 3374 subjects (1600 boys, 1774 girls), distributed across the three time points (523 subjects in 1992; 1565 in 1999; and 1286 in 2012), were studied. Height and weight were measured, BMI was computed, and WHO cut-points were used to define nutritional status. ANCOVA models were used to compare height, weight and BMI across study years; chi-square was used to determine differences in the nutritional status prevalence across the years. Results Significant differences for boys were found for height and weight (p<0.05) across the three time points, where those from 2012 were the heaviest, but those in 1999 were the tallest, and for BMI the highest value was observed in 2012 (1992<2012, 1999<2012). Among girls, those from 1999 were the tallest (1992<1999, 1999>2012), and those from 2012 had the highest BMI (1999<2012). In general, similar patterns were observed when mean values were analyzed by age. A positive trend was observed for overweight and obesity prevalences, whereas a negative trend emerged for wasting, stunting-wasting (in boys), and normal-weight (in girls); no clear trend was evident for stunting. Conclusion Significant positive changes in growth and nutritional status were observed among Mozambican youth from 1992 to 2012, which are associated with economic, social and cultural transitional processes, expressing a dual burden in this population, with reduction in malnourished youth in association with an increase in the prevalence of overweight and obesity. PMID:25473837

  16. Age-specific vibrissae growth rates: a tool for determining the timing of ecologically important events in Steller sea lions

    USGS Publications Warehouse

    Rea, L.D.; Christ, A.M.; Hayden, A.B.; Stegall, V.K.; Farley, S.D.; Stricker, Craig A.; Mellish, J.E.; Maniscalco, J.M.; Waite, J.N.; Burkanov, V.N.; Pitcher, K.W.

    2015-01-01

    Steller sea lions (SSL; Eumetopias jubatus) grow their vibrissae continually, providing a multiyear record suitable for ecological and physiological studies based on stable isotopes. An accurate age-specific vibrissae growth rate is essential for registering a chronology along the length of the record, and for interpreting the timing of ecologically important events. We utilized four methods to estimate the growth rate of vibrissae in fetal, rookery pup, young-of-the-year (YOY), yearling, subadult, and adult SSL. The majority of vibrissae were collected from SSL live-captured in Alaska and Russia between 2000 and 2013 (n = 1,115), however, vibrissae were also collected from six adult SSL found dead on haul-outs and rookeries during field excursions to increase the sample size of this underrepresented age group. Growth rates of vibrissae were generally slower in adult (0.44 ± 0.15 cm/mo) and subadult (0.61 ± 0.10 cm/mo) SSL than in YOY (0.87 ± 0.28 cm/mo) and fetal (0.73 ± 0.05 cm/mo) animals, but there was high individual variability in these growth rates within each age group. Some variability in vibrissae growth rates was attributed to the somatic growth rate of YOY sea lions between capture events (P = 0.014, r2 = 0.206, n = 29).

  17. Aging.

    PubMed

    Park, Dong Choon; Yeo, Seung Geun

    2013-09-01

    Aging is initiated based on genetic and environmental factors that operate from the time of birth of organisms. Aging induces physiological phenomena such as reduction of cell counts, deterioration of tissue proteins, tissue atrophy, a decrease of the metabolic rate, reduction of body fluids, and calcium metabolism abnormalities, with final progression onto pathological aging. Despite the efforts from many researchers, the progression and the mechanisms of aging are not clearly understood yet. Therefore, the authors would like to introduce several theories which have gained attentions among the published theories up to date; genetic program theory, wear-and-tear theory, telomere theory, endocrine theory, DNA damage hypothesis, error catastrophe theory, the rate of living theory, mitochondrial theory, and free radical theory. Although there have been many studies that have tried to prevent aging and prolong life, here we introduce a couple of theories which have been proven more or less; food, exercise, and diet restriction. PMID:24653904

  18. Aging

    PubMed Central

    Park, Dong Choon

    2013-01-01

    Aging is initiated based on genetic and environmental factors that operate from the time of birth of organisms. Aging induces physiological phenomena such as reduction of cell counts, deterioration of tissue proteins, tissue atrophy, a decrease of the metabolic rate, reduction of body fluids, and calcium metabolism abnormalities, with final progression onto pathological aging. Despite the efforts from many researchers, the progression and the mechanisms of aging are not clearly understood yet. Therefore, the authors would like to introduce several theories which have gained attentions among the published theories up to date; genetic program theory, wear-and-tear theory, telomere theory, endocrine theory, DNA damage hypothesis, error catastrophe theory, the rate of living theory, mitochondrial theory, and free radical theory. Although there have been many studies that have tried to prevent aging and prolong life, here we introduce a couple of theories which have been proven more or less; food, exercise, and diet restriction. PMID:24653904

  19. Serum vascular endothelial growth factor receptor-2 and adropin levels in age-related macular degeneration

    PubMed Central

    Örnek, Nurgül; Örnek, Kemal; Aydin, Süleyman; Yilmaz, Musa; Ölmez, Yaşar

    2016-01-01

    AIM To investigate the serum levels of vascular endothelial growth factor receptor-2 (VEGFR-2) and adropin in age-related macular degeneration (AMD) patients. METHODS Ninety-eight AMD patients were included in the study. Seventy-eight age- and sex-matched healthy volunteers were recruited as the control group. Fundus florescein angiography and optical coherence tomography were performed to assess the posterior segment details. Serum VEGFR-2 and adropin levels were measured using enzyme-linked immunosorbent assays and compared between the study groups. RESULTS AMD group had significantly increased foveal retinal thickness, serum LDL and HDL levels and significantly decreased subfoveal choroidal thickness (P =0.01, 0.047, 0.025 and <0.001, respectively). Serum VEGFR-2 level revealed a significant decrease in AMD patients compared to controls (26.48±6.44 vs 30.42±7.92 ng/mL, P<0.001). There was an insignificant increase in serum adropin level in AMD patients (6.17±3.19 vs 5.79±2.71 ng/mL, P=0.4). Serum level of VEGFR-2 in AMD patients had a significant negative correlation with foveal retinal thickness (r=-0.226, P=0.025) and a significant positive correlation with subfoveal choroidal thickness (r=0.2, P=0.048). CONCLUSION The current study demonstrated that the decreased serum VEGFR-2 level may be considered in the development of AMD. Adropin does not seem to play a role in the pathogenesis of AMD. PMID:27162728

  20. Reproductive performance of high growth rate gilts inseminated at an early age.

    PubMed

    Kummer, Rafael; Bernardi, Mari Lourdes; Wentz, Ivo; Bortolozzo, Fernando Pandolfo

    2006-11-01

    The aim of this work was to determine if gilts, which have a high growth rate (GR) could be mated earlier without reducing the reproductive performance or increasing the culling rate up to the third parity. Gilts of Camborough 22 (C22, n=568) breeding were mated and allocated into three groups according to weight and age on the insemination day. G1 (n=164)-gilts with a GR>or=700 g/d and inseminated at <210 d. G2 (n=165)-gilts with a GR>or=700 g/d and inseminated at >or=210 d. G3 (n=239)-gilts with a GR<700 g/d and inseminated at >or=210 d. All females were fed ad libitum from 150 d on and were inseminated at their second estrus or later. The minimum weight at mating was 127 kg. Three parities were studied, with farrowing rate, litter size and culling rate being compared. At the first parity, G2 gilts produced, on average, one more piglet than the other groups (P<0.05). However, when analyzing three parities, there were no differences in total born (11.6 x 12.3 x 11.7), farrowing rate (87.1% x 88.7% x 89.8%) and culling rate (30.2% x 25.3% x 28.2%) among G1-G3 groups, respectively (P>0.05). In conclusion, gilts, which had a minimum weight of 127 kg can be inseminated at their second or greater estrus, between 185 and <210 d of age, without impairing their productive performance over three parities. PMID:16431043

  1. Impact of Neonatal Growth on IQ and Behavior at Early School Age

    PubMed Central

    Lynch, John W.; Yang, Seungmi; Dahhou, Mourad; Kramer, Michael S.

    2013-01-01

    OBJECTIVES: The objective was to examine associations of neonatal weight gain (NWG) and head circumference gain (HCG) with IQ scores and behavior at early school age. METHODS: We used data from the Promotion of Breastfeeding Intervention Trial, involving Belarusian infants born full term and weighing ≥2500 g. NWG and HCG were measured as the percentage gain in weight and head circumference over the first 4 weeks relative to birth size. IQ and behavior were measured at 6.5 years of age by using the Wechsler Abbreviated Scales of Intelligence and the Strengths and Difficulties Questionnaire (SDQ), respectively, with SDQ collected from parents and teachers. The associations between the exposures (NWG, HCG) and children’s IQ and SDQ were examined by using mixed models to account for clustering of measurements, and adjustment for potentially confounding perinatal and socioeconomic factors. RESULTS: Mean NWG was 26% (SD 10%) of birth weight. In fully adjusted models, infants in the highest versus lowest quartile of NWG had 1.5-point (95% confidence interval [CI] 0.8 to 2.2) higher IQ scores (n = 13 840). A weak negative (protective) association between NWG and SDQ total difficulties scores was observed for the teacher-reported (β = −0.39, 95% CI −0.71 to −0.08, n = 12 016), but not the parent-reported (β = −0.12, 95% CI −0.39 to 0.15, n = 13 815), SDQ. Similar associations were observed with HCG and IQ and behavior. CONCLUSIONS: Faster gains in weight or head circumference in the 4 weeks after birth may contribute to children’s IQ, but reverse causality (brain function affects neonatal growth) cannot be excluded. PMID:23776123

  2. 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

  3. Efficacy of calcein and Coomassie Blue dyeing of shell growing-edges and micro growth-bands: ageing juvenile of Pinctada mazatlanica (Pterioida: Pteriidae).

    PubMed

    Loria, Patricia L McCoy; Huato-Soberanis, Leonardo

    2014-09-01

    Age validation is the first step to determine shellfish species age determination. This information is vital for different inferential models used in marine ecosystem management activities. In spite that various validation techniques are used for marking carbon calcium structures, the calcein marking technique for oysters had never been used for age validation in Pinctada mazatlanica. Thus the objectives of this study included: the evaluation of calcein to mark a shell growing-edge, and the efficacy of Coomassie Blue staining on posterior shell growth, to produce visible micro growth-bands that would enable age validation of juvenile mother-of-pearl oysters. Oysters were collected and cultivated at The Perlas del Cortez S. de R. L. MI. pearl-farming operation, in Pichilingue, La Paz Bay, Baja California Sur, Mexico; a total of 36 oysters (shell height 11.5-36.4 mm) were injected with calcein (0.125 g/L), and another 50 oysters (shell height 14.8-42.7 mm) were submersed in calcein (0.4 and 0.7 g/L). Shell slices of calcein-marked oysters were posteriourly stained with Coomassie Blue R-25 for micro growth-band recognition. Our results showed that Calcein marking only worked by submersion and produced a concise bright lime-green florescent band along the growing-edge with clear boundaries for both concentrations. However, marks resulted better at the lower calcein concentration (0.4 g/L) with more "perfect" and "good" marks on the growing-edge (p = 0.0012). Commassie Blue staining technique was successful, and allowed to conclude that one micro growth-band was laid down per day, similar to other oyster species. Mean 15-d increment of shell growth height was slightly greater at the lower calcein concentration (= 0.735 mm) than at the higher one (= 0.577 mm) (not significant difference, p = 0.198). Calcein marking of shell growing-edges and Commassie Blue staining of posterior shell growth, as a method for age validation is recommended for shellfish shell growth

  4. Radiostratigraphy and age structure of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    MacGregor, Joseph A.; Fahnestock, Mark A.; Catania, Ginny A.; Paden, John D.; Prasad Gogineni, S.; Young, S. Keith; Rybarski, Susan C.; Mabrey, Alexandria N.; Wagman, Benjamin M.; Morlighem, Mathieu

    2015-02-01

    Several decades of ice-penetrating radar surveys of the Greenland and Antarctic ice sheets have observed numerous widespread internal reflections. Analysis of this radiostratigraphy has produced valuable insights into ice sheet dynamics and motivates additional mapping of these reflections. Here we present a comprehensive deep radiostratigraphy of the Greenland Ice Sheet from airborne deep ice-penetrating radar data collected over Greenland by The University of Kansas between 1993 and 2013. To map this radiostratigraphy efficiently, we developed new techniques for predicting reflection slope from the phase recorded by coherent radars. When integrated along track, these slope fields predict the radiostratigraphy and simplify semiautomatic reflection tracing. Core-intersecting reflections were dated using synchronized depth-age relationships for six deep ice cores. Additional reflections were dated by matching reflections between transects and by extending reflection-inferred depth-age relationships using the local effective vertical strain rate. The oldest reflections, dating to the Eemian period, are found mostly in the northern part of the ice sheet. Within the onset regions of several fast-flowing outlet glaciers and ice streams, reflections typically do not conform to the bed topography. Disrupted radiostratigraphy is also observed in a region north of the Northeast Greenland Ice Stream that is not presently flowing rapidly. Dated reflections are used to generate a gridded age volume for most of the ice sheet and also to determine the depths of key climate transitions that were not observed directly. This radiostratigraphy provides a new constraint on the dynamics and history of the Greenland Ice Sheet.

  5. Radiostratigraphy and age structure of the Greenland Ice Sheet

    PubMed Central

    MacGregor, Joseph A; Fahnestock, Mark A; Catania, Ginny A; Paden, John D; Prasad Gogineni, S; Young, S Keith; Rybarski, Susan C; Mabrey, Alexandria N; Wagman, Benjamin M; Morlighem, Mathieu

    2015-01-01

    Several decades of ice-penetrating radar surveys of the Greenland and Antarctic ice sheets have observed numerous widespread internal reflections. Analysis of this radiostratigraphy has produced valuable insights into ice sheet dynamics and motivates additional mapping of these reflections. Here we present a comprehensive deep radiostratigraphy of the Greenland Ice Sheet from airborne deep ice-penetrating radar data collected over Greenland by The University of Kansas between 1993 and 2013. To map this radiostratigraphy efficiently, we developed new techniques for predicting reflection slope from the phase recorded by coherent radars. When integrated along track, these slope fields predict the radiostratigraphy and simplify semiautomatic reflection tracing. Core-intersecting reflections were dated using synchronized depth-age relationships for six deep ice cores. Additional reflections were dated by matching reflections between transects and by extending reflection-inferred depth-age relationships using the local effective vertical strain rate. The oldest reflections, dating to the Eemian period, are found mostly in the northern part of the ice sheet. Within the onset regions of several fast-flowing outlet glaciers and ice streams, reflections typically do not conform to the bed topography. Disrupted radiostratigraphy is also observed in a region north of the Northeast Greenland Ice Stream that is not presently flowing rapidly. Dated reflections are used to generate a gridded age volume for most of the ice sheet and also to determine the depths of key climate transitions that were not observed directly. This radiostratigraphy provides a new constraint on the dynamics and history of the Greenland Ice Sheet. Key Points Phase information predicts reflection slope and simplifies reflection tracing Reflections can be dated away from ice cores using a simple ice flow model Radiostratigraphy is often disrupted near the onset of fast ice flow PMID:26213664

  6. Effect of the severe plastic deformation and aging temperature on the strengthening, structure, and wear resistance of a beryllium bronze

    NASA Astrophysics Data System (ADS)

    Korshunov, L. G.; Korznikov, A. V.; Chernenko, N. L.

    2011-04-01

    The effect of the aging temperature, severe plastic deformation by equal-channel angular (ECA) pressing at 400°C, and subsequent aging on the rate of wear, friction coefficient, and microhardness of a commercial beryllium bronze Br.B2 quenched from 800°C has been investigated. The bronze structure before and after tribological tests has been studied with the help of metallographic and electron-microscopic methods of analysis. It has been shown that tempering (aging) of the bronze at 250-400°C for 3 h leading to a sharp growth of the hardness substantially increases the wear rate of the bronze in pair with the steel 45 under the conditions of both dry and boundary sliding friction. The cause of this is a decrease in the toughness of the surface layer of the bronze due to the precipitation of particles of the strengthening γ' phase (CuBe) from the α solid solution. Severe plastic deformation (ECA pressing) markedly enhances the wear resistance of the bronze subjected to subsequent aging at 250-400°C. This is because ECA pressing favors the formation of an extremely dispersed nanocrystalline structure with α-phase crystals 40-50 nm in size at the wear surface of the bronze; whereas in the friction zone of the quenched bronze or the quenched and aged bronze, there arises a significantly less dispersed structure with matrix crystals to 300 nm in size. It has been assumed that under conditions of the rotational mechanism of plastic deformation operating upon sliding friction in the near-surface layer of the bronze, the increase in dispersity of its structure attained by using ECA pressing enhances the toughness and, correspondingly, wear resistance of the aged bronze.

  7. Polypeptide Chirality Influences Multilayer Thin Film Growth and Structure

    NASA Astrophysics Data System (ADS)

    Bell, Zephra; Khadka, Dhan; Haynie, Donald

    2011-03-01

    Polypeptide multilayer thin films are being developed for a variety of applications.These include coatings for implant devices and systems for drug delivery in thebiomedical sciences, and optical coatings. Subsequent polymer adsorption steps involve polymers of opposite polarity. Here, the polymers were polypeptides. This project compared the consequences of changing polypeptide chirality on film growth and structure. The peptides were poly(L-glutamic acid), its right-handed counterpart, poly(D-glutamic acid), and poly(lysine-tyrosine). The first two are negatively charged at neutral pH, the third one is positively charged. Poly(lysine-tyrosine)/poly(L-glutamic acid) films and poly(lysine-tyrosine)/poly(D-glutamic acid) films werefabricated on 1 mm-thick quartz plates. In one experiment, films were grown to 34layers. The UV absorption spectrum was taken after each layer deposited to determinethe rate of polymer self-assembly. Separately, UV or visible wavelength spectra wereobtained for films stained with a dye cooled/heated in the range 4-65 °C. In anotherexperiment, a mixture of poly-L-glutamic acid and poly-D-glutamic acid was used as thepolyanion for film buildup. The data show that poly(lysine-tyrosine)/poly(L-glutamicacid) films built up at a higher rate than the corresponding right-handed films.

  8. A tropical freshwater wetlands: I. Structure, growth, and regeneration

    USGS Publications Warehouse

    Allen, J.A.; Krauss, K.W.; Ewel, K.C.; Keeland, B.D.; Waguk, E.E.

    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 regeneration on two sites each on Nansepsep and Inkosr soils and one site on the much less common Sonahnpil soil type. Terminalia tree sizes were similar on all three soil types, but forests differed in total basal area, species of smaller trees, and total plant species diversity. Terminalia regeneration was found only on the Inkosr soil type, which had the highest water table levels. Other Terminalia species are relatively light demanding, and T. carolinensis exhibited similar characteristics. It is therefore likely that Terminalia requires periodic, but perhaps naturally rare, stand-replacing disturbances (e.g., typhoons) in order to maintain its dominanace, except on the wettest sites, where competition from other species is reduced. Terminalia swamps in the Nansepsep soil type appeared to be at the greatest risk of conversion to other uses, but swamps on all three types may face reater pressure as Kosrae's population increases and the island's infrastrucure becomes more developed.

  9. Longitudinal study of growth of children with unilateral cleft lip and palate: 2 to 10 years of age.

    PubMed

    Marques, Ilza Lazarini; Nackashi, John; Borgo, Hilton Coimbra; Martinelli, Angela Patrícia Menezes Cardoso; de Souza, Luiz; Dutka, Jeniffer de Cássia Rillo; Williams, William N; Pegoraro-Krook, Maria Inês

    2015-03-01

    Objective : To study the growth of children with complete unilateral cleft lip and palate (UCLP) from 2 to 10 years of age and to assess whether growth varied from that of children without UCLP (typical children). Design : Physical growth was one of the outcome measures of a National Institutes of Health-sponsored longitudinal, prospective clinical trial conducted by the University of Florida and the University of São Paulo. Setting : Hospital of Rehabilitation of Craniofacial Anomalies, University of São Paulo (HRAC-USP), Bauru, Brazil. Main Outcome Measures : Height and weight were prospectively measured for 360 healthy children with UCLP who were nonsyndromic, belonged to median socioeconomic status, and received health care at HRAC-USP. To compare growth of children with UCLP to that of typical children, growth curves for UCLP were developed and compared with World Health Organization curves for 2006 and 2007, which were used as reference for typical children. Third-degree polynomials were used to explain the relationship of length and weight with age. Confidence limits of 95% were used for the mean curve using the statistic Z ~ N (0,1). Results : Children with UCLP from 2 to 10 years old presented height and weight growth curves similar to those of typical children for both genders. Conclusion : Children with UCLP from 2 to 10 years old presented physical growth similar to that of typical children. PMID:24810484

  10. 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

  11. Immune physiology in tissue regeneration and aging, tumor growth, and regenerative medicine

    PubMed Central

    Bukovsky, Antonin; Caudle, Michael R.; Carson, Ray J.; Gaytán, Francisco; Huleihel, Mahmoud; Kruse, Andrea; Schatten, Heide; Telleria, Carlos M.

    2009-01-01

    The immune system plays an important role in immunity (immune surveillance), but also in the regulation of tissue homeostasis (immune physiology). Lessons from the female reproductive tract indicate that immune system related cells, such as intraepithelial T cells and monocyte-derived cells (MDC) in stratified epithelium, interact amongst themselves and degenerate whereas epithelial cells proliferate and differentiate. In adult ovaries, MDC and T cells are present during oocyte renewal from ovarian stem cells. Activated MDC are also associated with follicular development and atresia, and corpus luteum differentiation. Corpus luteum demise resembles rejection of a graft since it is attended by a massive influx of MDC and T cells resulting in parenchymal and vascular regression. Vascular pericytes play important roles in immune physiology, and their activities (including secretion of the Thy-1 differentiation protein) can be regulated by vascular autonomic innervation. In tumors, MDC regulate proliferation of neoplastic cells and angiogenesis. Tumor infiltrating T cells die among malignant cells. Alterations of immune physiology can result in pathology, such as autoimmune, metabolic, and degenerative diseases, but also in infertility and intrauterine growth retardation, fetal morbidity and mortality. Animal experiments indicate that modification of tissue differentiation (retardation or acceleration) during immune adaptation can cause malfunction (persistent immaturity or premature aging) of such tissue during adulthood. Thus successful stem cell therapy will depend on immune physiology in targeted tissues. From this point of view, regenerative medicine is more likely to be successful in acute rather than chronic tissue disorders. PMID:20195382

  12. AGE-RELATED DEGRADATION OF NUCLEAR POWER PLANT STRUCTURES AND COMPONENTS.

    SciTech Connect

    BRAVERMAN,J.

    1999-03-29

    This paper summarizes and highlights the results of the initial phase of a research project on the assessment of aged and degraded structures and components important to the safe operation of nuclear power plants (NPPs). A review of age-related degradation of structures and passive components at NPPs was performed. Instances of age-related degradation have been collected and reviewed. Data were collected from plant generated documents such as Licensing Event Reports, NRC generic communications, NUREGs and industry reports. Applicable cases of degradation occurrences were reviewed and then entered into a computerized database. The results obtained from the review of degradation occurrences are summarized and discussed. Various trending analyses were performed to identify which structures and components are most affected, whether degradation occurrences are worsening, and what are the most common aging mechanisms. The paper also discusses potential aging issues and degradation-susceptible structures and passive components which would have the greatest impact on plant risk.

  13. Age-Related Degradation of Nuclear Power Plant Structures and Components

    SciTech Connect

    Braverman, J.; Chang, T.-Y.; Chokshi, N.; Hofmayer, C.; Morante, R.; Shteyngart, S.

    1999-03-29

    This paper summarizes and highlights the results of the initial phase of a research project on the assessment of aged and degraded structures and components important to the safe operation of nuclear power plants (NPPs). A review of age-related degradation of structures and passive components at NPPs was performed. Instances of age-related degradation have been collected and reviewed. Data were collected from plant generated documents such as Licensing Event Reports, NRC generic communications, NUREGs and industry reports. Applicable cases of degradation occurrences were reviewed and then entered into a computerized database. The results obtained from the review of degradation occurrences are summarized and discussed. Various trending analyses were performed to identify which structures and components are most affected, whether degradation occurrences are worsening, and what was the most common aging mechanisms. The paper also discusses potential aging issues and degradation-susceptible structures and passive components which would have the greatest impact on plant risk.

  14. Depressing effect of 0.1 wt.% Cr addition into Sn-9Zn solder alloy on the intermetallic growth with Cu substrate during isothermal aging

    SciTech Connect

    Hu Jin; Hu Anmin; Li Ming; Mao Dali

    2010-03-15

    In this paper, the effect of 0.1 wt.% Cr addition into Sn-9Zn lead-free solder alloys on the growth of intermetallic compound (IMC) with Cu substrate during soldering and subsequent isothermal aging was investigated. During soldering, it was found that 0.1 wt.% Cr addition did not contribute to forming the IMC, which was verified as the same phase structure as the IMC for Sn-9Zn/Cu. However, during solid-state isothermal aging, the IMC growth was remarkably depressed by 0.1 wt.% Cr addition in the Sn-9Zn solder, and this effect tended to be more prominent at higher aging temperature. The activation energy for IMC growth was determined as 21.2 kJ mol{sup -1} and 42.9 kJ mol{sup -1} for Sn-9Zn/Cu and Sn-9Zn-Cr/Cu, respectively. The reduced diffusion coefficient was confirmed for the 0.1Cr-containing solder/Cu. Energy-dispersive X-ray mapping and point analysis also showed ZnCr phase existing in solder matrix, which can reduce diffusion rate of Zn atoms.

  15. The 1991 International Conference on Aging Aircraft and Structural Airworthiness

    NASA Technical Reports Server (NTRS)

    Harris, Charles E. (Editor)

    1992-01-01

    Technical sessions of the conference included structural performance, nondestructive evaluation, maintenance and repair, international activities, and commuter airlines. Each session was organized to provide a well-rounded view of the subject from the industry, regulatory, and research perspective. Thirty-four presentations were given by the international technical community.

  16. Discrete limit and monotonicity properties of the Floquet eigenvalue in an age structured cell division cycle model.

    PubMed

    Gaubert, Stéphane; Lepoutre, Thomas

    2015-12-01

    We consider a cell population described by an age-structured partial differential equation with time periodic coefficients. We assume that division only occurs within certain time intervals at a rate [Formula: see text] for cells who have reached minimal positive age (maturation). We study the asymptotic behavior of the dominant Floquet eigenvalue, or Perron-Frobenius eigenvalue, representing the growth rate, as a function of the maturation age, when the division rate [Formula: see text] tends to infinity (divisions become instantaneous). We show that the dominant Floquet eigenvalue converges to a staircase function with an infinite number of steps, determined by a discrete dynamical system. This indicates that, in the limit, the growth rate is governed by synchronization phenomena between the maturation age and the length of the time intervals in which division may occur. As an intermediate result, we give a sufficient condition which guarantees that the dominant Floquet eigenvalue is a nondecreasing function of the division rate. We also give a counter example showing that the latter monotonicity property does not hold in general. PMID:25814336

  17. Dangling bond deflection model: Growth of gel network with loop structure

    NASA Astrophysics Data System (ADS)

    Ma, Hang-Shing; Jullien, Rémi; Scherer, George W.

    2002-04-01

    It has been shown that the closed-loop structure in the model gel networks is responsible for their stiffness. However, the creation of loops has been underestimated in most of the existing kinetic aggregation models [e.g., DLCA (diffusion-limited cluster-cluster aggregation) and derivatives]. A dangling bond deflection (DEF) mechanism is proposed to model the fluctuation of dangling branches or dead ends under thermal excitation. The random deflections of the dangling branches can create loops in the network by forming intracluster bonds, and proceed during both the gelling and aging processes. The resulting DLCADEF networks have extensive loop structure with a negligible number of dangling branches. Its growth kinetics and fractal behavior resemble those of real gels, including volume-invariant gel time and fractal dimension of about 2. The DLCADEF model is the first attempt to model the gel growth with loop formation by the physically realistic fluctuation mechanism. The mechanical properties of the resulting networks will be studied and verified by comparison with real gels.

  18. Age and growth of chub mackerel ( Xcomber japonicus) in the East China and Yellow Seas using sectioned otolith samples

    NASA Astrophysics Data System (ADS)

    Li, Gang; Chen, Xinjun; Feng, Bo

    2008-11-01

    Although chub mackerel ( Scomber japonicus) is a primary pelagic fish species, we have only limited knowledge on its key life history processes. The present work studied the age and growth of chub mackerel in the East China and Yellow Seas. Age was determined by interpreting and counting growth rings on the sagitta otoliths of 252 adult fish caught by the Chinese commercial purse seine fleet during the period from November 2006 to January 2007 and 150 juveniles from bottom trawl surveys on the spawning ground in May 2006. The difference between the assumed birth date of 1st April and date of capture was used to adjust the age determined from counting the number of complete translucent rings. The parameters of three commonly used growth models, the von Bertalanffy, Logistic and Gompertz models, were estimated using the maximum likelihood method. Based on the Akaike Information Criterion ( AIC), the von Bertalanffy growth model was found to be the most appropriate model. The size-at-age and size-at-maturity values were also found to decrease greatly compared with the results achieved in the 1950s, which was caused by heavy exploitation over the last few decades.

  19. Math Growth Trajectories of Students with Disabilities: Disability Category, Gender, Racial, and Socioeconomic Status Differences from Ages 7 to 17

    ERIC Educational Resources Information Center

    Wei, Xin; Lenz, Keith B.; Blackorby, Jose

    2013-01-01

    This study examined math growth trajectories by disability category, gender, race, and socioeconomic status using a nationally representative sample of students ages 7 to 17. The students represented 11 federal disability categories. Compared with the national norming sample, students in all 11 disability categories had lower math achievement…

  20. Role of physical activity and sleep duration in growth and body composition of preschool-aged children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of physical activity patterns and sleep duration on growth and body composition of preschool-aged children remains unresolved. Aims were (1) to delineate cross-sectional associations among physical activity components, sleep, total energy expenditure (TEE), and body size and composition; ...

  1. 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. PMID:18785651

  2. Interplay between Shear Loading and Structural Aging in a Physical Gelatin Gel

    SciTech Connect

    Ronsin, O.; Caroli, C.; Baumberger, T.

    2009-09-25

    We show that the aging of the mechanical relaxation of a gelatin gel exhibits the same scaling phenomenology as polymer and colloidal glasses. In addition, gelatin is known to exhibit logarithmic structural aging (stiffening). We find that stress accelerates this process. However, this effect is definitely irreducible to a mere age shift with respect to natural aging. We suggest that it is interpretable in terms of elastically aided elementary (coil->helix) local events whose dynamics gradually slows down as aging increases geometric frustration.

  3. Continuous Age-Structured Model for Bovine Tuberculosis in African buffalo

    NASA Astrophysics Data System (ADS)

    Anguelov, R.; Kojouharov, H.

    2009-10-01

    The paper deals with a model of the spread of bovine tuberculosis in the buffalo population in the Kruger National Park in South Africa. The model uses continuous age structure and it is formulated in terms of partial differential equations using eight epidemiological classes (compartments). More precisely, the age density for each class at time t satisfies a one way wave equation, where the age is the space variable. The continuous age model discussed here is derived from a 2006 age groups model by P. C. Cross and W. M. Getz.

  4. Structural damages of maxillofacial biopolymers under solar aging.

    PubMed

    Eleni, P N; Krokida, M K; Frangou, M J; Polyzois, G L; Maroulis, Z B; Marinos-Kouris, D

    2007-09-01

    Additional types of silicone biopolymers are widely used in maxillofacial prosthetics. Therefore, the knowledge of the solar radiation's effect on their structural stability is highly important. Four different industrially synthesized biomaterials were examined, called Episil Europe 1, Europe 2, Europe 3 and Africa 3, which were exposed to solar radiation (UVA, UVB) for eight different time periods (from 8 to 168 h). Structural damages due to irradiation exposure were investigated by mechanical tests (compression) and differential scanning calorimetry (DSC) methods. Simple mathematical models were developed, containing parameters with physical meaning such as maximum stress (sigma(max)), maximum strain (epsilon), elasticity parameter (E), and viscoelastic parameter (p), for the compression test, and melting temperature (T (m)) and Enthalpy in melting point (Heat) for DSC. With increasing irradiation time their maximum stress and strain decreased significantly, and the materials lost their elasticity and molecular stability. A decrement in their melting points and heats was observed as irradiation time was increasing. Finally, experimental results demonstrated that solar radiation has a severe effect on the structural stability of the examined biomaterials. PMID:17483904

  5. Geroprotectors.org: a new, structured and curated database of current therapeutic interventions in aging and age-related disease

    PubMed Central

    Moskalev, Alexey; Chernyagina, Elizaveta; de Magalhães, João Pedro; Barardo, Diogo; Thoppil, Harikrishnan; Shaposhnikov, Mikhail; Budovsky, Arie; Fraifeld, Vadim E.; Garazha, Andrew; Tsvetkov, Vasily; Bronovitsky, Evgeny; Bogomolov, Vladislav; Scerbacov, Alexei; Kuryan, Oleg; Gurinovich, Roman; Jellen, Leslie C.; Kennedy, Brian; Mamoshina, Polina; Dobrovolskaya, Evgeniya; Aliper, Alex; Kaminsky, Dmitry; Zhavoronkov, Alex

    2015-01-01

    As the level of interest in aging research increases, there is a growing number of geroprotectors, or therapeutic interventions that aim to extend the healthy lifespan and repair or reduce aging-related damage in model organisms and, eventually, in humans. There is a clear need for a manually-curated database of geroprotectors to compile and index their effects on aging and age-related diseases and link these effects to relevant studies and multiple biochemical and drug databases. Here, we introduce the first such resource, Geroprotectors (http://geroprotectors.org). Geroprotectors is a public, rapidly explorable database that catalogs over 250 experiments involving over 200 known or candidate geroprotectors that extend lifespan in model organisms. Each compound has a comprehensive profile complete with biochemistry, mechanisms, and lifespan effects in various model organisms, along with information ranging from chemical structure, side effects, and toxicity to FDA drug status. These are presented in a visually intuitive, efficient framework fit for casual browsing or in-depth research alike. Data are linked to the source studies or databases, providing quick and convenient access to original data. The Geroprotectors database facilitates cross-study, cross-organism, and cross-discipline analysis and saves countless hours of inefficient literature and web searching. Geroprotectors is a one-stop, knowledge-sharing, time-saving resource for researchers seeking healthy aging solutions. PMID:26342919

  6. Effect of aging on the fatigue crack growth kinetics of an Al-Zn-Mg-Cu alloy in two directions

    SciTech Connect

    Alpay, S.P.; Guerbuez, R. . Dept. of Metallurgical Engineering)

    1994-02-15

    There have been investigations discussing the effect of aging condition, and thereby the microstructure, on the fatigue crack growth characteristics of precipitation hardening alloys. Lindigkeit et al.., testing an Al-Zn-Mg-Cu alloy of composition corresponding to the commercial alloy 7075 concluded that the crack propagation resistance of underaged microstructures with shearable precipitates is significantly higher than overaged samples of same strength containing non-shearable particles. They reported that this behavior cannot be explained on the basis of slip reversibility alone. A similar conclusion is drawn by Zaiken and Ritchie from investigations on the effect of microstructure on the fatigue crack growth rate of an 7150 aluminum alloy, which is a somewhat high-purity version of the alloy 7050, with lower Fe and Si contents. It is also interesting that aging conditions showing high resistance to fatigue crack growth at low [Delta]K regimes, do not necessarily retain their superiority at medium and high stress intensity ranges.

  7. Characterizing structural association alterations within brain networks in normal aging using Gaussian Bayesian networks

    PubMed Central

    Guo, Xiaojuan; Wang, Yan; Chen, Kewei; Wu, Xia; Zhang, Jiacai; Li, Ke; Jin, Zhen; Yao, Li

    2014-01-01

    Recent multivariate neuroimaging studies have revealed aging-related alterations in brain structural networks. However, the sensory/motor networks such as the auditory, visual and motor networks, have obtained much less attention in normal aging research. In this study, we used Gaussian Bayesian networks (BN), an approach investigating possible inter-regional directed relationship, to characterize aging effects on structural associations between core brain regions within each of these structural sensory/motor networks using volumetric MRI data. We then further examined the discriminability of BN models for the young (N = 109; mean age =22.73 years, range 20–28) and old (N = 82; mean age =74.37 years, range 60–90) groups. The results of the BN modeling demonstrated that structural associations exist between two homotopic brain regions from the left and right hemispheres in each of the three networks. In particular, compared with the young group, the old group had significant connection reductions in each of the three networks and lesser connection numbers in the visual network. Moreover, it was found that the aging-related BN models could distinguish the young and old individuals with 90.05, 73.82, and 88.48% accuracy for the auditory, visual, and motor networks, respectively. Our findings suggest that BN models can be used to investigate the normal aging process with reliable statistical power. Moreover, these differences in structural inter-regional interactions may help elucidate the neuronal mechanism of anatomical changes in normal aging. PMID:25324771

  8. Effects of Resveratrol Supplementation on Bone Growth in Young Rats and Microarchitecture and Remodeling in Ageing Rats

    PubMed Central

    Lee, Alice M. C.; Shandala, Tetyana; Nguyen, Long; Muhlhausler, Beverly S.; Chen, Ke-Ming; Howe, Peter R.; Xian, Cory J.

    2014-01-01

    Osteoporosis is a highly prevalent skeletal disorder in the elderly that causes serious bone fractures. Peak bone mass achieved at adolescence has been shown to predict bone mass and osteoporosis related risk fracture later in life. Resveratrol, a natural polyphenol compound, may have the potential to promote bone formation and reduce bone resorption. However, it is unclear whether it can aid bone growth and bone mass accumulation during rapid growth and modulate bone metabolism during ageing. Using rat models, the current study investigated the potential effects of resveratrol supplementation during the rapid postnatal growth period and in late adulthood (early ageing) on bone microarchitecture and metabolism. In the growth trial, 4-week-old male hooded Wistar rats on a normal chow diet were given resveratrol (2.5 mg/kg/day) or vehicle control for 5 weeks. In the ageing trial, 6-month-old male hooded Wistar rats were treated with resveratrol (20 mg/kg/day) or vehicle for 3 months. Treatment effects in the tibia were examined by μ-computer tomography (μ-CT) analysis, bone histomorphometric measurements and reverse transcription-polymerase chain reaction (RT-PCR) gene expression analysis. Resveratrol treatment did not affect trabecular bone volume and bone remodeling indices in the youth animal model. Resveratrol supplementation in the early ageing rats tended to decrease trabecular bone volume, Sirt1 gene expression and increased expression of adipogenesis-related genes in bone, all of which were statistically insignificant. However, it decreased osteocalcin expression (p = 0.03). Furthermore, serum levels of bone resorption marker C-terminal telopeptides type I collagen (CTX-1) were significantly elevated in the resveratrol supplementation group (p = 0.02) with no changes observed in serum levels of bone formation marker alkaline phosphatase (ALP). These results in rat models suggest that resveratrol supplementation does not significantly affect bone volume

  9. Decoupled crystallization and eruption histories of the rhyolite magmatic system at Tarawera volcano revealed by zircon ages and growth rates

    NASA Astrophysics Data System (ADS)

    Storm, Sonja; Shane, Phil; Schmitt, Axel K.; Lindsay, Jan M.

    2012-03-01

    We obtained U-Th disequilibrium age data on zircons from each of the four rhyolite eruptions that built Tarawera volcano in the last 22 ka within the Okataina Volcanic Center (OVC), caldera, New Zealand. Secondary ion mass spectrometry analyses on unpolished euhedral crystal faces that lack resorption features show that crystal growth variously terminated from near-eruption age to ~100 ka prior to eruption. Age-depth profiling of crystals reveals long periods of continuous (~34 ka) and discontinuous growth (~90 ka). Growth hiatuses of up to ~40 ka duration occur, but do not all relate to obvious resorption surfaces. Age differences up to similar magnitude are found on opposing faces of some crystals suggesting episodes of partial exposure to melts. These features are best explained by periodic, complete, or partial, sub-solidus storage and/or inclusion in larger crystal phases, followed by rapid liberation prior to eruption. This is supported by high abundances of U and Th (~500 - >2,000 ppm) in some zircons consistent with periods of high crystallinity (>70%) in the magmatic system, based on crystal/melt partitioning. Contemporaneous but contrasting rim-ward trends of these elements within crystals, even in the same lava hand sample, require synchronous growth in separate melt bodies and little connectivity within the system, but also significant crystal transport and mixing prior to eruption. Many crystals record continuity of growth through the preceding ~60 ka OVC caldera-collapse and subsequent eruptions from Tarawera. This demonstrates a decoupling between eruption triggers, such as shallow crustal extension and mafic intrusion, and the crystallization state of the OVC silicic magmatic system. The data highlights the need to distinguish between the time for accumulation of eruptible magma and the long-term magma residence time based on the age of crystals with high closure temperatures, when assessing the potential for catastrophic eruptions.

  10. Growth and mortality of age-0 northern squawfish, Ptychocheilus oregonensis, rearing in shoreline habitats of the Columbia River Reservoir

    USGS Publications Warehouse

    Barfoot, C.A.; Gadomski, D.M.; Wertheimer, R.H.

    1999-01-01

    We investigated growth and mortality of age-0 northern squawfish during early rearing in shallow shoreline habitats. Larvae and juveniles (n=22914) were collected by weekly seining at three sample sites in the upper John Day Reservoir, Columbia River, during June through early September 1994–1996. Using a length-based ageing method, it was estimated that the exponential growth rate (G) for a common growth stanza (10–28 mm standard length SL) was significantly higher in 1994 (G=0.047) than in 1996 (G=0.037). Growth rate in 1995 could not be estimated, but was probably intermediate between 1994 and 1996 based on mean standard lengths of fish collected at the end of each sampling season (46.3, 40.0, and 32.0 mm SL in 1994, 1995, and 1996, respectively). For many fish species, variations in early growth can influence survival through size-selective mortality processes. Consistent with this possibility, our estimates of instantaneous mortality rates (Z) demonstrated that larvae and juveniles had significantly higher mortality in 1996 than in 1994 (Z=0.103 in 1994, versus Z=0.138 in 1996). Enhanced growth and lower mortality in 1994 were associated with a number of interrelated environmental conditions – comparatively low flows and turbidities, abundant instream vegetative cover, and high near-shore water temperatures.

  11. Age structure, carbonate production and shell loss rate in an Early Miocene reef of the giant oyster Crassostrea gryphoides

    NASA Astrophysics Data System (ADS)

    Harzhauser, M.; Djuricic, A.; Mandic, O.; Neubauer, T. A.; Zuschin, M.; Pfeifer, N.

    2015-09-01

    We present the first analysis of population structure and cohort distribution in a fossil oyster reef based on more than 1121 shells of the giant oyster Crassostrea gryphoides (Schlotheim, 1813). Data derive from Terrestrial Laser Scanning of a Lower Miocene shell bed covering 459 m2. Within two transects, individual shells were manually outlined on a digital surface model and cross-checked based on high-resolution orthophotos, resulting in accurate information on center line length and area of exposed shell surface. A growth model was calculated, revealing this species as the fastest growing and largest Crassostrea known so far. Non-normal distribution of size, area and age data hints at the presence of at least four distinct recruitment cohorts. The rapid decline of frequency amplitudes with age is interpreted to be a function of mortality and shell loss. The calculated shell half-lives range around few years, indicating that oyster reefs were geologically short-lived structures, which could have been fully degraded on a decadal scale. Crassostrea gryphoides reefs were widespread and common along the Miocene circum-Tethyan coasts. Given its enormous growth performance of ~ 150 g carbonate per year this species has been an important carbonate producer in estuarine settings. Yet, the rapid shell loss impeded the formation of stable structures comparable to coral reefs.

  12. Age structure, carbonate production and shell loss rate in an Early Miocene reef of the giant oyster Crassostrea gryphoides

    NASA Astrophysics Data System (ADS)

    Harzhauser, Mathias; Djuricic, Ana; Mandic, Oleg; Neubauer, Thomas A.; Zuschin, Martin; Pfeifer, Norbert

    2016-02-01

    We present the first analysis of population structure and cohort distribution in a fossil oyster shell bed based on 1121 shells of the giant oyster Crassostrea gryphoides (von Schlotheim, 1813). Data derive from terrestrial laser scanning of a Lower Miocene shell bed covering 459 m2. Within two transects, individual shells were manually outlined on a digital surface model and cross-checked based on high-resolution orthophotos, resulting in accurate information on center line length and area of exposed shell surface. A growth model was calculated, revealing this species as the fastest growing and largest Crassostrea known so far. Non-normal distribution of size, area and age data hints at the presence of at least four distinct recruitment cohorts. The rapid decline of frequency amplitudes with age is interpreted to be a function of mortality and shell loss. The calculated shell half-lives range around a few years, indicating that oyster reefs were geologically short-lived structures, which could have been fully degraded on a decadal scale. Crassostrea gryphoides reefs were widespread and common along the Miocene circum-Tethyan coasts. Given its enormous growth performance of ˜ 150 g carbonate per year this species has been an important carbonate producer in estuarine settings. Yet, the rapid shell loss impeded the formation of stable structures comparable to coral reefs.

  13. Direct measurement of riverine particulate organic carbon age structure

    NASA Astrophysics Data System (ADS)

    Rosenheim, Brad E.; Galy, Valier

    2012-10-01

    Carbon cycling studies focusing on transport and transformation of terrigenous carbon sources toward marine sedimentary sinks necessitate separation of particulate organic carbon (OC) derived from many different sources and integrated by river systems. Much progress has been made on isolating and characterizing young biologically-formed OC that is still chemically intact, however quantification and characterization of old, refractory rock-bound OC has remained troublesome. Quantification of both endmembers of riverine OC is important to constrain exchanges linking biologic and geologic carbon cycles and regulating atmospheric CO2 and O2. Here, we constrain petrogenic OC proportions in suspended sediment from the headwaters of the Ganges River in Nepal through direct measurement using ramped pyrolysis radiocarbon analysis. The unique results apportion the biospheric and petrogenic fractions of bulk particulate OC and characterize biospheric OC residence time. Compared to the same treatment of POC from the lower Mississippi-Atchafalaya River system, contrast in age spectra of the Ganges tributary samples illustrates the difference between small mountainous river systems and large integrative ones in terms of the global carbon cycle.

  14. Structure formation and the end of the cosmic dark ages

    NASA Astrophysics Data System (ADS)

    Alvarez, Marcelo Alonso

    We present results on the evolution of dark matter halos and reionization. Dark matter halos enshroud galaxies, quasars and stars. As such, they are fundamentally important to structure formation. In studying reionization, we focus on photoionization by the first stars, the 21-cm and cosmic microwave backgrounds, and its large-scale structure. Several new and important results are presented. First, we analyze the evolution of dark matter haloes that result from collapse within cosmological pancakes. Their mass accretion history and concentration are very similar to those reported simulations of CDM. Thus, fundamental properties of virialized halo formation and evolution are generic and not limited to hierarchical clustering or Gaussian-random-noise initial conditions. We also find that a simple one dimensional fluid model can explain this universal behaviour, implying that the evolving structure of CDM halos can be well understood as the effect of a universal, time-varying rate of smooth and continuous mass infall on an isotropic, collisionless fluid. We discuss cosmological reionization, from small scales and early times, to large scales and late times. We have simulated ionization fronts (I-fronts) created by the first stars forming in "minihalos". We find that nearby minihalos trap the I-front, so their centers remain neutral, contrary to the suggestion that these stars would trigger a second generation by ionizing neighboring minihalos cores. We then turn to the cross-correlation of cosmic microwave background (CMB) and 21-cm maps. We find that its measurement can be used to reconstruct the reionization history of the universe. Afterwards, we discuss the three versus first-year data from the Wilkinson Microwave Anisotropy Probe (WMAP). Surprisingly, the delay of reionization from three-year data is matched by a similar delay in structure formation. These effects cancel to leave the source halo efficiency constraints unchanged. We conclude by analyzing the

  15. The effect of exercise on bone mass and structural geometry during growth.

    PubMed

    Daly, Robin M

    2007-01-01

    activities that will optimize bone structure and strength during growth. Perhaps most importantly, further work is also needed to determine whether any exercise-induced alterations in bone mass and structure during growth are maintained into old age when fractures occur. PMID:17505118

  16. [Age and growth of the grunt, Haemulon steindachneri (Perciformis: Haemulidae), from the Southwest area of Margarita Island, Venezuela].

    PubMed

    Morales, Misael; González, Leo W

    2010-03-01

    Studies on fish age and growth are essential to establish models on population dynamics. We determined age and growth of the grunt Haemulon steindachneri from the Southwest Margarita Island using sagita otoliths (direct method) and length frequency (indirect method). A total of 953 individuals were captured by the handcrafted fleet from Boca del Rio (Margarita Island) between July 2005 and June 2006. The length-weight relation was established and growth parameters from both curves (length and weight) were estimated using the von Bertalanffy model. The analysis of the annual rings in otoliths established four age groups, and group 3+ was the most representative, with 44.5% of the sample. The calculation of marginal increases of otoliths suggested the development of an annual ring in April, which coincides with the maximum reproduction period. There were no significant differences in the slopes of the curves b (ts=-1.81; p>0.05) and the intercepts a (ts=-1.17; p>0.05) of females and males. Length-weight for both sexes was W=0.0003*L(2.89), which indicates an alometric growth pattern. Growth parameters were established as: Linfinity=231 mm, Winfinity=203 g, k=0.569 year(-1) (direct method) and Linfinity=228 mm, Winfinity=195 g, k=0.580 year(-1) (indirect method), which suggests that it is a short life species that grows moderately rapidly. The index of growth phi prime (Ø') coefficient of variation (CV), showed similarity between the growth parameters obtained by both (direct and indirect) methods. The application of the indirect method is recommended, as well as the periodic analysis of population parameters. PMID:20411724

  17. Modeling Elementary Aged Students' Fluency Growth in Written Expression: Predicting Fluency Growth for Girls and Boys in General Education

    ERIC Educational Resources Information Center

    Truckenmiller, Adrea J.

    2011-01-01

    Research on evidence-based writing intervention practices as well as reliable and valid assessments of elementary-aged students' writing fluency has been lacking compared to other academic areas (i.e., reading). Performance feedback interventions targeting writing fluency are gaining empirical support (Eckert et al., 2006); however, growth…

  18. Looking for age-related growth decline in natural forests: unexpected biomass patterns from tree rings and simulated mortality

    USGS Publications Warehouse

    Foster, Jane R.; D'Amato, Anthony W.; Bradford, John B.

    2014-01-01

    Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality models to address two questions: first, how do assumptions about tree growth and mortality influence reconstructions of biomass growth? Second, under what circumstances does biomass production follow the model that peaks early, then declines? We integrated three stochastic mortality models with a census tree-ring data set from eight temperate forest types to reconstruct stand-level biomass increments (in Minnesota, USA). We compared growth patterns among mortality models, forest types and stands. Timing of peak biomass growth varied significantly among mortality models, peaking 20–30 years earlier when mortality was random with respect to tree growth and size, than when mortality favored slow-growing individuals. Random or u-shaped mortality (highest in small or large trees) produced peak growth 25–30 % higher than the surviving tree sample alone. Growth trends for even-aged, monospecific Pinus banksiana or Acer saccharum forests were similar to the early peak and decline expectation. However, we observed continually increasing biomass growth in older, low-productivity forests of Quercus rubra, Fraxinus nigra, and Thuja occidentalis. Tree-ring reconstructions estimated annual changes in live biomass growth and identified more diverse development patterns than previous methods. These detailed, long-term patterns of biomass development are crucial for detecting recent growth responses to global change and modeling future forest dynamics.

  19. Current status of vascular endothelial growth factor inhibition in age-related macular degeneration.

    PubMed

    Mousa, Shaker A; Mousa, Shaymaa S

    2010-06-01

    Angiogenesis, the process by which new vessels are created from pre-existing vasculature, has become the subject of intense research in recent years. Increased rates of angiogenesis are associated with several disease states, including cancer, age-related macular degeneration (AMD), psoriasis, rheumatoid arthritis, and diabetic retinopathy. Vascular endothelial growth factor (VEGF) is an important modulator of angiogenesis, and has been implicated in the pathology of a number of conditions, including AMD, diabetic retinopathy, and cancer. AMD is a progressive disease of the macula and the third major cause of blindness worldwide. If not treated appropriately, AMD can progress to involve both eyes. Until recently, the treatment options for AMD have been limited, with photodynamic therapy (PDT) the mainstay of treatment. Although PDT is effective at slowing disease progression, it rarely results in improved vision. Several therapies have been or are now being developed for neovascular AMD, with the goal of inhibiting VEGF. These VEGF inhibitors include the RNA aptamer pegaptanib, partial and full-length antibodies ranibizumab and bevacizumab, the VEGF receptor decoy aflibercept, small interfering RNA-based therapies bevasiranib and AGN 211745, sirolimus, and tyrosine kinase inhibitors, including vatalanib, pazopanib, TG 100801, TG 101095, AG 013958, and AL 39324. At present, established therapies have met with great success in reducing the vision loss associated with neovascular AMD, whereas those still under investigation offer the potential for further advances. In AMD patients, these therapies slow the rate of vision loss and in some cases increase visual acuity. Although VEGF-inhibitor therapies are a milestone in the treatment of these disease states, several concerns need to be addressed before their impact can be fully realized. PMID:20210371

  20. The aging of elite male athletes: age-related changes in performance and skeletal muscle structure and function

    PubMed Central

    Faulkner, John A.; Davis, Carol S.; Mendias, Christopher L.; Brooks, Susan V.

    2009-01-01

    Objective The paper addresses the degree to which the attainment of the status as an elite athlete in different sports ameliorates the known age-related losses in skeletal muscle structure and function. Design The retrospective design, based on comparisons of published data on former elite and masters athletes and data on control subjects, assessed the degree to which the attainment of ‘elite and masters athlete status’ ameliorated the known age-related changes in skeletal muscle structure and function. Setting Institutional. Participants Elite male athletes. Interventions Participation in selected individual and team sports. Main Outcome Measurements Strength, power, VO2 max and performance. Results For elite athletes in all sports, as for the general population, age-related muscle atrophy begins at about 50 years of age. Despite the loss of muscle mass, elite athletes who maintain an active life style age gracefully with few health problems. Conversely, those who lapse into inactivity regress toward general population norms for fitness, weight control, and health problems. Elite athletes in the dual and team sports have careers that rarely extend into the thirties. Conclusions Life long physical activity does not appear to have any impact on the loss in fiber number. The loss of fibers can be buffered to some degree by hypertrophy of fibers that remain. Surprisingly, the performance of elite athletes in all sports appears to be impaired before the onset of the fiber loss. Even with major losses in physical capacity and muscle mass, the performance of elite and masters athletes is remarkable. PMID:19001883

  1. Trends in age and anthropometric data at start of growth hormone treatment for girls with Turner syndrome in Japan.

    PubMed

    Isojima, Tsuyoshi; Yokoya, Susumu; Ito, Junko; Horikawa, Reiko; Tanaka, Toshiaki

    2008-12-01

    The purpose of this study is to evaluate the trends in age and anthropometric data for girls with Turner syndrome (TS) at start of growth hormone (GH) treatment in Japan. The data for analysis were obtained from a retrospective cohort, the Foundation for Growth Science, Japan. We analyzed trends in starting age of GH treatment for girls with TS in Japan after dividing subjects (n=1,478) into three registration periods: 1991-1994, 1995-1999 and 2000-2004. We also assessed the ratio of the subpopulation of subjects under five years of age. As results, the mean age (standard deviation (SD)) at start of GH treatment was significantly different among the three groups (10.95 (3.63), 10.15 (3.39) and 8.78 (3.61), p<0.0001). The proportion of the subjects under five years of age increased significantly over time (5.11%, 7.11% and 16.85%, p<0.0001). Mean (SD) height SD scores were also significantly different (-3.41 (0.87), -3.26 (0.81) and -3.17 (0.79), p<0.0001). However, the proportions of the karyotype of 45,X were not significantly different among the three groups (p=0.25). We concluded that age and shortness at initiation of GH treatment had been improving over time. However, these favorable trends have not fully met the conditions recommended by international clinical guidelines for TS. PMID:18753703

  2. Temporal changes in carbohydrate digestive capacity and growth rate of piglets in response to glucocorticoid administration and weaning age.

    PubMed

    Chapple, R P; Cuaron, J A; Easter, R A

    1989-11-01

    Two experiments were conducted that demonstrated that a single injection of hydrocortisone 21-acetate (HYD, 25 mg/kg BW) administered to 6-d-old nursing piglets resulted in a twofold elevation (P less than .02) of pancreatic amylase within 2 d; activity was unaffected by an injection of 15 IU adrenocorticotropic hormone (ACTH)/kg BW (P greater than .20). Intestinal sucrase and maltase activity tended to be elevated (P less than .20) 2 and 4 d postinjection with HYD but returned to normal (uninjected) levels by 14 d of age. The normal decline of intestinal lactase activity was delayed by at least 4 d in response to both hormones (P less than .10). Organ weights were not affected by either hormone. In a separate experiment, postweaning mortality was reduced (12 vs 27%) and growth rate was substantially improved by administration of HYD to piglets 4 and 2 d prior to weaning at 14 d of age. Hydrocortisone resulted in a faster rate of gain the 1st wk postweaning for pigs weaned at 21 or 28 d. Subsequent gain by control and HYD piglets weaned on d 21 was similar, but HYD subsequently impaired growth rate of piglets weaned at 28 d of age. Growth rates of control and ACTH piglets were similar at each postweaning period regardless of weaning age (weaning age [lin.] x week postweaning [quad.] x treatment, P less than .07). This differential treatment response of daily gain may be due in part to effects on feed intake (weaning age [lin.] x week postweaning [lin.] x treatment, P less than .10). We conclude that a single injection of HYD to 6-d-old piglets precociously induces pancreatic amylase and that the sensitivity of piglets to HYD is age-dependent. PMID:2556357

  3. Pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF) in aged human choroid and eyes with age-related macular degeneration

    PubMed Central

    Bhutto, Imran A.; McLeod, D. Scott; Hasegawa, Takuya; Kim, Sahng Y.; Merges, Carol; Tong, Patrick; Lutty, Gerard A.

    2016-01-01

    The purpose of this study was to examine the localization and relative levels of vascular endothelial growth factor (VEGF; an angiogenic factor) and pigment epithelium-derived factor (PEDF; an antiangiogenic factor) in aged human choroid and to determine if the localization or their relative levels changed in age-related macular degeneration (AMD). Ocular tissues were obtained from eight aged control donors (age range, 75–86 years; mean age, 79.8 years) with no evidence or history of chorioretinal disease and from 12 donors diagnosed with AMD (age range, 61–105 years; mean age, 83.9 years). Tissues were cryopreserved and streptavidin alkaline phosphatase immunohistochemistry was performed with rabbit polyclonal anti-human VEGF and rabbit polyclonal anti-human PEDF antibodies. Binding of the antibodies was blocked by preincubation of the antibody with an excess of recombinant human PEDF or VEGF peptide. Choroidal blood vessels were identified with mouse anti-human CD-34 antibody in adjacent tissue sections. Three independent observers graded the immunohistochemical reaction product. The most prominent sites of VEGF and PEDF localization in aged control choroid were RPE–Bruch’s membrane–choriocapillaris complex including RPE basal lamina, intercapillary septa, and choroidal stroma. There was no significant difference in immunostaining intensity and localization of VEGF and PEDF in aged control choroids. The most intense VEGF immunoreactivity was observed in leukocytes within blood vessels. AMD choroid had a similar pattern and intensity of VEGF immunostaining to that observed in aged controls. However, PEDF immunoreactivity was significantly lower in RPE cells (p = 0.0073), RPE basal lamina (p = 0.0141), Bruch’s membrane (p < 0.0001), and choroidal stroma (p = 0.0161) of AMD choroids. The most intense PEDF immunoreactivity was observed in disciform scars. Drusen and basal laminar deposits (BLDs) were positive for VEGF and PEDF. In aged control subjects

  4. Some Effects of Sex, Age, and Household Structure on Family Drawings of Barbadian Children.

    ERIC Educational Resources Information Center

    Payne, Monica A.

    1996-01-01

    Reports on an analysis of the family drawings of a nonclinical sample of 502 Barbadian children ages 7-11. Reveals a correlation among sex, age, and household structure and the inclusion or omission of figures, as well as the size and positioning of the figures of parent and self. (MJP)

  5. Estimating survival rates with time series of standing age-structure data

    USGS Publications Warehouse

    Udevitz, Mark S.; Gogan, Peter J.

    2014-01-01

    It has long been recognized that age-structure data contain useful information for assessing the status and dynamics of wildlife populations. For example, age-specific survival rates can be estimated with just a single sample from the age distribution of a stable, stationary population. For a population that is not stable, age-specific survival rates can be estimated using techniques such as inverse methods that combine time series of age-structure data with other demographic data. However, estimation of survival rates using these methods typically requires numerical optimization, a relatively long time series of data, and smoothing or other constraints to provide useful estimates. We developed general models for possibly unstable populations that combine time series of age-structure data with other demographic data to provide explicit maximum likelihood estimators of age-specific survival rates with as few as two years of data. As an example, we applied these methods to estimate survival rates for female bison (Bison bison) in Yellowstone National Park, USA. This approach provides a simple tool for monitoring survival rates based on age-structure data.

  6. Aging Optimization of Aluminum-Lithium Alloy C458 for Application to Cryotank Structures

    NASA Technical Reports Server (NTRS)

    Sova, B. J.; Sankaran, K. K.; Babel, H. W.; Farahmand, B.; Rioja, R.

    2003-01-01

    This viewgraph report presents an examination of the fracture toughness of aluminum-lithium alloy C458 for use in cryotank structures. Topics cover include: cryogenics, alloy composition, strengthing precipitates in C458, cryogenic fracture toughness improvements, design of experiments for measuring aging optimization of C458 plate and effects of aging of properties of C458 plate.

  7. Factor Structure of Attention Deficit Hyperactivity Disorder Symptoms for Children Age 3 to 5 Years

    ERIC Educational Resources Information Center

    McGoey, Kara E.; Schreiber, James; Venesky, Lindsey; Westwood, Wendy; McGuirk, Lindsay; Schaffner, Kristen

    2015-01-01

    The diagnosis of attention deficit hyperactivity disorder (ADHD) distinguishes two dimensions of symptoms, inattention and hyperactivity-impulsivity for ages 3 to adulthood. Currently, no separate classification for preschool-age children exists, whereas preliminary research suggests that the two-factor structure of ADHD may not match the…

  8. Does white matter structure or hippocampal volume mediate associations between cortisol and cognitive ageing?

    PubMed Central

    Cox, Simon R.; MacPherson, Sarah E.; Ferguson, Karen J.; Royle, Natalie A.; Maniega, Susana Muñoz; Hernández, Maria del C. Valdés; Bastin, Mark E.; MacLullich, Alasdair M.J.; Wardlaw, Joanna M.; Deary, Ian J.

    2015-01-01

    Elevated glucocorticoid (GC) levels putatively damage specific brain regions, which in turn may accelerate cognitive ageing. However, many studies are cross-sectional or have relatively short follow-up periods, making it difficult to relate GCs directly to changes in cognitive ability with increasing age. Moreover, studies combining endocrine, MRI and cognitive variables are scarce, measurement methods vary considerably, and formal tests of the underlying causal hypothesis (cortisol → brain → cognition) are absent. In this study, 90 men, aged 73 years, provided measures of fluid intelligence, processing speed and memory, diurnal and reactive salivary cortisol and two measures of white matter (WM) structure (WM hyperintensity volume from structural MRI and mean diffusivity averaged across 12 major tracts from diffusion tensor MRI), hippocampal volume, and also cognitive ability at age 11. We tested whether negative relationships between cognitive ageing differences (over more than 60 years) and salivary cortisol were significantly mediated by WM and hippocampal volume. Significant associations between reactive cortisol at 73 and cognitive ageing differences between 11 and 73 (r = −.28 to −.36, p < .05) were partially mediated by both WM structural measures, but not hippocampal volume. Cortisol-WM relationships were modest, as was the degree to which WM structure attenuated cortisol–cognition associations (<15%). These data support the hypothesis that GCs contribute to cognitive ageing differences from childhood to the early 70s, partly via brain WM structure. PMID:26298692

  9. Comparison of otolith and scale readings for age and growth estimation of common dentex Dentex dentex.

    PubMed

    Baudouin, M; Marengo, M; Pere, A; Culioli, J-M; Santoni, M-C; Marchand, B; Durieux, E D H

    2016-02-01

    Three methods of age estimation were compared for Dentex dentex. Based on sectioned otoliths, scales appeared to be relevant only up to 5 years and whole otoliths up to 12 years. The maximum estimated age was 36 years, which constitutes to date the oldest age reported. PMID:26563912

  10. Is Old Age Depressing? Growth Trajectories and Cohort Variations in Late-Life Depression

    ERIC Educational Resources Information Center

    Yang, Yang

    2007-01-01

    Findings in previous research on the association of old age and depression are inconsistent due to a confounding of age changes and cohort differences. Using data from an accelerated longitudinal design from the National Institute of Aging Established Populations for Epidemiologic Studies of the Elderly, this study addresses three questions: (1)…

  11. Aging management of safety-related concrete structures in nuclear power plants

    SciTech Connect

    Naus, D.J.; Oland, C.B. ); Arndt, E.G. )

    1990-01-01

    The Structural Aging Program has the overall objective of providing the US Nuclear Regulatory Commission with an improved basis for evaluating nuclear power plants for continued service. In meeting this objective, a materials property data base is being developed as well as an aging assessment methodology for concrete structures in nuclear power plants. Furthermore, studies are well under way to review and assess inservice inspection techniques for concrete structures and to develop a methodology which can be used for performing current as well as reliability-based future conditions assessments of these structures. 16 refs., 2 tabs.

  12. Structural Aging Program to evaluate continued performance of safety-related concrete structures in nuclear power plants

    SciTech Connect

    Naus, D.J.; Oland, C.B.; Ellingwood, B.R.

    1994-03-01

    This report discusses the Structural Aging (SAG) Program which is being conducted at the Oak Ridge National Laboratory (ORNL) for the United States Nuclear Regulatory commission (USNRC). The SAG Program is addressing the aging management of safety-related concrete structures in nuclear power plants for the purpose of providing improved technical bases for their continued service. The program is organized into three technical tasks: Materials Property Data Base, Structural Component Assessment/Repair Technologies, and Quantitative Methodology for continued Service Determinations. Objectives and a summary of recent accomplishments under each of these tasks are presented.

  13. 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. PMID:27001144

  14. Growth, defect structure, and THz application of stoichiometric lithium niobate

    NASA Astrophysics Data System (ADS)

    Lengyel, K.; Péter, Á.; Kovács, L.; Corradi, G.; Pálfalvi, L.; Hebling, J.; Unferdorben, M.; Dravecz, G.; Hajdara, I.; Szaller, Zs.; Polgár, K.

    2015-12-01

    Owing to the extraordinary richness of its physical properties, congruent lithium niobate has attracted multidecade-long interest both for fundamental science and applications. The combination of ferro-, pyro-, and piezoelectric properties with large electro-optic, acousto-optic, and photoelastic coefficients as well as the strong photorefractive and photovoltaic effects offers a great potential for applications in modern optics. To provide powerful optical components in high energy laser applications, tailoring of key material parameters, especially stoichiometry, is required. This paper reviews the state of the art of growing large stoichiometric LiNbO3 (sLN) crystals, in particular, the defect engineering of pure and doped sLN with emphasis on optical damage resistant (ODR) dopants (e.g., Mg, Zn, In, Sc, Hf, Zr, Sn). The discussion is focused on crystals grown by the high temperature top seeded solution growth (HTTSSG) technique using alkali oxide fluxing agents. Based on high-temperature phase equilibria studies of the Li2O-Nb2O5-X2O ternary systems (X = Na, K, Rb, Cs), the impact of alkali homologue additives on the stoichiometry of the lithium niobate phase will be analyzed, together with a summary of the ultraviolet, infrared, and far-infrared absorption spectroscopic methods developed to characterize the composition of the crystals. It will be shown that using HTTSSG from K2O containing flux, crystals closest to the stoichiometric composition can be grown characterized by a UV-edge position of at about 302 nm and a single narrow hydroxyl band in the IR with a linewidth of less than 3 cm-1 at 300 K. The threshold concentrations for ODR dopants depend on crystal stoichiometry and the valence of the dopants; Raman spectra, hydroxyl vibration spectra, and Z-scan measurements prove to be useful to distinguish crystals below and above the photorefractive threshold. Crystals just above the threshold are preferred for most nonlinear optical applications apart

  15. Longitudinal study of growth of children with unilateral cleft-lip palate from birth to two years of age

    PubMed Central

    Marques, Ilza L.; Nackashi, John A.; Borgo, Hilton C.; Martinelli, Ângela P. M. C.; Pegoraro-Krook, Maria I.; Williams, William N.; Dutka, Jeniffer C. R.; Seagle, Michael B.; Souza, Telma V.; Garla, Luis A.; Neto, José S. M.; Silva, Marcos L. N.; Graciano, Maria I. G.; Moorhead, Jacquelyn; A Piazentin-Penna, Sílvia H.; Feniman, Mariza R.; Zimmermann, Maria C.; Bento-Gonçalves, Cristina G. A.; Pimentel, Maria C. M.; Boggs, Steve; Jorge, José C.; Antonelli, Patrick J.; Shuster, Jonathan

    2009-01-01

    Objective To study the growth of children with complete unilateral cleft lip and palate (UCLP) from birth to 2 years of age and to construct specific UCLP growth curves. Design Physical growth was a secondary outcome measure of a NIH sponsored longitudinal, prospective clinical trial involving the University of Florida (USA) and the University of São Paulo (Brazil). Patients 627 children with UCLP, nonsyndromic, both genders. Methods Length, weight, and head circumference were prospectively measured for a group of children enrolled in a clinical trial. Median growth curves for the 3 parameters (length, weight, head circumference) were performed and compared to the median for the National Center for Health Statistics (NCHS, 2000) curves. The median values for length, weight, and head circumference at birth, 6, 12, 18 and 24 month of age were plotted against NCHS median values, and statistically compared at birth and 24 months. Setting Hospital de Reabilitação de Anomalias Craniofaciais, Universidade de São Paulo, Bauru, Brazil (HRAC-USP). Results At birth, children of both genders with UCLP presented with smaller body dimensions in relation to NCHS median values, but the results suggest a “catch up growth” for length, weight, and head circumference for girls and for weight (to some degree) and head circumference for boys. Conclusions Weight was the most compromised parameter for both genders followed by length and then head circumference. There was no evidence of short statue. This study established growth curves for children with UCLP. PMID:19860503

  16. The hepatic transcriptome of young suckling and aging intrauterine growth restricted male rats.

    PubMed

    Freije, William A; Thamotharan, Shanthie; Lee, Regina; Shin, Bo-Chul; Devaskar, Sherin U

    2015-04-01

    Intrauterine growth restriction leads to the development of adult onset obesity/metabolic syndrome, diabetes mellitus, cardiovascular disease, hypertension, stroke, dyslipidemia, and non-alcoholic fatty liver disease/steatohepatitis. Continued postnatal growth restriction has been shown to ameliorate many of these sequelae. To further our understanding of the mechanism of how intrauterine and early postnatal growth affects adult health we have employed Affymetrix microarray-based expression profiling to characterize hepatic gene expression of male offspring in a rat model of maternal nutrient restriction in early and late life. At day 21 of life (p21) combined intrauterine and postnatal calorie restriction treatment led to expression changes in circadian, metabolic, and insulin-like growth factor genes as part of a larger transcriptional response that encompasses 144 genes. Independent and controlled experiments at p21 confirm the early life circadian, metabolic, and growth factor perturbations. In contrast to the p21 transcriptional response, at day 450 of life (d450) only seven genes, largely uncharacterized, were differentially expressed. This lack of a transcriptional response identifies non-transcriptional mechanisms mediating the adult sequelae of intrauterine growth restriction. Independent experiments at d450 identify a circadian defect as well as validate expression changes to four of the genes identified by the microarray screen which have a novel association with growth restriction. Emerging from this rich dataset is a portrait of how the liver responds to growth restriction through circadian dysregulation, energy/substrate management, and growth factor modulation. PMID:25371150

  17. An agent-based computational model for tuberculosis spreading on age-structured populations

    NASA Astrophysics Data System (ADS)

    Graciani Rodrigues, C. C.; Espíndola, Aquino L.; Penna, T. J. P.

    2015-06-01

    In this work we present an agent-based computational model to study the spreading of the tuberculosis (TB) disease on age-structured populations. The model proposed is a merge of two previous models: an agent-based computational model for the spreading of tuberculosis and a bit-string model for biological aging. The combination of TB with the population aging, reproduces the coexistence of health states, as seen in real populations. In addition, the universal exponential behavior of mortalities curves is still preserved. Finally, the population distribution as function of age shows the prevalence of TB mostly in elders, for high efficacy treatments.

  18. Age, Growth and Feeding Habits of the Brown Comber Serranus hepatus(Linnaeus, 1758) on the Cretan Shelf

    NASA Astrophysics Data System (ADS)

    Labropoulou, M.; Tserpes, G.; Tsimenides, N.

    1998-05-01

    Forty-five samples of the brown comber Serranus hepatuswere collected during experimental surveys carried out on a monthly basis (August 1990 to August 1992) along the Cretan continental shelf. A total of 1268 specimens 31-140 mm in total length were analysed. Growth was well described by both standard and seasonalized forms of the von Bertalanffy growth model and the computed parameters were L∞;=152 mm, k=0·36, t0=-0·57. Feeding intensity was high throughout the study period and varied significantly among the age classes of fish examined. Stomach content analysis revealed that S. hepatusis carnivorous, feeding mainly on decapods. Diets did not vary seasonally; decapods were the most important prey throughout the year. However, the composition of the prey consumed varied considerably with predator age coupled with differences in mean prey sizes utilized by each age class. The mean weight of stomach contents increased significantly for older specimens, while the mean number of prey items decreased. Age-specific dietary selection was primarily a function of body size of the predator and appears to reduce intra-specific competition among the members of the different age classes. The results suggest that S. hepatusplays an important trophic role as a macrophagic carnivorous species on the Cretan continental shelf.

  19. A cross-sectional study of the growth characteristics of Nigerian infants from birth to 2 years of age.

    PubMed

    VanderJagt, D J; Waymire, L; Obadofin, M O; Marjon, N; Glew, R H

    2009-12-01

    Malnutrition compromises the growth of children in sub-Saharan Africa. In Nigeria, the prevalence of childhood malnutrition approaches 40%. There are few reports relating the growth characteristics of breast-fed Nigerian infants to the anthropometric properties of their mothers. A total of 100 urban and rural mother/baby pairs were recruited. The mean BMI values of the urban and rural mothers were 24.2 and 21.3 kg m(-2), respectively. The mean length, weight and head circumference of the rural infants were significantly lower than those of the urban infants. Z-scores based on World Health Organization standards showed: (i) length-for-age z-score <-2 in urban (27%) and rural (33%) children; (ii) a higher incidence of underweight and small HC in rural (33%; and 13%) versus urban children (12% and 0%); and (iii) positive correlations between all three z-scores and maternal BMI. Negative correlations were observed between infant age and z-scores for length-for-age, weight-for-age and HC-for-age. PMID:19372149

  20. Mathematical Model of Three Age-Structured Transmission Dynamics of Chikungunya Virus

    PubMed Central

    Agusto, Folashade B.; Easley, Shamise; Freeman, Kenneth; Thomas, Madison

    2016-01-01

    We developed a new age-structured deterministic model for the transmission dynamics of chikungunya virus. The model is analyzed to gain insights into the qualitative features of its associated equilibria. Some of the theoretical and epidemiological findings indicate that the stable disease-free equilibrium is globally asymptotically stable when the associated reproduction number is less than unity. Furthermore, the model undergoes, in the presence of disease induced mortality, the phenomenon of backward bifurcation, where the stable disease-free equilibrium of the model coexists with a stable endemic equilibrium when the associated reproduction number is less than unity. Further analysis of the model indicates that the qualitative dynamics of the model are not altered by the inclusion of age structure. This is further emphasized by the sensitivity analysis results, which shows that the dominant parameters of the model are not altered by the inclusion of age structure. However, the numerical simulations show the flaw of the exclusion of age in the transmission dynamics of chikungunya with regard to control implementations. The exclusion of age structure fails to show the age distribution needed for an effective age based control strategy, leading to a one size fits all blanket control for the entire population. PMID:27190548

  1. Neuroanatomical correlates of cognitive aging: evidence from structural magnetic resonance imaging.

    PubMed

    Raz, N; Gunning-Dixon, F M; Head, D; Dupuis, J H; Acker, J D

    1998-01-01

    To examine putative brain substrates of cognitive functions differentially affected by age the authors measured the volume of cortical regions and performance on tests of executive functions, working memory, explicit memory, and priming in healthy adults (18-77 years old). The results indicate that shrinkage of the prefrontal cortex mediates age-related increases in perseveration. The volume of visual processing areas predicted performance on nonverbal working memory tasks. Contrary to the hypotheses, in the examined age range, the volume of limbic structures was unrelated to any of the cognitive functions; verbal working memory, verbal explicit memory, and verbal priming were independent of cortical volumes. Nevertheless, among the participants aged above 60, reduction in the volume of limbic structures predicted declines in explicit memory. Chronological age adversely influenced all cognitive indices, although its effects on priming were only indirect, mediated by declines in verbal working memory. PMID:9460738

  2. Age, Growth and Reproduction of the Eastern Mudminnow (Umbra pygmaea) at the Great Swamp National Wildlife Refuge, New Jersey.

    USGS Publications Warehouse

    Panek, Frank; Weis, Judith S.

    2012-01-01

    Umbra pygmaea DeKay (Eastern Mudminnow) is one of four species of Umbridae in North America. There is little published life-history information on the species within its native range, particularly on age, growth, and reproduction. This study focuses on these aspects of the life history of this fish at the Great Swamp National Wildlife Refuge in Morris County, NJ. A total of 336 fish of seven species was collected from June 1978 through May 1979, with the Eastern Mudminnow comprising 74% of the total. The average annual growth increment in total length for the Eastern Mudminnow was 15.3 2.06 mm, with age-1 fish averaging 40 mm total length and age-5 fish, the oldest collected, averaging 107 mm total length. The length-weight relationship was log10W = -5.291 + 3.182 log10TL mm for males and log10W = -4.999 + 3.032 log10TL mm for females. We observed no statistically significant sexually dimorphic differences in length-weight relationships in this population. The ratio of females to males increased from a low of 0.6 (predominance of male fish) at age-1 to a high of 4.6 (predominance of females) at age-5. Annual mortality for age 2–5 fish ranged from 40–76% with a mean of 59 13%. Age-specific fecundity estimates ranged from 250 eggs/female at age-1 to 2168 eggs/female at age-5. The relationship of number of mature ova to age was best described by the exponential function y = 149.29e0.5287x, where y = age-specific fecundity and x = age in years. Ova ranged from 0.1–0.2 mm in diameter in June and July and averaged 1.41 0.1 mm (range = 1.29–1.62 mm) in early February prior to spawning. Peak spawning occurred in mid-April at temperatures of 9–12 °C, and all females were spent by late April (13–15 °C).

  3. Growth

    NASA Astrophysics Data System (ADS)

    Waag, Andreas

    This chapter is devoted to the growth of ZnO. It starts with various techniques to grow bulk samples and presents in some detail the growth of epitaxial layers by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and pulsed laser deposition (PLD). The last section is devoted to the growth of nanorods. Some properties of the resulting samples are also presented. If a comparison between GaN and ZnO is made, very often the huge variety of different growth techniques available to fabricate ZnO is said to be an advantage of this material system. Indeed, growth techniques range from low cost wet chemical growth at almost room temperature to high quality MOCVD growth at temperatures above 1, 000∘C. In most cases, there is a very strong tendency of c-axis oriented growth, with a much higher growth rate in c-direction as compared to other crystal directions. This often leads to columnar structures, even at relatively low temperatures. However, it is, in general, not straight forward to fabricate smooth ZnO thin films with flat surfaces. Another advantage of a potential ZnO technology is said to be the possibility to grow thin films homoepitaxially on ZnO substrates. ZnO substrates are mostly fabricated by vapor phase transport (VPT) or hydrothermal growth. These techniques are enabling high volume manufacturing at reasonable cost, at least in principle. The availability of homoepitaxial substrates should be beneficial to the development of ZnO technology and devices and is in contrast to the situation of GaN. However, even though a number of companies are developing ZnO substrates, only recently good quality substrates have been demonstrated. However, these substrates are not yet widely available. Still, the situation concerning ZnO substrates seems to be far from low-cost, high-volume production. The fabrication of dense, single crystal thin films is, in general, surprisingly difficult, even when ZnO is grown on a ZnO substrate. However

  4. Mercury Exposure in Healthy Korean Weaning-Age Infants: Association with Growth, Feeding and Fish Intake

    PubMed Central

    Chang, Ju Young; Park, Jeong Su; Shin, Sue; Yang, Hye Ran; Moon, Jin Soo; Ko, Jae Sung

    2015-01-01

    Low-level mercury (Hg) exposure in infancy might be harmful to the physical growth as well as neurodevelopment of children. The aim of this study was to investigate postnatal Hg exposure and its relationship with anthropometry and dietary factors in late infancy. We recruited 252 healthy Korean infants between six and 24 months of age from an outpatient clinic during the 2009/2010 and 2013/2014 seasons. We measured the weight and height of the infants and collected dietary information using questionnaires. The Hg content of the hair and blood was assessed using inductively coupled plasma mass spectroscopy. The geometric mean Hg concentration in the hair and blood was 0.22 (95% confidence interval: 0.20–0.24) µg/g and 0.94 (n = 109, 95% confidence interval: 0.89–0.99) µg/L, respectively. The hair Hg concentration showed a good correlation with the blood Hg concentration (median hair-to-blood Hg ratio: 202.7, r = 0.462, p < 0.001) and was >1 µg/g in five infants. The hair Hg concentration showed significant correlations with weight gain after birth (Z-score of the weight for age—Z-score of the birthweight; r = −0.156, p = 0.015), the duration (months) of breastfeeding as the dominant method of feeding (r = 0.274, p < 0.001), and the duration of fish intake more than once per week (r = 0.138, p = 0.033). In an ordinal logistic regression analysis with categorical hair Hg content (quartiles), dietary factors, including breastfeeding as the dominant method of feeding in late infancy (cumulative odds ratio: 6.235, 95% confidence interval: 3.086–12.597, p < 0.001) and the monthly duration of fish intake more than once per week (cumulative odds ratio: 1.203, 95% confidence interval: 1.034–1.401; p = 0.017), were significantly associated with higher hair Hg content. Weight gain after birth was not, however, significantly associated with hair Hg content after adjustment for the duration of breastfeeding as the dominant method of feeding. Low-level Hg exposure

  5. Relationships between growth, population structure and sea surface temperature in the temperate solitary coral Balanophyllia europaea (Scleractinia, Dendrophylliidae)

    NASA Astrophysics Data System (ADS)

    Goffredo, S.; Caroselli, E.; Mattioli, G.; Pignotti, E.; Zaccanti, F.

    2008-09-01

    The demographic characteristics of the solitary zooxanthellate scleractinian Balanophyllia europaea, endemic to the Mediterranean, were determined in six populations, on a latitudinal gradient along the Italian coast, and compared with the mean annual sea surface temperature (SST). Growth rate correlated negatively, and asymptotic length of the individuals positively with SST. With increasing SST, the distributions of age frequencies moved away from a typical steady state structure (i.e., exponential decrease in the frequency of individuals with age), indicating less stable populations and showed a deficiency of individuals in the younger-age classes. These observations suggest that high temperatures are an adverse factor to the B. europaea symbiosis. Using projected increases in seawater temperature, most of the B. europaea populations in the Mediterranean are expected to be close to their thermal limits by 2100 and the populations at that time may support few young individuals.

  6. Quota implementation of the maximum sustainable yield for age-structured fisheries.

    PubMed

    Kanik, Zafer; Kucuksenel, Serkan

    2016-06-01

    One of the main goals stated in the proposals for the Common Fisheries Policy (CFP) reform was achieving maximum sustainable yield (MSY) for all European fisheries. In this paper, we propose a fishing rights allocation mechanism or management system, which specifies catch limits for individual fishing fleets to implement MSY harvesting conditions in an age-structured bioeconomic model. An age-structured model in a single species fishery with two fleets having perfect or imperfect fishing selectivity is studied. If fishing technology or gear selectivity depends on the relative age composition of the mature fish stock, fixed harvest proportions, derived from catchability and bycatch coefficients, is not valid anymore. As a result, not only the age-structure and fishing technology but also the estimated level of MSY is steering the allocation of quota shares. The results also show that allocation of quota shares based on historical catches or auctioning may not provide viable solutions to achieve MSY. PMID:27018447

  7. Heparin localization and fine structure regulate Burkitt's lymphoma growth

    SciTech Connect

    Berry, David; Lynn, David M.; Berry, Eric; Sasisekharan, Ram; Langer, Robert . E-mail: rlanger@mit.edu

    2006-09-29

    Burkitt's lymphoma (BL) is a B-cell malignancy associated with the Epstein-Barr virus (EBV). Mounting evidence has implicated heparan sulfate proteoglycans and heparan sulfate-like glycosaminoglycans (HSGAGs) in the initiation, severity, and progression of the malignancy. The importance of HSGAGs in regulating BL cell growth was therefore examined. Extracellular exogenous heparin inhibited cell growth >30%, while heparin internalized with poly({beta}-amino ester)s promoted proliferation up to 58%. The growth-modulating effects of heparin and internalized heparin were dependent on cell surface HSGAGs, PI3K, and Erk/Mek. Treatment of cells with protamine sulfate or with heparinases potently inhibited proliferation, with the greatest effects induced by heparinase I. Cell surface HSGAGs therefore play an important role in regulating BL proliferation and may offer a potential target for therapeutic intervention.

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

    USGS Publications Warehouse

    Coggins, L.G., Jr.; Pine, William E., III; 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.

  9. Spatial and temporal variations in the age structure of Arctic sea ice

    USGS Publications Warehouse

    Belchansky, G.I.; Douglas, D.C.; Platonov, N.G.

    2005-01-01

    Spatial and temporal variations in the age structure of Arctic sea ice are investigated using a new reverse chronology algorithm that tracks ice-covered pixels to their location and date of origin based on ice motion and concentration data. The Beaufort Gyre tends to harbor the oldest (>10 years old) sea ice in the western Arctic while direct ice advection pathways toward the Transpolar Drift Stream maintain relatively young (10 years old (10+ year age class) were observed during 1989-2003. Since the mid-1990s, losses to the 10+ year age class lacked compensation by recruitment due to a prior depletion of all mature (6-10 year) age classes. Survival of the 1994 and 1996-1998 sea ice generations reestablished most mature age classes, and thereby the potential to increase extent of the 10+ year age class during the mid-2000s.

  10. Protection of rubbers against aging with the use of structural, diffusion and kinetic effects

    SciTech Connect

    Kablov, V. F.; Zaikov, G. E.

    2014-05-15

    Processes of rubber aging in the different kinetic modes and mathematical models of the processes including aging and destruction processes under extreme conditions have been studied. The aging process for rubbers as thermodynamically open nonlinear systems has also been considered in the paper. It has been revealed that the aging process can be controlled by the internal physical-chemical processes organization and by creation of external influences (by organization of thermodynamic forces and flows). According to the Onsager principle, in certain conditions of aging the conjugation of thermodynamic forces and flows is possible. The diffusion and structural aspects of aging in elastomeric rubbers and articles thereof have been considered. The composite antiaging systems of prolonged action based on the use of microparticles with a saturated solution of the antiagers migrating into an elastomeric matrix at the exploitation have been proposed.

  11. Protection of rubbers against aging with the use of structural, diffusion and kinetic effects

    NASA Astrophysics Data System (ADS)

    Kablov, V. F.; Zaikov, G. E.

    2014-05-01

    Processes of rubber aging in the different kinetic modes and mathematical models of the processes including aging and destruction processes under extreme conditions have been studied. The aging process for rubbers as thermodynamically open nonlinear systems has also been considered in the paper. It has been revealed that the aging process can be controlled by the internal physical-chemical processes organization and by creation of external influences (by organization of thermodynamic forces and flows). According to the Onsager principle, in certain conditions of aging the conjugation of thermodynamic forces and flows is possible. The diffusion and structural aspects of aging in elastomeric rubbers and articles thereof have been considered. The composite antiaging systems of prolonged action based on the use of microparticles with a saturated solution of the antiagers migrating into an elastomeric matrix at the exploitation have been proposed.

  12. Coenzyme Q10 prevents accelerated cardiac aging in a rat model of poor maternal nutrition and accelerated postnatal growth.

    PubMed

    Tarry-Adkins, Jane L; Blackmore, Heather L; Martin-Gronert, Malgorzata S; Fernandez-Twinn, Denise S; McConnell, Josie M; Hargreaves, Iain P; Giussani, Dino A; Ozanne, Susan E

    2013-01-01

    Studies in human and animals have demonstrated that nutritionally induced low birth-weight followed by rapid postnatal growth increases the risk of metabolic syndrome and cardiovascular disease. Although the mechanisms underlying such nutritional programming are not clearly defined, increased oxidative-stress leading to accelerated cellular aging has been proposed to play an important role. Using an established rodent model of low birth-weight and catch-up growth, we show here that post-weaning dietary supplementation with coenzyme Q10, a key component of the electron transport chain and a potent antioxidant rescued many of the detrimental effects of nutritional programming on cardiac aging. This included a reduction in nitrosative and oxidative-stress, telomere shortening, DNA damage, cellular senescence and apoptosis. These findings demonstrate the potential for postnatal antioxidant intervention to reverse deleterious phenotypes of developmental programming and therefore provide insight into a potential translatable therapy to prevent cardiovascular disease in at risk humans. PMID:24327963

  13. Growth, age at metamorphosis, and sex ratio of northern brook lamprey in a tributary of southern Lake Superior

    USGS Publications Warehouse

    Purvis, Harold A.

    1970-01-01

    Growth was studied of five year classes of the northern brook lamprey, Ichthyomyzon fossor, collected from the Sturgeon River during intervals between treatment of the stream with a lampricide. Growth varied considerably among year classes. Larvae of the 1963 year class were slightly longer at age II and 30% longer at age III than the III-group larvae of the 1960 year class. About 6% of 558 III-group lampreys of the 1963 year class had metamorphosed by 17 August 1966. Although the sex ratio of larvae was about 1:1, 97% of the metamorphosed lampreys were males. The distribution of pigmentation on the caudal fin and upper lip in ammocoetes less than 40 mm long permitted accurate and rapid separation of northern brook lampreys from the sea lamprey, Petromyzon marinus.

  14. Structural Validity of the Professional Development Profile of the LoTi Digital-Age Survey

    ERIC Educational Resources Information Center

    Mehta, Vandhana; Hull, Darrell M.

    2013-01-01

    The present study was used to examine the structural construct validity of the Professional Development Profile of the LoTi Digital-Age Survey, a measure of teacher instructional practices with technology in the classroom. Teacher responses ("N" = 2,840) from across the United States were used to assess factor structure of the instrument using…

  15. Infants born large-for-gestational-age display slower growth in early infancy, but no epigenetic changes at birth

    PubMed Central

    Chiavaroli, Valentina; Cutfield, Wayne S.; Derraik, José G. B.; Pan, Zengxiang; Ngo, Sherry; Sheppard, Allan; Craigie, Susan; Stone, Peter; Sadler, Lynn; Ahlsson, Fredrik

    2015-01-01

    We evaluated the growth patterns of infants born large-for-gestational-age (LGA) from birth to age 1 year compared to those born appropriate-for-gestational-age (AGA). In addition, we investigated possible epigenetic changes associated with being born LGA. Seventy-one newborns were classified by birth weight as AGA (10th–90th percentile; n = 42) or LGA (>90th percentile; n = 29). Post-natal follow-up until age 1 year was performed with clinical assessments at 3, 6, and 12 months. Genome-wide DNA methylation was analysed on umbilical tissue in 19 AGA and 27 LGA infants. At birth, LGA infants had greater weight (p < 0.0001), length (p < 0.0001), ponderal index (p = 0.020), as well as greater head (p < 0.0001), chest (p = 0.044), and abdominal (p = 0.007) circumferences than AGA newborns. LGA infants were still larger at the age of 3 months, but by age 6 months there were no more differences between groups, due to higher length and weight increments in AGA infants between 0 and 6 months (p < 0.0001 and p = 0.002, respectively). Genome-wide analysis showed no epigenetic differences between LGA and AGA infants. Overall, LGA infants had slower growth in early infancy, being anthropometrically similar to AGA infants by 6 months of age. In addition, differences between AGA and LGA newborns were not associated with epigenetic changes. PMID:26419812

  16. Effects of nerve growth factor and heart cell conditioned medium on neurite regeneration of aged sympathetic neurons in culture.

    PubMed

    Uchida, Y; Tomonaga, M

    1985-11-25

    The effects of nerve growth factor (NGF) and heart-cell-conditioned medium (HCM) on the neurite regeneration of aged sympathetic neurons were investigated in culture. Investigation of HCM was carried out by two different methods: one was the use of whole HCM on collagen substratum, which reflected component(s) effective in solution (HCM-S); the other was the use of polyornithine (PORN)-binding component(s) (P-HCM). Superior cervical ganglion neurons prepared from male mice from 6 to 30 months of age were cultured in MEM-10% FCS on collagen or gelatin-PORN substratum for 3 days. The number of neurons with neurites and the length of neurites were quantified as neurite production and elongation, respectively. Neuronal survival was not affected by addition of NGF, HCM-S or P-HCM. Neurite production of early adult neurons was enhanced by NGF, HCM-S or P-HCM. In contrast, neurite production of aged neurons was enhanced by only HCM-S, but not NGF or P-HCM. HCM-S did not promote neurite elongation in neurons at any age. Neurite elongation of early adult neurons was enhanced by NGF or P-HCM. Neurite elongation of aged neurons was enhanced by P-HCM. However, responsiveness of NGF for neurite elongation varied according to substrata. No age-related difference was found in neurite production and elongation in the absence of NGF, HCM-S or P-HCM. These results indicate that responsiveness of aged sympathetic neurons is various in different growth factors. PMID:3840716

  17. Anti-vascular endothelial growth factor for neovascular age-related macular degeneration

    PubMed Central

    Solomon, Sharon D.; Lindsley, Kristina; Vedula, Satyanarayana S.; Krzystolik, Magdalena G.; Hawkins, Barbara S.

    2014-01-01

    Background Age-related macular degeneration (AMD) is the most common cause of uncorrectable severe vision loss in people aged 55 years and older in the developed world. Choroidal neovascularization (CNV) secondary to neovascular AMD accounts for most AMD-related severe vision loss. Anti-vascular endothelial growth factor (anti-VEGF) agents, injected intravitreally, aim to block the growth of abnormal blood vessels in the eye to prevent vision loss and, in some instances, improve vision. Objectives To investigate: (1) the ocular and systemic effects of, and quality of life associated with, intravitreally injected anti-VEGF agents (pegaptanib, ranibizumab, and bevacizumab) for the treatment of neovascular AMD compared with no anti-VEGF treatment; and (2) the relative effects of one anti-VEGF agent compared with another when administered in comparable dosages and regimens. Search methods We searched Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 3), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to March 2014), EMBASE (January 1980 to March 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to March 2014), the metaRegister of Controlled Trials (mRCT) (www.controlledtrials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We used no date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 27 March 2014. Selection criteria We included randomized controlled trials (RCTs) that evaluated pegaptanib, ranibizumab, or bevacizumab versus each other or a control treatment (e.g., sham treatment or photodynamic therapy). All trials followed participants for at least one year. Data collection

  18. Structural Validity of the Movement ABC-2 Test: Factor Structure Comparisons across Three Age Groups

    ERIC Educational Resources Information Center

    Schulz, Joerg; Henderson, Sheila E.; Sugden, David A.; Barnett, Anna L.

    2011-01-01

    Background: The Movement ABC test is one of the most widely used assessments in the field of Developmental Coordination Disorder (DCD). Improvements to the 2nd edition of the test (M-ABC-2) include an extension of the age range and reduction in the number of age bands as well as revision of tasks. The total test score provides a measure of motor…

  19. The effect of aging temperature on structure characteristics of ordered mesoporous silicas

    NASA Astrophysics Data System (ADS)

    Deryło-Marczewska, A.; Marczewski, A. W.; Skrzypek, I.; Pikus, S.; Kozak, M.

    2005-10-01

    A series of mesoporous silica materials were synthesized by applying Pluronic type polymers as pore creating agents. In order to differentiate the characteristics of porous structure of the obtained sorbents the temperature of aging process was changed in the synthesis. The parameters characterizing the pore structure were estimated from nitrogen adsorption/desorption isotherms. The changes of pore arrangement of the obtained materials being a result of different synthesis conditions were investigated by using a small angle X-ray scattering method. Correlations between the values of structure parameters and aging temperature were found.

  20. Age-class structure and variability of two populations of the bluemask darter etheostoma (Doration) sp.

    USGS Publications Warehouse

    Simmons, J.W.; Layzer, J.B.; Smith, D.D.

    2008-01-01

    The bluemask darter Etheostoma (Doration) sp. is an endangered fish endemic to the upper Caney Fork system in the Cumberland River drainage in central Tennessee. Darters (Etheostoma spp.) are typically short-lived and exhibit rapid growth that quickly decreases with age. Consequently, estimating age of darters from length-frequency distributions can be difficult and subjective. We used a nonparametric kernel density estimator to reduce subjectivity in estimating ages of bluemask darters. Data were collected from a total of 2926 bluemask darters from the Collins River throughout three growing seasons. Additionally, data were collected from 842 bluemask darters from the Rocky River during one growing season. Analysis of length-frequencies indicated the presence of four age classes in both rivers. In each river, the majority of the population was comprised of fish 0.05). In both rivers, females were more abundant than males.

  1. Topography and age mediate the growth responses of Smith fir to climate warming in the southeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Liu, B.; Wang, Y.; Zhu, H.; Liang, E.; Camarero, J. J.

    2016-03-01

    The Tibetan Plateau holds some of the world's highest undisturbed natural treelines and timberlines. Such extreme environments constitute potentially valuable monitoring sites of the effects of climate warming on high-elevation forests. Here, we analyze a network of 21 Smith fir forests situated in the Sygera Mountains, southeastern Tibetan Plateau, using tree-ring width (TRW) and basal area increment (BAI) chronologies. Sampled sites encompassed a wide elevation gradient, from 3600 to 4400 m, including some treeline sites and diverse aspects and tree ages. In comparison with TRW series, BAI series better capture the long-term warming signal. Previous November and current April and summer temperatures are the dominant climatic factors controlling Smith fir radial growth. The mean inter-series correlations of TRW increased upwards, but the forest limit presented the highest potential to reconstruct past temperature variability. Moreover, the growth responses of young trees were less stable than those of trees older than 100 years. Climate warming is accelerating radial growth of Smith fir forest subjected to mesic conditions. Collectively, these findings confirm that the effects of site elevation and tree age should be considered when quantifying climate-growth relationships. The type of tree-ring data (BAI vs. TRW) is also relevant since BAI indices seem to be a better climatic proxy of low-frequency temperature signals than TRW indices. Therefore, site (e.g., elevation) and tree (e.g., age) features should be considered to properly evaluate the effects of climate warming on growth of high-elevation forests.

  2. Growth, defect structure, and THz application of stoichiometric lithium niobate

    SciTech Connect

    Lengyel, K.; Péter, Á.; Kovács, L.; Corradi, G.; Dravecz, G.; Hajdara, I.; Szaller, Zs.; Polgár, K.; Pálfalvi, L.; Unferdorben, M.; Hebling, J.

    2015-12-15

    Owing to the extraordinary richness of its physical properties, congruent lithium niobate has attracted multidecade-long interest both for fundamental science and applications. The combination of ferro-, pyro-, and piezoelectric properties with large electro-optic, acousto-optic, and photoelastic coefficients as well as the strong photorefractive and photovoltaic effects offers a great potential for applications in modern optics. To provide powerful optical components in high energy laser applications, tailoring of key material parameters, especially stoichiometry, is required. This paper reviews the state of the art of growing large stoichiometric LiNbO{sub 3} (sLN) crystals, in particular, the defect engineering of pure and doped sLN with emphasis on optical damage resistant (ODR) dopants (e.g., Mg, Zn, In, Sc, Hf, Zr, Sn). The discussion is focused on crystals grown by the high temperature top seeded solution growth (HTTSSG) technique using alkali oxide fluxing agents. Based on high-temperature phase equilibria studies of the Li{sub 2}O–Nb{sub 2}O{sub 5}–X{sub 2}O ternary systems (X = Na, K, Rb, Cs), the impact of alkali homologue additives on the stoichiometry of the lithium niobate phase will be analyzed, together with a summary of the ultraviolet, infrared, and far-infrared absorption spectroscopic methods developed to characterize the composition of the crystals. It will be shown that using HTTSSG from K{sub 2}O containing flux, crystals closest to the stoichiometric composition can be grown characterized by a UV-edge position of at about 302 nm and a single narrow hydroxyl band in the IR with a linewidth of less than 3 cm{sup −1} at 300 K. The threshold concentrations for ODR dopants depend on crystal stoichiometry and the valence of the dopants; Raman spectra, hydroxyl vibration spectra, and Z-scan measurements prove to be useful to distinguish crystals below and above the photorefractive threshold. Crystals just above the threshold are

  3. Extended Aging Theories for Predictions of Safe Operational Life of Critical Airborne Structural Components

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Chen, Tony

    2006-01-01

    The previously developed Ko closed-form aging theory has been reformulated into a more compact mathematical form for easier application. A new equivalent loading theory and empirical loading theories have also been developed and incorporated into the revised Ko aging theory for the prediction of a safe operational life of airborne failure-critical structural components. The new set of aging and loading theories were applied to predict the safe number of flights for the B-52B aircraft to carry a launch vehicle, the structural life of critical components consumed by load excursion to proof load value, and the ground-sitting life of B-52B pylon failure-critical structural components. A special life prediction method was developed for the preflight predictions of operational life of failure-critical structural components of the B-52H pylon system, for which no flight data are available.

  4. Effects of ultrasonication on increased germination and improved seedling growth of aged grass seeds of tall fescue and Russian wildrye

    PubMed Central

    Liu, Juan; Wang, Quanzhen; Karagić, Đura; Liu, Xv; Cui, Jian; Gui, Jing; Gu, Muyu; Gao, Wei

    2016-01-01

    The effects of ultrasonic treatments on the germination and seedling growth of aged tall fescue (Festuca arundinacea) and Russian wild rye (Psathyrostaehys juncea Nevski) seeds were determined using orthogonal matrix experimental design with four ultrasonic factors. The multivariate analysis of variance detected significant differences and coupling effects of the pair-wise factors. The activities of Superoxide Dismutase (SOD) and Peroxidase (POD) and the Malondialdehyde (MDA) content were affected. The ultrasonic treatments had positive effects on the germination percentage (GP) of the aged seeds and the growth of the seedlings (GS) and therefore we provided a basic evidence for the application of ultrasonic treatment to pretreat aged grass seeds. For the four ultrasonic factors, the optimal conditions were a sonication time of 36.7 min, a sonication temperature of 35 °C, an output power of 367 W and a seed soaking time 4.1 h after binary quadratic regressions analyses. The ultrasonic treatment has the potential to improve seedling growth. Moreover, the longevity of the tall fescue and the Russian wild rye seeds was approximately 9.5 and 11.5 years, respectively, under natural conditions of storage. The physiological mechanisms that might contribute to the improved GP and GS were discussed. PMID:26928881

  5. Age and growth of the Scalloped Hammerhead shark, Sphyrna lewini (Griffith and Smith, 1834), from the southern Brazilian coast.

    PubMed

    Kotas, J E; Mastrochirico, V; Petrere Junior, M

    2011-08-01

    Age and growth studies for the scalloped hammerhead shark, Sphyrna lewini (Griffith and Smith, 1834) caught along the southern Brazilian coast, were based on ring measurements of vertebrae sections of 115 males, 116 females and 14 unknown sexed sharks between 48 and 344 cm total length (TL). The von Bertalanffy growth models were best fit using back-calculated data. The growth parameters obtained for males, were L∞ = 266 cm; K = 0.05/year; L0 = 47 cm. For females, L∞ = 300 cm; K = 0.05/year; L0 = 51 cm. An adult female reached 217 cm TL and was 31.5 years old. On the other hand, an adult male was 29.5 years old and measured 234 cm TL. Longevity estimate for males and females was 55 years. Therefore, S. lewini is a long-lived fish. Ageing precision, based on the IAPE index, was 5.6%. Marginal Increment analysis based on MIR index from hammerheads smaller than 105 cm, compared with the percentual of opaque and hyaline bands found per month ageing whole vertebrae, showed an annual ring formation, i.e., in winter. PMID:21881801

  6. Effects of ultrasonication on increased germination and improved seedling growth of aged grass seeds of tall fescue and Russian wildrye.

    PubMed

    Liu, Juan; Wang, Quanzhen; Karagić, Đura; Liu, Xv; Cui, Jian; Gui, Jing; Gu, Muyu; Gao, Wei

    2016-01-01

    The effects of ultrasonic treatments on the germination and seedling growth of aged tall fescue (Festuca arundinacea) and Russian wild rye (Psathyrostaehys juncea Nevski) seeds were determined using orthogonal matrix experimental design with four ultrasonic factors. The multivariate analysis of variance detected significant differences and coupling effects of the pair-wise factors. The activities of Superoxide Dismutase (SOD) and Peroxidase (POD) and the Malondialdehyde (MDA) content were affected. The ultrasonic treatments had positive effects on the germination percentage (GP) of the aged seeds and the growth of the seedlings (GS) and therefore we provided a basic evidence for the application of ultrasonic treatment to pretreat aged grass seeds. For the four ultrasonic factors, the optimal conditions were a sonication time of 36.7 min, a sonication temperature of 35 °C, an output power of 367 W and a seed soaking time 4.1 h after binary quadratic regressions analyses. The ultrasonic treatment has the potential to improve seedling growth. Moreover, the longevity of the tall fescue and the Russian wild rye seeds was approximately 9.5 and 11.5 years, respectively, under natural conditions of storage. The physiological mechanisms that might contribute to the improved GP and GS were discussed. PMID:26928881

  7. Sleep Duration and Age-Related Changes in Brain Structure and Cognitive Performance

    PubMed Central

    Lo, June C.; Loh, Kep Kee; Zheng, Hui; Sim, Sam K.Y.; Chee, Michael W.L.

    2014-01-01

    Study Objectives: To investigate the contribution of sleep duration and quality to age-related changes in brain structure and cognitive performance in relatively healthy older adults. Design: Community-based longitudinal brain and cognitive aging study using a convenience sample. Setting: Participants were studied in a research laboratory. Participants: Relatively healthy adults aged 55 y and older at study commencement. Interventions: N/A. Measurements and Results: Participants underwent magnetic resonance imaging and neuropsychological assessment every 2 y. Subjective assessments of sleep duration and quality and blood samples were obtained. Each hour of reduced sleep duration at baseline augmented the annual expansion rate of the ventricles by 0.59% (P = 0.007) and the annual decline rate in global cognitive performance by 0.67% (P = 0.050) in the subsequent 2 y after controlling for the effects of age, sex, education, and body mass index. In contrast, global sleep quality at baseline did not modulate either brain or cognitive aging. High-sensitivity C-reactive protein, a marker of systemic inflammation, showed no correlation with baseline sleep duration, brain structure, or cognitive performance. Conclusions: In healthy older adults, short sleep duration is associated with greater age-related brain atrophy and cognitive decline. These associations are not associated with elevated inflammatory responses among short sleepers. Citation: Lo JC, Loh KK, Zheng H, Sim SK, Chee MW. Sleep duration and age-related changes in brain structure and cognitive performance. SLEEP 2014;37(7):1171-1178. PMID:25061245

  8. Systematic screen for mutants resistant to TORC1 inhibition in fission yeast reveals genes involved in cellular ageing and growth

    PubMed Central

    Rallis, Charalampos; López-Maury, Luis; Georgescu, Teodora; Pancaldi, Vera; Bähler, Jürg

    2014-01-01

    Summary Target of rapamycin complex 1 (TORC1), which controls growth in response to nutrients, promotes ageing in multiple organisms. The fission yeast Schizosaccharomyces pombe emerges as a valuable genetic model system to study TORC1 function and cellular ageing. Here we exploited the combinatorial action of rapamycin and caffeine, which inhibit fission yeast growth in a TORC1-dependent manner. We screened a deletion library, comprising ∼84% of all non-essential fission yeast genes, for drug-resistant mutants. This screen identified 33 genes encoding functions such as transcription, kinases, mitochondrial respiration, biosynthesis, intra-cellular trafficking, and stress response. Among the corresponding mutants, 5 showed shortened and 21 showed increased maximal chronological lifespans; 15 of the latter mutants showed no further lifespan increase with rapamycin and might thus represent key targets downstream of TORC1. We pursued the long-lived sck2 mutant with additional functional analyses, revealing that the Sck2p kinase functions within the TORC1 network and is required for normal cell growth, global protein translation, and ribosomal S6 protein phosphorylation in a nutrient-dependent manner. Notably, slow cell growth was associated with all long-lived mutants while oxidative-stress resistance was not. PMID:24463365

  9. Age, growth, mortality, and reproduction of Roughtongue bass, Pronotogrammus martinicensis 9Serranidae), in the northeastern Gulf of Mexico

    USGS Publications Warehouse

    McBride, Richard S.; Sulak, Kenneth J.; Thurman, Paul E.; Richardson, Adam K.

    2009-01-01

    The inaccessibility of outer continental shelf reefs has made it difficult to investigate the biology of Pronotogrammus martinicensis, a small sea bass known to be numerous and widely distributed in such habitat. This study takes advantage of a series of cruises in the northeastern Gulf of Mexico that collected 1,485 individuals. Fish were collected over or in the vicinity of reef habitats with hook and line, otter trawl, and rotenone. We present a preliminary validation of an otolith ageing method and report that P. martinicensis reached a maximum size of 143 mm standard length (SL), grew to about 50% of this size within their first year, and lived to a maximum age of 15 yr. Size at age data (n = 490) fitted to the von Bertalanffy growth model yielded the predictive equation: SLt = 106.3(1 2 e [20.641{t20.646}]), where t = age in years. Gonad histology (n = 333) was examined to confirm that P. martinicensis is a protogynous, monandric hermaphrodite. We found no evidence of simultaneous hermaphroditism, which had been tentatively proposed in a previous study. Most P. martinicensis matured as females in their second year (age 1), primary oocytes developed asynchronously into secondary oocytes, and females were batch spawners. Males were postmaturational. Seminiferous tissue formed as early as age 1, but, although the rate of sex change is unknown, most fish did not function as a male until age 3 or age 4. These data provide age-based benchmarks of a common reef fish species living on the outer continental shelf of the tropical western North Atlantic Ocean.

  10. Spatial and temporal variation in age and growth in juvenile Loligo forbesi and relationships with recruitment in the English Channel and Scottish waters

    NASA Astrophysics Data System (ADS)

    Challier, Laurence; Pierce, Graham J.; Robin, Jean-Paul

    2006-04-01

    In many cephalopod stocks, resource abundance and fishing yields depend on the recruitment of the annual cohort. Loliginid squids such as Loligo forbesi are present in the English Channel and in Scottish waters. Variation in age and growth in juvenile Loligo forbesi of these two areas was investigated at the spatial and temporal scale, and inter-annual differences in growth were related to recruitment variation to test density dependence in squid growth in both populations. Spatial and temporal differences in growth were analysed in five cohorts that showed marked differences in recruitment abundance. Biological sampling showed that recruitment occurred in late autumn and spring in Scottish waters and in summer in the English Channel. In both fishing seasons, monthly samples collected at fish markets were analysed and ages of juveniles (mantle length < 200 mm) were determined using daily statolith growth increments. Age determination indicated that recruits were older than previously thought (about 8 to 11 months). Back-calculated hatching dates were used to estimate growth variation during the pre-recruitment stage. Exponential growth models adequately described size-at-age data. Linear modelling demonstrated inter-annual and spatial significant differences in growth rates. Influence of the hatching month (within or between cohorts) on growth was detected. To improve our understanding of recruitment variability, this study addresses the question: Does early growth vary in relation with recruitment? Available recruitment estimates appeared to be related to annual growth rates; density dependence in squid growth is suggested for the English Channel population.

  11. Growth of tapered silica nanowires with a shallow U-shaped vapor chamber: Growth mechanism and structural and optical properties

    SciTech Connect

    Zhang, Danqing; Zhang, Xi Wei, Jianglin; Gu, Gangxu; Xiang, Gang

    2015-04-28

    Traditional chemical vapor deposition method modified with a shallow U-shaped vapor chamber has been used to synthesize tapered bamboo shoot-like (BS-like) amorphous SiO{sub 2} nanowires (NWs) on Si (100) substrates without catalyst. The key innovation of this approach lies in a creation of swirling flow of the reactant vapors during the growth, which leads to a harvest of tapered silica NWs with lengths up to several microns. The unique structures and corresponding luminescence properties of the BS-like NWs were studied and their relationship with the evaporated active reactants was explored. A thermodynamic model that considers the critical role of the vapor flow during the growth is proposed to understand the structural and optical features. The shallow U-shaped vapor chamber-aided approach may provide a viable way to tailor novel structure of NWs for potential applications in nano-devices.

  12. Growth of tapered silica nanowires with a shallow U-shaped vapor chamber: Growth mechanism and structural and optical properties

    NASA Astrophysics Data System (ADS)

    Zhang, Danqing; Zhang, Xi; Wei, Jianglin; Gu, Gangxu; Xiang, Gang

    2015-04-01

    Traditional chemical vapor deposition method modified with a shallow U-shaped vapor chamber has been used to synthesize tapered bamboo shoot-like (BS-like) amorphous SiO2 nanowires (NWs) on Si (100) substrates without catalyst. The key innovation of this approach lies in a creation of swirling flow of the reactant vapors during the growth, which leads to a harvest of tapered silica NWs with lengths up to several microns. The unique structures and corresponding luminescence properties of the BS-like NWs were studied and their relationship with the evaporated active reactants was explored. A thermodynamic model that considers the critical role of the vapor flow during the growth is proposed to understand the structural and optical features. The shallow U-shaped vapor chamber-aided approach may provide a viable way to tailor novel structure of NWs for potential applications in nano-devices.

  13. A longitudinal study of structural brain network changes with normal aging

    PubMed Central

    Wu, Kai; Taki, Yasuyuki; Sato, Kazunori; Qi, Haochen; Kawashima, Ryuta; Fukuda, Hiroshi

    2013-01-01

    The aim of this study was to investigate age-related changes in the topological organization of structural brain networks by applying a longitudinal design over 6 years. Structural brain networks were derived from measurements of regional gray matter volume and were constructed in age-specific groups from baseline and follow-up scans. The structural brain networks showed economical small-world properties, providing high global and local efficiency for parallel information processing at low connection costs. In the analysis of the global network properties, the local and global efficiency of the baseline scan were significantly lower compared to the follow-up scan. Moreover, the annual rate of change in local and global efficiency showed a positive and negative quadratic correlation with the baseline age, respectively; both curvilinear correlations peaked at approximately the age of 50. In the analysis of the regional nodal properties, significant negative correlations between the annual rate of change in nodal strength and the baseline age were found in the brain regions primarily involved in the visual and motor/control systems, whereas significant positive quadratic correlations were found in the brain regions predominately associated with the default-mode, attention, and memory systems. The results of the longitudinal study are consistent with the findings of our previous cross-sectional study: the structural brain networks develop into a fast distribution from young to middle age (approximately 50 years old) and eventually became a fast localization in the old age. Our findings elucidate the network topology of structural brain networks and its longitudinal changes, thus enhancing the understanding of the underlying physiology of normal aging in the human brain. PMID:23565087

  14. Brain white matter structure and information processing speed in healthy older age.

    PubMed

    Kuznetsova, Ksenia A; Maniega, Susana Muñoz; Ritchie, Stuart J; Cox, Simon R; Storkey, Amos J; Starr, John M; Wardlaw, Joanna M; Deary, Ian J; Bastin, Mark E

    2016-07-01

    Cognitive decline, especially the slowing of information processing speed, is associated with normal ageing. This decline may be due to brain cortico-cortical disconnection caused by age-related white matter deterioration. We present results from a large, narrow age range cohort of generally healthy, community-dwelling subjects in their seventies who also had their cognitive ability tested in youth (age 11 years). We investigate associations between older age brain white matter structure, several measures of information processing speed and childhood cognitive ability in 581 subjects. Analysis of diffusion tensor MRI data using Tract-based Spatial Statistics (TBSS) showed that all measures of information processing speed, as well as a general speed factor composed from these tests (g speed), were significantly associated with fractional anisotropy (FA) across the white matter skeleton rather than in specific tracts. Cognitive ability measured at age 11 years was not associated with older age white matter FA, except for the g speed-independent components of several individual processing speed tests. These results indicate that quicker and more efficient information processing requires global connectivity in older age, and that associations between white matter FA and information processing speed (both individual test scores and g speed), unlike some other aspects of later life brain structure, are generally not accounted for by cognitive ability measured in youth. PMID:26254904

  15. 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.

  16. Application of Bayesian Hierarchical Model for Detecting Effective Factors on Growth Failure of Infants Less Than Two Years of Age in a Multicenter Longitudinal Study

    PubMed Central

    Zayeri, Farid; Amini, Maedeh; Moghimbeigi, Abbas; Soltanian, Ali Reza; Kholdi, Nahid; Gholami-Fesharaki, Mohammad

    2016-01-01

    Background Nowadays, one of the major public health problems among children is growth failure. It can be characterized in terms of either inadequate growth or the inability to maintain growth. Objectives The main objective of this study was to examine the effects of some factors on growth failure among a sample of infants less than two years old. Materials and Methods The present longitudinal archival study relied on data gathered from health files from February 2007 to July 2010 for 1,358 children under two years of age, selected from eight health centers in the east and northeast parts of Tehran, Iran. In the present study, growth failure refers to at least a 50 g decrease in an infant’s weight as recorded at each attendance in comparison to the previous measurement. The impacts of risk indicators were assessed using the Bayesian hierarchical logistic regression modeling technique. Results The highest and lowest percentage of growth failure was 5.8% and 0.1%, respectively, in the eleventh and the first month after birth. The obtained results from the Bayesian hierarchical modeling revealed that diarrhea (95% credible interval (CrI): 0.70 - 3.31), discontinuation of breastfeeding (95% CrI: 0.77 - 5.96), and respiratory infections (95% CrI: 2.07 - 4.61) were significant risk factors for growth failure. The random term at the child level was significant (95% CrI: 0.74 - 7.82), while the variation in centers was extremely small (95% CrI: 0.004 - 4.22). Conclusions It was noted that a relatively high prevalence of growth failure was observed in the study sample. For minimizing the impact of significant risk factors on growth failure, the early detection of growth failure and its risk indicators is of great importance. In addition, when the focus of the analysis is on the different nested sources of variability and the data has a hierarchical structure, using a hierarchical modeling approach is recommended to achieve more accurate results.

  17. Age-Related Yield of Adipose-Derived Stem Cells Bearing the Low-Affinity Nerve Growth Factor Receptor

    PubMed Central

    González-Garza, Maria Teresa; Cardenas-Lopez, Alejandro; Chavez-Castilla, Luis; Cruz-Vega, Delia Elva; Moreno-Cuevas, Jorge E.

    2013-01-01

    Adipose-derived stem cells (ADSCs) are a heterogeneous cell population that may be enriched by positive selection with antibodies against the low-affinity nerve growth factor receptor (LNGFR or CD271), yielding a selective cell universe with higher proliferation and differentiation potential. This paper addresses the need for determining the quantity of ADSCs positive for the CD271 receptor and its correlation with donor's age. Mononuclear cells were harvested from the lower backs of 35 female donors and purified using magnetic beads. Multipotency capacity was tested by the expression of stemness genes and through differentiation into preosteoblasts and adipocytes. A significant statistical difference was found in CD271+ concentrations between defined age intervals. The highest yield was found within women on the 30–40-year-old age range. CD271+ ADSCs from all age groups showed differentiation capabilities as well as expression of typical multipotent stem cell genes. Our data suggest that the amount of CD271+ cells correlates inversely with age. However, the ability to obtain these cells was maintained through all age ranges with a yield higher than what has been reported from bone marrow. Our findings propose CD271+ ADSCs as the primary choice for tissue regeneration and autologous stem cell therapies in older subjects. PMID:24376462

  18. Growth hormone (GH)–releasing hormone and GH secretagogues in normal aging: Fountain of Youth or Pool of Tantalus?

    PubMed Central

    Hersch, Elizabeth C; Merriam, George R

    2008-01-01

    Although growth hormone (GH) is primarily associated with linear growth in childhood, it continues to have important metabolic functions in adult life. Adult GH deficiency (AGHD) is a distinct clinical entity, and GH replacement in AGHD can improve body composition, strength, aerobic capacity, and mood, and may reduce vascular disease risk. While there are some hormone-related side effects, the balance of benefits and risks is generally favorable, and several countries have approved GH for clinical use in AGHD. GH secretion declines progressively and markedly with aging, and many age-related changes resemble those of partial AGHD. This suggests that replacing GH, or stimulating GH with GH-releasing hormone or a GH secretagogue could confer benefits in normal aging similar to those observed in AGHD – in particular, could reduce the loss of muscle mass, strength, and exercise capacity leading to frailty, thereby prolonging the ability to live independently. However, while most GH studies have shown body composition effects similar to those in AGHD, functional changes have been much less inconsistent, and older adults are more sensitive to GH side effects. Preliminary reports of improved cognition are encouraging, but the overall balance of benefits and risks of GH supplementation in normal aging remains uncertain. PMID:18488883

  19. Goldeye, Hiodon alosoides, in Lake Oahe: abundance, age, growth, maturity, food, and the fishery, 1963-69

    USGS Publications Warehouse

    Miller, Grant L.; Nelson, William R.

    1974-01-01

    Reproductive success was relatively consistent, and adequate to maintain species abundance at a nearly constant level, during 1963-69. Both abundance and growth in length increased from the lower to the upper portion of the reservoir. In most characteristics -- growth in length, length-weight relation, age at maturity, and food -- goldeye in Lake Oahe were similar to those from other Missouri River impoundments. Experimental gill nets samples all lengths (range 80-460 mm; median, 320 mm) of goldeye, bottom trawls sampled mostly small fish, (median, 215 mm) and trap nets large ones (median, 345 mm). Commercial gill nets were highly size selective (median, 375 mm); fish of ages IV-VII made up 90% of the catch. Survival rates were 57 to 52% for ages II-X. Estimated survival rates for ages V-IX declined from 44 to 35% after the inception of the commercial fishery in 1966. The peak commercial catch was 151,432 kg (1.2 kg/hectare) in 1969. Unless recruitment declines, the population can support a fishery of that magnitude.

  20. Constrained, aqueous growth of three-dimensional single crystalline zinc oxide structures

    SciTech Connect

    Pooley, Kathryn J. Joo, John H.; Hu, Evelyn L.

    2014-01-01

    We study low temperature (90 °C) aqueous growth of single crystal zinc oxide structures through patterned PMMA molds of different sizes, shapes, and orientations. We demonstrate the ability to create 3D shapes with smooth vertical sidewalls. Although the unconstrained growth is influenced by the hexagonal geometry of the underlying crystal structure, the ZnO is shown to conform exactly to any shape patterned. Using electron backscatter diffraction and scanning electron microscopy we show that the mold orientation, in conjunction with control of the growth rates of the c and m planes of the ZnO, is crucial in determining the final structure shape.

  1. Age and growth of flathead catfish, Pylodictus olivaris rafinesque, in the Altamaha River system, Georgia

    USGS Publications Warehouse

    Grabowski, T.B.; Isely, J.J.; Weller, R.R.

    2004-01-01

    Flathead catfish were introduced to the Altamaha River system, Georgia in the 1970's. We determined the length-weight relationship, Von Bertalanffy growth parameters, and back calculated lengths by examining the sagittal otoliths of 331 individuals captured from this population. We found that there were no sex related differences in length weight relationship or Von Bertalanffy growth parameters. Flathead catfish in the Altamaha River system grow at about the same rate as individuals in other introduced populations.

  2. Brain Structural Integrity and Intrinsic Functional Connectivity Forecast 6 Year Longitudinal Growth in Children's Numerical Abilities

    PubMed Central

    Kochalka, John; Ngoon, Tricia J.; Wu, Sarah S.; Qin, Shaozheng; Battista, Christian

    2015-01-01

    Early numerical proficiency lays the foundation for acquiring quantitative skills essential in today's technological society. Identification of cognitive and brain markers associated with long-term growth of children's basic numerical computation abilities is therefore of utmost importance. Previous attempts to relate brain structure and function to numerical competency have focused on behavioral measures from a single time point. Thus, little is known about the brain predictors of individual differences in growth trajectories of numerical abilities. Using a longitudinal design, with multimodal imaging and machine-learning algorithms, we investigated whether brain structure and intrinsic connectivity in early childhood are predictive of 6 year outcomes in numerical abilities spanning childhood and adolescence. Gray matter volume at age 8 in distributed brain regions, including the ventrotemporal occipital cortex (VTOC), the posterior parietal cortex, and the prefrontal cortex, predicted longitudinal gains in numerical, but not reading, abilities. Remarkably, intrinsic connectivity analysis revealed that the strength of functional coupling among these regions also predicted gains in numerical abilities, providing novel evidence for a network of brain regions that works in concert to promote numerical skill acquisition. VTOC connectivity with posterior parietal, anterior temporal, and dorsolateral prefrontal cortices emerged as the most extensive network predicting individual gains in numerical abilities. Crucially, behavioral measures of mathematics, IQ, working memory, and reading did not predict children's gains in numerical abilities. Our study identifies, for the first time, functional circuits in the human brain that scaffold the development of numerical skills, and highlights potential biomarkers for identifying children at risk for learning difficulties. SIGNIFICANCE STATEMENT Children show substantial individual differences in math abilities and ease of math

  3. Precision growth index using the clustering of cosmic structures and growth data

    SciTech Connect

    Pouri, Athina; Basilakos, Spyros; Plionis, Manolis E-mail: svasil@academyofathens.gr

    2014-08-01

    We use the clustering properties of Luminous Red Galaxies (LRGs) and the growth rate data provided by the various galaxy surveys in order to constrain the growth index γ) of the linear matter fluctuations. We perform a standard χ{sup 2}-minimization procedure between theoretical expectations and data, followed by a joint likelihood analysis and we find a value of γ=0.56± 0.05, perfectly consistent with the expectations of the ΛCDM model, and Ω{sub m0} =0.29± 0.01, in very good agreement with the latest Planck results. Our analysis provides significantly more stringent growth index constraints with respect to previous studies, as indicated by the fact that the corresponding uncertainty is only ∼ 0.09 γ. Finally, allowing γ to vary with redshift in two manners (Taylor expansion around z=0, and Taylor expansion around the scale factor), we find that the combined statistical analysis between our clustering and literature growth data alleviates the degeneracy and obtain more stringent constraints with respect to other recent studies.

  4. Long-term reorganization of structural brain networks in a rabbit model of intrauterine growth restriction.

    PubMed

    Batalle, Dafnis; Muñoz-Moreno, Emma; Arbat-Plana, Ariadna; Illa, Miriam; Figueras, Francesc; Eixarch, Elisenda; Gratacos, Eduard

    2014-10-15

    Characterization of brain changes produced by intrauterine growth restriction (IUGR) is among the main challenges of modern fetal medicine and pediatrics. This condition affects 5-10% of all pregnancies and is associated with a wide range of neurodevelopmental disorders. Better understanding of the brain reorganization produced by IUGR opens a window of opportunity to find potential imaging biomarkers in order to identify the infants with a high risk of having neurodevelopmental problems and apply therapies to improve their outcomes. Structural brain networks obtained from diffusion magnetic resonance imaging (MRI) is a promising tool to study brain reorganization and to be used as a biomarker of neurodevelopmental alterations. In the present study this technique is applied to a rabbit animal model of IUGR, which presents some advantages including a controlled environment and the possibility to obtain high quality MRI with long acquisition times. Using a Q-Ball diffusion model, and a previously published rabbit brain MRI atlas, structural brain networks of 15 IUGR and 14 control rabbits at 70 days of age (equivalent to pre-adolescence human age) were obtained. The analysis of graph theory features showed a decreased network infrastructure (degree and binary global efficiency) associated with IUGR condition and a set of generalized fractional anisotropy (GFA) weighted measures associated with abnormal neurobehavior. Interestingly, when assessing the brain network organization independently of network infrastructure by means of normalized networks, IUGR showed increased global and local efficiencies. We hypothesize that this effect could reflect a compensatory response to reduced infrastructure in IUGR. These results present new evidence on the long-term persistence of the brain reorganization produced by IUGR that could underlie behavioral and developmental alterations previously described. The described changes in network organization have the potential to be used

  5. First trimester fetal growth restriction and cardiovascular risk factors in school age children: population based cohort study

    PubMed Central

    de Jonge, Layla L; Hofman, Albert; Franco, Oscar H; Steegers, Eric A P; Gaillard, Romy

    2014-01-01

    Objective To examine whether first trimester fetal growth restriction correlates with cardiovascular outcomes in childhood. Design Population based prospective cohort study. Setting City of Rotterdam, the Netherlands. Participants 1184 children with first trimester fetal crown to rump length measurements, whose mothers had a reliable first day of their last menstrual period and a regular menstrual cycle. Main outcomes measures Body mass index, total and abdominal fat distribution, blood pressure, and blood concentrations of cholesterol, triglycerides, insulin, and C peptide at the median age of 6.0 (90% range 5.7-6.8) years. Clustering of cardiovascular risk factors was defined as having three or more of: high android fat mass; high systolic or diastolic blood pressure; low high density lipoprotein cholesterol or high triglycerides concentrations; and high insulin concentrations. Results One standard deviation score greater first trimester fetal crown to rump length was associated with a lower total fat mass (−0.30%, 95% confidence interval −0.57% to −0.03%), android fat mass (−0.07%, −0.12% to −0.02%), android/gynoid fat mass ratio (−0.53, −0.89 to −0.17), diastolic blood pressure (−0.43, −0.84 to −0.01, mm Hg), total cholesterol (−0.05, −0.10 to 0, mmol/L), low density lipoprotein cholesterol (−0.04, −0.09 to 0, mmol/L), and risk of clustering of cardiovascular risk factors (relative risk 0.81, 0.66 to 1.00) in childhood. Additional adjustment for gestational age and weight at birth changed these effect estimates only slightly. Childhood body mass index fully explained the associations of first trimester fetal crown to rump length with childhood total fat mass. First trimester fetal growth was not associated with other cardiovascular outcomes. Longitudinal growth analyses showed that compared with school age children without clustering of cardiovascular risk factors, those with clustering had a smaller first trimester fetal crown

  6. Age estimation of juvenile European hake Merluccius merluccius based on otolith microstructure analysis: a slow or fast growth pattern?

    PubMed

    Pattoura, P; Lefkaditou, E; Megalofonou, P

    2015-03-01

    The main goal of this study was to examine otolith microstructure and to estimate the age and growth of European hake Merluccius merluccius from the eastern Mediterranean Sea. One hundred and twenty-nine specimens ranging from 102 to 438 mm in total length (LT ) were used. Age estimations were based on the study of the otolith microstructure, which was revealed after grinding both frontal sides of otoliths. The enumerations of the daily growth increments (DGI) as well as their width (WDGI ) measurements were made on calibrated digital images. The number of DGI in otoliths ranged between 163 and 717. Four phases in the WDGI evolution were distinguished: (1) larval-juvenile pelagic phase, with an increasing trend in WDGI up to the 60th DGI, (2) settlement phase, with a short-term deceleration in WDGI between the 61st and 150th DGI, (3) juvenile demersal phase, characterized by a stabilization of WDGI from 151st to 400th DGI and (4) adult phase, with a decreasing trend in WDGI after the 400th DGI. Age, sex and month of formation were found to affect the WDGI in all phases, with the exception of age at the juvenile demersal phase. The power curve with intercept model described best the relationship of M. merluccius LT with age (TDGI ), according to Akaike criteria, revealing differences in growth between females [LT = 65 · 36(TDGI )(0 · 40) - 388 · 55] and males [LT = 69 · 32(TDGI )(0 · 37) - 352 · 88] for the sizes examined. The mean daily growth rates were 0·61 mm day(-1) for females and 0·52 mm day(-1) for males, resulting in an LT of 283 and 265 mm at the end of their first year of life. In comparison with previous studies on the Mediterranean Sea, the results of this study showed a greater growth rate, similar to results from tagging experiments and otolith microstructure analyses for M. merluccius in other geographic areas. PMID:25545134

  7. Structural evolution of gold nanorods during controlled secondary growth.

    PubMed

    Keul, Heidrun A; Möller, Martin; Bockstaller, Michael R

    2007-09-25

    Single-crystalline gold nanorods synthesized by the Ag(I)-mediated seeded-growth method (see: El-Sayed, M. A.; Nikoobakht, B. Chem. Mater. 2003, 15, 1957) were used as seeds for the preferential overgrowth of gold on particular crystallographic facets by systematic variation of the conditions during overgrowth. The results support previous reports about the relevance of the cationic surfactant cetyltrimethylammonium bromide (CTAB) and Ag(I) in stabilizing anisotropic particle shapes and demonstrate that the regulation of the amount of ascorbic acid facilitates the preferential overgrowth of {111} crystal facets to form Xi-type particle shapes. Interestingly, secondary overgrowth is found to inevitably result in a loss of particle shape anisotropy. A mechanism based on surface reconstruction is proposed to rationalize the "shape-reversal" that is generally observed in the nanorod growth process, that is, the initial increase and subsequent decrease of particle anisotropy with increasing reaction time. High-resolution electron microscopy analysis of gold nanorods reveals clear evidence for (1 x 2) missing row surface reconstruction of high energetic {110} facets that form during the initial phase during particle growth. PMID:17713936

  8. The age-sex structure of the slave population in Harris County, Texas: 1850 and 1860.

    PubMed

    Hutchinson, J

    1987-10-01

    The effect of the slave system on demography can be revealed by examining the age-sex structure of slave populations. The age-sex structure of slaves in Harris County, Texas is investigated using the 1850 and 1860 slave schedules. Median ages for black and mulatto slaves suggest that the population was young. Population pyramids exhibit a narrow base and top with a broad middle. The high proportion of slaves between 10 and 30 years of age and the increase in population size between 1850 and 1860 were mainly related to the importation of slaves and only partly due to natural increase. The data also show that black slaves were older on small plantations while mulattoes were older on larger farms. It is suggested that differential treatment in terms of purchase practices, assignment of tasks, food allocation, and/or differential susceptibility to infectious diseases may account for this pattern. PMID:3322029

  9. The effect of collagen ageing on its structure and cellular behaviour

    NASA Astrophysics Data System (ADS)

    Wilson, Samantha L.; Guilbert, Marie; Sulé-Suso, Josep; Torbet, James; Jeannesson, Pierre; Sockalingum, Ganesh D.; Yang, Ying

    2012-03-01

    Collagen is the most important component in extracellular matrix (ECM) and plays a pivotal role in individual tissue function in mammals. During ageing, collagen structure changes, which can detrimentally affect its biophysical and biomechanical properties due to an accumulation of advanced glycation end-products (AGEs). AGEs have been linked to non-enzymatic cross-linking of proteins resulting in the alteration of mechanical properties of the tissue. In this study we investigate the influence of different aged collagens on the mechanical and contractile properties of reconstituted hydrogel constructs seeded with corneal stromal fibroblasts. A non-destructive indentation technique and optical coherence tomography (OCT) are used to determine the elastic modulus and dimensional changes respectively. It is revealed that the youngest collagen constructs have a higher elastic modulus and increased contraction compared to the older collagen. These results provide new insights into the relationship between collagen molecular structures and their biomechanical properties.

  10. Difference in growth hormone response to growth hormone-releasing hormone (GHRH) testing following GHRH subacute treatment in normal aging and growth hormone-deficient adults: possible perspectives for therapeutic use of GHRH or its analogs in elderly subjects?

    PubMed

    Iovino, M; Triggiani, V; Giagulli, V A; Iovine, N; Licchelli, B; Resta, F; Sabbà, C; Tafaro, E; Solimando, A; Tommasicchio, A; Guastamacchia, E

    2011-06-01

    The somatotroph axis function shows a decline in the elderly (somatopause). In particular growth hormone (GH) response to GH-releasing hormone (GHRH) is reduced in aged man but less than that observed in GH-deficient adults (GHDAs). Plasma GH response to GHRH (1 µg/kg BW) was significantly lower in four GHDAs than in seven healthy aged men 30, 60, and 90 min after acute GHRH administration. To verify whether a priming regimen might be able to increase the reduced GH response to GHRH, both healthy aged men and GHDA patients underwent repetitive administration of GHRH (100 µg GHRH intravenously as a single morning dose, every 2 days for 12 days). After the GHRH-priming regimen, plasma GH values 30, 60, and 90 min after the acute GHRH test were significantly higher than values at the corresponding time points before priming regimen in healthy aged men but not in GHDA patients. These findings confirmed that somatotroph cells become less sensitive to GHRH with normal aging and demonstrate that repetitive administration of GHRH restores the attenuated response only in healthy aged men but not in GHDA patients. This could support the possible use of GHRH or its analogs instead of recombinant human GH in elderly patients with the advantage of preserving the endogenous pulses of GH with the secretion of the different isoforms of GH. However, concerns arise about the possible role of these molecules in tumorigenesis and tumor growth promotion. PMID:20843274

  11. Alterations in nocturnal serum melatonin levels in humans with growth and aging.

    PubMed

    Waldhauser, F; Weiszenbacher, G; Tatzer, E; Gisinger, B; Waldhauser, M; Schemper, M; Frisch, H

    1988-03-01

    The available data on potential alterations in serum melatonin (MLT) levels during a human lifetime are fragmentary and inconsistent. We, therefore, measured day- and nighttime serum MLT concentrations in 367 subjects (210 males and 157 females), aged 3 days to 90 yr. Blood samples were collected between 0730 and 1000 h and between 2300 and 0100 h. Serum MLT levels were measured by RIA. The mean nighttime serum MLT concentration was low during the first 6 months of life, i.e. 27.3 +/- 5.4 (+/- SE) pg/mL (0.12 +/- 0.02 nmol/L). It then increased to a peak value at 1-3 yr of age [329.5 +/- 42.0 pg/mL; (1.43 +/- 0.18 nmol/L)], and it was considerably lower [62.5 +/- 9.0 pg/mL; (0.27 +/- 0.04 nmol/L)] in individuals aged 15-20 yr. During the following decades serum MLT declined moderately until old age (70-90 yr of age), i.e. 29.2 +/- 6.1 pg/mL (0.13 +/- 0.03 nmol/L). This biphasic MLT decline follows 2 exponential functions with different slopes (from age 1-20 yr: r = -0.56; P less than 0.001; y = 278.7 X e -0.09x; from age 20-90 yr: r = -0.44; P less than 0.001; y = 84.8 X e -0.017x). The decrease in nocturnal serum MLT in children and adolescents (1-20 yr) correlated with the increase in body weight (r = -0.54; P less than 0.001) and body surface area (r = -0.71; P less than 0.001). At a later age (20-90 yr) there was no correlation among these variables. Daytime serum MLT levels were low and no age-related alterations were found. This study revealed major age-related alterations in nocturnal serum MLT levels. The negative correlation between serum MLT and body weight in childhood and adolescence is evidence that expansion of body size is responsible for the huge MLT decrease during that period. The moderate decline at older ages must derive from other factors. PMID:3350912

  12. Interactions between hatch dates, growth rates, and mortality of Age-0 native Rainbow Smelt and nonnative Alewife in Lake Champlain

    USGS Publications Warehouse

    Parrish, Donna; Simonin, Paul W.; Rudstam, Lars G.; Pientka, Bernard; Sullivan, Patrick J.

    2016-01-01

    Timing of hatch in fish populations can be critical for first-year survival and, therefore, year-class strength and subsequent species interactions. We compared hatch timing, growth rates, and subsequent mortality of age-0 Rainbow Smelt Osmerus mordax and Alewife Alosa pseudoharengus, two common open-water fish species of northern North America. In our study site, Lake Champlain, Rainbow Smelt hatched (beginning May 26) almost a month earlier than Alewives (June 20). Abundance in the sampling area was highest in July for age-0 Rainbow Smelt and August for age-0 Alewives. Late-hatching individuals of both species grew faster than those hatching earlier (0.6 mm/d versus 0.4 for Rainbow Smelt; 0.7 mm/d versus 0.6 for Alewives). Mean mortality rate during the first 45 d of life was 3.4%/d for age-0 Rainbow Smelt and was 5.5%/d for age-0 Alewives. Alewife mortality rates did not differ with hatch timing but daily mortality rates of Rainbow Smelt were highest for early-hatching fish. Cannibalism is probably the primary mortality source for age-0 Rainbow Smelt in this lake. Therefore, hatching earlier may not be advantageous because the overlap of adult and age-0 Rainbow Smelt is highest earlier in the season. However, Alewives, first documented in Lake Champlain in 2003, may increase the mortality of age-0 Rainbow Smelt in the summer, which should favor selection for earlier hatching.

  13. Arterial structure and function in vascular ageing: are you as old as your arteries?

    PubMed

    Thijssen, Dick H J; Carter, Sophie E; Green, Daniel J

    2016-04-15

    Advancing age may be the most potent independent predictor of future cardiovascular events, a relationship that is not fully explained by time-related changes in traditional cardiovascular risk factors. Since some arteries exhibit differential susceptibility to atherosclerosis, generalisations regarding the impact of ageing in humans may be overly simplistic, whereas in vivo assessment of arterial function and health provide direct insight. Coronary and peripheral (conduit, resistance and skin) arteries demonstrate a gradual, age-related impairment in vascular function that is likely to be related to a reduction in endothelium-derived nitric oxide bioavailability and/or increased production of vasoconstrictors (e.g. endothelin-1). Increased exposure and impaired ability for defence mechanisms to resist oxidative stress and inflammation, but also cellular senescence processes, may contribute to age-related changes in vascular function and health. Arteries also undergo structural changes as they age. Gradual thickening of the arterial wall, changes in wall content (i.e. less elastin, advanced glycation end-products) and increase in conduit artery diameter are observed with older age and occur similarly in central and peripheral arteries. These changes in structure have important interactive effects on artery function, with increases in small and large arterial stiffness representing a characteristic change with older age. Importantly, direct measures of arterial function and structure predict future cardiovascular events, independent of age or other cardiovascular risk factors. Taken together, and given the differential susceptibility of arteries to atherosclerosis in humans, direct measurement of arterial function and health may help to distinguish between biological and chronological age-related change in arterial health in humans. PMID:26140618

  14. Retrieving chronological age from dental remains of early fossil hominins to reconstruct human growth in the past

    PubMed Central

    Dean, M. Christopher

    2010-01-01

    A chronology of dental development in Pan troglodytes is arguably the best available model with which to compare and contrast reconstructed dental chronologies of the earliest fossil hominins. Establishing a time scale for growth is a requirement for being able to make further comparative observations about timing and rate during both dento-skeletal growth and brain growth. The absolute timing of anterior tooth crown and root formation appears not to reflect the period of somatic growth. In contrast, the molar dentition best reflects changes to the total growth period. Earlier initiation of molar mineralization, shorter crown formation times, less root length formed at gingival emergence into functional occlusion are cumulatively expressed as earlier ages at molar eruption. Things that are similar in modern humans and Pan, such as the total length of time taken to form individual teeth, raise expectations that these would also have been the same in fossil hominins. The best evidence there is from the youngest fossil hominin specimens suggests a close resemblance to the model for Pan but also hints that Gorilla may be a better developmental model for some. A mosaic of great ape-like features currently best describes the timing of early hominin dental development. PMID:20855313

  15. Cytochrome c oxidase loses catalytic activity and structural integrity during the aging process in Drosophila melanogaster

    PubMed Central

    Ren, Jian-Ching; Rebrin, Igor; Klichko, Vladimir; Orr, William C.; Sohal, Rajindar S.

    2010-01-01

    The hypothesis, that structural deterioration of cytochrome c oxidase (CcO) is a causal factor in the age-related decline in mitochondrial respiratory activity and an increase in H2O2 generation, was tested in Drosophila melanogaster. CcO activity and the levels of seven different nuclear DNA-encoded CcO subunits were determined at three different stages of adult life, namely, young-, middle- and old-age. CcO activity declined progressively with age by 33%. Western blot analysis, using antibodies specific to Drosophila CcO subunits IV, Va,