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Growth Trends (growth + trend)
Selected AbstractsIMF,Africa: Falling Growth TrendAFRICA RESEARCH BULLETIN: ECONOMIC, FINANCIAL AND TECHNICAL SERIES, Issue 2 2009Article first published online: 7 APR 200 No abstract is available for this article. [source] Bone and Muscle Development During Puberty in Girls: A Seven-Year Longitudinal Study,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2009Leiting Xu Abstract The growth of lean mass precedes that of bone mass, suggesting that muscle plays an important role in the growth of bone. However, to date, no study has directly followed the growth of bone and muscle size through puberty and into adulthood. This study aimed to test the hypothesis that the growth of muscle size precedes that of bone size (width and length) and mass during puberty. Bone and muscle properties were measured using pQCT and DXA in 258 healthy girls at baseline (mean age, 11.2 yr) and 1-, 2-, 3,4- and 7-yr follow-up. Growth trends as a function of time relative to menarche were determined from prepuberty to early adulthood for tibial length (TL), total cross-sectional area (tCSA), cortical CSA (cCSA), total BMC (tBMC), cortical volumetric BMD (cBMD), and muscle CSA (mCSA) in hierarchical models. The timings of the peak growth velocities for these variables were calculated. Seventy premenopausal adults, comprising a subset of the girl's mothers (mean age, 41.5 yr), were included for comparative purposes. In contrast to our hypothesis, the growth velocity of mCSA peaked 1 yr later than that of tibial outer dimensions (TL and tCSA) and slightly earlier than tBMC. Whereas TL ceased to increase 2 yr after menarche, tCSA, cCSA, tBMC, and mCSA continued to increase and were still significantly lower than adult values at the age of 18 yr (all p < 0.01). The results do not support the view that muscle force drives the growth of bone size during puberty. [source] Tropospheric O3 moderates responses of temperate hardwood forests to elevated CO2: a synthesis of molecular to ecosystem results from the Aspen FACE projectFUNCTIONAL ECOLOGY, Issue 3 2003D. F. Karnosky Summary 1The impacts of elevated atmospheric CO2 and/or O3 have been examined over 4 years using an open-air exposure system in an aggrading northern temperate forest containing two different functional groups (the indeterminate, pioneer, O3 -sensitive species Trembling Aspen, Populus tremuloides and Paper Birch, Betula papyrifera, and the determinate, late successional, O3 -tolerant species Sugar Maple, Acer saccharum). 2The responses to these interacting greenhouse gases have been remarkably consistent in pure Aspen stands and in mixed Aspen/Birch and Aspen/Maple stands, from leaf to ecosystem level, for O3 -tolerant as well as O3 -sensitive genotypes and across various trophic levels. These two gases act in opposing ways, and even at low concentrations (1·5 × ambient, with ambient averaging 34,36 nL L,1 during the summer daylight hours), O3 offsets or moderates the responses induced by elevated CO2. 3After 3 years of exposure to 560 µmol mol,1 CO2, the above-ground volume of Aspen stands was 40% above those grown at ambient CO2, and there was no indication of a diminishing growth trend. In contrast, O3 at 1·5 × ambient completely offset the growth enhancement by CO2, both for O3 -sensitive and O3 -tolerant clones. Implications of this finding for carbon sequestration, plantations to reduce excess CO2, and global models of forest productivity and climate change are presented. [source] Growth of osteoblast-like cells on biomimetic apatite-coated chitosan scaffoldsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2008I. Manjubala Abstract Porous scaffold materials that can provide a framework for the cells to adhere, proliferate, and create extracellular matrix are considered to be suitable materials for bone regeneration. Interconnected porous chitosan scaffolds were prepared by freeze-drying method, and were mineralized by calcium and phosphate solution by double-diffusion method to form nanoapatite in chitosan matrix. The mineralized chitosan scaffold contains hydroxyapatite nanocrystals on the surface and also within the pore channels of the scaffold. To assess the effect of apatite and porosity of the scaffolds on cells, human osteoblast (SaOS-2) cells were cultured on unmineralized and mineralized chitosan scaffolds. The cell growth on the mineralized scaffolds and on the pure chitosan scaffold shows a similar growth trend. The total protein content and alkaline phosphatase enzyme activity of the cells grown on scaffolds were quantified, and were found to increase over time in mineralized scaffold after 1 and 3 weeks of culture. The electron microscopy of the cell-seeded scaffolds showed that most of the outer macropores became sealed off by a continuous layer of cells. The cells spanned around the pore wall and formed extra cellular matrix, consisting mainly of collagen in mineralized scaffolds. The hydroxyproline content also confirmed the formation of the collagen matrix by cells in mineralized scaffolds. This study demonstrated that the presence of apatite nanocrystals in chitosan scaffolds does not significantly influence the growth of cells, but does induce the formation of extracellular matrix and therefore has the potential to serve for bone tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Population, Unemployment and Economic Growth Cycles: A Further Explanatory PerspectiveMETROECONOMICA, Issue 2-3 2003Luciano Fanati In this paper we investigate the dynamic interaction between economic growth, unemployment, income distribution and population growth. The reference framework combines rational behaviour of agents with endogenous fertility and unemployment, while profits are the determinant of the accumulation of firms. In particular the supply of labour is determined by the micro-founded fertility choices of individuals. We first demonstrate, consistently with the empirical evidence, the existence of a positive income growth trend with sustained oscillations, therefore providing an alternative explanation of the relation between growth and cycle. Moreover interesting results are given on the relation between unemployment and growth. So far the literature has traditionally shown a negative relation between unemployment and growth (with the exception of the positive relation arising in a Schumpeter ,creative' disruption context). In contrast, we find a twofold effect of unemployment (via its effects on population) on economic growth: this can be both positive or negative depending on the relative level of the cost of childrearing of employed and unemployed persons, and on the level of unemployment benefits. This allows us to argue that an increase in unemployment benefit,as has occurred in recent years in many countries such as France and Spain,could lead to wide demo-economic fluctuations and to a positive effect of unemployment on economic growth. [source] Developmental craniofacial anthropometry: Assessment of race effectsCLINICAL ANATOMY, Issue 7 2009Reid B. Durtschi Abstract Differences in craniofacial anatomy among racial groups have been documented in a variety of structures, but the oral and maxillofacial regions have been shown to be a particularly defining region of variability between different racial/ethnic groups. Such comparisons are informative, but they neither address developmental changes of the craniofacial anatomy nor do they assess or take into account the natural variability within individual races that may account for similar reported, across-group variations. The purpose of this report was to compare,using medical imaging studies,the growth trend of select race-sensitive craniofacial variables in the oral and pharyngeal regions when all races [White, Asian, Black, and Hispanic (AR)] are included versus only a single race category [White (WR)]. Race effect was tested by comparing sex-specific growth fits (fourth degree polynomial model) for AR versus WR data. Findings indicate that the inclusion of all races versus a single race did not significantly alter the growth model fits. Thus, the inclusion of all races permits the advancement of general growth models; however, methodologically, it is best to treat the race variable as a covariate in all future analysis to test for both potential all race effects or individual race effects, on general growth models. Clin. Anat. 22:800,808, 2009. © 2009 Wiley-Liss, Inc. [source] Rapid climate change-related growth decline at the southern range edge of Fagus sylvaticaGLOBAL CHANGE BIOLOGY, Issue 11 2006ALISTAIR S. JUMP Abstract Studies on Fagus sylvatica show that growth in populations toward the southern limit of this species' distribution is limited strongly by drought. Warming temperatures in the Mediterranean region are expected to exacerbate drought where they are not accompanied by increases in precipitation. We studied levels of annual growth in mature F. sylvatica trees over the last half-century in the Montseny Mountains in Catalonia (northeast Spain). Our results show significantly lower growth of mature trees at the lower limit of this species' distribution when compared with trees at higher altitudes. Growth at the lower Fagus limit is characterized by a rapid recent decline starting in approximately 1975. By 2003, growth of mature trees had fallen by 49% when compared with predecline levels. This is not an age-related phenomenon, nor is it seen in comparable populations at higher altitudes. Analysis of climate-growth relationships suggests that the observed decline in growth is a result of warming temperatures and that, as precipitation in the region has not increased, precipitation is now insufficient to ameliorate the negative effects of increased temperatures on tree growth. As the climate-response of the studied forest is comparable with that of F. sylvatica forests in other southern European regions, it is possible that this growth decline is a more widespread phenomenon. Warming temperatures may lead to a rapid decline in the growth of range-edge populations and a consequent retreat of the species distribution in southern Europe. Assessment of long-term growth trends across the southern range edge of F. sylvatica therefore merits further attention. [source] Public Education Financing Trends and the Gray Peril HypothesisGROWTH AND CHANGE, Issue 4 2009DAYTON M. LAMBERT ABSTRACT The effects of migrating seniors on the provision of local public services in rural communities is growing in importance because of the large number of retiring baby boomers and the increasing rate at which these retirees are locating outside traditional retirement destinations. Some communities are optimistic about attracting and retaining retirees as an economic development strategy, but others are concerned that inmigrating seniors may be reluctant to support local public services, such as education, bringing with them "Gray Peril." This article attempts to clarify questions regarding the Gray Peril hypothesis and local ability and willingness to fund education in Tennessee, an increasingly popular retirement destination. To this end, county per pupil education expenditure growth is explained by growth trends in local property tax assessment and sales tax revenue, and migration patterns of the retirement-aged population from 1962 to 2002. [source] Effects of density and ontogeny on size and growth ranks of three competing tree speciesJOURNAL OF ECOLOGY, Issue 2 2009Suzanne B. Boyden Summary 1Rank reversals in species performance are theoretically important for structuring communities, maintaining diversity and determining the course of forest succession. Species growth ranks can change with ontogeny or in different microenvironments, but interactions between ontogeny and the environment are not well-understood because of the lack of long-term forest competition studies. While early differences in growth among species may reflect intrinsic differences in shade-tolerance and physiology, ontogenetic trends in growth and variation in neighbourhood density and composition may change or even reverse early patterns of growth rankings. 2We experimentally studied spatial and temporal patterns of species interactions and growth for three northern tree species: Larix laricina, Picea mariana and Pinus strobus. We compared species size and growth rankings over an 11-year period, for different species mixtures planted at four density levels in north-eastern Minnesota, USA. 3The benefits of different growth strategies changed with ontogeny and density leading to reversals in the size rank of competing species over time and space. High-density stands promoted dominance and resource pre-emption by L. laricina, whereas lower-density stands favoured gradual accumulation of biomass and eventual dominance by P. strobus. In the absence of strong neighbour competition, ontogenetic trends in growth had greater influence on growth patterns. 4Species interactions affected the productivity of mixed stands vs. monocultures. Species generally grew more in monoculture than when planted with P. strobus at low density, or with L. laricina at high density. Only L. laricina and P. mariana showed potential for greater overall productivity, or over-yielding, when planted together than alone, probably because of improved resource uptake by the highly stratified canopy. 5Synthesis. Density predictably determined whether size-asymmetric growth or ontogenetic growth trends would drive early establishment and growth patterns. Variation in vertical and horizontal structure that results from early competitive dynamics can influence the successional trajectory or character of the mature forest. This study extends previous efforts to identify the causes of rank reversals in communities and understand the importance of temporal changes beyond the early years of seedling establishment. [source] Comparative postnatal ontogeny of the skull in the australidelphian metatherian Dasyurus albopunctatus (Marsupialia: Dasyuromorpha: Dasyuridae)JOURNAL OF MORPHOLOGY, Issue 4 2006David A. Flores Abstract We describe the cranial ontogeny of an australidelphian marsupial, Dasyurus albopunctatus, using a combination of qualitative and quantitative approaches. We examined in detail qualitative morphological changes of just-weaned individuals as compared to old adults; specifically, changes in 31 morphological structures (e.g., processes, foramina) and 38 changes in cranial joints. We also interpreted growth-invariant structures in terms of their functional relevance. We performed a multivariate allometry analysis based on 14 cranial measurements taken from 31 specimens encompassing the entire postweaning period. Three variables (height of occipital plate, breadth of braincase, and height of mandible) showed the same allometric trends in D. albopunctatus and the three marsupial species studied previously in the same framework (Didelphis albiventris, Lutreolina crassicaudata, and Dromiciops gliroides). In addition, D. albopunctatus shared allometric trends in two variables (length of the upper postcanine row and length of the orbit) with the microbiotheriid D. gliroides. Most of the growth trends observed are interpreted as linked to the predominantly carnivorous dietary habit of adult D. albopunctatus. Because dasyuromorphians are most likely basal to the major Australasian radiation of marsupials, knowledge of ontogenetic changes in D. albopunctatus may shed light on the evolution of ontogeny in the highly diverse Australasian marsupial fauna. J. Morphol. © 2006 Wiley-Liss, Inc. [source] EMBEDDED CONTRASTS IN RACE, MUNICIPAL FRAGMENTATION, AND PLANNING: DIVERGENT OUTCOMES IN THE DETROIT AND GREATER TORONTO,HAMILTON REGIONS 1990,2000JOURNAL OF URBAN AFFAIRS, Issue 2 2009A. J. JACOBS ABSTRACT:,Since the early 1980s, scholars have debated whether or not the converging forces of globalization have disembedded city-regions from their national contexts. This study explored this question through a comparison of post-1990 growth trends in the Detroit and Greater Toronto Area,Hamilton regions (GTAH), two urban areas within the same natural region and closely linked by industrial production flows, yet politically situated within two separate Federalist states. Guided by Nested City Theory, it reveals how their dissimilar contexts for race, local autonomy, and multilocal planning have helped foster divergent spatial patterns in the two regions. In particular, provincial controls governing municipal fragmentation, Ontario's Planning Act, and subregional/microregional planning have been key embedded structures helping to limit population decline and disinvestment in GTAH core cities. In the process, this article shows how urban trajectories have remained nested within multilevel spatial and institutional configurations. Its findings also call for greater consideration of nested state/provincial factors in cross-national comparisons of cities within Federal states. Finally, its conclusion offers a starting point toward a more nuanced specific version of Nested Theory to be called the Contextualized Model of Urban,Regional Development. [source] Release of Juniperus thurifera woodlands from herbivore-mediated arrested succession in SpainAPPLIED VEGETATION SCIENCE, Issue 1 2010Lucía DeSoto Abstract Question: Do abiotic constraints maintain monospecific woodlands of Juniperus thurifera? What is the role of biotic (livestock) versus abiotic (climate) drivers in the recruitment and growth of the different tree species? Location: Cabrejas range, Soria, north-central Spain, 1200 m altitude. Methods: Stand history was reconstructed using dendro-ecology and spatial pattern analysis, combined with historical data of livestock abundances and climatic records. Results: J. thurifera establishment occurred in two distinct pulses, with a tree component establishing in the late 1800s to early 1900s. Quercus ilex and Pinus sylvestris establishment was evident only from the late 1970s onward. Recruitment events were related to reductions in livestock browsing. J. thurifera spatial structure was clumped and Q. ilex showed a short-scale aggregation to J. thurifera trees and saplings. Radial growth trends of J. thurifera saplings, Q. ilex and P. sylvestris were negatively related to livestock density. Summer drought limited the radial growth of all the study species, and P. sylvestris and Q. ilex grew faster than J. thurifera even after considering an age effect. Conclusions: The differences in radial growth patterns and recruitment pulses between species indicate that livestock browsing and not abiotic factors is the main factor controlling plant succession and structural development. In this process, J. thurifera acts as a nurse plant, facilitating the establishment of other tree species. Under the current low pressure from herbivores, formerly pure J. thurifera woodlands will change towards dense stands of mixed species composition. [source] Climatic signals in tree-rings of Araucaria angustifolia in the southern Brazilian highlandsAUSTRAL ECOLOGY, Issue 2 2010JULIANO MORALES OLIVEIRA Abstract Araucaria angustifolia (Bertol.) O. Kuntze (Araucariaceae) is a Neotropical tree, widely distributed in subtropical mountain rain forests and nearby natural grasslands of Southern Brazil. This species produces annual growth rings, but its dendroclimatic potential is barely known. In the present paper, the long-term growth patterns of A. angustifolia were investigated using annual growth ring time series and association to climate over the last century. Wood cores of A. angustifolia trees growing in forest and grassland habitats were obtained with an increment borer. The cores were surfaced, measured and cross-dated. The dated ring-width time series were standardized and submitted to correlation and principal component analysis to verify growth trends among sites and trees. Growth-climate relationships were investigated using correlation and regression analyses, comparing the ordination axes scores to regional time series of precipitation and temperature. Due to anatomical irregularities, mainly partial rings, only 35 out of 60 trees were cross-dated. The correlation and ordination analyses showed common tree-growth trends within and between sites, indicative of a regional environmental force determining inter-annual cambial activity variation. Despite growing in distinct habitats and disturbance regimes, A. angustifolia trees share a common long-term growth pattern, which is significantly related to thermal conditions during the current and previous growing seasons. Moreover, site-specific characteristics may have influenced opposite growth responses and association to climate conditions between forest and grassland trees. [source] | |||||||||||||