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Differential Growth (differential + growth)

Distribution by Scientific Domains

Life Sciences	55%
Humanities and Social Sciences	33%

Terms modified by Differential Growth

differential growth rate

Selected Abstracts

Differential growth and multicellular villi direct proepicardial translocation to the developing mouse heart

DEVELOPMENTAL DYNAMICS, Issue 1 2008
Laurel S. Rodgers
Abstract In the mammalian system the proepicardium (PE) arises from mesothelium of the septum transversum before translocation to the heart where it forms the epicardium and progenitor cells of the coronary vessels. Despite its importance, the process in which PE cells translocate to the myocardium in mammals is not well defined. The current paradigm states that cellular cysts of PE float across the pericardial space and contact the outer surface of the myocardium. This mechanism does not provide a satisfactory explanation for the directionality or localization of PE migration. To better define PE migration, we performed a detailed study of mouse PE development. We provide thorough documentation that redefines the size of the PE migratory field and the mechanism of migration. Our new model incorporates differential growth and direct contact between multicellular PE villi and the myocardium as mechanisms in formation of the epicardium. Developmental Dynamics 237:145,152, 2008. © 2007 Wiley-Liss, Inc. [source]

Forging Ahead and Falling Behind: Changing Regional Inequalities in Post-reform China

GROWTH AND CHANGE, Issue 1 2002
Max Lu
This study analyzes the evolution of China's regional inequalities during the reform period of 1978,1998 based on three geographical scales, both output and livelihood indicators of economic well-being and three measures of inequality. The results indicate that interprovincial and regional inequalities declined between 1978 and 1990, but have widened steadily since 1990. Urban-rural disparity diminished before 1984, then experienced a decade-long surge afterwards to peak in 1994 at a much higher level and since 1994, it has been declining again. The levels of regional inequalities in China appear to be sensitive to changes in government development strategies and regional policies. Differential growth of the provincial economies shaped by the coast-oriented and urban-biased development strategies as well as selective open-door policy implemented by the Chinese government after the reform is the key to understanding the wax and wane in China's regional inequalities. This paper discusses the factors that account for the changing regional inequalities in post-reform China and argues that government policies are likely to continue to influence the future trajectories of inequality change. [source]

Allometric studies on growth and development of the human placenta: growth of tissue compartments and diffusive conductances in relation to placental volume and fetal mass

JOURNAL OF ANATOMY, Issue 6 2006
Terry M. Mayhew
Abstract Correlations between placental size and fetal mass during gestation fail to account for changes in composition that accompany placental growth and maturation. This study uses stereological data on the sizes of different tissue compartments in human placentas from 10 weeks of gestation to term and relates them to placental volume and to fetal mass by means of allometric analysis. In addition, tissue dimensions are used to calculate a physiological transport measure (diffusive conductance) for the villous membrane. Histological sections randomly sampled from placentas and analysed stereologically provided estimates of structural quantities (volumes, exchange surface areas, lengths, numbers of nuclei, diffusion distances). These data were combined with a physicochemical quantity (Krogh's diffusion coefficient) in order to estimate oxygen diffusive conductances for the villous membrane and its two components (trophoblast and stroma). Allometric relationships between these quantities and placental volume or fetal mass were obtained by linear regression analyses after log-transformation. Placental tissues had different growth trajectories: most grew more rapidly than placental volume and all grew more slowly than fetal mass. Diffusion distances were inversely related to placental and fetal size. Differential growth impacted on diffusive conductances, which, again, did not improve commensurately with placental volume but did match exactly growth of the fetus. Findings show that successful integration between supply and demand can be achieved by differential tissue growth. Allometric analysis of results from recent studies on the murine placenta suggest further that diffusive conductances may also be matched to fetal mass during gestation and to fetal mass at term across species. [source]

Differential growth and multicellular villi direct proepicardial translocation to the developing mouse heart

The Creation of a Distinct Subcultural Identity and Denominational Growth

JOURNAL FOR THE SCIENTIFIC STUDY OF RELIGION, Issue 3 2003
John H. Evans
Scholars have long been concerned with the causes of differential growth in the membership of religious traditions and denominations. In this article I use data from three surveys, matched with census and membership data from U.S. states, to test Smith's recent theory of denominational growth and decline. I find that in the one denomination under study, the Presbyterian Church (USA), the states where membership has declined the least are those states where the members of the denomination are both the most theologically orthodox and have the strongest identity as theological liberals. Although seemingly paradoxical, it fits Smith's theory well. Liberal Protestants do not thrive where they are the most conservative, but rather where they have created a unique identity,a unique social niche,somewhere between evangelicalism and secularism. [source]

Glycoconjugates in the otolithic membrane of herring larvae: a possible framework for encoding the life history recorder in fishes

JOURNAL OF FISH BIOLOGY, Issue 1 2002
P. Tytler
Glycoconjugates in the inner ear of herring Clupea harengus larvae, investigated by laser confocal and electron microscopy, were located mainly in the gelatinous layer of the otolithic membranes, forming a collar around the proximal surfaces of the otoliths. The site of secretion was located on the surface of the sensory macula, from which a colonnade of glycoconjugate streamers projected through the subcupular region to connect with the gelatinous layer of each otolith. An electron dense component of the outer gelatinous layers, shown by TEM to be closely associated with the sensory kinocilia, suggested that they provided a basis for the streamers and offered a potential role in directing the path of secretion. It is hypothesized that this highly structured glycoconjugate framework could provide a mechanism for localizing and containing ionic and protein gradients previously detected in this vicinity and which are considered to have a key role in driving the differential growth and mineralization of the otoliths. [source]

Changes in mitogen-activated protein kinase activity occur in the maize pulvinus in response to gravistimulation and are important for the bending response

PLANT CELL & ENVIRONMENT, Issue 7 2003
A. M. CLORE
ABSTRACT The maize (Zea mays L.) pulvinus was used as a model system to study the signalling events that lead to differential growth in response to gravistimulation in plants. The pulvinus functions to return tipped plants to vertical via differential elongation of the cells on its lower side. By performing immunokinase assays using total soluble protein extracts and an antibody against mammalian ERK1, a mitogen-activated protein kinase (MAPK)-like activity was assayed in pulvini halves harvested at various time points after tipping. We detected a reproducible alternation of higher levels of activity occurring between the upper and lower halves of the pulvinus between 75 and 180 min after tipping, with a sustained increase in the upper half occurring at the end of the time-course. This timing roughly corresponds to the presentation time for maize (i.e. the amount of time that the plant needs to be tipped before it is committed to bend), which occurs between 2 and 4 h. Treatment of maize stem explants with an inhibitor of MAPK activation, U0126, led to a reduction in the activity of this kinase, as well as an almost 65% reduction in bending as measured at 20 h. Rinsing out of the inhibitor resulted in recovery of both bending and kinase activity. It is possible that changes in MAPK activity in the gravistimulated pulvinus are part of a signalling cascade that may help to distinguish between minor perturbations in plant orientation and more significant and long-term changes, and may also help to determine the direction of bending. [source]

Age- and site-specific decline in insulin-like growth factor-I receptor expression is correlated with differential growth plate activity in the mouse hindlimb

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 4 2007
Maria A. Serrat
Abstract The proximal and distal growth plates of the principal long bones do not contribute equally to longitudinal growth. Most forelimb elongation occurs at the shoulder and wrist, while most hindlimb growth occurs at the knee. This study examined whether insulin-like growth factor-I (IGF-I), a potent growth regulator, could underlie this variation via differential receptor expression. The spatiotemporal distribution of the IGF-I receptor (IGF-IR) was mapped in hindlimb growth plates (overall and within regional zones) from immature mice using immunohistochemistry. Growth activity was assessed by size/morphology of the growth plate and proliferating cell nuclear antigen (PCNA) expression. Both IGF-IR and PCNA staining declined considerably with age in the proximal femur and distal tibia (hip and ankle), but expression remained high in the more active distal femur and proximal tibia (knee) throughout growth. Growth plate size decreased with age in all sites, but the absolute and relative decline in IGF-IR in the hips and ankles of older mice indicated a site-specific loss of IGF-I sensitivity in these less active regions. These results suggest that regulation of the IGF-IR may at least partially mediate differential long bone growth, thereby providing a local mechanism for altering skeletal proportions absent modification of systemic hormone levels. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source]

Staple theory and export-led growth: constructing differential growth

AUSTRALIAN ECONOMIC HISTORY REVIEW, Issue 3 2003
Morris Altman
The staple theory is a subset of the export-led growth hypothesis, designed to explain the growth and economic development of resource-rich economies. It is a theory that has been misunderstood and is seen to be at odds with the stylised facts of economic growth and development as well as with mainstream neoclassical wisdom. This article presents a brief and critical historiography of the staple theory from which a simple model of staple growth and development is gleaned. As well, data are presented which suggest that staple theory remains an important analytical tool to help explain economic development and growth. [source]