Growth curve of the lichen Rhizocarpon geographicum

Data on the growth curve of the lichen Rhizocarpon geographicum were obtained by measuring the radial growth rates (mm per 1.5 years) of 39 thalli from 2 to 65 mm in diameter growing in the same environment. An Aplin and Hill plot (r2 – r1 against ln r2 – ln r1) of the data and regression analyses suggested an initial phase of growth (up to a diameter of about 7 mm) in which the relative growth rate increased rapidly. This was followed by a phase in which the relative growth rate fell but the radial growth rate continued to rise (7 to 20 mm in diameter). Radial growth was then relatively constant until about 45 mm diameter and then declined. The Aplin and Hill model did not fit the data as a whole but may apply for a transient period in thalli between about 7 and 16 mm in diameter. The curve shows some similarities to that suggested by lichenometric studies but differs in showing a less steep decline in growth rate after the ‘great’ period.

Growth phases in the life of a lichen thallus

The growth rates of thalli of foliose saxicolous lichens before and after the linear phase of growth were measured in 1973. Changes in the radial growth rate (measured as mm/year) with thallus size in the prelinear phase (thalli less than approximately 1.5 cm in diameter) were consistent with the hypothesis that early growth of these lichens is loagarithmic. When growth in the prelinear phase was measured as a relative growth rate (measured as sq cm/sq cm/year) there was a rapid rise in growth rate until about 3 mm thallus diameter and then a decline in growth rate. The radial growth rate of non-fragmenting thalli when compared with fragmenting thalli at different stages of fragmentation suggested that radial growth rate does not significantly decline after fragmentation of the thallus. This result is not consistent with a postlinear phase in the radial growth of a lichen thallus.

The influence of environmental factors on the growth of lichens in the field

The majority of studies of the effects of environmental factors on lichen growth have been carried out in the field. Growth of lichens in the field has been measured as absolute growth rate (e.g., length growth, radial growth, diameter growth, area growth, or dry weight gain per unit of time) or as a relative growth rate, expressed per unit of thallus area or weight, e.g., thallus specific weight. Seasonal fluctuations in growth in the field often correlate best with changes in average or total rainfall or frequency of rain events through the year. In some regions of the world, temperature is also an important climatic factor influencing growth. Interactions between microclimatic factors such as light intensity, temperature, and moisture are particularly important in determining local differences in growth especially in relation to aspect and slope of rock surface, or height on a tree. Factors associated with the substratum including type, chemistry, texture, and porosity can all influence growth. In addition, growth can be influenced by the degree of nutrient enrichment of the substratum associated with bird droppings, nitrogen, phosphate, salinity, or pollution. Effects of environmental factors on growth can act directly to restrict species distribution or indirectly by altering the competitive balance among different species in a community.

Systematic microcarrier screening and agitated culture conditions improves human mesenchymal stem cell yield in bioreactors

Production of human mesenchymal stem cells for allogeneic cell therapies requires scalable, cost-effective manufacturing processes. Microcarriers enable the culture of anchorage-dependent cells in stirred-tank bioreactors. However, no robust, transferable methodology for microcarrier selection exists, with studies providing little or no reason explaining why a microcarrier was employed. We systematically evaluated 13 microcarriers for human bone marrow-derived MSC (hBM-MSCs) expansion from three donors to establish a reproducible and transferable methodology for microcarrier selection. Monolayer studies demonstrated input cell line variability with respect to growth kinetics and metabolite flux. HBM-MSC1 underwent more cumulative population doublings over three passages in comparison to hBM-MSC2 and hBM-MSC3. In 100 mL spinner flasks, agitated conditions were significantly better than static conditions, irrespective of donor, and relative microcarrier performance was identical where the same microcarriers outperformed others with respect to growth kinetics and metabolite flux. Relative growth kinetics between donor cells on the microcarriers were the same as the monolayer study. Plastic microcarriers were selected as the optimal microcarrier for hBM-MSC expansion. HBM-MSCs were successfully harvested and characterised, demonstrating hBM-MSC immunophenotype and differentiation capacity. This approach provides a systematic method for microcarrier selection, and the findings identify potentially significant bioprocessing implications for microcarrier-based allogeneic cell therapy manufacture. Large-scale production of human bone-marrow derived mesenchymal stem cells (hBM-MSCs) requires expansion on microcarriers in agitated systems. This study demonstrates the importance of microcarrier selection and presents a systematic methodology for selection of an optimal microcarrier. The study also highlights the impact of an agitated culture environment in comparison to a static system, resulting in a significantly higher hBM-MSC yield under agitated conditions.

The comparative impact of privatisation and regulation on productivity growth in the English and Welsh water and sewerage industry, 1985-99

After the 10 regional water authorities of England and Wales were privatized in November 1989, the successor WASCs (water and sewerage companies) faced a new regulatory regime that was designed to promote productivity growth while simultaneously improving drinking water and environmental quality. As legally mandated quality improvements necessitated a costly capital investment programme, the industry's economic regulator – the Office of Water Services – implemented a RPI + K pricing system, designed to compensate the WASCs for their capital investment programme while also encouraging faster rates of productivity growth. This paper considers the relative effects of privatization and regulation on productivity growth in the industry using both non-parametric and parametric methods to provide a crosscheck on the robustness of the results. While there is evidence that labour productivity improved after privatization, there is no evidence that privatization led to a growth in TFP (total factor productivity). However, there is some evidence of a small increase in the rate of TFP growth in the aftermath of a substantial tightening of the regulatory regime that took place in 1995. These results, therefore, are consistent with evidence from other research that privatization, in the absence of effective competition and/or regulation, is not necessarily associated with improved economic performance.

The influence of serum, glucose and oxygen on intervertebral disc cell growth in vitro:implications for degenerative disc disease

The avascular nature of the human intervertebral disc (IVD) is thought to play a major role in disc pathophysiology by limiting nutrient supply to resident IVD cells. In the human IVD, the central IVD cells at maturity are normally chondrocytic in phenotype. However, abnormal cell phenotypes have been associated with degenerative disc diseases, including cell proliferation and cluster formation, cell death, stellate morphologies, and cell senescence. Therefore, we have examined the relative influence of possible blood-borne factors on the growth characteristics of IVD cells in vitro.

Factors determining lobe growth in foliose lichen thalli

This study investigates the relative importance of climate, lobe morphology and lobe interactions in determining the radial growth of individual lobes in foliose lichen thalli. The radial growth of 75 lobes from thalli of Parmelia conspersa (Ehrh. Ex Ach.) Ach. and Parmelia glabratula ssp. fuliginosa (Fr. ex Duby) Laund. was measured over 22 successive months in relation to climatic factors. Individual lobes showed a fluctuating pattern of radial growth with alternating periods of fast and slow growth. In 17/75 (23%) of lobes studied, monthly radial growth was correlated with a climatic factor, usually total rainfall or the frequency of sunshine hours. In addition, the radial growth of 54 lobes of P. conspersa was measured over four months in relation to lobe morphology and the radial growth and morphology of adjacent lobes. Radial growth was correlated with lobe length and with the radial growth of adjacent lobes. In addition, the pattern of lobe branching appeared to be related to lobe width and to a lesser extent to lobe length and the width of adjacent lobes. The radial growth in one year of exceptionally long lobes which had grown beyond the thallus margin was similar to more normal lobes, but experimentally bisected lobes had significantly reduced radial growth compared with control lobes. These results suggested that the fluctuating pattern of radial growth in individual lobes may be determined by climate and the pattern of lobe branching. In addition, the pattern of lobe branching was related to lobe width and may be influenced by adjacent lobes.

Iron in the substrates and sporophores of Agaricus bisporus (Lange) Pilat during growth and development

The changes of the concentration of iron in the growth substrates and the sporophores of Agaricus bisporus (Lange) Pilat that occurred during culture under standard commercial conditions, were observed using atomic absorption spectrophotometry and iron-59 radiotracing techniques. The routes of translocation and sites of iron accumulation within the sporophore were shovn to alter during development and by the use of novel, pelletised substrates the concentration of iron in the mycelium of the substrates and in developing sporophores was observed during culture. Findings indicated that the compost was the major source of iron and that the concentration of iron in the compost mycelium varied cyclically in relation to the periodic appearance of sporophores. In the casing layer the mycelium is organised into strands which are responsible for the movement of iron from the compost into developing sporophores. A photographic technique for estimating sporophore growth rates showed that the accumulation of iron was not concomitant with sporophore growth and this was attributable to a declining quantity of available iron in the compost mycelium during sporophore growth. Variations in the quantity of iron in sporophores resulted primarily from differences in the quantity of water soluble iron in the compost but, the productivity of the crop, the type of casing layer and differences in watering also influenced sporophore composition. Changes in the concentration of extractable iron in the compost and casing layer throughout culture were related to mycelial activity and to a lesser extent were influenced by watering and the bacterial populations of the casing layer. Thus, the findings of this study give some indication of the relative importance that different cultural conditions exert over sporophore composition together with demonstrations of the movement of a single material within the sporophores and substrates during the cultivation of Agaricus bisporus.

Openness and economic growth

The themes of this thesis are that international trade and foreign direct investment (FDI) are closely related and that they have varying impacts on economic growth in countries at different stages of development. The thesis consists of three empirical studies. The first one examines the causal relationship between FDI and trade in China. The empirical study is based on a panel of bilateral data for China and 19 home countries/regions over the period 1984-98. The specific feature of the study is that econometric techniques designed specially for panel data are applied to test for unit roots and causality. The results indicate a virtuous procedure of development for China. The growth of China’s imports causes growth in inward FDI from a home country/region, which in turn causes the growth of exports from China to the home country/region. The growth of exports causes the growth of imports. This virtuous procedure is the result of China’s policy of opening to the outside world. China has been encouraging export-oriented FDI and reducing trade barriers. Such policy instruments should be further encouraged in order to enhance economic growth. In the second study, an extended gravity model is constructed to identify the main causes of recent trade growth in OECD countries. The specific features include (a) the explicit introduction of R&D and FDI as two important explanatory variables into an augmented gravity equation; (b) the adoption of a panel data approach, and (c) the careful treatment of endogeneity. The main findings are that the levels and similarities of market size, domestic R&D stock and inward FDI stock are positively related to the volume of bilateral trade, while the geographical distance, exchange rate and relative factor endowments, has a negative impact. These findings lend support to new trade, FDI and economic growth theories. The third study evaluates the impact of openness on growth in different country groups. This research distinguishes itself from many existing studies in three aspects: first, both trade and FDI are included in the measurement of openness. Second, countries are divided' into three groups according to their development stages to compare the roles of FDI and trade in different groups. Third, the possible problems of endogeneity and multicollinearity of FDI and trade are carefully dealt with in a panel data setting. The main findings are that FDI and trade are both beneficial to a country's development. However, trade has positive effects on growth in all country groups but FDI has positive effects on growth only in the country groups which have had moderate development. The findings suggest FDI and trade may affect growth under different conditions.

The measurement and decomposition of economy-wide productivity growth:Assessing the accuracy and selecting between different approaches

Productivity at the macro level is a complex concept but also arguably the most appropriate measure of economic welfare. Currently, there is limited research available on the various approaches that can be used to measure it and especially on the relative accuracy of said approaches. This thesis has two main objectives: firstly, to detail some of the most common productivity measurement approaches and assess their accuracy under a number of conditions and secondly, to present an up-to-date application of productivity measurement and provide some guidance on selecting between sometimes conflicting productivity estimates. With regards to the first objective, the thesis provides a discussion on the issues specific to macro-level productivity measurement and on the strengths and weaknesses of the three main types of approaches available, namely index-number approaches (represented by Growth Accounting), non-parametric distance functions (DEA-based Malmquist indices) and parametric production functions (COLS- and SFA-based Malmquist indices). The accuracy of these approaches is assessed through simulation analysis, which provided some interesting findings. Probably the most important were that deterministic approaches are quite accurate even when the data is moderately noisy, that no approaches were accurate when noise was more extensive, that functional form misspecification has a severe negative effect in the accuracy of the parametric approaches and finally that increased volatility in inputs and prices from one period to the next adversely affects all approaches examined. The application was based on the EU KLEMS (2008) dataset and revealed that the different approaches do in fact result in different productivity change estimates, at least for some of the countries assessed. To assist researchers in selecting between conflicting estimates, a new, three step selection framework is proposed, based on findings of simulation analyses and established diagnostics/indicators. An application of this framework is also provided, based on the EU KLEMS dataset.

Impact of FDI, ODA and migrant remittances on economic growth in developing countries:a systems approach

This article seeks to investigate the relative contributions of foreign direct investment, official development assistance and migrant remittances to economic growth in developing countries. We use a systems methodology to account for the inherent endogeneities in these relationships. In addition, we also examine the importance of institutions, not only for growth directly, but for the interactions between institutions and the other sources of growth. It is, we believe, the first article to consider each of these variables together. We find that all sources of foreign capital have a positive and significant impact on growth when institutions are taken into account. © 2013 European Association of Development Research and Training Institutes.

Elevated placental soluble vascular endothelial growth factor receptor-1 inhibits angiogenesis in preeclampsia

Preeclampsia is an inflammatory disorder in which serum levels of vascular endothelial growth factor (VEGF) and its soluble receptor-1 (sVEGFR-1, also known as sFlt-1) are elevated. We hypothesize that VEGF and placenta growth factor (PlGF) are dysregulated in preeclampsia due to high levels of sVEGFR-1, which leads to impaired placental angiogenesis. Analysis of supernatants taken from preeclamptic placental villous explants showed a four-fold increase in sVEGFR-1 than normal pregnancies, suggesting that villous explants in vitro retain a hypoxia memory reflecting long-term fetal programming. The relative ratios of VEGF to sVEGFR-1and PlGF to sVEGFR-1 released from explants decreased by 53% and 70%, respectively, in preeclampsia compared with normal pregnancies. Exposure of normal villous explants to hypoxia increased sVEGFR-1 release compared with tissue normoxia (P<0.001), as did stimulation with tumor necrosis factor-α (P<0.01). Conditioned medium (CM) from normal villous explants induced endothelial cell migration and in vitro tube formation, which were both attenuated by pre-incubation with exogenous sVEGFR-1 (P<0.001). In contrast, endothelial cells treated with preeclamptic CM showed substantially reduced angiogenesis compared withnormal CM (P<0.001), which was not further decreased by the addition of exogenous sVEGFR-1, indicating a saturation of the soluble receptor.Removal of sVEGFR-1 by immunoprecipitation from preeclamptic CM significantly restored migration (P<0.001) and tube formation (P<0.001) to levels comparable to that induced by normal CM, demonstrating that elevated levels of sVEGFR-1 in preeclampsia are responsible for inhibiting angiogenesis. Our finding demonstrates the dysregulation of the VEGF/PlGF axis in preeclampsiaand offers an entirely new therapeutic approach to its treatment.

Productivity growth and efficiency measurements in fuzzy environments with an application to health care

Health care organizations must continuously improve their productivity to sustain long-term growth and profitability. Sustainable productivity performance is mostly assumed to be a natural outcome of successful health care management. Data envelopment analysis (DEA) is a popular mathematical programming method for comparing the inputs and outputs of a set of homogenous decision making units (DMUs) by evaluating their relative efficiency. The Malmquist productivity index (MPI) is widely used for productivity analysis by relying on constructing a best practice frontier and calculating the relative performance of a DMU for different time periods. The conventional DEA requires accurate and crisp data to calculate the MPI. However, the real-world data are often imprecise and vague. In this study, the authors propose a novel productivity measurement approach in fuzzy environments with MPI. An application of the proposed approach in health care is presented to demonstrate the simplicity and efficacy of the procedures and algorithms in a hospital efficiency study conducted for a State Office of Inspector General in the United States. © 2012, IGI Global.

Regional competitiveness, economic growth and stages of development

This paper positions the concept of regional competitiveness within theories concerning regional economic growth and stages of economic development. It examines the sources of regional competitiveness encompassing an analysis based on the particular stage of economic development that the nations within which regions are situated have reached. As a means to achieve this, the paper undertakes an empirical analysis of data stemming from the World Competitiveness Index of Regions, and identifies regional competitiveness as a dual concept that explains relative differences in rates of economic development across regions, as well as an understanding of the future economic growth trajectories of regions at a similar stage of economic development. As with endogenous growth and development theory, the notion of regional competitiveness presented here places knowledge, innovation and entrepreneurship at the forefront of conceptualisations of regional economic differentiation.

The relative advantage of marketing over technological capabilities in influencing new product performance:the moderating role of country institutions

Marketing and technological capabilities are major drivers of new product performance. Prior research has suggested that marketing capabilities outperform technological capabilities. This study shows that the relative advantage of marketing over technological capabilities for new product performance depends on the institutional context in a country. Meta-analytic data of 341 effect sizes of the relationship between capabilities and new product performance taken from 50 articles with 57 independent samples and collected in 17 different countries reveal new contingencies to the capabilities framework. Although in general, marketing capabilities have a stronger influence than technological capabilities on new product performance, this effect is moderated by institutional context factors. The relative advantage decreases and even reverses with increasing growth rates; it further decreases with increasingly stronger rules of law in a country; and it increases in societies that put emphasis on self-expression values over survival values. These findings contribute to research on the utility of different capabilities, inform the institution-based view of firms in international marketing, and provide implications for international marketing managers.