24 research outputs found
Migratory chondrogenic progenitor cells from repair tissue during the later stages of human osteoarthritis.
No full textSummaryThe regeneration of diseased hyaline cartilage continues to be a great challenge, mainly because degeneration—caused either by major injury or by age-related processes—can overextend the tissue's self-renewal capacity. We show that repair tissue from human articular cartilage during the late stages of osteoarthritis harbors a unique progenitor cell population, termed chondrogenic progenitor cells (CPCs). These exhibit stem cell characteristics such as clonogenicity, multipotency, and migratory activity. The isolated CPCs, which exhibit a high chondrogenic potential, were shown to populate diseased tissue ex vivo. Moreover, downregulation of the osteogenic transcription factor runx-2 enhanced the expression of the chondrogenic transcription factor sox-9. This, in turn, increased the matrix synthesis potential of the CPCs without altering their migratory capacity. Our results offer new insights into the biology of progenitor cells in the context of diseased cartilage tissue. Our work may be relevant in the development of novel therapeutics for the later stages of osteoarthritis
The ability for migration and proliferation ex vivo of human chondrogenic progenitor cells from late stages of osteoarthritis and the effects of in vitro culture on gene-expression
No full textDiese Arbeit untersucht die humanen chondrogenen Progenitorzellen (CPC) auf ihre Eignung für einen möglichen Therapieansatz der Osteoarthrose (OA). Hierbei zeigte sich, dass die CPC die Fähigkeit zur Migration sowohl in vitro als auch ex vivo besitzen. In vitro steigerte der Einsatz von TGF-ß3 die Migrationsrate, was von therapeutischem Nutzen sein könnte. Die CPC wanderten ex vivo ebenso in Knorpelgewebe aus makroskopisch unauffälligen Bereichen wie in an den Hauptdefekt angrenzendes Gewebe ein. Mit der Versuchsdauer nahm die Einwanderungstiefe zu, wobei dies im unauffällig erscheinenden Knorpel ausgeprägter war und hier auch größere Eindringtiefen gemessen wurden. Dies spricht für eine Zielzone, die die CPC anstreben und die im Knorpel neben dem Hauptdefekt früher erreicht wird. Bezüglich der Migrationsgeschwindigkeit weisen die CPC eine Heterogenität auf, verglichen mit anderen Zelltypen im menschlichen Organismus ist sie insgesamt allerdings gering. Über die gesamte Versuchsdauer ließen sich in beiden Gewebetypen proliferationsfähige CPC nachweisen. Eine Genexpressionsanalyse zeigte, dass die CPC dedifferenzierten Chondrozyten am ähnlichsten sind und eine kurzfristige Kultivierung sie kaum beeinflusst. Die Transfektion veränderte die Ausrichtung der CPC nicht, sondern führte vornehmlich zu einer vorübergehenden generellen Herabregulierung der Genexpression. Die Ergebnisse zeigen, dass ein therapeutischer Einsatz der CPC möglich wäre, da die Zellen auf einfache und komplikationsarme Weise gewonnen und kultiviert werden können. Zudem eröffnen die ausgeprägten migratorischen Fähigkeiten der CPC einfache Applikationswege, z. B. im Rahmen einer intraartikulären Injektion oder Arthroskopie. Ebenso viel versprechend ist die Erkenntnis, dass die Zellen innerhalb des Gewebes vital bleiben und so an einer Regeneration teilhaben könnten. Vor einer zukünftigen Anwendung der CPC bleiben allerdings noch einige Fragen zu beantworten. So ist die Rolle der CPC in der Pathogenese der OA noch nicht vollständig geklärt. Außerdem bleibt offen, wie lange die CPC im Gewebe vital bleiben und ob sie in der Lage sind, im Gewebe hyaline Knorpel-EZM herzustellen. Die Ergebnisse dieser Arbeit geben daher Anlass für weitere Forschung auf diesem Gebiet.This study shows the ability for migration and proliferation ex vivo of human chondrogenic progentior cells (CPC) from late stages of osteoarthritis. It also shows that short-time in vitro culture has only small effects on their gene-expression-pattern. These results may be relevant in the development of novel therapeutics for the later stages of osteoarthritis.2015-05-2
Model selection for monetary policy analysis – Importance of empirical validity
No full textWe investigate the importance of employing a valid model for monetary policy analysis. Specifically, we investigate the economic significance of differences in specification and empirical validity of models. We consider three alternative econometric models of wage and price inflation in Norway. We find that differences in model specification as well as in parameter estimates across models can lead to widely different policy recommendations. We also find that the potential loss from basing monetary policy on a model that may be invalid, or on a suite of models, even when it contains the valid model, can be substantial, also when gradualism is exercised as a concession to model uncertainty. Furthermore, possible losses from such a practice appear to be greater than possible losses from failing to choose the optimal policy horizon to a shock within the framework of a valid model. Our results substantiate the view that a model for policy analysis should necessarily be empirically valid and caution against compromising this property for other desirable model properties, including robustness.Model uncertainty; Econometric modelling; Economic significance; Robust monetary policy.
Dreamers of the Dark: Kerry Bolton and the Order of the Left Hand Path, a Case-study of a Satanic/Neo-Nazi Synthesis
No full textIn 1990 a small self-published journal/magazine called The Watcher was distributed among New Zealand's occult underground. The Watcher described itself as 'the New Zealand Voice of the Left Hand Path', and was published as the journal of the Order of the Left Hand Path. The Watcher and the Order directed its attentions towards those occultists who identified themselves as Satanists and, as such, the journal articulated a distinctly Satanic philosophy and perspective. However, as the journal evolved and developed, renaming itself as The Heretic and The Nexus in later years, there arose alongside Satanic philosophy an increasing emphases on what could be called esoteric Nazism or esoteric Nationalism. Given that the editor of The Watcher was Kerry Bolton, a man who has been immersed in New Zealand's Nationalist/neo-Nazi movement since the early 1970s, such an increasingly political orientation was perhaps unsurprising.
This thesis examines the way in which the Order bought Satanic and neo-Nazi ideologies together and the resulting synthesis. It also looks at the transition from being a Satanic order led by a neo-Nazi to an openly neo-Nazi Order that uses Satanic philosophy to justify and popularise its conception of National Socialism
Causal Parameters and Policy Analysis in Economcs: A Twentieth Century Retrospective
No full textThe major contributions of twentieth century econometrics to knowledge were the definition of causal parameters when agents are constrained by resources and markets and causes are interrelated, the analysis of what is required to recover causal parameters from data (the identification problem), and clarification of the role of causal parameters in policy evaluation and in forecasting the effects of policies never previously experienced. This paper summarizes the development of those ideas by the Cowles Commission, the response to their work by structural econometricians and VAR econometricians, and the response to structural and VAR econometrics by calibrators, advocates of natural and social experiments, and by nonparametric econometricians and statisticians.
Analysis of the expected error performance of cooperative wireless networks employing distributed space-time codes
No full textIn this paper, typical uplink scenarios in a cellular system are considered, where two cooperating mobile stations (serving, for example, as mobile relays) are transmitting the same information to a base station by using a distributed space-time coding scheme. Due to the distributed nature of the system, the transmitted signals are typically subject to different average path losses. For fixed distances between the mobile stations and the base station, the error performance of the distributed space-time coding scheme is determined analytically. Then, based on considerations concerning the spatial distribution of the mobile stations, analytical expressions for the distribution of the average path losses are derived and verified by means of simulations. These results are then used in order to compute the expected error performance of the system. It is shown that in most scenarios the average performance loss compared to a conventional multiple-antenna system with colocated antennas is less than 2 dB at a bit error rate of 10(-3). The most significant performance losses occur for a large path-loss exponent.</p
"Revenue management"effects related to financial flows generated by climate policy
No full textThis paper discusses possible macroeconomic implications for low-income countries of increased revenue inflows that may follow from implementing certain global greenhouse gas mitigation policies. Such revenue sources include revenue from emissions offset mechanisms, direct investments, and financial transfers that form parts of possible future mitigation treaties. In the short run such revenue will come mainly from offset markets and donor-sponsored programs, with some additional financial inflows due to foreign direct investments. In the longer run, comprehensive global cap-and-trade or carbon tax schemes could provide a potentially much larger revenue flow to many low-income countries. The author argues that the macroeconomic implications of such flows are manageable in the short run, but the larger revenues resulting from global emissions schemes could overwhelm this capacity and lead to a number of potential macroeconomic management problems.Debt Markets,Climate Change Economics,Emerging Markets,Economic Theory&Research,Access to Finance
Exploiting Energy and Mineral Resources in Central Asia, Azerbaijan and Mongolia
No full textRecent literature has focussed on institutional degradation and revenue volatility as major sources of a resource curse. Formerly centrally planned countries may be especially vulnerable due to their mutating institutions and macropolicy inexperience. This paper examines these issues through case studies of six former Soviet republics and Mongolia. The principal focus is on the methods of involving foreign partners in exploration and exploitation of natural resources and, to a lesser extent, on the use of revenues during resource booms. The consequences of alternative resource ownership patterns are difficult to model due to path dependency and the significance of the conjuncture of circumstances. Kazakhstan in the 1990s was a prime example of rent-seeking institutional degradation, but an exceptionally positive conjuncture in the 2000s (soaring oil prices, large oil and gas discoveries, and new pipelines) triggered institutional and policy evolution. Uzbekistan, by contrast, had less resource-rent-driven institutional degradation in the 1990s, but stagnated in the 2000s. Turkmenistan and Mongolia highlight the missed opportunities from not involving foreign partners, while Azerbaijan and the Kyrgyz Republic illustrate the less predictable outcomes following quick deals with foreign investors. Institutions matter, but the case studies suggest more complex relationships than revealed by simple correlations between indicators of institutional quality or of ownership patterns.oil, gas, minerals, Central Asia, resource curse
The Time-to-Build Tradition in Business Cycle Modelling
No full textAn important frontier of business cycle theorising is the 'time-to-build' tradition that lies at the heart of Real Business Cycle theory. Kydland and Prescott (1982) did not acknowledge the rich tradition of 'time-to-build' business cycle theorising - except in a passing, non-scholarly, non-specific, reference to Böhm-Bawerk's classic on Capital Theory (Böhm-Bawerk [1899]), which did not, in any case, address cycle theoretic issues. The notion of ‘time-to-build’ is intrinsic to any process oriented production theory which is incorporated in a macrodynamic model. We provide an overview of this tradition, focusing on some of the central business cycle classics, and suggest that the Neo-Austrian revival should be placed in this class of dynamic macroeconomics, albeit ‘traverse dynamics’ is itself to be considered as a fluctuating path from one equilibrium to another.
Public procurement as an industrial policy tool an option for developing countries?
No full textSo far, only 40 countries have joined WTOÿs Government Procurement Agreement (GPA), from the developing world only some East Asian (Hong Kong [China], South Korea, Singapore) economies and ten Eastern European countries are parties to the agreement. This article sets out to answer two interrelated questions: is it advisable for developing countries to use public procurement efforts for development, and should more developing countries join the GPA? We survey key arguments for and against joining the GPA, and by adopting the framework of public procurement for innovation, we argue that government procurement should not be seen only as an indirect support measure for development, but also as a direct vehicle for promoting innovation and industries and, thus, growth and development. We also show that using public procurement for development assumes high levels of policy capacity, which most developing countries lack. In addition, we show how the GPA as well as other WTO agreements make it complicated for the developing countries to benefit from public procurement for innovation. As a result, the article suggests that the developing countries could apply a mix of direct and indirect (so-called soft) publicprocurement- for-innovation measures. In order to do this, developing countries need to develop the policy capacity to take advantage of the complex and multi-layered industrial policy space still available under WTO rules.
