environmental policy vs public pressure innovation and diffusion of alternative bleaching technologies in the pulp industry abstract in the late 1980s and early 1990s concern over dioxin in both paper products and wastewater led to the development of techniques that reduced the use of chlorine in the pulp industry both regulatory and consumer pressure motivated this change unlike previous studies we use patent data to examine the evolution of two competing bleaching technologies in five major paper producing countries both of which reduce the use of chlorine in the pulping process the use of patent data allows us to focus on the invention stage however adoption data are also presented and by the end of the 1990s nearly all pulp production in these countries used one of these technologies while previous studies emphasize the importance of regulation for inducing innovation here we find substantial innovation occurring before regulations were in place instead pressure from consumers and the public at large to reduce the chlorine content of paper drove invention prior to the introduction of environmental policies in any of the countries concerned

the empirical analysis of the determinants for environmental technological change a research agenda abstract technological change is usually considered a necessary albeit not sufficient condition for a transition to sustainability however the empirical analysis of the determinants to environmental technological change has not received too much attention in the environmental ecological economics literature and many open questions remain in this context based on a careful review of the literature this paper argues that further analysis should address several issues at different levels i e regarding the conceptual framework the thematic scope of the studies some methodological issues and other aspects related to the environmental policy variable first an integrated conceptual framework which takes into account the interplay between relevant variables influencing environmental technological change i e factors internal and external to the firm and characteristics of the environmental technologies and all the stages of this process with a greater emphasis on the invention stage should be developed other aspects should then be tackled including a focus on several themes i e a greater attention to cross sectoral technologies the barriers to different types of environmental technologies the international dimension of environmental technological change and environmental technological change in small and medium size enterprises methodological issues combination of case studies and econometric modelling and several issues related to the environmental policy variable

a portfolio approach to endogenous growth equilibrium and optimal policy abstract this paper develops a portfolio approach to modeling endogenous growth in continuous time that is especially suitable for addressing fiscal and financial issues in policy design the analysis focuses on the equilibrium relationship between fiscal and financial policy rates of return and wealth allocation we analyze two models the first is based on the arrow romer model with increasing returns and an external effect of capital on labor productivity the second draws on barro s analysis of government spending and endogenous growth in both models we study the equilibrium allocation and discuss the optimal fiscal and financial policy

which way does water flow an econometric analysis of the global price integration of water stocks around us 600 billion of investment is desperately needed to address forecasted huge shortages in water supply globally a number of worldwide investors so called water funds have started to take up this challenge for these global water investors knowledge about the extent of integration between the water sectors of financial markets is highly important according to international portfolio diversification theory the less more integrated markets are the more less benefits there are from international diversification in this study we investigate the extent and manner of interdependence among the us european and asian water sector of the equity markets based on vector autoregression var granger causality and impulse response analyses we find that world water stock market prices are indeed significantly interdependent although this interdependence varies across time periods each market quickly responds to shocks from each other and completes its response within 3 days hence for water in

an investigation into the interdependence of global water indices a var analysis we investigate the extent and manner of equity price interdependence among four water indices world water index s network global water index s net s p global water index s p and msci acwi water utilities index msci acwi using the vector autoregression var framework for the period 2004 2014 we also employ methods of granger causalities variance decomposition and impulse responses we find granger causality significance between s net and msci acwi and s net and s p indices at the 1 level of significance suggesting that the indices are significantly linked further s net is the most influential index amongst them in the forecast variance that can be accounted by s net at level of 55 75 our study indicates that the four water indices are interdependent and related so the water indices are influenced by movements in the other water indices

comovement in international equity markets a sectoral view abstract we investigate shifts in correlation patterns among international equity returns at the market level as well as the industry level we develop a novel bivariate garch model for equity returns with a smoothly time varying correlation and then derive a lagrange multiplier statistic to test the constant correlation hypothesis directly applying the test to weekly data from germany japan the uk and the us in the period 1980 2000 we find that correlations among the german uk and us stock markets have doubled whereas japanese correlations have remained the same both dates of change and speeds of adjustment vary widely across countries and sectors

multiple equilibria and persistence in aggregate fluctuations this paper explores the impact of incomplete markets and strong complementarities on the time series properties of aggregate activity we consider an economy which consists of a large number of industries whose production functions both are nonconvex and exhibit localized technological complementarities the productivity of each industry at t is determined by the production decisions of technologically similar industries at t 1 no markets exist to coordinate production decisions this feature implies that aggregate output dynamics for the model are quite different from those predicted by the associated arrow debreu economy first multiple stochastic equilibria exist in aggregate activity these equilibria are distinguished by differences in the mean and the variance of output second output movements are persistent as aggregate productivity shocks indefinitely affect real activity by shifting the economy across equilibria as a result the model can exhibit periods of boom and depression this abstract was borrowed from another version of this item

evolution of international stock and bond market integration influence of the european monetary union abstract this paper examines the dynamic relationship between daily stock and government bond returns of selected countries over the past decade to infer the state and progress of inter financial market integration we proceed to empirically investigate the influence of the european monetary union emu on time variations in inter stock bond market integration segmentation dynamics using a two step procedure first we document the downward trends in time varying conditional correlations between stock and bond market returns in european countries japan and the us second we investigate the causality and determinants of this interdependent relationship in particular whether the various macroeconomic convergence criteria associated with the emu have played a significant role we find that real economic integration and the reduction in currency risk have generally had the desired effect on financial integration but monetary policy integration may have created uncertain investor sentiments on the economic future of the emu thereby stimulating a flight to quality phenomenon

the discrete charm of the bourgeoisie quantum and continuous perspectives on innovation and growth this paper discusses the relative merits of discrete versus continuous perspectives on innovation technical change and economic growth it discusses the innovation time series literature in some detail to extract the continuous and clustering properties of the historical record on innovation it then proposes a mosaic avalanche model based on percolation theory and self organized criticality to address this question

a comparison of the dynamics of industrial clustering in computing and biotechnology abstract this paper compares the dynamics of the process by which industrial clusters emerged in the us computing and biotechnology industries it examines whether new companies are attracted by industry strength in particular sectors or by the strength of the science base at particular locations in biotechnology it also compares the growth of incumbent firms in the two industries and asks whether growth is boosted by being within a cluster the paper finds that within computing there are some important cross sectoral effects on entry while in biotechnology these cross sectoral effects are more limited in biotechnology the science base plays an important role in promoting entry the growth of incumbent firms in both industries is promoted by strength in the company s own sector and cross sectoral effects and the role of the science base are negligible

international business cycle co movement the role of fdi this article investigates the relationship between fdi and business cycle synchronization in the period 1982 to 2011 for eight industrialized countries we find that more synchronized business cycles are associated with stronger fdi relations in the period 1995 to 2011 but not before 1995 more intensive fdi links are also associated with a greater vulnerability to lagged output spillovers from abroad our findings suggest that fdi has become a separate channel through which economies may affect each other and that fdi stocks are now an essential aspect of economic interdependence

market organisation and trading relationships in this paper we give a theoretical model of buyers behaviour on a market for a perishable good where no prices are posted we show that if buyers learn from their own previous experience there is a sharp division between those who learn to be loyal to certain sellers and those who continue to shop around this feature remains in more general models which are simulated and is consistent with empirical data from the marseille fish market

the transition to chlorine free pulp revisited nordic heterogeneity in environmental regulation and r d collaboration the purpose of this paper is to analyze the development paths leading to the transition to cleaner bleaching technologies in the pulp industry it devotes particular attention to the key features o

aggregate spending and the terms of trade is there a laursen metzler effect this paper investigates the spending and current account effects of terms of trade shifts in a model where households maximize utility over an infinite planning period in the framework developed here an economy specialized in production must experience a fall in aggregate spending and a current surplus as a result of an unanticipated permanent worsening in its terms of trade the paper s model thus provides a setting in which the current account deficit predicted by laursen and metzier harberger and others fails to materialize

bond market and stock market integration in europe a smooth transition approach this article investigates whether there has been a structural increase in financial market integration in nine european countries and the us in the period 1980 to 2003 we employ a garch model with a smoothly time varying correlation to estimate the date of change and the speed of the transition between the low and high correlation regimes our test produces strong evidence of greater comovement across the board for both stock markets and government bond markets dates of change and speeds of adjustment vary widely across country linkages stock market integration is a more gradual process than bond market integration the impact of european monetary union emu is rather limited as it has mainly affected the timing of bond market correlation gains but hardly their size and has had little discernible effect on stock market integration

not for profit entrepreneurs abstract entrepreneurs who start new firms may choose not for profit status as a means of committing to soft incentives such incentives protect donors volunteers consumers and employees from ex post expropriation of profits by the entrepreneur we derive conditions under which completely self interested entrepreneurs opt for not for profit status despite the fact that this status limits their ability to enjoy the profits of their enterprises we also show that even in the absence of tax advantages unrestricted donations would flow to non profits rather than for profit firms because donations have more significant influence on the decisions of the non profits

learning from neighbours when payoffs from different actions are unknown agents use their own past experience as well as the experience of their neighbours to guide their decision making in this paper we develop a general framework to study the relationship between the structure of these neighbourhoods and the process of social learning we show that in a connected society local learning ensures that all agents obtain the same payoffs in the long run thus if actions have different payoffs then all agents choose the same action and social conformism obtains we develop conditions on the distribution of prior beliefs the structure of neighbourhoods and the informativeness of actions under which this action is optimal in particular we identify a property of neighbourhood structures local independencewhich greatly facilitates social learning simulations of the model generate spatial and temporal patterns of adoption that are consistent with empirical work

cooperation between rivals informal know how trading it has long been recognized that it is difficult for an innovating firm to fully appropriate the benefits arising from its innovations and that desired research might therefore not be performed nelson 1959 pp 297 306 one sometimes possible solution to this dilemma is cooperative r d conducted by firms who share the costs and benefits of particular r d projects johnson 1973

crime and social interactions the high variance of crime rates across time and space is one of the oldest puzzles in the social sciences this variance appears too high to be explained by changes in the exogenous costs and benefits of crime we present a model where social interactions create enough covariance across individuals to explain the high cross city variance of crime rates this model provides an index of social interactions which suggests that the amount of social interactions is highest in petty crimes moderate in more serious crimes and almost negligible in murder and rape

dynamic linkages among carbon energy and financial markets a smooth transition approach this article explores how price linkages between carbon allowances and market fundamentals in the eu emissions trading scheme eu ets vary over time i adopt a multivariate garch model that allows the conditional correlation between carbon energy and financial prices to change smoothly across regimes governed by functions of two transition variables that explain why price linkages vary i use i time as transition variable to allow for structural changes associated with institutional advances in the eu ets and ii implied volatility to account for heterogeneity in the behaviour of correlations in times of distress compared to calm periods the results point to a new pricing regime with much closer carbon energy price linkages in the second phase of the eu ets furthermore i find that correlations depend on market uncertainty conditions which exposes the link between carbon and financial markets due to common macroeconomic shocks during the current financial crisis

r d networks we develop a model of strategic networks that captures two distinctive features of interfirm collaboration bilateral agreements and nonexclusive relationships our analysis highlights the relationship between market competition firms incentives to invest in r d and the architecture of collaboration networks in the absence of firm rivalry the complete network where each firm collaborates with all others is uniquely stable industry profit maximizing and efficient by contrast under strong market rivalry the complete network is stable but intermediate levels of collaboration and asymmetric networks are more attractive from a collective viewpoint this suggests that competing firms may have excessive incentives to form collaborative links

long term global market correlations the correlation structure of the world equity markets varied considerably over the past 150 years and was high during periods of economic integration we decompose diversification benefits into two parts one component due to variation in the average correlation across markets and a another component due to the variation in the investment opportunity set from this we infer that periods of globalization have both benefits and drawbacks for international investors globalization expands the opportunity set but as a result the benefits from diversification rely increasingly on investment in emerging markets

trading uncertainty and market form this paper examines purely random multilateral matching among a large number of informationally isolated individuals who desire to trade the structure of links among traders is characterized by means of random graphs defined by a parameter that is chosen by prospective traders trading groups of all sizes including pairs as a special case result but the size distribution may contain a mass point at infinity that is within a certain subset of the entire economy trading uncertainty is entirely eliminated the equilibrium price distribution consists of a mass point and of a mixture of densities copyright 1990 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

why do firms do basic research with their own money abstractthe question to be addressed is why do private firms perform basic research with their own money interest in this question derives from both analytical and utilitarian considerations there is empirical evidence in the united states which provides the main context for this paper supporting the view that basic research makes a significant contribution to the productivity growth of the economy 4 7 it is widely held that social returns from basic research are significant and higher than private returns and it is for this reason that most such activities continue to be financed by the taxpayer this also implies that measures aimed at increasing basic research by the private sector will be welfare improving in the united states the federal government in the years since the second world war has provided the vast majority of all funds devoted to basic research although the federal share has been declining in recent years and although that share is at its lowest level in about 20 years it still constitutes about two thirds of the total 10 this abstract was borrowed from another version of this item

the effect of network structure in industrial diffusion processes abstract the development and diffusion of innovations involves groups of organizations with many different roles who interact with each other suppliers adopters third parties etc this paper examines the nature of the communication networks that exist between adopting organizations and from third parties and suppliers to adopters quantitative models of diffusion often assume that information about innovations flows along pre existing links that this information flows from adopters to non adopters directly and that there is perfect mixing in the population i e every actor has an equal chance of communicating with every other actor these are strong assumptions which should be subject to testing we investigate the impact of differing network topologies of communications and alternative models of social contagion on observed adoption patterns network topologies are also extended beyond the focal industry to include suppliers consultants and other customers we use a simulation model to test the effect of departures from traditional assumptions on the diffusion pattern and undertake an empirical field study to examine the prevalence of those departures in one specific industry our simulation findings suggest that network structure can have a substantial effect on the manner in which innovations diffuse while innovation specific communication links and communication through third parties does not change the shape of the penetration trajectory as much as it alters the places in the process where salesforce effort can offer the most leverage the empirical study shows strong evidence of imperfect mixing that both pre existing and innovation specific communication links are used and that communication through third parties may be as important to the diffusion process as direct links from adopters to potential adopters

production risk and the functional distribution of income in a developing economy tradeoffs and policy responses abstract we develop a stochastic endogenous growth model to examine the relationship between the volatility of growth and the factor distribution of income our framework incorporates two important features of developing economies the co existence of a modern and a traditional sector and the fact that the income generated in the traditional sector can escape taxation the relationship between volatility and factor distribution is complex depending upon the source of risk and the elasticity of substitution between capital and labor in the formal sector the policy options available to the government for counteracting changes in volatility are analyzed the second best optimal tax structure is also characterized

foreign debt supply in an imperfect international capital market theory and evidence abstract we investigate the determinants of foreign borrowing costs in a stochastically growing economy we find that these increase with the debt wealth ratio depending also upon the volatilities of domestic and foreign origin and the length of debt contract in addition the sensitivity of the short term debt supply to the debt wealth ratio exceeds that of long term debt and the effects of volatility on the borrowing premium growth of wealth and its volatility depend on the relative size of a direct effect and a secondary portfolio adjustment effect of the initial shock as well as the length of the debt contract panel regressions suggest that the empirical evidence generally support the theoretical predictions

making sense of institutions as a factor shaping economic performance abstract there has recently been a resurgence of interest in how institutions affect economic performance a review of this literature reveals that the concept of an institution means different things to different scholars both within economics and across the social sciences we discuss what factors unify the different definitions of institutions and develop a concept of institutions useful for the analysis of economic performance and economic growth in particular specifically we develop the notion of institutions as standard social technologies economic growth results from the co evolution of physical and social technologies

an optimizing analysis of the effects of world interest disturbances on the open economy term structure of interest rates abstract this paper studies the effects of world interest rate disturbances on the real domestic term structure of interest rates an intertemporal optimizing representative agent framework with variable employment and endogenous terms of trade is developed the economy faces an external borrowing constraint the adjustment of the short and long term rates as well as the discount bond yield curve is distinguished with the long rate and the yield curve derived recursively from the short both permanent and temporary world interest shocks are considered a notable result is that the yield curve exhibits relative maxima and minima for temporary disturbances

measuring european financial integration in this paper we present a set of specific measures to quantify the state and evolution of financial integration in the euro area five key markets are considered namely the money corporate bond government bond credit and equity markets building upon the law of one price we have developed two types of indicators that can be broadly categorized as price based and news based measures we have complemented these measures by a number of quantity based indicators mainly related to the evolution of the home bias results indicate that the unsecured money market is fully integrated while integration is reasonably high in the government and corporate bond markets as well as in the equity markets the credit market is among the least integrated especially in the short term segment

modeling sovereign yield spreads a case study of russian debt we construct a model for pricing sovereign debt that accounts for the risks of both default and restructuring and allows for compensation for illiquidity using a new and relatively efficient method we estimate the model using russian dollar denominated bonds we consider the determinants of the russian yield spread the yield differential across different russian bonds and the implications for market integration relative liquidity relative expected recovery rates and implied expectations of different default scenarios this paper develops a model of the termstructure of credit spreads on sovereign bonds that accommodates i default or repudiation the sovereign announces that it will stop making payments on its debt ii restructuring or renegotiation the sovereign and the lenders agree to reduce or postpone the remaining payments and iii a regime switch such as a change of government or the default of another sovereign bond that changes the perceived risk of future defaults we build on the framework of duffie and singleton 1999 showing that cash flows promised by a sovereign bond can be discounted using a default adjusted short termdiscount rate that reflects the m ean arrival rate and associated losses in market value upon arrival of each of the aforementioned types of credit events since a sovereign credit event is often not a liquidation event the model allows for continued trading and pricing of a sovereign instrument through credit events possibly after writedowns in face value or cash distributions to creditors on credit event dates additionally we accommodate the possibility that bonds issued by the same sovereign of exactly the same type but possibly of different maturities may be priced in the market using different discount factors reasons for this may include i bond covenants may not include cross default clauses that would force upon the default of one bond the simultaneous default of other bonds of the same type but of a different maturity for various strategic reasons related to internal

emu and european stock market integration the launch of the single currency in europe in january 1999 was preceded by a period of regulatory harmonization convergence in bond yields and inflation rates and strict fiscal policy across the eurozone countries we examine whether the 1990s also were characterized by increased stock market integration the results indicate that as forward interest differentials benchmarked against germany and inflation differentials benchmarked against the three best performing states shrank toward zero stock markets converged toward full integration the united kingdom a country that chose not to enter the eurozone shows no such increase in stock market integration

a strategic model of social and economic networks we study the stability and efficiency of social and economic networks when self interested individuals can form or sever links first for two stylized models we characterize the stable and efficient networks there does not always exist a stable network that is efficient next we show that this tension persists generally to assure that there exists a stable network that is efficient one is forced to allocate resources to nodes that are not responsible for any of the production we characterize one such allocation rule the equal split rule and another rule that arises naturally from bargaining of the players

policy entrepreneurship in the co evolution of institutions preferences and technology comparing the diffusion of totally chlorine free pulp bleaching technologies in the us and sweden abstract this paper uses the concept of policy entrepreneurship to explain the social processes underlying sustainable technical change in the pulp and paper industry in the 1990s it presents a detailed case study on the differences in the transition to and diffusion of totally chlorine free tcf pulp bleaching methods in sweden and the usa this change was sustained in the former while it was almost absent in the latter the paper studies the causes for this difference it looks at the complex coevolution of technology institutions and consumer preferences that has taken place in both countries and draws conclusions on how transitions to sustainable paths in production and consumption may be supported by economic and social policy

exchange rate regime volatility and international correlations on bond and stock markets focusing on the recent experience of the ems the paper examines the behavior of domestic daily returns on bond and stock markets with the objective of identifying whether there exist significant differences in the patterns of volatilities and international correlations between erm and non erm countries and across alternative episodes of erm exchange rate variability the paper provides substantial evidence that a credible peg is associated with a decline in bond market volatility the analysis also shows that an increase in exchange rate volatility is accompanied by a decline in international correlations between bond and to a lesser extent stock markets c 1999 published by elsevier science ltd all rights reserved

network structure and the diffusion of knowledge this paper models knowledge diffusion as a barter process in which agents exchange different types of knowledge this is intended to capture the observed practice of informal knowledge trading agents are located on a network and are directly connected with a small number of other agents agents repeatedly meet those with whom direct connections exist and trade if mutually profitable trades exist in this way knowledge diffuses throughout the economy we examine the relationship between network architecture and diffusion performance we consider the space of structures that fall between at one extreme a network in which every agent is connected to n nearest neighbours and at the other extreme a network with each agent being connected to on average n randomly chosen agents we find that the performance of the system exhibits clear small world properties in that the steady state level of average knowledge is maximal when the structure is a small world that is when most connections are local but roughly 10 percent of them are long distance the variance of knowledge levels among agents is maximal in the small world region whereas the coefficient of variation is minimal we explain these results as reflecting the dynamics of knowledge transmission as affected by the architecture of connections among agents

a unified approach to testing for serial correlation in stock returns this article provides a unified approach for testing serial correlation in stock returns the authors describe a general class of statistics that are linear combinations of consistent estimators of autocorrelations as special cases they show that this class captures many of the statistics studied in the recent finance and macroeconomics literature using this result the authors then provide a common perspective on the asymptotic distribution and power of these statistics copyright 1994 by university of chicago press

some stochastic processes of interdependent demand and technological diffusion of an innovation exhibiting externalities among adopters one frequently hears the opinion that as twentieth century society becomes more complex technological change assumes more significance and occurs at a more r apid pace investment in researclh and development results in a myriad of potential innovations yet as the frontiers of technology are plshed outward uncertainity about the usefulniess of innovations becomes an increasingly important factor in the decision whether or not to adopt the new innovation furthermore the decisions of individual economic agents tend to become increasingly interrelated many recent innovations are such that whether others adopt the device influences the benefits of adoption which accrue to a given consumer or firm such externalities may be positive for example consider a nation s decision to use the metric system the wearing of a style by a fashion leader a merchant s decision to accept a certain credit card or the purchase of a coinmunication device by someone with whom one desires to communicate or negative for instance imitation in the production of a faddish consumption item for which the potential market is limited or the pulrchase of a telephone by an obscene caller our goal is to analyze techn ological difflsioll with interdependencies when uncertainty and informational considerationis are an inherent part of the theoretical model the uncertainty may be of two types a technological ulncertainty the usefulness or quality of the innovation is at least partially unlknown and b adoption uncertainity incomplete or inaccurate knowledge about who is usinlg the innovation in our stochastic model adoptioni is reversible the decision to use the innovation is not permanent but rather agents may change their minds agents are not able to learn about the characteristics quality profitability usefulness etc of the innovation this assumption limits the applicability of

communication and coordination in social networks i model people in a coordination game who use a communication network to tell each other their willingness to participate the minimal sufficient networks for coordination can be interpreted as placing people into a hierarchy of social roles or stages initial adopters then followers and so on down to late adopters a communication network helps coordination in exactly two ways by informing each stage about earlier stages and by creating common knowledge within each stage we then consider two examples first we show that low dimensional networks can be better for coordination even though they have far fewer links than high dimensional networks second we show that wide dispersion of insurgents people predisposed toward participation can be good for coordination but too much dispersion can be bad although collective action depends on both social structure and individual incentives these integral aspects have been formalized separately in the fields of social network theory and game theory by considering them together this paper engages the classic question of which structures are conducive to coordination and shows that structure and strategy are related in a mutually interesting way here we consider a coordination game in which each person wants to participate only if others participate social structure is thought of as a communication network by which people tell each other their willingness to participate each person knows whether her neighbours in the network are willing but does not know about anyone else our model is thus a game of incomplete information in which each person given his local knowledge decides whether to participate the main result is a characterization of the minimal sufficient networks for coordination in terms of a hierarchy of social roles or stages initial adopters then followers and so on down to late adopters for example a communication network helps coordination in exactly two ways by informing each stage about earlier stages and by creating common knowledge within each stage we also consider two simple examples first we show that low dimension or strong link networks can be better for coordination even though they have far fewer links than high dimension or weak link networks second we show that wide dispersion of insurgents people predisposed toward participation can be good for coordination but too much dispersion can be bad this paper is built on the assumption that the most basic and common mechanism for coordination is the i ll go if you go mechanism individuals first communicate with each other about their preferences and then each individual chooses whether to participate or not hence a person s participation depends on what he knows about his neighbours it does not depend solely on their participation itself either through learning adaptation or social influence the physical analogies of contagion or diffusion are not

inventor networks in renewable energies the influence of the policy mix in germany technological change and gains in efficiency of renewable power generation technologies are to a large extent driven by governmental support various policy instruments that can broadly be categorized as technology push demand pull or systemic constitute part of the policy mix for renewable energies our goal is to gain insights into the influence of this policy mix on the intensity and organization of inventive activities for wind power and photovoltaics in germany since the 1980s we examine the effect of different instruments on the size and structure of co inventor networks based on patent data our results indicate notable differences between the technologies the network size for wind power is driven by technology push and systemic instruments while in photovoltaics demand pull is decisive for network growth by and large the instruments complement each other and form a consistent mix of policy instruments the structure of the networks is driven by demand pull for both technologies systemic instruments increase interaction especially in the wind power network and are complementary to demand pull in fostering collaboration

identifying the common component of international economic fluctuations a new approach in this paper we develop an aggregation procedure using time varying weights for constructing the common component of international economic fluctuations the methodology for deriving time varying weights is based on some stylised features of the data documented in the paper the model allows for a unified treatment of cyclical and seasonal fluctuations and also accommodates the dynamic propagation of shocks across countries we find evidence for a world business cycle as well as evidence for a distinct european common component we also find some evidence that macroeconomic fluctuations have become more closely linked across industrial economies in the period after 1973 the world economy has become more closely integrated in recent years due to increasing trade and financial flows across countries this has spurred interest in the question of how the ongoing phenomenon of globalisation has affected the transmission and propagation of business cycle fluctuations across national borders an important question in this context is whether a substantial fraction of economic fluctuations are country specific or if there exists a world business cycle which might be defined as fluctuations that are common across all countries more generally the comovement of macroeconomic aggregates across different countries has become a topic of increasing interest in both academic and policy circles these issues have implications in a number of dimensions an empirical analysis of the relative importance of country specific versus common international fluctuations is of relevance for determining the structure of certain classes of international business cycle models from a policy perspective strong comovement of output across countries at business cycle frequencies implies that external trade would be unlikely to play a significant role in dampening fluctuations domestic policies aimed at affecting the real exchange rate and thereby attempting to boost net exports in the short run would then tend to have limited impact the degree of synchronisation of business cycles across countries also has important implications for short run international policy coordination and for assessing the feasibility of monetary unions therefore identifying and analysing the common component of international economic fluctuations is relevant from a number of different perspectives