SU(3) family symmetry and neutrino bi-tri-maximal mixing

The observed large mixing angles in the lepton sector may be the first signal for the presence of a non-Abelian family symmetry. However, to obtain the significant differences between the mixing of the neutrino and charged fermion sectors, the vacuum expectation values involved in the breaking of such a symmetry in the two sectors must be misaligned. We investigate how this can be achieved in models with an SU(3) family symmetry consistent with an underlying GUT. We show that such misalignment can be achieved naturally via the see-saw mechanism. We construct a specific example in which the vacuum (mis)alignment is guaranteed by additional symmetries. This model generates a fermion mass structure consistent with all quark and lepton masses and mixing angles. Neutrino mixing is close to bi-tri-maximal mixing.Comment: References added; typos correcte

Finance and growth : Schumpeter might be right

Joseph Schumpeter argued in 1911 that the services provided by financial intermediaries - mobilizing savings, evaluating projects, managing risk, monitoring managers, and facilitating transactions -stimulate technological innovation and economic development. The authors present evidence that supports this view. Examining a cross-section of about 80 countries for the period 1960-89, they find that various measures of financial development are strongly associated with both current and later rates of economic growth. Each measure has shortcomings but all tell the same story: finance matters. They present three main findings, which are robust to many specification tests: The average level of financial development for 1960-89 is very strongly associated with growth for the period. Financial development precedes growth. For example, financial depth in 1960 (the ratio of broad money to GDP) is positively and significantly related to real per capita GDP growth over the next 30 years even after controlling for a variety of country-specific characteristics and policy indicators. Financial development is positively associated with both investment rate and the efficiency with which economies use capital. Much work remains to be done, but the data are consistent with Schumpeter's view that the services provided by financial intermediaries stimulate long-run growth.Achieving Shared Growth,Governance Indicators,Economic Theory&Research,Inequality,Economic Growth

Financial indicators and growth in a cross section of countries

The authors use existing measures of the financial system - and construct many new measures - to document the relationship between the financial system and long-run growth in a cross-section of countries between 1960 and 1989. They consider various measures of the size of the financial system, the importance of different financial institutions, the financial system's allocation of credit, the financial system's efficiency, and the degree of financial repression. They use graphs, correlations, and regressions to gauge the robustness of the partial correlation between growth and the financial indicators. They also examine two channels through which financial indicators may be linked to growth: the share of GDP allocated to investment; and the efficiency with which resources are used. They find that many of the financial system indicators are significantly correlated with growth through both investment and efficiency. Moreover, many of these partial correlations remain strong after controlling for initial conditions, dummy variables for Africa and Latin America, and measures of monetary, fiscal, and trade performance. Their analysis suggests that it is empirically important to identify which financial intermediaries aredoing the intermediation and to whom the financial system is allocating credit rather than simply using proxies for the overall size of the financial system, as has been common in past studies.Economic Theory&Research,Macroeconomic Management,Financial Economics,Achieving Shared Growth,Governance Indicators

Capital fundamentalism, economic development, and economic growth

Few economic ideas are as intuitive as the notion that increasing investment is the best way to raise future output. This idea was the basis for the theory"capital fundamentalism."Under this view, differences in national stocks of capital were the primary determinants of differences in levels of national product. Capital fundamentalists viewed capital accumulation as central to increasing the rate of economic growth. Evidence to support this view was based mostly on case studies of less developed countries. Neoclassical growth theory and growth accounting research indicated that differences in patterns of investment and capital formation were not the main factors that led nations to be rich or poor, fast-growing or slow. Technology, rather than capital accumulation, appeared to drive improvements in living standards in the long run. Evidence to support this view was based mostly on data from advanced countries. Recent research on growth and development has lent support to two conclusions that capital fundamentalists would find attractive: that differences in national patterns of physical capital accumulation can explain many differences in levels of national product, and that increases in national investment rates can produce major increases in rates of economic growth. The authors find that although the capital-output ratio varies positively with the level of per capita income, there is little support for the view that capital fundamentalism should guide the agenda for research and policy advice. Extending standard growth accounting procedures to a broad sample of 105 countries, they find: 1) differences in capital-per-person explain few of the differences in output-per-person across countries; 2) growth in capital stocks account for little of output growth across countries; and 3) the ratio of investment to Gross Domestic Product is strongly associated with economic growth - but there is more reason to believe that economic growth causes investment and savings than investment and savings cause economic growth.Economic Growth,Economic Theory&Research,Banks&Banking Reform,International Terrorism&Counterterrorism,Achieving Shared Growth

Qualitative System Identification from Imperfect Data

Experience in the physical sciences suggests that the only realistic means of understanding complex systems is through the use of mathematical models. Typically, this has come to mean the identification of quantitative models expressed as differential equations. Quantitative modelling works best when the structure of the model (i.e., the form of the equations) is known; and the primary concern is one of estimating the values of the parameters in the model. For complex biological systems, the model-structure is rarely known and the modeler has to deal with both model-identification and parameter-estimation. In this paper we are concerned with providing automated assistance to the first of these problems. Specifically, we examine the identification by machine of the structural relationships between experimentally observed variables. These relationship will be expressed in the form of qualitative abstractions of a quantitative model. Such qualitative models may not only provide clues to the precise quantitative model, but also assist in understanding the essence of that model. Our position in this paper is that background knowledge incorporating system modelling principles can be used to constrain effectively the set of good qualitative models. Utilising the model-identification framework provided by Inductive Logic Programming (ILP) we present empirical support for this position using a series of increasingly complex artificial datasets. The results are obtained with qualitative and quantitative data subject to varying amounts of noise and different degrees of sparsity. The results also point to the presence of a set of qualitative states, which we term kernel subsets, that may be necessary for a qualitative model-learner to learn correct models. We demonstrate scalability of the method to biological system modelling by identification of the glycolysis metabolic pathway from data

Radiative Corrections to Chargino Production with Polarized Beams

We show that radiative corrections to chargino production in electron-positron annihilation with polarized beams can be large especially in the case of right handed electrons. In addition, there is some dependency on the squark masses that allows us to extract information about the squark spectrum from the chargino production.Comment: 4 pages, including 4 figures. Talk given at Linear Collider Workshop 2000--LCWS, Fermilab, Chicago, October 24-28, 200

Radiatively Corrected Chargino Pair Production at LEP2

One-loop radiative corrections to the production cross section of a pair of light charginos in e+e- colliders are calculated within the MSSM. Top and bottom quarks and squarks are considered in the loops, and they are renormalized using the MS-bar scheme. If the center of mass energy is equal to 192 GeV, positive corrections typically of 10% to 15% are found when the squark mass parameters are equal to 1 TeV.Comment: 6 pages, including 5 figures. Latex. Talk given by M.A.D. at the International Workshop "Beyond the Standard Model: From Theory to Experiment", 13--17 October 1997, Valencia, Spai

Policy, Technology Adoption, and Growth

This paper describes a simple model of technology adoption which combines the two engines of growth emphasized in the recent growth literature: human capital accumulation and technological progress. Our model economy does not create new technologies, it simply adopts those that have been created elsewhere. The accumulation of human capital is closely tied to this adoption process: accumulating human capital simply means learning how to incorporate a new intermediate good into the production process. Since the adoption costs are proportional to the labor force, the model does not display the counterfactual scale effects that are standard in models with endogenous technical progress. We show that our model is compatible with various standard results on the effects of economic policy on the rate of growth.

How do national policies affect long-run growth? : a research agenda

The authors suggest that there are important opportunities to empirically evaluate the theoretically predicted channels from policy to growth. They propose a research agenda based on the endogenous growth literature, designed to address the questions: How do national policies affect long-run growth? Which policies strongly affect long-run growth? Do policies explain why some poor countries have stagnated and others have advanced? Do policies explain successive periods of rapid growth and stagnation in the same country? And to what extent do national policies rather than external influences explain the stagnation of many countries in Africa, Latin America, and Asia in the 1980s? The authors discuss five national policies: fiscal policy; monetary policy; trade intervention; financial policies; and openness to foreign capital. Their analytical framework is based on the simple idea that all factors of production can be increased by investing in human or physical capital. Economic growth will be related to policies that affect the incentive to invest and the efficient use of capital and intermediate inputs. Such a framework can be used to consider which policies affect the long-run growth rate rather than affecting simply the level of income once and for all.Governance Indicators,Economic Conditions and Volatility,Achieving Shared Growth,Environmental Economics&Policies,Economic Growth