The Linkage Between Public and Private Investment: A Co-integration Analysis of a Panel of Developing Countries

This study uses panel data from 19 developing countries from 1980 to 1997 to examine the impact of public investment on private investment. A model is developed to identify both the short run and long-run effects of public investment on private investment, builds in the role of uncertainty on investment, and uses co-integration tests on panel data to check the time series properties of the data. The empirical results show that public investment is complementary to private investment in developing economies, and that credit constraints restrict the amount of private investment.

A Method for Identifying General Aviation Airports that are Candidates for Runway Extensions: A Planning Model for State Aviation Systems

One of the most important characteristics of an airport is the length of its longest runway: that length determines the types of aircraft that can use the airport and provides a margin of safety for users. A runway extension, therefore, would enhance the utility of many airports. But resources are scarce, and if funds are to be allocated at the state level, state officials need a method for determining which airports could best use a longer runway. Consideration of demographic factors enhances the traditional engineering analysis approach to runway evaluation. This combined approach is more consistent with the goals of comprehensive airport planning. This paper describes a model that uses regression analysis to compare airports in Alabama, taking into account a number of different demographic factors and airport related factors. A linear regression model was used to evaluate how an airport\u27s runway length compared to others around the state with similar characteristics. The residuals from the regressions were used to identify those airports with relatively short runways, considering their other characteristics. The regression analysis identified 22 of the 106 public-use airports in Alabama as having runways substantially shorter than their other characteristics would predict

Constitutions and Democracy

Cet article étudie le rôle des démocraties dans un système constitutionnel et montre comment la démocratie menace les droits et libertés des individus. L’exemple des Etats-Unis illustre l’argument. L’article montré également que les réformes économiques, et non politiques, sont la clé de la prospécrité (mais pas nécessairement de la liberté) ; ce n’est pas la démocratie mais un système dans lequel les droits sont protégés constitutionnellement qui assure la liberté politique et la liberté économique. La démocratie, si elle n’est pas contrôlée, est aussi dangereuse qu’une dictature.The purpose of this paper is to discuss the role of democracy in a system of constitutional law, and to show how democracy threatens rights and freedom, using the case of the United States to illustrate the point. There are some minor and correlated themes : first, economic reforms, not political reforms, are the key to prosperity (although not freedom) ; second, the key to both political and economic freedom is a system of constitutionally protected rights, not democracy. Democracy, unchecked, is as much a threat to freedom as dictatorship

Consumption Externalities and Economic Welfare

The distinction between technological and pecuniary externalities, usually made in production, can also be applied to consumption. Technological externalities create resource misallocations while pecuniary externalities do not. Taking a household production approach to consumption, this paper shows that many cases in which there are external effects on people's utility functions are pecuniary externalities, and public policy should ignore them. The economic literature has been inconsistent in its treatment of pecuniary consumption externalities, and this paper provides a framework for analysis in cases where the actions of some people affect the utility of others.Consumption; Economic Welfare; Externalities; Welfare

Specification Search and Levels of Significance in Econometric Models

This paper describes the problem specification searches pose for inference, presents the results of some simulations for purposes of illustration, and uses the bootstrapping procedure to give a better estimate of statistical significance than a standard t-test. The value of the illustrations of specification searches is that they help demonstrate the severity of the problem. The examples presented here illustrate that in most cases, a researcher can undertake specification search and report a statistically significant result regardless of whether the variables in a regression equation are actually related. The bootstrap procedure used to analyze the specification searches does provide another way to examine the true statistical significance of empirical results. Two different specification searches are examined: a "drop insignificant coefficients" search and a "biggest t-ratio" search. Both are shown to lead to larger than reported standard errors. In general, standard errors get larger if a specification search has taken place, but exactly how much larger must be determined on a case-by-case basis.

Relationship of the genes for Chediak-Higashi syndrome (beige) and the T-cell receptor [gamma] chain in mouse and man

The genetic linkage of Chediak-Higashi syndrome and its murine analog, beige (bg), to the T-cell receptor (TCR-[gamma]) [gamma] chain gene is further defined. Previous studies using recombinant inbred strains of mice demonstrated that the murine bg gene is genetically linked to a murine TCR-[gamma] gene. We report that in the mouse the frequency of recombination between these two markers is 0.025. Further, we tested the hypothesis that these two genes are linked in the human genome by analyzing restriction fragment length polymorphisms (RFLPs) in five families with children afflicted with Chediak-Higashi syndrome. In three families, RFLPs in TCR-[gamma] genes were inherited discordantly from Chediak-Higashi syndrome, demonstrating nonlinkage. We postulate that there is an evolutionary chromosomal breakpoint between the bg gene and the TCR-[gamma] gene.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26520/1/0000058.pd

Sustained proliferation in cancer: mechanisms and novel therapeutic targets

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression