Do stock returns lead real economic activity? Evidence from seasonal cointegration analysis

This paper investigates the causal relationship between the stock returns and real economic activity in seasonal unit roots and seasonal cointegration framework by taking into account of seasonal behaviors of the stock returns and industrial production as a proxy of real economic activity. We use seasonally unadjusted quarterly Turkish data series that covers the period from first quarter of 1987 to the third quarter of 2009. The empirical results support evidence for the existence of the causal relationship between stock returns and real economic activity. We determine unidirectional causality running from the real economic activity to the stock returns in the six-monthly term. The empirical findings support that only the real economic activity provides the forecasting ability for the stock returns and there is no feedback relationship between the stock returns and the real economic activity.Stock Returns, Real Economic Activity, Seasonal Cointegration

TURKIYE EKONOMISINDE BUTCE ACIGININ SURDURULEBILIRILIGININ ANALIZI

Economic sustainability is consequent to the sustainability of budget policies. By analyzing sustainability of budget policies, it is possible to ascertain if any change in fiscal and monetary policy is necessary or not. In this study, budget deficit sustainability was researched for the period of 1987:1–2007:3 under Inter-temporal Borrowing Constraint (IBC) approach. It is presumed that, crisis occurred and measures taken within the mentioned period caused structural change. Therefore, firstly by using Bai-Perron multiple break tests, a break was determined in the period 2003:2. Sustainability of budget deficit was analyzed for the whole period and two sub-periods respectively. Ng-Perron test for unit roots and Stock-Watson and Shin DOLS tests of cointegration were used in this analysis. Consequently, the results support the weak sustainability for the whole period and also for sub-periods.Sustainability, Budget Deficit, Bai-Perron Multiple Break Test, Ng-Perron Unit Roots Tests, Stock-Watson DOLS Cointegration Test, Shin’s Cointegration Test

Parasitic influences on the host genome using the molluscan model organism biomphalaria glabrata

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The freshwater snail Biomphalaria glabrata is an intermediate host for Schistosoma mansoni parasites, causing one of the most prevalent parasitic infections in mammals, known as schistosomiasis (Bilharzia). Due to its importance in the spread of the disease B. glabrata has been selected for whole genome sequencing and is now a molluscan model organism. In order to aid the sequencing project and to understand the structure and organisation of B. glabrata’s genome at the chromosomal level, a G-banded karyotype has been established. Unlike in any other previous reports, two heteromorphic chromosomes have been identified in the genome of B. glabrata and for the first time snail ideograms have been produced. In addition to characterising the snail chromosomes, a methodology for mapping single copy B. glabrata genes onto these chromosomes has also been established, and 4 genes have successfully been mapped using fluorescence in situ hybridisation. In the relationship between a parasite and a host organism, it is of fundamental importance to understand the basic biology and interfere with the life cycle to reveal how the parasite controls and elicits host gene expression for its own benefit. This study is also directly addressing this aspect of host – parasite interactions by investigating the effects of schistosome infection on the genome and cell nuclei of the host snail B. glabrata. Upon infection with S. mansoni miracidia, genes known to be involved in the host response to the parasite are dramatically relocated within the interphase snail nuclei. These events are in conjunction with the up-regulation of gene expression, indicating a parasite induced nuclear event. Moreover, a differential response between the schistosome-resistant and schistosome-susceptible snails is also reported. This is the first time this has been described in a host – pathogen relationship. The precise organisation of the genome is critical for its correct functioning. The genome is non-randomly organised and this level of organisation is very much influenced by the nuclear architecture. Being a molluscan model organism with the availability of a unique cell line, B. glabrata is a remarkable organism for the studies of nuclear and genome biology. For this reason, in this thesis the snail nuclear architecture was also investigated. For the first time PML bodies, transcription factories, and nuclear myosin 1 beta have been visualised in the snail nuclei. A heat shock system was also developed to study the role of these structures in the snail. Upon heat stimuli gene loci were found to reposition and co-localise with transcription factories, which was in parallel with the up-regulation of gene expression. The mechanism of this genome reorganisation was explored by investigating nuclear motor structures in the snail. By using a motor inhibitor on snail cells, gene repositioning and subsequent expression after heat shock was blocked. This is the first time this has been shown in any organism. Thus, due to the ease of use of the snails with respect to maintenance, handling, and treatments, B. glabrata is making a very useful new model organism to study spatial genomic events

Symbolic computation of exact solutions expressible in hyperbolic and elliptic functions for nonlinear PDEs

Algorithms are presented for the tanh- and sech-methods, which lead to closed-form solutions of nonlinear ordinary and partial differential equations (ODEs and PDEs). New algorithms are given to find exact polynomial solutions of ODEs and PDEs in terms of Jacobi's elliptic functions. For systems with parameters, the algorithms determine the conditions on the parameters so that the differential equations admit polynomial solutions in tanh, sech, combinations thereof, Jacobi's sn or cn functions. Examples illustrate key steps of the algorithms. The new algorithms are implemented in Mathematica. The package DDESpecialSolutions.m can be used to automatically compute new special solutions of nonlinear PDEs. Use of the package, implementation issues, scope, limitations, and future extensions of the software are addressed. A survey is given of related algorithms and symbolic software to compute exact solutions of nonlinear differential equations.Comment: 39 pages. Software available from Willy Hereman's home page at http://www.mines.edu/fs_home/whereman