Browsing by Subject "Persistence"
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Item Open Access Analysis of real business cycle models with capital-skill complementarity(Bilkent University, 2009) Kılıç, SinemThe aim of this paper is to analyze the effects of a production function with capital-skill complementarity, as opposed to the standard Cobb-Douglas production function, on Real Business Cycle [RBC] models. Capital-skill complementarity is mostly used in open economy models to study the wage inequality but this production function has not been employed in closed economy real business cycle models. This paper shows that the production function with capital-skill complementarity causes even lower endogenous propagation of the impulse response functions than those of standard closed economy RBC models, which already have problems with regards to the persistence of output.Item Open Access Bidding structure, market efficiency and persistence in a multi-time tariff setting(Elsevier, 2016) Avci-Surucu, E.; Aydogan, A. K.; Akgul, D.The purpose of this study is to examine the fractal dynamics of day ahead electricity prices by using parametric and semi parametric approaches for each time zone in a multi-time tariff setting in the framework of bidding strategies, market efficiency and persistence of exogenous shocks. We find that that electricity prices have long term correlation structure for the first and third time zones indicating that market participants bid hyperbolically and not at their marginal costs, market is not weak form efficient at these hours and exogenous shocks to change the mean level of prices will have permanent effect and be effective. On the other hand, for the second time zone we find that price series does not exhibit long term memory. This finding suggests the weak form efficiency of the market in these hours and that market participants bid at their marginal costs. Furthermore this indicates that exogenous shocks will have temporary effect on electricity prices in these hours. These findings constitute an important foundation for policy makers and market participants to develop appropriate electricity price forecasting tools, market monitoring indexes and to conduct ex-ante impact assessment.Item Open Access Is Romeo dead? On the persistence of organisms(Springer Netherlands, 2018) Tzinman, R.According to a prominent view of organism persistence (“vitalicism”), organisms cease to exist at death. According to a rival view (“somaticism”), organisms can continue to exist as dead organisms. Most of the arguments in favor of the latter view rely on linguistic and common sense intuitions. I propose a new argument for somaticism by appealing to two other sources that have thus far not figured in the debate: the concept of naturalness, and biological descriptions of organisms, in particular in ethology and ecology. I show that if we hone in on the relevant notion of naturalness, we can show that organisms can (and often do) continue to instantiate the natural property being an organism after death.Item Open Access Measuring euro area monetary policy(Elsevier, 2019) Altavilla, C.; Brugnolini, L.; Gürkaynak, Refet S.; Motto, R.; Ragusa, G.We map ECB policy communication into yield curve changes and study the information flow on policy dates. A byproduct is the publicly available Euro Area Monetary Policy Event-Study Database (EA-MPD), containing intraday asset price changes. We find that Policy Target, Forward Guidance and Quantitative Easing factors capture about all the variation in the yield curve, with different factors appearing in the windows covering the policy decision announcement and the press conference, and having time-varying variance shares. We study sovereign yields, exchange rates, stock prices, persistence of effects and response asymmetry. Our methodology can be implemented for any policy-related event.Item Open Access The role of bcsE gene in the pathogenicity of Salmonella(Oxford University Press, 2021-07-19) Özdemir, Caner; Akçelik, N.; Özdemir, F. N.; Evcili, İrem; Kahraman, Tamer; Gürsel, İhsan; Akçelik, M.The effects of the bcsE gene and BcsE protein on bacterial physiology and pathogenicity in SalmonellaTyphimurium and Salmonella Group C1 were investigated. It was observed that biofilm and pellicle formation did not occur in the bcsE gene mutants of wild-type strains. Besides, the ‘rdar’ (red, dry, rough) biofilm morphotype in wild-type strains changed significantly in the mutants. In terms of the bcsE gene, the swimming and swarming motility in mutant strains showed a dramatic increase compared to the wild-type strains. The Salmonella bcsE gene was cloned into Escherichia coli BL21, and the his-tagged protein produced in this strain was purified to obtain polyclonal antibodies in BALB/c mice. The antibodies were showed labeled antigen specificity to the BscE protein. As a result of immunization and systemic persistence tests carried out with BALB/c mice, BscE protein was determined to trigger high levels of humoral and cellular responses (Th1 cytokine production, IgG2a/IgG1 > 1). Systemic persistence in the liver and spleen samples decreased by 99.99% and 100% in the bcsE mutant strains. Finally, invasion abilities on HT-29 epithelial cells of wild-type strains were utterly disappeared in their bcsE gene mutant strains.