Growth of Solutions with Positive Initial Energy to Systems of Nonlinear Wave Equations with Damping and Source Terms

We consider initial-boundary conditions for coupled nonlinear wave equations with damping and source terms. We prove that the solutions of the problem are unbounded when the initial data are large enough in some sense

Türkiye İhracatının Ölüm-Kalım Meselesi

The standard theory of international trade almost implies that trade patterns are highly static and persistent. Therefore, the issue of trade duration is generally ignored in these standard trade models. The literature on trade duration has been popular since the seminal works by Besedes and Prusa (2006a-b). These papers reveal that trade relationships are often very short-lived contrary to previously thoughts. In line with this unexpected result, this study provides a thorough statistical description and regression analysis of the duration of Turkish exports. The aim of this study two-fold. Firstly, it attempts to identify the duration of Turkish exports by performing a highly detailed analysis of descriptive statistics and the Kaplan-Meier method. Secondly, this study explores the factors that affect on the hazard rates of export flows. To this end, two different regression analysis are performed by using Cox proportional hazard model and discrete-time Probit, Logit and Cloglog hazard models. The detailed trade data reported by CEPII-BACI are employed to investigate Turkey's export to 245 partners from 1998 to 2013 according to the 6-digit Harmonized system. Results obtained from the analysis of descriptive statistics suggest that the duration of Turkish exports is very short-lived. The median and mean duration of Turkish exports are merely one year and 3,41, respectively. 51% of all trade spells, however, cease during the first year. The Kaplan-Meier estimates of survival functions show that all survival curves are downward sloping with decreasing rate and about 42% of export relationships is likely to fail in the first year. The results of regression analysis indicate that discrete-time Logit hazard model is more suitable hazard model for estimation. Empirical evidences of discrete-time Logit hazard model demonstrate that common language, common border, importer GDP, relative real exchange rate, initial export value, lagged duration, total export value, number of export products and number of export markets variables have a strong negative impact on the hazard rates of export flows. Whereas distance, difference in GDP per capita and EU-27 variables have a positive effect on the hazard rates of export flows

Non-existence of solutions for a Timoshenko equations with weak dissipation

In this paper, we consider the following Timoshenko equation utt + ( 2u ( M ((( ( u (( 2( ( u + ut = (u( q-1 u associated with initial and Dirichlet boundary conditions. We prove the non-existence of solutions with positive and negative initial energy

Ticaret Anlaşmalarının Türkiye’nin İhracat Dinamiğine Etkisi: Yaygın ve Yoğun Ticaret.

The objective of this study is to analyze the effects of the Customs Union (CU) and Free Trade Agreements (FTA) on the extensive and intensive margins. For this purpose, first, Turkey’s export data set composing HS-6 digit product level statistics for period 1996 to 2011 with 172 countries has been decomposed into extensive and intensive margins by using the decomposition method of export shares developed by Hummels and Klenow (2005) related Feenstra (1994). Then, effects of the CU and FTA on both extensive and intensive margins has been identified with the Gravity model. All analyzes has been performed for the exports of the total goods as well as the exports of the final and intermediate goods. Empirical results for the Gravity model show that the effects of the CU and FTA on the extensive and intensive margins are statistically significant. Furthermore, the effect of the CU on the extensive and intensive margins is greater than that of the FTA

BLOW UP OF POSITIVE INITIAL-ENERGY SOLUTIONS FOR THE EXTENSIBLE BEAM EQUATION WITH NONLINEAR DAMPING AND SOURCE TERMS

In this work, we study the following extensible beam equationu_{tt}+△²u-M(‖∇u‖²)△u+|u_{t}|^{p-1}u_{t}=|u|^{q-1}uwith initial and boundary condition. Under suitable conditions on the initial datum, we prove that the solution blow up in finite time with positive initial-energy

Ticaret Anlaşmalarının Türkiye’nin İhracat Dinamiğine Etkisi: Yaygın ve Yoğun Ticaret.

The objective of this study is to analyze the effects of the Customs Union (CU) and Free Trade Agreements (FTA) on the extensive and intensive margins. For this purpose, first, Turkey’s export data set composing HS-6 digit product level statistics for period 1996 to 2011 with 172 countries has been decomposed into extensive and intensive margins by using the decomposition method of export shares developed by Hummels and Klenow (2005) related Feenstra (1994). Then, effects of the CU and FTA on both extensive and intensive margins has been identified with the Gravity model. All analyzes has been performed for the exports of the total goods as well as the exports of the final and intermediate goods. Empirical results for the Gravity model show that the effects of the CU and FTA on the extensive and intensive margins are statistically significant. Furthermore, the effect of the CU on the extensive and intensive margins is greater than that of the FTA

In vivo performance of antibiotic embedded electrospun PCL membranes for prevention of abdominal adhesions

The aim of this study was to prepare nonwoven materials from poly(-caprolactone) (PCL) and their antibiotic containing forms by electrospinning, so as to prevent postsurgery induced abdominal adhesions in rats. -Caprolactone was first polymerized by ring-opening polymerization, and then it was processed into matrices composed of nanofibers by electrospinning. A model antibiotic (Biteral®) was embedded within a group of PCL membranes. In the rat model, defects on the abdominal walls in the peritoneum were made to induce adhesion. The plain or antibiotic embedded PCL membranes were implanted on the right side of the abdominal wall. No membrane implantation was made on the left side of the abdominal wall that served as control. Macroscopical and histological evaluations showed that using these barriers reduces the extent, type, and tenacity of adhesion. The antibiotic embedded membranes significantly eliminated postsurgery abdominal adhesions, and also improved healing

Blow-up phenomena for a p(x)-biharmonic heat equation with variable exponent

In this paper, we deal with a p(x)-biharmonic heat equation with variable exponent under Dirichlet boundary and initial condition. We prove the blow up of solutions under suitable conditions

In vitro and in vivo degradation of non-woven materials made of poly(e-caprolactone) nanofibers prepared by electrospinning at different conditions

The aim of this study was to prepare non-woven materials from a biodegradable polymer, poly(ε-caprolactone) (PCL) by electrospinning. PCL was synthesized by ring-opening polymerization of ε-caprolactone in bulk using stannous octoate as the catalyst under nitrogen atmosphere. PCL was then processed into non-woven matrices composed of nanofibers by electrospinning of the polymer from its solution using a high voltage power supply. The effects of PCL concentration, composition of the solvent (a mixture of chloroform and DMF with different DMF content), applied voltage and tip–collector distance on fiber diameter and morphology were investigated. The diameter of fibers increased with the increase in the polymer concentration and decrease in the DMF content significantly. Applied voltage and tip–collector distance were found critical to control 'bead' formation. Elongation-at-break, ultimate strength and Young's modulus were obtained from the mechanical tests, which were all increased by increasing fiber diameter. The fiber diameter significantly influenced both in vitro degradation (performed in Ringer solution) and in vivo biodegradation (conducted in rats) rates. In vivo degradation was found to be faster than in vitro. Electrospun membranes were more hydrophobic than PCL solvent-casted ones; therefore, their degradation was a much slower process