Assessment of Institutional Thickness in the Turkish Context

Peer reviewedPublisher PD

Chiral quark models and their applications

We give an overview of chiral quark models, both for the pure light sector and the heavy-light sector. We describe how such models can be bosonized to obtain welWe give an overview of chiral quark models, both for the pure light sector and the heavy-light sector. We describe how such models can be bosonized to obtain well known chiral Lagrangians which can be inferred from the symmetries of QCD alone. In addition, we can within these models calculate the coefficients of the various pieces of the chiral Lagrangians. We discuss a few applications of the models, in particular, \bbar mixing and processes of the type $B \to D \bar{D}$, where $D$ might be both pseudoscalar and vector. We suggest how the formalism might be extended to include light vectors ($\rho,\omega,K^*$), and heavy to light transitions like $B \to \pi$. l known chiral Lagrangians which can be inferred from the symmetries of QCD alone. In addition, we can within these models calculate the coefficients of the various pieces of the chiral Lagrangians. We discuss a few applications of the models, in particular, \bbar mixing and processes of the type $B \to D \bar{D}$, where $D$ might be both pseudoscalar and vector. We suggest how the formalism might be extended to include light vectors ($\rho,\omega,K^*$), and heavy to light transitions like $B \to \pi$.Comment: 37 pages, 16 figures. Dedicated to the memory of Prof. D. Tadic, Submitted to Fizika B, Zagre

Line Spring Model and Its Applications to Part-Through Crack Problems in Plates and Shells

The line spring model is described and extended to cover the problem of interaction of multiple internal and surface cracks in plates and shells. The shape functions for various related crack geometries obtained from the plane strain solution and the results of some multiple crack problems are presented. The problems considered include coplanar surface cracks on the same or opposite sides of a plate, nonsymmetrically located coplanar internal elliptic cracks, and in a very limited way the surface and corner cracks in a plate of finite width and a surface crack in a cylindrical shell with fixed end

Level dependent annuities: Defaults of multiple degrees

Motivated by the risk of stopped debt coupon payments from a leveraged company in financial distress, we value a level dependent annuity contract where the annuity rate depends on the value of an underlying asset-process. The range of possible values of the asset is divided into a finite number of regions. The annuity rate is constant within each region, but may differ between the regions. We consider both in finite and finite annuities, with or without bankruptcy risk, i.e., bankruptcy occurs if the asset value process hits an absorbing boundary. Such annuities are common in models of debt with credit risk in financial economics. Suspension of debt service under the US Chapter 11 provisions is one well-known real-world example. We present closed-form formulas for the market value of such multi-level annuities contracts when the market value of the underlying asset is assumed to follow a geometric Brownian motion.Multi-level annuity; credit risk; financial distress

A Model of Deferred Callability in Defaultable Debt

Banks and other financial institutions raise hybrid capital as part of their risk capital. Hybrid capital has no maturity, but, similarily to most corporate debt, includes an embedded issuer's call option. To obtain acceptance as risk capital, the first possible exercise date of the embedded call is contractually deferred by several years, generating a protection period. The existence of this call feature affects the issuer's optimal bankruptcy decision, in addition to the value of debt. We value the call feature as a European option on perpetual defaultable debt. We do this by first modifying the underlying asset process to incorporate a time dependent bankruptcy level before the expiration of the embedded option. We identify a call option on debt as a fixed number of put options using a modified exercise price on a modified asset, which is lognormally distributed, as opposed to the market value of debt. To include the possibility of default before the expiration of the option we apply barrier options results. The formulas are quite general and may be used for valuing both embedded and third-party options. All formulas are developed in the seminal and standard Black-Scholes-Merton model and, thus, standard analytical tools such as 'the greeks', are immediately available.Callable perpetual debt; barrier options

Using Bank Mergers and Acquisitions to Understand Lending Relationships

We study how firm-bank lending relationships affect firms' access to and terms of credit. We use bank mergers and acquisitions (M&As) as exogenous events that affect lending relationships. Bank M&As lead to organisational changes at the involved banks, which may reduce the amount of soft information encompassed in the firm-bank relationship. Using a unique Norwegian dataset, which combines information on companies' bank accounts, annual accounts, bankruptcies, and bank M&As for the years 1997-2009, we find that domestic bank mergers increase interest rate margins by 0.24 percentage points for opaque small and medium sized rms, relative to less opaque firms. Since, due to information asymmetries, opaque firms are typically more dependent on bank lending relationships, our results indicate that these relationships are advantageous for such borrowers, and the destruction of a relationship during the merger process has adverse effects for the firm. Conversely, the results are not consistent with a lock-in effect due to an information monopoly by the relationship lender that on average increases a firm's borrowing costs over its life cycle. The results are robust to the inclusion of variables that control for eects of market competition.Bank Mergers and Acquisitions; Lending Relationships

Elasticity Solution of an Adhesively Bonded Cover Plate of Various Geometries

The plane strain of adhesively bonded structures consisting of two different isotropic adherends is considered. By expressing the x-y components of the displacements in terms of Fourier integrals and using the corresponding boundary and continuity conditions, the integral equations for the general problem are obtained and solved numerically by applying Gauss-Chebyshev integration scheme. The shear and the normal stresses in the adhesive are calculated for various geometries and material properties for a stiffened plate under uniaxial tension. Numerical results involving the stress intensity factors and the strain energy release rate are presented. The closed-form expressions for the Fredholm kernels are provided to obtain the solution for an arbitrary geometry and material properties. For the general geometry, the contribution of the normal stress is quite significant, while for symmetric geometries, the shear stress is dominant, the normal stress vanishes if the adherends are of the same material and the same thickness