Underpricing in Turkey: Comparison of the IPO Methods

This paper addresses the question of what kind of selling and underwriting procedure might be preferred for controlling the amount and volatility of underpricing in the Istanbul Stock Exchange (ISE). Using 1993-2005 firm and issue data, we compare the three substantially different IPO methods available in the ISE. One is very similar to the book building mechanism used in the U.S., another is the fixed price offer, and the third one is the sale through the stock exchange method. The empirical analysis reveals significant first day underpricing of 7.01% in fixed price offer, 11.47% in book building mechanism, and 15.68% in sale through the stock exchange method. Finally, we also show that fixed price offers can better control the impact of market information on underpricing than sale through the stock exchange methodipo, book building, fixed price offer, istanbul stock exchange, emerging market

Isovector axial-vector form factors of octet baryons in QCD

We compute the diagonal isovector axial-vector as well as induced pseudoscalar form factors of nucleon, $\Sigma$ and $\Xi$ baryons by employing the light-cone QCD sum rules to leading order in QCD and including distribution amplitudes up to twist 6. Extrapolating our sum-rules results to low-momentum transfers, we make a comparison with experimental and lattice-QCD results where we can achieve a nice qualitative and quantitative agreement.Comment: 9 pages, 3 figure

Radiative dileptonic decays of B-meson in the general two Higgs doublet model

We investigate the exclusive $B\to \gamma \ell^+ \ell^-$ decay in the general two Higgs doublet model (model III) including the neutral Higgs boson effects with an emphasis on possible CP-violating effects. For this decay, we analyse the dependencies of the forward-backward asymmetry of the lepton pair, $A_{FB}$, CP-violating asymmetry, $A_{CP}$, and the CP-violating asymmetry in forward-backward asymmetry, $A_{CP}(A_{FB})$, on the model parameters and also on the neutral Higgs boson effects. We have found that $A_{FB}\sim 10^{-1}, 10^{-2}$, $A_{CP}\sim 10^{-2}, 10^{-1}$ and $A_{CP}(A_{FB}) \sim 10^{-2}, 10^{-1}$ depending on the relative magnitude of the Yukawa couplings $\bar{\xi}_{N,tt}^{U}$ and $\bar{\xi}_{N,bb}^{D}$ in the model III. We also observe that these physical quantities are sensitive to the model parameters and neutral Higgs boson effects are quite sizable for some values of the coupling $\bar{\xi}_{N,\tau \tau}^{D}$.Comment: 29 pages, 18 eps figures, requires appolb.cls (included

The analysis of Bd−>(η,η′)ℓ+ℓ−B_{d} -> (\eta, \eta^{\prime}) \ell^+ \ell^- decays in the standard model

We study the differential branching ratio, branching ratio and the CP-violating asymmetry for the exclusive $B_{d}->(\eta, \eta^{\prime}) \ell^+ \ell^-$ decays in the standard model. We deduce the $B_{d}->(\eta, \eta^{\prime})$ form factors from the form factors of $B -> \pi$ available in the literature, by using the $SU(3)_F$ symmetry. We observe that these decay modes, which are within the reach of forthcoming B-factories, are very promising to observe CP-violation.Comment: 12 pages, 8 figures, version to appear in Eur.Phys.J.

On the roles of the programmer, the compiler and the runtime system when programming accelerators in OpenMP

OpenMP includes in its latest 4.0 specification the accelerator model. In this paper we present a partial implementation of this specification in the OmpSs programming model developed at the Barcelona Supercomputing Center with the aim of identifying which should be the roles of the programmer, the compiler and the runtime system in order to facilitate the asynchronous execution of tasks in architectures with multiple accelerator devices and processors. The design of OmpSs is highly biassed to delegate most of the decisions to the runtime system, which based on the task graph built at runtime (depend clauses) is able to schedule tasks in a data flow way to the available processors and accelerator devices and orchestrate data transfers and reuse among multiple address spaces. For this reason our implementation is partial, just considering from 4.0 those directives that enable the compiler the generation of the so called “kernels” to be executed on the target device. Several extensions to the current specification are also presented, such as the specification of tasks in “native” CUDA and OpenCL or how to specify the device and data privatization in the target construct. Finally, the paper also discusses some challenges found in code generation and a preliminary performance evaluation with some kernel applications.Peer ReviewedPostprint (author’s final draft

Integrated adaptive approach for reliable multicast transmission over geostationary satellite networks

Multiple retransmission passes, in order to ensure bit-perfect reliability in multicast transmission, results in lower resource utilization and higher session delay. Hence, an integrated adaptive transmission via the use of a cross-layer strategy is proposed in this paper in order to increase forward and return link resource utilization. Specifically, the integration of Channel State Information (CSI) collection policies in the uplink and Channel-Aware Scheduling (CAS) in the downlink is proposed in the face of fluctuating channel conditions observed by multicast terminals. The integration approach can be mathematically represented by suppression error due to the way CSI is collected and suppressed in the return link. Particularly, the suppression error occurs since only a subset of users update their CSI values at any CSI collection instant. In relation to the analytical representation of the suppression error, the performance parameters are then verified via simulation results. From the comparison, it was found that the simulation and analytical results approach agreement at large numbers of terminals. This observation suits the multicast transmission over satellite networks which expect large numbers of terminals over wide coverage

The Contributıon of Wıld Edible Plants to Human Nutrıtion in the Black Sea Regıon of Turkey

Wild edible plants are very widespread in Black Sea Region of Turkey and people have consumed wild edible plants as food and used them for some medicinal purposes due to economical and geographical reasons. In this study, wild edible plants used as food in Ordu and Samsun cities which have the highest population density in Black Sea Region were investigated. In the study area 52 wild edible plants belonging to 26 families were collected from different localities. The highest species numbers were found for Lamiaceae family (10 species). Lamiaceae is followed by Asteraceae (5 species), Apiaceae and Boraginaceae (4 species), Liliaceae (3 species), Orchidaceae and Polygonaceae (2 species)

A Study of the Residual 39Ar Content in Argon from Underground Sources

The discovery of argon from underground sources with significantly less 39Ar than atmospheric argon was an important step in the development of direct-detection dark matter experiments using argon as the active target. We report on the design and operation of a low background detector with a single phase liquid argon target that was built to study the 39Ar content of the underground argon. Underground argon from the Kinder Morgan CO2 plant in Cortez, Colorado was determined to have less than 0.65% of the 39Ar activity in atmospheric argon.Comment: 21 pages, 10 figure