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

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

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

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.

The Effects of Online Professional Development on Teacher Behavior and Perceptions of Science, Technology, Engineering, Art and Math Teaching Efficacy

Background: Research shows that STEAM (science, technology, engineering, arts, and mathematics) curriculum improves student abilities to create relevant products and services. However, teacher support is critical when implementing a new, school-wide curriculum model and learning tools as teachers need easy access to online resources. Yet, online resources currently used in many schools do not inform the processes or the ideology of STEAM curricula through collaboration among all teachers in a private school setting. Purpose: The focus of this quasi-experimental quantitative research study was to examine the impact of a 1-week online STEAM professional development course on teacher behavior and their perceptions of their self-efficacy regarding integrating STEAM concepts in their classroom instruction, lesson plans, and extracurricular activities. The setting was a private school (preschool through Grade 8) with a focus on science and math education in a large Midwestern city. Methods: A quasi-experimental design was selected for this study because of the necessity for data that determine the relationship between the independent variable, which was the STEAM online course developed for the present study, and the dependent variable, which was the teachers\u27 self-reported behavior and perceptions of their STEAM teaching self-efficacy before and after taking the online course. It was also necessary to generate data regarding the relationship between teachers participating in a 1-week online STEAM professional development course and their behavior and perceptions of their self-efficacy regarding STEAM teaching. The participants included elementary and preschool art, math, science, computer, language arts, and social studies teachers at a private school with a focus on science and math education in a large Midwestern city. Results: It was hypothesized that the initiation of a 1-week online STEAM course for teachers would be effective, and pretest/posttest results supported this hypothesis. This is because the intervention combines easy online access to STEAM curricula with the understanding of the importance of the STEAM education model and concepts to all teachers in the private school setting. Conclusion: Study results showed that online professional development participants had an overall positive perception of the effects of the course on their beliefs and perceptions regarding their STEAM curricula teaching self-efficacy. Differences in the pretest and posttest survey results showed that the STEAM online professional development impacted teachers\u27 STEAM teaching self-efficacy

Extraction of cartographic objects in high resolution satellite images for object model generation

The aim of this study is to detect man-made cartographic objects in high-resolution satellite images. New generation satellites offer a sub-metric spatial resolution, in which it is possible (and necessary) to develop methods at object level rather than at pixel level, and to exploit structural features of objects. With this aim, a method to generate structural object models from manually segmented images has been developed. To generate the model from non-segmented images, extraction of the objects from the sample images is required. A hybrid method of extraction (both in terms of input sources and segmentation algorithms) is proposed: A region based segmentation is applied on a 10 meter resolution multi-spectral image. The result is used as marker in a "marker-controlled watershed method using edges" on a 2.5 meter resolution panchromatic image. Very promising results have been obtained even on images where the limits of the target objects are not apparent

The exclusive Bs−>ϕℓ+ℓ−B_s->\phi \ell^+ \ell^- decay in the two Higgs doublet models

We study the differential branching ratio, branching ratio and the forward-backward asymmetry for the exclusive $B_s->\phi \ell^+ \ell^-$ decay in the two Higgs doublet model. We analyze the dependencies of these quantities on the model parameters and show that these observables are highly sensitive to new physics and hence may provide powerful probe of the SM and beyond.Comment: 14 pages, 6 figures, version to appear in Eur.Phys.J.

Influence of Displacement Ductility on Concrete Contribution to Shear Strength

Shear strength of reinforced concrete (RC) members is composed of the contributions of the nominal shear strength provided by transverse reinforcement and concrete. The shear strength of RC members under cyclic lateral loading degrades much faster than the flexural strength. Based on this state, Seismic Codes tend to be excessively conservative and do not take into account the contribution of concrete in certain cases. The aim of this study is to investigate the influence of displacement ductility on concrete contribution to shear strength using finite element analyses (FEA). Based on the agreement between the FEA and experimental results selected from literature, a simple relation is proposed for the prediction of the concrete contribution to shear strength of RC beams. The relation proposed takes into account a reduction of the normalized concrete contribution for increasing inelastic displacement demands, with a small residual strength at large ductility levels

A novel protective barrier for extremity surgeries during the COVID-19 pandemic

Aim: To present a novel protective barrier for COVID-19 transmission and investigate its effectiveness in protection against spreading aerosols and droplets during extremity surgery. Methods: We enrolled 436 patients who underwent urgent and essential surgery on the upper and lower extremity using a novel protective barrier under wide-awake local anesthesia. All patients were investigated in detail for COVID-19 infection with anamnesis, symptom questionnaires, and the required tests before surgery. Patient satisfaction regarding comfort during the surgery behind the protective barrier was analyzed using a five-point Likert scale. The protective effect of the transparent barrier was quantitatively and experimentally analyzed using smoke and saline transmission tests in different clinic scenarios with and without the protective barrier. Results: A total of 345 patients with no signs of COVID-19 infection underwent surgery. Ninety-one suspected patients who had positive COVID-19 symptoms or close contact with a COVID-19 infected patient underwent COVID-19 tests before surgery. All patients underwent urgent surgical treatment on the upper and lower extremities, and easily tolerated and were satisfied with the protective barrier. There was a statistically significant reduction in smoke and saline particles when using the protective barrier (p<0.001). The addition of negative suction and oxygen to the protective barrier potentiated the protective effect (p<0. 001). Conclusions: Extremity surgeries, especially hand surgeries, are one of the most common surgical procedures during the COVID-19 pandemic. Our protective barrier significantly reduced aerosol particles in our experimental model and was successfully used in clinical practice during extremity surgery. &nbsp