Quasi-Experimental Impact Estimates of Immigrant Labor Supply Shocks: The Role of Treatment and Comparison Group Matching and Relative Skill Composition

This paper examines the employment effects of an increase in labor supply using the politically-driven exodus of ethnic Turks from Bulgaria into Turkey in 1989. The strong involvement of the Turkish state in the settlement of earlier waves of repatriates provides us a strong source of exogenous variation in the 1989 immigrant shock across locations. Using a potential sample of 613 cities and towns in Turkey with variable treatment intensity - in some locations the change in the labor force is almost 10 percent - this analysis places much attention on constructing a matched sample that is well balanced in terms of covariate distributions of the treatment and comparison groups, including matching based on an estimated propensity score. We find a positive effect of repatriates on the unemployment of non-repatriates. In fact, in certain regions, a 10-percentage-point increase in the share of repatriates in the labor force increases the unemployment rate of natives by 4 percentage points. When the analysis is done according to skill groups, we find that the impact is the strongest on the young and on non-repatriates with similar educational attainment.Labor Force and Employment, Immigrant Workers, Quasi experiments

Investigation of delayed fluorescence phenomena in conjugated molecules using time-resolved laser spectroscopy

This thesis reports structure-property relationships in a range of conjugated molecules where the nature of the delayed fluorescence (DF) is used as a powerful diagnostic tool in order to gain insight into the nature of the molecules. All the investigations revolve around using three spectroscopic methods; steady state, single-photon counting and particularly time-resolved nanosecond spectroscopy. The rarely observed optically generated geminate electron-hole (e-h) pair recombination is designated as the origin of DF in Rhodamine 6G and its derivative ATTO-532 molecules. The DF shows a strong dependence on excitation energy, which is due to emission arising from higher energy excited dimeric states. In addition, the complex excited-state nature of the polyspirobifluorene (PSBF) polymer is investigated in both dilute solutions and spin-coated films. According to investigations carried out in dilute solutions, solvent polarity and temperature dependent charge transfer (CT) state formation is observed as arising from the “inter/intrachain” interaction phenomena. The stabilisation of the intra- CT state at low temperatures exhibits the presence of both triplet-triplet annihilation (TTA) and monomolecular processes. These findings are used to interpret the up-conversion data of PSBF in thin films, clearly revealing that both TTA and thermally activated delayed fluorescence (TADF) are involved in indirect singlet generation. The same mixed contribution is also confirmed in anthracene based, small molecule, thin films. Consequentially, these findings highlight the investigated system as one of the desirable alternative molecular systems through which high efficiencies in organic light emitting device (OLED) applications can be attained. Finally, an understanding of novel anthracene based novel acceptor molecule is developed through the use of a sensitizer based up-conversion experimental method, in which the question of how the side groups (having different electron affinities) affect the TTA efficiency and triplet energy transfer efficiency is clarified. Lastly, the investigations show that novel pyridine derivatives have solvent polarity and viscosity dependent excited state configurations, which are designated as twisted/wagged intramolecular charge transfer states. The DF, in this case, predominantly originates from monomolecular recombination of the geminately bound e-h pairs. It is believed that this can be a major loss mechanism for quantum yield in ICT systems. Murat Aydemir, August, 201

Next-Generation Infrastructure and Technology Issues in 5G Systems

Next-generation technologies are being tried to develop for 5G wireless cellular networks nowadays by many researchers. Some key technologies provide significant improvements for 5G systems in terms of huge capacity, higher data rate, signaling overhead on the network and energy-spectral efficiency. But these technologies also bring along critical issues for 5G systems. In this paper, these major problems of 5G networks are discussed in terms of scarcity radio frequency spectrum, inter-antenna synchronization, antenna deployments in cells, network and traffic management, cost and workload. Also these challenges are expressed, presented and discussed in each section to provide prior knowledge and perspective for 5G network designers and researchers

Next-Generation Infrastructure and Technology Issues in 5G Systems

Next-generation technologies are being tried to develop for 5G wireless cellular networks nowadays by many researchers. Some key technologies provide significant improvements for 5G systems in terms of huge capacity, higher data rate, signaling overhead on the network and energy-spectral efficiency. But these technologies also bring along critical issues for 5G systems. In this paper, these major problems of 5G networks are discussed in terms of scarcity radio frequency spectrum, inter-antenna synchronization, antenna deployments in cells, network and traffic management, cost and workload. Also these challenges are expressed, presented and discussed in each section to provide prior knowledge and perspective for 5G network designers and researchers

Estimates of the Return to Schooling in a Developing Country: Evidence from a Major Policy Reform in Turkey

This paper uses a major change in the compulsory schooling policy in Turkey – which increased the mandatory duration from five to eight years -- to estimate the causal effect of education on earnings. The policy reform brought about a substantial rise in schooling attainment due to the high dropout rates at the end of compulsory schooling, the duration of extension, as well as the spillover effects of the policy on non-compulsory schooling years. Our results show that the 2SLS estimates of the returns to education are much larger estimates than the OLS estimates. These results also constitute the first causal estimates of the returns to education in the Turkish context and one of the few in developing country contexts

Quasi-experimental impact estimates of immigrant labor supply shocks: the role of treatment and comparison group matching and relative skill composition

This paper examines the employment effects of an increase in labor supply using the politically-driven exodus of ethnic Turks from Bulgaria into Turkey in 1989. The strong involvement of the Turkish state in the settlement of earlier waves of repatriates provides us a strong source of exogenous variation in the 1989 immigrant shock across locations. Using a potential sample of 613 cities and towns in Turkey with variable treatment intensity—in some locations the change in the labor force is almost 10 percent—this analysis places much attention on constructing a matched sample that is well balanced in terms of covariate distributions of the treatment and comparison groups, including matching based on an estimated propensity score. We find a positive effect of repatriates on the unemployment of non-repatriates. In fact, in certain regions, a 10-percentage-point increase in the share of repatriates in the labor force increases the unemployment rate of natives by 4 percentage points. When the analysis is done according to skill groups, we find that the impact is the strongest on the young and on non-repatriates with similar educational attainment

Quasi-experimental impact estimates of immigrant labor supply shocks: the role of treatment and comparison group matching and relative skill composition

This paper examines the employment effects of an increase in labor supply using the politically-driven exodus of ethnic Turks from Bulgaria into Turkey in 1989. The strong involvement of the Turkish state in the settlement of earlier waves of repatriates provides us a strong source of exogenous variation in the 1989 immigrant shock across locations. Using a potential sample of 613 cities and towns in Turkey with variable treatment intensity—in some locations the change in the labor force is almost 10 percent—this analysis places much attention on constructing a matched sample that is well balanced in terms of covariate distributions of the treatment and comparison groups, including matching based on an estimated propensity score. We find a positive effect of repatriates on the unemployment of non-repatriates. In fact, in certain regions, a 10-percentage-point increase in the share of repatriates in the labor force increases the unemployment rate of natives by 4 percentage points. When the analysis is done according to skill groups, we find that the impact is the strongest on the young and on non-repatriates with similar educational attainment

Unilaterally posterior lumbar interbody fusion with double expandable peek cages without pedicle screw support for lumbar disc herniation

Objectives Posterior lumbar interbody fusion (PLIF) is usually bilateral procedure, and it is combined with posterior by bilateral pedicle screw support or with fixation. The purpose of this retrospective study was to compare the surgical outcomes of simple discectomy and PLIF without pedicle screw support in patients with lumbar disc herniation (LDH). Patients and methods 60 patients with single segment LDH were operated between February 2010 and June 2013. 40 patients were treated with simple discectomy (Group 1) and 20 patients were treated with PLIF using double expandable polyetheretherketone (PEEK) cages without instrumentation (Group 2) unilaterally. Pain and function were evaluated by the visual analog scale (VAS) and Oswestry disability index (ODI) before and 18 months after surgery. Besides, PLIF patients were evaluated with computerized tomography (CT) scan of lumbar vertebra for the evaluation of the height of the disc, instability and fusion. Results Both leg and low back pain VAS scores were significantly improved 18 months after surgery in both of the groups (p<0.001). Significant decrease in VAS low back pain scores was seen in group 2 when compared to group 1 (p<0.001). Height of the intervertebral disc space was preserved and no instability was detected in group 2. No recurrence and 80% fusion rate was achieved in group 2. Conclusion This study showed that unilateral PLIF intervention with double expandable PEEK cages without pedicle screw support would be sufficient in the management of single segment lumbar disc herniation in patients whom are thought to have lumbar stabilization

Effect of Initial Configuration on DFT Calculations for Transition Metal Complexes

Computational methods, which solves the Schrödinger’s equation for molecules, have become an indispensable tool in last decades. And Density Functional Theory is one of the most used, and most effective computational method. Transition Metal complexes, on the other hand, have been being used extensively in many important applications in many fields, such as chemical catalysts, atomic thin films, and pharmaceutical industry. Applying computational methods to transition metal complexes has become inevitable to understand better, to control and to design these compounds. As it is known, it is very difficult to handle transition metals computationally, mostly due to near degeneracy in their electronic states. The computational algorithms usually cannot achieve as successive result as they can do for other typical elements, like carbon or nitrogen for instance. Computational methods are needed to be improved for properly deal with transition metal complexes. To find computationally cheaper but still effective methods to deal with these complexes is a major challenge. Unlike the analogue calculations, computational methods solve all equations iteratively, so there are major differences between these two calculation types. The starting point in state space (the assumed initial conformation of molecule) is could have a stronger effect then the expected, on the flow of the iterative solving algorithm of the computational approach. Here we present a comparative study for a Ruthenium complex. We have optimised the molecule several times. Each of the optimisations started from different initial molecular conformations. Then we have compared the result in different ways, like calculation times and minimum energy that had reached, to see effect of starting configurations on the calculation. It is showed that, starting configuration is an important parameter for computational calculations of transition metal complexes, and it is needed to be carefully chosen to improve success of calculations

Coexistence of cervico-thoracic extradural en-plaque meningioma with multiple intracranial meningiomas

Meningioma is one of the most common tumors in the spinal cord. Extradural and en-plaque variety of meningioma occur less frequently. A 47-year-old woman is presented with radiculopathy signs. Magnetic resonance imaging revealed a lesion from C6 through T3 vertebral levels compressing the cord both anteriorly and posteriorly. Subtotally excision was performed and histopathologic signs showed transitional type of meningioma (WHO Grade 1). Post operatively, she had good neurological recovery. Intraoperative findings point out that the en-plaque meningioma was pure extradural. Twelve cases of pure extradural en-plaque meningioma have been reported in the literature. Besides, to the best our knowledge coexistence of “en plaque” spinal epidural meningioma with meningiomas in cranial cavity has not been reported. Complete resection is mandatory to prevent recurrence. Moreover, it is considerably difficult to remove the parts of tumor over anterior of the dura without complication