169 research outputs found
Different Arguments for and Against the Role and Impact of Foreign Investment on The Development Potentials of Developing Countries: An Overview
This study explores different arguments for and against the role of foreign investment on the development potentials of developing countries. Generally, foreign investment comes to host countries through transnational corporatios (TNCs). These corporations are global profit-seeking organisations, investing in more than one country and supplying financial capital, management, technology and marketing enterprise. The arguments for and against the role and impact of foreign investment focus mainly on the following areas: economic growth, technology transfer, balance of payments, export performance, employment, environment, and transfer pricing as well as socio-cultural aspects of TNCs. The study concludes that with the appropriate government policies, such as unbiased trade regime, market reform and cooperation, developing countries could provide more benefits from foreign investment
First-principles investigation of graphitic nanostructures
Ankara : The Department of Physics and the Graduate School of Engineering and Science of Bilkent University, 2013.Thesis (Ph. D.) -- Bilkent University, 2013.Includes bibliographical references leaves 103-120.In this thesis, first-principles investigations of several graphene related nanosystems
based on density functional theory are presented. First, the electronic
structure of several graphene nano-ribbons both in 1D and 0D (up to systems
with more than 1000 atoms) including all types (armchair, zigzag and chiral) are
discussed using tight binding calculations. We observed that the band gap of
the ribbons depend both on the length of the ribbon and the angle of chirality.
Second, the effect of phosphorus and sulfur during the growth of carbon nanotubes
is investigated from ab-initio density functional theory based calculations.
To this end, we present the binding chemistry of phosphorus and sulfur atoms
on graphene with and without vacancies and kink like defect structures. Consequently,
the difference between the bindings of these two atoms is discussed in
order to understand the reason behind their effects on the growth mechanism.
The details of the phosphorus or sulfur binding are important in order to understand
the occurrence of Y-junctions and kinks in carbon nanotubes as well.
Third, we focus on the interaction of bilayer graphite and multi-walled carbon
nanotubes with the Li atom since these materials are prime candidates for the
electrodes for battery applications. The need for rechargeable batteries with
high capacity increased enormously by the invention of electronic devices like cell
phones or MP3 players. Hence, there is a huge effort to develop and improve
Li-ion batteries. Therefore, we have investigated interaction of Li with graphene
and Li intercalation to bilayer graphene and multi-walled carbon nanotubes from
planewave pseudo potential calculations. Finally, super-periodic graphitic structures
observed through scanning tunnelling microscope are described and investigated
from density functional calculations. The difference between the observed
and actual periodicity and the occurrence of the so-called Moire patterns are
explained in terms of geometrical calculations and the charge density of these
systems.Şen, Hüseyin ŞenerPh.D
Electronic structure of graphene nano-ribbons
Ankara : The Department of Physics and the Institute of Engineering and Science of Bilkent Univ., 2008.Thesis (Master's) -- Bilkent University, 2008.Includes bibliographical references leaves 51-54.Graphite is a known material to human kind for centuries as the lead of a pencil.
Graphene as a two dimensional material, is the single layer of graphite. Many
theoretical works have been done about it so far, however, it newer took attention
as it takes nowadays. In 2004, Novoselov et al. was able to produce graphene
in 2D. Now that, making experiments on graphene is possible scientists have
to renew their theoretical knowledge about systems in two dimension because
graphene, due to its electronic structure, is able to prove the ideas in quantum
relativistic phenomena. Indeed, recent theoretical studies were able to show that,
electrons and holes behave as if they are massless fermions moving at a speed
about 106m/s (c/300, c being speed of light) due to the linear electronic band
dispersion near K points in the brillouin zone which was observed experimentally
as well.
Having zero band gap, graphene cannot be used directly in applications as
a semiconductor. Graphene Nano-Ribbons (GNRs) are finite sized graphenes.
They can have band gaps differing from graphene, so they are one of the new candidates
for band gap engineering applications such as field effect transistors. This
work presents theoretical calculation of the band structures of Graphene NanoRibbons
in both one (infinite in one dimension) and zero dimensions (finite in both
dimensions) with the help of tight binding method. The calculations were made
for Zigzag, Armchair and Chiral Graphene Nano-Ribbons (ZGNR,AGNR,CGNR)
in both 1D and 0D. Graphene nano-ribbons with zero band gap (ZGNR and
AGNR) are observed in the calculations as well as the ribbons with finite band
gaps (AGNR and CGNR) which increase with the decrease in the size of the
ribbon making them much more suitable and strong candidate to replace silicon
as a semiconductor.Şen, Hüseyin ŞenerM.S
The relative effectiveness of Monetary and Fiscal Policies on growth: what does long-run SVAR model tell us?
This paper studies empirically the relative effectiveness of monetary and fiscal policies on growth. Unlike many previous papers which have focused, to a large extent, on the effect of monetary or fiscal policies separately, this paper considers the comparative efficacy of the two policies on growth by applying the Structural Vector Autoregression (SVAR) model to the quarterly data for Turkey over the period 2001:Q1-2014:Q2. The empirical findings of this paper show that both monetary and fiscal policies do have significant effects on growth. However, monetary policy is more effective than fiscal policy in stimulating growth. More specifically, interest rate ―a monetary policy variable― is the most potent instrument in affecting growth. Then budget deficit ―a fiscal policy variable― becomes the second important variable after interest rate. These findings suggest that although the relative effectiveness in boosting growth is different, both policies significantly affect growth, suggesting that they should be used jointly but in an efficient manner
Growth enhancing effect of discretionary fiscal policy shocks: Keynesian, Weak Keynesian or Non-Keynesian?
Using the extended version of the Blanchard and Perotti SVAR technique, this paper attempts to empirically predict the growth enhancing effect of discretionary fiscal policy shocks in both short- and long-run in Turkey over the period 2006:Q1-2015:Q1. Unlike previous studies which have mainly focused on fiscal policy instruments - taxes and government spending - at the aggregate level, this paper considers these instruments at the component level, and then attempts to analyze comparatively the effect of changes in each component on growth. The findings of the paper show that growth enhancing effect of discretionary fiscal policy shocks varies according to its components. However, discretionary fiscal policy shocks at the component level indicate mixed results. In the short-run, only the shocks to government spending have a Keynesian effect. In all other cases, discretionary fiscal policy shocks seem to capture a weak Keynesian and/or non-Keynesian effect in the case of Turkey
Taxes and Private Consumption Expenditure: A Component Based Analysis for Turkey
The purpose of this paper is to analyze empirically the short- and long-run effects of tax shocks on private consumption expenditure on component basis in Turkey. To do so, first, we decomposed private consumption expenditure into four major sub-categories, including food, education, and transportation, among others. And then, we employed a Structural VAR (SVAR) model which was calibrated to quarterly data set for the period 2003:Q1-2013:Q3.
Specifically, our empirical findings show that the effects of tax shocks on the components of private consumption expenditure differ in the short- and long-run. In the short-run, all the taxes which we considered have a significant effect on the components of private consumption expenditure, whereas in the long-run only two taxes - the VAT and the personal income tax - affect it. However, it is important to highlight that the components of private consumption expenditure are much more affected by the VAT in the both short- and long-run. In brief, the findings reveal that the effects of tax shocks on private consumption expenditure shows difference, changing according to sorts of taxes, components of the expenditure, and the length of period
The relative effectiveness of Monetary and Fiscal Policies on growth: what does long-run SVAR model tell us?
This paper studies empirically the relative effectiveness of monetary and fiscal policies on growth. Unlike many previous papers which have focused, to a large extent, on the effect of monetary or fiscal policies separately, this paper considers the comparative efficacy of the two policies on growth by applying the Structural Vector Autoregression (SVAR) model to the quarterly data for Turkey over the period 2001:Q1-2014:Q2. The empirical findings of this paper show that both monetary and fiscal policies do have significant effects on growth. However, monetary policy is more effective than fiscal policy in stimulating growth. More specifically, interest rate ―a monetary policy variable― is the most potent instrument in affecting growth. Then budget deficit ―a fiscal policy variable― becomes the second important variable after interest rate. These findings suggest that although the relative effectiveness in boosting growth is different, both policies significantly affect growth, suggesting that they should be used jointly but in an efficient manner
Genotoxic, carcinogenic potential of food additives and their other effects on human healthGıda katkı maddelerinin genotoksik, karsinojenik potansiyeli ve insan sağlığı üzerindeki diğer etkileri
The use of food additives (FAs) in food production has become an indispensable part of food technology primarily in developed countries for the last 30 years. Today, we encounter with chemical or E coded names of FAs in the ingredients written on the packages of many food products; from take-home foods to frozen products and canned goods. Some of these products, which have been increasing in terms of usage and number each passing day, have detected genotoxic and carcinogenic effects with various toxicological test systems. Besides, some of these are emerged to play role in the formation of hyperactivity, allergy, neurodegenerative diseases, obesity, diabetes, reproduction and gastrointestinal system disorders. In this review, it is aimed to give information about food additives which have been determined to have genotoxic and carcinogenic effects and reported to cause other health risks with toxicological studies. Extended English abstract is in the end of PDF (TURKISH) file. ÖzetSon 30 yıldır gelişmiş ülkeler başta olmak üzere, gıda üretiminde katkı maddelerinin kullanımı gıda teknolojisinin vazgeçilmez bir parçası olmuştur. Günümüzde, hazır gıdalardan, dondurulmuş ürünlere ve konservelere kadar tükettiğimiz birçok gıda maddesinin ambalajlarındaki içindekiler kısmında gıda katkı maddelerinin kimyasal yada E kodlu isimleri ile karşı karşıya gelmekteyiz. Kullanımları ve sayıları her geçen gün artan bu maddelerin bazılarının genotoksik ve karsinojenik etkili olduğu çeşitli toksikolojik test sistemleriyle belirlenmiştir. Ayrıca bazılarının hiperaktivite, alerji, nörodejeneratif hastalıklar, obezite, diyabet, üreme ve gastrointestinal sisteme ilişkin bozuklukların oluşumunda rol oynadığı da ortaya çıkmıştır. Bu derlemede, toksikolojik çalışmalarla genotoksik, karsinojenik etkilere sahip olduğu ve diğer sağlık risklerine yol açtığı belirlenen gıda katkı maddeleri hakkında bilgi verilmesi amaçlanmıştır
The importance of genotoxicity tests in new drug development processGenotoksisite testlerinin yeni ilaç geliştirme sürecindeki önemi
In the preclinic investigation period at the beginning of the drug development process, it is an obligation to subject candidate drugs to genotoxicty investigations. Genotoxicty data of drugs that are developed with these tests are demanded as a part of the security evaluation process by regulatory authorities in various countries. The demand of these laboring and costly data by regulatory authorities of various countries in different standards prevents potential candidate drugs from being marketed, interrupts the drug development process and causes unnecessary utilization of experimental materials in researches. Therefore, nowadays, it is generally accepted that the researches aimed at achieving these data are implemented with standardized approaches in the guidelines of international harmonisation organizations such as ICH (International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use) and OECD (Organisation for Economic Cooperation and Development). In this review, it is aimed to provide current information about the various genotoxicity tests which are used commonly in the drug development process, in accordance with ICH, OECD guidelines and literature. Extended English summary is in the end of Full Text PDF (TURKISH) file.Özetİlaç geliştirme sürecinin başlangıcındaki preklinik araştırma döneminde, aday ilaçların genotoksisite testlerinden geçirilmesi bir zorunluluktur. Bu testlerle elde edilen genotoksisite verileri, çeşitli ülkelerdeki düzenleyici otoriteler tarafından güvenlilik değerlendirme sürecinin bir parçası olarak istenmektedir. Elde edilmesi oldukça zahmetli ve maliyetli olan bu bilgilerin, farklı ülkelerin düzenleyici otoriteleri tarafından değişik standartlarda istenmesi, potansiyel ilaç adaylarının pazarlamasını engellemekte, ilaç geliştirme sürecini kesintiye uğratmakta ve araştırmalarda gereksiz yere deney materyali kullanımına neden olmaktadır. Bu bakımdan, günümüzde bu bilgileri elde etmeyi amaçlayan araştırmaların, ICH (İnsanda Kullanılan İlaçların Ruhsatlandırılması İçin Teknik Gerekliliklerin Uyumlandırılması Uluslararası Birliği) ve OECD (Ekonomik Kalkınma ve İşbirliği Örgütü) gibi uluslararası harmonizasyon örgütlerinin kılavuzlarında standardize edilen yaklaşımlarla uygulanması genel kabul görmektedir. Bu derlemede, ilaç geliştirme sürecinde kullanılan genotoksisite testlerine ilişkin, ICH, OECD kılavuzları ve literatür ışığında güncel bilgiler verilmesi amaçlanmıştır
Investigation of factors predicting job satisfaction of school counsellors in Turkey
Job satisfaction can be defined as individuals' perceptions of satisfaction towards their profession. This concept
is also considered to be important for the school counselling profession because school counsellors’ high level
of job satisfaction is assumed to have positive effects not only on them but also on their students and
accordingly on the education system. Therefore, it is thought that it is important to examine the factors that
predict job satisfaction of school counsellors. For this purpose, this study was conducted on 194 (female=145
and male=49) school counsellors in Turkey. As a result of the research, it was determined that there was a
significant positive relationship between school counsellors’ job satisfaction and professional self-esteem. In
addition, job satisfaction of school counsellors working in the private sector was found to be higher than those
working in the public sector. It was found that job satisfaction of school counsellors did not differ significantly
according to gender, age and school level variables
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