Impact of global climate change on agricultural production: Balkan countries in 2050

The occurrence of extreme weather events due to today’s climate change is having a significant impact on agriculture. The purpose of this study is to estimate the possible effects of global climate change on agriculture at a regional level. To this end, the Global trade analyses project (GTAP) model has been used to examine the possible effects of climate change on agricultural production in Turkey, Romania, Bulgaria, Greece, and other Balkan countries for 2050. GTAP analysis data is compiled from the GTAP database, which includes 6 regions and 33 sectors. It has been calculated that climate change will have negative effects on the gross domestic product (GDP) of Balkan countries. The negative impact of global climate change on crop yields is predicted to reduce the competitiveness of Balkan countries in the foreign trade of agricultural products. © 2020, Scibulcom Ltd.. All rights reserved

Diurnal gradual heat stress affects antioxidant enzymes, proline accumulation and some physiological components in cotton (Gossypium hirsutum L.)

Even though high temperatures significantly reduce both vegetative growth and yield in cotton, very little is known about the effects of heat stress on cotton antioxidant system. Thus, the effects of gradual heat stress on cotton growth in controlled conditions were investigated in the present study. At squaring stage, cotton plants were subjected to two different temperatures, 38 and 45°C to determine the influence of heat stress on the plants. The results of the present study showed that heat stress did not significantly altered the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in the leaves, whereas there was a remarkable decline in proline quantity of the leaves of plants subjected to 45°C heat stress. As for the amount of total chlorophyll content, a slight increase at plants treated with 38°C temperature was observed. Furthermore, the activities of some enzymes such as superoxide dismutase (SOD), which were associated with heat stress response in other plants was also investigated. For example, there was decline in the activitity of SOD in the plants exposed to high temperatures. On the contrary, catalase (CAT) activity increased at 45°C; peroxidase (POX) activity increased at 38°C and ascorbate peroxidase (APX) activity increased at 38 and 45°C. The results from this study suggest a potential role for CAT, POX and APX in the reduction of elevated levels of H2O2 in cotton plants grown under heat stress condition. To sum up, it could be concluded that, diurnal gradual heat stress caused a low oxidative injury in cotton

1-[2-(2,4-Dichloro­benz­yloxy)-2-phenyl­ethyl]-1H-1,2,4-triazole

In the mol­ecule of the title compound, C17H15Cl2N3O, the triazole ring is oriented at dihedral angles of 9.24 (6) and 82.49 (6)°, respectively, with respect to the phenyl and dichloro­benzene rings. The dihedral angle between the dichloro­benzene and phenyl rings is 88.57 (5)°. An intra­molecular C—H⋯O contact results in the formation of a planar five-membered ring

Determination of Arsenic, Mercury and Barium in herbarium mount paper using dynamic ultrasound-assisted extraction prior to atomic fluorescence and absorption spectrometry

A dynamic ultrasound-assisted extraction method using Atomic Absorption and Atomic Flourescence spectrometers as detectors was developed to analyse mercury, arsenic and barium from herbarium mount paper originating from the herbarium collection of the National Museum of Wales. The variables influencing extraction were optimised by a multivariate approach. The optimal conditions were found to be 1% HNO3 extractant solution used at a flow rate of 1 mL min-1. The duty cycle and amplitude of the ultrasonic probe was found to be 50% in both cases with an ultrasound power of 400 W. The optimal distance between the probe and the top face of the extraction chamber was found to be 0 cm. Under these conditions the time required for complete extraction of the three analytes was 25 min. Cold vapour and hydride generation coupled to atomic fluorescence spectrometry was utilized to determine mercury and arsenic, respectively. The chemical and instrumental conditions were optimized to provide detection limits of 0.01ng g-1 and 1.25 ng g-1 for mercury and arsenic, respectively. Barium was determined by graphite-furnace atomic absorption spectrometry, with a detection limit of 25 ng g-1. By using 0.5 g of sample, the concentrations of the target analytes varied for the different types of paper and ranged between 0.4–2.55 µg g-1 for Ba, 0.035–10.47 µg g-1 for As and 0.0046–2.37 µg g-1 for Hg

Determinants of intraregional migration in Sub-Saharan Africa 1980-2000

Despite great accomplishments in the migration literature, the determinants of South-South migration remain poorly understood. In an attempt to fill this gap, this paper formulates and tests an empirical model for intraregional migration in sub-Saharan Africa within an extended human capital framework, taking into account spatial interaction. Using bilateral panel data between 1980 and 2000, we find that intraregional migration on the subcontinent is predominantly driven by economic opportunities and sociopolitics in the host country, facilitated by geographical proximity. The role played by network effects and environmental conditions is also apparent. Finally, origin and destination spatial dependence should definitely not be ignored

Polarization insensitive single mode Al2O3 rib waveguide design for applications in active and passive optical waveguides

Both passive and active, single mode, wavelength and polarization insensitive design of Al2O3 rib waveguides on SiO2 substrate is reported. Influence of the waveguide height, etch depth, waveguide width and operation wavelength to the mode number, mode size, birefringence and polarization sensitivity were analyzed with Beam Propagation Method. Design parameters for targeted properties are computed for waveguide widths ranging from 0 to 10 µm, and for etch depth ranging from 0 to 0.5 µm for fixed waveguide height of 0.5 µm. A design window for a fixed width of 3.5 µm and etch depths between 0.325 to 0.375 µm is identified for single mode, wavelength and polarization insensitive operation of Al2O3 waveguides on thermal oxide. A novel rib TE mode selective filter design is also suggested as an output of the numerical simulations

Öğretmen Adaylarının Çevrimiçi ve Geleneksel Bilgisayar okuryazarlığı Derslerinde Bilgisayara Yönelik Tutumlarının Karşılaştırılması: Bir Durum Çalışması

This study examined the effect of two computer literacy courses at METU, (one offered on-line and the other given by traditional methods. These two courses were compared in terms of their effectiveness on the attitudes of the student-teachers towards computers. Different demographics such as gender, whether any computer-related courses had been taken before, previous computer attitude, and possession of a home computer were taken into consideration. This study also explored the other factors that contributed to changes in attitudes of the student teachers. The study used data from 209 (147 female, 62 male) student-teachers of which 69 attended the on-line computer literacy course IS100 "Introduction to Information Technology and Applications", and 140 attended the traditional computer literacy course SCE300. "Computer Applications in Education", which were offered at the Middle East Technical University (METU) in Turkey.Results of Multiple Regression Analysis indicated that there is a combined effect of gender, computer literacy course type (traditional vs on-line), whether any computer related course had been taken before, previous computer attitude and possession of home computer on student-teachers' post-attitude toward computers. The follow-up study results also supported the results of statistical the analysis, and they investigated student teachers' perceptions about the computer literacy course they attended.Bu çalışmanın amacı, Orta Doğu Teknik Üniversitesi (ODTÜ)'nde çevrimiçi (on-line) olarak yürütülen IS 100 kodlu 'Bilişim Teknolojileri ve Uygulamalarına Giriş' dersi ile geleneksel yöntemlerle yürütülen SCE 300 kodlu 'Eğitimde Bilgisayar Uygulamaları' dersinin öğretmen adaylarının bilgisayara yönelik tutumları üzerindeki etkilerini incelemektir. Çalışmada, öğrencilerin cinsiyet, daha önce bilgisayar dersi alıp almadıkları, dersi almadan önceki bilgisayara yönelik tutumları ve evde bir bilgisayarları olup olmadığı gibi faktörler de göz önünde tutulmuştur Ayrıca, öğrencilerin bilgisayara yönelik tutumlarını başka ne gibi faktörlerin etkilediği niteliksel olarak da araştırılmıştır. Veriler 147'si kız, 62'si erkek, toplam 209 öğretmen adayı öğrenciden toplanmıştır. Bunlardan 69'u çevrimiçi (ISIOO-Bilişim Teknolojileri ve Uygulamalarına Giriş), 140'ı ise geleneksel yöntemlerle verilen (SCE300-Eğitimde Bilgisayar Uygulamaları) bilgisayar okuryazarlığı derslerine katılmıştır. Çok yönlü regrasyon sonuçları, cinsiyet, alman bilgisayar dersinin çeşidi (geleneksel ya da çevrimiçi), daha önce bilgisayarla ilgili derslerin alınıp alınmaması, dersi almadan önceki bilgisayara yönelik tutumları ve evde bilgisayar olup olmaması gibi faktörlerin öğrencilerin ders sonrası tutumları üzerinde birleşik etkisi olduğunu göstermiştir. Niteliksel çalışmanın sonuçları ise istatistiksel sonuçları desteklemiş ve öğrencilerin devam ettikleri bilgisayar dersi ile ilgili düşünce ve görüşlerini analiz etmiştir

Üniversite Öğrencilerinin Osmoz ve Difüzyon Konularındaki Kavram Yanılgıları

The aim of the study is to determine the major and non-major biology students’ understanding of the concepts of diffusion and osmosis and to identify the points at which they have misconceptions by using a two-tier diagnostic test developed by Odom and Barrow (1995). The test, consisting of 12 multiple choice questions, was administered to 135 university students (79 majors and 56 non-majors). Each item was analyzed to determine the students’ understanding of, and identify their misconceptions about, diffusion and osmosis. For the first tier of the test, the range of correct answers was 53%-95% for the major and 42.7%-100% for the non-major biology students. However, when both tiers were combined this range was reduced to 27.8% - 88.6% for majors and 19.6% - 67.8% for non-majors. Analysis of the results revealed that neither major nor non-major students acquired a satisfactory understanding of these concepts and that they had a considerable degree of misconceptions concerning diffusion and osmosis.Bu çalışma, genel biyoloji dersini zorunlu ve seçmeli olarak alan üniversite öğrencilerinin difüzyon ve osmoz konularını ne derecede anladıklarını ve hangi noktalarda kavram yanılgılarına düştüklerini araştırmak amacıyla yapılmıştır. Kavram yanılgıları Odom ve Barrow (1995) tarafından geliştirilen ve 12 adet çoktan seçmeli sorudan oluşan iki aşamalı tanı testi kullanılarak saptanmıştır. Bu test, 79’u genel biyoloji dersini zorunlu ve 56’sı seçmeli olarak alan toplam 135 üniversite öğrencisine uygulanmıştır. Testin ilk aşaması için, doğru yanıt aralığı genel biyoloji dersini zorunlu olarak alan öğrencilerde %53 - %94.4 ve seçmeli olarak alan öğrencilerde %42.7 - %100’dür. Ancak her iki aşama birleştirildiğinde bu aralığın dersi zorunlu alanlarda %27.8 - %88.6’ya ve seçmeli alanlarda %19.6 - %67.8’e düştüğü gözlemlenmiştir. Bu sonuçlar, araştırmaya katılan öğrencilerin konuyu yeterince anlamadıklarını ve kavram yanılgılarına sahip olduğunu göstermektedir