Search

Bu araştırmanın amacı, PISA 2009 okuma becerileri testinde kullanılan maddelerin Türkiye-ABD, Türkiye-Birleşik Krallık, ABD-Birleşik Krallık grupları arasında DMF gösterip göstermediğinin incelenmesi, maddelerin olası yanlılık nedenlerinin belirlenmesidir. Bu bağlamda, MH, SIBTEST, MTK temelli MTK-OO ve b parametrelerinin karşılaştırılması yöntemleri kullanılmıştır. Araştırma grubunu, PISA 2009 okuma becerileri testinde dört ve altı numaralı kitapçıkları yanıtlayan Türk öğrenci grubundaki 767, ABD öğrenci grubundaki 796, Birleşik Krallık öğrenci grubundaki 765 öğrenci oluşturmaktadır. DMF belirleme yöntemlerine göre gruplararası DMF gösteren maddelerin, yöntem, madde formatı, metin türü, okurun metne yaklaşımı ve avantaj sağladığı gruba göre dağılımları incelenmiştir. Elde edilen sonuçlara göre, Türk ve ABD?li, Türk ve Birleşik Krallık?taki öğrenci grupları arasında en az altı numaralı kitapçıkta (%31 ve %33) en fazla ise dört numaralı kitapçıkta (%36 ve %49) DMF içeren madde bulunduğunu, DMF içeren maddelerin odak ve referans gruplar arasında dağılımının yaklaşık olarak eşit dağıldığı belirlenmiştir. Madde formatı açısından incelendiğinde, referans grubun lehine gösteren maddelerin çoğunlukla açık uçlu olduğu saptanmıştır. Ayrıca, metne yaklaşım açısından incelendiğinde, çoğunlukla ?bilgiyi bir araya getirme ve yorumlama? yaklaşımına göre geliştirilmiş maddelerin ve metin türü açısından, akıcı metinlerin çoğunlukla referans grubun lehine olduğu saptanmıştır. DMF gösteren maddelerin, sözcüklerin güç anlaşılması, madde formatına aşina olma durumu, çeviri hataları ve kültürel farklılıklardan kaynaklandığı yönünde uzmanlar tarafından ortak görüş bildirilmiştir. Kullanılan DMF belirleme yöntemleri açısından incelendiğinde, SIBTEST ve MTK temelli analizlerin birbirleriyle paralellik gösterdiği, MH yönteminin ise diğer yöntemlere kıyasla daha az sayıda DMF?li madde saptadığı sonucuna ulaşılmıştır.Anahtar Sözcükler: Değişen Madde Fonksiyonu, PISA 2009, Mantel Haenszel, SIBTEST, Madde Tepki Kuramı-Olabilirlik Oran, b parametreleri. The aim of this research is to determine the items indicating differential item functioning (DIF) and its possible sources of bias among Turkey, United States of America (USA) and the United Kingdom (UK) in PISA 2009 reading literacy test. In this context, the methods of Mantel Haenszel (MH), Simultaneous Item Bias Test (SIBTEST), Item Response Theory Likelihood Ratio (IRTLR) and comparison of b parametres have been used. The research group involves 767 pupils from Turkey, 796 pupils from USA and 765 pupils from the UK who answered the questions in Booklet 4 and Booklet 6 of PISA 2009 Reading Test. The distributions of between-groups items indicating DIF in accordance with the DIF method have been investigated with regards to DIF method, item format, text type, aspect and the advantageous group. The results indicate that there are less items with DIF in Booklet 6 (31% and 33%) and there are more items with DIF in Booklet 4 (36% and 49%) between Turkey and USA, Turkey and the UK. Also, the distribution of items with DIF is nearly equal between reference and focal groups. In the context of item format, it has been determined that the items being in favour of reference groups are open-ended. Besides, from the point of text analysis, the items developed with ?integrate and interpret? aspect and ?continuous? texts with regards to text type are mostly also in favour of reference groups. The sources of bias have been identified as hardly understood, being familiar with item format, translation errors and cultural differences by the experts. In terms of DIF methods, SIBTEST and IRT based analyses? results are similar; whereas MH indicates less items with DIF in comparison with other methods.Keywords: Differential Item Functioning, PISA 2009, Mantel Haenszel, SIBTEST, IRT-LR, b parametres. 179

oz ICP-AES İLE ANALİZ EDİLEN SEDİMAN ÖRNEKLERİNİN FARKLI ÖZÜTLEME METOTLARININ ARAŞTIRILMASI Özmen, Deniz Yüksek Lisans, Kimya Bölümü Tez Yöneticisi: Prof. Dr. Semra G. Tuncel Haziran 2001, 145 Sayfa Su kirliliğin en önemli belirleyicilerinden biri olan sediman örneklerinin analizi son zamanlarda büyük önem kazanmıştır. Bu konuda yapılan pek çok çalışma ICP-AES tekniğinin bu tip analizlerde etkili bir şekilde kullanılabileceğini göstermiştir. Analizlerin doğru bir şekilde yapılabilmesi için, uygun analiz tekniğinin seçilmesinin yanısıra örnekleme ve örnek hazırlama gibi aşamalara da büyük önem verilmesi gerekmektedir. Çoğu zaman bu aşamalar analiz sonuçlarında önemli hatalara yol açabilmektedir. Özellikle toprak ve sediman gibi çevresel örneklerin özütlenmesi sırasında, çözünmeme ve elementlerin uçması gibi problemler ortaya çıkabilmektedir. Bu gibi durumlarda olması gerektiğinden düşük sonuçlar elde edilmekte, ve uygun bir özütleme tekniğinin kullanılması gerekmektedir. Yapılan çalışmada, İzmir Körfezinden toplanan 10 sediman örneği ve 3 standart referans maddesi (SRM), Ba, Cu, Ti, La, Sr, Li, Sm, Sc, Cr, Mn, ve Zn, tayini için ICP-AES kullanılarak analiz edilmiştir. Örnekler ve standart referans maddeleri, en uygun asit karışımıyla beraber özütleme tekniğini bulmak amacıyla,asit bombası, açık özütleme ve mikrodalga olmak üzere 3 ayrı teknik ve 2 farklı asit karışımı, HCI+HNO3 ve HF+HNO3, kullanılarak özütlenmiştir. Özütleme teknikleri ve asit karışımları konsantrasyon, tekrarlanabilirlik, örnek/kör çözelti sinyal oranı ve doğruluk olmak üzere çeşitli kriterler için karşılaştırılmıştır. Bu karşılaştırmlar sonucunda, asit bombası tekniği genelde yüksek konsantrasyonlar verdiği halde, özütleme süresi göz önüne alındığında, mikrodalga tekniğinin hemen hemen bütün elementler için en etkili özütleme tekniği olduğu bulunmuştur. Diğer tarafatan, kirlenmeye ve örnek kaybına en çok mağruz kalan açık özütleme tekniğinin en yetersiz teknik olduğu saptanmıştır. Aynı şekilde asit karışımları karşılaştırıldığında, HF+HNO3 karışımının Ba ve Ti için önemli ölçüde daha iyi sonuç verdiği gözlemlenirken, diğer elementler için iki asit karışımının birbirine yakın sonuçlar verdiği gözlemlenmiştir. Anahtar Kelimeler: Özütleme metotları, sediman örnekleri, ICP-AES. vı ABSTRACT INVESTIGA TION OF DIFFERENT DIGESTION METHODS OF SEDIMENT SAMPLES ANAL YSED B Y ICP-AES Özmen, Deniz M.S., Department of Chemistry Supervisor: Prof. Dr. Semra G. Tuncel June 2001, 145 Pages Analysis of sediment samples has a great importance since they are one of the major indicators of water pollution. Among the various analysis techniques inductively coupled plasma atomic emission spectrometry (ICP-AES) has been proved to be a useful and efficient technique that can be used in these analyses. For an accurate analysis, it is also essential to pay attention to sampling and sample preparation steps since they are responsible for the most important errors in an analysis. Especially in the solubilization of environmental samples, some problems may appear due to volatilisation and insolubilization phenomena. In this case, recoveries are poor and it is important to consider a more appropriate solubilization technique. In the present study, ten sediment samples, collected from İzmir Bay, and three standard reference materials (SRM) were analyzed for the determination of Ba, Cu, Ti, La, Sr, Li, Sm, Sc, Cr, Mn, and Zn, by using ICP-AES. The samples and SRMs were digested by three techniques, which are acid-bomb, microwave and open mvessel, and two acid mixtures, HCI+HNO3 and HF+HNO3, to find out the most proper digestion technique together with acid mixture. Digestion techniques and acid mixtures were compared for several criteria, including concentration, precision, sample-to-blank signal ratio and accuracy. At the end of these comparisons it was found that, although acid bomb technique yields higher concentrations in general, when the digestion period is considered, microwave is the most effective digestion technique for almost all of the elements. On the other hand, open vessel technique, which is subject to contaminations and sample loss mostly, was determined to be the poorest one. When acid mixtures were compared in the same way, it was observed that while HF+HNO3 mixture gives significantly better results for Ba and Ti, for rest of the elements two acid mixtures give comparable results. Keywords: Digestion methods, sediment samples, ICP-AES. IV 145

S U M M A R Y The Kingdom of Yugoslavla was founded at the end of the First World War, on December l, 1918. Serbia was the dominant power in the Kingdom comprising ethnically different regions like Serbia, Crotia, Slovenia, Bosnia-Hercegovina and Montenegro. Serbians were repressing the other national groups in the name of the unity of the Kingdom of South Slavs. The Kingdom was an undeveloped and a semi-colonial country with an economy largely dependant on agricultural production. The majority of the peasantry, which constituted the main social segraent of the Yugoslav society, was in great poverty. Further, unegual economic development among the different regions of the country deteriorated the relations among the Yugoslav peoples. The slow pace of industrialisation yielded to a weak working class which was an important social base for the communist movement. Nevertheless, the Yugoslav Cummunist Party gained a limited but firm ground ali över Yugoslavia. The national tensions, political parties with short-sighted policies, failure of the administration in creating a relatively democratic monarchy and the great destitution fell upon the vast majority of the Yugoslavs contributed to the slow but determined progress of the YCP. in the second half of the 1930s, J.B. Tito gained distinction in the ranks of the Party and by putting an end to fractional370 disputes and uniting the Party, formally assumed charge of the Party in January 1939. Encouraged by France, Yugoslavia founded in 1921 the Little Antente with Czechoslovakia and Roumania, in order to protect herself from neighbours like Italy which had territorial claims on her soil. After the assassination of King Alexander in 1934, the rapprochement between France and Italy forced Yugoslavia to seek a `neutrality` policy. But this policy did not prevent the invasion of the country by the German, Italian and Bulgarian armies in 1941. During foreign occupation in the Second World War, two majör resistance movements developed in Yugoslavia. While the Chetniks, under the leadership of Draza Mihajlovic, had the support of the Royal Yugoslav Government in exile in London and for a considerable time that of the Allied Powers, the Partisan movement was organised by the YC'P with the hope of receiving military aid from Soviet Union. in the first years of the war, the Soviet Union officially recognised the Chetniks as the main resistance movement and criticized the Partisans for being openly communist, urged YCP to collaborate with the Chetniks and deplored the formation of the Proletarian Brigades by the YCP. in the course of the resistance struggle when the Partisans gained strength and popularity and when the close relations of the Chetniks with the occupying German army became very much obvious, the Allies shifted their support from Mihajlovic to Tito. The Soviet Union's efforts to restrict the actions of the YCP, belated Soviet military assistanceS U M M A R Y The Kingdom of Yugoslavla was founded at the end of the First World War, on December l, 1918. Serbia was the dominant power in the Kingdom comprising ethnically different regions like Serbia, Crotia, Slovenia, Bosnia-Hercegovina and Montenegro. Serbians were repressing the other national groups in the name of the unity of the Kingdom of South Slavs. The Kingdom was an undeveloped and a semi-colonial country with an economy largely dependant on agricultural production. The majority of the peasantry, which constituted the main social segraent of the Yugoslav society, was in great poverty. Further, unegual economic development among the different regions of the country deteriorated the relations among the Yugoslav peoples. The slow pace of industrialisation yielded to a weak working class which was an important social base for the communist movement. Nevertheless, the Yugoslav Cummunist Party gained a limited but firm ground ali över Yugoslavia. The national tensions, political parties with short-sighted policies, failure of the administration in creating a relatively democratic monarchy and the great destitution fell upon the vast majority of the Yugoslavs contributed to the slow but determined progress of the YCP. in the second half of the 1930s, J.B. Tito gained distinction in the ranks of the Party and by putting an end to fractional370 disputes and uniting the Party, formally assumed charge of the Party in January 1939. Encouraged by France, Yugoslavia founded in 1921 the Little Antente with Czechoslovakia and Roumania, in order to protect herself from neighbours like Italy which had territorial claims on her soil. After the assassination of King Alexander in 1934, the rapprochement between France and Italy forced Yugoslavia to seek a `neutrality` policy. But this policy did not prevent the invasion of the country by the German, Italian and Bulgarian armies in 1941. During foreign occupation in the Second World War, two majör resistance movements developed in Yugoslavia. While the Chetniks, under the leadership of Draza Mihajlovic, had the support of the Royal Yugoslav Government in exile in London and for a considerable time that of the Allied Powers, the Partisan movement was organised by the YC'P with the hope of receiving military aid from Soviet Union. in the first years of the war, the Soviet Union officially recognised the Chetniks as the main resistance movement and criticized the Partisans for being openly communist, urged YCP to collaborate with the Chetniks and deplored the formation of the Proletarian Brigades by the YCP. in the course of the resistance struggle when the Partisans gained strength and popularity and when the close relations of the Chetniks with the occupying German army became very much obvious, the Allies shifted their support from Mihajlovic to Tito. The Soviet Union's efforts to restrict the actions of the YCP, belated Soviet military assistanceS U M M A R Y The Kingdom of Yugoslavla was founded at the end of the First World War, on December l, 1918. Serbia was the dominant power in the Kingdom comprising ethnically different regions like Serbia, Crotia, Slovenia, Bosnia-Hercegovina and Montenegro. Serbians were repressing the other national groups in the name of the unity of the Kingdom of South Slavs. The Kingdom was an undeveloped and a semi-colonial country with an economy largely dependant on agricultural production. The majority of the peasantry, which constituted the main social segraent of the Yugoslav society, was in great poverty. Further, unegual economic development among the different regions of the country deteriorated the relations among the Yugoslav peoples. The slow pace of industrialisation yielded to a weak working class which was an important social base for the communist movement. Nevertheless, the Yugoslav Cummunist Party gained a limited but firm ground ali över Yugoslavia. The national tensions, political parties with short-sighted policies, failure of the administration in creating a relatively democratic monarchy and the great destitution fell upon the vast majority of the Yugoslavs contributed to the slow but determined progress of the YCP. in the second half of the 1930s, J.B. Tito gained distinction in the ranks of the Party and by putting an end to fractional370 disputes and uniting the Party, formally assumed charge of the Party in January 1939. Encouraged by France, Yugoslavia founded in 1921 the Little Antente with Czechoslovakia and Roumania, in order to protect herself from neighbours like Italy which had territorial claims on her soil. After the assassination of King Alexander in 1934, the rapprochement between France and Italy forced Yugoslavia to seek a `neutrality` policy. But this policy did not prevent the invasion of the country by the German, Italian and Bulgarian armies in 1941. During foreign occupation in the Second World War, two majör resistance movements developed in Yugoslavia. While the Chetniks, under the leadership of Draza Mihajlovic, had the support of the Royal Yugoslav Government in exile in London and for a considerable time that of the Allied Powers, the Partisan movement was organised by the YC'P with the hope of receiving military aid from Soviet Union. in the first years of the war, the Soviet Union officially recognised the Chetniks as the main resistance movement and criticized the Partisans for being openly communist, urged YCP to collaborate with the Chetniks and deplored the formation of the Proletarian Brigades by the YCP. in the course of the resistance struggle when the Partisans gained strength and popularity and when the close relations of the Chetniks with the occupying German army became very much obvious, the Allies shifted their support from Mihajlovic to Tito. The Soviet Union's efforts to restrict the actions of the YCP, belated Soviet military assistanceS U M M A R Y The Kingdom of Yugoslavla was founded at the end of the First World War, on December l, 1918. Serbia was the dominant power in the Kingdom comprising ethnically different regions like Serbia, Crotia, Slovenia, Bosnia-Hercegovina and Montenegro. Serbians were repressing the other national groups in the name of the unity of the Kingdom of South Slavs. The Kingdom was an undeveloped and a semi-colonial country with an economy largely dependant on agricultural production. The majority of the peasantry, which constituted the main social segraent of the Yugoslav society, was in great poverty. Further, unegual economic development among the different regions of the country deteriorated the relations among the Yugoslav peoples. The slow pace of industrialisation yielded to a weak working class which was an important social base for the communist movement. Nevertheless, the Yugoslav Cummunist Party gained a limited but firm ground ali över Yugoslavia. The national tensions, political parties with short-sighted policies, failure of the administration in creating a relatively democratic monarchy and the great destitution fell upon the vast majority of the Yugoslavs contributed to the slow but determined progress of the YCP. in the second half of the 1930s, J.B. Tito gained distinction in the ranks of the Party and by putting an end to fractional370 disputes and uniting the Party, formally assumed charge of the Party in January 1939. Encouraged by France, Yugoslavia founded in 1921 the Little Antente with Czechoslovakia and Roumania, in order to protect herself from neighbours like Italy which had territorial claims on her soil. After the assassination of King Alexander in 1934, the rapprochement between France and Italy forced Yugoslavia to seek a `neutrality` policy. But this policy did not prevent the invasion of the country by the German, Italian and Bulgarian armies in 1941. During foreign occupation in the Second World War, two majör resistance movements developed in Yugoslavia. While the Chetniks, under the leadership of Draza Mihajlovic, had the support of the Royal Yugoslav Government in exile in London and for a considerable time that of the Allied Powers, the Partisan movement was organised by the YC'P with the hope of receiving military aid from Soviet Union. in the first years of the war, the Soviet Union officially recognised the Chetniks as the main resistance movement and criticized the Partisans for being openly communist, urged YCP to collaborate with the Chetniks and deplored the formation of the Proletarian Brigades by the YCP. in the course of the resistance struggle when the Partisans gained strength and popularity and when the close relations of the Chetniks with the occupying German army became very much obvious, the Allies shifted their support from Mihajlovic to Tito. The Soviet Union's efforts to restrict the actions of the YCP, belated Soviet military assistance377 founders of the movement, especially Yugoslavia and India, were worried because of the radical wordings of the resolutions which they thought undermined the bargaining power of the non-aligned movement at the international fora. Leaders of these countries also urged that summits should focus on global issues and problems faced by the Third World countries and that the controversial and bilateral matters should not be included in the agenda. At the Fifth Summit, mostly as a result of the efforts by the Yugoslav delegation the non-aligned countries decided to call for a U.N. General Assembly Special Session on Disarmament. At the Colombo Summit the membership and functions of the Coordination Bureau was also increased. At this summit Tito played a unifying role as the only living founder of the movement. At the Sixth Non-Aligned Countries Summit, held in Havana, (September 3-9, 1979), Cuba tried hard to secure the endorsement of Soviet Union's natural ally status by using the advantage of being the host country to the meeting. Tito confronted the manoeuvres of Cuba's leader F. Castro and other radical leaders who were trying to align the move ment with the Socialist Bloc. At the Havana Summit non- alignment movement came to the edge of division. At the end of intense negotiations, Cuba and the radical wing of the movement withdrew from their position of persistence on the 'natural ally' thesis. However, according to the established practice the presidency of the movement was handed over to Cuba for the next three years.378 The Cyprus Question was first brought into the agenda of the non-aligned movement at its Cairo Summit by Archbishop Makarioş, the leader of the Greek -Cypriot administration. In the resolutions of the non-aligned summits, the issue was dealt with bias by favouring the arguments of Greek-Cypriots, though some rights of the Turkish-Cypriots were also mentioned. Yugoslavia backed this one-sided approach to the matter. According to the official interpretation of the country's foreign policy, Yugoslav non-alignment was the reflection of its internal system, s elf -management. As a social and political system, self-management was developed by Yugoslav leadership after the' country's dismissal from the Socialist Bloc. The main criticism against Yugoslav self- management was that it could not prevent the emergence of a new ruling class and it was unable to cope with the ethnic tensions among different nationalities of Yugoslavia. In 1991, Socialist Federal Republic of Yugoslavia collapsed after a bloody civil war. y 378