Lojistik regresyon modeller ve bir uygulama

Bu tezin, veri tabanı üzerinden yayınlanma izni bulunmamaktadır. Yayınlanma izni olmayan tezlerin basılı kopyalarına Üniversite kütüphaneniz aracılığıyla (TÜBESS üzerinden) erişebilirsiniz.VII ABSTRACT LOGISTIC REGRESSION MODELS AND AN APPLICATION SAPMAZ (YBLMAZ), Kadriye MSc in Statistics Supervisor: Prof.Dr. Onur BAŞKAN February 1999, 78 pages In this study, linear probability model, logistic regression model and probit model were scrutinized from the models which can be used when the dependant variable Y is a binary variable under the statistical model concept. Depending on the data related to the patients in tiie Anesthesiology and Intensive Care Clinic of the Aegean University, the applicability of these models were discussed. For determining the factors effecting the death of the patients in this clinic, logistic regression model which was determined to be the most appropriate model among those three models was used. As a result of the analysis model; it was determined that the increase of APACHE II Score Degree and the presence of Hypocsic Period and Multiple Organ Dysfunction Complications effects the death of a patient. Furthermore, from the factors used for determining the score degree of APACHE II, the factors effecting the death of the patients were estimated by means of a model. From the factors examined; it was determined that low Mean Arterial Pressure (MAP) and Respiratory Rate and high Serum Creatinine effect the death of the patient. Keywords: Binary Dependent Variable, Linear Probability Model, Probit Model, Logistic Regression Model.V ÖZET LOJİSTİK REGRESYON MODELLER VE BİR UYGULAMA SAPMAZ (YILMAZ), Kadriye Yüksek Lisans Tezi, İstatistik Bölümü Tez Yürütücüsü: Prof.Dr. Onur BAŞKAN Şubat 1999, 78 Sayfa Bu çalışmada, istatistiksel model kavramı altında Y bağımlı değişkeninin iki sınıflı bir değişken olması durumunda kullanılabilecek modellerden; doğrusal olasılık modeli, lojistik regresyon model ve probit model ele alınmıştır. Bu modellerin E.Ü. Anesteziyoloji ve Reanimasyon Kliniğindeki hastalara ilişkin verilere bağlı olarak uygulanabilirlikleri tartışılmıştır. Klinikteki hastaların ölümüne etki eden faktörlerin belirlenmesinde, bu üç modelden en uygun model olarak belirlenen lojistik regresyon model kullanılmıştır. Yapılan analizler sonucunda; APACHE II Skor Derecesindeki artışın, Hastada Hipoksik Periyod ve Multiple Organ Yetmezliği Komplikasyonlannm bulunmasının hastanın ölümüne etki ettiği belirlenmiştir. Ayrıca APACHE Il'nin skor derecesini belirlemede kullanılan faktörlerden hastanın ölümüne etki eden faktörler bir model yardımı ile tahmin edilmiştir. İncelenen bu faktörlerden; Ortalama Arter Basıncının (MAP) ve Solunum Hızının düşük olmasının ve Serum Kreatininin yüksek olmasının hastanın ölümüne etki ettiği belirlenmiştir

Tüketicilerin Market Markalı ve Üretici Markalı Gıda Ürünü Tercihlerinin Analizi: İzmir İli Örneği

In this study, the prevailing product features such as price, quality, food safety and brand awareness in store branded and manufacturer branded food product preference of and purchasing behaviours against store branded food products of consumers living in Central Towns of Izmir Province are examined. The main material of this study is original data that obtained from the face to face interviews with 650 consumers. Analytic hierarchy process and descriptive statistics were used analysis of the data. It is seen that the consumers participated in queries have rather preferred manufacturer branded food products (0.68) than store branded food products (0.32) and it is determined that the most efficient product quality in the preference of the consumers is the food safety. Along with such results, it is determined that the 65% of the consumers have consumed store branded food products and that the most preferred store branded food products are rice, legumes, milk, yoghurt and pasta respectively. It is concluded that it will be important that retailers go into differentiation in the weights of their store branded products and attract the attention of the consumers to the information on the producing company in increasing the demand for the store branded food products.Bu araştırmada, İzmir İli merkez ilçelerinde yaşayan tüketicilerin market markalı ve üretici markalı gıda ürünü tercihlerinde fiyat, kalite, gıda güvenliği, marka tanınırlığı ürün özelliklerinden hangilerinin öne çıktığı belirlenmeye çalışılmış ve market markalı gıda ürünlerine yönelik satın alma davranışları incelenmiştir. Araştırmanın ana materyalini 650 tüketici ile yapılan anketlerden elde edilen veriler oluşturmuştur. Verilerin analizinde analitik hiyerarşi süreci ve tanımlayıcı istatistikler kullanılmıştır. Ankete katılan tüketicilerin üretici markalı gıda ürünlerini (0.68) market markalı gıda ürünlerine (0.32) göre daha çok tercih ettiği görülmüş ve tüketicilerin bu tercihlerinde en etkili olan ürün özelliğinin gıda güvenliği olduğu tespit edilmiştir. Tüketicilerin % 65’inin market markalı gıda ürünü tükettiği ve en çok tercih edilen market markalı gıda ürünlerinin sırası ile pirinç, bakliyat, süt, yoğurt ve makarna olduğu belirlenmiştir. Market markalı gıda ürünlerine olan talebin arttırılmasında, perakendecilerin kendi markalı ürünlerinin gramajlarında farklılaşmaya gitmelerinin ve tüketicilerin ilgisini üretici firma bilgisine çekmelerinin önemli olacağı sonucuna varılmıştır

Role of the second trimester maternal serum AFP levels in diagnosing gestational diabetes mellitus, low birth weight and preterm labor

Amaç: Gebeliğin ikinci trimester inde ölçülen maternal serum alfa-fetoprotein (AFP) düzeylerinin gebeliğin ilerleyen döne¬minde oluşabilecek gestasyonel diabetes mellitus, düşük doğum ağırlıklı bebek ve preterm doğum eyleminin tahmin edilebil-mesindeki rolünü araştırmak. Materyal ve Metot: Down sendromu tarama programı için başvuran 412 hastanın, maternal serum AFP düzeyleri geriye dö¬nük olarak tarandı. Maternal midtrimester serum AFP değerleri, fetusun biparietal çap ölçümü temel alınarak, gebeliğin 15-20. haftalarında yapıldı. AFP değerleri "Multiple of Median" (MoM) olarak ifade edildi. 50 g glukoz yükleme testi pozitif çıkan ve 100 g OGTT sonucu negatif çıkan olgular glukoz intolerant (n=45), 50 g glukoz ve 100 g OGTT sonuçları pozitif çıkan hastalar gestasyonel diabetes mellitus (n=19) olarak kabul edildi. 50 g yükleme sonucu negatif çıkan (n=348) olgular bu grup için kontrol grubu olarak kabul edildi. Otuz yedinci gebelik haftasından önce gerçekleşen doğumlar, preterm olarak adlandırıldı. Doğum kilosu 4000 g olan bebekler ise makrozomik olarak tanımlandı. Sonuçlar: Preterm doğum yapan 27 gebenin maternal serum AFP düzeyi, term dönemde doğum yapan 385 gebeye [1.21 ±1.27 MoM vs 0.88±0.46.MoM] göre daha yüksekti (P=0.000). Düşük doğum ağırlıklı (0.05). Tartışma: Gebeliğin ikinci trimester Down sendromu tarama testi içinde yer alan ve yüksek maternal serum AFP ile seyre¬den gebeliklerin, perinatal mortalite için önemli yer tutan düşük doğum ağırlıklı bebek ve preterm doğumları tahmin edebil¬mede önemli bir belirteç olduğunu düşünüyoruz.Objective: To investigate the role of maternal serum alpha-fetoprotein (AFP) levels measured in the second trimester of pregnancy for Down Syndrome screening in predicting the outcome of pregnancy associated with gestational diabetes melli¬tus, low birth weight and preterm labor. Materials and Methods: This study was conducted retrospectively in 412 pregnant women whom applied for Down Syndro¬me Screening Test. Maternal midtrimester AFP levels were obtained between 15* to 20th weeks of gestation on the basis of fetal biparietal measurement. AFP levels were defined as MoM. Pregnant women were considered negative (control) when their blood glucose level was 140 mg/dL and a positive 100 g oral glucose tolerance test (OGTT) is defined gestational diabetes mellitus (n=19). Those with one hour postprandial plasma glucose concentration >140 mg/dL and a negative 100 g oral glucose tolerance test (OGTT) is defined glucose intolerant (n=45). Preterm labor is described as labor that occured prior to 37th weeks of gestation. Babies who¬se weight was lower than 2500 g is defined low birth weight, and birth weight higher than 4000 g is defined macrosomic. Results: Maternal serum AFP levels of 27 preterm labored women were high as compared to 385 women labored in term [1.21±1.27 MoM vs 0.88±0.46 MoM] (P=0.000). Maternal serum AFP levels of babies with low birth weight (25OO g), [1.34±l-38 MoM vs 0.88±0.45 MoM] and this difference was significant (P=0.000). The level of AFP in pregnant women with gestational diabetes mellitus and glucose intolerance without complication were 0.92, 0.76 and 0.81 MoM, respectively and this difference was not significant (P>0.05). Conclusion: We contemplate pregnancies with a high maternal serum AFP, which is measured during the second trimester for Down syndrome screening test, is a crucial marker in predicting the pregnancy outcome in respect to birth weight and preterm labor

In Vitro Shear Bond Strength Between Fluorinated Zirconia Ceramic And Resin Cements

PURPOSE The purpose of this study was to evaluate the efficiency of a gas-phase fluorination method under different fluorination periods through using two resin cements. MATERIALS AND METHODS 84 zirconia specimens in dimensions of 5 mm × 5 mm × 2 mm were prepared and surface treated with 50 µm aluminum oxide particles or gas phase fluorination for 2 min, 5 min, or 10 min. One specimen in each group was surface analyzed under scanning electron microscope. The remaining specimens were bonded to composite cylinders in dimensions of 2 mm diameter and 3 mm high with Panavia SA Plus or Variolink N. Then, the specimens were stored in 37℃ distilled water for 24 hours and shear bond strength test was applied at a speed of 1 mm/min. RESULTS The highest shear bond strength values were observed in the samples fluorinated for 5 minutes and cemented with Panavia SA Plus. Variolink N did not elicit any statistical differences between surface treatments. Panavia SA Plus resin cement and Variolink N resin cements featured statistically significant difference in shear bond strength values only in the case of 5 minutes of fluorination treatment. CONCLUSION According to the results of this study, application of 5 minutes of fluorination with 10-methacryloyloxydecyl dihydrogen phosphate monomer (MDP) containing Panavia SA Plus resin cement increased the resin bond strength of zirconia. Fluorination of the zirconia surface using conventional resin cement, Variolink N, did not lead to an increase in bond strength.PubMedWoSScopu

Detection of Intestinal Parasites with Conventional and Molecular Methods in Follow-up HIV/AIDS Cases

In people living with human immunodeficiency virus (HIV), several complaints related to the gastrointestinal system, mainly diarrhea can be determined. In our study, we aimed to detect the existence of intestinal parasites with conventional methods based on microscopy and with molecular methods based on multiplex-PCR among 90 anti-retroviral treatment (ART) naive or ART adherent HIV/AIDS cases. The existence of Giardia spp., Blastocystis spp., Entamoeba histolytica, Dientamoeba spp. and Cryptosporidium spp. were searched in stool samples and the relation with the existence of these parasites and demographic/clinical data of the cases were determined. The demographic and clinical data of the participants included in the study were as follows; the average age was 34.02 +/- 9.7 years, average time of diagnosis was 2.4 +/- 1.7 years. Gender distribution was as follows; 85.6% male and 14.4% female. HIV transmission was related with heterosexual intercourse in 60%, homosexual intercourse in 33.3%, blood/blood products contact in 1.1% and with unknown routes in 5.6% of the cases. Fifty percent of the patients were in pre-ART and 50% was in on-ART state. The average CD4+ T lymphocyte count was detected as 400 cells/mm(3) and the median of viral load was 114.527 copies/ml. An overall prevalence of at least one intestinal parasitic infection was recorded as 36.7% and the prevalence of this infection due to Blastocystis spp. was 22.2%, followed by Dientamoeba spp. (13.3%), E. histo lytica (4.4%), Cryptosporidium spp. (3.3%), Giardia spp. (2.2%) and multiple parasitic infections (7.7%). The type of sexual behaviours related with the detection of intestinal parasites were statistically significant especially in homosexual intercourse (p< 0.001). The increase in CD4+ T lymphocyte counts were reversely associated (p= 0.062) and the increase in the levels of viral load were positively associated (p< 0.001) with detection rate of intestinal parasite. The detection of parasites by molecular methods was statistically significant in pre-ART participants (p= 0.002) and participants with diarrhea (p= 0.019). In the present study, the increase in the frequency of intestinal parasitic infections has shown that essential interventions are required. In all HIV/AIDS cases, routine parasitic screening should be performed by more sensitive methods to manage early and specific treatment