A stochastic programming approach to surgery scheduling under parallel processing principle

Parallel processing is a principle which enables simultaneous implementation of anesthesia induction and operating room (OR) turnover with the aim of improving OR utilization. In this article, we study the problem of scheduling surgeries for multiple ORs and induction rooms (IR) that function based on the parallel processing principle under uncertainty. We propose a two-stage stochastic mixed-integer programming model considering the uncertainty in induction, surgery and turnover durations. We sequence patients and set appointment times for surgeries in the first stage and assign patients to IRs at the second stage of the model. We show that an optimal myopic policy can be used for IR assignment decisions due to the special structure of the model. We minimize the expected total cost of patient waiting time, OR idle time and IR idle time in the objective function. We enhance the model formulation using bounds on variables and symmetry-breaking constraints. We implement a novel progressive hedging algorithm by proposing a penalty update method and a variable fixing mechanism. Based on real data of a large academic hospital, we compare our solution approach with several scheduling heuristics from the literature. We assess the additional benefits and costs associated with the implementation of parallel processing using near-optimal schedules. We examine how the benefits are inflated by increasing the number of IRs. Finally, we estimate the value of stochastic solution to underline the importance of considering uncertainty in durations.</p

Stochastic scheduling of chemotherapy appointments considering patient acuity levels

The uncertainty in infusion durations and non-homogeneous care level needs of patients are the critical factors that lead to difficulties in chemotherapy scheduling. We study the problem of scheduling patient appointments and assigning patients to nurses under uncertainty in infusion durations for a given day. We consider instantaneous nurse workload, represented in terms of total patient acuity levels, and chair availability while scheduling patients. We formulate a two-stage stochastic mixed-integer programming model with the objective of minimizing expected weighted sum of excess patient acuity, waiting time and nurse overtime. We propose a scenario bundling-based decomposition algorithm to find near-optimal schedules. We use data of a major university hospital to generate managerial insights related to the impact of acuity consideration, and number of nurses and chairs on the performance measures. We compare the schedules obtained by the algorithm with the baseline schedules and those found by applying several relevant scheduling heuristics. Finally, we assess the value of stochastic solution

Stochastic scheduling of chemotherapy appointments considering patient acuity levels

The uncertainty in infusion durations and non-homogeneous care level needs of patients are the critical factors that lead to difficulties in chemotherapy scheduling. We study the problem of scheduling patient appointments and assigning patients to nurses under uncertainty in infusion durations for a given day. We consider instantaneous nurse workload, represented in terms of total patient acuity levels, and chair availability while scheduling patients. We formulate a two-stage stochastic mixed-integer programming model with the objective of minimizing expected weighted sum of excess patient acuity, waiting time and nurse overtime. We propose a scenario bundling-based decomposition algorithm to find near-optimal schedules. We use data of a major university hospital to generate managerial insights related to the impact of acuity consideration, and number of nurses and chairs on the performance measures. We compare the schedules obtained by the algorithm with the baseline schedules and those found by applying several relevant scheduling heuristics. Finally, we assess the value of stochastic solution

Endüstriyel tav fırınlarında ısı denkliği hesaplamaları ve enerji verimliliğinin belirlenmesi

Enerji verimliliğinde artıs sağlanması endüstriyel sistemlerdeki ısıl kayıpların yerlerinin ve miktarlarının belirlenmesi ile mümkün olmaktadır. Fırınlar, özelikle yüksek sıcaklıklarda çalısan tavlama fırınları, endüstriyel isletmelerde gerek yakıt tüketimi açısından gerekse çevreye verdiği atık gazların olusturduğu kirlilik açısından mümkün olduğunca verimli çalıstırılması gereken sistemlerdir. Bu çalısmada, endüstriyel tav fırınlarında enerji kaybının görüldüğü baslıca kısımlar incelenmis; enerji verimlilik analizi yapılmıs, termal verim bulunarak fırının enerji akısını gösteren Sankey diyagramı olusturulmustur. Baca gazı bilesenleri yüzdesel olarak belirlenmis, bu bilgilerden hareketle baca gazından olan kayıp tespit edilmistir. Fırının konveksiyon ve radyasyon yüzeyleri ile yüzey sıcaklıkları tespit edilerek yüzey kayıpları belirlenmistir. Tavlanan malzemeye aktarılan enerji bulunmus; birim zamanda tüketilen yakıt ve de tavlanan ürün miktarı da belirlenerek buradan toplam yakıt tüketimi giren enerji olarak elde edilmistir. Giren enerji ile ürüne aktarılan enerji arasındaki farkın hangi tür kayıplar olduğu ve miktarları Sankey diyagramında gösterilmistir. Analiz sonunda fırındaki kayıpların azaltılmasına yönelik görüs ve önerilere yer verilmistir

İlköğretim Matematik Öğretmeni Adaylarına Yönelik Çok Kültürlü Sınıflarda Öğretim ve Kendi Öğretme Uygulamaları Üzerinde Düşünme Fırsatları Ölçeğinin Geçerlik ve Güvenirlik Çalışması

Bu araştırmanın amacı, uluslararası TEDS-M çalışması için geliştirilmiş Çok Kültürlü Sınıflarda Öğretim ve Kendi Öğretme Uygulamaları Üzerinde Düşünme Fırsatları Ölçeği’nin (Tatto vd., 2008) Türkçe formunun geçerlik ve güvenirliğini incelemektir. Araştırma Türkiye’nin yedi farklı bölgesinden rastgele seçilen birer üniversiteden toplam 583 ilköğretim matematik öğretmeni adayı üzerinde yürütülmüştür. Açımlayıcı faktör analizi sonucunda toplam açıklanan varyansın %72 olduğu ve maddelerin iki faktör altında toplandığı görülmüştür. Doğrulayıcı faktör analizinde iki boyutlu modelin iyi uyum verdiği görülmüştür (x2=192.37, sd=34, RMSEA=0.07, CFI=0.97, GFI=0.93, AGFI=0.88). Türkçe formda bulunan maddeler ile toplam arasındaki korelasyon katsayılarının 0.77 ile 0.91 arasında değiştiği bulunmuştur. Ölçeğin iç tutarlılık güvenirlik katsayıları çok kültürlü sınıflarda öğretim alt boyutu için 0.90 ve kendi öğretme uygulamaları üzerinde düşünme için 0.92 olarak bulunmuştur. Bu sonuçlar ölçeğin Türkçe formunun geçerli ve güvenilir bir ölçme aracı olduğunu göstermektedir

Morus alba’ nın meyve ve yaprak ekstrelerinin antioksidan kapasitelerinin belirlenmesi

Bu çalışmada Elazığ’dan toplanan Morus alba’ nın antioksidan ve antiradikal kapasitesi incelendi. Bitkinin yaprakları ve meyveleri gölgede kurutularak ayrı ayrı su ve etanol ekstreleri hazırlandı. Ekstreler soksilet cihazı ile yapıldı. Bu ekstrelerin antioksidan ve antiradikal testleri, toplam antioksidan kapasite, indirgeme gücü kapasitesi, metal şelatlama aktivitesi, DPPH• serbest radikali giderme aktivitesi, ABTS•+ radikali giderme aktivitesi, süperoksit anyon radikalleri giderme aktivitesi, H2O2 giderme aktivitesi ve FRAP testi gibi farklı antioksidan metotlar ve ek olarak toplam fenolik bileşik miktarı tayini kullanılarak farklı konsantrasyonlarda ayrı ayrı belirlendi. Elde edilen sonuçlara bakıldığında dutun yapraklarının ve meyvelerinin iyi bir serbest radikal gidericisi olduğu ve doğal bir antioksidan olarak kullanılabileceği bulundu.In this study Morus alba investigated the antioxidant and antiradical capacity that it was collected from Elazıg. Leaves and fruits of plants dried in shade, water and ethanol extracts were prepared separately . The extracts were made with Soxhlet apparatus. These extracts, antioxidant and antiradical tests, different antioxidant methods such as total antioxidant capacity, reducing power capacity, metal chelating activity, DPPH• free radical scavenging activity, ABTS•+ radical scavenging activity, superoxide anion radicals scavenging activity, H2O2scavenging activity and FRAP test and in addition to by using the amount of the total phenolic compounds determined separately at different concentrations. Looking at the results obtained, leaves and the fruits of mulberry found as a good free radical scavenging and was used as a natural antioxidant

Effects of Rubus discolor flower extract on the fatty acid composition in hydrogen peroxide administered Wistar rats

The aim of this research is to examine possible protective effects of Rubus discolor (RD) flower extracts on the fatty acid contents of some tissues, which hydrogen peroxide (HP) administered Wistar rats. In present study, Wistar rats were randomly divided into four groups: 1. Control (C), 2. Hydrogen Peroxide (HP), 3. Rubus discolor (RD), 4. Rubus discolor + Hydrogen Peroxide (RD+HP). In tissues, fatty acid content analyses were performed by gas chromatography. According to our results, while fatty acid levels were barely affected in the heart, muscle, brain and spleen tissues of HP group, but these levels were affected in the serum, liver, kidney and lung tissues of the same group when compared to the control group. The fatty acid contents were changed in all tissues of RD and RD+HP groups when compared to control group. Our results confirm that RD and HP treatment have affected the amount of important fatty acids, which substrates in fatty acids metabolism of Wistar rats. In also, this study is first report about the effects of R. discolor flower extract on the fatty acid composition.Bu çalışmanın amacı hidrojen peroksit (HP) uygulanmış Wistar sıçanların bazı dokularının yağ asidi içeriği üzerinde Rubus discolor (RD) çiçek ekstresinin olası koruyucu etkilerini incelemektir. Sunulan çalışmada, Wistar sıçanlar rastgele 4 ayrı gruba ayrıldı: 1. Kontrol (C), 2. Hidrojen Peroksit (HP), 3. Rubus discolor (RD), 4. Rubus discolor + Hidrojen Peroksit (RD+HP). Dokulardaki yağ asidi içeriği gaz kromatografisi cihazıyla analiz edildi. Sonuçlarımıza göre, kontrol grubuyla karşılaştırıldığı zaman, HP grubunun kalp, kas, beyin ve dalak dokusunda yağ asidi seviyeleri hemen hemen hiç etkilenmezken, aynı grubun serum, karaciğer, böbrek ve akciğer dokularında yağ asitleri seviyeleri etkilenmiştir. RD ve RD+HP gruplarının bütün dokularında yağ asidi içeriği kontrol grubuna göre değişmiştir. Sonuçlarımız göstermiştir ki RD ve HP uygulaması, Wistar sıçanların yağ asidi metabolizmasında substrat olan bazı önemli yağ asitlerinin miktarını etkilemiştir. Ayrıca bu çalışma R. discolor çiçek ekstresinin yağ asidi içeriği üzerindeki etkileri hakkında ilk rapordur

Children's Foreign Language Anxiety Scale: Preliminary Tests of Reliability and Validity

Foreign language anxiety (FLA), which constitutes a serious problem in the foreign language learning process, has been mainly seen as a research issue regarding adult language learners, while it has been overlooked in children. This is because there is a lack of appropriate tools to measure FLA among children, whereas there are many studies on the scales that aim to measure anxiety levels among adult learners. Thus, the current study aims to conduct the preliminary tests of reliability and validity of the Children's Foreign Language Anxiety Scale (CFLAS) and to report on the pilot examination of reliability, validity and factor structure of the CFLAS. The findings of the pilot study show that CFLAS is a reliable and valid tool to measure FLA levels among children who learn English as a foreign language (EFL) within the age range of 7-12 in a Turkish EFL context

Retrospective analysis of Turkish AML registry database, on behalf of AML working group of Turkish society of hematology

Abstract Introduction: To investigate the demographics and treatment details of the acute myeloid leukemia (AML) patients who were diagnosed and followed up in Turkey. Methods: Patients who were recorded on the database of Turkish AML Registry project were included in this study retro- spectively if they were diagnosed before 1st of Jan 2022. Demographics, patient, and disease related parameters both at the time of diagnosis and at the follow up and treatment outcomes were presented

BRAF V600E mutation in papillary thyroid cancer is correlated with adverse clinicopathological features but not with iodine exposure

Introduction: BRAFV600E activating mutation is the most frequent genetic abnormality in the pathogenesis of papillary thyroid carcinoma. We aimed to evaluate the association between BRAFV600E mutation and well-established prognostic clinicopathological characteristics as well as iodine exposure. Material and methods: From 2000 to 2012, the data of PTC patients admitted to Dr. Lutfi Kirdar Kartal Education and Research Hospital in Turkey were reviewed retrospectively. Clinicopathological parameters were collected. BRAFV600E mutation was analysed by DNA sequencing method in tumour specimens. We hypothesised that BRAFV600E mutation prevalence is positively correlated with prolonged iodine exposure and expected to be higher in the second half of the recruitment period due to the increment in time spent from the iodisation process of the table salt in our country. Thus, iodine exposure was categorised as short-term (2000–2006) and long-term (2006–2012). Results: A total of 197 patients were accrued. The study population predominantly consisted of conventional variant. A statistically significant relationship was observed between BRAFV600E mutation presence and age (p = 0.03), conventional variant PTC (p = 0.00002), T4 stage (p = 0.002), vascular invasion (p = 0.036), thyroid capsule invasion (p &lt; 0.00001), extrathyroidal tissue invasion (p &lt; 0.00001), and lymph node metastasis (p &lt; 0.00001). When categorised as long-term and short-term, iodine exposure was not statistically significantly related with BRAFV600E mutation; however, there were far more PTC cases in the long-term group (86.3% vs. 13.7%). Conclusion: We revealed that BRAFV600E mutation is associated with adverse clinicopathological parameters. There appeared to be no relation between long-term iodine exposure and BRAFV600E.