Fat fraction mapping using bSSFP Signal Profile Asymmetries for Robust multi-Compartment Quantification (SPARCQ)

Purpose: To develop a novel quantitative method for detection of different tissue compartments based on bSSFP signal profile asymmetries (SPARCQ) and to provide a validation and proof-of-concept for voxel-wise water-fat separation and fat fraction mapping. Methods: The SPARCQ framework uses phase-cycled bSSFP acquisitions to obtain bSSFP signal profiles. For each voxel, the profile is decomposed into a weighted sum of simulated profiles with specific off-resonance and relaxation time ratios. From the obtained set of weights, voxel-wise estimations of the fractions of the different components and their equilibrium magnetization are extracted. For the entire image volume, component-specific quantitative maps as well as banding-artifact-free images are generated. A SPARCQ proof-of-concept was provided for water-fat separation and fat fraction mapping. Noise robustness was assessed using simulations. A dedicated water-fat phantom was used to validate fat fractions estimated with SPARCQ against gold-standard 1H MRS. Quantitative maps were obtained in knees of six healthy volunteers, and SPARCQ repeatability was evaluated in scan rescan experiments. Results: Simulations showed that fat fraction estimations are accurate and robust for signal-to-noise ratios above 20. Phantom experiments showed good agreement between SPARCQ and gold-standard (GS) fat fractions (fF(SPARCQ) = 1.02*fF(GS) + 0.00235). In volunteers, quantitative maps and banding-artifact-free water-fat-separated images obtained with SPARCQ demonstrated the expected contrast between fatty and non-fatty tissues. The coefficient of repeatability of SPARCQ fat fraction was 0.0512. Conclusion: The SPARCQ framework was proposed as a novel quantitative mapping technique for detecting different tissue compartments, and its potential was demonstrated for quantitative water-fat separation.Comment: 20 pages, 7 figures, submitted to Magnetic Resonance in Medicin

AN ANALYSIS OF BUSINESS CYCLES UNDER REGIME SHIFTS: THE TURKISH ECONOMY AND INDUSTRIAL SECTOR

This paper analyzes the time series behavior of the annual growth rate of Turkey's GDP and growth rate of its industrial sector GDP's. Drawing on the work of Hamilton (1989), we examine the two series for evidence of periodic, discrete shifts in the mean using a two-state Markov regime switching model. The results provide strong evidence that shifts in the mean of the growth process both general and sectoral is a prominent feature of the data. According to probability results, there is one switch between the regimes in general growth process and there are five switches in industrial sector growth process

Prevalence and distribution of odontogenic and nonodontogenic cysts in a Turkish population

Objective: To determine the relative frequency and distribution of odontogenic and nonodontogenic cysts in a large Turkish population. Study Design A retrospective survey of jaw cysts was undertaken at the Oral Diagnosis and Radiology and Oral and Maxillofacial Surgery Department, Ondokuz Mayis University Dental School, Samsun, Turkey. Data were retrieved from clinical files, imaging, and histopathology reports from 2000 to 2008: a total of 12,350 patients were included. In each case, we analyzed age, gender, type and number of cysts, and cyst location. Imaging patterns and pathologies associated with cystic lesions were also determined. Results: The prevalence of odontogenic and nonodontogenic cysts was 3.51%; males were affected more frequently than females. There were 452 odontogenic cysts (98.5%) and seven nonodontogenic cysts (1.5%). The most frequent odontogenic cyst was radicular (54.7%), followed by dentigerous (26.6%), residual (13.7%), odontogenic keratocyst (3.3%), and lateral periodontal cyst (0.2%). Nasopalatine duct cyst (1.5%) was the only nonodontogenic cyst. By age, cysts peaked in the third decade (24.2%). Concerning location, no statistically significant difference was found between the maxilla and mandible (p>0.05). The most frequent radiological feature of these lesions was unilocular cyst (93.7%). Pathologies associated with cystic lesions occurred in 14.7%. Conclusion: The prevalence of both odontogenic and nonodontogenic cysts were lower than that reported in many other studies. In our study population, cysts were mainly inflammatory in origin. © Medicina Oral S. L

Sources of Growth in the Turkish Economy: A Non-parametric Approach

Bir ekonomide büyümenin kaynaklarının geleneksel büyüme muhasebesi çerçevesinde tahmini faktör piyasalarının rekabetçi oldukları ve üretim fonksiyonunun belirli bir kalıba uyduğu şeklindeki varsayımların sağlanmasını gerektirmektedir. Bu çalışmada Iwata vd. (2003) çalışmasından hareketle Türkiye ekonomisinde büyümenin kaynakları ve toplam faktör verimliliği (TFV) 1968-2006 dönemi için söz konusu varsayımların sağlanmasını gerektirmeyen parametrik olmayan regresyon analizi ile tahmin edilmiştir. Çıktının sermaye ve işgücü girdisine göre esneklik katsayılarının parametrik olmayan regresyon tahminleri Türkiye ekonomisinde ölçeğe göre azalan getiri olduğunu göstermektedir. Tahmin sonuçlarına göre 1980 öncesi dönemde büyümenin kaynağı sermaye birikimi iken, 1980 sonrası dönemde 1991-95 yılları dışında TFV büyümesidir. İşgücünün büyümeye en önemli katkısını 1991-95 döneminde yaptığı gözlenmiştir.Estimating the sources of economic growth within the framework of the conventional growth accounting approach is based on two assumptions namely the factor markets are competitive and the underlying aggregate production function has a specific form. In this study, following Iwata et al (2003), sources of economic growth and total factor productivity (TFP) growth in the Turkish economy for the period 1968-2006 were estimated with nonparametric regression approach which does not require imposing these restrictive assumptions. Nonparametric estimates of income share of capital and labor indicated there are diminishing returns to scale in the Turkish economy. According to results, capital formation is the main sources of growth before in the pre-1980 period, TFP is the sources of growth with the exception of 1991-95 period and post-1980 period seems to be the sources of growth. It is observed that labor's contribution to economic growth reached the highest level in the 1991-95

Conservation proposals for the 19 th century churches in Kayseri

The history of Christian population in Kayseri, dates back to the times when Christianity was still a secret religion. Armenians and Greeks continued their existence under the protection of the Ottoman Empire. Their influence and role (who were mostly occupied with trade and crafts), on the urban culture and the formation of urban fabric was remarkably high. Although Ottoman state offered freedom to the non-muslims in their beliefs, traditions and identities, heir daily life is controlled by certain rules. Their architectural activity was restricted; such that construction of new churches was not allowed, restorations were only possible by permission from the sultan, and domes and bell towers were prohibited. Westernisation movement and pressures of Europe and Russia resulted in the declarations of Tanzimat and Islahat, offering great changes in the lives of non-muslims. These developments gave non-muslims the statute of minority. This statute enabled them to express their economic and cultural accumulation, best probably by means of church building. Another development was the desolation of the Ottoman state system for a long time, which gives rise to the activities of missionaries. Thus, in addition to the Gregorian and Orthodox churches, Protestants and Catholics also started to have their churches. About the 130 churches at the end of 19th century can be considered as the reflections of these changes in Kayseri. However, the events which enabled the construction of the churches led to a chaos in time and ended up in deportation of Armenians, and the population exchange between Greeks in Anatolia and Muslims in Greece, which meant abandonment of churches. Some of them were demolished by vandalism, pillage or urbanisation. The surviving churches were gone under private ownership, and used in different functions harming their architectural identity, without regarding their documentary, artistic, historical and cultural heritage value. Another danger these churches face is dilapidation. All of the churches which still stand today exhibit damages due to above mentioned factors. These churches with the European and Istanbul influences they exhibit are the noticeable examples o westernisation in Kayseri, reflecting the socio-economic structure and the architectural character of their period. In addition to their documentary value, they also make great artistic contributions to the urban fabric. These values necessitate preserving these buildings which structured the thesis. The phases of the study can be summarised as; the survey of the churches in and around Kayseri, depiction of their physical characteristics and the analysis of the social and physical structure of the settlements they were in, defining their existing conditions, assessment and discussion of conservation problems and methods. The survey and the literary sources revealed that 39 churches are still standing and 56 are demolished. Existing churches were grouped into four categories according to their state of preservation; a) well preserved, b) badly preserved, c) preserved with major changes and d) partially existing. Badly preserved churches form the core of the thesis. Churches under this category were measured and drawn to 1/200 scale, examined in detail regarding their location, history, plan schema, construction techniques, decoration, and their damage levels. Churches in other categories were studied by presenting the existing drawings and photographs, in order to define their position in the church architecture of the Kayseri region. Beginning with the discussion of conservation problems the proposals are developed considering the headings like; legal and institutional dimensions, economic resources and the present facts of the persons who are concerned. The restoration and re-use proposals for each building are developed considering the least intervention in order to preserve the original architectural characteristics. The conditions and needs of the settlements are the other important factors. Yet, the current social structure of the environment is not suitable to reuse the churches. The proposals exceed the scale of the each settlement because other dimensions like the relationship between the settlements and the city centre and architectural, social and natural characteristics are also considered. Grouping these settlements with these considerations defines some excursion routes that would be effective in improving the cultural life of Kayseri. While the churches in these routes are planned to be kept alive by cultural functions, proposals are developed according to the particular needs of the settlements for the other churches departed from the excursion routes. Keywords: 19th century, church, Kayseri, conservation, new function, Tanzimat. Osmanlı İmparatorluğu’na bağlı gayrimüslimler için 19. yüzyıl, önemli değişimlerin yaşandığı bir dönemdir. Batılılaşma hareketleri ve diğer gelişmelerin devamında yayınlanan Tanzimat Fermanı ile tanınan haklar, bu yüzyılda ticari etkinliklerini artırarak ekonomik düzeylerini yükselten gayrimüslimlere çok sayıda yeni kilise yapabilecekleri bir ortam hazırlamıştır. Önemli oranda Ermeni ve Rum nüfusu barındıran Kayseri de bu gelişmelerden etkilenmiştir. Yapı ustaları ve mimarları ile tanınan kent bu dönemde, ayrıntılarda Batı etkilerinin izlenebildiği kiliselerle donatılmıştır. Mübadele ve tehcirle terk edilen, vandalizm, kötü kullanım ya da bakımsızlık gibi nedenlerle hasar gören bu kiliseler, dönemlerinin sosyal ve mimari yapısını yansıtan birer belgedir. Kent dokusuna yaptıkları estetik katkı ise korunmalarını gerekli kılan bir diğer nedendir. Çalışmanın, bu etkenlerle yönlenen amacı; daha önce envanteri yapılmamış söz konusu kiliselerin tespiti, fotoğraf ve rölövelerle belgelenmesi, bugünkü durum ve korunma problemlerinin belirlenmesi ve koruma önerileri geliştirilmesidir. Kiliseleri, bulundukları yerleşimlerle birlikte değerlendirmeyi amaçlayan öneriler; yasal ve örgütsel boyutları, kaynak sağlanması, girişimcilerin birikim ve deneyimleri vb. açılardan da ele alınmış, onarım ve yeniden işlevlendirme önerileri geliştirilirken ise yapıların özgün mimari karakterlerinin bozulmamasına özen gösterilmiştir. Yerleşimlerin birbirleri ve kent merkezi ile ilişkileri, mimari ve doğal dokularının sürekliliği göz önüne alınarak, kentin tanıtımı ve sosyal-kültürel hayatının canlandırılmasını hedefleyen rotalar belirlenmiştir. Bu rotalarda yer alan kiliselerin kültür, eğitim, toplantı vb. işlevlerle kullanılmaları önerilmiştir. Anahtar Kelimeler: 19.yüzyıl, kilise, Kayseri, koruma, yeni işlev, Tanzimat Fermanı

Does Export or Import More Effective on Turkish Growth Dynamics?

Bu çalışmada, ihracat ve ithalat yönlü büyüme hipotezleri çerçevesinde, 1989-2007 döneminde, Türkiye'nin GSYİH'sının büyüme dinamiğine ihracat ve ithalatın katkısı araştırılmıştır. Elde edilen bulgulara göre; daralma döneminden genişleme dönemine geçerken ihracat baskın rol oynamaktadır, ekonomi genişleme döneminde iken bu sürecin sürdürülmesinde ihracat ve ithalat birlikte katkı sağlamaktadır ve ihracatın ve ithalatın söz konusu katkıları azalma eğilimindedir.AbstractIn this study, the scope of export and import oriented growth hypothesis, export and imports' contribution to the dynamic of the Turkish GDP Growth have been investigated during the period between 1989 and 2007. According to the diagnoses which are found, export plays a dominant role while the economy is shifting from ressesion mode to expanding period. In order to continue this process, export and import together provides a great amount of contribution, while the contributions of export and import tend to decrease during the expanding period

Getting the phase consistent: The importance of phase description in balanced steady-state free precession MRI of multicompartment systems

Purpose: Determine the correct mathematical phase description for balanced steady-state free precession (bSSFP) signals in multicompartment systems. Theory and Methods: Based on published bSSFP signal models, two distinct phase descriptions can be formulated: one predicting the presence and the other predicting the absence of destructive interference effects in multicompartment systems. Numerical simulations of bSSFP signals of water and acetone were performed to evaluate the predictions of these two distinct phase descriptions. For experimental validation, bSSFP profiles were measured at 3T using phase-cycled bSSFP acquisitions performed in a phantom containing mixtures of water and acetone, which replicates a system with two signal components. Localized single voxel MRS was performed at 7T to determine the relative chemical-shift of the acetone-water mixtures. Results: Based on the choice of phase description, the simulated bSSFP profiles of water-acetone mixtures varied significantly, either displaying or lacking destructive interference effects, as predicted theoretically. In phantom experiments, destructive interference was consistently observed in the measured bSSFP profiles of water-acetone mixtures, an observation which excludes the phase description that predicts an absence of destructive interference. The connection between the choice of phase description and predicted observation enables an unambiguous experimental identification of the correct phase description for multicompartment bSSFP profiles, which is consistent with Bloch equations. Conclusion: The study emphasizes that consistent phase descriptions are crucial for accurately describing multi-compartment bSSFP signals, as incorrect phase descriptions result in erroneous predictions.Comment: Submitted to Magn. Reson. Me

A note on the values of the weighted q-Bernstein polynomials and modified q-Genocchi numbers with weight alpha and beta via the p-adic q-integral on Zp

The rapid development of q-calculus has led to the discovery of new generalizations of Bernstein polynomials and Genocchi polynomials involving q-integers. The present paper deals with weighted q-Bernstein polynomials and q-Genocchi numbers with weight alpha and beta. We apply the method of generating function and p-adic q-integral representation on Zp, which are exploited to derive further classes of Bernstein polynomials and q-Genocchi numbers and polynomials. To be more precise we summarize our results as follows, we obtain some combinatorial relations between q-Genocchi numbers and polynomials with weight alpha and beta. Furthermore, we derive an integral representation of weighted q-Bernstein polynomials of degree n on Zp. Also we deduce a fermionic p-adic q-integral representation of product weighted q-Bernstein polynomials of different degrees n1,n2,...on Zp and show that it can be written with q-Genocchi numbers with weight alpha and beta which yields a deeper insight into the effectiveness of this type of generalizations. Our new generating function possess a number of interesting properties which we state in this paper.Comment: 10 page