A Real Space Description of Field Induced Melting in the Charge Ordered Manganites: II. the Disordered Case

We study the effect of A site disorder on magnetic field induced melting of charge order (CO) in half doped manganites using a Monte-Carlo technique. Strong A-site disorder destroys CO even without an applied field. At moderate disorder, the zero field CO state survives but has several intriguing features in its field response. Our spatially resolved results track the broadening of the field melting transition due to disorder and explain the unusual dependence of the melting scales on bandwidth and disorder. In combination with our companion paper on field melting of charge order in clean systems we provide an unified understanding of CO melting across all half doped manganites.Comment: 9 pages, pdflatex, 10 embedded png fig

A Real Space Description of Magnetic Field Induced Melting in the Charge Ordered Manganites: I. The Clean Limit

We study the melting of charge order in the half doped manganites using a model that incorporates double exchange, antiferromagnetic superexchange, and Jahn-Teller coupling between electrons and phonons. We primarily use a real space Monte Carlo technique to study the phase diagram in terms of applied field $(h)$ and temperature $(T)$, exploring the melting of charge order with increasing $h$ and its recovery on decreasing $h$. We observe hysteresis in this response, and discover that the `field melted' high conductance state can be spatially inhomogeneous even without extrinsic disorder. The hysteretic response plays out in the background of field driven equilibrium phase separation. Our results, exploring $h$, $T$, and the electronic parameter space, are backed up by analysis of simpler limiting cases and a Landau framework for the field response. This paper focuses on our results in the `clean' systems, a companion paper studies the effect of cation disorder on the melting phenomena.Comment: 16 pages, pdflatex, 11 png fig

Study of the One- and Two-Band Models for Colossal Magnetoresistive Manganites Using the Truncated Polynomial Expansion Method

Considerable progress has been recently made in the theoretical understanding of the colossal magnetoresistance (CMR) effect in manganites. The analysis of simple models with two competing states and a resistor network approximation to calculate conductances has confirmed that CMR effects can be theoretically reproduced using non-uniform clustered states. In this paper, the recently proposed Truncated Polynomial Expansion method (TPEM) for spin-fermion systems is tested using the double-exchange one-band, with finite Hund coupling $J_{\rm H}$, and two-band, with infinite $J_{\rm H}$, models. Two dimensional lattices as large as 48$\times$48 are studied, far larger than those that can be handled with standard exact diagonalization (DIAG) techniques for the fermionic sector. The clean limit (i.e. without quenched disorder) is here analyzed in detail. Phase diagrams are obtained, showing first-order transitions separating ferromagnetic metallic from insulating states. A huge magnetoresistance is found at low temperatures by including small magnetic fields, in excellent agreement with experiments. However, at temperatures above the Curie transition the effect is much smaller confirming that the standard finite-temperature CMR phenomenon cannot be understood using homogeneous states. By comparing results between the two methods, TPEM and DIAG, on small lattices, and by analyzing the systematic behavior with increasing cluster sizes, it is concluded that the TPEM is accurate to handle realistic manganite models on large systems. Our results pave the way to a frontal computational attack of the colossal magnetoresistance phenomenon using double-exchange like models, on large clusters, and including quenched disorder.Comment: 14 pages, 17 figure

Kahramanmaraş’ta Organik Pamuk Üretim Olanaklarının Araştırılması

Organik pamuk tarımı ile ilgili bazı temel veriler elde etmek amacıyla yapılan bu proje 2001 yılında başlamış 2006 yılında sonuçlandırılmıştır. Yürütülen çalışma ile pamuk bitkisinin yaprak tüylülüğü ile bitki besleme tekniğinin görülen zararlıların yoğunluğunu etkilediği belirlenmiştir. Yapılan çalışmada; zararlılar klasik üretim sisteminin uygulandığı parsellerde diğer sistemlerden daha yüksek yoğunlukta tespit edilirken bunu organik ve kontrol üretim sistemlerinin izlediği belirlenmiştir. Empoasca decipiens, yaprakları tüysüz veya az tüylü olan Erşan-92 pamuk çeşidinde diğerlerine göre daha fazla yoğunlukta görülürken; yaprakları daha tüylü olan Stoneville 453 pamuk çeşidinde daha düşük yoğunlukta tespit edilmiştir. İlimiz pamuk ekim alanlarının önemli problemlerinden biri solgunluk hastalığıdır. Yaprak ve gövde kesitine göre belirlenen hastalık şiddeti organik üretim sistemi parsellerinde daha düşük görülmüş bunu kontrol ve klasik üretim sistemleri izlemiştir. Hastalık şiddeti değerlerine bakıldığında münavebesiz parsellerde münavebe yapılan parsellere göre daha yüksek görülmüştür. Projede yabancı otlar ile ilgili yapılan çalışmada Sorghum halepense (Geliç), Xanthium strumarium L.(Pıtrak), Convolvulus arvensis L.(Tarla Sarmaşığı), Cyperus spp.(Topalak) ve Echinocloa colonum(Benekli Darıcan)’ın klasik parsellerde; Amaranthus retroflexus L.(Horoz İbiği), Solanum nigrum L.(Köpek Üzümü) ve Portulaca oleracea L.(Semiz Otu)’nın ise organik parsellerde daha yoğun olarak görüldüğü tespit edilmiştir. Araştırmada ortalama verim değerlerinin münavebe yapılan parsellerde münavebesiz parsellere göre daha yüksek olduğu ayrıca klasik üretimin organik üretim yapılan parsellere göre daha yüksek verim verdiği tespit edilmiştir. Çalışmanın ekonomik analizinde net gelirler ortalamasına bakıldığında münavebeli parsellerin münavebesize göre, klasik parsellerinde organiğe göre daha yüksek net gelir sağladığı tespit edilmiştir

Turner syndrome and associated problems in turkish children: A multicenter study

Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population. Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014. Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosi) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto’s thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%. Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespan. © Journal of Clinical Research in Pediatric Endocrinology

Bilayer manganites: polarons in the midst of a metallic breakdown

The exact nature of the low temperature electronic phase of the manganite materials family, and hence the origin of their colossal magnetoresistant (CMR) effect, is still under heavy debate. By combining new photoemission and tunneling data, we show that in La{2-2x}Sr{1+2x}Mn2O7 the polaronic degrees of freedom win out across the CMR region of the phase diagram. This means that the generic ground state is that of a system in which strong electron-lattice interactions result in vanishing coherent quasi-particle spectral weight at the Fermi level for all locations in k-space. The incoherence of the charge carriers offers a unifying explanation for the anomalous charge-carrier dynamics seen in transport, optics and electron spectroscopic data. The stacking number N is the key factor for true metallic behavior, as an intergrowth-driven breakdown of the polaronic domination to give a metal possessing a traditional Fermi surface is seen in the bilayer system.Comment: 7 pages, 2 figures, includes supplementary informatio

Dissolution Control of Mg by Cellulose Acetate–Polyelectrolyte Membranes

Cellulose acetate (CA)-based membranes are used for Mg dissolution control: the permeability of the membrane is adjusted by additions of the polyelectrolyte, poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA). Spin-coated films were characterized with FT-IR, and once exposed to an aqueous solution the film distends and starts acting as a membrane which controls the flow of ions and H2 gas. Electrochemical measurements (linear sweep voltammograms, open-circuit potential, and polarization) show that by altering the CA:PDMAEMA ratio the dissolution rate of Mg can be controlled. Such a control over Mg dissolution is crucial if Mg is to be considered as a viable, temporary biomedical implant material. Furthermore, the accumulation of corrosion products between the membrane and the sample diminishes the undesirable effects of high local pH and H2 formation which takes place during the corrosion process.Peer reviewe

XVI. Asırda Dini Meşruiyet ile Reel Politik Arasında Osmanlı Dış İlişkileri

This article analyzes the conduct of the foreign policy of the Ottoman Empire and its compatibility with state ideology in the sixteenth century. It attempts to point out different ways the Ottomans used religious or political discourse to justify different policies. In particular, it focuses on the ways the Ottoman Empire dealt with the Habsburg and Safavid Empires, which exemplified two ideologically different struggles for the Ottoman Empire. It compares how chronicles and official documents responded to particular events, to understand how they prescribed and projected foreign relations differently. This study contends that on the one hand, religious ideology shaped and regulated Ottoman external relations, but on the other the Ottoman Empire also reconfigured religious ideology about jihad and developed new ideological arguments for political expediency, to relieve tension between the ideology and the reality.Bu çalışma, XVI. asırda Osmanlı İmparatorluğu’nun dış politikasının gidişatını ve devlet ideolojisi ile uyumluluğunu incelemekte ve Osmanlıların farklı politikalarını haklı çıkarmak için ne tür dini veya siyasi söylem kullandıklarını anlamaya çalışmaktadır. Söz konusu çalışma, özellikle, ideolojik olarak Osmanlılar için iki farklı mücadeleyi örnekleyen Habsburg ve Safevi İmparatorlukları ile Osmanlı İmparatorluğu arasındaki ilişkilere odaklanmaktadır. Bu çalışma, aynı zamanda, Osmanlı kroniklerinin ve resmi belgelerinin belirli olaylara nasıl tepki verdiklerini ve dış ilişkileri nasıl farklı şekilde yansıttıklarını incelemektedir. Ayrıca, bu çalışma, bir yandan dini ideolojinin Osmanlı dış ilişkilerini nasıl şekillendirdiğini ve düzenlediğini, ancak diğer yandan Osmanlı Devleti’nin ideoloji ile gerçeklik arasındaki gerilimi azaltmak için dini ideolojiyi nasıl yeniden yapılandırdığını ve yeni ideolojik argümanlar geliştirdiğini analiz etmektedir

Приклади завдань для позакласної роботи з інформатики у початковій школі

У статті коротко описана методика проведення позакласної роботи з інформатики у початковій школі