Ferroelectricity in the Magnetic E-Phase of Orthorhombic Perovskites

We show that the symmetry of the spin zigzag chain E phase of the orthorhombic perovskite manganites and nickelates allows for the existence of a finite ferroelectric polarization. The proposed microscopic mechanism is independent of spin-orbit coupling. We predict that the polarization induced by the E-type magnetic order can potentially be enhanced by up to two orders of magnitude with respect to that in the spiral magnetic phases of TbMnO3 and similar multiferroic compounds.Comment: 4 pages, 2 figures, somewhat changed emphases, accepted to PR

The state of the art development of AHP (1979-2017): A literature review with a social network analysis

Although many papers describe the evolution of the analytic hierarchy process (AHP), most adopt a subjective approach. This paper examines the pattern of development of the AHP research field using social network analysis and scientometrics, and identifies its intellectual structure. The objectives are: (i) to trace the pattern of development of AHP research; (ii) to identify the patterns of collaboration among authors; (iii) to identify the most important papers underpinning the development of AHP; and (iv) to discover recent areas of interest. We analyse two types of networks: social networks, that is, co-authorship networks, and cognitive mapping or the network of disciplines affected by AHP. Our analyses are based on 8441 papers published between 1979 and 2017, retrieved from the ISI Web of Science database. To provide a longitudinal perspective on the pattern of evolution of AHP, we analyse these two types of networks during the three periods 1979?1990, 1991?2001 and 2002?2017. We provide some basic statistics on AHP journals and researchers, review the main topics and applications of integrated AHPs and provide direction for future research by highlighting some open questions

Dynamics of the chiral phase transition from AdS/CFT duality

We use Lorentzian signature AdS/CFT duality to study a first order phase transition in strongly coupled gauge theories which is akin to the chiral phase transition in QCD. We discuss the relation between the latent heat and the energy (suitably defined) of the component of a D-brane which lies behind the horizon at the critical temperature. A numerical simulation of a dynamical phase transition in an expanding, cooling Quark-Gluon plasma produced in a relativistic collision is carried out.Comment: 30 pages, 5 figure

3D segmentation of intervertebral discs: from concept to the fabrication of patient-specific scaffolds

Aim: To develop a methodology for producing patient-specific scaffolds that mimic the annulus fibrosus (AF) of the human intervertebral disc (IVD) by means of combining magnetic resonance imaging (MRI) and 3D bioprinting. Methods: In order to obtain the AF 3D model from patientâ s volumetric MRI dataset, the RheumaSCORE segmentation software was used. Polycaprolactone scaffolds with three different internal architectures were fabricated by 3D bioprinting, and characterized by micro-computed tomography. Results: The demonstrated methodology of a geometry reconstruction pipeline enabled to successfully obtain an accurate AF model and 3D print patient-specific scaffolds with different internal architectures. Conclusion: The results guide us towards patient-specific IVD tissue engineering as demonstrated a way of manufacturing personalized scaffolds using patient's MRI data.The authors would like to acknowledge the financial support provided by the Portuguese Foundation for Science and Technology (FCT) through the project EPIDisc (UTAPEXPL/BBB-ECT/0050/2014), funded in the Framework of the ‘International Collaboratory for Emerging Technologies, CoLab’, UT justin|Portugal Program. FCT is also acknowledged for the PhD scholarship attributed to IF Cengiz (SFRH/ BD/99555/2014) and the financial support provided to J Silva-Correia (SFRH/BPD/100590/2014 and IF/00115/2015). JM Oliveira also thanks the FCT for the funds provided under the program Investigador FCT (IF/00423/2012 and IF/01285/2015). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.info:eu-repo/semantics/publishedVersio

Stimulation of Na⁺/H⁺ Exchanger Isoform 1 Promotes Microglial Migration

Regulation of microglial migration is not well understood. In this study, we proposed that Na+/H+ exchanger isoform 1 (NHE-1) is important in microglial migration. NHE-1 protein was co-localized with cytoskeletal protein ezrin in lamellipodia of microglia and maintained its more alkaline intracellular pH (pHi). Chemoattractant bradykinin (BK) stimulated microglial migration by increasing lamellipodial area and protrusion rate, but reducing lamellipodial persistence time. Interestingly, blocking NHE-1 activity with its potent inhibitor HOE 642 not only acidified microglia, abolished the BK-triggered dynamic changes of lamellipodia, but also reduced microglial motility and microchemotaxis in response to BK. In addition, NHE-1 activation resulted in intracellular Na+ loading as well as intracellular Ca2+ elevation mediated by stimulating reverse mode operation of Na+/Ca2+ exchange (NCXrev). Taken together, our study shows that NHE-1 protein is abundantly expressed in microglial lamellipodia and maintains alkaline pHi in response to BK stimulation. In addition, NHE-1 and NCXrev play a concerted role in BK-induced microglial migration via Na+ and Ca2+ signaling. © 2013 Shi et al

Correlative Information Maximization: A Biologically Plausible Approach to Supervised Deep Neural Networks without Weight Symmetry

The backpropagation algorithm has experienced remarkable success in training large-scale artificial neural networks; however, its biological plausibility has been strongly criticized, and it remains an open question whether the brain employs supervised learning mechanisms akin to it. Here, we propose correlative information maximization between layer activations as an alternative normative approach to describe the signal propagation in biological neural networks in both forward and backward directions. This new framework addresses many concerns about the biological-plausibility of conventional artificial neural networks and the backpropagation algorithm. The coordinate descent-based optimization of the corresponding objective, combined with the mean square error loss function for fitting labeled supervision data, gives rise to a neural network structure that emulates a more biologically realistic network of multi-compartment pyramidal neurons with dendritic processing and lateral inhibitory neurons. Furthermore, our approach provides a natural resolution to the weight symmetry problem between forward and backward signal propagation paths, a significant critique against the plausibility of the conventional backpropagation algorithm. This is achieved by leveraging two alternative, yet equivalent forms of the correlative mutual information objective. These alternatives intrinsically lead to forward and backward prediction networks without weight symmetry issues, providing a compelling solution to this long-standing challenge

Biologically-Plausible Determinant Maximization Neural Networks for Blind Separation of Correlated Sources

Extraction of latent sources of complex stimuli is critical for making sense of the world. While the brain solves this blind source separation (BSS) problem continuously, its algorithms remain unknown. Previous work on biologically-plausible BSS algorithms assumed that observed signals are linear mixtures of statistically independent or uncorrelated sources, limiting the domain of applicability of these algorithms. To overcome this limitation, we propose novel biologically-plausible neural networks for the blind separation of potentially dependent/correlated sources. Differing from previous work, we assume some general geometric, not statistical, conditions on the source vectors allowing separation of potentially dependent/correlated sources. Concretely, we assume that the source vectors are sufficiently scattered in their domains which can be described by certain polytopes. Then, we consider recovery of these sources by the Det-Max criterion, which maximizes the determinant of the output correlation matrix to enforce a similar spread for the source estimates. Starting from this normative principle, and using a weighted similarity matching approach that enables arbitrary linear transformations adaptable by local learning rules, we derive two-layer biologically-plausible neural network algorithms that can separate mixtures into sources coming from a variety of source domains. We demonstrate that our algorithms outperform other biologically-plausible BSS algorithms on correlated source separation problems.Comment: NeurIPS 2022, 37 page

Rekreasyon eğilimlerindeki değişime zamanın etkisinin saptanması: Artvin-Kafkasör Ormanı rekreasyon alanı örneği

Artvin (Türkiye) kent merkezine yakın olan Kafkasör Ormanı önemli bir rekreasyon alanıdır. Alanda her yıl Temmuz ayında “Kafkasör Festivali” düzenlenmektedir. Ancak festivaller esnasında alan aşırı yoğun kullanıma maruz kalmakta, düzensiz kullanımlar ve donatıların eksikliği nedeniyle zarar görmektedir. Yapılan festival etkinliklerinin yoğunluğu nedeniyle alan ihtiyaca cevap verememektedir. Daha önce saptanan ziyaretçi ihtiyaçlarının planlamada dikkate alınmaması nedeniyle ziyaretçi isteklerinin yeniden belirlenmesi gerekmektedir. Araştırmada alanın festival zamanında yoğun kullanıma hazırlıksız yakalanması ve bilinçsiz kullanımdan dolayı zarar görmesini önlemek ve alanı korumak amacıyla araştırma alanı toplum istekleri yönünden incelenmiştir. Cengiz (1996) tarafından yapılan anket sonuçları ile 2006 yılında yapılan anket sonuçları karşılaştırılmıştır. Geçen on yıllık süreçte zaman değişiminin rekreasyon eğilimlerine etkisinin olup olmadığı araştırılarak kullanım isteklerinin belirlenmesi amaçlanmıştır. Yapılan çalışma aynı zamanda daha önce ortaya konulan bilimsel sonuçların yerel yönetimler tarafından uygulanmadığını göstermektedir. 1996 ve 2006 yıllarında yapılan anketlerde rekreasyonel isteklerdeki değişimleri karşılaştırmak için Minitab 13.0 istatistik paket programında “z oran testi” kullanılmıştır. Araştırmada bulgular göstermiştir ki rekreasyon ve turizm aktivitelerinde geçen on yıllık süreçte alanı kullanan ziyaretçi profilinde, isteklerde ve tercihlerde büyük oranda bir değişme görülmemiştir. On yıllık süreç içinde yerel halkın isteklerinin hiçbiri gerçekleşmemiştir. Ayrıca yerel yönetimlerin yapılan bilimsel araştırmaların sonuçlarından yararlanmadığı ve problemleri çözmediği saptanmıştır

Influence of Urban Green Spaces and Social Reinforcement Elements in Home Purchasing: The Case of Canakkale City, Turkey

Under present market conditions, the price of land is constantly rising, and cities are being shaped accordingly. Because the allocation of land for construction is carried out with the expense of land in mind, this has led to an increasing reduction of green areas in urban planning. As a result, we are witnessing a decrease in the quality of today's urban environment and the commencement of destruction of a livable urban environment. This study evaluated environmental factors such as green spaces and social reinforcement that raise the quality of urban life but which, due to being unrepresented openly on the market, are consumed as if they are free goods, or ignored. We investigated this issue according to four environmental attributes considered by individuals when buying a house or home in the city of Canakkale; namely, outdoor furniture elements, recreational areas, transportation, and psychological influences. The relationship between garden size and housing prices in the city center was also examined. The findings revealed that, when individuals were purchasing housing in the city, they were influenced by environmental attributes and, according to the quality of the environmental attributes relating to the house, the price increased proportionally

Konut Satın Alımında Kentsel Açık-Yeşil Alanlar ve Sosyal Donatı Elemanlarının İncelenmesi: Çanakkale Kent Merkezi Örneği

Günümüzde pazar koşulları düşünüldüğünde arazi fiyatları büyük oranda artmakta ve kentler buna göre şekillenmektedir. Arazi fiyatlarının pahalı olması nedeniyle yapılaşmaya ayrılması, kent planlamasında yeşil alanların gittikçe azalmasına neden olmaktadır. Bunun sonucunda kentsel çevre niteliği azalarak, yaşanabilir kentsel çevreler yok olmaya başlamıştır. Bu araştırmada, yeşil alanlar ve sosyal donatı elemanları gibi kent insanının yaşam kalitesini yükselten fakat piyasada açık olarak temsil edilemedikleri için serbest mal olarak tüketilen ya da göz ardı edilen, çevresel unsurlar değerlendirilmeye çalışılmıştır. Çanakkale kent merkezinde bireylerin konut satın alırken dikkat ettikleri çevresel özellikler; donatı elemanları, rekreasyon alanları, ulaşım durumu ve psikolojik etkilere göre araştırılmıştır. Ayrıca kent merkezindeki konut fiyatları ile bahçeleri arasındaki ilişki incelenmiştir. Araştırma sonucunda Çanakkale kent merkezinde bireylerin konut satın alırken çevresel özelliklerden etkilendiği ve konutun bulunduğu çevrenin kalitesine göre fiyatının artmakta olduğu saptanmıştı