Incommensurate nodes in the energy spectrum of weakly coupled antiferromagnetic Heisenberg ladders

Heisenberg ladders are investigated using the bond-mean-field theory [M.Azzouz, Phys. Rev. B 48, 6136 (1993)]. The zero inter-ladder coupling energy gap, the uniform spin susceptibility and the nuclear magnetic resonance spin-relaxation rate are calculated as a function of temperature and magnetic field. For weakly coupled ladders, the energy spectrum vanishes at incommensurate wavevectors giving rise to nodes. As a consequence, the spin susceptibility becomes linear at low temperature. Our results for the single ladder successfully compare to experiments on SrCu_2O_3 and (VO)_2P_2O_7 materials and new predictions concerning the coupling to the magnetic field are made.Comment: 4 revtex pages, 3 figures available upon reques

Роман Ігоря Муратова “У сорочці народжений”: спроба аналізу

Ця стаття присвячена проблемі дослідження генезисних витоків та діалектиці становлення центрального героя роману Ігоря Муратова “У сорочці народжений” Федора Коляди та тих персонажів, які вплинули на розвиток його непересічного характеру. Відзначається високий рівень майстерності письменника, що виражається у яскравих, індивідуальних образах. Також розглядається короткий огляд тогочасного українського літературного процесу. Ґрунтовно проаналізовано не тільки персонажів, але й назву роману та назви усіх п’яти розділів. Ключові слова: час, місто, портрет, площина тексту, екстремальна ситуація, війна, натура.Эта статья посвящается проблеме исследования генезисных истоков и диалектике становления центрального героя романа Игоря Муратова “В сорочке рожденный” Федора Коляды и тех персонажей, которые повлияли на развитие его незаурядного характера. Отмечается высокий уровень мастерства писателя, что выражается в ярких, индивидуальных образах. Также подается короткий обзор украинского литературного процесса того времени. Тщательно проанализировано не только персонажи, а и название романа и названия всех пяти частей. Ключевые слова: время, город, портрет, пространство текста, экстремальная ситуация, война, натура.The article deals with the research of the genesis sources and development dialectics of Fedir Kolyada – the main hero of the novel “Born with a silver spoon in his mouth” (“U sorotchtzi narodzheny”) by Ihor Muratov – and other heroes, who influenced the progress of his outstanding character. The high level writer’s skill, embodied in bright, individual images, is marked off. The paper presents a brief review of the literary process of that period. It gives a deep analysis of not only the characters, but also the titles of the novel and its five chapters. Keywords: time, city, portrait, text level, extreme situation, war, nature

Tunable Superconducting Properties of a-NbSi Thin Films and Application to Detection in Astrophysics

We report on the superconducting properties of amorphous NbxSi1-x thin films. The normal-state resistance and critical temperatures can be separately adjusted to suit the desired application. Notably, the relatively low electron-phonon coupling of these films makes them good candidates for an "all electron bolometer" for Cosmological Microwave Background radiation detection. Moreover, this device can be made to suit both high and low impedance readouts

Microfaciès d’une lentille biohermale a la limite Eifelien/Givetien (‘Fondry Des Chiens’, Nismes, bord sud du synclinorium de Dinant)

Microfacies of a biohermal lens at the Eifelian.Givetian transition (‘Fondry des Chiens’, Nismes, southern border of the Dinant Synclinorium). The biohermal lens of the ‘Fondry des Chiens’ belongs to the Eifelian-Givetian transition beds near Nismes (southern flank of the Dinant basin). The lens is 64 m thick and composed of a stromatopore-coral framestone. It is overlain by restricted lagoonal algal and cyanophycean facies near the emersion, and overlies Udoteacean and coral-bryozoan coverstones forming the flanks of two other unexposed lenses. Two crinoidal soles stabilized by syntaxial cementation constitute the substratum of these lenses. The reefal sedimentation is regressive. The log is based on the succession of 10 carbonate microfacies (MF1-10, standard sequence). The deepest microfacies (MF1) is open marine at the upper limit of the storm waves and the dysphotic-euphotic boundary. The shallowest sediments were partly emerged (lagoonal sediments, MF10). The exposed reefal lens (rudstones and framestones, MF6-7) and the flanks (grainstones, floatstones and coverstones, MF3-4-5) of the two other lenses are preserved due to early isopachous intergranular cement in the original cavities of the framestones or ‘intramicritic’ (replacement of the matrix) cementation in the floatstones and coverstones. The similarity of the facies and their algal content suggest that the sedimentary model proposed at Wellin is applicable at Nismes. Sequential analysis points to a three steps regressive evolution of the sedimentation probably related to a discontinuous subidence. The sequences have similar thicknesses (sixty or so meters) and grade from the dysphotic-euphotic boundary estimated here around twenty meters deep to emersion. As for Wellin, the subsidence is thus much more important than the eustatic regression

Contour extracting networks in early extrastriate cortex

Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ?association field? proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour integration mechanisms. We used functional magnetic resonance imaging (fMRI) and population receptive field (pRF) analyses. We devised pRF mapping stimuli consisting of contours. We isolated the contribution of contour integration mechanisms to the pRF by manipulating the contour content. This stimulus manipulation led to systematic changes in pRF size. Whereas a bank of Gabor filters quantitatively explains pRF size changes in V1, only V2/V3 pRF sizes match the predictions of the association field. pRF size changes in later visual field maps, hV4, LO-1, and LO-2 do not follow either prediction and are probably driven by distinct classical receptive field properties or other extraclassical integration mechanisms. These pRF changes do not follow conventional fMRI signal strength measures. Therefore, analyses of pRF changes provide a novel computational neuroimaging approach to investigating neural interactions. We interpreted these results as evidence for neural interactions along co-oriented, cocircular receptive fields in the early extrastriate visual cortex (V2/V3), consistent with the notion of a contour association field

Generative adversarial networks: an overview

Generative adversarial networks (GANs) provide a way to learn deep representations without extensively annotated training data. They achieve this by deriving backpropagation signals through a competitive process involving a pair of networks. The representations that can be learned by GANs may be used in a variety of applications, including image synthesis, semantic image editing, style transfer, image superresolution, and classification. The aim of this review article is to provide an overview of GANs for the signal processing community, drawing on familiar analogies and concepts where possible. In addition to identifying different methods for training and constructing GANs, we also point to remaining challenges in their theory and application

Gap States in Dilute Magnetic Alloy Superconductors

We study states in the superconducting gap induced by magnetic impurities using self-consistent quantum Monte Carlo with maximum entropy and formally exact analytic continuation methods. The magnetic impurity susceptibility has different characteristics for T_{0} \alt T_{c0} and T_{0} \agt T_{c0} ($T_{0}$: Kondo temperature, $T_{c0}$: superconducting transition temperature) due to the crossover between a doublet and a singlet ground state. We systematically study the location and the weight of the gap states and the gap parameter as a function of $T_{0}/T_{c0}$ and the concentration of the impurities.Comment: 4 pages in ReVTeX including 4 encapsulated Postscript figure

Noninvasive Wireless Sensor PFMT Device for Pelvic Floor Muscle Training

[[abstract]]Urinary incontinence is a common problem among adults. Studies have shown up to 70% improvement in stress incontinence symptoms following appropriately performed pelvic floor exercise. This improvement is evident across all age groups. In this study, we cooperated with a doctor of the Department of Obstetrics and Gynecology, Taipei Veterans General Hospital, Taiwan. We developed a noninvasive device with the purpose of helping patients commence and perform pelvic floor muscle training (PFMT). This device consists of a PFMT device, an Arduino control board, a force sensor, a Bluetooth device, and an SD card. The objectives of this study are to train patients to inhibit detrusor contraction voluntarily and to contract periurethral muscles selectively. The system records and analyzes sensor data and provides voice prompts during PFMT exercise for patients at hospitals or their homes. Meanwhile, it tracks patients’ PFMT exercise at home, and doctors can contact patients for additional visitation(s) if necessary.[[incitationindex]]SCI[[booktype]]紙

Disulfide bonds reduce the toxicity of the amyloid fibrils formed by an extracellular protein

In a stable condition: Disulfide bonds stabilize folded proteins primarily by decreasing the entropic cost of folding. Such cross-links also reduce toxic aggregation by favoring the formation of highly structured amyloid fibrils (see picture). It is suggested that disulfide bonds in extracellular proteins were selected by evolutionary pressures because they decrease the propensity to form toxic aggregates. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Triple visual hemifield maps in a case of optic chiasm hypoplasia

In humans, each hemisphere comprises an overlay of two visuotopic maps of the contralateral visual field, one from each eye. Is the capacity of the visual cortex limited to these two maps or are plastic mechanisms available to host more maps? We determined the cortical organization of the visual field maps in a rare individual with chiasma hypoplasia, where visual cortex plasticity is challenged to accommodate three hemifield maps. Using high-resolution fMRI at 7T and diffusion-weighted MRI at 3T, we found three hemiretinal inputs, instead of the normal two, to converge onto the left hemisphere. fMRI-based population receptive field mapping of the left V1-V3 at 3T revealed three superimposed hemifield representations in the left visual cortex, i.e. two representations of opposing visual hemifields from the left eye and one right hemifield representation from the right eye. We conclude that developmental plasticity including the re-wiring of local intra- and cortico-cortical connections is pivotal to support the coexistence and functioning of three hemifield maps within one hemisphere