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Ho-Kun Sung, Tian Qiang, Zhao Yao, Yang Li, Qun Wu, Hee-Kwan Lee, Bum-Doo Park, Woong-Sun Lim, Kyung-Ho Park, Cong Wang
This study presents a detailed fabrication method, together with validation, discussion, and analysis, for state-of-the-art silicon carbide (SiC) etching of vertical and bevelled structures by using inductively coupled plasma reactive ion etching (ICP-RIE) for microelectronic applications. Applying different gas mixtures, a maximum bevel angle of 87° (almost vertical), large-angle bevels ranging from 40° to 80°, and small-angel bevels ranging from 7° to 17° were achieved separately using distinct gas mixtures at different ratios...
June 20, 2017: Scientific Reports
Ron D Frostig, Cynthia H Chen-Bee, Brett A Johnson, Nathan S Jacobs
This review brings together a collection of studies that specifically use wide-field high-resolution mesoscopic level imaging techniques (intrinsic signal optical imaging; voltage-sensitive dye optical imaging) to image the cortical point spread (PS): the total spread of cortical activation comprising a large neuronal ensemble evoked by spatially restricted (point) stimulation of the sensory periphery (e.g., whisker, pure tone, point visual stimulation). The collective imaging findings, combined with supporting anatomical and electrophysiological findings, revealed some key aspects about the PS including its very large (radius of several mm) and relatively symmetrical spatial extent capable of crossing cytoarchitectural borders and trespassing into other cortical areas; its relationship with underlying evoked subthreshold activity and underlying anatomical system of long-range horizontal projections within gray matter, both also crossing borders; its contextual modulation and plasticity; the ability of its relative spatiotemporal profile to remain invariant to major changes in stimulation parameters; its potential role as a building block for integrative cortical activity; and its ubiquitous presence across various cortical areas and across mammalian species...
July 2017: Neurophotonics
M H Yang, J H Li, B X Liu
In the present study, atomistic simulation reveals that the microscopic mechanism of the relaxation dynamics in amorphous materials is governed by the activating atoms that jump more than half of the average nearest neighbor distance within a given time. Based on the unsupervised machine-learning algorithm, hierarchical clustering analysis shows that the activating atoms are excited in a cooperative and avalanche-like model to form activating units. Correlation analysis suggests that large free volumes facilitate the formation of activating atoms...
June 19, 2017: Physical Chemistry Chemical Physics: PCCP
Bin Liu, Fan Yang, Kuo-Chen Chou
Involved with important cellular or gene functions and implicated with many kinds of cancers, piRNAs, or piwi-interacting RNAs, are of small non-coding RNA with around 19-33 nt in length. Given a small non-coding RNA molecule, can we predict whether it is of piRNA according to its sequence information alone? Furthermore, there are two types of piRNA: one has the function of instructing target mRNA deadenylation, and the other does not. Can we discriminate one from the other? With the avalanche of RNA sequences emerging in the postgenomic age, it is urgent to address the two problems for both basic research and drug development...
June 16, 2017: Molecular Therapy. Nucleic Acids
Konstantin V Krutitsky, Andreas Osterloh, Ralf Schützhold
We study the ground-state entanglement in the quantum Ising model with nearest neighbor ferromagnetic coupling J and find a sequential increase of entanglement depth d with growing J. This entanglement avalanche starts with two-point entanglement, as measured by the concurrence, and continues via the three-tangle and four-tangle, until finally, deep in the ferromagnetic phase for J = ∞, arriving at a pure L-partite (GHZ type) entanglement of all L spins. Comparison with the two, three, and four-point correlations reveals a similar sequence and shows strong ties to the above entanglement measures for small J...
June 16, 2017: Scientific Reports
Javier G Orlandi, Jaume Casademunt
We introduce a coarse-grained stochastic model for the spontaneous activity of neuronal cultures to explain the phenomenon of noise focusing, which entails localization of the noise activity in excitable networks with metric correlations. The system is modeled as a continuum excitable medium with a state-dependent spatial coupling that accounts for the dynamics of synaptic connections. The most salient feature is the emergence at the mesoscale of a vector field V(r), which acts as an advective carrier of the noise...
May 2017: Physical Review. E
Laurent Ponson, Nadjime Pindra
The dynamics of a planar crack propagating within a brittle disordered material is investigated numerically. The fracture front evolution is described as the depinning of an elastic line in a random field of toughness. The relevance of this approach is critically tested through the comparison of the roughness front properties, the statistics of avalanches, and the local crack velocity distribution with experimental results. Our simulations capture the main features of the fracture front evolution as measured experimentally...
May 2017: Physical Review. E
Antoni Planes, Eduard Vives
Martensitic transitions take place intermittently as a sequence of avalanches, which are accompanied by the emission of acoustic waves. The study of this acoustic emission (AE) reveals the scale-free nature of the avalanches. In a number of shape memory materials undergoing a martensitic transition it has been found that, in spite of the relatively low hysteresis, the dynamics of forward and reverse transitions are different, which may explain the fact that the AE activity is different in both forward and reverse transitions...
June 12, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Xinxin Zhou, Chee Hing Tan, Shiyong Zhang, Manuel Moreno, Shiyu Xie, Salman Abdullah, Jo Shien Ng
When using avalanche photodiodes (APDs) in applications, temperature dependence of avalanche breakdown voltage is one of the performance parameters to be considered. Hence, novel materials developed for APDs require dedicated experimental studies. We have carried out such a study on thin Al1-x Ga x As0.56Sb0.44 p-i-n diode wafers (Ga composition from 0 to 0.15), plus measurements of avalanche gain and dark current. Based on data obtained from 77 to 297 K, the alloys Al1-x Ga x As0.56Sb0.44 exhibited weak temperature dependence of avalanche gain and breakdown voltage, with temperature coefficient approximately 0...
May 2017: Royal Society Open Science
Horst Zimmermann, Bernhard Steindl, Michael Hofbauer, Reinhard Enne
Experimental results of a single-photon avalanche diode (SPAD) based optical fiber receiver integrated in 0.35 µm PIN-photodiode CMOS technology are presented. To cope with the parasitic effects of SPADs an array of four receivers is implemented. The SPADs consist of a multiplication zone and a separate thick absorption zone to achieve a high photon detection probability (PDP). In addition cascoded quenchers allow to use a quenching voltage of twice the usual supply voltage, i.e. 6.6 V instead of 3.3 V, in order to increase the PDP further...
June 1, 2017: Scientific Reports
Ze-Sheng Chen, Ben Ma, Xiang-Jun Shang, Hai-Qiao Ni, Jin-Liang Wang, Zhi-Chuan Niu
A pronounced high count rate of single-photon emission at the wavelength of 1.3 μm that is capable of fiber-based quantum communication from InAs/GaAs bilayer quantum dots coupled with a micropillar (diameter ~3 μm) cavity of distributed Bragg reflectors was investigated, whose photon extraction efficiency has achieved 3.3%. Cavity mode and Purcell enhancement have been observed clearly in microphotoluminescence spectra. At the detection end of Hanbury-Brown and Twiss setup, the two avalanched single-photon counting modules record a total count rate of ~62,000/s; the time coincidence counting measurement demonstrates single-photon emission, with the multi-photon emission possibility, i...
December 2017: Nanoscale Research Letters
Bruno Del Papa, Viola Priesemann, Jochen Triesch
Many experiments have suggested that the brain operates close to a critical state, based on signatures of criticality such as power-law distributed neuronal avalanches. In neural network models, criticality is a dynamical state that maximizes information processing capacities, e.g. sensitivity to input, dynamical range and storage capacity, which makes it a favorable candidate state for brain function. Although models that self-organize towards a critical state have been proposed, the relation between criticality signatures and learning is still unclear...
2017: PloS One
Nicky Nicolson, Katherine Challis, Allan Tucker, Sandra Knapp
BACKGROUND: At the Nomenclature Section of the XVIII International Botanical Congress in Melbourne, Australia (IBC), the botanical community voted to allow electronic publication of nomenclatural acts for algae, fungi and plants, and to abolish the rule requiring Latin descriptions or diagnoses for new taxa. Since the 1st January 2012, botanists have been able to publish new names in electronic journals and may use Latin or English as the language of description or diagnosis. RESULTS: Using data on vascular plants from the International Plant Names Index (IPNI) spanning the time period in which these changes occurred, we analysed trajectories in publication trends and assessed the impact of these new rules for descriptions of new species and nomenclatural acts...
May 25, 2017: BMC Evolutionary Biology
Christian Wöber
BACKGROUND: Trigeminal autonomic cephalalgias (TACs) comprise cluster headache, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks, and hemicrania continua. In some cases, trigeminal neuralgia (TN, "tic douloureux") or TN-like pain may co-occur with TACs. AIM: This article will review the co-occurrence and overlap of TACs and tics in order to contribute to a better understanding of the issue and an improved management of the patients. METHODS: For performing a systematic literature review Pubmed was searched using a total of ten terms...
May 19, 2017: Headache
Gerald Hahn, Adrian Ponce-Alvarez, Cyril Monier, Giacomo Benvenuti, Arvind Kumar, Frédéric Chavane, Gustavo Deco, Yves Frégnac
Brain activity displays a large repertoire of dynamics across the sleep-wake cycle and even during anesthesia. It was suggested that criticality could serve as a unifying principle underlying the diversity of dynamics. This view has been supported by the observation of spontaneous bursts of cortical activity with scale-invariant sizes and durations, known as neuronal avalanches, in recordings of mesoscopic cortical signals. However, the existence of neuronal avalanches in spiking activity has been equivocal with studies reporting both its presence and absence...
May 2017: PLoS Computational Biology
Bastien Soulé, Brice Lefèvre, Eric Boutroy
In France, there is a growing enthusiasm for outdoor sports and recreation. In the meantime, the risk of both severe and frequent injury associated with active pursuits in mountain areas is acknowledged. This paper tackles accidents related to mountain sports, with a focus on three critical activities: hiking, mountaineering and ski touring. The aim consists of estimating the actual number of accidents (whether they entailed deaths or injuries) in the three above-mentioned activities. In order to align the information collected, then provide estimations based on the reasoned crossing of these secondary data, we consulted and summarised all the databases available on the French territory...
August 2017: European Journal of Sport Science
Madubuike Umunna Anyanwu, Rosemary Chinazam Okoye
Antimicrobial resistance (AMR) is currently one of the major threats facing mankind. The emergence and rapid spread of multi- and pan-drug-resistant organisms (such as vancomycin-, methicillin-, extended-spectrum β-lactam-, carbapenem- and colistin-resistant organisms) has put the world in a dilemma. The health and economic burden associated with AMR on a global scale are dreadful. Available antimicrobials have been misused and are almost ineffective with some of these drugs associated with dangerous side effects in some individuals...
April 2017: Journal of Intercultural Ethnopharmacology
Xiumin Li, Qing Chen, Fangzheng Xue
In recent years, an increasing number of studies have demonstrated that networks in the brain can self-organize into a critical state where dynamics exhibit a mixture of ordered and disordered patterns. This critical branching phenomenon is termed neuronal avalanches. It has been hypothesized that the homeostatic level balanced between stability and plasticity of this critical state may be the optimal state for performing diverse neural computational tasks. However, the critical region for high performance is narrow and sensitive for spiking neural networks (SNNs)...
June 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Prabodh Shukla, Diana Thongjaomayum
We present general criteria for the occurrence of infinite avalanches and critical hysteresis in the zero-temperature nonequilibrium random-field Ising model on a Bethe lattice. Drawing upon extant results as well as a result on a dilute four-coordinated (z=4) lattice, we show that diverging avalanches can occur if an arbitrarily small fraction of sites on a spanning cluster have connectivity z≥4.
April 2017: Physical Review. E
Rianne de Jong, Song-Chuan Zhao, Devaraj van der Meer
After a raindrop impacts on a granular bed, a crater is formed as both drop and target deform. After an initial, transient, phase in which the maximum crater depth is reached, the crater broadens outwards until a final steady shape is attained. By varying the impact velocity of the drop and the packing density of the bed, we find that avalanches of grains are important in the second phase and hence affect the final crater shape. In a previous paper, we introduced an estimate of the impact energy going solely into sand deformation and here we show that both the transient and final crater diameter collapse with this quantity for various packing densities...
April 2017: Physical Review. E
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