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Laure Margueritte, Petar Markov, Lionel Chiron, Jean-Philippe Starck, Catherine Vonthron-Sã nà Cheau, Mã Lanie Bourjot, Marc-Andrà Delsuc
Liquid state NMR is a powerful tool for the analysis of complex mixtures of unknown molecules. This capacity has been used in many analytical approaches: metabolomics, identification of active compounds in natural extracts, characterization of species, and such studies require the acquisition of many diverse NMR measurements on series of samples. While acquisition can easily be performed automatically, the number of NMR experiments involved in these studies increases very rapidly and this data avalanche requires to resort to automatic processing and analysis...
November 20, 2017: Magnetic Resonance in Chemistry: MRC
Agnes Weiss, Helmut Weiss
Small photovoltaic plants in private ownership are typically rated at 5 kW (peak). The panels are mounted on roofs at a decline angle of 20° to 45°. In winter time, a dense layer of snow at a width of e.g., 10 cm keeps off solar radiation from the photovoltaic cells for weeks under continental climate conditions. Practically, no energy is produced over the time of snow coverage. Only until outside air temperature has risen high enough for a rather long-time interval to allow partial melting of snow; the snow layer rushes down in an avalanche...
November 16, 2017: Environmental Science and Pollution Research International
Pu-Feng Du, Wei Zhao, Yang-Yang Miao, Le-Yi Wei, Likun Wang
With the avalanche of biological sequences in public databases, one of the most challenging problems in computational biology is to predict their biological functions and cellular attributes. Most of the existing prediction algorithms can only handle fixed-length numerical vectors. Therefore, it is important to be able to represent biological sequences with various lengths using fixed-length numerical vectors. Although several algorithms, as well as software implementations, have been developed to address this problem, these existing programs can only provide a fixed number of representation modes...
November 14, 2017: International Journal of Molecular Sciences
Ching-Wei Lin, Hailing Yang, Stephen R Sanchez, Weiqun Mao, Lan Pang, Kathleen Mary Beckingham, Robert C Bast, R Bruce Weisman
Biocompatible composites of single-walled carbon nanotubes in Matrigel have been surgically implanted into mouse ovaries and then noninvasively detected and located in the first in vivo demonstration of spectral triangulation. This optical method deduces the three-dimensional position of a short-wave IR emission source from the wavelength-dependent attenuation of fluorescence in tissues. Measurements were performed with a second-generation optical scanner that uses an LED matrix emitting at 736 nm for diffuse specimen excitation...
November 13, 2017: ACS Applied Materials & Interfaces
Peng Bai, Y H Zhang, W Z Shen
High performance single photon detector at the wavelength of 1550 nm has drawn wide attention and achieved vast improvement due to its significant application in quantum information, quantum key distribution, as well as cosmology. A novel infrared up-conversion single photon detector (USPD) at 1550 nm was proposed to work in free-running regime based on the InGaAs/ InP photodetector (PD)- GaAs/AlGaAs LED up-converter and Si single photon avalanche diode (SPAD). In contrast to conventional In0.53Ga0.47As SPAD, the USPD can suppress dark count rate and afterpulsing efficiently without sacrificing the photon detection efficiency (PDE)...
November 10, 2017: Scientific Reports
Beatrice Ruta, Eloi Pineda, Zach Evenson
Since their discovery in the 1960s, metallic glasses have continuously attracted much interest across the physics and materials science communities. In the forefront are their unique properties, which hold the alluring promise of broad application in fields as diverse as medicine, environmental science and engineering. However, a major obstacle to their wide-spread commercial use is their inherent temporal instability arising from underlying relaxation processes that can dramatically alter their physical properties...
November 9, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Jesús Espinal-Enríquez, Daniel González-Terán, Enrique Hernández-Lemus
Understanding the general principles underlying genetic regulation in eukaryotes is an incomplete and challenging endeavor. The lack of experimental information regarding the regulation of the whole set of transcription factors and their targets in different cell types is one of the main reasons to this incompleteness. So far, there is a small set of curated known interactions between transcription factors and their downstream genes. Here, we built a transcription factor network for human monocytic THP-1 myeloid cells based on the experimentally curated FANTOM4 database where nodes are genes and the experimental interactions correspond to links...
2017: International Journal of Genomics
Shan Yu, Tiago L Ribeiro, Christian Meisel, Samantha Chou, Andrew Mitz, Richard Saunders, Dietmar Plenz
Sensory events, cognitive processing and motor actions correlate with transient changes in neuronal activity. In cortex, these transients form widespread spatiotemporal patterns with largely unknown statistical regularities. Here, we show that activity associated with behavioral events carry the signature of scale-invariant spatiotemporal clusters, neuronal avalanches. Using high-density microelectrode arrays in nonhuman primates, we recorded extracellular unit activity and the local field potential (LFP) in premotor and prefrontal cortex during motor and cognitive tasks...
November 8, 2017: ELife
Ivan Prochazka, Jan Kodet, Johann Eckl, Josef Blazej
We are reporting on the design, construction, and performance of a photon counting detector system, which is based on single photon avalanche diode detector technology. This photon counting device has been optimized for very high timing resolution and stability of its detection delay. The foreseen application of this detector is laser ranging of space objects, laser time transfer ground to space and fundamental metrology. The single photon avalanche diode structure, manufactured on silicon using K14 technology, is used as a sensor...
October 2017: Review of Scientific Instruments
Zbigniew Czechowski, Agnieszka Budek
Two statistically stationary states with power-law scaling of avalanches are found in a simple 1 D cellular automaton. Features of the fixed points, the spiral saddle and the saddle with index 1, are investigated. The migration of states of the automaton between these two self-organized criticality states is demonstrated during evolution of the system in computer simulations. The automaton, being a slowly driven system, can be applied as a toy model of earthquake supercycles.
October 2017: Chaos
Yang Zhang, Yang Wu, Xiaoxin Wang, Eric R Fossum, Rahul Kumar, Jifeng Liu, Gregory Salamo, Shui-Qing Yu
Searching for innovative approaches to detect single photons remains at the center of science and technology for decades. This paper proposes a zero transit-time, non-avalanche quantum capacitive photodetector to register single photons. In this detector, the absorption of a single photon changes the wave function of a single electron trapped in a quantum dot (QD), leading to a charge density redistribution nearby. This redistribution translates into a voltage signal through capacitive coupling between the QD and the measurement probe...
October 30, 2017: Optics Express
James P Gleeson, Rick Durrett
An avalanche or cascade occurs when one event causes one or more subsequent events, which in turn may cause further events in a chain reaction. Avalanching dynamics are studied in many disciplines, with a recent focus on average avalanche shapes, i.e., the temporal profiles of avalanches of fixed duration. At the critical point of the dynamics, the rescaled average avalanche shapes for different durations collapse onto a single universal curve. We apply Markov branching process theory to derive an equation governing the average avalanche shape for cascade dynamics on networks...
October 31, 2017: Nature Communications
Witold Slówko, Artur Wiatrowski, Michał Krysztof
The paper considers some major problems of adapting the multi-detector method for three-dimensional (3D) imaging of wet bio-medical samples in Variable Pressure/Environmental Scanning Electron Microscope (VP/ESEM). The described method pertains to "single-view techniques", which to create the 3D surface model utilise a sequence of 2D SEM images captured from a single view point (along the electron beam axis) but illuminated from four directions. The basis of the method and requirements resulting from them are given for the detector systems of secondary (SE) and backscattered electrons (BSE), as well as designs of the systems which could work in variable conditions...
October 19, 2017: Micron: the International Research and Review Journal for Microscopy
Giacomo Strapazzon, Daniel Migliaccio, Diego Fontana, Agnieszka Elzbieta Stawinoga, Mario Milani, Hermann Brugger
OBJECTIVE: To explore baseline knowledge about avalanche guidelines and the Avalanche Victim Resuscitation Checklist (AVReCh) in Italy and the knowledge acquisition from a standardized lecture. METHODS: Standardized lecture material discussing AVReCh was presented during 8 mountain medicine courses from November 2014 to April 2016 in different regions of Italy. To determine the knowledge acquisition from the lecture, a pre- and postlecture survey was utilized. RESULTS: A total of 193 surveys were analyzed...
October 23, 2017: Wilderness & Environmental Medicine
Zhijian Li, Jiancheng Lai, Chunyong Wang, Wei Yan, Zhenhua Li
Dead-time has a significant influence on the detection efficiency and range performance of a photon-counting laser radar system with a Geiger-mode avalanche photodiode. In this paper, a rapid universal recursive model of the detection probability of discrete time under various dead-times is proposed, which is verified with controlled parameters. Our model has the advantage of fast computing speed and unifies multi-trigger, single-trigger, and zero-dead-time models. The computing speed is 1 to 2 orders of magnitude faster than Gatt's and Zhao's models under a short dead-time condition, with relative errors less than 0...
August 10, 2017: Applied Optics
Upendra N Singh, Tamer F Refaat, Syed Ismail, Kenneth J Davis, Stephan R Kawa, Robert T Menzies, Mulugeta Petros
Sustained high-quality column carbon dioxide (CO2) atmospheric measurements from space are required to improve estimates of regional and continental-scale sources and sinks of CO2. Modeling of a space-based 2 μm, high pulse energy, triple-pulse, direct detection integrated path differential absorption (IPDA) lidar was conducted to demonstrate CO2 measurement capability and to evaluate random and systematic errors. Parameters based on recent technology developments in the 2 μm laser and state-of-the-art HgCdTe (MCT) electron-initiated avalanche photodiode (e-APD) detection system were incorporated in this model...
August 10, 2017: Applied Optics
Huihua Fu, Ping Wang, Tao Liu, Tian Cao, Lixin Guo, Jiao Qin
The average bit error rate (ABER) performance of an avalanche-photodiode (APD)-based pulse-position modulation (PPM) free-space optical (FSO) communication system is investigated considering the aperture averaging effect. The approximate ABER expression is theoretically derived in terms of M and exponentiated Weibull (EW) distributions under weak-to-strong turbulent atmosphere conditions with a binary PPM (BPPM) scheme. Union-bound and Hermite polynomials are then considered to estimate the performance of M-ary PPM FSO systems...
August 10, 2017: Applied Optics
Arnaud Dumas, Johan Rothman, Fabien Gibert, Dimitri Édouart, Gilles Lasfargues, Claire Cénac, Florian Le Mounier, Jessica Pellegrino, Jean-Paul Zanatta, Alain Bardoux, Francesc Tinto, Pierre Flamant
Benefiting from close to ideal amplification properties (high gain, low dark current, and low excess noise factor), HgCdTe electron initiated avalanche photodiode (e-APD) technology exhibits state of the art sensitivity, thus being especially relevant for applications relying on low light level detection, such as LIDAR (Light Detection And Ranging). In addition, the tunable gap of the Hg1-xCdxTe alloy enables coverage of the short wavelength infrared (SWIR) and especially the 2 μm spectral range. For these two reasons, a HgCdTe e-APD based detector is a promising candidate for future differential absorption LIDAR missions targeting greenhouse gas absorption bands in SWIR...
September 20, 2017: Applied Optics
Hanjun Luo, Zhengbiao Ouyang, Qiang Liu, Zhenli Lu, Bin Li
There exists a performance limitation in a pulsed Geiger-mode avalanche photodiode laser ranging system because of the echo intensity random fluctuation caused by turbulence effects. To suppress the influence of turbulence effects, we present a cumulative pulse detection technique with the ability to achieve improved cumulative probabilities and range accuracy. Based on the modulated Poisson model, the cumulative probabilities, range accuracy, and their influencing factors are investigated for a cumulative Q-switched laser pulse train...
October 10, 2017: Applied Optics
Shaoying Ke, Shaoming Lin, Danfeng Mao, Yujie Ye, Xiaoli Ji, Wei Huang, Cheng Li, Songyan Chen
We investigate the effect of temperature on the single-photon properties of four germanium/silicon (Ge/Si) single-photon avalanche photodiodes (SPADs), which are fabricated by Ge-on-Si direct epitaxial growth, Ge-on-Si two-step epitaxial growth, Ge/Si direct wafer bonding, and Si/Si hydrophobic bonding, respectively. It is found that the wafer-bonded Ge/Si SPAD exhibits extremely low dark current and dark count rate (DCR) compared with the epitaxial ones at 250 and 300 K. This implies that the wafer-bonding technique is a possible candidate for the fabrication of Ge/Si SPAD, which can be operated at near room temperature...
June 1, 2017: Applied Optics
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