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L Rapp, R Meyer, L Furfaro, C Billet, R Giust, F Courvoisier
We develop a novel concept for ultra-high speed cleaving of crystalline materials with femtosecond lasers. Using Bessel beams in single shot, fracture planes can be induced nearly all along the Bessel zone in sapphire. For the first time, we show that only for a pulse duration below 650 fs, a single fracture can be induced in sapphire, while above this duration, cracks appear in all crystallographic orientations. We determine the influential parameters which are polarization direction, crystallographic axes and scanning direction...
April 17, 2017: Optics Express
David R Thompson, Joseph W Boardman, Michael L Eastwood, Robert O Green
The intrinsic spectral dimensionality indicates the observable degrees of freedom in Earth's solar-reflected light field, quantifying the diversity of spectral content accessible by visible and infrared remote sensing. The solar-reflected regime spans the 0.38 - 2.5 μm interval, and is captured by a wide range of current and planned instruments on both airborne and orbital platforms. To date there has been no systematic study of its spectral dimensionality as a function of space, time, and land cover. Here we report a multi-site, multi-year statistical survey by NASA's "Classic" Airborne Visible Near InfraRed Spectrometer (AVIRIS-C)...
April 17, 2017: Optics Express
Tonmoy Chakraborty, Jonathan C Petruccelli
The transport of intensity equation (TIE) is a phase retrieval method that relies on measurements of the intensity of a paraxial field under propagation between two or more closely spaced planes. A limitation of TIE is its susceptibility to low frequency noise artifacts in the reconstructed phase. Under Köhler illumination, when both illumination power and exposure time are limited, the use of larger sources can improve low-frequency performance although it introduces blurring. Appropriately combining intensity measurements taken with a diversity of source sizes can improve both low- and high-frequency performance in phase reconstruction...
April 17, 2017: Optics Express
Guoqiang Xu, Haochun Zhang, Yan Jin, Sen Li, Yao Li
We propose a fundamental latent function of control heat transfer and heat flux density vectors at random positions on thermal materials by applying transformation optics. The expressions for heat flux bending are obtained, and the factors influencing them are investigated in both 2D and 3D cloaking schemes. Under certain conditions, more than one degree of freedom of heat flux bending exists corresponding to the temperature gradients of the 3D domain. The heat flux path can be controlled in random space based on the geometrical azimuths, radial positions, and thermal conductivity ratios of the selected materials...
April 17, 2017: Optics Express
F Mariani, F de León-Pérez, K J A Vendel, L Martín-Moreno, M P Van Exter
We present the first angle resolved measurements of extraordinary optical transmission (EOT) through hole array gratings in a gold film. Varying the lattice spacing of the arrays and looking at higher diffraction orders, we retrieve the angular emission pattern of the constituent holes with better signal to noise ratio than with single-hole experiments. We present a method to determine separately the angular dependence of the direct and resonant contribution to EOT by using the spectral features of the diffraction orders together with an established model...
April 17, 2017: Optics Express
Shaoqi Feng, Chuan Qin, Kuanping Shang, Shibnath Pathak, Weicheng Lai, Binbin Guan, Matthew Clements, Tiehui Su, Guangyao Liu, Hongbo Lu, Ryan P Scott, S J Ben Yoo
This paper demonstrates rapidly reconfigurable, high-fidelity optical arbitrary waveform generation (OAWG) in a heterogeneous photonic integrated circuit (PIC). The heterogeneous PIC combines advantages of high-speed indium phosphide (InP) modulators and low-loss, high-contrast silicon nitride (Si<sub>3</sub>N<sub>4</sub>) arrayed waveguide gratings (AWGs) so that high-fidelity optical waveform syntheses with rapid waveform updates are possible. The generated optical waveforms spanned a 160 GHz spectral bandwidth starting from an optical frequency comb consisting of eight comb lines separated by 20 GHz channel spacing...
April 17, 2017: Optics Express
Benjamin Crooke, Lachlan I W McKinna, Ivona Cetinić
Fowler's Sneaker Depth (FSD), analogous to the well known Secchi disk depth (Zsd), is a visually discerned citizen scientist metric used to assess water clarity in the Patuxent River estuary. In this study, a simple remote sensing algorithm was developed to derive FSD from space-borne spectroradiometric imagery. An empirical model was formed that estimates FSD from red-end remote sensing reflectances at 645 nm, Rrs(645). The model is based on a hyperbolic function relating water clarity to Rrs(645) that was established using radiative transfer modeling and fine tuned using in-water FSD measurements and coincident Rrs(645) data observed by NASA's Moderate Resolution Imaging Spectroradiometer aboard the Aqua spacecraft (MODISA)...
April 17, 2017: Optics Express
Minkyu Sung, Seung-Hyun Cho, Hwan Seok Chung, Sun Me Kim, Jong Hyun Lee
We demonstrate the improvement of the transmission performance based on intermixing noise mitigation techniques in a multiple intermediate-frequency-over-fiber (IFoF) based mobile fronthaul. The interaction between fiber chromatic dispersion and frequency chirp of the directly modulated laser generates the second-order distortion that degrades the performance of multi-IFoF transmission system. To avoid second-order distortion, we use intermediate frequency (IF) spacing optimization and octave-confined frequency plan schemes in which intermixing noise would be generated in the out of signal band and would not affect the quality of transmitted signal...
April 17, 2017: Optics Express
Yacov Y Haimes
The emergence of the complexity characterizing our systems of systems (SoS) requires a reevaluation of the way we model, assess, manage, communicate, and analyze the risk thereto. Current models for risk analysis of emergent complex SoS are insufficient because too often they rely on the same risk functions and models used for single systems. These models commonly fail to incorporate the complexity derived from the networks of interdependencies and interconnectedness (I-I) characterizing SoS. There is a need to reevaluate currently practiced risk analysis to respond to this reality by examining, and thus comprehending, what makes emergent SoS complex...
April 24, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
Panqu Wang, Garrison W Cottrell
What are the roles of central and peripheral vision in human scene recognition? Larson and Loschky (2009) showed that peripheral vision contributes more than central vision in obtaining maximum scene recognition accuracy. However, central vision is more efficient for scene recognition than peripheral, based on the amount of visual area needed for accurate recognition. In this study, we model and explain the results of Larson and Loschky (2009) using a neurocomputational modeling approach. We show that the advantage of peripheral vision in scene recognition, as well as the efficiency advantage for central vision, can be replicated using state-of-the-art deep neural network models...
April 1, 2017: Journal of Vision
Mireia Ercilla-Montserrat, Rebeca Izquierdo, Jordina Belmonte, Juan Ignacio Montero, Pere Muñoz, Concepción De Linares, Joan Rieradevall
Building-integrated rooftop greenhouse (i-RTG) agriculture has intensified in recent years, due to the growing interest in the development of new agricultural spaces and in the promotion of food self-sufficiency in urban areas. This paper provides a first assessment of the indoor dynamics of bioaerosols in an i-RTG, with the aim of evaluating biological air quality in a tomato greenhouse near Barcelona. It evaluates the greenhouse workers' exposure to airborne pollen and fungal spores in order to prevent allergy problems associated with occupational tasks...
April 21, 2017: Science of the Total Environment
Yang Liu, Wen-Ming Jiang, Jie Yang, Yu-Xing Li, Ming-Can Chen, Jian-Na Li
Tilt angle of parallel-plate electrodes (APE) is very important as it improves the economy of diffusion controlled Electrocoagulation (EC) processes. This study aimed to evaluate and optimize APE of a self-made EC device including integrally rotary electrodes, at a fixed current density of 120 Am(-2). The APEs investigated in this study were selected at 0°, 30°, 45°, 60°, 90°, and a special value (α(d)) which was defined as a special orientation of electrode when the upper end of anode and the lower end of cathode is in a line vertical to the bottom of reactor...
April 12, 2017: Chemosphere
Li Kuo Tan, Yih Miin Liew, Einly Lim, Robert A McLaughlin
Automated left ventricular (LV) segmentation is crucial for efficient quantification of cardiac function and morphology to aid subsequent management of cardiac pathologies. In this paper, we parameterize the complete (all short axis slices and phases) LV segmentation task in terms of the radial distances between the LV centerpoint and the endo- and epicardial contours in polar space. We then utilize convolutional neural network regression to infer these parameters. Utilizing parameter regression, as opposed to conventional pixel classification, allows the network to inherently reflect domain-specific physical constraints...
April 12, 2017: Medical Image Analysis
Shinhyun Choi, Jong Hoon Shin, Jihang Lee, Patrick Sheridan, Wei D Lu
Memristors have been considered as a leading candidate for a number of critical applications ranging from non-volatile memory to non-Von Neumann computing systems. Feature extraction, which aims to transform input data from a high dimensional space to a space with fewer dimensions, is an important technique widely used in machine learning and pattern recognition applications. Here, we experimentally demonstrate that memristor arrays can be used to perform principal component analysis (PCA), one of the most commonly-used feature extraction techniques, through online, unsupervised learning...
April 24, 2017: Nano Letters
Michael D Aleo, Falgun Shah, Kan He, Paul D Bonin, A David Rodrigues
The role of bile salt export protein (BSEP) inhibition in drug-induced liver injury (DILI) has been investigated widely, while inhibition of the canalicular multidrug resistant protein 3 (MDR3) has received less attention. This transporter plays a pivotal role in secretion of phospholipids into bile and functions coordinately with BSEP to mediate the formation of bile acid-containing biliary micelles. Therefore, inhibition of MDR3 in human hepatocytes was examined across 125 drugs (70 of Most- and 55 of No-DILI-concern)...
April 24, 2017: Chemical Research in Toxicology
Cuiping Ma, Chao Liang, Yifan Wang, Mei Pan, Qianqian Jiang, Chao Shi
Combinatorial approaches in directed evolution were proven to be more efficient for exploring sequence space and innovating the function of protein. We presented modular assembly of secondary structures (MASS) for constructing a combinatorial library. In this approach, secondary structure elements were extracted from natural existing proteins, the common linkers were flanking secondary structure elements, then digested by Hinf I restriction endonuclease that was used in the construction of combinatorial library for the first time...
April 24, 2017: ACS Combinatorial Science
C Ross Schmidtlein, Yizun Lin, Si Li, Andrzej Krol, Bradley J Beattie, John L Humm, Yuesheng Xu
PURPOSE: Performance of the preconditioned alternating projection algorithm (PAPA) using relaxed ordered subsets (ROS) with a non-smooth penalty function was investigated in positron emission tomography (PET). A higher order total variation (HOTV) regularizer was applied and a method for unsupervised selection of penalty weights based on the measured data is introduced. METHODS: A ROS version of PAPA with HOTV penalty (ROS-HOTV-PAPA) for PET image reconstruction was developed and implemented...
April 24, 2017: Medical Physics
E R Kluge, M C Mendes, M V Faria, H O Santos, L A Santos, I E Sandini
In this study, we evaluated the fungicide effect on the incidence of rot grains and expression of catalase (CAT), alcohol dehydrogenase (ADH), and malate dehydrogenase (MDH) enzymes in commercial maize hybrids grown with conventional and reduced spacing in Guarapuava, PR, Brazil. The experiment was designed in random blocks with a 3 × 8-factorial scheme, totaling 24 treatments. The first factor constituted three levels, the first with foliar fungicide application [150.0 g/L trifloxystrobin (15.0%, w/v) + 175...
April 20, 2017: Genetics and Molecular Research: GMR
Yunpeng Cai, Wei Zheng, Jin Yao, Yujie Yang, Volker Mai, Qi Mao, Yijun Sun
The rapid development of sequencing technology has led to an explosive accumulation of genomic sequence data. Clustering is often the first step to perform in sequence analy- sis, and hierarchical clustering is one of the most commonly used approaches for this purpose. However, it is currently computationally expensive to perform hierarchical clustering of extremely large sequence datasets due to its quadratic time and space complexities. In this paper we developed a new algorithm called ESPRIT-Forest for parallel hierarchical clustering of sequences...
April 24, 2017: PLoS Computational Biology
W M Cheung, K S Chan
We study the Floquet quasi-energy band structure of bilayer graphene when it is illuminated by two laser lights with frequencies [Formula: see text] and [Formula: see text] using Floquet theory. We focus on the dynamical gap formed by the conduction band with Floquet index  =  -1 and the valence band with Floquet index  =  +1 to understand how Dirac points can be formed. It is found that the dynamical gap does not have rotation symmetry in the momentum space, and quasi-Dirac points, where the conduction and valence bands almost touch, can be created when the dynamical gap closes along some directions with suitably chosen radiation parameters...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
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