bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrically Tunable Optical Metasurfaces with Barium Titanate Nanoparticles
Authors: Richter Felix U. , Vogler-Neuling Viola V. , Timpu Flavia , Karvounis Artemios , Pohl David , Weigand Helena C. , Escalé Marc Reig , Grange Rachel
Published: September 2020

We demonstrate electrical tuning of optical metasurfaces realized in barium titanate nanoparticle thin-films. An electrically induced linear resonance shift of (1.6 ± 1.2) nm/V has been observed in the metasurfaces transmission spectra.
Demonstration of 8-Step Single-Photon Quantum Walk using 32 x 32 Reconfigurable Silicon Photonics Switch
Authors: Konoike Ryotaro , Yoshizawa Akio , Namiki Shu , Ikeda Kazuhiro
Published: September 2020

We implemented a reconfigurable quantum-walk circuit on a 32*32 silicon photonics switch system. The 1 to 8-step quantum walk exhibited a long-term stability over 45 hours with clear single-photon interference for 10-nm-bandwidth heralded single photons.
Topological protection of biphoton states generated in waveguide arrays by parametric fluorescence
Authors: Bergamasco Nicola , Liscidini Marco
Published: September 2020

We study spontaneous four-wave mixing in waveguide arrays supporting topologically protected modes. We clarify the mechanisms associated with the topological pro-tection of the quantum correlations of the generated photon pairs.
A General Framework for Nanoscale Electromagnetism
Authors: Yang Yi , Zhu Di , Yan Wei , Agrawal Akshay , Zheng Mengjie , Joannopoulos John D. , Lalanne Philippe , Christensen Thomas , Berggren Karl , Soljačić Marin
Published: September 2020

We introduce the mesoscopic electromagnetic boundary conditions and establish an experimental procedure to measure the dispersive surface response functions, enabled by observations of pronounced nonclassical effects—spectral shifts >30% and the breakdown of Kreibig-like broadening.
Maximal Concentration of Electromagnetic Waves
Authors: Shim Hyungki , Chung Haejun , Miller Owen D.
Published: September 2020

We derive general bounds to optical superresolution, i.e., maximum intensity for electromagnetic waves from arbitrary wavefront-shaping devices that break the diffraction “limit.” We use inverse design to discover metasurfaces operating close to our bounds.
The Nanophotonic Dialogue between Antennas and Molecules
Authors: van Hulst Niek F.
Published: September 2020

I will present both deterministic scanning antenna and stochastic localisation mapping of the nanoscale antenna-molecule interaction, towards stronger coupling, bright single photon sources, rate enhancement and spectral control.
A Pragmatic Metasurface with Asymmetric Spin Interactions
Authors: Naveed Muhammad Ashar , Ansari Muhammad Afnan , Kim Inki , Zubair Muhammad , Riaz Kashif , Tauqeer Tauseef , Rho Junsuk , Mehmood Muhammad Qasim
Published: September 2020

Traditional PB-Phase metaholograms based on spin-orbit-interactions exhibit central- symmetric holographic images, applying a limit to the helicity-multiplexing. Asymmetric metasurface is proposed to achieve spin-dependent and bidirectional propagation with high conversion efficiency and fidelity.
Optically-induced antiferromagnetic order in Mie-resonant dielectric metasurfaces
Authors: Zhou Wenjia , Choi Duk-Yong , Sautter Jurgen , Arslan Dennis , Zou Chengjun , Fasold Stefan , Lepeshov Sergey , Pertsch Thomas , Staude Isabelle , Kivshar Yuri
Published: September 2020

We study silicon-based metasurfaces with complex unit cells composed of Mieresonant dielectric nanodisks and nanorings and observe experimentally a signature of optical response with a staggered structure of optically-induced magnetic dipole moments, associated with the so-called optical antiferromagnetic order.
Octave bandwidth Metasurface lens
Authors: Ndao A. , Hsu L.-Y. , Ha J. , Park J. , Chang-Hasnain C. , Kante B.
Published: September 2020

We report and experimentally demonstrate polarization-independent fishnet- achromatic-metalenses with measured average efficiencies over 70% in the continuous band from the visible (640 nm) to the infrared (1200 nm).
Emitter-Metasurface Interface for Manipulating Emission Characteristics of Quantum Defects
Authors: Jha Pankaj K. , Shirmanesh Ghazaleh K. , Akbari Hamidreza , Grajower Meir Y. , Parazzoli Claudio G. , Koltenbah Benjamin E. C. , Atwater Harry A.
Published: September 2020

We demonstrate a chip-scale quantum emitter-metamaterial device that emits highly directional photons. Our device opens the door for quantum imaging of yveak sources by adding photon(s) to manipulate the photon statistics for improved signal-to-noise ratio.
Enhancing the performance of coupled cavity-antenna plasmonic nanostructures for ultrafast quantum photonics
Authors: Bogdanov Simeon I. , Makarova Oksana A. , Xu Xiaohui , Lagutchev Alexei S. , Shah Deesha , Gabidullin Aidar R. , Ryzhikov Ilya A. , Rodionov Ilya A. , Kildishev Alexander V. , Bozhevolnyi Sergey I. , Boltasseva Alexandra , Shalaev Vladimir M. , Khurgin Jacob B.
Published: September 2020

We analytically establish the fundamental limit for quantum emission enhancement in plasmonic nanostructures combining smaller (cavity) and larger (antenna) modes. We confirm this result numerically and optimize the performance of nanoantennas experimentally through controlled photomodification.
Merging Machine Learning with Quantum Photonics: Rapid classification of quantum sources
Authors: Kudyshev Zhaxylyk , Bogdanov Simeon , Isacsson Theodor , Kildishev Alexander V. , Boltasseva Alexandra , Shalaev Vladimir M.
Published: September 2020

Single quantum emitters offer useful functionalities for quantum optics, but measurements of their properties are time-consuming. We demonstrate that machine learning dramatically reduces data collection time (1s), increasing the accuracy of second-order autocorrelation measurements (>90%).
Dissipative Kerr solitons in a photonic dimer
Authors: Tikan A. , Riemensberger J. , Komagata K. , Honl S. , Churaev M. , Skehan C. , Guo H. , Wang R. N. , Liu J. , Seidler P. , Kippenberg T. J.
Published: September 2020

We study nonlinear dynamics emerging in a photonic microring dimer. It is shown that four wave mixing pathways between the dimer supermodes lead to novel nonlinear phenomena going beyond the single resonator physics.
Room-Temperature Lasing Action from All-dielectric Metasurfaces Near Bound States in the Continuum
Authors: Azzam S. I. , Chaudhuri K. , Lagutchev A. , Kim Y. L. , Shalaev V. M. , Boltasseva A. , Kildishev A. V.
Published: September 2020

We demonstrate lasing action in the visible from an all-dielectric metasurface. A low laser threshold is achieved with a high-Q resonance due to operation at the near bound states in the continuum (BIC) regime.
Thermodynamic pressure emerging from highly multimoded nonlinear optical systems
Authors: Ren Huizhong , Wu Fan O. , Jung Pawel , Khajavikhan Mercedeh , Christodoulides Demetrios N.
Published: September 2020

We demonstrate that in nonlinear waveguide arrangements, the optical thermodynamic pressure results from the electrodynamic force exerted on the guiding interface and from an entropy growth term associated with an irreversible expansion.
Ultrafast carrier dynamics in the candidate magnetic Weyl semimetal EuCd2As2
Authors: O’Neal Kenneth R. , Mix LaMoyne T. , Lee Min-Cheol , Kuthanazhi Brinda , Jo Na H. , Bud’ko Sergey , Canfield Paul , Prasankumar Rohit P. , Yarotski Dmitry A.
Published: September 2020

Ultrafast optical pulses were used to search for light-induced topological changes in the candidate magnetic Weyl semimetal EuCd2As2, revealing signatures of coupling between spin and charge degrees of freedom which holds promise for device applications.
Control and Optimization of High Harmonic Generation in 3D Dirac Semimetals
Authors: Lim Jeremy , Ang Yee Sin , de Abajo Francisco Javier Garcia , Kaminer Ido , Ang Ricky , Wong Liang Jie
Published: September 2020

We show that 3D Dirac semimetals (DSMs) can function as efficient emitters of high- harmonic radiation and identify operation regimes for controlled and suppressed high-order light emission.
Acousto-Optics in Lithium Niobate-on-Sapphire
Authors: Sarabalis Christopher J. , McKenna Timothy P. , Patel Rishi N. , Safavi-Naeini Amir H.
Published: September 2020

We demonstrate nanophotonic waveguides modulated by surface acoustic waves and use them to study the piezoelectric and photoelastic properties of thin-film lithium niobate-on-sapphire.
Demonstration of High Quantum Cooperativities and Optomechanical Strong Coupling within a Bulk Crystalline Cavity Optomechanical System
Authors: Kharel Prashanta , Chu Yiwen , Kittlaus Eric A. , Otterstrom Nils T. , Gertler Shai , Mason David , Rakich Peter T.
Published: September 2020

Within a Brillouin-based bulk crystalline cavity optomechanical system, we demonstrate high quantum cooperativities as well as strong coupling between infrared light and high-frequency (12.7 GHz) bulk acoustic modes.
Resonant dissipative Kerr soliton supercontinuum in the normal dispersion regime
Authors: Anderson Miles , Lihachev Grigory , Liu Junqiu , Herr Tobias , Kippenberg Tobias J.
Published: September 2020

We demonstrate broadband resonant supercontinuum generation in a Si3N4 microresonator with normal dispersion. Rectangular bright pulses are shown to form directly using synchronous pulse-driving, generating a 2,600-line comb at 28 GHz repetition rate.
Multistability-Enabled Complex Soliton Dynamics in a Bichromatically Driven Optical Microresonator
Authors: Weng Wenle , Bouchand Romain , Kippenberg Tobias J.
Published: September 2020

We enter a bichromatically-pumped multistability regime in a microresonator to observe the emergence of complex dynamics of dissipative Kerr soliton interactions, including short-range soliton binding and periodic soliton collision.
Dynamically Tunable Amplitude and Phase Modulation Using Vanadium Dioxide Huygens Metasurfaces
Authors: Oguntoye Isaac O. , Ollanik Adam J. , Padmanabha Siddharth , Hartfield George Z. , Simone Brittany K. , Escarra Matthew D.
Published: September 2020

We design and fabricate continuously tunable vanadium dioxide Huygens metasurfaces for optical modulation in an all-in-one device. Simulation results show near π continuous phase modulation and ~20 dB amplitude modulation at near infrared wavelengths. Experimental verification is in progress.
Reconfigurable photonic structures for solving linear differential equations
Authors: Tzarouchis Dimitrios C. , Engheta Nader
Published: September 2020

We theoretically explore a reconfigurable, Mach—Zehnder interferometer-based photonic network capable of solving linear equations by implementing arbitrary matrix operators. The solutions of various differential equations are numerically demonstrated and discussed.
Longitudinally Variable Polarization Optics
Authors: Dorrah Ahmed H. , Rubin Noah A. , Zaidi Aun , Tamagnone Michele , Capasso Federico
Published: September 2020

We introduce a new class of polarizing elements (analyzers and retarders) that virtually rotate their orientation as a function of the propagation distance, thus expanding the scope of conventional polarization devices into 3D space.
Monolayer lasing from photoactivation-enhanced photoluminescence at room temperature
Authors: Gu Fuxing
Published: September 2020

We use a photoactivation method to enhance the room-temperature photoluminescence quantum yields in monolayer MoS2 grown on silica micro/nanofibres by more than two orders of magnitude, and realize continuous-wave lasing with greatly reduced thresholds.
Negative Extinction and Broadband Light-matter Interactions in High-Q Time-variant Metasurfaces
Authors: Shcherbakov Maxim R. , Lemasters Robert , Song Jia , Shafirin Pavel , Lian Tianquan , Harutyunyan Hayk , Shvets Gennady
Published: September 2020

We present experimental observations of frequency conversion and negative optical extinction in time-variant metasurfaces and their applications to surpassing the time-bandwidth limit in photonics.
Breaking Reciprocity with Space-Time Phase Modulated Metasurfaces
Authors: Guo Xuexue , Ding Yimin , Duan Yao , Ni Xingjie
Published: September 2020

We constructed a space-time phase modulated metasurface consisting of amorphous silicon building blocks, and demonstrated nonreciprocal light reflection at wavelengths around 860 nm. Our approach paves a way for miniaturized on-chip nonreciprocal optical components.
Exceptional Point Based He-Ne Ring Laser Gyroscope
Authors: Hokmabadi Mohammad P. , Schumer Alexander , Christodouides Demetrios N. , Khajavikhan Mercedeh
Published: September 2020

A non-Hermitian He-Ne ring laser gyroscope (RLG) that operates at an exceptional point is proposed and experimentally realized. Compared to a standard RLG, the device exhibits more than an order of magnitude enhancement in sensitivity.
Site-controlled generation of tin-vacancy centers in diamond via shallow ion implantation and diamond overgrowth
Authors: Rugar Alison E. , Lu Haiyu , Dory Constantin , Sun Shuo , McQuade Patrick J. , Shen Zhi-Xun , Melosh Nicholas A. , Vuckovic Jelena
Published: September 2020

We generate tin-vacancy (SnV-) centers in patterned arrays by shallowly implanting Sn ions into diamond through an implantation mask and subsequently growing diamond. This method eliminates extraneous emission lines present in vacuum-annealed SnV- samples.
High-Gain Twin-Beam Generation in Waveguides: Experimental Characterization Using Cascaded Stimulated Emission
Authors: Vidrighin Mihai D. , Triginer Gil , Quesada Nicolás , Eckstein Andreas , Moore Merritt , Kolthammer W. Steven , Sipe J. E. , Walmsley Ian A.
Published: September 2020

We introduce a new method for spectral characterization of twin-beam generation in waveguides, based on cascaded stimulated emission. We provide a complete and accurate experimental characterization of high-gain effects in a parametric down-conversion source.
One Dimensional Long Range Surface Plasmon Polariton Topological Insulator in Telecomm Wavelength
Authors: Gladstone Ran Gladstein , Shvets Gennady
Published: September 2020

We present a platform that implements the topological Su-Schrieffer-Heeger model using long range surface plasmon polaritons on a gold strip at telecomm wavelength. We provide a theoretical model and simulations showing a topological edge mode.
Demonstration of highly unidirectional edge states in terahertz slab waveguides
Authors: Xiong Hao , Lu Yao , Wu Qiang , Xu Jingjun
Published: September 2020

We achieved highly unidirectional topological edge states in a terahertz slab waveguide based on the triangular honeycomb lattice. The unidirectional property and robustness of edge states against various kinds of defects were presented and studied.
Incoherent Branched Flow of Light
Authors: Patsyk Anatoly , Sivan Uri , Segev Mordechai
Published: September 2020

We present the first observation of optical branched flow of spatially-incoherent light.
TM Polarized Photon Pair Generation in Linearly Uncoupled Silicon Resonators
Authors: Starling David J. , Poirier Jacob , Fanto Michael , Steidle Jeffrey A. , Tison Christopher C. , Howland Gregory A. , Preble Stefan F.
Published: September 2020

We demonstrate photon pair production with measured rates above 1 kHz in linearly uncoupled resonators in a silicon waveguide using highly dispersive TM polarized light. This approach extends the capabilities of quantum devices in silicon.
Cavity Quantum Electrodynamical Metamaterials
Authors: Yu Josephine , Sloan Jamison , Rivera Nicholas , Soljačić Marin
Published: September 2020

We introduce the concept of designing new optical materials from “meta-atoms” comprised of matter ultra-strongly-coupled to an optical cavity. Such “strongly-coupled” materials can have surprising properties, such as metallic behavior at low frequencies.
Generation of Topological Space-Time Non-Separable Light Pulses
Authors: Zdagkas Apostolos , Hou Yaonan , Savinov Vassili , Zhang Huifang , Buchnev Oleksandr , Papasimakis Nikitas , Zheludev Nikolay I.
Published: September 2020

We report the generation of space-time non-separable toroidal pulses of complex topological structure. Such pulses, a formation of singularities propagating in free space, are ideal probes for toroidal and anapole modes in matter.
Experimental observation of braiding topological zero modes in a photonic waveguide array
Authors: Noh Jiho , Schuster Thomas , Iadecola Thomas , Huang Sheng , Wang Mohan , Chen Kevin P. , Chamon Claudio , Rechtsman Mikael C.
Published: September 2020

We demonstrate a non-trivial Berry phase that originates from braiding topological defects in a photonic waveguide array. The non-zero Berry phase implies that braiding operations involving the defects are non-Abelian.
The non-Hermitian Skin Effect as Light Funnel
Authors: Kremer Mark , Weidemann Sebastian , Helbig Tobias , Hofmann Tobias , Stegmaier Alexander , Greiter Martin , Thomale Ronny , Szameit Alexander
Published: September 2020

Non-Hermiticity, induced by anisotropic coupling, makes the mode spectrum highly sensitive to the existence of boundaries. We demonstrate and exploit this behaviour experimentally in a photonic lattice to construct a light funnel.
Array-scale inverse design of active metasurfaces
Authors: Thureja Prachi , Shirmanesh Ghazaleh Kafaie , Fountaine Katherine T. , Sokhoyan Ruzan , Grajower Meir , Atwater Harry A.
Published: September 2020

We develop an inverse design approach to optimize array architectures of reconfigurable metasurfaces and report dramatically improved beam steering performances with non-ideal antenna components. The versatility is enhanced by enabling continuous steering up to 70°.
Optical Fourier Surfaces
Authors: Norris David J.
Published: September 2020

Complex “wavy” surfaces cannot be easily fabricated, frustrating the design and implementation of sophisticated diffractive optics. We will discuss a simple but powerful approach that provides surfaces containing an arbitrary number of specified spatial frequencies.
Coherent scattering from quantum dots: beyond the atomic picture
Authors: Brash Alistair J. , Iles-Smith Jake , Phillips Catherine L. , O’Hara John , Royall Benjamin , Wilson Luke R. , Skolnick Maurice S. , Fox A. Mark , McCutcheon Dara P. S. , Clarke Edmund , Mørk Jesper , Nazir Ahsan
Published: September 2020

Coherent scattering by a quantum dot in a nano-cavity with high Purcell factor is demonsttated. Major deviations from atom-like behaviour are observed due to phonon coupling that is completely insensitive to excitation conditions.
Observation of non-contractible loop states in a photonic Kagome lattice of Corbino-geometry
Authors: Ma Jina , Rhim Jun-Won , Tang Liqin , Xia Shiqi , Wang Haiping , Zheng Xiuyan , Xia Shiqiang , Song Daohong , Hu Yi , Li Yigang , Yang Bohm-Jung , Leykam Daniel , Chen Zhigang
Published: September 2020

We demonstrate robust-boundary-mode (RBM) and non-contractible loop state (NLS) in a photonic Kagome lattice, manifesting unique topological entities in flatband systems. We achieve direct observation of the NLS along toroidal direction in a Corbino- geometry.
Demonstration of nonlinearity-induced coupling to topological edge and interface states
Authors: Xia Shiqi , Wang Nan , Smirnova Daria , Smirnov Lev , Tang Liqin , Song Daohong , Szameit Alexander , Leykam Daniel , Chen Zhigang
Published: September 2020

We observe nonlinearity-induced excitation of topological edge and interface states in a photonic SSH lattice, where two beams from opposite directions are coupled into (reflected from) nontrivial defect channel under nonlinear (linear) excitation upon collision.
Recurrent Machine Learning and Computing with Nonlinear Optical Waves
Authors: Williamson Ian A. D. , Hughes Tyler W. , Minkov Momchil , Fan Shanhui
Published: September 2020

We demonstrate that optical time-dynamics are equivalent to a recurrent neural network and that they can be trained for high-performance on complex classification tasks, paving the way for passive analog machine learning processors.
Simultaneous analog computing using multi-frequency inverse-designed metamaterial platforms
Authors: Camacho Miguel , Edwards Brian , Engheta Nader
Published: September 2020

Here we introduce inverse-designed structures for inverting several matrices at the same time by exploiting multi-frequency design. We demonstrate possibilities of feasible designs for up to four different mathematical kernels that can be inverted simultaneously.
Demonstration of an Atomic Frequency Comb Quantum Memory Using Velocity-Selective Pumping in Warm Alkali Vapour
Authors: Hird T. M. , Main D. J. , Gao S. , Oguz E. , Saunders D. J. , Walmsley I. A. , Ledingham P. M.
Published: September 2020

We present the first demonstration of velocity-selective pumping in an atomic vapour to preserve light-matter coherence. Control is illustrated by a subsequent demonstration of an atomic frequency comb quantum memory realised in the vapour.
Erbium-ytterbium co-doped aluminium oxide waveguide amplifiers fabricated by reactive co-sputtering and wet chemical etching
Authors: Bonneville Dawson B. , Frankis Henry C. , Wang Renjie , Bradley Jonathan D. B.
Published: September 2020

We report on the fabrication and optical characterization of erbium-ytterbium co-doped aluminum oxide (Al2O3:Er3+:Yb3+) waveguides using low-cost, low-temperature deposition and etching steps. We deposited Al2O3:Er3+:Yb3+ films using reactive co-sputtering, with Er3+ and Yb3+ ion concentrations ranging from 1.4–1.6 × 1020 and 0.9–2.1 × 1020 ions/cm3, respectively. We etched ridge waveguides in 85% pure phosphoric acid at 60°C, allowing for structures with minimal polarization sensitivity and acceptable bend radius suitable for optical amplifiers and avoiding alternative etching chemistries which use hazardous gases. Scanning-electron-microscopy (SEM) and profilometry were used to assess the etch depth, sidewall roughness, and facet profile of the waveguides. The Al2O3:Er3+:Yb3+ films exhibit a background loss as low as 0.2 ± 0.1 dB/cm and the waveguide loss after structuring is determined to be 0.5 ± 0.3 dB/cm at 1640 nm. Internal net gain of 4.3 ± 0.9 dB is demonstrated at 1533 nm for a 3.0 cm long waveguide when pumped at 970 nm. The material system is promising moving forward for compact Er-Yb co-doped waveguide amplifiers and lasers on a low-cost silicon wafer-scale platform.
Volumetric chemical imaging in vivo by a remote-focusing stimulated Raman scattering microscope
Authors: Lin Peng , Ni Hongli , Li Huate , Vickers Nicholas A. , Tan Yuying , Gong Ruyi , Bifano Thomas , Cheng Ji-Xin
Published: September 2020

Operable under ambient light and providing chemical selectivity, stimulated Raman scattering (SRS) microscopy opens a new window for imaging molecular events on a human subject, such as filtration of topical drugs through the skin. A typical approach for volumetric SRS imaging is through piezo scanning of an objective lens, which often disturbs the sample and offers a low axial scan rate. To address these challenges, we have developed a deformable mirror-based remote-focusing SRS microscope, which not only enables high-quality volumetric chemical imaging without mechanical scanning of the objective but also corrects the system aberrations simultaneously. Using the remote-focusing SRS microscope, we performed volumetric chemical imaging of living cells and captured in real time the dynamic diffusion of topical chemicals into human sweat pores.
Hybrid autofluorescence and photoacoustic label-free microscopy for the investigation and identification of malignancies in ocular biopsies
Authors: Tserevelakis George J. , Mavrakis Kostas G. , Pantazopoulou Danai , Lagoudaki Eleni , Detorakis Efstathios , Zacharakis Giannis
Published: September 2020

We demonstrate the development and application of a prototype hybrid microscopy system integrating autofluorescence (AF) and photoacoustic (PA) label-free contrast modes, for the differentiation of ocular tumors in human surgical biopsies. Hybrid imaging was performed in conjunctival nevi and uveal melanomas tissue sections to acquire quantified data for each molecular background. The AF and PA signals were spatially correlated to establish a novel malignancy indicator that could detect melanomas with high accuracy (t-test;

p
<

0.01

). The proposed methodology has the potential to simplify relevant diagnostic procedures and paves the way for the development of novel ophthalmoscopes aiming to the early diagnosis of ocular malignancies in a clinical setting.
Photonic compressive sensing of sparse radio frequency signals with a single dual-electrode Mach–Zehnder modulator
Authors: Yang Bo , Yang Shuna , Cao Zizheng , Ou Jun , Zhai Yanrong , Chi Hao
Published: September 2020

A novel approach to realizing compressive sensing (CS) of sparse radio frequency (RF) signals based on photonic random demodulation (RD) is proposed. The key function of mixing the RF signal under test and the bipolar pseudo-random binary sequence (PRBS) in photonic RD is implemented with a single dual-electrode Mach–Zehnder modulator (DEMZM). By properly setting the DC bias of the DEMZM at

V
π

and the voltages of the PRBS at

±

V
π

/

2

, a pure desired multiplication term between the signal and the bipolar PRBS is obtained after an AC-coupled photodetector (PD), which not only simplifies the modeling of the CS link but also improves the recovery performance. A proof-of-concept experiment is demonstrated where a sparse signal with spectral components of 500 MHz and 950 MHz is successfully identified with a compression ratio of 20. Simulation results are also given to show the advantage of the given photonic CS scheme with bipolar random mixing.
Measuring functional brain recovery in regenerating planarians by assessing the behavioral response to the cholinergic compound cytisine
Authors: Pagán Oné R. , Baker Debra L. , Deats Sean , O’Brien Mary , Dymond Rochelle , DeMichele Gabriella
Published: September 2020

Planarians are traditional model invertebrates in regeneration and developmental biology research that also display a variety of quantifiable behaviors useful to screen for pharmacologically active compounds. One such behavior is the expression of seizure-like movements (pSLMs) induced by a variety of substances. Previous work from our laboratory showed that cocaine, but not nicotine, induced pSLMs in intact but not decapitated planarians. Interestingly, as decapitated planarians regenerated their heads, they gradually recovered their sensitivity to cocaine. These results suggested a method to assess planarian brain regeneration and a possible way of identifying compounds that could enhance or hold back brain regeneration. In the present work, we demonstrate that the cholinergic agent cytisine is a suitable reference compound to apply our method. Cytisine induces pSLMs in a concentration-dependent manner in intact (but not decapitated) planarians of the species Girardia tigrina. Based on our data, we developed a behavioral protocol to assess planarian brain regeneration over time. We tested this method to measure the effect of ethanol on G. tigrina’s brain regeneration. We found that ethanol slows down the rate of planarian brain regeneration in a concentration-dependent manner, consistently with data from other research groups that tested ethanol effects on planarian brain regeneration using different behavioral protocols. Thus, here we establish a general method using cytisine-induced pSLMs as an indicator of brain regeneration in planarians, a method that shows potential for assessing the effect of pharmacologically active compounds in this process.
Unceasingly searching for answers - an interview with Claudio Stern
Authors: Sanchez-Alvarado Alejandro
Published: September 2020

Claudio Stern was born in Montevideo, Uruguay where he received his school education. He moved to the United Kingdom at age 18. This interview briefly explores his trajectory from Uruguay, through universities in the UK (Sussex, UCL, Cambridge and Oxford) and USA (Columbia) and how he was influenced by various mentors and experiences.
Anatomical and genetic bases underlying the convergent evolution of fleshy and dry dehiscent fruits in Cestrum and Brugmansia (Solanaceae)
Authors: Hernández-Ciro Natalí , Pabón-Mora Natalia
Published: September 2020

The mechanisms controlling evolutionary shifts between dry and fleshy fruits in angiosperms are poorly understood. In Solanaceae, Cestrum and Brugmansia represent cases of convergent evolution of fleshy and dry fruits, respectively. Here we study the anatomical and genetic bases of the independent origin of fleshy fruits in Cestrum and the reversion to dry dehiscent fruits in Brugmansia. We also characterize the expression of candidate fruit development genes, including ALCATRAZ/SPATULA, FRUITFULL, HECATE1/2/3, REPLUMLESS and SHATTERPROOF. We identify anatomical changes to establish developmental stages in the ovary-to-fruit transition in Cestrum nocturnum and Brugmansia suaveolens. We generate reference transcriptomes for both species, isolate homologs for all genes in the fruit genetic regulatory network (GRN) and perform gene expression analyses for ALC/SPT, FUL, HEC1/2/3, RPL and SHP throughout fruit development. Finally, we compare our results to expression patterns found in typical capsules of Nicotiana tabacum and berries of Solanum lycopersicum available in public repositories. We have identified homologous, homoplasious and unique anatomical features in C. nocturnum and B. suaveolens fruits, resulting in their final appearance. Expression patterns suggest that FUL, SHP and SPT might control homologous characteristics, while ALC and RPL likely contribute to homoplasious anatomical features. The fruit GRN changes considerably in these genera when compared to typical capsules and berries of Solanaceae, particularly in B. suaveolens, where expression of FUL2 and RPL1 is lacking.
Roles of cytochromes P450 in plant reproductive development
Authors: Distéfano Ayelén M. , Setzes Nicolás , Cascallares Milagros , Fiol Diego F. , Zabaleta Eduardo , Pagnussat Gabriela C.
Published: September 2020

The cytochrome P450 superfamily is a large enzymatic protein family that is widely distributed along diverse kingdoms. In plants, cytochrome P450 monooxygenases (CYPs) participate in a vast array of pathways leading to the synthesis and modification of multiple metabolites with variable and important functions during different stages of plant development. This includes the biosynthesis and degradation of a great assortment of compounds implicated in a variety of physiological responses, such as signaling and defense, organ patterning and the biosynthesis of structural polymers, among others. In this review, we summarize the characteristics of the different families of plant CYPs, focusing on the most recent advances in elucidating the roles of CYPs in plant growth and development and more specifically, during plant gametogenesis, fertilization and embryogenesis.
Photoreceptor progenitor dynamics in the zebrafish embryo retina and its modulation by primary cilia and N-cadherin
Authors: Aparicio Gonzalo , Rodao Magela , Badano José L. , Zolessi Flavio R.
Published: September 2020

Photoreceptor cells of the vertebrate neural retina originate in the neuroepithelium, and like other neurons, must undergo cell body translocation and polarity transitions to acquire their final functional morphology, which includes features of neuronal and epithelial cells. We analyzed this process in detail in zebrafish embryos using in vivo confocal microscopy and electron microscopy. Photoreceptor progenitors were labeled by the transgenic expression of enhanced green fluorescent protein under the regulation of the photoreceptor-specific promoter crx, and structures of interest were disrupted using morpholino oligomers to knock-down specific genes. Photoreceptor progenitors detached from the basal retina at pre-mitotic stages, rapidly retracting a short basal process as the cell body translocated apically. They remained at an apical position indefinitely to form the outer nuclear layer (ONL), initially extending and retracting highly dynamic neurite-like processes, tangential to the apical surface. Many photoreceptor progenitors presented a short apical primary cilium. The number and length of these cilia was gradually reduced until nearly disappearing around 60 hpf. Their disruption by knocking-down ift88 and elipsa caused a notorious defect on basal process retraction. To assess the role of cell adhesion in the organization of photoreceptor progenitors, we knocked-down cdh2/N-cadherin and observed the cell behavior by time-lapse microscopy. The ectopic photoreceptor progenitors initially migrated in an apparent random manner, profusely extending cell processes, until they encountered other cells to establish cell rosettes in which they stayed, acquiring photoreceptor-like polarity. Altogether, our observations indicate a complex regulation of photoreceptor progenitor dynamics to form the retinal ONL, previous to the post-mitotic maturation stages.
Morphogenesis of the lens placode
Authors: Magalhães Cecília G. , De Oliveira-Melo Maraysa , Yan C. Y. Irene
Published: September 2020

For over 100 years, the vertebrate eye has been an important model system to understand cell induction, cell shape change, and morphogenesis during development. In the past, most of the studies examined histological changes to detect the presence of induction mechanisms, but the advancement of molecular biology techniques has made exploring the genetic mechanisms behind lens development possible. Despite the particular emphasis given to the induction of the lens placode, there are still many aspects of the cell biology of lens morphogenesis to be explored. Here, we will revisit the classical detailed description of early lens morphological changes, correlating it with the cell biology mechanisms and with the molecules and signaling pathways identified up to now in chick and mouse embryos. A detailed description of lens development stages helps better understand the timeline of the events involved in early lens morphogenesis. We then point to some key questions that are still open.
LIN-35 beyond its classical roles: its function in the stress response
Authors: González-Rangel Alan A. , Navarro Rosa E.
Published: September 2020

The pocket protein family controls several cellular functions such as cell cycle, differentiation, and apoptosis, among others. However, its role in stress has been poorly explored. The roundworm Caenorhabditis elegans is a simple model organism whose genes are highly conserved during evolution. C. elegans has only one pocket protein, LIN-35; a retinoblastoma protein (pRB)-related protein similar to p130. To control the expression of some of its targets, LIN-35 interacts with E2F-DP (E2 transcription factor/dimerization partner complex) transcription factors and LIN-52, a member of SynMUV (Synthetic Muv) complex. Together, these proteins form the DRM complex, which is also known as the DREAM complex in mammals. In this review, we will focus on the role of LIN-35 and its partners in the stress response. It has been shown that LIN-35 is required to control starvation in L1 and L4 larval stages, and to induce starvation-induced germ apoptosis. Remarkably, during L1 starvation, insulin/IGF-1 receptor signaling (IIS), as well as the pathogenic, toxin, and oxidative stress-responsive genes, are repressed by LIN-35. The lack of lin-35 also triggers a downregulation of oxidative stress genes. Recent works showed that lin-35 and hpl-2 mutant animals showed enhanced resistance to UPRER. Additionally, hpl-2 mutant animals also exhibited upregulation of autophagic genes, suggesting that SynMuv/DRM proteins participate in this process. Finally, lin-35(n745) mutant animals overexpressed hsp-6, a chaperone that participated in the UPRmt. All of these data demonstrate that LIN-35 and its partners play an important role during the stress response.
Delineating the anuran axial skeleton
Authors: Sánchez Sara S. , Sánchez Romel S.
Published: September 2020

The axial skeleton of the anurans has undergone an evolutionary reduction of its bone elements. This structural plan is strongly preserved throughout the order and would have emerged as a highly specialized anatomical adaptation to its locomotor jumping pattern. The development programs that direct the vertebral morphogenesis of the anurans are poorly described and the molecular bases that have caused their pattern to differ from other tetrapods are completely unknown. In this work, we review the ontogeny of the spinal column of the anurans and explore the genetic mechanisms that could explain the morphological difference and the maintenance of the body plan during evolution. Here, we propose that the absence of caudal osseous elements, as a consequence of the inability of sclerotomes to form cartilaginous condensations in frogs, could be due to changes in both pattern and expression levels of Hox, Pax1, Pax9 and Uncx4.1 genes along the anteroposterior axis. The anteriorised expression of the Hox genes together with the reduction in the expression levels of Pax1, Pax9 and Uncx4 in the posterior somites could explain, at least partly, the loss of caudal vertebrae in the anurans during evolution.
Establishing embryonic territories in the context of Wnt signaling
Authors: Velloso Ian , Maia Lorena A. , Amado Nathalia G. , Reis Alice H. , He Xi , Abreu Jose G.
Published: September 2020

This review highlights the work that my research group has been developing, together with international collaborators, during the last decade. Since we were able to establish the Xenopus laevis experimental model in Brazil, we have been focused on understanding early embryonic patterns regarding neural induction and axes establishment. In this context, the Wnt pathway appears as a major player and has been much explored by us and other research groups. Here, we chose to review three published works which we consider to be landmarks within the course of our research and also within the history of modern findings regarding neural induction and patterning. We intend to show how our series of discoveries, when painted together, tells a story that covers crucial developmental windows of early differentiation paths of anterior neural tissue: 1. establishing the head organizer in contrast to the trunk organizer in the early gastrula; 2. deciding between neural ectoderm and epidermis ectoderm at the blastula/gastrula stages, and 3. the gathering of prechordal unique properties in the late gastrula/early neurula.
La construcción secular de un espacio funerario mediante distintas arquitecturas monumentales: primeras consideraciones tras las investigaciones en la Cobertoria (Salas, Asturias)
Authors: Rodríguez del Cueto Fernando , Busto Zapico Miguel
Published: September 2020

El Proyecto de la Cobertoria está desarrollando desde 2015 dos líneas principales de actuación. Por un lado, la revisión del inventario arqueológico del concejo de Salas con prospecciones y análisis LiDAR para descubrir nuevas tumbas o comprender mejor las ya conocidas. Por el otro, excavaciones arqueológicas en megalitos de interés para estudiar el grado de implantación de las primeras sociedades agropecuarias en el centro-occidente de Asturias. La segunda línea de trabajo se centra en las excavaciones del túmulo de la Cobertoria, incluido en la necrópolis de la sierra de San Juan. Aquí se dan a conocer los resultados preliminares de la secuencia estratigráfica de este enclave y sus fases constructivas prehistóricas, todas ellas datadas radiométricamente. Diacronías y proyectos arquitectónicos muy diferentes, desarrollados todos ellos en un largo ciclo temporal, han salido a la luz estos años. La importancia del monumento trasciende además más allá de la Prehistoria, ya que los expoliadores acudieron atraídos por el conjunto de leyendas y nombres singulares que se concentran en el lugar.
Caracterización de la distribución de terra sigillata hispánica tardía meridional en la comarca del Alto Almanzora (Almería)
Authors: López Medina María Juana , Pérez Martinez Francisco
Published: September 2020

En el presente artículo analizamos la presencia de terra sigillata hispánica tardía meridional (TSHTM) en los yacimientos del Valle Alto del río Almanzora (Almería) durante la Antigüedad Tardía (ss. IV-VIII) a partir de los datos del proyecto de prospección “Estudio del proceso histórico durante la Prehistoria y la Antigüedad en la cuenca del Alto Almanzora”. Para ello se tiene en cuenta la relación de estas vajillas finas regionales con la estructura del poblamiento, sus canales de distribución y la importación de cerámicas finas procedentes del Norte de África, especialmente la terra sigillata africana C y D. Su comparación estadística marca unas tendencias similares a contextos de excavaciones en el Sureste peninsular.
La proyección exterior de la arqueología española a través de los congresos arqueológicos internacionales (1900-1936)
Authors: Casado Rigalt Daniel , Mederos Martín Alfredo
Published: September 2020

Los congresos internacionales son un medio excelente para valorar la primera proyección de la arqueología española en Europa y América hasta el estallido de la Guerra Civil. Se pueden distinguir tres grandes fases, 1900-1913, 1914-1922 y 1923-1936. En la primera etapa, los principales arqueólogos extranjeros que trabajaban en España, Breuil, Obermaier o Schulten, publicaron principalmente en revistas francesas y alemanas. En cambio, fue Siret quien utilizó más estos congresos para proyectar su investigación en el extranjero, que eludieron investigadores españoles como Gómez-Moreno y Catalina García. En otros casos como Mélida y Rivero, representaron a España en los congresos de Arqueología Clásica de El Cairo y Roma, pero no presentaron trabajos. Durante el parón por la Primera Guerra Mundial de una década entre 1914-22, que impidió la celebración en Madrid del XV Congreso Internacional de Antropología y Arqueología Prehistórica en 1915, obtenido gracias a las gestiones de Cerralbo, se produjo la incorporación a cátedras de Bosch Gimpera en 1916 y Obermaier en 1922, a la vez que como directores de museos lo hicieron Taracena en 1916 y Cabré en 1922. A ellos se sumaron en la universidad, pocos años después, Pericot y Mergelina en 1925, Carriazo en 1927 o Castillo y García Bellido en 1931. Bosch Gimpera fue el investigador con mayor proyección internacional desde 1923, inicialmente con apoyo económico del Institut d’Estudis Catalans y la culminó como secretario del IV Congreso Internacional de Arqueología Clásica en Barcelona (1929), que sirvió para debutar en estos congresos a investigadores como Juan Cabré, Encarnación Cabré, Navascués, Pérez de Barradas, Pericot o Taracena, quienes comenzaron a asistir ya más regularmente presentando trabajos en Coimbra-Oporto (1930), Argel (1930), Londres (1932) o las previstas inicialmente para Oslo (1936). Otro cambio importante, después de numerosas ausencias, fue la participación significativa de americanistas interesados en la América Precolombina a partir del congreso de Sevilla (1935). Las dos conclusiones principales de este trabajo son que el peso de los investigadores extranjeros en la arqueología española fue mucho menor de lo que se ha pensado, incluso en el primer periodo hasta 1913, diluyéndose posteriormente. En segundo lugar, la proyección científica de Bosch Gimpera antes de la Guerra Civil y de Pericot después estuvo basada en la activa participación de ambos en congresos internacionales.
Internet das Coisas Robóticas: Desenvolvimento de um protótipo para o ensino de programação
Authors: Jaime Alves Gabriel , Roberto Beleti Junior Carlos , Pinto Moreira André , Beatrys Ruiz Aylon Linnyer , Eloise Flôr Daniela
Published: September 2020

Aiming at addressing the principles of programming logic and developing problem analysis and problem solving skills, the discipline of algorithms and programming is present in the curricula of various courses, from computer science courses to engineering. In the literature, some studies have shown that such disciplines usually present high percentages of dropout and disapproval due to several factors, but mainly difficulties of abstraction as to the logic required to solve problems using programming. To contribute to these factors, it is envisaged to provide ways of teaching that help the student to reason and find solutions to problems with programming. One method that may be most effective is block programming, because it aims to facilitate the introduction of programming concepts to students. Block programming, unlike traditional programming, is more interactive and visual, consisting of blocks that represent computational instructions, where blocks are connected to others to be able to perform programming. Thus, this research presents the development of an IoRT-based prototype along with block programming to promote computational thinking, more specifically in the teaching of algorithms and programming. The internet of robotic things emerges as an emerging vision that brings together objects focused on the production of action, autonomous behavior and especially interaction. IoRT presents itself as a great ally for teaching, focusing on promoting student engagement and expanding teaching possibilities.
Avaliando o Desempenho da Abordagem de Comitê na Análise de Sentimentos na Língua Portuguesa
Authors: Henrique Cardoso Matheus , Maria da Rocha Fernandes Anita
Published: September 2020

Sentiment Analysis aims extract subjective information from texts that, when written in Portuguese face a number of difficulties related to grammatical nature and vocabulary diversity. In order to collaborate with researches in this area, this paper presents the proposal to evaluate the performance of the committee approach in relation to the traditional approaches of sentiment analysis in the Portuguese language context. As object of application we choose tweets about volleyball theme that will serve as basis for the approaches application. These texts will be treated using Natural Language Processing for better performance of the algorithms. Other approaches will also be used in this study to assist in the evaluation of the committee along with the aid of metrics such as accuracy, precision, recall and F-measure.
Aplicação de Mineração de Dados para o Auxílio da Tomada de Decisão em Gestão de Pessoas
Authors: Brati Favarin Samuel , Ballottin Martins Rafael
Published: September 2020

People are the foundation of organizations. For companies remain competitive, they need to develop and maintain their human resources. Professionals of the area, must rely on data to make their decisions, otherwise, it can generate bad decisions, taken only by intuition or experience. In this context, this project aimed to help the future decision making process made by human resource specialists of a People Management Software Company using the KDD process to generate new knowledge. In the data mining stage were used The Decision Tree, Neural Network, APRIORI and K-Means algorithms, generating patterns to be analysed with human resource specialists. Preliminary results demonstrate that it is possible to observe standards that classify employees as highly engaged, engaged, neutral and disengaged.
Previsão de Geração de Energia em uma Usina Eólica a partir de Séries Temporais
Authors: Victor Florencio de Souza Manoel , Cuevas Rodriguez Luis , Trinchet Varella Carlos
Published: September 2020

Forecasting the generation of renewable energy is necessarymainly for the operators of these systems, in the fieeld of windenergy it is no diffeerent, especially considering the inconstancyand unpredictability of the wind behavior. Theerefore, this paperproposes and evaluates diffeerent models based onmachine learning aiming at this problem, with emphasis on awind farm located on the coast of Cuba. Thee results of the workwere used to develop an operational monitoring system forthe plant capable of emittiing alarms when the actual energygeneration is diffeerent from the generation made by the model.