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Correlations between student connectivity and academic performance: A pandemic follow-up

Physical Review physics Education Research 2023年第1期19卷 010106-010106页

作者： Nathan Crossette Lincoln D. Carr Bethany R. Wilcox Department of Physics University of Colorado Boulder Boulder Colorado 80309 USA Quantum Engineering Program Colorado School of Mines Golden Colorado 80401 USA Department of Physics Colorado School of Mines Golden Colorado 80401 USA Department of Applied Mathematics and Statistics Colorado School of Mines Golden Colorado 80401 USA

Social network analysis (SNA) has been gaining traction as a technique for quantitatively studying student collaboration. We analyze networks, constructed from student self-reports of collaboration on homework assignments, in two courses from the University of Colorado Boulder and one course from the Colorado School of Mines. All three courses occurred during the COVID-19 pandemic, which allows for a comparison between the course at the Colorado School of Mines (in a fully remote format) with results from a previous pre-pandemic study of student collaboration at the Colorado School of Mines (in an in-person format), as well as comparison between the Mines results with the two University of Colorado courses (in a hybrid format). We compute nodal centrality measures and calculate the correlation between student centrality and performance. Results varied widely between each of the courses studied. The course at the Colorado School of Mines had strong correlations between many centrality measures and performance which matched the patterns seen in the pre-pandemic study. The courses at the University of Colorado Boulder showed weaker correlations, and one course showed nearly no correlations at all between students’ connectivity to their classmates and their performance. Taken together, the results from the trio of courses indicate that the context and environment in which the course is situated play a more important role in fostering a correlation between student collaboration and course performance than the format (remote, hybrid, in-person) of the course, a finding which has implications for the broader use of SNA within physics education research. Additionally, we conducted a short study on the effect that missing nodes may have on the correlations calculated from the measured networks, an analysis largely missing from the SNA literature within PER. This investigation showed that missing nodes tend to shift correlations towards zero, providing evidence that the stati

关键词： Learning environment Research methodology Upper undergraduate students

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Using optical coherence tomography images to evaluate fungal growth in reline resins

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Journal of Innovative Optical Health Sciences 2023年第3期16卷 113-123页

作者： Mayra M.Aquino Caio B.S.Maior Nathália A.E.Lins Cláudia C.B.O.Mota Patricia L.A.Nascimento 3nderson S.L.Gomes Graduate Program in Dentistry Universidade Federal de Pernambuco(UFPE)Recife Brazil Center of Risk Analysis Reliability Engineering and Environmental Modeling Universidade Federal de Pernambuco(UFPE)Recife Brazil Faculty of Dentistry Centro Universitario Tabosa de Almeida(ASCES)Caruaru Brazil Department of Physics Universidade Federal de Pernambuco(UFPE)Recife Brazil

As changes in hard or soft oral tissues normally have a microbiological component,it is important to develop diagnostic techniques that support clinical evaluation,without destroying microbio-logical *** optical coherence tomography(OCT)represents an alternative to analyze tissues and microorganisms without the need for *** imaging technique could be defined as a fast,real-time,in situ,and non-destructive ***,this study proposed the use of the OCT to visualize biofilm by Candida albicans in reline resins for removable *** reline resins(Silagum-Comfort,Coe Comfort,and Soft-Confort),with distinct char-acteristics related to wa ter sorption and fungal inhibition were used.A total of 30 samples(10 for each resin group)were subjected to OCT scanning before and 96 h after inoculation with Candida albicans(URM 6547).The biofilm analysis was carried out through a 2D optical Callisto SD-OCT(930 nm)operated in the spectral ***,the images were preprocessed using a3×3 Gaussian filter to remove the noise,and then Otsu binarization,allowing segmentation and pixel *** layer's biofilm formed was clearly defined and,indeed,its visualization is modified by water sorption of each ***-Comfort and *** showed some similarities in the scattering of light between the clean and inoculated samples,in which,the latter samples presented higher values of light signal ***-Comfort samples were the only ones that showed no di®erences between the clean or inoculated ***,the results of this study suggest that OCT is a viable technique to visualize the biolm in reline *** in the literature are still scarcely using the OCT technique to visualize biolm in reline resins,further studies are *** should not contain any references or displayed equations.

关键词： OCT reline resin biofilm removable prosthesis.

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Temporal Mode Conversion in a Waveguide by Fast Motion of its Plates

Temporal Mode Conversion in a Waveguide by Fast Motion of it...

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CLEO: Fundamental Science, CLEO:FS 2024 - Part of Conference on Lasers and Electro-Optics, CLEO 2024

作者： Solís, Diego M. Yin, Shixiong Galiffi, Emanuele Alù, Andrea Engheta, Nader Departamento de Tecnología de los Computadores y de las Comunicaciones University of Extremadura Cáceres10003 Spain City University of New York Photonics Initiative Advanced Science Research Center New York10031 United States City University of New York Physics Program Graduate Center New York10031 United States Department of Electrical and Systems Engineering University of Pennsylvania PhiladelphiaPA19104 United States

ISBN: (纸本)9781957171395

We show, semi-analytically and numerically, how the relativistic accelerated motion of a waveguide's parallel plates induces fast mode conversion including reflection, similar to the temporal interface by sudden variation of interplate distance through conductivity switching. © Optica Publishing Group 2024 © 2024 The Author(s)

关键词： Waveguides

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engineering Topological States in Arrays of Two-mode Nanostructured Dielectric Waveguides

Engineering Topological States in Arrays of Two-mode Nanostr...

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Progress in Electromagnetic Research Symposium (PIERS)

作者： A. O. Mikhin V. Rutckaia R. S. Savelev I. S. Sinev A. Alù M. A. Gorlach School of Physics and Engineering ITMO University Saint Petersburg Russia Photonics Initiative Advanced Science Research Center The City University of New York New York USA Centre for Innovation Competence SiLi-Nano Martin-Luther-University Germany Physics Program Graduate Center The City University of New York New York USA

ISBN: (数字)9798350375909

ISBN: (纸本)9798350375916

Designs of the optical structures that support topologically nontrivial states typically rely on the combining of simple single-mode meta-atoms in a lattice with a symmetry that guarantees the occurrence of the topological states. Here, we explore an alternative approach that does not require the use of complex lattice geometries, but instead relies on the tailoring of the spatial distribution of the near fields in the individual meta-atoms operating in the multi-mode regime. To this end we consider specially designed subwavelength grating dielectric waveguides with two quasi-degenerate modes that interfere in the near-field zone leading to highly asymmetric field patterns of the propagating waves. We show that a one-dimensional array of such waveguides exhibits non-trivial topological properties and supports topological edge states even with one waveguide in the unit cell. Theoretical predictions are confirmed experimentally by visualizing the excited states of the array by measuring the intensity of the radiation at the frequency of the third harmonic.

关键词： Visualization Lattices Electromagnetic waveguides Waveguide lasers Optical waveguide theory Frequency measurement Dielectrics

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Terahertz phonon polariton concentrator based on perovskite oxides

Terahertz phonon polariton concentrator based on perovskite ...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Rui Xu Tong Lin Jiaming Luo Xiaotong Chen Elizabeth R. Blackert Alyssa R. Moon Khalil M. JeBailey Hanyu Zhu Department of Materials Science and Nano Engineering Rice University Houston U.S.A. Applied Physics Graduate Program Rice University Houston U.S.A. Nanotechnology Research Experience for Undergraduates (Nano REU) Program Rice University Houston U.S.A.

We report the experimental demonstration of surface phonon-polaritonic devices in a broad spectral range of 7-13 THz based on SrTiO 3 . We designed planar ultrafast concentrators that amplifies transient electric fiel... 详细信息

ISBN: (纸本)9781957171258

关键词： Concentrators Electric fields Fast Fourier transforms Field enhancement Fused silica Second harmonic generation

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Machine learning-based analysis of multiple simultaneous disturbances applied on a transmission-reflection analysis based distributed sensor using a nanoparticle-doped fiber

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Photonics Research 2023年第3期11卷 364-372页

作者： LETíCIA AVELLAR ANSELMO FRIZERA HELDER ROCHA MARIANA SILVEIRA CAMILO DíAZ WILFRIED BLANC CARLOS MARQUES ARNALDO LEAL-JUNIOR Graduate Program of Electrical Engineering Federal University of Espirito SantoVitoria 29075-910Brazil Université Cote d'Azur Institut de Physique de NiceCNRS06108 Nice Cedex 2France I3N and Physics Department Universidade de AveiroCampus Universitário de SantiagoAveiro 3810-193Portugal

Photonic technology combined with artificial intelligence plays a key role in the development of the latest smart system trends,integrating cutting-edge technology with machine learning *** paper proposes a transmission-reflection analysis based system using dielectric nanoparticle-doped fiber combined with artificial intelligence to address one of the major problems in the distributed sensing approach:reducing the cost while maintaining high spatial resolution to close the gap between distributed sensors and the general *** learning-based models are designed to classify the perturbed positions when the same force is used and force regression when different forces are applied on each *** results show an accuracy of 99.43%in the position classification of multiple disturbances and an rms error of 1.53 N in the force regression,which represents 5%of the force *** addition,a smart environment using the current system is proposed,which presented 100%accuracy in identifying the positions of different persons in the *** smart environment enables remote home care of patients with high reliability,intelligent decision-making,and a predictive capability.

关键词： smart fiber positions

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Third-Order Optical Properties of Ag Nanocubes and Ag-Au Hollow Nanostructures Investigated by Femtosecond Z-Scan Measurements

SSRN

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SSRN 2024年

作者： Sousa, Claudevan A. Melo, Antonio F.A.A. Silva, Nefe J.B. Silva, Tânia Patrícia Silva E. Viana, Bartolomeu C. Santos, Francisco Eroni P. Garcia, Hans Department of Physics UFPI - Universidade Federal do Piauí PI Teresina64049-550 Brazil Materials Engineering Graduate Program Federal Institute of Education Science and Technology of Piauí Central Campus PI Teresina64000-040 Brazil Interdisciplinary Laboratory for Advanced Materials BioMatLab group Materials Science & Engineering Graduate Program UFPI - Universidade Federal do Piauí PI Teresina64049-550 Brazil

In this work, we reported experimental investigations on third-order optical properties of aqueous colloidal dispersions of silver nanocubes (Ag-NCs) and Ag-Au hollow nanostructures. The hollow bimetallic are nanoboxes, that were synthesized by galvanic substitution using silver nanocubes as templates, inserting silver with gold in molar ratios of 1.5 and 3.0 mL. This process adjusted tuning the Surface Plasmon Resonance (SPR) compared to the original Ag-NCs nanocubes. Femtosecond Z-scan measurements performed at 1040 nm, 350fs and laser intensities from 99.7 - 279 GW/cm2 shows negative nonlinear refraction for both nanocube and nanoboxes colloids, attributed to hot electron generation. Solvent effects are simultaneously suppressed of the nanostructures. On the other hand, the non-linear absorption observed for bimetallic nanoboxes shows the presence of saturated absorption (SA), but the Ag-NCs do not show a non-linear absorption signal. Therefore, our experimental results provide a reliable reference for the application of these bimetallic nanostructures as active media in nonlinear photonic devices. © 2024, The Authors. All rights reserved.

关键词： Surface plasmon resonance

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Recent Advancements in Nanophotonics for Optofluidics

arXiv

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arXiv 2024年

作者： Yang, Sen Hong, Chuchuan Zhu, Guodong Anyika, Theodore Hong, Ikjun Ndukaife, Justus C. Institute of Physics Chinese Academy of Sciences Beijing National Laboratory for Condensed Matter Physics Beijing100190 China Department of Chemistry Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Electrical and Computer Engineering Vanderbilt University NashvilleTN37235 United States Department of Mechanical Engineering Vanderbilt University NashvilleTN37235 United States Interdisciplinary Materials Science Program Vanderbilt University NashvilleTN37240 United States

Optofluidics is dedicated to achieving integrated control of particle and fluid motion, particularly on the micrometer scale, by utilizing light to direct fluid flow and particle motion. The field has seen significant growth recently, driven by the concerted efforts of researchers across various scientific disciplines, notably for its successful applications in biomedical science. In this review, we explore a range of optofluidic architectures developed over the past decade, with a primary focus on mechanisms for precise control of micro and nanoscale biological objects and their applications in sensing. Regarding nanoparticle manipulation, we delve into mechanisms based on optical nanotweezers using nanolocalized light fields and light-based hybrid effects with dramatically improved performance and capabilities. In the context of sensing, we emphasize those works that used optofluidics to aggregate molecules or particles to promote sensing and detection. Additionally, we highlight emerging research directions, encompassing both fundamental principles and practical applications in the field. Copyright © 2024, The Authors. All rights reserved.

关键词： Flow of fluids

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Coercivity Enhancement in Hematite/Permalloy Heterostructures Across the Morin Transition

SSRN

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SSRN 2024年

作者： Wang, Tianxing Damir Basaran, Ali Cemil Hage, Ralph El Li, Junjie Navarro, Henry Torres, Felipe E. de la Fuente, Oscar Rodríguez Schuller, Ivan K. Department of Physics Center for Advanced Nanoscience University of California San Diego92093 United States Materials Science and Engineering Program University of California–San Diego La Jolla CA92093 United States Department of Physics Universidad de Chile Santiago7800024 Chile Universidad Complutense de Madrid Madrid Spain

Interfacial effects between antiferromagnetic (AFM) and ferromagnetic (FM) materials have long been a center of magnetism studies. Aside from the exchange bias occurring at the AFM/FM interface, controlling the coercivity is another significant topic in magnetic recordings. The coercivity of FM materials is often determined through varying grain size, alloy composition, density of defects, etc., which is set during material growth and offers limited room for modification after growth. Hematite ( ) is an AFM material that undergoes a temperature-controlled spin-flip transition, the so-called Morin transition. This transition gives an extra degree of freedom making hematite an intriguing component to study the exchange coupling when interfaced with an FM material. In this work, changes in the magnetic properties of soft magnetic permalloy ( or Py) thin films grown on hematite were studied across the Morin transition. Surprisingly, these samples showed a remarkable change in coercivity during the Morin transition. We attribute this effect to the magnetic domain mixture of hematite during the Morin transition. Our findings present a novel method of controlling the coercivity of plain ferromagnetic thin films. © 2024, The Authors. All rights reserved.

关键词： Coercive force

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Electronic Readout for a 100 ps CTR PET Detector with 24:1 Multiplexing Ratio of Timing Channels

Electronic Readout for a 100 ps CTR PET Detector with 24:1 M...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Shirin Pourashraf Andrea Gonzalez-Montoro Derek Innes Joshua W. Cates Craig S. Levin Department of Radiology Stanford University Stanford CA USA Applied Nuclear Physics Program Lawrence Berkeley National Laboratory Berkeley CA USA Departments of Radiology Bioengineering Physics and Electrical Engineering Molecular Imaging Program Stanford University Stanford CA USA

We have designed a novel electronic readout with 24:1 multiplexing ratio of the timing channels that achieves 100 ps coincidence time resolution. The detector layer units comprise 2×4 arrays of 3×3×10 mm 3 "LGSO" crystals side-coupled to 6×4 arrays of 3×3 mm 2 SiPMs. To achieve low power dissipation and scalability of this readout design, its effective area is implemented in only 13.3 mm using compact and power efficient electronic components. The measured CTR of the 24:1 multiplexed timing channels (or 8:1 LVDS signals) was 107.0 ± 3.6 ps FWHM using a 22 Na point-source and a very low timing jitter FPGA-based TDC.

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