bluuebunny/crossref_metadata_2025 huggingface dataset:
Is the Gender Pay Gap Largest at the Top?
Authors: Binder Ariel J. , Eng Amanda , Houghton Kendall , Foote Andrew
Published: May 2024

Conditional quantile regressions reveal that, while the gender pay gap at the top percentiles is largest among the most educated, the gap at the bottom percentiles is largest among the least educated. Gender differences in work hours create more pay inequality among the least educated than they do among the most educated. The pay gap has declined throughout the distribution since 2006, but it has declined more for the most educated women. Current economics-of-gender research focuses heavily on the top end; equal emphasis should be placed on mechanisms driving gender inequality for non-college-educated workers.
(Empirical) Bayes Approaches to Parallel Trends
Authors: Kwon Soonwoo , Roth Jonathan
Published: May 2024

We consider Bayes and Empirical Bayes (EB) approaches for dealing with violations of parallel trends. In the Bayes approach, the researcher specifies a prior over both the pretreatment violations of parallel trends delta-pre and the posttreatment violations delta-post. The researcher then updates their posterior about the posttreatment bias delta-post given an estimate of the pre-trends delta-pre. This allows them to form posterior means and credible sets for the treatment effect of interest, Delta-post. In the EB approach, the prior on the violations of parallel trends is learned from the pretreatment observations. We illustrate these approaches in two empirical applications.
Comparative Advantage of Humans versus AI in the Long Tail
Authors: Agarwal Nikhil , Huang Ray , Moehring Alex , Rajpurkar Pranav , Salz Tobias , Yu Feiyang
Published: May 2024

Machine learning algorithms now exceed human performance on several predictive tasks, generating concerns about widespread job displacement. However, supervised learning approaches rely on large amounts of high-quality labeled data and are designed for specific predictive tasks. Thus, humans may be required for a large number of tasks, each of which is not commonly encountered—the long tail—because humans can make predictions for a broader range of outcomes and with exposure to much less data. We show that a self-supervised algorithm for chest X-rays, which does not require specifically annotated disease labels, closes this gap even in the long tail of diseases.
Measuring the Market for Legal Firearms
Authors: Armona Luis , Rosenberg Adam M.
Published: May 2024

The Massachusetts Firearms Records Bureau recently published administrative data covering the universe of legal firearm transactions in the state. We use these data to validate state-level background checks as a proxy for firearm transactions and show that historical trends in transactions within Massachusetts align with the rest of the United States. Using auxiliary data from a national survey, we show that the Massachusetts dataset can detect patterns in the demographics of both gun ownership and type of firearm purchased. Our analysis suggests that this dataset is a promising source of information for studying interactions in the market for legal firearms.
Setting the Record Straight on Racial Wealth Inequality
Authors: Addo Fenaba R. , Darity William A. , Myers Samuel L.
Published: May 2024

The racial wealth gap in the United States is the object of much misrepresentation and misunderstanding. Our paper is intended to provide a corrective. We will address how the mainstream economic view of the drivers of racial disparities in wealth is a human capital view that promotes anti-Black and personal responsibility narratives while ignoring the significance of the racially uneven transmission of resources across generations. It also fails to acknowledge the cumulative impact of US racial history on present wealth gaps.
Improved flap perfusion and hemostasis after postoperative embolization in free flap surgery: a case report
Authors: Kim Junghee , Kwon Hyeokjae , Kim Sunje , Song Seung Han , Oh Sang-Ha , Ha Yooseok
Published: May 2024

This study aims to present a novel use of coil embolization in managing postoperative bleeding after free flap surgery, a technique typically reserved for other medical complications. We report the case of a 77-year-old female patient who underwent muscle-sparing latissimus dorsi free flap surgery for recurrent myxofibrosarcoma on her left thigh. Although hemostasis was achieved hemostasis during surgery, the patient experienced postoperative bleeding, which was initially managed with compression and blood transfusions. Upon a critical drop in the hemoglobin level, coil embolization was performed at the proximal segment of the descending branch of the lateral circumflex femoral artery. Coil embolization successfully controlled bleeding, while preserving blood flow to the flap. The patient’s hemoglobin levels stabilized, and the flap’s perfusion improved post-procedure. This approach proved effective in managing bleeding in areas other than the anastomosis site, with the patient showing a satisfactory recovery and no significant complications in the 30-day postoperative period. Coil embolization, a method commonly used for gastrointestinal bleeding and other vascular issues, can be a viable and effective option for controlling postoperative bleeding after free flap surgery. This case demonstrates its potential as a lifesaving intervention while preserving flap viability. However, further research with more cases is needed to evaluate the generalizability and long-term outcomes of this technique in similar surgical contexts.
Pathways for Design Research on Artificial Intelligence
Authors: Abbasi Ahmed , Parsons Jeffrey , Pant Gautam , Sheng Olivia R. Liu , Sarker Suprateek
Published: May 2024

An expanding body of information systems research is adopting a design perspective on artificial intelligence (AI), wherein researchers prescribe solutions to problems using AI approaches rather than describing or explaining AI-related phenomena being studied. In this editorial, we address some of the challenges faced in publishing design research related to AI and articulate viable pathways for publishing such work. More specifically, we highlight six major impediments, use the explosion in the state of the art for large language models to underscore these impediments, propose some pathways for overcoming the impediments, and use several example articles to illustrate how the pathways can be followed for different types of AI-related design artifacts.

History: Senior Editor; Associate Editor.

Funding: A. Abbasi was funded by the National Science Foundation (NSF) [Grants 2240347 and IIS-2039915] and a Kemper Faculty Award. J. Parsons was funded by the Natural Sciences and Engineering Council of Canada (NSERC) [Grant RGPIN-2020-04916].
Educação de jovens e adultos:
Authors: Bueno Olga Mara , Da Silva Oliveira Rita de Cássia
Published: May 2024

Este texto discorre sobre política educacional e a educação inclusiva de pessoas com deficiência na educação de jovens e adultos no Brasil. Tem como objetivo refletir sobre os desafios que a pesquisa em política educacional vivencia no Brasil no campo das políticas educativas que reverberam na implementação da educação inclusiva para pessoas com deficiência, sobretudo jovens e adultas, por meio de uma pesquisa de revisão narrativa de literatura. Organizam-se metodologicamente a partir de fundamentação teórica, com base precípua de consulta, publicações do Grupo de Trabalho (GT 05 – Estado e Política Educacional), da Associação Nacional de Pós-Graduação e Pesquisa em Educação (ANPEd), e de autores que sustentam a necessidade de posicionamento da pesquisa em política educacional para a democratização da educação. Para isso, divide-se em três partes:1) a contextualização das políticas e prioridades para a educação básica, adotadas pelos governos eleitos a partir do ano de 2018; 2) a política de educação inclusiva e a pessoa com deficiência na educação de jovens e adultos; 3) reflexões sobre alguns desafios, que implicam responsabilidades na investigação e produção de conhecimentos acerca das políticas educacionais, especialmente, no campo da educação inclusiva para pessoas com deficiência na educação de jovens e adultos. Traz como resultado, reflexões contributivas à problematização das políticas de educação inclusiva para pessoas com deficiência na educação de jovens e adultos na contemporaneidade.
Aprender por toda a vida:
Authors: Silva Francisco Canindé
Published: May 2024

Esse texto, de caráter ensaístico, tem como temática a educação de jovens, adultos e idosos (EJA), a partir de uma compreensão gnosiológica de que se aprende por toda a vida em diferentes espaçostempos educativos, reconhecidamente a partir da condição humana de inacabamento, inconclusão e incompletude. Objetiva-se, com o referido ensaio, apresentar a professores, pesquisadores e militantes dessa modalidade educativa algumas concepções que vêm constituindo o fundamento filosófico do aprender por toda a vida, com ênfase na ideia de redistribuição social e reconhecimento cultural, enquanto discussão balizadora que desafia, no tempo presente, o trabalho político e pedagógico de educadores da EJA. O diálogo reflexivo, como procedimento metodológico, possibilitou a reconstrução e dilatação de compreensões acerca do ato educativo em questão – aprender por toda a vida —, tomando como recurso disparador perguntas problematizadoras capazes de impulsionar inquietações e produzir arquiteturas emancipatórias acerca da modalidade. Entre elas, destaca-se a energia e a força do pensamento sistêmico-recursivo, representado pela metáfora da rede, na qual articulam-se processos e possibilidades educativas, coerentes com as reais necessidades dos sujeitos que lutam por reconhecimento e distribuição social justa.
O que mudou na educação de jovens e adultos no Brasil pós-ditadura?
Authors: Fernanda de Freitas Bárbara , De Rezende Pinto José Marcelino
Published: May 2024

A literatura mostra que, em toda a história da educação brasileira, a educação de jovens e adultos (EJA) ocupa um lugar marginal no âmbito das políticas públicas. Em geral, a modalidade é relegada a ações e programas fragmentados que não se constituem como políticas de Estado. Este trabalho buscou, a partir de revisão da literatura e da legislação, revisitar o histórico de políticas voltadas à EJA a partir do processo de redemocratização, iniciado em 1985, até os dias atuais. A análise nos permitiu reforçar o entendimento de que a subalternidade da modalidade é atravessada, substancialmente, pela falta de financiamento adequado. Ainda que o direito à EJA seja assegurado pela Constituição Federal, conclui-se que este ainda não foi concretizado, mesmo com a inclusão da modalidade na política de fundos. Portanto, é urgente um maior comprometimento por parte dos entes federados, em especial da União, para que este direito seja garantido aos milhões de jovens e adultos que o tiveram negado.
Os sentidos da alfabetização na narrativa de vida dos alunos da EJA
Authors: Penha Monteiro Brito Pavini Daniela , Paiva Assolini Filomena Elaine
Published: May 2024

A alfabetização transforma a concepção que os sujeitos têm sobre sua própria história de vida. Entender de que maneira essa transformação se dá, a partir da Análise de Discurso de matriz francesa e dos pressupostos da Teoria Sócio-histórica do Letramento, é o objetivo principal da pesquisa de mestrado apresentada no presente artigo. Compreendendo a EJA (Educação de Jovens e Adultos) a partir da perspectiva discursiva, como um espaço político organizado para preencher lacunas sociais de um país desigual, buscamos conhecer as trajetórias de vida de seus alunos, bem como os movimentos que eles empreendem em busca da possibilidade de ler e escrever, e de decodificar a língua. Mobilizando conceitos de narrativa que ratificam a importância dos espaços de escuta e fala no processo de criação de sentidos e encontro de si, criamos tais espaços, por meio das entrevistas, que são base para a constituição de nosso corpus.
Aprendizagem infindável e perda de prestígio das instituições de ensino superior
Authors: Oliveira Erinaldo , Saraiva Karla
Published: May 2024

O objetivo do artigo é analisar como os sujeitos trabalhadores atualmente são direcionados para uma constante renovação de habilidades por meio de uma aprendizagem infindável. Mais especificamente, pretende-se mostrar as estratégias para a constituição de sujeitos que buscam na aprendizagem ao longo da vida um meio de permanecer no mercado. A empiria é constituída por matérias do jornal Valor Econômico e entrevistas com quatro trabalhadores. A análise identifica e discute estratégia argumentativa que afirma que as instituições de ensino superior já não conseguem assegurar uma aprendizagem que garanta a permanência no mercado de trabalho. A partir dessa estratégia, são apresentados três focos de análise: a redefinição dos papéis e atribuições dos professores, a constituição de um aprendiz ativo e autônomo e, por fim, a necessidade de que essa aprendizagem seja mediada por tecnologias digitais. É perceptível uma convergência entre os enunciados presentes nas matérias do jornal e nas entrevistas, mostrando que a mídia e os indivíduos compartilham de um mesmo regime de verdade acerca de uma aprendizagem que capacita para o trabalho.
Educação popular, educação ao longo da vida e o letramento digital de pessoas idosas:
Authors: Nunes dos Santos André Luís , Batista Machado Aline Maria
Published: May 2024

Este estudo tem como foco temático a ligação entre as perspectivas da educação popular e da educação ao longo da vida com a prática social de pessoas idosas, voltando-se para os debates acerca dos elos e das contradições encontradas nesta relação. O objetivo geral da pesquisa foi discutir estas conexões sob um prisma amplo, elucidando algumas questões que perpassam estas temáticas, as quais vão desde a adequação mercadológica na fabricação de novas tecnologias para o público idoso ao processo de construção da autonomia propiciado pelas funcionalidades dos aparelhos tecnológicos. Concernente aos aspectos teórico-metodológicos da investigação, o artigo possui abordagem qualitativa, objetivos exploratórios e se caracteriza por ser bibliográfico, resultado, portanto, de uma dissertação de mestrado. A partir das análises, observou-se que o letramento digital, aliado as perspectivas da educação popular e da educação ao longo da vida, pode contribuir positivamente para as vivências sociais das pessoas idosas nas mais variadas esferas da sociedade.
Supporting social & emotional skills
Authors: Halls Christopher
Published: May 2024

In the second article in a three-part series, Dr Christopher Halls, head of Early Years at Dulwich Prep London, explores some of the sustained consequences of the pandemic and national lockdowns on children's current attainment in early years.
Setting the Panamanian Stage
Authors: Schlinger Barney A.
Published: May 2024

The creation of the nation of Panama opened the door for the United States to complete construction of the Panama Canal in 1914. To preserve the canal’s watershed, forests around the canal, and on islands in the canal, were protected, including Barro Colorado Island, which became a premier site for studies of tropical biology. It is here that Frank Chapman studied a remarkable bird, now known as the Golden-collared manakin (Manacus vitellinus). This book is the story of the extraordinary biology of this small, but mighty, bird.
Male Manakins Are Rich with Androgen Targets
Authors: Schlinger Barney A.
Published: May 2024

Androgens are a class of hormones that bind to androgen receptors (AR) to promote significant changes to cells possessing AR. Testosterone is made more potent by its conversion to 5-dihydrotestosterone (DHT) by the enzyme 5-reductase. Studying the way androgens act on AR receptors in a small wild tropical bird can be challenging. Using a variety of techniques, male golden-collared manakins were found to possess 5-reductase and AR at high levels in spinal motor and sensory neurons, in the brain and in skeletal muscles important for the performance of courtship displays, including wingsnapping. Across a diversity of birds, including several manakins, the amount of androgen receptor in muscle is found to correlate with the complexity of courtship behavior, evidence that androgen action on muscle is key to the physicality of avian courtship behavior.
The Future Matters
Authors: Sayen Jamie
Published: May 2024

In the 1990s, Mitch Lansky orchestrated the development of the Maine Low-Impact Forestry project. In contrast to industrial forestry, low impact logging operations internalize externalities. Huge subsidies to industrial forestry, including externalities, undermine the profitability of low-impact forestry. The chapter concludes with a profile of David Brynn and Vermont Family Forests’ implementation of low-impact forestry and the beginnings of a locally owned, value-added, low-impact timber economy in Addison County, Vermont. Vermont Family Forests places land health and water quality ahead of resource extraction, and community welfare ahead of maximum return on landowner investment.
Natural Democracy
Authors: Sayen Jamie
Published: May 2024

The Epilogue addresses the failure of contemporary democratic politics to reverse current trends in climate change, habitat degradation, and extinction crises. The author outlines a new approach to politics, modeled on wild nature, that acknowledges and abides by natural limits and the laws of nature—“Natural Democracy.” Poet Gary Lawless observes that healthy natural and human communities are conversations that include all voices. He adds that the planet is trying to educate us about appropriate ways of relating to nature. Elements of Natural Democracy include an informed electorate conversant in local, regional, and global natural history; a vote for all, including nonhumans and unborn generations; and land reform—a reclaiming of the wild commons. Plant and animal species may not be capable of casting a ballot, but they require much more preserved wild habitat and a low-carbon economy that does not degrade managed lands. Unborn generations are entitled to inherit an atmosphere with less than 350 ppm carbon dioxide. Achieving Natural Democracy requires humans to listen to what the land and its denizens are telling them.
A retrospective review of gram-negative spinal infections in a single tertiary spinal centre over six years
Authors: Tadross Daniel , McGrory Cieran , Greig Julia , Townsend Robert , Chiverton Neil , Highland Adrian , Breakwell Lee , Cole Ashley A.
Published: May 2024

Aims

Gram-negative infections are associated with comorbid patients, but outcomes are less well understood. This study reviewed diagnosis, management, and treatment for a cohort treated in a tertiary spinal centre.

Methods

A retrospective review was performed of all gram-negative spinal infections (n = 32; median age 71 years; interquartile range 60 to 78), excluding surgical site infections, at a single centre between 2015 to 2020 with two- to six-year follow-up. Information regarding organism identification, antibiotic regime, and treatment outcomes (including clinical, radiological, and biochemical) were collected from clinical notes.

Results

All patients had comorbidities and/or non-spinal procedures within the previous year. Most infections affected lumbar segments (20/32), with Escherichia coli the commonest organism (17/32). Causative organisms were identified by blood culture (23/32), biopsy/aspiration (7/32), or intraoperative samples (2/32). There were 56 different antibiotic regimes, with oral (PO) ciprofloxacin being the most prevalent (13/56; 17.6%). Multilevel, contiguous infections were common (8/32; 25%), usually resulting in bone destruction and collapse. Epidural collections were seen in 13/32 (40.6%). In total, five patients required surgery, three for neurological deterioration. Overall, 24 patients improved or recovered with a mean halving of CRP at 8.5 days (SD 6). At the time of review (two to six years post-diagnosis), 16 patients (50%) were deceased.

Conclusion

This is the largest published cohort of gram-negative spinal infections. In older patients with comorbidities and/or previous interventions in the last year, a high level of suspicion must be given to gram-negative infection with blood cultures and biopsy essential. Early organism identification permits targeted treatment and good initial clinical outcomes; however, mortality is 50% in this cohort at a mean of 4.2 years (2 to 6) after diagnosis.

Cite this article: Bone Jt Open 2024;5(5):435–443.
The #MeToo Movement in Iran: Reporting Sexual Violence and Harassment
Authors: Yaghoobi Claudia , Mincheva Dilyana , Hooman Niloofar , Hamidi Yalda , Rezai Yasamin , Moradian Manijeh
Published: May 2024

Abstract: Research and discussions concerning sexual harassment, rape, violence, and consent, among a myriad of other subjects, and their implications for women, men, as well as nonbinary and queer individuals in contemporary Iran, have been notably limited. However, with the emergence of Iran’s recent feminist movement, “Jin Jiyan Azadî” (Woman, Life, Freedom), in 2022, the edited volume titled The #MeToo Movement in Iran: Reporting Sexual Violence and Harassment (2023) has garnered heightened significance. This volume addresses the existing gap by amalgamating historical, sociological, and ethnographic research with an analysis of the contemporary discourse surrounding sexual harassment and the #MeToo movement within the framework of Iran’s religious, cultural, literary, and digital/globalized landscape. As the pioneering publication of its kind focusing on Iran’s #MeToo movement, this volume stands in solidarity with survivors and the tireless efforts of activists and journalists already engaged in this crucial work. Manijeh Moradian recently conducted interviews with the editor and select contributors to illuminate key aspects of the volume.
Anxiety and Community: Clune on Judgment
Authors: Lehman Robert S.
Published: May 2024

Abstract: In my response to Michael W. Clune’s A Defense of Judgment , I express some reservations about the notion of “community” that Clune invokes when he describes the sort of aesthetic judgment characteristic of a community of experts. More exactly, I ask whether a community focused on works of art and coming into being in a situation determined by modernism in the arts can ever cohere in quite the way that Clune needs it to, whether it can (or should even want to) attain the kind of sureness characteristic of, say, a scientific community.
Adaptive region algorithm based on a ternary optical computer
Authors: Song Kai , Hou Xinjun , Hu Huanyu , Wei Jingyang , Yan Liping
Published: May 2024

The adaptive region algorithm is an improved compression algorithm based on Huffman
coding. Because of the large number of rules for dividing regions in
the algorithm, there are problems such as high computing costs, slow
speed, and low compression efficiency. To address these problems, this
paper investigates the adaptive region algorithm based on a ternary
optical computer (TOC) combined with the characteristics of a ternary
optical computer, such as many data bits, high parallelism, and
three-valued coding. According to the characteristics of TOC
three-valued coding, this paper designs a three-valued character
coding scheme that can effectively shorten the coding length of
characters by changing the original coding rules and further improve
the compression efficiency of the adaptive region algorithm.
Furthermore, in conjunction with the advantages of TOC enabling
parallel computation, this paper presents an efficient computational
scheme capable of effectively improving computational efficiency
during the process of region partitioning. Through case studies, the
compression efficiency and computational efficiency of the adaptive
region algorithm implemented on TOC and an electronic computer were
analyzed, respectively. It was found that the compression efficiency
of the TOC-based algorithm is 50.4%, while that of the
electronic-computer-based algorithm is only 36%. In the comparison of
computational efficiency, the computational time complexity of TOC is O(n), whereas that of the electronic
computer (EC) is O(n2). Finally, it is concluded through
experimental validation that the TOC-based adaptive region compression
algorithm performs well in terms of computational performance and
compression efficiency, giving full play to the three-valued coding
characteristics of TOC-based as well as the advantages of being able
to realize parallel computation.
End-to-end optimization of optical communication systems based on directly modulated lasers
Authors: Hernandez Sergio , Peucheret Christophe , Da Ros Francesco , Zibar Darko
Published: May 2024

The use of directly modulated lasers (DMLs) is attractive in low-power, cost-constrained short-reach optical links. However, their limited modulation bandwidth can induce waveform distortion, undermining their data throughput. Traditional distortion mitigation techniques have relied mainly on the separate training of transmitter-side pre-distortion and receiver-side equalization. This approach overlooks the potential gains obtained by simultaneous optimization of the transmitter (constellation and pulse shaping) and receiver (equalization and symbol demapping). Moreover, in the context of DML operation, the choice of laser-driving configuration parameters such as the bias current and peak-to-peak modulation current has a significant impact on system performance. We propose, to our knowledge, a novel end-to-end optimization approach for DML systems, incorporating the learning of bias and peak-to-peak modulation current to the optimization of constellation points, pulse shaping, and equalization. The simulation of the DML dynamics is based on the use of the laser rate equations at symbol rates between 15 and 25 Gbaud. The resulting output sequences from the rate equations are used to build a differentiable data-driven model, simplifying the calculation of gradients needed for end-to-end optimization. The proposed end-to-end approach is compared to three additional benchmark approaches: the uncompensated system without equalization, a receiver-side finite impulse response equalization approach, and an end-to-end approach with learnable pulse shape and nonlinear Volterra equalization but fixed bias and peak-to-peak modulation current. The numerical simulations on the four approaches show that the joint optimization of bias, peak-to-peak current, constellation points, pulse shaping, and equalization outperforms all other approaches throughout the tested symbol rates.
Integrated 800 Gb/s O-band WDM optical transceiver enabled by hybrid InP-polymer photonic integration
Authors: Andrianopoulos Efstathios , Tokas Konstantinos , de Felipe David , Theurer Michael , Weigel Madeleine , Pagano Annachiara , Kanta Kostantina , Kresse Martin , Megas Giorgos , Tsokos Christos , Kouloumentas Christos , Chiadò Piat Anna , Tegegne Zerihun , Massaouti Maria , Bakopoulos Paraskevas , Moehrle Martin , Runge Patrick , Keil Norbert , Groumas Panos , Avramopoulos Hercules
Published: May 2024

We propose and demonstrate a novel O-band wavelength division multiplexing (WDM) optical transceiver enabled by the hybrid photonic integration of indium phosphide (InP) components into a polymer-based photonic motherboard called PolyBoard. The optical engine hosts an eight-fold InP electro-absorption modulated laser (EML) array at the transmitter part exhibiting >35GHz electro-optical bandwidth and an eight-fold InP photodiode (PD) array at the receiver part with 50 GHz bandwidth, butt-end coupled to the PolyBoard motherboard, which accommodates passive arrayed waveguide gratings (AWGs) at the transmitter and receiver sides, responsible for performing the wavelength multiplexing and demultiplexing functionalities, respectively. What we believe to be a novel thin-film-based O-band half-wave plate is placed at the receiver side AWG, ensuring the polarization insensitivity of the prototype. The optical engine’s design is discussed in the manuscript, demonstrating experimental results from its static and dynamic evaluation. Individual characterization of the transmitter and receiver sides of the optical engine is presented before evaluating the optical engine as a whole in a loopback configuration. The obtained results underscore the potential of the proposed hybrid photonic integrated transceiver for supporting 800 Gb/s capacity in intra-datacenter optical interconnects for transmission distances up to 2 km.
Fabrication of high power 1.5 µm wavelength InGaAsP/InP BH lasers having dilute waveguide structure
Authors: Guo Jing , Li Huan , Xiong Xinkai , Zhou Daibing , Zhao Linhgjuan , Liang Song
Published: May 2024

1.5 µm wavelength high power buried heterojunction (BH) semiconductor lasers having dilute waveguide structure have been fabricated. The optical field is dragged down toward the n side of the device by the dilute waveguide layer, lowering the optical confinement factor of the p doped material and active material, which helps to enlarge the laser output light power. Compared with thick InGaAsP cladding layer, the dilute waveguide material is easy to be grown and has higher thermal conductivity. The slope efficiency of the obtained dilute waveguide BH lasers is notably higher than that of the BH lasers having no dilute waveguide. Our studies show that the dilute waveguide structure is promising for the fabrication of high power BH lasers.
On the accuracy bounds of high-order image correlation spectroscopy
Authors: Katoozi Delaram , Clayton Andrew H. A. , Moss David J. , Chon James W. M.
Published: May 2024

High-order image correlation spectroscopy (HICS) or related image-based cumulant analysis of emitter species are important for identifying properties and concentrations of biomolecules or nanoparticles. However, lack of a thorough parameter space test limits its use in full potential. The current study focused on mapping accuracy bounds of bimodal species concentration space by simulating and analysing more than 2 × 105 images (∼1011 data points). Concentration space maps for four values of quantum yield contrast ratio between two species in a mixture and two sampling spaces (834 and 13357 beam areas in an image) were created, which showed clear accuracy bounds governed by two factors, Poisson fluctuation and quantum yield ratio. Typically, brighter species concentration was 1-3 orders of magnitude lower than that of dimmer species, and higher brightness contrast allowed higher concentration difference. Upper limit of accuracy bounds was governed by resolvable Poisson fluctuation, where this condition was violated for emitter density beyond 10 particles per beam area. The accuracy bounds are shown to be largely invariant under noise correction or the calculation method, and are compared against previous experimental results, showing consistent agreement. This study shows that concentration limit needs to be observed when using HICS or related image moment or cumulant analysis techniques. As a rule of thumb, a large quantum yield contrast and large sampling points allow more concentration difference between two species to be resolved in an analysis.
Surface roughness and wave slope statistics from the multi-spectral polarimetric imaging of the ocean surface
Authors: Malinowski Mateusz , Gilerson Alexander , Herrera-Estrella Eder , Foster Robert , Agagliate Jacopo , Ondrusek Michael
Published: May 2024

The polarization of light in Ocean Color (OC) applications provides important information about atmospheric parameters, water composition, and the ocean surface. The Stokes vector components and the degree of linear polarization of light contain useful information about the air-water interface, including ocean surface roughness. We present polarimetric measurements and analysis of the ocean wave slopes at several bands. Data is acquired with a Teledyne DALSA camera, which uses a polarizer-on-chip focal plane of 1232 × 1028 super-pixels, where each pixel is made of four subpixels with 0-, 90-, 45- and 135-degrees orientation of polarization. We present a modified version of the Polarization Slope Sensing (PSS) technique [Zappa et al., 2008] for the non-contact detection of wave slopes and demonstrate a good performance of the updated algorithm in several conditions where the original technique was not applicable. Derived wave slopes are presented for various aquatic and atmospheric environments, including during VIIRS Cal/Val cruises and at a near-shore pier. The results are shown to be consistent with theoretical wave slope models.
Numerical simulation of deep ultraviolet LED, micro-LED, and nano-LED with different emission wavelengths based on FDTD
Authors: Jia Jiangxie , Ruan YuanDong , Gu Yuning , Zhang Zhihao , Zhang Shanduan , Guo Ruiqian , cui XuGao , Tian PengFei
Published: May 2024

The current low external quantum efficiency (EQE) of deep ultraviolet (DUV) LEDs and micro-LEDs is largely attributed to their low light extraction efficiency (LEE). To address this issue and increase the LEE of DUV devices, various strategies such as reducing size, modifying surface with nanostructures and roughening substrates have been proposed. While some studies have investigated the effects of nanopillar and size on DUV LED, there remains a lack of systematic research on the LEE enhancement mechanism across different wavelengths and sizes of DUV LEDs, micro-LEDs, and nano-LEDs. Therefore, in this study, we employed the numerical simulation method to explore the LEE, near-field intensity distribution, and far-field light intensity distribution from various angles for DUV LEDs, micro-LEDs, and nano-LEDs with wavelengths of 255 nm, 260 nm, and 275 nm, respectively. Our findings reveal a significant improvement in the LEE of DUV nano-LEDs and micro-LEDs, accompanied by reduced divergence angles. Moreover, we observe that longer wavelengths correspond to higher LEE values for devices with similar size. This enhancement in LEE is attributed to factors such as increased sidewall emission and reduced p-GaN absorption. Our investigation indicates that as the size of the DUV device decreases, the sidewall LEE for both transverse electric (TE) and transverse magnetic (TM) modes increases, with TM mode exhibiting a larger enhancement. This enhancement is mainly attributed to the reduction of total reflection within the DUV LEDs and micro-LEDs resulting from size reduction. Despite this, TE mode remains the main contributor to overall LEE. Additionally, our study reveals a reduction in p-GaN absorption of DUV light with decreasing device size, further contributing to the enhancement of LEE in DUV micro-LEDs and nano-LEDs. The increased LEE and reduced divergence angles of small-size DUV micro-LEDs and nano-LEDs not only promote lower power consumption but also enable easier optical system coupling. Consequently, these advancements have significant potential in optical wireless communication, charge management and high-precision lithography.
Light-induced transformation of all-inorganic mixed-halide perovskite nanoplatelets: ion migration and coalescence
Authors: Zhang Huichao , Qiu Sibin , Huang Bo , Li Shitong , Gao Xiumin , Zhuang Songlin
Published: May 2024

When exposed to light, the colloidal perovskite nanoplatelets (NPLs) in the film can fuse into larger grains, and this phenomenon was thought to be closely related to ion migration. However, the available CsPbBr3 NPLs are not conducive to directly distinguishing this hypothesis. Herein, we prepare mixed-halide perovskite CsPbBr2.7I0.3 NPLs by a ligand-assisted reprecipitation method and investigate the photoluminescence evolution of NPLs under laser irradiation. At a low-irradiation intensity, 4.5-monolayer NPLs exhibit blue-shifted photoluminescence peaks due to the migration of iodide ions. Under higher laser fluence, a new photoluminescence component appears in the long wavelength region after the spectral blue shift, which is attributed to the coalescence of NPLs according to transmission electron microscopy analysis. A similar spectral evolution is also observed in 8-monolayer NPLs, while only the spectral blue shift caused by ion migration is detected in cuboidal CsPbBr2.7I0.3 nanocrystals. The use of strong bonding ligands can inhibit the fusion process of the NPLs, but not to impede ion migration, suggesting that fusion requires ligand detachment rather than ion migration. Similar suppression effects can be achieved in a vacuum atmosphere. Moreover, we demonstrate that mixed-halide NPLs can be used to realize anti-counterfeiting applications with superior photosensitivity.
High-gain ultra-wideband bismuth-doped fiber amplifier operating in the O + E + S band
Authors: Zhai Ziwei , Sahu Jayanta K.
Published: May 2024

We present a double-pass bismuth (Bi)-doped fiber amplifier (BDFA) providing high-gain wideband amplification from 1330 to 1480 nm. A peak gain of 38 dB with 4.7 dB noise figure (NF) was obtained at 1420 nm for a −23 dBm input signal, with >20 dB gain from 1335 to 1475 nm. We achieved 30  and 21.5 dB peak gains with 122 nm (1341–1463 nm) and 140 nm (1333–1473 nm) 6 dB-gain bandwidth for −10 and 0 dBm input signal, respectively. For a 0 dBm signal, the power conversion efficiency (PCE) reached 23.7%, and the in-band optical-signal-to-noise ratio (OSNR) across the wideband BDFA was >44 dB. Also, the absorption and luminescence characteristics have been studied for different Bi-doped phosphosilicate fibers (BPSFs) fabricated in-house.
Near-visible topological edge states in a silicon nitride platform
Authors: Sharp David , Flower Christopher , Jalali Mehrabad Mahmoud , Manna Arnab , Rarick Hannah , Chen Rui , Hafezi Mohammad , Majumdar Arka
Published: May 2024

Demonstrations of topological photonics have so far largely been confined to infrared wavelengths where imaging technology and access to low-dimensional quantum materials are both limited. Here, we designed and fabricated silicon nitride ring-resonator arrays to demonstrate photonic topological edge states at ∼780 nm. We observed edge states corresponding to the integer quantum Hall Hamiltonian with topological protection against fabrication disorder. This demonstration extends the concept of topological edge states to the near-visible regime and paves the way for nonlinear and non-Hermitian topological photonics with the rich library of near-visible quantum emitters.
PAM4-Modulated 2-Micron Band for Enhanced Indoor Optical Communications: Experimental Evaluation
Authors: Yang Yatao , Cai Junfei , Song Yufeng , Wang Zhenhong , Wu weijie , Jianhua Ji
Published: May 2024

This research explores the application of PAM4 modulation to optical signals in the 2-micron wavelength band for indoor optical communication. Experiments conducted in a simulated atmospheric turbulence environment demonstrated a BER of 10-5 for the 2-μm laser carrier with PAM4, surpassing the forward error correction threshold. Power loss comparisons to a back-to-back setup showed minimal degradation under various turbulence levels, with losses of 1.80 dB, 1.91 dB, 2.09 dB, and 2.55 dB for non-turbulent, weak-turbulent, moderate-turbulent, and strong-turbulent conditions, respectively. The system's sensitivity was measured at -7.69 dBm, emphasizing its effectiveness in detecting low-power signals. OptiSystem simulations indicated that PAM4 necessitates a higher optical OSNR than NRZ, suggesting the necessity for sophisticated signal processing techniques for systems operating in the 2-μm band. The study's results contribute to the body of knowledge on high-bandwidth optical communication and suggest future research avenues aimed at enhancing system performance while maintaining cost-effectiveness.
Fabrication of a low-cost benchtop optical imager for quantum dot microarray-based stress biomarker detection
Authors: Zeilinger Carsten , Kishore Anusha , Varughese Arun Mathew , Roth Bernhard
Published: May 2024

We report on a simplified optical imager to detect the presence of a stress biomarker protein, namely the Heat shock protein 90 (Hsp90). The imager consists of two elements the optical unit and the sensor which is a custom-made biochip. Measurement is based on the masking of the streptavidin conjugated quantum dot’s (Sav-QDs) fluorescence when Hsp90 attaches to it via biotinylated antibodies (Ab). The masking effect was directly proportional to the Hsp90 concentration. The cost-efficient benchtop imager developed comprises a CMOS sensor, standard optical lenses, and a narrow bandpass filter for optically eliminating background fluorescence. This approach is promising for the realization of cheap, robust, and reliable point-of-care detection systems for various biomarker analysis.
High-dimensional quantum correlation measurements with an adaptively gated hybrid single-photon camera
Authors: Kundu Sanjukta , Szuniewicz Jerzy , Firlik Grzegorz , Krupinski-Ptaszek Alexander , Lapkiewicz Radek
Published: May 2024

Efficient measurement of high-dimensional quantum correlations,
especially spatial ones, is essential for quantum technologies. We
propose and demonstrate an adaptively gated hybrid intensified camera
(HIC) that combines the information from a high spatial resolution
sensor and a high temporal resolution detector, offering precise
control over the number of photons detected within each frame. The HIC
facilitates spatially resolved single-photon counting measurements. We
study the measurement of momentum correlations of photon pairs
generated in type-I spontaneous parametric downconversion with the HIC
and demonstrate the possibility of time-tagging the registered
photons. With a spatial resolution of multi-megapixels and nanosecond
temporal resolution, this system allows for the realization of
previously infeasible quantum optics experiments.
Integrated photonic fractional convolution accelerator
Authors: Zelaya Kevin , Miri Mohammed-Ali
Published: May 2024

An integrated photonic circuit architecture to perform a modified-convolution operation based on the discrete fractional Fourier transform (DFrFT) is introduced. This is accomplished by utilizing two nonuniformly coupled waveguide lattices with equally spaced eigenmode spectra, the lengths of which are chosen so that the DFrFT and its inverse operations are achieved. A programmable modulator array is interlaced so that the required fractional convolution operation is performed. Numerical simulations demonstrate that the proposed architecture can effectively perform smoothing and edge detection tasks even for noisy input signals, which is further verified by electromagnetic wave simulations. Notably, mild lattice defects do not jeopardize the architecture performance, showing its resilience to manufacturing errors.
High-performance and wavelength-transplantable on-chip Fourier transform spectrometer using MEMS in-plane reconfiguration
Authors: Chen Heng , Zhang Hui , Zhou Jing , Ma Chen , Huang Qian , Wang Hanxing , Ren Qinghua , Wang Nan , Lee Chengkuo , Ma Yiming
Published: May 2024

On-chip spectrometers with high compactness and portability enable new applications in scientific research and industrial development. Fourier transform (FT) spectrometers have the potential to realize a high signal-to-noise ratio. Here we propose and demonstrate a generalized design for high-performance on-chip FT spectrometers. The spectrometer is based on the dynamic in-plane reconfiguration of a waveguide coupler enabled by an integrated comb-drive actuator array. The electrostatic actuation intrinsically features ultra-low power consumption. The coupling gap is crucial to the spectral resolution. The in-plane reconfiguration surmounts the lithography accuracy limitation of the coupling gap, boosting the resolution to 0.2 nm for dual spectral spikes over a large bandwidth of 100 nm (1.5–1.6 μm) within a compact footprint of 75  μm×1000  μm. Meanwhile, the in-plane tuning range can be large enough for arbitrary wavelengths to ensure the effectiveness of spectrum reconstruction. As a result, the proposed spectrometer can be easily transplanted to other operation bands by simply scaling the structural parameters. As a proof-of-concept, a mid-infrared spectrometer is further demonstrated with a dual-spike reconstruction resolution of 1.5 nm and a bandwidth of 300 nm (4–4.3 μm).
Assessing the evolution of research topics in a biological field using plant science as an example
Authors: Shiu Shin-Han , Lehti-Shiu Melissa D.
Published: May 2024

Scientific advances due to conceptual or technological innovations can be revealed by examining how research topics have evolved. But such topical evolution is difficult to uncover and quantify because of the large body of literature and the need for expert knowledge in a wide range of areas in a field. Using plant biology as an example, we used machine learning and language models to classify plant science citations into topics representing interconnected, evolving subfields. The changes in prevalence of topical records over the last 50 years reflect shifts in major research trends and recent radiation of new topics, as well as turnover of model species and vastly different plant science research trajectories among countries. Our approaches readily summarize the topical diversity and evolution of a scientific field with hundreds of thousands of relevant papers, and they can be applied broadly to other fields.
Modeling oxygen transport in the brain: An efficient coarse-grid approach to capture perivascular gradients in the parenchyma
Authors: Pastor-Alonso David , Berg Maxime , Boyer Franck , Fomin-Thunemann Natalie , Quintard Michel , Davit Yohan , Lorthois Sylvie
Published: May 2024

Recent progresses in intravital imaging have enabled highly-resolved measurements of periarteriolar oxygen gradients (POGs) within the brain parenchyma. POGs are increasingly used as proxies to estimate the local baseline oxygen consumption, which is a hallmark of cell activity. However, the oxygen profile around a given arteriole arises from an interplay between oxygen consumption and delivery, not only by this arteriole but also by distant capillaries. Integrating such interactions across scales while accounting for the complex architecture of the microvascular network remains a challenge from a modelling perspective. This limits our ability to interpret the experimental oxygen maps and constitutes a key bottleneck toward the inverse determination of metabolic rates of oxygen.

We revisit the problem of parenchymal oxygen transport and metabolism and introduce a simple, conservative, accurate and scalable direct numerical method going beyond canonical Krogh-type models and their associated geometrical simplifications. We focus on a two-dimensional formulation, and introduce the concepts needed to combine an operator-splitting and a Green’s function approach. Oxygen concentration is decomposed into a slowly-varying contribution, discretized by Finite Volumes over a coarse cartesian grid, and a rapidly-varying contribution, approximated analytically in grid-cells surrounding each vessel.

Starting with simple test cases, we thoroughly analyze the resulting errors by comparison with highly-resolved simulations of the original transport problem, showing considerable improvement of the computational-cost/accuracy balance compared to previous work. We then demonstrate the model ability to flexibly generate synthetic data reproducing the spatial dynamics of oxygen in the brain parenchyma, with sub-grid resolution. Based on these synthetic data, we show that capillaries distant from the arteriole cannot be overlooked when interpreting POGs, thus reconciling recent measurements of POGs across cortical layers with the fundamental idea that variations of vascular density within the depth of the cortex may reveal underlying differences in neuronal organization and metabolic load.