bluuebunny/crossref_metadata_2025 huggingface dataset:
Potential for reducing urban emissions with Semarang City pedestrian paths
Authors: Azizah Kirana Prasetya , Setiadji Bagus Hario , Huboyo Haryono Setiyo , Wijaya Arief Satya
Published: January 2025

Semarang City, as one of the big cities in Indonesia, faces significant challenges related to greenhouse gas (GHG) emissions, most of which come from the transportation sector. These emissions contribute to climate change and the decline in air quality in the city. This study explores the potential for reducing GHG emissions through the development of pedestrian paths in Semarang. By analyzing transportation emission data and the coverage of existing pedestrian paths, this study assesses the effectiveness of pedestrian path development in reducing emissions and improving urban quality of life. The methodology used includes GHG emission analysis, assessment of the area and coverage of pedestrian paths, and emission reduction projection models based on user survey data. Currently, only around 20% of the total roads in Semarang City have been built for pedestrian paths. By expanding and improving the quality of pedestrian paths, the potential for reducing CO2 emissions can reach 11% of total transportation emissions. This study suggests further development of pedestrian paths by considering factors such as comfort, accessibility, and connectivity to public transportation. This development not only has the potential to reduce GHG emissions but also increasing the resilience of cities to global climate change.
Social transformation of winongo river bank people in managing domestic waste
Authors: Zunariyah Siti , Sunesti Yuyun , Demartoto Argyo
Published: January 2025

Social transformation in managing household waste is a collective commitment to reduce the impact of climate change and realize sustainable development goals. The article aims to explain the process of social transformation in managing domestic waste and the factors that affect it. The research location is in the Winongo riverbank area of Yogyakarta through a qualitative exploration approach. As a result, the social transformation process runs through the stages of capacity building, group empowerment, relational community development, and new cultural development. The four stages do not run linearly, but tend to be dynamic and adaptive. The capacity building stage is very important because it is related to the internalization of new values on waste and its implications for the environment and health. Social transformation occurs if economic and political empowerment capital can be built to form a new culture. The factors inhibiting the transformation process are changes in the formation of actors and gender bias in domestic waste management. It takes a reorientation of the institutional format based on social capital and innovation of household waste management strategies with economic and ecological value to reduce the impact of climate change.
Biodiversity enrichment in KHDTK Wanadipa forest based on agarwood plants (Auricularia malaccensis Lamk)
Authors: W Hidayat Jafron , Puryono KS Sri , Astuti Yayuk , Wibowo Pratama J.
Published: January 2025

Forests have enormous functions for life, unfortunately continue to experience a decline in quality. The condition of biodiversity also continues to be under pressure. On the other hand, Diponegoro University, Undip as a research university considers to prepare environmental concern instruments as educational forest. The aim of the research is to determine the biological richness of tree stands in Kawasan Hutan Dengan Tujuan Khusus (KHDTK). It is also to study the physical and chemical conditions, especially as a basis for vegetation enrichment with a valuable agarwood plants. The results of the study showed that the species that had great importance value in terms of seedlings and trees were
Dalbergia (72%),
Leucaena (44.109%) and
Cassia siamea (13.199%). These species have very high reproduction rates and adaptability, since enable to produce many seeds. Indigenous forest tree, especially teak, have low important value because they have illegal logged before. There was no agarwood species or relative species found here. The soil and terrain conditions for enrichment with agarwood, are very suitable, although the slope is not really ideal. Slopes related to erosion and lead to poor soil nutrition. Alignment of planting through intercropping farming has great prospects for farmer, especially in relation to ecological and economic benefits.
Design of enhanced broadband optical couplers for long-infrared quantum well infrared photodetectors
Authors: Liu Huipeng , Li Ning , Zhou Xiaohao
Published: January 2025

Quantum-well infrared photodetectors (QWIPs) have emerged as a promising technology for broadband detection, particularly used in highly uniform large area focal plane array (FPA) imaging systems. However, one of the main challenges for broadband QWIPs is to design broadband optical couplers. In this paper, we propose a broadband optical scheme suited for the long-wavelength infrared quantum-well (QW) active layers. Our design features a multiple-stairstep reflection grating, which operates as a resonant waveguide in conjunction with the semiconductor layers. Surface plasmon polariton and transverse magnetic waveguide modes are effectively excited and regulated to match the active region. Over 40% absorption efficiency of the quantum wells is achieved across the entire range from 9 to 12 μm. Moreover, the structure demonstrates excellent fabrication tolerance and can be well compatible with FPAs, which is favored for practical applications.
Design optimization of the podded propulsor considering pod housing drag and propulsion motor performance
Authors: Zhou Yuhang , Liu Chengjiang , Yan Yao , Chen Quan , Ke Wenliang
Published: January 2025

The podded propulsor (POD) offers advantages such as high efficiency, low noise, and space-saving by integrating the propulsion motor and propeller. This paper presents an optimization methodology that simultaneously improves motor performance and pod housing drag through numerical analysis. The interaction between the motor and pod housing was analyzed, with parametric modeling conducted for both. The Latin hypercube sampling method generated samples of the motor and pod housing for simulation, and radial basis function neural networks were used to create approximate models for the motor performance and pod housing drag. The fitting R2 of motor efficiency, motor power density, propeller hub drag, pod body drag, and pod strut drag of the approximate model reached 0.995, 0.978, 0.920, 0.972, and 0.999, respectively. Sensitivity analysis revealed that the stator outer diameter and fore taper angle are key factors influencing motor performance and drag, respectively. A genetic algorithm was used to optimize the POD with bi-objective and tri-objective focuses on minimizing drag, maximizing motor efficiency and power density. Pareto-optimal designs were validated through simulations. The results show that tri-objective optimization increased the overall efficiency by about 4.2% and enhanced motor power density by around 22%.
pyVPT2: Interoperable software for anharmonic vibrational frequency calculations
Authors: Nelson Philip M. , Sherrill C. David
Published: January 2025

We present pyVPT2, a program to perform second-order vibrational perturbation theory (VPT2) computations to obtain anharmonic vibrational frequencies. This program is written in Python and can utilize any of the several quantum chemistry programs that have been interfaced to the QCEngine project of the Molecular Sciences Software Institute (MolSSI). The requisite single point energy, gradient, or Hessian computations can be automatically performed in a distributed-parallel fashion by optionally using the MolSSI’s QCFractal software. With pyVPT2, VPT2 anharmonic frequencies can now be computed using quantum chemistry programs that lack their own VPT2 capabilities.
Gravitation as a statistical theory on the light cone
Authors: Isidro José M , Paganini Claudio F , Pesci Alessandro
Published: January 2025

In this paper, we will explore Padmanabhan’s mesoscopic, statistical approach to gravity (Padmanathan 2017 J. Phys.: Conf. Ser.
880 012008) with a twist. The general picture of his approach is that spacetime is made of large numbers of localized quantum degrees of freedom. Padmanabhan assumed that the degrees of freedom of a given quantum state of geometry contribute, after averaging over fluctuations, a vector degree of freedom for spacetime at a point. For null vectors, this can be regarded as corresponding to one single vector, i.e. a pure state, for the statistical ensemble on the light cone at every point. In the present paper, we consider instead the case where the states of the gravitational degrees of freedom are spread out and overlap, with only probabilistic information on which of them determines the actual spacetime at a point. In the continuum limit, this corresponds to a mixed state for the statistical ensemble on the light cone at every point. This change in assumptions leads to some interesting observations. When we define a statistical ensemble on the light cone, its variance ‘knows’ about the interior of the light cone. As an intriguing consequence, we find that the cosmological constant can be related to the variance over the light cone. With a mixed state, we can no longer derive the gravitational field equations from an entropy functional. Here, instead, we show that a naive implementation of the measure of a mixed state on the light cone in the variation principle leads to modified measure theories as the grand canonical ensemble and allows one to reframe unimodular gravity as the canonical ensemble of a statistical theory on the light cone.
Investigation of positron scattering from 2H-pyran, 4H-pyran, and pyrrole molecules
Authors: Sharma Snigdha , Gupta Dhanoj
Published: January 2025

The scattering cross-sections for positron-biomolecule interaction are an essential input for the Monte-Carlo simulation techniques. In the present work, we have reported the elastic integral, differential, momentum transfer, and total ionization cross-sections for scattering of positron from 2H-pyran, 4H-pyran, and pyrrole molecules. The single-center expansion (SCE) method is employed for the elastic scattering calculations and the binary-encounter-Bethe model for ionization. We have also reported the elastic integral and differential cross-sections for benzene and furan, which are structurally similar to the pyran isomers and pyrrole, respectively, and compared them with the experimental and theoretical data available in the literature to validate the efficacy of the SCE method and the codes used. A comparative analysis of the elastic cross-sections for the isomers: 2H-pyran and 4H-pyran, and the pyrrole molecule that is isoelectronic with furan is also presented.
Protein-based microlasers: continuous transition from whispering gallery mode to random lasing
Authors: Nguyen Tam Trong , Mai Hanh Hong , Do Tien Xuan , Giang Khoi Manh , Nguyen Toan Van , Nguyen Tien Van , Nguyen Thau Xuan , Le Tuan Duy , Le Hai Hoang , Ta Van Duong
Published: January 2025

Whispering gallery mode (WGM) and random biolasers are important for bio-integration and biosensing applications due to their biocompatibility. However, these two laser types typically require different fabrication techniques, and limited research has explored transitioning between them using the same fabrication process. In this work, we present a comprehensive investigation into the transition from WGM to random lasing in protein-based microsphere lasers. Through a dehydration method, we can fabricate dye-doped protein microspheres with diameters ranging from 20 to 150 µm. By varying the polystyrene (PS) particle concentration within these microspheres, we observed a continuous transition from WGM to random lasing under optical pumping, driven by enhanced light scattering as PS concentration increased. Key lasing parameters, including the lasing spectrum and lasing threshold versus laser size and PS concentration, were analyzed and compared. The results indicate that microsphere random lasers (RLs) exhibit shorter lasing wavelengths. Particularly, a 63 µm WGM laser has a central lasing wavelength at 630 nm, while a RL of similar size shows a peak wavelength at 590 nm, a 40 nm blue shift. The lasing threshold increases with smaller laser size and higher PS concentration, with WGM lasers requiring several µJ mm−2, potentially ten times lower than RLs. Our work opens the possibility of designing flexible, wavelength-tunable biological microlasers. Moreover, it provides an understanding of the distinct characteristics of WGM and random lasing, making a meaningful contribution to laser research.
High Q-factor mie lattice resonance generated from out-of-plane magnetic dipole in all-dielectric defected semi-cylinder metasurface array
Authors: Zhang Lei , Liang Kunlin , Sun Chengchen , Tu Shijuan , Fu Qin , Feng Shuai , Du Qingguo , Li Zhengying , Xu Fei
Published: January 2025

Due to the weak far-field radiation and strong local field enhancement properties of Mie lattice resonances(MLRs), a transmission resonance with a significantly high Q factor is achieved, which can be used in applications such as refractive index sensing, filtering, and nanolasing. In this paper, we design a semi-cylinder with a cuboid defect metasurface array working in the near-infrared, where a resonance with extremely narrow linewidth in transmission spectrum has been demonstrated at the wavelength of 870.9408 nm. The full width at half-maximum of the resonance is as narrow as 0.0032 nm with a corresponding Q factor of 272169. According to distributions of the electric field and displacement current, it is confirmed that the narrow linewidth resonance is generated by the MLR, which originates from the coupling between the out-of-plane magnetic dipole mode and Rayleigh Anomalous diffraction. It is further verified that the out-of-plane magnetic dipole mode is excited due to the induce defect in the semi-cylinder. When applied to refractive index sensing, a sensitivity of 333 nm RIU‒1 and a figure of merit of 104063

RIU

−
1

are numerically achieved simultaneously. Our study here provides a new approach for achieving resonances with high Q-factors for the required applications.
Experimental and theoretical advances in Cu2ZnSn(S,Se)4 solar cells
Authors: Rodriguez-Osorio K G , Andrade-Arvizu J A , Montoya De Los Santos I , Morán-Lázaro J P , Ojeda-Martinez M , Sánchez-Rodríguez F J , Sánchez-Hernández L A , Pérez L M , Laroze D , Chandrasekar P , Routray S , Courel Maykel
Published: January 2025

Cu2ZnSn(SSe)4 (CZTSSe) semiconductor is quite promising to solar cell applications, recently achieving a new record efficiency of 14.9%. Despite theoretical works have shown that efficiencies higher than 20% are possible in this technology, there are some critical points that should be carefully solved by the scientific community. In this review, it is presented a critical analysis on the state-of-the-art of Cu2ZnSn(SSe)4 solar cells. First, we summarize advantages and disadvantages of most used vacuum and non-vacuum thin film fabrication methods, followed by the most important results in solar cell fabrication along with key factors in performance improvement. Furthermore, the future experimental outlook is also analyzed with a particular focus on kesterite material engineering and its grading band-gap engineering. Likewise, the experimental state-of-the-art of CZTSSe device fabrication, a non-typical contribution of this work to the literature it is the presentation and discussion of most important theoretical results on solar cells. A particular attention is paid to results concerning numerical and analytical approaches for the study of Cu2ZnSn(SSe)4 solar cells. Finally, theoretical results concerning the potential use of nanostructured CZTSSe solar cells for achieving efficiencies higher than that of the Shockley–Queisser limit are presented and discussed.
Spherical tip-plasma resonance probe with an improved upper pressure limit for electron density measurements in low-density plasmas
Authors: Lee SangHo , Kim SiJun , Park InYong , Eom GeonWoong , Seo Byonghoon , Hur Min , Kang WooSeok , You ShinJae , Kim Dae-Woong
Published: January 2025

Plasma resonance probes (PRPs) are used for electron density measurements based on the observation of the plasma resonance (PR) negative peak frequency at the electron plasma frequency in the transmission microwave spectrum. The cylindrical tip-plasma resonance probe (CT-PRP), also known as the cutoff probe, is widely used due to its simple structure. A recent study indicated that increasing the sheath width around the CT-PRP tip resulted in the PR negative peak frequency deviating from the electron plasma frequency and acted as a source of lowering the upper operating pressure limit. This disturbance becomes significant in low-density plasmas (

<

10

10

 c

m

−
3

)

, where thicker sheaths are unavoidable. This study proposes a spherical tip-plasma resonance probe (ST-PRP) to reduce the sheath width effect via the use of a lower sheath impedance of its spherical tip structure. The improved upper operating pressure limit of the ST-PRP was investigated using a three-dimensional electromagnetic simulation model. The results showed that the ST-PRP extended the upper limit of operating pressure and reduced the sensitivity of the upper pressure limit for changes in sheath width greater than the CT-PRP. An experimental study in low electron density capacitively coupled plasma sources was conducted to compare the upper pressure limit between the ST-PRP and the CT-PRP. The results were consistent with the numerical simulation results. We believe that the proposed ST-PRP with an extended upper pressure limit can be a reliable tool for accurate plasma electron density measurements of low-density plasmas using PRPs.
PIC/Fluid simulations of the plasma expansion in a planar magnetic arch
Authors: Guaita M , Ahedo E , Merino M
Published: January 2025

Magnetic arches (MA) (i.e. the magnetic topology that emerges when placing two magnetic nozzles with opposite polarities side by side) are an attractive option for the clustering of multiple electrodeless plasma thrusters, as they are characterized by a zero magnetic dipole moment and thus allow a reduction of perturbing magnetic forces on the spacecraft. This work employs the hybrid code EP2PLUS to simulate and study the plasma expansion for such a magnetic topology in the planar limit. First, a reference simulation is used to analyze the leading physical mechanisms that govern the plume properties. Ions are thus found to be characterized by a double peaked velocity distribution function close to the symmetry plane, where the plasma beams emitted by the two thrusters merge, while the magnetic force acting on electrons is shown to shape both the lateral confinement of the plume, and the thrust profile provided. Second, a parametric sweep on the strength of the magnetic field shows that its influence on the propulsive properties and on the characteristics of the plume saturates for values of the Hall parameter larger than around 10. Beyond this value of the Hall parameter, only the in-plane electron currents are found to be particularly sensitive both to the magnetization levels and the boundary conditions employed, although they are also largely decoupled from the rest of plasma properties. Finally, background pressure effects were considered by including collisions with neutral atoms in the simulations, highlighting the relevance of neutral entrainment in the modification of the plume properties and in the propulsive performance of the MA.
Metal–semiconductor–metal photodiode fabricated with an AlGaN/AlN superlattice for UV light detection
Authors: Wang Tong-Wen , Sharma Mukta , Tsai Chia-Lung , Zhang Jin-Rong
Published: January 2025

We designed and fabricated a nonplanar metal–semiconductor–metal (MSM) ultraviolet photodetector (PD), incorporating a 30-pair Al0.5Ga0.5N/AlN superlattice (SL) absorption layer on GaN-on-sapphire templates. In contrast to conventional PDs featuring a 100 nm-thick Al0.25Ga0.75N epilayer, our proposed PDs with the higher Al content of Al0.5Ga0.5N/AlN SLs did not exhibit degradation in epiwafer quality. With the incorporation of Al0.5Ga0.5N/AlN SLs, proposed MSM PDs with a top Ti/Al-based metal stack and a bottom Ni/Au electrode configuration showcased an enhanced photoresponsivity of 1129.8 A W−1 at ‒5 V in comparison to unitary Al0.25Ga0.75N epilayer made PDs. Moreover, by utilizing the Al0.5Ga0.5N/AlN SL absorption layer, we achieved an increased light-to-dark current ratio, reaching 3.66 × 105 biasing at a ‒7 V. The improvement in PD’s output performance could be attributed to the low metal/semiconductor Schottky barrier and strong electric field intensity within the SL absorption layer as the Ti/Al-based metal stack was used as the top electrode (the bottom electrode is Ni/Au). Finally, a 3 dB cut-off frequency of ∼1.2 MHz is achieved by using a homemade LED-based optical link with the proposed MSM PDs as the optical receiver.
Indium doping effects on the structural, morphological and electrical properties of WO3 powder pellets
Authors: Khusayfan Najla M , Khanfar Hazem K , Alharbi Seham R
Published: January 2025

Tungsten oxide powders were doped with indium at weight percentages ranging from 5 to 15 wt% and pressed into pellet form under a pressure of 200 bars. The doping process was carried out using the solid-state reaction technique. The doped samples were sintered at 750 °C for 12 h. Both undoped and indium-doped powder pellets exhibited a triclinic structure, with hexagonal InxWO3 emerging as a minor phase that increased with higher indium content. Indium doping increased microstrain, the percentage of stacking faults, and defect concentration while decreasing the crystallite sizes in the WO3 powder pellets. Morphological analysis of the samples revealed irregular grain shapes and sizes within the pellets. Notably, indium doping significantly reduced the porosity of WO3 from 7.42% to 3.83% as the indium content increased to 15 wt%. Electrically, the n-type resistivity increased with higher doping levels, indicating deeper donor levels. Specifically, the donor states in the powder pellets increased from 0.21 eV to 0.27 eV as the indium content rose from 5 wt% to 10 wt%, and further reached 0.29 eV at 15 wt% indium. Moreover, AC signal analysis of the powder pellets demonstrated their potential as microwave resonators suitable for antenna applications. Indium doping effectively engineered the maximum cutoff frequency, with values reaching 80 GHz in WO3 pellets doped with 15 wt% indium. These powder pellets, with thicknesses not exceeding 700 μm and electrode areas of 3.14 × 10−2 cm2, show great promise for 5 G/6 G technology applications as concurrent quad-band antennas.
Modeling and simulation of the effect of surface roughness on the Fowler-Nordheim conduction in MOS structures
Authors: Meguellati S , Messai Z , Sarra M
Published: January 2025

A compact Fowler–Nordheim (FN) tunneling current model is derived to describe the non-ideal, surface roughness-related relationship between current and voltage in a metal-oxide-semiconductor (MOS) capacitors. This relationship is achieved by applying a fractal continuum Laplacian operator in the 1D Schrödinger equation, resulting in a model that extends the standard FN to account for surface inhomogeneities through a fractional power α. Our error analysis predicts significant inaccuracies in the extracted FN parameters when using the standard FN model to interpret rough surface data. A methodology for extracting FN fractal parameters and the flat band voltage via a fractal FN plot is proposed. Simulated datasets and real measurements of Al/SiO2/4H-SiC capacitors are used to validate the model. Comparison of the parameters extracted using the fractal FN model and the standard FN model confirms the predictions from the error analysis and the suitability of the fractal FN model. The fractal FN model offers a potential explanation for the large discrepancies observed in FN parameters reported in the literature.
Electron and positron impact ionization cross sections of SiF4
Authors: Song Yunliang , Ma Yuwei , Li Bowen , Chen Ximeng
Published: January 2025

Based on the Binary-Encounter-Bethe (BEB) model, we present comprehensive cross-sectional data on total ionization cross sections, partial cross sections, single differential cross sections, average secondary electron energy and stopping cross sections for the SiF4 molecule in the case of electron and positron impact. For the partial cross sections, we employ the mass spectrum data (MSD) method and Huber’s model. By comparing theoretical calculations with experimental measurements, we determine the fragmentation pattern of SiF4. For positron scattering, we utilize three methods known as BEB0, BEBA, and BEBW. There is limited data of electron impact available on SiF4, and there is a notable lack of relevant investigations regarding positron impact with SiF4. Our research continues the exploration of electron and positron impact cross sections for SiF4 and serves as a reference for future studies.
Exploring the impact of substituents on the photophysical properties of boron dipyrromethene dyes for enhanced photovoltaic performance
Authors: Cui Peng , Ling Zichao
Published: January 2025

Boron dipyrromethene (BODIPY) dyes are known for their strong fluorescence and excellent photostability, making them vital for various photoelectric applications. This study explores how different substituents affect the photophysical properties of BODIPY dyes to improve their performance in dye-sensitized solar cells (DSSCs). We examine six distinct BODIPY dye structures with unique electron-withdrawing (NO2, CHO, Br) and electron-donating (OCH3, NPh2) substituents, along with a hydrogen-substituted variant, and report key photovoltaic parameters, including open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and energy conversion efficiency (Ω). Using density functional theory (DFT) and time-dependent DFT (TD-DFT), we analyze the dyes’ light-harvesting efficiency, electron injection efficiency, and overall energy conversion efficiency. Our results indicate that electron-donating groups, especially NPh2 and OCH3, significantly enhance Voc, Jsc, FF, and Ω, leading to improved energy conversion efficiencies. In contrast, while electron-withdrawing substituents increase chemical stability, they typically result in lower photovoltaic performance. This research underscores the importance of strategic substituent selection in optimizing BODIPY dyes for enhanced photoelectric performance, offering valuable insights for designing efficient photovoltaic materials.
Investigation on flux design & their effect on the mechanical properties of the SAW of Duplex Stainless Steel-2205
Authors: Gupta Deepak , Bansal Amit , Jindal Sandeep
Published: January 2025

The SAW fluxes for Duplex Stainless Steel (DSS)-2205 are not easily available. Generally, the available flux configuration is suitable for different grades of stainless steel but not suitable for the DSS. The current research aims to formulate the flux for DSS-2205 by varying the different flux ingredients and to investigate the impact of linear flux ingredients and their binary mixture effect on the mechanical characteristics of the butt joining of DSS-2205. The technique of extreme vertices design suggested by McLean and Anderson is employed to develop twenty-one fluxes. The effect of twenty-one flux ingredients was analyzed on the fabricated weldment’s characteristics such as ultimate tensile strength (UTS), percentage elongation, impact strength, and microhardness. In this research, a mathematical model has been developed for UTS, percentage elongation, impact strength and microhardness of weld specimens in terms of the flux ingredients. It is found from the experiments that the tensile strength and percentage elongation of weldments is increased by the flux ingredients such as silica (SiO2) and magnesium-oxide (MgO), while the alumina (Al2O3) and calcium fluoride (CaF2) has decreasing effect on UTS. Impact strength is found to be decreased by the linear effect of Al2O3. Excluding CaF2, all the linear flux ingredients have an increasing effect on the microhardness of the weld metal. Increased binary effect of Al2O3.CaF2, Al2O3.MgO, and MgO.CaF2 flux ingredients are found on the UTS, percentage elongation, impact strength and microhardness of the weldment. For the adequacy of the developed regression model, analysis of variance (F-statistics) is used for all the regression equations.
Quantum teleportation of incomplete multi-quantum systems
Authors: Wu Yingqi , Jin Yuanfeng , Liu Yang , Lyu Gang
Published: January 2025

This paper proposes a quantum teleportation scheme for incomplete multi-quantum systems. According to the structure of the transport state, the number and structure of the quantum channel can be determined, as well as the quantum circuit for quantum teleportation. Compared to previous quantum teleportation protocols, this scheme reduces both the number of qubits in the channel and the amount of classical communication required, thereby enhancing the efficiency of quantum teleportation. Furthermore, this approach offers a new path for constructing non-maximally entangled state channels, which is beneficial for building complex quantum networks and enabling Multi-party quantum teleportation.
Personalized µ-transcranial alternating current stimulation improves online brain–computer interface control
Authors: H Liu Deland , Kumar Satyam , Alawieh Hussein , Samuel Racz Frigyes , del R Millán José
Published: January 2025

Objective. A motor imagery (MI)-based brain–computer interface (BCI) enables users to engage with external environments by capturing and decoding electroencephalography (EEG) signals associated with the imagined movement of specific limbs. Despite significant advancements in BCI technologies over the past 40 years, a notable challenge remains: many users lack BCI proficiency, unable to produce sufficiently distinct and reliable MI brain patterns, hence leading to low classification rates in their BCIs. The objective of this study is to enhance the online performance of MI-BCIs in a personalized, biomarker-driven approach using transcranial alternating current stimulation (tACS). Approach. Previous studies have identified that the peak power spectral density value in sensorimotor idling rhythms is a neural correlate of participants’ upper limb MI-BCI performances. In this active-controlled, single-blind study, we applied 20 min of tACS at the participant-specific, peak µ frequency in resting-state sensorimotor rhythms (SMRs), with the goal of enhancing resting-state µ SMRs. Main results. After tACS, we observed significant improvements in event-related desynchronizations (ERDs) of µ SMRs, and in the performance of an online MI-BCI that decodes left versus right hand commands in healthy participants (N = 10)—but not in an active control-stimulation control group (N = 10). Lastly, we showed a significant correlation between the resting-state µ SMRs and µ ERD, offering a mechanistic interpretation behind the observed changes in online BCI performances. Significance. Our research lays the groundwork for future non-invasive interventions designed to enhance BCI performances, thereby improving the independence and interactions of individuals who rely on these systems.
Unsupervised, piecewise linear decoding enables an accurate prediction of muscle activity in a multi-task brain computer interface
Authors: Ma Xuan , Rizzoglio Fabio , Bodkin Kevin L , Miller Lee E
Published: January 2025

Objective. Creating an intracortical brain-computer interface (iBCI) capable of seamless transitions between tasks and contexts would greatly enhance user experience. However, the nonlinearity in neural activity presents challenges to computing a global iBCI decoder. We aimed to develop a method that differs from a globally optimized decoder to address this issue. Approach. We devised an unsupervised approach that relies on the structure of a low-dimensional neural manifold to implement a piecewise linear decoder. We created a distinctive dataset in which monkeys performed a diverse set of tasks, some trained, others innate, while we recorded neural signals from the motor cortex (M1) and electromyographs (EMGs) from upper limb muscles. We used both linear and nonlinear dimensionality reduction techniques to discover neural manifolds and applied unsupervised algorithms to identify clusters within those spaces. Finally, we fit a linear decoder of EMG for each cluster. A specific decoder was activated corresponding to the cluster each new neural data point belonged to. Main results. We found clusters in the neural manifolds corresponding with the different tasks or task sub-phases. The performance of piecewise decoding improved as the number of clusters increased and plateaued gradually. With only two clusters it already outperformed a global linear decoder, and unexpectedly, it outperformed even a global recurrent neural network (RNN) decoder with 10-12 clusters. Significance. This study introduced a computationally lightweight solution for creating iBCI decoders that can function effectively across a broad range of tasks. EMG decoding is particularly challenging, as muscle activity is used, under varying contexts, to control interaction forces and limb stiffness, as well as motion. The results suggest that a piecewise linear decoder can provide a good approximation to the nonlinearity between neural activity and motor outputs, a result of our increased understanding of the structure of neural manifolds in motor cortex.
Recent progress in two-dimensional polymer materials: interfacial synthesis and applications
Authors: Ma Lili , Hou Wenbo , Li Anbai , Peng Hui , Xie Xuan , Ma Guofu , Xu Yuxi
Published: January 2025

As a new two-dimensional polymer (2DP) synthetic material, 2DPs not only have the advantages of high specific surface area and high transparency of 2D materials, but also have the advantages of high mechanical strength and easy processing of polymer materials. Therefore, 2DPs are widely used and have become one of the indispensable materials today. However, there are still challenges in preparing 2DPs using traditional methods. Among the various synthesis strategies, the interfacial synthesis methods with the advantages of simple operation and high crystallinity have become typical method for preparing 2DPs. In this review, we first summarize the types of interface synthesis methods and the latest research progress. Secondly, the 2DPs applications in optoelectronic devices, membrane separation, sensor, electrical device and batteries, etc. are introduced. Finally, we summarize and prospect the existing challenges and future research directions based on the current research status of 2DPs.
Continuous-variable quantum key distribution with noisy squeezed states
Authors: Oruganti Akash nag , Derkach Ivan , Filip Radim , Usenko Vladyslav C
Published: January 2025

We address the crucial role of noisy squeezing in security and performance of continuous-variable (CV) quantum key distribution (QKD) protocols. Squeezing has long been recognized for its numerous advantages in CV QKD, such as enhanced robustness against channel noise and loss, and improved secret key rates. However, the excess noise of the squeezed states, that unavoidably originates already from optical loss as well as other imperfections in the source, raises concerns about its potential exploitation by an eavesdropper. For the widely adopted trust assumption on the excess noise in the signal states, we confirm the stability of the protocol against the noisy squeezing in both purely attenuating as well as noisy channels in the asymptotic limit, which implies perfect parameter estimation. In the finite-size regime we show that this stability largely holds at up to 107 data points using optimal biased homodyne detection for key distribution and parameter estimation. Untrusted assumption on the noisy squeezing, on the other hand, introduces additional security bounds on the squeezing excess noise already in the asymptotic regime, which is further enforced by the finite-size effects. Additionally, we show the critical negative role of noisy squeezing in the case of atmospheric free-space channels, already in the trusted-noise and asymptotic assumptions, which emphasizes the importance of squeezing purity in the free-space quantum channels. Our results pave the way towards practical realization of squeezed-state CV QKD protocols in both fibre and free-space channels.
Analysis of noise characteristics of ceramic bearings rotor system in a wide temperature range
Authors: An Wenjie , Gu Yanling , Chen Changzheng , Zheng Hao , Tian Miao
Published: January 2025

The loosening effect of ceramic bearings in steel seats becomes increasingly pronounced over a wide temperature range as the temperature rises. This leads to more complex bearing movements and more intense contact with the inner walls of the steel seats, significantly impacting the system’s noise characteristics. In the noise model of the ceramic bearing rotor system, the shaft was discretized into elements, and the variable clearance between the bearing and the steel seat due to temperature changes was used as the geometric boundary condition for the outer ring motion. The influence of temperature and clearance on the noise characteristics of ceramic bearings was investigated experimentally. The results indicate that the clearance, by altering the interaction between the bearing and the steel housing, affects the system’s sound radiation. Sound pressure level was positively correlated with temperature increase, and the directionality of the noise also varied with temperature. Following manufacturing requirements, connecting ceramic bearings to the steel housing through an interference fit can effectively mitigate the noise from ceramic bearings. These research findings provide theoretical guidance for the installation and noise suppression of ceramic-bearing rotor systems across a wide temperature range.
Causality-driven feature selection and domain adaptation for enhancing chemical foundation models in downstream tasks
Authors: Soares Eduardo , Shirasuna Victor Yukio , Brazil Emilio Vital , Aquino Gutierrez Karen Fiorella , Cerqueira Renato , Zubarev Dmitry , Schmidt Kristin , Sanders Daniel P
Published: January 2025

Recent advancements in large foundation models have revealed impressive capabilities in mastering complex chemical language representations. These models undergo a task-agnostic learning phase, characterized by pre-training on extensive unlabeled corpora followed by fine-tuning on specific downstream tasks. This methodology reduces reliance on labeled data, facilitating data acquisition and broadening the scope of chemical language representation. However, real-world scenarios often pose challenges due to domain shift, a phenomenon where the data distribution in downstream tasks differs from that of the pre-training phase, potentially degrading model performance. To address this, we present a novel causal-based framework for feature selection and domain adaptation to enhance the performance of chemical foundation models on downstream tasks. Our approach employs a multi-stage feature selection method that identifies physico-chemical features based on their direct causal-effect over specific downstream properties. By employing Mordred descriptors and Markov blanket causal graphs, our approach provides insight into the causal relationships between features and target properties for prediction tasks. We evaluate our approach on various foundation model architectures and datasets, demonstrating performance improvements, which showcases the robustness and the agnostic nature of our approach.
Co-occurring climate events and environmental justice in California, 2018–2019
Authors: Shea Brittany , Meltzer Gabriella Y , Steiger Benjamin B , Parks Robbie M , Do Vivian , McBrien Heather , Flores Nina , Gordon Milo , Blake Elizabeth M , Casey Joan A
Published: January 2025

Climate change will increase the frequency of extreme weather events. This means climate-driven events like wildfires and power outages will likely co-occur more often, potentially magnifying their health risks. We characterized three types of climate-driven events—anomalously warm temperatures, wildfire burn zone disasters, and long power outages—in 58 California counties during 2018–2019. We defined county-day anomalously warm temperatures when daily average temperatures exceeded 24 °C and the 85th percentile of the long-term county average. We defined county-day wildfire burn zone disasters when an active wildfire burn zone intersected a county, burned 1+ structures, killed a civilian, or received a Federal Emergency Management Agency Fire Management Declaration, and overlapped with a community. For a subset of the 38 counties (66%), long power outage county days were identified using PowerOutage.us data when an outage affected >0.5% of county customers for 8+ h. Co-occurring events were when 2+ of these events occurred on the same county day. Using the CDC/ATSDR Social Vulnerability Index (SVI), we determined whether co-occurring events disproportionately affected vulnerable populations. Nearly every county (97%) experienced at least one day of anomalously warm temperatures, 57% had at least one wildfire burn zone disaster day, and 63% (24/38 counties with available data) had at least one long power outage day. The most common co-occurring events (anomalously warm temperatures and wildfire burn zone disasters) impacted 24 (41%) counties for 144 total county-days. We did not find a clear connection between co-occurring events and social vulnerability. We observed an inverse correlation between co-occurring wildfire burn zone disasters and long power outage days with SVI, and a positive correlation between co-occurring anomalously warm and long power outage days with SVI. This analysis can inform regional resource allocation and other state-wide planning and policy objectives to reduce the adverse effects of climate-driven events.
To bob or not to bob: context-dependence of an antipredator response in neotropical harvestmen
Authors: Calhoun Austin C , Tobin Kerrigan B , Poorboy Dylan M , Bowden Rachel M , Sadd Ben M
Published: January 2025

Inducible defence strategies evolve in response to temporally and spatially variable predation risk. Selection should favor the expression of these strategies when risk crosses a threshold, but expression may also depend on how effective a strategy is across contexts. For neotropical harvestmen, aggregation behavior is a group-level defence strategy but can be supplemented by additional behavior to enhance antipredator defence. A secondary behavioral strategy termed “bobbing,” in which individuals rapidly move their bodies up and down, has been proposed to confuse or deter predation as the group moves en masse. While this behavior may be performed in isolation, we propose that its net pay-off may depend on the presence of conspecifics and group size. Therefore, due to the benefits of plasticity in a behavior with such an apparent context dependent pay-off, we hypothesize that the aggregation size of neotropical harvestmen affects the propensity of individuals to engage in the antipredator bobbing defence. We predicted that individuals would be more likely to perform bobbing in aggregations as opposed to in isolation. We collected harvestmen (Prionostemma sp.) at La Selva Biological Research Station, Costa Rica, and exposed them to a simulated predator cue when housed within experimental chambers. Individuals were more likely to engage in bobbing when in a group than alone. Moreover, we performed field observations that found bobbing to be a more frequent response as group size increased. Our results show social context-dependence of an inducible antipredator defence behavior that aligns with proposed costs and benefits of its expression.
Collagen turnover during cervical remodeling involves both intracellular and extracellular collagen degradation pathways
Authors: Colon-Caraballo Mariano , Russell Serena R , Myers Kristin M , Mahendroo Mala
Published: January 2025

Reproductive success requires accurately timed remodeling of the cervix to orchestrate the maintenance of pregnancy, the process of labor, and birth. Prior work in mice established that a combination of continuous turnover of fibrillar collagen and reduced formation of collagen cross-links allows for the gradual increase in tissue compliance and delivery of the fetus during labor. However, the mechanism for continuous collagen degradation to ensure turnover during cervical remodeling is still unknown. This study demonstrates the functional role of extracellular and intracellular collagen degradative pathways in two different settings of cervical remodeling: physiological term remodeling and inflammation-mediated premature remodeling. Extracellular collagen degradation is achieved by the activity of fibroblast-derived matrix metalloproteases MMP14, MMP2, and fibroblast activation protein (FAP). In parallel, we demonstrate the function of an intracellular collagen degradative pathway in fibroblast cells mediated by the collagen endocytic mannose receptor type-2 (MRC2). These pathways appear to be functionally redundant as loss of MRC2 does not obstruct collagen turnover or cervical function in pregnancy. While both extracellular and intracellular pathways are also utilized in inflammation-mediated premature cervical remodeling, the extracellular collagen degradation pathway uniquely employs fibroblast and immune-cell-derived proteases. In sum, these findings identify the dual utilization of two distinct degradative pathways as a failsafe mechanism to achieve continuous collagen turnover in the cervix, thereby allowing dynamic shifts in cervical tissue mechanics and function.
Phylogenomics and intergenomic conflict in a challenging orchid clade (Calypsoinae): monophyly of Corallorhiza, paraphyly of Oreorchis, and resurrection of Kitigorchis
Authors: Barrett Craig F , Freudenstein John V , Skibicki Samuel V , Sinn Brandon T , Chung Shih-Wen , Hsu Tian-Chuan , Liao Wenbo , Lee Shiou Yih , Luo Yi-Bo , Yukawa Tomohisa , Suetsugu Kenji
Published: January 2025

Heterotrophic plants are among the most recalcitrant from a systematics perspective because of reduced morphological and genomic features, and often extreme substitution rate heterogeneity. The orchid subtribe Calypsoinae exemplifies this, containing several lineages that have lost leaves and photosynthesis. In particular, relationships of the leafy Asian Oreorchis and the leafless American Corallorhiza have been contentious. Here we used nuclear sequence capture to resolve relationships within Calypsoinae and addressed the monophyly of Corallorhiza and Oreorchis, for which previous studies have highlighted conflicting patterns of monophyly or paraphyly, depending on the data analysed. Nuclear analyses provided strong support for a monophyletic Corallorhiza and paraphyletic Oreorchis, the latter with two strongly supported clades. As in previous studies, plastid analyses recovered strongly supported paraphyletic assemblages for both genera. Topology tests using plastid and nuclear relationships and data rejected the constrained topologies, further revealing strong cytonuclear conflict. Network-based analyses revealed a lack of evidence for hybridization, suggesting incomplete lineage sorting associated with biological and historical factors have driven intergenomic conflict. Additionally, we found that loci identified as putatively lost in holomycotrophic Corallorhiza species are functionally enriched for organellar functions. The study provides a strong case for the resurrection of Kitigorchis as the sister of Corallorhiza, with two species, Kitigorchis erythrochrysea and Kitigorchis indica, and highlights the challenges associated with phylogenetics of lineages containing mycoheterotrophs.