bluuebunny/crossref_metadata_2025 huggingface dataset:
On-demand reversible switching of the emission mode of individual semiconductor quantum emitters using plasmonic metasurfaces
Authors: Olejniczak Adam , Lawera Zuzanna , Zapata-Herrera Mario , Chuvilin Andrey , Samokhvalov Pavel , Nabiev Igor , Grzelczak Marek , Rakovich Yury , Krivenkov Victor
Published: January 2024

The field of quantum technology has been rapidly expanding in the past decades, yielding numerous applications, such as quantum information, quantum communication, and quantum cybersecurity. At the core of these applications lies the quantum emitter (QE), a precisely controllable generator of either single photons or photon pairs. Semiconductor QEs, such as perovskite nanocrystals and semiconductor quantum dots, have shown much promise as emitters of pure single photons, with the potential for generating photon pairs when hybridized with plasmonic nanocavities. In this study, we have developed a system in which individual quantum emitters and their ensembles can be traced before, during, and after the interaction with an external plasmonic metasurface in a controllable way. Upon coupling the external plasmonic metasurface to the QE array, the individual QEs switch from the single-photon emission mode to the multiphoton emission mode. Remarkably, this method preserves the chemical structure and composition of the QEs, allowing them to revert to their initial state after decoupling from the plasmonic metasurface. This significantly expands the potential applications of semiconductor QEs in quantum technologies.
Numerical investigation on non-linear streaming effects in a two-stage coaxial pulse tube cryocooler
Authors: C Damu , Moudghalya Sumukh , Nerale Mrunal M. , Panda Debashis , K S Rajendra Prasad , Behera Upendra , Reddy B. N. Sathyanarantana
Published: January 2024

Stirling pulse tube cryocoolers (PTC) are widely used in aerospace applications for the cooling of infrared sensors and for filtering background thermal noise in the astro-imaging devices, etc. Present investigation aims to use numerical methods to demonstrate the nonlinear fluid flow, heat transfer, and vortex generation phenomena in a two-stage coaxial type inertance pulse tube cryocooler. The numerical simulation is conducted using commercially available Fluent® code for both single-stage and multi-stage configurations to show nonlinear processes with varying heat load conditions. It has been noticed that the width of the vortex produced inside the pulse tube grows with an increase in heat load capacity. This undesirable flow conditions yields an adverse effect in the cooling behavior and reduces overall performance of cryocooler with higher heat load. Additionally, streamlines, stream function, pressure and temperature variation plots are given for both stages with different heat load capacity to substantiate our results.
Measurements of flow-induced vibration of a flexible splitter plate mounted on a cylinder in free stream flow
Authors: Giri Shubham , Kartik V. , Agrawal Amit , Bhardwaj Rajneesh
Published: January 2024

We experimentally study flow-induced vibration (FIV) of a thin, cantilevered, flexible plate attached on the lee side of a circular cylinder in a free stream airflow. The Reynolds number (ReD) based on the diameter of the cylinder was varied in the range of (4 × 103, 5×104). The plates of different lengths and the same span were tested with varying airflow velocities (U) in a wind tunnel. The reduced velocity (UR) based on the length and the second natural frequency of the plate was in the range of (1, 11). We describe the plate dynamics showing displacement, frequency, phase plane, amplitude spectral density (ASD), oscillation envelope, modal energy contribution, and flow structures. Based on the motion of the plate, three FIV regimes are observed, namely, initial excitation, transition, and lock-in. During lock-in, the plate attains self-sustained limit cycle oscillation. We observe the presence of small-amplitude higher harmonics in the ASD plot. The second mode is dominant around the onset of lock-in, while the first mode is dominant later in the lock-in regime. The dimensionless displacement increases with an increase in mass ratio (Ms) in the lock-in regime. With a decrease in Ms, the slope of the dimensionless frequency with UR increases. To explain measurements, we develop a wake oscillator model (WOM) in which the plate and fluctuating lift force are modeled as an Euler–Bernoulli cantilever beam and van der Pol oscillator, respectively. The coupled WOM qualitatively and quantitatively predict the measured amplitude and frequency response, respectively, in the lock-in regime.
Terahertz spectroscopy of MOFs reveals dynamic structure and contact free ultrafast photoconductivity
Authors: Hamilton Kendra , Neu Jens
Published: January 2024

Metal-organic frameworks (MOFs) are porous crystalline materials. Their large pores make them particularly interesting for membranes, gas separation, and gas storage. Furthermore, MOFs are ultralight, making them suitable for a large realm of exciting applications ranging from wearable devices to space technology. Optimizing MOFs for these applications demands a detailed understanding of their low energy dynamics and photophysics, which can be provided by terahertz (THz) spectroscopy. MOFs exhibit structural modes, or phonons, with energies in the meV range, which corresponds to the THz spectral range (0.1–10 THz, 0.4–40 meV). Understanding these modes is crucial in determining how a MOF interacts with guest molecules in the process of gas capture and storage. In this perspective, we discuss how gas-MOF interactions alter the MOFs’ spectral fingerprints. We demonstrate that THz spectroscopy can be used for gas adsorption monitoring and explain how density functional theory, together with THz spectra, can illuminate the dynamic structure of MOFs, providing unique insight into their functionality. THz is also a contact free probe for conductivity and allows us to measure short range conductivity within an individual MOF crystal. We will discuss the advantages of THz as a conductivity probe for MOFs as compared to more established direct current techniques. We will then expand our view to incorporate ultrafast photoconductivity in MOFs measured via optical pump-THz probe spectroscopy, in comparison to more established ultrafast spectroscopic tools such as optical transient absorption and photoluminescence. We will supplement this section with a discussion of THz studies on perovskites, which unveiled electron–phonon interactions not yet explored in MOFs.
Room-temperature NH3 gas sensing of S-hyperdoped silicon: Optimization through substrate resistivity
Authors: Li Yuan , Li Hua , Feng Guojin , Wang Wenjing , Dong Binbin , Zhao Li , Zhuang Jun
Published: January 2024

Sulfur-hyperdoped black silicon (S-BSi) prepared by femtosecond laser-assisted etching in SF6 atmosphere has dual characteristics of large specific surface area and super-doped impurities, and its physics and applications have attracted extensive attention. The room-temperature NH3 gas sensing capability of the samples is studied in the conductance mode. The S-BSi-based sensors exhibit a response to NH3 gas. Interestingly, their responsivity varies with the substrate resistance, and the sensor based on an appropriate substrate resistance shows the optimal responsivity. Additionally, the device demonstrates fast response and recovery speed, as well as good selectivity. The evolution of the responsivity and response/recovery time is recorded with natural aging for two months, showing acceptable long-term durability. The mechanism by which the responsivity of S-BSi-based sensors varies with resistivity is discussed. Based on this mechanism, there is an optimal substrate resistivity that maximizes the responsivity. The results show that S-BSi is a potential material for the fabrication of conductivity gas sensor with good NH3 detection performance.
Snap-through dynamics of a buckled flexible filament in a channel flow
Authors: Chen Zepeng , Mao Qian , Liu Yingzheng , Sung Hyung Jin
Published: January 2024

The flow-induced snap-through dynamics of a buckled flexible filament in a channel flow was explored using the penalty immersed boundary method. Two edge condition distributions were considered for comparison. One edge condition was a simply supported leading edge and a clamped trailing edge (SC); the other condition was two clamped edges. The effects of channel height and bending rigidity on the energy harvesting performance were systematically examined. The presence of the channel wall compresses the activation space of the vortex, leading to the formation of a high shear flow near the wall, which, in turn, strongly influences the wake pattern. In the snap-through oscillation mode, a wake pattern of 2S + 2P is observed in both narrow and broad channels, whereas the mechanism of vortex shedding varies between the two cases. Both cases demonstrate greater critical rigidity and greater elastic energy compared with conditions under external flow, suggesting an enhancement of the energy harvesting performance. The greater energy harvesting ability of the SC case is derived from both the larger deflection and the higher strain energy in this system. The wall effect is inversely proportional to the channel height, becoming nearly negligible when the nondimensional channel height exceeds 2. These findings provide valuable insights into the dynamics of flexible filaments in the channel flow and their potential for energy harvesting applications.
Numerical study on effect of design parameters of the single-circumferential groove on tip leakage flow reduction in a transonic turbine
Authors: Shi Xuyang , Wu Yanhui , Li Haohua , Li Ziliang
Published: January 2024

In order to investigate the impact of design parameters (depth, width, and location) of the single-circumferential groove (SCG) on tip leakage flow (TLF) reduction in a transonic turbine stage, a systematic investigation was conducted by high-precision numerical simulation method. The numerical results show that the introduction of SCG could improve the stage efficiency (η) of turbine significantly. The optimal design parameters of depth coefficient (ζ), width (W), and location (L) were ζ = 3, W = W3, and L = 20%Cax (where Cax denotes the axial chord of the blade), which could reduce tip clearance leakage rate (m*) by 28.9% and improve the η by 0.56%. The implementation of flow field display methods reveals that the introduction of SCG influences the formation and development of the vortex system at the rotor tip region. The circumferential groove vortex (CGV), induced by SCG, divided the tip leakage vortex (TLV) into two segments TLV_1 and TLV_2 due to its blocking effect. TLV_1 interacted with the passage vortex (PV) and depress the strength of PV. Meantime, TLV_2 would regenerate from the trailing edge of SCG, due to its limited development range and insufficient growth, the strength and scale of TLV_2 were weakened. Given that the TLF passing through SCG flows in an opposite direction to the original TLF, the SCG at appropriate location could lead to a fact that the net flow rate of the leakage flow reached the minimum value, thereby considerably reducing the m* and flow loss caused by TLF.
Numerical study of a composite cooling method for hypersonic aircraft
Authors: Chen Bohong , Tian Xudong , Yi Shihe
Published: January 2024

Thermal protection is a crucial issue for a long-flying hypersonic aircraft. In this work, a composite cooling method is proposed and implemented on a hypersonic blunt cone. The composite cooling method combines impinging and convective cooling at the cone head with transpiration cooling employed downstream to produce an overall cooling effect of the cone. Using computational fluid dynamics, the influences of the cooling gas and different attack angles on the cooling effect are examined. The results indicate that the combined cooling method can effectively reduce the overall outer wall temperature of the cone. In particular, with the combined cooling method, an increase in mass flow rate of the cooling gas has been observed in numerical tests, which results in a decrease in the head temperature. The maximum temperature decrease can reach 77.0% on the wall when the mass flow rate of the cooling stream is 1.1 kg/m2 s. The cooling performance on the leeward side can be better than that on the windward side for a fixed cooling gas mass flow rate. This gap in cooling performance between the two sides can be further amplified by a larger attack angle. Quantitatively, when using the combined cooling method, the temperature difference between the windward and leeward sides increases from 106 to 270 K when the attack angle increases from 4° to 8°. The numerical results in this study could provide theoretical and statistical guidance for the design of novel active thermal protection methods for hypersonic aircraft.
Wattle gall—the quintessential Australian plant disease
Authors: Ryley Malcolm J.
Published: January 2024

Acacia (the wattles) is the largest genus of plants in Australia and its species occupy almost every habitat in the country. Hard galls on the branches, phyllodes and flower parts of wattle trees were noticed from the very early days of British colonisation, but their causes were unknown. Some insects were believed to be involved, but they were not the only cause of wattle galls. In 1889, the Italian mycologist Pier Andrea Saccardo described the rust fungus Uromyces tepperianus from the galls on Acacia salicina, and later, the Victorian government vegetable pathologist, Daniel McAlpine transferred the species tepperianus to his new genus Uromycladium which also included six new species. A total of 28 valid species of Uromycladium, most endemic to Australia, are currently described. Several species of Uromycladium were somehow introduced into South Africa and countries in southeast Asia where they cause significant losses in Acacia plantations, while others are used as biocontrol agents for invasive Acacia species. Short biographies of two of the early collectors of rust galls, the South Australian naturalist and later entomologist Johann Gottlieb Otto Tepper and the Victorian plant pathologist Charles Clifton Brittlebank are also presented.
Drastic magnetic-field-induced chiral current order and emergent current-bond-field interplay in kagome metals
Authors: Tazai Rina , Yamakawa Youichi , Kontani Hiroshi
Published: January 2024

In kagome metals, the chiral current order parameter

η

with time-reversal-symmetry-breaking is the source of various exotic electronic states, while the method of controlling the current order and its interplay with the star-of-David bond order

ϕ

are still unsolved. Here, we reveal that tiny uniform orbital magnetization

M
orb

[

η

,

ϕ

]

is induced by the chiral current order, and its magnitude is prominently enlarged under the presence of the bond order. Importantly, we derive the magnetic-field (

h
z

)-induced Ginzburg–Landau (GL) free energy expression

Δ
F

[

h
z

,

η

,

ϕ

]

∝
−

h
z

M
orb

[

η

,

ϕ

]

, which enables us to elucidate the field-induced current-bond phase transitions in kagome metals. The emergent current-bond-

h
z

trilinear coupling term in the free energy,

−

m
1

h
z

η

·

ϕ

, naturally explains the characteristic magnetic-field sensitive electronic states in kagome metals, such as the field-induced current order and the strong interplay between the bond and current orders. The GL coefficients of

Δ
F
[

h
z

,

η

,

ϕ

]

derived from the realistic multiorbital model are appropriate to explain various experiments. Furthermore, we discuss the field-induced loop current orders in the square lattice models that have been studied in cuprate superconductors.
The types of cues that help you learn
Authors: Romain Laurence , Divjak Dagmar
Published: January 2024

Despite a considerable amount of research conducted on the development of tense/aspect (TA) usage in English by
second language (L2) learners, nuances in uses of TAs remain elusive to many L2 learners of English: the grammatical accounts
proposed appear difficult to apply as they are either too general or too specific and fail to provide learners with a conceptual
understanding of the system. Merging insights from psychological models of learning, corpus-based, and cognitive linguistics
approaches to second language acquisition we use the results of computational simulations of learning of the TA system conducted
by Romain et al. (2022) and propose an approach to TA teaching that focuses on the cues
that have been identified as crucial for accurate TA use. Our pedagogical approach draws learners’ attention not so much to the
cues themselves but to the type of cues that are the most reliable in the choice of different TA combinations. This approach
allows teachers to equip learners with a long-term learning strategy that will help them focus on the most useful type of
information, and thus gradually build up a bank of knowledge specific to each TA combination.
Sustainable Tourism and Stakeholders’ Satisfaction in Batulayang Tourism Village Bogor Indonesia
Authors: Suherlan Ade
Published: January 2024

Desa Wisata Batulayang
(Batulayang Tourism Village) is an emerging tourist destination in Bogor Regency, West Java, Indonesia, offering a unique experience of rural life, traditions, and nature. Developing such tourism villages is vital for the community, providing economic benefits, alleviating poverty, and unemployment, and preserving the environment and culture. Enhancing the availability of job opportunities in rural areas by creating sustainable tourism villages will expand the range of services such as healthcare and education. Consequently, this is expected to reduce the tendency of rural communities to migrate to urban areas.

Desa Wisata Batulayang
adheres to sustainable tourism principles to ensure the village’s long-term sustainability. The success of sustainable tourism hinges on active involvement, satisfaction, and support from various stakeholders. Involving stakeholders in decision making promotes the village’s viability, community development, resource preservation, and economic prosperity.

Information

© The Author 2024
Nonperturbative theory for the QED corrections to elastic electron-nucleus scattering
Authors: Jakubassa-Amundsen D H
Published: January 2024

A potential for the vertex and self-energy correction is derived from the first-order Born theory. The inclusion of this potential in the Dirac equation, together with the Uehling potential for vacuum polarization, allows for a nonperturbative treatment of these quantum electrodynamical effects within the phase-shift analysis. Investigating the 12C and 208Pb targets, a considerable deviation of the respective cross section change from the Born results is found for the heavier target. It is shown that at low impact energies the dispersion effects play no role. Estimates for the correction to the beam-normal spin asymmetry and its accuracy at 5 MeV (for 208Pb and 197Au) are also provided.
Interlayer-coupling-engineerable flat bands in twisted MoSi2N4 bilayers
Authors: Dai Yang , Zhang Zhineng , Zhao Puqin , Cheng Yingchun
Published: January 2024

The two-dimensional layered semiconductor MoSi2N4, which has several advantages including high strength, excellent stability, high hole mobility, and high thermal conductivity, was recently successfully synthesized using chemical vapor deposition. Based on first-principles calculations, we investigate the effects of the twist angle and interlayer distance variation on the electronic properties of twisted bilayer MoSi2N4. The flat bands are absent for twisted bilayer MoSi2N4 when the twist angle θ is reduced to 3.89°. Taking twisted bilayer MoSi2N4 with θ of 5.09° as an example, we find that flat bands emerge as the interlayer distance decreases. As the interlayer distance can be effectively modulated by hydrostatic pressure, we propose hydrostatic pressure as a knob for tailoring the flat bands in twisted bilayer MoSi2N4. Our findings provide theoretical support for extending the applications of MoSi2N4 in strong correlation physics and superconductivity.
Advancing robust state estimation of wheeled robots in degenerate environments: harnessing ground manifold and motion states
Authors: Liang Bowen , Tao Yourui , Zhu Huabo , Song Yao
Published: January 2024

State estimation is crucial for enabling autonomous mobility in mobile robots. However, traditional localization methods often falter in degraded environments, including issues like visual occlusion, lidar performance degradation, and global navigation satellite system signal interference. This paper presents a novel estimation approach for wheeled robots, exclusively utilizing proprioceptive sensors such as encoders and inertial measurement units (IMU). Initially, the motion manifolds extracted from the historical trajectories are used to assist the encoder in realizing the orientation estimation. Furthermore, a hybrid neural network is designed to categorize the robot’s operational state, and the corresponding pseudo-constraints are added to improve the estimation accuracy. We utilize an error state Kalman filter for the encoder and IMU data fusion. Lastly, comprehensive testing is conducted using both datasets and real-world robotic platforms. The findings underscore that the integration of manifold and motion constraints within our proposed state estimator substantially elevates accuracy compared to conventional approaches. Compare with the methods commonly used in engineering, the accuracy of this method is improved by more than 20%. Crucially, this methodology enables dependable estimation even in degraded environments.
A nudge over the relaxation plateau: effect of pH, particle concentration, and medium viscosity on the AC induction heating efficiency of biocompatible chitosan-coated Fe3O4 nanoparticles
Authors: Mahendravada Srujana , Lahiri B B , Khan Fouzia , Sathyanarayana A T , Vizhi R Ezhil , Moorthy Anbalagan , Philip John
Published: January 2024

The effects of pH, MNP concentration, and medium viscosity on the magnetic fluid hyperthermia (MFH) properties of chitosan-coated superparamagnetic Fe3O4 nanoparticles (MNPs) are probed here. Due to the protonation of the amide groups, the MNPs are colloidally stable at lower pH (∼2), but form aggregates at higher pH (∼8). The increased aggregate size at higher pH causes the Brownian relaxation time (τ
B) to increase, leading to a decrease in specific absorption rate (SAR). For colloidal conditions ensuring Brownian-dominated relaxation dynamics, an increase in MNP concentrations or medium viscosity is found to increase the τ
B. SAR decreases with increasing MNP concentration, whereas it exhibits a non-monotonic variation with increasing medium viscosity. Dynamic hysteresis loop-based calculations are found to be in agreement with the experimental results. The findings provide a greater understanding of the variation of SAR with the colloidal properties and show the importance of relaxation dynamics on MFH efficiency, where variations in the frequency-relaxation time product across the relaxation plateau cause significant variations in SAR. Further, the in vitro cytotoxicity studies show good bio-compatibility of the chitosan-coated Fe3O4 MNPs. Higher SAR at acidic pH for bio-medically acceptable field parameters makes the bio-compatible chitosan-coated Fe3O4 MNPs suitable for MFH applications.
Investigation of SiGe/Si heterojunction inductive line tunneling TFET with source Schottky contact for prospect ultra-low power applications
Authors: Lin Jyi-Tsong , Yang Ruei-Kai
Published: January 2024

In this paper, a SiGe/Si heterojunction inductive line tunneling tunnel field-effect transistor with source Schottky contact (SC HJLT-iTFET) is proposed and investigated by the Sentaurus Technology Computer Aided Design (TCAD) simulator. By utilizing an appropriate source Schottky metal, the need for multiple ion implantation and annealing steps required for traditional P–I–N TFETs can be avoided, and the problems of self-alignment and random dopant fluctuations (RDF) during ion implantation can be solved. A high ON-state current (I
ON) is obtained as fully overlapping the source and gate by line tunneling mechanism dominated, the appropriate Si1−x
Ge
x
mole fraction material in the source region and high-k gate dielectric employed can further improve I
ON. The incorporation of the block layer effectively decreases the lateral electric field at the drain end to reduce the OFF-state current (I
OFF). Furthermore, the proposed charge enhancement layer (CEL) on the SiGe channel can suppress the Fermi level pinning effect (FLP) and enhance the charge of the source region. Based on the feasibility of the practical fabrication process, and the rigorous simulations indicate that the device has an SSavg of 19.8 mV/dec and SSmin of 6.8 mV/dec at V
D = 0.2 V, I
ON of 2.27 × 10−6 A

μ

m−1, and an I
ON/I
OFF ratio of 1.02 × 1010, with extremely fast switching speed. These features make the device suitable for future ultra-low power applications on the internet of things, artificial intelligence, and related fields.
Simulation and experimental results of plasma opening switch operation with inductive and electron beam diode loads in different plasma regimes
Authors: Kanchi Sunil , Shukla Rohit , Sharma Archana
Published: January 2024

This paper reports the experimental results of a plasma opening switch (POS) that operates at hydrogen and carbon plasma regimes confirmed based on the conduction bipolar limit of the plasma species and the availability of plasma species during the conduction based on the density profiles. The generator is the compact capacitor bank developed using the synchronization of four field distortion spark gap switches. The plasma source is coaxial cable plasma guns characterized using the Faraday cup plasma diagnostic. The experimental results are compared with the time domain simulation code in which the POS is represented as the dynamic resistance governed by the physical equations of the bipolar model. The experiments and simulations are compared for inductive load and dynamic load of accelerating gap of 5 mm between the anode and cathode at the load end. From the results, POS can be operated based on the availability of plasma species with proper synchronized triggering between the plasma gun firing and generator firing that can operate at low and high values of currents.
Sound insulation performance of membrane-type acoustic metamaterial based on defect state structure
Authors: Cai Tong , Huang Shuang , Guo Hui , Yuan Tao , Sun Pei , Liu NingNing
Published: January 2024

Although conventional Membrane-type Acoustic Metamaterial(MAM) has good sound insulation performance in low frequency bands, the sound insulation performance in middle and high frequency bands is not as good as conventional sound insulation materials with the same quality. This problem still persists by using the double-layer MAM structures. To solve this problem, the defect state is introduced into the double-layer MAM structure. Although the ideal periodic structure is destroyed, the sound insulation performance will also change greatly, and it has a strong creativity. In this paper, the sound insulation performance of MAM with defect states is studied. Firstly, the theoretical model of sound insulation of double-layer membrane-type acoustic metamaterial with eccentric composite mass block (MAMEM) structure is calculated by using modal superposition method and transfer matrix method. Secondly, the influence of different defect locations on the sound insulation of membrane-type acoustic metamaterial with eccentric composite mass block(MAMECM) structure is discussed. The results show that the sound insulation peaks of the angular defect structure appear at 300 Hz, 320 Hz, 1040 Hz and 1410 Hz. The average sound insulation in the whole study frequency band of the angular defect structure is 4.23 dB higher than the non-defect structure. In addition, the experiment verifies the accuracy of the results. Thirdly, based on genetic algorithm, the area enclosed by the sound translation loss (STL) curve of the double-layer MAMECM structure above the mass law curve is taken as the optimization target to optimize the structure topology. The results show that the optimal structure not only has good sound insulation performance in the low frequency band, but also reaches the sound insulation peak at 1230 Hz, 1300 Hz, 1430 Hz and 1450 Hz. Besides, the optimal structure heaviness is reduced by 12%.
Mode-locked Yb:CALGO laser with high peak power sub-100 fs pulses at 26.9 MHz repetition rate
Authors: Reza Md A R , Major A
Published: January 2024

The development of a diode-pumped high peak power sub-100 fs mode-locked Yb:CALGO laser is presented. The laser delivered 1.3 W of output power with 81 fs pulses at a repetition rate of 26.9 MHz. The corresponding pulse energy was 48 nJ and the peak power was 596 kW. The cavity was extended by using a 1:1 imaging telescope. Mode locking was based on a semiconductor saturable absorber mirror and chirped mirrors were used to compensate for the positive dispersion in the cavity. To the best of our knowledge, this is one of the shortest pulse durations obtained from Yb:CALGO laser around this low repetition rate.
Neural signal data collection and analysis of Percept™ PC BrainSense recordings for thalamic stimulation in epilepsy
Authors: Sanger Zachary T , Henry Thomas R , Park Michael C , Darrow David , McGovern Robert A , Netoff Theoden I
Published: January 2024

Deep brain stimulation (DBS) using Medtronic’s Percept™ PC implantable pulse generator is FDA-approved for treating Parkinson’s disease (PD), essential tremor, dystonia, obsessive compulsive disorder, and epilepsy. Percept™ PC enables simultaneous recording of neural signals from the same lead used for stimulation. Many Percept™ PC sensing features were built with PD patients in mind, but these features are potentially useful to refine therapies for many different disease processes. When starting our ongoing epilepsy research study, we found it difficult to find detailed descriptions about these features and have compiled information from multiple sources to understand it as a tool, particularly for use in patients other than those with PD. Here we provide a tutorial for scientists and physicians interested in using Percept™ PC’s features and provide examples of how neural time series data is often represented and saved. We address characteristics of the recorded signals and discuss Percept™ PC hardware and software capabilities in data pre-processing, signal filtering, and DBS lead performance. We explain the power spectrum of the data and how it is shaped by the filter response of Percept™ PC as well as the aliasing of the stimulation due to digitally sampling the data. We present Percept™ PC’s ability to extract biomarkers that may be used to optimize stimulation therapy. We show how differences in lead type affects noise characteristics of the implanted leads from seven epilepsy patients enrolled in our clinical trial. Percept™ PC has sufficient signal-to-noise ratio, sampling capabilities, and stimulus artifact rejection for neural activity recording. Limitations in sampling rate, potential artifacts during stimulation, and shortening of battery life when monitoring neural activity at home were observed. Despite these limitations, Percept™ PC demonstrates potential as a useful tool for recording neural activity in order to optimize stimulation therapies to personalize treatment.
Topology of 2D Dirac operators with variable mass and an application to shallow-water waves
Authors: Rossi Sylvain , Tarantola Alessandro
Published: January 2024

A Dirac operator on the plane with constant (positive) mass is a Chern insulator, sitting in class D of the Kitaev table. Despite its simplicity, this system is topologically ill-behaved: the non-compact Brillouin zone prevents definition of a bulk invariant, and naively placing the model on a manifold with boundary results in violations of the bulk-edge correspondence (BEC). We overcome both issues by letting the mass spatially vary in the vertical direction, interpolating between the original model and its negative-mass counterpart. Proper bulk and edge indices can now be defined. They are shown to coincide, thereby embodying BEC.

The shallow-water model exhibits the same illnesses as the 2D massive Dirac. Identical problems suggest identical solutions, and indeed extending the approach above to this setting yields proper indices and another instance of BEC.
How well does your e-nose detect cancer? Application of artificial breath analysis for performance assessment
Authors: Martin Justin D M , Claudia Falzone , Romain Anne-Claude
Published: January 2024

Comparing electronic nose (e-nose) performance is a challenging task because of a lack of standardised method. This paper proposes a method for defining and quantifying an indicator of the effectiveness of multi-sensor systems in detecting cancers by artificial breath analysis. To build this method, an evaluation of the performances of an array of metal oxide sensors built for use as a lung cancer screening tool was conducted. Breath from 20 healthy volunteers has been sampled in fluorinated ethylene propylene sampling bags. These healthy samples were analysed with and without the addition of nine volatile organic compound (VOC) cancer biomarkers, chosen from literature. The concentration of the VOC added was done in increasing amounts. The more VOC were added, the better the discrimination between ‘healthy’ samples (breath without additives) and ‘cancer’ samples (breath with additives) was. By determining at which level of concentration the e-nose fails to reliably discriminate between the two groups, we estimate its ability to well predict the presence of the disease or not in a realistic situation. In this work, a home-made e-nose is put to the test. The results underline that the biomarkers need to be about 5.3 times higher in concentration than in real breath for the home-made nose to tell the difference between groups with a sufficient confidence.
Carbon emission disclosure in the agriculture industry in Indonesia: The determinant factors
Authors: Ika S R , Puisi P U I S I , Vitaningsih C W , Ducati D , Widagdo A K
Published: January 2024

The agriculture industry in Indonesia, despite its huge contribution to the country’s economy, is responsible for a substantial amount of carbon emissions. Hence, according to the country’s stock exchange regulation, agriculturally listed companies shall annually report their carbon emissions and carbon emission mitigation. The main objective of our research is to analyze the factors that influence the reporting of greenhouse gas emissions by agriculture corporations. The examined factors are environmental performance, which is assessed through environmental performance ratings and environmental management certification, the released sustainability report, ownership structure, and financial characteristics. Using 91 publicly traded agriculture companies from 2019 to 2022 as a sample, the ordinally least squares regression analysis shows that publications of a company’s carbon emissions tend to rise in accordance with both the rating of its environmental performance and the issuance of its sustainability report. Institutional ownership and financial characteristics of a company do not have any relationship with the extent of carbon emission disclosures. This study delivers an understanding to the Financial Service Authority Agency that the environmental performance rating assessment by the KLH and the yearly sustainability report encourage companies to do activities related to environmental sustainability.
Access and function of oil palm farmers to information and communication technology in Riau Province, Indonesia
Authors: Yulida R , Rosnita R , Andriani Y , Septya F , Herlon M , Ikhwan M
Published: January 2024

Based on a 2018 study, it was discovered that nearly 60% of oil palm farmers in Riau Province have embraced the use of smartphones. This trend presents an opportunity for information and communication technology to be leveraged in oil palm development initiatives. The research aimed to explore how oil palm farmers utilize technology and access information. The survey method was employed, and respondents were selected from two districts in Riau Province where oil palm plantations have been developed and replanted. Only farmers who use smartphones were included, resulting in a sample size of 279. The study utilized quantitative descriptive analysis to examine farmers’ access to and use of smartphone technology. The findings show that farmers primarily use smartphones for entertainment, with WhatsApp and Facebook being the most popular apps. However, only 16% of farmers use their smartphones to check palm oil prices online, and a mere 3% have accessed websites for knowledge and skills relevant to oil palm farming. The study recommends the creation of social media apps that are user-friendly, easily accessible, and present information in a clear and understandable format.
Decay of Taylor–Green flow type initial conditions in a two-dimensional domain
Authors: Kandre Shivakumar , Patil Dhiraj V
Published: January 2024

Geophysical flows are often two-dimensional (2D) in nature. The decay dynamics of the canonical, symmetric initial conditions defined by the Taylor–Green (TG) flow is simulated in a 2D domain. The standard lattice Boltzmann equation method with the Bhatnagar–Gross–Krook collision model is employed. The vortex dynamics is investigated for bounded and unbounded flows with various sets of Gaussian vortices and varying Reynolds numbers. The formation of thin filaments and the generation of small-scale structures near the no-slip walls are found. To characterize the decay properties, the integral quantities, namely, kinetic energy, E(t), enstrophy,

Ω
(
t
)

, and palinstrophy, P(t), are tracked as a function of the eddy-turnover-time. The initial vortex population in the domain dictates the decay rate of these integral quantities. The energy spectra, E(k), are computed to investigate the effect of domain boundaries and vortex populations on energy distribution among different length scales for

Re

=
50
000

. The evolution of TG flow in a bounded domain shows an exponent close to −3, which may be attributed to the generation of thin filaments and small-scale structures in vortex-wall interactions. Exponent changes with an increase in the vortex populations.
ATSFCNN: a novel attention-based triple-stream fused CNN model for hyperspectral image classification
Authors: Cai Jizhen , Boust Clotilde , Mansouri Alamin
Published: January 2024

Recently, the convolutional neural network (CNN) has gained increasing importance in hyperspectral image (HSI) classification thanks to its superior performance. However, most of the previous research has mainly focused on 2D-CNN, and the limited applications of 3D-CNN have been attributed to its complexity, despite its potential to enhance information extraction between adjacent channels of the image. Moreover, 1D-CNN is typically restricted to the field of signal processing as it ignores the spatial information of HSIs. In this paper, we propose a novel CNN model named attention-based triple-stream fused CNN (ATSFCNN) that fuses the features of 1D-CNN, 2D-CNN, and 3D-CNN to consider all the relevant information of the hyperspectral dataset. Our contributions are twofold: First, we propose a strategy to extract and homogenize features from 1D, 2D, and 3D CNN. Secondly, we propose a way to efficiently fuse these features. This attention-based methodology adeptly integrates features from the triple streams, thereby transcending the former limitations of singular stream utilization. Consequently, it becomes capable of attaining elevated outcomes in the context of hyperspectral classification, marked by increased levels of both accuracy and stability. We compared the results of ATSFCNN with those of other deep learning models, including 1D-CNN, 2D-CNN, 2D-CNN+PCA, 3D-CNN, and 3D-CNN+PCA, and demonstrated its superior performance and robustness. Quantitative assessments, predicated on the metrics of overall accuracy (OA), average accuracy (AA), and kappa coefficient (κ) emphatically corroborate the preeminence of ATSFCNN. Notably, spanning the three remote sensing datasets, ATSFCNN consistently achieves peak levels of OA, quantified at 98.38%, 97.09%, and 96.93% respectively. This prowess is further accentuated by concomitant AA scores of 98.47%, 95.80%, and 95.80%, as well as kappa coefficient values amounting to 97.41%, 96.14%, and 95.21%.
Midgap state requirements for optically active quantum defects
Authors: Xiong Yihuang , Mathew Milena , Griffin Sinéad M , Sipahigil Alp , Hautier Geoffroy
Published: January 2024

Optically active quantum defects play an important role in quantum sensing, computing and communication. The electronic structure and the single-particle energy levels of these quantum defects in the semiconducting host have been used to understand their optoelectronic properties. Optical excitations that are central for their initialization and readout are linked to transitions between occupied and unoccupied single-particle states. It is commonly assumed that only quantum defects introducing levels well within the band gap and far from the band edges are of interest for quantum technologies as they mimic an isolated atom embedded in the host. In this perspective, we contradict this common assumption and show that optically active defects with energy levels close to the band edges can display similar properties. We highlight quantum defects that are excited through transitions to or from a band-like level (bound exciton) such as the T center and Se

S
i

+

in silicon. We also present how defects such as the silicon split-vacancy in diamond can involve transitions between localized levels that are above the conduction band or below the valence band. Loosening the commonly assumed requirement on the electronic structure of quantum defects offers opportunities in quantum defects design and discovery especially in smaller band gap hosts such as silicon. We discuss the challenges in terms of operating temperature for photoluminescence or radiative lifetime in this regime. We also highlight how these alternative type of defects bring their own needs in terms of theoretical developments and fundamental understanding. This perspective clarifies the electronic structure requirement for quantum defects and will facilitate the identification and design of new color centers for quantum applications especially driven by first principles computations.
The Aesthetic Surgery Education and Research Foundation (ASERF): A 30-Year Retrospective Analysis
Authors: Gryskiewicz Joe , Slavin Blaire V , Slavin Benjamin R , Nayak Vasudev Vivekanand , Pierrot Randall G , Taghioff Susan M , Alameddine Khaled O , Singh Devinder , Chopra Karan , Coelho Paulo G
Published: January 2024

Federal government research grants provide limited funding to plastic surgeon-scientists, with reconstructive research taking precedence over aesthetic research. The Aesthetic Surgery Education and Research Foundation (ASERF) is a nonprofit, 501(c)(3) organization that seeks to support innovative, diverse research endeavors within aesthetic surgery. A total of 130 ASERF-funded studies and 32 non-funded applications from 1992 to 2022 were reviewed. Kruskal Wallis, Fisher's exact, and chi-squared tests were utilized to assess the potential relationship between self-identified gender, practice setting, geographical location, and study type with individual grant amounts and grant funding decision. Although significant differences were observed between male and female grant recipient h-indices (P < .05), there were no differences in the amount of funding they received (P > .05). Grant amounts were also consistent between study types as well as principal investigator practice settings and geographical locations (P > .05). The subanalysis revealed that the practice setting of the primary investigator (PI) was the only variable to exhibit a significant association with the decision to award funding (P < .05). Further, of the 61 applicants between 2017 and 2022, only 2 PIs self-identified as female. ASERF serves as an excellent funding source for global aesthetic surgery. To promote further research diversification, increased emphasis should be placed on recruiting applicants from outside academia and those who identify as female or gender nonbinary.
Pathway analysis through mutual information
Authors: Jeuken Gustavo S , Käll Lukas
Published: January 2024

Motivation

In pathway analysis, we aim to establish a connection between the activity of a particular biological pathway and a difference in phenotype. There are many available methods to perform pathway analysis, many of them rely on an upstream differential expression analysis, and many model the relations between the abundances of the analytes in a pathway as linear relationships.

Results

Here, we propose a new method for pathway analysis, MIPath, that relies on information theoretical principles and, therefore, does not model the association between pathway activity and phenotype, resulting in relatively few assumptions. For this, we construct a graph of the data points for each pathway using a nearest-neighbor approach and score the association between the structure of this graph and the phenotype of these same samples using Mutual Information while adjusting for the effects of random chance in each score. The initial nearest neighbor approach evades individual gene-level comparisons, hence making the method scalable and less vulnerable to missing values. These properties make our method particularly useful for single-cell data. We benchmarked our method on several single-cell datasets, comparing it to established and new methods, and found that it produces robust, reproducible, and meaningful scores.

Availability and implementation

Source code is available at https://github.com/statisticalbiotechnology/mipath, or through Python Package Index as “mipathway.”
GatekeepR: an R Shiny application for the identification of nodes with high dynamic impact in Boolean networks
Authors: Weidner Felix M , Ikonomi Nensi , Werle Silke D , Schwab Julian D , Kestler Hans A
Published: January 2024

Motivation

Boolean networks can serve as straightforward models for understanding processes such as gene regulation, and employing logical rules. These rules can either be derived from existing literature or by data-driven approaches. However, in the context of large networks, the exhaustive search for intervention targets becomes challenging due to the exponential expansion of a Boolean network’s state space and the multitude of potential target candidates, along with their various combinations. Instead, we can employ the logical rules and resultant interaction graph as a means to identify targets of specific interest within larger-scale models. This approach not only facilitates the screening process but also serves as a preliminary filtering step, enabling the focused investigation of candidates that hold promise for more profound dynamic analysis. However, applying this method requires a working knowledge of R, thus restricting the range of potential users. We, therefore, aim to provide an application that makes this method accessible to a broader scientific community.

Results

Here, we introduce GatekeepR, a graphical, web-based R Shiny application that enables scientists to screen Boolean network models for possible intervention targets whose perturbation is likely to have a large impact on the system’s dynamics. This application does not require a local installation or knowledge of R and provides the suggested targets along with additional network information and visualizations in an intuitive, easy-to-use manner. The Supplementary Material describes the underlying method for identifying these nodes along with an example application in a network modeling pancreatic cancer.

Availability and implementation

https://www.github.com/sysbio-bioinf/GatekeepR https://abel.informatik.uni-ulm.de/shiny/GatekeepR/.