bluuebunny/crossref_metadata_2025 huggingface dataset:
Cu2+ and Cu3+ acceptors in β-Ga2O3 crystals: A magnetic resonance and optical absorption study
Authors: Gustafson T. D. , Giles N. C. , Holloway B. C. , Lenyk C. A. , Jesenovec J. , McCloy J. S. , McCluskey M. D. , Halliburton L. E.
Published: February 2022

Electron paramagnetic resonance (EPR) and optical absorption are used to characterize Cu2+ (3d9) and Cu3+ (3d8) ions in Cu-doped β-Ga2O3. These Cu ions are singly ionized acceptors and neutral acceptors, respectively (in semiconductor notation, they are Cu− and Cu0 acceptors). Two distinct Cu2+ EPR spectra are observed in the as-grown crystals. We refer to them as Cu2+(A) and Cu2+(B). Spin-Hamiltonian parameters (a g matrix and a 63,65Cu hyperfine matrix) are obtained from the angular dependence of each spectrum. Additional electron-nuclear double resonance (ENDOR) experiments on Cu2+(A) ions give refined 63Cu and 65Cu hyperfine matrices and provide information about the nuclear electric quadrupole interactions. Our EPR results show that the Cu2+(A) ions occupy octahedral Ga sites with no nearby defect. The Cu2+(B) ions, also at octahedral Ga sites, have an adjacent defect, possibly an OH− ion, an oxygen vacancy, or an H− ion trapped within an oxygen vacancy. Exposing the crystals at room temperature to 275 nm light produces Cu3+ ions and reduces the number of Cu2+(A) and Cu2+(B) ions. The Cu3+ ions have an S = 1 EPR spectrum and are responsible for broad optical absorption bands peaking near 365, 422, 486, 599, and 696 nm. An analysis of loops observed in the Cu3+ EPR angular dependence gives 2.086 for the g value and 22.18, 3.31, and −25.49 GHz for the principal values of D (the fine-structure matrix). Thermal anneal studies above room temperature show that the Cu3+ ions decay and the Cu2+ ions recover between 75 and 375 °C.
Spatiotemporal evolution of emission and absorption signatures in a laser-produced plasma
Authors: Harilal S. S. , Kautz E. J. , Phillips M. C.
Published: February 2022

We report spatiotemporal evolution of emission and absorption signatures of Al species in a nanosecond (ns) laser-produced plasma (LPP). The plasmas were generated from an Inconel target, which contained ∼0.4 wt. % Al, using 1064 nm, ≈6 ns full width half maximum pulses from an Nd:YAG laser at an Ar cover gas pressure of ≈34 Torr. The temporal distributions of the Al I (394.4 nm) transition were collected from various spatial points within the plasma employing time-of-flight (TOF) emission and laser absorption spectroscopy, and they provide kinetics of the excited state and ground state population of the selected transition. The emission and absorption signatures showed multiple peaks in their temporal profiles, although they appeared at different spatial locations and times after the plasma onset. The absorption temporal profiles showed an early time signature representing shock wave propagation into the ambient gas. We also used emission and absorption spectral features for measuring various physical properties of the plasma. The absorption spectral profiles are utilized for measuring linewidths, column density, and kinetic temperature, while emission spectra were used to measure excitation temperature. A comparison between excitation and kinetic temperature was made at various spatial points in the plasma. Our results highlight that the TOF measurements provide a resourceful tool for showing the spatiotemporal LPP dynamics with higher spatial and temporal resolution than is possible with spectral measurements but are difficult to interpret without additional information on excitation temperatures and linewidths. The combination of absorption and emission TOF and spectral measurements thus provides a more complete picture of LPP spatiotemporal dynamics than is possible using any one technique alone.
Control of the flow around a finite square cylinder with a flexible plate attached at the free end
Authors: Wang Hanfeng , Zhao Chongyu , Zeng Lingwei , Mahbub Alam Md. , Tang Hui
Published: February 2022

A flexible plate vertically clamped at the free-end leading edge was used to modulate the aerodynamic forces on a wall-mounted finite square cylinder. The side width (d) of the cylinder was 40 mm and the aspect ratio (H/d) was 5. The flexible plate was made of low-density polyethylene, with a width of d and thickness of 0.04 mm. The length of the flexible plate ranged from d/8 to d. All measurements were carried out in a low-speed wind tunnel with the free-stream velocity (U∞) ranging from 4 to 20 m/s, corresponding to a Reynolds number ranging from 10 960 to 54 800. It was found that the flexible plate behaves distinctly depending on its length and has significant effects on the aerodynamic forces on the finite square cylinder. When U∞ is smaller than the critical velocity Ucr, which is closely related to the length of the plate, the plate statically deforms, having a negligible influence on the aerodynamic forces on the cylinder. When U∞ exceeds Ucr, the plate flaps periodically, resulting in a significant reduction in the aerodynamic forces. The maximum reduction in the mean drag, fluctuating drag, and fluctuating lateral force reaches approximately 5%, 25%, and 60%, respectively. The reduction in the aerodynamic forces is insensitive to both the plate length and flapping frequency. Flow visualization and particle image velocimetry results point out that the flapping plate induces large-scale vortices in the free-end shear flow, which suppress the formation of spanwise vortex shedding and make the upper part of the near wake symmetrical. The flapping configuration of the flexible plate and the corresponding pressure fluctuation on the free end were also addressed.
Double diffusive convective motion in a reactive porous medium layer saturated by a non-Newtonian Kuvshiniski fluid
Authors: Yadav Dhananjay , Kumar Awasthi Mukesh , Al-Siyabi M. , Al-Nadhairi S. , Al-Rahbi A. , Al-Subhi M. , Ragoju Ravi , Bhattacharyya Krishnendu
Published: February 2022

The impact of chemical reactions on the double-diffusive convective motion in a non-Newtonian viscoelastic fluid (Kuvshiniski type) saturated porous layer is examined applying both linear and nonlinear stability techniques. The Darcy model that includes the Kuvshiniski type viscoelastic effect of viscoelastic fluid and the Boussinesq estimation is employed as the momentum equation. The conditions for the occurrence of the stationary and oscillatory style of convective motions are determined by applying linear stability theory in terms of a critical thermal Rayleigh–Darcy number. Using the weakly nonlinear stability analysis, the convective heat and mass transfers are calculated. It is observed that the occurrence of oscillatory convection is possible only if the value of the solute Rayleigh–Darcy number is negative and also depends on other involved physical parameters. With rising values of the Kuvshiniski parameter and the heat capacity ratio, the range of the solute Rayleigh–Darcy number in which oscillatory convection is privileged diminishes, whereas it grows with the chemical reacting parameter and the Lewis number. The critical thermal Rayleigh–Darcy number at which the convective motion occurs increased nearly 3% with a 15% increase in the value of the Kuvshiniski parameter. Furthermore, the convective heat and mass transfers are reduced by growing the Kuvshiniski parameter and the heat capacity ratio, while both are enhanced by increasing the thermal Rayleigh–Darcy number and the solute Rayleigh–Darcy number.
Droplet impact dynamics onto a deep liquid pool of wavy free surface
Authors: Singh Abhishek , Kumar Parmod
Published: February 2022

The impact of a droplet on a deep pool of water with a flat-free surface results in a deep cavity followed by the emergence of a thick jet with a secondary drop when the Froude number and Weber number of the impacting droplet are 220 and 252, respectively. The disturbances in the free surface of the liquid pool modify the crater and the jet dynamics under identical drop impact conditions. Here, we present the simulations of the water drop impact on a deep liquid pool having various wavy profiles mimicking the free surface ripples. Long slender jets with the formation of multiple secondary droplets are observed when the droplet impacts the trough of an axisymmetric wavy surface. The influence of wave number on the wavy profile becomes more pronounced at large wave amplitudes. While capillary-inertia instability governs the pinch-off of thick Worthington jets, the pinch-off of these slender jets is found to be mainly inertia driven. However, if the drop impacts the crest of an axisymmetric wave, a short thick jet forms with one or two secondary droplets. Axisymmetric waves with radially outward moving interface, as in ripples, showed the occurrence of complete coalescence when droplet impacted on the crest; but the dynamics remain mostly the same as that of a stationary wave for the droplet impact on a trough. Entrainment of air bubbles after cavity collapse and bent jet occurred for an impact on a sinusoidal planar wave when the impact location was in between the two consecutive extremes.
Geostatistical tools to assess shifts in recreational fishing
Authors: Burchert Shannon J. , Hyndes Glenn A. , Ryan Karina L. , Mueller Ute
Published: February 2022

The use of geostatistical indices to examine fishery-dependent data over time is novel. We assess the value of a range of these indices for describing trends in boat-based recreational fishing in Western Australia and areas of high effort and catches for two demersal species with varying biological characteristics, life histories and distributions. The number of blocks (10- × 10-nautical mile (~19- × 19-km) area) visited decreased by 40%, while the number of fishing trips with demersal species catch increased by 15%. Spatial indices showed a south-easterly shift in demersal catch per unit effort (CPUE) across survey years. The southerly shift of West Australian dhufish (Glaucosoma herbraicum) CPUE and subsequent return to the north likely to reflect the response of this temperate species to a marine heatwave. In comparison, CPUE of retained Baldchin groper (Choerodon rubescens) shifted north, whereas released catches shifted south with high probabilities of hotspots present associated with habitat structure. We identified hotspots of retained and released CPUE, highlighting potential areas where species experience high post-release mortality through barotrauma, and targeted spatial management strategies. Spatial indices allow quantitative definition of the structure of the fishery, identify high catch areas, and assess changes over time at a broader scale to sustainably manage multispecies fisheries.
Bivalent recognition of fatty acyl-CoA by a human integral membrane palmitoyltransferase
Authors: Lee Chul-Jin , Stix Robyn , Rana Mitra S. , Shikwana Flowreen , Murphy R. Elliot , Ghirlando Rodolfo , Faraldo-Gómez José D. , Banerjee Anirban
Published: February 2022

Significance

Protein palmitoylation is one of the most highly abundant protein modifications, through which long-chain fatty acids get attached to cysteines by a thioester linkage. It plays critically important roles in growth signaling, the organization of synaptic receptors, and the regulation of ion channel function. Yet the molecular mechanism of the DHHC family of integral membrane enzymes that catalyze this modification remains poorly understood. Here, we present the structure of a precatalytic complex of human DHHC20 with palmitoyl CoA. Together with the accompanying functional data, the structure shows how a bivalent recognition of palmitoyl CoA by the DHHC enzyme, simultaneously at both the fatty acyl group and the CoA headgroup, is essential for catalytic chemistry to proceed.
Phonetic listen-and-repeat training alters 6–7-year-old children’s non-native vowel contrast production after one
training session
Authors: Immonen Katja , Alku Paavo , Peltola Maija S.
Published: February 2022

The present study investigated children’s ability to learn to produce a non-native vowel contrast through a
listen-and-repeat training method that is traditionally used in foreign language classrooms. Sixteen Finnish preschoolers (aged
6–7 years) were tested. The stimuli were two semi-synthetic pseudo words with the familiar vowel /y/ and the novel vowel /ʉ/
embedded in the first syllable. The procedure included four training and four recording sessions on two consecutive days. The
vowels produced by the children were acoustically analyzed to obtain the average values of the first and second formant. The
results showed that the participants changed their production of /ʉ/ towards the acoustic model after the first training and the
change remained throughout the experiment. Our findings suggest 6–7-year-old children learn to produce a non-native vowel contrast
even with limited L2 sound exposure in a listen-and-repeat training setting.
Moderators of the coach leadership and athlete motivation relationship
Authors: López de Subijana Cristina , Martin Luc J. , McGuire Cailie S. , Côté Jean
Published: February 2022

The purpose of this study was to determine whether the relationship between coach leadership and athlete motivation was moderated by age, gender, competition level, and seasons spent with a coach. This study involved data from two previous studies that explored this relationship yet provides a novel perspective through the lens of important moderators. Three‐hundred and three athletes (M age = 17.6 years; SD = 3.20; 49.7% women and 50.3% men) responded to questionnaires pertaining to their coaches’ leadership behaviours and their own sport motivation. Multiple regression analyses using moderators were conducted. Age, competition level, and seasons spent with the coach significantly moderated the relationships of interest. Coach transformational leadership predicted intrinsic and extrinsic motivation to a greater extent when athletes were younger than 20.8 and 18.2 years of age, respectively. Further, coach transactional leadership predicted intrinsic and extrinsic motivation to a greater extent when athletes had trained for more than two seasons with their coach. Results emphasize the need to consider athlete characteristics from both research and practitioner perspectives. Herein, we advocate for increased awareness amongst key sport stakeholders on the influence that a coach can have on younger athletes’ motivation and the importance of developing coach‐athlete relationships over time.
Differential metabolism of arsenicals regulates Fps1-mediated arsenite transport
Authors: Lee Jongmin , Levin David E.
Published: February 2022

Arsenic is an environmental toxin that exists mainly as pentavalent arsenate and trivalent arsenite. Both forms activate the yeast SAPK Hog1 but with different consequences. We describe a mechanism by which cells distinguish between these arsenicals through one-step metabolism to differentially regulate the bidirectional glycerol channel Fps1, an adventitious port for arsenite. Cells exposed to arsenate reduce it to thiol-reactive arsenite, which modifies a set of cysteine residues in target proteins, whereas cells exposed to arsenite metabolize it to methylarsenite, which modifies an additional set of cysteine residues. Hog1 becomes arsenylated, which prevents it from closing Fps1. However, this block is overcome in cells exposed to arsenite through methylarsenylation of Acr3, an arsenite efflux pump that we found also regulates Fps1 directly. This adaptation allows cells to restrict arsenite entry through Fps1 and also allows its exit when produced from arsenate exposure. These results have broad implications for understanding how SAPKs activated by diverse stressors can drive stress-specific outputs.
Single-cell transcriptomic analysis of human colonic macrophages reveals niche-specific subsets
Authors: Domanska Diana , Majid Umair , Karlsen Victoria T. , Merok Marianne A. , Beitnes Ann-Christin Røberg , Yaqub Sheraz , Bækkevold Espen S. , Jahnsen Frode L.
Published: February 2022

Macrophages are a heterogeneous population of cells involved in tissue homeostasis, inflammation, and cancer. Although macrophages are densely distributed throughout the human intestine, our understanding of how gut macrophages maintain tissue homeostasis is limited. Here we show that colonic lamina propria macrophages (LpMs) and muscularis macrophages (MMs) consist of monocyte-like cells that differentiate into multiple transcriptionally distinct subsets. LpMs comprise subsets with proinflammatory properties and subsets with high antigen-presenting and phagocytic capacity. The latter are strategically positioned close to the surface epithelium. Most MMs differentiate along two trajectories: one that upregulates genes associated with immune activation and angiogenesis, and one that upregulates genes associated with neuronal homeostasis. Importantly, MMs are located adjacent to neurons and vessels. Cell–cell interaction and gene network analysis indicated that survival, migration, transcriptional reprogramming, and niche-specific localization of LpMs and MMs are controlled by an extensive interaction with tissue-resident cells and a few key transcription factors.
Gravity of two photon decay and its quantum coherence
Authors: Mackewicz Kris , Hogan Craig
Published: February 2022

A linear analytical solution is derived for the gravitational shock wave produced by a particle of mass M that decays into a pair of null particles. The resulting space-time is shown to be unperturbed and isotropic, except for a discontinuous perturbation on a spherical null shell. Formulae are derived for the perturbation as a function of polar angle, as measured by an observer at the origin observing clocks on a sphere at distance R. The effect of the shock is interpreted physically as an instantaneous displacement in time and velocity when the shock passes the clocks. The time displacement is shown to be anisotropic, dominated by a quadrupole harmonic aligned with the particle-decay axis, with a magnitude δτ ∼ GM/c
3, independent of R. The velocity displacement is isotropic. The solution is used to derive the gravitational effect of a quantum state with a superposition of a large number of randomly oriented, statistically isotropic particle decays. This approach is shown to provide a well-controlled approximation to estimate the magnitude of gravitational fluctuations in systems composed of null point particles up to the Planck energy in a causal diamond of duration τ = 2R/c, as well as quantum-gravitational fluctuations of black holes and cosmological horizons. Coherent large-angle quantum distortions of macroscopic geometry from fluctuations up to the Planck scale are shown to grow linearly with the duration, with a variance ⟨δτ
2⟩ ∼ τt
P much larger than that produced in models without causal quantum coherence.
Delayed rebounds in the two-ball bounce problem
Authors: Bartz Sean P
Published: February 2022

In the classroom demonstration of a tennis ball dropped on top of a basketball, the surprisingly high bounce of the tennis ball is typically explained using momentum conservation for elastic collisions, with the basketball-floor collision treated as independent from the collision between the two balls. This textbook explanation is extended to inelastic collisions by including a coefficient of restitution. This independent contact model (ICM), as reviewed in this paper, is accurate for a wide variety of cases, even when the collisions are not truly independent. However, it is easy to explore situations that are not explained by the ICM, such as swapping the tennis ball for a ping-pong ball. In this paper, we study the conditions that lead to a ‘delayed rebound effect,’ a small first bounce followed by a higher second bounce, using techniques accessible to an undergraduate student. The dynamical model is based on the familiar solution of the damped harmonic oscillator. We focus on making the equations of motion dimensionless for numerical simulation, and reducing the number of parameters and initial conditions to emphasize universal behavior. The delayed rebound effect is found for a range of parameters, most commonly in cases where the first bounce is lower than the ICM prediction.
Inverse obstacle scattering for elastic waves in the time domain
Authors: Zhao Lu , Dong Heping , Ma Fuming
Published: February 2022

This paper concerns an inverse elastic scattering problem which is to determine a rigid obstacle from time domain scattered field data for a single incident plane wave. By using the Helmholtz decomposition, we reduce the initial-boundary value problem for the time domain Navier equation to a coupled initial-boundary value problem for wave equations, and prove the uniqueness of the solution for the coupled problem by employing the energy method. The retarded single layer potential is introduced to establish a set of coupled boundary integral equations, and uniqueness is discussed for the solution of these boundary integral equations. Based on the convolution quadrature method for time discretization, the coupled boundary integral equations are reformulated into a system of boundary integral equations in the s-domain, and then a convolution quadrature based nonlinear integral equation method is proposed for the inverse problem. Numerical experiments are presented to show the feasibility and effectiveness of the proposed method.
Finite temperature mean-field theory with intrinsic non-Hermitian structures for Bose gases in optical lattices
Authors: He Liang , Yi Su
Published: February 2022

We reveal a divergent issue associated with the mean-field theory for Bose gases in optical lattices constructed by the widely used straightforward mean-field decoupling of the hopping term, where the corresponding mean-field Hamiltonian generally assumes no lower energy bound once the spatial dependence of the mean-field superfluid (SF) order parameter is taken into account. Via a systematic functional integral approach, we solve this issue by establishing a general finite temperature mean-field theory that can treat any possible spatial dependence of the order parameter without causing the divergent issue. Interestingly, we find the theory generally assumes an intrinsic non-Hermitian structure that originates from the indefiniteness of the hopping matrix of the system. Within this theory, we develop an efficient approach for investigating the physics of the system at finite temperature, where properties of the system can be calculated via straightforward investigation on the saddle points of an effective potential function for the order parameter. We illustrate our approach by investigating the finite temperature SF transition of Bose gases in optical lattices. Since the underlying finite temperature mean-field theory is quite general, this approach can be straightforwardly applied to investigate the finite temperature properties of related systems with phases possessing complex spatial structures.
Tellurite glass based optical fiber for the investigation of supercontinuum generation and nonlinear properties
Authors: Amin Ruhul , Abdulrazak Lway Faisal , Tahhan Shaymaa R , Mohammadd Noor , Ahmed Kawsar , Bui Francis M , Ibrahim Sobhy M
Published: February 2022

This manuscript introduces a unique tellurite core-based photonic crystal fiber (PCF) with silica clad and circular air holes, which manifests highly birefringent and non-linear characteristics. Several optical features, such as birefringence (Br), nonlinear coefficients (NLC), dispersion (D), confinement loss (CL), material loss, etc are thoroughly analyzed and explored by applying the finite element method (FEM). The simulated outcomes validate that by optimizing the formation of the cladding region, a large NLC of

7650

W

−
1

Km

−
1

,

as well as an ultra-high Br of

11.2810

−
2

and zero-dispersion can be accomplished in the offered PCF design at 1.56 μm wavelength. Moreover, the evaluated findings indicate that the stated fiber structure is capable of generating a wide supercontinuum spectrum spanning from

943

to

8038

nm

when augmented with a

4.5

kW

input power and a pulse duration of

20

f
s
.

Calculations and analyses have been carried out on the effects of higher-order dispersion co-efficients, pulse length and input power on spectrum broadening. The advanced PCF design will be a suitable candidate for practical applications in numerous fields, including bio photonics, biomedical imaging, biosensing, spectroscopy and ultra-broadband signal amplification, etc.
Spatial curvature and large scale Lorentz violation *
Authors: Li Jing , Zhou Yongxiang , Xue Xun
Published: February 2022

The tension between the Hubble constant values obtained from local measurements and cosmic microwave background (CMB) measurements has motivated us to consider the cosmological model beyond ΛCDM. We investigate the cosmology in the large scale Lorentz violation model with a non-vanishing spatial curvature. The degeneracy among spatial curvature, cosmological constant, and cosmological contortion distribution makes the model viable in describing the known observational data. We obtain some constraints on the spatial curvature by comparing the relationship between measured distance modulus and red-shift with the predicted one, the evolution of matter density over time, and the evolution of effective cosmological constant. The implications of the large scale Lorentz violation model with the non-vanishing spatial curvature under these constrains are discussed.
Effect of passive metallic layers on muon energy estimation by means of deflection angle for muon scattering tomography: a comparative study based on GEANT4 simulations
Authors: Topuz A.I. , Kiisk M. , Giammaco A. , Mägi M.
Published: February 2022

In the tomographic configurations based on the muon scattering, the angular variation with respect to the kinetic energy indirectly brings forth the ability to coarsely predict the kinetic energy by using the deflection angle owing to the detector layers. Nevertheless, the angular deviation due to the detector components is expected to be minuscule in addition to a relatively high uncertainty in the case of the plastic scintillators. In the present study, we contrast our current tomographic prototype, which consists of the detector layers manufactured from polyvinyl toluene besides a detector accuracy of 1 mrad, with an alternative hodoscope scheme containing stainless steel layers by aiming to investigate the three-group energy structure. Initially, we determine the average deflection angles together with the corresponding standard deviations for our present setup as well as for the alternative scheme by means of the GEANT4 simulations. In the second place, we express a brace of misclassification probabilities founded on the standard deviations where the first procedure assumes a linear finite approximation, whereas the latter approach rests on a positively defined modified Gaussian distribution. Upon our simulation results, we demonstrate that the introduced stainless steel layers in the proposed hodoscope setup do not only serve to augment the average deflection angles, but they also diminish the misclassification probabilities, therewith reducing the classification uncertainty apart from an improved detection performance.
Ultrashort Pulse Reflectometry (USPR) diagnostic for EAST
Authors: Domier C.W. , Zhu Y. , Pereira R.J. , Steer-Furderer J. , Li X. , Chen R. , Xu G. , Sun P. , Luhmann N.C.
Published: February 2022

Ultrashort Pulse Reflectometry (USPR) is a plasma diagnostic technique involving the propagation of ultrashort duration (∼few nsec) chirps which contain frequency components spanning large portions of the plasma density profile. Upon reflection, each frequency component reflects from a distinct density layer. The reflected wave packet is down-converted and passed through a multi-channel filter bank, with time-of-flight (TOF) measurements made on each of the filtered wave packets which are then used to reconstruct the electron density profile. Applied previously to the Sustained Spheromak Physics Experiment, UC Davis is updating this technique with higher power (>10X) sources, enhanced channel counts, and high speed customized TOF electronics. A 32 channel USPR system is being developed for the Experimental Advanced Superconducting Tokamak (EAST) device with frequencies spanning 52 to 92 GHz, reflecting from the right-hand plasma cut-off layer. The system will employ three monostatic transmit/receive horns each covering a different waveguide band. Each of the two higher frequency bands will have 8 distinct frequency channels, with the lowest frequency band, spanning 52 to 65 GHz, to have 16 receiver channels to better resolve the EAST scrape-off layer. With a pulse repetition rate of 1 MHz and simultaneous acquisition of all 32 TOF signals, electron density profiles may be obtained with time resolutions of as short as 3–6 µsec.
Multi-channel front-end ASIC for a 3D position-sensitive detector
Authors: Pinaroli G. , Herrmann S. , Miryala S. , Manthena V. , Deptuch G.W. , Carini G.A. , Bolotnikov A.E. , Dellapenna A. , Raguzin E. , Fried J. , Deane C.R. , Brown C.A. , Christian J. , Cirignano L. , Kargar A. , Kim H. , Shah K.S. , Squillante M. , Squillante M.S. , Weststrate E. , Valente A.J. , Koslowsky M.R. , Miller A.L. , Smith M.B.
Published: February 2022

Arrays of 3D position-sensitive detectors (3DPSD), operating at room temperature and using cadmium zinc telluride (CZT) and thallium bromide (TIBr) sensors, are suitable for gamma-ray spectrometry in many applications. One detector configuration, the 3D position-sensitive Virtual Frisch-Grid detector (VFG), is particularly advantageous for integrating into large area arrays. The signals generated inside each detector of the array are captured with the anode, cathode and four pads that enable the reconstruction of the position and energy of the ionizing interaction by measurements of amplitude and timing of the signals. For these applications, a low-noise front-end ASIC has been developed, capable of processing bipolar signals (needed because of AC-coupling of certain electrodes). The ASIC can be coupled to an ADC in order to form a compound “waveform digitizer” capable of post-processing the analog signals and determining amplitude and timing information. This paper describes a 32-channel front-end ASIC that is suitable for reading out a 3 × 3 or 4 × 4 element matrix in the VFG configuration. Each channel is composed of a low-noise charge amplifier with an adaptive continuous reset feedback circuit suitable for both positive and negative charge, a first order shaper and a single-to-differential converter output stage. Voltage and current references are all internally generated by 10-bit DACs and the chip is fully controllable with the I2C communication protocol. The readout channel response has been verified using the implemented injection circuit. Linear behavior up to ∼75 ke± with the gain of ∼80 mV/fC, and up to ∼200 ke± with the gain of ∼30 mV/fC was demonstrated. In conclusion, the first test result waveforms using a 137Cs radioactive source on a 5 × 5 × 12 mm3 TIBr crystal are reported.
A Neural-Network-defined Gaussian Mixture Model for particle identification applied to the LHCb fixed-target programme
Authors: Graziani G. , Anderlini L. , Mariani S. , Franzoso E. , Pappalardo L.L. , di Nezza P.
Published: February 2022

Particle identification in large high-energy physics experiments typically relies on
classifiers obtained by combining many experimental observables. Predicting the probability density function (pdf) of such classifiers in the multivariate space covering the relevant experimental features is usually challenging.
The detailed simulation of the detector response from first principles
cannot provide the reliability needed for the most precise physics measurements.
Data-driven modelling is usually preferred, though sometimes limited by the available data size and different coverage of the feature space by the control channels.
In this paper, we discuss a novel approach to the modelling of particle
identification classifiers using machine-learning techniques. The marginal pdf of the classifiers is described with a Gaussian Mixture Model, whose parameters are predicted by Multi Layer Perceptrons trained on calibration data. As a proof of principle, the method is applied to the data acquired by the LHCb experiment in its fixed-target configuration. The model is trained on a data sample of proton-neon collisions and applied to smaller data samples of proton-helium and proton-argon collisions collected at different centre-of-mass energies. The method is shown to perform better than a detailed simulation-based approach, to be fast and suitable to be applied to a large variety of use cases.
Understanding the effect of aging treatment on the electrical properties of Al-4Cu (wt.%) alloy
Authors: Zhu Langjie , Wang Yu , Mao Jian
Published: February 2022

Binary Al–Cu alloy has always been used to illustrate the phenomenon of precipitation hardening. Meanwhile, Al–Cu alloy has good heat resistance and is a potential heat-resistant conductor material, but there is not much research work on its electrical properties. In this work, the residual resistivity variation of Al-4Cu alloy at different aging stages was investigated. At the aging temperature of 160 °C, the residual resistivity of the Al-4Cu alloy decreases with the longer aging time, and it decreases rapidly in the early stage and slowly in the later stage, mainly due to the precipitation of solid solution Cu atoms and the interface electron scattering effect of different precipitates. In the early stage, massive precipitation of Cu atoms from the matrix can effectively reduce the crystal lattice distortion of Al matrix and significantly decrease the residual resistivity. Specifically, the residual resistivity of Al-4Cu alloy that aged at 160 °C for 13 h is 3.353 μΩ·cm, which is only 82.6% of that in the supersaturated solid solution state. In later stage of aging, the main change is the evolution of the precipitated phase, i.e., the gradual disruption of the coherent relationship between the second phase and the Al matrix. And the coherency-strain fields decrease gradually, which is also beneficial in decreasing the residual resistivity. The results show that Al–Cu alloys can also be a potential heat-resistant conductor material for the power transmission industry.
Research on damping performance of elastomer/carbon fiber epoxy composite
Authors: Tengfei Qin , Jinsheng Liu , Xing Wei , Bin Fu , Shanyong Xuan , Zhiyuan Wang
Published: February 2022

The preparation method of the composite material with damping layer and the influence of the position of the single-layer damping layer in the composite material on the damping coefficient have not been studied in detail. In this paper, the most commonly used composite molding methods, the hot autoclave and hot patch method, to manufacture elastomer/carbon fiber reinforced epoxy resin (elastomer/CFER) composites. Then, the effects of the manufacturing method and the position of the elastomer on the short beam shear strength and damping performance of the co-cured composite were studied. The novel results show that the composite manufactured by the hot autoclave has high shear strength, but the damping factor of the composite is relatively weak. The addition of the damping layer has little effect on the shear strength of the composites of the hot patch instrument, and the damping factor of the composites with an elastic layer in the middle can reach 0.0683, which is 4.1 times that of the composites without the damping layer, and 2.5 times of the composites with an elastic layer in the middle of the hot autoclave manufacturing.
Semiclassical resonance asymptotics for the delta potential on the half line
Authors: Datchev Kiril , Malawo Nkhalo
Published: February 2022

We compute resonance width asymptotics for the delta potential on the half-line, by deriving a formula for resonances in terms of the Lambert W function and applying a series expansion. This potential is a simple model of a thin barrier, motivated by physical problems such as quantum corrals and leaky quantum graphs.
On the tangent space to the Hilbert scheme of points in 𝐏³
Authors: Ramkumar Ritvik , Sammartano Alessio
Published: February 2022

In this paper we study the tangent space to the Hilbert scheme

H
i
l
b

d

P

3

\mathrm {Hilb}^d \mathbf {P}^3

, motivated by Haiman’s work on

H
i
l
b

d

P

2

\mathrm {Hilb}^d \mathbf {P}^2

and by a long-standing conjecture of Briançon and Iarrobino [J. Algebra 55 (1978), pp. 536–544] on the most singular point in

H
i
l
b

d

P

n

\mathrm {Hilb}^d \mathbf {P}^n

. For points parametrizing monomial subschemes, we consider a decomposition of the tangent space into six distinguished subspaces, and show that a fat point exhibits an extremal behavior in this respect. This decomposition is also used to characterize smooth monomial points on the Hilbert scheme. We prove the first Briançon-Iarrobino conjecture up to a factor of

4
3

\frac {4}{3}

, and improve the known asymptotic bound on the dimension of

H
i
l
b

d

P

3

\mathrm {Hilb}^d \mathbf {P}^3

. Furthermore, we construct infinitely many counterexamples to the second Briançon-Iarrobino conjecture, and we also settle a weaker conjecture of Sturmfels in the negative.
Modulating RhoA effectors induces transitions to oscillatory and more wavelike RhoA dynamics in Caenorhabditis elegans zygotes
Authors: Yao Baixue , Donoughe Seth , Michaux Jonathan , Munro Edwin
Published: February 2022

In this paper, Yao et al. use a combination of live imaging and quantitative image analysis to explore how modulating actin network dynamics and contractility can tune spatiotemporal patterns of RhoA activity in early Caenorhabditis elegans embryos.
DynaMorph: self-supervised learning of morphodynamic states of live cells
Authors: Wu Zhenqin , Chhun Bryant B. , Popova Galina , Guo Syuan-Ming , Kim Chang N. , Yeh Li-Hao , Nowakowski Tomasz , Zou James , Mehta Shalin B.
Published: February 2022

A cell’s function depends on its dynamic architecture. There is growing interest in modern cell biology for methods enabling the automated analysis of morphodynamics of live cells. Here we demonstrate the power of label-free live cell imaging and self-supervised deep learning for automated analysis of complex dynamics of human microglia.
Impact of a pharmacist-led telehealth oral chemotherapy clinic
Authors: Mathur Anupama D , Maiers Tristan A , Andrick Benjamin J
Published: February 2022

Purpose

Oral oncolytics come with significant concerns of noncompliance due to complex regimens, adverse effects, and high overall costs. The Geisinger Oral Chemotherapy Clinic is a fully telephone-based medication therapy disease management (MTDM) program designed to integrate pharmacists as advanced practitioners in hematology/oncology clinics for comanagement of oral chemotherapy.

To date, Geisinger has 11 oncology clinics and 3 full-time pharmacists designated to the management of oral chemotherapy. Pharmacists receive referrals for comanagement of patients starting oral oncolytics. Under a collaborative practice agreement, they can order laboratory tests as well as supportive care medications and refills. Pharmacists review planned therapies, perform medication reconciliations, and provide medication counseling. Once treatment has been initiated, pharmacists contact patients for laboratory and toxicity assessments. The clinic incorporates the use of customized smart data elements within the electronic medical record to collect data regarding pharmacist interventions and time allocations in the clinic. As of March 31, 2021, the clinic was actively following approximately 1,100 patients, resulting in an average of 80 to 90 encounters per day for new referrals, chemotherapy education, and laboratory and toxicity assessments. Approximately 2,113 patients were followed from December 1, 2019, to March 31, 2021, with 46,929 interventions documented.

Conclusion

By obtaining provider buy-in for pharmacy services, acquiring enough personnel resources to meet the needs of the growing patient population and respective therapies, and proper utilization of technology, the program has thrived, allowing for increased provider and patient satisfaction. Future goals include expanding collection of pharmacist intervention metrics and analysis of patient perceptions of services provided by the clinic.
Leaf photosynthesis is positively correlated with xylem and phloem areas in leaf veins in rice (Oryza sativa) plants
Authors: Huang Guanjun , Shu Yu , Peng Shaobing , Li Yong
Published: February 2022

Background and Aims

Leaf structure is an important determinant of leaf photosynthesis; however, the impacts of leaf structural traits on gas exchange parameters are still not fully understood. In the present study, 11 rice genotypes were grown in pots to investigate the influence of leaf structural traits on leaf photosynthesis and hydraulic conductance (Kleaf).

Methods

In this study, leaf photosynthetic rate (A), stomatal conductance (gs), mesophyll conductance and Kleaf were measured. In addition, leaf structural traits including leaf thickness (LT), leaf mass per area and leaf xylem and phloem sizes were also measured to investigate their impacts on rice photosynthesis.

Key Results

We found that the total area of xylem conduits per major vein (Xmajor), leaf phloem area per minor vein (Pminor) and LT were positively correlated with Kleaf, gs and A. The path analysis suggested that, however, only Pminor had a direct impact on A; Xmajor had an indirect impact on A via gs and Pminor, while LT did not show any direct or indirect impact on A.

Conclusion

This study highlighted the importance of manipulations in Xmajor and Pminor, two previously overlooked leaf traits, to improve leaf photosynthesis in rice plants.
Improve consensus partitioning via a hierarchical procedure
Authors: Gu Zuguang , Hübschmann Daniel
Published: February 2022

Consensus partitioning is an unsupervised method widely used in high-throughput data analysis for revealing subgroups and assigning stability for the classification. However, standard consensus partitioning procedures are weak for identifying large numbers of stable subgroups. There are two major issues. First, subgroups with small differences are difficult to be separated if they are simultaneously detected with subgroups with large differences. Second, stability of classification generally decreases as the number of subgroups increases. In this work, we proposed a new strategy to solve these two issues by applying consensus partitioning in a hierarchical procedure. We demonstrated hierarchical consensus partitioning can be efficient to reveal more meaningful subgroups. We also tested the performance of hierarchical consensus partitioning on revealing a great number of subgroups with a large deoxyribonucleic acid methylation dataset. The hierarchical consensus partitioning is implemented in the R package cola with comprehensive functionalities for analysis and visualization. It can also automate the analysis only with a minimum of two lines of code, which generates a detailed HTML report containing the complete analysis. The cola package is available at https://bioconductor.org/packages/cola/.
Learning deep features and topological structure of cells for clustering of scRNA-sequencing data
Authors: Wang Haiyue , Ma Xiaoke
Published: February 2022

Single-cell RNA sequencing (scRNA-seq) measures gene transcriptome at the cell level, paving the way for the identification of cell subpopulations. Although deep learning has been successfully applied to scRNA-seq data, these algorithms are criticized for the undesirable performance and interpretability of patterns because of the noises, high-dimensionality and extraordinary sparsity of scRNA-seq data. To address these issues, a novel deep learning subspace clustering algorithm (aka scGDC) for cell types in scRNA-seq data is proposed, which simultaneously learns the deep features and topological structure of cells. Specifically, scGDC extends auto-encoder by introducing a self-representation layer to extract deep features of cells, and learns affinity graph of cells, which provide a better and more comprehensive strategy to characterize structure of cell types. To address heterogeneity of scRNA-seq data, scGDC projects cells of various types onto different subspaces, where types, particularly rare cell types, are well discriminated by utilizing generative adversarial learning. Furthermore, scGDC joins deep feature extraction, structural learning and cell type discovery, where features of cells are extracted under the guidance of cell types, thereby improving performance of algorithms. A total of 15 scRNA-seq datasets from various tissues and organisms with the number of cells ranging from 56 to 63 103 are adopted to validate performance of algorithms, and experimental results demonstrate that scGDC significantly outperforms 14 state-of-the-art methods in terms of various measurements (on average 25.51% by improvement), where (rare) cell types are significantly associated with topology of affinity graph of cells. The proposed model and algorithm provide an effective strategy for the analysis of scRNA-seq data (The software is coded using python, and is freely available for academic https://github.com/xkmaxidian/scGDC).
The future of assessing bull fertility: Can the ‘omics fields identify usable biomarkers?
Authors: Klein Erin K , Swegen Aleona , Gunn Allan J , Stephen Cyril P , Aitken Robert John , Gibb Zamira
Published: February 2022

Breeding soundness examinations for bulls rely heavily on the subjective, visual assessment of sperm motility and morphology. Although these criteria have the potential to identify infertile males, they cannot be used to guarantee fertility or provide information about varying degrees of bull fertility. Male factor fertility is complex, and the success of the male gamete is not necessarily realized until well after the spermatozoon enters the oocyte. This paper reviews our existing knowledge of the bull’s contribution from a standpoint of the sperm’s cargo and the impact that this can have on fertilization and the development of the embryo. There has been a plethora of recent research characterizing the many molecular attributes that can affect the functional competence of a spermatozoon. A better understanding of the molecular factors influencing fertilization and embryo development in cattle will lead to the identification of biomarkers for the selection of bulls of superior fertility, which will have major implications for livestock production. To see this improvement in reproductive performance, we believe incorporation of modern technology into breeding soundness examinations will be necessary—although many of the discussed technologies are not ready for large-scale field application. Each of the ‘omics fields discussed in this review have shown promise for the identification of biomarkers of fertility, with certain families of biomarkers appearing to be better suited to different evaluations throughout a bull’s lifetime. Further research is needed for the proposed biomarkers to be of diagnostic or predictive value.