bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceived risk of HIV transmission by blood transfusion among gay, bisexual, and other men who have sex with men (gbMSM) in Australia
Authors: Gahan Luke , Seed Clive R. , Hammoud Mohamed A. , Prestage Garrett , Hoad Veronica C. , Kaldor John M.
Published: June 2023

Background

In Australia, men who have sex with men (MSM) are deferred from blood donation for 3 months from last sexual contact. Internationally, deferral policies for MSM are evolving in the direction of expanded inclusivity in response to community expectations. To inform future policy options, we assessed perceptions of the risk of HIV transmission from blood transfusion among Australian MSM.

Study Design and Methods

Flux is an online prospective cohort of Australian gay and bisexual men (cis or trans, regardless of their sexual history) and other men who have had sex with men (gbMSM). We included questions on blood donation rules, window period (WP) duration, infectivity of blood from people with HIV on treatment and attitudes to more detailed questioning of sexual practices in the regular survey of Flux participants and conducted a descriptive analysis of responses.

Results

Of 716 Flux participants in 2019, 703 responded to the blood donation questions. The mean age was 43.7 years (SD 13.6 years). Overall, 74% were willing to confidentially respond to specific sexual behavior questions, such as the last time they had sex and the type of sex they had, in order to be considered eligible to donate blood. The majority (92%) of participants correctly assessed the duration of the WP as less than 1 month. When asked whether transfusion of blood from a donor with HIV and an undetectable viral load could transmit HIV, just under half (48%) correctly said yes.

Conclusion

Our study suggests Australian gbMSM are generally comfortable with answering more detailed questions regarding sexual activity during the assessment to donate, indicating they would do so honestly. gbMSM are knowledgeable about the WP duration, important for their ability to correctly self‐assess their HIV risk. However, half of participants incorrectly assessed the transmissibility by blood transfusion from an HIV positive person with an undetectable viral load, suggesting the need for a targeted education campaign.
The “Claw Sign” may aid in axial localization in cases of peripherally located canine glioma on MRI
Authors: Glamann Samantha , Jeffery Nicholas D. , Levine Jonathan M. , Gremillion Christine L. , Gilmour Lindsey J. , Boudreau C. Elizabeth , Hecht Silke , Griffin John F.
Published: June 2023

The “claw sign” is a radiographic sign studied in human imaging to determine if a mass arises from a solid structure or organ versus a close adjacent location, resulting in distortion of the outline of an organ. We investigated its utility in characterizing MRI axial localization of peripherally located intracranial glioma versus meningioma, due to their overlap in MRI appearance. This retrospective, secondary analysis, cross‐sectional study aimed to report the sensitivity, specificity, and inter‐ and intraobserver variabilities using kappa statistics, hypothesizing that the claw sign will have strong inter‐ and intraobserver agreement (κ > 0.8). Dogs with a histologically confirmed diagnosis of peripherally located glioma or meningioma and available 3T MRI data were retrieved from medical record archives from 2009 to 2021. A total of 27 cases, 11 glioma and 16 meningioma, were included. The postcontrast T1‐weighted images were provided to five blinded image evaluators in two separate randomized sessions separated by a 6‐week wash out period. Prior to the first evaluation, evaluators were provided with a training video and set of training cases for the “claw sign,” which were excluded from the study. Evaluators were asked to rate cases as “positive,” “negative,” or “indeterminate” for the “claw sign.” The sensitivity and specificity for the “claw sign” for the first session were 85.5% and 80%, respectively. The interobserver agreement for identifying the “claw sign” was moderate (κ = 0.48), and the intraobserver agreement across the two sessions was substantial (κ = 0.72). These findings indicate the claw sign is supportive but not pathognomonic for intra‐axial localization in cases of canine glioma on MRI.
Contrast‐enhanced CT predictors of lymph nodal metastasis in dogs with oral melanoma
Authors: Menghini Timothy L. , Schwarz Tobias , Dancer Sumari , Gray Calum , MacGillivray Tom , Blacklock Kelly L. Bowlt
Published: June 2023

Canine oral melanoma (OM) has highly aggressive behavior, with frequent local metastasis. Computed tomography 3D volumetric analysis is an accurate predictor of lymph node (LN) metastasis of oral cancers in humans but whether this is true for dogs with OM is unknown. In this retrospective observational study, CT imaging was used to assess mandibular and retropharyngeal lymphocenter (LC) changes in dogs with nodal metastatic (n = 12) and non‐metastatic (n = 10) OM, then these findings were compared with those of healthy control dogs (n = 11). Using commercial software (Analyze, Biomedical Imaging Resource), lymphocenters were defined as regions of interest. LC voxels, area (mm2), volume (mm3), and degree of attenuation (HU) were compared between groups. Mandibular lymphocenter (MLC) metastasis was present in 12 of 22 (54.5%) dogs; no dogs had confirmed retropharyngeal lymphocenter (RLC) metastasis. Mandibular lymphocenter volume was significantly different between positive and negative LCs (median 2221 and 1048 mm3, respectively, P = 0.008), and between positive and control LCs (median 880 mm3, P < 0.01). There was no evidence of a significant difference in voxel number or attenuation between groups. Mandibular lymphocenter volume moderately discriminated for metastatic status (AUC 0.754 [95% CI = 0.572–0.894, P = 0.02]), with a positive predictive value of 57.1% (95% CI = 0.389–0.754). Adjusting for patient weight did not improve discrimination (AUC = 0.659 (95% CI = 0.439–0.879, P = 0.13]). In conclusion, these findings suggest 3D CT volume measurement of MLC can predict nodal metastasis in dogs with OM and shows promise but further research, perhaps in combination with other modalities, is required to improve accuracy.
Hyperbolicity and uniformly Lipschitz affine actions on subspaces of L1$L^1$
Authors: Vergara Ignacio
Published: June 2023

We show that every hyperbolic group has a proper uniformly Lipschitz affine action on a subspace of an space. We also prove that every acylindrically hyperbolic group has a uniformly Lipschitz affine action on such a space with unbounded orbits. Our main tools are the ‐bicombings on hyperbolic groups constructed by Mineyev and the characterisation of acylindrical hyperbolicity in terms of actions on quasi‐trees by Balasubramanya.
Geodesics in the space of relatively Kähler metrics
Authors: Hallam Michael
Published: June 2023

We derive the geodesic equation for relatively Kähler metrics on fibrations and prove that any two such metrics with fibrewise constant scalar curvature are joined by a unique smooth geodesic. We then show convexity of the log‐norm functional for this setting along geodesics, which yields simple proofs of Dervan and Sektnan's uniqueness result for optimal symplectic connections and a boundedness result for the log‐norm functional. Next, we associate to a fibration degeneration a unique geodesic ray defined on a dense open subset. Calculating the limiting slope of the log‐norm functional along a globally defined smooth geodesic ray, we prove that fibrations admitting optimal symplectic connections are polystable with respect to a large class of fibration degenerations that are smooth over the base. We give examples of such degenerations in the case of projectivised vector bundles and isotrivial fibrations.
A pretentious proof of Linnik's estimate for primes in arithmetic progressions
Authors: Sachpazis Stelios
Published: June 2023

In the present paper, the author adopts a pretentious approach and recovers an estimate obtained by Linnik for the sums of the von Mangoldt function Λ on arithmetic progressions. It is the analogue of an estimate that Linnik established in his attempt to prove his celebrated theorem concerning the size of the smallest prime number of an arithmetic progression. Our work builds on ideas coming from the pretentious large sieve of Granville, Harper, and Soundararajan and it also borrows insights from the treatment of Koukoulopoulos on multiplicative functions with small averages.
Small Female Occupant Response in Reclined and Upright Seated Postures in Frontal Impacts
Authors: Somasundaram Karthik , Hauschild Hans , Driesslein Klaus , Pintar Frank A.
Published: June 2023

The objective of this study was to compare the kinematics of the head-neck, torso, pelvis, and lower extremities and document injuries and their patterns to small female occupants in frontal impacts with upright and reclined postures using an experimental model. Six postmortem human surrogates (PMHS) with a mean stature of 154 ± 9.0 cm and mass of 49 ± 12 kg were equally divided between upright and reclined groups (seatback: 25 deg and 45 deg), restrained by a three-point integrated belt, positioned on a semirigid seat, and exposed to low and moderate crash velocities (15 km/h and 32 km/h respectively). The response between the upright and reclined postures was similar in magnitude and curve morphology. While none of the differences were statistically significant, the thoracic spine demonstrated increased downward (+Z) displacement, and the head demonstrated an increased horizontal (+X) displacement for the reclined occupants. In contrast, the upright occupants showed a slightly increased downward (+Z) displacement at the head, but the torso displaced primarily along the +X direction. The posture angles between the two groups were similar at the pelvis and different at the thorax and head. At 32 km/h, both cohorts exhibited multiple rib failure, with upright specimens having a greater number of severe fractures. Although MAIS was the same in both groups, the upright specimens had more bi-cortical rib fractures, suggesting the potential for pneumothorax. This preliminary study may be useful in validating physical (ATDs) and computational (HBMs) surrogates.
Statistical Shape and Bone Property Models of Clinical Populations as the Foundation for Biomechanical Surgical Planning: Application to Shoulder Arthroplasty
Authors: Sharif-Ahmadian Azita , Beagley Aren , Pearce Claire , Saliken David , Athwal George S. , Giles Joshua W.
Published: June 2023

This work developed, validated, and compared statistical shape, statistical intensity, and statistical shape and intensity models (SSMs, SIMs, SSIMs) of scapulae from a clinical population. SSMs efficiently describe bone shape variation while SIMs describe bone material property variation, and SSIM's combine description of both variables. This work establishes these models' efficacy and whether they can be used in surgical planning. Models were developed using shoulder arthroplasty data of patients with bone erosion, which is challenging to treat and would benefit from improved surgical planning. Models were created using previously validated nonrigid registration and material property assignment processes that were optimized for scapula characteristics. The models were assessed using standard metrics, anatomical measurements, and correlation analyses. The SSM and SIM specificity and generalization error metrics were 3.4 mm and <1 mm and 184 HU and 156 HU, respectively. The SSIM did not achieve the same level of performance as the SSM and SIM in this study (e.g., shape generalization: SSIM—2.2 mm versus SSM—<1 mm). Anatomical correlation analysis showed that the SSM more effectively and efficiently described shape variation compared to the SSIM. The SSM and SIM modes of variation were not strongly correlated (e.g., rmax = 0.56 for modes explaining ≤2.1% of variance). The SSIM is outperformed by the SSM and SIM and the latter two are not strongly correlated; therefore, using the SSM and SIM in conjunction will generate synthetic bone models with realistic characteristics and thus can be used for biomechanical surgical planning applications.
Novel Calculation Method for Windage Power Loss of Double-Helical Gear Transmission
Authors: Yang Jin , Lin Tengjiao
Published: June 2023

This paper presents a novel fast calculation method for windage power loss (WPL) of the meshing double-helical gear pair. Firstly, based on the basic equations of fluid mechanics and computational fluid dynamics simulation method, the calculation method for single-tooth windage torque at the zone of meshing/nonmeshing is established; Secondly, the WPL of meshing gear pair with different gear parameters and operating conditions are obtained according to the single-tooth windage torque during a rotation period and the windage torque at the end faces, and the accuracy of the proposed WPL method is verified through the WPL test measurement and simulation; Finally, the effect of gear parameters and operating conditions on the WPL is studied.
Simulation of Micro-Powder Injection Molding Using a Dynamic Mesh Approach
Authors: Islam Sk Tanbir , Samanta Sudip K. , Das Santanu , Chattopadhyay Himadri
Published: June 2023

Powder injection molding (PIM) is capable of manufacturing complex small components out of metals and ceramics. With increasing market demand micropowder injection molding (micro-PIM) is improving rapidly which calls for improved numerical models of different stages of PIM. The injection stage is quite important as different defects may occur during injection that cannot be eliminated in the subsequent processes. Injection pressure and velocity are critical controlling parameters to manufacture a defect-free component. However, in most of the simulations, either injection pressure or injection velocity is taken as a constant value, while in reality, the injection molding of the piston moves at different speeds, and injection pressure and velocity change accordingly. In the experimental part of the present work, the piston movement is tracked using a high-speed camera which was mimicked in mold filling simulation of an alumina feedstock, considering the Dynamic Mesh approach. The solution of the full Navier–Stokes equation in an Eulerian-multiphase framework is used to simulate the mold filling where the secondary phase is air that is displaced by moving melt front. Additionally, a scalar equation was used to account for the liquid fraction of the feedstock. It is further demonstrated that the proposed model provides insight into the fluid-dynamic aspect of the mold-filling process.
The Relationship Between Imbalance Symptom and Cardiac Pulsation Induced Mechanical Strain in the Brainstem and Cerebellum for Chiari Malformation Type I
Authors: Al Samman Mohamad Motaz F. , Ibrahimy Alaaddin , Nwotchouang Blaise Simplice Talla , Oshinski John N. , Barrow Daniel L. , Allen Philip A. , Amini Rouzbeh , Bhadelia Rafeeque A. , Loth Francis
Published: June 2023

Chiari malformation Type I (CMI) is known to have an altered biomechanical environment for the brainstem and cerebellum; however, it is unclear whether these altered biomechanics play a role in the development of CMI symptoms. We hypothesized that CMI subjects have a higher cardiac-induced strain in specific neurological tracts pertaining to balance, and postural control. We measured displacement over the cardiac cycle using displacement encoding with stimulated echoes magnetic resonance imaging in the cerebellum, brainstem, and spinal cord in 37 CMI subjects and 25 controls. Based on these measurements, we computed strain, translation, and rotation in tracts related to balance. The global strain on all tracts was small (<1%) for CMI subject and controls. Strain was found to be nearly doubled in three tracts for CMI subjects compared to controls (p < 0.03). The maximum translation and rotation were ∼150 μm and ∼1 deg, respectively and 1.5–2 times greater in CMI compared to controls in four tracts (p < 0.005). There was no significant difference between strain, translation, and rotation on the analyzed tracts in CMI subjects with imbalance compared to those without imbalance. A moderate correlation was found between cerebellar tonsillar position and strain on three tracts. The lack of statistically significant difference between strain in CMI subjects with and without imbalance could imply that the magnitude of the observed cardiac-induced strain was too small to cause substantial damage to the tissue (<1%). Activities such as coughing, or Valsalva may produce a greater strain.
Sono-palpation and sono-Tinel in musculoskeletal ultrasound examination: use all “sono-senses”. A systematic review
Authors: Pirri Carmelo , Pirri Nina , Stecco Carla , Macchi Veronica , Porzionato Andrea , De Caro Raffaele , Özçakar Levent
Published: June 2023

Flexibility and dynamic perspective of ultrasound imaging allow for a targeted/focused examination, yielding extra find-ings. Sonopalpation – also referred as sono-Tinel for nerves – is one of those particular features of ultrasound examination whereby the ultrasound probe is actively ‘manipulated’. It is paramount to ascertain the painful structure/pathology during the evaluation of a patient and it is not possible with other imaging techniques other than ultrasonography. In this aspect, the cur-rent review aims to provide an analysis of the literature regarding the use of sonopalpation for clinical and research purposes respectively.
Supplemental Material: Andean-type, bivergent crustal shortening in the Rinkian orogen: New constraints on the tectonic evolution of Laurentia–West Greenland in the Paleoproterozoic
Authors: Grocott John , al. et
Published: June 2023

File S1: Structural map for the north Rinkian FTB, the PIC, and the south Rinkian FTB on Nunavik (Svartenhuk Halvø) and Inngia; file contains structural data layers additional to Figure 3 (Adobe layered .pdf file). File S2: Analytical methods (.pdf file). File S3: Table S1, U-Th-Pb data from zircons (.xlsx file). File S4: Table S2, U-Th-Pb data from monazites (.xlsx file).
Spatiotemporal variation in pup abundance and preweaning survival of harbour seals (Phoca vitulina) in the St. Lawrence Estuary, Canada
Authors: Renaud Limoilou-Amélie , Pigeon Gabriel , Van de Walle Joanie , Bordeleau Xavier , Hammill Mike O. , Pelletier Fanie
Published: June 2023

Marine mammal populations worldwide greatly benefitted from conservation measures put in place since the 1970s following overexploitation, and many pinniped populations have recovered. However, threats due to bycatch, interspecific interactions or climate change remain, and detailed knowledge on vital rates, population dynamics, and their responses to environmental changes is essential for efficient management and conservation of wild populations. In this study, we quantified pup abundance and survival of individually marked harbour seal ( Phoca vitulina Linnaeus, 1758) pups during the preweaning period at Bic Island and Métis sites in the St. Lawrence Estuary from 1998 to 2019. We used mark-recapture models to evaluate competing hypotheses regarding variation in daily preweaning survival rates and capture probability during the pups’ first 30 days of life. Pup abundance increased from 76 [95% CI: 59, 101] to 323 [95% CI: 233, 338] in the past two decades at Bic Island and from 66 [95% CI: 47, 91] to 285 [95% CI: 204, 318] at Métis. Preweaning survival was generally higher at Bic (0.73 [95% CI: 0.58, 0.82]) than at Métis (0.68 [95% CI: 0.52, 0.79]). We hypothesize that differences between habitats and human disturbance contribute to lower preweaning survival at Métis, but behavioural studies are needed to understand the impacts of disturbance on mother–pup interactions during the nursing period.
Predator–prey interactions between gleaning bats and katydids
Authors: ter Hofstede Hannah M. , Faure Paul A.
Published: June 2023

Bats are voracious predators of insects, and many insects have ears sensitive to the high-frequency echolocation calls of bats. Eared insects show a variety of defences when they detect bat echolocation calls. Professor Brock Fenton was an early contributor to the field of bat–insect interactions, inspiring many students to pursue investigations that have advanced our understanding of the relationship between predators and prey. Reflecting on the integrative nature of Dr. Fenton's research, this review highlights research on the evolutionary arms race between gleaning insectivorous bats and katydid prey. Studies on this system have enhanced the field of sensory ecology by illuminating how animal auditory systems can encode and distinguish between signals that overlap in their acoustic properties but have very different consequences for the listener (sex or death). These studies also inform us about the ecological and evolutionary selection pressures on signalers and receivers that can shape mate attraction and predator avoidance behaviour. In particular, many Neotropical katydids rely on preventative instead of reactive defences against gleaning bats, likely due to the regular presence of echolocation calls from non-gleaning bats that reduce the information content of predator cues. We conclude with suggestions for future research on these fascinating animals.
Poincaré metric of holomorphic foliations with non-degenerate singularities
Authors: Bacher François
Published: June 2023

Consider a Brody hyperbolic foliation [Formula: see text] with non-degenerate singularities on a compact complex manifold. We show that its leafwise Poincaré metric is transversally Hölder continuous with a logarithmic slope towards the singular set of [Formula: see text].
Numerical analysis of hydromagnetic micropolar squeezing flow lubricated between porous elliptical plates
Authors: Halambi Brinda , Hanumagowda B. N. , Kumar J. Santhosh , Khan Umair , Sherif El-Sayed M. , Chohan Jasgurpreet Singh , Shilpa B. , Pop Ioan
Published: June 2023

An attempt is made to analyze the effects of micropolar fluid squeezing film implementation between porous elliptical plates under the application of an external magnetic field. The appropriate improved hydromagnetic Reynolds equation governing the pressure distribution is acquired. The Reynolds equation is solved for lubrication features such as pressure distribution, load-carrying capacity and time-height relationships. It is noticed that a micropolar lubricant with a magnetic field may considerably impart a much-appreciated increase in load-carrying capacity, pressure distribution and response time compared to the classical case. Nevertheless, it is found that, as with the magnetic field, the larger values of the fluid gap number and the coupling number increase lubrication characteristics. Also, it is found that such a bearing cannot support a large number of lubrication characteristics because of the pores on the main path of fluid flow.
Computational investigation of combined solar chimney power plant with gas power plant in different working conditions
Authors: Mirzamohammad Amin , Yazdi Mohammad Eftekhari , Lavasani Arash Mirabdolah
Published: June 2023

Numerous studies have recently focused on enhancing the efficiency of solar chimney power plants (SCPP) and increasing their output power during periods of limited solar radiation. One such study proposes a novel solution: combining an SCPP with a gas power plant to create a hybrid power plant that generates power consistently, day and night. The system involves burying pipes underground and channeling the hot gas from the gas power plant through them, rather than releasing it into the atmosphere. This process increases the temperature of the soil beneath the canopy, which in turn raises the air temperature and the velocity of the air. The resulting decrease in air density leads to an increase in output power. Our results show that the performance of solar chimney of soil ground with buried pipe is about 30% higher than sand domain.
Phase synchronization in cryptocurrency network and its features
Authors: Ansarinasab Sheida , Ghassemi Farnaz , Nazarimehr Fahimeh , Ghosh Dibakar , Jafari Sajad
Published: June 2023

Investigating the time–frequency-based phase synchronization between nonstationary time series of the cryptocurrencies’ prices can be a suitable tool to reveal their complicated interactions at different frequencies. In this work, the phase synchronization between 25 cryptocurrencies with the highest capitalization from December 1, 2021 to June 1, 2022 is calculated using the phase-locking value method based on wavelet transform. Then, utilizing the graph theory, the cryptocurrency networks are constructed, and their topological features like path length (PL), clustering coefficient (CC) and node strength are evaluated in various frequencies. This research indicates a strong phase synchronization between the investigated cryptocurrencies, especially in low frequencies. Also, the networks’ high average CC and short PL compared to their equivalent regular and random networks display the small-worldness of the networks. We observe from the obtained results that Bitcoin, Ethereum and Binance currencies, among the most popular cryptocurrencies, have the highest average node strengths at different frequencies. Also, TRON shows the lowest CC and node strength among all currencies, representing its limited phase interaction with other currencies.
Deep Time-Aware Attention Neural Network for Sequential Recommendation
Authors: Hua Qiang , Chen Liyou , Dong Chunru , Li Pan , Zhang Feng
Published: June 2023

For click-through rate (CTR) prediction tasks, a good prediction performance can be obtained by full explorations of both user behavior and item behavior. Since user’s interests have a great influence on user’s behaviors, it is very important to learn users’ intrinsic interests according to their behaviors. User interests are not only diverse but also in dynamic change. However, the dynamics of user interests’ change are not fully taken into account by the majority of current CTR models. The latest sequential recommendation algorithm ignores the subjectivity of users when it uses a two-layer recurrent neural network to model the item behavior from the perspective of the evolution of items. In this work, we propose a recurrent neural network model called DTIAN (Deep Time-Aware Interest Attention Network) to address these issues. By leveraging the user behaviors and the corresponding temporal information, DTIAN captures user interests and intent changes to the target item. Therefore, the users’ recent interests are enhanced compared to early interests with the attention mechanism. In addition, each module of the proposed model can be plugged into other mainstream models to improve the performance of current models. The experimental results show that the proposed DTIAN can outperform the current popular CTR prediction models slightly and significantly reduce the training time, which makes it possible to implement lightweight models.
Elliptic modular graphs, eigenvalue equations and algebraic identities
Authors: Basu Anirban
Published: June 2023

We obtain eigenvalue equations satisfied by various elliptic modular graphs with five links where two of the vertices are unintegrated. Solving them leads to several nontrivial algebraic identities between these graphs.
Bifurcation of streamlines in channel and tube flow of FENE-P fluid due to peristaltic activity
Authors: Ali N. , Rasool H. , Ullah K.
Published: June 2023

In this paper, we have analyzed the bifurcation of stagnation points in the non-Newtonian flow of the FENE-P fluid through a channel induced by peristalsis. The stream function for the flow under consideration is developed under negligible inertia and streamline curvature effects. A nonlinear autonomous system is developed for scrutiny of the critical points. A dynamical system approach is used to examine the stability of bifurcation points. Streamline patterns, and local and global bifurcation diagrams are plotted for analysis of the backward flow, trapping, and augmented flow regions. The impacts of important embedded parameters, i.e., extensibility parameter and Deborah number on local and global bifurcation diagrams, are also examined. The whole analysis reveals that two critical conditions appear in the flow field that are actually responsible for the conversion of backward flow to trapping and trapping to augmented flow. It is further seen that bifurcations occur at lower flow rates for increasing Deborah’s number while an opposite trend prevails for increasing the extensibility parameter. A comparison of bifurcations between planar and axisymmetric flows is also performed. It is observed that a greater area of the trapping region is encountered for axisymmetric flow than that for planar flow.
Modeling for ammonia gas concentration detection of GaN-based sensors
Authors: Qiang Lei
Published: June 2023

Excellent properties of gallium nitride (GaN) make it an ideal material for realizing gas sensors, especially for ammonia (NH[Formula: see text] detection. Although many researchers have pursued to describe the characteristics of GaN-based NH3 gas sensors by different approaches, few models have been reported. In this paper, with the consideration of the exponential distribution of interfacial states, a model for ammonia concentration detection of GaN gas sensors has been presented. The Poisson equation is applied to model the effect of defect states on the potential. By taking advantage of the current-voltage characteristics, the value of Schottky barrier height can be obtained. The concentration of the adsorbed NH3 gas is derived by exploiting the surface potential. It indicates that densities of acceptor interfacial trap states are in the order of 10[Formula: see text][Formula: see text]cm[Formula: see text]eV[Formula: see text]. The current increases with the NH3 concentration at the same applied voltage. In addition, detailed investigations of physical mechanisms and the analysis of the sensitivity have been depicted. It shows that the sensitivity followed an approximately exponential dependence on NH3 density. Results compared well with experimental data that verify the proposed model and simulation method.
Cross-Modal Interaction Network for Video Moment Retrieval
Authors: Ping Shen , Jiang Xiao , Tian Zean , Cao Ronghui , Chi Weiming , Yang Shenghong
Published: June 2023

The video moment retrieval task aims to fetch a target moment in an untrimmed video, which best matches the semantics of a sentence query. Existing methods mainly focus on utilizing two separate modules: one learns intra-modal relations to understand video and query contents, and the other explores inter-modal interactions to build a semantic bridge between video and language. However, intra-modal relations information can be easily overlooked when capturing inter-modal interactions. In fact, intra-modal relations and inter-modal interactions can be learned simultaneously within a unified module to make video and sentence guide each other. Towards this end, we propose a Cross-Modal Interaction Network (CMIN) for video moment retrieval by jointly exploring the intra-modal relations and inter-modal interactions between video frames and query words. In CMIN, a query-guided channel attention module is designed to suppress query-irrelevant visual features and enhance crucial contents; then a cross-attention module simultaneously considers intra-modal relations within each modality and fine-grained inter-modal interactions between frames and words, to enhance the semantic relevance between video and sentence query. Compared to the state-of-the-art methods, the experiments on two public datasets (Charades-STA and TACoS) demonstrate the superiority of our method.
DOMOPT: A Detection-Based Online Multi-Object Pedestrian Tracking Network for Videos
Authors: Huan Ruohong , Zheng Shuaishuai , Xie Chaojie , Chen Peng , Liang Ronghua
Published: June 2023

Due to the problem of low tracking accuracy and weak tracking stability of current multi-object pedestrian tracking algorithms in complex scenes for videos, a Detection-based Online Multi-Object Pedestrian Tracking (DOMOPT) network is proposed. First, a Multi-Level Feature Fusion (MLFF) pedestrian detection network is proposed based on the Center and Scale Prediction (CSP) algorithm. The pyramid convolutional neural network is used as the backbone to enhance the feature extraction capability for small objects. The shallow features and deep features at multiple levels are integrated to fully obtain the position and semantic information to further improve the detection performance for small objects. Then, on the basis of Joint Detection and Embedding (JDE) architecture, a Multi-Branch Pedestrian Appearance (MBPA) feature extraction network is proposed and added into the pedestrian detection network to extract the appearance feature vector corresponding to each pedestrian. The pedestrian appearance feature extraction is treated as a classification task jointly training with the pedestrian detection task, using the multi-task learning strategy. Experimental results show that the proposed network has better tracking accuracy and stability compared with state-of-the-art algorithms.
Intelligent and Accurate Tobacco Curing via Image Recognition and Data Analysis
Authors: Hu Binbin , Meng Ziyang , Chen Yi , Jiang Yonglei , Chang Chunwei , Ke Zengxiang , Chen Jun , Li Hao
Published: June 2023

Existing tobacco curing process assumes a uniform distribution of temperature and humidity in a barn without considering surface, texture, and biochemical properties of leaves, leading to low quality or even inferior end products. This paper proposes a novel curing process by combining image recognition and data analysis techniques that aims to intelligently improve curing quality of tobacco leaves. Specifically, an image recognition technique is first proposed to classify tobacco leaves and determine their placement in a curing barn. Then, data analysis of the biochemical spectrum of the tobacco leaves are conducted to correlate the temperature and humidity with biochemical data features. Extensive experimental results show that proposed curing process achieves 98.68% accuracy in image recognition for tobacco position control and provides an accurate mapping between tobacco state and biochemical spectrum signals.
Conforming and nonconforming virtual element methods for fourth order nonlocal reaction diffusion equation
Authors: Adak Dibyendu , Anaya Verónica , Bendahmane Mostafa , Mora David
Published: June 2023

In this work, we have designed conforming and nonconforming virtual element methods (VEM) to approximate non-stationary nonlocal biharmonic equation on general shaped domain. By employing Faedo–Galerkin technique, we have proved the existence and uniqueness of the continuous weak formulation. Upon applying Brouwer’s fixed point theorem, the well-posedness of the fully discrete scheme is derived. Further, following [J. Huang and Y. Yu, A medius error analysis for nonconforming virtual element methods for Poisson and biharmonic equations, J. Comput. Appl. Math. 386 (2021) 113229], we have introduced Enrichment operator and derived a priori error estimates for fully discrete schemes on polygonal domains, not necessarily convex. The proposed error estimates are justified with some benchmark examples.
Black holes that are too cold to respect cosmic censorship
Authors: Hod Shahar
Published: June 2023

In this essay, it is proved that there are black holes that are dangerously cold. In particular, by analyzing the emission spectra of highly charged black holes we reveal the fact that near-extremal black holes whose Bekenstein–Hawking temperatures lie in the regime [Formula: see text] may turn into horizonless naked singularities, thus violating the cosmic censorship principle, if they emit a photon with the characteristic thermal energy [Formula: see text] (here [Formula: see text] are, respectively, the proper mass and the electric charge of the electron, the lightest charged particle). We therefore raise here the conjecture that, in the yet unknown quantum theory of gravity, the temperatures of well-behaved black-hole spacetimes are fundamentally bounded from below by the relation [Formula: see text].
What are neutron stars made of? Gravitational waves may reveal the answer
Authors: Lu Neil , Scott Susan M. , Wette Karl
Published: June 2023

Neutron stars are one of the most mysterious wonders in the universe. Their extreme densities hint at new and exotic physics at work within. Gravitational waves could be the key to unlocking their secrets. In particular, a first detection of gravitational waves from rapidly-spinning, deformed neutron stars could yield new insights into the physics of matter at extreme densities and under strong gravity. Once a first detection is made, a critical challenge will be to robustly extract physically interesting information from the detected signals. In this essay, we describe initial research towards answering this challenge, and thereby unleashing the full power of gravitational waves as an engine for the discovery of new physics.
BMS symmetry in gravity: Front form versus instant form
Authors: Ananth Sudarshan , Majumdar Sucheta
Published: June 2023

In general relativity, the allowed set of diffeomorphisms or gauge transformations at asymptotic infinity forms the BMS group, an infinite-dimensional extension of the Poincaré group. We focus on the structure of the BMS group in two distinct forms of Hamiltonian dynamics — the instant and front forms. Both similarities and differences in these two forms are examined while emphasizing the role of noncovariant approaches to symmetries in gravity.
STRATEGY FOR SURGICAL CORRECTION OF THORACOLUMBAR KYPHOSIS CAUSED BY ANKYLOSING SPONDYLITIS
Authors: Chen Hao-Wen Howard , Chen Ing-Ho
Published: June 2023

Various osteotomy techniques have been proposed to correct the kyphotic deformities caused by ankylosing spondylitis (AS). However, no technique could cater to all AS-related deformities well regarding the various mobility of calcified discs and the severity of deformities. Therefore, a thorough understanding of the strength and weaknesses of each method is essential. Then, a strategic approach could be formulated to select the most appropriate technique for a specific patient so as to have a correction operation with effectiveness, safety, and surgical simplicity. Among all preoperative examinations, the evaluation of disc mobility and the severity of kyphotic deformity is mandatory, which constitutes the base for the selection of osteotomy techniques. Since posterior column osteotomy (PCO) is the simplest technique, it should be used as much as possible. If up to three mobile discs are preserved, and the severity of the deformity is only moderate, e.g. the global thoracolumbar angle is less than [Formula: see text], contemporary poly-segmental PCO is selected. Staged PCO (SPCO), proposed by the authors, is the enhanced PCO with more excellent correction capability. If the disc mobility is not favorable enough, SPCO can be considered instead. PSO is the most versatile technique, capable of correcting all kinds of deformities regardless of disc mobility and severity of the kyphosis. This technique can be used in every case if surgical complexity is not a concern to the operator. Especially, PSO is the exclusive indication for those firmly ankylosed deformities without any mobile disc.
Unboundedness phenomenon in a model of urban crime
Authors: Fuest Mario , Heihoff Frederic
Published: June 2023

We show that spatial patterns (“hotspots”) may form in the crime model [Formula: see text] which we consider in [Formula: see text], [Formula: see text], [Formula: see text] with [Formula: see text], [Formula: see text] and initial data [Formula: see text], [Formula: see text] with sufficiently large initial mass [Formula: see text]. More precisely, for each [Formula: see text] and fixed [Formula: see text], [Formula: see text] and (large) [Formula: see text], we construct initial data [Formula: see text] exhibiting the following unboundedness phenomenon: Given any [Formula: see text], we can find [Formula: see text] such that the first component of the associated maximal solution becomes larger than [Formula: see text] at some point in [Formula: see text] before the time [Formula: see text]. Since the [Formula: see text] norm of [Formula: see text] is decreasing, this implies that some heterogeneous structure must form.

We do this by first constructing classical solutions to the nonlocal scalar problem [Formula: see text] from the solutions to the crime model by taking the limit [Formula: see text] under the assumption that the unboundedness phenomenon explicitly does not occur on some interval [Formula: see text]. We then construct initial data for this scalar problem leading to blow-up before time [Formula: see text]. As solutions to the scalar problem are unique, this proves our central result by contradiction.
Thermal Vibration Analysis of Sandwich Cylindrical Shells with Porous FGM Surface Layers
Authors: Liang Chen , Chen Zhenyu , Wang Guifeng , Lim C. W.
Published: June 2023

This study aims at investigating the thermal vibration characteristics of sandwich cylindrical shells consisting of two surface layers crafted from functionally graded materials (FGMs) and a central metal core layer. The sandwich cylindrical shells with FGMs surface layers, with and without porosity, are modelled by using the Kirchhoff–Love shell theory. A porosity function composed of three distinct parts is introduced, including the core-to-thickness ratio, porosity volume fraction, and porosity distribution function. Through the function, the significant effects of porosity that varies with the mixing degree of constituent materials can be analyzed. The material properties are assumed to be temperature-dependent and they show continuous graded variation along the thickness direction. A theoretical approach for analyzing thermal strain energy in the cylindrical shells subjected to thermal environments is established by incorporating Green’s nonlinear strains. The governing equations are derived by applying Hamilton’s principle. Subsequently, analytical solutions for the system’s natural frequencies are determined. Further, to validate the analytical results, a comparative analysis is conducted, drawing upon numerical simulations and other data available in the open literature. Additionally, the thermal vibration characteristics of the composite shell structures are examined in a comprehensive study with respect to various parameters such as porosity type, porosity volume fraction, core-to-thickness ratio, power-law exponent, and temperature changes.
Seismic Performance Analysis of the Two-Dimensional Isolation Device for Double-Layer Grid Structure
Authors: Zhang Tian , Xu Zhao-Dong , Huang Xing-Huai , Dong Yao-Rong , Shi Qing-Xuan
Published: June 2023

The isolation technologies are adopted to protect the long-span space structures from serious damage under the action of earthquakes. When the isolation system is applied to the space structures, both horizontal and vertical vibration control effects on the structures should be concerned. In this paper, a two-dimensional earthquake isolation and mitigation device (TEIMD) composed of a high-damping viscoelastic (VE) core pad and VE dampers is proposed. Based on the dynamic shear experiment results of the VE damper, the energy dissipation capability of VE material is preferable. Then, the nonlinear equivalent stiffness and equivalent damping ratio of the TEIMD in horizontal and vertical directions are evaluated by using the numerical simulation method. The TEIMDs are arranged on the column top of a double-layer grid structure to assess the isolation effectiveness of the novel device. The dynamic analysis results of the double-layer grid structure with and without TEIMD reveal that this novel device can significantly reduce the acceleration response of the upper grid by relying on the strong energy dissipation performances in the horizontal and vertical directions. This research also verifies the feasibility of applying the TEIMD to the double-layer grid structure, which can effectively dissipate the vertical vibration energy of the structure.
Dynamic Analysis of Coupled Train and Cracked Bridge Systems Using Multiscale Finite Element Modeling
Authors: Li Huile , Wang Tianyu , Yan Huan
Published: June 2023

Cracking frequently encountered in railway bridges can lead to significant changes in bridge dynamic characteristics and further dynamic performance of train–bridge interaction (TBI) system. It is desirable to develop an effective method to understand the dynamic behavior of coupled train and cracked bridge systems. This paper proposes a framework for coupled vibration analysis of train and cracked bridge systems using multiscale finite element modeling. A multiscale bridge model adopting frictional surface–surface contact to characterize nonlinear breathing phenomenon of the crack is incorporated into the three-dimensional coupled TBI model. Subsequently, a multiloop numerical solution strategy is formulated to solve the established dynamic equation of coupled train and cracked bridge systems. The proposed framework is used to analyze the cracked beams presented in the literature, and the obtained and literature data are compared. Moreover, an actual heavy-haul railway bridge is taken as an illustrative example, in which vehicle dynamic response, bridge vibration, and train running safety index are calculated considering various crack types, train speeds, and track conditions. The results show that apart from the bridge displacement and acceleration, the presence of crack can have a large influence on the vehicle acceleration response, derailment factor, and offload factor. Differences larger than ±10% in the maximum dynamic indices associated with the intact and cracked bridges are observed, indicating the necessity of considering the crack damage in train–bridge coupled dynamic analysis.
Dynamic Response of Continuous Uphill Pavement with Multi-Layer Plate on Viscoelastic Half-Space Foundation
Authors: Li Shaoqi , Yan Zhanyou , Cui Yongchang , Hou Xueke , Qiao Bo
Published: June 2023

In order to study the dynamic response of driving vehicles on mountainous roads, a three-dimensional (3D) pavement roughness model is reconstructed using the random sine wave superposition method and MATLAB combined with Trucksim software. The road structure is simulated using an infinite multi-layer plate model on a viscoelastic half-space foundation. Through the continuous uphill operation of a three-axle vehicle, the 3D forces of vehicle–road interaction and vehicle driving process are analyzed, and use a self-developed generalized integral calculation program to solve the vertical displacement of a four-layer plate. The results show that compared to 2D pavement, the maximum and root mean square values of longitudinal and lateral forces on 3D pavement differ significantly, with 3D pavement having a 42.95% higher lateral force than 2D pavement. When the vehicle is driving on a circular gentle ramp, the 3D force of the vehicle–road interaction changes significantly. Compared with longitudinal and lateral forces, the vertical force is more significant and more sensitive to the road shape. The vertical displacement impact of multiple tires on the road is not simply the sum of the actions of each tire, comprehensive consideration is needed based on tire position. For example, the influence of track width and other factors. The research results can provide technical guidance for heavy vehicles to continuously climb slopes, pass through arch bridges, culverts, and other working conditions.