bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of ancestral mammalian alkaline phosphatase bearing high stability and productivity
Authors: Hagiwara Yusuke , Mihara Yasuhiro , Motoyama Tomoharu , Ito Sohei , Nakano Shogo
Published: November 2024

Mammalian alkaline phosphatase (AP) is widely used in diagnostics and molecular biology but its widespread use is impaired because it is difficult to express in
Escherichia coli
and has low thermostability. To overcome these challenges, we employed sequence-based protein redesign methods, specifically full consensus design (FCD) and ancestral sequence reconstruction (ASR), to create APs with enhanced properties. Biochemical analyses revealed that these newly designed APs exhibited improved levels of expression in their active form and increased thermostability compared to bovine intestinal AP isozyme II (bIAPII), without impeding enzymatic activity. Notably, the activity in culture broth of the designed APs was an order of magnitude higher than that of bIAPII, and their thermal stability increased by 13°C–17°C (measured as
T
50
). We also assessed 28 single-point mutants of bIAPII to identify regions influencing thermostability and expression level; these mutations were common in the engineered APs but not in bIAPII. Specific mutations, such as T413E and G402S, enhanced thermostability, whereas increasing the expression level required multiple mutations. This suggests that a synergistic effect is required to enhance the expression level. Mutations enhancing thermostability were located in the crown domain, while those improving expression were close to the dimer interface, indicating distinct mechanisms underpinning these enhancements.

IMPORTANCE

Sequence-based protein redesign methods, such as full consensus design (FCD) and ancestral sequence reconstruction (ASR), have the potential to construct new enzymes utilizing protein sequence data registered in a rapidly expanding sequence database. The high thermostability of these enzymes would expand their application in diagnostics and molecular biology. These enzymes have also demonstrated a high level of active expression by
Escherichia coli
. These characteristics make these APs attractive candidates for industrial application. In addition, different amino acid residues are primarily responsible for thermal stability and active expression, suggesting important implications for strategies for designing enzymes by FCD and ASR.
Laboratory detection of carbapenemases among Gram-negative organisms
Authors: Simner Patricia J. , Pitout Johann D. D. , Dingle Tanis C.
Published: November 2024

The carbapenems remain some of the most effective options available for treating patients with serious infections due to Gram-negative bacteria. Carbapenemases are enzymes that hydrolyze carbapenems and are the primary method driving carbapenem resistance globally. Detection of carbapenemases is required for patient management, the rapid implementation of infection prevention and control (IP&C) protocols, and for epidemiologic purposes. Therefore, clinical and public health microbiology laboratories must be able to detect and report carbapenemases among predominant Gram-negative organisms from both cultured isolates and direct from clinical specimens for treatment and surveillance purposes. There is not a “one size fits all” laboratory approach for the detection of bacteria with carbapenemases, and institutions need to determine what fits best with the goals of their antimicrobial stewardship and IP&C programs. Luckily, there are several options and approaches available for clinical laboratories to choose methods that best suits their individual needs. A laboratory approach to detect carbapenemases among bacterial isolates consists of two steps, namely a screening process (
e.g.
, not susceptible to ertapenem, meropenem, and/or imipenem), followed by a confirmation test (
i.e.
, phenotypic, genotypic or proteomic methods) for the presence of a carbapenemase. Direct from specimen testing for the most common carbapenemases generally involves detection
via
rapid, molecular approaches. The aim of this article is to provide brief overviews on Gram-negative bacteria carbapenem-resistant definitions, types of carbapenemases, global epidemiology, and then describe in detail the laboratory methods for the detection of carbapenemases among Gram-negative bacteria. We will specifically focus on the
Enterobacterales, Pseudomonas aeruginosa
, and
Acinetobacter baumannii
complex.
Enriching the future of public health microbiology with hybridization bait capture
Authors: Beaudry Megan S. , Bhuiyan Mohammad Imtiaj Uddin , Glenn Travis C.
Published: November 2024

Public health microbiology focuses on microorganisms and infectious agents that impact human health. For years, this field has relied on culture or molecular methods to investigate complex samples of public health importance. However, with the increase in accuracy and decrease in sequencing cost over the last decade, there has been a transition to the use of next-generation sequencing in public health microbiology. Nevertheless, many available sequencing methods (e.g., shotgun metagenomics and amplicon sequencing) do not work well in complex sample types, require deep sequencing, or have inherent biases associated with them. Hybridization bait capture, also known as target enrichment, brings in solutions for such limitations. It is an increasingly popular technique to simultaneously characterize many thousands of genetic elements while reducing the amount of sequencing needed (thereby reducing the sequencing costs). Here, we summarize the concept of hybridization bait capture for public health, reviewing a total of 35 bait sets designed in six key topic areas for public health microbiology [i.e., antimicrobial resistance (AMR), bacteria, fungi, parasites, vectors, and viruses], and compare hybridization bait capture to previously relied upon methods. Furthermore, we provide an in-depth comparison of the three most popular bait sets designed for AMR by evaluating each of them against three major AMR databases: Comprehensive Antibiotic Resistance Database, Microbial Ecology Group Antimicrobial Resistance Database, and Pathogenicity Island Database. Thus, this article provides a review of hybridization bait capture for public health microbiologists.
Animal models for exploring Chagas disease pathogenesis and supporting drug discovery
Authors: Khan Archie A. , Taylor Martin C. , Fortes Francisco Amanda , Jayawardhana Shiromani , Atherton Richard L. , Olmo Francisco , Lewis Michael D. , Kelly John M.
Published: November 2024

SUMMARY

Infections with the parasitic protozoan
Trypanosoma cruzi
cause Chagas disease, which results in serious cardiac and/or digestive pathology in 30%–40% of individuals. However, symptomatic disease can take decades to become apparent, and there is a broad spectrum of possible outcomes. The complex and long-term nature of this infection places a major constraint on the scope for experimental studies in humans. Accordingly, predictive animal models have been a mainstay of Chagas disease research. The resulting data have made major contributions to our understanding of parasite biology, immune responses, and disease pathogenesis and have provided a platform that informs and facilitates the global drug discovery effort. Here, we provide an overview of available animal models and illustrate how they have had a key impact across the field.
Performance evaluation of the Specific Reveal system for rapid antibiotic susceptibility testing from positive blood cultures containing Gram-negative pathogens
Authors: Ostermann Greta , Körber-Irrgang Barbara , Krüger Alexander , Singh Pragya , Vo Kenny , Gielen Jörg , Aurbach Ute , Wisplinghoff Hilmar , Jazmati Nathalie
Published: November 2024

Rapid antimicrobial drug administration is crucial for the efficient treatment of sepsis or septic shock, but empirical therapy is limited by the increasing prevalence of multidrug-resistant bacteria. Thus, rapid and reliable antimicrobial susceptibility testing (AST) is needed to start appropriate antimicrobial drug administration as quickly as possible. In the present study, we evaluated the performance of the Reveal rapid AST system. From February to April 2021, 102 positive blood culture bottles (BCBs) from hospitalized patients with bacteremia caused by Gram-negative bacteria were included in the study. All isolates were tested by the Reveal system directly from the positive BCBs in comparison to the DxM MicroScan WalkAway. Essential agreement (EA) and category agreement (CA) were high with 98.5% and 97.1%, respectively. We also determined the susceptibility of 10 highly resistant CDC & FDA AR strains in duplicate. Here, EA was 99.6% and CA 97.9%. The average time to result by Reveal was 5.4 h ± 1.2 h compared to an average of 16 h by DxM MicroScan WalkAway for clinical strains and 3.8 h ± 1.2 h for more resistant CDC & FDA AR strains. Susceptibility determination with the Reveal rapid AST system directly from positive BCBs is for the frequently represented bug-drug combinations a reliable and accurate approach, meeting the European ISO guideline for the performance of AST systems. Moreover, AST directly from blood cultures performed with the Reveal system saves time when compared to the conventional AST, as no subculturing is needed and time to result is very short.
Exosome-mediated viral nucleic acid presentation in a crustacean expounds innate immunity from a novel perspective
Authors: Gong Yi , Hu Hang , Zhao Xinshan , Wei Weiqian , Zhang Ming , Tran Ngoc Tuan , Ma Hongyu , Zhang Yueling , Chan Kok-Gan , Li Shengkang
Published: November 2024

As an enduring hot topic in the field of innate immunity, apoptosis is widely considered an effective approach to eliminate pathogenic microbes and plays a crucial role during host–pathogen interactions. Recently, researchers have found that the virus-containing host cells could transmit apoptotic signals to the surrounding uninfected cells during infection, but the mechanism remains unclear. Here, we found that exosomes secreted by WSSV-infected mud crab hemocytes contain viral nucleic acid wsv277, which could be transported to the recipient cells and further expressed viral protein with phosphokinase activity. Besides, by using transcriptome, proteome, ChIP-seq, and coIP techniques, the results revealed that wsv277 could activate the transcription and translation of apoptotic genes via interacting with CBF and EF-1α so as to suppress the spread of virus infection by inducing apoptosis of the surrounding cells. Therefore, for the first time, our study proved that the components of DNA virus could be encapsulated into exosomes and elucidated the mechanism of apoptotic signal transduction between cells from the perspective of exosomes.

IMPORTANCE

Our study revealed that the components of DNA virus could be packaged and transmitted through the exosomes of lower invertebrates, which strongly demonstrated the diversity of exosome-mediated viral immunity and its universality in animals. Furthermore, we elucidated the mechanism of apoptotic signal transduction between cells from the perspective of exosomes and revealed a novel strategy for the host to cope with viral infection.
Effect of an oral stimulation protocol on breastfeeding among preterm infants: a randomised controlled trial
Authors: Jayapradha Gopalakrishnan , Venkatesh Lakshmi , Amboiram Prakash , Balasubramanium Radish Kumar , Balakrishnan Umamaheswari
Published: November 2024

Objectives

The objectives are to assess the effectiveness of a modified and adapted oral sensorimotor intervention (MA-OSMI) protocol for infants in India on the rate and performance of breastfeeding among preterm (PT) infants at discharge.

Design

Single-centre randomised control trial.

Setting

Level III B neonatal intensive care unit in a quaternary care hospital in South India.

Patients

A total of 76 PT infants born between 26 and 33+6weeks of gestational age, stratified into <30 weeks and 30–33+6weeks, were randomised to intervention group (MA-OSMI) or standard care (SC).

Interventions

MA-OSMI in addition to SC versus SC alone. The stimulation included 12 techniques administered by the principal investigator. SC included kangaroo mother care and non-nutritive sucking.

Outcome measures

Exclusive breastfeeding (EBF) rate and breastfeeding performance at the time of discharge, assessed using standardised tools by clinician and mothers.

Results

Infants in MA-OSMI group (66%) had significantly higher EBF rate compared with the SC group (16%) (OR: 10.25; 95% CI: 3.41 to 30.80). Improved breastfeeding performance was noted as per the clinician’s observation. Significantly lower scores for MA-OSMI groups (63.42±36.43) than SC groups (126.61±60.94) on mothers’ ratings suggested better feeding skills.

Conclusion

Prefeeding oral stimulation contributed significantly to the achievement of EBF among PT infants at discharge. The present findings may benefit speech–language pathologists, paediatricians/neonatologists and nurses in the intervention of oral feeding among neonates.
Lefamulin forMycoplasma genitaliumtreatment failure in Australia and the USA: a case series and pilot open-label parallel arm randomised trial
Authors: Ramchandani Meena S , Plummer Erica L , Parker Anika , Vodstrcil Lenka A , Soge Olusegun O , Aguirre Ivette , Kim Joong , Hughes James P , Barbee Lindley A , Jensen Jørgen Skov , Manhart Lisa E , Bradshaw Catriona S
Published: November 2024

Objectives

Mycoplasma genitalium(MG) causes urethritis and is associated with cervicitis, pelvic inflammatory disease and preterm delivery. Antimicrobial resistance is widespread and cure rates are declining. Lefamulin, a novel pleuromutilin, may be effective in cases of treatment failure.

Methods

Under compassionate access in Australia and a pilot open-label parallel arm randomised clinical trial in the USA, patients with urogenital MG infection and microbiological treatment failure or contraindications to moxifloxacin were treated with lefamulin monotherapy (600 mg orally two times per for 7 days) or sequential doxycycline-lefamulin (doxycycline 100 mg orally two times per day for 7 days followed by lefamulin for 7 days) (1:1 randomisation in the USA). Two additional regimens were also evaluated in Australia: combination therapy with doxycycline plus lefamulin for 7 days and extended lefamulin therapy with doxycycline for 7 days followed by lefamulin for 14 days. Microbiological cure (negative MG NAAT) was assessed 21–35 days after completing lefamulin. Sustained cure was assessed 42–49 days after treatment.

Results

Seventeen heavily pretreated Australian (seen between October 2020 and December 2023) and 11 US cases (recruited between April 2022 and February 2023; 5 randomised to lefamulin monotherapy, 6 randomised to sequential doxycycline-lefamulin) received lefamulin-containing regimens. Sequential doxycycline-lefamulin demonstrated microbiological cure 21–35 days post-treatment in 6 of 12 (50%) Australian and US patients. Three of five (60%) US patients but none of five (0%) Australian patients were cured with lefamulin monotherapy. Combination therapy with doxycycline and lefamulin was ineffective (n=0/2), but extended lefamulin therapy cured two of three (67%). Gastrointestinal side effects occurred in 77% (Australia) and 91% (USA).

Conclusion

While cure rates were low, lefamulin was effective in some individuals with MG treatment failure. Additional antibacterial agents for multidrug-resistant infections are needed.
Direct Detection Searches for Dark Matter Particles using Superheated Bubble Chambers and Cryogenic Liquid Argon Detectors
Authors: Krauss Carsten , Viel Simon
Published: November 2024

This review spotlights Canadian participation to experiments aimed at the direct detection of dark matter particles, with sensitivity over a mass range from the GeV scale to the Planck scale. Two technologies are discussed: superheated bubble chambers (PICASSO, COUPP, PICO, SBC) and cryogenic liquid argon detectors (DEAP, DarkSide, ARGO). We present the recent history, current status, and future plans of these research endeavours.
Regularized-renormalized-resummed loop corrected power spectrum of non-singular bounce with Primordial Black Hole formation
Authors: Choudhury Sayantan , Karde Ahaskar , Panda Sudhakar , SenGupta Soumitra
Published: November 2024

We present a complete and consistent exposition of the regularization, renormalization, and resummation procedures in the setup of having a contraction and then non-singular bounce followed by inflation with a sharp transition from slow-roll (SR) to ultra-slow roll (USR) phase for generating primordial black holes (PBHs). We consider following an effective field theory (EFT) approach and study the quantum loop corrections to the power spectrum from each phase. We demonstrate the complete removal of quadratic UV divergences after renormalization and softened logarithmic IR divergences after resummation and illustrate the scheme-independent nature of our renormalization approach. We further show that the addition of a contracting and bouncing phase allows us to successfully generate PBHs of solar-mass order, $$M_\textrm{PBH}\sim \mathcal{O}(M_{\odot })$$

M
PBH

∼
O

(

M
⊙

)

, by achieving the minimum e-folds during inflation to be $$\Delta N_{\textrm{Total}}\sim \mathcal{O}(60)$$

Δ

N
Total

∼
O

(
60
)

and in this process successfully evading the strict no-go theorem. We notice that varying the effective sound speed between $$0.88\leqslant c_{s}\leqslant 1$$

0.88
⩽

c
s

⩽
1

, allows the peak spectrum amplitude to lie within $$10^{-3}\leqslant A \leqslant 10^{-2}$$

10

-
3

⩽
A
⩽

10

-
2

, indicating that causality and unitarity remain protected in the theory. We analyse PBHs in the extremely small, $$M_{\textrm{PBH}}\sim \mathcal{O}(10^{-33}-10^{-27})M_{\odot }$$

M
PBH

∼
O

(

10

-
33

-

10

-
27

)

M
⊙

, and the large, $$M_{\textrm{PBH}}\sim \mathcal{O}(10^{-6}-10^{-1})M_{\odot }$$

M
PBH

∼
O

(

10

-
6

-

10

-
1

)

M
⊙

, mass limits and confront the PBH abundance results with the latest microlensing constraints. We also study the cosmological beta functions across all phases and find their interpretation consistent in the context of bouncing and inflationary scenarios while satisfying the pivot scale normalization requirement. Further, we estimate the spectral distortion effects and shed light on controlling PBH overproduction.
Anisotropic gravastar as horizonless regular black hole spacetime and its images illuminated by thin accretion disk
Authors: Fauzi M. F. , Ramadhan H. S. , Sulaksono A.
Published: November 2024

A connection between regular black holes and horizonless ultracompact objects was proposed in Carballo-Rubio et al. (JHEP 08:046, 2023, arXiv:2211.05817 [gr-qc]). In this paper, we construct a model of a horizonless compact object, specifically an anisotropic gravastar with continuous pressure, that corresponds to regular black hole spacetime in the appropriate limit. The construction begins by modeling an equation of state that satisfies the anisotropic gravastar conditions and transitions to the de Sitter ($$p=-\epsilon $$

p
=
-
ϵ

) upon horizon formation. The spacetime structure is similar to the Quantum Horizonless Compact Object (QHCO) described in Chen and Yokokura (Phys Rev D 109:104058, 2024, arXiv:2403.09388 [gr-qc]). Within this model, we also generate images of the corresponding objects surrounded by a thin accretion disk. The resulting images reveal that assuming that the emitting matter exists only outside the object, the inner light ring structure closely resembles that of the horizonless configuration of a regular black hole and the QHCO, yet it exhibits a distinct light ring structure compared to the thin-shell gravastar model. However, the opposite occurs when emitting matter is taken into account inside the object.
New classes of charged 4D EGB spacetimes with vanishing Weyl curvature
Authors: Hansraj Sudan , Mngadi Siyamthanda Remember , Errehymy Abdelghani
Published: November 2024

The configuration of a perfect fluid distribution in an electric field under the influence of higher curvature geometric effects introduced through the Gauss–Bonnet invariants is studied in the 4 dimensional Glavan–Lin gravity formulation. It is found that whereas a constant spatially directed gravitational potential gives isothermal behaviour in the standard theory, this is not the case when extra curvature is present in general. A physically viable stellar model is constructed by assuming the Finch–Skea potential. The geometry and electrodynamics are well behaved being regular throughout the distribution including the centre. The model passes stability tests such as the Chandrasekar adiabatic stability criterion and causality. Additionally all energy conditions are satisfied within the star. We compare the performance of the model with its Einstein counterpart and observe that the higher curvature exerts a notable influence on all the physical properties of the star.
Brane stability under $$f(Q,{\mathcal {T}})$$ gravity
Authors: Moreira A. R. P. , Dong Shi-Hai
Published: November 2024

The focus of this paper is to investigate the behavior of a codimension-one thick brane in the modified symmetric teleparallel gravity structure $$f(Q, {\mathcal {T}})$$

f
(
Q
,
T
)

, where Q is the nonmetricity scalar and $${\mathcal {T}}$$
T
is the trace of the energy–momentum tensor. Additionally, we examine whether braneworld scenarios are stable under small tensor perturbations and identify the associated massive and resonant modes. Our results indicate that the parameters controlling the modifications to the gravitational model-specifically those affecting nonmetricity and the energy–momentum tensor-significantly influence both the location and existence of these modes.
Multi-Target Detection Method of Intelligent Driving Traffic Scene Based on Faster R-CNN++
Authors: Xu Qiangqiang , Guo Junhua
Published: November 2024

The current multi-objective detection methods are plagued by several issues, including insufficient detection efficiency, slow speeds, and difficulties in deciphering driving rules. To address these challenges, we introduce a traffic scene classification method that utilizes Improved Faster Regions with Convolutional Neural Network features (Faster R-CNN++). Initially, the shared convolutional layer and the Recurrent Criss-Cross Attention (RCCA) layer are employed to extract features from the input image. Subsequently, the derived feature map is fed into the Region Proposal Network (RPN) to generate detection boxes, and the Region of Interest Align (RoI Align) layer selects features corresponding to each Region of Interest (RoI) on the feature map, guided by the RPN’s output. Ultimately, we adopt an alternating training approach. Simulation experiments confirm the effectiveness of our method in multi-scene object detection. Our method has demonstrated significant improvements over existing algorithms and has delivered outstanding performance on the BDD-100[Formula: see text]K, ApolloScape, and NuScenes datasets. The results indicate that our deep learning-based traffic scene classification method can accurately discern the behavioral characteristics of various traffic participants.
A Fusion Attention Mechanism with Bi-LSTM-Based Sarcasm Detection for Selecting High-Profit Products
Authors: Gayathri C. , Ravindran R. Samson
Published: November 2024

Social media has become an invaluable resource for gathering customer feedback in today’s digital era. As technology and the internet evolve, vast quantities of data are generated from numerous sources such as social blogs and websites. Recently, webpages and blogs have emerged as primary channels for obtaining real-time consumer feedback. However, the sheer volume of blogs on the cloud has led to overwhelming information in various forms, including attitudes, opinions, and reviews. For product reviews, it is possible to discern the reviewer’s perspective on specific product characteristics rather than the product as a whole. Nonetheless, sarcastic reviews pose a challenge in accurately determining the sentiment class of the review. This paper proposes a sarcastic review prediction-based sentiment analysis approach to address this issue. The proposed method comprises three stages: pre-processing, feature extraction, and prediction. Initially, reviews are collected and pre-processed using tokenization, stop word removal, and stemming. Following pre-processing, feature extraction is performed, wherein sentimental, punctuation, and TF-IDF features are extracted from each review. These extracted features are then fed into a Bidirectional Long Short-Term Memory (Bi-LSTM) network with an attention mechanism to predict whether a product review is sarcastic or non-sarcastic. The fusion attention mechanism assigns attentive weights to each word, enhancing the prediction accuracy. The performance of the proposed approach is evaluated using various metrics and compared against state-of-the-art techniques. The results demonstrate the effectiveness of the proposed method in accurately predicting sarcastic reviews.
An Efficient Algorithm for the 2-Central Path Problem
Authors: Huang Ziyun , Zhu Yongding , Xu Jinhui
Published: November 2024

In this paper we consider the following [Formula: see text]-Central Path Problem (2CPP): Given a set of [Formula: see text] polygonal curves [Formula: see text] in the plane, find two curves [Formula: see text] and [Formula: see text], called [Formula: see text]-central paths, that best represent all curves in [Formula: see text]. Despite its theoretical interest and a wide range of practical applications, 2CPP has not been well studied. In this paper, we first establish criteria that [Formula: see text] and [Formula: see text] ought to meet in order for them to best represent [Formula: see text]. In particular, we require that there exists parametrizations [Formula: see text] and [Formula: see text] ([Formula: see text]) of [Formula: see text] and [Formula: see text] respectively such that the maximum distance from [Formula: see text] to curves in [Formula: see text] is minimized. Then an efficient algorithm is presented to solve 2CPP under certain realistic assumptions. Our algorithm constructs [Formula: see text] and [Formula: see text] in [Formula: see text] time, where [Formula: see text] is the total complexity of [Formula: see text] (i.e., the total number of vertices and edges), [Formula: see text] is the number of curves in [Formula: see text], and [Formula: see text] is the inverse Ackermann function. Our algorithm uses parametric search technique and is considerably faster than arrangement-related algorithms (i.e. [Formula: see text]) when [Formula: see text] as in most real applications.
Modeling less complex fuzzy dark matter cylindrical wormholes
Authors: Yousaf Z. , Almutairi Bander , Rizwan M. , Ganesan T. , Bhatti M. Z.
Published: November 2024

The objective of this paper is to provide a piece of theoretical evidence for the existence of cylindrically symmetric, time-independent wormhole models surrounded by the halos of fuzzy dark matter. To do so, we model our system by assuming a cylindrical spacetime coupled with locally anisotropic matter content. We calculate the shape function involved in the construction of fuzzy dark matter wormholes, by solving simultaneous equations of motion and density powered by Einasto energy profile. The investigation of the validity of null energy conditions is performed with the aim of seeing stable wormhole structures. The role of the equation of state parameter in the theoretical structure of the shape function and the redshift function is studied which would lead to understanding the signals’ gravitational redshift and the spatial distribution of the fuzzy wormholes. A few characteristics of the wormholes like hydrostatic equilibrium, and active C-energy are also noticed in the less complex wormholes. It is inferred that the stability as well as the size of the fuzzy dark matter wormholes can be fine-tuned by modulating the index parameter involved in the energy source.
The role of the single-particle state in the topology of the potential energy surface of 72Kr
Authors: Qasim Hanan , Abusara H.
Published: November 2024

The relativistic Hartree–Bogoliubov formalism was employed to explore the role of the nucleon single-particle state in defining the potential energy surface of the [Formula: see text]Kr isotope utilizing density-dependent zero and finite range NN interactions. It is discovered that a significant influence on identifying the ground state minima is the density of states near to the Fermi level.
Learning algorithms versus automatability of Frege systems
Authors: Pich Ján , Santhanam Rahul
Published: November 2024

We connect learning algorithms and algorithms automating proof search in propositional proof systems: for every sufficiently strong, well-behaved propositional proof system [Formula: see text], we prove that the following statements are equivalent,

(1) Provable learning. [Formula: see text] proves efficiently that p-size circuits are learnable by subexponential-size circuits over the uniform distribution with membership queries.

(2) Provable automatability. [Formula: see text] proves efficiently that [Formula: see text] is automatable by non-uniform circuits on propositional formulas expressing p-size circuit lower bounds.

Here, [Formula: see text] is sufficiently strong and well-behaved if I.–III. hold: I. [Formula: see text] p-simulates Jeřábek’s system [Formula: see text] (which strengthens the Extended Frege system [Formula: see text] by a surjective weak pigeonhole principle); II. [Formula: see text] satisfies some basic properties of standard proof systems which p-simulate [Formula: see text]; III. [Formula: see text] proves efficiently for some Boolean function [Formula: see text] that [Formula: see text] is hard on average for circuits of subexponential size. For example, if III. holds for [Formula: see text], then Items 1 and 2 are equivalent for [Formula: see text]. We use the following modified notion of automatability in Item 2, the automating circuits output a [Formula: see text]-proof of a given formula (expressing a p-size circuit lower bound for a function [Formula: see text]) in non-uniform p-time in the length of a shortest [Formula: see text]-proof of a closely related but different formula (expressing an average-case subexponential-size circuit lower bound for the same function [Formula: see text]).

If there is a function [Formula: see text] which is hard on average for circuits of size [Formula: see text], for each sufficiently big [Formula: see text], then there is an explicit propositional proof system [Formula: see text] satisfying properties I.-III., i.e. the equivalence of Items 1 and 2 holds for [Formula: see text].
Investigating the Numerical Stability of Dynamic Relaxation Methods with Automatic Load-Increment Schemes to Improve Snap-Back Prediction
Authors: Yang Chao , Zhang Pengfei , Luo Yaozhi
Published: November 2024

Automatic load incrementation schemes tailor-made for the dynamic relaxation (DR) method, including the minimum residual force (MRF) scheme, the minimum residual energy (MRE) scheme, the minimum displacement increment (MDI) scheme, and the minimum kinetic energy (MKE) scheme, are commonly used to capture snapping phenomena in post-buckling structural analysis. Analogous to DR incorporating arc-length constraints, these combined numerical schemes effectively handle snap-through problems, but their capability to address snap-back behavior remains largely unverified. This study aims to investigate the numerical stability of the DR-MRF, DR-MRE, DR-MDI, and DR-MKE methods. Unexpectedly, all these methods are found to be unconditionally unstable and inadequate for snap-back problems. Key findings include (1) the establishment of a general finite-difference equation in canonical form for these four methods, with numerical stability governed by the spectral radius of the recursive amplification matrix; and (2) the discovery of a special property of the tangent stiffness matrix, where a specific minor becomes negative during snap-back, causing the spectral radius to exceed one and leading to instability. These conclusions are supported by numerical verifications on nonlinear springs, trusses, and frames. Simulations consistently demonstrate the reliability of these findings across different structural configurations.
Closely Spaced Mode Identification of Skyscraper Buildings via Variational Mode Decomposition with Multiple-Signal Classification Algorithm and Recursive Hilbert Transform
Authors: Hu Feng , Zhi Lunhai , Hu Zhixiang , Li Qiusheng
Published: November 2024

Addressing the limitations of traditional modal analysis methods, which struggle with closely spaced modal frequencies and noise interference, this paper introduces a novel approach that integrates variational mode decomposition (VMD) with multiple signal classification (MUSIC) and the recursive Hilbert transform (RHT). This integration leverages the adaptability of VMD in signal decomposition and exploits the high-resolution spectral identification capabilities of MUSIC to decompose the closely spaced modes accurately. Additionally, the RHT is applied to analyze the instantaneous properties of the decomposed signals. The proposed method was validated through a numerical study on a 2DOF model, demonstrating its effectiveness and robustness in identifying modal parameters under simulated conditions. Further validation was conducted through field measurements from a 420[Formula: see text]m high skyscraper building during Super Typhoon Nesat, confirming the practical applicability and effectiveness of the approach in actual engineering cases. The findings indicate a substantial improvement in the accuracy of closely spaced modal parameter identification, thus enhancing the reliability of structural health monitoring (SHM) systems in skyscraper buildings.
Damping Enhancement-Based Analytical Optimization and Performance Evaluation of Tuned Viscous Rotating Mass Damper for Seismic Protection
Authors: Zhang Ruoyu , Huang Mingfeng
Published: November 2024

Inerter systems for passive vibration control offer notable advantages such as being lightweight and delivering high performance. However, the full potential for vibration mitigation in inerter-based dampers, particularly those incorporating additional inertia amplification mechanisms, remains underexplored. In this work, the analytical dynamic model for the tuned viscous rotating mass damper (TVRMD) which is equipped with a double-flywheels mechanism is established, and the closed-form optimal expressions based on the damping enhancement principle (DEP) are derived, achieving more significant deformation enhancement of the damping element. These optimal solutions also provide an efficient and straightforward parameter design method. The vibration mitigation and damping efficiency of the TVRMD are compared with the traditional tuned viscous mass damper (TVMD) via performance evaluations for both Single-Degree-of-Freedom (SDOF) and Multi-Degree-of-Freedom (MDOF) structures equipped with TVRMD. To be more specific, increasing the amplification ratio improves frequency-domain displacement responses and enhances energy dissipation, broadening the frequency range of control forces in the TVRMD. For seismic response control of typical MDOF structures, the TVRMD effectively reduces displacement, acceleration, and base shear force simultaneously in a specific target mode compared to the traditional TVMD. However, excessively increasing [Formula: see text] to improve vibration mitigation performance is not a reasonable strategy and the reasonable range for the value of [Formula: see text] could be 2–3 for a given specific mass ratio. Unlike the mass enhancement effect of traditional inerter systems, the increase in TVRMD control force is attributed to the combined benefits of the amplification mechanism and deformation enhancement of viscous damper, enabling dual improvement in both the control frequency domain and control force while maintaining the same mass ratio as the TVMD.
Vibration Isolation Performance Analysis of a Nonlinear Fluid Inerter-Based Hydro-Pneumatic Suspension
Authors: Shen Yujie , Qiu Dongdong , Yang Xiaofeng , Chen Junjie , Guo Yan , Zhang Tianyi
Published: November 2024

To further enhance the ride comfort of vehicles, a new type of fluid inerter-based hydro-pneumatic suspension (FI-HPS) is proposed. First, this paper combines the fluid type inerter with the dual-chamber hydro-pneumatic suspension (DHPS) and fully considers the nonlinear factors. The nonlinear dynamic model of the fluid inerter is derived, and three structural models, namely the traditional DHPS S0, the ideal FI-HPS S1, and the nonlinear FI-HPS S2, are established. Then, the non-dominated sorting genetic algorithm II (NSGA-II) is employed to optimize the key parameters of the S1 and S2 suspensions. With the S0 suspension as a comparison subject, the simulation results show that the S2 suspension can significantly improve the vehicle’s ride comfort performance. In terms of the time-domain analysis, the root-mean-square (RMS) value of the vehicle body acceleration is reduced by 20.5%, the RMS value of the suspension working space is reduced by 12.7%, and the RMS value of the dynamic tire load is reduced by 8.0%. The frequency domain results indicate that the S2 suspension can effectively reduce the suspension offset frequency vibration, with a more significant effect at low frequencies. Upon analysis of impulsive road conditions, the peak-to-peak (PTP) value of the vehicle body acceleration is reduced by 14.2%, and the PTP value of the suspension working space is reduced by 6.3%. It is revealed that the inclusion of the nonlinear parasitic damping force in the fluid inerter can effectively enhance the overall performance of the hydro-pneumatic suspension system.
Dynamic Response Characteristics of Concrete Gravity Dam Induced by Underwater Explosion: Scaled Model Study
Authors: Fan Yong , Zhou Shuai , Yang Guangdong , Feng Zhenyu , Wang Gaohui , Zhou Tao , Tian Bin
Published: November 2024

A scaled model of a concrete gravity dam was designed, and nine tests were conducted to investigate the dynamic response characteristics of the dam subjected to underwater explosions. The pressure time histories in the water, and the velocity and acceleration time histories of the dam during various explosions were recorded. The acceleration signal was processed by the Fast Fourier Transform (FFT) to perform time–frequency conversion. The energy migration law of the acceleration signal along the dam elevation was explored based on the theory of wavelet packets. Furthermore, the effects of charge weight, explosion distance, and explosion depth on the dynamic response of the dam were comprehensively investigated. The results show that the distribution of peak acceleration along the dam elevation closely relates to the explosion distance, but the global response of the dam tends to weaken as the explosion distance increases. Increasing the charge weight causes an enhancement in the dam response. Compared with an explosion suspended in water, the bottom explosion causes a weaker response to the dam. With the increase of the dam elevation, the energy of the acceleration signal gradually shifts from low frequency to high frequency. The bubble curtain has a significant mitigation effect against underwater explosions.
How to Get and Stay “in the Zone”: The Link Between Team Flow and Creative Output in Design Thinking Workshops
Authors: Primus Dirk J. , Sonnenburg Stephan
Published: November 2024

During Design Thinking (DT) processes, team flow is a vital indicator and driving force behind feeling and performing at peak. In a quasi-experimental, segmented time series study, we examined team flow levels over time using high-resolution, real-time measurements during two multi-day DT workshops with flow-inducing exercises (in short: flow inducers). Two key insights emerged: (1) a second wind effect, where teams naturally increased flow after the initial engagement phase; and (2) a preservation capacity, where teams with greater creative outputs maintained higher flow levels despite interruptions (in short: flow reducers). The careful management of flow-inducing exercises and workshop duration should give teams the flexibility needed to dynamically adjust and stay in the zone. These findings inform the development of a framework for sustaining team flow in multi-day workshops, the core contribution of this study. The framework offers practical recommendations to manage team flow in stages, emphasizing key points of intervention and optimal timing of flow inducers. It is adaptable for various co-creative settings, guiding facilitators in maximizing creative persistence and output.
Timelike non-minimal CMC translation surfaces in Minkowski 3-spaces
Authors: Ali Ahmad Tawfik
Published: November 2024

In this paper, we show that there is no timelike translation surface with non-minimal constant mean curvature [Formula: see text], constructed by the sum of a timelike plane curve and a timelike space curve in Minkowski 3-space [Formula: see text].
Dynamics of pre-inflationary universe in loop quantum cosmology
Authors: Shahalam M.
Published: November 2024

In this paper, we examine the pre-inflationary universe for the potential [Formula: see text] in the framework of loop quantum cosmology. We choose such type of potential as the quadratic potential is almost disfavored by the Planck 2018 data. We primarily study the initial conditions of the inflaton field that are physically viable and produce the slow-roll inflation. We also obtain the number of [Formula: see text]-folds in the slow-roll regime that are consistent with the observations. In addition, we present the phase space analysis and show that the slow-roll inflation is an attractor for a wide range of initial conditions.
Presence of exotic matter in Levia–Civita and cosmic string solutions
Authors: Malik Adnan , Mofarreh Fatemah
Published: November 2024

This paper explores the cylindrically symmetric solutions within the framework of modified [Formula: see text] theories of gravity, where [Formula: see text] is the Ricci scalar. This study focuses on analyzing the cylindrical solutions within realistic space-time regions and investigates three distinct cases of exact solutions derived from the field equations of the [Formula: see text] theory of gravity. For our current work, we examine the well-known Levi-Civita and cosmic string solutions in [Formula: see text] modified theory of gravity. Furthermore, we also discuss the energy conditions for considered cases. Notably, a violation of null energy conditions is observed, suggesting the potential existence of cylindrical wormholes. The findings contribute to the understanding of modified [Formula: see text] theories of gravity, providing valuable insights into the nature of cylindrically symmetric solutions and their implications in theoretical physics.
A viable model of self-gravitating object in the 5D Einstein Gauss–Bonnet gravity
Authors: Tahir M. , Shahzad M. R. , Shoaib M. , Algehyne Ebrahem A. , Mahmoud Emad E.
Published: November 2024

In this paper, we investigated new solutions for the anisotropic compact stellar model in Einstein–Gauss–Bonnet (EGB) theory. In this context, we established a set of field equations with the help of anisotropic matter configuration. The relation between pressure in the radial direction and the energy density is taken by using a linear equation of state (EoS). A well-known Boulware–Deser exterior spacetime is matched with interior spherically symmetric spacetime at the boundary of the star to determine the unknown parameters. Different physical parameters are investigated, namely, these are density, radial pressure and transversal pressure, anisotropy, mass function, compactness and surface redshift. We discussed Herrera’s cracking condition, Tolman–Oppenheimer–Volkoff (TOV), and the adiabatic index. The values of some physical quantities like density (at center and surface), compactness and surface redshift are calculated numerically for three compact stars PSR J0348+0432, PSR J0740+6620 and PSR J0030+0451. A graphical analysis of these physical quantities for a representative compact star candidate PSR J0348+0432 is also presented with various values of EGB parameter [Formula: see text]. The energy conditions for anisotropic compact star PSR J0348+0432 are satisfied, surface redshift remains within the limit and also all the stability conditions that we discussed in this work are satisfied, this validates our presented model. The effects of the GB coupling parameter [Formula: see text] on the physical parameters are depicted graphically and numerically.
Noether symmetries of the minimal surface Lagrangian for Gödel-type spacetimes
Authors: Camci Ugur
Published: November 2024

We investigate the Noether symmetries of the minimal surface Lagrangian for four classes of metrics in Gödel-type spacetimes. Then, calculating the Noether symmetries for all classes, namely, classes I, II, III and IV, we determine the conserved fields corresponding to each class, allowing us to derive a comprehensive characterization of the minimal surface equations for Gödel-type spacetimes.
New dynamical behaviors and soliton solutions of the coupled nonlinear Schrödinger equation
Authors: Wang Kang-Le
Published: November 2024

In this work, we mainly investigate the coupled nonlinear Schrödinger type equation,which is employed to elaborate the propagation of waves in different fields like Bose–Einstein condensations (BEC) in plasma physics, ultra-short pulses in birefringent fibers and pressure pulses in artery vessels. The study of multi-component equations has gained significant interest due to their ability to elucidate complex physical phenomena and exhibit dynamic structures of localized wave solutions. Diverse novel soliton solutions of the coupled nonlinear Schrödinger type equation are successfully constructed via the unified solver method and improved F-expansion method. The dynamic behaviors of these obtained solutions are elaborated by sketching some three-dimensional (3D) and two-dimensional (2D) graphs. The two efficient mathematical approaches can be widely employed to solve other types of nonlinear partial differential equations (NLPDEs).
Higher reciprocity laws and ternary linear recurrence sequences
Authors: Moree Pieter , Noubissie Armand
Published: November 2024

In this paper, we describe the set of prime numbers splitting completely in the non-abelian splitting field of certain monic irreducible polynomials of degree [Formula: see text] As an application, we establish some divisibility properties of the associated ternary recurrence sequence by primes [Formula: see text], thus greatly extending recent work of Evink and Helminck [Tribonacci numbers and primes of the form [Formula: see text], Math. Slovaca 69(3) (2019) 521–532] and of Faisant [On the Padovan sequence (2019), https://arxiv.org/abs/1905.07702]. We also prove some new results on the number of solutions of the characteristic equation of the recurrence sequence modulo [Formula: see text].