bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trial of labour after caesarean section in Sub‐Saharan Africa: A systematic review and meta‐analysis
Authors: Boatin Adeline A. , Cueto Paola D. , Garba Deen L. , Sawyer Michala , James Kaitlyn , Ngonzi Joseph , Lugobe Henry M. , Wylie Blair J. , Adu‐Bonsaffoh Kwame 
Published: July 2024

AbstractObjectiveThe objective of this study is to determine the proportion of women undergoing trial of labour after caesarean (TOLAC) and vaginal birth after caesarean (VBAC) in Sub‐Saharan Africa (SSA), and to estimate associated adverse events.MethodsWe searched PubMed, MEDLINE, CAB, EMBASE and African‐specific databases from 1966 to July 2023, including SSA studies reporting on women with previous caesarean section (CS). We extracted data on study design, planned (TOLAC versus elective repeat CS (ERCS)) and actual delivery mode, and adverse outcomes. We calculated mean TOLAC and VBAC proportions, and pooled proportion of adverse events, comparing between TOLAC and ERCS where available. We assessed bias using the methodological index for nonrandomized studies.ResultsFrom 62 studies with 36 611 births, the estimated proportion undergoing TOLAC and achieving VBAC, adjusted for study variability, were 79% (95% confidence interval [95% CI]: 74%, 85%) and 47% (95% CI: 42%, 51%), respectively, for all births. Mean estimated uterine rupture proportion and maternal mortality were 2.1% (95% CI: 1.1%, 3.2%) and 0.1% (95% CI: 0.02%, 0.2%) respectively. We found no differences between TOLAC and ERCS for uterine rupture (1.2% vs. 0.2%, pooled odds ratio [OR]: 1.54; 95% CI: 0.63, 3.8) or maternal mortality (0.3% vs. <0.1%, pooled OR: 0.77; 95% CI: 0.30, 2.0), respectively. However perinatal mortality was higher with TOLAC compared to ERCS (5% vs. 1%; pooled OR: 3.3; 95% CI: 1.5, 6.9).DiscussionWe found high proportions of women undergoing TOLAC and moderate proportions of successful VBAC across SSA, with a higher perinatal mortality associated with TOLAC. Few studies reported on adverse outcomes and used inconsistent definitions. Further research is needed to understand outcomes in this population of women in these settings.RegistrationThe study protocol was registered with PROSPERO (CRD42020175434).
Risk factors for non‐previa placenta accreta spectrum in pregnancies conceived through frozen embryo transfer during a hormone replacement cycle in Japan
Authors: Matsuo Seiko , Kotani Tomomi , Tano Sho , Ushida Takafumi , Imai Kenji , Nakamura Tomoko , Osuka Satoko , Goto Maki , Osawa Masami , Asada Yoshimasa , Kajiyama Hiroaki 
Published: July 2024

AbstractPurposeNon‐previa placenta accreta spectrum (PAS) is associated with assisted reproductive technology (ART), particularly frozen embryo transfer during hormone replacement therapy (HRC‐FET). We especially aimed to evaluate the prevalence and risk factors for non‐previa PAS in HRC‐FET pregnancies.MethodsOverall, 279 women who conceived through ART at three ART facilities and delivered at a single center were included in this retrospective study. Data regarding endometrial thickness at embryo transfer, previous histories, and type of embryo transfer—HRC‐FET, frozen embryo transfer during a natural ovulatory cycle (NC‐FET), and fresh embryo transfer (Fresh‐ET)—were collected. Univariable logistic regression analyses were conducted.ResultsThe prevalence of non‐previa PAS was 27/192 (14.1%) in the HRC‐FET group and 0 (0.0%) in both the NC‐FET and Fresh‐ET groups. Significantly high odds ratio [95% confidence interval] of non‐previa PAS was associated with a history of artificial abortion (6.45 [1.98–21.02]), endometrial thickness <8.0 mm (6.11 [1.06–35.12]), resolved low‐lying placenta (5.73 [2.13–15.41]), multiparity (2.90 [1.26–6.69]), polycystic ovarian syndrome (2.62 [1.02–6.71]), and subchorionic hematoma (2.49 [1.03–6.04]).ConclusionsA history of artificial abortion, endometrial thickness <8.0 mm, and resolved low‐lying placenta may help in antenatal detection of a high‐risk population of non‐previa PAS in HRC‐FET pregnancies.
Interval observer design for unobservable switched nonlinear partial differential equation systems and its application
Authors: Song Xiaona , Peng Zenglong , Song Shuai , Stojanovic Vladimir 
Published: July 2024

SummaryThis paper designs an interval observer for switched nonlinear partial differential equation (PDE) systems. Initially, persistent dwell‐time switching rules are used to model switched PDE systems with fast and slow switching phenomena. Next, for unobservable systems caused by uncertainties, the interval observer for the target PDE systems is proposed by utilizing unknown but bounded information of the initial states, boundary conditions, external disturbances, and measurement noises. Subsequently, by utilizing the estimated state's upper and lower bounds, an interval observer‐based control strategy is devised to stabilize the studied systems, and sufficient conditions to ensure the stability of the target systems and the observation error dynamics are provided. Furthermore, the designed interval observer is employed to detect sensor failures in the presence of various uncertainties. Finally, two examples, including the lithium‐ion battery's temperature estimation and fault detection, are utilized to demonstrate the effectiveness of the obtained methods.
Practical prescribed‐time tracking control of unknown nonlinear systems: A low‐complexity approach
Authors: Xie Haixiu , Zhang Jin‐Xi , Jing Yuanwei , Chen Jiqing , Dimirovski Georgi M. 
Published: July 2024

AbstractThis article is concerned with the trajectory tracking control problem for the nonlinear systems in the sense of the predefined settling time and accuracy. In contrast with the existing works, we focus on the cases where the system dynamics, its bounding functions, the unmatched disturbances, and the time‐varying parameters are totally unknown; the derivatives of the desired trajectory are not required to be available. They significantly challenge the identification and/or approximation‐based control solutions. To overcome this obstacle, a novel robust prescribed performance control approach via state feedback is put forward in this article. It not only ensures the natural satisfaction of the specific initial condition but also realizes a full‐time performance specification for trajectory tracking. Furthermore, for the case of unmeasured state variables, an output‐feedback control approach is further derived by adopting an input‐driven filter and conducting trivial changes on the design procedure. Moreover, both approaches exhibit significant simplicity, without the needs for parameter identification, function approximation, disturbance estimation, derivative calculation, or command filtering. Three simulation studies are conducted to clarify and verify the above theoretical findings.
State‐dependent dynamic tube MPC: A novel tube MPC method with a fuzzy model of disturbances
Authors: Surma Filip , Jamshidnejad Anahita 
Published: July 2024

AbstractMost real‐world systems are affected by external disturbances, which may be impossible or costly to measure. For instance, when autonomous robots move in dusty environments, the perception of their sensors is disturbed. Moreover, uneven terrains can cause ground robots to deviate from their planned trajectories. Thus, learning the external disturbances and incorporating this knowledge into the future predictions in decision‐making can significantly contribute to improved performance. Our core idea is to learn the external disturbances that vary with the states of the system, and to incorporate this knowledge into a novel formulation for robust tube model predictive control (TMPC). Robust TMPC provides robustness to bounded disturbances considering the known (fixed) upper bound of the disturbances, but it does not consider the dynamics of the disturbances. This can lead to highly conservative solutions. We propose a new dynamic version of robust TMPC (with proven robust stability), called state‐dependent dynamic TMPC (SDD‐TMPC), which incorporates the dynamics of the disturbances into the decision‐making of TMPC. In order to learn the dynamics of the disturbances as a function of the system states, a fuzzy model is proposed. We compare the performance of SDD‐TMPC, MPC, and TMPC via simulations, in designed search‐and‐rescue scenarios. The results show that, while remaining robust to bounded external disturbances, SDD‐TMPC generates less conservative solutions and remains feasible in more cases, compared to TMPC.
Distributed optimal consensus via PI regulation for high‐order nonlinear agents over directed networks
Authors: Wu Wenqiang , Xu Hongyu , Wang Qingling 
Published: July 2024

AbstractThis paper studies the optimal consensus problem of high‐order nonlinear agents under digraphs by PI regulation. A new type of adaptive PI variables is proposed for the first time, which is independent of the global information of graphs and complex dynamics. With the proposed variables, a key lemma is derived to transform the optimal consensus problem into a regulation problem, such that classical control techniques are used to regulate the adaptive PI variables for more complex dynamics. We also develop a new kind of distributed control algorithms based on the adaptive PI variables, Nussbaum‐type functions, and neural networks (NN). The proposed algorithms achieve the optimal consensus for high‐order nonlinear agents with nonidentical unknown control directions, bounded disturbances, and input saturation over weight‐unbalanced directed networks. Finally, a simulation example is provided to illustrate the effectiveness of the proposed algorithms.
Values‐based food procurement: Black farmers and structural racism in New York State
Authors: Gilbert‐Overland Jessica L. 
Published: July 2024

AbstractResponding to growing calls for system dynamics (SD) research to engage with structural racism, this article examines the barriers that Black farmers in New York State face and explores values‐based public institutional food procurement (VBFP) as one possible solution for overcoming these barriers. Combining a qualitative data analysis with causal loop diagrams, this analysis reveals that ongoing structural racism generates (1) structural disconnects between Black farmers' and public institutions' supply chains that inhibit their integration; and (2) procurement policies that create new, rather than addressing existing, barriers for Black farmers. VBFP initiatives' potential to support Black farmers is thus dependent upon dismantling structural racism. In addition, this article advances SD supply chain research by examining one effort to align supply chains with social and environmental values and demonstrates how causal loop diagrams, with their emphasis on system structure, reveal why values‐based supply chain efforts in general often struggle. © 2024 System Dynamics Society.
Minding the abstraction gap: approaches supporting implementation
Authors: Black Laura J. , Greer Donald R. 
Published: July 2024

AbstractRegardless of insights gained from building and analyzing dynamic models, the only strategies people can act on are those in their heads. The strategies people internalize are related to their perceived capacities to act—the verbs they believe they can do. If we want others to implement model‐informed policies, then we must connect model abstractions with new situated, concrete actions stakeholders can take. We can emphasize opportunities to act with SD representations, navigating levels of abstraction cleanly, identifying flows as verbs, and choosing variable names that signal who is acting. By drawing on social‐science theories as we offer our grammar of accumulations, activities, and relationships in the language of actions accessible to stakeholders, we help connect experiential understandings to richer, dynamic explanations people can internalize and so discover situated steps to implement policies informed by modeling. © 2024 The Author(s). System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.
Long‐Durability, Surfactant‐Free, and Bifunctional Ir‐Doped Pt3Co/MWCNTs Electrocatalysts towards ORR and OER in Acidic Media
Authors: Wang Qiang , Li Chuang , Li Guangwei , Li Xiao , Luo Sai , Xing Danmin , Liang Changhai 
Published: July 2024

AbstractDeveloping cost‐effective, high‐performance, and durable electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is pivotal for advancing hydrogen energy conversion and storage technologies. Simultaneously, establishing scalable methods for their production is essential for the widespread adoption of these renewable energy solutions. In this study, we present a successful large‐scale synthesis of surfactant‐free iridium‐doped Pt−cobalt nanoparticles supported on multiwalled carbon nanotubes (Ir−Pt3Co/MWCNTs). This composite demonstrates significantly enhanced ORR and OER activity compared to commercial Pt/C and IrO2 in acidic environments. The Ir−Pt3Co/MWCNTs catalyst composite exhibits a low overpotential of 357 mV at 10 mA cm−2 and a remarkable mass activity of 0.594 A/mgPt. Investigating the influence of Ir doping content on ORR and OER, we found that Pt3Co0.6Ir0.4/MWCNTs showcased the most superior activity in both reactions. We present a reproducible protocol for the synthesis of surfactant‐free Ir−Pt3Co nanoparticles supported on MWCNTs, yielding a bifunctional catalyst capable of efficiently catalyzing both ORR and OER with outstanding efficiency and stability in acidic media. Detailed X‐ray photoelectron spectroscopy (XPS) analysis elucidates the electron transfer between atoms, optimizing the electronic structure and adjusting the position of the d‐band. This optimization enhances the electrocatalytic activity and structural stability of the catalysts, contributing to their superior performance in ORR and OER.
Comparison of Polysaccharide Profiles of Different Seaweeds Based on Ion Chromatography and Ultrahigh‐Performance Liquid Chromatography
Authors: Fan Jing , Gu Donglin , Xv Weiyi , Zhou Tingting , Chen Anzhen , Lu Jingguang , Wang Ying , Jin Hongyu , Wei Feng , Ma Shuangcheng 
Published: July 2024

ABSTRACTIn traditional Chinese medicine research, seaweeds used for drug and health food development mainly refer to Sargassum pallidum (Turn.) C. Ag. (SP) and Sargassum fusiforme (Harv.) Setch. (SF). In the Chinese Pharmacopoeia, polysaccharides are the main quality control indicators. The total sugar content is determined by the anthrone–sulfuric acid method to evaluate the quality of seaweeds. However, this method cannot reflect the structural characteristics of seaweed polysaccharides and cannot distinguish among different seaweed varieties. Given this, to comprehensively evaluate the quality of different seaweeds, this study conducted a thorough analysis of the primary structure of polysaccharides in 11 batches of SF and 7 batches of SP. The neutral sugar content was determined by the anthrone–sulfuric acid colorimetric method, weight average molecular weight (Mw) by high‐performance size exclusion chromatography coupled with multi‐angle laser light scattering and refractive index detector method, sulfate content by ion chromatography and monosaccharide composition by ultrahigh‐performance liquid chromatography method, while also using professional software for statistical and similarity analysis. The results showed significant differences (p < 0.05) in neutral sugar content and Mw between S. fusiforme polysaccharides and S. pallidum polysaccharides, which can be used to distinguish SF and SP. The monosaccharide composition fingerprint was analyzed using chemometric methods, and it was found that fucose and glucose could serve as differential markers to distinguish SF and SP. This study further deepens the understanding of polysaccharides in seaweeds and more comprehensively evaluates the quality of different seaweeds.
Optimizing Ultrasonic‐Assisted Extraction for Enhanced Yield of Phenolic Compounds and Antioxidant Activity in Cold Brew Coffee
Authors: Boonmee Naruemon , Narkprasom Nukrob , Jaturonglumlert Somkiat , Tandee Kanokwan , Rattanawongwiboon Thitirat , Narkprasom Kanjana 
Published: July 2024

ABSTRACTThis study aimed to identify the best conditions for ultrasonic‐assisted extraction (UAE) of DPPH and phenolic compounds from cold brew coffee using Box‐Behnken Design (BBD) and Response Surface Methodology (RSM). It explored the effects of solid‐liquid ratio (5%–15%), extraction time (40–50 min), and ultrasonic power (70%–80%) on these compounds, finding that all factors significantly influenced the outcomes. Statistical analysis showed the data fit a quadratic polynomial model well, with R2 values of 0.9981 for phenolic compounds and 0.9799 for DPPH radicals. Using 3D surface and contour plots from these models, the optimal extraction conditions for these compounds from cold brew coffee were determined. The highest yields of total phenolic compounds and DPPH radical were obtained when samples were extracted at a 10% solid–liquid ratio, 45 min extraction time, and 75% ultrasonic power. Under these optimal conditions, total phenolic compounds and DPPH radical were 64.10 ± 0.31 gGAE/mL and 61.90 ± 0.14%, respectively, with a maximum caffeine content of 213.13 ± 0.23 mg/L. Gamma irradiation at kGy also reduced cold brew coffee's microbial content. This research may be a new alternative for producing cold brew coffee that will save time and help extend the shelf life.
Low secondary risks for turkey vultures from a sodium nitrite toxic bait for wild pigs
Authors: Foster Justin A. , Kinsey John C. , Lavelle Michael J. , VerCauteren Kurt C. , Snow Nathan P. 
Published: July 2024

AbstractAn acute and orally‐delivered toxic bait for wild pigs (Sus scrofa) containing sodium nitrite (SN) is being developed and tested for potential registration in the U.S. We evaluated oral toxicity of SN and risk of secondary consumption in a common avian scavenger, the turkey vulture (Carthartes aura), by 1) conducting an acute oral toxicity test (LD50) for turkey vultures by oral gavage, and 2) allowing turkey vultures to feed on whole carcasses and digestive tracts of wild pigs that died from consuming SN‐laden bait. Captive tests were conducted during fall 2016 and spring 2017 in the Wild Pig Research Facility at Kerr Wildlife Management Area, Hunt, Texas, USA. We estimated the LD50 of SN for turkey vultures at 659 mg/kg. None of the turkey vultures died or exhibited any symptoms of SN‐toxicity from consuming whole carcasses, or digestive tracts of wild pigs that were poisoned with SN. We concluded that the risks of secondary poisoning to turkey vultures are low, which agrees with previous work on another scavenger, the coyote (Canis latrans). Overall, we found no evidence to suggest that 2 common scavengers would be at risk of acute mortality from consuming wild pigs that were poisoned with SN.
Determination of macro‐ and microelements concentrations by wavelength‐dispersive X‐ray fluorescence spectrometry in the objects of the technogenic ecosystem
Authors: Shtel'makh Svetlana I. , Zhilicheva Alena N. , Vasil'eva Irina E. 
Published: July 2024

AbstractThe wavelength‐dispersive X‐ray fluorescence (WDXRF) spectrometry was applied to determine Na, Mg, Al, P, S, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Ba, and Pb concentrations in the needles of dwarfish spruce Picea canadensis conica and the blue prickly spruce Picea pungens glauca, as well in technogenic soil of Irkutsk city, in which these spruce species grow. All measurements were performed in vacuum using WDXRF spectrometer S8 TIGER produced by Bruker AXS, Germany. The calculated values of instrumental limit of detection (ILD) ranged from 0.5 for Ni to 67 mg/kg for Al for soil certified reference materials (CRMs) such as OOKO151 (light chestnut soil) and from 0.2 for Cu and Ni to 18–24 mg/kg for Na for the plant CRMs such as LB‐1 (birch leaf) and EC‐1 (Canadian waterweed). The repeatability is satisfactory. The values of relative standard deviations (RSDs) do not exceed 15% for soils and available plant material. With calculated T‐statistics, it was found that the WDXRF data do not contain systematic errors. The values of relative discrepancy for WDXRF, total reflection X‐ray fluorescence (TXRF) spectrometry, and atomic emission spectrometry with arc discharge (d.c. arc‐AES) results do not exceed 30% for studied elements.
w1+∞ in 4D gravitational scattering
Authors: Himwich Elizabeth , Pate Monica 
Published: July 2024

Abstract
In four-dimensional asymptotically flat spacetimes, an infinite tower of soft graviton modes is known to generate the symmetry algebra of w1+∞ at tree-level. Here we demonstrate that the symmetry action follows from soft graviton theorems and acts non-trivially on massive scalar particles. By generalizing previous analyses that were specifically tailored to the scattering of massless particles, our results clarify that w1+∞ symmetry is a universal feature of tree-level gravitational scattering in four-dimensional asymptotically flat spacetimes and originates from minimally-coupled gravitational interactions. In addition, we show that the w1+∞ symmetry acts non-diagonally on massive states by mixing an infinite number of conformal families. We also present a concrete example of non-local behavior on the celestial sphere in the presence of massive scattering states.
Mixmaster chaos in an AdS black hole interior
Authors: De Clerck Marine , Hartnoll Sean A. , Santos Jorge E. 
Published: July 2024

Abstract
We derive gravitational backgrounds that are asymptotically Anti-de Sitter, have a regular black hole horizon and which deep in the interior exhibit mixmaster chaotic dynamics. The solutions are obtained by coupling gravity with a negative cosmological constant to three massive vector fields, within an Ansatz that reduces to ordinary differential equations. At late interior times the equations are identical to those analysed in depth by Misner and by Belinskii-Khalatnikov-Lifshitz fifty years ago. We review and extend known classical and semiclassical results on the interior chaos, formulated as both a dynamical system of ‘Kasner eras’ and as a hyperbolic billiards problem. The volume of the universe collapses doubly-exponentially over each Kasner era. A remarkable feature is the emergence of a conserved energy, and hence a ‘time-independent’ Hamiltonian, at asymptotically late interior times. A quantisation of this Hamiltonian exhibits arithmetic chaos associated with the principal congruence subgroup Γ(2) of the modular group. We compute a large number of eigenvalues numerically to obtain the spectral form factor. While the spectral statistics is anomalous for a chaotic system, the eigenfunctions themselves display random matrix behaviour.
Gravitational waves from cosmic superstrings and gauge strings
Authors: Marfatia Danny , Zhou Ye-Ling 
Published: July 2024

Abstract
We perform a phenomenological comparison of the gravitational wave (GW) spectrum expected from cosmic gauge string networks and superstring networks comprised of multiple string types. We show how violations of scaling behavior and the evolution of the number of relativistic degrees of freedom in the early Universe affect the GW spectrum. We derive simple analytical expressions for the GW spectrum from superstrings and gauge strings that are valid for all frequencies relevant to pulsar timing arrays (PTAs) and laser interferometers. We analyze the latest data from PTAs and show that superstring networks are consistent with 32 nHz data from NANOGrav, but are excluded by 3.2 nHz data at 3σ unless the string coupling gs< 0.2 or the strings evolve in only about 10% of the volume of the higher-dimensional space. We also point out that while gauge string networks are excluded by NANOGrav-15 data at 3σ, they are completely compatible with EPTA and PPTA data. Finally, we study correlations between GW signals at PTAs and laser interferometers.