bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kerr black hole energy extraction, irreducible mass feedback, and the effect of captured particles charge
Authors: Rueda J. A. , Ruffini R. 
Published: November 2024

AbstractWe analyze the extraction of the rotational energy of a Kerr black hole (BH) endowed with a test charge and surrounded by an external test magnetic field and ionized low-density matter. For a magnetic field parallel to the BH spin, electrons move outward(inward) and protons inward(outward) in a region around the BH poles(equator). For zero charge, the polar region comprises spherical polar angles $$-60^\circ \lesssim \theta \lesssim 60^\circ $$

-

60
∘

≲
θ
≲

60
∘

and the equatorial region $$60^\circ \lesssim \theta \lesssim 120^\circ $$

60
∘

≲
θ
≲

120
∘

. The polar region shrinks for positive charge, and the equatorial region enlarges. For an isotropic particle density, we argue the BH could experience a cyclic behavior: starting from a zero charge, it accretes more polar protons than equatorial electrons, gaining net positive charge, energy and angular momentum. Then, the shrinking(enlarging) of the polar(equatorial) region makes it accrete more equatorial electrons than polar protons, gaining net negative charge, energy, and angular momentum. In this phase, the BH rotational energy is extracted. The extraction process continues until the new enlargement of the polar region reverses the situation, and the cycle repeats. We show that this electrodynamical process produces a relatively limited increase of the BH irreducible mass compared to gravitational mechanisms like the Penrose process, hence being a more efficient and promising mechanism for extracting the BH rotational energy.
Dynamical and thermodynamical stability of a charged thin-shell wormhole
Authors: Eiroa Ernesto F. , Figueroa-Aguirre Griselda , Peñafiel Miguel L. , Bergliaffa Santiago Esteban Perez 
Published: November 2024

AbstractA study of the dynamical and thermodynamical stability of a charged thin-shell wormhole built by gluing two Reissner–Nordström geometries is presented. The charge on the shell is linearly related to the matter content. For the dynamical stability, a concise inequality is obtained, valid for any barotropic equation of state that relates the pressure with the energy density at the throat. A thermodynamical description of the system is introduced, which leads to the temperature and the electric potentials. Adopting a linear equation of state for the pressure and a definite form for the entropy function, the set of equilibrium configurations that are both dynamically and thermodynamically stable is found.
Destroying the event horizon of cold dark matter-black hole system
Authors: Meng Liping , Xu Zhaoyi , Tang Meirong 
Published: November 2024

AbstractSince the weak cosmic censorship conjecture was proposed, research on this conjecture has been ongoing. This paper explores the conjecture in black holes that are closer to those existing in the real universe (i.e., rotating black holes enveloped by dark matter). In this paper, we obtained a first-order corrected analytical solution for the black hole event horizon through an approximate solution. The validity of the first-order corrected analytical solution will be provided in the appendix. We conduct our study by introducing a test particle and a scalar field into the black hole. Our conclusions show that, in extremal case, both a test particle and a scalar field can disrupt the event horizon of the Kerr-like black hole; in near-extremal case, both a test particle and a scalar field can disrupt the event horizon of the Kerr-like black hole. When cold dark matter is not considered, the conclusion is consistent with previous research.
Outgoing electromagnetic flux from rotating wormholes
Authors: Ertola Urtubey Milos , Pérez Daniela , Romero Gustavo E. 
Published: November 2024

AbstractWe show for the first time that rotating wormholes are capable of emitting a Poynting flux in the process of accreting magnetized matter. To this end, we analyze the Damour–Solodukhin metric describing a Kerr-type wormhole and calculate the electromagnetic flux assuming a specific geometry for the magnetic field contained by the wormhole ergosphere. We find that for highly rotating wormholes a mechanism similar to that of Blandford and Znajek is possible, and the emitted electromagnetic flux is of the same order as for a Kerr black hole.
The alpha particle charge radius, the radion and the proton radius puzzle
Authors: Dahia F. , Lemos A. S. 
Published: November 2024

AbstractRecent measurements of the Lamb shift of muonic helium-4 ions were used to infer the alpha particle charge radius. The value found is compatible with the radius extracted from the analysis of the electron-helium scattering. Thus, the new spectroscopic data put additional empirical bounds on some free parameters of certain physics theories beyond the Standard Model. In this paper, we analyze the new data in the context of large extra-dimensional theories. Specifically, we calculate the influence of the radion, the scalar degree of freedom of the higher-dimensional gravity, on the energy difference between the 2S and 2P levels of this exotic atom. The radion field is related to fluctuations of the volume of the supplementary space. It should be treated as a phenomenologically independent quantity in relation to the tensorial degrees of freedom of the metric within the braneworld scenario. Based on the spectroscopic data of muonic helium, we find constraints for the effective energy scale of the radion as a function of the alpha particle radius. Then, we discuss the implications of these new constraints on the proton radius puzzle. We also establish a new empirical bound for the radion by examining its influence on the isotopic shift in the 2P-2S transition of muonic hydrogen and muonic deuteron. In connection with this discussion, we study the impact of the radion on the tension observed in measurements of the difference between the squared radii of the helion and alpha particle as extracted from muonic and electronic helium isotopes.
Translation and Psychometric Properties of the Persian Version of the Organizational Learning Instrument–Development Stages (OLI‐DS) Instrument in Hospital Units
Authors: Mirzaei Alireza , Kazemi Darabadi Faranak , Havaskar Sahar , Lotfi Azade , Nemati-Vakilabad Reza 
Published: November 2024

Aim: The Organizational Learning Instrument–Development Stages (OLI‐DS) measure hospital units’ readiness to engage in organizational learning. This study aimed to translate and evaluate the psychometric properties of the Persian version of this instrument.Background: Organizational learning is crucial for nurses as it enables them to continuously develop their knowledge, skills, and abilities, enhancing the quality of patient care. However, validated instruments are needed to assess organizational learning in Persian‐speaking healthcare settings.Design: The research was carried out using a cross‐sectional design.Methods: This research study involved 319 clinical nurses selected using convenience sampling. The OLI‐DS tool, consisting of 35 items, underwent a forward–backward translation process to Persian before being utilized for a psychometric analysis. The face, content, and construct validity were used to evaluate the tool’s effectiveness. The quality and accuracy of the measurements were determined by calculating internal consistency and stability reliability. The data were analyzed using SPSS and AMOS software.Results: The intended meaning and clarity of the original English version were preserved in the Persian rendition of the OLI‐DS instrument. The confirmatory factor analysis (CFA) further confirmed the consistency of the Persian version with the proposed four‐factor model, indicating a good fit. The overall instrument had excellent values for Cronbach’s alpha coefficient (α = 0.931), McDonald’s omega (ω = 0.921), coefficient H (H = 0.979), and mean interitem correlation (ρ = 0.278). The convergent and discriminant validity of the four latent factors was found to be good. The stability of the overall OLI‐DS instrument was ICC = 0.942 (95% CI, 0.902–0.955).Conclusion: The Persian version of the OLI‐DS has been validated to evaluate hospital units’ readiness for organizational learning processes. It is a robust tool for assessing their preparedness to participate in and benefit from organizational learning initiatives.Implications for Nursing Management: The robust psychometric validation of the Persian version of the OLI‐DS instrument equips nursing administrators and leaders with a reliable tool. This tool can assess and monitor organizational learning and development in healthcare settings, empowering them to make informed decisions in critical nursing management activities.
Pharmacist Medication Titration Program for Patients With Cardiac Sarcoidosis and Systolic Heart Failure: A Retrospective Cohort Study
Authors: Sykora Daniel , Olson Nicole , Churchill Robert , Kim B. Michelle , Bratcher Melanie , Elwazir Mohamed , Young Kathleen , Ryan Sami , Brodin Michelle , Anderson Jan , Saunders Jeremiah , Abou Ezzeddine Omar , Bois John , Giudicessi John , Cooper Leslie , Rosenbaum Andrew 
Published: November 2024

Background
A multidisciplinary approach improves guideline‐directed medical therapy in systolic heart failure (HF), but its efficacy in patients with HF due to cardiac sarcoidosis is unreported.

Methods and Results

In a retrospective cohort study, we reviewed 848 patients from our institutional cardiac sarcoidosis clinics, identifying those with a cardiac sarcoidosis diagnosis, HF (left ventricular ejection fraction <50%) at index evaluation, and echocardiograms within 90 days and 11 to 36 months. Patients were stratified by participation in a pharmacist‐led medication therapy management (MTM) program for guideline‐directed medical therapy optimization (MTM versus non‐MTM [NMTM]) without randomization. Demographics, left ventricular ejection fraction, guideline‐directed medical therapy (quantified by Kansas City Medical Optimization score), and immunosuppressive therapy were assessed. Primary outcomes included changes in Kansas City Medical Optimization score, left ventricular ejection fraction, and cardiovascular event–free survival (unplanned HF hospitalization, left ventricular assist device /heart transplant, or death). The final cohort included 111 patients (median age, 57 years; 34% women; 64% New York Heart Association class I–II); 43 (39%) were MTM and 68 (61%) were NMTM. Mean Kansas City Medical Optimization score was similar at index evaluation (MTM, 23.2; NMTM, 29.6;
P
=0.83). At follow‐up (median, 16 months), the Kansas City Medical Optimization score increased significantly in both groups (MTM, 23.2 to 74.8;
P
<0.001; NMTM, 29.6 to 58.7;
P
<0.001) but was higher in MTM (
P
=0.001). Mean left ventricular ejection fraction trended toward higher values in MTM (44.4% versus 40.0%,
P
=0.05). The primary clinical outcome occurred in 1 MTM (2.3%) and 16 NMTM (23.5%) patients, with higher risk in NMTM (hazard ratio, 11.97 [95% CI, 1.58–90.54];
P
=0.002).

Conclusions
In this retrospective cohort study, a pharmacist‐led MTM program was associated with favorable guideline‐directed medical therapy optimization and lower risk of adverse cardiovascular outcomes in patients with cardiac sarcoidosis with HF.
Computing With Residue Numbers in High-Dimensional Representation
Authors: Kymn Christopher J. , Kleyko Denis , Frady E. Paxon , Bybee Connor , Kanerva Pentti , Sommer Friedrich T. , Olshausen Bruno A. 
Published: November 2024

Abstract
We introduce residue hyperdimensional computing, a computing framework that unifies residue number systems with an algebra defined over random, high-dimensional vectors. We show how residue numbers can be represented as high-dimensional vectors in a manner that allows algebraic operations to be performed with component-wise, parallelizable operations on the vector elements. The resulting framework, when combined with an efficient method for factorizing high-dimensional vectors, can represent and operate on numerical values over a large dynamic range using resources that scale only logarithmically with the range, a vast improvement over previous methods. It also exhibits impressive robustness to noise. We demonstrate the potential for this framework to solve computationally difficult problems in visual perception and combinatorial optimization, showing improvement over baseline methods. More broadly, the framework provides a possible account for the computational operations of grid cells in the brain, and it suggests new machine learning architectures for representing and manipulating numerical data.
Generalization Guarantees of Gradient Descent for Shallow Neural Networks
Authors: Wang Puyu , Lei Yunwen , Wang Di , Ying Yiming , Zhou Ding-Xuan 
Published: November 2024

Abstract
Significant progress has been made recently in understanding the generalization of neural networks (NNs) trained by gradient descent (GD) using the algorithmic stability approach. However, most of the existing research has focused on one-hidden-layer NNs and has not addressed the impact of different network scaling. Here, network scaling corresponds to the normalization of the layers. In this article, we greatly extend the previous work (Lei et al., 2022; Richards & Kuzborskij, 2021) by conducting a comprehensive stability and generalization analysis of GD for two-layer and three-layer NNs. For two-layer NNs, our results are established under general network scaling, relaxing previous conditions. In the case of three-layer NNs, our technical contribution lies in demonstrating its nearly co-coercive property by utilizing a novel induction strategy that thoroughly explores the effects of overparameterization. As a direct application of our general findings, we derive the excess risk rate of O(1/n) for GD in both two-layer and three-layer NNs. This sheds light on sufficient or necessary conditions for underparameterized and overparameterized NNs trained by GD to attain the desired risk rate of O(1/n). Moreover, we demonstrate that as the scaling factor increases or the network complexity decreases, less overparameterization is required for GD to achieve the desired error rates. Additionally, under a low-noise condition, we obtain a fast risk rate of O(1/n) for GD in both two-layer and three-layer NNs.
Forest Breeze–Cold Pool Interactions Drive Convective Organization over Heterogeneous Vegetation
Authors: Ascher Benjamin D. , Saleeby Stephen M. , Marinescu Peter J. , van den Heever Susan C. 
Published: November 2024

Abstract
Heterogeneous landscapes can influence the development of convection through the generation of thermally driven mesoscale circulations. To assess the impacts of these circulations and their interaction with sea breezes, we simulated convection in an idealized coastal environment using the Regional Atmospheric Modeling System (RAMS). We compared simulations with striped patterns of surface vegetation to those of uniform vegetation to identify the importance of vegetation heterogeneity in impacting convective development. Under dry soil conditions representative of those during the Tracking Aerosol Convection Interactions Experiment (TRACER) and Experiment of Sea Breeze Convection, Aerosols, Precipitation, and Environment (ESCAPE) campaigns in June 2022, we found that these vegetation-induced circulations, referred to in the literature as “forest breezes,” are more important than the sea breeze in determining the location of convection initiation. Convection and precipitation are also found to be favored over forests and suppressed over pasture and suburban landscapes as a result of greater surface sensible heat flux over the forest. Our findings also indicate that forest breezes are important for initiating convection along the boundaries of the forest, but that cold pools may play a key role in propagating the forest breezes toward the center of the forest stripe. In our simulations, the collisions of these breezes in the center of the forest stripe lead to uplift and strong convection there; however, a different width of the forest stripe would alter when the forest breezes collide or whether they collide at all. The presence of these cold pools may therefore impact the “ideal stripe width,” the width of each vegetation stripe which maximizes domain-wide precipitation.
Financial Vulnerability and Risks to Growth in Emerging Markets
Authors: Acharya Viral V. , Bhadury Soumya , Surti Jay 
Published: November 2024

This article introduces a new financial vulnerability index for emerging market economies by exploiting key differences in their business cycles relative to those of advanced economies. Information on the domestic price of risk, cost of dollar hedging and market-based measures of bank vulnerability combine to generate indexes significantly more effective in capturing macro-financial vulnerability and stress compared to those based on information in trade and global factors. Our index significantly augments early warning surveillance capacity, as evidenced by out-of-sample forecasting gains around a majority of turning points in gross domestic product (GDP) growth, relative to distributed lag models that are augmented with information from macro-financial indexes that are custom-built to optimise such forecasts. JEL Codes: C53, E32, E44
The effects of filling method on silicone rubber composites filled with SiO2 and TiO2
Authors: Li Yanqi , Zhang Jiaqiang , Tang Qiaolin , Peng Qiang , Zhu Feng , Kang Ming 
Published: November 2024

Silica (SiO₂) serves as a reinforcing filler, while titanium dioxide (TiO₂) functions as a functional filler, imparting exceptional mechanical strength and UV resistance to silicone rubber. However, compatibility issues may arise when both fillers are incorporated into silicone rubber. This study explores potential solutions through processing methods, specifically by comparing the effects of graded filling and mixed filling on the properties of silicone rubber. Field emission scanning electron microscopy reveals that the mixed filling method promotes a more uniform dispersion of fillers, leading to enhanced performance. Curing tests indicate that the effect of the filling method on the curing processing performance of silicone rubber is negligible. Tensile test results reveal that, compared to the graded filling system, the mixed filling system improves the tensile strength and elongation at break of the silicone rubber composites by 13% and 13.4%, respectively, while simultaneously reducing the Mullins effect, thereby enhancing material stability. Thermogravimetric analysis (TGA) and differential thermal analysis (DTG) results indicate that the uniform dispersion achieved through mixed filling optimizes thermal transfer pathways, resulting in superior thermal stability compared to graded filling. Ultraviolet (UV) spectroscopy results demonstrate that composites containing added TiO₂ exhibit almost zero transmittance in the UV range of 200-400 nm, underscoring their excellent UV resistance; the mixed filling method provides superior UV protection compared to the graded fill method. In summary, for the dual-filler system of SiO₂ and TiO₂, the mixed filling approach enhances filler compatibility by improving dispersion, thereby elevating material performance and broadening potential applications.
Multi-indication Evidence Synthesis in Oncology Health Technology Assessment: Meta-analysis Methods and Their Application to a Case Study of Bevacizumab
Authors: Singh Janharpreet , Anwer Sumayya , Palmer Stephen , Saramago Pedro , Thomas Anne , Dias Sofia , Soares Marta O , Bujkiewicz Sylwia 
Published: November 2024

Background Multi-indication cancer drugs receive licensing extensions to include additional indications, as trial evidence on treatment effectiveness accumulates. We investigate how sharing information across indications can strengthen the inferences supporting health technology assessment (HTA). Methods We applied meta-analytic methods to randomized trial data on bevacizumab, to share information across oncology indications on the treatment effect on overall survival (OS) or progression-free survival (PFS) and on the surrogate relationship between effects on PFS and OS. Common or random indication-level parameters were used to facilitate information sharing, and the further flexibility of mixture models was also explored. Results Treatment effects on OS lacked precision when pooling data available at present day within each indication separately, particularly for indications with few trials. There was no suggestion of heterogeneity across indications. Sharing information across indications provided more precise estimates of treatment effects and surrogacy parameters, with the strength of sharing depending on the model. When a surrogate relationship was used to predict treatment effects on OS, uncertainty was reduced only when sharing effects on PFS in addition to surrogacy parameters. Corresponding analyses using the earlier, sparser (within and across indications) evidence available for particular HTAs showed that sharing on both surrogacy and PFS effects did not notably reduce uncertainty in OS predictions. Little heterogeneity across indications meant limited added value of the mixture models. Conclusions Meta-analysis methods can be usefully applied to share information on treatment effectiveness across indications in an HTA context, to increase the precision of target indication estimates. Sharing on surrogate relationships requires caution, as meaningful precision gains in predictions will likely require a substantial evidence base and clear support for surrogacy from other indications. Highlights We investigated how sharing information across indications can strengthen inferences on the effectiveness of multi-indication treatments in the context of health technology assessment (HTA). Multi-indication meta-analysis methods can provide more precise estimates of an effect on a final outcome or of the parameters describing the relationship between effects on a surrogate endpoint and a final outcome. Precision of the predicted effect on the final outcome based on an effect on the surrogate endpoint will depend on the precision of the effect on the surrogate endpoint and the strength of evidence of a surrogate relationship across indications. Multi-indication meta-analysis methods can be usefully applied to predict an effect on the final outcome, particularly where there is limited evidence in the indication of interest.
The impact of gadolinium-based contrast agents on 1H-magnetic resonance spectroscopy in normal brain area: a preliminary study
Authors: That Nam Anh Ton , Van Nguyen Thi Tuong , Thanh Thao Nguyen 
Published: November 2024

Background Giving contrast material before 1H-magnetic resonance spectroscopy (MRS) could enhance the precision of locating the lesion of interest. However, evidence indicates that contrast material might influence the outcomes of MRS. Purpose To verify the effect of gadolinium-based contrast agent (GBCA) on MRS in normal white matter. Material and Methods A total of 34 patients were referred for brain magnetic resonance imaging (MRI) with GBCAs, and they underwent single-volume MRS before and after administering contrast material. Those patients had the MRS voxel placed at the right frontal normal white matter, which remained consistent across all examinations. Measurements were taken for the integral concerning N-acetyl aspartate (NAA), choline (Cho), creatine (Cr and Cr2), and myo-inositol (Ins) in all examinations. Results NAA ( P = 0.0313) and Cho ( P = 0.0094) had a significant decrease in their integral after intravenous GBCA administration. No significant differences were found between the pre- and post-contrast MRS studies for Cr, Cr2, and Ins. Conclusion Intravenous GBCA can alter NAA and Cho integrals in normal white matter. Therefore, brain 1H-MRS should precede intravenous GBCA administration to avoid the potential impact of contrast material on peak integrals.