bluuebunny/crossref_metadata_2025 huggingface dataset:
Qualitative properties of fractional convolution elliptic and parabolic operators in Besov spaces
Authors: Shakhmurov Veli , Shahmurov Rishad
Published: June 2024

The maximal $$B_{p,q}^{s}$$

B

p
,
q

s

-regularity properties of a fractional convolution elliptic equation is studied. Particularly, it is proven that the operator generated by this nonlocal elliptic equation is sectorial in $$ B_{p,q}^{s}$$

B

p
,
q

s

and also is a generator of an analytic semigroup. Moreover, well-posedeness of nonlocal fractional parabolic equation in Besov spaces is obtained. Then by using the $$B_{p,q}^{s}$$

B

p
,
q

s

-regularity properties of linear problem, the existence, uniqueness of maximal regular solution of corresponding fractional nonlinear equation is established.
A novel quasi-static compression test set-up with micron order accuracy for small specimens
Authors: Daras Nicholas , Cloete Trevor J. , Nurick Gerald N.
Published: June 2024

Accurate displacement measurements during compression tests on small specimens using large standard universal testing machines are adversely affected by the compliance of the apparatus. The influence of compliance becomes more acute when conducting tests on quasi-brittle materials, such as cortical bone, that exhibit low failure strains and for which accurate modulus values are required. This paper presents a custom compression test set-up (i.e., a subpress) that facilitates routine quasi-static compression tests on small specimens by eliminating the effect of testing machine compliance on the results. The displacement of the compression test set-up was recorded using a combination of Hall effect sensors and multipole magnetic strips, which offers a resolution of less than one micron. The results of quasi-static compression tests on small polymer specimens are reported where the displacements were measured using the custom compression test set-up, the integrated displacement measurement system of a universal testing machine and a visual extensometer. Additional tests on cortical bone specimens demonstrate the effectiveness of the compression test set-up. Based on the results, the compression test set-up appeared to yield more consistent and accurate measurements compared to both the integrated measurement system of a universal testing machine and a visual extensometer. Novel data regarding the incipient fracture of cortical bone were obtained. The compression test set-up allows for the routine testing of a large number of bone specimens with micron accuracy in a short time frame, thus reducing the effects of degradation on biological specimens.
Viscoelastic Rheological Modelling of the Lateral Dynamic Response of Ballasted Railway Tracks
Authors: Farooq Hafsa , Nimbalkar Sanjay , Punetha Piyush , Sheng Daichao
Published: June 2024

This article presents a novel methodology for evaluating the response of ballasted railway tracks under train-induced loading along lateral directions. The main focus of this study is the development of a computational technique that can capture the lateral response of ballasted railway tracks, which has been ignored in past studies. The proposed approach employs a viscoelastic rheological track model in which three substructure layers are simulated using discrete masses, Hooke’s (springs) and Newtonian elements (dampers). The methodology is successfully validated against the data from experimental and analytical investigations published in the literature. Subsequently, parametric investigations are conducted to study the influence of axle load, train speed, and granular layer thickness on the track response. The results indicate that as the axle load (20 to 40 t) and train speed (70 to 200 km/h) are increased, there is a corresponding increase in track displacements (both lateral and vertical) by 100% and 26.2%, respectively. However, an increase in the granular layer thickness (0.1 to 0.75 m) reduces ballast top displacement (lateral and vertical) by 20–30%. The results demonstrate the capability of the proposed computational approach to capture the transient response of railway tracks and the influence of neighbouring layer properties on the track response. The proposed methodology can be helpful to practising railway engineers for assessing the performance of ballasted railway tracks along lateral directions.
Aging trajectories of subscales in higher-level functional capacity among community-dwelling older Japanese adults: the Otassha study
Authors: Kawai Hisashi , Imamura Keigo , Ejiri Manami , Fujiwara Yoshinori , Ihara Kazushige , Hirano Hirohiko , Sasai Hiroyuki , Obuchi Shuichi
Published: June 2024

Background

Maintaining higher-level functional capacity is important for independent living in older age. The aging trajectory of the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC) has three patterns; however, the subscale patterns are unclear.

Aims

This study aimed to clarify the aging trajectory patterns of the TMIG-IC subscales among community-dwelling older Japanese.

Methods

Participants were 3,169 community-dwelling older Japanese who participated in the 2012–2022 mail survey of the Otassha study. The aging trajectory patterns of the TMIG-IC total and subscale scores for those aged 65–90 years were identified using group-based trajectory modeling. Further, the combination frequency of the subscale trajectory patterns was determined.

Results

Three patterns were identified: early-onset decreasing, late-onset decreasing, and high-stable.

Discussion

The instrumental activities of daily living (IADL) trajectory was maintained until approximately 80 years of age; however, chronic disease prevailed the most in the early-onset decreasing pattern. The early-onset decreasing pattern of intellectual activity (IA) was present in 25% of participants, showing impaired IA from 65 years of age. The late-onset decreasing pattern of social roles (SR) was present in 30% of participants, showing a sharp decline compared to other subscales. For many people, the patterns of decrease in SR and IA overlapped.

Conclusions

To maintain higher-level functional capacity, interventions that include disease management and prevention of decline in IADL and increase the awareness of the social support provided throughout old age and interventions for people with an early decline in IA should be implemented.
Getting old in the desired gender: a systematic review on aging diseases in transgender people
Authors: Ceolin C. , Papa M. V. , Scala A. , Sergi G. , Garolla A.
Published: June 2024

Introduction

The growing demographic presence of the transgender (TGD) population has sparked an increase in clinical investigations focusing on the impacts of gender-affirming hormone therapy (GAHT) in adults with gender dysphoria. Despite this surge in studies, there remains a significant gap in the literature regarding the health status of older TGD individuals. This review aims to assess prevalent pathological conditions within the TGD population, specifically concentrating on aging-related diseases investigated to date.

Methods

A systematic search across Embase Ovid, Scopus, PubMed, Cochrane Library, and Web of Science databases was conducted to identify articles reporting on the aging process in TGD individuals. Methodological quality was evaluated using Newcastle–Ottawa Scale (NOS) scores.

Results

Initial database searches yielded 12,688 studies, which were refined to 18 through elimination of duplicates and title/abstract review. Following a comprehensive appraisal, nine studies were included in the systematic review. These articles, published between 2017 and 2023, involved a total of 5403 participants. The evidence indicates a noteworthy percentage of the TGD population being at risk for cardiovascular diseases, experiencing depression or disability, and demonstrating hesitancy toward major recommended screening programs.

Conclusions

Limited studies on older TGD individuals highlight not only an organic risk of chronic diseases but also a cognitive/psychiatric risk that should not be underestimated. Further research is imperative to deepen our understanding of the pathophysiological mechanisms involved in the health challenges faced by older TGD individuals.
Iron Oxide Direct Reduction and Iron Nitride Formation Using Ammonia: Review and Thermodynamic Analysis
Authors: Triana Tiara , Brooks Geoffrey A. , Rhamdhani M. Akbar , Pownceby Mark I.
Published: June 2024

The steel industry is one of the main contributors to global greenhouse gas emissions, responsible for about 7 to 9% of the world’s total output. The steel sector is under pressure to move toward net-zero emissions by reducing its consumption of coke as the main method of reducing iron-rich feed materials to iron. Due to its well-developed synthesis process, high supply chain, straightforward handling technologies, and highly developed long-standing infrastructure, ammonia has the potential to become a replacement for coke as a future iron ore reductant. This work reviews previous research on ammonia direct reduction of iron oxides and the possible formation of iron nitrides. A thermodynamic assessment using FactSage 8.2 thermochemical software was carried out examining the behavior of ammonia gas as the reductant upon heating, detailed evaluations of the stable phases present under different reaction conditions and using different feed materials, and the formation and stability of iron nitride phases. The results suggest that the reduction of hematite with ammonia occurs in two steps below 570 °C and three steps above 570 °C. The ratio of Fe2O3/NH3 was predicted to affect the reduction reactions by promoting a greater reduction degree and simultaneously lowering the initial temperature needed for reduction, while the excess gas concentration can suppress FeO formation. A predominance area diagram was developed showing the main areas of stable phases as a function of the partial pressure of NH3 and temperature. The formation of iron nitrides during the process was predicted and these were not expected to cause issues for the formation of iron due to their instability under the conditions studied. This analysis can be used to inform further experimental studies regarding ammonia reduction of iron oxide.

Graphical Abstract
Discourses on religion in research that focuses on students’ perspectives
Authors: Franzén Johnson Anna , Lilja Annika , Osbeck Christina
Published: June 2024

In this article, the aim is twofold: firstly, to explore, through a systematic literature review, what discourses on religion may be identified in previous research that focuses on students’ perspectives, and secondly, to discuss this in relation to research concerning challenges and opportunities in Scandinavian religious education (RE) and classroom negotiations, which is presented as a background to and scientific landscape for the study. Seven discourses relating to students’ understanding of religion have been identified in the text sample from the systematic review, religion as: threatening, a relic, needing to be tolerated, truth claims, plastic, a source of existential curiosity, and security and comfort. The findings show how these discourses together constitute a broader repertoire of discourses on religion than can be found in the Scandinavian RE classroom research presented as a frame for the study, especially when taking into account current orders of discourse and dominance structures. As stressed by discourse theory and sociocultural perspectives on learning, having access to broad repertoires of discourses on religion provides a basis for more nuanced ways of thinking about religion. It is vital that teachers are aware of this and can challenge dominant discourses and broaden existing repertoires. An important step in such a direction is an awareness of discourses on religion, such as the seven presented here, which may potentially be present in the classroom, even in practices other than the ones these discourses emanated from.
Influence of design variables on seismic performance of unitized curtain walls: a parametric experimental study
Authors: Bianchi Simona , Lori Guido , Hayez Valerie , Overend Mauro , Manara Giampiero
Published: June 2024

Creating safer and more resilient building facades has become a primary concern in contemporary design, particularly in earthquake-prone regions, where there is a potentially high impact on financial, social and environmental losses. Glazed curtain wall systems are widely used in modern architecture. Yet, despite decades of research efforts aimed at enhancing the understanding of their seismic behaviour, it is not clear how design choices affect the response of glazed facades. This is crucial given the wide range of glass, framing and joint variations that are at our disposal. With a focus on unitized curtain walls, this paper provides insights into the influence of design variables on façade seismic response by means of an extensive experimental campaign and an associated parametric study to test alternative designs under both quasi-static and dynamic loading conditions. The variables considered included variations in unit dimensions, glass and joint aspect ratios, joint and framing detailing, and support conditions. This research delves into a statistical analysis of the experimental results, in order to define parameters such as glass and façade unit rotations, frame elongations and distortions, utilization factors at different intensity levels. The results provide insights that guide façade design decisions for achieving desired seismic performance levels.
Microscopic deformation mechanism and characteristics of carbonaceous slate during the creep process
Authors: Yang Hucheng , Li Peng , Su Shengrui , Chen Jianxun
Published: June 2024

Carbonaceous slate exhibits a significant creep deformation that seriously affects the construction and operation of underground projects. To investigate the microstructural changes characteristics and reveal the microscopic deformation mechanism of the carbonaceous slate during the creep process, multiple methods were performed, including the triaxial creep test, SEM and MIP. The following conclusions were drawn: The rock samples underwent three stages during the creep test: microporosity closure at a low-stress level, material densification at an intermediate stress level, and microcracks emerging and expanding to failure at the high stress. The creep deformation was particularly significant in the first and third processes. The lamellar particles are compressed or bent under stress in parallel and vertical directions, showing the anisotropic properties of deformation. The deformation of the rock sample is related to the angle between the bedding and the orientation of major principal stress, and the effect of the anisotropy decreases with the increased stress level. The sprouting and expansion of microfractures occur at high-stress levels, showing pressure dissolution of mineral particles, migration of very fine particles, and cement damage between lamellar particles. Finally, the horizontal samples formed a combined rupture surface composed of the laminar surface and the fracture surface intersecting it, showing brittle damage, while the vertical samples formed a fracture surface parallel to the laminar surface, showing a ductile damage pattern. Those results could provide the basis for a further understanding of the mechanical properties of carbonaceous slate and the improvement of its creep model and parameters. It was significant for the stability analysis and deformation prediction of engineering structures using numerical simulation.
Optimization of Wet-Spun PEDOT:PSS Fibers for Thermoelectric Applications Through Innovative Triple Post-treatments
Authors: Deng Yu-Yu , Shi Xiao-Lei , Wu Ting , Yue Yicheng , Liu Wei-Di , Li Meng , Yue Fang , Huang Pei , Liu Qingfeng , Chen Zhi-Gang
Published: June 2024

Owing to the high flexibility, low thermal conductivity, and tunable electrical transport property, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) exhibits promising potential for designing flexible thermoelectric devices in the form of films or fibers. However, the low Seebeck coefficient and power factor of PEDOT:PSS have restricted its practical applications. Here, we sequentially employ triple post-treatments with concentrated sulfuric acid (H2SO4), sodium borohydride (NaBH4), and 1-ethyl-3-methylimidazolium dichloroacetate (EMIM:DCA) to enhance the thermoelectric performance of flexible PEDOT:PSS fibers with a high power factor of (55.4 ± 1.8) μW m−1 K−2 at 25 °C. Comprehensive characterizations confirm that excess insulating PSS can be selectively removed after H2SO4 and EMIM:DCA treatments, which induces conformational changes to increase charge carrier mobility, leading to enhanced electrical conductivity. Simultaneously, NaBH4 treatment is employed to adjust the oxidation level, further optimizing the Seebeck coefficient. Additionally, the assembled flexible fiber thermoelectric devices show an output power density of (60.18 ± 2.79) nW cm−2 at a temperature difference of 10 K, proving the superior performance and usability of the optimized fibers. This work provides insights into developing high-performance organic thermoelectric materials by modulating polymer chains.

Graphical Abstract
Luteolin for neurodegenerative diseases: a review
Authors: Jayawickreme Dunuvilla Kavindi , Ekwosi Cletus , Anand Apurva , Andres-Mach Marta , Wlaź Piotr , Socała Katarzyna
Published: June 2024

Neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, and multiple sclerosis affect millions of people around the world. In addition to age, which is a key factor contributing to the development of all neurodegenerative diseases, genetic and environmental components are also important risk factors. Current methods of treating neurodegenerative diseases are mostly symptomatic and do not eliminate the cause of the disease. Many studies focus on searching for natural substances with neuroprotective properties that could be used as an adjuvant therapy in the inhibition of the neurodegeneration process. These compounds include flavonoids, such as luteolin, showing significant anti-inflammatory, antioxidant, and neuroprotective activity. Increasing evidence suggests that luteolin may confer protection against neurodegeneration. In this review, we summarize the scientific reports from preclinical in vitro and in vivo studies regarding the beneficial effects of luteolin in neurodegenerative diseases. Luteolin was studied most extensively in various models of Alzheimer’s disease but there are also several reports showing its neuroprotective effects in models of Parkinson’s disease. Though very limited, studies on possible protective effects of luteolin against Huntington’s disease and multiple sclerosis are also discussed here. Overall, although preclinical studies show the potential benefits of luteolin in neurodegenerative disorders, clinical evidence on its therapeutic efficacy is still deficient.

Graphical abstract
Patient and Public Perceptions in Canada About Decentralized and Hybrid Clinical Trials: “It’s About Time we Bring Trials to People”
Authors: Richards Dawn P. , Queenan John , Aasen-Johnston Linnea , Douglas Heather , Hawrysh Terry , Lapenna Michael , Lillie Donna , McIntosh Emily I. , Shea Jenna , Smith Maureen , Marlin Susan
Published: June 2024

Background

Little is known about patient and the public perspectives on decentralized and hybrid clinical trials in Canada.

Methods

We conducted an online survey (English and French) promoted on social media to understand perspectives of people in Canada about decentralized and hybrid clinical trials. The survey had two sections. We co-produced this project entirely with patient, caregiver, and family partners.

Results

The survey had 284 (14 French) individuals who started or completed Section 1, and 180 (16 French) individuals who started or completed Section 2. People prefer to have options to participate in clinical trials where aspects are decentralized or hybridized. 79% of respondents preferred to have options related to study visits. There were concerns about handling adverse events or potential complications in decentralized trials, however, communication options such as a dedicated contact person for participants was deemed helpful. Most respondents were amenable to informed consent being done at a satellite site closer to home or via technology and were split on privacy concerns about this. Most preferred travel to a site within an hour, depending on what the trial was for or its impact on quality of life. Due to the response rate, we were unable to explore associations with gender, age, health status, geography, ethnicity, and prior clinical trial participation.

Conclusion

Our findings indicate an openness in Canada to participating in trials that decentralize or hybridize some aspects. These trials are perceived to provide benefits to participants and ways to increase equity and accessibility for participants.
Epidemiological aspects of individuals with mental disorders in the referral system: the experience of a Community Mental Health Center in the northeast of Iran
Authors: Talebi Mahdi , Niroumand Shabnam , Gholami Mobin , Samarghandi Azadeh , Shaygani Fatemeh , Radfar Mahdi , Nemati Ahmad
Published: June 2024

Background

Community Mental Health Centers (CMHCs) offer affordable mental health services in a less stigmatized environment, in a domiciliary setting. This study aimed to shed light on the epidemiological factors of patients attending CMHCs of Mashhad, their referral status, and treatment.

Methods

This study was conducted over the medical records of patients seen by psychiatrists between January 2014 and December 2021 in Mashhad's CMHC, the northeast of Iran. A detailed questionnaire was used to extract data from medical records about the epidemiological characteristics, diagnosed mental illnesses, referral status, and how often they visited the psychiatrist. The association between epidemiological findings and patient referral (referral system or self-referral) as well as the association between epidemiological findings and the number of psychiatric revisits were examined using the Chi-square test.

Results

Out of 662 patients, 472 (71%) were female and 190 (29%) were male, with an average age of 29 years. Among the 475 adult patients, 367 (77.3%) were married, with the majority being homemakers (56.4%). Major Depression Disorder (MDD) (32%) and Generalized Anxiety Disorder (GAD) (18.3%) were the most prevalent mental health conditions among patients. The majority of patients (74.9%) were referred to the CMHC of Mashhad from Primary Healthcare centers (PHCs) and psychiatric hospitals. Furthermore, female gender and patients with lower level of education were associated with more referral through from referral system. Of note, 431 patients (65.1%) did not return for a second visit, the ratio of treatment dropout was higher for patients with lower education levels.

Conclusions

Referral system should be more practical in Iran to enhance health services in CMHCs. It is recommended that PHCs undergo certain modifications to enhance the referral process for patients with mental health conditions, focusing on common mental disorders and individuals with low socioeconomic level.
Defining urban network resilience: a review
Authors: Jie Ren , Wentao Yan , Yuting Huang , Zihao Li
Published: June 2024

As concerns over the security of intercity connections intensify, the concept of urban network resilience has increasingly captured the attention of researchers in related fields. This study aimed to clarify the varying interpretations of urban network resilience among scholars and to identify the advancements and potential gaps in existing literature. The results indicated that differences in perceptions of urban networks have led scholars to define urban network resilience from two distinct perspectives. This divergence influenced the focal points of research, as well as the methodologies, structural measurement indicators, and optimization strategies employed in these studies. We argued for the need to further explore the concept of urban network resilience by considering the nuances of different urban networks, refining methodologies for the identification, description, and measurement of resilience, and recognizing the interconnections among various types and scales of urban networks. This review can provide scholars and policymakers with comprehensive insights into urban resilience, thereby assisting them in making more informed and effective decisions.
Bring Judgment Day
Authors: Bernard Sheila Curran
Published: June 2024

Known worldwide as Lead Belly, Huddie Ledbetter (1889–1949) is an American icon whose influence on modern music was tremendous – as was, according to legend, the temper that landed him in two of the South's most brutal prisons, while his immense talent twice won him pardons. But, as this deeply researched book shows, these stories were shaped by the white folklorists who 'discovered' Lead Belly and, along with reporters, recording executives, and radio and film producers, introduced him to audiences beyond the South. Through a revelatory examination of arrest, trial, and prison records; sharecropping reports; oral histories; newspaper articles; and more, author Sheila Curran Bernard replaces myth with fact, offering a stunning indictment of systemic racism in the Jim Crow era of the United States and the power of narrative to erase and distort the past.
Anthropogenically Driven Changes in the Carbon to Phosphorus Ratio of Marine Dissolved Organic Matter
Authors: Sreeush Mohanan Geethalekshmi , Kwon Eun Young , Lee Sun‐Seon , Nellikkattil Arjun Babu
Published: June 2024

Marine dissolved organic matter (DOM) cycles play a pivotal role in sustaining marine ecosystems and regulating the ocean's carbon sequestration from the atmosphere. However, the response of DOM cycles, including dissolved organic carbon (DOC) and dissolved organic phosphorus (DOP), to future climate change remains highly uncertain. Using the Community Earth System Model version 2 large ensemble simulations, we find that the C:P ratios in DOM are projected to increase by up to two‐fold in oligotrophic gyres by 2100. Increased upper ocean stratification reduces surface phosphate availability, thereby elevating phytoplankton C:P ratios and enhancing phytoplankton utilization of DOP, both acting to deprive DOM of P. Moreover, ocean stratification has a direct effect on exporting less DOC to the subsurface while accumulating more DOC at the sea surface. As a result of the strong sensitivity to ocean surface warming, the anthropogenically driven trends in upper ocean DOM concentration and its C:P ratios are estimated to emerge earlier from the simulated natural variability than upper ocean phosphate concentrations and net primary production—two key biogeochemical variables that are frequently monitored. This study suggests that changes in the C:P ratios of DOM could serve as a sensitive fingerprint of anthropogenic ocean warming, potentially exerting broad impacts on marine microbes. Our estimated 4% reduction in the globally integrated DOC export below 100 m is comparable to a 2% reduction in particulate organic carbon (POC) export by 2100, implying that global warming is likely to weaken the biological carbon pump through both DOC and POC.
Alaskan Glacial Dust Is an Important Iron Source to Surface Waters of the Gulf of Alaska
Authors: Crusius John , Lao Carsten A. , Holmes Thomas M. , Murray James W.
Published: June 2024

This work evaluates glacial dust as a source of sediment, and associated iron (Fe), to the Fe‐limited Gulf of Alaska (GoA). A reanalysis of GoA sediment data, using rare earth elements and thorium as provenance tracers, suggests a flux to the ocean surface of Copper River (AK) glacial dust, and associated Fe, that is comparable to the flux of dust from Asia, at least 1,000 km from the narrow mountain valley glacial dust source area. This work suggests dust from Asia may not be the largest source of Fe to the GoA. Dust models fail to accurately simulate this glacial dust transport because their coarse resolution underestimates wind speeds, and the dust flux. This work suggests that glacial dust fluxes may have been important in the geologic past (e.g., the last glacial maximum) from locations where there was more extensive coverage by glaciers than at present.
A Study of Ionospheric Heavy Ions in the Terrestrial Magnetotail Using ARTEMIS
Authors: Barani Mohammad , Poppe Andrew R. , Fillingim Matt O. , McFadden J. P. , Halekas J. S. , Sibeck David G.
Published: June 2024

Ionospheric heavy ions in the distant tail of the Earth's magnetosphere at lunar distances are observed using the ARTEMIS mission. These heavy ions are originally produced in the terrestrial ionosphere. Using the ElectroStatic Analyzers (ESA) onboard the two probes orbiting the Moon, these heavy ions are observed as cold populations with distinct energies higher than the baseline energy of protons, with the energy‐per‐charge values for the heavy populations highly correlated with the proton energies. We conducted a full solar cycle survey of these heavy ion observations, including the flux, location, and drift energy, as well as the correlations with the solar wind and geomagnetic indices. The likelihood of finding these heavy ions in the preferred regions of observation called “loaded” quadrants of the terrestrial magnetotail is ∼90%, regardless of the z orientation of the IMF. We characterize the ratio of the heavy ion energy to the proton energy, as well as the velocity ratio of these two populations, for events from 2010 to mid‐2023. This study shows that the “common velocity” assumption for the proton and heavy ion particles, as suggested in previous work through the velocity filter effect, is not necessarily valid in this case. Challenges in the identification of the mass of the heavy ions due to the ESA's lack of ion composition discrimination are addressed. It is proposed that at the lunar distances the heavy ion population mainly consists of atomic oxygen ions (O+) with velocities ∼25% more than the velocity of the co‐located proton population.
Full Dispersion‐Spectrum Inversion of Surface Waves
Authors: Zhang Zhendong , Alkhalifah Tariq , Liu Yike
Published: June 2024

Nowadays, the most successful applications of full‐waveform inversion (FWI) involve marine seismic data under acoustic approximations. Elastic FWI of land seismic data is still challenging in theory and practice. Here, we propose a full dispersion spectrum inversion method and apply it to seismic data acquired in West Antarctica. Inspired by the conventional surface wave dispersion curve inversion method, we propose to invert the surface wave dispersion spectrum instead of the complicated waveforms. We compare the frequency‐velocity, frequency‐slowness, and frequency‐wavenumber spectra in terms of their ability to resolve dispersion modes and the feasibility of their adjoint updates and conclude that the frequency‐slowness spectrum is the best for our inversion objectives. We test four objective functions, subtraction, zero‐lag crosscorrelation, optimal transport, and the local‐crosscorrelation to quantify the spectrum mismatch and provide the corresponding adjoint source. We then theoretically analyze the convexity of the proposed objective functions and examine their convergence behavior using numerical examples. We also compare the proposed method with the classic FWI method and the traditional surface wave dispersion curve inversion method and discuss the strengths and weaknesses of each method. This technique is employed to evaluate the shallow velocity structures beneath a seismic array stationed in West Antarctica. Our proposed inversion scheme is also useful for more general applications such as imaging the shallow subsurface of the critical zones, like geothermal reservoirs, and CO2 storage sites.
Frictional Properties and Healing Behavior of Tectonic Mélanges: Implications for the Evolution of Subduction Fault Zones
Authors: Chen T.‐W. , Affinito R. , Marone C. , Fisher D. , Smye A. , Hashimoto Y.
Published: June 2024

The frictional velocity dependence and healing behavior of subduction fault zones play key roles in the nucleation of stick‐slip instabilities at convergent margins. Diagenetic to low‐grade metamorphic processes such as pressure solution are proposed to be responsible for the change in frictional properties of fault materials along plate interfaces; pressure solution also likely contributes to the acceleration of healing according to previous studies. Here, we report friction studies for temperatures of 20–100°C and normal stresses from 20 to 125 MPa on samples collected from ancient subduction fault zones, the Lower Mugi and Makimine mélanges of the Cretaceous Shimanto belt. The two mélanges correspond to the updip and downdip limits of the seismogenic zone and include deformation features that indicate lower and higher degrees of pressure solution. Our data show that the Lower Mugi mélange exhibits velocity‐weakening to velocity‐neutral frictional behavior under low normal stress and that the Makimine mélange sample shows velocity‐strengthening behavior under high normal stress. We suggest that mineralogical changes due to diagenesis and metamorphism influence fault slip behavior. We measure frictional healing in slide‐hold‐slide experiments for the Lower Mugi mélange sample and document the role of pressure solution in fault healing. Our results show that frictional healing increases at higher temperatures. The microstructures related to pressure solution found in the post‐experimental gouges support the idea that the enhanced healing is related to pressure solution.
Mesoscale Eddies Influence Coral Reef Environments in the Northwest Gulf of Mexico
Authors: McWhorter J. K. , Roman‐Stork H. L. , Le Hénaff M. , Frenzel H. , Johnston M. A. , Cornec M. , Osborne E.
Published: June 2024

Coral reefs globally are experiencing more frequent and severe warming events due to anthropogenic driven climate change. Subtropical reefs experience more seasonal variability than lower latitude reefs making them typically more resilient to climate change. With relatively stable coral cover in comparison to other global coral reefs, Flower Garden Banks National Marine Sanctuary (FGBNMS) in the Gulf of Mexico is a series of 17 reefs and banks located on the continental shelf‐edge containing a variety of shallow (0–30 m) and mesophotic (30–150 m) coral reef habitats. Here, we use satellite data products to associate open ocean Argo float profiles with eddy features over FGBNMS to study the shelf‐edge reef environment spanning nearly two decades (2003–2022). Satellite data show that FGBNMS is frequently influenced (∼15 days/month) by mesoscale eddies. The upper water column variability (0–25 m) is most influenced by the seasonal mixed layer despite eddy interaction. Subsurface seasonal ranges of temperature and salinity are enhanced or suppressed depending on the influence of eddies in relation to the mixed layer depth. Within the mesophotic zone (0–150 m), the largest range of thermal variability between anticyclonic and cyclonic eddies is between 50 and 150 m upwards of 5°C. However, these observed dynamics will likely change as a result of eddy variability associated with projected warming and Loop Current weakening, leading to increased thermal stress in the future.
The Complexity of Moisture Sources Affects the Altitude Effect of Stable Isotopes of Precipitation in Inland Mountainous Regions
Authors: Chen Longhu , Zhu Guofeng , Lin Xinrui , Li Rui , Lu Siyu , Jiao Yinying , Qiu Dongdong , Meng Gaojia , Wang Qinqin
Published: June 2024

From a global perspective, the stable isotope altitude effect is crucial for understanding climate information. However, the intensity of this effect can be influenced by the source of moisture, particularly in inland mountainous regions where the moisture sources are complex. Different combinations of moisture sources might affect the altitude effect. Focusing on the upper Shiyang River in the northern part of the Qilian Mountains in China, this study calculated the proportion of recycled moisture in precipitation and utilized the HYSPLIT model to determine the source of advective moisture. It explored the characteristics and mechanisms by which moisture sources affect the spatiotemporal variations in precipitation isotope effects within the study area. The findings indicated that: (a) The altitude effect follows a seasonal pattern: winter < autumn < spring < summer, with a reverse effect in winter. (b) As the contribution of recycled moisture to precipitation increases, the altitude effect of stable isotopes weakens, primarily due to the disruptive influence of recycled moisture on this effect. (c) The altitude effect of stable isotopes in precipitation is determined by the direction of the moisture source and its attributes. When the primary source of advective moisture runs perpendicular to the mountain range and the moisture migration speed is slow, the altitude effect is pronounced. Thus, although temperature directly causes the altitude effect, water vapor sources significantly influence it in inland mountainous regions.
Pore‐Scale Modeling of Reactive Transport with Coupled Mineral Dissolution and Precipitation
Authors: Wang Ziyan , Hu Mengsu , Steefel Carl
Published: June 2024

We present a new pore‐scale model for multicomponent advective‐diffusive transport with coupled mineral dissolution and precipitation. Both dissolution and precipitation are captured simultaneously by introducing a phase transformation vector field representing the direction and magnitude of the overall phase change. An effective viscosity model is adopted in simulating fluid flow during mineral dissolution‐precipitation that can accurately capture the velocity field without introducing any empirical parameters. The proposed approach is validated against analytical solutions and interface tracking simulations in simplified structures. After validation, the proposed approach is employed in modeling realistic rocks where mineral dissolution and precipitation are dominant at different locations. We have identified three regimes for mineral dissolution‐precipitation coupling: (a) compact dissolution‐precipitation where dissolution is dominant near the inlet and precipitation is dominant near the outlet, (b) wormhole dissolution with clustered precipitation where dissolution generates wormholes in the main flow paths and precipitation clogs the secondary flow paths, and (c) dissolution dominant where all solid grains are gradually dissolved. In the three regimes, the proposed approach provides reliable porosity‐permeability relationships that cannot be described well by traditional macroscale models. We find that the permeability can increase while the overall porosity decreases when the main flow paths are expanded by dissolution and adjacent pore spaces are clogged by precipitation.
Tidal Control of Equatorial Vertical E × B Drift Under Solar Minimum Conditions
Authors: Liu H.‐L. , Maute A.
Published: June 2024

Observations show that equatorial ionospheric vertical drifts during solar minimum differ from the climatology between late afternoon and midnight. By analyzing WACCM‐X simulations, which reproduce this solar cycle dependence, we show that the interplay of the dominant migrating tides, their propagating and in situ forced components, and their solar cycle dependence impact the F‐region wind dynamo. In particular, the amplitude and phase of the propagating migrating semidiurnal tide (SW2) in the F‐region plays a key role. Under solar minimum conditions, the SW2 tide propagate to and beyond the F‐region in the winter hemisphere, and consequently its zonal wind amplitude in the F‐region is much stronger than that under solar maximum conditions. Furthermore, its phase shift leads to a strong eastward wind perturbation near local midnight. This in turn drives a F‐region dynamo with an equatorial upward drift between 18 and 1 hr local times.
Impact of the Polar Vortex on Sub‐Seasonal O/N2 Variability in the Lower Thermosphere Using GOLD and WACCM‐X
Authors: Martinez Benjamin C. , Lu Xian , Pedatella Nicholas M. , Wu Haonan , Oberheide Jens
Published: June 2024

We provide observational evidence that the stability of the stratospheric Polar vortex (PV) is a significant driver of sub‐seasonal variability in the thermosphere during geomagnetically quiet times when the PV is anomalously strong or weak. We find strong positive correlations between the Northern Annular Mode (NAM) index and subseasonal (10–90 days) Global Observations of the Limb and Disk (GOLD) O/N2 perturbations at low to mid‐northern latitudes, with a largest value of +0.55 at ∼30.0°N when anomalously strong or weak (NAM >2.5 or < −2.1) vortex times are considered. Strong agreement for O/N2 variability and O/N2‐NAM correlations is found between GOLD observations and the Whole Atmosphere Community Climate Model with thermosphere‐ionosphere eXtension (WACCM‐X) simulations, which is then used to delineate the global distribution of O/N2‐NAM correlations. We find negative correlations between subseasonal variability in WACCM‐X O/N2 and NAM at high northern and southern latitudes (as large as −0.54 at ∼60.0°S during anomalous vortex times). These correlations suggest that PV driven upwelling at low latitudes is accompanied by corresponding downwelling at high latitudes in the lower thermosphere (∼80–120 km), which is confirmed using calculations of residual mean meridional circulation from WACCM‐X.
Density Stratification and Buoyancy Evolution in Pyroclastic Density Currents
Authors: O’Donnell Sean B. , Johnson Blair A. , Breard Eric C. P. , Buttles James L. , Gardner James E. , Mohrig David , Dufek Josef
Published: June 2024

Pyroclastic density currents (PDCs) are density‐stratified along their vertical axis, with the near‐bed portion being denser than the upper portion, resulting from particle settling and ambient air entrainment at current margins. Whereas vertical density stratification likely influences mixing, sedimentation, and buoyancy of PDCs, many depth‐averaged models of PDC dynamics assume currents are well‐mixed. We investigated this discrepancy by performing sub‐aqueous laboratory experiments and conducted complementary numerical simulations to interrogate current dynamics at finer scales. Currents with small temperature difference with the ambient fluid become density‐stratified during propagation. The dynamics of such currents resemble two‐phase flows, in which particles move freely and particle concentration becomes stratified, but fluid density remains constant. Currents with large temperature difference with the ambient fluid, however, do not develop density stratification during propagation, due to current dynamics becoming dominated by the fluid phase and the lessening importance of particles. Currents that develop density stratification do not lift off from the bed within the domain of the setup, whereas poorly stratified currents do lift off, forming a rising plume. Strong density stratification within currents inhibits turbulence production, preventing entrained ambient fluid on current edges from mixing into current interiors. Poorly stratified currents are highly turbulent, have vigorous internal mixing, thereby achieving lift‐off. The strongly stratified currents are analogous to PDCs that result from eruption column collapse, maintaining fast velocity, low internal mixing, and high temperature over long distances. The poorly stratified currents are analogous to dilute ash‐cloud surges that develop atop basal avalanches, having short runout distances.
Automatic Estimation of Daily Volcanic Sulfur Dioxide Gas Flux From TROPOMI Satellite Observations: Application to Etna and Piton de la Fournaise
Authors: Grandin Raphaël , Boichu Marie , Mathurin Théo , Pascal Nicolas
Published: June 2024

Understanding the dynamics of sulfur dioxide (SO2) degassing is of primary importance for tracking temporal variations in volcanic activity. Here we introduce the novel “disk method,” which aims at estimating the daily volcanic SO2 mass flux from satellite images (such as those provided by Sentinel‐5P/TROPOspheric Monitoring Instrument [TROPOMI]). The method calculates a “proto‐flux” using a regression, as a function of distance, of SO2 mass integrated in a series of nested circular domains centered on a volcano. After regression, a single multiplication by plume speed suffices to deduce the SO2 mass flux, without requiring a subsequent regression. This way, a range of plume speed and plume altitude scenarios can be easily explored. Noise level in the image is simultaneously evaluated by the regression, which allows for estimating posterior uncertainties on SO2 flux and improving the level of detection for weak sources in noisy environments. A statistical test is also introduced to automatically detect occurrences of volcanic degassing, lowering the risk of false positives. Application to multi‐year time‐series at Etna (2021) and Piton de la Fournaise (2021–2023) demonstrates (a) a reliable quantification of SO2 emissions across a broad range of degassing styles (from passive degassing to effusive or paroxysmal events), and (b) a reasonable day‐to‐day correlation between SO2 flux and seismic energy. The method is distributed as an open‐source software, and is implemented in an interactive web application within the “Volcano Space Observatory Portal,” facilitating near‐real‐time exploitation of the TROPOMI archive for both volcano monitoring and assessment of volcanic atmospheric hazards.
CCL11 released by GSDMD-mediated macrophage pyroptosis regulates angiogenesis after hindlimb ischemia
Authors: Wang Yiwen , Gao Yang , Shi Huairui , Gao Rifeng , Yang Ji’e , Qu Ya’nan , Hu Shiyu , Zhang Jian , Wang Jingpu , Cao Jiatian , Zhang Feng , Ge Junbo
Published: June 2024

Peripheral vascular disease (PVD) is an emerging public health burden with a high rate of disability and mortality. Gasdermin D (GSDMD) has been reported to exert pyroptosis and play a critical role in the pathophysiology of many cardiovascular diseases. We ought to determine the role of GSDMD in the regulation of perfusion recovery after hindlimb ischemia (HLI). Our study revealed that GSDMD-mediated pyroptosis occurred in HLI. GSDMD deletion aggravated perfusion recovery and angiogenesis in vitro and in vivo. However, how GSDMD regulates angiogenesis after ischemic injury remains unclear. We then found that GSDMD-mediated pyroptosis exerted the angiogenic capacity in macrophages rather than endothelial cells after HLI. GSDMD deletion led to a lower level of CCL11 in mice serum. GSDMD knockdown in macrophages downregulated the expression and decreased the releasing level of CCL11. Furthermore, recombinant CCL11 improved endothelial functions and angiogenesis, which was attenuated by CCL11 antibody. Taken together, these results demonstrate that GSDMD promotes angiogenesis by releasing CCL11, thereby improving blood flow perfusion recovery after hindlimb ischemic injury. Therefore, CCL11 may be a novel target for prevention and treatment of vascular ischemic diseases.
Science and applications of 2.5D materials: development, opportunities and challenges
Authors: Ago Hiroki , Solís-Fernández Pablo
Published: June 2024

Research on two-dimensional (2D) materials has made tremendous progress reflecting their unique properties and promising applications. In this perspective, we review the novel concept of “2.5-dimensional (2.5D) materials”, which represent new opportunities to extend the field of materials science beyond 2D materials. This concept consists of controlling van der Waals interactions and using interlayer nanospaces to synthesize new materials and explore their intriguing properties. It also includes combination with other dimensional materials, the fabrication of three-dimensional (3D) architectures of 2D materials, and practical applications in our 3D everyday life. We discuss recent research based on this concept and provide future perspectives.