Hasil untuk "Metropolitan areas"

Teije Kuijper

We construct a Brownian motion on complex partial flag manifolds with blocks of equal size as a matrix-valued diffusion from a Brownian motion on the unitary group. This construction leads to an explicit expression for the characteristic function of the joint distribution of the stochastic areas on these manifolds. The limit law of these stochastic areas is shown to be a multivariate Cauchy distribution with independent and identically distributed entries. By relating the area functionals on flag manifolds to the winding functional on the complex Stiefel manifold, we establish new results about simultaneous Brownian windings on the complex Stiefel manifold. To establish these results, this work introduces a new family of diffusions, which generalise both the Jacobi processes on the simplex and the Hermitian Jacobi processes.

Muhammad Saad, MBBS, Reyan Hussain Shaikh, MBBS, Muhammad Umer Sohail, MBBS et al.

Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia, whereas cancer remains the second leading cause of death in the United States. Both conditions share several risk factors and may compound mortality risk. However, national trends in AF and cancer-related mortality remain underexplored. Objective: To assess trends in mortality related to AF and cancer among US adults from 1999 to 2019, using demographic and geographic stratifications. Methods: Data were obtained from the CDC WONDER Multiple Cause of Death data set. We identified individuals aged 25 years and older with AF (I48) and cancer (C00-C97) as an underlying or contributing cause of death. Age-adjusted mortality rates (AAMRs) per 100,000 population, average annual percentage change, and annual percentage change were calculated. Results: The AAMR for cancer and AF-related deaths increased from 4.95 (95% confidence interval [CI]: 4.84, 5.05) in 1999 to 10.01 (95% CI: 9.88, 10.13) in 2019 (average annual percentage change: 3.49 [95% CI: 3.39, 3.60]). Males had higher AAMRs than females (10.24 vs 5.13). Non-Hispanic Whites had the highest AAMRs (7.89), followed by non-Hispanic Blacks (4.53) and Hispanics (3.11). The Western region had the highest AAMR, and nonmetropolitan areas exhibited greater mortality rates than metropolitan areas. Individuals with lung cancer exhibited the highest AAMRs (1.65), followed by gastrointestinal cancer (1.52) and hematologic cancer (1.00). The lowest AAMRs were observed in prostate cancer (0.90) and breast cancer (0.65). Conclusion: Mortality from cancer and AF has increased over time, with significant disparities across sex, race, and geography. Targeted interventions are required to mitigate these disparities.

Jacob Daniel, Malcolm DeCamp, MD, Jennifer Romano, MD et al.

Objective: The makeup of the thoracic surgical workforce can influence policy, training, and certification, but it is not well defined. Using data from the American Board of Thoracic Surgery, this study explored practice-based demographics concerning geography, gender, age, subspecialty, and university affiliation. Methods: American Board of Thoracic Surgery Diplomates taking the 10-year Maintenance of Certification examination opted for the cardiac, general thoracic, cardiothoracic, or congenital modular exam. Using module selection as a surrogate for the examinee's predominant clinical practice, we explored the relationship regarding type of practice, geography (metropolitan vs other), gender, age, and university affiliation. Results: A total of 2273 American Board of Thoracic Surgery Diplomates took the Maintenance of Certification exam from 2018 to 2024. Adult cardiac surgery was the predominant subspecialty (46%), followed by cardiothoracic (24%), general thoracic (22%), and congenital surgery (8%). Significant gender disparity persisted, with women constituting 7% of certified Diplomates and 5% of adult cardiac surgeons. Mean ages ranged from 58.0 years (general thoracic) to 63.3 years (cardiothoracic), with younger surgeons trending toward specialized practices (cardiac P = .01, congenital P = .04). Most surgeons practiced in metropolitan areas (80%), particularly congenital surgeons (96%). Surgeons practicing in university (47%) and nonuniversity settings (53%) were nearly evenly distributed. Conclusions: Thoracic surgery is increasingly subspecializing, with younger surgeons choosing cardiac, general thoracic, or congenital surgery modular Maintenance of Certification exams. The percentage of female Diplomates remains low. Maintenance of Certification exam-eligible diplomates constitute a predominantly older workforce with noticeable urbanization. Understanding our workforce provides important insight for American Board of Thoracic Surgery certification, the development of training paradigms, and anticipating workforce needs.

Larissa Yumi ITO, Leticia Maíra WAMBIER, Ana Cláudia Rodrigues CHIBINSKI et al.

Abstract This study aimed to analyze the factors associated with the perception among Brazilian dentists of the preventive or therapeutic use of sealants on permanent molars. A cross-sectional web-based survey was conducted with Brazilian dentists between July and October 2021 to examine their use of social media and gather data regarding sealant-related practices. A structured questionnaire was developed and applied to collect information on participants’ professional profiles, clinical indications, materials, techniques, and perceptions of pit and fissure sealants. The study outcomes were the positive perception of sealant use as: (a) a preventive measure, or (b) a therapeutic approach to carious lesions. Responses were dichotomized into positive perception (“strongly agree” or “agree”) and negative perception (“neither agree nor disagree,” “disagree” or “strongly disagree”). Independent variables included sociodemographic, educational, professional, and technical characteristics. Multiple logistic regression models were used to analyze associations (p < 0.05). A total of 2,394 dentists participated in the study, 82.5% of whom had a positive perception of sealants for prevention, and 83.1%, for therapeutic purposes. A greater likelihood of positive perception of preventive sealant use was observed among educators, those employed in public health services, dentists who “always” performed sealant application, and those who used resin sealant, glass ionomer cement, or flowable resin. Conversely, professionals working in capital cities had a lower likelihood of a positive perception. Professionals from cities with populations exceeding 500,000 inhabitants, interior areas, or metropolitan regions were less likely to have a positive perception of therapeutic sealant use. However, those who used resin sealants, glass ionomer cement, or flowable resin were more likely to perceive sealants positively. In conclusion, the positive perception of sealant use for prevention was associated with educational, professional, and technical factors, whereas the positive perception of therapeutic use was associated with professional and technical factors.

Sophia Shen, Xinyi Wang, Nicholas Caros et al.

The overall impact of working from home (WFH) on transportation emissions remains a complex issue, with significant implications for policymaking. This study matches socioeconomic information from American Community Survey (ACS) to the global carbon emissions dataset for selected Metropolitan Statistical Areas (MSAs) in the US. We analyze the impact of WFH on transportation emissions before and during the COVID-19 pandemic. Employing cross-sectional multiple regression models and Blinder-Oaxaca decomposition, we examine how WFH, commuting mode, and car ownership influence transportation emissions across 141 MSAs in the United States. We find that the prevalence of WFH in 2021 is associated with lower transportation emissions, whereas WFH in 2019 did not significantly impact transportation emissions. After controlling for public transportation usage and car ownership, we find that a 1% increase in WFH corresponds to a 0.17 kg or 1.8% reduction of daily average transportation emissions per capita. The Blinder-Oaxaca decomposition shows that WFH is the main driver in reducing transportation emissions per capita during the pandemic. Our results show that the reductive influence of public transportation on transportation emissions has declined, while the impact of car ownership on increasing transportation emissions has risen. This study underscores the need for a nuanced, data-driven approach in crafting WFH policies to mitigate transportation emissions effectively. This study contributes to the policy debate by advocating for WFH as a strategy to reduce transportation emissions. Concurrently, policymakers can mitigate its unintended consequences by promoting public transportation and encouraging the adoption of environmentally friendly commute modes.

Qiujin Shen, Xiaowen Gong, Wei Zhang et al.

BackgroundRecently, we developed and tested an autonomous artificial intelligence (AI) agent for prescribing a drug to prevent severe acute graft-versus-host disease in patients receiving human leukocyte antigen haplotype–mismatched hematopoietic cell transplants in a prospective clinical trial. Our experience in this proof-of-concept study suggests that physicians and patients can be receptive to autonomous AI prescription. However, the generalizability of our conclusion requires testing in additional clinical settings. Before broadening the scope of study of AI-driven drug prescriptions, it is important to quantify the factors that influence a physician’s receptiveness to AI prescription. ObjectiveWe aim to systematically interrogate physicians’ receptiveness to AI prescription in China. MethodsWe have designed a research protocol to survey a diverse range of factors that may affect physicians’ receptiveness to AI prescription systems, including the physicians’ personal attributes and their perceptions of the importance of various technological, institutional, and governmental attributes. The survey will be conducted in 2 phases. In phase 1, the survey will be limited to the Tianjin metropolitan area, enlisting >250 physicians from approximately 2 tier-1, 3 tier-2, and 3 tier-3 hospitals. In phase 2, we will survey metropolitan areas in ≥10 additional province-level administrative divisions, enlisting >1250 additional physicians from >15 tier-1, >15 tier-2, and >15 tier-3 hospitals. We hypothesize that physicians can be broadly classified into distinct psychological profile types, and furthermore, that these types are plausibly mediated by the locales where the physicians are employed and the physicians’ demographics, educational and job experience, clinical subspecialties, and previous knowledge of and experience with AI. Clustering methods, including t-distributed stochastic neighbor embedding and hierarchical clustering, will be performed on respondent data to identify the distinct psychological profile types of the physicians. Multiple-variable regression and mediation analyses will be conducted to identify potential underlying mechanisms mediating physicians’ receptiveness to AI prescription. ResultsAt the time of submission of the manuscript, no subjects have been recruited. The survey study was approved by the institutional ethics committee and funded in May 2025, and we started recruiting respondents in May 2025. We plan to complete phase 1 by September 30, 2025, and phase 2 by November 30, 2025. Anonymized survey results and their analyses are expected to be published in a peer-reviewed journal in fall 2026. ConclusionsWe anticipate that data and analytical insights generated from this study will assist policy makers and AI researchers in prioritizing a data-informed sequence of developing and promoting AI prescription tools in successive regions, disciplines, and clinical use cases and inform policy makers to match resource allocation with “AI readiness.” International Registered Report Identifier (IRRID)PRR1-10.2196/76009

Sarah Al-Shareeda, Sema F. Oktug, Yusuf Yaslan et al.

This paper investigates the potential of Digital Twins (DTs) to enhance network performance in densely populated urban areas, specifically focusing on vehicular networks. The study comprises two phases. In Phase I, we utilize traffic data and AI clustering to identify critical locations, particularly in crowded urban areas with high accident rates. In Phase II, we evaluate the advantages of twinning vehicular networks through three deployment scenarios: edge-based twin, cloud-based twin, and hybrid-based twin. Our analysis demonstrates that twinning significantly reduces network delays, with virtual twins outperforming physical networks. Virtual twins maintain low delays even with increased vehicle density, such as 15.05 seconds for 300 vehicles. Moreover, they exhibit faster computational speeds, with cloud-based twins being 1.7 times faster than edge twins in certain scenarios. These findings provide insights for efficient vehicular communication and underscore the potential of virtual twins in enhancing vehicular networks in crowded areas while emphasizing the importance of considering real-world factors when making deployment decisions.

Garth Warner

Here one will find a rigorous treatment of the simplest situation in Surface Area Theory, viz. the nonparametric case with domain the unit square in the plane. This is installment IV of a four part discussion of certain aspects of Real Analysis: Functions of a Single Variable, Curves and Length, Functions of Several Variables, and Surfaces and Area.

Naoki Tamura, Kazuyuki Shoji, Shin Katayama et al.

We publicly release OpenUAS, a dataset of area embeddings based on urban usage patterns, including embeddings for over 1.3 million 50-meter square meshes covering a total area of 3,300 square kilometers. This dataset is valuable for analyzing area functions in fields such as market analysis, urban planning, transportation infrastructure, and infection prediction. It captures the characteristics of each area in the city, such as office districts and residential areas, by employing an area embedding technique that utilizes location information typically obtained by GPS. Numerous area embedding techniques have been proposed, and while the public release of such embedding datasets is technically feasible, it has not been realized. One reason for this is that previous methods could not embed areas from different cities and periods into the same embedding space without sharing raw location data. We address this issue by developing an anchoring method that establishes anchors within a shared embedding space. We publicly release this anchor dataset along with area embedding datasets from several periods in eight major Japanese cities.

Yecheng Zhang, Tangqi Tu, Ying long

Due to rapid urbanization over the past 20 years, many newly developed areas have lagged in socio-economic maturity, creating an imbalance with older cities and leading to the rise of "ghost cities." However, due to the complexity of socio-economic factors, no global studies have measured this phenomenon. We propose a unified framework based on urban vitality theory and multi-source data, validated by various data sources. We derived 8841 natural cities globally with an area over 5 square kiloxmeters and divided each into new urban areas (developed after 2005) and old urban areas (developed before 2005). Urban vitality was gauged using the density of road networks, points of interest (POIs), and population density with 1 km resolution across morphological, functional, and social dimensions. By comparing urban vitality in new and old urban areas, we quantify the ghost cities index (GCI) globally using the theory of urban vitality for the first time. The results reveal that the vitality of new urban areas is 7.69% that of old ones. The top 5% (442) of cities were designated as ghost cities, a finding mirrored by news media and other research. This study sheds light on strategies for sustainable global urbanization, crucial for the United Nations' Sustainable Development Goals.

Ahmed Emam, Timo T. Stomberg, Ribana Roscher

Natural protected areas are vital for biodiversity, climate change mitigation, and supporting ecological processes. Despite their significance, comprehensive mapping is hindered by a lack of understanding of their characteristics and a missing land cover class definition. This paper aims to advance the explanation of the designating patterns forming protected and wild areas. To this end, we propose a novel framework that uses activation maximization and a generative adversarial model. With this, we aim to generate satellite images that, in combination with domain knowledge, are capable of offering complete and valid explanations for the spatial and spectral patterns that define the natural authenticity of these regions. Our proposed framework produces more precise attribution maps pinpointing the designating patterns forming the natural authenticity of protected areas. Our approach fosters our understanding of the ecological integrity of the protected natural areas and may contribute to future monitoring and preservation efforts.

Ya-Peng Lee, Tzai-Hung Wen

Abstract Identifying clusters or hotspots from disease maps is critical in research and practice. Hotspots have been shown to have a higher potential for transmission risk and may be the source of infections, making them a priority for controlling epidemics. However, the role of edge areas of hotspots in disease transmission remains unclear. This study aims to investigate the role of edge areas in disease transmission by examining whether disease incidence rate growth is higher in the edges of disease hotspots during outbreaks. Our data is based on the three most severe dengue epidemic years in Kaohsiung city, Taiwan, from 1998 to 2020. We employed conditional autoregressive (CAR) models and Bayesian areal Wombling methods to identify significant edge areas of hotspots based on the extent of risk difference between adjacent areas. The difference-in-difference (DID) estimator in spatial panel models measures the growth rate of risk by comparing the incidence rate between two groups (hotspots and edge areas) over two time periods. Our results show that in years characterized by exceptionally large-scale outbreaks, the edge areas of hotspots have a more significant increase in disease risk than hotspots, leading to a higher risk of disease transmission and potential disease foci. This finding explains the geographic diffusion mechanism of epidemics, a pattern mixed with expansion and relocation, indicating that the edge areas play an essential role. The study highlights the importance of considering edge areas of hotspots in disease transmission. Furthermore, it provides valuable insights for policymakers and health authorities in designing effective interventions to control large-scale disease outbreaks.

Songyang Zhang, Tianhang Yu, Jonathan Tivald et al.

Radio map describes network coverage and is a practically important tool for network planning in modern wireless systems. Generally, radio strength measurements are collected to construct fine-resolution radio maps for analysis. However, certain protected areas are not accessible for measurement due to physical constraints and security considerations, leading to blanked spaces on a radio map. Non-uniformly spaced measurement and uneven observation resolution make it more difficult for radio map estimation and spectrum planning in protected areas. This work explores the distribution of radio spectrum strengths and proposes an exemplar-based approach to reconstruct missing areas on a radio map. Instead of taking generic image processing approaches, we leverage radio propagation models to determine directions of region filling and develop two different schemes to estimate the missing radio signal power. Our test results based on high-fidelity simulation demonstrate efficacy of the proposed methods for radio map reconstruction.

Bianca Dittrich, Athanasios Kogios

Although spin foams arose as quantizations of the length metric degrees of freedom, the quantum configuration space is rather based on areas as more fundamental variables. This is also highlighted by the semi-classical limit of four-dimensional spin foam models, which is described by the Area Regge action. Despite its central importance to spin foams the dynamics encoded by the Area Regge action is only poorly understood, in particular in the continuum limit. We perform here a systematic investigation of the dynamics defined by the Area Regge action on a regular centrally subdivided hypercubical lattice. This choice of lattice avoids many problems of the non-subdivided hypercubical lattice, for which the Area Regge action is singular. The regularity of the lattice allows to extract the continuum limit and its corrections, order by order in the lattice constant. We show that, contrary to widespread expectations which arose from the so-called flatness problem of spin foams, the continuum limit of the Area Regge action does describe to leading order the same graviton dynamics as general relativity. The next-to-leading order correction to the effective action for the length metric is of second order in the lattice constant, and is given by a quadratic term in the Weyl curvature tensor. This correction can be understood to originate from an underlying dynamics of area metrics. This suggests that the continuum limit of spin foam dynamics does lead to massless gravitons, and that the leading order quantum corrections can be understood to emerge from a generalization of the configuration space from length to area metrics.

Wesley dos Reis Bezerra, Cristiano Antônio de Souza, Carla Merkle Westphall et al.

The large volume of publications in any research area can make it difficult for researchers to track their research areas' trends, challenges, and characteristics. Bibliometrics solves this problem by bringing statistical tools to help the analysis of selected publications from an online database. Although there are different works in security, our study aims to fill the bibliometric gap in the authentication and threat model area. As a result, a description of the dataset obtained, an overview of some selected variables, and an analysis of the ten most cited articles in this selected dataset is presented, which brings together publications from the last 28 years in these areas combined.

Aeris El Asslouj, Harshvardhan Uppaluru, Hossein Rastgoftar

This paper studies the problem of fast and safe aerial payload transport by a single quadcopter in urban areas. The quadcopter payload system (QPS) is considered as a rigid body and modeled with a nonlinear dynamics. The urban area is modeled as an obstacle-laden environment with obstacle geometries obtained by incorporating realistic LIDAR data. Our approach for payload transport is decomposed into high-level motion planning and low-level trajectory control. For the low-level trajectory tracking, a feedback linearization control is applied to stably track the desired trajectory of the quadcopter. For high-level motion planning, we integrate A* search and polynomial planning to define a safe trajectory for the quadcopter assuring collision avoidance, boundedness of the quadcopter rotor speeds and tracking error, and fast arrival to a target destination from an arbitrary initial location.

Virginia Mckay, Mia Vogel, Todd Combs et al.

Abstract Background Tobacco control program leaders and their partners, who often present evidence to policymakers, can increase the use of evidence in program and policy development. However, up-to-date evidence from the scientific community about what works is slow to reach leaders. We describe efforts to understand and utilize tobacco control leaders’ preferences for receiving evidence and report on resulting dissemination strategies, translational products, and outcomes. Methods This work is part of the Advancing Science and Practice in the Retail Environment (ASPiRE) Center, an interdisciplinary research center focused on understanding and evaluating tobacco retail policy. Participants were members of the ASPiRE Community Advisory Board (CAB), comprised of tobacco control leaders from 30 metropolitan areas representing all regions of the US plus nine representatives from leading national tobacco control organizations (N = 39). During meetings in February 2019 and October 2020, all CAB members were invited to participate in live polls consisting of six survey questions each. Questions addressed preferences for receiving scientific evidence and their anticipated use of ASPiRE translational products. Responses were analyzed descriptively and informed translational product development and communications with ASPiRE contact list members (N = 125). ASPiRE email and website interactions were tracked from March 2019 to May 2021 as a complementary indication of content use. Results Response rates for 2019 and 2020 CAB meetings were 66% (n = 26) and 59% (n = 23), respectively. CAB members indicated preferences for email communication (33%) and webinars (31%), communications once per month (46%), and short-format documents (28%). In response, the team developed translational short-format products including case studies, fact sheets, and research briefs. On average, 52% (SD = 14%) of recipients opened the newsletter and 17% (SD = 9%) clicked a link within the newsletter. Overall, 95% of responding CAB members found the products useful and all responding CAB members reported using them to communicate evidence to policymakers, staff, and coalition members. Conclusions Our successful dissemination approach to making evidence more accessible and useable for tobacco control leaders could be adapted by researchers working with community partners to assess and respond to stakeholders’ preferences for receiving evidence in other areas of health policy.

Wu-zhong Guo

The fixed area states are constructed by gravitational path integrals in previous studies.In this paper we show the dual of the fixed area states in conformal field theories (CFTs).These CFT states are constructed by using spectrum decomposition of reduced density matrix $ρ_A$ for a subsystem $A$. For 2 dimensional CFTs we directly construct the bulk metric, which is consistent with the expected geometry of the fixed area states. For arbitrary pure geometric state $|ψ\rangle$ in any dimension we also find the consistency by using the gravity dual of Rényi entropy. We also give the relation of parameters for the bulk and boundary state. The pure geometric state $|ψ\rangle$ can be expanded as superposition of the fixed area states. Motivated by this, we propose an area operator $\hat A^ψ$. The fixed area state is the eigenstate of $\hat A^ψ$, the associated eigenvalue is related to Rényi entropy of subsystem $A$ in this state. The Ryu-Takayanagi formula can be expressed as the expectation value $\langle ψ| {\hat A}^ψ|ψ\rangle$ divided by $4G$, where $G$ is the Newton constant. We also show the fluctuation of the area operator in the geometric state $|ψ\rangle$ is suppressed in the semiclassical limit $G\to0$.

Mohamad soleimani Meranjani, Ali Shamai, Taher Parizadi et al.

Objective:Neighborhood as a "spatial" and historical phenomenon has usually had two dimensions: explicit or implicit territory, and the other is a "special social group".Spatial matching of neighborhood and the local community, especially in metropolitan areas, was discussed in the urban literature. Explaining the process of this divergence and the impact of urbanism on it in the scale of Tehran metropolitan neighborhoods has been the main issue of this article. Methods: This research was of the survey-analytical type, and the method of data collection was documentary-field. The statistical population is Tehran's metropolitan neighborhoods that, based on a classification, five neighborhoods have been selected by purposive sampling. Quantitative and statistical methods including one-sample t-test, one-way ANOVA, Tukey post hoc test, and multivariate regression were used to analyze the data. Results:The results showed that despite the changes caused by modernity, it is still possible to distinguish a range of neighborhoods from the community's characteristics in the metropolis of Tehran. The level of neighborhood identity in Tehran's sample neighborhoods has been relatively high; however, this situation has not led to the formation and improvement of their residents' interactions and internal social solidarity. The results also showed that all indicators of urbanism as an independent variable had significant relationships and negative effects on the community's characteristics in the sample neighborhoods. Conclusion: However, the findings of this article indicate the existence of fields and capital of the community in the sample neighborhoods of Tehran; However, based on the basic idea of the research, it should be noted that promoting and strengthening the spatial matching of community and neighborhood is the basic condition for creating, improving and recreating existing neighborhoods within the framework of modern metropolitan discourse and urbanism of Tehran metropolitan scale.

Mina Saeidi, Sahar Nedae Tousi

In the age of globalization and competitiveness of urban centers, the creative class is considered as one of the main drivers of growth and development of metropolitan areas. In this regard, the recruitment and maintenance of this social group, by identifying and evaluating their spatial preferences, has been included in the agenda of spatial development planning of cities and metropolitan areas. Accordingly, the aim of the present study is to (1) explain the relationship between the creative class as driving forces and growth and development as an achievement and also (2) identify the various spatial preferences of creative classes of Tehran metropolis to allocate residential, leisure, activity and communication needs. The combined methodology (qualitative and quantitative) has been used in this article; In collecting information, the methods of documentary, statistical and social analysis were used in the form of interviews and questionnaires, and in the classification of creative groups, the scenario method was used. The high correlation between the share of creative manpower and the value-added output confirms this claim. Similarly, the analysis makes it possible to identify four distinct groups: naturalistic, urbanist, knowledge-based, and artistic, depending on the differences in the characteristics of the activity and the spatial preferences of the creative class. Creating and maintaining a creative class in the metropolis of Tehran requires identifying the differences, features, and preferential spatial preferences of each of these groups. Based on this, their spatial-activity preferences were identified and presented in the form of solutions.