Hasil untuk "America"

William F. Alterman

J. Dickinson, The American Ornithologists Union

D. Bell

Christian Sparta

W. Sturtevant

Funing Li, Talia Tamarin-Brodsky

Moist heatwaves and convective storms frequently co-occur, posing compound risks. Although historically concentrated in the tropics, these moist weather extremes are projected to intensify substantially towards the midlatitudes, with regions downstream of major highland terrains, including northeastern Asia and eastern North America, emerging as hotspots of future change. Yet their physical drivers remain uncertain. Here we show that the intensification of concurrent moist heat and convection extremes in the midlatitudes is tightly constrained by changes in low-level atmospheric inversions. Specifically, we find that amplified warming over western highlands is transported downstream by prevailing westerlies, strengthening low-level thermal inversions and raising the attainable maxima of moist heat and convection. Targeted model experiments confirm the critical role of orographically elevated heating in driving these extremes. Our results reveal a mechanistic pathway for compound extremes and highlight low-level inversions as a key factor for emerging midlatitude risks of moist heat and severe weather under climate change.

A. Bloom

J. Pindell, J. Dewey

A Permo-Triassic reconstruction of western Pangea (North America, South America, Africa) is proposed that is characterized by (1) definition of the North Atlantic fit by matching of marginal offsets (fracture zones) along the opposing margins, (2) a South Atlantic fit that is tighter than the BuIlard fit and that is achieved by treating Africa as two plates astride the Benue Trough and related structures during the Cretaceous, (3) complete closure of the Proto-Atlantic Ocean between North and South America, accomplished by placing the Yucatan block between the Ouachita Mountains and Venezuela, (4) a proposed Hercynian suture zone that separates zones of foreland thrusting from zones of arc-related magmatic activity; to the northwest of this suture lie the Chortis block and Mexico and most of North America, and to the southeast lie South America, the Yucatan Block, Florida and Africa, and (5) satisfaction of paleomagmatic data from North America, South America, and Africa. Beginning with the proposed reconstruction, the relative motion history of South America with respect of North America is defined by using the finite difference method. Within the framework provided by the proposed relative motion history, an evolutionary model for the development of the Gulf of Mexico and Caribbean region is outlined in a series of 13 plate boundary reconstructions at time intervals from the Jurassic to the present. The model includes (1) formation of the Gulf of Mexico by 140 Ma, (2) Pacific provenance of the Caribbean plate through the North America-South America gap during Cretaceous time, (3) Paleocene-Early Eocene back arc spreading origin for the Yucatan Basin, whereby Cuba is the frontal arc and the Nicaragua Rise-Jamaica-Southern Hispaniola is the remnant arc, and (4) 1200 km of post-Eocene cumulative offset along both the Northern and Southern Caribbean Plate Boundary Zones, allowing large-scale eastward migration of the Caribbean plate with respect to the North and South American Plates.

Frederick M. Azar

Kavindi Madduma Hewage, Carlos Munoz, Mehmet Ozdogan et al.

Lyme disease, caused by the bacterium Borrelia burgdorferi, is a significant public health concern in North America, with approximately 500,000 cases reported annually in the United States. The dissemination of B. burgdorferi from the initial tick bite site to various tissues is facilitated by surface adhesins that bind to extracellular matrix (ECM) proteins such as fibronectin (Fn). This study investigates the binding dynamics of B. burgdorferi surface proteins RevA, BBK32, BmpA, OspA, and OspC to Fn using atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS). Our results demonstrate that RevA and BBK32 form strong, stable bonds with Fn, highlighting their roles as key mediators of host-cell attachment. By quantifying the rupture forces and kinetic parameters of these interactions, we provide a deeper understanding of B. burgdorferi adhesion mechanics and offer insights into potential therapeutic strategies targeting early bacterial attachment.

Abdelaziz Benaddi, Abdelilah Lissaneddine

The opening of Marrakech to the world, its dual UNESCO listing, and the development of its tourism have transformed the old medina. Since the late 1980s, it has become a tourist destination marked by urban beautification and aesthetic-architectural improvement. The attraction of foreigners to old houses (dars, riads, and ancient palaces) plays a key role in the spread of tourism, offering an immersion into the socio-spatial universe of historically rich intramural neighborhoods.What are the underlying logics of the spread of tourism in the medina of Marrakech? And how has the appropriation of its houses by foreign residents redefined the relationship with space within its neighborhoods? In this article, we will first study the mechanisms of the spread of tourism and the proliferation of riad-guesthouses (RGHs) within the medina, highlighting their correlation with the way domestic space and ancestral neighborhoods are appropriated by and for visitors. Secondly, we will examine the transformation of the socio-spatial landscape of the medina since the 1990s and the new socio-economic modalities of the relationship with domestic space and old neighborhoods.

Wenjing Li, Yinji Jin, Xiang Li et al.

Abstract Background Persistent infection with high-risk human papillomavirus (HPV) types is a well-established risk factor for various malignancies, and timely vaccination of university students is a cost-effective strategy to reduce infection rates and the burden of HPV-associated consequences. Although many studies have examined HPV knowledge, vaccine acceptance, and uptake in university students, findings remain heterogeneous, and comprehensive quantitative synthesis is limited. This systematic review and meta-analysis aims to assess global estimates of university students’ knowledge of HPV and its vaccine, willingness to receive the vaccine, and actual vaccination behaviors. Methods The study was reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) 2020 Checklist. A systematic search was conducted in PubMed, Web of Science, China Biology Medicine disc, China National Knowledge Infrastructure and Wan Fang Database for studies published from January 2006 through August 2024. Studies with quality assessment scores > 5 and published in Chinese or English were included for data extraction. Pooled prevalence estimates and 95% confidence intervals (CI) were calculated using the Freeman-Tukey double arcsine transformation. The heterogeneity statistic I-squared and corresponding p value were also reported. Results A total of 56 studies covering 184,351 university students from four continents (Asia, Africa, Europe and North America) were included. Among students, 68.3% (95% CI 56.4%-79.0%) and 53.5% (95% CI 53.0%-54.1%) were aware of HPV and HPV vaccine, respectively, with significant gaps in knowledge about HPV symptoms, cervical cancer screening methods, and optimal vaccination timing. Pooled HPV vaccination willingness was 52.9% (95% CI 44.2%-61.6%), with higher willingness observed among females and medical students. Only 10.4% (95% CI 6.1%-15.8%) had received at least 1 dose of vaccination and 12.4% (95% CI 3.0%-26.9%) had completed the full three-dose schedule. Vaccination coverage among females was 8.6% (95% CI 3.7%–15.1%), and among medical students, 7.7% (95% CI 1.3%-18.4%). Conclusions This meta-analysis found that university students exhibit limited awareness of HPV and its vaccine, with about half willing to be vaccinated. Actual vaccination rates remain low and vary widely by gender, major, time of year, and geographic regions. These findings highlight the need for targeted intervention strategies, such as precision education and cross-sector collaboration, to effectively increase HPV vaccination coverage in this population.

Cristiano Fanelli, James Giroux, Patrick Moran et al.

The 2023 AI4EIC hackathon was the culmination of the third annual AI4EIC workshop at The Catholic University of America. This workshop brought together researchers from physics, data science and computer science to discuss the latest developments in Artificial Intelligence (AI) and Machine Learning (ML) for the Electron Ion Collider (EIC), including applications for detectors, accelerators, and experimental control. The hackathon, held on the final day of the workshop, involved using a chatbot powered by a Large Language Model, ChatGPT-3.5, to train a binary classifier neutrons and photons in simulated data from the \textsc{GlueX} Barrel Calorimeter. In total, six teams of up to four participants from all over the world took part in this intense educational and research event. This article highlights the hackathon challenge, the resources and methodology used, and the results and insights gained from analyzing physics data using the most cutting-edge tools in AI/ML.

J. Slik, J. Franklin, V. Arroyo‐Rodríguez et al.

Significance Identifying and explaining regional differences in tropical forest dynamics, structure, diversity, and composition are critical for anticipating region-specific responses to global environmental change. Floristic classifications are of fundamental importance for these efforts. Here we provide a global tropical forest classification that is explicitly based on community evolutionary similarity, resulting in identification of five major tropical forest regions and their relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. African and American forests are grouped, reflecting their former western Gondwanan connection, while Indo-Pacific forests range from eastern Africa and Madagascar to Australia and the Pacific. The connection between northern-hemisphere Asian and American forests is confirmed, while Dry forests are identified as a single tropical biome. Knowledge about the biogeographic affinities of the world’s tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world’s tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests.

J. Deetz

K. Bryc, A. Auton, M. Nelson et al.

Jose González-Abad, Jorge Baño-Medina, José Manuel Gutiérrez

Deep learning (DL) has emerged as a promising tool to downscale climate projections at regional-to-local scales from large-scale atmospheric fields following the perfect-prognosis (PP) approach. Given their complexity, it is crucial to properly evaluate these methods, especially when applied to changing climatic conditions where the ability to extrapolate/generalise is key. In this work, we intercompare several DL models extracted from the literature for the same challenging use-case (downscaling temperature in the CORDEX North America domain) and expand standard evaluation methods building on eXplainable artifical intelligence (XAI) techniques. We show how these techniques can be used to unravel the internal behaviour of these models, providing new evaluation dimensions and aiding in their diagnostic and design. These results show the usefulness of incorporating XAI techniques into statistical downscaling evaluation frameworks, especially when working with large regions and/or under climate change conditions.

Adejoke T. Odebade, Elhadj Benkhelifa

This study compares the National Cybersecurity Strategies (NCSSs) of publicly available documents of ten nations across Europe (United Kingdom, France, Lithuania, Estonia, Spain, and Norway), Asia-Pacific (Singapore and Australia), and the American region (the United States of America and Canada). The study observed that there is not a unified understanding of the term "Cybersecurity"; however, a common trajectory of the NCSSs shows that the fight against cybercrime is a joint effort among various stakeholders, hence the need for strong international cooperation. Using a comparative structure and an NCSS framework, the research finds similarities in protecting critical assets, commitment to research and development, and improved national and international collaboration. The study finds that the lack of a unified underlying cybersecurity framework leads to a disparity in the structure and contents of the strategies. The strengths and weaknesses of the NCSSs from the research can benefit countries planning to develop or update their cybersecurity strategies. The study gives recommendations that strategy developers can consider when developing an NCSS.

Bin Bai, Yuan-Qing Wang, Yuan-Qing Wang et al.

Artiodactyls diversified during the Eocene and Oligocene in North America and Europe after their first Holarctic appearance at the beginning of the Eocene. However, the relationships among early artiodactyls, European endemic forms, and later derived suiforms, tylopods, and ruminants remain unclear. Early artiodactyls are relatively rare in Asia compared to those known from North America and Europe; thus, investigation of Eocene artiodactyls from Asia is important to resolve these issues. Here we report two new genera and three new species of small early artiodactyls from middle Eocene deposits of the Erlian Basin, Inner Mongolia, China. The new materials represent a morphologically gradational series from Asian Land Mammal Ages Irdinmanhan to Sharamurunian, characterized by a trend towards bilophodonty in the lower molars. Morphologic and phylogenetic analyses suggest that these new taxa have a close relationship with the enigmatic European Tapirulus, which currently consists of five species that range from the middle Eocene to the early Oligocene. The close relationship between the Erlian specimens and Tapirulus suggests possible faunal exchanges between Europe and Asia during the middle Eocene, a view that has been supported by other mammalian groups across the two continents. The evolution of bilophodonty in Tapirulidae and Raoellidae is probably attributable to convergence.

Andrew R Kampfschulte, Rebecca K Miller

Community-wide wildfire mitigation can effectively protect homes from structure ignition. The Firewise USA program provides a framework for grassroots wildfire preparedness. Here, we examine the 500 Firewise USA sites in California to understand participation and demographic trends. We find important regional differences regarding the influence of underlying fire hazard, fire history, and other Firewise sites on new site formation. Sites in the Bay Area and Sierras respond strongly to fire history and proximity to other Firewise sites, while Northern and Southern California have few Firewise sites despite underlying hazardous conditions and large fire history. Firewise sites are often whiter, older, and more well-educated than California’s median population, potentially leaving out many communities that do not meet this demographic profile but face severe risks from wildfires. These findings offer important insights into the factors motivating communities to pursue wildfire protection, particularly important given recent severe and destructive wildfire seasons.