2,167 research outputs found

    Traffic Behavior on São Paulo's Streets: A Post-Pandemic Study

    Get PDF
    This study examines São Paulo's post-COVID-19 traffic conditions after adopting a new data collection system in partnership with Waze. São Paulo, with over 6 million cars, 12 million people, and 20,000 km of roads, analyzed data from May 2020 to September 2023. Traffic patterns varied significantly on different weekdays. Mondays had lower volume (6.7 million vehicles) and congestion (76 km), while Tuesdays and Wednesdays had intermediate levels (6.6 million vehicles and 100 km, respectively). Thursdays and Fridays showed higher volume (6.7 million vehicles) and increased congestion (110 km). The study demonstrated a strong relationship between volume and traffic slowdown, reflecting economic recovery

    Changing urban mobility habits in Sao Paulo: An analysis from 2017 to 2022

    Get PDF
    The COVID-19 pandemic had a significant impact on urban mobility and public transpor-tation. While some restrictions have eased, passenger volumes remain lower than pre-pandemic levels. In 2022, global averages were 26% below 2017 figures. Public transport is crucial for urban sustainability and citizens' rights, but it relies on passengers for viability. Our study focuses on the Metropolitan Region of São Paulo, analyzing passenger numbers from 2017 to 2022 for subways, urban rail, city buses, and metropolitan buses, along with individual motorized transport. The data reveals decline during the pandemic and a gradual recovery in 2022, with drops of 15% in subways, 28% in urban rail, 32% in city buses, and 20% in metropolitan buses compared to 2017. This study underscores the challenges and prospects for mobility in the region, reflecting changing habit

    Urban public transport trends in five western international metropolises: A post-pandemic perspective

    Get PDF
    This study analyzes demand fluctuations in urban public transportation systems of São Paulo, New York, Paris, London, and Mexico City before and after the Covid-19 pandemic in 2020. We examined annual passenger data from 2017 to 2022. Pre-pandemic, São Paulo and London saw declining trends, while Paris, New York, and Mexico City remained relatively stable, with minor fluctuations. The pandemic caused a sharp drop in passengers in April and May 2020, followed by varying degrees of recovery. Paris had a robust recovery, São Paulo, London, and Mexico City re- covered differently, and New York had a slower rebound. Subway and urban train systems showed stronger recoveries compared to urban buses. Overall, post-pandemic recovery was positive, with a gradual passenger increase each year but still below 2017 levels, indicating changed mobility habits

    Simulating the behavior of the human brain on GPUS

    Get PDF
    The simulation of the behavior of the Human Brain is one of the most important challenges in computing today. The main problem consists of finding efficient ways to manipulate and compute the huge volume of data that this kind of simulations need, using the current technology. In this sense, this work is focused on one of the main steps of such simulation, which consists of computing the Voltage on neurons’ morphology. This is carried out using the Hines Algorithm and, although this algorithm is the optimum method in terms of number of operations, it is in need of non-trivial modifications to be efficiently parallelized on GPUs. We proposed several optimizations to accelerate this algorithm on GPU-based architectures, exploring the limitations of both, method and architecture, to be able to solve efficiently a high number of Hines systems (neurons). Each of the optimizations are deeply analyzed and described. Two different approaches are studied, one for mono-morphology simulations (batch of neurons with the same shape) and one for multi-morphology simulations (batch of neurons where every neuron has a different shape). In mono-morphology simulations we obtain a good performance using just a single kernel to compute all the neurons. However this turns out to be inefficient on multi-morphology simulations. Unlike the previous scenario, in multi-morphology simulations a much more complex implementation is necessary to obtain a good performance. In this case, we must execute more than one single GPU kernel. In every execution (kernel call) one specific part of the batch of the neurons is solved. These parts can be seen as multiple and independent tridiagonal systems. Although the present paper is focused on the simulation of the behavior of the Human Brain, some of these techniques, in particular those related to the solving of tridiagonal systems, can be also used for multiple oil and gas simulations. Our studies have proven that the optimizations proposed in the present work can achieve high performance on those computations with a high number of neurons, being our GPU implementations about 4× and 8× faster than the OpenMP multicore implementation (16 cores), using one and two NVIDIA K80 GPUs respectively. Also, it is important to highlight that these optimizations can continue scaling, even when dealing with a very high number of neurons.This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No. 720270 (HBP SGA1), from the Spanish Ministry of Economy and Competitiveness under the project Computación de Altas Prestaciones VII (TIN2015-65316-P), the Departament d’Innovació, Universitats i Empresa de la Generalitat de Catalunya, under project MPEXPAR: Models de Programació i Entorns d’Execució Parallels (2014-SGR-1051). We thank the support of NVIDIA through the BSC/UPC NVIDIA GPU Center of Excellence, and the European Union’s Horizon 2020 Research and Innovation Program under the Marie Sklodowska-Curie Grant Agreement No. 749516.Peer ReviewedPostprint (published version

    cuHinesBatch: solving multiple hines systems on GPUs Human Brain Project

    Get PDF
    The simulation of the behavior of the Human Brain is one of the most important challenges today in computing. The main problem consists of finding efficient ways to manipulate and compute the huge volume of data that this kind of simulations need, using the current technology. In this sense, this work is focused on one of the main steps of such simulation, which consists of computing the Voltage on neurons’ morphology. This is carried out using the Hines Algorithm. Although this algorithm is the optimum method in terms of number of operations, it is in need of non-trivial modifications to be efficiently parallelized on NVIDIA GPUs. We proposed several optimizations to accelerate this algorithm on GPU-based architectures, exploring the limitations of both, method and architecture, to be able to solve efficiently a high number of Hines systems (neurons). Each of the optimizations are deeply analyzed and described. To evaluate the impact of the optimizations on real inputs, we have used 6 different morphologies in terms of size and branches. Our studies have proven that the optimizations proposed in the present work can achieve a high performance on those computations with a high number of neurons, being our GPU implementations about 4× and 8× faster than the OpenMP multicore implementation (16 cores), using one and two K80 NVIDIA GPUs respectively. Also, it is important to highlight that these optimizations can continue scaling even when dealing with number of neurons.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 720270 (HBP SGA1), from the Spanish Ministry of Economy and Competitiveness under the project Computación de Altas Prestaciones VII (TIN2015-65316-P) and the Departament d’Innovació, Universitats i Empresa de la Generalitat de Catalunya, under project MPEXPAR: Models de Programació i Entorns d’Execució Paral·lels (2014-SGR-1051). We thank the support of NVIDIA through the BSC/UPC NVIDIA GPU Center of Excellence. Antonio J. Peña is cofinanced by the Spanish Ministry of Economy and Competitiveness under Juan de la Cierva fellowship number IJCI-2015-23266.Peer ReviewedPostprint (published version

    Análise espacial de viagens em transporte público na Região Metropolitana de Campinas-SP

    Get PDF
    A alta dependência do uso do transporte individual e a ausência de planejamento da mobilidade têm se mostrado insustentáveis para o meio urbano e para a qualidade de vida da população. Na busca pela mitigação destes problemas e promoção de uma mobilidade mais sustentável, indicadores de mobilidade sustentável se mostram excelentes ferramentas de gestão. O presente estudo tem como objetivo analisar a distribuição espacial do indicador de viagens realizadas em transporte público da Região Metropolitana de Campinas (RMC), a partir de dados levantados pela Pesquisa Origem Destino de 2011, coordenada pela Secretaria de Transportes Metropolitanos do Estado de São Paulo. Foram utilizadas técnicas de econometria espacial que permitiram avaliar a distribuição espacial do indicador “viagens realizadas em modos coletivos”. Os resultados alcançados identificaram valor significativo para o I de Moran (0,485). A zona com maior uso do transporte público coletivo, apresentou 1,13 viagens per capita, já a zona com menor uso, apresentou 0,18 viagens per capita, confirmando o baixo uso do transporte público em toda a região metropolitana

    Variable batched DGEMM

    Get PDF
    Many scientific applications are in need to solve a high number of small-size independent problems. These individual problems do not provide enough parallelism and then, these must be computed as a batch. Today, vendors such as Intel and NVIDIA are developing their own suite of batch routines. Although most of the works focus on computing batches of fixed size, in real applications we can not assume a uniform size for all set of problems. We explore and analyze different strategies based on parallel for, task and taskloop OpenMP pragmas. Although these strategies are straightforward from a programmer's point of view, they have a different impact on performance. We also analyze a new prototype provided by Intel (MKL), which deals with batch operations (cblas dgemm batch). We propose a new approach called grouping. It basically groups a set of problems until filling a limit in terms of memory occupancy or number of operations. In this way, groups composed by different number of problems are distributed on cores, achieving a more balanced distribution in terms of computational cost. This strategy is able to be up to 6× faster than the Intel (MKL) batch routineThis project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 720270 (HBP SGA1), from the Spanish Ministry of Economy and Competitiveness under the project Computacion de Altas Prestaciones VII (TIN2015-65316-P) and the Departament d’Innovacio, Universitats i Empresa de la Generalitat de Catalunya, under project MPEXPAR: Models de Programacio i Entorns d’Execucio Paral·lels (2014-SGR-1051).Peer ReviewedPostprint (author's final draft

    Lipoic acid inhibits leptin secretion and Sp1 activity in adipocytes

    Get PDF
    Lipoic acid (LA) is an antioxidant with therapeutic potential on several diseases such as diabetes and obesity. Hyperleptinemia and oxidative stress play a major role in the development of obesity-linked diseases. The aim of this study was to examine in vivo and in vitro the effects of LA on leptin production, as well as to elucidate the mechanisms and signalling pathways involved in LA actions. Methods and results: Dietary supplementation with LA decreased both circulating leptin, and adipose tissue leptin mRNA in rats. Treatment of 3T3-L1 adipocytes with LA caused a concentration-dependent inhibition of leptin secretion and gene expression. Moreover, LA stimulated the anaerobic utilization of glucose to lactate, which negatively correlated with leptin secretion. Furthermore, LA enhanced phosphorylation of Sp1 and inhibited Sp1 transcriptional activity in 3T3-L1 adipocytes. Moreover, LA inhibited Akt phosphorylation, a downstream target of phosphatidylinositol 3-kinase (PI3K). Treatment with the PI3K inhibitor LY294002 mimicked LA actions, dramatically inhibiting both leptin secretion and gene expression and stimulating Sp1 phosphorylation. Conclusion: All of these data suggest that the phosphorylation of Sp1 and the accompanying reduced DNA-binding activity are likely to be involved in the inhibition of leptin induced by LA, which could be mediated in part by the abrogation of the PI3K/Akt pathway

    Living at a geographically higher elevation is associates with lower risk oof metabolic syndrome: prospective analysis of the SUN Cohort

    Get PDF
    Living in a geographically higher altitude affects oxygen availability. The possible connection between environmental factors and the development of metabolic syndrome (MetS) feature is not fully understood, being the available epidemiological evidence still very limited. The aim of the present study was to evaluate the longitudinal association between altitude and incidence of MetS and each of its components in a prospective Spanish cohort, The Seguimiento Universidad de Navarra (SUN) project. Our study included 6860 highly educated subjects (university graduates) free from any MetS criteria at baseline. The altitude of residence was imputed with the postal code of each individual subject residence according to the data of the Spanish National Cartographic Institute and participants were categorized into tertiles. MetS was defined according to the harmonized definition. Cox proportional hazards models were used to assess the association between the altitude of residence and the risk of MetS during follow-up. After a median follow-up period of 10 years, 462 incident cases of MetS were identified. When adjusting for potential confounders, subjects in the highest category of altitude (>456m) exhibited a significantly lower risk of developing MetS compared to those in the lowes ttertile (<122m) of altitude of residence [Model2:Hazardratio=0.75(95%Confidenceinterval:0.58–0.97);pfortrend=0.029]. Living at geographically higher altitude was associated with alower risk of developing MetS in the SUN project. Our findings suggest that geographical elevation may be an important factor linked to metabolic diseases

    Nuclear astrophysics with radioactive ions at FAIR

    Get PDF
    R. Reifarth et al: ; 12 págs.; 9 figs.; Open Access funded by Creative Commons Atribution Licence 3.0 ; Nuclear Physics in Astrophysics VI (NPA6)The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process ow and r-process -decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will oer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.This project was supported by the HGF Young Investigators Project VH-NG-327, EMMI, H4F, HGS-HIRe, JINA, NAVI, DFG and ATHENA.Peer Reviewe
    corecore