Physics-based modeling and data representation of pedestrian pairwise interactions

The possibility to understand and to quantitatively model the physics of the interactions between pedestrians walking in crowds has compelling relevant applications, e.g. related to the design and safety of civil infrastructures. In this work we study pedestrian-pedestrian interactions from observational experimental data in diluted crowds. While in motion, pedestrians adapt their walking paths trying to preserve mutual comfort distances and to avoid collisions. In mathematical models this behavior is typically modeled via "social" interaction forces. Leveraging on a high-quality, high-statistics dataset - composed of few millions of real-life trajectories acquired from state-of-the-art observational experiments - we develop a quantitative model capable of addressing interactions in the case of binary collision avoidance. We model interactions in terms of both long- and short-range forces, which we superimpose to our Langevin model for non-interacting pedestrian motion [Corbetta et al. Phys.Rev.E 95, 032316, 2017]. The new model that we propose here features a Langevin dynamics with "fast" random velocity fluctuations that are superimposed to the "slow" dynamics of a hidden model variable: the "intended" walking path. The model is capable of reproducing relevant statistics of the collision avoidance motion, such as the statistics of the side displacement and of the passing speed. Rare occurrences of bumping events are also recovered. Furthermore, comparing with large datasets of real-life tracks involves an additional challenge so far neglected: identifying, within a database containing very heterogeneous conditions, only the relevant events corresponding to binary avoidance interactions. To tackle this challenge, we propose a novel approach based on a graph representation of pedestrian trajectories, which allows us to operate complexity reduction for efficient data selection.Comment: 17 figures, 18 page

Axial diffusion of respired CO2 confounds stem respiration estimates during the dormant season

Key message: Efflux-based estimates of stem respiration in oak trees during the dormant season were biased by axial diffusion of locally respired CO2. Light-induced axial CO(2)diffusion along the stem due to woody tissue photosynthesis may lead to equivocal estimates of stem respiratory coefficients during the dormant season, which are generally used to estimate maintenance respiration throughout the year. Context: Stem CO2 efflux (E-A) does not reflect respiratory rates of underlying tissues. Recent research has focused on the significance of CO2 transport via the transpiration stream. However, no studies have yet addressed the potential role of light-induced axial CO2 diffusion on E-A during the dormant season when there is no transpiration. Aims: This study investigated to which extent woody tissue photosynthesis and axial diffusion of respired CO2 affect E-A during the dormant season. Methods: E(A) was measured in a stem cuvette on dormant oak trees in a growth chamber at constant temperature. Different rates of axial CO2 diffusion were induced by woody tissue photosynthesis by means of illuminating stem sections at varying distances from the stem cuvette, while light was excluded from the remainder of the tree. Results: Axial diffusion of respired CO2 led to reductions in E-A of up to 22% when the stem section closest to the cuvette was exposed to light. Conclusion: Dormant-season efflux-based estimates of stem respiration might be biased by axial diffusion of respired CO2, particularly in open forest stands with sufficient light penetration. Consequently, this may lead to ambiguous estimates of dormant season E-A coefficients (Q(10) and E-A_0) generally used to estimate maintenance respiration throughout the year

Numerical Assessment and Optimization of Discrete-Variable Time-Frequency Quantum Key Distribution

The discrete variables (DV) time-frequency (TF) quantum key distribution (QKD) protocol is a BB84 like protocol, which utilizes time and frequency as complementary bases. As orthogonal modulations, pulse position modulation (PPM) and frequency shift keying (FSK) are capable of transmitting several bits per symbol, i.e. per photon. However, unlike traditional binary polarization shift keying, PPM and FSK do not allow perfectly complementary bases. So information is not completely deleted when the wrong-basis filters are applied. Since a general security proof does not yet exist, we numerically assess DV-TF-QKD. We show that the secret key rate increases with a higher number of symbols per basis. Further we identify the optimal pulse relations in the two bases in terms of key rate and resistance against eavesdropping attacks.Comment: 9 Pages, 4 Figure

COMPARAÇÃO ECONÔMICA DE DIFERENTES MECANISMOS SULCADORES DE SEMEADORAS EM PLANTIO DIRETO DE MILHO

A semeadura direta é caracterizada pela mínima mobilização do solo durante operação, com emprego de máquinas específicas, logo, as semeadoras-adubadoras passaram a ter importância fundamental nestes sistemas de produção. Diante do exposto objetivou-se com o trabalho avaliar o custo operacional efetivo por hectare de uma semeadura de milho com diferentes mecanismos sulcadores. O delineamento experimental utilizado foi o de blocos casualizados com quatro repetições, em esquema fatorial 2 x 2, sendo o primeiro fator compreendido por mecanismos de abertura de sulco (haste sulcadora e disco duplo) e o segundo por espaçamentos entre fileiras da cultura do milho (reduzido - 0,45m e convencional - 0,90m). Os resultados demonstraram que houve diferença significativa para o custo operacional por hectare, sendo os menores custos por hectare, ao utilizar o mecanismo sulcador tipo disco duplo, no espaçamento entre fileiras reduzido

The Artinskian Siderópolis Member macroflora, Rio Bonito Formation and its stratigraphical correlation with other early Permian macrofloras of Paraná Basin, Brazil

An overview of the composition of the paleoflora preserved in clay-siltstones of the Siderópolis Member, Rio Bonito Formation is presented in order to establish phytostratigraphical comparisons with other Late Pennsylvanian and Cisuralian paleofloras of the Paraná Basin. The Rio Bonito Formation, the most important of the coal bearing lithostratigraphic units of the Paraná Basin belongs to the Gondwana I Supersequence (Pennsylvanian-Early Triassic). The Siderópolis paleoflora occurs in the uppermost layers of coal of Rio Bonito Formation in Santa Catarina coalfield in four distinct localities of the State of Santa Catarina: Lauro Muller, Criciúma, São Marcos and Treviso. In this paleoflora the glossopterid leaves predominate with an evident dominance of the genus Glossopteris over Gangamopteris, followed by Cordaitalean leaves (Noeggerathiopsis) and seeds (Cordaicarpus, Samaropsis, Cornucarpus). Sterile fronds are common and few are fertile (Sphenopteris, Pecopteris, Ponsotheca and Notoangaridium). Pteridosperm reproductive structures (Arberia, Arberiopsis, Ottokaria) are not frequent and branches of conifers (Brasilocladus, Buriadia) are rare. Concerning other paleofloras of the basin, the Siderópolis paleoflora is distinguished by high diversity and many exclusive taxa showing only few similarities with some paleofloras registered in Rio Grande do Sul, occurring in outcrops of the Rio Bonito Formation such as Morro do Papaléo (upper section) and Quitéria. The differences may reflect an upper stratigraphic position, but may also indicate differences in sedimentation and / or in paleoecological conditions.Apresenta-se aqui uma síntese da composição da paleoflora preservada em siltitos argilosos do Membro Siderópolis, Formação Rio Bonito tendo como objetivo estabelecer comparações fitoestratigráficas com outras paleofloras neopensilvanianas e cisuralianas da Bacia do Paraná. A Formação Rio Bonito, a mais importante das unidades litoestratigráficas portadoras de carvão da Bacia do Paraná, pertence à supersequência Gondwana I (Pensilvaniano-Eotriássico). A paleoflora Siderópolis ocorre nas camadas de carvão mais superiores da Formação Rio Bonito na região carvoeira de Santa Catarina, em quatro áreas distintas do Estado de Santa Catarina: Lauro Muller, Criciúma, São Marcos e Treviso. Na paleoflora, as folhas de glossopterídeas predominam com um evidente domínio do gênero Glossopteris sobre Gangamopteris, seguido por folhas cordaitaleanas (Noeggerathiopsis) e sementes (Cordaicarpus, Samaropsis, Cornucarpus). Frondes estéreis são comuns havendo poucas férteis (Sphenopteris, Pecopteris, Ponsotheca, Notoangaridium). Estruturas reprodutivas pteridospérmicas  (Arberia, Arberiopsis, Ottokaria) e ramos de coníferas (Brasilocladus, Buriadia) são raros. Em relação a outras paleofloras da bacia, a de Siderópolis distingue-se por apresentar diversidade mais alta e muitos táxons exclusivos mostrando apenas umas poucas semelhanças com algumas paleofloras registradas no Rio Grande do Sul, ocorrendo em afloramentos do Rio Bonito tais como Morro do Papaléo (porção superior) e Quitéria. Essas diferenças podem refletir uma posição estratigráfica superior, mas pode também indicar diferenças em condições de sedimentação e / ou paleoecológicas

Closed magnetic topology in the Venusian magnetotail and ion escape at Venus.

Venus, lacking an intrinsic global dipole magnetic field, serves as a textbook example of an induced magnetosphere, formed by interplanetary magnetic fields (IMF) enveloping the planet. Yet, various aspects of its magnetospheric dynamics and planetary ion outflows are complex and not well understood. Here we analyze plasma and magnetic field data acquired during the fourth Venus flyby of the Parker Solar Probe (PSP) mission and show evidence for closed topology in the nightside and downstream portion of the Venus magnetosphere (i.e., the magnetotail). The formation of the closed topology involves magnetic reconnection-a process rarely observed at non-magnetized planets. In addition, our study provides an evidence linking the cold Venusian ion flow in the magnetotail directly to magnetic connectivity to the ionosphere, akin to observations at Mars. These findings not only help the understanding of the complex ion flow patterns at Venus but also suggest that magnetic topology is one piece of key information for resolving ion escape mechanisms and thus the atmospheric evolution across various planetary environments and exoplanets

The consistency of the treatment effect of an ACE-inhibitor based treatment regimen in patients with vascular disease or high risk of vascular disease: A combined analysis of individual data of ADVANCE, EUROPA, and PROGRESS trials

AimsAngiotensin-converting enzyme (ACE) inhibitors have been shown to reduce cardiovascular risk in different groups of patients. Whether these effects can be generalized to the broad group of patients with vascular disease is unknown. Therefore, we undertook a combined analysis using individual data from ADVANCE, EUROPA, and PROGRESS to determine the consistency of the treatment effect of perindopril-based regimen in patients with vascular disease or at high risk of vascular disease.Methods and resultsWe studied all-cause mortality and major cardiovascular outcomes during a follow-up of about 4 years in the 29 463 patients randomly assigned a perindopril-based treatment regimen or placebo. The perindopril-based regimens were associated with a significant reduction in all-cause mortality [hazard ratio (HR) 0.89; 95 confidence interval (CI) 0.82-0.96; P = 0.006], cardiovascular mortality (HR 0.85; 95 CI 0.76-0.95; P = 0.004), non-fatal myocardial infarction (HR 0.80; 95 CI 0.71-0.90; P < 0.001), stroke (HR 0.82; 95 CI 0.74-0.92; P = 0.002), and heart failure (HR 0.84; 95 CI 0.72-0.96; P = 0.015). Results were consistent in subgroups with different clinical characteristics, concomitant medication use, and across all strata of baseline blood pressure.ConclusionThis study provides strong evidence for a consistent cardiovascular protection with an ACE-inhibitor treatment regimen (perindopril-indapamide) by improving survival and reducing the risk of major cardiovascular events across a broad spectrum of patients with vascular disease

Individualized angiotensin-converting enzyme (ACE)-inhibitor therapy in stable coronary artery disease based on clinical and pharmacogenetic determinants: The PERindopril GENEtic (PERGENE) risk model

Background-Patients with stable coronary artery disease (CAD) constitute a heterogeneous group in which the treatment benefits by angiotensin-converting enzyme (ACE)-inhibitor therapy vary between individuals. Our objective was to integrate clinical and pharmacogenetic determinants in an ultimate combined risk prediction model. Methods and Results-Clinical, genetic, and outcomes data were used from 8726 stable CAD patients participating in the EUROPA/PERGENE trial of perindopril versus placebo. Multivariable analysis of phenotype data resulted in a clinical risk score (range, 0-21 points). Three single-nucleotide polymorphisms (rs275651 and rs5182 in the angiotensin-II type I-receptor gene and rs12050217 in the bradykinin type I-receptor gene) were used to construct a pharmacogenetic risk score (PGXscore; range, 0-6 points). Seven hundred eighty-five patients (9.0%) experienced the primary endpoint of cardiovascular mortality, nonfatal myocardial infarction or resuscitated cardiac arrest, during 4.2 years of follow-up. Absolute risk reductions ranged from 1.2% to 7.5% in the 73.5% of patients with PGXscore of 0 t