Minor Street Gaps and Capacity at Unsignalized Intersections in Argentina

Capacity analysis for two way stop controlled (TWSC) intersections is mainly based on headway acceptance theory. Critical headways and follow up times are fundamental parameters in capacity estimation. Both factors clearly show the influence of driver behaviour on traffic operations. The critical headway parameter is typically associated with safety and operational performance of this intersection type. This paper explores critical headways and follow up times by analyzing data from video recorded tapes collected in urban intersections located in the city of Cordoba, Argentina in order to derive local values that can be used in capacity estimates at unsignalized intersections. Maximum likelihood methodology and regression analysis are employed. An exponential model is then used to assess the relationships between headways and capacity. Estimates for both headways are significantly smaller than the values given in version 2010 of the Highway Capacity Manual. Increased capacity, due to critical headway and follow up time reductions, becomes proportionally greater as conflicting flows grow. Percent differences increase while curves tend to get closer. From this point of view the conclusion is that intersections operate more efficiently, but also more dangerously.Fil: Depiante, Violeta S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Maestría en Ciencias de la Ingeniería. Mención en Transporte; Argentina.Fil: Galarraga, Jorge J. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Maestría en Ciencias de la Ingeniería. Mención en Transporte; Argentina.Ingeniería del Transport

Caso en el microcentro de la Ciudad de Córdoba

Para avanzar en la movilidad sustentable en ambientes urbanos adquiere gran relevancia la creación de infraestructuras que favorezcan e incentiven el tránsito no motorizado.En muchos casos, el desarrollo de este tipo de obras puede perjudicar la circulación del tránsito motorizado. El presente documento analiza este tipo de impacto, para el caso de una intervención en el centro de la ciudad de Córdoba. Se reportan las tareas desarrolladas empleando el modelo de simulación microscópica NETSIM, con el objetivo de evaluar las condiciones de operación del tránsito vehicular en la situación sin y con proyecto, detallando las conclusiones y recomendaciones pertinentesFil: Rigazio, Rinaldo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Superior de Ingeniería del Transporte; Argentina.Fil: Galarraga, Jorge J. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Superior de ingeniería del Transporte; Argentina.Fil: Herz, Marcelo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Superior de Ingeniería del Transporte; Argentina.Ingeniería del Transport

Photodynamic nasal SARS-CoV-2 decolonization shortens infectivity and influences specific T-Cell responses.

Background: The main objective was to evaluate the efficacy of intranasal photodynamic therapy (PDT) in SARS-CoV-2 mildly symptomatic carriers on decreasing the infectivity period. SARS-CoV-2-specific immune-stimulating effects and safety were also analysed. Methods: We performed a randomized, placebo-controlled, clinical trial in a tertiary hospital (NCT05184205). Patients with a positive SARS-CoV-2 PCR in the last 48 hours were recruited and aleatorily assigned to PDT or placebo. Patients with pneumonia were excluded. Participants and investigators were masked to group assignment. The primary outcome was the reduction in in vitro infectivity of nasopharyngeal samples at days 3 and 7. Additional outcomes included safety assessment and quantification of humoral and T-cell immune-responses. Findings: Patients were recruited between December 2021 and February 2022. Most were previously healthy adults vaccinated against COVID-19 and most carried Omicron variant. 38 patients were assigned to placebo and 37 to PDT. Intranasal PDT reduced infectivity at day 3 post-treatment when compared to placebo with a b-coefficient of -812.2 (CI95%= -478660 – -1.3, p<0.05) infectivity arbitrary units. The probability of becoming PCR negative (ct>34) at day 7 was higher on the PDT-group, with an OR of 0.15 (CI95%=0.04-0.58). There was a decay in anti-Spike titre and specific SARS-CoV-2 T cell immunity in the placebo group 10 and 20 weeks after infection, but not in the PDT-group. No serious adverse events were reported. Interpretation: Intranasal-PDT is safe in pauci-symptomatic COVID-19 patients, it reduces SARS-CoV-2 infectivity and decelerates the decline SARS-CoV-2 specific immune-responses

Coronal Heating as Determined by the Solar Flare Frequency Distribution Obtained by Aggregating Case Studies

Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counter-intuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfv\'en waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold, $\alpha=2$ as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed $>$600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: pre-flare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine that $\alpha = 1.63 \pm 0.03$. This is below the critical threshold, suggesting that Alfv\'en waves are an important driver of coronal heating.Comment: 1,002 authors, 14 pages, 4 figures, 3 tables, published by The Astrophysical Journal on 2023-05-09, volume 948, page 7