Inner and outer star forming regions over the disks of spiral galaxies. I. Sample characterization

Context. The knowledge of abundance distributions is central to understanding the formation and evolution of galaxies. Most of the relations employed for the derivation of gas abundances have so far been derived from observations of outer disk HII regions, despite the known differences between inner and outer regions. Aims. Using integral field spectroscopy (IFS) observations we aim to perform a systematic study and comparison of two inner and outer HII regions samples. The spatial resolution of the IFS, the number of objects and the homogeneity and coherence of the observations allow a complete characterization of the main observational properties and differences of the regions. Methods. We analyzed a sample of 725 inner HII regions and a sample of 671 outer HII regions, all of them detected and extracted from the observations of a sample of 263 nearby, isolated, spiral galaxies observed by the CALIFA survey. Results. We find that inner HII regions show smaller equivalent widths, greater extinction and luminosities, along with greater values of [NII]{\lambda}6583/H{\alpha} and [OII]{\lambda}3727/[OIII]{\lambda}5007 emission-line ratios, indicating higher metallicites and lower ionization parameters. Inner regions have also redder colors and higher photometric and ionizing masses, although Mion/Mphot is slighty higher for the outer regions. Conclusions. This work shows important observational differences between inner and outer HII regions in star forming galaxies not previously studied in detail. These differences indicate that inner regions have more evolved stellar populations and are in a later evolution state with respect to outer regions, which goes in line with the inside-out galaxy formation paradigm.Comment: 16 page

Reply to "Comment on `Validity of path thermodynamic description of reactive systems: Microscopic simulations'

The Comment's author argues that a correct description of reactive systems should incorporate the explicit interaction with reservoirs, leading to a unified system-reservoirs entity. However, this proposition has two major flaws. Firstly, as we will emphasize, this entity inherently follows a thermodynamic equilibrium distribution. In the Comment, no indication is provided on how to maintain such a system-reservoirs entity in a non-equilibrium state. Secondly, contrary to the author's claim, the inclusion of system-reservoir interaction in traditional stochastic modeling of reactive systems does not automatically alter the limited applicability of path thermodynamics to problematic reactive systems. We will provide a simple demonstration to illustrate that certain elementary reactions may not involve any changes in reservoir components, which seems to have been overlooked by the author.Comment: To appear in Physical Review

Dispersion mécanique de l'or dans les matériaux de surface : exemple du site aurifère de Piéla (Burkina-Faso)

A Piéla, l'or primaire est associé à des filons de quartz, dans une zone de cisaillement des formations volcano-sédimentaires birimiennes (Protérozoïque inférieur). La présence d'or a également été mise en évidence dans les matériaux superficiels latéritiques bien que les roches sous-jacentes et leurs altérites soient en général stériles. L'étude de la répartition de l'or sur les différentes surfaces aplanies montre que l'or est concentré par des transferts mécaniques dans les cailloutis et graviers de cuirasse ferrugineuse et de quartz de la plaine alluviale et dans des portions du moyen-glacis cuirassé assimilables à une ancienne terrasse. Ailleurs sur les surfaces cuirassées (haut-glacis, moyen-glacis), l'or est dispersé à faible teneur ou absent. Les caractères morphologiques et chimiques des particules d'or évoluent depuis la zone minéralisée jusqu'à la plaine alluviale distale ainsi que sur les glacis. Cette évolution se marque par une augmentation de l'émoussé, par des traits morphologiques spécifiques du transport mécanique (stries, bordures repliées, aplatissement) et par un lessivage de l'argent jusqu'au coeur des particules. Dans les matériaux superficiels du site de Piéla, les particules d'or présentent des degrés d'usure différents et ne montrent pas l'évolution progressive avec diminution de la taille des particules et lessivage de l'argent, souvent décrite de bas en haut des profils cuirassés sur roche mère minéralisée. (Résumé d'auteur

RCMS: Risk-Aware Crash Mitigation System for Autonomous Vehicles

We propose a risk-aware crash mitigation system (RCMS), to augment any existing motion planner (MP), that enables an autonomous vehicle to perform evasive maneuvers in high-risk situations and minimize the severity of collision if a crash is inevitable. In order to facilitate a smooth transition between RCMS and MP, we develop a novel activation mechanism that combines instantaneous as well as predictive collision risk evaluation strategies in a unified hysteresis-band approach. For trajectory planning, we deploy a modular receding horizon optimization-based approach that minimizes a smooth situational risk profile, while adhering to the physical road limits as well as vehicular actuator limits. We demonstrate the performance of our approach in a simulation environment.Comment: Presented at the 26th IEEE International Conference on Intelligent Transportation Systems (ITSC) 2023, Bilbao, Bizkaia, Spai

Cooperative Bidirectional Mixed-Traffic Overtaking

Safe overtaking, especially in a bidirectional mixed-traffic setting, remains a key challenge for Connected Autonomous Vehicles (CAVs). The presence of human-driven vehicles (HDVs), behavior unpredictability, and blind spots resulting from sensor occlusion make this a challenging control problem. To overcome these difficulties, we propose a cooperative communication-based approach that utilizes the information shared between CAVs to reduce the effects of sensor occlusion while benefiting from the local velocity prediction based on past tracking data. Our control framework aims to perform overtaking maneuvers with the objective of maximizing velocity while prioritizing safety and passenger comfort. Our method is also capable of reactively adjusting its plan to dynamic changes in the environment. The performance of the proposed approach is verified using realistic traffic simulations.Comment: Published in: 2022 IEEE 25th International Conference on Intelligent Transportation Systems (ITSC

Egg production in the euryhaline tilapia, Sarotherodon melanotheron heudelotii, experimentally maintained in fresh, sea and hypersaline waters

Through the experiments presented here we wanted to test whether egg production of the black-chinned tilapia Sarotherodon melanotheron heudelotii under experimental conditions varies as a function of ambient salinity (fresh waters vs. sea waters vs. hypersaline waters, 0, 35 and 70, respectively) and whether these responses differ between fish acclimated within a few weeks from fresh water to saline and hypersaline environments (experiments E1 and E2, monitoring over 10 and 18 weeks), and individuals born and raised all life long at the experimental salinities (E3, monitoring over 18 weeks). In total, 233 spawns were collected. In each of the three experiments, the reproductive investment (gram of egg per gram of female over 2 weeks) did not differ between salinities of 0 and 35, whereas it was 2-3 times lower at 70 than at 0-35, because of lower spawning frequency (E1-E3), smaller clutch size (E1) and lower spawn mass (E1-E3). Finally, fish acclimated to salinity from fresh water over a few weeks and those maintained at a particular salinity all life long showed similar reproductive traits, thereby emphasizing the remarkable physiological plasticity of this species

Reliable Multicasting via Satellite: Delay Considerations

Many different reliable multicast protocols have been proposed and analyzed in the current literature. Since satellites are naturallya braodcast medium, multicast communications have the potential togreatly benefit from their wide-scale deployment. The performance ofreliable multicast protocols needs to be studied and become betterunderstood over networks including satellite links. Most of the analysisperformed on these protocols has dealt with bandwidth usage, bufferrequirements, and processing delay. Very few studies address thetransmission delay incurred from using reliable multicast protocols. Hybriderror control protocols have been studied in terms of bandwidth and delay.The effects of different estimation schemes coupled with autoparityusage are investigated and results are compared. Simple adaptive mechanismsused with a local recovery scheme are found to offer the best overallresults in terms of reducing recovery latency and satellite bandwidth usage