Experimental evaluation of large scale particle tracking velocimetry technique for flow discharge measurements in mountains rivers

Este trabajo presenta una evaluación experimental de una técnica de cuantificación de caudales de aguas superficiales en ríos serranos de la provincia de Córdoba. Los ríos serranos de la provincia de Córdoba se caracterizan por su alta variabilidad temporal definida por la ocurrencia de crecientes repentinas o torrenciales de corta duración y gran velocidad de la corriente (en épocas de lluvias) y por la presencia de periodos extensos de estiaje (período de aguas bajas) con caudales del orden de unos cientos de litros por segundo lo que dificulta la selección de una técnica experimental óptima para todas las condiciones de flujo presentes durante un año. En este trabajo se presenta como alternativa una técnica remota para estimar el caudal escurrido en un curso fluvial en al ámbito serrano implementando a gran escala la técnica de velocimetría por seguimiento de partículas (de sus siglas en inglés LS PTV) la cual puede ser aplicada eficientemente en periodos de aguas bajas y medias con un bajo costo relativo. El campo de velocidad superficial determinado experimentalmente con LS PTV en un curso fluvial sembrado con partículas o trazadores y la batimetría de la sección transversal conocida permiten realizar estimaciones del caudal escurrido. La metodología experimental propuesta es validada con resultados obtenidos utilizando simultáneamente otras técnicas en el río San Antonio en la región serrana de la provincia de Córdoba, en dos secciones diferentes, Cuesta Blanca y Villa Carlos Paz, en condiciones de aguas bajas y medias, respectivamente. Finalmente, se discuten las posibles fuentes de errores involucradas en la implementación de la metodología experimental presentada.This paper presents a validation of an experimental technique for surface water flows discharge measurements in mountain rivers of the of Córdoba province. The mountain rivers of the Córdoba province are characterized by high temporal variability defined by the occurrence of flash floods with very high volumes of fast flows (during the rainy season) and the presence of extended periods of low water conditions with flow rates of the order of a few hundred liters per second which makes difficult the selection of an optimal experimental technique for flow discharge measurement for the different flow conditions present during the year. This paper presents an alternative remote experimental technique, estimating flow discharges in rivers of mountain areas, based on large scale particle tracking velocimetry technique (LS PTV) which can be applied efficiently in periods of low and medium flow conditions with relatively low cost. The surface flow velocity field sampled using LS PTV in a fluvial reach seeded with tracer particles and the cross section bathymetry allow flow discharge estimation. The proposed experimental technique is validated with results obtained using other experimental techniques simultaneously in the San Antonio river in the mountainous region of the of Córdoba province, Argentina, at two different locations (Cuesta Blanca and Villa Carlos Paz). Finally, a discussion is performed on sources of error involved in the implementation of the LS PTV.Fil: Patalano, Antoine. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia Rodriguez, Carlos Marcelo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Guillén, Nicolás Federico. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: García, César Luis. Universidad Católica de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Díaz, Erica Betiana. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodriguez, Andres. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ravelo, Andres Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (p). Grupo Vinculado Centro de Relevamiento y Evaluacion de Recursos Agricolas y Naturales; Argentin

How galaxies populate halos in extreme density environments: An analysis of the halo occupation distribution in SDSS

Context. Recent works have shown that the properties of galaxy populations in simulated dark matter halos vary with large-scale environments. These results suggest a variation in the halo occupation distribution (HOD) in extreme density environments since the dynamical and astrophysical conditions prevailing in these regions may significantly affect the formation and evolution of their halos and residing galaxies, influencing the mean number of satellite galaxies. To analyze these effects, we identify cosmic voids and future virialized structures (FVSs) in the Sloan Digital Sky Server Data Release 12 (SDSS-DR12) and estimate the HOD within these super-structures using group catalogs as dark matter halo proxies. Aims. Our goal is to use observational galaxy data to characterize the HOD within cosmic voids and FVSs, explore the different properties of these galaxiesa'populations, and compare them with the general results outside of these super-structures. Methods. We used a publicly available observational galaxy catalog with information on redshifts, positions, magnitudes, and other astrophysical features to build a volume complete galaxy sample and identify cosmic voids and FVSs. Using a publicly available galaxy group catalog as a proxy to dark matter halos, we computed the HOD within both types of super-structures for different absolute magnitude thresholds. We also studied the dependence of the results on the main void and FVS properties, density, and volume. We also analyzed the main characteristics of the stellar content of galaxies inside these extreme-density regions such as the mean stellar age and the stellar mass. In all cases, we compared the results with those derived from the field sample, defined by objects outside of both types of environments. Results. Inside cosmic voids, we find a strong decrease in the HOD concerning the field results. In the most extreme cases, that is to say groups with masses above ã1013h-1M, the mean number of satellites fall to ã50%. Inside FVSs, the HOD shows a significant increase to the field, with a ã40% excess in the mean number of satellites for groups with masses around 1014h-1M. These results are present for the different galaxy luminosity ranges explored. In both environments, the differences with respect to the field increases for the extreme values of the density environments. However, we obtain no signs of variations related to intrinsic characteristics of the super-structures, indicating that the effects mainly depend on the density of the large-scale environment. In addition, we find that the cumulative distribution of the mean age of stars of the central galaxy also varies in the different regions; this suggests that the history of the formation of the dark matter halos may be different. Finally, we explore the HOD for the 25% youngest (oldest) galaxies, based on the mean age of their stars. We find that for the low-mass groups the youngest galaxies are only present inside voids, and they are generally central galaxies. On the other hand, for the high-mass groups, the FVS environments show the same increase in the HOD concerning the field as previously mentioned. We find that cosmic voids lack a significant fraction of galaxies with the oldest stellar population.Fil: Alfaro, Ignacio Germán. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Rodriguez, Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Ruiz, Andrés Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Luparello, Heliana Estefanía. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Garcia Lambas, Diego Rodolfo. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentin

Functional Recovery and Serum Angiogenin Changes According to Intensity of Rehabilitation Therapy After Stroke

Rehabilitation is still the only treatment available to improve functional status after the acute phase of stroke. Most clinical guidelines highlight the need to design rehabilitation treatments considering starting time, intensity, and frequency, according to the tolerance of the patient. However, there are no homogeneous protocols and the biological effects are under investigation. To investigate the impact of rehabilitation intensity (hours) after stroke on functional improvement and serum angiogenin (ANG) in a 6-month follow-up study. A prospective, observational, longitudinal, and multicenter study with three cohorts: strokes in intensive rehabilitation therapy (IRT, minimum 15 h/week) vs. conventional therapy (NO-IRT, <15 h/week), and controls subjects (without known neurological, malignant, or inflammatory diseases). A total of seven centers participated, with functional evaluations and blood sampling during follow-up. The final cohort includes 62 strokes and 43 controls with demographic, clinical, blood samples, and exhaustive functional monitoring. The median (IQR) number of weekly hours of therapy was different: IRT 15 (15-16) vs. NO-IRT 7.5 (5-9), p < 0.01, with progressive and significant improvements in both groups. However, IRT patients showed earlier improvements (within 1 month) on several scales (CAHAI, FMA, and FAC; p < 0.001) and the earliest community ambulation achievements (0.89 m/s at 3 months). There was a significant difference in ANG temporal profile between the IRT and NO-IRT groups (p < 0.01). Additionally, ANG was elevated at 1 month only in the IRT group (p < 0.05) whereas it decreased in the NO-IRT group (p < 0.05). Our results suggest an association of rehabilitation intensity with early functional improvements, and connect the rehabilitation process with blood biomarkers

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe

Clustering COVID-19 ARDS patients through the first days of ICU admission. An analysis of the CIBERESUCICOVID Cohort

Background Acute respiratory distress syndrome (ARDS) can be classified into sub-phenotypes according to different inflammatory/clinical status. Prognostic enrichment was achieved by grouping patients into hypoinflammatory or hyperinflammatory sub-phenotypes, even though the time of analysis may change the classification according to treatment response or disease evolution. We aimed to evaluate when patients can be clustered in more than 1 group, and how they may change the clustering of patients using data of baseline or day 3, and the prognosis of patients according to their evolution by changing or not the cluster.Methods Multicenter, observational prospective, and retrospective study of patients admitted due to ARDS related to COVID-19 infection in Spain. Patients were grouped according to a clustering mixed-type data algorithm (k-prototypes) using continuous and categorical readily available variables at baseline and day 3.Results Of 6205 patients, 3743 (60%) were included in the study. According to silhouette analysis, patients were grouped in two clusters. At baseline, 1402 (37%) patients were included in cluster 1 and 2341(63%) in cluster 2. On day 3, 1557(42%) patients were included in cluster 1 and 2086 (57%) in cluster 2. The patients included in cluster 2 were older and more frequently hypertensive and had a higher prevalence of shock, organ dysfunction, inflammatory biomarkers, and worst respiratory indexes at both time points. The 90-day mortality was higher in cluster 2 at both clustering processes (43.8% [n = 1025] versus 27.3% [n = 383] at baseline, and 49% [n = 1023] versus 20.6% [n = 321] on day 3). Four hundred and fifty-eight (33%) patients clustered in the first group were clustered in the second group on day 3. In contrast, 638 (27%) patients clustered in the second group were clustered in the first group on day 3.Conclusions During the first days, patients can be clustered into two groups and the process of clustering patients may change as they continue to evolve. This means that despite a vast majority of patients remaining in the same cluster, a minority reaching 33% of patients analyzed may be re-categorized into different clusters based on their progress. Such changes can significantly impact their prognosis