Taphonomy on vertebrate assemblages recorded in fluvial traps from the Pampean region (Buenos Aires province, Argentina)

Se da a conocer un nuevo modo tafonómico reconocido en un sistema fluvial ubicado en la Región Pampeana (provincia de Buenos Aires, Argentina). Éste se encuentra asociado a cavidades verticales (marmitas) desarrolladas en terrazas del canal principal del río Quequén Grande. Se estudió una asociación de vertebrados actuales (en su mayoría de hábitos acuáticos) acumulados en estas cavidades, las cuales actuaron como trampas para los especímenes. El estudio de la muestra y observaciones realizadas in situ, sugieren que dicha trampa acumuló individuos completos (vivos o muertos) y especímenes aislados durante eventos de alto régimen hídrico (lluvias torrenciales). La representación de partes anatómicas indica una selección de elementos. Se comparó la supervivencia diferencial de cada elemento con diferentes variables (densidad ósea estructural, representación original en el esqueleto, tamaño, forma y volumen), concluyendo que la selección observada se produjo por la capacidad de flotación de los elementos ausentes (p. ej., vértebras).We describe a new taphonomlc mode from a fluvial system developed in channel terraces located at the Pampean Region (Quequén Grande River, Buenos Aires, Argentina) associated with natural vertical cavities («marmits»). We analyzed a recent (mainly aquatic) vertebrate assemblage accumulated in these cavities, which operate as bone traps. Our observations suggest that these traps have accumulated isolated specimens and live or dead complete individuals during high hydric regime (torrential rains). Skeletal part representation indicates that exists a bone selection. We compare the element differential survey with different variables (structural bone density, original representation In a skeleton, size, form and volume), concluding that selection was associated with floating capabilities of missing bones (e.g. vertebrae).Facultad de Ciencias Naturales y Muse

Taphonomy on vertebrate assemblages recorded in fluvial traps from the Pampean region (Buenos Aires province, Argentina)

Se da a conocer un nuevo modo tafonómico reconocido en un sistema fluvial ubicado en la Región Pampeana (provincia de Buenos Aires, Argentina). Éste se encuentra asociado a cavidades verticales (marmitas) desarrolladas en terrazas del canal principal del río Quequén Grande. Se estudió una asociación de vertebrados actuales (en su mayoría de hábitos acuáticos) acumulados en estas cavidades, las cuales actuaron como trampas para los especímenes. El estudio de la muestra y observaciones realizadas in situ, sugieren que dicha trampa acumuló individuos completos (vivos o muertos) y especímenes aislados durante eventos de alto régimen hídrico (lluvias torrenciales). La representación de partes anatómicas indica una selección de elementos. Se comparó la supervivencia diferencial de cada elemento con diferentes variables (densidad ósea estructural, representación original en el esqueleto, tamaño, forma y volumen), concluyendo que la selección observada se produjo por la capacidad de flotación de los elementos ausentes (p. ej., vértebras).We describe a new taphonomlc mode from a fluvial system developed in channel terraces located at the Pampean Region (Quequén Grande River, Buenos Aires, Argentina) associated with natural vertical cavities («marmits»). We analyzed a recent (mainly aquatic) vertebrate assemblage accumulated in these cavities, which operate as bone traps. Our observations suggest that these traps have accumulated isolated specimens and live or dead complete individuals during high hydric regime (torrential rains). Skeletal part representation indicates that exists a bone selection. We compare the element differential survey with different variables (structural bone density, original representation In a skeleton, size, form and volume), concluding that selection was associated with floating capabilities of missing bones (e.g. vertebrae).Facultad de Ciencias Naturales y Muse

Taphonomy on vertebrate assemblages recorded in fluvial traps from the Pampean region (Buenos Aires province, Argentina)

Se da a conocer un nuevo modo tafonómico reconocido en un sistema fluvial ubicado en la Región Pampeana (provincia de Buenos Aires, Argentina). Éste se encuentra asociado a cavidades verticales (marmitas) desarrolladas en terrazas del canal principal del río Quequén Grande. Se estudió una asociación de vertebrados actuales (en su mayoría de hábitos acuáticos) acumulados en estas cavidades, las cuales actuaron como trampas para los especímenes. El estudio de la muestra y observaciones realizadas in situ, sugieren que dicha trampa acumuló individuos completos (vivos o muertos) y especímenes aislados durante eventos de alto régimen hídrico (lluvias torrenciales). La representación de partes anatómicas indica una selección de elementos. Se comparó la supervivencia diferencial de cada elemento con diferentes variables (densidad ósea estructural, representación original en el esqueleto, tamaño, forma y volumen), concluyendo que la selección observada se produjo por la capacidad de flotación de los elementos ausentes (p. ej., vértebras).We describe a new taphonomlc mode from a fluvial system developed in channel terraces located at the Pampean Region (Quequén Grande River, Buenos Aires, Argentina) associated with natural vertical cavities («marmits»). We analyzed a recent (mainly aquatic) vertebrate assemblage accumulated in these cavities, which operate as bone traps. Our observations suggest that these traps have accumulated isolated specimens and live or dead complete individuals during high hydric regime (torrential rains). Skeletal part representation indicates that exists a bone selection. We compare the element differential survey with different variables (structural bone density, original representation In a skeleton, size, form and volume), concluding that selection was associated with floating capabilities of missing bones (e.g. vertebrae).Facultad de Ciencias Naturales y Muse

Local Carrier PWM for Modular Multilevel Converters with Distributed PV Cells and Circulating Current Reduction

Producción CientíficaA new topology has been recently proposed for grid-connected photovoltaic (PV) systems, using modular multilevel converters (MMCs) and distributing PV panels throughout the MMC cells. This topology has two main advantages: it reduces the power losses related to moving the energy into the MMC capacitors from an external source, and it removes the losses and costs related to the DC to DC converters used to track the maximum power point on string converters or central converters, because that task is delegated to MMC cells. However, traditional pulse width modulation (PWM) techniques have many problems when dealing with this application: the distortion at the output increases to unacceptable values when MMC cells target different voltages. This paper proposes a new modulation technique for MMCs with different cell voltages, taking into account the measured cell voltages to generate switching sequences with more accurate timing. It also adapts the modulator sampling period to improve the transitions from level to level, an important issue to reduce the internal circulating currents. The proposed modulation has been validated using simulations that show a consistent behavior in the output distortion throughout a wide operation range, and it also reduces the circulating currents and cuts the conduction losses by half. The behavior of this new topology and this new modulation has been compared to the mainstream topology with external PV panels and also to a fixed carrier modulation

MMC-based topology for grid connection of wind generators with phase and arm power balancing

Producción CientíficaA new topology of a wind farm wherein the wind generators are integrated into the structure of a modular multilevel converter (MMC) is presented. It allows connecting a group of small/medium size wind turbines to the grid, replacing all the grid side converters of the wind generators by the MMC. The different power generated by each wind generator causes power imbalances that can lead to circulating currents; this paper addresses this problem by analyzing it in a simple way. The analysis shows that power differences between phases are naturally balanced by the DC component of circulating current, without the need to use a specific regulator. However, the power differences between the arms result in a high 50 Hz circulating current. This paper presents the design of a new regulator that corrects these power imbalances by generating a phase difference between the upper and lower arm voltages resulting in an optimal 50 Hz circulating current. The operation of the MMC-based wind farm topology has been tested when all the turbines generate the same power and when they generate significantly different powers. Numerical and real-time simulation results show that the proposed regulator keeps the powers of the MMC phases and arms balanced

Aerosol properties over the western Mediterranean basin: temporal and spatial variability

This study focuses on the analysis of Aerosol Robotic Network (AERONET) aerosol data obtained over Alborán Island (35.90° N, 3.03° W, 15 m a.s.l.) in the western Mediterranean from July 2011 to January 2012. Additional aerosol data from the three nearest AERONET stations (Málaga, Oujda and Palma de Mallorca) and the Maritime Aerosol Network (MAN) were also analyzed in order to investigate the temporal and spatial variations of aerosol over this scarcely explored region. High aerosol loads over Alborán were mainly associated with desert dust transport from North Africa and occasional advection of anthropogenic fine particles from central European urban-industrial areas. The fine particle load observed over Alborán was surprisingly similar to that obtained over the other three nearest AERONET stations, suggesting homogeneous spatial distribution of fine particle loads over the four studied sites in spite of the large differences in local sources. The results from MAN acquired over the Mediterranean Sea, Black Sea and Atlantic Ocean from July to November 2011 revealed a pronounced predominance of fine particles during the cruise period.This work was supported by the Andalusia Regional Government through projects P12-RNM-2409 and P10-RNM-6299, by the Spanish Ministry of Science and Technology through projects CGL2010-18782, and CGL2013-45410-R; and by the EU through ACTRIS project (EU INFRA-2010-1.1.16-262254). CIMEL Calibration was performed at the AERONET-EUROPE calibration center, supported by ACTRIS (European Union Seventh Framework Program (FP7/2007-2013) under grant agreement no. 262254

Sunscreen formulations containing rice bran or soybean oil: rheological properties, spreadability and in vitro sun protection factor

The presence of rice bran or soybean oil at different concentrations (3 and 5 %) in gel-creams containing benzophenone-3 (BZ-3) was evaluated. Gel-creams were prepared with Carbopol Ultrez® (polymer) at 0.5 % (w/w). The influence of rice bran or soybean oil was evaluated on the pH values, rheological behavior, spreadability and in vitro sun protection factor (SPF). All formulations showed a creamlike aspect and pH between 6.5 and 7.0. Rheological analysis showed pseudoplastic Non-Newtonian behavior for all formulations according to the Herschel-Bulkley model, regardless of the presence of the oil. However, formulations containing BZ-3 showed higher shear rates and smaller spreadability factors than blank formulations. On the other hand, formulations with higher concentration of vegetable oil showed higher spreadability factors and smaller shear rates than formulations without it. The presence of oil showed no influence on the SPF values of gel-creams.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Landslide Detection in the Himalayas Using Machine Learning Algorithms and U-Net

Event-based landslide inventories are essential sources to broaden our understanding of the causal relationship between triggering events and the occurring landslides. Moreover, detailed inventories are crucial for the succeeding phases of landslide risk studies like susceptibility and hazard assessment. The openly available inventories differ in the quality and completeness levels. Event-based landslide inventories are created based on manual interpretation, and there can be significant differences in the mapping preferences among interpreters. To address this issue, we used two different datasets to analyze the potential of U-Net and machine learning approaches for automated landslide detection in the Himalayas. Dataset-1 is composed of five optical bands from the RapidEye satellite imagery. Dataset-2 is composed of the RapidEye optical data, and ALOS-PALSAR derived topographical data. We used a small dataset consisting of 239 samples acquired from several training zones and one testing zone to evaluate our models’ performance using the fully convolutional U-Net model, Support Vector Machines (SVM), K-Nearest Neighbor, and the Random Forest (RF). We created thirty-two different maps to evaluate and understand the implications of different sample patch sizes and their effect on the accuracy of landslide detection in the study area. The results were then compared against the manually interpreted inventory compiled using fieldwork and visual interpretation of the RapidEye satellite image. We used accuracy assessment metrics such as F1-score, Precision, Recall, and Mathews Correlation Coefficient (MCC). In the context of the Nepali Himalayas, employing RapidEye images and machine learning models, a viable patch size was investigated. The U-Net model trained with 128 × 128 pixel patch size yields the best MCC results (76.59%) with the dataset-1. The added information from the digital elevation model benefited the overall detection of landslides. However, it does not improve the model’s overall accuracy but helps differentiate human settlement areas and river sand bars. In this study, the U-Net achieved slightly better results than other machine learning approaches. Although it can depend on architecture of the U-Net model and the complexity of the geographical features in the imagery, the U-Net model is still preliminary in the domain of landslide detection. There is very little literature available related to the use of U-Net for landslide detection. This study is one of the first efforts of using U-Net for landslide detection in the Himalayas. Nevertheless, U-Net has the potential to improve further automated landslide detection in the future for varied topographical and geomorphological scenes

New Eruptive YSOs from SPICY and WISE

© Published under Creative Commons license CC BY-SA 4.0.This work presents four high-amplitude variable YSOs (≃3 mag at near-or mid-IR wavelengths) arising from the SPICY catalog. Three outbursts show a duration that is longer than 1 year, and are still ongoing. And additional YSO brightened over the last two epochs of NEOWISE observations and the duration of the outburst is thus unclear. Analysis of the spectra of the four sources confirms them as new members of the eruptive variable class. We find two YSOs that can be firmly classified as bona fide FUors and one object that falls in the V1647 Ori-like class. Given the uncertainty in the duration of its outburst, an additional YSO can only be classified as a candidate FUor. Continued monitoring and follow-up of these particular sources is important to better understand the accretion process of YSOs.Peer reviewe