Estimation of Avalanche Development and Frontal Velocities Based on the Spectrogram of the Seismic Signals Generated at the Vallée de la Sionne Test Site.

The changes in the seismic signals generated by avalanches recorded at three sites along a path at the Vallée de la Sionne (VdlS) experimental site are presented. We discuss and correlate the differences in the duration, signal amplitudes, and frequency content of the sections (Signal ONset (ON), Signal Body (SBO), and Signal TAil and Signal ENd STA-SEN) of the spectrograms with the evolution of the powder, transitional and wet snow avalanches along a path. The development of the avalanche front was quantified using the exponential function in time F (t) = K' exp (β t) fitted to the shape of the signal ONset (SON section of the spectrogram. The speed of the avalanche front is contained in β. To this end, a new method was developed. The three seismic components were converted into one seismic component (FS), when expressing the vector in polar coordinates. We linked the theoretical function of the shape of the FS-SON section of the spectrogram to the numerical coefficients of its shape after considering the spectrogram as an image. This allowed us to obtain the coefficients K' and β. For this purpose, the Hough Transform (HT) was applied to the image. The values of the resulting coefficients K' and β are included in different ranges in accordance with the three types of avalanche. Curves created with these coefficients enable us to estimate the development of the different avalanche types along the path. Our results show the feasibility of classifying the type of avalanche through these coefficients. Average speeds of the avalanches approaching the recording sites were estimated. The speed values of wet and transitional avalanches are consistent with those derived from GEODAR (GEOphysical Doppler radAR) measurements, when available. The absence of agreement in the speed values obtained from seismic signals and GEODAR measurements for powder snow avalanches indicates, for this type of avalanche, a different source of the measured signal. Hence, the use of the two measuring systems proves to be complementary

Seismic data of a rockslide: Evaluation of noise levels, site effects, frequency content and identification of seismic phases

Seismic data can provide information to deduce the occurrence of mass movement events, their release time, event location and dynamics characterization [1]. Nevertheless, the effect of local site amplifications, the level of seismic noise and the frequency content of the signals are important constraints to correctly identify and describe these types of events. In this article we provide data on: site effects, power spectral densities, polarization particle motion and spectrograms generated by a rockslide (∼450 m3) (hereinafter NR) recorded in two permanent seismic stations (EPOB and POBL) located ∼10 km from the source. Original data are available through the International Federation of Digital Seismograph Networks (FDSN, http://www.fdsn.org) for POBL and on request from Instituto Geográfico Nacional (IGN, http://www.ign.es) for EPOB. POBL and EPOB site effects analysis by means of Horizontal-to-Vertical spectral ratio (H/V) technique shows important signatures in POBL signal between 1 and 10 Hz, indicating strong amplification effects at these frequencies, not present in EPOB. For frequencies >1 Hz, Power Spectral Densities (PSD) are higher in POBL than in EPOB, indicating that POBL is noisier than EPOB. Based on the H/V and PSD analyzes, the EPOB station data was deemed preferable over the POBL, to conduct the research presented in the related article [1]. Particle polarization motion data enabled the identification of the arrivals of P, S, and superficial waves, confirming that Pg waves were correctly identified, providing necessary information for the event location in the research article [1]. Moreover, EPOB and POBL spectrograms together with the Fourier transform are included to analyze their content in the frequency domain showing that the expected high frequency phenomenon of the rockslide recorded at 10 km is attenuated and only the low frequency content between 1 and 15 Hz is recorded

Seasonal niche of planktonic prokaryotes inhabiting surface waters of the upwelling region off NW Iberia

Prokaryotes play an important role in biogeochemical cycling in marine ecosystems, but little is known about their diversity and composition, and it’s even less understood how they may contribute to the ecological functioning of highly variable coastal areas affected by upwelling. Between May 2016 and May 2018, we carried out 26 one-day samplings in the temperate northwestern Iberian upwelling system to investigate the temporal patterns of variability for prokaryotic abundance, diversity and community composition by combining flow cytometry and 16S RNA high- throughput sequencing. A marked seasonality was found for prokaryotic abundance, peaking during summer upwelling and relaxation season (≈May to September), when extracellular release of organic matter from phytoplanktonic blooms is a significant process, and decreasing in downwelling events (≈October to April). Those downwelling conditions, characterized by deeper mixed layers and a homogeneous water column, favored a higher abundance of the archaeal groups, Marine Group II (Euryarchaeota) and Nitrosopelagicus (Thaumarchaeota), as well as of Marinimicrobia bacterium (SAR406 clade) and the group Bacteria_Others. By contrast, upwelling and relaxation conditions characterized by enhanced vertical stratification and hydrographic variability, included a community generally less diverse with core-phylotypes (occurring > 75% of the samples) proliferating, i.e. Flavobacteriaceae (Bacteroidetes), Chloroplast (Cyanobacteria) and Amylibacter (Proteobacteria). Overall, the environmental conditions explained 60% (R2=0.60, AIC=125.64) of the prokaryotic community composition, being temperature, inorganic nutrients, chlorophyll and particulate organic nitrogen the variables that best explained the variation in the prokaryotic community composition (r=0.40). Additional efforts are currently underway on a fine-tuning composition assessment (oligotypes composition from particular core-phylotypes) to study if this variability along the temporal environmental gradient could be associated with the differentiation of ecotypes (oligotype ́s seasonality within particular phylotypes). Overall, the present study provides new insights into the barely explored seasonal niche partitioning of surface prokaryotic community driven by hydrodynamic forcing in an upwelling system, which may support further investigations on the role of bacterioplankton in the biogeochemistry of these ecosystems

Seasonal niche of planktonic prokaryotes inhabiting surface waters of the upwelling region off NW Iberia

Oral communicationProkaryotes play an important role in biogeochemical cycling in marine ecosystems, but little is known about their diversity and composition, and it’s even less understood how they may contribute to the ecological functioning of highly variable coastal areas affected by upwelling. Between May 2016 and May 2018, we carried out 26 one-day samplings in the temperate northwestern Iberian upwelling system to investigate the temporal patterns of variability for prokaryotic abundance, diversity and community composition by combining flow cytometry and 16S RNA high- throughput sequencing. A marked seasonality was found for prokaryotic abundance, peaking during summer upwelling and relaxation season (≈May to September), when extracellular release of organic matter from phytoplanktonic blooms is a significant process, and decreasing in downwelling events (≈October to April). Those downwelling conditions, characterized by deeper mixed layers and a homogeneous water column, favored a higher abundance of the archaeal groups, Marine Group II (Euryarchaeota) and Nitrosopelagicus (Thaumarchaeota), as well as of Marinimicrobia bacterium (SAR406 clade) and the group Bacteria_Others. By contrast, upwelling and relaxation conditions characterized by enhanced vertical stratification and hydrographic variability, included a community generally less diverse with core-phylotypes (occurring > 75% of the samples) proliferating, i.e. Flavobacteriaceae (Bacteroidetes), Chloroplast (

Plan de negocio para implementar un centro especializado de hemodi?lisis en la regi?n de Hu?nuco

La poblaci?n de regiones como Hu?nuco y Pasco son muy vulnerables a sufrir enfermedades renales cr?nicas; sin embargo, no cuentan con espacios adecuados para un debido tratamiento y el sector p?blico no logra cubrir toda la demanda, por lo cual los pacientes de la regi?n centro del pa?s deben de trasladarse constantemente hasta la ciudad de Lima, esto no s?lo los afecta econ?micamente, sino que incide de modo negativo en su calidad de vida. Ante esta problem?tica, la implementaci?n de un centro que brinde el servicio de hemodi?lisis, no s?lo es necesario, sino que, ante esta situaci?n, se hace urgente

Free as a Bird: Event-Based Dynamic Sense-and-Avoid for Ornithopter Robot Flight

Autonomous flight of flapping-wing robots is a major challenge for robot perception. Most of the previous sense-and-avoid works have studied the problem of obstacle avoidance for flapping-wing robots considering only static obstacles. This letter presents a fully onboard dynamic sense-and-avoid scheme for large-scale ornithopters using event cameras. These sensors trigger pixel information due to changes of illumination in the scene such as those produced by dynamic objects. The method performs event-by-event processing in low-cost hardware such as those onboard small aerial vehicles. The proposed scheme detects obstacles and evaluates possible collisions with the robot body. The onboard controller actuates over the horizontal and vertical tail deflections to execute the avoidance maneuver. The scheme is validated in both indoor and outdoor scenarios using obstacles of different shapes and sizes. To the best of the authors’ knowledge, this is the first event-based method for dynamic obstacle avoidance in a flapping-wing robot.Consejo Europeo de Investigación (ERC) 788247Comisión Europea - Proyecto AERIAL-CORE H2020-2019-871479Ministerio de Universidades FPU19/0469

Neuropsychological assessment and perinatal risk: A study amongst very premature born 4- and 5-year old children

Background: Prematurity and its consequences are serious problems that can result in numerous neurosensory disabilities and cerebral cognitive dysfunctions. The Perinatal Risk Index (PERI) might provide a predictive measure of these problems. Aim: This study compared the cognitive development of prematurely born children at 4 and 5 years of age with age-matched peers born at term. The secondary objective was to determine whether a correlation exists between perinatal risk and performance on neuropsychological tests among premature children. Methods: A total of 54 children between four and five years of age were evaluated; 27 were born very premature (premature group; PG), and 27 were born at term (term group; TG). Executive function, attention, memory, language, visual perception, and spatial structuring were evaluated. Subtests from the Kaufman Assessment Battery for Children, the Rey Complex Figure Test, the McCarthy Scales of Children’s Abilities, the Peabody Picture Vocabulary Test, Test A, Trails A and B, the spatial structuring questionnaire from the Child Neuropsychological Maturity Questionnaire, and the Wechsler Intelligence Scale for Children were used. A PERI score was also obtained for the PG. Results: The PG showed significantly lower scores than the TG in all the studied cognitive domains. Visual-perceptive scores were significantly and negatively correlated with the PERI scores of the PG. Conclusions: The PG showed neurocognitive deficits compared with the TG. The PERI can be used to predict the development of visual-perceptive abilities in children between four and five years of age

Palatini versus metric formulation in higher curvature gravity

We compare the metric and the Palatini formalism to obtain the Einstein equations in the presence of higher-order curvature corrections that consist of contractions of the Riemann tensor, but not of its derivatives. We find that there is a class of theories for which the two formalisms are equivalent. This class contains the Palatini version of Lovelock theory, but also more Lagrangians that are not Lovelock, but respect certain symmetries. For the general case, we find that imposing the Levi-Civita connection as an Ansatz, the Palatini formalism is contained within the metric formalism, in the sense that any solution of the former also appears as a solution of the latter, but not necessarily the other way around. Finally we give the conditions the solutions of the metric equations should satisfy in order to solve the Palatini equations.Comment: 13 pages, latex. V2: reference added, major changes in section 3, conclusions partially correcte