2,146 research outputs found
Flow blurring atomization of Poly(ethylene oxide) solutions below the coil overlap concentration
Atomization of polymer solutions has important technological implications across many fields. Here, we investigated the atomization dynamics of diluted, polymer solutions using Flow Blurring (FB) technology. Aqueous solutions of poly(ethylene oxide) [PEO] of viscosity-averaged molecular weight in the range 100000 g/mol – 4000000 g/mol and varying concentrations were sprayed with a FB atomizer having an orifice diameter (D) of 700μm and a liquid feed-tube-to-orifice separation (H) of 100μm. The solutions belong to the dilute regime, where polymer coil overlap does not occur, that is φ= [Formula presented] <φcrit (Modesto-López, Pérez-Arjona, & Gañán-Calvo, 2019). Shear viscosity measurements indicated that the solutions had viscosities of the order of that of the solvent and exhibited a Newtonian-like behavior. However, during the atomization, and due to the relatively high shear stress induced in the atomizer, the solutions exhibit extensional rheology, which most likely arises from the stretching of the polymer chains in-flight. Although initially the atomization resulted in formation of filaments, these broke up into droplets at relatively short distances from the atomizer discharge orifice as elucidated by images from ultra-high speed videos. The phenomenon is in contrast with that observed in FB-based atomization of semi-diluted polymer solutions with concentrations larger than the polymer coil overlap concentration, c∗. FB atomization of the diluted solutions resulted in a decrease in droplet size with increasing the gas-to-liquid mass ratio (GLR). The approach herein aims at understanding the droplet formation dynamics of viscoelastic, polymer solutions with FB, for applications in large-scale synthesis of materialsMinisterio de Economía, Industria y Competitividad DPI2016-78887-C3-1-
Two new species of terrestrial frogs of the Pristimantis gladiator complex (Anura, Strabomantidae) from the Ecuadorian Andes, with insights on their biogeography and skull morphology
The explosive diversity of rainfrogs (Pristimantis spp) reaches its highest levels in the mountains of the Tropical Andes, with remarkable cryptic species mainly in unexplored areas of Ecuador. Based on phylogenetics, morphometric traits, skull osteology and bioacoustics, we describe two new species of Pristimantis, previously confused with Pristimantis gladiator, that belong to the subgenus Trachyphrynus traditionally known as the Pristimantis myersi species group. The two new taxa are closely related, but have allopatric distributions. We discuss the importance of the Quijos and Pastaza River valleys in the diversification along Amazonian slopes of the Ecuadorian Andes
Assessment of Fear of COVID-19 in Older Adults: Validation of the Fear of COVID-19 Scale
There is no information in Peru on the prevalence of mental health problems associated with COVID-19 in older adults. In this sense, the aim of the study was to gather evidence on the factor structure, criterion-related validity, and reliability of the Spanish version of the Fear of COVID-19 Scale (FCV-19S) in this population. The participants were 400 older adults (mean age = 68.04, SD = 6.41), who were administered the Fear of COVID-19 Scale, Revised Mental Health Inventory-5, Patient Health Questionnaire-2 items, and Generalized Anxiety Disorder Scale 2 items. Structural equation models were estimated, specifically confirmatory factor analysis (CFA), bifactor CFA, and structural models with latent variables (SEM). Internal consistency was estimated with composite reliability indexes (CRI) and omega coefficients. A bifactor model with both a general factor underlying all items plus a specific factor underlying items 1, 2, 4, and 5 representing the emotional response to COVID better represents the factor structure of the scale. This structure had adequate fit and good reliability, and additionally fear of COVID had a large effect on mental health. In general, women had more fear than men, having more information on COVID was associated to more fear, while having family or friends affected by COVID did not related to fear of the virus. The Spanish version of the Fear of COVID-19 Scale presents evidence of validity and reliability to assess fear of COVID-19 in the Peruvian older adult population
Diversification of Aeonium Species Across Macaronesian Archipelagos: Correlations Between Genome-Size Variation and Their Conservation Status
The rich endemic flora of the Macaronesian Islands places these oceanic archipelagos
among the top biodiversity hotspots worldwide. The radiations that have determined the
evolution of many of these insular lineages resulted in a wealth of endemic species, many
of which occur in a wide range of ecological niches, but show small distribution areas in
each of them. Aeonium (Crassulaceae) is the most speciose lineage in the Canary Islands
(ca. 40 taxa), and as such can be considered a good model system to understand the
diversification dynamics of oceanic endemic floras. The present study aims to assess the
genome size variation within Aeonium distribution, i.e., the Macaronesian archipelagos
of Madeira, Canaries and Cabo Verde, and analyse it together with information
on distribution (i.e., geography and conservation status), taxonomy (i.e., sections),
morphological traits (i.e., growth-form), geological data (i.e., island’s geological age),
and environmental variables (i.e., altitude, annual mean temperature, and precipitation).
Based on extensive fieldwork, a cytogeographic screening of 24 Aeonium species was
performed. The conservation status of these species was assessed based on IUCN
criteria. 61% of the taxa were found to be threatened (4% Endangered and 57%
Vulnerable). For the first time, the genome size of a comprehensive sample of Aeonium
across the Macaronesian archipelagos was estimated, and considerable differences in
Cx-values were found, ranging from0.984 pg (A. dodrantale) to 2.768 pg (A. gorgoneum).
An overall positive correlation between genome size and conservation status was found,
with the more endangered species having the larger genomes on average. However,
only slight relationships were found between genome size, morphological traits, and environmental variables. These results underscore the importance of characterizing the
cytogenomic diversity and conservation status of endemic plants found in Macaronesian
Islands, providing, therefore, new data to establish conservation priorities.info:eu-repo/semantics/publishedVersio
Covariate effects of resting heart rate variability on affective ratings and startle reflex during cognitive reappraisal of negative emotions
Heart Rate Variability (HRV) has been widely studied in laboratory settings due to its clinical implications, primarily as a potential biomarker of emotion regulation (ER). Studies have reported that individuals with higher resting HRV show more distinct startle reflexes to negative stimuli as compared to those with lower HRV. These responses have been associated with better defense system function when managing the context demands. There is, however, a lack of empirical evidence on the association between resting HRV and eyeblinks during laboratory tasks using instructed ER. This study explored the influence of tonic HRV on voluntary cognitive reappraisal through subjective and startle responses measured during an independent ER task. In total, 122 healthy participants completed a task consisting of attempts to upregulate, downregulate, or react naturally to emotions prompted by unpleasant pictures. Tonic HRV was measured for 5 minutes before the experiment began. Current results did not support the idea that self-reported and eyeblink responses were influenced by resting HRV. These findings suggest that, irrespective of resting HRV, individuals may benefit from strategies such as reappraisal that are useful for managing negative emotions. Experimental studies should further explore the role of individual differences when using ER strategies during laboratory task
Meroterpenoids from the Brown Alga Cystoseira usneoides as Potential Anti-Inflammatory and Lung Anticancer Agents
The anti-inflammatory and anticancer properties of eight meroterpenoids isolated from the brown seaweed Cystoseira usneoides have been evaluated. The algal meroterpenoids (AMTs) 1-8 were tested for their inhibitory effects on the production of the pro-inflammatory cytokines tumor necrosis factor (TNF-alpha), interleukin-6 (IL-6), and interleukin-1 beta (IL-1 beta), and the expression of cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) in LPS-stimulated THP-1 human macrophages. The anticancer effects were assessed by cytotoxicity assays against human lung adenocarcinoma A549 cells and normal lung fibroblastic MRC-5 cells, together with flow cytometry analysis of the effects of these AMTs on different phases of the cell cycle. The AMTs 1-8 significantly reduced the production of TNF-alpha, IL-6, and IL-1 beta, and suppressed the COX-2 and iNOS expression, in LPS-stimulated cells (p < 0.05). The AMTs 1-8 displayed higher cytotoxic activities against A549 cancer cells than against MRC-5 normal lung cells. Cell cycle analyses indicated that most of the AMTs caused the arrest of A549 cells at the G2/M and S phases. The AMTs 2 and 5 stand out by combining significant anti-inflammatory and anticancer activities, while 3 and 4 showed interesting selective anticancer effects. These findings suggest that the AMTs produced by C. usneoides may have therapeutic potential in inflammatory diseases and lung cancer
How to use mixed precision in ocean models : Exploring a potential reduction of numerical precision in NEMO 4.0 and ROMS 3.6
ceived funding from the EU ESiWACE H2020 Framework Programme under grant agreement no. 823988, from the Severo Ochoa (SEV-2011-00067) program of the Spanish Government and from the Ministerio de Economia y Competitividad under contract TIN2017-84553-C2-1-R.Mixed-precision approaches can provide substantial speed-ups for both computing- and memory-bound codes with little effort. Most scientific codes have overengineered the numerical precision, leading to a situation in which models are using more resources than required without knowing where they are required and where they are not. Consequently, it is possible to improve computational performance by establishing a more appropriate choice of precision. The only input that is needed is a method to determine which real variables can be represented with fewer bits without affecting the accuracy of the results. This paper presents a novel method that enables modern and legacy codes to benefit from a reduction of the precision of certain variables without sacrificing accuracy. It consists of a simple idea: we reduce the precision of a group of variables and measure how it affects the outputs. Then we can evaluate the level of precision that they truly need. Modifying and recompiling the code for each case that has to be evaluated would require a prohibitive amount of effort. Instead, the method presented in this paper relies on the use of a tool called a reduced-precision emulator (RPE) that can significantly streamline the process. Using the RPE and a list of parameters containing the precisions that will be used for each real variable in the code, it is possible within a single binary to emulate the effect on the outputs of a specific choice of precision. When we are able to emulate the effects of reduced precision, we can proceed with the design of the tests that will give us knowledge of the sensitivity of the model variables regarding their numerical precision. The number of possible combinations is prohibitively large and therefore impossible to explore. The alternative of performing a screening of the variables individually can provide certain insight about the required precision of variables, but, on the other hand, other complex interactions that involve several variables may remain hidden. Instead, we use a divide-and-conquer algorithm that identifies the parts that require high precision and establishes a set of variables that can handle reduced precision. This method has been tested using two state-of-the-art ocean models, the Nucleus for European Modelling of the Ocean (NEMO) and the Regional Ocean Modeling System (ROMS), with very promising results. Obtaining this information is crucial to build an actual mixed-precision version of the code in the next phase that will bring the promised performance benefits
Detection of Atrial Fibrillation Driver Locations Using CNN and Body Surface Potentials
[EN] Atrial fibrillation (AF) is characterized by complex and
irregular propagation patterns, and AF onset locations
and drivers responsible for its perpetuation are main targets for ablation procedures. Several Deep Learningbased methods have proposed to detect AF, but the estimation of the atrial area where the drivers are found is a topic
where further research is needed. In this work, we propose
to estimate the zone where AF drivers are found from body
surface potentials (BSPs) and Convolutional Neural Networks (CNN), modeling a supervised classification problem. Accuracy in the test set was 0.89 when using noisy
BSPs (SNR=20dB), while the Cohen¿s Kappa was 0.85.
Therefore, the proposed method could help to identify target regions for ablation using a non-invasive procedure,
and avoiding the use of ECG Imaging (ECGI).This work has been partially supported by: Ministerio de Ciencia e Innovacion (PID2019-105032GB-I00),
Instituto de Salud Carlos III, and Ministerio de Ciencia, Innovacion y Universidades (supported by FEDER
Fondo Europeo de Desarrollo Regional PI17/01106 and
RYC2018-024346B-750), Consejeria de Ciencia, Universidades e Innovacion of the Comunidad de Madrid through
the program RIS3 (S-2020/L2-622), EIT Health (Activity
code 19600, EIT Health is supported by EIT, a body of
the European Union) and the European Union's Horizon
2020 research and innovation program under the Marie
Skodowska-Curie grant agreement No. 860974.Cámara-Vázquez, MÁ.; Hernández-Romero, I.; Morgado-Reyes, E.; Guillem Sánchez, MS.; Climent, AM.; Barquero-Pérez, Ó. (2021). Detection of Atrial Fibrillation Driver Locations Using CNN and Body Surface Potentials. 1-4. https://doi.org/10.22489/CinC.2021.2561
Entropy based parametrization of soils: Models and Tools
Particle-size distribution (PSD) is a fundamental soil physical property. The PSD is commonly reported in terms of the mass percentages of sand, silt and clay present
Factors controlling rare earth element plus yttrium enrichment in Fe–Mn crusts from Canary Islands Seamounts (NE Central Atlantic)
Marine minerals are important because concentrate in their structure high contents of strategic and critical elements as rare earth elements. Forty-two samples from eight seamounts of Canary Islands Seamount Province (CISP) have been analyzed in order to evaluate their rare earth elements plus yttrium contents (REY). Highest contents of REY are related to hydrogenetic minerals and essentially Fe-vernadite (on average 3000 μg/g). Diagenetic minerals, on the other hand, show the lowest REY contents with an average content of 260 μg/g. These differences also depend on the growth rates, hydrogenetic minerals with growth rates between 0.5 and 5 mm/Ma allow the incorporation of more REY in their structure. REY contents in studied samples varies depending several factors associated with depth and location, shallowest samples presumably growth near or within the oxygen minimum zone are the most enriched with up to 3800 μg/g due to local enrichment of these elements and the slowest growth rate promoted by the reduced ambient conditions while deeper samples around 3000 m water depth show 2800 μg/g. Location also has a role in REY contents essentially due to the presence of different currents. Samples faced to north are exposed to the more oxygenated waters of the North Atlantic Deep Water and are depleted in REY if compared with deeper samples facing to south to the more oxic Antarctic Bottom Water. Finally, the case of study made on three different seamounts of the CISP show that Fe–Mn crusts from this area could provide on average 130 tons of hydrometallurgical recovered REY (based on 1 km2 areal crust coverage) together with interesting quantity of several other strategic and base elements as Mn, Co, Ni, Cu, V, Mo between others
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