1,783 research outputs found
Applied ecology of fear: A meta-analysis on the potential of facilitating human-wildlife coexistence through nonlethal tools
The term “applied ecology of fear” was recently introduced to describe the growing research field that applies the theory of the ecology of fear to manage wildlife behaviour. The management goal is to drive targeted species spatially and temporally away from areas of human interest by inducing cues from real or simulated predators to reduce human-wildlife conflict.We aimed to quantify, through a meta-analysis, if prey anti-predator response would vary among field trials versus pen-based studies, predator cue types, predator hunting style and prey feeding type, and be stronger in response to larger predators relative to the prey's size. We also explored what studies found in terms of wildlife habituation to cues.We used species belonging to the Cervidae family as a case study since deer are among the group of species with the highest degree of human-wildlife conflict. We retrieved 114 studies from online databases and collected information from 39 of those studies that fitted our research scope.We found that acoustic cues more frequently led to an anti-predator response in deer than olfactory or visual cues. Neither predator hunting strategy nor deer feeding strategy or type of study (free-ranging or pen-based animals) influenced the extent to which deer responded to cues. Deer more frequently responded to cues that belonged to a larger predator relative to their size. Habituation was reported in less than one-third of the studies, with a study period ranging from 1 to 90 days, and occurred as soon as 7 days after the start of the study on average.Our meta-analysis suggested that acoustic cues hold most potential as a tool to manage deer behaviour. These findings support the development of applied ecology of fear tools that introduce predator cues to reduce human-wildlife conflicts. Major knowledge gaps remain that limit the effective use of such tools in wildlife management and future research should focus on improving our understanding of habituation to cues, on comparing the effectiveness of different types of cues, on simultaneously using a combination of cue types, and on testing cues at spatial–temporal scales of actual land-uses
Crecimiento de cristales en presencia de impurezas de diferente forma y tamaño
En este trabajo nosotros presentamos un nuevo modelo cinético tendiente a describir el crecimiento de cristales a partir de una solución acuosa y en presencia de impurezas. Dicho modelo es desarrollado a partir de una generalización de la aproximación propuesta por Davey y Mullin 1. El nuevo marco teórico combina (i) una expresión analítica para la velocidad de crecimiento del cristal, donde la misma disminuye linealmente al aumentar el cubrimiento (θeq) de impurezas adsorbidas, y (ii) una nueva ecuación de isoterma de adsorción (θeq como función de la concentración de impurezas CI) en la que el adsorbato puede ocupar más de un sitio de adsorción (impureza estructurada). Este formalismo permite obtener una isoterma exacta de adsorción de impurezas lineales en una dimensión, y proporciona una buena aproximación para un sistema bidimensional de múltiple ocupación de sitios, incorporando así dos factores muy importantes (tamaño y forma) que determinan las características de inhibición del crecimiento del cristal por parte de una impureza. Los datos de la teoría fueron comparados con simulaciones de Monte Carlo. Además, los resultados teóricos fueron aplicados a datos experimentales de velocidades relativas de crecimiento de cristales de KBr en presencia de impurezas (ácidos carboxílicos alifáticos) de diferentes tamaños: HCOOH, CH3COOH, C2H5COOH y C3H7COOH. Un buen acuerdo entre teoría, simulaciones y experimentos fue encontrado. El modelo teórico aquí propuesto es simple, con parámetros que tienen un significado físico preciso. Estos parámetros se pueden obtener a partir de experimentos termodinámicos y se relacionan directamente con la configuración espacial de las moléculas de impurezas en el estado adsorbido. En este sentido, es importante enfatizar la diferencia con la teoría de Kubota y Mullin 2, donde la presencia de un parámetro empírico (factor de efectividad ) es necesaria para interpretar datos análogos a los analizados aquí.Fil: López Ortiz, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Quiroga, Evelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Narambuena, Claudio Fabian. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Grupo Vinculado Bionanotecnología y Sistemas Complejos | Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Grupo Vinculado Bionanotecnología y Sistemas Complejos. - Universidad Tecnológica Nacional. Facultad Regional San Rafael. Grupo Vinculado Bionanotecnología y Sistemas Complejos; ArgentinaFil: Ramirez Pastor, Antonio Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaVIII Encuentro de Física y Química de SuperficiesSan LuisArgentinaUniversidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés ZgrablichUniversidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de MatemáticaUniversidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Químic
Thermal hysteresis activity of antifreeze proteins: A model based on fractional statistics theory of adsorption
Antifreeze proteins (AFPs) adsorb to the surface of embryonic ice crystals to prevent their growth. The protein-ice adsorption lowers the freezing point of the solution. Then, a thermal hysteresis can be defined as the difference between the melting and freezing temperatures. This quantity is a measure of the antifreeze protein activity. In this sense, there exists evidence that the antifreeze activity enhances with increasing the area/length of the ice-binding sites. In order to interpret this thermal hysteresis behavior, we introduce a two-dimensional adsorption model based on fractional statistics theory. The analytical expressions are obtained in terms of an exclusion parameter, which depend on the structure of the protein and area of the ice-binding sites. By using the model, thermal hysteresis activity is calculated for AFPs of different size, shape and number of active sites. The theoretical results show a good qualitative agreement with reported experimental data in the literature.Fil: López Ortiz, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Quiroga, Evelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Narambuena, Claudio Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina. Universidad Tecnologica Nacional. Facultad Regional San Rafael; ArgentinaFil: Riccardo, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Ramirez Pastor, Antonio Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentin
Sexual and Reproductive Health for Young Adults in Colombia: Teleconsultation Using Mobile Devices
Background: Sexual risk behaviors associated with poor information on sexuality have contributed to major public health problems in the area of sexual and reproductive health in teenagers and young adults in Colombia.
Objective: To report our experience with the use of DoctorChat Mobile to provide sexual education and information among university students in Bogota, Colombia, and knowledge about the sexual risk factors detected among them.
Methods: A mobile app that allows patients to ask about sexual and reproductive health issues was developed. Sexual and reproductive risk behaviors in a sample of young adults were measured before and after the use of the app through the validated survey Family Health International (FHI) Behavioral Surveillance Survey (BSS) for Use With Adults Between 15 and 49 Years. A nonprobabilistic convenience recruitment was undertaken through the study´s webpage. After completing the first survey, participants were allowed to download and use the app for a 6-month period (intervention), followed by completion of the same survey once again. For the inferential analysis, data was divided into 3 groups (dichotomous data, discrete quantitative data, and ordinal data) to compare the results of the questions between the first and the second survey. The study was carried out with a sample of university students between 18 and 29 years with access to mobile phones. Participation in the study was voluntary and anonymous.
Results: A total of 257 subjects met the selection criteria. The preintervention survey was answered by 232 subjects, and 127 of them fully answered the postintervention survey. In total, 54.3% (69/127) of the subjects completed the survey but did not use the app, leaving an effective population of 58 subjects for analysis. Of these subjects, 53% (31/58) were women and 47% (27/58) were men. The mean age was 21 years, ranging between 18 and 29 years. The differences between the answers from both surveys were not statistically significant. The main sexual risk behaviors identified in the population were homosexual intercourse, nonuse of condoms, sexual intercourse with nonregular and commercial partners, the use of psychoactive substances, and lack of knowledge on symptoms of sexually transmitted diseases and HIV transmission.
Conclusions: Although there were no differences between the pre- and postintervention results, the study revealed different risk behaviors among the participating subjects. These findings highlight the importance of promoting high-impact educational strategies on this matter and the importance of providing teenagers and young adults with easily accessible tools with reliable health information, regardless of their socioeconomic status
Regulator of calcineurin 1 (Rcan1) has a protective role in brain ischemia/reperfusion injury
<p>Abstract</p> <p>Background</p> <p>An increase in intracellular calcium concentration [Ca<sup>2+</sup>]<sub>i </sub>is one of the first events to take place after brain ischemia. A key [Ca<sup>2+</sup>]<sub>i</sub>-regulated signaling molecule is the phosphatase calcineurin (CN), which plays important roles in the modulation of inflammatory cascades. Here, we have analyzed the role of endogenous regulator of CN 1 (Rcan1) in response to experimental ischemic stroke induced by middle cerebral artery occlusion.</p> <p>Methods</p> <p>Animals were subjected to focal cerebral ischemia with reperfusion. To assess the role of Rcan1 after stroke, we measured infarct volume after 48 h of reperfusion in <it>Rcan1 </it>knockout (KO) and wild-type (WT) mice. <it>In vitro </it>studies were performed in astrocyte-enriched cortical primary cultures subjected to 3% oxygen (hypoxia) and glucose deprivation (HGD). Adenoviral vectors were used to analyze the effect of overexpression of Rcan1-4 protein. Protein expression was examined by immunohistochemistry and immunoblotting and expression of mRNA by quantitative real-time Reverse-Transcription Polymerase Chain Reaction (real time qRT-PCR).</p> <p>Results</p> <p>Brain ischemia/reperfusion (I/R) injury <it>in vivo </it>increased mRNA and protein expression of the calcium-inducible Rcan1 isoform (Rcan1-4). I/R-inducible expression of Rcan1 protein occurred mainly in astroglial cells, and in an <it>in vitro </it>model of ischemia, HGD treatment of primary murine astrocyte cultures induced Rcan1-4 mRNA and protein expression. Exogenous Rcan1-4 overexpression inhibited production of the inflammatory marker cyclo-oxygenase 2. Mice lacking Rcan1 had higher expression of inflammation associated genes, resulting in larger infarct volumes.</p> <p>Conclusions</p> <p>Our results support a protective role for Rcan1 during the inflammatory response to stroke, and underline the importance of the glial compartment in the inflammatory reaction that takes place after ischemia. Improved understanding of non-neuronal mechanisms in ischemic injury promises novel approaches to the treatment of acute ischemic stroke.</p
Ileal apparent and standardized amino acid digestibility of soybean and colza meal in diets for finishing pigs
Agri-food chains generate by-products such as soybean and colza meal for animal feed. Their nutritional value is variable and should be analysed for better quality control before their inclusion in balanced diets. The objective was to determine the content and ileal apparent and standardized digestibility of protein and amino acids (AA) of soybean (PS) and colza meal (PC) as a source of protein in diets for finishing pigs. The experimental units were arranged in a 3×3 Latin square design repeated. The treatments (T) were T1: PS+corn starch, T2: PC+corn starch, and T3: corn starch (Control), which were randomly assigned to six pigs cannulated in distal ileum (PV 75±1.2 kg). The variables were contents and apparent ileal and standardized ileal digestibility of amino acids in soybean and colza meal. To determine digestibility, chromic oxide was added to the diets. The protein and fat contents were higher in the soybean meal. Ash, crude fibre, neutral detergent fibre, acid detergent fibre, phosphorus and calcium contents were higher in the colza meal. Essential amino acid content was higher in soybean meal, but methionine was higher in colza meal. Apparent ileal digestibility (DIA) of total amino acids was similar (p > 0.05) among protein ingredients; but for lysine and threonine it was higher (p ≤ 0.05) in soybean meal, except methionine. Methionine DIA was 89.78 %, 3.88 % higher (p ≤ 0.05) in colza meal. Standardized ileal digestibility (DIE) of total amino acids was similar (p > 0.05) among ingredients, but lysine and threonine were higher (p ≤ 0.05) in soybean meal. DIE was different (p ≤ 0.05) among ingredients for all amino acids except methionine. Ileal and standardized digestibility of all amino acids were higher in soybean meal, except methionine, which was higher in colza meal. The DIA of total amino acids was similar in both protein ingredients, except lysine and threonine in soybean meal and methionine in colza meal
A pre-correlation RFI mitigation algorithm for L-band interferometric radiometers
Radio Frequency Interference (RFI) is a major concern for both real and synthetic aperture radiometers. After the lessons learnt from SMOS, ESA is preparing the next generation of L-band interferometric radiometers with RFI mitigation integrated into the cross-correlators. This work presents a preliminary design and results of a pre-correlation RFI mitigation algorithm tailored for interferometric radiometers. The results show that the correlation error introduced by the RFI is reduced on average to the half, with peaks of 20 dB of mitigation.Peer ReviewedPostprint (author's final draft
RFI detection and mitigation for advanced correlators in interferometric radiometers
This work presents the first RFI detection and mitigation algorithm for the interferometric radiometers that will be implemented in its correlator unit. The algorithm operates in the time and frequency domains, applying polarimetric and statistical tests in both domains, and exhibiting a tunable and arbitrary low probability of false alarm. It is scalable to a configurable number of receivers, and it is optimized in terms of quantization bits and the implementation of the cross-correlations in the time or frequency domains for hardware resource saving. New features of this algorithm are the computation of the Stokes parameters per frequency bin in the Short-Time Fourier Transform and a new parameter called Polarimetric Kurtosis. If RFI is detected in one domain or in both, it is removed using the calculated blanking masks. The optimum algorithm parameters are computed, such as length of the FFTs, the threshold selection for a given probability of false alarm, and the selection of the blanking masks. Last, an important result refers to the application of Parseval’s theorem for the computation of the cross-correlations in the frequency domain, instead of in the time domain, which is more efficient and leads to smaller errors even when using moderate quantization levels. The algorithm has been developed in the framework of the ESA’s technology preparation for a potential L-band radiometer mission beyond SMOS. However, it is also applicable to (polarimetric) real aperture radiometers, and its performance would improve if more than one bit is used in the signal quantization.This research was funded by ESA, grant number ITT AO9359, by project SPOT: Sensing with
Pioneering Opportunistic Techniques grant RTI2018-099008-B-C21/AEI/10.13039/501100011033, and
the grant for recruitment of early stage research staff of the Agència de Gestió d’Ajuts Universitaris i
de Recerca (AGAUR) Generalitat de Catalunya, Spain (FISDUR2020/105).Peer ReviewedPostprint (published version
Sensores para el monitoreo de corrosión en hormigón armado: Desarrollo y aplicabilidad
El Departamento de Corrosión de la Comisión Nacional de Energía Atómica (CNEA) mantiene un programa de desarrollo de sensores para el monitoreo de la corrosión en estructuras de hormigón armado. En el marco del Programa Nacional de Gestión de Residuos Radioactivos (PNGRR), se desarrolla instrumentación que permite monitorear el avance de la corrosión en elementos estructurales de hormigón armado de alta durabilidad (> 300 años), a la vez que colabora con la prueba de desempeño ante la corrosión de hormigones estructurales especiales. En la actualidad, el grupo de corrosión en hormigón armado mantiene programas de monitoreo de estructuras civiles, asociadas a la industria energética nuclear y no nuclear, utilizando sensores desarrollados íntegramente por el grupo. En este documento se presenta la descripción de los sensores desarrollados a la actualidad, su funcionamiento y su aplicabilidad como instrumento de monitoreo e investigación. A su vez, se hace referencia al desarrollo de nueva tecnología para la actualización de los sensores.The Corrosion Department of the National Atomic Energy Commission (CNEA) has a sensor development program for monitoring corrosion in reinforced concrete structures. In the context of the National Radioactive Waste Management Program (PNGRR), instrumentation is developed to monitor the progress of corrosion in high durability reinforced concrete structural elements (> 300 years), while collaborating with performance tests against corrosion of special structural concretes. At present, the reinforced concrete corrosion group has monitoring programs for civil structures, associated with the nuclear and non-nuclear energy industry, using sensors developed entirely by the group. This document presents the description of the sensors currently developed, their operation and their applicability as a monitoring and research instrument. In turn, reference is made to the development of new technology for updating sensors.Fil: Gomez, Enzo David. Comisión Nacional de Energía Atómica. Gerencia D/area de Energía Nuclear. Gerencia Materiales. Departamento Corrosión; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Carricondo, Juan Ignacio. Comisión Nacional de Energía Atómica. Gerencia D/area de Energía Nuclear. Gerencia Materiales. Departamento Corrosión; Argentina. Universidad Nacional de San Martín; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Torres Ramirez, Jhon Edisson. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Unidad de Actividad de Materiales (CAC); ArgentinaFil: Vazquez, Damián René. Comisión Nacional de Energía Atómica. Gerencia D/area de Energía Nuclear. Gerencia Materiales. Departamento Corrosión; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Farina, Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia D/area de Energía Nuclear. Gerencia Materiales. Departamento Corrosión; Argentina. Universidad Nacional de San Martín; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Duffó, Gustavo Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia D/area de Energía Nuclear. Gerencia Materiales. Departamento Corrosión; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín; Argentin
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