Effects of landscape fragmentation on bird communities in a tropical hotspot

Changes in land-use such as agricultural expansion and urbanization lead to landscape fragmentation among the Tropical Andes. This region also has exceptionally high levels of biodiversity and endemism; hence, it has become a priority for conservation efforts. Ecuador is part of Tropical Andes and in the Ecuadorian high-altitude Andes habitat loss is already widespread and persistent. A representative area for Andean avifauna is Cajas National Park. The park is located in the southern Andes of Ecuador and is the only protected area in the south-western Andes. The park is characterized by containing 90% páramo grassland ecosystem which surrounds > 1000 patches of Polylepis woodland. Despite its importance for bird conservation and its protected status, the Cajas National Park suffers from several stressors, which are modifying the natural habitat characteristics of both páramo grassland and Polylepis patches. We tested the effect of roads (as a major stressor), habitat structure and vegetation composition of both the páramo matrix and the Polylepis patches on the bird community. We found the habitat-specialized birds such as shrubby páramo birds had reduced abundance at the roadsides due to habitat modification led by the introduction of non-native plants. This same condition drives further change in community composition with generalist and a few páramo specialists being found within the area influenced by the road. Our findings also confirm the importance of natural heterogeneity of páramo grassland and the quality of small and medium-sized patches of Polylepis forest. For instance, there is a positive relationship of Polylepis specialist movement (between patch and matrix) with an increase in the proportion of woody plants. Furthermore, Polylepis patches located in higher altitude increased the centrality index of Polylepis specialists. The loss of specialized birds in disturbed areas and also the positive effect of Polylepis quality and páramo heterogeneity are crucial to a better understanding of the dynamics in the high-altitude Andes. Here, there is a vital importance to take on a landscape view, where not only large Polylepis patches are considered vital for avian conservation. Furthermore, human activities in the páramo landscape may reduce the natural habitat heterogeneity with a negative influence on biodiversity patterns. Several protected areas in Ecuador include large areas of páramo ecosystem and all of them are highly threatened; to promote effective nature conservation it is imperative to develop conservation plans that take habitat heterogeneity into account both in Ecuador and throughout the Andean region

Optical and Near-Infrared Radial Velocity Content of M Dwarfs: Testing Models with Barnard's Star

High precision radial velocity (RV) measurements have been central in the study of exoplanets during the last two decades, from the early discovery of hot Jupiters, to the recent mass measurements of Earth-sized planets uncovered by transit surveys. While optical radial-velocity is now a mature field, there is currently a strong effort to push the technique into the near-infrared (nIR) domain (chiefly $Y$, $J$, $H$ and $K$ band passes) to probe planetary systems around late-type stars. The combined lower mass and luminosity of M dwarfs leads to an increased reflex RV signal for planets in the habitable zone compared to Sun-like stars. The estimates on the detectability of planets rely on various instrumental characteristics, but also on a prior knowledge of the stellar spectrum. While the overall properties of M dwarf spectra have been extensively tested against observations, the same is not true for their detailed line profiles, which leads to significant uncertainties when converting a given signal-to-noise ratio to a corresponding RV precision as attainable on a given spectrograph. By combining archival CRIRES and HARPS data with ESPaDOnS data of Barnard's star, we show that state-of-the-art atmosphere models over-predict the $Y$ and $J$-band RV content by more than a factor of $\sim$$2$, while under-predicting the $H$ and $K$-band content by half.Comment: accepted for publication in A

Telluric-line subtraction in high-accuracy velocimetry: a PCA-based approach

Optical velocimetry has led to the detection of more than 500 planets to date and there is a strong effort to push m/s velocimetry to the near-infrared to access cooler and lighter stars. The presence of numerous telluric absorption lines in the nIR brings an important challenge. As the star's barycentric velocity varies through the year, the telluric absorption lines effectively varies in velocity relative to the star's spectrum by the same amount leading to important systematic RV offsets. We present a novel principal component analysis-based approach for telluric line subtraction and demonstrated its effectiveness with archival HARPS data for GJ436 and {\tau} Ceti, over parts of the R-band that contain strong telluric absorption lines. The main results are: 1) a better RV accuracy with excluding only a few percentage of the domain, 2) better use of the entire spectrum to measure RV and 3) a higher telescope time efficency by using A0V telluric standard from telescope archive.Comment: Presented at SPIE Astronomical Telescopes + Instrumentation 201

Modelación y análisis por desempeño de una estructura de acero, considerando deterioro para la predicción del colapso

En materia sísmica, los códigos de diseño manejan el concepto de transformar los complicados comportamientos dinámicos no lineales de estructuras ante sismos en problemas lineales equivalentes a más de la asignación de coeficientes arbitrarios de reducción de carga. En este trabajo de titulación se propone el análisis por desempeño a nivel de derivas de un sistema especial sismorresistente de acero, en base a análisis dinámicos no lineales. También se muestra la ejecución de una serie de chequeos a través de análisis estáticos y dinámicos no lineales para verificar el correcto comportamiento del modelo. Los análisis se realizarán en el software OpenSees. El prototipo a utilizar proviene de un ejemplo de evaluación de colapso usado en el proyecto ATC-76-1. El modelo generado es de plasticidad concentrada, con rótulas plásticas en vigas y columnas, siguiendo la teoría de deterioro modificada de Ibarra-Medina-Krawinkler. La no linealidad geométrica, efecto PDelta, se incluye a través de la modelación de una columna sin resistencia lateral, leaning column. Se analizaron tres niveles de intensidad sísmica (servicio, diseño y MCE), sobre el modelo calibrado con dos estrategias de reducción de capacidad por la interacción de la carga axial – momento. Los resultados muestran que los objetivos de servicio no se cumplen mientras que los objetivos del diseño si satisfacen los requisitos de derivas. Para la intensidad MCE se hace más evidente el efecto de la reducción de capacidad, cumpliendo los requisitos de desempeño únicamente para la estrategia 2 (carga axial debido a cargas de gravedad).In seismic design, codes handle the concept of transforming complicated nonlinear dynamical behaviors of structures during earthquakes into equivalent linear problems, even assigning arbitrary load reduction coefficients for analysis. In this work, the performance analysis at drift level of a special seismic steel system is proposed, based on non-linear dynamic analyzes. It also shows the execution of a series of checks through nonlinear dynamic and static analysis to verify the correct behavior of the model. The analyzes will be carried out in OpenSees. The prototype to be used comes from an example of collapse evaluation used in the ATC-76-1 project. The model generated has concentrated plasticity, with plastic hinges in beams and columns, following the modified deterioration theory of Ibarra-Medina-Krawinkler. The geometric non-linearity, PDelta effect, is included through modeling a column without lateral resistance, leaning column, loaded with the weight of the non-tributary area of the lateral system. Three levels of seismic intensity were analyzed, corresponding to earthquakes with return periods of 72, 475 and 2500 years (service, design and MCE), on the model calibrated with two capacity reduction strategies by the interaction of the axial load - moment. The results show that the service objectives are not met while the design objectives do meet the requirements of drifts. For the MCE intensity the effect of the capacity reduction is more evident, fulfilling the performance requirements only for strategy 2 (axial load due to gravity loads).Ingeniero CivilCuenc

Occurrence and antimicrobial susceptibility of thermophilic Campylobacter species isolated from healthy children attending municipal care centers in Southern Ecuador

The prevalence and antimicrobial susceptibility of Campylobacter jejuni and C. coli strains in healthy, well-nourished children of middle socioeconomic level from Southern Ecuador were determined. Among the 127 children studied, 17 (13.4%) harbored Campylobacter sp. corresponding to C. jejuni (7.1%) and C. coli (6.3%) with a higher concentration of C. jejuni among boys (8.6%) and C. coli (8.8%) among girls. C. jejuni showed high resistance to nalidixic acid and ciprofloxacin (77.8%), but susceptibility to all other antimicrobials tested. C. coli strains showed resistance to more antibiotics than C. jejuni strains including resistance to nalidixic acid (75%), ciprofloxacin (75%), erythromycin (12.5%) and ampicillin (28.6), but susceptible to gentamicin and amoxicillin/clavulanic acid

Manejo quirúrgico del síndrome Crouzon con osteotomías Le Fort III y avance fronto orbitario asistido por neuronavegación : caso clínico

Objetives: Crouzon syndrome manifests as an autosomal dominant disease, which manifests with craniosynostosis, exophthalmos, middle third hypoplasia, mandibular pseudoprognathism within the main features which can cause alterations such as amaurosis, strabismus, obstructive apnea, dysphonia, the initial manifestations be critically dependent on craniosynostosis, so it should be treated as emergency surgery at an early age and avoid compromises damaging to brain structures...Objetivos: El síndrome Crouzon se manifiesta como una enfermedad autosómica dominante, que manifiesta con craneosinostosis, exoftalmos, hipoplasia de tercio medio, pseudoprognatismo mandibular dentro de las características principales las cuales pueden causar alteraciones como amaurosis, estrabismo, apnea obstructiva, disfonía, las manifestaciones iniciales pueden ser criticas dependientes de la craneosinostosis, por lo que debe ser tratada como cirugía de emergencia a edades tempranas y evitar compromisos lesivos a estructuras del encéfalo, esta cirugía consiste en realizar osteotomías que permitan la liberación de la presión intracraneal..

Ataques Zero-day: Despliegue y evolución

In cybersecurity and computer science, the term “zero-day” is commonly related to troubles, threats, and hazards due to the lack of knowledge, experience, or misunderstanding. A zero-day attack is generally considered a new vulnerability with no defense; thus, the possible attack will have a highrisk probability, and a critical impact.  Unfortunately, only a few surveys on the topic are available that would help understand these threats, which are not enough to construct new solutions to detect, prevent, and mitigate them. In this paper, it is conducted a review of the zero-day attack, how to understand its real impact, and a few different accessible solutions nowadays. This study introduces a useful reference that provides researchers with knowledge to understand the current problem concerning zero- days attacks; hence they could develop solutions for facing them.En la ciberseguridad y la informática, el término "Zero-day" se relaciona comúnmente con problemas, amenazas y peligros, esto debido a la falta de conocimiento, experiencia o malentendidos relacionados. Un ataque de Zero-day se considera generalmente una nueva vulnerabilidad sin defensa; por lo tanto, el ataque consecuente tendrá una alta probabilidad de riesgo, y un impacto crítico. Lamentablemente, sólo unos pocos estudios están  disponibles  para  comprender  estas  amenazas, y no bastan para construir nuevas soluciones para detectar, prevenir y mitigar estas dificultades. En este artículo, se presenta una revisión del ataque Zero-day, enfocándose en comprender su impacto real y algunas soluciones accesibles  hoy  en  día. Este estudio presenta una referencia útil que proporciona a los investigadores conocimientos para comprender el problema actual relacionado con los ataques Zero-day. Este puede ser un punto de partida para desarrollar soluciones para combatir este problema

Acoustic abundance estimation of Sardine (Sardina pilchardus Walb) off Cantabric and Galician waters August 1985

Results of the anual acoustic survey of sardine present off Cantabric and Galician coast in August 1985 are reported. Estimations of the total biomass, abundance by age groups and the strength of 1985 year class were obtained. The total biomass estimation was 149.000 tons.On presente ici les resultats de la campagne acoustique sur la sardine au large des côtes Cantabrique et Galicienne dans Aôut 1985. On a obtenu estimations de la biomasse total, l'abondance para classe d'áge et la force de la classe annuelle de 1985. La biomasse total estimé a été 149.000 tonnes