Light-sheet microscopy: a tutorial

This paper is intended to give a comprehensive review of light-sheet (LS) microscopy from an optics perspective. As such, emphasis is placed on the advantages that LS microscope configurations present, given the degree of freedom gained by uncoupling the excitation and detection arms. The new imaging properties are first highlighted in terms of optical parameters and how these have enabled several biomedical applications. Then, the basics are presented for understanding how a LS microscope works. This is followed by a presentation of a tutorial for LS microscope designs, each working at different resolutions and for different applications. Then, based on a numerical Fourier analysis and given the multiple possibilities for generating the LS in the microscope (using Gaussian, Bessel, and Airy beams in the linear and nonlinear regimes), a systematic comparison of their optical performance is presented. Finally, based on advances in optics and photonics, the novel optical implementations possible in a LS microscope are highlighted.Peer ReviewedPostprint (published version

Factors Considered in the Assessment of Computer Science Engineering Capstone Projects and their Influence on Discrepancies between Assessors

A capstone project is an extensive learning experience traditionally developed during a student’s final academic year. Assessing such a complex assignment involves several challenges and is usually based upon the evaluations of at least two different people: the capstone project advisor, and one or more other assessors. Quantitative studies comparing only different assessors' grades and qualitative studies investigating the origin of possible discrepancies have been conducted. In both cases, contradictory conclusions were reached. The objective of this study is to analyze the factors that are given consideration by assessors of engineering capstone projects and the influence of these factors on the discrepancies between different assessors’ opinions of the same project. This study quantitatively examined 162 computer science engineering capstone projects developed by one student and supervised by one advisor. Each project was assessed by the project advisor and a committee. For each project, the advisor and the committee were asked to complete an additional questionnaire on product characteristics, student competences, and project supervision. Competences demonstrated by the student were found to be the most relevant element when a capstone project was evaluated by the advisor and the committee; product characteristics were found to be second in influence. Furthermore, advisors grant minor significance to the advisor-involvement component. Discrepancies between grades seem to be associated with those aspects to which one assessor has access, while the other does not, such as student skills demonstrated during project development or their performance in the oral defense. Both the advisor’s and the committee’s perspectives are important in the assessment of this complex task and they complement one another

Evolution and interspecies transmission of canine distemper virus—an outlook of the diverse evolutionary landscapes of a multi-host virus

This article belongs to the Special Issue MorbillivirusesCanine distemper virus (CDV) is a worldwide distributed virus which belongs to the genus Morbillivirus within the Paramyxoviridae family. CDV spreads through the lymphatic, epithelial, and nervous systems of domestic dogs and wildlife, in at least six orders and over 20 families of mammals. Due to the high morbidity and mortality rates and broad host range, understanding the epidemiology of CDV is not only important for its control in domestic animals, but also for the development of reliable wildlife conservation strategies. The present review aims to give an outlook of the multiple evolutionary landscapes and factors involved in the transmission of CDV by including epidemiological data from multiple species in urban, wild and peri-urban settings, not only in domestic animal populations but at the wildlife interface. It is clear that different epidemiological scenarios can lead to the presence of CDV in wildlife even in the absence of infection in domestic populations, highlighting the role of CDV in different domestic or wild species without clinical signs of disease mainly acting as reservoirs (peridomestic and mesocarnivores) that are often found in peridomestic habits triggering CDV epidemics. Another scenario is driven by mutations, which generate genetic variation on which random drift and natural selection can act, shaping the genetic structure of CDV populations leading to some fitness compensations between hosts and driving the evolution of specialist and generalist traits in CDV populations. In this scenario, the highly variable protein hemagglutinin (H) determines the cellular and host tropism by binding to signaling lymphocytic activation molecule (SLAM) and nectin-4 receptors of the host; however, the multiple evolutionary events that may have facilitated CDV adaptation to different hosts must be evaluated by complete genome sequencing. This review is focused on the study of CDV interspecies transmission by examining molecular and epidemiological reports based on sequences of the hemagglutinin gene and the growing body of studies of the complete genome; emphasizing the importance of long-term multidisciplinary research that tracks CDV in the presence or absence of clinical signs in wild species, and helping to implement strategies to mitigate the infection. Integrated research incorporating the experience of wildlife managers, behavioral and conservation biologists, veterinarians, virologists, and immunologists (among other scientific areas) and the inclusion of several wild and domestic species is essential for understanding the intricate epidemiological dynamics of CDV in its multiple host infections

Do protected areas conserve neotropical freshwater fishes? A case study of a biogeographic province in Venezuela

¿Las áreas protegidas conservan los peces continentales neotropicales? un caso de estudio para una provincia biogeográfica en Venezuela La efectividad de las áreas protegidas para la conservación de peces continentales es limitada ya que generalmente estas no son congruentes con los patrones regionales de la riqueza y distribución de las especies de peces. Como caso de estudio comparamos la riqueza, distribución y abundancia de la ictiofauna en ríos costeros de una provincia biogeográfica de Venezuela para determinar su estatus de conservación. Además, también estimamos la efectividad de las áreas protegidas para la conservación de la ictiofauna según la riqueza y distribución de especies en diferentes unidades fisiográficas y afluentes. La ictiofauna (72 spp., ~30% endémicas; ~10% amenazadas) se distribuyó acorde con la orografía, cuencas y unidades fisiográficas. La mayoría de áreas protegidas evidenciaron una efectividad baja para la conservación de peces, principalmente porque eran muy pequeñas o incluían sólo fragmentos de afluentes o cuencas, o porque estaban localizadas en zonas de montaña, donde la diversidad de especies era mínima. Para proteger con eficacia adecuada a a los peces continentales de la provincia, las áreas protegidas existentes deberían ser modificadas y expandidas. Palabras clave: Biodiversidad acuática, Provincia biogeográfica, Parques nacionales, Ríos costeros.The effectiveness of protected areas to conserve freshwater fishes is limited because these areas are not usually congruent with regional patterns of fish species richness and distribution. We compared the richness, distribution and abundance of coastal freshwater fishes in a biogeographic province of Venezuela to determine their conservation status. We also estimated the relevance of existing protected areas in conserving fishes in different physiographic units and tributaries by evaluating species richness and distribution. The ichthyofauna (72 spp., ~30% endemic, ~10% threatened) was distributed according to orography, drainage and physiographic units. Most protected areas had limited effectiveness for fish conservation, mainly because they were too small or included only fragments of tributaries or drainages, or because they were located only in highland drainages where species diversity was minimal. To adequately protect freshwater fishes in this province the existing protected areas should be modified and expanded. Key words: Aquatic biodiversity, Biogeographic province, National parks, Coastal rivers.¿Las áreas protegidas conservan los peces continentales neotropicales? un caso de estudio para una provincia biogeográfica en Venezuela La efectividad de las áreas protegidas para la conservación de peces continentales es limitada ya que generalmente estas no son congruentes con los patrones regionales de la riqueza y distribución de las especies de peces. Como caso de estudio comparamos la riqueza, distribución y abundancia de la ictiofauna en ríos costeros de una provincia biogeográfica de Venezuela para determinar su estatus de conservación. Además, también estimamos la efectividad de las áreas protegidas para la conservación de la ictiofauna según la riqueza y distribución de especies en diferentes unidades fisiográficas y afluentes. La ictiofauna (72 spp., ~30% endémicas; ~10% amenazadas) se distribuyó acorde con la orografía, cuencas y unidades fisiográficas. La mayoría de áreas protegidas evidenciaron una efectividad baja para la conservación de peces, principalmente porque eran muy pequeñas o incluían sólo fragmentos de afluentes o cuencas, o porque estaban localizadas en zonas de montaña, donde la diversidad de especies era mínima. Para proteger con eficacia adecuada a a los peces continentales de la provincia, las áreas protegidas existentes deberían ser modificadas y expandidas. Palabras clave: Biodiversidad acuática, Provincia biogeográfica, Parques nacionales, Ríos costeros

Ensambles algales en un microecosistema natural de la planta carnívora tropical utricularia foliosa l.

Se estudió la abundancia y la composición de los ensambles algales asociadosa Utricularia foliosa en siete plantas localizadas en la quebrada Yahuarcaca(Amazonas - Colombia). Los objetivos fueron determinar los ensambles algalesdentro del microecosistema de U. foliosa y sus variaciones de acuerdo con lascondiciones de los nutrientes. Los cambios en la riqueza y la abundancia de losensambles estuvieron infl uenciados por las fl uctuaciones en el nivel del agua y laconcentración de PO . En los ensambles de aguas abiertas se observó la dominanciade cianobacterias heterocitadas, diatomeas y organismos de gran capacidad móvilcomo euglenófi tos. Las condiciones del microambiente creadas por U. foliosacontrolan la diversidad y las densidades algales. Esto hace muy posible que U.foliosa genere condiciones fi siológicas óptimas que favorecen una alta riquezade especies tico-epífi tas como desmidias y diatomeas perifíticas. Se forma así unmicroecosistema del cual obtiene más benefi cios de la comunidad que de la mismaestrategia de la carnivoría desarrollada por U. foliosa. Se analiza además la relaciónentre la composición algal y las variables físicas y químicas por medio de un análisisde correspondencia canónica distendida

Epr and magnetic properties on lacamno manganites

Electron paramagnetic resonance (EPR) and AC Susceptibility measurements were carried out as a function of temperature on La0,7Ca0,3MnO3 polycrystalline samples. The samples displayed a transition from paramagnetic-insulator to ferromagnetic-metal at Tc around 261K. Tc was determined from the inverse of the real part of a.c. susceptibility (1/X’) vs temperature, which follows a simple Curie-Weiss behavior. The inverse of the EPR intensity also follows a Curie-Weiss type behavior down toTEPR = 253 K.. The structure of the samples as determined by X-Ray diffraction (XRD) corresponds to a single perovskite phase with orthorhombic unit cell.Electron paramagnetic resonance (EPR) and AC Susceptibility measurements were carried out as a function of temperature on La0,7Ca0,3MnO3 polycrystalline samples. The samples displayed a transition from paramagnetic-insulator to ferromagnetic-metal at Tc around 261K. Tc was determined from the inverse of the real part of a.c. susceptibility (1/X’) vs temperature, which follows a simple Curie-Weiss behavior. The inverse of the EPR intensity also follows a Curie-Weiss type behavior down toTEPR = 253 K.. The structure of the samples as determined by X-Ray diffraction (XRD) corresponds to a single perovskite phase with orthorhombic unit cell

Valoración de los estilos de dirección de proyectos fin de carrera en ingeniería informática

Completamos aquí un estudio realizado sobre dirección de proyectos fin de carrera (PFC) en Ingeniería Informática. Entonces usamos una encuesta para determinar una tipología de estilos de dirección de PFC. Resumimos ahora los resultados de aquel estudio, ampliándolo con nuevos ratios para valorar los resultados de la aplicación de cada estilo en cuanto a calificación, duración del PFC y tiempo dedicado por el director, teniendo en cuenta el tipo de alumno. Estos resultados pueden ayudar a los tutores de PFC a encontrar distintas formas de dirección a utilizar.SUMMARY -- This paper complements a previous study we conducted on capstone projects in Computer Science Engineering. Then we used a survey to determine a typology of supervision styles for that projects. This article summarizes the results of that study, extending them with new ratios to assess the results of the application of each style in terms of grade obtained, duration and time spent by the director, considering the type of student. These results can help supervisors to find other ways of supervision