αE-catenin-dependent mechanotransduction is essential for proper convergent extension in zebrafish

Cadherin complexes mediate cell-cell adhesion and are crucial for embryonic development. Besides their structural function, cadherin complexes also transduce tension across the junction-actomyosin axis into proportional biochemical responses. Central to this mechanotransduction is the stretching of the cadherin-F-actin-linker α-catenin, which opens its central domain for binding to effectors such as vinculin. Mechanical unfolding of α -catenin leads to force-dependent reinforcement of cadherin-based junctions as studied in cell culture. The importance of cadherin mechanotransduction for embryonic development has not been studied yet. Here we used TALEN-mediated gene disruption to perturb endogenous αE-catenin in zebrafish development. Zygotic α-catenin mutants fail to maintain their epithelial barrier, resulting in tissue rupturing. We then specifically disrupted mechanotransduction, while maintaining cadherin adhesion, by expressing an αE-catenin construct in which the mechanosensitive domain was perturbed. Expression of either wild-type or mechano-defective α-catenin fully rescues barrier function in α-catenin mutants. Expression of mechano-defective α-catenin, however, also induces convergence and extension defects. Specifically, the polarization of cadherin-dependent, lamellipodia-driven cell migration of the lateral mesoderm was lost. These results indicate that cadherin mechanotransduction is crucial for proper zebrafish morphogenesis and uncover one of the essential processes affected by its perturbation

Integrated water vapor obtained by satellite-borne instruments: evaluation with GPS measurements in the Iberian Peninsula

Ponencia presentada en: XVIII Congreso de la Asociación Española de Teledetección celebrado en Valladolid del 24 al 27 septiembre 2019.[ES]Este trabajo se centra en comparar los productos de vapor de agua integrado (IWV) de varios satélites respecto a un conjunto de datos en tierra obtenidos de GPS en nueve estaciones de la Península Ibérica. Los instrumentos satelitales son: Global Ozone Monitoring Instrument (GOME-2), Moderate-Resolution Imaging Spectroradiometer (MODIS), Ozone Monitoring Instrument (OMI), Spining Enhanced Visible and InfraRed Imager (SEVIRI), Atmospheric Infrared Sounder (AIRS), y Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY). Los productos de estos satélites muestran una buena correlación con respecto al producto de GPS (R2 ~ 0.7). Todos los satélites muestran cierta tendencia a sobrestimar los valores bajos de vapor de agua y a subestimar los altos. Además, la precisión, medida mediante el rango intercuartílico (IQR) también disminuye rápidamente al aumentar el IWV. Por otro lado, otro factor importante es el ángulo solar zenital (SZA) que influye en el rendimiento de los instrumentos satelitales, especialmente aquellos que dependen de la radiación solar. Al aumentar el SZA acercándose a 90°, los instrumentos pierden rendimiento aumentando la sobrestimación y el IQR. Sin embargo, a valores de SZA mayores de 90° (esto es, la noche) los índices calculados no tienen grandes dependencias con el SZA.[EN]This work focuses in the comparison of several integrated water vapor (IWV) from several satellites with respect to a dataset from ground-based GPS IWV, in nine stations at the Iberian Peninsula. The satellite instruments are Global Ozone Monitoring Instrument (GOME-2), Moderate-Resolution Imaging Spectroradiometer (MODIS), Ozone Monitoring Instrument (OMI), Spinning Enhanced Visible and InfraRed Imager (SEVIRI), Atmospheric Infrared Sounder (AIRS), and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY). The products of this instruments show a fair correlation with respect to GPS product (R2 ~ 0.7). All satellites show a certain tendency to overestimation of low IWV values, while underestimating large IWV values. Moreover, the precision is studied using the inter-quartile range (IQR), which also decreases quickly when IWV increases. Another important factor is the solar zenith angle (SZA), which affects the performance of satellite instruments, especially those that are dependent on solar radiation. When SZA increases, going closer to 90°, the instruments had worse performance, increasing overestimation and IQR. Nevertheless, for SZA larger than 90° (that is to say, the night), the indexes do not show large dependencies on SZA

A stellar overdensity associated with the Small Magellanic Cloud

We report the discovery of a stellar over-density 8$^{\circ}$ north of the center of the Small Magellanic Cloud (Small Magellanic Cloud Northern Over-Density; SMCNOD) using data from the first two years of the Dark Energy Survey (DES) and the first year of the MAGellanic SatelLITEs Survey (MagLiteS). The SMCNOD is indistinguishable in age, metallicity and distance from the nearby SMC stars, being primarly composed of intermediate-age stars (6 Gyr, Z=0.001), with a small fraction of young stars (1 Gyr, Z=0.01). The SMCNOD has an elongated shape with an ellipticity of 0.6 and a size of $\sim$ 6x2 deg. It has an absolute magnitude of $M_V \cong$ -7.7, $r_h = 2.1$ kpc, and $\mu_V(r<r_h)$ = 31.2 mag arcsec$^{-2}$. We estimate a stellar mass of $\sim 10^5$ $M_{\odot}$, following a Kroupa mass function. The SMCNOD was probably removed from the SMC disk by tidal stripping, since it is located near the head of the Magellanic Stream, and the literature indicates likely recent LMC-SMC encounters. This scenario is supported by the lack of significant HI gas. Other potential scenarios for the SMCNOD origin are a transient over-density within the SMC tidal radius or a primordial SMC satellite in advanced stage of disruption.Comment: 14 pages, 10 color figure

Placing Transdisciplinarity in Context: A Review of Approaches to Connect Scholars, Society and Action

Complex sustainability problems (e.g., climate change) are challenging to understand and manage, leading to an increase in approaches that connect scholars to society and research to action (collaborative approaches). The transdisciplinary approach (TDA) represents one such approach. While TDA is new to many, there are several prior collaborative approaches including collaborative adaptive management, knowledge integration, participatory action research, and indigenous/local knowledge. Other contemporary and parallel approaches include citizen science, translational science, evidence-based practice, and knowledge with action. The varied disciplinary roots and problem areas contribute to a lack of interaction among these parallel but distinct approaches, and among the scholars and stakeholders who practice them. In this paper, we consider the connections, complementarities and contradictions among these distinct but related collaborative approaches. This review offers insights into the interaction between science and practice, including the importance of social processes and recognition of different ways of knowing, as well as how to conduct collaborative approaches on a variety of scales and think about how to generalize findings. The review suggests a need to rethink roles and relationships in the process of knowledge co-creation, both extending the roles of researchers and practitioners, creating new hybrid roles for &ldquo;pracademics&rdquo;, and placing greater awareness on issues of power