Differential activity of Drosophila Hox genes induces myosin expression and can maintain compartment boundaries

Compartments are units of cell lineage that subdivide territories with different developmental potential. In Drosophila, the wing and haltere discs are subdivided into anterior and posterior (A/P) compartments, which require the activity of Hedgehog, and into dorsal and ventral (D/V) compartments, needing Notch signaling. There is enrichment in actomyosin proteins at the compartment boundaries, suggesting a role for these proteins in their maintenance. Compartments also develop in the mouse hindbrain rhombomeres, which are characterized by the expression of different Hox genes, a group of genes specifying different structures along their main axis of bilaterians. We show here that the Drosophila Hox gene Ultrabithorax can maintain the A/P and D/V compartment boundaries when Hedgehog or Notch signaling is compromised, and that the interaction of cells with and without Ultrabithorax expression induces high levels of non-muscle myosin II. In the absence of Ultrabithorax there is occasional mixing of cells from different segments. We also show a similar role in cell segregation for the Abdominal-B Hox gene. Our results suggest that the juxtaposition of cells with different Hox gene expression leads to their sorting out, probably through the accumulation of non-muscle myosin II at the boundary of the different cell territories. The increase in myosin expression seems to be a general mechanism used by Hox genes or signaling pathways to maintain the segregation of different groups of cells.Peer Reviewe

CO^(12) mapping of the low-metallicity blue compact dwarf galaxy Markarian 86

We have mapped the CO^12 J = 1-0 and J = 2-1 line emission in Markarian 86, one of the most metal-deficient blue compact dwarf galaxies so far detected in CO^12. The CO^12 emission is distributed in a horseshoe-like structure that follows the locus of the most recent star formation regions. The minimum in molecular line emission corresponds to the position of an older, massive nuclear starburst. The H_2 mass of the galaxy [in the range of (0.4-5) x 10^7 M_⨀] and its morphology have been compared with the predictions of hydrodynamic simulations of the evolution of the interstellar medium surrounding a nuclear starburst. These simulations suggest that the physical conditions in the gas swept out by the starburst could have led to the formation of the ring of molecular gas reported here. This result provides an attractive scenario for explaining the propagation (in a galactic scale) of the star formation in dwarf galaxies

IMF - metallicity: a tight local relation revealed by the CALIFA survey

Variations in the stellar initial mass function (IMF) have been invoked to explain the spectroscopic and dynamical properties of early-type galaxies. However, no observations have yet been able to disentangle the physical driver. We analyse here a sample of 24 early-type galaxies drawn from the CALIFA survey, deriving in a homogeneous way their stellar population and kinematic properties. We find that the local IMF is tightly related to the local metallicity, becoming more bottom-heavy towards metal-rich populations. Our result, combined with the galaxy mass-metallicity relation, naturally explains previous claims of a galaxy mass-IMF relation, derived from non-IFU spectra. If we assume that - within the star formation environment of early-type galaxies - metallicity is the main driver of IMF variations, a significant revision of the interpretation of galaxy evolution observables is necessary.Comment: Accepted for publication in ApJL. 6 pages, 4 figure

Students’ Factors Affecting Undergraduates’ Perceptions of their Teaching and Learning Process within ECTS Experience

Introduction: In the present study, we investigated the potential factors that influenced the level of students satisfaction with the teaching–learning process (TLP), from the perspective of students participating in the European Credit Transfer System (ECTS) experience. Method: A total of 1490 students from the Universities of Almería and Granada (Spain) participated in an evaluation of their class discipline area. They completed the new revised protocol for evaluating the ECTS experience. Analyses of variance were carried out, taking the following factors as independent variables: student's grade average, year in school, study discipline, credit load in terms of ECTS credits assigned to a subject, the e-learning approach. Perception of the TLP was used as the dependent variable. Results: The data analyses showed variability of the degree of statistically significance among the factors that influenced students’ perceptions of the TLP. These factors included: Student's grade average (in favor of high performers), year in school (in favor of earlier years), ECTS load (in favor of subjects with a medium load of credits), and e-learning (in favor of its use). These research findings provided evidence to explore the delineation of a potential profile of factors that trigger a favorable perception of the TLP. Discussion and Conclusion: The present findings certainly have implications to deepen our understanding of the core beliefs, commitment, and the experience in shaping the implementation of the European Higher Education Area through the ECTS

Transcriptomic profile induced in bone marrow mesenchymal stromal cells after interaction with multiple myeloma cells: implications in myeloma progression and myeloma bone disease

This is an open-access article distributed under the terms of the Creative Commons Attribution License.Despite evidence about the implication of the bone marrow (BM) stromal microenvironment in multiple myeloma (MM) cell growth and survival, little is known about the effects of myelomatous cells on BM stromal cells. Mesenchymal stromal cells (MSCs) from healthy donors (dMSCs) or myeloma patients (pMSCs) were co-cultured with the myeloma cell line MM.1S, and the transcriptomic profile of MSCs induced by this interaction was analyzed. Deregulated genes after co-culture common to both d/pMSCs revealed functional involvement in tumor microenvironment cross-talk, myeloma growth induction and drug resistance, angiogenesis and signals for osteoclast activation and osteoblast inhibition. Additional genes induced by co-culture were exclusively deregulated in pMSCs and predominantly associated to RNA processing, the ubiquitine-proteasome pathway, cell cycle regulation, cellular stress and non-canonical Wnt signaling. The upregulated expression of five genes after co-culture (CXCL1, CXCL5 and CXCL6 in d/pMSCs, and Neuregulin 3 and Norrie disease protein exclusively in pMSCs) was confirmed, and functional in vitro assays revealed putative roles in MM pathophysiology. The transcriptomic profile of pMSCs co-cultured with myeloma cells may better reflect that of MSCs in the BM of myeloma patients, and provides new molecular insights to the contribution of these cells to MM pathophysiology and to myeloma bone disease.This work was supported by grants from the Spanish MINECO-ISCIII (PI12/02591, PI12/00624) and FEDER (European Funds for Regional Development); the Centro en Red for Regenerative Medicine and Cellular Therapy from Castilla y León; the Spanish Health Thematic Network of Cooperative Research in Cancer (RTICC RD12/0056/0058 and RD12/0036/0003), and Spanish FIS (PS09/01897 and PS09/00843). AG-G received support from the Centro en Red for Regenerative Medicine and Cellular Therapy from Castilla y León and from the Spanish Society of Hematology and Hemotherapy (SEHH), and EDR from the Spanish Association for Cancer Research (AECC).Peer Reviewe

MEGARA focal plane subsystems

MEGARA (Multi-Espectrografo en GTC de Alta Resolucion para Astronomia) is the future optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for GTC. The Fiber Units are placed at one Folded Cassegrain focus and feed the spectrograph located on a Nasmyth-type platform. This paper summarizes the status of the design of the MEGARA Folded Cassegrain Subsystems after the PDR (held on March 2012), as well as the prototyping that has been carried out during this phase. The MEGARA Fiber Unit has two IFUs: a Large Compact Bundle covering 12.5 arcsec x 11.3 arcsec on sky (100 microns fiber-core), and a Small Compact Bundle, of 8.5 arcsec x 6.7 arcsec (70 microns fiber-core), plus a Fiber MOS positioner, able to place up to 100 mini-bundles 7 fibers each (100 microns fiber-core) in MOS configuration within a 3.5arcmin x 3.5arcmin FOV. A field lens provides a telecentric focal plane where the fibers are located. Microlens arrays couple the telescope beam to the collimator focal ratio at the entrance of the fibers (providing the f/17 to f/3 focal ratio reduction to enter into the fibers). Finally, the fibers, organized in bundles, end in the pseudo-slit plate, which will be placed at the entrance focal plane of the MEGARA spectrographs

Una metodología para la realización y evaluación efectiva de exámenes de programación usando el ordenador

El uso de ordenadores durante los exámenes de programación es una demanda muy habitual entre los estudiantes universitarios. En este trabajo se presenta una metodología para evaluar a los estudiantes de un curso de programación, que incorpora como novedad principal el uso del ordenador, por parte de los estudiantes, durante el examen. El trabajo comienza justificando las ventajas del uso del ordenador durante el examen y explicando los retos que introduce. Luego, se describen los diferentes procedimientos que componen la metodología propuesta: prácticas en casa, test unitarios, exámenes prácticos y exámenes tipo test. También se describen en este trabajo dos herramientas que se han desarrollado ad-hoc para complementar dicha metodología. La primera herramienta tiene por objetivo impedir el uso fraudulento del ordenador durante el examen. La segunda herramienta sirve para semiautomatizar la corrección de los exámenes. Finalmente, en este trabajo se analizan los resultados obtenidos antes y después de la aplicación de la metodología propuesta. De este análisis se deriva que el uso del ordenador durante el examen parece ofrecer una calificación más objetiva de los estudiantes.The use of computers during programming exams is a very habitual demand of the computer grade students. In this paper, a methodology for programming courses is presented, whose main innovation consists of using computers during the exams. This work begins justifying the advantages of using the computer during the exams and explaining the challenges that it introduces. Later, the procedures of the proposed methodology are described: unit tests, multiple choice questions, practical exams and home work exercises. We also describe two tools that had been developed to support these procedures. The first one avoids a fraudulent use of the computer during the exam. The second one is used to automatize the correction of the exams. In this work, we analyze the results obtained before and after the application of the proposed methodology. From this analysis, we notice that the use of computers during the exams allow us to get a more objective qualification of the student.Proyecto TIN2014-57458-R