Com influencia la temperatura en el creixement de les hortalisses en un hivernacle

Es presenten unes activitats experimentals sobre la influència de la temperatura en el creixement de les plantes i la germinació de les llavors dins i fora d'un hivernacle i com ho mesurem amb la consola de sensors Ecodad, realitzades per alumnes de quart de Primària. Les activitats es desenvolupen en un context que afavoreix l'ús de les Tecnologies de l'Aprenentatge i el Coneixement (TAC), incorporades a l'activitat de classe

Host species determines symbiotic community composition in Antarctic sponges (Porifera: Demospongiae)

The microbiota of four Antarctic sponges, Dendrilla antarctica, Sphaerotylus antarcticus, Mycale acerata, and Hemigellius pilosus, collected at two South Shetland Islands and at two locations in the Antarctic Peninsula separated by ca. 670 km, were analyzed together with surrounding seawater. We used high throughput sequencing of the V4 region of the 16S rRNA gene common to Bacteria and Archaea to investigate the prokaryotic diversity and community composition. Our study reveals that sponge-associated prokaryote communities are consistently detected within a particular sponge species regardless of the collection site. Their community structure and composition are typical of low microbial abundance (LMA) sponges. We conclude that prokaryote communities from Antarctic sponges are less diverse and differ in their composition compared to those in the water column. Microbiome analysis indicates that Antarctic sponges harbor a strict core consisting of seven OTUs, and a small variable community comprising several tens of OTUs. Two abundant prokaryotes from the variable microbiota that are affiliated to the archaeal and bacterial phyla Thaumarchaeota and Nitrospirae may be involved in the sponge nitrification process and might be relevant components of the nitrogen cycling in Antarctica. The likely generalist nature of dominant microbes and the host-specific structure of symbiont communities suggest that these Antarctic sponges represent different ecological niches for particular prokaryotic enrichments

J2 effect and the collision restricted three–body problem

The existence of a new class of inclined periodic orbits of the collision restricted three–body problem is shown. The symmetric periodic solutions found are perturbations of elliptic kepler orbits and they exist only for special values of the inclination and are related to the motion of a satellite around an oblate planet

Rubric co-construction for the assessment of STEM high school projects

En un contexto donde la enseñanza de las ciencias en educación secundaria frecuentemente se realiza a través de la metodología ABP, aparece la necesidad de disponer de instrumentos que permitan mejorar la calidad de los proyectos STEM que se implementan. Con esta finalidad, y a partir de un modelo de ciencia escolar basado en participar de las formas de hacer, pensar y hablar de las ciencias este estudio se plantea en el contexto de un proceso de co-construcción y validación por expertos de una rúbrica de mejora de proyectos STEM en 3 fases. En este escenario, se desarrolla una investigación evaluativa desde una aproximación cualitativa-interpretativa analizando el discurso de los expertos pertenecientes a un grupo de investigación en didáctica. De este análisis se identificaron 4 grandes tensiones en el consenso de indicadores para establecer criterios para la mejora de los proyectos.Regarding the growing use of PBL for teaching and learning high school Science, there appears the necessity of instruments that make STEM projects evaluation feasible. For that purpose, based on a cognitive model of Science Education that focuses on how scientist work, think and communicate, it was developed a coconstruction and validation process of a rubric instrument. Aided by an interdisciplinary research group on Science Education, the 3-step co-construction process was the context of an evaluative investigation from a qualitative-interpretative approach. By analyzing participants discourse, 4 major tensions were found to have direct implications on project improvement

Highly eccentric hip-hop solutions of the 2N-body problem

We show the existence of families of hip-hop solutions in the equal-mass 2N-body problem which are close to highly eccentric planar elliptic homographic motions of 2N bodies plus small perpendicular non-harmonic oscillations. By introducing a parameter Є, the homographic motion and the small amplitude oscillations can be uncoupled into a purely Keplerian homographic motion of fixed period and a vertical oscillation described by a Hill type equation. Small changes in the eccentricity induce large variations in the period of the perpendicular oscillation and give rise, via a Bolzano argument, to resonant periodic solutions of the uncoupled system in a rotating frame. For small Є ≠ 0, the topological transversality persists and Brouwer's fixed point theorem shows the existence of this kind of solutions in the full system.Postprint (author’s final draft

Hip-hop solutions of the 2N-body problem

Hip–Hop solutions of the 2N–body problem with equal masses are shown to exist using an analytic continuation argument. These solutions are close to planar regular 2N–gon relative equilibria with small vertical oscillations. For fixed N, an infinity of these solutions are three–imensional choreographies, with all the in the inertial frame.Peer ReviewedPostprint (author’s final draft

Indicadores contables para medir el riesgo. Utilidad de la información contable en el mercado español

El objetivo de este trabajo es analizar qué información contable permite medir el riesgo de las empresas que forman parte del Mercado de Capitales Español. Analizamos la información contable publicada por 73 empresas españolas, que cotizaban en el Mercado de Capitales Español durante el período 1992-2002, a través de siete indicadores. Estudiamos la conexión entre la información contable y la beta de las acciones, que es la medida de riesgo que proporciona el mercado de capitales. Analizamos la influencia que puede tener en el nivel de utilidad de la información contable, como medida del riesgo, el hecho de que la beta se determine utilizando el IBEX-35 o el IGBM (Índice General de la Bolsa de Madrid). Los resultados obtenidos muestran que solo utilizando el IBEX-35 existe cierta conexión entre la información contable y el riesgo de mercado, y que solo el endeudamiento y el ratio payout explican de forma significativa dicho riesgo

Antibiotic resistance genes in phage particles from Antarctic and Mediterranean seawater ecosystems

Anthropogenic activities are a key factor in the development of antibiotic resistance in bacteria, a growing problem worldwide. Nevertheless, antibiotics and resistances were being generated by bacterial communities long before their discovery by humankind, and might occur in areas without human influence. Bacteriophages are known to play a relevant role in the dissemination of antibiotic resistance genes (ARGs) in aquatic environments. In this study, five ARGs (blaTEM, blaCTX-M-1, blaCTX-M-9, sul1 and tetW) were monitored in phage particles isolated from seawater of two different locations: (i) the Mediterranean coast, subjected to high anthropogenic pressure, and (ii) the Antarctic coast, where the anthropogenic impact is low. Although found in lower quantities, ARG-containing phage particles were more prevalent among the Antarctic than the Mediterranean seawater samples and Antarctic bacterial communities were confirmed as their source. In the Mediterranean area, ARG-containing phages from anthropogenic fecal pollution might allow ARG transmission through the food chain. ARGs were detected in phage particles isolated from fish (Mediterranean, Atlantic, farmed, and frozen), the most abundant being -lactamases. Some of these particles were infectious in cultures of the fecal bacteria Escherichia coli. By serving as ARG reservoirs in marine environments, including those with low human activity, such as the Antarctic, phages could contribute to ARG transmission between bacterial communities

Psicosis y diferencias sociales: Comparando la prevalencia de las psicosis en dos medios urbanos diferenciados.

Objetivos: Contribuir a la reflexión sobre la etiología y/o los factores de riesgo para las psicosis comparando la prevalencia en población general y población de riesgo de la esquizofrenia y otras psicosis en dos barrios de Barcelona (España). Método: Nuestras aportaciones en este trabajo se apoyan sobre todo en un estudio descriptivo transversal de todos los pacientes con psicopatología detectados en la USM de Sant Martí-La Mina: un territorio geodemográfica y asistencialmente delimitado formado por 5 Áreas Básicas de Salud (103.615 habitantes. Resultados: Sobre un total de 21.536 pacientes con registro de casos abierto desde el año 1982 hasta el año 2000, se halló que 838 cumplían los criterios restrictivos para ser diagnosticados como “esquizofrénicos” (N=476) o “afectados por otras psicosis” (N=362). Sin embargo, las prevalencias de esquizofrenia y otras psicosis en el barrio sujeto a más factores de riesgo psicosociales eran alrededor de 2 veces mayores que las encontradas en el barrio colindante por el mismo equipo y en el mismo período temporal. Conclusión: Es necesario tener en cuenta el gran peso de los factores de sociales y psicosociales para poderse explicar las diferencias de prevalencia de la esquizofrenia y otras psicosis entre diferentes poblaciones