7,243 research outputs found

    Integración de la educación ambiental en el currículo a nivel de aula. El caso de la experiencia ecocentros

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    Trece centros educativos de infantil y primaria de la región extremeña participaron en un proyecto de investigación educativa (Ecocentros) basado en las experiencias conocidas como ecoauditorías escolares. En esta investigación se pretende conocer cómo se desarrolló la integración de la educación ambiental en el aula teniendo en cuenta para ello las acciones que se llevaron a cabo, y que figuraban en la memoria interna elaborada por el profesorado de los centros participantes a lo largo de dos cursos consecutivos. El qué se incorpora al currículo y cómo se hace, es esencial para comprender en qué medida esta experiencia contribuye a llevar a cabo los objetivos de la educación ambiental para el desarrollo sostenible

    Caracteres preimaginales y aspectos bionómicos de Gyriosomus luczotii Laporte, 1840 (Coleoptera, Tenebrionidae)

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    Se describe la morfología y microestructura coriónica del huevo y la morfología del primer estadio larvario de Gyriosomus luczotii Laporte, 1840 (Coleoptera, Tenebrionidae, Nycteliini). También se exponen antecedentes bionómicos y distribucionales de la especie. Para la obtención de huevos y larvas, se recolectaron parejas en el terreno que fueron mantenidas en cajas de cria hasta la ovoposición y posterior eclosión. La estructura y ornamentación del exocorion del huevo y características morfológicas externas de la larva fueron analizadas mediante microscopía electrónica de barrido. Los resultados muestran que los huevos de G. luczotii presentan un micropilo redondeado y exocorion liso, con células hexagonales sin aeropilos. Las larvas de G. luczotii presentan características morfológicas adaptativas para la vida edáfica del tipo Pedobionta: cápsula cefálica con gran cantidad de sensillas, patas protorácicas de función cavadora, y pigopodio bien desarrollado. Se analiza la importancia de algunos caracteres morfológicos de la larva de primer estadio como criterio de diagnóstico específico y se establece que las diferencias interespecíficas referidas a las sensillas frontales, la forma del clípeo y el margen anterior del labro tienen valor taxonómico y probablemente filogenético. Palabras clave: Tenebrionidae, Gyriosomus, Morfología, Estadios preimaginales, Desierto costero, Chile.Preimaginal characters and bionomical aspects of Gyriosomus luczotii Laporte, 1840 (Coleoptera, Tenebrionidae) We describe the morphology and microstructure of the egg chorion, and the morphology of the first instar larva of Gyriosomus luczotii Laporte, 1840 (Coleoptera, Tenebrionidae, Nycteliini). Bionomical and distributional data on this species are also provided. To obtain eggs and larvae, couples were collected in the field and kept in rearing cages until oviposture and ecclosion. The structure and adornment of the egg exochorion, and the exterior morphological features of larvae were examined with electron scanning microscopy. The eggs of G. luczotii showed a rounded micropyle and a smooth exochorion, composed of hexagonal cells without aeropyles. The larvae of G. luczotii showed morphological characteristics suited for an edaphic life similar to that of Pedobionta: digging prothoracic legs, cephalic capsule with abundant sensilla, and well–developed pygopodium. We analysed the importance of larval morphology as an element for specific diagnosis and found that interspecific differences regarding frontal sensilla, clypeus shape, and anterior part of labrum, had a taxonomic value and possibly a phylogenetic value. Key words: Tenebrionidae, Gyriosomus, Morphology, Preimaginal stages, Coastal desert, Chile.Se describe la morfología y microestructura coriónica del huevo y la morfología del primer estadio larvario de Gyriosomus luczotii Laporte, 1840 (Coleoptera, Tenebrionidae, Nycteliini). También se exponen antecedentes bionómicos y distribucionales de la especie. Para la obtención de huevos y larvas, se recolectaron parejas en el terreno que fueron mantenidas en cajas de cria hasta la ovoposición y posterior eclosión. La estructura y ornamentación del exocorion del huevo y características morfológicas externas de la larva fueron analizadas mediante microscopía electrónica de barrido. Los resultados muestran que los huevos de G. luczotii presentan un micropilo redondeado y exocorion liso, con células hexagonales sin aeropilos. Las larvas de G. luczotii presentan características morfológicas adaptativas para la vida edáfica del tipo Pedobionta: cápsula cefálica con gran cantidad de sensillas, patas protorácicas de función cavadora, y pigopodio bien desarrollado. Se analiza la importancia de algunos caracteres morfológicos de la larva de primer estadio como criterio de diagnóstico específico y se establece que las diferencias interespecíficas referidas a las sensillas frontales, la forma del clípeo y el margen anterior del labro tienen valor taxonómico y probablemente filogenético. Palabras clave: Tenebrionidae, Gyriosomus, Morfología, Estadios preimaginales, Desierto costero, Chile

    Functional characterization of tissue inhibitor of metalloproteinase-1 (TIMP-1) N- and C-terminal domains during xenopus laevis development

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    Extracellular matrix (ECM) remodeling is essential for facilitating developmental processes. ECM remodeling, accomplished by matrix metalloproteinases (MMPs), is regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs). While the TIMP N-terminal domain is involved in inhibition of MMP activity, the C-terminal domain exhibits cell-signaling activity, which is TIMP and cell type dependent. We have previously examined the distinct roles of the Xenopus laevis TIMP-2 and -3 C-terminal domains during development and here examined the unique roles of TIMP-1 N- and C-terminal domains in early X. laevis embryos. mRNA microinjection was used to overexpress full-length TIMP-1 or its individual N- or C-terminal domains in embryos. Full-length and C-terminal TIMP-1 resulted in increased lethality compared to N-terminal TIMP-1. Overexpression of C-terminal TIMP-1 resulted in significant decreases in mRNA levels of proteolytic genes including TIMP-2, RECK, MMP-2, and MMP-9, corresponding to decreases in MMP-2 and -9 protein levels, as well as decreased MMP-2 and MMP-9 activities. These trends were not observed with the N-terminus. Our research suggests that the individual domains of TIMP-1 are capable of playing distinct roles in regulating the ECM proteolytic network during development and that the unique functions of these domains are moderated in the endogenous full-length TIMP-1 molecule. © 2014 M. A. Nieuwesteeg et al

    Cabin-fuselage-wing structural design concept with engine installation

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    The purpose of this project is to provide a fuselage structural assembly and wing structural design that will be able to withstand the given operational parameters and loads provided by Federal Aviation Regulation Part 23 (FAR 23) and the Statement of Work (SOW). The goal is to provide a durable lightweight structure that will transfer the applied loads through the most efficient load path. Areas of producibility and maintainability of the structure will also be addressed. All of the structural members will also meet or exceed the desired loading criteria, along with providing adequate stiffness, reliability, and fatigue life as stated in the SOW. Considerations need to be made for control system routing and cabin heating/ventilation. The goal of the wing structure and carry through structure is also to provide a simple, lightweight structure that will transfer the aerodynamic forces produced by the wing, tailboom, and landing gear. These forces will be channeled through various internal structures sized for the pre-determined loading criteria. Other considerations were to include space for flaps, ailerons, fuel tanks, and electrical and control system routing. The difficulties encountered in the fuselage design include expanding the fuselage cabin to accept a third occupant in a staggered configuration and providing ample volume for their safety. By adding a third person the CG of aircraft will move forward so the engine needs to be moved aft to compensate for the difference in the moment. This required the provisions of a ring frame structure for the new position of the engine mount. The difficulties encountered in the wing structural design include resizing the wing for the increased capacity and weight, and compensating for a large torsion produced by the tail boom by placing a great number of stiffeners inside the boom, which will result in the relocation of the fuel tank. Finally, an adequate carry through structure for the wing and fuselage interface will be designed to effectively transmit loads through the fuselage

    Effect of jumbo squid (Dosidicus gigas) skin extract on the microbial activity in chilled mackerel (Scomber scombrus)

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    6 páginas, 4 tablas, 2 figurasDuring the industrial processing of jumbo squid (Dosidicus gigas), large amounts of by-products containing biological active compounds are generated. In this study, aqueous solutions including acetic acid-ethanol extracts of jumbo squid skin (JSS) were tested at three different concentrations as icing media. The effects of the JSS extracts on the quality evolution of chilled mackerel (Scomber scombrus) were monitored. A significant inhibition (p < 0.05) of microbial activity was determined in the fish batch corresponding to the icing condition including the highest JSS concentration. Additionally, fish specimens corresponding to batches including any of the JSS concentrations tested showed lower (p < 0.05) proteolytic counts and pH values than control mackerel. Sensory analysis revealed a marked shelf life extension in chilled mackerel stored in ice including the highest JSS concentration; specimens from such batch were found to be still acceptable after 13 days of storage, while all other mackerel batches were rejectable. The marked microbial activity inhibition observed could be explained on the basis of the presence in ice of lipophilic compounds obtained by acetic acid-ethanol extraction of JSSThis work was supported by the CONACYT-Mexico grant 154046 and the Consejo Superior de Investigaciones Científicas (CSIC) through Research Project PIE 201370E001Peer reviewe

    A new method for the estimation of variance matrix with prescribed zeros in nonlinear mixed effects models

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    We propose a new method for the Maximum Likelihood Estimator (MLE) of nonlinear mixed effects models when the variance matrix of Gaussian random effects has a prescribed pattern of zeros (PPZ). The method consists in coupling the recently developed Iterative Conditional Fitting (ICF) algorithm with the Expectation Maximization (EM) algorithm. It provides positive definite estimates for any sample size, and does not rely on any structural assumption on the PPZ. It can be easily adapted to many versions of EM.Comment: Accepted for publication in Statistics and Computin

    Spontaneous intratumoral bleeding and rupture of giant gastric stromal tumor (> 30 cm) in a young patient

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    <p>Abstract</p> <p>Background</p> <p>Few cases of GIST bigger than 15 cm have been reported in medical literature, all primarily in elderly patients. We report an unusual case, in which a giant gastric GIST – in a young patient – presented as spontaneous intratumoral bleeding followed by intraluminal rupture.</p> <p>Case presentation</p> <p>A 37-year-old man was admitted with an acute onset of abdominal pain. CT showed a 32 × 25 cm mass with some cystic lesions and areas of calcification. Twelve hours after admission the patient presented with an episode of upper GI bleeding, and a significant decrease of tumor size and hemoglobin level. An upper endoscopy showed a large bulge in the posterior aspect of the gastric wall, and a small ulcer with continuous bleeding coming from a central orifice. A subtotal gastrectomy was carried out. Pathological examination showed a giant gastric GIST measuring 32 × 25 × 21 cm and weighing 3.750 g. Immunohistochemical staining demonstrated positive reactivity to C-kit protein, CD34, and α-smooth muscle actin; but negative reactivity to S-100 protein.</p> <p>Conclusion</p> <p>Intratumoral bleeding is a very rare presentation of GIST; preoperative diagnosis is always made difficult by the absence of pathognomonic signs or symptoms. Emergency local excision with negative margins associated with adjuvant therapy with imatinib mesylate remains the main modality of treatment for high risk GISTs.</p

    Going Beyond Promoting: Preparing Students to Creatively Solve Future Problems

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    While we cannot know what problems the future will bring, we can be almost certain that solving them will require creativity. In this article we describe how our course, a first-year undergraduate mathematics course, supports creative problem solving. Creative problem solving cannot be learned through a single experience, so we provide our students with a blend of experiences. We discuss how the course structure enables creative problem solving through class instruction, during class activities, during out of class assessments, and during in class assessments. We believe this course structure increases student comfort with solving open-ended and ill-defined problems similar to what they will encounter in the real world

    Levels of insulin and HOMA-IR in adolescents in Saltillo, Coahuila, Mexico

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    An alarming rise of obesity in adolescents has been observed, placing them at risk of developing resistance to insulin (IR) and its adverse metabolic consequences such as diabetes mellitus type 2 (DM2), metabolic syndrome and cardiovascular disease. Objective: To know the prevalence of obesity, and the levels of glucose, insulin and HOMA-IR and its association with the BMIz, waist circumference and the pubertal stage in a random sample of adolescents. Materials and methods: 292 adolescents between 12 and 15 years (152 female and 140 male), whose anthropometric measurements (weight, height and waist circumference) were taken, body mass index calculated and Z-score determined. Blood glucose and insulin levels were evaluated from a sample of blood and their HOMA-IR was determined. Results: The results showed that 32.5% were obese, 22.3% were overweight and 23.6% showed adolescent central obesity. Glucose levels (p = 0.016), insulin (p = 0.0001) and HOMA-IR (p = 0.0001) showed significant differences in the group with obesity. Values of the three parameters were increased with the stage of puberty. We found significant differences in the levels of glucose (p = 0.0388), insulin (p = 0.0005) and HOMA-IR (p = 0.0001) between the prepubertal and postpubertal stages

    Transfer Functions for Protein Signal Transduction: Application to a Model of Striatal Neural Plasticity

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    We present a novel formulation for biochemical reaction networks in the context of signal transduction. The model consists of input-output transfer functions, which are derived from differential equations, using stable equilibria. We select a set of 'source' species, which receive input signals. Signals are transmitted to all other species in the system (the 'target' species) with a specific delay and transmission strength. The delay is computed as the maximal reaction time until a stable equilibrium for the target species is reached, in the context of all other reactions in the system. The transmission strength is the concentration change of the target species. The computed input-output transfer functions can be stored in a matrix, fitted with parameters, and recalled to build discrete dynamical models. By separating reaction time and concentration we can greatly simplify the model, circumventing typical problems of complex dynamical systems. The transfer function transformation can be applied to mass-action kinetic models of signal transduction. The paper shows that this approach yields significant insight, while remaining an executable dynamical model for signal transduction. In particular we can deconstruct the complex system into local transfer functions between individual species. As an example, we examine modularity and signal integration using a published model of striatal neural plasticity. The modules that emerge correspond to a known biological distinction between calcium-dependent and cAMP-dependent pathways. We also found that overall interconnectedness depends on the magnitude of input, with high connectivity at low input and less connectivity at moderate to high input. This general result, which directly follows from the properties of individual transfer functions, contradicts notions of ubiquitous complexity by showing input-dependent signal transmission inactivation.Comment: 13 pages, 5 tables, 15 figure
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