1,555 research outputs found
Cómo motivar a los estudiantes de secundaria mediante actividades de ciencias atractivas y divertidas
Se presenta una propuesta de formación del profesorado llevada a cabo durante dos cursos académicos (2006/08) con la finalidad de mejorar la motivación e interés de los estudiantes hacia el aprendizaje de las ciencias. Se diseñó e implementó un curso desde la perspectiva de una ciencia comprometida, pero también amena, creativa y divertida, incluyendo actividades interactivas realizadas en colaboración con el Museo de Ciencias Príncipe Felipe, experimentos de laboratorio, textos divulgativos con enfoques CTSA (Ciencia-Tecnología-Sociedad-Ambiente), juguetes científicos, así como el aporte de experiencias provenientes de otros países europeos (Alemania, Francia y Reino Unido). Esta iniciativa, en la que han participado 80 profesores ha sido un instrumento eficaz tanto para la mejora de la motivación como para promover la formación de comunidades de práctica
The Use of Amniotic Membrane in the Management of Complex Chronic Wounds
Chronic wounds do not follow the usual wound healing process; instead, they are stuck in the inflammatory or proliferative phase. This is particularly evident in large, massive wounds with considerable tissue loss, which become senescent and do not epithelialize. In these wounds, we need to remove all the factors that prevent or delay normal wound healing. After that, soft tissue granulation is stimulated by local negative pressure therapy. Lastly, after the granulation is completed, the epithelialization process must be activated. Although a plethora of wound dressings and devices are available, chronic wounds persist as a unresolved medical concern. We have been using frozen amniotic membrane (AM) to treat this type of wounds with good results. Our studies have shown that AM is able to induce epithelialization in large wounds that were unable to epithelialize. AM induces several signaling pathways involved in cell migration and/or proliferation. Among those, we can highlight the mitogen‐activated protein kinase (MAPK) and Jun N‐terminal kinase (JNK) signaling pathways. Additionally, AM is able to selectively antagonise the anti-proliferative effect of TGFß by modifying its genetic program on keratinocytes. The combined effect of AM on keratinocytes, promoting cell proliferation/migration and antagonising TGFß-effect, is the perfect combination allowing chronic wounds to progress into epithelialization
Porcine circovirus 3 is highly prevalent in serum and tissues and may persistently infect wild boar (Sus scrofa scrofa)
Porcine circovirus 3 (PCV‐3) prevalence has been minimally investigated in wild boar; dynamics of infection and viral tissue distribution are currently unknown. In this study, serum samples from 518 wild boar (from years 2004 to 2018) were used to study frequency of infection. Also, serum samples from 19 boar captured and recaptured at least two times for a period of time from 1 month to 1 year were collected to determine PCV‐3 infection dynamics. Finally, to elucidate PCV‐3 DNA organic distribution, sera, different tissues and faeces were obtained from 35 additional wild boar. PCV‐3 DNA was extracted and amplified with a conventional PCR. For the PCV‐3 PCR‐positive sera from the longitudinally sampled and different tissue types, a quantitative PCR was performed. Genome sequence was obtained from a number of PCV‐3 PCR‐positive samples from different years, different time‐points of infection and tissues. Obtained results confirmed the susceptibility of wild boar to the virus, showing high frequency of PCV‐3 detection (221 out of 518, 42.66%) and demonstrating circulation at least since 2004. Compiled data indicate the possibility of long‐term infections, since 5 out of 10 PCV‐3 PCR‐positive boars longitudinally sampled showed positivity in samplings separated for more than 5 months. All tested tissue types' harboured PCV‐3 genome, with the highest percentage of PCR positivity in submandibular lymph node, tonsil, lung, liver, spleen and kidney. The amount of DNA in all tested PCV‐3 PCR‐positive samples was moderate to low. All partial and complete PCV‐3 sequences obtained from wild boar displayed high nucleotide identity, higher than 98%. In conclusion, this study further confirms that wild boar is susceptible to PCV‐3 infection, showing high frequency of detection in this animal species. Furthermore, PCV‐3 can be found in different tissues of wild boar and is apparently able to cause persistent infection.Instituto Nacional de Investigación y Tecnologia Agraria y Alimentaria. Grant Number: E‐RTA2017‐00007‐00‐0
Influence of a commercial antithrombotic filter on the caval blood flow during neutra and valsalva maneuver
Anticoagulants are the treatment of choice for pulmonary embolism. When these fail or are contraindicated, vena cava filters are effective devices for preventing clots from the legs from migrating to the lung. Many uncertainties exist when a filter is inserted, especially during physiological activity such as normal breathing and the Valsalva maneuver. These activities are often connected with filter migration and vena cava damage due to the various related vein geometrical configurations. In this work, we analyzed the response of the vena cava during normal breathing and Valsalva maneuver, for a healthy vena cava and after insertion of a commercial Günther-Tulip® filter. Validated computational fluid dynamics (CFD) and patient specific data are used for analyzing blood flow inside the vena cava during these maneuvers. While during normal breathing, the vena cava flow can be considered almost stationary with a very low pressure gradient, during Valsalva the extravascular pressure compresses the vena cava resulting in a drastic reduction of the vein section, a global flow decrease through the cava but increasing the velocity magnitude. This change in the section is altered by the presence of the filter which forces the section of the vena cava before the renal veins to keep open. The effect of the presence of the filter is investigated during these maneuvers showing changes in wall shear stress and velocity patterns
A spectroscopic atlas of post-AGB stars and planetary nebulae selected from the IRAS Point Source Catalogue
Aims: We study the optical spectral properties of a sample of stars showing
far infrared colours similar to those of well-known planetary nebulae. The
large majority of them were unidentified sources or poorly known in the
literature at the time when this spectroscopic survey started, some 15 years
ago.
Methods: We present low-resolution optical spectroscopy, finding charts and
improved astrometric coordinates of a sample of 253 IRAS sources.
Results: We have identified 103 sources as post-AGB stars, 21 as ``transition
sources'', and 36 as planetary nebulae, some of them strongly reddened. Among
the rest of sources in the sample, we were also able to identify 38 young
stellar objects, 5 peculiar stars, and 2 Seyfert galaxies. Up to 49 sources in
our spectroscopic sample do not show any optical counterpart, and most of them
are suggested to be heavily obscured post-AGB stars, rapidly evolving on their
way to becoming planetary nebulae.
Conclusions: An analysis of the galactic distribution of the sources
identified as evolved stars in the sample is presented together with a study of
the distribution of these stars in the IRAS two-colour diagram. Finally, the
spectral type distribution and other properties of the sources identified as
post-AGB in this spectroscopic survey are discussed in the framework of stellar
evolution.Comment: 69 pages, 413 figures. Accepted by Astronomy and Astrophysic
Characterization and immunolocalization of RNA polymerase I transcription factor UBF with anti-NOR serum in protozoa, higher plant and vertebrate cells
We have used anti-NOR serum from a patient with rheumatoid arthritis, to study its reactivity on different phylogenetically separated species such as protozoa, higher plants, birds and mammals. The biochemical characteristics of the antigens detected after applying mono- and two-dimensional electrophoresis and electrophoretic transfers confirm that they correspond to the rRNA polymerase I transcription factor UBF. We have demonstrated the different molecular sizes, depending on the cell complexity, but the same neutral isoelectric points in whole cell extracts of the different species. We have also demonstrated an immunolocalization of this transcription factor to the fibrillar component in all the species studied. These results suggest a high conservation of UBF throughout evolution and the possibility of using this anti-NOR serum as a tool for the study of the structure, nucleolar organization and functional roles of the different nucleolar components
Aprendizaje autónomo basado en mecanismo de refuerzo aplicado a sistemas expertos legales
Este trabajo propone un modelo de aprendizaje que combina un refuerzo lineal aplicado a las ponderaciones asignadas a los atributos que caracterizan a un caso, con umbrales de decisión dinámicos que son ajustados a partir de casos almacenados en la base de conocimientos. La información incorporada a través de la interacción con el entorno permite mejorar la precisión de las recomendaciones emitidas por sistemas expertos.Eje: Inteligencia Computacional - MetaheurísticasRed de Universidades con Carreras en Informática (RedUNCI
A collimated, ionized bipolar structure and a high density torus in the young planetary nebula IRAS 17347-3139
We present observations of continuum (lambda = 0.7, 1.3, 3.6 and 18 cm) and
OH maser (lambda = 18 cm) emission toward the young planetary nebula IRAS
17347-3139, which is one of the three planetary nebulae that are known to
harbor water maser emission. From the continuum observations we show that the
ionized shell of IRAS 17347-3139 consists of two main structures: one extended
(size ~1". 5) with bipolar morphology along PA=-30 degrees, elongated in the
same direction as the lobes observed in the near-infrared images, and a central
compact structure (size ~0". 25) elongated in the direction perpendicular to
the bipolar axis, coinciding with the equatorial dark lane observed in the
near-infrared images. Our image at 1.3 cm suggests the presence of dense walls
in the ionized bipolar lobes. We estimate for the central compact structure a
value of the electron density at least ~5 times higher than in the lobes. A
high resolution image of this structure at 0.7 cm shows two peaks separated by
about 0". 13 (corresponding to 100-780 AU, using a distance range of 0.8-6
kpc). This emission is interpreted as originating in an ionized equatorial
torus-like structure, from whose edges the water maser emission might be
arising. We have detected weak OH 1612 MHz maser emission at VLSR ~ -70 km/s
associated with IRAS 17347-3139. We derive a 3 sigma upper limit of < 35% for
the percentage of circularly polarized emission. Within our primary beam, we
detected additional OH 1612 MHz maser emission in the LSR velocity ranges -5 to
-24 and -90 to -123 km/s, associated with the sources 2MASS J17380406-3138387
and OH 356.65-0.15, respectively.Comment: 26 pages, 8 figures. Accepted for publication in Ap
Simultaneous optimization of circadian and color performance for smart lighting systems design
We present in this work a method to design lighting sources that can be adapted to different temperatures of color and, simultaneously, with a tunable circadian character. We obtained an acceptable range of tuning in both parameters compared to the bibliography. This kind of lighting source has potential applications particularly in building lighting, but also in farming or agriculture. At the same time, we have shown the possibilities of multiobjective optimizations in the lighting industry. The optimization has been developed using the Genetic Algorithm and multiobjective merit functions. The lighting source is able to work under two different regimes regarding the circadian effect, with a design based on a combination of two monochromatic and two white Lighting Emitting Diodes (enough for controlling the circadian character and the color performance at the same time). A prototype, which can be manually or automatically controlled, has been also implemented and evaluated, with a performance in terms of color coordinates very close to the daylight, showing a modulation of the Circadian Efficacy of Radiation between 6% and 16%, and a Color Rendering Index above 80%
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