2,715 research outputs found

    Continuous spectra in high-harmonic generation driven by multicycle laser pulses

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    We present observations of the emission of XUV continua in the 20-37 eV region by high harmonic generation (HHG) with 44-7 fs7\ \mathrm{fs} pulses focused onto a Kr gas jet. The underlying mechanism relies on coherent control of the relative delays and phases between individually generated attosecond pulse, achievable by adjusting the chirp of the driving pulses and the interaction geometry. Under adequate negative chirp and phase matching conditions, the resulting interpulse interference yields a continuum XUV spectrum, which is due to both microscopic and macroscopic (propagation) contributions. This technique opens the route for modifying the phase of individual attosecond pulses and for the coherent synthesis of XUV continua from multicycle driving laser pulses without the need of an isolated attosecond burst.Comment: 14 pages, 5 figures. Submitted to Physical Review

    Human Interaction in Learning Ecosystems based on Open Source Solutions

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    Technological ecosystems are software solutions based on the integration of heterogeneous software components through information flows in order to provide a set of services that each component separately does not offer, as well as to improve the user experience. In particular, the learning ecosystems are technological ecosystems focused on learning and knowledge management in different contexts such as educational institutions or companies. The ecosystem metaphor comes from biology field and it has transferred to technology field to highlight the evolving component of software. Taking into account the definitions of natural ecosystems, a technological ecosystem is a set of people and software components that play the role of organisms; a series of elements that allow the ecosystem works (hardware, networks, etc.); and a set of information flows that establish the relationships between the software components, and between these and the people involved in the ecosystem. Human factor has a main role in the definition and development of this kind of solutions. In previous works, a metamodel has been defined and validated to support Model-Driven Development of learning ecosystems based on Open Source software, but the interaction in the learning ecosystem should be defined in order to complete the proposal to improve the development process of technological ecosystems. This paper presents the definition and modelling of the human interaction in learning ecosystem

    Desarrollo micelial y formación de basidiomas de Pleurotus eryngii (DC.) Quél. Pleurotaceae, Basidiomycete

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    El objetivo del presente trabajo fue evaluar el desarrollo micelial e incremento de biomasa en diferentes medios de cultivo como Papa dextrosa (PDA), Extracto de Malta (EM), Bebida de Malta (BM), Harina de Maíz (HM) y Harina de Quinua (HQ) y en granos de trigo para la obtención del inoculo fúngico y formación de basidiomas. Se utilizaron indicadores como la Tasa de Crecimiento Diario (TCD) y el Incremento de Biomasa (IB) tomando en cuenta la TCD volumétrico (TCDv). El medio de cultivo casero con mejores resultados fue el basado en Harina de Maíz (HM), con una TCD de 9.79 mm/día y un incremento de biomasa de 0.1325 g en 8 días. Respecto al incremento de biomasa en granos de trigo, los mejores resultados se obtuvieron a una temperatura de incubación de 24 °C, con una TCDv de 1004 mm3/día. Los basidiomas se desarrollaron en granos de trigo alcanzando píleos de 3.2 – 9.2 cm de diámetro y estípite de 3 – 8 x 1.2 – 3.6 cm. los mismos que presentaron un alto contenido de proteínas (24.46 %), carbohidratos (53.14%) y fibra (27.8%)

    Integrated slot-waveguide microresonator for biochemical sensing

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    A novel integrated biochemical sensor based on a slot-waveguide [1] microring resonator is demonstrated. The microresonator is fabricated on a Si3N4/SiO2 material platform [2] by using conventional microfabrication techniques, such as Si thermal oxidation, chemical vapour deposition, electron-beam lithography and reactive ion etching. The sensor consists of a 70-μm-radius ring resonator formed by a slot-waveguide [1] having a slot-width of 200 nm. The operation wavelength is 1.3 μm. The device is exposed to different water-ethanol solutions and its transmission spectrum is measured. A linear shift of the resonant wavelength with increasing ambient refractive index of 212 nm/refractive index units (RIU) is observed. This value is more than twice larger than those of strip-waveguide ring resonator biochemical sensors, indicating that higher analyte-probe light interaction occurs in our slot-waveguide sensor as compared to those based on conventional strip waveguides. The sensor detects a minimal refractive index variation of 2x10-4 RIU, limited by the wavelength resolution of the light source (50 pm). Simulations indicate that the slot region is partially filled when the sensor is exposed to an aqueous solution. We also demonstrate the capability of our sensor to measure higher index fluids such as isopropanol (n=1.37) and cyclohexane (n=1.42)

    Tomosyn inhibits synaptic vesicle priming in Caenorhabditis elegans

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    Caenorhabditis elegans TOM-1 is orthologous to vertebrate tomosyn, a cytosolic syntaxin-binding protein implicated in the modulation of both constitutive and regulated exocytosis. To investigate how TOM-1 regulates exocytosis of synaptic vesicles in vivo, we analyzed C. elegans tom-1 mutants. Our electrophysiological analysis indicates that evoked postsynaptic responses at tom-1 mutant synapses are prolonged leading to a two-fold increase in total charge transfer. The enhanced response in tom-1 mutants is not associated with any detectable changes in postsynaptic response kinetics, neuronal outgrowth, or synaptogenesis. However, at the ultrastructural level, we observe a concomitant increase in the number of plasma membrane-contacting vesicles in tom-1 mutant synapses, a phenotype reversed by neuronal expression of TOM-1. Priming defective unc-13 mutants show a dramatic reduction in plasma membrane-contacting vesicles, suggesting these vesicles largely represent the primed vesicle pool at the C. elegans neuromuscular junction. Consistent with this conclusion, hyperosmotic responses in tom-1 mutants are enhanced, indicating the primed vesicle pool is enhanced. Furthermore, the synaptic defects of unc-13 mutants are partially suppressed in tom-1 unc-13 double mutants. These data indicate that in the intact nervous system, TOM-1 negatively regulates synaptic vesicle priming. © 2006 Gracheva et al

    Innovación en el diseño de centrales hidroeléctricas a principios de siglo XX. La ingeniería arquitectura de Casto Fernández-Shaw en la presa de La Jándula

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    The power plant location in the first hydroelectrial dams was a relevant issue at the end of XIX century and early XX. Different solutions were tried, some of them with very interesting aesthetics results and hydraulic and structural implications. Such is the case of La Jándula dam, inaugurated in 1930, that includes the power station inside the dam. This article examines the possible national and international inspirations of this singular solution, corroborating the hypothesis of its unprecedented nature. The collaboration of the architect Casto Fernández-Shaw in the design and integration of the engine room was decisive, because it achieved a result of an aesthetic quality and formal expressiveness unprecedented in a work of hydraulic engineering, as well as the birth of a style Shaw himself defined as architectural engineering.La ubicación de la sala de máquinas fue un factor relevante en las primeras presas hidroeléctricas de finales del siglo XIX y principios del XX, que originó el ensayo de distintas soluciones, algunas de ellas con resultados estéticos e implicaciones hidráulicas y estructurales de gran interés. Tal es el caso de la presa de La Jándula, inaugurada en 1930, que incorporaba la central en el seno del cuerpo de presa. El artículo indaga los posibles antecedentes nacionales e internacionales de esta solución tan singular, corroborando la hipótesis de su carácter inédito. La colaboración del arquitecto Casto Fernández- Shaw en el diseño e integración de la sala de máquinas fue decisiva, ya que logró un resultado de una calidad estética y una expresividad formal sin precedentes en una obra de ingeniería hidráulica, así como el nacimiento de un estilo que el propio Shaw definiría como ingeniería arquitectura

    Label-free optical biosensing with slot-waveguides.

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    We demonstrate label-free molecule detection by using an integrated biosensor based on a Si3N4 /SiO2 slotwaveguide microring resonator. Bovine serum albumin (BSA) and anti-BSA molecular binding events on the sensor surface are monitored through the measurement of resonant wavelength shifts with varying biomolecule concentrations. The biosensor exhibited sensitivities of 1.8 and 3.2 nm/ _ng/mm2_ for the detection of anti-BSA and BSA, respectively. The estimated detection limits are 28 and 16 pg/mm2 for anti-BSA and BSA, respectively, limited by wavelength resolutio

    Silicon nanopillar arrays with SiO2 overlayer for biosensing application

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    We present the fabrication of silicon dioxide (SiO2) coated silicon nanopillar array structures and demonstrate their application as sensitive optical biosensors. Colloidal lithography, plasma dry etching and deposition processes are used to fabricate SiO2 coated Si nanopillar arrays with two different diameters and periods. Proof of concept bio recognition experiments are carried out with the bovine serum albumin (BSA)/antiBSA model system using Fourier transform visible and IR spectrometry (FT-VIS-IR) in reflection mode. A limit of detection (LoD) value of 5.2 ng/ml is estimated taking in to account the wavenumber uncertainty in the measurements

    An Unusual Metastatic Renal Cell Carcinoma with Maintained Complete Response to Sunitinib Treatment

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    Recently, metastatic renal cell carcinoma (mRCC) treatment has changed dramatically with the onset of new therapies against molecular targets replacing immunotherapy as standard treatment. We report the case of a 49-year-old patient with a moderately differentiated renal clear cell carcinoma without extracapsular extension who underwent radical nephrectomy. Eight months after surgery, he developed a thyroid metastasis which was also treated surgically with a hemithyroidectomy. Seventy-five months after nephrectomy, the patient presented an upper gastrointestinal bleeding due to a duodenal metastasis that infiltrates the head of the pancreas. The treatment applied was surgery by duodenopancreatectomy, with positive surgical margins in the pathologic study. In addition to this, the extension study showed lung metastases requiring initiation of systemic treatment with sunitinib. The patient presented an excellent response to treatment, showing complete clinical and radiological response at 5 months of treatment (RECIST criteria) and a disease-free survival of 48 months until now, without evidence of toxicity. RCC has the potential to metastasize to almost any location, but thyroid and duodenal metastases in RCC are extremely rare. Moreover, this case also highlights the good responses that can be achieved in terms of disease-free survival, low toxicity and quality of life in this new era of therapies against molecular targets
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