10,694 research outputs found

    Transient lateral photovoltaic effect in patterned metal-oxide-semiconductor films

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    The time dependent transient lateral photovoltaic effect has been studied with us time resolution and with chopping frequencies in the kHz range, in lithographically patterned 21 nm thick, 5, 10 and 20 um wide and 1500 um long Co lines grown over naturally passivated p-type Si (100). We have observed a nearly linear dependence of the transitorial response with the laser spot position. A transitorial response with a sign change in the laser-off stage has been corroborated by numerical simulations. A qualitative explanation suggests a modification of the drift-diffusion model by including the in uence of a local inductance. Our findings indicate that the microstructuring of position sensitive detectors could improve their space-time resolution.Comment: 4 pages, 4 figure

    Properties of aluminium nodules foamed with concentrated solar energy

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    Commercial aluminium foam filled structures and sandwich panels are available for structural applications. As alternative to these materials, small granular foamed pieces are proposed to fill structures as well as sandwich panels. On the present work, foam precursors are obtained by Powder Metallurgy (PM) route, using natural calcium carbonate as foaming agent instead of titanium hydride. Extruded precursor bars were cut into small pieces (around 4.5 mm long and 5mm in diameter). Foaming treatment was carried out on two different ways: electrical preheated furnace and by solar furnace. Foamed nodules presented a low cell size, density e.g. 0.67 g/cm3 to 0.88 g/cm3 and a height/diameter ratio between 0.72 and 0.84 as a function of precursor size. These properties depend on the foaming particle size, foaming cycle and precursor dimensions. Carbonate precursors are easily foamed by concentrated solar energy, due to the lower risk of cell collapse than with hydride precursors, resulting from cell stabilization by oxide skin formation into cells and a low degree of foamed nodules bonding

    Tratamiento térmico de espumación de precursores de aluminio-silicio en horno solar de lecho fluidificado

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    La fabricación de espumas de aluminio de poro cerrado mediante técnicas pulvimetalúrgias, conlleva una etapa de calentamiento del material (precursor) hasta su fusión y la formación de la espuma. En el presente trabajo, como continuación de los trabajos con energía solar concentrada aplicada directamente a la espumación de precursores Al10Si+0.8%TiH2, se han sometido al tratamiento de espumación en un horno solar de lecho fluidificado con el objetivo de obtener un tratamiento en volumen más homogéneo y uniforme, de manera que se puedan determinar la viabilidad del tratamiento, el procedimiento y los tiempos de residencia necesarios para llevar a cabo este proceso de manera discontinua o preindustrial. Así se han obtenido espumas 0,68 g/cm3 de densidad sin colapso de poros o decantación de aluminio, si bien como consecuencia del calentamiento preferencial por la base del molde, las espumas obtenidas presentan un tamaño de poro ligeramente más grande en la base de la espuma

    Preparation of Dipteran Larvae for Scanning Electron Microscopy with Special Reference to Myiasigen Dipteran Species

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    Although controversy exists concerning the role of chemical fixatives in scanning electron microscopy (SEM) studies of Dipteran larvae, we have observed that filtered 10% formaldehyde solution gives excellent results as a preservative. After immersing in vivo in formaldehyde, the larvae material is preserved for prolonged periods (up to 8 months), before examination with SEM. As a fixative, formaldehyde preserves the structure of the larval cuticle and produces no visible artifacts. Moreover, postfixation is not necessary. Due to pecularities of the way of life of Wohlfahrtia magnifica (principally the accumulations of necrotic tissue, purulent particles, and other types of substances that often adhere to the numerous spines of larvae), this species must be cleaned before examination by SEM. Manual cleaning with alternating bidistilled water and 0.9% saline solution proved to be a rapid, easy and inexpensive method that gave good results. Both lyophilization drying and critical point drying were used before sputtering the material. While lyophilization drying proved to be the most effective method for instars II and III, critical point drying was the best technique for study of specimens belonging to instar I. The optimum time for drying and conditions for lyophilization and sputter-coating with gold were determined experimentally. Samples were mounted on SEM stubs with double-sided adhesive and silver conductive paint. The method proposed is easy and effective for the SEM study of larvae myiasis-producing diptera

    Hickson-like compact groups inhabiting different environments

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    Although Compact Groups of galaxies (CGs) have been envisioned as isolated extremely dense structures in the Universe, it is accepted today that many of them could be not as isolated as thought. In this work, we study Hickson-like CGs identified in the Sloan Digital Sky Survey Data Release 16 to analyse these systems and their galaxies when embedded in different cosmological structures. To achieve this goal, we identify several cosmological structures where CGs can reside: Nodes of filaments, Loose Groups, Filaments and cosmic Voids. Our results indicate that 45 per cent of CGs do not reside in any of these structures, i.e., they can be considered non-embedded or isolated systems. Most of the embedded CGs are found inhabiting Loose Groups and Nodes, while there are almost no CGs residing well inside cosmic Voids. Some physical properties of CGs vary depending on the environment they inhabit. CGs in Nodes show the largest velocity dispersions, the brightest absolute magnitude of the first-ranked galaxy, and the smallest crossing times, while the opposite occurs in Non-Embedded CGs. When comparing galaxies in all the environments and galaxies in CGs, CGs show the highest fractions of red/early-type galaxy members in most of the absolute magnitudes ranges. The variation between galaxies in CGs inhabiting one or another environment is not as significant as the differences caused by belonging or not to a CG. Our results suggest a plausible scenario for galaxy evolution in CGs in which both, large-scale and local environments play essential roles.Comment: 16 pages, 9 figures, 1 table, accepted for publication in MNRA

    The Arabidopsis thioredoxin TRXh5regulates the S-nitrosylation pattern of the TIRK receptor being both proteins essential in the modulation of defences to Tetranychus urticae

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    The interaction between plants and phytophagous arthropods encompasses a complex network of molecules, signals, and pathways to overcome defences generated by each interacting organism. Although most of the elements and modulators involved in this interplay are still unidentified, plant redox homeostasis and signalling are essential for the establishment of defence responses. Here, focusing on the response of Arabidopsis thaliana to the spider mite Tetranychus urticae, we demonstrate the involvement in plant defence of the thioredoxin TRXh5, a small redox protein whose expression is induced by mite infestation. TRXh5 is localized in the cell membrane system and cytoplasm and is associated with alterations in the content of reactive oxygen and nitrogen species. Protein S-nitrosylation signal in TRXh5 over-expression lines is decreased and alteration in TRXh5 level produces changes in the JA/SA hormonal crosstalk of infested plants. Moreover, TRXh5 interacts and likely regulates the redox state of an uncharacterized receptor-like kinase, named THIOREDOXIN INTERACTING RECEPTOR KINASE (TIRK), also induced by mite herbivory. Feeding bioassays performed withTRXh5 over-expression plants result in lower leaf damage and reduced egg accumulation after T. urticae infestation than in wild-type (WT) plants. In contrast, mites cause a more severe injury in trxh5 mutant lines where a greater number of eggs accumulates. Likewise, analysis of TIRK-gain and -loss-of-function lines demonstrate the defence role of this receptor in Arabidopsis against T. urticae. Altogether, our findings demonstrate the interaction between TRXh5 and TIRK and highlight the importance of TRXh5 and TIRK in the establishment of effective Arabidopsis defences against spider mite herbivory.Grants PID2020-115219RB-I00, RED2018-102397-T and RyC17MESFB funded by MCIN/AEI/10.13039/501100011033, as appropriate, by “ERDF A way of making Europe” and by the “European Union” supported this work. Grants, SIMQG-263-1HWZ8Q UPM-Banco Santander Universidades, RyC2017-21814 and PRE2018-083375 from MCIN/AEI supported AA, MES and IRD, respectively. The Spanish Ministry of Science and Innovation (MCIN), the State Research Agency (AEI) and the European Regional Development Fund (ERDF; grant MEC-PID2021-122280NB-I00) financed MCRP and LMS. The Government of Canada through the Ontario Research Fund (RE08-067) and the Natural Sciences and Engineering Research Council of Canada (NSERC, RGPIB-2018-04538) supported VG

    Los sistemas de escritura coreanos : del préstamo a la escritura propia

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    El sistema de escritura de los coreanos es el hangul pero, ¿fue siempre así? En este trabajo veremos que siglos atrás usaron los caracteres chinos como sistema de escritura. Pero pronto desarrollarán tres sistemas propios basados en estos últimos: el hyangchal, el kugyol y el idu, siendo este último el más duradero junto con la escritura mixta, surgida de la mezcla entre el hangul y los caracteres chinos. El sistema de escritura de los coreanos es el hangul pero, ¿fue siempre así? En este trabajo veremos que siglos atrás usaron los caracteres chinos como sistema de escritura. Pero pronto desarrollarán tres sistemas propios basados en estos últimos: el hyangchal, el kugyol y el idu, siendo este último el más duradero junto con la escritura mixta, surgida de la mezcla entre el hangul y los caracteres chinosThe writing system of Korean people is hangul but, has always been so? On this work we will find out that centuries ago they used Chinese characters as writing system. But soon they will develop their own three systems based on these last ones: hyangchal, kugyol and idu, being this last one the most durable along with the mixed script, emerged between the mix of hangul and Chinese characters. The writing system of Korean people is hangul but, has always been so? On this work we will find out that centuries ago they used Chinese characters as writing system. But soon they will develop their own three systems based on these last ones: hyangchal, kugyol and idu, being this last one the most durable along with the mixed script, emerged between the mix of hangul and Chinese character

    New Clues About Light Sterile Neutrinos: Preference for Models with Damping Effects in Global Fits

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    This article reports global fits of short-baseline neutrino data to oscillation models involving light sterile neutrinos. In the commonly-used 3+1 plane wave model, there is a well-known 4.9σ\sigma tension between data sets sensitive to appearance and disappearance of neutrinos. We find that models that damp the oscillation prediction for the reactor data sets, especially at low energy, substantially improve the fits and reduce the tension. We consider two such scenarios. The first introduces one sterile neutrino (3+1) and the Quantum Mechanical wavepacket effect that accounts for the source size in reactor experiments. We find that inclusion of the wavepacket effect greatly improves the overall fit compared to the null model by Δχ2/dof=60.2/4\Delta \chi^2/\textrm{dof}=60.2/4 (7σ7\sigma improvement) with best-fit Δm2=1.4 eV2\Delta m^2=1.4~\textrm{eV}^2 and wavepacket length of 67 fm; internal tension is reduced to 3.6σ\sigma. If reactor-data only is fit, that the wavepacket preferred length is 91 fm (>20>20 fm at 99\% CL). The second model introduces oscillations involving sterile flavor and allows the decay of the heavier, mostly sterile, mass state ν4\nu_4. This model introduces a damping term similar to the wavepacket effect, but across all experiments. Compared to null, this has a Δχ2/dof=60.6/4\Delta \chi^2/\textrm{dof}=60.6/4 (7σ7\sigma improvement) with preferred Δm2=1.4 eV2\Delta m^2=1.4~\textrm{eV}^2 and decay Γ=0.35 eV\Gamma = 0.35~\textrm{eV}; and internal tension of 3.7σ\sigma.Comment: Errors are the prospect plot updated from the collaboration. Tension figures have updated plot styl

    Validation of whole-slide imaging in the primary diagnosis of liver biopsies in a University Hospital

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    BACKGROUND: Experience in the use of whole slide imaging (WSI) for primary diagnosis is limited and there are no comprehensive reports evaluating this technology in liver biopsy specimens. AIMS: To determine the accuracy of interpretation of WSI compared with conventional light microscopy (CLM) in the diagnosis of needle liver biopsies. METHODS: Two experienced liver pathologists blindly analyzed 176 consecutive biopsies from the Pathology Department at the Hospital Clinic of Barcelona. One of the observers performed the initial evaluation with CLM, and the second evaluation with WSI, whereas the second observer performed the first evaluation with WSI and the second with CLM. All slides were digitized in a Ventana iScan HT at 400x and evaluated with the Virtuoso viewer (Roche diagnostics). We used kappa statistics (kappa) for two observations. RESULTS: Intra-observer agreement between WSI and CLM evaluations was almost perfect (96.6%, kappa=0.9; 95% confidence interval [95% CI]: 0.9-1 for observer 1, and 90.3%, kappa=0.9; 95%CI: 0.8-0.9 for observer 2). Both native and transplantation biopsies showed an almost perfect concordance in the diagnosis. CONCLUSION: Diagnosis of needle liver biopsy specimens using WSI is accurate. This technology can reliably be introduced in routine diagnosis
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