1,454 research outputs found

    Inducing nonclassical lasing via periodic drivings in circuit quantum electrodynamics

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    We show how a pair of superconducting qubits coupled to a microwave cavity mode can be used to engineer a single-atom laser that emits light into a nonclassical state. Our scheme relies on the dressing of the qubit-field coupling by periodic modulations of the qubit energy. In the dressed basis, the radiative decay of the first qubit becomes an effective incoherent pumping mechanism that injects energy into the system, hence turning dissipation to our advantage. A second, auxiliary qubit is used to shape the decay within the cavity, in such a way that lasing occurs in a squeezed basis of the cavity mode. We characterize the system both by mean-field theory and exact calculations. Our work may find applications in the generation of squeezing and entanglement in circuit QED, as well as in the study of dissipative few- and many-body phase transitions

    Symbiotic Stars in OGLE Data I. Large Magellanic Cloud Systems

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    Symbiotic stars are long-orbital-period interacting-binaries characterized by extended emission over the whole electromagnetic range and by complex photometric and spectroscopic variability. In this paper, the first of a series, we present OGLE light curves of all the confirmed symbiotic stars in the Large Magellanic Cloud, with one exception. By careful visual inspection and combined time-series analysis techniques, we investigate for the first time in a systematic way the photometric properties of these astrophysical objects, trying in particular to distinguish the nature of the cool component (e.g., Semi-Regular Variable vs. OGLE Small-Amplitude Red Giant), to provide its first-order pulsational ephemerides, and to link all this information with the physical parameters of the binary system as a whole. Among the most interesting results, there is the discovery of a 20-year-long steady fading of Sanduleak's star, a peculiar symbiotic star known to produce the largest stellar jet ever discovered. We discuss by means of direct examples the crucial need for long-term multi-band observations to get a real understanding of symbiotic and other interacting binary stars. We eventually introduce BOMBOLO, a multi-band simultaneous imager for the SOAR 4m Telescope, whose design and construction we are currently leading.Comment: 16 pages, 4 Tables, 12 Figures. Accepted for publication in MNRA

    Evaluating the capacity of human gut microorganisms to colonize the zebrafish larvae (Danio rerio)

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    Indexación: Scopus.In this study we evaluated if zebrafish larvae can be colonized by human gut microorganisms. We tested two strategies: (1) through transplantation of a human fecal microbiota and (2) by successively transplanting aerotolerant anaerobic microorganisms, similar to the colonization in the human intestine during early life. We used conventionally raised zebrafish larvae harboring their own aerobic microbiota to improve the colonization of anaerobic microorganisms. The results showed with the fecal transplant, that some members of the human gut microbiota were transferred to larvae. Bacillus, Roseburia, Prevotella, Oscillospira, one unclassified genus of the family Ruminococcaceae and Enterobacteriaceae were detected in 3 days post fertilization (dpf) larvae; however only Bacillus persisted to 7 dpf. Successive inoculation of Lactobacillus, Bifidobacterium and Clostridioides did not improve their colonization, compared to individual inoculation of each bacterial species. Interestingly, the sporulating bacteria Bacillus clausii and Clostridioides difficile were the most persistent microorganisms. Their endospores persisted at least 5 days after inoculating 3 dpf larvae. However, when 5 dpf larvae were inoculated, the proportion of vegetative cells in larvae increased, revealing proliferation of the inoculated bacteria and better colonization of the host. In conclusion, these results suggest that it is feasible to colonize zebrafish larvae with some human bacteria, such as C. difficile and Bacillus and open an interesting area to study interactions between these microorganisms and the host. © 2018 Valenzuela, Caruffo, Herrera, Medina, Coronado, Feijóo, Muñoz, Garrido, Troncoso, Figueroa, Toro, Reyes-Jara, Magne and Navarrete.https://www.frontiersin.org/articles/10.3389/fmicb.2018.01032/ful

    Impact of Procedure Manual in a Cleaning Company

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    This project is developed in a cleaning company, which we will call "Clean Express" to maintain the anonymity of the same, said company is located Boca del Rio, Veracruz, Mexico. According to Gido in 2012, the case study company has a functional type structure because the departments group the areas

    Simulating quantum-optical phenomena with cold atoms in optical lattices

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    We propose a scheme involving cold atoms trapped in optical lattices to observe different phenomena traditionally linked to quantum-optical systems. The basic idea consists of connecting the trapped atomic state to a non-trapped state through a Raman scheme. The coupling between these two types of atoms (trapped and free) turns out to be similar to that describing light-matter interaction within the rotating-wave approximation, the role of matter and photons being played by the trapped and free atoms, respectively. We explain in particular how to observe phenomena arising from the collective spontaneous emission of atomic and harmonic oscillator samples such as superradiance and directional emission. We also show how the same setup can simulate Bose-Hubbard Hamiltonians with extended hopping as well as Ising models with long-range interactions. We believe that this system can be realized with state of the art technology

    Condensed tannin reactivity inhibition by internal rearrangements: Detection by CP-MAS 13C NMR

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    Tannin extracts were prepared from barks of maritime pine (Pinus maritimus), aleppo pine (Pinus halepensis), Norway spruce (Picea abies) and from a mixture of barks of different pine species (Pinus spp., namely 20% black pine (Pinus thunbergii)+ 30% Scots pine (Pinus sylvestris) + 20% maritime pine (Pinus maritimus) + 10% Aleppo Pine (Pinus halepensis) + 5% Douglas fir (Pseudotsuga menziesii) + 15% Norway spruce (Picea abies)) at a paper mill. The 13C-NMR spectra were carried out from these tannins. Blending systems adhesives were prepared with 5% paraformaldehyde to measure the reactivity by gel time, and to determinate the mechanical resistance by thermomechanical analysis (TMA) and the internal bond strength (IB) according to the European Norm EN-312. The CP MAS 13C NMR bands at 163 ppm and the increase number of smaller bands between 20 and 65 ppm clearly indicate that the extraction of procyanidin-type tannins has been incorrect yielded high relative proportions of catechinic acid structures and diarylpropanol-catechinin acid dimer caused by internal flavonoid rearrangement, and causing the blockage of the C6 and C8 reactive sites, rendering unusable the tannin for wood adhesive applications. Thus, the gel times are very long except for the maritime pine tannin with a value of 51 (s). The TMA analysis gave very low MOE values for almost all the tannin extract samples, except for maritime pine. This situation was confirmed by the IB test. Only maritime pine tannin presented a good mechanical resistance with a value of 0.6 (MPa). Only this sample fulfils the standard requested

    Ensayos para rehabilitación de obras de tierra (adobe, tapial)

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    Resulta patente la necesidad de instaurar una serie de criterios generales que permitan afrontar de un modo normalizado la rehabilitación y construcción de obras ejecutadas con muros de tierra, principalmente adobe y tapial. Con el fin de fomentar la correcta ejecución de estos sistemas constructivos que han dado lugar a notables monumentos a lo largo de la Historia y reconducir procesos anárquicos de autoconstrucción como los que se producen en numerosas zonas de Hispanoamérica. Se pretende desarrollar un estudio de los ensayos geotécnicos que pueden ser aplicables a esta condición estructural de la tierra. Seleccionando aquellos que permitan obtener datos eficientes para una posterior modelización del edificio, calculado mediante programas informáticos de elementos finitos. Basándonos en experiencias previas y en estudios experimentales propios, como el efectuado en la “Hacienda del Quinto”, ubicada en Dos Hermanas (Sevilla). Pretendemos aportar nuevos criterios que completen la elaboración de una futura “Guía para construcción y rehabilitación de obras de tierra”, con el fin de sentar las bases germinales de una normativa nacional sobre muros de tierra, actualmente inexistente.Universidad de Las Palmas de Gran CanariaColegio Oficial de Ingenieros Industriales de CanariasAgencia Canaria de Investigación, Innovación y Sociedad de la Informació

    Pilot Study on the Efficiency of the Biostimulation with Autologous Plasma Rich in Platelet Growth Factors in Otorhinolaryngology: Otologic Surgery (Tympanoplasty Type I)

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    When otologic procedures that involve tympanic membrane repairs are performed, biomaterials or biological tissues as normal as grafts are used. At the moment, biological material from the own patient is used with varying success rates. The procedure used and the patient's tissue repair capabilities tend to determine the outcome. We present a preliminary study on tympanic membrane perforation repairs using an autograft obtained by manipulating platelet degranulation and the coagulation cascade and reinforced with a seal using platelet growth factors. We present three cases in which we used this procedure. The results will be valued based on the tympanic perforation closure index. With this study, we want to assess the effectiveness of tympanic perforation repairs with this technically simple method. If this method was objectively proved to be effective, it would lead to lower patient morbidity and sanitary costs

    Functional human sperm capacitation requires both bicarbonate dependent-PKA activation and down-regulation of Ser/Thr phosphatases by Src family kinases

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    In all mammalian species studied so far, sperm capacitation correlates with an increase in protein tyrosine (Tyr) phosphorylation mediated by a bicarbonate-dependent cAMP/PKA pathway. Recent studies in mice revealed however that a Src Family Kinase (SFK) induced inactivation of serine/threonine (Ser/Thr) phosphatases is also involved in the signaling pathways leading to Tyr phosphorylation. In view of these observations and with the aim of getting a better understanding of the signaling pathways involved in human sperm capacitation, in the present work we investigated the involvement of both the cAMP/PKA and SFK/phosphatase pathways in relation to the capacitation state of the cells. For this purpose, different signaling events and sperm functional parameters were analyzed as a function of capacitation time. Results revealed a very early bicarbonate-dependent activation of PKA indicated by the rapid (1 min) increase in both phospho-PKA substrates and cAMP levels (p<0.05). However, a complete pattern of Tyr phosphorylation was detected only after 6 h-incubation at which time sperm exhibited the ability to undergo the acrosome reaction (AR) and to penetrate zona-free hamster eggs. Sperm capacitated in the presence of the SFK inhibitor SKI606 showed a decrease in both PKA substrate and Tyr phosphorylation levels which was overcome by exposure of sperm to the Ser/Thr phosphatase inhibitor okadaic acid (OA). However, OA was unable to induce phosphorylation when sperm were incubated under PKA-inhibitory conditions (i.e. in the absence of bicarbonate or presence of PKA inhibitor). Moreover, the increase in PKA activity by exposure to a cAMP analogue and a phosphodiesterase inhibitor did not overcome the inhibition produced by SKI606. Whereas the presence of SKI606 during capacitation produced a negative effect (p<0.05) on sperm motility, progesterone-induced AR and fertilizing ability, none of these inhibitions were observed when sperm were exposed to SKI606 and OA. Interestingly, different concentrations of inhibitors were required to modulate human and mouse capacitation revealing the species-specificity of the molecular mechanisms underlying this process. In conclusion, our results describe for the first time the involvement of both PKA activation and Ser/Thr phosphatase down-regulation in functional human sperm capacitation and provide convincing evidence that early PKA-dependent phosphorylation is the convergent regulatory point between these two signaling pathways.Fil: Battistone, Maria Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas -conicet. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Da Ros, Vanina Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas -conicet. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Salicioni, A.. University Of Massachussets; Estados UnidosFil: Navarrete, F.. University Of Massachussets; Estados UnidosFil: Krapf, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Rosario. Instituto de Biología Molecular y Celular de Rosario; Argentina. Universidad Nacional de Rosario; ArgentinaFil: Visconti, P. E.. University Of Massachussets;Fil: Cuasnicu, Patricia Sara. Consejo Nacional de Investigaciones Científicas y Técnicas -conicet. Instituto de Biología y Medicina Experimental (i); Argentin
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