60 research outputs found
Use of digital platforms in English Language Teaching
The Foreign Language Department of the University of El Salvador introduced a specialization course designed for students of the Bachelor’s degree in English with an emphasis in teaching and the Bachelor´s degree in Modern Languages with an emphasis in French and English. They did it to provide the alternatives for undergraduate students to complete their graduation process. The authorities implemented a course to increase the knowledge and abilities of students about online teaching and learning. This report contains details on how the research team carried out activities and created material used during the course. Additionally, it shows the achievements they accomplished during the development of the specialization course and how they put into practice what they learned through online teaching and learning. Finally, the participants provide suggestions to improve teaching and learning quality at the Foreign Language Department of the School of Humanities.
Key words: E-learning ; Virtual learning ; Asynchronous and Synchronous Learning ; Online Teaching ; Flipped Learnin
HIV screening and retention in care in people who use drugs in Madrid, Spain: a prospective study
Background: The burden of human immunodeficiency virus (HIV) infection in people who use drugs (PWUD) is significant. We aimed to screen HIV infection among PWUD and describe their retention in HIV care. Besides, we also screen for hepatitis C virus (HCV) infection among HIV-seropositive PWUD and describe their linkage to care. Methods: We conducted a prospective study in 529 PWUD who visited the "Cañada Real Galiana" (Madrid, Spain). The study period was from June 1, 2017, to May 31, 2018. HIV diagnosis was performed with a rapid antibody screening test at the point-of-care (POC) and HCV diagnosis with immunoassay and PCR tests on dried blood spot (DBS) in a central laboratory. Positive PWUD were referred to the hospital. We used the Chi-square or Fisher's exact tests, as appropriate, to compare rates between groups. Results: Thirty-five (6.6%) participants were positive HIV antibodies, but 34 reported previous HIV diagnoses, and 27 (76%) had prior antiretroviral therapy. Among patients with a positive HIV antibody test, we also found a higher prevalence of homeless (P < 0.001) and injection drug use (PWID) (P < 0.001), and more decades of drug use (P = 0.002). All participants received HIV test results at the POC. Of the 35 HIV positives, 28 (80%) were retained in HIV medical care at the end of the HIV screening study (2018), and only 22 (62.9%) at the end of 2020. Moreover, 12/35 (34.3%) were positive for the HCV RNA test. Of the latter, 10/12 (83.3%) were contacted to deliver the HCV results test (delivery time of 19 days), 5/12 (41.7%) had an appointment and were attended at the hospital and started HCV therapy, and only 4/12 (33.3%) cleared HCV. Conclusions: We found almost no new HIV-infected PWUD, but their cascade of HIV care was low and remains a challenge in this population at risk. The high frequency of active hepatitis C in HIV-infected PWUD reflects the need for HCV screening and reinforcing the link to care.This work was funded by a research grant from Merck Sharpe & Dohme (Grant Number MISP IIS#54846) and Instituto de Salud Carlos III (ISCII; Grant Numbers PI20CIII/00004, and RD16CIII/0002/0002 to SR). The funders had no role in the study design, data collection, analysis, decision to publish, or preparation of the manuscript.S
All optical switching of a single photon stream by excitonic depletion
Single semiconductor quantum dots have been extensively used to demonstrate the deterministic emission of high purity single photons. The single photon emission performance of these nanostructures has become very well controlled, offering high levels of photon indistinguishability and brightness. Ultimately, quantum technologies will require the development of a set of devices to manipulate and control the state of the photons. Here we measure and simulate a novel all-optical route to switch the single photon stream emitted from the excitonic transition in a single semiconductor quantum dot. A dual non-resonant excitation pumping scheme is used to engineer a switching device operated with GHz speeds, high differential contrasts, ultra-low power consumption and high single photon purity. Our device scheme can be replicated in many different zero dimensional semiconductors, providing a novel route towards developing a platform-independent on-chip design for high speed and low power consumption quantum devices. Using semiconductor quantum dots as single-photon sources for application to quantum technologies is promising due to the high brightness and photon purity of the emitted light. Here, a method of optically switching their emission based on excitonic depletion is presented
Detection of active hepatitis C in a single visit and linkage to care among marginalized people using a mobile unit in Madrid, Spain
Background: The burden of hepatitis C virus (HCV) infection among marginalized people in Spain is high, despite the fact that HCV prevalence has decreased in recent years. We aimed to assess the effectiveness of a simplified point-of-care (PoC) model for screening for active HCV infection via a mobile unit and subsequent linkage to care with the assistance of navigators. Methods: We carried out a prospective study on 2001 participants from Madrid, Spain. A nurse and a navigator/educator screened for hepatitis C in a mobile unit, using the OraQuick HCV Rapid Antibody Test and Xpert HCV VL Fingerstick assay. Participants with active HCV were referred to the hospital the same day with a navigator for evaluation and treatment of HCV. Results: Overall, 1621 (81%) participants had not been exposed to HCV, 380 (18.9%) were positive for HCV antibodies, and 136 (6.8%) had active hepatitis C. Among the latter, 134 (98.5%) received the HCV screening results, 133 (97.8%) had an appointment at the hospital, 126 (92.8%) were seen by a physician once they were at the hospital, and 105 (77.2%) started HCV treatment. Being over 50 years old and a person who uses drugs, particularly people who inject drugs (PWID), was directly associated with active hepatitis C (p<0.05). PWID were the only patients with HCV reinfection (4.3% in people without recent injecting drug use and 5.9% in people with recent injecting drug use). Among PWID, no income and daily alcohol intake were also directly associated with active hepatitis C. People with recent injecting drug use showed the lowest rates of attendance at the hospital (91.8%) and starting HCV treatment (70.4%). Conclusion: HCV screening using a two-step PoC-based strategy and its linkage to care was extremely efficient for identifying and treating marginalized people with active hepatitis C, thanks to the use of a mobile unit with personnel and technical equipment, an interdisciplinary team, and collaboration between institutions.This work was funded by a research grant from Gilead Science (IN-ES-987-5391 and GLD20_0144) and Instituto de Salud Carlos III (ISCII; grant numbers PI20CIII/00004 and RD16CIII/0002/0002 to SR). It also received funding from AbbVie, Asociación Española para Estudio del Higado (AEEH), and Madrid Positivo Association.S
Time resolved emission at 1.3 micrometers of a single InAs quantum dot by using a tunable fibre Bragg grating
[EN] Photoluminescence and time resolved photoluminescence from single metamorphic
InAs/GaAs quantum dots (QDs) emitting at 1.3 micrometers have been measured by means of a novel
fibre-based characterization set-up. We demonstrate that the use of a wavelength tunable fibre
Bragg grating filter increases the light collection efficiency by more than one order of
magnitude as compared to a conventional grating monochromator. We identified single
charged exciton and neutral biexciton transitions in the framework of a random population
model. The QD recombination dynamics under pulsed excitation can be understood under the
weak quantum confinement potential limit and the interaction between carriers at the wetting
layer and QD states.G Munoz-Matutano appreciates valuable help from Professor Miguel Andres (University of Valencia) and thanks the Spanish Juan de la Cierva program (JCI-2011-10686). We acknowledge the support of the FEDER actions UPVOV08-3E-008 and UPVOV10-3E-492, the PROMETEO2009/74
project from Generalitat Valenciana, the Spanish projects TEC2011-29120-C05-01-02-05, the Italian FIRB
Project ‘Nanotecnologie e Nanodispositivi per la Societa` dell’Informazione’ and ‘SANDiE’ Network of Excellence of EC, Contract No. NMP4-CT-2004-500101.Muñoz Matutano, G.; Rivas, D.; Ricchiuti, AL.; Barrera Vilar, D.; Fernández Pousa, CR.; Martínez Pastor, J.; Seravalli, L.... (2014). Time resolved emission at 1.3 micrometers of a single InAs quantum dot by using a tunable fibre Bragg grating. Nanotechnology. 25(3):35204-1-35204-7. https://doi.org/10.1088/09574484/25/3/035204S35204-135204-725
The effect of high-In content capping layers on low-density bimodal-sized InAs quantum dots
[EN] The structural and morphological features of bimodal-sized InAs/(In) GaAs quantum dots with density in the low 10(9) cm(-2) range were analyzed with transmission electron microscopy and atomic force microscopy and were related to their optical properties, investigated with photoluminescence and time-resolved photoluminescence. We show that only the family of small quantum dots (QDs) is able to emit narrow photoluminescence peaks characteristic of single-QD spectra; while the behavior of large QDs is attributed to large strain fields that may induce defects affecting their optical properties, decreasing the optical intensity and broadening the homogeneous linewidth. Then, by using a rate-equation model for the exciton recombination dynamics, we show that thermal population of dark states is inhibited in both QD families capped by high In content InGaAs layers. We discuss this behavior in terms of alloy disorder and increased density of point defects in the InGaAs pseudomorphic layer.This work was supported through the Spanish MCINN and Generalitat Valenciana Grants Nos. TEC2011-29120-C05-01 and PROMETEO/2009/074, respectively, and by the 'SANDiE' Network of Excellence of EC, Contract No. NMP4-CT-2004-500101. AFM measurements were carried out at CIM-Parma University.Trevisi, G.; Suárez, I.; Seravalli, L.; Rivas, D.; Frigeri, P.; Muñoz Matutano, G.; Grillo, V.... (2013). The effect of high-In content capping layers on low-density bimodal-sized InAs quantum dots. Journal of Applied Physics. 113(19):1943061-1943068. https://doi.org/10.1063/1.4805351S1943061194306811319Salter, C. L., Stevenson, R. M., Farrer, I., Nicoll, C. A., Ritchie, D. A., & Shields, A. J. (2010). An entangled-light-emitting diode. Nature, 465(7298), 594-597. doi:10.1038/nature09078Faraon, A., Majumdar, A., Englund, D., Kim, E., Bajcsy, M., & Vučković, J. (2011). Integrated quantum optical networks based on quantum dots and photonic crystals. New Journal of Physics, 13(5), 055025. doi:10.1088/1367-2630/13/5/055025Ba Hoang, T., Beetz, J., Midolo, L., Skacel, M., Lermer, M., Kamp, M., … Fiore, A. (2012). Enhanced spontaneous emission from quantum dots in short photonic crystal waveguides. Applied Physics Letters, 100(6), 061122. doi:10.1063/1.3683541Joyce, P. B., Krzyzewski, T. J., Bell, G. R., Jones, T. S., Malik, S., Childs, D., & Murray, R. (2000). Effect of growth rate on the size, composition, and optical properties of InAs/GaAs quantum dots grown by molecular-beam epitaxy. Physical Review B, 62(16), 10891-10895. doi:10.1103/physrevb.62.10891Huang, S., Niu, Z., Ni, H., Xiong, Y., Zhan, F., Fang, Z., & Xia, J. (2007). Fabrication of ultra-low density and long-wavelength emission InAs quantum dots. Journal of Crystal Growth, 301-302, 751-754. doi:10.1016/j.jcrysgro.2006.11.299Trevisi, G., Seravalli, L., Frigeri, P., & Franchi, S. (2009). Low density InAs/(In)GaAs quantum dots emitting at long wavelengths. Nanotechnology, 20(41), 415607. doi:10.1088/0957-4484/20/41/415607Alloing, B., Zinoni, C., Zwiller, V., Li, L. H., Monat, C., Gobet, M., … Kapon, E. (2005). Growth and characterization of single quantum dots emitting at 1300 nm. Applied Physics Letters, 86(10), 101908. doi:10.1063/1.1872213Seravalli, L., Trevisi, G., Frigeri, P., Franchi, S., Geddo, M., & Guizzetti, G. (2009). The role of wetting layer states on the emission efficiency of InAs/InGaAs metamorphic quantum dot nanostructures. Nanotechnology, 20(27), 275703. doi:10.1088/0957-4484/20/27/275703Torchynska, T. V. (2008). Some aspects of exciton thermal exchange in InAs quantum dots coupled with InGaAs/GaAs quantum wells. Journal of Applied Physics, 104(7), 074315. doi:10.1063/1.2965196Nee, T.-E., Wu, Y.-F., Cheng, C.-C., & Shen, H.-T. (2006). Carrier dynamics study of the temperature- and excitation-dependent photoluminescence of InAs∕GaAs quantum dots. Journal of Applied Physics, 99(1), 013506. doi:10.1063/1.2150254Muñoz-Matutano, G., Suárez, I., Canet-Ferrer, J., Alén, B., Rivas, D., Seravalli, L., … Martínez-Pastor, J. (2012). Size dependent carrier thermal escape and transfer in bimodally distributed self assembled InAs/GaAs quantum dots. Journal of Applied Physics, 111(12), 123522. doi:10.1063/1.4729315Adhikary, S., Aytac, Y., Meesala, S., Wolde, S., Unil Perera, A. G., & Chakrabarti, S. (2012). A multicolor, broadband (5–20 μm), quaternary-capped InAs/GaAs quantum dot infrared photodetector. Applied Physics Letters, 101(26), 261114. doi:10.1063/1.4773373Krishna, S., Raghavan, S., von Winckel, G., Stintz, A., Ariyawansa, G., Matsik, S. G., & Perera, A. G. U. (2003). Three-color (λp1∼3.8 μm, λp2∼8.5 μm, and λp3∼23.2 μm) InAs/InGaAs quantum-dots-in-a-well detector. Applied Physics Letters, 83(14), 2745-2747. doi:10.1063/1.1615838Liu, H. Y., Hopkinson, M., Harrison, C. N., Steer, M. J., Frith, R., Sellers, I. R., … Skolnick, M. S. (2003). Optimizing the growth of 1.3 μm InAs/InGaAs dots-in-a-well structure. Journal of Applied Physics, 93(5), 2931-2936. doi:10.1063/1.1542914Seravalli, L., Trevisi, G., Frigeri, P., Rivas, D., Muñoz-Matutano, G., Suárez, I., … Martínez-Pastor, J. P. (2011). Single quantum dot emission at telecom wavelengths from metamorphic InAs/InGaAs nanostructures grown on GaAs substrates. Applied Physics Letters, 98(17), 173112. doi:10.1063/1.3584132Alloing, B., Zinoni, C., Li, L. H., Fiore, A., & Patriarche, G. (2007). Structural and optical properties of low-density and In-rich InAs∕GaAs quantum dots. Journal of Applied Physics, 101(2), 024918. doi:10.1063/1.2427104Seravalli, L., Trevisi, G., & Frigeri, P. (2012). Design and growth of metamorphic InAs/InGaAs quantum dots for single photon emission in the telecom window. CrystEngComm, 14(20), 6833. doi:10.1039/c2ce25860aGrillo, V., & Rossi, F. (2011). A new insight on crystalline strain and defect features by STEM–ADF imaging. Journal of Crystal Growth, 318(1), 1151-1156. doi:10.1016/j.jcrysgro.2010.10.180Grillo, V., Mueller, K., Volz, K., Glas, F., Grieb, T., & Rosenauer, A. (2011). Strain, composition and disorder in ADF imaging of semiconductors. Journal of Physics: Conference Series, 326, 012006. doi:10.1088/1742-6596/326/1/012006Lutz, M. A., Feenstra, R. M., Mooney, P. M., Tersoff, J., & Chu, J. O. (1994). Facet formation in strained Si1−x Gex films. Surface Science, 316(3), L1075-L1080. doi:10.1016/0039-6028(94)91208-4Kamins, T. I., Medeiros-Ribeiro, G., Ohlberg, D. A. A., & Stanley Williams, R. (1999). Evolution of Ge islands on Si(001) during annealing. Journal of Applied Physics, 85(2), 1159-1171. doi:10.1063/1.369255Kratzer, P., Liu, Q. K. K., Acosta-Diaz, P., Manzano, C., Costantini, G., Songmuang, R., … Kern, K. (2006). Shape transition during epitaxial growth ofInAsquantum dots onGaAs(001): Theory and experiment. Physical Review B, 73(20). doi:10.1103/physrevb.73.205347Grillo, V., & Rotunno, E. (2013). STEM_CELL: A software tool for electron microscopy: Part I—simulations. Ultramicroscopy, 125, 97-111. doi:10.1016/j.ultramic.2012.10.016Trevisi, G., Seravalli, L., Frigeri, P., Bocchi, C., Grillo, V., Nasi, L., … Martínez-Pastor, J. (2011). MBE growth and properties of low-density InAs/GaAs quantum dot structures. Crystal Research and Technology, 46(8), 801-804. doi:10.1002/crat.201000622Seravalli, L., Bocchi, C., Trevisi, G., & Frigeri, P. (2010). Properties of wetting layer states in low density InAs quantum dot nanostructures emitting at 1.3 μm: Effects of InGaAs capping. Journal of Applied Physics, 108(11), 114313. doi:10.1063/1.3518049Torchynska, T. V., Casas Espinola, J. L., Borkovska, L. V., Ostapenko, S., Dybiec, M., Polupan, O., … Malloy, K. J. (2007). Thermal activation of excitons in asymmetric InAs dots-in-a-well InxGa1−xAs∕GaAs structures. 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Exciton and multiexciton optical properties of single InAs/GaAs site-controlled quantum dots
[EN] We have studied the optical properties of InAs site-controlled quantum dots (SCQDs) grown on pre-patterned GaAs substrates. Since InAs nucleates preferentially on the lithography motifs, the location of the resulting QDs is determined by the pattern, which is fabricated by local oxidation nanolithography. Optical characterization has been performed on such SCQDs to study the fundamental and excited states. At the ground state different exciton complex transitions of about 500 μeV linewidth have been identified and the fine structure splitting of the neutral exciton has been determined (≈65 μeV). The observed electronic structure covers the demands of future quantum information technologiesThe authors want to acknowledge the financial support from Spanish government through grants QD-NANOTICS: TEC2011-29120-C05-01, EPIC-NANOTICS: TEC2011-29120-C05-04, PROMESA: ENE2012-37804-C02-02, and Q&C Light: S2009ESP-1503. We also thank the support from the PROMETEO2009/74 project (Generalitat Valenciana). J.C.-F. thanks the Spanish MCI for his FPI grant (No. BES-2006-12300) and J.H. acknowledges to the JAE program for the funds.Canet-Ferrer, J.; Muñoz Matutano, G.; Herranz, J.; Rivas, D.; Alén, B.; González, Y.; Fuster, D.... (2013). Exciton and multiexciton optical properties of single InAs/GaAs site-controlled quantum dots. Applied Physics Letters. 103(18). https://doi.org/10.1063/1.4828352S1031
Outcomes and effect of somatic mutations after erythropoiesis stimulating agents in patients with lower-risk myelodysplastic syndromes
Background: Erythropoiesis stimulating agents (ESAs) are the first-line therapy in patients with lower-risk myelodysplastic syndromes (LR-MDS). Some predictive factors for ESAs response have been identified. Type and number of somatic mutations have been associated with prognosis and response to therapies in MDS patients.Objectives: The objective was to evaluate the outcomes after ESAs in patients with LR-MDS and to address the potential predictive value of somatic mutations in ESAs-treated patients.Design: Multi-center retrospective study of a cohort of 722 patients with LR-MDS included in the SPRESAS (Spanish Registry of Erythropoietic Stimulating Agents Study) study. Retrospective analysis of 65 patients with next generation sequencing (NGS) data from diagnosis.Methods: ESAs' efficacy and safety were evaluated in patients receiving ESAs and best supportive care (BSC). To assess the potential prognostic value of somatic mutations in erythroid response (ER) rate and outcome, NGS was performed in responders and non-responders.Results: ER rate for ESAs-treated patients was 65%. Serum erythropoietin (EPO) level = 3; p = 0.170). The presence of >= 3 mutated genes was also significantly associated with worse OS (hazard ratio, 2.8; p= 0.015), even in responders. A higher cumulative incidence of acute myeloid leukemia progression at 5 years was also observed in patients with >= 3 mutated genes versus<3 (33.3% and 10.7%, respectively; p< 0.001).Conclusion: This large study confirms the beneficial effect of ESAs and the adverse effect of somatic mutations in patients with LR-MDS
UNIMINUTO: Cinco Años Cambiando Vidas en el Sur del país.
UNIMINUTO: Cinco años cambiando vidas en el sur del país, es
construido de manera colectiva por la Corporación Universitaria
Minuto de Dios a través del Centro Regional Neiva, sistematiza retos,
limitaciones, fortalezas y la prospectiva de la Universidad en el siglo
XXI desde los ejes de la docencia, la investigación y la proyección
social.
El texto contiene cuatro apartados y trece capítulos que dan cuenta
de los procesos investigativos adelantados en el Centro Regional,
aporta reflexiones en temas educativos, sociales, políticos, económicos
y psicológicos
.
Este libro ofrece al lector la posibilidad de pensar los retos que
presenta la Universidad en la formación de ciudadanos y ciudadanas
acordes a las realidades contemporáneas, logrando un despliegue
significativo de metodologías novedosas y pertinentes para el país y la
región Surcolombiana
UNIMINUTO: Cinco Años Cambiando Vidas en el Sur del país.
UNIMINUTO: Cinco años cambiando vidas en el sur del país, es
construido de manera colectiva por la Corporación Universitaria
Minuto de Dios a través del Centro Regional Neiva, sistematiza retos,
limitaciones, fortalezas y la prospectiva de la Universidad en el siglo
XXI desde los ejes de la docencia, la investigación y la proyección
social.
El texto contiene cuatro apartados y trece capítulos que dan cuenta
de los procesos investigativos adelantados en el Centro Regional,
aporta reflexiones en temas educativos, sociales, políticos, económicos
y psicológicos
.
Este libro ofrece al lector la posibilidad de pensar los retos que
presenta la Universidad en la formación de ciudadanos y ciudadanas
acordes a las realidades contemporáneas, logrando un despliegue
significativo de metodologías novedosas y pertinentes para el país y la
región Surcolombiana
- …