3,618 research outputs found

    Spontaneous patterns in coherently driven polariton microcavities

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    We consider a polariton microcavity resonantly driven by two external lasers which simultaneously pump both lower and upper polariton branches at normal incidence. In this setup, we study the occurrence of instabilities of the pump-only solutions towards the spontaneous formation of patterns. Their appearance is a consequence of the spontaneous symmetry breaking of translational and rotational invariance due to interaction induced parametric scattering. We observe the evolution between diverse patterns which can be classified as single-pump, where parametric scattering occurs at the same energy as one of the pumps, and as two-pump, where scattering occurs at a different energy. For two-pump instabilities, stripe and chequerboard patterns become the dominant steady-state solutions because cubic parametric scattering processes are forbidden. This contrasts with the single-pump case, where hexagonal patterns are the most common arrangements. We study the possibility of controlling the evolution between different patterns. Our results are obtained within a linear stability analysis and are confirmed by finite size full numerical calculations.Comment: 15 pages, 9 figure

    LAGOVirtual: A Collaborative Environment for the Large Aperture GRB Observatory

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    We present the LAGOVirtual Project: an ongoing project to develop platform to collaborate in the Large Aperture GRB Observatory (LAGO). This continental-wide observatory is devised to detect high energy (around 100 GeV) component of Gamma Ray Bursts, by using the single particle technique in arrays of Water Cherenkov Detectors (WCD) at high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). This platform will allow LAGO collaboration to share data, and computer resources through its different sites. This environment has the possibility to generate synthetic data by simulating the showers through AIRES application and to store/preserve distributed data files collected by the WCD at the LAGO sites. The present article concerns the implementation of a prototype of LAGO-DR adapting DSpace, with a hierarchical structure (i.e. country, institution, followed by collections that contain the metadata and data files), for the captured/simulated data. This structure was generated by using the community, sub-community, collection, item model; available at the DSpace software. Each member institution-country of the project has the appropriate permissions on the system to publish information (descriptive metadata and associated data files). The platform can also associate multiple files to each item of data (data from the instruments, graphics, postprocessed-data, etc.).Comment: Second EELA-2 Conference Choroni, Venezuela, November 25th to 27th 200

    The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City

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    <p>Abstract</p> <p>Background</p> <p><it>Culex </it>spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, <it>Culex pipiens pipiens, Culex pipiens quinquefasciatus</it>, and <it>Culex tarsalis </it>are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of <it>Culex pipiens </it>complex mosquitoes and hybrids in Mexico City. <it>Culex pipiens pipiens </it>preferentially feed on avian hosts; <it>Culex pipiens quinquefasciatus </it>have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of <it>Culex pipiens </it>complex mosquitoes and their hybrids.</p> <p>Results</p> <p>Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as <it>Culex, Culiseta </it>or <it>Ochlerotatus </it>by morphological analysis. Within the genus <it>Culex</it>, specimens were further identified as <it>Culex tarsalis </it>or as belonging to the <it>Culex pipiens </it>complex. Members of the <it>Culex pipiens </it>complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the <it>Ace.2 </it>gene. <it>Culex pipiens quinquefasciatus </it>was the most abundant form collected.</p> <p>Conclusions</p> <p>Important WNV vectors species, <it>Cx. p. pipiens</it>, <it>Cx. p. quinquefasciatus </it>and <it>Cx. tarsalis</it>, are all present in Mexico City. Hybrids of <it>Cx. p. pipiens </it>and <it>Cx. p. quinquefasciatus </it>were also collected and identified. The presence and abundance of these WNV competent vectors is a cause for concern. Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.</p

    Control biológico y mecánico del perforador del fruto de tomate de mesa :neoleucinodes elegantalis.

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    El artículo muestra el desarrollo de un trabajo que pretendía generar opciones tecnológicas sostenibles para el manejo y control del perforador del fruto del tomate N. elegantalis. En este se da a conocer los materiales y métodos, los resultados y discusión donde encontramos el daño por N. elegantalis en frutos, el parasitismo por Trichogramma exigumm sobre huevos de N. elegantalis, el índice de frutos (fructificación) y parámetros de calidad y las conclusiones de este trabajo.Tomate-Solanum lycopersicu

    Endoglin and MMP14 contribute to Ewing sarcoma spreading by modulation of cell-matrix interactions

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    Endoglin (ENG) is a mesenchymal stem cell (MSC) marker typically expressed by active endothelium. This transmembrane glycoprotein is shed by matrix metalloproteinase 14 (MMP14). Our previous work demonstrated potent preclinical activity of first-in-class anti-ENG antibody-drug conjugates as a nascent strategy to eradicate Ewing sarcoma (ES), a devastating rare bone/soft tissue cancer with a putative MSC origin. We also defined a correlation between ENG and MMP14 expression in ES. Herein, we show that ENG expression is significantly associated with a dismal prognosis in a large cohort of ES patients. Moreover, both ENG/MMP14 are frequently expressed in primary ES tumors and metastasis. To deepen in their functional relevance in ES, we conducted transcriptomic and proteomic profiling of in vitro ES models that unveiled a key role of ENG and MMP14 in cell mechano-transduction. Migration and adhesion assays confirmed that loss of ENG disrupts actin filament assembly and filopodia formation, with a concomitant effect on cell spreading. Furthermore, we observed that ENG regulates cell-matrix interaction through activation of focal adhesion signaling and protein kinase C expression. In turn, loss of MMP14 contributed to a more adhesive phenotype of ES cells by modulating the transcriptional extracellular matrix dynamics. Overall, these results suggest that ENG and MMP14 exert a significant role in mediating correct spreading machinery of ES cells, impacting the aggressiveness of the disease.E.A.’s laboratory is supported by ISCIII-FEDER (PI20/00003), CIBERONC (CB16/12/00361), PAIDI-Junta de Andalucía (P18-RT-735), Fundación CRIS Contra el Cáncer, Asociación Candela Riera and Asociación Pablo Ugarte. A.T.A. is supported by Juan de la Cierva Incorporación fellowship (IJC-2018-036767-I); P.P.-C. is sponsored by the Fundación María García Estrada. J.O.-P is supported by Ph.D. Grant Plan Propio from the University of Seville. J.D.-M is supported by CIBERONC (CB16/12/00361). C.S.-A. is supported by the European Social Fund and the Junta de Andalucía (Talento Doctores 2020, DOC_01473). This work was supported by grants from the Consejería de Salud (Junta de Andalucía, grants No PI-0036-2017, PI-0040-2017, and PI-0061-2020) awarded to J.D.-M, A.T.A. and C. S.-A., respectively. This work was also supported by the GEIS-Fundación Mari Paz Jiménez Casado (IV beca trienal) granted to J.D.-M, the 13ª GEIS-Beca Buesa granted to A.T.A. and CRIS (Cancer Research Innovation Spain) granted to J.D.-M and E.A. The laboratory of T.G.P.G. is supported by the Barbara and Wilfried Mohr Foundation. The lab of J.A. is supported by the Instituto de Salud Carlos III (ISCIII), grant number PI20CIII/00020; Asociación Pablo Ugarte, grant numbers TRPV205/18, TPI-M 1149/13; Asociación Candela Riera; Asociación Todos Somos Iván & Fundación Sonrisa de Alex, grant reference: TVP333-19.S

    Development of an immunochromatographic lateral flow dipstick for the detection of Mycobacterium tuberculosis 16 kDa antigen (Mtb-strip)

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    Mycobacterium tuberculosis (Mtb) is a pathogenic bacterium that causes tuberculosis (TB). This contagious disease remains a severe health problem in the world. The disease is transmitted via inhalation of airborne droplets carrying Mtb from TB patients. Early detection of the disease is vital to prevent transmission of the infection to people in close contact with the patients. To date, there is a need of a simple, rapid, sensitive and specific diagnostic test for TB. Previous studies showed the potential of Mtb 16 kDa antigen (Ag16) in TB diagnosis. In this study, lateral flow immunoassay, also called simple strip immunoassay or immunochromatographic test (ICT) for detection of Ag16 was developed (Mtb-strip) and assessed as a potential rapid TB diagnosis method. A monoclonal antibody against Ag16 was optimized as the capturing and detection antibody on the Mtb-strip. Parameters affecting the performance of the Mtb-strip were also optimized before a complete prototype was developed. Analytical sensitivity showed that Mtb-strip was capable to detect as low as 125 ng of purified Ag16. The analytical sensitivity of Mtb-strip suggests its potential usefulness in different clinical applications

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

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    The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations
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